Equine parasite control and the role of national legislation - A multinational questionnaire survey.

Experts recommend a change in the control of equine parasites across the world in order to adopt a surveillance-based approach utilizing parasite faecal egg counts (FEC). Several European countries have implemented prescription-only restrictions of anthelmintic usage by law, which is in stark contrast to US, where all anthelmintic products continue to be available over the counter. This study aimed to describe and compare equine parasite control strategies employed in Germany, Austria, the Netherlands, US, and Denmark. An invitation to participate in an online questionnaire survey was published on a large equine news website in each of the participating countries. The main focus of the study was on usage of FEC and anthelmintic treatment intensity in three different equine age groups; foals, 1-3 year-olds and >3 years old. A total of 3092 respondents participated in the study. Danish respondents used significantly more faecal analyses in their parasite control strategies than participants from the other four countries (p < 0.0001). Similarly, Danish participants administered significantly fewer anthelmintic treatments per horse per year (p < 0.0001) independent of the age of the horse, and had been using a selective treatment strategy for a significantly longer time period than their counterparts in other countries (p < 0.0001). Only minor differences were found between respondents from the other four countries. This is remarkable as both Austria and Germany have had prescription-only restrictions for 3-4 decades. Yet, their parasite control strategies were more similar to those employed by American respondents. The Netherlands had only recently introduced prescription-only restrictions by the time this survey was conducted which can explain why Dutch respondents were also similar to their American counterparts. Taken together, this study illustrates substantially different worm control strategies practiced in Denmark, and this difference cannot be explained by legislation alone.

Irritable bowel syndrome: an integrated explanatory model for clinical practice.

BACKGROUND: Although irritable bowel syndrome (IBS) is a symptom-based diagnosis, clinicians' management of and communication about the disorder is often hampered by an unclear conceptual understanding of the nature of the problem. We aimed to elucidate an integrated explanatory model (EM) for IBS from the existing literature for pragmatic use in the clinical setting. METHODS: Systematic and exploratory literature searches were performed in PubMed to identify publications on IBS and EMs. KEY RESULTS: The searches did not identify a single, integrated EM for IBS. However, three main hypotheses were elucidated that could provide components with which to develop an IBS EM: (i) altered peripheral regulation of gut function (including sensory and secretory mechanisms); (ii) altered brain-gut signaling (including visceral hypersensitivity); and (iii) psychological distress. Genetic polymorphisms and epigenetic changes may, to some degree, underlie the etiology and pathophysiology of IBS and could increase the susceptibility to developing the disorder. The three model components also fit into one integrated explanation for abdominal symptoms and changes in stool habit. Additionally, IBS may share a common pathophysiological mechanism with other associated functional syndromes. CONCLUSIONS & INFERENCES: It was possible to elucidate an integrated, three-component EM as a basis for clinicians to conceptualize the nature of IBS, with the potential to contribute to better diagnosis and management, and dialog with sufferers.

Immunolocalization of the cholesterol transporters ABCA1 and ABCG1 in canine reproductive tract tissues and spermatozoa.

The mammalian sperm membrane undergoes cholesterol efflux during maturation and fertilization. Although ATP-binding cassette (ABC) transporters are known to transport cholesterol through cell membranes in other organs, their presence in canine testis, epididymis and sperm has not been proven to date. Hence, the aim of the present study was to localize the ABC transporters ABCA1 and ABCG1 in canine testicular and epididymidal tissue as well as in spermatozoa membranes. To this end, semen samples from 12 dogs as well as testicles and epididymides of four young and healthy dogs were prepared for immunohistochemistry, respectively. Capacitation and acrosome reaction (AR) were induced in aliquots of the semen samples before immunostaining to assess changes in the expression of ABCA1 and ABCG1. Evaluation by confocal microscopy revealed the presence of both ABCA1 and ABCG1 in canine testicles and of ABCA1 in the epididymides. In spermatozoa, only ABCA1 immunoreactivity was detected, mainly in the region of the acrosome and midpiece. After induction of capacitation, ABCA1 signal persisted in the acrosome but disappeared after AR, indicating a loss of ABCA1 with the loss of the acrosome. We conclude that ABCA1 and ABCG1 are expressed in canine testis, whereas only ABCA1 is expressed in epididymis and spermatozoa membrane, both transporters probably contributing to the regulation of membrane cholesterol content.

