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Biomedical subjects

D A Powell

Publications and source records attributed to D A Powell.

At least 109 records · Page 6Linked to original sources
PubMed1986

Nausea and vomiting possibly associated with intravenous acyclovir.

Nausea and vomiting have not been clearly associated with parenteral acyclovir. We report a pediatric patient who developed nausea and vomiting apparently associated with intravenous acyclovir therapy. The child received acyclovir (1500 mg/m2/d) for treatment of recurrent varicella zoster with possible dissemination. Nausea and vomiting could be attributed only to acyclovir therapy. Discontinuing the drug resulted in a resolution of the adverse symptoms. Adverse effects of parenteral acyclovir can mimic the early manifestations of Reye's syndrome, which is an important consideration in children with viral infections. It is necessary to distinguish the cause of nausea and vomiting for proper management of patients.

Acyclovir↗
PubMed1986

Management of pediatric patients with bacterial meningitis in the emergency department.

The pattern and appropriateness of the use of antibiotics, fluids, and laboratory data in the emergency department were evaluated in 50 pediatric patients with meningitis due to Hemophilus influenzae, type b. Results indicate that the quality of care in emergency departments for patients with bacterial meningitis can be improved by administering appropriate antibiotic doses; minimizing the delay in administration of antibiotics; and avoiding the excess fluid administration to decrease the potential for hyponatremia and cerebral edema.

Ampicillin↗
PubMed1985

Cefuroxime therapy for bacteremic soft-tissue infections in children.

Although it is used extensively in Europe, there is a limited amount of published data concerning pediatric clinical experience with cefuroxime in the United States. Thirty-six children, ranging from 3.5 to 57 months of age, received intravenous cefuroxime (75 mg/kg/day in three divided doses) for soft-tissue infections of the face or epiglottis. Infections treated included preseptal (19 patients) and buccal (13 patients) cellulitis and epiglottitis (four patients). Blood cultures were positive in 22 patients, yielding Haemophilus influenzae type b in 17 (four were beta-lactamase-positive), Streptococcus pneumoniae in four; and beta-lactamase-positive, nontypable H influenzae in one. An additional five patients with buccal cellulitis had negative blood cultures but H influenzae type b antigenuria. A satisfactory clinical response was noted in all patients, and repeated blood cultures performed in initially bacteremic patients were sterile. Cefuroxime therapy was well tolerated, and abnormal laboratory results were infrequent, except for absolute granulocytopenia (granulocytes, less than 1,500/cu mm), which occurred in six patients but could not be ascribed to a drug effect because of the uncontrolled design of our study. Treatment with cefuroxime appears to be a safe and effective therapy for pediatric soft-tissue infections due to H influenzae and S pneumoniae.

Cefuroxime↗
PubMed1985

Intraseptal scopolamine has differential effects on Pavlovian eye blink and heart rate conditioning.

The effects of intraseptal scopolamine hydrobromide injections on Pavlovian (classical) conditioning were evaluated, with tones used as the conditioned stimulus (CS) and a periorbital electric shock train as the unconditioned stimulus (UCS). Eye blink (EB) and heart rate (HR) conditioned responses were concomitantly recorded. Although injections of scopolamine into the medial septum impaired the acquisition of the Pavlovian conditioned eyelid reflex, these injections enhanced the magnitude of accompanying Pavlovian conditioned HR decelerations. However, scopolamine applied to the lateral septal area had no effect on EB conditioning, relative to the vehicle, but, like medial injections, enhanced the magnitude of the accompanying HR decelerations. These results are compatible with those of previous investigations: Medial septal dysfunction impairs somatomotor conditioning but leaves autonomic conditioning intact, and septal dysfunction produces a parasympathetic bias of the cardiovascular system.

Animals↗
PubMed1985

Physical health correlates of attitudes toward aging in the elderly.

