加藤 好光

After finding tonsil-like structures near the entrance of vagina of a laboratory shrew (Suncus murinus), which we subsequently designated as vaginal tonsils, we performed detailed immunohistochemical and developmental studies. The location of T and B cells in the vaginal tonsils differed from that in the palatine tonsils or that in the lymphoid nodes of other animals. The boundary between the germinal center region and the region encompassing follicular interfollicular tissue was not clear. B cells were widely distributed and very dense in the parenchyma, but they were scattered in the epithelial area (B cells were present in around 90% of the vaginal tonsil tissue). In contrast, T cells were scattered in the parenchyma and in the epithelial area (T cells were present in around 10% of the vaginal tonsil tissue). B cells were more prominent than T cells throughout the development of these structures and the epithelium was invaded by many immigrating cells. The size of the vaginal tonsils changed during postnatal development. Vaginal tonsils are structurally similar to other tonsils, and they may function to protect the vagina from infection.

The authors previously demonstrated that intracytoplasmic inclusion bodies (1-3 mu m) in the mouse locus coeruleus under light and electron microscopy are characteristically stained using the Holmes modified method. We reported that one inclusion body existed in almost all neurons of the locus coeruleus. The present study examined whether similar inclusion bodies are present in the Syrian hamster (weight, about 60 g). Paraffin sections stained with the modified Holmes' method displayed numerous small inclusion bodies in the cytoplasm of cells in the locus coeruleus. Epon sections (1 mu m thick) stained using toluidine blue were observed under light microscopy, and numerous small inclusion bodies were again observed. Under electron microscopy observation, inclusion bodies (< 1 mu m in diameter) predominantly comprised small granular materials, similar to those described by previous investigators. Although inclusion bodies were devoid of a limiting membrane, the relationship to cytoplasmic organelles was unclear. However, free and polyribosomes were occasionally noted in close proximity to inclusion bodies. Inclusion bodies may thus be formed from ribosomes. Intracytoplasmic inclusion bodies in the hamster locus coeruleus differed in appearance compared with inclusion bodies in the mouse locus coeruleus.

Anesthetized cats were injected with 2% Fast Blue and 0.5% Nuclear Yellow into the intermediate and deep layers of the left and right superior colliculus, respectively. In the right caudal part of the cerebellar fastigial nucleus (cFN), double-labeling was found in 38.5% of the neurons labeled with Fast Blue, and in 11.5% of the neurons labeled with Nuclear Yellow. In the left cFN, 52.2% of the neurons labeled with Fast Blue and 11.0% of the neurons labeled with Nuclear Yellow were double-labeled. The results suggest a role of bifurcating fastigial fibers in cerebellar visual control. (C) 2003 Elsevier Science B.V. All rights reserved.

媒体式および乾式製法により製造された無洗米の品質と炊飯特性について検討し, 以下のことが明らかとなった。<BR>(1) 無洗米は普通精白米に比してやや重量が少なく, 白度が高いことが特徴的であった。また, 製法の比較では乾式Cは媒体式A, Bに比して白度が低く, タンパク質, 脂肪の割合がやや多かった。<BR>(2) 洗米操作と洗液の濁度比較では無洗米は普通精白米より約2倍透明度が高かった。無洗米三種では媒体式A, Bは乾式Cに比して洗液の透明度が高く, 米粒への損傷が少なかった。<BR>(3) 無洗米三種は吸水率が高く, 特に媒体式A, Bは吸水速度も速く, 水温の影響も小さく, 吸水しやすい性質を示した。一方, 普通精白米は無洗米に比べて吸水が遅く, 特に, 低温での吸水率が低く, その要因として肌糠が無洗米に比べ十分に除去されていないためであることが示唆された。<BR>(4) 精白米粉のアミログラフによる粘度特性からは無洗米は普通精白米に比して糊化温度が低く, 最高粘度および最終粘度の経時的上昇が小さかった。また, 老化度では乾式Cは媒体式A, Bに比して低値を示した。<BR>(5) 光学顕微鏡による米飯の表面観察からは乾式で製造された無洗米の米飯は米飯表面においてズダンIV染色により脂質が濃く染色され, 肌糠等の残存がやや多いことが観察された。<BR>(6) 官能評価の結果からは無洗米米飯は, 炊飯直後では無洗化処理による差異すなわち, 媒体式および乾式製法による有意差はみられなかったが, 一日放置後では粘り, 口当たり, 総合評価の3項目で有意差が認められ冷めると食味が低く評価された。この要因としては加水量が低いことに由来していると推察された。

