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Biomedical subjects

K Nagata

Publications and source records attributed to K Nagata.

At least 307 records · Page 17Linked to original sources
PubMed1998

Expression and localization of collagen-binding stress protein Hsp47 in mouse embryo development: comparison with types I and II collagen.

Heat shock protein (Hsp)47 is a collagen-binding stress protein localized in the endoplasmic reticulum and is thought to have chaperone-like functions that are specific to procollagen biosynthesis. In previous papers, we reported that the expression of Hsp47 is closely correlated with that of various types of collagen in various cell lines and also in the progression of experimental liver fibrosis. In the present study, the expression of Hsp47 was examined during the development of mouse embryos by immunostaining with an anti-Hsp47 antiserum. The spatio-temporal correlation of the expression of Hsp47 with those of types I and II collagen was also examined using specific antisera. Hsp47 expression during embryogenesis was observed mainly in mesoderm and in tissues that are derived from mesoderm, such as connective tissue, cartilage, bone, notochord and somites. Hsp47 was also detected in tissues derived from the neural crest mesenchyme. In the central nervous system, Hsp47 was detected in some restricted regions where cells proliferate, such as the ventral area of the neural tube and choroid plexus. Immunostaining for types I and II collagen revealed the spatial and temporal correlations of the expression of these proteins with that of Hsp47. These results suggest the biological importance of Hsp47 as a collagen-specific molecular chaperone in the mouse developmental program.

Animals↗
PubMed1998

Induction of abundant osteoclast-like multinucleated giant cells in adjuvant arthritic rats with accompanying disordered high bone turnover.

The development of an in vivo system for investigating osteoclast differentiation is important because molecular events occurring in vivo can be observed during the differentiation of the authentic osteoclasts. In adjuvant arthritic rats, an experimental model of human rheumatoid arthritis, extensive bone resorption is observed in the distal diaphysis of the tibia. In the area of extensive bone resorption, it is always accompanied with clusters of numerous multinucleated giant cells (MGCs) as well as bone-resorbing osteoclasts. Here we characterized the morphological properties of these MGCs with the use of enzymehistochemical and immunohistochemical techniques. Extensive destruction but also a marked formation of the inner and outer bone surfaces were the predominant features in the tibiae of such arthritic rats 4 weeks after the adjuvant injection. Numerous MGCs were frequently clustered in the bone marrow spaces located apart from the bone matrices. Although the MGCs lacked ruffled borders, these cells were rich in mitochondria and vacuoles. These multinucleated cells revealed a positive reaction for tartrate-resistant acid phosphatase but a negative reaction for non-specific esterase staining. Most of these MGCs expressed the Kat 1-antigen, an immunological marker specifically expressed on the cell surface of rat osteoclasts. In a dentin resorption experiment using a cluster of MGCs excised from the bone marrow tissues of the tibial distal diaphyses of rats with adjuvant arthritis, many resorption lacunae were formed on dentin slices after a 3-day culture. These results suggest that the majority of the MGCs are osteoclasts but not macrophage polykaryons.

Animals↗
PubMed1998

Urinary iodine and thyroid antibodies in Okinawa, Yamagata, Hyogo, and Nagano, Japan: the differences in iodine intake do not affect thyroid antibody positivity.

Excess iodine intake may affect the development of Hashimoto's thyroiditis. Kelp consumption is very high in Okinawa. We expected a high prevalence of Hashimoto's thyroiditis in Okinawa. We studied urinary iodine excretion and the positivities of anti-thyroglobulin antibodies (TGAb) and anti-thyroid peroxidase antibodies (TPOAb) in the residents of Nishihara in Okinawa, Yamagata in Yamagata, Kobe in Hyogo, and Hotaka in Nagano, Japan. TGAb and/or TPOAb were positive in 142 (13.7%) of 1039 subjects in Nishihara, in 16 (16.0%) of 100 subjects in Yamagata, in 31 (13.4%) of 232 subjects in Kobe, and in 35 (13.9%) of 252 subjects in Hotaka; TGAb and/or TPOAb positivity was about the same in these 4 areas. One tenth of the subjects with positive TGAb and/or TPOAb had hypothyroidism; the frequencies of hypothyroidism in those with positive TGAb and/or TPOAb were about the same in Nishihara, Yamagata, Kobe, and Hotaka. The iodine concentration in samples of morning urine correlated well with the 24-h urine iodine excretion. The urinary iodine excretion was 1.5 mg/day in Nishihara. There were no differences between Nishihara and Yamagata in the urinary iodine concentration, but the urinary iodine concentrations in Kobe and Hotaka were less than those in Nishihara or Yamagata. The amounts of iodine excretion in Kobe and Hotaka were moderate, and less than those in Nishihara or Yamagata. The amounts of iodine intake in Kobe and Hotaka were less than those in Nishihara or Yamagata, but TGAb and/or TPOAb positivity was about the same in Nishihara, Yamagata, Kobe, and Hotaka. The differences in dietary iodine intake do not affect TGAb and/or TPOAb positivity.

