Search PubMed⌕ Search

Biomedical subjects

M Polansky

Publications and source records attributed to M Polansky.

At least 19 recordsLinked to original sources
PubMed1995

Sustained arousal and attention after traumatic brain injury.

Clinicians report that patients with traumatic brain injury (TBI) often have difficulty with tasks requiring sustained attention, and there are neuroanatomical and neurophysiological reasons to expect such deficits. Nevertheless, laboratory measures of sustained attention or vigilance in TBI have produced conflicting results. These inconsistencies may be due to patient heterogeneity as well as the fact that vigilance performance is dependent on highly specific features of the task design. We developed a visual vigilance task in which the influence of non-attentional factors was minimized and task difficulty for patients and controls made comparable. Performance was characterized with respect to vigilance level as well as vigilance decrement, using measures of perceptual discrimination, response bias, reaction time and reaction time variability. Twenty-six patients with recent TBI and 18 control subjects were tested on this task. A MANOVA of ranked scores revealed significantly different patient and control performance overall. Initial level of performance (vigilance level) was slower and more variable for patients than controls, and patients showed more conservative response biases. Deterioration over time (vigilance decrement) was steeper for patients than controls for reaction time, reaction time variability, and response bias. Deterioration in accuracy (D') did not differ significantly between patients and controls. Performance was not related to available measures of injury severity. Hypotheses relating arousal mechanisms to vigilance performance are discussed.

Adolescent↗
PubMed1994

Predictors of time to healing deep pressure ulcers.

Time to healing analysis methods (Kaplan-Meier time until healing curves) were used to compare time to healing deep pressure ulcers as a function of patient and wound characteristics at baseline and after two weeks of treatment. Time to healing was significantly reduced in patients who had a good nutritional status. Patients who were alert and coherent were also found to heal more expediently; however, mental status was not independently predictive of time to healing in the multivariable model. Larger wounds took longer to heal (median 20 days) than smaller wounds, but the difference was not statistically significant. After two weeks of treatment, ulcers in patients who were 60 to 70 years old, who had a good nutritional status at baseline and whose ulcers reduced at least 39 percent in size after two weeks, were found to heal much more expediently. Cox regression models showed that these factors were independently predictive of time until healing (Likelihood ratio statistic on 5 DF = 26.485, p < 0.001). Clinical assessments, both at baseline and regular intervals thereafter, may predict treatment outcome of full-thickness pressure ulcers.

Aged↗
PubMed1992

The impact of falls in an inner-city elderly African-American population.

OBJECTIVE: To describe the impact of falls in an elderly African-American urban community and to identify predictors of poor recovery from falls. DESIGN: Prospective cohort study. SETTING: Emergency departments of 11 hospitals in western Philadelphia. SUBJECTS: Interviews were conducted with 197 African-American persons 65 years and older residing in West Philadelphia who were treated at an emergency department because of a fall. Second interviews were conducted a median of 7 months after the fall with a sample of 70 patients who had not recovered at the time of the first interview. MAIN OUTCOME MEASURES: Information abstracted from emergency department medical records and information on recovery obtained from two subsequent interviews. RESULTS: A median of 8 weeks after the fall occurred, 43% of persons reported continued pain or restriction in their usual activities as a result of the fall. Predictors of poor recovery included the presence of grandchildren in the household, hearing impairment, severity of the injury, and injury to the lower extremities. Having someone present at the time of the fall was associated with a lower risk of poor recovery. Forty-one percent of the 70 persons interviewed a second time reported continued pain or restriction in usual activities a median of 7 months after the fall occurred. However, only 7% and 39% had received the services of a home health aide or physical therapist, respectively, and only 14% reported that a physician or other health professional had been particularly helpful since the fall had occurred. CONCLUSIONS: A large proportion of elderly African-American persons treated at emergency departments for falls experience continued pain and restriction of activities after the fall. Many individuals have not recovered 7 months or longer after the fall and few persons report that a physician or other health professional has been particularly helpful since the fall occurred. We suggest that follow-up programs be developed for elderly persons in minority communities who come to emergency departments after a fall.

