Last twenty-years activity of cardiovascular tissue banking in Barcelona.

The Barcelona Tissue Bank was established from the merge of two previous multi-tissue banks. Potential donors are screened by Donor Center staff and multi-tissue retrieval is performed by specialized own teams. Tissue processing and preservation is performed in clean room facilities by specialised personnel. After quality control of both donor and all tissues results, the heart valves and vascular segments are stored until medical request. The aim of this report is to present the cardiovascular tissue activity and retrospectively evaluate the outcomes of the changes performed in last 20 years. Cardiovascular tissue from 4088 donors was received, specifically 3115 hearts and 2095 vascular segments were processed and evaluated. A total of 48% of the aortic valves, 68% of the pulmonary valves and 75% of the vascular segments were suitable for transplant. The main reason for discarding tissue was macroscopic morphology followed by microbiological results, for both valves and arteries. Altogether, 4360 tissues were distributed for transplantation: 2032 (47%) vascular segments, 1545 (35%) pulmonary valves and 781 (18%) aortic valves. The most common indication for aortic valve surgery was the treatment of endocarditis, while for pulmonary valves, it was congenital malformation reconstruction. Vascular segments were mainly used for reconstruction after ischemia. During this period, a number of changes were made with the goal of enhancing tissue quality, safety and efficacy. These improvements were achieved through the use of a new antibiotic cocktail, increasing of donor age criteria and changing the microbiological control strategy.

Sludge reduction by uncoupling metabolism: SBR tests with para-nitrophenol and a commercial uncoupler.

Nowadays cost reduction is a very important issue in wastewater treatment plants. One way, is to minimize the sludge production. Microorganisms break down the organic matter into inorganic compounds through catabolism. Uncoupling metabolism is a method which promote catabolism reactions instead of anabolism ones, where adenosine triphosphate synthesis is inhibited. In this work, the influence of the addition of para-nitrophenol and a commercial reagent to a sequencing batch reactor (SBR) on sludge production and process performance has been analyzed. Three laboratory SBRs were operated in parallel to compare the effect of the addition of both reagents with a control reactor. SBRs were fed with synthetic wastewater and were operated with the same conditions. Results showed that sludge production was slightly reduced for the tested para-nitrophenol concentrations (20 and 25 mg/L) and for a LODOred dose of 1 mL/day. Biological process performance was not influenced and high COD removals were achieved.

Comparison between mixed liquors of two side-stream membrane bioreactors treating wastewaters from waste management plants with high and low solids anaerobic digestion.

In the last years, biological treatment plants for the previously separated organic fraction from municipal solid wastes (OFMSW) have gained importance. In these processes a liquid effluent (liquid fraction from the digestate and leachate from composting piles), which has to be treated previously to its discharge, is produced. In this paper, the characteristics of the mixed liquor from two full-scale membrane bioreactors treating the effluents of two OFMSW treatment plants have been evaluated in view to study their influence on membrane fouling in terms of filterability. For that, the mixed liquor samples have been ultrafiltrated in an UF laboratory plant. Besides, the effect of the influent characteristics to MBRs and the values of the chemical and physical parameters of the mixed liquors on the filterability have been studied. Results showed that the filterability of the mixed liquor was strongly influenced by the soluble microbial products in the mixed liquors and the influent characteristics to MBR. Permeate flux of MBR mixed liquor treating the most polluted wastewater was considerable the lowest (around 20 L/m(2) h for some samples), what was explained by viscosity and soluble microbial products concentration higher than those measured in other MBR mixed liquor.

Performance of ceramic ultrafiltration membranes and fouling behavior of a dye-polysaccharide binary system.

Ultrafiltration membrane processes have become an established technology in the treatment and reuse of secondary effluents. Nevertheless, membrane fouling arises as a major obstacle in the efficient operation of these systems. In the current study, the performance of tubular ultrafiltration ceramic membranes was evaluated according to the roles exerted by membrane pore size, transmembrane pressure and feed concentration on a binary foulant system simulating textile wastewater. For that purpose, carboxymethyl cellulose sodium salt (CMC) and an azo dye were used as colloidal and organic foulants, respectively. Results showed that a larger pore size enabled more solutes to get adsorbed into the pores, producing a sharp permeate flux decline attributed to the rapid pore blockage. Besides, an increase in CMC concentration enhanced severe fouling in the case of the tighter membrane. Concerning separation efficiency, organic matter was almost completely removed with removal efficiency above 98.5%. Regarding the dye, 93% of rejection was achieved. Comparable removal efficiencies were attributed to the dynamic membrane formed by the cake layer, which governed process performance in terms of rejection and selectivity. As a result, none of the evaluated parameters showed significant influence on separation efficiency, supporting the significant role of cake layer on filtration process.

Hyaline cartilage surface study with an environmental scanning electron microscope. An experimental study.

