Reversal of LRP-associated drug resistance in colon carcinoma SW-620 cells

Resistance to multiple drugs is mediated by lung resistance-related protein (LRP) as well as P-glycoprotein (P-gp) and multidrug resistance protein (MRP). The levels of expression of LRP mRNA and LRP in a human colon carcinoma cell line, SW-620, were increased by the differentiation-inducing agent, sodium butyrate (NaB). Treatment of SW-620 cells with NaB for 2 weeks conferred resistance to adriamycin (ADM) and VP-16. The resistance was almost completely reversed by PAK-104P, a pyridine analog, but not by cepharanthine. ADM accumulated mainly in the nuclei of SW-620 cells not treated with NaB and in the cytoplasm of SW-620 cells treated with NaB. When the NaB-treated SW-620 cells were incubated with ADM in the presence of PAK-104P, the accumulation of ADM in nuclei was substantially increased. Isolated nuclei from untreated cells accumulated more ADM than nuclei from NaB-treated cells. Efflux of ADM from the nuclei isolated from NaB-treated cells was enhanced. PAK-104P and an antibody against LRP increased the accumulation of ADM in the isolated nuclei from NaB-treated cells, and inhibited the enhanced efflux of ADM from the nuclei. These findings suggest that at least in part, PAK-104P reverses LRP-mediated drug resistance by inhibiting the efflux of ADM from nuclei. PAK-104P may be useful for reversing MDR in tumors that overexpress LRP.

Effect of polaprezinc on impaired healing of chronic gastric ulcers in adjuvant-induced arthritic rats--role of insulin-like growth factors (IGF)-1

Polaprezinc, N-(3-aminopropionyl)-L-histidinatozinc, has been shown to stimulate the production of insulin-like growth factor-1 (IGF-1) in mesenchymal cells, the polypeptide playing a role in the gastric epithelial wound repair. The present study was performed to examine the effect of polaprezinc on the impaired healing of chronic gastric ulcers in adjuvant-induced arthritic rats, in relation to IGF-1. Arthritis was induced in male Dark Agouti (DA) rats by a single injection of Freund's complete adjuvant (FCA), and the gastric ulcers were induced by thermal cauterization (70 degrees C for 30 sec) 7 days after FCA injection. Omeprazole (30 mg/kg) was administered p.o. once daily, while recombinant human IGF-1 (rhIGF-1) (30 micrograms/kg, s.c.) or polaprezinc (3-10 mg/kg, p.o.) was administered twice daily, starting from 3 days after ulceration for 14 days. The healing of gastric ulcers was significantly delayed in arthritic rats as compared to normal rats on day 10 and 17 following ulceration. The expression of IGF-1 mRNA was markedly increased in the ulcerated mucosa, but this response was apparently attenuated in arthritic rats. Repeated administration of polaprezinc accelerated the healing of gastric ulcers in both normal and arthritic rats, in a dose-dependent manner, and this effect was more pronounced in arthritic rats. Likewise, treatment with omeprazole also significantly promoted the healing of gastric ulcers in both normal and arthritic rats. On the other hand, rhIGF-1 significantly promoted the gastric ulcer healing in arthritic rats without any effect on that in normal rats. These results suggest that the impaired healing of chronic gastric ulcers in arthritic rats is, at least partly, accounted for by less expression of IGF-1, and the polaprezinc improves the delayed healing of gastric ulcers in arthritic rats, probably through an increase in IGF-1 production.

MRI and arthroscopic findings in the temporomandibular joint after mandibulectomy including the unilateral condyle. Report of two cases

In this report, the MRI and arthroscopic findings in the temporomandibular joint (TMJ) of two patients who underwent partial mandibulectomy including the condyle are presented. The disc and superior joint compartment of the affected TMJs were preserved in both patients. MRI of the affected TMJs without condyle demonstrated that the intermediate zone of the discs was located anteriorly to the summit of the articular eminence. Joint effusion was detected in the superior joint compartment of one patient. Fibrous adhesions were observed arthroscopically in the superior joint compartment of both affected TMJs. In contrast, no specific findings were demonstrated in the contralateral TMJs connected with the residual mandibular fragment.

