Correlation of the Tei index with invasive measurements of ventricular function in a porcine model.

BACKGROUND: The Doppler myocardial performance (Tei) index has been reported to be clinically useful in assessing left ventricular systolic and diastolic function in both adults and children. However, there are limited data to compare the Tei index with invasive measurements of ventricular function. We used a porcine model to directly correlate the Tei index with invasive indices of systolic and diastolic function. METHODS: Pressure volume loops were obtained from 10 pigs (32-45 kg). A micromanometer and a conductance catheter were placed in the left ventricle to record pressure and volume, respectively. A flow probe was placed around the ascending aorta to record cardiac output. Baseline pressure volume loops were generated during preload reduction through caval occlusion. Epicardial echocardiograms were performed just before the caval occlusion. Invasive indices including preload recruitable stroke work, ventricular stiffness constant, and cardiac output were assessed, as were noninvasive echocardiographic indices including Tei index and ejection fraction. An ischemic insult, ventricular fibrillation, was induced to alter ventricular function. After cardioversion and 40 minutes of reperfusion, echocardiographic and invasive measurements were repeated. RESULTS: There was a statistically significant inverse relationship between the percent change in Tei and the percent change in preload recruitable stroke work after ventricular fibrillation (r = -0.70, P =.02), although the correlation between the actual values of Tei and preload recruitable stroke work were not statistically significant. There was a statistically significant inverse relationship between the percent change in Tei and the percent change in cardiac output (r = -0.65, P =.03). There was a direct correlation between the value of Tei and the ventricular stiffness constant at baseline (r = 0.63, P <.05). As anticipated, the value of Tei was inversely related to ejection fraction by epicardial echocardiogram at baseline (r = -0.85, P <.001). The percent change in Tei was inversely related to the percent change in ejection fraction as well (r = -0.69, P <.05). CONCLUSIONS: This animal model is one of the first studies to demonstrate a direct correlation between the Tei index and systolic and diastolic invasive measurements of ventricular function. This supports the clinical use of this index as a measure of global ventricular function.     

The Bausch and Lomb keratometer does not measure the tangential radius of curvature

The purpose of this research was to determine if the conventional keratometer measures tangential or sagittal radius. A Bausch and Lomb keratometer was modified to enable an assessment of vertex radius and p-value to be made on convex conicoidal buttons of known surface form. Calculation of these two parameters was achieved assuming that the keratometer was measuring tangential radius and then repeated assuming a sagittal measurement. The resulting values could then be compared with those obtained by Form Talysurf analysis and by the use of an autokeratometer designed to measure sagittal radius. There was good agreement between the three instruments when the modified Bausch and Lomb keratometer was assumed to measure sagittal radius. We conclude that the Bausch and Lomb keratometer makes a radius measurement closer to the sagittal than the tangential radius of a conicoid of revolution.     

Subcortical shape alterations in major depressive disorder: Findings from the ENIGMA major depressive disorder working group

Alterations in regional subcortical brain volumes have been investigated as part of the efforts of an international consortium, ENIGMA, to identify reliable neural correlates of major depressive disorder (MDD). Given that subcortical structures are comprised of distinct subfields, we sought to build significantly from prior work by precisely mapping localized MDD-related differences in subcortical regions using shape analysis. In this meta-analysis of subcortical shape from the ENIGMA-MDD working group, we compared 1,781 patients with MDD and 2,953 healthy controls (CTL) on individual measures of shape metrics (thickness and surface area) on the surface of seven bilateral subcortical structures: nucleus accumbens, amygdala, caudate, hippocampus, pallidum, putamen, and thalamus. Harmonized data processing and statistical analyses were conducted locally at each site, and findings were aggregated by meta-analysis. Relative to CTL, patients with adolescent-onset MDD (≤ 21 years) had lower thickness and surface area of the subiculum, cornu ammonis (CA) 1 of the hippocampus and basolateral amygdala (Cohen's d = ?0.164 to ?0.180). Relative to first-episode MDD, recurrent MDD patients had lower thickness and surface area in the CA1 of the hippocampus and the basolateral amygdala (Cohen's d = ?0.173 to ?0.184). Our results suggest that previously reported MDD-associated volumetric differences may be localized to specific subfields of these structures that have been shown to be sensitive to the effects of stress, with important implications for mapping treatments to patients based on specific neural targets and key clinical features.     

Social media and professional identity: Pitfalls and potential

Introduction: Social media developments have completely changed how information is accessed and communicated. While great potential exists with these platforms, recent reports of online unprofessional behavior by doctors has threatened the medical professional identity; a matter of critical importance for clinicians and medical educators. This paper outlines a role for social media in facilitating support for clinicians and medical teachers; it will raise awareness of pitfalls and explain ethical and legal guidelines.

