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Biomedical subjects

T Mashimo

Publications and source records attributed to T Mashimo.

At least 55 records · Page 3Linked to original sources
PubMed1990

Sequential polydepsipeptides as biodegradable carriers for drug delivery systems.

Sequential polydepsipeptides containing both peptide and ester bonds, poly[(L-alanyl)n-gamma-ethyl L-glutamyl-L-lactyl] (n = 0, 1, 2, and 3) (poly[(Ala)n-Glu(OEt)-Lac]), were prepared for application as biodegradable carriers for drug delivery systems. The in vivo degradation of these polymers was evaluated by subcutaneous implantation in the backs of male rats, and was strongly influenced by the number (n) of Ala units in poly[(Ala)n-Glu(OEt)-Lac]. The resulting poly(Ala-Ala-Glu(OEt)-Lac) gave the highest degradability, in which 100% degradation was observed 24 weeks from the start of implantation. A luteinizing-hormone-releasing hormone agonist des-Gly10-[D-Leu6]-LH-RH ethylamide (LH-RH agonist), was incorporated into a sequential poly(Ala-Ala-Glu(OEt)-Lac) carrier by the melt-pressing technique, which gave fine cylindrical polymer formulations with different structures of drug dispersion, e.g., blend-type and sandwich-type formulations. The rate of in vivo release of LH-RH agonist from a blend-type formulation showed a linear decrease with time until its release was finished after 6 weeks' implantation. In contrast, in a sandwich-type formulation, the in vivo release rate was apparently maintained constant over a period of 16 weeks (24 +/- 14 micrograms/day).

Amino Acid Sequence↗
PubMed1990

In vivo characteristics of low molecular weight copolymers composed of L-lactic acid and various DL-hydroxy acids as biodegradable carriers for drug delivery systems.

Low molecular weight and amorphous copolyesters composed of 70 mol% L-lactic acid and 30 mol% DL-hydroxy acids such as DL-lactic acid, DL-alpha-hydroxy-n-butyric acid, DL-alpha-hydroxyisovaleric acid and DL-alpha-hydroxyisocaproic acid were synthesized by direct copolycondensation in the absence of catalysts, to evaluate their in vivo capabilities as biodegradable carriers for drug delivery systems. For this purpose, the copolyester was moulded into a small cylindrical specimen under melt-pressing technique and implanted subcutaneously in the back of male adult rats. The in vivo degradation pattern can be subdivided into three types: the formations of parabolic type (L-LA/DL-HBA copolymer), linear type (L-LA/DL-LA copolymer) and S type (L-LA/DL-HIVA and L-LA/DL-HICA copolymers). A luteinizing hormone-releasing hormone agonist, des-Gly10-(D-Leu6)-LH-RH ethylamide monoacetate (LH-RH agonist), was incorporated into the small cylinders of copolyester formulations, of which the strongest pharmacological influence was observed in a copoly(L-LA/DL-HICA) formulation system, resulting in the maintenance of effective pharmacological influence throughout an experimental period of 15 wk, at which the in vivo release rate of LH-RH agonist was held constant at approximately 45 micrograms/d.

Animals↗
PubMed1990

Purification of 45 KDa estramustine binding protein (EMBP) and preparation of its antibody.

The purification of 45 KDa EMBP and the production of monospecific anti-serum is described. 45 KDa EMBP was purified by relatively simple methods using ion exchange HPLC (TSK-GEL DEAE-5PW column) and size exclusion HPLC (TSK-GEL G3000SW column). The results clearly demonstrated the speed and simplicity of the method using these columns, compared to previously-described methods for purification of 45 KDa EMBP.

Amino Acids↗
PubMed1989

[Combination therapy of renal cell carcinoma with interferon-alpha and UFT (or FT-207)].

Human lymphoblastoid interferon (IFN-alpha MOR-22; OIF) was administered to forty-two patients suffering from renal cell carcinoma. Twenty-six patients with metastatic lesions or primary tumor were treated in a clinical trial with either MOR-22 alone or combination of MOR-22 and UFT (or FT-207). The efficacy was assessed in ten of twenty patients who had received MOR-22 alone for more than eight weeks, but objective response was not observed. The efficacy was done in eight of fourteen patients with MOR-22 and UFT (or FT-207) in combination. Complete response was achieved in one, and partial response in two, with an objective response rate of 37.5%. But the difference was no statistically significant in the survival rate of each therapy. In evaluable twenty patients with MOR-22 prophylactically, there was only one case who had occurred lung metastases with a refractory rate of 8.3%. Forty-one patients were examined for side effects to drugs. The main side effects were fever, anorexia, general fatigue, hematologic toxicities, and hepatic dysfunction in both therapy. These side effects occurred with more increased frequency in combination therapy of UFT (or FT-207) compared to MOR-22 alone.

