RESUMEN
This work studies descriptively the Head Injury Criterion (HIC) and Chest Severity Index (CSI), with a finite element model of the Hybrid III dummy type, for six-year-old subjects in a frontal vehicular collision, using the low-back booster (LBB) passive safety system. The vehicle seats and the passive safety systems were modelled in CAD (computer aided design) software. Then, the elements were analysed by the finite element method (FEM) in LS-DYNA® software. The boundary conditions were established for each study, according to the regulations established by the Federal Motor Vehicle Safety Standard (FMVSS), following the FMVSS 213 standard. The numerical simulations were performed during an interval of 120 ms and recording results every 1 ms. In order to analyse the efficiency of the system, the restraint performance of the LBB system is compared with the restraint configuration of the vehicle safety belt (VSB) only. The obtained injury criteria with the LBB system shows its ability to protect children in a frontal collision. The analyses allow obtaining the deceleration values to which the dummy head and chest was subjected. Of the studies herein performed, Study I: VSB obtained a HIC36 of 730.4 and CSI of 315.5, while Study II: LBB obtained a HIC36 of 554.3 and CSI of 281.9. The outcome shows that the restraint efficiency of each studied case differs. Used materials, the attachment system of the LBB, and the belt restraint system properly placed over the infant trunk are the main factors reducing the injury criteria rate.
RESUMEN
Background: Cytotoxic T lymphocyte antigen-4 (CTLA-4) molecule is an important regulator of T cell activation involved in the down-regulation of immune response. Their polymorphisms +49 A/G and CT60 have been suggested to confer susceptibility to autoimmune endocrine disorders. The aim of this study was to determine the association of CTLA-4 gene polymorphisms with T1D in the Chilean population. We also wanted to study if the combined haplotypes of +49 A/G and CT60 had an impact on risk for T1D. Methods: To evaluate the impact of allelic variants CT60 and +49 A/G SNPs were studied in a Chilean population, including 248 T1D patients and 160 controls. Genotypes of both polymorphisms of CTLA-4 gene were determinate by PCR-restriction fragment polymorphism (PCRRFLP).Results: No statistical differences were observed when comparing patients with diabetes and controls for both CTLA-4 genotypes. However, the haplotype analysis between CT60 and +49 A/G showed an interesting combination of risk conformed by G*G combination with an OR of 1.648 [1.19- 2.28], (p = 0.002). Conclusions: The G*G haplotype could be a risk marker in patients with T1D in Chilean population.
Asunto(s)
Humanos , /genética , Diabetes Mellitus Tipo 1/genética , Polimorfismo Genético , Autoinmunidad , Estudios de Casos y Controles , Chile , Diabetes Mellitus Tipo 1/inmunología , HaplotiposRESUMEN
To determine the serological levels of inflammatory markers and autoimmunity in patients with T1D compared with controls, and determined its relation to the duration of diabetes. Methods: We selected 139 patients with T1D without chronic complications of diabetes, and 110 control subjects without family history of diabetes. Serological ultrasensitive C-reactive protein levels (usCRP), interleukin- 6 and adhesion protein VCAM through ELISA assay were determined. Autoimmune profile was also analyzed through GAD65, IA-2 and ZnT8 autoantibodies. Results: Increased levels of usCRP 1.74 (0.10 to 13.6) vs 1.08 (0.40 to 3.70) ng/ml (p < 0.03), VCAM 236.0 (122.2 to 693.5) vs 185.4 (101.3 to 421.3) ng/ml, p < 0.02 and IL-6 1.73 (0.40 to 9.10) vs 1.28 (0.30 to 4.60) ng/ml, p < 0.05 was found in the group of T1D patients compared with the control group. When analyzing inflammatory markers according to age groups (0-10 years and > 10 years), the values of usCRP were higher in the second group. There was no significant association between patients with DM1 and autoimmune positive profile with a higher frequency of markers of inflammation. Conclusions: These results suggest the presence of pro-inflammatory state is considerably more frequent in patients with T1D. The increased level of usCRP and IL -6 and according to age of the patients could indicate a possible role of adiposity and weight gain during the adolescence in the higher frequency of inflammatory markers in T1D patients...
