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Biomedical subjects

R F Frankowski

Publications and source records attributed to R F Frankowski.

At least 37 records · Page 2Linked to original sources
PubMed1996

Subacute methylphenidate treatment for moderate to moderately severe traumatic brain injury: a preliminary double-blind placebo-controlled study.

OBJECTIVE: To determine the effect of subacute administration of methylphenidate on recovery from moderate to moderately severe closed head injury. DESIGN: Double-blind placebo-controlled with random assignment. Patients were enrolled when their Galveston Orientation and Amnesia Test score was at least 65. Drug/placebo treatment began the day following baseline cognitive assessment and continued for 30 consecutive days. Follow-up evaluations were conducted at 30 and 90 days after baseline, after discontinuation of drug/placebo. SETTING: A level I trauma center. PATIENTS: Twenty-three patients ranging in age from 16 to 64 years. Head injury severity ranged from moderately severe (Glasgow Coma Score [GCS] < or = 8, no intracranial pressure monitor) to "complicated mild" (GCS from 13 to 15 with positive computed tomography brain scan). Thirty-day follow-up was based on 12 patients, whereas 90-day evaluation was based on 9 patients, with complicated mild head injuries excluded from the analyses. INTERVENTIONS: Methylphenidate administered twice daily at a dose of .30 mg/kg; placebo administered according to the same schedule in identical pill form. MAIN OUTCOME MEASURES: The Disability Rating Scale (DRS) and tests of attention, memory, and vigilance. RESULTS: The methylphenidate group was significantly better at 30 days on the DRS (p < .02), and on tests of attention (p < .03) and motor performance (p, .05). No significant differences were noted between groups at 90 days. CONCLUSIONS: Subacute administration of methylphenidate after moderately severe head injury appeared to enhance the rate but not the ultimate level of recovery as measured by the DRS and tests of vigilance. Problems with possible selection bias and small sample size limit generalization of results.

Adolescent↗
PubMed1996

Maximal exercise hemodynamics and risk of mortality in apparently healthy men and women.

The purpose of this investigation was to determine the association of maximal exercise hemodynamic responses with risk of mortality due to all-causes, cardiovascular disease (CVD), and coronary heart disease (CHD) in a population of apparently healthy individuals. Study participants were 20,387 men (mean age = 42.2 yr) and 6,234 women (mean age = 41.9 yr), patients of a preventive medicine center in Dallas, TX, examined between 1971 and 1989. Maximal heart rate and maximal systolic blood pressure (SBP) measured during the maximal exercise test were related to risk of all-cause, CVD, and CHD mortality. During an average of 8.1 yr of follow-up, there were 348 deaths in men and 66 deaths in women. Among men, after adjustment for confounding variables, risks (and 95 percent confidence interval (CI)) of all-cause mortality for quartiles of maximal SBP, relative to the lowest quartile, were: 0.96 (0.70-1.33), 1.36 (1.01-1.85), and 1.37 (0.98-1.92) for quartiles 2-4, respectively. Similarly adjusted risks for maximal heart rate were: 0.61(0.44-0.85), 0.69 (0.51-0.93), and 0.60 (0.41-0.87). Similar results were seen for risk of CVD and CHD death. In women, similar trends in adjusted risks of all-cause and CVD mortality across maximal SBP and heart rate categories were observed. For maximal heart rate, a 35 bpm higher value was associated with a 36 percent decreased risk of CVD mortality in men (RR = 0.63,95 percent CI = 0.34-0.71) and an 8 percent lower risk in women (RR = 0.92,95 percent CI = 0.18-4.63). These results suggest that an exaggerated SBP or an attenuated heart rate response to maximal exercise may indicate an elevated risk for mortality in this apparently healthy population.

Adult↗
PubMed1995

Case-control study of the risk factors for eclampsia.

A case-control study was conducted to investigate risk factors for eclampsia. A total of 66 cases of eclampsia were ascertained from deliveries between 1977 and 1992 at two hospitals in Houston, Texas, based on the criteria defined by the American College of Obstetrics and Gynecology. Cases were matched to nonpreeclamptic controls on a 4:1 ratio on the basis of hospital and month of delivery. The ratio of eclampsia cases to number of deliveries over the study period was 0.63 per 1,000. In a logistic regression model, risk factors for eclampsia included 1) two or fewer prenatal care visits (odds ratio (OR) = 6.10, 95% confidence interval (CI) 2.26-16.41), 2) urinary tract infection (OR = 4.23, 95% CI 1.27-14.06), 3) primigravidity (OR = 2.87, 95% CI 0.97-8.44), 4) obesity (OR = 2.49, 95% CI 0.78-7.96), 5) black ethnicity (OR = 2.25, 95% CI 0.88-5.78), 6) history of diabetes (OR = 2.07, 95% CI 0.45-9.62), and 7) age < or = 20 years (OR = 1.55, 95% CI 0.47-5.10). Nulliparity was not shown to be a risk factor for eclampsia when controlled for primigravidity, and neither were previous history of abortion or previous history of pregnancy-induced hypertension. Thus, prior pregnancy itself, independent of outcome and preeclamptic/eclamptic complications, appears to be the protective factor against eclampsia in a subsequent pregnancy.

