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Biomedical subjects

S Kawamura

Publications and source records attributed to S Kawamura.

At least 127 records · Page 7Linked to original sources
PubMed1998

Effects of treatment with nilvadipine on cerebral ischemia in rats.

The protective effects of a Ca2+ antagonist, nilvadipine, on focal cerebral ischemia were studied in male spontaneously hypertensive rats. The animals received either nilvadipine (3mg x kg(-1) x day(-1)) or a vehicle subcutaneously. Group 1 (n=11) was treated for 7 days, and Group 2 (n=11) for 14 days. The middle cerebral artery was occluded on the 6th (Group 1) or 13th (Group 2) day of the treatment, and neuropathological outcomes were quantified 24 hours later. The mean arterial blood pressure was significantly reduced with nilvadipine to normal levels. The % infarct volumes of Groups 1 (37+/-2) and 2 (34+/-3) were significantly less than those of their controls (39+/-3 [n=11] and 40+/-4 [n=12], respectively), although the difference between Groups 1 and 2 was not significant. When infarct areas were compared in each of 8 coronal sections, the infarct size had decreased in the 5 posterior sections in Group 2, but only in 2 sections of Group 1. A significant decrease in the edema volumes was observed in Group 2, but not in Group 1. Thus, nilvadipine provided protective effects against cerebral ischemia in rats having chronic hypertension, and the effects were dependent on the duration of treatment.

Animals↗
PubMed1998

Arterial occlusive lesions following wrapping and coating of unruptured aneurysms.

Seven patients (mean age 57 years) developed arterial occlusive lesions following both wrapping and coating during surgery for unruptured aneurysms. Five patients had no risk factors for arteriosclerosis, and two had hypertension or diabetes mellitus. The aneurysms were located in the middle cerebral artery in four cases, and the internal carotid artery in three. Both 100%-cellulose cotton (Bemsheet) and cyanoacrylate glue (Biobond) were used as reinforcement materials. Postoperative angiography revealed complete clipping, and no parent artery stenoses, although one patient had a non-symptomatic diffuse narrowing in the entire carotid fork 7 days following surgery. Three patients had progressive stroke 4-5 weeks following surgery, and two had no symptoms. Both reinforcement materials were used as little as necessary in the last two patients, but they had either transient ischemic attacks or progressive stroke 2 months following surgery. Arterial steno-occlusion was confirmed angiographically in all patients. These vascular lesions were probably induced by both direct toxicity of the cyanoacrylate glue and fibrosis or granuloma formation caused by the cotton fibers. The observed angiographical reversibility suggests that the cyanoacrylate glue is more likely to be the cause of the lesions than the cotton fibers.

Aged↗
PubMed1998

Effects of dobutamine on brain surface microvessels in rats.

The effects of dobutamine on the diameters of rat pial vessels were investigated in vivo using a closed cranial window technique. Dobutamine (10(-7)-10(-3) M) was dissolved in artificial cerebrospinal fluid (CSF). Arterioles (17-78 microns in diameter) and venules (20-97 microns in diameter) were observed through the cranial window over the left parietal cortex. Superfusion of the brain surface with only artificial CSF had no effect on vessel diameter. Dobutamine, even at a high concentration of 10(-4) M, did not induce significant diameter changes in the pial vessels, compared with control animals. The arterioles showed marked dilatation (+73%) during superfusion with 10(-3) M dobutamine (p < 0.01 vs. control). The venules were also dilated (+12%), although the increased diameter was not statistically different from controls. Therefore, dobutamine did not induce a dose-dependent dilation. The results strongly suggest that dobutamine at clinical dosages does not have a direct vasomotor effect on brain microvessels.

Animals↗
PubMed1998

Redundancy gain in discrimination of colored lights: effects of complexity and eccentricity.