To obtain images of the articular surface of fresh osteochondral grafts using an environmental scanning electron microscope (ESEM). To evaluate and compare the main morphological aspects of the chondral surface of the fresh grafts. To develop a validated classification system on the basis of the images obtained via the ESEM. The study was based on osteochondral fragments from the internal condyle of the knee joint of New Zealand rabbits, corresponding to fresh chondral surface. One hundred images were obtained via the ESEM and these were classified by two observers according to a category system. The Kappa index and the corresponding confidence interval (CI) were calculated. Of the samples analysed, 62-72% had an even surface. Among the samples with an uneven surface 17-22% had a hillocky appearance and 12-16% a knobbly appearance. As regards splits, these were not observed in 92-95% of the surfaces; 4-7% showed superficial splits and only 1% deep splits. In 78-82% of cases no lacunae in the surface were observed, while 17-20% showed filled lacunae and only 1-2% presented empty lacunae. The study demonstrates that the ESEM is useful for obtaining and classifying images of osteochondral grafts.

Cryopreservation alters antigenicity of allografts in a porcine model of transplant vasculopathy.

UNLABELLED: The need for arterial grafts in coronary surgery to complement autologous vessels has generated interest in cryopreservation of small diameter allografts. We evaluated functional and histologic changes occurring in cryopreserved allografts 3 months after porcine femoral artery transplants. METHODS: Twenty recipient and 15 donor pigs included a control group of 16 fresh and 12 cryopreserved nonimplant arteries were used. Fresh (n=5) and cryopreserved (n=5) autografts were implanted to assess cryopreservation effects in the absence of rejection. Fresh allografts with or without treatment with cyclosporine (CsA) (n=6 of 8) and cryopreserved allografts with or without treatment with CsA (n=6 of 10) were performed to study the antigenicity of cryopreserved allografts. Arteries were stained with hematoxylin and eosin, Masson's trichrome, and orcein for morphometric analyses and immunostained to identify endothelial cells, smooth muscle cells, T lymphocytes, and macrophages. RESULTS: Among nonimplant arteries, cryopreservation reduced alpha-actin expression and increased the luminal area. All implanted autografts were patent. Cryopreserved autografts showed reduced alpha-actin expression and developed intimal hyperplasia compared to fresh autografts. Treatment with CsA improved the patency of fresh allografts from 0% to 83% (P <.01) and of cryopreserved allografts from 40% to 100% (P <.05). Cryopreserved allografts showed substantial intimal hyperplasia, and fresh allografts had more T lymphocyte infiltration in the intimal layer with aneurysmal dilatation. CONCLUSIONS: Cryopreservation reduces the deposition of inflammatory cells and prevents the thrombosis or aneurysmal lesions observed in fresh allografts. Therefore, cryopreservation modifies the antigenicity of vascular allografts.

Drug-induced otoxicity: current status.

We carried out a review of the literature published over the last 10 years on drug-induced ototoxicity by means of a Medline search using the terms 'clinical ototoxicity' for the period January 1990 to September 2000 and found 414 published articles. In order to summarize the content of these articles, we asked ourselves a series of nine questions and answered them based on the most widely-held views and those we considered of greatest interest in the articles reviewed. The questions asked were: what are the most commonly used ototoxic drugs? what is the site of action of ototoxic drugs? what is the importance of the dose and dosing interval? does age influence ototoxicity? are all humans equally prone to the ototoxic effects of drugs? are there substances that are protective against ototoxicity? can hearing loss be monitored? should hearing loss be attributed to ototoxic drugs in all cases? and is ototoxicity in animals the same as in humans?

[Bioartificial liver support for acute liver failure. First case treated in Spain]. / Soporte hepático bioartificial en la insuficiencia hepática aguda grave. Primer caso tratado en España.

BACKGROUND: Research aimed at developing artificial liver support systems has experienced a notable increase in the last decade. Hybrid systems including bioreactors containing hepatocytes which are perfused by liver failure patients blood or plasma have been deviced for the first time. The purpose of such a strategy is to substitute, at least in part, the impaired hepatic function thus improving the prognosis of patients with severe acute or chronic liver diseases. CASE REPORT: In the present paper, we report the first such a case treated in Spain in the context of a controlled, randomized, multicenter international study aimed at investigating the usefulness and safety of a bioartificial liver support system based on cryopreserved porcine hepatocytes in patients with acute liver failure or having a non-functioning primary graft after liver transplantation. RESULTS: In this first experience, two sessions of treatment could be completed before a patient with acute liver failure underwent a successful emergency liver transplantation. After more than two years of follow-up, the patient is in her normal life activities and she has not presented any adverse event related to the bioartificial liver support therapy so far. CONCLUSION: Bioartificial liver support systems are starting to be available for use in clinical practice. Yet it is mandatory to establish their safety and efficacy before a widespread recommendation.

