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S Berman

Publications and source records attributed to S Berman.

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

C-reactive protein is involved in natural killer cell-mediated lysis but does not mediate effector-target cell recognition.

Anti-CRP and complement treatment of human peripheral blood lymphocytes significantly reduces natural killer (NK) cell-mediated cytotoxicity to K562 target cells as well as to MOLT-4 target cells. Although not all activity is eliminated by treatment of effector cells with antibody and complement, the reduction of NK function indicates that C-reactive protein (CRP) is present on a significant proportion of NK cells. Higher concentrations of anti-CRP or anti-CRP F(ab')2 fragments also reduce NK function; this suggests that CRP is not only present on these effector cells but may also play a role in NK-mediated killing. We initially suspected that CRP-ligand interactions might be involved in effector-target cell recognition. Several lines of evidence suggest that this is not the case. While F(ab')2 anti-CRP will block NK function, Fab anti-CRP will not, suggesting that the NK response is not impaired when surface CRP (S-CRP) is blocked but is only inhibited when the S-CRP is cross-linked and modulated. Neither CRP-C polysaccharide complexes (CRP-CPS) nor concentrations of CPS ranging from 0.1 microgram/ml to 200 micrograms/ml have any effect on NK cell-mediated killing. Treatment of target cells with a ligand for CRP or CRP prior to co-culture with NK effectors does not augment NK function. Single cell assays clearly demonstrate that high concentrations of anti-CRP have no effect on the formation of effector-target cell conjugates. Although these concentrations of anti-CRP do not block effector-target cell conjugation in the single cell assay, they do block the killing of conjugated target cells. In total, this evidence strongly suggests that although CRP appears to be involved in NK-mediated killing, it is not involved in effector-target cell-mediated recognition.

Antibodies↗
PubMed1986

Binding of C-reactive protein to nucleated cells leads to complement activation without cytolysis.

C-reactive protein (CRP) is an acute-phase reactant that is found bound to cells at sites of inflammation. We have passively sensitized HEp-2 cells for CRP binding and examined the effect of this treatment on complement activation and cell lysis. When cells were treated with protamine sulfate and CRP and were incubated with normal human serum in a 4-hr 51Cr-release assay, no significant lysis was noted. In contrast, HEp-2 cells treated with antibody and normal human serum were lysed. The consumption of complement components in normal human serum after incubation with cells treated with protamine and CRP was measured by hemolytic assays. CRP-treated cells consumed over 80% of C1, C4, and C2 and about 40% of C3 present. No significant consumption of C5 through C9 components was observed. Cells treated with antibody and complement showed consumption of C1 through C9. Cells were also sensitized for CRP binding by using diazophenylphosphocholine. This treatment also led to CRP binding and activation of the early classical pathway (C1, C4, C2, and to a lesser extent C3). The components of the membrane attack complex (C5 through C9) were not activated. Both a mouse monoclonal IgM and a human IgG antibody to phosphocholine activated the entire classical pathway. These results indicate that CRP activation of the classical complement pathway is restricted to the early part of the pathway. In the absence of activation of the membrane attack complex, complement-mediated cell lysis cannot occur.

Animals↗
PubMed1986

Effect of carbohydrate ingested on outcome in infants with mild gastroenteritis.

Children with mild acute gastroenteritis have not been observed for specific evidence of lactose intolerance yet are frequently fed a nonlactose formula. To determine whether such intervention is justified, 85 infants with mild acute gastroenteritis were followed prospectively. Infants were blindly and randomly assigned to 20 calorie/oz formula containing one of four carbohydrates: lactose, sucrose, polycose, or combined sucrose-polycose. Daily diaries were kept by parents, and patients were reexamined on days 2, 7, and 14 of the study. Evidence for rotavirus was detected in 23 infants, and five had bacterial pathogens. Symptoms resolved in most patients within 7 days, but five infants were subsequently hospitalized. Stool frequency, weight gain, and need for hospitalization did not differ significantly among the groups. Recovery from mild acute gastroenteritis occurred within 2 weeks irrespective of carbohydrate ingested.

