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Biomedical subjects

P Hwang

Publications and source records attributed to P Hwang.

At least 19 recordsLinked to original sources
PubMed2000

Disability evaluation in children with hemidecorticectomy: use of the activity scales for kids and the pediatric evaluation disability inventory.

The purpose of this study is to investigate the level of disability of children who are either candidates for or have undergone a hemidecorticectomy. The Activity Scales for Kids and the Pediatric Evaluation Disability Inventory were demonstrated to be useful measurement tools yielding comparative results between subgroups. Overall, children with congenital disease seemed less autonomous postoperatively than were preoperative patients or children with acquired disease. Age at surgery and the interval between seizure onset and surgery are potentially important predictors of disability. This could reflect the importance of timing of surgery, development, environment, and possibly brain plasticity processes in this population.

Adolescent↗
PubMed1999

Prevalence and impact of upper gastrointestinal symptoms in the Canadian population: findings from the DIGEST study. Domestic/International Gastroenterology Surveillance Study.

OBJECTIVE: The prevalence and impact of upper gastrointestinal (GI) symptoms in the general population are poorly defined. Most data are obtained from selected samples derived from patients presenting to health care providers. As part of a larger international effort (The DIGEST study), we examined the prevalence of upper GI symptoms among the general Canadian population, as well as their psychosocial and economic impact. METHODS: A sample of 1036 adults was studied, its demographic characteristics closely matching those of the general Canadian population. A validated detailed questionnaire measured the prevalence, severity, and frequency of 15 digestive symptoms, as well as demographic information, use of medication and medical resources, other illnesses, and dietary habits. The Psychological General Well-Being Index, a self-administered questionnaire, assessed the individual's subjective sense of well-being. RESULTS: Of the sample population, 28.6% reported substantial symptoms in the preceding 3 months, the majority (111/153 subjects) for >1 yr; 34.1% reported having never experienced significant GI symptoms. The most bothersome symptoms were primarily related to dysmotility-like symptoms in 54.9% of those with chronic symptoms, ulcer-like symptoms in 12.4%, and related to heartburn in 42.5%. Chronic upper GI symptoms were associated with a highly significant (p < 0.001) decrease in all facets of the Psychological General Well Being Index. CONCLUSIONS: Upper GI symptoms are very prevalent in the general Canadian population and substantially affect the quality-of-life and psychological well-being of those affected. Dysmotility-like symptoms, rather than heartburn, are the most common chronic upper gastrointestinal symptoms in the general population.

Adolescent↗
PubMed1999

Evaluation of gross and fine motor functions in children with hemidecortication: predictors of outcomes and timing of surgery.

The purpose of this study is three-fold: First, to determine the levels of gross and fine motor functions in children before and after hemidecortication, using standardized measurement tools; second, to investigate if predictors of these outcomes can be characterized; and third, to explore if both clinical measures and functional magnetic resonance imaging (MRI) potentially can identify optimal timing of surgery. The Gross Motor Function Measure and the Quality of Upper Extremity Skills Test are shown to be comprehensive, standardized outcome measures of movement performance in affected children. Age at surgery and interval between age at seizure onset and age at surgery could be the most reliable predictors of clinical outcomes. Functional MRI studies are valuable in exploring the potential of the cortical reorganization that sustains residual sensorimotor function. The combination of clinical measures with functional MRI is a promising method of inquiry into developmental and plasticity processes.

Adolescent↗
PubMed1998

Histology and histomorphometry of ethmoid bone in chronic rhinosinusitis.

Mucosal changes have been well described in chronic sinusitis, yet little is known about the underlying bone, despite clinical and experimental evidence suggesting that bone may be involved in chronic sinusitis. Techniques of undecalcified bone analysis were used for detailed histologic examination of ethmoid bone in chronic sinusitis compared with controls. Bone synthesis, resorption, and inflammatory cell presence were specifically assessed. Additionally, histomorphometry techniques were used to determine ethmoid bone physiology in individuals undergoing surgery for chronic sinusitis. Overall, individuals undergoing surgery for chronic sinusitis were found to have evidence of marked acceleration in bone physiology with histologic changes including new bone formation, fibrosis, and presence of inflammatory cells. These findings are compared with osteomyelitis in long bone and the jaw. The suggestion that underlying bone may serve as a catalyst for chronic sinusitis is supported and implications for therapy are discussed.

