Publications

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catarrhal proventriculitis associated with a filamentous organism in pet birds.catarrhal proventriculitis due to infection by an unidentified organism was diagnosed in 79 of 534 pet birds examined histologically. it was more prevalent in domestic birds (70 cases) than in imported ones (9 cases). a high incidence of the disease was encountered in budgerigars (melopsittacus undulatus) and it was occasionally found in finches (poephila gouldiae gouldiae), parakeets (psittacula krameri manillensis), amazona parrots (amazona aestiva aestiva) and cockatiels (nymphicus hollandicu ...19921297007
histopathological survey of protozoa, helminths and acarids of imported and local psittacine and passerine birds in japan.a total of 534 psittacine and passerine birds consisting of 241 imported and 293 local birds were examined histologically. as a result, the following parasites were found: giardia (86 cases), knemido-coptes (26 cases), coccidia (10 cases), ascaridia (6 cases), cryptosporidium (5 cases), sarcocystis (5 cases), tapeworm (4 cases), microfilaria (2 cases), hexamita (1 case), and spiroptera (1 case). high incidences of giardiasis and knemido-coptic infestation were detected in the local birds, but ra ...19921297009
respiratory adenovirus-like infection in a rose-ringed parakeet (psittacula krameri).intranuclear inclusions were observed under light microscopy in the bronchial epithelial cells of a recently purchased female rose-ringed parakeet that died of chlamydiosis. transmission electron microscopy revealed the presence of numerous particles of adenovirus morphology. a latent adenovirus infection may have become more severe following chlamydiosis and the stress of handling.19911664716
occurrence of keratinophilic fungi on indian birds.keratinophilic fungi were isolated from feathers of most common indian birds, viz. domestic chicken (gallus domesticus), domestic pigeon (columba livia), house sparrow (passer domesticus), house crow (corvus splendens), duck (anas sp.), rose-ringed parakeet (psittacula krameri). out of 87 birds, 58 yielded 4 keratinophilic fungal genera representing 13 fungal species and one sterile mycelium. the isolated fungi were cultured on sabouraud's dextrose agar at 28 +/- 2 degrees c. chrysosporium speci ...19911726608
hematological changes produced by lindane (gamma-hch) in six species of birds.hematological changes were studied after oral administration of lindane (gamma-hexachlorocyclohexane) at 5 mg/kg body weight twice in 1 week in 6 species of agriculturally important birds: house sparrow, baya weaver bird, common myna, rose-ringed parakeet, blue rock pigeon and domestic duck. lindane induced anemia in the birds as judged by reduced rbc count, hematocrit and hemoglobin content with corresponding changes in mcv, mch and mchc. bleeding and clotting time were markedly prolonged. sple ...19862424143
influence of age and splanchnic nerve on the action of melatonin in the adrenomedullary catecholamine content and blood glucose level in the avian group.a single intraperitoneal (ip) melatonin injection (0.5 mg/100 g body wt.) caused an increase in norepinephrine (ne) fluorescence and elevation of ne content in newly-hatched pigeons (columba livia), but a reduction of ne fluorescence and depletion of ne content in the adrenal medulla of newly-hatched crows (corvus splendens) after 0.5 h of treatment. in contrast, in adults melatonin caused increase in ne fluorescence and elevation of ne content only in the parakeet (psittacula krameri). half an ...19883249022
lithium-induced alterations in the testis of the male roseringed parakeet (psittacula krameri) : evidence for significant structural changes and disruption in the spermatogenetic activity.in this report, we have examined the effects of lithium on testicular morphology in a male subtropical wild avian species, the roseringed parakeet (psittacula krameri). adult male birds were collected during the months of february-march, a time when the testicular gametogenic activity in these seasonally breeding birds is at its peak. they were injected, intramuscularly, twice daily (07:00 and 19:00 h) with lithium chloride (sigma chemical company) at a dosage of 0.5 meq/kg body weight either fo ...199910098592
cryptosporidium meleagridis in an indian ring-necked parrot (psittacula krameri).to perform a morphological and genetic characterisation of a cryptosporidium infection in an indian ring-necked parrot (psittacula krameri) and to compare this with c meleagridis from a turkey.200010860158
the sensitivities of various erythrocytes in a haemagglutination assay for the detection of psittacine beak and feather disease virus.the erythrocytes of various species were tested in psittacine beak and feather disease (pbfd) virus haemagglutination (ha) and haemagglutination inhibition assays to determine which are suitable for use in these assays. ha activity was observed for erythrocytes of the salmon-crested cockatoo, the sulphur-crested cockatoo, the umbrella cockatoo, the goffin's cockatoo and the cockatiel, with differences amongst individuals within species, but not for erythrocytes of humans, the pig, the guinea pig ...200011014065
