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Biomedical subjects

S Rogers

Publications and source records attributed to S Rogers.

At least 289 records · Page 16Linked to original sources
PubMed1984

Enhanced galactose metabolism in isolated perfused livers of folate-treated suckling rats.

Folic acid (1 mg/day) was administered intraperitoneally to seven-day-old suckling rats for a period of seven days. Livers of folate-treated animals took up galactose rapidly during the first 35 minutes of perfusion, whereas uptake was delayed in the controls (sham-injected and untreated). More glucose was released by all groups when galactose was perfused than when other substrates were used. With each hexose tested, livers of the folate group consistently released less glucose but more lactate than the controls. The specific activity of galactose-1-phosphate uridyltransferase was elevated in livers of the folate group compared to the controls perfused with either galactose or glucose. A similar finding was made for ATP levels in perfused livers of this group. The differences in transferase and ATP levels in perfused livers of folate-treated over the control groups may explain the enhanced galactose uptake pattern.

Adenosine Triphosphate↗
PubMed1984

Comparison of Cultureset and primary rabbit kidney cell culture for the detection of herpes simplex virus.

Herpes simplex virus isolation by conventional cell culture in primary rabbit kidney cells (RK) was compared with Cultureset (CS). At 24 h CS was more sensitive (31 versus 25 of 55 isolates detected) than RK, but at 48 h there was little difference (43 detected by CS, 46 by RK). CS stained at 48 h was significantly less sensitive (78.2%) than RK observed for 1 week. CS stained at 24 or 48 h was not an acceptable substitute for RK observed for 1 week.

Animals↗
PubMed1984

Insulin stimulates Pi transport in brush border vesicles from proximal tubular segments.

Induction of hyperinsulinemia in dogs results in enhanced reabsorption of Pi from glomerular filtrate in the renal proximal tubule. To determine whether this may be a direct action of insulin mediated by altered transport characteristics of the proximal tubular brush border membrane, we measured Na+-dependent 32Pi transport in brush border membrane vesicles prepared from isolated proximal tubular segments originating from dog kidney that had been incubated with or without insulin. Specific high affinity binding sites for insulin were detected in proximal tubular segments. Increased initial rates (15 s) of Na+-dependent 32Pi transport were measured in brush border vesicles prepared from segments that had been incubated with insulin. This effect of insulin was concentration dependent over the range of 10(-10) to 10(-6) M insulin. These studies demonstrate the feasibility of using brush border vesicles prepared from proximal tubular segments to study solute transport. Our findings suggest that insulin-induced increased Pi reabsorption in the proximal tubule is mediated by a direct action of insulin on the proximal tubular cell, which results in increased Na+-Pi cotransport across the brush border membrane.

Adenosine Triphosphate↗
PubMed1984

Colorimetric measurement of glycosylated protein in whole blood, red blood cells, plasma and dried blood.

A colorimetric method for the measurement of whole-blood glycosylation (WBG), glycosylated haemoglobin in red blood cells (GHb), glycosylated plasma protein (GPP) and dried-blood glycosylation (DBG) is described which is rapid, inexpensive and precise. GHb correlated well with HbA1 measured by cation-exchange chromatography and was also correlated with WBG, DBG and GPP. DBG, which showed good correlation with GHb, could be measured on several drops of blood dried on filter paper treated with glucose oxidase. Filter papers are posted to the laboratory prior to clinic visits, and by having the DBG result available more rational diabetic management is possible. For DBG, the intra- and inter-assay coefficient of variation at three levels is less than 6%. Reference values in non-diabetic children have been calculated and are compared with values obtained in 'good' clinical diabetic control and in 'fair' control. The filter-paper assay DBG method has a high degree of patient acceptance.

Blood Glucose↗
PubMed1984

IUD-associated hospitalization in less developed countries.

