Splicing features in maize streak virus virion- and complementary-sense gene expression.

The single-stranded DNA geminiviruses produce transcripts from both strands (virion- and complementary-sense) of a nuclear double-stranded DNA molecule. In maize streak virus (MSV)-infected maize plants, approximately 80% of the complementary-sense transcripts produce the C1 protein, whilst the remaining 20% are spliced to remove a 92 nt intron and produce a C1:C2 fusion protein (Rep). Disruption of the complementary-sense 3' splice site abolished virus replication.

Prostaglandin F2alpha-induced nest-building in pseudopregnant pigs. II. Space restriction stress does not influence secretion of oxytocin, prolactin, oestradiol or progesterone.

We have previously shown that prostaglandin F2alpha (PG) is capable of inducing nest-building behaviour in pseudopregnant gilts and established a protocol. This experiment examined which reproductive endocrine systems might mediate these behavioural responses, in the presence or absence of a space restriction stress. Pseudopregnancy was induced with 5 mg/day i.

Prostaglandin F2alpha-induced nest-building in pseudopregnant pigs. I. Effects of environment on behaviour and cortisol secretion.

Pigs may be susceptible to stress when they are strongly motivated to nest-build in a space-restricted environment. This study aimed to explore whether nest-building behaviour could be induced by prostaglandin F2alpha (PG) administration to pseudopregnant gilts and to determine whether induced behaviour and cortisol output differed between animals chronically placed in either farrowing crates or pens. Jugular vein catheters were placed on Day 39 of pseudopregnancy and blood samples collected daily from Day 40 to Day 48.

Cell attachment to, and contraction of, the retina in vitro.

Purpose: To examine the behavior of fibroblasts and retinal pigment epithelial cells after attachment to the retinal surface in vitro to elucidate the pathobiology of the early stages of epiretinal membrane formation.

Methods: Human retinal pigment epithelial (HRPE) cells and bovine Tenon's capsule fibroblasts (BTFs) were seeded onto the surface of bovine retinal explants maintained in organ culture. The changes induced in the underlying retina, including contraction, were assessed during a period of up to 10 days.

Teachers' views on bullying: definitions, attitudes and ability to cope.

Background: Teachers play a crucial role in preventing and managing the widespread problem of bullying. Despite this, scant attention has been paid to their views on this type of problem.

Aims: To determine (i) what behaviours teachers regard as bullying; (ii) teachers' attitudes towards bullying, bullies and victims; (iii) teachers' self-beliefs about their ability to deal with bullying and their need for training; (iv) teachers' views of their responsibility for bullying in various locations; (v) the impact of length of service on attitudes and perceived ability to cope with bullying.

Maize streak virus coat protein binds single- and double-stranded DNA in vitro.

Maize streak virus (MSV) coat protein (CP) is required for virus movement within the plant. Deletion or mutation of MSV CP does not prevent virus replication in single cells or protoplasts but leads to a loss of infectivity in the inoculated plant. The mechanism by which MSV CP mediates the transfer of MSV DNA from cell to cell and through the vascular bundle is still unknown.

Lymphatic drainage of the CNS: effects of lymphatic diversion/ligation on CSF protein transport to plasma.

The plasma recovery of an intraventricularly administered protein was compared before and after lymph diversion/ligation in the same conscious sheep to determine the relative roles of arachnoid villi and lymphatics in the clearance of a cerebral spinal fluid tracer. 125I-human serum albumin was injected into both lateral ventricles, and venous blood was sampled. One day later, multiple cervical vessels and the thoracic duct were cannulated for lymph collection.

Restricting maternal space during parturition in the pig. Effects on oxytocin, vasopressin and cortisol secretion following vagino-cervical stimulation and administration of naloxone.

This experiment studied the effects on endocrine and birth parameters of parturient pigs produced by restricting maternal freedom of movement without otherwise altering environment. Six primiparous pigs (gilts) were each given a jugular catheter under anaesthesia 7 days before parturition and commenced birth in a strawed pen, 2.0 m x 1.

Intravitreal growth factors in proliferative diabetic retinopathy: correlation with neovascular activity and glycaemic management.

Aim: Many growth factors are implicated in proliferative diabetic retinopathy (PDR). It was decided to test the hypothesis that no one factor is predominant but that a regular profile of levels of different growth factors might be operating, and that the profile might differ according to whether or not insulin therapy was part of the patient's glycaemic management. The levels of several growth factors in vitrectomy samples were therefore determined from diabetic patients with tractional, non-haemorrhagic sequelae of PDR and these levels were correlated with (a) each other (growth factor profile), (b) neovascular activity, and (c) the method of glycaemic management (insulin treated (IT) or non-insulin treated (NIT)).

Discrete regions of the sensor protein virA determine the strain-specific ability of Agrobacterium to agroinfect maize.

The ability of Agrobacterium strains to infect transformation-recalcitrant maize plants has been shown to be determined mainly by the virA locus, implicating vir gene induction as the major factor influencing maize infection. In this report, we further explore the roles of vir induction-associated bacterial factors in maize infection using the technique of agroinfection. The Ti plasmid and virA source are shown to be important in determining the ability of a strain to infect maize, and the monosaccharide binding protein ChvE is absolutely required for maize agroinfection.

Immunocytochemical study of retinal diode laser photocoagulation in the rat.

Aim: To determine the nature of the cellular infiltrate, alterations in cell adhesion molecules, and MHC II antigen expression in the rat retina following diode laser retinal photocoagulation.

Method: 20 normal Lister rats underwent diode laser photocoagulation of the retina. Frozen sections from eyes enucleated at 0, 1, 5, 13, and 33 days post laser were examined for T cells (R7.

