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Biomedical subjects

J E Carter

Publications and source records attributed to J E Carter.

At least 109 records · Page 6Linked to original sources
PubMed1982

Sudden visual loss and a chiasmal syndrome due to an intrachiasmatic vascular malformation.

A 48-year-old woman presented with a chief complaint of visual loss and bitemporal hemianopia. A similar episode of temporal visual field loss had occurred 34 months earlier and spontaneously resolved. Computerized tomography demonstrated a suprasellar mass. Angiography was normal. At surgery a venous angioma of the optic chiasm with a fresh hematoma was found and removed. Intrachiasmatic vascular malformation is an unusual finding which should be considered in the differential diagnosis in patients with a chiasmal syndrome.

Cranial Nerve Diseases↗
PubMed1982

Chlorpropamide-induced optic neuropathy.

A 65-year-old woman with adult-onset diabetes treated with chlorpropamide (Diabenese) had a toxic optic neuropathy that resolved with discontinuation of chlorpropamide therapy. Visual loss occurs in diabetics for a variety of reasons, and accurate diagnosis is necessary to institute appropriate therapy. The possibility of a drug-induced optic neuropathy should be considered in the differential diagnosis of visual loss in diabetics.

Aged↗
PubMed1981

High-performance liquid chromatographic determination of sodium nitroprusside.

A rapid high-performance liquid chromatographic method for the determination of nitroprusside in commercial lyophilized products or in intravenous admixture solutions is described. The method is stability-indicating. Reversed-phase liquid chromatography was performed using a microparticulate (10 micrometer) phenyl column with a mobile phase acetonitrile--phosphate/tetrabutylammonium hydroxide buffer (pH 7.1) (30:70) and detection at 210 nm. A coefficient of variation of less than 3.1% was achieved over the concentration range studied (10--50 microgram/ml). Total analysis time was 9 min. This method was used to show that there is a small loss of nitroprusside due to photodegradation during intravenous infusion, even when the admixture container is wrapped in foil as recommended and used expeditiously.

Chromatography, High Pressure Liquid↗
PubMed1981

Mitral valve replacement for isolated mitral regurgitation: analysis of clinical course and late postoperative left ventricular ejection fraction.

One hundred five patients underwent mitral valve replacement for relief of isolated mitral regurgitation between 1974 and 1979. There were 4 in-hospital deaths (4 percent) and 12 late deaths giving an 82 percent predicted 5 year survival rate. An age of 60 years or more at the time of surgery and a preoperative left ventricular ejection fraction of less than 0.40 were the only variables that correlated with decreased survival at 3 to 5 years after operation (p less than 0.05). Postoperatively, 87 (98 percent) of 89 long-term survivors were in New York Heart Association functional class I or II (68 in class I and 19 in class II). Survival did not differ between patients with porcine versus mechanical valve replacement, but patients with a mechanical valve had a greater incidence of postoperative cerebrovascular accident (8.6/100 patient years) than did patients with a porcine valve (2.8/100 patient years) (p less than 0.002). Ejection fraction at rest was determined with multigated cardiac imaging 12 to 75 months postoperatively in 34 of 89 long-term survivors. The mean preoperative ejection fraction was 0.62 +/- 0.09 (mean +/- 1 standard deviation) and the mean postoperative ejection fraction was 0.50 +/- 0.15 (p less than 0.001). When the preoperative value was compared with the postoperative value at rest the ejection fraction increased by 0.10 or more in 1 patient (3 percent), remained within +/- 0.09 of the preoperative value in 12 patients (35 percent) and decreased by 0.10 or greater in 21 patients (62 percent). Sixteen (94 percent) of 17 patients whose postoperative ejection fraction was greater than 0.50 were in functional class I postoperatively compared with 11 (65 percent) of 17 patients whose postoperative ejection fraction was 0.50 or less (p less than 0.05). No preoperative factor, including preoperative ejection fraction or cardiothoracic ratio, predicted the postoperative ejection fraction. A postoperative exercise ejection fraction was obtained in 29 patients, and an abnormal ejection fraction change with exercise (increase less than 0.05) was observed in 20 patients (69 percent). Patient age at the time of study correlated inversely with the change in ejection fraction from rest to exercise; no other variables were predictive. It is concluded that, in addition to age, only preoperative left ventricular function as measured by ejection fraction predicts survival in patients undergoing mitral valve replacement for isolated mitral regurgitation. Clinical recovery is good even though the majority of long-term survivors have a postoperative decrease in ejection fraction.

