Microwave coagulation therapy for multiple hepatic metastases from colorectal carcinoma

BACKGROUND

Compared with other treatments, microwave coagulation is a relatively less invasive treatment for various kinds of solid tumors. Although its effectiveness in primary hepatocellular carcinoma has been shown, its effectiveness in the treatment of hepatic metastases from colorectal carcinoma has been unclear. The aim of this study was to evaluate its effectiveness in the treatment of multiple hepatic metastases from colorectal carcinoma by comparing this technique with that of hepatic resection.

METHODS

Thirty patients with multiple metastatic colorectal tumors in the liver who were potentially amenable to hepatic resection were randomly assigned to treatment with microwave coagulation (14 patients) or hepatectomy (16 patients). Tumors in the microwave group were coagulated after laparotomy at an output of 60-100 W for 2-20 minutes under the guide of ultrasonography, whereas tumors in the hepatectomy group were treated with lobectomy, segmentectomy, subsegmentectomy, and/or wedge resection.

RESULTS

One-, 2-, and 3-year survival rates and mean survival times were 71%, 57%, 14%, and 27 months, respectively, in the microwave group, whereas they were 69%, 56%, 23%, and 25 months, respectively, in the hepatectomy group. The difference between these two groups was statistically not significant (P = 0.83). On the other hand, the amount of intraoperative blood loss in the microwave group (360 +/- 230 mL) was smaller than that in the hepatectomy group (910 +/- 490 mL, P < 0.05). Blood transfusion was necessary for 6 patients in the hepatectomy group, but it was not necessary in the microwave group.

CONCLUSIONS

Microwave coagulation therapy is suggested to be equally effective as hepatic resection in the treatment of multiple (two to nine) hepatic metastases from colorectal carcinoma, whereas its surgical invasiveness is less than that of hepatic resection.

Microwave coagulation therapy for multiple hepatic metastases from colorectal carcinoma

BACKGROUND

Compared with other treatments, microwave coagulation is a relatively less invasive treatment for various kinds of solid tumors. Although its effectiveness in primary hepatocellular carcinoma has been shown, its effectiveness in the treatment of hepatic metastases from colorectal carcinoma has been unclear. The aim of this study was to evaluate its effectiveness in the treatment of multiple hepatic metastases from colorectal carcinoma by comparing this technique with that of hepatic resection.

METHODS

Thirty patients with multiple metastatic colorectal tumors in the liver who were potentially amenable to hepatic resection were randomly assigned to treatment with microwave coagulation (14 patients) or hepatectomy (16 patients). Tumors in the microwave group were coagulated after laparotomy at an output of 60-100 W for 2-20 minutes under the guide of ultrasonography, whereas tumors in the hepatectomy group were treated with lobectomy, segmentectomy, subsegmentectomy, and/or wedge resection.

RESULTS

One-, 2-, and 3-year survival rates and mean survival times were 71%, 57%, 14%, and 27 months, respectively, in the microwave group, whereas they were 69%, 56%, 23%, and 25 months, respectively, in the hepatectomy group. The difference between these two groups was statistically not significant (P = 0.83). On the other hand, the amount of intraoperative blood loss in the microwave group (360 +/- 230 mL) was smaller than that in the hepatectomy group (910 +/- 490 mL, P < 0.05). Blood transfusion was necessary for 6 patients in the hepatectomy group, but it was not necessary in the microwave group.

CONCLUSIONS

Microwave coagulation therapy is suggested to be equally effective as hepatic resection in the treatment of multiple (two to nine) hepatic metastases from colorectal carcinoma, whereas its surgical invasiveness is less than that of hepatic resection.

