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Biomedical subjects

C W Chow

Publications and source records attributed to C W Chow.

At least 109 records · Page 6Linked to original sources
PubMed1993

Hippocampal sclerosis in children with intractable temporal lobe epilepsy: detection with MR imaging.

OBJECTIVE: Hippocampal sclerosis is the most common lesion associated with temporal lobe epilepsy. Temporal lobectomy is effective for the control of medically refractory seizures in these patients. Before the advent of MR imaging, hippocampal sclerosis was rarely diagnosed preoperatively. The purpose of this study was to determine the frequency of hippocampal sclerosis in children with intractable temporal lobe epilepsy and the accuracy and reliability with which hippocampal sclerosis can be diagnosed on the basis of MR findings in children. MATERIALS AND METHODS: We reviewed the MR images of 53 children (mean age, 10 years) with medically refractory temporal lobe epilepsy. The MR images were reviewed blindly and independently by two radiologists on two occasions, and were classified as showing hippocampal sclerosis, other lesions, or no abnormality. Hippocampal sclerosis was diagnosed when evidence of hippocampal atrophy was present or hippocampal signal intensity was abnormal without evidence of a mass lesion. RESULTS: MR images showed hippocampal sclerosis in 30 children (57%), other lesions in 10 (19%) (tumors in eight, cavernous angioma in one, and ectopic gray matter in one), and no abnormality in 13 (24%) (intraobserver agreement: kappa = 0.77 and 0.84, interobserver agreement: kappa = 0.76). MR lateralization was concordant with ictal EEG in 36 (92%) of 39 children. Hippocampal sclerosis was bilateral in one child and associated with extrahippocampal lesions in nine. Hippocampal sclerosis was detected on MR images of 11 (85%) of 13 children with pathologic confirmation of hippocampal sclerosis. Beneficial results were seen in 26 (90%) of 29 children who had temporal lobectomy. CONCLUSION: Hippocampal sclerosis is the most common lesion in children with intractable temporal lobe epilepsy, and it can be detected reliably and accurately on MR images. We suspect that hippocampal sclerosis is underdiagnosed in children, possibly leading to postponement of surgery in children with refractory seizures.

Adolescent↗
PubMed1992

Impairment of left ventricular diastolic function in systemic lupus erythematosus.

Left ventricular (LV) diastolic performance was evaluated with pulsed-wave Doppler echocardiography in a cross-sectional population of patients with systemic lupus erythematosus (SLE) in search of subclinical myocardial involvement. Such involvement is reported to occur infrequently, despite pathohistologic evidence of myocarditis in up to 70% of patients with SLE. Thirty-five consecutive patients with SLE were evaluated, 14 with active and 21 with inactive disease, and were compared with 30 age-matched healthy control subjects. Twenty-six patients were restudied at 7 months. All had normal LV systolic function, normal pericardial and valvular structures, and no significant valvular regurgitation on Doppler echocardiography. In SLE patients with active disease, indexes of LV diastolic function differed significantly from the inactive group and from control subjects, with marked prolongation of isovolumic relaxation time (104 +/- 18 vs 74 +/- 13 ms, p = 0.0001), as well as reduced peak early diastolic filling velocity (E) (0.69 +/- 0.19 vs 0.83 +/- 0.17 ms, p = 0.01), reduced ratio of early to late diastolic flow velocity (E/A) (1.15 +/- 0.53 vs 1.47 +/- 0.35, p = 0.02), and prolonged mitral pressure halftime (74 +/- 14 vs 65 +/- 8 ms p = 0.01). Similar significant differences were found between the active and inactive SLE patient groups. SLE patients with inactive disease differed from control subjects in only mild prolongation of mitral pressure halftime. Abnormal prolongation of isovolumic relaxation (greater than 100 ms) was found to be the most useful marker of diastolic impairment, being present in 64% of SLE patients with active disease and in 14% of patients with inactive disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Autopsy findings in two siblings with infantile Refsum disease.

Recognition of adrenal atrophy during a review of autopsy findings in two sisters who died at 8 months and 3 1/2 years prompted estimation of very long chain fatty acids, phytanic acid and pristanic acid on wet liver fixed in formalin for 12 years. These were shown to be markedly increased and defects in multiple peroxisomal functions and decrease in particulate catalase were shown in cultured fibroblasts, confirming an abnormality of peroxisomal biogenesis. The patients had presented with failure to thrive, recurrent diarrhoea and vomiting, poor mental development, retinal pigmentation, blindness and in the older patient deafness, with only mild dysmorphic features. Autopsy in the older patient showed adrenal atrophy, cirrhosis, and foamy histiocytes in multiple organs. The brain showed no demyelination, little cytoarchitectural abnormality, occasional perivascular histiocytes in the grey matter and meninges and prominent Purkinje cells in the molecular layer of the cerebellum. In the younger patient the changes were very subtle in spite of the marked clinical similarity. Despite the young age at death the clinicopathological features are most suggestive of infantile Refsum disease. In many situations anatomical pathology can be very useful in the recognition and study of peroxisomal disorders.

