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Biomedical subjects

D R Murdoch

Publications and source records attributed to D R Murdoch.

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

Detection of Legionella DNA in peripheral leukocytes, serum, and urine from a patient with pneumonia caused by Legionella dumoffii.

The polymerase chain reaction (PCR) has been used to detect Legionella DNA in respiratory tract, serum, and urine samples from patients with pneumonia. In addition, a preliminary study using a guinea pig model suggested that testing of peripheral leukocytes by PCR may be more sensitive than testing of other samples. We used PCR to detect Legionella DNA in serial peripheral leukocyte (buffy coat), serum, and urine samples from a patient with pneumonia caused by Legionella dumoffii. Legionella DNA was detected in all 3 sample types when first collected. Buffy coat and urine samples remained positive up to 56 days after the onset of symptoms, whereas serum samples were positive from 10 up to 16 days after the onset of symptoms. Sequencing of PCR amplicons indicated the presence of L. dumoffii DNA in positive samples. It appears that buffy coat may be a useful sample to test for Legionella DNA, but further study is required to determine the precise sensitivity and to make comparisons with other sample types.

Aged↗
PubMed2000

Acute heart failure: a practical guide to management.

Acute heart failure is a common cause of referral and admission to hospital. It requires prompt recognition and treatment. This article will address the practical issues regarding diagnosis, investigation, treatment and prevention of recurrence.

Acute Disease↗
PubMed2000

Female genital schistosomiasis.

Schistosoma haemtobium infection in travelers from endemic areas is usually asymptomatic, or presents with hematuria. Uncommon manifestations include neurological syndromes, genital dysaesthesias and watery or blood stained semen. This organism also causes disease within all structures of the female genital tract because of communications between pelvic venous complexes, and can occur long after return home. Schistosomiasis may not be suspected, resulting in delays in diagnosis and treatment. We present two cases which illustrate the diverse nature of this condition.

Adult↗
PubMed1999

Persistence of iodine deficiency 25 years after initial correction efforts in the Khumbu region of Nepal.

AIMS: To assess the current status of, and understanding about iodine deficiency disorders among Sherpa residents of the Khumbu region of Nepal, 25 years after the introduction of iodised oil injections. METHODS: Several groups of Khumbu Sherpas were studied and goitre rate, urinary iodine level and cretinism prevalence were measured as indicators of iodine deficiency. Subjects were also questioned in detail about their food consumption, with particular reference to salt use, and about their understanding of the causes and treatment of iodine deficiency disorders. RESULTS: The prevalences of goitre, deaf-mutism and cretinism were 21%, 1.3% and 0.5% respectively (compared to 92%, 4.7% and 5.9% in 1966). No cretins had been born since 1966. The median urine iodine concentration was 35 microg/L. Most people preferred uniodised Tibetan rock salt, although 44% regularly consumed iodised salt. All granulated salt tested from the local market contained adequate amounts of iodine. Only 11% of those surveyed knew that goitre was caused by iodine deficiency CONCLUSIONS: Although prevalences of iodine deficiency disorders are much less than 30 years ago, iodine deficiency continues to be a major problem in Khumbu and demands a clear control strategy, combining ongoing iodine supplementation and education. Iodised salt is usually the best approach to control of iodine deficiency disorders for most regions of the world but the Khumbu experience shows that local cultural and commercial factors can severely limit its impact. To be successful, control programme for iodine deficiency disorders also needs assessment of the salt trade, monitoring, education and occasional targeted interventions with iodised oil or other supplements.

Adolescent↗
PubMed1999

Legionella, Chlamydia pneumoniae and Mycoplasma infection in patients admitted to Christchurch Hospital with pneumonia.

AIMS: To determine the incidence, clinical features and outcome of community acquired pneumonia caused by Mycoplasma pneumoniae, Legionella species, Coxiella burnetti, Chlamydia pneumoniae and Chlamydia psittaci requiring admission to hospital. METHODS: Over 12 months the clinical findings and severity of pneumonia were recorded prospectively. Sputum, blood, serum and urine samples were collected for diagnostic testing. Management was supervised by the admitting medical team. Subjects were followed-up six weeks after discharge. RESULTS: Two hundred and fifty-five patients met the entry criteria of whom 20 died, including five who had Legionella infection. M pneumoniae (16%) infection was more often of mild/moderate severity (95%), occurred in a younger age group (mean age 31.4 years, p=0.002), with more frequent myalgia and headache. The length of hospital stay was shorter and clearing of chest radiograph and return to normal activity occurred more rapidly in this group of patients. Legionellosis was common as judged by culture and serological testing (26 cases, 11%) and a further 22 cases were identified by polymerase chain reaction. Legionella infection was not distinguishable clinically from other pneumonias. C pneumoniae was uncommon (8 cases, 3%). C burnetti and C psittaci were not identified in this study. CONCLUSIONS: Some cases of pneumonia caused by Mycoplasma pneumoniae can be identified at presentation, however pneumonia due to Legionella is not distinguishable on clinical grounds. Development of molecular diagnostic techniques may enable therapy to be directed against specific organisms earlier in the course of the disease.