Adult↗
PubMed1998

Surgical treatment of epilepsy in tuberous sclerosis: strategies and results in 18 patients.

BACKGROUND: Seizures in patients with tuberous sclerosis complex (TSC) are often intractable to antiepileptic medications and searching investigation may provide evidence that surgical treatment can be considered. OBJECTIVE: To review the results of investigation and surgical therapy, a treatment modality not generally considered in patients with medically refractory seizures and TSC. METHODS: We report 18 patients (9 male) with TSC who underwent surgical treatment of medically refractory epilepsy. Twelve patients had a well-localized epileptogenic lesion and were treated by lesionectomy or focal resection. Resections were: 7 frontal, 4 temporal, 1 frontotemporal, 1 occipital, and 1 frontoparietal. Four patients underwent more than one operation. Six patients had corpus callosotomy (CC). RESULTS: Follow-up ranged from 1 month to 47 years. Outcome of the patients treated by resection was excellent in 7 (5 were seizure-free and 2 had auras only), good in 1, fair in 3, and 1 was lost to follow-up. Best outcome was obtained in patients who had focal seizures and good imaging and EEG correlation, although they might have multiple seizure types, other imaging abnormalities, and multifocal or generalized EEG findings. When there was no such correlation, CC was found to be an option as five patients had at least some improvement and only one showed no change. CONCLUSION: Surgical treatment of patients with TSC and intractable epilepsy is most effective when a single tuber or epileptogenic area can be identified as the source of seizures and resected. This may be possible even when other tubers or diffuse EEG abnormalities are present. In patients with unlocalizable epileptic abnormalities, palliation may be obtained by CC.

Adolescent↗
PubMed1997

Coexistence of hemimegalencephaly and chronic encephalitis. Detection of cytomegalovirus by the polymerase chain reaction.

We report the extraordinary association of hemimegalencephaly with chronic encephalitis and cytomegalovirus (CMV) positivity in a 5-month-old infant with intractable seizures and a left hemisphere resection. Microscopy revealed a severe neuronal migration disorder (NMD) with fusion of gyri, marked disarray of neuronal lamination, neuronal gigantism and extensive neuronal heterotopias. Also widespread were microglial nodules, gliosis and nodular calcifications and some foci of frank necrosis with calcification. Occasional perivascular and leptomentingeal lymphocytic infiltrates were present. No viral inclusions were identifiable. Polymerase chain reaction on multiple specimens showed unequivocal CMV positivity. In intrauterine CMV infection. NMDs such as polymicrogyria are well recognized, but the association of hemimegalencephaly with CMV infection has not previously been described. Our finding of chronic encephalitis with CMV positivity and hemimegalencephaly in the same patient raises questions about the role of CMV in the etiopathogenesis of the NMD.

Brain↗
PubMed1997

Intracranial and spinal metastases from a ganglioglioma with unusual cytogenetic abnormalities in a patient with complex partial seizures.

We describe an unusual clinical presentation of a ganglioglioma in a patient with complex partial seizures. The patient underwent a right temporal lobectomy with subtotal tumor resection at age 15 years, followed by a complete resection 1 year later. Follow-up MRI scan a year later documented recurrence and leptomeningeal dissemination. Another biopsy was performed. Pathological examination revealed similar histology in all three resections, with a ganglioglioma showing no evidence of anaplasia. The tumor exhibited a number of karyotypic abnormalities, notably, a paracentric inversion of chromosome 7. In summary, despite lacking anaplastic features by conventional histological criteria, this ganglioglioma showed an unsusual karyotype and demonstrated radiological evidence of widespread dissemination.

Adolescent↗
PubMed1997

Efficacy of pentosan polysulfate in the treatment of interstitial cystitis: a meta-analysis.

