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Biomedical subjects

M H Chang

Publications and source records attributed to M H Chang.

At least 91 records · Page 5Linked to original sources
PubMed1997

Putaminal petechial haemorrhage as the cause of chorea: a neuroimaging study.

OBJECTIVES: A hyperintense putamen on either CT or MRI as a finding associated with chorea has occasionally been described and is almost always associated with non-ketotic hyperglycaemia. The cause of the hyperintensity of the striatum in these images is still controversial. Some reports have found that calcification was responsible whereas others have advocated petechial haemorrhage as the cause. The purpose of this study was to determine whether hyperintense striata are caused by petechial haemorrhage or calcification, with the sequential imaging changes. SUBJECTS AND METHODS: Five patients presenting with an acute onset of either hemichorea or generalised chorea and showed either unilateral or bilateral hyperdense striatum on the initial CT were assessed. Neuroimaging studies including sequential CT and MRI examinations and detailed biochemical tests were performed. RESULTS: Three patients had pronounced hyperglycaemia and the other two patients had no biochemical abnormalities. In all patients, the first CT scans, performed within two weeks of the onset of chorea, showed a high density over the striatum contralateral to the chorea, which diminished or disappeared two months later. T1 weighted imaging disclosed hypersignal intensities over the striatum contralateral to the chorea on admission which diminished two months later. T2 weighted imaging at two months showed hyposignal intensity changes corresponding to the area with hypersignal changes on T1 weighted images, implying haemosiderin deposition. CONCLUSION: Based on the evolution of clinical manifestations and the findings of neuroimaging, putaminal petechial haemorrhage might be a new entity causing either hemichorea or generalised chorea.

Aged↗
PubMed1997

Hepatitis G virus infection in normal and prospectively followed posttransfusion children.

A recently identified RNA virus, hepatitis G virus (HGV), has been investigated for its role in causing non-A-E hepatitis. The frequency and clinical outcome of HGV infection in children was studied. Two hundred apparently healthy children aged 6 mo to 12 y, and 90 children who had undergone open heart surgery in a prospective study for posttransfusion hepatitis were included in this study. The serum samples were tested for HGV RNA by nested reverse transcription-PCR with primers from the 5'-untranslated region. The HGV RNA viremic rate was found to be 1% (2/200) in apparently healthy children, 30% in children after open heart surgery. Among the 90 children, three were HGV-infected before the surgery. Twenty-four (28%) of the remaining 87 children tested positive for HGV RNA within 6 mo after the surgery. Sixty-five percents of these viremic children eventually became persistently infected at 1 y after surgery. No HGV RNA-positive children exhibited elevated alanine aminotransferase levels during the follow-up period. No coinfections of HGV with the hepatitis C virus or hepatitis B virus were found. Patients of younger age appeared more likely to become chronic carriers. Anti-HCV screening did not reduce the prevalence of HGV infection. In conclusion, in children with open heart surgery, the risk of transfusion-transmitted HGV infection and the chronicity rate have been found to be high. Young age is a risk factor of persistent infection.

Case-Control Studies↗
PubMed1997

Traumatic dissection of the vertebral artery: a case report.

This report concerns a patient suffering from a severe neck pain on the third day after a traffic accident. This condition was followed by a lateral medullary infarction on the next day. One week later, he was transferred to this hospital and dissection of the vertebral artery was disclosed. It should be emphasized that in case of acute cervical spine injury or severe neck pain after a major trauma, vertebral artery dissection should be considered, as its early diagnosis may have crucial therapeutic implications. In addition, the advantages of the combination of magnetic resonance imaging and magnetic resonance angiography as diagnostic tools-of-choice are emphasized.

Accidents, Traffic↗
PubMed1996

Seroepidemiology of hepatitis B virus infection in children: Ten years of mass vaccination in Taiwan.

