TENS Alleviates Muscle Weakness Attributable to Attenuation of Ia Afferents.

Quadriceps weakness is a notable problem following knee damage. Research has shown effectiveness of TENS in improving Quadriceps weakness associated with arthrogenic muscle inhibition. However, these studies were not focused upon short term delivery of TENS, nor did they examine the potential mechanism(s). The present study examined the effect of 25-30 s of TENS upon weakness induced temporarily by a prolonged vibration. Subjects performed eccentric MVCs under 2 conditions (TENS and no-TENS). First, MVC was measured at baseline. For the TENS condition, TENS was applied to each subject's knee joint during a second MVC measurement after vibration. For no-TENS condition, TENS was not applied during the 2nd MVC measurement. MVC between pre-and post-vibration stimulation were compared across the 2 conditions. The results showed that MVC and EMG of TENS-condition was larger than that of no-TENS condition. Our results suggest that TENS could partially restore α-motoneuron activation, despite the induced dysfunctional γ-loop. These results suggest that mechanisms independent of the γ-loop such as a direct facilitation of the QF α-motoneuron pool by a long latency spinal-reflex and/or supraspinal mechanisms appear more likely to be responsible. The findings provide further support for utilizing TENS, even when γ-loop dysfunction is present following joint damage.

Application of residual polysaccharide-degrading enzymes in dried shiitake mushrooms as an enzyme preparation in food processing.

OBJECTIVE: To examine the activities of residual enzymes in dried shiitake mushrooms, which are a traditional foodstuff in Japanese cuisine, for possible applications in food processing. RESULTS: Polysaccharide-degrading enzymes remained intact in dried shiitake mushrooms and the activities of amylase, ß-glucosidase and pectinase were high. A potato digestion was tested using dried shiitake powder. The enzymes reacted with potato tuber specimens to solubilize sugars even under a heterogeneous solid-state condition and that their reaction modes were different at 38 and 50 °C. CONCLUSION: Dried shiitake mushrooms have a potential use in food processing as an enzyme preparation.

A novel non-antibacterial, non-chelating hydroxypyrazoline derivative of minocycline inhibits nociception and oedema in mice.

BACKGROUND AND PURPOSE: Many in vitro and fewer in vivo studies have shown that tetracyclines present anti-inflammatory activity. We investigated if a novel non-antibacterial, non-chelating hydroxypyrazoline derivative of minocycline, 12S-hydroxy-1,12-pyrazolinominocycline (PMIN), also induced antinociceptive and anti-inflammatory effects. EXPERIMENTAL APPROACH: Antibacterial effects against a minocycline-sensitive Staphylococcus aureus strain were evaluated by applying a cylinder-plate agar diffusion technique. Antibacterial effects of diluted serum from mice pre-treated with minocycline or PMIN were also evaluated. Ca2+ binding activity was assessed by spectrophotometry. Formalin-induced nociceptive responses and carrageenan-induced paw oedema were evaluated in mice. The rota-rod apparatus was used to evaluate motor coordination. KEY RESULTS: Minocycline, but not PMIN, inhibited bacterial growth. Serum from mice treated with minocycline, but not with PMIN, also induced such an effect. The UV absorption spectrum of solutions of minocycline, but not those of PMIN, was markedly changed in the presence of Ca2+. Minocycline or PMIN inhibited both phases of formalin-induced nociception and carrageenan-induced paw oedema. It is unlikely that antinociception resulted from lack of motor coordination, as tetracycline did not impair the performance of mice on the rotating rod. CONCLUSIONS AND IMPLICATIONS: These results indicate that inhibition of nociception and oedema by tetracyclines is neither necessarily linked to antibacterial nor to Ca2+ chelating activities. This study supports the evaluation of the potential usefulness of PMIN in the treatment of painful and inflammatory diseases, as its lack of antibacterial and Ca2+ chelating activities might confer greater safety over conventional tetracyclines.

Secretory IgA, salivary peroxidase, and catalase-mediated microbicidal activity during hydrogen peroxide catabolism in viridans streptococci: pathogen coaggregation.

