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Biomedical subjects

N C Gordon

Publications and source records attributed to N C Gordon.

At least 19 recordsLinked to original sources
PubMed1996

Gender difference in analgesic response to the kappa-opioid pentazocine.

Gender difference in analgesia produced by the kappa-opiate pentazocine was investigated in a model of post-operative dental pain. In a recent study [Gordon et al., Neuroscience, 69 (1995) 345-349.] evaluating interaction between the GABAB agonist baclofen and opiates with respect to postoperative analgesia we found that females receiving pentazocine for the treatment of postoperative pain showed better analgesia than did males receiving similar treatment. To follow-up this result, we evaluated for the effect of gender on analgesia produced by pentazocine administered to participants not receiving another experimental medication. The analgesic response to pentazocine in ten females was compared to that in eight males. All participants were administered pentazocine after undergoing surgery for the removal of impacted third molars. We confirm our previous finding that pentazocine produces significantly greater analgesia in females than in males; no significant difference was observed in analgesia among females in different phases of the menstrual cycle.

Adult↗
PubMed1995

Enhancement of morphine analgesia by the alpha 2-adrenergic antagonist yohimbine.

Although interactions between opioids and adrenergic agonists in the treatment of pain have been demonstrated in humans, the contribution of specific adrenergic receptors in this interaction remains to be clarified. In a double-blind, placebo-controlled study in male patients with postoperative dental pain, we investigated the effect of preoperative administration of the alpha 2-adrenergic antagonist, yohimbine, on analgesia produced by postoperative intravenous morphine. Although yohimbine by itself did not affect the pain, the overall analgesic effect of morphine was significantly enhanced in the presence of yohimbine. This report is the first to demonstrate that an alpha 2-adrenergic antagonist enhances opiate analgesia in humans.

Adrenergic alpha-2 Receptor Antagonists↗
PubMed1995

Enhancement of morphine analgesia by the GABAB agonist baclofen.

Opioid-GABAergic interactions for the treatment of post-operative pain were investigated in two double-blind, placebo-controlled experiments. We first studied the effect of pre-operatively administered baclofen, a GABAB receptor agonist, on the analgesia produced by intravenously administered morphine, a predominantly mu-opioid analgesic. In a separate trial, we studied the effect of baclofen on the analgesia produced by pentazocine, a predominantly kappa-opioid analgesic. While baclofen alone did not affect the level of post-operative pain, morphine analgesia was significantly enhanced by baclofen compared to placebo. In contrast, baclofen did not affect the level of pentazocine analgesia: however, females receiving pentazocine showed significantly greater analgesia than males.

Adult↗
PubMed1990

Fixation of mandibular fractures: a comparative analysis of rigid internal fixation and standard fixation techniques.

This study used a prospective design to compare standard therapy (closed or open reduction with 4 weeks of maxillomandibular fixation) to rigid internal fixation (RIF) for the treatment of mandibular fractures. Ninety-two patients with 143 fractures were evaluated and treated. There was no statistically significant difference in the treatment results between the two groups, despite a bias in the distribution of study variables that favored the standard therapy.

Adult↗
PubMed1988

Potentiation of pentazocine analgesia by low-dose naloxone.

The analgesia produced by combinations of low-dose naloxone with pentazocine or morphine was studied in 105 patients with moderately severe postoperative pain after standardized surgery for removal of impacted third molars. Pain intensity was quantified using a visual-analogue scale. To eliminate the release of endogenous opioids produced by the placebo component of open drug administration, all injections were made by a preprogrammed infusion pump. The analgesia produced by pentazocine, an agonist-antagonist opiate-analgesic acting predominantly at the kappa opiate receptor, was potentiated by low-dose naloxone, whereas the analgesia produced by morphine, a mu-agonist, was attenuated by low-dose naloxone. To evaluate whether similar potentiation would be present in an animal model, and specifically, in the absence of diazepam, which patients receive, we performed an analogous experiment in rats in which nociceptive threshold was determined using the Randall-Selitto paw-withdrawal test. The results were completely analogous to the clinical results: pentazocine analgesia was potentiated by low-dose naloxone, whereas morphine analgesia was attenuated by low-dose naloxone. These data demonstrate a novel interaction between opiates, and suggest a rationale for opiate combinations to produce potent analgesia with fewer autonomic side effects and less abuse potential than presently available analgesics.

Analgesia↗
PubMed1986

Method of administration determines the effect of naloxone on pain.

The opiate antagonist, naloxone, produces dose-dependent biphasic changes in clinical pain. The mechanism of the analgesia produced by low dose naloxone is unknown. To study the analgesic effect of naloxone, we have used a programmable infusion pump, which eliminates placebo-induced endorphin-mediated analgesia, to administer different doses of naloxone. We report that use of machine infusion of naloxone exclusively produces analgesia. The implications of this finding to the mechanism of naloxone-induced analgesia are discussed.

Analgesics↗
PubMed1984

The role of stimulus intensity and stress in opioid-mediated analgesia.

