Medical care in a tropical national reference and teaching hospital: outline study of cost-effectivenees.

During a 28-day prospective audit the cost-effectiveness of treatment in three types of medical wards in a large tropical teaching hospital was assessed. Patients with chronic diseases such as rheumatic heart disease were more expensive to treat than those with acute, curable illnesses such as malaria. It was concluded that the cost of providing treatment could not be reduced without affecting standards of medical care. The expense of running such a hospital might also be justified by its importnat function as a teaching hospital.     

Inflammatory cells in solid murine neoplasms. IV. Cytolytic T lymphocytes isolated from regressing or progressing Moloney sarcomas.

Highly purified suspensions of intratumoral T lymphocytes, recovered 11 and 13 days after induction of regressing or progressing Moloney sarcomas, were compared in their ability to lyse specifically the MSC cells used for tumor induction. Cytolytic activity, expressed in terms of lytic units/10(6) T cells, was similar for intratumoral T cell suspensions obtained 11 days after induction of either regressing (3.1 +/- 1.3 LU/10(6) T cells) or progressing (4.3 +/- 1.8) neoplasms. By 13 days post-induction, regressing tumors contained T lymphocytes with an increased cytolytic activity (11.1 +/- 4.5) whereas those from progressing tumors were strikingly less able to kill MSC cells (less than or equal to 0.2). This dramatic loss in cytotoxicity could not be attributed to errors associated with the enzymatic disaggregation method, inhibition by copurified endogenous tumor cells, or immunosuppression induced by viral infection. The changes in functional activity of intratumoral T lymphocytes from the two types of sarcoma appeared to be correlated with the stage of neoplasia. In this model system, cytolytic activity of T lymphocytes increased during spontaneous tumor regression whereas losses in cytotoxicity occurred coincident with the onset of inexorable progression.     

Influence of phage T3 and T7 gene functions on a type III(EcoP1) DNA restriction-modification system in vivo

Summary The ocr ⁺ gene function (gp 0.3) of bacteriophages T3 and T7 not only counteracts type I (EcoB, EcoK) but also type III restriction endonucleases (EcoP1). Despite the presence of recognition sites, phage DNA as well as simultaneously introduced plasmid DNA are protected by ocr ⁺ expression against both the endonucleolytic and the methylating activities of the EcoP1 enzyme. Nevertheless, the EcoP1 protein causes the exclusion of T3 and T7 in P1-lysogenic cells, apparently by exerting a repressor-like effect on phage gene expression. T3 which induces an S-adenosylmethionine hydrolase is less susceptible to the repressor effect of the SAM-stimulated EcoP1 enzyme. The abundance of EcoP1 recognition sites in the T7 genome is explained by their near identity with the T7 DNA primase recognition site.Abbreviations d.p.m. decompositions per min - EcoB, EcoK, EcoP1, EcoP15, EcoRII, EcoR124, HinfIII restriction endonucleases coded by Escherichia coli strains B or K, E. coli plasmids P1, P15, RII or R124, and Haemophilus influenzae Rf 232, resp. - e.o.p. efficiency of plating - gp gene product (in the sense of protein) - m.o.i. multiplicity of infection (phage/cell) - ocr ⁺ gene function which overcomes classical restriction - p.f.u. plaque-forming units - SAM S-adenosylmethionine - sam ⁺ gene function with S-adenosylmethionine-cleaving enzyme (SAMase) activity - UV ultraviolet light Dedicated to Professor Konstantin Spies on the occasion of his sixtieth birthday     

Sensitivity of Escherichia coli acrA mutants to psoralen plus near-ultraviolet radiation

The sensitivity to psoralen plus near-ultraviolet radiation (PUVA) was compared in a pair of E. coli strains differing at the acrA locus. Survival was determined for both bacteria and phage lambda. AcrA mutant cells were 40 times more sensitive than wild type to the lethal effect of PUVA. Free lambda phage exposed to PUVA survived as well when plated on acrA mutants as on wild type. In contrast, prophage lambda CI857 ind carried in lysogenic acrA strains was hypersensitive to PUVA. The enhanced sensitivity of bacterial and lambda DNA, when inside acrA cells, was paralleled by an increased photobinding of radiolabelled psoralens in the mutant. Binding was increased specifically to DNA rather than to nucleic acids in general. The difference in psoralen-binding ability determined by the acrA gene persisted after permeabilizing treatment of the cells. The results suggest that the acrA mutation causes an alteration specifically in the environment of the cellular DNA so as to allow increased intercalation and photobinding of psoralens.     

T cell responses to select Ia determinants using the I-A mutant mouse strain B6.C-H-2bm12

The T cell repertoire of B6.C-H-2bm12 mice (an I-A mutant mouse strain) to wild-type Iab antigens was investigated using both secondary proliferative cultures and cloned T cell lines. Because bm12 mice have a gain-loss mutation of their gene encoding the Ia beta-chain polypeptide, bm12 anti-B6 T cell responses are specific for the select component of Iab specificities that was lost as a result of the mutation. Although stimulator cells bearing Iab antigens elicited the strongest responses, Iaq, d, and s antigens also resulted in reproducible stimulations of these bm12 anti-B6-primed T cells. Cloned T cell lines isolated from bm12 anti-b6 cultures revealed similar findings, with most clones recognizing determinants unique for Iab antigens; however, clones showing cross-reactions with Iad and/or q were also selected. Using F1 hybrid responder T cells (mutant x cross-reactive strain), we further dissected this cross-reactivity into several distinct cross-reactive determinants. Because bm12 mice lack the serologically defined Ia differentiation antigen W39, T cell recognition of this determinant was investigated by using bm12 anti-B6-primed cells. Stimulation by Ia.W39+ cells was appreciably better than by Ia.W39- (Xid-defective) cells, suggesting that bm12 T cells recognize an Xid-regulated, W39-like Ia differentiation antigen.     