Viridans streptococci can kill methicillin-resistant Staphylococcus aureus (MRSA) through the production of hydrogen peroxide (H2O2). However, several hundred viridans streptococci cells are necessary to kill 1 cfu of MRSA. We analyzed the potency of bactericidal and fungicidal effector molecules induced by catabolism of H2O2 in the oral cavity. Secretory IgA (SIgA) and an unidentified salivary component bound Streptococcus sanguinis, a viridans streprococcus, and MRSA into coaggregates. In these coaggregates, salivary peroxidase and the MRSA catalase produced singlet molecular oxygen (1O2) from H2O2 produced by viridans streptococci. SIgA converted 1O2 into ozone, which has potent bactericidal and fungicidal activity. We calculated that <10 cfu of Streptococcus sanguinis were necessary to kill 1 cfu of MRSA in the coaggregate. SIgA, Aspergillus niger catalase, and H2O2 in saliva killed Candida albicans, which is highly resistant to reagent H2O2. Together with indigenous bacteria and innate immunity, SIgA potentially constitutes a novel system that may sustain oral homeostasis.

Drug evolution concept in drug design: 2. Chimera method.

The drug evolution method represents a novel approach towards efficient rational drug design by implementing the drug evolution concept to the creation and development of general chemical libraries with the purpose of allowing the identification of drug candidates with improved odds and lesser costs than the traditional drug design strategies. As another example of successful translation of the biological evolution into chemical evolution, the chimera method comprises the grafting of selected building blocks, identified through a basic search within a drug library, onto the same substitution sites on a rationally chosen scaffold. The method allows the creation of a library containing both drugs and prospective drug candidates without any priorly required knowledge on the pursued disease or molecular target. Two libraries having scaffolds derived from para-aminobenzoic acid and salicylic acid have exemplified the application of the chimera method. The validation of the method has been achieved through the high number of recognized drugs within the library, which exhibit in the same time a wide variety of therapeutic activities and interact with a broad spectrum of molecular targets. The drug-enriched chimera libraries are expected to provide a highly efficient access to novel drug candidates whose unspecified therapeutic effects should be further revealed through high-throughput screening.

Decrease in tetrahydrobiopterin as a possible cause of nephropathy in type II diabetic rats.

A decrease in renal synthesis of nitric oxide (NO) in the progression of diabetic nephropathy has been documented. As (6R)-5,6,7,8-tetrahydrobiopterin (BH4) is an essential cofactor of NO synthase, we investigated whether BH4 deficiency is involved in the pathogenesis of nephropathy. Ten-week-old Otsuka Long-Evans Tokushima Fatty (OLETF) rats were used as a type II diabetic model, and Long-Evans Tokushima Otsuka (LETO) rats as the healthy controls. OLETF rats were orally treated with BH4 (10 mg/kg daily) or with water from 10 to 61 weeks of age. In another experiment, OLETF rats were treated orally with a calcium channel blocker, benidipine (5 mg/kg daily), or with 0.3% carboxymethyl cellulose (nontreated) from 10 to 52 weeks of age. Proteinuria was observed periodically, and at the end of the study, BH4 level and GTP cyclohydrolase I (GTPCH) activity in the kidney were measured. Proteinuria was observed at 13 weeks of age in the OLETF rats, and deteriorated until 61 weeks of age. Supplemental BH4 reduced the proteinuria. At 52 weeks of age, GTPCH activity and the BH4 level were decreased in the plasma and kidneys of OLETF rats, whereas they were significantly higher in the benidipine group than in the nontreated group. Proteinuria was milder in the benidipine group than in the nontreated group, without a concomitant decrease in blood pressure. Histologically observed glomerulosclerosis was mild in the BH4 and benidipine groups. In type II diabetic rats, renal BH4 is considered to play a crucial role in the pathogenesis of diabetic nephropathy. Benidipine was found to preserve BH4 levels, suggesting therapeutic renoprotective effects.

Antibacterial activity of plants used in cooking for aroma and taste.

