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Biomedical subjects

G Ramsay

Publications and source records attributed to G Ramsay.

At least 37 records · Page 2Linked to original sources
PubMed2000

Temperature-dependent germination traits in oilseed rape associated with 5'-anchored simple sequence repeat PCR polymorphisms.

An experiment was conducted to test the hypothesis that phenotypes differing in germination rate and the presence or absence of secondary dormancy at low temperature were not genetically different. Seed of oilseed rape was germinated at 4, 10 and 19 degrees C, where selections were made in the percentile ranges 1-10 (early), 45-55 (intermediate) and 91-100 (late). Secondary dormancy occurred only in the late selections at the two lower temperatures. Thermal weighting of curves of cumulative germination on time gave circumstantial evidence that early percentiles were similar at all three temperatures and that seeds with secondary dormancy came largely from later percentiles above the 50th. To test for genetic differentiation between phenotypes, 5'-anchored simple sequence repeat primers were used to generate DNA marker profiles of seedlings raised from seed from each category. Principal coordinate analysis, and more detailed comparisons using the most discriminating markers, confirmed that the early germinators at the three temperatures were not associated with different banding profiles, but seeds entering secondary dormancy, particularly at 10 degrees C, were genetically distinct from germinators at the same temperature. Secondary dormant seeds at low temperature appear to originate mainly from the late germinating seed at higher temperature. Effects of temperature history and the requirement for alternating temperatures to break secondary dormancy were quantified. The results confirm the existence of genetically discrete sub-populations differing in ecologically significant traits.

Brassica↗
PubMed2000

Decreased organ failure in patients with severe SIRS and septic shock treated with the platelet-activating factor antagonist TCV-309: a prospective, multicenter, double-blind, randomized phase II trial. TCV-309 Septic Shock Study Group.

Sepsis and organ failure remain the main cause of death on the ICU. Sepsis is characterized by a severe inflammatory response, in which platelet-activating factor (PAF) is considered to play an important role. This study investigated whether treatment with the PAF-antagonist TCV-309 reduces morbidity and mortality in patients with septic shock. The study was conducted as a double-blind, randomized, placebo controlled multicenter study. The included patients had to fulfill the SIRS criteria with a clinical suspicion of infection, an admission APACHE II score greater than 15, and shock, defined as a mean arterial pressure <70 mmHg and/or a decrease > or =40 mmHg despite adequate fluid resuscitation. Patients received 1.0 mg/kg TCV-309 or placebo, twice daily, intravenously during 14 days. The prospectively set goals were MOF score, recovery from shock, mortality, and assessment of the safety of the medication. A total of 98 patients were included of which 97 were analyzed on an intention-to-treat basis. The overall survival at day 56 of TCV-309 treated patients was similar compared to placebo treated patients (51.0% vs. 41.7%, P = 0.47). In contrast, the mean percentage of failed organs per patient present after 14 days in the TCV-309 treated patients was significantly lower compared to the placebo treated patients (11.9% vs. 25.1%, P = 0.04), leading to a reduced need for vasopressors, dialysis, and ventilatory support. Furthermore, the mean APACHE-II score during treatment with TCV-309 was significantly lower and the number of patients recovered from shock after day 14 was significantly higher in the TCV-309 treated patient group (2/32 vs. 9/29, P = 0.01). The number of adverse events was not significantly different between the TCV-309 and placebo treated patients. TCV-309 did not change overall mortality of septic shock, however a substantial reduction in organ dysfunction and morbidity, frequently associated with septic shock was achieved, without significant adverse events.

APACHE↗
PubMed2000

Development of vasomotor responses in fetal mesenteric arteries.

