Publications

TitleAbstractYear
Filter
PMID
Filter
effect of different amino acids on the phosphatase system of an ectoparasite: poecilobdella granulosa.inhibitory effect of different amino acids (l-phenylalanine, l-tryptophan, l-tyrosine, l-histidine-monochloride and l-arginine) on the phosphatase system of the brain, ventral nerve cord, stomach and intestine of the indian medicinal leech poecilobdella granulosa, was observed to be substrate, tissue, and inhibitor-specific. most fascinating observation recorded was the activation of alkaline phosphatase of stomach and intestine by certain amino acids at low concentrations. this has been correla ...1977196422
[bioelectrical activity and ultrastructure of medicinal leech retzius neurons during chronic direct and synaptic activation].the threshold direct or synaptic 1/sec stimulation of the retzius cells increases the firing rate of the neuron in the leach. the firing rate becomes synchronized with the stimulation applied. the membrane potential does not change. after 10 min of such stimulation changes occurring in the ultrastructure of neuron are similar to those in a neuron with no stimulation: these changes reveal a decrease in the synthetic processes whereas the bioelectrical activity remains the same which suggests a ce ...1979222633
proteinase inhibitors in severe inflammatory processes (septic shock and experimental endotoxaemia): biochemical, pathophysiological and therapeutic aspects.plasma levels of antithrombin iii, alpha 2-macroglobulin and inter-alpha-trypsin inhibitor, as well as those of various clotting, complement and other plasma factors, were significantly decreased in 18 patients suffering from hyperdynamic septic shock. a similar statistically significant reduction of the concentrations of several plasma factors (prothrombin and antithrombin iii, plasminogen and alpha 2-plasmin inhibitor, complement factor c3 and clotting factor xiii) was observed in experimental ...1979399895
isolation of a collagen fraction from the body-wall glycoproteins of the leech (hirudo medicinalis), and characterization of its carbohydrate--amino acid portion.fractionation of the leech (hirudo medicinalis) body-wall glycoproteins yielded a collagen fraction containing only d-glucose and d-galactose as its carbohydrate constituents. digestion of the collagen with trypsin and pronase, and alkaline degradation of the resulting glycopeptides, gave a product that contained a disaccharide linked to hydroxylysine. mild, acid hydrolysis of the n-acetylated glycopeptides yielded a disaccharide consisting of a d-glucose and a d-galactose residue. various chemi ...1978667877
isolation and characterisation of a low molecular weight inhibitor (of chymotrypsin and human granulocytic elastase and cathepsin g) from leeches.two protein proteinase inhibitors were isolated and purified from the leech hirudo medicinalis by means of gel filtration and ion-exchange chromatography. they inhibit chymotrypsin, subtilisin and the granulocytic neutral proteases elastase and cathepsin g. they proved to be homogeneous in polyacrylamide and dodecylsulfate gel electrophoresis and by end group analysis; only threonine was found as n-terminal amino acid residue using the dansylation technique. these inhibitors, which we call eglin ...1977924384
the connective tissue coverings of leech peripheral nerves: anatomical evidence for the absence of cerebrospinal fluid in the leech.the central nervous system of hirudo medicinalis is contained within a blood vessel, the ventral longitudinal sinus, but the nervous system is separated from the blood by the visceral endothelium. the visceral endothelium possesses many pinocytotic vesicles and basal infoldings and thus appears active whereas the parietal endothelium appears inactive. the junction between the visceral and parietal endothelia is abrupt. peripheral nerves in this animal, as in vertebrates, are covered by endoneuri ...1976993374
the neuron of the fast conducting system in hirudo medicinalis: identification and synaptic connections with primary afferent neurons.a single neuron, located in the center of each segmental ganglion of h. medicinalis is antidromically activated by electrical stimulation of the ventral cord anteriorly and posteriorly to the ganglion, at the same threshold as the fast conducting system (fcs) and with a latency equal to the fcs conduction time. this neuron is activated trans-synaptically by tactile and photic stimulation of the skin and by stimulation of high-threshold fibres running along the cord. a spike evoked by intracellul ...19751156079
[electrical characteristics of the sensory neurons of the medical leech].the electrical characteristics of three types of sensory neurons (n, t and p) were determined in the leech hirudo medicinalis. statistically significant differences were found between the values of tau, cs and rs in the neurons of n- and t-types. the same parameters show the least variation coefficients. the value of time constant (tau) is 17.000-46 ms, the resistivity of the soma membrane trs) is 19.50 kphi-cm2 in t-neurons and 35 kphi-cm2 in n-neurons. the surface of the neurons estimated by t ...19751161108
[structure of the sensory neuropile of the central nervous system of the medical leech hirudo medicinalis]. 19751167104
[medicinal-leech retzius-cell membrane resistance upon prolonged stimulation]. 19761278561
axonal numbers and sizes in the connectives and peripheral nerves of the leech.the present study is an electron microscopic analysis of the numbers and sizes of axons in the connectives and nerves of the medicinal leech. in either the right or left connectives for ganglia 14-18, there are approximately 2860 (+/- 294 s.d.) axons. ninety-seven percent of these axons are less than one micron in diameter. the median connective, faivre's nerve, contains 97 (+/- 3 s.d.) axons, and 94% of these fibers are smaller than one micron. in the peripheral nerve roots for ganglia 14-18, t ...19751150927
[hirudin--comeback of hirudo medicinalis]. 19921366111
tryptophan metabolism and the occurrence of amino acids and serotonin in the leech (hirudo medicinalis) nervous system.the occurrence and distribution of serotonin (5-ht) and amino acids along the central nerve chain of the leech, hirudo medicinalis, was analyzed using dansyl-chloride in order to obtain information on the functional roles of amines and amino acids. there was no statistical variation in the occurrence of most of the amino acids or serotonin in the different parts of the dorsal nerve chain of the leech. a variation in the serotonin content was found during the year with the highest level occurring ...19761084424
an oscillatory neuronal circuit generating a locomotory rhythm.a quartet of interconnected interneurons whose periodic activity appears to generate the traveling body wave of the swimming leech has been identified on each side of segmental ganglia of the ventral nerve cord of hirudo medicinalis. theoretical analysis and electronic analog models of the identified intra- and interganglionic synaptic connections of the segmentally iterated interneurons showed that they form an oscillatory network with cycle period and intra-and intersegmental phase relations a ...19761068483
