Genetic variants of coagulation factor XIII,postmenopausal estrogen therapy,and risk of nonfatal myocardial infarction

We hypothesized that possession of either of 2 functional coagulation factor XIII polymorphisms, one within subunit A (Val34Leu) and one within subunit B (His95Arg), might modulate the prothrombotic effects of estrogen and help to explain the variation in incidence of arterial thrombotic events among postmenopausal women using hormone replacement therapy. In a population-based case-control study of 955 postmenopausal women, we assessed the associations of factor XIII genotypes and their interactions with estrogen therapy on risk of nonfatal myocardial infarction (MI). The presence of the factor XIIIA Leu34 allele was associated with a reduced risk of MI (odds ratio [OR] = 0.70, 95% confidence interval [95% CI] = 0.51-0.95). The presence of the factor XIIIB Arg95 allele had little association with MI risk. Neither factor XIII polymorphism alone significantly modified the association between the risk of MI and current estrogen use. In exploratory analyses, however, there was a significant factor XIII subunit gene-gene interaction. Compared to women homozygous for both common factor XIII alleles, the Arg95 variant was associated with a reduced risk of MI in the presence of the Leu34 variant (OR = 0.36, 95% CI = 0.17-0.75) but not in the absence of the Leu34 variant (OR = 1.11, 95% CI = 0.69-1.79). Moreover, among women who had at least 2 copies of the variant factor XIII alleles and were current estrogen users, the risk of MI was reduced by 70% relative to estrogen nonusers with fewer than 2 factor XIII variant alleles (P value for interaction =.03). If confirmed, these findings may permit a better assessment of the cardiovascular risks and benefits associated with postmenopausal estrogen therapy.     

Shot by a Gun … Missed by a Provider

Background

Botulism is a paralytic disease caused by the neurotoxin produced by Clostridium botulinum. The majority of cases are due to ingestion or injection drug use. Wound botulism from traumatic injury is exceedingly rare, with only one to two cases reported each year in the United States.

Fructose:Glucose Ratios—A Study of Sugar Self-Administration and Associated Neural and Physiological Responses in the Rat

This study explored whether different ratios of fructose (F) and glucose (G) in sugar can engender significant differences in self-administration and associated neurobiological and physiological responses in male Sprague-Dawley rats. In Experiment 1, animals self-administered pellets containing 55% F + 45% G or 30% F + 70% G, and Fos immunoreactivity was assessed in hypothalamic regions regulating food intake and reward. In Experiment 2, rats self-administered solutions of 55% F + 42% G (high fructose corn syrup (HFCS)), 50% F + 50% G (sucrose) or saccharin, and mRNA of the dopamine 2 (D2R) and mu-opioid (MOR) receptor genes were assessed in striatal regions involved in addictive behaviors. Finally, in Experiment 3, rats self-administered HFCS and sucrose in their home cages, and hepatic fatty acids were quantified. It was found that higher fructose ratios engendered lower self-administration, lower Fos expression in the lateral hypothalamus/arcuate nucleus, reduced D2R and increased MOR mRNA in the dorsal striatum and nucleus accumbens core, respectively, as well as elevated omega-6 polyunsaturated fatty acids in the liver. These data indicate that a higher ratio of fructose may enhance the reinforcing effects of sugar and possibly lead to neurobiological and physiological alterations associated with addictive and metabolic disorders.     

Accuracy of chitotriosidase activity and CCL18 concentration in assessing type I Gaucher disease severity. A systematic review with meta-analysis of individual participant data

Chitotriosidase activity and CCL18 concentration are interchangeably used for monitoring Gaucher disease (GD) activity, together with clinical assessment. However, comparative studies of these two biomarkers are scarce and of limited sample size. The aim of this systematic review with meta-analysis of individual participant data (IPD) was to compare the accuracy of chitotriosidase activity and CCL18 concentration for assessing type I GD severity. We identified cross-sectional and prospective cohort studies by searching Medline, EMBASE, and CENTRAL from January 1995 to June 2017, and by contacting research groups. The primary outcome was a composite of liver volume >1.25 multiple of normal (MN), spleen volume >5 MN, hemoglobin concentration <11 g/dL, and platelet count <100x109/L. Overall, IPD included 1,109 observations from 334 patients enrolled in nine primary studies, after excluding 111 patients with undocumented values and 18 patients with deficient chitotriosidase activity. IPD were unavailable for 14 eligible primary studies. The primary outcome was associated with a 5.3-fold (95% Confidence Interval [CI]: 4.2-6.6) and 3.0-fold (95% CI: 2.6-3.6) increase of the geometric mean for chitotriosidase activity and CCL18 concentration, respectively. The corresponding areas under the receiver operating characteristics curves were 0.82 and 0.84 (summary difference, 0.02, 95% CI: -0.02 to 0.05). The addition of chitotriosidase activity did not improve the accuracy of the CCL18 concentration. Estimates remained robust in the sensitivity analysis and consistent across subgroups. Neither the chitotriosidase activity nor the CCL18 concentration varied significantly according to a recent history of bone events among 97 patients. In conclusion, the CCL18 concentration is as accurate as chitotriosidase activity in assessing hematological and visceral parameters of GD severity and can be measured in all GD patients. This meta-analysis supports the use of CCL18 rather than chitotriosidase activity for monito-ring GD activity in routine practice.     

