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Objective: Existing scales of functional performance are either insufficiently sensitive or omit some important daily life tasks. This paper demonstrates that a new scale of self-perceived disablement in the vestibularly impaired population-the Vestibular Disorders Activities of Daily Living Scale (VADL)-differentiates between disabled and healthy persons and evaluates the associations of this assessment with other measures of vestibular disorders.Study Design: Prospective.Methods: Subjects were 1) asymptomatic, healthy adults, 2) patients with benign paroxysmal positional vertigo, 3) patients with chronic vestibulopathy excluding Meniere's disease, postsurgical vertigo, and postconcussion vertigo, and 4) family members. Patient were assessed on the VADL, the Dizziness Handicap Inventory, level of vertigo, and computerized dynamic posturography. Healthy subjects and family members completed the VADL.Results: The VADL differentiates healthy persons from patients but does not differentiate between patient groups. Patients perceived themselves as more independent than their spouses perceived them to be. Scores are weakly correlated with vertigo frequency and posturography scores for conditions with unreliable kinesthesia and absent or unreliable vision. The VADL is more responsive to higher levels of impairment than the Dizziness Handicap Inventory.Conclusions: This well-normed, self-administered scale of self-perceived disablement is useful for evaluating the functional status of patients with peripheral vestibular disorders. Perceptions of patients and significant others vary, but scores are moderately correlated with some standard measures of vestibular function. As it assesses a different domain of function than do standard diagnostic tests, the VADL will augment these tests during initial evaluation and may be useful for assessing posttreatment change. [ABSTRACT FROM AUTHOR]

Background: Adenosine perfusion scintigraphy is a powerful technique for diagnosing coronary artery disease and risk stratifying patients with recent myocardial infarction.Methods and Results: We investigated the use of adenosine 201Tl tomography to risk stratify 106 patients undergoing vascular arterial reconstruction consisting of lower limb arterial grafting in 44, aortic aneurysmectomy in 36, and carotid endarterectomy in 26 patients. Abnormal tomograms occurred in 57 patients (54%), 47 (82%) of whom had reversible perfusion defects. There were three postoperative deaths, all in the group that underwent aortic aneurysmectomy. Another patient with an aortic aneurysm had unstable angina and one patient who underwent lower limb arterial surgery had pulmonary edema after surgery. No patient without transient defects had an event (negative predictive value 100%). Cardiac events occurred only in patients with transient perfusion defects. However, only 5 of 47 such patients had events (positive predictive value 11%). The perfusion defect size (23% +/- 14% vs 8.9% +/- 135; p = 0.034) and the ischemic fraction (20% +/- 16% vs 5.6% +/- 8.9%; p = 0.009) were 2.5- and 3.5-fold larger, respectively, in patients with than in those without events. A history of diabetes mellitus or previous infarction did not enhance the predictive value of the test.Conclusion: Thus absence of reversible hypoperfusion during adenosine scintigraphy ensures virtual absence of postoperative cardiac events. Patients undergoing aortic aneurysmectomy may be targeted preferentially for risk-stratification strategies in the future. [ABSTRACT FROM AUTHOR]

This study investigated whether symptoms of depression and anxiety were related to the development of elevated blood pressure in initially normotensive adults. The study's hypothesis was addressed with an existing set of prospective data gathered from an age-, sex-, and weight-stratified sample of 508 adults. Four years of follow-up data were analyzed both with logistic analysis, which used hypertension (blood pressure > or =140 mm Hg systolic or 90 mm Hg diastolic) as the dependent variable, and with multiple regression analysis, which used change in blood pressure as the dependent variable. Five physical risk factors for hypertension (age, sex, baseline body mass index, family history of hypertension, and baseline blood pressure levels) were controlled for in the regression analyses. Use of antidepressant/antianxiety and antihypertensive medications were controlled for in the study. Of the 433 normotensive participants who were eligible for our study, 15% had missing data in the logistic regression analysis focusing on depression (n = 371); similarly, 15% of the eligible sample had missing data in the logistic regression using anxiety as the psychological variable of interest (n = 370). Both logistic regression analyses showed no significant relationship for either depression or anxiety in the development of hypertension. The multiple regression analyses (n = 369 for the depression analysis; n = 361 for the anxiety analysis) similarly showed no relationship between either depression or anxiety in changes in blood pressure during the 4-year follow-up. Thus, our results do not support the role of depressive or anxiety symptoms in the development of hypertension in our sample of initially normotensive adults.