Diurnal variations in human corneal thickness.

Aim: To elucidate the diurnal variation in human corneal thickness over a 48 hour period.

Method: Changes in central corneal thickness were monitored in eight healthy subjects (four male, four female) aged between 10 and 63 years using an ultrasonic pachymeter. Measurements were made over a 48 hour period-immediately before sleep, immediately upon waking and at 15, 30, 45 minutes, 1, 1.

Changes in content of mRNA encoding oxytocin in the pig uterus during the oestrous cycle, pregnancy, at parturition and in lactational anoestrus.

The aim of this study was to show that the pig uterus synthesizes oxytocin. Uteri were obtained from 2-7 pigs at regular intervals during the oestrous cycle, throughout pregnancy, at parturition and in lactational anoestrus. Localization of mRNA encoding oxytocin was by in situ hybridization and oxytocin concentrations were measured by radioimmunoassay.

Lymph and interstitial fluid dynamics in labial gingival tissues of sheep.

Lymphatic drainage and circulation in periodontal tissues have been cited as important components of host defence and pathogenic mechanisms, but quantitative data are sparse because of the technical difficulties associated with small animal lymphatic studies. However, the lymphatic vessels draining the periodontal tissues and surrounding region are sufficiently large in sheep to permit surgical placement of lymphatic catheters. Consequently, lymph and recirculating lymphocytes can be continuously collected and this permits the quantitative assessment of local immune responses in these tissues.

The effect of scatter laser photocoagulation on intravitreal levels of growth factors in the miniature pig.

Purpose: To characterise changes in intravitreal growth factor profiles following retinal photocoagulation in the miniature pig.

Methods: Miniature pig eyes underwent scatter photocoagulation by either diode infrared or emerald green laser. Animals were sacrificed at various times (up to 42 days) post-laser.

Qualitative research in health care: II. A structured review and evaluation of studies.

A hand search of the original papers in seven medical journals over 5 years was conducted in order to identify those reporting qualitative research. A total of 210 papers were initially identified, of which 70 used qualitative methods of both data collection and analysis. These papers were evaluated by the researchers using a checklist which specified the criteria of good practice.

Drainage of CSF through lymphatic pathways and arachnoid villi in sheep: measurement of 125I-albumin clearance.

We investigated lymphatic drainage pathways of the central nervous system in conscious sheep and quantified the clearance of a cerebrospinal fluid (CSF) tracer into lymph and blood. In the first group of studies, 125I-HSA was injected into the lateral ventricles of the brain or into lumbar CSF and after 6 h, various lymph nodes and tissues were excised and counted for radioactivity. Multiple lymphatic drainage pathways of cranial CSF existed in the head and neck region defined by elevated 125I-HSA in the retropharyngeal/cervical, thymic, pre-auricular and submandibular nodes.

Qualitative research in health care: I. The scope and validity of methods.

It is increasingly argued that qualitative approaches have an important role in health care research. A wide range of methods are used to collect qualitative data, including in-depth interviews, focus groups and observational methods such as participant observation. The reliability and validity of qualitative studies can be addressed by a variety of techniques.

The views of general practitioners on community carrier screening for cystic fibrosis.

Background: Recent developments in molecular genetics have made it possible to identify carriers of the cystic fibrosis (CF) mutation, regardless of family history, before they have an affected child. Using these techniques, population or 'community' carrier screening can offer informed reproductive choice to individuals and couples who would not otherwise know of their risk of having a CF child.

Aim: This study set out to assess the views of general practitioners (GPs) on community carrier screening for CF and to consider the factors that influence their willingness to offer it themselves.

A simple organ culture model for assessing the effects of growth factors on corneal re-epithelialization.

The effects of growth factors on re-epithelialization of wounded human and bovine corneas were studied in a simple organ culture system. Excisional trephine and epithelial scrape wounds were created on bovine and human corneo-scleral rings in which the endothelial corneal concavity was then filled with an agar-collagen mixture. Organ culture was undertaken at 37 degrees C in a humidified 5% CO2 incubator with serum-free Medium 199 maintained at the level of the conjunctival epithelium.

Three dimensional analysis of the retinal vasculature using immunofluorescent staining and confocal laser scanning microscopy.

Aim: To undertake a qualitative and quantitative analysis in three dimensions of the human retinal vasculature.

Method: Fixed and excised whole retinas were permeabilised and subjected to immunofluorescent staining for blood vessel components followed by confocal laser scanning microscopy. Single projection and stereoimages were constructed using computer software.

Oxygen modulates the response of the retinal pigment epithelium to basic fibroblast growth factor and epidermal growth factor by receptor regulation.

Purpose: To determine if low oxygen affects growth factor responsiveness in retinal pigment epithelial (RPE) cells and if such effects are mediated through changes in cell surface receptors.

Methods: Proliferating human RPE cells were exposed to varying concentrations of exogenous basic fibroblast growth factor (bFGF) or epidermal growth factor (EGF) at different media oxygen tensions (16 to 147 mm Hg) and cell counts determined after 4 days. Receptor expression was determined by affinity cross-linking and saturation binding studies on confluent RPE cultures exposed to varying media oxygen tensions for 2 days.

Dual immunodetection and hybridisation in situ of opsin mRNA and rhodopsin protein in retinal sections.

We describe a simple method for combining in situ hybridisation and immunohistochemistry on the same retinal section. The technique was developed using a radiolabelled cDNA probe for opsin and an antibody (ROS1F4) against rhodopsin. This method retains the antigenic sites if immunocytochemistry is performed prior to in situ hybridisation.