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Humanos , Masculino , Adolescente , Femenino , Preescolar , Niño , Diabetes Mellitus Tipo 1/inmunología , Glutamato Descarboxilasa/inmunología , /inmunología , Proteína C-Reactiva/inmunología , Autoinmunidad , Autoanticuerpos/análisis , Biomarcadores , Glutamato Descarboxilasa/análisis , Técnicas para Inmunoenzimas , Inflamación , /análisis , Proteína C-Reactiva/análisisRESUMEN
Background: The programmed cell death 1 (PDCD-1) immune-receptor is a key element in the negative regulation of peripheral tolerance in T cells. The gene has several polymorphisms and can be associated with susceptibility to autoimmune diseases. Aim: To analyze the frequency and distribution of PD-1.3 polymorphism of PDCD-1 gene and explore its possible contribution as a susceptibility gene for type 1 diabetes (T1D). Patients and Methods: We analyzed 248 cases with T1D with recent diagnosis and 160 control children under 15 years of Santiago. Genetic polymorphism in PD-1 gene variant for PD-1.3 (rs 11568821) was analyzed by polymerase chain reaction and restriction fragment length polymorphism. Comparison of genotype, allele frequency and consistency with respect to Hardy-Weinberg were analyzed using X2 tests and Fisher exact test. Results: There was a very low frequency of the genotype A/A, both in T1D patients and in controls (< 2 percent). The A/G genotype was more common in diabetic patients than in controls (41.6 and 18.8 percent respectively, p < 0.04). G/G genotype was more common in controls than in patients (79.4 and 56.8 percent respectively, p < 0.02). T1D patients carrying genotype G/G had a higher frequency of anti-GAD65 and anti-A-2 antibodies (81 and 67 percent respectively). Conclusions: The distribution of PD-1.3 genotype frequencies are similar to that reported elsewhere. Possibly, this genetic variant (rs 11568821) does not have an important marker role in Chilean T1D patients.
Asunto(s)
Humanos , Adolescente , Niño , Diabetes Mellitus Tipo 1/genética , Polimorfismo Genético , Receptor de Muerte Celular Programada 1/genética , Autoinmunidad , Anticuerpos/análisis , Diabetes Mellitus Tipo 1/inmunología , Frecuencia de los Genes , Marcadores Genéticos , GenotipoRESUMEN
Background: NADPH oxidase is a source of reactive oxygen species that may contribute to insulin resistance (IR). Aim: To assess the effect of a single oral dose of vanillin (a putative inhibitor of the enzyme) on IR in humans. Material and Methods: Using a crossover, random, double-blind design, eight lean and 10 obese males ingested 600 mg of vanillin or placebo followed by the ingestion of 75g of glucose. Serum/plasma glucose, free-fatty acids, insulin, glutathione, C reactive protein concentrations and red blood cell glutathione concentration were determined. Insulin resistance was estimated by the Matsuda index. Results: Under fasting conditions, obese individuals had higher glucose and insulin and lower red blood cell glutathione levels than their lean counterparts (p < 0.01). Serum free-fatty acids, total and oxidized plasma glutathione concentrations were similar in both groups. After glucose ingestion, obese individuals had a lower red blood cell total glutathione concentration and increased plasma oxidized glutathione concentration than their lean counterparts (p < 0.05). In addition, obese participants had a higher level of IR (p < 0.001) and impaired serum free-fatty acid suppression (p < 0.001) than their lean counterparts. Ingestion of vanillin did not modify any of these variables when compared with placebo in obese individuals. In lean volunteers a reduction in Matsuda index was detected when vanillin was administered, compared to placebo (4.3 +/- 0.6 and 3.6 +/- 0.6 respectively; p < 0.05). Conclusions: IR was ameliorated after vanillin ingestion among lean but not obese participants.