Background: Existing scales of self-perceived disablement in patients with vestibular impairment either are too broad to detect the subtle deficits in this population or omit some important daily life tasks., Objectives: To develop a scale to assess self-perceived disablement in patients with vestibular impairment and to describe the development and initial testing of this new assessment tool., Design: A list of items was developed, sent to a panel of expert therapists for review, and then revised to yield the preliminary 31-item, 10-point scale that was administered to subjects. The scale was revised again, yielding the final 28-item scale, which was administered to a new group of subjects., Setting: Data were collected from patients in an outpatient clinic of a tertiary care center., Participants: Patients diagnosed as having benign paroxysmal positional vertigo and patients diagnosed as having chronic vestibulopathy, excluding Ménière disease, postsurgical vertigo, and postconcussion vertigo., Results: The final scale has 3 subscales: functional, ambulation, and instrumental. It has good face validity, high internal consistency (alpha> or =.90), and high test-retest reliability (r(c)> or =0.87). Scale ratings ranged from 1 (independent) to 10 (ceasing to participate in the activity), but median scores for most subjects were 4 or less. From 41% (39/94) to 44% (41/94) of subjects considered themselves to be independent on those tasks., Conclusions: This scale has good face validity, high internal consistency, and high test-retest reliability. It may be useful for evaluating functional limitation and perceived handicap or disability before and after intervention and for helping patients become more realistic in understanding their own capabilities.

Long-term changes in the parameters of the vestibulo-ocular reflex (VOR) were evaluated using recently developed multilevel statistical modelling techniques in a group of patients who had undergone ablative inner ear procedures. Data from 84 patients were available for study. The most dramatic recovery in the VOR occurred during the first 60 postoperative days, however, slow changes continued, levelling off at about 120 days. While frequency was a highly significant predictor of outcomes in all parameters, age showed significant predictive value only to phase measures (p = 0.006) and gender had no effect. Sum gain at the lowest frequency tested remained below the 5th percentile and at the higher frequencies remained below the 50th percentile for normal subjects. Phase decreased exponentially, but remained above the 95th percentile for normal subjects, except at the highest frequency where it remained above the 50th percentile. DC bias decreased exponentially, dropping to the 50th percentile by day 146. Asymmetry stayed between the 50th and 95th percentile, except at the highest frequency, where it was at the 50th percentile by day 125.

Objective: In treatment of binge eating, measures of self-concept, eating self-efficacy, and social support were examined at 0, 6, and 18 months to determine if improvements in these variables were associated with reductions in binge eating severity., Method: Obese adult females (N = 125) were treated for 6 months, with 12 months of maintenance meetings. The Binge Eating Scale (BES), Tennessee Self-Concept Scale (TSC), Dieter's Inventory of Eating Temptations (DIET), and a social support measure (SocSup) were used., Results: Over the first 6 months, improvements in BES were associated with improvements in the TSC and DIET. Over 18 months, improvements in BES were associated with improvements in the TSC, DIET, and SocSup., Discussion: Therapy for binge eating should result in improvement in self-concept and eating self-efficacy, as well as reductions in binge eating. This study showed that self-concept and eating self-efficacy were associated with improvement in binge eating severity. The association with social support did not appear until long-term follow-up. Improvement in self-concept and eating self-efficacy may be processes leading to clinical improvement in this eating disorder, or they may result from changes in binge eating., (Copyright 1999 by John Wiley & Sons, Inc.)

