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Biomedical subjects

M A Baker

Publications and source records attributed to M A Baker.

At least 127 records · Page 7Linked to original sources
PubMed1981

Effects of dehydration on thermoregulation in cats exposed to high ambient temperatures.

Measurements of evaporative water loss (EWL), metabolic rate (MR), body core temperature (Tc), and respiratory rate (RR) were made in nine hydrated cats exposed to several high ambient temperatures. Measurements were made in animals hydrated ad libitum and during progressive dehydration. At 43 and 40 degrees C, no significant change in EWL occurred during dehydration. At 38 and 35 degrees C, EWL in animals dehydrated for 4 days was reduced to about 50% of hydrated levels. Reductions in RR correlated highly with reduced EWL, suggesting that control of evaporation in dehydrated cats is dependent largely on control of RR. Significant elevations in Tc occurred in dehydrated animals at 43, 40, and 38 degrees C, and an insignificant upward trend was observed at 35 degrees C. Multiple linear regression analysis of data for EWL, Tc, and level of dehydration indicates that dehydration reduces the evaporative response to elevations in Tc and suggests that a change in the sensitivity of the thermoregulatory system is occurring. A similar analysis for MR, Tc, and level of dehydration shows that dehydration results in a lower MR at a given Tc. Changes in MR, corrected for body temperature, during dehydration are principally related at altered ventilatory energy expenditure. A model has been formed for estimating the metabolic cost of ventilation in the cat.

Animals↗
PubMed1981

Combined modality treatment of small cell carcinoma of the lung.

Ninety patients with extensive and 61 with limited small cell carcinoma of the lung were treated with three courses of intravenous chemotherapy (cyclophosphamide, doxorubicin hydrochloride, and vincristine sulfate) followed by radiotherapy to intrathoracic disease, and a second three-drug oral combination consisting of lomustine, procarbazine, and methotrexate for one year. Among the 147 patients who were evaluated, 55 of 66 (83%) with limited disease and 53 of 81 (65%) with extensive disease showed response after three courses of chemotherapy. The complete response rate in patients with limited disease prior to radiotherapy was 24%, but increased to 58% when evaluated following radiotherapy. The median survival was 47 weeks for patients with limited disease and 36 weeks for those with extensive disease. A 24% two-year survival is projected for complete responders. Important prognostic factors for survival are performance status, extent of disease, and sex, with female subjects doing somewhat better than male subjects. Among patients with limited disease, 45% failed within the CNS despite the use of chemotherapeutic agents that cross the blood-brain barrier. The initial induction regimen and radiotherapy were well tolerated; the oral three-drug combination was more toxic and did not prevent CNS metastases.

Adult↗
PubMed1980

Myeloblastic and lymphoblastic markers in acute undifferentiated leukemia and chronic myelogenous leukemia in blast crisis.

Blast cells were obtained from 17 patients with acute undifferentiated leukemia and 13 patients with chronic myelogenous leukemia in blast crisis. The blasts were tested with anti-i serum in cytotoxicity tests and with antisera to myeloblastic leukemia-associated antigens in immunofluorescence tests. The terminal deoxynucleotidyl transferase (TDT) content of the blasts was also measured. Lymphoblasts react strongly with anti-i, do not react with anti-myeloblast serum, and have high levels of TDT; myeloblasts react weakly with anti-i, do not react with anti-myeloblast serum, and have very low levels of TDT. Of the 17 patients with acute undifferentiated leukemia, there were six with blasts which reacted like lymphoblasts, six with blasts which reacted like myeloblasts, and five with blasts bearing different combinations of these lymphoblastic and myeloblastic markers. Eight of the 11 patients with lymphoblastic or mixed lymphoblastic-myeloblastic markers, but only one of the six with myeloblastic markers, achieved complete or partial remission in response to therapy. Thus, in acute undifferentiated leukemia, classification of blasts with these markers may be of prognostic value. Of the 13 patients with chronic myelogenous leukemia in blast crises, the markers were concordant (for myeloblasts) in only two cases. Three of the 13 patients had TDT-positive blasts, but the reactions of these cells with anti-i and with anti-myeloblast serum differed from those seen with lymphoblasts from patients with acute lymphoblastic leukemia. Although the cell involved in "lymphoid" blast crisis of chronic myelogenous leukemia is similar in many respects to that involved in acute lymphoblastic leukemia, these cells are not identical.

Adult↗
PubMed1980

Serologic characterization of a monkey antiserum to human leukemic myeloblasts.

