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Biomedical subjects

M Green

Publications and source records attributed to M Green.

At least 667 records · Page 37Linked to original sources
PubMed1983

Effects of temperature on Vitalograph spirometer readings.

Spirometric variables were obtained from nine symptomless subjects, who performed forced expiratory manoeuvres with three Vitalograph spirometers at three different ambient temperatures (36.5 degrees C, 24.1 degrees C, and - 7.3 degrees C) over three days according to a Latin square design. Analysis of variance showed no significant difference between values at different ambient temperatures when measured at ATPS. Correction of the results to BTPS resulted in a significant difference in values at the three ambient temperatures for all measurements other than the Vmax25. The mean error introduced by conversion to BTPS varied from 7% (SD 5%) for the FVC at 24.1 degrees C to 30% (21%) for Vmax50 at - 7.3 degrees C. Possible explanations for these observations include the increasing compliance of the spirometer bellows with increasing temperature, relatively slow cooling of gases within the spirometer, and a combination of these effects. We conclude that there is no evidence that conversion to BTPS improves the accuracy of measurements made on a Vitalograph spirometer. Further studies on other spirometers are needed to see whether conversion to BTPS is always appropriate.

Evaluation Studies as Topic↗
PubMed1983

Value of QRS alteration in determining the site of origin of narrow QRS supraventricular tachycardia.

To determine the value of alternation of QRS morphology in determining the site of origin of sustained narrow QRS supraventricular tachycardia (SVT), we retrospectively studied 163 distinct tachycardias in 161 patients (ages 4 to 91 years) in whom the site of origin of SVT was proven by intracardiac electrophysiologic study. Sustained SVT was defined as lasting longer than 30 sec. Narrow QRS was defined as QRS width less than 0.12 sec. Atrial fibrillation and flutter were excluded. The presence or absence of QRS alternation was judged at least 10 sec after initiation of SVT. Circus movement tachycardia with anterograde AV node conduction and a retrograde accessory AV pathway was seen in 89 patients (58 with Wolff-Parkinson-White syndrome, 31 with concealed accessory pathway); intra-AV nodal reentrant tachycardia (AVNT) was present in 57 cases, and 17 tachycardias were atrial in origin. QRS alternation was present in 36 of 163 cases (22%). In only eight of these 36 did RR interval length alternation accompany alternation in QRS morphology. Thirty-three of 36 (92%) tachycardias with QRS alternation were circus movement tachycardias. Two were atrial in origin and one was AVNT. We conclude that the presence of QRS alternation during sustained narrow QRS SVT is highly indicative of a retrograde accessory AV pathway in the tachycardia circuit.

Adolescent↗
PubMed1983

Four-drug combination chemotherapy (methotrexate, cyclophosphamide, hexamethylmelamine, and CCNU) for non-small cell bronchogenic carcinoma: a Cancer and Leukemia Group B study.

Ninety-eight evaluable patients with nonresectable regional or metastatic non-small cell bronchogenic carcinoma were treated with a four-drug combination chemotherapy program of methotrexate, cyclophosphamide, hexamethylmelamine, and CCNU (MCHC). Fifteen partial or complete responses (15%) were obtained, all but one of which occurred in good performance status (0-1) patients. While "responders lived longer than non-responders", this was due more to initial performance status among responding patients than to achievement of partial (greater than 50%) or complete disease regression. Evaluation of those patients with good performance status (PS 0-1), indicated no statistically significant differences in median survival time for complete response and partial response patients compared to patients with "improved" or "stable" disease status in this group. This combination of modestly active single agents produced disappointing results in our lung cancer population. A search for more active single agents in lung cancer is necessary.

Altretamine↗
PubMed1983

Oncogenes: preliminary studies in head and neck cancer.

