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Biomedical subjects

C J Ryan

Publications and source records attributed to C J Ryan.

At least 55 records · Page 3Linked to original sources
PubMed1990

Intraoperative autotransfusion in vascular surgery.

To determine the impact of intraoperative autotransfusion on vascular surgical care, data related to 304 major vascular surgical operations performed over a 42-month period were retrospectively analyzed. Procedures included abdominal aortic aneurysmectomy (N = 152), aortobilateral femoral bypass (N = 60), thoracoabdominal aortic aneurysmectomy (N = 20), and other vascular procedures (N = 68). Fifty percent of the transfusion requirement was met by autotransfusion for the average patient. The per patient average volumes (liters) autotransfused were as follows: elective abdominal aortic aneurysmectomy, 0.87 L and nonelective, 1.45 L; elective aortobilateral femoral bypass, 0.63 L; elective thoracoabdominal aortic aneurysmectomy, 2.47 L, and nonelective, 2.15 L; and elective other, 0.53 L and nonelective, 1.30 L. Results of immediate postoperative and hospital discharge hemoglobin, hematocrit, and coagulation studies (prothrombin time, partial thromboplastin time, and platelets) did not differ from results of preoperative studies in any group. Neither mortality nor morbidity was related to intraoperative autotransfusion. These data suggest that intraoperative autotransfusion is a safe blood replacement method during major vascular surgical operations.

Adult↗
PubMed1990

Dietary patterns, gastrointestinal complaints, and nutrition knowledge of recreational triathletes.

Dietary habits, nutrition knowledge, and gastrointestinal complaints were evaluated in 21 female and 50 male triathletes; 30 completed hemoccult slides to determine the frequency of gastrointestinal bleeding. Triathletes trained 11 h/wk with weekly distances of 5.3, 116.5, and 40.9 km for swimming, biking, and running, respectively. Mean daily energy intake averaged 9058 and 11,591 kJ for women and men, respectively; 53.8% of the energy was from carbohydrates. Mean intakes of vitamins and most minerals exceeded the Recommended Dietary Allowances (RDAs), but many had intakes below RDAs for some nutrients; greater than 60% had low zinc and copper intakes. Because 39% took a daily multivitamin-mineral supplement, some had intakes 200-600% above the RDA. Although there were notable misconceptions about nutrition, nutrition knowledge was high. Upper-gastrointestinal complaints, reported by 50%, included bloating and abdominal gas; the incidence of positive hemoccult slides was 27%. The relation among performance, dietary patterns, nutrition knowledge, and gastrointestinal function remains to be established.

Adult↗
PubMed1990

Transference of hepatic coma to normal rats from galactosamine treated donors by reverse plasma exchange.

It was possible by exchange transfusion to induce the same grade of hepatic coma in normal recipients as had occurred in donors which had previously been treated with D(+) galactosamine hydrochloride (HCl). The exchange transfusion was carried out by carotid arterial and jugular venous cannulation in conscious and unrestrained recipient rats. Thus, the coma inducing compounds generated as a consequence of acute hepatic failure, appear to circulate in the plasma for a considerable time after galactosamine-HCl is cleared and these substances are able to affect the nervous system in the presence of an intact and functioning normal liver.

Animals↗
PubMed1990

Prolonged whole body immersion in cold water: hormonal and metabolic changes.

To characterize metabolic and hormonal responses during prolonged whole body immersion, 16 divers wearing dry suits completed four immersions in 5 degrees C water during each of two 5-day air saturation dives at 6.1 meters of sea water. One immersion began in the AM (1000 h) and one began in the PM (2200 h) to evaluate diurnal variations. Venous blood samples were obtained before and after completion of each immersion. Cortisol and ACTH levels demonstrated diurnal variation, with larger increases occurring after PM immersions. A greater than three-fold postimmersion increase occurred in norepinephrine (NE). There were significant increases in triiodothyronine (T3) uptake and epinephrine, but no change in T3, thyroxine, thyrotrophic hormone, and dopamine. Postimmersion free fatty acid levels increased 409% from preimmersion levels; glucose levels declined, and lactate increased significantly. Only changes in NE correlated significantly with changes in rectal temperature. In summary, when subjects are immersed in cold water for prolonged periods, with a slow rate of body cooling afforded by thermal protection and intermittent exercise, hormonal and metabolic changes occur that are similar in direction and magnitude to short-duration unprotected exposures. Except for cortisol and ACTH, none of the other measured variables exhibited diurnal alterations.

