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Biomedical subjects

J P Thompson

Publications and source records attributed to J P Thompson.

At least 37 records · Page 2Linked to original sources
PubMed2000

Comparison of different doses of remifentanil on the cardiovascular response to laryngoscopy and tracheal intubation.

We have compared three bolus and infusion regimens of remifentanil on the cardiovascular response to laryngoscopy and orotracheal intubation in three groups of 20 ASA I-II female patients, in a randomized, double-blind study. Patients in group 1 received glycopyrolate 200 micrograms i.v. followed by a bolus dose of remifentanil 1 microgram kg-1 over 30 s and an infusion of remifentanil at a rate of 0.5 microgram kg-1 min-1. The other patients received remifentanil 0.5 microgram kg-1 over 30 s and an infusion of 0.25 microgram kg-1 min-1 with (group 2) or without (group 3) pretreatment with glycopyrrolate 200 micrograms. All patients then received a sleep dose of propofol, rocuronium 0.6 mg kg-1 and 1% isoflurane with 67% nitrous oxide in oxygen. Laryngoscopy and tracheal intubation were performed 3 min later. Heart rate and arterial pressure were recorded at 1-min intervals from before induction of anaesthesia until 5 min after intubation. Baseline heart rate was similar in all groups, but decreased in group 3 (no glycopyrrolate) after induction and remained significantly lower after intubation compared with the other groups (P < 0.05). Heart rate and arterial pressure increased slightly after intubation in each group but there were no significant differences in mean arterial pressure between groups at any time. The incidence of bradycardia (one patient in group 2) and hypotension (two patients in groups 1 and 2 and three patients in group 3) was low.

Adult↗
PubMed2000

Effect of meloxicam on postoperative pain after abdominal hysterectomy.

We studied 36 patients, allocated randomly to receive meloxicam 15 mg rectally (n = 18) or placebo suppository (n = 18) before total abdominal hysterectomy in a double-blind study. Visual analogue scores for pain at rest (P < 0.005), on movement (P < 0.05) and on coughing (P < 0.05) were significantly decreased in the meloxicam group during the first 24 h after surgery. Mean 24-h PCA morphine requirements were 33.2 (SD 16.9) mg and 38.2 (20.8) mg in the meloxicam and placebo groups, respectively (ns). There was no difference in the incidence of nausea, vomiting or sedation between groups.

Adult↗
PubMed2000

Infiltration of the abdominal wall with local anaesthetic after total abdominal hysterectomy has no opioid-sparing effect.

We have measured the effect of infiltration of the deep and superficial layers of the abdominal wound on morphine consumption and pain for 48 h after operation, in 40 patients undergoing total abdominal hysterectomy, in a double-blind randomized study. Patients received wound infiltration with 0.9% normal saline 40 ml or 40 ml of 0.25% bupivacaine with epinephrine 1:200,000. There were no significant differences between groups in morphine consumption, linear analogue scores for pain at rest or on movement, nausea or sedation during the first 48 h after operation. We conclude that infiltration of the deep and superficial layers of the wound of a Pfannenstiel incision with local anaesthetic solution did not confer additional analgesia in patients undergoing major gynaecological surgery.

Abdominal Muscles↗
PubMed2000

Comparison of ketamine and morphine for analgesia after tonsillectomy in children.

In a double blind study we compared the effects of i.m. ketamine with morphine on postoperative analgesia in children undergoing tonsillectomy. Eighty children (aged 6-15 yr) were randomized to receive either i.m. morphine 0.1-0.15 mg kg-1 or ketamine 0.5-0.6 mg kg-1, after induction of a standard general anaesthetic. Pain scores 30 min after extubation were higher (P < 0.05) in the ketamine group, but were similar thereafter to the morphine group. Mean (SD) times to recovery from anaesthesia were 20.1 (SD 6.5) min in the ketamine group compared to 14.2 (5.6) min in the morphine group (P < 0.01). There were no differences in supplemental analgesia requirements, or the incidence of vomiting or dreaming between the groups. We conclude that ketamine 0.5 mg kg-1 i.m. may be an alternative analgesic for children undergoing tonsillectomy.

Adolescent↗
PubMed2000

Endovascular AAA repair attenuates the inflammatory and renal responses associated with conventional surgery.

