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Biomedical subjects

R F Wilson

Publications and source records attributed to R F Wilson.

At least 253 records · Page 14Linked to original sources
PubMed1983

Cerebral cortical perfusion during and following resuscitation from cardiac arrest in dogs.

Perfusion of the cerebral cortex during closed chest CPR in dogs, generating systolic pressures of 60 to 70 mmHg, is only 10% of pre-arrest blood flow. In contrast, internal cardiac massage produces normal cortical perfusion rates. Following a 20-min perfusion arrest, during pressure controlled reperfusion, cortical flow rates decay to less than 20% normal after 90 min of reperfusion. This appears to be due to increasing cerebral vascular resistance, and is not due to rising intracranial pressure. The post-arrest cortical hypoperfusion syndrome is prolonged with cortical flow remaining below 20% normal up to 18 hr post arrest. The use of a variety of calcium antagonists, including flunarizine, lidoflazine, verapamil, and Mg2+, immediately post-resuscitation maintains cerebral vascular resistance and cortical perfusion at normal levels. A prospective blind trial of the calcium antagonist lidoflazine following a 15-min cardiac arrest in dogs and resuscitation by internal massage, demonstrates amelioration of neurologic deficit in the early postresuscitation period.

Adenosine Triphosphate↗
PubMed1983

Calcium blockers in cerebral resuscitation.

Recent studies on cerebral resuscitation following an ischemic anoxic insult suggest that both inadequate reperfusion and direct neuronal death are partially initiated by calcium entry into vascular smooth muscle and neurons. To investigate the effects of calcium blocking agents on cerebral resuscitation, a controlled perfusion arrest model with cardiopulmonary bypass was used. Post-resuscitation regional cerebral cortical blood flow (rCCBF) and intracranial pressures (ICP) were monitored in five control dogs and in 12 study dogs resuscitated after a prolonged (20-minute) cardiac arrest. The resuscitation included dexamethasone and three agents thought to be calcium entry antagonists and to offer potential cerebral protection after complete prolonged cerebral ischemic anoxia. Prearrest rCCBF measured by a thermal dilution method with a thermistor placed on the cerebral cortex was 2.0 +/- 0.6 (S.D.) ml/gm/min on bypass at 100 mm Hg mean arterial pressure. Twenty minutes after resuscitation was begun, the rCCBF in ml/min/gm were: controls 1.1 +/- 0.3; dexamethasone (2 mg/kg) 1.2 +/- 0.4; MgSO4 (100 mg/kg) 1.8 +/- 0.5; verapamil (0.15 mg/kg) 1.9 +/- 0.4; and lidoflazine (1 mg/kg) 1.5 +/- 0.3. Ninety minutes following the beginning of resuscitation the rCCBF were: controls 0.1 +/- 0.1; dexamethasone 0.1 +/- 0.1; MgSO4, 1.7 +/- 0.3; verapamil, 1.9 +/- 0.4; and lidoflazine, 1.5 +/- 0.3 ml/gm/min. Thus the Ca2+ entry antagonists maintained cerebral blood flow at 20 and 90 minutes following a prolonged ischemic anoxic insult. Dexamethasone was no better than control. These data suggest that calcium entry blockers can maintain rCCBF and may have a significant role in cerebral resuscitation following cardiac arrest.

Animals↗
PubMed1983

Studies on Genetic Male-Sterile Soybeans : II. Effect of Nodulation on Photosynthesis and Carbon Partitioning in Leaves.