Asunto(s)
Humanos , Masculino , Adulto , Antioxidantes/administración & dosificación , Benzaldehídos/administración & dosificación , Obesidad , Resistencia a la Insulina/fisiología , Acetofenonas , Ácidos Grasos no Esterificados/análisis , Benzaldehídos/efectos adversos , Método Doble Ciego , Glucemia , Glutatión/análisis , Inflamación , NADPH Oxidasas , Estrés Oxidativo , Proteína C-Reactiva/análisisRESUMEN
Los pseudoaneurismas son más frecuentes hallarlos en los traumatismos arteriales en miembros inferiores. Se describe por la literatura internacional que hay una incidencia elevada en ortopedia con el uso de los fijadores en las fracturas de tibia yperoné. Se reporta un caso que sufrió una herida por arma blanca en cara externa de la pierna que estuvo sin diagnósticopor espacio de 18 meses, en todo este tiempo presentó aumento de volumen progresivo de la pierna y no padeció ningún síntomahasta su tratamiento. Se realizó la evacuación del gran hematoma con restauración de la arteria poplítea previa ligadura del pseudoaneurismas. La herida se cerró por segunda intención con el uso de azúcar de caña granulado. A los 29 días del postoperatorio el paciente estaba recuperado por completo (AU)
Pseudoaneurysms are more frequently found in arterial traumatisms in inferior members. According to international literaturethere is a risen incidence in orthopedics due to the use of fixers or nails in the tibia and fibula fractures. A case is reportedthat suffered a settle wound in the external face of the leg. It went without any diagnosis for 18 months. During this periodof time the leg presented and increase of progressive volume and the patient did not experience any symptom until his treatment.He underwent the evacuation of great haematoma and the restoration of the of the popliteal artery previous bond of the pseudoaneurysm. The wound closed up on second intention with the use of granulated sugar cane. After 29 days the patient was completely recovered (AU)
Asunto(s)
Humanos , Masculino , Persona de Mediana Edad , Vena Poplítea/fisiopatología , Aneurisma Falso/diagnóstico , Traumatismos de la Pierna/complicaciones , Fijación Interna de Fracturas/efectos adversos , Hematoma/cirugía , Técnicas de Cierre de Heridas , AzúcaresRESUMEN
Background: A genetic polymorphism called C1858T of protein tyrosine phosphatase, non-receptor type 22 (PTPN22) gene has been associated with autoimmune diseases Aim: To describe the association between two autoimmune diseases, namely type 1 diabetes (T1D) and celiac disease (CD)and tyrosine phosphatase gene polymorphisms (variant C1858T of PTPN22). Subjects and Methods: C1858T single-nucleotide polymorphism within the PTPN22 gene was genotyped in 209 patients with T1D, 43 celiac patients and 100 healthy controls. Results: CC gene frequency was 0.906 and 0.790 in CD patients and controls respectively ( p < 0.01). All analyzed groups had a low frequency of the TT genotype. Compared with the other study groups, patients with T1D had a low frequency of CC genotype (0.636). Also, in these patients, there was a non-significant association between CC genotype and islet cell IA-2 auto antibodies (p < 0.065). Among CD patients, CC genotype was significantly associated with anti-transglutaminase or anti endomysial antibodies (p < 0.03). Conclusions: These results confirm the association of the genetic variant C1858T of PTPN22 with CD. In contrast to published data, this association was not found in T1D patients.
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Humanos , Masculino , Adolescente , Adulto , Femenino , Preescolar , Niño , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/inmunología , Enfermedad Celíaca/genética , Enfermedad Celíaca/inmunología , /genética , Autoinmunidad/genética , Estudios de Casos y Controles , Chile , Frecuencia de los Genes , Marcadores Genéticos , Polimorfismo Genético , /inmunologíaRESUMEN
SUMMARY: Coil embolization of intracranial aneurysms is the first choice treatment in many centres worldwide. The ISAT study reported in favour of endovascular treatment even though coil embolization carries a higher risk of revascularization than surgical clipping. Bioactive coils boosting fibrosis within the aneurysm and neointimal production could counteract the tendency of embolized aneurysms to re-open. We reviewed our cohort in a retrospective study based on the following inclusion criteria: 1) Cerecyte coils (Micrus Endovascular, San Jose, Calif) were the only bioactive coils deployed. 2) Cerecyte coils were used in the first embolization procedure. Between July 2005 and December 2007 39 patients matched these inclusion criteria, 15 men and 24 women (average age 63.5 years) with 44 aneurysms. Treatment outcomes were: 30 aneurysms completed excluded from the circulation, 13 aneurysms almost completed excluded from the circulation, one incomplete aneurysm occlusion. Two aneurysms out of 44 recurred during follow-up (4.54%) and were re-embolized. The radio-opacity and conformational memory of the Cerecyte coils were satisfactory and they were easy to manoeuvre and detach.
