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Biomedical subjects

Y Takei

Publications and source records attributed to Y Takei.

At least 379 records · Page 21Linked to original sources
PubMed1980

Ultrastructural study of the human neurohypophysis. II. Cellular elements of neural parenchyma, the pituicytes.

The pars nervosa of the neurohypophysis from 12 patients undergoing hypophysectomy for palliative treatment of advanced carcinoma was studied electron microscopically. Special attention was given to the cellular elements, the pituicytes. Five different classes of pituicytes, with various transitional forms, were elucidated based on their ultrastructural characteristics: (1) The most common type, referred to as "major pituicytes", is reminiscent of astrocytes. (2) "Dark pituicytes" are thought to represent different functional stages of the "major pituicytes". (3) "Ependymal pituicytes" are believed to provide ultrastructural evidence that human pituicytes are phylogenetically derived from ependymal cells. (4) "Oncocytic pituicytes" were observed in all cases and are of unknown significane. (5) The ultrastructural features of "granular pituicytes" suggest the existence of an active uptake and catabolism of extracellular material by pituicytes, probably through "ultraphagocytosis" or "endocytosis". These five classes of pituicytes are considered to represent different functional forms of one cell line that originates phylogenetically from the ependyma.

Cell Nucleus↗
PubMed1980

Acid phosphatase in eyes with pseudoexfoliation.

We studied the activity of acid phosphatase in the anterior segment of the eye with pseudoexfoliation histochemically and biochemically. Light and electron microscopic histochemistry revealed lead precipitates indicating acid phosphatase activity in pseudoexfoliative materials. Biochemical assay for acid phosphatase was significantly higher in the aqueous humor of eyes with pseudoexfoliation than in that of cataractous eyes without pseudoexfoliation.

Acid Phosphatase↗
PubMed1980

Benign hemangioendothelioma involving the central nervous system: "strawberry nevus" of the neuraxis.

Benign hemangioendothelioma is rarely included in discussions of vascular neoplasms involving the central nervous system, whereas it is a well-defined entity outside the neuraxis. We present four cases of benign hemangioendothelioma, including an infantile hemangioendothelioma with venous drainage into the transverse dural sinus, an intracranial hemangioendothelioma adherent to the falx cerebri, a spinal epidural hemangioendothelioma causing spinal cord compression, and a parasellar hemangioendothelioma. Although hemangioendothelioma resembles hemangioblastoma in some ways, it is a distinct entity differing from the other vascular lesions involving the central nervous system.

Adult↗
PubMed1980

Cutaneous calcinosis in localized discoid lupus erythematosus.

Cutaneous calcinosis is reported in the lesions of a woman with long-standing discoid lupus erythematosus. Calcium deposits were found in the middle and deep parts of the dermis surrounded by homogeneous collagen staining positively with Alcian blue solution. In contrast to the relative frequency of this event in patients with scleroderma or dermatomyositis, calcinosis cutis occurs very rarely in lupus erythematosus. To the best of our knowledge, this is the first report of calcinosis cutis in discoid lupus erythematosus.

Adult↗
PubMed1979

Involvement of catecholaminergic nerve fibers in angiotensin II-induced drinking in the Japanese quail, Coturnix coturnix japonica.

Monamine distribution in a septohypothalamic area was investigated in the Japanese quail using a histochemical fluorescence method. This area includes the subfornical organ (SFO) and the preoptic area (POA) which are inferred dipsogenic receptor sites for angiotensin II (AII) in the Japanese quail. Nerve fibers showing yellow-green fluorescence were found between the POA and the SFO. Thwy traversed from the POA to the SFO, and some fibers seemed to terminate on the neurons in the SFO. After a low dose of reserpine, a considerable number of fluorescent perikarya were found in the POA. These fibers and perikarya appeared to be of primary catecholamine judging from the fluorescence color. Following transection of these fibers, fluorescence disappeared from the fibers located on the SFO side of the transection plane, while it became a little more intense on the POA side. After transection, microinjection of AII into the POA was no longer effective in induction of drinking. On the other hand, sham operation or transection in areas other than between the POA and the SFO produced only minute changes in those fluorescent fibers and had little effect on the dipsogenic potency of AII injected into the POA. These results suggest that information of AII perceived at the POA is transferred to the SFO via those primary catecholamine-containing nerve fibers, which effect induced drinking.

