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Biomedical subjects

Y Kato

Publications and source records attributed to Y Kato.

At least 73 records · Page 4Linked to original sources
PubMed2003

Varicella exposure in a neonatal medical centre: successful prophylaxis with oral acyclovir.

In December 2000, a female infant hospitalized in our Neonatal Care Centre was infected with varicella by her mother. Although prophylactic intravenous acyclovir was administered at a dose of 15 mg/kg daily, she later developed varicella during her hospital stay. We therefore initiated control procedures to prevent further hospital-acquired infections. Oral acyclovir (40 mg/kg daily divided into four doses) was administered prophylactically to six preterm infants in contact with the varicella patient. None of six preterm infants subsequently developed clinical varicella or had any adverse effects associated with acyclovir administration. It is suggested that prophylactic administration of oral acyclovir (40 mg/kg daily) might prevent hospital-acquired varicella-zoster virus (VZV) infections, and that oral acyclovir may be an option for VZV prophylaxis in situations where VZV immunoglobulin is not available.

Acyclovir↗
PubMed2003

Receptor signaling mechanisms underlying muscarinic agonist-evoked contraction in guinea-pig ileal longitudinal smooth muscle.

1 In guinea-pig ileal longitudinal muscle, muscarinic partial agonists, 4-(N-[3-chlorophenyl]-carbomoyloxy)-2-butynyl-trimethylammonium (McN-A343) and pilocarpine, each produced parallel increases in tension and cytosolic Ca(2+) concentration ([Ca(2+)]c) with a higher EC(50) than that of the full agonist carbachol. The maximum response of [Ca(2+)]c or tension was not much different among the three agonists. The Ca(2+) channel blocker nicardipine markedly inhibited the effects of all three agonists 2 The contractile response to any agonist was antagonized in a competitive manner by M(2) receptor selective antagonists (N,N'-bis[6-[[(2-methoyphenyl)methyl]amino]hexyl]-1,8-octanediamine tetrahydrochloride and 11-[[2-[(diethlamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4] benzodiazepine-6-one), and the apparent order of M(2) antagonist sensitivity was McN-A343>pilocarpine>carbachol. M(3) receptor selective antagonists, 1,1-dimethyl-4-diphenylacetoxypiperidinium iodide and darifenacin, both severely depressed the maximum response for McN-A343, while darifenacin had a similar action in the case of pilocarpine. Both M(3) antagonists behaved in a competitive manner in the case of the carbachol response. 3 McN-A343 failed to release Ca(2+) from the intracellular stores, and the Ca(2+)-releasing action of pilocarpine was very weak compared with that of carbachol. All three agonists were capable of increasing Ca(2+) sensitivity of the contractile proteins. 4 McN-A343 rarely produced membrane depolarization, but always accelerated electrical spike discharge. Pilocarpine effect was more often accompanied by membrane depolarization, as was usually seen using carbachol. 5 The results suggest that muscarinic agonist-evoked contractions result primarily from the integration of Ca(2+) entry associated with the increased spike discharge and myofilaments Ca(2+) sensitization, and that Ca(2+) store release may contribute to the contraction indirectly via potentiation of the electrical membrane responses. They may also support the idea that an interaction of M(2) and M(3) receptors plays a crucial role in mediating the contraction response.

(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethy↗
PubMed2003

Induction of cutaneous delayed hypersensitivity reactions in mice sensitized with intragastrically administered hapten: activation of Langerhans cells in the sensitization and elicitation phases.

BACKGROUND: As seen in atopic dermatitis, allergic diseases often produce lesions both in the gastrointestinal tract and the skin, suggesting the involvement of an immunological relationship between the two organs in the pathogenesis. OBJECTIVES: To study the role of gastric and epidermal Langerhans cells (LCs) in the sensitization and elicitation phases, respectively, of cutaneous delayed-type hypersensitivity (DTH) reactions to intragastrically administered hapten. METHODS: BALB/c mice, which were subjected to intragastric administration of trinitrochlorobenzene 5 days previously, received an elicitative challenge of the same hapten to the ear skin. Sections of the ear were immunostained for CD4 and CD8. Epidermal sheets of the ear and epithelial sheets of the forestomach were immunostained for I-A and observed under a confocal laser scanning microscope. RESULTS: Cutaneous DTH reactions were induced in mice, as demonstrated by an increase in ear thickness and a prominent infiltration of CD4+ and CD8+ lymphocytes at 24-36 h after the elicitative challenge. In the elicitation phase, epidermal LCs showed a significant increase in size, indicating in vivo activation, at 24 h. In the sensitization phase, gastric LCs increased in size at 2 h, became round at 6 h, and decreased in number at 24 h, possibly representing the sequential events of LC activation and migration from the epithelium. CONCLUSIONS: The present study demonstrated that gastric LCs and epidermal LCs were activated in vivo in the sensitization and elicitation phases, respectively, of cutaneous DTH reactions in orally sensitized mice.

