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Biomedical subjects

R D Horner

Publications and source records attributed to R D Horner.

At least 73 records · Page 4Linked to original sources
PubMed1991

Relationship between patient race and survival following admission to intensive care among patients of primary care physicians.

This study investigated the existence of racial differences in the survival of patients admitted to intensive care by family physicians and general internists for circulatory illnesses. The study population consisted of 249 consecutive patients admitted by these specialists to an ICU in a tertiary care hospital in Pitt County, North Carolina, during the June 1985 to June 1986 period. Logistic regression was used to specify the unique effect of race on ICU patient survival in-hospital, controlling for potential confounding factors such as disease severity, type of health insurance, and case mix. Black patients were almost three times more likely than white patients to die in-hospital following admission to the ICU (RR = 2.9, 95 percent I = 1.5, 5.6). Most of this difference in survival was explained by racial differences in disease severity.

Black People↗
PubMed1991

Billing practices of North Carolina family physicians.

BACKGROUND: This study describes billing practices of family physicians. Significant increases in the reimbursement for family physicians are expected from implementation of the resource-based relative value scale (RBRVS). However, the real impact of the RBRVS is unknown since little is known about how family physicians use the present reimbursement system to charge their patients. METHODS: A random sample of 270 North Carolina family physicians was surveyed, using standardized progress notes of five hypothetical patients. RESULTS: One hundred thirty-eight (51%) physicians responded; 107 (77.5%) were in private practice. Family physicians in private and nonprivate practices were similar in their Current Procedural Terminology (CPT) coding and level of service for each hypothetical case. Family physicians in smaller communities showed greater variation in CPT coding of visits than did family physicians in larger communities, and they were more likely to use CPT codes that indicated a lower level of visit. Rural family physicians demonstrated a significant inverse relationship between the CPT level of visit coded (ranging from "brief," with a CPT code of 90040, to "comprehensive," coded CPT 90080) and the amount they charged established patients for a "limited" visit (CPT 90050). CONCLUSIONS: These findings suggest that the lower income of rural physicians is due, in part, to billing at a lower CPT code, and thus charging less for comparable services, than urban physicians. The findings also lend further support to contentions that federal reimbursement reforms will have less impact on the incomes of rural physicians than originally expected.

Abstracting and Indexing↗
PubMed1990

Cancer mortality in Native Americans in North Carolina.

This paper describes age-adjusted mortality from malignant neoplasms for Native Americans in North Carolina for 1968-72 and 1978-82. Sex-specific standardized mortality ratios were calculated from death certificate data, using the cancer mortality experience of White North Carolinians to obtain the number of expected deaths. For most categories and specific sites of cancer, mortality was at or below the expected level, but higher than expected mortality was found for genitourinary cancers in males (SMR = 1.62, 95% CI = 1.15, 2.21) for the 1978-82 period; within this category, there was a higher than expected level of mortality from prostate cancer (SMR = 2.00; 95% CI = 1.36, 2.83) and cancer of the penis and other male genital organs (SMR = 9.09; 95% CI = 1.10, 32.84). Female Native Americans had an elevated mortality from cervical cancer (SMR = 2.27, 95% CI = 1.09, 4.17) for the 1968-72 period only.

Adolescent↗
PubMed1990

Implications of nuclear diameter in small cell lung carcinoma.

The nuclear diameter of 5,117 malignant cells from 42 small cell lung carcinoma (SCLC) patients was assessed either on pretreatment tissue sections (35 cases) or cytologic smears (7 cases) by ocular micrometry. The SCLCs were subtyped as 30 oat cell carcinomas and 12 intermediate cell carcinomas according to the World Health Organization classification, based on the predominant histology of the tumor. The median number of nuclei measured from each patient was 110. All patients were treated identically by sequential hemibody and local irradiation combined with chemotherapy and had a median follow-up time of 310 days. The mean nuclear diameter (+/- standard error) obtained from tissue sections was 8.2 +/- 0.03 microns (median = 8.0), including 7.3 +/- 0.03 microns (median = 7.0) for oat cell cases and 9.5 +/- 0.06 microns (median = 9.0) for intermediate cell cases (P less than .001). In 28.6% of these patients, the nuclear diameter overlapped in the range of 8 microns to 9 microns between both subtypes. Comparisons between the nuclear diameter of primary and metastatic SCLC cells revealed no statistically significant differences. The nuclear diameter of malignant cells correlated with the mitotic index and stage of disease, but did not correlate with the other nuclear morphologic variables or with survival. The only identified prognostic factor was the stage of disease; these results indicate that the nuclear diameter of malignant cells should not be considered a prognosticator or a guide for therapy in SCLC patients.

Adult↗
PubMed1990

Overlap of nuclear diameters in lung cancer cells.