炊飯において硬水が飯の硬さに及ぼす影響およびその要因について研究した.米は初霜を用い, 炊き水には0.05M乳酸カルシウム溶液を用いて電気炊飯器で炊き, 飯粒の硬さの測定, 飯粒の膨潤, 胚乳細胞の大きさの測定を行い, 添加したカルシウムの分布を調べ, 普通飯粒との比較を行ってその原因を組織形態学的に明らかにしようとした.得られた結果は次の通りである.<BR>(1) テクスチュロメーター測定による飯粒の硬さは, 乳酸カルシウムを含む液で炊いたGa飯粒が, 普通飯粒よりも硬い.<BR>(2) Ga飯粒の膨潤度は普通飯粒と比較すると低い.<BR>(3) 顕微鏡下で観察・測定したGa飯の胚乳細胞の断面積は普通飯のそれより小さいことが認められた.<BR>(4) 普通飯粒の横断面の切片において, カルシウムイオンを蛍光色素オレゴングリーンで染色すると, 原料米に含有されているカルシウムは主に飯粒表層部の胚乳細胞壁に多く存在し, 飯粒中心部にむかっては少ない.カルシウムが存在している同部位にたんぱく質, ペクチン性物質が存在しているのがみられた.Ca飯粒では, 添加したカルシウムイオンが, たんぱく質, ペクチン性物質が多く存在する飯粒表層部の胚乳細胞壁に局在していた.特に背側部の胚乳細胞壁およびでんぷん複粒の周囲に局在し, この背側部の胚乳細胞は他の部分よりも膨潤が起きにくく, また, 普通飯よりも膨潤していないことが観察された.<BR>以上のことから硬水の炊飯過程における米粒の膨潤阻害の一因には, カルシウムイオンによる胚乳細胞内および胚乳細胞壁のたんぱく質とペクチン性物質の変化が関与していると推察できる.

The cat's lateralis medialis-suprageniculate nuclear complex (LM-Sg) in the thalamus receives input from various brain regions such as the superior colliculus, brain stem, and spinal cord, as well as from visual association cortex. In a previous study, we demonstrated that LM-Sg receives cholinergic fibers from the pedunculopontine tegmental nucleus (PPT) and that cholinergic terminals make synaptic contacts with the dendrites of glutamatergic projection neurons and of GABAergic interneurons (Hoshino et al., 1997). In this study, we investigate the distribution and the organization of PPT terminals by means of a combined anterograde tracer (biotinylated dextran amine, BDA) and immunohistochemical methods. When stained by acetylcholinesterase (AChE), the LM-Sg is not uniformly immunoreactive, but rather is patchily labeled and shows a streaming type of reactivity. The tissue content appears high in enzyme activity in AChE-positive zones and is much lighter in activity in AChE-negative zones. We compared the synaptic organization between AChE-positive and AChE-negative portions of the LM-Sg in separate groups of electron-microscopic material: four types of vesicle containing profiles (RS, RL, Fl, and PSD) as well as synaptic glomeruli were observed in this nucleus. Among these, the PSD profiles were observed more frequently in AChE-positive portions than in AChE-negative zones. Furthermore, the number of glomeruli was significantly higher in AChE-positive than in AChE-negative zones. Following the injection of BDA into PPT, labeled terminals within LM-Sg were rather more concentrated in the AChE-positive portion. Although the majority of PPT terminals made synaptic contacts with dendrites in the neuropil, a few terminals were involved in the synaptic glomeruli. The present results show that the synaptic organization is distinctly different between the AChE-positive and AChE-negative portions of LM-Sg. These results suggest that the AChE-positive portions of LM-Sg are relatively more involved in integrating information arising from a diverse set of inputs and processing that information within glomeruli in a complex manner than occurs in the AChE-negative portion of LM-Sg.

A double-labeling fluorescence microscopic study was performed on the mesencephalic and thalamic distribution of fastigial efferents. Anesthetized cats were injected with 2% fast blue into the suprageniculate nucleus and with 0.5% nuclear yellow into the superior colliculus. Analysis of serial sections through the cerebellar fastigial nucleus revealed that 25% of the neurons projecting to the superior colliculus and 10% of those projecting to the thalamus were double labeled. The results suggest that bifurcating fastigial fibers to the mesencephalon and to the visual thalamus may play a role in cerebellar visual control. (C) 2000 Elsevier Science B.V. All rights reserved.

