The evaluation of a new synthetic pyrethroid pesticide (permethrin) for neurotoxicity

A new synthetic pyrethroid, permethrin, has recently been granted a registration by the United States Environmental Protection Agency. Permethrin and a large number of other chemicals of its type are expected to receive widespread use in the environment in the near future. Since the mechanism by which these compounds exert their toxic effect in insects (and at higher doses in mammals) is by disruption of the normal function of nervous tissue, a detailed morphologic evaluation of the nervous system was performed on rats from two long-term feeding studies conducted on permethrin. In this evaluation, examination of central and peripheral nervous plus examination of extensive morphometric data and teased myelinated fibers of distal sural and tibial nerves and of the maxillary division of cranial nerve V did not reveal any changes which could be attributed to the feeding of the pesticide.

Acinic cell carcinoma arising in the glossopalatine glands: a report of two cases with electron microscopic observations

Two cases of acinic cell carcinoma arising in the glossopalatine glands were examined with the electron microscope by means of conventional thin sectioning and freeze-fracturing. Light and electron microscopic observation revealed that the tumors consisted of three types of cells: serous-type, ductlike, and vacuolated cells. Serous-type cells had numerous secretory granules, some of which were discharged into the intercellular spaces. Ductlike cells were smaller, usually lacked secretory granules, and were similar to intercalated duct cells. Vacuolated cells had electron-opaque vacuoles in the cytoplasm. Our findings supported the hypothesis that acinic cell carcinoma may represent a neoplasm of multipotential duct cells which have differentiated mainly into granulated serous cells. Freeze-fracture images of this tumor revealed that tight junctions were composed of ten or more interlinked strands with elongation of basal frontier strands. These findings suggested that the junctional morphology of the tumor resembled that of developing salivary glands and was associated with the degree of cellular differentiation.

Intercellular junctions in odontoblasts of the rat incisor studied with freeze-fracture

The morphology and distribution of various types of intercellular junctions were investigated in young odontoblasts. Gap junctions were found between odontoblasts as well as between odontoblasts and fibroblasts in the dental pulp. The junctions between odontoblasts were larger and more numerous than those between odontoblast and fibroblast, suggesting that the former may play an important role in regulating cellular activity and the latter may provide a pathway of low electrical resistance between odontoblast and nerve fibres. Irregularly-shaped gap junctions appeared as small aggregations of particles associated with a particle-free area and may indicate that the junction might not yet have been completely assembled. Tight junctions were observed at the distal ends of the young odontoblasts, arranged to form small maculae or faciae occludentes rather than belt-like zonulae. It is therefore not likely that the junction contributes to barrier function in the young odontoblasts. Although structures resembling typical desmosome were recognizable, this type of junction in odontoblasts is properly termed a desmosome-like junction from its morphological peculiarities.

[Case of Borrmann III stomach cancer effectively treated by UFT therapy (co-administration of uracil and futraful)]

Through X-ray and endoscopic examination of stomach, a 77 year-old man, who complained of epigastralgia, he was diagnosed to have Borrmann III type gastric carcinoma on the antrum. The gastric biopsy specimen obtained from the tumor revealed to be well differentiated adenocarcinoma. Since the patient refused receiving surgical treatment, a combined administration of futraful and uracil (UFT therapy) was performed. 4 weeks after receiving UFT therapy, the patient became less aware of subjective symptom and the gastrofiberscopic picture showed smaller mass lesion compared to that of prior to the treatment. 8 weeks later, the tumor was remarkable reducing its size. When compared 14 cases of gastric carcinoma receiving UFT therapy with 26 cases receiving Futraful therapy (FT therapy), the UFT group responded more effectively than the FT group. In the UFT therapy, complete (CR) and partial response (PR) were obtained in 4 of 13 cases of gastric carcinoma with an effective rate of 30.8% according to the response criteria proposed by the Koyama-Saitoh group and with a Karnofsky scale of IA or better in 6 (42.8%) of 14 cases. On the other hand, in the FT therapy CR and PR were obtained in 5 of 26 cases with that of 19.2%, while a Karnofsky scale of IA or better was achieved in 6 (23.1%). As for 3 cases of PR in the UFT therapy the microscopic view of the biopsy specimen from gastric carcinoma showed well differentiated adenocarcinoma, which responded to the UFT therapy remarkably 4-5 weeks after receiving UFT therapy.

