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Biomedical subjects

S L Houser

Publications and source records attributed to S L Houser.

27 records · Page 2Linked to original sources
PubMed1984

Should the greater saphenous vein be preserved in patients requiring arterial outflow reconstruction in the lower extremity?

Two patient groups were studied to determine the need to preserve the greater saphenous vein during femoral outflow reconstruction for later aortocoronary bypass procedures. First, 74 patients were followed to the time of death or to a minimum of 5 years after femoral outflow reconstruction was performed. Only four patients (5.4%) underwent subsequent aortocoronary bypass. The previous outflow procedures had no adverse effect on the quality of aortocoronary conduit. Risk factors were analyzed to help predict the incidence of later coronary revascularization after femoral outflow reconstruction was performed. The second group that was analyzed included 500 nearly consecutive patients who underwent aortocoronary bypass. In 15 of these patients (3%), there was inadequate saphenous vein for conduit use. In no case was the inadequacy of saphenous vein due to its previous use as outflow conduit in the leg. Only seven patients (1.4%) had had an outflow reconstruction prior to aortocoronary bypass. In conclusion, continued use of adequate greater saphenous vein as femoral outflow conduit is justified despite the high incidence of coronary artery disease in these patients.

Adult↗
PubMedDate not supplied

Long-term acceptance of porcine pulmonary allografts without chronic rejection.

OBJECTIVES: The mechanisms and treatment of chronic rejection in pulmonary allotransplantation remain elusive. Using a strategy to induce tolerance across strong allogeneic barriers, we have employed a brief, intensive course of immunosuppression to determine whether the induction of donor-specific hyporesponsiveness would prevent allograft rejection in a preclinical model of lung transplantation using MHC-inbred miniature swine. METHODS: Orthotopic left lung allografts were performed using MHC class I-disparate donors. The recipients received a 12-day postoperative course of cyclosporine (n = 6) or a 12-day postoperative course of high-dose tacrolimus (n = 3) as their only immunosuppression. Control animals received no immunosuppression (n = 3). RESULTS: Cyclosporine-treated recipients exhibited graft survival ranging from 67 to >605 days. All six animals developed acute cellular rejection between postoperative days (PODs) 27 and 108. Two animals lost their grafts on PODs 67 and 69, before developing obliterative bronchiolitis (OB). The other four recipients developed OB between PODs 119 and 238. In contrast, all tacrolimus-treated recipients maintained their grafts long term, without developing chronic rejection (>339, >308, and >231). These recipients also exhibited donor-specific hyporesponsiveness in assays of cell-mediated lymphocytotoxity. All untreated control animals lost their grafts to acute rejection by POD 11. CONCLUSIONS: This study demonstrates the ability of a brief course of high-dose tacrolimus to induce long-term graft acceptance with donor-specific hyporesponsiveness in a class I-disparate preclinical lung transplant model.

Animals↗
PubMedDate not supplied

Potential of aspirin to inhibit thrombotic microangiopathy in alpha1,3-galactosyltransferase gene-knockout pig hearts after transplantation in baboons.

Hearts from alpha1,3-Galactosyltransferase gene-knockout (GaIT-KO) pigs were transplanted heterotopically into 8 baboons that received an anti-CD154 monoclonal antibody (mAb)-based immunosuppressive regimen and heparin. Three baboons died or were euthanized with beating grafts on 16, 23, and 56 days, respectively, and the remaining 5 grafts functioned for 59-179 days. Hyperacute rejection did not occur, and classical features of acute humoral xenograft or acute cellular rejection were rare. However, thrombotic microangiopathy (TM) developed in all cases; its onset was delayed in 2 baboons that received aspirin. Function of a pig organ in a baboon for a period approaching 6 months has not been reported previously and lends encouragement that the barriers to xenotransplantation will be overcome, but TM requires investigation.

Animals↗
PubMedDate not supplied

Serum lipids and arterial plaque load are altered independently with high-dose progesterone in hypercholesterolemic male rabbits.

Antiatherogenic effects of sex steroids in premenopausal women are not well defined. Therefore, we employed an established rabbit model for atherosclerosis to study the effects of exogenous estrogen and a progesterone analogue (P) on serum lipids and aortic plaque load. Serum cholesterol (C) and triglyceride (T) levels and atherosclerotic plaque loads were compared in 5 groups of male New Zealand White rabbits fed a 12-week, C-rich diet: 1 control group (CG) and 4 groups treated with estriol (E), haloperidol (H), low-dose 17-hydroxyprogesterone (LDP), or high-dose 17-hydroxyprogesterone (HDP). Serum P was measured in the LDP and HDP groups. Serial histologic sections (15 each of 27 ascending aortas) were studied by light microscopy and computerized morphometric analysis. Plaque load is defined as the ratio of intimal area to medial area (I/M). Exogenous E (p<0.001), H (P = 0. 02), LDP and HDP (P<0.001, each) were found to be significantly associated with less aortic plaque load than controls. In a multivariate analysis, after controlling for the differences in serum C and T levels, HDP (p = 0.014) was found to be associated with less aortic plaque load than controls, and this association approached statistical significance in the E (p = 0.052) and H (p = 0.069) groups. These data suggest that the mechanism(s) involved with the antiatherogenic effect of HDP in this animal model is, or are, independent of an alteration in serum lipids.

17-alpha-Hydroxyprogesterone↗
PubMedDate not supplied

Valvular heart disease in patients with hypocomplementemic urticarial vasculitis syndrome associated with Jaccoud's arthropathy.

BACKGROUND: Since 1973, more than 75 patients with hypocomplementemic urticarial vasculitis syndrome (HUVS) were reported, but valvular heart disease does not seem to have been noted in these patients. Since 1993, however, five patients with HUVS accompanied by Jaccoud's arthropathy (JA) were found to have serious valvular heart disease. METHODS: To characterize the cardiac valvulopathy of the third patient with HUVS/JA to have undergone valve replacement, this study included the use of routine and special tissue stains, as well as immunohistochemical staining. We compared gross and histologic findings of this patient's valve to those of two other patients with this complex syndrome who underwent valve replacement. Pathologic findings of these latter two patients were described in separate earlier reports. RESULTS: Histologic examination of the resected valves in all three patients showed an acute necrotizing endocarditis and fibrin deposition on the surface of valve leaflets. Beneath the surfaces of the leaflets, there was evidence of chronic inflammation, consisting of lymphocytes and histiocytes. A fibrocalcific degenerative change was also present in all three valves. Positive staining for IgG, IgA, IgM, and light-chain determinant-bearing proteins was detected primarily at the valve surface in special studies of the aortic valve of the patient described in the current report. CONCLUSION: Patients with HUVS and associated JA should be evaluated for the presence of valvular heart disease. The latter is probably a nonrheumatic, inflammatory, and degenerative process, mediated by immune complex, as well as cellular immune mechanisms.

Antigen-Antibody Complex↗