The virulence of Streptococcus mutans and the ability to form biofilms.

In some diseases, a very important role is played by the ability of bacteria to form multi-dimensional complex structure known as biofilm. The most common disease of the oral cavity, known as dental caries, is a top leader. Streptococcus mutans, one of the many etiological factors of dental caries, is a microorganism which is able to acquire new properties allowing for the expression of pathogenicity determinants determining its virulence in specific environmental conditions. Through the mechanism of adhesion to a solid surface, S. mutans is capable of colonizing the oral cavity and also of forming bacterial biofilm. Additional properties enabling S. mutans to colonize the oral cavity include the ability to survive in an acidic environment and specific interaction with other microorganisms colonizing this ecosystem. This review is an attempt to establish which characteristics associated with biofilm formation--virulence determinants of S. mutans--are responsible for the development of dental caries. In order to extend the knowledge of the nature of Streptococcus infections, an attempt to face the following problems will be made: Biofilm formation as a complex process of protein-bacterium interaction. To what extent do microorganisms of the cariogenic flora exemplified by S. mutans differ in virulence determinants "expression" from microorganisms of physiological flora? How does the environment of the oral cavity and its microorganisms affect the biofilm formation of dominant species? How do selected inhibitors affect the biofilm formation of cariogenic microorganisms?

Short-chain fatty acids in the saliva of patients with gastroesophageal reflux disease.

Gastroesophageal reflux disease (GERD) is a condition characterized by persistent symptoms and complications resulting from reflux of gastric contents into the esophagus. Short-chain fatty acids (SCFAs) are fermentation products of dietary fibres by the gut microbiota and are often studied for their anti-inflammatory and anticancer effects. The presence of SCFAs in the upper gastrointestinal tract, including in patients with GERD, has not been previously studied. The aim of this study was to investigate the relationship between the concentrations of SCFAs in the saliva of different age groups of patients with GERD. The study included 86 patients diagnosed with GERD, divided into two groups according to age: under and over 60 years of age, treated in the Gastroenterology and Hepatology Outpatient Clinic of the University Hospital in Cracow and 39 patients without gastrointestinal tract diseases. After clinical examination, blood was drawn to determine complete blood count, haemoglobin, and CRP. The oral cavity was examined, and unstimulated mixed saliva was collected. The SCFAs analysis was made by liquid chromatography-tandem mass spectrometry after facile derivatization coupled with liquid-liquid extraction. Of the six SCAFs studied, the highest median concentrations of acetic acid and propionic acid were observed in the saliva of patients with GERD and in the control group, in both the younger and older groups of patients. The concentrations of acetic acid and propionic acid were also higher compared with the four other fatty acids in the saliva of patients with GERD and in the control subjects. There were no correlations between salivary SCFAs levels and selected clinical and endoscopic parameters, including chronic inflammatory changes of the esophagus and stomach. In conclusions: SCFAs are present in the saliva of patients with GERD and in the control healthy persons. With the exception of valeric and isovaleric acids, salivary levels of SCFAs were significantly higher in patients with GERD compared to the control group. The highest concentrations of acetic acid and propionic acid were observed in patients with GERD and in both the younger and older patient groups. There were no differences in the concentrations of SCFAs in the saliva of female and male groups. We found no correlations between salivary SCFAs levels and selected clinical, laboratory and endoscopic changes of the oesophagus and stomach.

Angiotensin 1-7 formation in breast tissue is attenuated in breast cancer - a study on the metabolism of angiotensinogen in breast cancer cell lines.

