Effects of Hsp90 inhibitor on the RIP1-RIP3-MLKL pathway during the development of heart failure in mice

Necroptosis is a programmed form of necrotic cell death. Necroptosis is regulated by the necroptosis-regulating proteins including receptor-interacting protein (RIP) 1, RIP3, and mixed lineage kinase domain-like (MLKL), the activities of which are modulated by the molecular chaperone heat-shock protein (Hsp) 90. Presently, to clarify the relationship between Hsp90 and necroptotic pathway proteins, RIP1, RIP3, and MLKL in the development of heart failure, we examined the effects of Hsp90 inhibitor treatment on the RIP1-RIP3-MLKL pathway in mice following transverse aortic constriction (TAC). In this study, TAC mice showed typical signs of heart failure at the 8th week after the operation. In the failing heart, the levels of these regulatory proteins and those of their phosphorylated forms were increased, suggesting that necroptosis contributed to the development of heart failure in the TAC mice. The increases in RIP1, RIP3, and MLKL after TAC were reversed by the administration of an Hsp90 inhibitor. Furthermore, the rise in the phosphorylation levels of these 3 proteins were attenuated by the Hsp90 inhibitor. Concomitantly, cardiac functions were preserved. We also found that exposure of cultured adult mouse cardiomyocytes to the Hsp90 inhibitor attenuated necrotic cell death induced by tumor necrosis factor-α via suppression of RIP1, RIP3, and MLKL activation in in vitro experiments. Taken together, our findings suggest that inhibition of Hsp90 should have therapeutic effects by reducing the activation of RIP1-RIP3-MLKL pathway in the hypertrophied heart and thus could be a new therapeutic strategy for chronic heart failure.

Recalcitrant facial pemphigus vulgaris: correlation of skin lesions with the ratio of antidesmoglein antibodies 1 and 3

Pemphigus vulgaris (PV) is an autoimmune bullous disease characterized by autoantibodies against desmogleins. We report a case of recalcitrant PV, which progressed from the mucosal to the mucocutaneous type, with a corresponding increase in anti-desmoglein (Dsg)1 and decrease in anti-Dsg3 antibody titres. Thus, the clinical features seemed to correlate with the ratio of anti-Dsg1 and 3. The patient also had anti-Dsg4 antibodies, which might be related to the nonscarring diffuse hair loss and marked facial involvement she also had. The patient did not respond to treatment with systemic steroid, ciclosporin, azathioprine, cyclophosphamide or double filtration plasmapheresis, and eventually died from fulminant thrombotic thrombocytopenic purpura of unknown cause.

In vivo fluence rate and fractionation effects on tumor response and photobleaching: photodynamic therapy with two photosensitizers in an orthotopic rat tumor model

The effect of fluence rate and light fractionation on phototoxicity was investigated in vivo in an orthotopic rat bladder tumor model. Two photosensitizers, benzoporphyrin derivative monoacid ring A and 5-aminolevulinic acid-induced protoporphyrin IX, were studied. For a given cumulative light dose of 30 J/cm2, enhanced tumor destruction was observed from both photosensitizers when using either lower fluence rates or fractionated light delivery. Photobleaching experiments in vivo demonstrated that the photobleaching rate, however, was not fluence rate dependent. The fluence rate and light fractionation effects on tumor phototoxicity lead to rapid local depletion in oxygen concentration that inhibited subsequent photochemical reactions necessary for efficient photodestruction of tumor cells. Nicotinamide did not enhance photodynamic therapy efficacy, suggesting that the added increase of oxygen within the tumor was not sufficient to enhance photodestruction of hypoxic cell fractions. The independence of the photobleaching rate with fluence rate suggests distinct mechanisms, at least in part, of photodestruction of the tumor and the photosensitizer and that the rate of photosensitizer photo-bleaching may not always be an appropriate monitor for singlet oxygen availability and photodynamic therapy dosimetry.

