Pediatric emergency care: an annotated bibliography of the recent literature.
Explore the source record for details and available documents.
Critical Care↗
Biomedical subjects
J S Walker
Publications and source records attributed to J S Walker.
Pharmacokinetic-pharmacodynamic relationships of morphine in neonates.
Morphine pharmacokinetics and pharmacodynamics (analgesia and sedation) were evaluated after continuous intravenous infusion of morphine in 19 neonates, both preterm and term, whose lungs were ventilated to relieve respiratory distress. Elimination half-life, total plasma clearance, and volume of distribution (mean +/- SD) were 9.6 +/- 3.0 hours, 2.55 +/- 1.65 ml/min/kg (area analysis) or 2.09 +/- 1.19 ml/min/kg (steady-state data), and 2.05 +/- 1.05 L/kg, respectively, and were not significantly different in preterm and term neonates. In neonates with adverse effects of morphine, the plasma clearance was decreased twofold. Mean morphine concentration required to produce adequate sedation in 50% of patients was found to be 125 ng/ml, but concentrations above 300 ng/ml may be associated with adverse effects of morphine. Morphine-6-glucuronide was not detected in the plasma of any neonate, which may explain why neonates require high plasma concentrations of unchanged morphine for sedation.
Female↗
Prophylactic oral antibiotics for low-risk dog bite wounds.
The use of prophylactic antibiotics in the initial treatment of noninfected dog bite wounds is controversial. All patients with noninfected dog bite wounds who presented to our emergency department (ED) over a two-year period were considered for entry into a randomized prospective study. Patients were excluded from the study if they had any high-risk criteria for infection: puncture wounds, hand or foot wounds, wounds greater than 12 hours old, a history of immunocompromising disorders, or the use of immunosuppressive drugs. Patients in the antibiotic group (n = 89) were treated with local wound care and given either dicloxacillin, cephalexin, or erythromycin orally for seven days. Patients in the control group (n = 96) received local wound care only. All patients had their wounds irrigated with a 1% povidone-iodine solution and debrided and sutured if clinically indicated. All patients were subsequently reevaluated for clinical signs of wound infection. The groups were similar in age, sex, time of delay in seeking treatment, anatomic sites of wounds, depths and types of wounds, and number of wounds requiring suturing. The wound infection rates for the antibiotic and control groups were 1.1 and 5.1%, respectively. This difference was not significant (P = 0.212). There were 36 wounds in the antibiotic group and 37 wounds in the control group that were full thickness. The infection rates for these wounds were 2.8 and 13.5%, respectively. This was not statistically significant (P = 0.132). This study suggests that prophylactic oral antibiotics in low-risk dog bite wounds are not indicated.
Administration, Oral↗
Kinetics of drug action in disease states. XXXVIII: Effect of body temperature on the convulsant activity of pentylenetetrazol in rats.
The purpose of this investigation was to determine the effect of body temperature on the pharmacodynamics (convulsant activity) of pentylenetetrazol (PTZ). Rats received an iv infusion of PTZ until the onset of maximal seizures, at which time samples of cerebrospinal fluid (CSF), brain, and blood (for serum) were obtained for subsequent determination of PTZ concentrations by HPLC. The PTZ infusion caused a decrease in body temperature of approximately 4 degrees C within 20 min and onset of seizures in approximately 40 min. Compared with animals whose temperature was maintained in the normal range by heating pads, the hypothermic rats required significantly larger doses and higher serum, brain, and CSF concentrations of PTZ to produce seizures. Other rats received an injection of brewer's yeast to produce fever. Then, PTZ was infused 6, 12, or 24 h later when body temperature was elevated by an average of 1.3, 1.1, or 0.4 degrees C, respectively. Compared with control rats, whose temperature was maintained in the normal range by heating pads, moderate hyperthermia had no significant effect on the dose and concentrations of PTZ required to produce maximum seizures. Pentylenetetrazol exemplifies a drug that can produce hypothermia which, in turn, reduces the sensitivity of rats to its pharmacologic action. Unlike the central nervous system (CNS) depressants phenobarbital and ethanol, whose pharmacologic activity in rats is enhanced at elevated body temperature, the activity of the CNS stimulant PTZ is apparently not altered by fever.
Animals↗
Pediatric emergency care: an annotated bibliography of the recent literature.
Explore the source record for details and available documents.
