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Biomedical subjects

T Hirose

Publications and source records attributed to T Hirose.

At least 433 records · Page 24Linked to original sources
PubMed1992

Effect of stimulus contrast on simultaneous steady-state pattern reversal electroretinogram and visual evoked response.

We studied the effect of stimulus pattern contrast on the simultaneously recorded pattern reversal electroretinogram (PERG) and pattern reversal visual evoked response (PVER) at 5 check sizes. The stimulus contrast ranged from 24 to 95% in 6 steps of 0.1- or 0.15-log unit increments. PERG amplitude showed a linear increase with an increase in pattern contrast at all check sizes. PVER amplitude showed an increase up to a certain pattern contrast, but was saturated upon further increase in stimulus contrast at all check sizes. The PERG amplitude-check size function curve showed a flattened, inverted-U shape only with the highest contrast and low-pass filter shape or flat shape with lower contrasts. The PVER amplitude-check size function curve showed an inverted-U shape (bandpass filter shape) at all contrasts. These characteristics to the changes in contrast and the spatial frequency tuning suggest that PVER is processed in a different location of visual pathway than PERG.

Adult↗
PubMed1992

Pretreatment with aerosolized capsaicin potentiates histamine-induced bronchoconstriction in guinea pigs.

The aim of the present study was to examine whether endogenous neuropeptides released from sensory nerves can potentiate airway responsiveness to histamine. Total pulmonary resistance (RL) was measured to assess the bronchial responsiveness to increasing doses of histamine (1.25, 2.5, 5, and 10 micrograms/kg) administered intravenously in 29 anesthetized and artificially ventilated guinea pigs. Pretreatment with aerosolized capsaicin (3 micrograms/ml for 15 to 60 s) 30 min before obtaining the dose-response to histamine significantly potentiated percent increase in RL caused by each dose of intravenously administered histamine. Pretreatment with substance P (0.5 ml/kg of 10(-5) M) administered intravenously also potentiated the airway responsiveness to histamine. As assessed by the amount of extravasation of Monastral blue pigments, both capsaicin aerosol and substance P injected intravenously induced increased vascular permeability in the tracheal mucosa. These findings suggest that endogenous neuropeptides, especially tachykinin such as substance P, can induce airway hyperresponsiveness to nonspecific stimuli and play a possible role in producing airway hyperresponsiveness in bronchial asthma.

Aerosols↗
PubMed1992

[Effects of nutritional status on contents of tryptophan, serotonin and 5-hydroxyindoleacetic acid in rat brain].

Effects of nutritional status on the levels of tryptophan (Trp), serotonin (5HT), and its metabolite, 5-hydroxyindoleacetic acid (5HIAA) in six brain regions of rats were investigated. 1) A low-protein high-carbohydrate diet decreased Trp, 5HT and 5HIAA levels in the cortex and hippocampus, and those of 5HT and 5HIAA in the hypothalamus. This diet did not affect the contents of Trp and 5HT in the midbrain, but decreased 5HIAA. No significant changes of Trp, 5HT and 5HIAA were observed in the pons and medulla and striatum. 2) A low-carbohydrate high-protein diet increased the levels of Trp, 5HT and 5HIAA in the striatum, and 5HT and 5HIAA in the cortex, but showed no effect on the contents of Trp, 5HT and 5HIAA in the hippocampus, midbrain, pons and medulla and hypothalamus. 3) An energy-restriction low-carbohydrate diet increased Trp, 5HT and 5HIAA contents in the striatum, and 5HT and 5HIAA in the cortex and pons and medulla. In the hypothalamus, only 5HIAA was increased by this diet. The diet did not influence Trp, 5HT and 5HIAA contents of the midbrain and hippocampus. These results suggest that i) lowered fat and carbohydrate intakes enhance 5HT synthesis and metabolism in the cortex and that lowered carbohydrate intake enhances them in the striatum, ii) energy restriction enhances the 5HT metabolism in the cortex, pons and medulla and hypothalamus, and 5HT synthesis in the cortex and pons and medulla, iii) lowered protein intake inhibits 5HT metabolism in the cortex, midbrain, hippocampus and hypothalamus, and 5HT synthesis in the cortex, hippocampus and hypothalamus.

