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Biomedical subjects

J E Gray

Publications and source records attributed to J E Gray.

At least 19 recordsLinked to original sources

Systemic signalling of environmental cues in Arabidopsis leaves.

Light intensity and atmospheric CO2 partial pressure are two environmental signals known to regulate stomatal numbers. It has previously been shown that if a mature Arabidopsis leaf is supplied with either elevated CO2 (750 ppm instead of ambient at 370 ppm) or reduced light levels (50 micromol m-2 s-1 instead of 250 micromol m-2 s-1), the young, developing leaves that are not receiving the treatment grow with a stomatal density as if they were exposed to the treatment. But the signal(s) that it is believed is generated in the mature leaves and transmitted to developing leaves are largely unknown. Photosynthetic rates of treated, mature Arabidopsis leaves increased in elevated CO2 and decreased when shaded, as would be expected. Similarly, the levels of sugars (glucose, fructose, and sucrose) in the treated mature leaves increased in elevated CO2 and decreased with shade treatment. The levels of sugar in developing leaves were also measured and it was found that they mirrored this result even though they were not receiving the shade or elevated CO2 treatment. To investigate the effect of these treatments on global gene expression patterns, transcriptomics analysis was carried out using Affymetrix, 22K, and ATH1 arrays. Total RNA was extracted from the developing leaves after the mature leaves had received either the ambient control treatment, the elevated CO2 treatment, or the shade treatment, or both elevated CO2 and shade treatments for 2, 4, 12, 24, 48, or 96 h. The experiment was replicated four times. Two other experiments were also conducted, one to compare and contrast gene expression in response to plants grown at elevated CO2 and the other to look at the effect of these treatments on the mature leaf. The data were analysed and 915 genes from the untreated, signalled leaves were identified as having expression levels affected by the shade treatment. These genes were then compared with those whose transcript abundance was affected by the shade treatment in the mature treated leaves (1181 genes) and with 220 putative 'stomatal signalling' genes previously identified from studies of the yoda mutant. The results of these experiments and how they relate to environmental signalling are discussed, as well as possible mechanisms for systemic signalling.

Acclimatization↗

Real time patient safety audits: improving safety every day.

BACKGROUND: Timely error detection including feedback to clinical staff is a prerequisite for focused improvement in patient safety. Real time auditing, the efficacy of which has been repeatedly demonstrated in industry, has not been used previously to evaluate patient safety. Methods successful at improving quality and safety in industry may provide avenues for improvement in patient safety. OBJECTIVE: Pilot study to determine the feasibility and utility of real time safety auditing during routine clinical work in an intensive care unit (ICU). METHODS: A 36 item patient safety checklist was developed via a modified Delphi technique. The checklist focused on errors associated with delays in care, equipment failure, diagnostic studies, information transfer and non-compliance with hospital policy. Safety audits were performed using the checklist during and after morning work rounds thrice weekly during the 5 week study period from January to March 2003. RESULTS: A total of 338 errors were detected; 27 (75%) of the 36 items on the checklist detected >or=1 error. Diverse error types were found including unlabeled medication at the bedside (n = 31), ID band missing or in an inappropriate location (n = 70), inappropriate pulse oximeter alarm setting (n = 22), and delay in communication/information transfer that led to a delay in appropriate care (n = 4). CONCLUSIONS: Real time safety audits performed during routine work can detect a broad range of errors. Significant safety problems were detected promptly, leading to rapid changes in policy and practice. Staff acceptance was facilitated by fostering a blame free "culture of patient safety" involving clinical personnel in detection of remediable gaps in performance, and limiting the burden of data collection.

Delphi Technique↗

Is mandatory outpatient treatment effective?

This paper reviews the major studies of mandatory outpatient treatment (MOT) and examines why there has been inconsistency in some of the findings. Attempts to answer the question "is mandatory treatment effective?" must first clarify the type of mandatory treatment being examined, the type of patient being treated, and the outcome by which effectiveness is measured. There is consistent evidence that various forms of MOT increase follow-up with psychiatric services and that court-ordered outpatient committal decreases victimization of patients in the community. It also appears likely that MOT reduces the use of hospitalization; but, due to methodological problems associated with the research, this conclusion remains controversial.

Ambulatory Care↗

Biological efficacy of electroless-deposited silver on plasma activated polyurethane.

Silver coating of catheters has been shown to have inhibitory effects on bacterial growth and adhesion to catheter surfaces. In this study, plasma-modification was used to enhance the adhesion of an electroless silver coating on polyurethane. Both the antibacterial and antiadhesive properties of these coatings were investigated. Bacterial growth was inhibited in cultures exposed to silver-treated polyurethane compared to unmodified polyurethane. Higher growth inhibition was observed for polyurethane surfaces with lower silver coverage. Bacterial adhesion was completely inhibited on all silver-coated surfaces.

