Split-mouth evaluation of connective tissue graft with or without enamel matrix derivative for the treatment of isolated gingival recession defects in dogs.

OBJECTIVES: The potential additive effect of an enamel matrix derivative (EMD) to a subepithelial connective tissue graft (CTG) for recession coverage is still controversially discussed. Therefore, the aim of this study was to histologically evaluate the healing of gingival recessions treated with coronally advanced flap (CAF) and CTG with or without EMD in dogs. MATERIALS AND METHODS: Gingival recession defects (5 mm wide and 7 mm deep) were surgically created on the labial side of bilateral maxillary canines in 7 dogs. After 8 weeks of plaque accumulation and subsequent 2 weeks of chemical plaque control, the 14 chronic defects were randomized to receive either CAF with CTG (CAF/CTG) or CAF with CTG and EMD (CAF/CTG/EMD). The animals were sacrificed 10 weeks after reconstructive surgery for histologic evaluation. RESULTS: Treatment with CAF/CTG/EMD demonstrated statistically significantly better results in terms of probing pocket depth reduction (P < 0.05) and clinical attachment level gain (P < 0.001). The length of the epithelium was statistically significantly shorter in the CAF/CTG/EMD group than in the CAF/CTG group (1.00 ± 0.75 mm vs. 2.38 ± 1.48 mm, respectively, P < 0.01). Cementum formation was statistically significantly greater in the CAF/CTG/EMD group than following treatment with the CAF/CTG group (3.20 ± 0.89 mm vs. 1.88 ± 1.58 mm, respectively, P < 0.01). The CAF/CTG/EMD group showed statistically significantly greater complete periodontal regeneration (i.e., new cementum, new periodontal ligament, and new bone) than treatment with CAF/CTG (0.54 ± 0.73 mm vs. 0.07 ± 0.27 mm, respectively, P < 0.05). CONCLUSION: Within their limits, the present findings indicate that the additional use of EMD in conjunction with CAF + CTG favors periodontal regeneration in gingival recession defects. CLINICAL RELEVANCE: The present findings support the use of EMD combined with CTG and CAF for promoting periodontal regeneration in isolated gingival recession defects.

Healing of localized gingival recessions treated with a coronally advanced flap alone or combined with an enamel matrix derivative and a porcine acellular dermal matrix: a preclinical study.

OBJECTIVE: This study aimed to evaluate the effects of a porcine acellular dermal matrix (PADM) with or without an enamel matrix derivative (EMD) on gingival recession defects treated with a coronally advanced flap (CAF) in dogs. MATERIALS AND METHODS: Miller class II gingival recession defects (5 mm wide and 7 mm deep) were surgically created on the labial side of bilateral maxillary canines in 12 dogs. After 8 weeks of plaque accumulation, the 24 chronic defects were randomly assigned to one of the following 4 treatments: CAF, CAF with PADM (CAF/PADM), CAF with EMD (CAF/EMD), and CAF with EMD and PADM (CAF/EMD/PADM). The animals were sacrificed 10 weeks after surgery for histologic evaluation. RESULTS: In all groups, root coverage was obtained to a varying degree. PADM was well incorporated in gingival connective tissue in the CAF/PADM and in the CAF/EMD/PADM groups. The height of newly formed bone was significantly greater in the CAF/EMD/PADM group than in the CAF and CAF/PADM groups. New cementum with periodontal ligament-like tissue was predominantly found in the CAF/EMD and CAF/EMD/PADM groups. The CAF/EMD/PADM group showed the greatest amount of new cementum among the groups examined, although the difference was not statistically significant. CONCLUSION: Within the limitations of the present study, it can be concluded that CAF/EMD/PADM treatment may promote periodontal regeneration in gingival recession defects. CLINICAL RELEVANCE: The present results suggest that the combination of EMD and PADM in conjunction with CAF may represent a promising approach for treating single Miller class II gingival recessions.

Periodontal healing after application of enamel matrix derivative in surgical supra/infrabony periodontal defects in rats with streptozotocin-induced diabetes.