Animals↗
PubMed1992

Antitumor activity of Toxoplasma lysate antigen against methylcholanthrene-induced tumor-bearing rats.

Growth of the tumor autoinduced by 20-methylcholanthrene (MC) in rats was inhibited after administration of Toxoplasma lysate antigen (TLA). The antitumor activity of TLA was most obvious in the early stage of tumoral growth. When TLA was administered to rats before the appearance of tumour, tumor formation was delayed slightly. Histopathological studies revealed dense growths of spindle tumor cells in untreated control rat, while enlarged central necrosis with the infiltration of lymphocytes and neutrophils was apparent in TLA-treated rats. According to the immunohistological examination of tumor tissue with anti-Thy-1 antibody, the rats treated with TLA showed large Thy-1 positive granular cells, whereas the untreated rats indicated only a few small Thy-1 positive cells. These observations indicate that TLA is a useful modifier of biological responses to MC-induced tumors.

Animals↗
PubMed1992

Role of adherent spleen cells in the induction of cytotoxic activity by Toxoplasma lysate antigen.

In order to identify mechanisms responsible for the anti-tumor effects of Toxoplasma lysate antigen (TLA), we used an in vitro 51Cr release assay to study the functional properties of plastic-adherent cells during induction of splenic cytotoxic activity by TLA. Cytotoxic activity of non-adherent cells was measured in all experiments after a 6 days incubation. Induction of cytotoxic non-adherent cells by TLA required the presence of plastic-adherent spleen cells. In contrast, rhIL-2 alone was able to induce transformation of cytotoxic non-adherent cells from non-adherent spleen cells. Contact between adherent and non-adherent spleen cells was necessary for successful induction of cytotoxic non-adherent cells by TLA. Treatment of spleen cells with anti-macrophage serum prevented induction of cytotoxic activity by TLA. Biologically active IL-2 was not detected in culture supernatants of spleen cells exposed to TLA. These findings suggest that contact between TLA-sensitized non-adherent cells and macrophages is necessary for induction of cytotoxic cells in the presence of TLA. This contact, however, is not necessary for generation of IL-2-induced killer cells.

Animals↗
PubMed1992

Therapeutic effects of Toxoplasma lysate antigen on 20-methylcholanthrene-induced BALB/c mouse tumors.

Therapeutic effects of Toxoplasma lysate antigen (TLA) were studied in mice bearing the tumor in the second passage of 20-methylcholanthrene (MC)-induced tumor cells. Intramuscular administration of TLA 7 days after the tumor-cell inoculation caused apparent inhibition of the tumor growth on day 14. The second treatment facilitated the therapeutic effects. Intravenous transfer of spleen cells prepared from TLA-sensitized mice into tumor-bearing mice also represented the growth inhibitory effects. Prominent effects were seen when the transferred cells were prepared 5 days after sensitization of donor animals. The inhibitory effects were absent in the groups transferred only the adherent cells or the non-adherent cells prepared from sensitized mice. The strongest inhibitory effect was observed in the group to which both adherent and non-adherent spleen cells were transferred simultaneously from sensitized mice. In in vitro experiments, spleen cells obtained from sensitized mice showed cytolytic effect on P-815 or YAC-1 cells after the secondary stimulation in vitro with TLA. Large non-adherent cells containing densely packed granules were induced when cultured with the adherent cells obtained from sensitized mice. These results revealed that TLA can inhibit the growth of the chemically-induced transplantable tumors by activation of adherent and non-adherent spleen cells.

Animals↗
PubMed1992

Characteristics of cytotoxic cells induced by Toxoplasma lysate antigen in mouse spleen.

