PubMed Health⌕ Search

Biomedical subjects

S Douglas

Publications and source records attributed to S Douglas.

At least 19 recordsLinked to original sources
PubMed1995

Clinical characteristics and natural history of symptomatic but not excess gastroesophageal reflux.

Esophageal pH monitoring in patients with gastroesophageal reflux symptoms identifies some who have normal esophageal acid exposure but nevertheless a convincing correlation between symptoms and those reflux events that do occur. These patients may exhibit enhanced sensory perception of physiological reflux. Little is known about the natural history of reflux symptoms in this group, which in our experience comprises up to 6% of those referred for diagnostic pH monitoring. We have therefore followed up by postal questionnaire 70 patients whose initial pH study had demonstrated normal acid exposure but a symptom index > or = 50% and 58 patients found to have excess reflux, for a median of 4.4 and 6.5 years, respectively. The presenting character and frequency of symptoms and endoscopic and manometric findings were similar in the two groups. At review overall symptom frequency had improved (P < 0.01) for both groups similarly. However, 87% of those with normal acid exposure and 79% of those with excess reflux remained symptomatic, 53% and 47%, respectively, recording their symptoms to be the same or worse than at original presentation, despite over 60% in each group continuing to take regular medication. Only six patients in each group were asymptomatic and receiving no therapy at the time of review. The results demonstrate that patients with symptomatic but not excess gastroesophageal reflux constitute a significant clinical problem. Both the persistence of their symptoms and their requirement for therapy are similar to that observed in "genuine" refluxers.

Case-Control Studies↗
PubMed1995

Heightened visceral sensation in functional gastrointestinal disease is not site-specific. Evidence for a generalized disorder of gut sensitivity.

Alteration in visceral sensation locally at the site of presumed symptom origin in the gastrointestinal tract has been proposed as an important etiopathological mechanism in the so-called functional bowel disorders. Patients presenting with one functional gastrointestinal syndrome, however, frequently have additional symptoms referable to other parts of the gut, suggesting that enhanced visceral nociception may be a panintestinal phenomenon. We measured the sensory thresholds for initial perception (IP), desire to defecate (DD), and urgency (U) in response to rectal balloon distension, and the thresholds for initial perception and for discomfort in response to esophageal balloon distension in 12 patients with irritable bowel syndrome (IBS) and 10 patients with functional dyspepsia (FD), in comparison with healthy controls. As expected, IBS patients exhibited lower rectal sensory thresholds than controls (P < 0.0001), but in addition had significantly lower sensory thresholds for both perception and discomfort evoked by balloon distension of the esophagus (mean +/- SEM: 8.8 +/- 1.3 ml vs 12.1 +/- 1.5 ml (P < 0.05) and 12.2 +/- 1.4 ml vs 16.4 +/- 1.4 ml (P < 0.02) respectively. Patients with FD showed similarly enhanced esophageal sensitivity, with thresholds for perception and discomfort of 8.1 +/- 0.9 ml (P < 0.02), and 10.1 +/- 1.0 ml (p < 0.001), respectively, but were also found to have sensory thresholds for rectal distension similar to those observed in the IBS group, significantly lower than in controls: IP 45.0 +/- 17.6 vs 59.3 +/- 1.5 ml (P < 0.001), DD 98.0 +/- 17.9 vs 298.7 +/- 9.0 ml (P < 0.0001), U 177.2 +/- 25.4 vs 415.1 +/- 12.6 ml (p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

The cost-effectiveness of a special care unit to care for the chronically critically ill.

To assess the relative value of healthcare programs, technologic innovations, and clinical decisions, policymakers are searching for ways to evaluate cost-effectiveness. What constitutes cost-effectiveness and how should it be measured? The authors discuss ways in which the cost-effectiveness of clinical programs can be measured and describes various methods of assessing both costs and effectiveness. Comparison of the cost-effectiveness of a nurse managed special care unit with that of traditional intensive care units illustrates some of these methods.

Chronic Disease↗
PubMed1995

Evidence for a seasonal variation in the presentation of Hodgkins disease.

An analysis by month of diagnosis was made of 1359 cases of Hodgkins disease (HD) on the Scotland and Newcastle Lymphoma Group (SNLG) registry 1979-1992 to look for evidence of seasonality. A March peak was evident when all cases were analysed (p < 0.01). The histological subtypes nodular sclerosing (NS) and mixed cellularity (MC) showed a similar pattern (p < 0.05) while lymphocyte depleted (LD) and lymphocyte predominant (LP) had no demonstrable seasonal variation. In a breakdown by age and sex there was evidence of seasonality in both sexes but only under the age of 40. This provides further evidence for the heterogeneity of HD and supports the hypothesis that different factors are involved in the aetiology of this condition in younger compared to older patients.

Adolescent↗
PubMed1995

Twenty-four hour esophageal pH monitoring: technique and application.

