Zoledronate treatment duration is linked to bisphosphonate-related osteonecrosis of the jaw prevalence in rice rats with generalized periodontitis.

OBJECTIVES: To determine the extent that zoledronate (ZOL) dose and duration is associated with bisphosphonate-related osteonecrosis of the jaw (BRONJ) prevalence in rice rats with generalized periodontitis (PD), characterize structural and tissue-level features of BRONJ-like lesions in this model, and examine the specific anti-resorptive role of ZOL in BRONJ. MATERIALS AND METHODS: Rice rats (n = 228) consumed high sucrose-casein diet to enhance generalized PD. Groups of rats received 0, 8, 20, 50 or 125 µg/kg IV ZOL/4 weeks encompassing osteoporosis and oncology ZOL doses. Rats from each dose group (n = 9-16) were necropsied after 12, 18, 24 and 30 weeks of treatment. BRONJ-like lesion prevalence and tissue-level features were assessed grossly, histopathologically and by MicroCT. ZOL bone turnover effects were assessed by femoral peripheral quantitative computed tomography, serum bone turnover marker ELISAs and osteoclast immunolabelling. RESULTS: Prevalence of BRONJ-like lesions was significantly associated with (a) ZOL treatment duration, but plateaued at the lowest oncologic dose, and (b) there was a similar dose-related plateau in the systemic anti-resorptive effect of ZOL. ZOL and BRONJ-like lesions also altered the structural and tissue-level features of the jaw. CONCLUSION: The relationship between BRONJ-like lesion prevalence and ZOL dose and duration varies depending on the co- or pre-existing oral risk factor. At clinically relevant doses of ZOL, BRONJ-like lesions are associated with anti-resorptive activity.

Comparison of Isoflurane, Ketamine-Dexmedetomidine, and Ketamine-Xylazine for General Anesthesia during Oral Procedures in Rice Rats (Oryzomys palustris).

Rice rats (Oryzomys palustris) are an unconventional laboratory species that has been used to study photoperiodicity, periodontitis, and osteonecrosis of the jaw. Interventional procedures that require anesthesia, including oral procedures, are sometimes necessary in preclinical settings. The use of anesthetics including isoflurane and ketamine combined with α2-adrenoreceptor agonists, such as dexmedetomidine and xylazine, is well-established for laboratory rodents. However, their effects have been studied only modestly in rice rats. The aims of this study were to 1) determine the safety and consistency of 3 common anesthetic modalities in rice rats; 2) compare the physiologic and clinical responses to these anesthetics, and 3) verify the effectiveness of the most successful modality by testing it during an oral procedure (tooth extraction). Isoflurane, intraperitoneal ketamine-dexmedetomidine, and intraperitoneal ketamine-xylazine were evaluated by using a crossover design, in which each rat received all of the anesthetics. Compared with ketamine-dexmedetomidine and ketamine-xylazine, isoflurane inhalation through a nose cone produced more rapid induction, entry to a surgical plane of anesthesia, and initial recovery. In addition, isoflurane produced optimal anesthesia throughout the procedure for most rats. Unlike ketamine-dexmedetomidine and ketamine-xylazine, isoflurane did not alter rectal temperature, SpO2, or respiratory rate during the surgical tolerance period, whereas ketamine-dexmedetomidine and ketamine-xylazine decreased rectal temperature during the last stage of anesthesia and induced cardiorespiratory depression. Furthermore, 2 rats experienced negative outcomes warranting euthanasia: one after receiving ketamine-dexmedetomidine, and the other after ketamine-xylazine anesthesia. In conclusion, isoflurane was the most reliable and effective anesthetic in rice rats and maintained a surgical depth of anesthesia for as long as 30 min, thus supporting successful tooth extractions.

Prevalence of Food Impaction-Induced Periodontitis in Conventionally Housed Marsh Rice Rats (Oryzomys palustris).

