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Biomedical subjects

D Thomson

Publications and source records attributed to D Thomson.

At least 37 records · Page 2Linked to original sources
PubMed1996

Right ventricular nerve sheath tumour and patent foramen ovale presenting with transient ischemic attack.

A 66-year-old man presented with dyspnea and a transient ischemic attack. Echocardiography revealed a right ventricular mass and patent foramen ovale. During surgery the mass was found to be a malignant nerve sheath tumour. Several weeks later, the patient developed small bowel obstruction, and laparotomy disclosed multiple metastases involving the small and large bowel. The paper describes the clinical course and management of this patient and reviews the pertinent literature.

Aged↗
PubMed1995

Psychological responses to malignant melanoma. An investigation of traumatic stress reactions to life-threatening illness.

A cross-sectional study of 95 individuals with malignant melanoma was conducted to investigate posttraumatic stress responses to a diagnosis of melanoma and to validate the use of the Impact of Event Scale (IES) as a measure of the response to the trauma of life-threatening disease. The diagnosis and progression of malignant disease are likely to present a range of acute and chronic trauma to the individual and the individual's family. The findings suggest that the IES is a reliable and valid measure of this distress, with scores varying according to disease progression and prognostic status of nonmetastatic disease patients. This indicates the importance of clinical attention to the specific symptoms that may best reflect the traumatic impact of life-threatening illness and its progression, and the applicability of posttraumatic stress syndromes in understanding the psychological distress of this clinical population.

Adult↗
PubMed1995

Detection of DNA and RNA plant viruses by PCR and RT-PCR using a rapid virus release protocol without tissue homogenization.

A simple, single-step plant tissue preparation protocol suitable for the detection of viruses by the polymerase chain reaction and reverse transcription-polymerase chain reaction is described. The effect of buffer components and pH, and the incubation temperature for the release of virus from plant material was evaluated. A small amount of plant tissue was heated in a solution containing 100 mM Tris-HCl, pH 7.4 or 8.4, 1 M KCl and 10 mM EDTA for 10 min at 95 degrees C and the supernatant used for enzymatic amplification. This protocol was suitable for the detection of both DNA and RNA viruses in a variety of plant species and tissues and reduced plant inhibitory factors which may interfere with PCR. The application of this method was demonstrated for the detection of banana bunchy top virus in banana leaves, root and corn, zucchini yellow mosaic potyvirus in squash leaves and lettuce necrotic yellows rhabdovirus in lettuce and Nicotiana glutinosa leaves.

Base Sequence↗
PubMed1995

Death in notified cases of tuberculosis in Edinburgh: 1983-1992.

Between 1983-1992, 730 cases of tuberculosis were notified in the Edinburgh area (population 6 x 10(5)). A review of available records identified 79 deaths (10.9% of all notifications). Thirty-seven patients (5.1%) died in the year following notification, 14 of these (five females, nine males; median age 71 years) due to tuberculosis. Five of these 14 deaths occurred within 7 days of starting chemotherapy and three deaths were due to miliary disease. Of 41 deaths (58%) before notification, 29 (19 females, 10 males; median age 77 years) were due to tuberculosis (autopsy rate 27/29) and 13 of these 29 deaths, all autopsied, were due to cryptic miliary disease. These findings reinforce continuing concerns about failure to diagnose tuberculosis, particularly cryptic miliary disease, in life.

Adult↗
PubMed1995

Postoperative physical therapy after coronary artery bypass surgery.

Coronary artery bypass surgery is frequently complicated by postoperative atelectasis. Although routinely prescribed, the efficacy of any specific chest physical therapy is not well established. We studied patients at a university center undergoing elective coronary artery bypass surgery. Based upon chest X-ray criteria at extubation, patients (n = 228) were classified as demonstrating greater or lesser degrees of atelectasis. Those with a lesser degree of atelectasis were randomized to receive either early mobilization or sustained maximal inflations (SMI). Those with greater a degree of atelectasis were separately randomized to receive either SMI or single-handed percussions (SSP). We found the extent of atelectasis at extubation did not predict the risk of developing pneumonia. Hospital stays and intensive care unit stays were similar regardless of treatment. Physical therapy costs were highest in the most labor-intensive therapy group (SSP). We conclude that postoperative respiratory dysfunction is common but does not commonly cause significant morbidity or prolong hospital stay. Adding SMI to patients with minimal atelectasis at extubation does not improve clinical outcomes. Similarly, adding SSP to patients with marked atelectasis does not improve outcomes over those obtained with SMI and early ambulation.