Response properties of 252 single-units to visual, auditory, somatosensory and noxious stimulation were recorded by means of extracellular microelectrodes in the suprageniculate nucleus of anaesthetized, immobilized cats. Of the 141 units tested for modality properties the majority (n=113, 80.1%) was found unimodal in the sense that stimuli of exclusively one sensory modality were able to elicit an activation of the unit. Twenty-four (17.0%) cells were bimodal and four (2.8%) were trimodal (visual, somatosensory and auditory). The visual modality dominated the unimodal cells (n=74, 65.5%), while cells responsive to somatic stimulation (n=20, 17.6%), auditory stimulation (n=16, 14.1%) or noxious stimulation of the tooth pulp (n=3, 2.6%) were less Frequently encountered. Visual sensitivity dominated the multisensory cells, too. The visually responsive units were characterized by having a sensitivity to stimuli moving in a rather large, uniform receptive field that covered the contralateral lower quadrant, and encompassed a flanking area of about 20 degree width in both the upper contralateral and lower ipsilateral visual fields. Many cells (n=52, 47%) were sensitive to the direction of the stimulation and reacted to stimuli moving at a high velocity (20-200 deg/s). Most cells responded differently to stimuli of a variety of sizes. Somatosensory units reacted to stimuli presented over a wide area on the contralateral side of the body, thus showing no sign of somatotopic organization. The auditory sensitivity fell within a wide range of acoustic stimuli in extremely large auditory receptive fields. The physiological properties of suprageniculate nucleus cells strongly resemble the sensory properties of cells found along the ventral bank of the anterior ectosylvian sulcus and the deeper layers of the superior colliculus. Our results provide further support for the notion of a separate tecto-suprageniculate-anterior ectosylvian sulcus/insular pathway that takes part in the processing of multimodal signals important for various types of sensory related behaviours. (C) 1997 IBRO.

Physiological properties of single units were investigated in the suprageniculate nucleus (SG) and in the cerebral cortex along the anterior ectosylvian sulcus (AES), including the insular cortex. The recording was performed with the aid of carbon-filled glass micropipetts in barbiturate-anesthetized cats. The main findings of the study can be summarized as follows. 1. The physiological properties of the cells in the suprageniculate nucleus and in the AES/insular cortex exhibited striking similarities in a series of aspects: (a) The frequencies of occurrence of uni-, bi- and trimodal cells were similar. (b) The majority of the unimodal cells (75% in the AES/insular region and 65% in the SG) has visual sensitivity in both structures. The bimodal and trimodal cells were also dominated by visual sensitivity. (c) The somatosensory and auditory modalities were similarly present in both structures, although less frequently than the visual one. (d) No systematic topological organization was found in either structure. (e) The visual, somatosensory and auditory receptive fields were uniform and covered a fairly large proportion of the personal space. 2. Statistical comparison of some physiological properties of cells situated deep in the AES with those of cells in the insular cortex revealed differences as follows: (a) The insular cortex contained significantly more bi- and trimodal cells than the sulcal areas. (b) Cells in the insular cortex preferred significantly lower stimulus velocities and larger stimuli than cells in the depths of the AES. These results seem to support the notion of a suprageniculate-AES/insular thalamo-cortical multisensory entity. Additionally, the physiological differences between the sulcal AES cortex and gyral insula are in agreement with the morphological differences found earlier in the afferentation of these areas (Norita et al., 1986, 1991).

A wheat germ-agglutinated horseradish peroxidase (WGA-HRP) tracing technique was used to label the cell bodies of neurons in the superior colliculus that send projections into the visually sensitive region of the suprageniculate nucleus (Sg) in the feline thalamus. After determination of the position of the Sg by detecting characteristic single-unit responses to moving visual stimuli, WGA-HRP was injected into the Sg in five pentobarbital-anesthetized cats. The animals were than sacrificed, and serial frozen sections of the midbrain were processed for the demonstration of peroxidase activity. A total of 2,736 WGA-HRP-stained neurons were located within the ipsilateral superior colliculus (SC), and a few labeled cells were consistently found bilaterally in the external nuclei of the inferior colliculus. In each cat, a small but significant fraction of the labeled cells were encountered contralateral to the injection. Medial SC neurons tended to project to the posterior Sg, and lateral SC neurons tended to project to more rostral Sg. However, labeled cells were distributed homogeneously along the rostrocaudal extent of the SC, indicating the absence of a well defined topographic relationship. Nor was the Sg injection site location related to the laminar distribution of SC projection neurons. In all cases, the majority of the labeled cells were found in layer IV (49.0%), with fewer cells in layers III (17.5%), layer V (20.0%), and layer VI (11.8%). No labeled cells were located in layer I, although a few were located in the deep part of layer II. Five types of SC projection cells were distinguished morphologically. Of the 258 labeled cells that could be characterized, 25% were stellate cells, 25% vertical cells, 20% granular cells, 17% triangular cells, and 12% horizontal cells. The average diameter of 226 cells ranged between 8 and 47 mu m. We conclude that a mixed population of SC cells projects to the Sg; the morphological heterogeneity and the distribution of these cells suggests that several functionally different pathways may be involved in the colliculothalamic pathway and in the processing of visual input in the SC. (C) 1995 Wiley-Liss, Inc.

