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Biomedical subjects

S Azen

Publications and source records attributed to S Azen.

14 recordsLinked to original sources

Ethnicity and attitudes toward patient autonomy.

OBJECTIVE: To study differences in the attitudes of elderly subjects from different ethnic groups toward disclosure of the diagnosis and prognosis of a terminal illness and toward end-of-life decision making. DESIGN: Survey. SETTING: Thirty-one senior citizen centers within Los Angeles County, California. RESPONDENTS: A stratified quota sample of 200 subjects aged 65 years and older self-identified as being from each of four ethnic groups: European American, African American, Korean American, or Mexican American (N = 800). MAIN OUTCOME MEASURES AND RESULTS: Korean Americans (47%) and Mexican Americans (65%) were significantly less likely than European Americans (87%) and African Americans (88%) to believe that a patient should be told the diagnosis of metastatic cancer. Korean Americans (35%) and Mexican Americans (48%) were less likely than African Americans (63%) and European Americans (69%) to believe that a patient should be told of a terminal prognosis and less likely to believe that the patient should make decisions about the use of life-supporting technology (28% and 41% vs 60% and 65%). Instead, Korean Americans and Mexican Americans tended to believe that the family should make decisions about the use of life support. On stepwise multiple logistic regression, ethnicity was the primary factor related to attitudes toward truth telling and patient decision making. CONCLUSIONS: Korean-American and Mexican-American subjects were more likely to hold a family-centered model of medical decision making rather than the patient autonomy model favored by most of the African-American and European-American subjects. This finding suggests that physicians should ask their patients if they wish to receive information and make decisions or if they prefer that their families handle such matters.

Black or African American

Time parameters for glaucoma procedures.

Changes in physician reimbursement and the practice environment have emphasized the importance of determining physician time for procedures and services. Forty-five percent of the members of the American Glaucoma Society responded to a mail survey of estimates of the length of time and number of visits for the preoperative, operative, and 90-day postoperative care for six common glaucoma procedures. Results suggest a significant underestimation of time for trabeculectomies exists in the original and new resource-based relative value scale work values. Further, 47% to 53% of surgeons hospitalize patients on at least the first postoperative day. There were no apparent time efficiencies between "high-" and "low-volume" respondents. Thus, careful attention should be paid to the accuracy of certain time estimates and the resulting work values in the resource-based relative value scale. Additional work in this and other areas may prove illuminating.

Glaucoma

Generalization of normal discriminant analysis using Fourier series density estimators. Transfusion Safety Study Group.

In this paper we examine the efficiency of a generalization of the traditional normal linear (LDA) or quadratic (QDA) discriminant analysis. This procedure (the generalized discriminant analysis, GDA) replaces each normal density used in the traditional classification rule by a Fourier series density estimator which 'adjusts' the normal density if the data deviate markedly from normality (for example, heavily skewed or multimodal). We derive the GDA in both the univariate and multivariate situations. In a simulation study for the univariate situation, we evaluate the relative efficiency of the GDA. In addition, we demonstrate the performance of the GDA through a series of multivariate applications. We conclude that if the distributions of the data do not deviate markedly from normality, the GDA is as efficient as the LDA or QDA. On the other hand, if either of the distributions deviates from normality, then the GDA, which performs as a semiparametric discriminant procedure, is more efficient than the LDA or QDA.

Antigens, Differentiation

The effect of therapeutic treatment crossovers on the power of clinical trials. The Silicone Study Group.

The Silicone Study is a randomized clinical trial comparing two surgical methods for reattaching the retina when detachment is associated with proliferative vitreoretinopathy. If the retina redetaches subsequently, the patient will usually undergo additional surgery using the assigned treatment. In a limited number of cases the patient may be switched to the alternative treatment, if a "therapeutic crossover" is endorsed by an independent committee of ophthalmologists. A successful outcome is continued anatomic attachment of the retina and an adequate visual result 6 months after the final surgery. The therapeutic treatment crossovers affect the power of the trial to detect a difference between the two treatments. A simulation study shows that the loss in power depends on the magnitude and degree of bias in the probability of being switched from one treatment to the other. Unlike the usual case of lack of compliance, complete information about treatment history may allow statistical adjustment for the crossover. The outcome may be modeled using a multinomial distribution. Much of the power lost due to switching may be recouped under some strong assumptions.

