Surveillance of biting midges (Culicoides spp.) in Northern Ireland: influence of seasonality, surrounding habitat and livestock housing.

Biting midges, Culicoides spp. (Diptera: Ceratopogonidae), are important vectors of viral pathogens. Following the outbreak of bluetongue serotype 8 in Europe between 2006 and 2009, many Culicoides surveillance programmes were initiated to identify vector-active periods, in accordance with European Commission regulation 2007/1266/EC. This study utilized surveillance data from 4 years of continuous light-trapping at 14 sites in Northern Ireland. The number of captured Culicoides varied from none during the vector-free period (December-April) to more than 36 000 per night during peak activity in the summer. The Obsoletus group represented 75% of Culicoides collected and the Pulicaris group represented 21%. A total of 91% of Culicoides were female, of which 42% were parous. Abundance data, sex ratios and parous rates suggested that both the Obsoletus and Pulicaris groups underwent three generations/year. The Obsoletus group was associated with cattle-rearing habitats and woodland, the Impunctatus group was found in habitats related to sheep rearing and the Pulicaris group were associated with both cattle and sheep. Housing did not reduce incursion of female Obsoletus group Culicoides but it did for males and for the Pulicaris group Culicoides. The influence of housing was strongly affected by time of year, probably reflecting the presence of livestock indoors/outdoors.

Sticky-trapping biting midges (Culicoides spp.) alighting on cattle and sheep: effects of trap colour and evidence for host preference.

Sticky traps were mounted on heifers and sheep to assess Culicoides spp. (Diptera: Ceratopogonidae) host preference. Initially, four coloured 200-cm(2) sticky traps (white, clear, yellow and blue) were attached to the backs of each of ten Friesian heifers that were released into open pasture for 24 h, repeated on six occasions. More Obsoletus group Culicoides were caught on the white and clear traps than on the yellow and blue. Trap position on the right or left flank also affected midge catch, probably due to heifer orientation in the field. Next, six Friesian heifers and six Charollais hoggets each had one clear and one white sticky strap attached to their backs for one 24-h period per week, repeated for 24 weeks. Overall, Obsoletus group Culicoides comprised 91.8% (n = 5, 955) of the midge catch but there was no evidence of host preference, either discounting or including host live weight in the analyses. However, Pulicaris group Culicoides did demonstrate a significant host preference for sheep, providing that the analysis was adjusted for live weight. On heifers, the Pulicaris group comprised 7.5% of biting midges caught, whereas on hoggets, it comprised 12.7%.

Use of a synthetic lethal screen to identify genes related to TIF51A in Saccharomyces cerevisiae.

The putative eukaryotic translation initiation factor 5A (eIF5A) is an essential protein for cell viability and the only cellular protein known to contain the unusual amino acid residue hypusine. eIF5A has been implicated in translation initiation, cell proliferation, nucleocytoplasmic transport, mRNA decay, and actin polarization, but the precise biological function of this protein is not clear. However, eIF5A was recently shown to be directly involved with the translational machinery. A screen for synthetic lethal mutations was carried out with one of the temperature-sensitive alleles of TIF51A (tif51A-3) to identify factors that functionally interact with eIF5A and revealed the essential gene YPT1. This gene encodes a small GTPase, a member of the rab family involved with secretion, acting in the vesicular trafficking between endoplasmatic reticulum and the Golgi. Thus, the synthetic lethality between TIF51A and YPT1 may reveal the connection between translation and the polarized distribution of membrane components, suggesting that these proteins work together in the cell to guarantee proper protein synthesis and secretion necessary for correct bud formation during G1/S transition. Future studies will investigate the functional interaction between eIF5A and Ypt1 in order to clarify this involvement of eIF5A with vesicular trafficking.

