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Biomedical subjects

M E Miller

Publications and source records attributed to M E Miller.

At least 109 records · Page 6Linked to original sources

Injecting drug users and HIV/AIDS: risk behaviours and risk perception.

This paper reports on the incidence of risk taking behaviours, and the relationship between risk perception and risk behaviours in a sample of 1245 Sydney injecting drug users (IDUs). Almost all respondents reported engaging in behaviours that placed them at risk of HIV infection: 32.9% through unsafe injecting, 84.4% because of unsafe sexual behaviour and 89.2% because of either injecting or sexual behaviour. Injecting and sexual behaviour were poorly correlated. This study also found that risk perception is unrelated to injecting or sexual behaviours, previous history of sexually transmitted diseases, a range of demographic characteristics including age and gender, and the number of times tested for HIV. Social policy and prevention programs should aim to change unsafe injecting and sexual behaviours directly, rather than attempting to achieve change indirectly by changing risk perception.

AIDS Serodiagnosis↗

Hypnotic analgesia: dissociated experience or dissociated control?

High-hypnotizable subjects (n = 18) were superior to low-hypnotizable subjects (n = 18) in the extent of pain reduction produced by hypnotic analgesia and by a stress-inoculation procedure. However, stress inoculation but not hypnotic analgesia impaired performance on a cognitively demanding task that competed with pain reduction for cognitive resources. This outcome implies that hypnotic analgesia occurs with little or no cognitive effort to reduce pain and challenges the social psychological model of hypnosis. The findings are also inconsistent with the notion of dissociated experience, which proposes that pain and the cognitive efforts to reduce it are cut off from consciousness by an amnesialike barrier. However, the results do support the notion of dissociated control, which proposes that suggestions for hypnotic analgesia directly activate pain reduction and thereby avert the need for cognitive strategies to reduce pain.

Adult↗

Carboplatin (CBDCA) plus alpha interferon in metastatic non-small cell lung cancer. A Hoosier Oncology Group phase II trial.

Interferons have been shown to increase in vitro cytotoxicity of platinum compounds. The Hoosier Oncology Group has conducted a Phase II clinical trial to determine if interferon alpha-2a (IFN-alpha-2a) given in combination with carboplatin (CBDCA) can increase response rates or survival in patients with metastatic or recurrent inoperable non-small-cell lung cancer. Forty-four patients with no prior chemotherapy and high KPS (80-100) were enrolled. CBDCA 400 mg/m2 was given intravenously on day 1 and IFN-alpha-2a 9 million units was given subcutaneously on days 1, 3, and 5. Treatment was administered every 4 weeks until onset of progressive disease or to a maximum of 4 courses: 37 patients (84%) received at least 2 courses, whereas only 16 (36%) received the full 4 courses. Dose-limiting toxicities were leukopenia (27%) and thrombocytopenia (20%) attributable to CBDCA. Grade 2-3 anemia occurred in 32%. Only 4-7% of patients experienced severe fever, fatigue, or flu-like symptoms attributable to interferon administration. Of 41 patients evaluable for response, there were no complete responses and only 3 (7.3%) partial remissions. The overall median survival was 6 months. The combination of CBDCA and IFN-alpha-2a given in this dose and schedule does not appear to have superior activity compared to CBDCA alone in patients with non-small-cell lung cancer.

Adult↗

Posterior pelvic fixation using a transiliac 4.5-mm reconstruction plate: a clinical and biomechanical study.

Operative management of unstable pelvic fractures is directed toward stabilization of the posterior lesion. We describe a technique of posterior pelvic fixation that uses a 4.5-mm reconstruction plate as a transiliac tension band. The plate is inserted through the posterior superior iliac spines with screw fixation to the ilium. Our initial clinical experience was gained using this technique in 15 patients who had unstable pelvic ring injuries with sacral fractures. Stable fixation was achieved in all patients with this low-profile plate. There were no infections, no wound complications, and no failures of fixation. Comparative biomechanical testing using cadaveric and artificial pelvises demonstrated that the strength of the transiliac plate method was equal to that of other techniques of posterior pelvic fixation.

Adult↗

Estimating physician costliness. An empirical Bayes approach.

