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R Ali

Publications and source records attributed to R Ali.

At least 91 records · Page 5Linked to original sources
PubMed1996

Probing structure-activity relationship in diamine oxidase--reactivities of lysine and arginine residues.

Lysine and arginine residues of pig kidney diamine oxidase (DAO) were modified with 2,4,6-trinitrobenzenesulphonic acid (TNBS), 2,3-butanedione and phenylglyoxal, respectively, using different concentrations and time periods. Lysine residues are classified into 3 categories: completely exposed, highly reactive; sluggish, partly buried; and unreactive, completely buried. About 21 lysine residues whose modification did not lead to any significant conformational change as well as loss of catalytic activity are believed to be less important for the structural stability of the enzyme. On the other hand, the remaining 19 lysine residues are more important in maintaining the native structure of the enzyme as evidenced by the change in hydrodynamic parameters and loss of catalytic activity upon their modification. Arginine residues when probed with butanedione or phenylglyoxal treatment resulted in the significant loss of catalytic activity without any change in conformation implicating their involvement in the catalytic function of the enzyme. Significant change in conformation was noted when 10 arginine residues were modified, which suggests the structural role of these residues.

Amine Oxidase (Copper-Containing)↗
PubMed1996

Nucleic acid-8-methoxypsoralen crosslinks bind monoclonal anti-Z-DNA antibody.

Native calf thymus DNA and poly(dA-dT).poly(dA-dT) were photo-adducted with 8-methoxypsoralen and characterized by thermal denaturation (Tm) and hydroxyapatite column chromatography. The data demonstrated the formation of interstrand photo-crosslinks. It has been shown by competition ELISA and band shift assays that crosslinked species of DNA-8-MOP and poly(dA-dT)-8-MOP photoadducts recognize previously defined monoclonal anti-Z-DNA antibody (Z22). The results indicate the possible presence of Z- or Z-like epitopes on nucleic acid-8-MOP crosslinks as Z22 antibody does not recognize other nucleic acid conformations. These studies also point out that conformational changes in DNA arising from the photo-addition could induce antibodies to DNA or could cause autoimmune disease.

Animals↗
PubMed1996

Antigen binding specificity of antibodies against 8-methoxypsoralen photoadducted DNA.

The photoadduct between native DNA and 8-methoxypsoralen was characterized on the basis of UV and fluorescence characteristics, Tm, nuclease S 1 digestibility and hydroxyapatite column chromatography. Approximately 80% of photoadduct has at least one diadduct (crosslink) per DNA molecule and only thymine was modified to the extent of 69%. The photo-crosslink was highly immunogenic inducing antibodies having apparent association constant of 1.3 x 10(-9)M. The immune IgG was highly specific towards nucleic acid-furocoumarin crosslink site without appreciable recognition of B-conformation or nucleic acid bases. The antibodies could be used as probe to detect and quantitate nucleic acid modified with furocoumarins in health and disease.

Antibodies, Antinuclear↗
PubMed1996

Multiple myeloma in the region of Bursa, Turkey: a retrospective analysis.

We evaluated the clinical and laboratory features of multiple myeloma in our patients and reviewed the factors that affected their survival. The study included 36 patients (12 women and 24 men) with multiple myeloma whom we followed up until death between October 1978 and June 1995. The age range was 34 to 75 years (mean age, 53.9). The chief complaints on admission were lumbar pain and pain in the extremities (77.8%) and generalized weakness (61.1%). The most common laboratory findings were severe anemia (hemoglobin < 8.0 g/dl) (50%), elevated erythrocyte sedimentation rate (75%), monoclonal spike in the serum protein electrophoresis (44.4%), and lytic skull lesions (72.2%). Twenty-three (64%) patients had a monoclonal IgG, 9 (25%) had IgA, 1 had IgD, 2 had light chain disease, and 1 was nonsecretory. Localized plasmacytoma was detected in 4 patients and 4 patients had amyloidosis in rectal and gingival biopsies. According to the Durie-Salmon staging system, 2 patients were in stage 1, 8 were in stage 2, and 26 were in stage 3. The mean survival was 31.4 +/- 4.3 months (range: 1 to 96). The 5-year survival rate was 11%. Sex, age at diagnosis, stage of the disease, hemoglobin level, platelet count, level of serum calcium, creatinine, serum paraprotein, and type of paraproteinemia were tested as prognostic parameters. We could not establish a statistically meaningful effect of these parameters on survival time. The first and second most common causes of death were renal failure and infection, respectively.