Cardiovascular tissue banking in the non-cadaveric setting: ten-year experience of a university hospital-based bank with active organ donation program.

BACKGROUND AND AIM OF THE STUDY: Today, transplantation of cardiovascular tissues is common practice, and tissue banking has become routine. Consequently, many institutions exist which carry out high-quality tissue banking. METHODS: The Hospital Clinico of the University of Barcelona established its cardiovascular tissue bank in 1989. The bank follows international and national regulations, and functions as a non-profit-making organization. Organ and tissue donors are recruited by the Transplant Coordination unit, which works closely with the Catalonian Organ Transplant Network (OCAT) and the Spanish National Organ Transplantation Network (ONT). The hearts are removed during multi-organ donation and processed using aseptic techniques in a laminar flow hood. Hearts are only accepted from brain-dead multiorgan and non-beating-heart donors. The heart valves are dissected, decontaminated, cryopreserved in specific media and stored in liquid nitrogen at -196 degrees C under strict bacteriological and serological control. RESULTS: Between 1989 and 1999, a series of 1,005 cardiovascular donors from within Spain was identified, from which 840 hearts were processed. After evaluation, 1,099 (65.4%) valves were cryopreserved, and 1,023 (61.5%) given clearance for implantation. In total, 534 aortic, 530 pulmonary, 33 mitral and two tricuspid valves were processed; ultimately 92.8% of aortic and 93.9% of pulmonary valves were accepted for clinical implantation. The rejection rate was 39.1%. Homografts were transported to their destination in dry ice in a cryogenic container. Overall, 608 valves were implanted at our own institution and at hospitals in Barcelona and Europe. Only two cases of complaint were received from implanting surgeons. CONCLUSION: After ten years' experience, the degree of satisfaction of implanting surgeons appears to be adequate. Strict control of the entire tissue banking process has permitted the availability of high-quality homografts for clinical implantation.

Changes in the cooling rate and medium improve the vascular function in cryopreserved porcine femoral arteries.

PURPOSE: The purpose of this study was to design an adequate technique with which to cryopreserve pig femoral arteries and to assess the influence of storage times in vascular function. METHODS: Fifty-two femoral arteries were distributed in seven groups. In group A (control), 10 arteries were studied after harvest; in groups B1 and B2, 19 arteries were suspended in RPMI 1640 plus fetal calf serum plus dimethylsulfoxide and were cryopreserved at 1 degrees C per minute or 0.3 degrees C per minute, respectively. In groups C1 to C4, 23 arteries were suspended in modified Krebs-Henseleit plus dimethylsulfoxide plus sucrose, cryopreserved at 0.7 degrees C per minute, and kept frozen for 1, 15, 60, or 180 days, respectively. After being thawed, arteries were examined for contraction and endothelial-dependent vasodilation (organ bath studies), antithrombotic properties of the endothelial layer(perfusion studies), and vessel structure (electron microscopy). RESULTS: Endothelial cells were present in both cryopreserved and control arteries. The control vessels showed a mean contraction to norepinephrine (10(-7) mol/L) of 13010 +/- 3181 mg. Arteries in groups B1 and B2 did not respond to norepinephrine. Contraction in groups C1 to C4 was as follows: C1, 5354 +/- 1222 mg; C2, 5187 +/- 2672 mg; C3, 6867 +/- 2292 mg; C4, 7000 +/- 2858 mg, which represent 50% of the control values (P <.001). Vasodilation was similar in control (99% +/- 3%) and cryopreserved arteries (C1, 90% +/- 13%; C2, 93% +/- 12%; C3, 89% +/- 15%; C4, 88% +/- 22%). Storage time did not influence vascular function. Platelet interaction was almost absent and similar in all groups. CONCLUSION: A modified cryopreservation technique preserves endothelial function independently of the storage time up to 6 months.

Taspine is the cicatrizant principle in Sangre de Grado extracted from Croton lechleri.

Sangre de Grado extract used by Peruvian natives as a cicatrizant agent, was collected from trees of the species Croton lechleri growing in the Peruvian jungle. The Sangre de Grado was found to contain one alkaloid identified as taspine and which was shown to be the active cicatrizant principle by an in vivo test in mice. This alkaloid exhibited a dose-related cicatrizant effect and an ED50 of 0.375 mg/kg. Experiments with taspine hydrochloride in order to study its mechanism of action in cell culture systems showed that the alkaloid was non-toxic to human foreskin fibroblasts at concentrations below 150 ng/ml and that it had no effect on cell proliferation. On the other hand, taspine hydrochloride was found to increase the migration of human foreskin fibroblasts. This effect on the migration of fibroblasts is probably the mechanism by which Sangre de Grado and taspine hydrochloride accelerate the wound healing process. Using the two-stage mouse skin carcinogenesis system, we have been able to show that neither Sangre de Grado nor taspine hydrochloride had carcinogenic or tumour promoter activity after 17 months of treatment.