Displaying publications 1 - 20 of 58 in total

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  1. Yadav, M.
    MyJurnal
    Human Herpesvirus-6 (HHV-6) infections are ubiquitous in human populations with an antibody prevalence of 30-85 percent in normal adults. The virus in vivo infects T-lympho-cytes, at various stages of differentiation and is cytopathic to host cell during productive infection. In culture the virus is pleiotropic for several established cell lines including T and B lymphocytes, macrophages and neural cells. Primary viral infection occurs mostly in early childhood. The saliva is the primary source of infection. The infection remains clinically silent in majority but it establishes a lifelong latent presence. However, in about 30 percent of infants, probably a varient HHV-6, causes exanthem subitum (roseola infantum). If the primary infection of HHV-6 is delayed until adolescence it is accompanied by clinical manifestation of an Epstein-Barr virus like infectious mononucleosis in some individuals. Depressed host immune functions may reactivate the latent HHV-6 infection and further aggravation of the primary disease. Since the virus is cytopathic to the host cell the presence of HHV-6 in AIDS patients and other lympholiferative disorders may increase the severity and pathogenicity of the primary disease. Antibodies to the HHV-6 are enhanced in autoimmune disorders, chronic fatigue syndrome, progressive lymphoroliferative disorders and organ transplant patients on immunosuppressive drugs therapy. While considerable basic immunovirological information has been obtained in the last 4 years, large gaps in knowledge still exist on the biologic interaction of HHV-6 with the host.
  2. Yadav M
    PMID: 2609207
    Serum IgG levels and complement C3 levels were assayed on Day 0, 1, 3-4, 7 and 56-70 post-treatment with diethylcarbamizine citrate (DEC) in a series to 26 patients with Brugia malayi infection and 6 volunteers without infection. On treatment, the microfilariae were cleared from the blood within 24 hours. The eosinophils decreased dramatically on Day 1 post-treatment but increased rapidly by Day 4 to 7 and then dropped to normal levels in 45 days. The serum IgG mean levels decreased briefly following treatment with DEC but then returned to original levels. However, the complement C3 levels gradually increased over the 2 months period of study reaching statistical significance levels (p less than 0.01) in patients with initial high blood microfilariae. The observation suggests that Brugia malayi infection probably induces a high rate of synthesis of complement C3 and this process continued in the post-treatment phase. Since, DEC treatment did not cause a decrease in complement C3 with the elimination of blood microfilariae, it would appear that the complement C3 is consumed following antibody attachment to the microfilariae as they enter the blood circulation.
  3. Yadav M
    PMID: 1948253
    Serum tumor necrosis factor alpha (TNF) concentration was assayed in 105 patients with nasopharyngeal carcinoma using a sensitive ELISA technique with detection level of 10 pg/ml. The TNF levels were detectable in 45 of 63 (71.4%) patients newly diagnosed for the malignancy and 29 of 42 (69%) patients in remission following treatment with radiotherapy. In 25 normal controls the TNF were less than 10 pg/ml. While TNF may be present in the majority of the patients with the malignant disease, the TNF concentration appeared to have no clinical significance in diagnosis or prognosis of the patients.
  4. Yadav, M., Iyngkaran, N.
    MyJurnal
    The total serum IgE levels in infants and children was quantitated by the radioimmunoassay technique. The serum levels increased from about 300 IUlml in the 2-3 month old infants to about 8000 1U/m1 in the 10-year-old children who were probably infected with intestinal helminths. The total serum IgE levels in infants with cow's milk protein-sensitive entero-pathy were similar in level to those in normal infants. Infants and children with acute gastroenteritis, giardia infection and malnutrition had elevated levels of serum IgE levels. The high serum I gE levels noted in Malaysian children are probably indicative of the pattern in the tropics. (Copied from article).
