Search PubMed⌕ Search

Biomedical subjects

J Lind

Publications and source records attributed to J Lind.

At least 109 records · Page 6Linked to original sources
PubMed1982

Early arterial lesions in infancy and childhood and ways of prevention.

Arterial lesions appear in the human vascular system early in life. In some predisposed arterial segments calcifications of the internal elastic sheets have regularly been demonstrated macroscopically in infancy and early childhood. Atherosclerotic lesions also begin in childhood, and the seeds of their later clinical manifestations are probably sown in infancy. Hyperlipemia, hypertension, and cigarette smoking represent the major risk factors of atherosclerosis and its premature development. Accordingly, the main task of pediatricians is early identification of the risk groups and their appropriate treatment, particularly of children with hyperlipoproteinemia type II and those with family history indicating a premature atherosclerotic event, hypertension, and diabetes mellitus. In most populations, however, elevated serum cholesterol levels are probably not caused by genetically determined metabolic disorders but mainly promoted by environmental factors, such as nutrition. Therefore, establishment of beneficial nutritional habits early in life may prevent the development or at least limit the extent of fatty streaks and their further transformation into fibrous plaques or more advanced atherosclerotic lesions. The education of the community, especially of parents, to the hazards of the cardiovascular risk factors must become an essential part of preventive programs directed to sound cardiovascular health. The wide individual variation of the extent of early lesions, e.g., of fatty streaking in childhood even in most homogeneous population subgroups, points to the existence of still undiscovered risk factors. Cooperative efforts between pediatric pathologists and pediatricians appear, therefore, a necessity for further progress in the evaluation of these factors and for establishing successful preventive programs.

Adult↗
PubMed1980

Effects of sugars, amino acids and inhibitors on electrolyte transport across hen colon at different sodium chloride intakes.

1. The isolated colonic mucosa from adult hens has been studied in vitro under short-circuit conditions. Colonic mucosa was prepared from hens fed either a NaCl-poor or a NaCl-rich diet. 2. The unidirectional transmucosal fluxes of chloride, K and Na were measured. For the high NaCl colon the fluxes of lysine were also measured. The effects of galactose, glucose, leucine, lysine, amiloride (10(-4) M) and acetazolamide (5 X 10(-4) M) on the short-circuit current (Isc) were examined. 3. The Isc of the high NaCl colon was stimulated by galactose, glucose, leucine and lysine in a manner which suggests that these substances were transported by the epithelium in co-transport with Na. The Isc was in most cases insensitive to amiloride (mucosal side), but moderately stimulated by acetazolamide (serosal side). The Isc was closely matched by the sum of the net transmucosal fluxes of chloride, lysine, K and Na. The effects of galactose, leucine and lysine on the Isc were maintained only when glucose was present on the serosal side of the preparations. 4. The Isc of the low NaCl colon depended on the presence of glucose on the serosal (or mucosal) side. It was not stimulated by galactose or by lysine, but leucine did stimulate when added to the mucosal solution. Adding amiloride on the mucosal side invariably eliminated or, in most cases, led to an inversion of the Isc. Acetazolamide markedly stimulated the Isc; and, when added after amiloride, acetazolamide caused the Isc to become positive again. The data on Isc and net fluxes of chloride, lysine, K and Na are consistent with the presence of a process of bicarbonate absorption or H ion secretion. 5. There is a net secretion of K across both the high and the low Na colon, which is highest in the former although both Isc and net absorption of Na are highest in the latter. 6. The results from both types of colon suggest that the transport of chloride differs with the functional status of tissues.

Amiloride↗
PubMed1980

Effects of dietary intake of sodium chloride on sugar and amino acid transport across isolated hen colon.

