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Biomedical subjects

L Rubenstein

Publications and source records attributed to L Rubenstein.

At least 37 records · Page 2Linked to original sources
PubMed1989

An ectopically impacted premolar with a radiolucent defect.

This is a case report of an ectopically impacted, mandibular left second premolar. Radiographically the tooth was observed to have a large radiolucency in the crown. The surgical, orthodontic and restorative management of the case is presented with a brief literature review. The histological report substantiated the previous literature by confirming that the defect was not carious.

Adolescent↗
PubMed1989

The effects of forceps delivery on facial growth.

Postnatal growth of the face is a composite function of genetic and environmental factors. A sudden traumatic insult due to the use of forceps at birth could have long-term effects which could detrimentally influence growth and development. This study examines the development of the skeletal and dental components of forceps vs. non-forceps-delivered patients. The association between delivery methods as related to TMJ problems, bruxism, posterior crossbites, and molar arch width differences was evaluated in 16 forceps-delivered and 29 naturally delivered patients. Results showed no statistically significant difference between delivery method and TMJ problems, posterior crossbites, bruxism, or molar arch width. It was noted that the non-forceps group had a higher incidence of posterior crossbite and narrower molar arch width. The forceps-delivered group had a higher percentage of bruxism and TMJ pain and/or noise. It was also noted that the small sample size may have influenced the statistical relationships.

Adolescent↗
PubMed1987

A molecular model for activation of a 5-hydroxytryptamine receptor.

The extension of a model proposed previously for molecular recognition at a serotonin (5-hydroxytryptamine (5-HT) ) receptor makes possible the formulation of a molecular mechanism of receptor activation. The activation mechanism proposed here is based on the changes induced in the drug and in a model receptor by the interaction mimicking the formation of a drug-receptor complex. This mechanism was simulated by quantum mechanical calculations of molecular interactions between 5-HT and a model for a receptor represented by an imidazolium-ammonia complex that serves as a proton transfer model (PTM). The movement of the proton in the PTM is promoted by the interaction with 5-HT, suggesting a process by which 5-HT can trigger the activation of the receptor. The elements of the activation mechanism revealed by the results of the simulation are: (a) the electrostatic alignment between the PTM and 5-HT, which guides the recognition of 5-HT by the PTM; (b) the contraction of the distance between the hydrogen bonded components of the PTM, induced by the interaction of 5-HT with the PTM, which leads to a decrease in the barrier to proton transfer in the PTM; (c) an additional decrease of the barrier to proton transfer produced by the negative electrostatic potential of 5-HT, which stabilizes the transition state; and (d) the increased preference for product over reactant in the interaction complex between 5-HT and the PTM, which constitutes a driving force for the proton transfer process. According to this model, compounds that activate the 5-HT receptor should bind in a mode that induces the changes described above in the PTM and thus triggers the proton transfer.

Calorimetry↗
PubMed1985

A molecular theory of recognition and activation at a 5-HT receptor based on a quantum chemical approach to structure activity relationships.

The study of structure activity relationships (SAR) is based on the delineation of the causal relationships between the properties of molecules and the observed responses evoked by the interaction of these molecules with biological systems. The methods of theoretical and quantum chemistry describe accurately the molecular properties that are determined by molecular structure and provide a rigorous link between structure and activity. We study the molecular events in the pharmacological mechanism of drugs interacting with the receptor of 5-hydroxytryptamine (5-HT, serotonin) by defining the elements of recognition and by analyzing the changes induced in a molecular model for the receptor. These steps define the relationship between the properties of the drugs and their ability to be recognized and cause the activation of the receptors. Consequently, our quantum chemical studies of drug-receptor interactions explain the selectivity of receptors and the molecular determinants for agonism and antagonism on the 5-HT receptor.

Imidazoles↗
PubMed1978

Combined modality therapy for stage IIIMO non-oat cell bronchogenic carcinoma.

Thirty-nine patients with stage IIIMO non-cell bronchogenic carcinoma (NOBC) were treated with combined modality therapy: radiation therapy and chemotherapy with cyclophosphamide, adriamycin, methotrexate, and procarbazine. The median survival for all patients treated was 9.6 months compared to 6.4 months for historical controls (P = 0.015). Patients who responded to the treatment program had a significantly longer survival (median, 15.2 months) compared to nonresponders and historical controls (P less than 0.005). It is concluded that combined modality therapy is moderately effective therapy in stage IIIMO NOBC.

Carcinoma, Bronchogenic↗
PubMed1977

Quality-of-care assessment by process and outcome scoring. Use of weighted algorithmic assessment criteria for evaluation of emergency room care of women with symptoms of urinary tract infection.