Outpatient data obtained from the general medicine practice of an urban, health care facility are used to provide an application of empirical Bayes techniques in the estimation of physician "costliness." The results illustrate that application of the simplest empirical Bayes estimation procedure can provide more reasonable estimates of physician's utilization of resources than a standard estimation procedure. Empirical Bayes estimates are shown to adjust for potential instability in standard estimates that may arise from either a physician treating a small number of patients or an inappropriate case-mix adjustment. Using simulation, it is demonstrated that the empirical Bayes procedure can provide overall better estimates using fewer data than the standard procedure. This application, although somewhat limited in scope, should provide impetus for increased utilization of the numerous Bayesian and empirical Bayes techniques that currently exist in the statistical literature and pertain to small area estimation techniques.

Ambulatory Care↗

How do Medicare physician fees compare with private payers?

Under the new fee schedule, Medicare physician fees are 76 percent of private fees. Consistent with the intent of payment reform, Medicare physician fees more closely approximate private fees for visits (93 percent) than for surgery (51 percent) and in rural areas as compared with large metropolitan areas. Variation in private fees across the country is considerably greater than it is for Medicare fees. Consequently, Medicare fees are most generous in areas that compare least favorably with the private market because private fees in these areas are well above average. These results shed light on the impact of the fee schedule and on the implications of using Medicare payment methods as part of a broad-based health reform.

Data Interpretation, Statistical↗

Medicaid case management: Kentucky's Patient Access and Care Program.

Since 1981, States have been experimenting with Medicaid managed care programs to improve access and continuity of care and to contain costs by reducing inappropriate and unnecessary utilization. To determine the impact of primary care case management (PCCM) on utilization, the authors examine data from the Kentucky Patient Access and Care program (KenPAC). Using monthly utilization data from 1984 to 1989 and an interrupted time-series research design, the authors find that PCCM reduces the use of independent laboratory, physician, emergency department, and outpatient hospital services. PCCM does not appear to affect utilization of inpatient hospital services or prescription drugs.

Health Services Accessibility↗

Medicare inpatient physician charges: an econometric analysis.

To control Medicare physician payments, Congress in 1989 established volume performance standards (VPS) that tie future physician fee increases to the growth in expenditures per beneficiary. The VPS risk pool is nationwide, and many observers believe it is too large to affect behavior. VPS could be modified by defining a separate risk pool for inpatient physician services and placing each hospital medical staff at risk for those services. Using a national random sample of 500,000 Medicare admissions, we explore the determinants of medical staff charges and comment on the policy implications. Multivariate analysis shows that charges increase with case mix and bed size but, surprisingly, decrease with the level of teaching activity. The teaching result is explained by the substitution of residents for physicians in these hospitals.

Analysis of Variance↗

The analysis of longitudinal polytomous data: generalized estimating equations and connections with weighted least squares.

In recent years, methods have been developed for modelling repeated observations of a categorical response obtained over time on the same individual. Although situations in which the repeated response is binary or Poisson have been studied extensively, relatively little attention has been given to polytomous categorical response variable. In this paper, we extend the estimating equations initially developed for clustered discrete data by Liang and Zeger (1986, Biometrika 73, 13-22), and subsequently extended by Prentice (1988, Biometrics 44, 1033-1048), to polytomous response variables. Under certain assumptions, we illustrate that these estimating equations simplify to the weighted least squares (WLS) equations formalized by Koch et al. (1977, Biometrics 33, 133-158). This connection provides a formal framework for obtaining iterated weighted least squares model parameter estimates. Cumulative logit models are developed and applied to a representative longitudinal data set. Simulation results comparing WLS, an iterative form of WLS, and independence estimating equations using a robust estimate of the variance are presented.

Analysis of Variance↗

Growth in Medicare inpatient physician charges per admission, 1986-1989.

Recently, there has been increasing interest in alternative Volume Performance Standards centered around the hospital medical staff. Using a national sample of Medicare claims, this paper analyzes growth in Medicare inpatient physician charges per admission between 1986 and 1989, by specialty, type of service, and type of hospital. Although growing more slowly than outpatient services, inpatient physician service volume and intensity growth is substantial. Inpatient physician services grew at an annual rate of 8.3%-31% of which was attributable to prices, 27% to case mix, and 41% to volume and intensity. Services provided by cardiologists, gastroenterologists, and other medical specialists demonstrate annual volume and intensity increases exceeding 13% annually. Consultations, hospital visits, and specialist services account for a third of all services provided during the admission and also demonstrate rapid annual rates of growth.

Diagnosis-Related Groups↗

A comparison of drug use and HIV infection risk behavior between injecting drug users currently in treatment, previously in treatment, and never in treatment.

