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Biomedical subjects

C Roberts

Publications and source records attributed to C Roberts.

At least 325 records · Page 18Linked to original sources
PubMed1987

Linkage of the murine steroid sulfatase locus, Sts, to sex reversed, Sxr: a genetic and molecular analysis.

We present genetic and molecular data demonstrating linkage of the gene for steroid sulfatase (Sts) to the mutation sex reversed (Sxr) definitively showing the existance of a functional allele for Sts mapping to the pseudoautosomal region of the mouse Y chromosome. Thus, in mouse, functional Sts genes are present in the pseudoautosomal region of both the X and Y chromosomes. This is in contrast to man where Sts has been mapped to the short arm of the X just centromeric to the pseudoautosomal region. Only a single recombinant separating Sts and Sxr was found out of 103 male meioses analyzed; double recombinants were not found between sex (Tdy), Sts and Sxr. If the rate of recombination in the pseudoautosomal region in male mice is equivalent to that in man and thus 7-10X higher than normal, then our data suggest that the distance between Sts and Sxr (or the telomere of the Y) is approximately 100-200 kb in length. Our data is in contrast to a recent report of a recombination frequency separating Sts and Sxr of as high as 6.2-9.8%.

Animals↗
PubMed1987

Success of re-use of cardiac electrode catheters.

The feasibility of cardiac electrode catheter re-use was prospectively evaluated over a 5-year period (1981 to 1986), during which time 178 catheters were used 1,526 times for 847 electrophysiologic procedures. Detailed records of catheter testing and use were maintained. No complications were encountered during the study period. All re-used catheters functioned for cardiac pacing and electrographic recording. Surveillance cultures and biologic indicators revealed that adequate sterilization procedures were used. Thus, electrode catheters may be safely re-used provided a thorough cleaning, testing and record-keeping system is instituted. This may result in lower patient cost (approximately $30 per re-use vs [200 per single use) for electrophysiologic catheterization.

Cardiac Catheterization↗
PubMed1987

Human immunodeficiency virus infection in two cohorts of homosexual men: neutralising sera and association of anti-gag antibody with prognosis.

Sequential sera from 48 subjects infected with human immunodeficiency virus type I (HIV-I) were examined over 36 months for the presence of neutralising antibodies, and for specific anti-gag (p24) and anti-env (gp41) antibodies to HIV-I. Results were interpreted in terms of clinical outcome during the period 1982/3 to 1985/6. HIV-I-infected subjects who remained symptom-free, by comparison with those who manifested AIDS or AIDS-related complex (ARC), had a significantly higher titre of anti-p24 antibodies throughout the 3 years, as measured by competitive enzyme-linked immunosorbent assay and radioimmunoprecipitation. The symptomless subjects also showed a trend towards an increasing neutralising antibody titre with time. There was no relation between anti-gp41 titre and clinical outcome, nor an independent relation between anti-p24 and neutralising titre. A lower or falling titre of anti-p24 antibody was associated significantly with clinical progression, up to 27 months before development of AIDS/ARC.

AIDS-Related Complex↗
PubMed1987

The effects of low doses of caffeine on human performance and mood.

Caffeine is thought to have stimulant-like behavioral effects on mood and performance. However few behavioral studies have examined this substance's acute effects when administered in a range of doses that include the low doses typically found in foods and over-the-counter drugs. We therefore gave single doses of caffeine (32, 64, 128 and 256 mg) to 20 healthy male subjects and assessed various aspects of performance and self-reported mood states, as well as plasma caffeine concentration. As little as 32 mg (which elevated plasma caffeine concentration to less than 1 microgram/ml), typical of the dose found in a single serving of a cola beverage, and less than that found in a single cup of coffee or a single dose of over-the-counter drugs, significantly improved auditory vigilance and visual reaction time. All other caffeine doses administered also significantly improved performance on these tests. No adverse behavioral effects, such as increased anxiety or impaired motor performance, were noted even at the highest dose administered.

Adolescent↗
PubMed1987

Ribosomal RNA gene amplification: a selective advantage in tissue culture.

A CCRF-CEM (human T-cell leukemia) line, initially made resistant to methotrexate by a four-step increase in drug concentration, revealed a large marker of one chromosome #14 in all cells after a 6-month period of culture in the absence of drug. The marker is the result of a triple duplication of both the satellite and stalk. In situ hybridization with 3H-cRNA and NOR banding proved that ribosomal DNA had been amplified and was actively transcribed. Flow cytometric analysis showed a significant increase of RNA versus DNA in G1 cells compared with those of the original drug-resistant parent. The abnormal chromosome appeared after the removal of methotrexate from culture and may be related to the faster doubling time of this line compared with the parent line.

