Influence of Growth Conditions on the Production of a Bacteriocin, Pediocin AcH, by Pediococcus acidilactici H

The influence of growth parameters on the production of pediocin AcH by Pediococcus acidilactici H was studied. This strain produced large quantities of pediocin AcH in TGE broth (Trypticase [1%], glucose [1%], yeast extract [1%], Tween 80 [0.2%], Mn [0.033 mM], Mg [0.02 mM] [pH 6.5]) within 16 to 18 h at 30 to 37 degrees C (final pH, 3.6 to 3.7). Pediocin AcH production was negligible when the pH of the medium was maintained at 5.0 or above, even in the presence of high cell mass.

Hydrostatic pressure and electroporation have increased bactericidal efficiency in combination with bacteriocins

We report here that both ultrahigh hydrostatic pressure (UHP) and electroporation (EP) induced sublethal injury to bacterial cells surviving the treatments. The injured cells of both gram-positive and -negative bacteria became sensitive to the bacteriocins pediocin AcH and nisin. Bacteriocins in combination with either UHP or EP have greater antibacterial effectiveness than UHP or EP alone.

The outcome of expectant management of congenital cystic adenomatoid malformations (CCAM) of the lung

INTRODUCTION

The appropriate management of asymptomatic congenital cystic adenomatoid malformations of the lung (CCAM) remains controversial. The aim of this study is to determine the outcome of expectant management of these lesions and the sensitivity of antenatal ultrasound diagnosis.

MATERIAL AND METHODS

A retrospective review was undertaken of all cases identified from prospectively collected databases with an antenatal or postnatal diagnosis of CCAM in the Northern region of England between 1985 and 2006 where such lesions underwent resection only when symptomatic.

RESULTS

Thirty-seven cases of confirmed CCAM were identified antenatally or postnatally. Twenty-six (70%) were identified by antenatal ultrasound scans (during a period of near-universal antenatal scanning), of whom 21 (81%) were liveborn. In total, 16 of 29 (55%) liveborn infants with CCAM were symptomatic, and either died within the first postnatal week or underwent resection. Thirteen (45% of livebirths) were managed expectantly and remained asymptomatic. The sensitivity of antenatal ultrasound screening for CCAM increased over the period to 90% in the latter half of the study (p=0.035), although the positive predictive value (66%) did not improve.

CONCLUSIONS

Expectant management was a reasonable option for almost half of the babies, but over one third required surgery for CCAM, most becoming symptomatic in infancy. In view of the uncertainty that surrounds decisions regarding expectant or pre-emptive resection in asymptomatic infants, the authors advocate having an open and honest discussion when counselling parents (particularly antenatally) regarding surveillance or expectant management as a reasonable strategy.

Memantine lowers amyloid-beta peptide levels in neuronal cultures and in APP/PS1 transgenic mice

Memantine is a moderate-affinity, uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist that stabilizes cognitive, functional, and behavioral decline in patients with moderate to severe Alzheimer's disease (AD). In AD, the extracellular deposition of fibrillogenic amyloid-beta peptides (Abeta) occurs as a result of aberrant processing of the full-length Abeta precursor protein (APP). Memantine protects neurons from the neurotoxic effects of Abeta and improves cognition in transgenic mice with high brain levels of Abeta. However, it is unknown how memantine protects cells against neurodegeneration and affects APP processing and Abeta production. We report the effects of memantine in three different systems. In human neuroblastoma cells, memantine, at therapeutically relevant concentrations (1-4 muM), decreased levels of secreted APP and Abeta(1-40). Levels of the potentially amylodogenic Abeta(1-42) were undetectable in these cells. In primary rat cortical neuronal cultures, memantine treatment lowered Abeta(1-42) secretion. At the concentrations used, memantine treatment was not toxic to neuroblastoma or primary cultures and increased cell viability and/or metabolic activity under certain conditions. In APP/presenilin-1 (PS1) transgenic mice exhibiting high brain levels of Abeta(1-42), oral dosing of memantine (20 mg/kg/day for 8 days) produced a plasma drug concentration of 0.96 microM and significantly reduced the cortical levels of soluble Abeta(1-42). The ratio of Abeta(1-40)/Abeta(1-42) increased in treated mice, suggesting effects on the gamma-secretase complex. Thus, memantine reduces the levels of Abeta peptides at therapeutic concentrations and may inhibit the accumulation of fibrillogenic Abeta in mammalian brains. Memantine's ability to preserve neuronal cells against neurodegeneration, to increase metabolic activity, and to lower Abeta level has therapeutic implications for neurodegenerative disorders.