OBJECTIVES: To determine the efficacy of pentosan polysulfate (Elmiron) compared to placebo in the treatment of interstitial cystitis. METHODS: The data sources used were MEDLINE, Excerpta Medica, and International Pharmaceutical Abstracts databases, and the manufacturer. Bibliographies of articles obtained were reviewed. The keywords used were pentosanpolysulfate, pentosanpolysulfate sodium, and pentosan. Inclusion criteria were blinded selection of English language, prospective, randomized, placebo-controlled comparative trials; > or = 8 weeks' duration; > or = 300 mg daily; adult humans with > or = 1 symptoms including pain, urgency, frequency, and nocturia; symptoms for > or = 12 months; normal urinalysis; negative findings for urine culture and cytology. Exclusion criteria were hemorrhagic cystitis; drug-, microbial-, or radiation-induced cystitis; carcinoma in situ; other influencing diseases. The outcome of success was defined as a > or = 50% decrease in pain, urgency, frequency, and nocturia. The number of successes was extracted by blinded investigators, treating withdrawals as failures. The percentage difference in success rates of pentosan polysulfate and placebo, and the number needed to treat (NNT) were determined for each variable; P values and 95% confidence intervals (CIs) were determined for combined data. Homogeneity of effect was determined by calculating Q (chi-squared). Article quality was assessed using the Chalmers scale to determine if quality affected outcome. Effective inter-rater reliability was determined using Rosenthal's method. Significance was set at P < 0.05. RESULTS: Four studies were included. Data were extracted from all four studies for pain (n = 398), three for urgency (n = 306), two for frequency (n = 160), and one study for nocturia (n = 106). The differences (95% confidence limits) were pain: 16.6% (95% CI 8%, 25%), NNT = 7; urgency: 13.0% (1.0%, 25%), NNT = 7.5; frequency: 16.7% (2.3%, 31.1%), NNT = 6; nocturia: -1% (-19.8%, 21.8%). P values from homogeneity tests were not significant. Mean quality scores were 63.8%, 48.1%, 50.4%, and 65.6%, respectively, in the four studies; the effective inter-rater reliability was 0.96. Results did not differ when weighted by quality score. CONCLUSIONS: Pentosan polysulfate is more efficacious than placebo in the treatment of pain, urgency, and frequency associated with interstitial cystitis. Pentosan polysulfate is not significantly different from placebo in treating nocturia associated with interstitial cystitis.

Adult↗
PubMed1997

Is saliva suitable for therapeutic monitoring of anticonvulsants in children: an evaluation in the routine clinical setting.

Studies performed in the research setting suggested that saliva instead of blood may be used for therapeutic drug monitoring (TDM) of anticonvulsants in children. This is an attractive alternative because its collection is painless, and simpler and cheaper than blood drawing. Citric acid stimulation of saliva secretion facilitates sampling in the youngest patients. The aim of the study was to evaluate the suitability of saliva in routine TDM of anticonvulsants in infants and children with epilepsy. Blood and saliva samples were obtained simultaneously during routine TDM in 170 patients on chronic anticonvulsant drug therapy attending a neurology clinic. Saliva, plasma total, and plasma free concentrations of anticonvulsants were measured by high-performance liquid chromatography and enzyme multiplied immunoassay technique. Strong and highly significant correlations between saliva and plasma concentrations were found over a wide range of concentrations for carbamazepine, phenytoin, clobazam, and desmethylclobazam, and for phenobarbital in children > or = 8 years of age (r = 0.90 to 0.97; p < 0.001). Correlations between saliva and plasma concentrations were poor for phenobarbital in children < 8 years of age and for valproate. Correlations between saliva and plasma-free anticonvulsant concentrations were equal or only slightly better than between saliva and plasma total concentrations. Citric acid-stimulated saliva constitutes a convenient alternative for TDM of carbamazepine and phenytoin therapy in pediatric patients and of phenobarbital in children > or = 8 years of age.

Adolescent↗
PubMed1997

Combined utility of functional MRI, cortical mapping, and frameless stereotaxy in the resection of lesions in eloquent areas of brain in children.

