Search PubMed⌕ Search

Biomedical subjects

D S Holmes

Publications and source records attributed to D S Holmes.

At least 19 recordsLinked to original sources
PubMed1991

Construction and evaluation of a self-luminescent biosensor.

The genes encoding bioluminescence (lux genes), derived from the marine bacterium V. fischeri, have been fused next to the genes encoding mercury detoxification (mer genes), derived from a clinical isolate of S. marcescens. The fusion has been made so that the expression of the light genes comes under the control of the mer regulatory gene and promoter. These genetic elements activate the expression of the light genes in the presence of mercury. The light can readily be collected and quantitated, resulting in a biosensor for the detection of mercury.

Biosensing Techniques↗
PubMed1991

Effects of an acute bout of aerobic exercise on cardiovascular and subjective responses during subsequent cognitive work.

The experiment was conducted to test the effects of an acute bout of aerobic exercise on cardiovascular arousal and mood during a subsequent period of cognitive work. Each subject participated in two testing sessions, one that followed exercise and one that did not. In each session the subjects studied for 40 minutes, and arousal during the study period was assessed. The results indicated that prior exercise resulted in higher pulse rate (10%; p = 0.02), slightly lower systolic blood pressure (2%; p = 0.09), and higher feelings of vigor (59%; p = 0.01) than did no-exercise. The results are somewhat inconsistent with anecdotal reports concerning the effects of acute exercise, and possible reasons for the inconsistencies are discussed.

Achievement↗
PubMed1989

Selection of a specifically blocked mutant of Streptomyces cinnamonensis: isolation and synthesis of 26-deoxymonensin A.

Streptomyces cinnamonensis produces the polyether ionophore antibiotic monensin A. Following a single round of mutagenesis by UV light, a derivative of this strain has been isolated, which secretes a new metabolite identified as 26-deoxymonensin A (3). The structural elucidation of the new metabolite followed from a spectroscopic analysis, and its identity was proven conclusively following a comparison to 26-deoxymonensin A (3) obtained synthetically from monensin A. The preparation of labelled forms of 3 is described, together with incorporation experiments using the parent strain of S. cinnamonensis. Only very low levels of incorporation of 3 into monensin A were observed.

Anti-Bacterial Agents↗
PubMed1988

Direct and short-term culture preparation of chorionic villi. Is any one method best?

Chorionic villi from 20 diagnostic cases were prepared for cytogenetic analysis by a direct and two short-term culture methods. No significant differences were found between the methods in the quality and quantity of metaphases obtained. A further study using villi from 20 pre-termination patients indicated an inherent variation in the quality of villi resulting in inconsistent processing and variation in the response of a sample to the methods. This suggests that it would be advantageous to process the villi by more than one method.

Cells, Cultured↗
PubMed1988

Effects of aerobic exercise training and relaxation training on cardiovascular activity during psychological stress.

Students who reported experiencing a high number of stressful life events were randomly assigned to: (a) an aerobic training condition, (b) a relaxation training condition, or (c) a no treatment control condition. Immediately before and after the 11 week training/control period, subjects' aerobic fitness and cardiovascular responses to acute psychological stress were assessed. Results indicated that: (1) subjects in the aerobic training condition showed significantly greater improvements in aerobic fitness than subjects in the other conditions, and (2) the subjects in the aerobic training condition showed significantly greater reductions in heart rate during all phases of the stress than subjects in the other conditions. Post-training differences between aerobic and control conditions during the moderate psychological stress were as great as 17 b.p.m. These results provide evidence for the utility of aerobic training for reducing cardiovascular activity during psychological stress, and they are consistent with earlier findings linking fitness to less illness following stress, reductions in depression and enhanced recovery in cardiac patients.

Adaptation, Psychological↗
PubMed1988

Changes in personality associated with changes in aerobic and anaerobic fitness in women and men.

Thirty-nine females and 63 males participated in a 10-week physical conditioning class involving aerobic (running) and anaerobic (weight training) exercise. Aerobic fitness, anaerobic fitness, and personality were measured before and after the 10-week training period. Multiple regression analyses revealed that changes in personality were generally associated with changes in aerobic rather than anaerobic fitness, and that the relationship were most likely to be found with women. Possible explanations were offered.

Exercise↗
PubMed1988

IST2: an insertion sequence from Thiobacillus ferrooxidans.