Methods: An analysis of inappropriate behaviors and conflicting attitudes regarding what is acceptable in online posts, including the inter-generational contrast in online presence and perceptions of where the boundaries lie.

Results and discussion: Guidance documents are analyzed and potentially confusing and conflicting statements are identified and clarified. The authors believe that clinicians and medical students must follow ethical imperatives in both personal and professional spheres.

Conclusions: It is essential that medical educational and professional bodies encourage clinicians to support one another and share information online while providing clear legal and ethical advice on maintaining standards and avoiding common pitfalls. Education on the responsible use of social media and associated risk awareness should be a priority for medical school curricula.     

Bioactive acylphloroglucinols from Hypericum densiflorum

Three acylphloroglucinol derivatives have been isolated from the hexane and acetone extracts of the aerial parts of Hypericum densiflorum Pursch. The compounds were characterized by NMR spectroscopy and mass spectrometry and identified as 4‐geranyloxy‐2,6‐dihydroxybenzophenone (1), 4‐geranyloxy‐1‐(2‐methylpropanoyl)‐ phloroglucinol (2) and 4‐geranyloxy‐1‐(2‐methylbutanoyl)‐phloroglucinol (3). Compounds 1–3 were evaluated for in vitro cell proliferation inhibitory activity against human breast (MCF‐7), lung (NCI H460), CNS (SF‐268), stomach (AGS) and colon (HCT‐116) tumor cell lines; antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA); inhibition of cyclooxygenase (COX‐1 and ‐2) enzymes; and antioxidant activity in the lipid peroxidation (LPO) assay. All three compounds showed moderate to strong antitumor, antibacterial, antioxidant and inhibition of COX‐2 activities. Also, this is the first reported occurrence of compound 3 in the Hypericum genus. Copyright © 2009 John Wiley & Sons, Ltd.     

Evaluation of centrifugation cultures of bronchoalveolar lavage fluid for the diagnosis of cytomegalovirus pneumonitis

Cytomegalovirus (CMV) pneumonitis is one of the most severe manifestations of CMV disease among immunocompromised patients. The diagnosis of CMV pneumonitis traditionally has required the use of invasive procedures such as lung biopsy. In this retrospective study, we evaluated a centrifugation culture method in samples of bronchoalveolar fluid for the noninvasive diagnosis of CMV pneumonitis. During a 9-mo period, 75 bronchoalveolar lavage samples were collected from 58 patients with pneumonitis. We analyzed the data from 21 patients in whom lung tissue samples were obtained within 14 days of the bronchoalveolar lavage. Centrifugation cultures of bronchoalveolar fluid were positive for CMV in 12 cases. CMV pneumonitis was confirmed in samples of lung tissue from five (42%) of the 12 patients, whereas no evidence of CMV pneumonitis was found in the remaining seven (58%) cases. Of nine patients with negative centrifugation cultures, CMV pneumonitis was confirmed in two (22%). When compared with conventional cultures, we found bronchoalveolar lavage fluid centrifugation cultures to be highly sensitive (100%) and specific (92%) for the detection of CMV infection. However, detection of CMV by centrifugation culture proved to be only moderately sensitive (71%) and nonspecific (50%) for the diagnosis of CMV pneumonitis.     

Colorimetric capnography to ensure correct nasogastric tube position

Purpose

We evaluate a procedure, combining colorimetric capnography with epigastric auscultation, to ensure nasogastric (NG) feeding tube correct position without any radiograph.

Methods

We first evaluated the accuracy of colorimetric capnography in detecting tracheal positioning in a control group of 100 mechanically ventilated patients. The procedure was thereafter evaluated in a study group including patients requiring an NG tube. The NG tube was first inserted 30 cm and connected to a colorimetric capnograph (first step). If the capnograph did not detect carbon dioxide, insertion was completed to a total distance of 50 cm. An epigastric auscultation after air insufflation and a second capnography (second step) were performed. A radiograph evaluated correct tube position.

Results

In the control group, colorimetric capnograph sensitivity to detect tracheal placement was 100%. In the study group, negative predictive value of first-step capnography to rule out tracheobronchial insertion was 100%. The association of a first-step negative capnography with a positive epigastric auscultation correctly identified all but one gastric insertions, yielding a sensitivity of 98.5% (95% confidence interval, 95.7-100). The positive predictive value of this association to detect gastric placement was 100%.

Conclusion

Colorimetric capnography combined with epigastric auscultation is safe and accurate in ensuring correct gastric tube insertion.