Abortion, Induced↗
PubMed1995

Factors related to enrollment in the breast cancer prevention trial at a comprehensive cancer center during the first year of recruitment.

BACKGROUND: Using an a priori theoretic model of behavior change, factors predicting enrollment in a randomized chemoprevention trial during the first year of recruitment were assessed prospectively. METHODS: Eligible participants were asked to complete a 90-item semistructured questionnaire after attendance at an informational meeting. Components of the Health Belief Model (including perceived susceptibility, perceived severity, perceived benefits and barriers, cues to action, and health motivation), health status, preventive health behaviors, and social influence were assessed in relation to enrollment. RESULTS: Overall, 331 women attended one of the meetings, and 73% completed a questionnaire; 45% enrolled on the trial and 55% did not. In bivariate analyses, all but one of the perceived barriers were associated negatively with enrollment; however, items assessing perceived susceptibility, perceived severity, and perceived benefits were not. Nonparticipants also were more likely to be over 49 years of age, to be currently or to have been on estrogen replacement therapy, and to have had hot flashes. In logistic regression analysis, not being able to take estrogen replacement therapy was the strongest predictor of nonparticipation (odds ratio [OR], 12.13, 95% confidence interval [CI], 3.63, 40.60). Other factors associated with nonparticipation were concern about side effects of tamoxifen (OR, 5.06; CI, 2.37, 10.80); the possibility of getting a placebo (OR, 7.75; CI, 1.51, 39.67); the costs associated with the trial (OR, 3.21; CI, 1.12, 9.24); and absence of concern that significant others would be reassured if the respondent was taking tamoxifen (OR, 2.58; CI, 1.04, 6.41). CONCLUSIONS: These findings support the view that recruitment efforts for chemoprevention trials should address barriers specific to their circumstances. In addition, increasing the support available from personal social networks may enhance recruitment to chemoprevention trials for breast cancer.

Adult↗
PubMed1995

Prediction of maximum voluntary ventilation (MVV) in African-American adolescent girls.

The purposes of the present study were to: 1) develop original equations to predict maximum voluntary ventilation (MVV) in African-American adolescent girls; and 2) determine the validity of existing MVV prediction equations for use in African-American subjects by comparing predicted MVV values in the literature with actual MVV values obtained in this study. Forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and 12 second MVV were measured with a clinical respirometer (Spirometrics model 2451) in 93 African-American adolescent girls (13.5 +/- 1.0 years). Age (r = 0.29), height (r = 0.38), FEV1 (r = 0.52), and FVC (r = 0.48) were significantly (P < 0.01) correlated with MVV. Multiple regression analysis was used to develop equations to predict MVV with age, height, and FEV1 as predictor variables. Using Mallow's Cp criterion, age-FEV1 and FEV1 equations appeared to be the most accurate predictors of MVV. When MVV was regressed on FEV1 in a non-intercept model, the result was the commonly cited equation MVV = 35.0 x FEV1. Thus, the previously established relationship between FEV1 and MVV can be extended to African-American adolescent girls. Comparison of predicted MVV values calculated from other published equations with our subjects' actual values indicated that equations using age and/or height as predictors did not accurately predict MVV in our subjects.

Adolescent↗
PubMed1991

Definition and yield of inclusion criteria for a meta-analysis of patient education studies in clinical preventive services.

Because selection of studies for a literature review influences conclusions, inclusion criteria are of utmost importance. For a meta-analysis of studies testing effects of patient education on preventive behaviors, we present the framework and concepts used for setting inclusion criteria for primary studies. We also present the yield in terms of number and distribution of studies that resulted from the inclusion criteria. Because we were interested in a diverse range of behaviors and a broad definition of patient education, we present a method for grouping behaviors by type of behavior change and describe parameters for subgrouping interventions by orientation and communication channel. Of 5,451 citations located and abstracts screened, 561 citations reporting potentially relevant studies were reviewed. Based on our inclusion criteria, 171 citations contained relevant studies, of which 64 studies (found in 62 citations) also met our acceptability criteria. We examine the effects of alternate inclusion criteria on the yield of primary studies and their distributions across the subgroupings.

Data Collection↗
PubMed1989

Environmental exposures in cytogenetically defined subsets of acute nonlymphocytic leukemia.

