Analysis of LMNB1 Duplications in Autosomal Dominant Leukodystrophy Provides Insights into Duplication Mechanisms and Allele‐Specific Expression

Autosomal dominant leukodystrophy (ADLD) is an adult onset demyelinating disorder that is caused by duplications of the lamin B1 (LMNB1) gene. However, as only a few cases have been analyzed in detail, the mechanisms underlying LMNB1 duplications are unclear. We report the detailed molecular analysis of the largest collection of ADLD families studied, to date. We have identified the minimal duplicated region necessary for the disease, defined all the duplication junctions at the nucleotide level and identified the first inverted LMNB1 duplication. We have demonstrated that the duplications are not recurrent; patients with identical duplications share the same haplotype, likely inherited from a common founder and that the duplications originated from intrachromosomal events. The duplication junction sequences indicated that nonhomologous end joining or replication‐based mechanisms such fork stalling and template switching or microhomology‐mediated break induced repair are likely to be involved. LMNB1 expression was increased in patients’ fibroblasts both at mRNA and protein levels and the three LMNB1 alleles in ADLD patients show equal expression, suggesting that regulatory regions are maintained within the rearranged segment. These results have allowed us to elucidate duplication mechanisms and provide insights into allele‐specific LMNB1 expression levels.     

The dependency of bioactive follicle-stimulating hormone secretion on gonadotropin-releasing hormone in hypogonadal and cycling women

An antagonist analog of GnRH, (Ac-delta 3-Pro1,p-F-D-Phe2,D-Trp3,6)GnRH (4F-antagonist), was administered to normal women and women with hypergonadotropic hypogonadism. Serum FSH levels were determined by both the granulosa cell aromatase bioassay and RIA. The constant infusion of 4F-antagonist (30 micrograms/kg.h) to the four hypogonadal women resulted in a more pronounced decline in bioactive FSH (62%) than in immunoreactive FSH levels (30%), and the FSH bioactive to immunoreactive ratio decreased significantly (P less than 0.05). Infusion of 4F-antagonist in normal women in the midfollicular phase revealed a similar pattern of suppression of bioactive (64%) and immunoreactive FSH (29%). When 4F-antagonist was administered sc at a dose of 80 micrograms/kg twice daily for 3 days to normal women in the midfollicular phase of their cycles, the bioactive FSH response was biphasic, with the maximal decrease on the second day, followed by return to basal levels on the third day. Correspondingly, there was a precipitous decline in serum estradiol (apparent demise of the dominant follicle), followed by a progressive rise in estradiol levels. Thus, in contrast to immunoreactive FSH levels, bioactive FSH more clearly reflects the biological action of FSH on the follicle in response to GnRH antagonist administration in women. The disparity in the quantitative decline between serum bioactive and immunoreactive FSH levels after presumed blockade of the GnRH receptor may reflect the microheterogeneity of the FSH molecule and suggests that alterations in the biological activity of secreted FSH may be GnRH dependent.     

Left ventricular mass regression in the LIFE study: effect of previous antihypertensive treatment

