Organ Donation and Primary Central Nervous System Tumors.

Primary central nervous system tumors can be the cause of brain death. Not all of them contraindicate the donation of organs and tissues for transplant. A survey of cases was carried out in our country in which it was observed that the number of brain deaths caused by primary tumors was low, of the order of 2%, with an x (media) of 3 by year, which would increase the potential for donation. Medical records, an anatomopathologic study, and a detailed physical examination will be fundamental when applying the donor selection criteria. Nuclear magnetic resonance in expert hands has a sensitivity of 96% to catalog the benignity or malignancy of this type of tumors.

Organ Use Rate: A New Indicator of Donation and Transplantation Efficiency.

The conversion rate has emerged as a good indicator of the effectiveness of the transplantation process by showing the percentage of potential donors who become real donors, but it overestimates the number of organs that are actually used for transplantation in recipients. The incorporation of organ use rate, a new quality indicator that reflects the actual number of organs used for transplantation excluding those that are discarded in the surgical block, provides complementary information of great value when comparing transplantation in different regions. This new variable allows more accurate prediction of the waiting time for the transplantation of a certain organ in patients with nonreversible organic insufficiencies, while providing the national authorities a real response in relation to the percentage of the demand for organs that can be satisfied.

Prediction of the Evolution to Brain Death in the Neurocritical Patient: SPN Model Showed Better Performance Than Simplified Acute Physiology Score II and Acute Physiology and Chronic Health Evaluation II.

The detection of brain death (BD) plays a fundamental role in the management of hospital donation. Delayed diagnosis of BD is the main cause of donor loss. A tool for monitoring and prognosis in the neurocritical patient is essential to meet these objectives. The most used prognostic scores in intensive care units are Simplified Acute Physiology Score (SAPS) II and Acute Physiology and Chronic Health Evaluation (APACHE) II. A predictive model of good performance (ModSPN) in predicting BD in neurocritical patients with Glasgow Coma Scale score < 8 was published in 2014. With the objective of analyzing the predictive capacity of ModSPN and comparing it with SAPS II and APACHE II, 2307 patients admitted to the neurocritical patient monitoring (SPN) program of the INDT were analyzed. The predictive capacity for death and brain death of SAPS II, APACHE II, and ModSPN was compared using receiver operating characteristic curves. The area under the curve showed a better APACHE II performance for the prediction of death and the ModSPN being a better predictor of the probability of dying in BD. Therefore, for the prediction of death in the neurocritical patient, APACHE II was superior, but for the prediction of encephalic death, the ModSPN presented the best predictive power for all causes of brain injury.

Development of the National Kidney Transplantation Program in Uruguay.

The first kidney transplantation (KT) in Uruguay was performed in 1969. We report the rates of KT and survival of patients and grafts up to December 2014. The country has a surface of 176,215 km(2) and a population of 3,286,314 inhabitants (18.6 inhabitants per km(2)). Till December 31, 2014, 1,940 KT have been performed in Uruguay (41.8 pmp that year); 90.4% of them were from cadaveric donors (CD). Median age of recipients (R) was 44 ± 14 years; R older than 55 years increased from 0 to 27% during the period. Our pre-emptive KT program started in 2007. Optimal donors (D) decreased from 65.2% to 35.5%, and D older than 45 years old increased from 9% to 37%. Trauma as cause of death decreased from 49% to 32% and stroke as cause of death increased from 25% to 39%. Patient survival rates at 1, 5, and 8 years were 93%, 87%, and 78%, respectively for KT performed between 1980 and 1989; they were 98%, 93%, and 89%, respectively, for KT performed between 1990 and1999; they were 97%, 91%, and 90%, respectively, for KT performed between 2000 and 2010. In December 2013, there were 1098 patients pmp in renal replacement therapy, 758 pmp in dialysis, and 340 pmp (30.9%) with a functioning graft. Our national KT program is mainly based (90.6%) on cadaveric donation. Epidemiological changes in the characteristics of R and D followed the changes in aging that occurred in the general population and the dialysis population. The survival rates from patients and kidneys are similar to those reported by the European and the American registries.

Laparoscopic biliopancreatic diversion with duodenal switch: technique and initial experience.

