Biomedical subjects

D K McClish

Publications and source records attributed to D K McClish.

At least 37 records · Page 2Linked to original sources

PubMed1997

Bacteremia in young urban women admitted with pyelonephritis.

The objective of this study was to determine the rate of bacteremia in young women admitted to the hospital with presumed pyelonephritis and compare it with other published rates. The study design was a retrospective, structured chart review and a review of published reports of bacteremic pyelonephritis. An urban county teaching hospital provided the setting for the study. The patients were nonpregnant women (n = 98) 44 years of age or younger who were without bladder dysfunction and who had not been admitted to an intensive care unit. Further criteria for participation included discharge with the diagnosis of acute pyelonephritis. Blood cultures were ordered for 69 women; the results of 64 were noted in the chart. Twenty-three women (35.9% of those cultured; 23.4% of all patients) were diagnosed with bacteremia. In patients for whom blood culture results were obtained, trends developed between those patients with bacteremia and those with complicated pyelonephritis, defined as a known or newly discovered genitourinary abnormality or a risk factor (P = 0.044), those who were black (P = .044), those with higher pulses on admission (P = .050), those with more white blood cells per high-powered field after urinalysis (P = 0.007), and those whose fever lasted longer (P = 0.033). Blood culture results were positive in two patients whose urine cultures were negative. This comparatively high bacteremia rate supports routine ordering of blood cultures for urban women suspected of having pyelonephritis.

Adolescent↗

PubMed1997

Physicians' judgments of the risks of cardiac procedures. Differences between cardiologists and other internists.

OBJECTIVES: The authors compared judgments of the population risks of invasive cardiac procedures made by cardiologists and other internal medicine physicians. Our main hypotheses were that cardiologists' judgments would differ from those made by the other physicians and that cardiologists' judgments would be more accurate than those of other physicians. METHODS: This was a cross-sectional survey of senior staff and physician-trainees at two teaching hospitals affiliated with a US medical school, Emergency Department physicians at a community hospital in the same metropolitan area, and senior staff and trainees at two teaching hospitals affiliated with a UK school. Judgments of the risks of severe morbidity and death due to Swan-Ganz catheterization, cardiac catheterization, percutaneous coronary angioplasty, and coronary artery bypass grafting were assessed. RESULTS: Nineteen cardiologists judged the risks of severe morbidity due to all procedures and the risks of death due to all procedures except coronary artery bypass grafting to be significantly lower than did the 78 other internists. Cardiologists more frequently made accurate judgments of the rates of morbidity and death due to cardiac catheterization than did the other internists; other internists more frequently made accurate judgments for the rates of morbidity due to Swan-Ganz catheterization. CONCLUSIONS: Disagreements about the risks of procedures may arise from a paucity of published data, or from an over-supply of confusing data.

Angioplasty, Balloon, Coronary↗

PubMed1996

Comparison between urinary diaries completed with and without intensive patient instructions.

The evaluation of the incontinent patient relies on accurate assessment of urinary symptoms. Although the 7 day urinary diary is a reproducible method of data collection, the optimal means of implementing this diary is unknown. The urinary diary is usually employed after the initial clinical pathophysiologic evaluation has been performed and the patient has received intensive instructions on the correct method of diary completion. This study aims to determine if a urinary diary provided to the patient prior to the initial clinical evaluation along with minimal instructions will provide symptom data comparable with that obtained by conventional methods. Two hundred seventy-eight women were recruited to participate in one of three clinical trials for urinary incontinence treatment. All subjects completed a diary prior to the initial clinical evaluation, the Minimal Instruction Diary, and a second diary after clinical evaluation, the Intensive Instruction Diary. The Minimal and the Intensive Instruction Diaries were compared for number of episodes of diurnal and nocturnal voluntary micturition and incontinence. Pearsons' correlation coefficients ranged from 0.67 to 0.78 for each of the urinary symptoms. Intra-subject comparison indicated a decline in reports of nocturnal voluntary micturitions from the Minimal to the Intensive Instruction Diary. No demographic or urodynamic parameters could account for the difference. The 7 day urinary diary is a reliable tool to asses urinary symptoms, which can be utilized prior to the initial clinical evaluation. Its case of use and practicality make this diary promising for use in a wider patient population.

Aged↗

PubMed1996

Efficacy of estrogen supplementation in the treatment of urinary incontinence. The Continence Program for Women Research Group.