Marsh rice rats (Oryzomys palustris) fed a pelleted diet high in sucrose and casein have been used as a model for moderate to severe periodontitis. Here we characterize the prevalence, location, and histopathologic features of food-impaction lesions (FIL), a unique type of oral event, in rice rats fed standard pelleted rodent chow from weaning until 34 wk of age. Healthy female rats (n = 90; age, 4 wk) were weaned into groups (n = 10 to 24) and were euthanized at 4, 16, 22, 28, or 34 wk of age. At necropsy, high-resolution photographs of the 4 jaw quadrants were examined by 3 independent observers to determine the presence, number, and location of FIL. In addition, gross periodontitis was scored (scale, 0 to 4), and the hemimaxillar surface area containing FIL was measured. Serial sections of decalcified jaws were assessed histologically. The prevalence of FIL increased with age, and was 0% (baseline), 59.1%, 69.6%, 81.8% and 80.0% in rats at age 4, 16, 22, 28, and 34 wk, respectively. FIL were predominantly located (93.9%) in the maxillary palatal surfaces of the interproximal area between molars 2 and 3 and did not affect mandibular surfaces. The percentage of the hemimaxillar surface area occupied by FIL was 6.83%, 4.82%, 2.88%, and 6.52% in rats at age 16, 22, 28, and 34 wk, respectively. Histopathologic changes in FIL varied from localized gingivitis to larger, localized periodontitis-like lesions. These data indicate that FIL are common in rice rats fed standard rodent chow, are slight to mild in severity, and are localized to specific regions in the oral cavity, thus suggesting they may be a suitable model for local maxillary periodontitis when fed standard rodent chow.

Geographic distribution of Angiostrongylus cantonensis in wild rats (Rattus rattus) and terrestrial snails in Florida, USA.

The parasitic nematode Angiostrongylus cantonensis is a major cause of eosinophilic meningitis in humans, and has been documented in other incidental hosts such as birds, horses, dogs and non-human primates. It is endemic in Hawaii, and there have been sporadic reports in the southern continental United States. This parasite uses rats as definitive hosts and snails as intermediate hosts. In this study, we collected potential definitive and intermediate hosts throughout Florida to ascertain the geographic distribution in the state: Rats, environmental rat fecal samples, and snails were collected from 18 counties throughout the state. Classical diagnostics and morphological identification, along with molecular techniques were used to identify nematode species and confirm the presence of A. cantonensis. Of the 171 Rattus rattus collected, 39 (22.8%) were positive for A. cantonensis, and 6 of the 37 (16.2%) environmental rat fecal samples collected in three of the surveyed counties were also positive for this parasite by real time PCR. We examined 1,437 gastropods, which represented 32 species; 27 (1.9%) were positive for A. cantonensis from multiple sites across Florida. Three non-native gastropod species, Bradybaena similaris, Zachrysia provisoria, and Paropeas achatinaceum, and three native gastropod species, Succinea floridana, Ventridens demissus, and Zonitoides arboreus, which are newly recorded intermediate hosts for the parasite, were positive for A. cantonensis. This study indicates that A. cantonensis is established in Florida through the finding of adult and larval stages in definitive and intermediate hosts, respectively, throughout the state. The ability for this historically subtropical nematode to thrive in a more temperate climate is alarming, however as the climate changes and average temperatures rise, gastropod distributions will probably expand, leading to the spread of this parasite in more temperate areas. Through greater awareness of host species and prevalence of A. cantonensis in the United States, potential accidental infections may be avoided.

Síndrome de encefalopatía posterior reversible en el postparto. Estudio de caso / Posterior reversible encephalopathy syndrome in postpartum. Case study

El objetivo del presente ensayo es evaluar el síndrome de encefalopatía posterior reversible en el posparto en una paciente de 22 años, sin antecedentes patológicos personales, antecedentes ginecoobstetricos G(1), C(1), A(0), P(0). Antecedente quirúrgico, cesárea segmentaria de 39 semanas de gestación que es referida por presentar cuadro clínico de 24 horas posteriores a la cesárea segmentaria con dolor abdominal, vómitos y distensión abdominal por lo que es intervenida quirúrgicamente donde realizan re-lapartomias para control de daños. Es ingresada a la Unidad de terapia intensiva con apoyo ventilatorio y sin apoyo vasopresor. Se le realiza Angioresonancia evidenciándose, en secuencia s3DI MC, se identifican las arterias cerebrales anteriores, arterias cerebrales medias, arterias comunicantes posteriores, arteria comunicante anterior y el segmento P1, P2 de la arteria cerebral posterior bilateral con diámetros trayectos conservados. Sin embargo, llama la atención la disminución del diámetro de las arterias corticales de las arterias cerebrales posteriores segmento P3 bilateral. Se concluye que el conocimiento del PRES debe ser extenso y de amplia difusión, de modo que todos los actores relacionados con el cuidado de la salud materna identifiquen de forma precoz y oportuna la condición, reducir la morbimortalidad materna y las secuelas neurológicas a largo plazo(AU)