Lack of an association between T-wave alternans and ST-segment depression during exercise-induced ambulatory ischemia

It is known that T-wave alternans (TWA), which identify patients at risk for arrhythmic events, often occur during acute coronary occlusion in association with ST-segment elevation. To test the hypothesis that TWA is associated with a certain state/severity of myocardial infarction/ischemia, we assessed the association between TWA and ST-segment depression during exercise-induced ambulatory ischemia. Of 351 consecutive patients with coronary artery disease who underwent assessment of microvolt TWA by exercise, 23 patients with effort angina without a history of infarction with ST depression (> or =0.11 mV) during TWA test were selected. These patients were compared with 222 postinfarction patients consisting of 38 patients with, and 184 patients, without the ST depression, and 18 normal individuals. The incidence (9%) of determinate TWA in the patients with angina was significantly (P < .0001) lower than that (52%) in the postinfarction patients. There was no significant difference between the angina patients and the controls (6%). There was also no difference between the patients with (58%) and without the ST depression (51%) in the postinfarction patients. Moreover, no correlation existed between the TWA voltage and the ST-depression magnitude in both angina and postinfarction patients. We concluded that there is no association between TWA and ambulatory ischemia with ST depression.

Receptor activator of NF-kappaB ligand induces the fusion of mononuclear preosteoclasts into multinucleated osteoclasts

The osteoclasts are bone-resorbing multinucleatedcells formed by the fusion of mononuclearpreosteoclasts (pOCs) of hematopoietic origin.Although receptor activator of NF-kappaBligand (RANKL) has been shown to regulate osteoclastdifferentiation and function, its effect on the fusionof pOCs into multinucleated osteoclast-like cells(OCLs) has not been known. Using our fusion assaysystem, that is not contaminated with multinucleatedcells (MNCs) and osteoblastic cells, we determined theeffect of RANKL on the fusion of pOCs into MNCs. WhenpOCs were cultured on the plates, most of pOCs diedand disappeared from the plates within 24 h in theabsence of additives, but pOCs were fused to MNCswithin 6 h in the presence of RANKL. RANKL-inducedMNCs showed typical properties of OCL such astartrate-resistant acid phosphatase (TRAP) activity,actin ring formation, and bone-resorbing activity. Thefusion of pOCs into OCLs induced by osteoblastic cellsor RANKL was inhibited by OPG/OCIF, but that inducedby IL-1beta was not. Both RANKL- andIL-1beta-induced OCL formation from pOCs wasinhibited by ZLLL-H, a peptide inhibitor ofproteasome. These findings indicate that RANKLsupports the survival of pOCs and induces the fusionof pOCs into OCLs and suggest that NF-kappaBactivation is involved in these processes induced byRANKL and IL-1beta.

Eicosatetraynoic and eicosatriynoic acids, lipoxygenase inhibitors, block meiosis via antioxidant action

We previously showed that nordihydroguaiaretic acid (NDGA) and other antioxidants inhibit the resumption of meiosis in oocyte-cumulus complexes (OCC) and denuded oocytes (DO). Because NDGA is well known to be an inhibitor of lipoxygenases (LOX), we assessed whether other LOX inhibitors influence spontaneous germinal vesicle breakdown (GVBD) in OCC and DO. Spontaneous GVBD in rat OCC obtained from preovulatory follicles was significantly and reversibly inhibited by the minimum effective doses of 80 and 100 microM 5,8,11, 14-eicosatetraynoic acid (ETYA) and 5,8,11-eicosatriynoic acid (ETI), respectively. In DO, GVBD was significantly inhibited by 100 microM ETYA or ETI. The minimum effective concentrations of ETYA and ETI for inhibition of GVBD in either OCC or DO are approximately 30- to 50-fold higher than the concentrations necessary to inhibit LOX activity by 50% in intact cells. Because we previously showed that NDGA and other antioxidants inhibit the spontaneous resumption of meiosis, we assessed whether ETYA and ETI may act similarly as scavengers of reactive oxygen species (ROS). Luminol-amplified chemiluminescence showed that 50 microM of either ETYA or ETI markedly and significantly reduced ROS generated with 10 mM 2, 2'-azobis(2-amidinopropane)dihydrochloride (AAPH). Moreover, incubation of DO with 30 mM AAPH reversed the inhibition of GVBD produced by 100 microM ETYA or ETI. These findings support the conclusion that ETYA and ETI inhibit oocyte maturation by acting as antioxidants rather than by inhibiting LOX.