Anti-Bacterial Agents↗

ABA signalling: a messenger's FIERY fate.

There is considerable circumstantial evidence that the Ca(2+)-mobilizing second messenger IP(3) is involved in plant responses to the drought hormone abscisic acid. More direct evidence for this has now come from studies in which endogenous IP(3) levels have been manipulated in plants.

Abscisic Acid↗

Ripening-related occurrence of phosphoenolpyruvate carboxykinase in tomato fruit.

Phosphoenolpyruvate carboxykinase (PEPCK) is present in ripening tomato fruits. A cDNA encoding PEPCK was identified from a PCR-based screen of a cDNA library from ripe tomato fruit. The sequence of the tomato PEPCK cDNA and a cloned portion of the genomic DNA shows that the complete cDNA sequence contains an open reading frame encoding a peptide of 662 amino acid residues in length and predicts a polypeptide with a molecular mass of 73.5 kDa, which corresponds to that detected by western blotting. Only one PEPCK gene was identified in the tomato genome. PEPCK is shown to be present in the pericarp of ripening tomato fruits by activity measurements, western blotting and mRNA analysis. PEPCK abundance and activity both increased during fruit ripening, from an undetectable amount in immature green fruit to a high amount in ripening fruit. PEPCK mRNA, protein and activity were also detected in germinating seeds and, in lower amounts, in roots and stems of tomato. The possible role of PEPCK in the pericarp of tomato fruit during ripening is discussed.

Amino Acid Sequence↗

Clinically significant differences among Canadian mental health acts.

OBJECTIVES: First, to highlight the major differences among mental health acts in different Canadian jurisdictions as they relate to involuntary admission criteria, treatment authorization, review and appeal procedures, and conditional leave and community treatment orders. Second, to analyze the impact of these differences on the care that individuals with mental illness receive. METHOD: We examined the mental health act provisions of all Canadian jurisdictions to determine how the clinical management of a typical case would differ among jurisdictions. We used a statement of principles for mental health legislation endorsed by the Canadian Psychiatric Association to guide the analysis. We confirmed interpretation of each act and its implementation through key informant contact in each province and territory. RESULTS: We found clinically significant differences among the provinces and territories on all major components of their mental health acts. CONCLUSION: Provisions that prevent patients receiving appropriate clinical care can be found in some Canadian mental health acts. Alternate provisions that support appropriate clinical care, that respect the human rights and personal dignity of patients, and that are consistent with the Canadian Charter of Rights and Freedoms can be found in the legislation of other jurisdictions.

Canada↗

The HIC signalling pathway links CO2 perception to stomatal development.

Stomatal pores on the leaf surface control both the uptake of CO2 for photosynthesis and the loss of water during transpiration. Since the industrial revolution, decreases in stomatal numbers in parallel with increases in atmospheric CO2 concentration have provided evidence of plant responses to changes in CO2 levels caused by human activity. This inverse correlation between stomatal density and CO2 concentration also holds for fossil material from the past 400 million years and has provided clues to the causes of global extinction events. Here we report the identification of the Arabidopsis gene HIC (for high carbon dioxide), which encodes a negative regulator of stomatal development that responds to CO2 concentration. This gene encodes a putative 3-keto acyl coenzyme A synthase--an enzyme involved in the synthesis of very-long-chain fatty acids. Mutant hic plants exhibit up to a 42% increase in stomatal density in response to a doubling of CO2. Our results identify a gene involved in the signal transduction pathway responsible for controlling stomatal numbers at elevated CO2.

Algal Proteins↗

Distribution, speciation, and transport of mercury in stream-sediment, stream-water, and fish collected near abandoned mercury mines in southwestern Alaska, USA.

