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Biomedical subjects

R C Woody

Publications and source records attributed to R C Woody.

At least 19 recordsLinked to original sources
PubMed1994

Valproate increases glutaminase and decreases glutamine synthetase activities in primary cultures of rat brain astrocytes.

It has been proposed that hyperammonemia may be associated with valproate therapy. As astrocytes are the primary site of ammonia detoxification in brain, the effects of valproate on glutamate and glutamine metabolism in astrocytes were studied. It is well established that, because of compartmentation of glutamine synthetase, astrocytes are the site of synthesis of glutamine from glutamate and ammonia. The reverse reaction is catalyzed by the ubiquitous enzyme glutaminase, which is present in both neurons and astrocytes. In astrocytes exposed to 1.2 mM valproate, glutaminase activity increased 80% by day 2 and remained elevated at day 4; glutamine synthetase activity was decreased 30%. Direct addition of valproate to assay tubes with enzyme extracts from untreated astrocytes had significant effects only at concentrations of 10 and 20 mM. When astrocytes were exposed for 4 days to 0.3, 0.6, or 1.2 mM valproate and subsequently incubated with L-[U-14C]glutamate, label incorporation into [14C]glutamine was decreased by 11, 25, and 48%, respectively, and is consistent with a reduction in glutamine synthetase activity. Label incorporation from L-[U-14C]glutamate into [14C]aspartate also decreased with increasing concentrations of valproate. Following a 4-day exposure to 0.6 mM valproate, the glutamine levels increased 40% and the glutamate levels 100%. These effects were not directly proportional to valproate concentration, because exposure to 1.2 mM valproate resulted in a 15% decrease in glutamine levels and a 25% increase in glutamate levels compared with control cultures. Intracellular aspartate was inversely proportional to all concentrations of extracellular valproate, decreasing 60% with exposure to 1.2 mM valproate.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1994

Glial cytokines as neuropathogenic factors in HIV infection: pathogenic similarities to Alzheimer's disease.

The mechanisms by which human immunodeficiency virus (HIV) infection provokes progressive neurodegeneration and dementia in acquired immunodeficiency syndrome (AIDS) remain obscure. In HIV-infected (HIV+) individuals, we found that the brain cells preferentially infected by HIV, viz. the microglia, were abundant, activated, and intensely immunopositive for interleukin-1 alpha (IL-1 alpha), an immune response-generated cytokine that increases the synthesis and processing of beta-amyloid precursor proteins (beta-APP) and promotes proliferation and activation of astroglia. We also found an increase in the number of activated astroglia expressing elevated levels of S100 beta, a cytokine that increases intraneuronal calcium levels and promotes excessive growth of neuronal processes (neurites). These glial changes were accompanied by increased expression of beta-APP immunoreaction product in neurons and overgrown (dystrophic) neurites. In addition, some neurons contained monoclonal antibody Tau-2 immunopositive, neurofibrillary tangle-like structures. Our findings provide evidence that glial activation with increased expression of IL-1 alpha and S100 beta may be important in the neuropathogenesis of AIDS dementia. We propose that HIV infection promotes excessive microglial IL-1 alpha expression with consequent astrogliosis and increased expression of S100 beta. Overexpression of these two cytokines may then be involved in AIDS neuropathogenesis by inducing gliosis, growth of dystrophic neurites, and calcium-mediated neuronal cell loss in AIDS.

Adult↗
PubMed1991

Enhanced neutrophil function in children on bromide therapy.

The final step in neutrophil bacterial killing is formation of a toxic halide complex. For this reason, we studied neutrophil function in children receiving bromide anticonvulsant therapy. Whole blood and serum were obtained from 7 patients with seizure disorders treated orally with triple bromide elixir to examine neutrophil function as measured by luminol enhanced chemiluminescence (CL). Serum bromide concentrations [Br-] were determined concomitantly. There was a direct correlation between [Br-] and CL activity of neutrophils (r = 0.87) with peak CL responses significantly higher than controls when [Br-] were in the therapeutic range (10-20 mM). With [Br-] above 25 mM, CL activity was reduced. Serum from patients also enhanced CL of control neutrophils with a similar relationship to measured [Br-]. To confirm that enhanced neutrophil activity was attributable to [Br-] use, [Br-] ranging from 0-50 mM were added to control neutrophils in otherwise normal physiologic conditions and the CL assay was performed. Results expressed as percent of control values were as follows: [Br-] 5 mM, 110%; 10 mM, 158%; 15 mM, 194%; 20 mM, 252%; 25 mM, 136%; 30 mM, 364%; and 50 mM, 205%. These data demonstrate that Br- enhances phagocytic and bactericidal activity of neutrophils and suggest that Br- therapy may augment host defense capabilities.

