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Biomedical subjects

S C Choi

Publications and source records attributed to S C Choi.

At least 91 records · Page 5Linked to original sources
PubMed1987

Psychosocial impact of urinary incontinence in women.

This study explored the psychosocial impact of urinary incontinence and investigated its relationship to urodynamic diagnosis and degree of involuntary urine loss. The sample comprised 69 community-dwelling women, ages 55 years and older, who were ambulatory and mentally intact, and who had volunteered in a clinical trial on incontinence. Psychosocial impact was measured by an investigator-designed instrument, the Incontinence Impact Questionnaire. Urodynamic evaluation included detrusor and urethral sphincteric function tests. Subjects were grouped into two urodynamic diagnostic categories: sphincteric incompetence (N = 47) and detrusor instability with or without concomitant sphincteric incompetence (N = 22). Severity of incontinence was determined by a one-week urinary diary and a fluid loss quantitation test. Each of the items on the Incontinence Impact Questionnaire was affected by urinary incontinence, although to varying degrees. Activities involving unfamiliar places where the availability of restrooms was unknown were most affected. Subjects with detrusor instability with or without concomitant sphincteric incompetence reported significantly higher impact than subjects with sphincteric incompetence alone. There were modest correlations between psychosocial impact scores and both the number of weekly incontinent episodes and the quantitation of fluid loss. The results in this study population indicate that the relationships between the perceived impact of incontinence and objective measures of its severity are complex and not directly proportionate.

Aged↗
PubMed1987

Fluid loss quantitation test in women with urinary incontinence: a test-retest analysis.

A modified perineal pad-weighing method for objective quantitation of fluid loss is presented. The bladder was filled by retrograde flow, a sequence of provocative maneuvers was performed under direct supervision, and fluid loss was determined by pad weights. An analysis of immediate test-retest correlation and variability was done in patients with either sphincteric incompetence alone (N = 46) or detrusor instability with or without concomitant sphincteric incompetence (N = 21). Test-retest correlations were high in both groups, suggesting that the method could be applied as an index of severity of urinary incontinence in women. Test-retest within-patient variability was considerable, and limits its usefulness in the analysis of treatment outcome.

Adult↗
PubMed1986

Urethral axis and sphincteric function.

Position and mobility of the urethral axis are considered factors influencing urethral competence. Specific correlation between the urethral axis and its sphincteric function is lacking. Eighty-four patients with the symptom of stress urinary incontinence and 31 patients with sensory symptomatology but not urinary incontinence underwent clinical and urodynamic evaluation. This included objective assessment of urethral axial positions and mobility with use of a specially designed protractor. Comparative analysis of urethral axial data was done between 70 incontinent women with objective evidence of sphincteric incompetence and 24 continent women without it. The urethral axis at rest, during bearing down, and in its total excursion were found to be not significantly different and distributed similarly between both groups. Assessment of the urethral axis was found to be not predictive of urethral function.

Cough↗
PubMed1986

Assessment of nutritional requirements of head-injured patients.

A nomogram is presented for estimation of energy expenditure at the bedside in comatose patients during the first 2 weeks after brain injury. In analysis of 312 days of energy expenditure in 57 patients, a combination of Glasgow Coma Scale (GCS) score, heart rate (HR), and days since injury (DSI) was found with multiple regression analysis to provide good prediction of resting metabolic expenditure (RME) according to the following relationship: %RME = 152 - 14(GCS score) + 0.4(HR) + 7(DSI) (n = 111, r = 0.7, p less than 0.001). In non-comatose patients, predictive ability was less strong due to inability to measure truly rested values, but HR and GCS score could be used to predict energy expenditure by this relationship: %RME = 90 - 3 (GCS score) + 0.9 (HR) (n = 135, r = 0.47, p less than 0.001). In six patients, paralysis was found to decrease energy expenditure to between 100% and 125% of expected. Movement or stimulation had little effect on energy expenditure in patients who could localize stimuli but increased rested values by 20% in posturing patients. Analysis of fasted balance periods of nitrogen excretion in 22 patients based on 273 days of measurement showed a significant relationship between creatinine-height index (an index of muscle mass) and nitrogen excretion, but no relationship between nitrogen excretion and weight, temperature, and RME. Levels of retention of nitrogen with feeding could not be predicted by any of these variables. Feeding of the individual comatose patient is best guided at present by estimation of energy expenditure using a nomogram and periodic measurement of urinary nitrogen excretion.