In vitro studies indicating antioxidative properties of rebamipide

Rebamipide is the first anti-gastric ulcer and antigastritis drug that not only increases endogenous prostaglandin in gastric mucosa but also scavenges oxygen-derived free radicals and inhibits their production. In the present paper, we have reviewed the antioxidative and antiinflammatory properties of rebamipide mainly demonstrated by in vitro studies. The study, using the electron paramagnetic resonance (EPR) spin trapping technique, showed that superoxide production was inhibited by rebamipide when isolated human neutrophils were stimulated with opsonized zymosan or Helicobacter pylori water extract in a dose-dependent manner. Chemiluminescence generated from neutrophils activated by H. pylori or formyl-methionyl-leucyl-phenylalanine was also decreased by the treatment with rebamipide. Rebamipide, at concentrations of 10(-5) and 10(-6) M, reduced the adherence of neutrophils to endothelial cells as well as the CD18 expression on neutrophils induced by H. pylori water extract. The EPR study also demonstrated the direct hydroxyl radical scavenging activity of rebamipide, and a kinetic study showed that the second-order rate constant for the reaction between rebamipide and hydroxyl radical was 2.24 x 10(10) M(-1)/s(-1). The inhibitory effect of rebamipide on lipid peroxidation induced by a free radical initiator was also demonstrated by the in vitro system using rat gastric mucosal homogenates. These data indicate that rebamipide offers a potential for protection against reactive oxygen- and activated neutrophil-associated gastric mucosal injury by scavenging hydroxyl radical and inhibiting neutrophil activation or lipid peroxidation.

Rebamipide protects against indomethacin-induced gastric mucosal injury in healthy volunteers in a double-blind, placebo-controlled study

The aim of the present study was to evaluate rebamipide in the prevention of indomethacin-induced gastric mucosal injury in healthy volunteers. Twenty healthy males (mean age 21.8 years, range 20-26) participated. This is a randomized, double-blind, placebo-controlled study. The 20 subjects were randomized to either indomethacin 25 mg three times a day and placebo three times a day or indomethacin and rebamipide 100 mg three times a day for seven days. Endoscopy was performed at baseline and again after the treatment. In the placebo group, eight of 10 subjects (80%) developed symptoms compared to three of seven (43%) in the rebamipide group. The incidence of gastric lesions was 70% in the placebo group, which was significantly higher than that in the rebamipide group (14%). The lipid peroxide levels in the mucosa of the gastric body significantly increased in the placebo group. This increase was not inhibited by rebamipide. Myeloperoxidase activity in the gastric mucosa tended to increase in the placebo group, but tended to decrease in the rebamipide group. These results indicate that rebamipide may be an effective prophylaxis against indomethacin-induced gastropathy in humans.

Role of active oxygen species and lipid peroxidation in mepirizole-induced duodenal ulcers in rats

The role of active oxygen species and lipid peroxidation in the pathogenesis of duodenal ulcers induced by mepirizole was investigated in rats. Oral administration of mepirizole (200 mg/kg) resulted in ulcer lesions in the proximal duodenum. Thiobarbituric acid-reactive substances (TBA-reactive substances), an indicator of lipid peroxidation, also significantly increased in the duodenal mucosa. Myeloperoxidase (MPO) activity in the duodenal mucosa, a sign of polymorphonuclear leukocyte (PMN) accumulation, significantly increased. Combination treatment with polyethylene glycol-modified Serratia Mn-SOD and catalase significantly decreased the size of the ulcers and TBA-reactive substances in the duodenal mucosa. Allopurinol, a xanthine oxidase inhibitor, also reduced the size of duodenal ulcers. Both the size of the ulcers and the increase in TBA-reactive substances in the duodenal mucosa were significantly lower in PMN-depleted rats. Mepirizole increased the surface expression of adhesion molecule CD18 on PMNs in vitro. These results suggest that lipid peroxidation, mediated by active oxygen species generated from xanthine oxidase and PMNs, plays an important role in the pathogenesis of duodenal ulcers induced by mepirizole.

Efficacy of hyperthermia and polyunsaturated fatty acids on experimental carcinoma

We investigated the efficacy of hyperthermia and gamma-linolenic acid on experimental carcinoma. This study focused on polyunsaturated fatty acids that are substrates for free radical reactions. Oleic acid, linolenic acid, alpha-linolenic acid, or gamma-linolenic acid was injected into the arteries feeding AH109A carcinoma implanted into rat hind limbs. Among these, gamma-linolenic acid had the greatest effect on tumor tissue lipid peroxidation and demonstrated an antitumor effect. Consequently, gamma-linolenic acid injection into the feeding artery of a tumor was performed immediately prior to hyperthermia. This combination therapy induced a high level of lipid peroxidation in tumor tissue and a significant antitumor effect. Hyperthermia combined with gamma-linolenic acid produces free radical reactions by increasing the radical reaction substrate and may be an effective anticancer modality.

