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Biomedical subjects

J Pollard

Publications and source records attributed to J Pollard.

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

Inflammatory infiltrates in sural nerve biopsies in Guillain-Barre syndrome and chronic inflammatory demyelinating neuropathy.

Prompted by observations in experimental autoimmune neuritis we reanalyzed immunohistochemically the inflammatory infiltrates in sural nerve biopsies of 22 cases with Guillain-Barre syndrome (GBS) and 13 cases with chronic inflammatory demyelinating polyneuropathy (CIDP). Endoneurial infiltration of CD3+ T cells was found in 20 cases of GBS (median 5.5 cells/mm(2)) and in 10 cases of CIDP (5 cells). Epineurial T cells were present in all GBS cases (19.5 cells) and in 11 CIDP cases (21 cells). CD68+ macrophages were abundant in these neuropathies and often occurred in endoneurial perivascular clusters. In GBS subgroups the number of endoneurial T cells was significantly higher in patients with hypoesthesia and abnormal electrophysiological findings in the sural nerve. In CIDP hypoesthesia was associated with significantly higher numbers of macrophages. Our study also indicates that other factors including the time point of biopsy or previous corticosteroid treatment may influence the inflammatory cell profile. Quantifying cell infiltration may aid in establishing the diagnosis of an immunoneuropathy in patients with mild and noncharacteristic pathology.

Adult↗
PubMed1995

Effects of an antiperspirant with emollients on foot-sweat accumulation and blister formation while walking in the heat.

BACKGROUND: Friction blisters are a common injury in sports activities and military operations. Blisters can compromise performance, so it is important to devise preventive strategies to reduce these injuries. OBJECTIVE: This study investigated the influence of an antiperspirant with emollient additives on frequency and severity of friction blisters, hot spots, and irritant dermatitis. METHODS: Twenty-three healthy men walked on a treadmill (1.39 m/sec, 1% grade) in a warm environment (28 degrees C, 25% relative humidity) carrying a total mass of 21 +/- 1 kg. For 4 consecutive days before the walk, the subjects' feet were treated with either (1) an antiperspirant (20% aluminum zirconium tetrachlorohydrex glycine concentration plus water) with emollient additives, (2) emollient additives alone (placebo control), or (3) nothing (nontreated). In two separate trials (1 month apart) each participant received the antiperspirant treatment and both control treatments (emollient [placebo] and no treatment). RESULTS: No differences were seen among treatment conditions for sweat accumulation (p = 0.86), blister incidence (p = 0.36), hot spot incidence (p = 0.83), or blister severity (p = 0.31). Irritant dermatitis was not reported in any of the treatment conditions. CONCLUSION: The use of an antiperspirant with emollients reduces irritant dermatitis but does not reduce total foot-sweat accumulation, blister or hot spot incidence, or blister severity.

Adult↗
PubMed1991

Mortality in the two Germanies in 1986 and trends 1976-1986.

"Mortality data of the Federal Republic of Germany and the GDR [German Democratic Republic] are compared by age, sex and cause of death....Within the period from 1976 to 1986 life expectancy has risen in the Federal Republic of Germany, whereas in the GDR it increased to a minor extent only, so that the gap between the two parts of Germany has clearly enlarged. This enlarged gap in life expectancy largely depends on a higher mortality in the GDR due to diseases of the circular system and the respiratory organs, external influences and 'other' causes of death. The last-mentioned two groups also 'contain' the normally [separately] reported causes of death 'cirrhosis of the liver', 'suicide', 'accidents', and some diseases of the digestive system." (SUMMARY IN FRE)

Age Factors↗
PubMed1990

Synaptic analysis of amacrine cells in the turtle retina which contain tyrosine hydroxylase-like immunoreactivity.

