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Biomedical subjects

F He

Publications and source records attributed to F He.

At least 145 records · Page 8Linked to original sources
PubMed1992

Biological monitoring of deltamethrin in sprayers by HPLC method.

Using HPLC, the authors had investigated the three metabolites of deltamethrin (DM) in the urine of spraymen and one suicide, namely: dibromovinyl-dimethylcyclopropane carboxylic acid (Br2A), 3-phenoxybenzyl-hydroxy-ethyl acetate (PHE) and 3-phenoxyl-benzoic acid (BA). Br2A was chosen as the biological monitoring parameter for DM exposed people, and the urine samples of one suicide and 11 farmers sprayed DM or DM plus methamidophos were examined for Br2A quantitatively which was detected in 8 of 11 sprayers and in the suicide case.

Agricultural Workers' Diseases↗
PubMed1991

Morphometric analysis of phrenic motoneurons in the cat during postnatal development.

The dendritic geometry of 20 phrenic motoneurons from four postnatal ages (2 weeks, 1 and 2 months, and adult) was examined by using intracellular injection of horseradish peroxidase. The number of primary dendrites (approximately 11-12) remained constant throughout postnatal development. In general, postnatal growth of the dendrites resulted from an increase in the branching and in the length and diameter of segments at all orders of the dendritic tree. There was one exception. Between 2 weeks and 1 month, the maximum extent of the dendrites increased in parallel with the growth of the spinal cord; however, there was no increase in either combined dendritic length or total membrane surface area. In addition, there was a significant decrease in the number of dendritic terminals per cell (59.8 +/- 9.3 vs. 46.4 +/- 7.4 for 2 weeks and 1 month, respectively). The distance from the soma, where the peak number of dendritic terminals per cell occurred, ranged from 700-900 microns at 2 weeks and 2 months to 1,300-1,700 microns in the adult. The diameter of dendrites as a function of distance from the soma along the dendritic path increased with age. The process of maturation tended to increase the distance from the soma over which the surface area and dendritic trunk parameter (sigma d1.5/D1.5) remained constant. The three-dimensional distribution of dendrites was analyzed by dividing space into six equal volumes or hexants. This analysis revealed that the postnatal growth in surface area in the rostral and caudal hexants was proportionately larger than that in either the medial, lateral, dorsal, or ventral hexants. Strong linear correlations were found between the diameter of the primary dendrite and the combined length, surface area, volume, and number of terminals of the dendrite at all ages studied.

Animals↗
PubMed1991

3-Nitropropionic acid-exogenous animal neurotoxin and possible human striatal toxin.

3-Nitropropionic acid (3-NPA)--a suicide inhibitor of succinate dehydrogenase--is a widely distributed plant and fungal neurotoxin known to induce a damage to basal ganglia, hippocampus, spinal tracts and peripheral nerves in animals. Recent reports from Northern China indicate that 3-NPA is also likely to be responsible for the development of putaminal necrosis with delayed dystonia in children after ingestion of mildewed sugar cane. This article discusses the role of 3-NPA in the causation of the disease in China, its neurotoxic effects in animals and the potential role for this compound as a probe of selective neuronal vulnerability.

Animal Diseases↗
PubMed1990

The yeast Yarrowia lipolytica has two, functional, signal recognition particle 7S RNA genes.

Cells containing a deletion of either the SCR1 or SCR2 genes, which code for the 7SL RNA component of the signal recognition particle (SRP) homologue, were found to be viable. Two independent approaches demonstrated that cells containing deletions of both genes were inviable. Therefore, Yarrowia lipolytica contains two (and only two) functional 7SL RNA genes.

Blotting, Southern↗
PubMed1989

Clinical manifestations and diagnosis of acute pyrethroid poisoning.

This article reviews 573 cases of acute pyrethroid poisoning reported in the Chinese medical literatures during 1983-1988. There were 325 cases of acute deltamethrin poisoning (occupational 158, accidental 167), 196 patients of acute fenvalerate poisoning (occupational 63, accidental 133, including 2 cases of ingestive fenvalerate-organophosphate mixture poisoning), 45 cases of acute cypermethrin poisoning (occupational 6, accidental 39) and 7 cases of other pyrethroid poisoning (occupational 2, accidental 5). The clinical manifestations have been reviewed and analysed. The diagnosis, gradation and differential diagnosis of occupational acute pyrethroid poisoning have been discussed.