Aged↗
PubMed1995

Depletion of neutrophils by filter during aortocoronary bypass surgery transiently improves postoperative cardiorespiratory status.

STUDY OBJECTIVE: To determine whether inclusion of a leukocyte specific filter into the extracorporeal circuit during aortocoronary bypass surgery alters postoperative cardiopulmonary function. DESIGN: Randomized, double-blinded control trial. SETTING: Tertiary care hospital. PATIENTS: Convenience sampling of patients undergoing elective aortocoronary bypass between October 1992 and June 1993. INTERVENTIONS: A total of 32 patients were randomized to a leukocyte specific filter (n = 16) or to a standard blood filter (n = 16) during the surgical procedure. MEASUREMENTS AND RESULTS: White blood cell count in the standard filter group (12.2 +/- 3.6 10(9)/L) was higher (p = 0.047) than in the leukocyte filter group (9.9 +/- 2.6 10(9)/L) at 4 h postoperatively but counts were similar (p = 0.063) at 24 h (10.8 +/- 2.7 vs 8.9 +/- 2.6 10(9)/L, respectively). Leukocyte activation assessed by chemiluminescence was similar between groups at all measurement periods. We noted transient improvements (p < 0.05) in intrapulmonary shunt (19 +/- 50% vs 24 +/- 9%) and mean blood pressure (85 +/- 8 vs 76 +/- 9 mm Hg, respectively) in the leukocyte filter group compared with the standard filter group, respectively. Otherwise there were no differences noted between groups. CONCLUSIONS: Inclusion of a leukocyte filter during cardiopulmonary bypass caused transient cardiorespiratory improvement that was lost within 24 h and did not offer any significant clinical benefits.

Aged↗
PubMed1995

Single-step protocol for preparation of plant tissue for analysis by PCR.

PCR has many applications in the isolation and analysis of plant DNA. The influence of salt and EDTA concentration, pH, incubation time and temperature on the preparation of plant material for PCR was evaluated. A general single-step method was developed in which a small amount of plant tissue was heated in a simple solution. The DNA in the supernatant was found to be suitable for most PCR applications including arbitrarily primed PCR (random-amplified polymorphic DNA) and PCR with specific primers for both single- and multiple-copy genes. The technique is much simpler than those generally used for plant DNA preparation and was successful with tissues from a wide range of species.

Base Sequence↗
PubMed1994

Preoptic/anterior hypothalamic warming increases EEG delta frequency activity within non-rapid eye movement sleep.

The effects of mild POAH warming and cooling on EEG frequency patterns within sustained periods of NREM sleep were examined. EEG spectral power analysis showed that POAH warming increased delta (0.5-4.0 Hz) activity, but had no effect on theta or sigma frequencies. Delta power was also increased during a 1 h recovery period, following warming. POAH cooling had no EEG effects. Since delta power is thought to be an index of sleep depth, our findings suggest that POAH thermoregulatory mechanisms participate in the regulation of the depth of NREM sleep.

Animals↗
PubMed1994

Expression of tissue kallikrein in human kidney.

