Pneumococcal IgA1 Protease Activity Interferes with Opsonophagocytosis of Streptococcus Pneumoniae Mediated by Serotype-Specific Human Monoclonal IgA1 Antibodies

Bacteria‐specific IgA antibodies are efficient opsonins for neutrophils and mononuclear phagocytes, provided that the phagocytes express the Fca receptor (CD89). Expression of CD89 can be stimulated by inflammatory cytokines, activated complement factors and certain microbial components. In one study, unstimulated phagocytes were able to ingest IgA antibody‐treated pneumococci, but only in the presence of complement, which was found to be activated by the IgA antibodies along the alternative pathway. Pneumococci produce IgA1 protease that cleaves human IgA1, but not IgA2, molecules in the hinge region. This leaves IgA1 as Fabα (monovalent) deprived of Fcα which contains the docking site for CD89. IgA1 is the vastly predominant subclass of IgA in the upper airways and circulation of humans.

Aims:  To examine the effects of IgA1 protease activity and complement on phagocytosis of IgA antibody‐coated pneumococci by an unstimulated human phagocytic cell line (hl60).

Materials and methods:  IgA1 and IgA2 monoclonal antibodies to serotype 4 pneumococcal capsular polysaccharide (ps) were generated by heterohybridoma technique involving B cells from human vaccinees. Isogenic serotype 4 pneumococci with and without IgA1 protease activity, respectively, were obtained after inactivation of the iga gene of the TIGR4 strain. Opsonophagocytosis was quantitated using the assay described by Romero‐Steiner et al. Based on enumeration of surviving bacteria by culture. The integrity of IgA molecules was examined by western blotting.

Results:  Both IgA1 and IgA2 antibody to type‐4 polysaccharide‐induced phagocytosis of IgA1 protease‐deficient type‐4 pneumococci equally well in the absence as in the presence of complement. Iga1 antibody to type‐4 polysaccharide displayed a fourfold higher opsonophagocytosis titer against IgA1 protease deficient compared to homologous wildtype target bacteria. A similar effect of IgA1 protease activity of the target bacteria was not observed in a parallel experiment where IgA2 antibody to type‐4 polysaccharide served as opsonin. IgA1 antibody extracted from IgA1 protease‐producing target bacteria was almost exclusively in the form of Fabα. Conversely, IgA1 from protease‐deficient bacteria and IgA2 from both types of bacteria were intact.

Conclusions:  These results indicate that the IgA1 protease activity of S. neumoniae may help the bacteria escape IgA1 antibody‐mediated opsonophagocytosis. Besides, in these experiments, IgA‐mediated opsonophagocytosis was independent of complement.

Recurrent posttraumatic meningitis due to nontypable Haemophilus influenzae: case report and review of the literature

We report a case of relapsing Haemophilus influenzae meningitis in a boy at the age of nearly 3 years and 4.2 years who had been successfully vaccinated against H. influenzae serotype b (Hib). The pathogen was a nonencapsulated (nontypable) H. influenzae strain of biotypes III and VI, respectively. A rhinobasal impalement injury with development of a posttraumatic encephalocele is considered to be the predisposing condition. Review of the literature reveals that in patients systemically infected by nonencapsulated H. influenzae strains predisposing factors such as cerebrospinal fluid-shunts, implants and traumas are often found. To obtain further information on potential new disease patterns H. influenzae isolates from cerebrospinal fluid should be examined for capsule production and, if relevant, further characterized by capsular typing.

[Demands of private gastroenterologists for collaborative treatment concepts with clinics. Results of a Germany-wide survey]

BACKGROUND

New demands and possibilities of collaboration between hospitals and private practices in Germany have appeared, now that the way has been opened legally. A poll was conducted to analyse the current status of collaboration between outpatient gastroenterologists and hospital surgical departments and to identify possible future collaborations.

MATERIALS AND METHODS

One thousand twenty-six private practices specialising in endoscopy were found by contacting the Association of Statutory Health Insurance Physicians and additional internet research. Of these, 50% were randomly selected (513 private practices) and contacted by mail with anonymous questionnaires about cooperation with their clinical partners. Two hundred three (39.6%) practices responded, of which 200 could be analysed.

RESULTS

Of all practices reached, 75% considered the cooperation with clinics very valuable or even exceptional. Still, almost half (46%) suggested necessary improvements in these collaborations. Around a third of all contacted colleagues were already involved in projects following integrated care models. In about 80% of all participants, the main interest in integrated models was specified to be common therapy planning.

CONCLUSION

The data analysis of this study shows a substantial interest of private-practice gastroenterologists in close collaboration with hospitals. It is now up to the hospitals to open contracts with their medical outpatient partners.