DNA has been extracted from squamous cell carcinomas of the larynx, base of tongue, and nasopharynx. These tumors were excised from patients at the St. Louis University Medical Center and processed at the Institute for Molecular Virology of the St. Louis University Medical Center. NIH/3T3 cells were transfected with the DNAs from these cancers. Malignant, transformed foci of NIH/3T3 cells have been observed. These foci have been cloned and grown in quantity. The cloned foci have been injected into nude mice with the production of highly malignant sarcomas. DNA extracted from these sarcomas has shown homology with human DNA on hybridization analyses of both nasopharynx and tongue cancer. Further hybridization studies are being conducted on the larynx cancer-induced sarcomas and on the DNAs taken from the original transformed foci of NIH/3T3 cells transfected with squamous cell cancers of the larynx, nasopharynx, and tongue base. Our preliminary results indicating the presence of human sequences in the mouse sarcomas support the hypothesis that human cellular transforming gene(s) may be present in the DNA isolated from the head and neck cancers. Additional studies will include repetitive retransfection of NIH/3T3 cells, molecular cloning of putative oncogenes, and DNA sequence analysis of the cloned oncogenes. It is hoped that identification of putative oncogene sequences will result in the identification of the proteins coded for by the specific nucleotide sequences responsible for malignant cellular transformation by DNA extracted from head and neck tumors.

Animals↗
PubMed1983

Repeated femoral vein cannulation for administration of chemotherapeutic agents.

A cannulation set has been designed for repeated short-term infusion of vesicant chemotherapeutic agents via the femoral vein. The major complication was thrombophlebitis in 2.1% of infusions. The procedure provides reliable venous access when therapeutic plans are changed or when the inability to provide catheter care makes an indwelling catheter unwarranted.

Antineoplastic Agents↗
PubMed1983

Coming of age in general pediatrics.

Changes that have occurred in the practice of pediatrics in the last decade are reviewed. It is suggested that in the future, general ambulatory pediatrics be conceptualized for practice and educational purposes by forming three levels of care based on the following determinants: length of time and number of visits required for the specific service provided, level of competence needed, complexity of the problem, involvement of other professionals, setting, and specific needs of the patient. Growth in Level I general ambulatory care services will come from prenatal and adolescent visits and sports medicine. Extension of general ambulatory care at Levels II and III will result from differentiation of general pediatrics into areas of special interest such as child development, behavior, neurology, allergy, developmental disabilities, and adolescence. Arrangements to facilitate the provision of care in Levels II and III by the practitioner are suggested. Pediatric biomedical and psychosocial homeostasis are discussed using a model that encompasses the child, his family, and his environment on one axis and problems, vulnerabilities, strengths, and potentialities on the other. The need to examine the content and outcome of health supervision visits is emphasized.

Ambulatory Care↗
PubMed1982

Incorporation of amino acid analogs interferes with the processing of the asparagine-linked oligosaccharide of the MOPC-46B kappa light chain.

The incorporation of the leucine analog, beta-hydroxyleucine, or the isoleucine analog, 4-thiaisoleucine, into the MPOC-46B kappa chain interfered with the processing of the oligosaccharide moiety of newly synthesized light chains. Analog-containing chains were secreted with endo-beta-N-acetylglucosaminidase H-sensitive oligosaccharides instead of the normal complex, endo-beta-N-acetylglucosaminidase H-resistant oligosaccharide. The incorporation of the analogs did not significantly decrease the overall secretion of the MPOC-46B-related proteins. These data form the basis for the hypothesis that the presence of the analog in the protein alters the peptide configuration sufficiently to prevent the processing of precursor high mannose oligosaccharides to complex oligosaccharides.

Amino Acids, Sulfur↗
PubMed1982

Improved myocardial function during exercise after successful percutaneous transluminal coronary angioplasty.