Dietary Carbohydrates↗
PubMed1979

Complex of meningococcal group B polysaccharide and type 2 outer membrane protein immunogenic in man.

A noncovalent complex of meningococcal group B polysaccharide and type 2 outer membrane protein has been characterized and its potential as a vaccine against group B meningococcal disease investigated. The polysaccharide component was found to have a partition coefficient, K(d), of 0.34 on Sepharose CL-4B in the presence of sodium deoxycholate. The protein consisted of four to five major proteins including the principal outer membrane protein. Hydrophobic binding between the protein and polysaccharide was demonstrated by gel filtration and isopycnic CsCl density gradient centrifugation and found to involve all of the proteins. After demonstrating safety and immunogenicity in animals, two lots of vaccine were tested in a total of eight volunteers. Two 120-mug doses were given subcutaneously at 0 and 5 wk. Mild local reactions occurred in all eight volunteers, but no systemic reactions were observed. 2 wk after the first dose, six of the volunteers had increased levels of bactericidal antibodies against both the group B polysaccharide and the outer membrane proteins. Antibody rises to the group B polysaccharide (mean 6-fold) were confirmed by passive hemagglutination assays and rises to the proteins (mean 10-fold) by a solid phase radioimmunoassay. The second dose resulted in little or no increase in antibody titers. Antibody titers declined over a period of 14 wk but mostly remained above preimmunization levels. Bactericidal antibodies with specificity for the group B polysaccharide were mostly of the immunoglobulin (Ig)M class, and were directed against a determinant associated only with high molecular weight polysaccharides. We conclude that both the group B polysaccharide and the outer membrane protein are immunogenic in man when presented as a complex and that the complex warrants further testing and development as a vaccine against group B meningococcal disease.

Adult↗
PubMed1978

Specific cation effects on conformational transitions of DNA in aqueous solutions.

The circular dichroism (CD) and absorption spectral properties of calf thymus DNA have been examined in aqueous solutions containing varying concentrations of MgCl2, CaCl2, MnCl2, ZnCl2 and CoCl2. When the CD spectra were analyzed by methods previously described (Hanlon, S., Brundno, S., Wu, T.T. and Wolf, B. (1975) Biochemistry 14, 1648--1660), it was found that the spectral changes observed between 0 and 0.1 molal concentrations of each salt could be satisfactorily accounted for as a linear combination of two independent spectral components. One of these components had the spectrum which we had previously obtained in dilute solutions of NaCl (0.01-0.04 molal) and in 0.2 M tetramethyl ammonium chloride and attributed to a B-like structure. The other spectral endpoint was similar but not identical to the C spectrum obtained in the monovalent series. These differences were particularly pronounced for the transition metal ions, Mn2+, Zn2+ anc Co2+. Since significant band shifts were also observed in the absorption spectra of DNA in the presence of these transition metal ions, we have concluded that the differences observed between the C spectrum previously reported and that found for these ions is attributable to changes in the absorption properties of the monomers due to cation association, rather than dramatic differences in comformational properties of the C secondary structure of DNA in the presence of these ions. The greater efficiency of these divalent ions compared to the monovalent ions previously studied in effecting the B leads to C transconformational reaction is attributed to the more effective screening of electrostatic interactions, both along the phosphate backbone, and between sites on the bases which bear partial negative charges and the negatively charged phosphate groups. In the light of these present results, we believe that it is this electrostatic factor which is primarily involved in effecting the transition from a B to a more C-like state. The role of dehydration is viewed as a subsidiary one which facilitates better ion association, especially at the weaker base sites, thus effecting better damping of the repulsive electrostatic interactions.

Animals↗
PubMed1978

Safety and immunogenicity of a Neisseria meningitidis type 2 protein vaccine in animals and humans.