Adult↗
PubMed1995

Polyamine induced Z-conformation of native calf thymus DNA.

Conformational isomerization of native calf thymus DNA under the influence of spermine, spermidine and putrescine was monitored by UV absorption and immunospecific anti-Z-DNA antibodies. Immunological data indicated increased binding of anti-Z-DNA antibodies to polyamine-perturbed conformations of native DNA and double stranded poly(dG-dC). In the absence of polyamines, anti-Z-DNA antibodies did not bind to either polymers. Analysis of UV absorption studies indicates a left handed conformation of nDNA in the presence of polyamines. Moreover, we observed total aggregation of DNA in the presence of spermine on prolongued incubation. These perturbations in conformation were dependent on polyamine concentration. The results clearly suggest that certain regions of nDNA are sensitive to elevated levels of polyamines and are capable of undergoing B-->Z transition.

Animals↗
PubMed1995

HIV infection among injecting drug users in the South Australian methadone program.

OBJECTIVE: To investigate risk factors for infection with HIV among injecting drug users (IDUs) in South Australia. DESIGN: Retrospective case-control study comparing HIV-infected and uninfected IDUs who had received methadone at any time between January 1981 and June 1991. RESULTS: Most HIV-infected clients were diagnosed between 1985 and 1987. Men were more likely to be infected than women. A history of imprisonment was associated with a higher risk of infection on univariate but not multivariate analysis. Infected IDUs on average were three years younger than noninfected IDUs when they first injected drugs. CONCLUSIONS: Prevention programs should target young drug injectors. Prisons are important places to institute prevention programs.

Adult↗
PubMed1995

Native DNA fragments photocrosslinked to psoralen binds to anti-B and anti-Z DNA antibodies.

Calf thymus DNA fragments of varying size (100-600 bp) were covalently linked to psoralen in the presence of 365 nm UV light. The crosslinked species were separated from the monoadducts by hydroxyapatite column chromatography. The DNA-psoralen crosslink showed binding with naturally occurring anti-DNA autoantibodies. This was substantiated by the recognition of affinity purified IgG by DNA-psoralen crosslinks of varying DNA size. The photo-crosslinks exhibited considerable recognition of both monoclonal and polyclonal anti-Z-DNA antibodies in inhibition ELISA and band shift assay.

Animals↗
PubMed1995

Formation of thymine-lysine and cytosine-lysine adducts in DNA-lysine photoconjugate.

Lysine was covalently conjugated to calf thymus DNA by irradiation with UV light (wavelength, 253.7 nm). The results showed monofunctional covalent photobinding of lysine molecules with bases in DNA. Only the epsilon-amino group of lysine participated in the photoconjugation reaction. Thymine and cytosine were modified by 60% and 25% respectively. The kinetics of the DNA-lysine photoreaction showed that one lysine molecule was in the photobound state per 10, 6, 5 and 4 nucleotide base pairs of DNA on irradiation for 20, 30 40 and 60 min respectively.

Animals↗
PubMed1995

A sensitive novel staining agent for the resolved proteins on PAGE.

