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Biomedical subjects

C H Ho

Publications and source records attributed to C H Ho.

At least 19 recordsLinked to original sources
PubMed2004

Risk factors associated with habitual snoring and sleep-disordered breathing in a multi-ethnic Asian population: a population-based study.

INTRODUCTION: There is scant data on the risk factors of sleep-disordered breathing (SDB) in the general population in Asian countries. METHODS: Cross-sectional survey of a random population sample of 2298 adults aged 20-75 years, stratified by gender, ethnicity (Chinese, Malay and Indian) and age. An interviewer-administered questionnaire was used to elicit responses to questions on daytime somnolence and nocturnal events. Three categories of SDB were defined for analysis: habitual snoring; apnoeic snoring (SDB I); and apnoeic snoring or snoring with diurnal hypersomnia (SDB II). RESULTS: Snoring was reported by 201 persons (6.8%), SDB-I in 44 (1.9%) and SDB-II in 112 (4.9%) in the sample. The adjusted odds ratio (95% C.I.) of association with snoring were: male gender, 3.79 (2.69-5.33); older age (>60 years old), 2.15 (1.41-3.29); Indian versus Chinese, 1.54 (1.05-2.25); family history, 2.21 (1.56-3.12); obesity (BMI>30), 2.64 (1.62-4.30); neck circumference (>40 cm), 2.57 (1.59-4.11); and cigarette smoking, 2.05 (1.21-3.45). The risk factors for SDB were similar to that of snoring. CONCLUSION: Population risk factors associated with habitual snoring and SDB in Singapore are largely similar to those reported in other populations. Differential risks underscore the importance of ethnicity in determining the burden of SDB.

Adult↗
PubMed2003

A novel splicing acceptor mutation of the factor VIII gene producing skipping of exon 25.

A gross deletion in the factor VIII (FVIII) mRNA was determined by reverse transcriptase polymerase chain reaction (RT-PCR) for a patient with moderately severe hemophilia A. Sequencing of the RT-PCR product depicted a 177-bp deletion ranging from nucleotide (nt) 6724 to nt 6900 of FVIII cDNA, exactly corresponding to the whole exon 25. Further study of the genomic DNA revealed the presence of a single base pair substitution (G >A) at position -1 of intron 24. The absolute consensus AG doublet of the intron 24 splicing acceptor changed to AA. In the novel splice site mutation, exon 24 was erroneously spliced to exon 26, skipping exon 25. The FVIII antigen level was normal despite the markedly reduced functional activity. Since exon 25 corresponds to part of the C2 domain, we speculate that for this patient the aberrant C2 domain markedly reduces binding affinity of FVIII protein to the phospholipid membrane, thus severely impairing the protein function.

Adolescent↗
PubMed2002

Leukopenia and thrombocytopenia in hemodialysis patients with hepatitis B or C virus infection and non-hemodialysis patients with hepatitis cirrhosis.

AIMS: To investigate the relation of leukopenia and thrombocytopenia in hemodialysis (HD) patients with hepatitis C virus (HCV) infection. MATERIALS AND METHODS: The study included 86 HD patients with hepatitis B surface antigen-negative and hepatitis C antibody-negative, 28 HD patients with hepatitis C antibody-positive, 22 HD patients with hepatitis B surface antigen-positive, 78 non-HD patients with hepatitis B-induced liver cirrhosis and 38 non-hemodialysis patients with hepatitis C-induced liver cirrhosis. The following parameters were checked: anti-HCV, hepatitis B surface antigen, hemoglobin, hematocrit, white blood cells, platelets, calcium, phosphate, iron, ferritin, albumin, globulin, aspartate transaminase (AST), alanine transaminase (ALT) and C-reactive protein. The history of blood transfusions, medications, erythropoietin doses and adequate dialysis (KTNV) for 6 consecutive months was also recorded from charts. RESULTS: The HD patients with positive serum anti-HCV and non-HD patients with hepatitis B- or C-induced liver cirrhosis had higher prevalences of leukopenia (39.3%, 43.6% and 50% vs. 15.1%; p < 0.001) and thrombocytopenia (67.9%, 89.7% and 81.6% vs. 34.9%: p < 0.001) than HD patients with serum anti-HCV(-)HbsAg(-). The WBC (4,432 +/- 1,394, 4,792 +/- 2,263 and 4,624 2,446 vs. 5,590 +/- 1,500/mm3; p < 0.001) and platelet counts (140 +/- 45, 80 +/- 50 and 89 +/- 65 vs. 186 +/- 62 x 10(3)/mm3; p < 0.001) of HD patients with positive serum anti-HCV and non-HD patients with hepatitis B- or C-induced cirrhosis were also lower than HD patients without anti-HCV antibody. The liver cirrhosis patients had more thrombocytopenia than the HD patients with anti-HCV(+). The WBC and platelet counts did not vary between HD patients with HbsAg(+) and HD patients with anti-HCV(-)HBsAg(-). The durations of HD, hepatitis and liver cirrhosis were not related to the leukopenia or thrombocytopenia (p > 0.05). CONCLUSIONS: HCV infection associated with leukopenia and/or thrombocytopenia in HD patients is as common as in non-HD patients with liver cirrhosis. This may be due to the direct effect of hemopoiesis rather than the hyperspleenism of liver cirrhosis patients. There is a need for further prospective investigation to ascertain the clinical significance of leukopenia and thrombocytopenia in HD patients with anti-HCV(+). The prevalence of leukopenia and thrombocytopenia was higher in HD patients with hepatitis C than in HD patients with hepatitis B and HD patient without hepatitis.