target influences on the development of leech neurons.a pair of retzius neurons is found in each segmental midbody ganglion of the cns of the leech hirudo medicinalis. although all retzius neurons appear to have the same cell lineage and are indistinguishable from one another through the initial phases of axonogenesis, later in development two pairs of retzius neurons--those in the segments containing the male and female reproductive ducts--acquire distinctive morphological and physiological characteristics. experimental manipulations of the reprod ...19921377423
rhythmic swimming activity in neurones of the isolated nerve cord of the leech.1. repeating bursts of motor neurone impulses have been recorded from the nerves of completely isolated nerve cords of the medicinal leech. the salient features of this burst rhythm are similar to those obtained in the semi-intact preparation during swimming. hence the basic swimming rhythm is generated by a central oscillator. 2. quantitative comparisons between the impulse patterns obtained from the isolated nerve cord and those obtained from a semi-intact preparation show that the variation i ...19761018167
current excitation threshold in sensory neurons of leech central nervous system.1. sensory cells in segmental ganglia of the leech (hirudo medicinalis l.), n (noxious), p (pressure), and t (touch) cells, were stimulated by linearly rising currents. the electrical response to intracellular stimulation with prolonged square-wave currents, the shape of the action potential, and the degree of repetitive activity were also examined. 2. the thresholds for first production of an action potential by linearly rising currents (expressed as multiples of rheobase, i/io), plotted as a f ...1976993825
development of segment- and target-related neuronal identity in the medicinal leech.the rhythmic pumping of the paired heart tubes in the medicinal leech hirudo medicinalis offers an excellent system for studying the development of a simple behavior in terms of its neuronal and muscular components. the present experiments examined the development of identified heart excitor (he) motor neurons during normal embryogenesis. using intracellular impalements and dye-filling, we found that the he motor neurons could be identified at an early stage of development and that they initiall ...19921402613
studies on the fine structure of invertebrate blood vessels. ii. the valves of the lateral sinus of the leech, hirudo medicinalis l.the position, structure and function of the valves within the lateral sinus of the medical leech, hirudo medicinalis, are described on the basis of vital, light- and electron microscopy. in this species the valvular apparatus consists of multiple elongated fir cone-shaped fibrous villi surrounding the orifices of the latero-lateral and latero-dorsal vessel like a tentacular crest. each villus is covered by a thin sheet of a continuous endothelium. the valves prevent the backflow of hemolymph dur ...1976991220
the use of leeches for treatment of venous congestion of the nipple following breast surgery.the medicinal leech, hirudo medicinalis, played a central role in the evolution of medieval and folk medicine. today, for the first time in history, the leech actually has a real and valuable purpose in medicine as a useful adjunct for the plastic surgeon: it provides relief of venous congestion. for over 2000 years, leeches were needlessly applied for a multitude of maladies as an adjunct to blood-letting. their use in europe peaked between 1830 and 1850, however, shortages led to a subsequent ...19921414660
inhibition of plasma kallikrein. kininase and kinin-like activities of preparations from the medicinal leeches.the medicinal leech salivary gland secretion deprived of hirudin antithrombin activity inhibits amidolytic (substrate s-2302) and kininogenase (substrate kininogen) activities of plasma kallikrein, the main component of the intrinsic mechanism of blood coagulation. it therefore possesses high anticoagulant properties. kininase (substrate bradykinin) activity of leech saliva and extracts from the medicinal leeches, as well as kinin-like effects of extracts heated at 100 degrees c have been detect ...19921440537
the pharmacology of extinction.it is impossible to predict what compounds of pharmacological interest may be present in an unexamined species. the extinction of such species may result, therefore, in the loss of therapeutically significant compounds. the fact that science will never know what has been lost does not lessen the significance of the loss. a number of species are discussed to exemplify the potential loss. ginkgo biloba is an ancient plant, apparently saved from a natural extinction by human intervention. from this ...19921453701
quantitative mapping of cutaneous receptive fields in normal and operated leeches, limnobdella.1. the receptive fields and physiological properties of the sensitive cutaneous mechanoreceptive neurones in the leech limnobdella australis were found to be very similar to those previously described in hirudo medicinalis. 2. following separation from the central nervous system (c.n.s.), the distal dendrite stump and cutaneous receptive field remained unchanged for at least 160 days. 3. there was little spreading of receptive fields into regions of skin isolated from the c.n.s. for at least 184 ...1978712326
patterns of activity and the effects of activation of the fast conducting system on the behaviour of unrestrained leeches.1. the neural activity of the nerve cord of hirudo medicinalis has been recorded in unrestrained animals by means of chronically implanted electrodes. 2. the fast conducting system (fcs) is inactive both in motionless animals and during various kinds of active behaviour (creeping, swimming, ventilation). 3. photic and tactile stimuli applied to a motionless animal elicit a fcs discharge, which may be followed by generalized shortening. 4. photic and tactile stimuli applied during ventilation are ...1978712325
neuronal control of swimming in the medicinal leech. v. connexions between the oscillatory interneurones and the motor neurones.a network of intra- and intersegmental synaptic connexions has been identified in the ventral nerve cord of the leech that links the set of oscillatory interneurones of the central swim oscillator to the motor neurones commanding the swimming rhythm. excitatory connexions lead from oscillatory interneurones to both excitatory and inhibitory motor neurones, whereas inhibitory connexions lead from oscillatory interneurones to only the inhibitory motor neurones. connexions leading from a motor neur ...1978702044
neuronal control of swimming in the medicinal leech. iv. identification of a network of oscillatory interneurones.four oscillatory interneurones that appear to be the principal components of the central swim oscillator of hirudo medicinalis have been identified on each side of the segmental ganglia of the ventral nerve cord. during 'swimming' episodes of an isolated nerve cord preparation each interneurone undergoes a polarization rhythm that is phase-locked with the impulse burst rhythm of the motor neurones known to drive the swimming movement. passage of current into any of the interneurones can shift th ...1978702043
