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Biomedical subjects

K Hornbuckle

Publications and source records attributed to K Hornbuckle.

9 recordsLinked to original sources
PubMed2001

Influenza vaccine effectiveness among elderly nursing home residents: a cohort study.

Outbreaks of influenza in nursing homes still occur, even when a large portion of residents have been inoculated with inactivated vaccine. Data were collected in 1991--1992 from 83 eligible skilled nursing homes located in southern Lower Michigan to determine the effectiveness of inactivated influenza vaccine in preventing influenza-like illness and influenza-associated pneumonia. Surveillance was conducted to identify the occurrence of influenza in the homes and, at the end of the season, specific data were gathered on all residents of homes with influenza activity. Age- and sex-adjusted estimates of vaccine effectiveness were calculated using Cox proportional hazards models for each nursing home. Estimates were pooled using precision-based weights calculated from data for each home. Vaccine was found to be 33% effective in preventing total respiratory illness (influenza-like illness and clinically diagnosed pneumonia). In prevention of pneumonia alone, vaccine was 43% effective. The estimate for prevention of pneumonia rose to 55% if the period under consideration was limited to the time of peak influenza activity. Given the number of eligible homes and the cohort methodology used, the results support continuation of current policy, encouraging use of vaccine in all nursing home residents.

Age Distribution↗
PubMed2000

Biological derivation of a range of cephalometric norms for children of African American descent (after Steiner).

The purpose of this study was to report a normal range of anteroposterior apical base differences and concomitant interincisor inclinations and locations derived from a sample of American children (12 to 16 years) of African descent with normal occlusion (statistically defined). Standard cephalometric radiographs of 40 boys and 40 girls were traced and the Steiner Analysis performed. In addition to the ANB angle, 6 supplemental anteroposterior apical base separation estimators were measured, mean values established, and correlation (r) associations performed. The range of anteroposterior apical base difference was -0.5 degrees to 9.5 degrees estimated by the ANB angle or a linear distance of +/-6.5 mm using the Wits Appraisal. The angular and linear distance of the upper incisor to NA line (compensations) ranged from a low of 12 degrees and 3 mm to a high of 39 degrees and 14 mm. The angular and linear distance of the lower incisor to the NB line ranged from a low of 17 degrees and 3 mm to a high of 47.5 degrees and 17.5 mm. Biologically, the results suggested a wide range of equally acceptable sagittal apical base relationships and associated compensations in upper and lower incisor inclinations; normal occlusion was viewed as the reference point. Considering the usage of such descriptive terms as "ideal," "acceptable compromises," and "individualized treatment goals," to describe the angulation and inclination of the incisor teeth, the need for a distinction between biologically derived reference norms and esthetic preference reference norms is apparent when analyzing normal occlusion.

Adolescent↗
PubMed2000

The diagnosis and work-up of the patient with gastroparesis.

Gastroparesis-or delayed gastric emptying--is associated with upper gastrointestinal symptoms that include early satiety, nausea, vomiting, regurgitation, fullness, and bloating. Gastroparesis should be considered in the diagnosis of a patient with these symptoms after mechanical and structural lesions have been ruled out. This review briefly summarizes gastric motor physiology and discusses the etiology and diagnostic approach to the treatment of a patient with possible gastroparesis. We highlight the methods available to measure gastric motility and describe their relative advantages and disadvantages.

Diabetes Complications↗
PubMed1998

Determination and validation of a predictive model for Clostridium difficile diarrhea in hospitalized oncology patients.

BACKGROUND: Clostridium difficile colitis in the cancer patient receiving chemotherapy is a frequent cause of morbidity which may prolong hospitalization. Techniques for identifying infection often delay the initiation of therapy. PATIENTS AND METHODS: In this retrospective case-control analysis, we identified predictors for C. difficile-associated diarrhea in 29 patients hospitalized from 1988 to 1993 on a hematologic malignancy/bone marrow transplant unit (hospital A). We then validated our model with 58 C. difficile cases and 74 controls admitted to an oncology unit from a different institution (hospital B). RESULTS: We found that low intensity of chemotherapy (P < 0.001), lack of parenteral vancomycin use (P = 0.03) and hospitalization within the past two months (P = 0.05) were independently predictive of C. difficile colitis by multivariate analysis. These variables were weighted for predictive capability using a receiver operator characteristic score; low intensity chemotherapy was assigned two points, lack of parenteral vancomycin received one point and prior hospitalization one point (P < 0.001 by chi 2 for trend). The receiver operating characteristic (ROC) curve areas were 0.78 for patients at hospital A and 0.70 at hospital B indicating moderate drop off in discrimination. Compared to hospital A patients, hospital B patients hospitalized between 1989 and 1994 were more often women (P = 0.04), received less systemic vancomycin (P = 0.01), were less frequently neutropenic (P < 0.05), and received less intense chemotherapy regimens (P < 0.05). Despite these differences in demographics in patients between these institutions, our predictive model was validated in hospital B patients (P = 0.02 by chi 2 for trend). CONCLUSIONS: The results of this study may help clinicians predict the risk of C. difficile disease in the hospitalized immunocompromised oncology patient and may help guide empiric therapy while awaiting results of stool toxin assays.

