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Biomedical subjects

C B Holmes

Publications and source records attributed to C B Holmes.

At least 19 recordsLinked to original sources
PubMed2001

Diffusive growth of polydisperse hard-sphere crystals.

Unlike atoms, colloidal particles are not identical, but can only be synthesised within a finite size tolerance. Colloids are therefore polydisperse, i.e., mixtures of infinitely many components with sizes drawn from a continuous distribution. We model the crystallization of hard-sphere colloids (with/without attractions) from an initially amorphous phase. Although the polydisperse hard-sphere phase diagram has been widely studied, it is not straightforwardly applicable to real colloidal crystals, since they are inevitably out of equilibrium. The process by which colloidal crystals form determines the size distribution of the particles that comprise them. Once frozen into the crystal lattice, the particles are caged so that the composition cannot subsequently relax to the equilibrium optimum. We predict that the mean size of colloidal particles incorporated into a crystal is smaller than anticipated by equilibrium calculations. This is because small particles diffuse fastest and therefore arrive at the crystal in disproportionate abundance.

Journal Article↗
PubMed2000

The rapidity of drug dose escalation influences blood pressure response and adverse effects burden in patients with hypertension: the Quinapril Titration Interval Management Evaluation (ATIME) Study. ATIME Research Group.

BACKGROUND: Antihypertensive medication doses are typically increased within several weeks after initiation of therapy because of inadequate blood pressure (BP) control and/or adverse effects. METHODS: We conducted a parallel-group clinical trial with 2935 subjects (53% women, n=1547) aged 21 to 75 years, with Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure VI stages 1 to 2 hypertension, recruited from 365 physician practices in the southeastern United States. Participants were randomized either to a fast (every 2 weeks; n=1727) or slow (every 6 weeks; n=1208) drug titration. Therapy with quinapril, an angiotensin-converting enzyme inhibitor, was initiated at 20 mg once daily. The dose was doubled at the next 2 clinic visits until the BP was lower than 140/90 mm Hg or a dose of 80 mg was reached. RESULTS: Pretreatment BP averaged 152/95 mm Hg. Patients with stage 2 hypertension reported more symptoms than those with stage 1. The BP averaged 140/86, 137/84, and 134/83 mm Hg in the slow group compared with 141/88, 137/85, and 135/84 mm Hg in the fast group at the 3 respective clinic visits. The BP control rates to lower than 140/90 mm Hg at the 3 clinic visits were (slow, fast, respectively) 41.3%, 35.7% (P<.001); 54.3%, 51.5% (P=.16); and 68%, 62.3% (P=.02). In the fast group, 10.7% of participants experienced adverse events vs 10.8% in the slow group; however, 21.0% of adverse events in the fast group were "serious" vs only 12% in the slow group. CONCLUSION: Slower dose escalation of the angiotensin-converting enzyme inhibitor quinapril provides higher BP control rates and fewer serious adverse events than more rapid drug dose escalation.

Adult↗
PubMed1998

Oral and booklet presentation of MMPI-2.

The MMPI-2 was administered twice to college students under two formats: standard booklet administration and oral presentation, with the examiner reading the items to the students and recording their answers. The two types of administration were compared in a series of mixed-factor analyses of variance. No significant differences were found when comparing oral and booklet presentation for either men or women.

Adult↗
PubMed1998

A review of sex differences in the epidemiology of tuberculosis.

Globally, the prevalence of infection with Mycobacterium tuberculosis is similar in males and females until adolescence, after which it is higher in males. In industrialized countries in the middle of this century (1930s to 1950s), females aged 15 to 34 years had higher tuberculosis notification rates than males of the same age. However, as notification rates in these countries decreased over time, rates in males became higher than those of females for all ages over 15. Present notification rates of both sexes combined in many developing countries are similar to those of industrialized countries in the middle of the century, although the sex and age pattern is similar to that in industrialized countries at present, with men's disease rates exceeding women's after the age of 15. These findings raise the possibility that cases of tuberculosis among women are being under-reported in developing regions. This is supported by the results of a study comparing active and passive case-finding in which women with tuberculosis were under-notified to public health authorities when relying on passive case-finding. In addition, epidemiological evidence from the pre-human immunodeficiency virus (HIV) era shows that young to early-middle-aged women progress from infection to disease with greater frequency than do men. This elevated frequency of progression among women now coincides with a peak in HIV prevalence among women of the same age. National Tuberculosis Programmes must assess possible sex differences that exist in their countries. In addition, information about the risks of tuberculosis in younger women should be incorporated into maternal and child health, and HIV/AIDS programmes. Further research comparing sex differences in tuberculosis rates, preferably using active as well as passive case-finding, would be necessary to determine whether young women are undernotified in developing countries.

AIDS-Related Opportunistic Infections↗
PubMed1996

The direct effects of enflurane on coronary blood flow, myocardial oxygen consumption, and myocardial segmental shortening in in situ canine hearts.