Adrenal Glands↗
PubMed1992

Ultrastructure and immunocytochemistry of hepatic peroxisomes in rhizomelic chondrodysplasia punctata.

Peroxisomes were studied in the liver of two rhizomelic chondrodysplasia punctata patients using electron microscopy and catalase cytochemistry. Immunoelectron microscopy was carried out on the liver of one of these patients using antibodies to catalase, acyl-CoA oxidase, bifunctional protein, 3-ketoacyl-CoA thiolase and a 68 kDa peroxisomal membrane protein, in conjunction with protein-A colloidal gold. Moderately to markedly enlarged, flocculent peroxisomes were found in both patients. In one patient they were very heterogeneous with regard to the number per hepatocyte. The peroxisomes had very low levels of catalase as indicated by cytochemistry and immunocytochemistry. The three beta-oxidation enzymes were localised normally within the peroxisomes. The 68 kDa membrane protein was localised to the peroxisomal membranes. Some extra membrane loops were also identified using this antibody.

3,3'-Diaminobenzidine↗
PubMed1992

Chromosomal localization of amplified N-myc in neuroblastoma cells using a biotinylated probe.

G-banded chromosome analysis of neuroblastoma cells from two children revealed homogeneously staining regions (hsr) in one patient and double minutes (dmin) in the other. Subsequently, both abnormalities were confirmed as areas of N-myc amplification using chromosomal in situ hybridization with a biotinylated N-myc probe. In addition, the first patient's karyotype contained a possible derivative chromosome 17, which was also demonstrated to contain amplified N-myc, indicating the presence of an hsr unidentified by G-banding. Intercellular heterogeneity in the degree of amplification was also identified in the nuclei of interphase cells. This technique provides a quick method for detecting gene amplification, the identification of which may have useful clinical implications.

Abdominal Neoplasms↗
PubMed1992

Overexpression of multiple oncogenes related to histological grade of astrocytic glioma.

The expression of the c-erbB-1, c-myc, Ha/N-ras and c-fos oncogenes was investigated in 62 astrocytomas of low, intermediate and high grades by immunogold silver histochemistry. Elevated expression of c-erbB-1 was observed in 95%, 48% and 86% of low, intermediate and high grade tumours respectively, c-myc in 5%, 33% and 76% respectively, Ha/N-ras in 0, 43% and 71% respectively and c-fos in 55%, 48% and 52% respectively. Controls included normal brain and tumour sections immunoreacted with pre-immune serum or with antisera absorbed with synthetic peptides. Analysis of co-overexpression revealed that low grade tumours co-overexpressed a maximum of two of these genes, intermediate grade tumours a maximum of three of these genes, while co-overexpression of all four genes was observed in some high grade tumours. Co-overexpression of c-erbB-1 and c-fos was frequently observed in low grade astrocytomas and may be predictive of non-progression. On the other hand, there was a statistically significant increase in the number of tumours overexpressing Ha/N-ras or c-myc with increasing grade of tumour, suggesting that overexpression of these two oncogenes may be indicative of progression.

Astrocytoma↗
PubMed1992

Minute Y chromosome derived marker in a child with gonadoblastoma: cytogenetic and DNA studies.

A 12 year old girl referred for chromosome analysis because of short stature was found to have karyotype mos 45,X/46,X,+mar. The marker chromosome was observed in 58% of her blood lymphocytes. It was a small, pale staining, spherical fragment with GTL banding and showed faint differentiation along its length with CBG banding. DNA analysis using Y specific probes showed the absence of the testicular determining region and the presence of some short arm and centromeric Y chromosomal material. In situ hybridisation confirmed that the Y chromosomal material was associated with the marker chromosome. At laparotomy the patient was found to have streak gonads. Gonadectomy was subsequently performed and histological examination showed dysgenetic gonads with a dysgerminoma arising from a gonadoblastoma in the left gonad. This case shows that even very small Y derived marker chromosomes with pericentric material can predispose the phenotypic female to gonadal neoplasia.

Base Sequence↗
PubMed1991

Endomyocardial biopsy in infants and children with cardiomyopathy.