Equine parasite control under prescription-only conditions in Denmark--awareness, knowledge, perception, and strategies applied.

Due to widespread development of anthelmintic resistance in equine parasites, recommendations for their control are currently undergoing marked changes with a shift of emphasis toward more coprological surveillance and reduced treatment intensity. Denmark was the first nation to introduce prescription-only restrictions of anthelmintic drugs in 1999, but other European countries have implemented similar legislations over recent years. A questionnaire survey was performed in 2008 among Danish horse owners to provide a current status of practices and perceptions with relation to parasite control. Questions aimed at describing the current use of coprological surveillance and resulting anthelmintic treatment intensities, evaluating knowledge and perceptions about the importance of various attributes of parasite control, and assessing respondents' willingness to pay for advice and parasite surveillance services from their veterinarians. A total of 1060 respondents completed the questionnaire. A large majority of respondents (71.9%) were familiar with the concept of selective therapy. Results illustrated that the respondents' self-evaluation of their knowledge about parasites and their control associated significantly with their level of interest in the topic and their type of education (P<0.0001). The large majority of respondents either dewormed their horses twice a year and/or performed two fecal egg counts per horse per year. This approach was almost equally pronounced in foals, horses aged 1-3 years old, and adult horses. The respondents rated prevention of parasitic disease and prevention of drug resistance as the most important attributes, while cost and frequent fecal testing were rated least important. Respondents' actual spending on parasite control per horse in the previous year correlated significantly with the amount they declared themselves willing to spend (P<0.0001). However, 44.4% declared themselves willing to pay more than what they were spending. Altogether, results indicate that respondents were generally familiar with equine parasites and the concept of selective therapy, although there was some confusion over the terms small and large strongyles. They used a large degree of fecal surveillance in all age groups, with a majority of respondents sampling and/or treating around twice a year. Finally, respondents appeared willing to spend money on parasite control for their horses. It is of concern that the survey suggested that foals and young horses are treated in a manner very similar to adult horses, which is against current recommendations. Thus, the survey illustrates the importance of clear communication of guidelines for equine parasite control.

Establishment of a practical sperm penetration test for bovine semen.

OBJECTIVE: Several methods for evaluating semen quality have been developed in addition to traditional semen analysis. Most of these methods are very complex and require expensive technical equipment as well as special knowledge to be performed. The aim of this study was to establish an easy and cost-effective sperm penetration test for bovine semen using artificial media. Additionally a standard procedure for test performance should be figured out. MATERIAL AND METHODS: In the first part of the study four different capillary tubes or pipettes were evaluated in order to determine the most appropriate one to use in the penetration test. In the second part of the study the tubes were filled with different compositions of polyacrylamide gel and subsequently incubated at 37.5 °C for 30 minutes. Sperm penetration was then evaluated using a phase contrast microscope, measuring the penetration distance of the first, the first motile and the five vanguard motile spermatozoa as well as determining the number of sperm cells cumulated per low power field (LPF) at three distinct distances in the tube. RESULTS: Non-heparinised haematocrit capillary tubes were the most appropriate tubes for performance of sperm penetration test as 100% of used capillaries were evaluable after incubation and size of the capillaries allowed a simple handling and good visualisation of migrated spermatozoa. Best results were achieved with 1.9% polyacrylamide gel containing phosphate-buffered saline. Measuring the penetration distance of the vanguard motile sperm cell can be recommended for test evaluation. CONCLUSION: A sperm penetration test with 1.9% polyacrylamide using non-heparinised capillary tubes was established. Results showed high reproducibility, the procedure is simple to carry out and only requires a phase contrast microscope.

Physiological and behavioral stress parameters in calves in response to partial scrotal resection, orchidectomy, and Burdizzo castration.

