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Biomedical subjects

B Melzer

Publications and source records attributed to B Melzer.

At least 19 recordsLinked to original sources
PubMed2001

Plaque removal efficacy of two rotating/oscillating electric toothbrushes.

This study compared the plaque removal efficacy of the Philips Jordan HP510 and Braun Oral-B D9 electric toothbrushes in two clinical trials. In Trial I, a single-blind randomized split-mouth study, 24 subjects received an oral prophylaxis and abstained from all oral hygiene procedures for 24 hours before each quadrant was professionally brushed for 30 seconds. Plaque was scored before and after brushing using the Turesky-modified Quigley and Hein index (Q&H) and the approximal plaque index (API). Trial II was a two-week, single-blind balanced cross-over study comprising 54 subjects. At baseline, the subjects received an oral prophylaxis and instruction in the use of the assigned brush. Two weeks later, they returned to the clinic with 24-hour plaque accumulation. Plaque (Q&H, API) was scored before and after supervised brushing (30 sec/quadrant). After a prophylaxis, the subjects received the other brush with instructions on use, and the procedure was repeated. In Trial I, plaque was removed almost equally well by both brushes, with the HP510 and the D9 reducing Q&H from 1.46 and 1.47 (baseline) to 0.53 and 0.58, respectively, on average over all teeth. For the premolars and molars in particular, use of the HP510 resulted in statistically significantly lower Q&H scores than the D9 (0.70 vs. 0.81). In Trial II, the HP510 resulted in significantly better plaque scores than the D9 on Q&H (0.55 vs. 0.67) and API (23% vs. 28%) for all teeth. The buccal surfaces contributed the largest difference in Q&H. Statistically significant differences were also found in scores of the posterior teeth for Q&H (0.75 vs. 0.86) and API (31% vs. 38%). In conclusion, both rotating/oscillating electric toothbrushes were highly effective in plaque removal. The HP510 removed more plaque than the D9, particularly from the posterior teeth. It appeared that the smaller height and the Active Tip of HP510's brush head could have resulted in better posterior and approximal access.

Adult↗
PubMed1991

Application of the polymerase chain reaction to study the M protein(-like) gene family in beta-hemolytic streptococci.

Evaluation of homologous regions of published M protein (emm) gene sequences from group A streptococci (GAS; Streptococcus pyogenes) was used to design three primer pairs for polymerase chain reaction (PCR) and three oligonucleotide probe sequences internal to the amplified products. One set of primers and corresponding probe should detect and lead to amplification of emm(-like) genes of virtually every type ("all M"), another ("SOR-M") should only amplify emm(-like) genes from GAS negative for serum opacity reaction (SOR) and the third ("SOR+ M") should expand only emm(-like) genes from SOR+ GAS. Using the "allM" primer pair for PCR on the genomic DNA from GAS of 29 different M types as well as from a group C and a group G streptococcal isolate, DNA fragments within the expected size range were amplified in every assay. All PCR products reacted with the "allM" probe. Related sequences were not detected in genomic DNA of an S. agalactiae and an Enterococcus faecalis isolate. Applying the "SOR-M" and "SOR+M" primers to identical assays led to mutually exclusive amplification products. The "SOR-M" and "SOR+M" probes hybridized only to their corresponding products. Exceptions to this exclusivity were the SOR- GAS of M types 3, 8, 27, 34, 42, 67, and 69, which consistently reacted only with the "SOR+M" primer/probe set. Analysis of sequence data from the amplified emm(-like) 2, 3, 18, and 19 genes revealed interesting specific features such as conserved gaps in the C-terminal sequence regions from SOR+ and the exceptional SOR- GAS strains. These data indicate the existence of a subgroup of strains among SOR- GAS and may advance our understanding of phylogenetic relationship between different serotypes of GAS.

Amino Acid Sequence↗
PubMed1991

Molecular cloning and nucleotide sequence of a new plasmid-coded Klebsiella pneumoniae beta-lactamase gene (SHV-2a) responsible for high-level cefotaxime resistance.

