Leiomyomatosis peritonealis disseminata occurring in a postmenopausal woman: report of a case

Leiomyomatosis peritonealis disseminata (LPD) is a rare condition, reported to occur chiefly in premenopausal women. In fact only five cases of LPD in postmenopausal women have been documented in the English literature. We report herein a case of LPD occurring in a postmenopausal woman who had undergone a total hysterectomy 15 years earlier and received no subsequent hormonal therapy. At laparotomy, a cystic mass measuring 10.0 x 12.0 cm was found adhering to the jejunum. There were also innumerable tumor nodules ranging from 0.5 to 5.0 cm in diameter attached to the antimesenteric borders of the intestine and the parietal peritoneum. We resected the cystic main tumor together with 20 cm of jejunum to release the intestinal obstruction. Several daughter tumors were also resected as biopsies for histological examination. Histologically, the lesions were multiple and consisted of proliferating smooth muscle cells with rod-like nuclei showing extremely rare mitotic figures, confirming a diagnosis of LPD.

Mitochondrial rDNA phylogeny of the asteroidea suggests the primitiveness of the paxillosida

Asteroids display four distinct modes of developmental patterns: the indirect mode, the nonbrachiolarian mode, the direct mode, and the mode with a barrel-shaped larva. Among them the former two are planktotrophic, whereas the latter two are lecithotrophic. The direct mode and the mode with a barrel-shaped larva are thought to have evolved from the more primitive planktotrophic mode, the nonbrachiolarian and the indirect mode, respectively. However, whether the nonbrachiolarian mode or the indirect mode is the more primitive in asteroids is unresolved, despite discussion since early this century. A key aspect of this problem is the phylogenetic status of paxillosidans, since the nonbrachiolarian mode and the mode with a barrel-shaped larva are seen only in paxillosidans. To resolve this problem, we performed a molecular phylogenetic study of asteroids, based on the nucleotide sequences of mitochondrial rDNAs. Phylogenetic trees support a close relationship between the Asterinidae and the Solasteridae. We suggest that the paxillosidans are not a monophyletic group; rather, the Luidiidae (one family of Paxillosida) is a sister group to the rest of the asteroids. Although some aspects of our results contradict a recent study by Lafay et al. (1995, Syst. Biol. 44: 190-208) based on 28S rRNA sequences, both studies agree on a paraphyletic nature for the paxillosidans. We conclude that characters shared by paxillosidans are primitive; hence the primitive mode of development in asteroids is the nonbrachiolarian mode.

[Effects of intravitreal levofloxacin on the rabbit retina]

Effects of intravitreal injection of levofloxacin (LVFX) on the electroretinogram (ERG), visual evoked potential (VEP), and retinal histology were studied in 23 albino and 23 pigmented rabbits to establish the non-toxic intravitreal dosage of LVFX. Doses of 200, 500, 1,000 or 2,000 micrograms of LVFX were injected intravitreally. The ERG and VEP were recorded before injection, and 3 hours, 2 days, 1 week, 2 weeks and 4 weeks after injection. The oscillatory potential transiently deteriorated with 1,000 and 2,000 micrograms doses of LVFX in albino and pigmented rabbits. No ERG changes were observed with 200 and 500 micrograms doses. No abnormal changes were observed in the VEP or retinal histology with any doses of LVFX. These results indicate that intravitreal injections of 200 and 500 micrograms of LVFX are nontoxic to the rabbit retina.

Free radical scavenging activity of the Japanese herbal medicine toki-shakuyaku-san (TJ-23) and its effect on superoxide dismutase activity, lipid peroxides, glutamate, and monoamine metabolites in aged rat brain