Computer Simulation

Primary hypertension: left ventricular mass and function, sympathetic nervous system activity, and therapy.

Left ventricular (LV) mass is a predictor of morbidity in patients with hypertension. To elucidate the mechanisms of left ventricular hypertrophy (LVH) in primary hypertension, we examined the relationships of LV mass, arterial blood pressure, and plasma norepinephrine--as a marker of sympathetic nervous system tone--in three populations of patients with mild or moderate hypertension. We found linking of neural tone with (a) arterial blood pressure in mild and moderate hypertension, (b) LV mass in moderate hypertension, and (c) diastolic function in mild hypertension, suggesting that neural tone is a factor in both the pathogenesis and the sequelae of hypertension. Additionally, elevated norepinephrine level may reflect subtle loss of diastolic function before hypertrophy is manifest. Both nondrug and drug therapy may regress LV mass after blood pressure reduction with disparate effects on neural tone.

Adult

Immunopathology of acute experimental histoplasmic choroiditis in the primate.

The immunopathologic features of experimental acute histoplasmic choroiditis were studied in the nonhuman primate. Using an indirect immunoperoxidase technique, a panel of hybridoma-derived anti-human monoclonal antibodies, recognizing distinct lymphoid cell and macrophage surface antigens, have been adapted for use in the primate system. Twenty-two individual foci of histoplasmic choroiditis from five eyes were studied at time periods from 20 to 60 days post intracarotid injection of yeast phase Histoplasma capsulatum. A mononuclear and granulocytic cell infiltration was seen in all lesions. The predominant cell type was the CAPPEL+ T lymphocyte (suppressor/cytotoxic subset). Other cell types found in smaller numbers were OKT4+ T cells (helper/inducer subset), OK7+ (peripheral B lymphocytes), IgD+ (mantle B cells) and OKM1+ cells (macrophages and polymorphonuclear leukocytes). Herein, we present immunopathologic data on the acute phase of experimental ocular histoplasmosis.

Acute Disease

Neurohumoral mechanisms and left ventricular hypertrophy: effects of hygienic therapy.

To determine the effects of hygienic (non-drug) therapy on blood pressure (BP) control and its relationship to sympathetic tone and left ventricular mass (LVM) in primary hypertension, plasma norepinephrine (NE) and renin activity (PRA), LVM, and nutritional and behavioral status were assessed in 76 borderline to mild hypertensives. Pretherapy plasma NE was related to diastolic blood pressure (DBP) and PRA (r = 0.24, P less than .05 and r = 0.37, P less than .01, respectively). Plasma NE of high renin patients (221 +/- 52) (mean +/- SD) was greater than that of normal renin patients (159 +/- 61, ng/l, P less than .01). LVM was related to systolic blood pressure (SBP) (P less than .001), DBP (P less than .01) and urinary sodium (P less than .05), and inversely related to PRA (P less than .01). Septal wall thickness was related to hostility (r = 0.42, P less than .05). After seven weeks of hygienic therapy, DBP was reduced by 6 mmHg (P less than .01). The change in SBP was related to baseline plasma NE (P less than .05) and inversely related to LVM (P less than .05). These results suggest that raised sympathetic tone may be a pathogenic factor in primary hypertension and that hygienic therapy lowers BP more effectively in patients with raised sympathetic tone and low LVM.

Adult

Cardiac output by thermodilution technique. Effect of injectate's volume and temperature on accuracy and reproducibility in the critically Ill patient.

We compared determinations of cardiac output using various combinations of injectate volumes and temperatures to results obtained with 10 ml of iced (0 degrees C) injectate (standard technique) in 33 critically ill patients. The use of a 10-ml injectate at room temperature resulted in comparable reproducibility (12.7 vs 10.8 percent; not significant) and a small and nonsignificant error (-0.013 +/- 0.543 L/min). Five milliliters at room temperature resulted in markedly decreased reproducibility (17.9 vs 8.9 percent; p less than 0.05); however, the error associated with the technique was still not significant (0.136 +/- 0.829 L/min). When a 5-ml injectate at 0 degrees C was used, a reproducibility comparable to that of 10 ml at 0 degrees C was obtained (12.3 vs 7.5 percent; not significant). The results underestimated values obtained with 10 ml at 0 degrees C (-0.360 +/- 0.857 L/minute); however, the difference did not reach statistical significance. The use of 3 ml at 0 degrees C was associated with a substantial increase in variability, with a coefficient of variation of 32.0 percent (10.4 percent for 10 ml of iced injectate; p less than 0.01); however, the differences between the average value of cardiac output obtained with this technique and the standard technique were only minimal (error, -0.063 +/- 0.455; not significant). We reached the following conclusions: (1) the use of 10 ml at room temperature and 5 ml at 0 degrees C as the indicator for thermodilution determinations of cardiac output results in small and insignificant differences in reproducibility and accuracy from the standard technique; (2) five milliliters at room temperature and 3 ml at 0 degrees C are associated with markedly decreased reproducibility; however, the error in values for cardiac output obtained with these techniques is not statistically significant; and (3) the ability to use injectate at room temperature and in small volume should substantially simplify the technique, lowering its cost, and should prevent volume overloading.