Adult↗
PubMed1989

Fluid and cation changes during head-out immersions in 25 degrees and 35 degrees C water.

To compare fluid and ion changes during cold (25 degrees C) and thermoneutral head-out immersion (HOI) 9 men were studied under 4 resting conditions lasting 3 h: 2 in 35 degrees C and 2 in 25 degrees C water. At each temperature, subjects consumed 250 ml of either water or a 7% glucose polymer solution every hour to evaluate possible differences in fluid composition. Plasma volume increased by 3.9% for 35 degrees C and decreased by 9.7% for 25 degrees C HOI after 3 h. Urine flow increased significantly during HOI, but there were no differences between water temperatures (35 degrees C: 8.37 +/- 0.44; 25 degrees C: 9.55 +/- 0.57 ml.min-1). Free water clearance and urinary sodium excretion were also elevated during HOI, but water temperature did not alter the magnitude of the response. No HOI-induced kaliuresis was noted. Finally, there was a significant cold-induced increase in serum potassium and sodium, but this reflected largely the decrease in plasma volume. In sum, differences in water temperature seemed to have minimal influence on fluid and cation changes, an indication that immersion is the primary stimulus. Whether greater differences would be noted with colder water remains to be determined.

Adult↗
PubMed1988

Recurrent femoral anastomotic aneurysms. A 30-year experience.

Of the 1771 patients who underwent aortofemoral bypass grafting (AFB) during the 30-year period of 1957-1986, 43 noninfected recurrent femoral anastomotic aneurysms (RFAA) developed in 28 patients. Thirty-six RFAAs were treated surgically, with one death and no amputations occurring. Seven small RFAAs (less than 2.0 cm) were treated expectantly without complications. Using univariate and multivariate analyses, clinical characteristics and other factors influencing results in patients with RFAAs were compared to two control groups: patients who had undergone AFB without the development of femoral anastomotic aneurysms (FAAs) and patients who had undergone FAA repairs but without recurrence of FAA. Comparative analyses suggested: 1) local wound complications after initial AFB or FAA repair increased risk of a RFAA (p less than 0.03); 2) development of an FAA within 4.5 years after AFB increased risk of a RFAA (p less than 0.0002); 3) following an FAA repair, risk of a RFAA was almost three times greater for women than for men (p less than 0.05); and 4) patients with arteriosclerotic heart disease (ASHD) were less likely to develop RFAA than those without ASHD (p less than 0.05). Among the 20 additional variables analyzed--including hypertension, smoking, diabetes mellitus, and etiology of primary vascular disease--no statistically significant influence on the development of RFAAs could be detected.

Aged↗
PubMed1987

Protection from endotoxemia: a rat model of plasmapheresis and specific adsorption with polymyxin B.

Polymyxin B (PB), a cyclic polypeptide antibiotic, has potent antiendotoxin properties but is associated with significant toxicity when given parenterally. As an alternative, PB was immobilized on a solid phase (Sepharose 4B; Pharmacia, Uppsala, Sweden), and a system of plasmapheresis was developed in the conscious rat, with specific on-line plasma adsorption of endotoxin by a PB-Sepharose column. PB-Sepharose columns removed 94% of a challenge dose of 5 micrograms of endotoxin in vitro. Rats were pretreated with lead acetate so that they were sensitized to endotoxin and then given 10 micrograms of endotoxin/kg intraarterially. After 15 min plasmapheresis was begun and continued for 90 min. Animals whose plasma was perfused over PB-Sepharose were protected from endotoxin-induced leukopenia (P less than .01), thrombocytopenia (P less than .001), and death (four of four survivors compared with none of four controls). Thus plasmapheresis with on-line removal of endotoxin is a safe and highly effective means of protecting animals from the effects of endotoxemia.

