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Biomedical subjects

T Uzawa

Publications and source records attributed to T Uzawa.

At least 19 recordsLinked to original sources
PubMed1995

Comparison of the effects of intermittent and continuous administration of human parathyroid hormone(1-34) on rat bone.

We compared the effects of synthetic human parathyroid hormone (1-34) (hPTH[1-34]) on rat bones when administered by intermittent injection and by continuous infusion for 4 weeks. Continuous infusion of hPTH(1-34) caused a dose-dependent decrease in the dry weight of the femur and a hyperparathyroidism-like condition in the high-dose group (214 ng/kg/h). In this group, although bone morphology was quite abnormal, the metaphyseal trabecular bone volume increased, whereas the epiphyseal trabecular bone volume tended to decrease, enhancing both bone resorption and formation. The diaphyseal cortical bone of the tibia became markedly porous, and this appeared to be the main cause of the decrease in total bone weight. Conversely, the dry weight of the femur increased in a dose-dependent manner in the intermittent-injection groups. Neither porosity of the cortical bone nor abnormal morphology of the trabecular bone was observed. The volume of the metaphyseal trabecular bone increased while retaining its normal morphology. The epiphyseal trabecular bone formation obviously increased without increase in the number of osteoclasts. In other words, it was postulated that the total weight of bone increased because intermittent injection of hPTH(1-34) increased the trabecular bone volume without loss of the cortical bone volume. These results show that either mode of treatment with hPTH(1-34) continuously accelerated bone formation, whereas the continuous infusion was essential for persistently and markedly enhanced acceleration of bone resorption. It appears that the increase in bone volume with intermittent injection of hPTH(1-34) resulted from the prominent manifestation of its bone-formative action rather than from its bone-resorptive action.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1994

Efficacy of recombinant human granulocyte-macrophage colony-stimulating factor for chemotherapy-induced leukopenia in patients with non-small-cell lung cancer.

To assess the feasibility and efficacy of rhGM-CSF in ameliorating chemotherapy-induced leukopenia in patients with advanced non-small-cell lung cancer, we conducted a double-blind placebo controlled phase III study in a multicenter setting. Patients were eligible if they had cytologically or histologically proven cancer, no prior chemotherapy, stage IIIB or IV disease, an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, an age of less than 76 years, and no symptomatic brain metastasis, disseminated bone metastasis, or previous vertebral/pelvic irradiation. The chemotherapy regimen consisted of mitomycin given at 8 mg/m2 on day 1, cisplatin given at 100 mg/m2 on day 1, and vindesine given at 3 mg/m2 i.v. on days 1 and 8 (MVP). If the granulocyte nadir count recorded after the first cycle of MVP was less than 1,000/mm3, patients were randomly assigned to receive recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) or placebo during the second cycle of MVP. The dose of rhGM-CSF was 125 micrograms/m2 given daily s.c. for 14 consecutive days starting on day 2. Of the 52 patients enrolled, 45 were evaluable. The nadir of granulocytes was significantly lower in the placebo group (P = 0.007). The period during which the granulocyte count was less than 1,000/mm3 was significantly longer in the placebo group (median, 6 vs 10 days; P = 0.04). The incidence of adverse effects related to rhGM-CSF, such as fever (> or = 38 degrees C) and skin rash, was significantly higher in the rhGM-CSF group (P = 0.011). The rate of response to chemotherapy did not significantly differ between the two groups. In conclusion, rhGM-CSF reduced the duration of chemotherapy-induced granulocytopenia. The clinical usefulness of this agent may be deminished because of the adverse effects encountered when it is used in combination with a moderately myelotoxic chemotherapy regimen.

Adult↗
PubMed1994

Effects of unusual polyamines on phenylalanyl-tRNA formation.