[neural control of somatic muscle function in the earthworm, allobophora longa, and in the leech, hirudo medicinalis].studies have been made on the electrical activity of the segmentary nerves and connectives of the abdominal nervous chain in the earthworm and leech. it was shown that the electrical activity of the isolated piece of the abdominal chain of the leech is manifested of periodic outbursts of impulsation. presumably this central periodicity accounts for the discharge-like pattern of muscle rhythmic activity which was revealed in our earlier investigations. the electrical activity in the central nervo ...1978629112
a comparison of receptive and non-receptive plasma membrane areas of photoreceptor cells in the leech, hirudo medicinalis.microvillar (receptive) and external (non-receptive) portions of the plasmalemma of photoreceptor cells of hirudo were compared electron microscopically in thin sections and freeze-fracture replicas. a morphometric approximation showed that the surface area of the microvillar membrane is about 19 times larger than that of the external membrane. the microvillar membrane most probably undergoes extensive membrane turnover. in both segments of the membrane the particles associated with the p- and t ...1979466675
neuronal changes related to behavioral changes in chronically isolated segments of the medicinal leech. 1979455070
the morphological and physiological properties of a regenerating synapse in the c.n.s. of the leech.regeneration of an electrical synapse between particular interneurons in the medicinal leech was traced physiologically and morphologically using intracellular recording the horseradish peroxidase (hrp) injection. the synapse between s-cell interneurons lies in the connective midway between segmental ganglia, so crushing near one ganglion severs only one s-cell's axon. the severed distal stump remains connected to the adjacent uninjured s-cell and continues for weeks to conduct impulses. the inj ...1979438368
mechanisms of ph recovery from intracellular acid loads in the leech connective glial cell.we used double-barrelled, neutral carrier, ph-sensitive microelectrodes to study the mechanisms by which the intracellular ph (phi) is regulated in the connective glial cells of the medicinal leech. in hepes-buffered, nominally co2/hco3(-)-free solutions the recovery of phi from intracellular acidosis is na(+)-dependent and reduced by at least half in the presence of amiloride, suggesting the action of na+:h+ exchange. the rate of phi recovery by this mechanism can be increased by raising the ex ...19921534066
on the distributive patterns of phosphatases and non-specific esterase and their functional aspects amongst the constituents of the photoreceptors of the indian medicinal leech, poecilobdella granulosa (savigny, 1822).in the present contribution the distributive pattern of phosphatases and non-specific esterase amongst the constituents of the leech eye has been revealed and the significance of the enzymatic locales in relation to the visual processes has been discussed. all the phosphatases studied demonstrate absence of the activity in the lens. activity of the phosphatases, however, is restricted to the plasma membrane and associated cytoplasm to varying degrees. the significance of the phosphatases in the ...1978217245
changes in epithelial cells in hirudo medicinalis during wound healing.in the leech, hirudo medicinalis, reepithelialization is an event which takes place early in the wound healing process, immediately after the formation of the pseudoblastema, 4-8 hr postinjury. epithelial cells on the wound margins move into the wound, modifying their phenotypic characteristics. cells lose their columnar shape and become flattened. dermal junctions disrupt and tonofilaments regroup around the nucleus. then, the epithelial cell sheet moves over the newly formed pseudoblastema by ...19921541847
[an electrophysiologic and electron-microscopic study of the electrical connection between the giant nerve cells of the leech hirudo medicinalis]. 1975175306
subcellular calcium localization and at0-dependent ca2+-uptake by smooth endoplasmic reticulum in an invertebrate photoreceptor cell. an ultrastrucutral, cytochemical and x-ray microanalytical study.in hirudo medicinalis an extensive and highly elaborate three dimensional network of smooth endoplasmic reticulum cisternae is found in very close structural relationship to the receptive (microvillar) membrane, as reported for many other invertebrates. a variant of the potassium pyroantimonate technique showed that these submicrovillar endoplasmic reticulum cisternae (smc) and mitochondria are major intracellular calcium stores. furthermore, using saponine-skinned photoreceptors for an in situ ...1979160317
ionic mechanism of 5-hydroxytryptamine induced hyperpolarization and inhibitory junctional potential in body wall muscle cells of hirudo medicinalis.five-hydroxytryptamine (5-ht) causes a hyperpolarization and increased conductance of the leech body wall muscle cell membrane. if 5-ht is applied in the absence of the cl minus ion, the response appears as a depolarization, whereas if 5-ht is applied in the absence of the k+ ion, the response is a hyperpolarization. in both cases, the conductance of the muscle cell membrane is increased. stimulation of the peripheral nerve to the body wall muscle produces a complex junctional potential in muscl ...19762651
adenylate cyclase from hirudo medicinalis segmental ganglia: modulation by physiological and non-physiological agents.1. in hirudo medicinalis segmental ganglia gtp is essential for the full expression of the stimulatory action of serotonin on the adenylate cyclase activity. the amine, in turn, increases the overall affinity of the enzymatic system for gtp. 2. gtp gamma s and gpp(nh)p, non-hydrolysable analogues of gtp, dose-dependently enhance the basal enzyme activity, but impair the stimulatory effect of serotonin. 3. fluoride ions biphasically modulate the leech adenylate cyclase both in the absence and in ...19921363300
a potent inhibitor of platelet activating factor from the saliva of the leech hirudo medicinalis.leech saliva is shown to contain protein platelet aggregation inhibitors and a range of selective low molecular weight (lmw) aggregation inhibitors. gel filtration on bio-gel p-2 (cut-off kda) yields a protein fraction (fr. i) and three lmw fractions. fr. i inhibits aggregation induced by collagen, adp, epinephrine and arachidonic acid. of all the fractions, only one, fr. ii (lmw) specifically inhibits aggregation induced by platelet activating factor (paf, 1-o-alkyl-2-acetyl-sn-glycero-3-phosph ...19921584997