Attitudes toward aging were assessed in three groups of elderly men (age 65-85), including: hospitalized veterans, veteran outpatients, and a group of non-hospitalized "healthy" veteran volunteers, using the Rosencranz and McNevin Semantic Differential Scale. Social objects rated included an "old man", a "young man", and the participant, himself, ("self"). Attitudes toward "old men" were significantly more negative than attitudes toward "young men" in all three groups. In addition, significant group by "object-rated" interactions were obtained on the autonomous/dependent and instrumental/ineffective dimensions of this scale. These interactions were attributable to a more negative "self" rating by the hospitalized group. These results suggest that within the population studied, older persons in poor health tend to view themselves more like the stereotyped "old person" than do healthy old people, who tend to perceive themselves as being more like a "young person".

Aged↗
PubMed1985

Variation in prophylactic antibiotic use in pediatric orthopedic surgery.

Fifty-two pediatric patients undergoing orthopedic surgery were evaluated to determine the pattern of prophylactic antibiotic use. Of the 50 patients receiving antibiotics, 43 patients were given the antibiotic prior to surgery; 38 patients received the drug within two hours prior to surgery. All patients received the postoperative antibiotic for a duration ranging from 2 to 14 days. Thirty-one patients received the postoperative antibiotic for longer than 48 hours without documentation of infection. Cephapirin and/or cefazolin were the most common antibiotics used. Due to fixed postoperative doses (0.5-2 g), the dose/kg/d exceeded the maximum recommended therapeutic doses in one-third of the patients. The results of this study illustrate that the use of prophylactic antibiotics in pediatric orthopedic surgery can be improved to maximize benefits and minimize costs and the potential for adverse effects. Until data from controlled studies become available, it seems appropriate to follow the Centers for Disease Control guidelines in establishing hospital policy for surgical prophylaxis.

Adolescent↗
PubMed1984

Intrapatient variation in tobramycin kinetics in low birth weight infants during first postnatal week.

Nineteen newborn infants receiving tobramycin, 2.5 mg/kg every 12 h were studied on two occasions at steady-state during the first week of postnatal age. The two studies were separated by two to four days. Total body clearance of tobramycin averaged 1.15 and 1.14 ml/min/kg (p greater than 0.05), apparent volume of distribution averaged 0.82 and 0.68 l/kg (p greater than 0.05), and elimination half-life averaged 8.6 and 7.1 h (p greater than 0.05), during the first and second study, respectively. When the data were further analyzed based on the birth weight, tobramycin kinetics changed during the second study compared to the first study in very low birth weight infants. In eight infants less than or equal to 1.5 kg birth weight, although total clearance of tobramycin was similar, the average apparent volume of distribution decreased from 1.04 l/kg during the first study to 0.73 l/kg during the second study (p less than 0.05) and elimination half-life from 11.1 h during the first study to 8.7 h during the second study (p less than 0.05). These data indicate that these infants may require a change in dosing interval with continued tobramycin therapy during the first week of postnatal age. Intrapatient variation in tobramycin kinetics should be considered, in addition to the interpatient variation reported previously, when monitoring the serum concentration to individualize tobramycin therapy in newborn infants less than or equal to 1.5 kg birth weight.

Female↗
PubMed1984

Age-related changes in Pavlovian conditioning: central nervous system correlates.

Two groups of New Zealand Albino rabbits, average age 6 and 40 months, were subjected to Pavlovian conditioning in which eyeblink (EB) and heart rate (HR) responses were assessed. At the end of conditioning biogenic amine content was assessed in several brain areas; dopamine receptor binding was assessed in caudate nucleus. Older animals revealed an impairment in EB conditioning relative to the young animals; the conditioned decelerative HR response was increased in magnitude in the old animals. Significant deficits in cortical norepinephrine and serotonin were observed in the old subjects, but in both old and young animals the magnitude of the bradycardia was positively correlated with forebrain norepinephrine and inversely correlated with serotonin concentration. Receptor binding experiments revealed that 3H-spiroperidol receptor density was decreased in caudate nuclei of old animals; however, receptor affinity was unaffected by age.

Aging↗
PubMed1984

3H-2-deoxyglucose uptake after electrical stimulation of cardioactive sites in anterior medial cortex in rabbits.