Background: Patients with hypertriglyceridemia (HTG) are generally advised to avoid alcohol, even though moderate alcohol consumption is cardioprotective. Alcohol increases plasma triglyceride concentration transiently in normolipidemic subjects, but whether alcohol consumption per se increases triglyceride concentrations in patients with HTG is unclear., Objective: To assess whether baseline fasting triglyceride concentration determines plasma triglyceride concentration after acute oral alcohol intake., Methods: Twelve persons with fasting triglyceride concentrations of 2.3 to 8.5 mmol/L (200-750 mg/dL) and 12 persons as a non-HTG group were enrolled. Obesity, current smoking, and history of hypertension, diabetes, or excessive alcohol use were exclusionary. Fasted subjects consumed 38 mL of ethanol in water (equivalent, 2 alcoholic drinks); blood samples were collected at baseline and at intervals thereafter for 10 hours. No less than 1 week later, the subjects consumed water alone in a control test., Results: Mean triglyceride values were 4.04+/-0.41 mmol/L (358+/-36.9 mg/dL) and 1.00+/-0.11 mmol/L (89+/-10.2 mg/dL) for the HTG and non-HTG groups, respectively. Despite similar changes with alcohol feeding in plasma ethanol, nonesterified fatty acid, and acetate concentrations, the groups differed in triglyceride response. At 6 hours (peak) compared with baseline, triglyceride concentration increased only 3% in the HTG group but 53% in the non-HTG group. The former change was not significantly different from the effect with water alone (-9.2% from baseline; P = .43), whereas the latter was (-8.0%; P = .003)., Conclusions: Acute alcohol intake alone is not an important determinant of plasma triglyceride concentration in individuals with HTG. Other factors, such as the contemporaneous consumption of fat and alcohol, known to increase triglyceride concentrations synergistically in non-HTG individuals, may be more important.

Study Objectives: To perform a population-based study addressing the demography, epidemiology, management, and outcome of out-of-hospital pediatric cardiopulmonary arrest (PCPA)., Methods: Prospective, population-based study of all children (17 years of age or younger) in a large urban municipality who were treated by EMS personnel for apneic, pulseless conditions. Data were collected prospectively for 3(1/2) years using a comprehensive data collection tool and on-line computerized database. Each child received standard pediatric advanced cardiac life support., Results: During the 3(1/2)-year period, 300 children presented with PCPA (annual incidence of 19. 7/100,000 at risk). Of these, 60% (n=181) were male (P =.0003), and 54% (n=161) were patients 12 months of age or younger (152,500 at risk). Compared with the population at risk (32% black patients, 36% Hispanic patients, 26% white patients), a disproportionate number of arrests occurred in black children (51.6% versus 26.6% in Hispanics, and 17% in white children; P <.0001). Over 60% of all cases (n=181) occurred in the home with family members present, and yet those family members initiated basic CPR in only 31 (17%) of such cases. Only 33 (11%) of the total 300 PCPA cases had a return of spontaneous circulation, and 5 of the 6 discharged survivors had significant neurologic sequelae. Only 1 factor, endotracheal intubation, was correlated positively with return of spontaneous circulation (P =.032)., Conclusion: This population-based study underscores the need to investigate new therapeutic interventions for PCPA, as well as innovative strategies for improving the frequency of basic CPR for children.

Objective: To evaluate the psychometric properties, including the factorial and predictive validity, of the Diet Readiness Test (DRT) in a clinical population., Method: The DRT was administered to 132 women who participated in an obesity and binge eating treatment study., Results: The DRT demonstrated adequate internal consistency. The DRT's proposed factor structure was not supported. Neither the DRT subscales nor the derived factors predicted changes in weight, binge eating, or exercise., Discussion: The DRT did not demonstrate factorial or predictive validity in this study. Based on the DRT's cutoff criteria, 100% of the sample was considered not ready to begin a weight loss program, suggesting that the DRT may have limited utility with clinical populations.

Hypertriglyceridemia may contribute to the development of atherosclerosis by increasing expression of cell adhesion molecules (CAMs). Although the cellular expression of CAMs is difficult to assess clinically, soluble forms of CAMs (sCAMs) are present in the circulation and may serve as markers for CAMs. In this study, we examined the association between sCAMs and other risk factors occurring with hypertriglyceridemia, the effect of triglyceride reduction on sCAM levels, and the role of soluble vascular cell adhesion molecule-1 (sVCAM-1) in monocyte adhesion in vitro. Compared with normal control subjects (n=20), patients with hypertriglyceridemia and low HDL (n=39) had significantly increased levels of soluble intercellular adhesion molecule-1 (sICAM-1) (316+/-28.8 versus 225+/-16.6 ng/mL), sVCAM-1 (743+/-52.2 versus 522+/-43.6 ng/mL), and soluble E-selectin (83+/-5.9 versus 49+/-3.6 ng/mL). ANCOVA showed that the higher sCAM levels in patients occurred independently of diabetes mellitus and other risk factors. In 27 patients who received purified n-3 fatty acid (Omacor) 4 g/d for > or =7 months, triglyceride level was reduced by 47+/-4.6%, sICAM-1 level was reduced by 9+/-3.4% (P=.02), and soluble E-selectin level was reduced by 16+/-3.2% (P<.0001), with the greatest reduction in diabetic patients. These results support previous in vitro data showing that disorders in triglyceride and HDL metabolism influence CAM expression and treatment with fish oils may alter vascular cell activation. In a parallel-plate flow chamber, recombinant sVCAM-1 at the concentration seen in patients significantly inhibited adhesion of monocytes to interleukin-1-stimulated cultured endothelial cells under conditions of flow by 27.5+/-7.2%. Thus, elevated sCAMs may negatively regulate monocyte adhesion.