The free radical scavenging activity of the Japanese herbal medicine, Toki-Shakuyaku-San (TJ-23; TSUMURA & Co., Tokyo, Japan), was examined using electron spin resonance (ESR) spectrometry. TJ-23 scavenged 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), superoxide (O2-), and hydroxyl radicals (.OH) dose-dependently. It also diminished carbon centered radicals (.C) generated by oxidative stress and inhibited thiobarbituric acid-reactive substances (TBARS) formation in mouse cortex homogenate. In addition, the effect of TJ-23 on the concentration of neurotransmitters and TBARS formation, and superoxide dismutase (SOD) activity in the cortex, hippocampus and striatum of the aged rat brain was studied. The concentrations of the metabolites of monoamines, glutamate and glutamine were decreased by 4 weeks of oral administration of TJ-23. The SOD activity of mitochondrial fraction was increased and TBARS formation was significantly suppressed. These results suggest that TJ-23 has an antioxidant action and would have a prophylactic effect against free radical-mediated neurological diseases associated with aging.

Specific regulation of gene expression by antisense nucleic acids: a summary of methodologies and associated problems

Gene therapy based on gene-specific nucleic acids has moved from theory to a practical possibility in a very short time. The new DNA and RNA therapeutic reagents are intended to stop the growth of cancerous cells or the production of viruses. At the practical level, the efficacy of antisense oligomers as therapeutic reagents has been carefully examined in various clinical contexts. For the efficient use of antisense nucleic acids as pharmaceutical agents, a complete analysis of their mechanisms of action is necessary. The use of antisense oligomers always involves the following problems: basepair specificity, stereoisomer specificity, stability and resistance to nucleases of sense-antisense duplexes, permeability of the cell membrane and targeting of the oligomer, safety, and the preparation of large amounts of oligomer. Herein, we review the basic concepts and problems associated with the exploitation of antisense technology. We have identified a new transcription factor triple-helix-binding zinc-finger protein-1 (THZif-1) induced by antisense c-myc RNA in the antisense-transformed HL60 cells. The encoded protein functions as the repressor of c-myc to achieve the reduction of the endogenous expression of c-myc gene. Therefore, the introduction of THZif-1 gene into HL60 cells in conjunction with antisense c-myc oligomers may result in the efficient repression of the expression of the c-myc gene. The molecular features of this factor are herein discussed.

[Unclassified chronic myeloproliferative disorder (Ph negative/bcr rearrangement negative CML) with late appearing Philadelphia like chromosome]

A 48-year-old male was diagnosed to be unclassified chronic myeloproliferative disorder (UCMPD)/Ph negative bcr rearrangement negative (Ph-/bcr-) CML by hematological, cytogenetical and DNA analyses (Jpn. J. Clin. Hematol. 33(4): 525-531, 1992). Three years and a half after the diagnosis of UCMPD/Ph-bcr- CML, Ph chromosome was observed in 17 of 20 examined cells. Hematological findings showed a transformation into blast crisis. The late appearing of Ph in a case of UCMPD/Ph1-bcr- CML described here is rare. Southern blot analysis using 3' and 5' bcr probe showed no bcr rearrangement. Analyses of BCR/ABL chimeric RNA by RT-PCR method were negative in both of Major- and Minor BCR/ABL chimeric RNA. In the present case it is speculated that Ph is developed as the result of multistep progression and also speculated that the breakpoint at BCR gene differs from Major- and Minor-bcr in usual Ph+CML and de nove Ph+ ALL. Therefore, it may be reasonable that the present case is understood to be a case with late appearing Ph-like chromosome.

Effect of TJ-960 (a Japanese herbal medicine) on free radical changes within an iron-induced focal epileptogenic region in rat brain measured by in vivo L-band electron spin resonance

In vivo L-band electron spin resonance (ESR) system was used to measure the decay of nitroxide radicals in the living rat cerebrum containing a cortical area with an iron-induced epileptogenic region. Carbamoyl-PROXYL (3-carbamoyl-2,2,5,5-tetramethyl-1-pyrrolinyloxy) was injected intraperitoneally. The decay of nitroxide radicals in the iron-injected regions at the subacute stage of epileptogenesis was prolonged. The Japanese herbal medicine, sho-saiko-to-go-keishi-ka- shakuyakuto (TJ-960), a compound known to have free radical scavenging activity, inhibited the delay of nitroxide radical decay in the rat cerebrum with an iron-induced epileptic focus following injection of carbamoyl-PROXYL. TJ-960 did not affect the decay of nitroxide radicals in the control rats' brain. These data show that TJ-960 has the scavenging activity for free radicals generated within an iron-induced epileptogenic regions of rat brain.