Following WGA-HRP injection into the right suprageniculate nucleus of the cat brain, retrogradely-labeled neurons were found not only in the ipsilateral, but also in the contralateral superior colliculi. After WGA-HRP injection into the unilateral superior colliculus, anterogradely-labeled axon terminals were observed in the bilateral suprageniculate nuclei, and electron microscopic examination revealed that these were large terminals which made asymmetric synaptic contacts with dendrites. When a different kind of fluorescent tracer was injected into each suprageniculate nucleus (Fast blue and Nuclear yellow), double-labeled neurons were observed in the rostral and middle portions of both superior colliculi. These results suggest that there are direct bilateral projections from the superior colliculus to the suprageniculate nuclei, and that some of these projections originate from branching colliculo-suprageniculate axons.

Axonal transport of WGA-HRP injected into (1) the suprageniculate nucleus or (2) the fastigial nucleus, was investigated. Retrogradely labeled neurons were found in the caudal part of the bilateral fastigial nucleus following injection 1, and anterograde labeled axon terminals were observed in the bilateral suprageniculate nucleus following injection 2. Electron microscopic observations of these terminals revealed that they were large terminals making asymmetric synaptic contacts with dendrites. These results suggest that some neurons in the fastigial nucleus send their axons to the suprageniculate nucleus.

Extracellular recordings with carbon fiber-filled microelectrodes were used to identify the visually responsive area within the insular cortex (referred to hereafter as the insular visual area, IVA) of anaesthetized cats. Broadly speaking, IVA comprises the cortex surrounding the anterior ectosylvian sulcus (AEs) along its ventral bank and the major portion of the anterior sylvian gyrus. Visually sensitive cells were recorded along the whole length of the AEs. In the same animals, the afferent connections of IVA were studied through the use of the retrograde tracers wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) and fluorescent Diamindino yellow (DY), in combination with standard electrophysiological stimulation and recording techniques. The results indicate that: (1) the IVA receives a wide variety of telencephalic inputs, not only from visual, sensorimotor, auditory, limbic and association cortical areas, and from the claustrum, amygdala and basal nucleus of Meynert, as well, but also from the diencephalic projections arising mainly from the lateralis medialis-suprage niculate nuclear complex (LM-Sg) and the ventral medial nucleus (VM). (2) The gyral part of IVA (gIVA) receives afferents mainly from the lateral part of the lateral suprasylvian visual area (LS) throughout almost its entire length, as well as from area 20, the posterior suprasylvian sulcal area (PS), the frontal eye fields, areas 6 and 36, and almost the whole length of the cortical area lying along the anterior ectosylvian sulcus (AEs). (3) By contrast with (2), the sulcal part of IVA (aIVA) which corresponds to the anterior part of the anterior ectosylvian visual area (AEV) of Norita et al. ('86), receives cortical projections mainly from the lateral and medial parts of the anterior half of LS, area 20, PS, the frontal eye fields, area 36, and most parts of the cortical area extending along the AEs. (4) Subcortically, IVA receives thalamic afferents mainly from VM and LM-Sg. The connections between IVA and LM-Sg are organized topographically, with the more anterior part of IVA being related to the more ventral portion of LM-Sg, and with sIVA being related chiefly to the mid-portions of LM-Sg. These results thus suggest that IVA may function as an integrative centre among structures belonging to the extrageniculostriate system, the sensorimotor system, as well as to the limbic system. Furthermore, our electrophysiological and anatomical findings, together with previous reports concerning AEV, suggest that the posterior part of AEV (AEV proper) is dinstinctive from gIVA, and that the sIVA apparently serves as a transitional region between AEV and gIVA.