The preparation of the chronic hyper-endotoxemia experimental animal model by means of a drug delivery system.

A drug delivery system (DDS) consisting of lipopolysaccharide (LPS) as a drug and 2-hydroxyethyl methacrylate (HEMA)-diethylene glycol dimethacrylate (2G) or -polyethylene glycol dimethacrylate (4G, 9G) copolymer was prepared, and used for the efficient preparation of an experimental animal model of chronic hyper-endotoxemia. The release profiles of LPS in the in-vitro test were greatly influenced by the composition of HEMA-2G, 4G, 9G in the copolymer. It was found that LPS release from the DDS continued gradually and constantly throughout 2 weeks. In the in-vivo experiment with rats, the DDS maintained a high blood concentration level of LPS for 3 days. These results strongly suggest the possibility of convenient and reproducible preparation of a chronic hyper-endotoxemia animal model.

[Prolonged antinociceptive effect of poly (DL-lactic acid)-fentanyl composites after their intrathecal injection in rats].

We synthesized poly (DL-lactic acid)-fentanyl composites and compared the duration of analgesia after the administration of a single intrathecal dose of these agents in rats. The drug was injected with an intrathecal catheter into the intrathecal space. Fentanyl composites or plain fentanyl in doses of 2.5 or 25 micrograms were administered, respectively. Animals were then tested for analgesia using the tail-flick test. The release rate of fentanyl from fentanyl composites in vitro was also evaluated. The antinociceptive effect of fentanyl composites (25 micrograms) was significantly longer than that of plain fentanyl. Administration of poly (DL-lactic acid) alone did not induce the antinociceptive effect. Four of 7 animals given plain fentanyl (25 micrograms) exhibited temporary respiratory depression, but none of the animals given fentanyl composites showed this response. In vitro experiments demonstrated a slow release of fentanyl from the fentanyl composites. We conclude that the antinociceptive effect of fentanyl can be prolonged when administered as a poly (DL-lactic acid)-fentanyl composite in the intrathecal space with decreased systemic side effects compared with the plain formulation.

Ipsilateral dominance of human olfactory activated centers estimated from event-related magnetic fields measured by 122-channel whole-head neuromagnetometer using odorant stimuli synchronized with respirations.

The aim of this study was to measure and analyze olfactory event-related magnetic fields using a whole-cortex biomagnetometer (122-channel SQUID gradiometer). Amyl-acetate gas (approx. 1%) was administered for 300 msec into either the right or left nostril in synchronization with respiration using a mask and an optical fiber sensor. Clear olfactory event-related magnetic fields were asymmetrically obtained on both sides of the forehead in all six subjects. The generators of olfactory magnetic fields were estimated at two regions located fairly asymmetrivally near the bilateral frontal deep areas. The goodness-of-fit was better for the two-dipole model than the one-dipole model in all experiments. In almost all subjects the latency and intensity of ipsilateral olfactory magnetoencephalography (MEG) responses were shorter and larger than those of the contralateral responses, respectively. These results suggest that the olfactory MEG responses on the ipsilateral side are generally larger and more dominant than those on the contralateral side in the human olfactory system.

[Prolonged antinociceptive effect after epidural injection of polyethylene glycol-morphine composites in rats].

Epidurally administered morphine is useful in the management of postoperative or cancer pain, and a reliable method which can produce prolongation of analgesia with a single dose may be very useful. We synthesized a polyethylene glycol-morphine (PEG-morphine) composites and examined the duration of analgesia after a single epidural administration dose of this agent in the rat. The molecular weight of PEG was functionally evaluated. PEG-morphine was injected surgically along the epidural space. Morphine in doses of 2.5, 5.0 and 7.5 mg and PEG only were administered. A second group of animals received intramuscular injections of PEG-morphine (5.0mg). Animals were then tested for analgesia using the tail-flick test. The antinociceptive effect of 7.5mg was significantly longer than that of 2.5mg or 5.0mg. Neither PEG alone nor intramuscular administration of PEG-morphine induced antinociceptive effect. Sensory blockade was reversible and the animal appeared to have normal sensory perception. We conclude that the antinociceptive effect of morphine is dose-dependent and its duration can be prolonged when administered as a PEG-morphine composite in the epidural space.