Cervical Castleman's disease associated with benign M-proteinemia: report of a case

We report the unusual case of a 77-year-old man with cervical Castleman's disease associated with benign M-proteinemia. The patient was found to have an anterior cervical tumor during a follow-up examination after surgery for early gastric cancer, at which time blood biochemistry tests revealed M-proteinemia at the position of beta-globulin with a high level of IgG and low levels of IgA and IgM. Serum protein immunoelectrophoresis revealed M-protein consisting of the IgG-k chain, and urine protein immuno-electrophoresis demonstrated Bence Jones protein consisting of the chain. No abnormalities were noted in bone marrow aspiration or bone scintigram. The results of imaging and fine-needle aspiration biopsy of the tumor led to a pre-operative diagnosis of cervical malignant lymphoma with suspected M-proteinemia derived from this disease, and resection of the anterior cervical tumor with bilateral neck dissection was performed. Histopathological examination subsequently demonstrated four mixed-type tumors of Castleman's disease. The pathogenesis of Castleman's disease remains unknown; however, we speculate that the complication of benign M-proteinemia in this patient was not incidental, but caused by an underlying immunological abnormality of the B cells.

Protease activity appeared after trypsin treatment of the purified vitellogenin from eel Anguilla japonica

Density gradient ultracentrifugation and anion-exchange chromatography combination were effective for the purification of the eel vitellogenin from the plasma of estradiol-treated eels. The vitellogenin was very high density glycolipoprotein (P = 1.27 g/ml) and its apolipoprotein was M(r) 196 k in both reduced and non-reduced conditions by SDS-PAGE. The major lipid component was phospholipid. The N-terminal amino-acid sequence of the vitellogenin was as follows: (Ac)Thr-Pro-Ala-Leu/Ala-Asp-Tyr. Amino-acid composition of the eel vitellogenin was similar to those of other teleosts. The protease activity appeared in the trypsinized vitellogenin, but was not detected in the purified vitellogenin. The protease was separated from the used trypsin and the other cleaved vitellogenin by a dextran sulfate cellulose column. The molecular weight of the protease was determined by zymogram using SDS-polyacrylamide gel containing casein and was 50 k. It was concluded that the eel vitellogenin possesses the protease activity as a latent form.

Distribution of the different subtypes of hepatitis C virus in Japan and the effects of interferon: a nationwide survey

Interferon (IFN) is now commonly used for the treatment of type C hepatitis; however, its effects differ depending upon the subtype of hepatitis C virus (HCV) being treated. It has been recently confirmed in many studies in Japan that the effectiveness of IFN treatment is poor in patients having type 1b and better in patients having type 2a HCV. However, the effects of IFN treatment on other subtypes of HCV were not clear because of the small number of patients in each hospital. In the present study, the effects of IFN treatment in patients with other HCV subtypes were analysed from nationwide data collected in Japan using a standard questionnaire. From this questionnaire, local differences in the distribution of HCV subtypes in Japan were also analysed. A standard questionnaire, consisting of questions about the number of patients with chronic type C hepatitis with different HCV subtypes and the number of patients showing different responses to IFN treatment, was sent to over 40 study groups in Japan. Answers to the questionnaire concerning HCV subtypes and the effects of IFN treatment were obtained from 26 and 22 hospitals, respectively, throughout Japan. The incidence of HCV type 1b was highest in the Kinki area (south-central Japan). The incidence of type 1b HCV decreased in parallel with distance from this area. The mortality rates of hepatic cancer in different areas were significantly correlated with the incidence of HCV type 1b. The efficacy of IFN treatment was significantly better for both types 2a and 2b HCV than for type 1b HCV; the efficacy of IFN treatment was poor in the mixed type of 1b and 2a and tended to be better in type 1a. The efficacy of IFN treatment for other types of HCV was also better. These results indicate that there are local differences in the distribution of HCV subtypes in Japan and that these differences may be closely associated with the clinical features of HCV-related liver disease. The efficacy of IFN treatment was significantly poorer in patients with the 1b-related type HCV than in patients with other types of HCV.