Polaprezinc exerts a salutary effect on impaired healing of acute gastric lesions in diabetic rats

We examined the influence of diabetes mellitus (DM) on the healing of HCl-induced gastric lesions and the healing promoting effect of polaprezinc [N-(3-aminopropionyl)-L-histidinato zinc] on these lesions. Studies were performed on rats injected intraperitoneally with streptozotocin (STZ, 70 mg/kg) five weeks prior to experiments. Diabetic rats had blood glucose levels (BGLs) higher than 350 mg/100 ml. Randomly chosen animals were treated subcutaneously with insulin (4 IU/day/rat) starting 1 week after STZ. Animals were given 1 ml of 0.6 N HCl by oral gavage (per os) following 18 hr of fasting; they were fed normally from 1 hr later and killed at various time points after HCl administration. Polaprezinc (3-30 mg/kg) or its components ZnSO4/7H2O and L-carnosine were given orally, twice daily for four days following HCl treatment. Gastric lesions induced by HCl healed macroscopically to quiescence within 10 days. DM and insulin did not affect the development of HCl-invoked gastric lesions, but the healing of such lesions was markedly impaired in animals with DM. Daily administration of insulin returned high BGLs to significantly lower ranges (190-208 mg/100 ml) and markedly antagonized the healing impairment. Polaprezinc (>10 mg/kg) significantly reversed the delay observed in diabetic rats without any notable effects on BGLs or acid secretion. Similar trends were observed with ZnSO4/7H2O or a mixture of ZnSO4/7H2O and L-carnosine, but not by L-carnosine alone. The mucosal expression of insulin-like growth factor-1 (IGF-I) mRNA was significantly lower in diabetic rats, a dysregulation partially corrected by insulin and polaprezinc. In addition, the delayed healing in diabetic rats was also significantly promoted by the repeated subcutaneous administration of rhIGF-I (>10 microg/kg, twice daily) without any notable effect on BGLs or acid secretion. These results suggest that DM exerted a deleterious influence on the healing of acute gastric lesions in both insulin- and zinc-sensitive manner. The salutary effects of polaprezinc on the impaired healing of gastric lesion in STZ-diabetic animals may at least be partly explained by enhancement of mucosal IGF-I mRNA expression in the stomach.

Complications of temporomandibular joint arthroscopy: a retrospective analysis of 301 lysis and lavage procedures performed using the triangulation technique

PURPOSE

This study evaluated the complications of temporomandibular joint (TMJ) arthroscopic lysis and lavage performed using the triangulation technique.

PATIENTS AND METHODS

The 202 consecutive patients (301 joints) who underwent arthroscopic lysis and lavage between 1992 and 1995 were retrospectively surveyed. The preoperative diagnosis of all patients was anterior disc displacement without reduction.

RESULTS

Complications were observed in 31 (10.3%) of 301 cases of arthroscopic lysis and lavage. Of these, otologic complications were found in 26 cases (8.6%): blood clots in the external auditory canal in 9; laceration of external auditory canal in 7; partial hearing loss in 5; ear fullness in 2; vertigo in 1; and perforation of tympanic membrane with laceration of external auditory canal in 1. Neurologic injuries were found in 5 cases (1.7%): fifth cranial nerve injuries in 3; and seventh cranial nerve injuries in 2. No other complications were observed.

CONCLUSIONS

A high level of understanding of the regional anatomy helps reduce the complications associated with arthroscopic lysis and lavage in the TMJ.

Magnetic resonance imaging findings and clinical symptoms in the temporomandibular joint in patients with mandibular continuity defects

PURPOSE

This study explored the morphologic changes and clinical symptoms related to the temporomandibular joint (TMJ) associated with long-term lack of mandibular continuity.

PATIENTS AND METHODS

The subjects were 20 patients (40 TMJs) who underwent mandibulectomy including the condyle or segmental mandibulectomy without mandibular reconstruction more than 6 months previous to the study. The 40 TMJs were classified into the following 3 groups: group I: TMJs with a major mandibular fragment including the mandibular body (n = 21), group II: TMJs with a minor mandibular fragment including only the condylar process or the mandibular ramus (n = 10), and group III: TMJs without a condyle (n = 9). All TMJs were examined with respect to disc position, condylar position, bony changes, and appearance of joint effusion on magnetic resonance imaging, as well as for the presence of joint or muscle pain and joint noise.

