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Biomedical subjects

R A Anderson

Publications and source records attributed to R A Anderson.

At least 253 records · Page 14Linked to original sources
PubMed1988

Transendothelial chemotaxis in vitro of human monocytes.

Porcine aortic vascular endothelial cells were grown to confluence on microporous PTFE membranes and incorporated into a two-compartment chemotaxis assembly. Human peripheral blood mononuclear cells (20-25% monocytes) were placed in the upper compartment and zymosan-activated human serum (ZAHS) as chemoattractant in the lower compartment. Over a 3 h period monocytes migrated across the endothelialized membrane and adhered to a collecting filter sited in the lower compartment. Addition of ZAHS to the cell suspension in the upper compartment virtually abolished the migration response whilst only minimal leucocyte migration was supported by the bare unendothelialized PTFE membrane. The extent of transendothelial monocyte chemotaxis was dependent upon the concentration of chemoattractant in the lower compartment and upon the cell density of the suspension containing monocytes. A confluency test of fluid flow across the endothelialized filter showed that monocyte migration could take place without disturbing endothelial barrier function. The culture system is easy to assemble and the method provides experimental versatility.

Animals↗
PubMed1988

Tissue-specific analogues of erythrocyte protein 4.1 retain functional domains.

Analogues of the human erythroid membrane skeletal component protein 4.1 have been identified in perfused rat tissues and human T and B lymphocyte cell lines. olyclonal antibodies were used which are specific for all domains of protein 4.1, the spectrin-actin-promoting 8-Kd peptide, the membrane-binding 30-Kd domain, and the 50-Kd domain. Antibody reactivity, by Western blotting of tissue homogenates, shows reactivity with proteins varying in molecular weight from 175 Kd to 30 Kd. Further, these protein 4.1 analogues appear to be expressed in a tissue-specific fashion. Of the analogues detected there appear to be at least three classes: analogues containing all erythroid protein 4.1 domains, analogues containing all domains but with modified antigenic epitopes, and analogues containing only some domains. Chemical cleavage at cysteine linkages indicates that in analogues containing the 30-Kd region the location of cysteine is highly conserved. This datum suggests that in nonerythroid 4.1 isoforms of higher molecular weight the additional protein mass is added to the amino terminal end (30 Kd end).

Animals↗
PubMed1988

Severity of intestinal damage in gastroschisis: correlation with prenatal sonographic findings.

From 1982 to 1986, 26 abdominal wall defects were detected prenatally. Seventeen pregnancies culminated in live births with ultrasound correctly distinguishing between omphalocele and gastroschisis in all cases. In the 11 cases of gastroschisis diagnosed before birth, we attempted to correlate the clinical outcome with the size of the abdominal wall defect, sonographic appearance of the eviscerated bowel, and known time of exposure to amniotic fluid (gestational age at birth to gestational age at diagnosis). Neither the time of exposure to amniotic fluid (median duration of 14 weeks) nor the defect size could be correlated with eventual clinical outcome. The presence of small bowel dilatation and mural thickening on prenatal sonography (four patients) had a high correlation with severe intestinal damage and poor clinical outcome. The absence of these two sonographic findings (seven patients) was associated with mild intestinal changes and benign clinical course with no morbidity or mortality. We conclude that obstetric ultrasound cannot only accurately detect the presence and type of abdominal wall defect, but it also gives an indication of the severity of intestinal damage and subsequent clinical course in prenatally diagnosed cases of gastroschisis. Early delivery of the fetus with prenatally diagnosed gastroschisis should no longer be performed to limit exposure to amniotic fluid. Now that reliable sonographic criteria of severe intestinal damage have been defined, the decision to deliver early can be restricted to those fetuses with bowel dilatation and mural thickening.

Abdominal Muscles↗
PubMed1988

Exercise effects on chromium excretion of trained and untrained men consuming a constant diet.

Chromium excretion of eight trained and five sedentary men was determined on rest days and after exercise to exhaustion at 90% of maximum O2 consumption (VO2max) to determine if degree of physical fitness affects urinary Cr losses. Subjects were fed a constant daily diet containing approximately 9 micrograms Cr/1,000 kcal. VO2max of the trained runners was in the good or above range based on their age and that of the sedentary subjects was average or below. While consuming the control diet, basal urinary Cr excretion of subjects who exercise regularly was significantly lower than that of the sedentary control subjects, 0.09 +/- 0.01 and 0.21 +/- 0.03 microgram/day (mean +/- SE), respectively. When subjects consumed self-chosen diets, basal urinary Cr excretion of the trained subjects was also significantly lower than that of the untrained subjects. Daily urinary Cr excretion of trained subjects was significantly higher on the day of a single exercise bout at 90% VO2max compared with nonexercise days, 0.12 +/- 0.02 and 0.09 +/- 0.01 microgram/day, respectively. Urinary Cr excretion of sedentary subjects was not altered after controlled exercise. These data demonstrate that basal urinary Cr excretion and excretion in response to exercise are related to VO2max and therefore degree of physical fitness.

