Traumatic brain injury and cognitive impairment in men who are homeless.

PURPOSE: To examine cognitive performance among a sample of men in a residential unit of an urban homeless shelter and to compare cognitive performance between those with and without a history of traumatic brain injury (TBI). METHODS: An exploratory, quantitative study of participants recruited through convenience sampling. Participants were screened for TBI using the Brain Injury Screening Questionnaire, and cognitive function using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Data were analyzed to examine associations between TBI status and cognitive performance. RESULTS: Thirty-four participants were recruited for the study: n = 12 with a positive and n = 22 with a negative screen for TBI. Both groups performed below norms in all cognitive domains measured by the RBANS. Those with a positive screen for TBI performed significantly worse on attention tasks than those with a negative screen for TBI (p = 0.026). RBANS scores were not associated with either mental health or substance abuse status. CONCLUSIONS: A history of TBI was associated with generally poorer cognitive performance in the study sample. An improved awareness of TBI and cognitive dysfunction among service providers and routine TBI screening could improve treatment and service delivery for this population.

Detection of non-host viable contaminants in Pichia pastoris cultures and fermentation broths.

The ability to detect viable contaminants in cultures propagated from the original host-expression system ensures that the integrity and purity of seed banks, fermentation broths, and ultimately the final product are continually controlled and maintained. The method developed to detect such agents must be selective for a broad spectrum of microbes, which may be present at very low levels, while discriminating from the host organisms. Although Pichia pastoris strains are frequently used as cell lines for the expression of heterologous proteins, a method that is specific for monitoring culture purity has yet to be reported for this type of organism. An assay that is capable of recovering contaminating bacteria, fungi, and closely related yeast from cultures of P. pastoris at parts per million detection limits is described here.