摘要:

AbstractMorphometric examination using light, scanning electron, and transmission electron microscopy was performed on the lungs from 32 inbred male BALB/cNNia mice between 38 days and 28 months of age.Between 38 days and 9 months of age the changes were primarily those of growth. Alveolar multiplication and total elastic‐fiber length appeared complete by 38 days of age. The major increase in the number of interalveolar pores occurred by 68 days, but there was a significant further increase from 68 days to 9 months of age. At 9 months, approximately 10% of the alveolar wall was formed by pores. Alveolar ducts, the cylindrical core of air central to alveolar mouths, increased more in diameter than length.Between 9 and 28 months the changes were attributed to aging and were different from those reported in humans and other species. Lung volume, alveolar surface area, and total volume of alveolar wall increased with age; there was no change in mean linear intercept and volume proportion of alveolar and alveolar duct air. Total area of pores increased with age, but their number and area fraction of the alveolar wall did not change. No transmission electron microscopic changes were seen in the alveolar walls. We speculate that the morphometric differences between our animals and those studied in other reports may reflect the fact that our animals were specific‐pathogen—free animals and kept under protected circumst

ISSN:0002-9106    

DOI:10.1002/aja.1001700102

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

年代:1984

数据来源: WILEY

摘要:

AbstractVery low hepatic glycogen levels are achieved by overnight fasting of adrenalectomized (ADX) rats. Subsequent injection of dexamethasone (DEX), a synthetic glucocorticoid, stimulates marked increases in glycogen synthesis. Using this system and injecting3H‐galactose as a glycogen precursor 1 hr prior to sacrifice, the intralobular and intracellular patterns of labeled glycogen deposition were studied by light (LM) and electron (EM) microscopic radioautography. LM radioautography revealed that 1 hr after DEX treatment, labeling patterns for both periportal and centrilobular hepatocytes resembled those in rats with no DEX treatment: 18% of the hepatocytes were unlabeled, and 82% showed light labeling. Two hours after treatment with DEX, 14% of the hepatocytes remained unlabeled, and 78% were lightly labeled; however, 8% of the cells, located randomly throughout the lobule, were intensely labeled. An increased number of heavily labeled cells (26%) appeared 3 hr after DEX treatment; and by 5 hr 91% of the hepatocytes were intensely labeled. Label over the periportal cells at this time was aggregated, whereas centrilobular cells displayed dispersed label. EM radioautographs showed that 2 to 3 hr after DEX injection initial labeling of hepatocytes, regardless of their intralobular location, occurred over foci of smooth endoplasmic reticulum (SER) and small electron‐dense particles of presumptive glycogen, and in areas of SER and distinct glycogen particles. After 5 hrs of treatment with DEX, the intracellular distribution of label reflected the glycogen patterns characteristic of periportal or centrilobular regi

ISSN:0002-9106    

DOI:10.1002/aja.1001700103

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

年代:1984

数据来源: WILEY

摘要:

AbstractThis report describes the morphology of the smooth muscle cells, pericytes, and the perivascular autonomic nerve plexus of blood vessels in the rat mammary gland as visualized by scanning electron microscopy after removal of connective‐tissue components. From the differences in cellular morphology, eight vascular segments were identified: (1) terminal arterioles (10–30 μm in outer diameter), with a compact layer of spindle‐shaped and circularly oriented smooth muscle cells; (2) precapillary arterioles (6–12 μm), with a less compact layer of branched smooth muscle cells having circular processes; (3) arterial capillaries (4–7 μm), with “spidery” pericytes having mostly circularly oriented processes; (4) true capillaries (3–5 μm), with widely scattered pericytes having longitudinal and several circular processes; (5) venous capillaries (5–8 μm), with spidery pericytes having ramifying processes; (6) postcapillary venules (10–40 μm), with clustered spidery pericytes; (7) collecting venules (30–60 μm), with a discontinuous layer of circularly oriented and elongated stellate or branched spindle‐shaped cells which may represent primitive smooth muscle cells; and (8) muscular venules (over 60 μm), with a discontinuous layer of ribbon‐like smooth muscle cells having a series of small lateral projections. No focal precapillary sphincters were found.The nerve plexus appears to innervate terminal arterioles densely and precapillary arterioles less densely. Fine nerve fibers are only occasionally associated with arterial capillaries. Venous microvessels in the rat mammary

ISSN:0002-9106    

DOI:10.1002/aja.1001700104

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

年代:1984

数据来源: WILEY

摘要:

AbstractSerial transverse and horizontal sections of the tail of the 26‐day larval lamprey,Lampetra japonica, were observed by light and electron microscopy. The axial structures in the tail of the larval lamprey seem to differentiate from the prospective materials derived individually from the tail bud. The latter consists of two closely adjoined cell populations (C1 and C2). C1 is a small cell cluster located posterior to the other group (C2) and consists of loosely arranged polymorphous cells. The cell cluster extends cranially as a cell sheet on the ventral surface of C2; somites differentiate from this cell sheet. C2 is composed of cells elongated mediolaterally and stacked horizontally to form a compact cell mass which is covered on each lateral surface by a basal lamina. The upper one‐third of C2 seems to differentiate into the neural tube, anteceding other axial structures. The middle one‐third of C2 seems to develop into the notochord, and the lower one‐third into the subchord and the undefined cell cord. The central canal develops in the upper one‐third of C2 through the following events: (1) appearance of cilia and a small cavity between adjoining cells; (2) appearance of microvilli in the cavity, in addition to cilia; and (3) development of junctional complexes along the luminal borders of cells surrounding the cavity. Together with these events, cells surrounding the cavity increase in number, acquiring apicobasal polarity and radial arrangement. The cavity itself enlarges by incorporation of periciliary clefts and fusion of cavities with each other to establish the central canal. Near the caudal end of the neural tube, the central canal is directly confluent with the connective‐tissue space through an opening in the dorsal wall of the