imported parakeets harbor h9n2 influenza a viruses that are genetically closely related to those transmitted to humans in hong kong.in 1997 and 1998, h9n2 influenza a viruses were isolated from the respiratory organs of indian ring-necked parakeets (psittacula krameri manillensis) that had been imported from pakistan to japan. the two isolates were closely related to each other (>99% as determined by nucleotide analysis of eight rna segments), indicating that h9n2 viruses of the same lineage were maintained in these birds for at least 1 year. the hemagglutinins and neuraminidases of both isolates showed >97% nucleotide ident ...200111238878
cryptococcosis outbreak in psittacine birds in brazil.an outbreak of cryptococcosis occurred in a breeding aviary in são paulo, brazil. seven psittacine birds (of species charmosyna papou, lorius lory, trichoglossus goldiei, psittacula krameri and psittacus erithacus) died of disseminated cryptococcosis. incoordination, progressive paralysis and difficulty in flying were seen in five birds, whereas superficial lesions coincident with respiratory alterations were seen in two birds. encapsulated yeasts suggestive of cryptococcus sp. were seen in faec ...200415473361
attempted photodynamic therapy against patagial squamous cell carcinoma in an african rose-ringed parakeet (psittacula krameri).a 5-yr-old female african rose-ringed parakeet (psittacula krameri) presented with an ulcerated mass in the medial postpatagial area of the right wing. biopsy specimens of the mass demonstrated a well-differentiated squamous cell carcinoma. photodynamic therapy resulted in tumor cell necrosis and initial reduction in tumor burden, but complete remission was not achieved. based on this and other avian cases, it appears that photodynamic therapy designed to eradicate squamous cell carcinoma in avi ...200718229870
respiratory herpesvirus infection in two indian ringneck parakeets.a flock of indian ringneck parakeets (psittacula krameri manillensis) was imported to the united states from australia. soon after, 1 parakeet suddenly died, and a second parakeet died after a 2-day course of illness, which consisted of anorexia, lethargy, emaciation, and dyspnea. at necropsy, the affected birds had diffuse consolidation and red discoloration of the lungs, as well as thickened, congested air sacs. the microscopic examination revealed multifocal, necrotizing bronchitis, parabronc ...200818319441
eye lesions in pet birds.amongst eye lesions in birds that died in quarantine, cataracts were the most common disorders (37/241, 15.4%), being prevalent in the annular pads of cockatiels (nymphicus hollandicus), amazon parrots (amazona aestiva aestiva) and budgerigars (melopsittacus undulatus). the incidence in male birds was more than twice that in females. deposition of crystals, mostly in the cornea, was the second most frequent lesion (21/293, 8.7%), mainly found in cockatiels, parakeets (psittacula krameri manillen ...199318671000
herpesvirus infections in psittacine birds in japan.herpesvirus infection was diagnosed histologically and electron microscopically in 21 out of 241 pet birds examined. the infected birds included 14 parakeets (psittacula krameri manillensis) with respiratory infection and three parrots (ama-zona aestiva aestiva), two cockatiels (nymphicus hollandicus) and two rosellas (platycercus emimius) with pacheco's disease. the consistent lesions of respiratory herpesvirus infection were the formation of syncytial cells associated with the presence of intr ...199318671003
pathological studies on chlamydiosis in parakeets (psittacula krameri manillensis).histological, immunohistochemical and ultrastructural findings are described in 20 parakeets (psittacula krameri ntanillensis) affected with chlamydiosis. the main histological lesions consisted of focal necrosis in the liver and adrenal gland, lymphocytic depletion with fibrin exudation in the splenic sinuses and follicles and fibrinopurulent airsacculitis. in these lesions basophilic chlamydial inclusion bodies were found. macrophages and plasma cells increased mainly in the liver and spleen. ...199018679944
alien invasive birds.a bird species is regarded as alien invasive if it has been introduced, intentionally or accidentally, to a location where it did not previously occur naturally, becomes capable of establishing a breeding population without further intervention by humans, spreads and becomes a pest affecting the environment, the local biodiversity, the economy and/or society, including human health. european starling (sturnus vulgaris), common myna (acridotheres tristis) and red-vented bulbul (pycnonotus cafer) ...201020919578