RESULTS

The rate of anterior disc displacement was 28.6% in group I, 10.0% in group II, and 100% in group III. All condyles in group I were located in the glenoid fossa. Seven of 10 condyles in group II were dislocated anteriorly out of the glenoid fossa. However, these condyles were situated in the intermediate zone of the disc. Osteoarthritic changes was found in 1 joint in group II. Joint effusion was not observed in group I. However, joint effusion was detected in the posterior region of the upper joint compartment in 7 of 10 TMJs in group H and in 8 of 9 TMJs in group III. In group II, the 7 TMJs with joint effusion were the same joints with anteriorly dislocated condyles. Clinical symptoms of TMJ pain, TMJ noise, or muscular pain were not found in any patients.

CONCLUSIONS

Partial mandibulectomy does not affect the relationship between the disc and the condyle or the bony condition of the TMJ. The disc without a condyle will become anteriorly displaced with time. The condyle not connected to the mandibular body often dislocates anteriorly out of the glenoid fossa, while retaining a normal relationship with the disc. Joint effusion, which is detected in nonfunctional TMJs, is not associated with an inflammatory reaction in the joint compartment.

Rat CXC chemokine GRO/CINC-1 paradoxically stimulates the growth of gastric epithelial cells

BACKGROUND

CXC chemokines such as interleukin (IL)-8 are neutrophil chemoattractants, the levels of which increase in Helicobacter pylori-infected gastric mucosa. Many investigators have focused on the chemotactic aspects of IL-8: however, CXC chemokines are also reported to have angiogenic activity and to serve as remodelling factors. Rat GRO/CINC-1 is a rodent counterpart of human GROalpha, a member of the family of CXC chemokines. Gastric mucosa infected with H. pylori is in a state of hyperproliferation, with increases in the amounts of growth factors such as hepatocyte growth factor (HGF).

AIM

To investigate whether rat GRO/CINC-1 had growth-stimulating activity for gastric epithelial cells.

METHODS

The rat gastric epithelial cell line RGM-1 was incubated in serum-free medium for 12 h to adjust the cell cycle to the G0 phase, and GRO/CINC-1 was then added for 24 h. The total cell number was determined by fluorogenic analysis after propidium iodide staining, and cell proliferation was assessed by measuring 5-bromo-2'-deoxyuridine (BrdU) incorporation. The activity of p42/p44 mitogen-activated protein kinase (MAPK) was measured 5-20 min after the start of GRO/CINC-1 exposure.

RESULTS

Cultures treated with GRO/CINC-1 showed a significant increase in cell number and BrdU incorporation in a concentration-dependent fashion. The MAPK activity increased within 5 min after GRO/CINC-1 application and returned to the control level at 20 min.

CONCLUSION

The growth-stimulatory effect of GRO/CINC-1 on rat gastric epithelial cells suggests a dual function of this chemokine: proinflammatory action and induction of epithelial proliferation.

[Epidemiological analysis of Shiga toxin-producing Escherichia coli O157 isolates from familial infection]

A total of 201 Shiga toxin-producing Escherichia coli (STEC) O157:H7 isolates from 22 epidemiologically unrelated familial infections in Osaka were analyzed by various epidemiological markers, such as Shiga toxin (STx) typing, antimicrobial resistant patterns, colicine typing, plasmid profiles and pulsed-field gel electrophoresis (PFGE) typing. There were two cases where different type strains were detected in a family (family No. 21 and 22). In the family No. 21, three different strains were isolated from a 5-year-old male infant; one identical with that from his mother, and the others different in 4 markers except STx type. In the family No. 22, two kinds of strain were detected in a 48-year-old father; one identical with those from other members of the family, and the other different in STx, plasmid profile and PFGE types. These facts showed the possibility of a simultaneous double infection from the common sources of infectious factors or a successive reinfection with different types of the agents. Identical marker strains were detected from 8 out of 12 familial infection cases from July to September. Although infectious sources of these cases are not yet clearly identified, these results of epidemiological markers analysis indicate a probable circulation of the common contaminated foodstuffs. A combined use of phenotypic and genotypic tests were shown to be useful for the epidemiological analysis. Further, it seemed necessary to examine epidemiological markers of more than one strain in familial infection or identical facilities generation cases. And also a collective analysis of the relating factors such as biological markers of the causative agents, the list of eaten foodstuffs, and successive outbreaks of the patients was thought most important.

