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Biomedical subjects

R C Williams

Publications and source records attributed to R C Williams.

At least 451 records · Page 25Linked to original sources
PubMed1977

Use of polylysine for adsorption of nuclei acids and enzymes to electron microscope specimen films.

Enzymes and nucleic acids, both free and as bound in binary complexes, adsorb to electron microscope specimen films in well-distributed fashion if a dilute solution of polylysine is previously applied to the films. Electron micrographs are exhibited that demonstrate the usefulness of the technique in visualizing double- and single-stranded DNA, Escherichia coli RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) in negative stain, and polymerase complexed to poly(dA-dT) and to an 1100 base-pair restriction fragment of bacteriophage T7 DNA containing the early promoters. The base-pair spacing of DNA prepared for electron microscopy by the polylysine method was found to be 0.326 nm. Four promoter sites on the T7 fragment were located at 215, 440, 560, and 670 base-pair distances from the left terminus. When poly(dA-dT) was incubated with a 20-to-1 weight ratio of polymerase the bound enzyme particles were found to be about two-thirds as closely packed as is sterically permissible.

DNA↗
PubMed1977

Electron microscope studies of transient complexes formed between Escherichia coli RNA polymerase holoenzyme and T7 DNA.

Electron microscopy was used to study the formation of random complexes between Escherichia coli RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) and a promoterless fragment (Mbo I-C) of bacteriophage T7 DNA, and to determine the location of the polymerase molecules bound at 3 degrees to the promoter-containing (Hinf)1100 fragment of the same DNA. The value of the Ka of random binding is about 3 times 10(4)M-1 when the enzyme is slowly diluted from its storage condition and is incubated with DNA for up to 2 min at 37 degrees. If dilution is rapid and occurs in a single step, or if incubation extends beyond 5 min, a substantial portion of RNA polymerase is converted to a form that binds randomly with a much greater affinity (about 10(8)M-1). Hence true random binding by RNA polymerase holoenzyme is much weaker than previously thought. However, great caution is required in assessing the extent of random binding where damage to the enzyme may occur. When RNApolymerase holoenzyme is incubated at 0 degrees with promoter-containing fragment (Hinf)1100, complexes form at the same promoter sites utilized at 37 degrees, although the highly stable "open" promoter complex is not formed under these conditions. However, the extent of binding is reduced as compared to promoter complexes formed at 37 degrees. This gives direct evidence for formation of complexes with promoter sites that have properties of the hypothetical "closed"complexes formed between RNA polymerase and duplex DNA.

Coliphages↗
PubMed1977

Discrepancy between Clq deviation and Raji cell tests in detection of circulating immune complexes in patients with leprosy.

Samples of serum from 45 patients with different clinical forms of leprosy and from 17 patients with systemic lupus erythematosus were studied in parallel for circulating immune complexes with use of two different in vitro tests adjusted to the same degree of sensitivity. The Clq deviation test relied upon the reaction of the complement component Clq with immune complexes. The Raji cell test detected complement-fixed immune complexes that bound to the complement receptors on cultured, bone marrow-derived lymphocyte-like Raji cells. Thirty (67%) of 45 patients with leprosy showed immune complexes according to the Clq deviation test; however, only two (7%) of the 30 samples of sera with positive Clq test results were positive by the Raji cell test. In contrast, 54% of 13 samples of sera from patients with systemic lupus erythematosus positive by the Clq test were positive according to the Raji cell test. Since Clq is known to react with DNA as well as with bacterial antigens, the Clq reaction may in fact be detecting antigenemia in many instances. Considerable caution is warranted in application of sensitive screening tests for assay of circulating immune complexes in various states of infectious diseases.

Antibodies↗
PubMed1977

Immunologic function in humans before and after hyperthermia and chemotherapy for disseminated malignancy.

