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PubMed1991

Effects of gastrin on calcium homeostasis in chickens.

As in the rat, gastrin and an extract of the acid-producing part of the stomach (proventriculus) were found to lower the blood Ca2+ concentration in the chicken. Furthermore, gastrin enhanced the uptake of 45Ca into the femur. It has been suggested previously that gastrin causes hypocalcemia in the rat by releasing gastrocalcin, a hypothetical hormone thought to reside in the acid-producing part of the stomach. The results of the present study in the chicken are in agreement with this concept. Not only exogenous, but also endogenous gastrin lowered blood calcium levels. Thus, the serum gastrin concentration was increased in response to ranitidine-evoked blockade of the gastric acid output; the rise in gastrin was associated with a transient drop in blood calcium. Also, food intake produced a rise in the serum gastrin concentration and a transient drop in blood calcium. However, injection of ranitidine or food intake in proventriclectomized (acid-producing part of the stomach extirpated) chickens failed to lower blood calcium, supporting the view that the gastrin-evoked hypocalcemia depends upon an agent in the gastric (proventriculus) mucosa. We suggest that endogenous and exogenous gastrin evoke hypocalcemia in the chicken by the same mechanism as that which has been postulated in the rat, i.e. by mobilization of the candidate hormone gastrocalcin from endocrine cells in the acid-producing gastric mucosa.

Animals↗
PubMed2005

Notch signaling functions as a binary switch for the determination of glandular and luminal fates of endodermal epithelium during chicken stomach development.

During development of the chicken proventriculus (glandular stomach), gut endoderm differentiates into glandular and luminal epithelium. We found that Delta1-expressing cells, undifferentiated cells and Notch-activated cells colocalize within the endodermal epithelium during early gland formation. Inhibition of Notch signaling using Numb or dominant-negative form of Su(H) resulted in a luminal differentiation, while forced activation of Notch signaling promoted the specification of immature glandular cells, but prevented the subsequent differentiation and the invagination of the glands. These results suggest that Delta1-mediated Notch signaling among endodermal cells functions as a binary switch for determination of glandular and luminal fates, and regulates patterned differentiation of glands in the chicken proventriculus.

Animals↗
PubMed1994

Mesenchymal regulation of epithelial gene expression in developing avian stomach: 5'-flanking region of pepsinogen gene can mediate mesenchymal influence on its expression.

The expression of a gene encoding an embryonic chick pepsinogen was investigated in developing avian gut. Expression is restricted to the epithelial layer of the embryonic proventriculus (glandular stomach). We can therefore regard this gene as a marker gene for proventricular epithelial differentiation. There is some considerable evidence in favour of epithelial-mesenchymal interactions being important during the development of the gastrointestinal system; for example, pepsinogen expression is induced in proventricular and gizzard (muscular stomach) epithelial by the proventricular mesenchyme but is suppressed by the gizzard mesenchyme. In the present paper, we studied how the mesenchymes influence this gene expression pattern. For this we produced constructs containing various portions of the 5'-flanking region of the embryonic chick pepsinogen gene, driving reporter sequences (beta-galactocidase or luciferase), and these constructs were transfected into dissociated epithelial cells either from the proventriculus or gizzard. We then recombined these cells with mesenchymal cells and cultured them as cell aggregates. In this way, we were able to dissect the timing and other requirements of the epithelial-mesenchymal interactions for expression of embryonic chick pepsinogen gene. We also report that 1.1 kb of 5'-flanking sequence is sufficient to drive correct expression of embryonic chick pepsinogen gene, although further enhancement was seen if the constructs contained 3.2 kb of upstream sequence.

Animals↗
PubMed1996

Organization of the vagal preganglionic neurons innervating the stomach in the Japanese quail (Conturinx japonica) double labeling fluorescent method.