  5. Yadav, M., Harnam, S.
    MyJurnal
    The total and allergen-specific IgE response of patients with rhinitis, rhinoconjunctivities, rhinitis with asthma and rhinitis with dermatitis was analyzed to a panel of twelve high risk airborne and food allergens. It has been found that this panel will detect 96 percent of the allergen-causing diseases in children. It was found that 26 (76%) of the 34 young patients had a family history for atopy suggesting a high frequency of inheritance of allergic disorders. Elevated total IgE was found in most patients with allergic disease. Positive IgE antibody response to two species of Dermatophagoides mite-allergens was found in 7/12 (58%) patients with rhinitis, 11/11 (100%) patients with rhinoconjunctivitis, 7/9 (78%) cases ofrhinitis with asthma and 3/3 (100%) cases of rhinitis with dermatitis. Some of the patients also responded to food allergens. Food allergy was noted in 4/12 (33%) cases of rhinitis, 11/11 (100%) cases of rhinoconjunctivitis, 4/9 (44%) cases of rhinitis with asthma and 1/3 (33%) cases of rhinitis with dermatitis. Patients with rhinoconjunctivitis who tested positive at high titres for mites invariably had enhanced response for cockroaches, shrimps and crabs suggesting invertebrate antigen cross-reactivity. A few patients however, did not show this type of cross-reactivity although they had high titres of anti-mite IgE antibodies indicating that they responded to non cross-reacting allergen epitopes. Response to multiple allergens appears to be a common feature of most patients with respiratory or skin allergic diseases. The prevalence of multiple target-organ allergy to wide variety offood and environmental allergens complicates the long term management ofpatients with such allergic disorders.
  6. Iyngkaran N, Yadav M
    Med J Malaysia, 1995 Jun;50(2):141-4.
    PMID: 7565183
    The relative efficacy and incidence of hypernatremia of a rice starch based low sodium (sodium of 60 mmol/L) oral electrolyte solution was compared to the standard WHO oral rehydration solution (ORS; sodium 90 mmol/L) in 60 infants with non choleragenic acute diarrhoea. Both solutions were found to be equally effective in correcting dehydration as determined by the respective post hydration weight gain which was 150 +/- 175 gms in the rice starch low sodium ORS group and 164 +/- 125 gms in the standard WHO ORS group. However, the mean frequency of stools was greater and the duration of stay longer in the WHO ORS group compared to the rice starch low sodium group. There were 5 cases of hypernatremia in the WHO ORS group as opposed to only one in the rice starch low sodium ORS group. The present study shows that a rice starch low sodium ORS was as effective as the standard WHO ORS and had a lower incidence of hypernatremia in the fluid and electrolyte management of infants with non choleragenic diarrhoea.
  7. Iyngkaran N, Yadav M
    J Trop Pediatr, 1998 08;44(4):199-203.
    PMID: 9718904 DOI: 10.1093/tropej/44.4.199
    Rice-starch based oral rehydration solution (ORS) has been shown to be a suitable alternative to glucose-based ORS in the treatment of both choleragenic and non-choleragenic dehydration in older infants and children. However, in young infants, the wider use of rice-starch ORS has been impeded because of theoretical concern about the poor digestibility of starch. The present study was conducted to evaluate the safety and efficacy of rice-starch ORS in the rehydration of acute diarrhoeal dehydration in infants below 6 months of age. Sixty-three infants with clinical features of acute gastroenteritis were randomly allocated to two groups. Group A, comprising 31 infants, received a rice-starch ORS and group B, comprising 32 infants, received a glucose-based ORS. The response to treatment was monitored by weight gain, stool frequency, and decrease in vomiting. The mean weight gain in moderately dehydrated and mildly dehydrated infants in both groups A and B were closely similar at 12, 24, and 48 h after treatment with the respective ORS solution. The infants without dehydration receiving rice-starch ORS had significantly greater weight gain at 12 h compared to those receiving glucose ORS. However, this difference was not observed at 24 and 48 h. The results of this study show that rice-starch ORS is as safe and efficacious as glucose-based ORS in young infants.
  8. Yadav M, Iyngkaran N
    Med J Malaysia, 1982 Sep;37(3):239-44.
    PMID: 7177005
    Eighteen infants clinically suspected to be intolerant of cow's milk were placed on a milk-free formula and six to eight weeks later were orally challenged with cow's milk. Following challenge three groups were recognised. Group A: Four infants tolerated oral feeds ofcow's milk and lacked mucosal abnormality or clinical symptoms. Group B: Seven infants had mucosal deterioration but lacked clinical symptoms and tolerated cow's milk. Group C: Seven infants had mucosal abnormality, developed clinical symptoms and were intolerant of cow's milk. The intestinal transudation of IgA was increased in Group A and unchanged in Group Band C : the IgM levels in the duodenal juice was increased in Group A and B but unchanged in Group C : the IgG levels in the juice were increased in all Groups following challenge. It appears that increased transmission of IgA and IgM or IgM alone in the duodenal juice is associated with lack of development of clinical symptoms. Symptoms are present in infants in whom the IgA and IgM levels in duodenal juice remained unchanged after challenge. It is suggested that patients responding to cow's millt challenge with intestinal production of IgA and IgM (or IgM alone) are able to counter balance the deleterious mechanisms leading to clinical cow's milk intolerance whereas those who, for some unknown reason, do not mount a secretory immune response become ill.
