Lysosomes and lysosomal enzyme activity in the regenerating planarian; evidence in support of dedifferentiation.
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Acid Phosphatase↗
Biomedical subjects
C E Bennett
Publications and source records attributed to C E Bennett.
Electron microscope studies of Fasciola hepatica. 13. Fine structure of newly excysted juvenile.
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Animals↗
Cryopreservation of human lymphocytes: a brief review and evaluation of an automated liquid nitrogen freezer.
Successful cryopreservation of human lymphocytes has been previously described. Cryopreserved lymphocytes are useful for a variety of in vitro immunologic studies. This study was performed to determine the applicability and/or advantages of using a programmable freezing system, and compares glycerol versus dimethyl sulfoxide (DMSO) at varying concentrations on post-thaw viability, E-rosetting and immunoglobulin fluorescence. Prefreeze T and B lymphocyte percentages were determined. Cells were then frozen in varying concentrations of glycerol and DMSO. Optimum cryoprotectant type and concentration was determined. Lymphocytes from seven individuals were frozen by the batch method in a mechanical freezer and with the automated liquid nitrogen injection system. Data on post-thaw T and B percentages and viability revealed 10% DMSO and liquid nitrogen control freezing method at 1 C/minute as the best conditions for lymphocyte preservation as reflected by post-thaw in vitro testing.
Blood Preservation↗
Alterations of lymphocyte responsiveness in Guillain-Barré syndrome. Effects of plasma exchange.
Various antibodies and immune complexes have been demonstrated in patients with Guillain-Barré syndrome (GBS). These factors may be part of the pathogenesis of the disease process through immune complex deposition and/or suppression of the immune system. Four patients with typical GBS were treated by plasma exchange. Aliquots from the first 100 ml of plasma removed from each patient were incubated with cultures of normal human peripheral lymphocytes that subsequently were exposed to mitogens, followed by incubation with tritiated thymidine. A decrease (p less than 0.001) in response to each of the mitogens was noted after incubation with patient plasma. Peripheral lymphocytes were taken from the patients before and after plasma exchange. An increase (p less than 0.01) in DNA synthesis following mitogen exposure was observed after plasma exchange in each patient. All patients exhibited subjective and objective clinical improvement. Plasma exchange for GBS appeared to remove a lymphocyte suppressor factor, which was characterized by column fractionation. The suppressor factor was determined to be a substance of approximately 10,000 to 12,000 daltons that reproducibly decreased the responsiveness of normal lymphocytes to mitogens.
Adult↗
How a hospital E.R. can deal with radiation.
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Emergency Service, Hospital↗
Immunity during pregnancy: lymphocyte subpopulations and mitogen responsiveness.
Many hypotheses have been proposed to explain the alteration of maternal immune status that allows the fetus to escape rejection. Published data using monoclonal antibodies have stated that there are small variable reductions in circulating T-lymphocytes and little or no change in helper-to-suppressor ratios. Specific decreased levels of helper T-cells have been claimed by other workers. Our laboratory has previously reported alterations in tritiated thymidine uptake (3H-TdR) and HLA antibodies during pregnancy. The present study evaluates total T-cells, lymphocyte T-cell subsets, helper-to-suppressor ratios of T-cells, B-cells, and lymphocyte blast transformation (LBT) throughout pregnancy. These lymphocyte measurements were compared to hormonal changes occurring during pregnancy to determine whether or not hormonal levels have a significant correlation on the maternal immune response during gestation. Data from 100 women revealed no significant alteration of total T-cells or T-cell subsets during pregnancy or after parturition, as measured by monoclonal antibodies. Helper-to-suppressor ratios were within normal limits. B-cells showed a significant decrease (P less than 0.001) during the postpartum period. There was decreased lymphocyte responsiveness to mitogenic stimulation by phytohemagglutinin-P (PHA-P), concanavalin-A (CON-A), and pokeweed mitogen (PWM) in the first, second and third trimesters (P less than 0.01). The mechanisms of fetal protection from maternal immune recognition remain obscure.
Adolescent↗
B and T lymphocytes: methodology and normal ranges.
B and T lymphocytes separation by use of various cell markers had been previously described. These differential lymphocyte subpopulation counts have been helpful in elucidating immunodeficiency, lymphoproliferative and other disease states. Expanding clinical utility has moved these assays into the general laboratory for routine determination. Specific methodology for differentiation of B and T cell subpopulations is described. The mean T cell population is 68.1 percent +/- 4.2 and the mean B cell population is 8.4 percent +/- 2.1 for 30 ambulatory normals. A bi-modal distribution of T and B lymphocyte cell lines is noted in a family with a high incidence of carcinoma. Preliminary data on patients in the diabetic clinic of the Medical University of South Carolina shows a statistically significant difference in the T cell population of diabetics versus normal.
B-Lymphocytes↗
T and B lymphocyte subpopulations in black patients with diabetes mellitus.
A modified method of assaying T and B lymphocytes was used to investigate the T and B cell subpopulations in black patients with diabetes mellitus. Thirty-eight black diabetic patients were compared to 55 non-diabetic patients (20 blacks and 35 whites). The diabetic patients had an increased T-lymphocyte population (73.4 percent +/- 7.9) as compared to the black controls (66.2 percent +/- 1.7, p less than 0.001) and the white controls (68.1 percent +/- 3.5, p less than 0.001). Black non-diabetic patients had a decreased T-cell population compared to the white non-diabetic patients. This suggests race was not an explanation for the increased T-cell percentages observed in the diabetic population. No difference was demonstrated in the percentage of B-lymphocyte subpopulations between any group.