Adult↗
PubMed1989

Two genes encode 7SL RNAs in the yeast Yarrowia lipolytica.

We have identified an abundant cytoplasmic 7S RNA in crude extracts of the yeast Yarrowia lipolytica. A cDNA probe was prepared from this RNA and used to screen a genomic library. The DNA sequence of a positive clone was determined and the end positions of the 7S RNA gene established by comparison with the sequence of the extremities of 7S RNA. This gene, designated SCR2, encodes a 270-nucleotide RNA that can be folded into a secondary structure similar to that of 7SL RNAs. This RNA is 94.4% homologous to a previously identified 7S RNA from this yeast, but is encoded by a separate gene with highly divergent flanking sequences.

Base Sequence↗
PubMed1989

[Studies on the immunoregulative action of polysaccharides isolated from hyphal bodies of Lentinnus edodes (PHL) on hypoimmunity in mice].

PHL possesses significant antagonist action for immunodepression in mice induced by different immunodepressors. It can reverse the hypomacrophage function and the reduction in percentage of T-lymphoid cell induced by hydrocortisone (50 or 80 mg/kg, sc), reverse the reduction of phagocytosis of reticuloendothelial system (RES) induced by hydroprednisone acetate (20 and 40 mg/kg, ip), restore the cyclophosphamide-suppressed delayed anaphylaxis reaction in mice (40 and 80 mg/kg, ip). In vitro PHL at a dose of 1 and 10 micrograms/ml accelerated lymphocyte mitosis induced by conA and PHA.

Animals↗
PubMed1988

Effects of pyrethroid insecticides on subjects engaged in packaging pyrethroids.

A health survey was conducted on 199 workers engaged in dividing and packaging pyrethroids. The subjects were exposed to fenvalerate at 0.012-0.055 mg/m3 and deltamethrin at 0.005-0.012 mg/m3 in the air with simultaneous skin contact for 0.5-4.5 months. Burning sensations and tightness or numbness on the face appeared in two thirds of the subjects and one third had sniffs and sneezes. Abnormal facial sensations, dizziness, fatigue, and miliary red papules on the skin were more evident in summer than in winter. Neither abnormalities in other organs or systems nor symptoms or signs of acute pyrethroid poisoning were found by interviews, examinations, and laboratory tests. There was no significant difference in plasma levels of NA, cAMP, and cGMP between the examined subjects and the control group. The urine concentration of fenvalerate in the study group ranged from 1.02 to 18.6 micrograms/l; deltamethrin in the urine was present in trace amounts.

Adolescent↗
PubMed1985

Occupational toxic neuropathies--an update.

Peripheral neuropathy is the commonest neurological syndrome produced by industrial and agricultural chemicals. A number of chemicals have been recently found to be neurotoxins; in addition some known occupational neurotoxic hazards more often produce subtle alterations in the peripheral nervous system. There have been problems of both evaluating neurotoxic effects and identifying toxic causes. This article reviews and discusses the current research and progress covering neurophysiological, neuropathological, biochemical, and epidemiologic approaches in clinical and experimental neurotoxicology, as related to the assessment and pathogenesis of occupational toxic neuropathies.

Axons↗
PubMed1983

A combined morphological and electrophysiological study of conduction block in peripheral nerve.

