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Biomedical subjects

Z L Awdeh

Publications and source records attributed to Z L Awdeh.

At least 55 records · Page 3Linked to original sources
PubMed1981

Genetic analysis of C4 deficiency.

The inherited structural polymorphism in the fourth component of complement was studied in the family of a child with homozygous deficiency of this protein. It was shown that a number of family members, including the child's parents, carried a C4 haplotype, C4A*QO C4B*QO, that produced no detectable protein at either the Chido (C4B) or Rodgers (C4A) locus. The family contained individuals with one, two, three, or four expressed C4 genes, and the mean serum C4 levels in such individuals roughly reflected the number of structural genes.

Chromosome Mapping↗
PubMed1980

Inherited structural polymorphism of the fourth component of human complement.

Human fourth component of complement (C4) was found to be highly polymorphic by agarose gel electrophoresis of neuraminidase-treated plasma. The system allows clear-cut separation of the products of the two C4 genetic loci, C4A (acidic or Rodgers) and C4B (basic or Chido). There are at least six structural variants and a deletion allele at the C4A locus and two structural variants and a deletion allele at the C4B locus. Close linkage with no crossovers was found between the two C4 loci, allowing the definition of C4AB haplotypes, and between C4 haplotypes and the C2 and BF loci of the human histocompatibility complex. Nine C4 haplotypes, each with a frequency of 0.005 or more in Caucasians, were found. These studies provide direct evidence for two distinct but closely linked genetic loci for human C4 in the major histocompatibility complex on the short arm of chromosome 6.

Alleles↗
PubMed1977

Antibody response in marasmic children during recovery.

The I, II and III antibody responses to tetanus and diphtheria were assessed in marasmic and moderate protein-calorie malnourished children and compared to that of controls. The results suggest that during recovery marasmic children are capable of responding adequately to tetanus and diphtheria vaccines.

Antibodies, Bacterial↗
PubMed1976

Gel isoelectric focusing of human-serum transferrin.

Analysis of human serum transferrin on gel isoelectric focusing resolved this iron-transport protein into two iron-containing components which were identified by the use of radioactively labelled iron and iron-specific stain. These two components were found to be monoferric transferrin (Fe-transferrin) and diferric transferrin (Fe2-transferrin) with isoelectric points of 5.6 and 5.2 respectively. The estimation of the relative proportions of these two components in serum did not correspond to the calculated theoretical ratio based on random binding of iron to the two binding sites of transferrin. However, the analysis of partially resatured apotransferrin gave a ratio corresponding to a random distribution of iron. The significance of these results is discussed.

Apoproteins↗
PubMed1970

One cell-one immunoglobulin. Origin of limited heterogeneity of myeloma proteins.

Plasma-cell tumour 5563 forms a single molecular species of immunoglobulin IgG(2)a, i.e. one variant of heavy chain and one variant of light chain. The molecules formed are labile and undergo alterations in charge properties, which rapidly lead to heterogeneity of the myeloma protein after synthesis. The single immunoglobulin species originally formed is found only after the shortest time-intervals tested, i.e. 10min incubation. Two types of changes in charge properties take place: (1) The originally formed protein (component o) is converted via an intermediate o' into the most basic form of 5563 myeloma protein found in serum (component a). Charge differences between these components are suppressed at pH8.9, but can be studied by chromatography at pH6.5 or by analysis of isoelectric points by isoelectric focusing in polyacrylamide gel. The conversion of components o and o' into component a apparently commences soon after assembly of the molecules and proceeds to completion extracellularly. (2) The second type of charge difference that distinguishes components a, b, c and d is exhibited over the pH range 6.0-8.9, but not at acid pH, and has been studied by electrophoresis at pH8.9, by chromatography and by isoelectric focusing. Conversion of component a into components b, c, d and e is only partial so that all five components can be found at decreasing concentrations in serum. Both types of charge alteration can be effected in vitro in the presence of serum, with optimum pH8.0. None of the charge differences could be attributed to the secretion process, since a component with the same isoelectric point as component o was found in secreted myeloma protein (1h). We have found no evidence to support the idea that the first type of change from component o to component a is due to ring formation of N-terminal [(14)C]glutamine into pyrrolid-2-one-5-carboxylic acid; however, our findings do not exclude this process happening very rapidly to a precursor of component o, possibly the polypeptide chain during or immediately after synthesis. In studying this point we noted that not only the heavy chains but also the kappa-type light chain of mouse 5563 myeloma protein have a blocked N-terminus.

Amino Acids↗