Soybean (Glycine max L. Merr.) germplasm, essentially isogenic except for loci controlling male sterility (ms(1)) and nodulation (rj(1)), were developed to study the effects of reproductive development and nitrogen source on certain aspects of photosynthesis. Plants were sampled from flowering (77 days after transplanting) until maturity (150 days after transplanting). With all four genotypes, net carbon exchange rates were highest at flowering and declined thereafter. Photosynthetic rates of the sterile genotypes (nodulated and non-nodulated) declined more rapidly than the fertile genotypes, and after 105 days, both sterile genotypes maintained low but relatively constant carbon exchange rates (<3 milligrams CO(2)/gram fresh weight per hour). Photosynthetic rates and starch accumulation (difference between afternoon and morning levels) declined with time. The sterile genotypes attained the highest morning starch levels, which reflected reduced starch mobilization. After 92 days, the proportion of photosynthetically fixed carbon that was partitioning into starch (relative leaf starch accumulation) in the sterile genotypes increased dramatically. In contrast, relative leaf starch accumulation in the fertile genotypes remained relatively constant with time. Throughout the test period, all four genotypes maintained leaf sucrose levels between 5 and 15 micromoles glucose equivalents per gram fresh weight.The activities of sucrose phosphate synthase (SPS) in leaf extracts of the four genotypes declined from 77 to 147 days. Nodulated genotypes tended to maintain higher activities (leaf fresh weight basis) than did the non-nodulated genotypes. In general, relative leaf starch accumulation was correlated negatively with the activity of SPS (normalized with leaf net carbon exchange rate) in leaf extracts for all four genotypes during early reproductive development, and for the fertile genotypes at all sampling dates. In contrast, leaf sucrose content was correlated positively with SPS activity during early reproductive development. These results suggested that a direct relation existed between the activity of SPS and starch/sucrose levels in soybean leaves. However, the interaction between these processes also may be influenced by other factors, particularly when leaf photosynthetic rates and plant demand for assimilates is low, as in the sterile genotypes.

Journal Article↗
PubMed1983

Management of malignant bronchoesophageal fistulas.

Twenty-four patients with a bronchoesophageal fistula due to a malignant lesion were seen during the eight years from 1974 to 1981. Twenty of the patients had carcinoma of the esophagus, and four patients had carcinoma of the lung. All three patients who had a Celestin tube inserted had gastric reflux, and in two, the fistula was not completely occluded. Four patients who had a cervical esophagostomy, feeding jejunostomy and ligation of the gastroesophageal junction died in the immediate postoperative period. The best palliative result was achieved in 17 patients who had a bypass of the fistula with the stomach. Fourteen had a substernal gastric bypass to the cervical portion of the esophagus, and three patients had a gastric bypass to the upper thoracic portion of the esophagus by way of a right thoracotomy. Although the operative deaths occurred in six of 17 patients, the surviving patients resumed oral feeding within ten to 14 days after operation, and the pneumonias cleared. These patients had, by far, the best palliative result. We, therefore, advocate substernal or intrathoracic bypass of the bronchoesophageal fistula as soon as the general condition of the patient permits.

Adult↗
PubMed1982

Characterization of Chloroplasts Isolated from Triazine-Susceptible and Triazine-Resistant Biotypes of Brassica campestris L.

Chloroplasts isolated from triazine-susceptible and triazine-resistant biotypes of Brassica campestris L. were analyzed for lipid composition, ultrastructure, and relative quantum requirements of photosynthesis. In general, phospholipids, but not glycolipids in chloroplasts from the triazine-resistant biotype had a higher linolenic acid concentration and lower levels of oleic and linoleic fatty acids, than chloroplasts from triazine-susceptible plants. Chloroplasts from the triazine-resistant biotype had a 1.6-fold higher concentration of t-Delta3-hexadecenoic acid with a concomitantly lower palmitic acid concentration in phosphatidylglycerol. Phosphatidylglycerol previously has been hypothesized to be a boundary lipid for photosystem II. Chloroplasts from the triazine-resistant biotype had a lower chlorophyll a/b ratio and exhibited increased grana stacking. Light-saturation curves revealed that the relative quantum requirement for whole chain electron transport at limiting light intensities was lower for the susceptible biotype than for the triazine-resistant biotype. Although the level of the chlorophyll a/b light-harvesting complex associated with photosystem II was greater in resistant biotypes, the increased levels of the light-harvesting complex did not increase the photosynthetic efficiency enough to overcome the rate limitation that is inherited concomitantly with the modification of the Striazine binding site.

