Species differences in the hydrolysis of 2-cyanoethylene oxide, the epoxide metabolite of acrylonitrile

The carcinogenic effects of acrylonitrile in rats are believedto be mediated by its DNA-reactive epoxide metabolite, 2-cyanoethyleneoxide (CEO). Previous studies have shown that conjugation withglutathione is the major detoxication pathway for both acrylonitrileand CEO. This study investigated the role of epoxide hydrolasein the hydrolysis of CEO by HPLC analysis of the products from[2,3-¹⁴C]CEO. CEO is a relatively stable epoxide with a half-lifeof 99 min at 37°C in sodium phosphate buffer (0.1 M), pH7.3. Incubation with hepatic microsomes or cytosols from maleF-344 rats or B6C3F1 mice did not enhance the rate of hydrolysisof CEO (0.69 nmol/min). Human hepatic microsomes significantlyincreased the rate of hydrolysis of CEO, whereas human hepaticcytosols did not. Human hepatic microsomal hydrolysis activitywas heat-sensitive and potently inhibited by 1,1,1-trichloropropeneoxide (IC₅₀ of 23 µM), indicating that epoxide hydrolasewas the catalyst. The hydrolysis of CEO catalyzed by hepaticmicrosomes from six individuals exhibited normal saturationkinetics with K_M ranging from 0.6 to 3.2 mM and V _max from 8.3to 18.8 nmol hydrolysis products/min/mg protein. Pretreatmentof rodents with phenobarbital or acetone induced hepatic microsomalhydrolysis activity toward CEO, whereas treatment with ß-naphthoflavone,dexamethasone or acrylonitrile itself was without effect. Thesedata show that humans possess an additional detoxication pathwayfor CEO that is not active in rodents (but is inducible). Thepresence of an active epoxide hydrolase hydrolysis activitytoward CEO in humans should be considered in assessments ofcancer risk from acrylonitrile exposure.     

A study of 10 cases of velopharyngeal incompetence treated by flap pharyngoplasty

Velopharyngeal incompetence (VPI) is a condition of incomplete closure of V.P. port area, normally formed by velum and posterior pharyngeal watt. The condition primarily results in various types of speech defects, which form- the main complaint of the patient. We have studied 10 cases of VPI due to various causes and the speech improvement obtained by flap pharyngoplasty procedures. The results have been evaluated with a follow-up of six months. Highly encouraging results only indicate a more frequent need to undertake such surgery without any hesitation if the ENT surgeon is familiar with and has an adequate exposure to this simple and effective procedure.     

Detection of Human T-Lymphotropic Virus (HTLV) tax Sequences in New York City Blood Donors Seronegative for HTLV Types 1 and 2

A potential public health concern is the reported detection of the human T-lymphotropic virus (HTLV) tax gene in the lymphocytes of up to 11% of a low-risk group of New York City blood donors (NYBD). This study aimed to independently confirm the prevalence of HTLV tax sequences in 293 NYBD. All NYBD tested negative for antibodies to HTLV types 1 and 2 and HTLV Tax. HTLV tax sequences were not detected in the NYBD lymphocytes. These data demonstrate the lack of HTLV-1 tax in this group of NYBD at low risk for HTLV infection.     

印度结核病流行病学:综述

印度的结核病形势可以用高患病率、高发病率高传染率来描述。自二十世纪50年代以来在印度不同地区进行的疾病监测报告显示:涂阳肺结核患病率为0.6-7.6/1000,培阳肺结核患病率为1.7-9.8/1000,培阳和/或涂阳结核患病率为1.8-12.7/1000。从已进行的有限的研究资料分析,涂阳肺结核的发病率在1.0-1.6/1000之间,培阳肺结核发病率在1.0-2.5/1000之间。根据不同时期在不同地区进行的结核菌素监测估计,结核年感染率(ARTI)为1-2%。在2000-2003年进行的全国范围研究估计,平均ARTI为1.5%。多数在第3级卫生保健中心进行的研究显示在结核病例中人类免疫缺陷病毒(HIV)血清阳性率在增加,不同研究的结果介于0.4%-28.8%之间。新病例中耐多药(MDR)率相对较低,约0.5-5.3%之间。但在复治病例中MDR为8%-67%。     

Primer sensitivity: can it influence the results in Enterococcus faecalis prevalence studies?

BACKGROUND/OBJECTIVE: Recent polymerase chain reaction (PCR)-based studies have shown significant variability in the prevalence of Enterococcus faecalis cases with nonhealing endodontic infections. This variability may be, at least in part, due to the differences in sensitivities of the primers used. The purpose of this study was to compare the sensitivity of 3 sets of PCR primers which have been reported in the endodontic literature. METHODS: The 3 primers sets used were: group 1) tuf gene-based primers with genus-level specificity; and groups 2 and 3) 16S rDNA-based primers that were E. faecalis specific. Three strains of E. faecalis at concentrations of 10(2)-10(8) cells/mL were included in this study. RESULTS: The PCR amplification of E. faecalis strains with the 3 primer pairs showed that group 1 primers consistently had the highest sensitivity, followed by group 2 and group 3 (P<.0001). CONCLUSION: A tuf-based PCR identification assay followed by direct sequencing would yield accurate and consistent prevalence rates of E. faecalis in endodontic infections.     

Oral clonidine pretreatment for haemodynamic stability during craniotomy.

We have studied the effect of clonidine pretreatment on cardiovascular responses to various stimuli during craniotomy. Fifty-eight patients (ASA Class I-II), scheduled for supratentorial surgery, were randomly given either oral clonidine, mean dose 3.6 micrograms/kg (n = 28), or oral diazepam, 0.2 mg/kg (n = 30), ninety to one hundred minutes before surgery. Anaesthesia was induced with thiopentone and maintained with nitrous oxide:oxygen, pentazocine and halothane. Pancuronium was used as a neuromuscular blocker. Mean arterial pressure and heart rate were recorded before and after several stimuli. In the clonidine group hypertensive response was significantly less on laryngoscopy (6.5% increases versus 11.2% in the diazepam group), intubation (9.2% versus 16.5%), Mayfield clamp application (14.5% versus 29.91%) and after skin infiltration with lignocaine-adrenaline solution (2.95% versus 5.42%). Heart rate response to laryngoscopy, intubation and skin infiltration was also significantly attenuated in the clonidine group. The sleep dose of thiopentone was smaller in patients pretreated with clonidine. Patients in the diazepam group required more medical intervention. No adverse effect occurred in any patient.     

Microbiological study of vaginal discharge associated with the use of CuT 200.

A microbiological study of the vaginal discharge was conducted on 75 women attending family planning outdoors. In 24 out of 25 symptomatic CuT 200 users suffering from non-specific vaginitis, Gardnerella vaginalis was isolated from 19 cases (79%). The difference in the recovery rate of Gardnerella vaginalis was highly significant between symptomatic CuT 200 users and non-users (p less than 0.001) and that between symptomatic and asymptomatic CuT 200 users (p less than 0.05). But the difference between asymptomatic CuT 200 users and non-users was not statistically significant. The presence of clue cells on direct Gram's staining of vaginal discharge is significantly (p less than 0.05) related to the recovery of Gardnerella vaginalis on culture.