Influence of ETR-p1/f1 antisense peptide on endothelin-induced constriction in rat renal arcuate arteries

1. This study set out to examine the endothelin receptor subtypes mediating vasoconstriction in the rat renal arcuate artery. This was done in isolated vessels 120–200 μm in diameter, incubated with a selective agonist and the novel ‘antisense'' peptide to part of the human endothelin_A receptor.
2. Groups of vessels (n=6) were incubated with increasing concentrations of endothelin-1 (ET-1), from 1 to 100 nM, which caused a 65% maximal contraction at the highest dose with an pEC₅₀ of 8.16±0.11 M. By contrast, in six other vessels sarafotoxin 6c over the same dose range gave a minimal contraction (around 5% of maximum).
3. Preincubation of six vessels with the antisense peptide ETR p₁/f1 at 1 μM had no effect on the ET-1 induced vasoconstriction, in terms of displacement of the concentration-response curve or the maximal tension achieved by the agonist. In the six vessels exposed to 4 μM ETR p₁/f1, there was a significant shift of the concentration-response curve and a lower pEC₅₀ at 7.78±0.09 M (P<0.05). At the highest concentrations of ETR p₁/f1, there was a marked suppression of all responses to ET-1, which at the maximal concentrations tested, 0.1 μM, only reached some 10% of the maximal achievable contraction.
4. Increasing ET-1 concentrations up to 2 μM in vessels incubated with 40 μM ETR-p₁/f1 showed that the blockade could be overcome and that the relationship was shifted to the right (P<0.001) by approximately one log unit with a pEC₅₀ of 7.13±0.11 M. A Schild plot of the data indicated the antagonist to be acting competitively at a single population of receptors.
5. At the highest concentrations tested, 40 μM, ETR-p₁/f1 had no effect on noradrenaline-induced contractions, indicating a lack of non-specific actions.
6. Together, these data suggest that at the rat renal arcuate artery the endothelin_A receptor is the predominant functional receptor mediating contraction. Furthermore, this study has shown the potential usefulness of this novel type of ‘antisense'' peptide in blocking receptor activation.

     

Intracellular activation and cytotoxic action of RS-1541 against cultured human tumor cells

RS-1541, an acyl-derivative of rhizoxin (Fig. 1), is a potent antitumor compound. This agent showed cytotoxicity in vitro on some cultured human tumor cells, although it was less potent than rhizoxin. Rhizoxin exhibited antitumor effects by inhibiting the polymerization of tubulin, whereas RS-1541 did not inhibit tubulin polymerization in vitro. However, cell cycle analysis in vivo showed that the two agents had the same mode of action. The cytotoxicity of RS-1541 was enhanced when the initial cell density of the cells was increased. The cytotoxicity was also enhanced when the membrane fraction of St-4 cells, which were the most sensitive to RS-1541 among the cell lines tested, was added to the target cells. When St-4 cells were incubated with [¹⁴C]-RS-1541, significant amounts of [¹⁴C]-rhizoxin were produced within the cells. Further fractionation of the crude membrane showed that the activity that enhanced the cytotoxicity of RS-1541 (RS-1541-enhancing activity) belonged to the mitochondrial-lysosomal fraction, not to the microsomal fraction. Both the enhancing activity and the activity that converting [¹⁴C]-RS-1541 to [¹⁴C]-rhizoxin (RS-1541-converting activity) were inhibited by treatment with chloroquine, an inhibitor of lysosomal function. Cholesterol esterase derived fromCandida cylindracea had RS-1541-enhancingand-converting activities. These data suggest that RS-1541 exerts its cytotoxic action after being converted to rhizoxin within the cells by a lysosomal enzyme such as cholesterol esterase.Abbreviations DMSO Dimethylsulfoxide - PBS(-) Ca²⁺ Mg²⁺-free phosphate-buffered saline - HCO60 hydrogenated castor oil polyethylene glycor ether - DMA dimethylacetamide - RSB reticulocyte standard buffer, consisting of 10mM NaCl, 1.5 mM MgCl₂, and 10 mM TRIS-HCl, (pH 7.4) - TLC thin-layer chromatography - ara-C 1--D-arabinofuranosylcytosine - LDL low-density lipoprotein     

Contribution of peripheral chemoreception to the depression of the hypoxic ventilatory response during halothane anesthesia in cats

