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Biomedical subjects

M Collins

Publications and source records attributed to M Collins.

At least 271 records · Page 15Linked to original sources
PubMed1987

Immobilization of DNA via oligonucleotides containing an aldehyde or carboxylic acid group at the 5' terminus.

A general method for the immobilization of DNA through its 5'-end has been developed. A synthetic oligonucleotide, modified at its 5'-end with an aldehyde or carboxylic acid, was attached to latex microspheres containing hydrazide residues. Using T4 polynucleotide ligase and an oligonucleotide splint, a single stranded 98mer was efficiently joined to the immobilized synthetic fragment. After impregnation of the latex microspheres with the fluorescent dye, Nile Red and attachment of an aldehyde 16mer, 5 X 10(5) bead-DNA conjugates could be detected with a conventional fluorimeter.

Aldehydes↗
PubMed1987

Hydrolethalus (Salonen-Herva-Norio) syndrome: further clinicopathological delineation.

Two brothers with severe CNS abnormalities, cleft lip/palate, polydactyly, and lung hypoplasia are reported as examples of the hydrolethalus syndrome, an autosomal recessive disorder. Death from cardiopulmonary arrest occurred in patient 1 at age 4 months and in patient 2 at age 17 days. Detailed radiological and neuropathological description is provided on patient 2. We recommend realtime ultrasonography and, when indicated, fetoscopy for antenatal detection of the craniofacial and limb malformations associated with this syndrome.

Abnormalities, Multiple↗
PubMed1987

Desmin: its value as a marker of muscle derived tumours using a commercial antibody.

This study examined the staining reactions of a commercially available anti desmin antibody in 192 soft tissue sarcomas, 30 carcinomas and 22 malignant melanomas. Only 63% of rhabdomyosarcomas and 50% of leiomyosarcomas showed a positive reaction. Three non muscle sarcomas also reacted with the antibody. No positivity was seen amongst the carcinomas or the melanomas. These results do not compare favourably with the documented results of non commercial desmin antibodies in the literature. The most likely cause of the discrepancy in the varying results is the differing source of the antibody.

Adolescent↗
PubMed1987

ELISA assays for IgM and IgG rheumatoid factors: their clinical correlations during therapy with slow-acting anti-rheumatic drugs.

A longitudinal study of changes in rheumatoid factor levels and their correlations with other clinical and laboratory assessment of disease activity followed 45 rheumatoid arthritis patients during 12 months continuous therapy with gold and penicillamine. Rheumatoid factors were measured by the titred latex assay and by ELISA assays for IgM and IgG rheumatoid factor. The IgM ELISA assay correlated strongly with the titred latex assay and weakly with the IgG rheumatoid factor assay at 0, 6 and 12 months. All showed significant falls with treatment, and ELISA assays were not more sensitive indicators than the latex assay. Correlations of initial rheumatoid factor levels by all 3 assays to 34 other clinical and laboratory assessments showed that only a small number of weak correlations existed; there were more at 6 and 12 months, but still not many. Changes in rheumatoid factor levels over 0-6 months showed no significant correlation to changes in other variables. There were no more correlations with ELISA assays than with titred latex rheumatoid factor. We conclude that ELISA rheumatoid factor assays have no clinically relevant advantage over the titred latex assay when following rheumatoid patients treated with gold or penicillamine.

Arthritis, Rheumatoid↗
PubMed1987

Detection of human DNA polymorphisms with a simplified denaturing gradient gel electrophoresis technique.

Single base pair differences between otherwise identical DNA molecules can result in altered melting behavior detectable by denaturing gradient gel electrophoresis. We have developed a simplified procedure for using denaturing gradient gel electrophoresis to detect base pair changes in genomic DNA. Genomic DNA is digested with restriction enzymes and hybridized in solution to labeled single-stranded probe DNA. The excess probe is then hybridized to complementary phage M13 template DNA, and the reaction mixture is electrophoresed on a denaturing gradient gel. Only the genomic DNA probe hybrids migrate into the gel. Differences in hybrid mobility on the gel indicate base pair changes in the genomic DNA. We have used this technique to identify two polymorphic sites within a 1.2-kilobase region of human chromosome 20. This approach should greatly facilitate the identification of DNA polymorphisms useful for gene linkage studies and the diagnosis of genetic diseases.