Thirty-three plants used in cooking for aroma and taste were examined for antibacterial activity against pathogens causing foodborne infections. Vibrio parahaemolyticus and Staphylococcus aureus were sensitive to many kinds of plant extracts, whereas Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Enteritidis populations decreased in only six, one, and three plant extracts, respectively. The polyphenol content in the plants was significantly different between the antibacterial plants and nonantibacterial plants, indicating that the polyphenols were related to the antibacterial action of these plants. Antibacterial activity of various concentrations of leaf extracts from Japanese persimmon, white cedar, and grape were investigated. Japanese persimmon and white cedar leaf extracts at low concentrations affected L. monocytogenes and V. parahaemolyticus rapidly. With grape leaf extract at low concentrations, the population of L. monocytogenes decreased similarly to Japanese persimmon and white cedar leaves. This study demonstrates that many plants used in cooking for aroma and taste contain polyphenols and exhibit antibacterial activity against foodborne pathogens.

IGF-I gene transfer by electroporation promotes regeneration in a muscle injury model.

The goal of this study was to determine whether insulin-like growth factor-I (IGF-I) gene delivery by electroporation promotes repair after muscle injury. An injury-repair model was created using mice in which a hamstring muscle was cut and sutured. A total of 50 microg of IGF-I DNA or green fluorescent protein (GFP) DNA (both in pCAGGS) was injected into the lesion and introduced into muscle cells by electrostimulation using an electric pulse generator. The number of regenerating muscle fibers in the IGF-I DNA group was significantly more than that in the GFP DNA group at 2 weeks after injection. The diameter of regenerating muscle fibers from the IGF-I DNA group was larger than that of the GFP DNA group at 4 weeks after injection. There was no significant difference in the serum IGF-I concentration between the IGF-I DNA group and the GFP DNA group at 1, 2, and 4 weeks after injection. However, muscle IGF-I concentration in the IGF-I DNA injection group was significantly greater than that in the GFP DNA injection group at 2 weeks after injection. These results demonstrated that the effects of enhanced IGF-I production were local and limited to the injected area. The ratio (injected/uninjected; intact) of the amplitude of compound muscle action potentials (CMAP) in the IGF-I DNA injection group was greater than that in the GFP DNA injection group at 4 weeks after injection and of the control group. In conclusion, IGF-I gene transfer by electroporation proved to be a simple, safe, inexpensive, and effective method to promote the regeneration of injured muscles in our injury model.

Promoter structure and gene expression of the mouse inositol 1,4,5-trisphosphate receptor type 3 gene.

Inositol 1,4,5-trisphosphate receptor type 3 (IP(3)R3) is a ubiquitously expressed IP(3)R gene in the IP(3)R gene family. We identified an upstream region of the mouse IP(3)R3 genomic DNA. Transcription start points for the IP(3)R3 gene were found to be located mainly at four sites between nucleotide position -325 and -285 relative to the first ATG codon. The major start point was mapped around -325. Transcription promotion ability was detected between -325 and -285 in an IP(3)R3 proximal promoter sequence. The promoter had no TATA-box but was highly GC-rich and contained two putative Sp1-binding sites. There was no sequence similarity between promoter regions of IP(3)R3 and IP(3)R2, another ubiquitous gene, except for GC-boxes. By using a series of 5'-truncation versions and a transient luciferase assay, we detected multiple common and cell-type-dependent regulatory regions within the distal promoter sequence downstream from -4.0 kb that function positively or negatively. The IP(3)R3 gene was highly transcribed in the kidney, spleen, heart, and skeletal muscle, and this tissue distribution pattern was nearly complementary to that of IP(3)R2. We found that IP(3)R3 gene expression was repressed in retinoic acid-treated and neural differentiated P19 mouse embryonic carcinoma cells.

Detection and partial structure elucidation of basic taxoids from Taxus wallichiana by electrospray ionization tandem mass spectrometry.