Animals↗
PubMed2003

First night effect of an interocclusal appliance on nocturnal masticatory muscle activity.

The purpose of this study was to examine the effect of an interocclusal appliance on nocturnal masticatory muscle activities. Six healthy Japanese males (mean age: 26.8 years) participated in this study. Electromyographic (EMG) activities of the right anterior temporalis and masseter muscles were recorded using a portable EMG recording unit at night both with and without an interocclusal appliance. In both muscles, the maximal EMG activity and the number of bruxing events decreased significantly by wearing the appliance. Moreover, the duration of a higher level of muscle activity was decreased while that of a lower level of muscle activity increased by wearing the appliance in both muscles. These findings suggest that nocturnal masticatory muscle activity is significantly reduced by wearing an interocclusal appliance, and that the use of such an appliance at night could help to relax masticatory muscles.

Adult↗
PubMed2003

Micromanipulator: effectiveness in minimally invasive neurosurgery.

Minimally invasive surgeries by innovative approaches are practiced in all fields. The evolution of microneurosurgery has revolutionized the results in neurosurgery. Use of endoscopes and navigation has made microsurgery less invasive. Another development to make minimally invasive microneurosurgery further lesser invasive is the use of micromanipulator. The use and effectiveness of manually controlled micromanipulator system is presented. The manually controlled micromanipulator system consists of three parts, i.e., a basic micromanipulator, manipulator supporting device and the manual control. The micromanipulator fitted in supporting device is arranged before the start of surgery. The supporting device used is pneumatically driven powered endoscopic holding device (Mitaka Kohki Co., Tokyo) In maximum number of times we used the system for endoscopic assisted cerebrovascular microneurosurgery. In a span of two months we used it in thirty aneurysm clipping surgeries. The endoscope fitted in system has three ranges of motions (forward/backward, upside/down and sideways). We use MACHIDA rigid endoscope with internal diameter of 2.7 mm (smallest diameter endoscope available). Special features of this endoscope are accurate visualization at a deeper plane, stable movements and availability of single focus point for long time. All these features are valuable during pre- and postoperative clipping observation. The aim of development of micromanipulator system was to further reduce invasiveness. A significant improvement in manual dexterity is possible when working through the micromanipulator interface, which dampens human physiological tremor. The physiological tremor would render the manual dexterity unsafe at the end of lever arm of long instruments. Thus, the use endoscope becomes practical. The minimally invasive microneurosurgery can be further made lesser invasive by use of micromanipulator and we are convinced that this will facilitate more accurate and promising results in microneurosurgery.

Cerebral Revascularization↗
PubMed2003

Molecular cloning of porcine neuronatin and analysis of its expression during pituitary ontogeny.

We cloned and sequenced two types (alpha and beta type) of cDNA from the porcine anterior pituitary cDNA library, encoding neuronatin that has been cloned as a gene expressed by the fetal developing brain. Nucleotide sequences of alpha and beta type were identical except for two gaps, suggesting that they were produced by an alternative splicing. The amino acid sequences showed a high homology (more than 94 %) compared to those of other mammals, including human, rat, and mouse. In this study, RT-PCR was performed for the RNA samples prepared from the porcine fetal and postnatal pituitaries. The results showed that two types of neuronatin are expressed through the fetal stages, from day 40 to day 110 in both sexes. The relative amounts of alpha to beta type reversed just after birth in both sexes, and both amounts increased further in the postnatal anterior pituitary. This increased expression after birth is quite different from the brain in which the expression of neuronatins decreased, indicating the distinct role of the neuronatin in pituitary and brain. Finally, we found a pituitary cell type specific localization, especially in gonadotroph cell lines LbetaT2, of beta-neuronatins.

