Occurrence of oxyphil cells in suppressed parathyroid glands

Parathyroid glands from Mongolian gerbils cultured for 7 days at a high calcium concentration and examined by electron microscopy, were found to contain suppressed chief cells containing numerous mitochondria, and some oxyphil cells containing an abundance of medium-sized or large mitochondria with calcium-containing precipitates. It is suggested that parathyroid chief cells may be transformed into oxyphil cells, under certain conditions, and that the associated increase in the number and size of the mitochondria may be related to an intracellular accumulation of calcium.     

Experimental study of the origin of the parathyroid glands.

The origin of the parathyroid glands was investigated in chick embryos (Gallus domesticus). Pieces of the third branchial arch were grafted, and its ectodermal layer formed a new structure (parathyroid III), which became separated from the placodial ectoderm. This structure continued to develop until, together with neural crest cells which gave rise to the mesenchyme, it formed a distinct parathyroid III gland by stage 28 of Hamburger and Hamilton.     

Helicobacter pylori-associated gastric pro- and antioxidant formation in Mongolian gerbils

Helicobacter pylori colonized gastric mucosa is manifest in a significant neutrophil infiltration with an extensive level of oxyradical formation. Mongolian gerbil is one of the excellent models for H. pylori-infection. The present study was designed to investigate pro- and antioxidant formation in the stomach of H. pylori-positive gerbils. Fourteen male Mongolian gerbils (MGS/Sea) were orally inoculated with H. pylori (ATCC43504) (Hp group) and 15 gerbils were inoculated with the culture media (Control). H. pylori infection was confirmed by the serum anti-H. pylori IgG test. Each gerbil was evaluated 6 or 12 weeks after the inoculation. Neutrophil infiltration was assessed by the tissue MPO activity. Mucosal oxidative stress was evaluated by thiobarbituric acid-reactive substances (TBARS), total glutathione contents, glutathione peroxidase (GSHPx) activity and Cu-, Zn-superoxide dismutase (SOD) activity. In Hp group, the H. pylori was persistently infected until 12 weeks. The level of MPO activity was significantly higher in Hp group at 6 and 12 weeks. Although the levels of TBARS and total glutathione were within the same range as controls at 6 weeks, they were significantly increased at 12 weeks. However, GSHPx activity was significantly increased at 6 weeks, but became the same range with the controls at 12 weeks. SOD activity showed no significant increase in Hp group at 6 and 12 weeks. In conclusion, H. pylori inoculation induced gastric mucosal neutrophil activation and pro-oxidant formation and also increased total glutathione contents, one of the mucosal antioxidants in gerbils.     

Propagation of nephropathia epidemica virus in Mongolian gerbils.

Nephropathia epidemica virus, the etiological agent of hemorrhagic fever with renal syndrome in Scandinavia, was serially propagated in Mongolian gerbils (Meriones unguiculatus). Intracerebrally inoculated suckling gerbils developed subclinical infections, with viral antigen found in lung, brain, liver and spleen. The distribution of viral antigen was similar to that seen in experimentally infected bank voles (Clethrionomys glareolus), the principal wild rodent reservoir of nephropathia epidemica virus. This model provides a readily available animal host for the study of experimental nephropathia epidemica virus infection.     

A proteomic approach to study parathyroid glands

Parathyroid tumours are heterogeneous and in some cases the diagnosis may be difficult using histological features. In this study we used a two-dimensional electrophoresis (2D)/mass spectrometry (MS)-based approach to examine the global changes of parathyroid adenoma tissues protein profile compared to the parathyroid normal tissues. Validation of protein expression was performed by immunoblotting using specific antibodies. Ingenuity software was used to identify the biological processes to which these proteins belong and to construct a potential network. A total of 30 proteins were found to be differentially expressed, of which 22 resulted in being over-expressed. Proteins identified by 2D/MS/MS proteomics were classified into functional categories and a major change (≥ 2-fold) in terms of expression was found in proteins involved in response to biotic stimuli, cell organization and signal transduction. After Ingenuity analysis, 14-3-3 ζ/δ appears to be a key protein in the network of parathyroid adenoma, where it is linked to other proteins such as annexin A2, B box and SPRY domain-containing protein (BSPRY), p53 and epidermal growth factor receptor (EGFR). Our results suggest that the proteomic approach was able to differentiate the protein profiles of normal parathyroid and parathyroid adenoma and identify a panel of proteins which are differentially expressed. The functional role of these proteins in the network of intracellular pathways is discussed.     

