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Biomedical subjects

Y Sano

Publications and source records attributed to Y Sano.

At least 253 records · Page 14Linked to original sources

Dynamic mechanism of the self-assembly process of tobacco mosaic virus protein studied by rapid temperature-jump small-angle X-ray scattering using synchrotron radiation.

The self-assembly process of tobacco mosaic virus protein (TMVP) was observed by rapid temperature-jump time-resolved solution X-ray small-angle scattering using synchrotron radiation. The temperature-jump device used for the X-ray measurements is rapid enough to cope with even the fastest-assembling process of TMVP, and accumulates data of reasonable signal-to-noise ratios with a minimum total counting time of 7.5 seconds. The measurements suggested that the 20 S disk of TMVP polymerized to stacked disks (short rods). The time to complete stacking varied from approximately 25 seconds to approximately 1200 seconds, depending on the solution condition and magnitude of the temperature gap. Higher protein concentration, ionic strength and temperature favoured faster association. The results were analysed in terms of a set of kinetic equations that describe the two-stage aggregation of TMVP with an equilibrium constant K1, and two rate constants k+2 and k-2 for association and dissociation of disks, respectively. The consistency of the analysis suggests that the TMVP assembly proceeds in two steps of: (1) the aggregation of A-proteins into double-layered disks; and (2) the stacking of double-layered disks. The kinetic analysis indicated that the stacking belongs to the lowest range of protein-protein interaction system.

Capsid Proteins↗

Rearrangement of serotonin-immunoreactive fibers in the denervated rat suprachiasmatic nucleus after transplantation of fetal raphe tissue.

Pieces of fetal midbrain raphe tissue were transplanted into the third ventricle or the ventral hypothalamic region near the suprachiasmatic nucleus (SCN) of adult host rats that had previously been denervated by treatment with 5,6-dihydroxytryptamine. The ability of grafted serotonin neurons to reinnervate the SCN in the host rats was studied by means of immunohistochemistry 1 and 3 months after transplantation. In both the intraventricular and intraparenchymal transplant experiments, reinnervation by outgrowing serotonin fibers was observed in the hypothalamus of host rats at 1 and 3 months after surgery. At both survival periods, there was no abundant arborization of serotonin fibers in the SCN, while the preoptic and periventricular areas of the host rats displayed a pattern of serotonergic innervation resembling that in normal (untreated) rats. It is suggested that within the SCN the regenerating serotonin fibers may be exposed to an inhibitory environment.

Animals↗

Quantitative in situ hybridization to measure single-cell changes in vasopressin and oxytocin mRNA levels after osmotic stimulation.

1. The measurement of cellular mRNA content by quantitative in situ hybridization is a valuable approach to the study of gene expression in brain since this tissue exhibits a high degree of phenotypic heterogeneity. 2. The cellular content of vasopressin and oxytocin mRNA in hypothalamo-neurohypophysial system neurons was altered by maintaining rats for 24 hr on 2% sodium chloride water. 3. Statistical and graphical techniques were then used to analyze cell by cell how mRNA levels were altered as a result of osmotic stimulation. We propose that the negative binomial probability distribution is a suitable model to describe how mRNA content varies across a defined cell population. For both measures of oxytocin and vasopressin mRNA levels, maximum-likelihood estimation indicated that this model adequately described empirical findings obtained from rats drinking tap water or salt water. 4. Both graphical and statistical analyses suggested how the defined neural system responds to osmotic stimulation: mRNA content was altered as a multiplicative function of "initial state." The utility and limitations of the quantitative approach are discussed.

Animals↗

The genic nature of gamete eliminator in rice.