Anti-tumor effects of hyperthermia plus granulocyte colony-stimulating factor

The role of neutrophils in the anti-tumor effects of hyperthermia was investigated in an experimental rat model, and the efficacy of hyperthermia combined with recombinant human granulocyte colony-stimulating factor (G-CSF) was similarly investigated. AH109A carcinoma cells were transplanted into the hind legs of Donryu rats, then heated by a radio-frequency dielectric heater. In this study, because the myeloperoxidase (MPO) activity of neutrophils was not affected by heating or G-CSF, MPO activity was measured as an index of neutrophil migration into tumor tissue. After hyperthermia, MPO activity in tumor tissue increased significantly, suggesting migration of neutrophils into tumor tissue. Depletion of circulating neutrophils by the intraperitoneal injection of anti-rat neutrophil antibody decreased the anti-tumor effects of hyperthermia. Subsequently, we used hyperthermia plus intraarterial G-CSF to enhance the anti-tumor effect. Hyperthermia was induced 1 h after injection of G-CSF, a time when MPO activity in tumor tissue was maximal. A satisfactory thermal effect was noted even in cases where tissue could not be heated sufficiently. In conclusion, neutrophils have an important role in the anti-tumor effects of hyperthermia, and administration of G-CSF enhances these effects.

Local gastric and serum concentrations of rebamipide following oral administration to patients with chronic gastritis

The potential anti-ulcer action of rebamipide (CAS 11911-87-6, OPC-12759) on experimental and clinical injury to the gastric mucosa depends on its presence in sufficient concentration in the gastric mucosa. To investigate its local penetration, rebamipide levels in the gastric mucosa and serum were measured. A dose of 100 mg of rebamipide was given orally (tablet) to patients with chronic gastritis (n = 32). Gastroscopy was performed between 22 and 353 min after drug ingestion. Venous blood was sampled for determination of serum concentrations. Samples were analyzed by high-performance liquid chromatography (HPLC). The maximal concentration in the gastric mucosa was reached after 30-60 min, and the concentration remained elevated for about 120 min thereafter. The mean mucosal concentration of rebamipide between 30 and 120 min after ingestion was 60.0 +/- 109.8 micrograms/g of tissue, which was higher than 0.1 mmol/l (37 micrograms/g of tissue). The serum concentration of rebamipide peaked about 30-60 min after drug ingestion and remained elevated for about 5 h thereafter. The mean serum concentration of rebamipide between 30 and 120 min after ingestion was 0.25 +/- 0.23 microgram/ml, being below the level of 1.0 mumol/l (0.37 microgram/ml). Data indicate that the concentration of rebamipide in the gastric mucosa resulted from local penetration, and suggest that the blood level and systemic distribution of rebamipide have little effect on its antioxidative and anti-neutrophilic activities.

Rebamipide protects against activation of neutrophils by Helicobacter pylori

Our objectives were to determine whether rebamipide, a unique antiulcer agent, would inhibit adhesive reactions between neutrophils and endothelial cells as well as the production of active oxygen species from neutrophils elicited by an extract of H. pylori. A water extract of H. pylori that was prepared from biopsy materials obtained from a patient with gastric ulcer increased the surface expression of CD18 on human neutrophils isolated from peripheral blood, the adhesion of neutrophil-endothelial cells, and the production of active oxygen species by neutrophils. Rebamipide, at concentrations of 10(-5) and 10(-6) M, reduced the adherence of neutrophils to endothelial cells as well as the CD18 expression on neutrophils induced by this bacterial extract. Rebamipide also inhibited the production of active oxygen species from neutrophils stimulated by H. pylori extract. These results suggest that rebamipide protects against the gastric mucosal inflammation associated with H. pylori by inhibiting neutrophil function.