BACKGROUND AND OBJECTIVE: Epidemiologic and clinical studies have indicated that diabetes is a risk factor for periodontal disease progression and healing. The aim of the present study was to evaluate short-term healing after enamel matrix derivative (EMD) application in combined supra/infrabony periodontal defects in diabetic rats. MATERIAL AND METHODS: Thirty male Wistar rats were initially divided into two groups, one with streptozotocin-induced diabetes and another one with healthy (non-diabetic) animals. Bony defects were surgically created on the mesial root of the first maxillary molars. After root surface planing and EDTA conditioning, EMD was applied to the roots at one side of the maxillae, while those on the contralateral sides were left untreated. Animals were killed 3 wk after surgery, and block sections were prepared for histologic and histomorphometric analysis. RESULTS: There was statistically significant more gingival recession in diabetic animals than in non-diabetic animals. The length of the junctional epithelium was significantly shorter in the EMD-treated sites in both diabetic and normoglycemic rats. Sulcus depth and length of supracrestal soft connective tissue showed no statistically significant differences between groups. In all animals, new bone formation was observed. Although new bone occurred more frequently in healthy animals, the extent of new bone was not significantly different between groups. In none of the teeth, a layer of new cementum was detectable. EMD had no influence on bone or cementum regeneration. Adverse reactions such as excessive inflammation due to bacterial root colonization, ankylosis and bone fractures were exclusively observed in diabetic animals, irrespective of EMD treatment. CONCLUSION: Within the limits of the present study, it can be concluded that periodontal healing was impaired in streptozotocin-induced diabetic rats. EMD had no beneficial effects on new bone and cementum formation during short-term healing in this defect model and could not ameliorate the adverse effects in the systemically compromised animals.

Effects of EMD in combination with bone swaging and calcium phosphate bone cement on periodontal regeneration in one-wall intrabony defects in dogs.

BACKGROUND AND OBJECTIVE: Although the application of EMD is a widely accepted periodontal-regenerative therapy, its effects on noncontained intrabony defects are unpredictable because of the lack of a space-making property. The combined use of EMD and autogenous bone grafts reportedly stimulates significant periodontal regeneration in intrabony defects. The aim of the present study was to evaluate the effects of EMD in combination with bone swaging (BS) and injectable calcium phosphate bone cement (CPC), which was placed into the spaces between the grafted swaged bone and the proximal host bone, on periodontal healing in one-wall intrabony defects in dogs. MATERIAL AND METHODS: One-wall intrabony defects (3 mm wide and 5 mm deep) were surgically created on the mesial and distal sides of the bilateral mandibular premolars in four dogs. The 16 defects were assigned to one of the following treatments: EMD only, BS only, EMD with BS (EMD + BS), or EMD with BS and CPC (EMD + BS + CPC). The animals were killed 8 wk after surgery for histologic evaluation. RESULTS: The height of newly formed bone was significantly greater in the EMD + BS + CPC group (3.73 ± 0.30 mm) than in the BS-only (2.74 ± 0.33 mm; p < 0.05) and EMD + BS (2.88 ± 0.98 mm; p < 0.05) groups. The area of newly formed bone was significantly larger in the EMD + BS + CPC group (5.68 ± 1.66 mm(2)) than in the EMD-only (3.68 ± 0.33 mm(2); p < 0.05), BS-only (3.48 ± 1.26 mm(2); p < 0.05) and EMD + BS (3.38 ± 1.37 mm(2); p < 0.05) groups. The EMD-only (4.63 ± 0.42 mm), EMD + BS (4.67 ± 0.30 mm) and EMD + BS + CPC (4.78 ± 0.54 mm) groups showed significantly greater cementum formation than did the BS-only group (3.93 ± 0.56 mm; p < 0.05). CONCLUSION: These results indicate that treatment with EMD + BS + CPC promotes favorable periodontal healing in one-wall intrabony defects in dogs.

Possible involvement of CD14+ CD16+ monocyte lineage cells in the epidermal damage of Stevens-Johnson syndrome and toxic epidermal necrolysis.

