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Biomedical subjects

J Baldwin

Publications and source records attributed to J Baldwin.

At least 73 records · Page 4Linked to original sources
PubMed1985

Treatment of essential hypertension: changes in blood pressure, echocardiography and electrocardiography on three therapeutic regimes.

Forty-three patients with essential hypertension were randomly allocated to one of the following treatment regimes; - atenolol, atenolol and hydralazine or methyl dopa. Blood pressure fell into the normal range at 3 months and was similar in all 3 groups. Blood pressure remained controlled over the period of study. M-mode echocardiography was assessed initially, at 3, 6 and 12 months. All groups showed a fall in the measured indices towards the normal range with a significant reduction in left ventricular wall thickness at 3 months in the methyl dopa group and left ventricular mass in the atenolol group alone of 6 months. In conclusion, no one treatment regime appeared to have sustained advantages over another and none of the groups showed any deterioration on echocardiographic criteria during the study.

Adult↗
PubMed1984

Heart-lung transplantation for irreversible pulmonary hypertension.

Combined heart and lung transplantation was carried out in 17 patients at Stanford University between March, 1981, and December, 1983. The recipients were between 22 and 45 years old. All patients had end-stage pulmonary hypertension; 10 had Eisenmenger's syndrome and the remaining 7, primary pulmonary hypertension. Five patients died within the first few postoperative weeks. The remainder are well between four weeks and 33 months from operation. The immunosuppressive protocol has consisted of cyclosporine with an initial course of rabbit antithymocyte globulin. Azathioprine also was given for the first two weeks and then was replaced with prednisone. Rejection, as diagnosed by cardiac biopsy, was treated with high doses of methylprednisolone. Modifications of technique that have developed include the removal of the recipient heart and lungs separately, and preservation of the lungs with a modified Collins' solution instead of a cardioplegic solution. Rejection occurred in 6 of the 12 survivors. Infections developed in 9 patients, but only one resulted in a fatal outcome (Legionella). Thus, the results of clinical heart-lung transplantation have been considerably superior to clinical efforts in lung transplantation. It is suggested that the combined operation is preferable for the following reasons: (1) all diseased tissue is removed, thus eliminating recurrent infection and ventilation/perfusion disparity; (2) transplantation of the entire heart-lung block preserves coronary-bronchial vascular anastomoses and makes airway dehiscence less likely; and (3) to date, diagnosis of rejection by cardiac biopsy has appeared to be a satisfactory method of diagnosing and treating pulmonary rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Clinical heart-lung transplantation.

Combined heart and lung transplantation was carried out in thirteen patients at Stanford University between March 1981 and May 1983. The recipients were between 22 and 45 years old. All patients were suffering from end-stage pulmonary hypertension; nine patients had Eisenmenger's syndrome; the remaining four were transplanted for primary pulmonary hypertension. Three patients died within one month of surgery. The remainder are well at between 22 months and three weeks from operation. The duration of stay in the hospital for the surviving patients ranged from 38 to 85 days. The immunosuppressive protocol has been essentially the same for all recipients, and has consisted of cyclosporine with an initial course of rabbit antithymocyte globulin (RATG) with azathioprine given for the first two weeks, and then replaced with prednisone. Rejection, as diagnosed by cardiac biopsy, was treated with pulses of methylprednisolone. Early complications included bleeding that necessitated reexploration (five patients); damage to the vagus, recurrent laryngeal, or phrenic nerves (three patients); and failure of the donor lungs (one patient). Modifications of technique that have developed include removal of the recipient heart and lungs separately, and preservation of the lungs with a modified Collins' solution instead of a cardioplegic solution. The results of this operation are considerably superior to clinical efforts in lung transplantation. The combined operation may be preferable for the following reasons: All diseased tissue is removed, thus eliminating recurrent infection, and also perfusion/ventilation disparity. Transplantation of the entire heart and lung block preserves coronary-tracheal vascular anastomoses and makes airway dehiscence less likely. Diagnosis of rejection by cardiac biopsy seems to be a satisfactory method of diagnosis and treatment of pulmonary rejection.

Adult↗
PubMed1983

Combined heart and lung transplantation.

Combined heart and lung transplantation was carried out in ten patients at Stanford University Medical Center between March, 1981, and December, 1982. All patients had end-stage pulmonary hypertension. 7 of them had Eisenmenger's syndrome and 3 primary pulmonary hypertension. 3 patients died within a month of operation, but the remaining recipients are well 2 months to 2 years after transplantation. The hospital stay of the survivors ranged from 38 to 85 days. All survivors have returned to normal activity. The results of heart and lung transplantation have thus been considerably superior to those reported previously for lung transplantation. It is suggested that cardiopulmonary replacement is suitable treatment for end-stage pulmonary hypertension with or without associated congenital heart disease and that its application to other forms of advanced pulmonary failure may be warranted.

