摘要:

AbstractThe cytochemical localization of alkaline phophatase (ALPase) activity and the autoradiographic distribution of glucagon receptors were examined in the plasma membrane of cultured mouse hepatocytes. After 24 hours of culture, ALPase activity was exclusively localized on the plasma membrane in areas of cell‐cell contact, and glucagon receptors were more numerous in the plasma membrane at the periphery of re‐formed cell trabeculae. These results indicate that plasma membrane regionalization of hepatocytes, lost by cell isolation, reappeared during culture. The cells maintained this plasma membrane regionalization until 48 hours of culture. By 72 hours of culture, however, ALPase activity was seen on the external surface of all regions of plasma membrane, and the glucagon receptors decreased markedly in number and became scattered in all regions of plasma membrane. Thus, the re‐formed plasma membrane regionalization disappeared in the cells by 72 hours of cu

ISSN:0003-276X    

DOI:10.1002/ar.1092140102

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

年代:1986

数据来源: WILEY

摘要:

AbstractThree fiber types—coarse, granular, and fine—were readily identified in histochemical cryostat sections of human extraocular muscle (EOM). The cryostat retrieval method was utilized to identify these three fiber types in serial electron microscopic thin sections. Using morphometric techniques, five mitochondrial variables (mitochondrial volume fraction, mitochondrial profile size, mitochondrial profile density, and clusters of two or of three or more mitochondrial profiles) were determined for a total of 162 histochemically identified fibers from two regions (orbital and global zones) from six EOMs. Coarse fibers had numerous large‐sized mitochondrial profiles, often occurring in clusters. Granular fibers had fewer and smaller‐sized profiles scattered across the fiber. Fine fibers had the most numerous, but smallest‐sized mitochondrial profiles. Despite significant differences in group (fiber types) means for the mitochondrial variables, no single variable was sufficient for separating fiber types into distinct populations. Although a scattergram plot of two variables was sufficient to separate orbital zone fibers, a computer‐generated, multivariate discriminant analysis was needed to separate the global zone fibers into distinct populations. These results will aid future studies on normal and pathological human EOM by providing a morphometric basis for identifying fiber types in the orbital and g

ISSN:0003-276X    

DOI:10.1002/ar.1092140103

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe extensor digitorum longus muscles of 4–6‐week‐old normal mice (129 ReJ) and dystrophic mice (129 ReJ dy/dy) were orthotopically transplanted. Grafted muscles were examined 1, 3, 7, 14, 20, 50, and 100 days post‐transplantation. The myofibers of both types of grafts underwent a similar time course of necrosis and regeneration. Other than during the initial necrotic response, no evidence of necrotic myofibers was found in either type of grafted muscle. At 100 days post‐transplantation, the grafted normal and dystrophic muscles were essentially similar, except that the dystrophic graft was of smaller size. Based on a comparison of the number of myofibers found at the 100‐day grafts' widest girths [631 ± 59 SEM, for normal grafts (Bourke and Ontell, 1984); 631 ± 74 SEM, for dystrophic grafts], it is suggested that the regenerative capability of traumatized 4–6‐week‐old dystrophic muscle is similar to that of traumatized normal muscle. At 100 days post‐transplantation, the grafted dystrophic muscle appeared “healthier” than untraumatized muscle from age‐matched dystrophic mice, having less variation in myofiber diameter, better fascicular organization, and less connective tissue. The transplantation system demonstrates the possibility of modifying the expression of genetic programming of myopathic disorders using

ISSN:0003-276X    

DOI:10.1002/ar.1092140104

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

年代:1986

数据来源: WILEY

摘要:

AbstractCytochemical and biochemical glucose 6‐phosphatase (G6Pase) activity and fiber type composition were studied in soleus (SOL) and gastrocnemius (GC) muscles of mice. The SOL is a red muscle which contains numerous type I fibers (60%) and relatively few type II fibers (40%). The GC is a white muscle which contains numerous type II fibers (90–100%) and very few type I fibers (0–10%). In the SOL and GC, cytochemical G6Pase activity was localized in the sarcoplasmic reticulum, lateral elements of triads, myonuclear envelope, and in the endoplasmic reticulum and nuclear envelope of endothelial cells. Differential centrifugation showed that G6Pase activity was recovered in the 105,000g pellet (microsomal fraction). Histochemical enzyme activity in type II fibers was slightly higher than that in type I fibers. Biochemical G6Pase activity in the GC was significantly higher than that in the SOL. The possible functional significance of G6Pase in skeletal muscles was disc

