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J Ries

Publications and source records attributed to J Ries.

At least 19 recordsLinked to original sources
PubMed2006

Mobility of Min-proteins in Escherichia coli measured by fluorescence correlation spectroscopy.

In the bacterium Escherichia coli, selection of the division site involves pole-to-pole oscillations of the proteins MinD and MinE. Different oscillation mechanisms based on cooperative effects between Min-proteins and on the exchange of Min-proteins between the cytoplasm and the cytoplasmic membrane have been proposed. The parameters characterizing the dynamics of the Min-proteins in vivo are not known. It has therefore been difficult to compare the models quantitatively with experiments. Here, we present in vivo measurements of the mobility of MinD and MinE using fluorescence correlation spectroscopy. Two distinct timescales are clearly visible in the correlation curves. While the faster timescale can be attributed to cytoplasmic diffusion, the slower timescale could result from diffusion of membrane-bound proteins or from protein exchange between the cytoplasm and the membrane. We determine the diffusion constant of cytoplasmic MinD to be approximately 16 microm(2) s(-1), while for MinE we find about 10 microm(2) s(-1), independently of the processes responsible for the slower time-scale. The implications of the measured values for the oscillation mechanism are discussed.

Adenosine Triphosphatases↗
PubMed2006

Plasminogen activator inhibitor-1 polymorphism is associated with increased risk for oral cancer.

In light of the recently observed contribution of thrombosis-related factors to carcinogenesis, we investigated the possible association of plasminogen activator inhibitor-1 (PAI-1) with increased risk for oral cancer. In DNA samples of 104 patients with oral squamous cell carcinoma and 106 healthy controls of comparable ethnicity, age and sex, we studied the 4G/5G polymorphism in the PAI-1 gene, which affects its expression. The mutant 4G allele and carrier frequencies were significantly increased in patients compared to controls (65.9% versus 49.5%; 88.5% versus 69.8% respectively, P<0.01). That increase was even higher in patients with a positive family history for thrombophilia or without one for cancer (P<0.001). Interestingly, significant difference from controls was observed only in patients with cancer stages I and II. These findings suggest that the 4G allele, by resulting in higher PAI-1 expression, is a major contributing factor in early stages of oral oncogenesis. Possibly, increased PAI-1 promotes initial development of oral cancer through regulation of cell detachment and delays further tumor progression by inhibiting vascularization.

Adult↗
PubMed2006

A pneumococcal pilus influences virulence and host inflammatory responses.

Streptococcus pneumoniae (pneumococcus) is a major cause of morbidity and mortality world-wide. The initial event in invasive pneumococcal disease is the attachment of encapsulated pneumococci to epithelial cells in the upper respiratory tract. This work provides evidence that initial bacterial adhesion and subsequent ability to cause invasive disease is enhanced by pili, long organelles able to extend beyond the polysaccharide capsule, previously unknown to exist in pneumococci. These adhesive pili-like appendages are encoded by the pneumococcal rlrA islet, present in some, but not all, clinical isolates. Introduction of the rlrA islet into an encapsulated rlrA-negative isolate allowed pilus expression, enhanced adherence to lung epithelial cells, and provided a competitive advantage upon mixed intranasal challenge of mice. Furthermore, a pilus-expressing rlrA islet-positive clinical isolate was more virulent than a nonpiliated deletion mutant, and it out-competed the mutant in murine models of colonization, pneumonia, and bacteremia. Additionally, piliated pneumococci evoked a higher TNF response during systemic infection, compared with nonpiliated derivatives, suggesting that pneumococcal pili not only contribute to adherence and virulence but also stimulate the host inflammatory response.

Animals↗
PubMed2006

Endocarditis and pericarditis complicating pneumococcal bacteraemia, with special reference to the adhesive abilities of pneumococci: results from a prospective study.

The incidence of pneumococcal cardiac infections is unknown and the pathogenicity of such complications is poorly understood. In a prospective, international, observational study, eight of 844 patients hospitalised with Streptococcus pneumoniae bacteraemia developed endocarditis (n = 5) or pericarditis (n = 3). The clinical and microbiological characteristics of these patients were compared with those of control patients. The corresponding incidence of pneumococcal endocarditis was c. 1-3/1 million inhabitants/year. There was no common pattern in the medical history of patients with an infectious cardiac complication. The severity of illness upon admission was comparable with that for patients without infectious cardiac complications, as was the 14-day mortality rate (25% and 17%, respectively). For encapsulated S. pneumoniae, no significant differences were found between patients with infectious cardiac complications and controls in adherence assays. However, non-encapsulated S. pneumoniae showed higher hydrophobicity and increased adherence to human epithelial cells.