A sensitive method for the detection and characterization of basic taxoids from the ethyl acetate extract of Taxus wallichiana has been described. A combined analysis of the fragmentation spectra of 3 purified standard basic taxoids and the substructure analysis of 139 previously reported taxoids provided information on typical primary and secondary product ions that are generated by CID mass spectrometry of basic taxoids. Precursor-scan analysis of selected product ions allowed for the detection of 57 basic taxoids from the ethyl acetate extract of T. wallichiana, 45 of which have not been reported. The method describe in this paper provides a fast method for the "dereplication" of natural products. The mass spectrometric data derived by this method was sufficient for the partial structure elucidation of novel basic taxoids. The method presented in this paper can be easily adapted into a high-throughput screening protocol for the identification and characterization of bioactive natural products.

Molecular cloning and characterization of neural activity-related RING finger protein (NARF): a new member of the RBCC family is a candidate for the partner of myosin V.

Activity-dependent synaptic plasticity has been thought to be a cellular basis of memory and learning. The late phase of long-term potentiation (L-LTP), distinct from the early phase, lasts for up to 6 h and requires de novo synthesis of mRNA and protein. Many LTP-related genes are enhanced in the hippocampus during pentyrenetetrazol (PTZ)- and kainate (KA)-mediated neural activation. In this study, mice were administered intraperitoneal injections of PTZ 10 times, once every 48 h, and showed an increase in seizure indexes. Genes related to plasticity were efficiently induced in the mouse hippocampus. We used a PCR-based cDNA subtraction method to isolate genes that are expressed in the hippocampus of repeatedly PTZ-treated mice. One of these genes, neural activity-related RING finger protein (NARF), encodes a new protein containing a RING finger, B-box zinc finger, coiled-coil (RBCC domain) and beta-propeller (NHL) domain, and is predominantly expressed in the brain, especially in the hippocampus. In addition, KA up-regulated the expression of NARF mRNA in the hippocampus. This increase correlated with the activity of the NMDA receptor. By analysis using GFP-fused NARF, the protein was found to localize in the cytoplasm. Enhanced green fluorescent protein-fused NARF was also localized in the neurites and growth cones in neuronal differentiated P19 cells. The C-terminal beta-propeller domain of NARF interacts with myosin V, which is one of the most abundant myosin isoforms in neurons. The NARF protein increases in hippocampal and cerebellar neurons after PTZ-induced seizure. These observations indicated that NARF expression is enhanced by seizure-related neural activities, and NARF may contribute to the alteration of neural cellular mechanisms along with myosin V.

Increased oxidative DNA damage in mammary tumor cells by continuous epidermal growth factor stimulation.

BACKGROUND: Growth factors can enhance the malignant potential of tumor cells. To examine the relationship between growth factors and tumor progression, we previously established a weakly malignant cell line, ER-1. We found that a 24-hour exposure of ER-1 cells to epidermal growth factor (EGF) induced malignant properties (tumor progression) that were reversible but that, after a 1-month exposure, these changes were irreversible. In this study, we investigated the irreversible changes induced in ER-1 cells by a 1-month exposure to EGF and the possible involvement of oxidative stress. METHODS: ER-1 cells were treated with EGF (100 ng/mL) for 1 month in the presence or absence of an antioxidant, N-acetylcysteine or selenium, and compared with untreated control ER-1 cells. We assessed tumor progression by measuring intracellular peroxide levels, 8-hydroxydeoxyguanosine (a marker for oxidative DNA damage) levels, in vitro invasiveness, and in vivo tumorigenicity and metastatic ability. All statistical tests are two-sided. RESULTS: After ER-1 cells were treated for 1 month with EGF, levels of intracellular peroxide and 8-hydroxyguanosine in the DNA of treated cells were higher than those in the DNA of control cells, and treated ER-1 cells were more tumorigenic and metastatic in vivo and more invasive in vitro than untreated control cells (all P<.001). Levels of 8-hydroxyguanosine in DNA increased as the length of the EGF treatment increased (P<.001). However, when N-acetylcysteine or selenium was added with EGF for 1 month, levels of intracellular peroxide and 8-hydroxyguanosine in DNA were comparable to those in control cells (r =.795). Both tumorigenicity (P =.008) and metastatic ability (P<.001) decreased after addition of N-acetylcysteine or selenium. CONCLUSION: The irreversible changes caused by continuous EGF stimulation of ER-1 cells result from increased oxidative damage in the DNA, which generates tumor cells with more malignant characteristics.

