Predicting Clostridium difficile Stool Cytotoxin Results in Hospitalized Patients with Diarrhea

OBJECTIVE: To validate a model for the prediction of Clostridium difficile cytotoxin assay results, and to identify a subgroup of patients with a very low likelihood of C. difficile-associated disease in whom the yield of routine cytotoxin testing is low. DESIGN: Prospective cohort study. Relevant clinical symptoms, signs, and antibiotic exposure were recorded before reporting of assay results. Each predictor was assigned a score based on regression coefficients, and patients were stratified according to their total score. SETTING: Two urban, tertiary care, university hospitals. PATIENTS: A total of 609 consecutive adult inpatients who received testing for C. difficile cytotoxin during a 3-month period in 1994. MEASUREMENTS AND MAIN RESULTS: The prevalence of positive cytotoxin assays was 8% in the validation set, compared with 14% in the derivation set. Defining patients without both prior antibiotic use and at least one symptom predictor (significant diarrhea or abdominal pain) as a low-risk subgroup, the misclassification rate was 2.8% (5/177) for assay results; of the five misclassified cases patients, only one was judged to have C. difficile-associated disease. Use of this rule to identify low-risk patients could have potentially averted 29% of all cytotoxin assays. CONCLUSIONS: Exposure to role models in a particular clinical field is strongly associated with medical students' choice of clinical field for residency training. Knowing which characteristics students look for in their role models should help identify the physicians who may be most influential in medical students' career choice.     

Association of G-33A polymorphism in the thrombomodulin gene with myocardial infarction in Koreans.

Thrombomodulin (TM), a thrombin receptor expressed on the endothelial surface, is known to play an important role in the anti-thrombogenic system in vivo. In this study, we examined the effects of 3 single-nucleotide polymorphisms (SNPs) in the TM gene (G-33A, C1418T and C1922T) on the development of myocardial infarction (MI) in Koreans. We found that G-33A was a common SNP (the minor allele frequency was 0.09) in Koreans. Eighty-five MI patients who had received coronary angiography were enrolled and were divided into 3 groups according to the number of coronary arteries in which stenosis was found angiographically (1-vessel disease (1VD) to 3-vessel disease (3VD)). The criterion of coronary stenosis was 50% or more stenosis on angiography. In addition, 102 controls (CONT) who had no significant stenosis were employed. The number of AA/GA genotypes of G-33A was found to be significantly greater in the 1VD than in the CONT (p=0.004 by chi2-test) while no significant difference was found between the multivessel disease (2-3VD) and the CONT. Multiple logistic analysis showed that G-33A was an independent risk factor for the 1VD with an odds ratio of 4.63 (95% confidence interval; 1.62-13.3). C1418T and C1922T were both in linkage disequilibrium with G-33A; however, they were not independent risks for either the 1VD or the 2-3VD. A reporter gene assay showed that G-33A had a significant effect on the TM promoter activity. These results indicated that G-33A polymorphism in TM might be a genetic risk factor for myocardial infarction.     

Successful application of burst spinal cord stimulation for refractory upper limb pain: a case series

Spinal cord stimulation (SCS) has been used to treat sustained pain that is intractable despite various types of treatment. However, conventional tonic waveform SCS has not shown promising outcomes for spinal cord injury (SCI) or postamputation pain. The pain signal mechanisms of burst waveforms are different to those of conventional tonic waveforms, but few reports have presented the therapeutic potential of burst waveforms for the abovementioned indications. This current case report describes two patients with refractory upper limb pain after SCI and upper limb amputation that were treated with burst waveform SCS. While the patients could not obtain sufficient therapeutic effect with conventional tonic waveforms, the burst waveforms provided better pain reduction with less discomfort. However, further studies are necessary to better clarify the mechanisms and efficacy of burst waveform SCS in patients with intractable pain.     

Hypofractionated radiotherapy with Tomotherapy for patients with hepatic oligometastases: retrospective analysis of two institutions

To evaluate the efficacy and toxicity for patients with hepatic oligometastases, receiving hypofractionated radiotherapy with Tomotherapy to the liver. A total of 42 patients with 54 hepatic lesions, who had been treated from 2007 to 2011 at two institutions, were retrospectively reviewed for this study. All the patients received radical resections of the primary tumor, and had been presented with one to two hepatic lesions. The radiation dose of 40–75 Gy in 10–20 fractions (median, 50 Gy in 10 fractions) was delivered for the planning target volume. At a median follow-up time of 15 months, 1- and 2-year local control (LC) rates were 59.9 and 49.0 %, respectively. The 1- and 2-year overall survival (OS) rates were 60.0 and 44.0 %, respectively. Maximal tumor diameter of <3 cm and biologically effective dose (BED) of ≥100 Gy_α/β=10 were significantly associated with higher LC and OS. Primary colorectal cancer tended to be associated with higher LC (P = 0.075), and was significantly associated with higher OS (P = 0.037). 12 (28.6 %) of the 42 patients had grade 1–2 toxicities, and grade 3 or higher toxicity did not occur. Hypofractionated radiotherapy with Tomotherapy was safe for patients with hepatic oligometastases. The maximal tumor diameter of <3 cm and BED of ≥100 Gy_α/β=10 were significant prognostic factors for higher local control and survival, and primary colorectal cancer patients had statistically higher overall survival than the others.     