Role of neutrophil-mediated inflammation in aspirin-induced gastric mucosal injury

The objectives of this study were to determine the roles of neutrophil-endothelial cell interactions and oxygen-derived free radicals in the pathogenesis of aspirin-induced gastric mucosal injury in rats. Oral administration of acidified aspirin (200 mg/kg) resulted in linear hemorrhagic erosions and an increase in myeloperoxidase activity, an index of neutrophil infiltration, in the gastric mucosa. Aspirin-induced gastric damage and the increase in myeloperoxidase activity were significantly inhibited by the injection of anti-CD11a, anti-CD11b, anti-intercellular adhesion molecule-1 monoclonal antibodies, and the combination of superoxide dismutase and catalase, which are scavengers of active oxygen species. These results suggest that neutrophil-endothelial adhesive interactions, which occur via CD11a/ CD18- and CD11b/CD18-dependent interactions with intercellular adhesion molecule-1, and oxygen-derived free radicals produced by neutrophils are implicated in the production of aspirin-induced gastric mucosal injury.

Biodistribution and phototoxicity of 5-aminolevulinic acid-induced PpIX in an orthotopic rat bladder tumor model

5-Aminolevulinic acid (ALA) is a precursor of heme biosynthesis. In the penultimate step of this biosynthesis, protoporphyrin IX (PpIX), an effective photosensitizer, is generated. In this study, the biodistribution and photodynamic effect of ALA-induced PpIX were investigated in an orthotopic rat bladder tumor model. A quantitative comparison of PpIX biodistribution by extraction and fluorescence spectroscopy following intravenous and intravesical administration of ALA was made. The tumor to normal bladder wall ratio was 2:1 at 4 hours for both delivery modes. Fluorescence microscopy demonstrated predominantly cellular rather than stromal PpIX fluorescence. Phototoxicity, evaluated 4 hours after ALA administration, was light dose-dependent with the most efficient tumor necrosis being observed upon 150 J/cm.2 of 630 nm. irradiation. These data suggest that optimized photodynamic therapy with ALA-induced PpIX may be an alternative treatment for superficial bladder carcinoma.

TAN-1323 C and D, new concanamycin-group antibiotics; detection of the angiostatic activity with a wide range of macrolide antibiotics

We detected potent angiostatic activity in a MeOH extract from the mycelia of microbial strain S-45628 in the chick chorioallantoic membrane (CAM) assay. The producer was taxonomically characterized as Streptomyces purpurascens. Active principles designated TAN-1323 A-D were isolated and determined to be 18-membered macrolide antibiotics; components C and D are new members of this group, while components A and B are identical to concanamycins C and A, respectively. When tested in the CAM assay, components B and D gave huge avascular zones at the extremely low doses of 10-100 ng/disk, although components A and C showed far weaker activity due to their preferential tissue-damaging effect on the CAM. The discovery that these 18-membered macrolide antibiotics are angiostatic substances prompted us to examine other types of macrolide antibiotics, leading to the discovery that 16-membered macrolide antibiotics such as bafilomycin C1, tylosin and leucomycin also show angiostatic activity on the CAM. Thus, angiostatic potential is widely distributed among macrolide antibiotics. The mechanism of action of these macrolide antibiotics is also discussed.

Insulin fragments as a carrier for peptide delivery across the blood-brain barrier

The possibility of using insulin (INS), which is transported into the brain by receptor-mediated transcytosis, as a peptide carrier for delivery across the blood-brain barrier (BBB) was investigated. After mice received an i.v. injection of horseradish peroxidase (HRP, M.W., 40,000) conjugated with INS, the HRP activity in the brain was higher than that after HRP injection. Since INS-HRP lowered the blood glucose level, we prepared insulin fragments by chemical and enzymatic procedures in an effort to find a carrier with no hypoglycemic activity. Seven fragments were synthesized taking the binding regions into consideration, but none showed any receptor binding affinity in cultures of bovine brain microvessel endothelial cells (BMEC). However, the fragment (F007) obtained by trypsin digestion showed high affinity and scarcely any hypoglycemic activity in mice even at a dose ten times the effective dose of insulin. These results suggest that this fragment may be useful as a carrier to transport therapeutic peptides across the BBB.

TAN-1496 A, C and E, diketopiperazine antibiotics with inhibitory activity against mammalian DNA topoisomerase I

Fungal metabolites with an epi-oligothiadiketopiperazine structure, TAN-1496 A, C and E, were isolated from the culture broth of Microsphaeropsis sp. FL-16144. Their molecular formulas were determined to be C22H28N2O9S2, C22H28N2O9S3 and C22H28N2O9S4, respectively. Structures were determined by comparing the NMR data with those of known diketopiperazine antibiotics, sirodesmins. These metabolites inhibited the relaxation of supercoiled pBR322 DNA by calf thymus topoisomerase I but did not affect the decatenation of kinetoplast DNA by calf thymus topoisomerase II at concentration up to 500 microM. They strongly suppressed the growth of various murine and human tumor cells and induced apoptosis. Moreover, various derivatives were synthesized to investigate the relationship of their functional groups and biological activities.