The two cultivated rice species, Oryza sativa and Oryza glaberrima, are morphologically alike but are reproductively isolated from each other by hybrid sterility. The hybrid is male sterile but partially female fertile. Backcross experiments were conducted to introduce an alien factor controlling hybrid sterility from O. glaberrima (W025) into O. sativa (T65wx) and examine the genetic basis. An extracted sterility factor, closely linked to the wx locus, induced gametic abortion due to allelic interaction and was tentatively designated as S(t). The segregation patterns for infertility was explained by assuming that W025 and T65wx carried S(t) and S(t)a, respectively, and gametes with S(t)a aborted only in the heterozygote (S(t)/S(t)a) although the elimination of female gametes was incomplete. Thus, S(t) seemed to be intermediate between a gamete eliminator and pollen killer. However, S(t) was proven to be likely the same as S1 which was formerly reported as gamete eliminator in a different genetic background of O. sativa. In addition, a chromosomal segment containing S1 (or S(t] caused a marked suppression of crossing over around it, suggesting the presence of an inversion. Further, female transmission of S1a increased as the segment containing S1 became small by recombination. After S1 was further purified by successive backcrosses up to the BC15 generation, it became pollen killer. The present results give evidence that a profound sterility gene such as gamete eliminator can be made from accumulation of pollen killer and its modifier(s) when pollen killer and modifier(s) are linked, they behave as a gene complex in the hybrid.

Alleles↗

The role of inhibin in women with polycystic ovary syndrome (PCOS).

Human follicular fluids from normal women and from women with polycystic ovary syndrome (PCOS) were collected at various stages of the menstrual cycle, and inhibin and steroid contents were determined by rat anterior pituitary cell monolayer bioassay system and specific RIAs, respectively. Inhibin contents in viable follicles were significantly higher than those in atretic and in cystic follicles. Preovulatory and luteal phase follicles had lower inhibin levels than viable follicles in normal women. A significant inverse correlation was found between inhibin contents and androstenedione to estrogen ratios. The inhibin contents in PCOS follicles were not significantly different from those of viable follicles of normal women at the early follicular phase, but they were significantly higher than in atretic follicles. Since PCOS ovaries often contain more antral follicles than normal ovaries, it could be that this potential source of inhibin may be greater than in normal ovaries. Furthermore, 9 out of 10 follicles in any ovary of normal women are atretic and contribute less inhibin production, whereas PCOS ovaries contain many follicles capable of secreting considerable amounts of inhibin. Therefore, PCOS ovaries totally may secrete more inhibin than normal ovaries. This higher potency of PCOS ovaries to secrete inhibin along with higher serum estrogen levels may be responsible for the disparity between basal LH and FSH levels in PCOS.

Animals↗

Simultaneous occurrence of calcification and amyloid deposit in pilomatricoma.

Amyloid deposition was encountered in 10 of 16 samples of pilomatricoma, indicating that the deposition of amyloid is nearly as common as calcification in pilomatricoma. In addition, a simultaneous occurrence of calcification and amyloid deposit in pilomatricoma was recognized in 9 of 16 samples. The calcification and the deposition of amyloid developed topographically in the same area within the shadow cell masses. Such an area was revealed as moderately basophilic, amorphous, or hyalinized by H&E staining. Electron microscopy revealed spotty calcium deposits in amyloid. No light chains of human immunoglobulin were detected in the amyloid-deposited area. Amyloid in this tumour may facilitate calcification or serve as a matrix for subsequent calcification.

Adolescent↗

[A study on display and accuracy of occlusal contacts by means of T-Scan System].

The various methods were introduced in the daily prosthodontic field evaluating occlusal contacts for diagnosis and analysis. Maness in 1987 developed the T-Scan system, which is considered as a new computerized device capable to interpret occlusal contacts information quantitatively. The system is composed of a sensor, sensor frame, handle, cable and system unit. Record and analysis mode made possible the occlusal contacts in three ways, such as the balance plot, the time display and comparison screen. However, accuracy and reproducibility of occlusal marking through this system is still uncertain. Therefore, this preliminary study was conducted on four specific points loaded on a sensor by application of the weight of 0.1 kg through 10 kg. The following results were obtained 1. There exists certain non-sensible areas caused by its constructional feature. 2. The most sensible area can be measured from 0.1 Kg to 2.1 Kg, and therefore, this device is more suitable for recording within lower loadings. 3. Although the system has a certain disadvantage of reproducibility, this contributes to attain diagnosis and treatment of occlusal contacts for a quantitative evaluation.