Adolescent↗
PubMed1999

Detection of Legionella DNA in guinea pig peripheral leukocytes, urine and plasma by the polymerase chain reaction.

Legionella DNA has been detected in respiratory tract, serum and urine samples from patients with pneumonia by the polymerase chain reaction. A guinea pig model was used to assess whether Legionella DNA could also be detected in peripheral leukocytes during active infection. Ten guinea pigs were infected intraperitoneally with Legionella pneumophila serogroup 1, and leukocyte, plasma and urine samples were collected immediately before inoculation and on days 1, 3, 7 and 14 thereafter. All samples were tested for Legionella DNA by the polymerase chain reaction. Overall, Legionella DNA was detected in 55% of leukocyte samples, 28% of urine samples and 21% of plasma samples collected after inoculation. The sensitivity of the polymerase chain reaction on leukocytes was highest for samples collected within 3 days of inoculation. Further studies testing leukocyte samples from human Legionella infection are required to confirm these observations.

Animals↗
PubMed1999

Titration of vasodilator therapy in chronic heart failure according to plasma brain natriuretic peptide concentration: randomized comparison of the hemodynamic and neuroendocrine effects of tailored versus empirical therapy.

BACKGROUND: Most patients with chronic heart failure (CHF) receive the same dose of angiotensin-converting enzyme (ACE) inhibitors because there is currently no measure of treatment efficacy. We sought to determine whether titration of vasodilator therapy according to plasma brain natriuretic peptide (BNP) concentration may be of value in the individual optimization of vasodilator therapy in CHF. METHODS AND RESULTS: Twenty patients with mild to moderate CHF receiving stable conventional therapy including an ACE inhibitor were randomly assigned to titration of ACE inhibitor dosage according to serial measurement of plasma BNP concentration (BNP group) or optimal empirical ACE inhibitor therapy (clinical group) for 8 weeks. Only the BNP-driven approach was associated with significant reductions in plasma BNP concentration throughout the duration of the study and a significantly greater suppression when compared with empiric therapy after 4 weeks [-42.1% (-58.2, -19.7) vs -12.0% (-31.8, 13.8), P =.03]. Both treatment strategies were well tolerated and associated with favorable neurohormonal and hemodynamic effects; however, in comparison between groups, mean heart rate fell (P =.02) and plasma renin activity rose (P =.03) in the BNP group when compared with the clinical group. CONCLUSIONS: Plasma BNP concentration may be chronically reduced by tailored vasodilator therapy in CHF. Furthermore, titration of vasodilator therapy according to plasma BNP was associated with more profound inhibition of the renin-angiotensin-aldosterone system and significant fall in heart rate when compared with empiric therapy.

Aged↗
PubMed1999

The pre-operative ECG in day surgery: a habit?

As the population presenting for day-case surgery and anaesthesia increases, so does the challenge of adequate pre-operative assessment. Although an electrocardiogram is frequently performed, its value in day-case surgery remains unproven. One thousand, one hundred and eighty-five patients presenting for day-case surgery were assessed. One hundred and fifty-four (13%) were referred for electrocardiogram according to well-recognised criteria for the prediction of coronary artery disease. They were read independently by the anaesthetist responsible for the case and by an experienced cardiologist. A significant abnormality was noted in 26% of electrocardiograms, most frequently in patients referred with hypertension. There was a good correlation between the reports of the anaesthetist and cardiologist. Only 20% of those patients with an abnormal electrocardiogram had their surgery postponed. No adverse events occurred in patients proceeding to surgery despite the abnormalities. We conclude that a resting electrocardiogram is of limited value in risk stratification of patients undergoing day-case surgery.

Adult↗
PubMed1999

Inappropriately low plasma leptin concentration in the cachexia associated with chronic heart failure.