OBJECTIVE: To study the seroepidemiology of hepatitis B virus (HBV) infection in children 10 years after a mass hepatitis B vaccination program was begun in Taiwan. DESIGN: Cross-sectional seroprevalence survey. SETTING: Cheng-Chung/Chung-Cheng District, Taipei, Taiwan, 1994. SUBJECTS AND METHODS: Serum samples from 1515 healthy children younger than 12 years were tested for HBV markers. The results were compared with a baseline seroepidemiologic study conducted just before the vaccination program was launched in 1984 and with a subsequent study in 1989 in the same area. MAIN RESULTS: Eighty-seven percent of the children had received at least 3 doses of HBV vaccine. The overall prevalence rate of hepatitis B surface antigenemia decreased from 9.8% in 1984 to 1.3% in 1994. A statistically significant decrease was observed in every age group from 1 to 10 years. The overall prevalence rate of hepatitis B core antibody was 26% in 1984, 15% in 1989, and 4.0% in 1994. This suggests that the risk of horizontal HBV infection has decreased over time, not only because of the protective effect of the vaccine but also because the infection source has diminished. A high prevalence rate of hepatitis B surface antibody (79%) was noted in 1994 as anticipated. CONCLUSIONS: The Taiwanese mass vaccination program has protected most children younger than 10 years from becoming carriers, reducing both perinatal and horizontal HBV transmission. Mass HBV vaccination has proved to be a successful method to control HBV infection in this hyperendemic area.

Child↗
PubMed1996

Humoral and cellular immune responses to hepatitis B vaccination in hepatitis B surface antigen-carrier children who cleared serum-hepatitis B surface antigen.

The immune responses to hepatitis B vaccine were studied in 11 hepatitis B surface antigen (HBsAg) carrier children who had cleared HBsAg but failed to develop hepatitis B surface antigen antibodies (anti-HBs) in sera (group 1), 5 HBsAg carrier children who had cleared HBsAg and developed detectable anti-HBs in sera (group 2), and 5 healthy subjects seronegative for all hepatitis B virus (HBV) markers (group 3). After receiving three doses of HB vaccine, group 1 subjects failed to develop detectable anti-HBs. Subsequently, each subject of the three groups was given one dose of the same vaccine for a cellular immunity study, and a measurable proliferation of peripheral blood mononuclear cells (PBMC) to HBsAg was detected in 1 of 8 (12.5%), 0 of 5, and 4 of 5 (80%) of the cases in each group, respectively, after vaccination. The removal of CD8+ cells enhanced the HBsAg blastogenic response in group 3 but did not reverse the unresponsiveness in group 1 and group 2 subjects. The addition of interleukin (IL)-2 in culture reversed unresponsiveness in all cases except one case in group 1. Compared with before vaccination, PBMC from group 2 subjects produced significantly less interferon gamma (IFN-gamma) and more IL-4 in response to HBsAg after vaccination, a cytokine response not observed in group 1 subjects. HLA typing indicated that 3 of 10 patients in group 1 (30%) and 1 of 5 patients in group 2 (20%) had HLA-DRw14-DRw52, a marker previously linked to low anti-HBs response to hepatitis B vaccine in Taiwan. We conclude that the underlying causes of poor anti-HBs response in group 1 subjects are multifactorial, including specific failure of antigen presentation or T-cell activation, or the lack of T helper (Th)2 cell-like response to HBsAg. HLA-DRw14-DRw52 does not confer absolute nonresponsiveness to HBsAg. These patients are not benefited by hepatitis B immunization.

Adolescent↗
PubMed1996

Necrotizing bowel lesions complicated by Pseudomonas septicaemia in previously healthy infants.

UNLABELLED: Two previously healthy infants with Pseudomonas septicaemia presented with necrotizing bowel lesions. Necrotizing bowel lesions should be suspected when infants presenting with a history of diarrhoea, develop abdominal distension and toxic signs. Pseudomonas aeruginosa should be regarded as one of the important aetiologies in such disorders, especially if there is associated neutropenia and ecthyma gangrenosum-like lesions. Antibiotics must be able to cover this pathogen to avert a catastrophic outcome. CONCLUSION: The intestine should be considered a possible site of involvement in Pseudomonas sepsis and special attention should be paid to examination of the abdomen.

Enterocolitis, Pseudomembranous↗
PubMed1996

Molecular cloning and nucleotide sequence determination of three envelope genes of classical swine fever virus Taiwan isolate p97.