Dental Occlusion↗

[Dissolution of silver and copper from Ag-Cu binary alloys under dynamic conditions].

Ag-Cu binary alloys containing 5-30% copper were subjected to dynamic extraction at 200 rpm and 37 degrees C to simulate the functional movement in the oral environment. Extraction was carried out in Eagle's minimum essential medium every two weeks for 18 weeks. The corrosion products were examined by the separation of extracts with a 0.22 micron filter. Significant dissolution of copper occurred with increasing copper content, but the increase in silver dissolution was slight. The amount of copper in the filtrate was the same as that in the extract, but no silver was detected in the filtrate. Therefore, dynamic extraction accelerated the dissolution of copper from the Ag-Cu binary alloys and thus lowered the corrosion resistance.

Copper↗

Immunohistochemical demonstration of serotonin neuron system in the central nervous system of the Japanese dogfish, Scyliorhinus torazame (Chondrichthyes).

The distribution of serotonin immunoreactivity in the brain of the Japanese dogfish (Scyliorhinus torazame) was studied with the peroxidase-antiperoxidase immunohistochemical method with serotonin antiserum. The somata of the serotonin neurons were located in the raphe regions of the brain stem and the spinal cord. A small number of serotonergic neurons were also distributed as cerebrospinal-fluid contacting neurons in the organum vasculosum hypothalami (OVH) and the paraventricular organ (PVO). These neurons were classified into nine groups (S1-S9): spinal cord (S1), rhombencephalon (S2-S6), mesencephalon (S7), and prosencephalon (OVH, S8 and PVO, S9). Processes of the serotonin neurons were widely distributed in the central nervous system, forming dense networks in various regions. The highest concentrations of these fibers were in the dorsal area of the vagal lobe, the nucleus isthmi, the tuberculum posterium, the distal part of the PVO, and the dorsal regions of the olfactory tubercle.

Animals↗

[Accessory use of protease-inhibiting agents for disease remission in a patient with autoimmune hemolytic anemia associated with B-CLL].

Protease inhibiting agents, which have inhibitory effects on complement system, were used to treat a patient with autoimmune hemolytic anemia (AIHA) associated with B cell chronic lymphocytic leukemia (B-CLL). Although this patient had failed to respond thoroughly to prednisolone, the additional use of protease inhibitors induced a disease remission of hemolytic anemia. The result suggests that complement components are of importance in the pathogenesis of hemolysis in AIHA, and supports the accessory use of protease inhibiting agents in autoimmune hematologic diseases associated with the complement activation and hypersplenism.

Aged↗

Immunohistochemical study on fetal raphe samples transplanted into the leptomeningeal tissue of 5,6-dihydroxytryptamine-treated adult rats.

Pieces of fetal midbrain raphe containing serotonergic and dopaminergic neurons were transplanted into the leptomeningeal tissue of adult host rats that had previously been denervated by treatment with 5,6-dihydroxytryptamine. One, 2 and 5 months after transplantation, the rate of neuronal survival in the grafted tissue and the extent of axonal outgrowth into the host brain were studied by use of serotonin and tyrosine hydroxylase (TH) immunohistochemistry. The survival rate of the grafts in the 1-month group was approximately 70%. Neurons containing either serotonin or catecholamine were demonstrated by means of immunocytochemical procedures in the grafts. Two and 5 months after transplantation, serotonin-immunoreactive nerve fibers were densely distributed throughout the graft tissue, while TH-immunoreactive fiber elements were restricted to an area near the somata of TH-positive neurons. Numerous serotonin-immunoreactive fibers derived from the transplant were found in the leptomeningeal tissue surrounding the graft, on the wall of neighboring blood vessels, and also in the adjacent parenchyma of the host brain. Outgrowing TH-immunoreactive nerve fibers were not observed in the host brain, although such elements occurred in the leptomeningeal tissue and the wall of the larger blood vessels. These results suggest that the serotonergic and catecholaminergic (dopaminergic) neurons located in transplants of the raphe nuclei show different patterns when reinnervating the host tissue.