Accidental Falls↗
PubMed1991

The relationship between recent cocaine use and pregnancy outcome.

We conducted urine screening for cocaine metabolite in 500 consecutive women admitted to a labor and delivery unit. The pregnancy outcome of 411 of the women was determined at that admission. The prevalence of cocaine-positive urines was 15.3% (95% confidence interval 11.8-18.8%). A subset of this population that had not received prenatal care had a prevalence of 62% (95% confidence interval 47.2-76.6%). Women with positive urines were almost four times more likely to have preterm labor and over twice as likely to deliver a premature infant or one with a 1-minute Apgar score of 6 or lower. Our findings support the concept that urine drug screening for cocaine and/or other drugs of abuse should be considered in patients who present with no prenatal care, premature labor, premature delivery, and delivery of an infant with a 1-minute Apgar score of 6 or less. This strategy may enable us to identify and bring to therapy a population of women that could potentially go unrecognized.

Adult↗
PubMed1991

Blood pressure patterns in the first three days of life.

Current blood pressure data for healthy newborn infants consist primarily of single measurements of systolic and diastolic pressure in the first 48 hours of life. The purpose of this study was to determine if blood pressure levels are stable or are changing during the first few days of life. To determine blood pressure level and trend, indirect blood pressure was measured on day 1 through day 3 of life in all infants admitted to the well newborn nursery at Hahnemann University Hospital in Philadelphia. Systolic pressure correlated significantly with birthweight on day 1 of life (P less than .03). Repeated measures analysis of variance demonstrated a significant increase in both systolic and diastolic pressures over the first 72 hours of life (P less than .001). There was no difference in blood pressure among racial groups (black, Hispanic, white, Asian). In healthy newborns, there was no correlation of blood pressure with maternal conditions: toxemia, diabetes, substance abuse. These data demonstrate that blood pressure correlates with birthweight in well newborns. There is, however, a significant progressive increase in both systolic and diastolic blood pressure over the first 3 days of life, regardless of birthweight or maternal conditions.

Analysis of Variance↗
PubMed1990

Ineffectiveness of progesterone suppository treatment for premenstrual syndrome.

Progesterone is the most widely used treatment for premenstrual syndrome. To answer definitely the question of whether progesterone suppositories are effective for the treatment of premenstrual syndrome, a randomized, placebo-controlled, double-blind crossover study of 168 women, receiving progesterone in doses of 400 and 800 mg or placebo, was carried out. Premenstrual symptoms were not significantly improved by progesterone compared with placebo in any measure used in the study, including daily symptom reports maintained throughout treatment, clinician evaluation of improvement, and patient global reports of symptoms severity, relief, and disruption of daily activity. No symptom cluster or individual symptom differed significantly between progesterone and placebo treatment. These treatment results were not significantly affected by fluctuations in response during the placebo washout period, pretreatment levels of depression or anxiety at either postmenstrual or premenstrual times, or any of 19 other background, medical history, or symptom variables examined individually as covariates with treatment.

Adult↗
PubMed1989

Inhibition of 7,12-dimethylbenz[a]anthracene-initiated and 12-O-tetradecanoylphorbol-13-acetate-promoted skin papilloma formation in mice by dehydroepiandrosterone and two synthetic analogs.

Previous work has demonstrated that the adrenal steroid, dehydroepiandrosterone (3-beta-hydroxy-5-androsten-17-one, DHEA), has broad spectrum tumor chemopreventive activity in laboratory mice and rats, inhibiting the development of spontaneous breast cancer and chemically induced tumors of the lung, colon, skin, thyroid and liver. DHEA treatment produces specific side-effects, including estrogenic and androgenic action and an increase in liver weight, which could limit its use as a cancer chemopreventive drug. It is now shown that oral administration of the synthetic steroid 16 alpha-fluoro-5-androsten-17-one, which lacks the side-effects of DHEA treatment, to CD-1 mice inhibits 7,12-dimethylbenz[a]anthracene-initiated and 12-O-tetradecanoylphorbol-13-acetate-promoted skin papilloma formation at both the initiation and promotion stage. The synthetic steroid is more potent as an inhibitor of papilloma formation than comparably administered DHEA.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1988

Protein-induced glomerular hyperfiltration: role of hormonal factors.

