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At least 163 records · Page 9Linked to original sources
PubMed2001

Pulp capping with a modified bioglass formula (#A68-modified).

PURPOSE: To evaluate a modified Bioglass (Formula #68 (MBF68) when used as a pulp capping agent. MATERIALS AND METHODS: After exposure, the pulps were contaminated with saliva for 60s, rinsed, dried and treated with Consepsis, acting as a hemostatic and bactericidal agent. After drying the Consepsis, the MFB68, having been pre-mixed in sterile saline, was carefully deposited over the pulp exposure, covered with polycarboxylate cement and restored with the ProBond bonding resin system. A calcium hydroxide group was used as control. RESULTS: There was no evidence of mummification, the incidence of properly positioned dentin bridge formation was higher and the incidence of extruded dentin bridge formation was reduced.

Animals↗
PubMedDate not supplied

Antileukemic and cytogenetic effects of modified and non-modified esteric steroidal derivatives of 4-methyl-3-bis(2-chloroethyl)amino benzoic acid (4-Me-CABA).

The increase of the damaging effects on specific DNA sequences and the reduction of the subsequent toxicity of nitrogen mustards has been achieved by their chemical conjugation with modified steroids through an esteric bond. In an attempt to study the structure-activity relationships of these compounds, we synthesized eight steroidal esters of 4-methyl-3-bis(2-chloroethyl)aminobenzoic acid (4-Me-CABA). The anti-leukemic and cytogenetic effects of the parent alkylating agent were compared with those produced by the steroidal compounds, in vivo against leukemias P388 and L1210 and in vitro for induction of Sister Chromatid Exchanges (SCE) and on proliferation rate indices (PRI). The results demonstrate that the existence of the NH-CO group, either as an endocyclic lactamic or as an out of the ring amidic one but at axial conformation, at the steroid-carrier moiety is necessary for the expression of the antileukemic activity. The synthetic route for the preparation of the steroidal esters and their physicochemical data are also reported.

4-Aminobenzoic Acid↗
PubMed2006

Mortality in a large tuberculosis treatment trial: modifiable and non-modifiable risk factors.

SETTING: North America. OBJECTIVES: Tuberculosis (TB) patients in North America often have characteristics that may increase overall mortality. Identifying modifiable risk factors would allow for improvements in outcome. DESIGN: We evaluated mortality in a large TB treatment trial conducted in the United States and Canada. Persons with culture-positive pulmonary TB were enrolled after 2 months of treatment, treated for 4 more months under direct observation, and followed for 2 years (total observation: 28 months). Cause of death was determined by death certificate, autopsy, and/or clinical observation. RESULTS: Of 1075 participants, 71 (6.6%) died: 15/71 (21.1%) HIV-infected persons, and 56/1004 (5.6%) non-HIV-infected persons (P < 0.001). Only one death was attributed to TB. Cox multivariate regression analysis identified four independent risk factors for death after controlling for age: malignancy (hazard ratio [HR] 5.28, P < 0.0001), HIV (HR 3.89, P < 0.0001), daily alcohol (HR 2.94, P < 0.0001), and being unemployed (HR 1.99, P = 0.01). The risk of death increased with the number of independent risk factors present (P < 0.0001). Extent of disease and treatment failure/relapse were not associated with an increased risk of death. CONCLUSIONS: Death due to TB was rare. Interventions to treat malignancy, HIV, and alcohol use in TB patients are needed to reduce mortality in this patient population.

Adult↗
PubMedDate not supplied

Comparison of a modified Edward-type medium and a modified SP4-type medium for primary isolation of Mycoplasma gallisepticum (MG) from chickens vaccinated with the F strain of MG.