The effects of novel polyamines on aminoacyl-tRNA formation catalyzed by Escherichia coli., Sulfolobus acidocaldarius, and Thermus thermophilus HB8 S-100 extracts were investigated. These effects were diverse and differed depending on the amino acid and the enzyme used. A quaternary polyamine, tetrakis(3-aminopropyl)ammonium, inhibited phenylalanyl-tRNA synthesis catalyzed by the T. thermophilus extract, but not inhibit the other aminoacyl-tRNA formations tested. The inhibition was observed in hybrid reactions where the thermophile tRNA or extract was replaced by its E. coli counterpart, although the quaternary amine did not inhibit Phe-tRNA formation by the E. coli homologous system. Spermine relieved the inhibition of the reaction of thermophile enzyme and tRNA, but not the inhibition of the hybrid reactions. These results suggest that the branched polyamine interacts with both the thermophile enzyme and tRNA(Phe).

Biogenic Polyamines↗
PubMed1993

Effects of novel polyamines on cell-free polypeptide synthesis catalyzed by Thermus thermophilus HB8 extract.

Effects of novel, naturally occurring polyamines on protein synthesis catalyzed by Thermus thermophilus cell-free extract were investigated. The results revealed the physiological importance of a branched quaternary polyamine, tetrakis(3-aminopropyl) ammonium, in thermophile protein biosynthesis. Longer polyamines than triamine supported the polypeptide synthesis at high temperature, though both the activity and the optimum temperature varied depending on polyamines added. The highest activity was found when tetrakis(3-aminopropyl)ammonium and a tetraamine were simultaneously present. The optimum temperature of the reaction supported by the combination of the branched polyamine and spermine was the highest and in accord with the optimum temperature of the bacterial growth. These results suggested an essential role of the quaternary amine in protein synthesis in vivo. This amine effectively stabilized the ternary complex between ribosomes, the messenger, and phenylalanyl-tRNA, and this stabilization may account, at least in part, for its action on the present reaction. In contrast, another branched polyamine, tris(3-aminopropyl)amine supported the activity only moderately even in the presence of another polyamine, though the tris amine stabilized the ternary complex as effectively as the quaternary amine. This result suggests the presence of another essential site for polyamine action in the thermophile polypeptide synthesis, in addition to the stabilization of the ternary complex. The effects of polyamines on MS2 RNA directed reaction resembled those on poly(U) directed polypeptide synthesis, indicating that polyamines are essential in protein biosynthesis directed by natural messengers in vivo. The quaternary amine inhibited the aminoacylation of tRNA(Phe), and the inhibition was canceled by the addition of another polyamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Acylation↗
PubMed1993

Effects of polyamines on a continuous cell-free protein synthesis system of an extreme thermophile, Thermus thermophilus.

A continuous cell-free protein synthesis system of an extremely thermophilic eubacterium, Thermus thermophilus HB27, was constructed. This system produced MS2 phage RNA translation products at a rate of more than 5 micrograms per hour per 1.9 mg of ribosomes at 65 degrees C and the production continued linearly for at least 340 min. When no polyamine was added, the system did not produce the proteins. The highest activity was recorded when 0.1 mM tetrakis(3-aminopropyl)ammonium and 1.0 mM spermine were added simultaneously.

Bacterial Proteins↗
PubMed1993

[Clinical studies on ceftriaxone in respiratory tract infections. CTRX Study Group].

We report that the results of clinical studies on ceftriaxone (CTRX) in respiratory tract infections (RTIs). Clinical efficacies and side effects of CTRX were as follows; 1. Clinical efficacies of CTRX in a total of 61 cases with RTIs were excellent in 11 cases, good in 23, fair in 11, poor in 12 and unknown in 4. Thus the overall clinical efficacy rate was 59.6%. In cases of patients with lung cancers, the efficacy rate was 42.9%. 2. Clinical efficacy rates with once daily dosage were 50.0% with a dose level of 1 g CTRX and 54.8% with that of 2 g CTRX. 3. Side effects were observed in 2 cases (3.1%) and laboratory abnormalities were observed in 1 case (1.6%). They were not serious, however. These data suggest that CTRX is one of the useful cephalosporins in treatment of RTIs.

Adult↗
PubMed1992

A new method for assessment of marginal sealability of dental restorations.

