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Biomedical subjects

R Adar

Publications and source records attributed to R Adar.

At least 73 records · Page 4Linked to original sources
PubMed1989

A confidence profile analysis of the results of femoropopliteal percutaneous transluminal angioplasty in the treatment of lower-extremity ischemia.

The many reports on the use of percutaneous transluminal angioplasty (PTA) for treating lower-extremity ischemia were analyzed to determine the outcomes of femoropopliteal PTA used in patients with intermittent claudication (IC) and with more severe limb-threatening ischemia ("salvage"). The Confidence Profile Method was used to interpret and adjust the evidence from 12 selected clinical reports, and to combine the data into single best estimates of the outcomes that were considered important for decision making. The following combined estimates were obtained: The early success rate was 89% +/- 2.5% after PTA for IC, compared with 77% +/- 4% after PTA for salvage. The largest decline in patency occurred during the first 6 to 12 months. After 2 years there was little further attrition. Three-year patency was 62% +/- 9% for IC and 43% +/- 7% for salvage. The risk of procedure-related mortality and limb loss was low, estimated at 0.5% and 1%, respectively. The risk of serious complications requiring surgical repair was about 2.5%. The Confidence Profile Method is a novel way of obtaining this information from the imperfect clinical literature. The method incorporates subjective judgments and assumptions and gives quantitative and visual representations of both the magnitude of the estimated outcome and the uncertainty associated with it. The results are as strong as the assumptions incorporated in them are valid. The estimates derived in this study can be used for any decision on the use of PTA in the femoropopliteal segment.

Angioplasty, Balloon↗
PubMed1989

Inhibitory activity of cranberry juice on adherence of type 1 and type P fimbriated Escherichia coli to eucaryotic cells.

Inhibition of bacterial adherence to bladder cells has been assumed to account for the beneficial action ascribed to cranberry juice and cranberry juice cocktail in the prevention of urinary tract infections (A. E. Sobota, J. Urol. 131:1013-1016, 1984). We have examined the effect of the cocktail and juice on the adherence of Escherichia coli expressing surface lectins of defined sugar specificity to yeasts, tissue culture cells, erythrocytes, and mouse peritoneal macrophages. Cranberry juice cocktail inhibited the adherence of urinary isolates expressing type 1 fimbriae (mannose specific) and P fimbriae [specific for alpha-D-Gal(1----4)-beta-D-Gal] but had no effect on a diarrheal isolate expressing a CFA/I adhesin. The cocktail also inhibited yeast agglutination by purified type 1 fimbriae. The inhibitory activity for type 1 fimbriated E. coli was dialyzable and could be ascribed to the fructose present in the cocktail; this sugar was about 1/10 as active as methyl alpha-D-mannoside in inhibiting the adherence of type 1 fimbriated bacteria. The inhibitory activity for the P fimbriated bacteria was nondialyzable and was detected only after preincubation of the bacteria with the cocktail. Cranberry juice, orange juice, and pineapple juice also inhibited adherence of type 1 fimbriated E. coli, most likely because of their fructose content. However, the two latter juices did not inhibit the P fimbriated bacteria. We conclude that cranberry juice contains at least two inhibitors of lectin-mediated adherence of uropathogens to eucaryotic cells. Further studies are required to establish whether these inhibitors play a role in vivo.

Agglutination↗
PubMed1989

Errors and pitfalls in intraarterial thrombolytic therapy.

Sixty complications occurred during 138 courses of intraarterial thrombolytic therapy in 122 patients during a 5-year period. These complications were recorded and analyzed prospectively to identify underlying errors in management. There were 31 bleeding episodes, 15 vascular complications, and 14 other complications. Twelve of the bleeding episodes occurred at the puncture site, and 19 occurred at remote sites, accounting for six of the eight deaths in the series. Management errors were clearly identified in 27 of the 60 complications. The three following patterns of errors were recognized: (1) mismanagement of bleeding (12 instances), (2) wrong patient selection (nine instances), and (3) breach of the administration protocol (six instances). The group of 27 complications with underlying management errors included seven of the eight deaths in the present series. Efforts to prevent complications from thrombolytic therapy should concentrate on the specific patterns of management errors identified. This study indicates that low-dose intraarterial thrombolytic therapy is not a low-risk alternative to surgical intervention but should be viewed as a prelude or possible alternative to surgery in selected patients despite the risks involved.