Histochemical study on the bile duct system of normal Mongolian gerbils

The bile duct system of normal Mongolian gerbils was examined histochemically. The luminal surface membrane and apical cytoplasm of the biliary and gallbladder epithelial cells were stained with periodic acid-Schiff (PAS), alcian blue, pH 2.5 (AB) and high iron diamine (HID)-AB, and many epithelial cells of the common bile duct and gallbladder had weakly PAS-positive granular material in their supranuclear cytoplasm. Lectin-histochemically, these cells had binding sites to Concanavalia ensiformis (ConA), Dolichos biflorus (DBA), Glycine max (SBA), Ulex europeas-I (UEA-I), and Triticum vulgaris (WGA). On the other hand, the periductal glandular epithelial cells were not stained by any histochemical stainings. In addition to these light microscopic findings, the electron microscopic findings based on the periodic acid-silver methenamine method and avidin-biotin colloidal gold method for DBA and WGA suggested that the biliary and gallbladder epithelial cells of Mongolian gerbils secreted mucin with terminal sialic and sulfonic acid residues and that the lectin binding activity of mucin secreted from these cells was similar to that of mucin secreted from the periductal glandular epithelial cells of mice and rats.     

Effects of aspirin on the development of Helicobacter pylori-induced gastric inflammation and heterotopic proliferative glands in Mongolian gerbils

Background: Helicobacter pylori infection is a major cause of gastritis and gastric carcinoma. Aspirin has anti‐inflammatory and antineoplastic activity. The aim of the present study was to determine the effects of aspirin on H. pylori‐induced gastritis and the development of heterotopic proliferative glands. Methods: H. pylori strain SS1 was inoculated into the stomachs of Mongolian gerbils. Two weeks after inoculation, the animals were fed with the powder diets containing 0 p.p.m. (n = 10), 150 p.p.m. (n = 10), or 500 p.p.m. (n = 10) aspirin. Mongolian gerbils were killed after 36 weeks of infection. Uninfected Mongolian gerbils (n = 10) were used as controls. Histologic changes, epithelial cell proliferation and apoptosis, and prostaglandin E₂ (PGE₂) levels of gastric tissue were determined. Results: H. pylori infection induced gastric inflammation. Administration of aspirin did not change H. pylori‐induced gastritis, but alleviated H. pylori‐induced hyperplasia and the development of heterotopic proliferative glands. Administration of aspirin accelerated H. pylori‐associated apoptosis but decreased H. pylori‐associated cell proliferation. In addition, the increased gastric PGE₂ levels due to H. pylori infection were suppressed by treatment with aspirin, especially at the dose of 500 p.p.m. Conclusions: Aspirin alleviates H. pylori‐induced hyperplasia and the development of heterotopic proliferative glands. Moreover, aspirin increases H. pylori‐induced apoptosis. We demonstrated the antineoplastic activities of aspirin in H. pylori‐related gastric carcinogenesis.     

Genetic consequences of group living in Mongolian gerbils

Social behavior can shape the local population genetic structure of mammals. Group living can increase pairwise genetic relatedness of mammals at a local level but differentiate the genetic structure at a population level through offspring philopatry and nonrandom mating. Our study aimed to test the hypothesis that social groups of Mongolian gerbils (Meriones unguiculatus) would consist of genetically related individuals due to offspring philopatry and would have distinct genetic structures because of restricted gene flow among social groups and nonrandom mating. We genotyped 327 wild gerbils, live captured from 28 social groups in Inner Mongolia, China, using nine microsatellite loci. The within-group pairwise genetic relatedness coefficient averaged 0.28 ± 0.14 (standard deviation), whereas the average pairwise genetic relatedness coefficient of the whole gerbil population was 0.0 ± 0.2. Additionally, the value of the global F statistic (F(st)) was 0.21, suggesting a substantial genetic differentiation among social groups of Mongolian gerbils. The Bayesian clustering divided the 327 gerbils into 23 distinct genetic clusters. Therefore, our results show that high within-group genetic relatedness and among-group genetic differentiation are the genetic consequences of group living in social mammals because of restricted gene flow, female philopatry, and nonrandom mating within social groups.     

Cholecalciferol metabolites binding in porcine parathyroid glands.