OBJECTIVE: To assess the efficacy of cyclic postmenopausal hormone replacement in treating urinary incontinence in hypoestrogenic women. METHODS: Eighty-three hypoestrogenic women complaining of urinary incontinence were included. All patients were community-dwelling, age 45 years or older, with involuntary loss of urine occurring at least once a week and urodynamic evidence of genuine stress incontinence and/or detrusor instability. Evaluation consisted of a comprehensive clinical and urodynamic research protocol. The hypoestrogenic entry criterion was a plasma estradiol level of 30 pg/mL or less. Parabasal cells on vaginal smears were also monitored. The primary outcome was the number of incontinent episodes per week, as documented on a standardized urinary diary. Secondary outcomes were the quantity of fluid loss, voluntary diurnal and nocturnal micturition frequency, generic and condition-specific health-related quality of life measurements, and patient satisfaction. A randomized, placebo-controlled, double-blind design was used. Subjects in the treatment group were given conjugated equine estrogens (0.625 mg) and medroxyprogesterone (10 mg) cyclically for 3 months. Controls received placebo tablets. RESULTS: (All results are presented as mean +/- standard deviation.) Subjects were 67 +/- 9 years old. The menopause duration was 18 +/- 11 years. The duration of incontinence was 9 +/- 9 years. Estradiol level at baseline was 9 +/- 9 pg/mL, and the parabasal cell count was 42 +/- 44%. The number of incontinent episodes at baseline was 13 +/- 10 for the treatment group and 16 +/- 4 for controls. No significant changes occurred in the number of incontinent episodes after treatment: 10 +/- 10 for the treatment group, and 13 +/- 14 for the controls (P = .7). Also, fluid loss was not changed: 176 +/- 106 g for the treatment group and 64 +/- 88 g for the control group at baseline, and 101 +/- 150 and 51 +/- 69 g after treatment, respectively (P = .7). There were no significant differences for either diurnal or nocturnal voluntary micturition, quality of life measures, or patient's perception of improvement. CONCLUSION: Three-month cyclic hormone replacement therapy did not affect either clinical or quality of life variables of incontinent, hypoestrogenic women. Long-term effects are unlikely to be substantially different. The use of estrogen supplementation as preventive or adjuvant therapy was not evaluated in this study.

Aged↗

PubMed1996

Prediction of survival of critically ill patients by admission comorbidity.

The objective of this study was to determine how well the Charlson index of comorbidity would predict mortality of critically ill patients; and how the predictive ability of the index would compare with that of the comorbidity component (Chronic Health Points) of the APACHE II system. This prospective cohort study included in its setting an intensive care unit (ICU) and intermediate ICU (IICU) in a teaching hospital. Patients included a previously assembled inception cohort of 201 patients consecutively admitted to either unit, followed until death or discharge from the hospital, excluding patients admitted after coronary artery bypass grafting, for planned dialysis, or transferred to the IICU from another intensive care unit. Main outcome measures were recorded as death in hospital versus survival at discharge. For each patient we had prospectively obtained all data necessary to predict the probability of in-hospital death using the APACHE II system, and to classify comorbidity using the Charlson index. The Charlson index had significant ability to discriminate between patients who would live and who would die (ROC curve area = 0.67, SE = 0.05). The Chronic Health Points component of APACHE II had no significant discriminating ability (ROC area = 0.57, SE = 0.05), although the full APACHE II system was an excellent predictor (area = 0.87, SE = 0.04). Logistic regression analyses suggested that the Charlson index could contribute significant (p = 0.03) prognostic information to that obtained from the components of APACHE II other than Chronic Health, i.e., acute physiological derangement, age, and reason for admission, but the Chronic Health Points component of APACHE II could not so contribute to the rest of APACHE II (p = 0.19). Our conclusion is that use of the detailed information about comorbidity captured by the Charlson index could improve prognostic predictions even for critically ill patients.

APACHE↗

PubMed1996

Randomized prospective comparison of needle colposuspension versus endopelvic fascia plication for potential stress incontinence prophylaxis in women undergoing vaginal reconstruction for stage III or IV pelvic organ prolapse. The Continence Program for Women Research Group.

