Search PubMed⌕ Search

Biomedical subjects

R F Wilson

Publications and source records attributed to R F Wilson.

At least 235 records · Page 13Linked to original sources
PubMed1985

Hemostasis changes during cardiopulmonary bypass surgery.

A number of hemostasis parameters were studied in a total of 63 patients undergoing cardiopulmonary bypass (CPB) for open heart surgery. In 33 patients fibrinogen, Factors II, V, VIII:C, X, XI, antithrombin, plasminogen, alpha 2-antiplasmin, and platelet counts were assayed before surgery, during maximal hypothermia, at the end of the bypass procedure, before and after protamine sulfate infusion, in the intensive care unit, and 48 hours postoperatively. All factors assayed decreased markedly when the patients were placed on the bypass machine, the drop fairly well paralleling the decrease in hematocrit. During bypass the factors remained low, although a slight tendency toward an increase was noted. Only platelet counts remained low with a decreasing trend until the end of bypass. In the intensive care unit a second decrease in fibrinogen, Factors II and V and antithrombin was noted. This drop was unrelated to four patients who experienced a greater blood loss during this time than the others. Forty-eight hours postoperatively, a marked increase could be found in all clotting factors and near normal levels were measured. Platelet counts remained low, however. The decrease in factors rarely dropped into a range where one would expect a compromised hemostasis (less than 30%). Although antithrombin levels decreased below 60%, no difficulties with heparinization were encountered. Several factors were assayed manually and by automated analyzer (Multistat III), and excellent correlations were found between both procedures. Also a good correlation was found between the activated whole blood clotting times and quantitative heparin assays. In 30 additional patients platelet function was studied before surgery, after thoracotomy, after heparin administration, after initiation of bypass, at maximal hypothermia, before and after protamine sulfate infusion, and 24 hours postoperatively. Platelet counts once again decreased as patients were placed on the CPB machine and remained low throughout the procedure. Mean platelet volumes were unchanged until protamine was given. At that time, a significant drop in mean platelet volume was recorded. Twenty-four hours postoperatively the volumes were normal again. Platelet aggregation studies were performed on a whole blood aggregometer using two concentrations of ADP, collagen, and ristocetin as aggregation inducers. A significant decrease in aggregability was seen when the patients were connected to the CPB apparatus.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1985

Interpretation of serum amylase levels in the critically ill patient.

To understand better the incidence and meaning of hyperamylasemia in the intensive care setting, cellulose acetate membrane electrophoresis was used to measure the isoenzymes of serum amylase in 192 patients with a variety of critical illnesses. Seventy of these patients had elevated serum amylase levels, but none had clinical or biochemical evidence of acute pancreatitis or renal failure. Of the 70 patients who had hyperamylasemia, in only 18 (26%) was it due solely to an elevation of the pancreatic isoamylase fraction. The remaining 52 patients were hyperamylasemic due to elevations in the nonpancreatic isoamylase fraction or elevations in both pancreatic and nonpancreatic isoamylase fractions. These data indicate that hyperamylasemia in the absence of clinical pancreatic disease is common in the ICU and is frequently caused by nonpancreatic production of serum amylase. Caution is, therefore, advised in interpreting elevated serum amylase levels in critically ill patients.

Amylases↗
PubMed1985

Cardiac tamponade due to an iatrogenic pericardial-diaphragmatic hernia.

Because of its ease, safety, and effectiveness, surgeons are increasingly using the subxiphoid approach to drain pericardial effusions and to insert epicardial pacemakers. Although we could find no previous reports of iatrogenic pericardial-diaphragmatic hernias in the literature, experience with a recent patient who developed this problem after a subxiphoid pericardial drainage suggests that it may become much more frequent. Physicians should strongly suspect this complication in patients with a triad of previous subxiphoid pericardial incision and signs of bowel obstruction and tamponade.

Aged↗
PubMed1985

Studies on Genetic Male-Sterile Soybeans : IV. Effect of Male Sterility and Source of Nitrogen Nutrition on Accumulation, Partitioning, and Transport of Nitrogen.