In the last three decades, esophageal pH monitoring has progressed from an exclusively laboratory-based physiological research tool to a routine outpatient clinical investigation in patients with one of the most common gastrointestinal disorders. Technological advancement has considerably simplified both the procedure and the interpretation of data obtained, and there is currently reasonable consensus as to the parameters that best discriminate between physiological and pathological gastroesophageal reflux. There remains a need for internationally agreed definitions and standards, particularly with regard to calculation of these parameters, which would improve comparability of future research studies from different centers. Clinical applications of the technique have increased with our enhanced knowledge of the protean clinical manifestations of reflux disease. The advent of potent pharmacotherapy and the recognition of a need for ongoing treatment in many patients will ensure that the most sensitive test for the diagnosis of gastroesophageal reflux disease will remain an essential part of the investigation of upper gastrointestinal symptoms.

Esophagus↗
PubMed1994

The incidence of reporting consent rates in nursing research articles.

The study described the incidence of reporting consent rates (CRs) in nursing research articles, ascertained the mean CR for nursing research articles, ascertained differences between those studies that reported a CR and those that did not report a CR, and compared studies that used clinical populations to studies that used nonclinical populations. Research articles (371) from three nursing research journals were examined. Results showed that: (a) 40.7 percent of articles reported a CR, (b) the mean CR was 71.8 percent, (c) 41.1 percent reported inadequate CRs, (d) studies reporting a CR differed from those that did not on five of nine variables, and (e) studies employing clinical populations reported higher consent rates than did studies that employed nonclinical populations.

Bias↗
PubMed1993

Stabilization of von Willebrand factor in banked blood by leucocyte depletion.

The von Willebrand factor (vWf) activity, as measured by the ristocetin co-factor (vWf:RCo) and collagen binding (vWf:CBA) assays, declined progressively in standard blood units stored at 4 degrees C after a 2-day storage period. This loss of activity was accompanied by a loss and degradation of high molecular weight (HMW) vWf multimers. In studies using a paired design, filtration of blood with a high efficiency leucocyte-removal filter, prior to storage at 4 degrees C, led to significantly improved maintenance of vWf:RCo and vWf:CBA compared with unfiltered units (P < 0.01 after 8 days). Loss and degradation of HMW vWf decreased when blood was filtered prior to 4 degrees C storage. Filtration had no effect on vWf-associated activities when blood was stored at 22 degrees C for 10 days. These results indicate that part of the storage lesion of vWf in banked blood is due to leucocyte-mediated removal and degradation of HMW vWf. This has implications when specifying plasma for the production of vWF concentrates and may also play a role in the haemostatic lesion associated with massive transfusion of stored blood.

Blood Banks↗
PubMed1992

Modulation of fibrinogen content in cryoprecipitate by temperature manipulation during plasma processing.

In routine blood bank production of single-donation cryoprecipitate, the introduction of a 16-hour hold at 4 degrees C, with the frozen plasma units packed into polystyrene containers, resulted in plasma prethaw temperatures of -4 degrees C to -8 degrees C. This in turn resulted in cryoprecipitate fibrinogen levels that were 214 percent of those obtained when units were thawed immediately after removal from -30 degrees C storage. In scale-model production of factor VIII concentrate, plasma warmed from -30 to -10 to -15 degrees C over 18 hours before pooling and thawing yielded cryoprecipitate fibrinogen levels that were 66 percent of those found in plasma warmed to -2 to -5 degrees C over the same period. Processing -30 degrees C plasma without a warming period led to cryoprecipitate fibrinogen levels that were 40 percent of those obtained from plasma warmed to -2 to -5 degrees C. These differences were accentuated after purification of the cryoprecipitates to an intermediate-purity factor VIII concentrate. These results suggest that simple modifications in production methods allow the fibrinogen content of cryoprecipitate to be tailored to specific uses.

Blood Banks↗
PubMed1992

Red cell and platelet concentrates from blood collected into half-strength citrate anticoagulant: improved maintenance of red cell 2,3-diphosphoglycerate in half-citrate red cells.

This study confirms previous work suggesting equivalent in vitro properties in blood components prepared from donations collected into half-citrate preservative (HCPD) compared to components derived from donations collected into standard citrate-phosphate-dextrose (CPD) preservatives. In addition, red cell products harvested from HCPD donations showed significantly improved maintenance of pH over storage, and this was reflected in improved maintenance of intracellular 2,3-diphosphoglycerate (2,3-DPG). This effect was observed in whole blood and in red cells suspended in a phosphate-containing additive solution (Tuta AAS). Collection into HCPD also improved 2,3-DPG maintenance in red cell concentrates processed following an 18-hour hold at 22 degrees C. These improvements were less pronounced in red cells suspended in a non-phosphate-containing medium (Fenwal Adsol) in which a higher pH was maintained even in units collected in CPD. Platelets harvested from HCPD blood and suspended in plasma showed equivalent quality to platelets from standard donations. Some deterioration of platelet properties was observed when HCPD platelets were stored in a non-citrate synthetic medium. Together with data indicating improved coagulation factor stability, these results suggest that collection into HCPD improves stored blood quality and may also allow logistical benefits in blood component preparation.