Adolescent↗
PubMed2005

Methylenetetrahydrofolate reductase polymorphism and minor increase of risk for oral cancer.

PURPOSE: We investigated whether the mutant methylenetetrahydrofolate reductase (MTHFR) increases risk for oral cancer. The common germ-line mutation C677T in the MTHFR gene significantly diminishes specific activity of the enzyme, which is responsible for the circulating form of folate. Folate deficiency is associated with increased risk for thrombosis, as well as for several types of cancer, through disruption of DNA methylation, DNA synthesis and deficient DNA repair. METHODS: We searched for the C677T mutation by restriction fragment analysis of PCR products in DNA samples of 110 patients with oral squamous cell carcinoma and 120 healthy controls of comparable ethnicity, age and sex. RESULTS: The number of heterozygotes was significantly different in the two groups (P<0.005), as well as in subgroups of patients with or without a positive family history for cancer, compared to normal controls (P<0.01 and P<0.005, respectively). Furthermore, the subgroup of patients with a positive family history for thrombophilia had a significant increase both in the frequencies of mutant alleles (P<0.01) and heterozygotes (P<0.001) in comparison to normal controls. CONCLUSIONS: The obtained results suggest that the MTHFR mutation is a minor contributing factor in oncogenesis in the oral region, in conjunction with low dietary uptake of folate.

Adult↗
PubMed2004

[Conception and first results of the Spiron cementless femoral neck screw prosthesis].

The Spiron cementless femoral neck prosthesis is based on the idea of proximal force transmission. The concept of osseous anchorages has been proven successful various times. The prosthesis is a conical, self-cutting screw that is inserted without cement into the prepared subcapital implant bearing. It is produced from a corundum blasted titanium-vanadium alloy and is covered with a second-generation calcium phosphate coating. The coating and the form of the thread increase the implant's surface and help to optimize osseointegration. From February 2003 to April 2003, 38 Spiron prostheses were implanted at the DRK hospital in Neuwied (Germany) in 34 patients. Four patients received it for the replacement of both hip joints. The average age of the patients was 60.1 years at the time of the implantation (43-73 years); 20 male and 14 female patients received the prosthesis. We implanted 19 left-sided and 19 right-sided arthroplasties. The preoperative Harris hip score (HHS) was 51 (24-76), n=38. After 1 year, HHS(1) was 94 (86-100), n=20 (of 23 implants). Until now, we have not discovered any prosthesis-specific complications; the rehabilitation time shows a tendency to be shorter than after stem arthroplasty. Revision was necessary in one case because of an early infection. After 3 months, the radiological follow-up examinations showed the development of increasing trabecular reinforcement of the femoral neck and pertrochanteric regions. Until now, there is no evidence of any varus tendency of the Spiron prosthesis.

Adult↗
PubMed2004

In vitro cultured autologous pre-confluent oral keratinocytes for experimental prefabrication of oral mucosa.

The reconstruction of large defects after head and neck cancer resection often requires composite tissue transfer to replace a combination of bone, muscle and mucosa. Thus, tissue engineering techniques may be useful for oral mucosal reconstructive surgery to prefabricate mucosal tissue on the muscle flap in vivo, instead of using conventional skin-bearing composite flaps. The aim of this study was to investigate whether autogenous pre-confluent oral keratinocytes (PCOK) cultured in vitro can create mucosal coverage on muscle in vivo, in a single grafting procedure. In 30 Wistar rats, with a small piece of oral mucosa (2 mm x 5 mm), oral keratinocytes were isolated and then seeded on a hydrophilic PTFE membrane (n = 50) in serum-free culture condition. After 48 h, the membrane, together with the PCOK, was transplanted onto the gracilis muscle to fabricate a mucosal flap in vivo. The wound bed was closed primarily until the time of examination. Biopsies were carried out 1, 2, 3, and 4 weeks, respectively, after transplantation and were evaluated immunohistochemically (AE1/AE3 anti-pancytokeratin, cytokeratin 5/6, collagen IV, laminin, lectin-specific labeling of N-acetylglucosamine oligomeres of endothelial cells) with relation to the following criteria: (1) graft acceptance; (2) inflammatory signs; (3) structural changes and keratinocyte lining; (4) expression of basement membrane components; and (5) vascularization. Ninety-one percent of the grafts showed uniform epithelial layers. The mean number of reconstructed epithelial cell layers was 1.7, 2.0, 1.85 and 2.7 at 1, 2, 3 and 4 weeks, respectively after transplantation (P = 0.342). Collagen IV, laminin and lectin-specific capillaries developed between the neoepithelium and the underlying muscular layer. Only two specimens showed signs of infection 2 weeks after transplantation. In conclusion, this experiment demonstrated that PCOK grafts on muscle in vivo can achieve uniform multi-layered oral epithelial coverage in a short period of time. This technique may be a useful alternative tool for oropharyngeal reconstructive surgery and is also worth considering for further clinical studies.

Acetylglucosamine↗
PubMed2003

[In vitro effect of taurolidine on squamous cell carcinoma in the oral cavity].

Taurolidine (Taurolin) is a derivative of the amino acid taurine, successfully used in the treatment of peritonitis. In vitro and in vivo studies have shown that taurolidine inhibits cell proliferation and induces apoptosis in a variety of tumor cell lines. At present there are no published studies on the use of taurolidine in the treatment of squamous cell carcinoma. Our aim was to examine the inhibition of cell proliferation and induction of apoptosis in cell lines SCC 4 and SCC 15 treated with taurolidine in concentrations of 0.01%, 0.1%, and 0.5%. Analogue to the present investigations on adenocarcinoma cell lines, we used toxic antiseptic povidone iodine in the same concentration as for the reference group. Untreated cells were used as a control group. The cells were incubated with taurolidine or povidone iodine once for 2 h at 37 degrees C in 5% CO(2). Cell proliferation was assessed using WST-1 labeling kit after 3, 24, 48, 72, and 96 h. The additional measurement of cell apoptosis was examined using ELISA(PLUS) cell death detection kit and performed after 0, 24, and 48 h. The findings showed a significant inhibition of cell proliferation and induction of apoptosis in taurolidine-treated cells SCC 4 and SCC 15 in contrast to the reference group treated with povidone iodine or the untreated control group.

Antineoplastic Agents↗
PubMed2003

Bone regeneration in critical size defects by cell-mediated BMP-2 gene transfer: a comparison of adenoviral vectors and liposomes.

Large bone defects resulting from nonunion fractures or tumour resections are common clinical problems. Recent studies have shown bone morphogenetic protein-2 (BMP-2) gene transfer using adenoviral vectors to be a promising new therapeutic approach. However, comparative studies of different vectors are required to identify the optimal system for possible clinical trials. This study compares the use of liposome-mediated and adenoviral gene transfer for the generation of autologous BMP-2-producing bone marrow stromal cells (BMSC). Primary BMSC isolated from the rat femur were treated ex vivo with either an adenovirus or a liposome carrying human BMP-2 cDNA. The genetically modified cells were evaluated in vitro and transplanted into critical size defects in the rat mandible in vivo. BMSC treated with a reporter gene vector or untreated BMSC served as controls. The newly formed tissue was analysed by in situ hybridization, radiography and immunohistochemistry. Both groups of genetically modified cells produced BMP-2 for at least 2 weeks, and markers of new bone matrix such as osteopontin and osteocalcin were observed within 2 weeks following gene transfer. In the liposome group, the critical size defects were found completely healed at 6 weeks after the gene transfer, whereas the more efficient adenoviral gene transfer allowed for complete bone healing within 4 weeks. None of the three control groups showed bone healing, not even after 8 weeks. Thus, both liposome-mediated and adenoviral BMP-2 gene transfer to primary BMSC are suitable methods to achieve the healing of critical size bone defects in rats. As liposomes have proven sufficient for this purpose and offer several advantages over any other vector, such as ease of preparation, theoretically no limitation of the size of the DNA, and less immunological and safety problems, they may represent the best vector system for future clinical trials of bone regeneration by BMP-2 gene therapy.

Adenoviridae↗
PubMed2003

Loss of 9p21 is embedded in a complex but consistent pattern of genomic imbalances in oral squamous cell carcinomas.

35 oral squamous cell carcinomas examined previously by comparative genomic hybridization (CGH) exhibited 5 up to 47 copy number alterations (CNAs). 13 of those cases showed a loss of parts of the short arm of chromosome 9, band p21 being affected in all of these cases. A highly complex but strikingly consistent pattern of genomic imbalances with an average 31.5 CNAs per tumor was associated with this deletion, and gains clearly dominated over losses of genomic material. Comparable patterns, however, could also be found in tumors with a high number of CNAs (24 CNAs) but without the deletion. Low numbers of imbalances were accompanied by low consistency of the CNA patterns. None of these latter cases showed the deletion 9p21. 66.7% of the dim(9p21)-positive tumors were of class pT4 (vs. 22% in dim(9p21)-negative cases), 77% of stage III or IV (vs. 47% in the group without the deletion), but only 8% of the dim(9p21)-positive tumors were classified as grade 3 (vs. 41% in the negative group). Other clinicopathologic features like prevalence of relapse, or survival time could not be as clearly associated with the deletion. For instance, short relapse-free survival was clearly associated with a high number of CNAs, rather independent of presence or absence of dim(9p21) in the affected tumor. From these findings it is concluded that previously found associations of 9p21 deletion with clinical parameters can reasonably be estimated only in the context of the pattern and complexity of the genomic imbalances accompanying this chromosomal loss in the examined tumors.

Adult↗
PubMed2001

A polyketide synthase in glycopeptide biosynthesis: the biosynthesis of the non-proteinogenic amino acid (S)-3,5-dihydroxyphenylglycine.

Balhimycin, a vancomycin-type antibiotic from Amycolatopsis mediterranei, contains the unusual amino acid (S)-3,5-dihydroxyphenylglycine (Dpg), with an acetate-derived carbon backbone. After sequence analysis of the biosynthetic gene cluster, one gene, dpgA, for a predicted polyketide synthase (PKS) was identified, sharing 20-30% identity with plant chalcone synthases. Inactivation of dpgA resulted in loss of balhimycin production, and restoration was achieved by supplementation with 3,5-dihydroxyphenylacetic acid, which is both a possible product of a PKS reaction and a likely precursor of Dpg. Enzyme assays with the protein expressed in Streptomyces lividans showed that this PKS uses only malonyl-CoA as substrate to synthesize 3,5-dihydroxyphenylacetic acid. The PKS gene is organized in an operon-like structure with three downstream genes that are similar to enoyl-CoA-hydratase genes and a dehydrogenase gene. The heterologous co-expression of all four genes led to accumulation of 3,5-dihydroxyphenylglyoxylic acid. Therefore, we now propose a reaction sequence. The final step in the pathway to Dpg is a transamination. A predicted transaminase gene was inactivated, resulting in abolished antibiotic production and accumulation of 3,5-dihydroxyphenylglyoxylic acid. Interestingly, restoration was only possible by simultaneous supplementation with (S)-3,5-dihydroxyphenylglycine and (S)-4-hydroxyphenylglycine, indicating that the transaminase is essential for the formation of both amino acids.

Amino Acids↗
PubMed2001

A prospective, randomized comparison of the use versus non-use of topical corticosteroids after laser in situ keratomileusis.

OBJECTIVE: To evaluate the benefit and safety of topical corticosteroids after laser in situ keratomileusis (LASIK). DESIGN: Prospective, randomized, double-masked clinical trial. PARTICIPANTS: A consecutive series of 1747 eyes in 897 patients desiring surgical correction of myopia from plano to -16 diopters (D) with up to 6 D of astigmatism. INTERVENTION: Patients were randomly assigned to topical corticosteroids or artificial tears. MAIN OUTCOME MEASURES: The primary outcome measure was stability of refraction. Secondary outcome measures were differences in best-corrected visual acuity, decrease in spherical refractive myopia, improvement in uncorrected visual acuity, predictability of achieved corrections versus planned corrections, evaluation of postoperative haze, preservation of best-corrected visual acuity, intraocular pressure, and incidence of complications and adverse events. RESULTS: No difference was found between the groups for refractive accuracy, best-corrected or uncorrected visual acuity, or safety. Topical corticosteroids were associated with a prolonged period of refractive regression in moderate to high myopes (-7.25 to -16.00 D) (P = 0.01). Increased haze was noted at the 1 week examination for eyes not receiving topical steroids (P = 0.008); however, in most cases this was clinically insignificant. Thirty-six eyes (2.1%) required supplemental topical corticosteroids unrelated to reoperation. Two eyes received these on the first postoperative day and 15 at the 1-week examination. CONCLUSIONS: Topical corticosteroids did not seem to play any beneficial role in routine postoperative treatment after LASIK, and they were associated with decreased stability of refraction in more highly myopic eyes. Eyes that require additional topical corticosteroids are easily identified at either the initial postoperative examinations or during the course of routine postoperative care.

Administration, Topical↗
PubMed2001

Diagnostic and prognostic relevance of expression of human telomerase subunits in oral cancer.

Telomerase activity (TA) is associated with most malignant human tumors but is not detected in normal somatic cells with a few exceptions. Three major subunits (hTR, hTP1 and hTERT) of telomerase have been identified. To investigate the clinical implications of the mRNA detection of these components as useful diagnostic and prognostic markers in oral cancer, we examined TA, hTR, hTP1 and hTERT mRNA expressions in 46 oral squamous cell carcinomas (OSCC) and 15 normal oral mucosal tissues from healthy volunteers using a highly sensitive TRAP assay and RT PCR. In all specimens hTR and hTP1 mRNA were detected regardless whether TA was expressed or not. On the contrary, a significant correlation between hTERT expression and TA was shown indicating that the activity of telomerase could be regulated by the extent of hTERT transcription. In addition, hTERT expression showed close association to malignancies. None of the normal mucosal specimens expressed the hTERT subunit, but 76% (35/46) of the tumor specimens did. None of other clinico-pathological and prognostic parameters showed significant relationship with TA or hTERT expression. These results suggest that the detection of hTERT expression may be another useful diagnostic marker, especially for early detection of OSCC, and for distinguishing healthy tissues from neoplastically transformed ones.

Carcinoma, Squamous Cell↗
PubMed2000

Induction of apoptosis using 2',2' difluorodeoxycytidine (gemcitabine) in combination with antimetabolites or anthracyclines on malignant lymphatic and myeloid cells. Antagonism or synergism depends on incubation schedule and origin of neoplastic cells.

Induction of apoptosis in vitro using gemcitabine (dFdC) in combination with cladribine (2-CdA) and other cytotoxic drugs on malignant mononuclear cells (MNCs) of patients with acute myeloid leukemia (AML, n=20) and chronic lymphocytic leukemia (CLL, n =20) in myeloid (HL60, HEL) and lymphatic cell lines (HUT78, JURKAT) was investigated using different incubation conditions (simultaneous and consecutive). Furthermore, the influence of dFdC on the level of intracellular metabolites of 2-CdA was studied using high-performance liquid chromatography (HPLC). Apoptosis was evaluated using flow cytometry with 7-aminoactinomycin D. In MNCs of patients with CLL, dFdC + 2-CdA showed an antagonistic effect when applied simultaneously. This antagonism was reduced by consecutive application. The combination of dFdC with doxorubicin was synergistic, independent of incubation schedule. In blasts from newly diagnosed patients with de novo AML, all drug combinations (dFdC+2-CdA, doxorubicin, or cytosine arabinoside) were antagonistic by simultaneous incubation. Reduced antagonism or even synergism was shown (P<0.001) by consecutive incubation. The simultaneous combination of dFdC with 2-CdA in all tested cell lines resulted in a competitive inhibition on the rate of apoptosis. By changing the incubation period to a consecutive schedule, the antagonism was diminished or synergism of apoptosis was measured (P< 0.001). Using similar incubation conditions, these experiments were supported by HPLC measurement of intracellular metabolites of 2-CdA influenced by dFdC application. In conclusion, we demonstrated that the efficacy of dFdC in vitro in combination with other cytotoxic drugs depends on the incubation condition and on the origin of neoplastic cells (lymphatic vs myeloid). The data suggest that simultaneous combination therapy with purine and pyrimidine analogues may not improve the clinical efficacy of one or the other drug administered alone.

Anthracyclines↗
PubMed2000

Induction of apoptosis by 2-chloro-2'deoxyadenosine (2-CdA) alone and in combination with other cytotoxic drugs: synergistic effects on normal and neoplastic lymphocytes by addition of doxorubicin and mitoxantrone.

2-CdA is active as a single agent in the treatment of low-grade lymphomas. We analyzed the induction of apoptosis by 2-CdA alone (n=5) and in combination with other drugs in peripheral lymphocytes from 25 patients with leukemic low-grade lymphomas and from 25 healthy volunteers. 2-CdA was tested in 4 escalating concentrations (0.05 microg/ml to 0.4 microg/ml). Linear regressions showed a dose dependent apoptosis rate of 0.29 x microg 2-CdA/ml + 0.11 (r2=0.88, p=0.006) in normal cells and 0.41 x microg 2-CdA/ml + 0.15 (r2=0.88, p=0.005) in leukemic cells. Intracellular metabolization of 2-CdA into 2-CdA-5'mono-, -di- and the active metabolite -triphosphate was analyzed by HPLC and paralleled the dose dependent increase of apoptosis. The combination of 2-CdA with doxorubicin or mitoxantrone had a synergistic effect on the induction of apoptosis (p<0.001) in both normal and neoplastic lymphocytes, whereas 2-CdA plus etoposide or cytosine arabinoside were only additive. Due to the flat slope of the dose response of 2-CdA concentration on apoptosis we assume that higher in vivo dosages of 2-CdA in the treatment of low-grade lymphomas may not result in a higher clinical efficacy. The synergistic lymphocytotoxic effect of 2-CdA combined with doxorubicin or mitoxantrone may be relevant for new treatment approaches.

2-Chloroadenosine↗
PubMed1999

Superoxide: a major factor for stress protein induction in reoxygenation injury in the intestinal cell line Caco-2.

BACKGROUND/AIMS: Acute intestinal ischemia is followed by cellular destruction and loss of mucosal barrier function. Posthypoxic injury of cellular proteins leads to the synthesis of heat shock proteins. The role of oxygen radicals in this process, however, is not fully established. METHODS: In the present study, using the intestinal cell line Caco-2, we investigated the relationship between the synthesis of the heat shock protein HSP70, detected by Western blot and oxygen radicals as well as lactate dehydrogenase (LDH) release, as measured in photometrical tests. RESULTS: Various periods of hypoxia and 30 min of reoxygenation resulted in an increased generation of superoxide as measured by the tetrazolium base 3-(4, 5-dimethylthiazol-2-yl)2,5-diphenyltetrazoliumbromide. The inhibitor of superoxide dismutase (SOD), diethyldithiocarbamate (DDC) increased and addition of SOD decreased intracellular superoxide levels. HSP70 synthesis was detectable after 2 h of hypoxia. Similar to superoxide production, DDC increased and SOD reduced the HSP70 synthesis. In contrast, the increased LDH release from the cells observed after hypoxia was not significantly altered by DDC and SOD. CONCLUSION: The production of superoxide correlates with HSP70 induction, but not with LDH release. We conclude that hypoxia/reoxygenation induces heat shock protein production, a result of protein damage, by increased superoxide generation, whereas superoxide does not correlate with membrane damage in Caco-2 cells.

Adenosine Triphosphate↗
PubMed1999

Comparison of a parasite lactate dehydrogenase-based immunochromatographic antigen detection assay (OptiMAL) with microscopy for the detection of malaria parasites in human blood samples.

Microscopic examination of blood smears remains the gold standard for malaria diagnosis, but is labor-intensive and requires skilled operators. Rapid dipstick technology provides a potential alternative. A study was conducted in The Gambia to compare the performance of OptiMAL, an immunochromatographic antigen detection assay for the diagnosis of malaria using parasite lactate dehydrogenase, against standard microscopy in patients with suspected malaria. For initial diagnosis of Plasmodium falciparum, irrespective of stage, this assay had a sensitivity of 91.3%, a specificity of 92%, a positive predictive value of 87.2%, and a negative predictive value of 94.7%. The sensitivity of the test decreased markedly at parasitemias < 0.01%. This assay can be used for the diagnosis of malaria in areas where microscopy is not available and for urgent malaria diagnosis at night and at weekends, when routine laboratories are closed and when relatively inexperienced microscopists may be on duty.

Animals↗