Biomedical subjects

Klaus Pelz

Publications and source records attributed to Klaus Pelz.

6 recordsLinked to original sources

PubMed2006

Antibacterial effect of an ozone device and its comparison with two dentin-bonding systems.

Microorganisms remaining beneath restorations can cause secondary caries and pulp damage. Because of this, antimicrobial treatment could be useful. The aim of this study was to evaluate the antibacterial effect of the HealOzone device on Streptococcus mutans and to compare it with the already proven activity of two dentin-bonding systems. Thirty-five human molars were divided into 5 groups. Cavities were then cut into the teeth (n = 28 cavities per group). After sterilization, the teeth were left in broth cultures of 10(6) colony-forming units (CFU) ml(-1) of S. mutans at 36 degrees C for 48 h. The appropriate treatment followed (group A, control; group B, Clearfil SE Bond; group C, Clearfil Protect Bond; group D, 40 s of treatment with ozone; and group E, 80 s of treatment with ozone), and the cavities were then filled with composite resin. After 72 h, the restorations were removed, dentin chips were collected with an excavator, and the total number of microorganisms was determined. All treatments significantly reduced the number of S. mutans present compared with the control group. The antimicrobial effect of both bonding systems and treatment with 80 s of ozone was significantly higher than the 40 s ozone treatment. In conclusion, HealOzone and the bonding systems show striking antimicrobial effects against S. mutans.

Anti-Bacterial Agents↗

PubMed2005

Cytochemical differences in bacterial glycocalyx.

To examine new cytochemical aspects of the bacterial adhesion, a strain 41452/01 of the oral commensal Streptococcus sanguis and a wild strain of Staphylococcus aureus were grown with and without sucrose supplementation for 6 days. Osmiumtetraoxyde (OsO4), uranyl acetate (UA), ruthenium red (RR), cupromeronic blue (CB) staining with critical electrolytic concentrations (CECs), and the tannic acid-metal salt technique (TAMST) were applied for electron microscopy. Cytochemically, only RR-positive fimbriae in S. sanguis were visualized. By contrast, some types of fimbriae staining were observed in S. aureus glycocalyx: RR-positive, OsO4-positive, tannophilic and CB-positive with ceasing point at 0.3 M MgCl2. The CB staining with CEC, used for the first time for visualization of glycoproteins of bacterial glycocalyx, also reveals intacellular CB-positive substances-probably the monomeric molecules, that is, subunits forming the fimbriae via extracellular assembly. Thus, glycosylated components of the biofilm matrix can be reliably related to single cells. The visualization of intracellular components by CB with CEC enables clear distinction between S. aureus and other bacteria, which do not produce CB-positive substances. The small quantities of tannophilic substances found in S. aureus makes the use of TAMST for the same purpose difficult. The present work protocol enables, for the first time, a partial cytochemical differentiation of the bacterial glycocalyx.

Coloring Agents↗

PubMed2004

Investigations on the influencing of the subgingival microflora in chronic periodontitis. A study in adult patients during fixed appliance therapy.

AIM: The aim of the present study was to investigate changes in the subgingival flora in adults with chronic periodontitis undergoing orthodontic fixed appliance therapy. PATIENTS AND METHODS: In seven adult patients who had undergone nonantibiotic periodontal pretreatment, the subgingival bacteria were subjected to microbiological examination and the number of periodontopathogenic organisms was determined before (T1: prior to treatment being started), during (T2: 6 weeks after orthodontic treatment was started) and after the end of orthodontic treatment (T3: 6 weeks after removal of the fixed appliances). RESULTS AND CONCLUSION: During the fixed appliance therapy (metal brackets, NiTi archwires, stainless steel archwires), a marked reduction was observed in the total bacteria count from the subgingival pocket despite the clinical periodontal parameters remaining almost unchanged. However, the total count of some highly pathogenic bacteria rose again slightly after the end of treatment. We attribute the marked improvement in the periodontopathogenic bacteria spectrum under fixed appliance therapy with metal brackets, NiTi archwires and stainless steel archwires to metal corrosion entailing the release of primarily nickel ions, which have a toxic effect on bacteria and thus enable the regeneration of the physiological bacterial flora. In none of the patients was a deterioration of the periodontal status observed during and after fixed appliance therapy.

Adult↗

PubMed2004

Novel avilamycin derivatives with improved polarity generated by targeted gene disruption.

The oligosaccharide antibiotics avilamycin A and C are produced by Streptomyces viridochromogenes Tu57. Both consist of a heptasaccharide chain, which is attached to a polyketide-derived dichloroisoeverninic acid moiety. They show excellent antibiotic activity against Gram-positive bacteria. Both molecules are modified by O-methylation at different positions, which contributes to poor water solubility and difficulties in galenical drug development. In order to generate novel avilamycin derivatives with improved polarity and improved pharmacokinetic properties, we generated a series of mutants with one, two, or three mutated methyltransferase genes. Based on the structure of the novel avilamycin derivatives, the exact function of three methyltransferases, AviG2, AviG5, and AviG6, involved in avilamycin biosynthesis could be assigned.

Gene Targeting↗

PubMed2003

Tuboovarian abscess caused by Atopobium vaginae following transvaginal oocyte recovery.

A 39-year-old woman with tubarian sterility fell ill with acute pelvic inflammatory disease 2 months after transvaginal oocyte recovery. Laparotomy revealed a large tuboovarian abscess, from which Atopobium vaginae, an anaerobic gram-positive coccoid bacterium of hitherto unknown clinical significance, was isolated. The microbial etiology and the risk of pelvic infections following transvaginal punctures are discussed.

Abscess↗

PubMed2002

Small intestinal bacterial overgrowth in human cirrhosis is associated with systemic endotoxemia.

OBJECTIVES: Systemic endotoxemia has been implicated in various pathophysiological sequelae of chronic liver disease. One of its potential causes is increased intestinal absorption of endotoxin. We therefore examined the association of small intestinal bacterial overgrowth with systemic endotoxemia in patients with cirrhosis. METHODS: Fifty-three consecutive patients with cirrhosis (Child-Pugh group A, 23; group B, 18; group C, 12) were included. Jejunal secretions were cultivated quantitatively and systemic endotoxemia determined by the chromogenic Limulus amoebocyte assay. Patients were followed up for 1 yr. RESULTS: Small intestinal bacterial overgrowth, defined as > or = 10(5) total colony forming units per milliliter of jejunal secretions, was present in 59% of patients and strongly associated with acid suppressive therapy. The mean plasma endotoxin level was 0.86 +/- 0.48 endotoxin units/ml (range = 0.03-1.44) and was significantly associated with small intestinal bacterial overgrowth (0.99 vs 0.60 endotoxin units/ml, p = 0.03). During the 1-yr follow-up, seven patients were lost to follow up or underwent liver transplantation and 12 patients died. Multivariate Cox regression showed Child-Pugh group to be the only predictor for survival. CONCLUSIONS: Small intestinal bacterial overgrowth in cirrhotic patients is common and associated with systemic endotoxemia. The clinical relevance of this association remains to be defined.

Adult↗