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Biomedical subjects

C G Wright

Publications and source records attributed to C G Wright.

At least 73 records · Page 4Linked to original sources
PubMed1982

Concentration and movement of diazinon in air.

Airborne concentrations of diazinon were measured in rooms for 21 days after crack and crevice application. Residue levels were largest in treated rooms (38 micrograms/m3) after application, followed by adjacent (1 microgram/m3) and upper and lower rooms (ca. 0.4 microgram/m3). Low levels of diazinon were detected in all rooms 21 days after application. Small amounts of diazinon (corrected to an 8 min application period) were detected on respirator pads (2.6 microgram) and waist pads (2.3 microgram) worn by the applicator.

Air Pollutants↗
PubMed1982

Inner ear histopathology in patients treated with cis-platinum.

Temporal bone histopathology was studied in five patients (aged 51-67) who received cis-diamminedichloroplatinum (DDP) chemotherapy for head and neck squamous cell carcinoma. In each case, sensorineural hearing loss occurred during the course of treatment and temporal bones were acquired 3-5 hours postmortem for anatomical study. Scanning electron microscopy revealed acute degenerative changes in cochlear hair cells that appeared to be the result of drug treatment. However, the presence of age-related degeneration made it difficult to unequivocally identify hair cell loss due solely to ototoxicity. In one patient, a decrement in vestibular function was observed during DDP treatment. Postmortem examination showed severe degeneration of the maculae and cristae which could be correlated with the absence of caloric response seen after chemotherapy.

Aged↗
PubMed1981

Cis-platinum vestibular toxicity.

Cis-diamminedichloroplatinum has been proven to be an effective neoplastic agent. Nephrotoxicity and ototoxicity are two prominent side effects of this drug. Investigation of ototoxicity has been limited to auditory function. This report details the first known case of vestibular toxicity following platinum therapy. In addition, a prospective vestibular testing program is reported.

Aged↗
PubMed1981

Hereditary deafness with hydrops and anomalous calcium phosphate deposits.

The temporal bones from a 58-year-old white woman who had had hereditary congenital deafness were examined with the techniques of microdissection and surface preparations followed by sectioning of the modiolus. There was bilateral, almost total sensorineural degeneration, which also involved the saccule. The degeneration of the distal processes of the cochlear neurons in the osseous spiral lamina was almost complete, whereas numerous ganglion cells and proximal processes remained in the modiolus and the internal auditory canal. Severe cochleo-saccular hydrops was present in the left ear with Reissner's membrane bulging into the horizontal canal. X-ray diffraction and electron probe analysis were used to study the abnormal crystalline deposits in both ears. On the left side the saccular otoconia were composed of calcite, but the utricular macula was covered by a crust of apatite spherulites. More apatite occurred around the maculae and in the scala media. The cupulae were composed of apatite and octacalcium phosphate. On the right side the utricular otoconia were of normal calcite, but there was a deposit of apatite on the macula sacculi. The upper part of the scala media was completely filled by a deposit of apatite and octacalcium phosphate.

Adolescent↗
PubMed1981

Ear anomalies in an infant with Potter's syndrome.

Microdissection and scanning electron microscopy were used to study temporal bone specimens from a newborn infant with Potter's syndrome. The 34-year-old mother of the infant had juvenile-onset rheumatoid arthritis and she took prostaglandin inhibitors (aspirin, indomethacin, and Clinoril) during pregnancy. Autopsy findings included bilateral renal dysgenesis, pulmonary hypoplasia, abnormal facies with low-set ears, and bilateral cataracts. The infant's left external ear canal was stenotic and the left tympanic anulus was narrowed. Otherwise, both middle ears, as well as the sensory structures of the cochleae and semicircular canals, were normal. The saccular and utricular muculae on the right were entirely devoid of otoconia, although they were covered by gelatinous otoconial membranes which appeared normal. On the left, the maculae were covered by thin layers of flat, lenticular crystals 2 to 10 mu in diameter. X-ray powder diffraction analysis showed these aberrant otoconia to be composed of calcium carbonate in the form of vaterite. No abnormalities of the neuroepithelia or macular nerve supply were found in either ear.

Cataract↗
PubMed1979

Effects of genetic vestibular defects on behavior related to spatial orientation and emotionality.

A large battery of behavioral tests was administered to normal mice and to mice with varying degrees of otoconial agenesis due to genes affecting vestibular development. Many significant differences were found, but a factor analysis revealed that the variance on the 11 best tests could be accounted for in terms of two underlying variables. Factor I, the more important of the two, was associated with activity, habituation, and spontaneous alternation. Factor II appeared to represent a fear of new stimuli or situations. In both cases factor scores were highly related to the degree of otoconial deficiency. One subgroup of mice with severe otoconial agenesis displayed hyperactivity and a total absence of either habituation or spontaneous alternation. In these animals, brain and body development were stunted, and the reactions to amphetamine and physostigmine were opposite to those seen in normal mice. The results support the idea that the static organs contribute importantly to spatial orientation and suggest that early-onset vestibular defects can result in profound alterations of emotionality.

Acetylcholine↗
PubMed1976

Insecticide movement following application to crevices in rooms.

The movement of chlorpyrifos and diazinon from cracks and crevices in empty dormitory rooms with and without forced air movement to houseflies and plates in non-target areas was studied. Aluminum pie plates in rooms with the high concentrations of an insecticide, no forced air movement, and at the earlier sampling interals contained more insecticide. Insecticides were not detectable at 48 hr. Increased housefly movement occurred simultaneously with the initiation of insecticide application in rooms with forced air and 1 min later in rooms with no forced air. Mortality of houseflies exposed during and at 5 hr after insecticide application was greater for males than females in all tests except one; at the high insecticide concentrations; and at successive time intervals through the 24-hr interval after their transfer from the treated rooms to holding rooms. Houseflies in cages near the ceiling, exposed to an insecticide, and forced air movement, exhibited greater mortality than those in cages on the floor, while the reverse was true for houseflies in rooms with no forced air movement.

Air Movements↗