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Biomedical subjects

P Poon

Publications and source records attributed to P Poon.

11 recordsLinked to original sources
PubMed1995

Rapid measurement of somatosensory evoked potential response to cerebral artery occlusion.

The aim of the paper is to determine the speed of the neurological response to cerebral artery occlusion by monitoring transient changes in somatosensory evoked potentials (SEPs). SEPs, continuously monitored during temporary clipping of the middle cerebral artery (MCA) in anaesthetised cats, are analysed. The SEP signals are modelled by a quasi-periodic Fourier series, the coefficients of which are estimated with the aid of two adaptive least squares estimation algorithms. The energy levels at various harmonics throughout the protocol are obtained directly from the filter weights. Noise covariance is estimated from pre-stimulus recording, and the adaptation rate of the algorithm is adjusted sweep-by-sweep to accommodate transient changes in the pre-stimulus noise level. After the occlusion, a significant decrease (p < 0.05) in SEP amplitude is observed. The change in latency is not statistically significant (p approximately equal to 0.5). The spectral trends show a sudden decline in energy at all harmonics immediately following occlusion, although when the amplifier bandwidth is changed to 5-1500 Hz (from an initial setting of 30-1500 Hz), the fundamental frequency component of the SEP signal shows the greatest responsiveness to injury. The average time constant of the decline in amplitude resulting from MCA occlusion is only 10.6 +/- 4.0 s. It is concluded that rapid detection of cerebral artery occlusion and ischaemia may be feasible by continuously monitoring SEP signals and analysing transient changes in time and frequency domains.

Algorithms↗
PubMed1992

Prevalence of haemoglobin variants in a diabetic population and their effect on glycated haemoglobin measurement.

The measurement of glycated haemoglobin (glycated Hb) by automated high pressure liquid chromatography enabled the prevalence of haemoglobin variants (Hb variant) to be determined in a large diabetic population within Leeds, UK. There were 16 patients showing a Hb variant amongst a total of 5300 diabetics, the majority of the variants being HbA/S traits. There were also 13 patients showing a slightly raised HbF in the range of 2% to 5%. A multi-centre study was carried out by distributing blood specimens from some of the patients with Hb traits. Significant differences in the percentage of glycated Hb were observed relating to the methodology used. However, glycated Hb is used to monitor glycaemic control and laboratories must be aware of Hb variant interferences on their methods. Also, screening for Hb variants should be considered for the at risk groups of diabetic patients.

Diabetes Mellitus↗
PubMed1990

The use of alternative therapies by Auckland general practitioners.

A survey of Auckland general practitioners was undertaken to explore their use of, and attitudes to, alternative medicines. Three hundred and seventy randomly selected doctors, from a total of about 700 doctors practising in Auckland, were posted questionnaires. Of 249 respondents, 75 (30%) practised one or more forms of alternative medicine. Acupuncture was the therapy most commonly used. Musculoskeletal disorders and chronic pain syndromes were the most frequently treated conditions. A total of 171 (68.7%) respondents referred patients to one or more forms of alternative treatment, and only 56 (32.7%) of these felt it necessary that the person referred to be medically qualified. Younger doctors were more inclined to refer and the most commonly cited reason for referral was failure of conventional medicine.

Acupuncture Therapy↗
PubMed1983

Prevention of deterioration of renal and sensory-nerve function by more intensive management of insulin-dependent diabetic patients. A two-year randomised prospective study.

74 insulin-dependent diabetic patients with background retinopathy were randomised to continue with usual diabetic care (group U) or to a more intensive programme (group A) using ultralente insulin as basal cover and soluble insulin at mealtimes. Group A attended the clinic more frequently, received closer dietary supervision, and were taught home blood glucose monitoring. Group A had a significantly lower mean glycosylated haemoglobin level during the study, although the mean level also fell in group U towards the end of year 2. Renal and sensory-nerve function were significantly better preserved in group A than in group U. Significant improvements were also seen in low-density-lipoprotein-cholesterol and whole-blood low-shear viscosity. The rate of progression of retinopathy was similar in both groups. It appears that a modest improvement in diabetic control, obtainable in most clinics, has been associated with a reduction in the progression of diabetic tissue damage.

Blood Glucose↗