Rats exposed to a Pavlovian conditioning paradigm developed naloxone-reversible analgesia only when the intensity of a noxious unconditioned stimulus was suprathreshold and the level of stress was augmented. The time course of the onset of this conditioned analgesia was reproduced by systemic administration of morphine. These findings suggest that both a minimal level of stimulus intensity and stress are necessary for the activation of endogenous opioid-mediated analgesia.

Analgesia↗
PubMed1984

Pain-induced vocalization in the rat and its modification by pharmacological agents.

Vocalization was induced in rats by electrical stimulation of the tail (pain-induced vocalization), and its components were characterized in terms of latency, duration, frequency spectrum and energy. Noxious stimuli at threshold elicit a single vocalization component (V1). Increases in stimulus intensity produce additional discrete vocalization components (V2-Vn) with successively longer latencies, termed the vocalization afterdischarge (AD). The AD components are acoustically similar to each other but differ significantly from the V1 component. The duration, the specific acoustic measures and the sound energy of both V1 and AD components are positively correlated with intensity of the stimulus. The dependence of the V1 and AD components on the affective state of the rat was evaluated by comparing the acoustic characteristics of both components to those of stress-induced vocalizations, and by studying the effects of the anxiolytic drug diazepam and physical restraint on the threshold of V1 and AD. The AD components were markedly more dependent on the affective state of the rat then was the V1 component. A moderately low dose of morphine (3.0 mg/kg) also preferentially affected the AD component, suggesting that a significant portion of the action of morphine on pain-induced vocalization is mediated through its action on the affective state of the rat.

Animals↗
PubMed1983

Relationship of duration of analgesia to opioid pharmacokinetic variables.

That physiological effects are directly related to concentration at the site of action has been validated for only a few classes of drugs. For opiates, a direct correlation is known to exist between concentration and magnitude of analgesia, but has not been shown for duration of analgesia. These experiments in rats, using opiates whose elimination half-lives differ by a factor of 2 1/2, in a range of doses that produce 10-90% of maximal analgesic effect, show that duration is not dependent on dose or rate of elimination of opiate analgesics. The data suggest that analgesic duration is not determined by the pharmacokinetics of opiates at the receptors where these drugs act to elicit analgesia.

Animals↗
PubMed1982

Post-operative pain: effect of extent of injury and attention.

The relationship to pain level of extent of injury (as measured by number of teeth extracted) and attention paid to the injury (as measured by frequency of pain ratings) was studied in patients with dental postoperative pain. Patients had either 2 or 4 impacted wisdom teeth removed and rated their pain either 2 or 5 times during the experiment. A positive correlation was found between extent of injury and reported pain level as well as between frequency of pain rating and pain level. The correlation between frequency of pain rating and pain level was found only in patients with 4 teeth extracted. To our knowledge, this is the first study which quantitatively evaluates the relationship between amount of injury and level of pain. This study also suggests that the degree to which manipulations of psychological variables alter an individual's pain perception may depend on the extent of injury.

Adolescent↗
PubMed1981

Self-instruction guides in the undergraduate oral surgery curriculum.

A study was undertaken to evaluate the self-instruction guides in oral surgery developed at the University of Washington School of Dentistry. The third-year dental class enrolled in the basic oral surgery course was divided into four groups. Group I received the traditional lecture series and textbook. Group II attended the lectures series, used the standard textbook, and were given the guides to study at their own convenience. Students in Group III received only the self-instruction guides and were assigned to review them in a study hall during the usual lecture hours. Members of Group IV were given only the guides to be studied at their own convenience. Scores on the midterm and final examinations and on the oral surgery section of the National Dental Board examination showed no significant differences in performance among the four groups, indicating that students can learn oral surgery from these self-instruction guides.

Curriculum↗
PubMed1980

Medical palatine cyst and maxillary antral osteoma: report of an unusal case.

A case is presented of a patient with the coincidental occurrence of two unusual lesions, median palatine cyst and osteoma of the maxillary antrum. There was no atypia of either lesion, but this combination led to the impression that the median palatine cyst had eroded into the maxillary antrum. Both lesions are usually asymptomatic and were incidental findings in this case. An occlusal radiograph is best for showing the palatal radiolucent area and is usually diagnostic. The preferred treatment for median palatine cyst is enucleation; a palatal splint is an excellent aid for reapproximation of the mucoperiosteal flap. The maxillary antrum was explored to obtain a biopsy specimen for a microscopic diagnosis of the radiopaque lesion; this proved to be an osteoma. The diagnosis of an osteoma is an indication for a radiographic survey to rule out Gardner syndrome, which has serious implications.

Humans↗
PubMed1980

Closure of oronasoantral defects: report of case.

A brief review of the techniques for closure of defects of the palate is presented. A case is reported in which an oronasoantral defect was successfully closed using the Fickling's inkwell technique. The importance of delayed closure and careful planning and preparation of the flap is emphasized.

Female↗