BACKGROUND: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are characterized by keratinocyte apoptosis and necrosis, resulting in epidermal detachment. Although monocytes abundantly infiltrate the epidermis in SJS/TEN skin lesions, the properties and functions of these cells have not been fully examined. OBJECTIVES: To determine the properties of monocytes infiltrating into the epidermis in SJS/TEN. METHODS: Immunostaining of skin sections was performed to examine the membrane markers of monocytes infiltrating into skin lesions. RESULTS: Immunostaining of cryosections from 11 SJS/TEN skin lesions revealed numerous CD14+ monocytes located along the dermoepidermal junction and throughout the epidermis. The cells coexpressed CD16, CD11c and HLA-DR. CD14+ CD16+ cells were identified in very early lesions without epidermal damage, suggesting that their infiltration is a cause, rather than a result, of epidermal damage. Moreover, these cells expressed CD80, CD86 and CD137 ligand, indicative of their ability to facilitate the proliferation and cytotoxicity of CD8+ T cells. CD16+ cells infiltrating the epidermis and detected at the dermoepidermal junction were immunostained and counted in paraffin-embedded skin sections obtained from 47 patients with drug rash manifested as TEN, SJS, maculopapular-type rash or erythema multiform-type rash. The number of CD16+ monocytes infiltrating the epidermis increased significantly, depending on the grade of epidermal damage. CONCLUSIONS: These findings suggest that the appearance of CD14+ CD16+ cells of monocyte lineage plays an important role in the epidermal damage associated with SJS/TEN, most probably by enhancing the cytotoxicity of CD8+ T cells.

Tumor necrosis factor receptor-associated factor 6 (TRAF6) stimulates extracellular signal-regulated kinase (ERK) activity in CD40 signaling along a ras-independent pathway.

CD40 activates nuclear factor kappa B (NF kappa B) and the mitogen-activated protein kinase (MAPK) subfamily, including extracellular signal-regulated kinase (ERK). The CD40 cytoplasmic tail interacts with tumor necrosis factor receptor-associated factor (TRAF)2, TRAF3, TRAF5, and TRAF6. These TRAF proteins, with the exception of TRAF3, are required for NF kappa B activation. Here we report that transient expression of TRAF6 stimulated both ERK and NF kappa B activity in the 293 cell line. Coexpression of the dominant-negative H-Ras did not affect TRAF6-mediated ERK activity, suggesting that TRAF6 may activate ERK along a Ras-independent pathway. The deletion mutant of TRAF6 lacking the NH2-terminal domain acted as a dominant-negative mutant to suppress ERK activation by full-length CD40 and suppress prominently ERK activation by a deletion mutant of CD40 only containing the binding site for TRAF6 in the cytoplasmic tail (CD40 delta 246). Transient expression of the dominant-negative H-Ras significantly suppressed ERK activation by full-length CD40, but marginally suppressed ERK activation by CD40 delta 246, compatible with the possibility that TRAF6 is a major transducer of ERK activation by CD40 delta 246, whose activity is mediated by a Ras-independent pathway. These results suggest that CD40 activates ERK by both a Ras-dependent pathway and a Ras-independent pathway in which TRAF6 could be involved.

Ras mediates effector pathways responsible for pre-B cell survival, which is essential for the developmental progression to the late pre-B cell stage.

Ras is essential for the transition from early B cell precursors to the pro-B stage, and is considered to be involved in the signal cascade mediated by pre-B cell antigen receptors. To examine the role of p21(ras) in the late stage of B cell differentiation, we established transgenic mice (TG) expressing a dominant-inhibitory mutant of Ha-ras (Asn-17 Ha-ras) in B lineage cells at high levels after the early B cell precursor stage. Expression of p21(Asn-17) (Ha-ras) was associated with a prominent reduction in the number of late pre-B cells, but had little effect on proliferation of early pre-B cells. Inhibition of p21(ras) activity markedly reduced the life span of pre-B cells, due, at least in part, to downregulation of the expression of an antiapoptotic protein, Bcl-xL. Thus, the apparent role for p21(ras) activity in pre-B cell survival may explain the decreased numbers of late pre-B cells in Asn-17 Ha-ras TG. Consistent with this possibility, overexpression of Bcl-2 in Asn-17 Ha-ras TG reversed the reduction in the number of late pre-B cells undergoing immunoglobulin light chain gene (IgL) rearrangement and progressing to immature B cells. These results suggest that p21(ras) mediates effector pathways responsible for pre-B cell survival, which is essential for progression to the late pre-B and immature B stages.

