摘要:

AbstractThe mammalian intermediate fetal kidney, the mesonephros, is known in different species to excrete body waste products during a limited period of fetal life. Recently, the mesonephros and its derivatives have been shown to influence gonadal functions in several ways. Thus, the mesonephric cells are responsible for regulating the onset of meiosis in different mammals by the secretion of two substances, a meiosis‐inducing substance (MIS) and a meiosis‐preventing substance (MPS).In this paper, the relation between mesonephric kidney function and its influence on the gonads is reviewed through literature studies. It seems that cessation of mesonephric excretion precedes onset of meiosis in the ovary in different species.It is suggested that the mesonephric renal function interferes with synthesis and/or secretion of MIS or that the excreted products may interfere with the responsiveness to MIS of the germ ce

ISSN:0003-276X    

DOI:10.1002/ar.1092100402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe binding of glucagon to the cell surface and the pathway of intracellular transport of the hormone in isolated mouse hepatocytes were studied by autoradiography, colloidal gold‐labeled glucagon (Au‐glucagon), and biochemical methods. In cells incubated with1251‐glucagon at 4°C, the label was mainly localized to the plasma membrane even after 60 min of incubation. At 20°C, the labeled ligand was internalized by the cells and the amount of internalized ligand increased with time of incubation. At 37°C, the ligand was rapidly internalized and found to be associated with coated or uncoated vesicles. Au‐glucagon experiments revealed clearly the process of internalization of glucagon. Au‐glucagon bound to the plasma membrane was transported to coated regions and then internalized into vesicles via coated pits. Biochemical results supported these findings from autoradiography and Au‐glucagon experiments. Thus, glucagon is internalized by hepatocytes via receptor‐medi

ISSN:0003-276X    

DOI:10.1002/ar.1092100403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe data on mouse skin thickness reported here was prompted by the need to know the true postion of basal cells of the epidermis and hair follicles as these are important “cells at risk” for a variety of skin reactions including carcinogenesis following exposure to radiation. There is little reliable data in the literature and most previous reports have ignored the shrinkage of skin that occurs because of its natural elasticity.The values determined for mouse flank skin in telogen‐the resting phase of the hair cycle for the different skin layers‐are epidermis 10 μm, corium 250 μm, adipose layer 150 μm, and hair follicle depth 150 μm. Three days after chemical depilation which triggers the hair follicles into active cycle (anagen) the epidermis doubles in thickness, remains at this value for 7 days, and then gradually returns to telogen values by day 18. The corium and adipose layers also increase significantly to reach approximately 390 μm and approximately 260 μm, respectively, by day 10 and then return to control values from day 15 onward. The change in hair follicles depths are more dramatic with active follicle basal cells reaching approximately 450–550 μm into the adipose layer between days 7 and 15.One important finding is that chemical depilation does not affect the telogen thickness of skin‐the teleogen values for the epidermis and dermis immediately prior to and immediately after depilation were similar to those 23 days later at the beginning of the

ISSN:0003-276X    

DOI:10.1002/ar.1092100404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractBilateral section of the pelvic parasympathetic nerves (pelvicneurectomy) on day 5 of pseudopregnancy had no effect on the wet weight of ovaries, uteri, and/or cervices, but at day 9 serum progesterone was reduced to approximately half that of sham‐operated animals. Collagen in the cervix was visualized with picrosirius red staining under polarization microscopy. Pelvic neurectomy decreased the birefringence of Type 1 collagen in the cervix to less than half that of sham operated animals. The decreased birefringence, an index of the organization of collagen fibers, is believed to be attributable to reduced progesterone levels. Alternatively, the pelvic nerve may directly influence mucopolysaccharides or collagenolytic enzymes in the cervi

ISSN:0003-276X    

DOI:10.1002/ar.1092100405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractGastric K+‐NPPase represents a partial reaction of the (K+‐H+)ATPase system, which is considered to be the proton pump in mammalian parietal cells. In the present paper, K+‐NPPase activity was cytochemically studied by the method of Mayahara et al. (1980) in gastric glands of birds, amphibia, and mammals, either in the resting state induced by cimetidine or after stimulation of HC1 secretion by histamine.The gastric K+‐NPPase cytochemical reaction was localized only in oxyntic cells of the gastric mucosa in the three species tested.The subcellular distribution of the K+‐NPPase reaction product drastically changes with the secretory state of HC1. In resting cells, the K+‐NPPase staining is associated with the membranes of the endocellular tubular system while in HC1‐secreting cells, it is associated with the plasma membrane of the elaborate secretory surface characteristic of this functional state. The above results demonstrate that the same enzymatic activity, which is associated with the gastric proton pump, is present in both membranous systems of the oxyntic cell secretory pole. This fact supports the proposal that the tubular system represents a membrane reserve that inserts the proton pump into the luminal plasma membrane in vertebrate oxyntic cells under the action of HC1

ISSN:0003-276X    

DOI:10.1002/ar.1092100406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe origin and development of osmiophilic inclusion bodies (OIB) type A of granular pneumocytes were morphologically studied in chicken lungs. The OIB type A were formed by a process of twisting and progressive spiralling of profiles of the rough endoplasmic reticulum (RER). No evidence has been found in favor of a mitochondrial or Golgi‐related origin of OI