Interstitial chemotherapy with biodegradable ACNU pellet for glioblastoma.

For patients with nonresectable glioblastoma (GB) or recurrent GB, we have recently been using an interstitial chemotherapy with biodegradable polylactic acid pellets containing nimustine chloride (ACNU), in combination with superselective arterial ACNU injection, routine irradiation and chemotherapy. The ACNU pellets are prepared by mixing polylactic acid powder and ACNU, and then melting the mixture at low temperature and moulding it into a thin pellet. Pharmacological anticancer activity was experimentally demonstrated by the finding that a region of suppression was present surrounding an ACNU pellet placed in a B6 melanoma cell culture disc, but that no such suppression was present around a control pellet. In order to determine the spatial and temporal distribution of ACNU, a small pellet (ACNU: 0.6 mg) was implanted in the frontal lobe of rats. ACNU concentration determined by HPLC was 61.0 micrograms/g brain tissue on day 1. 22.5 on day 3, and 5.5 on day 7; small amounts of ACNU were in fact released for at least 4 weeks after implantation. This pellet was used for the clinical treatment of 11 GB patients. Four patients had several pieces of pellets implanted immediately after CT-guided stereotactic biopsy, and the other 7 had pellets placed in residual tumor after partial removal at craniotomy. No ACNU was detectable in serum. CT studies obtained at subsequent appropriate intervals disclosed gas formation around the pellets, a slight increase in edema, and necrosis or decrease in CT enhancement of tumor beginning around day 12 after implantation. Bone marrow suppression did not occur, since ACNU was administered interstitially and in the range of 50-200 mg (average: 126 mg) per patient.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Continuous cellulase production by immobilized Sporotrichum cellulophilum and continuous saccharification of bagasse.

Immobilized Sporotrichum cellulophilum with nonwoven materials was cultured continuously by a rotating-disk fermentor to supply cellulase into the saccharification system. The filter paper activity (5.0) was retained after 696 h under conditions of 250 rpm stirring and 0.014 h(-1) dilution rate. The product of the culture was supplied continuously to the saccharification reactor and used for the saccharification of bagasse. A glucose solution of ca. 0.9% was obtained continuously from 5% bagasse slurry during 610 h saccharification by this method.

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.

Nature of yeast cells immobilized by radiation polymerization. Activity dependence on the water content of polymer carriers.

Higher activity of ethanol production due to higher density of yeast cells was observed in yeast cells immobilized with artificial polymer carriers of higher water content based on methoxypolyethyleneglycol methacrylate and 2-hydroxyethylacrylate. These polymer carriers were prepared by radiation-induced polymerization below 0 degrees C. Yeast cells were immobilized with these carriers by adsorption method during multiplication. Two possible reasons for higher activity were discussed.

[Treatment of malignant brain tumors with slowly releasing anticancer drug-polymer composites].

The purpose of this study is to present the methodology and results of a clinical trial of local chemotherapy of malignant brain tumors based on slowly-releasing anticancer drug-polymer composites. The slowly releasing drugs were prepared by combining and mutually dispersing anticancer agents with glassified monomers containing 10% polymetacrylic methyl acid and then this compound was frozen at -78 degrees C and exposed to 1 X 10(6) rad of gamma rays from cobalt 60. Thus we prepared a compound of polymers and anticancer agents. We used needle-shaped capsules of this compound. These capsules release the drug very slowly over 40 days. We administered locally to the malignant brain tumors with either slowly releasing mitomycin, slowly releasing adriamycin, slowly releasing ACNU or slowly releasing 5 Fu drugs. The following techniques were employed in implantation these capsules. Implantation into the remaining tumor wall at the time of excision. Implantation into the tumor by CT-guided stereotactic method. We implanted these drugs into tumor of 55 cases, thereafter we conducted both radiation and chemotherapy with ACNU in most patients. This method has the following advantages: It is possible to be employed to different types of anticancer agents. Both dosage and releasing time can be adjusted. It is possible to administer these capsules postoperatively by the stereotactic method. The clinical study consists of 55 patients, 20 cases of anaplastic astrocytoma, 23 cases of glioblastoma multiforme, 5 cases of oligodendroglioma, 3 cases of medulloblastoma and 4 cases of others. Survival rate estimated by Kaplan-Meier method was 47% in glioblastoma at 12 months and 91% in anaplastic astrocytoma at 18 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Periodical batch culture of the immobilized growing fungi Sporotrichum cellulophilum producing cellulase in the nonwoven materials.