Changes in mesenteric arterial diameters were studied using intravital microscopy in chick fetuses at days 13 and 17 of incubation, corresponding to 0.6 and 0.8 fetal incubation time, both during 5 min of hypoxia followed by 5 min of reoxygenation and after topical administration of increasing concentrations (10(-6)-10(-2) M) of norepinephrine (NE) and acetylcholine (ACh). Baseline diameters of second-order mesenteric arteries increased from 56 microm at 0.6 incubation to 75 microm at 0.8 incubation. Acute hypoxia induced a reduction in arterial diameter to 87 +/- 4.4% of baseline at 0.6 incubation and to 44 +/- 6.7% at 0.8 incubation (P < 0.01). During reoxygenation, mesenteric arteries dilated to 118 +/- 6.5% and 121 +/- 7.5% of baseline at 0.6 and 0.8 fetal incubation time, respectively. Phentolamine did not affect the vasoconstriction during hypoxia at 0.6 incubation, whereas this alpha-adrenergic antagonist significantly attenuated the vasoconstrictor response at 0.8 incubation (to 93 +/- 2.7% of baseline, P < 0.01). Topical NE induced maximal vasoconstriction to 71 +/- 3% of baseline at 0.6 incubation and to 35 +/- 3.8% at 0.8 incubation (P < 0.01). Maximal vasodilation to topical ACh was 113 +/- 4.4% and 122 +/- 4.8% of baseline at 0.6 and 0.8 incubation, respectively. These in vivo findings show that fetal mesenteric arteries constrict in response to acute hypoxia and that the increase in magnitude of this vasoconstrictor response from 0.6 to 0.8 of fetal development results from an increase in adrenergic constrictor capacity.

Acetylcholine↗
PubMed1999

Utility of wiring nitrate reductase by alkylpyrroleviologen-based redox polymers for electrochemical biosensor and bioreactor applications.

The purpose of this work was to see if the alkylpyrroleviologen redox polymer technology previously developed for a reagentless nitrate biosensor based on nitrate reductase (NaR) from Escherichia coli (Cosnier, S.; Innocent, C.; Jouanneau, Y. Anal. Chem. 1994, 66, 3198-3201) could be applied to the isozyme from Aspergillus niger. In particular, the enzyme viability after immobilization was of great interest, as Cosnier et al. reported a residual activity of only 0.33% of the amount initially applied. The present work showed that A. niger NaR lost 99.2% of soluble activity on vacuum-drying in the presence of 2.5 nM N-methyl-N'-(12-[pyrrol-1-yl]dodecyl)-4,4'-bipyridinium ditetrafluoroborate monomer (C12V2+) and that most of this loss was due to monomer inhibition (91%). The loss due to dehydration was only 8%. In the biosensor configuration, the enzyme gave a residual activity of 0.18% of the amount originally applied and a specific response of 1.7 mA M-1 cm-2, but all activity was lost after 4 d storage at 4 degrees C in phosphate buffer. It was concluded that for practical biosensors and bioreactors, modification of the redox polymer format was needed, for example by covalent immobilization, to effect higher loading of viable NaR and improved enzyme stability.

Bioreactors↗
PubMed1999

Detection of non-infectious conditions mimicking pneumonia in the intensive care setting: usefulness of bronchoalveolar fluid cytology.

The present study investigated the usefulness of bronchoalveolar (BAL) fluid cytology in the identification of non-infectious pulmonary conditions in patients hospitalized in the intensive care unit (ICU) and suspected of pneumonia. A total of 182 BAL fluid samples obtained during a 27-month period from 130 ICU patients with suspected pneumonia were quantitatively cultured and investigated for opportunistic pathogens. Cytocentrifuged preparations stained with the May-Grünwald Giemsa and Perls's methods were reviewed. A non-infectious aetiology was considered when cultures yielded micro-organisms in quantities < 10(3) colony-forming units (CFU) per ml, in the absence of any other pathogen and in conjunction with one or more of the following cytological findings: > 20% haemosiderin macrophages, > 10% lymphocytes, the presence of activated lymphocytes, plasma cells, > 5% eosinophils, a preponderance of foamy macrophages, reactive type II pneumocytes or malignant cells. Patients' clinical records were reviewed to identify a clinical diagnosis for these episodes. In thirty-five (19.2%) BAL fluid samples from 26 patients, the cytological findings pointed to a non-infectious origin. An alternative diagnosis was ascertained in 20 of 26 patients. Diagnoses included: drug-induced pneumonitis (n = 7), aspiration of gastric contents (n = 2), pulmonary emboli (n = 3), adult respiratory distress syndrome (n = 4), lung contusion (n = 1), cardiogenic pulmonary oedema (n = 1), and carcinomatous lymphangitis (n = 2). The BAL fluid cytological findings were readily discernable and proved to be useful in the diagnostic work-up of samples obtained from ICU patients with suspected pneumonia.

Adult↗
PubMed1999

Prediction of postoperative cardiac surgical morbidity and organ failure within 4 hours of intensive care unit admission using esophageal Doppler ultrasonography.

