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Biomedical subjects

D M Levy

Publications and source records attributed to D M Levy.

At least 55 records · Page 3Linked to original sources
PubMed1991

Changes in cholinergic sweat gland activation in diabetic neuropathy identified by computerised sweatspot analysis.

Peripheral small-fibre denervation has been reported to result in decreased activation of eccrine sweat glands to muscarinic cholinergic agents. Using computerised image-analysis of pilocarpine-activated sweatspot prints of a 4 cm2 area of the dorsum of the foot in 79 randomly selected diabetic patients we have identified a group of neuropathic patients (18%) with decreased sweatspot activation (less than 20/cm2), and a smaller group (6%) of younger patients with less marked neuropathy who had increased activation (greater than 132/cm2), probably resulting from denervation supersensitivity. The associations between sweatspot density and other conventional tests of peripheral nerve function were weak. The prevalence of abnormal sweatspot density, 24%, was similar to that of other tests, except thermal thresholds at the feet (35-37%), which were not correlated with sweatspot activation, suggesting that diabetic neuropathy has differing effects on afferent and efferent small fibres. The method is rapid and reproducible (median coefficient of variation 14%) and its ability to identify patients with increased, as well as decreased, peripheral nerve function may be of value in the characterisation and longitudinal follow-up of small-fibre abnormalities in diabetes.

Adult↗
PubMed1991

Assessment of basal and stimulated sweating in diabetes using a direct-reading computerized sudorometer.

Abnormalities of eccrine sweating are thought to be common in diabetes. We describe a ventilated-capsule sudorometer for the continuous measurement of basal and stimulated sweat secretion. It is sensitive (detecting as little as 200 ng water vapour), precise, and stable. Since it measures dewpoint rather than relative humidity, it can be calibrated to read sweat volumes directly and independently of ambient temperature and humidity. Preliminary studies using this technique show that basal skin water loss is significantly diminished in patients with established diabetic neuropathy (0.91 +/- 0.18 g (+/- SD) cm-2 h-1) compared with normal subjects (1.21 +/- 0.39 g cm-2 h-1; p = 0.04) and non-neuropathic diabetic subjects (1.32 +/- 0.48 g cm-2 h-1; p = 0.04), and that local sweating induced by iontophoresis of 10 g l-1 acetylcholine is significantly reduced in diabetic subjects up to 5 min of recording (0.95 +/- 0.43 vs 1.26 +/- 0.40 mg; p = 0.02). In neuropathic subjects both low- and high-amplitude responses are seen, the latter probably representing denervation supersensitivity. Further studies with sensitive sudorometry should enable the mechanisms of these abnormal responses to be established.

Acetylcholine↗
PubMed1989

Depletion of cutaneous nerves and neuropeptides in diabetes mellitus: an immunocytochemical study.

Immunocytochemistry for the general neuronal marker protein gene product 9.5 and four neuropeptides (calcitonin gene-related peptide, substance P, vasoactive intestinal polypeptide and neuropeptide Y) was performed on 20 skin biopsy specimens from 19 diabetic patients, age range 20-75 years, 17 Type 2 (non-insulin-dependent) and 3 Type 1 (insulin-dependent). Fifteen specimens were from the lower limb, 3 from the upper limb and 2 from the abdominal wall. Seven subjects had lower limb neurophysiological tests. All but one specimen showed reduced protein gene product 9.5 and neuropeptide immunoreactivity. Reduced protein gene product 9.5 and neuropeptide immunoreactivity was found in specimens taken from the abdominal wall and hand as well as those from the leg, and also in specimens from patients undergoing amputation for peripheral vascular disease. In general, the greater the number of abnormal neurophysiological tests, the greater the extent of neuronal abnormalities. Three patients with normal tests had abnormalities of dermal innervation. While these changes are also found in other axonal neuropathies, in the absence of other causes of peripheral nerve disease and of macrovascular disease, immunocytochemistry of skin biopsies may have a role in the assessment of diabetic neuropathy and its response to treatment.

Adult↗
PubMed1988

Pelvic floor neuropathy: a comparative study of diabetes mellitus and idiopathic faecal incontinence.

