University of Texas Medical Branch

About: University of Texas Medical Branch is a education organization based out in Galveston, Texas, United States. It is known for research contribution in the topics: Population & Virus. The organization has 22033 authors who have published 38268 publications receiving 1517502 citations. The organization is also known as: The University of Texas Medical Branch at Galveston & UTMB.

Replication by human DNA polymerase-ι occurs by Hoogsteen base-pairing

Abstract: Almost all DNA polymerases show a strong preference for incorporating the nucleotide that forms the correct Watson–Crick base pair with the template base. In addition, the catalytic efficiencies with which any given polymerase forms the four possible correct base pairs are roughly the same. Human DNA polymerase-ι (hPolι), a member of the Y family of DNA polymerases, is an exception to these rules. hPolι incorporates the correct nucleotide opposite a template adenine with a several hundred to several thousand fold greater efficiency than it incorporates the correct nucleotide opposite a template thymine, whereas its efficiency for correct nucleotide incorporation opposite a template guanine or cytosine is intermediate between these two extremes1,2,3,4,5. Here we present the crystal structure of hPolι bound to a template primer and an incoming nucleotide. The structure reveals a polymerase that is ‘specialized’ for Hoogsteen base-pairing, whereby the templating base is driven to the syn conformation. Hoogsteen base-pairing offers a basis for the varied efficiencies and fidelities of hPolι opposite different template bases, and it provides an elegant mechanism for promoting replication through minor-groove purine adducts that interfere with replication.

Chronic central pain after spinal cord injury.

Abstract: Spinal cord injury (SCI) frequently results in dysesthesias that have remained refractory to clinical treatments despite a variety of interventions The failure of therapeutic strategies to treat dysesthesias after SCI is due to the lack of attention given to mechanisms that elicit chronic pain following SCI An overview of the literature with respect to the development of chronic pain in the SCI patient population will be given In addition, a mammalian model of chronic central pain following spinal cord trauma will be presented The model is characterized by the development of mechanical and thermal allodynia, as demonstrated by measuring the thresholds of accepted nociceptive tests, the paw withdrawal responses accompanied by changes in behavior consistent with the experience of noxious stimuli In addition, vocalization responses that are accompanied by postural and behavioral changes consistent with the receipt of a noxious stimulus and involving supraspinal pathways are measured Locomotor function was also tested and scored using the Basso, Beattie, and Bresnahan (BBB) open field test scale Our data indicate that somatosensory thresholds for both mechanical and thermal stimuli that elicit paw withdrawal (flexor reflex) or vocalizations, accompanied by complex changes in behavior, are significantly different following SCI These changes represent the development of mechanical and thermal allodynia To determine the underlying mechanism for the altered sensory responses, we used electrophysiological techniques to determine if nociceptive dorsal horn neurons demonstrated increased excitability to peripheral stimulation as evidenced by increased responses to natural somatosensory stimuli The data presented support the development of central sensitization of dorsal horn neurons after spinal cord hemisection This provides a mechanism for the development of mechanical and thermal allodynia after SCI Hypotheses that account for the development of the central pain state after SCI, as well as therapeutic interventions to ameliorate the pain state, are discussed

Emerging infections in burns.

Abstract: Background: Patients who suffer severe burns are at higher risk for local and systemic infections. In recent years, emerging resistant pathogens have forced burn care providers world wide to search for alternative forms of treatment. Multidrug-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter spp., and various fungal strains have been the major contributors to the increase in morbidity and mortality rates. Multi-drug-resistant S. aureus remains the major cause of gram-positive burn wound infections world wide. Treatment strategies include rigorous isolation protocols and new types of antibiotics where necessary. Methods: We reviewed 398 severely burned patients (burns >40% total body surface area [TBSA]) admitted to our hospital between 2000 and 2006. Patients who did not contract multi-drug-resistant gram-negative organisms during their hospital course and received our standard antibiotic regimen—vancomycin and piperacillin/tazobactam—served as controls (piperacillin/tazobac...

Rickettsia bellii and Rickettsia amblyommii in Amblyomma ticks from the State of Rondônia, Western Amazon, Brazil.

Abstract: This study evaluates the rickettsial presence in Amblyomma ticks from eight areas of the Amazon forest in Rondonia, Brazil. The following tick species (number in parentheses) were examined: Amblyomma ovale Koch (121), Amblyomma cajennense (F.) (41), Amblyomma naponense (Packard) (36), Amblyomma scalpturatum Neumann (35), Amblyomma oblongoguttatum Koch (30), Amblyomma incisum Neumann (27), Amblyomma rotundatum Koch (16), Amblyomma coelebs Neumann (10), and Amblyomma humerale Koch (6). Ticks were examined individually or in pools (2-10 ticks) by polymerase chain reaction (PCR) targeting the gltA gene. The PCR-determined minimal infection rate for each tick species was A. ovale 28%, A. cajennense 27%, A. naponense 0%, A. scalpturatum 11%, A. oblongoguttatum 3%, A. incisum 0%, A. rotundatum 87%, A. coelebs 10%, and A. humerale 50%. Partial sequences of the gltA gene of Rickettsia from A. ovale, A. scalpturatum, A. oblongoguttatum, A. rotundatum, and A. humerale were 99.9% (349/350) identical to Rickettsia bellii. DNA sequences of PCR products from A. cajennense and A. coelebs were 100% (350/350) identical to Rickettsia amblyommii. R. bellii organisms were isolated in Vero cells from A. scalpturatum, A. ovale, A. rotundatum, and A. oblongoguttatum, but only one of the isolates, cultured from A. scalpturatum, was established in continuous cell culture passage. R. amblyommii was isolated from A. cajennense and was successfully established in continuous passage in cell culture. R. amblyommii infection of Vero cells was analyzed by transmission electron microscopy. This study adds South America to the known geographic distribution of R. amblyommii and reports rickettsiae in six Amblyomma species for the first time.