Administration, Oral↗
PubMed1998

Subdural empyema caused by hematogenous dissemination from an abscess in thigh to a preexisting chronic subdural hematoma--case report.

A 63-year-old male with a preexisting chronic subdural hematoma presented with progressive confusion and left hemiparesis as well as high fever. Subdural empyema was strongly suspected. At surgery, the empyema was encapsulated by definite inner and outer membranes. Cultures isolated from the subdural fluid and from an abscess of his left thigh yielded methicillin-resistant Staphylococcus aureus. A pulsed-field gel electrophoresis showed these two strains were genetically identical. Hematogenous infection of a preexisting subdural hematoma is an extremely rare cause of subdural empyema.

Abscess↗
PubMed1998

MRI monitoring of tarsal navicular stress fracture healing--a case report.

Stress fractures of the tarsal navicular bone are rare injury and assessing its healing is difficult. Tenderness over the tarsal navicular on physical examination is the most reliable sign for assessing fracture healing. However, it is desirable to assess fracture healing with some imaging method. We used serial magnetic resonance imaging (MRI) to assess healing in a patient with a tarsal navicular stress fracture. MRI was useful for the assessment of fracture healing of tarsal navicular stress fracture in our case.

Adolescent↗
PubMed1998

A new reduction technique for a patellar fracture.

We report 4 cases of patellar fracture with skin injury over the patella which were treated operatively immediately after onset with a new reduction technique using Ilizarov pins. This technique made it possible to perform early operative treatment even in the cases with skin injury over the patella which prevents conventional surgical approach.

Adult↗
PubMed1998

Multiple regression analysis of airway responsiveness in adult asthmatic patients.

The aim of this study was to determine which background variables exert the most influence on airway responsiveness in adult asthmatic patients. The relationships between airway response and background variables were investigated by multiple linear and logistic regression analysis in 97 asthmatic patients. Airway responsiveness was measured by the oscillation technique during methacholine inhalation challenge. The regression analyses revealed that modified Aas score "one of asthma severity score", was the major factor contributing to airway hyperreactivity. We conclude that the number of attacks during a previous year is the most important background factor related to airway hyperresponsiveness on a clinical basis.

Asthma↗
PubMed1998

Germinoma causing wallerian degeneration. Case report and review of the literature.

Germinomas occurring in the thalamus and basal ganglia sometimes cause atrophy of the cerebral hemisphere on the affected side. The authors present the case of a 12-year-old girl with a germinoma that developed in the basal frontal lobe and cerebral basal ganglia. Magnetic resonance imaging showed atrophy not only of the cerebrum but also of the brainstem. A T2-weighted image revealed an area of high intensity that proved to be wallerian degeneration extending from the corona radiata and internal capsule to the brainstem. The authors suggest that this pathological change may be involved in the development of the symptoms and hemiatrophy associated with germinomas in this region of the brain.

Brain Neoplasms↗
PubMed1998

Local cerebral blood flow autoregulation following "asymptomatic" cerebral venous occlusion in the rat.