OBJECTIVE: Severe prolapse may mask potential genuine stress urinary incontinence in women. Some have suggested that a suspending urethropexy be performed in women who have potential genuine stress incontinence demonstrated by barrier reduction of the prolapse preoperatively. Our aim was to compare outcomes after prolapse surgery that included a formal bladder neck suspension with those operations that did not. STUDY DESIGN: This prospective randomized clinical trial assigned 32 women with bladder neck hypermobility and stage III or IV pelvic organ prolapse to receive either a needle colposuspension or bladder neck endopelvic fascia plication as part of the vaginal reconstructive surgery. Twenty-nine subjects underwent detailed clinical, anatomic, urodynamic, and quality-of-life evaluations before and 6 weeks and 6 months after surgery; 23 completed urinary diary and quality-of-life evaluations after a mean of 2.9 years. RESULTS: Needle colposuspension increased short-term complications without providing additional protection from de novo stress incontinence. Barrier testing before surgery predicted urethral sphincteric resistance after surgery; however, such testing neither predicted a patient's function after surgery nor indicated the need for a suspending urethropexy. The combination of a needle colposuspension with a sacrospinous ligament suspension predisposed to the early development of support defects of the upper anterior vaginal segment and to failure of bladder neck support. CONCLUSIONS: Preoperative barrier testing in women with severe prolapse is not useful in identifying individuals who require a suspending urethropexy. Needle colposuspension increases short-term complications, lacks durability, and may predispose to early and severe recurrent anterior prolapse when performed with a sacrospinous ligament vault suspension.

Aged↗

PubMed1995

Short forms to assess life quality and symptom distress for urinary incontinence in women: the Incontinence Impact Questionnaire and the Urogenital Distress Inventory. Continence Program for Women Research Group.

This article describes short form versions of the Incontinence Impact Questionnaire (IIQ) and the Urogenital Distress Inventory (UDI). These instruments assess life impact and symptom distress, respectively, of urinary incontinence and related conditions for women. All subsets regression analysis was used to find item subsets that best approximated scores of the long form versions. The approach succeeded in reducing the 30-item IIQ and the 19-item UDI to 7- and 6-item short forms, respectively. The short form versions may be more useful than the long form versions in many clinical and research applications.

Female↗

PubMed1995

Comparison of "subjective" and "objective" measures of severity of urinary incontinence in women. Program for Women Research Group.

The aims of this study were to compare "subjective" measures of severity of urinary incontinence to similar "objective" measures, establish their statistical correlation, and determine the effect of specific urodynamic diagnosis on such correlations. Baseline data was available from 265 women entered into a clinical trial studying pharmacologic and behavioral interventions for urinary incontinence. The "subjective" measures of incontinence were obtained by patient recall during history taking and included: the number of incontinent episodes in 1 week, the number of perineal pads used during 1 week, and the number of clothing changes required due to wetness. The "objective" measures of severity included: the number of incontinent episodes per week as recorded on a 7-day diary, the number of perineal pads used per week, also recorded on a diary, and the amount of fluid lost during a standardized pad test. Analysis consisted of Pearson correlations and linear regressions to determine equations for the prediction of objective measurement on the basis of the corresponding subjective measure. Significant positive correlations were seen between "subjective" and "objective" measurements for the comparisons of number of weekly incontinent episodes (R = 0.63), and for the weekly number of pads used (R = 0.81). The comparison between the number of clothing changes and the amount of fluid lost during pad testing was also significantly but less strongly correlated (R = 0.24). For the correlations between subjective and objective determinations of urinary incontinent episodes and for those between clothing changes and pad testing, the urodynamic diagnosis had no effect on the correlation coefficients, but did have a statistically significant effect on the intercept.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗

PubMed1995

Correlation of urodynamic measures of urethral resistance with clinical measures of incontinence severity in women with pure genuine stress incontinence. The Continence Program for Women Research Group.

