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Biomedical subjects

J E Cannon

Publications and source records attributed to J E Cannon.

At least 19 recordsLinked to original sources
PubMed1996

Growth and fresh meat quality characteristics of pigs supplemented with vitamin E.

Crossbred pigs (n = 30) were fed to determine the influence of supplementation with vitamin E on growth and slaughter characteristics of swine and on the quality characteristics of fresh pork. Pigs received either a control diet containing no vitamin E (CON) or a diet formulated to contain 100 mg of vitamin E/kg feed (VITE). During 84 d of feeding, feed intake and weight gain were measured every 2 wk. After the feeding period, pigs were slaughtered and the loin from the left side of each carcass was removed 4 d after death. Alpha-Tocopherol concentration and proximate composition of the longissimus muscle were determined. Loins were sliced into 10-cm sections and stored under vacuum (2 degrees C) for 0, 14, 28, and 56 d. After storage, loins were sliced into 2.54-cm chops, wrapped in polyvinyl chloride film and stored in a retail case (2 to 4 degrees C) for 5 d. Thiobarbituric acid (TBA) values, Hunter L, a, and b values, total plate counts, pH, purge loss, drip loss, cook loss, taste panel characteristics, and visual panel characteristics were evaluated. Growth traits, slaughter characteristics, and proximate composition did not differ (P > .05) between dietary treatment groups. Alpha-Tocopherol concentrations were greater (P < .05) and TBA values during extended retail display were less (P < .05) for VITE chops than for CON chops. Overall palatability ratings were more desirable (P < .05, at 14 d of vacuum storage) for VITE chops than for CON chops. Color measurements, sensory characteristics, total plate counts, pH, purge loss, drip loss, and cook loss were not influenced (P > .05) by vitamin E supplementation. These results indicated that at the tissue alpha-tocopherol concentrations of the present study, vitamin E supplementation of the growing-finishing diet of hogs reduced lipid oxidation in fresh pork but did not influence pork color or tissue drip loss.

Analysis of Variance↗
PubMed1996

Effect of ractopamine on growth performance, carcass composition, and cutting yields of pigs slaughtered at 107 and 125 kilograms.

At approximately 68 kg live weight, crossbred barrows and gilts (n = 144) were allocated to be fed to one of two weight end points (107 kg and 125 kg). Pigs from each weight group were treated with Ractopamine (RAC) (0, 10, or 20 ppm; n = 24/ treatment for the last 40 kg of gain. Feed consumption and weight gain were measured. Pigs were slaughtered and carcass measurements made at 24 h postmortem. Carcasses were fabricated into wholesale, trimmed wholesale, and boneless wholesale cuts for cutting yields. Hams were separated into muscle, fat, and bone. The RAC improved growth characteristics and carcass characteristics. Pigs fed RAC had increased (P < .01) average daily gain and improved (P < .01) feed:gain ratio over controls in each weight group. Carcasses from pigs treated with RAC had larger (P < .01) longissimus muscle area and reduced (P < .01) fat at the 10th rib. Cuts from 125-kg pigs were generally heavier than those from 107-kg pigs. The RAC increased (P < .05) the boneless cut weights of both weight groups. Percentage of dissected lean from the hams of RAC-treated pigs was (P < .05) higher than that of controls. Few consistent differences were observed between the 10 and 20 ppm of RAC treatments. Results from this study indicate that RAC had positive effects on the growth characteristics, carcass characteristics, and carcass cutting yields of pigs representative of the broad spectrum of market weights.

Adrenergic beta-Agonists↗
PubMed1994

Precurarization.

Explore the source record for details and available documents.

Calcium↗
PubMed1992

Effects of diet containing extruded full-fat soybeans or butter on the growth, composition, and sensory characteristics of pork.

Ninety-six crossbred barrows were randomly allotted to five replications of four treatments to determine the effects of diets containing 20% extruded full-fat soybeans (FFS) or 4% butter (B) on the growth, composition, and sensory characteristics of finishing pigs. Pigs were housed five per pen, except for one replication that had four pigs per pen, in environmentally regulated barns. Pigs were given ad libitum access to a corn-soybean meal diet for 11 wk (control); a corn-extruded soybeans and soft wheat midds diet for 11 wk (FFS-11); a corn-soybean meal diet for 6 wk, changed to a corn-extruded soybeans and soft wheat midds diet for 5 wk (FFS-5); or a corn-soybean meal diet for 6 wk, changed to a corn-soybean meal, soft wheat midds, and 4% butter diet for 5 wk (B). Feed intake and weight gain were measured once every 2 wk. Pigs were slaughtered and carcass data were collected. Sensory characteristics (tenderness, juiciness, pork flavor intensity, off-flavor intensity, and overall acceptability), shear force, moisture, and fat content were determined for the longissimus muscle. Sensory characteristics (pork flavor, off-flavor, rubbery, cohesiveness, and juiciness) and 2- thiobarbituric acid values were determined for ground pork (30% fat) after 1, 4, and 7 d for control, FFS-11, and B treatments. No differences (P > .05) in ADG were observed between diets. Feed efficiency of the FFS-11 group was better (P < .05) than that of the control or B groups. No consistent differences were observed for carcass, sensory, or shear-force characteristics of the longissimus muscle or ground pork.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1991

Pneumocephalus following attempted epidural anaesthesia.

