Estradiol modulates visceral hyperalgesia by increasing thoracolumbar spinal GluN2B subunit activity in female rats.

BACKGROUND: We previously reported estrogen modulates spinal N-methyl-d-aspartate (NMDA) receptor processing of colorectal pain through changes in spinal GluN1 subunit phosphorylation/expression. The purpose of this study was to investigate whether spinal GluN2B containing NMDA receptors are involved in estrogen modulation of visceral pain processing. METHODS: Behavioral, molecular, and immunocytochemical techniques were used to determine spinal GluN2B expression/phosphorylation and function 48 h following subcutaneous injection of estradiol (E2) or vehicle (safflower oil, Saff oil) in ovariectomized rats in the absence or presence of colonic inflammation induced by mustard oil. KEY RESULTS: E2 increased the magnitude of the visceromotor response (VMR) to colorectal distention compared to Saff oil in non-inflamed rats. Intrathecal injection of the GluN2B subunit antagonist, Ro 25-6981, had no effect on the VMR in non-inflamed E2 or Saff oil rats. Colonic inflammation induced visceral hyperalgesia in E2, but not Saff oil rats. Visceral hyperalgesia in E2 rats was blocked by intrathecal GluN2B subunit selective antagonists. In inflamed rats, E2 increased GluN2B protein and gene expression in the thoracolumbar (TL), but not lumbosacral (LS), dorsal spinal cord. Immunocytochemical labeling showed a significant increase in GluN2B subunit in the superficial dorsal horn of E2 rats compared to Saff oil rats. CONCLUSIONS & INFERENCES: These data support the hypothesis that estrogen increases spinal processing of colonic inflammation-induced visceral hyperalgesia by increasing NMDA receptor activity. Specifically, an increase in the activity of GluN2B containing NMDA receptors in the TL spinal cord by estrogen underlies visceral hypersensitivity in the presence of colonic inflammation.

Colonization and risk factors for Brachyspira aalborgi and Brachyspira pilosicoli in humans and dogs on tea estates in Assam, India.

The prevalence of colonization with the anaerobic intestinal spirochaetes Brachyspira aalborgi and Brachyspira pilosicoli was investigated in humans (n = 316) and dogs (n = 101) living on three tea estates in Assam, India. Colonization was detected using PCR on DNA from faeces. Nineteen (6%) human faecal samples contained B. aalborgi DNA, 80 (25.3%) contained B. pilosicoli DNA, and 10 (3.2%) contained DNA from both species. One canine sample contained DNA from B. pilosicoli. Significant factors for B. aalborgi colonization in logistic regression were: infection of family members with B. aalborgi (P < 0.001), being a resident of Balipara (P = 0.03), and use of water treatment (P = 0.03). For B. pilosicoli, significant factors were: other family members being positive for B. pilosicoli (P < 0.001), water obtained from a well (P = 0.006), water treatment (P = 0.03), and not having visited a doctor in the previous 12 months (P = 0.03).

Distribution of natural thorium in the tissues of a whole body.

The distribution of thorium in the tissues of a whole body donor to the United States Transuranium and Uranium Registries is described. This case, identified by the USTUR as Case 0212, had two documented intakes of plutonium and americium from occupational accidents while employed at Hanford but no known occupational exposure to thorium. Concentrations of 239+240Pu, 241Am, and 232Th in the tissues are compared and the distribution of these isotopes in this case is evaluated. The distribution data for 232Th are compared to those from previous studies of thorium in human tissues resulting from environmental exposure and to an individual exposed to Thorotrast (colloidal ThO2) in a medical diagnostic procedure. The 232Th distribution data from this work are also compared against ICRP 30 and ICRP 69 models for the behaviour of thorium in the human body.