Multiple immunologic parameters were studied in three patients prior to and after hyperthermia treatment for disseminated malignancy. Two patients had malignant melanoma and received chemotherapy during the hyperthermia treatment. One had adenocarcinoma of the stomach and received no concomitant chemotherapy. Rapid rosettes as a measure of thymus-derived lymphocytes (T-lymphocytes) were found to increase significantly after therapy (P less than 0.05) both in percentage and absolute numbers. There was no change in the numbers or percentages of other markers for T-lymphocytes or bone marrow-derived B-lymphocytes. Complement profiles revealed a significant decrease in C3 (P less than 0.005) after hyperthermia but no change in levels of other components of the alternate pathway. Antibody-dependent lymphocyte-mediated cytotoxicity and polymorphonuclear cell-mediated antibody-dependent cytotoxicity were also depressed after hyperthermia. No change was observed in immunoglobulin levels with hyperthermia therapy. Results indicated that hyperthermia may favorably alter the immune balance between tumor and host in selected instances.

Adenocarcinoma↗
PubMed1977

Effects of pneumococcal mucopeptide and capsular polysaccharide on phagocytosis.

Pneumoccal cell wall and capsular products from eight serotypes were tested for their ability to inhibit polymorphonuclear neutrophil killing of the same eight pneumococcal strains. Crude pneumococcal cell wall preparations from all serotypes inhibited phagocytic killing of several pneumococcal serotypes, and were just as effective with heterologous as with homologous strains. Phagocytosis dependent on heat-labile serum factors was inhibited, whereas phagocytosis not dependent on heat-labile factors was not significantly affected. These findings were compatible with inhibition of complement consumption. The inhibitory activity was found in a purified cell wall mucopeptide, whereas purified capsular polysaccharides failed to inhibit phagocytosis.

Cell-Free System↗
PubMed1977

Effect of temperature on bacterial killing by serum and by polymorphonuclear leukocytes.

Bacterial killing by serum alone and by polymorphonuclear )PMN) leukocytes was studied at 37 degrees C and compared with killing at 39 and 41 degrees C. The test organisms for serum killing were Staphylococcus aureus 502A (serum resistant) and Escherichia coli O14 (serum sensitive). The organisms used in PMN killing tests were Streptococcus pneumoniae type 29 and E. coli O86.S aureus was not killed by serum alone at any temperature. Changes in temperature did not affect the rate of serum killing of E. coli O14 for the first 60 min, but by 90 and 120 min there was a discrepancy with continued killing at 37 degrees C, but no further killing at 39 and 41 degrees C. PMN phagocytic killing of the pneumococcus was enhanced at 39 degrees C compared with 37 degrees C, and phagocytic killing of E. coli O86 was decreased at 41 degrees C when compared with 37 degrees C. Therefore, it appears that under certain circumstances fever may aid the host PMNs in destroying organisms, whereas under other circumstances it may interfere with such destruction.

Blood Bactericidal Activity↗
PubMed1977

Classical and alternative complement pathway activation by pneumococci.

Sixty-two strains of Streptococcus pneumoniae were studied for their abilities to consume selected components of classical and alternative complement pathways in human sera. The classical pathway was blocked by chelating calcium with ethyleneglycol-bios (beta-aminoethyl ether)-N,N-tetraacetic acid and by removing C4. The alternative pathway was blocked by removing factor B. Each strain's activation of the two pathways was compared with its nonimmune reactivity with the Fc region of immunoglobulin G (IgG). Activation of the classical complement pathway appeared to be independent of such Fc reactivity. Highly Fc-reactive strains, however, were shown to activate the alternative pathway more effectively than did less Fc-reactive strains. Since pneumococcal activation of the alternative pathway requires non-immunospecific IgG, these findings suggest that nonimmune binding of IgG on the pneumococcal surface endows it with complement-activating properties.

Complement System Proteins↗
PubMed1977

Antibodies to human caudate nucleus neurons in Huntington's chorea.