Amino Acid Sequence↗
PubMed2003

Surgical strategies for treatment of giant or large intracranial aneurysms: our experience with 139 cases.

Giant or large intracranial aneurysms are the vascular neurosurgeon's greatest challenge. At our department, we have treated one hundred and thirty nine patients with giant or large intracranial aneurysms between 1975 and 2001. These included 37 partially thrombosed giant aneurysms. 75 aneurysms were giant (> 2.5 cm) and 64 were large aneurysms (2-2.5 cm). Three-dimensional computed tomography angiograms were performed in patients besides MRI angiography and digital subtraction angiography. These were found to be very valuable in the preoperative assessment of surgical anatomy of the aneurysm with respect to the branch arteries and perforators origin besides knowing the relations to the skull base. With our experience in surgical treatment of these 139 cases, we find that the basic technique is trapping and evacuation and not just clipping of the aneurysm neck but also reconstruction of the artery bearing the aneurysm, especially with wide-necked aneurysms. Use of multiple clipping, tandem clipping or dome clipping as per the intraoperative situation, is very helpful in dealing with giant aneurysms as also is the use of different types of clips like fenestrated clip with straight clip (combination clipping), booster clip, dome clips etc. While selecting surgical strategy for partially thrombosed giant aneurysm, securing the neck is most important. If the neck is too narrow to reconstruct, aneurysmectomy with anastomosis is one of the surgical strategies. An extracranial intracranial bypass should be considered in cases where clipping or parent artery ligation is expected to be associated with compromise of cerebral circulation.

Aged↗
PubMed2003

Spontaneous dissecting aneurysm of middle cerebral artery: a case report with review of the literature.

We report a case of a dissecting aneurysm of the middle cerebral artery (MCA) and its treatment strategies. A 50-year-old male patient presented with occipital and neck pain for 2 days. CT scan revealed subarachnoid hemorrhage (SAH) in the region of the right sylvian fissure. A left carotid angiogram showed a dissecting aneurysm of the left MCA (M1). He was treated surgically by a pterional trans-sylvian approach. Clipping was done along with additional reinforcement by wrapping to completely obliterate the neck of the aneurysm. On reviewing the literature, we think that dissecting aneurysms seem to be one of the important causes of SAH and cerebral infarction of unverified origin. If an MCA dissecting aneurysm is identified, especially located in the proximal portion, surgical treatment must be considered. These patients merit a close follow-up.

Adult↗
PubMed2003

Cadherin-related neuronal receptors in incisor development.

Cadherins are cell adhesion molecules that are critical for tissue development. In this report, we identified members of the cadherin family cadherin-related neuronal receptors (CNRs) 1 and 5 expressed in rat incisors by the differential display method. Quantitative RT-PCR revealed that CNR1 mRNA is expressed in the secretory stage but reduced in the early-maturation stage, while CNR5 mRNA is expressed in both these stages. In situ hybridization showed that strong expression of CNR1 is strong in the secretory stage, but reduced in the early phase and diminished in the late phase of the early-maturation stage. CNR5 mRNA is expressed almost at the same levels in the secretory and in the early phase of the early-maturation stages but is absent in the late phase of the early-maturation stage. Both CNR1 and 5 mRNA are continuously expressed in odontoblasts. Immunohistology showed that CNR proteins are expressed in the secretory and early-maturation stages of ameloblasts, but no protein expression at the late-maturation stage was observed. CNR proteins were continuously expressed in odontoblasts. We found that recombinant CNR1 binds dental epithelial and mesenchymal cells through N-terminal domain EC1 in vitro. These results suggest that CNR1 and CNR5 may play an important role in enamel and dentin formation, probably through cell-cell and/or cell-matrix interactions.

Ameloblasts↗
PubMed2003

[Coronary endarterectomy and on-lay patch anastomosis in a case with unstable angina due to diffusely diseased coronary artery].

