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Biomedical subjects

W K Smith

Publications and source records attributed to W K Smith.

At least 55 records · Page 3Linked to original sources
PubMed1985

Influence of shoot structure on light interception and photosynthesis in conifers.

The influence of shoot structure on net photosynthesis was evaluated under field conditions for the central Rocky Mountain (United States) conifers Picea engelmannii (Parry ex Engelm.), Abies lasiocarpa ([Hook] Nutt.), and Pinus contorta (Engelm.). In all species, the greater number of needles per unit stem length on sun shoots correlated with a smaller silhouette leaf area to total leaf area ratio (STAR). Decreased STAR was due primarily to greater needle inclination toward the vertical, plus some needle mutual shading. However, photosynthesis expressed on a total leaf area basis did not decrease in sun shoots (lower STAR) but remained nearly constant at approximately 3 micromoles per square meter per second over a wide range of STAR (0.1 to 0.3). Relatively low light saturation levels of 200 to 1400 microeinsteins per square meter per second and diffuse light to 350 microeinsteins per meter per second maintained photosynthetic flux densities in inclined and/or shaded needles at levels comparable to those in unshaded needles oriented perpendicular to the solar beam. As a result, net CO(2) uptake per unit stem length increased as much as 2-fold in sun shoots (low STAR) in direct proportion to increasing needle density.

Journal Article↗
PubMed1984

Interferon enhances antibody-dependent cellular cytotoxicity when suboptimal concentrations of antibody are used.

Polymorphonuclear leukocytes (PMN) and killer (K) cells isolated from buffy coats from normal volunteers were tested for antibody-dependent cellular cytotoxicity (ADCC) against chicken erythrocytes (CRBC) with and without the addition of interferon (IFN). Maximum enhancing activity was found when the anti-CRBC antibodies in the ADCC reaction were at suboptimal concentrations. All three species of pure recombinant Escherichia coli-derived interferon were compared for their ability to enhance ADCC in both effector systems. Recombinant IFN-gamma was found to be effective at lower doses than recombinant IFN-alpha A or recombinant IFN-beta, although maximum activity for all three species was similar in the PMN system. IFN-gamma also enhanced K-cell ADCC but to a lesser extent than in the PMN system. There appeared to be individual variation in response of the K-cell ADCC system to IFN-alpha A and IFN-beta at the doses tested.

Animals↗
PubMed1984

The synthesis and accumulation of cholesteryl esters by the developing embryo of the domestic fowl.

A comparative study has been made of the accumulation and synthesis of cholesteryl esters in the liver, yolk sac membrane, and yolk contents of the chick embryo during the last week of development. This involved a comparison of the cholesteryl esters synthesized during incubation in vitro with 14C-cholesterol with those accumulated during incubation in vivo. Results indicated that the considerable accumulation of cholesteryl esters, mainly cholesteryl oleate, that occurred within the liver during embryo development arose from synthesis in the yolk sac membrane. This suggested a specific role in the transport of yolk lipid into the embryo. With the approach of hatching the ability of the liver to synthesize its own cholesteryl esters increased while that of the yolk sac membrane decreased.

Animals↗
PubMed1982

Split peroneus brevis transfer: nonosseous ankle stabilization procedure.

There have been numerous articles written on surgical reconstruction of the lateral collateral ligaments. This paper discusses a different type of lateral ankles stabilization procedure performed on 19 patients at Doctors General Hospital, with mean follow-up of 14 months. The procedure is done entirely with soft tissue; no osseous structures are involved. The authors have utilized tendon, particularly part of the peroneous brevis tendon, to reinforce the lateral capsule and collateral ligaments. It is this technique and some modifications that are presented.

Adolescent↗
PubMed1980

Importance of Aerodynamic Resistance to Water Use Efficiency in Three Conifers under Field Conditions.

