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K M Williams

Publications and source records attributed to K M Williams.

At least 109 records · Page 6Linked to original sources
PubMed1990

Demonstration of cross-reactivity between bacterial antigens and class I human leukocyte antigens by using monoclonal antibodies to Shigella flexneri.

Bacterial envelope proteins which share immunodeterminants with the human leukocyte antigen (HLA) class I histocompatibility antigen HLA-B27 may invoke spondyloarthritic disease through the process of molecular mimicry in patients expressing this phenotype. Monoclonal antibodies generated by the immunization of BALB/c mice with envelope proteins of Shigella flexneri type 2a were tested for reactivity against cultured lymphoblastoid cell lines of defined HLA phenotype. As measured by flow microfluorometry, four immunoglobulin M monoclonal antibodies reacted preferentially with HLA-B27-positive lymphocytes (HOM-2, MM) as compared with a B27-loss mutant line (1065) or cells lacking major histocompatibility complex class I antigen (Daudi, K562). Monoclonal antibodies also reacted with mouse EL-4 cells transfected with and expressing the HLA-B7 gene. Western immunoblot analysis of isolated enterobacterial envelopes demonstrated that the reactive epitope was present on bacterial proteins with an apparent relative molecular mass of 36 and 19 kilodaltons. The structural basis for the cross-reactivity of bacterial antigen and HLA-B27 appeared to reside in the portion of the HLA molecule that is responsible for allotypic specificity (amino acids 63 through 83), since monoclonal antibodies were positive by enzyme-linked immunosorbent assay with synthetic polypeptides corresponding to this segment.

Amino Acid Sequence↗
PubMed1990

Dichotic perception and memory following electroconvulsive treatment for depression.

Verbal and visuospatial memory and dichotic listening performance were examined in 15 acutely depressed patients with no history of ECT, 17 depressed patients currently in remission, 15 remitted depressed patients who had received ECT six months or more in the past, and 20 normal controls. The neuropsychological functioning of an additional group of 10 acutely depressed patients was also studied before and two weeks after ECT. The results revealed some evidence of logical and autobiographical memory impairment two weeks following ECT, but no evidence that ECT impaired dichotic listening ability. Rather, a normalisation of hemispheric laterality was apparent on the dichotic listening task following ECT and the concomitant relief from depression. There was also no evidence of cognitive dysfunction on any task in individuals who were tested six months or more following their last ECT treatment.

Adult↗
PubMed1990

Demonstration of shared epitopes between bacterial proteins and HLA class-I proteins using monoclonal antibodies.

Monoclonal antibodies were used to identify the presence of epitopes on bacterial proteins which are cross-reactive with HLA-B27. Anti-HLA-B27 monoclonals, B27M2 and YE-2 reacted with a major protein of approximately 35 kDa, which was found to be OMPA. On some strains a 19 KDa protein was also seen. Anti-Shigella flexneri monoclonals were also developed which reacted with a 36 kDa protein and a 19 kDa protein. The 36 kDa protein was OMPF. These antibodies also reacted with a synthetic peptide representing amino acids 63-83 of the B*2705 sequence. These results support a potential role for molecular mimicry in the spondyloarthropathies.

Antibodies, Monoclonal↗
PubMed1990

heterogeneity of creatine kinase isoenzyme MM in serum in myocardial infarction: interconversion of the "normal" and "abnormal" sub-bands by glutathione.

We used isoelectric focusing (IEF) in polyacrylamide gels to investigate the effects of glutathione on the sub-bands of serum creatine kinase (CK; EC 2.7.3.2) isoenzyme MM in acute myocardial infarction. The intensity of the "abnormal" sub-bands c (pI 7.25), e (pI 6.85), and g (pI 6.50) increased, and that of the "normal" sub-bands 1 (pI 6.91), 2 (pI 6.65), and 3 (pI 6.35) decreased, following serum incubation with reduced glutathione (GSH, final concentration 1.25 mmol/L). Further incubation with oxidized glutathione (GSSG, final concentration 5 mmol/L) reversed this change and restored the original pattern, whereas GSSG at 7.5 mmol/L caused sub-bands c, e, and g to disappear and sub-bands 1, 2, and 3 to be enhanced. Sequential incubation of serum with 2.5 mmol of GSSG and 7.5 mmol of GSH per liter produced the opposite sequence of events; i.e., the "abnormal" sub-bands disappeared then reappeared (and GSH at 10 mmol/L enhanced their reappearance). At higher concentrations, glutathione (GSH or GSSG) impaired the detection of the CK-MM sub-bands after IEF, an effect that was "quenched" by heat-inactivated serum of low CK activity. Likewise, the intensity of tissue CK-MM (corresponding to myocardium extracted into 100 mmol/L Tris HCl buffer, pH 7.4) was greatly enhanced by adding heat-inactivated serum to the tissue extract before IEF. We discuss the significance of these findings for the diagnosis of myocardial infarction.