Molecular characterisation of an avihepadnavirus isolated from Psittacula krameri (ring-necked parrot).Avihepadnaviruses have been documented previously in ducks, herons, geese, storks and cranes. Here, we describe the full genome of a new avihepadnavirus isolated from Psittacula krameri (ring-necked parrot) in Poland. The parrot hepatitis B virus (PHBV) genome (3042 bp) shares <76% sequence identity with other avihepadnavirus isolates and is phylogenetically most closely related to heron and stork hepatitis B viruses isolates. PHBV has a genome organization similar to that of other hepadnaviruse ...201122183110
environmental, dietary, and hormonal factors in the regulation of seasonal breeding in free-living female indian rose-ringed parakeets (psittacula krameri).the roles of environmental, dietary, and hormonal factors in the timing of seasonal breeding were assessed in free-living female indian rose-ringed parakeets, psittacula krameri, in northwest india (22 degrees 2'n, 73 degrees e). the ovaries and oviducts began to enlarge in january, were fully developed in february, and began to regress in march. during this time there was no significant change in the concentration of plasma luteinizing hormone (lh) or estradiol. the concentration of plasma lh d ...20113235067
adrenocortical responses to sex hormonal administration in three avian species: the parakeet psittacula krameri, the quail coturnix cotournix & the common myna acridotheres tristis. 2003151665
environmental and hormonal factors in seasonal breeding in free-living male indian rose-ringed parakeets (psittacula krameri).seasonal changes in testicular activity, plasma luteinizing hormone (lh), estradiol (e2), testosterone (t), and 5 alpha-dihydrotestosterone (5 alpha-dht) were related to pair bond formation, nest building, nest defense, and parental behavior in free-living indian rose-ringed parakeets (psittacula krameri) in northwest india. spermatozoa production occurred between january and march when daylengths were short (10-12 hr) and ambient temperature was seasonally low (8-20 degrees c). at other times o ...20113235065
avian polyomavirus genome sequences recovered from parrots in captive breeding facilities in poland.eight genomes of avian polyomaviruses (apvs) were recovered and sequenced from deceased psittacula eupatria, psittacula krameri, and melopsittacus undulatus from various breeding facilities in poland. of these apv-positive samples, six had previously tested positive for beak and feather disease virus (bfdv) and/or parrot hepatitis b virus (phbv).201526404592
pcr-based diagnosis, molecular characterization and detection of atypical strains of avian chlamydia psittaci in companion and wild birds.chlamydiosis is one of the most important infectious diseases of birds. in this study, 253 clinical samples were taken from 27 bird species belonging to seven orders. thirty-two (12.6%) samples were positive for chlamydia psittaci major outer membrane gene (ompa) dna by a nested polymerase chain reaction (pcr). twelve nested pcr-positive specimens were typed by ompa gene-based pcr-restricted fragment length polymorphism, using ctu/ctl primers and alui restriction enzyme. four restriction pattern ...201323391180
nest-site competition between invasive and native cavity nesting birds and its implication for conservation.nesting cavities are often a limited resource that multiple species use. there is an ongoing discussion on whether invasive cavity nesting birds restrict the availability of this key limited resource. while the answer to this question has important conservation implications, little experimental work has been done to examine it. here, we aimed to experimentally test whether alien cavity nesting birds affect the occupancy of cavities and the resulting breeding success of native cavity breeders in ...201627341373
biomonitoring of heavy metals in feathers of eleven common bird species in urban and rural environments of tiruchirappalli, india.heavy metals continue to remain as a major environmental concern in spite of emission control measures. in this study, we analyzed the concentrations of heavy metals (fe, cr, mn, ni, cu, zn, and cd) in the feathers of 11 species of birds collected from urban and rural areas of tiruchirappalli, southern india. metal concentrations followed the order: fe > cu > zn > cr > mn > ni > cd. irrespective of sample locations, heavy metals such as fe, cr, ni, zn, and cu were detected in high concentrations ...201525893764
preliminary study on avian fauna of the krishna river basin sangli district, western maharashtra, india.the present study on avifaunal diversity carried out for three years at the krishna river basin, sangli district revealed a total of 126 species of birds belonging to 30 families, of which 91 species were resident, 16 migratory, 12 resident and local migratory and 7 species were resident and migratory. among the migrant birds, rosy starling sturnus roseus was dominant in the study area. commonly recorded resident bird species were, red vented bulbul, jungle crow, house sparrow, common myna, brah ...201425522499
