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Biomedical subjects

K Hassan

Publications and source records attributed to K Hassan.

At least 73 records · Page 4Linked to original sources
PubMed1987

Antibody isotypes in human schistosomiasis mansoni.

Schistosoma mansoni-infected subjects from the Gezira Irrigated Area of Sudan were studied for serum immunoglobulin levels, and specific antibody titres to larval, adult and egg stage antigens, by class and IgG subclass. The 276 subjects were adult chronic cases (frequently exposed male canal cleaners), primary school children, and hospital-referred cases with acute symptoms including hepatosplenomegaly. Chronic untreated cases were compared with a similar group of canal cleaners 3 months after successful chemotherapy with Praziquantel administered at the start of the non-transmission season. All cases, except those previously treated, were egg positive at the time of blood sampling. Data from infected and treated cases were compared with measurements of serum immunoglobulin in a panel of European blood donors. The major findings are as follows: There is a consistently elevated total serum IgG concentration in infected groups which is accounted for mainly by an increased IgG1 subclass (greatest in chronic cases) and by a remarkable 10- to 11-fold increase in IgG4 in the untreated chronically infected group and in the schoolchildren. All infected groups showed high IgG antibody responses to all life cycle stage antigens, and IgM titres were high to adult and egg antigens in untreated canal cleaners. Major differences were evident in the distribution of IgG subclass antibodies between the infected groups: the response to larval and adult antigens is poor or absent in IgG1, IgG2 and IgG3 in untreated chronic infections but is high in IgG4, whereas in acute cases with hepatosplenomegaly and in school-children IgG1, IgG2 and IgG3 antibodies to larval antigens are in high titre but IgG4 and IgM responses to larvae are low or absent, the response in these isotypes being restricted in these cases to adult and egg antigens. Comparing the treated and untreated canal cleaners, although these are separate groups, the data suggest that Praziquantel reduces total serum IgA and IgM levels but has little effect on the raised IgG component except for the IgG4 subclass. The treated chronic cases show a reversal in the ratio of IgG1, IgG2 and IgG3 to IgG4 antibodies to larval and adult antigens compared with the untreated chronic group-the IgG4 response being low by 3 months after treatment and the IgG1, IgG2 and IgG3 being high. These data are discussed in relation to the possible importance of antibody isotype selection in determining host susceptibility to infection, with reference to age, exposure and treatment of the host.

Adolescent↗
PubMed1987

Antibody isotypes of immune complexes in schistosomiasis mansoni in Sudan.

From a panel of monoclonal antibodies to Schistosoma mansoni, one that is specific to a shared cercarial and schistosomular antigen, and does not react with other major parasite species including Fasciola hepatica, was selected for use as an antigen-capture layer in a sandwich ELISA for detection of specific circulating immune complexes in the blood of S. mansoni-infected subjects from Sudan. The test, which identifies immune complexes of only a single antibody-bound antigen, is developed using human Ig class- and IgG subclass-specific enzyme (HRP)-antibody conjugates. European blood donor sera and those with rheumatoid factor and/or anti-nuclear antibody are negative in this test. The prevalence and distribution of the different antibody isotypes in antigen-specific complexes was determined in 276 subjects of four infection groups; primary school children, adult irrigation canal cleaners with chronic infections, an equivalent group of Praziquantel cured canal cleaners, and hospital-referred cases with severe hepatosplenic symptoms. The isotype profiles of antibodies in the specific complexes were compared with those in the total serum complexes prepared by polyethylene glycol precipitation. In chronic infections and in children there is a high prevalence of IgG and IgM specific complexes, the IgG being predominantly IgG1, with little or no IgG3 and IgG4. Treated chronic infections show reduced specific complexes in all classes of antibody. Compared with chronic and children's infections, a large proportion of the patients with severe infections have in addition to high IgM, high levels of IgG2, IgG3 and IgG4 specific complexes, a fact which suggests a causal relationship between antibody production in one or more of these subclasses to the circulating antigen and symptoms of hepatosplenic disease. Although all subjects have significant amounts of total serum complexes with IgG, untreated chronic infections have much higher concentrations than other infected groups. This group also has the highest levels and prevalence of IgM and IgE complexes. In treated chronic cases IgG and IgM total complexes are greatly reduced. The significant finding in patients with severe symptoms is the relatively high IgA immune complex level compared with other groups. Taken overall the results suggest that screening of populations in endemic regions for serum immune complexes by specific and non-specific means could offer valuable data on the significance of antibody responses to circulating antigens in different isotypes in relation to pathogenesis.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1987

Three cases of partial trisomy 9q in one generation due to maternal reciprocal t(6;8;9) translocation.

A family is described in which three siblings had congenital abnormalities consistent with partial trisomy 9q syndrome. Karyotyping indicated that the mother was a carrier of two separate balanced reciprocal translocations involving three chromosomes (46,XX,t (6;8;9)(6q27;8p23;9q32;9q13] resulting from four breakpoints. The three siblings had inherited the der(8) from their mother and hence were partially trisomic for 9q32----9qter and partially monosomic for 8p23----8pter (46,XX,der(8),t(8;9)(p23;q32)mat). The clinical features of the three cases were comparable to those reported in the literature.

Chromosome Banding↗
PubMed1987

Elevated G gamma gene expression with specific beta S gene haplotype, normal gamma gene maps and presence of the Xmn I site -158 5' to the G gamma gene in Indian sickle cell anemia.