Relationship between hepatocellular carcinoma and subtypes of hepatitis C virus: a nationwide analysis

Although hepatitis C virus (HCV) has now been classified into several subtypes, the clinical significance of HCV subtypes is not well known. Typing of HCV is now routinely performed in Japan. In the present study, HCV subtypes in hepatocellular carcinoma (HCC) patients were analysed from nationwide data collected in Japan using a standard questionnaire. Answers to the questionnaire concerning HCV subtypes in patients with chronic hepatitis (CH), liver cirrhosis (LC) and HCC were obtained from 14 hospitals. The prevalence of the 1b-related subtype, which includes the mixed subtype of 1b and 2a or 2b, in patients with LC and HCC in each hospital was higher than in patients with CH, with few exceptions. However, the differences were not statistically significant because of the small number of patients in each hospital. In summarized data from all 14 hospitals, the 1b-related subtype was found in 1370 of 1922 patients with CH (71.2%). In 356 LC and 426 HCC patients, the prevalence of the 1b-related subtype was 79.8 and 80.5%, respectively. The prevalence of the 1b-related subtype in patients with LC and HCC was significantly higher than in patients with CH. There was no significant difference between the prevalence of the 1b-related subtype in patients with HCC and LC. These results indicate that the oncogenic activity of subtype 1b, although not yet clearly characterized, may be stronger than subtypes 2a and 2b.

[Detection and identification method of three mycobacterium species and genus specific detection by polymerase chain reaction and DNA hybridization with alkaline phosphatase labeled oligonucleotide probe]

Rapid detection and identification method of mycobacteria from specimen with infected mycobacteriosis was established by the combination of polymerase chain reaction and alkaline phosphatase labeled oligonucleotide probe (PCR-ALPDH). We prepaired four kinds of probes: Mycobacterium tuberculosis complex, M. avium, M. intracellulare, and mycobacterial-probe other than tuberculosis. PCR-ALPDH was compared with conventional methods using 234 specimens which suspected mycobacteriosis. In culture, 68 specimens (29.1%) were positive and 166 specimens (70.9%) were negative. In PCR-ALPDH, 88 specimens (37.6%) were positive and 146 specimens (62.4%) were negative. In 68 specimens which were positive in culture, the agreement of results of conventional identification and PCR-ALPDH for each probes were: 39/40 (PCR-ALPDH/Culture, 97.5%) in M. tuberculosis 5/9 (55.6%) in M. avium, 6/6 (100%) in M. intracellulare and 22/28 (88.6%) in MOTT isolation. Among 166 negative culture specimens, 27 specimens were positive in PCR-ALPDH. The results indicated that PCR-ALPDH method was applicable for the establishment of rapid and sensitive mycobacterial diagnostic system.

Fulminant hepatitis caused by hepatitis C virus during treatment for multiple sclerosis

A 55-year-old woman was treated at our hospital for multiple sclerosis. Therapy consisted of glucocorticosteroids and cyclosporin. In the 7th week after these drugs were discontinued the patient developed acute liver failure due to fulminant hepatitis (FH) and died. Post-mortem examination showed massive liver necrosis. Serologic examination was negative for hepatitis B virus-related markers. Antihepatitis C virus (anti-HCV) antibody and serum HCV RNA were negative on admission, but HCV RNA appeared concurrently with the onset of FH. Although HCV infection rarely causes FH, it was considered to be the cause of FH in this patient, since there were no other causes of acute liver injury. We suspect that underlying immunologic abnormalities in conjunction with HCV infection may have precipitated the FH.

[Study of medical economy in home parenteral nutrition]

The authors studied the relation between home parenteral nutrition (HPN) and medical economy. The items of study are 1) cost benefit of HPN compared with TPN, 2) hospital intention to promote HPN, 3) economical demerits for outpatients receiving HPN.