Aged↗
PubMed1981

The effect of pulsatile perfusion on preservation of left ventricular function after aortocoronary bypass grafting.

Pulsatile perfusion has been reported to be of value in intraoperative myocardial protection. To evaluate this technique, we studied 26 patients undergoing aortocoronary bypass grafting. Ejection fraction determinations from multigated cardiac blood pool scans, serial hemodynamic monitoring, and total CPK and MB-CPK sampling were performed early (4, 6 and 8 hours after bypass) and 10 days after operation. In 12 patients, pulsatile perfusion was started immediately after aortic cannulation and continued until 10 minutes after cessation of bypass; 14 patients had standard nonpulsatile perfusion. All patients had a single aortic cross-clamping and potassium cardioplegia. Cross-clamp time (46 +/- 3 and 46 +/- 3 minutes [+/- SEM]), total bypass time (94 +/- 4 and 89 +/- 6 minutes), and mean perfusion pressure (82 +/- 5 and 83 +/- 3 mm Hg) were comparable in the pulsatile and nonpulsatile groups, respectively, as were extent of coronary disease and number of bypass grafts. Preoperative and postoperative ejection fractions for pulsatile and nonpulsatile groups, respectively, were 0.57 +/- 0.03 and 0.55 +/- 0.04 before operation, 0.37 +/- 0.03 and 0.40 +/- 0.04 4 hours after bypass, 0.40 +/- 0.03 and 0.46 +/- 0.04 at 6 hours, 0.51 +/- 0.05 and 0.52 +/- 0.07 at 8 hours and 0.56 +/- 0.05 and 0.53 +/- 0.04) 10 days after operation. Mean arterial pressure, left atrial pressure and serial cardiac indexes were similar in both groups. There were no perioperative myocardial infarctions by ECG in either group. Total CPK (586 +/- 78 and 617 +/- 140 IU/l) and peak MB-CPK (73 +/0 14 and 61 +/- 11 IU/l) were comparable in the pulsatile and nonpulsatile groups, respectively. Pulsatile perfusion offers no advantage in myocardial preservation after aortocoronary bypass grafting in patients with normal left ventricular function.

Coronary Artery Bypass↗
PubMed1981

Hemodynamic and clinical evaluation of the Hancock modified-orifice aortic bioprosthesis.

Clinical experience with the Hancock porcine bioprosthetic heart valve was reviewed in 150 consecutive patients (82 men and 69 women), 13-83 years of age (mean 65 years and 65% older than 60 years), who underwent aortic valve replacement from February 1977 to December 1979. Thirty-eight percent of the patients had associated procedures, including aortocoronary bypass grafting (CABG), valvuloplasty and multiple valve replacement. Overall early mortality was 5% (eight of 150 patients): three of 98 who had isolated aortic valve replacement (AVR), two of 21 who had aortic and mitral valve replacement (AVR/MVR), one of 26 who had AVR/CABG and two four who had AVR/MVR/CABG. In a follow-up period of 6-42 months (mean 26 months), 10 patients have died. Predicted 3-year survival for the study population was 80%. Ninety percent of surviving patients in New York Heart Association functional class I. Incidence of emboli has been 1.5/100 patient-years. Of the five cases of endocarditis, three were fatal and all required reoperation. There have been no primary valve failures. In 43 patients, transvalvular intraoperative peak systolic gradients (left ventricular to aorta) were measured. In those with 19-mm valves (two patients), the gradient was 12.5 +/- 3.5 mm Hg; in those with 21-mm valves (16 patients), it was 10.0 +/- 6.5 mm Hg; in those with 23-mm valves (18 patients), it was 10.8 +/- 5.9 mm Hg; and in those with 25-mm valves (seven patients), it was 9.8 +/- 5.8 mm Hg. Thus, the Hancock modified orifice valve has good hydraulic performance and a low embolic rate without the need for anticoagulation, so it is acceptable for the elderly patient with a small aortic root.