The genome of Thiobacillus ferrooxidans (strain ATCC 19859) contains at least two families of repeated sequences, termed family 1 and 2. The nucleotide sequence of a family 2 member was determined. It is 1408 base pairs long and has structural features similar to those of insertion sequences (IS elements). Terminal inverted repeats 25 base pairs in length are present. These inverted repeats are imperfect and adjacent to target-site duplications 9 base pairs in length. Several open reading frames were detected (the longest was 888 base pairs). We have named this IS element-like sequence IST2. The ends of a second example of IST2 were analyzed and compared to those of the first. The DNA sequences are identical and similarly sized target-site duplications are present.

Base Sequence↗
PubMed1988

A study comparing transcervical with transabdominal chorionic villus sampling (CVS).

Chorionic villus sampling (CVS) was performed in 50 anaesthetized patients before therapeutic abortion by the transabdominal route and then by the transcervical route. The two methods of villus sampling were equally successful in obtaining villi but the transcervical method was significantly better at obtaining chorionic villi greater than 10 mg in weight (chi 2 13.92 P less than 0.001). Placental position did not affect villus recovery with either sampling method.

Abdomen↗
PubMed1988

Phenotypic switching of Thiobacillus ferrooxidans.

Two solid medium formulations, designated 100:10 and 10:10, were developed for the growth of Thiobacillus ferrooxidans. The new media contain a mixture of both ferrous iron and thiosulfate as available energy sources, permitting the detection of colony morphology variants that arise spontaneously in a wild-type population. Several morphological and physiological characteristics of a class of T. ferrooxidans variants, termed LSC for large spreading colony, are described. LSC variants lack the ability to oxidize iron but retain the capacity to utilize thiosulfate or tetrathionate as energy sources. An LSC colony spreads on the surface of solid 100:10 medium as a monolayer of cells in a fashion resembling that of certain swarming or gliding bacteria. The LSC variant reverts to a parental wild type at frequencies that vary in different independently arising isolates. The identity of the LSC variant as a derivative of the parental wild-type T. ferrooxidans was established by Southern blot hybridization.

Culture Media↗
PubMed1988

Spontaneous abortion rate in ultrasonographically viable pregnancies.

In a prospective study of 500 patients who had an ultrasonically viable pregnancy at less than 12 weeks' gestation, the spontaneous abortion rate was 2% overall. In those women with a history of spontaneous abortion, the abortion rate increased tenfold. Spontaneous abortion at less than ten weeks' gestation was up to three times higher than that at greater than ten weeks' gestation; this may have implications when deciding on the timing of first-trimester diagnostic procedures.

Abortion, Spontaneous↗
PubMed1987

Hard-driving and speed-impatience components of the type A behavior pattern as predictors of physiological arousal, subjective arousal and challenge seeking.

Male and female subjects first worked on a cognitive task under conditions of either low or high challenge followed by a physical exercise task. Heart rate, systolic blood pressure, diastolic blood pressure, subjective arousal, subjective fatigue, and preferred levels of challenge for subsequent tasks were assessed. The results indicated that subjects with high Hard-Driving scores reported lower subjective arousal while working on the cognitive tasks and preferred to work on more challenging cognitive and physical exercise tasks in a subsequent phase of the experiment. In contrast, subjects with high Hard-Driving scores, high Speed-Impatience scores, or high overall Type A scores did not evidence higher physiological arousal in response to either the cognitive or the physical exercise tasks. Utilization of the components of the Type A pattern yielded greater specificity of results and suggests that Type A's are at greater risk from coronary disease for reasons other than those that have been traditionally hypothesized.

Adult↗
PubMed1987

Prophylactic effect of aerobic fitness on cardiovascular arousal among individuals with a family history of hypertension.

Among normotensive individuals, a family history of essential hypertension is generally associated with elevated levels of cardiovascular arousal during stress. In contrast, aerobic fitness is associated with lowered levels of cardiovascular arousal during stress. It was therefore hypothesized that during psychosocial stress, subjects with a family history of hypertension who were aerobically fit would respond like subjects who did not have a family history of hypertension, and both of those groups would show less arousal than subjects with a family history of hypertension who were not aerobically fit. The predicted patterning of responses was found with heart rate, diastolic blood pressure and systolic blood pressure. The results are discussed in terms of the prophylactic effects of fitness for individuals with a family history of hypertension.

Arousal↗
PubMed1987

Two families of repeated DNA sequences in Thiobacillus ferrooxidans.