Concentrations of total Hg, Hg (II), and methylmercury were measured in stream-sediment, stream-water, and fish collected downstream from abandoned mercury mines in southwestern Alaska to evaluate environmental effects to surrounding ecosystems. These mines are found in a broad belt covering several tens of thousands of square kilometers, primarily in the Kuskokwim River basin. Mercury ore is dominantly cinnabar (HgS), but elemental mercury (Hg degrees) is present in ore at one mine and near retorts and in streams at several mine sites. Approximately 1400 t of mercury have been produced from the region, which is approximately 99% of all mercury produced from Alaska. These mines are not presently operating because of low prices and low demand for mercury. Stream-sediment samples collected downstream from the mines contain as much as 5500 microg/g Hg. Such high Hg concentrations are related to the abundance of cinnabar, which is highly resistant to physical and chemical weathering, and is visible in streams below mine sites. Although total Hg concentrations in the stream-sediment samples collected near mines are high, Hg speciation data indicate that concentrations of Hg (II) are generally less than 5%, and methylmercury concentrations are less than 1% of the total Hg. Stream waters below the mines are neutral to slightly alkaline (pH 6.8-8.4), which is a result of the insolubility of cinnabar and the lack of acid-generating minerals such as pyrite in the deposits. Unfiltered stream-water samples collected below the mines generally contain 500-2500 ng/l Hg; whereas, corresponding stream-water samples filtered through a 0.45-microm membrane contain less than 50 ng/l Hg. These stream-water results indicate that most of the Hg transported downstream from the mines is as finely-suspended material rather than dissolved Hg. Mercury speciation data show that concentrations of Hg (II) and methylmercury in stream-water samples are typically less than 22 ng/l, and generally less than 5% of the total Hg. Muscle samples of fish collected downstream from mines contain as much as 620 ng/g Hg (wet wt.), of which 90-100% is methylmercury. Although these Hg concentrations are several times higher than that in fish collected from regional baseline sites, the concentration of Hg in fish is below the 1000 ng/g action level for edible fish established by the US Food and Drug Administration (FDA). Salmon contain less than 100 ng/g Hg, which are among the lowest Hg contents observed for fish in the study, and well below the FDA action level.

Alaska↗

Occurrence of nosocomial bloodstream infections in six neonatal intensive care units.

BACKGROUND: Nosocomial bloodstream infections (NBSIs) occur frequently in neonatal intensive care units (NICUs) and are associated with substantial morbidity and mortality. Little has been published regarding variation in NBSI among institutions. OBJECTIVE: To determine NBSI incidence among six NICUs and to explore how much variation is explained by patient characteristics and NICU practice patterns. METHODS: From October, 1994, to June, 1996, six regional NICUs prospectively abstracted clinical records of all neonates weighing <1,500 g. Occurrence of NBSI, defined as first positive culture occurring >48 h after admission, was analyzed in relation to baseline patient characteristics and several common therapeutic interventions. Variables significant in univariate analyses were analyzed by Cox proportional hazards regression. RESULTS: There were 258 NBSIs (incidence, 19.1%) among 1,354 inborn first admissions. Incidence varied significantly by site, from 8.5 to 42%. Birth weight, Broviac catheter use and parenteral nutrition were significantly associated with NBSI (P < 0.05). When controlling for these variables interinstitutional variation in NBSI occurrence decreased but remained significant. CONCLUSIONS: Neonatal NBSI incidence varies substantially among institutions despite adjustment for length of stay and some known risk factors. The uses of Broviac catheters and especially intravenous nutrition supplements were significant determinants of NBSI risk.

Analysis of Variance↗

Medical physics: some recollections in diagnostic X-ray imaging and therapeutic radiology.

Medical physics has changed dramatically since 1895. There was a period of slow evolutionary change during the first 70 years after Roentgen's discovery of x rays. With the advent of the computer, however, both diagnostic and therapeutic radiology have undergone rapid growth and changes. Technologic advances such as computed tomography and magnetic resonance imaging in diagnostic imaging and three-dimensional treatment planning systems, stereotactic radiosurgery, and intensity modulated radiation therapy in radiation oncology have resulted in substantial changes in medical physics. These advances have improved diagnostic imaging and radiation therapy while expanding the need for better educated and experienced medical physics staff.

Certification↗

Baby CareLink: using the internet and telemedicine to improve care for high-risk infants.