BACKGROUND: Whether to include only those patients who have not had prior hypertension treatment in clinical trials of left ventricular (LV) mass reduction is controversial. Accordingly, our aim was to study the relationship between prior treatment and both baseline and 1-year echocardiographic LV mass in subjects enrolled in the Losartan Intervention For Endpoint reduction (LIFE) study. METHODS: We studied clinical and baseline echocardiographic data on 960 patients with electrocardiographically confirmed left ventricular hypertrophy enrolled in the electrocardiographic substudy of the LIFE study, 847 of whom had LV mass remeasured after 1 year of blinded treatment. The majority (75%) of these patients had prior medical treatment for hypertension. RESULTS: In multivariable regression analysis, controlling for age, sex, blood pressure (BP), body mass index, and indices of pump and myocardial function, prior antihypertensive treatment was not associated with either greater LV mass or relative wall thickness on the baseline study. Moreover, there was no significant difference between the 637 subjects who were previously treated and the 210 who were not treated with regard to the mean reduction in systolic or diastolic pressures (-25 +/- 17 v -24 +/- -16 and -13 +/- 9 mm Hg v -12 +/- 9 mm Hg), LV mass (-27 +/- 38 v -29 +/- 34 g), or LV mass/body surface area (-14 +/- 20 v -15 +/- 18 g/m(2)), all P >.05. CONCLUSIONS: Prior treatment is not associated with either greater LV mass or greater relative wall thickness when age, body mass index, sex, systolic BP, heart rate, or indices of LV volume load and systolic function are taken into account. In addition, prior treatment is not associated with lesser degrees of LV mass reduction. For design of future clinical trials, restriction of inclusion criteria to only previously untreated patients does not appear to be necessary when the selection criterion is electrocardiographically determined left ventricular hypertrophy.     

Acid production and growth by oral Lactobacillus species in vitro

Aim: To analyze the acid‐producing and growth abilities of different oral Lactobacillus species. Methods: Thirty‐nine oral clinical strains and type strains of Lactobacillus, representing nine species, including Lactobacillus casei/paracasei, Lactobacillus fermentum, Lactobacillus gasseri, Lactobacillus mucosae, Lactobacillus oris, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus salivarius, and Lactobacillus vaginalis were studied. Anaerobically‐grown bacterial cells were inoculated overnight in de Man, Rogosa, and Sharpe broth containing 2% glucose (pH 7.0). Acid production and growth were measured at 0, 1.5, 3, 5, 7, and 24 h. Results: Lactobacillus salivarius, Lactobacillus rhamnosus, Lactobacillus casei/paracasei, and Lactobacillus plantarum grew rapidly and reached an optical density higher than other species. They also produced more acid than the others. Lactobacillus vaginalis showed the lowest rate of growth and acid production. These findings demonstrated that the different species of Lactobacillus showed different abilities to generate acid, allowing the species to be categorized into three groups: strongly, moderately, and weakly acidogenic. Conclusion: There was variation in acid production and growth between the Lactobacillus species. The strongest acid producers were Lactobacillus salivarius, Lactobacillus rhamnosus, Lactobacillus plantarum, and Lactobacillus casei/paracasei, respectively. It seems possible that these species might play a more important role in caries development than the others.     

Thrombocytosis and venous thromboembolism in cancer patients with chemotherapy induced anemia may be related to ESA induced iron restricted erythropoiesis and reversed by administration of IV iron

ESA therapy can increase hemoglobin, decrease blood transfusions, and improve quality of life in patients with chemotherapy induced anemia (CIA). Despite its benefits, ESA therapy increases the risk of venous thromboembolism (VTE) in cancer patients by 50% and can also cause iron restricted erythropoiesis in CIA patients, which may augment the tendency to develop VTE. We postulated that thrombocytosis, a risk factor for VTE in cancer patients, in CIA patients on ESA therapy might be a result of ESA induced iron restricted erythropoiesis. We performed a retrospective analysis of 187 CIA patients who were randomized to receive weekly Epoetin and IV ferric gluconate, oral ferrous sulfate, or no iron for 8 weeks. Nineteen patients experienced 29 VTEs, and patients, whose platelets increased to ≥350,000 cells/uL were three times more likely to experience a VTE (OR 2.9, P = 0.036, logistic regression) with a four times greater incidence of VTE (IRR 4.4, P = 0.001, Poisson regression). Patients treated with IV iron were significantly less likely to develop platelets of ≥350,000 cells/uL (IRR 0.7, P = 0.013, Poisson regression) and had a decreased incidence of VTE. Our study suggests that ESA associated VTE in CIA patients may be, in part, related to the thrombocytosis of ESA induced iron restricted erythropoiesis and may be countered by IV iron.