Ectodomain shedding of epidermal growth factor receptor ligands is required for keratinocyte migration in cutaneous wound healing.

Keratinocyte proliferation and migration are essential to cutaneous wound healing and are, in part, mediated in an autocrine fashion by epidermal growth factor receptor (EGFR)-ligand interactions. EGFR ligands are initially synthesized as membrane-anchored forms, but can be processed and shed as soluble forms. We provide evidence here that wound stimuli induce keratinocyte shedding of EGFR ligands in vitro, particularly the ligand heparin-binding EGF-like growth factor (HB-EGF). The resulting soluble ligands stimulated transient activation of EGFR. OSU8-1, an inhibitor of EGFR ligand shedding, abrogated the wound-induced activation of EGFR and caused suppression of keratinocyte migration in vitro. Soluble EGFR-immunoglobulin G-Fcgamma fusion protein, which is able to neutralize all EGFR ligands, also suppressed keratinocyte migration in vitro. The application of OSU8-1 to wound sites in mice greatly retarded reepithelialization as the result of a failure in keratinocyte migration, but this effect could be overcome if recombinant soluble HB-EGF was added along with OSU8-1. These findings indicate that the shedding of EGFR ligands represents a critical event in keratinocyte migration, and suggest their possible use as an effective clinical treatment in the early phases of wound healing.

Pre-B-cell leukemia transcription factor 1 is a major target of promyelocytic leukemia zinc-finger-mediated melanoma cell growth suppression.

Promyelocytic leukemia zinc-finger (PLZF) is a transcriptional repressor and tumor suppressor. PLZF is expressed in melanocytes but not in melanoma cells, and recovery of PLZF expression markedly suppresses melanoma cell growth. Several target genes regulated by PLZF have been identified, but the precise function of PLZF remains uncertain. Here, we searched for candidate target genes of PLZF by DNA microarray analysis. Pre-B-cell leukemia transcription factor 1 (Pbx1) was one of the prominently suppressed genes. Pbx1 was highly expressed in melanoma cells, and its expression was reduced by transduction with the PLZF gene. Moreover, the growth suppression mediated by PLZF was reversed by enforced expression of Pbx1. Knockdown of Pbx1 by specific small interfering RNAs suppressed melanoma cell growth. We also found that Pbx1 binds HoxB7. Reverse transcription-polymerase chain reaction analysis demonstrated that repression of Pbx1 by PLZF reduces the expression of HoxB7 target genes, including tumor-associated neoangiogenesis factors such as basic fibroblast growth factor, angiopoietin-2 and matrix metalloprotease 9. These findings suggest that deregulation of Pbx1 expression owing to loss of PLZF expression contributes to the progression and/or pathogenesis of melanoma.

Association of hepatitis B virus X protein with mitochondria causes mitochondrial aggregation at the nuclear periphery, leading to cell death.

Hepatitis B virus (HBV) X protein activates many viral and cellular genes in trans and functional disruption of the p53 tumor suppressor gene product occurs when X protein is transiently expressed in the cytoplasm of cultured cells. We have carried out investigations to determine the exact location of X protein in X gene transfected cells by using a fluorescent staining technique as well as by biochemical analyses. Aggregation of mitochondrial structures became evident at the periphery of nucleus in the cytoplasm of X transfected cells. X protein was found associated with the aggregated mitochondrial structures. Furthermore, transiently expressed p53 protein co-localized with X protein in X transfected cells. However, the appearance of aggregated mitochondrial structures at the nuclear periphery was independent of the presence of p53 protein in X transfected cells. X protein expression also caused an appearance of TUNEL positive nucleus, cytochrome c release from mitochondrial, the decrease of mitochondrial membrane potential and the membrane blebbing of X transfected cells, which are characteristic of cell death. Our data suggest that X protein causes an abnormal aggregation of mitochondrial structures in the cell, which may be eventually connected with cell death.

Characterization of decay-accelerating factor (DAF) in human skin.

