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J H Rapp

Publications and source records attributed to J H Rapp.

68 records · Page 4Linked to original sources
PubMed1987

Hypercholesterolemia and early restenosis after carotid endarterectomy.

Cellular proliferation in response to endothelial injury has been examined extensively in experimental animals. Under certain conditions (e.g., hypercholesterolemia and hypertension), this response can be exaggerated and develop into lesions that resemble early atherosclerosis. The injury caused by endarterectomy in human beings and the repair of the arterial wall that ensues may be analogous to the animal models. Presumably, those patients with an exaggerated proliferative response manifest myointimal hyperplasia and recurrent stenosis. To determine potential causes of recurrent stenosis after carotid endarterectomy, we studied 31 patients with early restenosis (group I), 35 patients with later restenosis (group II), and compared them with a control group of 100 consecutive patients who underwent uncomplicated carotid endarterectomy (group III). The known risk factors for atherosclerosis were analyzed. There was no significant difference in the male-to-female ratio, number of cigarettes smoked, or incidence of diabetes mellitus. However, the serum cholesterol level for group I was 282 +/- 57 mg/dl (p less than 0.001 versus controls) while the serum cholesterol level in group II was not significantly elevated over that of the control group. Both groups I and II had a higher incidence of hypertension (p less than 0.005 for both versus controls). There were no differences in the severity of hypertension. The data suggest that hypercholesterolemia has a strong association with early restenosis after carotid endarterectomy but not with late recurrent disease and that hypertension, even when treated, may be associated with both early and late recurrent stenosis.

Adult↗
PubMed1986

Ischemia of the upper extremity: significance of proximal arterial disease.

Thirty-four patients had upper extremity ischemia due to proximal arterial disease, including subclavian compression at the thoracic outlet, innominate or subclavian atherosclerosis, and other causes. Nineteen lesions caused distal embolization. Although successful arterial reconstructions were performed in all but one patient, there were five major amputations. Four were associated with a delay in diagnosis, which allowed the formation of repeated distal emboli. Since overlooked proximal brachiocephalic arterial lesions can produce devastating consequences, we believe these vessels should be examined in all cases of hand and arm ischemia.

Adolescent↗
PubMed1986

Durability of endarterectomy and antegrade grafts in the treatment of chronic visceral ischemia.

Several techniques have been used to revascularize the visceral circulation. Although initially successful, these repairs often have a significant rate of late occlusion. To determine the durability of transaortic endarterectomy (TEA) and antegrade aortovisceral grafting, we reviewed the last 67 consecutive patients operated on at the University of California, San Francisco for chronic visceral ischemia. The patients were principally middle-aged (mean, 59 years) women (76%) with atherosclerotic disease involving at least two major visceral arteries. Forty-seven patients underwent TEA; 22 patients had associated renal endarterectomy, and 15 patients had simultaneous aortic reconstructions. Twenty patients had an aortovisceral antegrade bypass placed as their only reconstruction. Two of these had concomitant aortic reconstructions. There were five perioperative deaths. Of the 62 patients available for follow-up, 60 patients who had a total of 111 major visceral branch repairs have been followed up for 6 months to 14 years (mean, 4.4 years). Four patients (7%) have had recurrent visceral ischemia. Two patients had recurrent symptoms and have been asymptomatic for nearly 5 and 6 years, respectively, after successful reoperations. Two patients had intestinal infarction and died as a result. Thirty-four patients have had follow-up aortography that showed 58 widely patent reconstructions, two asymptomatic single-vessel stenoses, and one asymptomatic occlusion. TEA and antegrade visceral bypass provided long-term relief of symptoms and prevented visceral gangrene in 56 of 60 patients (93%). The prolonged patency of these reconstructions is attributed to the following: They originate from undiseased or endarterectomized aorta, they provide optimal, nonturbulent flow, and they avoid the inherent technical pitfalls of retrograde grafting.

Adult↗
PubMed1986

Composition and metabolism of symptomatic distal aortic plaque.

This study examines the composition of advanced human atherosclerotic lesions removed by endarterectomy and compares the collagen synthesis in the lesion with that of the intima-media layer of uninvolved vessel wall. The most striking feature of the lesions is an enormous accumulation of calcium that was raised more than tenfold, from a level of about 3% of dry tissue weight in the normal tissue to values approaching 50% in the pathologic specimens. The composition of the organic matrix was also altered. Elastin and glycosaminoglycan content decreased, whereas collagen content more than doubled, thus becoming the major component of the organic matrix. The cholesterol content increased severalfold above normal but even then accounted for less than 10% of the organic matrix. The lesion specimens synthesized collagen in vitro at a greater rate than normal tissue. The endarterectomy specimens with the highest calcium content exhibited the highest rate of collagen synthesis.