Adolescent↗
PubMed1986

In vitro comparison of antiplatelet effects of beta-lactam penicillins.

beta-Lactam antibiotics have been shown to cause platelet dysfunction and bleeding in some patients. However, relative antiplatelet activity of various beta-lactams has remained controversial. Results of clinical studies have been variable because of the presence of underlying disease in the study patients, in addition to inherent difficulties of in vivo experimentation such as individual variations of drug metabolism and drug kinetics. Thus, we designed in vitro experiments to study the direct effect of penicillin G, carbenicillin, ticarcillin, mezlocillin, piperacillin, nafcillin, and azlocillin on platelets. Platelets obtained from normal volunteers were exposed in vitro for 15 minutes to increasing concentrations of the test penicillins (10.0, 12.5, 15.0, and 20.0 mmol/L), and the platelet aggregation response determined after the additional of adenosine diphosphate (2.5 to 5.0 mumol/L), epinephrine (0.1 X 10(-3) mol/L), thrombin (0.01 to 0.02 U/ml), and collagen (11.62 micrograms/ml). All tested penicillins inhibited platelet aggregation in a saturable dose-dependent manner that was reversible by platelet washing. Biostatistical comparison of inhibition of platelet aggregation demonstrated nafcillin to cause significantly more inhibition, followed by azlocillin, mezlocillin, and piperacillin as a group. Penicillin G, carbenicillin, and ticarcillin were the least inhibitory. The mean percent inhibition (epinephrine) at 20 mmol/L concentration was nafcillin 86.4%, mezlocillin 83.2%, piperacillin 80.3%, azlocillin 76.4%, ticarcillin 73.2%, carbenicillin 66.4%, and penicillin G 58.4% (overall P less than 0.001). We conclude that all penicillins tested in vitro inhibit platelet aggregation in normal individuals, but to varying degrees. The inhibitory response, which is most likely a membrane-related phenomenon, is dose dependent and reversible.

Adenosine Diphosphate↗
PubMed1985

Early decision in clinical trials when the treatment differences are small. Experience of a controlled trial in head trauma.

In a long-term clinical trial, it is customary to review the results of the data periodically. Two possible situations suggesting a possible early decision in hypothesis testing may arise. First, the difference in outcome may be sufficiently convincing without further evidence from additional data. Second, the difference may be such that it is not likely to be significant even if additional data are collected. This article is mainly concerned with a method for reaching a decision under the second situation, in particular when inadequate patient acquisition has occurred. A predicted distribution of likely future outcomes on the basis of data already accumulated is used to evaluate what might happen if the trial were carried on to the designed end. The method is intended for the case where the outcome variable is dichotomous and the two groups are compared for the difference in proportions.

Adult↗
PubMed1985

Effects of intra-animal nephron heterogeneity on studies of glomerular dynamics.

Quintuplicate determinations of the parameters measured in studies of glomerular dynamics revealed that the intra-animal coefficients of variation for Bowman's space and star vessel pressures, nephron filtration rate, and filtration fractions were 54 to 72% larger than the corresponding interanimal coefficients of variation; those for glomerular capillary pressure were more nearly equal. With a net efferent filtration pressure (delta PE) of 10.6 +/- SEM 1.9 mm Hg, the rats were far from filtration pressure equilibrium and the calculated ultrafiltration coefficient (Kf) of 2.1 +/- SEM 0.2 nl/min X mm Hg was lower than in many other studies. Statistical analysis revealed that the precision of estimates of both the measured and the derived parameters in glomerular dynamic studies is affected appreciably by ignoring the intra-animal effect. The importance of the intra-animal variance in glomerular dynamic studies is greatest when only one or two samples of each measured parameter are obtained in every rat (k = 1 or 2) and least when k is large. Triplicate sampling provides combined SEMs that are not greatly larger than those obtained with k = 5, however, and offers the greatest economy in studies of glomerular dynamics. The number of animals required to provide values with delta PE and Kf that are within +/- 20% of the "true" values is rather large.

Animals↗
PubMed1985

Computed tomography in the prediction of outcome in head injury.

To determine the prognostic significance of computed tomographic (CT) findings in head injury, retrospective analysis was performed in 128 randomly selected severe head-injury patients managed with a standardized protocol. The minimal criterion for entry into this study was that the patients were unable to obey simple commands or utter formed words. Serial CT was performed on admission and 3-5 days, 2 weeks, 3 months, and 1 year after injury. A scale of severity of abnormalities was devised taking into account the size of the traumatic lesions on CT. The CT findings using the proposed scale were correlated with the clinical outcome and analyzed using linear logistic regression. Other characteristics such as midline shift, multiplicity, and corpus callosum and brainstem lesions were not included in the analysis either because they did not affect the prognosis or because too few of these lesions were present for statistical analysis. The correct prediction rate of outcome using the proposed scale for CT findings alone was found to be 69.7%. When CT findings were combined with the Glasgow Coma Scale score this rate was increased to 75.8%.

Cerebral Hemorrhage↗
PubMed1985

Failure of prophylactic barbiturate coma in the treatment of severe head injury.