Decay-accelerating factor (DAF) is a 70-kD membrane glycoprotein that regulates autologous complement activation, by preventing assembly of alternative or classical C3/C5 convertases, and has been shown to have a wide tissue distribution. In this study, DAF antigen has been demonstrated at the intercellular spaces of normal human epidermis with monoclonal antibody against DAF using the peroxidase-anti-peroxidase method. The amount of DAF was greater at the granular layer than the basal cell layer as judged by intensity of the staining. Western blot analysis of DAF in the epidermis showed a 55-kD band, whereas that of buffy coat cells was approximately 67 kD. When DAF of the epidermis was treated with neuraminidase, the molecular weight was reduced to 53 kD, whereas that of buffy coat cells was 56 kD. These results indicated that the content of sialic acid of DAF in the epidermis was different from that of buffy coat cells. In phosphatidylinositol-specific phospholipase C (PIPLC)-treated normal human skin, DAF was not demonstrated in the epidermis, whereas DAF remained unchanged on the elastic fibers. After the treatment of the epidermis by PIPLC, DAF was released into the buffer shown by Western blot analysis. These results suggested that DAF on the epidermis was anchored to keratinocyte via phosphatidylinositol (PI), whereas the anchoring mechanism of DAF on the elastic fibers was not through PI.

Lack of mucosal involvement in pemphigus foliaceus may be due to low expression of desmoglein 1.

Oral mucosal lesions are seen in most cases of pemphigus vulgaris, whereas they are only rarely seen in pemphigus foliaceus; however, both pemphigus vulgaris and pemphigus foliaceus sera show positive immunofluorescence staining on oral mucosa. To explain this apparent paradox, we examined the expression level of desmoglein (Dsg)3, pemphigus vulgaris antigen, and Dsg1, pemphigus foliaceus antigen, in human squamous mucosal epithelia and epidermis by immunofluorescence staining and immunoblotting. For immunofluorescence staining, Dsg isotype-specific antibodies were produced by immunoadsorbing pemphigus vulgaris sera with either recombinant Dsg1 or Dsg3 baculoprotein. In oral mucosa and esophagus both Dsg were immunoreactive on cell surfaces throughout the entire epithelia, but staining intensity was weaker for Dsg1 than for Dsg3. Immunoblotting was performed to compare Dsg1 and Dsg3 expression levels in extracts from epidermis and oral mucosa. The total amount of desmosomal proteins applied was adjusted to give the same degree of staining intensity for desmoplakin, a cytoplasmic plaque protein of desmosomes. In the mucosal extract, the Dsg1 band was much weaker than Dsg3, whereas in the epidermal extract the Dsg1 band was stronger than Dsg3. These data suggest that although Dsg1 and Dsg3 are expressed in a similar distribution throughout squamous mucosal epithelia, Dsg1 is expressed at a much lower level than Dsg3. This finding provides a good explanation for the paradox: even though anti-Dsg1 autoantibodies block the function of Dsg1 in the mucosal epithelia, Dsg3 may be sufficient for cell-cell adhesion, with consequently no apparent oral involvement in pemphigus foliaceus patients.

Expression and characterization of membrane co-factor protein (MCP) in human skin.

Membrane co-factor protein (MCP; CD46) is an integral membrane protein with molecular weight (MW) of the two species of 63 kD and 55 kD, and regulates autologous complement activation, with the activity of factor I cofactor. The quantity of each species is genetically regulated, and two codominantly inherited allelic variants account for the three phenotypic patterns. By immunohistochemical study, MCP was found both in the intercellular spaces of the epidermis and on the endothelial cells in the dermis of normal human skin in vivo. The intensity of the staining pattern was higher in the basal layer than in the granular layer. By Western blot analysis with use of a monoclonal antibody, MCP in the epidermis appeared as several bands ranged from 60-50 kD, with a major band of 56 kD, which was different from those in either polymorphonuclear cells, platelets, and cultured keratinocytes. No other variants were found in the epidermis obtained from skin of 20 normal humans. Complement activation in human skin may be regulated at several steps, including DAF and HRF20, thereby protecting cells from autologous complement attack.

Inhibitory effect of plasma FKBP12 on immunosuppressive activity of FK506.