Seasonal changes in adventitious root formation in hypocotyl cuttings of Pinus sylvestris: Influence of Photoperiod during stock plant growth and of indolebutyric acid treatment of cuttings

Seedlings of Pinus sylvestris were grown for 6 weeks under natural light conditions in a temperature controlled environment room. Cuttings from these plants were rooted in tap water or in indolebutyric acid (IBA) solutions for 60 days at an irradiance of 16 W m^-2. Experiments were performed at 3-week intervals during two growth seasons. — Seasonal changes in root formation were found in control cuttings as well as in IBA treated cuttings. The number of roots and the percentage of cuttings that rooted were high during early spring and autumn. During the summer period hardly any roots were formed. Stimulation of root formation by IBA occurred manily during spring and autumn when cuttings already possessed the ability to form roots. — The influence of photoperiod during stock plant growth was also investigated. Shorter photoperiod resulted in an increase in the number of roots and rooting percentage. The period during summer where rooting was inhibited under natural light conditions was considerably shortened when stock plants were grown at a photoperiod of only 4 h. The results demonstrate the importance of the growing conditions for stock plants for subsequent root formation. The results are discussed with special reference to the role of irradiance.     

Congenital malformations in Utah

The rate of malformed children in Utah of 11.7 per 1,000 liver births, derived from 128,857 birth certificates, ws not high compared with other non-Utah studies. Rates of selected malformations also were not high. The rate of malformed children varied by county of residence. San Juan County reported the highest percentage of mothers receiving late or infrequent prenatal care, the lowest mean level of public education, and the highest rate of malformed children in the state. The rate was not significantly associated with the large population of Indians residing in that county since by controlling for residence, the variation by race was eliminated. The overall rate was positively associated with maternal age rimarily due to an increased frequency of Down's syndrome. The impact of the "maternal age effect" on the state malformation rate, however, was not large. By controlling for maternal age, the slight association between increased rate of malformed children and increasing birth order was eliminated. The rate of malformed children was higher for parents having a low level of education, infrequent prenatal care, or who were not married. There was also a strong negative association of birth weight with the rate of malformation. Analysis of rates of selected malformations suggested that the low birth weight was a sequela to intrauterine growth retardation caused by severe congenital malformation. The validity and etiologic implications of these results await further investigation.     

A new human T-cell differentiation antigen: Unexpected expression on chronic lymphocytic leukemia cells

Monoclonal antibody 10.2 reacts with a monomorphic antigen expressed on the surface of virtually all thymocytes, as well as thymus-dependent lymphocytes in the peripheral blood and bone marrow. In contrast, antibody 10.2 did not react with normal peripheral blood B cells, monocytes, or the non-T-cell fraction of bone marrow. This complement fixing IgG2a antibody also reacted with extablished leukemic T-cell lines, but not with cell lines of either normal or malignant B-cell origin. Similarly, when tested against acute leukemia blasts, the 10.2 antibody reacted with those from patients with T-cell acute leukemia, but not with those from patients with acute null cell or non-lymphocytic leukemia. An unexpected exception to this pattern was the reaction of 10.2 antibody with leukemic cells from patients with B-cell type chronic lymphocytic leukemia. Immune precipitates formed with 10.2 antibody and detergent lysates of radiolabeled T-cells contained three polypeptides with molecular weights of 65 000, 55 000, and 50000 daltons. It has not been determined whether all three of these polypeptides contain the 10.2 antigenic determinant, or whether these proteins represent a multimeric antigen complex.PJM is a Junior Faculty Clinical Fellow of the American Cancer Society.     

Measurement and analysis of gas exchange during exercise using a programmable calculator

Although exercise testing is useful in the diagnosis and management of cardiovascular and pulmonary diseases, a rapid comprehensive method for measurement of ventilation and gas exchange has been limited to expensive complex computer-based systems. We devised a relatively inexpensive, technically simple, and clinically oriented exercise system built around a desktop calculator. This system automatically collects and analyzes data on a breath-by-breath basis. Our calculator system overcomes the potential inaccuracies of gas exchange measurement due to water vapor dilution and mismatching of expired flow and gas concentrations. We found no difference between the calculator-derived minute ventilation, CO2 production, O2 consumption, and respiratory exchange ratio and the values determined from simultaneous mixed expired gas collections in 30 constant-work-rate exercise studies. Both tabular and graphic displays of minute ventilation, CO2 production, O2 consumption, respiratory exchange ratio, heart rate, end-tidal O2 tension, end-tidal CO2 tension, and arterial blood gas value are included for aid in the interpretation of clinical exercise tests.