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Biomedical subjects

C Adams

Publications and source records attributed to C Adams.

At least 19 recordsLinked to original sources
PubMed1992

A comparative study of pH/activity profiles for the anaerobic H2O2 and alkyl hydroperoxide supported N demethylation of N methylaniline catalyzed by alkaline haematin and microsomal cytochrome P-450.

A comparative study of the effect of pH on haemin-mediated H2O2 and alkyl hydroperoxide-supported N-demethylation of N-methylaniline and the corresponding cytochrome P-450 mediated process has been carried out. This extends previous studies and provides quantitative evidence that the same active oxygen species are involved in both the enzymic and metalloporphyrin mediated processes. Furthermore, this evidence clearly indicates that the environment at the point of catalysis in the enzyme active site differs considerably from that of the bulk solution.

Anaerobiosis↗
PubMed1992

Comprehension problems in children with specific language impairment: literal and inferential meaning.

A group of 61 schoolchildren with specific language impairment (SLI) was compared with a control group on a comprehension task, in which the child was questioned about a story that had been presented either orally or as a series of pictures. Half the questions were literal, requiring the child to provide a detail that had been mentioned or shown explicitly in the story. The remainder required the child to make an inference about what had not been directly shown or stated. SLI children were impaired on this task, even after taking into account "comprehension age," as assessed on a multiple-choice test. However, the effects of mode of presentation and question type were similar for control and SLI groups. Children who fitted the clinical picture of semantic-pragmatic disorder had lower scores than other SLI children on this task. In addition, they were more prone to give answers that suggested they had not understood the question. However, as with the other SLI children, there was no indication that they had disproportionate difficulty with inferential questions. It is concluded that SLI children are impaired in constructing an integrated representation from a sequence of propositions, even when such propositions are presented nonverbally.

Child↗
PubMed1992

Flagellar microtubule dynamics in Chlamydomonas: cytochalasin D induces periods of microtubule shortening and elongation; and colchicine induces disassembly of the distal, but not proximal, half of the flagellum.

To study the mechanisms responsible for the regulation of flagellar length, we examined the effects of colchicine and Cytochalasin D (CD) on the growth and maintenance of Chlamydomonas flagella on motile wild type cells as well as on pf 18 cells, whose flagella lack the central microtubules and are immobile. CD had no effect on the regeneration of flagella after deflagellation but it induced fully assembled flagella to shorten at an average rate of 0.03 microns-min. Cells remained fully motile in CD and even stubby flagella continued to move, indicating that flagellar shortening did not selectively disrupt machinery necessary for motility. To observe the effects of the drug on individual cells, pf 18 cells were treated with CD and flagella on cells were monitored by direct observation over a 5-hour period. Flagella on control pf 18 cells maintained their initial lengths throughout the experiment but flagella on CD-treated cells exhibited periods of elongation, shortening, and regrowth suggestive of the dynamic behavior of cytoplasmic microtubules observed in vitro and in vitro. Cells behaved individually, with no two cells exhibiting the same flagellar behavior at any given time although both flagella on any single cell behaved identically. The rate of drug-induced flagellar shortening and elongation in pf 18 cells varied from 0.08 to 0.17 microns-min-1, with each event occurring over 10-60-min periods. Addition of colchicine to wild type and pf 18 cells induced flagella to shorten at an average rate of 0.06 microns-min-1 until the flagella reached an average of 73% of their initial length, after which they exhibited no further shortening or elongation. Cells treated with colchicine and CD exhibited nearly complete flagellar resorption, with little variation in flagellar length among cells. The effects of these drugs were reversible and flagella grew to normal stable lengths after drug removal. Taken together, these results show that the distal half to one-third of the Chlamydomonas flagellum is relatively unstable in the presence of colchicine but that the proximal half to two-thirds of the flagellum is stable to this drug. In contrast to colchicine, CD can induce nearly complete flagellar microtubule disassembly as well as flagellar assembly. Flagellar microtubules must, therefore, be inherently unstable, and flagellar length is stabilized by factors that are sensitive, either directly or indirectly, to the effects of CD.