5,6-Dihydroxytryptamine↗

Combined method of fluorescence tracer technique and PAP immunohistochemistry for discrimination of the transplanted cells.

The retrograde fluorescence tracer, True Blue (TB), was injected into the forebrain septal area of neonatal rats. After 3 to 6 days the brains of these animals were carefully removed and placed in ice-cold sterilized physiological saline containing 1% glucose. Under the surgical microscope, one or two pairs of mesencephalic tissue samples, each containing a dorsal raphe nucleus, were punched out and transplanted into the third ventricle of a 5,6-DHT-pretreated adult rat. One month after transplantation, all animals were perfused and their brains sectioned using a cryostat. The sections were examined using a fluorescence microscope, and then processed for serotonin immunohistochemistry. The grafts were found to be successfully implanted and connected with the middle portion of the third ventricle. Four types of neurons, i.e., TB-labeled, serotonin-labeled, both TB- and serotonin-labeled, and non-labeled neurons, were detected in the grafts. This double-labeling method is considered to be a useful technique in characterizing the neurons in grafts which consist of a heterogeneous cell population.

Animals↗

Brain natriuretic peptide in the porcine spinal cord: an immunohistochemical investigation of its localization and the comparison with atrial natriuretic peptide, substance P, calcitonin gene-related peptide, and enkephalin.

Immunohistochemistry was used to localize brain natriuretic peptide in the porcine spinal cord and to compare it with that of atrial natriuretic peptide, substance P, calcitonin gene-related peptide and [Met]enkephalin. Brain natriuretic peptide-immunoreactive varicose fibers were observed in lamina I and the inner portion of lamina II of the dorsal horn. Semiquantitative analysis showed that the highest density of brain natriuretic peptide-immunoreactive varicosities was in the lumbosacral and coccygeal segments. The distributional pattern of brain natriuretic peptide-immunoreactive nerve fibers in the spinal cord was unique and quite distinct from that of the other neuropeptides studied. These neuroanatomical findings suggest that brain natriuretic peptide may play a role in the regulation of nociceptive processing in the spinal cord, either alone or with bioactive substances.

Animals↗

Paget's disease of the male breast--report of a case and histopathologic study.

We report a 61-year-old male with mammary Paget's disease. Physical examination revealed a slightly exudative erythema at the areola and a reddish, enlarged left nipple. No tumor or left axillary lymph nodes was palpable. He underwent a left modified radical mastectomy. Histologically, there was an intraductal carcinoma in the upper portion of the mammary ducts. The axillary lymph nodes that were examined were free of metastasis. Paget cells had neither estrogen nor progesterone receptors. We speculated that the histogenesis of Paget cells involved carcinoma cells that invaded the epidermis of the nipple.

Breast Neoplasms↗

Calcitonin gene-related peptide-binding sites of porcine cardiac muscles and coronary arteries: solubilization and characterization.

Calcitonin gene-related peptide (CGRP)-binding sites were solubilized, using digitonin, from the porcine spinal cord, atria, and coronary arteries. The specific binding of 125I-human alpha-CGRP to the solubilized binding sites was inhibited by human alpha- and beta-CGRP and by rat alpha-CGRP, but not by angiotensin II or human calcitonin. Scatchard plot analysis of saturation gave the same KD value for CGRP in the crude membrane fractions of the tissues examined. The affinity of CGRP to the binding sites was decreased by solubilization in the atria and coronary arteries, but not in the spinal cord. Affinity labeling followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed distinct molecular sizes of the specific binding sites among the tissues; 70K for the spinal cord, 70K and 90K for the coronary arteries, and 70K and 120K for the atria. These results indicate that the molecular characteristics of the specific binding sites of CGRP in the cardiovascular system are distinct from those in the central nervous system.

Animals↗