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Biomedical subjects

M J Rice

Publications and source records attributed to M J Rice.

At least 73 records · Page 4Linked to original sources
PubMed1985

Effects of hypothermic kidney preservation on the isolated perfused kidney: a comparison of reperfusion methods.

Two isolated-perfused kidney methods were used to study the effects of hypothermic preservation on renal function in dog kidneys. The isolated-machine-perfused kidney (IMPK) used an in vitro perfusion technique--the perfusate was a Krebs-bicarbonate type delivered to the kidney at 37 degrees C by a mechanical pump at a constant pressure (100 mm Hg). The isolated-blood-perfused kidney (IBPK) utilized transplantation of the preserved kidney to the femoral vasculature. Renal function (urine analysis) was determined over a 1-hr reperfusion interval and included GFR (creatinine clearance), urine formation, and Na+ reabsorption. Kidneys preserved for only 24 hr by cold storage in either Collins'--C3 solution or in hypotonic citrate and kidneys hypothermically perfused for 24 hr demonstrated greater retention of renal function when reperfused by blood (IBPK) than with the in vitro perfusate (IMPK). The GFR was reduced by 38-58% when tested with the IBPK, but by 80-90% when tested with the IMPK. Na+ reabsorption was normal (97%) with blood reperfusion but was reduced to 36-50% in cold-stored kidneys and 82% in hypothermically perfused kidneys determined by machine reperfusion (IMPK). However, kidneys perfused for 72 hr demonstrated more similar renal functions when tested by either IMPK or IBPK. GFR was reduced to 20% (IBPK) and 11% (IMPK) and Na+ reabsorption averaged 76-85% (IBPK or IMPK). These results suggest that either reperfusion method is suitable for determining the effects of renal preservation on kidney function in kidneys preserved for 72 hr but, for short-term preserved kidneys (24 hr), the IBPK model may be preferred.

Animals↗
PubMed1985

Results of the modified Fontan operation for congenital heart lesions in patients without preoperative sinus rhythm.

Preoperative sinus rhythm has been a criterion for the Fontan operation. However, of 297 patients who underwent the Fontan operation between October 1973 and February 1984, 12 (4%) did not have sinus rhythm. The age at operation ranged from 4 to 34 years (median 15). Nine patients had a univentricular heart, two had tricuspid atresia and one had a complex form of transposition. In all 12 patients, 3 to 8 of the 10 proposed criteria for operability were not met. An atrioventricular (AV) conduction abnormality was present in seven patients, six with complete AV block and one with AV dissociation. The patient with complex transposition had complete AV block and atrial fibrillation. Postoperatively, all seven patients continued to have an AV conduction abnormality, and those with complete AV block had a permanent pacemaker implanted. Six of the 12 study patients had atrial flutter or fibrillation refractory to antiarrhythmic medications. Postoperatively, four of the six patients had sinus rhythm. Two of the six patients had complete AV block (including the patient with complex transposition) and both had a permanent pacemaker implanted. Three of the 12 patients died (mortality rate 25%). The nine survivors were followed up for 6 to 55 months; no late deaths occurred. All had marked clinical improvement. This study demonstrates that 1) complete AV block is not a contraindication to the Fontan operation, 2) some patients may not require AV synchrony postoperatively for survival, and 3) postoperative atrial flutter or fibrillation may cease or be easier to control after the Fontan operation.

Adolescent↗
PubMed1985

Combination perfusion-cold storage for optimum cadaver kidney function and utilization.

Dog kidneys were perfused with a newly developed perfusate containing adenosine and PO4 for 48 hr, stored in the same perfusate for an additional 24 hr without perfusion (total preservation time:72 hr), and transplanted with immediate contralateral nephrectomy. Posttransplant renal function and biochemical analysis of the kidneys revealed practically no additional preservation-induced damage during the cold storage period. Serum creatinine levels reached normal between the third and eighth day posttransplant. This preservation method may be the method of choice for patients receiving postoperative cyclosporine therapy--and, in addition, facilitate organ sharing between transplant centers, thus reducing wastage of cadaveric kidneys.

Animals↗
PubMed1985

Outcome of the Fontan procedure in patients with tricuspid atresia.

Between 1973 and 1983, 90 patients with tricuspid atresia underwent the Fontan operation at the Mayo Clinic. Operative mortality was 12% overall and decreased to 7% during the second 5 year period. At postoperative follow-up of 65 patients (1 to 10 years, mean 4), 50 (86%) of 58 present survivors were in excellent condition. There had been seven late deaths. Catheterization 0.5 to 8 years (mean 2.7) postoperatively in 25 patients disclosed a mean right atrial pressure of 14 mm Hg (range 6 to 21) and a mean cardiac index at rest of 3.0 (range 1.8 to 4.2). Mean left ventricular end-diastolic pressure was 8.5 mm Hg postoperatively compared with 16.5 mm Hg preoperatively; the decrease was secondary to a decreased ventricular volume load (mean volume load index 10.2 preoperatively, 3.0 postoperatively). We recommend that patients with tricuspid atresia have the Fontan operation by age 6 years to protect myocardial function.

Adolescent↗
PubMed1985

Relationship of pulmonary artery size to mortality in patients undergoing the Fontan operation.