Animals↗
PubMed1986

Repeated membrane plasma separation with on-line sorbent treatment of plasma in the conscious rat.

Repeated membrane plasma separation with on-line sorbent treatment of plasma was performed in unrestrained and conscious rats, thus avoiding the possible effects of repeated stress and exposure to anesthetic agents. The procedure was well tolerated, even after four consecutive perfusions. Blood flow was 0.7 ml/min, with a transmembrane pressure of 18.6 mm Hg and plasma filtration rate of 0.21 ml/min. This allowed 12 ml of plasma (greater than 1 plasma volume) to be treated within 1 h. Levels of albumin, immunoglobulin G, and C3 remained constant during each perfusion and were not significantly different from those of animals subjected to control procedures. Results obtained from filtrate were comparable at 15 and 60 min with values obtained from whole blood, with sieving coefficients of approximately 1. Leukocyte, erythrocyte, and thrombocyte counts remained unchanged during each plasma perfusion. A progressive rise in leukocyte counts occurred following successive perfusions, but this was true also of animals subjected to control procedures.

Animals↗
PubMed1986

Preclinical evaluation of haemosorbents.

The selection of assessment procedures for the preclinical evaluation of haemosorbents and the relationship between such procedures and the intended application are exemplified by examination of the design and utilization of procedures based on the rat. Procedures are described for haemoperfusion and for membrane plasma separation followed by on-line sorbent treatment of plasma (plasma perfusion). These procedures are suitable for single or repeated use, with the animal in an unrestrained and conscious state. The relevance to the intended application is demonstrated with respect to artificial liver support by the ability of rat extracorporeal circuits to provide information on the relationship between sorbent properties and liver regeneration as determined by the proliferative response following partial hepatectomy.

Adsorption↗
PubMed1986

Compensatory hyperplasia in the rat liver as a result of cytoplasmic atrophy.

A protracted process of hepatocyte atrophy was induced in the anterior lobes of the rat liver by portal vein ligation (PVL), and within 3 days the combination of atrophy in the anterior lobes and compensatory hyperplasia of the posterior lobes had resulted in the anterior lobes comprising only about 20% of the total liver weight. Apart from an initial fall in the total liver weight due to atrophy of the anterior lobes without any corresponding growth reaction in the posterior lobes, the total liver weight remained close to normal throughout the first 3 days. Surprisingly, increases in posterior lobe DNA synthesis after PVL were triggered almost as rapidly (15-18 h post-operatively) as occurs after anterior lobe resection, though subsequently the level of proliferative activity was generally lower than is found after partial hepatectomy. The rapidity of the proliferative response to PVL suggests the proliferative signal is generated by a minimal cytoplasmic deficit and/or the increased rate of portal blood perfusion.

Animals↗
PubMed1983

Effect of sodium acetate on expression of K99 pili by Escherichia coli.

Sodium acetate suppressed K99 production in Escherichia coli strains cultured on a minimal medium, as determined by seroagglutination and enzyme-linked immunosorbent assay. The greatest suppression occurred when the medium contained both sodium acetate and glucose. Glucose alone did not suppress K99 production.

Acetates↗
PubMed1983

[Possibilities for using extracorporeal circulation in the rat].

An extracorporal system of freely mobile, unanaesthetized rats is presented. This model was used in experiments on the biocompatibility of silicone rubber and new types of hollow membranes. The results confirm a sensitive reaction of haematological parameters to various test substances, thus indicating that the model is very suitable. Carrying out a membrane plasma separation in rats makes it possible also to use rats for studies on detoxification and thus to use the advantages offered by this experimental animal to the full.

Animals↗
PubMed1983

The effect of 5-fluorouracil on DNA synthesis in the rat liver undergoing compensatory hyperplasia after partial hepatectomy.