1. Using the isolated mucosa from the colon of the adult hen, transport of galactose, leucine and lysine was studied through measurements of influx across the brush-border membrane, unidirectional transmucosal fluxes, and of steady-state mucosal uptake.2. In hens maintained on a NaCl rich diet influx of galactose, leucine and lysine were saturable processes with well defined values for J(max) and K(t). All three substances were actively transported across the epithelium and accumulated in the mucosal tissues to steady-state concentrations several times higher than in the incubation media.3. In hens maintained on a NaCl poor diet the K(t) of the leucine influx was markedly increased and the J(max) moderately decreased, while the epithelium maintained the capability of active transepithelial transport and of establishing a steady-state tissue/medium distribution ratio well above 1. Galactose and lysine could no longer be actively transported and in the steady state their tissue concentrations did not exceed those of the medium.4. It is proposed that in the low NaCl colon the processes of galactose and lysine co-transport with Na are abolished and that the transport of galactose proceeds via a phloretin sensitive system like that described for the enterocyte of the chicken small intestine.5. In the high NaCl colon 1 mM-leucine increases the mucosa to serosa flux of lysine by a factor 2.8 without affecting the serosa to mucosa flux or the steady-state mucosal accumulation of lysine. In the low NaCl colon 1 mM-leucine induces active transepithelial transport of lysine. Assuming that the active transport of leucine is secondary to the transport of Na, leucine-induced active transport of lysine is described as a tertiary active transport.6. In the high NaCl colon the mucosa to serosa flux and the steady-state mucosal accumulation of leucine were inhibited by galactose which had no effect on leucine influx across the brush-border membrane. Leucine did not affect any of the parameters of galactose transport.

Amino Acids, Essential↗
PubMed1979

Bovine serum chitinase.

1. A glycol-chitin-splitting enzyme without lysozyme (muramidase) activity has been found in calf serum. The enzyme also degrades colloidal chitin and is thus a true chitinase, 1,4-beta-poly-N-acetylglucosaminidase, without exo-beta-N-acetylglucosaminidase effect. 2. The enzyme is purified 1000-fold by ion-exchange chromatography and gel filtration. Its optimal activity is between pH 1.5-2.0 with glycol chitin and between pH 3-6 in a rather broad optimum with colloidal chitin as substrate. The optimal stability of the enzyme is in the pH interval 3.0-6.5 when tested by incubation with glycol chitin at 50 degrees C for 60 min. The optimal temperature for the degradation of glycol chitin is 40 degrees C when assayed at pH 1.5 and 51 degrees C when assayed at pH 3.5. 3. The enzyme is activated by moderate heating at pH 6.5. The highest relative activity, 135% is reached after 45 min incubation at 30 degrees C, pH 5 or after 30 min at 40, pH 2.4. By incubation with small amounts of trypsin at pH 6.5 at 3m degrees C the enzyme was temporarily activated. 4. The isoelectric point, pH 5.3, and the molecular weight, 47,000 +/- 3,000 were determined by respectively isoelectric focusing and gel filtration. 5. The Michaelis-Menten constant, Km = 0.76 +/- 0.05 (S.E.) mg/ml, was measured with glycol chitin as substrate.

Animals↗
PubMed1978

Structure and closure mechanism of the human umbilical artery.

The structure of the fully-patent umbical artery and rearrangement of its structural elements with postnatal closure were examined 10 centimeter long umbilical cord segments which were double-clamped at different time intervals after delivery. The fully-patent umbilical artery consists of two main layers: an outer layer of circularly arrange smooth muscle cells and an inner layer which shows rather irregularly and loosely arranged cells embedded in abundant metachromatic ground substance. No predominantly longitudinal arrangements of cells and fibers reported by earlier investigators could be identified in the inner layer. Closure of the umbilical arteries is initiated by numerous localized contractions which are mainly formed by muscle cells of the outer circular layer. Ultimate closure of larger segments of the umbilical arteries is also mainly produced by contractions of the outer layer. In contrast, the inner layer (which is rich in ground substance) seems to serve mainly as a plastic tissue which can easily be shifted in an axial direction and then folded into the narrowing lumen to complete closure. Electron microscopy reveals that the cells of this layer represent rather poorly differentiated smooth muscle cells which contain only a few tiny myofilaments and can therefore hardly contribute actively to the process of closure.