Cytoarchitectural study indicated that the dorsal motor nucleus of the vagal nerve (nX) was formed by two subnuclei in a coronal section. One of them had large and round neurons, and occupied the dorsal part of the nX (Xd). The second one had small and oval neurons, and occupied the ventral part of the nX (Xv). The double labeling fluorescent method was performed to determine the organization of preganglionic neurons in the nX innervating different muscles of the quail stomach. Injections of nuclear yellow (NY) into the proventriculus, and of fast blue (FB) into the gizzard showed that there were no double-labeled neurons in the nX. NY- and FB-labeled neurons were found throughout the nX. After separate injections of NY and FB into both the cranioventral and caudodorsal thick muscles, and the craniodorsal and caudodorsal thin muscles, many NY- and FB-labeled neurons were distributed and intermingled in the middle two thirds of the nX. Considerable numbers of double-labeled neurons were also found at the middle level of the nX. There was no side-predominancy of the population of the preganglionic neurons innervating the quail stomach. These results show that, many neurons of both sides of the nX are separately innervating both the proventriculus and gizzard, and considerable numbers of single neurons of the nX also innervate a pair of thin or thick muscles with collateral axons.

Amidines↗
PubMed2005

Systemic spindle-cell proliferative disease in broiler chickens.

The major organs and tissues of 24 broiler chickens (70 or 71 days old) suspected of spindle-cell proliferative disease (SPD) because of showing the tumorous lesions distributed throughout the body at meat inspection were collected for histopathological and immunohistochemical examination. Macroscopically, liver, spleen and cecal tonsil showed severe enlargement and white nodules or plaques were observed in the liver, spleen, kidney, intestine and bone marrow of the femur. All chickens were diagnosed with SPD based on the histopathological examination. The lesions of SPD were observed in the liver, spleen, kidney, heart, lung, pancreas, proventriculus, gizzard, duodenum, jejunum, ileum, rectum, cecal tonsil, bursa of Fabricius, bone marrow of the femur and skin. Hemangioma was observed in the lung of 1 bird. Eight 1-day-old specific pathogen-free chicks were inoculated intraperitoneally with 0.25 ml of a 20% homogenate of the affected spleens of three naturally occurring cases. One inoculated bird, necropsied at 10 weeks of age, macroscopically had a white nodule in the kidney and histopathologically had spindle-cell proliferative lesions, a pattern similar to that seen in the naturally occurring cases, in the liver, spleen, kidney, heart, lung, pancreas, proventriculus, duodenum, cecal tonsil and bone marrow of the femur, and was diagnosed with SPD. Immunohistochemically, significant positive reactions with a rabbit antiserum against avian leukosis virus antigens were detected in all spindle cells in the proliferative lesions of all examined SPD cases and in tumor cells of the hemangioma of a field case.

Animals↗
PubMedDate not supplied

Extrapituitary TSH in early chick embryos: Pit-1 dependence?

The expression of the thyrotropin (TSH) gene in the pituitary gland is thought to be dependent upon the pituitary-specific transcription factor, Pit-1. TSH immunoreactivity is, however, widespread in extrapituitary tissues, and the possibility that this may reflect a widespread distribution of Pit-1 was therefore investigated in embryonic chicks, prior to the ontogenic differentiation of the pituitary gland. TSH immunoreactivity in chick embryos at the end of the first trimester of the 21d incubation period was present in discrete cells in the developing brain (particularly in ependymal cells lining the diocoele and mesocoele and in cells lining the otic vesicle), spinal cord (ependymal cells), liver (hepatocytes), lungs (in the linings of the bronchi), gut (in the linings of the proventriculus) and limb bud (in skin, muscle, bone and nerve fibers). In some of these tissues (particularly in brain and spinal cord ependymal cells, cells in the otic vesicle and in liver hepatocytes), the distribution of TSH immunoreactivity was overlapped by the distribution of immunoreactive Pit-1, suggesting Pit-1 involvement in TSH expression in these sites. However, in other tissues (e.g., the trigeminal nerve in the head and the marginal mantle layer of the spinal cord), Pit-1 immunoreactivity was intense but TSH immunoreactivity was marginal. Conversely, other tissues (e.g., cells in the skin, blood vessels, limb bud, bronchus, proventriculus, and cardiopleural cavities) had intense TSH staining but little, if any, Pit-1 immunoreactivity. The expression of the TSH gene in these tissues would thus appear to be Pit-1 independent. These results demonstrate the presence of Pit-1 in pituitary and extrapituitary tissues of the domes tic fowl and suggest the involvement of Pit-1 in the extrapituitary expression of TSH in chick embryos may be tissue-specific.