Creatine Kinase↗
PubMed1989

Chiral inversion of 2-arylpropionic acid non-steroidal anti-inflammatory drugs--1. In vitro studies of ibuprofen and flurbiprofen.

The mechanism of inversion of the enantiomers of 2-arylpropionic acids was investigated in vitro using tissue homogenates. Crude rat liver homogenate was shown to mediate the inversion of R to S-ibuprofen, but not inversion of the S to the R-enantiomer. Inversion required CoA and ATP as cofactors. In contrast, R-ibuprofen was not inverted by homogenates of kidney or small intestine and there was no inversion of the enantiomers of flurbiprofen by any of these tissue homogenates. Long-chain acyl-CoA synthetase was partially purified from rat liver microsomes and bound to Matrex Gel Red A. R-Ibuprofen was shown to be a substrate for this enzyme while S-ibuprofen and R and S-flurbiprofen were not substrates. These data are consistent with the hypothesis that the stereospecificity of inversion is controlled by the acyl-CoA synthetase. R-Ibuprofen-CoA did not racemize in either buffer solution (pH 7.4) or human plasma consistent with the hypothesis that racemization of the CoA thioesters is mediated enzymatically.

Animals↗
PubMed1989

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis without a stacking gel: use for high sample throughput.

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis without a stacking gel minimizes lateral spreading of protein when samples are applied in agarose wells and allows high sample throughput (6 samples/cm gel width). The method is simple and convenient to use and gives comparable resolution to the standard method with 4-20% or 6-30% polyacrylamide gradient gels. Best results are obtained when the upper zone of the separating gel is of low polyacrylamide concentration. This indicates a need for the molten agarose to penetrate and anneal with the separating gel.

Electrophoresis, Polyacrylamide Gel↗
PubMed1989

Electrophoresis of human salivary proteins: response to natural stimulation.

Human saliva was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the response to different natural stimuli investigated. Serva Blue R revealed pink/violet-staining proteins ("lumicarmines"). These intensified following stimulation but in an unpredictable and sometimes disproportionate manner, causing pattern changes. This variable response undermines their potential forensic value for suspect identification.

Eating↗
PubMed1989

Synthetic oligonucleotide probes complementary to the HLA-B variable region hybridize with Klebsiella pneumoniae.

Three oligonucleotide probes complementary to base sequences of the HLA-B variable region were used to probe clinical and foodborne isolates of Klebsiella spp. by DNA colony hybridization. One oligonucleotide (RR-3) corresponding to amino acid residues 66-74 of the HLA-B27.1 sequence and one corresponding to residues 66-74 of the HLA-B7 sequence (RR-5) hybridized with K. pneumoniae under conditions of high stringency. A genomic library was constructed using K. pneumoniae K43 chromosomal DNA, and a 1 kb PstI restriction fragment was found to contain the sequence associated with specific binding of the oligonucleotide probes. After purification and radiolabeling, the cloned fragment hybridized with 96.2% of the K. pneumoniae isolates by DNA colony hybridization. These results confirm the presence of sequence similarities between bacterial DNA and the MHC Class I variable region.

Antigens, Bacterial↗
PubMed1989

Chirality: pharmacokinetics and pharmacodynamics in 3 dimensions.

1. Biological macromolecules are able to distinguish between enantiomeric substrates. A three-point interaction between the drug enantiomers and the macromolecule (Easson-Stedman hypothesis) can frequently account for this selectivity. 2. Significant pharmacodynamic differences between enantiomers are more the rule than the exception. 3. Pharmacokinetic differences between enantiomers are, in general, not as great as the pharmacodynamic differences. However, stereoselective protein binding, metabolism and renal clearance are still very important aspects of understanding drug disposition and the time course of drug action. 4. There may be pharmacokinetic and pharmacodynamic enantiomer-enantiomer interactions. Consequently, the activity and disposition of a racemic drug may not be the simple sum of the activities and disposition of the individual enantiomers. 5. Enantiomers have been used as sensitive 3-dimensional probes to establish structure-activity relationships, to provide insights into genetic polymorphism of drug metabolism, and to provide insights into other aspects of drug disposition. 6. A need for a 3-dimensional understanding of pharmacodynamics and pharmacokinetics is implicit in the asymmetric nature of biological environments.

Animals↗
PubMed1989

Heterogeneity of serum creatine kinase isoenzyme MM in myocardial infarction: clinical significance and post-synthetic conversion of "abnormal" sub-bands.