Child↗
Pediatric emergency care: an annotated bibliography of the recent literature.
Explore the source record for details and available documents.
Emergency Medicine↗
Self-administered intraurethral chlorpromazine: an unusual cause of priapism.
Priapism is a prolonged, painful penile erection unaccompanied by sexual desire and not alleviated by ejaculation. The etiologies of priapism are numerous and diverse. Priapism can be a serious adverse effect of psychotropic medications. The case of a 36-year-old man who demonstrated priapism, 48 hours after inserting a crushed chlorpromazine tablet into the urethral meatus of his penis, is reported. Priapism induced by this route of drug administration has not been previously described. The pathophysiology and treatment of priapism are reviewed.
Adult↗
Effect of multiple dosing on the analgesic action of diflunisal in rats.
This investigation was designed to compare the analgesic effect of the initial dose of a repetitively dosed non-narcotic analgesic with the analgesic effect of a subsequent dose given 3 days later. To exclude gradual drug accumulation as a variable, the first ("loading") dose was larger than the maintenance doses. Male Sprague-Dawley rats received 100 mg/kg diflunisal i.v. as the first dose and 70 or 75 mg/kg every 12 hours thereafter. The analgesic effect of the first and seventh doses was determined as the pain threshold (voltage) upon electrical stimulation of the tail every 15 to 30 minutes from the third to the ninth hour after dosing. Blood samples for drug assay were obtained at 3 and 9 hours. A control group received injections of solvent for 6 doses and 100 mg/kg diflunisal as the seventh dose. There were no statistically significant differences between the area under the total or free (unbound) drug concentration versus time curves of the first and seventh dose but the average analgesic effect (area under the voltage increase versus time) of the seventh dose was only 28 percent that of the first dose. The areas under the drug concentration and analgesic effect versus time curves of the diflunisal dose given as the seventh injection to the control rats were similar to those produced by the first dose given to the multiple dosed rats. The results of this investigation show that the analgesic effect of a non-narcotic drug decreases substantially during repeated dosing in an animal model of experimental pain. This change in pharmacologic response has the characteristics of functional rather than pharmacokinetic tolerance in that there was no change in the drug concentration profile with time and no effect of the manipulations as such (i.e., repeated pain threshold determinations and blood withdrawals) on diflunisal-induced analgesia. These observations may have important implications for the evaluation and use of non-narcotic analgesics in the management of clinical pain.
Analgesia↗
Buccal cellulitis.
Buccal cellulitis (BC) is an innocuous appearing infection of the cheek that is found in children and has a high incidence of concomitant bacteremia. Typically, the child is younger than 12 months and has a 2 to 8 hour prodrome of coryza and fever before developing the cellulitis on the cheek. A purplish hue on the cellulitic region is highly suggestive of Hemophilus influenzae bacteremia. The differential diagnosis is reviewed. A complete blood count, blood culture, and cellulitis aspirate culture, should be obtained on all patients with BC. Meningitis may be present despite the lack of meningeal signs. A lumbar puncture should be performed on all children at risk for bacteremic BC. The vast majority of these children are bacteremic and require parenteral antibiotics. A typical case of BC is presented and its management is reviewed.
Amoxicillin↗
Scapular dislocation (locked scapula).
We report the case of a 19-year-old woman who presented to the emergency department with pain and inability to move her right shoulder after falling backwards and striking it on a cart. Radiographs of the shoulder revealed a dislocated scapula. Closed reduction in the ED was successful. This rare case of scapular dislocation serves to emphasize that a heightened awareness for this injury is necessary if it is to be recognized and treated appropriately. Its treatment and prognosis are reviewed.
Adult↗
Smooth muscle energetics: testing theories of crossbridge regulation.
Our results indicate that the kinetic "latch" model of Hai & Murphy is not very sensitive to the proportion of ATP assigned to crossbridges relative to that ascribed to MLC phosphorylation/dephosphorylation. Thus the basis for the relatively low efficiency of smooth muscle, attributed to high MLC phosphorylation/dephosphorylation in this model, remains open to question. Moreover, this model, or any model with mixed populations of crossbridges with differing cycle rates and/or high MLC phosphorylation/dephosphorylation rates is unlikely to account for the observed linearity of JATP and stress reported for many smooth muscles. Our studies comparing the heat production of intact and skinned smooth muscle indicate that the ATPase associated with myosin phosphorylation/dephosphorylation is unlikely to be a major factor in the tension cost of intact smooth muscle. Thus it would appear that energetics places considerable constraints on current theories of crossbridge regulation. Our modelling (Paul, 1989) suggests that it may be time to reevaluate Bozler's original hypothesis that a high attachment:detachment rate ratio for smooth muscle actin-myosin interaction may be sufficient to explain the energetics of smooth muscle.