ISSN:0003-276X    

DOI:10.1002/ar.1092140105

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

年代:1986

数据来源: WILEY

摘要:

AbstractBone cells obtained by digestion of fetal mouse or chicken calvaria were tested for their ability to form or resorb bone in vitro. The isolated cells were precultured for 6 days and subsequently cocultured for 11 days with periosteum‐free noninvaded fetal mouse long bone rudiments. Bone formation and resorption during coculture were evaluated by histology and45Ca release from prelabeled bones. The calvarial origin of cells in cocultures was traced by labeling the cells with3H‐thymidine before coculture, followed by autoradiography.Many osteoblasts and osteoclasts as well as fibroblasts developed frommouseperiosteal cells released late in the sequential digestion procedure and previously denoted as “osteoblastlike” (BL). No or few osteoblasts and osteoclasts but many fibroblasts developed from early released cell fractions that have previously been denoted as “osteoclastlike” (CL).Only osteoblasts and fibroblasts but not osteoclasts developed fromchickencalvarial cell fractions. The osteoblasts developed primarily from cell fractions from the inner layer of the periosteum, previously denoted as “osteoblastlike” (OB). Cells obtained from the outer layer of the periosteum (PF) gave rise mainly to fibroblasts.These studies show that osteoblast and osteoclast precursor cells are maintained in monolayer cultures of periosteal cell fractions. However, sequential digestion ofmousecalvaria does not lead to separation of the two types of bone cells. Rather, osteoclast and osteoblast precursors are released jointly, from the periosteal cell layers closest to the bone surface. In thechickencell fractions osteoclast precursors are absent after preculture, resulting in a more homogeneous population of osteoblast and fibroblast but not osteoc

ISSN:0003-276X    

DOI:10.1002/ar.1092140106

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe effect of a diabetogenic dose of streptozotocin on the secretory activity of ameloblasts was investigated in the rat incisor by radioautography. One group of male Sprague‐Dawley rats was injected intravenously with streptozotocin in citrate buffer (pH 4.5). One hour later, this group was again injected intravenously with3H‐proline (2 mCi/kg). A control group of animals was injected with3H‐proline only. All the animals were sacrificed in groups of three at 5 min, 1 h, 2 h, 4 h and 8 h after3H‐proline injection by perfusion with 3% phosphate‐buffered formaldehyde followed by an additional perfusion with 2.5% phosphate‐buffered glutaraldehyde. The incisors were extracted with the jaws, demineralized, and prepared for radioautographic observations and analysis. The principal effects of streptozotocin were as follows: There was an inhibition of3H‐proline incorporation into the secretory ameloblasts at 5 min after injection. This was followed by a larger uptake and a slower passage of the label out of the cells into the enamel matrix than that seen in the control sample. Finally, there was a slower secretion of labeled proteins out of Tomes' processes between 1 and 4 h after injection.Therefore, streptozotocin had a temporary inhibitory effect on the incorporation and secretion of3H‐proline by the secretory ameloblasts of the rat incisor. This effect was present for about 4 h and was completely reversed 9 h after streptozo

