Child Health and Pediatric Education in Oklahoma

The University of Oklahoma Medical Center has a comprehensive program of pediatric training, research and patient care. Establishment of the Oklahoma Health Center and its Children's Medical Center on the University campus will provide expanded opportunities for training and research in cooperation with other organizations concerned with child health and development.     

Quantitative real time PCR assays for the detection of Leishmania (Viannia) braziliensis in animals and humans

American cutaneous leishmaniasis (ACL) caused by Leishmania (Viannia) braziliensis is a neglected disease of humans in the New World that may also cause irreversible skin and eventually mucocutaneous lesions. This parasite can also infect dogs and represents a diagnostic challenge for veterinarians. Methods currently available for the diagnosis of ACL have a low sensitivity and may be time-consuming, representing a limit for treatment expedition of ACL. Quantitative real time PCR assays (qPCR) for the detection of L. (V.) braziliensis in canine blood samples were developed herein, and the detection limit and specificity of different molecular targets (kDNA and rDNA) evaluated. Of the protocols assessed, two qPCR assays, one targeting the kDNA and other the SSU rDNA of L. (V.) braziliensis, performed better, with detection limits of 100 fg and 10 pg, respectively. These assays were also used to test skin samples from humans with suspected ACL. The results indicate that the qPCR protocols developed represent an advance for the diagnosis of ACL in dogs and humans from this region, and provide a rapid and non-invasive diagnosis of the infection by L. (V.) braziliensis. Considering the quantitative nature of the assays, they will also be useful for monitoring treatment efficacy and preventing relapses in human patients in Brazil, although further studies are needed to critically evaluate the specificity of the qPCRs for their capacity to distinguish different Leishmania species and subspecies (represented by zymodemes) in other countries. Finally, molecular assays established may represent new tools for future basic and applied research focused on species identification, host–parasite associations, and infection dynamics in host and vector populations.     

Testicular function and pelage color have different critical daylengths in the Djungarian hamster, Phodopus sungorus sungorus

Testicular function and pelage color are regulated by photoperiod in the Djungarian hamster. To investigate the critical daylengths of these functions, adult male hamsters were exposed to one of four photoperiods: 16 h of light, 8 h of darkness (16L:8D), 14L:10D, 12L:12D, or 10L:14D. 10L:14D and 12L:12D induced the winter molt and testicular regression, in contrast to 14L:10D which induced only the latter response, and 16L:8D which maintained the summer pelage and large testes. Melatonin injections administered 4, 2, or 0 h before lights-off to hamsters exposed to 16L:8D mimicked the effects in hamsters exposed to 10:14D, 12L:12D or 14L:10D, respectively, on pelage color and testicular weight. Based on previous observations, the elevated circulating melatonin levels resulting from these injections were expected to extend the endogenous melatonin peak. Thus, this finding suggests that the duration of circadian melatonin elevation is the critical parameter determining its effect not only on the gonads, but also on the pelage. Since 14L:10D induced testicular regression but not the winter molt, this study also investigated whether circulating FSH levels, known to affect testicular function, and PRL levels, which have been shown to affect pelage color, might be affected differently by 14L:10D. Both FSH and PRL levels were found to be suppressed in 14L:10D hamsters compared to those in 16L:8D hamsters, although the interval between the initial decrease and eventual recovery was less than that in 10L:14D hamsters. Thus, the differential responses of the pelage and gonads to 14L:10D do not appear to be based on selective suppression of FSH in this photoperiod. However, different responses to 14L:10D compared to 10L:14D may be related to the shorter period of suppression of both PRL and FSH by the 14L:10D daylengths.     

Differentiation of fetal pig endocrine cells after allografting into the thymus gland

BACKGROUND: The thymus of large animals, such as the pig, is thought to be an appropriate site for transplanting adult islets, which contain numerous beta cells, for the purpose of reversing diabetes. Whether fetal islet-like cell clusters (ICCs), which contain few beta cells, will develop at this site, so that adequate amounts of insulin can be produced, is unknown. METHODS: Between 15,000 and 40,000 ICCs were injected into the thymus gland of six juvenile immunosuppressed pigs, and the animals were killed up to 30 days later. The graft was then examined histologically and comparisons made with untransplanted ICCs and those grafted into the omentum of immunosuppressed pigs. RESULTS: At transplantation, the percentage of cells in the ICCs containing insulin, glucagon, somatostatin, or pancreatic polypeptide was 9+/-1%, 13+/-2%, 9+/-1%, and 3+/-1% respectively. Within 9-30 days of transplantation into the thymus, the percentage of all endocrine cells increased, insulin to 41+/-3%, glucagon to 43+/-6%, somatostatin to 26+/-4%, and pancreatic polypeptide to 9+/-3%. There was co-localization of more than one hormone in some cells. Omental grafts contained a similar percentage of insulin and glucagon-containing cells, but significantly fewer somatostatin and pancreatic polypeptide-containing cells. CONCLUSIONS: Endocrine cells from the fetal pig pancreas will differentiate when transplanted into the thymus gland of the pig, making this a suitable site for grafting ICCs to test their ability to normalize blood glucose levels of diabetic recipients.