BACKGROUND: The duodenal Switch (DS) is a variant of the biliopancreatic diversion (BPD) for the surgical treatment of morbid obesity. MATERIALS AND METHODS: The laparoscopic DS (LapDS) operation is described, and the early surgical outcomes of 16 patients are reported. RESULTS: Postoperative stay was 5 to 8 days. Local wound infection at a trocar site was the most common local complication. CONCLUSION: LapDS is an advanced, complex and feasible technique in bariatric surgery.

Vertical banded gastroplasty at more than 5 years.

BACKGROUND: Optimal evaluation of the results of surgery for morbid obesity requires a long-term follow-up for at least 5 years. METHODS: One hundred patients were operated by vertical banded gastroplasty (VBG) and revised with a follow-up of no less than 5 years. Sixty patients were morbidly obese with a body mass index (BMI) of between 40 and 50 kg/m2, and 40 were super-obese with a BMI of >50 kg/m2. Follow-up included 93 patients (93%). RESULTS: Initial surgical mortality was nil. Twenty-five patients required surgery for complications related to the technique (25%) and one patient died due to pulmonary embolism after a re-stapling operation. The percentage excess weight loss was 54.3%, and the BMI was 33 kg/m2 for the 84 patients followed to 5 years post VBG. Only 40 out of 92 patients (43.5%), obtained the weight loss benefit due to the operation. None of them is able to eat a regular diet, and the quality of food intake has been severely affected in some of them. CONCLUSIONS: VBG is, in our experience, a safe and technically simple operation, but the long-term results are questionable. The reoperation rate was high, and weight loss and quality of life are superior with other operations.

Duodenal switch: an effective therapy for morbid obesity--intermediate results.

BACKGROUND: The duodenal switch (DS) is a variant of the biliopancreatic diversion (BPD), with a vertical subtotal gastrectomy and pylorus preservation. METHODS: DS was used to treat morbid obesity in 125 patients, with mean BMI 50, with 65% of the patients super obese (SO). Patients have been followed for an intermediate period. RESULTS: The percentage of excess weight loss (%EWL) was > 70% at 1 year, and reached 81.4% at 5 years when 97% of the patients had a %EWL > 50%. Comorbidities were cured or improved in all patients. CONCLUSION: DS was very effective for the treatment of the morbid obesity in the SO patients.

Hard contact lens wear as an environmental risk in keratoconus.

We studied 162 keratoconus patients in an attempt to clarify the role of hard contact lens wear in the development of keratoconus. Forty-three (26.5%) of these 162 patients developed keratoconus while wearing hard contact lenses. In a group of 1,248 controls who were fitted for soft contact lenses and observed by us from one year to six years, only one patient developed keratoconus. We demonstrated a circumstantial association between hard contact lens wear and the development of keratoconus, but no cause-effect relationship can be drawn from the existing data. However, we concluded that hard contact lenses do not retard or halt progression of the cone. Hard contact lens wear could not be ruled out as the specific environmental risk factor triggering keratoconus in 26.5% of the patients. If we identify the genetic risk present in this subpopulation, eliminating environmental risks would be an effective means of preventing keratoconus in those predisposed individuals.

Review of the Uruguayan Kidney Allocation System: the solution to a complex problem, preliminary data.

The National Kidney Transplant Program with cadaveric donors is based on centralized and unique waitlist, serum bank, and allocation criteria, approved by Instituto Nacional de Donación y Trasplante (INDT) in agreement with clinical teams. The median donor rates over last 3 years is 20 per million population and the median number of waitlist candidates is 450. The increased number of waiting list patients and the rapid aging of our populations demanded strategies for donor acceptance, candidate assignment, and analysis of more efficient and equitable allocation models. The objectives of the new national allocation system were to improve posttransplant patient and graft survivals, allow equal access to transplantation, and reduce waitlist times. The objective of this study was to analyze variables in our current allocation system and to create a mathematical/simulation model to evaluate a new allocation system. We compared candidates and transplanted patients for gender, age, ABO blood group, human leukocyte agents (HLA), percentage of reactive antibodies (PRA), and waiting list and dialysis times. Only 2 factors showed differences: highly sensitized and patients >65 years old (Bernoulli test). An agreement between INDT and Engineering Faculty yielded a major field of study. During 2008 the data analysis and model building began. The waiting list data of the last decade of donors and transplants were processed to develop a virtual model. We used inputs of candidates and donors, with outputs and structure of the simulation system to evaluate the proposed changes. Currently, the INDT and the Mathematics and Statistics Institute are working to develop a simulation model, that is able to analyze our new national allocation system.

Three decades of the history of donation and transplantation in Uruguay.