This report describes iatrogenic pneumocephalus in an obstetrical patient following attempted epidural anaesthesia using the loss of resistance technique. On the fourth attempt at epidural injection, an apparent loss of resistance was identified and 5 ml air was injected. The patient complained immediately of severe bifrontal headache followed by emesis. The baby was eventually delivered by Caesarean section, with general anaesthesia and avoiding nitrous oxide. The patient's headache resolved within 24 hr without further sequelae.

Adult↗
PubMed1989

Atracurium, vecuronium, and pancuronium do not alter the minimum alveolar concentration of halothane in humans.

The authors studied 64 unpremedicated, healthy surgical patients, aged 42 +/- 14 yr, to determine the effects of atracurium, vecuronium, and pancuronium on the minimum alveolar concentration (MAC) of halothane. Anesthesia was induced using halothane/nitrous oxide/oxygen via a mask without the administration of other drugs. Nitrous oxide was discontinued, the trachea was intubated without prior administration of neuromuscular blocking drugs, and anesthesia was maintained with halothane in oxygen. Participating patients were assigned to one of five groups: 1) no neuromuscular blocking drug (control group, n = 9); 2) atracurium 0.5 mg/kg (n = 10); 3) atracurium 1.0 mg/kg (n = 15); 4) vecuronium 0.1 mg/kg (n = 20); or, 5) pancuronium 0.1 mg/kg (n = 10). Tourniquets, inflated to 300 mmHg immediately before iv administration of neuromuscular blocking drug and 15-30 min prior to skin incision, were used to isolate extremities from circulating neuromuscular blocking drug in all patients. A positive response to stimulation was defined as movement of at least one extremity occurring distal to the tourniquet within 1 min following skin incision. The first patients in the control and atracurium groups were studied at an end-tidal halothane concentration of 0.95%. The first patient in the pancuronium group was studied at a halothane concentration of 0.75%, and the first patient in the vecuronium group at 0.70%. Subsequent patients were studied at end-tidal halothane concentrations 0.10% above or below that of the preceding patient, depending on the presence or absence of movement with skin incision. Control MAC for halothane was 0.74% +/- 0.09% (mean +/- SEM).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Large doses of vecuronium and plasma histamine concentrations.

The authors studied 20 surgical patients to determine the effect of large doses of vecuronium on plasma histamine concentrations. Patients were unpremedicated and anaesthetized with nitrous oxide and halothane via a mask. Tracheal intubation was performed without the use of muscle relaxants. Fifteen min later and before surgery had begun, vecuronium, in doses of 0.1 and 0.2 mg.kg-1 (n = 10 for each dose), was administered as an IV bolus. Arterial blood samples were obtained prior to and 2, 5, and 10 min after vecuronium administration and analyzed for plasma histamine by a radioenzymatic method. Arterial blood pressure and heart rate were measured continuously. In one patient who received 0.1 mg.kg-1 of vecuronium, plasma histamine concentrations at 2 min were 275 per cent of the control histamine value but fell below control at 10 min. This increase in plasma histamine was not associated with clinically important changes in blood pressure or heart rate. As a group, study patients had no significant changes in plasma histamine concentrations with either dose of vecuronium. In addition, mean plasma histamine values for each sampling interval did not differ between the two patient groups. Mean arterial blood pressure (MAP) decreased significantly at 10 min in patients receiving vecuronium 0.1 mg.kg-1, and at 2 and 10 min in patients receiving 0.2 mg.kg-1 of vecuronium. However, these decreases in MAP were not clinically important. Changes in plasma histamine concentrations did not correlate with corresponding changes in MAP. Heart rate did not change significantly in any patient during the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Vecuronium inhibits histamine N-methyltransferase.

Although there have been clinical reports of significant hypotension and flushing associated with the use of vecuronium, it produces minimal cardiovascular effects in the vast majority of patients. In addition, there is no evidence that vecuronium stimulates the release of histamine. The authors performed in vitro kinetic studies to determine the effect of vecuronium on histamine N-methyltransferase (HNMT), the primary catabolic enzyme for histamine in humans. They also examined plasma from patients who had received vecuronium (0.1 or 0.2 mg/kg) to determine whether clinically used concentrations of the drug could inhibit HNMT. It was determined that vecuronium is a strong inhibitor of HNMT; apparent Ki = 1 microM. The inhibition is competitive with respect to methyl-donor and noncompetitive with respect to histamine. Vecuronium, in doses greater than or equal to 0.1 mg/kg, may delay the metabolism of histamine by HNMT in vitro.