Establishing artificial cryptorchids by partial scrotal resection without removing the testicles is a technique for castration of bull calves that recently has gained new interest. In contrast to orchidectomy and Burdizzo castration, the stress response of calves to shortening of the scrotum is unknown. In this study, partial scrotal resection in bull calves was compared with orchidectomy, Burdizzo castration, and controls without intervention (n=10 per group, ages 56 ± 3 d). Procedures were performed under xylazine sedation and local anesthesia. We hypothesized that partial scrotal resection is least stressful. Salivary cortisol, heart rate, heart rate variability, behavior, and locomotion were analyzed. Cortisol concentration peaked 60 min after start of the procedures. Cortisol release was at least in part xylazine induced and none of the experimental procedures released additional cortisol. Heart rate increased in calves of all groups with initial handling, but immediately after xylazine sedation decreased to 30% below initial values and was not modified by surgical procedures. The heart rate variability variables standard deviation of beat-to-beat interval and root mean square of successive beat-to-beat differences increased when calves were placed on the surgery table but effects were similar in calves submitted to surgeries and control calves. Locomotion increased, whereas lying time decreased in response to all surgeries. Locomotion increase was most pronounced after orchidectomy. Plasma fibrinogen concentrations increased after orchidectomy only. With adequate pain medication, orchidectomy, Burdizzo castration, and partial scrotal resection do not differ with regard to acute stress and, by inference, pain. Partial scrotal resection when carried out under xylazine sedation and local anesthesia thus is an acceptable castration technique in bull calves.

Cooled storage of canine semen: in vitro effects of different concentrations of an antibiotic combination on growth of mollicutes.

The aim of this study was to examine effects of an antibiotic combination at different concentrations on growth of mycoplasma and ureaplasma during cooled storage of canine semen (n = 20). Semen aliquots were diluted with Tris-citric acid-fructose-egg yolk extender containing either 1.0 g/l streptomycin and 0.6 g/l benzylpenicillin (control) or a combination of gentamycin, tylosin, lincomycin and spectinomycin (GTLS-1: 0.25, 0.05, 0.15 and 0.3; GTLS-2: 0.5, 0.1, 0.3 and 0.6; GTLS-3: 1.0, 0.2, 0.6 and 1.2 g/l). Samples were assessed for motility and membrane integrity by computer-assisted sperm analysis immediately after dilution and at 24, 48 and 72 h of cooled storage. Morphologically, normal spermatozoa were determined, and bacterial culture was performed at 24 and 72 h. Mycoplasma spp. were detected in 14 of 20 ejaculates (70%) with severe growth in 12 samples. A reduction but not total elimination of mycoplasma growth occurred in all GTLS extenders with the most pronounced reduction in group GTLS-3 (control vs GTLS-1 and GTLS-2 p < 0.05, control vs GTLS-3 p < 0.001). Ureaplasmas were detected in four ejaculates, and growth was reduced to the same extent in GTLS and control extender. Progressive motility in all groups, total motility in groups GTLS 1-3 and percentage of membrane-intact spermatozoa in groups GTLS 2 and 3 decreased slightly (p < 0.05) over time. In conclusion, dilution of canine semen with GTLS extender has no major detrimental effects on spermatozoa during cooled storage. It reduced the growth but did not totally eliminate mycoplasmas and ureaplasmas from cooled-stored dog semen.

Systematic review: the burden of disruptive gastro-oesophageal reflux disease on health-related quality of life.

BACKGROUND: About one-third of patients with gastro-oesophageal reflux disease (GERD) have frequent and/or severe reflux symptoms ('disruptive GERD'). The relative burden of disruptive GERD on health-related quality of life (HRQL) has not been systematically investigated. AIM: To assess the burden of disruptive vs. nondisruptive GERD on HRQL. METHODS: Systematic searches were conducted in PubMed and Embase. To be included, studies had to have used validated questionnaires to assess HRQL. RESULTS: Nineteen studies were included. Data on the comparative burden of frequent (ranging from daily to ≥weekly) and severe reflux symptoms were provided in eight and 13 studies respectively; six reported on the additional burden of nocturnal symptoms. Compared with individuals with nondisruptive GERD, those with disruptive GERD had 2.4-times and 1.5-times higher mean rates of absenteeism and presenteeism respectively (five studies), 1.5-times lower sleep quality scores (three studies), 1.1-times lower mean summary scores for physical and mental health (five studies) and 1.3-times lower mean scores for psychological and general well-being (four studies). Increasing symptom frequency and severity both increased the burden of disease to a similar extent. The presence of nocturnal symptoms in addition to daytime symptoms led to worsening of physical health, but their effect on mental health and work productivity was less clear. CONCLUSIONS: Disruptive GERD is associated with a high burden of disease compared with occasional or mild reflux symptoms. Disease management needs to vary across the GERD spectrum and should be tailored to patients' requirements for optimal therapeutic outcomes.

