Propagation and some physiological effects of Citrus bark cracking viroid and Apple fruit crinkle viroid in multiple infected hop (Humulus lupulus L.).

The hop metabolome important for the brewing industry and for medical purposes is endangered worldwide due to multiple viroid infections affecting hop physiology. Combinatorial biolistic hop inoculation with Citrus bark cracking viroid (CBCVd), Apple fruit crinkle viroid (AFCVd), Hop latent viroid, and Hop stunt viroid (HSVd) showed a low CBCVd compatibility with HSVd, while all other viroid combinations were highly compatible. Unlike to other viroids, single CBCVd propagation showed a significant excess of (-) over (+) strands in hop, tomato, and Nicotiana benthamiana, but not in citruses. Inoculation of hop with all viroids led to multiple infections with unstable viroid levels in individual plants in the pre- and post-dormancy periods, and to high plant mortality and morphological disorders. Hop isolates of CBCVd and AFCVd were highly stable, only minor quasispecies were detected. CBCVd caused a strong suppression of some crucial mRNAs related to the hop prenylflavonoid biosynthesis pathway, while AFCVd-caused effects were moderate. According to mRNA degradome analysis, this suppression was not caused by a direct viroid-specific small RNA-mediated degradation. CBCVd infection led to a strong induction of two hop transcription factors from WRKY family and to a disbalance of WRKY/WDR1 complexes important for activation of lupulin genes.

Red cell folate and predicted neural tube defect rate in three Asian cities.

BACKGROUND: Periconceptional folic acid reduces neural tube defect (NTD) risk. Red blood cell folate concentration is inversely associated with NTD risk. In many countries there is a lack of information on NTD rates. Red cell folate status in women of childbearing age may be a surrogate for NTD rates and may be helpful in identifying countries or regions most likely to benefit from improved folate status. OBJECTIVE: To predict NTD rates using red cell folate concentrations in women of childbearing age living in three Asian cities Design: Cross-sectional convenience samples of non-pregnant women living in Beijing (n=220), Kuala Lumpur (n=389), and Jakarta (n=129). RESULTS: Red cell folate concentrations were highest (p<0.001) in women from Jakarta at 872 nmol/L (95% CI; 833, 910) followed by Kuala Lumpur at 674 nmol/L (95% CI: 644, 704) and lowest in Beijing at 563 nmol/L (95% CI: 524, 601). Accordingly, predicted NTD rates were highest in Beijing at 30/10000 (95% CI: 27, 33), followed by Kuala Lumpur at 24/10000 (95% CI: 22, 25), and lowest in Jakarta at 15/10000 (95% CI: 14,15). CONCLUSION: Our red blood cell folate data suggests that of the three cities improving the folate status of women in Beijing would have the greatest impact on NTD rates.

Dietary and blood folate status of Malaysian women of childbearing age.

The protective role of folic acid taken during the periconceptual period in reducing the occurrence of neural tube defects (NTD) has been well documented by epidemiological evidence, randomized controlled trials and intervention studies. Much of the evidence is derived from western populations while similar data on Asian subjects is relatively nascent. Baseline data on folate status of Malaysian women is lacking, while NTD prevalence is estimated as 10 per 10,000 births. This study was conducted with the objective of determining the dietary and blood folate status of Malaysian women of childbearing age. A total of 399 women comprising 140 Malay, 131 Chinese and 128 Indian subjects were recruited from universities and worksites in the suburbs of Kuala Lumpur. Inclusion criteria were that the subjects were not pregnant or breastfeeding, not taking folic acid supplements, not habitual drinkers or smokers. Based on a 24-hour recall, the median intake level for folate was 66 microg (15.7-207.8 microg), which amounts to 16.5% of the Malaysian Recommended Nutrient Intakes level. The median (5-95th percentiles) values for plasma and red cell folate (RBC) concentrations were 11 (4-33) nmol/L and 633 (303-1209) nmol/L respectively. Overall, nearly 15.1% showed plasma folate deficiency (< 6.8 nmol/L), with Indian subjects having the highest prevalence (21.5%). Overall prevalence of RBC folate deficiency (<363 nmol/L) was 9.3%, and an almost similar level prevailed for each ethnic group. Only 15.2% had RBC concentration exceeding 906 nmol/L, which is associated with a very low risk of NTD. The result of this study point to the need for intervention strategies to improve the blood folate status of women of childbearing age, so that they have adequate protection against the occurrence of NTD at birth.