The nuclear diameters (NDs) of randomly selected malignant cells from 35 cases of small-cell lung cancer (SCLC; 4,370 nuclei) and 31 cases of non-SCLC (NSCLC; 1,280 nuclei) were measured on the pretreatment tissue sections by ocular micrometry. The mean ND (+/- standard deviation) of malignant cells for SCLC patients was 8.1 +/- 1.5 microns; these cases included 23 oat-cell carcinomas and 12 intermediate-cell carcinomas. The ND of malignant cells for NSCLC patients was 12.8 +/- 2.2 microns; these cases included 17 squamous-cell carcinomas, 12 adenocarcinomas and 2 large-cell carcinomas. The differences of ND between SCLC and NSCLC and between intermediate-cell cancer and NSCLC were highly significant (P = 0.001). However, the malignant cells of 36 (54.5%) of the 66 lung cancer patients had NDs that overlapped in the range of 8 microns to 13 microns. For the 12 intermediate-cell patients, the NDs of the malignant cells overlapped with those of 8 (66.7%) of the 12 adenocarcinomas and 10 (58.8%) of the 17 squamous carcinomas. In contrast, the NDs of only 5 (21.7%) of the oat-cell patients overlapped with those of 5 (41.7%) of the 12 intermediate-cell cases and showed no overlap with NSCLC cases. Since there is overlapping of the nuclear diameters of malignant cells between SCLC and NSCLC patients, nuclear parameters other than the diameter are necessary to differentiate these two major histologic types of lung cancers.

Carcinoma, Non-Small-Cell Lung↗
PubMed1990

Implication of nuclear morphological characteristics in small cell lung cancer.

We report the pretreatment quantitative nuclear morphological findings of malignant cells from 42 patients with small cell lung cancer (SCLC) to evaluate their impact on the stage of disease, therapeutic response and survival as well as their interrelationships. The variables analysed were nuclear configuration, distinction of nuclear membrane, chromatin and its distribution, mitotic index and nucleolar index. All patients were treated uniformly with chemotherapy and hemibody irradiation. The series consisted of 30 OAT cell cancers and 12 intermediate cell cancers, according to the World Health Organization histological subclassification of SCLC. The morphological analysis used histological (n = 35) and cytological (n = 7) slides from either primary (n = 30) or metastatic (n = 12) tumors. A total of 5117 cancer nuclei (median = 110 per patient) were assessed. The SCLC subtype was significantly associated with a specific nuclear chromatin pattern, mitotic index and stage of disease. However, none of the evaluated nuclear morphological variables or the SCLC subtypes had therapeutic or survival impact. The stage of disease was the only factor which significantly correlated with the survival of SCLC patients.

Adult↗
PubMed1990

Influence of pentoxifylline on steady-state theophylline serum concentrations from sustained-release formulations.

This clinical study assessed the influence of pentoxifylline and its metabolites on steady-state serum theophylline concentrations. Nine healthy volunteers took sustained-release formulations of pentoxifylline, theophylline, and a combination of both agents each for 7 days at standard therapeutic doses in a randomized order. Serum theophylline concentrations were analyzed using fluorescence-polarization immunoassay (TDx) technique. During the pentoxifylline treatment phase, serum theophylline concentrations were undetectable, demonstrating the lack of assay interference from pentoxifylline and its metabolites. Mean trough steady-state serum theophylline concentrations were 30% higher (p less than 0.05) during the combination treatment phase compared to theophylline administration alone, and varied considerably. Although side effects were more frequent during the combination phase, differences in the number of adverse reactions did not achieve statistical significance. This study demonstrates an interaction between theophylline and pentoxifylline, and indicates that close monitoring of serum theophylline concentrations during combination therapy is warranted.

Adolescent↗
PubMed1990

Test of cure for genital Chlamydia trachomatis infection in women.

Convenient, reliable tests of cure for genital chlamydial infections have not been evaluated. Cervical appearance, endocervical Gram stain, enzyme immunoassay, and culture for Chlamydia trachomatis were evaluated during a pretreatment visit and at two subsequent randomized test-of-cure visits for 64 nongravid women with endocervical C trachomatis of 3544 patients screened. There were no useful correlations between C trachomatis resolution and cervical appearance. Endocervical Gram stain was determined to be unreliable for test-of-cure use. Both C trachomatis culture and enzyme-linked immunosorbent assay (ELISA) were shown to be effective for test-of-cure evaluation. The ELISA test became reliably negative 10 days after initiation of treatment and 1 to 5 days after the clearance of viable organisms detected by culture (P = .03). Convenience and cost considerations favor antigen detection methods. This study suggests that antigen detection methods can be used for situations in which test of cure is indicated, such as therapy noncompliance, circumstances supporting reinfection, pregnancy, complicated infections, requests for psychological reassurance, and evidence of persistent cervicitis.