ISSN:0002-9106    

DOI:10.1002/aja.1001700105

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe rat adrenal medulla architecture was examined using a combination of medullary blood vessel reconstructions and transmission electron microscopy. The peripheral radicles of the central vein and the medullary capillaries of the medullary arteries were thus precisely identified in the electron microscopic observations. The observations confirmed that the peripheral segments of the central vein were sinusoidal vessels with an attenuated and fenestrated endothelial wall. No ultrastructural differences were observed between segments lined by epinephrine‐storing cells and those lined by norepinephrine‐storing cells. The findings suggest that these peripheral segments of the adrenal central vein were sites of cortical hormonal effects on the adrenal medulla. The vessel structure does not support the hypothesis that medullary chromaffin‐cell development is controlled by selective distribution of adrenal blood ve

ISSN:0002-9106    

DOI:10.1002/aja.1001700106

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

年代:1984

数据来源: WILEY

摘要:

AbstractAmine‐containing cells in the tracheal epithelium are typically of the small‐granule type (diameter approximately 100 nm). However, in the rat, another amine‐containing cell type has been identified that possesses the amine‐handling features of the APUD‐series of cells (amine precursor uptake and decarboxylation) but not the ultrastructural characteristics. It has been postulated that these cells may be related to cutaneous melanocytes. In this study, fluorescent cells were present in the laryngeal and tracheal epithelial lining of adult Sprague‐Dawley rats following freeze‐drying and exposure to formaldehyde vapor (FIF or formaldehyde‐induced fluorescence). Microspectrofluorimetry revealed an emission maximum at 493 nm. The excitation maximum could not be calculated but appeared to be around or below 350 nm (to record spectra below requires the use of quartz optics). Yellow fluorescence also emanated from serotonin‐containing mast cells (excitation and emission maxima: 401/515 nm). Tracheal segments processed according to the aqueous formaldehyde (AFIF) technique, for the demonstration of 5‐hydroxytryptophan (5‐HTP) or serotonin (5‐HT), failed to identify fluorescent cells in the epithelial lining even though connective‐tissue mast cells were evident. Subsequent treatment of AFIF‐fixed sections with formaldehyde and HCl vapors (AFIF‐HCl) resulted in the formation of a fluorogenic compound within numerous cells in the tracheal lining (455/537 nm). This spectral shift and increase in intensity of fluorescence following acidification are characteristic for standards and/or cells that contain tryptamine, tryptophan, or peptides with NH2‐terminal tryptophan and are markedly different from microspectrofluorimetric data reported for the phenylethylamines or serotonin. It is therefore postulated that these cells contain a closely related β‐(3‐indolyl) ethylamine‐like compound, serotonin excluded.The morphology of the fluorescent cells was similar when prepared according to the FIF or AFIF‐HCl techniques. Conjunctive staining, the examination of a single section first by fluorescence microscopy and subsequently by other histochemical and cytochemical methods, demonstrated that the fluorescent granules were also methylene blue, alcian blue, periodic‐acid Schiff, and ferricferricyanide positive. Subsequent correlative electron microscopic examination of Epon‐embedded AFIF‐HCl‐treated tracheal sections demonstrated that thes

ISSN:0002-9106    

DOI:10.1002/aja.1001700107

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

年代:1984

数据来源: WILEY

摘要:

AbstractPituitary gonadotropes were identified throughout the year in the seasonally breeding, hibernating batMyotis lucifugus lucifugusby means of light microscopic immunohistochemistry. In both male and female bats, these cells were immunoreactive with an antiserum directed to the β subunit of luteinizing hormone. Some gonadotropes were aggregated near a portion of the infundibular stalk which crosses the anterior lobe, while most were scattered singly in a uniform manner throughout the rest of the pars distalis. This cell population exhibited seasonal variations in both sexes. In males, the proportional volume of the pars distalis occupied by immunoreactive gonadotropes (volume fraction) was significantly reduced in late July, when plasma testosterone levels were approaching their seasonal peak. In females, the volume fraction declined in April, following ovulation, and remained low during pregnancy and lactation. The size and shape of gonadotropes appeared relatively constant throughout the annual reproductive cycle in male bats; the immunoreactive cells were irregular in shape, with cytoplasmic extensions insinuating between and often “cupping” other secretory cell types. In females, the gonadotropes resembled those of males throughout most of the year, except during pregnancy, when these cells became enlarged and ovoid. No evidence of involution was observed in these anterior pituitary cells in either males or females during hiberna

ISSN:0002-9106    

DOI:10.1002/aja.1001700108

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

年代:1984

数据来源: WILEY

摘要:

AbstractThree groups of weanling rats and three groups of juvenile rats were fed diets which differed in physical consistency for periods of 5 and 8 weeks, respectively. In both the weanling and juvenile rats, one group was fed a soft diet, a second group was fed a hard diet, and a third group was initially fed the soft diet and then was switched to the hard diet for the remainder of the experimental period. The effects of these differences in dietary consistency on gross and histologic morphology of the craniofacial region were examined. Significant differences were found in the dimensions and morphology of the condyle and condylar cartilage as a result of the differences in dietary consistency in both the weanling and juvenile groups. Soft‐diet rats generally had smaller condyles and a thinner layer of condylar cartilage than either hard‐diet or soft/hard‐diet rats. Little change, however, was found in the overall dimensions of the mandible and maxilla in any of the groups of

ISSN:0002-9106    

DOI:10.1002/aja.1001700109

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

年代:1984

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001700101

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

年代:1984

数据来源: WILEY