ISSN:0003-276X    

DOI:10.1002/ar.1092140107

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe possibility of turnover of the epithelial duct cells was examined in the adult mouse pancreas by radioautography following continuous administration of3H‐thymidine for periods varying from 1 h to 60 days. One hour after an injection of3H‐thymidine, the label observed in small and large ducts was low but increased with the duration of the continuous infusion of3H‐thymidine and reached a level of about 67% cells labeled after 60 days. The rate of duct cell labeling was estimated from the regression line of the labeling index vs. time in four types of ducts classified according to their inner diameter and the presence of the adventitia and was given as 0.60% cells per day in small (adventitia‐free) ducts (π 4–12 μm), 0.89%, 1.02%, and 1.23% cells per day in large (adventitia‐including) ducts (π 15–29, 30–49, and 50–160 μm respectively). In contrast, the labeling index of aciner cells after a 60‐day infusion indicated an addition of only 0.02–0.07% per day, and that of islet cells 0.14–0.22% per day.It is known that most parenchymal cells belong to either expanding or renewing cell populations. The acinar cells of the pancreas have been shown to constitute an expanding population, a conclusion confirmed by the low addition of cells observed in the present work. However, the relatively high rate of cell addition in the duct epithelia indicates that they may turn over in a period of 2.7 months in the case of large ducts and 5.6 months in the case of small ducts. It is proposed that the added cells replace cells carried away by t

ISSN:0003-276X    

DOI:10.1002/ar.1092140108

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe coagulating gland of rodents, which is part of the prostatic complex, secretes components of semen. Although possessing some ultrastructural features of other exocrine glands, the mechanism of secretion by these cells has been problematic. In the present study the pathway, kinetics, and mode of secretion in the coagulating gland of the mouse were studied by light and electron microscope autoradiography at intervals between 10 minutes and 3 hours after injection of3H‐fucose. The majority of silver grains overlay the Golgi apparatus at the initial interval, but in addition, more than a third of the grains were associated with extremely distended cisternae of the rough endoplasmic reticulum. At later intervals, radioactivity of the Golgi apparatus and the endoplasmic reticulum declined, while labeling of secretory granules increased greatly. Luminal contents became labeled 1 hour after administration of precursor. The results indicate that the pathway for secretion of glycoproteins proceeds through the Golgi apparatus to secretory granules and the glandular lumen, as in many other cells. In particular, heavy labeling of secretory granules at later intervals indicates that merocrine secretion is the most likely mechanism in the coagulating gland. However, the unusual observation that a significant proportion of grains overlay the rough endoplasmic reticulum at the initial interval raises the possibility that some fucose is incorporated into glycoproteins in the endoplasmic reticulum, as has been reported for other cell types with similarly configured endoplasmic reticulu

ISSN:0003-276X    

DOI:10.1002/ar.1092140109

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

年代:1986

数据来源: WILEY

摘要:

AbstractFollowing unilateral ovariectomy in the rat, the remaining ovary undergoes rapid compensatory changes including an increase in the number of antral follicles (follicular activation) and an increase in ovarian weight (compensatory ovarian hypertrophy). The ovary is innervated by the vagus nerve (Burden et al., 1983). In the present study, the effects of right and left cervical vagotomy and abdominal vagotomy on follicular activation and compensatory ovarian hypertrophy in the remaining right or left ovary were compared 15 days after unilateral ovariectomy. Neither right nor left cervical vagotomy affected compensatory ovarian hypertrophy of the right or left ovaries but abdominal vagotomy depressed compensatory ovarian hypertrophy in both the right and left ovaries. Left cervical vagotomy did not inhibit follicular activation, but right cervical vagotomy prevented follicular activation in the right but not left ovary. Also, abdominal vagotomy inhibited follicular activation in the right but not the left ovary. In animals with both ovaries which were subjected to the left or right cervical vagotomy or abdominal vagotomy follicular counts in both right and left ovaries were similar. Collectively, these data indicate that the vagus nerve participates in follicular activation after unilateral ovariectomy. The data also indicate that the right ovary is more dependent on vagal influences for follicular activation than the left ovary.

ISSN:0003-276X    

DOI:10.1002/ar.1092140110

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe three‐dimensional arrangement of intrahepatic lymphatics was demonstrated in the rabbit liver by scanning electron microscopy of corrosion casts. These casts were prepared by injecting resin into the common bile duct at a pressure that caused resin to leak from the bile ducts in the small portal tracts and drain into the lymphatics. The lymphatic channels were composed of straight vessels and anastomosing short side branches. The anastomoses were especially rich at the bifurcation of the portal tracts and formed a network. The terminal branches were blind‐ended. Constrictions suggesting valves were occasionally obser

ISSN:0003-276X    

DOI:10.1002/ar.1092140111

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

年代:1986

数据来源: WILEY