Adult↗
PubMed1983

Lipids of human atherosclerotic plaques and xanthomas: clues to the mechanism of plaque progression.

While the content of fatty streaks and fibrous plaques has been extensively studied in autopsied specimens, little is known about the lipid composition of advanced human atherosclerotic plaques requiring surgical removal. We have analyzed free cholesterol, cholesteryl ester, and the cholesteryl ester fatty acid content in 19 carotid and 7 femoral obliterative plaques obtained at endarterectomy. These were compared with values from each subject's plasma and from xanthomas removed from eight patients. The total cholesterol content was 75.1 mg/g dry weight for carotid plaques, 56.0 mg/g for femoral plaques, and 106.8 mg/g for xanthomas. The free cholesterol content was 56.6% and 50.4% of the total cholesterol for carotid and femoral plaques, respectively, while the free cholesterol of xanthomas was only 25.5%. The fatty acids of cholesteryl esters were analyzed in an attempt to identify the site of their esterification, i.e., within plasma or within plaque. This can be determined using the ratio of linoleic acid (18:2) to oleic acid (18:1) in the cholesteryl ester. The ratios were 0.36 for xanthoma, 1.62 for carotid plaque, 1.73 for femoral plaque, and 2.51 in plasma. These data emphasize two chemical changes occurring with evolution of the atherosclerotic process: 1) The cholesteryl ester fatty acid composition of the plaque becomes increasingly similar to that of plasma, and 2) there is a continuing increase in the percentage of free cholesterol. These alterations reflect a decreased metabolic efficiency within atherosclerotic lesions and may initiate events that enhance plaque progression.

Arteriosclerosis↗
PubMed1981

Colestipol plus nicotinic acid in treatment of heterozygous familial hypercholesterolaemia.

Thriteen patients with heterozygous familial hypercholesterolaemia (FH) were sequentially treated with: a low-cholesterol, fat-restricted diet; diet and colestipol; and diet and colestipol and nicotinic acid. Concentrations of plasma cholesterol decreased from 415 +/- 69 mg/dl on diet alone to 327 +/- 54 mg/dl on colestipol and fell to 246 +/- 49 mg/dl on the combined drug regimen. Plasma concentrations of LDL cholesterol declined 24% on colestipol; the subsequent addition of nicotinic acid resulted in a further 31% fall so that values on the combined drug regimen were 47% below those seen on diet alone. HDL cholesterol levels were similar on both the diet (40 mg/dl) and colestipol (43 mg/dl) treatment periods but increased to 53 mg/dl on the combined drug regimen. Treatment resulted in significant decreases in the LDL:HDL ratio which fell from 8.4 on diet to 3.3 on the colestipol plus nicotinic acid regimen. In most patients with heterozygous FH, combined use of a bile acid sequestrant and nicotinic acid affords the opportunity to maintain a normal lipid profile. Prolonged use of this regimen may reduce the incidence of premature coronary atherosclerosis which naturally occurs in these patients.

Adult↗
PubMedDate not supplied

Testosterone regulates metabolism of plasma chylomicrons in rats.

Previously we demonstrated a marked sex difference in the metabolism of chylomicrons in adult rats. In males, radiolabeled chylomicrons displayed a longer dwell time on endothelial surfaces, which resulted in a decreased chylomicron uptake by the liver. The increased rate of chylomicron metabolism in females was associated with increased postheparin lipoprotein lipase activity. In the present study, we have investigated the effects of physiological doses of sex steroid hormones on the metabolism of chylomicrons and postheparin lipoprotein lipase activity. No sex differences were found in prepubertal animals. We also found no difference in chylomicron metabolism in control female, castrated female, estrogen-treated female, castrated male, and estrogen-treated male rats. However, control male, testosterone-treated male, and testosterone-treated female rats showed increased endothelial binding of chylomicrons and decreased chylomicron uptake by the liver. Postheparin lipoprotein lipase activity also was decreased by testosterone administration. In parallel with the alterations in chylomicron metabolism, serum high density lipoprotein levels in male rats decreased with testosterone administration. These results indicate that the differences in chylomicron metabolism, postheparin lipoprotein lipase activities, and serum high density lipoprotein levels observed between male and female rats are due to testosterone.