We have raised a monkey antiserum that is selectively reactive with human leukemic myeloblasts by immunization with a glycoprotein antigen (AMLSGA) released from myeloblasts in short-term culture. Antimyeloblast activity can be demonstrated using complement-dependent cytotoxicity or indirect immunofluorescence. Selective antimyeloblast activity is retained following absorption with leukemic lymphoblasts or lymphocytes, nonleukemic lymphocytes, neutrophils, or mononuclear cells from nonleukemic bone marrow. Anti-AMLSGA antisera are not reactive with B-cell-enriched cell populations, and antaimyeloblast activity is not reduced by absorption with Ia-positive cells. Anti-AMLSGA is a useful reagent for identification of human leukemic myeloblasts.

Animals↗
PubMed1979

Early diagnosis of relapse in acute myeloblastic leukemia: Serologic detection of leukemia-associated antigens in human marrow.

We tested serial bone-marrow samples from 47 adults with acute myeloblastic leukemia in remission for reactivity with heteroantiserums to leukemia-associated antigens, to determine whether imminent relapse could be detected in patients with acute leukemia. Of 26 patients who relapsed by standard morphologic criteria, 21 had increased immunoreactivity of bone marrow for one to six months (mean, 3.7 months) before relapse. High concordance was observed between a positive test and relapse during the period of study (chi-square = 27.53, P less than 0.001). The median time to relapse after a positive test was four months, as compared with the median remission duration of 19 months for the whole group (P less than 0.02, Peto's log-rank analysis). Serologic detection of leukemia-associated antigens in marrow may be a reliable indicator of imminent relapse in acute myeloblastic leukemia.

Animals↗
PubMed1979

Oral administration of BCG as an adjuvant to surgical treatment of carcinoma of the bronchus.

A controlled clinical trial of the value of bacille Calmette--Guérin (BCG) vaccine given orally to patients with resectable carcinoma of the lung was conducted in 18 centres across Canada. A total of 308 patients were included in the analysis, 155 in the BCG group and 153 in the control group. The two groups were similar at the time of admission to the trial. BCG (120 mg) was given orally at weekly intervals for 1 month, every 2 weeks up to 3 months and then every 3 months until the total duration of therapy was 18 months. Over a 3- to 5-year follow-up period after the operation there was no difference in survival between the two groups, the proportion alive at 2 years being 61% in the BCG group and 58% in the control group. There was also no evidence of differences in the time to the detection of recurrent or metastatic disease or in the distribution of such disease. An analysis of prognostic factors confirmed the poor survival associated with histologically confirmed lymph node involvement. It may be concluded that no favourable effect from the oral administration of BCG was demonstrated.

Adjuvants, Immunologic↗
PubMed1979

Erythroleukemia in a renal transplant recipient.

A 53-year-old male developed acute erythroleukemia three years after renal transplantation. He had received three years of immunosuppressive therapy with azathioprine. A preleukemia phase associated with chromosome abnormalities was recognized. Azathioprine has been associated with chromosome abnormalities. The chronic stimulation of an abnormal erythroid clone by transplantation may have hastened the development of erythroleukemia.

Azathioprine↗
PubMed1978

Comparison of the adjuvant effect of three BCG preparations in mice.

Three preparations of BCG, currently in use for clinical trials in cancer, were tested for relative potency as an immunological adjuvant. Using a lymphocyte trapping assay, Pasteur Institute BCG was shown to be a more effective adjuvant than the Tice strain or the Glaxo preparation of BCG.

Adjuvants, Immunologic↗
PubMed1978

Isolation and partial characterization of radioiodinated myeloblastic leukemia-associated cell surface glycoprotein antigen.

Peripheral blood myeloblasts from five patients with acute myeloblastic leukemia and peripheral remission leukocytes from two of these patients were radiolabeled by the lactoperoxidase-catalyzed surface radioiodination technique and incubated in a nutrient medium at 37 degrees. Radioactive materials shed from viable cells into the supernatant at 24 hr were purified by gel filtration and by DEAE-cellulose chromatography. The radiolabeled leukemic cells shed relatively few molecular species into the culture medium. The DEAE-cellulose eluate usually contained one major peak in which radioactivity and protein levels were coincident; the molecular weight of this compound was 350,000 to 400,000, and it contained carbohydrate as well as protein. Glycoprotein shed from leukemic cells was specifically reactive in a coprecipitation assay with defined antimyeloblast alloantisera obtained from leukemic patients receiving immunotherapy. No reaction was seen with antisera directed against HLA or B-cell antigens. Material shed from remission cells did not coprecipitate with antileukemic antisera. The isolation of radioactively labeled antigen derived from myeloblasts may ultimately allow the monitoring of human antigen levels in leukemic blood by radioimmunoassay.

Antigens, Neoplasm↗