histomorphology and proteolytic activity in the gastric apparatus of frugivorous, carnivorous and omnivorous species of birds.the histomorphology of the gastric apparatus, the pepsin level and the optimum ph for pepsin were investigated in psittacula krameri (frugivore), lanius schach (carnivore) and acridotheres tristis (omnivore) species of birds. the proventricular glands were found to be made up of oxynticopeptic cells. the lobules of the oxynticopeptic cells are polyhedral; they are the largest in p. krameri, and the smallest in a. tristis. however, their greater number in a. tristis enables a higher secretion of ...197616419
loss of the gene for the alpha subunit of atp synthase (atp5a1) from the w chromosome in the african grey parrot (psittacus erithacus).this study describes the results of an analysis using southern blotting, the polymerase chain reaction, and sequencing which shows that the african grey parrot (psittacus erithacus) lacks the w-chromosomal gene for the alpha subunit of mitochondrial atp synthase (atp5a1w). additional evidence shows that in other psittacines a fragment of the atp5a1w gene contains five times as many nonsynonymous nucleotide replacements as the homologous fragment of the z gene. therefore, whereas in these other p ...200111479684
experimental evidence of impacts of an invasive parakeet on foraging behavior of native birds.resource competition is one potential behavioral mechanism by which invasive species can impact native species, but detecting this competition can be difficult due to the interactions that variable environmental conditions can have on species behavior. this is particularly the case in urban habitats where the disturbed environment can alter natural behavior from that in undisturbed habitats. the rose-ringed parakeet (psittacula krameri), is an increasingly common invasive species, predominantly ...201424822022
foot preferences in wild-living ring-necked parakeets (psittacula krameri, psittacidae).evidence for foot preferences has been reported in parrots and the majority of parrot species uses the left foot to hold and process food objects. here we assessed the footedness of ring-necked parakeets (psittacula krameri) in a wild-living non-native population in heidelberg, baden-wurttemberg, germany. observations were made when parrots fed on catalpa trees catalpa sp., with 20- to 50-cm-long fruits. parakeets tend to bite off catalpa fruits with their beak, using one foot holding the fruit. ...201120521200
influence of photoperiods on glycemic and adrenal catecholaminergic responses to melatonin administrations in adult male roseringed parakeets, psittacula krameri neumann.effects of daily (one hour prior to onset of darkness) injection of melatonin (25 micrograms/100 g body wt. for 30 days) on concentrations of blood glucose and adrenal catecholamines were studied in adult male roseringed parakeets, p. krameri under both natural (np; about 12l:12d) and artificial long (lp; 16l:8d; lights were available in between 0600 and 2200 hrs) or short (sp; 8l:16d; lights were available between 0600 and 1400 hrs) photoperiodic conditions. the results indicate that neither lp ...200011395954
influences of graded dose of melatonin on the levels of blood glucose and adrenal catecholamines in male roseringed parakeets (psittacula krameri ) under different photoperiods.effects of daily evening (just before the onset of darkness in a 24 h light dark cycle) administration of graded doses (25, 50, or 100 microg/100 g body wt./day for 30 days) of melatonin on the concentrations of blood glucose and adrenal catecholamines were studied in sexually active male roseringed parakeets under natural (np; approximately 12l: 12d) and artificial long (lp; 16l: 8d) and short (sp; 8l: 16d) photoperiods. blood samples and adrenal glands were collected from each bird during the ...200011262603
importance of photoperiods in determining temporal pattern of annual testicular events in rose-ringed parakeet (psittacula krameri).male rose-ringed parakeets (psittacula krameri) were transferred to a long photoperiod (lp; ld 16:8) or a short photoperiod (sp; ld 8:16) for 45 or 90 days on four dates corresponding to the beginnings of different reproductive phases in an annual testicular cycle, and testicular responsiveness was evaluated by comparison with the testicular volume, weight, seminiferous tubular diameter, and germ cell profiles of birds in a natural photoperiod (np). exposure of birds to lp during the progressive ...19921571590
occurrence of ornithonyssus sylviarum in pet birds from the district of setúbal, portugal.ornithonyssus sylviarum is a blood-feeding ectoparasite of birds and the most serious pest in poultry farms in north america. although the mites are typically adapted to temperate climates, information on this mite in europe is sparse, and dermanyssus gallinae is considered to be the only mite impacting the poultry industry. the present study reports the occurrence of o. sylviarum in pet birds in portugal. mites were collected directly from birds and with traps placed in cages and nests at 20 di ...201728523489