BACKGROUND: The effects of inhalational anesthetics on the hypoxic ventilatory response are complex. This study was designed to determine the contribution of peripheral chemoreception to the depression of hypoxic ventilatory response seen with halothane anesthesia. METHODS: Cats were anesthetized with pentobarbital sodium and alpha-chloralose and artificially ventilated. Respiratory output was evaluated by phasic inspiratory activity of the phrenic nerve. In 12 cats, this activity was measured during inhalation of an hypoxic gas mixture with halothane, 0, 0.1, and 0.8%, with intact or denervated carotid bodies. In 10 cats, a carotid body was isolated from the systemic circulation and perfused with hypoxic Krebs-Ringer solution equilibrated with halothane, 0, 0.1, and 0.8%. RESULTS: The hypoxic ventilatory response was depressed in a dose-dependent manner during halothane anesthesia. In carotid body perfusion studies, the response was significantly depressed only with halothane, 0.80%. CONCLUSION: The hypoxic ventilatory response is depressed by a high dose of halothane through a peripheral effect at the carotid body.     

REP-1 gene mutations in Japanese patients with choroideremia

· Background: Choroideremia (CHM) is an X-linked progressive dystrophy of the choroid, retinal pigment epithelium, and retina. Recently, the REP-1 gene was isolated and the causative mutations in the gene were detected in patients with CHM. In a previous study, we described a Japanese family with CHM who had a mutation in the REP-1 gene. In the present study, we performed extensive analysis of the REP-1 gene in patients with CHM from several institutions in Japan. · Methods: Twenty-six patients with CHM and 5 unaffected females from 22 independently ascertained families were examined. Exons 1–15 of the REP-1 gene were screened by single-strand conformation polymorphism. The DNA fragments suspected of any variations were directly sequenced. · Results: Fifteen different mutations, including one previously reported mutation, were detected in 18 families. In addition, carrier status was proven in four unaffected females found to be heterozygous for the mutant allele. · Conclusions: Fifteen different mutations of the REP-1 gene were detected in 18 Japanese families. There were no hot spots for the mutations and no missense mutations. The results show that REP-1 gene defects cause CHM in Japanese patients, and the mutations in these Japanese patients differed from the mutations reported for CHM patients in Europe, Canada, and America except for R267X and 1313delTC. These findings suggest that the mutations occurred independently in the Japanese patients. Received: 13 August 1998 Revised version received: 16 November 1998 Accepted: 9 December 1998     

Use of ultrasound-guided percutaneous needle biopsy in the diagnosis of mediastinal tumors

We herein report the usefulness of ultrasoundguided percutaneous needle biopsy for histological diagnosis in 18 patients with mediastinal tumors. Computed tomography revealed these tumors to be in contact with the chest wall. The preoperative diagnosis was thymoma in 7 patients, germinoma in 5, neurogenic tumor in 3, and other in 3. The most commonly encountered indication for an ultrasound-guided percutaneous needle biopsy was an anterior mediastinal lesion (78%; 14 of 18 patients). In 16 (89%) of the 18 patients, the biopsy diagnosis corresponded to the post-operative diagnosis. No complications were encountered in any of the patients. This new technique of ultrasound-guided percutaneous needle biopsy is both relatively simple and highly accurate and may thus be useful for outpatients. Preoperative ultrasound-guided percutaneous needle biopsy is thus considered to be a safe and reliable method for the histological diagnosis of mediastinal tumors, and a good alternative to traditional biopsy techniques such as mediastinoscopy or thoracotomy.Presented at the 11th Biennial Asian Congress on Thoracic and Cardiovascular Surgery, Kuala Lumpur, Malaysia, November, 21–25, 1993.     

Alumina versus polyethylene in total knee arthroplasty.

The cementless alumina total knee prosthesis, which uses alumina in the portions coming in contact with the bone and a combination of alumina and ultra-high molecular-weight polyethylene (UHMWPE) in the sliding portions, is referred to as a total condylar. Alumina total knee arthroplasty was performed on 137 patients, including 103 rheumatoid arthritis (RA) and 34 osteoarthrosis (OA) patients, from January 1982 to February 1985. The follow-up period was seven years 11 months and four years ten months, respectively. At follow-up evaluation, 108 patients were available for clinical and roentgenographic examinations, amounting to a 79% follow-up rate. At follow-up examination, 67 joints (62%) were completely pain free and 28 joints (26%) caused slight pain on bearing weight. Walking ability was recovered moderately in RA and markedly in OA. In RA, 14 of 84 knees were cemented and one knee was treated with loosening. Of 72 cementless implantations, 55 sustained displacing distally and one sustained loosening in the tibia, whereas 31 sustained displacing proximally and six sustained loosening in the femur. In OA, 21 cementless knees had 17 displacings in the tibia, and ten displacings and two loosenings in the femur. Scanning electron microscopy (SEM) observation of the UHMWPE surface in tibial plates revealed smoothing and burnishing. Alumina is far superior to metal for the sliding part, although it is not always best for the portion in contact with the bone. To resolve these problems, for cementless fixation, anchoring portions of Ti alloy and alumina implants were covered with beads and coated with hydroxyapatite. For cement fixation, "the interface bioactive bone cement technique" interposing hydroxyapatite granules between bone and cement was performed.     