OBJECT: Maintenance of cerebral blood flow (CBF) autoregulation in the brain is of major importance for patient outcome in various clinical conditions. The authors assessed local autoregulation after "asymptomatic" cortical vein occlusion. METHODS: In Wistar rats, a single cortical vein was occluded photochemically by using rose bengal and fiberoptic illumination. In rats with bilateral carotid artery occlusion, mean arterial blood pressure (MABP) was lowered in 5-mm Hg increments down to 40 mm Hg by using hypobaric hypotension. Local CBF at each pressure level was assessed by performing laser Doppler (LD) scanning at 25 (5 x 5) locations within bilateral cranial windows. In this manner, the lower limit of autoregulation (LLA) was detected. The LLA was 60 mm Hg in both right and left hemispheres in Group A (five rats), in which the animals received illumination without rose bengal and had no venous occlusion. Of the 11 rats that underwent vein occlusion, three developed severe reductions in local CBF and/or a growing venous thrombus and were distinguished as Group C (symptomatic; three rats); from previous work we know that those animals are bound to experience venous infarction. The remaining rats formed Group B (asymptomatic; eight rats). In this group the LLA remained at 60 mm Hg in the left hemisphere without occlusion, whereas, in the right cortex with the occluded vein, the LLA was found to be 65 mm Hg. Below a carotid stump pressure of 25 mm Hg regional CBF in the affected hemisphere dropped more abruptly to a possibly ischemic range than that in the opposite normal hemisphere. CONCLUSIONS: The results of the present study suggest that cerebral venous circulation disorders are manifested via additional pathways, that is, from a partially impaired local autoregulation in the vicinity of the occluded vein, even under conditions in which the vein occlusion itself does not cause brain damage. Care should be taken in the control of blood pressure in patients with this pathological condition.

Analysis of Variance↗
PubMed1998

[Efficacy of granisetron, a 5-HT3 antagonist, in the prevention of nausea and vomiting induced by conditioning for hematopoietic stem cell transplantation].

One hundred and eleven patients receiving conditioning regimens for hematopoietic stem cell transplantation (HSCT) were administered a single intravenous dose (40 micrograms/kg) of granisetron before chemo-radio therapy. The efficacy of the drug was assessed every 24 hours, rating the control of nausea and vomiting as complete, major, minor or failure. On day 1, 23 of 48 patients (47.9%) who received cyclophosphamide (60 mg/kg/day), achieved control of emesis with complete or major response. On day 2, 17 of 47 patients (36.2%) achieved control emesis. During total body irradiation (TBI) (10 approximately 12 Gy/2 approximately 3 days), 21 of 33 patients (63.6%) achieved control of emesis on day 1 and 22 of 32 patients (68.6%) achieved control of emesis on day 2. During melphalan administration (60 approximately 100 mg/m2/day), 20 of 28 patients (71.4%) achieved control of emesis on day 1. Adverse effects were observed in seven patients but were not serious. We concluded that granisetron has a major role in preparation for HSCT.

Adolescent↗
PubMed1998

[Analysis of tumor vascular density using the window chamber technique].

Vascular structure is indispensable for a tumor to maintain its growth. The structure also affects drug delivery over chemotherapy, and oxygen tension in the tissue during irradiation. Therefore, measuring the vascular density in the tumor will help to reach an expected level or to evaluate the effect of those therapies. Through previous observation, changes in vascular structure, like the vascular density, have been reported. However, the tissue was usually removed from the deceased animal and examined in the microscope. Not many studies have shown changes in one and the same animal's tissue. In this study, we used the dorsal flap window chamber technique, and observed changes in the development of vascular structure and vascular density in a tumor. Window chambers were attached to the backs of 3 rats, and they anesthetized every 24 hours for microscopic observation. Vascular growth in the tumor started 8 to 9 days after implantation. Their average vascular density was about 25%, and this ratio continued till necrosis started in the tumor. "Necrosis occurs in a tumor because its growth is so rapid that the vascular development can not maintain the same speed." This has been a kind of established theory. During observation, we recognized blood stagnation in vessels as the tumor grew, and the relationship between tumor size and its vascular density was significant (r = 0.926). Our data lead us to another conclusion that "Vascular growth is as fast as tumor growth, keeping a ratio of about 25%, but necrosis is caused by deficiency of blood flow circulation."

Animals↗
PubMed1998

Modulation of the neuronal nicotinic acetylcholine receptor-channel by the nitromethylene heterocycle imidacloprid.

