Spontaneous tubular (cuboidal) metaplasia of the parietal layer of Bowman's capsule in Cynomolgus monkeys (Macaca fascicularis)

Tubular (cuboidal) metaplasia of the parietal epithelium of Bowman's capsule was observed in 19 (10 males, 9 females) of 56 adult control Cynomolgus monkeys. Cuboidal epithelium replaced the normally present flattened epithelium to various degrees in animals affected. Cuboidal cells revealed an eosinophilic cytoplasm and vesicular nuclei, thus resembling proximal convoluted epithelial cells in all respects. Continuity of the cuboidal glomerular epithelium with that of the proximal tubule was occasionally observed.     

Cell junctions in the epithelium of Bowman's capsule

Summary The intercellular connections between the epithelial cells of Bowman's capsule were investigated. It could be demonstrated that typical zonulae occludentes (tight junctions) are present in the species (rat, hamster, and Tupaia) studied. Freeze-fracturing shows a network of anastomizing strands; some species variations are described. In the rat two strands are common. In the golden hamster mostly two to four and occasionally five strands occur. In Tupaia regularly three tight junction strands are found and also gap junctions associated with the zonulae occludentes. In thin sections the goniometric analysis confirms the freeze-fracturing results and reveals attachment zones of macular shape, which are classified as intermediate junctions and desmosomes. The functional role of these cell junctions observed in the epithelium of Bowman's capsule is discussed.     

Distribution of actin bundles in Bowman's capsule of rat kidney

In this study we define the distribution of actin bundle arrangement in Bowman's capsule of rat renal corpuscles. Parietal cells of Bowman's capsule were examined by conventional light microscopy, electron microscopy and confocal microscopy. Within each parietal cell individual actin bundles are arranged in a parallel fashion running the length of the cell. Computer reconstructions obtained using confocal microscopy clearly show the lengths of actin bundles to be arranged, on a capsule level, end-to-end, at angles and perpendicular to bundles in adjacent cells. The bundles stain positively for non-muscle myosin and vinculin. The presence and arrangement of actin bundles in parietal cells is consistent with a role in reinforcing capsule structure.     

Metaplasia of the parietal layer of Bowman's capsule in the human kidney: incidence in alcoholic liver disease and hypertension

This report is the second of two surveys to determine the incidence of metaplasia of Bowman's parietal epithelium in the human kidney. Human kidney sections obtained at autopsy at the Department of Pathology, University of Texas Medical Branch, Galveston, Texas, were examined with the light microscope. The kidneys were fixed in neutral formalin, sectioned at 6 microns and stained with hematoxylin and eosin. Autopsy records were consulted after kidney section examination to determine if there was any correlation between clinical disease, histopathological changes in organ systems and metaplasia of Bowman's capsule. The kidney sections represented both sexes in 8 age groups, from less than one year to 80 years. A total of 174 kidneys, representing 174 individuals, were evaluated. One hundred renal corpuscles were counted per section and the parietal layer of Bowman's capsule was classified as normal (squamous) or metaplastic (cuboidal). Of the 174 kidneys examined, 137 (79%)--79 male and 58 female--had metaplasia of Bowman's capsule. On the average, in the kidneys with the lesion, 6% of the renal corpuscles had metaplasia of Bowman's parietal layer. The lesion was present in both sexes in all age groups. The autopsy records revealed that metaplasia of Bowman's parietal epithelium was usually present with hepatic fatty changes and/or congestion. Alcoholic liver disease and hypertension represented the most frequent clinical diseases in the sample; these conditions had the highest incidence of metaplasia. Twenty-six of the 174 kidney samples were from individuals with alcoholic liver disease, all of whom had metaplasia of Bowman's capsule.(ABSTRACT TRUNCATED AT 250 WORDS)     

Phenotypic modulation of parietal epithelial cells of Bowman's capsule in culture