OBJECTIVE: To evaluate an Internet-based telemedicine program designed to reduce the costs of care, to provide enhanced medical, informational, and emotional support to families of very low birth weight (VLBW) infants during and after their neonatal intensive care unit (NICU) stay. BACKGROUND: Baby CareLink is a multifaceted telemedicine program that incorporates videoconferencing and World Wide Web (WWW) technologies to enhance interactions between families, staff, and community providers. The videoconferencing module allows virtual visits and distance learning from a family's home during an infant's hospitalization as well as virtual house calls and remote monitoring after discharge. Baby CareLink's WWW site contains information on issues that confront these families. In addition, its security architecture allows efficient and confidential sharing of patient-based data and communications among authorized hospital and community users. DESIGN/METHODS: A randomized trial of Baby CareLink was conducted in a cohort of VLBW infants born between November 1997 and April 1999. Eligible infants were randomized within 10 days of birth. Families of intervention group infants were given access to the Baby CareLink telemedicine application. A multimedia computer with WWW browser and videoconferencing equipment was installed in their home within 3 weeks of birth. The control group received care as usually practiced in this NICU. Quality of care was assessed using a standardized family satisfaction survey administered after discharge. In addition, the effect of Baby CareLink on hospital length of stay as well as family visitation and interactions with infant and staff were measured. RESULTS: Of the 176 VLBW infants admitted during the study period, 30 control and 26 study patients were enrolled. The groups were similar in patient and family characteristics as well as rates of inpatient morbidity. The CareLink group reported higher overall quality of care. Families in the CareLink group reported significantly fewer problems with the overall quality of care received by their family (mean problem score: 3% vs 13%). In addition, CareLink families also reported greater satisfaction with the unit's physical environment and visitation policies (mean problem score: 13% vs 50%). The frequency of family visits, telephone calls to the NICU, and holding of the infant did not differ between groups. The duration of hospitalization until ultimate discharge home was similar in the 2 groups (68.5 +/- 28.3 vs 70.6 +/- 35.6 days). Among infants born weighing <1000 g (n = 31) there was a tendency toward shorter lengths of stay (77.4 +/- 26.2 vs 93.1 +/- 35.6 days). All infants in the CareLink group were discharged directly to home whereas 6/30 (20%) of control infants were transferred to community hospitals before ultimate discharge home. CONCLUSIONS: CareLink significantly improves family satisfaction with inpatient VLBW care and definitively lowers costs associated with hospital to hospital transfer. Our data suggest the use of telemedicine and the Internet support the educational and emotional needs of families facilitating earlier discharge to home of VLBW infants. We believe that further extension of the Baby CareLink model to the postdischarge period will significantly improve the coordination and efficiency of care.

Aftercare↗

Ca2+signalling in stomatal guard cells.

Ca(2+) is a ubiquitous second messenger in the signal transduction pathway(s) by which stomatal guard cells respond to external stimuli. Increases in guard-cell cytosolic free Ca(2+) concentration ([Ca(2+)](cyt)) have been observed in response to stimuli that cause both stomatal opening and closure. In addition, several important components of Ca(2+)-based signalling pathways have been identified in guard cells, including the cADP-ribose and phospholipase C/Ins(1, 4,5)P(3)-mediated Ca(2+)-mobilizing pathways. The central role of stimulus-induced increases in [Ca(2+)](cyt) in guard-cell signal transduction has been clearly demonstrated in experiments examining the effects of modulating increases in [Ca(2+)](cyt) on alterations in guard-cell turgor or the activity of ion channels that act as effectors in the guard-cell turgor response. In addition, the paradox that Ca(2+) is involved in the transduction of signals that result in opposite end responses (stomatal opening and closure) might be accounted for by the generation of stimulus-specific Ca(2+) signatures, such that increases in [Ca(2+)](cyt) exhibit unique spatial and temporal characteristics.

Adenosine Diphosphate Ribose↗

Abscisic acid induces oscillations in guard-cell cytosolic free calcium that involve phosphoinositide-specific phospholipase C.

Oscillations in cytosolic free Ca2+ concentration ([Ca2+]cyt) are an important component of Ca2+-based signal transduction pathways. This fact has led us to investigate whether oscillations in [Ca2+]cyt are involved in the response of stomatal guard cells to the plant hormone abscisic acid (ABA). We show that ABA induces oscillations in guard-cell [Ca2+]cyt. The pattern of the oscillations depended on the ABA concentration and correlated with the final stomatal aperture. We examined the mechanism by which ABA generates oscillations in guard-cell [Ca2+]cyt by using 1-(6-[17beta-3-methoxyestra-1,3, 5(10)-trien-17-yl]aminohexyl)-1H-pyrrole-2,5-dione (U-73122), an inhibitor of phosphoinositide-specific phospholipase C (PI-PLC)-dependent processes in animals. U-73122 inhibited the hydrolysis of phosphatidylinositol 4,5-bisphosphate by a recombinant PI-PLC, isolated from a guard-cell-enriched cDNA library, in a dose-dependent manner. This result confirms that U-73122 is an inhibitor of plant PI-PLC activity. U-73122 inhibited both ABA-induced oscillations in [Ca2+]cyt and stomatal closure. In contrast, U-73122 did not inhibit external Ca2+-induced oscillations in guard-cell [Ca2+]cyt and stomatal closure. Furthermore, there was no effect of the inactive analogue 1-(6-[17beta-3-methoxyestra-1,3, 5(10)-trien-17-yl]aminohexyl)-2,5-pyrrolidinedione on recombinant PI-PLC activity or ABA-induced and external Ca2+-induced oscillations in [Ca2+]cyt and stomatal closure. This lack of effect suggests that the effects of U-73122 in guard cells are the result of inhibition of PI-PLC and not a consequence of nonspecific effects. Taken together, our data suggest a role for PI-PLC in the generation of ABA-induced oscillations in [Ca2+]cyt and point toward the involvement of oscillations in [Ca2+]cyt in the maintenance of stomatal aperture by ABA.

Journal Article↗