The occurrence and distribution of certain polypeptides within the human carotid body

Summary Both carotid bodies from 26 patients coming to necropsy were fixed in 10% neutral buffered formalin and sections 4 m thick were stained for various peptides by use of the immunogold technique. The results show that the human carotid body contains met- and leu-enkephalin, substance P, vasoactive intestinal peptide (VIP), neurotensin and bombesin. The distribution of these six peptides within the carotid body differs. Thus met- and leu-enkephalin are both present predominantly within glomic chief cells but with a marked tendency to favour the dark variant of these cells. Substance P and VIP both show a weak immunoreactivity in comparison to the enkephalins and are present in all three variants of chief cell. Neurotensin shows the weakest immunoreactivity of all and is restricted to a few glomic chief cells in a minority of cases. Bombesin also shows a weak immunoreactivity in glomic chief cells but a strong reaction in glomic arteries and arterioles. In these vessels bombesin appears to be confined to smooth muscle cells in the media but we cannot say whether it is secreted by them or merely bound to receptor sites on their membranes. These findings are related to quantitative data on the concentration of peptides in the human carotid body from a previous paper with which we were associated.     

Extracellular matrix influences hormone and protein production by human chorionic villi

Summary Increasing evidence confirms that the extracellular matrix greatly influences cell behaviour and function. Collagen and fibrin are in contact with trophoblast throughout pregnancy. To investigate whether these two matrices influence hormon production by the trophoblast, explants from first-trimester chorionic villi were cultured for up to 30 days either a) in medium with agitation, b) embedded in type-I collagen (three-dimensional gels), or c) embedded in fibrin (three-dimensional gels). The supernatant culture medium was changed every 48 h and tested by radioimmunoassay for hCG, progesterone and pregnancy-associated plasma protein A. In addition, after 3, 7, 15, and 30 days of culture villi were fixed and studied by light and electron microscopy. Embedding in the extracellular matrix showed higher and longer-lasting production rates of all measured products and superior structural preservation as compared to cultures with agitation. Collagen matrix proved to be superior to fibrin. As established by several tests, this difference was neither due to thrombin used to polymerize fibrinogen, nor to differences in the diffusion rates through the two different matrices used. We conclude that extracellular matrix, particularly collagen, influences the synthesis of trophoblastic products. Embedding of the villous explants in three-dimensional gels constitutes a new method for long-term cultures of chorionic villi.This study was presented at the workshop Placental-and decidual-specific protein synthesis and secretion: regulation, role and interaction, Zemun, Belgrade, Yugoslavia, 19–20 May, 1988 (Bischof and Castellucci 1988; see also J. Aplin 1989), and at the 11th Rochester Trophoblast Conference, Rochester, N.Y. USA, 9–12 October 1988 (Castellucci et al. 1988)     

促胰液素对血管灌流大鼠离体胃运动的抑制作用

本工作采用血管灌流大鼠离体胃制备,探讨促胰液素对胃运动的影响。结果表明:(1)促胰液素能明显抑制胃窦自发和五肽胃泌素兴奋的胃运动;(2)抗促胰液素血清可完全取消促胰液素的抑制胃窦运动作用;(3)抗生长抑素血清和消炎痛都能阻断促胰液素的抑制胃窦运动作用。上述结果提示,促胰液素的抑制作用除通过直接作用于促胰液素受体外,还可能部分通过胃窦局部生长抑素和前列腺素介导来抑制胃的运动。     

中国九个人群耵聍的遗传多态性

报道了九个人群的耵聍位点基因。计算表明中国各族人群在耵聍位点上的遗传分化程度非常大,固定指数F_(ST)=0.22。本文根据耵聍基因频率在我国和邻近地区的分布趋势,认为亚洲东北地区应是干型基因的起源地,目前世界上耵聍位点基因频率分布格局主要是基因扩散的结果,而非选择作用造成的。     

中国3个地区汉族人群补体C6的遗传多态性研究

运用聚丙烯酰胺凝胶等电聚焦(PAGIF)和免疫吸引技术,研究了3个地区汉族人群的C6多态性。得到的基因频率如下:漳州市——C6*A:0.4634、C6*B:0.5000、C6*R:0.0366(C6*B2:0.0317);成都市——C6*A:0.4975,C6*B:0.4484,C6*R:0.0545(C6*B2:0.0395);哈尔滨市——C6*A:0.4708,C6*B:0.5219,C6*R:0.0073(C6*B2:0.0073)。蒙古人种的C6*A频率一般都低于0.5,高加索人种的C6*A频率一般都高于0.6。黑人则介于两者之间。蒙古人种与高加索人种的另一个区别在于前者的C6*B2频率在0.03到0.07之间,而后者几乎没有C6*B2。     

Coexpression of cytokeratin and vimentin in Rathke's cysts of the human pituitary gland