Actins↗
PubMed1992

Mutant lambda repressors with increased operator affinities reveal new, specific protein-DNA contacts.

The binding specificities of four mutant lambda cI repressor proteins with increased affinities for operator DNA were examined. Two mutant repressors (Glu34----Lys and Glu83----Lys) have the same specificity of binding as wild-type repressor, whereas two (Gly48----Ser and Gly48----Asn) have new binding specificities. The Gly48----Asn mutant repressor recognizes lambda operators with changes at base pair 3 with a different order of affinity than wild-type repressor, suggesting that the side chain of Asn48 makes additional specific DNA contacts at or near this base pair. When paired with a change that disrupts the specific interaction of the amino-terminal arm of lambda repressor with DNA (Lys4----Gln), one change that increases the affinity of repressor (Gly48----Ser) suppresses the binding defect of the Lys4----Gln repressor, resulting in a double mutant repressor with a new binding specificity different than that of both its parents and of wild type. These results lend strong support to the model of direct recognition of the lambda operator by lambda repressor proposed from the crystal structure of the repressor/operator complex.

Bacteriophage lambda↗
PubMed1992

[Left ventricular dilatation after primary transmural anterior myocardial infarction. Influence of the percentage of akinesia on echocardiography].

The aim of this study was to determine whether the percentage of akinesia on echocardiography during the acute phase of transmural anterior myocardial infarction could predict secondary left ventricular dilatation. The study group comprised 24 patients (18 men and 6 women) with an average age of 59 years. The patients underwent two echocardiographic examinations, the first during the acute (< 72 hours) phase and the second, 6 months later. Ventricular volumes were calculated by the ellipse monoplane method in the apical 4 chamber view. The percentage of akinesia was defined as the ratio between the length of the akinetic segment and the left ventricular end diastolic perimeter in the apical 4 chamber view. An increase in end diastolic volume (83 +/- 25 vs 62 +/- 18 ml/m2; p < 0.01) and in end systolic volume (51 +/- 27 vs 34 +/- 11 ml/m2; p < 0.01) was observed 6 months after infarction without a significant change in ejection fractions (42 +/- 17% vs 44 +/- 10%). The percentage of akinesia in the acute phase was > 30% in 15 patients (Group I) and < 30% in 9 patients (Group II). The increase in ventricular volumes at 6 months after infarction was significant in Group I (p < 0.02) but not in Group II. At 6 months after infarction, the end systolic volumes were greater (60 +/- 27 vs 37 +/- 22 ml/m2, p < 0.5) and the ejection fractions were lower (35 +/- 13% vs 53 +/- 18%, p < 0.01) in Group I than in Group II.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Superiority of end-diastolic volume and ejection fraction measurements over wedge pressures in evaluating cardiac function during aortic reconstruction.

Marked changes occur in cardiac function during aortic reconstruction. Numerous factors (primarily compliance changes) limit the currently used pressure-based pulmonary artery catheters' ability to reflect these changes accurately. A new pulmonary artery catheter was used in 26 patients undergoing aortic reconstruction (7 patients with abdominal aortic aneurysms and 19 with occlusive disease) that directly measures right ventricular (RV) volumes and ejection fractions. The extent of coronary artery disease (CAD) was evaluated before surgery, and the patients were divided into three classes. The greatest changes in cardiac function were noted immediately after aortic cross-clamping. Cardiac output significantly decreased in patients with mild or moderate CAD (p less than 0.01 and p less than 0.001) but not in patients with no CAD (p less than 0.5). This correlated well with RV end-diastolic volume (RV-EDV) and stroke volume (RV-SV) measurements in the groups with mild (p less than 0.05) and moderate CAD (p less than 0.01) but not in the group with no CAD (p greater than 0.5). Wedge pressure showed poor correlation, with no significant change noted in any group (p greater than 0.5). Measurements taken later in the procedure documented a significant trend toward baseline in mild and moderate groups. At the opening of the second limb of the graft, the compensated values (CO, RV-EDV, and RV-SV) did not change significantly in the groups with mild and no CAD (p greater than 0.2) but approached significance in the group with moderate CAD (p less than 0.08).(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta, Abdominal↗
PubMed1991

Calvarial thinning in low grade intracerebral gliomas presenting with epilepsy.

