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Biomedical subjects

R J Dworkin

Publications and source records attributed to R J Dworkin.

At least 19 recordsLinked to original sources
PubMed2001

Phenotypic resistance of Staphylococcus aureus, selected Enterobacteriaceae, and Pseudomonas aeruginosa after single and multiple in vitro exposures to ciprofloxacin, levofloxacin, and trovafloxacin.

The phenotypic resistance of selected organisms to ciprofloxacin, levofloxacin, and trovafloxacin was defined as a MIC of > or =4 microg/ml. The dynamics of resistance were studied after single and sequential drug exposures: clinical isolates of methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA), Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Serratia marcescens, and Pseudomonas aeruginosa were utilized. After a single 48-h exposure of a large inoculum to four times the initial MIC for the organism, the frequency of selection of resistant mutants of MSSA was greater for trovafloxacin than levofloxacin (P = 0.008); for E. cloacae, the frequency was highest for ciprofloxacin and lowest for levofloxacin and trovafloxacin; for S. marcescens, the frequency was highest for trovafloxacin and lowest for ciprofloxacin (P = 0.003). The results of serial passage experiments were analyzed both by the Kaplan-Meier product-limited method as well as by analysis of variance of mean inhibitory values. By both methods, MSSA and MRSA expressed mutants resistant to ciprofloxacin after fewer passages than were required for either levofloxacin or trovafloxacin. For the aerobic gram-negative bacilli, two general patterns emerged. Mutants resistant to trovafloxacin appeared sooner and reached higher mean MICs than did mutants resistant to levofloxacin or ciprofloxacin. Mutants resistant to ciprofloxacin appeared later and reached mean MICs lower than the MICs of the other two drugs studied. Even though individual strain variation occurred, the mean MICs were reproduced when the serial passage experiment was repeated using an identical panel of E. coli isolates. In summary, the dynamic selection of fluoroquinolone-resistant bacteria can be demonstrated in experiments that employ serial passage of bacteria in vitro.

Anti-Infective Agents↗
PubMed1998

A randomized comparison of the safety and efficacy of once-daily gentamicin or thrice-daily gentamicin in combination with ticarcillin-clavulanate.

PURPOSE: The primary purpose of the clinical trial was to assess the safety and efficacy of once-a-day compared with three-times-a-day gentamicin in patients with serious infections who had protocol-determined peak serum aminoglycoside concentrations. PATIENTS AND METHODS: A total of 249 hospitalized patients with suspected or proven serious infections were randomized in a 2:2:1 ratio to gentamicin given three times a day with ticarcillin-clavulanate (TC), gentamicin once a day with TC, or ticarcillin-clavulanate (TC) alone. The gentamicin once-a-day dosage for patients with estimated creatinine clearance values of > or =80 mL/min was 5.1 mg/kg. With lower creatinine clearance estimates, the mg/kg dosage of gentamicin was decreased, and the dosage intervals (once daily or three times a day) were maintained. Evaluability required documentation of achievement of protocol-defined peak serum gentamicin levels. RESULTS: Of the total 175 evaluable patients, there were no significant differences found between treatment regimens with respect to clinical or microbiologic efficacy. Bedside audiometry proved impractical due to the frequency of altered mental state in ill patients. Based on the traditional increase in serum creatinine values from baseline values, no differences in renal toxicity between the treatment groups was identified. When changes in renal function were reanalyzed based on maintaining, as opposed to worsening, of renal function, preservation of renal function was better in the gentamicin once-a-day patients as opposed to the gentamicin three-times-a-day patients, P <0.01. CONCLUSIONS: Gentamicin once a day plus TC, gentamicin three times a day plus TC, and TC alone had similar effects in seriously ill hospitalized patients. The incidence of nephrotoxicity was similar in the three treatment groups. Using a nonvalidated post-hoc analysis, renal function was better preserved in gentamicin once-a-day + TC and TC-only patients as opposed to gentamicin three-times-a-day + TC.

