ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Small intestinal biopsies from three patients with sucrose intolerance (sucrase-isomaltase deficiency) were studied by means of immunoelectrophoresis and enzymatic assays. All patients lacked sucrase activity (

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

A quantifiable assay is described in which the lateral cilia of the sea musselMytilus edulisare used to examine the effects of serum on ciliary function.Human sera and sera from a variety of animals have been found to induce a change in ciliary metachrony. This alteration in activity appears to be brought about by the agglutination of adjacent cilia into blocks, with the effect of increasing the wavelength; the beat frequency remains steady. Parallel studies with the rabbit cilia assay have shown the agglutination of tracheal cilia into clumps by adult bovine serum. The dilution of adult bovine serum lengthens the time before dyskinesia is first observed in both theMytilusand rabbit assays. Fetal bovine or human cord sera do not cause ciliary dyskinesia or ciliary agglutination.The evidence presented shows that the observed ciliary dyskinesia can be induced by sera from a variety of animals and is not specific to cystic fibrosis; it also suggests that the serum immunoglobulin fraction is responsible for these effects—initial studies implicate IgM.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

To investigate the regulation of actin-myosin interaction in rabbit phagocytic cells, purified myosin and a partially purified cofactor protein were obtained from polymorphonuclear leukocytes (PMN) and alveolar macrophages (ALM) by molecular sieve filtration over an agarose column. ALM cofactor enhanced the Mg++-ATPase activity of ALM myosin by actin to 0.15 × 0.04 μmoles Piper mg myosin per min and PMN cofactor enhanced PMN myosin to 0.43 × 0.03 μmoles Piper mg myosin per min. The crude cofactor preparations isolated from the two types of leukocyte extracts were interchangeable with the leukocyte myosins. When ALM cofactor was added to a PMN actomyosin complex, the Mg++-ATPase activity of the PMN myosin was 3-fold higher than with ALM cofactor and its own actomyosin complex. In contrast, PMN cofactor did not enhance ALM actomyosin Mg++-ATPase activity beyond that observed with ALM cofactor and ALM actomyosin. Cofactor protein from the PMN was further purified on a DEAE-Sephagel column. After electrophoresis on sodium dodecyl sulfate-polyacrylamide gel, the isolated fraction weighed 70,000 daltons. This fraction stimulated the actin-mediated myosin Mg++-ATPase. In the presence of Mg++and [γ32P]ATP, the 70,000 dalton protein phosphorylated the 20,000 dalton light chain of PMN myosin, leading to the incorporation of 0.62 × 0.09 moles of Piper mole myosin. On the basis of these results, we propose that phagocytic cofactor is a kinase which regulates the enzymatic activity of phagocytic cell myosin.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Pregnant rhesus monkeys (Macaca mulatta) at 67 to 85% of term pregnancy were treated with betamethasone for 3 days and then delivered by cesarean section. These treated fetuses had larger lung volumes (32.6 × 1.8 ml/kg of body weight) compared to gestational age-matched controls (22.9 × 3.2 ml/kg of body weight;P< 0.025) but no alterations in surfactant properties as measured by amniotic fluid L/S ratios, alveolar deflation stability, or lung phosphatidylcholine. These findings suggest that betamethasone effects an increase in fetal lung volume by some method other than alteration in alveolar surfactant concentrations. Results also demonstrated an 11% increase in the collagen to elastin concentration in the treated fetuses as compared to the control animals (P< 0.01), suggesting alterations in lung connective tissue. Morphometric studies done on the air-fixed inflated lung demonstrated a decrease in the number of alveoli per unit volume of lung among the treated animals (0.95 × 0.07 x 106) compared to the control animals (1.19 × 0.08 x 106;P< 0.025) and a reduction in the mean surface area of the lungs of the treated animals (506 × 10 cm2per cm3) compared to the control animals (561 × 9 cm2per cm3;P< 0.005). These findings suggest that at least part of the increased maximal lung volumes is related to increased alveolar distensibility. Together, these pressure volume findings, biochemical studies, and morphometric analyses indicate that a major effect of betamethasone on the rhesus fetal lung is to alter lung connective tissue characteristics. Alterations in lung surfactant appear to be of less functional significance in this rhesus fetal model. The disparity between these findings and other animal studies might be due to differences in species, the preparation, or the method of glucocorticoid administration.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Indirect evidence has suggested that increased quantities of antigen may penetrate the intestinal mucosa and enter the systemic circulation during the newborn period compared to adult life. However, no direct measurement of macromolecular transport has been reported as a function of perinatal age. To study this process, we administered 100 mg of tritiated bovine serum albumin ([3H]BSA) by gavage to rabbits at birth, one wk, 2 wk, 6 wk, and one year of age and measured plasma radioactivity 4 hr after gavage. Plasma concentration of trichloroacetic acid insoluble radioactivity and immunoreactive bovine serum albumin radioactivity decreased significantly after one wk of age. When adult animals were gavaged with the same amount of [3H]BSA per body weight as the one-wk-old animals, they failed to transport as much of the antigen as the younger animals. This study, therefore, provides objective evidence that the intestinal mucosal barrier of newborns may be incompletely developed at birth and allow increased intestinal transport of antigens into the circulation.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