This study evaluated the effectiveness of nondieting versus dieting treatments for overweight, binge-eating women. Participants (N = 219) were randomly assigned to 1 of 3 groups: diet treatment (DT), nondiet treatment (NDT), or wait-list control (WLC). DT received a balanced-deficit diet reinforced with behavioral strategies. NDT received therapy designed to help participants break out of their dieting cycles. Treatment in both conditions was administered in weekly groups for 6 months, followed by 26 biweekly maintenance meetings, for a total of 18 months of contact. At 6 months posttreatment, DT lost 0.6 kg while NDT gained 1.3 kg. Both treatment groups reduced their Binge Eating Scale scores significantly more than WLC. At 18-month follow-up, both treatment groups experienced weight gain but maintained similar reductions in binge eating. Results indicate that neither intervention was successful in producing short- or long-term weight loss. Therapist biases, which may have affected treatment integrity, and other methodological issues are discussed in relation to the small weight losses achieved.

Objective: To compare rates of adherence to low-fat diets using food-record rating and fat-gram counting, to evaluate dietary adherence using the fat-gram counting method, and to assess correlations between food-record rating and fat-gram counting., Design: A diet monitoring and observation study was conducted to compare the effectiveness of food-record rating and fat-gram counting to evaluate dietary adherence. Subjects were randomly assigned to the food-record rating group of the fat-gram counting group. Each participant was asked to complete four 3-day food records. Food records were evaluated by food-record rating for one group and by fat-gram counting for the other. Each record was then scored using the alternate system. For a subset, manually calculated fat-gram values were compared for accuracy with values from the Nutrient Data Systems database., Statistical Analyses Performed: Mantel-Haenszel chi 2, regression, and K analyses were used to evaluate adherence rates and within-subject agreement between fat-gram counting and food-record rating., Subjects/setting: Seventy-eight participants were recruited from a lipid-lowering research trial conducted in Houston, Tex., Results: Strong correlations were found between fat-gram values calculated manually and those calculated using the Nutrient Data Systems. No significant differences in adherence rates were found between the food-record rating and fat-gram counting groups., Conclusions: Fat-gram counting is at least as effective as food-record rating in monitoring dietary fat content. Dietitians can use it as an alternative dietary fat-monitoring procedure for clinical practice and research.

Background: Although myocardial perfusion scintigraphy is of proven value in the risk stratification of patients with a recent myocardial infarction who receive conventional therapy, its value in patients undergoing thrombolytic therapy remains controversial., Methods and Results: Seventy-one patients who received thrombolytic therapy for acute myocardial infarction had exercise 201Tl tomography and coronary angiography before hospital discharge. Eleven (15%) of 71 patients had ischemic ST-segment depression during exercise, whereas 27 patients (38%) had scintigraphic ischemia. Twenty-five (37%) of 68 patients had a cardiac event consisting of either death (n = 2), recurrent myocardial infarction (n = 5), congestive heart failure (n = 7), or unstable angina (n = 11) during a follow-up of 26 +/- 18 months. Univariate predictors of cardiac events were as follows: Killip class (P = .04); left ventricular ejection fraction (P < .0005); total (P = .002) and ischemic (P < .0005) perfusion defect size; percent thallium lung uptake (P = .001); presence of infarct-zone redistribution (P = .02); and multivessel coronary artery disease (P = .01). By multivariate analysis, the significant joint predictors of risk were ejection fraction (P < .0005) and ischemic perfusion defect size (P = .005). The combination of ejection fraction and thallium tomography added significant incremental prognostic information to the clinical data, whereas angiography did not further improve a model that included clinical, ejection fraction, and tomographic variables., Conclusions: Quantitative exercise 201Tl tomography provides important incremental, long-term prognostic information in patients receiving thrombolytic therapy for acute myocardial infarction.