To evaluate the roles of extracellular FKBP12, we examined the effect of extracellular FKBP12 on the immunosuppressive activity of FK506 in vitro and clinically. The ability of FK506 to suppress phytohemagglutinin-induced proliferative response of human peripheral blood mononuclear cells was inhibited in the presence of recombinant FKBP12 dose-dependently. We measured plasma levels of FKBP12 using a newly developed enzyme-linked immunosorbent assay system in 34 patients receiving FK506 after liver transplantation. In 7 patients with acute cellular rejection, plasma FKBP12 increased significantly at the onset of rejection compared with 1 week before onset (P < 0.05) and further increased to or remained at more than 250 ng/ml 1 week after onset. In 22 of 27 patients without acute cellular rejection, plasma FKBP12 was less than 70 ng/ml during the 4 weeks after transplantation. In the other 5 of 27 patients without acute cellular rejection, plasma FKBP12 exceeded 250 ng/ml. Rapid increase of plasma FKBP12 was observed in only one of these 5 patients, at the onset of high fever due to a liver abscess. There was no significant difference in whole blood trough levels of FK506 between the patients with or without acute cellular rejection. These results suggest that the rapid increase in plasma levels of FKBP12 may contribute to the occurrence and progress of acute cellular rejection probably by inhibiting the immunosuppressive activity of FK506.

Successful long-term xenoperfusion of the pig liver: continuous administration of prostaglandin E1 and insulin.

For clinical utilization of extracorporeal liver perfusion as an artificial liver assist device, we examined the possibility of long-term xenoperfusion of the pig liver by the continuous administration of prostaglandin E1 (PGE1) and insulin. After a 3-hr perfusion period, pig livers that were xenoperfused with human blood exhibited a drastic decrease in the perfusate volume, a progressive elevation of the hepatic artery pressure, a gradual deterioration of bile production, and a marked increase in the release of creatine kinase-BB component. The continuous administration of PGE1 (25 microg/hr) and insulin (1 U/hr) significantly improved these derangements (P<0.05) and allowed stable perfusion for up to 9 hr. This manipulation also inhibited leukocyte aggregation in the graft, the characteristic perfusate hemolysis, and acceleration of ketogenesis. Histological examination revealed that the interlobular edema and hemorrhage, characteristics of tissue injuries in xenogeneic hyperacute rejection, were markedly alleviated in the PGE1 and insulin-treated group. This study clarifies the finding that the combined administration of PGE1 and insulin is effective for long-term xenogeneic extracorporeal liver perfusion, with the graft viability well maintained.

Expression of vitamin D receptor in cultured human keratinocytes and fibroblasts is not altered by corticosteroids.

Topical vitamin D3 therapy is one of the mainstays of psoriasis treatment. However, the effectiveness of combination therapy with topical vitamin D3 and corticosteroids is still controversial. It has been reported that topical vitamin D3 treatment following topical corticosteroids is less effective than that without preceding corticosteroid treatment. We hypothesized that vitamin D receptor (VDR) in the skin is down-regulated by topical corticosteroids. To obtain support for this hypothesis, we determined VDR protein levels in cultured keratinocytes and fibroblasts after corticosteroid treatment. VDR levels were quantified by Western blot analysis with a Fluorolmager. Keratinocytes and fibroblasts were obtained from four psoriasis patients and four normal controls. VDR levels were altered in neither normal nor psoriatic keratinocytes by 2-day incubation with dexamethasone (1x10(-9)-1x10(-6) M) or clobetasol propionate (1x10(-9)-1x10(-6) M). Similarly, VDR levels in normal and psoriatic fibroblasts were not affected by 2-day incubation with dexamethasone (1x10(-6) M). These findings suggest that down-regulation of VDR by topical corticosteroids in keratinocytes and fibroblasts of psoriasis is unlikely.

Isolation and characteristics of scallop sarcoplasmic reticulum with calcium transport activity.