Acute toxicity,percutaneous absorption and effects on hepatic mixed function oxidase activities of 2,4,4′-trichloro-2′-hydroxydiphenyl ether (Irgasan® DP300) and its chlorinated derivatives

Acute toxicity of 2,4,4-trichloro-2-hydroxydiphenyl ether (Irgasan^® DP300) (I) and its three chlorinated derivatives, 2,3,4,4-tetrachloro-2-hydroxydiphenyl ether (II), 2,4,4,5-tetrachloro-2-hydroxydiphenyl ether (III) and 2,3,4,4,5-pentachloro-2-hydroxydiphenyl ether (IV), in mice were examined by intraperitoneal injection. The LD₅₀ values of Irgasan DP300, II, III and IV were 1,090, 710, 650 and 430 mg/kg, respectively.The percutaneous absorptions of these tritiated compounds were also examined by the application on the backs of mice. The radioactivities in most tissues reached to the maximal levels at 12 h or 18 h after dosing, which corresponded to 11–76% of the maximal levels given by the oral administration (Kanetoshi et al. 1988a). These results show the high percutaneous absorbability of Irgasan DP300 and its chlorinated derivatives.The intraperitoneal administrations of III and IV to rats induced hepatic microsomal aminopyrine N-demethylase and aniline 4-hydroxylase activities similarly to phenobarbital. These chlorinated derivatives also increased cytochrome P-450 content, and the activities of aminopyrine N-demethylase and N-methylaniline N-demethylase in hepatic microsomes from mice. The extents of the increases were similar to those by phenobarbital and 3-methylcholanthrene.     

Hyperthermo-chemotherapy combined with cytoreductive surgery for the treatment of gastric cancer with peritoneal dissemination

Continuous hyperthermic peritoneal perfusion (CHPP) with anticancer agents (mitomycin C and cisplatin) in warm saline was performed in patients with peritoneal dissemination of gastric cancer following resection of the primary lesion. The effect of CHPP was examined by a second-look operation. This study includes 41 cases of gastric cancer with peritoneal dissemination but without liver metastasis treated during the past 6 years. The overall median survival was 14.6 months to 64.2 months from CHPP to death and the 3-year survival rate was 28.5%. Second look surgery revealed a remarkable diminution in the degree of peritoneal dissemination in 7 (50%) of 14 patients with disappearance of ascites after only one course of CHPP in 7 (77.8%) of 9 patients. Long-term 3 year-survival was noted in 4 (9.8%) patients on CHPP. Side effects were renal insufficiency in 2 (5%) patients, leukopenia in 2 (5%) patients, and perforation of the small intestine in 1 (2%) patient. These results suggest the effectiveness of CHPP in the treatment of gastric cancer with peritoneal dissemination.

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Resumen La perfusión hipertérmica continua (PHTC) con agentes anticancerosos (mitocina G y cisplatino) y solutión salina fue realizada en pacientes con cáncer gástrico con diseminación peritoneal después de resección de la lesión primaria, y el efecto de PHTC fue determinado mediante reexploración (operación de second look, OSL). La población de pacientes está constituída por 41 casos de cáncer gástrico con diseminación peritoneal pero sin metástasis hepáticas, tratdos en el curso de los últimos 6 años. La sobrevida media global fue de 437 dias (rango 28 a 1925 días) desde la PHTC hasta la muerte y la tasa de sobrevida a 3 años fue 28.5%. La OSL reveló una notoria disminución de la diseminación peritoneal en 7 (50%) de 14 casos y desaparición de la ascites después de sólo un ciclo de PHTC en 7 de 9 casos con ascitis. Sobrevida de 3 años ocurrió en 4 casos. Los efectos colaterales fueron insuficiencia renal en 2 casos (5%), leucopenia en 2 casos (5%) y perforación del intestino delgado en 1 caso (2%). Los anteriores resultados sugieren que la PHTC es eficaz en el tratamiento del cáncer gástrico con diseminación peritoneal.