Two neisseria meningitidis strains with different ability to stimulate toll-like receptor 4 through the MyD88-independent pathway

Neisseria meningitidis causes acute severe diseases, including sepsis and meningitis, and more benign manifestations such as chronic meningococcemia or colonization of the upper respiratory tract. The inflammatory response, which contributes to the pathogenesis of meningococcal disease, is initiated by pattern recognition receptors, among which Toll-like receptors (TLR)s have been ascribed a particularly important role. We have previously demonstrated that N. meningitidis induce proinflammatory cytokine expression through TLR2 and TLR4. Here we characterize the molecular basis for differential activation of the inflammatory response by two N. meningitidis strains. This difference was due to differential ability to activate signal transduction through TLR4, as HEK293 cells expressing TLR4 produced significantly different levels of interleukin-8 in response to these strains. At the level of signal transduction, the two strains differed substantially in their ability to activate the pathway to nuclear factor kappaB in HEK293-TLR4/MD2 cells at late, but not early, time points. TLR4 activates two signal transduction pathways: one dependent on the adaptor molecule MyD88 and one independent of MyD88, and these pathways induce distinct patterns of gene expression in response to TLR4 ligands. By using macrophages from TLR2-/- mice, we observed that the two strains differed in their ability to activate the TLR4-induced MyD88-independent pathway, but not the MyD88-dependent pathway. This idea was further supported by experiments where either of the two pathways was inhibited and IL-8 secretion was measured. These data therefore provide molecular insight into activation of the inflammatory response by N. meningitidis, which is one of the key events in the pathogenesis of meningococcal disease.

Matrix metalloproteinase inhibitor RO 28-2653 decreases liver metastasis by reduction of MMP-2 and MMP-9 concentration in BOP-induced ductal pancreatic cancer in Syrian Hamsters: inhibition of matrix metalloproteinases in pancreatic cancer

BACKGROUND

Matrix metalloproteinases (MMP) are proteolytic enzymes which degrade the extracellular matrix and therefore play an important role in metastasis. However, the impact of MMP inhibitors (MMPI) on pancreatic cancer is still unclear. Thus we evaluated the influence of selective MMPI Ro 28-2653 on the incidence of liver metastases and the concentration of MMP-2 and MMP-9 in ductal pancreatic adenocarcinoma in Syrian hamster.

MATERIAL AND METHODS

One hundred and thirty male Syrian hamsters were randomised into 8 groups (Gr.1-3: n=15, Gr.4-8: n=17). Pancreatic cancer was induced by weekly subcutaneous injection of 10mg N-nitrosobis-2-oxopropylamin (BOP)/kg body weight (Gr.4-8) while healthy control Gr. 1-3 received 0.5 ml sodium chloride 0.9%. Gr.1 and 4 had free access to a standard diet, Gr. 2, 3 and 5-8 received a diet rich in polyunsaturated fatty acids, which increases liver metastasis in this model. In week 17 oral therapy started: Gr.3 and 6: 60 mg Eudragit/kg body weight/d (vehicle of MMPI), Gr.7 and 8: 40 mg, respectively, 120 mg RO 28-2653/kg body weight/d; Gr.1, 2, 4, 5: no therapy. After 30 weeks all hamsters were sacrificed and histopathologically examined. Additionally concentrations of MMP-2 and MMP-9 were measured in non-metastatic liver and liver metastases.

RESULTS

Concentrations of MMP-2 and MMP-9 in liver metastases were decreased by high- and low-dose therapy with MMPI. Furthermore, the incidence of liver metastases was significantly reduced by low-dose therapy with Ro 28-2653.

CONCLUSION

Low-dose therapy with Ro 28-2653 decreased liver metastasis due to an inhibition of MMP-2 and MMP-9 concentration in ductal pancreatic cancer.

Impact of polyunsaturated fatty acids on hepato-pancreatic prostaglandin and leukotriene concentration in ductal pancreatic cancer -- is there a correlation to tumour growth and liver metastasis?