Systematic review: the association between symptomatic response to proton pump inhibitors and health-related quality of life in patients with gastro-oesophageal reflux disease.

BACKGROUND: Some patients with gastro-oesophageal reflux disease (GERD) experience persistent reflux symptoms on proton pump inhibitor (PPI) therapy. The relationship between persistent reflux symptoms and health-related quality of life (HRQoL) is unclear. AIM: To assess the relationship between persistent reflux symptoms on PPI therapy and HRQoL in patients with GERD. METHODS: Systematic searches were conducted in PubMed and Embase. Eligible studies had to have used psychometrically evaluated patient reported outcome instruments to assess HRQoL. RESULTS: Nine studies were included; supplementary data were obtained for four of these. The effect of persistent reflux symptoms despite PPI therapy on physical HRQoL was assessed in seven studies and that on mental HRQoL in five studies. Compared with patients whose reflux symptoms responded to PPIs, those with persistent symptoms had, on average, 8-16% lower scores for physical health (five studies) and 2-12% lower scores for mental health (three studies). Three studies included data on the effect of baseline HRQoL on subsequent symptomatic response to PPI therapy. Patients with persistent symptoms had clinically relevant lower psychological well-being at baseline compared with those whose symptoms responded to PPIs (average score difference: 7%; two studies). High anxiety levels at baseline seemed to be an important aspect of persistent symptoms. CONCLUSIONS: Persistent reflux symptoms on PPI therapy are associated with reduced physical and mental HRQoL, while reduced mental HRQoL at baseline seems to impair symptomatic response to PPIs. HRQoL may need to be considered alongside reflux symptom frequency and severity when making decisions about disease management.

Systematic review: ageing and gastro-oesophageal reflux disease symptoms, oesophageal function and reflux oesophagitis.

BACKGROUND: Gastro-oesophageal reflux disease (GERD) is thought to become more prevalent with age. AIM: To assess systematically how age affects the prevalence of GERD and its oesophageal complications. METHODS: Systematic PubMed searches were used to identify population-based studies on the age-related prevalence and incidence of GERD, and clinical studies on age-related changes in oesophageal complications in GERD. RESULTS: Nine population-based studies and seven clinical studies met the inclusion criteria. Four of seven prevalence studies observed no significant effect of age on GERD symptom prevalence, two did not report on statistical significance and one observed a significant age-related increase in symptom prevalence. The two population-based endoscopic surveys showed no significant effect of age on reflux oesophagitis prevalence. Clinical studies in patients with GERD showed an increase in reflux oesophagitis severity and a decrease in heartburn severity with age, and age-related increases in oesophageal acid exposure and anatomical disruption of the gastro-oesophageal junction. CONCLUSIONS: Epidemiological studies do not show an increase in GERD symptom prevalence with age. However, in individuals with GERD, ageing is associated with more severe patterns of acid reflux and reflux oesophagitis; despite this, symptoms associated with GERD become less severe and more nonspecific with ageing. Thus, the real prevalence of GERD may well increase with age.

Systematic review: persistent reflux symptoms on proton pump inhibitor therapy in primary care and community studies.

BACKGROUND: Persistent gastro-oesophageal reflux disease (GERD) symptoms can occur despite proton pump inhibitor (PPI) therapy. AIM: To assess the prevalence and potential determinants of persistent GERD symptoms in primary care and community-based studies. METHODS: Studies were identified by systematic PubMed and Embase searches; pooled prevalence data are shown as sample-size weighted means and 95% confidence intervals. RESULTS: Nineteen studies in individuals with GERD taking a PPI were included. In interventional, nonrandomized primary care trials, the prevalence of persistent troublesome heartburn and regurgitation was 17% (6-28%) and 28% (26-30%) respectively; in randomized trials, it was 32% (25-39%) and 28% (26-30%), respectively. In observational primary care and community-based studies, 45% (30-60%) of participants reported persistent GERD symptoms. Overall, persistent GERD symptoms despite PPI treatment were more likely in studies with a higher proportion of female participants [>60% vs. <50%, risk ratio (RR): 3.66; P < 0.001], but less likely in studies from Europe than in those from the USA (RR: 0.71; P < 0.001), and were associated with decreased psychological and physical well-being. CONCLUSIONS: Persistent GERD symptoms despite PPI treatment are common in the primary care and community setting. Alternative approaches to management are required.

