摘要:

AbstractHistology, histochemistry, and ultrastructure of the Harderian gland and lacrimal gland of the lizardPodarcis s. siculawere investigated. The Harderian gland, located at the medial corner of the orbit, can be divided into three zones showing different tinctorial features either with Mallory or hematoxylineosin stains. The glandular cells of the acinar medial zone secrete predominantly acidic sulphated mucosubstances. The acinar cells of the intermediate zone contain secretory granules that show a weak reaction to the histochemical tests for mucosubstances. The lateral zone has a tubulo‐acinar type of structure and tests strongly for proteins, whereas Alcian‐PAS staining is very weak. The lacrimal gland is smaller than the Harderian gland and lies in the region of the posterior commissure of the eyelids. It shows the same histological and histochemical characteristics of the medial zone of the Harderian gland, i.e., it is mucous secreting. At the ultrastructural level the zonation is well defined, especially when the secretory granules are examined. Granules of the mucoid type are found in the lacrimal gland and the medial zone of the Harderian gland. The secretory granules of the lateral part of the Harderian gland show a composite structure never described before. Therefore, they have been called “special secretory granules”. Each of these granules is composed of three sharply separated components. It is not known whether the three components correspond to different secretions. Histochemical tests suggest that they are of the serous type. Both mucous and serous granules are secreted by the same glandular cells of the intermediate zone of the Harderian gland. The two types of granules usually occupy different cell compartments. The mechanism of secretion appears either merocrine or apocrine in both the Harderian gland and the lacrima

ISSN:0003-276X    

DOI:10.1002/ar.1092260302

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe capacity of the dental pulp to form calcified tissue was examined in papilla cells dissociated from first molar tooth germs of the neonatal mouse and isografted in the spleen for up to 7 days. To obtain papilla cell populations without odontoblasts, pulpal mesenchyme was isolated mechanically from the enamel organ after 0.1% trypsin treatment and rolled on a membrane filter. On day 3 after transplantation, the grafted papilla cells had changed into large, spindle‐shaped cells, and initial calcification with needle‐like crystals began in association with the collageneous matrix surrounding those cells. On day 7 after transplantation, the spindle cells transformed into odontoblast‐like cells containing well‐developed secretory organelles, and irregular, but nontubular, calcified tissues were commonly observed surrounding the extracellular collagenous matrix. The calcified tissue matrix with cellular inclusions displayed a structure similar to that of osteodentin. During this period, an intense positive reaction for alkaline phosphatase (ALPase) activity was demonstrated along the cell membranes of the odontoblast‐like cells aligned at the periphery of forming calcified tissue. Enzymatic activity could not be detected on the cells incorporated completely into osteodentin‐like matrix. The present results show that the papilla cell population transplanted into the spleen formed osteodentin‐like material, thus demonstrating the capacity of papilla cells to produce cal

ISSN:0003-276X    

DOI:10.1002/ar.1092260303

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

年代:1990

数据来源: WILEY

摘要:

AbstractThis study investigated the relationship between the fine structure of the main excretory duct (MED) epithelia and the subepithelial capillaries of the major salivary glands (parotid, submandibular, and sublingual) in the rat. The MED subepithelial capillaries vary in type (fenestrated and continuous), number of fenestrae present in the available fenestrated endothelium (the attenuated area of endothelium), and number of capillaries per unit length of epithelium.In the parotid gland, continuous capillaries predominate, and the capillary density per 200 μm of epithelium (1.73 in region I and 1.03 in region II) is lower than in the other two glands, as is the number of fenestrae per 10 μm of available endothelium (1.97 in region I and 1.25 in region II). The submandibular gland has mainly fenestrated capillaries. The capillary density per 200 μm of epithelium (4.46 in region I and 5.51 in region II) is higher than in the other two glands, as is the number of fenestrae per 10 μm of available endothelium (4.82 in region I and 7.90 in region II). Similarly, in the sublingual gland, fenestrated capillaries are dominant. The density of capillaries per 200 μm of epithelium (4.15 in region I and 4.31 in region II) is intermediate between the parotid and submandibular glands, as is the number of fenestrae per 10 μm of available endothelium (2.98 in region I and 3.83 in regio