PURPOSE: To quantify the inflammatory and renal parameters in comparative cohorts of patients undergoing surgical or endovascular repair of abdominal aortic aneurysms (AAAs). METHODS: Forty-three patients (41 men; ages 58-81 years) underwent endovascular or conventional aneurysm surgery according to aortic morphology. All patients received a standard general anesthetic and had 12 serial blood and urine samples collected during the perioperative period. Samples underwent analysis for the cytokines interleukin (IL) 1beta tumor necrosis factor-alpha (TNF-alpha), and IL-6. White cell and platelet activation were estimated indirectly by measuring sL-selectin and 11-dehydrothromboxane B2, respectively. The urinary albumin:creatinine ratio (ACR) and N-acetyl-beta-D-glucosaminidase (NAG) activity were estimated to assess renal injury. Fibrinogen and fibrinogen degradation products were calculated to assess activation of the clotting cascade. RESULTS: Twenty-three patients underwent endovascular AAA repair and 20 had conventional surgery. Concentrations of IL-6 (p < 0.002) and TNF-alpha (p < 0.0004) were significantly higher in the conventional group. The ACR (p < 0.002) and urinary NAGs (p < 0.0009) were also significantly higher in this group, suggesting greater renal injury. Platelet activity was significantly greater in the endovascular group (p < 0.01), perhaps indicating thrombus organization within the aneurysm sac. CONCLUSIONS: These data suggest that the inflammatory response associated with conventional aneurysm repair is largely obviated by endovascular techniques. This may potentially translate to a lower incidence of multiple organ failure after endovascular surgery.

Acetylglucosaminidase↗
PubMed1999

Mutants of interleukin 13 with altered reactivity toward interleukin 13 receptors.

Interleukin 13 (IL13) belongs to a family of cytokines whose members exhibit structural homology, despite amino acid sequence dissimilarity. For example, while of limited sequence homology, IL13 and IL4 share a signaling receptor, IL13/4 receptor, on a variety of human normal cells. However, a subclass of IL4-independent IL13 receptors is overexpressed on certain transformed cells, including human malignant gliomas. We introduced mutations into human (h) IL13 to determine the site(s) involved in interaction with the shared receptor and/or the glioma-associated receptor. This analysis identified at least three protein regions that are needed for signaling through the shared receptor. These regions were localized to alpha-helices A, C, and D and were mainly separate from the region(s) needed to interact with the glioma-associated receptor. Glutamic acids at positions 13 and 16 in hIL13 alpha-helix A, arginine and serine at positions 66 and 69 in helix C, and arginine at position 109 in helix D were found to be important in inducing biological signaling since their specific mutation resulted in loss and/or gain of function phenomena. We demonstrate that the molecular requirements of hIL13 to interact with its respective receptors are generally distinct and can be controlled by mutagenesis of the cytokine.

Base Sequence↗
PubMed1999

Cardiovascular and catecholamine responses during endovascular and conventional abdominal aortic aneurysm repair.

OBJECTIVES: To compare changes in plasma catecholamines, acid-base status and cardiovascular dynamics in patients undergoing endovascular or conventional infrarenal abdominal aortic aneurysm (AAA) repair under standard general anaesthesia. DESIGN: Prospective cohort study. MATERIALS: 30 patients scheduled for elective infrarenal AAA repair. METHODS: Plasma epinephrine and norepinephrine concentrations, acid-base status and cardiovascular measurement were compared before surgery, and 5 min after aortic clamping and clamp release (conventional group) or occlusion and release (endovascular group) in patients undergoing endovascular (n = 15) or conventional AAA repair (n = 15). RESULTS: Arterial pH (p < 0.005) and base deficit (p < 0.05) increased, and plasma bicarbonate decreased (p < 0.005) during aortic cross-clamping in the conventional group. pH decreased further (p < 0.005), and base deficit and pCO2 increased (both p < 0.005) after clamp release. These changes were significantly greater than during endovascular repair, in whom within-group changes were not statistically significant. Values were similar in the two groups 30 min after reperfusion. Plasma epinephrine concentrations increased during conventional surgery (p < 0.05) and were greater than in the endovascular group (p < 0.05). Plasma norepinephrine concentrations increased during surgery in both groups but the changes were not statistically significant. CONCLUSIONS: Plasma catecholamine concentrations, changes in cardiovascular variables and acid-base status were increased during conventional compared with endovascular AAA repair.

Acid-Base Equilibrium↗
PubMed1999

Nocturnal hypoxaemia and respiratory function after endovascular and conventional abdominal aortic aneurysm repair.