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Résumé La perfusion péritonéale continue hyperthermique (PPCH) avec des agents anticancéreux comme le mitomycine C et la cis-platine avec sérum physiologique chauffé a été instaurée lorsqu'une carcinose d'origine gastrique a été trouvée. Les effets de la PCH ont été évalués chez 16 patients lors d'un second-look (SL). Cette étude concerne 41 patients avec carcinose péritonéale sans métastase hépatique observés au cours des 6 dernières années. La survie globale médiane était de 437 jours (extrêmes 28 à 1925 jours): le taux de survie a 3 ans était de 28.5%. Les lésions avaient diminué de façon notable chez 7 (50%) de 14 patients. L'ascite a disparu dans 7 des 9 cas. Une survie à long terme (3 ans) a été notée dans 4 cas. Les effets secondaires ont été une insuffisance rénale dans 2 cas (5%), une leucopénie dans 2 cas (5%) et une perforation de l'intestin grêle dans un cas (2%). Les résultats suggèrent que la PPCH est efficace dans le traitement du cancer gastrique avec dissémination péritonéale.

     

The endoscopic evaluation of gastritis,gastric remnant residue,and the incidence of secondary cancer after pylorus-preserving and transverse gastrectomies

Background Pylorus-preserving gastrectomy (PPG) and transverse gastrectomy (TrG) have been accepted as function-preserving procedures for node-negative early gastric cancer. It is believed that a better quality of life is guaranteed after PPG or TrG compared to that after distal subtotal gastrectomy (DSG) with Billroth type-I reconstruction. However, objective evaluations of the gastric remnant following gastrectomy have not been widely reported, and the real advantages and disadvantages of PPG or TrG over DSG remain unclear. Moreover, the risk of secondary cancer after PPG or TrG is uncertain.Methods Between 1991 and 2000, 834 DSGs were carried out in our institute for preoperatively diagnosed patients with early gastric cancer. The degree of residual gastritis and the amount of diet residue in the gastric remnant were evaluated by annual gastrointestinal endoscopic investigations prospectively for 72 patients after PPG, 95 patients after TrG, and 60 patients after DSG. These analyses were performed using the RGB classification (residue, gastritis, bile). The incidence of disease greater than or equal to grade 2 was calculated, and the time trends of the incidence for each procedure were also studied for 3 years after gastrectomy. In addition, secondary cancer cases in the gastric remnant mucosa were checked for each procedure during this period, and the incidence of secondary cancer after each operation was calculated.Results The incidence of gastritis, of grade 2 or more, found in the gastric remnant was significantly lower after PPG (1.4%) and TrG (2.1%) than after DSG (43.3%). However, the incidence of moderate or greater residue in the gastric remnant, grade 2 or more, was significantly higher after PPG (45.8%) and TrG (40.0%) than after DSG (11.7%). The analysis of time trends of gastritis and diet residue reflected the significant advantage or disadvantage for each procedure 1 year after surgery. The analysis also included these factors without consideration of elapsed time following surgery. Two patients after PPG (2.8%) and three patients after TrG (3.2%) developed secondary cancer in the gastric remnant. No DSG-treated patient showed new cancer genesis in the remaining stomach.Conclusion PPG and TrG have the advantage over DSG in preventing postoperative gastritis in the gastric remnant. On the other hand, moderate or greater diet residue in the gastric remnant is more common after PPG or TrG than after DSG. For the risk of carcinogenesis in the remnant gastric mucosa, we could not conclude that there was any apparent difference between these range-limited gastrectomies and conventional DSG. Further study is necessary to determine the significant advantages and disadvantages of using PPG or TrG.     

Transitional cell carcinoma of the ovary: Report of three cases

Background We investigated retrospectively the records and tissue samples of patients with primary ovarian transitional cell carcinoma to determine clinical and pathologic features. Methods The records of 3 patients with ovarian transitional cell carcinoma were reviewed using data from several imaging techniques: transvaginal ultrasound, computed tomography, and magnetic resonance imaging. We also determined levels of several tumor marker molecules; and the level of carbohydrate antigen 125 (CA 125), was examined by means of immunohistochemistry. Results The tumors of 2 patients were classified as pure trnasitional cell carcinoma; in the remaining patient, as predominantly transitional cell carcinoma. All tumors were bilateral, and 2 of the 3 tumors formed solid masses. Areas of irregular high intensity signals were seen in magnetic resonance images of the solid parts of the tumors. All 3 tumors tested positive for CA 125; histochemical expression was confined to the tumor cell membrane and/or the cytoplasm in all cases. The tumors of all 3 patients tested negative for carcinoembryonic antigen (CEA), and second-look laparotomies did not reveal any residual neoplasms in any of the patients. The patients have been in a disease-free state for 34, 42, and 14 months, respectively. Conclusion Our results suggest that transitional cell carcinomas tend to arise bilaterally and to form solid tumors. Magnetic resonance imaging was a useful diagnostic modality in these cases. Transitional cell carcinoma was characterized by the presence of CA 125 and the absence of CEA.