High protein diets acutely elevate the glomerular filtration rate. To characterize this response we administered 1 g of protein/kg body weight as a beef steak meal to nine, healthy male subjects and measured glomerular filtration rate (inulin clearance), renal plasma flow (p-amino hippurate clearance), plasma renin activity, aldosterone and plasma and urinary catecholamines. The subjects ingested the meal on three separate days and were pretreated with either placebo, 50 mg indomethacin (to inhibit renal prostaglandin synthesis), or 10 mg enalapril (to inhibit angiotensin II synthesis). Following placebo treatment protein feeding significantly increased the glomerular filtration rate, from a pre-meal level of 101 +/- 7 ml/min/1.73 m2 to a post-meal level of 130 +/- 6 ml/min/1.73 m2, P less than 0.005. A parallel rise in renal plasma flow and a fall in renal vascular resistance were noted. Indomethacin pretreatment attenuated the increase in glomerular filtration rate following the protein meal, 105 +/- 6 ml/min/1.73 m2 pre-meal level to 118 +/- 4 ml/min/1.73 m2 post-meal, P greater than 0.1. Enalapril pretreatment had no significant effect on protein-induced glomerular hyperfiltration. Protein feeding following placebo increased plasma aldosterone concentration while the concentrations were unchanged in the studies where enalapril or indomethacin was administered. Protein feeding following placebo or indomethacin did not alter plasma renin activity while plasma renin activity rose following enalapril administration. Urinary norepinephrine excretion rose while plasma norepinephrine concentration was unchanged in all three study groups. A decrease in urinary dopamine excretion was also noted four hours after the protein meal was ingested.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Thermic effect of food in lean and obese men.

A systemic reappraisal of the thermic effect of food was done in lean and obese males randomly fed mixed meals containing 0, 8, 16, 24, and 32 kcal/kg fat-free mass. Densitometric analysis was used to measure body composition. Preprandial and postprandial energy expenditures were measured by indirect calorimetry. The data show that the thermic effect of food was linearly correlated with caloric intake, and that the magnitude and duration of augmented postprandial thermogenesis increased linearly with caloric consumption. Postprandial energy expenditures over resting metabolic requirements were indistinguishable when comparing lean and obese men for a given caloric intake. Individuals, however, had distinct and consistent thermic responses to progressively greater caloric challenges. These unique thermic profiles to food ingestion were also independent of leanness or obesity. We conclude that the thermic effect of food increases linearly with caloric intake, and is independent of leanness and obesity.

Adult↗
PubMed1987

A reappraisal of the caloric requirements of men.

The resting metabolic rates (RMR) of 60 lean and obese men, aged 18-82 y and weighing 60-171 kg, were measured and body compositions were determined. Body compositional variables reflecting active protoplasmic tissue were all highly interrelated. Body weight alone gave prediction values for RMR that were comparable to those of other variables of active protoplasmic tissue mass. Regional distribution of fat had no influence on the RMR and the influence of age on RMR was trivial. The classic prediction equations and tables overestimate RMR of men. The 95%-confidence limits for both lean and obese men were broad. This conclusively demonstrates that metabolic efficiency is not necessarily or exclusively related to obesity. New regression equations for predicting the RMR based on weight and fat-free mass were developed: RMR = 879 + 10.2 WT kg and RMR = 290 + 22.3 FFMD kg, where FFMD is fat-free mass from densitometry measurements.

Adult↗
PubMed1986

A reappraisal of caloric requirements in healthy women.

