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Biomedical subjects

G Abraham

Publications and source records attributed to G Abraham.

At least 127 records · Page 7Linked to original sources
PubMed1989

Artificial nerve graft compared to autograft in a rat model.

A study was made to compare the regeneration of rat peroneal nerve across a 0.5 cm gap repaired with a sutured autograft (SAG) versus an artificial nerve graft (ANG). The ANG model is composed of a synthetic biodegradable passive conduit made of polyglycolic acid (PGA) and a synthetic growth medium composed of hypoallergenic collagen. Axonal regeneration in short-term animals (1 and 4 months) was evaluated by qualitative histology only, while in long-term animals (17 to 21 months) quantitative histology and electro-physiology were used in addition to qualitative histology. This study reveals that axons do regenerate through this ANG model, but electrophysiological analyses show that the axonal regeneration is statistically inferior to that in the SAG. There was no significant statistical difference in the quantitative histological data.

Animals↗
PubMed1989

Changes in peritoneal membrane transport rates in patients on long term CAPD.

Peritoneal equilibration tests (PET's) are a simple means of monitoring peritoneal membrane function in C.A.P.D. patients. Findings on initial testing have been proposed as having prognostic value for a patient's course on peritoneal dialysis. 177 serial P.E.T.'s were performed in 49 patients at six monthly intervals using a 2 litre 4.25% dextrose exchange and a four hour dwell and equilibration ratios were calculated for urea (D/P U), creatinine (D/P C) and glucose (D/Do G). Alterations in equilibration ratios with time were not significant in the group as a whole. However, a subgroup of 12 patients was identified in whom there were significant increases in D/P U (p .02) and in D/P C (p .003) and decreases in D/Do G (p .025) between zero and 18 months. A subgroup of five patients in whom D/P U decreased significantly (p .05) was also identified. These subgroups did not differ significantly in clinical characteristics although peritonitis was more frequent in the group with increasing transport. As results of P.E.T.'s alter with time in many patients prognostication based on initial values only may not be valid.

Adolescent↗
PubMed1989

Cause and prognosis of acute renal failure in Kuwait: a 2-year prospective study.

At the Mubarak Al-Kabeer University Hospital of Kuwait (Arabian Gulf), 77 episodes of acute renal failure were collected prospectively over 2 years, yielding a mean annual incidence rate of 9.5/100,000 population. Forty-four episodes occurred in hospital, a rate of 1.3 per 1000 admissions. In this group, acute tubular necrosis was the commonest cause (27 episodes). Thirty-three episodes occurred in the community, acute tubular necrosis accounting for 11 episodes. In contrast to hospital-acquired renal failure there was a tendency for increased incidence of community-acquired renal failure in the summer months. A more striking observation was the lower mortality in the community-acquired form. The mortality was not related to severity of renal failure even within the group with acute tubular necrosis.

Acute Kidney Injury↗
PubMed1988

Characterization of human rhinoviruses displaced by an anti-receptor monoclonal antibody.

The attachment of rhinoviruses to cellular receptors was studied by displacing bound virus particles with an anti-receptor monoclonal antibody. The two serotypes studied differed significantly with respect to the temperature dependence of displacement and the nature of the particles displaced. Binding was shown to be a two-step process, the first of which is reversible and is seen when viruses are bound either to isolated cell membranes or to cells at lower than physiological temperatures. Second-stage binding was seen with serotype 14 when bound to intact cells. Viral particles released from such cells by incubation at 37 degrees C or by anti-receptor antibody exhibited altered physical changes in the capsid and a loss of infectivity. In contrast, serotype 67 bound efficiently to cells at 37 degrees C and did not elute spontaneously but could be displaced by anti-receptor antibody to produce complete, infectious particles. Rhinoviruses labeled with [3H]myristic acid or with [35S]methionine were displaced similarly from cells or membranes by anti-receptor antibody, indicating that the majority of VP4 of rhinoviruses does not enter or remain attached to cells during either the first or second stage of virus binding. These data support the conclusion that the myristic acid moiety of VP4 is not involved in the initial viral interaction with cellular receptors.

Antibodies, Monoclonal↗
PubMed1988

Hyperglycemia after intense exercise in IDDM subjects during continuous subcutaneous insulin infusion.

Exercise is conventionally considered a modality for improvement of glycemia in diabetes. We have found that a short period of intense exercise (80% VO2max) in normal lean subjects produces sustained postexercise hyperglycemia 20% above basal with a corresponding 100% increase in plasma insulin. In people with insulin-dependent diabetes mellitus (IDDM) incapable of this insulin response, it was predicted that postexercise hyperglycemia would be of greater magnitude and/or duration. To investigate this possibility, the effects of the same intense exercise (80% VO2max) were studied in 8 IDDM subjects (2 on 2 occasions) in the postabsorptive state with continuous subcutaneous (abdominal) insulin infusion (CSII). When the preexercise plasma glucose was normal (n = 6, 86 +/- 4 mg/dl), there ensued a postexercise hyperglycemia to 127 +/- 7 mg/dl (P less than .001) sustained for 2 h postexhaustion. Plasma free immunoreactive insulin (IRI) was 1.43 +/- 0.12 ng/ml before exercise and did not change postexercise. When mean preexercise plasma glucose was 149 +/- 9 mg/dl (n = 4), it rose progressively throughout the 2 h of recovery to 229 +/- 28 mg/dl (P less than .025). A small but statistically significant decrease in free IRI occurred during the last 80 min of recovery. Hyperglycemia in the diabetic subjects was not explained by abnormal or differing responses of glucagon or catecholamines. Thus, with intense exercise, diabetic control deteriorates rather than improves. Therefore, different therapeutic strategies may be required for intense compared with moderate exercise in IDDM patients.