The anterior medial cortex is an important integrative area for cardiovascular adjustments occurring during learning and conditioning. The autoradiographic 3H-2-deoxyglucose (3H-2DG) method for regional cerebral metabolic activity was used to identify other forebrain regions associated with cardiovascular adjustments elicited by electrical stimulation of anterior medial cortex. Rabbits that received anterior midline stimulation that produced bradycardia and depressor responses showed increased metabolic activity in the ipsilateral mediodorsal (MD) nucleus of the thalamus and the dorsal aspect of the claustrum. Two additional animals with anterior cortical placements in the infralimbic and anterior limbic areas showed ipsilateral increased activity in perirhinal cortex, but more dorsolateral placements in the precentral agranular area did not produce increased perirhinal activity. Control animals did not show this pattern of activity. These data suggest that MD and claustrum participate in a neural circuit which mediates cardiovascular adjustments similar to those elicited by Pavlovian conditioning contingencies.

Animals↗
PubMed1984

Broviac catheter-related Malassezia furfur sepsis in five infants receiving intravenous fat emulsions.

Malassezia furfur, a lipophilic fungus commonly found on the skin of healthy adult, was isolated from Broviac catheter blood cultures in five sick infants who were receiving fat emulsions intravenously. The most common manifestations of sepsis included apnea and bradycardia, low-grade fever, interstitial pneumonia, elevated neutrophil band counts, and thrombocytopenia. All infants recovered without antifungal therapy after removal of the Broviac catheters. Early onset of fungemia after catheter placement in these five infants and the recovery of M. furfur from the skin of nearly 33% of hospitalized premature neonates indicate that contamination of the Broviac catheter at time of placement may be the most likely origin of infection.

Catheters, Indwelling↗
PubMed1984

A comparison of physical health and psychosocial variables as predictors of reaction time and serial learning performance in elderly men.

Choice reaction time and serial learning tasks were studied in three groups of elderly men (aged 65 to 85), including (a) hospitalized veterans, (b) veteran outpatients, and (c) nonhospitalized veteran volunteers. Demographic variables, life satisfaction, and attitudes toward aging, as well as objective and subjective measures of physical impairment, were assessed in each group. The three groups differed on both reaction time and serial learning measures. Multivariate analysis revealed that objective physical health assessments were the best predictors of reaction time performance, whereas subjective assessments best predicted serial learning performance. More negative attitudes and life satisfaction were associated with impaired physical health, but these psychosocial measures were poor predictors of behavioral performance.

Aged↗
PubMed1984

Effect of gestational age and birth weight on tobramycin kinetics in newborn infants.

The effects of gestational age and birth weight on tobramycin kinetics were studied in 26 newborn infants with presumed or proven bacterial sepsis during the first week of postnatal age. The infants received tobramycin, 2.5 mg/kg intravenously every 12 h. Group A consisted of nine patients 28 to 30 weeks of gestational age; group B had 11 patients greater than 30 to less than or equal to 34 weeks of gestational age; and group C had six patients greater than 34 to less than or equal to 40 weeks of gestational age. Steady-state peak serum concentrations of tobramycin averaged 6.5, 7.2 and 7.1 mg/l in groups A, B and C; the corresponding trough concentration averaged 2.0, 2.3 and 1.3 mg/l. The frequency of tobramycin trough serum concentration above 2 mg/l was 44% in group A, 45% in group B and 0% in group C. Total body clearance of tobramycin averaged 1.04, 1.13 and 1.28 ml/min/kg; apparent volume of distribution averaged 0.84, 0.81 and 0.61 l/kg; and elimination half-life averaged 9.3, 8.9 and 5.6 h in groups A, B and C. Group M consisted of seven infants with 1.0-1.25 kg birth weight; group N had six infants 1.26-1.50 kg birth weight; group O had seven infants 1.51-2.0 kg birth weight; and group P had six infants 2.1-3.5 kg birth weight. Steady-state peak serum concentration of tobramycin averaged 5.7, 7.3, 7.8 and 7.1 mg/l; and the trough serum concentration averaged 2.2, 2.4, 1.9 and 1.3 mg/l in groups M, N, O and P.(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight↗
PubMed1984

Delivery of tobramycin by three infusion systems.

