Insulin-like growth factor I plays a role in gastric wound healing: evidence using a zinc derivative, polaprezinc, and an in vitro rabbit wound repair model

BACKGROUND

Although the detailed mechanism is unclear, zinc and its derivative, polaprezinc, have been reported to accelerate gastric ulcer healing in vivo.

AIM

To investigate the detailed cellular mechanism of polaprezinc on gastric epithelial cells and fibroblasts with special attention to insulin-like growth factor I (IGF-I).

METHODS

Isolated rabbit gastric epithelial cells formed a complete monolayer, from which a circular artificial wound with constant size was made. The restoration process was monitored by measuring wound size up to 48 h. Either polaprezinc, IGF-I, fibroblast conditioned medium or neutralized medium conditioned by anti-IGF-I antibody was added at the time of wounding. The expression of mRNA of IGF-I, hepatocyte growth factor (HGF) and transforming growth factor alpha (TGF-alpha) in fibroblasts with or without polaprezinc treatment was tested using reverse transcription polymerase chain reaction (RT-PCR). Gastric epithelial cell proliferation was also examined by bromodeoxyuridine (BrdU) staining.

RESULTS

IGF-I and fibroblast conditioned medium treatment accelerated gastric epithelial restoration which included cell migration and proliferation. However, polaprezinc and neutralized conditioned medium treatment did not accelerate epithelial repair. RT-PCR for growth factor mRNA revealed the IGF-I mRNA expression in fibroblasts was increased after treatment with polaprezinc.

CONCLUSION

Polaprezinc induced IGF-I production from mesenchymal cells, resulting in stimulation of epithelial cell restoration through a paracrine pathway. IGF-I may play an important role in gastric wound repair.

Monochloramine induced DNA fragmentation in gastric cell line MKN45

Monochloramine (NH2Cl) is known to be one of the virulence factors in Helicobacter pylori-associated gastric mucosal injury. The present study was designed to examine NH2Cl-evoked DNA fragmentation in the gastric epithelial cell line MKN45. NH2Cl was produced by mixing NH3 with sodium hypochlorite (NaClO). MKN45 cells were exposed to NH2Cl, NH3, or NaClO in Hanks' balanced salt solution. DNA cleavage was evaluated quantitatively by photometeric enzyme immunoassay for the in vitro determination of cytoplasmic mono- and oligonucleosomes. Damage to the plasma membrane was assessed by measuring the activity of lactate dehydrogenase in the supernatants. Separately, DNA ladder formation was performed to confirm the incidence of DNA fragmentation. NH2Cl (0.001-0.01 mM) significantly increased the cytoplasmic mono- and oligonucleosomes, suggesting the incidence of DNA cleavage. The DNA ladder was clearly evoked by NH2Cl. NH2Cl induced a DNA fragmentation, one of the important aspects in apoptosis, in the gastric cell line MKN45.

Anomalous junction of the pancreaticobiliary duct accompanied by gallbladder cancer and obstructive jaundice in a patient with high serum and bile cytokine levels

We report a case of anomalous junction of the pancreaticobiliary duct (AJPBD) associated with gallbladder cancer and obstructive jaundice in a patient with high serum and bile cytokine levels. The patient was a 63-year-old woman who complained of right hypochondralgia. Ultrasound, computed tomography, percutaneous transhepatic cholangiography, and endoscopic retrograde cholangio-pancreatatography revealed dilation of the bile ducts, an elevated lesion of the gallbladder, and AJPBD. She underwent percutaneous transhepatic cholangio-drainage (PTCD) for obstructive jaundice. However, the total bilirubin concentration remained high 7 days after PTCD. Her serum interleukin 6 level was 57,359 pg/ml before PTCD, and gradually decreased to 10 pg/ml after PTCD. Bile interleukin 6 level was 10 pg/ml before PTCD, 8997 pg/ ml 3 h after PTCD and gradually decreased there after. Serum and bile levels of tumor necrosis factor alpha and hepatocyte growth factor were high before and after PTCD. The patient underwent an extended cholecystectomy and resection of the extrahepatic bile duct. The resected specimen showed two elevated lesions of the gallbladder which, microscopically, revealed moderately differentiated tubular adenocarcinoma. These findings suggest that pre-existing inconspicuous inflammation of the biliary tract due to reflux of pancreatic juice is involved in elevation of serum and bile cytokines, and that cytokines may participate in gallbladder carcinogenesis associated with AJPBD.