Use of a synthetic lethal screen to identify genes related to TIF51A in Saccharomyces cerevisiae

The putative eukaryotic translation initiation factor 5A (eIF5A) is an essential protein for cell viability and the only cellular protein known to contain the unusual amino acid residue hypusine. eIF5A has been implicated in translation initiation, cell proliferation, nucleocytoplasmic transport, mRNA decay, and actin polarization, but the precise biological function of this protein is not clear. However, eIF5A was recently shown to be directly involved with the translational machinery. A screen for synthetic lethal mutations was carried out with one of the temperature-sensitive alleles of TIF51A (tif51A-3) to identify factors that functionally interact with eIF5A and revealed the essential gene YPT1. This gene encodes a small GTPase, a member of the rab family involved with secretion, acting in the vesicular trafficking between endoplasmatic reticulum and the Golgi. Thus, the synthetic lethality between TIF51A and YPT1 may reveal the connection between translation and the polarized distribution of membrane components, suggesting that these proteins work together in the cell to guarantee proper protein synthesis and secretion necessary for correct bud formation during G1/S transition. Future studies will investigate the functional interaction between eIF5A and Ypt1 in order to clarify this involvement of eIF5A with vesicular trafficking.

The relationship between nuclear colour and opalescence on the LOCSIII scale and physical characteristics of cataract nuclei.

PURPOSE: To evaluate the compression characteristics of the human lens nucleocortex in relation to its LOCSIII clinical grading. METHODS: Sixteen subjects undergoing planned extracapsular cataract surgery had pre-operative slit-lamp examination and assessment of cataract LOCSIII grade followed by postoperative in vitro evaluation of the nucleus with measurement of 'linear compressibility' by a purpose-designed caliper incorporating a strain gauge, enabling the derivation of a graph of nuclear compression (D (mm) against applied force (F (N)). RESULTS: Nuclear colour correlates with the force required to compress a lens to 75% of its original depth (F75) (R = 0.625, P = 0.017). Nuclear opalescence correlates with the force required to compress a lens to 75% of its original depth (R = 0.651, P = 0.012) and inversely with linear compressibility (DeltaD/DeltaF, the slope of the graph of nuclear compression against applied force) (R = -0.610, P = 0.014). F75 is a direct and linear compressibility is an inverse related parameter of lens nucleus 'hardness'. CONCLUSION: A new instrument is described which allows measurement of 'hardness'-related compression characteristics of the human cataract in vitro. There is a relationship between the LOCSIII clinical classification of nuclear cataracts and mechanical compression characteristics of the cataractous lens. LOCSIII classification may aid the preoperative planning of an appropriate surgical approach to an individual cataract.

An outbreak of methicillin resistant Staphylococcus aureus on a burn unit: potential role of contaminated hydrotherapy equipment.

OBJECTIVE: To report a multi-institution outbreak caused by a single strain of methicillin-resistant Staphylococcus aureus (MRSA). OUTBREAK: Between September 19 and November 20, 1996 an index case and five secondary cases of nosocomial MRSA occurred on a 26 bed adult plastic surgery/burn unit (PSBU) at a tertiary care teaching hospital. Between November 11 and December 23, 1996, six additional cases were identified at a community hospital. One of the community hospital cases was transferred from the PSBU. All strains were identical by pulsed-field gel electrophoresis. MRSA may have contributed to skin graft breakdown in one case, and delayed wound healing in others. Patients required 2 to 226 isolation days. CONTROL MEASURES: A hand held shower and stretcher for showering in the hydrotherapy room of the PSBU were culture positive for the outbreak strain, and the presumed means of transmission. Replacement of stretcher showering with bedside sterile burn wound compresses terminated the outbreak. The PSBU was closed to new admissions and transfers out for 11 days during the investigation. Seven of 12 patients had effective decolonization therapy. CONCLUSION: Environmental contamination is a potential source of nosocomial MRSA transmission on a burn unit. Notification among institutions and community care providers of shared patients infected or colonized with an antimicrobial resistant microorganism is necessary.

Developmental onset of eating-related color-naming interference: the role of restraint and eating psychopathology.