RESUMEN
Existen numerosos indicadores de calidad de asistencia utilizados por organizaciones públicas, privadas y sin fines de lucro, que tienen por finalidad mejorar mejorar la práctica asistencial de maternidades. El objetivo de este trabajo fue comparar los estandares de dichos indicadores con los obtenidos en el Servicio de Maternidad del Hospital Clínico de la Universidad de Chile en el año 2004 y 2005.
Many public and private organizations use different obstetrical care quality indicators to improve medical care practice in maternity wards. The purpose of this study was to compare the available standards for those indicators, with the results obtained in the Obstetrics Service of the University of Chiles Clinical Hospital, for the 2004-2005 period.
Asunto(s)
Humanos , Femenino , Indicadores de Calidad de la Atención de Salud/estadística & datos numéricos , Obstetricia/estadística & datos numéricos , Parto Obstétrico/estadística & datos numéricos , Procedimientos Quirúrgicos Obstétricos/estadística & datos numéricos , Servicio de Ginecología y Obstetricia en Hospital/estadística & datos numéricos , ChileRESUMEN
Objetivos: Identificar y comprender los factores asociados a la generación de embarazo en adolescentes, desde la perspectiva de adolescentes escolares nuligestas. Material y Método: Estudio cualitativo, en mujeres entre 15 y 19 años, pertenecientes a dos establecimientos educacionales, con altos índices de embarazos, en la ciudad de Temuco, Chile. En Agosto y Septiembre de 2002 se realizaron cuatro grupos focales, constituido por 14 adolescentes nuligestas, identificándose factores individuales, familiares y sociales. Para el análisis se utilizó el programa ATLAS-ti 4,1 para Windows. Se trianguló por investigador y por disciplina, en la ejecución del estudio y análisis de los datos. Resultados: Aparecen como factores individuales relevantes que favorecen la generación del embarazo (FFGE): amor romántico, no uso de métodos anticonceptivos, baja autoestima, irresponsabilidad masculina y falta de conocimiento en sexualidad. Entre los factores familiares destacan: límite estrecho familiar y negligencia paterna. Entre las categorías individuales aparecen como factores que evitan el embarazo (FEE): capacidad reflexiva y proyecto de vida; en el ámbito familiar familia cuidadora y límites claros; en el ámbito social la categoría con mayor peso es sanción social. Conclusión: La visión de la adolescente nuligesta y el foco en el modelo multinivel usado en los grupos focales, aporta al problema del embarazo en adolescentes la posibilidad de establecer intervenciones a nivel de la adolescente, de la familia y del ámbito social, destacando como factores relevantes el amor romántico y los límites polares familiares. La capacidad de reflexión, y familia cuidadora son lo FEE relevantes.
Asunto(s)
Humanos , Femenino , Embarazo , Adolescente , Conducta del Adolescente , Embarazo en Adolescencia/estadística & datos numéricos , Embarazo en Adolescencia/prevención & control , Conocimientos, Actitudes y Práctica en Salud , Chile , Conducta Anticonceptiva , Factores Culturales , Relaciones Familiares , Investigación Cualitativa , Factores Sexuales , Conducta SexualRESUMEN
The sodium-vitamin C co-transporters SVCT1 and SVCT2 transport the reduced form of vitamin C, ascorbic acid. High expression of the SVCT2 has been demonstrated in adult neurons and choroid plexus cells by in situ hybridization. Additionally, embryonic mesencephalic dopaminergic neurons express the SVCT2 transporter. However, there have not been molecular and kinetic analyses addressing the expression of SVCTs in cortical embryonic neurons. In this work, we confirmed the expression of a SVCT2-like transporter in different regions of the fetal mouse brain and in primary cultures of neurons by RT-PCR. Kinetic analysis of the ascorbic acid uptake demonstrated the presence of two affinity constants, 103 microM and 8 microM. A K(m) of 103 microM corresponds to a similar affinity constant reported for SVCT2, while the K(m) of 8 microM might suggest the expression of a very high affinity transporter for ascorbic acid. Our uptake analyses also suggest that neurons take up dehydroascorbic acid, the oxidized form of vitamin C, through the glucose transporters. We consider that the early expression of SVCTs transporters in neurons is important in the uptake of vitamin C, an essential molecule for the fetal brain physiology. Vitamin C that is found at high concentration in fetal brain may function in preventing oxidative free radical damage, because antioxidant radical enzymes mature only late in the developing brain.