Sarcoplasmic reticulum with calcium transport activity has been isolated from the cross-striated adductor muscle of the scallop, which lives in cold (< or = 20 degrees C) sea water, by using pH 7.0 buffer solution both to homogenize the tissue and to sediment the membrane fraction. The yield of the preparation was 60-100 mg protein from 100 g of the scallop muscle. Ca(2+)-activated ATPase protein of about 100 kDa accounted for 40-50% of the protein preparation. The maximum activities of ATP-dependent, oxalate-facilitated calcium accumulation and Ca(2+)-ATPase were observed at a pH of about 7.0 and temperature of 20-30 degrees C, and their values were about 2 mumol Ca2+/mg of protein/min and about 3 mumol ATP hydrolysis/mg of protein/min, respectively. At 0 degree C, 10-20% of these activities was maintained, while at 37 degrees C, the activities were irreversibly lost. The Ca(2+)-ATPase activity was half-maximally activated at about 0.3 microM [Ca2+]. The ATPase activity exhibited non-Michaelian behavior with respect to ATP, with two different Km values of approximately 10 microM and 0.1-0.3 mM. GTP, CTP, and ITP were also hydrolyzed by the preparation at a rate of 10-30% of that of ATP. The preparation was stored at -80 degrees C with retention of function for about a year.

Experiences of 120 microsurgical reconstructions of hepatic artery in living related liver transplantation.

BACKGROUND: We reviewed 120 microsurgical reconstructions of a hepatic artery in living related liver transplantation and discussed the problems encountered. METHODS: From January 1991 to July 1994 we performed a series of 105 living related liver transplantations on children with end-stage liver disease. Arterial reconstruction was performed under the optical field of a continuous zoom magnification of approximately 10 times with an operating microscope. RESULTS: Twenty-six percent of the graft arteries were less than 2 mm in diameter. The time required for an arterial reconstruction was 49.5 +/- 1.8 minutes. In 15 of the 31 cases in which there were two graft arteries, two arterial reconstructions were required. The caliber differences between the graft artery and the recipient artery in 30 instances was dealt with by cutting an undersized artery obliquely (17 instances), by fish-mouth method (10 instances), by end-to-side anastomosis (1 instance), or by funnelization method (2 instances). In one case we performed an intimal dissection of a recipient hepatic artery and substituted a splenic artery. Consequently, hepatic arterial thrombosis occurred in only two cases (1.7%). CONCLUSIONS: Microsurgical technique has overcome the high risk of hepatic arterial thrombosis in cases of fine graft arteries, enabled the reconstruction of arteries with caliber difference, and decreased arterial complications with its delicate manipulation.

Twenty-four hour monitoring of pH in the gastric tube replacing the resected esophagus.

BACKGROUND: Peptic ulcers in the gastric tube replacing the resected esophagus develop silently and cause serious problems. In this study, the acidity of the gastric tube was examined by 24-hour pH monitoring to determine if the acidity of the gastric tube was sufficient to cause peptic ulcers. STUDY DESIGN: The acidity of a gastric tube was evaluated by 24-hour pH monitoring of both the fundus and the antrum in 55 patients treated for carcinoma of the esophagus. The correlation between the fasting serum gastrin concentration and the intraluminal acidity of the completely vagotomized gastric tube was examined. RESULTS: In the patients with high postoperative acidity in the fundus or the antrum (46 percent of the 41 patients examined), the intraluminal pH remained consistently low, even long after operative treatment. Significant correlations existed between the percentage of time that the pH remained below 3 preoperatively and postoperatively in both the fundus and the antrum (r = 0.4777, p = 0.0386, and r = 0.7597, p = 0.0002, respectively). The percentage did not decrease significantly postoperatively. A significantly negative correlation (r = -0.783401, p < 0.0001) was found between the fasting serum gastrin level and the proportion of time that the nocturnal pH in the antrum remained below 3. CONCLUSIONS: Even long after esophagectomy, the pH of the gastric tube is low enough to cause peptic ulcers, especially in patients with high preoperative acidity. In these patients, the intraluminal pH in the antrum of the gastric tube correlates inversely with the fasting serum gastrin level.

Endothelin-induced activation of Cl- channels of guinea pig parietal cells.

The addition of endothelin-1 to the bath solution dose-dependently increased the whole-cell Cl- currents in single parietal cells isolated from guinea pig stomach. NPPB dose-dependently inhibited the current. Endothelin-3 was also effective, though less than endothelin-1.