Biomedical subjects

G Hebert

Publications and source records attributed to G Hebert.

11 recordsLinked to original sources

PubMed1997

Ankle radiograph utilization after learning a decision rule: a 12-month follow-up.

OBJECTIVE: To test whether the reduction in ankle radiograph ordering was sustained during a 12-month period after a formal trial to introduce the Ottawa ankle rules. METHODS: A before-after clinical trial of ankle radiograph ordering practice was performed in a university-based ED. All 1,884 (947 "during intervention," 937 "postintervention") adults seen with acute ankle injuries during 2 12-month trial periods were evaluated. The behavioral intervention was the teaching of the Ottawa ankle rules and feedback of compliance with the rules during the intervention period. No further education about the ankle rules or feedback regarding compliance occurred during the postintervention year. Physicians were unaware of any postintervention surveillance. The primary outcome was the proportion of eligible patients referred for an ankle radiograph during the intervention and postintervention periods. RESULTS: During the intervention period (January 1-December 31, 1993), the proportion of patients who received an ankle radiograph [609 x-rayed of 947 patients seen (64.3%; 95% CI 61.2-67.4%)] did not differ from the proportion who received an x-ray in the postintervention period (January 1-December 31, 1994) [583 x-rayed of 937 patients seen (62.2%; 95% CI 59.1-65.3%), p = 0.65, power > 0.80 to detect a 10% increase in the radiograph ordering rate]. There was also no difference in the radiograph ordering rate in the first 3 months of the postintervention period compared with the last 3 months of the postintervention period (68.8% vs 64.7%, respectively, p > 0.30). CONCLUSIONS: Compliance with the Ottawa ankle rules was sustained during a 12-month postintervention surveillance period when physicians did not know they were being observed. Physicians will continue to use a simple clinical guideline once it has been learned.

Adolescent↗

PubMed1990

Further studies of the effects of intranigral morphine on behavioral responses to noxious stimuli.

Bilateral intranigral microinjection of morphine produces dose-related and naloxone reversible analgesic-like effects on the hot-plate and tail-flick tests. The main objectives of the present studies were to further characterize the analgesic-like effects of intranigral morphine, to determine whether these effects were related to a general impairment of sensory or motor function, and to assess their anatomical specificity. The principal findings are: (1) intranigral morphine (10 micrograms) suppresses pain-related behavior without altering responses to a variety of non-noxious auditory, visual, and somatic stimuli, and without producing motor impairment; (2) movement of injector needles approximately 1 mm rostral, dorsal, or medial to the active nigral site significantly reduces the analgesic-like effect of morphine on the tail-flick test; and (3) electrolytic lesions confined to the nigra significantly reduced the analgesic-like effect of morphine on the hot-plate test. It is concluded that the analgesic-like effects of intranigral morphine are mediated by the substantia nigra and that these effects are specifically related to pain.

Animals↗

PubMed1990

In vivo biological response to recombinant interferon-gamma during a phase I dose-response trial in patients with metastatic melanoma.

Interferon-gamma (IFN gamma), as produced by recombinant DNA technology, has shown a wide range of immunomodulatory activity in vitro and in vivo. Clinical studies have attempted to establish a dose-response relationship to define optimal dosage ranges for induction of effector cell function and host response in patients with cancer. We conducted a randomized trial to test the in vivo biologic activity of five daily dosages ranging from 3 to 3,000 micrograms/m2, administered by daily 2-hour bolus injection or by continuous infusion for 14 days. We demonstrate comparable immunobiologic effects of recombinant IFN gamma (rIFN gamma; Biogen, Inc, Cambridge, MA) administered by these two schedules at the various dosages tested, and have defined a relationship of dose to biologic response over this 3-log10 dose range. Oligo 2'5' adenylate synthetase (2'5'As) induction, natural-killer (NK) cell activity, and T-cell subset distribution (heightened T helper/suppressor ratio) showed the most consistent treatment-associated changes and the greatest immunobiologic effects at dosages of 300 to 1,000 micrograms/m2. Mononuclear cell DR and DQ antigen expression showed no consistent dose-related treatment effect. The relevance of the phenotypic, functional, and enzymologic effects observed in this trial to any clinical antitumor effects of IFN gamma in cancer therapy must now be established.

2',5'-Oligoadenylate Synthetase↗

PubMed1989

Pentobarbital attenuates the antinociceptive effect of intranigral morphine.

This study was conducted to characterize the temporal relationship between intranigral injection of morphine and the onset of antinociception. The principal findings are: 1) morphine produces antinociception on the hot plate test within three minutes after intranigral injection, 2) the tail flick reflex cannot be measured within the first 30 minutes following intranigral morphine due to motor effects, and 3) pentobarbital suppresses the antinociceptive effect of intranigral morphine on the tail flick test. These findings support the conclusion that the antinociceptive effects of intranigral morphine are mediate by the substantia nigra.

Animals↗

PubMed1989

Evidence that physical dependence on morphine is mediated by the ventral midbrain.

Rats were given daily injections of increasing doses of morphine sulfate (40-100 mg/kg, s.c.), for 4 days. Twenty hours after the last injection of morphine, the animals received bilateral injections of naloxone (1-10 micrograms) into the substantia nigra, ventral tegmental area or sites 2 mm rostral, caudal or dorsal to the site in the nigra. Withdrawal signs were monitored for 20 min after the intracerebral injection. Naloxone administered into the nigra in morphine-dependent rats produced dose-dependent significant increases in wet dog shakes, irritability to touch, teeth chattering, diarrhea and locomotion, compared to morphine-dependent animals that received injections of saline into the nigra. The injection of naloxone (3 micrograms) into the ventral tegmental area of morphine-dependent animals, produced irritability to touch and diarrhea, compared to morphine-dependent controls that received saline in this region of the brain. Significant differences in withdrawal signs were observed between morphine-dependent animals, that received injections of naloxone (3 micrograms) into the nigra and those that received naloxone (3 micrograms) into the ventral tegmental area or rostral or caudal sites. No differences between the substantia nigra and the dorsal sites were observed. However, withdrawal symptoms were produced by injections of naloxone into the substantia nigra and ventral tegmental area, even when the guide cannulae were angled to avoid penetration of sites dorsal to these regions of the brain. Naloxone, injected into the ventral midbrain of non-dependent animals, produced no signs of withdrawal. These studies suggest that the ventral midbrain mediates physical dependence on morphine.

Animals↗

PubMed1978

Radiographic characteristics of male breast cancer.

The authors studied 171 male breast tumors (20 cancers and 151 benign lesions) from 1969 to 1977. A proposed symptomatic triad can lead to an early radiological diagnosis of male breast cancer, even without evidence of advanced disease: small mass, well defined contours, and eccentric location in relation to the nipple.

Breast Diseases↗

PubMed1978