The origin of cobblestone-like polygonal cells (the most numerous in renal glomerular cell culture) remains controversial; they could be either dedifferentiated podocytes or parietal epithelial cells (PECs) of Bowman's capsule. Poor cellular outgrowth from glomeruli devoid of Bowman's capsule (decapsulated glomeruli) hinders podocytes being obtained without contamination of PECs in culture. Since podocytes are easily damaged during the isolation of glomeruli by the conventional sieving method, we devised a gentle isolation method without forced sieving, resulting in substantial numbers of arborized cells growing out from decapsulated glomeruli. The cells were distinctly different from cobblestone-like polygonal cells in their irregular and often arborized shape and extended long cytoplasmic processes that often crossed over adjacent cells. The arborized cells from decapsulated glomeruli showed intense staining for a podocyte-specific marker, podocalyxin, but no staining for markers specific to PECs (pan cadherin), mesangial cells (Thy-1) or endothelial cells (von Willebrand factor, RECA-1), indicating their podocyte origin. Polygonal cells growing out from encapsulated glomeruli were negative for podocalyxin and positive for pan cadherin at the peripheral cell-cell contact. Thus, the cell population from decapsulated glomeruli is distinctly different from that from encapsulated glomeruli, supporting the idea that polygonal cells originate from PECs, although immunocytochemical markers specific to podocytes in vivo such as WT1, synaptopodin, HSP27 and P-31 antigen were expressed significantly in the polygonal cells. Occasionally, large irregular-shaped cells appeared at the periphery of the outgrowths from encapsulated glomeruli. They were similar in shape to the arborized cells from decapsulated glomeruli but were identical in antigenic properties to cobblestone-like polygonal cells and thus may be named "pseudo-arborized cells". We conclude that PECs in culture modulate their phenotype to resemble podocytes.     

Increased incidence of isoproterenol-induced ventricular fibrillation in aging rats

Prolonged beta-adrenergic stimulation obtained by subcutaneous injection of isoproterenol in unanesthetized, unrestrained rats elicited ventricular fibrillation in approximately 80% of animals at 10-12 months of age. Ventricular fibrillation failed to occur in 1-month-old rats and involved only 12% of rats at 2 months. Senescence appeared not to increase the frequency of ventricular fibrillation since a similar incidence was seen in rats at 10-12 and 19-21 months. In all instances, ventricular fibrillation was preceded by ECG changes consistent with acute subendocardial ischemia. To evaluate whether acute beta-adrenergic stimulation elicits comparable cardiovascular effects in animals of different age, a dose-response curve to intravenous injection of isoproterenol was performed in anesthetized rats. Changes in heart rate, systemic arterial pressure, left ventricular pressure, and dP/dt were not different among animal groups. It was concluded that the arrhythmogenic potential of isoproterenol may not be related to differences in cardiac beta-receptor sensitivity with age as suggested by the comparable changes in the inotropic and chronotropic actions of isoproterenol in the animal groups studied.     

In vitro and in vivo evaluation of proximal tubular acidification in aging rats

The normal aging process is accompanied by a progressive deterioration of renal function. We studied the kinetics of proximal tubular acidification of young (3 mo) and aging (22 mo) rats using in vivo and in vitro techniques. Blood acid-base parameters were similar in both groups. The maximum velocity of the Na(+)/H(+) exchange (NHE) in brush-border membrane vesicles (BBMV) showed a 72% decrease in aging compared with young rats, whereas the Michaelis constant remained unchanged. The NHE3 isoform of the Na(+)/H(+) exchanger was detected in BBMV by Western blot in both groups, and a decrease of 90% in the abundance was observed in aging rats. Micropuncture experiments with simultaneous luminal and peritubular perfusion with phosphate Ringer and continuous measurement of intratubular pH showed an acidification rate constant 34% smaller in aging compared with young rats. Proton flux was 48% lower in aging than in young rats. The present results suggest that proximal tubular acidification is impaired with aging.     