Abdomen↗
PubMedDate not supplied

interactions between escherichia coli and Newcastle disease virus in chickens.

We investigated the interaction between Newcastle disease virus (NDV) and Escherichia coli in cell cultures, embryonated eggs, and 8-wk-old chickens. We measured the interactions on the basis of bacterial adherence and NDV hemagglutination titer in chickens, chicken embryos, and chicken embryo cell culture. Depending on the inoculation order of E. coli, a significant alteration of the growth of NDV was observed in both chickens and chicken embryos. When certain strains of E. coli were given before NDV exposure, the virus titers were lowered. In chickens, the mean virus titer was significantly (P < 0.05) lowered in the crop, the proventriculus, the gizzard, and the jejunum. However, there were no significant differences (P < 0.05) between the two groups for NDV titers in the duodenum, ileum, and cecum. In chicken embryos, when E. coli serotypes O78 and O119:B14 were inoculated before NDV exposure, the mean NDV titers were significantly (P < 0.5) lowered. However, there were no significant differences (P < 0.05) in NDV titer between the two groups when E. coli serotypes O78:K80:NM and O1ab:K NM were inoculated 24 hr before NDV exposure. When NDV was given prior to E. coli exposure, NDV titer was higher in both chickens and chicken embryos. In chickens, when NDV was given 48 hr before E. coli inoculation, NDV was detected in the proventriculus, gizzard, jejunum, ileum, and cecum, whereas no virus was detected in the control groups (NDV only). In the crop, NDV was detected at a significantly (P < 0.05) higher titer in the E. coli-inoculated group when compared with the control group that received NDV alone. In chicken embryos, virus titer was significantly (P < 0.05) higher when NDV was given 24 hr before E. coli inoculation for all three NDV strains used (Ulster and V4 strains). Adherence of E. coli to chicken embryo kidney (CEK) cells was significantly higher (P < 0.05) when the CEK cells were infected first with NDV and then by E. coli. The mean bacterial count per microscopic field in NDV-uninfected monolayers was eight compared with 112 for the NDV-infected monolayers. In approximately 10% of the fields in NDV-infected monolayers, the bacteria were too numerous to count.

Animals↗
PubMed2007

The regulation of stearoyl-CoA desaturase gene expression is tissue specific in chickens.

Emerging evidence suggests a potential role of stearoyl-CoA desaturase (SCD)-1 in the control of body weight and energy homeostasis. The present study was conducted to investigate the effects of several energy balance-related factors (leptin, cerulenin, food deprivation, genotype, and gender) on SCD gene expression in chickens. In experiment 1, 6-week-old female and male broiler chickens were used. In experiment 2, two groups of 3-week-old broiler chickens were continuously infused with recombinant chicken leptin (8 micro g/kg/h) or vehicle for 6 h. In experiment 3, two groups of 2-week-old broiler chickens received i.v. injections of cerulenin (15 mg/kg) or vehicle. In experiment 4, two broiler chicken lines (fat and lean) were submitted to two nutritional states (food deprivation for 16 or 24 h and feeding ad libitum). At the end of each experiment, tissues were collected for analyzing SCD gene expression. Data from experiment 1 showed that SCD is ubiquitously expressed in chicken tissues with highest levels in the proventriculus followed by the ovary, hypothalamus, kidney, liver, and adipose tissue in female, and hypothalamus, leg muscle, pancreas, liver, and adipose tissue in male. Female chickens exhibited significantly higher SCD mRNA levels in kidney, breast muscle, proventriculus, and intestine than male chickens. However, hypothalamic SCD gene expression was higher in male than in female (P < 0.05). Leptin increased SCD gene expression in chicken liver (P < 0.05), whereas cerulenin decreased SCD mRNA levels in muscle. Both leptin and cerulenin significantly reduced food intake (P < 0.05). Food deprivation for either 16 or 24 h decreased the hepatic SCD gene expression in fat line and lean line chickens compared with their fed counterparts (P < 0.05). The hypothalamic SCD mRNA levels were decreased in both lines only after 24 h of food deprivation (P < 0.05). In conclusion, SCD is ubiquitously expressed in chickens and it is regulated by leptin, cerulenin, nutritional state, and gender in a tissue-specific manner.