Soybean (Glycine max [L.] Merr.) germplasm, isogenic except for loci controlling male sterility (ms(1)) and nodulation (rj(1)), was used to investigate the effects of reproductive tissue development and source of nitrogen nutrition on accumulation, transport, and partitioning of nitrogen in a greenhouse experiment. Nodulated plants were supplied nitrogen-free nutrient solution, and nonnodulated plants were supplied nutrient solution containing 20 millimolar KNO(3). Plants were sampled from flowering until maturity (77 to 147 days after transplanting).Accumulation rates of nitrogen in whole plants during reproductive growth were not significantly different among the four plant types. Nitrogen accumulation in the sterile, nonnodulated plants, however, ceased 2 weeks earlier than in fertile, nonnodulated or fertile and sterile, nodulated plants. This early cessation in nitrogen accumulation resulted in sterile, nonnodulated plants accumulating significantly less whole plant nitrogen by 133 days after transplanting (DAT) than fertile, nonnodulated plants. Thus, changing the site of nitrogen assimilation from nodules (N(2)-fixing plants) to roots and leaves (NO(3)-fed plants) resulted in similar whole-plant nitrogen accumulation rates in fertile and sterile plants, despite the absence of seed in the latter.Leaflet and stem plus petiole tissues of both types of sterile plants had significantly higher nitrogen concentrations after 119 DAT than both types of fertile plants. Significantly higher concentrations and exudation rates of nonureide, reduced-nitrogen in xylem sap of sterile than of fertile plants after 105 DAT were observed. These latter results indicated possible cycling of nonureide, reduced-nitrogen from the downward phloem translocation stream to the upward xylem translocation stream in roots of sterile plants. Collectively, these results suggest a lack of sinks for nitrogen utilization in the shoots of sterile plants. Hence, comparison of nitrogen accumulation rates for sterile and fertile plants does not provide a definitive test of the hypothesis that reproductive tissue development limits photosynthate availability for support of N(2) fixation and nitrate assimilation in determinate soybeans.Nitrogen assimilation during reproductive growth met a larger proportion of the reproductive-tissue nitrogen requirement of nitrate-dependent plants (73%) than of N(2)-fixing plants (63%). Hence, vegetative-tissue nitrogen mobilization to reproductive tissue was a more prominent process in N(2)-fixing than in nitrate-dependent plants. N(2)-fixing plants partitioned nitrogen to reproductive tissue more efficiently than nitrate-dependent plants as the reproductive tissues of the former and latter contained 65 and 55%, respectively, of the whole-plant nitrogen at the time that nitrogen accumulation in reproductive parts had ceased (133 DAT).

Journal Article↗
PubMed1985

Transluminal, subselective measurement of coronary artery blood flow velocity and vasodilator reserve in man.

Assessment of coronary blood flow and the vasodilator reserve capacity of individual coronary arteries in the catheterization laboratory has been hampered by methodologic limitations. We have developed and validated a small Doppler catheter that can subselectively measure phasic coronary blood flow velocity (CBFV). In seven anesthetized calves, CBFV was varied from 0.1 to 5.7 times control CBFV. Changes in mean CBFV measured intraluminally by catheter in the left anterior descending and left circumflex arteries were similar to those measured simultaneously with an epicardial Doppler probe on the surface of the same vessel (n = 85, r = .95, slope = 1.04) and to changes in coronary sinus flow (n = 69, r = .97, slope = 1.06) measured with timed venous collections. Identical maximal coronary reactive hyperemic responses with the catheter present and absent in the artery being studied demonstrated that coronary obstruction by the catheter was minimal. Safety studies in six additional calves demonstrated that the catheter caused small changes in coronary endothelial permeability. Histologic studies revealed no endothelial denudation or thrombus formation. Stable phasic recordings of coronary blood flow velocity have been obtained in 58 of 70 patients studied. One of the 70 patients studied had abrupt coronary occlusion probably related to catheter-induced vasospasm. In 10 normal patients, intracoronary meglumine diatrizoate increased CBFV to 3.5 times that at rest (range 2.8 to 5.0). CBFV rose 5.0-fold after an intravenous infusion of dipyridamole (range 3.8 to 7.0). In each patient, dipyridamole produced greater vasodilation than meglumine diatrizoate. The time- and dose-response characteristics to dipyridamole infusion were heterogeneous, underscoring the advantage of continuous on-line measurement of CBFV in the measurement of vasodilator reserve. This method of measuring CBFV and assessing vasodilator reserve in the catheterization laboratory should facilitate studies of the coronary circulation in man.

