Ultrastructure and x-ray microanalysis of siderosome

Comparative ultrastructural examination and energy-dispersive electron probe X-ray microanalysis were performed on a long standing skin lesion of hemosiderotic histiocytoma. Iron-containing fine particles present in siderosome were the main element of interest. Qualitative study of spectra over the siderosomes clearly demonstrated the characteristic X-ray energy emitted by iron, whereas spectra obtained from adjacent cytoplasm revealed minimal iron peak. On quantitative evaluation of the spectra yielded from various siderosomes, iron counts intensity was found to be proportionally increased with increment in amount and electron opacity of the siderosomal inclusion. Accounts on chemical nature of the siderosomal inclusion and on the presence of lipid residue in cytoplasms were noted.

Experimental gingivitis in ODU plaque-susceptible rats. II. Biochemical nature of the rat plaque

The characterization of the dental plaque from ODU plaque-susceptible rats is reported. The comparison between the rat dental plaque and a human dental plaque indicates that content of extractable hexose and inorganic salts and amino acid composition are different from each other. Electron microscopic study indicates that bacterial flora of the rat dental plaque seems to be little different from a human dental plaque. In spite spite of obvious differences in biochemical nature between the rat dental plaque and the human dental plaque, there are enough similarities to warrant intensive investigation regarding the relationship between the dental plaque and gingivitis.

["Methamphetamine-stereotypies" and brain dopamine levels of rats treated with single or repeated doses of alpha-methyl-para-tyrosine (author's transl)]

Male albino Wistar rats were injected intraperitoneally with saline solution (1.0 ml/kg) or a-methyl-paratyrosine (50 mg/kg) once or daily X 7 and methamphetamine (10 mg/kg) was injected 3 hr or 24 hr after the last injection of these drugs. Stereotyped licking and biting activity were scored during 120 min after methamphetamine injection and, in parallel brain dopamine levels were measured. Methamphetamine given 3 hr after single or repeated administrations of alpha-methyl-para-tyrosine was not effective for stereotyped behavior and brain dopamine levels in similarly treated rats decreased markedly in comparison with saline-treated rats. Methamphetamine 24 hr after repeated administration of alpha-methyl-para-tyrosine clearly induced stereotypies and brain dopamine levels in these rats did not differ from saline-treated rats. The results suggest a possible role of brain dopamine on "methamphetamine-stereotypies".

Experimental gingivitis in ODU plaque-susceptible rats. I. Changes of plaque formation and body weight

New strains of ODU plaque-susceptible and resistant rats have been developed starting from litter mating at our laboratory, in 1972. Those strains were selected and mated for further generations. ODU plaque-susceptible and resistant rats are those that show the presence or absence of plaque formation in their gingiva of lower incisors after they are fed a commercially available powder diet. Experiments were started when rats weighing 75 to 85 gm were about 5 weeks old being fed with 20 gm of a powder diet a day. Almost every 4 days, plaque formation was observed in terms of 5 degrees from zero to 4 degrees and body weight. As a result, plaque formation in plaque-susceptible and resistant rats clearly showed their quality in their 3rd generation. Those qualities will be further emphasized as the generation advances. In the 3rd generation of plaque-susceptible rats, no difference was found in growth between those ingested with a powder diet and those with a solid diet of the same ingredients. But in the first 2 months, male plaque-resistant rats of the 3rd generation grew more quickly than susceptible rats.

Metabolic mapping of the primary visual system of the monkey by means of the autoradiographic [14C]deoxyglucose technique

An autoradiographic technique that employs 2-[14-C]deoxyglucose to measure the local rates of glucose utilization within the brain has been applied to the binocular visual system of the Macaque monkey. This method, which pictorially displays the relative rates of glucose consumption in the component structures of the brain, delineates the regions of altered functional activity because of the close relationship between functional activity and energy metabolism. Bilateral retinal stimulation results in the delineation of different rates of glucose consumption in at least four cytoarchitectural layers of the striate cortex. The most intense metabolic activity appears to be in Layer IV, the locus of the termination of the geniculocortical pathway. Bilateral visual occlusion lowers the rates of glucoes consumption in striate cortex and markedly reduces the metabolic differentiation of the various layers. Unilateral visual deprivation delineates the laminae of the lateral geniculate body and the ocular dominance columns of the striate cortex. It also results in the autoradiographic visualization of regions with normally monocular input in the striate cortex, such as the rostral portions of the mushroom-like configurations in the calcarine cortex, which represent the extreme temporal crescents of the visual fields, and small regions in the most caudal part of the mushroom configurations, which are believed to represent the cortical loci of the blind spotsof the visual fields.