Nitromethylene heterocycle insecticides are known to act on the nicotinic acetylcholine receptor-channel. The effects of the nitromethylene heterocycle, imidacloprid, on the nicotinic acetylcholine receptor-channel of clonal rat phaeochromocytoma (PC12) cells were studied using whole-cell and single-channel patch clamp methods. Imidacloprid suppressed carbachol-induced whole-cell currents in a dose-dependent manner, and this compound itself generated small currents. Multiple conductance states of single-channel currents were also evoked by imidacloprid at the nicotinic acetylcholine receptor-channels. The most frequently generated single-channel currents showed two conductance states, 25.4 and 9.8 pS, which were identical to the conductance states of acetylcholine-generated currents. The mean open time and burst duration of the main conductance currents induced by imidacloprid were shorter than those induced by acetylcholine. Co-application of imidacloprid and acetylcholine caused some interactions at the two conductance states. Mean open time and mean burst duration of the main conductance state currents evoked by acetylcholine were decreased by the co-application of imidacloprid as compared with those induced by acetylcholine alone. In conclusion, imidacloprid has both multiple agonist and antagonist effects on the neuronal nicotinic acetylcholine receptor-channels.

Acetylcholine↗
PubMed1998

Calcified pseudoaneurysm of the left ventricle.

Left ventricular pseudoaneurysm following acute myocardial infarction generally has an extremely poor prognosis without surgical repair. A rare case of long term survival for 23 years following cardiac rupture with subsequent development of a left ventricular pseudoaneurysm after acute myocardial infarction is reported. The patient suffered acute inferoposterior myocardial infarction in July 1974 at the age of 58 years. Clinical course and findings obtained on reassessment in 1992 (transesophageal echocardiography, chest computed tomography and left ventriculography) confirmed a left ventricular pseudoaneurysm. The patient refused surgical resection of the lesion, but remained alive and well in 1997 (81 years old). In this case, it is considered that containment of hemorrhage by pericardial adhesion prevented immediate tamponade and sudden death.

Aged↗
PubMed1998

[Swyer-James syndrome with pneumothorax].

We report a case of Swyer-James syndrome with pneumothorax. A 20 year-old man was admitted to our hospital with dyspnea. Right pneumothorax was diagnosed by chest X-ray. He had a history of current pneumonia in childhood. After improvement of the pneumothorax, chest X-ray revealed hyperlucency of the right upper lung. Chest-CT revealed a low attenuation area and a cystic space in the right upper lobe. Xenon-133 clearance was delayed in ventilation scintigraphy. Bronchography showed cylindrical bronchiectasis in the proximal bronchi and poor filling of the peripheral bronchi in the right upper lobe. Pulmonary angiography showed a small right upper pulmonary artery. Swyer-James syndrome was diagnosed. The pneumothorax was probably caused by weakness of the cystic spaces.

Adult↗
PubMed1998

[Clear cell ependymoma--a case report].

A case of intraaxial clear cell ependymoma is reported. A 46-year-old man complained of right hemiparesis. CT scan showed a mass lesion on the median plane with a huge cyst in the left frontal lobe. MRI showed an iso-low intensity mass by T1-weighted image. The tumor was heterogeneously enhanced by Gd-DTPA and the wall was enhanced as well. Angiogram revealed a tumor stain from the right internal carotid artery. The main mass of the tumor was totally removed but the cystic wall was left removed. Histopathological examination revealed clear cell ependymoma. Immunohistochemical examination revealed that, although vimentin and NSE were positive, GFAP, synaptophysin and S-100 were negative. Ultrastructual examination revealed cilia, microvilli and desmosomal junctions. The patient fully recovered after operation and showed no sign of recurrence after an year of follow-up. Clear cell ependymoma is a rare variant of ependymoma. Ultrastructual examination was more useful than immunohistochemical examination for diagnosis.

Brain Neoplasms↗
PubMed1998

[Comprehensive medicine and 17-KS-S].

In order to evaluate QOL from the perspective of comprehensive medicine, a self-rated QOL Questionnaire and urine 17-KS-S (abbreviated S), 17-OHCS (OH), S/OH were examined in 268 patients (including 11 terminally ill cancer patients) and 31 nurses. Lower S and S/OH were observed in both groups, but OH was higher in patients' group and lower in the nurses' group. Total QOL score was lower in patients' group, but higher in nurses' group. The correlation of each parameter, S, OH and S/OH was related to QOL items. Among terminally ill cancer patients, supplementary treatments were performed. During the course, the elevation of S were observed. In conclusion, S, OH and S/OH were related to QOL and they were considered an objective method of evaluating QOL.

17-Hydroxycorticosteroids↗