A new testing system was developed for assessment of marginal sealability of dental restorations. It was constructed with a thermocycle loading line and a leakage detecting line partitioned from each other by the restoration under evaluation. The hot and cold solutions of rhodamine B as a tracer were alternately circulated in the thermocycle loading line by the switching of six solenoid valves. Marginal leakage of the tracer into distilled water circulating in the detecting line was periodically monitored by a spectrometer while thermocycling the restoration. The leakage data could be analyzed on the basis of an empirical formula. In application of this method, the durability of a complete seal against thermal changes was estimated on three teeth each of which was restored with an inlay, an amalgam or a glass ionomer.

Animals↗
PubMed1991

[Assessment of the permeability of the pulmonary microvasculature using radiotracers in a case of adult respiratory distress syndrome].

A 48-year-old man with small cell lung cancer developed ARDS, and massive pulmonary edema fluid was obtained with the fiberoptic bronchoscopy. The pulmonary edema fluid to serum ratios of total protein and albumin were 0.72 and 0.85 respectively. The ratio of LDH was higher (2.71), while that of cholesterol was lower (0.11) than that of total protein. Simultaneously, isopropyl N [I-123] p iodoamphetamine (I-123 IMP) and I-131 human serum albumin (I-131 HSA) were injected into this patient. Samples of blood and pulmonary edema fluid were collected to measure the clearance through the pulmonary microvasculature. The time activity curves of I-123 IMP and I-131 HSA in his blood samples revealed almost constant radioactivity from 5 minutes to 120 minutes after injection, while both radioactivity levels in pulmonary edema fluid samples increased with time. The clearance ratio of I-123 IMP to I-131 HSA was constant at each sampling time (mean +/- SD, 1.51 +/- 0.32). The linear correlation between I-123 IMP clearance and I-131 HSA clearance (r = 0.95, p less than 0.01) suggested that the clearance ratio of exudative plasma components may remain unchanged even if pulmonary microvasculature permeability has changed.

Body Fluids↗
PubMed1990

[Double filtration plasmapheresis in case of Goodpasture's syndrome].

This article describes a case of Goodpasture's syndrome controlled by double filtration plasmapheresis (DFPP) combined with steroid and immunosuppressant therapy. A 48-year-old male, clerk, complaining of fever, dry cough and macroscopic hematuria, was admitted to our hospital. Microscopic hematuria was first pointed out at age 40 on an annual check up. His laboratory data on admission revealed severe anemia, azothemia, macroscopic hematuria and proteinuria. His chest radiograph and CT revealed diffuse nodular densities in bilateral lung fields. Specimens obtained by transbronchial lung biopsy and open renal biopsy revealed linear deposition of IgG by direct immunofluorescent antibody methods. Circulating antiglomerular basement membrane antibody level determined with radioimmunoassay was 1.8% on admission, but one week later it elevated to 5.6% with progression of dyspnea, hypoxemia, and renal failure. Steroid pulse therapy and a total of 6 double filtration plasmaphereses were performed in the first month. Subsequently hypoxemia and dyspnea disappeared, and the chest radiograph of the 40th hospital day showed no abnormal shadows. Two months later recurrence of pulmonary hemorrhage was noticed. Immunosuppressant administration (Cyclophosphamide 100 mg/day) and a total of 10 DFPP procedures were performed with success. By DFPP, circulating anti-GBM antibody fell rapidly to within normal ranges, and anti-GBM antibody level elevated in removed plasma. We think DFPP is effective to remove circulating anti-GBM antibody in Goodpasture's syndrome.

Anti-Glomerular Basement Membrane Disease↗
PubMed1989

Structure-activity relationship of calcitonin gene related peptide.

Chicken, human(alpha) CGRPs and their analogues were synthesized to investigate the relationship between structure and serum calcium and phosphate lowering effects. The native hormones contain 37 amino acid residues with only four positions (3, 14, 15 and 23) that differ. Chicken CGRP exhibits stronger and longer lasting activities than the human hormone. A chicken CGRP analogue with replacement of Asp at position 14 by Gly (as in human CGRP) showed great reduction of activity. The converse replacement of Gly at position 14 by Asp in human CGRP enhanced this analogue activity. Among the synthetic analogues, des-1-Ala-des-alpha-amino chicken CGRP, exhibited the most potent and long lasting biological activity.