The reliability of the electrophysiological criterion of conduction block in determining the presence of focal demyelination in a peripheral nerve has been studied in an animal model. Demyelination was produced in the rat tibial nerve by one or two closely spaced microinjections of lysophosphatidylcholine (LPC). Histological and electrophysiological data were obtained on the acute lesion (up to 6 days), and during recovery (up to 11 weeks). Single LPC injections produced a lesion of very variable severity. Double injections more reliably produced a severe lesion with marked conduction block. Slight axonal damage was occasionally seen in nerves showing severe demyelination. The ratio of amplitude of muscle action potentials evoked by stimuli proximal and distal to the sites of nerve injection was calculated to detect the development of conduction block. The post injection ratio was more than 2 standard deviations below the control mean in 86% of nerves showing signs of demyelination. No control saline injected nerves showed such evidence of conduction block. The severity of the electrophysiological abnormality did not prove a reliable indicator of the severity of the histological lesion, however. The possible reasons for this variability are discussed and it is argued that caution should be exercised when interpreting this particular electrophysiological finding in clinical practice.

Animals↗
PubMed1981

The pathology of allyl chloride neurotoxicity in mice.

Allyl chloride is known to produce a neuropathy in man after occupational exposure to its vapour. The present study describes the neuropathy which develops in mice given allyl chloride by mouth. Mice were dosed three times weekly with 300 or 500 mg/kg allyl chloride for periods from 2-17 weeks. Functional disability was observed in some animals. Apart from evidence of focal kidney damage in 70% of dosed mice, pathological changes were restricted to the nervous system. Nerve fibre degeneration was found in many peripheral nerves and in roots, tending to be more marked distally and to affect more motor than sensory nerves. Degenerated fibres were also found in dorsal, ventral and lateral columns of the spinal cord. Males were more severely affected than females. Increased numbers of filaments were on early axonal change, occurring multifocally and apparently preceding axonal degeneration. No neuronal death was observed, but occasional anterior horn and dorsal root ganglion cells showed some morphological changes. Vacuolated lesions mainly due to swelling of astrocytes and their processes were found in the ventral horn in cervical and lumbar regions of spinal cord. Animals appeared to become tolerant to allyl chloride after continuous dosing. This neuropathy appears to be a central-peripheral distal type of axonopathy.

Allyl Compounds↗
PubMedDate not supplied

3-Nitropropionic acid produces indirect excitotoxic damage to rat striatum.

The mechanism of striatal damage induced by 3-nitropropionic acid (3-NPA) was studied in rats by neuropathological and neurochemical methods. Neuronal shrinkage with astrogliosis was observed in striatum after local injection of 0.5-5 mumol 3-NPA. Decortications involving dorsal and lateral aspects of frontal cortex or both frontal and parietal cortices significantly decreased the severity of striatal injuries induced by 3-NPA. This result suggests that corticostriatal projections play an important role in the development of striatal damage. No significant increase of glutamate and aspartate in striatal dialysates was observed, which indicated that 3-NPA may affect the postsynaptical sites and make the striatal neurons more vulnerable to endogenous levels of glutamate. Both of these findings suggested that 3-NPA produces indirect excitotoxic lesion to striatum. An increase of dopamine found in striatal dialysates may also be related to the occurrence of striatal damage.

Animals↗
PubMedDate not supplied

Consistent striatal damage in rats induced by 3-nitropropionic acid and cultures of arthrinium fungus.

Arthrinium fungi were cultivated from the samples of mildewed sugarcane which caused acute encephalopathy and delayed dystonia in children. The Arthrinium cultures (AC) contained 5 mg/ml 3-nitropropionic acid (3-NPA) after being inactivated and concentrated. A neuropathological study was carried out in rats intoxicated with 3-NPA and AC, respectively. Consistent bilateral striatal necrosis was found in rats with both poisonings, and the severity was well correlated with persistent recumbency which was a clinical indicator of the development of morphological brain lesions. A reproducible animal model of striatal damage has been produced in rats by IP injections of 10 mg/kg 3-NPA, 6 times a day, with an interval of 1.5 h for 3-5 days. The clinical and neuropathological manifestations in rats dosed with AC were nearly the same as those dosed with 3-NPA. The striatal lesions induced by 3-NPA and AC in poisoned rats were in accordance with the bilateral lenticular hypodensity found by CT scanning in patients of mildewed sugarcane poisoning with delayed dystonia. This neuropathological evidence supports previous epidemiological and mycological findings which indicate that 3-NPA is the possible pathogen of acute mildewed sugarcane poisoning.

Animals↗