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Biomedical subjects

D Calder

Publications and source records attributed to D Calder.

At least 19 recordsLinked to original sources
PubMed2005

Pathogenic Acanthamoeba strains from water sources in Jamaica, West Indies.

In 2004, samples of tap water and of river and sea water associated with human activities were collected in Jamaica, West Indies, and checked for free-living Acanthamoeba. The morphologies of the cysts and trophozoites observed and the results of PCR-based amplifications with a genus-specific primer pair were used to identify the Acanthamoeba isolates. The potential of each isolate as a human pathogen was then evaluated using thermotolerance and osmotolerance assays and two PCR-based assays for Acanthamoeba pathogenesis. Acanthamoeba were identified in 36.1%, 26.4% and 49.6% of the tap-, river- and sea-water samples collected, respectively. Pathogenic potential was shown by 60.0% of the Acanthamoeba strains isolated from tap water, 68.4% of the strains from river water, and 40.4% of the seawater strains. Sequencing of ribosomal DNA revealed the T1, T2, T4, T5, T7, T9 and T11 genotypes. Isolates of the T4 genotype were collected from tap, rain and sea water and, as expected, exhibited the most pathogenic traits; most were osmotolerant, thermotolerant and expressing extracellular serine protease. This is the first study of the occurrence and distribution of Acanthamoeba in water in the West Indies, and the results confirm the presence of potentially pathogenic strains in Jamaica.

Acanthamoeba↗
PubMed2002

Functional outcome following excision of tumours of the distal radius and reconstruction by autologous non-vascularized osteoarticular fibula grafting.

The distal radius and its articulations clearly have a vital role in the functional abilities of the hand and wrist. The treatment of tumours of the radius, therefore, needs to achieve satisfactory clearance of the lesions while also preserving as much wrist function as possible. We have employed osteoarticular autologous fibula grafts to reconstitute the distal radius after tumour excision. Since 1992, 13 patients have been treated by this technique for tumours of the distal radius. The group comprised patients with primary and recurrent giant cell tumours of bone, osteosarcoma, chondrosarcoma and Ewing's tumour. This technique achieves a satisfactory functional result without compromise of the prognosis for the tumour.

Adult↗
PubMed1997

Nutritional homeostasis in locusts: is there a mechanism for increased energy expenditure during carbohydrate overfeeding?

Maintenance of carbohydrate balance via changes in CO2 output volume was investigated in locusts using a flow-through respirometer. The effect of an imbalance in the dietary protein to digestible carbohydrate ratio on expired CO2 levels was measured in locusts fed one of two synthetic diets [7% protein, 21% digestible carbohydrate (7:21) and 21% protein, 7% digestible carbohydrate (21:7)]. Additionally, the effect of dietary dilution was investigated by feeding locusts one of two diets with a close-to-optimal ratio of protein to carbohydrate, one containing 7% protein and 7% digestible carbohydrate (7:7) and the other containing 21% protein and 21% digestible carbohydrate (21:21). For insects fed unbalanced diets, a higher CO2 output volume was measured during feeding on diet 7:21 when compared with insects fed on diet 21:7. Locusts also expired a greater volume of CO2 during the entire 2h observation period. This response is consistent with specific metabolic control of carbohydrate balance via enhanced respiration. For insects fed balanced diets, the total volume of CO2 expired over the duration of a meal was greater for insects fed diet 7:7 than for those fed diet 21:21, although this was due entirely to meals lasting longer on the more dilute diet. However, the basal level of respiration rate was greater for insects fed diet 21:21 and, as a result, over the entire 2h period, CO2 output volume did not differ between locusts fed diet 7:7 or 21:21. A possible mechanism for enhanced CO2 output volume on the nutritionally unbalanced diet was investigated, namely triglyceride/fatty-acid substrate cycling. There was no evidence for the presence of the thermogenic effect of this particular cycle on locusts as a means for dealing with excess ingested carbohydrate.

Journal Article↗
PubMed1995

Washout and redistribution between immediate and two-hour myocardial images using technetium-99m sestamibi.

