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Biomedical subjects

M Collins

Publications and source records attributed to M Collins.

At least 253 records · Page 14Linked to original sources
PubMed1989

The onset of prolonged glare recovery with age.

The effects of ageing upon the recovery of contrast discrimination following exposure to a bright source of light (glare recovery) were investigated. A total of 65 subjects were tested, with a distribution of ages ranging from 16 to 79 years. Total glare recovery times were relatively constant up to about 56 years of age, after which they became significantly prolonged. Contrast thresholds to a small spot target gradually increased with age.

Adaptation, Ocular↗
PubMed1989

Effect of a dentifrice containing triclosan and a copolymer on plaque formation: a 6-week clinical study.

A 6-week, double-blind, clinical study was conducted to determine the effect on plaque formation of a dentifrice containing 0.3% triclosan and 2% of a copolymer of methoxyethylene and maleic acid as compared to a placebo dentifrice. Ninety-one male and female adult subjects with baseline Quigley-Hein Plaque Index scores of 1.5 or greater were entered into the study. Eighty-six subjects completed the entire 6 weeks of the study. Subjects were initially stratified into two balanced groups using their baseline Plaque Index score and each group was then randomly assigned to the use of one of the two test dentifrices. All subjects received an oral prophylaxis at the start of the study. Subjects were given either the triclosan/copolymer dentifrice or the placebo dentifrice and a soft-bristled toothbrush for home use and were instructed to brush their teeth twice daily (morning and evening) for 1 minute at each toothbrushing. At the end of the 2, 4 and 6 weeks' use of their assigned dentifrice, the subjects had their teeth evaluated for plaque formation. The results indicated that the group assigned to the triclosan/copolymer dentifrice had 11.89%, 11.83% and 20.01% less plaque formation after 2, 4 and 6 weeks' use of the dentifrices, respectively, than the group assigned to the placebo dentifrice. All reductions in plaque formation were statistically significant at the 97% level of confidence or greater. The effect was more pronounced on the tooth surfaces that had the heaviest plaque formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Male sexual dysfunction.

Impotence and premature ejaculation are common male sexual dysfunctions that are present in most adult primary care populations. New information about the vascular and neurophysiologic mechanisms of impotence have been joined by new technology to advance the medical practices in the diagnosing and treating of the impotent male. While similar advances have not occurred in the understanding of premature ejaculation, behavior therapy techniques are extremely effective with motivated couples. Primary care physicians can aid male patients with sexual dysfunction by attempting to identify them, initiating diagnostic and treatment programs, and referring patients for additional evaluations or specialized procedures when indicated.

Ejaculation↗
PubMed1988

Measurement of natural killer cell cytotoxicity by area under a cytotoxic curve. A method suitable for rheumatoid arthritis.

Calculation of the area under a curve derived from a 51Cr cellular release assay gives a reproducible expression of cellular cytotoxicity and correlates well with results at fixed lymphocyte-to-target cell ratios and with lytic units at 20% and 30% cytotoxicity. This method is suitable for quantifying the low cytotoxicity seen in rheumatoid arthritis. The area under the cellular cytotoxic curve may be calculated using a simple mathematical formula or by computer analysis.

Arthritis, Rheumatoid↗
PubMed1988

A novel diagnostic method based on DNA strand displacement.

A novel approach for the detection of specific DNA or RNA sequences based on branch migration and DNA strand displacement is described. A partially double-stranded probe complex is prepared with a detectable label on one of the two strands and incubated with analyte molecules under hybridization conditions. The analyte molecules hybridize to the single-stranded portion of the probe complex and undergo branch migration to release the labelled DNA strand from the complex. Initial characterization of the assay indicates that both qualitative and quantitative information about analytes present in a sample can be obtained. The strand displacement assay is more sensitive to sequence alterations in the analyte than is a hybridization assay and can be promoted by rec A protein at 37 degrees C. Finally, a method for preparing probe complexes by cloning in a single-stranded DNA vector is also described.

DNA↗
PubMed1988

Right pneumonectomy syndrome: a lethal complication of lung resection in a newborn with cystic adenomatoid malformation.

A newborn girl underwent a right pneumonectomy for cystic adenomatoid malformation. She subsequently developed compression of the trachea and left mainstem bronchus by a combination of aortic arch, pulmonary artery, and ductus arteriosus. She died while planning aortic suspension, and the anatomic relationships were confirmed by autopsy. This problem is potentially treatable by a variety of means.

Coronary Angiography↗
PubMed1988

Effect of UVB therapy and a coal tar bath on short contact dithranol treatment for psoriasis.