A 76-year-old woman with unstable angina due to diffusely diseased coronary artery successfully underwent coronary artery bypass grafting (CABG) using endarterectomy and on-lay patch anastomosis. She had triple vessel disease in the coronary artery and all of them were diffusely stenotic. It was impossible to undertake simple CABG. We were able to perform 3 coronary artery bypass grafting using endarterectomy and on-lay patch anastomosis. The postoperative course was uneventful and postoperative angiogram revealed well patent 3 grafts. Coronary endarterectomy and on-lay patch anastomosis were effective procedure in a patient with diffusely diseased coronary artery.

Aged↗
PubMed2002

Picosecond snapshot of the speckles from ferroelectric BaTiO3 by means of x-ray lasers.

A picosecond x-ray laser speckle has been conducted to study the dynamics of a disordered surface domain structure (BaTiO3 with 90 degrees c/a domains) as a function of temperature for the first time. The transient surface structures induced by ferroelectric domains decrease as temperature increases towards the Curie temperature T(c) and completely disappear above T(c). The dramatic change of the spatial configuration of the c/a domains was observed to occur from a temperature 2 degrees C below T(c), near which the average correlated domain size at equilibrium decreases as (T(c)-T)(0.37+/-0.02).

Journal Article↗
PubMed2002

Thoracoscopic internal mammary sentinel node biopsy for breast cancer.

Sentinel node (SN) biopsy has changed the management of breast cancer. This pilot study assessed the utility of lymphatic mapping and thoracoscopic SN biopsy for internal mammary node (IMN) staging. Forty-nine breast cancer patients underwent lymphatic mapping using 99mTc-tin colloid. Patients with IMSNs underwent thoracoscopic biopsy. Lymphoscintigraphy showed IMSNs in 15 of 49 cases (31%). The incidence of IMN drainage was relationed to age and tumor location; 50% of patients younger than age 40 and 43% with tumors located in inner quadrants had IMN drainage. The thoracoscopic procedure was performed in 11 of 15 patients, and 18 IMSNs were removed; the time of the procedure ranged from 20 to 60 min. No patients had complications from the procedure. Two of 11 patients (18%) had IMSN metastasis, and one of them had only IMN metastasis. Lymphatic mapping and the thoracoscopic approach were useful for IMSN biopsy. They may enable the physician to make an appropriate treatment decision for breast cancer.

Adult↗
PubMed2002

Proposed double-layer target for the generation of high-quality laser-accelerated ion beams.

In order to achieve a high-quality, i.e., monoenergetic, intense ion beam, we propose the use of a double-layer target. The first layer, at the target front, consists of high-Z atoms, while the second (rear) layer is a thin coating of low-Z atoms. The generation of high-quality proton beams from the double-layer target, irradiated by an ultraintense laser pulse, is demonstrated with three-dimensional particle-in-cell simulations.

Ions↗
PubMed2002

RGD-CAP ((beta)ig-h3) is expressed in precartilage condensation and in prehypertrophic chondrocytes during cartilage development.

RGD-CAP ((beta)ig-h3), isolated from cartilage as a collagen-associated protein, was demonstrated to have a binding ability to collagen and to enhance the adhesion of chondrocytes via integrin alpha(1)beta(1). However, the role of this protein in cartilage development remains unclear. In this study, we investigated the expression of RGD-CAP ((beta)ig-h3) in chick embryos and cultured mesenchymal stem cells (MSCs) during the differentiation to chondrocytes. The effects of recombinant RGD-CAP on adhesion and DNA synthesis of MSCs and mineralization were also examined. Tissue sections from chick embryos at Hamburger-Hamilton (HH) stages 19-37 were immunostained with anti-chick RGD-CAP antibodies. The expression of RGD-CAP was slightest in chick embryos at HH stage 19, whereas a considerable expression of RGD-CAP was observed in the developing vertebrae and precartilage aggregate in the limb bud of chick embryos at HH stage 26. The expression of RGD-CAP was significantly reduced in vertebrae of chick embryo at HH stage 32. Reverse transcriptional polymerase chain reaction (RT-PCR) analysis showed that RGD-CAP was highly expressed in cultured MSCs and decreased by 4-day treatment with 10(-8) M dexamethasone when MSCs proliferated to adipocyte-like cells, whereas it was recovered by co-treatment with 3 ng/ml TGF-beta for 8-12 days when MSCs proliferated to hypertrophic chondrocyte-like cells. The adhesion and DNA synthesis of MSCs cultured on RGD-CAP-coated dishes increased significantly compared with the controls. RGD-CAP was distributed in the prehypertrophic zone in matured cartilage of the vertebrae of chick embryos at HH stage 37. Recombinant RGD-CAP inhibited the mineralization of hypertrophic chondrocytes. These results suggest that RGD-CAP ((beta)ig-h3) exerts an essential role in the early cartilage development by enhancing the adhesion and growth of the pre-chondrogenic cells, and functions as a negative regulator for mineralization at the terminal stage of the chondrogenic differentiation.

