Enhancement of 1,2-dimethylhydrazine-induced large bowel tumorigenesis in Balb/c mice by corn, soybean, and wheat brans

This study was designed to determine the effects of four well-characterized dietary brans on large bowel tumorigenesis induced in mice with 1,2-dimethylhydrazine (DMH). Eight-week-old barrier-derived male Balb/c mice were fed a semisynthetic diet with 20% bran added (either corn, soybean, soft winter wheat, or hard spring wheat) or a no-fiber-added control diet. Half of each group was given DMH (20 mg/kg body weight/week, subcutaneously for 10 weeks) beginning at 11 weeks of age. Surviving mice were killed 40 weeks after the first DMH injection. Tumors were not found in mice not subjected to DMH. In DMH-treated mice, tumors were found almost exclusively in the distal colon. Tumor incidences were as follows: controls, 11%; soybean group, 44%; soft winter wheat group, 48%; hard spring wheat group, 58%; and corn group, 72%. Tumors per tumor-bearing mouse ranged from 1.4 to 1.6, except in the corn group, which had 2.1. A positive correlation was found between percentage of neutral detergent fiber in the brans and tumor incidences but not between the individual components of cellulose, hemicellulose, or lignin. The enhancement of DMH-induced large bowel tumorigenesis by all four bran types may reflect a species and/or mouse strain effect that is bran-source related. These data emphasize the importance of using well-defined bran in all "fiber" studies.     

Morphine-induced metabolic changes in human brain. Studies with positron emission tomography and [fluorine 18]fluorodeoxyglucose

Morphine sulfate effects (30 mg, intramuscularly) on cerebral glucose utilization and subjective self-reports were examined in 12 polydrug abusers by positron emission tomography and [fluorine 18]fluorodeoxyglucose in a double-blind placebo-controlled crossover study. During testing, subjects sat with eyes covered, listening to white noise and "beep" prompts. Morphine significantly reduced glucose utilization by 10% in whole brain and by about 5% to 15% in telencephalic areas and the cerebellar cortex, assuming no contribution of hypercapnia. When the contribution of PaCO2 (45 minutes after morphine was administered) was partialled out, significant morphine-induced reductions persisted in whole brain and six cortical areas. Irrespective of morphine, left-greater-than-right asymmetry occurred in the temporal cortex, and an interaction between hemisphere and drug was noted in the postcentral gyrus. In most cases, effects on glucose utilization were not significantly related to measures of euphoria.     

In vivo labeling of sigma receptors in mouse brain with [3H]4-phenyl-1-(4-phenylbutyl)piperidine

4-Phenyl-1-(4-phenylbutyl)piperidine(4-PPBP) is a very potent ligand for σ (Sigma) receptors. The present study was undertaken to evaluate [³H]4-PPBPas a radioligand for in vivo labeling of cerebral σ receptors. After intravenous administration of [³H]4-PPBP to mice, there is high uptake of radioactivity in the brain. The regional distribution of radioactivity in the brain 2 h after intravenous injection of [³H]4-PPBP parallels the in vitro binding of the radioligand in rat brain (pons/medulla > cerebellum ≥ prefrontal cortex ≥ parietal cortex > hypothalamus > olfactory tubercle ≥ thalamus > hippocampus > striatum). Pretreatment with haloperidol (2 mg/kg) significantly decreases the radioactivity measured in the brain 30–120 min after injection of [³H]4-PPBP. Pretreatment with unlabeled 4-PPBP or ifenprodil also significantly decreases radioactivity in the brain 2 h after injection of [³H]4-PPBP, in a dosedependent manner. The in vivo binding of [³H]4-PPBP in the brain also is significantly inhibited by SL 82.0715, BMY 14802, 1,3-di-o-tolylguanidine (DTG), and (+)-enantiomers of pentazocine, SKF 10,047, and 3-PPP, but not by the corresponding (?)-enantiomers, consistent with stereoselectivity of inhibition obtained in in vitro binding studies. In contrast, pretreatment with dizocilpine and spiperone does not inhibit in vivo binding of [³H]4-PPBP. The results indicate that [³H]4-PPBP would be a suitable radioligand for in vivo labeling of σ receptors in brain. © 1995 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America

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Comparison of 7-nitroindazole with other nitric oxide synthase inhibitors as attenuators of opioid withdrawal

