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Biomedical subjects

D Altman

Publications and source records attributed to D Altman.

At least 55 records · Page 3Linked to original sources
PubMed1988

Regulation of an idiotype+ B cell lymphoma. Effects of antigen and anti-idiotopic antibodies on proliferation and Ig secretion.

The B cell surface Ig molecule plays an important regulatory role in delivering inductive/tolerogenic signals to the cell. In this paper, the effect of Ag and anti-idiotopic antibodies on the in vitro proliferation and Ig secretion of a B cell tumor was studied. The tumor (BCL1), which had been transfected with the TEPC-15 VH and VL Ig genes, expresses surface Ig and secretes antibody that binds the hapten phosphorylcholine. We found that Ag (C polysaccharide and phosphorylcholine carrier Ag) and two different anti-idiotopic antibodies, in the absence of T cells, all inhibited the proliferation of the T15+ transfectant cell line. The anti-idiotopic antibodies, but not Ag, also inhibited the secretion of T15 Ig by this cell line, suggesting different functional roles for Ag vs anti-Id in the regulation of B cell inactivation. The inhibition of secretion and proliferation appears to be cell cycle phase related. In addition, mouse rIL-4 could override the inhibition of proliferation induced in these studies. These phenomena, demonstrating that binding of surface Ig can result in the transduction of negative growth signals to a B cell tumor, can be viewed as a manifestation of immunologic tolerance. These findings collectively demonstrate that Ag and anti-Id mediate different signals to B cells via interaction with the surface Ig. Because of the monoclonal nature of the T15 transfectant and the anti-idiotypic antibodies, this system can be used to investigate the underlying molecular reactions involved in the B cell response and induction of tolerance.

Animals↗
PubMed1986

An endonuclease from Chlamydomonas reinhardtii that cleaves the sequence TATA.

An endodeoxyribonuclease, designated CreI, was purified 16,000-fold from zygotes of the eukaryote Chlamydomonas reinhardtii. CreI preferentially attacks the sequence TATA producing double strand breaks with 3'-phosphomonoester and 5'-hydroxyl termini. The endonuclease has an Mr = 27,000 and requires Ca2+ at pH 7.5 for optimal activity.

Base Sequence↗
PubMed1986

An evaluation of the Avionics Pressurometer III 1978 at home and in hospital.

The Avionics Pressurometer III is the only noninvasive indirect ambulatory blood pressure system which provides 24-h blood pressure measurements, but it has been subjected to limited evaluation. We report a critical evaluation comparing it to simultaneous intra-arterial blood pressures both at home and at hospital as well as during standardized exercise. Comparisons with simultaneous indirect methods were also made. Twenty-two hypertensives undergoing intra-arterial ambulatory blood pressure monitoring wore the two recorders for one day. The mean difference (standard deviation SD) for intra-arterial blood pressure--Avionics blood pressure was 2 (SD 8.6)/-14 (SD 10.3) mmHg at home and -3 (SD 15.4)/-11 (SD 12.3) mmHg at hospital. At the end of exercise the figures for the same comparison were -7 (SD 16)/0 (SD 15.6) mmHg. In general the agreement between intra-arterial and Avionics pressurometer recordings was closer for systolic than for diastolic blood pressures but there was wide variation for individuals as shown by the standard deviations about the mean difference. We did not use the recorder at night as patients complained that the noise kept them awake and so night-time blood pressures were not attainable. We do not think the recorder performed satisfactorily during physical exertion, and in view of its expense, this recorder is of limited potential value in supplying accurate information.

Adult↗
PubMed1985

Biliary sclerosis in patients receiving hepatic arterial infusions of floxuridine.