Patient specimen isolates of Klebsiella pneumoniae exhibiting an MIC of greater than 128 mg/l for cefotaxime were shown to produce a beta-lactamase with a pI of 7.6, which is encoded on a 66 kb conjugative plasmid. A 3.5 kb Bam HI fragment of this plasmid was cloned into pLG339 and totally sequenced. The nucleotide sequence of the beta-lactamase gene presented 99% homology to those of SHV-2 and SHV-3, the deduced amino acid sequence differed from both enzymes in one and two positions, respectively, leading to the denomination SHV-2a for the new enzyme. Since the kinetic data of SHV-2a and SHV-2 are similar, too, quantitative effects mediated by distinctly different promotor regions are thought to be responsible for the elevated MIC for cefotaxime induced by SHV-2a.

Amino Acid Sequence↗
PubMed1991

Molecular characterization of a new plasmid-encoded SHV-type beta-lactamase (SHV-2 variant) conferring high-level cefotaxime resistance upon Klebsiella pneumoniae.

Between 1986 and 1988, multiresistant Klebsiella pneumoniae strains exhibiting high-level cefotaxime resistance were isolated from patient specimens particularly of the intensive care units of the Aachen Technical University Hospital. The resistance gene responsible was shown to be encoded on a conjugative 66 kb plasmid designated pZMP1. The MIC values for cefotaxime of the original isolates and the transconjugants were greater than 128 mg l-1 and 64 mg l-1, respectively. Isoelectric focusing of protein preparations from the transconjugants showed a beta-lactamase with a pI of 7.6. A 3.6 kb BamHI fragment containing the beta-lactamase gene was cloned into pLG339 resulting in the recombinant plasmid pZMP1-1. A restriction map of the cloned insert was established and PstI subfragments of the insert were further subcloned into pBGS18. The nucleotide sequence of the complete 3.6 kb fragment was determined. Within 3663 bp an open reading frame of 858 kb was found to show 99% homology to the SHV-2 and -3 nucleotide sequences. The deduced amino acid sequence differed in one and two positions, respectively, from these established SHV enzymes. The 3' noncoding sequence exhibited nearly perfect homology to that of SHV-2, but the 5' upstream sequence showed homology of less than 50% to the corresponding SHV-2 sequence, indicating an altered promoter region of the variant SHV-enzyme. Kinetic analysis of the beta-lactamase revealed a 50-100% elevated hydrolytic effectivity on cefotaxime in comparison to other SHV enzymes. Cefoxitin, ceftazidime, aztreonam and imipenem were not hydrolysed by the enzyme. The variant enzyme was inhibited by commonly available beta-lactamase inhibitors. Clavulanic acid had the highest affinity for the enzyme and the greatest effectivity in blocking its action. Based on the genetic and kinetic data we propose to classify the enzyme as a new variant beta-lactamase of the SHV-type and name it SHV-2a.

Base Sequence↗
PubMed1991

Different promoters of SHV-2 and SHV-2a beta-lactamase lead to diverse levels of cefotaxime resistance in their bacterial producers.

Clinical Klebsiella pneumoniae isolates as well as Escherichia coli transformants producing the beta-lactamases SHV-2 or SHV-2a demonstrate MIC values for cefotaxime of 4 mg l-1 or 64 to greater than 128 mg l-1, respectively. The beta-lactamases differ by one possibly insignificant amino acid exchange at position number 10 of the mature protein; their kinetic parameters are rather similar. The 5' untranslated regions of both corresponding genes show no homology starting 74 nucleotides upstream to the start codon. Hybridization of intragenically annealing oligonucleotides to dot-blotted serial dilutions of total cellular RNA from E. coli transformants harbouring these genes cloned into the same vector plasmid gave a positive signal down to 1.2 micrograms (SHV-2) and 0.32 to 0.16 micrograms (SHV-2a), indicating a four to eight times higher amount of specific transcript in the case of SHV-2a. By primer extension analysis and S1 nuclease digestion the starting point to transcription was located 100 nucleotides (SHV-2) and 50 nucleotides (SHV-2a) in front of the start codon. No other transcripts of different length could be detected after prolonged exposure. Northern blot analysis demonstrated the length of the beta-lactamase mRNA to be about 1.6 kb in both cases, thus comprising a potential open reading frame downstream of the two enzymes' genes. Selective PCR amplification of both promoter regions and of the structural gene of SHV-2 and subsequent combined cloning of each of the promoters and the SHV-2 gene into pBGS19 using a BamHI restriction site introduced by three point mutations into the cloned sequences was employed to transforms E. coli DH5 alpha.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1990

[Gunshot and explosion injuries of the hand].