Morphometric comparison of the vulnerability of peripheral motor and sensory neurons in amyotrophic lateral sclerosis

The diameter histograms of cell bodies (cytons) in motor neuron columns at the L5 segment of the spinal cord of adult man reproducibly yield three peaks of increasing height: small (Cs), intermediate (Ci), and large (Cl). Histograms of L5 myelinated axons obtained from the ventral root have two peaks of increasing height: intermediate (Ai) and large (Al). In histograms prepared from seven cases of amyotrophic lateral sclerosis (ALS), the Cl and Al peaks were decreased selectively and severely. This provides evidence for alpha, but not gamma, motor neuron vulnerability. The Cl peak of spinal ganglion neurons and the Al peak of dorsal roots were significantly reduced in number, without a concomitant increase in Ci, Cs, and Ai peaks. This, plus earlier reports of abnormal cutaneous sensation thresholds, abnormal rates of fiber degeneration in cutaneous nerves, and dorsal column demyelination, provides evidence that large afferent neurons are affected in ALS, but to a lesser degree than alpha motor neurons.

The number and sizes of reconstructed peripheral autonomic, sensory and motor neurons in a case or dysautonomia

Motor, spinal ganglion, intermediolateral and sympathetic trunk neurons were reconstructed by morphometric sampling of their cell bodies at L5 and T7 segments and at various levels of spinal roots and peripheral nerves in a 31-year-old patient with dysautonomia and compared to reference cases. The patient had strikingly fewer intermediate motoneuron column neurons and intermediate ventral root axons (probably gamma motoneurons), spinal ganglion neurons, preganglionic autonomic neurons and sympathetic trunk neurons that did controls (approximately 10--30% of reference values). The striking agreement between selective absence of intermediate-diameter cytons (Ci) and of intermediate diameter myelinated fibers (Ai), which are thought to be gamma efferent, of L5 motoneuron columns provides further confirmation to our previous suggestion that the Ci peak of motoneuron columns are somas of gamma efferent neurons. The number and size of alpha motoneuron cell bodies and their proximal axons were like those of controls but their distal axons were probably atrophic. This finding probably explains the small reduction in maximum conduction velocity of motor nerve fibers found in this disorder. The brunt of the pathologic process in this disorder has been borne by intermediate and small neurons preferentially.

3,3'-Iminodipropionitrile induced centrifugal segmental demyelination and onion bulb formation

Centrifugal segmental demyelination extended from the proximal to the distal portion, and onion bulb formation in the extraspinal ventral root occurred following the axonal lesion of the intraspinal ventral root induced by 3,3'-iminodipropionitrile. These results suggest that axonal factors may be responsible to segmental demyelination and onion bulb formation.

Endoscopic studies on the minute structures of colonic mucosa in the follow-up observation of ulcerative colitis

Thirty cases of ulcerative colitis were examined endoscopically by means of magnifying colonoscope with dye spraying method (the combined method), and their minute mucosal structures were classified into four categories endoscopically, which correlated well with the histological findings. By this procedure, it was easy to detect the subsidence of inflammation of the mucosa in the quiescent phase or to reveal the active inflammatory involvement of the bowel. Moreover, inspecting the minute changes of the colonic mucosa detected by the combined method, remission was more correctly decided and rigid control is contributing to the decrease in the recent rate of recurrence of ulcerative colitis.

Chronic alcoholism: report of an autopsy case and comparison with pseudoulegyric type of hepatocerebral degeneration

An autopsy case diagnosed as chronic alcoholism was reported. He clinically showed progressive neurological illness. His CNS lesions were composed of disseminated necrotic foci in the cerebral cortices with many Alzheimer type II astrocytes, pachymeningitis hemorrhagica interna, and lesions similar to pellagra and Wernicke encephalopathy. Some clinical and pathological analogous features between chronic alcoholism and pseudoulegyric type of hepatocerebral degeneration were discussed.