We compared three groups of injecting drug users in a large cross-sectional study on HIV/AIDS and risk behaviors in Sydney, Australia, to determine what differences existed between those who had never been in treatment (n = 458), had previously been in treatment (n = 387), and were currently in treatment (n = 367). Drug use for those currently in treatment was assessed during the last typical using month before treatment. Those previously and currently in treatment were similar in terms of drug use patterns and HIV risk-related injecting behaviors. Those never in treatment were younger, had a lower level of HIV risk-related injecting behaviors, and reported lower drug use and less involvement in the drug subculture. There was little difference between the three groups on HIV risk-related sexual behaviors. These data suggest that those never in treatment are less dysfunctional and possibly less involved in drug-using careers, whereas there appears to be a close relationship between being previously and currently in treatment.

Adult↗

An infant with trisomy 9 mosaicism presenting as a complete trisomy 9 by amniocentesis.

We present a case in which amniocentesis performed at 33 weeks' gestation because of symmetrical intrauterine growth retardation and decreased amniotic fluid volume led to the prenatal diagnosis of a fetus with a karyotype of 47,XX,+9,t(1;20)(q42;p11.2) pat, i.e., with an extra chromosome 9 and a balanced translocation between chromosomes 1 and 20. At delivery, the baby showed clinical features of trisomy 9, yet chromosome analysis of the cord blood revealed no trisomy 9 cells, a finding confirmed by neonatal blood karyotyping. The balanced translocation was present in all cells. A skin biopsy confirmed trisomy 9 mosaicism with 10 per cent trisomy 9 cells. The baby died at 6 weeks and an autopsy was obtained. Chromosome analysis of different organs demonstrated different frequencies of the mosaicism of trisomy 9. The possible underlying mechanism for the discrepancy between the karyotype results by amniocentesis and those of other tissues is discussed.

Adult↗

Gigantic osteoma of the mandible: report of a case.

A case of a very large solitary osteoma of the right posterior mandible in a 22-year-old man is presented. The tumor was asymptomatic despite its location and large size. It was removed via an extraoral Risdon approach without complication. The importance of differentiating a large solitary osteoma from a parosteal osteogenic sarcoma is emphasized. Any patient presenting with a solitary osteoma also should be evaluated for Gardner's syndrome.

Adult↗

Differences across sexual orientation on HIV risk behaviours in injecting drug users.

Injecting drug users (IDUs) play a disproportionate role in the spread of HIV given their injecting and sexual contacts, and thereby act as conduits between these risk groups. We investigated differences in risk behaviour and HIV seroprevalence in a Sydney sample of 1,245 IDUs. Significant differences were observed across sexual orientation in HIV serostatus for males, with homosexual men having the highest HIV seroprevalence rate (35%), bisexual men intermediate (12%) and heterosexual men lowest (3%). Sexual HIV risk behaviours were lowest for homosexual men, intermediate for bisexual men, and highest for heterosexual men in the case of condom use: however, for numbers of partners, seroprevalence, and anal sex the trends were reversed. There were no differences across sexual orientation for either sex for injecting drug risk behaviours. Both male and female respondents reported having more than 50% of sexual contacts while under the influence of drugs. This study suggests that risk reduction in the sexual domain has not generalized to the injecting risk domain regardless of sexual orientation, and demonstrates that sexual risk behaviours in IDUs are lowest in homosexual, intermediate in bisexual, and highest in heterosexual IDU men.

Adult↗

Frequency of medium-chain acyl-CoA dehydrogenase deficiency G-985 mutation in sudden infant death syndrome.

A small percentage of apparent sudden infant death syndrome (SIDS) victims may have an unsuspected metabolic disorder. Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is a disorder of fatty acid oxidation that has been the most common such metabolic disorder found in series of SIDS victims. A single mutation in MCAD deficiency has been recently described (G-985) that accounts for approximately 90% of MCAD deficiency mutations. We studied the hypothesis that heterozygosity or homozygosity for this specific MCAD deficiency mutation might be associated with SIDS. DNA was extracted from the paraffin-embedded autopsy tissues of 67 victims of SIDS in Monroe County, NY who died between 1984 and 1989. Using the polymerase chain reaction/NcoI digestion method, we found no G-985 homozygotes and three (4.5%) G-985 heterozygotes. In 70 newborn controls, there were no G-985 homozygotes and one (1.4%) heterozygote. Although the frequency of G-985 heterozygotes was slightly greater than in our control group, it was not statistically different. We conclude that the specific MCAD deficiency mutation G-985 is not strongly associated with SIDS and that MCAD deficiency probably does not make a significant contribution to the etiology of SIDS.

Acyl-CoA Dehydrogenase↗