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Biomedical subjects

A Asch

Publications and source records attributed to A Asch.

15 recordsLinked to original sources
PubMed1999

Prenatal diagnosis and selective abortion: a challenge to practice and policy.

Professionals should reexamine negative assumptions about the quality of life with prenatally detectable impairments and should reform clinical practice and public policy to improve informed decision making and genuine reproductive choice. Current data on children and families affected by disabilities indicate that disability does not preclude a satisfying life. Many problems attributed to the existence of a disability actually stem from inadequate social arrangements that public health professionals should work to change. This article assumes a pro-choice perspective but suggests that unreflective uses of prenatal testing could diminish, rather than expand, women's choices. This critique challenges the view of disability that lies behind the social endorsement of such testing and the conviction that women will or should end their pregnancies if they discover that the fetus has a disabling trait.

Abortion, Eugenic↗
PubMed1995

Human immunodeficiency virus 1 reservoir in CD4+ T cells is restricted to certain V beta subsets.

The human immunodeficiency virus 1 (HIV-1) replicates more efficiently in T-cell lines expressing T-cell receptors derived from certain V beta genes, V beta 12 in particular, suggesting the effects of a superantigen. The targeted V beta 12 subset was not deleted in HIV-1-infected patients. It was therefore possible that it might represent an in vivo viral reservoir. Viral load was assessed by quantitative PCR with gag primers and with an infectivity assay to measure competent virus. It was shown that the tiny V beta 12 subset (1-2% of T cells) often has a higher viral load than other V beta subsets in infected patients. Selective HIV-1 replication in V beta 12 cells was also observed 6-8 days after in vitro infection of peripheral blood lymphocytes from normal, HIV-1 negative donors. Viral replication in targeted V beta subsets may serve to promote a biologically relevant viral reservoir.

Adult↗
PubMed1993

T-cell antigen receptor V beta subsets are not preferentially deleted in AIDS.

OBJECTIVE: Evidence for an HIV-1-associated superantigen (SAg) has been presented. Here we test whether targeted T cells are preferentially depleted in AIDS. DESIGN: The T cell antigen receptor (TCR) V beta repertoire was compared in 44 HIV+ hemophiliac patients and in 27 controls. METHODS: Eleven TCR V gene-specific monoclonal antibodies (MAb), representing approximately one-third of the V beta repertoire were used to measure T-cell numbers expressing V beta and V alpha genes in both the CD4 and the CD8 subsets by two-color immunofluorescence. RESULTS: The percentage of T cells expressing these V genes could be accurately quantitated in both the CD4 and the CD8 T-cell populations and at various clinical stages of disease progression. No preferential deletion of any particular V gene subsets was detected. CONCLUSION: CD4 T-cell depletion in AIDS is not V beta-selective.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Cytokine-induced respiratory burst of human neutrophils: dependence on extracellular matrix proteins and CD11/CD18 integrins.

Human polymorphonuclear leukocytes (PMN) released large quantities of hydrogen peroxide in response to tumor necrosis factor, but only when the cells were adherent to surfaces coated with extracellular matrix proteins. The PMN did not respond when exposed to cytokines and matrix proteins in suspension, or when exposed to cytokines while adherent to surfaces coated with stearic acid. PMN from children with genetic deficiency of the CD11/CD18 integrins underwent a normal respiratory burst upon adherence to uncoated polystyrene, but not in response to tumor necrosis factor when tested on polystyrene that was coated with serum, fibronectin, vitronectin, fibrinogen, thrombospondin, or laminin. Anti-CD18 antibodies, alone of sixteen antibodies tested, induced a similar defect in PMN from normal donors, when the PMN were tested on surfaces coated with serum, fibrinogen, thrombospondin, or laminin; no defect was induced by the anti-CD18 monoclonal antibody IB4 in normal PMN tested on surfaces coated with fibronectin or vitronectin. Thus, for cytokines to induce a respiratory burst in PMN, the cells must be able to use CD11/CD18 integrins and must interact with matrix proteins in the solid phase. CD11/CD18, which is already known to serve as a receptor for fibrinogen, may also be a receptor for thrombospondin and laminin. Finally, receptor(s) exist on PMN for fibronectin and vitronectin which are not blocked by the anti-CD18 antibody IB4 but which are nonetheless CD11/CD18 dependent.

Antibodies↗
PubMed1985

Therapists with disabilities: theoretical and clinical issues.

Disability as a characteristic of the therapist needs to be addressed for several reasons. First, substantial evidence indicates that people without visible disabilities or physical differences regard persons who diverge from ideals of physical perfection and norms of physical acceptability with a variety of emotions which--at the very least--alter ordinary social interaction. Second, the psychoanalytic literature on therapy with disabled patients and the developmental literature about people with disabilities reinforce the generally negative or ambivalent attitudes about the mental well-being and potential for productivity and intimacy of people with disabilities. As a consequence of both general acculturation and professional training in psychology and psychoanalysis, professionals in charge of admissions have frequently denied competent disabled people the graduate education which is prerequisite to psychoanalytic training and professional employment. Mental health practitioners who make up the training committees of analytic institutes have frequently been reluctant to accept a disabled candidate for psychotherapy or psychoanalytic training. Once trained, many disabled clinicians have faced hurdles in obtaining employment, in advancing within their profession, in being selected as faculty members or supervisors, and even in obtaining referrals from nondisabled colleagues. After briefly describing the literature on attitudes of the nondisabled toward people with physical impairments, we will present the reasons for the reluctance to train disabled people as therapists. We will include material on how disabled people work with their disabilities in the analytic process and will bring in analogies to practitioners who are members of racial or cultural minority groups.

Attitude↗
PubMed1980

Observations on the "cytoskeleton" of human platelets.

Structural study of rapidly lysed platelets supports the view that that shape change involves a change in state of the microfilaments which contain actin. The microtubule "bundle" appears to be a continuous coil. Proteolysis of a high molecular weight band is observed in platelets which can no longer form filopodia after suppression by local anesthetics.

Blood Platelets↗
PubMed1976

A calcium-sensitive preparation from Physarum polycephalum.

Differential ultracentrifugation of an extract of the plasmodium of Physarum polycephalum yields a high-speed fraction which exhibits calcium-sensitive adenosine triphosphate activity at low ionic strength. The rate of inorganic phosphate production increased from 2- to 25-fold in different preparations when the calcium concentration was increased from about 10(-8) to 10(-5) M. Complement fixation using specific antibody to Physarum myosin showed the fraction to contain 3% myosin. By electron microscopy, actin-like microfilaments 50--150 nm long were present. Addition of pure rabbit F-actin or myosin to this fraction activated the ATPase measured in EGTA and so partially reversed the calcium sensitivity. If muscle myosin was added to the supernatant from which the fraction was centrifuged, a "hybrid complex" was obtained which included actin and additional protein from the plasmodium, and this hybrid was also calcium sensitive. Over 85% of the calcium-sensitive, magnesium-activated ATPase could be precipitated by sequential "hybrid" formation. The calcium sensitivity of the hybrid was maximal when formed at the lowest ratios of added myosin to Physarum proteins. It is concluded that the results do not allow a simple interpretation along the lines of either actin-linked or myosin-linked sensitivity. Evidence consistent with both a form of actin-linked and myosin-linked sensitivity is present in our results.

Actins↗