Selective anthelmintic therapy of horses in the Federal states of Bavaria (Germany) and Salzburg (Austria): an investigation into strongyle egg shedding consistency.

For 9 consecutive months (March-November 2008), faecal samples were collected monthly from 129 horses residing within 40 km of Salzburg, Austria. Samples were analysed quantitatively using a modified McMaster egg counting technique. Whenever a faecal egg count (FEC) result exceeded 250 eggs per gram (EPG), the horse was treated with pyrantel, ivermectin or moxidectin. In 52 of 129 horses (40.3%), no strongyle eggs were ever detected over the course of 9 months. In 39 horses (30.2%), strongyle eggs were detected in at least 1 sample, but the egg count never exceeded 250 EPG. The remaining 38 (29.5%) horses were treated at least once in response to a FEC that exceeded 250 EPG. As a result of this selective anthelmintic scheme, the total number of anthelmintic treatments was reduced to 54% of the number of treatments administered to the same horses in the previous year. Both the maximum and mean FEC dropped significantly after initiation of the study. A statistically significant, negative correlation was demonstrated between the maximum and mean FEC of a horse and its age. Pasture hygiene appeared to reduce FECs, but the effect was not statistically significant. The magnitude of the initial FEC was significantly correlated with the maximum FECs in the subsequent 8 months (p<0.01). The same relationship was observed for the maximum FEC of the first 2 samples. Furthermore, horses which required several anthelmintic treatments had a higher initial FEC and a greater maximum FEC in the first 2 samples than horses which received only one or no treatment. These results suggest that selective anthelmintic treatment accomplished a reduced pasture contamination with strongyle eggs, while simultaneously decreasing the number of anthelmintic treatments. Sustained implementation of a selective treatment strategy has the potential to reduce selection pressure for anthelmintic resistance. These results reported herein will assist equine practitioners in designing and monitoring sustainable anthelmintic treatment programs.

[Luteal insufficicency in the bitch - symptoms, diagnosis, consequences and therapy. A review of the literature]. / Luteale Insuffizienz bei der Hündin - Symptome, Diagnose, Folgen und Therapie. Eine Übersicht der Literatur.

Insufficient progesterone synthesis, so called hypoluteoidism or luteal insufficiency, is one of the possible reasons for infertility in the bitch. Confirming this diagnosis may be difficult if the dynamic changes of progesterone during the reproductive cycle are not taken into account. The bitch ovulates at progesterone concentrations of about 5-10ng/ml (15.7-31.4 nmol/L). The concentrations increase to >25ng/mL (78.5 nmol/L) within 3-4 weeks and then subsequently decrease after a plateau of 7-14 days. In the pregnant bitch, progesterone rapidly drops to <2ng/ml (6.3 nmol/L) approximately 24-48 hours before parturition induced by PGF2α secretion. Luteal insufficiency, characterized as an early decrease of progesterone secretion, is most commonly observed between days 20 and 35 of pregnancy. Progesterone concentrations of approximately 2ng/ml (6.3nmol/L) are thought to be necessary for maintaining pregnancy. Lower concentrations result in resorption and abortion, respectively. In bitches suspected to have luteal insufficiency, weekly progesterone determinations using quantitative tests should be performed from 5-7 days after mating or at least from the date of early pregnancy diagnosis. The frequency has to be increased in the case of progesterone concentrations below 10ng/ml (31.4 nmol/L). Progesterone administration is indicated in the case of viable foetuses and progesterone concentrations <5 ng/ml (15.7 nmol/L) before day 58/60 of pregnancy or after the detection of a rapid progesterone decline of about 10-15ng/ml (31.4-47.1 nmol/L) between days 20 and 35 with viable foetuses in the sonographic examination. Either natural or synthetic progestins can be used. However, synthetic progestins have a greater risk potential for side effects (masculinisation of female puppies and cryptorchidism in male puppies), especially when administered between days 20 and 35 of pregnancy. Administration of natural progesterone should be stopped 2-3 days before expected parturition otherwise it would result in a prolonged duration of pregnancy with dystocia and stillbirth.

