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Biomedical subjects

A Rubin

Publications and source records attributed to A Rubin.

At least 19 recordsLinked to original sources
PubMed2006

Radioactive materials in biosolids: dose modeling.

The Interagency Steering Committee on Radiation Standards (ISCORS) has recently completed a study of the occurrence within the United States of radioactive materials in sewage sludge and sewage incineration ash. One component of that effort was an examination of the possible transport of radioactivity from sludge into the local environment and the subsequent exposure of humans. A stochastic environmental pathway model was applied separately to seven hypothetical, generic sludge-release scenarios, leading to the creation of seven tables of Dose-to-Source Ratios (DSR), which can be used in translating from specific activity in sludge into dose to an individual. These DSR values were then combined with the results of an ISCORS survey of sludge and ash at more than 300 publicly owned treatment works, to explore the potential for radiation exposure of sludge workers and members of the public. This paper provides a brief overview of the pathway modeling methodology employed in the exposure and dose assessments and discusses technical aspects of the results obtained.

Environmental Monitoring↗
PubMed2005

Ionized magnesium levels and the ratio of ionized calcium to magnesium in asthma patients before and after treatment with magnesium.

OBJECTIVE: Prior studies have been equivocal about the efficacy of magnesium therapy in acute asthma exacerbations. We hypothesize that pretreatment ionized magnesium (Mg(2+)) levels and/or the ratio of ionized calcium to ionized magnesium (Ca(2+)/Mg(2+)) may have been confounding variables in these previous studies. Here, we report on the incidence of abnormal divalent ion levels in our asthma population. MATERIAL AND METHODS: The study was designed as a randomized, double-blind, placebo-controlled trial of intravenous magnesium. Inclusion criteria were: age >18 years, percentage predicted forced expiratory volume (FEV(1)) <75 % after an initial beta-agonist. African-American patients (AA) at an urban university hospital were randomized to 2 g IV Mg or placebo. Mg(2+) and Ca(2+)/Mg(2+) levels were measured pre- and post-infusion. Data were reported as means+/-SD. Student's t-test and Fisher's exact test were used where appropriate (alpha = 0.05, two tailed). RESULTS: Fifty-five AA patients (mean age of 42.7 years+/-15.6 years, range 18-75 years) were studied. A significantly (p<0.05) lower level of Mg(2+) was found in asthma (AS) patients compared with that in the AA group, by 0.03 mmol/L (95 % CI, 0.007-0.053 mmol/L). The AS group had a mean increase in Ca(2+)/Mg(2+) ratios over the AA group, of 0.27 (95 % CI, 0.16-0.38); 100 % of patients with abnormal divalent ion levels were corrected with IV magnesium. CONCLUSIONS: We identified a subgroup of asthmatic patients with significant abnormalities in their divalent ion concentrations, which was corrected with IV magnesium.

Adolescent↗
PubMed2005

Error cells for spherical powers in symmetric dioptric power space.

PURPOSE: : The purpose of this article is to analyze the geometry and examine the implications of the error cells of purely spherical powers in symmetric dioptric power space. METHODS: : In the context of spherocylindrical data spherical data typically implies a cylindrical component that is less than some particular amount (often 0.125 D) in magnitude. This error or uncertainty in cylinder is over and above the error in sphere itself. The two components of error are used to define the error cells in symmetric dioptric power space. RESULTS: : Error cells of spherical powers are constructed and presented as stereopairs. They are also shown in relation to error cells of powers in general. CONCLUSIONS: : An understanding of error cells can help the researcher avoid pitfalls in the analysis of spherocylindrical data. Perhaps surprisingly, the error cells of spherical powers are not invariant under spherocylindrical transposition.

Humans↗
PubMed2001

Patient placement criteria and their relation to access to appropriate level of care and engagement in alcoholism treatment.

