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Biomedical subjects

R Feldman

Publications and source records attributed to R Feldman.

At least 145 records · Page 8Linked to original sources
PubMed1989

The role of health practices in HMO selection bias: a confirmatory study.

This research examines the relation between employees' health practices and health plan selection. A previous study, limited to one firm, showed that employees choosing a health maintenance organization (HMO) and a fee-for-service (FFS) plan had similar health practices. We extend this inquiry to 17 Minneapolis employees, all of whom offer at least one FFS plan and one or more of the 6 Twin Cities HMOs. Health practices were measured by cigarette smoking, heavy drinking (or abstinence from drinking), use of seat belts, and exercise. We estimated health plan choice equations that show that employees with poor health practices do not systematically prefer FFS plans compared with independent practice associations (IPAs). Nor do they select FFS or IPA plans compared with HMOs on the basis of health habits. We suggest that HMOs do not gain long-term cost advantages by enrolling employees with favorable health practices.

Choice Behavior↗
PubMed1989

"Angiography" by magnetic resonance imaging: detailed vascular anatomy without ionizing radiation or contrast media.

Using software to transform magnetic resonance imaging (MRI) tomographic data into three-dimensional projections, we have produced "angiograms" of the abdominal aorta in 18 patients with occlusive (15) and aneurysmal (3) disease. This information may be displayed to demonstrate flow, cross-sectional diameter, or aortic surface anatomy. To test the accuracy of the MRI studies, we compared them at selected points with the transected aorta and with routine aortograms. Relative cross-sectional diameter estimated by MRI was within 15% of measured aortic diameter in 14 of the 18 vessels and enabled correct detection of thrombus in 16. We conclude that MRI may accurately image the diseased abdominal aortic wall. In addition, an angiographic display format may aid in the interpretation of these studies. Although MRI is not likely to replace aortography, it could be used adjunctively to define aortic wall thickness and the presence of thrombus.

Aged↗
PubMed1989

Health maintenance organizations: the beginning or the end?

This article describes the changes taking place in a mature HMO market that has been identified as a bellwether HMO community, the Minneapolis-St. Paul metropolitan area. We describe how this market--previously characterized by traditional HMOs and traditional fee-for-service plans--has been transformed within the past five years into a market with a variety of plans competing on the dimensions of premiums, provider choice, and coverage. Among the most significant changes are the evolution of the local Blue Cross and Blue Shield plan into a form resembling an individual practice arrangement (IPA) with broad coverage and broad provider choice, and the appearance of preferred provider plans sponsored by the HMOs. We suggest that such changes have blurred the distinction between health plan types, making traditional plan designations no longer valid for either health policy analysis or health services research. For example, studies contrasting the performance of HMOs and fee-for-service plans should concentrate instead on the various dimensions of these plans, such as coverage and openness of provider choice. The article is intended to stimulate discussion and to suggest a new framework for describing health plan competition.

Fees, Medical↗
PubMed1988

Serial studies of the IgG subclass and functional affinity of DNA antibodies in systemic lupus erythematosus.

The functional affinity and IgG subclass of antibodies to ss and dsDNA were measured by ELISA in five serial samples from 41 patients with systemic lupus erythematosus (SLE) who were divided into relatively homogeneous disease subgroups. Anti-dsDNA antibodies were restricted to IgG1 and IgG3 in renal disease and levels increased with disease severity. Functional affinity of IgG1 and IgG3 anti-dsDNA fell in patients with severe renal disease, suggesting that the high affinity antibody population lost from the serum was localizing in the kidneys. IgG2 anti-dsDNA were found in patients with joint and skin disease alone and in the thrombotic/spontaneous abortion subgroup. IgG2 antibody levels did not correlate with disease severity but did correlate with the presence of antibodies to Klebsiella K30 and may have represented a cross-reactive antibody population.

Antibodies, Antinuclear↗
PubMed1988

A comparison of autoantibodies and common DNA antibody idiotypes in SLE patients and their spouses.

In order to determine whether environmental influence per se might influence autoantibody production, sera from the spouses of 20 SLE patients were examined. No antibodies to cardiolipin, poly (ADP-ribose), or ENA were detected and none had detectable rheumatoid factor. One weakly positive ANA reaction was noted, one had anti-DNA antibodies (by RIA and ELISA) and in two sera the common DNA antibody idiotype 16/6 was found. The idiotype was not, however, present on either anti-DNA or anti-K30 antibodies. Although long-term analyses are required, it is evident that sharing the same environment with patients who commonly express a wide range of autoantibodies and common idiotypes rarely leads to their expression in non-autoimmune subjects.

Antibodies, Antinuclear↗
PubMed1988

Competition among physicians, revisited.

Ten years ago we developed a model of demand inducement in the physician services market and explored the properties of that model. We found that predictions concerning physicians' prices, workloads, and income were ambiguous and in many cases were consistent with those derived from a standard monopoly pricing model. Spurred in part by our work, numerous empirical studies of the demand inducement model have been conducted. These studies found little evidence of demand inducement for primary care physician services. Demand inducement may exist in the market for surgical services, but its extent is less than previously estimated. We disagree with those who say that physicians generate demand to avoid price controls and that national health care spending is proportional to the number of physicians; the evidence does not support these arguments. Substantial uncertainty may surround the physician's choice of diagnosis and treatment mode. However, this does not imply a breakdown of the agency relationship. In this paper we extend our earlier model of demand inducement to include variations in the quantity of services (which was previously assumed to be less than socially ideal). Using the model, we conclude that the major objection to government price setting is not that physicians will get around the controls by inducing demand; rather, price controls result in a quantity and quality of physicians' services that is not ideal and may be inferior to those provided in an unregulated monopoly.