The thermophilic fungus Sporotrichum cellulophilum was immobilized with nonwoven materials for cellulase production. The cellulose powder concentration in the medium was an important factor controlling cellulase production. When the cellulose powder concentration in the nonwoven materials was more than 4%, cellulase production was suppressed. The growth of the immobilized fungi depended on the spaces in the nonwoven materials. Immobilized growing fungi were retained by the non-woven materials, and the supernatant medium did not contain mycelia. The heat stability of the immobilized growing fungus was higher than that of the free fungus. The immobilized fungus gave the same FPA as the free mycelium, but the lag time for cellulase production in the immobilized fungus was longer. It was necessary for the only medium to be changed in order to get the immobilized growing fungus to continue producing cellulase. In this instance there was no difference of lag time in comparison with the free cells, and the supply of cellulose powder and polypepton was reduced to two-thirds. After 23 exchanges of the medium (2.6 mg cellulose powder/1 cm(3) nonwoven materials) FPA value was maintained. The periodic batch culture was continued for 69 days.

Effect of drug-vinyl copolymer delivery composites on the rat prostate.

A radiation polymerized drug-vinyl copolymer delivery composite (0.8 mm in diameter, 3 mm long) was inserted into the right-lobe ventral prostate (I), into the right testis (II), and subcutaneously (III) into the back of male Wistar rats. The implantation was carried out over a period of 12 weeks maximum. From the relationship between the site of surgical insertion of the implant and the physiologic response (as measured by the decrease in the weight of the prostatic organs, e.g., ventral prostates, dorsolateral prostates, and seminal vesicles), it was found that in an AA560-containing composite (36 micrograms daily), the physiologic response is increased in order of (III) greater than (II) greater than (I). The same tendency was observed in the Estracyt-containing composite system (15 micrograms daily). The difference in the physiologic response owing to the site of surgical insertion of the implant was not observed in an E2-17 beta-containing composite (6 micrograms daily), although this composite showed the strongest physiologic response. No physiologic response in rats with CMA-containing composite (28 micrograms daily) was noted.

Sheets obtained by radiation polymerization for enzyme immunoassay.

Immobilized anti-alpha-fetoprotein sheets, which were attached to sticks, for enzyme immunoassay of alpha-fetoprotein were prepared by radiation polymerization of hydrophilic monomers. The relationship between the preparation conditions and the activity of the sheets was studied. The activity varied with monomer concentration, hydrophilicity of polymer matrix, the amount of coating solution, and antibody concentration. The sheets obtained at relatively low monomer and antibody concentrations appeared to give a high activity. It was found that the sheets are applicable for the enzyme immunoassay of alpha-fetoprotein with high sensitivity.

Preparation by irradiation of a solid support for enzyme immunoassay.

Reagents (immobilized anti-alpha-fetoprotein discs) having a porous structure were prepared for enzyme immunoassay of alpha-fetoprotein by radiation polymerization at low temperatures. Discs were attached to sticks for easy handling. The activity (determined by absorbance at 492 nm) of the discs varied with the hydrophilic properties and size of the disc. The discs are sufficiently sensitive and precise for enzyme immunoassay of alpha-fetoprotein.

Immobilization of enzymes masks their active site.

We studied the effect of immobilizing cellulase to carboxycellulose sodium by radiation polymerization on the masking of the active site of the enzyme. Masking of the enzyme during the preparation of immobilized enzyme was assayed at low temperature. The activity of immobilized enzyme was retained during repeated batch reactions, indicating that the enzyme was firmly trapped in the polymer matrix. Various compounds (designated monomers) were used to dissolve the carboxymethylcellulose; enzyme activity was affected by the nature of the monomer, by the monomer concentration, and by the solubility of the substrate in monomer.