This study examined amacrine cells in the retina of the turtle Pseudemys scripta elegans, which were labelled using an antiserum directed against tyrosine hydroxylase (an enzyme participating in catecholamine synthesis). These cells were investigated using both light and electron microscopy. Labelled somata were located in the inner nuclear layer near the border of the inner plexiform layer. The dendritic arborizations of these neurons were tristratified and arborized in strata 1 and 3 and near the border between strata 4 and 5. Serial tangential sections taken through the entire inner plexiform layer of a 1 mm-2 region in mid-peripheral retina were examined. All of the synapses associated with labelled profiles were counted and classified. The majority (84%) of the synapses involving labelled processes represented output, while the remaining 16% represented synaptic input. The synaptic output of the labelled processes was as follows: 87% onto unlabelled amacrine cells, 4% onto ganglion cells, 9% onto unidentified cell processes. None of the synaptic output from labelled processes was onto bipolar cells. The synaptic input to these labelled cells was from bipolar cells (29%) and from unlabelled amacrine cells (71%). A well labelled amacrine cell was serially sectioned and examined at the ultrastructural level to analyze its synaptic connectivity. Immunoreaction product was located diffusely throughout the cytoplasm and in large vesicles. The synaptic organization of the cell was directed primarily toward output. The labelled processes were postsynaptic and presynaptic to unlabelled amacrine cell processes in strata 1 and 3 and at the border between strata 4 and 5. Synaptic input from bipolar cells was seen exclusively near the border between strata 4 and 5. Labelled processes were presynaptic to ganglion cell processes in stratum 1 and at the border between strata 4 and 5, but not in stratum 3. Quantitative studies suggested that amacrine cell inputs and outputs were evenly distributed across the dendritic arborization, while bipolar cell inputs and outputs to ganglion cells were concentrated on the distal parts of the dendritic arborization. No labelled processes were seen in the outer plexiform layer, indicating that the cells with tyrosine hydroxylase-like immunoreactivity in the turtle retina were true amacrine cells and not interplexiform cells.

Animals↗
PubMed1990

Hereditary sensory neuropathy type II without trophic changes.

Three cases with sensory peripheral neuropathies are reported. Case 1 presented with scoliosis, and cases 2 and 3 presented with abnormal gait. None had trophic limb changes, evidence of weakness, or a tendency to self-mutilation and each had normal motor studies on neurophysiological testing. Sural nerve biopsies showed a severe loss of myelinated fibres and case 3 had evidence of denervation on muscle biopsy. These cases are presented as examples of hereditary sensory neuropathy type II. They are unusual in that they do not have trophic changes.

Adolescent↗
PubMed1988

Ventricular ectopic activity with diuretic therapy.

The arrhythmogenic potential of diuretic-induced hypokalemia in patients with uncomplicated hypertension has been controversial. Thirty-two hypertensive patients with previous diuretic-induced hypokalemia, normal 24-hour ambulatory ECG monitoring, and normal exercise testing were treated with 100 mg hydrochlorothiazide (HCTZ) daily (Group 1) to induce hypokalemia or with a combination of HCTZ with amiloride (Group 2) to attempt to maintain plasma potassium levels in the normal range during diuretic therapy. Those Group 1 patients (Group 1A) with increased ventricular ectopic activity (VEA) during HCTZ therapy were subsequently potassium-repleted with amiloride and with supplemental potassium chloride to evaluate the effect of these treatments on VEA. One Group 1 patient died suddenly after 12 days of HCTZ therapy. Autopsy findings suggested an arrhythmic death. Six Group 1 patients who had increased VEA with HCTZ treatment had reductions in VEA with amiloride or supplemental potassium chloride. Group 2 patients did not have a significant increase in VEA. Thus, diuretic therapy appears to cause VEA primarily by electrolyte changes that are induced.

Adult↗
PubMed1986

[Neurologic manifestations of ciguatera. 3 cases with a neurophysiologic study and examination of one nerve biopsy].

Ciguatera is the commonest form of poisoning resulting from eating fish in the tropics. It has been recognised since the 15th century. The disease is due to the formation of ciguatoxin by a dinoflagellate, Gambierdiscus toxicus, loosely attached to algae growing on coral reefs. The toxin, which is harmless to the fish, is ingested by small herbivorous fish and passes up the food chain as these are eaten by carnivores. The toxic effects include gastroenteritis, itching of the skin, peripheral neuropathy and central nervous system dysfunction. Though most cases are mild, occasionally the disease is severe and even fatal. There is no effective specific treatment. Three cases, of which one died and which exhibited both peripheral and central nervous system involvement, are described. Histological changes in sural nerve fibers are described. There was striking oedema of the adaxonal Schwann cell cytoplasm. These histological changes are very similar to those seen following the injection of scorpion and spider venoms into the peripheral nerve of experimental animals. Both these venoms and ciguatoxin increase the permeability of the membrane to sodium.

Adult↗
PubMed1985

Phytanic acid oxidase deficiency in childhood.