2,3-Diphosphoglycerate↗
PubMed1992

Acute tubular necrosis: diagnosis, treatment, and nursing implications.

Acute tubular necrosis (ATN) is the most common cause of acute renal failure. Early recognition of patients who are at risk for ATN can prevent or improve the course of ATN. Acute renal failure is classified as prerenal, intrinsic, or postrenal disease. ATN is classified as a type of intrinsic renal disease. The clinical course of ATN is divided into the renal failure phase, diuretic phase, and recovery phase, with each phase having distinct symptoms and laboratory findings. Diagnosis of ATN often is complicated and confusing; understanding of laboratory findings can facilitate the critical care nurse's ability to assess those at risk for ATN. The care and treatment of the patient with ATN is complicated, and specific treatments are discussed in detail. The critical care nurse can play a vital role in identifying the patient at risk, preventing the development of ATN in those at risk, and providing appropriate care for those who develop ATN.

Humans↗
PubMed1990

Use of plasma with high levels of ionised calcium in the production of model scale coagulation factor concentrates.

We have attempted to exploit the Ca2(+)-dependent stability of factor VIII in producing factor VIII concentrates of higher yield. Plasma levels of ionised calcium were increased in two ways: (a) whole blood collection into half-strength citrate CPD anticoagulant, leading to free Ca2+ levels of ca 120 microM and (b) apheresis collection of plasma which was then recalcified to free Ca2+ levels of ca 300 microM under heparin cover. Coagulation factor concentrates were prepared using model versions of our industrial scale manufacturing methods. Factor VIII yield was increased through low citrate collection. This did not compromise factor IX yield or thrombogenic potential. Use of recalcified heparinised plasma did not lead to any improvement in factor VIII yield and resulted in a marked drop in factor IX recovery, possibly from interference by heparin of factor IX binding in ion-exchange chromatography. The benefits accruable through the use of half-strength citrate CPD anticoagulant support the continued evaluation of this preservative in large scale blood collection and fractionation. The deleterious effects of heparin in charge-mediated plasma fractionations may pose serious difficulties in harvesting vitamin K dependent factors.

Anticoagulants↗
PubMed1990

Localization of beta-phycoerythrin to the thylakoid lumen of Cryptomonas phi does not involve a signal peptide.

Recent investigations have shown that, in cryptomonads, the phycobiliproteins are located within the thylakoid lumen rather than on the stromal side of this membrane as found in cyanobacteria and red algae. To examine possible mechanisms involved in targeting this protein to the thylakoid lumen, the plastid-encoded cpeB gene from Cryptomonas phi was sequenced. This gene encodes an open reading frame of 177 amino acids that is highly similar to known beta-phycoerythrin proteins. cpeB is expressed as a monocistronic transcript of approximately 680 bases. The genes for the alpha subunits of phycoerythrin are not co-transcribed with cpeB nor located anywhere near it. No evidence of amino- or carboxy-terminal extensions or interior modifications involved in directing the Cryptomonas beta-phycoerythrin into the lumen of the thylakoid could be detected. These data suggest that a novel mechanism may be involved in directing cryptomonad biliproteins to the thylakoid lumen.

Amino Acid Sequence↗
PubMed1989

Oral health promotion for institutionalised elderly.

The purpose of the present study was to develop and evaluate educational approaches specifically for improvement of oral hygiene behaviour amongst institutionalised elderly. A sample of 201 residents, 48-99 yr of age (mean age 82 yr), was selected from four different institutions in Lothian, Scotland. A clinical examination and a structured interview were conducted immediately before and 2 months after the termination of the programme. The four institutions were blind to the examiner and randomly allocated to a control group or one of the three programmes; 1) active involvement of staff only; 2) active involvement of residents only; 3) active involvement of both residents and staff. The programme comprised three 1-h sessions at monthly intervals in groups of five to six residents or members of staff. The analysis of the results showed poor oral health and oral hygiene, high objective need for oral care but low perceived need. The programme had little impact on most of the included variables and only about half of the participants remembered the programme 2 months after its termination. The implications of the study are that groups of elderly need to be differentiated further so that only well and not confused elderly participate in programmes such as this and less well and confused elderly receive regular professional support with oral hygiene.

Aged↗
PubMed1989

Microtitre plate measurement of platelet response to hypotonic stress.

The conventional method of assessing the platelet response to hypotonic stress (HSR) was adapted to allow microtitre plate technology to be used. After water is added to a platelet suspension two sequential readings are taken at 414 nM on a vertical microplate reader. The difference between the second (three minutes) and the first (one minute) was defined as the HSR. This method allowed the relation between platelet concentrate pH and viability to be confirmed, and an HSR value for use in quality control was established. The method correlated well with the conventional technique and permitted measurement of undiluted samples as well as of products with a high free haemoglobin concentration.

Blood Platelets↗