A strain of classical swine fever virus (CSFV) has been isolated in Taiwan. The cDNA coding for three envelope glycoproteins E1, E2 and E3 were molecularly cloned from purified viral particles using the reverse transcription-polymerase chain reaction (RT-PCR) method and sequence-specific primers. The resulting PCR products (1113 bp for E1. 699 bp for E2 and 567 bp for E3) were cloned into the SmaI site of pUC19 and then subjected to DNA sequence analysis. Data showed that nucleotide sequence of the three envelope genes shared a 82-83% homology with the corresponding genes of three other strains (Alfort, Brescia and Weybridge). However, the homology of the deduced amino acid sequence was greater than 90% among the four strains. The potential asparagine-linked glycosylation sites for E1 (5 sites), E2 (7 sites) and E3 (2 sites) were conserved. This suggests that the Taiwan p97 strain is distinct from other three strains described. The variations may have implications for future vaccine development. The sequence has been submitted to GenBank. The accession numbers are U43924 and U03290.

Amino Acid Sequence↗
PubMed1996

The role of transplacental hepatitis B core antibody in the mother-to-infant transmission of hepatitis B virus.

AIMS/METHODS: To investigate the influence of transplacental hepatitis B core antibody (anti-HBc) on perinatal hepatitis B virus (HBV) transmission, we studied the anti-HBc titers in 294 mother-neonate pairs. RESULTS: The anti-HBc titer was highest (10(5.13 +/- 0.80) to 10(4.36 +/- 0.97) in mothers, 10(5.13 +/- 0.76) to 10(5.52 +/- 0.98) in infants) in the 200 hepatitis B e antigen (HBeAg) positive hepatitis B surface antigen (HBsAg) carrier mothers and their infants, second highest (10(4.51 +/- 0.76) and 10(4.68 +/- 0.76)) in the 60 HBeAg-negative HBsAg carrier mothers and their infants, and lowest (10(3.11 +/- 0.76) and 10(3.24 +/- 0.83)) in the 34 non-carrier mothers and their infants (p < 0.05). One hundred and ninety-two infants of HBeAg-positive carrier mothers received hepatitis B immunoglobulin as well as hepatitis B vaccines, and were followed prospectively from birth. Ten infants became HBsAg carriers, and their mothers had significantly lower anti-HBc titers than those of the mothers of 182 infants who did not become carriers (p = 0.003), while maternal serum hepatitis B virus DNA levels (29.9 +/- 23.6 versus 39.9 +/- 58.1 pg/10 ml) did not differ in those two groups (p > 0.25). The same trend was observed in the infants' anti-HBc titers in those two groups (p = 0.0006). CONCLUSIONS: The association of lower anti-HBc titers in HBeAg-positive carrier mother-infant pairs and the development of carrier status in the infants suggests a positive role of anti-HBc in the modulation of mother-to-infant transmission of HBV. A high maternal anti-HBc level in serum may be a negative predictor of immunoprophylaxis failure in high-risk infants.

Child↗
PubMed1996

Case report: paucity of interlobular bile ducts in Chinese children.

Sixteen Chinese children with cholestasis since early infancy were diagnosed to have paucity of interlobular bile ducts (PILBD) or its equivalent. Twelve children belonged to the syndromic group of PILBD and four children belonged to the non-syndromic group. A definite histological diagnosis of bile duct paucity was established in only two children (aged 4 and 9 months) during the first percutaneous needle biopsy. In the remaining 14 children a varying degree of bile duct destruction was evident in the follow up percutaneous or wedge liver biopsies. The evolving changes were characterized by inflammatory infiltration near or at the ductal wall, the presence of dysmorphic ductules, the degeneration of ductal epithelia and a progressive decrease of interlobular bile ducts. Of 10 children who underwent laparotomy for definite diagnosis, kasai operation was performed in two of them. In the syndromic PILBD group, all children, including two paired siblings, had at least three of five major clinical features. Hypoplasia of the extrahepatic biliary tree was found in five children and atresia of the extrahepatic bile duct was found in one. Three of six children studied were shown, by polymerase chain reaction, to have cytomegalovirus infection in the liver. This study demonstrates that bile duct paucity is a result of progressive bile duct destruction. A definitive diagnosis is difficult to make in early infancy. Thus, the careful evaluation of extrahepatic features in cholestatic children and follow-up liver biopsies are indicated. Although the pathogenetic mechanism of PILBD is unknown, bile duct destruction is the common pathway leading to paucity of bile ducts irrespective of syndromic or non-syndromic types.

