Experimental manipulation of population-level MHC diversity controls pathogen virulence evolution in Mus musculus.

The virulence levels attained by serial passage of pathogens through similar host genotypes are much higher than observed in natural systems; however, it is unknown what keeps natural virulence levels below these empirically demonstrated maximum levels. One hypothesis suggests that host diversity impedes pathogen virulence, because adaptation to one host genotype carries trade-offs in the ability to replicate and cause disease in other host genotypes. To test this hypothesis, with the simplest level of population diversity within the loci of the major histocompatibility complex (MHC), we serially passaged Friend virus complex (FVC) through two rounds, in hosts with either the same MHC genotypes (pure passage) or hosts with different MHC genotypes (alternated passage). Alternated passages showed a significant overall reduction in viral titre (31%) and virulence (54%) when compared to pure passages. Furthermore, a resistant host genotype initially dominated any effects due to MHC diversity; however, when FVC was allowed to adapt to the resistant host genotype, predicted MHC effects emerged; that is, alternated lines show reduced virulence. These data indicate serial exposure to diverse MHC genotypes is an impediment to pathogen adaptation, suggesting genetic variation at MHC loci is important for limiting virulence in a rapidly evolving pathogen and supports negative frequency-dependent selection as a force maintaining MHC diversity in host populations.

An unusual case of primary spontaneous tension pneumothorax in a jamaican female.

Spontaneous pneumothorax is a well-recognized entity with a classical presentation of acute onset chest pain and shortness of breath. It may be complicated by the development of a tension pneumothorax or a haemopneumothorax. We report an interesting case of a spontaneous tension haemopneumothorax which presented atypically and was diagnosed on computed tomography (CT) scan of the chest. The clinical and pathophysiological characteristics and treatment of this unusual entity is discussed.

Diabetic mastopathy: an uncommon complication of diabetes mellitus.

Introduction. Whilst most consequences of diabetes mellitus are well recognized, breast-related complications remain obscure. The term diabetic mastopathy (DMP) attempts to describe the breast-related consequences of diabetes. Methods. We report the clinicopathologic findings in a patient with DMP and review the literature on this uncommon entity. Results. A 33-year-old woman with type 1 diabetes had excision biopsy of a 2 cm breast lump. Histopathologic evaluation revealed classic features of DMP: parenchymal fibrosis; keloid-like hyalinization of interlobular stroma; adipose tissue entrapment; lobular compression; dense chronic inflammatory cell infiltration; and lymphoid follicle formation. Conclusion. Clinicians should be aware of DMP as a differential for breast disease in women with uncontrolled diabetes.

Experimental viral evolution reveals major histocompatibility complex polymorphisms as the primary host factors controlling pathogen adaptation and virulence.

Using an experimental evolution approach, we recently demonstrated that the mouse-specific pathogen Friend virus (FV) complex adapted to specific major histocompatibility complex (MHC) genotypes, which resulted in fitness tradeoffs when viruses were exposed to hosts possessing novel MHC polymorphisms. Here we report the analysis of patterns of pathogen adaptation and virulence evolution from viruses adapting to one of three hosts that differ across the entire genome (A/WySn, DBA/2J and BALB/c). We found that serial passage of FV complex through these mouse genotypes resulted in significant increases in pathogen fitness (156-fold) and virulence (11-fold). Adaptive responses by post-passage viruses also resulted in host-genotype-specific patterns of adaptation. To evaluate the relative importance of MHC versus non-MHC polymorphisms as factors influencing pathogen adaptation and virulence, we compared the magnitude of fitness tradeoffs incurred by post-passage viruses when infecting hosts possessing either novel MHC polymorphisms alone or hosts possessing novel MHC and non-MHC polymorphisms. MHC polymorphisms alone accounted for 71% and 83% of the total observed reductions in viral fitness and virulence in unfamiliar host genotypes, respectively. Strikingly, these data suggest that genetic polymorphisms within the MHC, a gene region representing only -0.1% of the genome, are major host factors influencing pathogen adaptation and virulence evolution.