ISSN:0003-276X    

DOI:10.1002/ar.1092260304

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

年代:1990

数据来源: WILEY

摘要:

AbstractHuman retinas from persons with diabetic retinopathy and agematched controls were rendered acellular by sequential detergent treatment. The resulting network of microvascular extracellular matrix (ECM) materials, including basement membranes (BMs), was compared by TEM and, following cryofracture, by SEM. Our study demonstrates that in diabetics, retinal capillary BM complexes are generally thickened and that their ECM subcomponents, including BM leaflets and BM‐like pericytic matrix (PCM), are differentially altered. Two diabetic microvessel types were identified. In type A vessels, ECM expansion is manifested by loosely arranged combinations of concentric PCM layers and collagen fibrils with thickened subendothelial (EBM) and pericyte (PBM) BM leaflets. Type B vessels show densely compact central PCM masses and poorly recognizable EBMs and PBMs. In both types, Müller cell BMs (MBMs) are relatively unaffected. High‐resolution SEM shows tissue‐specific features in normal EBM and MBM surfaces, but disease‐related topographic changes are not evident. It is possible that the ECM arrangements identified in our study relate to different microvessel domains and that their specific morphological features may play important roles in the pathogenesis of diabetic retinopathy including capillary closure and neovascula

ISSN:0003-276X    

DOI:10.1002/ar.1092260305

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

年代:1990

数据来源: WILEY

摘要:

AbstractThis paper compares patterns of histologic change in an archaic Native American population with those in modern white populations. Histologic sections were removed from core biopsies taken from the anterior femoral cortex of an archeologic sample of Pecos Indians. The data demonstrate many microstructural similarities between the Pecos and modern populations, even though they were genetically and culturally distinct. Pecos women had small Haversian canals and large osteon mean wall thickness, with no clear evidence of an intracortical bone volume deficit even in the older age groups, although significant marrow cavity expansion occurred in both males and females with age. No striking relationships were found between bone tissue changes and gross geometric changes with age. The data suggest that a more active life‐style is associated with greater osteon mean wall thickness or osteon population density, but that it alone does not protect against significant bone loss on the cortical‐endosteal surf

ISSN:0003-276X    

DOI:10.1002/ar.1092260306

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe increase in both glucose 6‐phosphatase and hexokinase activities in brown adipose tissues of cold‐exposed mice probably relates to thermogenesis by the substrate cycle between glucose 6‐phosphate and glucose (Watanabe et al.:Anatomical Record219:39—44, 1987). To clarify the factors causing the simultaneous increase, we examined biochemically the effects of uni‐ or bilateral surgical denervation of brown adipose tissues, of adrenalectomy, or of streptozotocin injection on the increase in the two activities in the tissues of cold‐exposed mice. Further, the effects of denervation on the increase were also examined histochemically. The simultaneous increase in the two activities was inhibited in the denervated tissues of cold‐exposed animals in biochemical and histochemical experiments. However, the increase in the activities was not inhibited in the tissues of animals exposed to cold after adrenalectomy or streptozotocin injection. The results suggest strongly that the activation of the substrate cycle in brown adipose tissues of cold‐exposed mice is caused by a transmitter released from sympathetic nerve endings, probably

ISSN:0003-276X    

DOI:10.1002/ar.1092260307

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

年代:1990

数据来源: WILEY

摘要:

AbstractDuring perinatal development, when the size of the Sertoli cell population is determined, Leydig cells produce β‐endorphin, a peptide which may interact with Sertoli cells to modify their FSH‐responsiveness, as suggested by our previous work. The goal of the present study was first, to test directly the possibility that β‐endorphin modifies the proliferative response of neonatal Sertoli cells to FSH, and second, to gain information on a mechanism(s) involved in any observed effect. We treated isolated 6‐day‐old Sertoli cells with FSH or vehicle in vitro and measured their incorporation of exogenous, radiolabeled thymidine with quantitative autoradiography. After 2 days in culture with FSH, we detected a 10‐fold increase in the rate of Sertoli cell proliferation. The level of cell division in these FSH‐treated cultures was identical to that in other cultures exposed to cAMP under similar conditions. In addition, inclusion of β‐endorphin 3 hr prior to FSH or cAMP decreased the effect of the hormone by 50% but left the cAMP response unchanged. Thus, β‐endorphin acts on isolated, neonatal Sertoli cells at a point prior to intracellular production of cAMP to suppress their response to FSH. When other cultures were treated with pertussis toxin, a blocker of intracellular GTP‐binding proteins such as Gi, before sequential addition of endorphin and FSH, the effect of β‐endorphin on FSH‐responsiveness was abolished. Moreover, when other cultures were exposed to pertussis toxin in the absence of endorphin, followed by FSH, their response to the hormone was unchanged. Thus, β‐endorphin apparently modifies the proliferative response of neonatal Sertoli cells to FSH via a mechanism involving one or more G proteins. These observations, along with our previous data showing enhanced Sertoli cell division in vivo in the presence of an opiate blocker, point to the existence of endorphin‐mediated communication between Leydig and Sertoli cells during perinatal development and provide new evidence suggesting that paracrine mechanisms modify Sertoli cell function during perinatal development, when the size