The objective of this trial is to evaluate the posterior reversible encephalopathy syndrome in the postpartum in a 22-yearold patient, with no personal medical history, G (1), C (1), A (0), P (0). Surgical history, segmental cesarean section of 39 weeks of gestation that is referred for presenting a clinical picture 24 hours after segmental cesarean section with abdominal pain, vomiting and abdominal distension, for which she undergoes surgery where re-lapartomies are performed for damage control. She admitted to the intensive care unit with ventilator support and without vasopressor support. Angioresonance performed, showing, in s3DI MC sequence, the anterior cerebral arteries, middle cerebral arteries, posterior communicating arteries, anterior communicating artery and segment P1, P2 of the bilateral posterior cerebral artery with preserved trajectory diameters identified. However, the reduction in the diameter of the cortical arteries of the bilateral posterior cerebral arteries segment P3 is striking. It concluded that the knowledge of PRES should be extensive and widely disseminated, so that all actors related to maternal health care identify the condition early and in a timely manner, reduce maternal morbidity and mortality and longterm neurological sequelae(AU)

Plasma and synovial fluid endothelin-1 and nitric oxide concentrations in horses with and without joint disease.

OBJECTIVE: To compare plasma and synovial fluid endothelin-1 (ET-1) and nitric oxide (NO) concentrations in clinically normal horses and horses with joint disease. ANIMALS: 36 horses with joint disease, and 15 horses without joint disease. PROCEDURE: Horses with joint disease were assigned to 1 of the 3 groups (ie, synovitis, degenerative joint disease [DJD], or joint sepsis groups) on the basis of findings on clinical and radiographic examination and synovial fluid analysis. Endothelin-1 and NO concentrations were measured in plasma from blood samples, collected from the jugular vein and ipsilateral cephalic or saphenous vein of the limb with an affected or unaffected joint, as well as in synovial fluid samples obtained via arthrocentesis from the involved joint. RESULTS: Plasma ET-1 concentrations between affected and unaffected groups were not significantly different. Median concentration and concentration range of ET-1 in synovial fluid obtained from the joint sepsis group (35.830 pg/mL, 7926 to 86.614 pg/mL; n = 7) were significantly greater than values from the synovitis (17.531 pg/mL, 0.01 to 46.908 pg/mL; 18), DJD (22.858 pg/mL, 0.01 to 49.990 pg/mL; 10), and unaffected (10.547 pg/mL, 0.01 to 35.927 pg/mL; 10) groups. Plasma and synovial fluid NO concentrations between affected and unaffected groups were not significantly different. CONCLUSIONS AND CLINICAL RELEVANCE: Endothelin-1 is locally synthesized in the joints of horses with various types of joint disease. Synovial fluid concentrations of ET-1 varied among horses with joint disease, with concentrations significantly higher in the synovial fluid of horses with joint sepsis. These results indicate that ET-1 may play a role in the pathophysiologic mechanism of joint disease in horses.

[Validation of the Diagnostic Interview for Genetic Studies (DIGS) in Colombia]. / Validación de la entrevista diagnóstica para estudios genéticos (DIGS) en Colombia.

An interview tool, Diagnostic Interview for Genetic Studies (DIGS 3.0), was translated into Spanish for application in studies of psychiatric disorders in Colombia. Two Spanish translations of the original English version of DIGS were prepared and back-translated into English. A review committee verified the linguistic and cultural equivalence of the translations. The evaluator and test-retest reliability were assessed calculating Cohen's kappa for samples of 65 and 91 patients respectively. DIGS proved valid in both appearance and content. The confidence interval (C.I.) was excellent for schizophrenia (kappa = 0.81, C.I. 95% = 0.68-0.93), bipolar disorder (kappa = 0.87, C.I. 95% = 0.75-0.99), major depressive disorder (kappa = 0.86, C.I. 95% = 0.70-1.00), and for a normal diagnosis (kappa = 0.65, C.I. 95% = 0.41-0.89); it was good for other psychiatric diagnosis (kappa = 0.65, C.I. 95% = 0.41-0.89) and poor for schizoaffective disorder (kappa = 0.37, C.I. 95% = -0.02-0.76). Test-retest reliability was excellent for all diagnoses (kappa > 0.8), except for "other psychiatric diagnoses" (kappa = 0.64, C.I. 95% = 0.31-0.96). The Spanish translation of the DIGS was comprehensible, with face and content validity, and good test-retest and evaluator reliability. This translation will be a useful tool for genetic studies of psychiatric disorders in Latin America, particularly where schizophrenia and affective disorders are involved.