Antitumor effect of ischemia-reperfusion injury induced by transient embolization

The effect of ischemia-reperfusion, induced by the transient embolic agent degradable starch microspheres (DSMs) on tumor tissue was investigated from the standpoint of active oxygen species. Rabbits with VX2 carcinoma received regional infusion of DSMs by transcatheter angiography, and it was confirmed that DSMs occluded tumor vessels. Blood flow in the tumors decreased rapidly immediately after the DSM treatment and returned to the original level within 40 min. The size of tumors did not change after a single infusion of DMS, while five repeated DSM treatments led to a significant reduction in tumor size. This reduction in tumor size was prevented by the treatment of rabbits with superoxide dismutase and catalase, indicating that the generation of active oxygen species in the tumor was involved in the mechanism of action of DSMs. Thiobarbituric acid-reactive substances also increased in the tumors after DSM infusion, and this increase was also inhibited by treatment with superoxide dismutase and catalase. In conclusion, the antitumor effect of the transient embolic agent DSM is secondary to the phenomenon of ischemia-reperfusion injury. In addition, active oxygen species and lipid peroxidation are possible causes of ischemia-reperfusion injury.

A mechanistic study of cellular photodestruction with 5-aminolaevulinic acid-induced porphyrin

5-Aminolaevulinic acid (ALA)-induced porphyrin biosynthesis and phototoxicity in vitro was investigated in five malignant and two normal cell lines. Intracellular protoporphyrin IX (PpIX) content was quantified by extraction and fluorescence spectroscopy. Cellular PpIX content did not always correlate with cell proliferation rate as measured by the doubling times of cell lines. Cellular efflux of PpIX was also investigated. In a bladder carcinoma cell line, the observed rapid efflux was not blocked by verapamil, an inhibitor of the P-glycoprotein efflux pump. These data support the view that cellular PpIX accumulation is a dynamic process that is determined by both the efflux of PpIX from the cells and enzyme activities in the haem biosynthesis pathway. Desferrioxamine (desferal), a modulator of PpIX biosynthesis, enhanced ALA-induced cellular PpIX content significantly in all carcinoma cell lines but not in non-malignant cell lines. The enhanced PpIX cellular accumulation is attributed to inhibition of ferrochelatase activity, the enzyme responsible for the conversion of PpIX to haem. PpIX-mediated cellular photodestruction following irradiation with an argon ion laser at 514.5 nm was determined by the 'MTT assay'. There appeared to be a 'threshold' effect of cellular PpIX content; cells that synthesised less than 140 ng/mg-1 protein exhibited very little phototoxic damage, while cell lines having greater than 140 ng PpIX/mg-1 protein [corrected] exhibited a consistent phototoxic response. Among the cell lines which did undergo phototoxic damage, there was not a strict correlation between PpIX cellular content and ALA-induced phototoxicity. Desferal enhanced the PpIX content and phototoxic effect in the responsive cells. Fluorescence microscopy of the ALA-treated cells revealed marked accumulation of PpIX in mitochondria (rhodamine 123 co-staining). That the primary site of phototoxic damage is also the mitochondria was confirmed by electron micrographs of cells photosensitised with ALA-induced PpIX, which showed swelling of mitochondria within minutes after irradiation while other suborganelles appeared to be unaffected. The repair or further destruction of the mitochondria was fluence and cell-type dependent. The data from this study suggest that the basis of increased ALA-induced PpIX accumulation in tumours is a combination of various aspects of the metabolic process and pharmacokinetics and that the efficacy of photodestruction of malignancy will be determined not only by the rate of PpIX synthesis but also by specific cellular and tissue characteristics.