Blood Bactericidal Activity↗
PubMed1991

Absence of beta-amyloid immunoreactivity in mesial temporal lobe in Cockayne's syndrome.

Cockayne's syndrome is associated with dementia and other physical signs of premature senescence. Death usually occurs in the first or second decade of life. Because previous neuropathologic descriptions have included neurofibrillary tangles and calcific and dystrophic cerebrovascular changes, we examined the mesial temporal lobes of three children with Cockayne's syndrome (confirmed by 254-nm ultraviolet light studies). Immunohistochemistry was used to determine if beta-amyloid immunoreactivity was present in the parenchyma or cerebral blood vessels. Tissues from the mesial temporal lobe of patients with Alzheimer's disease and Down syndrome were used as controls. None of the three temporal lobes from patients with Cockayne's syndrome contained beta-amyloid immunoreactive material in either the parenchyma or vessels; all of the Alzheimer's disease and Down syndrome controls had beta-amyloid immunoreactivity.

Alzheimer Disease↗
PubMed1990

Phenytoin protein binding in pediatric patients with acute traumatic injury.

Phenytoin (DPH) is commonly used to treat seizures associated with acute head injury. Consequent to decreases in DPH protein binding in such patients, the DPH free fraction (DPHff) may increase and thereby produce symptoms compatible with DPH toxicity despite the presence of total serum concentrations within the usually accepted therapeutic range. We examined the effect of acute traumatic injury on DPH protein binding in 13 hospitalized pediatric patients. In addition to total and free DPH serum concentrations, biochemical variables including blood pH, total and direct bilirubin, serum urea nitrogen, creatinine, albumin, gamma glutamyltransferase (GGT), and free fatty acid concentrations were measured serially over 10 days. The DPHff was compared between selected time intervals in hospitalized patients and data obtained in a control population of 27 epileptic outpatients who were maintained on DPH. Additionally, a multiple regression model was used to examine for covariance between the DPHff and the respective biochemical variables in the hospitalized patients. In the study patients, the DPHff progressively increased, attaining a maximum value (8.5 +/- 0.7%) on the fifth hospital day which was significantly greater (6.4 +/- 0.7%, p less than .05) than that on day 1 and also in the control group (6.1 +/- 0.3%; p less than .01). Blood pH, serum albumin, free fatty acids, creatinine and bilirubin concentrations did not change, but GGT did increase significantly over the 10-day sampling period. A significant (r = .51, p less than .0001) linear relationship was found between the DPHff and the serum albumin concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1990

The use of serum electrolyte concentrations determined by automated analyzers to indirectly quantitate serum bromide concentration.

Bromide is not often prescribed today as antiepileptic therapy. One reason is that serum bromide concentrations are not routinely performed in hospital laboratories, making clinical decisions difficult. Because of bromide ion interference with the electrodes of commonly used automated electrolyte analyzers, factitious "hyperchloremia" (and in some cases, "hyperbicarbonatemia"), are produced. These values, and the resulting calculated anion gap, correlate well with the measured serum bromide concentration. The correlation permits results from routine automated electrolyte analyzers to be used to indirectly determine serum bromide concentration.

Acid-Base Equilibrium↗
PubMed1990

Adverse effects of trimethoprim-sulfamethoxazole in a child with dihydropteridine reductase deficiency.

A child with dihydropteridine reductase (DHPR) deficiency developed signs of dopamine insufficiency after being given trimethoprim-sulfamethoxazole (TMP-SMX). She recovered function after the antibiotic was stopped, which suggests that it adversely influenced dopamine metabolism in the CNS. The authors speculate that TMP, a dihydrofolate reductase inhibitor, was the major cause of the patient's deterioration, and suggest that it and other dihydrofolate inhibitors, notably methotrexate, are contra-indicated for patients with DHPR deficiency.

Child, Preschool↗
PubMed1990

Migraine headache in the infant and young child.

Migraine is a common clinical diagnosis, occurring in 4-10% of school age children. Migraine in the infant and preschool child has been infrequently described in retrospective studies. We report the prospective evaluation and therapy of six children (5-42 months) with migraine. In four of the children, Prensky's criteria were used for diagnosis, while the two youngest children presented with ophthalmoplegic migraine. All children had a strong family history of migraine and presented with headache and prominent features including facial pallor, irritability, sleep disturbance or mood changes. The oldest four children were successfully treated with either amitriptyline or imipramine in low doses. The infants with ophthalmoplegic migraine failed to completely respond to any therapy. At followup 2 to 18 months later, all children were well and without toxicity. The pediatrician should be aware that migraine may begin in infancy and can be effectively and safely treated.