Adult↗
PubMed2001

Detection of Kaposi sarcoma-associated herpesvirus in bone marrow biopsy samples from patients with multiple myeloma.

BACKGROUND: Kaposi sarcoma-associated herpesvirus (KSHV) recently has been identified in the bone marrow (BM) dendritic cell of multiple myeloma (MM) patients. However, whether or not KSHV is associated with MM remains controversial because many studies have failed to detect the presence of KSHV DNA sequences in the BM of their MM patients. METHODS: We have assayed for KSHV DNA sequences in the BM biopsy samples from 49 patients with MM and from 8 patients with normal BM, using nested polymerase chain reaction and dot blot analysis. The polymerase chain reaction product of KSHV was further determined by single-strand conformation polymorphism and sequence analyses. RESULTS: KSHV DNA was detectable in 22 of 49 patients (44.9%) with MM but was not detectable in normal BM cells. Single-strand conformation polymorphism and sequence analyses showed that there were interpatient specific mutations. Sixteen out of 22 KSHV DNA sequences belonged to a previously defined subgroup, and the other 6 remain unclassified and may represent distinct strains of KSHV in Taiwan. CONCLUSIONS: Data strongly supported that KSHV infection did exist in the BM of the current study patients with MM. However, the role of KSHV in the pathogenesis of multiple myeloma remains to be determined.

Adult↗
PubMed2001

Determination of lewisite oxide in soil using solid-phase microextraction followed by gas chromatography with flame photometric or mass spectrometric detection.

A rapid, sensitive, and convenient method is described for determining Lewisite oxide in soil. Samples are initially fortified with phenylarsine oxide (surrogate), then both species are extracted using ascorbic acid solutions containing 1,3-propanedithiol (derivatizing reagent). The corresponding filtered supernatant is sampled using a solid-phase microextraction fiber. Collected analytes are thermally desorbed in a heated gas chromatographic inlet, separated using fused-silica capillary columns ("primary" and "confirmatory"), and detected with either a mass spectrometric (selected ion monitoring mode) or flame photometric (sulfur-selective mode) detector. Two independent statistically-unbiased procedures were used to evaluate the detection limit for Lewisite oxide; the values range between 0.1 and 0.5 microg g(-1) soil.

Arsenicals↗
PubMed2001

A plant gene encoding a Myb-like protein that binds telomeric GGTTTAG repeats in vitro.

A gene (AtTRP1) encoding a telomeric repeat-binding protein has been isolated from Arabidopsis thaliana. AtTRP1 is a single copy gene located on chromosome 5 of A. thaliana. The protein AtTRP1 encoded by this gene is not only homologous to the Myb DNA-binding motifs of other telomere-binding proteins but also is similar to several initiator-binding proteins in plants. Gel retardation assay revealed that the 115 residues on the C terminus of this protein, including the Myb motif, are sufficient for binding to the double-stranded plant telomeric sequence. The isolated DNA-binding domain of AtTRP1 recognizes each telomeric repeat centered on the sequence GGTTTAG. The almost full-length protein of AtTRP1 does not form any complex at all with the DNA fragments carrying four or fewer GGTTTAG repeats. However, it forms a complex with the sequence (GGTTTAG)(8) more efficiently than with the sequence (GGTTTAG)(5). These data suggest that the minimum length of a telomeric DNA for AtTRP1 binding consists of five GGTTTAG repeats and that the optimal AtTRP1 binding may require eight or more GGTTTAG repeats. It also implies that this protein AtTRP1 may bind in vivo primarily to the ends of plant chromosomes, which consist of long stretches of telomeric repeats.