OBJECTIVE: To compare esophageal Doppler ultrasonography with standard hemodynamic variables used in postoperative care for the prediction of postoperative complications after cardiac surgery. DESIGN: Prospective, observational pilot study. SETTING: University hospital, multidisciplinary intensive care unit PATIENTS: Postoperative cardiac surgical patients. INTERVENTIONS: Standard postoperative management as guided by routinely measured hemodynamic variables. MEASUREMENTS: An esophageal Doppler ultrasound probe was inserted for measurement of stroke volume (SV), cardiac output (CO), and other flow-related variables. Both these and routine hemodynamic variables (mean arterial pressure, central venous pressure, heart rate, arterial base deficit, urine output, core-toe temperature difference) were recorded at half-hourly intervals for the first 4 postoperative hrs. The incidence of systemic inflammatory response syndrome at 24 hrs, Acute Physiology and Chronic Health Evaluation II, and multiple organ failure scores, postoperative complications, and length of ICU and hospital stays were recorded. MAIN RESULTS: Twenty consecutively admitted patients were studied: eight after emergency bypass grafting and 12 after elective bypass grafts and/or valve replacement. Of the nine patients who developed postoperative complications, two died. At admission, significant differences were seen between patients with a complicated and those with an uncomplicated surgical procedure for SV, heart rate, and standard base excess, but not for cardiac output. By using receiver operator characteristic curves, SV was the best marker for predicting postoperative complications during the initial postoperative period. CONCLUSIONS: A low SV and a high heart rate, both at ICU admission and during the subsequent 4 hrs, were the best prognostic factors for development of complications after cardiac surgery. Cardiac output values were not useful. This pilot study suggests that the minimally invasive technique of esophageal Doppler ultrasonography may be a useful tool to assist early prognostication.

Analysis of Variance↗
PubMed1998

Drosophila myb is required for the G2/M transition and maintenance of diploidy.

The myb proto-oncogenes are thought to have a role in the cell division cycle. We have examined this possibility by genetic analysis in Drosophila melanogaster, which possesses a single myb gene. We have described previously two temperature-sensitive, recessive lethal mutants in Drosophila myb (Dm myb). The phenotypes of these mutants revealed a requirement for myb in diverse cellular lineages throughout the course of Drosophila development. We now report a cellular explanation for these findings by showing that Dm myb is required for both mitosis and prevention of endoreduplication in wing cells. Myb apparently acts at or near the time of the G2/M transition. The two mutant alleles of Dm myb produce the same cellular phenotype, although the responsible mutations are located in different functional domains of the gene product. The mutant phenotype can be partially suppressed by ectopic expression of either cdc2 or string, two genes that are known to promote the transition from G2 to M. We conclude that Dm myb is required for completion of cell division and may serve two independent functions: promotion of mitosis, on the one hand, and prevention of endoreduplication when cells are arrested in G2, on the other.

Amino Acid Sequence↗
PubMed1998

Intensive care training and specialty status in Europe: international comparisons. Task Force on Educational issues of the European Society of Intensive Care Medicine.

OBJECTIVE: To describe current arrangements for postgraduate training and speciality status for intensive care medicine in Europe, and to compare these with three other geographical regions: the Middle East, North America, and Australia and New Zealand. METHODS: An iterative survey, by questionnaire and direct discussion, of council members of the European Society of Intensive Care Medicine, national specialist societies with involvement in intensive care, and national experts, representing four geographical regions and 47 countries. RESULTS: For the purposes of analysis, countries with common training structures have been grouped together; the denominator therefore includes both countries and regions. Formal training programmes in intensive care medicine (ICM) are available in 18 (85%) of the 21 countries or regions surveyed. Twelve (57%) offer multidisciplinary access to intensive care training with a common core curriculum. In six (28%) training in ICM is available solely through anaesthesia. The duration of intensive care training required for recognition as a specialist in the 18 countries or regions with a formal programme ranges from 18 to 30 months, with a median of 24 months. All countries assess competence in intensive care, but methods for doing so vary widely. Eighteen countries or regions offer specialist registration (accreditation) in ICM; in 12 this is provided as dual accreditation in a base speciality and in ICM. CONCLUSIONS: There is substantial support for multidisciplinary training in ICM, as demonstrated by collaborative interspeciality developments in many countries. We propose that these national developments should be strengthened within Europe by the recognition of 'supra-speciality' status for ICM by the European Commission, and by the establishment of a multidisciplinary Board for training in ICM, with international agreement on core competencies and duration of training programmes, and a common approach to the assessment of competence through formal examination.