Adipose Tissue↗
PubMed1981

Avian gout caused by oosporein, a mycotoxin produced by Caetomium trilaterale.

In a series of four experiments, diets containing oosporein at graded concentrations from 0 to 600 microgram/g were fed to male broiler chicks from hatching to 3 weeks of age. At dietary toxin levels of 100 microgram/g and below, no detrimental effects were observed. Dietary oosporein concentrations of 200 microgram/g and above elicited dose-related mortality resulting from severe visceral and articular gout. Three-week cumulative mortality percentages were 0, 13, 30, 57, and 95% for the 0, 200, 300, 400, and 600 microgram/g levels, respectively. Upon necropsy, the prominent lesions observed were massive urate deposits in various tissues, swollen and pale kidneys, dehydration, proventricular enlargement with mucosal necrosis, and a green discoloration of the gizzard lining. The effects on the proventriculus and gizzard occurred at doses as low as 200 microgram/g and were the most sensitive indicators of oosporein-toxicosis. In addition to the proventriculus, the relative weights of the kidney and liver were significantly increased in a dose-related fashion. A significant reduction in 3-week body weight at 400 microgram/g apparently resulted from the lower feed consumption concomitantly observed at this level of dietary toxin. Oosporein also caused an increase in water consumption at 400 and 600 microgram/g. Blood analyses indicated no toxin-related effect on plasma glucose, plasma protein, packed red blood cell volume, hemoglobin, and prothrombin times. The plasma concentration of uric acid was significantly elevated at 400 microgram/g. These data and mechanistic considerations suggest that oosporein should be classified as a nephrotoxin in the broiler chicken.

Animals↗
PubMed1984

Influence of dietary electrolytes on digestive tract pH and acid-base status of chicks.

The nutritional interaction of lysine and arginine is affected by the electrolyte balance of the diet. Because the ionization and, therefore, the transport and metabolism of these amino acids may be affected by the pH of fluids in which they are dissolved, the present study was conducted to determine the effect of dietary electrolytes on the pH of the digestive tract and the acid-base status of the chicken. A purified casein diet deficient in arginine was modified by addition of either KHCO3 or CaCl2 X 2H2O at levels sufficient either to alleviate or to exacerbate the lysine-arginine antagonism. Addition of KHCO3 led to a more alkaline diet than the arginine-deficient control while CaCl2 X 2H2O resulted in a more acidic diet. Varying the electrolyte balance had little effect on digestive tract pH. The pH of the crop was depressed (P less than .05) by dietary Cl-, but neither Cl- nor K+ had an effect on the pH of the proventriculus, duodenum, or middle and distal portions of the small intestine (P greater than .05). Dietary Cl- significantly depressed plasma bicarbonate, base excess, and PCO2 (P less than .05) but did not significantly decrease plasma pH (P greater than .05). These same acid-base parameters were unaffected by addition of K+ to the control diet. It is concluded that variations in dietary electrolytes affect the acid-base balance of the chicken and alter the pH of the crop. However, the pH of the digestive tract from the proventriculus to the distal small intestine is unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1988

Influence of ochratoxin A and deoxynivalenol on growing broiler chicks.