Intracranial gliomas can erode or thin the skull. These changes are detectable on conventional radiographs but they appear to be rare. Only a few examples of the appearances on computed tomography (CT) are recorded in the literature. This paper describes the CT appearances of 11 cases. All of the patients presented with epilepsy. In most the tumours were small and indolent. Some went undetected or misdiagnosed for several years because of a lack of familiarity with the appearances.

Adolescent↗
PubMed1991

Qualitative age differences in memory for text: a life-span developmental perspective.

Qualitative differences in memory for text among 4 age groups (mean ages = 14.14, 17.55, 48.35, and 67.12 years) were examined in this study. Participants produced written recall and summary responses after presentation of a story and an essay. The response protocols were scored for their reproductive, elaborative, and metaphoric content. Age-group differences were observed in the quality of the responses. In general, the adolescent recall and summary responses were reproductive and text based, whereas the adult responses were more reconstructive and interpretive. Age-group differences were especially apparent in the story condition: The adolescents recalled and summarized the story's propositional content, whereas many of the adults recalled and summarized the story's psychological and metaphoric meanings as well. Individual difference variables accounted for much of the age-related variability in the essay but not in the story responses.

Adolescent↗
PubMed1991

[Bacteriological quality of groundwaters in cemeteries].

Groundwater samples collected by piezometers from three cemeteries in geologically distinct areas of S. Paulo and Santos, Brazil, were analysed in order to determine their hygienic and sanitary conditions. Fecal coliformes, fecal streptococci, sulfite reducer clostridia and Salmonella were searched for the purpose of evaluating sanitary conditions, and total coliforms, heterotrophic bacteria, proteolitic and lipolitic microorganisms for evaluating hygienic conditions. In some samples, nitrate levels were also determined. It was discovered that these waters do not present adequate sanitary and hygienic conditions and that, in some cases, nitrate levels were extremely high (75.7 mg/l). In most samples, higher levels of fecal streptococci and sufite reducer clostridia than fecal coliforms were detected, which seems to show that the two former indicators would be more appropriate for evaluating the sanitary conditions of this kind of water. Salmonella were detected in only one of 44 samples analysed and coliphages in none. In the statistical analysis, the correlation matrix showed significant correlations among three fecal pollution indicators, as well as among anaerobic and aerobic heterotrophs and lipolitic bacteria. A direct relationship between the deterioration of water quality and the geological and hydrogeological conditions of the environment studied was observed. When cemeteries are constructed these conditions should, therefore, be taken into consideration.

Clostridium↗
PubMed1991

[Myocardial bridge of the left anterior descending coronary artery and myocardial infarction: does coronary spasm play a part?].

The association of a myocardial bridge of the left anterior descending (LAD) coronary artery and myocardial infarction is rare. The mechanisms by which the myocardial bridge could predispose to myocardial infarction are tachycardia (reducing the duration of diastolic coronary filling), thrombosis at the site of the myocardial bridge, and coronary spasm which, however, has never been demonstrated in the context of infarction. The aim of this study was to detect coronary spasm by provocative ergometrine testing in 4 patients, all male, aged 21 to 49 years, average 39 years old, who had anterior myocardial infarction associated with myocardial bridging of the LAD artery without atheromatous coronary stenosis. The ergometrine tests were performed during (2 cases) or after coronary angiography (2 cases). The systolic narrowing due to the myocardial bridge ranged from 25 to 95% (average 70%). The ergometrine test was strongly positive in 1 patient and negative in the other 3. Repermeabilisation of a thrombus was suggested in these 3 patients by the recording of an accelerated idioventricular rythm in the acute phase of infarction (2 cases) or by the demonstration of abnormal platelet aggregation (1 case). This is the first report of coronary spasm in a patient with myocardial bridging associated with infarction. However, it is not possible to determine the respective roles of spasm and myocardial bridging in the genesis of the infarct. We suggest systemic provocative ergometrine testing in this situation to orientate the most appropriate treatment.