Respiratory function, assessed by pre- and postoperative spirometry, and overnight pulse oximetry recordings, was compared prospectively in patients undergoing infrarenal abdominal aortic aneurysm repair by endovascular or conventional surgery. Episodic hypoxaemia was common in both groups before operation and up to the fifth night after operation. The frequency and severity of hypoxaemia were greater in the conventional group (P < 0.05). FEV1 and FVC decreased significantly on the third and fifth days after operation in both groups (P < 0.05); decreases in FVC were greater in patients undergoing conventional surgery. On the fifth day after operation, FVC had recovered to 86% and 64% of preoperative values in the endovascular and conventional groups, respectively (P < 0.05). Duration of surgery was greater (P < 0.05) and duration of postoperative artificial ventilation significantly less (P < 0.05) after endovascular repair. Postoperative PCA morphine consumption and duration of use were significantly greater (P < 0.05) in patients undergoing conventional abdominal aortic aneurysm surgery.

Aged↗
PubMed1999

Effect of a remifentanil bolus dose on the cardiovascular response to emergence from anaesthesia and tracheal extubation.

We have examined the effect of remifentanil on the haemodynamic response to emergence from anaesthesia and tracheal extubation in 40 ASA I-II female patients undergoing diagnostic laparoscopy, in a randomized, double-blind study. All patients received a standard general anaesthetic comprising propofol, vecuronium and 1% isoflurane with 66% nitrous oxide in oxygen. At the end of surgery, a bolus dose of remifentanil 1 microgram kg-1 (n = 20) or saline placebo (n = 20) was given and tracheal extubation was performed when standard criteria were achieved. Arterial pressure and heart rate were recorded non-invasively at 1-min intervals from the end of surgery. Remifentanil attenuated the increase in both mean arterial pressure (P < 0.001) and heart rate (P < 0.05) at extubation. Mean time to extubation was 7.2 (SEM 0.6) min and 4.0 (0.5) min in the remifentanil and saline groups, respectively (P < 0.001). There was no difference in the incidence of coughing at extubation, time to recovery from anaesthesia or time to fitness for discharge from the recovery room.

Adolescent↗
PubMed1999

Retargeting interleukin 13 for radioimmunodetection and radioimmunotherapy of human high-grade gliomas.

A vast majority of patients with glioblastoma multiforme (GBM), a high-grade glioma, overexpress abundant amounts of a receptor for interleukin (IL)-13 in situ. This receptor is more restrictive because it is IL-4-independent and therefore differs from the IL-13/4 signaling receptor of normal tissue that is shared with IL-4. We previously identified one of the sites on the human IL (hIL)-13 molecule that is important for its interaction with the IL-13/4 receptor, a residue of glutamic acid at position 13. In this study, we mutated the cytokine and produced hIL-13.E13Y, in which the glutamic acid was substituted by tyrosine. This additional tyrosine residue was therefore strategically located within the region of IL-13 interaction with the signaling physiological receptor. hIL-13.E13Y did not transduce signals through the IL-13/4 receptor, whereas its interaction with the more restrictive, GBM-associated receptor remained intact. The mutated hIL-13 could be readily radiolabeled. Radiolabeled hIL-13.E13Y produced specific autoradiographic images of human GBM specimens. We demonstrate an effective way to redirect hIL-13 to its more restrictive receptor found in high-grade gliomas by mutagenizing the cytokine, and, concomitantly, we equipped hIL-13 with an additional tyrosine residue for higher specific activity radiolabeling.

Amino Acid Sequence↗
PubMed1998

Inhibition of the adherence of cholera toxin and the heat-labile enterotoxin of Escherichia coli to cell-surface GM1 by oligosaccharide-derivatized dendrimers.