The present study investigated the redundancy gain in discrimination of colored lights. Subjects were requested to discriminate a target from 34 nontarget lights differing from the target in luminance, hue, or both, and RTs were recorded. Experimental variables were the complexity of stimulus pattern and the eccentricity of the target in visual angle. The 35 lights were arranged regularly on an imaginary grid in the low-complexity condition and were arranged randomly in the high-complexity condition. The eccentricity of target was varied from 0 degree to 16 degrees. Only when the stimulus pattern was highly complex and eccentricity was large, the combination of luminance and hue made the subject's discrimination faster than when luminance or hue individually operated as a cue for discrimination. That is, a redundant target effect was found only for a highly complex stimulus pattern and in peripheral vision.

Adult↗
PubMed1998

Multiple streams of time consciousness: a new model of retrospective timing.

This note suggests a new hypothesis for retrospective timing, that, when one experiences a period of time in which plural contexts progress simultaneously, a stream of time consciousness is formed for each context and a temporal judgment to the period is made for each of the streams. In the experiment, 17 subjects observed an event in which plural contexts progressed simultaneously and estimated the time a certain thing occurred during the event. Subjects' estimated times varied with the number of changes in the context which the subjects were required to judge. The hypothesis was supported.

Adult↗
PubMed1998

Articular cartilage repair. Rabbit experiments with a collagen gel-biomatrix and chondrocytes cultured in it.

To repair a full-thickness articular cartilage defect in rabbit knees, we developed a technique of using a collagen gel hardened by cultured allogeneic chondrocytes in it. The gel-chondrocyte composite accumulated an intense metachromatic matrix, and had elasticity and stiffness enough to be shaped easily after 2 weeks' culture in vitro. It was implanted into full-thickness articular cartilage defects. Histologic evaluation was performed up to 6 months after surgery, using a histologic grading scale composed of 5 categories. In the gel-chondrocyte composite implanted group, good repair was observed from as early as 1 day up to 6 months. On the other hand, in the empty control group, no repair was observed 1 day to 2 weeks after the defects were made. At 4 weeks, some repair occurred, but even at 6 months the repair was not good.

Animals↗
PubMed1998

[Severe mycosis-factors with fungus and host].

The deep-seated mycosis occurred in immunocompromized patients. Normally, the deep-seated mycosis became sever infection because of the defects of host defense or the adverse effects of antifungal agents. The major factors of the reason on the severity of the deep-seated mycosis depends on the pathogenesity and the drug resistance for antifungal agents in infected fungi. The clinical factors related with hosts defenses are important to the other reason on the severity. We investigated that the multiple drug resistant (MDR) mechanism may be one of the major roles plays in the azole resistant Candida albicans strains isolated form the patients with oropharyngeal candidiasis infected HIV. We analyzed which clinical factors are related with the prognosis of the patients with pulmonary cryptococcosis and aspergilloma. The titer of cryptococcal capsular antigen was earlier improve in the patient without underline disease than in the patients with underline diseases diagnosed pulmonary cryptococcosis. CRP was higher in the death cases in the patients with pulmonary aspergilloma, compared with alive cases.

AIDS-Related Opportunistic Infections↗
PubMed1998

[Assessment of the various image display systems affected to the visual analysis using 99mTc-GSA liver scintigraphy].

The aim of this study was to evaluate the physical performance for the gray-scale monitor and the image display system of the color monitor with the films using the visual analysis of the liver scintigraphy by 99mTc-DTPA-galactosyl-human serum albumin (GSA). The seven kinds of calibration curves (CC) were applied to convert into both the counts of the density of the films and the intensity of the monitors. The relationship between the intensity and density was evaluated in the 123 patients suspected with hepatic dysfunction. The liver scintigraphy images of 1-minute duration from five to six minutes after administration of 99mTc-GSA were converted according to the seven kinds of CC (861 images per image display system). These images were visually classified by the 16 observers following the five-point scoring system arranged beforehand. The intensity of monitors and the density of films showed positive correlation. Thus the CC for both the intensity and the density was centralized. The CC obtained by the present study was suitable for both monitors and films, respectively. The CC, which had the slope of approximately 4.8 for the monitor and 4.2 for the film, showed a good correlation between the indices of liver functions obtained from the biochemical liver function tests and from the 99mTc-GSA liver scintigraphy. Data suggest that the suitable CC in the three sets of image display system may contribute to the other scintigraphy as well as 99mTc-GSA liver scintigraphy, evaluating the scintigraphy using the visual analysis.