The effects of feeding diets containing ochratoxin A (OA) (2.0 mg/kg) and deoxynivalenol (DON) (16 mg/kg) singly and in combination were characterized in male broiler chicks from 1 to 3 wk of age. Body weight gains and efficiency of feed utilization were significantly reduced by feeding OA singly, DON singly, and the OA/DON combination. Increased relative liver, kidney, and proventriculus weights were observed in the OA and OA-DON groups and blood urea nitrogen (BUN) was increased in the DON group. Serum uric acid, creatinine, and triglycerides were significantly elevated, and total protein, albumin, cholesterol, and aspartate amino transferase (AST) activity were decreased in the OA group. Histopathological examination of the liver, kidney, spleen, proventriculus, gizzard, and bursa revealed that lesions were confined primarily to mild hepatocellular degeneration, with milk diffuse lipidosis of the liver and mild swelling of the renal tubular epithelium of the OA and OA/DON combination groups. For a few parameters such as efficiency of utilization and relative liver, gizzard, and spleen weights. OA and DON appear to interact additively. However, many of the parameters such as body weights, body weight gains, BUN, total protein, and AST show significant interactions that can best be described as less than additive or in some cases antagonistic.

Animals↗
PubMed1989

Digestive tract clearance of broilers cooped or deprived of water.

Feed is withdrawn from broilers to facilitate digestive tract clearance before processing. This research examined the effects of cooping and water deprivation on contents of the digestive tract during feed withdrawal in two experiments. Broilers were reared to 48 days of age on litter in a windowless house. Corn-soybean meal diets and water were provided ad libitum. In the first experiment, broilers were continuously fed before feed withdrawal. In the second experiment, broilers were placed on a meal-feeding regimen of 1.5 h on feed and 4.5 h off feed for 42 h prior to feed withdrawal. Withdrawal began at the end of a 1.5-h feeding period. At the time of feed withdrawal, broilers were cooped, left on litter without water, or left on litter with water available. At 2, 4, 6, and 8 h after withdrawal, ten broilers from each treatment were killed and the crop, proventriculus plus gizzard, and small intestine were removed. The weight of the contents of each segment was determined. Water deprivation did not change the weight of contents in any segment. Cooped broilers retained digesta in the crop and proventriculus plus gizzard for a longer time than broilers on litter. The combination of meal feeding and cooping soon after feed withdrawal greatly increased the quantity of digesta in the crop 8 h after feed withdrawal. Cooping should be delayed until the crop is empty. Meal feeding increases the time required to accomplish this.

Animals↗
PubMed1993

The use of Saccharomyces cerevisiae to suppress the effects of aflatoxicosis in broiler chicks.

Three hundred and sixty day-old commercial broiler chicks were assigned to a 3 x 2 factorial arrangement of treatments to examine the effects of three levels of Saccharomyces cerevisiae 0, .05, and .1% of feed, and two levels of aflatoxin, 0 and 5 ppm, singly and in combination on aflatoxicosis. Each treatment group was replicated three times. The S. cerevisiae and aflatoxin were incorporated in a standard commercial broiler ration and fed to chicks for 4 wk. Data were collected weekly on body weights, and at the end of the experiment on the relative weights of the liver, proventriculus, pancreas, and heart. Serum concentrations of the albumin, total protein, cholesterol, uric acid, triglycerides, and enzyme activities of alanine transaminase, aspartate aminotransferase, lactase dehydrogenase, and creatine phosphokinase were also evaluated. Results showed that chicks receiving aflatoxin-contaminated feed had suppressed body weight (456 g), which significantly improved (516 g) with the inclusion of .1% S. cerevisiae. The relative weights of liver (3.58%), heart (.916%), and proventriculus (.770%), which increased significantly with the addition of 5 ppm of aflatoxin, were restored to 3.00, .783, and .680%, respectively, with the dietary inclusion of .1% S. cerevisiae. The serum concentrations of albumin and total protein (.66 and 1.62 g/100 mL), which were significantly decreased by aflatoxin, were elevated to .88 and 2.24 g/100 mL, respectively, with the inclusion of .1% S. cerevisiae.(ABSTRACT TRUNCATED AT 250 WORDS)

Aflatoxins↗
PubMed1995

Effect of early nutrient restriction on broiler chickens. 1. Performance and development of the gastrointestinal tract.

