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Biomedical subjects

G J Marshall

Publications and source records attributed to G J Marshall.

9 recordsLinked to original sources
PubMed1992

Graft perforations favor osteoinduction. Studies of rabbit cortical grafts sterilized with ethylene oxide.

The healing of freeze-dried, ethylene oxide sterilized, segmental, allogenic cortical bone grafts was investigated in 15 rabbits using a 2-cm ulnar diaphyseal defect. Five different groups of bone grafts were evaluated: 1) unperforated undemineralized, 2) perforated undemineralized, 3) unperforated demineralized, 4) perforated demineralized, and 5) perforated demineralized grafts enclosed by silicone rubber (Silastic) sheets. There were 3 animals in each group. At 18 days, the study was terminated, and the implants were examined using radiographs and qualitative histologic preparations. We observed that healing of perforated demineralized bone was superior to unperforated demineralized bone, that undemineralized bone was partially sequestered in reactive lacunae, and that perforations in demineralized bone became centers of osteoinduction. Demineralized bone sterilized with ethylene oxide by this method vigorously formed new bone.

Animals↗
PubMed1992

Bone response to invading tumors with spindle cell components: a report of findings in two patients.

Two case studies are presented in which quantitative bone histomorphometry is used to analyze bone changes in adult patients with diagnosed spindle cell sarcoma. Three tumor-involved sites and one noninvolved site from the iliac crest of patient 1 were evaluated. In the involved sites the percentage trabecular bone volume (11.0%) and the number of osteoblasts (0.6 cell/mm2) were significantly reduced, osteoid volume was significantly increased (8.1%), and woven osteoid was present. The total eroded surface (6.8%) was also significantly increased. In the noninvolved site the number of osteoblasts was decreased and both the percentage eroded and percentage osteoclast surfaces were increased. In the femoral epicondyle specimen from patient 2 the number of osteoblasts was 27.0 cells/mm2, percentage osteoid volume was 18.4%, percentage osteoid surface was 62.9%, and osteoid thickness was 20.0 microns. In tumor-involved sites in both patients indices of active bone resorption were similar and normal. These two case studies indicate that (1) distinctive morphologic changes occur in bone invaded by spindle cell sarcoma, and that (2) changes affect bone formation to a greater extent than bone resorption. Bone alterations are probably local in nature and related to the extent and duration of tumor invasion and the influence of local tumor factor(s).

Adult↗
PubMed1978

Effect of operation on B and T lymphocyte counts.

Preoperative and postoperative studies of peripheral B and T lymphocyte counts were accomplished in 21 patients. Diagnoses included 10 carcinoma of the breast, 3 sarcoma, and 8 benign diseases. On postoperative day one and two, an increase in B-cell percentage was observed in the majority of patients tested. However, there was a decrease in total lymphocyte count and fast-reacting T lymphocyte numbers on postoperative day one, especially in patients who had intraabdominal operations. All the lymphocyte counts returned to preoperative range within one week. Pertinent reports in the literature were reviewed and discussed.

Adult↗
PubMed1978

Student-constructed examination items.

Student-written items were compared with teacher-written items on an objective examination given to first year medical students. While student scores were higher on the student-written items than on teacher-written items, there was a positive correlation between the scores. Student items did not differ from teacher items in the course, according to student ratings of emphasis. As a by-product of this study, correlations were found which suggest that student scores on an item often reflect the degree of teaching emphasis given the content area of the item rather than the inherent difficulty of the content. It is suggested that further research is needed to determine whether students learn through the process of writing examination items. Therefore, if the process proves to be educational, this study indicates that it will be feasible to incorporate the student-constructed items in examinations.

California↗
PubMed1977

Randomized clinical trial of cystosine arabinoside and 6-thioguanine in remission induction and consolidation of adult nonlymphocytic acute leukemia.

One hundred and forty-seven adults with acute nonlymphocytic leukemia were randomized to one of two treatment regimens utilizing cytosine arabinoside and 6-thioguanine. In regimen A the drugs were administered every 12 hours until marrow cellularity was reduced by at least 50%. In regimen B the drugs were administered every 12 hours for 5 days with five to 7 days rest intervals between courses. Decisions to continue or reinstitute therapy were based solely on marrow cellularity and marrow ratings. The overall response in referee-verified cases in both groups was similar (41%); regimen B proved to be the easier protocol to administer but required greater support. Younger patients or those with an initial high hemoglobin count responded best to these drug regimens. Only 36% of our patients experienced severe marrow hypoplasia (i.e., a 75% or greater reduction in marrow cellularity) prior to complete remission, suggesting that cytosine arabinoside and 6-thioguanine in combination may selectively suppress leukemic cells while sparing normal hematopoietic elements.

Acute Disease↗
PubMed1977

Peripheral B- and T-lymphocyte counts in patients with sarcoma and breast carcinoma.

Peripheral B- and T-lymphocyte counts were studied in 50 patients before they received any therapy for their conditions: 16 had carcinoma of the breast; 8 soft tissue sarcoma; and 26, benign disease. Among 11 males, the six patients with advanced soft tissue sarcoma had significantly lower percentages of T lymphocytes than five patients with benign conditions. And six female patients with advanced breast cancers had significantly higher numbers of B lymphocytes than the 10 patients with early breast malignancies. Pertinent reports in the literature were reviewed and discussed. Presently, the clinical and prognostic values of quantitative study of T and B lymphocytes remain to be defined.

Adolescent↗