Chlamydia Infections↗
PubMed1990

Physician referrals from a rural family practice residency clinic: a pilot study.

Primary care physicians see large volumes of unscreened patients in the office setting, and referral to more specialized colleagues is always an option. Discretionary factors may play an important role in the referral decision. In this study, three family physicians retrospectively rated 410 referrals from a rural academic practice for the need for referral based on lack of specialized skills or knowledge by family physicians and the probability of adverse patient outcome. Referrals relating to cancer and pregnancy were rated as less discretionary than other referrals. Specialties receiving the highest proportion of mandatory or probably mandatory referrals were ophthalmology and cardiology. Half of all referrals studied were considered to be elective or possibly elective, although 97 percent of referrals to dermatology were considered elective or probably elective. These findings support the hypothesis that there is considerable clinical discretion in a large proportion of referrals. Hence, imposition of specific criteria for referral in primary care practice (thereby limiting discretion in initiating a referral) could significantly decrease the number of referrals, and consequently decrease the income of subspecialists and tertiary care centers.

Adult↗
PubMed1989

Morphometric and morphologic evaluations in stage III non-small cell lung cancers. Prognostic significance of quantitative assessment of infiltrating lymphoid cells.

This study evaluated data from 30 non-small cell lung cancer (NSCLC) patients to determine whether demographic, clinical, and morphologic and morphometric data that were obtained prior to treatment, could be used to predict survival. All patients had Stage III disease, and all subsequently were treated identically with concurrent radiotherapy, cisplatin, and 5-fluorouracil. The series consisted of 18 squamous carcinomas, eight adenocarcinomas, and four large cell carcinomas. Morphometric measurements of randomized selected cancer cells per case included diameter of cytoplasm, nuclei, and nucleoli. Morphologic parameters evaluated were mitotic index, histologic differentiation, and pattern of nuclear chromatin of cancer cells, and the degree of necrosis and fibrosis of tumor tissue. The lymphoid and neutrophil index defined as the ratio of lymphoid cells and neutrophils to cancer cells from randomized microscopic fields (median = 25) at 400 x magnification were also determined. Our study indicated that the peritumor lymphoid index was the only factor significantly associated with the length of survival. The correlation coefficient (Pearson r) of these two factors was 0.5 (P less than 0.005). The median survival time of patients with peritumor lymphoid index less than 3 and greater than or equal to 3 was 95 days and 376 days, respectively (Kaplan-Meier estimation). The peritumor lymphoid index was an independent prognosticator of clinical outcome of Stage III NSCLC patients, and did not correlate with any of the other parameters analyzed.

Adenocarcinoma↗
PubMed1988

Impact of federal primary health care policy in rural areas: empirical evidence from the literature.

This review examines the equity, efficiency and effectiveness of federal rural primary care policy as documented by the existing literature. The focus is on the Community Health Center and National Health Service Corps programs which have constituted the major components of the policy. The literature relating to the policy is limited in the number of studies available and in the quality of the research. The available evidence indicates that the policy is associated with an improvement in the distribution of health resources between rural and urban areas,and among rural areas. There is also partial evidence that the policy has been cost-efficient. For federally subsidized practices,the cost of delivering a similar quality of health care is shown to be up to 50 percent less in rural than in urban areas. Rural private practitioners, though, may be more cost-efficient than federally subsidized rural practitioners, at least under certain conditions which have yet to be fully delineated. Program effectiveness is the least well documented, but the literature does suggest that the policy has had a positive effect on the health status of rural populations. Substantially more research on the efficiency, and particular the effectiveness, of federal rural primary care policy is required for the development of a rational basis for the policy.

Community Health Centers↗
PubMed1988

Diuretics and hypertension in black adults.

A randomized controlled, single-blind trial was conducted to compare the effectiveness of a high-dose diuretic with a combination of a diuretic and metoprolol in black adults with hypertension. All subjects were first treated with 50 mg/d of hydrochlorothiazide for four weeks. Only subjects with a diastolic blood pressure of 95 mm Hg or higher at the end of this four-week period entered the randomized trial. We hypothesized that black patients with uncontrolled hypertension and low plasma renin activity on usual-dose hydrochlorothiazide therapy (ie, 50 mg/d) would respond better to higher doses of hydrochlorothiazide (ie, 100 to 150 mg/d) than to a usual-dose diuretic and metoprolol. Diuretic-metoprolol combination therapy was significantly more effective than high-dose diuretic therapy regardless of plasma renin status.

Adult↗
PubMed1987

Survivorship differences in geographical comparisons of cancer mortality: an urban-rural analysis.