Case-Control Studies↗
PubMed1995

Safety and efficacy of long-term use of rimantadine for prophylaxis of type A influenza in nursing homes.

The safety and efficacy of rimantadine for long-term prophylaxis of influenza A (H3N2) infection were evaluated among elderly residents in 10 nursing homes. Within each nursing home, participating residents were randomly assigned to receive placebo or rimantadine at 100 or 200 mg/day. Residents were evaluated daily for symptoms and significant health events as possible side effects, as well as for influenza-like illness. The study medications were administered to 328 residents for up to 8 weeks, with no statistically significant differences in the frequencies of gastrointestinal or central nervous system symptoms between the groups. However, residents in the active medication groups were more likely to withdraw from the study and to experience various health events including death; some but not all of these differences were statistically significant. Efficacy evaluations were carried out on the 68 vaccinated residents in the two nursing homes with demonstrated influenza virus activity. Rimantadine appeared to provide an additional protective effect beyond vaccination in reducing the risk of clinical and laboratory-confirmed influenza-like illness; however, the efficacy estimates were never statistically significant. The efficacies of the 100- and 200-mg/day dosages were generally similar. When data for the 100- and 200-mg/day dosage groups were combined and compared with data for the group receiving placebo, the efficacy of rimantadine in reducing the risk of clinical influenza-like illness was estimated to be 58 percent (P = 0.079). The results suggest the relative safety and clinical efficacy of using rimantadine for influenza prophylaxis among vaccinated elderly individuals and support the recommendation for a dosage reduction to 100 mg/day in this population.

Aged↗
PubMed1994

The joint effects of race and age on the risk of end-stage renal disease attributed to hypertension.

To describe the joint effects of race and age on the risk of end-stage renal disease (ESRD) attributed to hypertension (ESRD-HT), we analyzed data for white and black adults, 20 to 84 years of age, reported by the United States Renal Data System during the period 1987 to 1990. The risk of ESRD-HT increased substantially with age for both blacks and whites; however, at each age, the risk was greater for blacks. A more in-depth description of the combination of effects involving race and age on ESRD-HT incidence was provided by two models of joint effects, one additive and the other multiplicative. Both models used the 20- to 24-year age group as the referent. Under the additive model the risk of ESRD-HT in blacks attributable to the joint effects between race and age increased continuously from younger to older groups. This indicates that although ESRD-HT risk increases with age for both blacks and whites, the increase for blacks is greater than expected if the effects of race were independent of the effects of age. However, the multiplicative model indicated that the proportional increase with age in ESRD-HT risk among blacks, as compared with whites, was more striking for younger ages (< or = 50 years among women and < or = 40 years among men), and especially so for men. This suggests a more accelerated course of hypertension toward ESRD for blacks (especially younger men) than for whites. A conceptual model to explain these patterns of race-age joint effects is proposed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Role of countercurrent multiplication in renal ammonium handling: regulation of medullary ammonium accumulation.

Ammonium (NH3 plus NH4+), produced predominantly in the proximal tubule, is transferred to the final urine by a process involving countercurrent multiplication of ammonium which generates an ammonium concentration gradient in the renal medulla. It was hypothesized that if urinary ammonium excretion rates are controlled in part by the medullary ammonium gradient, changes in hydration and acid-base state should cause changes in the medullary ammonium gradient consistent with expected changes in urinary ammonium concentrations. To test that hypothesis, rats were subjected to water diuresis, water deprivation, water deprivation plus furosemide, and dietary acid and base loads and corticomedullary ammonium gradients in their kidneys were then measured. Sections were cut along the corticomedullary axis to yield slices of cortex, outer stripe of outer medulla, inner stripe of outer medulla, and three levels of the inner medulla. The total ammonia content of homogenized slices was measured by either a membrane ammonia electrode or an enzymatic technique. Kidneys from water-deprived animals showed a distinct ammonium gradient along the corticomedullary axis, with the highest contents found at the tip of the papilla. The gradient was attenuated by water diuresis and abolished by furosemide. Acid loading enhanced the gradient, and base loading abolished it. These results indicate that the corticomedullary ammonium gradient is regulated in response to changes in hydration and acid-base state.

Acid-Base Equilibrium↗