Validación del “inventario de razones para vivir” (RFL) en sujetos con conducta suicida de Colombia / Validation of the Reasons for Living Inventory (Rfl) in subjects with suicidal behavior in Colombia

Objetivo: Evaluar la estructura factorial, la confiabilidad y la validez de contenido y constructo de una versión en español para Colombia del Inventario de Razones para Vivir (Rfl) en una muestra clínica de sujetos con intento de suicidio. Método: Se hicieron dos traducciones al español y dos traducciones en sentido inverso de cada uno de los ítems. Se examinó la validez del contenido y del constructo, la consistencia interna y la reproducibilidad prueba-reprueba. Resultados: La estructura factorial tiene seis dominios que explican el 63,5% de la varianza: “Creencia en la vida y capacidad de afrontamiento”, “Miedo a la muerte y a la desaprobación social”, “Responsabilidad con la familia”, “Preocupación por los hijos”, “Percepción de incapacidad para el suicidio” y “Objeciones morales”. La consistencia interna fue alta (Alfa de Cronbach=0,96), así como la reproducibilidad prueba-reprueba (CCI=0,89, IC95%: 0,78-0,94). Cuando se evaluó la validez del constructo encontramos diferencias significativas en las puntuaciones del Rflentre individuos con riesgo de suicidio alto y bajo, definido clínicamente. Conclusiones: La versión colombiana del Rflmuestra buenas propiedades psicométricas en una población clínica con comportamiento suicida.

Objective: To evaluate the factor structure, reliability, and construct and content validity of the Colombian Spanish version of the Reasons for Living Inventory (Rfl) in a clinical sample of subjects who attempted suicide. Method: Two translations into Spanish and two back-translations for each of the items were done. We assessed content and construct validity as well as internal consistency and test-retest reproducibility. Results: The factor structure has six domains which explain 63.5% of the variance: “survival and coping beliefs”, “fear of death and social disapproval”, “responsibility to family”, “child-related concerns”, “perception of incapacity for suicide” and “moral objections”. The internal consistency was high (Cronbach’s alpha=0.96), as was test-retest reproducibility (ICC=0.89, IC95%: 0.78-0.94). When assessing construct validity, we found significant differences between individuals with clinically defined high and low suicide risk in Rflscores. Conclusions: The Rflversion for Colombia shows good psychometric properties in clinical population with suicidal behavior.

Características asociadas al riesgo de suicidio valorado clínicamente en personas con intento reciente / Clinical Assessment of Suicidal Risk in Subjects with a Recent Suicide Attempt

Objetivos: Describir en un grupo de sujetos que ingresaron por intento de suicidio a los servicios de urgencias de diferentes centros asistenciales de Medellín (Colombia), las características de aquéllos clasifi cados en la evaluación clínica psiquiátrica como de alto y bajo riesgo de reincidencia. Métodos: Estudio de corte transversal. Se hizo entrevista psiquiátrica a 238 individuos con intento de suicidio reciente para clasifi carlos en dos grupos, de alto y bajo riesgo de reincidencia, y se aplicó el instrumento de autorreporte “inventario de razones para vivir” (RFL). Posteriormente, se compararon las características de ambos grupos. Resultados: El 60,5% de los participantes se consideraron de alto riesgo de suicidio y los factores que se encontraron asociados fueron: trastorno depresivo mayor (OR=5,78, IC95%: 3,01-11,2), método violento (OR=5,21, IC95%: 1,89-14,37), intoxicación por sustancias psicoactivas durante el intento (OR=2,46, IC95%: 1,07-5,64) y puntuación en el “inventario de razones para vivir” (OR=0,47, IC95%: 0,34- 0,66). Conclusiones: Aunque los resultados no son generalizables, son similares a los encontrados en otros lugares. Es necesario hacer estudios longitudinales que permitan determinar la utilidad de estas características para predecir conductas suicidas.