Polaprezinc, a gastroprotective agent: attenuation of monochloramine-evoked gastric DNA fragmentation

We previously reported that NH2Cl induced extensive DNA fragmentation in gastric cells. Polaprezinc, a zinc-carnosine chelate compound, is reported to be a potent antioxidant in gastric mucosa. The present study was designed to examine whether polaprezinc could attenuate the NH3Cl-induced DNA damage. Gastric cell lines, MKN45, were exposed to NH2Cl in Ca(2+)-containing Hanks' balanced salt solution. DNA fragmentation was evaluated by photometric enzyme immunoassay for in vitro determination of cytoplasmic mono- and oligonucleosomes. Polaprezinc, L-carnosine, and zinc sulfate (ZnSO4) were added to the cell incubation medium to evaluate the inhibitory effect on the formation of cytoplasmic mono- and oligonucleosomes. Separately, the bleaching level of beta-carotene with the addition of each test solution was evaluated to confirm the inhibitory effect against hypochlorous acid. Polaprezinc or L-carnosine, but not ZnSO4, at a concentration of 0.001 mM, significantly attenuated the increased levels of cytoplasmic mono- and oligonucleosomes evoked by 0.001 mM NH2Cl. Polaprezinc and L-carnosine, but not ZnSO4, also inhibited NH2Cl-induced beta-carotene bleaching in the cell-free system. In conclusion, polaprezinc, especially its subportion L-carnosine, inhibited NH2Cl-evoked gastric epithelial DNA fragmentation, suggesting a role for this agent in preventing the progression of gastric epithelial injury induced by NH2Cl.

Histological evaluation of autogenous iliac particulate cancellous bone and marrow grafted to alveolar clefts--a preliminary report of five young adult cases

OBJECTIVE

We histologically evaluated iliac particulate cancellous bone and marrow (PCBM) grafted to alveolar clefts in five young adults with cleft lip and palate.

PATIENTS AND METHODS

Five young adults with cleft lip and palate underwent secondary alveolar bone grafting. The mean age of the patients was 21.2 years (range = 17 to 27 years). Bone specimens were taken from the graft site 5 to 10 months after the surgery simultaneously with implant fixture placement (two cases), vestibuloplasty (two cases), and rebone grafting (one case). These five bone specimens were prepared and stained with hematoxylin and eosin and examined microscopically.

RESULT

One specimen, taken 5 months after surgery, showed immature trabecular bone partially lined by osteoblasts. The remaining four specimens showed well-mineralized trabeculae and fatty change in the marrow space.

CONCLUSION

In young adult cases, PCBM remodeled after grafting and became mature bone about 5 to 6 months after the surgery.

Ethanol intake preceding Helicobacter pylori inoculation promotes gastric mucosal inflammation in Mongolian gerbils

BACKGROUND

Mongolian gerbils have been reported to be a suitable model for Helicobacter pylori-associated gastric mucosal injury, including gastric cancer. Although ethanol is known to be one of the harmful substances in the gastric mucosa, the relationship between ethanol and H. pylori infection remains unknown. The aim of the present study is to investigate the effect of ethanol treatment prior to H. pylori inoculation on associated gastric mucosal injury.

METHODS

Male Mongolian gerbils were used for the study. Helicobacter pylori was orally inoculated after 15 h fasting (Hp group). Thirty minutes prior to H. pylori inoculation, a group of gerbils was orally treated with 40% ethanol (20 mL/kg; E + Hp group). Another group of animals was treated either with H. pylori culture media alone (controls) or with 40% ethanol plus culture media (E group). Gerbils were killed 2, 4 or 12 weeks after H. pylori inoculation. Helicobacter pylori infection was confirmed by both histological examination and serological tests. Mucosal damage was evaluated histologically according to the modified Sydney system.