Journal Article↗
PubMed1982

Fatty Acid Composition and Nitrate Uptake of Soybean Roots during Acclimation to Low Temperature.

Fatty acid composition of old and new roots was determined for soybeans (Glycine max [L.] Merr. cv Ransom) at root-zone temperatures of 14, 18, and 22 degrees C during a 26-day period. New roots had a greater concentration of polyunsaturated fatty acids than old roots. The ratio of polyunsaturated to saturated fatty acid concentration in new roots exposed to 14 and 18 degrees C peaked at 16 days and declined, while the corresponding ratio in old roots increased throughout the treatment period. Apparently the response of fatty acid composition in old and new roots to low temperature was mediated by tissue aging or differentiation. These findings were contrary to the concept that modifications in fatty acid composition remain constant at lower temperatures.The function of root tissues exposed to lower temperature was evaluated with respect to the ability of the root systems to absorb NO(3) (-). Over the relatively long periods of exposure, the ability of whole root systems to absorb NO(3) (-) was similar at cool and warm temperatures. The effect of cool temperature on functioning of roots appeared to involve reductions in the rates of initiation and differentiation of young root tissues rather than changes in membrane permeability related to alteration of fatty acid composition.

Journal Article↗
PubMed1981

Complete eradication of squamous cell carcinoma of the esophagus with combined chemotherapy and radiotherapy.

Chemotherapy (with 5-fluorouracil and either mitomycin-C or cis-platinum) combined with radiotherapy was used either for palliation or as preoperative therapy in 67 patients with squamous cell carcinoma of the esophagus. In 25 patients having chemotherapy and 5000-6000 rads, good local palliation was obtained in 11 (49%) without surgery. In the remaining 25 patients, swallowing was restored with a variety of procedures (primarily Celestine tube or gastric bypass). The average survival time was seven months and two patients are still alive at 9 and 12.5 months. Of 42 patients receiving preoperative chemotherapy and radiotherapy, 35 had surgery. Of these, 13 (37%) had complete eradication of their tumors with no histologic evidence of carcinoma in the resected esophagus or associated lymph nodes. In another six (17%), the only evidence of tumor was small microscopic foci of cancer cells in the wall of the esophagus. The 6-, 12-, and 24-month survival rates for patients having surgery after the combined preoperative chemotherapy and radiotherapy were 83 per cent, 52 per cent, and 30 per cent, respectively. These results are far superior to those previously obtained.

Adult↗
PubMed1981

The use of anterior mediastinotomy to assess intrathoracic lesions.

A ten-year experience (1970-1979) with 164 anterior mediastinotomies at a VA hospital to diagnose pulmonary or mediastinal lesions or to assess the resectability of carcinoma of the lung is reported. of 135 attempts to obtain diagnosis, 130 (96%) were successful. Of 19 patients who had a subsequent thoracotomy because the anterior mediastinotomy suggested that a curative resection was possible, 17 (90%) had successful resections. Two (1.7%) patients died-one of a paraneoplastic syndrome and one from progressive respiratory failure. Eleven complications in the 162 survivors included eight minor wound infections, an initially unrecognized pneumothorax, persistent bleeding from a lymph node biopsy site, and an air leak necessitating reoperation in another. Anterior mediastinotomy is a relatively safe procedure, even in patients with advanced carcinoma or lung disease. it has much less risks than a formal thoracotomy and provides much better exposure and diagnostic possibilities than a mediastinoscopy.

Adenocarcinoma↗
PubMed1981

Etiology, diagnosis, and prognosis of positive blood cultures.

The case records of 516 patients with 613 organisms from positive blood cultures at Detroit General Hospital (1975) and Harper-Grace Hospitals (first half of 1979) were analyzed. Gram-negative bacilli predominated by 46 per cent at Detroit General Hospital and 39 per cent at Harper-Grace Hospital. The gram-negative bacteremias also had higher mortality rates (47 per cent at Detroit General Hospital and 39 per cent at Harper-Grace Hospital) than the other organisms (27 per cent at Detroit Hospital and 25 per cent at Harper-Grace Hospital). The lung was the most frequent source for positive blood cultures at Detroit General Hospital (42%), whereas the urinary tract was the major primary site at Harper-Grace Hospital (30%). If sepsis was not diagnosed and operated upon aggressively prior to the development of shock or organ failure, the mortality rate rose from 12 per cent to 64-88 per cent. Increased efforts must be made to diagnose sepsis early and drain any collections of pus, particularly in anergic patients who may show little or no evidence of sepsis even after the development of multiple organ failure or shock.