New naphthacenecarboxamide antibiotics, TAN-1518 A and B, have inhibitory activity against mammalian DNA topoisomerase I

New naphthacenecarboxamide antibiotics, TAN-1518 A and B, were isolated from a culture broth of Streptomyces sp. AL-16012. Their structures were elucidated from their reactions and from spectroscopic analyses. The relaxation of supercoiled pBR322 DNA by calf thymus DNA topoisomerase I was inhibited by these metabolites as potently as by camptothecin. However, the decatenation of kinetoplast DNA by calf thymus DNA topoisomerase II was little affected by these agents. The major metabolite, TAN-1518 A, strongly suppressed the growth of various murine and human tumor cells, inducing apoptosis. Unlike camptothecin, TAN-1518 A did not stimulate cleavable complex formation in the nuclei of CHO-K1 cells and had weak activity in intercalating into DNA strands. This metabolite arrested the growth of human tumor cell lines in G1 phase of the cell cycle. These results suggest that TAN-1518 A and B are novel antitumor agents targeting topoisomerase I.

Novel retrovirus protease inhibitors, RPI-856 A, B, C and D, produced by Streptomyces sp. AL-322

Four kinds of retrovirus protease inhibitors (RPI-856 A, B, C and D) were isolated as white powder from the culture filtrate of a soil isolate, Streptomyces sp. AL-322 by column chromatography using Diaion HP-20, Sephadex LH-20, ODS reversed phase HPLC and SP-2SW ion exchange HPLC. The structures of these inhibitors were elucidated by physico-chemical properties, chemical reactions and spectral analyses, as valyl-ADPAA-leucyl-AOPBA-valyl-valyl-aspartic acid (RPI-856 A and B) and valyl-ADPAA-leucyl-AOPBA-valyl-valine (RPI-856 C and D) [ADPAA = 2-amino-2-(3,5-dihydroxyphenyl)acetic acid, AOPBA = 3-amino-2-oxo-4-phenylbutyric acid]. RPI-856 A and B, and RPI-856 C and D were both determined to be diasteromers each other on the asymmetric carbon in AOPBA. These four inhibitors strongly inhibited in vitro HIV-1 protease and HTLV-I protease both derived from recombinant Escherichia coli with IC50 of 10(-7) approximately 10(-8) M.

Effect of rebamipide on lipid peroxidation and gastric mucosal injury induced by indometacin in rats

The protective effect of rebamipide (CAS 11911-87-6), a novel anti-ulcer agent, was investigated in rats with hemorrhagic erosions on the glandular stomach induced by intragastric administration of 25 mg/kg of indometacin. Pretreatment with 100 mg/kg of rebamipide significantly inhibited the increase in total area of erosions in the stomach and the increase in lipid peroxides in the gastric mucosa. Rebamipide also inhibited the in vitro increase of lipid peroxides in the gastric mucosal homogenates induced by free radical initiators. These results indicate that rebamipide's protective effect against indometacin-induced gastric mucosal injury may result, in part, from its antioxidant effect, which inhibits lipid peroxidation.

Role of oxygen radicals in indomethacin-induced gastric mucosal microvascular injury in rats

To investigate the pathogenesis of indomethacin-induced gastric mucosal injury, vascular injury was examined in the rat using Evans blue and monastral blue vascular tracers. Extravasation of intravenously injected Evans blue into the gastric mucosa was used as an indicator of vascular permeability. Monastral blue was used to demonstrate vascular injury morphologically. The extravasated content of Evans blue significantly increased and reached the maximum at 2 h after indomethacin administration. The increase in Evans blue content was significantly inhibited by the pretreatment with superoxide dismutase (SOD) and SOD + catalase, but not with catalase alone. Monastral blue-labeled damaged endothelial cells in the gastric mucosa also increased at 2 h after indomethacin administration, which increase was reduced by pretreatment with SOD and SOD + catalase. These results indicate that oxygen radicals, including the superoxide radical, play an important role in the microvascular injury induced by indomethacin, which in turn plays a primary role in the development of gross hemorrhagic erosions.

Role of active oxygen, lipid peroxidation, and antioxidants in the pathogenesis of gastric mucosal injury induced by indomethacin in rats

The roles of active oxygen, lipid peroxidation, and the antioxidative defence mechanism in gastric mucosal injury induced by treatment with indomethacin in rats were investigated. The total area of gastric erosions and concentration of lipid peroxides in the gastric mucosa increased with time after administration of indomethacin (20 mg/kg, orally). The alpha-tocopherol:total cholesterol ratio in serum was significantly decreased and the activity of glutathione peroxidase, an important enzyme to scavenger of lipid peroxides, was inhibited by the administration of indomethacin. Treatments with superoxide dismutase and catalase inhibited the increases in gastric mucosal erosions and lipid peroxides in the gastric mucosa, and the reduction of serum alpha-tocopherol. Treatment with these scavengers did not improve the decreased glutathione peroxidase activity. These findings suggest that active oxygen species and lipid peroxidation play an important part in the pathogenesis of gastric mucosal injury induced by indomethacin, and that the decreased glutathione peroxidase activity aggravated the injury due to accelerated accumulation of hydrogen peroxide and lipid peroxides in the gastric mucosal cell.