The effect of UVB therapy after short contact dithranol therapy (SCDT) was examined in 53 patients with psoriasis. After dithranol application, patients were randomly allocated to receive either a tar bath and UVB therapy (27 patients) or an emulsifying ointment bath only (26 patients). Forty eight patients completed the study; 16 of the 21 dithranol only patients cleared in a mean of 19.5 days compared with 20 of the 27 dithranol + UVB patients who cleared in a mean of 20.3 days. These differences were not significant. Similarly there was no significant difference in response between the dithranol only and dithranol UVB group as measured by the change in plaque thickness measured using Harpenden calipers, and the severity of psoriasis assessed by the extent of the rash, the degree of scaling, redness and induration. Thirteen of the 16 dithranol only patients who cleared relapsed in a mean of 10.6 weeks compared with 14 of the 20 dithranol UVB patients who relapsed after a mean of 18.9 weeks (P less than 0.05). Comparison of pre- and post-treatment full blood count, biochemical screen and urinalysis showed no evidence of systemic toxicity due to SCDT. This study shows that UVB therapy does not improve the clearance of psoriasis in SCDT, but does significantly postpone relapse.

Adolescent↗
PubMed1988

The use of antipyrine clearance to measure liver damage in psoriatic patients receiving methotrexate.

Salivary antipyrine clearance was measured in 15 patients with psoriasis receiving methotrexate and related to liver biopsy changes and routine liver function tests, to determine whether antipyrine clearance could be used as a non-invasive method for monitoring liver function. Comparison of the salivary antipyrine clearance in the methotrexate group (mean 0.51 ml/min/kg, range 0.26-0.81) with 15 matched psoriatic controls (mean 0.54 ml/min/kg, range 0.34-0.99) showed no significant difference. Liver biopsy changes were scored for fatty change, fibrosis, liver cell necrosis and portal tract infiltrate. Total liver biopsy scores correlated significantly with antipyrine clearance/kg body weight (r = -0.72, P less than 0.05). There was no significant correlation of total liver biopsy scores with the other liver function tests. Correlation of the individual liver biopsy changes and antipyrine clearance showed a significant correlation with fatty change (r = -0.75, P less than 0.01), but not with fibrosis (r = -0.53), liver cell necrosis (r = -0.54) or infiltrate (r = -0.41).

Adult↗
PubMed1988

Contact dermatitis in patients with leg ulcers. The prevalence of late positive reactions and evidence against systemic ampliative allergy.

100 patients with leg ulcers were patch tested against a standard battery of allergens. The readings were carried out daily from the 2nd to the 7th days. 55 patients showed positive reactions to one or more allergens. 32% of positive reactions developed for the first time after 48 h and 11% after 72 h. No single day or combination of two days gave 100% positive results. A single reading on the 4th day gave the highest number of positive reactions at 92%. The prevalence of positive patch tests was significantly higher in patients with surrounding eczema, and in patients with positive patch tests the ulcer duration was significantly longer than in those with negative patch tests. The total number of positive results in individuals increased linearly with the duration of the ulcer. Of allergens to which the ulcer was exposed, the occurrence of multiple sensitivity was significantly greater than predicted from the prevalence of individual sensitivities. However, there was no association between medicaments and metal sensitivity. This, together with the absence of an exponential rise in the number of allergens with the duration of ulcer, does not support the theory of systemic ampliative allergy.

Aged↗
PubMed1988

Incidence of acute otitis media in infants in a general practice.

A 12-month study of the incidence of acute otitis media in children under three years of age in an urban practice of 10 000 patients showed that acute otitis media accounted for one in 10 of all episodes of illness presented. In contrast to findings in Scandinavia and the USA the incidence of acute otitis media in the first year of life (11.5%) was lower than in the second year (28.6%). The study included a number of children in their third year and the incidence in this group was higher still (30.8%).The problems of defining acceptable diagnostic criteria for acute otitis media, and the relation of these diagnostic criteria to the differences in our results compared with previous studies are discussed.

Acute Disease↗
PubMed1987

Alterations in DNA helix stability due to base modifications can be evaluated using denaturing gradient gel electrophoresis.

DNA molecules that differ by a single base-pair can be separated by denaturing gradient gel electrophoresis due to the sequence-specific melting properties of DNA. Base modifications such as methylation are also known to affect the melting temperature of DNA. We examined the final position of DNA fragments containing either 5-methyl-cytosine or 6-methyl-adenine in denaturing gradient gels. The presence of a single methylated base within an early melting domain resulted in a well-resolved shift in fragment position relative to the unmethylated sequence. In addition, fragments containing hemimethylated and fully methylated sites could be distinguished, and a proportionally larger shift was observed with an increasing number of methylated bases. Denaturing gradient gel electrophoresis thus provides a sensitive method for analyzing the methylation state of DNA, which is not dependent on the presence of restriction enzyme cleavage sites. We also demonstrate that denaturing gradient gel electrophoresis can be used to obtain a quantitative estimate of the change in helix stability caused by modification of one or two bases in a complex DNA sequence. Such estimates should allow more accurate modeling of melting of natural DNA sequences.

Adenine↗
PubMed1987

Synovial sarcomas. True carcinosarcomas?

The histogenesis of synovial sarcomas remains controversial. An origin from epithelium, synovium, or synovial-related cells and neural tissue has been advanced. Using a combination of a cytokeratin (epithelial marker) antibody and a vimentin (mesenchymal marker) antibody, this study suggests that a synovial sarcoma might be regarded as a carcinosarcoma. It also highlights the diagnostic utility of those antibodies in the diagnosis of synovial sarcomas.

Carcinosarcoma↗