Animals↗
PubMed1985

Clostridium perfringens bacteremia. Opportunist or killer?

Clostridia septicemia has traditionally been associated with severe histocytotoxic infections. Recently, due to better anaerobic culture techniques, clostridia bacteremia is seen with increasing frequency in patients without an obvious source of infection. The authors reviewed their experience with 29 patients with clostridia bacteremia. The overall mortality rate was 45 per cent. No obvious source for the clostridia bacteremia was identified in 21 patients (72%). Eighty-three per cent of the patients had polymicrobial infections. The patients were generally debilitated with significant associated systemic disease. Antibiotic therapy did not appear to have any effect on mortality. Patients with asymptomatic clostridial bacteremia are, in general, patients with advanced malignancies and chronic illnesses. Antibiotic therapy appears to have little effect on the patient's outcome.

Adult↗
PubMed1985

Antibiotic usage for methicillin-resistant Staphylococcus mycotic aneurysms.

Methicillin-resistant Staphylococcus aureus (MRSA) is increasing in incidence due to widespread use of cephalosporin antibiotics. These infections, generally, are characteristically hospital acquired and related to antibiotic pressure. The appearance of community acquired MRSA has recently been observed among IV drug abusers (IVDA). The duration and type of antibiotic therapy is controversial. Twenty patients with IVDA related mycotic aneurysms and associated soft tissue infections were evaluated. Particular attention was given to the bacteria cultured, the antibiotic therapy used and the response to therapy. Antibiotic use was inconsistent. Thirty per cent of the patients received no antibiotics. Although 62 per cent of the Staphylococcus aureus infections in this group were methicillin-resistant and quite extensive, the antibiotics used had no clinical importance. The need for vancomycin as therapy for extensive soft tissue infections with MRSA may be overrated and probably contributes to the development of increasing antibiotic resistance.

Adult↗
PubMed1985

Changes in antithrombin, antiplasmin, and plasminogen during and after cardiopulmonary bypass.

Platelet counts and several clotting parameters, especially antithrombin, alpha 2-antiplasmin, and plasminogen, were determined in 33 patients undergoing cardiopulmonary bypass surgery. Except for Factors VIII and XI, all activities measured fell significantly as the patients were placed on the pump. This initial drop paralleled the drop in hematocrit, i.e., the drop was most likely due to hemodilution. During the entire procedure the activities remained decreased, again paralleling the hematocrit. Only the drop in platelet counts was greater than the hematocrit, suggesting additional consumption during bypass. In the ICU a second significant drop in antithrombin, prothrombin, and Factor V was noted that was not reflected by a drop in hematocrit. The cause for this is not known at this time. Although the patients with the lowest antithrombin levels, compared to the highest levels in the ICU seemed to have a greater need for protamine and blood and had greater chest tube drainage, none of these changes were significantly different. Comparisons between activated clotting times (ACTs) and actual heparin levels revealed a good correlation (0.886). Good correlations were also noted when manual factor assays were compared with automated assays using an automated analyzer suggesting the potential use of automation and profiling for these patients. Possible reasons for some of the most commonly encountered postoperative bleeding problems are discussed.

Adult↗
PubMed1985

Left subcostal approach to the pericardium.

The subcostal approach, which we used in this series, gives a broader exposure to the pericardium than the straight subxiphoid exposure. It was described 40 years ago, and for some reason, is not being used widely.

Adult↗
PubMed1984

The effect of storage in liquid nitrogen on the recovery of human dental plaque bacteria.

Centrifuged deposits of various individual bacteria from type-culture collections and dental plaque samples were immersed in liquid nitrogen for periods of up to 2 years. All the organisms were recovered after storage in liquid nitrogen but Fusobacterium nucleatum (ATCC 10953) and Campylobacter fetus (NCTC 10354) consistently showed a reduction in the number of colony-forming units after freezing. The main effect on bacterial proportions in plaque samples was a reduction in aerobic Gram-negative cocci. Thus, storage in liquid nitrogen may be useful for comparative studies of dental plaque and as a means of storing individual organisms.

