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P Nag

Publications and source records attributed to P Nag.

6 recordsLinked to original sources
PubMed2006

Fentanyl-augmented MRCP.

BACKGROUND: Drugs such as secretin and morphine have been used to augment the visualization of magnetic resonance cholangiopancreatography (MRCP). This study investigated the effectiveness of intravenous administration of a synthetic opioid, fentanyl, in improving the MRCP image quality. METHODS: Thirty consecutive patients with a provisional diagnosis of benign biliary and/or pancreatic disease underwent MRCP. Coronal single-shot fast spin-echo heavily T2-weighted dynamic MRCP images were generated before and at every minute for 10 min after intravenous administration of fentanyl citrate at a dose of 1.0 mug/kg. Pre- and postinjection images were compared and analyzed qualitatively and quantitatively. RESULTS: Qualitatively, visualization of intrahepatic bile ducts, common bile duct, and main pancreatic duct improved after fentanyl injection in five (16%), 11 (37%), and 19 (63%) patients, respectively. The pancreatobiliary junction and common channel were visualized better after fentanyl injection in eight of the 18 patients (44%). Quantitatively, signal intensity and diameters of the intrahepatic ducts, common bile duct, and main pancreatic duct measured at corresponding points on pre- and postinjection images showed an increase above preinjection values in 28 (93%), 27 (90%), and 21 (70%) and in 18 (60%), 26 (86%), and 22 (73%), respectively, and these changes were highly significant at all sites (p < 0.001). CONCLUSIONS: Intravenous administration of fentanyl before MRCP improves qualitative and quantitative visualization of the ductal system anatomy that may be of value in clinical diagnosis and management.

Adolescent↗
PubMed2000

Androgenic regulation of steroid hormone receptor mRNAs in the brain of whiptail lizards.

Sex and species differences in androgenic regulation of steroid hormone receptor mRNAs were examined in the diencephalon of two species of whiptail lizards: Cnemidophorus inornatus is a sexual species and the direct evolutionary ancestor to Cnemidophorus uniparens, an all-female parthenogenetic species. Lizards were gonadectomized and treated with different doses of either aromatizable testosterone or nonaromatizable dihydrotestosterone. The relative abundances of androgen-, oestrogen-, and progesterone-receptor mRNAs were compared in various nuclei following in situ hybridization with homologous riboprobes. A diversity of patterns in androgenic regulation was observed, with effects differing according to brain region, the steroid-receptor mRNA being considered and, in some cases, between androgens. In the ancestral sexual species, intact males had lower androgen-receptor mRNA abundances than castrated, blank-implanted males in the medial preoptic area. Testosterone significantly decreased androgen-receptor mRNA abundance in the medial preoptic area of castrated males. Males had higher androgen-receptor mRNA levels in the preoptic area than females generally and neither the sexual or parthenogenetic females showed a decrease in androgen-receptor mRNA with androgen treatment. Both testosterone and dihydrotestosterone increased oestrogen-receptor mRNA abundance in the ventromedial hypothalamus of C. inornatus, but no sex differences in this effect were observed. Gonadectomy decreased, whereas androgen treatment increased, progesterone-receptor mRNA abundance in the ventromedial hypothalamus. There was a sex difference in this response to androgen in the sexual species, with males having greater amounts than females in this brain area. The parthenogenetic species exhibited a similar pattern to females of the sexual species, but the levels were higher overall, possibly because Cnemidophorus uniparens is triploid. The periventricular preoptic area showed a different pattern, with testosterone treatment increasing progesterone-receptor mRNA abundance in both sexes of the sexual species and in the parthenogenetic species, while dihydrotestosterone did not. The diversity of patterns in androgen effects indicates that gonadal sex, aromatization of androgen, and perhaps gene dosage all influence the expression of steroid-receptor mRNAs in the lizard brain.

Androgens↗