kainate/glutamate-induced changes in intracellular calcium and ph in leech glial cells.kainate evokes a non-desensitizing membrane depolarization in neuropile glial cells of the leech hirudo medicinalis. we measured membrane potential and intracellular ph, ph(i), using double-barrelled ph-sensitive microelectrodes, and intracellular calcium, ca2+i, using the change in fluorescence ratio of intracellularly injected fura-2, in these glial cells in situ. 20-50 microm kainate produced a depolarization of 18-28 mv and a decrease of ph(i) by 0.27 +/- 0.07 ph units. ca2+i increased by 30 ...19921355671
modulatory effects of fmrf-nh2 on outward currents and oscillatory activity in heart interneurons of the medicinal leech.using single-electrode voltage clamp, heart interneurons of the medicinal leech were shown to possess both a rapidly inactivating outward current, ia, and a more slowly inactivating outward current, ik. ia and ik could be separated by their voltage sensitivity and kinetic properties. fmrf-nh2 (phe-met-arg-phe-nh2) modulates ik by shifting both steady state activation and inactivation to more hyperpolarized potentials, but it does not affect the time constants. ia and ik appear to use k+ as a cha ...19921346805
secretion of biologically active leech hirudin from baculovirus-infected insect cells.the thrombin inhibitor, hirudin, from the leech hirudo medicinalis, is the most powerful natural anticoagulant known. it has been characterized as a polypeptide of 65 amino acids which exhibits its anticoagulant properties by binding tightly and specifically to alpha-thrombin. the potency and specificity of hirudin have generated interest on its possible use in the treatment or prophylaxis of various thrombotic diseases. we have used the baculovirus expression system to efficiently produce activ ...19911647362
[monomerization of the fragment d dimer of stabilized fibrin by a secretion from the medicinal leech salivary gland].the salivary gland secretion of the medicinal leech catalyzes the conversion into monomeric form of the fragment d dimer, the product of limited proteolysis of stabilized fibrin. analysis of n-terminal sequences revealed identical fragments for the d-dimer gamma-gamma-chains and the d-monomer gamma-chains formed via this reaction and established the presence of only one n-terminal amino acid (ser). these results provide evidence for the preservation of integrity of the polypeptide chains during ...19921344197
use of the medicinal leech to salvage specialized skin jeopardized by venous impairment. 19911674736
structural differences in active site-labeled thrombin complexes with hirudin isoinhibitors.hirudin, a 65 amino acid polypeptide from the medicinal leech, is the most potent thrombin inhibitor known to date. recently, recombinant forms have been reported, which are as effective as the isolated forms. the studies presented here demonstrate sensitive spectroscopic methods for distinguishing binding of two recombinant hirudins, hv1 and hv2-lys 47, with active site-labeled human alpha-, epsilon- and zeta-thrombins. specifically, fluorosulfonylphenyl nitroxide spin labels, dansyl fluoride a ...19921333213
biochemical characterisation of a pancreatic elastase inhibitor from the leech hirudinaria manillensis.the jawed leech, hirudinaria manillensis is closely related to hirudo medicinalis, both belonging to the same family arhynchobdellida. from hirudo, two potent peptide inhibitors, hirudin (a thrombin inhibitor) and eglin (an elastase/chymotrypsin inhibitor) have been characterised in detail. during our studies to isolate thrombin inhibitor from the leech hirudinaria a potent inhibitor, analogous to eglin, was also detected. results indicate that this inhibitor, which we have named 'gelin', is sig ...19921284966
gas chromatographic-mass spectrometric analysis of biogenic amines in identified neurons and tissues of hirudo medicinalis. 19761255167
in-vitro cleavage of a fusion protein bound to cellulose using the soluble yscfs (kex2) variant.in order to show site-specific cleavage of fusion proteins with an engineered soluble yscf variant, we have constructed a fusion gene encoding eglinc from hirudo medicinalis and the cellulose-binding domain from the cellulomonas fimi exoglucanase (cex). the two fusion partners were separated by a lys-arg-containing recognition sequence for the yeast endoprotease yscf (kex2). the fusion protein (eglinc-cex) was expressed intracellularly in saccharomyces cerevisiae. after disruption of the cells e ...19921368916
fmrfamide effects on membrane properties of heart cells isolated from the leech, hirudo medicinalis.1. the effects of the cardioactive peptide fmrfamide were tested on enzymatically dissociated muscle cells isolated from hearts of the leech. these cells were normally quiescent, with resting potentials near -60 mv. 2. superfusion of fmrfamide induced a strong depolarization in isolated heart cells (e.g., greater than 40 mv with 10(-6) m fmrfamide). the depolarization was maintained in the continued presence of peptide and persisted long after its removal. less frequently, fmrfamide superfusion ...19921373761
differential effects of serotonin depletion on sensitization and dishabituation in the leech, hirudo medicinalis.the goal of these experiments was to test the hypothesis that serotonin (5-ht) is involved in facilitation of the shortening reflex in the leech hirudo medicinalis. for this reason, we have used the toxin 5-hydroxytryptamine (5,7-dht) to deplete serotonin from the nervous systems of intact leeches and have assessed the effect on early facilitation, dishabituation, and sensitization of the touch-elicited shortening reflex using behavioral procedures previously developed in our lab (boulis and sah ...19921378084
leeches to hirulogs and other thrombin-directed antithrombotics.leeches have been used for various medicinal purposes since before written history. bloodletting and leeching declined with the advent of modern medicine. nevertheless, the european medicinal leech has made a comeback in reattachment and plastic surgery. the antithrombotic substance of this leech is the small protein, hirudin, which has recently been cloned and advanced as an antithrombotic. from speculating how hirudin interacted with thrombin and before knowledge of the crystallographic struct ...19921400076
osmotic and ionic regulation during hypoxia in the medicinal leech, hirudo medicinalis l.the concentrations of inorganic and organic ions and osmolality in the blood of the medicinal leech, hirudo medicinalis, were determined during normoxia and hypercapnic and hypocapnic hypoxia. in normoxic animals, the blood sodium concentration was 124.5 +/- 4.2 mmol/l and the total cation concentration was 132.2 +/- 4.3 meq/l (mean +/- s.d.). major anionic compounds were chloride (40.8 +/- 1.6 mmol/l), bicarbonate (8.4 +/- 1.3 mmol/l), and organic anions (42.5 +/- 2.3 meq/l). among the latter, ...19921402736
effects of serotonin and carbachol on glial and neuronal rubidium uptake in leech cns.effects of serotonin (5-ht) and carbachol on rb uptake (used as a k marker) in leech neuron and glia were studied by electron probe microanalysis (epma). hirudo medicinalis ganglia were perfused 60 s in 4 mm rb substituted normal leech ringer's with and without 5-ht (dosage range 5-500 microm) or carbachol (range 10-1000 microm), quench frozen cryosectioned, and subjected to epma to determine elemental mass fractions and cell water content. both 5-ht and carbachol altered leech neuron and glial ...19921472992