ISSN:0003-276X    

DOI:10.1002/ar.1092260308

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe estradiol valerate‐induced polycystic ovarian condition in the rat represents a normal ovarian response to aberrant endocrine stimuli. Although we have shown that removal of one polycystic ovary (hemiovariectomy) results in restoration of cyclicity and normal morphology in the remaining ovary by 1 week, nothing is known about the process of recovery or about the role of the hypothalamopituitary unit in initiating recovery. We have therefore examined ovaries at 3, 12, 24, 48, and 120 hours following removal of the contralateral polycystic ovaries. The ovarian content and size distribution of healthy and atretic follicles was determined, as well as the occurrence of follicular cysts, type III large follicular structures, and corpora lutea. The plasma LH pattern was also examined at a short postoperative interval. At 3 hours, there was a significant increase in mean ovarian weight that coincided with the emergence of healthy large secondary follicles. By 12 hours, there was a significant sustained diminution in the number of atretic follicles of all sizes, but the total number of healthy follicles did not increase significantly until 120 hours. The cystic follicles had all but disappeared by 120 hours because of mechanical compression by newly developing ovarian tissue. Ovarian recovery is, therefore, biphasic, consisting of a very early diminution in atresia coincident with, and perhaps caused by, a major alteration in the plasma LH pattern. The second phase is characterized by a wave of follicular recruitment and developmen

ISSN:0003-276X    

DOI:10.1002/ar.1092260309

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe postnatal development of gap junction formation and cell‐to‐cell communication were investigated in male rats from 10 through 40 days of age. These junctions initially appeared between adjacent folliculo‐stellate cells on day 20. Their numbers increased until the animals reached the age of 40 days, when their frequency reached a level that resembled that found in adults. The ontogeny of these junctions was examined in rats treated with luteinizing hormone releasing hormone (LH‐RH) or testosterone. The two hormones were injected for 1 week into rats aged 3, 13, 23, or 33 days. The appearance of gap junctions was accelerated in a similar fashion by LH‐RH and testosterone, with their formation and numbers being advanced by 10 days over that observed in the untreated controls. The results suggest a role for the gonadal steroid hormones in the formation of gap junctions in the rat h

ISSN:0003-276X    

DOI:10.1002/ar.1092260310

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

年代:1990

数据来源: WILEY

摘要:

AbstractThis study investigated the relationship between gap junction formation and sex steroids in the male rat anterior pituitary gland. Animals were castrated at 5 days of age and separated into the following three groups: (1) oiltreated controls, (2) those injected with LH‐RH, and (3) those given testosterone. On days 10, 20, 30, and 40, five rats in each group were sacrificed and their hypophyses removed for ultrastructural examination. When compared with age‐matched, intact animals, there was a marked suppression in follicular development and in the number of gap junctions present in the pituitary glands of both the castrated controls as well as the castrates given luteinizing hormone releasing hormone (LH‐RH). In contrast, the morphology of these structures in the animals given testosterone was indistinguishable from that observed in the intact controls. These observations provide more definitive evidence that in the male rat pituitary gland maturation of the structural organization of the follicles, including gap junction formation, requires an intact hypophyseal‐gonadal axis and is highly dependent on the hormone testo

ISSN:0003-276X    

DOI:10.1002/ar.1092260311

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

年代:1990

数据来源: WILEY