Flash behavior of femalePhoturis versicolor fireflies (Coleoptera: Lampyridae) in simulated courtship and predatory dialogues

FemalePhoturis versicolor fireflies attempt to capture males by responding to heterospecific flash patterns. A mating-dependent switch occurs which affects response timing and frequency of female flashes. We examined the switch using females of known age, mating status, and flash experience to assess how accurate mimicry is, what factors influence it, and what mechanism produces it. Presentations of simulated male flash patterns before and after mating revealed elements of an entrainment mechanism controlling female responsiveness. Unmated females preferentially answered conspecific patterns with variable latencies, averaging 1 s. Mating induced changes in both response frequency and response latency: Females answered heterospecific patterns more frequently, and latencies elicited by conspecific patterns shifted away from the unmated range. Heterogeneity in mean and variance of response latency among individuals indicates that females do not share a discrete reply to a given pattern. Little correspondence exists between latencies of sympatric species andP. versicolor females, suggesting that the flash response mechanism produces entriainment to any rhythmic pattern, not a one-to-one matching between prey and predator latencies. Different selective scenarios underlie strict mimicry versus entrainment mimicry.     

The amyloid beta peptide abeta (25-35) induces apoptosis independent of p53

Apoptosis of neuronal cells apparently plays a role in Alzheimer's disease (AD). The amyloid beta (Abeta) peptide derived from beta-amyloid precursor protein is found in AD brain in vivo and can induce apoptosis in vitro. While p53 accumulates in cells of AD brain, it is not known if p53 plays an active role in Abeta-induced apoptosis. We show here that inactivation of p53 in two experimental cell lines, either by expression of the papillomavirus E6 protein or by a shift to restrictive temperature, does not affect apoptosis induction by Abeta (25-35), indicating that Abeta induces apoptosis in a p53-independent manner.     

Effect of temperature on the formation and inactivation of syringomycin E pores in human red blood cells and bimolecular lipid membranes

The effects of temperature on the formation and inactivation of syringomycin E (SRE) pores were investigated with human red blood cells (RBCs) and lipid bilayer membranes (BLMs). SRE enhanced the RBC membrane permeability of 86Rb and monomeric hemoglobin in a temperature dependent manner. The kinetics of 86Rb and hemoglobin effluxes were measured at different temperatures and pore formation was found to be only slightly affected, while inactivation was strongly influenced by temperature. At 37 degrees C, SRE pore inactivation began 15 min after and at 20 degrees C, 40 min after SRE addition. At 6 degrees C, below the phase transition temperature of the major lipid components of the RBC membrane, no inactivation occurred for as long as 90 min. With BLMs, SRE induced a large current that remained stable at 14 degrees C, but at 23 degrees C it decreased over time while the single channel conductance and dwell time did not change. The results show that the temperature dependent inactivation of SRE pores is due to a decrease in the number of open pores.     

The application of the RT-PCR method for the staging of the prostate cancer progression

Molecular biology seems to bring more convincing markers for the detection of prostate cancer as well as the development of metastases than immunohistochemistry. The main goal of present work was to detect the expression of prostate specific antigen (PSA) and prostate-specific membrane antigen (PSM) genes in the micrometastases by the RT-PCR to assess the progression of prostate cancer. We analyzed 50 patients: 28 patients with clinically localized or locally advanced prostate cancer who underwent radical prostatectomy, 7 patients with clinically proven metastases, 8 patients with benign prostatic hyperplasia, and 7 healthy young men. The results of RT-PCR in the first group of 28 patients varied, however, they were in good correlation with the health status of the patients. Positive results of PSA and notably for PSM were good predictors of beginning metastasing process. Seven patients with metastatic disease had positive RT-PCR results both for PSA and PSM. All of the patients with benign prostatic hyperplasia and healthy young men had negative RT-PCR results for PSA and PSM. The study showed that positive RT-PCR results for PSA and especially for PSM correlated well with the progression of the disease and negative results reflected good health status of the patients.     

Regional differences of proliferation activity in the spinal cord ependyma of adult rats

Increased proliferation activity in the central canal ependyma of adult rodent spinal cord was described after injury and is thought to participate in recovery processes. Proliferation activity is scarce under physiological conditions, but still could be of importance, as in vitro studies showed that the spinal cord ependyma is an internal source of neural stem cells. Data from these studies indicate that there are regional differences in the distribution of proliferation activity along the rostro-caudal axis. We analyzed the proliferation activities in the ependyma within the entire extent of intact adult rat spinal cord. To identify proliferating cells we performed immunohistochemistry either for cell cycle S-phase marker BrdU or for the nuclear protein Ki-67. BrdU and Ki-67 positive cells were counted on sections selected from four spinal cord regions — cervical, thoracic, lumbar and sacral/coccygeal. Analysis showed that the number of BrdU positive cells within the ependyma was very low in all subdivisions of the spinal cord. Both BrdU and Ki-67 labeling revealed a significantly higher number of proliferating cells in the ependyma of sacrococcygeal part in comparison to all other spinal cord regions, suggesting that the caudal spinal cord might have potentially higher regeneration capacity compared to more rostral parts.     