analysis and modeling of the multisegmental coordination of shortening behavior in the medicinal leech. i. motor output pattern.1. to understand how a multisegmental animal coordinates motor activity over more than one segment, we studied shortening behavior in the medicinal leech, in which several segments contract longitudinally in response to a moderately strong mechanical stimulus. 2. we first demonstrated that the neuronal activity responsible for shortening behavior occurred in semi-intact and isolated nerve cord preparations, and then characterized the responses of motor neurons in isolated preparations. the motor ...19921479438
analysis and modeling of the multisegmental coordination of shortening behavior in the medicinal leech. ii. role of identified interneurons.1. mechanical stimulation of the leech, hirudo medicinalis, elicits withdrawal behavior that has two components: local bending in the segment stimulated and shortening in outlying segments. local bending is characterized by excitation of longitudinal muscle on one side of the segment and inhibition on the other side. in shortening, all longitudinal muscles are excited. we wished to understand how these distinct motor patterns are produced by a nervous system with segmentally iterated neurons, a ...19921479439
proteinases of the medicinal leech, hirudo medicinalis: purification and partial characterization of three enzymes from the digestive tract.1. three different proteinases were isolated from intestinal extracts of hirudo. 2. the action on synthetic substrates and the effect of various inhibitors indicate that one is a trypsin-like enzyme whereas the other two are chymotryptic. 3. this was confirmed by analysing the degradation of the insulin b-chain. 4. the relative molecular masses of all enzymes are approximately 35,000 and the isoelectric points 9.03, 9.12 and 9.41, respectively. 5. the specific activities assayed with sappna are ...19921499300
x-ray crystal structure of the serine proteinase inhibitor eglin c at 1.95 a resolution.the crystal structure of eglin c, naturally occurring in the leech hirudo medicinalis, is known from its complexes with various serine proteinases, but the crystallization of free eglin c has not yet been reported. a method is described for growing well-diffracting crystals of free eglin c from highly concentrated protein solutions (approximately 200 mg/ml). the space group of the orthorhombic crystals was determined to be p2(1)2(1)2(1) with unit cell parameters a = 32.6, b = 42.0, c = 44.1 a. t ...19921505678
mesenchyme of embryonic reproductive ducts directs process outgrowth of retzius neurons in the medicinal leech.in the two segments of the medicinal leech (hirudo medicinalis) that contain the male (segment 5) and the female (segment 6) reproductive ducts, the paired retzius (rz) neurons are distinguished by several unique properties. for example, the muscles and glands of the body wall are the primary peripheral targets of rz neurons in standard segments [rz(x)], whereas the muscles and glands of the reproductive ducts are the primary peripheral targets of rz neurons in the two reproductive segments [rz( ...19921516742
the use of medicinal leeches in the salvage of flaps with venous congestion.the use of medicinal leeches (hirudo medicinalis) for the salvage of tissues with venous congestion has been intermittent over the last two centuries. during the last decade, interest in leech therapy has undergone a resurgence. hirudo's tricuspid bite injects a highly potent anticoagulant. the site usually bleeds for 1 to 2 hours and under special circumstances may bleed for up to 24 hours. this collective series presents four patients in whom immediate postoperative venous congestion threatene ...19921524375
evidence for glial control of extracellular ph in the leech central nervous system.double-barrelled ph-sensitive microelectrodes were used to measure the intracellular ph (phi) of neuropil glial cells and the ph of extracellular spaces (ph(e)) within isolated, intact ganglia of the leech hirudo medicinalis. by application of a weak acid (propionate, 40 mm) or a weak base (ammonium, 20 mm) the total buffer capacity was estimated by changes in glial phi and in ph(e). the buffering power of glial cells and in the extracellular spaces was increased by up to threefold in the presen ...19921531809
primary structure and function of novel o-glycosylated hirudins from the leech hirudinaria manillensis.hirudin from the leech hirudo medicinalis is a most powerful anticoagulant, and many isoforms have been described. in the present work, the primary structure of two hirudins from the leech hirudinaria manillensis has been elucidated. the antithrombotic activity is similar to that of h. medicinalis hirudins although the sequence identity is below 60%. surprisingly, the hirudins were found to be glycosylated at one site. sugar analysis after methanolysis yielded fucose, galactose, and n-acetylgala ...19921540584
cable properties of arborized retzius cells of the leech in culture as probed by a voltage-sensitive dye.retzius cells of hirudo medicinalis were cultivated on extracellular matrix protein so that extended arborizations were formed. the propagation of voltage transients along 1-microns-thick neurites was observed at a resolution of 8 microns at 10 khz by use of a voltage-sensitive dye. delay and width of the fluorescence transients caused by hyperpolarization of the soma are described by passive spread of voltage in a homogeneous cable (time constant, 10 ms; space constant, 320 microns). the local ...19921549563
bicarbonate-dependent changes of intracellular sodium and ph in identified leech glial cells.a new triple-barrelled ion-sensitive microelectrode was used to investigate the importance of bicarbonate for the regulation of intracellular na+ and ph (nai and phi, respectively) of neuropile glial cells in the central nervous system of the leech hirudo medicinalis. addition of co2/hco3- produced an increase of the nai activity and an intracellular alkalinization, indicating bicarbonate accumulation in the glial cells. changes of external ph (from 7.4 to 7.0 and 7.8) produced large and rapid s ...19921614834
effect of phorbol ester on protein phosphorylation in the central nervous system of the leech hirudo medicinalis: a two-dimensional electrophoretical analysis.1. proteins of different regions of the hirudo medicinalis central nervous system have been analyzed by means of two-dimensional electrophoresis. 2. subcellular distribution of phosphoproteins has been studied in leech segmental ganglia. 3. phorbol 12,13-dibutyrate, a protein kinase c activator, stimulates the phosphorylation of a number of proteins whose isoelectric points and mol. wts are presented. 4. putative roles for these phosphoproteins are discussed.19911790678