In certain subgroups of severely head-injured patients, the mortality rate remains unacceptably high. The authors describe a randomized, controlled trial of prophylactic pentobarbital therapy in a group of these patients. Pentobarbital was started as soon as possible after the head injury, regardless of the intracranial pressure (ICP), and was continued for a prescribed period of time. The study included 53 consecutive head-injured patients over the age of 12 years, who had either an acute intradural hematoma (subdural and/or intracerebral, large enough to warrant surgical decompression), or no mass lesion but whose best motor response was abnormal flexion or extension. All patients in the study were randomly assigned to a control group (26 cases) or a pentobarbital-treated group (27 cases) once the diagnosis had been made and informed consent obtained. All patients were treated with the same protocol of aggressive resuscitation, prompt diagnosis and treatment of mass lesions, and intensive care, with close follow-up monitoring. The randomization was effective in producing a close match between the control and treated groups with respect to age, sex distribution, cause of injury, neurological status, intracranial lesions, prevalence of early systemic insults, midline shift, and initial ICP. Outcome was essentially the same in each group. There was no difference between groups in the incidence of elevated ICP, the duration of ICP elevation, or the response of ICP elevations to treatment. Arterial hypotension occurred in 14 patients (54%) in the treated group and only two patients (7%) in the untreated group. Based on these data the authors cannot recommend the prophylactic use of pentobarbital coma in the treatment of patients with severe head injury. They also believe that its use is accompanied by significant side effects which can potentially worsen the condition of a patient with severe head injury.

Adolescent↗
PubMed1985

Safe use of PEEP in patients with severe head injury.

Thirty-three patients with severe head trauma were studied to determine whether the use of positive end-expiratory pressure (PEEP) would cause an increase in intracranial pressure (ICP). Changes in ICP induced by PEEP were then correlated with a panel of physiological variables to try to explain these changes. Mean ICP increased from 13.2 +/- 7.7 mm Hg (+/- standard deviation) to 14.5 +/- 7.5 mm Hg (p less than 0.005) due to 10 cm H2O PEEP, but the eight patients with elevated baseline ICP experienced no significant increase. Cardiac output and venous admixture (Qs/Qt) declined significantly, while central venous pressure, peak inspiratory pressure, functional residual capacity, and arterial pCO2 increased significantly due to PEEP. Blood pressure and cerebral perfusion pressure were unchanged. The change in ICP due to PEEP correlated significantly with a combination of cardiac output, peak inspiratory pressure, Qs/Qt, and changes in blood pressure and arterial pCO2 due to PEEP, indicating that the effect of PEEP on ICP could be largely explained by its effect on hemodynamic and respiratory variables. No patient deteriorated clinically due to PEEP. It is concluded that 10 cm H2O PEEP increases ICP slightly via its effect on other physiological variables, but that this small increase in ICP is clinically inconsequential.

Brain Injuries↗
PubMed1985

Effect of diabetes on microvascular responses in mouse mesentery.

Mice 8 weeks old were made diabetic with streptozotocin. Their mesenteric arterioles were studied 4-8 weeks later and their responses compared with those of arterioles in control mice. The responses to the dilators acetylcholine and papaverine and to the constrictor prostaglandin F2 alpha were identical in diabetics and controls whether the changes in diameter were expressed as a percent of baseline diameter or in absolute units (microns). Diabetics had significantly smaller responses than controls, to the constrictors norepinephrine and serotonin. However the effect of diabetes on the response to norepinephrine may have been a spurious consequence of expressing constrictions as a percent of slightly differing resting diameters, since the difference became statistically insignificant when constrictions were expressed in absolute units as microns. The reduced response to serotonin remained significant no matter how constriction was expressed. This result, together with a similar finding in an earlier study of diabetes which used much smaller cerebral vessels, suggests that reduced vascular responses to serotonin may be associated with streptozotocin diabetes of relatively recent onset in mice. The reason for this relatively selective impairment of vasomotor response remains obscure, as does the reason for the spared responses to the other vasoactive agents we tested.

Animals↗
PubMed1984

Arrhythmias on ambulatory electrocardiographic monitoring in women without apparent heart disease.

Cardiac arrhythmias were evaluated in apparently normal women by randomly selecting within the age decades of 20 to 60, 200 of the 788 women employees of a company. After exclusions for cardiac and medical reasons and refusals to participate, 101 subjects underwent 24-hour ambulatory electrocardiographic monitoring. The mean heart rate was 82 beats/min, but was higher in smokers (p less than 0.05). Premature supraventricular contractions were present in 28 of 101 subjects (28%); the prevalence increased with age (p less than 0.001), but the frequency was less than 1 per hour in 24 of 28. PVCs occurred in 34 of 101 subjects (34%); the frequency was less than 1 per hour in 25 of 34. The PVCs were complex (Lown grade 3 or higher) in 10 (10%) and multifocal in 9 of 10; there was 1 couplet each in 3 and 1 run of 4 PVCs in 1 subject. PVCs were present in 20 of 42 subjects (48%) taking any medication (primarily oral contraceptives, estrogenic hormones and maintenance thyroid), compared with 14 of 59 subjects (24%) not taking medication (p less than 0.01). In women younger than 40 years, PVCs were present in 8 of 15 women (53%) taking contraceptives, compared with 4 of 33 (12%) not taking contraceptives (p less than 0.001). PVCs occurred in 7 of 12 subjects (58%) taking thyroid medication, compared with 27 of 89 (30%) not taking thyroid medication (p less than 0.03). In the 59 subjects not taking medication only 1 subject averaged more than 1 PVC/hour and 1 had 1 couplet.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Effect of changes in magnesium ion concentration on cat cerebral arterioles.

