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Biomedical subjects

T Stewart

Publications and source records attributed to T Stewart.

106 records · Page 6Linked to original sources
PubMed1975

Quantitation of T- and B-lymphocytes in peripheral blood of patients with solid tumours. I. Relation to other parameters of in vivo and in vitro immune competence.

The absolute number of T- and B-lymphocytes in the peripheral blood was measured in 22 patients with disseminated nonlymphoid solid malignant tumours. Patients with normal absolute lymphocyte counts had normal absolute numbers of T- and B-lymphocytes; patients with low counts had low numbers. The percentage of T- and B-lymphocytes was similar, in both groups of patients, to that of healthy control subjects. Patients with a normal absolute lymphocyte count had better in vitro lymphocyte responses to mitogenic agents than did patients with low absolute lymphocyte counts. Improvement of depressed in vitro lymphocyte responses to normal on culture of cells in AB plasma was most likely in patients with normal absolute lymphocyte counts. The absolute lymphocyte count by itself, then, provides useful information about the immune status of patients with solid malignant tumours.

Adult↗
PubMed1974

Mixed leucocyte culture blocking factor activity in the plasma of patients with cancer.

Plasma samples obtained from 74 patients with malignant disease were assayed for their ability to suppress or block the mixed lymphocyte reactivity of random normal donors. 24 of the 74 patients investigated had evidence of mixed lymphocyte culture blocking factoractivity (MLC-BFA). 19 of 33 patients with disseminated disease had evidence of MLD-BFA whereas in only 5 of 41 patients with localized disease was evidence of BFA found. There was a relationship between a history of previous blood transfusion inthe 6-month period prior to study and the presence of MLC-BFA in patients' plasma. Excluding this group of patients, where previous transfusion might have been responsible for MLC-BFA and excluding, too, that group of patients with a history of past pregnancy,there remained still 11 patients with evidence of BFA in their plasma. Nine of these11 had widely disseminated and progressiv disease. MLC-BFA was found in both IgM and IgG fractions of plasma. Plasma with MLC-BFA was found to suppress normalin vitro lymphocyte responses to mitogens PWM and PHA. The MLC-BFA assay utilized in this work may provide the means of monitoring cancer patients in order to detect 'blocking' antibody.

Antigen-Antibody Complex↗
PubMedDate not supplied

Long-term wear of HIPed alumina on alumina bearings for THR under microseparation conditions.

The long term wear and wear debris generated in HIPed alumina on alumina bearings for hip prostheses with microseparation in vitro is compared to standard simulator conditions and ex vivo specimens. Microseparation studies were completed to five million cycles at two severity levels in attempts to rigorously evaluate the long-term tribological performance of the bearings. During the first million cycles (bedding-in) of the microseparation tests characteristic stripe wear was observed on all of the femoral heads with a matching area on the rim of the acetabular inserts. Under mild microseparation conditions an average wear rate of 0.55 mm3/million cycles was observed during the initial million cycles which reduced to a steady state level of 0.1 mm3/million cycles. Under more severe conditions an average wear rate of 4.0 mm3/million cycles was observed during bedding-in which reduced to a steady state level of 1.3 mm3/million cycles. These compare to a bedding-in wear rate of 0.11 mm3/million cycles and steady-state wear rate of 0.05 mm3/million cycles for the same material under normal simulation with no microseparation. Furthermore, under microseparation the wear mechanisms and wear debris were similar to those observed in previous alumina retrieval studies with debris ranging from 10 nm to 1 microm in size.

Journal Article↗
PubMedDate not supplied

Functional role for c-myc in mitogenic response to platelet-derived growth factor.

In BALB/c-3T3 cells, expression of the c-myc gene is stimulated by platelet-derived growth factor (PDGF). Using mouse mammary tumour virus promoter: c-myc recombinant plasmids, 3T3 sublines were constructed in which hydrocortisone was the primary determinant of myc mRNA content. The c-myc gene product is an intracellular mediator of the growth response to PDGF though probably not the only one. Both the human and the mouse c-myc genes stimulate clonal growth of 3T3 cells in PDGF-free medium suggesting new strategies for analysis of oncogenes which do not function in focus formation assays.

Animals↗
PubMedDate not supplied

U.S. Army air ambulance operations in El Paso, Texas: a descriptive study and system review.

OBJECTIVES: To analyze a high-volume military air ambulance unit and review the U.S. Army air medical transport system and Military Assistance to Safety and Traffic (MAST) program. METHODS: The setting was a remote medical system with numerous ground emergency medical services. All patients transported between January 1, 1996, and February 28, 1998, were included. Patients who were dead on scene or for whom records were unavailable were excluded. A retrospective review of transport and available inpatient records was conducted. RESULTS: Five hundred seventeen patients were transported during the study period; 461 patients met inclusion criteria (89%). Of these, 70% were classified as trauma; 30% possessed medical or other surgical diagnoses. Prehospital responses numbered 71.6%, while 28.4% were interhospital transfers. Missions averaged 23.4 minutes per flight, with no major aircraft mishaps. Prehospital utilization review showed appropriate use; 35% of interhospital trauma and 11% of interhospital nontrauma missions were staffed inadequately by these criteria. Time intervals, procedures, and program impact are discussed. CONCLUSION: This and similar units participating in the MAST program provide effective air transport in settings underserved by civilian programs. Quality and wartime readiness could be improved by centralized medical direction, treatment and transfer protocols, and enhanced training of medics. Further investigations of the clinical impact of advanced training and a two-medic aircrew model are warranted.

Adolescent↗
PubMedDate not supplied

Solomon Islands dengue seroprevalence study--previous circulation of dengue confirmed.

Since there were no confirmed outbreaks of dengue on record an extensive search of available records and a seroprevalence study were undertaken to determine if there was evidence of past dengue virus infections in the Solomon Islands. Hospital and Health Department records revealed a suspected dengue outbreak in 1982 and deaths attributed to dengue in 1995 and 1996. Serum samples from blood donors were analyzed for the presence of IgG antibodies specific for flavivirus and dengue virus. A total of 39% of the 515 samples, predominantly from adult males from Honiara, demonstrated IgG antibodies specific for dengue; 28% (26 of 93) were monotypically positive by plaque reduction neutralization test for dengue 2 antibody and the remaining samples had antibodies to more than one dengue serotype. A good correlation was found between the presence of flavivirus and dengue IgG confirming that dengue virus had circulated in the past in the Solomon Islands.

Antibodies, Viral↗