The efficacy of two media, an Edward-type medium (EPJ) and a modified SP4-type medium (SP4-PS), were compared for primary isolation of Mycoplasma gallisepticum (MG) from commercial layer chickens (n = 58) vaccinated with the live F strain of MG. Three groups of chickens that differed in the interval after vaccinal exposure to the F strain (32, 41, and 102 weeks) were studied at necropsy. Mycoplasma isolation was attempted from the trachea, sinus, and cloaca using lavage and swab techniques but was successful only from the trachea and sinus. MG was isolated from 39 (8.4%) of 463 culture attempts from 58 tracheal inocula and 58 sinus inocula. Isolation of MG was successful more frequently using EPJ medium than SP4-PS medium, and isolation occurred more often from the sinus than from the trachea. Of the 58 chickens studied, 19 (33%) were shown by culture to be infected with MG. Isolation was successful only from 32- and 41-week post-vaccination exposure groups. However, all chickens studied were serologically positive for MG antibody by rapid-plate agglutination and hemagglutination-inhibition assays.

Agglutination Tests↗
PubMed1975

Immunogenic properties of modified antigen E. III. Effect of repeated injections of modified antigen on immunocompetent cells specific for native antigen.

It has been shown that ragweed antigen E loses its major antigenic determinants after denaturation in 8 M urea, but urea-denatured (UD) antigen and an alpha-polypeptide chain isolated from the denatured molecules are capable of priming mouse T cells specific for native antigen. Weekly injections of 10mug UD antigen or alpha-chain into antigen E-primed animals depressed the ongoing IgE antibody response, whereas injections of the same dose of antigen E failed to depress the antibody response. It was found by adoptive transfer experiments that helper activity of antigen E-primed splenic T cells was depressed by the treatment of the donors with either modified antigen or native antigen E. The same treatment of antigen E-primed animals depressed the DNA synthetic response of their splenic T cells to antigen E. The treatment of antigen E-primed animals with UD antigen resulted in a decrease of antigen E-specific IgE-B cells and IgG-B cells in their spleen, whereas the treatment with native antigen expanded the B cell populations. In view of the results obtained in the mouse, cellular basis for the immunologic effects of hyposensitization treatment is discussed.

Animals↗
PubMed1983

Role of self carriers in the immune response and tolerance. VIII. Suppression of the MOPC-104E idiotypic response by idiotype-modified self, but not by dextran-modified self.

We have investigated the suppression of the anti-dextran B1355S immune response using our model of modified self. The anti-dextran response is idiotypically well defined in BALB/c mice. This system enables us to examine the contribution of various predominant idiotypes to the antibody response under conditions of suppression by antigen or by idiotype-specific suppressor cells. Our results demonstrate that the total anti-dextran response can be inhibited by pretreatment of animals with dextran-coupled syngeneic spleen cells; however, the representation of major idiotypes constituting this response are not reduced in percentage. In contrast, pretreatment of mice with MOPC-104E-coupled spleen cells leads to a specific suppression of the private IdI-104E idiotype. The total anti-dextran response remains unchanged, as well as proportions of other major idiotypes known (IdI-588 and IdX). This suppression is mediated by Thy-1.2+, Lyt-2.2+ T cells, as demonstrated by adoptive transfer assays. This system will allow the molecular dissection of the regulation of an idiotypically well-defined system for the suppression by either antigen- or idiotype-specific suppressor T cells.

Animals↗
PubMed1977

[Modified impregnation method for staining apical dendrite and spine (modified Golgi's method)].

A silver impregnation method for the demonstration of apical dendrites and spines in materials long preserved in folmalin is reported. This method is a modified version of Golgi's Silver method and consists of the following procedures: The formalin-fixed tissue blocks were incubated in a solution containing 3% potassium bichromate (150 ml), 96% ethyl alcohol (50 ml), and concentrated acetic acid (50 ml) for 24 hrs. at 37 degrees C, and 4 more days at room temperature after changing the solution twice. The tissue blocks were then kept for 5 days at room temperature in a 5% potassium bichromate solution. After making a thorough rinsing for one day in tap water and three washings in distilled water, the blocks were impregnated for 1/2 to 1 hr. in a 0.5% AgNO3 solution, for a further 4 days at room temperature in a 1% AgNO3 solution, washed three times briefly in distilled water and again impregnated for 4 to 5 days in a 2% AgNO3 solution. Following a thorough rinsing in distilled water the tissue blocks were embedded in paraffin and 50 to 100 micron sections were prepared.