Two Neisseria meningitidis vaccines consisting principally of outer membrane protein (lot 138I-0) or outer membrane protein plus group C polysaccharide (lot 138I-M1) were prepared from the group C type 2 strain 138I. Lipopolysaccharide and lipid were removed by gel filtration in the presence of sodium deoxycholate. The vaccines were found to be nontoxic and nonpyrogenic in animals. They provided active protection in mice against mucin-enhanced killing by group B type 2 meningococci and induced good titers of type-specific bactericidal and hemagglutinating antibodies in rabbits. In five volunteers the vaccines were well tolerated and induced significant increases in serum bactericidal activity against both group C and group B strains. Three of five volunteers had a two- to fourfold increase in antibodies to the outer membrane proteins, but these antibodies did not appear to have bactericidal activity. The bactericidal antibodies to both group B and group C strains were directed against the capsular polysaccharides.

Animals↗
PubMed1977

Structural transitions of calf thymus DNA in concentrated LiCl solutions.

The solubility, sedimentation, circular dichroism, and absorption spectral characteristics of calf thymus DNA have been examined in concentrated solutions of LiCl (6-13 m) at 25 to 27 degree C. At all concentrations of LiCl, the DNA is base stacked and exhibits normal hypochromicty, At the upper end of this range of LiCl concentrations, DNA aggregates and ultimately precipitates completely from solution between 13 and 14 m LiCl. This aggregation process is dependent on concentration, base composition, and molecular weight of DNA. The sedimentation velocity data taken together with the absorbance spectral data suggest that the aggregation process leading to the formaiton of large structures beings at approximately equal to 9 m. Prior to the onset of aggregation, the circular dichroism (CD) spectra can be adequately fitted by a linear combination of contributions of the B, C, and A forms of DNA (Hanlon, S., Brudno, S., Wu, T. T., and Wolf, B. (1975), Biochemistry 14, 1648). Above 9 m LiCl, both factor analysis and a primitive version of matrix rank order analysis indicate that at least one additional spectral component is required to account for the observed CD spectra above 260 nm. The general shape of this additional component or distortion resembles the psi form of DNA.

Animals↗
PubMed1976

Sublimation of formaldehyde in freeze-drying.

Formaldehyde solution, commonly used to inactivate bacterial, rickettsial and viral suspensions during the preparation of vaccines, is known to have a deleterious effect on many antigens during freeze-drying. Sublimation of formaldehyde in shell-frozen and plug-frozen aqueous samples was investigated by measuring the residual formaldehyde periodically during the freeze-drying procedure. It was found that formaldehyde, even while subliming, concentrated on a volume basis. This was more apparent with the plug-frozen than with the shell-frozen material. Moreover, in the preparations taken to dryness, the formaldehyde polymerized to form paraformaldehyde. It was found that the addition of methanol not only prevented polymerization, but also significantly increased the sublimation of formaldehyde without concentration of the latter.

Acetals↗
PubMed1975

Prostaglandin E2 effects on cation flux in sickle erythrocyte ghosts.

Prostaglandin E2 has previously been shown to enhance the shape transformation of sickle prone erythrocytes (8) and to reduce the oxygen resaturation of Hemoglobin SS within intact sickle cell erythrocytes after deoxygenation (15). In view of the recent importance attributed to calcium transport in maintaining erythrocyte shape and viability (10) and the suggestion that prostaglandins may act via a calcium ionophore mechanism (9) on cell membranes, erythrocyte ghosts were prepared following the method of Lepke and Passow (12) from normal and sickle cell anemia erythrocytes. These two classes of ghosts are shown to display differing patterns of sodium and calcium transport, whith calcium influx being preferentially stimulated by prostaglandin E2 in sickle cell ghosts. It is suggested that in hypoxic, stasis conditions in vivo, prostaglandins may play a role in accelerating sickling of sickle prone erythrocytes via stimulation of calcium influx.

Anemia, Sickle Cell↗