We investigated the "abnormal" sub-bands of serum creatine kinase (CK; EC 2.7.3.2) isoenzyme MM in acute myocardial infarction (AMI), using isoelectric focusing in polyacrylamide gels, and compared the patterns with those for non-AMI patients and for athletes with increased CK. The "abnormal" sub-bands a (pI 7.55), b (pI 7.35), c (pI 7.25), d (pI 7.05), e (pI 6.85), f (pI 6.72), g (pI 6.50), h (pI 6.40), i (pI 6.28), j (pI 6.20), and k (pI 6.15), in common with "normal" sub-bands 1 (pI 6.91), 2 (pI 6.65), and 3 (pI 6.35), were less uniformly distributed in the AMI and demonstrated a faster rate of anodal conversion than in the non-AMI patients and athletes. "Abnormal" sub-bands a and b were detected only in the AMI patients. Incubation of myocardial CK-MM, predominantly CK-MM 1, with 2-mercaptoethanol, 15 mmol/L, resulted in conversion to the "abnormal" sub-bands b and c. Incubation of myocardial CK-MM with normal serum of low total CK yielded CK-MM 3, which on further incubation with 2-mercaptoethanol, 15 mmol/L, resulted in conversion to the "abnormal" sub-bands f and g. Comparable in vitro incubation of serum from AMI patients gave pattern changes consistent with conversion of CK-MM 1 to b, c; CK-MM 2 to d, e; and CK-MM 3 to f, g.

Adult↗
PubMed1988

Reaction of anti-HLA-B monoclonal antibodies with envelope proteins of Shigella species. Evidence for molecular mimicry in the spondyloarthropathies.

Immunologic cross-reactivity between enteric bacteria and the HLA-B27 protein may play a role in the etiology of Reiter's syndrome and reactive arthritis. The reactivity of two anti-B27 mAb (B27M1 and B27M2) with envelope proteins of Shigella flexneri isolated from Reiter's syndrome patients was studied by Western blot analysis. Proteins with an apparent Mr of approximately 36 and 23 kDa reacted with both mAb in ascites. mAb against related HLA class I Ag B7 and B40 did not react with the 23 kDa protein. Relatively high concentrations of antibody were required for reactivity, suggesting a low affinity interaction. Additional evidence for cross-reactive epitopes was obtained by ELISA against whole envelope and by using unsolubilized envelope to inhibit binding of M1 and M2 to B27-positive cell lines, as measured by quantitative flow microfluorimetry. The presence of cross-reactive proteins was not related to the presence of the intact virulence-associated plasmid or the invasive phenotype. Two Shigella sonnei isolates not implicated as causative agents of Reiter's syndrome or reactive arthritis showed a similar pattern of cross-reactivity. These results indicate that cross-reactive epitopes may be present on "arthritogenic" bacteria, but their presence is not a unique feature of such strains and is not the sole factor in induction of arthritis in B27-positive individuals.

Animals↗
PubMed1988

High resolution two-dimensional electrophoresis and sodium dodecyl sulphate-polyacrylamide gel electrophoresis of cheese proteins after rapid solubilisation.

The proteins of cheese are rapidly solubilised by heating to 95 degrees C in buffered 2% sodium dodecyl sulfate, 5% 2-mercaptoethanol. Electrophoretic analysis of the solubilised proteins by either one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis or high resolution two-dimensional electrophoresis yields reproducible patterns characteristic of an individual cheese and its extent of ripening. The patterns reveal (i) the residual amounts of milk casein and whey proteins, and (ii) the appearance of casein degradation products, including pink-violet components as detected by Coomassie Blue staining.

Cheese↗
PubMed1988

An evaluation of two-dimensional electrophoresis for detection of human serum proteins in acute myocardial infarction.

High resolution two-dimensional electrophoresis indicates that serum proteins previously only detected in patients with acute myocardial infarction (AMI) (Gomo et al., Electrophoresis 1983, 4, 298-302) are also present in the serum protein patterns of other patients (AMI negative or demonstrating acute phase response) and are faintly detected even in controls. Thus, these proteins are not specific to AMI and are probably acute phase reactants. However, they do demonstrate a characteristic time course response in sequential samples from AMI patients.

Acute-Phase Reaction↗
PubMed1988

Stereoselective disposition of ibuprofen enantiomers in synovial fluid.

The simultaneous disposition of the enantiomers of ibuprofen in synovial fluid and plasma was studied in eight patients with arthritis. Concentrations of the active S-enantiomer in synovial fluid exceeded those of the R-enantiomer at all times in all patients with the ratio of S to R concentrations being 2.1 +/- 0.3 (mean +/- SE). Synovial fluid concentrations fluctuated much less than in plasma and exceeded plasma concentrations from 5.4 +/- 0.3 hours for R-ibuprofen and 5.5 +/- 0.6 hours for S-ibuprofen. Pharmacokinetic analysis suggested that, although the enantiomers diffuse into synovial fluid primarily in the unbound form, there may be significant diffusion of the enantiomers out of synovial fluid in the protein-bound form in some patients. Interpatient differences in the disposition of the enantiomers of ibuprofen in synovial fluid were evident and may contribute to the interindividual variability in response to treatment with ibuprofen.

Female↗