Patient placement criteria (PPC) facilitate treatment matching through detailed, standardized assessment of patients' needs. This process affords the alcoholism treatment field an opportunity to address issues that influence access to appropriate level of care by highlighting these issues during the assessment. The American Society of Addiction Medicine Patient Placement Criteria can integrate assessment of social and environmental, institutional and patient issues that affect access to appropriate care and treatment engagement. They can ultimately improve access through an iterative approach: developing a broad consensus on guidelines based on research evidence and expert clinical opinion, making criteria clear and easy to use both for assessment and for teaching purposes, addressing the needs of special populations, and testing and improving the validity of decision rules to achieve optimal access and treatment engagement. Early evidence suggests that PPC are promising but there is much about them that remains to be tested and improved.

Alcoholism↗
PubMed2001

Relaxation of variable chlorophyll fluorescence after illumination of dark-adapted barley leaves as influenced by the redox states of electron carriers.

Kinetics of the dark relaxation of variable chlorophyll fluorescence, Fv, were studied after brief illumination of dark-adapted barley leaves in order to understand the rapid reversibility of pulse-induced fluorescence increases, which is observed even when fast linear electron transport to an external electron acceptor is not possible. Four kinetically distinct components were observed which reveal complexity in the oxidation of the reduced primary quinone acceptor of Photosystem II, Q (A) (-) : the slowest component accounted for 4-5% of maximal Fv and had a life-time of several seconds. It is suggested to represent a minor population of inactive Photosystem II centers. The other three components displayed first-order kinetics with half-time of 6-8 ms ('fast' component), 60-80 ms ('middle' component) and 650-680 ms ('slow' component). The fast component dominated Fv when methyl viologen or far-red light accelerated oxidation of plastohydroquinone. It shows rapid oxidation of Q (A) (-) during electron flow to plastoquinone commensurate with maximum linear electron flow through the electron transport chain. The other two components were observed under conditions of restricted electron flow and excessive reduction of electron carriers. Unexpectedly, the slow component, which is interpreted to reflect the recombination between Q (A) (-) and an intermediate on the oxidizing side of Photosystem II, saturated already at low irradiances of actinic light when plastoquinone was not yet strongly reduced suggesting that dark-adaptation of leaves results not only in the loss of activity of light-regulated enzymes of the carbon cycle but affects also electron flow from Q(A) (-) to plastoquinone. KCN poisoning or high temperature treatment of leaves produced a nonexponential pattern of slow Fv relaxation. This effect was largely (heat treatment) or even completely (KCN) abolished by far-red light.

Journal Article↗
PubMed2001

Sertraline treatment of panic disorder: results of a long-term study.

OBJECTIVE: To investigate the long-term efficacy, prevention of relapse and safety of sertraline in the treatment of panic disorder. METHOD: This study consisted of 52 weeks of open-label sertraline treatment (n=398) followed by a 28 weeks of a double-blind, placebo-controlled discontinuation trial (n=183). RESULTS: Ninety-three patients were randomized to sertraline and 90 were randomized to placebo. Discontinuation due to insufficient clinical response occurred in 23.6% of placebo-treated patients and 12.0% of sertraline-treated patients (log-rank test, P=0.040). Thirty-three per cent of placebo-treated patients had an exacerbation of panic symptomatology, versus 13% of sertraline-treated patients (log-rank test, P=0.005). Abrupt cessation of sertraline resulted in dizziness (4.3% sertraline vs. 16.9% placebo; P=0.007) and insomnia (4.3% sertraline vs. 15.7% placebo; P=0.013) occurring at significantly higher rates. CONCLUSION: Long-term sertraline treatment was effective in preventing relapse of panic disorder, well tolerated and associated with minimal discontinuation symptoms.

Adult↗
PubMed2001

Mitoxantrone and paclitaxel combination chemotherapy in metastatic breast cancer.