interference competition between an invasive parakeet and native bird species at feeding sites.interference competition has proved to be a factor of successful establishment of invasive species. this type of competition may have a stronger impact when native species have temporal niche overlap with the invasive species. the ring-necked parakeet psittacula krameri has been successfully introduced in many countries and its interspecific agonistic behavior has already been reported. the purpose of this study is to analyze the territorial and preemptive interference competition between the ri ...201627829702
ancestral origins and invasion pathways in a globally invasive bird correlate with climate and influences from bird trade.invasive species present a major threat to global biodiversity. understanding genetic patterns and evolutionary processes that reinforce successful establishment is paramount for elucidating mechanisms underlying biological invasions. among birds, the ring-necked parakeet (psittacula krameri) is one of the most successful invasive species, established in over 35 countries. however, little is known about the evolutionary genetic origins of this species and what population genetic signatures tell ...201526172573
crowding in the city: losing and winning competitors of an invasive bird.invasive species can take advantage of resources unexploited by natives (opportunism hypothesis) or they can exploit the same resources but more aggressively or efficiently (competition hypothesis), thus impacting native species. however, invasive species tend to exploit anthropogenic habitats that are inefficiently used by natives such as urban environments. focusing on the ring-necked parakeet (psittacula krameri), one of the most invasive birds worldwide, we combined observations of interspec ...201424945439
testicular biopsy in psittacine birds (psittaciformes): impact of endoscopy and biopsy on health, testicular morphology, and sperm parameters.histologic examination of a testicular biopsy sample may be required to evaluate the reproductive status of male psittacine birds. the purpose of this study was to evaluate the viability of testicular sampling from live birds by assessing the impact on the birds' health, testicular integrity, and sperm quality. testicular biopsy samples were obtained by endoscopy 4 times during 12 months from 9 cockatiels (nymphicus hollandicus) and 7 rose-ringed parakeets (psittacula krameri). only 2 of 16 bird ...201324640926
testicular biopsy in psittacine birds (psittaciformes): comparative evaluation of testicular reproductive status by endoscopic, histologic, and cytologic examination.knowledge of the reproductive cycle of male parrots is important for examining the male genital tract and for successful breeding, especially of endangered species. to evaluate different diagnostic methods and criteria concerning the classification of reproductive stages, we examined 20 testicular samples obtained at necropsy in psittacine birds of different species and testicular biopsy samples collected from 9 cockatiels (nymphicus hollandicus) and 7 rose-ringed parakeets (psittacula krameri) ...201324640925
improved clinicopathologic assessments of acute liver damage due to trauma in indian ring-necked parakeets (psittacula krameri manillensis).increased activities of certain biochemical enzymes (alanine aminotransferase [alt], aspartate aminotransferase [ast], lactate dehydrogenase [ldh], alkaline phosphatase [alp]) have been associated with blunt liver injury in many species. to evaluate changes in plasma hepatic biochemical parameters in acute avian liver disease caused by trauma and to compare biochemical changes with histologic lesions in hepatic parenchyma, 30 healthy fasted indian ring-necked parakeets (psittacula krameri manill ...201222872978
[endocrinologic studies of male psittacine birds for the evaluation of their reproductive status].evaluating methods of hormone measurement in different specimens of male parrots in order to assess their reproductive status and stress axis.201122143663
purification, crystallization and preliminary x-ray diffraction studies of parakeet (psittacula krameri) haemoglobin.birds often show efficient oxygen management in order to meet the special demands of their metabolism. however, the structural studies of avian haemoglobins (hbs) are inadequate for complete understanding of the mechanism involved. towards this end, purification, crystallization and preliminary x-ray diffraction studies have been carried out for parakeet hb. parakeet hb was crystallized as the met form in low-salt buffered conditions after extracting haemoglobin from crude blood by microcentrifu ...200919851014
reproductive success of rose-ringed parakeets psittacula krameri in a captive uk population.rose-ringed parakeets psittacula krameri (scop.) have recently become established in several european countries, with potential for significant negative economic and ecological impacts. however, in northern europe the potential for reproductive output is largely unknown. in 2005 the authors established a captive outdoor colony in north-east england and examined breeding success over 2 years.200919623541