Adult↗
PubMed1989

In vivo release of cisplatin from a needle-type copolymer formulation implanted in rat kidney.

Cisplatin, cis-dichlorodiamine platinum (II), was incorporated in a needle-type copolymer formulation (0.8 mm diameter, 6 mm long) by radiation-induced polymerization. The copolymer used was copoly(diethylene glycol dimethacrylate/polyethylene glycol #600 dimethacrylate, 80/20 vol%). This copolymer, containing 6 mg of cisplatin, was implanted into the kidney of adult male Wistar rats (420 +/- 20 g). A total of 70 d was required for 100% release of cisplatin in vivo. The kidney tissue surrounding the formulation was strongly necrotized by the action of cisplatin. Two layers of necrosis could be distinguished: necrotic tissue surrounding the formulation and necrobiotic tissue surrounding the necrotic tissue. The amount of necrotic tissue changed markedly over time, but no change was apparent in the amount of necrobiotic tissue. The maximal amounts of necrotized tissue were observed 14 d after implantation: 3100 microns and 600 microns thick for the necrotic and necrobiotic tissues, respectively.

Animals↗
PubMed1989

In vivo characteristics of low molecular weight copoly (D,L-lactic acid) formulations with controlled release of LH-RH agonist.

Amorphous and crystalline copolymers with a relatively low molecular weight of 1800 were synthesized by direct copolycondensation of D-lactic acid and L-lactic acid in the absence of a catalyst, to evaluate their in vivo capabilities as biodegradable carriers for drug delivery systems. A luteinizing hormone-releasing hormone agonist, des-Gly10-(D-Leu6)-LH-RH ethylamide, was incorporated in a fine cylindrical copolymer formulation, under melt-pressing technique, a mild heat-pressure condition. This formulation was implanted subcutaneously in the back of male rats. The rate of in vivo degradation of amorphous copolymer was much faster than that of crystalline copolymer. Contrary to this tendency, the in vivo release of the drug from this amorphous formulation was held constant over a longer period, compared with the crystalline formulation. This can be closely related to the difference in dispersion of the drug in the formulation.

Animals↗
PubMed1988

[An adenoid tumor of the epididymis--electron microscopy and immunohistochemistry].

A case of an adenomatoid tumor of the epididymis is reported. The patient, a 41-year-old male, had a total right orchiectomy of his testicular mass. The tumor was located in the inferior portion of the right epididymis and was a well-circumscribed solitary mass, measuring 3 X 3 X 3 cm. Microscopically, the tumor contained plump acidophilic cells arrange in cords and trabecula with fibrous connective tissue. Immunohistochemical studies for keratin and vimentin in the tumor cells were positive. Electron microscopical findings of the tumor were similar to those of a benign mesothelioma. These findings suggest that adenomatoid tumors are of mesothelial origin.

Adult↗
PubMed1987

Studies of the slow releasing of testosterone from radiation-polymerized testicular prostheses implanted subcutaneously in the back of castrated rabbits.

A controlled release testicular prosthesis containing testosterone, which was previously dissolved in 2-hydroxyethyl methacrylate (HEMA) at a temperature of 80 degrees C, was prepared by radiation-induced polymerization in the supercooled state at a low temperature. The daily dose of testosterone released in vitro from the poly(HEMA) testicular prosthesis was kept constant at a rate of 5.5 +/- 1.5 mg/d throughout an experimental period of 900 d. In the in vivo experiments, the poly(HEMA) testicular prosthesis was implanted subcutaneously in the back of castrated rabbits over a maximum period of 11 mnth. The cumulative amounts of testosterone released in vitro and in vivo from the poly(HEMA) testicular prosthesis for a period of 11 mnth were found to be 2.1 g (30.0 wt% of initial drug) and 0.9 g (12.8 wt% of initial drug), respectively. The serum testosterone level in castrated rabbits with a poly(HEMA) testicular prosthesis rapidly decreased for periods up to 2 mnth (after increasing during the first 2 wk), then showed a moderate decrease for a few months, and finally held constant at a level of 10 ng/ml throughout the experimental period. It was concluded that a slight amount of testosterone is continuously released in vivo from the radiation-polymerized poly(HEMA) testicular prosthesis over a long period analogous with that in vitro.