Type and composition of polyunsaturated fatty acids (PUFAs) are suspected to play an important role in carcinogenesis. Thus we investigated the effects of n-3, n-6 and n-9 PUFAs on tumour growth, liver metastasis and concentration of prostaglandins (PG) and leukotrienes (LT) in experimental ductal pancreatic adenocarcinoma. Ninety male hamsters were randomised into six groups (Gr.) (n=15). While Gr. 1-3 were healthy control groups, Gr. 4-6 weekly received subcutaneous injections of 10mg N-nitrosobis-2-oxypropylamine (BOP)/kg body weight for 12 weeks in order to induce ductal pancreatic adenocarcinoma. Between week 1 and 16 all animals were fed with a standard diet with a raw fat content of 2.9%. In week 17 Gr. 1-6 were allocated to three types of diets: Gr. 1: standard high fat (=SHF diet, rich in n-6 PUFAs)/Gr. 2: FISH-OIL (rich in n-3 PUFAs)/Gr. 3: SMOF (=mixture of n-3, n-6 and n-9 PUFAs)/Gr. 4: BOP+SHF/Gr. 5: BOP+SMOF/Gr. 6: BOP+FISH-OIL. After 32 weeks all animals were sacrificed and pancreas as well as liver were analysed histologically. Furthermore pancreatic and hepatic concentrations of prostaglandins (PGF1alpha, PGE(2)) and LT were measured. FISH-OIL decreased number of macroscopically visible pancreatic tumours (Gr. 4-6: 54.5% vs. 45.5% vs. 9.1%, P<0.05) as well as incidence of liver metastasis (Gr. 4-6: 90.9% vs. 72.7% vs. 36.4%, P<0.05). Furthermore concentration of PGF(1)(alpha), PGE(2) and LT were significantly increased in pancreatic carcinoma compared to tumour-free tissue. Moreover levels of PGF(1)(alpha) and PGE(2) were higher in liver metastasis than in extrametastatic hepatic tissue. However, in Gr. 6 (FISH-OIL) intrametastatic concentration of LT was significantly lower than in non-metastatic hepatic tissue as well as in Gr. 4 and Gr. 5. FISH-OIL decreased number of visible pancreatic tumours and incidence of histological proven liver metastasis. This effect might be caused by a decrease of intrametastatic concentration of LT compared to extrametastatic hepatic tissue.

n-3, n-6, and n-9 polyunsaturated fatty acids--which composition in parenteral nutrition decreases severity of acute hemorrhagic necrotizing pancreatitis in rats?

BACKGROUND AND AIMS

Acute pancreatitis often requires parenteral nutrition. Thus, we analyzed, using a randomized trial, whether different fatty acids in parenteral nutrition influence lipidperoxidation and histopathology in acute pancreatitis in rats.

MATERIALS AND METHODS

Seventy-five male Sprague-Dawley rats were randomized into five groups (gr.) (n=15). Gr. 1 underwent a laparotomy followed by saline infusion, gr. 2-5 received intraductal glycodeoxycholic acid (GDOC) followed by intravenous cerulein. Six hours after induction of pancreatitis (IOP), gr. 2 received saline infusion, while gr. 3 was infused with standard lipovenous (rich in [n-6] polyunsaturated fatty acids (PUFA)), gr. 4 received ClinOleic (rich in [n-9] PUFA), while gr. 5 was infused with Omegaven (rich in [n-3] PUFA) for 18 h. After 24 h, all animals were sacrificed and the pancreas was determined histopathologically according to the severity of pancreatitis. Furthermore, pancreatic lipidperoxidation (TBARS) and activity of lipid production protective enzymes superoxide dismutase (SOD) and gluthationperoxidase (GSHPx) were analyzed.

RESULTS

Omegaven infusion reduced the severity of histopathologic changes in acute pancreatitis and decreased lipidperoxidation (TBARS) in pancreatic tissue samples. Furthermore, pancreatic activity of SOD was increased. However, standard PUFA and ClinOleic infusion did not influence the severity of pancreatitis and lipidperoxidation.

CONCLUSION

Parenteral nutrition high in n-3 PUFA seems to be superior to compositions of n-6 or n-9 PUFA in the treatment of acute hemorrhagic pancreatitis in rats.

Does enteral nutrition of dietary polyunsaturated fatty acids promote oxidative stress and tumour growth in ductal pancreatic cancer? Experimental trial in Syrian Hamster

BACKGROUND

Type and composition of dietary fat intake is supposed to play an important role in carcinogenesis. Thus we investigated the effects of n-3, n-6 and n-9 polyunsaturated fatty acids (PUFA) on oxidative stress (lipidperoxidation) and tumour growth in ductal pancreatic cancer.

METHODS

Ninety male hamsters were randomized into 6 groups (gr.) (n=15) and allocated to 3 main dietary categories: gr. 1 and 2 received a standard high fat diet (SHF, rich in n-6 PUFA), while gr. 3 and 4 were fed with a diet containing a mixture of n-3, n-6 and n-9 PUFA (SMOF) and gr. 5 and 6 had free access to a diet rich in n-3 PUFA (FISH-OIL). Gr. 1, 3 and 5 received weekly subcutaneous (s.c.) injections of 10 mg N-nitrosobis-2-oxypropylamine (BOP)/kg body weight in order to induce ductal pancreatic adenocarcinoma. Healthy control gr. 2, 4 and 6 were treated with 0.5 ml 0.9% sodium chloride s.c. After 32 weeks all animals were sacrificed. Removed pancreata were weighed and analysed histologically and biochemically. Activities of glutathionperoxidase (GSH-Px), superoxiddismutase (SOD) and levels of lipidperoxidation were measured in samples of pancreatic carcinoma as well as in tumour-free pancreatic tissue.

RESULTS

While different diets did not significantly alter the overall incidence of histologically proven pancreatic adenocarcinoma, the number of macroscopically visible tumours was decreased in the FISH-OIL-gr.

CONCLUSION

Different diets did not significantly influence the incidence of histologically proven pancreatic adenocarcinoma. However, administration of a diet rich in n-3 PUFA (FISH-OIL) resulted in a decrease of macroscopically visible tumours, thus indicating its beneficial effects in respect to attenuation of tumour growth.

Efficient and fast targeted production of murine models based on ENU mutagenesis

Mice with targeted genetic alterations are the most effective tools for deciphering organismal gene function. We generated an ENU-based parallel C3HeB/FeJ sperm and DNA archive characterized by a high probability to identify allelic variants of target genes as well as high efficiencies in allele retrieval and model revitalization. Our archive size of over 17,000 samples contains approximately 340,000 independent alleles (20 functional mutations per individual sample). Based on an estimated number of approximately 30,000 mouse genes, the parallel sperm/DNA archive should permit the identification and recovery of ten or more alleles per average target gene which translates to a calculated 99% success rate in the discovery of five allelic variants for any given average gene. The low rate of unrelated ENU-induced passenger mutations has no practical impact on the analysis of the allele-specific phenotype at the G3 generation because of dilution and free segregation of such unrelated passenger mutations. To date 39 mouse models representing 33 different genes have been recovered from our archive using in vitro fertilization techniques. The generation time for a murine model heterozygous for a mutation in a gene of interest is less than 2 months, i.e., three to four times faster compared with current embryonic stem-cell-based technologies. We conclude that ENU-based targeted mutagenesis is a powerful tool for the fast and high-throughput production of murine gene-specific models for biomedical research.

Influence of different dietary fat intake on liver metastasis and hepatic lipid peroxidation in BOP-induced pancreatic cancer in Syrian hamsters

OBJECTIVES

Effects of polyunsaturated fatty acids (PUFA) on carcinogenesis are discussed controversially. Thus, tumor growth seems to be influenced by type and composition of fat dietary; however, the pathomechanism is still unknown. Therefore, we investigated the impact of different PUFAs on liver metastasis and hepatic lipid peroxidation in a solid model of ductal pancreatic cancer in Syrian hamsters.

METHODS

90 male hamsters were randomized into 6 groups (n = 15). Accordingly groups 2, 4 and 6 received 10 mg N-nitrosobis-2-oxopropylamine (BOP)/kg body weight weekly by subcutaneous injection for 12 weeks in order to induce ductal pancreatic cancer, while groups 1, 3 and 5 were treated with 0.5 ml 0.9% sodium chloride. All hamsters received a standard fat diet (SFD) rich in n-6 PUFA for 16 weeks (2.9% fat). Afterwards, groups 1 and 2 had free access to SFD, while groups 3 and 4 were given a diet enriched with n-3, n-6 and n-9 PUFA (SMOF) and groups 5 and 6 were fed a diet high in n-3 PUFA (FISH-OIL). After 32 weeks all hamsters were sacrificed in order to determine incidence of pancreatic carcinoma and liver metastasis. Furthermore hepatic activities of glutathionperoxidase (GSH-Px) and superoxiddismutase (SOD) as well as levels of lipidperoxidation were analyzed intra- and extrametastatically.

RESULTS

The incidence of liver metastasis was decreased in the FISH-OIL tumor group compared to the SFD and SMOF groups. However, GSH-Px activity was not influenced by different diets. Extrametastatic hepatic SOD activity did not differ between all groups, while intrametastatic hepatic SOD activity in the SFD-BOP group was increased. In the FISH-OIL-BOP and the SMOF-BOP group intrametastatic SOD activity was lower than in non-metastatic hepatic tissue. Furthermore levels of hepatic lipid peroxidation were decreased in the tumor groups treated with fish oil and SMOF compared to the SFD group. Comparing intra- and extrametastatic TBARS concentration there was no difference in the SFD-BOP and the SMOF-BOP groups, while in the FISH-OIL-BOP group intrametastatic TBARS concentration was increased.

CONCLUSION

Conclusively, fish oil reduced the incidence of liver metastasis in experimental ductal pancreatic cancer. Maybe this effect is caused by an increase of intrametastatic hepatic lipid peroxidation.