Adult↗
PubMed1983

The control of smoking: smoking rate in designated smoking and no-smoking areas.

Unobtrusive measurements were taken over a 5-day period at three hospital areas designated as smoking permitted and three designated as no-smoking. A surprisingly high degree of compliance was observed in reported patient complaints or criticisms in regard to the controlled-smoking policy. The practical advantages of a comprehensive, hospital-wide sign program designating smoking and no-smoking areas are discussed.

Cooperative Behavior↗
PubMed1982

Multiple forms of octopine dehydrogenase in Strombus luhuanus (mollusca, gastropoda, strombidae): genetic basis of polymorphism, properties of the enzymes, and relationship between the octopine dehydrogenase phenotype and the accumulation of anaerobic end products during exercise.

Octopine dehydrogenase (ODH) is electrophoretically polymorphic in the gastropod mollusk Strombus luhuanus. The frequencies of the six electrophoretic phenotypes in the Heron Island population, together with the molecular weight values of 38,000 obtained for each of the three forms of the enzyme, demonstrate that the monomeric enzyme is encoded by three codominant alleles at a single locus. The purified allozymes are indistinguishable in terms of Km values for substrates, product inhibition by octopine and NAD, pH optima, and substrate inhibition by pyruvate. No statistically significant correlations were found between the ODH phenotype and the maximum activities of ODH or alanopine dehydrogenase, the capacity for anaerobic muscle work, or the accumulation of octopine or strombine/alanopine during exercise. It would appear that the ODH allozymes may be functionally equivalent both in vitro and in vivo.

Alleles↗
PubMed1982

Three-years' experience in a regional burn center with burns of the eyes and eyelids.

A retrospective three-year study of lid and ocular burn injuries in a regional burn center revealed no major complications. The management program was based on cooperation between the burn unit and ophthalmological staff and included: 1. A high index of suspicion for eye injuries of the burned patient; 2. Early ophthalmologic consultation and examination; 3. Aggressive early treatment; 4. Rigorous follow-up and re-examination; and 5. Multiple and frequent grafting of lids, as needed.

Burns↗
PubMed1979

Response perseveration in rats exposed to alcohol prenatally.

Pregnant female rats consumed liquid diets containing either 35, 17, or 0% of the total calories as ethanol. Offspring of these females were tested for spontaneous alternation at 21 days of age and for reversal learning in a T-maze shock-escape paradigm at 20--21 days of age. In the spontaneous alternation test, rats exposed to alcohol prenatally took more trials than controls to enter the goal compartment opposite to that initially entered. In the T-maze escape study, alcohol-exposed offspring made more mistakes prior to criteron and more mistakes per trial than controls when the previously incorrect goal was made safe during reversal learning. In both studies linear dose-response functions were found. Furthermore, there was a significant tendency for the within-group variabitliy to increase as the level of prenatal exposure increased, perhaps indicating that the incidence as well as the severity of behavioral dysfunction was dose dependent. The results are interpreted in terms of a delay in the development of a central inhibitory system.

Animals↗
PubMed1978

Rules for ring closure.

The ease of formation of cyclic structures shows some regularity which can be described by a set of 'rules' for ring closure. The restrictions on the endocyclic transfer of groups due to SN2 displacements having linear transition states are exemplified by studied on a biogenetic type synthesis of penicillin and, more generally, on the endocyclic attack of a nucleophile attached by a linking chain to an enone or polarized double bond. The formation of five-memebered rings is considered. In base, enones such as 4-hydroxy- and 4-amino-2-methylenebutanoates close exocyclically to give the corresponding five-membered lactones and lactams, respectively. Hydroxymethyl vinyl ketones, however, do not cyclize in base. In strong acid, hydroxy-enones close endocyclically to five-membered ring, as in the formation of cyclic ethylene ketals from acetone and ethanediol. The endocyclic closure of nucleophilic centres to polarized double bonds to give five-membered rings is impeded by restrictions of geometry; these restrictions can be overcome in acid through the generation of oxonium or protonated forms.

Chemical Phenomena↗
PubMed1977

The mutagenicity of methylbenzylnitrosamine and its alpha-acetoxy derivatives.

Biological activity of the alpha-acetoxy derivatives of methylbenzylnitrosamine was evaluated using tester strains of Salmonella typhimurium. Compound III, oxidized on the benzyl moiety, was more toxic and more mutagenic than Compound IV, oxidized on the methyl side chain. Compound IV was weakly toxic and was non-mutagenic at the concentrations tested. The presence or absence of the uvrB repair system had no effect on the toxicity of either Compound II or IV. Neither the alpha-oxidized compounds nor the parent nitrosamine reverted the frameshift mutants. As a mutagen, Compound III was approximately as active as N-nitroso compounds not requiring metabolic activation, more active than alpha-acetoxy dialkylnitrosamines and less active than the cyclic alpha-acetoxynitrosopyrrolidine.

Carcinogens↗