Animals↗
PubMed1982

Inhibition of oxygen exchange by chemical modifiers at the sulfhydryl 1 or reactive lysine residue of myosin. Changing the rates of intermediate enzymatic reactions by modifying the course of reaction-linked conformational changes.

During the hydrolysis of MgATP by myosin, there is an extensive exchange of oxygen between water and the terminal phosphate group of bound nucleotide, which results from a repeated cycle of hydrolytic cleavage and its reversal. An analysis of the distribution of [18O]Pi species from the hydrolysis of [gamma-18O]ATP gives an estimate for the apparent rate constant [k-3(app)] of reverse cleavage, which is the rate-limiting step of the exchange cycle. We have performed this kind of analysis with two different forms of modified myosin, containing either N-ethylmaleimide at the sulfhydryl 1 group or trinitrophenyl at the reactive lysine residue. Although these modifications of the protein are chemically different, and the sulfhydryl 1 group and the reactive lysine residue are far apart in the primary chain of the myosin head, the two modifications caused a similar marked inhibition of oxygen exchange. This effect resulted from: 1) a decrease in the time available for the exchange cycle due to a 3-10-fold increase in the turnover rate of hydrolysis and 2) a reduction in k-3 (app) from 2-5 s-1 to 0.2-0.5 s-1. It is proposed that modifications of this type influence enzymatic activity by altering the course of "reaction-linked conformational changes," i.e. those changes in protein structure that are coupled to the catalytic mechanism but are not part of the substrate-binding site proper. It is also suggested that certain naturally occurring protein modifications, e.g. methylation of histidine or lysine residues, could regulate function by operation of this mechanism.

Adenosine Triphosphate↗
PubMed2000

The cannabinoid agonist HU 210 modifies rat behavioural responses to novelty and stress.

Experiments were performed on groups of rats after acute and sub-chronic treatment (once daily for 9 days) with the cannabinoid agonist HU 210 (25-100 microg kg(-1), i.p.) as well as 24 h and 7 days after the last drug injection. The animals underwent three behavioural tests in novel environments. In the observation cages (Test 1), rat locomotor activity was found to be dose-dependently reduced after acute and sub-chronic treatment at all doses and virtually unchanged during abstinence; grooming was potently inhibited by acute treatment but potentiated by the sub-chronic one at doses of 50 and 100 microg kg(-1), the effect of the higher dose persisting after 24 h and 7 days abstinence. Vocalization in animals in response to a tactile stimulus was highest after HU 210 at 100 microg kg(-1) in all experimental modes except after 7 days abstinence. In the X-maze (Test 2), sub-chronic HU 210 dose- dependently enhanced rat natural aversion for open arms, and this behaviour persisted during abstinence after the highest dose. Grooming in the X-maze was completely absent in rats acutely injected with HU 210 but potentiated in those sub-chronically treated or abstinent. In the swimming test (Test 3) rats sub-chronically treated at 50 and 100 pg kg(-1) displayed relevant wall-hugging and the same occurred 24 h after last injection. On the whole, our results are indicative of an anxiogenic-like effect of sub-chronic HU 210 at high doses and reflect the persistence of enhanced emotional response to novel environments when the treatment is discontinued.

Animals↗
PubMed1999

Modified primers for D12S391 and a modified silver staining technique.

In this paper we describe a new primer pair for the short tandem repeat (STR) D12S391 which makes it possible to obtain considerably shorter amplification fragments (125-173 bp), compared to the previously published primers (205-253 bp). The primers were tested on 70 samples with known genotypes, and no differing results were found. In sensitivity studies, forensic casework samples and DNA quality studies, we proved that the new primers can improve the efficiency of the amplification. Moreover, the resolution of this locus on denaturing PAGE followed by silver staining was dramatically improved. This improvement was found to be most valuable for typing the rare.3 variants known for this locus. We also present and propose a new method for silver staining denaturing acrylamide gels.