Chromosomes, Human, Pair 20↗
PubMed1987

Protein kinase C activation enhances cAMP accumulation in Swiss 3T3 cells: inhibition by pertussis toxin.

Addition of phorbol 12,13-dibutyrate (PBt2) in the presence of forskolin or cholera toxin caused marked (6- to 8-fold) and rapid accumulation of cAMP in Swiss 3T3 cells. The effect of PBt2 is mediated by protein kinase C because the synthetic diacylglycerol 1-oleoyl-2 acetylglycerol substitutes for PBt2 in enhancing cAMP accumulation and because the enhancing effect of either PBt2 or 1-oleoyl-2-acetylglycerol was prevented by down-regulation of protein kinase C. Vasopressin, which activates protein kinase C but does not directly affect adenylate cyclase in 3T3 cells, also enhanced cAMP accumulation in cells treated with cholera toxin or forskolin. This effect was abolished by down-regulation of protein kinase C. Treatment with pertussis toxin blocked the enhancing effect of PBt2 in a concentration- and time-dependent manner. Pertussis toxin neither prevented protein kinase C activation by PBt2 nor other biologic responses elicited by PBt2. The results presented here suggest an unusual function for a pertussis toxin substrate--namely, coupling protein kinase C activation to cAMP production.

Adenylate Cyclase Toxin↗
PubMed1987

Anti-alpha 1-antichymotrypsin staining of 194 sarcomas, 38 carcinomas, and 17 malignant melanomas. Its lack of specificity as a tumour marker.

A polyclonal commercially available antiserum to alpha 1-antichymotrypsin (alpha 1ACT) was reacted with 194 sarcomas, 38 carcinomas, and 17 malignant melanomas; 61 of 194 sarcomas, 14 of 38 carcinomas, and 10 of 17 malignant melanomas reacted positively. Thirteen categories of sarcomas were examined. All but one group (haemangiopericytomas) showed positively staining tumour cells. Malignant fibrous histiocytomas, angiosarcomas, and Kaposi's sarcomas showed positive staining in over 70% of tumours. All categories of carcinomas examined, with the exception of transitional cell carcinomas, stained positively. The results of this study suggest that the use of alpha 1ACT antiserum is of little value in the differential diagnosis of either sarcomas or carcinomas, nor can it be used as a specific histiocytic marker.

Antibodies↗
PubMed1987

Blinking patterns in soft contact lens wearers can be altered with training.

The blinking patterns of 15 soft contact lens wearers were recorded with a concealed video camera. Each of 20 consecutive blinks were graded, during slow motion replay of the video, as either complete, incomplete, forced, or twitch. Ten of these subjects were instructed to perform blinking exercises for a period of 2 weeks and the remaining 5 subjects acted as controls. After these exercises all the experimental group displayed an increased frequency of complete blinks, whereas the blinking patterns of the control group remained unchanged. Blinking exercises are likely to alleviate many of the signs and symptoms associated with incomplete blinking amongst contact lens wearers.

Blinking↗
PubMed1987

Reduction of anthralin inflammation by potassium hydroxide and Teepol.

Application of 1% potassium hydroxide (KOH) reduced subsequent development of anthralin inflammation without loss of its therapeutic effect on psoriasis. Teepol had a similar but smaller effect on subsequent development of inflammation. The action of KOH appears to have resulted from enhanced oxidation of anthralin to inactive products and the action of Teepol to have increased anthralin solubility and removal. The effect of KOH and Teepol decreased with time after anthralin application and both were ineffective by 24 h, indicating that anthralin persists on the skin in an active form for up to 24 h after a single application. The reduction of anthralin inflammation without loss of therapeutic effect is potentially useful in short contact anthralin therapy.

Adolescent↗
PubMed1987

Vimentin: an evaluation of its role as a tumour marker.

