摘要:

SummaryHereditary nephritis (HN) is a progressive renal disease not uncommonly seen in children. Asymptomatic hematuria is an early and consistent finding with or without proteinuria. Distinctive abnormalities frequently associated with this condition involve basement membranes primarily (glomerular basement membrane, lens capsule, and possibly, tectorial membrane of the organ of Cord). These basement membranes contain collagen with similar biochemical composition suggesting that this association may be pathogenetically related. On the basis of this observation, we studied collagen metabolism in patients with HN by utilizing urinary hydroxylysine glycosides (hyl glyc) as an index of collagen metabolism. The hyl glyc hydroxylysine galactose glucose and hydroxylysine galactose are basic units in basement membrane as well as a large number of other collagen. We studied 25 normal children, seven patients with HN, and six HN siblings with hematuria. The mean excretion of total hyl glyc are 64 ± 5.5, 93 ± 14, and 123 ± 15.6 umoles/g creatinine, respectively. The difference in the mean excretion level of total hyl glyc between patients with HN and normal controls is statistically different (P< 0.05). The siblings of HN patients differed significantly from normal (P> 0.005), but was comparable to the HN patients. Two of 16 additional patients studied had the Nail Patella syndrome and showed increased urinary hyl glyc. The elevated urinary hyl glyc in HN patients and their siblings strongly suggests an altered rate of collagen degradation during the natural course of the disease. The origin of collagen is presently unknown because no data exists describing the biochemical composition of basement membrane collagen in HN. To elucidate further the pathogenesis of this important disease, studies should investigate the biosynthesis and metabolism of basement membrane collagen of involved structures.SpeculationCollagen metabolism in HN suspect patients will raise the index of suspicion if found to be altered. This observation may provide increased understanding of the pathogenesis of this disorder.

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryThe surfactant depleted adult rat lung model previously reported by us was used to determine the ability of certain phospholipids (PL), either singly or in combination, to restore the lung pressure-volume (PV) characteristics to normal. Seventy-one adult rats were used for this study. Before depletion of surfactant, a PV curve was obtained and the mean percent total lung capacity (% TLC) at 5 cm H2O on the deflation limb was 53.8. Maximal removal of surfactant was done by repeated lung washings, and a second PV curve was obtained (mean % TLC was 9.2). Various PL suspensions were prepared by sonication of dipalmitoyl lecithin and another PL in saline at a molar ratio of 9:1. The final concentration was 5 mg DPL/ml. Each suspension was instilled directly into the trachea and the lung was ventilated for 5 min at a rate of 40/min, a volume of 7 ml, PEEP of 5 cm H2O, and an inspiration to total cycle ratio of 0.4. A third PV curve was then done. For all PV curves, the percent of original TLC at 5 cm H2O was calculated. The % TLC at 5 cm H2O after treatment with phospholipid suspensions, showed: DPL/unsaturated phosphatidyl glycerol (u-PG), 37.2; DPL/unsaturated phosphatidyl inositol (u-PI), 28.3; DPL, 25.8; DPL/unsaturated phosphatidyl serine (u-PS), 25.7; DPL/unsaturated lecithin (u-Lecithin), 24.1; DPL/dipalmitoyl phosphatidyl glycerol (DPPG), 7.7; and an analog of DPL from the University of Rhode Island (URI analog), 20.1. Although six of the seven suspensions possessed varying ability to restore the PV characteristics toward normal, none was as effective as natural surfactant which gave a mean of 46.8.SpeculationOf the seven phospholipid mixtures, DPL/u-PG produced the most improvement in lung stability. Furthermore, surface tension measurements of DPL/u-PG showed normal surface activity. This suggests that DPL in combination with u-PG might afford a basis for development of a synthetic surfactant for treatment of respiratory distress syndrome (RDS).

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SUMMARYOleic acid uptake and esterification in intact intestinal mucosa were studied in 14 infants and children with chronic non-specific diarrhea, but histologically normal small intestinal mucosal biopsies, using an in vitro technique. The uptake rate was 5.876 ± 1.942 nmol fatty acid/mg Nitrogen/minute and the esterification rate was 4.060 ± 1.010 nmol fatty acid/mg Nitrogen/minute, comparable to previous adult esterification studies. No effect of age on either esterification or uptake was present. Mucosal injury resulted in significant reductions in esterification (p < 0.001) and uptake (p < 0.05) compared to controls. Bile acid deficiencies led to reductions in mucosal esterification (p < 0.05) but not uptake.SPECULATIONThe intestinal mucosal biopsy has been an invaluable tool in the study of the histopathology and ultrastructural pathology of human disease; it will become a valuable tool to study intestinal biochemistry, enzymblogy and physiology. The simplein vitroincubation technique described, with application to the study of fatty acid uptake and esterification and to other areas of mucosal metabolism, may allow delineation of new etiologies for chronic infantile diarrhea. Specific alterations in mucosal metabolism may be found associated with alterations in intestinal mucosa morphology or intraluminal conditions.