An investigation has been made into the effects of 5-fluorouracil (5FU) on DNA synthesis after partial hepatectomy. Animals underwent in vivo isolated liver perfusion with 5-fluorouracil followed by partial hepatectomy or Sham hepatectomy. Controls consisted of animals whose liver was perfused with 0.9% saline. Liver weight and DNA synthesis were recorded at various times following 5-fluorouracil perfusion and partial hepatectomy and control procedures. The results have shown that perfusion with large concentrations of the cytotoxic agent (5 FU) can be performed without apparent serious side effects on liver weight and with only minimal delay in liver cell proliferation.

Animals↗
PubMed1982

The effect of repeated hemoperfusion over charcoal in the conscious rat on liver pathophysiology.

An investigation has been made into the effects of repeated charcoal hemoperfusion in the rat on liver pathophysiology. Animals underwent hemoperfusion over Norit RBX1 charcoal using a technique which allowed perfusion in the unrestrained and conscious state, thus minimizing any possible effects from stress and eliminating the necessity of repeated anesthesia. Controls consisted of animals subjected to perfusion through empty columns and animals cannulated only. Liver weight, function, and histology were recorded at various times following hemoperfusion and control procedures. The results show that repeated charcoal hemoperfusion is well tolerated in the rat and can be performed safely with no deleterious effects on liver tissue.

Alanine Transaminase↗
PubMed1982

Hemoperfusion and DNA synthesis in the rat liver. Part I: the effect of hemoperfusion on the rate of DNA synthesis.

An investigation has been made into whether charcoal hemoperfusion stimulates a hyperplastic response in the liver of the normal rat. Animals underwent hemoperfusion over Norit RBX1 (Strathclyde, Glasgow, U.K.) charcoal granules using a technique which allowed perfusion in the unrestrained and conscious state. Controls consisted of animals subjected to perfusion through empty columns and animals cannulated only. Body weight, liver weight, function, and DNA synthesis were recorded at various times after completion of perfusion and control procedures. The results indicated that charcoal hemoperfusion did not stimulate a hyperplastic response in the liver of the normal rat following perfusion, and did not produce marked changes in body weight, liver weight, and function.

Alanine Transaminase↗
PubMed1982

Hemoperfusion and DNA synthesis in the rat liver. Part II: the effect of hemoperfusion on DNA synthesis in the rat liver undergoing compensatory hyperplasia after partial hepatectomy.

An investigation has been made into whether hemoperfusion over activated charcoal effects the rate of DNA synthesis in the rat liver undergoing compensatory hyperplasia. Hemoperfusion was performed in the unrestrained and conscious rat, thus minimizing any possible effects of stress and eliminating exposure to anesthetic agents. The results demonstrate that hemoperfusion over Norit RBX1 charcoal does not influence the liver to undergo compensatory hyperplasia following partial hepatectomy when hemoperfusion is performed immediately after hepatic injury, and that liver mass, function, and fat content consequent upon partial hepatectomy are also not influenced.

Animals↗
PubMed1982

The effect of hemoperfusion over uncoated and polymer-coated charcoal on hematological levels in the conscious rat.

An investigation has been made of the suitability of a rat hemoperfusion system for the evaluation of hematological changes induced by charcoal hemoperfusion. The investigation studied the influence on erythrocyte, leucocyte and thrombocyte levels of repeated hemoperfusion over Norit RBX1 charcoal, hemoperfusion over polymer-coated Norit RBX1 and hemoperfusion over uncoated spherical charcoal. Controls included animals subjected to hemoperfusion through empty columns and animals cannulated only. The results indicate that changes in erythrocyte and leucocyte levels are due principally to passage of blood through the extracorporeal circuit rather than contact with the adsorbent but that changes in thrombocyte levels are dependent on the type of charcoal and the nature and extent of polymer coating. The investigation suggests that the rat hemoperfusion system is a suitable procedure for the assessment of the compatibility of adsorbents to be used in hemoperfusion.

Acrylonitrile↗