We studied 16 children with lesions in the eloquent brain to determine if the amalgamation of information from functional magnetic resonance imaging (fMRI), frameless stereotaxy, and direct cortical mapping and recording could facilitate the excision of these lesions while minimizing potential neurological deficits. The mean age of the children was 10 years. Fourteen children presented with seizures. All lesions were located in or near eloquent cerebral cortex. fMRI was successful in all patients in delineating the relationship between the lesion and regions of task-activated cortex. The ISG wand was utilized in all cases for scalp and bone flap placement, and for intraoperative localization of the lesion. Direct cortical stimulation or recording of phase reversals with somatosensory evoked potentials helped delineate the central sulcus and language cortex in patients with lesions near the motor or language cortex. Intraoperative electrocorticography (ECoG) was utilized in all patients who presented with seizures to guide the extent of resection of the epileptiform cortex. Ten children had benign cerebral neoplasms, nine of which were totally resected. The other diagnoses included vascular malformations, Sturge-Weber, tuberous sclerosis, Rasmussen's encephalitis, and primitive neuroectodermal tumor. Only 1 patient with a left Rolandic AVM developed a new neurological deficit postoperatively. Thirteen of fourteen patients who presented with seizure disorders were rendered either seizure free or improved in terms of seizure control postoperatively. Follow-up has ranged from 12 to 18 months, with a mean follow-up of 15 months. We conclude that the techniques of fMRI, frameless stereotaxy, direct cortical stimulation and recording can be utilized in sequence to accurately localize intracerebral lesions in eloquent brain, and to reduce the morbidity of resecting these lesions in children.

Adolescent↗
PubMed1997

Interactions of clobazam with conventional antiepileptics in children.

Clobazam is a 1,5-benzodiazepine effective in antiepileptic therapy of children and adults. Presently it is mainly used as adjuvant therapy for intractable seizures. Our objective was to evaluate the effect of clobazam on the apparent clearance of other antiepileptic drugs at steady state, and to determine the factors that determine the plasma levels of clobazam and its active metabolite N-desmethylclobazam. Patients were 74 children with intractable seizures who received treatment with clobazam at our institution as part of the Canadian Cooperative Clobazam Study Group during the years 1987 to 1991. Serum concentrations of clobazam, N-desmethylclobazam, and of concomitant antiepileptic drugs were monitored and prospectively collected. The effect of clobazam treatment on the apparent clearance steady state of the other antiepileptic drugs was determined by statistical comparison of the clearances of each drug before and after initiation of clobazam treatment using Wilcoxon's signed rank test. The effects of dosage, age, and concomitant antiepileptic therapy on the levels of clobazam and N-desmethylclobazam was assessed by multivariate analysis. Response to treatment and incidence of adverse effects were evaluated for each conventional antiepileptic drug to possibly identify favorable or unfavorable combinations with clobazam. Whereas the clearances of most conventional antiepileptics are not affected by cotherapy with clobazam, the apparent clearances of valproic acid and primidone are significantly reduced in the presence of clobazam. Serum concentrations of clobazam increased with dosage and age, and decreased with phenobarbital cotherapy. Serum concentrations of N-desmethylclobazam significantly correlated with clobazam serum levels, age, or clobazam dosage and were significantly increased by cotherapy with phenytoin or carbamazepine. None of the concomitantly used drugs were associated with increased or decreased rate of seizure control. Twelve patients experienced mild adverse drug effects that were not associated with particular cotherapy, clobazam dose, or plasma concentrations. When clobazam is added to a therapy regimen that includes valproic acid, the patient should be closely followed for possible adverse drug reactions caused by elevated valproic acid serum concentrations, and monitoring of valproate serum levels should be considered. When clobazam doses are gradually increased to achieve an optimal clinical effect, the interactions with phenobarbital, carbamazepine, and phenytoin do not necessitate therapeutic drug monitoring of clobazam or N-desmethylclobazam, because there is a large therapeutic window and a poor correlation between plasma concentrations and therapeutic efficacy.

Adolescent↗
PubMed1996

Localization of focal cortical lesions influences age of onset of infantile spasms.

PURPOSE: To determine whether the localization of focal cerebral lesions affects age of onset of infantile spasms (IS). METHODS: We reviewed 216 cases of IS and identified patients with focal cerebral lesions confined to frontal, centrotemporoparietal, or occipital regions. The age of onset of spasms in each of the three groups was analyzed. RESULTS: Ninety-three patients were found to have focal cerebral lesions confined to one of the three regions previously described. The mean age of onset of IS was 3.36 +/- 1.71 months in patients with occipital lesions, 6.26 +/- 2.68 months in centrotemporoparietal lesions, and 9.83 +/- 2.56 in frontal lesions. CONCLUSIONS: Occipital lesions are found to be associated with earliest onset of spasms, whereas frontal lesions are rare and associated with latest spasms onset. The age distribution pattern of spasms onset according to localization of cortical lesion is in close correlation with that of normal sequence of brain maturation. This supports the hypothesis that cerebral lesions located in critical areas of brain maturation have a role in the genesis of infantile spasms.