Twenty one patients with diabetic peripheral neuropathy, 18 with idiopathic faecal incontinence and 11 normal controls were studied with techniques of mucosal electrosensitivity, rectal distension for the quantitative assessment of anorectal sensation, and manometric and electromyographic tests for the assessment of anorectal motor function. An asymptomatic sensorimotor deficit was found in the anal canal of patients with diabetic peripheral neuropathy. Mucosal electrosensitivity thresholds in the anal canal were significantly higher (p less than 0.01 v controls) and fibre density of the external anal sphincter significantly raised (p less than 0.0001 v controls). Anal manometry and pudendal nerve terminal motor latencies were similar to controls. In patients with idiopathic faecal incontinence the tests of sensory and motor function also showed a sensorimotor neuropathy; compared with controls, mucosal electrosensitivity thresholds were significantly higher (p less than 0.002), anal canal resting and maximum squeeze pressures were significantly lower (p less than 0.05 and p less than 0.002 respectively), and pudendal nerve terminal motor latencies and fibre density of the external anal sphincter were significantly raised (both p less than 0.05). Sensory thresholds to rectal distension were similar in all groups. Pelvic floor sensorimotor neuropathy in diabetic patients has several features in common with that of patients with idiopathic faecal incontinence but its functional significance remains uncertain.

Adult↗
PubMed1988

Changes in thermal sensation in diabetic patients after treatment with gangliosides.

Thirty diabetic patients (mean age (+/- SD) 45.7 +/- 11.4 years, mean duration of diabetes 7.5 +/- 7.0 years, 17 insulin-dependent), were given 3 months of placebo injections followed by either 3-4 or 6 months injections of 100 mg mixed gangliosides (Cronassial) every weekday intramuscularly in a double-blind placebo-controlled study. There was an improvement of 0.77 +/- 1.25(10) degrees C and 0.65 +/- 1.05(10) degrees C in the thermal thresholds of the Cronassial treated group after 13-19 weeks and greater than 20 weeks respectively (p less than 0.22 from change of 0.04 +/- 0.59 degrees C in group treated with placebo. Compared to those with normal thresholds, patients with abnormal thermal thresholds (greater than 1.2 degrees C) improved significantly after Cronassial treatment for 13-19 weeks (-1.13 +/- 1.72(12) vs. 0.03 +/- 0.45(16) degrees C, p less than 0.006) and for greater than 20 weeks (-1.83 +/- 1.46(6) vs. 0.06 +/- 0.59(11), p less than 0.004) but this may have been related to the fact that the degree of improvement in thermal sensation was correlated with the initial thermal threshold (r = -0.80(28), p less than 0.001). There were no significant changes in electrophysiological measurements or vibration thresholds. Gangliosides are known to increase nerve sprouting and dendritogenesis and their effects in diabetic patients may be more easily seen using tests of small fibre function.

Action Potentials↗
PubMed1984

Herpes simplex type 2 meningitis treated with acyclovir.

A case of meningitis due to a primary genital herpes simplex type 2 infection, and its prompt response to therapy with intravenous acyclovir is reported. This complication of genital herpes is probably underdiagnosed and it is worthwhile searching for evidence of genital herpetic lesions in a young patient presenting with viral meningitis.

Acyclovir↗
PubMed1980

Inhibition of adrenergic neurotransmission in ischaemic regions of the canine left ventricle.

To test hypothesis that adrenergic neurotransmission is impaired in acute myocardial ischaemia, we studied contractile function of normal and ischaemic myocardium after coronary artery occlusion. For each area we compared the contractile response to left sympathetic nerve stimulation (LSS) with the response to exogenous noradrenaline (NA). Contractile response was measured with intramyocardial sonomicrometers. LSS increased aortic pressure and heart rate. NA was infused to achieve an aortic pressure equivalent to LSS and simultaneous atrial pacing matched the heart rate during LSS. In normal zones both interventions produced increased shortening equivalently. In ischaemic zones systolic expansion was unchanged during LSS, while NA improved contractile function of the same zones by decreasing systolic expansion. These responses occurred during ischaemia produced by either anterior or posterior descending coronary occlusion. Changes in regional blood flow, measured by 8 microns radiolabelled microspheres, could not account for the difference between the ischaemic regional response to LSS or NA. We conclude that acute regional ischaemia impairs adrenergic nerve transmission.

Adrenergic Fibers↗