Combined assessment of T-wave alternans and late potentials used to predict arrhythmic events after myocardial infarction. A prospective study

OBJECTIVES

The aim of the present study was to determine whether the combination of two markers that reflect depolarization and repolarization abnormalities can predict future arrhythmic events after acute myocardial infarction (MI).

BACKGROUND

Although various noninvasive markers have been used to predict arrhythmic events after MI, the positive predictive value of the markers remains low.

METHODS

We prospectively assessed T-wave alternans (TWA) and late potentials (LP) by signal-averaged electrocardiogram (ECG) and ejection fraction (EF) in 102 patients with successful determination results after acute MI. The TWA was analyzed using the power-spectral method during supine bicycle exercise testing. No antiarrhythmic drugs were used during the follow-up period. The study end point was the documentation of ventricular arrhythmias.

RESULTS

The TWA was present in 50 patients (49%), LP present in 21 patients (21%), and an EF <40% in 28 patients (27%). During a follow-up period of 13 +/- 6 months, symptomatic, sustained ventricular tachycardia or ventricular fibrillation occurred in 15 patients (15%). The event rates were significantly higher in patients with TWA, LP, or an abnormal EF. The sensitivity and the negative predictive value of TWA in predicting arrhythmic events were very high (93% and 98%, respectively), whereas its positive predictive value (28%) was lower than those for LP and EF. The highest positive predictive value (50%) was obtained when TWA and LP were combined.

CONCLUSIONS

The combined assessment of TWA and LP was associated with a high positive predictive value for an arrhythmic event after acute MI. Therefore, it could be a useful index to identify patients at high risk of arrhythmic events.

Tumor necrosis factor alpha stimulates osteoclast differentiation by a mechanism independent of the ODF/RANKL-RANK interaction

Osteoclast differentiation factor (ODF, also called RANKL/TRANCE/OPGL) stimulates the differentiation of osteoclast progenitors of the monocyte/macrophage lineage into osteoclasts in the presence of macrophage colony-stimulating factor (M-CSF, also called CSF-1). When mouse bone marrow cells were cultured with M-CSF, M-CSF-dependent bone marrow macrophages (M-BMM phi) appeared within 3 d. Tartrate-resistant acid phosphatase-positive osteoclasts were also formed when M-BMM phi were further cultured for 3 d with mouse tumor necrosis factor alpha (TNF-alpha) in the presence of M-CSF. Osteoclast formation induced by TNF-alpha was inhibited by the addition of respective antibodies against TNF receptor 1 (TNFR1) or TNFR2, but not by osteoclastogenesis inhibitory factor (OCIF, also called OPG, a decoy receptor of ODF/RANKL), nor the Fab fragment of anti-RANK (ODF/RANKL receptor) antibody. Experiments using M-BMM phi prepared from TNFR1- or TNFR2-deficient mice showed that both TNFR1- and TNFR2-induced signals were important for osteoclast formation induced by TNF-alpha. Osteoclasts induced by TNF-alpha formed resorption pits on dentine slices only in the presence of IL-1alpha. These results demonstrate that TNF-alpha stimulates osteoclast differentiation in the presence of M-CSF through a mechanism independent of the ODF/RANKL-RANK system. TNF-alpha together with IL-1alpha may play an important role in bone resorption of inflammatory bone diseases.