Vacuolation induced by cytotoxin from Helicobacter pylori is mediated by the EGF receptor in HeLa cells

The bacterial toxin VacA produced by H. pylori induces large vacuoles in several types of cultured cells such as HeLa cells or gastric cells. To determine the mechanism of vacuolation induced by this toxin we employed several inhibitors of membrane trafficking and endocytosis. The development of vacuolation induced by VacA in HeLa cells were prevented by bafilomycin A1 and low temperature conditions that inhibited vesicle transport or endocytosis. Formation of large vacuoles was also inhibited by an antibody against EGF receptor, which was previously shown to be internalized by endocytosis, but not by an anti-transferrin receptor antibody. Moreover, proteins of 58 and 37 kDa, corresponding to fragments of VacA, were recognized by an anti-H. pylori antibody after immunoprecipitation with anti-EGF receptor of cell extracts from HeLa cells treated with VacA, but not from untreated HeLa cells. We suggest that VacA may enter cells by endocytosis mediated by the EGF receptor. These are the first data indicating that the EGF receptor may be significant in the development of vacuolation caused by VacA.

Reversal of MRP-mediated vincristine resistance in KB cells by buthionine sulfoximine in combination with PAK-104P

The mechanism of multidrug resistance protein (MRP)-mediated multidrug resistance (MDR) is still unclear. MRP reportedly transports some GSH conjugates. Recently, we demonstrated that a pyridine analog, 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), that reversed P-glycoprotein (P-gp)-mediated MDR directly interacted with MRP and completely reversed the vincristine (VCR) resistance in MRP-mediated MDR C-A120 cells. We investigated the reversing effect of PAK-104P in C-A120 cells in combination with buthionine sulfoximine (BSO), another MDR-reversing agent with a different reversing mechanism. In immunoblots, MRP was overexpressed in C-A120 cells. The level of ATP-dependent [3H]VCR uptake was high in membrane vesicles from KB-C2 cells, but low in those from C-A120 and parental KB-3-1 cells. The sensitivity to VCR of C-A120 cells, but not of KB-C2 cells, was considerably increased by 100 microM BSO. VCR accumulation in C-A120 cells, but not in KB-C2 cells, was also enhanced by BSO. BSO did not inhibit ATP-dependent [3H]LTC4 uptake in C-A120 vesicles. The combination of BSO with PAK-104P at their low concentrations resulted in complete reversal of VCR resistance in C-A120 cells. These findings suggested that BSO might not directly interact with MRP and reversed resistance in MRP-mediated MDR cells by reducing the intracellular glutathione (GSH) level that was needed for the transport of drugs by MRP and suggested a role for the combination of drug resistance-modulating agents with different reversing mechanisms in the reversal of MRP-mediated MDR.

Serum and bile interleukin 6 after percutaneous transhepatic cholangio-drainage

BACKGROUND/AIMS

This study was designed to assess the correlation of interleukin 6 (IL-6) with jaundice reduction by percutaneous transhepatic cholangio-drainage (PTCD) for obstructive jaundice.

METHODOLOGY

We measured serum and bile IL-6 concentrations by enzyme linked immuno-sorbent assay before and after PTCD in 26 patients with obstructive jaundice. The patients were divided into two groups according to their bilirubin decrease rate.

RESULTS

Serum IL-6 levels measured before and after PTCD in the slowly decreasing bilirubin group ("poor" group) were significantly higher than those of the rapidly decreasing bilirubin group ("good" group). Measures of bile IL-6 in the "poor" group remained high from 3 to 14 days after PTCD in comparison with the "good" group.

CONCLUSIONS

These results suggest that circulating IL-6, as well as IL-6 in the bile, may be involved in the pathogenesis of obstructive jaundice, and play an important role in preventing the resolution of obstructive jaundice after PTCD.

Prevalence of morphological changes in the surfaces of the temporomandibular joint disc associated with internal derangement

PURPOSE

The purpose of this study was to determine the prevalence of morphological changes in the superior and inferior surfaces in the temporomandibular joint (TMJ) disc and relate them to disc displacement.

MATERIALS AND METHODS

Thirty TMJs obtained from fresh cadavers were studied. The TMJs were dissected, and the superior and inferior surfaces of the disc were inspected and classified as intact, irregular, or perforated. These findings were corrolated to the position of the disc.

RESULTS

There was a greater prevalence of morphologic changes in the inferior (57%) than in the superior surface (17%) of the disc (P < .001). This was found for joints both with normal disc position and those with disc displacement. There was no relationship between surface irregularities of the inferior surface and the position of the disc. Perforation was seen more frequently in joints with disc displacement than in those with normal disc position.

CONCLUSION

Morphologic changes in the inferior surface of the TMJ disc are more prevalent than those in the superior surface, but this is not related to disc position. However, this needs to be considered when doing arthroscopy of only the superior joint compartment.