Adult↗
PubMed1987

Delayed pubertal development of the male reproductive tract associated with chronic ethanol ingestion.

Little is known concerning the sensitivity of the reproductive tract to ethanol as a function of development. The present study was conducted to evaluate the action of chronic ethanol ingestion on sexual maturation of the male. Mice were given free access to liquid diets containing 5% (v/v) ethanol for either 29 or 43 days, starting at age 20 days. Controls were given liquid diets in which isocaloric sucrose replaced the ethanol. Daily diet consumption and peak blood ethanol levels were highest during the first 2 weeks of treatment, dropping thereafter to adult levels of approximately 680 ml/kg body weight and 160 mg/dl respectively. Plasma testosterone levels were depressed by ethanol throughout treatment, the reduction being somewhat greater when measured during week 6 of treatment (average = 74% inhibition) as compared to either week 2 (36%) or week 4 (25%). Average weights of testes, epididymides and seminal vesicles were depressed by 24% (P less than 0.002), 16% (P less than 0.005) and 13% (NS), respectively, after 29 days. Testicular development was also impaired in ethanol-treated animals after 29 days. Tunica albuginea thickness and seminiferous tubule diameter were decreased (by 31%, P less than 0.05; and 16%, P less than 0.01 respectively), whereas desquamation of immature germ cells and inactive tubules were increased (325 and 780% respectively; P less than 0.01). Quality of spermatogenesis was poorer in ethanol-treated animals (P less than 0.05). Also observed were decreased sperm motility (62% inhibition, P less than 0.01) and capacity to fertilize (decreased by 67%, P less than 0.01), and an increase in the incidence of morphologically abnormal spermatozoa (by 163%, P less than 0.001). Semen volume was lower (reduced by 57%, P = 0.05), as was the total number of motile ejaculated spermatozoa (reduced by 81%, P less than 0.05). After 43 days treatment, improvement was noted in all indices of fertility except for the number of motile ejaculated spermatozoa. Significant differences persisted only for dysmorphic spermatozoa and volume and sperm count of electroejaculated semen. These data suggest that ethanol ingestion during pubertal development can delay several aspects of sexual maturation in the male.

Animals↗
PubMed1987

Effects of supplemental chromium on patients with symptoms of reactive hypoglycemia.

To determine if chromium (Cr) is involved in hypoglycemia, eight female patients with symptoms of hypoglycemia were supplemented with 200 micrograms of Cr as chromic chloride for three months in a double-blind crossover experimental design study. Chromium supplementation alleviated the hypoglycemic symptoms and significantly raised the minimum serum glucose values observed two to four hours following a glucose load. Insulin binding to red blood cells and insulin receptor number also improved significantly during Cr supplementation. These data suggest that impaired Cr nutrition and/or metabolism may be a factor in the etiology of hypoglycemia.

Adult↗
PubMed1987

An aminopterin-like syndrome without aminopterin (ASSAS).

In two patients that closely resembled the phenotype of the syndrome produced by aminopterin in early pregnancy, no evidence of maternal exposure could be elicited. These, plus two similar cases from the literature, suggest the existence of an "aminopterin-like syndrome sine aminopterin" (ASSA) syndrome. Characteristic traits are: ossification defects of the cranium, temporal recession of hairline with upswept frontal hair pattern, ocular hypertelorism, prominent nose root, low set posteriorly rotated ears, limited elbow movement, variable digital defects, simian creases, short stature, and mild to moderate psychomotor retardation. Autosomal recessive inheritance is a possibility.

Abnormalities, Multiple↗
PubMed1987

Magnesium homeostasis during high-intensity anaerobic exercise in men.

This study was conducted to determine whether short-term, high-intensity anaerobic exercise alters Mg homeostasis. Thirteen men performed intermittent bouts of treadmill running at 90% of their predetermined maximum O2 uptake until exhaustion on one occasion during a week in which all men were consuming a standard diet (115 mg Mg/1,000 kcal). Plasma and erythrocyte Mg concentrations and peripheral blood mononuclear cell Mg content were measured before and after the exercise. Complete 24-h urine collections were obtained on control days, on the day of exercise, and on the day after exercise. Exercise induced a transient but significant decrease in plasma Mg content (-6.8%; P less than 0.01); over 85% of the loss could be accounted for by a shift to the erythrocytes. Significant increases in urinary excretion of Mg were observed on the day of exercise (131.5 +/- 6.8 mg/day) compared with control days (108 +/- 6.6 mg/day), with the percent increase correlating with postexercise blood lactate concentration (r = 0.68; P less than 0.01) and oxygen consumption during recovery (r = 0.84; P less than 0.001). The data indicate that high-intensity anaerobic exercise induces intercompartmental Mg shifts in blood that return to preexercise values within 2 h and urinary losses on the day of exercise that return to base line the day after exercise. It is postulated that the exercise-induced increase in Mg excretion may depend on the intensity of the exercise, and the relative contribution of anaerobic metabolism to the total energy expended during exercise.