Bile Ducts↗
PubMed1996

MELAS syndrome associated with a tandem duplication in the D-loop of mitochondrial DNA.

We describe a family with two cases of adult-onset mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome. Interestingly, the proband also had non-insulin dependent diabetes mellitus and hyperthyroidism. Endocrinological studies demonstrated a high titer of TSH receptor antibody in the proband and elevated levels in her maternal relatives. Analysis of mitochondrial DNA (mtDNA) showed an A-to-G transition at nucleotide position 3243 in the tRNA (Leu(UUR)) gene (A3243G) in the three generations of the family. Furthermore, a previously described -260 bp tandem duplication in the D-loop region of mtDNA was also found in the proband and her maternal relatives. To our knowledge, such kind of duplication has never before been reported in the MELAS syndrome. The proportions of mtDNA with the -260 bp tandem duplication and A3243G point mutation were 12.5% and 82% in the muscle, respectively, and 1.6% and 35% in the blood cells, respectively, of the proband. We conclude that the hyperthyroidism in this MELAS patient may be related to the tandem duplication in the D-loop of mtDNA. This study further substantiates the importance of searching for additional genetic mutations in mitochondrial encephalomyopathic patients with new clinical phenotypes.

Adult↗
PubMed1996

Non-ketotic hyperglycaemic chorea: a SPECT study.

OBJECTIVE: To study regional blood flow of the striatum in non-ketotic hyperglycaemic choreic patients. METHODS: Brain SPECT was performed with intravenous injection of 20 mCi 99mTc hexamethylpropylene amineoxime in six non-ketotic hyperglycaemic choreic patients and 10 age matched patients with a similar level of hyperglycaemia without chorea as a control. The focal perfusion defects were analysed by visual interpretation and semiquantitative determination with reference to homolateral occipital blood flow. RESULTS: The measured blood flow of striatum on the contralateral side of chorea was significantly decreased. CONCLUSIONS: Hypometabolism of the striatum is seen not only in Huntington's disease, but also in non-ketotic hyperglycaemic chorea. Hypofunction of the striatum is a possible common pathogenesis in the development of contralateral chorea in different diseases. Furthermore, the sensitivity and reliability of SPECT is as good as PET in assessing choreic patients.

Aged↗
PubMed1996

Hepatitis C viral infection in thalassemic children: clinical and molecular studies.

To determine and correlate the liver function profile, hepatitis C virus (HCV) genome, anti-HCV, genotypes, quantitation, and nucleotide sequence variability in polytransfused thalassemic children, 61 such children were studied prospectively for 4 y. Twenty-six had HCV infection. The average age, number of transfusions, and alanine aminotransferase (ALT) levels of the HCV-infected group were higher than those of the 35 children without HCV infection. None was infected after the initiation of anti-HCV screening in donor blood. Liver biopsies were performed in six HCV-infected and eight HCV-noninfected thalassemic children, and portal fibrosis was found more frequently in the HCV-infected group. Quantitation of HCV RNA was done by the competitive polymerase chain reaction method, and the titer was about 1 x 10(6) to 5 x 10(8) copies/mL. The titer did not change significantly over the 4-y follow-up period and did not correlate with ALT levels. Nineteen HCV-infected patients were genotyped; 15 were Okamoto/Simmonds type II/1b, two were type III/2a, and two were type IV/2b. The hypervariable region of the HCV genome (E2/NS1) was cloned and sequenced in two serum samples from one patient collected at a 2-y interval, as the ALT levels decreased. The variation rate was estimated to be 1.2-1.7 x 10(-2)/nucleotide/y. The results showed that, in polytransfused thalassemic children, 43% (26/61) contracted HCV. We conclude that HCV infection may cause elevated ALT levels and portal fibrosis of the liver, whereas the viral titer and genotypes do not parallel ALT levels.

Adolescent↗
PubMed1996

Home parenteral nutrition in children.

