Biomedical subjects
M Jones
Publications and source records attributed to M Jones.
Evaluation of follow-up methods to detect relapse after mastectomy in breast cancer patients.
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The case for preoperative coronary angiography in patients with tetralogy of Fallot and other complex congenital heart diseases.
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Late results after operations for left ventricular outflow tract obstruction.
The late results were evaluated of operations for the relief of left ventricular outflow tract obstruction in young patients, 1 to 18 years old, from the National Heart Institute who were followed up for at least 5 years and from recently reported studies with an average follow-up duration of 5 or more years. The operative mortality rate for the combined series was low: 1.9 percent of 522 patients with valvular aortic stenosis, 6.0 percent of 222 patients with fixed subvalvular aortic stenosis and 5.5 percent of 18 patients with hypertrophic subaortic stenosis. From the National Heart Institute series, gradients early postoperatively were decreased to less than 50 mm Hg in 88 percent (30 of 34) of patients with valvular, in 68 percent (15 of 22) of patients with subvalvular and in 88 percent (8 of 9) of patients with hypertrophic subaortic stenosis. Late survival rates for patients in the combined series were 90 percent (472 of 522), 86 percent (190 of 222), and 82 percent (14 of 17) in the three respective groups after mean follow-up periods of 5 to 14.4 years. All late survivors in the current series have had symptomatic improvement; 95 percent (58 of 61) are asymptomatic. However, actuarial analysis in these patients predicts that 50 +/- 8 percent of those with valvular and 44 +/- 10 percent of those with subvalvular aortic stenosis after 10 years will be free from the adverse postoperative events of residual or recurrent left ventricular outflow tract obstruction, clinically significant aortic regurgitation, reoperation, endocarditis or late death. With use of the same adverse postoperative events to determine satisfactory late results from the combined series, it was found that 54 percent (281 of 522) of those operated on for valvular, 54 percent (120 of 222) of those operated on for subvalvular and 78 percent (14 of 18) of those operated on for hypertrophic subaortic stenosis had satisfactory late results 5 to 14 years after operation. Of the patients having unsatisfactory late results, major hemodynamic abnormalities were detected in 55 percent (23 of 42) within 1 year postoperatively. Thus it appears that operations for many children with left ventricular outflow tract obstruction are palliative. These patients should have early postoperative assessment and continuing long-term follow-up evaluation during childhood, adolescence and adulthood.
A biochemical investigation of spinal cord after contusive injury.
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A micromethod for the determination of ceramide.
An enzymatic micromethod for the determination of ceramide is presented. The enzyme, E. coli diglyceride kinase was used to phosphorylate ceramide, as well as diglyceride with high specific activity gamma-[32P]ATP, and the two products are differentiated by their alkali stability. This method was applied to the detection of endogenous phospholipases and sphingolipases in several membrane systems and could have wide application.
Sucrose polyester and covert caloric dilution.
Total daily caloric intake was measured in 10 obese subjects when sucrose polyester (SPE), a nonabsorbable synthetic fat, covertly replaced conventional fats in a single crossover study consisting of three periods: a period of 7 to 14 days to determine baseline caloric intake and two 20-day study periods. An average of 60 g SPE/day replaced conventional fat in one of the two study periods. During both study periods, 60% of the base line caloric intake was "required intake" at mealtime; an additional 60% of base line caloric intake was allowed as "free choice" foods at a specified snacktime. It was thus possible during both study periods to consume more than 100% of the base line caloric intake. In the SPE study period, 40 g SPE replaced 40 g conventional fat for every 1200 kcal of required intake, resulting in a 30% reduction in mealtime caloric intake. Mean total caloric intake (meal and snack) fell 23% during the SPE period (p less than 0.05), despite an average daily weight loss of 0.18 kg. Snack caloric intake did not increase significantly to compensate for caloric dilution of the meals during the SPE period. These results indicate that the obese may not detect or may not compensate for covert dilution of fat calories with SPE. In addition, during the SPE period, there was a 10% reduction in total plasma cholesterol, a 14% reduction in low-density lipoprotein cholesterol, and a 10% reduction in triglyceride concentration. Thus, fat replacement with SPE may benefit weight reduction regimens in obese subjects by facilitating decreased caloric intake and by improving the circulating lipoprotein profile as well.
Isolation and properties of isolated nuclei from the Florida red tide dinoflagellate Gymnodinium breve (Davis).
A simple and rapid method is described for the isolation of nuclei from the Florida red tide dinoflagellate Gymnodinium breve. The nuclei are free of cytoplasmic contamination and are active in endogenous RNA synthesis. The ratio of DNA : RNA : acid-soluble protein : acid-insoluble protein is 1:0.39:0.13:0.63, respectively, and each nucleus contains ca. 113 picograms of DNA. Electrophoretic analysis of the acid-soluble proteins reveals the presence of two histone-like proteins with molecular weights of 12,000 and 13,000.
Metabolic and health consequences of occupational exposure to polychlorinated biphenyls.
In surveys of three groups of workers occupationally exposed to polychlorinated biphenyls (PCBs) serum PCB concentrations were quantitated as lower chlorinated biphenyls (L-PCBs) and higher chlorinated biphenyls (H-PCBs). Serum L-PCB and H-PCB concentrations were many times greater among workers employed in power capacitor manufacturing than exposed areas. Statistically significant positive correlations of symptoms suggestive of mucous membrane and skin irritation, of systemic malaise, and altered peripheral sensation were noted with increasing concentrations of serum PCB. No clinical abnormalities attributable to exposure to PCB were observed. Serum PCB concentrations were positively and significantly correlated with glutamic-oxalacetic transaminase (SGOT), serum gamma-glutamyl transpeptidase (GGTP), and plasma triglyceride, and inversely correlated with plasma high density lipoprotein-cholesterol. These correlations were present across all study sites. These findings are indicative of PCBs' physiological effect on the liver, whose long-range health significance is unknown. Nevertheless, the consistent positive association of serum PCB with plasma triglyceride and negative association with plasma HDL-cholesterol may have long-term cardiovascular consequences.
Left atrial-to-right atrial shunt without atrial septal defect or precordial murmur. Pulmonary varix and hypertrophic cardiomyopathy.
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Is the use of phenolics essential in hospital cleaning?
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The biggest contraceptive in the world.
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Regional myocardial blood flow in left ventricular hypertrophy. An experimental investigation in Newfoundland dogs with congenital subaortic stenosis.
To test the hypothesis that left ventricular hypertrophy (LVH) may predispose the subendocardium to ischemia, we studied regional myocardial blood flow in dogs with the fibrous ring form of subvalvular aortic stenosis and concentric LVH. Radioactive microspheres, 9 +/- 1 mu in diameter, were used. Eleven dogs with LVH (left ventricular body weight ratio of 6.35 +/- 0.46 gm/kg [mean +/- SEM] and peak left ventricular outflow gradient of 51 +/- 7 mm Hg) were compared to 12 normal dogs (left ventricular/body weight ratio of 3.41 +/- 0.12 gm/kg and peak left ventricular outflow gradient of 6 +/- 3 mm Hg). The two groups of dogs were subjected to comparable experimental interventions including (1) tachycardia produced by atrial pacing (221 +/- 4 beats/min), (2) ascending aortic constriction producing systolic hypertension (212 +/- 5 mm Hg), and (3) creation of an aortic-right atrial fistula lowering diastolic blood pressure (38 +/- 3 mm Hg). Basal regional myocardial blood flow was distributed similarly for LVH and normal dogs (endocardial/epicardial ratio = 0.90 +/- 0.05 and 0.94 +/- 0.03, respectively). During experimental interventions, regional blood flow remained equal to all myocardial layers in normal dogs; however, the endocardial/epicardial ratio diminished in LVH dogs during atrial tachycardia to 0.61 +/- 0.08, during systolic hypertension to 0.68 +/- 0.06, and during diastolic hypotension to 0.50 +/- 0.09. When the diastolic/systolic pressure time index ratio (DPTI/SPTI) was less than 0.8, subendocardial ischemia occurred in dogs with LVH (endocardial/epicardial ratio = 0.66 +/- 0.04) but not in normal dogs (endocardial/epicardial ratio = 0.92 +/- 0.03) (p less than 0.0001). Animals with infracoronary obstruction and LVH demonstrate greater susceptibility to development of subendocardial ischemia for identical hemodynamic interventions than do normal animals.
Residual shunting in the early postoperative period after closure of atrial septal defect: echocardiographic comparison of patch materials.