Therapeutic biliary endoscopy in patients over 90 years of age

Endoscopic retrograde cholangiopancreatography (ERCP) is an established method to treat bile duct obstruction. Besides, ERCP is one of the most stricking parts of interventional endoscopy and takes advantage of its minimal invasive condition to be applied to a wide variety of patients. We present five patients over 90 years of age who underwent successfully and without complications six therapeutic ERCPs. Endoscopic biliary sphincterotomy, common bile duct stone extraction and plastic stent insertion all were performed uneventfully and solving the biliary obstruction. Therapeutic ERCP is a safe and effective modality to treat bile duct obstruction in patients over 90 years of age.     

Cyclin D3 drives inertial cell cycling in dark zone germinal center B cells

During affinity maturation, germinal center (GC) B cells alternate between proliferation and somatic hypermutation in the dark zone (DZ) and affinity-dependent selection in the light zone (LZ). This anatomical segregation imposes that the vigorous proliferation that allows clonal expansion of positively selected GC B cells takes place ostensibly in the absence of the signals that triggered selection in the LZ, as if by “inertia.” We find that such inertial cycles specifically require the cell cycle regulator cyclin D3. Cyclin D3 dose-dependently controls the extent to which B cells proliferate in the DZ and is essential for effective clonal expansion of GC B cells in response to strong T follicular helper (Tfh) cell help. Introduction into the Ccnd3 gene of a Burkitt lymphoma–associated gain-of-function mutation (T283A) leads to larger GCs with increased DZ proliferation and, in older mice, clonal B cell lymphoproliferation, suggesting that the DZ inertial cell cycle program can be coopted by B cells undergoing malignant transformation.     

Nucleoprotein‐specific nonneutralizing antibodies speed up LCMV elimination independently of complement and FcγR

CD8⁺ T cells have an essential role in controlling lymphocytic choriomeningitis virus (LCMV) infection in mice. Here, we examined the contribution of humoral immunity, including nonneutralizing antibodies (Abs), in this infection induced by low virus inoculation doses. Mice with impaired humoral immunity readily terminated infection with the slowly replicating LCMV strain Armstrong but showed delayed virus elimination after inoculation with the faster replicating LCMV strain WE and failed to clear the rapidly replicating LCMV strain Docile, which is in contrast to the results obtained with wild‐type mice. Thus, the requirement for adaptive humoral immunity to control the infection was dependent on the replication speed of the LCMV strains used. Ab transfers further showed that LCMV‐specific IgG Abs isolated from LCMV immune serum accelerated virus elimination. These Abs were mainly directed against the viral nucleoprotein (NP) and completely lacked virus neutralizing activity. Moreover, mAbs specific for the LCMV NP were also able to decrease viral titers after transfer into infected hosts. Intriguingly, neither C3 nor Fcγ receptors were required for the antiviral activity of the transferred Abs. In conclusion, our study suggests that rapidly generated nonneutralizing Abs specific for the viral NP speed up virus elimination and thereby may counteract T‐cell exhaustion.     

Evaluation of a New Automated Homogeneous PCR Assay,GenomEra C. difficile,for Rapid Detection of Toxigenic Clostridium difficile in Fecal Specimens

We evaluated a new automated homogeneous PCR assay to detect toxigenic Clostridium difficile, the GenomEra C. difficile assay (Abacus Diagnostica, Finland), with 310 diarrheal stool specimens and with a collection of 33 known clostridial and nonclostridial isolates. Results were compared with toxigenic culture results, with discrepancies being resolved by the GeneXpert C. difficile PCR assay (Cepheid). Among the 80 toxigenic culture-positive or GeneXpert C. difficile assay-positive fecal specimens, 79 were also positive with the GenomEra C. difficile assay. Additionally, one specimen was positive with the GenomEra assay but negative with the confirmatory methods. Thus, the sensitivity and specificity were 98.8% and 99.6%, respectively. With the culture collection, no false-positive or -negative results were observed. The analytical sensitivity of the GenomEra C. difficile assay was approximately 5 CFU per PCR test. The short hands-on (<5 min for 1 to 4 samples) and total turnaround (<1 h) times, together with the high positive and negative predictive values (98.8% and 99.6%, respectively), make the GenomEra C. difficile assay an excellent option for toxigenic C. difficile detection in fecal specimens.     

Correlation of Pneumococcal Antibody Concentration and Avidity with Patient Clinical and Immunologic Characteristics

Purpose

The quality of an antibody response is determined by both the concentration and the strength of antigen-binding, or avidity, of the antibodies produced. Currently, only antibody concentration is routinely evaluated in the clinical assessment of humoral immunity. Here we studied correlations of avidities and concentrations of antibodies to pneumococcal polysaccharides with immunologic and clinical characteristics of patients with recurrent infections.

Methods

We measured concentration and avidity of antibodies to 12 pneumococcal serotypes in 78 children aged 0.6–18 years with recurrent bacterial respiratory infections, and in 80 individuals who were being tested for peanut allergy, ages 0.4–15 years, serving as a comparison group. Avidity was assessed by measuring antibody binding in the presence of thiocyanate.

Results

Antibody concentrations and avidities correlated positively for very few types contained in the conjugated pneumococcal vaccine (PCV7) in both patients and controls with some dependence on age; there were even fewer correlations for non-PCV7 types. Antibody concentrations and avidities negatively correlated with age for most of the PCV7 types. There was no consistent correlation of total IgG or IgG subclasses with either concentrations or avidities. Overall, antibody concentrations were higher and avidities were lower in patients compared to controls. Patients requiring chronic antibiotic use tended to have higher antibody concentrations and lower avidities for most serotypes than patients who did not. We identified several patients having many infections with apparent good antibody concentrations with low avidity for many types.

Conclusion

Antibody concentration and avidity correlate with patient clinical characteristics and distinguish patients from controls. Measurement of antibody avidity may provide another dimension for the clinical assessment of pneumococcal polysaccharide antibody response.