Adolescent↗
PubMed1988

Effects of upper dorsal sympathectomy on esophageal motility in humans.

To evaluate the role of the sympathetic nervous system in modulating esophageal motility, esophageal manometry was performed on two groups of patients who underwent upper dorsal sympathectomy for relief of palmar hyperhydrosis. In six patients sympathectomy was done by the supraclavicular approach, with removal of T2 and T3 ganglia. Manometry was performed before the operation and three weeks after it. In seven other patients sympathectomy was done by the axillary approach, with removal of T2-T4 ganglia. Manometry in this group was performed 28.4 +/- 22.4 months after the operation. Fifteen individuals with an intact sympathetic system served as controls. Manometric parameters evaluated were esophageal contraction amplitude and duration and lower esophageal sphincter pressure. The difference between the results obtained in the pre- and postoperative periods in the first group was not statistically significant. The differences between the two patient groups and between the patient groups and the control group were not statistically significant either. We conclude that upper dorsal sympathectomy does not affect esophageal motility in man.

Adolescent↗
PubMed1987

Renovascular hypertension in spontaneous hypertensive rats: an experimental model of renal artery stenosis superimposed on essential hypertension.

Renovascular hypertension superimposed on essential hypertension, a condition encountered in the elderly, was studied. An experimental animal model consisting of a two-kidney one-clip Goldblatt preparation in the spontaneous hypertensive (SHR) rat, that would simulate this condition, was designed. A 0.25 mm silver clip was placed on the left renal artery of SHR male rats. The same procedure performed on WKY rats served as control. All experiments were performed on low, normal, and rich sodium diet. Systolic blood pressure (BP) was measured by tail-cuff method. Plasma renin concentration (PRC) was determined before and after clipping of the renal artery. Results were as follows: Mean systolic BP increased significantly in clipped rats fed with normal and rich sodium diets. SHR showed an increase from 144 +/- 3 (mean + s.e.m.) to 168 +/- 3 mmHg, and WKY rats showed an increase from 120 +/- 2 to 139 +/- 5 mmHg. There was a two- to threefold rise in PRC. A low-salt diet given prior to clipping prevented the appearance of renovascular hypertension despite a significant rise in PRC. We concluded that renal artery narrowing plays a significant role in the rise of BP in the basically essential type of hypertension.

Animals↗
PubMed1986

Partial purification and characterization of a procollagen C-proteinase from the culture medium of mouse fibroblasts.

A procollagen C-proteinase was purified about 100-fold from the medium of cultured mouse fibroblasts by a combination of ammonium sulfate precipitation, gel-filtration, and affinity chromatography on a column of Sepharose coupled to the carboxyl propeptide of type I procollagen. The purified enzyme did not exhibit other proteolytic activities, and it cleaved type I, II and III procollagens to produce the corresponding pN alpha chains and carboxyl propeptides as the only products. Amino acid sequencing of the first 14-18 residues at the N-terminus of the carboxyl propeptides generated by the enzyme from human pro alpha 1(I), pro alpha 2(I) and pro alpha 1(III) chains showed that the cleavage occurred at the physiological site, i.e. at the specific Ala-Asp bond in the pro alpha 1(I) and pro alpha 2(I) chains, and at the specific Gly-Asp bond in the pro alpha 1(III) chain. The pH optimum of the enzyme is 8.5 and its molecular weight as estimated by gel-filtration is about 125,000 daltons. The enzyme is inhibited by metal-chelators, various amines, dithiothreitol, N-ethylmaleimide and serum, but it is insensitive to pepstatin, leupeptin and serine proteases inhibitors. The enzyme differs from the C-proteinase described by Njieha et al. (Biochemistry 21:757-764, 1982), and the catheptic activities reported by Davidson et al. (Eur. J. Biochem 100:551-558, 1979) and Helseth and Veis (Proc. Natl. Acad. Sci. USA 81:3302-3306, 1984). The specificity of the enzyme is offered as evidence for a unique, C-proteinase, and its recovery from culture medium supports an extracellular location for procollagen processing.