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SUMMARYGlucose biokinetics were assessed simultaneously in the pregnant ewe and its fetus by a primed constant infusion of 2-1H glucose and U-1C glucose. Late in gestation fetal glucose turnover was 27.3 ± 3.7 mg/min; expressed in terms of fetal weight this is 6 to 10 mg/kg/min. In the fed state the results indicated that all of the fetal glucose turnover was derived from the mother via placental transfer and there was no evidence that the fetus was capable of glucose production. Maternal glucose turnover was 145.6 ± 9.3 mg/min (2.8 mg/kg/min). There was a significant amount of glucose (16.3 ± 2.3 mg/min) transferred from the fetus to the mother. This feto-maternal transfer of glucose accounted for 11% of the maternal glucose turnover and approximately 50% of the total glucose coming to the fetus from the mother. This study provides the firstin vivosimultaneous quantification of the bidirectional glucose transfer across the placenta.SpeculationIn the fed state all the fetal glucose is derived from the mother, and the fetus does not produce glucose. A large portion of the glucose coming from the mother to the fetus is returned to the mother, despite glucose concentrations that are threefold higher in the mother than fetus. Thus, the transplacental passage of glucose is bidirectional, this bidirectionality may be responsible for maintaining the concentration gradient that always keeps fetal glucose ooncentration at a lower level than that of the mother, and thereby facilitates fetal glucose supply.

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryMelatonin was detected in the circulation of the near-term rhesus monkey (Macaca mulatto) and baboon (Papio papio) fetus. We determined whether the source could be the mother by studying placental transfer of melatonin in the rhesus monkey. When [3H]melatonin was administered i.v. to the mother it promptly appeared in the fetal circulation; the rates of disappearance of [3H]melatonin in the maternal and fetal circulations were parallel. The rapid decrease in circulating [3H]melatonin was associated with a rapid accumulation of [3H]melatonin-metabolites in the maternal and fetal circulations. Although the pattern of appearance of metabolites was similar in both circulations, relatively less [3H]melatonin-metabolites appeared in the fetal circulation.Acute changes in total maternal plasma melatonin, experimentally produced by giving a 20 min infusion of melatonin, were rapidly reflected in the fetus. This suggests that a daily rhythm in maternal melatonin would generate a similar rhythm in the fetus.The fetal monkey pineal was found to have the two enzymes necessary for the conversion of serotonin to melatonin. It is, however, not known whether fetal melatonin synthesis is rhythmic or the extent to which it could contribute to circulating melatonin levels at this or earlier stages of gestation.SpeculationPrompt placental transfer of melatonin could result in a maternally generated dally melatonin rhythm in the fetus. This communication may introduce the developing fetus to a 24-hr chemical periodicity and coordinate certain fetal functions with the prevailing environmental lighting cycles.

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SUMMARYNormal values for the percentages of lymphocytes carrying surface membrane -bound immunoglobulin, or resetting with sheep erythrocytes, ox erythrocytes coated with rabbit immunoglobulin G, or ox erythrocytes coated with rabbit immunoglobulin M and reacted with human serum partially de-complemented with zymozan, have been estimated for populations from human umbilical cord blood and the peripheral blood of babies aged one week and one month. These samples have been compared with values obtained from normal adult volunteers and eighteen newborn infants, measured during and after a suspected infective episode.The dynamic change in those lymphocytes from normal infants staining for both IgM and IgD is shown, demonstrating that the number of circulating cells of this typeapproaches adult levels by the age of one month. Falls in the levels of all three types of rosetting lymphocyte were demonstrated over the same period. A drop in the number of lymphocytes forming sheep erythrocyte rosettes, and particularly those binding C3b-coated ox erythrocytes, in those babies suspected of infection showed a correlation with acute septicaemia or viraemia.SPECULATIONThe fall in the sub-population of lymphocytes forming all three types of rosettes, with increasing age, is felt to reflect the sudden antigenic challenge experienced by the newborn infant after birth. In particular, the dramatic fall in those lymphocytes bearing immunoglobulins M and D may mark the selection of virgin antigen-sensitive B-lymphocytes in response to antigens. The fall in the proportion of lymphocytes binding to C3b-coated ox erythrocytes in infected infants may indicate either that the lymphocyte C3b receptor becomes blocked by free C3b released as a consequence of complement activation, or, more plausibly, that there are circulating antigen/antibody complexes bearing fixed C3b in these babies. Finally, it should be noted that a fall in any lymphocyte population in peripheral blood, particularly of cells binding sheep erythrocytes, may be more closely related to a segregation of those cells within the lymphoid system rather than a failure to express the relevant receptor.

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID