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PubMed1975

Efficacy of modified human immune serum globulin in the treatment of experimental murine infections with seven immunotypes of Pseudomonas aeruginosa.

Modified immune serum globulin, prepared from human immune serum globulin by a nonenzymatic method, is apparently safe for intravenous administration to humans. The efficacy of the preparation was determined in experimental murine infections with seven immunotypes of Pseudomonas aeruginosa. Intravenously administered 0.85 percent NaCl, 0.3 m glycine, and 10 percent human albumin did not protect against lethal pseudomonas infection, whereas modified immune serum globulin given by the same route did protect mice. In the mouse protection test, the mean dose of the preparation that saved 50 percent of mice infected with any of eight strains of P. aeruginosa was 480 mg/kg (range, 12-2,333 mg/kg). For five strains the 50 percent effective dose was smaller than 200 mg/kg. There was no correlation between the efficacy of modified immune serum globulin in the mouse protection test and titers of antibody, as determined by bacterial agglutination. Therapy of pseudomonas infection in mice with modified immune serum globulin was followed by a prompt and persistent decrease in the numbers of intraperitoneal bacteria. This finding is consistent with the interpretation that modified immune serum globulin acts primarily as an opsonin and not as an antitoxin. Modified immune serum globulin may prove to be useful in the treatment of human infections.

Agglutination Tests↗

PubMed1981

Z-DNA conformation of N-2-acetylaminofluorene modified poly(dG-dC).poly(dG-dC) determined by reactivity with anti cytidine antibodies and minimized potential energy calculations.

The conformation of poly(dG-dC).poly(dG-dC), poly(dG).poly(dC), and calf thymus DNA modified with N-acetoxy-N-2-acetylaminofluorene (N-acetoxy-AAF) was examined by extent of reaction with anti cytidine antibodies. In contrast to modified poly(dG).poly(dC0 and DNA, modified poly(dG-dC).poly (dG-dC) failed to react with the antibodies indicating that the base pairing in this polymer is intact. This in consistent with induction of the Z-DNA conformation in AAF modified poly(dG-dC).poly(dG-dC). Using minimized potential energy calculations on the dCpdG-AAF dimer as a model for the modified polymer, it is shown that the proposed Z-DNA conformation is energetically stable. A model is proposed for an AAF modified tetramer, dGpdCpdGpdC, in which the AAF is external to the Z-DNA duplex.

2-Acetylaminofluorene↗

PubMed1978

Characterization of phospholipase A activity of beta1-bungarotoxin from Bungarus multicinctus venom. II. Identification of the histidine residue of beta1-bungarotoxin modified by p-bromophenacyl bromide.

beta1-Bungarotoxin modified with p-bromophenacyl bromide (BPB) was reduced and carboxymethylated, and the resulting two constituent RCM-polypeptide chains (the RCM-A and B chains) were separated. The RCM-A chain was found to be modified by BPB by measuring its UV absorption spectrum and was shown to have lost one histidine residue by analyzing its amino acid composition. To determine the location of the modified histidine residue in the A chain of the toxin, the RCM-A chain was digested with TPCK-trypsin, and the resulting peptides were fractionated by gel filtration followed by DEAE-cellulose chromatography. The modified residue was finally identified as histidine-48 in the A chain by Edman degradation and from the amino acid composition of the BPB-modified peptide. The amino acid sequence around the modified histidine residue in the A chain is highly homologous with those of porcine pancreas phospholipase A2 and presynaptic toxin, notexin. We conclude that histidine-48 in the A chain participates in the phospholipase A activity of beta1-bungarotoxin.

Acetophenones↗

PubMed1984

Bindings of Ca2+ and substrate analogs to a cobra venom phospholipase A2 in which the alpha-amino group is modified to an alpha-keto group.

The pH dependence of the chemical reaction rate of p-bromophenacyl bromide (BPB) with His 48 of cobra (Naja naja atra) venom phospholipase A2, in which the alpha-NH2 group had been selectively modified to an alpha-keto group, was studied at 25 degrees C and ionic strength 0.1 in the absence of Ca2+. The pH-dependence curve was monophasic with a midpoint at pH 7.9, which corresponds to the pK value of His 48 of the alpha-NH2-modified enzyme, whereas the curve for the intact enzyme was biphasic, indicating participation of two ionizable groups with pK values of 7.3 and 8.55 (Teshima et al. (1982) J. Biochem. 91, 1778-1788). These two groups were thus identified as His 48 and the alpha-NH2 group, respectively. The pH dependence of the binding constant of Ca2+ to the alpha-NH2-modified enzyme was studied at 25 degrees C and ionic strength 0.1 by measuring the tryptophyl fluorescence changes. The pH-dependence curve was very similar to that for the intact enzyme (Teshima et al. (1981) J. Biochem. 89, 13-20), and it was interpreted in terms of participation of His 48 and Asp 49 (pK 5.4). The absence of participation of the alpha-NH2 group in the Ca2+ binding was thus confirmed. Bindings of monodispersed n-dodecylphosphorylcholine (n-C12PC) and micellar n-hexadecylphosphorylcholine (n-C16PC) to the alpha-NH2-modified enzyme were studied at 25 degrees C and ionic strength 0.1 by the aromatic circular dichroism (CD) and tryptophyl fluorescence methods, respectively. The binding constant of the monodispersed substrate was very similar to that for the intact enzyme (Teshima et al. (1981) J. Biochem. 89, 1163-1174). The binding constant of the micellar substrate to the modified enzyme in the presence of Ca2+ was also very similar to that for the intact enzyme-Ca2+ complex (Teshima et al. (1983) J. Biochem. 94, 223-232), and the pH-dependence curve was interpreted in terms of participation of His 48. On the other hand, the binding constant of the micellar substrate to the modified apoenzyme was much smaller than that for the intact apoenzyme. Nevertheless, the pH-dependence curve could be interpreted in terms of participation of His 48 and Asp 49. From these findings, it was concluded that the ionization state of the alpha-NH2 group of cobra venom phospholipase A2 is essentially irrelevant to the bindings of Ca2+ and also of the monodispersed and micellar substrates.

Animals↗

PubMed1985

Modified essay question.

This article examines the reliability and validity of the modified essay question. An 18-item modified essay question was developed and pretested on a group of clinical experts. After the pretest, the modified essay question was administered to a group of 25 physical therapy students immediately before their second level orthopedic placement. A reliability index of .39 (coefficient alpha) was calculated for the test. In addition, measures of validity were obtained by correlating the modified essay question scores with multiple-choice question scores and the students' in-clinic reasoning scores. The results suggest that the reliability coefficient found in this study is comparable to the medical literature. Also, the results showed that the modified essay question demonstrated a greater correlation with the in-clinic clinical reasoning score compared with the parallel content multiple-choice examination. Furthermore, preliminary evidence suggests that the modified essay question may be a useful paper and pencil tool in evaluating clinical reasoning. Finally, several shortcomings of this study are discussed in conjunction with a direction for further study.

Adult↗

PubMed1990

The generation of cytotoxic T lymphocytes against acetaldehyde-modified syngeneic cells.

The major metabolic product of ethanol is acetaldehyde. It is highly reactive with proteins. In situ this modification is significant enough to generate an antibody response. Whether an effector cellular immune response can be generated against these acetaldehyde modified adducts on syngeneic cells is not known. In this paper we have demonstrated in the murine system that acetaldehyde modified splenic cells can generate cytotoxic T lymphocytes (CTL). These CTL are specific for the acetaldehyde modified syngeneic cells, and not acetaldehyde modified allogeneic cells. The ability of the CTL to lyse-specific targets is dependent on the formation of stable acetaldehyde adducts. Cold target inhibition studies reveal that modified syngeneic cells can inhibit lysis as effectively as unmodified cells. Therefore, the present study lends support to the hypothesis that acetaldehyde modified cells can generate a cellular immune response and may do so in pathologic states.

Acetaldehyde↗

PubMed1993

Characterization of a heat-modifiable outer membrane protein of Haemophilus somnus.

In immunoblot analysis, a murine monoclonal antibody (MAb), 27-1, which was produced to an outer membrane protein (OMP) of Haemophilus somnus, showed that a major OMP is heat modifiable, having a molecular mass of 28 kDa when the N-lauroylsarcosine-insoluble OMP preparation was solubilized at 60 degrees C and a mass of 37 kDa when the OMP preparation was solubilized at 100 degrees C. The heat-modifiable OMP reacted intensely with convalescent sera obtained from calves with experimental H. somnus pneumonia in immunoblot analysis. Immunoelectron microscopic and antibody absorption studies revealed that the MAb 27-1 epitope was not surface exposed on the intact bacterium. However, a decrease in antibody reactivity to the heat-modifiable OMP in immunoblot analysis after absorption of convalescent serum with intact bacterial cells of H. somnus suggests that a surface-exposed portion of the heat-modifiable OMP is expressed on the intact bacterium. MAb 27-1 reacted with 45 of 45 strains of H. somnus tested in immunoblot analysis. The apparent molecular mass of the antigen varied among strains, and five reactivity patterns demonstrated by MAb 27-1 were observed. MAb 27-1 also reacted with six species in the family Pasteurellaceae, Escherichia coli, and Salmonella dublin, but not with the other eight species of gram-negative bacteria. The heat-modifiable OMP of H. somnus showed immunological cross-reactivity with the OmpA protein of E. coli K-12 and significant N-terminal amino acid sequence homology with the OmpA proteins of gram-negative bacteria. We conclude that a major, 37-kDa heat-modifiable OMP of H. somnus, which elicits an antibody response in H. somnus-infected animals, is a common antigen among H. somnus strains tested and is structurally related to the OmpA protein of E. coli.

Amino Acid Sequence↗

PubMed1982

Immunological detection of the Kanagawa phenomenon of vibrio parahaemolyticus on modified selective media.

Selective media for Vibrio parahaemolyticus, BTB-Teepol agar and modified arabinose-ammonium sulfate-cholate agar, were modified for use in immunological detection of the thermostable direct hemolysin produced by this organism. The modified BTB-Teepol agar and modified arabinose-ammonium sulfate-cholate agar were both found to be useful for the modified Elek test and immunohalo test with antiserum (or immunoglobulin G) against the thermostable direct hemolysin. With these modified media it is possible to isolate V. parahaemolyticus and identify the Kanagawa phenomenon on a single plate and thus save time in obtaining results.

Culture Media↗

PubMed1983

Antibodies against polyethylene glycol produced in animals by immunization with monomethoxy polyethylene glycol modified proteins.

Antibodies to polyethylene glycol (PEG) were raised in rabbits by immunization with monomethoxy polyethylene glycol modified ovalbumin (OA), bovine superoxide dismutase (SOD), and ragweed pollen extract (Rag), given in Freund's complete adjuvant (FCA). Immunogenicity depended on the nature of the protein and the degree of modification. With modified OA, in the presence of FCA, the majority of animals showed an anti-PEG response. With modified SOD and Rag only a small proportion of animals responded. In the absence of FCA, modified OA, given s.c., did not elicit any anti-PEG antibody response in rabbits and only a weak response in mice. PEG of MW 10,000 and 100,000 given in FCA was found nonimmunogenic in rabbits, and PEG of MW 5.9 X 10(6), given s.c. to mice, showed no or very poor immunogenic properties. Gel diffusion, heterologous passive anaphylaxis and passive hemagglutination were used to demonstrate anti-PEG antibodies raised to PEG-modified proteins. Specificity was confirmed by hapten inhibition of precipitation, inhibition of passive hemagglutination and cross-reactivity tests. PEG of MW greater than or equal to 4,000 produced specific precipitates, smaller molecules acted as monovalent haptens. From hapten inhibition of precipitation by PEG of MW 300 it appears that the antigenic determinant of PEG may be a sequence of 6-7 -CH2CH2O-units. Anti-PEG antibodies can be used analytically. By gel diffusion, Peg was detected in minimal concentrations of 0.1-1 microgram/ml. The clinical relevance of these findings with regard to therapy with PEG-modified enzymes and allergens in humans remains to be established.

Animals↗

PubMed1994

Stimulation with a monoclonal antibody (mAb4E4) of scavenger receptor-mediated uptake of chemically modified low density lipoproteins by THP-1-derived macrophages enhances foam cell generation.

mAb4E4, a murine monoclonal antibody that is specific for acetylated LDL and malondialdehyde-treated LDL, binds specifically to modified LDL present in human atherosclerotic lesions. It is directed against an epitope that is poorly exposed in delipidated and solubilized apolipoprotein B-100 from modified LDL. mAb4E4, as well as its F(ab')2 and Fab fragments, enhanced the uptake of both acetylated LDL and malondialdehyde-treated LDL by THP-1-derived macrophages resulting in a sixfold increase of cytoplasmic cholesteryl ester levels. The increased uptake of modified LDL/mAb4E4 complexes did not occur via the Fc receptor and did not depend on aggregation of modified LDL particles. However, their uptake was inhibited by blocking the scavenger receptors with fucoidin or by downregulation of receptor expression with endotoxins or interferon-gamma, indicating that their uptake is mediated via these receptors. Thus, generation of autoimmune antibodies against modified LDL and subsequent endocytosis of soluble modified LDL/antibody complexes via scavenger receptors may enhance foam cell generation. This mechanism may contribute to the progression of atherosclerotic lesions.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed1995

Malondialdehyde-modified low density lipoproteins in patients with atherosclerotic disease.

The murine monoclonal antibody mAb-1H11 raised against malondialdehyde (MDA)-modified LDL, was used to detect cross-reacting material in human atheromatous tissue and in plasma. MDA-modified LDL levels in plasma were 0.19 +/- 0.02 mg/dl (mean +/- SEM) in 44 control subjects, 0.24 +/- 0.02 mg/dl in 15 patients with chronic stable angina pectoris (P = NS vs LDL cholesterol matched controls), 1.4 +/- 0.1 mg/dl in 60 patients with acute myocardial infarction (P < 0.001 vs controls), and 0.86 +/- 0.11 mg/dl in 22 patients with carotid atherosclerosis (P < 0.001 vs controls). Modified LDL, isolated from pooled LDL of 10 patients, showed a higher electrophoretic mobility on agarose gels, a higher content of thiobarbituric acid reactive substances, and a higher cholesterol/protein ratio than native LDL and had a similar reactivity (antigen/protein ratio) in the assay as the in vitro MDA-modified LDL used for calibration. Its apo B-100 moiety was not fragmented. Uptake of this modified LDL by macrophages resulted in foam cell generation. In conclusion, elevated plasma levels of atherogenic MDA-modified LDL may be a marker for unstable atherosclerotic cardiovascular disease.

Aged↗

PubMedDate not supplied

Modified release tizanidine: a review.

The pharmacokinetic and clinical properties of a modified release formulation of the alpha 2-adrenergic agonist tizanidine are reviewed. Therapy with conventional tizanidine tablets is effective in the relief of spasticity, but it has a short half-life, resulting in it having to be administered three or four times daily. The modified release capsules have retard characteristics which allow the drug to be given as a once-daily dosage. Single- and multiple-dose pharmacokinetic studies in healthy volunteers have shown that the relative bioavailability of the modified release formulation is similar to that of conventional tablets and is unaffected by food. Clinical studies have shown that modified release tizanidine improved spasticity and disability in approximately 94% and 79%, respectively, of spastic patients. Adverse effects were observed in about 33% of patients. Mild, transient muscular weakness was the most common effect, but it did not require termination of treatment. Body weight, blood pressure, heart rate and haematological or biochemical measures were not adversely affected. The initial recommended dose of modified release tizanidine is one capsule per day of 6 mg, which may be increased gradually to 24 mg. A daily dose of 12 mg modified release tizanidine was used in 50% of patients studied.

Biological Availability↗

PubMed1989

Microtubules rich in modified alpha-tubulin characterize the tail processes of motile fibroblasts.

The organisation of microtubules rich in post-translationally modified alpha-tubulin has been investigated in a fibroblast cell line (NIH-3T3-T15) that can be reversibly transformed. An immunofluorescence microscopy study of the static non-transformed cells has revealed a central distribution of wavy microtubules showing post-translational modifications. When transformed there is a marked increase in cell motility and the appearance of long thin cytoplasmic 'tails'. These tails have been found to contain conspicuous bundles of post-translationally modified microtubules that run down the length of the processes and terminate close to the plasmalemma. Both detyrosinated and acetylated alpha-tubulin are present as major species in these modified microtubules. Such a pattern of modified microtubules is only occasionally seen in the untransformed NIH-3T3-T15 cells. We have also found them to be present in other transformed fibroblast lines. The presence of bundles of microtubules rich in modified alpha-tubulin in the cell tails is correlated with a marked reduction in the numbers of F-actin stress fibres. The possible role of these modified stable microtubules in cell motility is discussed.

Cell Line↗

PubMed2024

Design and evaluation of antisense sequence length for modified mouse U7 small nuclear RNA to induce efficient pre-messenger RNA splicing modulation in vitro.

Pre-messenger RNA (pre-mRNA) splicing modulation is an attractive approach for investigating the mechanisms of genetic disorders caused by mis-splicing. Previous reports have indicated that a modified U7 small nuclear RNA (U7 snRNA) is a prospective tool for modulating splicing both in vitro and in vivo. To date, very few studies have investigated the role of antisense sequence length in modified U7 snRNA. In this study, we designed a series of antisense sequences with various lengths and evaluated their efficiency in inducing splicing modulation. To express modified U7 snRNAs, we constructed a series of plasmid DNA sequences which codes cytomegalovirus (CMV) enhancer, human U1 promoter, and modified mouse U7 snRNAs with antisense sequences of different lengths. We evaluated in vitro splicing modulation efficiency using a luciferase reporter system for simple and precise evaluation as well as reverse transcription-polymerase chain reaction to monitor splicing patterns. Our in vitro assay findings suggest that antisense sequences of modified mouse U7 snRNAs have an optimal length for efficient splicing modulation, which depends on the target exon. In addition, antisense sequences that were either too long or too short decreased splicing modulation efficiency. To confirm reproducibility, we performed an in vitro assay using two target genes, mouse Fas and mouse Dmd. Together, our data suggests that the antisense sequence length should be optimized for modified mouse U7 snRNAs to induce efficient splicing modulation.

RNA, Small Nuclear↗

PubMed1988

A longitudinal study comparing scaling, osseous surgery and modified Widman procedures. Results after one year.

The purpose of this study was to compare, longitudinally, the effectiveness of scaling and root planing, osseous surgery, and the modified Widman procedures. The study was carried out in a private practice setting. Sixteen adult patients with moderate to advanced adult periodontitis were treated with initial scaling and oral hygiene procedures. Posthygiene data were used for comparison of changes in probing depth, clinical attachment levels and gingival recession. The initial examination data were used to compare changes in plaque and gingival indices. Frequency distributions were used to compare changes that occurred at individual sites. At one year, plaque and gingival indices were significantly reduced when compared with the initial examination. At one year, shallow pockets (1-3 mm) were reduced when compared to posthygiene. Four- to six-millimeter pockets were significantly reduced by the three procedures. Osseous surgery and modified Widman had significantly greater pocket reduction when compared with scaling. For pockets greater than 7 mm, osseous surgery and the modified Widman had significantly greater reduction when compared with scaling. For pockets 1-3 mm at one year osseous surgery had significantly greater clinical attachment loss when compared with scaling. For 4-6 mm pockets at one year, the three procedures had slight gains in clinical attachment levels. The results were similar for pockets with greater than 7 mm. Interproximal soft tissue craters were measured for six postoperative weeks. Initially, the modified Widman had a higher percentage of soft tissue craters when compared with osseous surgery. At six weeks, however, there were no significant differences when the surgical procedures were compared. Recession was measured at each examination. Recession for 1-3 mm pockets at one year was greater for osseous surgery when compared with scaling and the modified Widman. Recession for 4-6 mm and greater than 7 pockets was greater for the surgical procedures than scaling. The results from this study indicate that with three-month maintenance recalls, both the modified Widman and osseous surgery are effective for pocket reduction, and each will produce a slight gain of clinical attachment over one year. Scaling was effective at maintaining attachment levels but was not as effective in reducing pocket depth.

Adult↗

PubMed1994

Evaluation of a simple modified radiographic alignment system for routine use.

Radiographic frames used for longitudinal studies may be in part unreadable for measuring crestal bone change. Sites may not be present on the film, or the measurement reliability may be compromised because of dissimilar geometry. Several techniques used to address this problem are expensive, time-consuming, and required great skill. For the present study a commercially-available alignment system was simply modified by addition of a reference pin in the bite block, facilitating the repositioning of the film holder for a second exposure. This study determined the ability of the modified instrument to: 1) improve the geometrical correspondence between serial radiographs; and 2) reduce the frequency of missed sites in the film. Two pairs of x-rays were taken for each of 40 subjects, 1 pair with the standard alignment instrument of an assigned site and 1 pair with the modified instrument of the contralateral site. Measurements of alveolar bone height were performed using the "side by side" technique. The modified instrument yielded significantly smaller measurement differences and a significantly better geometrical correspondence than the conventional system (P < 0.05). Also, the modified instrument yielded significantly greater (P < 0.01) readable sites (86%) as compared to the conventional instrument (62%). The simply-modified instrument facilitates the correct interpretation of serial radiographs.

Acrylic Resins↗

PubMed1991

Biologic response modifiers in primary immunodeficiency disorders.

OBJECTIVE: To propose a new classification for the primary immunodeficiency disorders and to review potential therapeutic applications of biologic response modifiers in these disorders. DATA SOURCE: Relevant articles were identified through a search of MEDLINE using the following indexing terms: primary immunodeficiencies (and subclassifications), and human immunomodulators (and subclassifications). STUDY SELECTION: Articles were critically reviewed and included if relevant. DATA SYNTHESIS: The primary immunodeficiency disorders are classified according to functional abnormalities, specifically, abnormalities in early cellular maturation, differentiation, regulatory cell function, enzymatic function, and cytokine responses. Such a classification clarifies the potential role of biologic response modifiers in primary immunodeficiency disorders. Intravenous gammaglobulin and histamine-2 (H2)-receptor blockers modify regulatory cell function; retinoids modify abnormal cellular differentiation, gene transfer and enzyme replacement can be applied in disorders characterized by specific functional gene abnormalities; and interferons modify abnormal cytokine responses. Interleukin-2, thymic hormones, transfer factor, and levamisole appear to affect multiple functional defects. CONCLUSIONS: Biologic response modifiers are currently important ancillary tools in the treatment of immunodeficiency disorders, and their therapeutic role will become even more important in the future. Multi-center cooperative trials of new and existing agents are needed to fully define their roles and efficacy in the treatment of these disorders.

Cytokines↗

PubMed1992

Uptake, intracellular transport, and degradation of polyethylene glycol-modified asialofetuin in hepatocytes.

Polyethylene glycol (PEG) is attached to proteins in order to increase their half-life in the circulation and reduce their immunogenicity in vivo. For many applications involving "targeting" molecules, it is important to know how PEG modification of the molecule affects its interaction with a receptor and the subsequent internalization, intracellular transport, and lysosomal degradation. As a model system, we used asialofetuin, which binds to the galactose receptor of hepatocytes, because removal of sialic acid exposes galactose residues. We modified asialofetuin by attaching various amounts of PEG of molecular weight 1900 or 5000. The preparations were labeled with 125I so that endocytosis and degradation could be followed in suspended hepatocytes. Depending on the number of PEG molecules attached, receptor-mediated uptake was affected to varying degrees. If two-thirds of the exposed amino groups of the asialofetuin molecule were modified, the rate of uptake decreased to less than one-fourth of controls; degradation of endocytosed molecules was 12% of controls. The reduction in endocytic uptake was due to a reduced rate of formation of the receptor-ligand complex. Subcellular frationation in density gradients showed that PEG-modified asialofetuin is transported intracellularly and degraded in the same manner as the native protein, but the rate of proteolysis is reduced. This observation explains the paradoxical result of experiments with injection of modified asialofetuin into rats in vivo: even though the clearance of one preparation of PEG-asialofetuin was much slower than that of the native protein, accumulation of radioactivity in the liver from the modified protein was twice as high. The hepatocytes accounted for 85% of the hepatic accumulation of either PEG-modified or native asialofetuin in vivo.

Animals↗