The genome of Thiobacillus ferrooxidans ATCC 19859 is about 2.8 X 10(6) base pairs as determined by analysis of reassociation kinetics of sheared DNA. This is 70% of the size of the genome of Escherichia coli. About 6% of the genome of T. ferrooxidans consists of moderately repetitive DNA sequences that are repeated an average of 20 times per genome. Two distinct repeated sequences, designated family 1 and family 2, have been analyzed in more detail. Both families are approximately 1 kilobase in length and are repeated 20 to 30 times per genome. Preliminary evidence from restriction enzyme analysis, Southern blotting experiments, and thermal melting analysis indicates that members of both families are conserved and are interspersed with single-copy DNA. Six copies of one family are present on the 45-kilobase-pair plasmid of strain ATCC 19859.

Chromosome Mapping↗
PubMed1986

The timing of psychosocial transitions and changes in women's lives: an examination of women aged 45 to 60.

Sixty-four middle-class women from four cohorts aged 45, 50, 55, and 60 participated in a retrospective interview concerning psychosocial changes in their adult lives. Their responses provided self-report data relating to specific psychosocial changes, and judges who read the interview protocols provided independent ratings of major psychosocial transitions. The results indicated that major psychosocial transitions were more likely to be associated with phases of the family cycle than with chronological age; within the family cycle, transitions were more likely to occur during the preschool (28% of the women), launching (42% of the women), and postparental (33% of the women) phases than during the no children, school-age, or adolescent phases; transitions associated with the preschool and launching phases were characterized by dissatisfaction, personal disruption, marital unhappiness, and decreased personal development, whereas transitions associated with the postparental phase were characterized by personal mellowing and improved marital relations; and finally, numerous self-reported psychosocial changes were associated with family cycle phase, and a small number of changes was associated with chronological age.

Age Factors↗
PubMed1986

Influence of personal and universal failure on the subsequent performance of persons with type A and type B behavior patterns.

We conducted this experiment to compare the task performance of Type A and Type B persons following failure on a task in which no one succeeded (universal failure) versus failure on a task in which others had succeeded (personal failure). Postfailure performance was measured in terms of speed of completion of anagrams. Initial analyses indicated that the failure manipulation was effective in influencing the subjects' perceived cause of their failures, and that subjects were more anxious and depressed following personal failure than universal failure. More important, we found that Type A subjects performed better following personal rather than universal failure, whereas type of failure had no effect on the performance of Type B subjects. The results suggest that contrary to what is usually thought, Type A persons do not struggle for success indiscriminately. The results are discussed in terms of need for control and self-esteem.

Achievement↗
PubMed1985

Expression of interpersonal aggression by angered and nonangered persons with the type A and type B behavior patterns.

Thirty-seven subjects with the Type A or the Type B behavior pattern were first either angered or not angered in a problem-solving task by a confederate who posed as another subject. In a subsequent bogus learning experiment, the Type A and Type B subjects had the opportunity to punish or reward the confederate. The effectiveness of the anger manipulation was attested to by the fact that angered subjects had reliably higher pulse rates, systolic blood pressure, and diastolic blood pressure. In the learning experiment, Type A subjects who had not been angered gave the confederate reliably higher levels of punishment than did Type B subjects, but there was not a difference in the levels of punishment given by Type A and Type B subjects who had been angered. There was not a difference between Type A and Type B subjects in the levels of reward they gave the confederate. The results provided behavioral evidence for aggression in persons with the Type A behavior pattern. The fact that the difference in aggression was limited to nonangered subjects was interpreted in terms of differences in attributions of responsibility.

Aggression↗
PubMed1985

The timing of psychosocial changes in women's lives: the years 25 to 45.

Sixty women, aged 30, 35, 40, and 45, participated in a retrospective interview concerning psychosocial changes in their adult lives. Subjects' responses provided self-report data concerning specific psychosocial changes, and judges who read the interview protocols provided independent ratings of major psychosocial transitions. The distributions of self-reported changes and rated transitions across both chronological age and family cycle phases were examined statistically. Rated transitions were found to be reliably related to chronological age but not to family cycle phase. Specifically, 78% of the subjects manifested a major transition commencing between ages 27 and 30. That transition was characterized initially by personal disruption, followed by reassessment and finally by increased psychological well-being. Both chronological age and family cycle phase were reliably related to a variety of self-reported changes. The implications for conceptions of adult developmental changes are discussed.

Adult↗