OBJECTIVE: This study investigated the developmental onset of the Stroop interference effect for food and body shape words in 12- and 14-year-old females to determine whether dietary restraint and eating psychopathology influenced Stroop performance times. METHOD: A Stroop task containing neutral, food, and body shape-related words was administered to 152 schoolgirls. Participants completed the restraint scale of the Dutch Eating Behavior Questionnaire and the Drive for Thinness (DFT) subscale of the Eating Disorders Inventory. RESULTS: Significant color-naming impairments were observed for food-related words in 12- and 14-year-olds, in 14-year-old restrained eaters, and in 12-year-old unrestrained eaters. There were no significant differences between restrained and unrestrained eaters in either age group. Participants scoring high on the DFT subscale showed significant impairments for food-related words, but did not differ significantly from those scoring low on the DFT. There were no significant impairments in color-naming body shape-related words in any subgroups. DISCUSSION: This study did not confirm a different developmental onset for the food and body shape Stroop interference effect. Consideration of dietary restraint did add clarity to previously observed food-related interference effects in both age groups. The results for high- and low-DFT participants do not support the use of the eating-related Stroop tests as an early objective indicator of eating psychopathology.

Conserved sequences in the beta subunit of archaeal and eukaryal translation initiation factor 2 (eIF2), absent from eIF5, mediate interaction with eIF2gamma.

The eukaryotic translation initiation factor 2 (eIF2) binds the methionyl-initiator tRNA in a GTP-dependent mode. This complex associates with the 40 S ribosomal particle, which then, with the aid of other factors, binds to the 5' end of the mRNA and migrates to the first AUG codon, where eIF5 promotes GTP hydrolysis, followed by the formation of the 80 S ribosome. Here we provide a comparative sequence analysis of the beta subunit of eIF2 and its archaeal counterpart (aIF2beta). aIF2beta differs from eIF2beta in not possessing an N-terminal extension implicated in binding RNA, eIF5 and eIF2B. The remaining sequences are highly conserved, and are shared with eIF5. Previously isolated mutations in the yeast eIF2beta, which allow initiation of translation at UUG codons due to the uncovering of an intrinsic GTPase activity in eIF2, involve residues that are conserved in aIF2beta, but not in eIF5. We show that the sequence of eIF2beta homologous to aIF2beta is sufficient for binding eIF2gamma, the only subunit with which it interacts, and comprises, at the most, 78 residues. eIF5 does not interact with eIF2gamma, despite its similarity with eIF2beta, probably because of a gap in homology in this region. These observations have implications for the evolution of the mechanism of translation initiation.

The beta subunit of eukaryotic translation initiation factor 2 binds mRNA through the lysine repeats and a region comprising the C2-C2 motif.

Eukaryotic translation initiation factor 2 (eIF2) has been implicated in the selection of the AUG codon as the start site for eukaryotic translation initiation, since mutations in its three subunits in yeast that allow the recognition of a UUG codon by the anticodon of the initiator Met-tRNAMet have been identified. All such mutations in the beta subunit of eIF2 (eIF2beta) mapped to a region containing a putative zinc finger structure of the C2-C2 type, indicating that these sequences could be involved in RNA recognition. Another feature of eIF2beta that could mediate an interaction with RNA is located in the amino-terminal sequences and is composed of three repeats of seven lysine residues which are highly conserved in other species. We show here the ability of eIF2beta, purified from Escherichia coli as a fusion to glutathione S-transferase, to bind mRNA in vitro. Through a deletion analysis, mRNA binding was found to be dependent on the lysine repeats and a region encompassing the C2-C2 motif. Strong mRNA binding in vitro could be maintained by the presence of only one lysine or one arginine run but not one alanine run. We further show that only one run of lysine residues is sufficient for the in vivo function of eIF2beta, probably through charge interaction, since its replacement by arginines did not impair cell viability, whereas substitution for alanines resulted in inviable cells. mRNA binding, but not GTP-dependent initiator Met-tRNAMet binding, by the eIF2 complex was determined to be dependent on the presence of the lysine runs of the beta subunit.

Effect of exposure to balanced salt solution upon the hardness of the crystalline lens.