Epidemiologists have traditionally used geographical comparisons of cancer site-specific mortality rates to draw aetiological inferences about neoplasms. This approach is based on the unproven assumption that cancer mortality and incidence rates are highly correlated within geographical areas. Since mortality is a function of both incidence and survival rates, geographical differences in cancer survivorship may confound area comparison of cancer mortality rates. To test this possibility, the survival experience of white male cancer patients residing in rural and urban areas is examined using cancer registry data. A multi-variable proportional hazards model is specified to determine the unique effect of geographical residence on survival. Only for cancers of the gastro-intestinal (GI) tract are there statistically significant differences in survivorship by geographical residence. This suggests that for most cancers, survival differences are not likely to play a confounding role in geographical comparisons of cancer mortality rates. However for GI cancers, survival differences should probably be considered in geographical-oriented analyses and their interpretation.

Health↗
PubMed1987

Age at onset of Alzheimer's disease: clue to the relative importance of etiologic factors?

Clues to the relative importance of possible etiologic factors for dementia of the Alzheimer type may be gained by examining the fit of case series to Sartwell's model of the distribution of incubation periods. If age at disease onset is used as the incubation period of this disease, a genetic or environmental factor acting during the prenatal period is suggested if the distribution of these ages fits the lognormal curve; otherwise, environmental factors acting after birth are implicated. Case series were identified from the literature. Four case series were found which contained sufficiently detailed data to permit this secondary analysis; only one case series was population-based. The distribution of age at disease onset for each series was graphically and statistically assessed for fit to the logarithmic normal distribution. Each case series fit the lognormal curve well. This suggests that research into the etiology of dementia of the Alzheimer type should focus on the prenatal experiences of patients with this disease.

Adult↗
PubMed1986

Effects of permeant buffers on the initiation of photosynchronous phosphorylation and postillumination phosphorylation in chloroplasts.

Under canonical chemiosmotic formulations, the development of a delocalized transmembrane proton gradient should precede and, in the absence of a membrane potential, should account for all the capacity of an energy transducing system to synthesize ATP. Furthermore, any agents, such as permeant proton-absorbing buffers, that slow down the kinetics of the development of this gradient should, consequently, delay ATP synthesis. We have studied the very early (0 through 1000 ms) steps of photosynthetic ATP synthesis utilizing real-time, rapid flow-quench techniques. We have investigated the effect(s) that permeant buffers exert on this process where these buffers show no uncoupling effects, and the transmembrane potential has been collapsed by valinomycin and K+. Experimentally this system was dissected into two ATP synthesizing components, as follows: synthesis of ATP strictly concomitant with light influx and unaffected by the addition of permeant buffers. We refer to this as photosynchronous phosphorylation and synthesis of ATP monitored after the light was extinguished and which was greatly diminished by the addition of proton-absorbing permeant buffers, thus exhibiting the characteristics of conventional postillumination phosphorylation, and we suggest that it represents part of capacitance phosphorylation. The potential for capacitance phosphorylation initiates very rapidly under light and gradually builds up to steady-state level, and it is governed by canonical chemiosmotic principles. We estimate that its contribution to overall ATP yield is minimal during the first few cycles of the system and that it increases gradually towards steady state when it contributes to the majority of ATP synthesized. Neither a delocalized transmembrane proton gradient nor a strictly localized intramembrane proton pathway can account for these observations so we have proposed that a gating mechanism exists which delivers intramembrane protons initially directly to the ATP synthetase complex but subsequently to the lumen as well, and thus, allows the lumen to act as a capacitor during the steady state. This study can reconcile the findings of Ort et al. (Ort, D. R., Dilley, R. A., and Good, N. E. (1976) Biochim. Biophys. Acta 449, 108-124) with the contrasting findings of Vinkler et al. (Vinkler, C., Avron, M., and Boyer, P. D. (1980) J. Biol. Chem. 255, 2263-2266) through the opposite effects which osmotic strength and KCl concentration exert on the two ATP synthetic phases (during and after illumination) of the rapid flash technique used in those studies.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Triphosphate↗
PubMed1985

Economic status and survivorship in digestive system cancers.

This study investigates economic differentials in cancer survival in a sample of 1180 white men, focusing in particular on the relationship between income level and survivorship in the various subsites comprising the digestive system cancer category. Using the Cox proportional hazards model to control for confounding variables, the economic status-survivorship relationship is estimated for several subgroupings of primary malignancies. The results show significant variation in this relationship across different cancer sites, with a pronounced effect observed in carcinomas of the small intestine, peritoneum and, especially, colon and rectum. High-income patients with these malignancies had a significantly lower risk of dying from the disease (P less than 0.05) than either their middle- or lower-income counterparts, controlling for age, stage, and initial course of treatment. Differences in immunologic status, tumor characteristics, and follow-up treatment may account for these economic effects.

Age Factors↗