3-Hydroxybutyric Acid↗
PubMed1987

Transcription map of the African green monkey lymphotropic papovavirus.

The S1 endonuclease mapping technique was employed to characterize polyadenylated RNA molecules encoded by the African green monkey lymphotropic papovavirus (LPV) in B-lymphoblastoid cells of human origin infected with the virus. Two groups of stable transcripts of opposite polarities were identified and mapped. By analogy with other papovaviruses, these molecules were designated as "early" and "late" RNAs. The early transcripts include two RNA molecules consisting of a colinear 3' "main body" of about 1.9 kb spliced to 5' "leaders" of 0.26 and 0.60 kb, respectively. These molecules are presumably mRNAs encoding the LPV large T and small t antigens. Shorter, less abundant early RNA molecules have also been detected but have not been mapped. The late RNAs include three molecules, of which two consist of a common leader of 0.22 kb spliced to main bodies of 1.2 and 1.85 kb, respectively. The third late transcript of 2.3 kb is colinear. These late transcripts are presumably mRNAs encoding the LPV capsid proteins. A survey of the LPV DNA sequence published by M. Pawlita, A. Clad, and H. zur Hausen (1985, Virology 143, 196-211) allowed tentative assignment of the termini and splice sites of the various RNAs to nucleotides in the DNA sequence. The LPV transcription map is similar but not entirely analogous to those of polyoma virus and simian virus 40. These distinctions support a previous classification of LPV as a member of a new subgroup of the polyomaviruses.

Animals↗
PubMed1987

The effects of a constant T3 level and thermoneutrality in diet-induced hyperphagia.

Rats were thyroidectomized, then fitted with a miniosmotic pump infusing T3, thereby assuring a constant circulating level of T3. After a ten-day recovery period, they were submitted either to a chow or to a cafeteria diet. Body weight, food intake, and energy expenditure were recorded during a thirty day period. Thyroidectomized T3 supplemented rats did not exhibit hyperphagia when fed a cafeteria diet. Despite this puzzling normophagia, they still chose nutrients in a distribution similar to that of other cafeteria-fed rats and, though maintaining the same weight as chow-fed rats, increased their proportion of fatty weight compared to these rats. The relationship between energy expenditure, T3 concentration, and cafeteria diet are discussed.

Adipose Tissue↗
PubMed1987

Membranous nephropathy accompanied by angiolymphoid hyperplasia of the skin.

A 24-year-old female developed a painless swelling adjacent to the left ear. This was shown to be eosinophilic angiolymphoid hyperplasia (ALH). Three months later she developed a nephrotic syndrome. Renal biopsy revealed membranous nephropathy. This is the first non-Japanese case of dermal eosinophilic ALH and nephrotic syndrome; steroid treatment followed by surgical removal of the tumour resulted in complete remission in the renal lesion.

Adult↗
PubMed1986

Effects of a 'physiological' dose of triiodothyronine on obese subjects during a protein-sparing diet.

Twenty obese euthyroidian women followed an exclusively proteic diet for 18 days (74 g/day). Half received placebo, and half received 10 micrograms L-triiodothyronine. In the control group, as expected, mean weight loss was 7 percent of initial body weight; serum T3 and TSH decreased; rT3 increased; basal oxygen consumption diminished by 11 percent; nitrogen balance reached equilibrium at day 11. As compared to this group, the T3-treated group lost significantly more weight; serum T3 and TSH increased; rT3 decreased; oxygen consumption remained stable and nitrogen balance did not deteriorate. Thus, the physiological decrease in thyroid hormones provoked by a restricted diet is linked to energy expenditure but not to nitrogen balance equilibrium.

Adult↗
PubMed1984

Mapping of polyadenylated transcripts of a monkey lymphotropic papova virus.