Adolescent↗
PubMed1981

Hemodynamic evaluation of Hancock and Carpentier-Edwards bioprostheses.

The Hancock (H) and Carpentier-Edwards (CE) porcine xenografts are the most commonly used bioprostheses hemodynamic performance of these valves at each valve size was assessed by intraoperative measurement of transvalvular gradients and cardiac outputs in 122 patients undergoing aortic or mitral valve replacement. At comparable cardiac outputs, peak aortic valve gradients (+/- DS) were: 23-mm valve - H (modified orifice) 10.8 +/- 5.9 mm Hg, CE 7.6 +/- 6.2 mm Hg; 25-mm valve - H 11.9 +/- 5.5 mm Hg, CE 8.3 +/- 5.9 mm Hg; 27/29-mm valve - H 11.0 +/- 6.0 mm Hg, CE 6.6 +/- 5.0 mm Hg. Mitral valve gradients were: 29-mm valve - H 3.7 +/- 1.2 mm Hg, CE 2.8 +/- 1.1 mm Hg; 31-mm valve - H 3.5 +/- 1.0 mm Hg, CE 2.6 +/- 0.7 mm Hg, 33/35-mm valve - H 3.2 +/- 1.9 mm Hg. In both the mitral and aortic positions, Carpentier-Edwards porcine bioprostheses had significantly lower (p less than 0.01 and P less than 0.05, respectively) transvalvular gradients than Hancock porcine xenografts.

Aortic Valve↗
PubMed1980

GLC determination of bretylium in biological fluids.

Bretylium [(o-bromobenzyl)ethyldimethylamine] is a quaternary ammonium compound used as the tosylate salt for treatment of ventricular fibrillation in humans. A sensitive assay was developed for the determination of low bretylium concentrations in plasma and urine. The internal standards were (p-bromobenzyl)ethyldimethylammonium p-toluenesulfonate and (o-methoxybenzyl)ethyldimethylammonium p-toluenesulfonate. Samples were deproteinized with acetonitrile and extracted with methylene chloride. After the evaporation of the organic phase, the residue was reacted with sodium 2,4,5-trichlorothiophenolate in methanol. This procedure yielded volatile compounds with excellent electron-capture capabilities for the GLC analysis. The assay sensitivity is 5 ng/ml. The extraction recovery of bretylium as determined by a direct radioactivity measurement was 90 and 97% for plasma and urine, respectively. The method is highly reproducible with no significant day-to-day variations. Comparisons of 60 standard plasma samples, 25 standard urine samples, and plasma samples from a dog that received [14C]bretylium showed excellent agreement between the GLC method and direct radioactivity measurement of bretylium.

Animals↗
PubMed1980

Evaluation of sustained-action chlorpheniramine-pseudoephedrine dosage form in humans.