OBJECTIVE: Our aim was to correlate multiple measures of urethral resistance with five clinical measures of incontinence severity in women with pure genuine stress incontinence. STUDY DESIGN: Seventy-five women with pure genuine stress incontinence underwent passive and dynamic urethral pressure profilometry and Valsalva leak point pressure determinations. The standardized and validated measures of incontinence severity included (1) the number of incontinent episodes, (2) the number of continence pads used recorded in a prospective 1-week urinary dairy, (3) grams of fluid loss on a pad quantitation test, and (4) two condition-specific quality-of-life scales, the urogenital distress inventory and the incontinence impact questionnaire. The urodynamic and severity measures were compared with Pearson product-moment correlation analysis. RESULTS: There were no significant correlations between dynamic urethral pressure profile pressure transmission ratios and any measure of incontinence severity. Passive urethral pressure profile variables correlated significantly with incontinence episodes and pad use. Valsalva leak point pressures correlated significantly with pad use and quantitation testing. None of the urodynamic measurements was significantly correlated with either of the quality-of-life scales, but our power to demonstrate a correlation was limited. CONCLUSIONS: Both passive urethral pressure profile measures and Valsalva leak point pressures correlate with some severity measures of genuine stress incontinence. Although inefficient pressure transmission during stress is critical to the pathogenesis of genuine stress incontinence, the severity of the pressure transmission defect is not related to clinical severity. Conversely, impairment of intrinsic urethral resistance is not essential to the pathogenesis of genuine stress incontinence, but the degree of sphincteric impairment is related to severity once the condition exists.

Adult↗

PubMed1995

Valsalva leak point pressures in women with genuine stress incontinence: reproducibility, effect of catheter caliber, and correlations with other measures of urethral resistance. Continence Program for Women Research Group.

OBJECTIVES: The Valsalva leak point pressure has been promoted as an alternative to urethral pressure profilometry as a measure of urethral resistance in women with genuine stress incontinence. Our aims were to evaluate the reproducibility of the Valsalva leak point pressure, to assess the effect of catheter caliber on the Valsalva leak point pressure, and to compare vesical Valsalva leak point pressure to other measures of urethral resistance. STUDY DESIGN: Sixty consecutive women with genuine stress incontinence underwent duplicate Valsalva leak point pressure determinations by use of 8F and 3F vesical and 8F vaginal catheters. Subjects also underwent a standard resting urethral pressure profilometry, cough leak point pressure determinations, and pressure-flow micturition studies. RESULTS: Leakage was demonstrated on both Valsalva maneuvers in approximately 80% of subjects with both catheters. In subjects who leaked with both strains there was an extremely high correlation between the test-retest Valsalva leak point pressure within both catheters. The intercatheter correlation between the 8F and 3F Valsalva leak point pressures was significant but much weaker than the intracatheter correlations; 8F Valsalva leak point pressures were significantly higher than 3F Valsalva leak point pressures, although there were individual exceptions to this observation. Urethral pressure profilometry measures and micturition opening pressures were poorly correlated with Valsalva leak point pressure. Cough and vaginal Valsalva leak point pressures were significantly correlated with vesical Valsalva leak point pressure, but cough leak point pressures were significantly higher and vaginal Valsalva leak point pressures were significantly lower than the vesical Valsalva leak point pressure. CONCLUSIONS: Valsalva leak point pressure is a simple and reproducible technique for evaluating urethral resistance in women with genuine stress incontinence. However, variations in Valsalva leak point pressure measurement must be precisely described, standardized, and validated before a technique can be advocated for clinical use.

Adolescent↗

PubMed1995

Controlling for confounding by indication for treatment. Are administrative data equivalent to clinical data?

There has been controversy about whether confounding by indication for treatment--that is, owing to physicians' conscious efforts to base treatment decisions on patients' pretreatment prognoses--makes nonrandomized, observational comparisons of treatments invalid. Some now believe evidence from studies of practice variation means that physicians' treatment decisions have little relationship to patients' prognostic clinical characteristics. They therefore believe that patients who receive different treatments should vary little in their baseline prognoses, and multivariable statistical methods should easily be able to adjust for any resultant confounding, even when analyses are restricted to administrative rather than clinical data. The objective of this study is to determine whether adjusting for variables found in administrative data sets produces the same results as does adjusting for clinical variables. Data were reanalyzed from a previously enrolled prospective sequential cohort of 227 hospitalized patients with suspected bacteremia who had blood cultures. The treatment under study was aminoglycoside therapy given empirically, that is, before blood culture results were known. The outcome of interest was death during hospitalization. Univariable analyses suggest that empiric aminoglycoside therapy had a positive association with mortality, by univarible logistic regression, odds ratio (OR = 3.1 (95% confidence interval = [1.6, 5.8]). Few administrative variables had univariable associations with aminoglycoside use or death. Multivariable analyses that controlled for them still suggest that aminoglycosides increased mortality; for example, in one model, adjusted OR = 3.2 (1.6, 6.5). Many clinical variables were strongly associated with aminoglycoside use or death. Analyses that controlled for them suggested that empiric aminoglycosides did not increase mortality; for example, in one model, adjusted OR = 1.2 (0.55, 2.7.) Results of adjustment for confounding using administrative data disagreed with the results of adjustment using clinical data. It is concluded that nonrandomized, observational outcome studies that fail to control for prognostic differences between patients receiving different treatments may not always be valid.