Polyadenylated transcripts of a monkey lymphotropic papovavirus (LPV), which can be propagated in monkey and human lymphoblastoid cell lines, were identified and mapped. Polyadenylated RNA was purified from cells of the human line BJA/B infected with LPV, and was hybridized with various LPV DNA fragments. The hybrids were treated with S1 endonuclease and analyzed by alkaline gel electrophoresis. This analysis revealed two groups of RNA molecules encoded in two regions of the LPV genome. One group includes four colinear transcripts of 2.3, 2.1, 1.85, and 1.2 kb, whose polyadenylated termini map at a single site on the LPV DNA. The second group includes two less-abundant transcripts of 1.8 and 1.95 kb. The polarities of the LPV transcripts were determined by hybridizing cDNA complementary to their 3' termini with LPV DNA fragments. The two groups were found to have opposite polarities. It is shown that the four major transcripts can be aligned with, and may be functionally related to, SV40 and polyoma virus "late" mRNAs. It is also inferred that the 1.8- and 1.95-kb RNA species may be functionally related to the "early" transcripts of these papovaviruses.

Animals↗
PubMed1984

Many rhinovirus serotypes share the same cellular receptor.

Twenty-four human rhinovirus serotypes were grown and purified by centrifugation in metrizamide density gradients. These preparations had a lower buoyant density (1.24 g/cm3) and higher specific infectivities (1:24 to 1:240) than did rhinoviruses described previously (E. J. Stott and R. J. Killington, Annu. Rev. Microbiol. 26:503-524, 1972). Binding conditions in which the unique cellular receptors for virus attachment were saturated were determined for each serotype. Competition binding assays between pairs of serotypes allowed 20 of the 24 serotypes to be assigned to the same cellular receptor. The remaining four serotypes appeared to attach to a different cellular receptor. Since most serotypes were chosen for study at random, it seems likely that many of the yet unstudied rhinoviruses will share this common cellular receptor.

Electrophoresis, Polyacrylamide Gel↗
PubMed1983

Early RNA synthesis in Bunyamwera virus-infected cells.

RNA synthesis in Bunyamwera virus-infected cells was analysed either by sedimentation analysis in SDS-containing sucrose gradients or by hybridization procedures involving annealing with viral genome RNA (vRNA) followed by electrophoretic analysis. Using either procedure, none of the virus-specific RNAs from infected cells was found to be polyadenylated when analysed by oligo(dT)-cellulose chromatography. In addition, viral messenger RNA activity was found to be associated only with non-polyadenylated RNA species when assayed in an in vitro translation system. The infected cell RNAs could be partially resolved by sucrose gradient centrifugation, and virus-specific RNAs of each polarity were present in these preparations which indicated that the characteristic amplification of secondary transcription was occurring. In the presence of cycloheximide or puromycin, no detectable primary RNA transcription occurred. The same inhibitors, when used later in the infection cycle, caused a dramatic and almost complete inhibition of secondary RNA transcription. The inhibition of RNA synthesis caused by these drugs appeared to be fully reversible. Thus, these inhibitors of protein synthesis affect both primary and secondary RNA transcription by Bunyamwera virus indicating that this virus employs transcription mechanisms different from those known for other families of negative-stranded viruses. Hybridization of 32P-labelled vRNA from Bunyamwera virus with RNA extracted from virus-infected cells produced four duplex RNA molecules that were resolved by gel electrophoresis. Analysis by hybridization and oligonucleotide mapping showed that the two larger duplexes contained complementary (c)RNAs that were transcribed from the L and M segments of viral RNA while the cRNAs contained in the two smaller duplexes were both transcribed from the S RNA segment. Based on a comparison of their oligonucleotide fingerprints, the two latter cRNAs showed a considerable sequence overlap.

Animals↗
PubMed1983

Identification of four complementary RNA species in Akabane virus-infected cells.

The analysis of RNA extracted from purified Akabane virus demonstrated the presence of three size classes of single-stranded RNAs with sedimentation coefficients of 31S (large, L), 26S (medium, M), and 13S (small, S). Molecular weights of these RNA species were estimated to be 2.15 X 10(6), 1.5 X 10(6), and 0.48 X 10(6) for the L, M, and S RNAs, respectively. Hybridization analysis involving viral genomic RNA and RNA from virus-infected cells resulted in the identification of four virus-specific cRNA species in infected cells. These cRNAs were found to be nonpolyadenylated by their inability to bind to oligodeoxythymidylate-cellulose. Kinetic analysis of cRNA synthesis in infected cells at various times postinfection suggested that cRNA synthesis could be detected as early as 2 h postinfection and that maximal synthesis occurred at 4 to 6 h postinfection. The RNAs synthesized in infected cells could be partially resolved by sucrose density gradient centrifugation. The RNA fraction that cosedimented with the S segment of viral genomic RNA yielded two duplex RNA species when hybridized with viral genomic RNA, suggesting the presence of two small cRNA species. Specific hybridization with individual viral genomic RNAs confirmed that two species of cRNA are coded by the S RNA segment. Analysis of cRNA synthesis in the presence of the protein synthesis inhibitors cycloheximide and puromycin indicated that cycloheximide completely inhibited virus-specific RNA synthesis early and late in infection, whereas a very low level of synthesis occurred in the presence of puromycin. The inhibitory effects of these drugs were found to be reversible when the drugs were washed from the cells. It is concluded that continued protein synthesis is required for cRNA synthesis to proceed in Akabane virus-infected cells.

Animals↗