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Ácido Ascórbico/metabolismo , Proteínas Portadoras/metabolismo , Embrión de Mamíferos/metabolismo , Neuronas/metabolismo , Transportadores de Anión Orgánico Sodio-Dependiente , Proteínas/metabolismo , Simportadores , Animales , Proteínas Portadoras/genética , Células Cultivadas , Corteza Cerebral/citología , Citocalasina B/farmacología , Citocalasinas/farmacología , Inhibidores Enzimáticos/farmacología , Inmunohistoquímica , Cinética , Ratones , Ratones Endogámicos C57BL , Ouabaína/farmacología , Proteínas/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sodio/metabolismo , Transportadores de Sodio Acoplados a la Vitamina CRESUMEN
Glutathione deficiency is commonly associated with mitochondrial complex I dysfunction and loss of viability in neurones, but not in glia. In order to address the possible mechanism responsible for this cellular difference, the regulation of mitochondrial complex I expression by glutathione depletion was investigated in glial cells. Incubation of rat-cultured astrocytes and C6 glioma cells with the specific gamma-glutamylcysteine synthetase inhibitor L-buthionine-(S:,R:)-sulfoximine (L-BSO; 0.1-1 mM) decreased the total specific content of glutathione in a dose- and time-dependent fashion. Northern blot analyses revealed that glutathione deficiency caused by L-BSO (0.1 mM) was associated with a twofold enhancement in complex I regulatory subunit ND6 (mitochondrially encoded) mRNA expression after 24-72 h. This effect was accompanied by a twofold increase in complex-I activity at 72 h in L-BSO-treated cells, as compared with control cells, but complex II-III, complex IV and citrate synthase activities were unaltered. It is suggested that the oxidative stress caused by glutathione depletion in glial cells would up-regulate complex-I activity by enhancing the expression of the mitochondrially encoded regulatory subunit. These results could offer further insight into the different degree of cellular susceptibility observed in glial vs. neuronal cells against oxidative stress.
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Astrocitos/enzimología , Butionina Sulfoximina/farmacología , Regulación Enzimológica de la Expresión Génica , Glutatión/metabolismo , NADH NADPH Oxidorreductasas/genética , Neuroglía/enzimología , Animales , Animales Recién Nacidos , Células Cultivadas , Citrato (si)-Sintasa/genética , Complejo I de Transporte de Electrón , Complejo II de Transporte de Electrones , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Glioma , Complejos Multienzimáticos/genética , Oxidorreductasas/genética , Prosencéfalo/citología , Prosencéfalo/enzimología , Ratas , Ratas Wistar , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Succinato Deshidrogenasa/genética , Células Tumorales CultivadasRESUMEN
Se presenta la experiencia, en un estudio prospectivo, de 24 casos con lesiones traumáticas de colon, atendidos en el lapso de 2 años, en el Servicio de Emergencia del Hospital Clínico Viedma de Cochabamba, Bolivia. El 96 por ciento correspondió a pacientes del sexo masculino, siendo el promedio de edad de 25 años. El agente vulnerante más frecuente fue el arma blanca (62 por ciento) y el segmento colónico más comprometido, el colon transverso (45.8 por ciento). Lesiones asociadas se presentaron en el 62.5 por ciento de los casos, siendo el intestino delgado el más lesionado (87 por ciento). Para evaluar el grado de lesión del colon y de órganos asociados se utilizó el Indice de Trauma Abdominal Penetrante (PATI) y el Colon Injured Score (CIS) definido por Moore y cols. El 75 por ciento (18 pacientes) se clasificaron como CIS Asunto(s)
Humanos
, Femenino
, Masculino
, Adolescente
, Adulto
, Persona de Mediana Edad
, Colon/lesiones
, Colostomía
, Heridas Punzantes/cirugía
, Bolivia
, Complicaciones Posoperatorias
, Estudios Prospectivos
, Índices de Gravedad del Trauma
, Heridas Punzantes/complicaciones
, Heridas Punzantes/mortalidad
RESUMEN
The peptide containing the catalytic serine of beta-lactamase from Shigella flexneri was determined as V-D-E-R-F-P-M-M-S*-T-F-K. It is a local pathogenic strain which produces intestinal problems, especially in children. The highly purified enzyme was prepared by affinity chromatography in phenylboronic acid-agarose gels. The peptide was obtained by tryptic hydrolysis, with further purification by Bio-Gel P-4, Sephadex QAE-25 and Sephadex SP-25. The relevance of the serine, lysine and arginine residues was mainly shown by the loss of enzymatic activity after specific chemical modifications. Finally, this enzyme was classified as A, according to the similarity of this peptide with that of class A beta-lactamases such as R-TEM 1 and 2.