In this study we examined 198 sarcomas, 38 carcinomas, 13 'tumours with a spindle cell component' and 22 malignant melanomas with a commercial monoclonal vimentin antibody. All histopathological material was formalin fixed and paraffin embedded. The results show this antibody to be a sensitive and specific marker of mesenchymal derivation or differentiation. It is a useful tool in separating sarcomas from most carcinomas, and in separating malignant melanomas from carcinomas. When used in combination with a cytokeratin antibody it identifies carcinosarcomas and synovial sarcomas.

Antibodies, Monoclonal↗
PubMed1987

Sexual activity, contraceptive use, and other risk factors for symptomatic and asymptomatic bacteriuria. A case-control study.

In a study to determine the risk factors for urinary tract infection in college-aged women, women who presented with acute urinary tract infection to the student health service were compared to women without bacteriuria who presented with complaints of other acute illnesses. Among women who were sexually active, the following multivariate adjusted odds ratios (95% confidence intervals) were found; intercourse in the previous 48 hours, 58.1 (11.9 to 284.1); intercourse only in the previous 3 to 7 days, 9.1 (1.9 to 44.1); diaphragm use in the previous 48 hours, 8.4 (3.4 to 21.1); urination after intercourse, 0.5 (0.3 to 0.9); and past history of urinary tract infection, 2.7 (1.5 to 5.0). Several other factors previously postulated to be related to urinary tract infection were found not to be associated, including oral contraceptive use, tampon use, and direction of wiping after a bowel movement. When the women with symptomatic bacteriuria were compared to women with asymptomatic bacteriuria, the results were similar, except diaphragm use and urination after intercourse were no longer associated with urinary tract infection. When the women with asymptomatic bacteriuria were compared to women without symptoms and without bacteriuria, diaphragm use remained the only statistically significant risk factor. These findings should be taken into account in attempts to prevent urinary tract infection, as well as in subsequent studies of this disease.

Adult↗
PubMed1986

Lipid peroxidation in regenerating rat liver.

Rats entrained to a strictly regulated lighting and feeding schedule have been subjected to partial hepatectomy or a sham operation. In the partially hepatectomised animals the period of liver regeneration is characterised by regular bursts of thymidine kinase activity. Liver microsomes from rats, at times corresponding to maximum thymidine kinase activity, have much reduced rates of lipid peroxidation compared to control preparations: this is due in part to increased levels of lipid-soluble antioxidant at times of maximal DNA synthesis. This temporal relationship between thymidine kinase and lipid peroxidation is consistent with the view that lipid peroxidation is decreased prior to cell division.

Animals↗
PubMed1986

Studies on lipid peroxidation in normal and tumour tissues. The Novikoff rat liver tumour.

A study has been made of the factors that contribute to the decreased rates of lipid peroxidation under different pro-oxidant conditions in intact Novikoff tumour cells, and in microsomal suspensions prepared from Novikoff tumour cells, compared with isolated normal rat hepatocytes and microsomal suspensions prepared from normal rat liver. The pro-oxidant conditions were the addition of either NADPH, NADPH + ADP + iron, NADPH + CCl4 or ascorbate+iron to the experimental systems used, or exposure to gamma-radiation. Contributory factors to the lower rates of lipid peroxidation observed include: a significant decrease in the polyunsaturated fatty acid content of Novikoff cells or Novikoff microsomes; the decreases are especially marked for the C20:4 and C22:6 fatty acids; a very marked reduction in NADPH-cytochrome c reductase; and no detectable content of cytochrome P-450. Another, and in our opinion critical, contribution to the diminished rate of lipid peroxidation in the tumour material is the substantial increase in alpha-tocopherol relative both to total lipid and to methylene-interrupted double bonds in fatty acids. Moreover, the alpha-tocopherol is the major contributor to lipid-soluble chain-breaking antioxidant in lipid extracts of normal liver and of Novikoff tumour material.

Animals↗
PubMed1986

Effects of stable dust on farm animals--a review.

The relationship between air quality--its dust content--and respiratory diseases of animals in the food industry and otherwise is examined. The correlation between dust content and incidence of disease in farm animals is also discussed. Lesions caused either directly or indirectly by dust-transported microorganisms are reviewed. Effects of dust on animal performance are included. This review is an attempt to compile available information on the natural occurrence of stable dust and the possibilities for its measurement and control.

Air Pollutants↗