We have recently reported that the intestinal transport of intact macromolecules into the circulation decreases with age presumably due to maturation of mucosal barrier factors. To extend this observation and determine the effect of natural versus artificial feeding on maturation of intestinal mucosal “barrier function,” we conducted experiments which assessed both macromolecular transport and epithelial cell morphology.To study barrier function, we gavage fed a physiologic quantity (100 mg) of bovine serum albumin (BSA) to weight-matched breast- and bottle-fed infant rabbits at 1 and 2 wk of age and quantitated intestinal macromolecular transport by measuring circulating plasma concentrations of the intact antigen 4 hr later. A significant decrease (P< 0.02) in immunoreactive bovine serum albumin (1-BSA) concentration was noted in breast-fed (6.12 × 0.77 μg I-BSA per ml plasma) compared with bottle-fed (9.19 × 0.93 μg I-BSA per ml plasma) animals at one wk. However, at 2 wk, no difference could be demonstrated between the two groups. Furthermore, small intestinal morphology evaluated by light and electron microscopy was similar in both groups at each age.To determine if the lower plasma I-BSA noted at one wk in naturally fed animals was related to the presence of anti-BSA antibodies in breast milk and/or in plasma of the pups, breast milk and plasma from the breast-fed animals was evaluated by counter-immunoelectrophoresis and hemagglutination. No anti-BSA antibodies were detected. Moreover, plasma from breast- and artificially fed rabbits not gavage fed BSA contained no I-BSA.These data suggest that intestinal transport of antigens in the immediate neonatal period is decreased earlier in breast- as compared to bottle-fed animals. Therefore, we suggest that breast milk may exert a protective function to control the transport of potentially antigenic molecules into the systemic circulation of newborn animals by either facilitating the early maturation of intestinal barrier function or by providing passive barrier factors until the newborn's natural barrier can develop.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

We compared the absorption of carbohydrate from solutions of glucose oligomers and glucose in jejunal Thiry-Vella fistulae, a preparation deprived of pancreatic secretions. The studies were performed with two concentrations (90 and 360 mg/dl) of both glucose and the glucose oligomers. Carbohydrate absorption from glucose solutions (33.1 × 2.8, 115.9 × 8.9 μg/cm/min) was significantly greater (P< 0.025;P< 0.005) than that from oligomer solutions (26.6 × 2.1 and 92.4 × 9.0 μg/cm/min). Thin-layer analyses of the perfusates demonstrate digestion of oligomers with a chain length up to eleven and suggest digestion of oligomers of even greater chain length. Atrophy of the jejunal mucosa occurred over the course of the study as evidenced by a decrease in the ratio of villous height to crypt depth from 3.8 to 0.3, and by a 80% decrease in the activity of maltase, sucrase, and lactase. Atrophy was accompanied by a significant decline in the absorption of both glucose oligomers (P< 0.005) and glucose (P< 0.01) from the more concentrated solutions but the decrement in absorption of both carbohydrates was similar, glucose oligomers, 79.3 × 19.4 μg/cm/min; and glucose, 69.8 × 14 μg/cm/min (P> 0.20). Water absorption was enhanced by both carbohydrates, but there was no demonstrable difference between solutions of glucose and glucose oligomers. The osmolality of the solutions clearly influenced water absorption (P< 0.025) but failed to effect the absorption of carbohydrates.

ISSN:0031-3998    

出版商:OVID    

年代:1981

数据来源: OVID