Ovarian folliculogenesis: detrimental effect of prenatal exposure to cyclophosphamide: a preliminary study

AIM

To investigate whether cyclophosphamide interferes with ovarian folliculogenesis.

METHODS

In this experiment, pregnant rats (n=12) were randomly assigned into two groups, control group (n=6) and cyclophosphamide treatment group (n=6). In the cyclophosphamide treatment group cyclophosphamide was injected intraperitoneally from day 10 of gestation till 20th day, at 2 mg/kg of body weight. The pregnant rats were sacrificed on gestation day 20 and the fetus was collected. The collected fetuses were processed for sectioning and stained with haematoxyline and eosin for microscopic observation of the ovaries.

RESULTS

A meshwork-like appearance of mesenchyme with decreased number of somatic cells and absence of the majority of the germ cells in the ovarian follicles were found in treated fetus. Non-availability of primordial germ cells stopped the interaction between primordial germ cells and somatic supporting cells leading to nonproliferation and degeneration of somatic cells and fluid-filled vacant spaces in the meshwork -like arrangement of mesenchymal cells.

CONCLUSION

We conclude that cyclophosphamide exposure prevents folliculogenesis by causing anovulation and results in infertility. The same detrimental effect might be seen in human fertility with environmental pollutants which are also metabolites of the drug (Fig. 2, Ref. 25).

Memantine treatment decreases levels of secreted Alzheimer's amyloid precursor protein (APP) and amyloid beta (A beta) peptide in the human neuroblastoma cells

Memantine, an uncompetitive NMDA receptor antagonist, is a FDA-approved drug used for the treatment of moderate-to-severe Alzheimer's disease (AD). Several studies have documented protective roles of memantine against amyloid beta (A beta) peptide-mediated damage to neurons in both in vitro and in vivo models. Memantine is also effective in reducing amyloid burden in the brain of APP transgenic mice. However, the exact mechanism by which memantine provides protection against A beta-mediated neurodegenerative cascade, including APP metabolism, remains to be elucidated. Herein, we investigated the effect of memantine on levels of the secreted form of A beta precursor protein (APP), secreted A beta and cell viability markers under short/acute conditions. We treated neuronal SK-N-SH cells with 10 microM memantine and measured levels of secreted total APP (sAPP), APP alpha isoform and A beta((1-40)) in a time dependent manner for up to 24h. Memantine significantly decreased the levels of the secreted form of sAPP, sAPP alpha and A beta((1-40)) compared to vehicle treated cells. This change started as early as 8h and continued for up to 24h of drug treatment. Unlike sAPP, a slight non-significant increase in total intracellular APP level was observed in 24-h treated memantine cells. Taken together, these results suggest a role for memantine in the transport or trafficking of APP molecules away from the site of their proteolytic cleavage by the secretase enzymes. Such a novel property of memantine warrants further study to define its therapeutic utility.