Spleen cells from Toxoplasma lysate antigen (TLA)-sensitized BALB/c mice showed the strong cytotoxic activity against both natural killer (NK)-sensitive cells (YAC-1 and RL male-1) and NK-insensitive cells (P-815), when incubated with TLA or recombinant human IL-2 (rhIL-2). The increment of TLA concentration in culture medium increased the cytotoxic activity. Treatment of effector cells; spleen cells from TLA-sensitized mice incubated with TLA, with anti-asialo GM1 or anti-Thy-1 plus complement inhibited the cytotoxic activity of effector cells, whereas treatment with anti-mouse Lyt-2.2 serum plus complement had no effect on the cytotoxic activity. Treatment of spleen cells from TLA-sensitized mice with anti-asialo GM1 and/or anti-Thy-1 plus complement inhibited cytotoxic activities of effector cells. These results suggested that spleen cells sensitized with TLA both in vivo and in vitro were asialo GM1 positive and Thy-1 positive, and the majority of cytotoxic cells induced by TLA were similar to lymphokine-activated killer (LAK) cells induced by IL-2.

Animals↗
PubMed1992

Hashimoto's thyroiditis in HTLV-I carriers.

We describe two HTLV-I virus carriers who have biopsy-proven Hashimoto's thyroiditis. The first patient, a 64-year-old female, has had goiter and hypothyroidism since the age of 56. The second patient, a 66-year-old male, developed hyperthyroidism and goiter at the age of 44, but at present he is hypothyroid. Both patients are positive for anti-thyroid antibodies and anti-HTLV-I virus antibody. Findings of the thyroid biopsy specimens were consistent with Hashimoto's thyroiditis. These data suggest that Hashimoto's thyroiditis develops in HTLV-I carriers who have no clinical evidence of HAM/TSP.

Aged↗
PubMed1992

[Methicillin-resistant Staphylococcus aureus (MRSA) infection in urological field--clinical backgrounds and clinical course].

The Staphylococcus aureus in this study were isolated from 33 outpatients and 38 inpatients of the Department of Urology from August 1989 to April 1991. Twenty one patients (29.5%), three outpatients, had the MRSA type. Significant correlations were found between the incidence of MRSA infection and such factors as diabetes mellitus and the isolation of MRSA within 7 days of the administration of antibiotic agents. Out of 14 MRSA which were investigated for coagulase type, 9 were type VII. This indicates an outbreak of MRSA in the urological ward. Seven cases of MRSA and 5 cases of MRSA had high grade fever (over 38 degrees C), but all patients experienced much relief by using susceptible antibiotic agents. Our study shows that the isolation frequency of MRSA has increased in urological field. Therefore, we think it is important to treat patients with MRSA infection adequately, especially when there are compromised hosts in the same room.

Adult↗
PubMed1992

[Effects of prostaglandin E1 and dibutyryl cyclic AMP on hemodynamics after cardiopulmonary bypass in valve replacement surgery].

In view of vasodilating action of prostaglandin E1 (PGE1) and dibutyryl cyclic AMP (DBcAMP) we investigated the effect of each agent on hemodynamics after weaning from cardiopulmonary bypass (CPB) comparing with the effect in control group. PGE1 and DBcAMP were administered to patients who underwent valve replacement surgery with continuous low dose infusion at an average rate of 0.026 micrograms.kg-1.min-1 and 7.25 micrograms.kg-1.min-1 respectively. Following result was obtained. In PGE1 administered group, a significant reduction in pulmonary vascular resistance (PVR) and a significant decrease in mean arterial pressure (MAP) were observed during CBP, while there were no significant differences in other parameters, such as platelet counts, differences between core and peripheral temperature (delta T), urine output, systemic vascular resistance (SVR), cardiac index (CI), right-to-left shunt (Qs/Qt), oxygen delivery (DO2) and oxygen consumption (VO2). However, CI and platelet counts tended to increase but delta T and SVR tended to decrease. In DBcAMP administered group, there were no significant differences in all parameters compared with those of control group, showing a tendency of less improvement in hemodynamics than in PGE1 group. We have shown that the use of PGE1 rather than DBcAMP as vasodilator agent seems advantageous during open-heart surgery in patients especially with severe pulmonary hypertension, but it tends to cause severe hypotension during CPB.