Colonic Diseases↗
PubMed1981

Comparison of the results of esophagectomy with and without a thoracotomy.

Two techniques of esophagectomy for carcinoma of the esophagus were compared in 41 patients. Of these, 39 had chemotherapy or radiotherapy, or both, preoperatively. Overall, the 20 patients who had a blind esophagectomy through an abdominal and a cervical incision without a thoracotomy tolerated the procedure quite well. However, two patients died three and five weeks afterward of arrhythmia and respiratory insufficiency, respectively. None of the 21 patients having an esophagectomy by means of a standard thoracotomy died. The blind esophagectomy took an hour less to perform and required slightly more blood than the standard thoracic esophagectomy. Except for the one patient who died of respiratory insufficiency, it appeared that the patients not having a thoracotomy had less pulmonary complications and required less ventilator assistance. The length of stay was almost identical. The main advantages found were the ease of the operation, no change needed in the position of the patient and the shorter duration of the operation. Theoretic advantages, not yet confirmed, include decreased mortality and morbidity if an anastomotic leak occurs and decreased change of local recurrence of the carcinoma.

Adenocarcinoma↗
PubMed1981

Eradication and palliation of squamous cell carcinoma of the esophagus with chemotherapy, radiotherapy, and surgical therapy.

Between April, 1977, and March, 1981, 86 unselected patients with proved squamous cell carcinoma of the esophagus were treated with a combination of chemotherapy and radiotherapy followed by operation whenever feasible. The preoperative chemotherapeutic agents used initially were 5-fluorouracil, and mitomycin C. After December, 1979, cis-platinum was used instead of mitomycin C. Radiotherapy (3,000 rads) of the tumor was begun at the same time as the chemotherapy. An esophagectomy was performed on suitable candidates 3 to 4 weeks after the chemotherapy and radiotherapy were completed. The mucosal lesion disappeared in 69 of the 86 patients, and dysphagia was relieved at least temporarily in 57 of 62 patients. Recurrent dysphagia resulting from fibrosis at the tumor site caused a secondary stenosis in 11 patients. Excellent palliation was obtained in five patients with bronchoesophageal fistulas who had an initial substernal gastric bypass followed by chemotherapy and radiotherapy. Of the 48 patients who had an esophagectomy, 15 (31%) had no tumor in the resected specimen. Eleven of these 15 patients are still alive with no evidence of disease. All patients with a lesion less than 5.0 cm in length had complete regression of the tumor. We believe that this combination of chemotherapy, radiotherapy, and surgical therapy provides excellent palliation, increases resectability, and has a potential for cure.

Adult↗
PubMed1980

The pathophysiology of shock.

This is a very brief, superficial and biased discussion of the pathophysiologic changes in shock. It was designed to provide some insight into the very complex changes that occur, with particular attention to a few examples of the impaired cell metabolism, including changes in ATP, cAMP, and calcium. Although inadequate tissue perfusion through nutrietn capillaries is the main etiologic factor in most types of shock, it is not the primary problem in many patients, particularly those with early or hyperdynamic sepsis. The importantance of oxygen consumption and the possible benefits of higher hemoglobin levels are discussed to some extent because of their possible clinical application.

Acid-Base Imbalance↗
PubMed1980

Mitochondrial O2 use and ATP synthesis: kinetic effects of Ca++ and HPO4(-2) modulated by glucocorticoids.

