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Biomedical subjects

M D Smith

Publications and source records attributed to M D Smith.

At least 559 records · Page 31Linked to original sources
PubMed1976

Effects of carbon monoxide on fixed-consecutive-number performance in rats.

Four rats were trained under a fixed-consecutive-number (FCN) schedule to make sequences of 20 or more consecutive responses on one lever followed by a single response on a second lever. When performance was stable, they were exposed to 200, 400, and 600 parts-per-million (PPM) carbon monoxide (CO) for either 30 or 60 min before and during a 45-min session. Decreases in response rate at CO levels as low as 200 ppm were due to both decreased local response rate and extended pauses. A lowered percentage of reinforcement, due to decreases in response sequence length, was also found at CO levels as low as 200 ppm. This decreased sequence length may reflect effects of CO on response rate, or a disruption of discriminative aspects of FCN schedule performance.

Animals↗
PubMed1976

Clinical technique and success of the esophageal stent to prevent corrosive strictures.

The Reyes technique for the management of severe, acute corrosive injuries of the esophagus has been modified and successfully applied to two children and one adult whose cases are reported. None developed stricture and two were uncomplicated. Esophagomegaly, motility dysfunction, upper gastrointestinal bleeding, and pneumonitis complicated the hospitalization of one child whose subsequent course has been asymptomatic. Until more experience can be recorded, widespread use is not yet recommended.

Age Factors↗
PubMed1975

Injuries in children sustained in free falls: an analysis of 66 cases.

Sixty-six children who fell distances up to 96 feet were studied to determine the frequency and patterns of injuries sustained. Upper extremity, skull, and femoral fractures were most common; there was only one pelvic fracture and one os calcis fracture. Two of the children died, and 64 children returned to normal activities.

Abdominal Injuries↗
PubMed1975

The inhibition of complement-dependent lymphocyte rosette formation by the sera of children with steroid-sensitive hephrotic syndrome and other renal diseases.

Sera from patients with steroid-sensitive nephrotic syndrome (SSNS) in relapse, Henoch-Schonlein purpura with nephritis (HSP) and acute post-strptococcal glomerulonephritis inhibited EAC rosette formation by normal human lymphocytes; a similar effect was seen in some patients with focal glomerulosclerosis, but not in patients with congenital neophrotic syndrome. There was significantly less inhibition by sera of SSNS and HSP patients in remission. There were fewer EAC rosette-forming cells (EAC-RFC) in the blood of three patients with SSNS in relapse, suggesting that such blockade occurred in vivo. These findings, interpreted as evidence of circulating activated C3 in the sera, provide further indirect evidence of the immunopathogenesis of these diseases. Sera of healthy adults inhibited EAC rosette formation to a small extent which correclated inversely with the numbers of EAC-RFC in their blood. The EAC rosette inhibition test may be sensitive enough to detect normal variations of complement activation in healthy individuals.

Adenoids↗
PubMed1974

The interaction of cationic liposomes containing entrapped horseradish peroxidase with cells in culture.

Cationic liposomes composed of sphingomyelin, cholesterol, and stearylamine were prepared with horseradish peroxidase trapped inside. Stable particles were formed in which 10-12% of the enzymic activity appeared to be located at, or near, the outer surface of the liposome. Adsorption and uptake of liposomes by HeLa cells were followed cytochemically by electron microscopy and quantitated by enzyme assay and by the distribution and fate of particles labeled with [(14)C]cholesterol and [(125)I]horseradish peroxidase. The particles were adsorbed by HeLa cells at least 300 times as efficiently as was free horseradish peroxidase. Many of the particles remained at the cell surface, but numerous membrane-bound cytoplasmic inclusions were observed to contain peroxidase-staining material. In addition, many areas of the cell membrane gave a positive staining reaction. It was concluded that many particles (presumably the larger ones) did not gain access to the interior of the cells, many were phagocytized, and some enzyme was transferred to the cell membrane, perhaps as a result of fusion of the liposomal membrane with the cell membrane.

Adsorption↗