Aged↗
PubMed1992

Characterization of type V collagenase (gelatinase) in synovial fluid of patients with inflammatory arthritis.

Gelatin degrading matrix metalloproteinases in synovial fluid from 21 patients with inflammatory arthritis were shown to consist of two distinct gene products, 92 and 70 kDa gelatinases. The gelatinolytic activity of 92 kDa enzyme, which is released from stimulated neutrophils, was positively correlated to neutrophil count in the fluid. By contrast, 70 kDa molecule did not correlate with neutrophil cell count. Purification of these enzymes revealed they could degrade type XI collagen, a cartilage component resistant to interstitial collagenase. The elevated levels of 92 kDa gelatinase in rheumatoid arthritis samples compared to osteoarthritis suggest a role of this enzyme in cartilage destruction.

Adult↗
PubMed1992

[Reconstruction of anterior cranial base and face with free musculocutaneous flap; report of two cases].

The treatment of extensive cranial base tumor is still challenging. Wide resection of a cranial base tumor would lead to exposure of the vital structures such as the brain and dura, and would result in a large dead space in the cranium and in the connecting area between the nasal cavity and the intracranial space. Recently free tissue transfer has become a reliable method in the field of reconstructive surgery. In the craniofacial region, free tissue transfer is useful to reconstruct a complicated defect. We report two cases where free latissimus dorsi M-C flap and rectus abdominis M-C flap were useful in reconstructing the defect following removal of an anterior cranial base tumor. We discuss the advantages.

Aged↗
PubMed1992

Cytokine regulation of prolyl 4-hydroxylase production in skin fibroblast cultures from patients with systemic sclerosis: contribution to collagen synthesis and fibrosis.

Prolyl 4-hydroxylase (PH) is an enzyme that catalyzes an essential step in procollagen synthesis. PH production, as measured by the new ELISA method, was significantly higher in fibroblast cultures from patients with systemic sclerosis (SSc; N = 7) than in cultures from healthy controls (NC; N = 5) (p less than 0.01). Transforming growth factor-beta and tumor necrosis factor-alpha significantly increased PH production, but recombinant interferon-gamma had a significant negative effect on PH production. Since the production of PH is relevant to collagen synthesis by fibroblasts of patients with SSc, regulation of PH production may have therapeutic value.

Cells, Cultured↗
PubMed1992

[An autopsy case of malignant rheumatoid arthritis (MRA) which was difficult to distinguish from polyarteritis nodosa (PN)].

We encountered a patient who was diagnosed as rheumatoid arthritis (RA) at 15 years old and developed malignant RA (MRA) within one year. He suffered from mononeuritis multiplex and cutaneous infarction. Despite of treatment including steroid pulse therapy, neuritis progressed. Lung infiltration, pancreatitis and intestinal bleeding were accompanied. He died of disseminated intravascular coagulation on 153 days after admission. Autopsy revealed systemic rheumatoid vasculitis in coronary artery, pancreas, liver, small and large intestine, kidney and lung. These severe vasculitis occurred in young RA patient are rare case and it is important to consider the therapy and prognosis.

Adolescent↗
PubMed1992

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from urinary tract infections (1988). I. Susceptibility distribution].