Accreditation↗
PubMed1998

Selective gut decontamination in intensive care and surgical practice: where are we?

Selective decontamination of the digestive tract (SDD) has been widely studied in the intensive care setting. Despite the publication of more than 50 controlled trials, it remains a controversial subject, with widely disparate views on the role of SDD. This article reviews the use of SDD primarily by examining the areas of controversy. The published data seem to show clear evidence that SDD can reduce acquired infection during intensive care. Most individual studies have shown no effect on mortality, but meta-analyses suggest a 10% overall reduction in mortality. Despite the large number of publications to date, there remain several aspects worthy of further study.

Bacterial Infections↗
PubMed1998

DNA chips: state-of-the art.

The technology and applications of microarrays of immobilized DNA or oligonucleotides are reviewed. DNA arrays are fabricated by high-speed robotics on glass or nylon substrates, for which labeled probes are used to determine complementary binding allowing massively parallel gene expression and gene discovery studies. Oligonucleotide microarrays are fabricated either by in situ light-directed combinational synthesis or by conventional synthesis followed by immobilization on glass substrates. Sample DNA is amplified by the polymerase chain reaction (PCR), and a fluorescent label is inserted and hybridized to the microarray. This technology has been successfully applied to the simultaneous expression of many thousands of genes and to large-scale gene discovery, as well as polymorphism screening and mapping of genomic DNA clones.

Animals↗
PubMed1998

Proinflammatory mediator activity, endogenous antagonists and the systemic inflammatory response in intra-abdominal sepsis. Scottish Sepsis Intervention Group.

BACKGROUND: Severe intra-abdominal sepsis continues to carry a high mortality rate. The physiological response to sepsis in this condition and its relationship with proinflammatory mediators and their endogenous antagonists require further clarification. METHODS: Fifty-seven patients were stratified by Acute Physiology And Chronic Health Evaluation (APACHE) II score at the time of admission to an intensive care unit (group 1, score of less than 20; group 2, score of 20 or more). Serial measurements of clinical and immunological variables were made. RESULTS: Non-survivors from group 2 had a raised acute physiology score (P = 0.01), a higher peak serum interleukin (IL) 6 concentration (P = 0.03) and a depressed level of endogenous immunoglobulin (Ig) G class antiendotoxin core antibody (P = 0.005). In group 1, although organ failure score increased progressively in non-survivors, physiology score and peak IL-6 level were similar to those in survivors, and endogenous IgG class antiendotoxin core antibody titre rose (P = 0.02). In both groups IL-1 and tumour necrosis factor alpha were detected infrequently, but their natural antagonists were present in much higher concentrations in both survivors and non-survivors. Levels of C-reactive protein were raised in both but were not significantly different between survivors and non-survivors. CONCLUSION: During the development of organ failure and death, the pattern of proinflammatory mediators and their endogenous antagonists can vary markedly and may in part be determined by the extent of the initial physiological disturbance.

Acute-Phase Reaction↗
PubMed1998

D-lactate as an early marker of intestinal ischaemia after ruptured abdominal aortic aneurysm repair.

BACKGROUND: Patients with a ruptured abdominal aortic aneurysm (AAA) are at risk of developing colonic ischaemia after surgery. It is difficult to diagnose this ischaemia at an early stage. D-lactate is produced by intestinal bacteria after ischaemia. L-lactate is released in increased amounts during hypoxia by anaerobic metabolism. This study investigated both variables as a marker for intestinal ischaemia in patients with a ruptured AAA. METHODS: Twenty-four patients with ruptured AAA were divided retrospectively into two groups with and without ischaemic complications, as verified by colonoscopy. Blood had been taken on admission to the intensive care unit (ICU). Median time to colonoscopy was 9 days after surgery. As controls, four patients with pneumonia, six healthy subjects, five patients with an elective AAA repair, and six patients with sepsis and acute tubular necrosis were included. RESULTS: D-lactate level on admission was significantly increased in patients with colonic ischaemia after ruptured AAA compared with the level in patients without ischaemia (P< 0.05), patients with sepsis (P< 0.001), those with pneumonia and healthy subjects (P< 0.01). L-lactate concentration was similar in the group with intestinal complications and in patients without colonic ischaemia; however, L-lactate levels were higher in patients with pneumonia and sepsis than in healthy subjects (P < 0.05). CONCLUSION: On admission to the ICU, D-lactate, but not L-lactate, levels may predict later colonic ischaemia following repair of a ruptured AAA.

Aged↗