Fifty-nine consecutive patients with coronary-artery disease undergoing percutaneous transluminal coronary angioplasty were evaluated with radionuclide ventriculography at rest and during exercise before angioplasty (when possible) and afterward when it was successful. Thirty-eight patients (64 per cent) had an angiographically successful procedure. Three (5 per cent) had coronary occlusion as a complication. Arterial stenosis was reduced from 74 +/- 2 per cent to 31 +/- 3 per cent (mean +/- S.E.M.). The mean ejection fraction was 55 +/- 2 per cent at rest and 51 +/- 3 per cent during exercise before the procedure. After successful angioplasty, the ejection fraction was unchanged at rest but increased to 62 +/- 2 per cent (P less than 0.001) during exercise. Regional dysfunction was present during exercise in 94 per cent of the patients before the procedure and in only 8 per cent after successful angioplasty. Of the 38 patients in whom the procedure was successful, 19 had sustained improvement for over six months, and eight for three to six months. Eleven patients had recurrence of symptoms; the second angioplasty was initially successful in nine. In 24 patients remaining asymptomatic for six months (19 after the first procedure and five after the second), the left ventricular ejection fraction during exercise remained stable or improved.

Adult↗
PubMed1982

Temperature dependence of ultrasound-induced cell killing: the role of membrane fluidity.

Chinese hamster cells in suspension were exposed to 20 kHz ultrasound (US) at 54 W/cm2 and various temperatures between 2 and 44 degrees C. Activation energies were 2.6 and 24 kcal/mole below and above 35 degrees C, respectively. Procaine, a local anaesthetic drug known to increase membrane fluidity, enhanced cellular inactivation by US above 41 degrees C, increasing the activation energy to 62 kcal/mole. The inactivation of the bacterium Salmonella typhimurium by US was also dependent on the exposure temperature, with an activation energy of 2.9 kcal/mole between 2 and 44 degrees C. These data are most simply explained by the hypothesis that membranes are a major target for cellular inactivation by US and that the fluidity of the membranes is important in this respect.

Animals↗
PubMed1982

Fractionated low-level gamma irradiation of Chinese Hamster cells: cellular and biochemical effects.

Chinese hamster V79 cells in log-phase were exposed daily to 0.6 Gy of gamma radiation for 3-6 months. After such an exposure the population doubling time increased from 10 to 15 h. When irradiation was discontinued doubling time gradually decreased. Cell survival following acute radiation dose of the low-level irradiated cells remained the same as that of untreated cells. The fractionated irradiation did not affect the capacity of the cells to perform DNA repair synthesis. Likewise, the sensitivity to inhibition by acute radiation exposure of the ability to induce ornithine decarboxylase activity was similar in cells exposed to fractionated irradiation and in untreated cells. It is concluded that there is no apparent effect of sublethal radiation dose received in one generation on the radiation sensitivity of the succeeding generations during the log-phase of growth.

Animals↗
PubMed1982

Comparison of orally administered metaproterenol and theophylline in the control of chronic asthma.

The efficacy of metaproterenol (orciprenaline) and theophylline given orally at currently recommended doses was examined in 34 children with chronic asthma using a randomized double-blind cross-over evaluation of four weeks' duration for each active regimen. No serious adverse effects were seen with either medication, but tremor occurred more frequently with metaproterenol (P less than 0.01). No significant differences were observed in the frequency of nausea, vomiting, headache, or insomnia (P greater than 0.05). Symptoms of wheezing, coughing, exercise intolerance, and interference with sleep were more frequently associated with the oral metaproterenol regimen; completely asymptomatic days occurred 50% more frequently in association with theophylline therapy (P less than 0.01). Mean peak flows, performed twice daily during each of the four-week study periods, were 86 and 92% of predicted for metaproterenol and theophylline, respectively (P less than 0.05). Pulmonary function decreased significantly less with theophylline than with metaproterenol among those who completed six minutes of treadmill exercise during both regimens (P less than 0.05). Corticosteroids, used for acute symptoms that failed to respond to the addition of inhaled metaproterenol, were required in four patients during both regimens, in ten patients only during the metaproterenol regimen, and in one patient only during the theophylline regimen (P less than 0.02). Thus, theophylline therapy was associated with fewer adverse effects, fewer symptoms of asthma, better pulmonary function, better exercise tolerance, and less requirements for corticosteroids than was treatment with metaproterenol.

Administration, Oral↗