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Biomedical subjects

J Brown

Publications and source records attributed to J Brown.

At least 559 records · Page 31Linked to original sources
PubMed1993

HLA antigen frequencies in renal transplant recipients and non-immunosuppressed patients with non-melanoma skin cancer.

An increased frequency of human leukocyte antigen (HLA)-DR1 was found in 49 non-immunosuppressed patients with non-melanoma skin cancer (NMSC), being highest in patients under the age of 60 with multiple squamous cell carcinomas (SCC). Of 266 patients receiving long-term immunosuppression following renal transplantation 46 (17%) were found to have NMSC. No increase in HLA-DR1 was found in renal transplant recipients (RTR) with non-melanoma skin cancer (RTR+C) when compared with matched renal transplant recipients without skin cancer (matched RTR-C), or when compared with healthy controls. There was an increased frequency of DQw2 in RTR+C, most pronounced in RTR with SCC (61.9% compared with 18.75% in matched RTR-C), giving a relative risk of 13.98. We found statistically significant differences in the frequency of a number of HLA antigens on comparing RTR+C with healthy controls, but none of these differences were found when we compared RTR+C against matched RTR-C.

Antigens, Neoplasm↗
PubMed1993

Occurrence of oocysts of Cryptosporidium sp. in Larus spp. gulls.

Between November 1990 and February 1991 101 gull faecal samples, collected in central Scotland, and 50 cloacal lavages, from gulls captured at two refuse tips near Durham, England were examined for the presence of Cryptosporidium sp. oocysts. Five of 101 (c 5%) of faecal samples and 11 of 50 (22%) of cloacal lavages contained oocysts, of which 64% and 83%, respectively were considered viable when examined with propidium iodide and 4'-6-diamidino-2-phenylindole. Since there is insufficient evidence to ascribe these oocysts to a recognized species they are therefore referred to as Cryptosporidium sp. oocysts. There were significant differences in the occurrence of oocysts between gulls captured at the different refuse tips (P < or = 0.01), but no significant difference between the distribution of oocysts in two species of gull, Larus argentatus (Herring Gull) and L. ridibundus (Black-head Gull). The differences may be explained by different food sources and feeding habits. The contribution of gulls to environmental contamination with Cryptosporidium sp. oocysts is probably generally small, but may be more significant when large numbers roost on surface waters.

Animals↗
PubMed1993

Early increase in glomerular leucocyte number after a reduction in renal mass: implications for the pathogenesis of glomerulosclerosis.

1. Adult female Wistar rats underwent uninephrectomy (n = 8) through a flank incision, or a sham operation (n = 7). One to two weeks later the kidney was perfused in situ and glomeruli were isolated from cortical tissue by sequential sieving, and partially digested. Glomerular leucocytes were labelled with a mouse monoclonal antibody against leucocyte common antigen followed by a fluorescein-labelled anti-mouse immunoglobulin to allow counting. 2. In a further group of animals 24 h albumin excretion and glomerular size were measured 2 weeks after either uninephrectomy (n = 6) or sham operation (n = 6). 3. Glomerular leucocyte number was significantly increased in uninephrectomized animals (15.7 +/- 0.9 versus 8.9 +/- 0.4, P < 0.001), with some glomeruli having leucocyte numbers comparable with those seen in glomerulonephritis. 4. Albuminuria was not increased 2 weeks after uninephrectomy (233 +/- 35 versus 170 +/- 42 micrograms/24 h, not significant), and glomerular size was unchanged. Light microscopical appearance was normal. 5. An increase in glomerular leucocyte number is an early response in what was previously considered a non-immunological lesion. It precedes the development of renal scarring and may be important in the pathogenesis of this process.

Albuminuria↗
PubMed1993

Effects of acid loading on serum amino acid profiles and muscle composition in normal fed rats.

1. Impaired body growth, loss of lean body mass and negative nitrogen balance are common findings in chronic renal failure. Enhanced endogenous protein catabolism in skeletal muscle induced by co-existent metabolic acidosis seems to be an important aetiological factor. 2. In uraemic patients abnormalities in blood amino acid profiles are present after a protein meal, suggesting impaired metabolism of ingested proteins. 3. This study demonstrates that acidosis induces changes in arterial amino acid profiles in fed non-uraemic rats. These included increased levels of threonine, histidine, proline, serine and glycine, and decreased levels of tryptophan. These changes are similar to those found in uraemic patients after a protein meal, suggesting a pathogenic role of acidosis in the impairment of exogenous protein metabolism. 4. Intracellular amino acid levels in the muscle tissue partly reflect the changes in the extracellular level. 5. Acidotic animals had a decreased body weight gain and a reduced alkali-soluble protein/DNA ratio in muscle cells compared with controls. 6. In conclusion, the results show that acidosis per se modifies the circulating amino acid profile in fed rats, resulting in a pattern similar to the post-prandial amino acid changes described in uraemic patients. These abnormalities occur together with impaired growth of skeletal muscle cells.

Acidosis↗
PubMed1993

Sequence variation in the large envelope glycoprotein (E2/NS1) of hepatitis C virus during chronic infection.