Adrenergic beta-Antagonists↗
PubMed1991

An analysis of school nurse leadership styles.

New programs, such as care of pregnant teens and substance abuse education, are more commonplace in the school setting today. The school nurse is increasingly involved with professionals and others inside and outside the school system. Thus, the nurse's effectiveness may greatly depend upon the ability to lead others.

Female↗
PubMed1991

Inter-observer variability in the measurement of body composition.

The inter-observer variation in simple bedside assessments of body composition has been evaluated in 12 healthy adult subjects (6 male and 6 female) by 6 observers. Systematic bias between observers was found to be evident in each of the basic measurements (except height) and in each of the estimates of body composition (except those derived from weight and height alone). The largest residual coefficients of variation (rCV) for the basic measurements were found for skinfold thickness (11-18 per cent for individual skinfold thicknesses, and 9 per cent for the sum of four skinfold thicknesses), and the lowest for weight (0.01 per cent for digital scales, and 0.05 per cent for beam balance) and height (0.4 per cent). The rCV for whole-body resistance (1.2 per cent), forearm resistance (5.4 per cent) and near infra-red interactance (optical density 1: 5.6 per cent and optical density 2: 6.2 per cent) measurements were found to have intermediate values. The variability in the estimate of body fat obtained by skinfold thickness (rCV = 4.6 per cent) and near infra-red interactance methods (rCV = 4.2 per cent) was found to be greater than that from the resistance method (rCV = 2.6 per cent) and by methods based on weight and height alone (rCV = 1.1 per cent). The variability in the estimate of fat-free mass showed the same trend as that for body fat, but the rCVs were less due to the greater mass of the fat-free body compared to body fat.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The relationship between neuropsychological measures and self-care skills in patients with cerebrovascular lesions.

The present investigation examined the relationship between performance on the Michigan Neuropsychological Battery (MNB) and selected self-care skills in a group of patients with unilateral cerebrovascular lesions. Among MNB measures, left-sided somatosensory and motor functions were the best predictors of self-care skills, showing that in these stroke patients lower level cerebral functions mediated by the right hemisphere are more strongly related to the self-care skills examined than higher cerebral functions. Also, evidence that patients with cerebrovascular lesions in the left hemisphere performed better than patients with right hemisphere lesions in several self-care categories is further indication that right hemisphere processes have a special role to play in the mediation of these self-care activities. The research and clinical implications of these findings are noted.

Activities of Daily Living↗
PubMed1990

Silastic prosthesis plombage for right postpneumonectomy syndrome.

In rare instances, right pneumonectomy can produce progressive exertional dyspnea and reduce ventilatory reserve because of extreme mediastinal shift (right postpneumonectomy syndrome). The diagnosis can be made by bronchoscopy and computed tomography. We report a case of a 43-year-old patient in whom plombage with two Silastic breast implants produced mediastinal derotation and symptomatic relief of this syndrome.

Adenocarcinoma↗
PubMed1990

Acute transverse myelopathy in children.

Twenty-three children with acute transverse myelopathy (ATM) are reviewed. Antecedent minor trauma or exercise was reported in 10 patients. Despite a positive history in 7 patients no preceding infection was documented. Two patients had a history of less severe ATM followed by recovery prior to a second more severe episode. The most common initial symptom was back pain and the most prominent clinical signs were weakness, sensory level and sphincter disturbances. Myelography and CT myelography at presentation was performed to exclude a compressive lesion. Spinal cord enlargement was demonstrated in 6 of 21 cases. Magnetic resonance imaging (MRI) of the spinal cord, performed in one patient, showed enlargement of the cord. Poor prognostic features were severity of weakness at the time of maximum deficit and a delayed onset of recovery. Maximum motor recovery occurred at a mean of 6 1/2 months but did not occur in one patient until 1 1/2 years. Normal or good outcome was obtained in 64%.

Acute Disease↗