Animals↗
PubMed2002

Phosphorylated tyrosine-containing proteins in primary lung cancer correlates with proliferation and prognosis.

To determine the usefulness of tyrosine phosphorylation in evaluating biological characteristics, we attempted to evaluate the relationship between the amount of phosphorylated tyrosine-containing proteins and clinicopathological factors, cell proliferation and outcome in non-small cell lung cancer. To evaluate phosphorylated tyrosine-containing proteins we used 96 surgically resected materials of non-small cell lung cancer and normal peripheral lung, while immunohistochemical evaluation was performed. Cell proliferating ability was evaluated using the labelling index of proliferating cell nuclear antigen-positive nuclear staining cells. There were statistically significant differences between the expression levels of phosphorylated tyrosine-containing proteins of normal and cancerous tissues (P<0.0001). Evaluations based on clinicopathological factors apart from histopathological differentiation, showed no statistically significant differences of phosphorylated tyrosine-containing proteins expression. However, phosphorylated tyrosine-containing proteins correlated with cell proliferation activity evaluated (P((Low, High))<0.0001; P((Low, Int)) <0.0001; P((Int, High))<0.0001). Furthermore, non-small cell lung cancer cases with high expression and intermediate expression of phosphorylated tyrosine-containing proteins had a significantly shorter disease-free postoperative survival than those with low expression of phosphorylated tyrosine-containing proteins using log-rank analysis (P((Low, Int)) <0.0028; P((Low, High))=0.0002). Furthermore, phosphorylated tyrosine-containing proteins expression level statistically contributed to disease-free survival in Cox's proportional hazard model. Therefore, phosphorylated tyrosine-containing proteins in non-small cell lung cancer tissues seem to reflect its biological malignancy, and this evaluation may be valuable for constructing the most appropriate therapeutic strategy.

Aged↗
PubMed2002

The developmental potential of the inner cell mass of blastocysts that were derived from mouse ES cells using nuclear transfer technology.

The present study examined the causes of the low developmental potential of enucleated oocytes that have received ES cells and consequent postnatal death of the young. The inner cell masses (ICM) of nuclear-transferred blastocysts or diploid blastocysts were injected into tetraploid blastocysts (group B) or nuclear-transferred tetraploid blastocysts (group C), respectively. The developmental potential of these groups was compared with tetraploid blastocysts injected with ICM of diploid blastocysts (group A). The potential of reconstituted blastocysts to develop into live young in group B increased slightly (5%) but was significantly lower than that in group A (45%). The rate of postnatal death of young in group B did not decrease. The implantation rate of reconstituted blastocysts in group C was very low and no live fetuses were obtained. The results of the present study indicate that the inferior potential of both ICM and trophectoderm cells of nuclear-transferred blastocysts underlies the low developmental rate of nuclear-transferred oocytes receiving ES cells and the higher rate of postnatal death of ES cell-derived young.

Animals↗
PubMed2002

Longitudinal study of functional spinal alpha motor neuron loss in amyotrophic lateral sclerosis.

Using a microstimulation technique for obtaining motor unit number estimates (MUNEs) of the hypothenar and extensor digitorum brevis (EDB) muscles, we performed a longitudinal study on the natural course of change in the clinical rating scale (Appel score) and of loss of functional spinal alpha motor neurons in amyotrophic lateral sclerosis. The Appel score increased to about 150% of normal at 12 months after onset, about 225% at 18 months after onset, and about 370% at 24 months after onset. By contrast, MUNEs decreased to about 27% of normal at 12 months after onset, about 12% at 18 months after onset, and about 5% at 24 months after onset. The relative merits of these different approaches in detecting changes in the disease process in its early phase are discussed.

Action Potentials↗