Animals↗
PubMed1986

Electroretinogram as a possible monitor of anesthetic depth.

The effects of volatile anesthetics, i.e., methoxyflurane, halothane and enflurane, on the electroretinogram (ERG) were studied in 15 albino rabbits. The ERG was analyzed in terms of the a-wave, and the first oscillatory component (01) in the b-wave. The 01 peak latency showed a significant dose-related prolongation when anesthetic end-tidal concentrations were in excess of 0.8 minimum alveolar concentration (MAC). One MAC, a measure of anesthetic potency, is the end-tidal concentration of an anesthetic at 1 atmosphere that induces immobility in 50% of animals against a noxious stimulus. The amplitudes of the a-wave and the 01 decreased in dose-dependent manners, but their changes were less striking than those of the 01 latency. The peak latency of the a-wave remained unchanged. We conclude that the 01 peak latency is a useful monitor of the depth of inhalational anesthesia.

Anesthesia↗
PubMed1986

Dual effect of local anesthetics on the function of excitable rod outer segment disk membrane.

The effects of local anesthetics and a divalent cation, Ca2+, on the function of rhodopsin were estimated from the measurements of light-induced proton uptake. The light-induced proton uptake by rhodopsin in the rod outer segment disk membrane was enhanced at lower pH (4) but depressed at higher pHs (6 to 8) by the tertiary amine local anesthetics lidocaine, bupivacaine, tetracaine, and dibucaine. The order of local anesthetic-induced depression of the proton uptake followed that of their clinical anesthetic potencies. The depression of the proton uptake versus the concentration of the uncharged form of local anesthetic nearly describes the same curve for small and large dose of added anesthetic. Furthermore, a neutral local anesthetic, benzocaine, depressed the proton uptake at all pHs between 4 and 7. These results indicate that the depression of the proton uptake is due to the effect of only the uncharged form. It is hypothesized that the uncharged form of local anesthetics interacts hydrophobically with the rhodopsin in the disk membrane. The dual effect of local anesthetics on the proton uptake, on the other hand, suggests that the activation of the function of rhodopsin may be caused by the charged form. There was no significant change in the light-induced proton uptake by rhodopsin when 1 mM of Ca2+ was introduced into the disk membrane at varying pHs in the absence or presence of local anesthetics. This fact indicates that Ca2+ ion does not influence the diprotonating process of metarhodopsin; neither does it interfere with the local anesthetic-induced changes in the rhodopsin molecule.

Anesthetics, Local↗
PubMed1986

[Clinical evaluation of norfloxacin in gonococcal urethritis].

Norfloxacin, a new quinolinecarboxylic acid derivative, was administered to 30 male patients with gonococcal urethritis at a daily dose of 600 mg for 7-21 days. The clinical response was evaluated after administration of 7 days as excellent; Negative culture of N. gonorrhoeae. WBC less than 3/hpf in first voided urine sediment, good; Negative culture, WBC greater than or equal to 3/hpf, and poor; Positive culture. The result was excellent in 14 cases and good in 16 cases. No subjective side effects were observed. The minimum inhibitory concentration (MIC) distribution against the clinically isolated 30 strains of N. gonorrhoeae ranged from 0.0096 micrograms/ml to 0.34 micrograms/ml. Seven of thirty strains were resistant to ABPC. The MIC of these 7 strains ranged from 0.018 micrograms/ml to 0.18 micrograms/ml. Seven cases with ABPC resistant strains had a similar clinical response to other cases. Twelve patients (40%) developed post gonococcal urethritis for 7-14 days after treatment. Clinical observation of this series suggests that a 7 day therapy of Norfloxacin for the patients with gonococcal urethritis is sufficiently effective and that treatment should be changed to other antibacterial agents in the case of post gonococcal urethritis, since continuous administration for more than 7 days of Norfloxacin is not so effective.

Adult↗