This study evaluated mitoxantrone and paclitaxel combination chemotherapy in the treatment of patients with metastatic breast cancer. Thirty-seven patients who had developed progressive disease after prior chemotherapy were treated with mitoxantrone (14 mg/m2) and paclitaxel (150 mg/m2) every 21 days for a maximum of six cycles. The most frequent grade 3 or 4 nonhematological toxicities were fever and nausea. Grade 4 neutropenia occurred in 71% of patients. Cardiotoxicity occurred in 2 patients, both of whom had previously received doxorubicin. Objective response was achieved in 35% of patients (5% complete response and 30% partial response) and 41% had stable disease. Median time to disease progression and median survival were 6 and 12 months, respectively. The percent of patients with an objective response was not different for those who had received prior doxorubicin or had chemotherapy in the preceding 6 months. This regimen appears to be effective and well tolerated as salvage therapy and merits further evaluation.

Adult↗
PubMed2001

Closed surfaces of constant visual acuity in symmetric dioptric power space.

This paper demonstrates a multivariate approach to understanding the complicated relations of visual acuity to refractive state or ametropia. Other approaches, as previously used, included graphical representations of lines or profiles of iso-oxyopia (Peters, 1961). But one limitation of Peters' method is that cylinder axis was ignored. However, here the relationship between visual acuity and refractive power will be represented by estimated closed surfaces of constant visual acuity in symmetric dioptric power space. At or near the common center (of several closed surfaces, for example) is the refractive compensation. Coming outwards from such a center, the visual acuity drops in all directions in the space. The primary purpose of this paper was to present estimated closed surfaces of constant visual acuity for several eyes. Various procedures were performed on several subjects including measurement of iris aperture diameter, subjective refraction, and autorefraction. Thereafter, an automated phoropter and either Jackson cross-cylinders or spheres were used to influence dioptric blur or defocus in the subjects. The visual stimulus was a computer-generated nondirectional or meridionally independent letter O. Ovoidal surfaces fit the measurements obtained (with Jackson cross-cylinders and spheres) better than ellipsoidal surfaces. The cross-section, in symmetric dioptric power space, at powers with the same nearest equivalent sphere as the refractive compensation is elliptical in many cases and reflects a dependence of visual acuity on cylinder axis. The surfaces differ when powers are changed so that one is moving away from (decompensation surfaces) or toward (accompensation surfaces) the refractive compensation. The multivariate and graphical methods used in this paper probably have implications for the direction of future research in a number of areas involving measures of vision function such as autorefraction, retinoscopy, subjective refraction, and visual acuity.

Accommodation, Ocular↗
PubMed2001

Mitoxantrone and fludarabine in the treatment of patients with non-Hodgkin's lymphoma failing primary therapy with a doxorubicinor mitoxantrone-containing regimen.

Patients with recurrent lymphoma of any grade were treated with mitoxantrone (12 mg/m2 given intravenously (IV) over 15-30 minutes on day 1) followed by fludarabine at a dose of (25 mg/m 2 given IV over 30 minutes on days 1-3) every 28 days fludarabine at a dose of (25 mg/m2 given IV over 30 minutes on days 1-3) every 28 days. All patients had failed one prior chemotherapy regimen that contained either doxorubicin or mitoxantrone, total dose not exceeding 350 mg/m2 doxorubicin or 80 mg/m2 mitoxantrone. mitoxantrone. Thirty one patients (22 with intermediate- or high-grade and 9 with low-grade NHL) were enrolled. Median age was 63 years (range: 21 to 87). The objective response rate for patients with intermediate/high-grade NHL was 55% (27% with CR) and 89% (56% with CR) for patients with low-grade NHL. Median time to disease progression was 5.1 months for patients with intermediate/high-grade NHL and 10.8 months for patients with low-grade NHL. Median time to death for patients with intermediate/high-grade disease was 11.4 months. Median time to death for patients with low-grade NHL was not calculable as only one death (due to respiratory failure) occurred in this group 6.5 months after study start. The regimen was well tolerated. Grade 3/4 neutropenia was reported in 80% (24 of 30) of patients and Grade 3/4 thrombocytopenia in 19% (6 of 31) of patients. Nine hospitalizations for adverse events (primarily fever and neutropenia) occurred among eight patients, all with intermediate/high-grade NHL, during a total of 118 cycles of therapy. Further studies of this combination regimen in patients with intermediate/high-grade NHL and studies combined with monoclonal antibodies in low-grade NHL are warranted.