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Shigella flexneri/enzimología , beta-Lactamasas/química , Secuencia de Aminoácidos , Sitios de Unión/genética , Niño , Humanos , Modelos Moleculares , Fragmentos de Péptidos/química , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/metabolismo , Conformación Proteica , Shigella flexneri/genética , Shigella flexneri/patogenicidad , beta-Lactamasas/genética , beta-Lactamasas/metabolismoRESUMEN
A beta-lactamase (EC 3.5.2.6 penicillinase, penicillin amino beta-lactam-hydrolase) was purified from Shigella flexneri USCF-129 by an efficient two-stage procedure involving chromatography in Sephadex G-75 and HPLC on a C18-reverse phase column. The homogeneity of the purified enzyme was confirmed by capillary zone electrophoresis (CZE), HPLC electrospray mass spectrometry (LC-ESMS) and amino acid sequence analyses. The highly purified enzyme was a monomeric protein with a molecular mass of 28.903 +/- 2 Da, as determined by LC-ESMS. The amino acid sequence of the first 49 N-terminal residues of this beta-lactamase revealed 100% similarity with the mature forms of the plasmid coded Escherichia coli enzymes (plasmid pBR 322 and R6K) a TEM-type beta-lactamase.
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Shigella flexneri/enzimología , beta-Lactamasas/química , Secuencia de Aminoácidos , Aminoácidos/análisis , Cromatografía Líquida de Alta Presión , Espectrometría de Masas , Datos de Secuencia Molecular , Homología de Secuencia de AminoácidoRESUMEN
The genetic structure of humpback whale populations and subpopulation divisions is described by restriction fragment length analysis of the mitochondrial (mt) DNA from samples of 230 whales collected by biopsy darting in 11 seasonal habitats representing six subpopulations, or 'stocks', world-wide. The hierarchical structure of mtDNA haplotype diversity among population subdivisions is described using the analysis of molecular variance (AMOVA) procedure, the analysis of gene identity, and the genealogical relationship of haplotypes as constructed by parsimony analysis and distance clustering. These analyses revealed: (i) significant partitioning of world-wide genetic variation among oceanic populations, among subpopulations or 'stocks' within oceanic populations and among seasonal habitats within stocks; (ii) fixed categorical segregation of haplotypes on the south-eastern Alaska and central California feeding grounds of the North Pacific; (iii) support for the division of the North Pacific population into a central stock which feeds in Alaska and winters in Hawaii, and an eastern or 'American' stock which feeds along the coast of California and winters near Mexico; (iv) evidence of genetic heterogeneity within the Gulf of Maine feeding grounds and among the sampled feeding and breeding grounds of the western North Atlantic; and (v) support for the historical division between the Group IV (Western Australia) and Group V (eastern Australia, New Zealand and Tonga) stocks in the Southern Oceans. Overall, our results demonstrate a striking degree of genetic structure both within and between oceanic populations of humpback whales, despite the nearly unlimited migratory potential of this species. We suggest that the humpback whale is a suitable demographic and genetic model for the management of less tractable species of baleen whales and for the general study of gene flow among long-lived, mobile vertebrates in the marine ecosystem.