  9. Yadav M, Prasad U
    PMID: 6095462
    The antibody titres to P. falciparum and Epstein-Barr Virus-associated antigens were assayed in 22 patients with NPC and 43 controls. All, but one patient had antimalarial titres; 14 had titres greater than 80 and 4 patients greater than 640. Compared to controls the mean anti-malarial titre for most age groups were higher in the patients. Those patients with high anti-malarial titres also had high IgA anti-VCA titre, an antibody which has been demonstrated to be diagnostic for NPC. The peak anti-VCA (IgG) and anti-EA (IgG) antibody titres were associated with anti-falciparum titres of 320-640 and 80-160, respectively. The results are discussed in relation to the possible association between malarial infection and etiology of NPC.
  10. Iyngkaran, N., Yadav, M., Boey, G.B., Davis, K.
    MyJurnal
    Estimation of oligosaccharidases in the jejunal mucosa is useful in the diagnosis and evaluation of primary and secondary oligosaccharide intolerance. Until recently these enzymes have been estimated by the method of Dahlgvist.4While the method is accurate and reliable it is tedious and cumbersome. We describe here a semi quantitative method, using the glucose analyser. (Copied from article).
  11. Pévet P, Yadav M
    Cell Tissue Res, 1980;210(3):417-33.
    PMID: 7407847
    The ultrastructure of the pinealocytes of the Malaysian rat (Rattus sabanus), a mammal inhabiting a zone near the equator where the annual variations of daylength are inconspicuous, was examined and compared with that of pinealocytes of other mammals. On the basis of the presence of granular vesicles, only one population of pinealocytes was found. A large number of granular vesicles and vesicle-crowned rodlets is characteristic of the pinealocytes of this equatorial species. Vesicle-crowned rodlets are especially numerous in the endings of the pinealocyte processes and; they most often found in direct topographical connection with the perivascular spaces. The physiological significance of the presence of such large amounts of vesicle-crowned rodlets and of the secretory process characterized by the formation of granular vesicles is discussed.
  12. Yadav M, Padmanathan A, Arivananthan M
    J Obstet Gynaecol, 1997 Jan;17(1):86-7.
    PMID: 15511780
    Introduction It is widely accepted that certain 'high risk' human papillomavirus (HPV) genotypes, particularly HPV 16 and 18 are aetiological agents in the development of neoplasia of the uterine cervix. The long latent period between initial HPV infection and emergence of carcinoma suggests that HPV alone is insufficient for malignant transformation and additional factors are required for the progression of HPV infected cells to a neoplastic phenotype. Cells with integrated HPV express viral E6 and E7 oncoproteins which are crucial for immortalisation of epithelial cells via their action on host p53 protein. It is therefore of particular interest to elucidate the molecular mechanisms that alter the expression of E6/E7 proteins during HPV-associated tumorigenesis. Recently, human herpesvirus-6 (HHV-6) has been shown to infect a HPV-immortalised cervical epithelial cell line and transactivate HPV 18 promoters, upregulating gene expression of E6 and E7 HPV oncoproteins (Chen et al., 1994; DiPaolo et al., 1994). HHV-6, first isolated from peripheral blood mononuclear cells of patients with AIDS and lymphoproliferative disorders, is the causative agent of exanthem subitum, heterophile-negative infectious mononucleosis and other febrile illnesses. HHV-6 has recently been detected in oral carcinomas (Yadav et al., 1994). HHV-6 also contains DNA sequences which can transform epithelial cells in culture.
  13. Yadav M, Arivananthan M, Kumar S
    Clin Diagn Virol, 1996 Oct;7(1):23-33.
    PMID: 9077427
    BACKGROUND: Human herpesvirus type 6 (HHV-6), an ubiquitous virus, is the causative agent for exanthem subitum. The virus is frequently associated with lymphoproliferative disorders and other diseases. Recently, we have reported the frequent presence of HHV-6 in oral carcinoma and the present study extends the observation to cervical carcinoma.

    OBJECTIVE: To examine the presence of HHV-6 in cervical carcinoma.