The biphasic effects of locus coeruleus noradrenergic activation on dendrodendritic inhibition in the rat olfactory bulb

Some forms of olfactory learning require intact noradrenergic terminals in the olfactory bulb that originate from the locus coeruleus. To clarify the action of noradrenergic inputs on the dendrodendritic interaction between mitral and granule cells in the rat olfactory bulb, we analyzed field potentials in the granule cell layer of the olfactory bulb evoked by paired-pulse stimulation of the lateral olfactory tract before and after the activation of the locus coeruleus. Locus coeruleus activation by glutamate injection in the vicinity of the nucleus changed only the test response without any effect on conditioning response. Paired-pulse inhibition measured from the ratio of test response amplitude to conditioning response amplitude was significantly depressed immediately after locus coeruleus activation. Conversely, 2 min later, paired-pulse inhibition was significantly potentiated. The significant potentiation of inhibition lasted for several minutes. The depression-potentiation sequence of paired-pulse inhibition was blocked by infusion of timolol, a beta-antagonist, into the olfactory bulb, in a dose-dependent manner, but not by infusion of phentolamine, an alpha-antagonist. Infusion of isoproterenol, a beta-agonist, into the bulb mimicked the depression of paired-pulse inhibition by locus coeruleus activation. These results suggest that glutamate activation of the locus coeruleus produces a depression-potentiation sequence in granule cell-mediated feedback inhibition onto mitral cells in the olfactory bulb through beta-adrenergic receptors.

[Changes in serum and bile tumor necrosis factor alpha before and after percutaneous transhepatic cholangio-drainage for obstructive jaundice]

The aim of this study was to evaluate the correlation between tumor necrosis factor alpha (TNF alpha) and jaundice reduction by percutaneous transhepatic cholangio-drainage (PTCD) in patients with obstructive jaundice. Thirty patients who had undergone PTCD were divided into two groups: those with rapidly decreasing bilirubin (the fast group; n = 21) and those with slowly decreasing bilirubin (the slow group; n = 9). We compared clinical features before PTCD between groups. We also compared serum and bile TNF alpha before and after PTCD in the fast group with those in the slow group. The rate of patients with recurrence of malignancy in other organs involved in the etiology of obstructive jaundice was significantly higher in the slow group than in the fast group. Before and after PTCD, serum and bile TNF alpha were significantly higher in the slow group than in the fast group. These results suggest that TNF alpha may play an important role in the protracted recovery from obstructive jaundice after PTCD.

[Guided tissue regeneration around dental implants in immediate extraction sockets: comparison of resorbable and nonresorbable membranes]

OBJECTIVE

This study was performed to compare the efficacy of guided tissue regeneration (GTR) around dental implants immediately placed into extraction sockets by resorbable or nonresorbable membranes.

METHODS

Mandibular P2, P3, and P4 of four adult beagle dogs were extracted bilaterally, and buccal standard defects were created and measured. Eighteen commercially pure titanium Steri-Oss implant fixtures were placed into the fresh extraction sockets. Four untreated implants were as controls, four implants received polytetrafluoroethylene (e-PTFE, Gore-Tex) membranes, five implants received collagen membranes, and five implants received polyglactin 910 mesh. After 14 weeks, clinical measurements were taken and the dogs were sacrificed and all specimens retrieved for histologic and histomophometric evaluation.

RESULTS

The average gain in bone height was 2.1 mm for untreated control sites, 3.3 mm for Gore-Tex sites, 3.8 mm for collagen sites, and 1.3 mm for polyglactin 910 sites.

CONCLUSION

The results of this study indicated that Gore-Tex and collagen membrane produced good results for GTR around implants. Collagen membrane can be a valid alternative to Gore-Tex membrane to improve bone regeneration around dental implants, while polyglactin 910 mesh seemed not suitable to be used as GTR membrane in immediate implantation for its high infection rate.

[Changes in airway space following mandibular setback using sagittal split ramus osteotomy with rigid internal fixation]

The changes in airway space following mandibular setback using sagittal split ramus osteotomy and rigid internal fixation were studied in 28 Japanese patients with mandibular prognathism. Lateral cephalometric radiographs were taken immediately before and shortly after surgery as well as 5 to 12 months postoperation. The mean setback of mandible was 8.3 mm in the right side, and 8.2 mm in the left side. The mean amount of relapse of pogonion point during the following-up period was 0.52 mm horizontally, and 0.92 mm vertically. A significant decrease in airway space width and area, espacially in the lower part of airway space was found following mandibular setback shortly after surgery. Although there was some increase both in airway space width and area during the following-up period, they did not increase to their original values. This suggests that the narrowing of airway space following mandibular setback using sagittal split osteotomy can be permanent. No significant correlation was found between the amount of mandibular setback and airway space changes, and no significant correlation was found between the amount of airway space changes and relapse of pogonion point during the following-up period.