This investigation compared the bioavailability of chlorpheniramine and pseudoephedrine from a sustained-action capsule and a combination of two reference standard tablets in 24 normal human subjects. The capsule contained 8 mg of chlorpheniramine maleate and 120 mg of pseudoephedrine hydrochloride, and the tablets each contained half of the amount of the chlorpheniramine or pseudoephedrine in the capsule. Because the capsule was a combination product, a new study design had to be developed to accommodate steady-state conditions for both drugs. Each subject received the capsule (every 12 hr) and the combination of the reference tablets (every 6 hr) for 8 days according to a two-way crossover design. Serial blood and urine samples were taken during the entire study. Plasma and urine samples were assayed for chlorpheniramine and pseudoephedrine by sensitive and specific high-pressure liquid chromatographic or GLC methods. There were no significant differences in the plasma concentration profiles of chlorpheniramine and pseudoephedrine at all times, except when the capsule developed peaks or the tablets developed nadirs. The highest mean peak plasma concentrations for the capsule and the tablets were 38.7 and 32.9 ng of chlorpheniramine/,ml and 525 and 515 ng of pseudoephedrine/ml, respectively. The mean biological half-lives of chlorpheniramine and pseudoephedrine were 21.6 and 8.0 hr, respectively. The AUC and unchanged drug excreted in urine, after a single dose and at steady state, showed that the sustained-action capsule (given every 12 hr) and the reference standard tablets (given every 6 hr) were bioequivalent.

Adult↗
PubMed1980

Analysis of procainamide hydrochloride and acecainide hydrochloride in rat feed.

An extraction and GLC assay procedure was developed for quantitation of procainamide hydrochloride and acecainide hydrochloride in rat feed. 4-Amino-N-[2-(dipropylamino)ethyl]benzamide hydrochloride was synthesized and utilized as an internal standard. The assay has good precision and accuracy and was used to establish the stability of acecainide hydrochloride and procainamide hydrochloride in rat feed.

Acecainide↗
PubMed1980

The effects of anabolic steroids on growth, body composition, and metabolism in boys with chronic renal failure on regular hemodialysis.

Eight boys aged 9.5 to 17 years, on regular hemodialysis for chronic renal failure, were treated for 0.4 to 1.3 years with the anabolic steroid oxandrolone. The effects on linear growth, skeletal maturation, cell mass, and the fasting levels and response to intravenous glucose of BG, IRI, NEFA, BCAA, and IRG were measured. Following treatment there was a significant increase in mean growth velocity, growth velocity standard deviation score related to bone age, and cell mass. Overall skeletal maturation was not accelerated, and only a small advance in pubertal status was seen. There was a decrease in fasting levels of BG and NEFA; fasting BCAA and IRG were increased. The response to intravenous glucose was altered; there was a decrease in peak BG response, an increase in peak IRI response, and a more marked fall in plasma NEFA and BCAA levels. Fasting IRG levels correlated with fasting BG levels, and fell significantly following intravenous glucose both before and after treatment. Hepatotoxicity, which was reversible, was seen in a ninth boy who did not complete the study. The only other side effect, salt and water retention, was controlled by a reduction in oxandrolone dosage. These preliminary results suggest that anabolic steroids may be useful to stimulate anabolism and growth in uremic children, and that their effect is mediated by an increase in insulin secretion and/or an improvement in tissue sensitivity to insulin. Further studies with careful monitoring are required to substantiate the effect on final height and the risks involved.

Adolescent↗
PubMed1980

10 years' experience with regular haemodialysis and renal transplantation.

75 children aged under 15 years have entered the regular haemodialysis/renal transplant programme at Guy's Hospital in the 10 years since its inception; 13 children have subsequently died. A combination of hospital and home haemodialysis and renal transplantation was used. 64 children received 80 renal allografts; 37 1st grafts were from live, related donors and 27 were from cadaver donors. The 5-year acturial patient survival for the whole group and for those who had transplants was 76%. Live donor graft survival was 65% at 3 years, and 55% at 5 years; 1st cadaver graft survival was 42% at 3 years. Results obtained during the last 6 years of the 10-year period showed an improvement with a live related donor graft survival rate of 71%, and a 1st cadaver graft survival rate of 47% at 3 years. Particular experience was gained with home haemodialysis and live, related donor transplantation. Despite growth, and psychosocial and rehabilitation problems, the overall results were encouraging, particularly for the 46 children who had successful transplants. These children grew better, had fewer psychosocial difficulties, and were rehabilitated more successfully into normal life than those on long-term dialysis. We conclude that dialysis and transplantation should be offered to all suitable children with terminal renal failure.

Adolescent↗