APACHE↗

PubMed1994

Postoperative radiotherapy improves survival in squamous cell carcinoma of the hypopharynx.

BACKGROUND: Postoperative radiation is considered to be "standard of care" therapy for advanced, resectable squamous cell carcinoma of the head and neck. This approach has been supported by retrospective data but has not been validated in randomized clinical trials. PATIENTS AND METHODS: The present analysis examined the clinical course of 110 patients with squamous cell cancer of the hypopharynx treated with surgery alone (n = 65) and postoperative radiotherapy alone (n = 45) between 1966 and 1990. Staging of patients was performed using the 1988 American Joint Committee on Cancer criteria. Cox regression analyses identified clinical and pathologic factors that were significant for disease-free and overall survival. Crude and adjusted cancer-specific survival rates were calculated. RESULTS: The postoperative radiotherapy group presented with more advanced disease than the surgery alone group (stage III and IV combined, 96% versus 77%, P = 0.015). Crude 5-year cancer-specific survival probabilities were 43% for the postoperative therapy group and 27% for the surgery alone group (P = NS). Adjusted 5-year survival rates, correcting for differences in significant prognostic variables between groups, were 18% and 48%, respectively, for the surgery and postoperative radiotherapy groups (P = 0.029). CONCLUSIONS: The addition of postoperative radiotherapy was associated with improved disease-free and adjusted overall cancer-specific survival in patients with advanced hypopharyngeal squamous cancer. The potential survival benefit of postoperative radiotherapy should be addressed in a randomized clinical trial.

Carcinoma, Squamous Cell↗

PubMed1994

Estrogen therapy in the management of urinary incontinence in postmenopausal women: a meta-analysis. First report of the Hormones and Urogenital Therapy Committee.

OBJECTIVE: To apply a meta-analysis to available data to evaluate the efficacy of estrogen therapy in the management of postmenopausal women with urinary incontinence. METHODS: The literature review incorporated English language articles based on a search of EXCERPTA MEDICA, BIOSIS, and MEDLINE from January 1969 to June 1992. Criteria included: peer-reviewed original article, confirmed diagnosis of urinary incontinence, an estrogen-treated group, and outcome data on subjective improvement, quantitation of fluid loss, or maximum urethral closure pressure. In addition, the data had to allow comparison between treated and control groups in controlled trials or an estimated change in uncontrolled series. meta-analytic methods were applied only to studies considered to be controlled clinical trials. RESULTS: Of 166 articles reviewed, 143 did not meet the entry criteria; six were considered controlled clinical trials and 17 were uncontrolled series. Meta-analysis found an overall significant effect of estrogen therapy on subjective improvement for all subjects (P < .01) and for subjects with genuine stress incontinence alone (P < .05). The results showed no significant effect on quantity of fluid loss but a significant effect (P < .05) on maximum urethral closure pressure. However, the latter result was influenced by only one study showing a large effect. CONCLUSION: It appears from this analysis that estrogen subjectively improves urinary incontinence in postmenopausal women. However, the studies included nonhomogeneous groups, and the diagnostic criteria, therapeutic interventions, and outcome assessments varied considerably.

Aged↗

PubMed1993

Computer-assisted instruction in probabilistic reasoning during the inpatient medicine clerkship.

The acceptability and utility of computer-assisted instruction in probabilistic reasoning was assessed for medicine clerkship students. After a pretest, the experimental (n = 40), but not the control students (n = 39), completed a program that we designed. The program contained the test and its answers. After program exposure, experimental students rated their knowledge of the program's content significantly higher (p = 10(-4)) than control students. On the identical posttest, experimental students also scored significantly higher than control students (p = 10(-4)) and improved their scores significantly more (p = 10(-3)). They rated ease-of-use items significantly higher than content-relevance items (p = 10(-4)). We conclude that computer-assisted instruction in probabilistic reasoning is acceptable to clerkship students, and that it may improve their knowledge and skills in this area. However, students may rate the vehicle of this instruction more highly than its content.