calcium transients in identified leech glial cells in situ evoked by high potassium concentrations and 5-hydroxytryptamine.we have recorded the fluorescence of fura-2-loaded, identified glial cells in the neuropile of the central nervous system of the leech hirudo medicinalis using the ratio of emission at 350 nm excitation to that at 380 nm excitation as an indicator of intracellular ca2+ concentration ([ca2+]i). the neuropile glial cells were exposed by mechanically removing the overlying ganglionic capsule and the neuronal cell bodies and were then impaled using a microelectrode under visual control to inject fur ...19921634865
synaptic integration at a sensory-motor reflex in the leech.1. in the medicinal leech the distribution of synapses from the pressure sensory (p) neurone to the annulus erector (ae) motoneurone and the site of impulse initiation in the ae cell were determined to understand better the integration of sensory inputs by the motoneurone. 2. the axon of the ae cell bifurcates before leaving the ganglion. laser photoablation experiments indicated that the axon proximal to the bifurcation is inexcitable. two techniques, laser photoablation and measurement of impu ...19911667805
neuromodulatory effects of acetylcholine and serotonin on the sensitivity of leech mechanoreceptors.1. each segmental ganglion of the leech hirudo medicinalis contains 6 touch (t) cells, 4 pressure (p) cells and 4 nociceptive (n) cells. the receptive terminals of these cells innervate the skin in discrete areas. these cells are known to have extrasynaptic receptors. 2. we tested the effect of transmitter substances present in leech cns on the sensitivity of t and p cells to mechanical stimuli. substances tested included octopamine, fmrfamide, proctolin, substance p, glutamate, gaba, acetylchol ...19911685409
guided outgrowth of leech neurons in culture.sensory neurons of hirudo medicinalis were cultivated on patterns of extracellular matrix (ecm) protein which were prepared by uv irradiation using copper grid masks. the relation of the patterns and of the outgrowth of neurites was observed by scanning electronmicroscopy after gold decoration. the neurites were guided by narrow (10 microm) lanes of ecm protein. branching of neurites was induced by branched lanes. bent neurites were pulled off bent lanes at some distance behind the growth cone s ...19911922972
serotonin is released from isolated leech ganglia by potassium-induced depolarization.1. the quantities of serotonin that are released from isolated leech ganglia in vitro were measured with the sensitive neurochemical techniques of hplc-ec. 2. segmental ganglia were exposed to elevated concentrations of potassium that depolarize leech serotonin-containing neurons by approximately 35 mv per decade. 3. each segmental ganglion released on average 0.20 pmol of serotonin during 10 min of incubation in a solution containing 64 mm k+. 4. the rate of serotonin release increased nearly f ...19911685417
identification of rfamide neuropeptides in the medicinal leech.using a four-step reverse phase hplc separation and ria, five rfamide peptides were purified from cns extracts of the leech hirudo medicinalis. ymrfamide, fmrfamide, ylrfamide, flrfamide, and ggkymrfamide were identified by a combination of antiserum specificity in ria, edman degradation, and mass spectrometry. at least three of these five endogenous peptides can modulate neuromuscular interactions in the leech (38). fmrfamide-like immunoreactivity was selectively released from neural processes ...19911686933
expression of surface glycoproteins early in leech neural development.cell migration and axon growth during neural development rely upon cell-cell and cell-matrix interactions mediated by surface glycoproteins. the surface glycoprotein recognized on leech neurons by monoclonal antibody lan3-2 has previously been implicated in the process of axon fasciculation during regeneration in adults. in adult leeches, lan3-2 binds to a carbohydrate epitope of a 130 kd protein. the present study demonstrates that in embryos the antibody binds to the same carbohydrate epitope ...19901698836
mechanism of action of triethyltin on identified leech neurons.the effects of triethyltin (tet) have been examined using intracellular electrophysiological recording techniques from identified neurons of the leech (hirudo medicinalis) cns and from salivary glands of the giant amazon leech (haementeria ghilianii). tet, at concentrations as low as 10(-5) m, caused a reversible neuronal membrane depolarisation accompanied by an increase in firing frequency of action potentials (which could lead to conduction block at 10(-4) m) and a concomitant decrease in mem ...19901700501
action of fmrfamide on longitudinal muscle of the leech, hirudo medicinalis.1. nerve terminals associated with longitudinal muscle in the leech show fmrfamide-like immunoreactivity. 2. structure-activity studies using fmrfamide analogs show that the c-terminal rfamide portion of the molecule is crucial for biological activity on leech longitudinal muscle. 3. the putative protease inhibitor fa (phe-ala) increases the peak tension produced by longitudinal muscle in response to superfused fmrfamide and the majority of its analogs, suggesting the presence of peripheral prot ...19901976806
segregation of afferent projections in the central nervous system of the leech hirudo medicinalis.sensory axons originating in peripheral tissues converge onto each segmental ganglion in the central nervous system (cns) of the leech, where they segregate into well-defined regions of the synaptic neuropil. here we report on several aspects of the molecular and anatomical organizations of these afferent projections that bear upon the hypothesis that surface markers are involved in organizing these axons as they grow into the cns. first, we show that the distribution of some surface markers in ...19901702106
modification of leech behavior patterns by reserpine-induced amine depletion.a single injection of 100 micrograms reserpine into the crop of the medicinal leech, hirudo medicinalis, reduced cns serotonin and dopamine levels to less than 1% of control values within 3 d. high-pressure liquid chromotography- (hplc) determined cns serotonin and dopamine levels remained maximally depressed for approximately 1 month following reserpine injection. subsequently, amine levels recovered slowly, but remained depressed 6 months after reserpine injection. following reserpine treatmen ...19911986071
development of serotonin-induced ion currents in identified embryonic retzius cells from the medicinal leech (hirudo medicinalis).retzius cells and the cutaneous baroreceptive p-cells of adult medicinal leeches (hirudo medicinalis) respond to 5-ht by cl- as well as by monovalent cation conductances (drapeau et al., 1989). however, chemical synaptic connections between retzius cells (liu and nicholls, 1989) as well as retzius cells and p-cells in culture (drapeau and sanchez-armass, 1988) are mediated by postsynaptic cl- currents in response to 5-ht release from the presynaptic cell. it was the aim of the present study to f ...19911705969