Cloning of bovine LYST gene and identification of a missense mutation associated with Chediak-Higashi syndrome of cattle

An inheritable bleeding disorder with light coat color caused by an autosomal recessive gene has been reported in a population of Japanese black cattle. The disease has been diagnosed as Chediak-Higashi Syndrome (CHS) of cattle which correspond to a human inheritable disorder caused by mutation in LYST gene. To characterize the molecular lesion causing CHS in cattle, cDNAs encoding bovine LYST were isolated from a bovine brain cDNA library. The nucleotide and deduced amino acid sequences of bovine LYST had 89.6 and 90.2% identity with those of the human LYST gene, respectively. In order to identify the mutation within the LYST gene causing CHS in cattle, cDNA fragments of the LYST gene were amplified from an affected animal by RT-PCR and their nucleotide sequences were completely determined. Notably, a nucleotide substitution of A to G transition, resulting in an amino acid substitution of histidine to arginine (H2015R) was identified in the affected animal. The presence of the substitution was completely corresponding with the occurrence of the CHS phenotype among 105 members of pedigrees of the Japanese black cattle and no cattle of other populations had this substitution. These findings strongly suggested that H2015R is the causative mutation in CHS of Japanese black cattle.

Osteoblastic cells induce fusion and activation of osteoclasts through a mechanism independent of macrophage-colony-stimulating factor production

Fusion and activation of osteoclasts are the final two events in osteoclastic bone resorption. To investigate the regulatory mechanism of these events, mononuclear osteoclasts (preosteoclasts, pOCs) were isolated from co-cultures of mouse osteoblastic cells and bone marrow cells. Most of the pOCs cultured without any additives died within 12 h. Survival of pOCs was supported by addition of either osteoblastic cells or macrophage-colony-stimulating factor (M-CSF). pOCs began to fuse with each other after culture for 12 h in the presence of osteoblastic cells or M-CSF. However, the properties of multinucleated osteoclast-like cells (OCLs) induced by osteoblastic cells were considerably different from those induced by M-CSF. Fusion of pOCs induced by osteoblastic cells was retarded after culture for 24 h. In contrast, M-CSF-induced fusion of pOCs continued throughout the 48-h culture period, which was not inhibited by addition of calcitonin. When pOCs together with osteoblastic cells were cultured for 48 h on dentine slices, many resorption pits were formed on the slices. Calcitonin completely inhibited the fusion and pit-forming activity of pOCs treated with osteoblastic cells. Resorption pits were hardly detected on dentine slices in pOC cultures treated with M-CSF. Osteoblastic cells prepared from osteopetrotic (op/op) mice, which cannot produce functional M-CSF, stimulated the fusion and pit-forming activity of pOCs. Recombinant RANKL (receptor activator of NF-kappaB ligand), a cytokine which is produced by osteoblastic cells and is responsible for osteoclast differentiation, induced the fusion and pit-forming activity of pOCs. These results suggested that osteoblastic cells are involved in fusion and activation of osteoclasts through a mechanism independent of M-CSF production. RANKL appears to be responsible for fusion and activation of osteoclasts induced by osteoblastic cells.

[Microwave coagulation therapy under laparotomic ischemia for multiple liver metastases of colorectal cancer]

Microwave coagulation therapy (MCT) under laparotomic ischemia induced by partial obstruction of the hepatic artery and portal vein was conducted on patients with multiple liver metastases of colorectal cancer. The patients were then compared with those who underwent non-ischemic MCT. Among the patients with liver metastasis of colorectal cancer we encountered between August 1990 and October 1998, 14 patients who developed multiple cancer (five or more) in the bilateral liver lobes were enrolled in the study. No clear differences were observed in the sex, age, frequency of simultaneousness, therapy other than MCT, number of foci, and number of MCT between the ischemic MCT and non-ischemic MCT group. Postoperative CT revealed residual foci in one of the seven patients in the ischemic MCT group. A comparison of the cumulative survival rate revealed that the ischemic MCT group had a higher one-year survival rate (50%) than the non-ischemic MCT group (14%). A comparison of patients with a residual lesion and those with no residual lesion showed that all six patients with a residual lesion died less than one year after surgery. Eight patients with no residual lesion had a significantly better prognosis (p < 0.05). It is important to eliminate any residual metastatic lesion during surgery in multiple liver metastases of colorectal cancer If the residual lesion is non-resectable, its elimination by ischemic MCT would contribute to the long-term survival of the patients.

