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Biomedical subjects

M J Smith

Publications and source records attributed to M J Smith.

At least 325 records · Page 18Linked to original sources
PubMed1984

Actin genes from the sea star Pisaster ochraceus.

Genomic and tube foot cDNA recombinant libraries have been prepared from the sea star Pisaster ochraceus. Three major classes of actin-bearing lambda phage clones have been identified on the basis of restriction enzyme mapping and localization of actin coding regions. There are at most six non-allelic actin genes in the sea star genome. Southern blots of restriction enzyme-digested genomic DNA from individual sea stars probed with actin coding sequences indicate extensive polymorphism in actin gene regions. The locations of repetitive sequences within the genomic clones have been mapped. Approx. 1% of cDNA clones prepared from tube foot poly(A) RNA contain actin coding segments. The actin gene(s) from which the tube foot actin transcripts originate have been identified by hybridization with a 460 bp 3' untranslated region from one of the cDNA plasmids. Hybridization of the untranslated region probe with genomic digests demonstrates that there are at least three alleles for the tube foot actin in sea star populations.

Actins↗
PubMed1984

Extracorporeal circulation for renal cell carcinoma with supradiaphragmatic vena caval thrombi.

Extension of tumor into the vena cava occurs in 5 to 10 per cent of the cases of renal cell carcinomas. Of these cases 14 to 39 per cent may extend to or into the right atrium. Acceptable techniques for dealing with this situation include cross-clamping the atrium, using positive pressure ventilation and extracting the thrombus with a Fogarty or Foley catheter, and extracorporeal circulation or a cardiopulmonary bypass with open excision of the tumor extension. Since 1974 we have seen 2 men and 2 women, mean age 56 years, with clear cell renal carcinomas and supradiaphragmatic vena caval tumor extension (1 with additional pulmonary embolism). None had other evidence of metastatic disease determined on staging evaluation by celiac and renal angiography, liver scan, bone scan and chest tomography. Each patient was explored with the planned use of extracorporeal circulation or cardiopulmonary bypass, Greenfield vena caval filter insertion and standard radical nephrectomy. Resection was not done in 1 patient with biopsy proved tumor eroding through the right atrial wall. He died of disease in 8 months. Of the remaining 3 patients who had the tumors completely resected 1 is alive with recurrent disease in the retroperitoneum at 44 months, 1 died of metastatic disease to the bones and liver at 39 months, and 1 died 1 day postoperatively of technical complications with no evidence of residual disease at autopsy. In the absence of metastatic disease it seems reasonable to pursue a radical surgical approach in patients with renal cell carcinoma and supradiaphragmatic tumor thrombus. The use of extracorporeal circulation and post-extraction insertion of the Greenfield vena caval filter offers the surgeon the advantage of direct visualization and better vascular control in removing the thrombus, as well as protection from the possibility of post-extraction pulmonary embolism. With the combined use of these techniques, the previously hopeless situation for these patients has been improved.

Adenocarcinoma↗
PubMed1984

A graduate program designed for medical and other doctoral degree applicants.

The data collected during the evaluation of the natural science program at Roswell Park revealed a high rate of success in preparing students to enter health and science related careers. An average of 50 percent of the entering students each year had been unsuccessful medical school applicants or students preparing to enter Ph.D. programs following an initial research experience. The program assists students in admission to medical and research programs and encourages research participation. Many graduate programs will not accept or find difficulty dealing with students who have career goals in medicine and are not necessarily in research. This is understandable, especially in Ph.D. granting programs with substantial investments of faculty time and funding. The philosophy of the program reported here is to assist the students to enter the career of their choice; however, at the same time, the faculty members insist on a high level of scholarship in course work and research during the program. With this philosophy, the program continues to be successful in attracting students of high quality.

Education, Graduate↗
PubMed1984

Mycobacterial isolations in young adults with cystic fibrosis.

