Biomedical subjects

A Shimozawa

Publications and source records attributed to A Shimozawa.

35 records · Page 2Linked to original sources

PubMed1986

The ultrastructure of hemolymph cells of the land slug, Incilaria fruhstorferi Collinge (Gastropoda: Pulmonata).

3 morphologically distinct hemolymph cell-types, Type I, II and III, were found in the hemolymph of the land slug, large Japanese native slug, Incilaria fruhstorferi Collinge. Type I cell, measuring approximately 35 microns in diameter, had extensive pseudopodia with supporting ribs and a kidney-shaped or lobulated nucleus. Sometimes it possessed long filopodia (approximately 50 microns) with branched fibers. It contained residual bodies, multivesicular bodies, Golgi apparatus, free ribosomes and glycogen-like deposits. Type II cell, approximately 5 microns in diameter, did not form large pseudopodia, had a higher nucleus to cytoplasm ratio. It contained scattered free ribosomes surrounding the round nucleus. Type III cell, approximately 75 X 15 microns, was a fibroblast-like cell. It contained microfibrils at the rim of perinuclear cytoplasm and possessed collagen-like fibers outside of the cytoplasmic membrane. Numerous plate-like structures, which had not been reported yet, were usually observed. They, measuring 1 to 5 microns in diameter, were oval, but when in contact with glass, they possessed long and fine fibers. They lacked nucleus.

Animals↗

PubMed1985

Nerve fiber caliber analyses in the mouse ramus digastricus and rami stylohyoidei with the electron microscope.

2 nerve branches to the m. stylohyoideus are found in the mouse. One of them (r. stylohyoideus proximalis) arises from the posterior side of the truncus facialis just under the crossing and contacting region with the r. auricularis n. vagi and just proximal to the origin of the r. digastricus. It passes postero-medially along the r. auricularis n. vagi and enters the region of the origin of the m. stylohyoideus. The other branch (r. stylohyoideus distalis) arises as a common branch with the r. digastricus, passes postero-media-inferiorly and separates from the r. digastricus on the way. The myelinated fibers of the r. digastricus and the rr. stylohyoidei derive from the large fiber zone of the truncus facialis. But they are considerable larger than those in the large fiber zone. While they are scattered in the more proximal truncus facialis, they gradually become crowded as they come near to the origins of these rami. On the average, the r. stylohyoid, prox., the r. stylohyoid. dist., and the r. digast. contain 15, 16 and 49 myelinated fibers and 5, 13 and 24 unmyelinated fibers respectively. About 67% of the myelin sheaths of the r. digast. and about 71% of those of the rr. stylohyoid. prox. et dist. are 3-5.5 micron in minor diameters. About 64% of the axons of the myelinated fibers of these rami are 2-4 micron in minor diameters. The frequency distributions of minor diameters of the myelin sheaths and axons of the myelinated fibers of these rami show that they are approximately 1 micron larger than those of the large fiber zone of the motor root of the n. facialis and the truncus facialis distal to the foramen stylomastoideum.

Animals↗

PubMed1984

Nerve fiber caliber analysis in the mouse facial trunk distal to the stylomastoid foramen with the electron microscope.

Nerve fiber counts and caliber analysis were performed with the electron microscope on 5 facial trunks distal to the stylomastoid foramen from 3 mice. On an average, about 89% of the total nerve fibers (3,205) were myelinated and about 11% unmyelinated. Majority (80.5%) of the myelin sheaths of the myelinated fibers in the nerves were 2.0-4.5 microns and majority (86.4%) of their axons were 1.0-3.0 micron in minor diameter. Their frequency distributions were similar in pattern to that of the large fiber zone of the motor root of the mouse facial nerve. Majority (86%) of the unmyelinated fibers in the facial trunk distal to the stylomastoid foramen were 0.1-0.5 micron in minor diameter. Its frequency distribution showed that the unmyelinated fibers of the facial trunk tend to be rather smaller than that of the other nerves examined in the previous studies. Ratios of the circumferential length of the myelinated fibers to that of the circles with the same areas ranged from 1.00 to 1.98, with 1.02-1.10 being most frequent (72%). Ratios of the axons of the myelinated fibers ranged from 1.00 to 2.54, with 1.04-1.14 being most frequent (51.8%). Ratios of the unmyelinated fibers ranged from 1.00-1.18 (84%), and those which over 1.20 were rare.

Animals↗

PubMed1982

Nerve fiber caliber analysis in the mouse intermediate nerve with electron microscope.

A nerve fiber caliber analysis was performed by electron microscope on 6 intermediate nerves from 5 mice. Majority (86.5%) of the myelin sheaths of the myelinated fibers in the intermediate nerves ranged from 1 to 2 micrometers in minor diameter, and majority (85.7%) of their axons ranged from 0.4 to 1.2 micrometers in minor diameter. The intermediate nerves contained small myelinated fibers at much higher percentage than the large fiber zone of the motor roots of the facial nerves, while it did not show significant difference from the small fiber zone of the motor roots. However, frequency distribution of myelin sheaths of the myelinated fibers of the intermediate nerves may tend to be a little larger than that of the small fiber zone of the motor roots, while frequency distribution of their axons may incline to the more or less smaller than that of the small fiber zone of the motor roots. Majority (72.4%) of the unmyelinated fibers in the intermediate nerves ranged from 0.3 to 0.7 micrometers in minor diameter. Unmyelinated fibers of the intermediate nerves showed similar pattern of diameter frequency distribution with that of the motor roots of the facial nerves and the deep petrosal nerves. The diameter frequency distribution of the myelin sheaths, the axons of the myelinated fibers and the unmyelinated fibers in the intermediate nerves were constantly unimodal.