[Prevalence of caries, fissure sealants and filling materials among German children and children of migrants]. / Prävalenz von Karies, Fissurenversiegelungen und Füllungsmaterial bei deutschen Kindern und Kindern von Migranten.

The aim of this study was to collect information on dental health and dental care of German children and children of migrants for planning oral health promotion in the Rems-Murr-district. To meet this aim all first and fourth degree children in primary and special schools were examined. The dmft- and DMFT-Index, the number of fissure sealants, the filling material used and the children's nationality were recorded. The dmft of 6- and 7-year-olds was 1.50 among Germans, 4.61 among German migrants from Russia, 4.02 among Turks, 4.05 among children from former Yugoslavia, 2.35 among Italians, 1.95 among Greeks and 3.76 among children of other nationalities. At the age of 9 to 10 years Germans had an average of 0.31, German migrants from Russia 0.77, Turks 1.19, children from former Yugoslavia 1.32, Italians 0.64, Greeks 0.69 and children of other nationalities 0.57 DMF-teeth. In both age groups the proportion of caries-free children was highest among Germans and lowest among Turks. Also, more migrants than Germans were referred to a dentist for caries treatment. Compared to the Germans fewer migrants had at least one tooth sealed. The proportion of amalgam fillings to the total number of fillings was higher among 9- and 10-year-olds of Turkish, Italian or Yugoslavian origin than among other nationalities. The results of this study show that further development of oral health promotion programmes for children and parents with Turkish and Russian cultural background has the top-most priority.

Isolation, characterization, and recombinant expression of multiple serpins from the cat flea, Ctenocephalides felis.

Several clones encoding serine protease inhibitors were isolated from larval and adult flea cDNA expression libraries by immunoscreening and PCR amplification. Each cDNA contained an open reading frame encoding a protein of approximately 45 kDa, which had significant sequence similarity with the serpin family of serine protease inhibitors. The thirteen cDNA clones isolated to date encode serpin proteins, which share a primary structure that includes a nearly identical constant region of about 360 amino acids, followed by a C-terminal variable region of about 40-60 amino acids. The variable C-terminal sequences encode most of the reactive site loop (RSL) and are generated by mutually exclusive alternative exon splicing, which may confer unique protease selectivity to each serpin. Utilization of an alternative exon splicing mechanism has been verified by sequence analysis of a flea serpin genomic clone and adjacent genomic sequences. RNA expression patterns of the cloned genes have been examined by Northern blot analysis using variable region-specific probes. Several putative serpins have been overexpressed using the cDNA clones in Escherichia coli and baculovirus expression systems. Two purified baculovirus-expressed recombinant proteins have N-terminal amino acid sequences identical to the respective purified native mature flea serpins indicating that appropriate N-terminal processing occurred in the virus-infected insect cells.

The gamma-aminobutyric acid receptor B, but not the metabotropic glutamate receptor type-1, associates with lipid rafts in the rat cerebellum.

Recent evidence suggests that specialized microdomains, called lipid rafts, exist within plasma membranes. These domains are enriched in cholesterol and sphingolipids and are resistant to non-ionic detergent-extraction at 4 degrees C. They contain specific populations of membrane proteins, and can change their size and composition in response to cellular signals, resulting in activation of signalling cascades. Here, we demonstrate that both the metabotropic gamma-aminobutyric acid receptor B (GABA(B) receptor) and the metabotropic glutamate receptor-1 from rat cerebellum are insoluble in the non-ionic detergent Triton X-100. However, only the GABA(B) receptor associates with raft fractions isolated from rat brain by sucrose gradient centrifugation. Moreover, increasing the stringency of isolation by decreasing the protein : detergent ratio caused an enrichment of the GABA(B) receptor in raft fractions. In contrast, depletion of cholesterol from cerebellar membranes by either saponin or methyl-beta-cyclodextrin treatment, which solubilize known raft markers, also increased the solubility of the GABA(B) receptor. These properties are all consistent with an association of the GABA(B) receptor with lipid raft microdomains.

