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Biomedical subjects

M Collins

Publications and source records attributed to M Collins.

At least 289 records · Page 16Linked to original sources
PubMed1986

Defective natural killing activity but retention of lymphocyte-mediated antibody-dependent cellular cytotoxicity in patients with the X-linked lymphoproliferative syndrome.

Cellular mediated immune responses in vitro of six males with X-linked lymphoproliferative syndrome (XLP) were investigated. Impaired natural killing (NK) activity compared to seven controls (P less than 0.001) and interferon-alpha activation (P less than 0.011) were detected. However, normal numbers of lymphocytes expressing NK-associated antigens (Leu-7 and MO1) and large granular lymphocytes (LGL) were observed in all patients. Normal lymphocyte-mediated antibody-dependent cellular cytotoxicity (ADCC) (P less than 0.531) was found. NK and ADCC activities have been regarded as being mediated by the same subsets of lymphocytes, however, results of this study do not support this hypothesis: lymphocytes with impaired NK but normal ADCC functions (NK-/K+) were found in males with XLP.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1986

The effects of memory elaboration on adult age differences in incidental recall.

To test the hypothesis that elaboration of information declines with advancing age, young and elderly adults were tested for incidental recall of target words in base sentences, sentences for which precise (relevant) or imprecise (irrelevant) elaborations were provided, or sentences for which precise or imprecise elaborations were participant-generated. Age differences were greater when participants were instructed to generate precise elaborations than when they were provided precise elaborations, and elderly adults generated fewer precise elaborations than young adults. Results were discussed as reflecting the pervasiveness of elderly adults' difficulty in constructing effective elaborations.

Adult↗
PubMed1986

Staining for factor VIII related antigen and Ulex europaeus agglutinin I (UEA-I) in 230 tumours. An assessment of their specificity for angiosarcoma and Kaposi's sarcoma.

In this study we examined the staining reactivity of commercially available antisera to factor VIII related antigen (F VIII RAg) and Ulex europaeus agglutinin I (UEA-I) on sections from 230 formalin fixed paraffin embedded tumours. These included 196 sarcomas, 20 carcinomas and 14 angiomas. All angiomas showed positive staining for F VIII RAg; all carcinomas showed negative staining; the vasoformative areas of all angiosarcomas stained positively but only four of six angiosarcomas showed positive staining of their solid areas; of seven Kaposi's sarcomas, all showed positive staining of vessels and six showed positive staining of the spindle cell component. In the remaining 181 non-vascular sarcomas there was a false positive result in four tumours (2.2%), three of which had a history of irradiation. Pre-radiotherapy biopsies of these three tumours stained negatively with anti-F VIII RAg. UEA-I was demonstrated in all the angiomas studied, in all angiosarcomas (including the solid components) and in well-formed vessels of all Kaposi's sarcomas, but only in the spindle cell component of 3/6. However, there was an unacceptably high rate of false positive staining amongst the carcinomas and non-vascular sarcomas. In conclusion, F VIII RAg is a specific but not a sensitive marker of angiosarcomas; UEA-I is a sensitive but not a specific marker of angiosarcomas.

Adolescent↗
PubMed1986

Prediction of progressive joint damage in patients with rheumatoid arthritis receiving gold or D-penicillamine therapy.

Seventy two patients with classical or definite rheumatoid arthritis (RA) were randomly allocated to receive gold or D-penicillamine therapy (DPA) in a prospective study designed to evaluate whether it is possible to predict which patients will show radiological progression despite therapy. Forty five patients completed 12 months' treatment. There were no significant demographic or clinical differences between them and the 27 drop outs. Twenty of the 45 patients showed no radiological progression between six and 12 months. These patients had less severe initial radiological damage, lower levels of serum aspartate transaminase (serum AST) and lactic dehydrogenase (LDH), but higher levels of serum cholesterol. Twenty five patients did show progression during the six to 12 month period. This group included all the men with nodules. Of the 43 pretreatment clinical and laboratory variables examined, however, the majority failed to predict whether or not progression would subsequently occur. This included the acute phase response and seropositivity.

Arthritis, Rheumatoid↗
PubMed1986

Antineuron specific enolase staining reactions in sarcomas and carcinomas: its lack of neuroendocrine specificity.

A commercially available polyclonal antiserum (Dakopatts) raised against bovine neuron specific enolase (NSE) was reacted with 197 sarcomas, 32 carcinomas, 11 carcinoid tumours and 20 malignant melanomas to assess its specificity for neuroendocrine tumours. All the tumours had been fixed in formalin and embedded in paraffin. Positive tumour cells were found in two of 11 squamous cell carcinomas, one of 11 adenocarcinomas, 10 of 10 oat cell carcinomas, 11 of 11 carcinoid tumours, 16 of 20 malignant melanomas, four of seven clear cell sarcomas, nine of 25 leiomyosarcomas, four of 22 rhabdomyosarcomas, one of seven angiosarcomas and one of 20 synovial sarcomas.

Antibody Specificity↗
PubMed1986

The importance of disease prevalence in transporting clinical prediction rules. The case of streptococcal pharyngitis.

Because clinical prediction rules often are applied in new settings to calculate the probability of a disease, we evaluated the accuracy of three rules for predicting streptococcal pharyngitis in 310 patients. Use of the rules led to overestimations of disease probability in 47%, 82%, and 93% of the patients. When we used receiver-operating characteristic curve analysis, no rule lost power to discriminate streptococcal from nonstreptococcal causes of pharyngitis. The overestimations in disease probability likely were caused by differences in disease prevalence between our setting (5%) and the settings in which they were developed (15% to 17%). All rules led to accurate predictions when they were adjusted for the disease prevalence found in our setting using a likelihood ratio formulation of Bayes' theorem. The value of prediction rules, like that of other diagnostic tests, is affected by differences in disease prevalence in different settings. Failure to recognize and adjust for these differences may cause poor decision making or the premature dismissal of valid rules.