The aim of this study was to assess whether a clinically relevant change in myocardial sestamibi activity could be documented within the first 120 min following injection (p.i.). In 17 patients planar anterior imaging of the heart was performed 5 min and 120 min p.i. During this time interval, mean decay-corrected myocardial activity declined to 77.9% +/- 9.7% after stress and to 85.7% +/- 7.9% after injection at rest (P < 0.05). In 19 patients with angiographically documented coronary artery disease, single-photon emission tomography was performed 5 min and 120 min after injection at maximum stress. For analysis, sestamibi activity was scored semiquantitatively in six left ventricular segments. Furthermore, sestamibi uptake was assessed quantitatively using a circumferential profile method. In 35 of 114 segments the score improved within 120 min p.i. (early fill-in); in these segments relative sestamibi activity rose from 69.9% +/- 22.5% to 74.5% +/- 20.8% (P < 0.01). In five patients this early fill-in was the only sign of exercise-induced hypoperfusion. In 7 of 114 segments the score deteriorated 120 min p.i. (early tracer washout); in these segments relative sestamibi activity declined from 85.6% +/- 9.9% to 80.1% +/- 10.7% (P < 0.02). In three of four patients with early tracer washout the corresponding coronary artery was significantly narrowed. In conclusion, a global myocardial sestamibi washout was registered within the first 120 min after injection. A fill-in of initial defects as well as an early tracer loss could be detected in a relevant number of patients with chronic coronary artery disease during the first 2 h p.i.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Circulation↗
PubMed1994

[Lung activity in 201Tl myocardial scintigraphy: distribution and correlation with hemodynamic parameters].

UNLABELLED: The aim of this study was 1. to investigate whether the pulmonary activity in 201Tl myocardial scintigraphy can be accurately quantified from the anterior SPECT projection, 2. to determine the pattern of the intrapulmonary Tl distribution, and 3. to assess the influence of parameters of left ventricular function on the lung/heart ratio (LHR). Scintigraphic images of 85 patients were analysed. In 24 patients planar anterior imaging of the thorax was performed in addition to myocardial SPECT, in 41 patients radionuclide ventriculography was performed within 4 weeks after Tl scintigraphy. IN CONCLUSION: 1. pulmonary Tl-content can be quantitated from the anterior SPECT projection with sufficient accuracy, 2. a lower thallium activity was registered over the apical part of the lung as compared to the basal part, and 3. in the multiple regression analysis the left ventricular ejection fraction (LVEF) during exercise and heart rate during exercise (HRex) exhibited the strongest relation to LHR. After correction with regard to HRex the elevated LHR points to a pathological LVEF during exercise.

Exercise Test↗
PubMed1992

[Brain scintigraphy (SPECT) with thallium-201 in primary brain tumors].

We evaluated the role of thallium-201 single-photon emission-computed tomography (SPECT) in diagnosis, differential diagnosis and follow-up of 33 patients with primary brain tumors. 27 of 33 lesions were detectable by Tl-201 SPECT because only two of eight low-grade (grade 1 and 2) astrocytomas showed Tl-201 accumulation up to a tumor to nontumor ratio of 2.6. High grade (grade 3 and 4) astrocytomas showed Tl-201 accumulation in the range of 2.2 up to 13.0 and were different from low-grade astrocytomas. Noninvasive grading of astrocytomas is therefore possible, whereas differential diagnosis of oligodendrogliomas and astrocytomas or meningiomas was not possible with Tl-201. In the follow-up of six patients, we could demonstrate, that tumor progression is correlated with increasing and tumor regression with decreasing Tl-201 accumulations. This functional changing proceed morphological findings in CT. But vanishing of Tl-201 accumulation during therapy does not mean vanishing of tumor as could be demonstrated by follow-up.

Adult↗
PubMed1989

Inhibitory effect of galanin on postprandial gastrointestinal motility and gut hormone release in humans.

Galanin was infused intravenously in 8 healthy volunteers at a dose of 40 pmol/kg.min for 1 h to investigate the pharmacologic effects of this peptide on postprandial gastrointestinal motility and gut peptide release in humans. Galanin strongly inhibited gastrointestinal motility. Gastric emptying was significantly delayed, with the time taken to empty 50% of the gastric contents increasing from 59.0 +/- 4.8 min (control infusion) to 99.3 +/- 4.7 min (galanin infusion). Mouth-to-cecum transit time increased from 67.5 +/- 6.9 to 126.3 +/- 18.5 min. Galanin potently suppressed the initial postprandial rise in plasma concentrations of glucose, insulin, peptide tyrosine tyrosine, neurotensin, enteroglucagon, pancreatic glucagon, somatostatin, and pancreatic polypeptide, but did not change gastric inhibitory polypeptide, motilin, peptide histidine methionine, and gastrin concentrations compared with control. The results indicate that an infusion of galanin has potent effects on the gastrointestinal tract in humans. The changes in motor activity in particular suggest that the local galaninergic innervation could have an important physiologic role in the control of human gastrointestinal propulsive motor activity.