Genotyping of hepatitis B virus in Malaysia based on the nucleotide sequence of preS and S genes.

Hepatitis B virus (HBV) has been classified into eight genotypes, designated A-H. These genotypes are known to have distinct geographic distributions. The clinical importance of genotype-related differences in the pathogenicity of HBV has been revealed recently. In Malaysia, the current distribution of HBV remains unclear. The aim of this study was to determine the genotypes and subtypes of HBV by using PCR, followed by DNA sequencing, as well as to analyse the mutations in the immunodominant region of preS and S proteins. The S gene sequence was determined from HBV DNA of four apparently healthy blood donors' sera and three sera from asymptomatic chronic hepatitis B carriers. Of this batch of sera, the preS gene sequence was obtained from HBV DNA from three out of the four blood donors and two out of the three chronic carriers. Due to insufficient sera, we had to resort to using sera from another blood donor to make up for the sixth DNA sequence of the preS gene. Based on the comparative analysis of the preS sequences with the reported sequences in the GenBank database, HBV DNA from two normal carriers was classified as genotype C. Genotype B was assigned to HBV from one blood donor and two hepatitis B chronic carriers, whereas HBV of one chronic carrier was of genotype D. Based on the S gene sequences, HBV from three blood donors was of genotype C, that of one blood donor and one chronic carrier was of genotype B, and the remaining, of genotype D. In the five cases where both preS and S gene sequences were determined, the genotypes assigned based on either the preS or S gene sequences were in concordance. The nature of the deduced amino acid (aa) sequences at positions 125, 127, 134, 143, 159, 161 and 168 of the S gene enabled the classification of these sequences into subtypes, namely, adrq+, adw2 and ayw2. The clustering of our DNA sequences into genotype groups corresponded to their respective subtype, that is, adw2 in genotype B, adrq in genotype C and ayw in genotype D. Analysis of the point mutations revealed that five of the sequences contained aa substitutions at immunodominant epitopes involved in B or/and T cell recognition. In conclusion, despite the low numbers of samples studied, due to budget constraints, these data are still worthwhile reporting, as it is important for the control of HBV infections. In addition, the genotype and mutational data obtained in this study may be useful for designing new treatment regimes for HBV patients.

The prevalence of MTHFR 677C-->T missense mutation, total plasma homocysteine levels and associated risk factors in Malay subjects.

The missense mutation of the methylenetetrahydrofolate reductase (MTHFR) gene 677C-->T is associated with modest elevation of homocysteine levels. The bio-ecogenetics factors of total homocysteine levels (tHcy) were investigated in a cross sectional study involving 53 randomly selected healthy Malay subjects. Results indicated that the prevalence of the homozygous 677T/T was 3.8% and heterozygous 677C/T was 17.0%. The levels of tHcy was higher in subjects aged more than 50 years (n = 7, 11.53 +/- 4.45 mumol/l) and in males (10.99 +/- 3.77 mumol/l) especially smoking males (12.19 +/- 3.62 mumol/l). THcy levels were low in the 3 pregnant subjects (4.44 mumol/l, p = 0.036) who were under folate supplementation.

Structural analysis of a missense mutation (Val414Phe) in the catalytic core domain of the factor XIII(A) subunit.