Adult↗
PubMed1995

Staphylococcus aureus septic arthritis in patients on hemodialysis treatment.

We retrospectively reviewed hospital discharge diagnoses of septic arthritis over an 11-year period (1982 through 1992) at 3 medical centers; 11 episodes of septic arthritis were identified in patients on hemodialysis treatment. Of the 11 episodes, 9 were caused by Staphylococcus aureus; in 8 of 9, the blood cultures were positive for the organism and the infection was monoarticular. Concurrent infection of the dialysis access site occurred in 4 cases. Two patients died (22%). We postulate that repeated skin trauma and contact with health care personnel and facilities result in a high rate of nasal carriage of S aureus and, hence, an increased risk of bacteremia with its attendant complications such as septic arthritis. The use of mupirocin nasal ointment is reported to eradicate or suppress carriage in a high percentage of patients; some studies report that long-term suppressive therapy reduces the frequency of S aureus bacteremia.

Administration, Intranasal↗
PubMed1993

Spinal epidural abscess. Optimizing patient care.

The medical literature regarding spinal epidural abscess has two common threads: reports of poor prognosis and appeals for rapid treatment. Spinal epidural abscess is a difficult diagnosis to make because of its rarity--many physicians will never see a case during their careers. Among all patients admitted to hospitals, the incidence is approximately one to two cases per 10,000. Only increased awareness and swift management of spinal epidural abscess will improve outcome. Our goal through this report is to enhance the recognition and treatment of spinal epidural abscess. We present 28 new cases of spinal epidural abscess, giving special attention to the peculiarities of the disease; we compile and analyze comprehensive data from cases from literature; and finally, we present the results of 16 retrospective personal interviews of infected patients.

Abscess↗
PubMed1992

The relationship of dispositional optimism, daily life stress, and domestic environment to coping methods used by cancer patients.

The relationship of dispositional optimism, daily life stress, and domestic environment to two types of coping methods was examined in a group of 94 cancer patients. As expected, dispositional optimism and domestic environment made significant contributions to the prediction of avoidance coping. Dispositional optimism contributed significantly to the prediction of active-behavioral coping. Specifically, a significant positive relationship was obtained between active-behavioral coping and optimism. A significant positive relationship also was found between avoidance coping and both daily stress and domestic environment. Avoidance coping was negatively related to dispositional optimism. In multivariate analyses, gender and disease-related variables did not make significant contributions to the prediction of coping method. Suggestions for future research were made.

Adaptation, Psychological↗
PubMed1990

The longitudinal use of the Global Assessment Scale in multiple-rater situations.

The Global Assessment Scale was used by multiple clinicians to rate 108 chronically mentally ill outpatients for 18 months. With prior training, high interrater reliability was obtained. Analysis suggests that fluctuations in patients' scores were not attributable to measurement error due to the sequential ratings of multiple clinicians. Moreover, GAS means were inversely correlated with decompensations over the study period. Results indicate that the DMS-III-R recommended use of the GAS in multiple-rater outpatient facilities can be both reliable and clinically useful when supported by thorough staff training.

Adult↗
PubMed1990

Loss of cerebrovascular autoregulation in experimental meningitis in rabbits.

The present study was designed to determine whether cerebrovascular autoregulation is intact in experimental meningitis and to examine the relationship between fluctuations in cerebral blood flow (CBF) and increased intracranial pressure (ICP). Measurements of CBF were determined by the radionuclide microsphere technique in rabbits with experimental Streptococcus pneumoniae meningitis with simultaneous ICP monitoring via an implanted epidural catheter. CBF and ICP measurements were determined at baseline and when mean arterial blood pressure (MABP) was artificially manipulated by either pharmacologic or mechanical means. CBF was pressure passive with MABP through a range of 30-120 torr, and ICP directly correlated with CBF. These findings indicate that autoregulation of the cerebral circulation is lost during bacterial meningitis, resulting in a critical dependency of cerebral perfusion on systemic blood pressure, and that the parallel changes in ICP and in CBF suggest that fluctuations in CBF may influence intracranial hypertension in this disease.