BACKGROUND: The nucleus confers most of the hardness upon the lens, water content decreases towards the centre of the nucleus and a relative dehydration accompanies increased hardness in some cataractous lenses. It is a possibility that exposure and incubation of the inner layers of the nucleus to balanced salt solution (BSS) can result in the softening of the nucleus. PURPOSE: This study aimed to investigate the effect of BSS upon the lens hardness. METHODS: Nuclear colour element of cataract was graded biomicroscopically. Following extracapsular cataract surgery the lens nucleocortex was divided into two equal parts and each half was allocated randomly to incubation in BSS or air for 5 min before the hardness of each section was assessed by an automated guillotine. RESULTS: Following incubation with BSS the mean force necessary to bisect the lens was 0.50 N and in the control air group the mean force was 0.64 N. The lenses in the BSS-treated group were consistently softer than those in the control group, with a mean softening of 18.3% (P=0.001). The amount of softening was not related to the nuclear colour (P=0.6) or age (P=0.1). CONCLUSION: Softening of the lens through physical disruption has previously been reported. This study describes the phenomenon of nuclear softening following exposure to BSS, indicating that lens softening can occur through biochemical means.

Peroxisome proliferator-activated receptors gamma and alpha mediate in vivo regulation of uncoupling protein (UCP-1, UCP-2, UCP-3) gene expression.

A role for peroxisome proliferator-activated receptors, PPAR gamma and PPAR alpha, as regulators of energy homeostasis and lipid metabolism, has been suggested. Recently, three distinct uncoupling protein isoforms, UCP-1, UCP-2, and UCP-3, have also been identified and implicated as mediators of thermogenesis. Here, we examined whether in vivo PPAR gamma or PPAR alpha activation regulates the expression of all three UCP isoforms. Rats or lean and db/db mice were treated with PPAR gamma [thiazolidinedione (TZD)] or PPAR alpha (WY-14643) agonists, followed by measurement of messenger RNAs (mRNAs) for UCP-1, UCP-2, and UCP-3 in selected tissues where they are expressed. TZD treatment (AD 5075 at 5 mg/kg x day) of rats (14 days) increased brown adipose tissue (BAT) depot size and induced the expression of each UCP mRNA (3x control levels for UCP-1 and UCP-2, 2.5x control for UCP-3). In contrast, UCP-2 and UCP-3 mRNA levels were not affected in white adipose tissue or skeletal muscle. Chronic (30 days) low-dose (0.3 mg/kg x day) TZD treatment induced UCP-1 mRNA and protein in BAT (2.5x control). In contrast, chronic TZD treatment (30 mg/kg x day) suppressed UCP-1 mRNA (>80%) and protein (50%) expression in BAT. This was associated with further induction of UCP-2 expression (>10-fold) and an increase in the size of lipid vacuoles, a decrease in the number of lipid vacuoles in each adipocyte, and an increase in the size of the adipocytes. TZD treatment of db/db mice (BRL 49653 at 10 mg/kg x day for 10 days) also induced UCP-1 and UCP-3 (but not UCP-2) expression in BAT. PPAR alpha is present in BAT, as well as liver. Treatment of rats or db/db mice with WY-14643 did not affect expression of UCP-1, -2, or -3 in BAT. Hepatic UCP-2 mRNA was increased (4x control level) in db/db and lean mice, although this effect was not observed in rats. Thus, in vivo PPAR gamma activation can induce expression of UCP-1, -2, and -3 in BAT; whereas chronic-intense PPAR gamma activation may cause BAT to assume white adipose tissue-like phenotype with increased UCP-2 levels. PPAR alpha activation in mice is sufficient to induce liver UCP-2 expression.

Does postsynaptic alpha 1-adrenergic receptor supersensitivity contribute to autonomic dysreflexia?