Molecular analysis has been performed on a Malaysian patient with a severe bleeding disorder due to factor XIII(A) subunit deficiency. Total mRNA was isolated from the patient's leucocytes and four overlapping segments corresponding to the entire coding region of the A subunit cDNA were amplified by RT-PCR. The cDNA segments amplified efficiently and were of expected size. Direct sequencing of the complete reading frame revealed a single homozygous base change (nt 1327G-T) in exon 10 corresponding to a missense mutation, Val414Phe, in the catalytic core domain of the A subunit monomer. The mutation eliminates a BsaJ1 restriction site and family screening showed that both parents were heterozygous for the defect. The base substitution was absent in 55 normal individuals. Val414 is a highly conserved residue in the calcium-dependent transglutaminase enzyme family. Computer modelling based on 3D crystallographic data predicts that the bulky aromatic side chain of the substituted phenylalanine residue distorts protein folding and destabilizes the molecule. In addition, conformation changes in the adjacent catalytic and calcium binding regions of the A subunit are likely to impair the enzymatic activity of any protein synthesized.

HLA-DR2 haplotypic diversity in populations of South-East Asia, northern China, Melanesia and Australian aborigines using PCR-RFLP for DRB1, DRB5, DQA1 and DQB1. A novel DRB1 allele: DRB1*16022.

The polymorphism of the human leucocyte antigen HLA-DR2 and the heterogeneity of HLA-DR2 class II-related haplotypes (HLA-DRB1-DRB5-DQA1-DQB1) were investigated in four populations of east and south-east Asia (SEA) and five Melanesian populations using TaqI restriction fragment length polymorphism (RFLP) analysis, and the polymerase chain reaction (PCR) amplification-based techniques PCR-RFLP and sequence-specific oligonucleotide (SSO) typing. The haplotype DRB1*1502-DRB5*0101-DQA1*0102-DQB1*0601 was common in Malaysians, Javanese, Thursday Islanders, Madang, Goroka and the Australian Aborigines, while DRB1*16021-DRB5*0101-DQA1*0102-DQB1*0502 was common in the Thai and Thursday Islanders. DRB1*1501-DRB5*0101-DQA1*0102-DQB1*0602 was present at a high frequency in Northern Chinese, Goroka, Watut and Australian Aborigines. The study describes four rare or unusual haplotypes: HLA-DRB1*1501-DRB5*0101-DQA1*0101-DQB1*0601, DRB1*1502-DRB5*0101-DQA1*0101-DQB1*0502, DRB1*1502-DRB5*0102-DQA1* 0102-DQB1*0502 and DRB1*1501-DRB5*0101-DQA1*0101/2-DQB1*0503; the latter two were confirmed by segregation in two Javanese families. A new DR2 allele, initially detected by PCR-RFLP and confirmed by DNA sequencing as DRB1*16022 (previously designated DRB1*16Madang), was seen in a Madang individual. A new HLA-DR2 TaqI RFLP subtype, locally designated as DR15U, is also described. This RFLP subtype segregated in a Javanese family and correlated with a typically SEA haplotype, DRB1*1502-DRB5*0102-DQA1*0101-DQB1*0501. The allele HLA-DR16Thai, determined by TaqI DRB RFLP, was found by PCR-RFLP and SSO typing to correlate with a unique SEA haplotype, HLA-DRB1*16021-DRB5*0101-DQA1*0102-DQB1*0502, and was observed in the Thai, Malaysian, Thursday Islander, Javanese and Northern Chinese populations.

Hepatitis delta virus in intravenous drug users in Kuala Lumpur.

The hepatitis delta virus (HDV) is an RNA containing virus that requires hepatitis B virus (HBV) to supply the envelope proteins. HDV only infect man in the presence of HBV, either as a coinfection or as superinfection in HBV carriers. In the presence of hepatitis B infection, the HDV may cause more severe liver damage than that caused by the hepatitis B virus alone. HDV infection was studied in 44 HBsAg positive serum samples collected from male intravenous drug users sent for screening to the Blood Services Centre (BSC), Hospital Kuala Lumpur (HKL) between 1990 and 1992. The majority (39) were in the 20 to 39 age group. The youngest was 19 years old and the oldest was 61 years old. There were 25 Malays, 13 Chinese, five Indians and one Albanian. Anti hepatitis delta antibody (Anti-HDV) was detected in 15 out of 44 (34%) of the drug addicts. These results shows an increased in delta infection in HBsAg positive intravenous drug addicts compared to the surveillance results in 1985 when no delta antibodies were detected, and the 1986 and 1989 surveillance which showed 17.8% and 20% delta antibody positivity respectively.