Adolescent↗
PubMed1984

Studies on Genetic Male-Sterile Soybeans : III. The Initiation of Monocarpic Senescence.

Soybean (Glycine max [L.] Merr.) germplasm, isogenic except for loci controlling male-sterility (ms(1)) and nodulation (rj(1)) was utilized to investigate the effects of reproductive tissue development and nitrogen source on the initiation of monocarpic senescence. The experimental genotypes (Ms(1)Rj(1), Ms(1)rj(1), ms(1)Rj(1), and ms(1)rj(1), were selected from a cross between N69-2774 and N59-5259, and were inbred to the F(5) generation. Green-house-grown plants were collected during the period of flowering (77 days after transplanting) until maturity (147 days after transplanting). Leaf tissues from the respective genotypes were analyzed at the various harvest dates for RNA, phenolic, and chlorophyll concentrations; acid protease activity; polypeptide banding patterns of chloroplast thylakoids; and chloroplastic ultrastructure.Regardless of nitrogen source, total chlorophyll concentrations declined between 77 and 119 days after transplanting, resulting in a 40% loss of chlorophyll per square centimeter in all genotypes. Leaf chlorophyll levels continued to decline at a constant rate in male-fertile genotypes, but remained at a constant level (26 micrograms chlorophyll per square centimeter) in male-sterile genotypes, for the remainder of the study. With increased leaf age, a gradual disruption of thylakoid structures was observed, particularly in chloroplasts from the male-fertile genotypes. Chloroplasts from the male-sterile genotypes appeared to lose starch grains but increased their number of chloroplastic lipid bodies with leaf aging. These data suggest that monocarpic senescence in soybeans was initiated at or before flowering. Although reproductive tissue development probably augmented the process, the response attributed to seed formation was not apparent until the mid-pod fill stage (119 days after transplanting). All genotypes had similar changes in other cellular components that are recognized as indicators of plant senescence regardless of whether the plants produced seed.

Journal Article↗
PubMed1984

Hyperamylasemia after cardiopulmonary bypass.

Postpump pancreatitis has been described to occur in patients undergoing cardiac surgery with cardiopulmonary bypass. Twenty patients were prospectively analyzed with sera drawn for total serum amylase, pancreatic isoamylase, and nonpancreatic isoamylase levels. Six of 19 patients were found to be hyperamylasemic postoperatively, the majority of which were not due to pancreatic isoamylasemia . No patient had clinical pancreatitis. These findings suggest that elevations of serum amylase is common after cardiopulmonary bypass and is not indicative of pancreatitis.

Adult↗
PubMed1984

Management of bronchopleural fistulas.

During the ten years 1972 to 1981, 16 patients with persistent bronchopleural fistulas were treated. Eleven patients had postoperative fistulas, and five had fistulas which were spontaneous in origin. The spontaneous fistulas were due to tuberculosis (three) and lung abscess (two). The postoperative bronchopleural fistulas occurred after pulmonary resections for cancer (six), aspergillosis (three) and bronchiectasis (two). All of the postoperative fistulas developed in patients in whom the nonresected lung failed to fill the pleural cavity. The pneumothorax space then became infected, and breakdown of the sutured bronchus followed. Two patients died before any surgical intervention could be carried out. Two patients had successful resuture of a leaking bronchial stump two and eight days after their initial operation. Two healed after prolonged chest tube drainage. In ten patients, a thoracoplasty was required before closure of the fistula was accomplished. One of these patients died eight weeks postoperatively of sepsis involving the other lung.

Adult↗
PubMed1984

Iatrogenic hiatal and diaphragmatic hernias.

Seven patients with hernias occurring after Belsey hiatal hernia repair are described. These hernias were of two types. Four occurred through the hiatus, had the appearance of a parahiatal hernia, and were attributed to the failure to correct a shortened esophagus. In three patients the hernia occurred through a disrupted counterincision in the diaphragm. In the second group postoperative abdominal distension and possibly technical faults were incriminated. In the first group satisfactory repair was achieved by a Collis-Belsey gastroplasty and an antireflux procedure. In the second group reduction of the hernia and resuture of the diaphragm incision encompassing all layers corrected these life threatening hernias.

Female↗