Angiotensin II↗
PubMed1979

Intraventricular fiberscopic observations in adult hydrocephalic patients.

A flexible ventriculofiberscope was used to diagnose intraventricular pathological conditions in eight adult hydrocephalic patients. In each case the entire procedure was recorded on videotape for documentation, review, and teaching. Four representative cases are presented to illustrate the use and value of this technique.

Adult↗
PubMed1979

Abdominal metastases of primary intracranial yolk sac tumors through ventriculoperitoneal shunts: report of three cases.

Three cases of rare primary intracranial yolk sac tumor are reported. Two cases had a pineal location, whereas the third presented as a suprasellar mass. After the placement of ventriculoperitoneal shunts for relief of hydrocephalus, all of the patients developed metastases restricted to the peritoneum, as demonstrated by autopsy in one patient (Case 1) and clinical and radiographic evidence in two patients (Cases 2 and 3). The peritoneal metastases were directly associated with the death of one patient, but were successfully treated with chemotherapy in another patient, who is still alive more than 2.5 years after initial presentation. The value of ascitic fluid cytology and alpha-fetoprotein determination in the diagnosis of this complication was demonstrated in one patient. These cases emphasize the need for awareness of this mode of metastasis and its potentially lethal effect.

Adult↗
PubMed1978

Surface fine structure of the subfornical organ in the Japanese quail, Coturnix coturnix japonica.

The surface ultrastructure of the subfornical organ (SFO) was investigated in the Japanese quail. The SFO consists of a body and a stalk. The body of the SFO can be divided into rostral and caudal parts. On the rostral part, each ependymal cell possesses a short central solitary cilium; clustered cilia are also occasionally seen. Microvilli are abundant. On the caudal part, cells with a solitary cilium are fewer in number, and clustered cilia are rarely found. Microvilli are not as abundant as on the rostral part. In addition, large bulbous protrusions, tufts of small protrusions, deep funnel-shaped hollows, small pinocytotic invaginations and possible cerebrospinal fluid-contacting axons are sporadically observed on the surface of various regions of the body. Each ependymal cell of the stalk has a wide apical surface. A central solitary cilium, microvilli and other structures are observed more rarely on the stalk than on the body, while clustered cilia are not seen on the stalk. These structures are compared with those of the mammalian SFO and further discussed in relation to the possible dipsogenic receptor function for angiotensin II.

Animals↗
PubMed1978

Parenchymal fine structure of the subfornical organ in the Japanese quail, Coturnix coturnix japonica.

The parenchyma of the subfornical organ (SFO) of the Japanese quail was studied by light and electron microscopy. The SFO consists of ependymal, intermediate, and basal (perimeningeal) layers. In the intermediate layer, neurons, glial cells, and their processes are found. Axons containing dense core granules approximately 80 nm in diameter are numerous, some of which make synaptic contact with the neuronal perikarya or dendrites. Synaptic vesicles in some axons contain a dense dot in the interior after treatment with 5-hydroxydopamine. The activity of the SFO, which is probably concerned with elicitation of drinking by angiotensin II, may be regulated at least partly by afferent monoaminergic axons. Capillaries with a non-fenestrated endothelium are occasionally found in the parenchyma. The basal layer is occupied by glial processes abutting on the digitating layer of perivascular connective tissue of meningeal vessels. The endothelium of these vessels is occasionally fenestrated. Trypan blue injected systemically accumulated in the SFO, but not in the deeper areas of the brain. The absence of a blood-brain barrier is suggested in the SFO.

Animals↗
PubMed1978

Mixed mesenchymal and neuroectodermal tumor of the cerebellum.

An unusual cerebellar tumor composed of mixed mesenchymal and neuroectodermal elements in a 44 year old man is reported. The mesenchymal element is well-differentiated adipose tissue, whereas the neuroectodermal components exhibit a variety of medulloblastomatous, astrocytomatous, oligodendrogliomatous and ependymomatous areas. A possible origin of such unusual mixed neoplasms is briefly discussed.