Activity-dependent changes of the presynaptic synaptophysin-synaptobrevin complex in adult rat brain.

The vesicular protein synaptobrevin contributes to two mutually exclusive complexes in mature synapses. Synaptobrevin tightly interacts with the plasma membrane proteins syntaxin and SNAP 25 forming the SNARE complex as a prerequisite for exocytotic membrane fusion. Alternatively, synaptobrevin binds to the vesicular protein synaptophysin. It is unclear whether SNARE complex formation is diminished or facilitated when synaptobrevin is bound to synaptophysin. Here we show that the synaptophysin-synaptobrevin complex is increased in adult rat brain after repeated synaptic hyperactivity in the kindling model of epilepsy. Two days after the last kindling-induced stage V seizure the relative amount of synaptophysin-synaptobrevin complex obtained by co-immunoprecipitation from cortical and hippocampal membranes was increased twofold compared to controls. By contrast the relative amounts of various synaptic proteins as well as that of the SNARE complex did not change in membrane preparations from kindled rats compared to controls. The increased amount of synaptophysin-synaptobrevin complex in kindled rats supports the idea that this complex represents a reserve pool for synaptobrevin enabling synaptic vesicles to adjust to an increased demand for synaptic efficiency. We conclude that the synaptophysin-synaptobrevin interaction is involved in activity-dependent plastic changes in adult rat brain.

Cross-resistance between triclosan and antibiotics in Pseudomonas aeruginosa is mediated by multidrug efflux pumps: exposure of a susceptible mutant strain to triclosan selects nfxB mutants overexpressing MexCD-OprJ.

Triclosan is an antiseptic frequently added to items as diverse as soaps, lotions, toothpaste, and many commonly used household fabrics and plastics. Although wild-type Pseudomonas aeruginosa expresses the triclosan target enoyl-acyl carrier protein reductase, it is triclosan resistant due to expression of the MexAB-OprM efflux system. Exposure of a susceptible Delta(mexAB-oprM) strain to triclosan selected multidrug-resistant bacteria at high frequencies. These bacteria hyperexpressed the MexCD-OprJ efflux system due to mutations in its regulatory gene, nfxB. The MICs of several drugs for these mutants were increased up to 500-fold, including the MIC of ciprofloxacin, which was increased 94-fold. Whereas the MexEF-OprN efflux system also participated in triclosan efflux, this antimicrobial was not a substrate for MexXY-OprM.

Synaptobrevin 2 is palmitoylated in synaptic vesicles prepared from adult, but not from embryonic brain.

Neuronal SNARE-proteins such as synaptobrevin, SNAP 25, and synaptotagmin are key players during neurosecretion. So far palmitoylation of SNAP-25 and synaptotagmin 1 have been described in vivo. Here we have analyzed palmitoylation of the SNARE-proteins synaptobrevin 2 and synaptotagmin in vitro using synaptosomal and synaptic vesicle preparations from rat brain. Labeling of synaptic vesicles prepared from adult brain with [3H]palmitate revealed synaptobrevin 2 besides synaptotagmin 1 as major palmitoylated proteins. [3H]Palmitoylation of synaptobrevin 2 was resistant to chloroform/methanol extraction, but sensitive to reducing agents indicating a covalent fatty acid bond to cysteine residues. Palmitoylation of synaptobrevin 2 was also confirmed using endogenous synaptobrevin 2 present in PC-12 cells and synaptobrevin 2 expressed with a vacciniavirus system in Cos cells. In contrast to the situation seen with membrane preparations obtained from adult brain, synaptic vesicles prepared from embryonic rat brain did not support [3H]palmitoylation of synaptobrevin and synaptotagmin. These results suggest, that both synaptobrevin 2 and synaptotagmin were efficiently palmitoylated from mature synaptic vesicles. However, at least one component of the palmitoylation machinery is developmentally upregulated.