This investigation was made on sequential changes in the tongue caused by unilateral transection of the hypoglossal nerve in the rat. These changes were examined on the basis of gross inspection of the lingual dorsal surface, histological aspects of the intrinsic muscle and interstitial tissues, morphological changes in the capillary loops of the filiform papillae utilizing plastic microcorrosion casts, and blood flux and number of erythrocytes in the lingual dorsum as determined by laser Doppler flowmetry. The period of examination following denervation of the hypoglossal nerve was divided into 3-5 days,1,2-3,4-5,6-7 and 66 weeks. The initial sign of histological change was an edematous change that later developed to atrophic change of the muscular element. This pathological change caused a change in volume on the lesion side of the tongue and finally formed a depression on the dorsal surface and a scallop-like lateral margin. Four to five weeks after denervation, the lesion half swelled, and its lingual apex elongated forward with a coving of the lingual median groove. The filiform papillae showed decreased keratinization, and interpapillary intervals were somewhat widened. Capillary loops in the papillae began to change, showing slight twistings at the tips of loops. Additionally, bulging, coiling and tortuosity were observed on both crura. The loops showed more complicated transformation, and little recovery was observed even 66 weeks after denervation. Blood flux in the dorsal mucosa decreased very slowly after a slight increase. This process seemed to be in proportion to the transformational complexity of the capillary loops in the filiform papillae. In conclusion, unilateral transection of the hypogrossal nerve, which is composed almost entirely of efferent neurons, caused edema and atrophic change in the intrinsic lingual muscle fibers with interstitial fibrosis in the lesion half of the tongue. Capillary loops in the filiform papillae were transformed markedly and successively by transection of the hypoglossal vasomotor neuron together with a slight decrease in blood flow in the dorsal mucosa. None of these changes recovered even at 66 weeks after transection.

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The three-dimensional architecture of collagen fibrils in the mouse testicular capsule was studied after digestion of cellular and some extracellular elements by 10% NaOH. In the tunica vaginalis, the collagen fibrils were interwoven in an irregular and complex pattern. The tunica albuginea consisted of successively stacked lamellae of collagen bundles, which were arranged parallel to the testicular surface and ran across their neighbors at almost right angles. This arrangement of collagen fibrils appears to be effective in giving the testis its rigidity. Further, the collagen bundles in the tunica albuginea showed more or less undulating courses. It is suggested that the bundles undergo alteration from straight to undulate, to permit contraction of the testicular capsule.

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Elastic system fibers (ESFs), i. e., microfibrils (putative oxytalan fibers), elaunin and elastic (true elastin) fibers, in the rat mandibular joint were studied mainly using scanning electron microscopy (SEM) and light microscopy (LM) with the aid of image processing. The present quantitative analysis using LM showed that the articular disc and capsule, which are the sites that receive physical compressive force during mastication, contained more ESFs than the articular cartilage of the mandibular joint. In addition, oxytalan fibers were the principal ESFs in all the articular components (capsule, articular disc, supraosseous layer of articular surfaces and articular cartilage). Subsequently, ESFs in the articular disc, which contained more thick ESFs, were closely examined by SEM using both collagen- and elastin-digestion methods. SEM showed networks of microfibrils beneath the articular surfaces (superior and inferior layers) in the thin central portion of the articular disc; the principal microfibrils ran at nearly right angles to the collagen fibers. The microfibrils were cemented with amorphous elastin, thickened and shifted towards interconnecting oblique fibers and many main ESF trunks, which were oriented in the direction of the layered wavy collagen fibers and parallel to the direction of applied force, to sustain the mechanical force. From the superior and inferior layers, the main ESFs shisfted towards the middle portion of the disc, transitional zone (synovial osteochondral junction) and the other articular components, showing no specific directivity. Transmission mission electron microscopy revealed that the thick main ESFs in the elastic network were elaunin fibers. The present study indicated that ESFs unite, branch and therefore construct an extensive and complicated protective stretchable network, which is interposed with the less tensible collagen network in the mandibular articular disc.