Determination of high-affinity choline uptake (HACU) and choline acetyltransferase (ChAT) activity in the same population of cultured cells

Cholinergic neurons are a major constituent of the mammalian central nervous system. Acetylcholine, the neurotransmitter used by cholinergic neurons, is synthesized from choline and acetyl CoA by the enzymatic action of choline acetyltransferase (ChAT). The transport of choline into the cholinergic neurons, which results in synthesis of ACh, is hemicholinium-sensitive and is referred to as high-affinity choline uptake (HACU). Thus, the formation of acetylcholine in cholinergic neurons largely depends on both the levels of choline being transported into the cells from the extracellular space and the activity of ChAT. Several methods were described previously to measure HACU and ChAT simultaneously in synaptosomes, but the same for cultured cells is lacking. We describe a procedure to measure HACU and ChAT at the same time in cultured cells by simple techniques employing radionuclides. In this procedure, we determined quantitatively hemicholinium-sensitive choline uptake and ChAT enzyme activity in a small number of differentiated human neuroblastoma (SK-N-SH) cells. We also determined the kinetics of choline uptake in the SK-N-SH cells. We believe that these simple methods can be used for neurochemical and drug discovery studies in several models of neurodegenerative disorders including Alzheimer's disease.

Molecular and immunocytochemical characterization of primary neuronal cultures from adult rat brain: Differential expression of neuronal and glial protein markers

Neurobiological studies using primary neuronal cultures commonly employ fetal-derived neurons, but much less often adult brain-derived neurons. Our goal is to perform morphological and molecular characterization of primary neuronal cultures from adult rat brain, including the relative expression of neuronal and glial cell markers at different time points. We tested the hypothesis that long-term neuronal viability is compatible with glial proliferation in adult neuron culture. We examined neuron culture from adult rat brain, which was maintained at steady state up to 24 days, and characterized them on the basis of cellular, molecular and biochemical properties at different time points of the culture. We identified neuronal and glial cells by both immunocytochemical and western immunoblotting techniques using NSE and Tau as neuronal markers and GFAP as glial protein marker, which revealed the presence of predominantly neuronal cells in the initial phase of the culture and a rise in glial cells from day 12 onwards. Notably, neuronal cells were preserved in the culture along with the glial cells even at day 24. Transfection of the cultured cells with a GFP expression vector and plasmids containing a luciferase reporter gene under the control of two different gene promoters demonstrated DNA transfectability. Taken together, these results suggest a differential expression of neuronal and glial cells at different time points and long-term neuronal viability in the presence of glial proliferation. Such adult neurons serve as a suitable system for the application of neurodegeneration models and for drug target discovery in various brain disorders including Alzheimer's disease.

Mortality of twin and singleton livebirths under 30 weeks' gestation: a population-based study

OBJECTIVE

To determine the mortality rates of liveborn twins compared with singletons of less than 30 weeks' gestation in relation to gestational age, mode of delivery and year of birth in a geographically defined population.

STUDY DESIGN

Comparison of early neonatal, late neonatal and infant death rates in 479 twin babies and 1538 singletons, liveborn between 23 and 29 completed weeks of gestation in the north of England over two epochs, 1998-2001 and 2002-5.

RESULTS

Twins and singletons had similar mortality rates except at the extreme of gestation (23-25 weeks) where twins had higher infant mortality (OR 2.04, 95% CI 1.37 to 3.02). This higher rate was attributable to early and late neonatal deaths (OR 1.86, 95% CI 1.28 to 2.72, and 2.11, 95% CI 1.13-3.94, respectively). When analysed in two epochs, the excess mortality was confined to babies born in 1998-2001. There was no effect of gender or chorionicity.

CONCLUSIONS

The excess mortality among twins of less than 30 weeks' gestation was confined to neonatal deaths in babies of 25 weeks or less, and to the earlier epoch (1998-2001). In the modern era, there appears to be no excess mortality in neonates less than 30 weeks' gestation when compared with singletons.

Plasma tissue factor is a predictor for restenosis after femoropopliteal angioplasty

Background

In vitro studies suggest an association between raised levels of tissue factor and restenosis after coronary percutaneous transluminal angioplasty (PTA). This prospective, controlled study examined the association between plasma tissue factor concentrations and restenosis after femoropopliteal PTA.