Alleles↗
PubMed1990

Modified reaction centers from Rhodobacter sphaeroides R26. 2: Bacteriochlorophylls with modified C-3 substituents at sites BA and BB.

Monomeric bacteriochlorophylls BA and BB in photosynthetic reaction centers from Rhodobacter sphaeroides R26 were exchanged with (13(2)-hydroxy-)bacteriochlorophylls containing a 3-vinyl- or 3-(alpha-hydroxyethyl)-substituent instead of the 3-acetyl group. The corresponding binding sites must be tolerant to the introduction of the polar residue at C-13(2) and modifications of the 3-acetyl group. According to HPLC analysis, the exchange with both pigments amounts to less than or equal to 50% of the total BChl contained in the complex, corresponding to less than or equal to 100% of the monomeric BChl alpha BA,B. The absorption spectra show significant changes in the QX and QY-region of the monomeric bacteriochlorophylls. By contrast, the absorption of the primary donor (P870) and reversible photobleaching is retained. The circular dichroism is also unchanged in the 870 nm region. The positive cd band located at around 800 nm in native reaction centers, shifts with the (blue-shifted) QY absorption(s) of BA and/or BB, whereas the position of the negative one remains nearly unaffected. The data indicate that the latter is the upper excitonic band of the primary donor, and that there is little interaction of the monomeric BA/BB with the primary donor.

Bacteriochlorophylls↗
PubMed1983

Demonstration of a minor hemoglobin with modified alpha chains and additional modified hemoglobins in normal and diabetic adults.

We have attempted to separate various hemoglobins in 10 normal and 11 diabetic persons by Bio-Rex 70 chromatography at 4 degrees C with an exponentially increasing sodium phosphate gradient. Minor hemoglobins, namely AIa1, AIa2, AIb1, AIb2, AIb3, AIc, AId1, AId2 and AId3, have been separated and eluted in that order. Most of these minor hemoglobins were newly observed and could not be detected by the previous chromatographic techniques. On the basis of colorimetric assay protein-bound ketoamine was present in all the minor hemoglobins, which was confirmed by chromatographic separation of hemoglobins after reduction with NaB3H4. All the minor hemoglobins, with the exception of Hb AIa1, HbIa2, and Hb AIb1, showed a 2-fold increase in the diabetic patients. Hb AIc (5.0% in normals; 9.0% in diabetics) and Hb AId3 (1.9% in normals; 3.2% in diabetics) were present in the largest amounts. Both Hb AId3 and Hb Ao showed a decrease in oxygen affinity in the presence of 2,3-diphosphoglycerate, whereas Hb AIc showed no effect. Separation of globin chains by cellulose acetate electrophoresis at pH 8.6 showed that the cathodal mobility of the alpha chains of Hb AId3 was slower than those of Hb Ao. Glycosylation of Hb with [14C]glucose followed by separation of hemoglobins by two Bio-Rex 70 chromatographic methods indicated that the minor Hb formed by glycosylation of the alpha-chain amino-terminus was separated from Hb Ao, while the minor hemoglobins formed by the glycosylation of epsilon-NH2 groups chromatographed with Hb Ao.

Chromatography, Ion Exchange↗
PubMed2004

Electron microprobe analysis into interactions of a resin-modified glass-ionomer cement and a modified composite with human dentin in vitro.

When materials used in restorative dentistry, such as a glass-ionomer cement or a compomer, were applied to dentin, ion exchanges occur between the material and the dentin. This work is based on an assessment in vitro of the ion exchanges occurring over time between (i) a glass-ionomer cement and dentin and (ii) a compomer and dentin. An electron microprobe analysis, technique not previously used for such a study, permitted qualitative and quantitative analysis of the interface and of the peripheral dentin. Analysis of the distribution of the elements in the interface and nearby showed continuous, progressive exchanges between the glass-ionomer cement and the dentin and absence of diffusion between the compomer and the dentin.

Adolescent↗