RESULTS

Although in the controls and E group no significant change to the gastric mucose was observed, persistent H. pylori infection was seen in the mucosa and mucosal leucocyte infiltration and severe epithelial damage was observed in the Hp and E + Hp groups after 4 weeks. The histological scores for polymorphonuclear cell infiltration and myeloperoxidase activity were higher in the E + Hp group at 4 weeks than in the Hp group (P < 0.05).

CONCLUSIONS

Ethanol intake preceding H. pylori inoculation could promote the progression of gastric mucosal inflammation in Mongolian gerbils.

Effect of polaprezinc (N-(3-aminopropionyl)-L-histidinato zinc), a novel antiulcer agent containing zinc, on cellular proliferation: role of insulin-like growth factor I

The effect of polaprezinc (N-(3-aminopropionyl)-L-histidinato zinc), a novel antiulcer drug containing zinc, on cellular proliferation was studied using cultured cells. In human umbilical vein endothelial cells (HUVEC) or human foreskin fibroblast cells, bromodeoxyuridine (BrdU) uptake and the number of cells were increased by polaprezinc under low serum conditions, but polaprezinc had no effect on guinea pig gastric mucosal epithelial cells. In addition, L-carnosine (a component of polaprezinc) had no effect on cultured HUVEC, while zinc sulfate, a representative zinc compound, increased BrdU uptake by about 2-fold at 10(-9) M. However, the action of zinc sulfate was weaker than that of polaprezinc. The insulin-like growth factor I (IGF-I) mRNA level was increased in HUVEC by polaprezinc at 10(-9) M approximately 3 x 10(-8) M concentrations, causing stimulation of BrdU uptake. When an anti-IGF-I antibody was added to cultures, the effects of polaprezinc on BrdU uptake was suppressed. These results suggest that although polaprezinc, a novel antiulcer agent, does not have proliferative effects on epithelial cells, it does promote the proliferation of non-parenchymal cells, and IGF-I is involved in this action.

An object-modeling method for hospital information systems

Our goal is to increase the software productivity of hospital information systems (HISs) by applying object-oriented technologies. We propose a new object-modeling method for HISs that combines three general methods--an object modeling technique (OMT), class responsibilities collaboration (CRC) cards, and a use-case approach--to extract objects effectively. Our method also takes HIS functionality characteristics such as history and patient-staff linking into consideration to increase the reusability of objects. To test this method, we applied it to several HISs such as a drug-history system, a nursing-support system and an electronic patient record (EPR). We found that the software productivity of the drug-history system was more than doubled by using the combined method. Also, more than 40% of the logic classes could be reused in the nursing-support system and EPR. These findings confirmed that the proposed method can significantly increase the software productivity of HISs.

Intracerebroventricular injection of a nitric oxide donor attenuates Fos expression in the paraventricular and supraoptic nuclei of lactating rats

The exact nature of how nitric oxide (NO) acts in the regulation of milk ejection during lactation is not clearly understood at the moment. In this study, we have examined the effect of drugs which spontaneously release NO (sodium nitroprusside, SNP) or inhibit the NO synthase (NOS) enzyme (Nomega-nitro-L-arginine, L-NA) on the activity of some hypothalamic and functionally associated nuclei using Fos expression as an index of neuronal activation. Lactating rats received intracerebroventricular injection of SNP, l-NA or vehicle (saline) just before they were reunited with their pups after a 12-h period of separation and allowed to suckle for 2 h. The difference in the total pup body weight before and after the period of suckling was used as a functional end-point of milk transfer. Central injection of SNP in conscious rats significantly inhibited Fos expression in the paraventricular nucleus (PVN), supraoptic nucleus (SON), periventricular and preoptic nuclei and also decreased pup body weight compared with saline- or l-NA-injected rats. Urethane-anesthetized animals, compared with their conscious counterparts, showed increased Fos expression in the PVN and SON. However, Fos expression in the PVN of the anesthetized animals was attenuated by l-NA injection compared with SNP and saline injection. Taken together with an earlier finding that SNP disrupts the milk ejection burst of oxytocinergic neurons, these observations suggest that NO may act within the neuron(s) possibly to alter the mechanism(s) regulating the periodic neuronal burst activity during lactation.