The tissue renin-angiotensin system (RAS) plays an important role in the development and progression of many diseases. It has been confirmed that angiotensin II (ANG II) participates in the proliferation and angiogenesis of breast cancer. Moreover, some RAS dysregulations in cancer have been observed. Recent studies on the role of two opposite axes of angiotensinogen metabolism - ACE (angiotensin-converting enzyme)/ANGII/AT1R (angiotensin receptor type 1) and ACE-2/ANG 1-7/MAS (mitochondrial assembly) - indicate their importance in tumor growth and invasion, but studies describing the metabolic pathways in breast cancer and the role of newer angiotensins, such as ANG 1-12, remain lacking. In this study, the metabolism of angiotensinogen fragments in three breast cancer lines, namely, MDA-MB-231, MCF-7, and T-47D, compared with normal breast tissue cells (PCS-600) was estimated. Incubation of the cancer cells with angiotensinogen resulted in the prevalent formation of ANG 1-7. A difference in the ability to form ANG II was observed between cell lines. In normal breast cells, the strong predominance of the ACE-2/ANG 1-7/MAS pathway was detected. In cancer cells, differences in angiotensinogen metabolism depending on cancer line were observed; the prevalence of the ACE/ANG II/AT1R pathway was shown. Expressions of the RAS component were dysregulated in cancer cells and differed between cell lines. In conclusion, the ability of breast cancer cells to produce numerous angiotensin peptide metabolites was demonstrated. The metabolism of angiotensinogen differed between various types of breast cancer cells. The obtained results indicate the greater importance of the classical pathway - ACE/ANG II/AT1R - in breast cancer cells. The production of ANG 1-12 seems to be marginal in breast tissue, but a tendency for the higher formation of this peptide in cancer cells was observed. The production of ANG 1-7 was significantly lower in cancer cells, whereas the expression of MAS receptor was higher than that in the control. This finding suggests that substances with MAS receptor agonist activity could be useful in the treatment of breast cancer, but this requires further investigations.

Validation of a LC method for the determination of 5-aminosalicylic acid and its metabolite in plasma and urine.

The choice of a proper analytical method for the quantification of drugs and/or their metabolites in biological samples plays a significant role in the evaluation and interpretation of bioavailability, bioequivalence and pharmacokinetic data. The aim of this study was validation of a method for the identification and quantitative determination of 5-aminosalicylic acid (5-ASA) and its metabolite N-acetyl-5-aminosalicylic acid in human plasma and urine. According to previous studies on the disposition of 5-ASA (mesalazine) in a patient with inflammatory bowel diseases, we have developed a rapid, sensitive method for the determination of 5-ASA and its acetylated metabolite, N-acetyl-5-aminosalicylic acid (Ac-5-ASA). The advantage of this method is that it measures both compounds, and is more rapid, reproducible and credible than the previous studies [C. Fischer, K. Maier, U. Klotz, J. Chromatogr. Biomed. Appl. 225 (1981) 498-503; P.N. Shaw, A.L. Sivner, L. Aarons, J.B. Houston, J. Chromatogr. Biomed. Appl. 274 (1983) 393-397; B. Norlander, R. Gotthard, M. Strom, Aliment. Pharmacol. Ther. 3 (1989) 333-342; U. Klotz, G.L. Stracciari, Arzneim.-Forsch. Drug Res. II 43 (12) (1993) 1357-1359]. 5-ASA was quantitatively determined in human plasma and urine samples by liquid chromatography following prior derivatization to its acetylated metabolite (Ac-5-ASA). N-Acetyl-anthranilic acid was used as the internal standard. The detection was performed with a spectrofluorimetric detector, excitation at 311 nm, cut-off at 449 nm. The method was validated for the following parameters: linearity, recovery, sensitivity, precision, accuracy, selectivity and stability, limits of quantification and of detection. It showed good linearity (r2 > or = 0,996) in the range 0.1 ng/ml to 8 microg/ml using a Lichrospher 60 RP-select B column. The lower limit of detection was 20 ng/ml in plasma and urine. The within-run relative standard deviations (R.S.D.) were below 6.7% at all concentration levels and the between-run R.S.D. were below 25.4% at all concentration levels.

Significance of toxic interactions in medicolegal evidence. Complex fatal poisoning with drugs of abuse in the material of the Chair of Forensic Medicine, Collegium Medicum, Jagiellonian University in Kraków.

The subject of the study was fatal complex poisonings with drugs of abuse in two young men. In the first case, postmortem investigation revealed cardiotoxic death as the result of an interaction between opiates, amphetamine derivatives and oxazepam. In the second case, death followed the administration of amphetamine derivatives and cocaine (xenobiotics known on the illicit drug market as "UFO"). Based on the toxicological postmortem analysis the authors discuss the interpretation of the results in the light of general problems of interactions taking place in toxicokinetic and toxicodynamic phases of intoxication processes.