Isolation frequencies and sensitivities to antibacterial and antibiotic agents were investigated on 801 bacterial strains isolated from patients with urinary tract infections in 9 hospitals during the period of June to November 1988. Of the above total bacterial population, Gram-positive bacteria accounted for 29.3% and a majority of them were Enterococcus spp. Gram-negative bacteria accounted for 70.7% and most of them were Escherichia coli. 1. Enterococcus faecalis: Vancomycin was most active with its MIC90 < or = 0.78 microgram/ml. Ampicillin, piperacillin, ofloxacin (OFLX), ciprofloxacin (CPFX) and imipenem (IPM) were also active. 2. Staphylococcus aureus: Arbekacin and minocycline were most active with their MIC90s 0.39 microgram/ml and 1.56 micrograms/ml, respectively. Among penicillins, dicloxacillin was the most active. Activities of cephems were considerably lower. 3. E. coli: Most of the agents were tested active. Particularly the second and third generation cephems were active in a range of < or = 0.10-0.20 microgram/ml. Carumonam (CRMN), IPM, OFLX and CPFX were also active with MIC90s < or = 0.10 microgram/ml. 4. Klebsiella pneumoniae CRMN and IPM were highly active. Penicillins generally showed lower activities. Cephems and new quinolones had high activities with their MIC90s in a range of 0.39-0.78 microgram/ml. 5. Proteus mirabilis: The third generation cephems were active with their MIC90s in a range of < or = 0.10-0.20 microgram/ml. CRMN, OFLX and CPFX were also active with their MIC90s < or = 0.10 microgram/ml, 0.39 microgram/ml and 0.20 microgram/ml, respectively. 6. Pseudomonas aeruginosa: IPM and tobramycin were active with their MIC90s 1.56 micrograms/ml and 3.13 micrograms/ml, respectively. CRMN and new quinolones showed MIC80s of 25-100 micrograms/ml. Most of penicillins and cephems were not active. 7. Other Gram-negative rods: Against Citrobacter freundii, Enterobacter cloacae and Serratia marcescens, IPM, CPFX and OFLX were active. Penicillins and cephems were not so active. CRMN was active against S. marcescens with its MIC80 at 6.25 micrograms/ml.

Anti-Bacterial Agents↗
PubMed1992

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from urinary tract infections (1988). II. Background of patients].

Clinical background was investigated on 916 bacterial strains isolated from patients with urinary tract infections (UTIs) in 9 hospitals during the period from June to November, 1988. 1. Distribution of sexes, ages and infections: Among males, fifties and older were most frequent and most of them had complicated UTIs. Among females, most cases among twenties or thirties were uncomplicated UTIs. Forties and older cases were most frequent and complicated UTIs were more frequent among them than among patients in twenties and thirties. 2. Distribution of sexes, ages and pathogens isolated from UTIs: In males, Pseudomonas spp. and Enterococcus spp. were frequently isolated. In contrast, in females, Escherichia coli was the most frequent. In thirties, E. coli was not the most frequently isolated bacterium. Frequency of Pseudomonas spp., other non-fermented Gram-negative rods and Enterococcus spp. were greater among patients with higher ages. 3. Administration of antibiotics and pathogens isolated from UTIs: (1) Before administration: In uncomplicated UTIs, E. coli accounted for the majority of causative organisms. In complicated UTIs, particularly in those cases with indwelling catheter, Enterococcus spp. and Pseudomonas spp. were rather frequently isolated. (2) After administration: In complicated UTIs, higher number of pathogens were isolated. Pseudomonas spp. and Enterococcus spp. were the most frequent. Distribution of pathogens isolated from complicated UTIs without indwelling catheter was similar to that before antibiotic administration.

Adult↗
PubMed1992

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from urinary tract infections (1988). III. Secular changes in susceptibility].

Sensitivities to various antibacterial and antibiotic agents of strains of Escherichia coli, Klebsiella spp., Proteus spp., Citrobacter spp., Enterobacter spp., Serratia marcescens and Pseudomonas aeruginosa isolated from patients with urinary tract infections (UTIs) in 9 hospitals during June to November 1988 were compared with those in the same period of previous year according to a classification, uncomplicated UTIs, complicated UTIs without indwelling catheter, and complicated UTIs with indwelling catheter. No remarkable changes were found in sensitivities of E. coli, Proteus spp., Citrobacter spp. and S. marcescens. The sensitivity of Klebsiella spp. to cephems decreased in complicated UTI without indwelling catheter and increased in complicated UTI with indwelling catheter. The sensitivity of Enterobacter spp. to third generation cephems decreased in complicated UTI with indwelling catheter. Sensitivities of P. aeruginosa to aspoxicillin and cefsulodin increased. The number of resistant strains to new quinolones increased slightly.

Anti-Bacterial Agents↗