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Biomedical subjects

S Weinstein

Publications and source records attributed to S Weinstein.

155 records · Page 9Linked to original sources
PubMedDate not supplied

The interplay between X-ray crystallography, neutron diffraction, image reconstruction, organo-metallic chemistry and biochemistry in structural studies of ribosomes.

Crystals of ribosomes, their complexes with components of protein biosynthesis, their natural, mutated and modified subunits, have been subjected to X-ray and neutron crystallographic analyses. Electron microscopy and 3-dimensional image reconstruction, supported by biochemistry, genetic, functional and organo-metallic studies were employed for facilitating phasing of the crystallographic data. For example, a monofunctional multi heavy-atom cluster (undecagold) was designed for covalent and quantitative binding to ribosomes. The modified particles were crystallized isomorphously with the native ones. Their difference-Patterson maps contain indications for the usefulness of these derivatives for subsequent phasing. Models of the ribosome and its large subunit were reconstructed from tilt series of 2-dimensional sheets. The comparison of the various reconstructed images enabled an initial assessment of the reliability of these models and led to tentative assignments of several functional features. These include the presumed sites for binding mRNA and for codon-anticodon interactions, the path taken by the nascent protein chain and the mode for tRNA binding to ribosomes. These assignments assisted in the design of biologically meaningful crystal systems. The reconstructed models are being used to identify structural features in initial density maps derived from X-ray and neutron diffraction data.

Crystallography↗
PubMedDate not supplied

Crystallography of ribosomes: attempts at decorating the ribosomal surface.

Crystals of various ribosomal particles, diffracting best to 2.9 A resolution were grown. Crystallographic data were collected from shock frozen crystals with intense synchrotron radiation at cryo temperature. For obtaining phase information, monofunctional reagents were prepared from an undecagold and a tetrairidium cluster, by attaching to them chemically reactive handles, specific for sulfhydryl moieties. Heavy-atom derivatives were prepared by a specific and quantitative binding of the undecagold cluster to an exposed sulfhydryl prior to the crystallization. To create potential binding sites on the halophilic and thermophilic ribosomal particles, which yield our best and most interesting crystals, exposed reactive moieties were inserted, using genetic and chemical procedures. In order to choose the appropriate locations for these insertions, the surfaces of the ribosomal particles were mapped by direct chemical determination of exposed amino and sulfhydryl groups.

Bacteria↗
PubMedDate not supplied

Testing sensibility, including touch-pressure, two-point discrimination, point localization, and vibration.

Sensibility is much more than protective sensation, and the examiner needs to consider the various degrees of residual sensibility that influence both diagnosis and prognosis. Towards that end, objective tests of the extent and nature of peripheral nerve involvement should be employed. Objective tests reflect the current condition of sensibility and are not affected by cognitive influences, such as re-education. Most current clinical instruments used for measurement of sensibility fail to meet the criteria of an objective test because they: (1) can be shown to lack necessary sensitivity, and (2) are too variable. As a consequence, regardless of whether these instruments have been used in controlled clinical studies or are in common use, their results will not replicate with repeated testing. Unfortunately, therefore, sensibility changes will potentially go unrecognized in a large number of patients and many will be detected only in the later stages of peripheral nerve abnormality, when possibilities of treatment are less effective. This article discusses sensibility testing from the standpoint of what is known regarding strengths and weaknesses of various tests and sensory modalities, and makes an appeal for clinicians to review the instruments they use critically for sensibility measurement with regard to stimulus control. Clinicians must insist on validity and reliability in their instruments before they have confidence in the data obtained.

Discrimination, Psychological↗
PubMedDate not supplied

Predicting adult stature: a comparison of methodologies.

Three methods of predicting a child's adult height are in common use: Bayley and Pinneau (1952), Tanner et al. (1975) and Roche et al. (1975). The relative accuracies of these methods have been assessed using growth records (22 male, 24 female) from the Child Research Council, Denver, Colorado. A series of six ages from five years to mid-adolescence was examined. Testing all methods and ages within each sex with a multivariate design yielded significant differences in the methods' accuracies, but inspection of the data by age disclosed that the major discrimination occurred during adolescence, not childhood. Results also indicated that the method of skeletal age assessment (either Greulich--Pyle or TW2) is more critical to accurate height prediction than is the choice of prediction method per se. This is because of inter-population differences in the rate and pattern of progress towards maturity and thus indicates the need to compare the children under examination to the most appropriate population standards available.

Adolescent↗
PubMedDate not supplied

Total quality management at Bethesda, Inc.

This article describes 4 years of TQM implementation at Bethesda, Inc., a private not-for-profit diversified healthcare organization. Bethesda has used a comprehensive implementation strategy involving the use of process improvement teams, hoshin planning, daily management of critical processes, and quality function deployment. The article includes four process improvement case studies demonstrating the use of the seven quality control tools and a nine-step process improvement model. Factors contributing to processes as well as obstacles are described.

Ambulatory Surgical Procedures↗
PubMedDate not supplied

AIDS: the disease, the demographics, the devastation.

The etiology and pathophysiology of AIDS are reviewed: HIV-1 infection and changes in T4 lymphocytes; secondary infections, such as Pneumocystis carinii pneumonia and tuberculosis; and tumors, such as Kaposi's sarcoma. The CDC has classified HIV infection into four groups based on clinical manifestations and immune system changes. Male homosexuals and bisexuals are most at risk for HIV infection. The incidence of infection among infants and heterosexuals will increase. Public health education programs should focus on safe (monogamy, condom use) and unsafe (unprotected intercourse, anal-receptive sex) sexual practices, as well as on risky behavior, such as needle sharing. Home care management of AIDS patients is safe and cost-effective.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Computerized food service as a patient support system.

This paper compares an operations support system with an information system in the area of clinical food service. The advantages of a computerized dietary system over a manual system are discussed. A flexible, data-independent information system facilitates inventory and production control and extends the benefits of nutritional analysis to more patients. Health professionals are freed from routine clerical duties, and labor costs are minimized through use of the system.

Computers↗
PubMedDate not supplied

Fifty years of somatosensory research: from the Semmes-Weinstein monofilaments to the Weinstein Enhanced Sensory Test.

In this paper, the author's long history with somatosensation is overviewed with special emphasis on the creation of objective tests of sensibility. Objective testing is discussed using numerous examples from the author's experiences. The creation of the Semmes-Weinstein monofilaments is discussed. Tests employing the Semmes-Weinstein monofilaments, two-point discrimination, and point localization are discussed with reference to the fact that these tests reflect specific differences between the central and peripheral nervous systems. Towards that end, contrasts are made between the Semmes-Weinstein esthesiometer and both the two-point discrimination and the point-localization tests. A new enhancement of the original Semmes-Weinstein monofilament test, the Weinstein Enhanced Sensory Test (WEST), is introduced. Advantages of the WEST are discussed.

Evoked Potentials, Somatosensory↗