Adult↗
PubMed1987

The host preferences of Culiseta inornata in southwestern Manitoba.

The capillary tube precipitin test was used to determine the host utilization patterns of Culiseta inornata in southwestern Manitoba. Ruminant blood was identified in 83.3% and equine blood in 15.8% of 1,036 positively reacting blood-meals. Human, swine and avian blood accounted for 0.9% of these blood-meals and mixed blood-meals accounted for 1.5% of the total. Culiseta inornata preferentially fed on large mammals, and selection between cattle and horses reflected the relative abundance of these two hosts rather than a specific preference for either one.

Animals↗
PubMed1986

Benzodiazepine- and barbiturate-interactions with GABAA receptor responses on lactotrophs.

Modulation of the biphasic effect of muscimol on prolactin secretion by benzodiazepines and secobarbital was investigated, using an in vitro superfusion system. The stimulatory effect of low concentrations of muscimol was potentiated by both classes of drugs, and the effect of benzodiazepines appeared to be mediated by central-type benzodiazepine receptors. Neither benzodiazepines nor secobarbital affected the inhibitory response to muscimol. Clonazepam reduced the potency of bicuculline methiodide as an antagonist of the stimulatory effect, but did not alter the potency of picrotoxinin. These results demonstrate a selective potentiation of one component of the GABAA receptor effect on lactotrophs by benzodiazepines and barbiturates and provide evidence for a functional effect of these drugs at a site without the CNS.

Animals↗
PubMed1986

Distribution of GABA binding site subtypes in rat pituitary gland.

GABAA and GABAB binding sites in rat pituitary gland were investigated using equilibrium binding assays in vitro. Specific binding of both [3H]GABA and [3H]muscimol could be detected in both anterior and neurointermediate lobes, with a relative concentration in the anterior lobe. [3H]GABA binding was discriminated into GABAA and GABAB receptor type binding using baclofen. GABAB sites were detectable in the anterior but not in the neurointermediate lobe. Saturation analysis of [3H]muscimol binding to whole pituitary gland membranes demonstrated that the pituitary contains two classes of GABAA sites differing in affinity, as found in the CNS, although the number of sites is considerably lower than in the CNS.

Animals↗
PubMed1986

Prevalence and associations of apolipoprotein A-I linked DNA polymorphisms: results from a population study.

Subjects from a geographically defined population were screened for restriction fragment length polymorphisms linked to the apolipoprotein A-I (apoaA-I) gene locus. The polymorphic DNA fragments detected with an apoA-I cDNA probe after digestion with the restriction endonucleases Sac I (S1 and S2 alleles), Msp I (M1 and M2 alleles), or Pst I (P1 and P2 alleles) were used to define polymorphic haplotypes. The uncommon S2M1 haplotype was present in the leukocyte genomic DNAs of 6 of 22 (27%) subjects with high-density lipoprotein cholesterol (HDL-C) levels in the lowest decile, in contrast to none of the 20 subjects with HDL-C levels in the highest decile. With repeat determinations of the HDL-C levels 10 years later, the levels of the subjects in the low decile group with the S1M1 haplotype had regressed toward the population mean, while the regression was much less substantial for the S2M1 group. The mean triglyceride (TG) level in low HDL-C subjects with the S2M1 haplotype was also higher than in those without it (295 vs 246 mg/dl), although not all of those with the S2M1 pattern were hypertriglyceridemic. The prevalence of the P2 allele was increased in a series of men with angiographically confirmed premature coronary artery disease (CAD) (P2 present in 7 of 43) as compared to a group of age-matched controls without CAD (1 of 36). There was no difference between these groups in the prevalence of the S2 allele. These results suggest that a particular pattern of apoA-I linked genetic polymorphisms is associated with lower HDL-C levels. This type of analysis will be useful in studies of the epidemiology of abnormal lipid states and may eventually provide a genetic marker to identify those at risk can be effectively instituted.

Adult↗
PubMed1986

Effects of diets high in simple sugars on urinary chromium losses.

Thirty-seven subjects, 19 men and 18 women, consumed reference diets for 12 weeks formulated by nutritionists to contain optimal levels of protein, fat, carbohydrate, and other nutrients; the following 6 weeks, subjects consumed high sugar diets. The reference diets contained 35% of total calories from complex carbohydrates and 15% from simple sugars while the high sugar diets contained 15% complex carbohydrates and 35% simple sugars. Chromium contents of the reference and high sugar diets were both approximately 16 micrograms per 1000 calories. Compared to the reference diets, consumption of the high sugar diets increased urinary Cr losses from 10% to 300% for 27 of 37 subjects. Urinary Cr excretion of males and females was similar, and there was no significant difference in Cr absorption (calculated from urinary excretion divided by intake times 100) between sexes when adjusted for the increased caloric intake of males. These data demonstrate that consumption of diets high in simple sugars stimulates Cr losses; this coupled with marginal intake of dietary Cr may lead to marginal Cr deficiency, which is associated with impaired glucose and lipid metabolism.

Adult↗