Amino Acid Sequence↗
PubMed1989

[Effects of monomer compositions on the bond strength of experimental light-cured 3-MBA resins to tooth substrates].

An adhesion promoting monomer of 3-methacryloyloxybenzoic acid (3-MBA) was utilized as an ingredient of experimental dental photocurable bonding resins. Effects of the monomer compositions of the resins on the bond strength to tooth substrates were examined. The bond strength of the light-cured resin was enhanced by the addition of 3-MBA. When 3-MBA was incorporated with Bis-MPEPP2.6E, TEGDMA or their binary comonomers, the bond strengths obtained were ca. 130 kgf/cm2 for the enamel treated with an aqueous solution of 10% citric acid and 3% FeCl3 and ca. 50 kgf/cm2 for the dentin. SEM examination revealed that the acid resistant dentin layer was formed by the infiltration and polymerization in situ of the monomer of the 3-MBA bonding resin. However, bond strengths of less than 50 kgf/cm2 obtained on treated dentin could be explained by the extent of the tag formation in dentinal tubules.

Acrylic Resins↗
PubMed1989

[An early stage case of pulmonary lymphangiomyomatosis].

A 35-year-old unmarried woman was admitted to our hospital because of right pneumothorax. Pulmonary lymphangiomyomatosis was suspected from CT and transbronchial lung biopsy findings. The diagnosis was confirmed histologically by open lung biopsy. As her biopsy specimen showed positive findings for both estrogen and progesterone receptor, tamoxifen administration was started. The CT revealed multiple cystic lesions (5-10 mm in diameter) but otherwise normal vascular structures and normal lung density. The plain chest radiograph showed no abnormalities. CT is very useful for the early detection of pulmonary lymphangiomyomatosis.

Adult↗
PubMed1988

Effect of human parathyroid hormone (PTH(1-34)) on experimental osteopenia of rats induced by ovariectomy.

The effect of human PTH(1-34) on the development of osteopenia induced by ovariectomy was investigated in immature female Sprague-Dawley rats. After the surgery, human PTH(1-34) was injected subcutaneously three times a week for 25 weeks. A reduction of serum calcium level and a tendency to increased serum alkaline phosphatase activity were seen in ovariectomized rats. The ovariectomized rat bones were characterized by reduction of dry weight, ash weight, calcium content and phosphorus content, but there was no change in length, volume and ash content in these bones. Human PTH(1-34) prevented the reduction of dry weight, ash weight, calcium content and phosphorus content dose dependently (1.5-6.0 micrograms/kg) in ovariectomized rats. It was concluded that pulsatile administration of human PTH(1-34) prevented the development of osteopenia induced by ovariectomy.

Alkaline Phosphatase↗
PubMed1988

[Esophageal cancer developing 13 years after radiotherapy of lung cancer].

This paper reports on an autopsied case manifesting an esophageal cancer that had developed 13 years after radiotherapy for lung cancer. The patient was a 61-year-old man. He was found to have a squamous cell carcinoma of the right lower bronchus with a swelling of the mediastinal and left supraclavicular lymph nodes in July of 1973. He received 60 Gy of irradiation in the right lung, the mediastinum, and the left supraclavicular region. Later, after doing well until August of 1986, a squamous cell carcinoma of the esophagus was found at the upper intrathoracic site. Thus, he also received additional radiotherapy but died of pneumonia after this local recurrence 7 months later. At autopsy, no local recurrence of the primary lung cancer was found. The site of esophageal cancer was far from that of the primary lung cancer though it was included in the previous treatment ports. This suggests the possibility that the primary esophageal cancer had been induced by therapeutic irradiation. So far as we know, this is the first report of esophageal cancer that may have developed after irradiation for lung cancer.

Aged↗