The delivery of tobramycin was studied at the flow rates of 2, 4 and 6 ml/h after injection into the various sites of IVAC, IMED and Auto Syringe infusion systems. The actual times were markedly longer than the predicted times of delivery, especially for all sites of IVAC system and Buretrol site of IMED system. About 20% of tobramycin was never delivered by the Buretrol sites of IVAC and IMED during a 12-hour period at the flow rate of 2 ml/h. If tobramycin delivery is to be assured within 30 min after the start of infusion, at 2-6 ml/h, proximal y-site of IMED or Auto Syringe systems must be utilized. These data suggest the need for considering the method of tobramycin infusion when monitoring and interpreting its serum concentrations.

Evaluation Studies as Topic↗
PubMed1984

Interaction of physio-medical and psychosocial variables in age-related functional impairments.

Frequency of social interaction was studied in a group of twenty-five veterans who were temporary residents on a VA Nursing Home Care Unit. Serial learning tasks with a 4 sec. and 10 sec. exposure period and simple and choice reaction time tasks were also studied. At the conclusion of testing, attitudes toward aging, life satisfaction, and physical and mental impairment were assessed. "Social Activity" was positively correlated with each of four measures of serial learning, but was uncorrelated with either choice or simple reaction time. "Social Activity" was also correlated with more positive attitudes toward aging and with increased life satisfaction. However, certain aspects of physical and mental impairment were also related to task performance and level of social activity, suggesting that the psychosocial-behavior relationships observed may be partly mediated by a third factor, that is, the health status of the participant.

Aged↗
PubMed1984

The potential value of the sedimentation rate in monitoring treatment outcome in puncture-wound-related Pseudomonas osteomyelitis.

Recently, a recommendation was made to treat Pseudomonas osteomyelitis in children with only ten to 14 days of postsurgical antibiotics. However, there were no clinical or laboratory measurements to monitor the response. Fourteen new cases of puncture-wound-related Pseudomonas osteomyelitis of the foot in children were investigated to examine the response of erythrocyte sedimentation rate (ESR) to treatment. The ESR was increased in 12/12 patients with a mean peak of 41 mm/hr and a mean duration of 30 days. After appropriate treatment was begun, the ESR decreased at a mean rate of 1.1 mm/day. In four of five patients with a poor treatment response, the ESR remained elevated until antibiotics were changed (in 3) or surgery performed (in 1). One patient with an abnormal ESR at completion of three weeks of postoperative antibiotics had a relapse after one year. These data suggest a need for careful assessment of treatment response, such as declining ESR, before antibiotics are discontinued at an arbitrary postoperative time period.

Adolescent↗
PubMed1984

Acetaminophen accumulation in pediatric patients after repeated therapeutic doses.

Acetaminophen serum concentrations were studied in 21 infants and children with fever. The maximum serum concentrations ranged from 9.96 to 19.6 micrograms/ml after a single dose of 12-14 mg/kg and 13.9 to 40.1 micrograms/ml after a single dose of 22-27 mg/kg. Ten patients were restudied at steady-state after repeat doses had been given every 4 or 8 h for 1 to 3 days. Total area under the acetaminophen serum concentration-time curve normalized for dose averaged 0.181 (ml/min/kg)-1 after the first dose and 0.202 (ml/min/kg)-1 at steady-state (p less than 0.05). Five patients showed a 13 to 44% increase in the AUC; one had a 10% decrease in the AUC; and four had less than 6% change in the AUC. There was no evidence of hepatotoxicity. These data suggest that acetaminophen may accumulate after repeated therapeutic doses in children with fever.

Acetaminophen↗
PubMed1983

Regional localization of [14C] methylphenidate in rabbit brain.

1. Neuroanatomical distribution of [14C] methylphenidate has been examined in rabbit brain following intracerebroventricular administration. 2. After about a week of implantation of cannula, in lateral ventricle, in albino rabbits, [14C] methylphenidate was injected through the cannula. The distribution of [14C] methylphenidate was examined at 15, 60 and 180 min after the injection in twelve brain regions. 3. The highest levels were observed at the first sampling time (15 min), in medulla and cervical spinal cord. Pons, caudate, tegmentum and hypothalamus also showed significant uptake of [14C] methylphenidate. Cerebral cortex and thalamus showed very low uptake. 4. The uneven distribution suggests a special affinity of methylphenidate for certain brain regions. The implications of this finding for the central actions of methylphenidate are discussed.

Animals↗