Chromosome Banding↗
PubMed1987

Cytogenetic findings in cell lines derived from four ovarian carcinomas.

Six cell lines, established from four primary ovarian carcinomas were examined cytogenetically. The lines varied greatly in their chromosome complement. All cells from the lines were aneuploid, although one cell line contained two populations having a pseudodiploid and a pseudotetraploid modal chromosome number. Every chromosome group was involved with loss and gain of chromosomes, but some individual chromosomes were more prone to aneuploidy than others. Chromosome #6 was the most stable throughout. Structural changes gave rise to many marker chromosomes. Although most markers were random and the majority unidentifiable, some abnormalities of clonal origin were found. Deletions especially of chromosome #1, were the most common change. Further sequential studies may elicit the origin, stability, and timing of the chromosome abnormalities.

Adenocarcinoma↗
PubMed1987

An outbreak of Salmonella typhimurium gastroenteritis in a psychiatric hospital.

An outbreak of Salmonella typhimurium (phage type 12) infection involving 11 patients and 12 members of staff occurred in a psychiatric hospital in Merseyside during a 3-week period in September and October 1984. Bacteraemia did not occur in any patients, those affected having a mild self-limiting diarrhoea. The source of the organism remained unknown but the most probable means of transmission was by person to person contact. The outbreak was controlled by transferring affected patients to an isolation ward. Staff were encouraged to report gastrointestinal symptoms and remain off work until symptom free or until the results of cultures were known. The problems of managing the outbreak are discussed.

Cross Infection↗
PubMed1987

Salmonella screening of pregnant women.

Over a 9-year period all maternity patients were screened by rectal swab for salmonella excretion at the time of delivery. 30,471 mothers were screened and 60 (0.2%) yielded salmonellas, 43 (72%) of whom were symptomless excretors. Seven of the 60 babies (12%) excreted salmonellas, all of which were the same organism as in the mothers. Five had uncomplicated gastroenteritis in the neonatal period, but no mother or child suffered invasive disease and no incidents of hospital cross-infection occurred. These results show that screening is unjustified unless there are problems of cross-infection.

Cross Infection↗
PubMed1987

Expression of human papillomavirus type 6 and type 16 capsid proteins in bacteria and their antigenic characterization.

The L1 and L2 capsid proteins encoded by human papillomavirus types 6 and 16 (HPV-6 and HPV-16) have been synthesized in bacteria. Antisera were raised against the HPV-6 L1- and L2-beta-galactosidase fusion proteins and against an HPV-16 L1 C-terminal peptide which was 14 amino acids long. The HPV-16 L1 peptide antibodies have been shown to be highly reactive with the HPV-16 L1-beta-galactosidase protein but not against the equivalent HPV-6 L1-beta-galactosidase fusion protein. The effectiveness of these antibodies was compared with commercially available antibovine papillomavirus type 1 (BPV-1) antibodies and the results demonstrated that the anti-BPV-1 antibodies reacted well against HPV-6 L1-beta-galactosidase but not against HPV-16 L1-beta-galactosidase. In addition, the L2 portion of the HPV-6 L2-beta-galactosidase fusion protein appeared particularly immunogenic, since antibodies raised against this fusion protein were predominantly reactive with the L2 moiety. The HPV-16 L1 peptide antibodies described here will be preferred reagents for the specific detection of HPV-16 capsid antigens, which may be particularly important in early diagnosis of HPV-16 infection.

Antibodies, Viral↗
PubMed1987

Adenoid infection: its relationship to otitis media, glue ear and tonsillitis.

In a prospective study, 69 children admitted for adenoidectomy were divided into 4 subgroups according to their symptomatology. These were: nasal obstruction alone; glue ear; recurrent ear aches and probable otitis media; and recurrent sore throats and probable tonsillitis. The adenoids removed were bacteriologically analysed to assess both the spectrum of organisms present and the colony counts per gram of adenoid tissue (10(5) organisms per gram was regarded as representing infection). There was no significant difference between the subgroups with regard to either the presence of infection or the spectrum of organisms grown. We conclude that while infection in the adenoid bed must be involved in the pathogenesis of bacterial otitis media, the concentration of organisms present in the adenoids is unimportant and other factors must be responsible for the migration of organisms up the Eustachian tube.

Adenoids↗
PubMed1987

Purple urine bag syndrome.

Purple pigment extracted from the urinary catheters and collecting bags of two elderly female patients was analysed by a variety of chemical techniques, including mass spectroscopy and nuclear magnetic resonance. Although previous studies identified the pigment as indigo, we failed to confirm this. Our analysis also demonstrated that indicanuria is not a requirement for the production of the pigment and furthermore indicates that the molecular structure of the pigment is either a steroidal or bile acid conjugate.

Aged↗