The size of the pulmonary arteries, measured intraoperatively, was correlated with operative mortality in 90 patients who underwent the Fontan operation. There was no significant difference in the cross-sectional area of the right and left pulmonary arteries/body surface area (PA index) between survivors and nonsurvivors. There was no significant difference in mortality rates between patients with a PA index greater than 250 and those with a PA index less than 250 mm2/m2. Survival was observed with cross-sectional area as low as 188 mm2/m2.

Adolescent↗
PubMed1984

Functional single ventricle: cardiorespiratory response to exercise.

The cardiorespiratory response to exercise was measured in 27 children with functional single ventricle. All 27 patients had a significant reduction in exercise time, work performed, maximal exercise heart rate, maximal oxygen uptake and systemic arterial blood oxygen saturation. The reduction in exercise performance increased with increasing age of the patients. All patients ventilated excessively at rest and during exercise. This study documented the precise level of exercise intolerance in patients with functional single ventricle. The progressive deterioration in exercise performance with increasing patient age may lend credence to the concept that operation for physiologic correction of functional single ventricle should be considered during or before adolescence.

Adolescent↗
PubMed1983

Impact of 2-Dimensional echocardiography on the management of distressed newborns in whom cardiac disease is suspected.

The course and management of 40 consecutive newborns (aged less than 2 weeks) who presented with signs and symptoms of congenital heart disease were reviewed to determine the impact of 2-dimensional (2-D) echocardiography on their subsequent management. Of the 40 patients with congenital heart disease, 60% did not undergo cardiac catheterization. Forty-two percent of the patients who were treated surgically went directly to operation without preoperative cardiac catheterization. Only 40% of the patients with congenital heart disease required cardiac catheterization in the newborn period, and 43% of these procedures were primarily therapeutic (that is, balloon atrial septostomy). In each patient 2-D echocardiography correctly identified the major cardiac malformation and there was good agreement with angiographic, surgical, and autopsy findings. The most commonly overlooked defect was a patent ductus arteriosus. Thus, 2-D echocardiography not only allows diagnosis of congenital heart disease in the newborn but can expedite clinical management. No longer is cardiac catheterization necessarily the primary means for an anatomic diagnosis of congenital cardiac malformations in the newborn.

Angiography↗
PubMed1983

Left juxtaposed atrial appendages: diagnostic two-dimensional echocardiographic features.

Left juxtaposition of the atrial appendages is usually associated with cyanotic congenital heart disease. Recognition of this rare anomaly is important before therapeutic or surgical procedures that involve the atrial septum can be undertaken (for example, septostomy, the Mustard or Senning operation and the Fontan anastomosis). The diagnosis of left juxtaposition of the atrial appendages is most commonly an incidental finding at the time of surgery or autopsy. This report describes the two-dimensional echocardiographic visualization of left juxtaposed atrial appendages. The diagnostic echocardiographic features are based on characteristic alterations of the plane of the atrial septum and visualization of the malpositioned right atrial appendage. On the basis of these observations, a noninvasive diagnosis of left juxtaposed atrial appendages is now possible by means of two-dimensional echocardiography.

Adolescent↗
PubMed1981

Comparison of the codon recognition properties and of the utilization of normal and tumor specific Phe-tRNAs in protein synthesis.

Phe-tRNA from normal rat liver (designated Phe-tRNAN) and the under-modified, tumor specific, Phe-tRNAs from mouse neuroblastoma (designated Phe-tRNANB) and rat lymphoma (designated Phe-tRNARL) recognize the phenylalanine codons, UUU and UUC in a ribosome binding assay, but not other codons that differ from UUU and UUC in a single base at either the 5' or 3' position. Phe-tRNANB was incorporated into protein more extensively than either Phe-tRNARL or Phe-tRNAN in wheat germ extracts programmed with globin mRNA. The utilization level of each Phe-tRNA was correlated with its rate of deacylation in wheat germ extracts, i.e., Phe-tRNANB deacylated less rapidly than Phe-tRNARL or Phe-tRNAN. Phe-tRNA, from which the Y base was chemically excised (designated Phe-tRNA-Y), did not respond to UUU or UUC in the ribosomal binding assay, nor did it transfer its phenylalanine to protein in wheat germ extracts programmed with globin mRNA.

Animals↗
PubMed1979

Rheumatic fever in Minnesota. II. Evaluation of hospitalized patients and utilization of a State Rheumatic Fever Registry.

We studied the hospital records of 124 patients with a discharge diagnosis of acute rheumatic fever who were hospitalized in 21 Minneapolis-St. Paul hospitals during 1975 and 1976. After careful review of the hospital records, we found that 83 (67 per cent) of these patients did not have an acute illness. Seventeen (41 per cent) of the 41 cases with an acute illness were thought to adequately fulfill the Jones' Criteria for acute rheumatic fever. Upon review of the rheumatic fever registry of the Minnesota State Health Department, we found that less than one-half of the hospitalized patients had been reported to the registry. Cases that fulfilled and did not fulfill the Jones' Criteria were reported with equal frequency, indicating significant underreporting and overreporting of rheumatic fever. Evaluation of secondary rheumatic fever prophylaxis, both in those patients with acute rheumatic fever as well as in those with rheumatic heart disease, indicated that many patients who, in theory, should be receiving prophylaxis were not receiving it. These studies indicate a need for more thorough evaluation of the current epidemiology of rheumatic fever and the role of a rheumatic fever registry, and imply a need for reevaluation of these programs. (Am J Public Health 69:767-771, 1979).

Acute Disease↗