Data on 11,977 insertions of an intrauterine device (IUD) from 25 collaborating centers in 16 less developed countries (LDCs) were investigated for IUD-associated hospitalizations. These centers maintained regular follow-up and reported at least one hospitalization among their IUD cases. The Lippes Loop, Copper T, Delta Loop, and Delta T were the most commonly used devices, and three-fourths of all devices were inserted in postpartum women. Fifty-five of the 128 reported subsequent hospitalizations were associated with IUD use. Main indications for IUD-associated hospitalizations were pelvic infection, bleeding/pain, and method failure. Statistically significant differences were not detected in the three-month gross cumulative rates for hospitalizations due to IUD complications by age (less than 30 vs 30+), parity (0-1 vs 2+), or device type (Lippes Loop and Copper T vs Delta devices vs others). Three types of IUD-associated hospitalization rates were calculated, each involving a margin of error: 1) a Pearl rate of 8.0 per 1,000 woman-years of IUD use; 2) a one-year life table rate of 6.3 per 1,000 insertions; and 3) crude rates ranging from 3.2 to 4.6 per 1,000 cases.

Adult↗
PubMed1983

A comparison of Norinyl and Brevicon in three sites in Sri Lanka.

A set of 3 four-cell randomized, blind clinical trials was carried out in Sri Lanka to evaluate the impact of vitamin supplements and different oral contraceptive formulations. This paper concentrates on the comparisons of oral contraceptives. There seems to be no important difference between Norinyl, a standard-dose oral contraceptive, and Brevicon of a lower estrogen dosage--in either continuation or side effects. Continuation at one site was higher among Norinyl users, but several factors led us to the belief that this difference was due to differences in field worker performance rather than to the pharmacological properties of the drugs. Some differences in side effects were observable along predictable lines; breakthrough bleeding was more common among Brevicon users than Norinyl users, and most other side effects were more frequent among Norinyl users, although these latter differences were quite small, and there were several exceptions.

Adolescent↗
PubMed1983

Genome intermixing and sister chromatid exchange in newly-formed HeLa-3T3 Hybrid cells.

Mouse and human genomes occupy distinct regions within hybrid interphase nuclei following division of HeLa-3T3 heterokaryons. With subsequent cell division the proportion of interphase cells displaying separation of human and mouse genomes decreases. Examination of several hundred hybrid colonies revealed a linear relation between the log of the fraction of interphase cells with separated genomes and the log of clone size. This indicates that there is a constant probability that separated genomes will intermingle at each mitosis. Human and mouse chromosomes can also occupy distinct sectors in metaphase spreads derived from heterokaryons. Computer analysis of the distribution of chromosomes within 548 hybrid metaphases showed that mouse and human chromosomes are randomly intermixed within several divisions and before the onset of rapid chromosome loss. Sister chromatid exchange (SCE) rates were also measured in mass populations of newly-formed HeLa-3T3 hybrid cells. For most hybrid metaphases there was not significant change in SCE rates within the human chromosome set. In a small minority of hybrid metaphases, characterized by asynchronous condensation of chromosome sets, there was a 50-fold increase in SCE. However, chromosomes are progressively lost from all hybrid cells. Thus, the two processes examined in the present studies, the distribution of human chromosomes at metaphase and SCE, are not implicated in the preferential loss of human chromosomes from HeLa-3T3 cells.

Animals↗
PubMed1983

Intracellular distribution and degradation of immunoglobulin G and immunoglobulin G fragments injected into HeLa cells.

Intact rabbit immunoglobulin G molecules (IgGs) and their papain or pepsin fragments were radio-iodinated and injected into HeLa cells. Whole IgGs, Fab2, and Fc fragments were degraded with half-lives of 60-90 h, whereas half-lives of Fab fragments were 110 h. These results indicate that proteolytic cleavage in the hinge region of the IgG molecule is not the rate-limiting step in its intracellular degradation. The hingeless human myeloma protein, Mcg, was degraded at the same rate as bulk human IgG, providing further evidence that the proteolytically susceptible hinge region is not important for intracellular degradation of IgG molecules. SDS acrylamide gel analysis of injected rabbit IgG molecules revealed that heavy and light chains were degraded at the same rate. Injected rabbit IgGs and rabbit IgG fragments were also examined on isoelectric focusing gels. Fab, Fab2, and Fc fragments were degraded without any correlation with respect to isoelectric point. Positively charged rabbit IgGs disappeared more rapidly than their negative counterparts, contrary to the trend reported for normal intracellular proteins. The isoelectric points of two mouse monoclonal antibodies were essentially unchanged after injection into HeLa cells, suggesting that the altered isoelectric profile observed for intact rabbit IgG resulted from degradation and not protein modification. The intracellular distributions of IgG fragments and intact rabbit IgG molecules were determined by autoradiography of thin sections through injected cells. Intact IgG molecules were excluded from HeLa nuclei whereas both Fab and Fc fragments readily entered them. Thus, for some proteins, entry into the nuclear compartment is determined primarily by size.