Amino Acid Sequence↗
PubMed1986

Evidence for a protein that enhances the activity of type I procollagen C-proteinase.

Gel-filtration separated type I procollagen C-proteinase from a glycoprotein that enhanced the enzyme activity by approximately 4-fold. The enhancer was purified by affinity chromatography on a column of Sepharose coupled to the carboxyl propeptide of type I procollagen. Sodium-dodecyl-sulfate- polyacrylamide gel electrophoresis of the affinity-purified enhancer revealed two active major protein bands with molecular weights of 36 and 34 kdal. Both proteins were glycosylated, as shown by binding to concanavalin-A. The enhancer is extremely heat stable (100 degrees C, 15 min) but its activity is totally abolished by treatment with trypsin or bacterial elastase. The enhancer does not alter the digestion intermediates or final products of the enzymatic reaction but it changes the kinetic properties of the reaction, increasing the apparent Km and Vmax values 16- and 20-fold, respectively. It is suggested that the enhancer might play a regulatory role in procollagen processing.

Animals↗
PubMed1986

Cardiovascular changes after bilateral upper dorsal sympathectomy. Short- and long-term effects.

The effect of bilateral upper dorsal sympathectomy (UDS) on cardiac function was investigated in two groups of young healthy patients who underwent bilateral excision of T2 and T3 ganglia for palmar hyperhidrosis. In ten patients echocardiography of left ventricular function (LVF) was performed before operation and 2 weeks after operation. Electrocardiograms (ECG) were done before operation, during operation immediately after sectioning each sympathetic chain, and at 2 weeks after operation. The mean pulse rate decreased significantly in patients after they underwent bilateral UDS. There were no clinical arrhythmias or changes in LVF in any patient. Submaximal exercise testing and ECG tracings done at rest and after effort were obtained for 29 patients before undergoing bilateral UDS, 30 days after operation, and 1-3 more times within a 2-year postoperative period. Pulse rates taken at rest and after effort were significantly lower than those taken after operation, and the blood pressure response to exercise was blunted. ECG tracings showed a significant change in the electrical frontal plane axis and shortening of the QTc interval. These changes were evident 30 days after operation and persisted for 2 years. In conclusion, bilateral UDS has no overt arrhythmogenic effect in the young, healthy heart and its beta-blocker-like effect persists for at least 2 years.

Adolescent↗
PubMed1986

Percutaneous transluminal angioplasty. A suggested method for analysis of clinical, arteriographic, and hemodynamic factors affecting the results of treatment.

Sixty-nine percutaneous transluminal angioplasties (PTAs) were performed in the iliac and the femoral arteries of 54 patients. The main factors that might affect the results were reviewed: associated diseases, severity of ischemic symptoms, location and type of lesions (stenosis or occlusion and their length), and presence of disease distal to the site dilated. The vascular status of the patients in our series was more severe than in most others. Improvement at follow-up (average 15 months) was maintained in 74% of 66 radiographically successful PTAs. Poor runoff was the only factor found to affect the outcome deleteriously. Intra-arterial pressure measurements performed during the procedure and vascular laboratory studies were most valuable in assessing immediate and long-term results. Wide variations in results of PTA published in the literature are due to differences in methods of selection, evaluation, and reporting. A plea is made for future presentations of PTA series in an analyzable and comparable way, including and correlating all relevant variables as in the model suggested by the present study.

Adult↗
PubMed1985

Left renal vein division in abdominal aortic aneurysm operations. Effect on renal function.

We examined the effect of left renal vein (LRV) division during abdominal aortic aneurysm operations on renal function during the recovery period. Fifteen patients with LRV division were compared with 26 patients in whom the LRV was not ligated. These two groups of patients did not differ significantly in any of their preoperative characteristics, operative management, or postoperative complications. Preoperative, highest postoperative, and predischarge levels of plasma urea and creatinine, as well as urinary sediment, were compared in both groups. Left renal vein division could not be implicated as a cause of renal function deterioration and was found to be a safe, useful adjunct to abdominal aortic aneurysm surgery.

Adult↗