Background: Patients with hematologic malignancy who develop respiratory failure generally have a very poor prognosis. A few such patients, however, enjoy long-term survival. The objective of this study was to identify clinical characteristics of patients with hematologic malignancy and respiratory failure that are predictive of outcome., Methods: We performed a retrospective chart review of all patients who required mechanical ventilation for acute respiratory failure while on the leukemia or bone marrow transplantation units at the Johns Hopkins Oncology Center between January 1985 and October 1991 (n = 157)., Results: Overall hospital mortality was 83%. Major organ system dysfunction, as measured by the acute physiology score (APS) of the APACHE III prognostic system, was significantly (P < 0.05) related to hospital mortality. Three disease-specific clinical characteristics were predictive of mortality: 1) stage beyond first complete remission, 2) duration of neutropenia greater than 30 days, and 3) treatment with bone marrow transplantation, especially if HLA-mismatched. None of the 15 (10%) patients with neutropenia greater than 30 days or the four patients who underwent HLA-mismatched transplantation survived to discharge. Age was also a significant predictor of hospital mortality., Conclusions: Overall outcome of patients with hematologic malignancy and acute respiratory failure is poor. A larger prospective study will be required to confirm the relative value of disease-specific variables identified in this study when combined with established predictive variables. In the future, it may be possible to develop a predictive instrument that is specifically tailored for patients with hematologic malignancy who develop respiratory failure.

Objective: Our purpose was to study the safety and efficacy of external cephalic version before term (37 weeks' gestation)., Study Design: We retrospectively reviewed 114 pregnancies in 110 women at 30 to 41 weeks' gestation who had a total of 133 attempts at external cephalic version., Results: Seventy-nine percent of the versions performed before the thirty-seventh week and 53% performed during or after the thirty-seventh week were successful. After adjustment parity and body mass index, a version performed before the thirty-seventh week was 27 times more likely to be successful than if performed during or after the thirty-seventh week. Ninety-nine percent of the successful versions were delivered with a vertex presentation, and of these only 16% required cesarean delivery., Conclusion: External cephalic version is safe and successful if performed before 37 weeks' gestation, hence substantially reducing the rate of cesarean section among nonvertex presentations and reducing the risks associated with breech delivery.

A retrospective study was performed to evaluate the ability to predict sperm-surface antisperm antibodies (ASA) in patients with primary infertility on the basis of semen analysis. In particular, the ability to predict ASA status on the basis of impaired sperm motility was assessed. The clinical and seminal characteristics of 70 consecutive ASA-positive infertility patients detected by routine screening were reviewed. Similar analysis was performed on 128 consecutive patients with infertility who were found on routine screening to be ASA-negative. The association between the presence of ASA and sperm motility, concentration, and clumping was examined using multivariate analysis. Two variables were found to have a significant joint association with the presence of ASAs. Patients with sperm concentrations of > 20 million/ml were significantly more likely to be ASA-positive (P = 0.002). Second, after adjustment for sperm concentration, patients with lower motilities were significantly more likely to be ASA-positive (P = 0.016). Although impaired motility was seen significantly more often in ASA-positive patients, this seminal defect alone should not be used for predictive screening, since 39% of ASA-positive patients had sperm motilities of > 60%. Furthermore, when a normal sperm concentration (> 20 million/ml) was combined with impaired sperm motility (< 60%) as an indication for ASA testing in this population, the result was a sensitivity of only 43%, a specificity of 77%, and positive and negative predictive values of 50% and 77%, respectively. Despite the association between normal sperm concentrations and impaired motility, it appears that the results of semen analysis cannot be used as a sole indication for ASA testing.

To test the effects of paromomycin, 10 patients with AIDS and cryptosporidiosis were randomized to paromomycin or placebo in a double-blind trial. After 14 days, patients were switched to the other treatment for 14 additional days. Measures included the number and character of each stool and weekly 24-h stool specimens for weight and oocyst excretion. During the paromomycin treatment phase, oocyst excretion decreased from 314 x 10(6) to 109 x 10(6)24 h (P < .02). Oocyst excretion increased for the 4 patients initially on placebo compared to a median decrease of 128 x 10(6)/24 h for the 6 initially treated with drug (P < .02). Stool frequency also decreased more in those treated with drug (3.6 fewer vs. 1.25 fewer/24 h, P < .05). Trends favored drug over placebo for stool weight, stool character, and Karnofsky score. Paromomycin treatment resulted in improvement in both clinical and parasitologic parameters in cryptosporidiosis in AIDS.