TAN-1120, a new anthracycline with potent angiostatic activity

A potent angiogenesis-inhibitory compound TAN-1120 was found to be produced by a Streptomyces species isolated from a soil sample. The producing organism was characterized as a new subspecies of S. triangulatus and named S. triangulatus subsp. angiostaticus subsp. nov. due to its specific ability to produce the compound. This substance was isolated as a red powder by a combination of organic solvent extraction, silica gel column chromatography and preparative HPLC using an ODS column. Its structure was elucidated by chemical reactions and spectral analyses to be a new baumycin-group anthracycline. Reduction of TAN-1120 gave two compounds, a deoxy derivative and baumycin A1. TAN-1120 showed remarkably potent angiostatic activity in two conventional angiogenesis assay systems in vivo, while doxorubicin and daunomycin had far weaker activity. It strongly inhibited proliferation of vascular endothelial cells did not prevent capillary cord formation in vitro by the endothelial cells on extracellular matrix-coated plates. TAN-1120 is one of the most potent angiostatic agents reported.

[Role of polymorphonuclear leukocytes (PMN) and active oxygen species in hyperthermia--antitumor effect of hyperthermia combined with rhG-CSF]

We have reported that polymorphonuclear leukocytes (PMN) and active oxygen species from PMN may play an important role in the mechanism of the antitumor effect of hyperthermia. At this time, we focused our experimental studies on rat AH109A carcinoma treated with hyperthermia combined with arterial injection of rhG-CSF. Rats with transplantable AH109A carcinoma at the hind leg received hyperthermia. These tumors showed mild suppression of further development only by hyperthermia. However, when arterial injection of rhG-CSF was applied together with hyperthermia, marked suppression of tumor development was observed. Our data suggest that hyperthermia combined with rhG-CSF is closely related to the generation of free radical-mediated tumor cell killing, and it can be an effective treatment for cancer.

A synthetic method suitable for the rapid preparation of 13N-labeled dermorphin analogue, H-Tyr-D-Met(O)-Phe-Gly-NH2 (SD-62)

A synthetic method suitable for the preparation of 13N-labeled dermorphin analogue, H-Tyr-D-Met(O)-Phe-Gly-NH2 (SD-62), was established; i.e., SD-62 was synthesized by a 5 min treatment of the active ester precursor with ammonia. When the 13N-labeled SD-62, prepared by this method with [13N]ammonia, was administered into mice, the time profile of the radioactivity accumulation in the brain paralleled well that of the analgesic activity.

TAN-931, a novel nonsteroidal aromatase inhibitor produced by Penicillium funiculosum No. 8974. I. Taxonomy, fermentation, isolation,characterization and biological activities

A novel nonsteroidal aromatase inhibitor, TAN-931, was isolated from the culture filtrate of a soil isolate fungus, No. 8974. The strain was identified as Penicillium funiculosum No. 8974. TAN-931 inhibited human placental and rat ovarian aromatase activity, and the IC50 value was 17.2 and 162 microM, respectively. The inhibition of human placental aromatase was uncompetitive with respect to androstenedione conversion with a Ki value of 40 microM. When TAN-931 was subcutaneously administered at doses of 25, 50 and 100 mg/kg (once/day, x4) to 20-day-old female Sprague-Dawley rats treated with gonadotropin, the plasma estradiol-17 beta level and the weight of ovaries and uterus were markedly reduced in a dose-dependent manner. The in vivo inhibitory activity of TAN-931 was more potent than that of 4-hydroxyandrostenedione. Consecutive administration of TAN-931 (100 mg/kg, sc, twice/day, x 7) to 9-week-old male Sprague-Dawley rats did not induce any adrenal hypertrophy even though administration of aminoglutethimide caused 2-fold enlargement of the adrenal under the same conditions. Specific binding of TAN-931 to the estrogen receptor from a human breast cancer cell line, MCF-7, was not detected.