Antibodies reacting with neuronal cytoplasmic antigens present in normal human caudate and subthalamic nuclei were detected in 37 of 80 probands afflicted with Huntington's disease (HD). IgG antibodies were detected by immunofluorescence using frozen sections of unfixed normal human and rat brain. Specificity of IgG binding was confirmed using pepsin F(ab')2 fragments of IgG isolated from positive sera. In vitro complement fixation of IgG antibody was detected in 22 of 31 sera tested. Neuronal cytoplasmic antigens reacting with positive HD sera were diminished after trypsin or RNAase treatment of tissue sections but were not removed by DNAase, neuraminidase, EDTA, or dithiothreitol treatment. Antibody staining of neurons could be removed after absorption with isolated caudate nucleus neurons or by using perchloroacetic acid extracts of caudate nucleus. Prevalence of antibody reacting with neuronal cytoplasm was 3% in 60 normal controls and 6% among a wide variety of patients with diverse neurological disorders. However, one-third of 33 patients with Parkinson's disease showed presence of antineuronal antibody. Among patients with HD, a significant association was noted between duration of clinical disease greater than 7 yr and titers of antibody of 1:2 or greater (P less than 0.001). When 115 family members of HD probands were tested, 30% of unaffected spouses showed presence of antineuronal antibody. 23.2% of first-degree relatives at risk for developing HD was also positive (P less than 0.001). 10.5% of second-degree relatives showed presence of antineuronal antibody. These data may support an environmental or infectious factor somehow involved in the ultimate expression of HD.

Adult↗
PubMed1977

Lymphocyte surface markers in acute rheumatic fever and post-streptococcal acute glomerulonephritis.

Lymphocyte cell-surface markers were examined in forty children with acute rheumatic fever (ARF) and twelve with acute post-streptococal glomerulonephritis (AGN) and compared to thirty-six normal controls of similar age. Cell-surface-marker studies included surface Ig using fluorescein-labelled F(ab)2 anti-F(AB')2, IgG aggregate binding cells, and EAC rosettes. T cells were identified both as 'active' rosettes and total E-binding cells. Proportions and absolute numbers of cells bearing surface Ig and Fc receptors were elevated in subjects with AGN (Pless than0-01-0-5), whereas proportions of cells producing EAC rosettes were diminished. Patients with acute rheumatic carditis or chorea showed a substantial elevation in proportions and numbers of active T-cell rosettes (Pless than0-01). Streptococcal antigen binding cells capable of forming rosettes with autologous cells coated with group A streptococcal membranes were elevated in the acute phase of both rheumatic fever and acute glomerulonephritis(Pless than0-01). The majority of such cells were removed by passage over insolubilized Ig-anti-IgG columns and appeared to be B cells.

Acute Disease↗
PubMed1977

Lymphocytotoxic antibodies in patients with inflammatory bowel disease and their spouses--evidence for a transmissible agent.

Serum lymphocytotoxic antibodies (LCA) were detected in twenty-seven out of fifty-three (51%) patients with inflammatory bowel disease (IBD) and in twenty-three out of their fifty-three (43%) unaffected spouses. The prevalence of LCA in both groups was significantly increased (P less than 0.001) compared to that in age- and sex-matched controls (11%) or in control spouses (6%). Concordant expression of LCA occurred in sixteen out of the fifty-three (30%) patient-spouse pairs compared to only one out of the fifty-three (2%) control-spouse pairs (P less than 0.001). In contrast to the LCA results, heterophile antibody titres were similarly distributed in all four study groups. It is suggested that LCA may represent markers of infectious agents in IBD and that their occurrence in unaffected close contacts of patients may indicate transmission of such agents to these subjects.

Antibodies↗
PubMed1976

Suppression of leukocyte chemotaxis by human IgA myeloma components.

