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Biomedical subjects

O McClain

Publications and source records attributed to O McClain.

9 recordsLinked to original sources
PubMed1988

The role of iron in the growth and hemolysin (Streptolysin S) production in Streptococcus pyogenes.

Four strains of Streptococcus pyogenes were propagated at 37 degrees C in a reduced iron medium supplemented with Fe3+-citrate to give concentrations of 1 through 11 micrograms per milliliter, in order to observe the effects of iron on growth and on the vitro production of Streptolysin S. Both growth and hemolysin production were observed to be influenced by medium iron concentration of which 1.2 micrograms per ml of iron was critical. Hemolysin was produced during the exponential phase of the growth cycle with maximum yield as the organism entered the stationary phase. Hemolytic activity (which was accepted as the ability of the hemolysin to lyse sheep erythrocytes) fell below detectable levels as the organisms entered fully into the stationary phase (9-10 hours post incubation). Serum (bovine, human, chicken) was observed to have a high stabilizing effect on the hemolysin.

Bacterial Proteins↗
PubMed1985

Immunological response of chickens to eastern equine encephalomyelitis virus.

The dominant immunoglobulin against eastern equine encephalomyelitis (EEE) virus and its duration and the longevity of the EEE virus haemagglutination inhibition (HI) antibodies were determined in sentinel and 125 immunised and hyperimmunised domestic chickens by enzyme-linked immunosorbent assay and the HI test respectively. The chickens ranged in age from 10 weeks to 18 months, were of varied pedigrees and from different countries. Results show that the HI antibody (IgG) is short-lived. It peaks and disappears within 30 days. The secondary response is dominated by the IgM immunoglobulin which is relatively long-lasting. These results are contrary to classical expectations and were observed in all the chickens studied. If these observations are found to be characteristic of birds generally, the present standard method of EEE virus seroepidemiological surveillance must be modified to be effective.

Alphavirus↗
PubMed1979

The role of embolic fat in post-traumatic pulmonary insufficiency. An evaluation of the pulmonary haemodynamics and blood gas levels.

Pulmonary haemodynamic and arterial blood gas changes were measured in dogs subjected to either an intravenous injection of triolein or external trauma, which produced fractures of the ipsilateral femur, tibia and fibula. Musculoskeletal trauma resulted in pulmonary vasoconstriction followed by vasodilatation, arterial hypoxia with a pulmonary shunt of 30% and a 20% decrease in systemic oxygen delivery. Lipid injection produced an increased pulmonary vascular resistance, but no significant hypoxia, pulmonary shunting or inadequate tissue oxygenation. We therefore suggest that pulmonary fat embolism does not account for the pulmonary insufficiency following musculoskeletal trauma.

Animals↗
PubMedDate not supplied

Control of postlaminectomy scar formation: an experimental and clinical study.

Scar formation after laminectomy was evaluated in dogs treated with hemostatic agents, antiinflammatory drugs, or mechanical barriers. Microfibrillar collagen was found to be superior to gelatin foam. The antiinflammatory drugs delayed healing and frequently resulted in abscess formation, and eventually scar filled the defect. The fat grafts formed a viable mechanical barrier. Gelatin foam sponge was compared with microfibrillar collagen for hemostasis with free fat grafts in a clinical series of 50 patients. The latter technique was clearly superior.

Adipose Tissue↗
PubMedDate not supplied

Methylprednisolone in posttraumatic pulmonary insufficiency.

The effect of methylprednisolone, 30 mg/kg on the musculoskeletal trauma model in dogs were compared with the previously reported untreated models. The atelectasis, inflammation, and alveolar membrane thickening were ameliorated. There was a decrease in the coagulopathy of trauma as well as increased cardiac output, pulmonary vasodilitation and a decrease in the pulmonary shunt. Although these changes are salutory, the majority of patients with posttraumatic pulmonary insufficiency can be adequately treated by prompt adequate volume replacement, blood replacement, and appropriate use of cardiotonic drugs. Only in the resistant patient are steroids necessary.

Animals↗
PubMedDate not supplied

Internal fixation of intertrochanteric hip fractures: a clinical and biomechanical study.

One hundred seventy-three cases of intertrochanteric fractures treated by internal fixation are reviewed: 72 treated with the Jewett nail and 101 with the Richards compression hip screw. Both devices maintained adequate reduction in the majority of cases. Treatment failure: loss of fixation, symptomatic joint penetration, aseptic necrosis, malunion and nonunion occurred in 25% of the Jewett nail cases and 6% of the Richards screw cases. In vitro biomechanical studies demonstrate that the compression screw is subjected to less bending stress by acting as a lateral "tension band" in stable reductions and by allowing sliding, thus shortening the bending movement lever arm in unstable reductions. The compression hip screw is valuable in the treatment of intertrochanteric hip fractures. In stable conditions, it acts as a tension band producing more force transmission through the medial cortex, stressing the implant more in tension and less in bending. In unstable conditions with higher shearing forces, the device will shorten the lever arm, decreasing the bending moment, as well as avoiding penetration of the femoral head.

Biomechanical Phenomena↗