Amino Acid Sequence↗
PubMed2001

Sequencing and amplified restriction fragment length polymorphism analysis of ribonucleotide reductase large subunit gene of the white spot syndrome virus in blue crab (Callinectes sapidus) from American Coastal Waters.

In the present study, the existence of white spot syndrome virus (WSSV) in blue crab (Callinectes sapidus) collected from 3 different American coastal waters (New York, New Jersey, and Texas) was confirmed by 2-step diagnostic polymerase chain reaction and in situ hybridization analysis. When geographic isolates were also compared using a gene that encodes the WSSV ribonucleotide reductase large subunit RR1 (WSSV rr1), a C(1661)-to-T point mutation was found in the New Jersey WSSV isolated. This point mutation, which resulted in the creation of an additional RsaI endonuclease recognition site, was not found in the WSSV from the New York and Texas blue crab samples, or in the WSSV Taiwan isolate, or in any of the other WSSV geographical isolates for which data are available. WSSV rr1-specific RsaI amplified restriction fragment length polymorphism of an amplified 1156-bp fragment thus distinguished the New Jersey blue crab samples from the other WSSV isolates.

Journal Article↗
PubMed2001

The changes of cardiac ejection fraction up to 72 h after transfusion in patients with chronic anaemia.

The objective was to assess the serial change of the cardiac function after blood transfusion in patients with chronic anaemia. According to a previous study, transfusion would adjust the ejection fraction to the advantage of cardiac function in chronic anaemia patients, and thus the serial change of the cardiac function in a certain period should be evaluated after transfusion in patients with chronic anaemia. In a prospective study, ejection fraction (EF) was determined before and < or = 6 h, 24 h and 72 h after transfusion in 32 patients with chronic anaemia, and the results were compared and analysed. In the left ventricle (LV), the four EFs noted before and < or = 6 h, 24 h and 72 h after transfusion did not significantly differ between one another. In the right ventricle (RV), the EF 72 h after transfusion significantly increased in comparison with the pretransfusion value (P = 0.043). Transfusion of small amounts of RBC did not significantly change the LVEF up to 72 h in patients with transfusion-dependent chronic anaemia; whether it might change the RVEF 72 h after transfusion deserves further investigation.

Adult↗
PubMed2001

Effects of the routine change of chronic indwelling Foley catheters in persons with spinal cord injury.

OBJECTIVE: To determine whether routine catheter changes have any effect on the urinary white blood cell count (WBC) and bacterial culture in asymptomatic individuals with spinal cord injury (SCI) who have indwelling Foley catheters. DESIGN: Prospective case series. SETTING: Urology and SCI outpatient departments of a rehabilitation center. SUBJECTS: Twelve asymptomatic individuals (male and female) with SCI who have chronic indwelling urethral Foley catheters that are changed routinely every month. MAIN OUTCOME MEASURES: Two sets of urinalysis and urinary culture and sensitivity from each individual, one set taken through the Foley catheter before the catheter change and another set after the catheter change. WBC, bacterial identity, and colony count were measured, and the corresponding data were compared. RESULTS: All subjects had pyuria and bacteriuria before and after the catheter change. Analysis of the data showed a statistically significant increase in WBC in the urine after the indwelling Foley catheter was changed (P = .0039). However, bacterial types and corresponding colony counts remained almost completely unchanged. CONCLUSIONS: Routine change of chronic indwelling Foley catheters in asymptomatic individuals with SCI causes a significant rise in the urinary WBC, without altering the bacterial identity or colony count. Pyuria and bacteriuria are prevalent among individuals with SCI (including those who are asymptomatic) with indwelling Foley catheters. This study suggests that urinalysis should be taken before a catheter change.

Bacteriological Techniques↗
PubMed2001

Resveratrol analog, 3,4,5,4'-tetrahydroxystilbene, differentially induces pro-apoptotic p53/Bax gene expression and inhibits the growth of transformed cells but not their normal counterparts.