We studied the cytoplasmic and nuclear binding of 25-hydroxychole-calciferol and 1alpha,25-dihydroxycholecalciferol inside porcine parathyroid glands. Both sterols bind to cytoplasmic components, but a specific nuclear uptake was demonstrated only for 1alpha,25-dihydroxycholecalciferol. These findings support the hypothesis that mammalian parathyroid glands are a target organ for some cholecalciferol metabolites.     

Cryosurgery of parathyroid glands

The effectiveness of cryosurgery in destruction of parathyroid glands in rats was studied by comparison of 4 experimental groups: 1. cryosurgery utilizing 3 patterns of repetitive freezing, 2. excision, 3. sham operation, or 4. no treatment. Evaluation included clinical observation of respirations and voice, serum calcium concentration, and histologic examination of parathyroid tissue. The results indicate that the extent of destruction of parathyroid glands in rats can be controlled by specific cryosurgical techniques without thyroidectomy or risk of permanent injury to the recurrent laryngeal nerves.     

Role of Helicobacter pylori in gastric carcinogenesis: the origin of gastric cancers and heterotopic proliferative glands in Mongolian gerbils

Helicobacter pylori infection is well accepted to be a very important factor for the development of gastric carcinogenesis in the human stomach. In Mongolian gerbils treated with chemical carcinogens, H. pylori infection enhances glandular stomach carcinogenesis, and eradication of infection and results in curtailment of enhancing effects, particularly at early stages of associated inflammation. A high-salt diet exacerbates the effects of H. pylori infection on gastric carcinogenesis, and these two factors act synergistically to promote the development of gastric cancers in this animal model. However, the bacterium exerts the greater effects. Early acquisition significantly increases gastric chemical carcinogenesis in Mongolian gerbils, as compared to later infection. While heterotopic proliferative glands, hyperplastic and dilated glands localized beneath the muscularis mucosae, frequently develop with H. pylori infection alone in this animal model, they obviously regress on eradication, suggesting a relation to severe gastritis, rather than a malignant character. Furthermore, endocrine cells, positive for chromogranin A, are observed in the heterotopic proliferative glands, in contrast to cancerous lesions which lack endocrine elements. In conclusion, H. pylori is not an initiator, but rather a strong promoter of gastric carcinogenesis, whose eradication, together with reduction in salt intake, might effectively prevent gastric cancer development.     

Polaprezinc attenuates Helicobacter pylori-associated gastritis in Mongolian gerbils

Background. The ammonia‐monochloramine system plays an important role in Helicobacter pylori‐associated gastric mucosal injury. Polaprezinc, a new antiulcer agent, has a scavenging action against monochloramine. The aim of the experiment was to investigate the inhibitory effects of polaprezinc on the H. pylori‐induced gastritis in Mongolian gerbils. Materials and Methods. Mongolian gerbils fasting for 24 hours were orally given culture broth containing 2–4 × 10⁸ colony‐forming units of H. pylori ATCC 43054 per milliliter. From 4 hours after inoculation until the end of the experiment, gerbils were given chow pellets with or without 0.02% polaprezinc. All gerbils were killed 12 weeks later. The grades of H. pylori density and histologic features of gastritis were evaluated in accordance with the Updated Sydney System. The scavenging effect of polaprezinc on monochloramine was investigated spectrophotometrically. Results. Polaprezinc had little or no influence on the H. pylori density in both pyloric and fundic mucosae. However, it significantly attenuated the development of polymorphonuclear neutrophil activity, mononuclear infiltration, and surface epithelial erosion in both pyloric and fundic mucosae compared with those of the control group. H. pylori inoculation significantly increased the heights of both pyloric and fundic mucosae (mainly due to the increased height of foveolar hyperplasia), but polaprezinc inhibited the increase of mucosal thickness in both pyloric and fundic mucasae. No intestinal metaplasia was detected in this study. Spectrophotometric examination revealed that polaprezinc scavenged monochloramine. Conclusions. Polaprezinc inhibited the development of H. pylori‐induced gastritis through its scavenging action against monochloramine.     

Immunocytochemical localization of parathyroid hormone in rabbit parathyroid glands

Immunocytochemical localization of parathyroid hormone was examined in the rabbit parathyroid gland by means of protein A-gold technique. Protein A-gold particles were observed on the secretory granules and the large secretory granules thought to be storage granules. No protein A-gold particles were observed on cisternae of the endoplasmic reticulum and the Golgi apparatus.     