Layer- and cell-type-specific tonic GABAergic inhibition of pyramidal neurons in the rat visual cortex

Tonic inhibition mediated by persistent activation of γ-aminobutyric acid_A (GABA_A) receptors by ambient GABA plays a crucial role in the regulation of network excitability and neuronal signal processing. Varying degrees in the strength of tonic inhibition were detected across different cell types throughout the brain. Since sensory information flows through cortical layers in a specific order, the characteristics of tonic inhibition in different cortical layers are of interest. Therefore, we examined the properties of tonic inhibition in pyramidal neurons (PyNs) throughout the rat visual cortex. Layer 2/3 PyNs and burst-spiking PyNs in layers 5 and 6 showed prominent tonic GABA_A currents. Tonic GABA_A currents in layer 4 star PyNs and regular-spiking PyNs in layers 5 and 6 were much weaker. The magnitude of tonic currents correlated well with the inhibition of spike generation. The amplitude of tonic GABA_A currents measured with bicuculline and gabazine, the two different GABA_A receptor blockers, did not differ. The differences in the expression levels of extrasynaptic GABA_A receptors might be the major contributor to the differences in tonic GABA_A currents among cell types. Furthermore, α5 subunits might contribute significantly to tonic currents in infragranular burst-spiking PyNs, especially in layer 5. These results suggest that ambient GABA might exert differential effects on the neuronal integration in a layer- and cell-type-specific manner and thus contribute to the processing of sensory properties by selectively tuning the signals flowing through the visual cortex.     

Lack of association between hepatitis B virus pre‐S mutations and recurrence after surgical resection in hepatocellular carcinoma

Pre‐S mutation of hepatitis B virus (HBV) is known to be a risk factor for hepatocarcinogenesis. A previous study suggested that pre‐S mutation(s) may associate with increased recurrence after surgical resection. In the present study, 64 patients with HBV‐related hepatocellular carcinoma (HCC) were categorized into two groups according to the presence or absence of pre‐S mutation(s). The clinicopathological variables of the two groups were analyzed to assess the relationship between pre‐S mutations and postoperative recurrence. Nineteen patients (29.7%) had pre‐S mutations;13 had a pre‐S deletion, three had a pre‐S2 start codon mutation, two patients had both a pre‐S deletion, and a pre‐S2 start codon mutation, and one patient had a pre‐S2 insertion. The two groups did not differ in terms of baseline clinicopathological parameters. Cirrhosis and satellite lesion(s) were predictive factors for postoperative recurrence and poor overall survival. Recurrence‐free survival (P = 0.320) and overall survival (P = 0.238) did not differ significantly when pre‐S mutations were present. In conclusion, this study did not find evidence supporting the notion that pre‐S mutation(s) are associated with postoperative recurrence after surgical resection. J. Med. Virol. 85:589–596, 2013. © 2013 Wiley Periodicals, Inc.     

Characteristics Associated with Racial Disparities in Illness Beliefs of Patients with Heart Failure

African Americans have greater misperceptions about heart failure (HF) than Caucasians. We examined socioeconomic and medical history factors to determine if they explain differences in accuracy of HF illness beliefs by race. 519 patients completed an illness beliefs and socioeconomic status survey. After establishing univariate associations by race, linear regression with backward selection was used to identify factors associated with HF illness beliefs accuracy. HF illness beliefs were less accurate among African Americans (p < .01). In multivariate models, race remained a predictor of HF illness beliefs accuracy, as did education level and living status (all ps ≤ .01). Illness beliefs of African Americans were inaccurate and independently associated with social support and education level. Health care providers must consider patient education processes as a possible cause of differences and focus on what and how they teach, literacy level, materials used, and family engagement and education.     

The Extent of Late Gadolinium Enhancement Can Predict Adverse Cardiac Outcomes in Patients with Non-Ischemic Cardiomyopathy with Reduced Left Ventricular Ejection Fraction: A Prospective Observational Study

ObjectiveThe clinical course of an individual patient with heart failure is unpredictable with left ventricle ejection fraction (LVEF) only. We aimed to evaluate the prognostic value of cardiac magnetic resonance (CMR)-derived myocardial fibrosis extent and to determine the cutoff value for event-free survival in patients with non-ischemic cardiomyopathy (NICM) who had severely reduced LVEF.Materials and MethodsOur prospective cohort study included 78 NICM patients with significantly reduced LV systolic function (LVEF < 35%). CMR images were analyzed for the presence and extent of late gadolinium enhancement (LGE). The primary outcome was major adverse cardiac events (MACEs), defined as a composite of cardiac death, heart transplantation, implantable cardioverter-defibrillator discharge for major arrhythmia, and hospitalization for congestive heart failure within 5 years after enrollment.ResultsA total of 80.8% (n = 63) of enrolled patients had LGE, with the median LVEF of 25.4% (19.8–32.4%). The extent of myocardial scarring was significantly higher in patients who experienced MACE than in those without any cardiac events (22.0 [5.5–46.1] %LV vs. 6.7 [0–17.1] %LV, respectively, p = 0.008). During follow-up, 51.4% of patients with LGE ≥ 12.0 %LV experienced MACE, along with 20.9% of those with LGE ≤ 12.0 %LV (log-rank p = 0.001). According to multivariate analysis, LGE extent more than 12.0 %LV was independently associated with MACE (adjusted hazard ratio, 6.71; 95% confidence interval, 2.54–17.74; p < 0.001).ConclusionIn NICM patients with significantly reduced LV systolic function, the extent of LGE is a strong predictor for long-term adverse cardiac outcomes. Event-free survival was well discriminated with an LGE cutoff value of 12.0 %LV in these patients.