Quadriplegics often experience periods of severe hypertension known as autonomic dysreflexia. Clinically, these events have been well documented, but the mechanisms for mediating autonomic dysreflexia remain unclear. We used a chronic rat model to investigate the potential development of supersensitivity at postsynaptic alpha 1-adrenergic receptors as a contributing factor to the exaggerated sympathetic response characteristic of autonomic dysreflexia. Adult male Wistar and Sprague-Dawley rats were anesthetized and given spinal transection at T5. After 30 days, rats were reanesthetized and arterial and venous catheters implanted. Twenty-four hours later, colorectal distension (CRD) was used to evoke autonomic dysreflexia in conscious, spinalized rats. To gauge changes in alpha 1-receptor sensitivity, we assessed mean arterial pressure (MAP) in response to intravenous phenylephrine (PE) infusions. No consistent differences were observed between intact and spinalized rats. Therefore, supersensitivity of alpha 1-receptors cannot completely account for the hypertensive bouts associated with autonomic dysreflexia. In addition, while attempting to develop an appropriate model for autonomic dysreflexia, we discovered that spinalized Wistar rats exhibited MAP responses characteristic of autonomic dysreflexia, whereas lesioned Sprague-Dawley rats did not, when subjected to CRD. Thus Wistar rats provide a better animal model for autonomic dysreflexia.

Desensitization of beta3-adrenergic receptor-stimulated adenylyl cyclase activity and lipolysis in rats.

The beta3-adrenergic receptor is an integral membrane protein consisting of seven transmembrane domains. Unlike the beta1 and beta2 receptors, this subtype lacks the consensus phosphorylation sites required for desensitization by serine kinases. Using the rodent specific beta3 agonist BRL 35135, our initial data indicated that beta3 receptor-mediated glycerol levels progressively decreased following daily oral doses of 5 mg/kg. Therefore, we initiated studies designed to delineate the possible mechanism(s) for this decreased response. Within 3 hours following a single oral dose of BRL 35135, serum glycerol levels and UCP (uncoupling protein) RNA levels were significantly increased whereas beta3 RNA levels were significantly decreased. Rats were dosed daily for 5 days with either vehicle or BRL 35135 (5 mg/kg, p.o.) and blood samples were collected for glycerol analysis. Adipose tissue was excised for lipolysis and adenyl cyclase measurements. In addition, UCP and beta3 receptor RNA levels were assessed. No effect on adipocyte BRL 37344-stimulated adenylyl cyclase activity was observed 3 hours following the initial dose of BRL 35135. Although a slight decrease (approximately 25%) in adenylyl cyclase activity could be observed 24 hours following the initial dose, it wasn't until day 4 of dosing that a significant decrease (50%) was observed. In contrast, beta3- stimulated lipolysis in adipocytes from BRL 35135-treated rats was decreased 85% within 24 hours and this decrease persisted through four days of treatment. These data indicate that the lipolytic response to beta3 receptor activation is decreased after only a single oral dose of BRL 35135, whereas receptor-mediated adenylyl cyclase activation, although initially unaffected, also desensitizes by day four of treatment.

Convergence of multiple sensory inputs onto neurons in the dorsolateral medulla in cats.

The dorsolateral medulla, including the nucleus reticularis parvicellularis, the cuneate nucleus, and the external cuneate nucleus, is an integrative region for a variety of sensory inputs. The purpose of this study was to determine whether individual neurons respond to a variety of different sensory modalities. To this end, responses of 40 neurons in the dorsolateral medulla to multiple sources of sensory input were assessed in cats anesthetized with alpha-chloralose. Neurons were located in the nucleus reticularis parvicellularis (24 cells, 60%), the cuneate nucleus (10 cells, 25%), and the external cuneate nucleus (6 cells, 15%). All neurons were tested for responses to: electrical stimulation of afferents coursing through the left stellate ganglion and afferents in the left cervical vagus nerve, and somatic, auditory, and visual stimulation. No neurons responded to all five stimuli. Three cells (7.5%) responded to four stimuli, 11 (27.5%) responded to three stimuli, 10 (25.0%) responded to two stimuli, and 15 (37.5%) responded to only a single stimulus. The remaining cell was unresponsive to any stimulus. As a group, neurons in the nucleus reticularis parvicellularis received input from the greatest number of sensory modalities, and cuneate nucleus neurons received input predominantly from somatosensory afferents. External cuneate nucleus neurons displayed response profiles intermediate between nucleus reticularis parvicellularis and cuneate nucleus. In addition, eight neurons (20% of the total) were sensitive to changes in blood pressure. Results of the present study support the hypothesis that neurons in the nucleus reticularis parvicellularis receive convergent inputs from different sensory modalities.2+ behaviors.