An experiment was conducted to determine the effects of early nutrient restriction on performance and development of the gastrointestinal tract of broiler chickens. Four hundred male broiler (Ross x Ross) chicks raised in floor pens were assigned to two treatment groups. One group was given ad libitum access to feed from 1 to 48 d of age. The second group was feed restricted from 7 to 14 d of age to an energy intake of 1.5 x BW.67 kcal ME/d and then given ad libitum access to feed from 14 to 48 d. Body weight and feed intake were determined weekly. At 49 d of age, birds were processed for carcass yield, abdominal fat pad measurement, and body composition analysis. Broilers were also sampled at 7, 14, 21, and 41 d of age for proventriculus, gizzard, small intestine (duodenum, jejunum, and ileum), pancreas, and liver weights and for intestinal length measurements. Total DNA, protein:DNA, and RNA:DNA ratios of livers and jejuna were determined as indexes of changes in cell size and number. Feed-restricted broilers failed to catch up to the Control birds in BW at 48 d of age but were superior (P < .01) in overall feed efficiency. No treatment effects were observed on breast meat yields or abdominal fat. Moreover, percentage carcass fat, crude protein, ash, and dry matter were not affected by restricted feeding. Body weight and weights of gastrointestinal organs were reduced (P < .01) by feed restriction at 14 d of age. Restricted feeding, however, did not decrease the relative weights of organs, except for liver. Feed restriction also resulted in a reduction (P < .01) of liver cell number and size and a decrease in jejunum cell number. All organs recovered normal weight on refeeding, and all cellular constituent ratios (e.g., RNA:DNA, RNA:protein, and protein:DNA) returned to normal by 41 d of age. Absolute and relative weights of supply organs (e.g., proventriculus, gizzard, small intestine, liver, and pancreas) were less affected by feed restriction and responded more quickly to refeeding than the whole body.

Animal Nutritional Physiological Phenomena↗
PubMed2001

Pathogenic and pathological characteristic of new type gosling viral enteritis first observed in China.

AIM: To study the purifying method and characteristics of new gosling viral enteritis virus (NGVEV),the etiological agent of new gosling viral enteritis (NGVE) which was first recognized in China, as well as the pathomorphological development in goslings infected artificially with NGVEV. METHODS: (1)NGVEV virions were purified by the procedure of treatment with chloroform and ammonium sulfate precipitation, dialysis to remove the sulfate radical and ammonium ion and separation by gel filtration chromatography, and SDS-PAGE. (2)Forty-2-day-old White Sichuan goslings were orally administered with NGVEV and 24 hr later 2 birds were randomly selected and killed at 24hr intervals until death occurred. Specimens(duodenum, ileum, liver, heart, kidney, spleen, lung, proventriculus, pancreas, esophagus, and the intestinal embolus) were taken until all birds in this group died and were sectioned and stained with hemotoxylin and eosin and studied by light microscope. RESULTS: NGVEV shared the typical characteristics of Adenovirus and which structural proteins consisted of 15 polypeptides. Necrosis and sloughing of the epithelial cells covering the villus tips of the duodenum were first observed in goslings 2 days postinfection artificially with NGVEV. With the progress of infection, this lesion rapidly occurred in the epithelium at the base of the villus and with infiltration of the inflammatory cells, the jejunum tended to be involved. With the intensification of mucosa necrosis and inflammatory exudation of the small intestine, fibrinonecrotic enteritis was further developed and embolus composed of either intestinal contents wrapped by pseudo-membrane or of the mixture of fibrous exudate and necrotic intestinal mucosa were observed in the middle-lower part of the small intestine. This structure occluded the intestinal tract and made the intestine dilated in appearance. The intestinal glandular cells underwent degeneration, necrosis and might be found sloughed into the lumen. Hemorrhage and hyperemia could be observed on the lung and kidney. Epithelial cells of the renal tubular underwent degeneration. In some cases, granular degeneration and fatty degeneration could be found in the liver and in some cases at a later stage of this disease the epithelial cells of trachea and proventriculus might be found sloughed. In some cases at an early stage of this disease, cardiac hyperemia and hemorrhage could be observed. Esophagus, pancreas and brain were found normal. Analyses and comparisons between the pathologic lesions of NGVE and Gosling Plague (GP) were available in this paper as well. CONCLUSION: (1)NGVEV is adenovirus. (2)Pathological characteristic could be as the data for NGVE diagnosis.