Adult↗
Antitumor effects of abrin and ricin used singly and in combination with cisplatin.
Abrin, ricin, and cisplatin produced significant increases in survival times of mice inoculated with 10(6) Ehrlich ascites carcinoma or L1210 leukemia cells 24 hours prior to treatment. Combinations of abrin or ricin with cisplatin produced markedly synergistic action in prolonging survival times of mice bearing cell line A of L1210 leukemia. For example, a dosage of 1.33 micrograms per kg abrin produced a 40 percent increased length of survival (ILS) and 2.5 mg per kg of cisplatin produced a 45 percent ILS while a combination of the two agents resulted in a 229 percent ILS and produced 60-day survivors or "cures" in 20 percent of the mice treated. Similar combinations of abrin or ricin with cisplatin also produced significant additive or synergistic increases in survival times of mice bearing cell line B of L1210 leukemia or Ehrlich ascites carcinoma. Aged solutions of abrin and ricin appeared to be less toxic, but have similar antitumor effect alone or in combination with cisplatin, than freshly prepared solutions.
Abrin↗
Lymphocyte blast transformation and peripheral lymphocyte percentages in patients with sickle cell disease.
Twenty patients with sickle cell disease (14 black females and 6 black males, mean age 31.5 +/- 9.3) were studied by quantitating peripheral T and B lymphocyte percentages and measuring lymphocyte blast transformation (LBT) in response to phytohemagglutinin-P, concanavalin-A and pokeweed mitogen. Compared to normal black controls (19 black females and 1 black male, mean age 32.0 +/- 9.2 years) sickle cell patients had decreased T lymphocytes (50.2 percent +/- 6.2 compare; to 66.2 percent +/- 1.7) and increased B lymphocytes (17.0 percent +/- 3.4 compared to 7.7 percent +/- 1.1). Sickle patients exhibited decreased LBT to all three mitogens.
Adult↗
B and T lymphocytes: quantitation, function, and clinical applicability.
Methodologies for T and B lymphocyte quantitation, lymphocyte blast transformation (LBT) and carbohydrate (CHO) metabolism are important for assessing host lymphocyte response in the clinical laboratory. Modifications of methods for each of these techniques are presented. Results from studies of normal ambulatory adults, patients with diabetes mellitus, sickle cell disease and hyperlipidemia are reported. LBT of normal lymphocytes before and after ethanol exposure are examined. LBT during pregnancy is evaluated. T cell populations are abnormally high in black diabetics and decreased in patients with sickle cell anemia. B cell subpopulations are increased in patients with sickle cell anemia. LBT responses are decreased in maturity onset diabetes, during pregnancy and in patients with sickle cell disease. Ethanol in amounts attainable during human consumption results in significantly decreased LBT response. CHO metabolism (especially hexose monophosphate shunt [HMPS] and HMPS by pentose sugar recycling) is abnormal in diabetic lymphocytes. The low HMPS activity is partially reversible by treatment with prostaglandin synthetase inhibitors. Information related to lymphocytes in normal states remains to be collected by further clinical application of these techniques of quantitation and in vitro function.
Adult↗
Effects of insulin on phytohemagglutinin-P, concanavalin-A, and pokeweed mitogen in diabetic and nondiabetic lymphocytes.
Blast transformation of lymphocytes from diabetics and nondiabetics was evaluated after adding insulin at various concentrations. Responses to phytohemagglutinin-P (PHA-P), concanavalin-A (CON-A) and pokeweed mitogen (PWM) were measured in the presence of exogenous insulin added in physiologic increments of 0, 10, 20, 30, and 40 microunits of activity per ml of culture medium. A modified method utilizing heparinized whole blood was used. After a four day incubation period, 3H-TdR uptake was evaluated and used as the index of stimulation. A standard pooled z test for comparison of 3H-TdR uptake showed a decrease in blast transformation of diabetic lymphocytes compared to nondiabetic lymphocytes to the mitogens PHA-P (p less than 0.01), CON-A (p less than 0.01), and PWM (p less than 0.01). Added insulin increased the diabetic lymphocyte blast transformation response to each of the mitogens. Blast transformation in diabetics never reached the leve of blast transformation in nondiabetics. It is hypothesized that there is a cellular defect in either membrane receptors or intracellular metabolic pathways which accounts for the decrease in diabetic lymphocyte blast transformation.
Adult↗
Issues regarding data on race and ethnicity: the Census Bureau experience.
In this paper, the authors describe some of the complexities of collecting and presenting data on race and ethnicity based on the experiences of the Bureau of the Census. Different methods of data collection, different content and format of questions, and different definitions make it difficult to collect consistent race and ethnic data across data systems. The Bureau of the Census experiences have shown that changing ethnic self-identity and concepts, intent of the question, consistency of reporting, and the classification of persons of mixed racial parentage affect the quality of the data. These are some of the issues that must be addressed as statistical agencies and researchers seek to provide comparable race and ethnic data.
Data Collection↗