Adult↗
PubMed1989

Diabetes-specific social learning variables and self-care behaviors among persons with type II diabetes.

This study assessed the relationship between diabetes-specific social learning factors and diabetes self-care. Predictor variables were collected within the categories of knowledge (e.g., behavioral demonstrations, pencil-and-paper tests), beliefs/expectations (e.g., self-efficacy, self-motivation), skills (e.g., problem-solving and refusal skills), and environmental support (e.g., barriers to adherence, family support). Different results emerged across the three areas of the regimen assessed: diet, exercise, and glucose testing. Multiple-regression analyses revealed that the social learning variables consistently improved the prediction of self-care beyond that attributable to demographic variables but that the categories of social learning variables most closely related to self-care varied across regimen areas. These findings suggest that programs to enhance diabetes self-care could beneficially focus on life-style behaviors and employ strategies to increase regimen-related expectations and diabetes-specific social and problem-solving skills.

Adult↗
PubMed1989

Nutrition education and social learning interventions for type II diabetes.

Two diabetes education programs were compared to a control condition. Seventy-eighty type II (non-insulin-dependent) diabetic outpatients were randomly assigned to nutrition education, nutrition education plus social learning intervention, or wait-list control conditions. Both interventions involved five weekly meetings that focused on reducing calorie intake, increasing dietary fiber, and decreasing fat consumption. The social learning condition also included individualized goal setting and feedback and training in problem-solving and relapse prevention. Within-group analyses and between-group comparisons generally revealed greater improvement in targeted goals (e.g., calorie intake, fat reduction) among intervention conditions than the control condition. There were few differences in more distal measures of outcome such as weight or glycosylated hemoglobin. The social learning component did not improve outcome more than the nutrition education program. Possible reasons for the observed findings and the advantages and limitations of focused time-limited diabetes education efforts are discussed.

Diabetes Mellitus, Type 1↗
PubMed1983

[Emission computed tomography of the left ventricle. Multiplanar ECG-triggered radionuclide ventriculography with a 7-pinhole collimator].

Tomographic studies and time-dependent tomograms on phantoms and patients were carried out using a 7-pinhole collimator in order to study the clinical value of ECG-triggered tomographic radionuclid ventriculography. A suitable computer programme has been developed. The results have shown that it is possible to evaluate local contraction abnormalities by this method. Using a left oblique position of the collimator (LAO [45 degrees]-cranial [15 degrees] ), emission computer tomography is aligned with the longitudinal axis of the heart. In this way, a single projection is sufficient to show the motility of the anterior and posterior walls and of the septum. Hypokinesis, akinesis or dyskinesis can be recognised visually. The localisation and extent of the defect can be determined through the 7-pinhole collimator. Reconstructed images of the triggered radionuclid scintigrams show excellent marginal definition. In the RAO projection, the left ventricle can be seen without superimposition and images obtained which equal those of a first-pass technique.

Cardiomyopathies↗
PubMed1980

The effect of etofibrate retard, bezafibrate and procetofen.

The effects and side effects of 500 mg of etofibrate retard were comared with those of 100 mg t.i.d. of procetofene and of 200 mg t.i.d. of bezafibrate in two different studies in 60 and 63 outpatients respectively. In types IIa, IIb and IV hyperlipoproteinaemia cholesterol, triglycerides, LDL-cholesterol and HDL-cholesterol were affected markedly stronger by procetofene and bezafibrate than by etofibrate retard. This impact was not only superior in its quantity by also in its proportion of responding patients. Side effects were a flush under etofibrate retard and gastric discomfort, headache and nausea in about 5% under all three drugs. Etofibrate retard did not give significant changes in the laboratory parameters while procetofene and bezafibrate slightly increased transaminases and creatinine. Alcaline phosphatase and GT were significantly lowered. Uric acid decreased under procetofene and increased under bezafibrate.

Aged↗