Adenosine Triphosphate↗
The controversy over radiation safety. A historical overview.
The hazards of ionizing radiation have aroused concern since a short time after the discovery of x-rays and natural radioactivity in the 1890s. Misuse of x-rays and radium prompted efforts to encourage radiation safety and to set limits on exposure, culminating in the first recommended "tolerance doses" in 1934. After World War II, the problems of radiation protection became more complex because of the growing number of people subjected to radiation injury and the creation of radioactive elements that had never existed before the achievement of atomic fission. Judging the hazards of radiation became a matter of spirited controversy. Major public debates over the dangers of radioactive fallout from atmospheric bomb testing in the 1950s and early 1960s and the risks of nuclear power generation in later periods focused attention on the uncertainties about the consequences of exposure to low-level radiation and the difficulties of resolving them.
Environmental Exposure↗
Kinetics of drug action in disease states. XXXII: Effect of experimental hypertension on the pharmacodynamics of phenobarbital in rats.
The purpose of this investigation was to determine the effect of experimental hypertension on the concentrations of phenobarbital required to produce a defined hypnotic effect (loss of righting reflex) in adult, female Lewis rats. Hypertension was induced with deoxycorticosterone acetate (DOCA), administered by im injection (first experiment) or by pellet implant (second experiment), and 1% NaCl in the drinking water. There were two control groups: one that received im injections of water or a drug-free pellet implant plus 1% NaCl in the drinking water, the other that received water injections or drug-free pellet implants and no NaCl in the drinking water. These treatments were carried out for 3 months and resulted in appreciable elevation of blood pressure and increased heart weight in the DOCA + NaCl-treated (but not in the NaCl alone) rats. All animals then received an infusion of phenobarbital until onset of loss of righting reflex. The concentrations of phenobarbital in the serum, serum water, brain, and CSF of the hypertensive rats at the pharmacologic endpoint did not differ significantly from corresponding concentrations in the control groups (except for a marginal difference of the drug concentration in serum water between the DOCA pellet group and the drug-free pellet control group). It is concluded that DOCA-induced hypertension has no apparent effect on the sensitivity of the central nervous system to the hypnotic action of a barbiturate in female rats.
Animals↗
Phenylpropanolamine potentiates caffeine neurotoxicity in rats.
Numerous case reports have documented that phenylpropanolamine (PPA) stimulates the central nervous system with symptoms ranging from anxiety and hallucinations to grand mal seizures produced by overdoses. Most of these reports have occurred following concomitant use of caffeine which in high doses is known to cause seizures and psychotic episodes. The purpose of this investigation was to determine if PPA could potentiate caffeine-induced seizures in the rat. First, the input rate dependence of caffeine-induced neurotoxicity was determined by infusing rats intravenously with caffeine at one of three different rates (1.65-8.12 mg/min) until the onset of maximal seizure. This occurred after an average of 12 to 60 min of infusion. The PPA concentrations in serum, brain, and cerebrospinal fluid (CSF) at this pharmacologic endpoint were independent of infusion rate. In another experiment, rats were pretreated with an anorexiant dose of PPA (30 mg/kg ip) either acutely or chronically for 6 d, while control animals received saline solution. All groups were then infused with caffeine at a rate of 4.18 mg/min until onset of seizures. Caffeine concentrations at that time in serum, brain, and CSF were significantly lower in the PPA-pretreated animals than in the control group. It is concluded that both acute and chronic pretreatment with PPA increases the sensitivity of rats to the neurotoxic effects of caffeine.
Animals↗
Induction of experimental thyroid dysfunction in rats with implantable pellets of thyroxine or propylthiouracil.