Canada↗
PubMed1988

[4 cases of poisoning with the extract of yew (Taxus baccata) needles].

Four prisoners drank a decoction of yew (Taxus baccata) needles containing the toxic alkaloid taxine++ B. Two died in prison (one in the cell, the other shortly after admission to prison hospital, death was caused in both cases by cardiac arrest). Two other prisoners were admitted to the Warsaw Poisons Control Centre. One of them was in deep coma, with severe ventricular arrhythmias and had several episodes of ventricular fibrillation controlled with defibrillatory procedures. After an initial improvement (return of consciousness) his general condition deteriorated suddenly, he lost consciousness again, his circulation stopped and he died on the fourth day of hospitalization. The other patient drank a much smaller amount of the decoction. He was conscious, had bradycardia requiring transient endocavitary pacemaking, and had mild ventricular arrhythmia. He left the hospital in a very good condition after ten days of treatment. In both these cases long-standing excessive diuresis and corresponding considerable hypokalemia were observed. A synergism of the toxic effects of taxine++ B, digitalis glycosides and hypokalemia is considered very likely. In both cases atropine was effective for a short time in the control of bradycardia.

Alkaloids↗
PubMed1987

A study of antipolynucleotide antibodies, anti-Klebsiella (K30) antibodies and anti-DNA antibody idiotypes in ankylosing spondylitis.

Recent studies have indicated that both ankylosing spondylitis and the anti-DNA antibodies found in systemic lupus erythematosus may be related to Klebsiella surface antigens. In order to explore these possible relationships further, the sera of 24 patients with ankylosing spondylitis (AS), and 20 controls, have been examined for binding to a wide range of antipolynucleotide antibodies, antibodies binding to the Klebsiella pneumoniae polysaccharide K30 and two DNA antibody idiotypes designated 16/6 and 134. We report that although 21% of the AS patients had IgG ssDNA antibodies it is evident that the aetiopathogenesis of this disease is not through the mechanism of autoantibodies or the common DNA antibody idiotypes tested.

Antibodies, Antinuclear↗
PubMed1987

Internal pudendal pseudoaneurysm complicating an ischial pressure sore.

A 23-year-old paraplegic patient experienced two episodes of substantial hemorrhage from an ischial pressure sore. Computed tomography showed that the wound extended into the pelvis and retroperitoneum, and arteriography demonstrated a pseudoaneurysm of the internal pudendal artery. The artery was selectively embolized, permitting debridement and flap coverage uncomplicated by bleeding. Bleeding from a pelvic extension of a pressure sore can be a catastrophic combination of distorted anatomy and relatively inaccessible vessels. As in hemorrhagic complications of pelvic trauma, tumors, and radiation, arteriography and transcatheter embolization can localize and control the source of bleeding.

Adult↗
PubMed1987

The sera of patients with Klebsiella infections contain a common anti-DNA idiotype (16/6) Id and anti-polynucleotide activity.

In view of recent reports linking Klebsiella pneumoniae with autoimmunity, we have examined the sera of 52 patients with urinary tract infection or septicaemia from this Gram-negative pathogen, for the presence of antibodies to DNA, polynucleotides, cardiolipin and a common anti-DNA idiotype 16/6. Up to 27% of these patients had anti-polynucleotide antibodies detectable, and in 37% the 16/6 idiotype was found. Absorption of the sera of two patients, with no DNA binding, against the Klebsiella polysaccharide K-30 induced a significant fall in both their anti-K30 antibody and 16/6 idiotype levels. Among 52 patients with other Gram negative infections a maximum of 17% and 19% respectively, had anti-DNA antibodies and the 16/6 idiotype present in their serum. In 37 normal controls, the rate of antibody and idiotype detection was 5% or less. The presence of autoantibodies in the serum of patients with Klebsiella infections may be the result of non-specific stimulation due to bacterial polyclonal activation. However, there might also be a specific stimulus triggered by idiotypic cross-reaction between autoantibodies and anti-Klebsiella antibodies.

Adult↗
PubMed1987

[Evaluation of esophageal involvement by pHmetry in patients with progressive systemic sclerosis].

The authors studied 16 patients with progressive systemic sclerosis to whom it was performed ph-metry, acid clearance and oesophageal electromanometry, compared the results with a control group of 20 patients. The oesophageal basal ph showed significative difference (p greater than 0.001) at the same as acid clearance (p greater than 0.01). It was not found correlation between the manometric alterations and acid clearance changes. (F 5%); at same as the last one and the clinical evolution period. (r = 0.16). Gastroesophageal reflux was positive in all the patients. The authors considered that intra-esophageal ph-metry and acid clearance was two methods with high sensibility to evaluate the oesophageal deterioration in systemic disease.

Adult↗