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Biomedical subjects

J Stewart

Publications and source records attributed to J Stewart.

At least 307 records · Page 17Linked to original sources
PubMed1993

Postoperative pain management and acute pain service activity in Canada.

A survey of postoperative pain management practices was mailed to the 56 Canadian university-affiliated teaching hospitals in December 1991. The aims of the survey were (1) to determine the prevalence, structure, and function of Acute Pain Services and (2) to determine the use and management of patient-controlled analgesia (PCA) and epidural opiate analgesia (EOA) in teaching hospitals. Responses were received from 47 hospitals, representing a return rate of 84%. Twenty-five hospitals (53%) operated an Acute Pain Service and an additional 17 (35%) were attempting to organize one. "Time commitment" was given as the primary reason why hospitals were unable to offer an Acute Pain Service. Most commonly used methods of pain relief were EOA and PCA. Most services were multidisciplinary, with 60% having a nurse and 29% a pharmacist. Irrespective of the presence of an Acute Pain Service, PCA was used at 32 (68%) hospitals, and EOA was used at 41 (87%); however, only 15 provided EOA on general wards. Complications have occurred with both PCA and EOA, with 14 of 32 hospitals indicating that they have had a major or serious complication. The data suggest an estimated incidence of severe respiratory depression of 0.03% with PCA and 0.13% with EOA. No deaths were reported at the time of the survey. Epidural opioid-local anaesthetic EOA-LA combinations were used at 26 (63%) hospitals; however, only six administered these combinations on general words. We conclude that a multidisciplinary team approach to manage postoperative pain is viable in university teaching hospitals of all sizes.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1993

Enhancement of the prophagic but not of the antidipsogenic effect of U-50, 488H after chronic amphetamine.

Two groups of rats were treated with seven daily injections of either saline or d-amphetamine (3 mg/kg IP). On the 2 days following the last injection, rats were tested according to a counterbalanced experimental design, each animal receiving, immediately prior to the beginning of the dark phase, saline on one day and the highly selective kappa-opioid agonist trans- +/- 3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]-benzene- acetamide methanesulfonate hydrate [U-50,488H (U50)] on the other. A microcomputer-controlled data acquisition system was used for the structural analysis of the feeding and drinking responses to amphetamine and U50. U50 enhanced feeding and depressed drinking in the first hour. The increased food intake was probably the result of the effect of U50 on the development of satiation and duration of satiety. Chronic amphetamine potentiated the prophagic effect but not the antidipsogenic effect of U50. The structural analysis demonstrated that the characteristics of the prophagic effect of U50 were amplified but not changed.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1993

Naloxone potentiation of novelty-induced hypoalgesia: characterization of the alpha-noradrenergic receptor subtype.

Repeated daily administration of the opiate receptor antagonist naloxone (10 mg/kg) attenuates the habituation of novelty-induced hypoalgesia. This effect can be reversed by the alpha 2-noradrenergic receptor agonist clonidine and enhanced by the alpha 2-antagonist yohimbine. The present experiments were conducted to provide further support for the importance of the alpha 2-receptor and determine the possible influence of the alpha 1-receptor. Naloxone's effect on novelty-induced hypoalgesia was not affected by pretreatment with the specific alpha 1-receptor antagonist prazosin (0.2-1.0 mg/kg, SC) or the nonselective alpha antagonist phentolamine (2.0-10.0 mg/kg). In a second series of experiments, it was found that the potentiation of naloxone's effect by yohimbine (2 mg/kg) was reversed by clonidine (0.1 mg/kg) but was not influenced by prazosin or phentolamine. These results suggest that the alpha 1-noradrenergic receptor subtype does not mediate the effect of naloxone on novelty-induced hypoalgesia. They also reinforce the importance of the alpha 2-receptor subtype in the mediation of this effect.

Animals↗
PubMed1993

Sex differences in amphetamine-induced locomotor activity in adult rats: role of testosterone exposure in the neonatal period.

The present studies assessed the extent to which adult sex differences in responsiveness to both acute and repeated amphetamine (AMPH) treatment can be attributed to differential exposure to testosterone (T) during the early critical period for sexual differentiation. At birth, male pups were sham-operated or gonadectomized, whereas female pups were given T or an oil injection. In adulthood, all animals were gonadectomized or sham-operated. Locomotor activity in response to either 1.5 mg/kg AMPH (IP) or the saline vehicle was measured for 2 h every third day, on five occasions. On the sixth occasion, all animals received 0.75 mg/kg AMPH (IP) in a test for sensitization. In Experiment 1, animals were tested in the absence of circulating gonadal hormones, whereas in Experiment 2, all animals received 5.0 micrograms estradiol benzoate (SC), 30-35 min prior to each behavioral test. Results indicate that neonatal exposure to T suppresses responsiveness to AMPH in adulthood. The differences between neonatal T-exposure groups were magnified in the presence of circulating estradiol. The fact that female animals were more responsive to AMPH regardless of neonatal T exposure suggests that lifetime exposure to estradiol alters responsiveness to this hormone, and to AMPH, in adult animals and/or that exposure to T both pre- and postnatally is necessary for the full suppression of responsiveness seen in adult male animals.

