Dissolution mechanism of calcium apatites in acids: A review of literature

Eight dissolution models of calcium apatites (both fluorapatite and hydroxyapatite) in acids were drawn from the published literature, analyzed and discussed. Major limitations and drawbacks of the models were conversed in details. The models were shown to deal with different aspects of apatite dissolution phenomenon and none of them was able to describe the dissolution process in general. Therefore, an attempt to combine the findings obtained by different researchers was performed which resulted in creation of the general description of apatite dissolution in acids. For this purpose, eight dissolution models were assumed to complement each other and provide the correct description of the specific aspects of apatite dissolution. The general description considers all possible dissolution stages involved and points out to some missing and unclear phenomena to be experimentally studied and verified in future. This creates a new methodological approach to investigate reaction mechanisms based on sets of affine data, obtained by various research groups under dissimilar experimental conditions.

Electrodermal mapping: A new technology

AIM: To provide the first objective data to show that the electrical conditions of an acupuncture point and a non acupuncture point are different.

METHODS: A newly developed multi-channel skin resistance measuring system is used to characterize the variability in electrical resistance measurements in and around an acupoint, a non-acupoint and a scar. The system measures the electrical skin resistance at 48 points, both absolutely and continuously. The study was performed at the Medical University of Graz in 10 male volunteers, aged between 20 and 30 years and of eurocaucasian descent. With software developed along with the hardware, both a high-resolution measurement and a graphical presentation of possible changes in electrical resistance in the region of interest are possible.

RESULTS: Using the new electrodermal mapping system, differences in skin resistance of an acupoint, a non-acupoint and around a scar could be observed. The values varied within a range of up to 100-500 kOhm. Thermography measurements for control reasons in the same spot did not show these changes.

CONCLUSION: Electrodermal mapping is an innovative method for highly precise skin resistance measurements.

Improving psychotherapy research: The example of mindfulness based interventions

The increasing number and sophistication of available psychotherapies suggests that a critical appraisal of the methodological issues of psychotherapy studies is highly needed. Several key questions regarding the efficacy of a given intervention, the understanding of whether positive effects observed following the delivery of a psychotherapeutic intervention are specifically attributable to the intervention itself or to other "non specific" factors, such as benefit expectations, therapist attention and support, and the possibility of improving psychotherapy research need an answer. This, in turn, could provide clinicians with more rigorous information about psychotherapy outcomes and could properly address several shortcomings that are frequently observed in current psychotherapy studies. Accordingly, in this editorial I will highlight some of the most important critical issues that a well designed psychotherapy study should take into account, including the need for appropriate control groups, appropriate randomization and blinding procedures, and the importance of performing appropriately powered studies that include a sufficiently long follow-up period. Finally, I will build on my expertise in the field of mindfulness based interventions, in particular mindfulness based stress reduction and mindfulness based cognitive therapy, to show how such issues have been and can be successfully implemented in the design of future psychotherapy studies.

What is the purpose of launching the World Journal of Methodology?

Congratulations to the publisher, members of the editorial board of the journal, all the authors and readers for launching the World Journal of Methodology (WJM) as a new member of the World series journal family! Scientific advances and important breakthroughs have been facilitated by well developed methodologies or techniques and any misleading findings and theories are exclusively attributable to certain methodological defects. Thus, the role of appropriate methodologies in the development of science and technology cannot be overemphasized and the need for inaugurating this new journal is self-evident. The WJM is a peer-reviewed open-access periodical centered in biomedical sciences but with multidisciplinary coverage. If you want to share any new methodologies, any experiences of the application or improvement of such methodologies and any methodology-related academic issues with your peers, you will find the WJM a good media to publish your papers!

Risk of fracture and pneumonia from acid suppressive drugs

A recently published systematic review and meta-analysis, incorporating all relevant studies on the association of acid suppressive medications and pneumonia identified up to August 2009, revealed that for every 200 patients, treated with acid suppressive medication, one will develop pneumonia. They showed the overall risk of pneumonia was higher among people using proton pump inhibitors (PPIs) [adjusted odds ratio (OR) = 1.27, 95% CI: 1.11-1.46, I² = 90.5%] and Histamine_-2 receptor antagonists (H₂RAs) (adjusted OR = 1.22, 95% CI: 1.09-1.36, I² = 0.0%). In the randomized controlled trials, use of H₂RAs was associated with an elevated risk of hospital-acquired pneumonia (relative risk 1.22, 95% CI: 1.01-1.48, I² = 30.6%). Another meta-analysis of 11 studies published between 1997 and 2011 found that PPIs, which reduce stomach acid production, were associated with increased risk of fracture. The pooled OR for fracture was 1.29 (95% CI: 1.18-1.41) with use of PPIs and 1.10 (95% CI: 0.99-1.23) with use of H₂RAs, when compared with non-use of the respective medications. Long-term use of PPIs increased the risk of any fracture (adjusted OR = 1.30, 95% CI: 1.15-1.48) and of hip fracture risk (adjusted OR = 1.34, 95% CI: 1.09-1.66), whereas long-term H₂RA use was not significantly associated with fracture risk. Clinicians should carefully consider when deciding to prescribe acid-suppressive drugs, especially for patients who are already at risk for pneumonia and fracture. Since it is unnecessary to achieve an achlorhydric state in order to resolve symptoms, we recommend using the only minimum effective dose of drug required to achieve the desired therapeutic goals.

Challenges in estimating reproducibility of imaging modalities

Estimating reproducibility is often wrongly thought of as basic science. Although it has a significant clinical relevance, its importance is underestimated. It was Alexander Pope in 1732 who was first to understand the value of reproducibility, with his famous comment “Who shall decide when doctors disagree?”. Pope’s question concerns the medical doctors’ opinion on a patient’s status, which from a statistical point of view may be considered a categorical variable. However, the same question may be posed for continuous quantitative variables. Reproducibility is complementary to variability: the larger the variability, the lower the reproducibility, and vice versa. Thus, we can think at them as interchangeable, even thought statistical methods have been developed for the estimation of variability. The question now is “Why do we need to know the reproducibility of measurements? ”. The most important and simplest answer is that we need to know how reliable a measured value or a subjective judgment is before taking clinical decisions based on this measurement/judgment. Integrating this knowledge in clinical practice is a key aspect of evidence-based medicine.