Adult↗
PubMed1998

[Characteristics of home care patients with intractable neurological diseases (Nanbyo) in Tokyo].

The purpose of this study was to identify the characteristics of home care of patients with intractable neurological diseases. A survey was conducted of members of Tokyo Medical Association who were home visit doctors. They responded to questions about their patients who have suffered from either Parkinson's disease (PD), spinocerebellar degeneration (SCD), or amyotrophic lateral sclerosis (ALS), and whose home care have been supported by the care system for at least three months. Of 205 survey questionnaires collected, 198 were effective to be analyzed. The sample consisted of 105 patients with PD (53.0%), 63 patients with SCD (31.8%), and 30 patients with ALS (15.2%). The mean age of the PD was 75.5 years with a range of 53 to 90, SCD was 66.5 years with a range of 39 to 88, and ALS was 58.7 years with a range of 42 to 86. The major findings in this study were as follows: 1) The patients who had one or more medical equipment installed at the beginning of home care were 30% of ALS, 9% of PD and 18% of SCD. As time elapsed, patients who needed to have some medical equipment installed increased in ALS greater than in PD and SCD. 2) The home doctors predicted that the condition of 37% of ALS patients, 9% of PD, and 8% of SCD would probably be deteriorating within one month. 3) Of the 30 patients with ALS, 47% experienced hospitalization three times or more compared to 27% of PD and 21% of SCD. The most prevalent reason for hospitalization for ALS was respite of caregivers, PD and SCD, however, were hospitalized for control of prescription, a change for the worse, or treatment of other diseases. 4) Ninety percent of ALS caregivers felt extremely tired or slightly tired. Their home doctors responded that 83% of ALS caregivers did their best in caregiving. 5) ALS patients utilized social resources such as volunteers, care workers, services of supply and maintenance of medical equipment, and emergency care for 24 hours more than SCD and PD. In the conclusion, ALS patients experienced the highest hospitalization of the three diseases and respite of family caregivers was necessary. They showed a higher utilization of various social resources than other diseases. It is important to consider these characteristics of home care patients by diseases in order to prepare and develop the necessary support system of home care for the intractable neurological patients.

Adult↗
PubMed1998

Induction of Fas-mediated apoptosis in a human renal epithelial cell line by interferon-gamma: involvement of Fas-mediated apoptosis in acute renal rejection.

To examine the role of the Fas ligand/Fas (FasL/Fas) system and apoptosis in renal allograft rejection, we analyzed FasL/Fas expression and apoptosis in 63 renal allograft biopsy specimens obtained from 56 renal transplant recipients in Tokyo, Japan. Sixteen biopsy specimens were diagnosed (Banff criteria) as acute rejection (AR), 17 as AR plus chronic rejection, 10 as borderline stages, and 20 as no rejection (NR). Immunohistochemically, Fas antigen was highly expressed in the renal tubular epithelium in tissues from patients with rejection. The mean number of Fas-positive tubular epithelium was significantly higher in biopsy specimens with AR than in those with NR, but FasL expression was highly expressed in infiltrating lymphocytes in the interstitium of allografts with cellular rejection. The mean number of FasL-positive infiltrating lymphocytes was significantly higher in specimens with AR than in those with NR or borderline stages. For detection of apoptotic cells, the specimens were subjected to terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling, which showed that the mean number of tubular epithelial cells positive for this labeling was highest for the specimens with AR, the number being significantly higher than in those with AR plus chronic rejection or with NR. Thus, Fas expression on epithelial cells might actively trigger their apoptosis by the interaction between Fas and FasL. Studies of human normal renal-derived cell lines (RPTEC 2601 [epithelial] and NHMC 5155 [mesangial]) showed that both constitutively expressed Fas (but not FasL) mRNA. After pretreatment with interferon-gamma, Fas-induced apoptosis was observed in the RPTEC 2601 line, but without interferon-gamma pretreatment, anti-Fas-mediated apoptosis was not seen. Under identical conditions, the NHMC 5155 line was resistant to anti-Fas-mediated apoptosis regardless of interferon-gamma pretreatment. This suggested that AR might be associated with increased apoptosis in the renal tubular epithelial cells mediated by the Fas/FasL system.