In 223 patients admitted to hospital with cystic fibrosis mycobacteria were found in the sputa of seven. All of these cases were identified over a six year period after the introduction of routine examination and culture of sputum for acid fast bacilli in patients with cystic fibrosis. The organisms isolated were Mycobacterium tuberculosis in three patients, M chelonei in one, M fortuitum in one, and unidentified mycobacteria in two. The diagnosis was not suspected on clinical grounds in any of the cases; in one patient, however, night sweats were a prominent feature before diagnosis. In four of the patients direct sputum smear examination did not reveal the organism, which was grown subsequently in culture. An unusual phenomenon of liquefaction of the Lowenstein-Jensen culture medium was encountered in five of the seven patients described, which in one case made identification and sensitivity testing of the organism impossible. This phenomenon has been observed in sputum cultures from other patients with cystic fibrosis but not in other pulmonary diseases. Immunological studies performed in three of the patients showed normal numbers of peripheral blood T and B lymphocyte in all three; in vitro lymphocyte transformation to tuberculin PPD was, however, reduced in the patient with extensive M fortuitum infection, which proved fatal. Mycobacteria may be present in the sputa of patients with cystic fibrosis more often than previously recognised and therefore sputum examination and culture for mycobacteria should be performed periodically in these patients.

Adolescent↗
PubMed1984

Multiplicative interaction between angiotensin II and K concentration in stimulation of aldosterone.

The interaction of angiotensin II and plasma K concentration in stimulating aldosterone secretion was studied in a group of six dogs by determining the aldosterone response to three levels of angiotensin II while the dogs were maintained on three levels of K intake. The levels of angiotensin were 1) the endogenous level, 2) the concentration resulting from infusion of 5 ng X kg-1 X min-1, and 3) the concentration resulting from infusion of 10 ng X kg-1 X min-1. Each level was maintained for 5 days. The three rates of K intake were 10, 100, and 200 meq/day, each maintained for 3 wk. Data were analyzed from days 1, 2, and 5 of the angiotensin infusion periods. The regressions obtained from plotting plasma K (PK) versus aldosterone concentration on day 5 of each level of infusion were 1) for no infusion (endogenous PRA = 0.4 to 0.5 ng ANG I X ml-1 X h-1), aldosterone = 5.04 X PK - 16.56; 2) for 5 ng X kg-1 X min-1 infusion, aldosterone = 12.20 X PK - 39.09; and 3) for 10 ng X kg-1 X min-1 infusion, aldosterone = 35.50 X Pk - 119.31. Each regression was significantly different (P less than 0.001) from the other two. The plasma K axis intercepts, which are the points at which aldosterone secretion is zero, were 3.29, 3.20, and 3.36 for the regression from the 0, 5, and 10 ng X kg-1 X min-1 infusion rates, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1984

Mechanisms of escape from sodium retention during angiotensin II hypertension.

This study examined the role of increased renal arterial pressure (RAP) in renal escape from the chronic Na-retaining effects of angiotensin II (ANG II). When RAP was allowed to increase during ANG II infusion (5 ng X kg-1 X min-1), urinary Na excretion (UNaV) decreased transiently on the first day but there was no significant change in Na iothalamate space or cumulative Na balance when ANG II infusion was continued for 6 days. Mean arterial pressure (MAP) rose from 100 +/- 3 to 132 +/- 2 mmHg after 3 days and remained near that level for the next 5 days of ANG II infusion. When RAP was prevented from rising with a servo-controlled aortic occluder, UNaV remained below control even after 6 days of ANG II infusion, cumulative Na balance increased by 210 +/- 37 meq, and Na iothalamate space rose by 1,158 +/- 244 ml. MAP did not plateau when RAP was servo-controlled during ANG II infusion but continued to rise and after 6 days averaged 157 +/- 3 mmHg. In three of the eight dogs in which RAP was servo-controlled during ANG II infusion, Na and water retention became so severe that MAP increased to 165-180 mmHg and pulmonary edema developed within 4-6 days. These data suggest that a rise in RAP is essential in allowing the kidneys to escape from the chronic Na-retaining actions of ANG II and in attaining Na balance and a stable level of MAP without severe volume expansion.

Aldosterone↗
PubMed1984

Serum theophylline by fluorescence polarisation immunoassay.

The Abbott TDX system utilises the principles of fluorescence polarisation and competitive binding analysis for the quantitation of drug levels in plasma. The system proved easy to use, and produced reliable results rapidly. The high cost of reagents is balanced by the fact that the reagents are stable and therefore the assays can be calibrated infrequently.

Humans↗
PubMed1984

Rapid loss of lactate dehydrogenase isoenzyme activity in serum by cold-induced formation of immunoglobulin G-lactate dehydrogenase complex.