Pharmacokinetics of 9alpha-fluoromedroxyprogesterone acetate in rats: comparison with medroxyprogesterone acetate

Medroxyprogesterone acetate (MPA) is widely used in endocrine therapy for breast cancer and other diseases. Recently, it has been demonstrated that 9alpha-fluoromedroxyprogesterone acetate (FMPA) also has anti-tumour activity in chemical-induced rat mammary tumour and its activity is greater than that of MPA. In the present study, the physico-chemical properties of FMPA and MPA and their pharmacokinetics in female rats were investigated. Partition coefficients (log P) of FMPA and MPA were 3.1 and 3.8, respectively, while the solubilities of FMPA and MPA in phosphate buffer saline were 3.8 and 1.1 microg/mL, respectively. When the two agents were intravenously or orally administered into female rats, there was no significant difference between their plasma concentrations. However, unmetabolized drug excreted into urine accounted for 4.7 and 0.7% of the intravenous dose of FMPA and MPA, respectively. The free fraction of FMPA in rat plasma was approximately four times that of MPA. Assuming the well-stirred model, hepatic intrinsic clearances of FMPA and MPA were estimated to be 64 and 293 L/h per kg, respectively. In addition, the free fraction of FMPA in blood is estimated to be higher than that of MPA, which may explain the higher anti-tumour activity.

A simple technique for anatomical slow pathway ablation in atrioventricular nodal reentrant tachycardia

The slow pathway potential or the slow potential serves as a useful marker in catheter ablation of the slow pathway. However, an anatomical approach without recording of these potentials is also an effective way to cure atrioventricular nodal reentrant tachycardia (AVNRT). Moreover, the origin of these potentials is a matter of controversy. We compared 2 approaches to ascertain whether or not recording of these potentials is necessary in eliminating the slow pathway and to estimate the usefulness of the simple anatomical approach. The study population consisted of 24 patients with a conventional approach (Group P) and 19 patients with an anatomical approach (Group A). In group A, the ablation site was determined by fluoroscopy, which was the lowest one-third of the area between the His bundle electrogram recorded position and the coronary sinus orifice at the right anterior oblique view, and just in front of and above the coronary sinus orifice also posterior to the His catheter at the left anterior oblique view where the His catheter was seen tangentially. The slow pathway was successfully ablated in all patients without any complications, including more than first-degree AV block. Although there were no significant differences in total energy or number of applications between the 2 groups, the procedure time was significantly shorter in group A (p < 0.01). In conclusion, recording of the slow pathway potential or the slow potential is not always necessary for slow pathway ablation in the treatment of AVNRT. Because our anatomical approach was performed simply, effectively and safely, it is recommended for the slow pathway ablation of AVNRT.

Localization of a locus responsible for the bovine chondrodysplastic dwarfism (bcd) on chromosome 6

A hereditary chondrodysplastic dwarfism caused by an autosomal recessive gene has been reported in a population of Japanese Brown cattle. Affected calves show an insufficiency of endochondral ossification at the long bones of the limbs. In the present study, we mapped the locus responsible for the disease (bcd) by linkage analysis, using microsatellite markers and a single paternal half-sib pedigree obtained from commercial herds. Linkage analysis revealed a significant linkage between the bcd locus and marker loci on the distal region of bovine Chromosome (Chr) 6. The bcd locus was mapped in the interval between microsatellite markers BM9257 and BP7 or BMS511 with a recombination fraction of 0.05 and 0.06, and a lod score of 8.6 and 10.1, respectively. A comparison of genetic maps between bovine Chr 6 and human Chr 4 or mouse Chr 5 indicates possible candidate genes including FGFR3 and BMP3 genes, which are responsible for human chondrodysplasias and associated with bone morphogenesis, respectively.