Anti-Thy-1 monoclonal antibody-induced glomerulonephritis in Mongolian gerbils

Two novel murine monoclonal antibodies (mAbs) were produced to the Thy-1 molecule of Mongolian gerbils (Meriones unguiculatus). These mAbs, HUSM-M.g.27 of IgG1 isotype and HUSM-M.g.40 of IgG2a isotype, immunohistochemically reacted with the thymus, nervous system, and glomerular mesangium in partially different manners, suggesting that they recognize distinct epitopes, although they reacted with Thy-1 antigen, with apparent molecular weight of about 25 kDa, on gerbil thymocytes. Mild and severe forms of mesangioproliferative nephritis after glomerular deposition of the antibody was observed in gerbils administered mAbs HUSM-M.g.27 and HUSM-M.g.40, respectively, intraperitoneally, with or without guinea-pig serum as supplementary complement. Distinct pathogenicity and requirement of guinea pig serum for pathologic sequels are discussed as they relate to the rat model of anti-Thy-1-induced glomerulonephritis.     

长爪沙鼠和布氏田鼠汗腺的分布与密度

哺乳动物受到高温胁迫时可通过分泌汗液调节体温。一般认为啮齿类在高温时不出汗,但有关野生啮齿类汗腺的资料不多。我们以长爪沙鼠和布氏田鼠为研究对象,采用苏木精—伊红染色方法,观察了身体各部位皮肤的形态学特征、汗腺的分布和密度。结果显示:(1)两种鼠的头部、口角、胸部、腋窝、腹部、背部和后腿部的皮肤都无汗腺分布,只在不被毛的前足与被毛的后足有外泌汗腺分布;(2)长爪沙鼠前、后足皮肤汗腺的密度分别为(2.40±0.49)个/mm2和(0.15±0.03)个/mm2,前足显著多于后足;布氏田鼠前、后足皮肤汗腺的密度分别为(0.37±0.05)个/mm2和(0.21±0.08)个/mm2,前、后足无显著差异。两种鼠前后足皮肤的汗腺密度可能与被毛状态相关,有被毛则汗腺密度低。推测长爪沙鼠和布氏田鼠前后足的汗腺可能具有辅助散热和运动时增加摩擦力等功能。     

Cecal microbial transplantation attenuates hyperthyroid-induced thermogenesis in Mongolian gerbils

Endothermic mammals have a high energy cost to maintain a stable and high body temperature (T_b, around 37°C). Thyroid hormones are a major regulator for energy metabolism and T_b. The gut microbiota is involved in modulating host energy metabolism. However, whether the interaction between the gut microbiota and thyroid hormones is involved in metabolic and thermal regulations is unclear. We hypothesized that thyroid hormones via an interaction with gut microbiota orchestrate host thermogenesis and T_b. l -thyroxine-induced hyperthyroid Mongolian gerbils (Meriones unguiculatus) increased resting metabolic rate (RMR) and T_b, whereas Methimazole-induced hypothyroid animals decreased RMR. Both hypothyroid and hyperthyroid animals differed significantly in faecal bacterial community. Hyperthyroidism increased the relative abundance of pathogenic bacteria, such as Helicobacter and Rikenella, and decreased abundance of beneficial bacteria Butyricimonas and Parabacteroides, accompanied by reduced total bile acids and short-chain fatty acids. Furthermore, the hyperthyroid gerbils transplanted with the microbiota from control donors increased type 2 deiodinase (DIO2) expression in the liver and showed a greater rate of decline of both serum T3 and T4 levels and, consequently, a more rapid recovery of normal RMR and T_b. These findings indicate that thyroid hormones regulate thermogenesis depending on gut microbiota and colonization with normal microbiota by caecal microbial transplantation attenuates hyperthyroid-induced thermogenesis. This work reveals the functional consequences of the gut microbiota-thyroid axis in controlling host metabolic physiology and T_b in endotherms.     

Echinococcus multilocularis: responses to infection in Mongolian gerbils

Mongolian gerbils (Meriones unguiculatus) inoculated intraperitoneally with three acephalic cysts of Echinococcus multilocularis were very susceptible to infection. Aspects of the responses of gerbils to this infection were examined to determine if they could be related to the progress of the infection. Hematologic changes observed during the infection included anemia, reticulocytosis, lymphocytopenia, neutrophilia, monocytosis, and eosinopenia; these changes were related to the size of the infection. Infected gerbils also produced specific protein-A binding antibodies to E. multilocularis. At 14 weeks after inoculation, infected gerbils showed splenomegaly and somewhat elevated serum transaminase levels, although serum 5'-nucleotidase levels were normal.