Weighted process criteria based on chart review using an algorithmic method, and weighted outcome criteria based on a telephone interview with the patient, were used to assess the quality of emergency room care of women with symptoms of acute urinary tract infection. Outcomes at a municipal hospital were significantly better than those at an affiliated voluntary hospital. Process and outcome scores were positively correlated at both hospitals; the data suggest, but do not themselves adequately test, the hypothesis that the correlation is curvilinear and that there is a threshold process score below which a poor outcome is extremely likely. Our findings suggest that weighted algorithmic assessment criteria are a useful method for quality assessment and are consistent with the testable hypothesis that the greatest improvements in outcome may result from raising the quality of care from a poor to an adequate level rather than from an adequate to an optimal level.

Adult↗
PubMed1976

Cyclophosphamide, adriamycin, methotrexate, and procarbazine (CAMP)--effective four-drug combination chemotherapy for metastatic non-oat cell bronchogenic carcinoma.

Twenty-three patients with metastatic non-oat cell bronchogenic carcinoma (MNOBC) were treated with cyclophosphamide, adriamycin, methotrexate, and procarbazine (CAMP) after radiation therapy. Objective responses were seen in 11 of 23 patients (48%) with a projected median survival time of 12.5 months for responding patients and patients with stable disease. Lung, liver, and cutaneous sites of involvement proved to be highly responsive; bone involvement was less responsive. CAMP is an effective combination in the treatment of MNOBC and its use in patients with less advanced disease should be explored.

Adenocarcinoma↗
PubMed1975

Determinants of the choice of rural practice: a study of Yugoslav general practitioners.

A questionnaire study of Yugoslav general practitioners was undertaken to document reasons for the unpopularity of rural practice and to characterize better the GPs who do choose rural practice. Responses indicated that rural GPs were significantly more overworked, had less opportunity for continuing education, had poorer medical facilities, and had less adequate schools for their children than urban GPs. On the other hand, rural work was felt to be more interesting and to provide closer contact with patients. GPs who were happy in rural practice were more likely to have urban backgrounds, to have planned to be rural physicians before entering medical school, and to have undergone GP specialization training than were other GPs in the sample. Relative importances attributed to the various practice location determinants are noted. Possible applications of the study in alleviating rural doctor shortages are discussed.

Attitude of Health Personnel↗
PubMedDate not supplied

The ambulatory care of HIV-infected persons: a survey of physician practice patterns.

OBJECTIVE: To describe the use of various counseling practices, examinations, and laboratory tests used by general internists in the primary care of HIV-infected persons. DESIGN: Mailed questionnaire survey. SUBJECTS: Random sampling of members of the Society of General Internal Medicine. RESULTS: Based on a 64% response rate (131/205), there are many areas of physician agreement in the ambulatory care of HIV-infected persons. Greatest physician consensus was seen in the use of viral serologic testing, vaccinations, and Pap tests. Most (70-80%) primary care physicians do not use surrogate markers such as beta 2-microglobulin and p24 antigen to follow disease progression; instead, they rely mostly on CD4 lymphocyte counts. Sixty percent of physicians continue to order CD4 lymphocyte counts when a baseline count is under 200 cells/mm3. All studies are ordered more frequently for patients with more advanced disease. As a group, those physicians following the largest number of patients do not manage patients significantly differently from the less HIV-experienced physicians. CONCLUSIONS: Despite some variation, there is substantial consensus on the "routine" management of HIV-infected persons. Clinical guidelines would be one mechanism for defining appropriate care of HIV-infected patients. The majority judgments of the practitioners studied here could be one component among various sources of information used by expert panels to define guidelines except where studies clearly indicate a different and more effective approach. Such incorporation might increase guideline acceptance by practicing clinicians.

Adult↗
PubMedDate not supplied

Evaluating humanistic attributes of internal medicine residents.

OBJECTIVE: Methods of assessing humanism in internal medicine residents have not been completely designed or evaluated. This study used patient satisfaction as a measure of humanism, and assessed the validity of using faculty physicians to evaluate residents' humanistic behavior. Residents' ability to assess themselves was also evaluated. SETTING: A university-affiliated internal medicine training program. SUBJECTS: Forty-seven internal medicine residents were evaluated by patients, faculty, and themselves. DESIGN: Faculty physicians were given standard faculty evaluation and patient satisfaction forms, and were asked to evaluate residents. These evaluations were compared with the patients' responses on the same satisfaction forms. Residents performed self-assessment using identical forms; these responses were compared with those of the faculty and patients. RESULTS: There was no correlation between patients' responses and those of the faculty or residents. There was a significant inverse correlation between resident and faculty responses, especially for the female residents (r = 0.71). CONCLUSION: These findings suggest the need for further study of the evaluation process, including what factors influence individuals to respond as they do. It appears that the use of one rating group is not sufficient to achieve an accurate assessment of residents' humanistic skills. The present status of the process of evaluating humanism is discussed.

Adolescent↗