Animals↗
PubMed1989

Evaluation of FCE 22101 in experimental meningitis caused by Escherichia coli and Streptococcus pneumoniae.

FCE 22101 is a new penem antibiotic with a spectrum of activity suggesting a possible role in the empirical treatment of meningitis. It appears to achieve a mean reduction in bacterial titre in CSF comparable with currently accepted agents for both pneumococcal and Escherichia coli meningitis. Its efficacy may, however, be variable. It does not achieve CSF level/MIC ratios as favourable as imipenem for the pathogens studied. Further studies are necessary to determine its role, if any, in this disease.

Animals↗
PubMed1987

Retention of Hispanics in public sector mental health services.

Hispanic underutilization of mental health facilities extends to lowered retention rates among the chronically mentally ill. A theoretical model of retention was developed with four domains of variables: personal traits, accessibility of social support, treatment characteristics, and facility characteristics. Using data collected from CMHC clinical charts in 1983 and 1984, the model was tested using multiple regression and commonality analysis. The model was tenable (R = .59). However, the commonality analysis suggested that most of the unique variance was contributed by the treatment domain. The social support domain made negligible unique contribution. Implications of the model are discussed.

Affective Disorders, Psychotic↗
PubMed1987

Hidden bias in the use of archival data.

Nonresponses in archival data may violate the missing-at-random assumption in ways difficult to detect. Standard methods of comparing sociodemographics of respondents and nonrespondents are inappropriate when the units of analysis are not also the individuals who maintain the archival record. Under these circumstances, the distribution of missing data may be correlated with the dependent variable and traits of the record keepers. This will distort relationships, especially when listwise deletion of missing values is used in multivariate analysis. Data are used from a large clinical chart study of mentally ill patients to demonstrate the process of identifying hidden bias and the implications of such bias.

Archives↗
PubMed1987

Lithium side effects in elderly bipolar outpatients.

A group of 19 geriatric bipolar lithium patients were interviewed in order to assess the incidence, bothersomeness and intensity of medication side effects. The role of subject variables was also examined. Most often reported side effects included excessive thirst, hand tremor, excessive urination and dry mouth. Although many side effects were experienced, these effects were generally tolerated with minimal intensity and bothersomeness. Results indicate that with proper precautions and monitoring, lithium can be safely administered to geriatric bipolar patients.

Age Factors↗
PubMed1986

Cues of disability and treatment continuation of chronic schizophrenics.

Serious questions have arisen concerning the retention of the chronically ill in outpatient community mental health clinics (CMHC). This study tests a model based upon sociological theories of disability and the sick role to explain differential continuation in treatment among schizophrenics. We hypothesized that economic, social and medical cues facilitate a patient's self-definition of disability and contribute to continuation in treatment. Data were collected from the clinical charts of 879 chronic schizophrenic patients at five CMHC's. Hypotheses were tested using OLS multiple regression and logistic regression. Findings indicated level of functioning may be an important explanatory variable. Analysis strongly indicated the efficacy of the medical model in the area of treatment continuation.

Antipsychotic Agents↗
PubMed1984

Pharmacotherapy of the chronic patient: gender and diagnostic factors.

Clinical data from 1752 patients in five, ambulatory community mental health centers were used to test hypotheses about the diagnosis and psychopharmacotherapy of chronic patients. Analysis focused upon the interrelationships among gender, diagnosis, and the number of medications and dosages prescribed. Men and women differed in their age distributions and in the diagnoses received. Women were more often diagnosed with affective disorders than were men. There were also notable interaction effects with ethnicity. There was little evidence of differential drug prescribing practices, although women were somewhat more likely than men to be prescribed anti-psychotics and anti-depressants in the absence of an appropriate diagnosis.

Adolescent↗