Significance of autoimmune haemolytic anaemia and immune thrombocytopenia (Evans' syndrome) in systemic lupus erythematosus.

Patients with systemic lupus erythematosus (SLE) have an extremely variable prognosis and mortality. The purpose of this report is to highlight the importance of looking for lupus parameters in patients with autoimmune haemolytic anaemia (AIHA) and/or immune thrombocytopenia (ITP) as this represents a subgroup of systemic lupus erythematosus (SLE) patients with a fairly good prognosis. We report a case of an 8-year-old Malay boy who was admitted to hospital with fever and gum bleeding. Physical examination revealed a malar rash, oral ulcers, petechial haemorrhages and bruises over the limbs, generalised lymphadenopathy and hepatosplenomegaly. Laboratory investigations confirmed the diagnosis of SLE. The patient's serum showing the presence of antinuclear factor, antiphospholipid antibodies and a biological false-positive test for syphilis. Immunological and haematological parameters were in keeping with combined AIHA and ITP (Evans' syndrome). No organ involvement was present and the patient responded well to corticosteroid therapy. This case demonstrates the importance of making an early diagnosis of SLE with haematological complications, in order to ensure full benefit of therapy and emphasises the good prognosis expected in this subgroup of SLE patients.

Prevalence of hepatitis C virus antibodies in blood donors in Malaysia.

Hepatitis C virus (HCV) is the chief aetiologic agent for the parenterally transmitted Non-A, Non-B (NANB) hepatitis. This preliminary study was done to determine the prevalence of anti-HCV in the blood donor population. Blood from 3,540 donors who donated blood to the Blood Services Centre, Hospital, Kuala Lumpur, from 25th August 1991 to 13th January 1992, was tested for anti-HCV using both the Ortho and Abbott 2nd Generation ELISA test kits. ELISA positive specimens were repeated twice but no confirmatory test was done. There were 53 out of 3,540 (1.49%) blood donors who were repeatedly reactive to anti-HCV by ELISA. We plan to do further tests to confirm the results, using RIBA-2 or Abbott Neutralising test. Twenty eight out of 1,713 (1.63%) Malays, 22 out of 1,373 (1.60%) Chinese and 2 out of 393 (0.50%) Indians had antibodies to HCV. There was no significant difference in prevalence in the different age groups. The majority of donors tested were males (3,511 out of 3,540) of which 53 (1.50%) were anti-HCV positive. Only 29 females were tested and all were negative. To determine infectivity of the anti-HCV positive cases we would like to introduce testing for RNA by polymerate chain reaction (PCR). Screening all donated blood for anti-HCV will decrease, but not totally eliminate, post-transfusion hepatitis.

Haemophagocytosis in dengue haemorrhagic fever: a case report.

Virus associated haemophagocytic syndrome (VAHS), a distinct clinico-pathologic entity, is characterised by systemic proliferation of non-neoplastic histotiocytes showing haemophagocytosis resulting in blood cytopaenia. It has been described in relation to several viruses earlier. Here we describe a young girl who developed this reactive process during the course of dengue haemorrhagic fever (DHF).

Influence of two alpha-globin gene deletions on homozygous beta 0-thalassemia.

The favorable influence of alpha-thalassemia due to a deletion of two alpha-globin genes (alpha-thal-l) on homozygous beta 0-thalassemia in an adult Chinese woman is described. Her clinical and hematologic condition was milder than usually seen in homozygous beta 0-thalassemia. With the help of repeated blood transfusions immediately before delivery she gave birth to a physically healthy baby who had the alpha-thal-l trait due to two alpha-globin gene deletions with Hb Bart's in the cord blood.