A more sensitive, stable and fast-reacting dye was isolated from the bark of Ratanjot by a simple solvent extraction procedure at high pH. The dye produced sharp, clear distinct stable bands of known proteins when resolved on polyacrylamide gel electrophoresis (PAGE) using sodium dodesyl sulfate (SDS), showing a rapid and strong affinity with protein molecules. Not only did proteins from peanut, separately stained with the new dye and Coomassie Brilliant Blue R-250, produce rapid comparable results, but also the protein bands were easily visualized and were less diffusible with clearer boundaries in the case of the new staining agent.

Coloring Agents↗
PubMed1995

Antigenic specificity of anti-ROS DNA antibodies: involvement of lysyl residues in antigen binding.

The antigenicity of native DNA modified with reactive oxygen species was examined. Goats were immunized with the modified polymer and the antibody response was estimated by direct binding and competition ELISA. The induced antibodies bound ROS-DNA and showed considerable binding to native DNA as well. Specificity analysis of the purified antibodies revealed the recognition of native B-, A- and allied conformations presented by various synthetic polynucleotides. The contribution of lysine residues to the immunochemical binding of purified IgG was investigated by modifying the free amino groups of lysine residues. The modification of lysine residues paralleled loss in IgG binding to ROS-DNA to the extent of 50%, suggesting that such residues might be involved in the antigen binding site of immunoglobulin molecule.

Acylation↗
PubMed1994

Linkage mapping around the ragged (Ra) and wasted (wst) loci on distal mouse chromosome 2.

Mice that are heterozygous for the ragged (Ra) mutation, which is semidominant, have ragged coats caused by an absence of certain hair types. Ra/Ra homozygous mice usually die soon after birth, are naked, and have edema. Mice that are homozygous for the recessive mutation wasted (wst) appear normal until soon after weaning, but then develop tremors and ataxia, undergo atrophy of the thymus and spleen, and die by around 28 days of age. The Ra and wst loci map to distal mouse chromosome 2, but have never been positioned with respect to molecular markers. We have now mapped each of these genes in interspecific backcrosses that were also typed for available molecular markers. The results show that Ra maps very close to D2Mit74 and Acra-4, with no recombinants in 165 mice, whereas wst maps 3 cM distal to the most telomeric molecular marker on mouse chromosome 2, Acra-4.

Animals↗
PubMed1994

Evaluation of a transgenic mouse model for alpha-1-antitrypsin (AAT) related liver disease.

We have attempted to produce a transgenic mouse model of the neonatal liver disease associated with the human PIZ allele. Analysis of a number of transgenic mouse lines carrying either a normal human PIM gene construct or the mutant Z is reported. Using isoelectric focusing analysis of plasma from transgenic mice, we have shown that the human AAT proteins produced in mice are processed in a similar way to their counterparts in humans. By comparing the level of M and Z mRNA in liver with the levels of M and Z proteins in plasma we have inferred that, as in humans, the mutant protein tends to accumulate within the hepatocyte. Accumulation of Z protein has also been demonstrated by immunocytochemistry. Two of the M transgenic lines produce such high levels of the human protein that it, like the Z protein, accumulates as globules. Histological features of livers from 116 mice of different ages and genotypes were examined: 37 non-transgenic, 62 Z transgenic (23 low expressing and 39 high expressing) and 17 M transgenic mice, all high expressing. Cirrhosis or fibrosis was not seen in any animal and we were unable to find any evidence for neonatal liver disease. Some necrosis was seen in all genotypes and this increased significantly with age with one Z line showing significantly more frequent necrosis than any other group. This line, the highest expressing Z line, was back crossed onto 7 different genetic backgrounds but no major differences between the back crosses with respect to liver disease were observed. The mouse model we have developed is compared with other transgenic Z mouse models; none of these is representative of human neonatal liver disease. Our view is that the transgenic animals generated in these experiments may be most useful for investigating the liver manifestations that almost invariably occur in ZZ adults. Alteration of additional factors other than accumulation of Z protein, for example inactivation of the endogenous mouse genes or some environmental challenge, might produce a mouse model with more relevance to neonatal liver disease.

Animals↗