Tables 2 and 5 summarize the major clinical and biochemical findings in these patients. Cases 1 and 2 resemble clinically the previous cases of children reported as suffering from infantile phytanic acid storage disease, Zellweger's disease, or neonatal adrenoleucodystrophy. Cases 3 and 4 differ strikingly from these and from one another. Numerous questions remain unanswered, but it seems likely that these patients have in common defects in peroxisomal function which are related but not identical. Why some patients with phytanic acid oxidase deficiency do not have significant elevation of serum phytanic acid is not known. These results, however, make it clear that a normal serum phytanic acid level does not exclude phytanic acid oxidase deficiency. In children with a progressive neurological illness, with liver disease, retinal disease, unexplained neuropathy or deafness, detailed studies of fatty acid metabolism are indicated, including lipoproteins, serum phytanic acid, C26:C22 long-chain fatty acid ratios, serum pipecolic acid and phytanic acid oxidase levels. Electron microscopy of liver biopsy specimens should be considered. Phytanic acid oxidase may prove a useful marker for some of these illnesses, and its usefulness could extend to prenatal diagnosis and assist in genetic counselling.

Abnormalities, Multiple↗
PubMed1983

51Cr release cytotoxicity radioimmunoassay to detect immune cytotoxic reactions to rat Schwann cells in vitro.

Monolayers of rat Schwann cells incubated with 51Cr were used as targets for a cytotoxicity assay employing rabbit antiserum to galactocerebroside (R anti-GalC). Specific 51Cr release was demonstrated which was heat sensitive and complement-dependent. The assay was readily performed, reproducible and quantitative, and should prove useful in assessing anti-Schwann cell cytotoxic activity of experimental and human serum.

Animals↗
PubMed1979

Health effects of urban air pollution. Special consideration of areas at 1,500 m and above.

Urban air pollution, when sufficiently severe, can cause death in humans; these deaths occur preponderantly among those with increased susceptibility. Pollution--carbon monoxide and oxidants in particular--is capable of aggravating preexisting chronic heart and lung diseases. Pollution and tobacco (especially cigarette) smoke act synergistically in a causative role in chronic bronchitis and in an aggravating role in emphysema. Susceptibility to the effects of urban air pollution varies widely, with the most susceptible being fetuses, the newborn, the elderly, the infirm, those with chronic heart and lung diseases, and those who smoke. The carbon monoxide standards for sea level are probably too lenient for an altitude of 1,500 m and above. Using a broad definition of health, which takes into account concepts such as quality of life and social and mental well-being, few metropolitan residents would deny that their health is compromised by air that is malodorous, that irritates mucous membranes, and that obscures beautiful scenery.

Adult↗
PubMed1979

Hyperexcitability of motor and sensory neurons in neuromyotonia.

Two members of a family with a neuropathy resembling Charcot-Marie-Tooth disease were unable to relax their muscles after voluntary contraction. Muscle spasm often outlasted voluntary contraction by 30 seconds or more before subsiding into myokymia and fasciculations. The posture of the hand during muscle spasm resembled that of tetany, and Trousseau's and Chvostek's signs were present although no abnormality of calcium or magnesium metabolism could be demonstrated. Muscle spasms ceased during medication with carbamazepine, 600 mg daily. Nerve stimulation, electromyography, and regional neuromuscular blockade with curare indicated that the condition originated in peripheral nerve, while microneurographic recordings showed that sensory as well as motor fibers were hyperexcitable. Sural nerve biopsy revealed axonal degeneration involving myelinated and unmyelinated fibers. It was concluded that the neural hyperexcitability is caused by a membrane defect resulting in a low threshold for excitation throughout the length of the axon.

Adult↗
PubMed1979

Neuromyotonia in the spinal form of Charcot-Marie-Tooth disease.

The term neuromyotonia has been applied to spontaneous activity of peripheral motor nerves which gives rise to pseudomyotonia, muscular fasciculations and myokymia. A family is described in which 8 members of 3 generations suffer from the spinal form of Charcto-Marie-Tooth disease (distal type of chronic spinal atrophy). 5 of the 8 members were examined and found to have myokymia, accentuated by voluntary muscle contraction. Pseudomyotonia was present in 2 patients and, in the 1 patient treated, was abolished by carbamazepine. The association between neuromyotonia and charcto-Marie-Tooth disease has been reported in only 7 patients before but may be more common than previously thought because muscle cramps are reported to be a feature of this disorder.

Adult↗