tolerance doses of cutaneous and mucosal tissues in ring-necked parakeets (psittacula krameri) for external beam megavoltage radiation.currently used dosages for external-beam megavoltage radiation therapy in birds have been extrapolated from mammalian patients and often appear to provide inadequate doses of radiation for effective tumor control. to determine the tolerance doses of cutaneous and mucosal tissues of normal birds in order to provide more effective radiation treatment for tumors that have been shown to be radiation responsive in other species, ingluvial mucosa and the skin over the ingluvies of 9 ring-necked parake ...200919530400
effect of photoperiod on the adrenal activities of male rose ringed parakeet, psittacala krameri.adult male rose ringed parakeets were exposed to very long photoperiod (22 hr l: 2 hr d) and very short photoperiod (2 hr l: 22 hr d) daily for 60 days during different phases of the annual testicular cycle. adrenal activities of the experimental birds were compared with that of parallel held natural photoperiodic birds. marked atrophy of adrenocortical cells was noted in the glands of long photoperiod (22 hr l:2 hr d) during different phases, i.e., post-breeding, quiescent and pre-breeding phas ...200818972688
the pineal gland, but not melatonin, is associated with the termination of seasonal testicular activity in an annual reproductive cycle in roseringed parakeet psittacula krameri.the role of the pineal gland and its hormone melatonin in the regulation of annual testicular events was investigated for the first time in a psittacine bird, the roseringed parakeet (psittacula krameri). accordingly, the testicular responsiveness of the birds was evaluated following surgical pinealectomy with or without the exogenous administration of melatonin and the experimental manipulations of the endogenous levels of melatonin through exposing the birds to continuous illumination. an iden ...200617050209
sedative effects of midazolam and xylazine with or without ketamine and detomidine alone following intranasal administration in ring-necked parakeets.to evaluate the effects of intranasal administration of midazolam and xylazine (with or without ketamine) and detomidine and their specific antagonists in parakeets.200616448361
induction of blindness by formoguanamine hydrochloride in adult male roseringed parakeets (psittacula krameri).formoguanamine (2,4-diamino-s-triazine) was known to be an effective chemical agent in inducing blindness in poultry chicks, but not in adult birds. the present study was undertaken to demonstrate the influences, if any, of this chemical on the visual performance and retinal histology in an adult sub-tropical wild bird the roseringed parakeet (psittacula krameri). formoguanamine (fg) hydrochloride was subcutaneously injected into adult parakeets at the dosage of 25 mg (dissolved in 0.75 ml physi ...200212571374
epichlorohydrin induced biochemical changes in the rose-ringed parakeet, psittacula krameri scopoli.intraperitoneal administration of epichlorohydrin (ech) at the dose level of 20 and 50 mg/kg body weight inhibited spermatogenesis in the testis of parakeet during breeding season. a total load of 60 mg/kg body weight of ech given on 3 consecutive days proved to be lethal. testicular proteins, nucleic acids (dna and rna), phospholipids and acid phosphatase activity were decreased, while the lipids, total cholesterol and alkaline phosphatase activity increased after ech administration. the result ...199910709325
castration and testosterone induced changes in the pinealocytes of roseringed parakeet, psittacula krameri, during different phases of the annual testicular cycle.the pinealocytes in male roseringed parakeets (psittacula krameri) were studied following bilateral castration and/or therapeutic administration of testosterone during the preparatory (june-july), progressive (nov.-dec.), pre-breeding (jan.-feb.) and breeding (march-april) phases of the annual testicular cycle. the responses of the pineal to either treatment were found to be almost identical throughout the investigation. in each reproductive phase, the pineal appeared to be hypertrophied followi ...19948085660
fine structure of the free-living parakeet pineal in relation to the breeding cycle.seasonal changes in the ultrastructure of the free-living rose-ringed parakeet psittacula krameri pineal were examined in relation to the sub-tropical environment and seasonal reproduction. dark and light pinealocytes of the presumptive neuroendocrine cell line predominated, while supporting cells, ependymal cells, myelinated and non-myelinated nerve fibers with nerve endings, and regressed photoreceptor elements were also observed. unlike in pineals of many animals, particularly mammals, the pr ...19938106957