AIM: The aim of this study was to analyze the evolution of the legal framework, health system of donation, and transplantation of cells, tissues, and organs, measured based on processes and rates from 1978 to 2008 in Uruguay. MATERIALS AND METHODS: We analyzed 3 decades (1978-1988/1989-1998/1999-2008) by the following evaluation: the legislation, donation and transplantation system, procurement, registration of pre-state of voluntary donations, actual donations and transplantation rates of solid organs (kidneys, heart, liver, and pancreas), and rates of donation and transplantation of tissues (corneal and laminar [skin, amniotic membrane, and fascialata]), of cardiovascular elements (valves and vases), and of ostearticular tissues (bones and tendons). RESULTS AND CONCLUSIONS: Uruguay has maintained continuous governmental politics in donation and transplantation. In the last decade the elaboration of a strategic plan by promoting Laws and Decrees of Encephalic Death, Presumed Donation and Security of Cells and Tissues, as well as the creation of the Unit Procurement, the registration of nonrelated donors for hematopoietic stem cells, and the re-engineering of tissue banking, has shown a significant increase in deceased donation and cadaveric transplantation, reaching the first highest overall donor rate in Latin America with 24/pmp multiorgan donors.

Experimental studies on the influence of surfactants on intestinal absorption of drugs. Cefadroxil as model drug and sodium lauryl sulfate as model surfactant: studies in rat colon.

The effect of the anionic surfactant, sodium lauryl sulfate (CAS 151-21-3), on the absorption of cefadroxil (CAS 50370-12-2) as model antibiotic in colon has been studied by means of an in situ rat gut technique, as a previous step to investigate the influence of the surfactant on the intestinal, carrier-mediated absorption of the antibiotic. Microbial degradation tests were initially performed, which demonstrated that cefadroxil disappearance from luminal content was only due to absorption. Micelle solubilization of cefadroxil was also previously assessed through dialysis tests in order to adequately correct absorption rate constant values found in the presence of the surfactant at supramicellar concentration. Micelle solubilization was minimal, although statistically significant. Apparent passive absorption rate constants, ka(h-1), were determined in the presence of variable concentrations of lauryl sulfate in perfusion fluids. Results showed that ka values greatly increased as surfactant luminal concentration increased until an asymptotic value (about 7-fold higher than cefadroxil alone) was obtained; this was assumed to be due to a direct effect of the surfactant on membrane polarity. Moreover, the results were satisfactorily adjusted using a functional hyperbolic-type equation, as occurs with many other saturable processes. This was supposed to be indicative that the surfactant effect is due to an adsorption process of the surfactant ions or molecules to the intestinal absorbent membrane.

Immunologic and osteogeneic properties of xenogeneic and allogeneic demineralized bone transplants.

Xenografting is increasingly being developed as a response to the shortage of human tissues. However, antigenic components of bone material eliciting immune responses--particularly of cellular nature--are blamed for the reduction of the osteoinductive properties of bone and bone-derived implants. The aim of our study was to compare the immunologic response and osteogenesis induced by antigen-depleted allogeneic and xenogeneic bone-derived implants to that induced by partially antigen-depleted material heterotopically placed (muscular pouch) in rats. Wistar rats received bone-derived implants of different antigeneic condition, from both xenogeneic (rabbit) and allogeneic (rat) origin. After sacrifice, animals were evaluated for osteogenesis and immune response. New bone formation was observed around all bone-derived implants, whether fully or partially antigen-extracted, and from both xenogeneic and allogeneic origin. No significant humoral response resulted following bone implantation. Cellular response showed a similar pattern in partial and fully antigen-extracted bone of both allogeneic and xenogeneic origin. Xenogeneic antigen-extracted bone from safe donor sources could be a suitable solution to human tissue shortage in a near future.

Experimental studies on the influence of surfactants on intestinal absorption of drugs. Cefadroxil as model drug and sodium lauryl sulfate as model surfactant: studies in rat duodenum.