RESULTS

1) HPN had the advantage of cost benefit compared with TPN in reimbursement; however, hospitals did not have such an intention. 2) It is necessary for advanced home care to improve reimbursement in the health insurance system; and in the existing situation, hospitals do not profit from HPN. 3) Home care companies are unprofitable because of nursing visits and reimbursement issues which do not ease legal restrictions. 4) HPN in the present situation depends on the ability of patients to pay and the ability of care givers to provide care.

Glucose stimulation of insulin release in the absence of extracellular Ca2+ and in the absence of any increase in intracellular Ca2+ in rat pancreatic islets

Insulin secretion has been studied in isolated rat pancreatic islets under stringent Ca(2+)-depleted, Ca(2+)-free conditions. Under these conditions, the effect of 16.7 mM glucose to stimulate insulin release was abolished. Forskolin, which activates adenylyl cyclase, also failed to stimulate release in the presence of either low or high glucose concentrations. A phorbol ester (phorbol 12-myristate 13-acetate; PMA) increased the release rate slightly and this was further increased by 16.7 mM glucose. Remarkably, in the presence of both forskolin and PMA, 16.7 mM glucose strongly augmented insulin release. The augmentation was concentration dependent and monophasic and had a temporal profile similar to the "second phase" of glucose-stimulated insulin release, which is seen under normal conditions when Ca2+ is present. Metabolism is required for the effect because mannoheptulose abolished the glucose response. Other nutrient secretagogues, alpha-ketoisocaproate, and the combination of leucine and glutamine augmented release under the same conditions. Norepinephrine, a physiological inhibitor of insulin secretion, totally blocked the stimulation of release by forskolin and PMA and the augmentation of release by glucose. Thus, under the stringent Ca(2+)-free conditions imposed, the stimulation of insulin release by forskolin and PMA, as well as the augmentation of release by glucose, is under normal physiological control. As no increase in intracellular [Ca2+] was observed, the results demonstrate that glucose can increase the rate of exocytosis and insulin release by pancreatic islets in a Ca(2+)-independent manner. This interesting pathway of stimulus-secretion coupling for glucose appears to exert its effect at a site beyond the usual elevation of intracellular [Ca2+] and is not due to an activation by glucose of protein kinase A or C.

SSCP analysis of pig mitochondrial DNA D-loop region polymorphism

The sequence polymorphism that occurs in the mitochondrial DNA (mtDNA) displacement (D)-loop region is useful as a cytoplasmic DNA marker. We cloned the mtDNA D-loop regions of five breeds of pig by polymerase chain reaction (PCR) and determined their sequences. The sequence diversities in D-loop regions among five breeds of pig were located in the starting area of heavy-strand replication. From these sequences, we designed primers for PCR-mediated single-strand conformation polymorphism (PCR-SSCP) analysis that amplified the most polymorphic 227 bp fragment of the D-loop region. The results of PCR-SSCP analysis clearly showed that four types of polymorphism (A to D) are found in Landrace (A), Large White (A, B), Duroc (A), Göttingen miniature pig (B) and Meishan (C, D). The same polymorphisms were also detected from each porcine embryo by this method. Our results show that PCR-SSCP analysis is useful in detecting polymorphisms in the D-loop region of pigs and pig embryos.

Effect of lithium on serum calcium level and parathyroid function in manic-depressive patients

The purpose of this study is to find out whether hypercalcemia and hyperparathyroidism are rare or not in manic-depressive patients taking lithium carbonate. The subjects were 13 patients receiving lithium and 19 healthy subjects not receiving it as normal controls. Serum ionized calcium (Ca++), serum parathyroid hormone (PTH), urinary calcium and cyclic AMP(cAMP) were measured. Cervical ultrasonographic examination was also performed. The mean serum Ca++ level in the lithium administered group was significantly higher than that in the control group (P < 0.02). There was no significant difference between the serum PTH levels in the two groups. The mean urinary calcium level in the lithium administered group was below the normal range, but the mean urinary of cAMP level was within the normal range. Although a parathyroid cyst was found in one lithium administered patient on ultrasonographic examination, no swelling of the parathyroid gland was observed in the other patients in the lithium administered group or in any of the control subjects. In the present study, no distinct hyperparathyroidism was found in the patients in the lithium administered group. Lithium administration affects calcium metabolism in manic-depressive patients and hypercalcemia seems to be one of the complications needing attention at the time of lithium administration.