This study evaluated changes in coronary blood flow (CBF), myocardial oxygen consumption (MVo2), and myocardial segmental shortening (SS) during intracoronary administrations of enflurane in in situ canine hearts. The left anterior descending coronary artery (LAD) of 11 anesthetized and mechanically ventilated dogs was perfused at constant perfusion pressure (80 mm Hg) with enflurane-free blood or with blood equilibrated in an extracorporeal oxygenator with enflurane (1.1%, 2.2%, 4.4%). CBF (measured with a Doppler flow transducer) was multiplied by the local arteriovenous (A-V) O2 difference to calculate MVo2. SS was measured with ultrasonic crystals. Myocardial lactate uptake was assessed. Peak CBF responses during enflurane were compared with those during maximum coronary vasodilation with adenosine. Enflurane caused concentration-dependent increases in CBF, and decreases in MVo2 and SS. The greatest increase in CBF during enflurane (4.4%) was similar to that achievable with adenosine. Myocardial lactate uptake was not affected by enflurane. In conclusion, enflurane has a direct coronary vasodilating effect. The potency of this effect is underscored by the ability of enflurane to cause marked increases in CBF, while appreciably reducing myocardial O2 demand. Since the enflurane-induced reduction in myocardial contractility was not due to ischemia, it likely reflected a direct negative inotropic effect. When the direct effects of enflurane are compared with those of equianesthetic concentrations of halothane and isoflurane previously shown in the same model, enflurane has a coronary vasodilating effect similar to that of halothane but less than that of isoflurane, and it has a negative inotropic effect greater than that of both isoflurane and halothane.

Anesthetics, Inhalation↗
PubMed1996

Retest reliability of the Wechsler Adult Intelligence Scale-Revised for 18- to 19-year-olds.

Retest reliability of the WAIS-R for 18- to 19-yr.-olds was estimated for 44 undergraduates who took the test twice with 2 to 8 weeks between testings. The mean scores on subtests and IQs and the correlations of subtest scores and IQs were similar to the values obtained by Wechsler in 1981 with only two age groups, 25- to 34- and 45- to 54-yr.-old examinees.

Adolescent↗
PubMed1995

Prevalence of head injury among four-year college students: a replication and combined results.

In a replication of an earlier study, college students were surveyed to assess the prevalence of diagnosed head injury or prolonged periods of unconsciousness. Results were consistent with previous research and indicated a significant number of college students reported a head injury or a prolonged period of unconsciousness. The major results of the two studies are reported as combined data.

Adolescent↗
PubMed1994

Use of the Draw-A-Person with conduct-disordered children.

The Draw-A-Person test was administered to 40 conduct-disordered and 40 nonconduct-disordered children and adolescents. There were 20 boys and 20 girls, ages 10 to 16 years, in each group. Two independent judges rated the drawings for presence or absence of indicators of aggressiveness that should accompany a conduct disorder, but no significant differences were found between groups or sexes.

Adolescent↗
PubMed1993

Effect of visual cues with the WAIS--R Digit Span subtest.

The WAIS-R Digit Span subtest was administered to 43 women and 31 men, ages 18 or 19 years, under standard conditions (examiner facing the person) and with the examiner sitting behind the person to eliminate possible visual cues as the examiner read the numbers. Analysis of variance of the total digits recalled indicated no differences between the sexes or between the two methods of presentation.

Adolescent↗
PubMed1989

Effects of therapist title on competence as perceived by a psychiatric sample.

A study was conducted on how perceptions of a therapist's competence are affected by the therapist's title. Psychiatric inpatients (58 males and 24 females) viewed one of four copies of a videotaped session of the interaction between a male therapist and a male client. One tape described the therapist as "Doctor," one tape described him as "Mister," one by his first name, and one with no name or title. The therapist was rated by the patients on 11 qualities related to competence. Of 11 analyses, 1 title effect was found, and females rated the therapist higher on two qualities. Overall, 9 of the qualities showed no effect for title or for ratings by gender.

Adolescent↗
PubMed1989

Effect of therapist title on perceived competence of a female therapist.

A videotaped segment of a female therapist and female client was shown to groups of male and female undergraduates (N = 278) under six conditions. At the bottom of the screen one of the following six captions was presented: Dr. (name) and client, Ms. (name) and client, Mrs. (name) and client, Miss (name) and client, First and last name and client, and no caption. The students rated the therapist on 11 variables related to competence. Females tended to rate the therapist higher, and isolated effects for title were found; however, the magnitude of the differences was so small as to suggest that no important or meaningful differences had occurred.

Adult↗
PubMed1989

Statistical versus clinical significance in research with the MMPI.

Some of the contradictions in psychological research may be attributable to failure to distinguish statistical from clinical significance. 82 articles in which the MMPI was the research instrument were analyzed to see how often the results reported as significant were in fact large enough to warrant such a conclusion. Articles were classified as to whether or not the clinical interpretations were consistent with the statistical results. Excluding articles in which data were insufficient to reach an independent conclusion, 54.90% of the articles presented conclusions of clinical significance that were not supported by the data, while 45.10% reported clinical results that were supported by the data.

Humans↗
PubMed1986

Effect of therapist's title on perceived competence.

A videotaped segment of a therapist and student/client was shown to groups of male and female undergraduates under four conditions. One group saw the tape with the title "Doctor (the therapist's actual name was used) and Client" superimposed at the bottom. The second group saw the same tape with "Mr. (blank) Client" superimposed, the third group had "Timothy (blank) and Client," while the fourth group had no title at the bottom. The 204 students rated the therapist on 11 variables. Analysis showed no effect for title and no interaction. Men rated the therapist higher on nine of the 11 variables, than did women.

Adolescent↗