Guided tissue regeneration around dental implants in immediate extraction sockets: comparison of resorbable and nonresorbable membranes

This study was performed to compare the efficacy of guided tissue regeneration (GTR) around dental implants immediately placed into extraction sockets by resorbable of nonresorbable membranes. Mandibular P2, P3, and P4 of four adult beagle dogs were extracted bilaterally, and buccal standard defects were created and measured. Eighteen commercially pure titanium Steri-Oss implant fixtures were placed into the fresh extraction sockets. Four implants were untreated controls, four implants received polytetrafluoroethylene (e-PTFE, Gore-Tex) membranes, five implants received collagen membranes (ParaGuide), and five implants received polyglactin 910 mesh (Vicryl). After 14 weeks, clinical measurements were taken and the dogs were sacrificed and all specimens retrieved for histologic and histomorphometric evaluation. The average gain in bone height was 2.1 mm for untreated control sites, 3.3 mm for Gore-Tex sites, 3.8 mm for collagen sites, and 1.3 mm for polyglactin 910 sites. The greatest gain in bone height and volume was seen for two sites that received Gore-Tex membranes and remained covered for the entire evaluation interval. The results of this study indicate that Gore-Tex and collagen membrane produced good results for GTR around implants immediately placed into extraction sockets. Since collagen membrane does not cause obvious infection and does not need the surgical reentry for membrane removal, it can be a valid alternative to Gore-Tex membrane to improve bone regeneration around dental implants, while polyglactin 910 mesh seems not suitable to be used as GTR membrane in immediate implantation for its high infection rate.

Changes in airway space following mandibular setback using sagittal split osteotomy and rigid internal fixation

The changes in airway space following mandibular setback using sagittal split osteotomy and rigid internal fixation were studied in 28 Japanese patients with mandibular prognathism. The correlation between the amount of mandibular setback and airway space changes, as well as the correlation between the amount of airway space changes and relapse of pognion point during the following-up period were also studied. Lateral cephalometric radiographs were taken immediately before and shortly after surgery as well as 5 to 12 months postoperation. The cephalometric evaluations of airway space width and area were based on stable craniofacial landmarks. The mean setback of mandible was 8.3 mm in the right side, and 8.2 mm in the left side. The mean amount of relapse of pogonion point during the following-up period was 0.52 mm horizontally, and 0.92 mm vertically. A significant decrease in airway space width and area, especially in the lower part of airway space was found following mandibular setback shortly after surgery. Although there was some increase both in airway space width and area during the following-up period, they did not increase to their original values. This suggests that the narrowing of airway space following mandibular setback using sagittal split osteotomy can be permanent. No significant correlation was found between the amount of mandibular setback and airway space changes. Since the relapse of pogonion point during the following-up period was too small, there is no significant correlation between it and the amount of airway space changes.

Reversal of multidrug resistance-associated protein-mediated drug resistance by the pyridine analog PAK-104P

Three agents, verapamil, cepharanthine, and 2-[4-(diphenylmethyl)-1-piperazinyl]ethyl-5-(trans-4,6-dimethyl-1, 3,2-dioxaphosphorinan-2-yl)-2,6-dimethyl-4-(3-nitrophenyl)-3-py ridinecarboxylate P-oxide (PAK-104P), that reverse drug resistance in P-glycoprotein (P-Gp)-mediated multidrug-resistant cells were examined for their activity to reverse drug resistance in multidrug resistance-associated protein (MRP)-mediated multidrug-resistant C-A120 cells. Agents other than PAK-104P could not reverse the resistance to doxorubicin in C-A120 cells. PAK-104P moderately reversed the doxorubicin resistance. In contrast, PAK-104P almost completely reversed the resistance to vincristine (VCR) in C-A120 cells as well as in KB-8-5 cells, and other agents moderately reversed the VCR resistance in C-A120 cells. PAK-104P at 10 microM enhanced the accumulation of VCR in C-A120 cells to the level of that in KB-3-1 cells without the agent. PAK-104P competitively inhibited the ATP-dependent [3H]leukotriene C4 uptake in membrane vesicles isolated from C-A120 cells. These findings demonstrate that PAK-104P can completely reverse the resistance to VCR in both P-Gp- and MRP-mediated multidrug-resistant cells and that PAK-104P directly interacts with MRP and inhibits the transporting activity of MRP.

[Tumor reduction in advanced renal cell carcinoma with tumor thrombus by renal embolization, interferon-alpha and UFT. A case report]

A 73-year-old man with renal cell carcinoma involving the left renal vein was treated with the embolization of the left renal artery followed by interferon-alpha and UFT. Computerized tomography revealed 53% reduction of the primary lesion and 47% reduction of the tumor thrombus 40 days after treatment. The histopathological study revealed marked lymphocyte infiltration and necrosis of the tumor after nephrectomy.