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Biomedical subjects

D Williams

Publications and source records attributed to D Williams.

At least 595 records · Page 33Linked to original sources
PubMed1977

Conversion of fused hips to low friction arthroplasty.

Fifty-four hips converted to low friction arthroplasty between 1965 and 1975 have been reviewed one to eleven years after operation. In many cases malposition had led to degenerative changes in the opposite hip, the lumbar spine or the knee, often with severe loss of function due to pain. It was found that total replacement could give useful relief of pain and improved function, though the range of movement obtained was not as good as in primary replacement. An outstanding feature was the correction of inequality of leg length. In general, the results were much better in cases of ankylosis acquired in adult life than in cases of spontaneous fusion after sepsis in childhood. The most important complication was a single case of sciatic palsy.

Adult↗
PubMed1977

The binding of zinc to human deoxyhemoglobin and its possible relevance to the anti-sickling effect of zinc.

We find only one major zinc binding site in crystals of deoxyhemoglobin A. It is located at an interface between adjacent tetramers where residues histidine 116, histidine 117, and glutamate 26 on the beta 1 chain of one tetramer are in close proximity to lysine 16 and glutamate 116 on the alpha 2 chain of a neighboring tetramer. If this intertetramer contact does not exist in the rigid fibers of polymerized deoxyhemoglobin S, then low levels of zinc may promote its formation at random points along the fiber and thereby inhibit the formation of long fibers.

Anemia, Sickle Cell↗
PubMed1976

Anabolic effect of low doses of a fragment of human parathyroid hormone on the skeleton in postmenopausal osteoporosis.

Parathyroid hormone, injected daily in low dosage, exerted anabolic effects on the human skeleton, just as it does in the rat. Four postmenopausal women with primary osteoporosis were treated for six months with a synthetic fragment of human parathyroid hormone (hP.T.H. 1-34), given as a daily injection of 100 mug. This treatment caused a remarkable acceleration of bone turnover, indicated both by isotopic tracer and histological methods. At this normocalcaemic dose level, the increases in bone formation outweighed increases in resorption. Three of the four patients showed more positive calcium balances, and mean increases in calcium and phosphorus balances were statistically significant for the group as a whole, the changes being principally due to increased intestinal absorption of both elements. Many modifications of the present method of hormone administration are possible which could further increase the preponderance of anabolic effects. These results suggest that low doses of hP.T.H. 1-34, alone or in combination with other agents, may prove useful in the treatment of osteoporosis.

Absorption↗
PubMed1976

The modification of the electron microscope for special crystallographic applications.

The conversion of the transmission electron microscope to a convergent-beam camera and shadow microscope with facilities for experiments using two specimens located in different planes is discussed, with particular reference to older models such as the Elmiskop 1. The conversion requires the removal of the intermediate lens in some microscopes and thus prevents them from operating in their original capacity. The Elmiskop 1 has a wide intermediate lens pole-piece which does not unduly restrict the diffraction angle. The smallest crystal spacing contributing to the convergent-beam diffraction pattern is 0.05 nm.

Crystallography↗
PubMed1976

Airway obstructed by foreign material: the Heimlich maneuver.

To investigate the application of a cough-creating thrust for the removal of airway-obstructing foreign material, the thrust was applied to six adult male anesthetized volunteers at the waist, at the low chest level, and at the midchest level, with the subjects in both the horizontal-lateral and the sitting positions. Air volume, peak air flow rate, and airway measurements were made. Both the low chest and midchest thrusts produced significantly better results than did the abdominal thrust. There were no side effects attributable to the thrusts. The ease of application and consistently better level of results indicate that the chest thrust is the technique of choice. The application of the chest thrust should be integrated into the concepts of basic life-support and cardiopulmonary resuscitation.

Adolescent↗
PubMed1976

Characterizatiion of rat genetic sequences of Kirsten sarcoma virus: distinct class of endogenous rat type C viral sequences.

