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Biomedical subjects

I Roberts

Publications and source records attributed to I Roberts.

At least 109 records · Page 6Linked to original sources
PubMed1999

Simple, but not branched, plasmodesmata allow the nonspecific trafficking of proteins in developing tobacco leaves.

Leaves undergo a sink-source transition during which a physiological change occurs from carbon import to export. In sink leaves, biolistic bombardment of plasmids encoding GFP-fusion proteins demonstrated that proteins with an Mr up to 50 kDa could move freely through plasmodesmata. During the sink-source transition, the capacity to traffic proteins decreased substantially and was accompanied by a developmental switch from simple to branched forms of plasmodesmata. Inoculation of sink leaves with a movement protein-defective virus showed that virally expressed GFP, but not viral RNA, was capable of trafficking between sink cells during infection. Contrary to dogma that plasmodesmata have a size exclusion limit below 1 kDa, the data demonstrate that nonspecific "macromolecular trafficking" is a general feature of simple plasmodesmata in sink leaves.

Biological Transport↗
PubMed1999

Novel method for the production of multiple colour chromosome paints for use in karyotyping by fluorescence in situ hybridisation.

The development of 24-colour fluorescence in situ hybridisation (FISH) has led to significant advances in cytogenetic research and offers the potential for automated karyotypic analysis. However, these techniques are not in routine research or clinical use because of limitations in methods of probe preparation. This article presents new probe construction protocols and strategies for multiple-colour karyotyping by chromosome painting, which makes the technique more efficient and may lead to more widespread implementation. We used paints generated by our protocols to demonstrate the presence of a cryptic translocation t(13;11;22) in the paediatric sarcoma cell line RMS 1598.

Chromosome Painting↗
PubMed1999

Smoke alarm installation and function in inner London council housing.

AIM: To determine the prevalence of and predictors for installed, functioning smoke alarms in council (public) housing in a low income, multi-ethnic urban area. DESIGN: Cross sectional study. SETTING: 40 materially deprived electoral wards in two inner London boroughs. PARTICIPANTS: Occupants of 315 addresses randomly selected from council housing lists, with 75% response rate. MAIN OUTCOME MEASURES: Installation and function of smoke alarms based on inspection and testing. RESULTS: 39% (95% confidence interval (CI) 33% to 46%) of council tenants owned a smoke alarm, 31% (95% CI 25% to 38%) had an installed alarm (of which 54% were correctly installed), and 16% (95% CI 12% to 22%) had at least one installed, functioning alarm. Alarms most commonly failed because they lacked batteries (72%). In multivariate modelling, having an installed, functioning alarm was most strongly associated with living in a house versus a flat (apartment) (odds ratio (OR) 3.2, 95% CI 1.1 to 10.0), having two resident adults versus one (OR 2.8, 95% CI 1.2 to 6.5), and recognising stills from a Home Office television smoke alarm campaign (OR 2.4, 95% CI 1.1 to 5.5). CONCLUSIONS: Fires are a leading cause of child injury and death, particularly among those younger than 5 years of age and those in social classes IV and V. Smoke alarms are associated with a significantly reduced risk of death in residential fires, and are more protective in households with young children. Few council properties in a multi-ethnic, materially deprived urban area had any installed, functioning smoke alarms, despite a high risk of residential fires and fire related injuries in such areas. Effective methods to increase the prevalence of installed and functioning alarms must be identified.

Accident Prevention↗
PubMed1999

The "Let's Get Alarmed!" initiative: a smoke alarm giveaway programme.

OBJECTIVES: To reduce fires and fire related injuries by increasing the prevalence of functioning smoke alarms in high risk households. SETTING: The programme was delivered in an inner London area with above average material deprivation and below average smoke alarm ownership. The target population included low income and rental households and households with elderly persons or young children. METHODS: Forty wards, averaging 4000 households each, were randomised to intervention or control status. Free smoke alarms and fire safety information were distributed in intervention wards by community groups and workers as part of routine activities and by paid workers who visited target neighbourhoods. Recipients provided data on household age distribution and housing tenure. Programme costs were documented from a societal perspective. Data are being collected on smoke alarm ownership and function, and on fires and related injuries and their costs. RESULTS: Community and paid workers distributed 20,050 smoke alarms, potentially sufficient to increase smoke alarm ownership by 50% in intervention wards. Compared with the total study population, recipients included greater proportions of low income and rental households and households including children under 5 years or adults aged 65 and older. Total programme costs were 145,087 Pounds. CONCLUSIONS: It is possible to implement a large scale smoke alarm giveaway programme targeted to high risk households in a densely populated, multicultural, materially deprived community. The programme's effects on the prevalence of installed and functioning alarms and the incidence of fires and fire related injuries, and its cost effectiveness, are being evaluated as a randomized controlled trial.

Adolescent↗
PubMed1999

Nitric oxide synthase inhibition and delayed cerebral injury after severe cerebral ischemia in fetal sheep.

After transient cerebral ischemia in fetal sheep, delayed disruptions in cerebral energetics are represented by a delayed increase in cortical impedance, a progressive decrease in the concentration of oxidized cytochrome oxidase as measured by near-infrared spectroscopy, and cortical seizures. Because the production of nitric oxide (NO), a potent mediator of neuronal death, is increased during this phase, the present study investigated whether inhibition of NO synthesis could ameliorate the delayed disruption in cerebral energetics. Eleven late gestation fetal sheep were subjected to 30 min of transient cerebral ischemia in utero. Two hours later, the treatment group (n = 5) received a continuous infusion of N(G)-nitro-L-arginine, a competitive inhibitor of NO synthase, whereas the control group (n = 6) received PBS. Changes in concentration of oxidized cytochrome oxidase, cortical impedance, and electrocortical activity were observed for 3 d. A delayed increase in cortical impedance of similar magnitude and duration commenced at 14+/-4 h in the control and at 15+/-3 h in the treatment groups. The progressive decrease in oxidized cytochrome oxidase signal, by -2.2+/-0.2 micromol/L in the control and -2.0+/-0.4 micromol/L in the treatment group at 72 h postischemia, was similar in both groups. In both groups, delayed cortical seizures were indicated by intense low-frequency electrocortical activity. In the treatment group, duration of cortical seizures was increased and the intensity of the final electrocortical activity was more depressed (-19+/-1 dB versus -10+/-2 dB). The results indicate that after cerebral ischemia in fetal sheep, NO synthase inhibition does not ameliorate the delayed disruptions in cerebral energetics. However, the effect of NO synthase inhibition on delayed cortical seizures may improve our understanding of the role of NO during this phase.

Animals↗
PubMed1999

Hypopharyngeal perforation from a swallowed fork: a brief report and comment.

Hypopharyngeal perforations are usually seen as a complication of endotracheal intubation by less experienced physicians in emergency situations. The site most commonly perforated is the pharynx, posterior to the cricopharyngeal muscle; the second most common site is the pyriform sinus. We report here an unusual cause of hypopharyngeal perforation from a swallowed plastic fork in a psychiatric patient.

Adult↗
PubMed1998

Homozygous deletions at 3p12 in breast and lung cancer.

We have constructed a physical map of the region homozygously deleted in the U2020 cell line at 3p12, including the location of putative CpG islands. Adjacent to one of these islands, we have identified and cloned a new gene (DUTT1) and used probes from this gene to detect two other homozygous deletions occurring in lung and breast carcinomas: the smallest deletion is within the gene itself and would result in a truncated protein. The DUTT1 gene is a member of the neural cell adhesion molecule family, although its widespread expression suggests it plays a less specialized role compared to other members of the family.

Breast Neoplasms↗