Enhancement of hepatocarcinogenesis initiated with diethylnitrosamine or N-nitrosobis(2-hydroxypropyl)amine by a choline-deficient, L-amino acid-defined diet administered prior to the carcinogen exposure in rats.

Effects of pre-administration of a choline-deficient, L-amino acid-defined (CDAA) diet on hepatocarcinogenesis initiated with diethylnitrosamine (DEN) or N-nitrosobis(2-hydroxypropyl)amine (BHP) in rats were investigated. A pre-administrating period was set as 1 week, because CDAA diet induces liver injuries by this time-point. In a time-course study, male Fischer 344 rats, 6 weeks old, received a 1-week pre-administration of choline-supplemented, L-amino acid-defined (CSAA) or CDAA diet, DEN at a dose of 100 mg/kg body weight by a single intraperitoneal injection, then CSAA or CDAA diet for up to 8 weeks, and were sacrificed 4, 6 and 8 weeks after DEN. CDAA diet administered only after DEN significantly increased the numbers of glutathione S-transferase placental form (GST-P)-positive lesions 4, 6 and 8 weeks after DEN and their sizes 6 and 8 weeks after DEN. CDAA diet administered both before and after DEN similarly increased the numbers and sizes of GST-P-positive lesions, but with a significantly greater degree than obtained by the diet administered only after DEN. In a dose response study, rats received vechicle or DEN, at a dose of 0.001, 0.01, 0.1, 1, 10, 20, 50, 100 or 200 mg/kg body weight, 1 week after the commencement of CSAA or CDAA diet, and sacrificed 8 weeks after vehicle or DEN. The significant increases of the numbers of GST-P-positive lesions were obtained after 50-200 mg/kg body weight of DEN under the CSAA diet administration, whereas those were detected after 10-200 mg/kg under CDAA diet administration. Sizes became significantly larger with only 200 mg/kg body weight of DEN in the CSAA case but with 50-200 mg/kg in the CDAA case. Male Wistar rats received a 1-week pre-administration of CSAA or CDAA diet, vehicle or BHP, at a dose of 600 or 1200 mg/kg body weight, by a single intraperitoneal injection, then CSAA or CDAA diet for 8 weeks, and were then sacrificed. The numbers of GST-P-positive lesions demonstrated significant increment with 1200 mg/kg body weight of BHP by CDAA diet administered only after BHP and, to a significantly greater degree, by the diet administered both before and after BHP. While CDAA diet administered only after BHP did not alter the sizes of GST-P-positive lesions, the diet administered both before and after 600 and 1200 mg/kg body weight of BHP significantly increased the sizes of the lesions. These results indicate that the pre- plus post-administration of CDAA diet enhances hepatocarcinogenesis initiated with DEN or BHP, more than the post-administration only, thus providing a sensitive model to detect weak liver carcinogenic potency of environmental chemicals.

Characteristics of polyarthritis in rabbits by hyperimmunization with attenuated Enterococcus faecalis.

To produce polyarthritis and rheumatoid factor like substance (RFLS), rabbits were hyperimmunized intravenously with 0.02% thimelosal (TMS)-treated Enterococcus faecalis (E. faecalis) as a persistent bacterial flora. Swelling of knee joints occurred at a rate of 41% (27/66), and of shoulder joints at a rate of 25% (17/66) while that of elbow joints occurred at a rate of 4.5% (3/66). On culturing of knee joint fluids, no colonies appeared while 2/4 fluid specimens from the shoulder joints gave positive colonies for 78 days after the first immunization; thereafter, no colonies appeared. On histological examination, in early stages, acute inflammatory reactions with degenerative changes of synovial tissue was observed. In later stages, chronic inflammatory changes, proliferation of synovial cells with pannus formation, destruction of articular cartilage and subchondral bone were observed. RFLS titer showed bi-phasic peaks at 11 days and 41 days after the first immunization. A high incidence of polyarthritis, particularly knee joints, occurred. Thus, hyperimmunization with attenuated E. faecalis as a normal intestinal flora may provide an animal model of chronic polyarthritis.