Background: The pathogenesis of intestinal cryptosporidiosis is not known. Previous studies have shown that the intensity of infection varies between patients. The hypothesis of this study is that intestinal injury is related to the intensity of infection., Methods: The histological abnormalities associated with Cryptosporidium infection were evaluated in duodenal biopsy specimens from 18 patients with acquired immunodeficiency syndrome-associated cryptosporidiosis. The intensity of Cryptosporidium infection was assessed histologically in all patients as the percentage of mucosa covered by organisms and by quantitation of oocyst excretion in the stools of 14 patients., Results: Duodenal biopsy specimens from 13 patients (72%) showed normal villous architecture. In these patients, the inflammatory component of the lamina propria was either normal or moderately increased. This increase consisted mostly of lymphocytes and plasma cells. Five of 18 patients (28%) had flattening of the mucosa associated with a prominent neutrophilic infiltrate. The intensity of infection in patients with villous flattening as measured from biopsy specimens and stool was significantly higher than in those without flattening (92% vs. 12% mucosa occupied with organisms; 738 x 10(3) vs. 199 x 10(3) oocyst/mL stool) (P < 0.004 in both cases)., Conclusions: Most patients with intestinal Cryptosporidium infection had normal duodenal villous architecture. Severe duodenal morphological abnormalities, including flattening of the villi, were associated with high-intensity infections.

Objective: To identify distinct criteria for appropriate on-scene termination of resuscitation efforts for out-of-hospital cardiac arrest when on-scene interventions fail to restore spontaneous circulation., Design: For 18 months, all out-of-hospital cardiac arrests were evaluated prospectively for survival to hospital discharge and for all established survival predictors including age, gender, presenting cardiac rhythm, whether it was a witnessed event, performance of basic cardiopulmonary resuscitation by bystanders, and interval to paramedic arrival and return of spontaneous circulation (ROSC)., Setting: A large municipality with a single, centralized emergency medical services program., Patients: All normothermic adults treated for out-of-hospital, unmonitored, primary cardiac arrest., Interventions: Standard advanced cardiac life support provided at the scene by paramedics., Main Outcome Measures: The number and circumstances of patients achieving survival to hospital discharge following failure to achieve on-scene ROSC., Results: Of 1461 consecutive primary cardiac arrests, 139 were monitored (paramedic witnessed), including 59 that occurred en route to the hospital. Of the 1322 unmonitored patients, 370 achieved ROSC at the scene. Only six (0.6%) of the 952 who did not achieve ROSC at the scene survived, and all six were readily identifiable as having persistent ventricular fibrillation. Excluding those patients with persistent ventricular fibrillation, all survivors achieved ROSC within 25 minutes after paramedic arrival., Conclusions: Excluding patients with persistent ventricular fibrillation, resuscitative efforts can be terminated at the scene when normothermic adults with unmonitored, out-of-hospital, primary cardiac arrest do not regain spontaneous circulation within 25 minutes following standard advanced cardiac life support. These criteria should now be validated in several large centers with high survival rates.

Multiple-choice crosses among five geographic strains of the housefly, Musca domestica L., were carried out in equal (10:10) and low-frequency (4:16) ratios. Initially, a low-frequency-male mating advantage was apparent, but further analyses related this minority advantage to a reduction of male mating success during marking by wing clipping. When there are fluctuating differences in the level of sexual vigor between competing male types over replicate trials of a cross, a mating advantage will accrue to the minority type. Even if males from the two competing strains are equally vigorous, such fluctuating differences will occur during sampling of flies. Harming the flies during marking will serve to enhance this effect and make significant departures toward greater mating success of rare males highly likely. This statistical bias in favor of minority males was substantiated in simulations of the KENCE-BRYANT model of mating success and compared with our results of a minority advantage in the housefly and with published results of a minority advantage in Drosophila. Our evidence, though circumstantial, that an advantage to minority males could have been induced by such an experimental bias suggests that a re-examination of existing data, as well as new experimentation, is necessary to discern whether or not a real rare-male advantage exists.