Lactate dehydrogenase (LD; EC 1.1.1.27) activity in serum from a patient recovering from a myocardial infarction was extremely unstable when stored at 0 degree C. The activity of each LD isoenzyme except LD-1 decreased by at least 40% when serum was stored at 0 degree C for 4 h. The patient's erythrocyte LD activity had normal stability at lower temperatures, but LD from other sources, when added to the patient's serum, rapidly lost activity at 0 degree C. The patient's serum contained an immunoglobulin G that combined--at 0 degree C but not at 21 degrees C--primarily with LD isoenzymes containing one or more M subunits. Because this immunoglobulin-LD complex has no enzyme activity, we used 125I-labeled purified LD to study formation of the complex. NAD+ blocked the formation of immunoglobulin-LD complex but could not dissociate the complex and restore the LD activity.

Animals↗
PubMed1984

Cytopathologic features of medullary carcinoma of the thyroid.

Medullary carcinoma of the thyroid (MCT) presents a varied but characteristic cytologic pattern in cellular samples obtained by fine-needle aspiration (FNA) biopsy. In our experience with 17 cases of MCT, ten were identified by cytologic examination. One was acellular. The remaining six were typed as undifferentiated carcinoma (three cases), follicular variant of papillary carcinoma (one case), and cellular adenoma (two cases). Four Hürthle cell tumors and four papillary carcinomas were incorrectly typed as MCT. There was one false positive. Careful consideration of the listed cytologic features should make the FNA biopsy diagnosis of MCT of satisfactory sensitivity for the evaluation of "cold" thyroid nodules. Specificity may be considerably improved by using immunoperoxidase stain for calcitonin granules and/or by large-needle biopsy.

Adenocarcinoma↗
PubMed1983

High-dose beclomethasone inhaler in the treatment of asthma.

The effects of long-term use of high-dose inhaled beclomethasone dipropionate (BDP) were studied retrospectively in 293 asthmatic patients who were not adequately controlled on conventional doses of BDP or who required oral corticosteroids to control their asthma. The higher doses of BDP were administered in a high-dose beclomethasone aerosol (BDP 250) containing 250 micrograms BDP per metered dose. 27% of the steroid-dependent asthmatics were able to stop oral steroids altogether after the introduction of BDP 250, and a further 39% were able to reduce their daily dosage. Improvement in asthma control was achieved in 62% of all patients and was accompanied by a reduction in the number of severe acute exacerbations and a significant increase in mean peak expiratory flow rate. Oropharyngeal candidiasis was not significantly more common with the BDP 250 inhaler than with conventional inhalers and appears to have been related to the number and frequency of inhalations and not solely to the total dosage. Other side-effects were very rare.

Aerosols↗
PubMed1983

Suppressed visual adaptation of the vestibuloocular reflex in catecholamine-depleted cats.

Intracisternal injections of 6-hydroxydopamine were used to deplete brain catecholamines in cats. These animals were then subjected to a prolonged period of lateral head rotations while viewing a visual scene that always rotated with them. In contrast to their predepletion behavior, these cats showed very little decrease in the gain of their vestibuloocular reflex. These results suggest that brain catecholamines may play a role in regulating neural plasticity in the vestibuloocular system just as they appear to do in the visual cortex.

Animals↗
PubMed1983

Deep vein thrombosis and prostatectomy.

A research protocol to evaluate the prevention of deep vein thrombosis in sequential patients undergoing prostatectomy is presented. There is an overall incidence of deep vein thrombosis in 8 per cent of patients. There was no advantage with intermittent leg compression when compared with elastic stockings.

Clothing↗
PubMed1983

Concanavalin A acceptor glycoproteins: a new type of marker for the classification of tumour cells.

The Con A acceptor glycoproteins of murine and human tumour cell lines revealed by two-dimensional fingerprinting on polyacrylamide gels fall into two main categories: constant glycoproteins expressed by all cell lines and variable glycoproteins which are only expressed by particular tumour cell lines. Since the number of variable glycoproteins on a typical fingerprint is 50, fingerprints from different cell lines are readily distinguishable. However the variable glycoproteins are not expressed idiosyncratically and cell lines derived from similar classes of tumours express similar patterns of the variable glycoproteins. For example, murine fibrosarcomas express patterns which are virtually identical with one another. Characteristic patterns are also expressed by murine macrophage tumour lines, human carcinomas and human B lymphoblastoid cells. Thus, the variable glycoproteins behave as a set of linked markers which are indicators of the type of normal pre-neoplastic precursor cell from which a tumour is derived and appear to be a new type of marker for tumour cell classification. Antibodies to these glycoproteins could prove useful in tumour localisation and diagnosis.

Animals↗