ATP-Dependent efflux of CPT-11 and SN-38 by the multidrug resistance protein (MRP) and its inhibition by PAK-104P

Non-P-glycoprotein-mediated multidrug-resistant C-A120 cells that overexpressed multidrug resistance protein (MRP) were 10.8- and 29. 6-fold more resistant to 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin (CPT-11) and SN-38, respectively, than parental KB-3-1 cells. To see whether MRP is involved in CPT-11 and SN-38 resistance, MRP cDNA was transfected into KB-3-1 cells. The transfectant, KB/MRP, which overexpressed MRP, was resistant to both CPT-11 and SN-38. 2-[4-Diphenylmethyl)-1-piperazinyl]ethyl-5-(trans-4,6-dimethyl-1,3 , 2-dioxaphosphorinan-2-yl)-2, 6-dimethyl-4-(3-nitrophenyl)-3-pyridinecarboxylate P-oxide (PAK-104P) and MK571, which reversed drug resistance in MRP overexpressing multidrug-resistant cells, significantly increased the sensitivity of C-A120 and KB/MRP cells, but not of KB-3-1 cells, to CPT-11 and SN-38. The accumulation of both CPT-11 and SN-38 in C-A120 and KB/MRP cells was lower than that in KB-3-1 cells. The treatment with 10 microM PAK-104P increased the accumulation of CPT-11 and SN-38 in C-A120 and KB/MRP cells to a level similar to that found in KB-3-1 cells. The ATP-dependent efflux of CPT-11 and SN-38 from C-A120 and KB/MRP cells was inhibited by PAK-104P. DNA topoisomerase I expression, activity, and sensitivity to SN-38 were similar in the three cell lines. Furthermore, the conversion of CPT-11 to SN-38 in KB-3-1 and C-A120 cell lines was similar. These findings suggest that MRP transports CPT-11 and SN-38 and is involved in resistance to CPT-11 and SN-38 and that PAK-104P reverses the resistance to CPT-11 and SN-38 in tumors that overexpress MRP.

Effect of water extracts of Rhizopus delemar on the stimulus coupled responses of neutrophils and their modulation by various protein kinase inhibitors

Human peripheral blood polymorphonuclear leukocytes were preincubated with water extracts from Rhizopus delemar. The water extracts significantly inhibited arachidonic acid induced superoxide generation, whereas enhanced superoxide generation induced by phorbol 12-myristate 13-acetate but not those induced by N-formyl-methionyl-leucyl-phenylalanine. Superoxide generation induced by water extracts was inhibited by staurosporine, an inhibitor of protein kinase C, and was enhanced by genistein, an inhibitor of tyrosine kinase. The water extracts incubated with phorbol 12-myristate 13-acetate markedly increased phosphorylation of serine residue of 28.5 kDa protein with time and the phosphorylation depended on the concentration of the water extracts, whereas the water extracts incubated with arachidonic acid decreased the phosphorylation of serine residue of 38 and 42 kDa proteins. The phosphorylation of 28.5 kDa protein induced by the water extracts was inhibited by staurosporine, an inhibitor of protein kinase C, but was not inhibited by genistein, an inhibitor of tyrosine kinase.

Disappearance of a novel protein component of the 26S proteasome during Xenopus oocyte maturation

We have prepared polyclonal antibodies against Xenopus 20S proteasomes. The antibodies cross-react with several proteins that are common to 20S and 26S proteasomes and with at least two proteins that are unique to 26S proteasomes. The antibodies were used to analyze changes in the components of proteasomes during oocyte maturation and early development of Xenopus laevis. A novel protein with a molecular weight of 48 kDa, p48, was clearly detected in immature oocytes, but was found at very low levels in mature oocytes and ovulated eggs. p48 was reduced to low levels during oocyte maturation, after maturation-promoting factor was activated. The amount of p48 in eggs remained low during early embryonic development, but increased again after the midblastula transition. These results show that at least one component of 26S proteasomes changes during oocyte maturation and early development and suggest that alterations in proteasome function may be important for the regulation of developmental events, such as the rapid cell cycles, of the early embryo.