Antioxidants reversibly inhibit the spontaneous resumption of meiosis

We previously showed that the cell-permeant antioxidant 2(3)-tert-butyl-4-hydroxyanisole (BHA) inhibited germinal vesicle breakdown (GVBD) in oocyte-cumulus complexes (OCC) of the rat. The objective of the present studies was to assess other antioxidants and whether such inhibition was reversible. Spontaneous GVBD in OCC incubated for 2 h was significantly inhibited (P < 0.005) by nordihydroguaiaretic acid (NDGA; GVBD = 19.4%), BHA (GVBD = 25.7%), octyl gallate (OG; GVBD = 52.2%), ethoxyquin (EQ; GVBD = 58.8%), 2, 6-di-tert-butyl-hydroxymethyl phenol (TBHMP; GVBD = 59%), butylated hydroxytoluene (BHT; GVBD = 59.5%), and tert-butyl hydroperoxide (TBHP; GVBD = 60.0%). Other antioxidants that produced lower but significant (P < 0.05) inhibition of oocyte maturation included propyl gallate (PG; GVBD = 70.3%), 2,4,5-trihydroxybutrophenone (THBP; GVBD = 71.4%), and lauryl gallate (LG; GVBD = 71.4%). Antioxidants that had no effect on oocyte maturation at the same concentration (100 microM) included ascorbic acid, vitamin E, and Trolox. Inhibition of GVBD was evident for up to 8 h of incubation of OCC and denuded oocytes (DO) with BHA or NDGA and was reversed by washing. NDGA was less potent than BHA for inhibition of GVBD in DO, unlike that seen with OCC. Oocyte maturation was induced by incubation of follicles for 3 h with human chorionic gonadotropin (hCG), and this response was inhibited by BHA or NDGA. These findings support the conclusion that cell-permeant antioxidants inhibit spontaneous resumption of meiosis, which may implicate a role of oxygen radicals in oocyte maturation.

Cytotoxic effects of NSL-1406, a new thienopyrimidine derivative, on leukocytes and osteoclasts

We synthesized a series of thienopyrimidine derivatives and examined their cytotoxic effects on several cell lines. One of the derivatives, NSL-1406, was shown to exert potent cytotoxic effects on leukemia cell line including P388 cells and J774 cells. It was also inhibitory on mouse osteoclasts and suppressed the in vitro bone resorption by osteoclasts at nanomolar concentrations.

Percutaneous microwave hepatic tumor coagulation with segmental hepatic blood flow occlusion in seven patients

OBJECTIVE

We assess the usefulness of microwave hepatic tumor coagulation therapy with balloon occlusion of segmental hepatic blood flow for eight recurrent metastatic hepatic tumors in seven patients.

CONCLUSION

Limited early experience with microwave hepatic tumor coagulation therapy and segmental hepatic blood flow occlusion has been positive, suggesting that further clinical evaluation is warranted.

Effect of DP-1904, a thromboxane synthetase inhibitor, on antigen- and spasmogen-induced bronchoconstriction in rodents

The effect of DP-1904 [6-(1-imidazolylmethyl)-5,6,7,8-tetra-hydronaphthalene-2-car boxylic acid hydrochloride], a selective thromboxane synthetase inhibitor, was examined on antigen- and spasmogen-induced bronchoconstriction in rodents. Oral administration of DP-1904 (1, 3, 10 mg/kg) as well as OKY-046 (sodium (E)-3[4-(1-imidazolylmethyl)-phenyl]-2-propanoate, 100 mg/kg), significantly inhibited immunoglobulin G-mediated bronchoconstriction in actively sensitized guinea pigs. Immunoglobulin E-mediated bronchoconstriction in actively sensitized rats was also inhibited by both DP-1904 (1, 10 mg/kg) and OKY-046 (100 mg/kg). DP-1904 (3-30 mg/kg) and OKY-046 (30 mg/kg) suppressed leukotriene D4-induced bronchoconstriction in guinea pigs. In these models, the endogenous levels of thromboxanes significantly increased following the stimulus (antigen and leukotriene D4). DP-1904 (10 mg/kg) inhibited the increase in thromboxane level in both plasma and bronchial alveolar lavage fluid. These actions of DP-1904 persisted for more than 12 h, indicating a long-lasting effect of DP-1904 on bronchoconstriction. The results showed that the biological activity of DP-1904 in our rodents models is more potent than that of OKY-046 (Ozagrel), which is available as an anti-asthma agent in Japan.