    STUDY DESIGN: Formalin-fixed, paraffin-embedded cervical carcinoma tissues were examined for the presence of HHV-6 by immunohistochemistry using two monoclonal antibodies that react to HHV-6-encoded p41/38 and gp116/64/54. In situ hybridization with variant-specific probes were used to type the HHV-6 DNA sequences present.

    RESULTS: A total of 14/26 (53.9%) carcinoma tissue specimens and 5/8 (62.5%) normal tissue specimens were positive for viral antigens. In situ hybridization studies revealed the presence of HHV-6 DNA sequences in 10/26 (38.5%) carcinoma tissue specimens and 1/8 (12.5%) normal tissue specimens. In the normal tissue, the HHV-6 was present in the endocervical ciliated columnar-epithelial cells and some cells in the subepithelial mucosa but in the carcinoma, the transformed cells were positive for the virus.

    CONCLUSIONS: HHV-6 viral proteins and DNA were found in more than one third of the cervical tissue examined suggesting possible viral expression in these tumours. The significance of the distribution and role of the HHV-6 in cervical tissue remains unclear. Since HHV-6 has an oncogenic potential, the virus may cooperate with other transforming agents for the progression of the disease.

  14. Norhanom AW, Yadav M
    Br. J. Cancer, 1995 Apr;71(4):776-9.
    PMID: 7710943
    Herbal medication has been practised by the rural Malaysian Malays for a long time. However, the long-term side-effects have never been studied. In the present study, 48 species of Euphorbiaceae were screened for tumour-promoter activity by means of an in vitro assay using a human lymphoblastoid cell line harbouring the Epstein-Barr virus (EBV) genome. Twenty-seven per cent (13 out of 48) of the species tested were found to be positive, and in four species, namely Breynia coronata Hk.f, Codiaeum variegatum (L) Bl, Euphorbia atoto and Exocoecaria agallocha, EBV-inducing activity was observed when the plant extracts were tested at low concentrations of between 0.2 and 1.2 micrograms ml-1 in cell culture. This observation warrants attention from the regular users of these plants because regular use of plants with tumour-promoting activity could well be an aetiological factor for the promotion of tumours among rural Malaysian Malays.
  15. Yadav M, Umamaheswari S, Ablashi D
    J Med Virol, 1991 Apr;33(4):236-9.
    PMID: 1649908
    A total of 234 sera from healthy Malaysians of diverse ethnic origins were tested for antibody to the Z29 and prototype GS strains of HHV-6. The prevalence in the races ranged from 58 to 80% for the GS strain and 49 to 76% for the Z29 strain. The highest prevalence was in Malays with semi-urban cultural lifestyles and lowest was in the indigenous rural tribes (Ibans, Kadazans, Bidayuhs, and Orang Asli). The antibody titres to GS and Z29 virus capsid antigens differed in 11 (4.7%) samples by more than 2 dilutions. In 9 of the 11 sera the titres to GS strain were higher than to the Z29 strain. The differences in the antibody titres between strains of HHV-6 may reflect subtle changes in antigen structure of the virus recognised by some individuals.
  16. Yadav M, Nagappan N, Iyngkaran N
    J Pediatr, 1980 Mar;96(3 Pt 1):515-6.
    PMID: 7359251
  17. Naidu AJ, Yadav M
    J Med Microbiol, 1997 Oct;46(10):833-8.
    PMID: 9364139
    Aeromonas hydrophila strains obtained from diarrhoeal samples of human patients (19 isolates) and freshwater ponds (11 isolates) were analysed for siderophore production. Both clinical and environmental isolates showed significantly increased siderophore production under iron-limiting conditions both at 28 degrees C and at 37 degrees C. Clinical isolates consistently produced higher levels of siderophores than did the environmental isolates. The role of plasmids in moderating siderophore production was studied after curing with acridine orange. Treatment with acridine orange for 24 h removed the larger plasmids but the smaller plasmids (< 5 MDa), more common in the environmental isolates, were resistant to curing. As found in the untreated isolates, the cured clinical isolates produced higher mean levels of siderophores than the cured environmental isolates. Siderophore production in A. hydrophila was significantly influenced by iron-limiting cultural conditions and the source of isolates, but plasmid content and growth temperature at 28 degrees C or 37 degrees C had little effect on production. The basis for the greater production of siderophores in clinical isolates than in environmental isolates needs further study.
  18. Yadav M, Shah FH
    Lancet, 1973 Aug 25;2(7826):450-1.
    PMID: 4124938
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