[Acute unclassified leukemia with bone marrow necrosis]

Massive bone marrow necrosis was seen in a 42-year-old male with acute leukemia. In December, 1988, on admission, laboratory data revealed pancytopenia and a high level of serum LDH and ALKP. Bone marrow aspiration resulted in dry-tap and showed bone marrow necrosis in the bone marrow biopsy specimen. A bone marrow scintigraphy with 111In faintly visualized the bone marrow but visualized area was expanded in the extremities compared with normal subjects. The second bone marrow biopsy showed proliferation of blasts. In the middle of March, blasts began to appear in peripheral blood. The blasts were cytochemically negative for POX, Es, PAS, AcP, TdT and had surface markers CD3-, CD19-, CD33-, CD13-, LCA-, HLA-DR-. Even by investigation on rearrangement of the immunoglobulin heavy chain region, an origin of the blasts could not be determined. In April, the number of blasts in peripheral blood increased and hepatosplenomegaly developed rapidly. Therefore, he was put on the chemotherapy with vincristine and prednisolone, but he died of cerebral hemorrhage. The autopsy revealed widespread bone marrow necrosis. It has rarely been reported that massive bone marrow necrosis is found prior to the occurrence of acute unclassified leukemia.

Deprotection of the S-trimethylacetamidomethyl (Tacm) group using silver tetrafluoroborate: application to the synthesis of porcine brain natriuretic peptide-32 (pBNP-32)

Silver tetrafluoroborate (AgBF4) in trifluoroacetic acid (TFA) has been found to cleave the S-trimethyl-acetamidomethyl (Tacm) group or the S-acetamidomethyl (Acm) group without affecting other functional groups in a peptide chain. A newly isolated porcine brain natriuretic peptide-32 (pBNP-32) was synthesized by the combined use of the S-Tacm group and AgBF4 deprotection. The synthetic pBNP-32 was obtained in better yield by the AgBF4 procedure than by the standard I2 procedure. The synthetic pBNP-32 has the highest chick rectum relaxant activity among the known members of the atrial natriuretic peptide-brain natriuretic peptide (ANP-BNP) families. Somatostatin was also synthesized by the Fmoc-based solid-phase method using S-Tacm and AgBF4. In this synthesis, the recently developed reagent tetrafluoroboric acid (HBF4) was applied to cleave the peptide from the resin.

[A case of complete remission obtained with etoposide cis-platinum combination chemotherapy in advanced testicular cancer]

A 49-year-old male patient was admitted to our hospital complaining of right scrotal mass. Serum tumor markers, HCG, beta-HCG and AFP, were all elevated. After right high inguinal orchiectomy, a pathological report revealed a mixed-type germ cell tumor, which was composed of choriocarcinoma, embryonal carcinoma and seminoma. Because of persistent elevation of these tumor markers, RPLND was performed. There were viable tumor cells in the dissected lymph node specimens. As pulmonary metastases developed after RPLND, the patient was treated with 3 courses of VAB-6 combination chemotherapy (vinblastine, actinomycin-D, cyclophosphamide, bleomycin and cis-platinum). Pulmonary metastases disappeared and tumor markers returned to normal range except for moderate elevation of serum HCG. Two months later, pulmonary metastases developed again with re-elevation of tumor markers. Four courses of EP salvage chemotherapy (etoposide and cisplatinum) were given. After EP chemotherapy, the patient was given etoposide orally for about 7 months. During this period, no abnormality was found except for slight elevation of serum HCG. Five months after discontinuing chemotherapy, serum HCG returned to normal and complete remission was obtained.

Synthesis of porcine brain natriuretic peptide-32 using silver tetrafluoroborate as a new deprotecting reagent of the S-trimethylacetamidomethyl group

Silver tetrafluoroborate (AgBF4) in trifluoroacetic acid (TFA) has been found to cleave the S-trimethylacetamidomethyl (Tacm) group or the S-acetamidomethyl (Acm) group without affecting other functional groups in the peptide chain. Newly isolated porcine brain natriuretic peptide-32 (pBNP-32) was synthesized using AgBF4 and Cys(Tacm) derivatives. The synthetic pBNP-32 had the highest chick rectum relaxant activity among the ANP-BNP families.