A possible involvement of thromboxane A2 and peptide leukotrienes in hyperresponsiveness of Sephadex-treated rat lung parenchyma

An augmented contraction and elevated thromboxane (TX) B2 release were observed, when the isolated parenchyma from Sephadex-treated rats was stimulated by 5-hydroxytryptamine (5-HT). Release of peptide leukotrienes (pLTs) was also increased by the stimuli. In the Sephadex-induced hyperresponsiveness model, DP-1904, a novel TX synthetase inhibitor, at the concentrations of 3 x 10(-7) to approximately 3 x 10(-6) M, reduced the augmented contraction. Also, indomethacin (3 x 10(-6) M), a histamine H1 antagonist and AA-2414 (10(-6) M, a TXA2 antagonist, significantly attenuated the hyperresponsiveness to 5-HT. ICI-198,615 (10(-7) M), a leukotriene receptor antagonist, partially but significantly reduced the augmented contraction. In an ex vivo study, oral DP-1904 significantly inhibited both the augmented contraction and elevated TXB2 release from Sephadex-treated rat parenchyma, but did not affect the blood eosinophilia induced by Sephadex-treatment. These results suggested that the ability to synthesize newly generated lipid mediators such as TXA2 and pLTs to exogenous 5-HT was altered upward by Sephadex injection, and so could lead to augmented contraction of established hyperresponsiveness in rats.

Effects of DP-1904, a thromboxane synthetase inhibitor, on the antigen-induced airway hyperresponsiveness and infiltration of inflammatory cells in guinea-pigs

The effect of DP-1904, a novel thromboxane (TX) synthetase inhibitor, on airway hyperresponsiveness was studied in actively sensitized guinea-pigs. Airway hyperresponsiveness to intravenous ACh was observed at 3 and 7 h after aerosolized antigen challenge. In the model, a significant correlation between increases of respiratory resistance and microvascular leakage was observed, corresponding to the elevation of TXB2 in bronchoalveolar lavage fluid (BALF) in the early phase. DP-1904, at doses of 3 mg/kg or higher given orally one hour prior to the antigen challenge, inhibited the TXB2 production and the development of airway hyperresponsiveness in the early phase. Further, DP-1904 significantly suppressed the accumulation of lymphocytes in BALF and airway hyperresponsiveness in the late phase, although it only slightly decreased the mobilization of eosinophils and neutrophils. The results suggest that TXA2 is possibly involved in the development of airway hyperresponsiveness, and DP-1904 prevented the airway hyperresponsiveness via inhibition of TXA2 production and regulation of inflammatory cells.

Anatomically guided radiofrequency catheter ablation of atrial reentrant tachycardia

Atrial reentrant tachycardia (ART) was ablated in an anatomically guided approach. Five patients with ART underwent 2 linear incisions without careful pace or activation mapping. One line was from an atrial activation site earlier than P wave onset to the nearest fixed anatomic conduction barrier, i.e., the inferior vena cava or coronary sinus ostium. The other line was made just above or closely crossed the first line vertically. Mean application time was 29 +/- 19 minutes, and the application energy was 14,001 +/- 12,322 joules. Mean follow-up after ablation was 15 +/- 10 months. Three patients underwent electrophysiologic study three months after and sustained ART was not induced. All patients were free of sustained tachycardia events without antiarrhythmic drugs during the postoperative clinical course. Although anatomically guided ablation for ART requires much time and energy, it is easily and effectively done without careful activation or pace mapping, and is indicated if ablation using activation mapping or entrainment technique fails to cure the ART.