Objectives: To describe the characteristics that rendered subjects as having either high risk or low risk of suicide, according to the psychiatric evaluation performed after a suicidal attempt in different emergency services in Medellín, Colombia. Methods: It is a cross-sectional design. 238 individuals were interviewed to classify them in a group of high suicide risk or a group of low suicide risk. The self-report scale “Reasons for Living Inventory” (RFL) was applied. After that, characteristics of the high and low risk groups were compared. Results: The 60.5% of the participants were classifi ed as high risk attempters. The factors associated with high risk were: major depressive disorder (OR=5.78, CI 95%: 3.01-11.2), violent method (OR=5.21, CI 95%: 1.89-14.37), attempt during psychoactive substance intoxication (OR=2.46, CI95%: 1.07-5.64) and score of the “Reasons for Living Inventory” (OR=0.47, IC95%: 0.34-0.66). Conclusions: The results are similar to those reported in studies carried out in other places. Further longitudinal studies are required for determining the utility of these characteristics to predict future suicidal behavior.

Validación de la entrevista diagnóstica para estudios genéticos (DIGS) en Colombia / Validation of the Diagnostic Interview for Genetic Studies (DIGS) in Colombia

Objetivo: validar la entrevista diagnóstica para estudios genéticos (DIGS 3.0) en Colombia. Métodos: se hicieron dos traducciones del inglés al español del DIGS y se hizo traducción en sentido inverso (al inglés) de cada una. Un comité de revisión verificó la equivalencia translingüística y transcultural. Se evaluó la confiabilidad examen-reexamen e interevaluador del DIGS 3.0 en 65 y 91 pacientes, respectivamente, mediante el cálculo de kappa de Cohen. Resultados: el DIGS 3.0 mostró ser comprensible, con validez de apariencia y de contenido. La confiabilidad interevaluador fue excelente para esquizofrenia (kapa=0,81, IC95%: 0,68-0,93), trastorno bipolar (kapa=0,87, IC95%: 0,75-0,99), trastorno depresivo mayor (kapa=0,86, IC95%: 0,7- 1) y ausencia de trastorno psiquiátrico (kapa=0,88, IC95%: 0,71-1); fue buena para otro diagnóstico psiquiátrico (kapa=0,65, IC95%: 0,41-0,89) y pobre para trastorno esquizoafectivo (kapa=0,37, IC95%: -0,02-0,76). La confiabilidad examen-reexamen fue excelente para todos los diagnósticos (kapa>0,8), excepto para otro diagnóstico psiquiátrico (kapa=0,64, IC95%: 0,31-0,96), donde fue buena. Conclusiones: la versión en español del DIGS para Colombia mostró comprensibilidad, validez de apariencia y de contenido, y confiabilidad examen-reexamen e interevaluador. Es una herramienta útil para estudios genéticos en esquizofrenia y en trastornos afectivos.

An interview tool, Diagnostic Interview for Genetic Studies (DIGS 3.0), was translated into Spanish for application in studies of psychiatric disorders in Colombia. Two Spanish translations of the original English version of DIGS were prepared and backtranslated into English. A review committee verified the linguistic and cultural equivalence of the translations. The evaluator and test-retest reliability were assessed calculating Cohen’s kappa for samples of 65 and 91 patients respectively. DIGS proved valid in both appearance and content. The confidence interval (C.I.) was excellent for schizophrenia (kappa=0.81, C.I. 95% = 0.68-0.93), bipolar disorder (kappa=0.87, C.I. 95% = 0.75-0.99), major depressive disorder (kappa=0.86, C.I. 95% = 0.70-1.00), and for a normal diagnosis (kappa=0.65, C.I. 95% = 0.41-0.89); it was good for other psychiatric diagnosis (kappa=0.65, C.I. 95% = 0.41-0.89) and poor for schizoaffective disorder (kappa=0.37, C.I. 95% = -0.02-0.76). Test-retest reliability was excellent for all diagnoses (kappa>0.8), except for "other psychiatric diagnoses" (kappa=0.64, C.I. 95% = 0.31-0.96). The Spanish translation of the DIGS was comprehensible, with face and content validity, and good test-retest and evaluator reliability. This translation will be a useful tool for genetic studies of psychiatric disorders in Latin America, particularly where schizophrenia and affective disorders are involved.

Colecistitis agudas: Actuales bases etiológicas, diagnósticas y terapéuticas

La colecistitis aguda es una de las patologías más frecuentes en el ámbito de la Cirugía de Urgencias. A pesar de la generalización de la colecistomía como tratamiento de la litiasis vesicular, el porcentaje de colecistitis agudas no ha variado durante los últimos años. Los autores revisan las características clínicas y diagnósticas de esta enfermedad así como los nuevos conceptos en el tratamiento de la misma, y exponen su propia experiencia en esta patología.