The quantitative importance of aerodynamic resistance to H(2)O vapor and CO(2) exchange was determined for shoots from saplings of three conifers (Abies lasiocarpa [Hook] Nutt., Pinus contorta Dougl., Juniperus communis L.) under natural conditions in the field. A combination of relatively low stomatal resistances (<300 seconds per centimeter) and low wind speeds (<30 centimeters per second) led to substantial contributions of the aerodynamic resistance (R(wv) (a)) to water use efficiency (WUE = photosynthesis/transpiration) for all three species. For A. lasiocarpa, transpiration was calculated to be 44% less and photosynthesis 17% less due to the presence of R(wv) (a), which led to a predicted increase in WUE of 57% compared to the calculated WUE when R(wv) (a) was assumed negligible. Similar increases in WUE were computed for P. contorta (48%) with somewhat smaller values for J. communis (34%). These results are discussed in terms of the estimated importance of R(wv) (a) on water and photosynthetic relations of plants that have relatively low stomatal resistances and grow in microhabitats with low winds.

Journal Article↗
PubMed1979

Microcapillary agglutination assay for detection of specific antileukocyte reactivity in neutropenic patients.

Serum leukoagglutinating activity against the leukocytes of four patients with neutropenia was demonstrated using a modified microcapillary agglutination test. Cells from a panel of donors proved useful in attempting to define the identity of the antigens involved. In one instance anti-HLA-A9 activity could be demonstrated in a patient possessing HLA-A9. In the other three individuals no definite antigen assessment to HLA Series A and B antigens or the Lalezari series of neutrophil antigens could be made. Two of the patients' sera showed cross-reactivity and may be reactive with the same antigen or antigenic group. The microcapillary agglutination test appears to be useful in the evaluation of possible cases of autoimmune neutropenia.

Adult↗
PubMed1979

The effect of rapeseed meal on the energy metabolism of laying hens.

1. The effect of 100 g rapeseed meal (RSM)/kg diet on the energy metabolism of hybrid laying hens was examined by indirect calorimetry. Thyroid hormone concentrations, thyroid weight, liver weight and body weight, egg production and food intake were also measured. 2. Fasting heat production was significantly lower in hens receiving RSM than in controls, but this difference disappeared when the birds were fed. 3. Thyroid hormone concentrations decreased, while thyroid and liver weights increased slightly; none of these effects was significant. Body weight, egg production and food intake were unaffected and no liver haemorrhages were noted. 4. The maintenance metabolisable energy (ME) requirement of control and treated birds, estimated from short-term energy balance measurements, was 474 kJ/kg0.75 d; net availability of ME in both treatments was 0.85.

Animal Feed↗
PubMed1976

Hemorrhagic diathesis in a carrier of hemophilia B.

A carrier of hemophilia B was found to have an unusually low factor IX level of 13 per cent. Her history of previous bleeding and the hospital course following elective dental extractions were consistent with a mild hemorrhagic diathesis. The patient is a member of a rare kindred of hemophiliacs. The mean level of factor IX in 12 carriers in this kindred was 42 per cent, with a range of 13 to 100 per cent. This patient represents the sixth reported case in which a female carrier of factor IX deficiency was symptomatic.

Adult↗
PubMed1975

Relation between Mesophyll Surface Area, Photosynthetic Rate, and Illumination Level during Development for Leaves of Plectranthus parviflorus Henckel.

The influence of illumination level during leaf development on the mesophyll cell surface area per unit leaf area (A(mes)/A), CO(2) resistances, and the photosynthetic rate was determined for leaves of Plectranthus parviflorus Henckel. The relative importance of A(mes)/A versus CO(2) resistances in accounting for observed changes in photosynthesis was quantitatively evaluated using equations based on analogies to electrical circuits.When the illumination during development was raised from 900 to 42,000 lux, the leaves more than tripled in thickness as the mesophyll cells increased in size and frequency, which caused A(mes)/A to go from 11 to 50. The net rate of photosynthesis at light saturation concomitantly increased 4-fold, reflecting a corresponding decrease in the total resistance for CO(2) movement per unit leaf area. However, the CO(2) resistance per unit area of mesophyll cells remained about 580 seconds per centimeter for leaves grown under 900 to 42,000 lux. Thus, for P. parviflorus, the increased photosynthetic rate for leaves developing under higher illuminations resulted from a higher A(mes)/A, not from changes in the CO(2) resistances within individual mesophyll cells, expressed per unit area of cell surface. Results are discussed in terms of previously observed increases in thickness, internal leaf area, and photosynthetic rates for sun versus shade leaves on various plant species.

Journal Article↗