The caloric expenditure of 44 healthy, lean and obese women, 8 of whom were trained athletes, was measured by indirect calorimetry. Body composition was determined. Ages ranged from 18-65 yr and body weights from 43-143 kg. Stepwise, multiple-regression analysis was used to determine whether one or several variables best predicted the resting metabolic rate (RMR) of the women. The RMR and the thermic effect of food (TEF) were measured before and after the women consumed a mixed breakfast meal. The results showed that the currently available tables and regression equations overestimate the RMR of healthy women by 7-14%. Body weight was highly related to the RMR, and stepwise inclusions of various variables did not improve predictions of RMR. The slopes of the regression lines for nonathletes and athletes were significantly different. Regression equations for predicting RMR of women were developed: Nonathletes RMR = 795 + 7.18 kg WT; Athletes RMR = 50.4 + 21.1 kg WT. The range of RMR per kilogram body weight was wide for nonathletic, but narrow for athletic women. The metabolism of some lean and obese, nonathletic women was highly efficient, predisposing these women for developing and maintaining body fat. The TEFs were indistinguishable between nonathletic and athletic women, and formed a continuum from the lightest to the heaviest woman.

Adolescent↗
PubMed1986

Treatment of orthostatic hypotension with dihydroergotamine and caffeine.

Eight patients with orthostatic hypotension were treated with subcutaneous dihydroergotamine. Two doses of the drug (6.5 and 13 micrograms/kg) or placebo were given in a random sequence at 0600 h, and blood pressures were measured hourly throughout the day with patients in both supine and upright positions. To assess the effect of postprandial hypotension on the therapeutic response to dihydroergotamine, we gave breakfast, lunch, and supper on a fixed schedule at 0900 h, 1200 h, and 1700 h. Dihydroergotamine had a pressor effect in seven of the eight patients during the fasting period (0600 h to 0900 h), but this agent did not counteract the hypotensive effect of eating. Concomitant administration of caffeine (250 mg, 30 minutes before breakfast), however, maintained the beneficial effect of dihydroergotamine during the postprandial period. The combination of subcutaneous dihydroergotamine and caffeine represents a new therapeutic option for patients with severe autonomic neuropathy.

Adult↗
PubMed1985

Hepatic and renal metabolism before and after portasystemic shunts in patients with cirrhosis.

Hepatic cirrhosis with portal hypertension and gastroesophageal hemorrhage is a disease complex that continues to be treated by surgical portasystemic shunts. Whether or not a reduction or diversion of portal blood flow to the liver adversely affects the ability of the liver to maintain fuel homeostasis via gluconeogenesis, glycogenolysis, and ketogenesis is unknown. 11 patients with biopsy-proven severe hepatic cirrhosis were studied before and after distal splenorenal or mesocaval shunts. Hepatic, portal, and renal blood flow rates and glucose, lactate, pyruvate, glycerol, amino acids, ketone bodies, free fatty acids, and triglyceride arteriovenous concentration differences were determined to calculate net precursor-product exchange rates across the liver, gut, and kidney. The study showed that hepatic contribution of glucose and ketone bodies and the caloric equivalents of these fuels delivered to the blood was not adversely affected by either a distal splenorenal or mesocaval shunt. In addition to these general observations, isolated findings emerged. Mesocaval shunts reversed portal venous blood and functionally converted this venous avenue into hepatic venous blood. The ability of the kidney to make a substantial net contribution of ketone bodies to the blood was also observed.

Adult↗
PubMed1984

A classification for biomedical research reports.

Biomedical research uses a wide range of designs applied to problems in laboratory, clinical, and population settings. Whatever the nature of the study, a few key features--such as the admission rule, the method of allocating subjects to treatments, and the use of controls--largely determine the strength of scientific inferences. We used these and other features to classify the 332 Original Articles published in the New England Journal of Medicine during 1978-1979. This classification directs attention to critical aspects of study design and performance and can help in the choice of suitable research approaches and protocols. It emphasizes the critical role of the investigators' intent in performing and analyzing a study, and it alerts readers to important aspects of interpretation. We recommend that authors always report enough detail about their work for readers to apply this or a similar classification. Omission of such detail may limit the interpretation of a research study because a study that cannot be classified has probably been incompletely reported.