ISSN:0003-276X    

DOI:10.1002/ar.1092100407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe effects of chronic ACTH treatment (Depot Synacthen, 100 μg/day) on the morphology of the rat adrenal were studied in animals treated for 1 to 18 days. The gross weight of the adrenal increased up to tenfold, but although mitotic figures were seen after 3 days in the glomerulosa region, most of this is attributable to a vast increase in blood content. After 3 days of treatment the sinusoids in the reticularis became extremely dilated, and red blood cells penetrated the endothelial wall to become tightly packed around the cortical cells. This led to the gross distortion of the organization of the cortical tissue and after 7 days the cells in the reticularis region were isolated from each other by the continual infiltration of red blood cells. These changes gradually progressed outward so that other regions of the cortex became similarly affected. Eventually the cord‐like arrangement of the fasciculata was disrupted. After 18 days of treatment, most of the cortex was involved and only a very thin layer of cells lying beneath the adrenal capsule was seemingly unaffected. Another major effect of corticotrophin treatment was the gradual loss of cellular differentiation, particularly of glomerulosa cells. Although the glomerulosa appeared normal after 1 day of treatment, cells of the fasciculata abut directly on the connective tissue capsule following 3 days of ACTH administration. Eventually glomerulosa cells disappeared almost completely, although there was no sign of cellular necrosis. It is likely that glomerulosa cells are transformed into fasciculata‐type cells under ACTH treatment. This interpretation is consistent with functional changes that occur at the same time, including the loss of aldosterone synthetic capa

ISSN:0003-276X    

DOI:10.1002/ar.1092100408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe effects of hemithyroidectomy (hemiTX) and complete thyroidectomy (TX) on the cellular composition and the mitotic activity of the anterior pituitary gland were examined in genetically thyrotropin (TSH)‐deficient female Snell dwarf mice (dw/dw) and in phenotypically normal female mice (?/+) from the same strain. In normal (nondwarf) mice, both hemiTX and TX reduced the percentage of acidophilic (orange G‐positive) cells and increased the percentage of thyrotropic (aldehyde fuchsin [AF]‐positive) cells, whereas the percentage of gonadotrophs (PAS‐positive cells) and chromophobes (unstained cells) was not affected. Both interventions increased the mean mitotic activity rate (MMAR) of the anterior pituitary lobe. This effect was related to the enhancement of the MMAR of acidophilic cells and, particularly, thyrotropic cells. The MMAR of thyrotrophs in thyroidectomized normal mice was significantly higher than that in sham‐TX controls or in hemithyroidectomized animals.In Snell dwarf mice, neither hemiTX nor TX affected the percentage of the various cell categories (PAS‐positive, unstained, and extremely rare AF‐positive cells) in the anterior pituitary lobe. Furthermore, neither hemiTX nor TX substantially influenced the MMAR of the gland. No mitotic figures were found in the AF‐positive cells. Since the AF‐positive cells in the anterior pituitary of dwarf mice completely failed to respond to hemiTX or TX, we believe they are not true thyrotropic cells.Using electron microscopy, we confirmed a lack of somatotrophs, mammotrophs, and normal thyrotrophs in the anterior pituitary of Snell dwarf mice. The results provide morphological evidence of inactivity of the hypothalamo‐pituitary‐thyroid axi

ISSN:0003-276X    

DOI:10.1002/ar.1092100409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe formation of the chordae tendineae of the left atrioventricular valve in the chick embryo is described using scanning electron microscopy. These supportive structures for the valve cusps develop between days 6 and 13 of incubation. Elevations which represent the primitive papillary muscles form on the ventricular wall. These elevations bifurcate into thin, weblike folds which are attached to the primitive valve cusps. The folds are the primordia of the chordae tendineae. Linear ridges develop on the web between the cusp and papillary muscle. These ridges alternate with depressions. The depressions become perforate to create the individual chorda from the linear ridges. Multiple perforations form initially but they typically consolidate to create one large aperture between two chordae. Some interchordal connections of tissue do persist throughout the period studied. During the period of perforation, prominent rounded cells are typical of the endocardium between the chordae. These cells are similar at the scanning electron microscope level to those present in the formation of the foramina secunda of the atrial septum. Primary, secondary, and tertiary chordae tendineae appear to develop in the same manner. First order chordae (those attached at the free margin of a cusp) are not found in the chick embryo. The majority of the chordae are second order, which insert into the ventricular surface of the cusp a short distance from the free edge. These chordae typically have a horizontal banding or grooving along their length. Third order chordae which extend from the papillary muscle to the ventricular wall are also present. It is suggested that chordal development is a programmed cellular and hemodynamic event.

ISSN:0003-276X    

DOI:10.1002/ar.1092100410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractS‐100 protein, isolated from mammalian brain, has widely been used for immunohistochemical marker of the glia cells and the cells derived from the neural crest. In the present study, we made anti S‐100 protein antibody and studied the immunoreactive distribution of S‐100 protein in the cutaneous nervous system. Albino rabbits were immunized with S‐100 protein and complete Freund adjuvant, and antiserum was purified by ion‐exchange chromatography. Formalin‐fixed normal human skin and sciatic nerve of rat were examined by the PAP method. S‐100 protein was detected in Schwann cells of sciatic nerve of rat and cutaneous nerve bundles of human skin specimens. Meissner corpuscles and inner core cells of Pacinian corpuscles of human skin were S‐100 protein positive. These findings suggest that the staining of S‐100 protein with PAP method is a simple and reliable method to demonstrate the cutaneous nervous system. Also, lamellar cells of Meissner corpuscles and inner core cells of Pacinian corpuscles are indicated to be Sc

ISSN:0003-276X    

DOI:10.1002/ar.1092100411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY