Understanding mineral trioxide aggregate/Portland-cement: a review of literature and background factors

AIM

This was to carry out a review of the literature concerning mineral trioxide aggregate (MTA) and Portland cement with regards to clinical, biological and mechanical findings and a possible substitution of MTA through Portland cement for endodontic use.

STUDY DESIGN

Electronic literature search of scientific papers from January 1993 to January 2009 was carried out on the MEDLINE and Scopus databases using specific key words. In total, 57 papers were identified that dealt with MTA and Portland cement in a relevant way.

RESULTS

The review of 50 papers conforming to the applied criteria showed that MTA and Portland cements have the same clinical, biological and mechanical properties. In animal experiments and technical characterisations both materials seemed to have very similar properties. The only difference is bismuth oxide in MTA added for better radio opacity. It seems likely that MTA materials are based on industrial Portland cements mixed with bismuth oxide. More studies, especially some long-term studies comparing MTA and Portland cement, are necessary.

CONCLUSION

The existing literature gives a solid base for clinical studies with Portland cement in order to replace MTA as an endodontic material. Portland cement could be a substitute for most endodontic materials used in primary teeth.

Distinct mechanistic activity profile of pralatrexate in comparison to other antifolates in in vitro and in vivo models of human cancers

PURPOSE

This study evaluated mechanistic differences of pralatrexate, methotrexate, and pemetrexed.

METHODS

Inhibition of dihydrofolate reductase (DHFR) was quantified using recombinant human DHFR. Cellular uptake and folylpolyglutamate synthetase (FPGS) activity were determined using radiolabeled pralatrexate, methotrexate, and pemetrexed in NCI-H460 non-small cell lung cancer (NSCLC) cells. The tumor growth inhibition (TGI) was assessed using MV522 and NCI-H460 human NSCLC xenografts.

RESULTS

Apparent K ( i ) values for DHFR inhibition were 45, 26, and >200 nM for pralatrexate, methotrexate, and pemetrexed, respectively. A significantly greater percentage of radiolabeled pralatrexate entered the cells and was polyglutamylatated relative to methotrexate or pemetrexed. In vivo, pralatrexate showed superior anti-tumor activity in both NSCLC models, with more effective dose-dependent TGI in the more rapidly growing NCI-H460 xenografts.

CONCLUSIONS

Pralatrexate demonstrated a distinct mechanistic and anti-tumor activity profile relative to methotrexate and pemetrexed. Pralatrexate exhibited enhanced cellular uptake and increased polyglutamylation, which correlated with increased TGI in NSCLC xenograft models.

Prophylactic immunisation against traveller's diarrhoea caused by enterotoxin-forming strains of Escherichia coli and against cholera: does it make sense and for whom?

Traveller's diarrhoea (TD) constitutes the most common disease relevant to travel medicine with ETEC as the leading causative pathogen. Cholera is the most serious, but very rare form of TD. ETEC and cholera share pathogenic mechanisms by producing a toxin that has an 80% amino acid homology. A consensus of German-speaking experts sees the indication to use the whole cell/B subunit oral cholera vaccine (WC--BS) if cholera is a risk for aid workers or travellers with an anticipated threat of cholera who stay under poor hygienic conditions. The use of the vaccine should be considered in the indication to avoid ETEC TD for travellers with predisposing illness or medication or for travellers at risk to develop a serious course.

Clinical and immune response to undiluted and diluted smallpox vaccine

QUESTION UNDER STUDY

To assess clinical reactions, immune responses and adverse events to undiluted, three- and sixfold diluted Lister strain vaccine stockpiled in Switzerland.

METHODS

A prospective, triple-blinded, randomised, parallel group clinical trial was performed.

RESULTS

From 2001 to 2007 104 persons with an indication for vaccinia vaccination were recruited. They had a median age of 33 years (range 18-65), 56 (53.8%) were re-vaccinees and 48 (46.2%) primary vaccinees. There was no statistically significant variation in the proportion of revaccinees between diluted and undiluted vaccine groups (75% vs 51%, p = 0.118). With an overall clinical take rate (major reaction) of 97.1% the majority of the vaccinia-naïve participants exhibited an at least fourfold increase of neutralising antibody titres (32/38, 84.2%) post-vaccination. Interestingly this proportion was lower among re-vaccinees (29/46, 63.0%, p = 0.048). No significant difference was observed in the take rate or at least fourfold seroconversion rate between the threefold and sixfold diluted vaccine doses. Adverse events were reported by 98 (94.2%) participants, not accounting for itching at the vaccination site.

CONCLUSION

Subjects requiring immunisation were successfully (re-) vaccinated with undiluted as well as with three- or sixfold diluted vaccinia vaccine. Our findings complement previous studies with respect to the clinical take rate and immune response. The rate of adverse events was substantial but not unexpected and no severe adverse events occurred. In conclusion, the existing smallpox vaccine stockpile might be expanded by administering three- or sixfold diluted vaccine doses combined with a careful pre-vaccination screening and extensive instructions to vaccinees.

Two-step tuberculin skin test and booster phenomenon prevalence among Brazilian medical students

SETTING

Five medical schools in three cities in Rio de Janeiro State, Brazil, with different tuberculosis (TB) incidence rates.

OBJECTIVE

To evaluate the prevalence of the booster phenomenon and its associated factors in a young universally BCG-vaccinated TB-exposed population.

DESIGN

A two-step tuberculin skin test (TST) was performed among undergraduate medical students. Boosting was defined as an induration > or =10 mm in the second TST (TST2), with an increase of at least 6 mm over the first TST (TST1). The association of boosting with independent variables was evaluated using multivariate analysis.

RESULTS

Of the 764 participants (mean age 21.9 +/- 2.7 years), 672 (87.9%) had a BCG scar. The overall booster phenomenon prevalence was 8.4% (95%CI 6.5-10.6). Boosting was associated with TST1 reactions of 1-9 mm (aOR 2.5, 95%CI 1.04-5.9) and with BCG vaccination, mostly after infancy, i.e., after age two years (aOR 9.1, 95%CI 1.2-70.7).

CONCLUSION

The prevalence of the booster phenomenon was high. A two-step TST in young BCG-vaccinated populations, especially in those with TST1 reactions of 1-9 mm, can avoid misdiagnosis as a false conversion and potentially reduce unnecessary treatment for latent TB infection.

Hepatitis E, Helicobacter pylori and peptic ulcers in workers exposed to sewage: a prospective cohort study

BACKGROUND

Workers exposed to sewage may have an increased risk of infection by Helicobacter pylori and hepatitis E virus (HEV).

OBJECTIVES

To assess the incidence of clinical hepatitis E and peptic ulcers and the seroconversion rate of antibodies to H pylori and HEV in workers with and without sewage exposure.

METHODS

332 workers exposed to sewage and a control group of 446 municipal manual workers (61% participation rate) entered a prospective cohort study with clinical examination and determination of antibodies to H pylori and HEV (immunoglobulins G and A or G and M, respectively). Survival curves were examined with log rank tests and Cox regressions. Travelling to endemic areas, socioeconomic level, age, country of childhood, number of siblings, and personal protective equipment were considered as the main confounding factors.

RESULTS

Incidence of clinical hepatitis E was not increased in sewage workers. One peptic ulcer and three eradications were recorded in sewage workers compared with no peptic ulcers and 12 eradications in control workers. Incidence rates of approximately 0.01, 0.10, and 0.15 seroconversion/person-year for hepatitis E, H pylori IgG and H pylori IgA, respectively, were found in both exposed and non-exposed workers. Survival curves did not show an increased risk in sewage workers and no association with any exposure indicator was found. Sensitivity analyses did not alter these results.

CONCLUSIONS

Sewage does not appear to be a source of occupational infection by H pylori or HEV in trained sewage workers with personal protective equipment working in a region with good sanitation.

PS II model-based simulations of single turnover flash-induced transients of fluorescence yield monitored within the time domain of 100 ns-10 s on dark-adapted Chlorella pyrenoidosa cells

The set up described in Steffen et al. (Biochemistry 40:173-180, 2001) was used to monitor in the time domain from 100 ns to 10 s single turnover flash-induced transients of the normalized fluorescence yield (SFITFY) on dark-adapted cells of the thermophilic algae Chlorella pyrenoidosa Chick. Perfect data fit was achieved within the framework of a previously proposed model for the PS II reaction pattern (Lebedeva et al., Biophysics 47:968-980, 2002; Belyaeva et al., Biophysics 51:860-872, 2006) after its modification by taking into account nonradiative decay processes including nonphotochemical quenching due to time-dependent populations of P680(+*) and (3)Car. On the basis of data reported in the literature, a consistent set of rate constants was obtained for electron transfer at the donor and acceptor sides of PS II, pH in lumen and stroma, the initial redox state of plastoquinone pool and the rate of plastoquinone oxidation. The evaluation of the rate constant values of dissipative processes due to quenching by carotenoid triplets in antennae and P680(+*)Q(A)(-*) recombination as well as the initial state populations after excitation with a single laser flash are close to that outlined in (Steffen et al., Biochemistry 44:3123-3133, 2005a). The simulations based on the model of the PS II reaction pattern provide information on the time courses of population probabilities of different PS II states. We analyzed the maximum (F(m)(STF)) and minimum (F(0)) of the normalized FL yield dependence on the rate of the recombination processes (radiative and dissipative nonradiative) and of P680(+*) reduction. The developed PS II model provides a basis for theoretical comparative analyses of time-dependent fluorescence signals, observed at different photosynthetic samples under various conditions (e.g. presence of herbicides, other stress conditions, excitation with actinic pulses of different intensity, and duration).

Clinical and immune response to undiluted and diluted smallpox vaccine

QUESTION UNDER STUDY

To assess clinical reactions, immune responses and adverse events to undiluted, three- and sixfold diluted Lister strain vaccine stockpiled in Switzerland.

METHODS

A prospective, triple-blinded, randomised, parallel group clinical trial was performed.

RESULTS

From 2001 to 2007 104 persons with an indication for vaccinia vaccination were recruited. They had a median age of 33 years (range 18-65), 56 (53.8%) were re-vaccinees and 48 (46.2%) primary vaccinees. There was no statistically significant variation in the proportion of revaccinees between diluted and undiluted vaccine groups (75% vs 51%, p = 0.118). With an overall clinical take rate (major reaction) of 97.1% the majority of the vaccinia-naïve participants exhibited an at least fourfold increase of neutralising antibody titres (32/38, 84.2%) post-vaccination. Interestingly this proportion was lower among re-vaccinees (29/46, 63.0%, p = 0.048). No significant difference was observed in the take rate or at least fourfold seroconversion rate between the threefold and sixfold diluted vaccine doses. Adverse events were reported by 98 (94.2%) participants, not accounting for itching at the vaccination site.

CONCLUSION

Subjects requiring immunisation were successfully (re-) vaccinated with undiluted as well as with three- or sixfold diluted vaccinia vaccine. Our findings complement previous studies with respect to the clinical take rate and immune response. The rate of adverse events was substantial but not unexpected and no severe adverse events occurred. In conclusion, the existing smallpox vaccine stockpile might be expanded by administering three- or sixfold diluted vaccine doses combined with a careful pre-vaccination screening and extensive instructions to vaccinees.

[Comparative biomechanical studies following automated percutaneous nucleotomy and diskotomy]

APLD is considered as the last step of conservative treatment for lumbar disc herniation assuming that a negative biomechanical effect of APLD is not expected. Biomechanical effects of APLD were investigated in comparison to open discectomy. APLD decreased disc height less than open discectomy and increased instability and flexibility less. The position of the center of rotation was not significantly altered.

The anterolateral approach leads to less disruption of the femoral head-neck blood supply than the posterior approach during hip resurfacing

In 12 patients, we measured the oxygen concentration in the femoral head-neck junction during hip resurfacing through the anterolateral approach. This was compared with previous measurements made for the posterior approach. For the anterolateral approach, the oxygen concentration was found to be highly dependent upon the position of the leg, which was adjusted during surgery to provide exposure to the acetabulum and femoral head. Gross external rotation of the hip gave a significant decrease in oxygenation of the femoral head. Straightening the limb led to recovery in oxygen concentration, indicating that the blood supply was maintained. The oxygen concentration at the end of the procedure was not significantly different from that at the start. The anterolateral approach appears to produce less disruption to the blood flow in the femoral head-neck junction than the posterior approach for patients undergoing hip resurfacing. This may be reflected subsequently in a lower incidence of fracture of the femoral neck and avascular necrosis.

Real time PCR for the assessment of CD8+ T cellular immune response after prophylactic vaccinia vaccination

BACKGROUND

The magnitude of specific CD8+ T cell reactivity responsible for vaccine-induced protection against smallpox infection has not yet been fully elucidated. Among other techniques, RT-PCR for the monitoring of cytokine release in effector T cells against tumor and viral antigens has demonstrated a novel promising method.

OBJECTIVE

To determine the functional status of antigen specific CD8+ T cells in healthy participants before and 4 weeks after prophylactic vaccination (Lister strain) against smallpox using quantitative real-time PCR (qRT-PCR).

STUDY DESIGN

Changes of interferon-gamma (IFNgamma) mRNA expression levels on short term ex vivo peptide antigen stimulation were measured. The corresponding specific CD8+ T cell reactivity was then displayed as CD8-normalized IFN-gamma levels (IFN-gamma/CD8 ratio).

RESULTS

We found a 5-9 fold increase of CD8+ T cell reactivity in three out of four vaccinated individuals. The kinetics and strength determined in responders reveal a virus specific T cell effector repertoire pre-vaccination and a corresponding functional state after immunization comparable also to data obtained from tetramer- and ELISPOT analysis.

CONCLUSIONS

Apart from protective vaccinia-specific neutralizing antibodies, the presence of antigen-specific CD8+ T-cells has been demonstrated after vaccinia vaccination. In concordance with others, results from this PCR-based study indicate that this smallpox vaccine induces strong vaccinia virus-specific CD8+ and IFN-gamma producing T cell responses.

Inter-disciplinary European guidelines on surgery of severe obesity

In 2005, for the first time in European history, an extraordinary Expert panel named 'The BSCG' (Bariatric Scientific Collaborative Group), was appointed through joint effort of the major European Scientific Societies which are active in the field of obesity management. Societies that constituted this panel were: IFSO - International Federation for the Surgery of Obesity, IFSO-EC - International Federation for the Surgery of Obesity - European Chapter, EASO - European Association for Study of Obesity, ECOG - European Childhood Obesity Group, together with the IOTF (International Obesity Task Force) which was represented during the completion process by its representative. The BSCG was composed not only of the top officers representing the respective Scientific Societies (four acting presidents, two past presidents, one honorary president, two executive directors), but was balanced with the presence of many other key opinion leaders in the field of obesity. The BSCG composition allowed the coverage of key disciplines in comprehensive obesity management, as well as reflecting European geographical and ethnic diversity. This joint BSCG expert panel convened several meetings which were entirely focused on guidelines creation, during the past two years. There was a specific effort to develop clinical guidelines, which will reflect current knowledge, expertise and evidence based data on morbid obesity treatment.

[Triple pelvic osteotomy (according to Tönnis and Kalchschmidt) in the treatment of acetabular dysplasia--medium-term results]

AIM

The triple pelvic osteotomy according to Tönnis and Kalchschmidt has gained major significance in the surgical treatment of acetabular dysplasia in adolescents and adults. The curative and prophylactic potentials of this operative procedure are reviewed in this study by means of a clinical and radiological follow-up trial.

METHODS

34 patients/38 hip joints treated by the triple pelvic osteotomy between 1996 and 2005 were reviewed clinically and radiologically with an average follow-up of 3.5 years. The radiological classification into grades of deviation was done according to Tschauner et al., clinically the preoperative Harris hip score was determined, as well as common epidemiologic parameters. At follow-up, the preoperatively determined radiological and clinical parameters were controlled and subjected to statistical analysis using Student's t-test for the comparison of means between two paired groups. Finally, the subjective assessment of the operation's result by the patients was registered.

RESULTS

A statistically highly significant amelioration of the Harris hip score, relevant radiological angles and grades of deviation could be demonstrated at follow-up. This fact coincided with a high or very high patient satisfaction in 81.7% of the cases. The conversion rate to alloarthroplasty was 2.6%. The complication profile was within the scope of similar elective hip surgeries.

CONCLUSION

The triple pelvic osteotomy according to Tönnis and Kalchschmidt has shown in the present study a high and constant potential with regard to reduction/absence of disorders as well as a statistically highly significant amelioration of clinical scores and relevant radiological angles. In our experience, this surgical method can be regarded as the joint-preserving method of choice in the cardinal indication of adolescent and adult acetabular dysplasia.

[Surgical procedures for severely obese patients: impact and long-term results]

Obesity is a multifactorial, genetically-determined, neuroendocrine, and chronic condition. Conservative treatment of patients with class II and III obesity (BMI >35 kg/m(2)) has only modest long-term success. Surgical procedures have been used since 1954, and the methods used are continually being updated and improved. With experienced surgeons, patients can achieve a weight reduction from around 50% with purely restrictive procedures, increasing to 75% with combined restrictive-malabsorptive methods. All weight-loss methods offer a considerable improvement or elimination of obesity-related co-morbidities and substantially improvement of quality of life. Well-documented, long-term studies reveal a perioperative mortality of 0.2-1.0%, dependent on the surgeon's experience, and a maximum perioperative morbidity of 20%. Bariatric surgery is accepted as evidence based, safe and effective treatment of obesity.

Safety and immunogenicity profile of an experimental hepatitis B vaccine adjuvanted with AS04

The reactogenicity and safety of an experimental hepatitis B (HB) vaccine containing adjuvant system (AS04) was compared with a licensed vaccine in a phase III, single-blind, randomised study in healthy volunteers >or=15 years of age. A total of 1303 subjects were enrolled to receive either two doses of HB-AS04 (0, 6 months) or three doses of the comparator vaccine (0, 1, 6 months). Two doses of HB-AS04 elicited seroprotection rates close to 100% and two-fold higher GMTs than the comparator vaccine. Results showed that both vaccines were well tolerated and the general safety profile of HB-AS04 was similar to that of the comparator vaccine.

[Knowledge, attitudes and practices among travellers to tropical and subtropical countries]

Passengers with destinations in developing countries have been interviewed prior to departure on Zurich Airport. A total of 946 questionnaires were evaluated, 337 on travel related malaria prior to visiting an endemic country, 609 on vaccinations. This corresponds to a response rate of 72.3%. Among the respondents 550 (58.1%) had received travel health advice by a doctor. Overall, 25.5% were immunized against hepatitis A. While 70.4% of those who had obtained travel health advice carried medication against malaria, only 31.3% of those without such advice did so. Travel health advice resulted in a significantly increased appreciation of the risk of hepatitis A or malaria at the destination. Considerations on healthy travel should become a cornerstone in travel planning; special risk groups have been identified.

[Cup placement in hip replacement surgery -- A comparison of free-hand and computer assisted cup placement in total hip arthroplasty -- a multi-center study]

AIM

The purpose of the current study was to determine the accuracy of free hand and computer-assisted (CAS) cup placement.

MATERIAL AND METHODS

Between June 1985 and August 2001, 105 free-hand and from March to November 1999 80 total hip arthroplasties under computer assistance were implanted in the above mentioned centers. To determine the accuracy of the cups, the inclination and anteversion angles were measured. In all cases the cup position was measured with a CT-investigation of the pelvis. Statistical analysis was performed with the F-test.

RESULTS

With regard to the inclination and anteversion angles the variability of the cup position was significantly higher in the group of free hand implanted cups. In the CAS group we could not find any "extreme" positions.

CONCLUSION

Using computer-assisted surgery a significantly higher reproducible cup position can be obtained. Long time survey may present a lowering of the rate of early and late complications caused by better prostheses alignment in the follow up.

The accuracy of free-hand cup positioning--a CT based measurement of cup placement in 105 total hip arthroplasties

We studied 105 patients who received a total hip arthroplasty between June 1985 and August 2001 using freehand positioning of the acetabular cup. Using pelvic CT scan and the hip-plan module of SurgiGATE-System (Medivision, Oberdorf, Switzerland), we measured the angles of inclination and anteversion of the cup. Mean inclination angle was 45.8 degrees +/-10.1 degrees (range: 23.0-71.5 degrees ) and mean anteversion angle was 27.3 degrees +/-15.0 degrees (range: -23.5 degrees to 59.0 degrees ). We compared the results to the "safe" position as defined by Lewinnek et al. and found that only 27/105 cups were implanted within the limits of the safe position. We conclude that a safe position as defined by Lewinnek et al. [13] was only achieved in a minority of the cups that were implanted freehand.