Adenoviridae↗
PubMed1984

Epizootiology, development, and pathology of Geopetitia aspiculata Webster, 1971 (Nematoda: Habronematoidea) in tropical birds at the Assiniboine Park Zoo, Winnipeg, Canada.

Geopetitia aspiculata was found in 12 species of Passeriformes, one species of Coraciiformes, and one species of Charadriiformes which died in a free-flight area in the Tropical House at the Assiniboine Park Zoo, Winnipeg, Canada. The nematodes occurred in chronic inflammatory cysts attached to the serosa of the posterior end of the esophagus, proventriculus, and the anterior part of the gizzard. Posterior ends of worms were observed to extend from the cyst into the lumen of the proventriculus. Birds hatched and raised in the Tropical House acquired infections, probably through the agency of feral crickets. Experimental studies showed that G. aspiculata developed to the infective third stage in the fat body of Acheta domesticus (L.). This is the first transmission cycle of Geopetitia spp. to be elucidated and the egg, first, third, and early fifth stages of the parasite are described. The absence of spicules in males of G. aspiculata is confirmed. Geopetitia aspiculata was probably introduced to the Zoo by infected tropical birds obtained from dealers or other zoos. The wild source of the parasite is not known since G. aspiculata has never been reported in wild birds; the report of G. aspiculata in wild Piciformes in Cuba by Barus (1971) is in error.

Animals↗
PubMed1975

[The effect of N-nitrosomethylurea on organ cultures of human embryonal lung tissue].

The character of blastomogenic action of 7,12-dimethylbenz(a)anthracene on the stomach in its parenteral administration was studied on different lines of mice. Under the same conditions DMBA distribution was investigated in the proventriculus and gastric glandular tissues. In DMBA application on mice skin in the dosage of 0.5 mg per animal in 0.1 ml of acetone proventricular tumors developed in 34% of mice of line CC57Br, in 10% of mice of line CC57W, and in 11% of mice of line C3HA, and in 19% of white nonpedigree mice. In intraperitoneal injection of DMBA in the dose of 0.5 mg per mouse in 0.2 ml of saline solution proventricular tumors appeared in 56% of CC57Br mice (in 9 of 16) and in one of five mice of CC57W line. Whereas, in application of DMBA onto mice skin in the dose of 0.5 mg per mouse in 0.1 ml of acetone the DMBA content in the proventriculus was 13 times higher than that in gastric glandular tissues.

Female↗
PubMedDate not supplied

[Relationship of the flea Citellophilus tesquorum altaicus (Siphonaptera: Ceratophyllidae) with the plague agent].

Some aspects of relationships of the flea Citellophilus tesquorum altaicus and bacterium Yersinia pestis of two strains isolated from different parts of the Tuva natural plague focus were studied. Peculiarities of elimination and blood meal activity of fleas infected with two strains of the plague agent were not revealed. Differences in mortality and alimentary activity are considerably determined by the sex of insects. The ability of examined strains to form a proventriculus block was not identical in the strains examined. This ability was expressed higher in the strain I-3428, which originated from the same part of the natural focus as the insectarium flea culture, than in the strain I-3327. During the spring and first half of summer, the proventriculus block appeared more frequently in females. The increasing of the fraction of blocked individuals was observed in both sexes from spring to summer. As for the ability to transmit the plague agent, similar seasonal increasing was noted in males, but in females, the ability to inoculate the plague microbe was always maintained at the same level.

Animals↗