BACKGROUND: Cardiac cachexia is a syndrome of generalised wasting which caries a poor prognosis and is associated with raised plasma concentrations of tumour necrosis factor alpha (TNFalpha). TNFalpha increases secretion of leptin, a hormone which decreases food intake and increases energy expenditure. OBJECTIVE: To determine whether an inappropriate increase in plasma leptin concentration contributes to the cachexia of chronic heart failure. DESIGN: Retrospective case-control study. SETTING: Tertiary referral cardiology unit. PATIENTS: 110 human subjects comprising 29 cachectic chronic heart failure patients, 22 non-cachectic chronic heart failure patients, 33 patients with ischaemic heart disease but normal ventricular function, and 26 healthy controls. INTERVENTIONS: Measurement of: body fat content by skinfold thickness (cachectic males < 27%, females < 29%); plasma leptin, TNFalpha, and noradrenaline (norepinephrine); central haemodynamics in chronic heart failure patients at right heart catheterisation. MAIN OUTCOME MEASURES: Plasma leptin concentration corrected for body fat content, plasma TNFalpha and noradrenaline concentration, and central haemodynamics. RESULTS: Mean (SEM) plasma leptin concentrations were: 6.2 (0.6) ng/ml (cachectic heart failure), 16.9 (3.6) ng/ml (non-cachectic heart failure), 16.8 (3.0) ng/ml (ischaemic heart disease), and 18.3 (3.5) ng/ml (control) (p < 0.001 for cachectic heart failure v all other groups). Plasma leptin concentration remained significantly lower in the cachectic heart failure group even after correcting for body fat content and in spite of significantly increased TNFalpha concentrations. Thus plasma leptin was inappropriately low in cachectic chronic heart failure in the face of a recognised stimulus to its secretion. There was no significant correlation between plasma leptin, New York Heart Association class, ejection fraction, or any haemodynamic indices. CONCLUSIONS: Leptin does not contribute to the cachexia of chronic heart failure. One or more leptin suppressing mechanisms may operate in this syndrome-for example, the sympathetic nervous system.

Adipose Tissue↗
PubMed1998

Acute mountain sickness in the Southern Alps of New Zealand.

AIM: To assess the incidence and impact of acute mountain sickness in the Southern Alps of New Zealand. METHODS: Over a 22 month period, mountaineers in the Mount Cook region were asked to complete a questionnaire at the completion of their climbing excursions. The questionnaire recorded demographic data and incorporated the Lake Louise scoring system to assess the presence of acute mountain sickness. RESULTS: Of the 114 subjects who completed the questionnaire, 30 (26%) developed acute mountain sickness. The incidence was higher amongst those who slept above 2500 m (50%). Of those with acute mountain sickness, 33% reported that their symptoms resulted in no reduction in activity, while 13% reported a moderate or severe reduction in activity. CONCLUSION: Mountaineers climbing in New Zealand's Southern Alps should be aware of the risk of acute mountain sickness, especially for those sleeping above 2500 m.

Adolescent↗
PubMed1998

Biochemical detection of left-ventricular systolic dysfunction.

BACKGROUND: In previous studies on the use of natriuretic peptides to detect left-ventricular systolic dysfunction, a higher rate of cardiac disorders in the control groups than in the study groups could have led to bias. We investigated the effectiveness of plasma N-terminal atrial natriuretic peptide (NT-ANP) and brain natriuretic peptide (BNP) concentrations to show left-ventricular systolic dysfunction in a random sample of the general population. METHODS: We randomly selected 2000 participants aged 25-74 years from family physicians' lists in Glasgow, UK. We sent all participants questionnaires. 1653 respondents underwent echocardiography and electrocardiography. We took a left-ventricular ejection fraction of 30% or less to show left-ventricular systolic dysfunction. NT-ANP and BNP were measured in plasma by RIAs. FINDINGS: 1252 participants had analysable electrocardiograms and echocardiograms, completed questionnaires, and available blood samples. Median concentrations of NT-ANP and BNP were significantly higher in participants with left-ventricular systolic dysfunction (2.8 ng/mL [IQR 1.8-4.6] and 24.0 pg/mL [18.0-33.0]) than in those without (1.3 ng/mL [0.9-1.8] and 7.7 pg/mL [3.4-13.0]; each p < 0.001). Among participants with left-ventricular systolic dysfunction, both symptomatic and asymptomatic subgroups had raised NT-ANP and BNP concentrations. A BNP concentration of 17.9 pg/mL or more gave a sensitivity of 77% and specificity of 87% in all participants, and 92% and 72% in participants aged 55 years or older. INTERPRETATION: Measurement of BNP could be a cost-effective method of screening for left-ventricular systolic dysfunction in the general population, especially if its use were targeted to individuals at high risk.

Adult↗