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Standardized photographs (lateral and basal view) of fetal mandibles (n=80) were taken. Outline segments (from gnathion to condylion, on the coronoid process and from infradentale to gnathion in lateral view; and on the inferior margin in basal view) were analyzed into sine curves, according to Fourier series. Using the calculated Fourier coefficients, we statistically examined how mandibular shape changed with fetal growth. Materials were classified into four groups on the basis of the body length (BL): 100≤BL <200mm(BL1, n=20); 200≤BL <300mm (BL2, n=20); 300≤BL <400mm (BL3, n=20); and 400≤BL≤500mm (BL,4=20). Statistical analyses were all done on these stature groups.
On the outline from gnathion to condylion, the constant and the first term phase showed statistically greater values in BL4 than in the other groups, as assessed by t-test. The first term phase for the coronoid process signficantly decreased with increments in stature in the canonical disciminant analysis. On the outline from infradentale to gnathion, although the cumulative contributions of the first two terms were constant (about 85%) in all four groups, the relative contributions with growing stature decreased in the first term and increased in the second term. The mean of the phase in the first term indicated slightly more than -90 degrees in BL1, and was less than -90 degrees in BL2 to BL4. The averages of the second term phases presented little change from BL1 to BL3, and were close to -100 degrees. From the canonical discriminant analysis, the constant was great and the first term amplitude was small in BL1 and BL4, and the constant was small and the first term amplitude was great in BL2 and BL3. Also, the second term amplitude in BL4 indicated a significantly bigger volume than in BL3. The constant for the inferior margin manifested statistically significant increments in BL2 to BL4, as assessed by t-test.
We interpret the results as follows:
1. On the outline from gnathion to condylion, anteroinferior shift occurs in BL4, resulting in an acute gonial angle. The change of angle during the prenatal period precedes the postnatal findings that bring about a progressive decrease in the gonial angle.
2. The tip of the coronoid process indicates a forward shift with increasing fetal body stature. The cause of this anterior movement probably derives from forward traction of the temporal muscles.
3. The shape from alveolus to mentum changes from a flat waveform in BL1, to two bumps in BL2 to BL3 with the lower bump on the alveolar side and the taller bump on the mental side, and ends up in an anterior prominence and sharpness of those two bumps in BL4. One may infer that the mental protuberance begins to form in the fetal mandible, though it is only slightly.
4. The outline on the inferior margin protrudes forward in BL4.

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Injecting the retrograde fluorescent neuronal tracer fluoro-gold into the dorsal nucleus of the lateral geniculate body (dLGN), the olivary pretectal nucleus (OPN), and the superior colliculus (SC) revealed the existence of some ganglion cells (RGCs) scattered outside the temporoventral crescent of the ipsilateral retina in the adult albino rats. We studied the projection patterns, topographic distribution, number, and the soma size of these aberrant RGCs in 12 adult albino rats. We estimated a mean of 50 aberrant cells projecting to dLGN. Their soma size ranged from 40.6 to 211.0μm², with an average of 108.6μm². The soma size of the 45.5 aberrant cells projecting to the OPN ranged from 41.5 to 312.5μm², with an average of 147.2μm². The SC received projection from 38.3 aberrant cells whose soma size ranged from 42.0 to 315.1μm², with an average of 120.7μm². These cells were almost. equally distributed between the central and peripheral portions of the ipsilateral nasal retina. The mean cell count of the SC-projecting population was significantly lower than those of the other 2 groups. The mean soma size of the OPN-projecting aberrant cells was larger, and their soma size histogram was significantly different from those of the other 2 groups, whose histograms were almost alike. Though their physiological role in processing visual information is not fully understood, the aberrant RGCs might project their axons to - in addition to the dLGN, OPN, and SC - other visual centers.

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The microvascular architecture of the fungiform, vallate and foliate papillae was investigated under scanning electron microscope in man, common squirrel monkeys, common marmosets, common tree shrews (primates), large Japanese moles and dwarf shrews (insectivores) utilizing microvascular corrosion casts. The fungiform papilla of the lingual apex in man was supplied by an intrapapillary capillary network with a globular pattern. It was composed of 10-15capillary loops in a circular arrangement and 5-7 thick capillaries in the center. The fungiform papilla of the lingual body was supplied by a dense capillary network on the top and lateral surfaces. That in other primates was supplied by a cylindrical capillary network and loop formation was seen on the top surface. That in insectivores was supplied by a thin cylindrical network with coarse meshes, at the tips of which were observed 2 or 3 capillary rings in the mole and only one in the dwarf shrew. The vallate papilla in primates was supplied by an intrapapillary capillary network with a globular pattern, and showed irregularly tortuous capillary loops on its top surface. The vallum was supplied by a capillary network in man and usually one or two rows of loops arranged in a circle in other primates. The vallate papilla in insectivores was supplied by a doughnut-like capillary network with a recess on the top surface, and an indistinctly low vallum by a low undulating network. The foliate papillae were most developed in man, and each lobule was supplied by capillaries passing longitudinal to it and capillary loops in 5-10 regular rows on the top, but 3-5 rudimentary lobules in the squirrel monkey and marmoset. In the two species, each lobule was supplied by one arteriole, one venule and a coarse capillary network continuing from the interpapillary network. No foliate papilla was observed, but large conical papillae were noted in the tree shrew and insectivores. In conclusion, the intrapapillary vasculature appeared most complicated in man, simplified in the squirrel monkey and marmoset, and was much more simplified in the insectivores, where it was quite different from that in the primates. The pattern of the intrapapillary vasculature in the tree shrew was transitional between primates and insectivores.

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