Amphetamine↗
PubMed1993

Factors enhancing adherence of toxigenic Staphylococcus aureus to epithelial cells and their possible role in sudden infant death syndrome.

Toxigenic strains of Staphylococcus aureus have been suggested to play a role in sudden infant death syndrome (SIDS). In this study we examined two factors that might enhance binding of toxigenic staphylococci to epithelial cells of infants in the age range in which cot deaths are prevalent: expression of the Lewis(a) antigen and infection with respiratory syncytial virus (RSV). By flow cytometry we demonstrated that binding of three toxigenic strains of S. aureus to cells from nonsecretors was significantly greater than to cells of secretors. Pre-treatment of epithelial cells with monoclonal anti-Lewis(a) or anti-type-1 precursor significantly reduced bacterial binding (P < 0.01); however, attachment of the bacteria correlated only with the amount of Lewis(a) antigen detected on the cells (P < 0.01). HEp-2 cells infected with RSV bound significantly more bacteria than uninfected cells. These findings are discussed in context of factors previously associated with SIDS (mother's smoking, bottle feeding and the prone sleeping position) and a hypothesis proposed to explain some cases of SIDS.

Antibodies, Monoclonal↗
PubMed1993

Effect of respiratory syncytial virus infection on binding of Neisseria meningitidis and Haemophilus influenzae type b to a human epithelial cell line (HEp-2).

It has been suggested that individuals might be more readily colonized with bacteria that cause meningitis through enhanced binding of the bacteria to virus-infected epithelial cells. As respiratory syncytial virus (RSV) affects infants and children in the age group also susceptible to bacterial meningitis, we tested the hypothesis that infection of HEp-2 cells by RSV might enhance binding of Neisseria meningitidis or Haemophilus influenzae type b (Hib). Attachment of fluorescein-labelled bacteria to HEp-2 cells was measured by flow cytometry, and RSV-infected cells bound significantly more meningococci (P < 0.001) and Hib (P < 0.01) than uninfected cells. Although the isolates expressed different antigenic characteristics (3 meningococci and 5 Hib), all showed a similar pattern of binding. The results are discussed with reference to the methods used for detection of bacterial binding and to interactions that might explain the increased binding to RSV-infected cells.

Bacterial Adhesion↗
PubMed1993

Effects of acute and chronic alprazolam treatment on cerebral blood flow, memory, sedation, and plasma catecholamines.

The effects of 0.014 mg/kg intravenous alprazolam administration on cerebral blood flow (CBF), memory, sedation, and plasma norepinephrine and epinephrine were determined in eight healthy males at baseline levels and following 1 week of daily oral alprazolam treatment. At baseline, intravenous alprazolam administration caused acute reductions in whole-brain CBF (25% to 30% decrease), memory, plasma epinephrine, and self-rated alertness. Following 1 week of alprazolam treatment, tolerance developed to the acute effects of intravenous alprazolam on CBF, memory, and plasma epinephrine. There were no consistent regional neuroanatomic differences in the CBF effects of acute alprazolam, or in the development of tolerance to these effects, and no correlations between the various measures of acute alprazolam effects on either test day.

Administration, Oral↗
PubMed1993

Vertical fixation disparity in learning disabled.

In this correlation study of visual parameters as related to learning disabilities, we considered several deficits: uncorrected refractive error, accommodative infacility, inaccurate pursuits, and vertical fixation disparity. Because vision is the primary sensory input involved in reading, it is nothing new to find a correlation between visual deficits and learning problems; however, vertical fixation disparity, unique in its relation to other sensory systems, deserves a great deal of attention. The high incidence of vertical fixation disparity measured in 5th and 6th graders with learning disabilities suggests that there is a plausible causal relation. Vertical oculomotor imbalance, vestibular problems, and learning disability are discussed.

Accommodation, Ocular↗
PubMed1993

The effect of parents' alcohol problems on children's behaviour as reported by parents and by teachers.

Associations between parents' alcohol problems when children were aged 9 and children's behaviour at ages 9 and 13 as reported by parents and teachers were investigated. The sample consisted of participants in a multidisciplinary longitudinal study, data were collected by face-to-face interview. When compared to children with no or mild parental alcohol problems, children classified as having severe parental alcohol problems were more likely to display high levels of problem behaviour at age 9 as reported by teachers and at age 13 as reported by parents. Poorer family relationships, lower verbal and reading proficiency and being male were also associated with high levels of behaviour problems.

Achievement↗
PubMed1993

Management of obstructing lesions of the left colon by resection, on-table lavage, and primary anastomosis.

BACKGROUND: The purpose of this study was to assess the feasibility and safety of single-stage resection, on-table lavage, and primary anastomosis in patients presenting with obstruction of the left colon. METHODS: The outcome of surgery in 73 consecutive patients presenting with obstruction of the left colon during a 5-year period was assessed in terms of perioperative complications and long-term survival. RESULTS: Sixty-three patients (86%) underwent single-stage restorative procedures. In this group there were four clinical anastomotic leaks (6%). However, there were no deaths as a result of leakage. There were four deaths (6%) but these were not due to anastomotic leakage. Long-term survival rates compared favorably, stage for stage, with large published series of elective experience. CONCLUSIONS: We believe that resection, on-table lavage, and primary anastomosis constitute the operation of choice for most patients with acute obstruction of the left colon.