Purification and characterization of cytoplasmic dynein of rabbit liver

Cytoplasmic dynein is a microtubule-dependent motor protein, which plays a role in intracellular transport. However, there have been few studies regarding the role of cytoplasmic dynein in the liver. Purification of cytoplasmic dynein from rabbit liver took advantage of the affinity of microtubule-dependent motor proteins for microtubules. Purified dynein contained heavy chain (450 kDa), intermediate chain (75 kDa), light chains (45-58 kDa) and dynactin (150 kDa). The subunit composition was consistent with previously reported data on brain cytoplasmic dynein. Microtubules prepared from bovine brain were driven by purified cytoplasmic dynein from rabbit liver, and movements of microtubules were visualized by video-enhanced differential interference contrast microscopy. The mean velocity of the motile microtubules was 1.09 +/- 0.13 microns/s. Our study provides evidence of rapid intracellular transport in hepatocytes controlled by cytoplasmic dynein.

Ruptured subcapsular giant hematoma of the spleen as a complication of chronic pancreatitis

We present a 63-year-old man with chronic pancreatitis and the rare complication of giant subcapsular splenic hematoma. The hematoma showed no size reduction for 6 weeks. Then, the hematoma was infected with pseudomonas aeruginosa after the recurrence of the pancreatitis, and it finally ruptured. This case suggested that in cases of giant subcapsular splenic hematoma with chronic pancreatitis reductive pressure treatment should be administered as early as possible.

Time course of action of pertussis toxin to block the inhibition of stimulated insulin release by norepinephrine

Male Sprague-Dawley rats were injected ip with 1 microgram pertussis toxin (PTX)/100 g BW. The rats were killed 24, 48, and 72 h after injection, and their pancreases were removed. At each time point, insulin secretion by isolated islets was measured under basal and glucose-stimulated conditions and in the absence and presence of norepinephrine. cAMP levels were measured under basal and forskolin-stimulated conditions in the absence and presence of norepinephrine. PTX-induced ADP ribosylation of Gi/Go proteins in vivo was monitored by ADP ribosylation in vitro using PTX and 32P-labeled NAD and also by Western blotting. At 24 h, 1 microM norepinephrine inhibited glucose-stimulated insulin secretion by 92% in the control islets, but by only 53% in the PTX-treated islets; at 48 h, norepinephrine still inhibited secretion (by 40%) in the PTX-treated islets; at 72 h, the inhibitory effect of norepinephrine was abolished. Therefore, contrary to recent suggestions, all of the effect of norepinephrine to inhibit insulin release is PTX sensitive. The effects of PTX on the ability of norepinephrine to lower cAMP levels were similar to those observed for the inhibition of insulin release. PTX partially blocked the effect of norepinephrine to lower cAMP levels at 24 and 48 h, and the block was complete after 72 h. The extent of the in vivo ADP ribosylation of the Gi/Go proteins, monitored at each time point by in vitro [32P]ADP-ribosylation and Western blotting, demonstrated a profound ADP ribosylation at 48 and 72 h. As detected by Western blotting, the rates of ADP ribosylation by PTX and the onset of decreased expression varied among the different G-proteins. G alpha o was virtually eliminated after only 24 h of PTX treatment. G alpha i2 was markedly affected by 48 h; G alpha i3 was little affected until 72 h.