Adult↗
PubMed2001

Improving alcoholism treatment across the spectrum of services.

This article represents the proceedings of a symposium at the 2000 RSA Meeting in Denver, Colorado. The chair was Michael E. Hilton. The presentations were (1) The effects of brief advice and motivational enhancement on alcohol use and related variables in primary care, by Stephen A. Maisto, Joseph Conigliaro, Melissa McNiel, Kevin Kraemer, Mary E. Kelley, and Rosemarie Conigliaro; (2) Enhanced linkage of alcohol dependent persons to primary medical care: A randomized controlled trial of a multidisciplinary health evaluation in a detoxification unit, by Jeffrey H. Samet, Mary Jo Larson, Jacqueline Savetsky, Michael Winter, Lisa M. Sullivan, and Richard Saitz; (3) Cost-effectiveness of day hospital versus traditional alcohol and drug outpatient treatment in a health maintenance organization: Randomized and self-selected samples, by Constance Weisner, Jennifer Mertens, Sujaya Parthasarathy, Charles Moore, Enid Hunkeler, Teh-Wei Hu, and Joe Selby; and (4) Case monitoring for alcoholics: One year clinical and health cost effects, by Robert L. Stout, William Zywiak, Amy Rubin, William Zwick, Mary Jo Larson, and Don Shepard.

Alcoholism↗
PubMed2001

New trends in regional anaesthesia.

In this review, some of the newer developments in regional anaesthesia (RA) are discussed. The relationship between paraesthesiae and nerve stimulator responses has been shown to be unclear, and sometimes at a needle tip location where a paraesthesia is found, there is no response to the nerve stimulator. It is recommended to use whichever end point is found first. The debate as to the safety of RA in anaesthetised patients remains unresolved and strong opinions are often based on individual case reports. The training and skill of the anaesthetist still appears to be a more important factor. The problems of RA and impaired coagulation are well understood and guidelines are in place in many countries. The value of neuraxial blocks for postoperative pain management is well established and the increasing use of peripheral nerve blocks often using continuous methods is to be encouraged. The use of PCA for blocks as well as intravenously and the extension of the use of RA into the home are important developments. The beneficial effects of RA on postoperative morbidity and mortality are becoming clearer, and the introduction of the two new local anaesthetic agents, ropivacaine and levobupivacaine have improved safety. There has, however, been very slow progress in the development of long awaited ultralong acting local anaesthetics or in the introduction of slow release formulations.

Anesthesia, Conduction↗
PubMed2000

Prevalence of Müllerian duct anomalies detected at ultrasound.

The true prevalence of müllerian duct abnormalities is not well established. We used standard ultrasound examinations to establish the prevalence of müllerian duct abnormalities in girls and women who were evaluated for reasons unrelated to the presence of uterine anomalies. Prospective ultrasound examinations for nonobstetric indications in 2,065 consecutive girls and women (aged 8-93) showed that 8 had anomalies, including bicornuate uterus, septate uterus, and double uterus. In this first attempt to determine the prevalence of uterine anomalies in the general population, using noninvasive methodology, the rate of anomalies was 3.87 per 1,000 women (exact 95% confidence interval: 1.67-7.62), or approximately 1 in 250 women. This prevalence estimate may be greater than the true rate if selection biases are strong, or less than the true prevalence if ultrasound detection rates are low. As a first attempt to establish the prevalence by pelvic ultrasound in a consecutive series, these data may serve as a baseline estimate.

Adolescent↗