Bile acid quantification of 20 plasma metabolites identifies lithocholic acid as a putative biomarker in Alzheimer’s disease

Introduction

There is still a clear need for a widely available, inexpensive and reliable method to diagnose Alzheimer’s disease (AD) and monitor disease progression. Liquid chromatography–mass spectrometry (LC-MS) is a powerful analytic technique with a very high sensitivity and specificity.

Objectives

The aim of the present study is to measure concentrations of 20 bile acids using the novel Kit from Biocrates Life Sciences based on LC-MS technique.

Methods

Twenty bile acid metabolites were quantitatively measured in plasma of 30 cognitively healthy subjects, 20 patients with mild cognitive impairment (MCI) and 30 patients suffering from AD.

Results

Levels of lithocholic acid were significantly enhanced in plasma of AD patients (50?±?6 nM, p?=?0.004) compared to healthy controls (32?±?3 nM). Lithocholic acid plasma levels of MCI patients (41?±?4 nM) were not significantly different from healthy subjects or AD patients. Levels of glycochenodeoxycholic acid, glycodeoxycholic acid and glycolithocholic acid were significantly higher in AD patients compared to MCI patients (p?<?0.05). All other cholic acid metabolites were not significantly different between healthy subjects, MCI patients and AD patients. ROC analysis shows an overall accuracy of about 66%. Discriminant analysis was used to classify patients and we found that 15/23 were correctly diagnosed. We further showed that LCA levels increased by about 3.2 fold when healthy subjects converted to AD patients within a 8–9 year follow up period. Pathway analysis linked these changes to a putative toxic cholesterol pathway.

Conclusion

In conclusion, 4 bile acids may be useful to diagnose AD in plasma samples despite limitations in diagnostic accuracy.

     

Oenothera chloroplast DNA polymorphisms associated with plastome mutator activity

Molecular Genetics and Genomics - Oenothera plants homozygous for a recessive allele at the plastome mutator (pm) locus show non-Mendelian mutation frequencies that are 1000-fold higher than...     

Common definition for categories of clinical research: a prerequisite for a survey on regulatory requirements by the European Clinical Research Infrastructures Network (ECRIN)

Background

Idiopathic recurrent miscarriage is defined as 3 consecutive pregnancy losses with no contributing features found on investigations. At present there are no treatments of proven efficacy for idiopathic recurrent miscarriage. Uterine natural killer (uNK) cells, the most predominant leucocyte in the endometrium are adjacent to foetal trophoblast cells and thought to be involved in implantation. The exact mechanisms of how uNK cells affect implantation are not clear but are probably through the regulation of angiogenesis. Multiple studies have shown an association between high density of uterine natural killer cells and recurrent miscarriage. We have shown that prednisolone reduces the number of uNK cells in the endometrium. The question remains as to whether reducing the number of uNK cells improves pregnancy outcome.

Methods

We propose a randomised, double-blind, placebo controlled trial of prednisolone with a pilot phase to assess feasibility of recruitment, integrity of trial procedures, and to generate data to base future power calculations. The primary aim is to investigate whether prednisolone therapy during the first trimester of pregnancy is able to improve live birth rates in patients with idiopathic recurrent miscarriage and raised uNK cells in the endometrium. Secondary outcomes include conception rate, karyotype of miscarriage, miscarriages (first and second trimester), stillbirths, pregnancy complications, gestational age at delivery, congenital abnormality and side effects of steroids. The trial has 2 stages: i) screening of non-pregnant women and ii) randomisation of the pregnant cohort. All patients who fit the inclusion criteria (<40 years old, ≥3 consecutive miscarriages with no cause found and no contraindications to prednisolone therapy) will be asked to consent to an endometrial biopsy in the mid-luteal phase to assess their levels of uNK cells. Women with high levels of uNK cells (≥5%), will be randomised to either prednisolone or placebo when a pregnancy is confirmed. Follow-up includes 2 weekly ultrasound scans in the first trimester, an anomaly scan at 20 weeks gestation, growth scans at 28 and 34 weeks gestation and a postnatal follow-up at 6 weeks.

Trial Registration

Current Controlled Trials ISRCTN28090716