Three previous investigations have reported a relationship between clonal chromosome abnormalities in marrow of patients with acute nonlymphocytic leukemia and employment in occupations involving mutagenic chemicals, but the effects of other exposures were not described. Environmental exposure profiles, gathered by questionnaire, were therefore compared using a case-control study design in 235 newly diagnosed patients with acute nonlymphocytic leukemia: 126 with abnormal and 109 with normal karyotypes. The univariate odds ratio for occupation at diagnosis was 4.6, which, when adjusted for demographic and other exposures by logistic regression, was reduced to 2.5 (95% confidence interval, 0.5 to 12.8). Adjusted point estimates for other exposures were 4.3 (1.4 to 13.3) for prior cytotoxic therapy, 1.7 (0.9 to 3.1) for cigarette smoking, and 1.9 (1.0 to 3.4) for alcohol use. Dose-response relationships were present for both tobacco and alcohol consumption. Associations between specific abnormalities (+8, -7I-7q, [corrected] inv16, t[8;21]) and certain exposures were also present. These results suggest that life-style exposures may be associated with cytogenetic lesions in persons with acute nonlymphocytic leukemia.

Alcohol Drinking↗
PubMed1989

Effect of unequal censoring on the size and power of the logrank and Wilcoxon types of tests for survival data.

This paper examines the effect of random unequal censoring on the size and power of two-sample logrank and Wilcoxon types of tests for comparing two survival distributions by simulation with small samples from censored exponential distributions. We compared equal-sized samples of n = 8, 16, and 32 with 1000 (size) and 500 (power) simulation trials for 16 combinations of the censoring proportions of 0, 20, 40, and 60 per cent in each of the two samples. For n = 8, the asymptotic normality (AN), Peto-Peto, and the two Wilcoxon-type tests performed at nominal 5 per cent size expectations, but the Mantel test exceeded the 5 per cent size acceptance region in 6 of 16 censoring combinations. For n = 16 and 32, all tests showed proper size, with the Peto-Peto test being most conservative in the presence of unequal censoring. We compared powers of all tests for exponential hazard ratios of 1.4 and 2.0. The Mantal test showed 90 to 95 per cent power efficiency relative to the parametric AN test. Both Wilcoxon tests performed identically and had the lowest relative power of all tests examined but appeared most robust to the differential censoring patterns studied. A modified version of the Peto-Peto test showed power comparable to the Mantel test.

Computer Simulation↗
PubMed1988

High-dose barbiturate control of elevated intracranial pressure in patients with severe head injury.

In a five-center study, 73 patients with severe head injury and elevated intracranial pressure (ICP) were randomly assigned to receive either a regimen that included high-dose pentobarbital or one that was otherwise similar but did not include pentobarbital. The results indicated a 2:1 benefit for those treated with the drug with regard to ICP control. When patients were stratified by prerandomization cardiac complications, the advantage increased to 4:1. A multiple logistic model considering treatment and selected baseline variables indicated a significant positive treatment effect of barbiturates, a significant effect of time from injury to randomization, and an interaction of treatment with cardiovascular complications. However, of 925 patients potentially eligible for randomization, only 12% met ICP randomization criteria. The results support the hypothesis that high-dose pentobarbital is an effective adjunctive therapy, but that it is indicated in only a small subset of patients with severe head injury.

Adolescent↗
PubMed1987

Childhood nervous system tumors--an evaluation of the association with paternal occupational exposure to hydrocarbons.

Paternal occupational exposures to hydrocarbons have been associated with childhood nervous system cancer, but study results have not been consistent. This population-based case-control study was designed to examine this association using a large sample size to increase the precision of risk estimates. The birth certificates of 499 children who died in Texas from intracranial and spinal cord tumors were compared with 998 control certificates randomly selected from all Texas live births. Information on parental job title and industry at the time of birth was obtained from the birth certificates. No significant associations were identified for the dichotomized variable of all hydrocarbon-related occupations combined, as variously defined in previous studies, or for most of the specific jobs affiliated with exposures to hydrocarbons. Significant, relatively stable odds ratios (OR) were found for printers and graphics arts workers (OR = 4.5; 95% confidence interval (CI) = 1.4-14.7) and chemical and petroleum workers with high exposure levels (OR = 3.0; CI = 1.1-8.5). A discussion of the biases involved in this type of study design is presented.

Adolescent↗
PubMed1987

Neurobehavioral outcome following minor head injury: a three-center study.