Resveratrol, a trihydroxystilbene found in grapes and other plants, has been shown to be active in inhibiting multistage carcinogenesis. Using resveratrol as a prototype, we have synthesized a number of polyhydroxy- and polymethoxy-stilbenes and tested their anti-proliferative effect in normal and transformed human cells. Here we show that one of the resveratrol analogs, 3,4,5,4'-tetrahydroxystilbene (R-4), specifically inhibited the growth of SV40 virally transformed WI38 cells (WI38VA) at 10 microM, but had no effect on normal WI38 cells at even higher concentrations. R-4 also prominently induced apoptosis in WI38VA cells, but not in WI38 cells. RNase protection assay showed that R-4 significantly induced the expression of p53, GADD45 and Bax genes and concomitantly suppressed the expression of bcl-2 gene in WI38VA, but not in WI38 cells. A large increase in p53 DNA binding activity and the presence of p53 in the Bax promoter binding complex suggested that p53 was responsible for the Bax gene expression induced by R-4 in transformed cells. Within 4 h of treatment with R-4, the Bax to bcl-2 protein ratio in WI38 and WI38VA cells was, respectively, 0.1 and 105, a difference of three orders of magnitude. While R-4 prominently induced the p53/Bax pro-apoptotic genes, it also concomitantly suppressed the expression of Cox-2 in WI38VA cells. Taken together, our study suggests that the induction of p53 gene by R-4 in transformed cells may play a key role in the differential growth inhibition and apoptosis of transformed cells.

Apoptosis↗
PubMed2001

2-chlorodeoxyadenosine (cladribine) in the treatment of hairy cell leukemia.

Hairy cell leukemia is an uncommon chronic B cell lymphoproliferative disorder in Taiwan and only sporadic cases have been noted. This disease is often found in middle-aged men with the typical manifestations of pancytopenia and splenomegaly. While tartrate-resistant acid phosphatase (TRAP) stain of the neoplastic cells in peripheral blood smear is positive in 90% cases, bone marrow examination is still necessary for diagnosis. For treatment, splenectomy and interferon have been the standard strategies. Recently, newly-developed purine analogues, 2-chlorodeoxyadenosine (cladribine) and 2'-deoxycorfomycin (pentostatin), were found to achieve long lasting complete remission. Here we reported a 48-year-old men who was found to have splenomegaly and bicytopenia incidentally at routine physical checkup. Although the TRAP staining of peripheral blood showed negative result, hairy cell leukemia was finally diagnosed by bone marrow biopsy. The following splenectomy showed a typical picture of hairy cell leukemia on pathology, but cytopenia recovered only partially after surgery. One course of chemotherapy with cladribine (0.1 mg/kg/day continuous intravenous infusion for 7 days) was given after recovery from major surgery. The white cell and platelet counts normalized after treatment and he carried a stable condition thereafter. Since the disease is rare and purine analogues are newly developed, there has been no report on using 2-clorodeoxy-adenosine against hairy cell leukemia in our country. Here we suggest that newly developed purine analogues such as cladribine are the first choice of treatment in cases of hairy cell leukemia.

Antineoplastic Agents↗
PubMed2000

Causes of venous thrombosis in fifty Chinese patients.

In a whole year from July 1997 to June 1998, a total of 50 patients with sonogram-proved venous thrombosis who called on our hematology clinic consecutively entered into the study. Their mean age was 59.1 +/- 17.5 years, range 18-83 years, and 29 were male. A series of examinations were performed in order to find out the cause of venous thrombosis. These examinations included antithrombin, protein C, protein S, plasminogen, heparin cofactor II, activated protein C ratio, factor V Leiden mutation, fibrinogen, factors VIII and XII, euglobulin lysis time, 677 C-->T mutation of methylenetetrahydrofolate reductase (MTHFR), prothrombin 20210 (PT 20210) A allele mutation, lupus anticoagulant, anticardiolipin antibody, and complete blood count. Five patients (10%) were found to have malignancy; an inferior vena cava thrombosis in one patient was due to venous compression by hydronephrosis; two patients had lupus anticoagulant; two had varicose veins of legs; two had protein C deficiency; four had protein S deficiency; two had plasminogen deficiency; two had antithrombin deficiency. No activated protein C resistance, elevated factor VIII level, factor V Leiden, PT 20210 A allele or heparin cofactor II deficiency was found in the present study. Homozygous MTHFR 677 C-->T gene mutation was found in 7 patients (14%); one of them also had a plasminogen deficiency. No possible risk factor of venous thrombosis could be found in 24 patients (48%). In conclusion, malignancy and protein S deficiency were the most frequent acquired and congenital causes of venous thrombosis in the Chinese, respectively.

Adenocarcinoma↗
PubMed2000

Prevalence of prothrombin 20210A allele and methylenetetrahydrofolate reductase C677T genetic mutations in the Chinese population.

From July 1997 to June 1998, a total of 1323 subjects, including 1180 controls, 94 patients with diabetes mellitus, and 49 patients with deep-vein thrombosis, varying in age and gender, were consecutively entered into our study. Their mean (+/- SD) age was 50.0 +/- 18.0 years, range 1-99 years; 930 were male and 393 were female. None of the subjects was found to have abnormal prothrombin 20210A allele mutation. In total, 150 subjects (11.3%) were found to have a homozygous 677 C-->T mutation of the methylenetetrahydrofolate reductase gene, in which 125 were controls (10.6%), 17 were diabetics (18.1%) and 8 were patients with deep-vein thrombosis (16.3%). However, 524 subjects (39.6%) were found to have a heterozygous methylenetetrahydrofolate reductase 677 C-->T mutation. We suggested that the Chinese race dose not have the prothrombin 20210A allele, but can carry the 677 C-->T mutation of the methylenetetrahydrofolate reductase gene.