Animals↗
PubMedDate not supplied

Dietary eicosapentaenoic acid and docosahexaenoic acid from fish oil. Their incorporation into advanced human atherosclerotic plaques.

The incorporation of fatty acids from dietary fish oil was measured in obstructive atherosclerotic plaques removed from 11 patients fed fish oil, rich in omega-3 fatty acids, for 6-120 days before a planned arterial endarterectomy. The fatty acids of plasma and atheroma were analyzed with special reference to docosahexaenoic acid (DHA, 22:6) and eicosapentaenoic acid (EPA, 20:5), the principal omega-3 fatty acids of fish oil. The omega-3 fatty acid content increased greatly in plasma from 0.9% of fatty acids to 14.8% in cholesteryl esters, from 3.8% to 22.1% in phospholipids, and from 1.3% to 21.9% in triglycerides. The omega-3 fatty acid content of the atherosclerotic plaques was also greater when compared with that of plaques removed from 18 non-fish oil-fed controls. The omega-3 fatty acid in cholesteryl esters of the plaques was 4.9% in the experimental group versus 1.4% in control plaque, in phospholipids it was 8.8% versus 1.8%, and in triglycerides it was 4.7% versus 0.7% (p less than 0.001 for each lipid class). The two major omega-3 fatty acids (DHA and EPA) behaved differently. Compared with their respective plasma levels, relatively more DHA than EPA was deposited into the plaques. Whereas the increase of omega-3 fatty acids in plasma reached a plateau 3 weeks after initiation of fish oil feeding, a linear increase in plaque omega-3 fatty acids continued with time. As a result of the changes in fatty acid composition, the lipid classes of both plasma and plaque had a higher unsaturation index in the fish oil-fed group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Connective tissue proteinases and inhibitors in abdominal aortic aneurysms. Involvement of the vasa vasorum in the pathogenesis of aortic aneurysms.

Recent studies have shown that increases in proteolytic activity are associated with abdominal aortic aneurysms (AAAs). We have studied samples of the dilated aortic wall, taken during corrective surgery for AAAs, in terms of the number, type, and tissue location of connective tissue proteinases and their inhibitors. Five distinct caseinolytic serine proteinases and six gelatinolytic metalloproteinases were resolved by molecular weight by use of sodium dodecyl sulfate-substrate gel electrophoresis. Isoforms of the Mr 92,000 neutrophil gelatinase were identified by immunoprecipitation of biosynthetically labeled organ culture media. About 50% of the total radiolabeled protein secreted by AAA organ cultures was identified as the Mr 30,000 glycoprotein, tissue inhibitor of metalloproteinase (TIMP), by immunoprecipitation. Both TIMP and gelatinase were localized to the vasa vasorum by immunoperoxidase staining. However, interstitial collagenase could not be detected by any method. These results suggest the involvement of the vasa vasorum in the maintenance and possibly the genesis of AAAs.

Aorta, Abdominal↗
PubMedDate not supplied

Assessment of carotid artery stenosis by MR angiography: comparison with x-ray angiography and color-coded Doppler ultrasound.

PURPOSE: To compare magnetic resonance angiography (MRA) with duplex Doppler ultrasound (US) and x-ray angiography (XRA) in the evaluation of the carotid bifurcation. METHODS: The carotid arteries of 61 patients were studied using MRA, US, or XRA; 31 of the patients underwent all three examinations. MRA included both 2D and 3D time-of-flight sequences. Internal and external carotid artery origins were graded normal, mild, moderate, severe, or critical stenosis, or complete occlusion by each of the three studies. RESULTS: Spearman rank correlations of both internal and external carotid artery grades were 0.85 (MRA and XRA), 0.69 (MRA and US), and 0.73 (XRA and US). For internal carotid artery origins only, the correlations were 0.94 (MRA and XRA), 0.85 (MRA and US), and 0.82 (XRA and US). Of discrepancies in internal carotid artery interpretation greater than one grade, seven resulted from US error, three from MRA error, and one from XRA error. A 2-cm partially thrombosed aneurysm detected by US and MRA was missed by XRA. Of 16 possible ulcers on XRA, 11 were noted by MRA, none by US. CONCLUSIONS: MRA and XRA are similar in assessment of carotid bifurcation stenosis. MRA, like US, permits direct visualization of plaque. This preliminary study suggests that MRA may be used to clarify equivocal findings of US, or replace XRA in presurgical planning.

Aged↗