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Biomedical subjects

S Haber

Publications and source records attributed to S Haber.

8 recordsLinked to original sources
PubMed1989

Use of nonphysician providers in the Medicare program: assessment of The Direct Reimbursement of Clinical Social Workers Demonstration Project.

Rising Medicare costs and concern about inadequate access to physician services have prompted interest in extending independent practitioner status to nonphysician providers. This paper reviews the findings from a demonstration project that tested whether recognizing clinical social workers (CSWs) as independent practitioners in the Medicare program would be a cost-effective method to improve access to needed mental health services. The demonstration showed little impact on access and no clear evidence of savings, despite the lower cost of CSW services compared with those of psychiatrists. Differences between CSWs and psychiatrists in treatment patterns and treatment settings, however, suggested that for some patients CSWs might be an appropriate alternative source of care.

Aged↗
PubMed1988

Tracing intrinsic fiber connections in postmortem human brain with WGA-HRP.

Modern methods for tracing central nervous system pathways depend largely on active axonal transport mechanisms and are carried out in in vivo animal experiments. This report describes the ability to trace axons and label cell bodies in postmortem human material, using injections of wheat germ agglutinin horseradish peroxidase. Furthermore, it demonstrates the compatibility of this method with immunocytochemical techniques for localizing neurotransmitters. Thus it is possible to study the intrinsic circuitry or short connections in brain regions such as cortex in both normal and pathological material, and, using double label methods, determine the transmitter systems involved. It also raises the issue of the mechanisms which are involved in the movement of the tracer molecule.

Axonal Transport↗
PubMed1986

Fetal neuronal grafts in monkeys given methylphenyltetrahydropyridine.

Fetal substantia nigra cells of two different gestational ages were successfully transplanted into the brains of three methylphenyltetrahydropyridine-treated monkeys with severe parkinsonian motor and behavioural deficits. Functional improvement continued for 10 weeks after cell grafts into the striata of two monkeys with substantial numbers of tyrosine-hydroxylase-positive fetal neurons at necropsy. Behavioural improvement was correlated with increases in cerebrospinal fluid (CSF) homovanillic acid (HVA) concentrations after the transplants. A control monkey with inappropriately placed transplanted cells of an earlier gestational age remained severely parkinsonian and died during a similar period. CSF HVA fell slightly in this monkey from the low level seen before the transplants. Fetal dopamine neurons of two different gestational ages appear to survive transplantation in primates and have biochemical and functional effects.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1985

Antigen presentation by hapten-specific B lymphocytes. II. Specificity and properties of antigen-presenting B lymphocytes, and function of immunoglobulin receptors.

The studies described in this paper were designed to examine the ability of hapten-binding murine B lymphocytes to present hapten-protein conjugates to protein antigen-specific, Ia-restricted T cell hybridomas. BALB/c B cells specific for TNP or FITC presented hapten-modified proteins (TNP-G1 phi, TNP-OVA, or FITC-OVA) to the relevant T cell hybridomas at concentrations below 0.1 microgram/ml. Effective presentation of the same antigens by B lymphocyte-depleted splenocytes, and of unmodified proteins by either hapten-binding B cells or Ig spleen cells, required about 10(3)-to 10(4)-fold higher concentrations of antigen. The use of two different haptens and two carrier proteins showed that this extremely efficient presentation of antigen was highly specific, with hapten specificity being a property of the B cells and carrier specificity of the responding T cells. The presentation of hapten-proteins by hapten-binding B lymphocytes was radiosensitive and was not affected by the depletion of plastic-adherent cells, suggesting that conventional APCs (macrophages or dendritic cells) are not required in this phenomenon. Antigen-pulsing and antibody-blocking experiments showed that this hapten-specific antigen presentation required initial binding of antigen to surface Ig receptors. Moreover, linked recognition of hapten and carrier determinants was required, but these recognition events could be temporally separated. Finally, an antigen-processing step was found to be necessary, and this step was disrupted by ionizing radiation. These data suggest a role for B cell surface Ig in providing a specific high-affinity receptor to allow efficient uptake or focusing of antigen for its subsequent processing and presentation to T lymphocytes.

Animals↗