High response rates have been reported with hepatic intra-arterial infusions of floxuridine in patients having colorectal carcinoma metastatic to the liver. The major toxicity of this therapy has been described as "chemical hepatitis." In a randomized trial of intravenous v intra-arterial floxuridine, we observed that all 35 patients receiving intra-arterial therapy developed significant increases in alkaline phosphatase and, in some cases, serum glutamic oxaloacetic transminase and/or bilirubin. Seven patients receiving intra-arterial therapy were studied with cholangiography which, in all cases, demonstrated sclerosis of the intrahepatic and/or extrahepatic bile ducts. In addition, liver biopsies showed cholestasis and pericholangitis with minimal hepatocyte damage. These findings suggest that "biliary sclerosis" rather than "chemical hepatitis" is the predominant toxicity associated with hepatic intra-arterial infusions of floxuridine.

Aged↗
PubMed1983

Health care for the poor.

In the 1980s the convergence of a number of factors is causing government at all levels, industry, and labor to plan or initiate major reductions in health spending. Important among these are rising health care costs, a troubled national economy, mounting federal deficits and state revenue shortfalls, and the philosophical course and domestic policy of the Reagan administration. In this context government has been rethinking its capacity to finance health services for the poor, and new and sometimes controversial arrangements for delivering these services are being developed. The dilemma government officials face now is how to cut costs while still assuring that quality medical services are available. This article focuses on what these new policy developments and arrangements are and whether the significant gains in access and in health achieved over the past 20 years will be sustained. Because truly sweeping reforms are unlikely, whether government will maintain earlier commitments and established arrangements for financing and delivering health services to the poor will be worked out piecemeal over the next several years.

Health Expenditures↗
PubMed1982

Predicting rural health care utilization with archival data.

This study explored the usefulness of archival data in predicting rural health care utilization. A regression model was used to see how well observed utilization for local populations could be predicted by calculating expected values in advance from age- and sex-specific national rates applied to local age and sex profiles. Although the correlation between observed and expected utilization was reasonably high (r = 0.92), an attempt was then made to improve prediction by considering other data that do not require independent collection. These archival data included indicators of historic utilization (local Medicaid payments, the percentage of births to county residents occurring in the mother's county of residence, percentage of children immunized, and infant mortality) and services already available. Observed utilization data were obtained by surveys in eight rural counties, and the predictor was tested on three additional rural communities. A predictor equation that added to the expected utilization only one variable (the percentage of births to county residents occurring in the mother's county of residence) was found to account for approximately 95% of the variance in observed utilization. This predictor is recommended for planners who need convenient, low-cost market feasibility estimates for proposed project sites and a way to establish intermediate goals or incentives during early project development.

Ambulatory Care↗
PubMed1979

Effect of labetalol on continuous ambulatory blood pressure.

1 The hypotensive action of labetalol was evaluated during 24 h by continuous intra-arterial ambulatory monitoring in 14 patients. The dose used ranged from 300--1800 mg daily. 2 The drug caused a significant reduction of systolic BP in 19 and diastolic BP in 20 of the 24 h of monitoring. Heart rate was also reduced but less markedly than BP. 3 The rapid early morning increase in BP was also effectively controlled. 4 The mild pre-waking increase in BP was not significantly reduced. 5 Labetalol treatment reduced the variation in systolic BP from the lowest observed quarter-hourly mean as compared with pre-treatment values. 6 The quarter hourly mean values were consistently smooth and revealed no sudden variations which might have resulted from postural hypotension.

Adult↗
PubMed1978

The politics of health care regulation: the case of the National Health Planning and Resources Development Act.

This paper examines the political and bureautic dynamics of health regulation under the National Health Planning and Resources Development Act and, to a lesser extent, the Carter Cost Proposal now before Congress. A number of underlying issues that affect the day-to-day exercise of health planning are considered, including the contest between state and local and federal government for program control, jurisdictional conflict between state and local planning agencies, and the unsettled roles to be played by professional planners, consumers, and providers. When we assess regulatory policy in health, these complicating factors must be added to the long list of handicaps that already exist. One important finding is that local planning agencies have embraced the task of health regulation somewhat more fully than had generally been expected. A number of explanations for this are offered. In short, the controlling factors in health planning are political, not technical, and there is more occurring at the state and local levels than many had predicted, although any impact is not likely to be dramatic.

Costs and Cost Analysis↗