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Biomedical subjects

D W Brown

Publications and source records attributed to D W Brown.

At least 163 records · Page 9Linked to original sources
PubMed1987

Effects of two negative staining methods on the Chinese atypical rotavirus.

The Chinese atypical (Group B) rotavirus, previously called the adult diarrhoea rotavirus (ADRV), was examined by transmission electron microscopy using either uranyl acetate or potassium phosphotungstate (PTA) as negative stains. Complete rotavirus particles were seen using uranyl acetate which were indistinguishable morphologically from typical rotaviruses. In the same preparations virus particles with differing degrees of degradation were seen after staining with PTA. This effect was not related to pH of the PTA and could be prevented by fixation of the specimen by 0.1 per cent glutaraldehyde. It is concluded that the use of PTA can give rise to falsely negative results for specimens containing this virus.

Glutaral↗
PubMed1987

Functional causes of the ductal obstructive pattern on hepatobiliary scans.

Hepatobiliary imaging with Tc-99m IDA derivatives has proven value for evaluation of biliary disease. Prompt hepatocellular uptake with persistent nonvisualization of the common bile duct and bowel is usually indicative of a high-grade common bile duct obstruction, but is not pathognomonic. A functional abnormality due to hepatocyte dysfunction resulting in intrahepatic cholestasis can also cause this pattern. Two cases of hepatocellular excretory dysfunction, one due to E. coli endotoxemia with intrahepatic cholestasis and the other due to acute hepatitis A that produces ductal obstructive patterns on Tc-99m disofenin scintigraphy in patients with documented patent biliary ducts, are reported. Transhepatic cholangiography or endoscopic retrograde cholangiography may be useful when the diagnosis of biliary ductal obstruction is in doubt.

Adult↗
PubMed1987

Prevalence of antibody to group B (atypical) rotavirus in humans and animals.

Enzyme-linked immunosorbent assays were developed for the detection of group B rotavirus antigen and antibody. The specificities of both assays were evaluated for antigens and serum specific for rotavirus groups A to D. Serum collected in the United Kingdom from different animal species exhibited the following high prevalence of group B rotavirus-specific antibody: pigs, 97%; cattle, 71%; sheep, 91%; and goats, 91%. In human serum, a lower prevalence of group B-specific antibody was detected; serum from blood donors showed 10% prevalence, and serum from veterinarians showed 4% prevalence.

Animals↗
PubMed1987

Detection of Breda virus antigen and antibody in humans and animals by enzyme immunoassay.

Enzyme immunoassays were developed for the detection of Breda virus antibody and antigen. Cattle sera collected in the United Kingdom were found to have a high prevalence of antibody (55%) to Breda virus when examined in a competitive enzyme-linked immunosorbent assay. A low prevalence of antibody was found in pigs (2.2%), and no antibody was found in sheep or goat sera. No antibody to either Breda virus or Berne virus was detected in human sera collected from veterinarians and farm workers. Only 1 of 430 human fecal specimens (0.2%) contained Breda virus antigen detectable by enzyme-linked immunosorbent assay.

Animals↗
PubMed1987

Field and laboratory studies of the etiology of liver neoplasms in marine fish from Puget Sound.

A series of field studies was conducted between 1979 and 1985 in Puget Sound, Washington State, to investigate etiological relationships between prevalences of hepatic neoplasms in bottom-dwelling marine fish species, with emphasis on English sole (Parophrys vetulus), and concentrations of toxic chemicals in sediments and affected fish. Statistically significant (p less than or equal to 0.05) correlations have been found between the prevalences of hepatic neoplasms in English sole and the following parameters: sediment concentrations of aromatic hydrocarbons, and concentrations of the metabolites of aromatic compounds in the bile of affected sole. A significant difference (p less than 0.001) was also found between the relative concentrations of aromatic free radicals in the liver microsomes of English sole with liver lesions compared to sole without liver lesions. Laboratory studies designed to evaluate the etiology of the liver neoplasms in English sole have also yielded evidence that is consistent with the view that high molecular weight aromatic hydrocarbons, e.g., benzo[a]pyrene (BaP), are hepatocarcinogens in English sole. The current status of a series of long-term (up to 18 months) exposures of English sole and rainbow trout (Salmo gairdneri) to selected fractions of Puget Sound sediment extracts, enriched with aromatic hydrocarbons and nitrogen-containing aromatic compounds, and to individual carcinogens (e.g., BaP) is discussed.

Animals↗
PubMed1986

Preliminary characterisation of torovirus-like particles of humans: comparison with Berne virus of horses and Breda virus of calves.