Anastomosis, Surgical↗
PubMed1992

The stimulation of central kappa opioid receptors decreases male sexual behavior and locomotor activity.

Systemic injections of the kappa (kappa) opioid receptor agonist U-50,488H decreased male sexual behavior, locomotor activity, body temperature and bodily grooming, and induced body flattening. The U-50,488H-induced inhibitions of male sexual behavior were prevented by systemic injections of naloxone and by intra-cranial injections of the kappa opioid antagonist nor-binaltorphimine (NBNI). Injections of NBNI to either the ventral tegmental area (VTA) or the nucleus accumbens septi (NAS) increased female-directed behavior, and prevented the U-50,488H-induced decreases in female-directed behavior. Intra-VTA NBNI prevented U-50,488H-induced decreases in the mean number of ejaculations, intra-NAS NBNI prevented U-50,488H-induced increases in copulation latencies. Intra-medial preoptic area (mPOA) injections of NBNI increased female-directed behavior, and attenuated U-50,488H-induced decreases in female-directed behavior as well as U-50,488H-induced increases in both copulation and ejaculation latencies. Injections of NBNI dorsal to the mPOA were ineffective. Two of 26 days following the central injection of NBNI, systemic injections of U-50,488H remained behaviorally ineffective, leaving both sexual behavior and locomotor activity undiminished. These results suggest that the stimulation of central kappa opioid receptors inhibits sexual behavior in the male rat; perhaps endogenous kappa opioid agonists induce sexual refractory periods.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1992

Selective activation of p42 mitogen-activated protein (MAP) kinase in murine B lymphoma cell lines by membrane immunoglobulin cross-linking. Evidence for protein kinase C-independent and -dependent mechanisms of activation.

Cross-linking of membrane immunoglobulin (mIg), the B lymphocyte antigen receptor, with anti-receptor antibodies stimulates tyrosine phosphorylation of a number of proteins, including one of 42 kDa. Proteins with a similar molecular mass are tyrosine-phosphorylated in response to receptor stimulation in other cell types and have been identified as serine/threonine kinases, termed mitogen-activated protein (MAP) kinases or extracellular signal-regulated kinases (ERKs). The MAP kinases constitute a family of related kinases, at least three of which have molecular masses of 40-45 kDa. In this paper we show that mIg cross-linking stimulated the myelin basic protein phosphotransferase activity characteristic of MAP kinase in both mature and immature murine B cell lines. This enzyme activity co-purified on three different columns with a 42 kDa protein that was tyrosine-phosphorylated (pp42) in response to mIg cross-linking and which reacted with a panel of anti-(MAP kinase) antibodies. Although immunoblotting with the anti-(MAP kinase) antibodies showed that these B cell lines expressed both 42 kDa and 44 kDa forms of MAP kinase, only the 42 kDa form was activated and tyrosine-phosphorylated to a significant extent. Activation of protein kinase C (PKC) with phorbol esters also resulted in selective tyrosine phosphorylation and activation of the 42 kDa MAP kinase. This suggested that mIg-induced MAP kinase activation could be due to stimulation of PKC by mIg. However, mIg-stimulated MAP kinase activation and pp42 tyrosine phosphorylation was only partially blocked by a PKC inhibitor, the staurosporine analogue Compound 3. In contrast, Compound 3 completely blocked the ability of phorbol esters to stimulate MAP kinase activity and induce tyrosine phosphorylation of pp42. Thus mIg may activate MAP kinase by both PKC-dependent and -independent mechanisms.

Amino Acid Sequence↗
PubMed1992

The effects of lesions of the habenular nuclei on the development of sensitization to the behavioral activational effects of repeatedly administered morphine in the rat.

The effects of lesions of the habenular nuclei on the development of sensitization to the behavioral activational effects of morphine (MOR), administered repeatedly either systemically or directly into the ventral tegmental area (VTA) were examined. Lesions of the habenular nuclei blocked the early-appearing sedative effects and enhanced the later-appearing locomotor activational effects seen after systemic injections of MOR (10 mg/kg, i.p.). Habenular lesions did not potentiate the development of sensitization to the locomotor-activational effects seen with the repeated, systemic administration of MOR. The bilateral injection of MOR (5.0 micrograms/0.5 microliter/side) directly into the VTA of animals with habenular lesions resulted in the performance of stereotyped behaviors that appeared as early as the second MOR exposure and remained at high levels with repeated MOR treatment. The stereotyped behavior shown by lesioned animals did not appear to interfere with the acute locomotor activational effects of intra-VTA MOR nor the development of sensitization to these effects when it was administered repeatedly. These results are in agreement with previous research suggesting that by disinhibiting the dopamine (DA) systems, habenular lesions enhance the acute behavioral activational effects of MOR. The results also suggest that the habenular nuclei do not control the changes in the response of the DA systems underlying the development of sensitization to the locomotor-activating effects of MOR when administered repeatedly.

Analysis of Variance↗