Humans↗
PubMed1986

Strand displacement applied to assays with nucleic acid probes.

This novel method for the detection of specific nucleic acid sequences has potential applications to clinical diagnosis. During hybridization, a signal-bearing nucleic acid strand is displaced by the target nucleic acid from a partially single-stranded complementary probe strand of nucleic acid. The probe:signal strand complex is prepared by hybridizing single-stranded probe that is entirely complementary to the target nucleic acid with a shorter signal sequence that is complementary to a portion of the probe strand. The sample nucleic acid is added to this hybrid complex under hybridization conditions. The target sequence, if present in the sample, will hybridize first to the unoccupied probe sequences, and then will displace the labeled strand by branch migration. By this "strand displacement" the signal strands are freed in solution, where they may be separated from those still hybridized; the quantity of label measured is directly proportional to the amount of analyte sequences in the sample. This method, demonstrated here for model and synthetic DNAs, can easily be adapted for the detection of any RNA or DNA sequence and obviates the need for immobilization of sample. A wide variety of labeling techniques can be used, and the displacement can be performed in solution or with the hybrid complex attached to a solid support. This assay circumvents nonspecific binding of label to the filter matrix and the laborious washing steps inherent in other assays involving nucleic acid probes.

Animals↗
PubMed1985

The accuracy of experienced physicians' probability estimates for patients with sore throats. Implications for decision making.

Ten physicians recorded their treatment decisions and estimated probabilities of streptococcal infection for patients with sore throats. Of 308 throat cultures, 15 (4.9%) were positive for group A streptococci. The physicians overestimated the probability of a positive culture for 81% of their patients and their estimates and treatment decisions were strongly associated. Of 104 patients treated before culture results were available, only eight had positive cultures. Probability overestimation may have been due to neglect of the low culture-positive rate, assignment of undue importance to weakly predictive or highly intercorrelated clinical features, and a value-induced bias, occurring when features important for treatment are erroneously linked to the likelihood of disease. Cognitive limitations in information processing may limit the effectiveness of pharyngitis management protocols that require subjective estimates of disease probability.

Adolescent↗
PubMed1985

Use of refined perinatal mortality rate trends to evaluate the effect of a confidential inquiry.

Standardised perinatal mortality rates and cause-specific rates were used to evaluate the effect of a confidential inquiry into perinatal deaths in West Glamorgan obstetric units. Cause of death was classified by means of 5 pathological subgroups, and the denominator data were obtained from the computerised standard child-health system. The standardised perinatal mortality rate fell from 103 in 1981 to 85 in 1983, and the perinatal mortality rate fell from 15.9 to 9.4 per 1000 births in that period; 3 of the cause-specific rates declined considerably. The trend indicates an improvement in antenatal care, obstetric management, resuscitation, and care in special-care baby units. An audit in the form of a confidential inquiry contributes to an improvement in health services and a consequent reduction in perinatal mortality.

Birth Weight↗
PubMed1985

A method for determination of antibody-dependent cellular cytotoxicity (ADCC) of human peripheral mononuclear cells.

A method is described for measuring antibody-dependent cellular cytotoxicity (ADCC) of mononuclear cells from human peripheral blood using an established murine cell line and commercially prepared antisera. The test utilizes a standard 51Cr release technique. The ADCC activity of mononuclear cells obtained from 10 healthy human volunteers was measured at 4 different effector: target cell ratios. A linear relationship between %51Cr release (ADCC) and the number of effector cells was observed.

Animals↗
PubMed1985

Humoral immune response in infectious mononucleosis. Late emergence of anti-EA(R) and the effects of corticosteroid therapy.

The antibody response to Epstein-Barr virus (EBV) antigens in patients with infectious mononucleosis (IM) was studied to assess antibody appearance to the restricted (R) component of the early antigen (EA) complex and to determine the effect of corticosteroids on all aspects of the humoral immune response. Sixty college students with heterophil-positive clinical IM, confirmed by EBV-specific serology, were followed for a period of 4-26 weeks, Half received prednisone for six days, and the remainder received no corticosteroid therapy. Regardless of therapy, 48% of the patients developed anti-EA(R) antibodies. The response to other antigens was similar in both groups with the exception that antibodies to the EB-associated nuclear antigen (EBNA) developed later during convalescence and at lower titers in the corticosteroid-treated group. We conclude that 1) anti-EA(R) antibodies develop with considerable frequency following IM and are not a marker, as previously proposed, of unusually severe disease, and 2) corticosteroid therapy may retard the formation of anti-EBNA antibodies but it does not otherwise influence the humoral immune response to EBV.

Adrenal Cortex Hormones↗
PubMed1985

Nanomolar concentrations of Bowman-Birk soybean protease inhibitor suppress x-ray-induced transformation in vitro.

Experiments reported here indicate a crude soybean extract, if defatted with acetone, effectively blocks cell transformation in vitro. An active component of this crude extract is the Bowman-Birk trypsin and chymotrypsin inhibitor. The chymotrypsin-inhibitory region of the Bowman-Birk inhibitor is responsible for suppressing in vitro transformation. Another low molecular weight soybean trypsin inhibitor does not significantly suppress transformation. The Bowman-Birk inhibitor (i) has an irreversible effect on the transformation process, (ii) can suppress radiation-induced transformation even when added to cultures many days after the carcinogen exposure, and (iii) is effective in its ability to suppress transformation when present in the medium at a concentration as low as 0.125 nM.

Acetone↗