Sera from patients with IgA myeloma suppressed polymorphonuclear leukocyte (PMN) chemotaxis, while generally little or no suppression was observed with sera from patients with IgG myeloma or Waldenstrom's macroglobulinemia. Chemotactic inhibitory activity was not limited to a single chemotactic factor and was equivalent when C5a, bacterial factor, casein, or normal serum were used as chemotactic attractants. No association was noted between the degree of inhibitory activity and the IgA subclass or light chain type. Chemotactic inhibitory activity was found to be directly associated with isolated IgA M components, and similar chemotactic suppression was noted with purified preparations of normal human colostral IgA. By comparison, IgA preparations were most effective in suppressing PMN chemotaxis and had a much lesser effect on monocyte chemotaxis. The mode of IgA chemotactic inhibition was cellular and at least partially reversible after a 37degreesC incubation in the absence of IgA. Some inhibition of PMN random mobility was noted with certain IgA preparations, although such effects did not parallel the degree of chemotactic inhibition. Fractionation of IgA myeloma sera and IgA M components by sucrose density gradient centrifugation showed multiple peaks of inhibitory activity in 10 to 13S fractions. The majority of IgA inhibitory activity was lost after pepsin digestion or sulfhydryl reduction and alkylation of isolated M components. When isolated IgA M components were fractionated on Sephadex G-200, inhibitory activity was associated with the exclusion volume and was abolished by reduction and alkylation procedures which resulted in a conversion of polymeric IgA to monomeric IgA.

Caseins↗
PubMed1976

Antibodies reacting with cytoplasm of subthalamic and caudate nuclei neurons in chorea and acute rheumatic fever.

46% of sera from 30 children with rheumatic chorea showed IgG antibody reacting with neuronal cytoplasm of human caudate and subthalamic nuclei. The antibody was also detected in 14% of 50 children with active rheumatic carditis. 55 normal control sera, as well as 148 sera from a broad variety of other disease states showed a low prevalence (1.8-4.0%) of positive reactions. In rheumatic chorea the presence of anti-neuronal antibody appeared to correlate with severity and duration of clinical attacks. Antibody reacting with neuronal cytoplasm was completely removed by absorption with Group A streptococcal membranes or with isolated human neurons from caudate nucleus. Partial absorption of antibody was also recorded using Group A cell wall preparations but not with Group A carbohydrate. No absorption of positive reactions was seen with streptococcal Group D membranes or cell walls. In rheumatic chorea, anti-neuronal antibody appeared to represent cross-reaction with antigens shared by Group A streptococcal membranes.

Acute Disease↗
PubMed1976

Carbamoylated hemoglobins A and S: physical properties.

Dimer-tetramer association constants (K2,4) of derivatives of CO-hemoglobins A and S specifically carbamoylated at the NH2-terminal valine residues were measured. Reactivites of the beta-93 sulfhydryls of the hemoglobin A derivatives were also investigated. As compared with the association constants of the parent molecules, the values of K2,4 of both hemoglobin types are raised by carbamoylation of the alpha-chain NH2 terminus, lowered by carbamoylation of the beta-chain NH2 terminus, and raised by carbamoylation of both termini. The apparent second-order rate constant for reaction of p-mercuribenzoate (PMB) with the beta-93 sulfhydryls is, however, unchanged by carbamoylation. These two observations are interpreted to indicate that in the liganded molecule structural changes are produced at the interface between dimers but not in the region of the beta-93 sulfhydryls. From the combination of the K2,4 measurements with ligand-binding data for the same derivatives (Kilmartin, J. V., et al. (1973), J. Biol. Chem. 248, 4039; Nigen, A. M., et al. (1974), J. Biol. Chem. 249, 6611) the carbamoylation-induced changes in the dimer-tetramer association constants of the unliganded derivatives were estimated to be of magnitude equal to or smaller than those in K2,4. It is concluded that much of the change in oxygen affinity that occurs upon carbamoylation of hemoglobins A and S can be accounted for without invoking extensive structural changes in the unliganded molecule.

Binding Sites↗
PubMed1976

Preschool detection of asymptomatic bacteriuria: a public health program.

A total of 95% of parents registering their children for kindergarten agreed to screening for urinary tract infection (UTI) in their children. Urine specimens from 1591 children (87%), obtained at the school or at home, were tested. Only minor problems were encountered when parents prepared the specimens at home and mailed them to the laboratory for reading; the proportion of false-positive results was higher in these samples. If screening for UTI becomes established, it appears worth while to conduct this at the time of registration for kindergarten, either in the school by lay persons or in the home by parents.

Bacteriuria↗