1. We studied the distribution of human tissue kallikrein mRNA in normal and diseased kidney, using in situ hybridization, together with immunohistochemical localization of renal kallikrein protein. Materials studied were (a) normal tissue from kidneys removed because of localized renal carcinoma, (b) kidneys removed because of post-traumatic haemorrhage and (c) renal biopsy specimens from patients with membranous glomerulonephritis and nephrotic syndrome. 2. A 1.35 kb EcoRI fragment of human tissue kallikrein cDNA was labelled with [32P]dCTP using the random-primer technique, and used for in situ hybridization. A specific rabbit antibody to active human urinary kallikrein was employed for immunocytochemistry, using a peroxidase-antiperoxidase method. 3. By in situ hybridization, no tissue kallikrein gene expression was seen in the carcinoma nephrectomy specimens. Positive expression was seen in the trauma nephrectomy tissue, and in four of five nephrotic syndrome biopsies. In all kidneys, expression was confined to the renal cortex. The dominant site of gene expression was the distal tubule. Apart from one area of positive signal related to an epithelial cell of Bowman's capsule, expression was not observed in glomeruli. Expression was also seen in the walls of large- and medium-sized blood vessels. 4. By immunohistochemistry, the dominant site of immunoreactivity was the distal tubule. Dense staining was also seen in granular peripolar cells and in isolated parietal epithelial cells close to the vascular pole. Isolated immunoreactive cells were seen in the media of large- and medium-sized arteries. 5. The tissue kallikrein gene in the kidney may not be constitutively expressed, but is expressed in response to physiological or pathological stimuli.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Repeated episodes of myocardial ischaemia during combined thoracic epidural-isoflurane anaesthesia.

A patient with a history of coronary artery diseases developed new ST segment depressions in the ECG registration during a low dose (0.7%) isoflurane anaesthesia that was combined with a continuous thoracic epidural analgesia. Simultaneously a small decrease in mean arterial blood pressure (MAP) was noted. During the next 5 min these changes were followed by a severe drop in MAP (from 88 to 60 mmHg) and in cardiac output from 5.5 to 3.2 L/min. When isoflurane was discontinued both the ECG and the cardiovascular changes returned to the previous condition. Later, when 0.5% isoflurane was restarted, the ECG changes reappeared within ten min, but disappeared once again when isoflurane administration was discontinued. Thus, this patient had repeated episodes of myocardial ischaemia which were associated with the use of low dose isoflurane. Although isoflurane-induced "coronary steal" may appear as a likely cause of these ischaemic episodes, it is possible that the thoracic epidural had synergistic action and rendered the patient exceptionally sensitive to minor changes in perfusion pressure.

Anesthesia, Epidural↗
PubMed1994

Neutrophil-mediated acute lung injury after extracorporeal perfusion.

A pulmonary injury of varying severity occurs routinely after cardiopulmonary bypass. We studied the pulmonary complications of partial cardiopulmonary bypass in four groups of dogs to better define the injury and to evaluate the efficacy of two interventions (addition of a leukocyte filter or cyclooxygenase inhibition) on preservation of systemic oxygenation. All animals received a standard anesthetic (pentobarbital, morphine, and vecuronium) and, after sternotomy, three groups of animals received 3 hours of partial cardiopulmonary bypass. The animals were randomized to receive partial bypass alone (n = 6), indomethacin and bypass (n = 5), or a leukocyte filter and bypass (n = 5). A fourth group (n = 5) did not receive bypass and served as a time control. We measured blood gases and also obtained histologic samples to assess the degree of lung injury. We found that bypass alone caused a significant reduction (p < 0.05) in arterial oxygen tension 1 hour after the conclusion of bypass (175 +/- 53 mm Hg) compared with prebypass values (357 +/- 41 mm Hg). Pretreatment with indomethacin ameliorated the decrease in arterial oxygen tension from prebypass to postbypass values (477 +/- 50 mm Hg versus 339 +/- 57 mm Hg, respectively). Similarly use of a leukocyte filter reduced the decline in arterial oxygen tension from prebypass to postbypass values (440 +/- 71 mm Hg versus 311 +/- 73 mm Hg, respectively). We believe that indomethacin ameliorates the decline in systemic oxygenation associated with bypass by augmentation of hypoxic pulmonary vasoconstriction and that the leukocyte filter acted to reduce pulmonary edema and thereby minimized intrapulmonary shunt.

Animals↗
PubMed1993

Analysis of the anti-p53 antibody response in cancer patients.