Adult

Complement components in kidney allograft recipients: relationship to cytomegalovirus infection.

Serum complement profiles of 19 renal transplant recipients were studied serially before and after renal transplantation to determine if there is any relationship between cytomegalovirus (CMV) infection and alteration in the serum complement (C) levels. Most patients had low serum C3 and C4 levels before transplantation, but afterwards these levels increased in some patients. Clq was elevated before and after transplantation. Factor B was low before transplantation, but after surgery, its level approached normal in patients without cytomegalovirus viremia, whereas in those with viremia, Factor B level became even more depressed. Circulating Factor B fragments were found in the sera of five out of seven patients with active cytomegalovirus infection, which suggests activation of the alternative pathway possibly related to active CMV infection.

Adult

Infants with birth weight under 1500 g: physical, neurological, and developmental outcome.

One hundred and seventy-eight infants with birth weights less than or equal to 1500 g born in 1973-1975 were followed for a period of 1-3 years, and the physical, neurological, and developmental outcome evaluated. Although there was a high incidence of maternal problems, these did not correlate with outcome. Asphyxia at birth followed by neonatal complications leading to ventilatory assistance was significantly correlated with poor outcome. Over 50% of infants less than 100 g birth weight required assisted ventilation, but the outcome in small ventilated infants was comparable to that of ventilated infants of 1001-1500 g birth weight. Infants with neurological abnormality showed a high incidence of associated abnormalities in growth, vision, hearing, and development. Spastic quadriplegia emerged as the most common neurological diagnosis. Despite the many perinatal problems, 82% of the group were normal neurologically and 66% developmentally. The overall outcome was generally favorable in these infants even for those requiring ventilation.

Child Development

Association of immune responsiveness to cytomegalovirus infection with survival of renal allografts.

The association of immune responsiveness to cytomegalovirus infection was studied in relation to survival of renal allografts. The presence of anti-cytomegalovirus antibody in the pre-transplant patient was not associated with any detrimental effect on the graft survival. The presence or absence of cytomegalovirus antigen or of cytomegalovirus antibody, or later development of cytomegalovirus antibody, in no way affected the graft survival. The same conclusion was reached in cases when kidneys from male donors were used in cytomegalovirus antibody-postive patients.

Adult

Early predictors of incomplete recovery in children with Guillain-Barr'e polyneuritis.

Case histories of 47 children with strict criteria for Landry-Guillain-Barré-Strohl polyneuritis admitted to a rehabilitation facility from late 1959 through 1972 were analyzed retrospectively. The children were followed to full recovery (good to normal strength in all muscle groups) or for three years without full recovery. The data were then compared statistically for possible predictive indicators of recovery or lack of recovery within three years. The most significant early predictor of incomplete recovery was the time interval between the greatest weakness and beginning improvement; a period longer than 18 days of plateau before gains are evident is indicative of incomplete recovery within limits of 99% confidence.

Cerebrospinal Fluid Proteins

Succinylcholine as a predictor in strabismus surgery.

Succinylcholine was injected intraoperatively in 20 patients with congenital esotropia, before and after the surgical procedure. Regression analysis was performed to investigate the relationship between the awake pre- and postoperative alignment and the drug-induced ocular positions, under anesthesia. The postoperative succinylcholine-induced ocular position was found to be a highly significant predictor of the one week postoperative alignment (r = 0.98, p less than 0.0001). Further investigation may lead to an ability to predict the postoperative alignment intraoperatively.

Anesthesia, General