Effects of selective COX-2 and 5-LOX inhibition on prostaglandin and leukotriene synthesis in ductal pancreatic cancer in Syrian hamster

Selective inhibition of eicosanoid synthesis seems to decrease carcinogenesis, however, the effect on liver metastasis in pancreatic cancer is still unknown. Ductal pancreatic adenocarcinoma was chemically induced by weekly injection of N-nitrosobis-2-oxopropylamine (BOP) in Syrian hamster. Animals received selective inhibition of cyclooxygenase-2 (Celebrex) and 5-lipoxygenase (Zyflo). In week 33, hamsters were sacrificed and incidence of pancreatic carcinomas as well as liver metastases were examined. Furthermore, size and number of liver metastases per animal were determined and concentration of PGF1alpha, PGE2 and leukotrienes was measured in hepatic and pancreatic tissue. Combined therapy (Celebrex+Zyflo) significantly decreased incidence, number and size of liver metastases. Furthermore extra- and intrametastatic concentration of PGE2 was reduced by this treatment in hepatic tissue. Single Cox-2-inhibition (Celebrex) decreased intrametastatic hepatic PGF1alpha and PGE2 concentration while PGF1alpha concentration was reduced in non-metastatic liver (nml). Moreover 5-LOX-inhibition (Zyflo) decreased intrametastatic PGE2 concentration as well as PGF1alpha and PGE2 in nml. In pancreatic carcinomas highest LT-concentration was found after combined treatment and this therapy group was the only one revealing a significantly higher amount of LTs in carcinomas compared to tumour-free tissue. Hepatic LT-concentration was significantly lower in the control groups than in nml of the tumour groups. Combination of Cox-2-inhibition and 5-Lox-inhibition might be a suitable adjuvant therapy to prevent liver metastasis in human ductal pancreatic adenocarcinoma.

Aerococcus urinae: polyphasic characterization of the species

A polyphasic characterization of Aerococcus urinae is presented. In this study the intraspecies relationships between 26 strains of varying geographical origin were examined by phenotypic tests, ribotyping and multilocus enzyme electrophoresis. The results demonstrated two main phenotypic patterns that could be distinguished in tests for hydrolysis of aesculin, and acid production from amygdalin and salicin. Strains were either negative (n=19) or positive (n=6) in these tests. One strain had a deviating pattern. Heterogeneity within the 19 pattern I strains was demonstrated especially by phenotypic tests (acid production from ribose, mannitol, sorbitol, sucrose and D-arabitol) and by multilocus enzyme electrophoresis. However, DNA sequence analysis of the 16S rRNA (n=7) and gyrB genes (n=3) from strains representing the two main patterns showed no variation in sequences among strains. Comparison of A. urinae and representatives of related taxa by 16S rDNA sequence analysis showed that the taxon is related to, but distinct from, other Aerococcus spp.

LapSim virtual reality laparoscopic simulator reflects clinical experience in German surgeons

BACKGROUND AND AIMS

The aim of this study was to analyze the ability of a training module on a virtual laparoscopic simulator to assess surgical experience in laparoscopy.

METHODS

One hundred and fifteen participants at the 120th annual convent of the German surgical society took part in this study. All participants were stratified into two groups, one with laparoscopic experience of less than 50 operations (group 1, n=61) and one with laparoscopic experience of more than 50 laparoscopic operations (group 2, n=54). All subjects completed a laparoscopic training module consisting of five different exercises for navigation, coordination, grasping, cutting and clipping. The time to perform each task was measured, as were the path lengths of the instruments and their respective angles representing the economy of the movements. Results between groups were compared using chi(2) or Mann-Whitney U-test.

RESULTS

Group 1 needed more time for completion of the exercises (median 424 s, range 99-1,376 s) than group 2 (median 315 s, range 168-625 s) (P<0.01). Instrument movements were less economic in group 1 with larger angular pathways, e.g. in the cutting exercise (median 352 degrees , range 104-1,628 degrees vs median 204 degrees , range 107-444 degrees , P<0.01), and longer path lengths (each instrument P<0.05).

CONCLUSION

As time for completion of exercises, instrument path lengths and angular paths are indicators of clinical experience, it can be concluded that laparoscopic skills acquired in the operating room transfer into virtual reality. A laparoscopic simulator can serve as an instrument for the assessment of experience in laparoscopic surgery.

Effects of the antioxidative vitamins A, C and E on liver metastasis and intrametastatic lipid peroxidation in BOP-induced pancreatic cancer in Syrian hamsters

BACKGROUND/AIMS

Antioxidative vitamins are known to inhibit metastasis. Therefore we evaluated the impact of vitamins A (retinol), C (ascorbic acid) and E (alpha-tocopherol) on liver metastasis in a model of ductal pancreatic adenocarcinoma in hamster.

METHODS

One hundred and twenty male Syrian hamsters were randomized into 8 groups (Gr.) (n = 15). Gr. 1-4 were given 0.5 ml normal saline subcutaneously (s.c.) weekly, whereas Gr. 5-8 received 10 mg N-nitrosobis(2-oxopropyl)amine (BOP)/kg body weight s.c. for 3 months for tumor induction. In the 13th week Gr. 2 and 6 were administered retinol, Gr. 3 and 7 received ascorbic acid and Gr. 4 and 8 were given alpha-tocopherol orally. No treatment was performed in Gr. 1 and 5. After 24 weeks animals were sacrificed, pancreas and liver were histologically determined. Activities of glutathione-peroxidase (GSH-Px), superoxide dismutase (SOD) and concentration of thiobarbituric-acid-reactive substances (TBARS) were analyzed in hepatic tissue.

RESULTS

Retinol and alpha-tocopherol decreased the incidence of liver metastases (44.4 vs. 86.7%, p < 0.05). The number and size of liver metastases were significantly reduced by retinol. Activities of GSH-Px and SOD were increased and concentration of TBARS was decreased in NML and LiMe by all vitamins.

CONCLUSION

Obviously, antioxidative vitamins prevent oxidative stress in hepatocytes. This may be one mechanism decreasing liver metastasis in pancreatic cancer in the present trial.

Morphology of the rat peritoneum after carbon dioxide and helium pneumoperitoneum: a scanning electron microscopic study

BACKGROUND

Laparoscopic surgery for patients with cancer has been debated because of the susceptibility that laparoscopic incisions have shown for metastatic tumor growth. Structural damage of the mesothelial layer attributable to the pneumoperitoneum may facilitate intraabdominal tumor cell adhesion and growth. The influence of carbon dioxide (CO(2)) and helium pneumoperitoneum on the morphology of the peritoneum was examined.

METHODS

A total of 50 rats received colon carcinoma (DHB/TRb) cells intraperitoneally and CO(2) (n = 25) or helium (n = 25) pneumoperitoneum at 15 mmHg for 15 min. After different periods (2, 12, 24, 48, and 96 h), the rats were killed, and the peritoneum was examined by scanning electron microscopy. Control animals (n = 5) were without pneumoperitoneum.

RESULTS

The control animals and most of the rats with pneumoperitoneum showed no peritoneal alterations. In four animals of each group, inflammatory alterations of the peritoneum such as bulging and retraction of mesothelial cells were observed at different time points. Tumor cells adherent to the peritoneum were found in a total of six animals. Peritoneal carcinomatosis, tumor nodules, or infiltration of the peritoneum by tumor cells was not observed.

CONCLUSIONS

The study demonstrated that the morphologic integrity of the rat peritoneum is not disturbed when CO(2) or helium is used for insufflation combined with the intraperitoneal injection of carcinoma cells. Pneumoperitoneum therefore probably is not the condition causing peritoneal changes that favor intraperitoneal tumor growth.

Ciprofloxacin susceptibility of Pseudomonas aeruginosa isolates from keratitis

AIM

To examine the ciprofloxacin susceptibility of 106 Pseudomonas aeruginosa eye isolates from the United Kingdom, Denmark, India, the United States, and Australia, and to determine the molecular mechanisms of resistance.

METHODS

Ciprofloxacin susceptibility was tested by an agar dilution method; genomic DNA corresponding to the quinolone target genes gyrA and parC, and the regulatory genes mexR and nfxB controlling drug efflux systems, was amplified by PCR and sequenced; multilocus enzyme electrophoresis was performed to examine the genetic relation among resistant strains.

RESULTS

Three out of 90 keratitis isolates (3.3%), one from the United Kingdom and two from India, exhibited MIC values of 16 mg/l or 32 mg/l. The UK isolate had a mutation in gyrA (Thr83Ile), whereas the two Indian isolates showed mutations in both gyrA (Thr83Ile) and parC (Ser87Leu). The remaining isolates from keratitis, endophthalmitis, contact lens associated red eye (CLARE), and contact lens storage cases showed MIC values below 1 mg/l. Several allelic forms of gyrA and a single variation in the mexR gene product were detected in 10 ciprofloxacin susceptible strains.

CONCLUSIONS

The vast majority of eye isolates of P aeruginosa from European countries are fully susceptible to ciprofloxacin and the concentration of ciprofloxacin eye drops used for local treatment (3000 mg/l) exceeds MIC values for strains recorded as resistant. Mutations in more than one target gene were associated with higher MIC values.

Effects of taurolidine and octreotide on tumor growth and lipid peroxidation after staging-laparoscopy in ductal pancreatic cancer

Irrigation with taurolidine after laparoscopy decreases tumor growth in colon carcinoma. In pancreatic cancer subcutaneous therapy with octreotide decreases oxidative stress and carcinogenesis as well. However, it is still unclear, whether irrigation with taurolidine or octreotide after laparoscopic pancreatic biopsy reduces tumor growth in pancreatic cancer as well. In 60 Syrian hamsters ductal pancreatic adenocarcinoma was induced by weekly injection of 10mg/kg body weight N-nitrosobis-2-oxopropylamine s.c. for 10 weeks. In week 16 laparoscopic pancreatic biopsy by use of carbon dioxide was performed (gr. 1, n = 20) with subsequent laparoscopic irrigation with taurolidine (gr. 2, n = 20) or octreotide (gr. 3, n = 20). In week 25 hamsters were sacrificed. Our results show that macroscopic visible primary tumors were found in only one animal of the taurolidine group (5.9%), compared to 42.1% in the saline and 62.5% in the octreotide group (P<0.05). Carcinomas were smaller after saline (6+/-23 mm(2)) than after octreotide irrigation (70+/-120 mm(2), P<0.05). In conclusion this study showed that laparoscopic irrigation with taurolidine after pancreatic biopsy inhibited tumor growth in ductal pancreatic adenocarcinoma.

Influence of conjugated and conventional linoleic acid on tumor growth and lipid peroxidation in pancreatic adenocarcinoma in hamster

Conventional linoleic acid (LA) is regarded as a promotor of carcinogenesis. However, the effect of its conjugated derivative on cancer is still unknown. Therefore we investigated the influence of conventional and conjugated LA on tumor growth and lipid peroxidation in a solid model of pancreatic adenocarcinoma in Syrian hamsters. 60 male hamsters were randomized in 4 groups (Gr.) (n=15). Gr. 1 and 2 received 0.5 ml 0.9% sodium chloride subcutaneously (s.c.) once a week while Gr. 3 and 4 were injected 10 mg N-nitrosobis-2-oxopropylamine (BOP)/kg body weight weekly for 12 weeks to induce pancreatic cancer. Gr. 1 and 3 received a diet containing conventional LA, Gr. 2 and 4 were fed a diet of conjugated LA. After 29 weeks all animals were sacrificed, pancreas was weighed and examined macroscopically and histologically. The level of lipid peroxidation and activities of glutathion peroxidase and superoxide dismutase were determined in tumor-free as well as in pancreatic carcinoma tissue. Different diets did not influence the incidence of pancreatic carcinoma, however, pancreas weight was increased by conjugated LA compared to conventional LA. Furthermore both diets decreased the activity of glutathion peroxidase and increased the level of lipid peroxidation in pancreatic intratumoral tissue. The content of conjugated LA in dietary did not influence pancreatic tumor growth in a solid model of pancreatic adenocarcinoma in Syrian hamsters.

Effects of Celebrex and Zyflo on liver metastasis and lipidperoxidation in pancreatic cancer in Syrian hamsters

Selective inhibition of eicosanoid synthesis is thought to have effects on carcinogenesis in lung and colon cancer. However, it is still unknown whether pancreatic cancer might also be influenced. Therefore we evaluated the impact of selective cyclooxygenase-2 inhibitor Celebrex and selective 5-lipoxygenase inhibitor Zyflo on liver metastasis in a solid model of pancreatic adenocarcinoma in Syrian hamster. In week 33, the animals were sacrificed and incidence of pancreatic carcinomas and number and size of liver metastases were determined. Activities of antioxidative enzymes (GSHPX/SOD) and concentrations of products of lipidperoxidation were measured in liver metastases and non-metastatic hepatic tissue. The incidence (54.5 vs. 100%), number (3.17 +/- 0.98 vs. 6.75 +/- 0.71) and size (2.67 +/- 1.97 vs. 11.75 +/- 1.98 mm2) of liver metastases were decreased by combined therapy of Zyflo and Celebrex (P < 0.05). Furthermore, activities of GSHPX ([73.77 +/- 5.67]*10(5) vs. [15.49 +/- 4.02]*10(5) U/mg prot.; P < 0.05) and SOD (474.92 +/- 108.8 vs. 127.89 +/- 38.75 U/mg prot.; P < 0.05) were increased, while lipidperoxidation (0.31 +/- 0.08 nmol/mg prot. vs. 1.54 +/- 0.55 nmol/mg prot.; P < 0.05) was decreased by combination therapy, in non-metastatic hepatic tissue. Moreover, combined therapy increased lipidperoxidation in liver metastases (0.47 +/- 0.09 vs. 1.95 +/- 0.12 nmol/mg prot.; P < 0.05). Thus, a combination of Celebrex and Zyflo might be a new concept to decrease tumour growth in liver metastases in advanced pancreatic cancer.

Different bacteriocin activities of Streptococcus mutans reflect distinct phylogenetic lineages

Bacteriocins produced by mutans streptococci are known as mutacins. In this study 16 broadly active mutacin-producing Streptococcus mutans strains from New Zealand, North America and Europe were classified into four groups (A-D) on the basis of differences in their activity in deferred antagonism tests against either the homologous producer strain (to test for presence of self-immunity) or indicator strains Staphylococcus aureus 46 and Enterococcus faecium TE1. Two of the strains included in the study (UA140 and UA96) were representatives of the group I and II mutacin producer strains previously described by Caufield and co-workers. One of the New Zealand isolates of group A (S. mutans strain N) appeared to produce inhibitory activity similar to that of the group I prototype strain UA140. Four other New Zealand isolates of group B (S. mutans strains M19, M34, B34 and D14) had mutacin II-like activity. The group B mutacin producers differed from the group A mutacin producers in their additional activity against Staph. aureus 46. Seven S. mutans strains (M46, B46, B57, M12, M28, B28 and 13M) were distinguished from the group A and group B mutacin producers in that they inhibited E. faecium TE1. These were called group C mutacin producers. Strains H7 and H23 resembled the group C strains in their action on both indicator strains TE1 and 46. However, these two strains failed to exhibit immunity to their own inhibitory products in the deferred antagonism test and were separately classified as group D mutacin producers. Phylogenetic analysis of the strains by several genotypic and phenotypic characteristics revealed that the mutacin groups were associated with distinct evolutionary lineages of S. mutans.

Influence of conjugated vs. conventional linoleic acid on liver metastasis and hepatic lipidperoxidation in BOP-induced pancreatic cancer in Syrian hamster

While conjugated linoleic acid (CLA) is regarded as an essential fatty acid with anticarcinogenic effects, conventional linoleic acid (LA) is reported to promote tumour growth in various experimental studies probably caused by high sensitivity to non-enzymatic lipid peroxidation. In order to evaluate the impact of dietary LA and CLA on liver metastasis and lipidperoxidation (LPO), 60 Syrian hamsters were injected with 10 mg N -nitrosobis-2-oxopropylamine (BOP)/kg body weight s.c. for 12 weeks. Animals were fed a special diet containing LA or CLA. The experiment was terminated after 24 weeks. Incidence, number and size of liver metastases were histologically determined. Furthermore, the activities of antioxidative enzymes and concentration of hepatic lipidperoxidation were measured intra- and extrametastatically. Incidence, number and size of liver metastases did not differ between the tumour groups. Otherwise, antioxidative enzyme activity of GSH-Px was higher in non-metastatic liver, while SOD activity and lipidperoxidation were increased in liver metastases. Conclusively there was no difference between the groups fed with LA and CLA according to the impact on liver metastasis in ductal pancreatic cancer.

Establishment of streptococci in the upper respiratory tract: longitudinal changes in the mouth and nasopharynx up to 2 years of age

As part of a series of longitudinal studies on the development of the indigenous microflora of the upper respiratory tract, the establishment of streptococci in the oral cavity and nasopharynx and IgA1 protease production by the early streptococcal flora was examined in 50 healthy Caucasian infants at the ages of 2, 6, 12, 18 and 24 months. In the oral cavity, streptococci were found in all infants on every sampling occasion, Streptococcus mitis biovar 1 being the main finding in each age group. S. salivarius and S. mitis biovar 2 reached their highest prevalence during the first year of life, whereas the prevalence of S. oralis and S. sanguis showed no significant increase before 12 months of age. Salivary streptococci mainly consisted of the above-mentioned species during the follow-up period. In contrast to the oral cavity, no stable colonisation pattern was observed for viridans streptococci in the nasopharynx. S. mitis biovar 1 and S. pneumoniae, a traditional respiratory pathogen, were the principal streptococcal species among nasopharyngeal isolates. IgA1 protease production by early streptococci was common in infancy. Among the oral streptococcal microflora, S. mitis biovar 1 (especially during the first year of life) and S. oralis and S. sanguis constituted the main species responsible for this enzyme activity. In the nasopharynx, IgA1 protease was produced by S. mitis biovar 1, S. oralis and S. pneumoniae. In conclusion, streptococcal colonisation differs in these two close habitats in the upper respiratory tract.