Sequence variation in the putative large surface glycoprotein (E2/NS1) of hepatitis C virus (HCV) was analyzed over 18 months in 4 patients with chronic relapsing non-A, non-B liver disease, of whom 2 were treated with lymphoblastoid interferon-alpha. Sequence analysis showed marked heterogeneity between isolates from different patients at the hypervariable region mapping to the amino-terminus of E2/NS1 (amino acid position, 386-411) and the extended sequence analyzed again confirmed the existence of two types, HCV1 and HCV2. Sequential nucleotide analysis of the hypervariable region over 1 year for each patient showed 0-9 amino acid changes, more common in the untreated than in the interferon-alpha-treated patients (3 and 9 vs. 1 and 0). Peaks of raised serum transaminases in individual patients showed no consistent association with mutations within this region. However, results do not exclude the possibility that viral persistence may be due to the emergence of "escape mutants" in the hypervariable region.

Adult↗
PubMed1993

Patient protocols.

Explore the source record for details and available documents.

Clinical Protocols↗
PubMed1993

Linkage analysis in a family with complete type congenital stationary night blindness with and without myopia.

A family is described with X-linked congenital stationary night blindness of the complete type (CSNB1) in which clinical variation between affected males resulted in diagnostic difficulties. In two affected male cousins, one had congenital nystagmus and myopia, while the other was initially thought to have retinitis pigmentosa with optic atrophy and was hyperopic. The diagnosis of X-linked congenital stationary night blindness was established by clinical, psychophysical and electrophysiological criteria, and DNA markers flanking the CSNB1 locus were analysed in the family. The results show that both affected males have inherited the same haplotype from their carrier mothers, excluding the possibility that a myopia gene in linkage disequilibrium with CSNB1 has recombined with this locus.

Adolescent↗
PubMed1993

Familial progressive supranuclear palsy.

A progressive extrapyramidal syndrome and dementia occurred in three members of one family. The age of onset was in the seventh decade and the affected individuals showed many of the clinical features of progressive supranuclear palsy (PSP). Necropsy of one individual revealed the neuropathological features of PSP. We propose that this family has a familial form of PSP and review the evidence in the literature that a familial form exists.

Aged↗
PubMed1993

C-type natriuretic peptide and atrial natriuretic peptide receptors of rat brain.

Natriuretic peptide receptors in rat brain were mapped by in vitro autoradiography using 125I-labeled [Tyr0]CNP-(1-22) to bind atrial natriuretic peptide receptor (ANPR)-B and ANPR-C receptors selectively, and 125I-labeled alpha-ANP to select ANPR-A and ANPR-C receptors. Des-[Gln18,Ser19,Gly20,Leu21,Gly22]ANP-(4- 23)-amide (C-ANP) was used for its selectivity for ANPR-C over ANPR-A. Specific binding of 125I-[Tyr0]CNP-(1-22) with a dissociation constant (Kd) approximately 1 nM occurred in olfactory bulb, cerebral cortex, lateral septal nucleus, choroid plexus, and arachnoid mater. This binding was abolished by C-type natriuretic peptide [CNP-(1-22)], alpha-ANP and C-ANP, and conformed to ANPR-C. 125I-alpha-ANP bound to all structures that bound 125I-[Tyr0]CNP-(1-22). This binding was also inhibited by both CNP-(1-22) and C-ANP, confirming the presence of ANPR-C-like binding sites. However, ANPR-C-like binding sites were heterogenous because only some had high affinities for 125I-[Tyr0]CNP-(1-22) and CNP-(1-22). 125I-alpha-ANP also bound sites without affinities for C-ANP or CNP-(1-22). These sites were consistent with ANPR-A. They occurred mainly on the olfactory bulb, the choroid plexus, and the subfornical organ. Guanosine 3',5'-cyclic monophosphate production was strongly stimulated by alpha-ANP but not by CNP-(1-22) in olfactory bulb. Neither ligand stimulated it in cortical tissue. Thus the natriuretic peptide binding sites of rat brain conformed to ANPR-A and to heterogenous ANPR-C-like sites. No ANPR-B were detected.

Animals↗
PubMed1993

Evaluation of limb symmetry indices, using ground reaction forces in healthy dogs.

Limb symmetry was evaluated by measuring ground reaction forces in 2 groups of normal-gaited dogs at a trot. Data were collected from 2 groups of 21 dogs trotted at dog/handler velocities of 1.25 to 1.55 m/s and 1.85 to 2.05 m/s, respectively. Of these dogs, 9 participated in both groups to allow comparison of data at both velocities. Additionally, 16 of the dogs in group 1 were measured in 2 directions of movement to determine whether directional dependence was present. Collected data were then applied to 3 described symmetry indices. Each index was easy to calculate, but all had limitations. A major limitation was variation in magnitude of ground reaction forces measured between the different axes and the effect of this variation on precision of the derived indices. Vertical ground forces provided the most consistent symmetry indices, in part because of their large magnitude. The indices indicated that no dog had perfect right-to-left symmetry during a trotting gait. Statistical differences were not found in any of the measurements of directional dependence. Likewise, comparing symmetry data in dogs trotted at both velocities indicated no significant differences in any axis. However, further analysis of the data revealed the actual amount that a variance attributable to right-left limb variation was negligible. Most of the variance was attributable to trial variation. Thus, the aforementioned indices, which use nonconsecutive footfall methods to evaluate limb symmetry, actually measure principally trial variation and not limb-to-limb variation.

Animals↗
PubMed1993

Current concepts in asthma management.

This short paper investigates the effects of prophylaxis on re-admission rates at the Royal Alexandra Hospital for Children, Camperdown, New South Wales.

Asthma↗