The adherence of either cholera toxin or the heat-labile enterotoxin of Escherichia coli to monosialoganglioside gal(beta1-3)galNAc(beta1-4)[sialic acid (alpha2-3)]gal(beta1-4)glc(beta)1-ceramide (GM1) present on the surface of epithelial cells lining the intestine is the first step of a series that results in the induction of a watery diarrhea. While cholera is more severe, both can lead to death as a result of dehydration. To determine the potential of defined multivalent oligosaccharides, synthesized by the covalent attachment of multiple phenylisothiocyanate (PITC) derivatives of gal(beta1-3)galNAc(beta1-4)[sialic acid(alpha2-3)]gal(beta1-4)glc (oligo-GM1) to the arms of a poly(propylene imine) dendrimer, as therapeutic agents for these diseases, their ability to inhibit adherence of the toxins to cell surface-associated GM1 was determined. They not only inhibited choleragenoid (binding subunit of cholera toxin) binding to GM1-treated NCTC-2071 cells (chemically transformed murine fibroblasts) at 5 degrees, but also inhibited adherence of the choleragenoid, cholera toxin, and heat-labile enterotoxin of E. coli to GM1-treated NCTC-2071 cells at 37 degrees. Inhibition was observed whether the toxin was preincubated with the oligo-GM1-PITC-derivatized dendrimer prior to addition to cells or given just after the addition of the derivatized dendrimer to cells. The derivatized dendrimer had no effect on cell viability, as monitored by trypan blue exclusion. Blue-shifts in tryptophan fluorescence emission spectra maxima induced by adherence of either choleragenoid, cholera holotoxin, or the heat-labile enterotoxin of E. coli to oligo-GM1-PITC-derivatized dendrimers were similar to those induced by adherence to GM1 or oligo-GM1. Comparable shifts were not observed when the toxins were incubated with gangliosides that fail to function as receptors.

Adhesiveness↗
PubMed1998

Correlations between ultrasonographic findings and specific hepatic diseases in cats: 72 cases (1985-1997).

OBJECTIVE: To identify correlations between ultrasonographic findings and specific hepatic diseases in cats. DESIGN: Retrospective study. SAMPLE POPULATION: Medical records of 72 cats with a histopathologic diagnosis of hepatic disease and diagnostic-quality abdominal ultrasonograms between 1985 and 1997. PROCEDURE: Abdominal ultrasonographic findings in 72 cats with histologically confirmed hepatic disease (hepatic lipidosis excluded) were reviewed. Rather than attempt to combine individual ultrasonographic findings with specific hepatic diseases, 2 classification trees were created as models to correlate certain groups of abnormalities with specific hepatic diseases or with malignant and benign lesions of the liver. Sensitivity and specificity of classification trees were calculated. RESULTS: Use of a classification tree resulted in correct classification of malignant versus benign hepatic lesions in 88.9% of cats that had hepatic disease (sensitivity, 90.7%; specificity, 86.1%). Use of a classification tree to distinguish individual types of hepatic diseases resulted in mostly accurate classification of hepatic lymphosarcoma (sensitivity, 70.5%; specificity, 98.2%), cholangitis-cholangiohepatitis syndrome (sensitivity, 87%; specificity, 90%), and benign lesions of the liver (sensitivity, 84.6%; specificity, 86.4%). Criteria that helped most in differentiating among various hepatic diseases were abnormalities within other organs (spleen, lymph nodes) and appearance of the hepatic portal system. A correlation was not found between focal or multifocal appearance of hepatic lesions and specific hepatic diseases. CLINICAL IMPLICATIONS: Use of classification trees to distinguish among specific hepatic diseases or between malignant and benign hepatic lesions provides potentially useful algorithms for ultrasonographic evaluation of cats with hepatic disease.

Algorithms↗
PubMed1998

Effect of remifentanil on the haemodynamic response to orotracheal intubation.

We have examined the effect of remifentanil on the haemodynamic response to orotracheal intubation in a randomized, double-blind study. We studied 40 patients allocated to one of four groups of 10 each, to receive the following immediately before induction of anaesthesia: remifentanil 1 microgram kg-1 bolus over 30 s, followed by an infusion of 0.5 microgram kg-1 min-1; saline placebo only; glycopyrrolate 200 micrograms and remifentanil 1 microgram kg-1 bolus over 30 s, followed by an infusion of 0.5 microgram kg-1 min-1; or glycopyrrolate 200 micrograms only. Anaesthesia was induced with propofol, vecuronium and 1% isoflurane with 66% nitrous oxide in oxygen. The trachea was intubated under direct laryngoscopy 3 min after induction of anaesthesia. Arterial pressure and heart rate were measured non-invasively, immediately before induction of anaesthesia and then at 1-min intervals. Remifentanil was found to effectively attenuate the pressor response to intubation (P < 0.05 for the increase in mean arterial pressure; P < 0.01 for the increase in heart rate). In the absence of a concurrent vagolytic agent, remifentanil was associated with bradycardia or hypotension, or both, in five of 10 patients, compared with one patient who received remifentanil and glycopyrrolate.