Pleomorphic virus-like particles have been observed by electron microscopy in the faeces of children and adults with diarrhoea. Some of these particles were approximately 100 nm in diameter and had a "fringe" of closely applied peplomers approximately 10 nm long; they closely resembled Berne virus of horses and Breda virus of calves, the two representatives of a newly proposed family called the Toroviridae. In one sample a toroidal nucleoprotein-like structure was observed within the particles. For two samples a buoyant density of 1.14 g/ml was determined by centrifugation through a sucrose density gradient. One sample possessed a haemagglutinin for rat erythrocytes. The serological relationship between these different viruses was observed by immune electron microscopy, haemagglutination inhibition, and serum neutralisation. The role of these virus-like particles as candidate pathogens of humans is discussed.

Adult↗
PubMed1985

MHC and non-MHC genetic influences on Rous sarcoma metastasis in chickens.

The B5/B5 genotype, in Leghorns, was associated with a high degree of metastasis of Rous sarcoma virus-induced tumors, but in combination with a Leghorn-New Hampshire background markedly less metastasis occurred. Initially, four mating types were used: B5/B5 X B5/B5 chickens from the F5 generation of the cross of Leghorn lines 6(1) and 15(1), B24/B24 X B24/B24 chickens from line UNH 105 (New Hampshires), and reciprocal crosses of B5/B5 X B24/B24 chickens. Subsequently, F2 generation progeny of the cross of B5/B5 and B24/B24 breeders, as well as B24/B24 line UNH 105 and B5/B5 (6(1) X 15(1))F2 chickens, were used. Six-week-old chickens were inoculated in the wingweb with Rous sarcoma virus. Chickens dying during a 10-week period after inoculation were necropsied and suspect metastatic lesions examined histologically. Among 234 terminal chickens from the initial four mating types the incidence of metastasis associated with B5/B5 Leghorns (66%) was substantially higher than for B24/B24 New Hampshires (12%) and B5/B24 progeny of reciprocal Leghorn-New Hampshire crosses (19 and 24%). Subsequently, among 524 terminal hosts in the Leghorn-New Hampshire F2 population, B genotype significantly influenced tumor dissemination. However, among 52 concurrently challenged B5/B5 hosts from the (6(1) X 15(1))F2 population the incidence of metastasis (60%) was significantly higher than among 122 B5/B5 hosts from the Leghorn-New Hampshire F2 population (31%), indicating a non-major histocompatibility complex genetic effect on metastasis.

Animals↗
PubMed1985

Nuclear magnetic resonance study of iron overload in liver tissue.

Whole-tissue and homogenized samples of human liver were studied in a NMR spectrometer, T1 and T2 relaxation times were measured as a function of added inorganic or organic iron. When inorganic iron (Fe+3) was added, pronounced T1 and T2 shortening was noted. However, when organic iron, in the form of ferritin, was added, the amount of T1 and T2 relaxation enhancement was much reduced for the same amount of added iron. The in vitro ferritin results model the situation found in clinical studies of hemochromatosis. Only in cases of severe iron overload were significant decreases in relaxation times observed. The T2 relaxation time was the more reliable indicator of excessive levels of iron in the liver. The large range of T1 and T2 values encountered in normal volunteers precludes the use of MR to quantitatively measure iron levels in the liver. The T1 and T2 relaxation times measured at intervals for one individual tend to fluctuate as well, making the use of MR to follow the course of treatment of iron overload disorders unreliable.

Hemochromatosis↗
PubMed1985

Toxic chemicals in sediments and biota from a creosote-polluted harbor: relationships with hepatic neoplasms and other hepatic lesions in English sole (Parophrys vetulus).

High prevalences of idiopathic hepatic lesions, including neoplasms (e.g., hepatocellular carcinomas, cholangiocellular carcinomas) (27%, 20 of 75 fish) and foci of cellular alteration (putative 'preneoplastic' lesions) (44%, 33 of 75 fish), were found in English sole (Parophrys vetulus) exposed to creosote-contaminated sediments in Eagle Harbor, Puget Sound, WA. Sediments from the contaminated region of the harbor contained particularly high concentrations of aromatic hydrocarbons (e.g., benzo[a]pyrene and benz[a]anthracene), and a variety of nitrogen-containing aromatic compounds (e.g., carbazole and acridine). The composition of the aromatic compounds was characteristic of creosote. Dramatically lower concentrations of aromatic compounds were found in sediments from a reference site in which the bottom-dwelling fish examined were free of detectable neoplastic or 'preneoplastic' hepatic lesions. Food organisms in the stomachs of the English sole from Eagle Harbor contained substantially higher concentrations of aromatic hydrocarbons than comparable organisms from the reference site. The concentrations of individual aromatic hydrocarbons in muscle and liver from the Eagle Harbor fish were low; however, high concentrations of metabolites of aromatic compounds were present in the bile. The findings strongly suggest an association between exposure to creosote and the prevalence of hepatic lesions, including neoplasms, in the bottom-dwelling fish, and furthermore support the putative role of aromatic hydrocarbons in liver carcinogenesis in fish.

Animals↗
PubMed1985

Rhesus diploid rabies vaccine (adsorbed): a new rabies vaccine using FRhL-2 cells.