effects of ouabain on intracellular ion activities of sensory neurons of the leech central nervous system.1. the intracellular k+, na+, and ca2+ of mechanosensory neurons in the central nervous system of the leech hirudo medicinalis was measured using double-barreled ion-sensitive microelectrodes. 2. after inhibition of the na(+)-k+ pump with 5 x 10(-4) m ouabain, the intracellular k+ activity (aki) decreased, while the intracellular na+ activity (anai) increased. the input resistance decreased in the presence of ouabain. the intracellular ca2+ increased more than one order of magnitude after ouabai ...19911711107
normally unused positional cues guide ectopic afferents in the leech cns.central projections from peripheral sensory neurons segregate into distinct, ventrally positioned longitudinal tracts within the segmental ganglia of the leech hirudo medicinalis. as documented here, there is an additional tract in the neuropils of the fifth and sixth body ganglia, located at the lateral margin and formed by afferent axons (the "sex afferents") originating from sensory neurons located in the male and female genitalia. ablation of the genitalia results in the complete absence of ...19911744695
electrogenic sodium-dependent bicarbonate secretion by glial cells of the leech central nervous system.the ability to move acid/base equivalents across the membrane of identified glial cells was investigated in isolated segmental ganglia of the leech hirudo medicinalis. the intracellular ph (phi) of the glial cells was measured with double-barreled, neutral-ligand, ion-sensitive microelectrodes during step changes of the external ph (pho 7.4-7.0). the rate of intracellular acidification after the decrease in extracellular ph (pho) was taken as a measure of the rate of acid/base transport across t ...19911761972
segmental differentiation in the leech central nervous system: proposed segmental homologs of the heart accessory neurons.as part of an on-going study of segmental differentiation in the central nervous system (cns) of the leech hirudo medicinalis, a search was made for putative segmental homologs of the heart accessory (ha) neurons, which exist exclusively as a bilateral pair in the ganglia of the fifth and sixth body segments. as it is not yet feasible to obtain adequate cell lineage information in h. medicinalis, potential homologs of the ha neurons were determined using morphological, immunohistochemical, and e ...19911770166
isolation and characterization of hirudin from hirudo medicinalis. 19911771416
comparison of recombinant hirudin and heparin as an anticoagulant in a cardiopulmonary bypass model.recombinant (r) hirudin is a potent thrombin-specific inhibitor originally derived from the natural hirudin of the leech (hirudo medicinalis). we have studied the efficacy of r-hirudin compared to heparin in a dog model of cardiopulmonary bypass (cpb) surgery. two administration regimens were used for r-hirudin: group i received 1.0 mg/kg intracardiac (i.c.) bolus then intravenous (i.v.) bolus at 30 min (n = 10); group ii received 1.0 mg/kg (i.c.) bolus with 1.25 +/- 0.04 mg/kg/h (i.v.) infusion ...19911772977
an objective perspective on recombinant hirudin: a new anticoagulant and antithrombotic agent.leeches have been in medical use for many years. hirudin, the anticoagulant obtained from the medicinal leech has been purified, characterized and can now be produced by recombinant (r) technology. r-hirudin is a potent inhibitor of thrombin and is therefore a potentially valuable anticoagulant and antithrombotic drug. this article reviews the current status of r-hirudin in this role and compares the pharmacokinetics, mechanism of action and clinical efficacy of this agent with heparin. the meth ...19911772981
interaction of hementin with fibrinogen and fibrin.the giant amazon leech haementeria ghilianii manufactures blood anticoagulant which is present in the posterior and anterior salivary glands. the mechanism of blood anticoagulation by haementeria ghilianii is completely different from that used by hirudo medicinalis. the anticoagulant is mostly associated with a fibrinogen-degrading proteinase, hementin. however, other inhibitors of blood coagulation are also present in the salivary glands. the salivary gland extract inhibits platelet aggregatio ...19911772982
destabilase, the novel epsilon-(gamma-glu)-lys isopeptidase with thrombolytic activity.the salivary gland secretion of the leech hirudo medicinalis contains the enzyme destabilase which hydrolyses epsilon-(gamma-glu)-lys cross-links in stabilized fibrin. accumulation of glu residues instead of the original gln residues leads to spontaneous depolymerization of destabilized fibrin. l-gamma-glu-p-nitroanilide; l-gamma-glu-dansylcadaverine and isopeptide epsilon-(gamma-glu)-lys are low-molecular-weight substrates of destabilase. destabilase probably exists in molecular forms of molecu ...19911772985
calin--a platelet adhesion inhibitor from the saliva of the medicinal leech.the saliva of the medicinal leech, hirudo medicinalis, contains a potent, hitherto unsuspected, inhibitor of collagen-mediated platelet adhesion/aggregation. calin, of molecular size approximately 65,000 (reduced), has a rapid (1-10 min) effect on collagen which is reflected in its ability to suppress collagen-induced platelet aggregation, as well as adhesion of platelets to collagen-coated microcarrier beads. it also causes flocculation of type i collagen fibril suspensions. calin is differenti ...19911772988
protease inhibitors in the alimentary tract of the medicinal leech hirudo medicinalis: in vivo and in vitro studies.in individual leeches the flux of labeled serum through the digestive tract was monitored to measure the rate of digestion. a mean value of 10 mg of the original serum (or 2-3 mg of the contents of the foregut) per individual per day was found, which was constant during 10 weeks. on average the serum remained in the intestinum for 20 days. occurrence and concentrations of eglin and bdellin, specific proteinase inhibitors of hirudo, were analyzed after various periods following the ingestion of a ...19921560122
crystal and molecular structure of the bovine alpha-chymotrypsin-eglin c complex at 2.0 a resolution.the crystal structure of the complex between bovine alpha-chymotrypsin and the leech (hirudo medicinalis) protein proteinase inhibitor eglin c has been refined at 2.0 a resolution to a crystallographic r-factor of 0.167. the structure of the complex includes 2290 protein and 143 solvent atoms. eglin c is bound to the cognate enzyme through interactions involving 11 residues of the inhibitor (sites p5-p4' in the reactive site loop, p10' and p23') and 17 residues from chymotrypsin. binding of egli ...19921583684
use of the medicinal leech in the treatment of ear diseases.medicinal leeches (hirudo medicinalis) and the native secretion of their salivary glands diluted with saline (5 times) were successfully used for the treatment of some ear diseases: tinnitus caused by inner-ear affections, acute external otitis and chronic otitis media. the effect of diluted leech saliva injected into the region of the mastoid process by microelectrophoresis was 25-30% lower than that of the medicinal leeches.19921584585