Adolescent↗
PubMed1998

Perioperative pharmacokinetics of transdermal fentanyl in elderly and young adult patients.

The perioperative pharmacokinetics of transdermally-delivered fentanyl were compared in 10 young adult (mean [range] age 32.7, [25-38] yr) and eight elderly (mean [range] age 73.7 [64-82] yr) patients following abdominal surgery. Transdermal fentanyl patches designed to release 50 micrograms h-1 were applied 2 h preoperatively and left in place for 72 h. Plasma fentanyl concentrations were measured by radioimmunoassay during patch application and for 30 h after patch removal. The mean half-time (time for plasma concentrations to double after patch application) was 4.2 h in the younger group and 11.1 h in the elderly group (P < 0.005). Mean maximum plasma concentrations were 1.9 ng ml-1 and 1.5 ng ml-1 in the younger and elderly groups respectively (ns). There were no differences in the time at which maximum plasma concentrations occurred (tmax), elimination half-life after patch removal, or AUC(0-infinity).

Abdomen↗
PubMed1997

Attenuation of B5R mutants of rabbitpox virus in vivo is related to impaired growth and not an enhanced host inflammatory response.

The rabbitpox virus (RPV) B5R protein, synthesized late in infection, is found as a 45-kDa membrane-associated protein of the envelope of infectious extracellular enveloped virus (EEV) and as a 38-kDa protein secreted from the cell by a process independent of morphogenesis. The protein is not found associated with intracellular mature virus (IMV). Deletion of the gene attenuates the virus (RPV delta B5R) in animals (mice and rabbits), has relatively little effect on formation of IMV, prevents EEV formation in some but not all cells, and leads to a reduced host range. Analysis of the sequence of the protein suggests relatedness to factor H of the complement cascade. Collectively, these observations suggest that attenuation of the virus in vivo could be linked to an inhibition of the inflammatory response, a deficiency in growth, or both. In this report we have analyzed the behavior of RPV delta B5R in infected mice and rabbits and conclude that attenuation of the mutant virus likely results from simple failure to grow within the infected animal and that the inflammatory response probably contributes little to the observed attenuation.

Animals↗
PubMed1997

Oligosaccharide-derivatized dendrimers: defined multivalent inhibitors of the adherence of the cholera toxin B subunit and the heat labile enterotoxin of E. coli to GM1.

Poly(propylene imine) dendrimers having four or eight primary amino groups and a Starburst (PAMAM) dendrimer having eight primary amino groups were used as core molecules, to which phenylisothiocyanate derivatized (PITC) galbeta1-3galNAcbeta1-4[sialic acid alpha2-3]-galbeta1-4glc (oligo-GM1) residues were covalently attached to yield multivalent oligosaccharides. The synthesis of the oligo-GM1-PITC derivatized dendrimers was monitored using high performance thin layer chromatography, infrared spectroscopy, sialic acid content, and mass spectroscopy. The ability of multivalent oligo-GM1-PITC dendrimers to inhibit the binding of 125I-labeled cholera toxin B subunit and the heat labile enterotoxin of E. coli to GM1-coated microtiter wells was determined. IC50s obtained for the oligo-GM1-PITC dendrimers, GM1, and the oligosaccharide moiety of GM1 indicated that the derivatized dendrimers inhibited binding of the choleragenoid and the heat labile enterotoxin to GM1-coated wells at a molar concentration five- to 15-fold lower than native GM1 and more than 1,000-fold lower than that of the free oligosaccharide.

Animals↗
PubMed1997

The cardiovascular responses to double lumen endobronchial intubation and the effect of esmolol.

The cardiovascular responses to double lumen endobronchial intubation and the effect of esmolol were examined in two groups of 10 ASA 2 & 3 patients undergoing pulmonary surgery in a double blind, placebo-controlled study. Endobronchial intubation was associated with a significant increase in arterial pressure and heart rate (p = 0.004), and a significant increase in plasma noradrenaline concentrations (p < 0.01) in the control group. The haemodynamic changes were smaller (p < 0.001) in the patients who received esmolol compared with the changes in the the control group. The increase in plasma noradrenaline concentrations was significantly greater (p < 0.05) in the esmolol group. The pressor response to endobronchial intubation in this study was of a similar magnitude to that known to occur in response to tracheal intubation.

Adrenergic beta-Antagonists↗