Methods

Plasma samples from ten healthy controls and 36 patients with unilateral claudication undergoing femoropopliteal PTA were collected at baseline and, in the patients with claudication, at 24 h and 1, 3 and 6 months after PTA. Clinical assessment and arterial duplex imaging were performed before and at the same time points after PTA to identify restenosis. Plasma tissue factor was measured using a specific enzyme-linked immunosorbent assay.

Results

Baseline plasma tissue factor concentrations were significantly higher in patients with claudication (median 3·4 (interquartile range (i.q.r.) 1·3–7·4) ng/ml) than in controls (median 1·2 (i.q.r. 0·5–1·8) ng/ml) (P < 0·050). Baseline tissue factor concentrations were significantly higher in the ten patients with claudication who developed restenosis after PTA (median 7·0 (i.q.r. 3·4–183·5) ng/ml) than in those who did not (median 1·7 (i.q.r. 1·3–7·2) ng/ml) (P < 0·050). In addition, plasma tissue factor levels increased significantly over time in the patients who developed restenosis after PTA.

Conclusion

High baseline and progressive increases in the plasma tissue factor concentration were useful predictors of restenosis after femoropopliteal angioplasty.

A Non-randomised Controlled Trial of the Clinical and Cost Effectiveness of a Supervised Exercise Programme for Claudication

OBJECTIVES

The main aims of treatment in patients with intermittent claudication (IC) are to improve the clinical indicators of lower limb ischaemia and patients' quality of life (QoL). The aims of this study were assess the clinical and cost effectiveness of a supervised exercise programme (SEP) in patients with IC.

DESIGN

Non-randomised, controlled trial.

SETTING

University teaching hospital.

PATIENTS AND METHODS

Two groups of patients with IC were studied. Seventy patients were sequentially recruited before and after the establishment of a Supervised Exercise Programme at our unit. Thirty-seven patients (median age 69 years, 26 men) received conservative medical therapy (CMT) and 33 patients (median age 67 years, 22 men) received CMT plus a 3 month SEP of graduated physical exercise for sixty minutes, three times each week. Patients were assessed prior to and at 6 months following treatment. At each assessment patient reported walking distances (PRWD), treadmill claudication and maximal distances (ICD and MWD), ankle brachial pressure indices (ABPI) pre & post exercise and patient reported QoL using the SF36 questionnaire were assessed.

RESULTS

Prior to intervention the two groups were well matched. Following treatment, CMT patients demonstrated no significant change in PRWD or ICD but did record a small but significant improvement in MWD. CMT was also associated with a negative effect size in the SF36 index and in 7 of the 8 SF36 QoL domains, effect size >-0.5 for the domains of Physical Function and Emotional Role. SEP patients demonstrated significant improvement in PRWD, ICD and MWD. SEP was associated with a positive effect size in the SF36 index and in 2 SF36 QoL domains but a negative effect size in a further 2 domains. However, all QoL effect sizes following SEP were < +/-0.5. Intergroup differences in effect sizes were >0.5 for the SF36 domains of Physical Function, Physical Role, Emotion Role and SF36 index. SEP resulted in a 0.027 quality adjusted life year (QALY) gain over CMT in the first year post-treatment thus the cost/QALY gained of SEP is pound1780 at 1 year.

CONCLUSIONS

Compared to CMT, SEP increases walking distances, improves QoL and is a highly cost-effective treatment for IC.

Formation of density waves in traffic flow through intersecting roads

The formation of density waves in two intersecting roads, with a traffic circle at the intersection, is studied. It is found that, depending on the traffic densities in the two roads, density waves can form in the traffic circle and in one or both of the roads. Depending on the expression chosen for the optimal velocity, either the congestion moves entirely to the traffic circle or the congestion becomes confined to the traffic circle and a part of the road approaching the traffic circle.