Summary Immunohistochemistry with monoclonal and polyclonal antibodies revealed the presence of cytokeratins in epithelial cells of Rathke's cysts in the pars intermedia of the human pituitary gland. With monoclonal antibodies specific for individual cytokeratins, the expression of CK 18, CK 8, CK 7, and CK 19 could be shown in these cells. Within the hypophysis, CK 19 and CK 7 were restricted to Rathke's cysts and a few epithelial cell clusters in the pars tuberalis, whereas other cytokeratins were also present in endocrine cells of the pars distalis. Furthermore, vimentin and, focally, glial fibrillary acidic protein (GFAP) were detected in the cystic epithelia. By double labelling, coexpression of cytokeratin and vimentin, GFAP and cytokeratin, and GFAP and vimentin could be demonstrated. Compiled data of all known cases of coexpression of cytokeratin and vimentin in normal cells reveal physiological correlations and suggest a functional significance of this rare type of coexpression of intermediate filament proteins.     

Basement-membrane components associated with the extracellular matrix of the lymph node

Summary Lymph nodes contain an extensive array of extracellular matrix fibers frequently referred to as reticular fibers because of their reticular pattern and positive reaction with silver stains. These fibers are known to contain primarily type-III collagen. In the present study, frozen and plastic-embedded sections of mouse and human lymph nodes were subjected to immunostaining with a panel of monospecific antibodies directed against type-IV collagen, type-III collagen, laminin, entactin, and heparan sulfate proteoglycan. Immunofluorescent staining revealed that, in addition to being uniformly stained with antibodies to type-III collagen, these fibers also stained positively with antibodies to type-IV collagen and to other basement-membrane-specific components. Furthermore, the basement-membrane-specific antibodies stained the outer surface of individual fibers. These same type-III collagen-rich fibers were distinct from blood vascular basement membranes since they did not react with antibodies to factor VIII-related antigen, an endothelial-cell-specific marker. The role of these basement-membrane-specific components associated with the reticular fibers of lymphoid tissue is unknown. However, it is possible that the ligands promote attachment of reticular fibroblasts as well as macrophages and lymphocytes to the extracellular matrix fibers.     

Seasonal changes in circadian rhythms of body temperatures in humans living in a dry tropical climate

Seven volunteers (3 females and 4 males; 3 Caucasians and 4 Africans) participated in two 24 h sessions during the cool dry (CD) and the hot dry (HD) seasons of the sahelian tropical climate. Body temperatures were taken on portable cassette recorders for 24 h. Rectal (Tre) and mean skin (Tsk) temperatures decreased in the HD compared to the CD conditions, meeting one of the criteria for adaptation to heat. No ethnic differences in thermal responses were found. Males and females differed in their body temperature rhythms and in their reactions to heat. Body temperatures were higher in females than in males. Males reacted to heat with a decrease in Tre, without change in the Tre-Tsk gradient. Females showed a decrease in both Tre and Tsk, more marked for Tsk, with an increase in the Tre-Tsk gradient. It was concluded that males showed seasonal acclimatization to heat via a decrease in metabolism confirmed by a decrease in plasma levels of thyroid stimulating hormone (TSH) in the HD condition. Females showed a mixed metabolic and thermolytic type of acclimatization, with an absence of variation in plasma TSH levels. In conclusion, the steady rise in temperature between the CD and HD conditions was sufficient to trigger an acclimatization to heat similar in Caucasian and African subjects, although exposure to the external climate differed widely.     

Serum copper,zinc levels,and copper

Serum copper and zinc levels were determined in 20 healthy women and in 100 women with gynecological tumors. Malignant and benign tumor cases were separated according to their postoperative, histopathological examinations. The stages of malignant and benign tumors were also established histologically. Seventy benign and 30 malignant genital tumors (carcinoma of cervix in situ, cervix, ovary endometrium, and vulva) of the patients were differentiated histopathologically. The serum Cu/Zn ratios of patients were increased significantly from the control group (0.32±0.35) to the benign group (1.22±0.63) and from the benign group to the malignant group (2.24±1.03). Nine of 30 malignant cases were determined as false negative (30%) and 15 of 70 benign cases were determined as false positive (14.2%) according to the serum Cu/Zn ratios of patients. Serum copper levels of 30 malignant and 10 benign tumor cases showed linear correlation with serum ceruloplasmin values.     

Characteristics of human milk glutathione peroxidase

Human milk glutathione peroxidase (GPx) was purified 4500-fold using acetone precipitation and purification by repetitive ion-exchange and gel filtration chromatography with an overall yield of 34%. Homogeneity was established by gel electrophoresis. Using gel filtration, the molecular weight (mol wt) of the enzyme was estimated to be 92 kdalton (kD). The monomeric molecular weight was estimated to b 23 kD from polyacrylamide gel electrophoresis, indicating that the native enzyme consists of four identical subunits. The molecular weight of each subunit was supported by amino acid analysis. Selenium (Se) content of the purified enzyme was 0.31%, in a stoichiometry of 3.7 g-atoms/mol. Data from these studies reveal that GPx provided approximately 22% of total milk Se, but only 0.025% of the total protein.