[Studies on antiulcer agents. III. Synthesis and antiulcer activity of phenylpropanol derivatives]

It was found that (+/-)ethyl 2-[2-(3-hydroxypropyl)-4-oxocyclohexylidene]-propionate (1), (+/-)ethyl 2-[2-(3-hydroxypropyl)-4,5-dimethoxyphenyl]propionate (2) and (+/-)3-[2-(3-hydroxypropyl)-4,5-dimethoxyphenyl]-2-butanone (3) had excellent antiulcer activities. In order to study structure-activity relationships, (+/-)2-[(3-hydroxypropyl)phenyl]cyclopentanone derivatives (4, 5) and (+/-)2-[(3-hydroxypropyl)phenyl]cyclopentanol derivatives (6, 7) were synthesized and tested for antiulcer activities. As a result, (+/-)2-[2-(3-hydroxypropyl)-4-methoxy-5-(2- piperidinoethoxy)phenyl]cyclopentanone (5k) exhibited potent antiulcer activities.

Mastoparan increases the intracellular free calcium concentration in two insulin-secreting cell lines by inhibition of ATP-sensitive potassium channels

The mechanisms underlying mastoparan-induced elevation of the intracellular free calcium concentration ([Ca2+]i) were investigated in the insulin-secreting cell lines RINm5F and HIT. In both cell types, micromolar concentrations of mastoparan induced a prompt increase of [Ca2+]i, measured as an increase in fura-2 fluorescence. This response was dependent on extracellular calcium entry and was suppressed by organic calcium channel blockers; the increase of [Ca2+]i caused by high glucose concentrations or tolbutamide was not enhanced by mastoparan. These data indicate the involvement of voltage-dependent calcium channels and suggest that depolarization, rather than a direct effect on the channels, mediates the response to mastoparan. This proposition was supported by the observation that whole-cell calcium currents measured using the nystatin-permeabilized patch technique were not affected by mastoparan. Mastoparan-induced depolarization was observed using the potentiometric indicator bis-oxonol, and it was shown not to be additive with the depolarization induced by high glucose concentrations or tolbutamide. The mechanism underlying mastoparan-induced depolarization was identified in single-channel patch-clamp experiments, where it was shown that mastoparan caused closure of ATP-sensitive potassium channels [K(ATP) channels] in cell-attached and excised membrane patches. Responsiveness to mastoparan in excised patches demonstrated the membrane-delimited character of K(ATP) channel inhibition. The observation that the response persisted in the absence of exogenous GTP and in the presence of 250 microM GDP or guanosine-5'-O-(2-thio)diphosphate suggested that this effect is not mediated via enhancement of G protein activity. Partial suppression of channel activity by mastoparan did not prevent the action of tolbutamide, which fully suppressed the remaining activity in excised patches. In summary, the increase of [Ca2+]i in the insulin-secreting tumor cell lines RINm5F and HIT in response to mastoparan is mediated via G protein-independent suppression of K(ATP) channel activity, cell depolarization, and activation of voltage-dependent calcium channels.

Antioxidant effects of "beta catechin"

The free radical scavenging effect of "beta catechin", an antioxidant preparation containing green tea extract, ascorbic acid, sunflower seed extract, dunaliella carotene and natural vitamin E, was evaluated. Two techniques were used: electron spin resonance (ESR) spectrometry to measure radical-scavenging activity, and measurement of its effect on iron-induced lipid peroxidation in brain. A 0.05% solution of "beta catechin" completely scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals (6.1 x 10(15)spins/ml). A 10% solution of "beta catechin" completely scavenged superoxide (4.2 x 10(15) spins/ml) generated by the hypoxanthine-xanthine oxidase system. An undiluted solution of "beta catechin" scavenged about 90% of hydroxyl radicals (3.5 x 10(15) spins/ml) generated by the Fenton reaction. "beta catechin"s effect on the accumulation of thiobarbituric acid-reactive substances (TBARS) was evaluated from tissue obtained from the ipsilateral cortex of FeCl3-induced epileptic rats. Oral administration of "beta catechin" (1 or 2ml/kg body weight) both inhibited TBARS formation and increased the activity of superoxide dismutase (SOD) in the ipsilateral cortex 30 min after iron-salt injection into the left sensory motor cortex. These data suggest that "beta catechin" has an antioxidant effect and may have a prophylactic effect against aging and other neurological diseases related to free radical mechanisms.