The effect of changes in cerebrospinal fluid (CSF) concentration of magnesium ion ([Mg2+]) on pial arterioles was investigated in anesthetized cats equipped with acutely implanted cranial windows for the observation of the pial microcirculation. Increased [Mg2+] caused vasodilation, whereas decreased [Mg2+] caused vasoconstriction. The effect of [Mg2+] was dose dependent and was the same in small and larger arterioles. There was an interaction between CSF [Mg2+] and calcium ion concentration ([Ca2+]), such that the vasodilator effect of Mg2+ was greater when the [Ca2+] was lower, especially in larger vessels. The vasodilator effect of Mg2+ on pial arterioles was enhanced in the presence of the calcium antagonist verapamil (0.5 micrograms/ml), despite the fact that verapamil by itself caused a 12-13% arteriolar dilation. These results show that the vasodilator effect of Mg2+ is probably related to an interaction at the cell membrane resulting in reduction in the influx of Ca2+ into vascular smooth muscle.

Animals↗
PubMed1983

Chart for outcome prediction in severe head injury.

An analysis of clinical and demographic data of 264 patients with severe head injury showed that a combination of the Glasgow Coma Scale (GCS) score, oculocephalic responses, and age can provide a simple but reliable prediction of outcome in severe head injury. Addition of other clinical data, excluding intracranial pressure and evoked potentials, improved the predictability only negligibly. A simple chart, which is constructed from the application of the logistic regression model, can be used to determine the odds of a good outcome from the combination of the three factors. A method is given by which the GCS score of a patient with a missing verbal response score can be accurately approximated in order to complete the chart. Among other values, the odds of a good outcome provide the clinician with a reliable measure of the relative severity of a patient's injury. The accuracy of the chart in prediction is expected to be 80% or above.

Adult↗
PubMed1982

Aryl sulfatase A in acute nonlymphocytic leukemia.

To ascertain whether estimation of urinary aryl sulfatase A (ASA) is a reliable noninvasive technique for monitoring disease activity in adult acute nonlymphocytic leukemia, we studied the excretion pattern of this enzyme during active disease, partial remission, and complete remission in ten patients and compared the results with those of ten healthy volunteers. There was no significant difference in enzyme excretion between complete remission cases and the control group. Patients with partial remission and active disease had significantly different urinary enzyme levels from each other and from the control and complete remission groups. Estimation of urinary ASA is a useful noninvasive method of monitoring disease activity in adult acute nonlymphocytic leukemia.

Acute Disease↗
PubMed1982

The effect of tranylcypromine on levels of 6-keto-PGF1 alpha and other prostaglandins in brain and mesentery of the mouse.

Tranylcypromine (TCP), which can inhibit prostacyclin (PGI2) synthesis in vitro, has been shown to facilitate platelet aggregation in damaged cerebral arterioles of the mouse when given intraperitoneally (50 mg/kg) one hour before inducing aggregation. The same dose has no effect on platelet aggregation in damaged mesenteric arterioles. The present experiments used HPLC and GC/MS to analyze PG levels and show that 5 or 50 mg/kg TCP, given intraperitoneally one hour before sacrificing the mouse, moderately reduces the level of 6-keto-PGF1 alpha, the stable metabolite of PGI2, in incubated brain homogenates. This finding supports the hypothesis that TCP's enhancement of platelet aggregation in the brain was affected by a reduction in PGI2 levels. When 500 micrograms/ml TCP was added to the incubate of brain homogenate from mice given 50 mg/kg, PGE2 levels were reduced as well as the levels of 6-keto-PGF1 alpha. In incubated mesentery, the level of 6-keto-PGF1 alpha was also reduced by treating mice with 50 mg/kg TCP. The latter result failed to support the hypothesis that levels of mesenteric 6-keto-PGF1 alpha would be unaltered by TCP in parallel with the inability of TCP to alter platelet aggregation in mesenteric arterioles. Thus our data fails to support an overall hypothesis relating TCP action on platelet aggregation to its inhibitory effect on PGI2 synthesis. At the same time the data do not rule out such a relationship for mouse brain.

Animals↗