Peritonitis biliar tras la retirada del tubo en T / Biliary peritonitis following T tube removal

La proteccion de una sutura biliar con tubo en T (kehr), es una practica habitual en cirugia digestiva. Normalmente es un drenaje que no presenta complicaciones. El proposito de esta comunicacion es presentar dos casos de peritonitis biliar tras retirada electiva de un tubo de kehr. Esta es una rara y grave complicacion que requiere un diagnostico precoz y correccion quirurgica inmediata

Tratamiento local del cáncer de recto / Local treatment of rectal cancer

La aplicación de protocolos de cribado ha determinado que el número de tumores de recto diagnosticados tempranamente haya aumentado de forma significativa. Consecuentemente, el tratamiento local de estos tumores tempranos ha pasado a ocupar un lugar destacado dentro de la terapéutica del cáncer de recto. Este artículo realiza una revisión de las indicaciones del tratamiento local, de las técnicas diagnósticas y terapéuticas disponibles y de sus resultados. La selección de candidatos ha de llevarse a cabo de manera rigurosa mediante la exploración clínica, la biopsia preoperatoria, la ecografía endorrectal y la utilización de otros procedimientos radiológicos. La destrucción tumoral mediante fulguración o radioterapia endocavitaria obtiene resultados similares a la escisión local. Sin embargo, el estudio patológico del tumor resulta imprescindible para identificar a aquellos pacientes que pueden necesitar un tratamiento quirúrgico radical, o que pueden beneficiarse de un protocolo de tratamiento radioquimioterápico adyuvante. La tasa de recidiva local tras estos procedimientos es mayor que la que corresponde a la cirugía radical. Aunque la mayoría de las recidivas son potencialmente resecables, el papel de la cirugía radical de rescate está en discusión. (AU)

En busqueda de los genes bipolares / Looking for the bipolar genes

Objetivos: Caracterizar una muestra de familias y tríos de una población colombiana aislada para mapear loci involucrados en la vulnerabilidad al Transtorno Bipolar tipo I (TAB-I). Se evaluaron endofenotipos clínicos, neuropsicológicos y moleculares, para acortar el camino entre la identificación de genes y sus expressiones fenotípicas, y luego se realizaron estudios de ligamiento. Métodos: Se recolectaron tríos y genealogías utilizando las entrevistas FIGS-DIGS en miembros de familias y sus posibles afectados. El poder para detectar ligamiento (PDL) se estimó por simulación. Como endofenotipos clínicos comparamos casos de TAB-I con agregación familiar y controles sin agregación. Realizamos una evaluación neuropsicológica comparativa en casos eutímicos y controles sanos. Evaluamos el polimorfismo de longitud del gen del promotor del receptor de serotonina (5HTTLP) y la asociación con el TAB-I. Luego estudiamos el desequilibrio promedio en tríos y familias tamizando los cromosomas 12, 18 y 21.Resultados:Se identificaron 28 familias co TAB-I, asumiendo homogencidad genetica y la evidencia de mestizaje recientemente hallada por nosotros, las simulaciones mostraron PDL significativo de 100 por cento para un LOD-score menor 3. En la población con TAB-I familiar se encontró peor funcionamiento intercrítico, mayor gravedad en episodios depresivos, disfunción neuropsicológica en eutímia y posible evidencia de ligamiento al cromosoma 21 q 22.3. Conclusión : Tenemos un grupo significativo de familias y tríos pertenecientes a una población aislada con un poder para detectar ligamiento al Trastorno Anímico Bipolar. Las características de esta población y los hallazgos actuales en ella sugieren gran probabilidad de encontrar rasgos de expresión clínica y neuropsicológica y genes de susceptibilidad al TAB-I. En el barrido genómico que llevamos a cabo actualmente pretendemos profundizar estos hallazgos.

Lente electromagnética en telecomunicaciones

En el presente trabajo se desarrolla la base teórica de la lente electromagnética y su aplicación a un tramo montañoso (Yumia-Cerro Corral Colorado-Villazon) del sistema de microondas. También sirve como un marco de referencia suceptible de ser utilizado en estudios de telecomunicaciones en condiciones topográficas de montaña. La descripción de la zona geográfica donde se podría aplicar la lente electromagnética en la solución de un problema concreto de obstrucción lo efectuamos en el cap. IV y con el fin de fundamentar la conveniencia de su instalación para integrar parte de nuestro territorio al resto del pais mediante el sistema de microondas partimos de un análisis necesario de los antecedentes técnicos que refuerzan las bondades del uso de la lente electromagnética señaladas en el cap. I.