Inhibitory effects of combined administration of antibiotics and anti-inflammatory drugs on lung tumor development initiated by N-nitrosobis(2-hydroxypropyl)amine in rats.

The effects of antibiotics and anti-inflammatory drugs on the promotion stage of lung carcinogenesis initiated with N-nitrosobis(2-hydroxypropyl)amine (BHP) in rats were investigated in two experiments with a similar protocol. In experiment 1, rats received tap water containing 2000 p.p.m. BHP for 12 weeks followed by basal diet or basal diet containing 0.02% erythromycin (EM), 0. 04% ampicillin (ABPC), 1.5% sho-saiko-to, 0.02% EM plus 1.5% sho-saiko-to or 0.04% ABPC plus 1.5% sho-saiko-to for 8 weeks after BHP administration. The development of adenocarcinomas (AC), squamous cell carcinomas (SqC) and adenosquamous carcinomas (ASqC) was completely inhibited in rats given ABPC plus sho-saiko-to and the numbers of lung lesions including alveolar hyperplasias, adenomas and carcinomas were decreased in rats given EM plus sho-saiko-to or ABPC plus sho-saiko-to. Neutrophil and macrophage infiltration into alveolar spaces of the lung were also markedly suppressed. In experiment 2, rats received BHP in the same manner as in experiment 1 and basal diet or basal diet containing 0.04% ABPC, 0.006% piroxicam, 0.04% ABPC plus 0.006% piroxicam and 0.04% ABPC plus 0.75% ougon for 8 weeks. The incidence and number of carcinomas, including ACs, SqCs and ASqCs were decreased in rats given ABPC plus piroxicam or ABPC plus ougon. Bacteria, mainly Escherichia coli, were detected in broncho-alveolar lavage of rats receiving BHP. The results suggest that chronic inflammation might be involved in the progression of lung carcinogenesis by BHP in rats and its suppression may therefore be useful as a chemopreventive strategy in lung cancer clinics.

Epigallocatechin gallate and gallocatechin gallate in green tea catechins inhibit extracellular release of Vero toxin from enterohemorrhagic Escherichia coli O157:H7.

We studied the effects of six catechin derivatives (catechin, epigallocatechin, epicatechin, epicatechin gallate, epigallocatechin gallate (EGCg) and gallocatechin gallate (GCg)) in green tea on the production and extracellular release of Vero toxins (VTs) from enterohemorrhagic Escherichia coli (EHEC) cultured at 37 degrees C for 24 h. EGCg and GCg in the culture medium markedly inhibited extracellular VTs release from EHEC cells into the culture supernatant fluid at concentrations of 0.05 mg/ml or higher, as estimated by both the reversed passive latex agglutination assay and cytotoxic assay using Vero cells. Production and extracellular release of maltose binding protein, a periplasmic protein, into the culture supernatant were also inhibited by EGCg and GCg, indicating that their inhibitory effect on release from periplasm into the outer milieu is not specific to VTs, but general to the proteins accumulated in EHEC periplasm.

Delay in administration of CDDP until completion of AGM-1470 treatment enhances antimetastatic and antitumor effects.

The efficacy of cis-diammine dichloroplatinum (CDDP) therapy in combination with continuous administration of angiogenesis inhibitor o-(chloroacetyl-carbamoyl) fumagillol (AGM-1470) was evaluated experimentally using a transplantable rat osteosarcoma line previously established in our laboratory. AGM-1470 (2.5 mg/kg body weight/week) was administered by Alzet osmotic pumps for 2 weeks starting from 7 days after tumor inplantation and CDDP (1.25 mg/kg) was given on days 21 and 24. The number of lung metastatic nodules was counted and the wet weights of the primary tumors were measured 5 weeks after tumor inplantation. Values with administration of CDDP 3 days after discontinuation of AGM-1470 were significantly lower than when the two agents were coadministered (P < 0.05). This animal model should facilitate optimization of the timing of combination therapy.

Telomerase activity correlates with growth of transplantable osteosarcomas in rats treated with cis-diammine dichloroplatinum or the angiogenesis inhibitor AGM-1470.