Clinical Trials as Topic↗
PubMed1984

Studies without internal controls.

Sometimes questions of clinical interest can be addressed only by investigations without concurrent controls that are under the supervision of the investigator (internal controls). Such studies nearly always make use of other types of comparisons (external controls), such as historical controls. In this paper we examine studies of clinical treatments that have weak internal controls or lack internal controls, as illustrated by recent examples from the Journal. These studies have a small but important and unique role in clinical investigation. Five interrelated features can add to the strength of such studies: (1) an intent by the investigator, expressed before the study, that the treatment will affect the outcomes reported; (2) planning of the analysis before the data are generated; (3) articulation of a plausible hypothesis before the results are observed; (4) a likelihood that the results would still have been of interest if they had been "opposite" in some sense; and (5) reasonable grounds for generalizing the results from the study subjects to a substantially broader group of patients. In spite of potential pitfalls, carefully selected and reported studies without internal controls can play a substantial part in the acquisition of scientific knowledge.

Animals↗
PubMed1984

Crossover and self-controlled designs in clinical research.

Crossover studies (clinical trials in which each patient receives two or more treatments in sequence) and self-controlled studies (in which each patient serves as his or her own control) can produce results that are statistically and clinically valid with far fewer patients than would otherwise be required. We investigated the use of the crossover design in the 13 crossover studies that appeared in the Journal during 1978 and 1979. We considered the following important features of design and analysis as they applied to these studies: the method by which patients were assigned to initial treatment (only 7 of 13 studies used random assignment); the determination of when to switch treatments (10 of the 13 used a time-dependent rule, and 3 a less appropriate disease-state-dependent rule); blinding of the crossover point (in only 3 of the 13 studies was the crossover point concealed, but in 4 of the remaining 10 concealment was impossible); assessment of the effects of the order of treatments (included in only 1 of the 13 studies); and the use of at least minimally acceptable statistical analysis (11 of the 13 studies had such an analysis). We also report briefly on 28 additional studies of a single treatment each, in which each patient served as his or her own control before or after treatment or both. The scientific issues were much the same as in crossover studies except that self-controlled comparisons of treatments tended to be less precisely designed and conducted and to focus on clinical problems and patient groups that are especially difficult to study.

Chronic Disease↗
PubMed1984

Inhibition of chemically induced mammary carcinogenesis in rats by short-term exposure to butylated hydroxytoluene (BHT): interrelationships among BHT concentration, carcinogen dose, and diet.

Dietary butylated hydroxytoluene (BHT) fed 14 days before and 14 days after carcinogen administration resulted in a dose-dependent inhibition of 7, 12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumor incidence in outbred Sprague-Dawley rats. In addition, the inhibitory effects of BHT were strongly influenced by the dose of initiating carcinogen and the type of diet in which BHT was administered. In animals fed the NIH-07 diet and receiving a low dose of DMBA (5 mg/rat), the inhibitory effect of BHT was manifested at all four BHT concentrations (6,000 leads to 300 ppm). Maximal inhibition was approximately 50% in animals given 5 mg DMBA and receiving 6,000 ppm BHT. However, in the group administered a high dose of DMBA (15 mg/rat), the inhibitory effect of BHT was expressed only at 6,000 ppm, the highest concentration given. Lower concentrations (300 and 1,000 ppm) of BHT had no detectable effect on tumor incidence. In animals fed the defined, semipurified AIN-76A diet during the 4-week treatment period and initiated with 5 mg DMBA, BHT at 6,000 ppm inhibited tumor development. However, at 15 mg DMBA animals fed the AIN-76A diet differed markedly from those fed the NIH-07 diet. In the former group, BHT at 6,000 ppm was unable to elicit any inhibitory response; in the latter group, BHT inhibited tumor development by 40%. Dietary BHT also inhibited DMBA-induced adrenocortical hyperplastic nodules in a dose-dependent fashion. These results indicate that short-term exposure to dietary BHT can inhibit experimental mammary tumor development at environmentally relevant concentrations.

9,10-Dimethyl-1,2-benzanthracene↗