[Rapid and simple method for the detection of shigatoxins (STxs)]

Enterohemorrhagic Escherichia coli (EHEC) is an emerged bacterial agent as the cause of bloody diarrhea and a leading cause of hemolytic uremic syndrome in children. In our country, serotype O 157:H7 is the predominant pathogen in the EHEC and the most frequently seen in human infections. The clinical disease is not associated with the STx types produced by the infecting strains. Non-O157 serotypes of EHEC also produce STxs, and infections with some non-O157 EHEC are occasionally associated with the illness caused by O157:H7. A rapid and simple enzyme immunoassay method (EIA) for the detection of STxs was established. This method is based on the use of anti-STx1 or anti-STx2 monoclonal antibody-labelled colloidal gold for detective factor and also used each anti-STx antibody for the capture antibody. The supernatant was used as the test sample after centrifugation of bacterial suspension treated with polymixin B (5,000 u/ml). These EIA-tests were specific for all supernatants of EHEC serotypes used, giving positive reactions (more than 1:16-32) by the RPLA method, and permitted the detection of ca. 203-812 pg of STx1 or STx2 in a 130 microliters applied to this test. This method will be an extremely useful tool for the detection of STxs from isolates or bacteria on selective agar-plates.

Helicobacter pylori-associated gastric pro- and antioxidant formation in Mongolian gerbils

Helicobacter pylori colonized gastric mucosa is manifest in a significant neutrophil infiltration with an extensive level of oxyradical formation. Mongolian gerbil is one of the excellent models for H. pylori-infection. The present study was designed to investigate pro- and antioxidant formation in the stomach of H. pylori-positive gerbils. Fourteen male Mongolian gerbils (MGS/Sea) were orally inoculated with H. pylori (ATCC43504) (Hp group) and 15 gerbils were inoculated with the culture media (Control). H. pylori infection was confirmed by the serum anti-H. pylori IgG test. Each gerbil was evaluated 6 or 12 weeks after the inoculation. Neutrophil infiltration was assessed by the tissue MPO activity. Mucosal oxidative stress was evaluated by thiobarbituric acid-reactive substances (TBARS), total glutathione contents, glutathione peroxidase (GSHPx) activity and Cu-, Zn-superoxide dismutase (SOD) activity. In Hp group, the H. pylori was persistently infected until 12 weeks. The level of MPO activity was significantly higher in Hp group at 6 and 12 weeks. Although the levels of TBARS and total glutathione were within the same range as controls at 6 weeks, they were significantly increased at 12 weeks. However, GSHPx activity was significantly increased at 6 weeks, but became the same range with the controls at 12 weeks. SOD activity showed no significant increase in Hp group at 6 and 12 weeks. In conclusion, H. pylori inoculation induced gastric mucosal neutrophil activation and pro-oxidant formation and also increased total glutathione contents, one of the mucosal antioxidants in gerbils.

Paracrine upregulation of VEGF receptor mRNA in endothelial cells by hypoxia-exposed hep G2 cells

Although vascular endothelial growth factor (VEGF) plays a role in the growth of hypervascular tumors, mechanisms for paracrine regulation of its receptor expression on vascular endothelial cells remain unknown. This study aimed to investigate whether VEGF released from hypoxia-exposed Hep G2 cells alters expression of the two distinct receptors, kinase insert domain-containing receptor (KDR) and fms-like tyrosine kinase 1 (flt-1), in human umbilical venous endothelial cells (HUVEC). Hep G2 cells were cultured in 20% or 1% O2 for 16 h to examine induction of VEGF mRNA and its protein expression. Conditioned medium from Hep G2 cells (CM) was applied to HUVEC under normoxic conditions, and expression of mRNA for the VEGF receptors was determined by RT-PCR. In response to the hypoxic challenge, Hep G2 cells upregulated VEGF mRNA and the release of VEGF. Hypoxia-CM preferentially stimulated the mRNA expression of flt-1 but not that of KDR in HUVEC. When the VEGF release from hypoxia-exposed Hep G2 cells was blocked by its antisense oligodeoxynucleotide, the endothelial flt-1 mRNA upregulation elicited by the hypoxia-CM was still maintained. These results suggest that hypoxia-exposed Hep G2 cells not only produce VEGF but also evolve paracrine induction of flt-1 through VEGF-independent mechanisms.