To determine the role of telomerase activity in the growth of tumors in rats undergoing chemotherapy, a comparison of the volumes of telomerase-positive transplantable osteosarcomas was made in rats treated with the antineoplastic agent cis-diammine dichloroplatinum (CDDP) or the angiogenesis inhibitor O-(chloroacetylcarbamoyl)fumagillol (AGM-1470). Male F344 rats, 8 weeks old, received transplants of macroscopic lung metastatic nodules into the subcutaneous back space and treatment was started on day 14 thereafter. CDDP was injected i.v. at doses of 0, 0.625, 1.25 and 2.5 mg/kg body weight (b.w.) and AGM-1470 was administered at total doses of 0, 2.5, 5 and 10 mg/kg b.w. over 2 weeks by osmotic pumps, also implanted into the subcutaneous back space, but remote from the transplanted tumors. On day 28, all animals were killed for measurement of transplanted tumor size and determination of telomerase activities by telomeric repeat amplification protocol (TRAP) assay. The results showed telomerase activity to be highly correlated with the treated/non-treated (T/C) tumor size ratio (r = 0.96, P < 0.0001). In a second experiment, CDDP at 2.5 mg/kg b.w. and AGM-1470 at 10 mg/kg b.w., these being the most effective doses, were given as in the first experiment, and animals were serially killed on days 14, 21, 28, 35 and 42. Tumors in rats treated with CDDP and AGM-1470 showed 18.2% and 20.5% of the control telomerase activity on days 35 and 21, respectively, when tumor growth was inhibited. However, on day 42, the activities increased to 46.5% and 92.5%, this correlating with re-growth (r = 0.73, P < 0.0001). These results suggest that decline of telomerase activity may be involved in tumor growth retardation induced by chemotherapeutic agents. This possibility clearly warrants further mechanistic studies.

Prevention by inhibitors of arachidonic acid cascade of liver carcinogenesis, cirrhosis and oxidative DNA damage caused by a choline-deficient, L-amino acid-defined diet in rats.

Effects of inhibitors of arachidonic acid (AA) cascade on the development of fatty liver, cirrhosis, glutathione S-transferase placental form (GST-P)-positive preneoplastic nodules, neoplastic nodules and generation of 8-hydroxydeoxyguanosine (8-OHdG), caused by a choline-deficient, L-amino acid-defined (CDAA) diet, were examined in Fischer 344 male rats by feeding CDAA diet supplemented with the inhibitors for 12 and 30 weeks. None of the inhibitors affected fatty liver. Among cyclooxygenase (COX) inhibitors, an irreversibly acting acetylsalicylic acid and a long-acting piroxicam, and to a much lesser extent the short-acting ibuprofen but not indomethacin, inhibited the development of cirrhosis, GST-P-positive and neoplastic nodules and generation of 8-OHdG. A phospholipase A2 inhibitor p-bromophenacylbromide (BPB) also exerted similar but lesser extent of inhibitory effects. Lipoxygenase inhibitors quercetin and nordihydroguiaretic acid inhibited GST-P-positive nodules but not cirrhosis or 8-OHdG. Present results suggest that perturbed AA cascade, particularly augmented COX pathway, might play key roles in the causation of liver lesions in the CDAA diet model.

Quantitative analysis of Aconitum alkaloids in the urine and serum of a male attempting suicide by oral intake of aconite extract.

A method for the quantitation of diesterditerpene-type Aconitum alkaloids and their hydrolysis products by gas chromatography-selected ion monitoring was applied to a clinical case study. A 45-year-old male attempted suicide by oral intake of Aconitum alkaloids, which are highly intoxicant extracts of Aconitum tubers. It was estimated that he had ingested approximately 11 mg of diesterditerpene-type alkaloids but was saved by intensive gastric irrigation. Mesaconitine, aconitine, hypaconitine, and their hydrolysis products were detected in the serum on the first day only. On the other hand, some alkaloids were still detectable in the urine even six days after intoxication. Aconitum alkaloids are biotransformed, and their hydrolysis products are excreted time-dependently to the urine. The urine was a useful material to identify the toxicants in the case of aconite intoxication.