In nine Indian patients ranging in age between four and 61 years, with mild Hb SS disease and very high Hb F levels, the G gamma globin chain levels of their fetal hemoglobin ranged between 64.0% and 70.0%, with a mean of 68.1% (S.D. +/- 2.6) of the total amount of gamma-globin chains. Eight of the nine patients were homozygous for a specific beta S gene haplotype #31. The other one was doubly heterozygous for the same specific haplotype and another haplotype, which differed from haplotype #31 by the presence of Bam HI site 3' to the beta gene and absence of Pvu II site 5' to the psi beta gene. The gamma gene organization studied by Pst I restriction enzyme analysis was found to be normal and the Xmn I site -158 5' to G gamma gene was present in all patients examined.

Anemia, Sickle Cell↗
PubMed1986

Sickle cell anemia associated with alpha-thalassemia in Malaysian Indians.

The Indian rubber estate workers in Negri Sembilan, Malaysia, who originated from Orissa in India were found to have a high frequency of Hb S (Joishy SK, Hassan K: Clin Res 28:280, 1980). Unlike the usually severe clinical picture of sickle cell anemia seen in African and American blacks, the clinical picture of the disease in this population was mild and many have reached old age. We studied the leukocyte DNA of 12 patients with sickle cell anemia, ranging in age from 4 to 61 years and 30 sickle cell trait carriers, ranging in age from 7 to 63 years, for the presence of alpha-globin gene deletions by gene mapping according to Southern (Southern EM: J Mol Biol 98:503, 1975), using alpha- and zeta-globin gene probes obtained by nick translation of the alpha- and zeta-globin genes cloned into plasmid. All 12 sickle cell anemia patients were found to have alpha-thalassemia2 (alpha-thal2), either in the homozygous or heterozygous condition. Of the Hb S trait carriers, six did not have alpha-thal2 or alpha-thal1 and 24 had alpha-thal2 (15 heterozygous, 9 homozygous). Seven of these Hb S trait carriers with alpha-thal2 had an additional gene abnormality. Five of them had a fast-moving Eco RI fragment 5.6 kb long that hybridized with zeta-specific probe but not with alpha-specific probe. An unusual DNA pattern of a different type was further found in the other two. Bgl II restriction analysis showed that the alpha-thal2 was mostly of the rightward deletion alpha-thal1 genotype. None of the sickle cell anemia patients and Hb S trait carriers had deletion type alpha-thal1. The sickle cell anemia patients had very high levels of Hb F and low levels of Hb A2. The Hb S trait carriers with alpha-thal2 had relatively low levels of Hb S.

Adolescent↗
PubMed1986

Changes in human milk vitamin E and total lipids during the first twelve days of lactation.

Our previous study showed vitamin E deficiency in newborns (69.7%) and mothers at term (85.9%) when the ratio between serum vitamin E in mg/dl and total lipids in g/dl was used as an indicator of vitamin E status. This study was conducted to determine the human milk content of vitamin E. During the first 12 days of lactation milk vitamin E levels remained almost constant (day 1, 0.68 mg/dl; day 12, 0.65 mg/dl), milk total lipid levels increased daily (day 1, 1.11 g/dl; day 12, 3.60 g/dl), and the ratio between milk vitamin E and total lipids dropped steadily (day 1, 1.3; day 12, 0.2). In spite of this drop in vitamin E status, it is unlikely that vitamin E availability will be affected in neonates, because normal neonates absorb milk fats well and this ability increases with age.

Computers↗
PubMed1985

Gene mapping of Malaysian alpha thalassemias with alpha and zeta globin gene probes.

Restriction enzyme analysis of the alpha and zeta globin genes was carried out in four cases of Hb Bart's hydrops fetalis, in three patients with Hb H disease without Hb CoSp, in three patients with Hb H disease with Hb CoSp, in 47 individuals with alpha thalassemia trait, and in 47 normal individuals. All four cases of Hb Bart's hydrops fetalis resulted from deletions of alpha 1 and alpha 2 globin genes which did not extend to the psi zeta 1 and zeta 2 globin genes. The same type of deletion was observed in alpha thal1 carriers, but two newborns (one Malay and one of Chinese extraction) had a nondeletion type of alpha thal1 which was confirmed by quantitative alpha globin gene analysis. In addition, two other newborns diagnosed as alpha thal1 trait carriers (one Malay, one Chinese) were shown to have a deletion of both alpha globin genes by quantitative alpha globin gene analysis, but further testing with zeta globin gene probe failed to reveal an abnormal fragment length characteristic of an alpha globin gene deletion. We believe that this last condition is due to a large deletion which includes all alpha globin genes and all zeta globin genes on the same chromosome. On another front, Bgl II restriction analysis of all four Hb Bart's hydrops fetalis cases and the alpha thal1 trait carriers showed a 10.5-kb Bgl II restriction fragment, in the hydrops fetalis as a single band, while in the carriers this 10.5-kb fragment was accompanied by the usual normal 12.5-kb and 11.3-kb fragments. We report that this 10.5-kb fragment, previously thought to be specific for the Southeast Asian alpha thal1 gene deletion, is also common in normal individuals. Nevertheless, digestion with other enzymes can clearly differentiate the alpha thal1 and normal genotypes. We distinguish the findings in the alpha thalassemias from the extensive DNA polymorphism in the region of the alpha and zeta globin genes.

Chromosome Deletion↗