Degenerative disc disease of the lumbar spine on MRI / La enfermedad degenerativa del disco de la espina lumbar en IRM

A retrospective analysis was done of all patients referred for MRI of the lumbar spine at the University Hospital of the West Indies, Kingston, Jamaica, during the three-year period January 1, 2005 and December 31, 2007. Data were collected to determine patients' age, gender, weight and the presence or absence of degenerative disc disease (DDD). The patients' presenting symptoms were not evaluated. There were 362 patients examined: 154 males, 204 females and four uncharacterized, aged between 8 and 87 (mean age = 50.45) years. Degenerative Disc Disease (DDD), was found in 283 (78.2%) patients: 121 males, 159 females and three unidentified, with a total of 669 degenerate discs. L 4/5 and L 5/S 1 were most frequently affected accounting for 31.2% and 30.6% of degenerate discs respectively. Patients with DDD were significantly heavier and significantly older than patients without disc disease. Gender was not predictive of DDD in general nor of involvement of any particular disc though a marginally significant tendency was found for males to more frequently have DDD at L1/2 and L5/S1. CONCLUSION: Degenerative disc disease of the lumbar spine occurred more frequently in older and heavier patients. Gender did not affect the presence or the extent of the disease; compared to females, males showed a marginally increased tendency to have DDD at L1/2 and L5/S1.

Se realizó un análisis retrospectivo de todos los pacientes remitidos para IRM de la espina lumbar en el Hospital Universitario de West Indies, Kingston, Jamaica, durante el periodo de tres años comprendido de enero 1 de 2005 a diciembre 31 de 2007. Se recogieron datos de los pacientes a fin de determinar su edad, género, peso y la presencia o ausencia de la enfermedad degenerativa del disco (EDD). Los síntomas presentes en los pacientes no fueron evaluados. Se examinaron 362 pacientes: 154 varones, 204 hembras y cuatro no caracterizados, de edades entre 8 y 87 (edad promedio = 50.45) años. La enfermedad degenerativa del disco (EDD) se halló en 283 (78.2%) pacientes: 121 varones, 159 hembras y tres no identificados, para un total de 669 discos degenerados. L 4 /5 y L 5 / S 1 fueron los más frecuentemente afectados, representando el 31.2% y 30.6% de los discos degenerados, respectivamente. Los pacientes con EDD tenían significativamente más peso y mayor edad que aquellos sin la enfermedad del disco. El género no era en general predictivo de EDD ni de involucración de disco alguno en particular, si bien se halló marginalmente una tendencia significativa a una mayor frecuencia en la manifestación de EDD en L1 / 2 y L5 / S1 entre los varones CONCLUSIÓN: La enfermedad degenerativa del disco de la espina lumbar se presentó en pacientes de mayor edad y mayor peso. El género no afectó la presencia o la magnitud de la enfermedad. Sin embargo, en comparación con las hembras, los varones mostraron una tendencia marginalmente mayor a presentar EDD en L1/2 y L5/S1.

Degenerative disc disease of the lumbar spine on MRI.

UNLABELLED: A retrospective analysis was done of all patients referred for MRI of the lumbar spine at the University Hospital of the West Indies, Kingston, Jamaica, during the three-year period January 1, 2005 and December 31, 2007. Data were collected to determine patients 'age, gender, weight and the presence or absence of degenerative disc disease (DDD). The patients' presenting symptoms were not evaluated. There were 362 patients examined: 154 males, 204 females and four uncharacterized, aged between 8 and 87 (mean age = 50.45) years. Degenerative Disc Disease (DDD), was found in 283 (78.2%) patients: 121 males, 159 females and three unidentified, with a total of 669 degenerate discs. L 4/5 and L 5/S 1 were most frequently affected accounting for 31.2% and 30.6% of degenerate discs respectively. Patients with DDD were significantly heavier and significantly older than patients without disc disease. Gender was not predictive of DDD in general nor of involvement of any particular disc though a marginally significant tendency was found for males to more frequently have DDD at L1/2 and L5/S1. CONCLUSION: Degenerative disc disease of the lumbar spine occurred more frequently in older and heavier patients. Gender did not affect the presence or the extent of the disease; compared to females, males showed a marginally increased tendency to have DDD at L1/2 and L5/S1.