The FRhL-2 cell line, a diploid line derived from the lung of a fetal rhesus monkey, was used to prepare a potent rabies vaccine by adapting the Kissling strain of rabies virus to FRhL-2 cells, growing the virus in quantity, inactivating the virus with beta-propiolactone, and concentrating the virus by adsorption to aluminum phosphate. High levels of antibody to rabies virus, induced by the vaccine in both guinea pigs and humans at 14 days after immunization, were determined to be IgG. Data from postexposure protocols with guinea pigs and simulated postexposure protocols in humans showed protection and antibody response even when rabies immune globulin was administered at the time of vaccination.

Animals↗
PubMed1985

Toxic chemicals in marine sediment and biota from Mukilteo, Washington: relationships with hepatic neoplasms and other hepatic lesions in English sole (Parophrys vetulus).

High prevalences of idiopathic liver lesions, including 7.5% hepatic neoplasms (e.g., hepatocellular and cholangiocellular carcinomas) and 16.7% foci of cellular alteration (putative preneoplastic hepatic lesions), were found in English sole (Parophrys vetulus) from waters near Mukilteo, a small community on Puget Sound in Washington State. Sediments from the sampling sites contained particularly high concentrations of aromatic hydrocarbons. Substantially lower concentrations of these compounds were found in sediments from another Puget Sound (reference) site in which fish showed no evidence of hepatic neoplasms or foci of cellular alteration. Stomach contents from the fish at Mukilteo contained substantially higher concentrations of the chemicals than did stomach contents of fish from the relatively uncontaminated site. High concentrations of metabolites of aromatic compounds were measured in the bile of fish from Mukilteo. These findings support previously observed relationships between sediment chemicals (e.g., aromatic hydrocarbons) and high prevalences of liver lesions in English sole from Puget Sound. In addition, a dietary route of uptake by English sole of environmental chemicals, including known carcinogens, was documented.

Animals↗
PubMed1984

BK virus specific IgM responses in cord sera, young children and healthy adults detected by RIA.

An IgM capture solid-phase radioimmunoassay (MACRIA) for BK virus (BKV) specific IgM is described. This test was found to be more sensitive in detecting BKV specific IgM than both haemagglutination inhibition and immune electron microscopy with serum fractions from sucrose density gradients. The use of this specific assay allowed large numbers of sera to be examined with ease so that the distribution of BKV specific IgM in different populations could be studied more fully. BKV specific IgM was detected in 11/300 sera from London blood donors, in 24/114 sera from children aged between 2 and 11 years admitted to a paediatric unit and 14/79 sera taken from children aged between 2 and 5 years for the investigation of anti-streptolysin 0 titres. BKV specific IgM was not detected in 404 cord sera examined to investigate the transplacental transmission of BK virus.

Adolescent↗
PubMed1984

Artificial insemination by donor (AID) and the use of surrogate mothers.

Today families are being created by such procedures as test tube fertilization, artificial insemination and surrogate parenting. In addition to traditional couples, moreover, single persons, gay couples and others are seeking to form family units. In the eagerness to produce an offspring there is often little thought given to the needs or the feelings of the child so produced. There is a need for sociomedical data as well as a more open approach in these situations.

Adoption↗
PubMed1983

The FDA report on intraocular lenses.

Clinical studies of intraocular lenses (IOLs) as investigational devices have been regulated in the United States by the Food and Drug Administration (FDA) since February 9, 1978. As of August 1982, data have been collected on more than one million IOLs implanted. During the last 12 months of the study, 409,000 IOLs were implanted. Visual acuity of 20/40 or better at one year after surgery was present in 85% of over 45,000 cases reviewed. Increasing patient age, surgical problems, postoperative complications, and adverse reactions were factors that reduced the visual acuity. The current trend in the USA is for implantation of the posterior chamber and anterior chamber IOLs.

Aged↗
PubMed1982

Complementation of major histocompatibility haplotypes in regression of Rous sarcoma virus-induced tumors in noninbred chickens.

Relative responses to Rous sarcoma virus (RSV)-induced tumors were studied in UNH 105 chickens, a noninbred line of New Hampshires. A total of 799 chickens blood typed for B alloantigens were classified into six genotypes: B23/B23, B24/B24, B26/B26, B23/B24, B23/B26, and B24/B26. Chickens were inoculated with subgroup A Rous sarcoma virus in the left wingweb at 6 weeks of age. The in vivo response was evaluated and given a tumor profile index (TPI) based on the change in tumor size over a 10-week period postinoculation. The TPI's ranged from 1 (regressor) to 3 (progressor). The mean TPI of B23/B26 hosts (1.7) was significantly smaller than that of all other genotypes studied. The mean TPI's of the homozygous genotypes B23/B23, B26/B26, and B24/B24, were 2.0, 2.3, and 2.9, respectively, and differed significantly in all comparisons. These results suggest complementation of haplotypes influencing the anti-Rous sarcoma response.

Animals↗