From 1985 to 1994, home parenteral nutrition (HPN) was used as the method of feeding nine pediatric patients. Indications for HPN included congenital or acquired short bowel syndrome. Crohn's disease, chronic intractable diarrhea, chronic idiopathic intestinal pseudo-obstruction and Hirschsprung's disease. During the period, two patients died; one of sepsis and the other from hepatic failure. Three of the remaining patients have since moved on to oral feeding, but four patients continued on HPN. The majority of these patients have attained a normal weight and height for age while receiving HPN. All patients were fed via an implanted silicone catheter. Catheters were removed and replaced due to complications including nine episodes of infection, four episodes of occlusion, three episodes of breakage and two episodes of dislodgement. Catheter-related sepsis was the most common cause of morbidity and hospital readmission in patients receiving HPN, but was acceptably rare. Staphylococcus aureus was the most frequently cultured organism from either the catheter tip or the blood. HPN is a relatively safe feeding method for patients who would otherwise remain hospitalized for prolonged periods on parenteral nutrition for permanent or prolonged intestinal failure.

Adolescent↗
PubMed1996

Hepatitis B virus infection in children: epidemiology, natural course and prevention in Taiwan.

Although most hepatitis B virus (HBV) related chronic liver diseases manifest themselves in adulthood, HBV infection usually begins in infancy or early childhood in hyperendemic areas. The following factors affect the natural course of HBV: 1) host factors: a) initial age of infection: the younger the patient at infection, the more chance the disease will run a chronic course. Immune tolerance to hepatitis B e antigen (HBeAg) and core antigen persists for a period of time in young children. b) the immune status of the host: the usage and tapering of immunosuppressants may induce a severe course with a fatal outcome; 2) maternal carrier status: children of HBeAg seropositive mothers are more immune tolerant to HBV, and thus have lower rates of HBeAg and hepatitis B surface antigen (HBsAg) seroconversion; and 3) viral factors: mutations of the HBV precore, core or core promoter genes are related to fulminant hepatitis B or severe chronic hepatitis B. However, this is a matter of contention. Since July 1984, a nationwide HBV vaccination program has been successfully conducted in Taiwan. In 1994, the HBsAg carrier rate in Taipei city was reduced to < 1% in children younger than 10 years of age. Continuous efforts in immunoprophylaxis will hopefully further reduce the incidence of hepatitis and hepatocellular carcinoma in the next generation.

Adolescent↗
PubMed1996

Mother-to-infant transmission of hepatitis C virus.

Mother-to-infant (vertical) transmission of hepatitis C virus (HCV) has been documented but vertical transmission of HCV is less efficient (affecting 0% to 15% [mean 4.7%] of the infants of mothers with HCV infection) than that of hepatitis B virus. This lower rate of vertical transmission is likely due to the lower viral level of HCV in the sera of most mothers with an infection. Infants of mothers with an HCV and HIV coinfection or with a high HCV RNA titre (greater than 1 million copies per millilitre) are at a high risk of HCV infection (with a mean 39% of infants of mothers with HCV and HIV coinfection having an HCV infection). In most infants (81%) with an HCV infection studied longitudinally, the infection is persistent, and the alanine aminotransferase levels are transiently or persistently abnormal; however, normal liver function is also observed in some patients. There is currently no effective way to prevent vertical transmission of HCV. Further investigation aimed at better understanding the natural history of perinatal HCV infection and the indications for antiviral therapy is needed.

Female↗
PubMed1996

Hepatoblastoma in an infant with Beckwith-Wiedemann Syndrome.

A 3-month-old Chinese male infant with typical manifestations of Beckwith-Wiedemann Syndrome (BWS), such as macroglossia, hepatomegaly, umbilical hernia and hypoglycemia, presented with a large hepatic tumor. The tumor measured 7.6 x 8.0 x 7.5 cm. An open biopsy of the tumor revealed hepatoblastoma. The family refused chemotherapy, so only supportive care was given. The tumor grew very rapidly and the infant died 17 days after admission due to respiratory failure. To our knowledge, this is the first report of BWS associated with hepatoblastoma in a Chinese infant. This patient was a typical example of the association of BWS and hepatoblastoma, and the possible effect of growth factors on the rapid proliferation of the neoplasm in BWS.

Beckwith-Wiedemann Syndrome↗