Subcutaneously implanted pellets containing the thyroid hormone thyroxine or the thyrotoxic agent propylthiouracil were used to induce hyper- or hypothyroidism in rats. The results obtained were compared to those produced by daily subcutaneous injection of these substances. The thyroxine pellets caused substantial elevation of serum thyroxine concentrations for at least 25 days, whereas the propylthiouracil pellets caused a pronounced decrease of serum thyroxine concentrations. Changes in heart weight and rectal temperature were consistent with the observed alterations of serum thyroxine concentrations. Treatment with propylthiouracil was associated with small elevations of serum total protein, urea nitrogen, and creatine concentrations regardless of the method of administration of this agent. It is concluded that implantable pellets are an effective and convenient means of administering drugs for producing thyroid dysfunction in rats.
Animals↗
Kinetics of drug action in disease states. XXXI. Effect of experimental hyperthyroidism on the hypnotic activity of a benzodiazepine (oxazepam) in rats.
This investigation was designed to determine the effect of experimental hyperthyroidism on the hypnotic activity of a benzodiazepine and on the binding characteristics of the benzodiazepine receptor complex. Rats were made hyperthyroid by subcutaneous implantation of slow release pellets containing L-thyroxine. This treatment produced the characteristic symptoms of hyperthyroidism: increased serum thyroxine concentrations, increased heart weight and body temperature, and decreased serum protein concentrations. The hyperthyroid rats and a parallel group of normal animals (with drug-free pellets implanted subcutaneously) were slowly infused intravenously with oxazepam until they lost their righting reflex. The hyperthyroid rats required a significantly larger dose of the benzodiazepine and their total serum and cerebrospinal fluid concentrations of oxazepam (but not the serum concentration of free drug and the brain concentration) at the onset of loss of the righting reflex were modestly but statistically significantly lower than those of the normal rats. The receptor density and affinity for diazepam in hyperthyroid rats were not significantly different from those of the normal animals. Hyperthyroidism apparently affects the pharmacokinetics of oxazepam but has, at best, only a small effect on the pharmacodynamics (hypnotic activity) of the drug.
Animals↗
Confocal fluorescence microscopy with the tandem scanning light microscope.
Applications of the tandem scanning confocal microscope (TSM) to fluorescence microscopy and its ability to resolve fluorescent biological structures are described. The TSM, in conjunction with a cooled charge-coupled device (cooled CCD) and conventional epifluorescence light source and filter sets, provided high-resolution, confocal data, so that different fluorescent cellular components were distinguished in three dimensions within the same cell. One of the unique features of the TSM is the ability to image fluorochromes excited by ultraviolet light (e.g. Hoechst, DAPI) in addition to fluorescein and rhodamine. Since the illumination is dim, photobleaching is insignificant and prolonged viewing of living specimens is possible. Series of optical sections taken in the Z-axis with the TSM were reproduced as stereo images and three-dimensional reconstructions. These data show that the TSM is potentially a powerful tool in fluorescence microscopy for determining three-dimensional relationships of complex structures within cells labeled with multiple fluorochromes.
Animals↗
Kinetics of drug action in disease states. XXXIV. Effect of experimental thyroid disorders on the pharmacodynamics of phenobarbital, ethanol and pentylenetetrazol.
To determine the effect of thyroid disorders on the concentration-activity relationship of certain drugs acting on the central nervous system, rats were made hyperthyroid by administration of L-thyroxine and hypothyroid by administration of propylthiouracil. They then received a slow i.v. infusion of phenobarbital or ethanol until they lost their righting reflex, or of pentylenetetrazol until the onset of maximal seizures. Drug concentrations in serum, brain and cerebrospinal fluid (CSF) were determined at these pharmacologic endpoints. Hyperthyroidism was associated with a statistically significant increase in the infused hypnotic dose and brain concentration of phenobarbital but had no apparent effect on concentrations of the drug in serum and CSF. The hypnotic dose of ethanol was increased significantly in hyperthyroid rats and decreased in hypothyroid animals; ethanol concentrations in serum, brain and CSF at onset of effect were generally not affected by thyroid dysfunction except for a small but statistically significant increase of serum ethanol concentrations in the hyperthyroid rats. The convulsant dose of pentylenetetrazol was reduced significantly in hypothyroid animals and unaltered in hyperthyroid rats; the concentrations of the convulsant in serum, brain and CSF were not apparently changed by the thyroid dysfunctions. In general, experimental thyroid disorders had no pronounced effect on the pharmacodynamics (concentration-effect relationship) of phenobarbital, ethanol and pentylenetetrazol in rats.
Animals↗