Acute Disease↗
PubMed1998

[Pneumonia caused by granulomatous Pneumocystis carinii in a patient with the acquired immunodeficiency syndrome].

A 54-year-old man was admitted to the hospital because of fever and general fatigue. A chest roentgenogram on admission showed lobular opacities and ill-defined opacities in both lower lobes. The pneumonia was successfully treated with antibiotics. The acquired immunodeficiency syndrome was diagnosed because ELISA and PCR tests for antibodies to the human immunodeficiency virus were positive and the CD 4+ lymphocyte count was 39 per cubic millimeter. Examination of bronchoalveolar lavage fluid revealed no Pneumocystis carinii. Trimethoprim and sulfamethoxazole were given prophylactically, but were withdrawn because of a rash. The patient began to receive aerosolized pentamindine and was discharged. On the next day, he was readmitted to the hospital because of a high fever. A chest roentgenogram showed diffuse miliary opacities. Chest CT scan also showed diffuse small nodular opacities in both lungs. Examination of a transbronchial biopsy specimen revealed well-defined, noncaseating granulomas with pneumocystis organisms in their centers. Cultures for tuberculosis and fungi were all negative. We diagnosed granulomatous pneumonia caused by Pneumocystis carinii, which is an atypical manifestation of Pneumocystis carinii pneumonia. The patient died of sepsis and cardiac tamponade. Microscopically, the lung tissue was found to have foamy intra-alveolar exdates, which is a typical histological feature of Pneumocystis carinii pneumonia.

AIDS-Related Opportunistic Infections↗
PubMed1998

[Pulmonary actinomycosis with "balls-in-a hole" appearance diagnosed by examination of bronchial lavage fluid].

A 49-year-old man was referred to our hospital because of abnormal chest X-ray findings. Chest X-ray films showed infiltrative opacities in the right lung, and histological findings of a transbronchial biopsy specimen showed non-specific inflammation. The patient was treated with Ofloxacin for one month. After the treatment, chest X-ray films showed that the infiltrative opacities in the right upper lobe had decreased, but that opacities in the right lower lobe had increased, with an air meniscus sign. A chest computed tomography scan at the same time revealed that the remaining opacities contained multiple mass-like lesions within a cavity in the right S6, appearing as "balls in a hole". One year after the first visit, the patient visited the hospital again because of cough and sputum. A chest X-ray film showed that the size of the cavity in the right lower lobe had increased. The histological findings from a fresh transbronchial biopsy specimen revealed a non-specific inflammation again; however, black clots obtained from bronchial lavage fluid after biopsy were histologically identified as sulfur granules, a classic pathological indication of actinomycosis. This confirmed the diagnosis of pulmonary actinomycosis. The patient was treated with penicillin, and the opacities in the right lower lobe subsided.

Actinomycosis↗
PubMed1998

[A case of malignant rheumatoid arthritis complicated by secondary amyloidosis and membranous nephropathy].

A 30-year-old man had been treated for malignant rheumatoid arthritis from 1989 with a non-steroidal anti-inflammatory drug, then bucillamine for six months and prednisolone. Mild proteinuria appeared in May 1994, 4 years after bucillamine therapy was conducted. The patient was admitted to our hospital for a renal biopsy in July 1994. The specimen revealed secondary amyloidosis and membranous nephropathy (MGN). These findings suggest that MGN unrelated to bucillamine therapy might have occurred with secondary amyloidosis in rheumatoid arthritis.

Adult↗
PubMed1997

Restricted TCR V alpha repertoire in the T cell response to a tolerogenic determinant of type II collagen.