Adolescent↗
PubMed2000

Angiotropic lymphoma manifesting as a solitary adrenal tumor in a case of ankylosing spondylitis.

Angiotropic lymphoma is an extremely rare disease characterized by intravascular accumulation of large neoplastic lymphocytes, with the clinical manifestations of fever, skin lesions and neurologic deficits. We report a patient who developed angiotropic lymphoma after a 10-year history of ankylosing spondylitis. The clinical disease manifested as a unilateral, solitary adrenal tumor, fever and body weight loss. The fever subsided after surgical removal of the adrenal tumor. Systemic chemotherapy was administered postoperatively. The patient was leading an uneventful life 44 months after the initial diagnosis. To our knowledge, this is the first case of angiotropic lymphoma associated with ankylosing spondylitis. It is also the second reported case manifesting with a unilateral solitary adrenal tumor without systemic involvement.

Adrenal Gland Neoplasms↗
PubMed2000

The influence of age, sex, vitamin B(12), folate levels and methylenetetrahydrofolate reductase C677T genetic mutations on plasma homocysteine in the Chinese population.

BACKGROUND AND OBJECTIVES: Thromboembolic diseases remain a major cause of morbidity and mortality in most countries. The present study was thus conducted to determine the influences of age, sex, the methylenetetrahydrofolate reductase (MTHFR) gene mutation and the B vitamins on the plasma homocysteine (Hcy) levels in the Chinese. Our previous study found that Chinese carry the same mutation of the methylenetetrahydrofolate reductase (MTHFR) gene described in Western populations, with a 677CAET substitution being another possible cause of thrombosis. DESIGN AND METHODS: The study population comprised 445 consecutively enrolled Chinese subjects of different ages and sex. Overall 69 subjects were found to have homozygous 677CAET mutation of the MTHFR gene, and were classified as Group I; 164 subjects were found to have heterozygous mutation and classified as Group II; 212 had no such mutation and were classified as Group III. RESULTS: The mean plasma Hcy did not differ significantly between these 3 groups. When each group was divided again by gender, we found that both age and plasma Hcy levels were significantly higher in the males than in the females. In addition to Hcy levels, we also measured plasma vitamin B(12) and folate levels in 258 randomized subjects. Univariate and multivariate analysis showed MTHFR mutation could affect Hcy level, and univariate and multivariate analysis showed that age, MTHFR mutation and vitamin B(12) could affect the log(Hcy) levels. INTERPRETATION AND CONCLUSIONS: We demonstrate that some Chinese carry the 677CAET mutation of the methylenetetrahydrofolate reductase gene. This could affect their homocysteine levels and thus be a risk factor for thromboembolic disease.

Age Factors↗
PubMed2000

Pyogenic liver abscess--a tropical centre's experience in management with review of current literature.

AIM OF STUDY: To perform a retrospective study, with the help of literature review, of the management of patients with pyogenic liver abscess in a general hospital. METHOD: A retrospective study of 73 consecutive patients treated atTanTock Seng Hospital between January 1994 and December 1997 was conducted to determine the demographic, clinical, laboratory, radiological and microbiological characteristics of these patients, as well as the management strategies employed. RESULTS: Liver abscess was more common in males, occurring more frequently in the right hepatic lobe. Most patients presented with non-specific clinical and biochemical features. A raised alkaline phosphatase level was the most common biochemical abnormality found in about two-thirds of patients. Ultrasonography was not as sensitive as computed tomographic scans in detecting abscesses. Klebsiella pneumoniae was the most common etiological agent detected in cultures of blood and abscess aspirates. All patients were treated with intravenous antibiotics. Twenty-two (30%) needed percutaneous catheter drainage and five (7%) required surgical management. There was no hospital mortality in our series. Prolonged hospitalisation was associated with advanced age, degree of loculation within the abscess, concomitant diabetes mellitus and Klebsiella septicaemia. CONCLUSION: Pyogenic liver abscesses require a high index of suspicion for early diagnosis. When appropriate therapy in the form of antibiotics in combination with percutaenous drainage or surgery is administered, mortality is very low. However, significant morbidity is still a problem, particularly in the elderly, diabetic patient.

Adolescent↗