In vitro effect of DP-1904, a novel anti-asthma agent, against antigen-induced constriction and TXB2 release from the isolated guinea-pig lung parenchymal tissue

The contractile activity and mobilisation of arachidonic acid metabolites in response to the antigen challenge were studied in isolated lung parenchymal tissue from the actively sensitised guinea pig. The sustained constriction of the lung tissue was evoked by the antigen, associated with significant liberation of TXB2, histamine and p-LTs. Other prostanoids (PGF2 alpha, PGD2, PGE2 and 6-keto-PGF1 alpha) were also released by the antigen challenge. DP-1904, an inhibitor of TX synthetase, significantly suppressed the late phase of the antigen-induced constriction. DP-1904 was potent to inhibit the production of TXB2, while DP-1904 accelerated the formation of PGF2 alpha, PGE2 and 6-keto-PGF1 alpha, presumably indicating the alternative changes of dilatory metabolites to the spasmogenic component. Mepyramine and FPL-77512 augmented the effect of DP-1904. AA-861 inhibited the antigen-induced constriction of the lung parenchymal tissue by inhibiting the release of p-LTs and TXB2. Pretreatment of the lung parenchymes with anti-guinea pig platelet serum, in order to deplete the platelets, did not affect the generation of TXB2 both in resting and also in the antigen-stimulated status, indicating that TXA2 is produced in the topical pulmonary tissue. It is concluded that DP-1904 inhibits the parenchymal contraction through potent inhibition of TXA2 generation, associated with significant elevation in PGE2 and PGI2.

Correlative alteration of thromboxane A2 with antigen-induced bronchoconstriction and the role of platelets as a source of TXA2 synthesis in guinea pigs: effect of DP-1904, an inhibitor of thromboxane synthetase

A marked and sustained bronchoconstriction after antigen challenge was produced in actively sensitised guinea pigs, and correlated with increments of thromboxane (TX) A2 level in both the plasma and bronchoalveolar lavage fluid. DP-1904 given orally relieved the bronchoconstriction and increase in TXA2 in a dose-dependent manner. In platelet-depleted animals, antigen-induced bronchoconstriction and TXA2 release in the plasma were significantly reduced compared to those of non-platelet-depleted animals, indicating that platelets are a major cell source of TXA2 production, the remainder originating from the other cells excluding platelets. In the platelet-deprived animal, DP-1904 showed further significant inhibition of the constriction and plasma TXA2 level, and therefore likely inhibits TXA2 synthesis of various cells, including platelets, in the bloodstream. The results suggested that TXA2 is an important mediator responsible for producing antigen-induced bronchoconstriction, and endogenously originated from various cells including platelets in guinea pigs.

[Correlation between pyrimidine nucleoside phosphorylase (PyNPase)/platelet-derived endothelial cell growth factor and histological prognostic factor, and influences of 5'-deoxy-5-fluorouridine (5'-DFUR) administration on PyNPase levels. 5'-DFUR Joint Research Group in the Osaka Area for Gastric Cancer]

PURPOSE

Pyrimidine nucleoside phosphorylase (PyNPase), among which thymidine phosphorylase (dThdPase) exists mainly in human tumor tissues, is an enzyme to convert 5'-deoxy-5-fluorouridine (5'-DFUR) to 5-fluorouracil. Recently, it was reported that dThdPase was identical to platelet-derived endothelial cell growth factor, angiogenetic factor. Therefore, we expect that there is possibility of dThdPase being a prognostic factor.

METHODS

We investigated for a possible correlation between PyNPase activities in tumor tissues and prognostic factors of histological findings, examined the influences of preoperative oral 5'-DFUR administration to PyNPase levels and investigated for a correlation between HPLC methods and ELISA methods in patients with gastric cancer.

RESULTS

Higher levels of PyNPase were observed in patients with advanced t,n,v, and ly factors. PyNPase levels decreased by 5'-DFUR in patients with differentiated cases. A high correlation was found between HPLC and ELISA methods.

CONCLUSION

This study suggests that we must investigate possibility of PyNPase being a prognostic factor in more detail.