The effect of sodium lauryl sulfate (CAS 151-21-3) on the duodenal absorption of cefadroxil (CAS 50370-12-2) has been investigated with the aid of a classical rat gut in situ preparation. Both compounds were entirely compatible in working solutions. Cefadroxil was found to be very stable and only slightly solubilized in the micellar phase. The apparent first-order absorption rate constants for the free antibiotic fraction were determined in free solution, and in the presence of variable surfactant concentration in luminal fluid. A functional interpretation of these data, based both on the law of mass action and the complete noncompetitive transport inhibition equations, showed that the surfactant acts as a nonspecific inhibitor of the carrier-mediated absorption of the antibiotic, but also as an enhancer of its passive absorption component. The net result was an outstanding reduction in the absorption capacity of cefadroxil when it was perfused at 0.1 mg/ml, i.e. far from its carrier saturation (from 3.0 h-1 in free solution to 2.0(-1) at high surfactant concentration, with a minimum of about 1.4 h-1 in the presence of the surfactant at 0.5 mg/mg in duodenal fluid). When cefadroxil was perfused at 10.0 mg/ml, i.e. with its carrier-mediated transport beyond the saturation, the net result was a progressively enhanced absorption (ranging from about 0.9 h-1 in free solution to 2.0 h-1 at high surfactant concentration).(ABSTRACT TRUNCATED AT 250 WORDS)

HLA-A, -B, -DR en receptores de trasplante de médula ósea en Uruguay: Sistema Nacional de registro, tipificación y búsqueda de donantes de médula ósea y progenitores hematopoyéticos (SINDOME) / National System of Recording, Typification and Searching for spina cord donors and hematopoietic progenitors (SINDOME)

Uruguay posee un sistema solidario de financiación de trasplante a través del Fondo Nacional de Recursos y dedl banco Nacional de Órganos y tejidos (BNOT). En el trasplante alogénico de médula ósea la compatibilidad HLA es una barrera biológica importante. Las frecuencias alélicas y haplotípicas HLA son utilizadas para determinar la probabilidad de encontrar un donante con un fenotipo particualr HLA y para predecir el efecto de diversos esquemas de adjudicación basados en la compatibilidad en este sistema. El Laboratorio de Inmunogenética e Histocompatibilidad tipifica a todos los receptores y donantes del país. Se ha iniciado un programa cuyo objetivo central es organizar un sistema de registro, tipificación y búsqueda de donantes no relacionados a nivel nacional (SINDOME). Objetivos: analizar los receptores tipificados para trasplante de médula ósea (TMO) alogénico en nuestro servicio en el período enero 1997 - mayo 2002, y caracterizar la constitución genética del sistema HLA para 298 receptores. Material y método: en el lapso indicado se estudiaron 346 receptores y 1.083 donantes. Se realizó la tipificación HLA clase I por reacción de microlinfocitotoxicidad con anticuerpos monoclonales y la reversa, con nivel de resolución intermedio-alta. Se estimaron las frecuencias alélicas y haplotípicas en una muestra de 298 receptores. Resultados: de los 346 receptores de TMO estudiados en el marco del SINDOME, 58 por ciento es menor de 30 años. La relación donante-receptor fue de 3,13 pero sólo el 45 por ciento de los candidatos a trasplante tuvo un donante histocompatible. En el análisis del polimorfismo ded HLA-A, -B, -DR en la muestra de 298 receptores se encontró que los alelos más prevalentes fueron A2 (28,97 por ciento), B35 812,49 por ciento) y DR04 (15,24 por ciento). Sólo para el locus HLA-DRB1 la desviación del equilibrio de Hardy-Weinberg fue altamente significativa. Los haplotipos más comunes fueron A2-B51 y A2-B7 para HLA-A, -B, A2-DR11 y A2-DR04 para HLA-A -DRB1, y el haplotipo B8-DR03 para HLA-B -DR. De los Hplotipos HLA-A -B -DRB1, HLA-A1 -B8 -DR03 y HLA-A2 -B51 -DR13 fueron los más frecuentes. Conclusión: nuestros resultados demuestran que el sistema HLA presenta una considerable heterogeneidad, con un enorme polimorfismo y una amplia distribución de haplotipos. La posibilidad de encontrar donantes compatibles para un subgrupo de jóvenes con enfermedades malignas sin donantes familiares es muy baja.

El cruce duodenal: una terapia efectiva en la obesidad mórbida. Estudio intermedio / Duodenal switch: an effective therapy for morbid obesity. An intermediate study

El cruce duodenal es una variante de la derivación biliopancreática. Se describen la técnica, su morbimortalidad, los resultados intermedios, los efectos secundarios y las indicaciones como una técnica mixta para el tratamiento de la obesidad mórbida. El porcentaje de sobrepeso perdido se incrementa del 70 por ciento al año hasta el 81,37 por ciento a los 5 años (AU)