The problem of hand injuries from bullets and explosives is covered in this paper by the example of three cases. The recommendation is made to remove only easily accessible projectiles. The damage caused by the intervention must not be larger than that caused by the bullet injury. Essential measures should include immediate wound toilet with removal of devitalised tissue, primary osteosynthesis, preferentially with minifixateur externe, coverage of exposed tendons, nerves, bones, and joints, splitting of the ligamentum carpi volare, perioperative administration of antibiotics, and secondary skin suture. Definite treatment should be left to a centre of hand surgery.

Adult↗
PubMed1989

[Interpretation of the influence of immunoglobulins and glycine on bacterial sensitivity to antibiotics in vitro].

The effect of human immunoglobulins (Ig) and of glycine, often added to commercial preparations as a stabilizer, have been examined in vitro on the growth of E. coli strains in the absence or presence of antibiotics in subminimal inhibitory concentrations (subMic). The Ig's (= 7S or 5S = F(ab')2 as well as glycine had no effect by themselves on bacterial growth at concentrations up to 32 mg and 4.5 mg per ml respectively. In contrast, in the presence of ampicillin, glycine induced a concentration dependent increase of bacterial sensitivity to antibiotics. This is apparently more pronounced in serosensitive than in seroresistant E. coli strains. Such a synergism could equally be shown with cefadroxil and fosfomycin, i.e. with other antibiotics interacting with cell wall synthesis, but not with those of another mode of action, as ciprofloxacin, polymyxin B or chloramphenicol.

Ampicillin↗
PubMed1986

Increased resistance towards two systemic experimental infections by tetrachlorodecaoxygen anion complex. Possible implications of cellular and humoral immunity.

The tetrachlorodecaoxygen anion complex (TCDO, Oxoferin) given intravenously 1 h after intravenous infection of mice with Candida albicans increased the host's resistance gradually in doses up to 3.1 mumol/kg body weight (b.w.). Above this level, the stimulatory effect decreased, turning to an inhibition at a dose of 18.6 mumol/kg b.w. TCDO. Repeated applications of the optimum single dose had no cumulative effect. In experimental infections with the strictly anaerobic Peptostreptococcus intermedius, TCDO ameliorated the course of the infection not only at a dose of 3.1 mumol/kg b.w. but also at a higher dose of 12.4 mumol/kg b.w. TCDO, which in the Candida sepsis model fell into the range of defence inhibition. A single dose of 3.1 mumol/kg b.w. TCDO also revealed to be the optimum dose to increase the humoral immune response evaluated by the number of immunoglobulin (Ig)M and IgG forming spleen cells after sensitization with sheep red blood cells (SRBC). The same results were obtained, regardless of whether TCDO had been given at the time of immunization or thereafter. The higher single dose of 18.6 mumol/kg b.w. TCDO did not show this effect but was not inhibitory either. Cellular immune reactions evaluated by the footpad swelling test and SRBC as antigen were found considerably enhanced whether TCDO was given once or repeatedly at a dose of 3.1 mumol/kg b.w., whereas single doses of 18.6 mumol/kg or repeated doses of 9.3 mumol/kg induced a certain inhibition.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[Influence of antibiotics on the production of interleukin-1 by macrophages].

Influence of cefoxitin and cefotaxime on interleukin-1 production (IL-1) by mice peritoneal resident macrophages activated by opsonized zymosan was investigated. Evaluation of the in vivo effect was done by examining macrophages of animals following intravenous administration of 30 mg/kg cefoxitin or cefotaxime. In vitro studies consisted in testing IL-1 production by macrophages in cell cultures in the presence of either antibiotic. In vivo IL-1 production was unchanged following cefoxitin treatment of cell donors, whereas a more than threefold increase was observed after administration of cefotaxime. In vitro, IL-1 production was enhanced by both antibiotics, but the pattern and extent of this effect diverged widely. Cefoxitin in a concentration of 300 micrograms/ml induced a threefold increase in IL-1 production. IL-1 production was increased tenfold and eightfold respectively by 150 and 300 micrograms/ml cefotaxime. When the concentration of either antibiotic was very high (400 micrograms/ml), the effect was significantly less important; a certain degree of inhibition was even observed with cefotaxime. Effects of cefoxitin and cefotaxime on IL-1 production and--as shown in previous studies--on prostaglandin E2 (PGE2) production and sensitivity of immunocompetent cells to PGE2 may be important factors in the mechanism of immunological side effects which result in a modulation of the course of experimental infection.

Animals↗