Animals↗

PubMed1981

Fiber analysis of the motor root of the mouse facial nerve.

A nerve fiber caliber analysis was performed with the electron microscope on the motor root of the facial nerve in 5 mice. The large fiber zone of the motor root contained large myelinated fibers at higher percentage than the smaller fiber zone, while the latter contained small myelinated fibers at higher percentage than the former. On the other hand, diameter frequency distribution of unmyelinated fibers did not show significant difference between the large and the small fiber zones. It is postulated that diameter frequency distribution of unmyelinated fibers may be about the same in various nerves, although that of myelinated fibers show contrast between the nerves with different functions.

Animals↗

PubMed1979

Ganglion cells in the facial nerve trunk of the mouse.

Numbers and distribution of the ganglion cells in the facial trunk distal to the ggl. geniculi of the mouse were examined with the light microscope. Counts of the ganglion cells in 22 nerves from 14 mice showed that all specimens contained some ganglion cells and numbers of the ganglion cells were various (1--80) and, on an average, there were 24 ganglion cells in each facial trunk. Ganglion cells existed most frequently in the dorsal corner and the dorso-lateral border of the small fiber zone of the facial trunk near the level of the origin of the n. stapedius. Also they were often found in the facial trunk near the origin of the chorda tympani and near the cross contact of the r. auricularis n. vagi with the facial trunk. These ganglion cells may be sensory neurons.

Animals↗

PubMed1978

Electron-microscopic analysis of the mouse facial nerve near the geniculate ganglion.

An electron-microscopic analysis of the mouse facial nerve near the geniculate ganglion shows that there are, on the everage, 603 more nerve fibers in the portion of the nerve distal to the geniculate ganglion than there are in the part proximal to the ganglion. The average distal increase in the number of unmyelinated fibers is 444 and that in the myelinated fibers is 165. The somatic motor nerve fibers and the parasympathetic fibers in the mouse facial nerve may not contribute to the distal excess. It is possible that the increase in the number of unmyelinated fibers distal to the geniculate ganglion is mainly due to the presence of postganglionic sympathetic fibers in the facial trunk distal to the geniculate ganglion and the greater petrosal nerve. The distal increase in the number of myelinated fibers may be mainly contributed by the sensory fibers.

Animals↗

PubMed1978

Quantitative studies on the nervus stapedius of the mouse with the electron microscope.

A nerve fiber count analysis was performed with the electron microscope on the nerve to the stapedius in seven mice. On an average, 77 (81%) of the total nerve fibers (95) were myelinated and 18 (19%) unmyelinated. The nerve consisted mostly of large myelinated fibers, minor diameters of which measured 3-4 micrometer most frequently like the large fiber zone of the motor root of the facial nerve and the facial trunk. The nerve fibers to the stapedius come from the large fiber zone of the facial nerve trunk.

Animals↗

PubMed1976

Quantitative studies on the mouse facial nerve trunk distal to the geniculate ganglion. An electron-microscopic study.

A fiber count analysis was performed with the electron microscope on the facial nerve trunk distal to the geniculate ganglion in seven mice. On an average, 4,836 (93%) of the total nerve fibers (5,201) were myelinated and 328 (6.3%) unmyelinated. The large part of the nerve consisted mostly of large myelinated fibers (large-fiber group). The small part of the nerve consisted of small myelinated and unmyelinated fibers (small-fiber group). The fiber constitution of the small-fiber group in the nerve was more like that in the intermediate nerve than that of the small-fiber group in the motor root of the facial nerve. Thus, it is postulated that the nerve fibers of the small-fiber group in the facial nerve trunk distal to the geniculate ganglion may be derived from the intermediate nerve, and that the nerve fibers of the small-fiber group in the motor root of facial nerve may course to the greater petrosal nerve.

Animals↗

PubMed1975

Quantitative studies on the intermediate nerve of the mouse with the electron microscope.

Quantitative counts of the intermediate nerve fibers of the mouse with electron microscope have shown that, on an average, 1,267 (79.3%) and 301 (18.9%) of the total nerve fibers (1,597) were myelinated and unmyelinated fibers, respectively. The number of unmyelinated fibers in the intermediate nerve was less than one-half the number of unmyelinated fibers in the greater petrosal nerve found in previous studies. Therefore, it is postulated that some of the unmyelinated fibers in the greater petrosal nerve may come from the intermediate nerve, while the rest may be derived from another source.

Animals↗

PubMed1975

Quantitative studies on the motor root of the mouse facial nerve. An electron-microscopic study.

Fiber count analysis was performed with the electron microscope on the motor root of the facial nerve in six mice. On an average, 3,433 (84.9%) of the total nerve fibers (4,046) were myelinated and 592 (14.6%) unmyelinated. The motor root consisted mostly of large myelinated fibers (large fiber group), but a part of the root consisted of small myelinated and unmyelinated fibers (small fiber group). The nerve fibers of the small fiber group appear to correspond with those of the intermediate nerve, and to pass through the motor root and enter the intermediate nerve near the geniculate ganglion.

Animals↗

PubMed1973