An assessment of clinical predictors of intracranial head injury identified by computed Tomography scan / Evaluación de los predictores clínicos de la lesión cefálica intracraneal identificada mediante tomografía axial computarizada

A prospective study was done during a six-month period on 104 consecutive patients who were seen at the Accident and Emergency (A&E) Department of the UHWI and referred for CT scans of the head within 24 hours of sustaining head injuries. There were 74 (71.1%) males and 30 (28.8%) females. The mean age for females was 40.6 years and 32.4 years for males. Patients were clinically assessed for the presence or absence of vomiting, amnesia, loss of consciousness. bleeding of ear, nose and throat (ENT) and Glasgow Coma score (GCS).Negative predictive values were calculated for each parameter individually as well as the combination of all five. The absence of vomiting, amnesia, "loss of consciousness" (LOC ) or ENT bleed had negative predictive values of 68%, 73%, 76% and 61.6% respectively. An assessment of Glasgow Coma Scale (GCS) of 15 had a 77.5% negative predictive value. When the history was indeterminate, the negative predictive values were 19%, 25%, 60% and 18% respectively for vomiting, amnesia, LOC and ENT bleed.When all four clinical indicators were absent in the history and examination and the GCS score 15, the negative predictive value for intracranial injury was 89.4%. In summary, the clinical indicators reviewed, alone or in combination, cannot exclude the presence of intracranial injury.

Un estudio prospectivo fue realizado por un período de seis meses, durante el cual 104 pacientes consecutivos fueron atendidos en el Departamento de Accidente y Emergencia (A&E) del HUWI, y referidos para TAC de la cabeza dentro de las 24 horas de haber sufrido lesiones cefálicas. Hubo 74 varones (71.1%) y 30 (28.8%) hembras. La edad promedio de las hembras fue 40.6 años, y la de los varones 32.4. Los pacientes fueron evaluados clínicamente para detectar la presencia o ausencia de vómitos, amnesia, pérdida de la conciencia, sangramiento de garganta, nariz y oído (G.N.O.) y la Escala de Coma de Glasgow.Se calcularon los valores predictivos negativos para cada parámetro individualmente, así como la combinación de los cinco. La ausencia de vómitos, amnesia, "pérdida de la conciencia" (PDC) o sangramiento G.N.O. tuvieron valores predictivos negativos de 68%,73%,76%, y 61.6% respectivamente. Una evaluación de la Escala de Coma de Glasgow (GCS) de 15 tuvo un 77.5% de valor predictivo negativo. Cuando la historia fue indeterminada, los valores predictivos negativos fueron 19%, 25%, 60% y 18% respectivamente para el vómito, la amnesia, la PDC, y el sangramiento G.N.O.Cuando los cuatro indicadores clínicos estuvieron ausentes en la historia y el examen y la puntuación de CGS, el valor predictivo negativo de la lesión intracraneal fue 89.4%. En resumen, los indicadores clínicos examinados - solos o en combinación, no pueden excluir la presencia de la lesión intracraneal.

An assessment of clinical predictors of intracranial head injury identified by computed tomography scan.

A prospective study was done during a six-month period on 104 consecutive patients who were seen at the Accident and Emergency (A&E) Department of the UHWI and referred for CT scans of the head within 24 hours of sustaining head injuries. There were 74 (71.1%) males and 30 (28.8%) females. The mean age for females was 40.6 years and 32.4 years for males. Patients were clinically assessed for the presence or absence of vomiting, amnesia, loss of consciousness, bleeding of ear, nose and throat (ENT) and Glasgow Coma score (GCS). Negative predictive values were calculated for each parameter individually as well as the combination of all five. The absence of vomiting, amnesia, "loss of consciousness" (LOC) or ENT bleed had negative predictive values of 68%, 73%, 76% and 61.6% respectively. An assessment of Glasgow Coma Scale (GCS) of 15 had a 77.5% negative predictive value. When the history was indeterminate, the negative predictive values were 19%, 25%, 60% and 18% respectively for vomiting, amnesia, LOC and ENT bleed. When all four clinical indicators were absent in the history and examination and the GCS score 15, the negative predictive value for intracranial injury was 89.4%. In summary, the clinical indicators reviewed, alone or in combination, cannot exclude the presence of intracranial injury.