Previously, we demonstrated that two nonselective inhibitors of nitric oxide synthase (NOS),l-N ^G-nitroarginine (l-NNA) andl-N ^G-nitroarginine methyl ester (l-NAME), reduced some signs of morphine withdrawal in rats. The present work extended these studies to include 7-nitroindazole (7-NI), an inhibitor specific for cerebral NOS, andN(5)-(1-iminoethyl)-l-ornithine (l-NIO), a potent inhibitor of endothelial NOS. Behavioral effects of these four NOS inhibitors and clonidine, an ₂-adrenoceptor, agonist, on morphine withdrawal in rats were assessed. Rats received one 75-mg morphine pellet subcutaneously (SC). Three days later, NOS inhibitors were administered IP 1 h before withdrawal was precipitated with naloxone (0.5 mg/kg, SC) and scored. 7-NI,l-NIO,l-NAME andl-NNA produced dose-related decreases in weight loss, diarrhea, wet dog shakes and grooming. 7-NI also reduced mastication, salivation and genital effects. Clonidine produced effects similar to 7-NI. In awake, morphine-naive and morphine-dependent rats not subjected to withdrawal, 7-NI was the only NOS inhibitor that did not increase blood pressure. Because 7-NI attenuated more signs of opioid withdrawal thanl-NNA,l-NAME orl-NIO without causing hypertension, 7-NI appears to warrant further testing as a potential candidate for human use.Abstracts were presented at the annual meetings of the College on Problems of Drug Dependence, West Palm Beach, Fla., 18–23, June 1994; International Narcotics Research Conference, North Falmouth, Cape Cod, Mass., 16–21, July 1994; and a Satellite Symposium to IUPHAR, Montreal, Canada, 22–24, July 1994.     

Education and audit can improve the identification of excessive drinkers among medical inpatients

This study investigated the effect of education and audit on the identification and management of medical inpatients with excessive alcohol consumptions by use of a cross-sectional survey of medical and nursing notes, compared with historical controls. We report the proportion of medical and nursing notes containing qualitative and quantitative drinking histories, the use of the CAGE questionnaire, and notification of alcohol consumption in discharge summaries. A total of 1,979 out of 2,680 (74%) notes of eligible patients were examined. The number of medical notes containing quantitative alcohol histories rose from 175/792 (22%) among historical controls, to 242/690 (35%) after training of junior medical and nursing staff, and to 241/497 (48%) after feedback of results in a clinical audit meeting. The number of medical notes with no recorded alcohol history changed from 309/792 (39%) to 287/690 (42%) to 152/497 (31%), respectively (chi 2 for trend = 97.2, p < 0.0001). The number of nursing notes containing quantified alcohol histories rose from 31/792 (4%) among historical controls, to 123/690 (18%) after training, and to 237/497 (48%) after feedback of results in a clinical audit meeting. The number of nursing notes with no recorded alcohol history fell from 309/792 (90%), to 512/690 (74%), to 205/497 (41%) respectively (chi 2 for trend = 353.7, p < 0.0001). The proportion of patients found to be drinking excessively rose from 40/792 (5.1%) to 57/690 (8.3%) to 45/497 (9.1%) (chi 2 for trend = 8.25, p = 0.004). There was little worthwhile improvement in use of the CAGE questionnaire and in discharge summaries. Education and audit are effective ways of improving the identification of excessive drinkers by both junior doctors and nurses alike. Other aspects of management are less responsive.     

Silo gas exposure in New York state following the dry growing season of 1995

Exposure to silo gas is a recognized agricultural hazard. Silo gas produced from corn fermentation may consist of oxides of nitrogen and carbon dioxide. The presence of potentially lethal concentrations of nitrogen dioxide (NO2) within vertical silos has been well documented. The risk of silo gas exposure from other silage storage methodologies--including horizontal "ag-bags" and concrete bunkers--has been less well characterized. A dry growing season is known to be a factor for elevating nitrate levels in corn plants and can result in increased NO2 production. Farms in the northeastern United States faced drought conditions during the 1995 growing season. The New York State (NYS) Department of Health (DOH) and the New York Center for Agricultural Medicine and Health (NYCAMH) investigated four exposure incidents involving six farmworkers during September/October 1995. Four of these workers were hospitalized for multiple days, with two workers receiving treatment in intensive care units. The remaining two workers were treated in hospital emergency departments; one refused admission and left against medical advice. We monitored NO2 levels from "ag-bags" at several New York farms. For four days, outdoor concentrations of NO2 at one site remained in excess of the National Institute for Occupational Safety and Health's (NIOSH) immediately dangerous to life and health value (IDLH) of 20 ppm. As a result of the clinical and industrial hygiene data, and the growing season's abnormal weather conditions, DOH and NYCAMH issued statewide health hazard alerts and conducted educational activities to warn farmers and their families. The findings of this study reinforce the potential hazards associated with silo gas exposure and identify the use of ag-bags as a relatively new avenue for significant worker exposure.     

Enhancing the identification of excessive drinkers on medical wards: a 1-year follow-up study

This paper describes a 1-year follow-up study examining whether hospital ward doctors and nurses continue to take quantitative alcohol histories and provide brief intervention to problem drinkers on general medical wards after the introduction of a simple protocol. Regular training in the use of this protocol was stipulated in the annual service contract between the Health Authority and the Hospital Trusts. Improvements in staff practice persisted at 1-year follow-up, although it fell from a peak at an earlier phase of the study. The positive role of state purchasers of health services in sustaining improvements in clinical practice is discussed.