Clinical Clerkship↗

PubMed1992

Stage III breast cancer: is neoadjuvant chemotherapy always necessary?

Optimal management of locally advanced breast cancer is controversial. Claims of superiority for neoadjuvant systemic therapy are based on comparisons with outdated historical control groups who received no chemotherapy. Between 1978 and 1987, 118 patients with locally advanced breast cancer underwent treatment and follow-up at the Medical College of Virginia. Median follow-up was 44 months (range 3-119 months). Actuarial 5-year survival for the entire group was 54%. This compares favorably with recent series using neoadjuvant chemotherapy in which 5-year survival rates of 40-65% have been reported. Primary tumor size larger than 9 cm, metastases to more than 50% of regional lymph nodes, and the presence of inflammatory disease were significant prognostic indicators. This series represents a contemporary control group of patients with locally advanced breast cancer in whom conventionally accepted guidelines for local and postoperative systemic adjuvant therapy were used. Until the optimal sequence of therapy is determined by prospective randomized trials, series such as this may serve as more appropriate controls to which the results of new therapies could be compared.

Adenocarcinoma↗

PubMed1992

Obesity and lower urinary tract function in women: effect of surgically induced weight loss.

OBJECTIVE: The subjective and objective effects of massive weight loss on lower urinary tract function in morbidly obese women were examined. STUDY DESIGN: Thirteen subjects underwent a comprehensive evaluation of lower urinary tract function before and 1 year after surgically induced weight loss. RESULTS: We demonstrated significant improvements in lower urinary tract function after weight loss. Of 12 subjects who complained of incontinence before surgery only three complained of incontinence (p = 0.004) and only one requested treatment after weight loss. Objective and subjective resolution of both stress and urge incontinence was documented. Statistically significant changes were seen in measures of vesical pressure, the magnitude of bladder pressure increases with coughing, bladder-to-urethra pressure transmission with cough, urethral axial mobility, number of incontinence episodes, and the need to use absorptive pads. CONCLUSION: Weight reduction is desirable for obese women complaining of urinary incontinence and may obviate the need for further incontinence therapy.

Adult↗

PubMed1992

Cigarette smoking and urinary incontinence in women.

OBJECTIVE: The goal of this case control study was to evaluate the relationship between smoking and female urinary incontinence. STUDY DESIGN: The study included 606 women whose smoking histories were known; 322 were incontinent and 284 were continent. The condition(s) causing each subject's incontinence was determined by urodynamic testing; 40% of the continent subjects had the same testing. RESULTS: There were highly significant overall differences (p = 0.000009) in the distribution of current, former, and never smokers between incontinent (35%, 16%, 49%) and continent (24%, 8%, 68%) groups. The odds ratio for genuine stress incontinence was 2.20 for former (95% confidence interval 1.18 to 4.11) and 2.48 for current smokers (95% confidence interval 1.60 to 3.84); for motor incontinence it was 2.92 for former (95% confidence interval 1.58 to 5.39) and 1.89 (95% confidence interval 1.19 to 3.02) for current smokers. Increasing daily and lifetime cigarette consumption was associated with an increasing odds ratio for genuine stress incontinence but not for motor incontinence. The increased risk for incontinence was not due to differences in age, parity, weight, or hypoestrogenic status. CONCLUSION: The data establish a strong statistical relationship between current and former cigarette smoking and both stress and motor urinary incontinence in women.

Adolescent↗

PubMed1991

Altered membrane anisotropy gradients of plasma membranes of living peripheral blood leukocytes in aging and Alzheimer's disease.

Several reports have suggested that membrane rigidity, a term that refers to the relative motion of membrane constituents, is decreased in Alzheimer's Disease. Accordingly, a series of fluorescent membrane probes was used to evaluate the rigidity from the surface to the center of the outer hemi-leaflet of the plasma membrane of living neutrophils, monocytes and lymphocytes. Anisotropy, a parameter which increases with increasing membrane rigidity, was calculated from flow cytometric measurements of vertically and horizontally polarized components of the fluorescence emission of the probes. These preliminary experiments suggest that whereas membrane rigidity in certain regions of the plasma membrane of peripheral blood leukocytes is increased as expected in elderly controls, it is decreased in Alzheimer's disease.

Aging↗