Age of Onset↗
PubMed1995

Chronic encephalitis and epilepsy (Rasmussen's encephalitis): detection of cytomegalovirus and herpes simplex virus 1 by the polymerase chain reaction and in situ hybridization.

We made a pathologic diagnosis of chronic encephalitis on surgical resections or autopsy material in 10 patients with intractable seizures and studied the specimens by immunohistochemistry for herpes simplex virus (HSV) 1 and 2 and cytomegalovirus (CMV) as well as by the polymerase chain reaction (PCR) for viral DNA sequences (HSV1, HSV2, and CMV). We also assessed eight patients (nonepileptic) with pathologically documented or clinically suspected encephalitis and five resections from epileptics without encephalitis. Immunohistochemistry for viral antigens was negative in all cases. Using PCR assay, CMV was present in six and HSV1 in two of 10 epilepsy patients with chronic encephalitis. We demonstrated CMV by in situ hybridization in two of the six patients positive for CMV by PCR. We found no viral sequences by PCR in five epileptics without encephalitis. Of the eight patients (nonepileptic) with clinically suspected or pathologically confirmed encephalitis, two cases showed CMV sequences by PCR. These observations suggest that PCR allows detection of viral sequences in some cases of chronic encephalitis associated with epilepsy that may be missed by in situ hybridization.

Adolescent↗
PubMed1995

Pediatric magnetic source imaging.

Magnetic source imaging has changed the perspective of managing pediatric patients with epilepsy since its introduction into clinical imaging in the pediatric population. Magnetic source imaging can be important in understanding pediatric functional neuroanatomy and for epileptic surgery in children with intractable seizures. The use and efficacy of magnetic source imaging for surgical planning and patient management is demonstrated by case reports presented in this article.

Brain Mapping↗
PubMed1994

Saliva versus blood sampling for therapeutic drug monitoring in children: patient and parental preferences and an economic analysis.

The objective of this study was to conduct an assessment of patient and parental preferences and an economic analysis of hospital costs in sampling blood and saliva for therapeutic drug monitoring (TDM). Costs and preferences were evaluated in the course of a study, which compared anticonvulsant concentrations in blood routinely drawn for therapeutic monitoring and in saliva in infants and children attending a pediatric neurology clinic. Parents of 84.8% of children, and half of the children, indicated a preference for saliva sampling over venous blood drawing. Children who had been on medications that required therapeutic monitoring for < 2 years were more likely to prefer saliva sampling as compared to those who were under treatment for > or = 2 years. Computation, based upon a basic assumption that a registered nurse obtained blood and a medical technician or a registered nurse assistant sampled saliva, indicated that for every 1,000 cases of changing from blood to saliva sampling, total cost savings would amount to $1,930 for cooperative children and $1,660 for infants and uncooperative children. This saving is equivalent to approximately 100 h of a registered nurse's initial salary. The important contributions to the differential cost were derived from the requirements for more highly trained individuals to take the blood sample and from the doubling time required for the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Medical treatment of Rasmussen's syndrome (chronic encephalitis and epilepsy): effect of high-dose steroids or immunoglobulins in 19 patients.

We treated 19 patients with Rasmussen's syndrome (chronic encephalitis and epilepsy)--a rare progressive disorder of unknown etiology causing focal epilepsy, hemiparesis, and intellectual deterioration--with intravenous immunoglobulins, high-dose steroids, or both, to control seizures and improve the end point of the disease. Ten of 17 patients receiving steroids, and eight of nine patients receiving immunoglobulins, had some reduction of seizure frequency in the short term. Improvement in hemiparesis was slight. The effect of these drugs in ameliorating the end point of the disease in the long term remains unknown, and further multicenter studies with standardized protocols are warranted.

Adolescent↗