The ultrastructural organization of the basement membrane of Bowman's capsule in the rat renal corpuscle

Summary The basement membrane of Bowman's capsule (BCBM) of the rat was studied by means of a modified tissue-preservation technique for transmission electron microscopy, which avoids the usual thorough fixation in OsO₄ and applies tannic acid and uranyl acetate for staining (Sakai et al. 1986). At most sites the BCBM is multilayered, consisting of one to seven dense layers separated by electron-lucent layers. The latter, which can be termed laminae rarae, contain fine filaments which connect the dense layers to each other and the innermost dense layer to the basal cell membrane of the parietal epithelium. The laminae densae are basically composed of fine filaments arranged in an anastomosing pattern. Individual filaments ranging from 5 to 15 nm in diameter, combine to form filament bundles up to 100 nm in thickness and 1 to 2 m in length. Within a dense layer, filaments and filamentous bundles are oriented mainly in the same direction. Often the inner dense layers do not form a continuous sheet, and the filamentous bundles are arranged in anastomosing or spiral patterns to form a ribbon-like structure that we call a microligament. These microligaments are often embedded in basal furrows of the parietal epithelium and are best developed around the vascular pole. Intracellular actin bundles of the parietal cells are regularly associated with these extracellular ribbon-like structures of the basement membrane. In conclusion, the BCBM has an unusual structure: the laminae densae are characterized by their filamentous nature and are arranged in different patterns, i.e. as a multilayered mat and as microligaments.Fellow of the Deutscher Akademischer Austauschdienst     

铁皮石斛和百令胶囊对老年SD大鼠肠道菌群的影响

目的 探讨铁皮石斛和百令胶囊对自然衰老SD大鼠肠道菌群组成和多样性的影响.方法 选取自然衰老SD雄性大鼠30只随机分为5组,分别为铁皮石斛高(400 mg/kg)、中(200 mg/kg)、低(100 mg/kg)剂量组及百令胶囊组(40 mg/kg)、空白对照组,每组6只,对各组大鼠连续灌胃8周.在灌胃结束后,取各组...     

Sex difference and fine structure on epithelium cells of Bowman's capsule in mice (author's transl)

Bowman's capsules with cuboidal epithelium were found in 87.2%, 95.5%, 75.4%, 96.7%, 98.8% and 91.2% in the kidney of adult male C57BL/6J-ob, JCL-ICR, dd, E1, ASK and KK mice, respectively, while in 57.9%, 6.7%, 7.0%, 2.8% and 9.1% in adult female C57BL/6J-ob, JCL-ICR, dd, E1 and ASK mice, respectively. The renal corpuscles with cuboidal epithelium in Bowman's capsules of male JCL-ICR mice increased gradually in number from 5 to 10 weeks age. The surface of cuboidal epithelium cells was shown to have long cilia and dense microvilli, which were similar to those seen in proximal uriniferous tubules.     

Metaplasia of the parietal layer of Bowman's capsule: a histopathological survey of the human kidney

Human kidney sections taken at autopsy were examined to determine the incidence of metaplasia of the Bowman's parietal epithelium. Autopsy records were consulted to determine if there was any correlation between clinical disease, histopathological changes in organ systems and metaplasia of Bowman's capsule. The sections represented both sexes in 9 age groups from 2 to 87 years. The sections were fixed in neutral formalin, embedded in paraffin, sectioned at 6 microns, and stained with hematoxylin and eosin. A total of 129 kidney sections, representing 129 individuals, were evaluated. One hundred renal corpuscles were counted per section and the parietal layer of Bowman's capsule was classified as normal (squamous) or metaplastic (cuboidal). Of the 129 kidneys examined, 69 (53%) had metaplasia of Bowman's capsule. Of the 87 male kidneys, 51 (59%) exhibited metaplasia of Bowman's capsule. Of the 42 female kidneys examined, 18 (43%) of the kidneys had metaplasia of Bowman's capsule. On average, in kidneys with metaplasia, 4% of the renal corpuscles had metaplasia of Bowman's parietal layer. The lesion was present in both sexes in all age groups. The autopsy records revealed that there was no common clinical condition associated with the metaplastic lesion, but metaplasia of Bowman's parietal epithelium was consistently present with hepatic congestion and/or fatty changes.     

On the role of aging in cancer incidence

All tumors classified by the Connecticut Tumor Registry which had a single peak incidence at age greater than 50 were found to have similar patterns of incidence as a function of age. The average of all such patterns was described by an equation of the form log incidence = m(age) + b, where m and b are constants. This equation suggests that the tumors in this study could all be related to a common physiological property such that the number of tumors in the population described the status of this property and the status of this property determined the number of tumors. A similar equation describes the incidence of death from all causes as a function of age. We suggest that the incidence of both cancer and death in general are related to a common physiological property and that this property is the integrity of the genome.