Mutations in the p53 tumor suppressor gene giving rise to mutant p53 proteins are among the most common genetic alterations associated with tumor cells. Mutant p53 gene products lose the wild type ability to suppress transformation in vitro or regulate cellular gene transcription. Mutant and wild type p53 protein conformations differ and mutant p53 is often present at high levels in the tumor cell relative to the low levels found in normal cells. Despite the major advances made to characterize the structure and biology of mutant and wild type p53, the humoral immune response against mutant p53s remains to be clearly defined. In the present study we have examined the anti-p53 response from cancer patients against the native and denatured state of mutant and wild type p53. Western blot analysis, immunoprecipitation analysis, and dilution analysis demonstrate that the anti-p53 sera recognize both wild type and mutant p53 conformational and denaturation resistant epitopes. There was no evidence that the mutant p53 molecules contain dominant antigenic epitopes which are not present on the wild type p53 protein. We also demonstrate that patients with ovarian cancer are also among those which can produce anti-p53 antibodies.

Antibodies, Neoplasm↗
PubMed1993

Selective increases in non-rapid eye movement sleep following whole body heating in rats.

Afternoon body heating has been reported to increase amounts of slow wave sleep (SWS) during the subsequent night in humans. This delayed effect of body heating on SWS has not been previously studied in laboratory animals. We examined the effect of whole body heating during the last 4 h of the light period on sleep and brain temperature (Tbr) during the subsequent twelve hour period in rats. Whole body heating was accomplished by elevating ambient temperature, typically to 33-35 degrees C, which increased Tbr to 40 +/- 0.5 degrees C. This condition was compared to a sleep-matched control condition, a sleep-deprived control condition and to a baseline condition. Following heating, non-rapid eye movement sleep 2 (NREMS2 or deep NREMS) was significantly increased during the first 2 h of the recovery period compared with baseline and sleep-matched control conditions and during the first hour compared with the totally sleep-deprived condition. NREMS1 was not significantly changed by heating. Rapid eye movement sleep was not different following heating compared to the sleep-matched and sleep-deprived control conditions but was significantly increased during the first hour of the recovery period following heating compared to baseline. Tbr was significantly lower for the first 5 h and the 7th h following heating compared to all three other conditions. Possible relationships between the regulation of sleep and temperature are discussed.

Animals↗
PubMed1993

Neurotoxicity of peptide analogues of the transactivating protein tat from Maedi-Visna virus and human immunodeficiency virus.

Infection by lentiviruses such as human immunodeficiency virus, Maedi-Visna virus and Caprine Arthritis Encephalitis Virus, is associated with a variety of neurological syndromes, but the mechanism by which the damage occurs to the nervous system is not known. The viruses do not infect neurons and so the neurotoxic actions must be mediated indirectly. Here we applied synthetic peptide analogues derived from basic regions of Maedi-Visna virus and human immunodeficiency virus transactivating protein, tat, to rat brain in vivo and found them to be potent neurotoxins. The toxicity of the Maedi-Visna virus peptide was demonstrated to be reduced by blockade of nitric oxide synthase and of N-methyl-D-aspartate channel opening. These experiments suggest that peptides derived from lentiviral tat may share a common neurotoxic action.

Amino Acid Oxidoreductases↗
PubMed1993

Prognostic value of quality of life scores in a trial of chemotherapy with or without interferon in patients with metastatic malignant melanoma.

In a multi-centre randomised clinical trial comparing dacarbazine (DTIC) plus recombinant interferon-alfa2a (IFN) versus DTIC alone for patients with metastatic malignant melanoma, aspects of quality of life (QL) were measured prospectively by patients using linear analogue self assessment (LASA) scales including the GLQ-8 and by doctors using Spitzer's QL Index. QL scores and performance status at the time of randomisation were available for 152 of 170 eligible patients. These scores carried significant prognostic information. In univariate analyses, Spitzer QL Index assessed by the doctor and LASA scores for physical wellbeing (PWB), mood, pain, appetite, nausea and vomiting, GLQ-8 total and overall QL were significant (P < 0.01) predictors of subsequent survival. QL Index and LASA scales for mood, appetite, and overall QL remained independently significant (all P < 0.05) in multivariate models allowing for significant prognostic factors other than QL (liver metastases and performance status). These findings closely parallel those in patients with metastatic breast cancer. They add further validity to the QL Index and LASA scores, provide the first evidence of the prognostic significance of the GLQ-8, and argue strongly for the routine assessment of QL in future therapy trials.

Adult↗