Histamine N-Methyltransferase↗
PubMed1987

Continuous infusion of vecuronium: the effect of anesthetic agents.

The authors studied the effects of enflurane, isoflurane, and fentanyl, each in combination with 60% nitrous oxide, on the vecuronium infusion rate necessary to maintain constant 90% depression of control muscle twitch tension. Thirty healthy surgical patients were given an initial 0.1 mg/kg bolus of vecuronium, followed by an infusion of vecuronium at an initial rate of 1.0 microgram . kg-1 . min-1. After 1 h of steady-state 90% twitch depression, plasma vecuronium concentrations (Css90) were measured by capillary column gas chromatography. Total plasma clearance of vecuronium was estimated using Css90 values. Vecuronium infusion rates (mean +/- SD) were similar for patients given enflurane (0.28 +/- 0.13 microgram . kg-1 . min-1) and isoflurane (0.30 +/- 0.13 microgram . kg-1 . min-1), but significantly higher in patients given fentanyl (0.92 +/- 0.37 microgram . kg-1 . min-1). Values for Css90 in the patients receiving enflurane and isoflurane were similar (71 +/- 34 and 72 +/- 44 ng/ml, respectively), but significantly higher in those receiving fentanyl (165 +/- 48 ng/ml). Total plasma clearance was similar during enflurane, isoflurane, and fentanyl anesthesia (4.4 +/- 2.6, 4.6 +/- 1.2, and 5.6 +/- 1.9 ml X kg-1 min-1, respectively). The authors conclude that patients receiving isoflurane and enflurane require markedly lower vecuronium infusion rates to achieve 90% neuromuscular blockade than those receiving fentanyl. The enhancement of neuromuscular blockade by isoflurane and enflurane represents a change in the pharmacodynamics of vecuronium-induced neuromuscular blockade, rather than a change in pharmacokinetics.

Anesthetics↗
PubMed1986

Fentanyl oxygen anaesthesia for abdominal aortic surgery.

Patients who present for abdominal aortic surgery often have significant atherosclerotic disease which may involve the coronary arteries. Haemodynamic responses occurring during fentanyl (100 micrograms X kg-1) oxygen anaesthesia for abdominal aortic surgery were studied in 16 patients. Anaesthesia was induced with fentanyl 100 micrograms X kg-1 with no supplemental doses and metocurine-pancuronium mixture (4:1). In 13 of 16 patients hyperdynamic circulatory responses to surgical stimuli required treatment prior to aortic cross-clamping. Interventions instituted were sodium nitroprusside or nitroglycerin (n = 13), propranolol (n = 4), and diazepam (n = 4). The serum fentanyl concentration at time of response to surgical stimulus was 18.5 +/- 5.6 ng X ml-1 (range 7-27 ng X ml-1; time from induction 71 +/- 49 min, n = 9). Eleven of the 16 patients required treatment for postoperative hypertension. Five of the 16 patients developed myocardial ischaemia, defined as ST segment depression greater than 0.1 mV, at some time during the operative procedure. Unsupplemented fentanyl anaesthesia (100 micrograms X kg-1) was unable to maintain a hypodynamic circulation in patients having abdominal aortic operations.

Aged↗
PubMed1986

Pharmacokinetics of fentanyl in patients undergoing abdominal aortic surgery.

The authors determined the pharmacokinetics of fentanyl 100 micrograms X kg-1 iv in patients undergoing elective abdominal aortic surgery. The mean (+/- SD) age of the ten patients was 67.2 +/- 8.7 yr; their mean weight was 78.5 +/- 13.7 kg. Seven patients had aortic aneurysm repair, and the other three patients had aortobifemoral grafts. Serum fentanyl concentrations were determined from samples drawn at increasing intervals over a 24-h period. A three-compartment pharmacokinetic model was fit to the concentration versus time data. Total drug clearance was 9.8 +/- 1.8 ml X min-1 X kg-1. The volume of distribution at steady-state (Vdss) was 5.4 +/- 1.9 X 1 kg-1. Elimination half-time was 8.7 +/- 2.5 h. There were no significant correlations between these pharmacokinetic parameters and patient's age, duration of aortic cross-clamping, duration of surgery, intraoperative blood loss, or volume of iv fluids given intraoperatively. In healthy volunteers or patients undergoing general surgery, other investigators report mean elimination half-times for fentanyl ranging from 1.7 to 4.4 h. The prolonged elimination half-time in patients having abdominal aortic surgery has important clinical implications. In particular, recovery from large doses will take much longer than would have been anticipated from previously published fentanyl pharmacokinetic data.

Aged↗