Tolerization of B10.RIII mice (H-2r) with i.v.-injected type II collagen (CII) renders the animals resistant to induction of collagen-induced arthritis (CIA). The B10.RIII mouse is of particular interest, in that the T cell determinants that induce tolerance are different from those that induce arthritis. To characterize T cells that react with the tolerogenic determinant and play a role in regulation of arthritis, we have developed a panel of T cell hybridomas reactive with the tolerogenic T cell epitope, CII 607-621. None of the hybrids cross-reacted with either the arthritogenic CII 445-453 or murine CII. As determined by PCR and immunofluorescence, the T cell response to the tolerogenic determinant was oligoclonal, with evident preferential usage of V alpha. Through the analysis of a large panel of T cell hybridomas, preferential usage of V alpha2, J alpha44, J beta2.7, and D beta2.1 was observed. Characterization of T cells reactive with the immunodominant determinant, CII 607-621, responsible for the induction of tolerance should prove important in developing novel therapeutic approaches for the treatment of autoimmune diseases.

Amino Acid Sequence↗
PubMed1997

Functional expression and characterization of frog photoreceptor-specific calcium-binding proteins.

S-modulin (sensitivity-modulating protein) is a photoreceptor-specific calcium-binding protein which plays an important role in the light adaptation process by controlling rhodopsin phosphorylation in rods. S-modulin and its cone homologue, s26, were expressed at high level (more than 30% of total protein) in Escherichia coli and then purified. They both inhibited rhodopsin phosphorylation in a calcium dependent manner. Myristoylated recombinants of S-modulin and s26 showed calcium-dependent changes in tryptophan emission spectra with half-maxima at about 0.7 microM free calcium concentration. However, the spectral changes are distinctive from each other, suggesting that there is some difference in the structural change between S-modulin and s26.

Adenosine Triphosphate↗
PubMed1997

Comparison between Wako-WB003 and Fungitec G tests for detection of (1-->3)-beta-D-glucan in systemic mycosis.

The limulus factor G reacts with (1-->3)-beta-D-glucan, a major structural component of fungal cell walls. The Fungitec G test is a colorimetric assay that measures the concentration of (1-->3)-beta-D-glucan and is used as a serodiagnostic test for deep mycosis. Wako-WB003 is another assay for (1-->3)-beta-D-glucan that determines the change in turbidity of the gelatin reaction of limulus factor G with (1-->3)-beta-D-glucan. In five rabbits inoculated intravenously with 1 x 10(7) CFU of Candida albicans, the concentration of (1-->3)-beta-D-glucan measured by the fungitec G test increased gradually reaching a peak of 660.9 +/- 427.9 pg/ml (mean +/- SD) 4 days after inoculation, but to 42.225 +/- 41.275 ng/ml on day 6 in the Wako-WB003 test. In one rabbit challenged intravenously with 5 x 10(6) CFU of C. albicans, (1-->3)-beta-D-glucan increased to 101.5 pg/ml on day 4 on the fungitec G test, whereas the level remained below the detection limit of the Wako-WB003 test throughout the course of the disease. We also detected high concentrations of (1-->3)-beta-D-glucan in 11 patients with candidemia, 4 with suspected candidemia, 1 with invasive pulmonary aspergillosis, and 12 patients with aspergilloma. The concentration of (1-->3)-beta-D-glucan measured by the Fungitec G test was > 150, > 1006.8; 312.1, and 55.6 +/- 37.4 pg/ml (range, 20.1-138.0 pg/ml), and by the Wako-WB003 test > 153.000, > 17.70, 153.000 and 2.645 +/- 7.248 ng/ml (range, < 25.20 ng/ml) in these patients, respectively. In contrast, the concentration of (1-->3)-beta-D-glucan in 9 patients with pulmonary cryptococcosis and 6 with superficial candida colonization ranged from < 13.2 and < 15.3 pg/ml in the Fungitec G test and < 0.53 and < 0.12 ng/ml in Wako-WB003 test. There was a weak relationship between the concentration of (1-->3)-beta-D-glucan measured by the Fungitec G test and Wako-WB003 test (r = 0.521). Our results indicate that the sensitivity of the Wako-WB003 test is lower than that of the Fungitec G test.

Animals↗