primary structure of the hemoglobin beta-chain of rose-ringed parakeet (psittacula krameri).the primary structure of rose-ringed parakeet hemoglobin beta-chain was established, completing the analysis of this hemoglobin. comparison with other avian beta-chains show variations smaller than those for the corresponding alpha-chains. there are 11 amino acid exchanges in relationship to the only other characterized psittaciform beta-chain, and a total of 35 positions are affected by differences among all avian beta-chains analyzed (versus 61 for the alpha-chains). at three positions, the ps ...19892803513
primary structure of the hemoglobin alpha-chain of rose-ringed parakeet (psittacula krameri).the structure of the hemoglobin alpha-chain of rose-ringed parakeet was determined by sequence degradations of the intact subunit, the cnbr fragments, and peptides obtained by digestion with staphylococcal glu-specific protease and trypsin. using this analysis, the complete alpha-chain structure of 21 avian species is known, permitting comparisons of the protein structure and of avian relationships. the structure exhibits differences from previously established avian alpha-chains at a total of 6 ...19883255379
the effect of a mao inhibitor on reserpine-induced secretion of catecholamines from the adrenal medulla of the rose-ringed parakeet.the effect of mao inhibitor on reserpine-induced release of catecholamines from the adrenal medulla of the rose-ringed parakeet was investigated in this biochemical, histochemical, and ultrastructural study. the mao inhibitor provided some blockade of epinephrine secretion and was ineffective in blocking norepinephrine secretion. differences between birds and mammals were noted, suggesting that different mechanisms of catecholamine release may be operating in the two classes.19836850749
diurnal rhythm in differential leucocyte population in adult male rose-ringed parakeet. 19827200219
islets of langerhans in the parakeet, psittacula krameri.the pancreatic gland of psittacula krameri is divisible into 4 lobes i.e. dorsal, ventral, third and splenic. the endocrine part is composed of alpha 1-, alpha 2- and beta-cells. the islets are of 4 kinds viz., alpha islets (having alpha 1- and alpha 2-cells), beta islets (having beta- and alpha 1-cells), pure beta islets (consisting of beta-cells exclusively) and mixed islets (with beta-, alpha 1- and alpha 2-cells). the distribution of alpha islets is mostly restricted to the splenic and third ...19806994526
histochemical study of the distribution of a few enzymes in the digestive system of indian parrot.acid-and alkaline phosphatase, 5-nucleotidase and lipase have been localized histochemically in the gizzard, intestine liver and pancreas of indian parrot, psittacula krameri. in the gizzard and intestine, the mucosal epithelial cells are the main sites for the enzyme production. the tubular glands of the gizzard show intense reaction for all the enzymes tested. the hepatic sinusoid cells of the liver and the acinii of pancreas give positive reaction. like pancreas, the intestine has also been f ...1977404819
neurohypophysial-adrenal gland responses to water-deprivation in the rose-ringed parakeet.the aim of the present investigation is to study the relative influence of neuohypophysis, adrenal cortex and adrenal medulla under dehydration stress in the parakeet. birds subjected to dehydration for 7 days lost body weight. neurosecretory material (nsm) was partially depleted from the neurohypophysis. adrenal gland weight was increased followed by a hypertrophy of the cortical tissue. a fall in adrenal cholesterol and ascorbic acid level was marked. adrenaline and noradrenaline contents of t ...19761020418
anatomical and neurohistological observations on the heart of the rose ringed parakeet, psittacula krameri.anatomy, histology and innervation of the heart of the rose ringed parakeet, psittacula krameri have been studied in the present investigation. the sinuatrial node is found to be well-developed. it is located towards the right side of the cephalic end of the interatrial septum and composed of a few nucleated cells and a large fibrous mass. the atrioventricular node is poorly defined, present at the caudal end of the interatrial septum. the node is somewhat triangular in shape and is composed of ...1976984460
histological and histochemical studies on the female reproductive system of rose-ringed parakeet (psittacula krameri) after testosterone propionate treatment.intramuscular injections of testosterone propionate (perandren, ciba) at a dose level of 2.5 mg per day for 10 days into adult female parakeet caused an increment of differentiated follicles in the ovary. the histological study of the testosterone treated oviduct of the bird showed well developed villi with a significant number of tubular glands particularly in the middle and distal parts of the oviduct. the high level of alkaline phosphatase activity and ascorbic acid concentration in the dista ...1975811044
some observations on the histochemistry of the neuropile tissue of the brain of the parrot (psittacula krameri). 19674233483
some observations on the histochemical localisation of phosphorylase in the nervous tissues of parrot (psittacula krameri). 19664161927
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