Biochemical metabolism of young plants of Ucuúba (Virola surinamensis) in the presence of cadmium.

Virola surinamensis is a forest species widely distributed in the estuaries of the Amazon. These ecosystems are susceptible to contamination by Cadmium (Cd), indicating that the plant has strategies for tolerating this metal. The aim of this study was to assess the nitrogen and carbon metabolism of young plants of Ucuúba (Virola surinamensis) in the presence of cadmium with the perspective of the phytoremediation of contaminated environments. The used experimental design was a completely randomized design with five Cd concentrations (0, 15, 30, 45, and 60 mg L- 1), for 60 days. In general, Cd did not affect nitrate concentration in the root but had a positive effect on leaves. The reduction of nitrate reductase (NR) in plants exposed to Cd was followed by a decrease in ammonia, total soluble amino acids (TSA), and total soluble proteins (TSP). Cd promoted an increase in the concentration of total soluble carbohydrates (TSC), proline, sucrose, and reducing sugars in the plants. The increase in TSC, sucrose and proline, suggests a metabolic regulatory mechanism of V. surinamensis against Cd stress.

Retrospective clinical analysis of stented vs. stentless porcine aortic bioprostheses.

OBJECTIVE: The study was designed to compare hemodynamic performance, structural failure and survival of patients undergoing aortic valve replacement (AVR) with a composite aortic stented or stentless porcine bioprosthesis. METHODS: From January 1990 to June 1999, the clinical data of 725 patients undergoing AVR with stented porcine aortic bioprosthesis were reviewed. We defined two groups of patients with similar clinical characteristics: 202 patients receiving aortic stented and 205 patients stentless valves. The two patients groups were similar in age, sex, valve lesion, valve size, preoperative New York Heart Association (NYHA) class status and follow-up. RESULTS: The number of patients available for follow-up, excluding hospital and late mortality, reoperations and patients lost to follow-up, was 157 for the stented and 175 for the stentless group. There was a higher incidence of rheumatic heart disease in the stented (59%) vs. stentless group (44%), (P=0.003). Fewer patients had prior aortic bioprosthetic dysfunction in the stented (7.6%) compared to the stentless group (25%) (P<0.001). The mean intensive care unit stay, hospital mortality and late mortality were similar (P, NS). The total complication rate was higher in the stented (12%) than the stentless (3.4%)(P=0.005). Valve related death was higher in the stented (2.5%) than the stentless (0%) (P=0. 049). Postoperatively, the aortic effective orifice area (AEOA) was larger (P<0.001) and the transvalvular peak and mean gradients were lower in the stentless group (P<0.001). The leaflet tissue degeneration analysis was 8.0% in patients at risk for stented and 0. 6% for stentless (P=0.001). Actuarial analysis disclosed no statistical difference in patient survival between groups (P=0.18). Reoperations were less frequent in the stentless group (P=0.010). CONCLUSIONS: Hemodynamic benefits in the stentless group were evident and expressed by larger AEOA, lower gradients, better left ventricular remodeling with significant decrease of the left ventricular mass. Lower complication rates, lower reoperation rates, less leaflet tissue degeneration, and lower valve related mortality rates were seen in the stentless group. A controlled clinical comparison trial with longer follow-up will be required to confirm these clinical and hemodynamic benefits.

The use of bovine pericardium for pulmonary valve reconstruction or conduit replacement: long-term clinical follow up.

BACKGROUND AND AIMS OF THE STUDY: This study aimed to determine the clinical performance of bovine pericardial aldehyde-treated material alone or in combination with aortic leaflets of porcine origin. These were the porcine aortic stentless pulmonary valved bovine pericardial conduit (PSPVC), and porcine aortic monocusp attached to pericardial patch (PAMC), used to correct right-sided heart lesions. METHODS: Between November 1985 and October 1995, 33 patients underwent corrective congenital surgery with PSPVC. Mean patient age was 5.7+/-4.3 years (range: 15 days to 18 years). Pulmonary atresia with ventricular septal defect (VSD) was the most frequent disease (16/33, 48%). For PAMC, 45 patients with various congenital heart malformations underwent implantation between June 1989 and April 1996. Mean patient age was 4.8+/-4.7 years (range: 2 weeks to 18 years). RESULTS: With PSPVC, hospital mortality rate was 18.2% and related to poor preoperative clinical condition in six cases. Four patients were lost to follow up; 23 (85%) were followed for 3 months to 10 years (mean 4.8+/-3.0 years). Distal anastomotic scarring in four patients was probably due to retraction of the pericardial tissue. With PAMC, hospital mortality rate was 11% and related to patients' preoperative clinical condition. Three patients were lost to follow up; 37 survivors have been followed for 6 to 88 months (mean 38.5+/-19.0 months). There were no late deaths. Two patients underwent reoperation; intra-operative observation showed well-preserved monocusps with no signs of tissue degeneration. The remaining 35 patients remain asymptomatic by clinical examination and Doppler echocardiography. The monocusps remained mobile in every case. CONCLUSION: PSPVCs have shown excellent performance and durability in young patients with a low mean age (5 years). The monocusp graft has remained functional with good leaflet motion for up to seven years.

Immune complex deposition in the choroid plexus of patients with acquired immunodeficiency syndrome.

We identified immune complex deposits in the choroid plexus of approximately 75% of patients with acquired immunodeficiency syndrome (AIDS) who had either normal brains or human immunodeficiency virus encephalitis. Since circulating immune complexes are common in AIDS patients, and since local choroid plexus pathology usually was absent, their likely origin is from the bloodstream. Choroid plexus deposits of immune complexes have been implicated in altering the function of this structure or in enhancing its vulnerability to infection. Therefore, immune complex deposition in the choroid plexus of AIDS patients may be responsible for some of the common alterations in the cerebrospinal fluid and for the frequency of opportunistic infections in this region.

Histochemical localization of enzyme activity in the kidneys of male marmosets (Callithrix jacchus and Callithrix penicillata).

The distribution of several hydrolases and oxidoreductases was studied in the renal parenchyma of adult male marmosets (Callithrix jacchus and Callithrix penicillata). The oxidative enzymes showed a high reactivity in the proximal and distal tubules, whereas the hydrolases reacted strongly in the proximal tubules but only weakly or not at all in the thick limb of Henle's loop, distal tubules and collecting ducts. The NAD-dependent enzymes (except alpha-GPDH) showed a stronger reactivity in the proximal tubules, while the NADP-dependent ones were more reactive in the thick limb of Henle's loop and distal convoluted tubules. Two groups of interstitial cells were found in the medulla. A first group inside the outer medulla, showing cells rich in acid phosphatase and nonspecific esterases and a second group, close to the papilla, reactive to a certain number of oxidative enzymes. A different reactivity in cells of the distal convoluted tubules, thick limb of Henle's loops and collecting ducts (dark cells) was seen in the case of some enzymes like nonspecific esterase, alpha-GPDH and SDH.