Residual shunting after surgical closure of septal defects is a common postoperative complication. In this study, contrast echocardiography was used to assess the effect of different surgical patch materials on early postoperative residual shunting. The study consisted of 44 patients (aged 3 days to 64 years) with simple or complex atrial septal defects. Total pulmonary-to-systemic flow ratios ranged form 1.8:1 to 4.0:1. Three methods were used to close the atrial septal defects: primary suture closure (n = 7), patching with thin, knit Teflon fabric (n = 13), and patching with thicker, low porosity, knit Teflon fabric (n = 24). Contrast echocardiographic injections were performed through central venous and left atrial lines positioned at operation for monitoring purposes. Ten of the 44 patients had residual shunts. In five of them, daily contrast studies showed progressive diminution in shunting with eventual resolution, but in the other five patients, shunting persisted beyond the first 5 postoperative days. Three of the latter five required reoperation for actual residual anatomic defects. No patient whose atrial septal defect was closed by either direct suture or thick, low porosity Teflon fabric had shunting detected at any time postoperatively. Our data confirmed temporary leakage across newly implanted intracardiac patches. However, shunts that persist beyond the first postoperative week indicate true anatomic residua and not porous patch material. If a patient's recovery is complicated, use of contrast echocardiography can determine whether a residual shunt is a causative factor. In patients with complex lesions in whom continued shunting during the early postoperative period may cause serious hemodynamic consequences, heavier, low porosity patch material can be useful.
Inward stent-post bending of a porcine bioprosthesis in the mitral position: cause of bioprosthetic dysfunction.
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Degeneration and calcification of bioprosthetic cardiac valves. Bioprosthetic tricuspid valve implantation in sheep.
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Intracuspal hematomas in implanted porcine valvular bioprostheses: clinical and experimental studies.
Intracuspal hematomas were found in three of 57 porcine valvular bioprostheses implanted as substitute cardiac valves in 50 patients and in 11 of 29 similar bioprostheses implanted in sheep. The three values implanted in patients had been in the mitral position for 27, 65, and 107 months. Of the valves implanted in sheep, six had been in the mitral position and five in the tricuspid position for periods of time ranging from 20 minutes to 7 months. In each patient and in four of 11 sheep, the hematomas involved more than one cusp. These lesions were localized in the spongiosa, extended from the basal region toward the free edge of the cusp, and formed a plane of dissection which involved the spaces left in the spongiosa by the removal of proteoglycan material during preimplantation commercial processing. In one patient, the hematomas limited the mobility of the cusps and appeared to have been the cause of clinically significant prosthetic mitral stenosis; in the other two patients and in the experimental animals, the hematomas were smaller and of uncertain hemodynamic significance. Intracuspal hematomas may become sites of eventual formation of calcific deposits. The pathogenesis of intracuspal hematomas is related to the entry of blood into the space between the sewing ring and the most basilar region of the bioprosthetic tissue. This space extends throughout the circumference of the bioprosthesis and is continuous with the spongiosa, the layer in which the hematoma develops. The blood penetrates into this space through the suture line between bioprosthetic tissue and sewing ring on the inflow surface of porcine valvular bioprostheses which have been mounted on atrioventricular type stents. Intracuspal hematomas were not found in bioprostheses mounted on aortic type stents, in which these sutures are more protected and more closely spaced, or in pericardial bioprostheses, which do not have a spongiosa.
Bioprosthetic valvular failure. Clinical and pathological observations in an experimental animal model.
We compared the clinical, hemodynamic, and morphological findings in 18 young sheep in which porcine valvular bioprosthesis (eight animals) and bovine pericardial bioprostheses (10 animals) were implanted in the tricuspid position. At the time of terminal elective studies (mean of 5.2 +/- 0.2 months after implantation), six animals had ascites, 16 had hepatic congestion, and four had bioprosthetic valvular infection. Hemodynamic studies (n = 10) showed that the tricuspid transvalvular mean diastolic gradients were not different at implantation and at termination of the study (4.7 +/- 0.8 versus 4.9 +/- 0.9 mm Hg); however, tricuspid valve end-diastolic gradients increased from 1.2 +/- 0.6 to 3.9 +/- 0.5 mm Hg (p less than 0.01). Each of the 18 valves had calcific deposits. Quantitative studies revealed that implanted porcine valvular bioprosthesis (n = 7) contained a mean of 323 +/- 165 mg of calcium/gm of dry weight of cuspal tissue, in contrast to 0.2 mg/gm in unimplanted porcine valvular prostheses. Similarly, implanted bovine pericardial bioprostheses (n = 6) contained a mean of 421 +/- 115 mg of calcium/gm of dry weight of cuspal tissue, in contrast to 0.3 mg/gm im unimplanted bovine pericardial bioprostheses. Morphological findings in both types of bioprostheses included calcific deposits, collagen degeneration, leaflet immobilization and retraction, and fibrous sheaths. The latter were more extensive in bovine pericardial bioprostheses than in porcine valvular bioprostheses. We conclude: (1) that the pathological alterations which develop in bovine pericardial bioprostheses are generally similar to those in porcine valvular bioprostheses, but may be more severe; (2) that these alterations lead to physiological and clinical sequelae similar to those of bioprosthetic valvular failure in human subjects; and (3) that young sheep constitute an excellent experimental model for in vivo testing of bioprosthetic cardiac valves.