Phenylephrine and pilocarpine in the treatment of post-operative irido-corneal adhesion.

Following cataract surgery, entrapment of the iris within the surgical wound is often managed by intensive use of miotics. As the radial fibres stretch, only a small amount of fraction is exerted upon the entrapped iris. Application of a combination of phenylephrine and pilocarpine drops causes simultaneous contraction of the pupil sphincter and the radial muscle fibres. This study investigated the relative magnitude of forces induced in the iris periphery by pilocarpine and phenylephrine and the effectiveness of adding g. phenylephrine 10% to g. pilocarpine 4% drops in the treatment of postoperative irido-corneal adhesions. The investigation was divided into two parts. First, the forces induced in the iris periphery upon exposure to pilocarpine and phenylephrine were measured in 6 cadaver irises. The mean force was 27.5 +/- 5.7 x 10(-3) N for pilocarpine and 23.3 +/- 4.0 x 10(-3) N for phenylephrine. The combination of the two drugs produced a force of 54.2 +/- 6.6 x 10(-3) N (p < 0.05). In the second part of the study intensive pilocarpine 4% drops were administered to 17 patients who had iris-wound entrapment on the first post-operative day. Patients with persistent adhesion were commenced on intensive g. phenylephrine 10% and assessed after 90 minutes. Of the 17 patients, 6 responded to pilocarpine drops alone; in a further 7 the irido-corneal adhesion was released only by the addition of phenylephrine drops, and in 4 patients drops were ineffective in relieving the adhesion. This study indicates that addition of phenylephrine 10% to pilocarpine 4% drops enhances the effectiveness of pharmacological treatment of post-operative irido-corneal adhesion.

Sickle retinopathy in patients with sickle trait.

Sickle trait is traditionally considered a benign condition by ophthalmologists. Three cases of sickle retinopathy in subjects with sickle trait are reported. In all cases the onset of retinopathy was related to other contributing factors: in one case a traumatic hyphaema and raised intraocular pressure, in two others diabetes mellitus. Patients with sickle trait are at risk of retinopathy if coincident ocular or systemic disease is present.

Auditing ophthalmology audits.

Medical audit is now a well-established part of the routine of ophthalmology departments. Accomplishing a complete audit is a complex task and its effectiveness depends on how it is performed. In order to evaluate the procedure in our department a retrospective analysis of 18 audits was carried out with particular reference to the level, objectives, beneficial effects, and effects on current practice. Our practice was critically analysed using these factors. One audit fulfilled the criteria for a full audit. Eleven (60%) were partial or potential and six (30%) were an attempt in planning an audit. The majority omitted plans for implementing change or targets for future assessment. Seven had educational benefit. There was little effect on patient care, cost-effectiveness or communication. Medical audit can be clinically effective, educational and stimulating. Failure to complete all stages affects the outcome. This study identifies the difficulties involved in performing complete audits and suggests improving the procedure by auditing audits on a regular basis.

Ophthalmologic features of thallium poisoning.

Thallium intoxication is characterized by the development of painful peripheral neuropathy, alopecia, mental disorders, and in severe cases, respiratory failure and death. Toxic optic neuropathy is also a feature. Ophthalmologic features of thallium poisoning include optic neuropathy, blepharoptosis, lens opacities, and ophthalmoplegia. A 44-year-old man with criminal sublethal thallium poisoning was examined one month after he was seen in the neurology department with classic systemic features. He was found to have diminished contrast sensitivity, a tritan defect in color vision, and a relative cecocentral scotoma before he developed optic atrophy.