Animals↗
PubMed1983

Galactose metabolism in suckling and adult isolated rat hepatocytes.

The metabolism of galactose during the postnatal developmental period has been examined in isolated parenchymal cells of livers from fasted rats aged 7, 14, 21, 28, and 42 days, by measuring the disappearance of 1 and 4 mM 1-[14C]galactose from the incubation media as well as [14C]galactose conversion to [14C]glucose and [14C]lactate and oxidation to [14CO2]. Cells from 7- and 14-day-old suckling animals consistently utilized galactose more rapidly (4 times greater) than those of adult. Hepatocytes of suckling rats also converted greater amounts of galactose to glucose and oxidized galactose 2-3 times faster than the adult. The conversion to glucose by suckling cells occurred with minor recycling of labeled C-1 galactose to C-6 of glucose. A comparison with [1-14C]glucose as substrate showed that oxidative rates by the young cells were 3 times faster for galactose than for glucose. This was not due to the presence of a direct galactose oxidative pathway as assessed by the [14CO2] yield from C-1 and C-2 labeled galactose. Incubation of hepatocytes with galactose appeared to augment the production of glucose from endogenous precursors, 33 nmoles/mg cells in 30 min. The enhanced glucose output from endogenous sources in isolated suckling hepatocytes incubated with galactose contrasts with the sugar's suppression of glucose output observed in isolated perfused liver even though galactose metabolism in both preparations are similarly greater in the suckling than in the adult.

Animals↗
PubMed1983

Failure to insert an intrauterine device.

Numerous studies have reported IUD-related events in evaluating the rates of pregnancy, expulsion, and removal for bleeding and pain, but the inability to successfully insert an IUD has been overlooked. This study analyzed data on 51 unsuccessful insertions from 22 international centers collected on standard forms. The incidence of insertion failures was estimated to be between 2.3 and 8.3/1000 attempted insertions. No statistically significant risk factors in patient characteristics were delineated through a case-control analysis. The incidence of insertion failures among postpartum cases was highest for the Delta Loop (16.8/1000 insertions). Data suggest that failure to successfully insert an IUD may not be directly attributable to any specific host characteristic but rather is contingent on agent (IUD type) and provider (inserter) factors.

Cervix Uteri↗
PubMed1982

Mutagenicity of a series of hexacoordinate cobalt(III) compounds.

15 cobalt(III) compounds have been tested for DNA-damaging capabilities using an E. coli differential repair assay and for mutagenicity in strains of Salmonella typhimurium. 4 of these compounds were active in both systems. Although the general ligand requirements for genetic activity of cobalt(III) appear to closely parallel those of chromium(III) and rhodium(III), the genetic activity of cobalt compounds seems particularly dependent upon the structure of the ligands coordinated about the metal ion. By a simple methyl substitution on the organic ligands, a compound completely devoid of activity, e.g. trans-[Co(pyr)4Cl2]Cl, could be made slightly mutagenic in Salmonella typhimurium strains e.g. trans-[Co(3-pic)4Cl2]Cl. Substitution at the 4-position rather than the 3-position on the same pyridine ring, e.g. trans-[Co(4-pic)4Cl2]Cl, results in a 50-fold enhancement of activity in both repair and mutagenesis systems. The difference in genetic activity is attributed to the influence of the ligands on the relative lability of the metal complex.

Cobalt↗
PubMed1982

A preliminary report: nutritional levels and cognitive performance in chronic alcohol abusers.

The relationship between vitamin levels, alcohol intake and cognitive status was examined in a group of 19 chronic alcoholics who had just begun to withdraw from alcohol. The results indicate that during this stage of detoxification levels of folic acid are the best predictors of cognitive performance. Alcohol intake, as measured by either total life consumption or years of alcohol abuse, was only weakly associated with neuropsychological tests scores. It is suggested that the cognitive recovery that occurs during the first weeks of abstinence may be related to nutritional variables, whereas the longer-lasting neuropsychological impairments of alcohol abusers may be related to the direct neurotoxic effects of alcohol.

Adult↗