Adipose Tissue↗
PubMed1978

Electron-microscopic study of pseudo-exfoliation of the lens capsule.

The lens, iris, and ciliary body from the eyes of patients with glaucoma with cataract were examined via electron microscopy, and the following results obtained. 1. Zonular bundles were encrusted with accumulations of pseudoexfoliative (PE) materials and fragmented zonular fibrils, especially on their lateral aspects. 2. PE materials ranged from 300 to 400 A in width, consisting of several subunits about 100 A wide. 3. Pigment epithelial cells of the iris and nonpigmented epithelial cells of the ciliary process occasionally contained many phagosomes engulfing pigment granules. 4. Near the ciliary process, degenerating zonular bundles were mostly replaced with PE materials and fragmented zonular fibrils, and a gradual transition was observed between them. From the above findings, it is probable that PE material might be mainly composed of degenerated zonular fibrils, which are presumed to be digested with lysosomal enzymes.

Aged↗
PubMed1977

The role of the subfornical organ in drinking induced by angiotension in the Japanese quail, Coturnix coturnix japonica.

Synthetic 5-valine angiotensin II (AII) induced copious drinking when applied directly to the the subfornical organ (SFO) in the Japanese quail. Reliable response was obtained with as little as 1 ng of AII. The amount of water intake increased dose-dependently from 5 ng to 1 microgram. A latent period of 73.0 +/- 11.0 seconds at 100 ng was noted. The electrical destruction of the SFO significantly reduced the amount of water intake induced by both intravenous and intracranial AII injections. The decrease was proportional to the extent of the SFO lesion. It is conceivable, therefore, that the SFO plays an important role in elicitation of drinking by AII in birds as suggested in mammals.

Angiotensin II↗
PubMed1977

Glycogen and development of outer segment in monkey fetuses.

Glycogen particles in developing photoreceptors were investigated in monkey fetuses of various ages under the electron microscope. Glycogen particles were first observed at 100 gestational days in primitive outer segment sacs and inner segments, prior to the appearance of tubulous disc membranes in the peripheral region of outer segment sacs. The particles gradually increased in number as the outer segments differentiated, decreased in number by 143 gestational days, and finally disappeared in the photoreceptors by 160 gestational days, when the photoreceptors were almost formed as in adult monkeys. It is therefore postulated that glycogen particles seen in the photoreceptors are closely concerned with the rapid differentiation of outer segments for a short duration in the developing stages.

Animals↗
PubMed1977

Electron microscopic studies on zonule. Its origin and fibroblast.

Rabbit fetuses (14, 16, 17, 18, 20, 22, and 24 days in utero) were examined with an electron microscope, and the following results were obtained: 1. At the equatorial region of the lens, developing endothelium of the tunica vasculosa lentis was very similar in morphology to typical fibroblast. 2. Much debris of amorphous material was observed around the endothelium and fibroblast, but in general, zonule-like fine fibrils were seen near the former, whereas short collagen fibrils were observed around the latter amid amorphous material. 3. Topographically, fibroblasts lay apart from the lens equator, and few fibroblasts migrated into the posterior portion. 4. From the above data it was postulated that debris around the tunica vasculosa lentis in the vicinity of the lens equator was presumably the precursor of zonular fibrils and that fibroblasts had almost no relation to zonular formation.

Animals↗
PubMed1977

Leber's congenital amaurosis.

An early stage of Leber's congenital amaurosis, characterized by white spots or lines in the fundus, occurred in two children. Light microscopic examination of eyes obtained from one child, a 16-month-old Japanese girl, revealed subretinal deposits corresponding to the white spots and lines in the fundus deposits. Light and electron microscopic examination of the eye showed distinctive changes in the outer retinal layers and choroid, while the inner retinal layers were nearly normal. Characteristic early lesions of congenital amaurosis appeared to be produced by deposits consisting of loose outer segments and apical processes of the pigmental epithelial cell and macrophages. Undifferentiation in the nuclei of the photoreceptor cell, the inner segment, the pigment epithelial cell, and the choriocapillaris were likely characteristics of the early changes of congenital amaurosis.

Blindness↗