We reviewed our experience of endomyocardial biopsy performed on 21 symptomatic infants and children with cardiomyopathy. Clinical congestive cardiomyopathy was noted in 18 patients, 2 had hypertrophic cardiomyopathy, and 1 a restrictive cardiomyopathy. The biopsy findings led to a diagnosis of hemochromatosis in one patient, Adriamycin cardiomyopathy in another, and lymphocytic myocarditis in a third. Five patients had features of endocardial fibroelastosis, one endomyocardial fibrosis, and a further one, a mitochrondrial abnormality. In 11 patients normal or nonspecific features were seen. There were 2 myocardial perforations, both patients being successfully resuscitated. Endomyocardial biopsy, although occasionally hazardous, may sometimes provide valuable information which may lead to a diagnosis, facilitate treatment, and be of prognostic value. Despite the low positive yield, it may still be indicated in selected patients, in view of the seriousness and often poor prognosis of this disorder: 5 of our study group subsequently died.

Adolescent↗
PubMed1991

Improving subjective decision making in health care administration.

Managing a health care institution typically requires the consideration of many nonquantifiable factors, such as community relations, quality of service, and employee morale. As a result, subjective judgments are an inevitable, and often major, part of decision making in health care financial management. A large body of scientific research has shown that people's subjective, or intuitive, judgments tend to be biased and inaccurate. This article reviews the major types of errors typically found in four phases of decision making: defining the problem, estimating the effects of different alternatives, choosing an alternative, and evaluating the outcomes as the basis for subsequent action. In addition to alerting health care administrators to these potential judgment errors, several methods to improve subjective decision making are explained.

Choice Behavior↗
PubMed1991

Watch for pitfalls of discounted cash flow techniques.

Discounted cash flow (DCF) techniques can enhance the effectiveness of a healthcare organization's capital budgeting decisions. But a financial manager unaware of common misapplications of DCF techniques may make capital decisions with a hidden bias against long-term projects, an inaccurate evaluation of options, or inappropriate estimations of expected inflation and risk. Social and psychological factors also can impede effective decisions on projects already introduced.

Accounts Payable and Receivable↗
PubMed1991

Planning effectiveness may grow on fault trees.

The first step of a strategic planning process--identifying and analyzing threats and opportunities--requires subjective judgments. By using an analytical tool known as a fault tree, healthcare administrators can reduce the unreliability of subjective decision making by creating a logical structure for problem solving and decision making. A case study of 11 healthcare administrators showed that an analysis technique called prospective hindsight can add to a fault tree's ability to improve a strategic planning process.

Bankruptcy↗
PubMed1990

Geleophysic dysplasia.

We describe 2 children with geleophasic dysplasia. Prominent cardiac disease in one of the patients caused death at an early age. The history of consanguinity in one of the families supports autosomal recessive mode of inheritance. Histological and ultrastructural changes suggest that a disturbance in the relations between cell membrane and extracellular matrix may be involved in the pathogenesis.

Abnormalities, Multiple↗
PubMed1990

Autosomal recessive hydrocephalus with third ventricle obstruction.

Here we report a brother and sister who presented in the neonatal period with hydrocephalus. Ultrasonography showed marked dilatation of the lateral ventricles but not the third ventricle. One child with postnatal onset was shunted and had normal development at 3 years. The other child had severe hydrocephalus at birth and was not treated. Neuropathologic studies demonstrated dilatation of the lateral ventricles and marked narrowing of the posterior part of the third ventricle but no other malformations other than those that result directly from hydrocephalus. The potential for a good prognosis is emphasized.

Cerebral Ventricles↗
PubMed1990

Pathology of hepatic peroxisomes and mitochondria in patients with peroxisomal disorders.

The morphology of hepatic peroxisomes in five patients with metabolic disorders believed to be due to inherited defects of peroxisomal function or biogenesis is described. Electron microscopy and cytochemical staining for catalase were used to identify peroxisomes in two boys with infantile Refsum's disease (IRD), a girl with autopsy confirmed neonatal adrenoleukodystrophy (NALD), and two boys with pseudo-Zellweger syndrome (PZS). In the patients with IRD and NALD hepatic peroxisomes were significantly reduced in size and number and contained electron dense centres. In the liver of the patients with PZS the peroxisomes were enlarged. Morphologically abnormal peroxisomes were also detected in autopsy tissue from one boy with PZS using electron microscopy. Lamellar-lipid inclusions and mitochondria with crystalline inclusions and/or abnormal cristae are also described in two patients, one with IRD, the other with NALD.

Adrenoleukodystrophy↗