binding of the recombinant proteinase inhibitor eglin c from leech hirudo medicinalis to serine (pro)enzymes: a comparative thermodynamic study.the binding of the recombinant proteinase inhibitor eglin c from the leech hirudo medicinalis to serine (pro)enzymes belonging to the chymotrypsin and subtilisin families has been investigated from the thermodynamic viewpoint, between ph 4.5 and 9.5 and from 10 degrees c to 40 degrees c. the affinity of eglin c for the serine (pro)enzymes considered shows the following trend: leu-proteinase [the leucine specific serine proteinase from spinach (spinacia oleracea l.) leaves] greater than human leu ...19911799460
calcium currents and graded synaptic transmission between heart interneurons of the leech.synaptic transmission between reciprocally inhibitory heart interneurons (hn cells) of the medicinal leech was examined in the absence of na-mediated action potentials. under voltage clamp, depolarizing steps from a holding potential of -60 mv elicited 2 kinetically distinct components of inward current in the presynaptic hn cell: an early transient current that inactivates within 200 msec and a persistent current that only partially decays over several seconds. both currents begin to activate n ...19911848282
distinct receptors, second messengers and conductances underlying the dual responses to serotonin in an identified leech neurone.1. pressure-sensitive mechanosensory (p) neurones of the leech hirudo medicinalis produce two responses to serotonin (5-ht): activation of a cl- conductance and of a non-selective monovalent cation conductance. the effects of channel blockers, the receptor pharmacology and the second-messenger dependence of these responses were studied in voltage-clamped p cells in culture. antagonists were applied by superfusion and agonists by pressure ejection. 2. zn2+ (100 mumol l-1) and h+ (ph 6.5 and lower ...19911849957
specificity determinants for tyrosine protein kinase. a study with recombinant hirudin mutants.hirudin, the powerful anticoagulant agent of leech (hirudo medicinalis) saliva, was readily phosphorylated by two spleen tyrosine protein kinases (tpk-iib and tpk-iii) at tyr63 with km values of 238 microm and 74 microm, respectively. the synthetic tridecapeptide dgdfeeipeeylq, corresponding to the hirudin 53-65 c-terminal fragment, was phosphorylated even more efficiently than hirudin itself. four hirudin mutants, in which one or more of the glutamic acids at positions 57, 58, 61 and 62 have be ...19911935946
characterization, stability and refolding of recombinant hirudin.a recombinant variant of hirudin, the blood-clotting inhibitor of the leech hirudo medicinalis, has been characterized employing spectroscopic and hydrodynamic techniques. conditions have been defined for efficient reconstitution of the native, disulfide-bonded inhibitor from completely unfolded, reduced polypeptide chains. the spectral properties of the native inhibitor are consistent with previous results on the solution structure of hirudin. extremely low circular dichroism in the far ultravi ...19911935981
the oblique muscle organizer in hirudo medicinalis, an identified embryonic cell projecting multiple parallel growth cones in an orderly array.the oblique muscle layer in the leech body wall is built upon the processes of a unique identified embryonic cell, the comb- or c-cell. each c-cell is composed of a spindle-shaped soma that projects approximately 70 parallel processes through the developing body wall at an angle oblique to the long axis. the morphogenesis of this cell and the navigation of its growth cones were examined by intracellular dye filling and antibody staining. at the earliest stages described each c-cell had about six ...19911936570
old and new natural products as the source of modern antithrombotic drugs.natural compounds have been the first historical source of antithrombotic compounds (heparin, vitamin k antagonists, streptokinase, urokinase); molecules extracted from plants or animals still provide some of the most original and promising approaches for the discovery of new drugs in this class. in this review, we will briefly describe three examples of current research trends that could lead to the development of new antithrombotic drugs of natural origin. flavonoids have been shown to be inhi ...19911956960
initiation of swimming activity in the medicinal leech by glutamate, quisqualate and kainate. 19901980514
potential use of recombinant hirudin as an anticoagulant in a cardiopulmonary bypass model.recombinant (r) hirudin is a potent thrombin-specific inhibitor derived from the natural hirudin of the leech (hirudo medicinalis). we have studied the efficacy of r-hirudin compared with heparin in a canine model of cardiopulmonary bypass operations. two administration regimens were used for r-hirudin: group 1, 1.0 mg/kg intracardiac bolus then intravenous bolus at 30 minutes (n = 10); and group 2, 1.0 mg/kg intracardiac bolus with 1.25 +/- 0.04 mg.kg-1.h-1 intravenous infusion (n = 8). group 3 ...19911989543
aeromonas, acclimation, and penicillin as complications when leeches are applied to skin flaps in rabbits.the medicinal leech, hirudo medicinalis, has been recognized by plastic surgeons for its ability to reduce congestion and improve blood flow in grafted skin flaps by withdrawing excess blood. the leech's ability to digest blood is due to the presence of aeromonas hydrophila in the gut of the leech. in this report we describe the occurrence of aeromonas hydrophila septicaemia in rabbits used in a study to evaluate the efficacy of the medicinal leech on abdominal skin flap survival. in new zealand ...19902366512
mechanism of cl- sensitivity in internal ion receptors of the leech: an inward current gated off by cl- in the nephridial nerve cells.the nephridial nerve cells of the leech, hirudo medicinalis, 34 sensory cells, each associated with one nephridium, are sensitive to changes in extracellular cl- concentration, an important factor in ion homeostasis. using single-electrode current- and voltage clamp and ion substitution techniques, the specificity and mechanism of cl- sensitivity of the nephridial nerve cell was studied in isolated preparations. increase of the normally low external cl- concentration leads to immediate and susta ...19912033568
two forms of sensitization of the local bending reflex of the medicinal leech.sensitization of the local bending reflex of the medicinal leech hirudo medicinalis was studied in a semi-intact preparation in which behavioral and electrophysiological recordings were made simultaneously. 1. sensitization of local bending could be produced in two ways: by repeated stimulation of the mechanoreceptor sensitive to pressure (the p cell), and by stimulation of the mechanoreceptor sensitive to noxious stimuli (the n cell). 2. both forms of sensitization produced a central neuronal c ...19912046043
Displaying items 1 - 100 of 1013