Cell Differentiation↗
PubMed1977

Closure of the human umbilical artery: a physiological demonstration of Burton's theory.

30 umbilical cords of normal full-term infants were examined immediately after birth for closure of the arteries. Multiple constrictions were observed in the arteries at birth, which increased in number and degree with time. Between the constrictions there were segments of dilatations with trapped blood. Cutting through the constrictions in the cords clamped later than 1 min after birth did not result in leakage of blood from the adjoining dilated segments which contained trapped uncoagulated blood indicating complete closure. This behavior of the vessels is a physiologic example of critical closure of small arteries according to Burton's theory.

Humans↗
PubMed1977

Effect of early and late cord clamping on the systolic time intervals of the newborn infant.

The effect of early and late cord clamping on the left ventricular performance of the newborn infant was assessed by measuring the systolic time intervals from the indirect carotid pulse tracings and simultaneous phonocardiogram and electrocardiogram. The study was performed in 13 normal, full-term infants sequentially at 20-105 min, 6-6 1/2 hrs, and 24-27 hrs of age. The umbilical cords were clamped early in 7 (E.C.) and clamped late in 6 infants (L.C.). The ratio of the pre-ejection period (PEP) to the left ventricular ejection time (LVET) was found to be significantly higher in the L.C. infants (mean +/- S.E., 0.400 +/- 0.18, 0.433 +/- 0.018, 0.410 +/- 0.021) compared with those of the E.C. (0.334 +/- 0.010, 0.347 +/- 0.009, 0.361 +/- 0.007) with p values of less than 0.01, less than 0.005 and less than 0.05, respectively in the three examination periods. The higher PEP/LVET ratios in the L.C. infants were mainly attributable to a prolongation of the PEP. It is suggested that late cord clamping, by allowing a sizable placental transfusion, appeared to affect adversely the left ventricular performance of the neonate. Furthermore, it is suggested that in evaluating systolic time intervals of the neonate during the first days of life, the volumic state or status of placental transfusion should be taken into consideration as a determinant.

Female↗
PubMed1977

Eleventh Edgar Mannheimer Lecture. Human fetal and neonatal circulation. Some structural and functional aspects.

Normally the neonatal circulation adjusts itself gradually during the first days of extrauterine life. The different closure rates of the major fetal vascular channels (umbilical vessels, ductus venosus, ductus arteriosus, and foramen ovale) permits smooth alterations in direction and size of shunts, should the balance of vascular resistance and pressure become upset. The study of the influence of placental transfusion on the cardio-respiratory adaptation has again demonstrated the great capacity of the transitional circulation to cope with all the strains involved in the reorganization of the circulatory system at birth. Such a capacity proves the existence of an effective system of integrated baroreceptor--and chemoreceptor--reflexes (peripheral and central).

Animals↗
PubMed1976

Chitinase and beta-N-acetylglycosaminidase in the digestive juice of Helix pomatia.

A beta-N-acetylglucosaminidase from Helix pomatia digestive juice was separated and partly purified by gel chromatography. The optimal pH for the degradation of p-nitrophenyl-N-acetyl-beta-D-glucosaminide was 3.4. The molecular weight was around 160 000 and the pI = 4.95. In the same gel chromatography run two chitinase active peaks were also obtained. These chitinase active peaks were also obtained. These chitinases, with molecular weights around 26 000 and 13 000, had somewhat different pH activity curves with optima at 4.2 and 4.3. By isoelectric focusing the first peak with molecular weight around 26 000 was divided in two chitinase active regions with pI at 5.7 and 3.5. The second peak with molecular weight around 13 000 had a pI at 7.3.

Acetylglucosaminidase↗
PubMed1975

[Family birth].

Explore the source record for details and available documents.

Family Planning Services↗