The majority of hospital admissions for head trauma are due to minor injuries; that is, no or only transient loss of consciousness without major complications and not requiring intracranial surgery. Despite the low mortality rate following minor head injury, there is controversy surrounding the extent of morbidity and the long-term sequelae. The authors postulated that consecutively admitted patients who fulfilled research diagnostic criteria for minor head injury and who were carefully screened for antecedent neuropsychiatric disorder and prior head injury would exhibit subacute cognitive and memory deficits that would resolve over a period of 1 to 3 months postinjury. To evaluate this hypothesis, the neurobehavioral functioning of 57 patients was compared within 1 week after minor head injury (baseline) and at 1 month postinjury with that of 56 selected control subjects at three medical centers. Quantified tests of memory, attention, and information-processing speed revealed that neurobehavioral impairment demonstrated at baseline by all means of measurement generally resolved during the first 3 months after minor head injury. Although nearly all patients initially reported cognitive problems, somatic complaints, and emotional malaise, these postconcussion symptoms had substantially resolved by the 3-month follow-up examination. The data suggest that a single uncomplicated minor head injury produces no permanent disabling neurobehavioral impairment in the great majority of patients who are free of preexisting neuropsychiatric disorder and substance abuse.

Adolescent↗
PubMed1983

Civilian gunshot wounds: the limits of salvageability.

Patients who have suffered gunshot wounds in civilian settings, who present with posturing and in whom the bullet has passed through the geographical centre of the brain have generally not been felt to be salvageable. However, surprisingly favourable outcomes in two such patients have led us to believe that some such patients may deserve aggressive treatment.

Adolescent↗
PubMed1983

Foeto-maternal morbidity in the presence of antibodies to Trypanosoma cruzi.

Pregnancy outcome and maternal morbidity were analysed in 302 pregnant women with positive Machado-Guerreiro Complement Fixation Test (MGCFT) for antibodies to Trypanosoma cruzi and 302 women with a negative MGCFT resident of Córdoba, Argentina. A comparison of positive and negative cases was employed to investigate the association between MGCFT reaction and pregnancy outcome assessed from abortion and perinatal infant mortality rates; similarly, the data were analysed for demographic and socio-economic factors, numbers of previous pregnancies (birth order) and maternal complications. A twofold increase in the risk of pregnancy loss associated with a positive MGCFT was found. The incidence of polyhydramnios and varicosities of the leg was significantly higher in the serologically reactive group.

Abortion, Spontaneous↗
PubMed1983

Regulation of prolactin secretion in the pregnant pig: effect of fetal hypophysectomy and fetal death in small litters.

Fetal effects on prolactin secretion in late pregnancy and at term were studied in gilts with small litters of intact, hypophysectomized, partially hypophysectomized or dead fetuses. Litter size was reduced at surgery at Days 30-40 of gestation and fetal hypophysectomy or sham procedure attempted on Days 90-95 of gestation using an electrocoagulating probe. Plasma prolactin concentrations rose markedly before parturition in three gilts with normal litters (P = 0.05) and to lower peak concentrations in two gilts with a single fetus. Plasma prolactin did not change from basal concentrations in 4 gilts with small litters (1-2 fetuses) of hypophysectomized fetuses or, in 2 gilts with dead fetuses. Basal plasma prolactin concentrations were significantly lower in gilts carrying hypophysectomized or dead fetuses, compared to normal gilts (P = 0.01). A surge of prolactin secretion preceded delivery in 2 gilts with fetuses with incomplete hypophysectomy and in 1 gilt with 1 of 3 hypophysectomized fetuses. Abnormal patterns of prolactin secretion were seen in 1 gilt with 3 of 5 hypophysectomized fetuses and in 1 gilt with 1 partially hypophysectomized fetus. The results suggest that the fetus may be associated with a mechanism regulating plasma prolactin concentration at term. It is possible that this association may be by way of the fetal pituitary endocrine axes, and/or a function of conceptual mass.

Animals↗
PubMed1980

Controlled trial of aspirin in cerebral ischemia.

The findings from a double-blind multicenter clinical trial of aspirin for treatment of cerebral ischemia are reviewed. Of 303 patients who had carotid transient ischemic attacks (TIAs), 125 were selected for carotid reconstructive surgery and were then randomly assigned treatment with aspirin or placebo. The remaining 178 patients were also randomly assigned to an aspirin or placebo regimen. Analysis of the first 6 months of follow-up showed a differential in favor of aspirin when death, nonfatal cerebral or retinal infarction and the occurrence of TIAs were grouped and considered together as end points. Restriction of end points to death or nonfatal cerebral or retinal infarction yielded no statistically significant differential between the aspirin and placebo groups. After these results were published, a study group from Canada reported that aspirin was effective in preventing threatened stroke, but that this effect was limited to males. Review of our nonsurgical group with respect to sex shows findings consistent with those of the Canadian study for the end points of stroke or death. Inclusion of the occurrence of TIAs in the group of end points, however, revealed that aspirin is effective in females as well as males.

Actuarial Analysis↗