The nucleic acid sequences found in DNA and RNA from rat cells which are homologous to Kirsten sarcoma virus have been characterized. The homologous sequences are present in multiple copies per diploid rat cellular genome in a variety of different rat cellular dna's. In certain cells that constitutively express only low levels of sequences homologous to Kirsten sarcoma virus, bromodeoxyuridine treatment leads to the expression of high levels of these sequences in RNA. Supernatants from cell lines producing the sequences homologous to Kirsten sarcoma virus contain high levels of these sequences which are purified to the same degree as the previously known rat type C viral nucleic acid sequences by type C particles being released from such cells. The results indicate that the sequences in rat cells homologous to Kisten sarcoma virus have three characteristics of known mammalian type C viruses, and suggest that at least part of Kirsten sarcoma virus rat-derived sequences represent a distinct class of endogenous rat type C virus that has no detectable homology to the other known class of endogenous rat type C virus.

Animals↗
PubMed1976

Type C particle-positive and type C particle-negative rat cell lines: characterization of the coding capacity of endogenous sarcoma virus-specific RNA.

Various rat cell lines have been analyzed for expression of endogenous RNA homologous either to RT21C, a typical rat type C virus, or to Kirsten sarcoma virus. Cells have been found that express either (i) high levels of RNA homologous to RT21C rat type C virus and low levels of RNA homologous to Kirsten sarcoma virus (RT21Chigh,sarclow) or (ii) high levels of RNA homologous to Kirsten sarcoma virus and low levels of RNA homologous to typical rat type C virus (sarchigh, RT21Clow). The properties of these two classes of cell lines have been compared. Each type of cell contains an equal amount of the expressed RNA on polysomes. Cell lines that are RT21Chigh produce abundant rat p30 nad p12 structural proteins and release rat type C particles containing viral RNA and reverse transcriptase into supernatant fluids from these cultures. Cell lines that are sarchigh,RTC21Clow have no detectable rat viral p12 protein and no p30 protein immunoreactive in even broad interspecies radioimmunoassays, and do not release type C particles into the supernatant from the cultures. When the particle-negative cell lines are superinfected with heterologous mouse or wooly type C viruses or are producing typical rat type C virus particles, the endogenous sarcoma virus-specific RNA is secreted from these cells. The sarcoma virus-specific RNA can be transcribed in complementary DNA in the endogenous reverse transcriptase reactions carried out in vitro with such virus preparations. However, exposure of cells that are permissive to the helper virus with the particles containing sarcoma virus-specific RNA has not yet resulted in cell transformation or in the synthesis of these RNA sequences. The results suggest: (i) that the first step in the genesis of sarcoma viruses involves the packaging of this expressed sarcoma virus-specific RNA in helper viral particles; (ii) that efficient transmission of the sarcoma virus-specific RNA requires additional events; and (iii) that the formation of a stable sarcoma virus by recombination between the helper viral genome and part of the rescued sarcoma virus-specific RNA is much less common event than the rescue process itself.

Base Sequence↗
PubMed1976

The chemoattraction of neutrophils by heterologous and homologous cytotoxic sera.

Neutrophils (PMN) migrated in vitro chemotactically along concentration gradients of heterologous and homologous leukocytotoxic, complement-active sera. The heterologous systems consisted of normal, non-immune nurse shark or dog serum and human PMN; the homologous systems consisted of human or dog immune sera and human or dog PMN, respectively. Chemotaxis was induced 1) by fresh cytotoxic sera, 2) by complement alone if the cytotoxic antibodies were with the responding cells or if the cells were passively sensitized with the antibodies, and 3) by individual and combined complement components if the corresponding intermediate PMN-antibody-complement component complexes were the migrating cells. These observations represent a new mechanism of immune chemotaxis: the chemotactic stimulation is a direct consequence of a gradient-controlled immune reaction occuring at and involving the surface of the chemoattracted cell. This mechanism is distinctly different from that which depends on chemotactic factors produced or released independent of and at a distance from the responding cells.

Animals↗