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ADN Mitocondrial/genética , Ballenas/genética , Animales , Femenino , Frecuencia de los Genes , Variación Genética , Haplotipos , Masculino , Océanos y Mares , Polimorfismo de Longitud del Fragmento de RestricciónRESUMEN
Hunting during the last 200 years reduced many populations of mysticete whales to near extinction. To evaluate potential genetic bottlenecks in these exploited populations, we examined mitochondrial DNA control region sequences from 90 individual humpback whales (Megaptera novaeangliae) representing six subpopulations in three ocean basins. Comparisons of relative nucleotide and nucleotype diversity reveal an abundance of genetic variation in all but one of the oceanic subpopulations. Phylogenetic reconstruction of nucleotypes and analysis of maternal gene flow show that current genetic variation is not due to postexploitation migration between oceans but is a relic of past population variability. Calibration of the rate of control region evolution across three families of whales suggests that existing humpback whale lineages are of ancient origin. Preservation of preexploitation variation in humpback whales may be attributed to their long life-span and overlapping generations and to an effective, though perhaps not timely, international prohibition against hunting.
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Evolución Biológica , ADN Mitocondrial/genética , Variación Genética , Ballenas/genética , Animales , Océano Atlántico , Secuencia de Bases , Datos de Secuencia Molecular , Oligodesoxirribonucleótidos , Océano Pacífico , Filogenia , Reacción en Cadena de la PolimerasaRESUMEN
The effect of a powerful inhibitor, BRL 42715, on beta-lactamase from Shigella flexneri UCSF-129, to overcome the problem of shigellosis and its resistance to ampicillin, was studied. The I50 was determined for BRL 42715 [C6-(N1-methyl-1,2,3 triazolylmethylene)penem] as 0.0049 microgram/ml being 20-fold lower than the best inhibitor, 6-beta-iodopenicillanic acid, previously reported. The MIC fell from 2,048 to 2 micrograms/ml in the presence of 1 microgram/ml of BRL 42715. The synergism of the ampicillin plus this inhibitor lasted for 9 h. BRL 42715 is an irreversible inhibitor, according to the dialysis results, and a substrate analogue.
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Antibacterianos/farmacología , Lactamas , Shigella flexneri/enzimología , Inhibidores de beta-Lactamasas , beta-Lactamas , Resistencia a la Ampicilina , Pruebas de Sensibilidad Microbiana , beta-Lactamasas/metabolismoRESUMEN
Se aborda el trabajo comunitario como estrategia de impacto en la estructura de los servicios de salud, con el fin de modificar su funcionamiento, se definela importancia de los trabajadores de la salud en la comunidad en contraposiciòn al trabajo tradicional respectivo, individual y sin proyeccòn y la participación de la poblacion en la definición de objetivos y consecución de logros.
Asunto(s)
Personal de Salud , Servicios de Salud Comunitaria , Participación de la ComunidadRESUMEN
We have designed and synthesized several cyclic disulfide-containing peptide analogues of dynorphin A (Dyn A) which are conformationally constrained in the putative "address" segment of the opioid ligand. Several of these Dyn A analogues exhibit unexpected selectivities for the kappa and mu opioid receptors(s) of the central vs peripheral nervous systems. Thus, incorporation of conformational constraint in the putative "address" segment of Dyn A analogues has resulted in the kappa/mu opioid receptor ligands [Cys5,Cys11]Dyn A1-11-NH2 (1) and [Cys5,Cys11,D-Ala8]Dyn A1-11-NH2 (2), which possess high kappa and mu opioid receptor affinities centrally (guinea pig brain, GPB), but only weak activity at peripheral kappa and mu opioid receptors (guinea pig ileum, GPI). On the other hand, [Cys8,Cys13]Dyn A1-13-NH2 and [D-Cys8,D-Cys13]Dyn A1-13-NH2 (5) display high kappa potencies and selectivities at the peripheral (GPI) but not at the central (GPB) kappa opioid receptor. The lack of correlation between the pharmacological profiles observed in smooth muscle and in the brain binding assays suggests the existence of different subtypes of the kappa and mu opioid receptors in the brain and peripheral nervous systems.