We have studied the effect of increased Ca++ on rat liver mitochondrial O2 consumption and modulation of the effects of the Ca++ by varying levels of HPO4(-2). Moreover, we have studied the acute in vitro effects of glucocorticoids on this system. Our data indicate that: 1) 200 microM Ca++ produces uncoupled respiration by mitochondria and blocks ATP synthesis: 2) HPO4(-2) increases the velocity and duration of uncoupled O2 consumption induced by Ca++. The HPO4(-2) effect fits Michaelis-Menton kinetics, indicating a specific site for the action of HPO4(-2) with a Km (1/2 saturation constant) of 5 mM; 3) dexamethasone acts acutely (without prefeeding) as an allosteric inhibitor of the HPO4(-2) system; and 5) uptake kinetics done with tritium-labeled dexamethasone into fresh intact human leukocytes demonstrate equilibration into the cell within 60 sec with a very large Vmax of transport at the plasma membrane. Critically ill patients with reduced tissue perfusion have lowered ionized calcium blood levels. This reflects movement of this ion into the cytosol as the plasma membrane Ca++ pump begins to fail. Clinical implications of our study are that: 1) administration of therapeutic Ca++ in hypoperfused patients with low serum Ca++ levels may be contraindicated because this will only increase the Ca++ load on the mitochondria and further depress ATP synthesis; 2) glucocorticoids administered to these patients offer partial protection of the mitochondria from uncoupling and improve ATP synthesis; and 3) effective doses of glucocorticoids are probably near optimum at four to five times the K.

Adenosine Triphosphate↗
PubMed1980

The validity of two-hour creatinine clearance studies in critically ill patients.

To determine the accuracy of 2-h creatinine clearance studies in critically ill surgical patients, 12 consecutive 2-h specimens of urine were collected on 30 patients in a surgical ICU. The 2-, 4-, 6-, 8-, 12-, and 24-h creatinine clearances that were calculated averaged 66 +/- 58 (SD), 59 +/- 45, 62 +/- 49, 63 +/- 48, 66 +/- 50, and 59 +/- 38 ml/min. The correlation coefficient between the 2- and 24-h creatinine clearance was 0.85 (p less than 0.001). The main factor causing differences between the 2- and 24-h creatinine clearance values was variability in urine output. When the average hourly urine output was essentially the same for the 2- and 24-h urine specimens, the correlation coefficient was 0.94. A relatively easy 2-h urine collection can provide essentially the same indication of creatinine clearance as a 24-h sample, particularly if urine output remains constant.

Creatinine↗
PubMed1980

Involvement of phospholipids in polyunsaturated Fatty Acid synthesis in developing soybean cotyledons.

Developing soybean (cv. Dare) cotyledons harvested at 30 days after flowering were pulse-labeled with [1-(14)C]oleoyl-CoA. The metabolic interrelation of radiolabeled unsaturated fatty acids between the major glycerolipid classes was determined at various time intervals. At chase time zero, [(14)C]oleic acid accounted for 99.2% of the total glycerolipid radioactivity, and phospholipids contained 92% of the total incorporated radioactivity. With time, phospholipids were metabolized in triacylglycerol biosynthesis and radioactivity was detected in polyunsaturated fatty acids. The hypothesis that phospholipids were metabolic intermediates in polyunsaturated fatty acid biosynthesis was tested by comparing the theoretical and the actual amount of radiolabeled oleic acid that was associated with triacylglycerol as a function of time. The radioactive oleic acid found in triacylglycerol at various intervals was derived from phospholipids via a diacylglycerol intermediate. Assuming no phospholipid desaturation, the potential or theoretical amounts of [(14)C]oleic acid that could be transferred to triacylglycerol from phospholipids was defined by a system of differential equations. The results demonstrated that the decline in [(14)C]oleic acid from phospholipid after long chase intervals was equal to the total amount of radioactive unsaturated fatty acids found in neutral lipids. The difference between the theoretical and actual amounts of [(14)C]oleic acid present in triacylglycerol after long time intervals was equal to the amount of radioactivity present in polyunsaturated fatty acids. Based upon those findings in soybeans, the desaturation of oleic acid associated with phospholipids was highly probable.

Journal Article↗