Amitriptyline↗
PubMed1990

Bromide therapy for pediatric seizure disorder intractable to other antiepileptic drugs.

Triple bromide elixir was used as an adjunctive antiepileptic drug in 11 children whose seizure disorders were intractable to other antiepileptic therapy. The patients' ages ranged from 2 to 17 years. The seizure disorders treated included photosensitive epilepsy (one case), acquired epileptic aphasia (one case), Lennox-Gastaut syndrome (three cases), and symptomatic localization-related epilepsies (six cases). Two patients' seizures completely stopped with bromide therapy. Four patients had a significant and sustained improvement on bromide therapy, while three more had a transient improvement. In these six patients with complete or significant control, the mean therapeutic dose was 33 mg bromide/kg daily, and the mean therapeutic serum concentration was 14.1 mmol/L (range, 4 to 30.5 mmol/L). The combination of bromide with valproate appeared to be particularly effective in these patients. Toxicity was minimal, and in only one patient was the medication stopped, because of anorexia and weight loss. Given the low cost, long half-life, and minimal toxicity when serum bromide concentrations are followed, bromide therapy should be considered as adjunctive antiepileptic drug therapy for patients whose seizures are intractable to other drugs.

Adolescent↗
PubMed1990

Telencephalic dysgenesis associated with presumptive maternal carbon monoxide intoxication in the first trimester of pregnancy.

We report the association of telencephalic dysgeneses (expected to occur around week 6 of gestation) with presumptive maternal carbon monoxide intoxication. This case supports the hypothesis that carbon monoxide intoxication at critical periods of human brain development may lead not only to decreased brain size and hypoxic-ischemic lesions, but also to dysgeneses.

Abnormalities, Drug-Induced↗
PubMed1989

Rectal anticonvulsants in seizure patients undergoing gastrointestinal surgery.

Gastrointestinal (GI) surgery in children with seizure disorders is often complicated by difficulties in administering oral anticonvulsant medications in the preoperative and postoperative periods. Because many newer anticonvulsants do not have parenteral formulations, intravenous phenobarbital, phenytoin, and benzodiazepines may appear necessary in the perioperative period. Eight children with neurologic disease with severe seizure disorders underwent gastrostomy placement and Nissen fundoplication. Perioperatively, their anticonvulsants were given successfully via the rectum. Rectal administration of anticonvulsants is a useful alternative route for drug therapy in seizure patients who are undergoing GI surgery.

Administration, Rectal↗
PubMed1989

Histocompatibility determinants in childhood postinfectious encephalomyelitis.

Postinfectious encephalomyelitis and multiple sclerosis have clinical, immunologic, and neuroradiographic similarities. We studied HLA determinants in six white children consecutively diagnosed with postinfectious encephalomyelitis. Each of the children had HLA determinants which have been associated with multiple sclerosis. Relative risk (RR) calculations demonstrated that these antigens and genotypes occurred significantly more often in patients with postinfectious encephalomyelitis than in the control population (A3, RR 6.14; B7, RR 6.14; DR2, RR 4.51; A3B7, RR 9.36; A3DR2, RR 5.83; B7DR2, RR 6.13; A3B7DR2, RR 10.90). These data suggest that children with postinfectious encephalomyelitis are genetically predisposed to this demyelinating disease. Although the same HLA determinants were found in these patients as in those with multiple sclerosis, studies of a larger number of postinfectious encephalomyelitis patients will be needed before it can be concluded that the two diseases share a common genetic propensity.

Child↗
PubMed1989

Progressive intracranial calcification in dihydropteridine reductase deficiency prior to folinic acid therapy.

Hyperphenylalaninemia in infants and children may be caused by a deficiency of dihydropteridine reductase (DHPR). Recommended therapy includes folinic acid as a source of tetrahydrofolate, a phenylalanine-restricted diet, and both dopamine and serotonin precursors. We report a child with progressive basal ganglia and other subcortical calcifications prior to the use of folinic acid. Six other reported cases of DHPR deficiency demonstrated similar calcifications prior to folinic acid therapy. Since this pattern of calcification also resembles that seen in CNS folate deficiency caused by both congenital folate deficiency and that which is methotrexate-induced, we propose that intracranial calcification in DHPR deficiency is caused by inadequate CNS tetrahydrofolate and may be prevented by the use of folinic acid. Our patient achieved excellent seizure control following the use of folinic acid, suggesting either a direct or indirect anticonvulsant effect of this compound in patients with DHPR deficiency.

Brain↗