[Resection of a metastatic left ventricular tumor with an aid of thoracoscopy].

A 61-year-old woman who complained of chest pain and cough was admitted to our hospital. She was diagnosed with multiple metastasis of breast or lung cancer, and a cardiac tumor was detected by echocardiography during chemotherapy. The tumor was located on the papillary muscle near the apex, had a smooth surface, and was well mobile. Emergency operation was performed because the tumor was considered to be a cause of cerebral infarction. Under cardiopulmonary bypass, resection of the tumor was performed by trans-mitral-valve approach. By using a thoracoscope, we could share information and obtain the details of the tumor during the operation. Resection using a trans-mitral-valve approach with an aid of thoracoscopy is considered useful.

Effect of CYP2D6 polymorphism on pharmacokinetics of a novel ACAT inhibitor, pactimibe and its unique metabolite, R-125528.

PURPOSE: Pactimibe is a novel ACAT inhibitor. The pharmacokinetics of pactimibe and its pharmacologically inactive plasma metabolite, R-125528, of which the main clearance pathway is CYP2D6, was affected by coadministration of quinidine. The aim of this study was to investigate the influence of CYP2D6 polymorphism on pharmacokinetics of pactimibe and R-125528. In addition, exposure was examined after multiple doses of pactimibe sulfate in CYP2D6 poor metabolizer (PMs). METHODS: 24 healthy male Caucasian volunteers, genotyped as extensive, intermediate, and poor metabolizers, were received single dose of 25 mg pactimibe. In a multiple-dose study, six CYP2D6 PMs received 100 mg pactimibe for 21 days and exposure of pactimibe and R-125528 was examined. RESULTS: In contrast to the mild 1.7-fold increase in AUC0-inf of pactimibe, a marked 3.1-fold increase in AUC0-tz of R-125528 was observed in CYP2D6 PMs. After multiple doses of 100 mg pactimibe to CYP2D6 PMs, the accumulation ratio of R-125528 reached 8.8-fold, however, the exposure of R-125528 in CYP2D6 PMs was covered by the exposure in additional metabolite safety testing. CONCLUSIONS: Although CYP2D6 polymorphism greatly affected the pharmacokinetics of R-125528 rather than pactimibe, the exposure in CYP2D6 PMs after a multiple dose of 100 mg pactimibe sulfate was covered by additional non-clinical metabolite safety testing. The finding is clinically informative with respect to the safety testing of drug metabolite present at disproportionately high levels in a special population with specific genetic back ground.

Cloning and characterization of the urea transporter UT3: localization in rat kidney and testis.

Urea transport in the kidney plays an important role in urinary concentration and nitrogen balance. Recently, three types of urea transporters have been cloned, UT1 and UT2 from rat and rabbit kidney and HUT11 from human bone marrow. To elucidate the physiological role of the latter urea transporter, we have isolated the rat homologue (UT3) of HUT11 and studied its distribution of expression and functional characteristics. UT3 cDNA encodes a 384 amino acid residue protein, which has 80% identity to the human HUT11 and 62% identity to rat UT2. Functional expression in Xenopus oocytes induced a large (approximately 50-fold) increase in the uptake of urea compared with water-injected oocytes. The uptake was inhibited by phloretin (0.75 mM) and pCMBS (0.5 mM) (55 and 32% inhibition, respectively). Northern analysis gave a single band of 3.8 kb in kidney inner and outer medulla, testis, brain, bone marrow, spleen, thymus, and lung. In situ hybridization of rat kidney revealed that UT3 mRNA is expressed in the inner stripe of the outer medulla, inner medulla, the papillary surface epithelium, and the transitional urinary epithelium of urinary tracts. Co-staining experiments using antibody against von Willebrand factor showed that UT3 mRNA in the inner stripe of the outer medulla is expressed in descending vasa recta. These data suggest that UT3 in kidney is involved in counter current exchange between ascending and descending vasa recta, to enhance the cortico-papillary osmolality gradient. In situ hybridization of testis revealed that UT3 is located in Sertoli cells of seminiferous tubules. The signal was only detected in Sertoli cells associated with the early stages of spermatocyte development, suggesting that urea may play a role in spermatogenesis.

Tissue engineering a human phalanx.

A principal purpose of tissue engineering is the augmentation, repair or replacement of diseased or injured human tissue. This study was undertaken to determine whether human biopsies as a cell source could be utilized for successful engineering of human phalanges consisting of both bone and cartilage. This paper reports the use of cadaveric human chondrocytes and periosteum as a model for the development of phalanx constructs. Two factors, osteogenic protein-1 [OP-1/bone morphogenetic protein-7 (BMP7)], alone or combined with insulin-like growth factor (IGF-1), were examined for their potential enhancement of chondrocytes and their secreted extracellular matrices. Design of the study included culture of chondrocytes and periosteum on biodegradable polyglycolic acid (PGA) and poly-l-lactic acid (PLLA)-poly-ε-caprolactone (PCL) scaffolds and subsequent implantation in athymic nu/nu (nude) mice for 5, 20, 40 and 60 weeks. Engineered constructs retrieved from mice were characterized with regard to genotype and phenotype as a function of developmental (implantation) time. Assessments included gross observation, X-ray radiography or microcomputed tomography, histology and gene expression. The resulting data showed that human cell-scaffold constructs could be successfully developed over 60 weeks, despite variability in donor age. Cartilage formation of the distal phalanx models enhanced with both OP-1 and IGF-1 yielded more cells and extracellular matrix (collagen and proteoglycans) than control chondrocytes without added factors. Summary data demonstrated that human distal phalanx models utilizing cadaveric chondrocytes and periosteum were successfully fabricated and OP-1 and OP-1/IGF-1 accelerated construct development and mineralization. The results suggest that similar engineering and transplantation of human autologous tissues in patients are clinically feasible. Copyright © 2016 John Wiley & Sons, Ltd.

Identification of thyroid hormone transporters in humans: different molecules are involved in a tissue-specific manner.

We have recently identified that rat organic anion transporters, polypeptide2 (oatp2) and oatp3, both of which transport thyroid hormones. However, in humans the molecular organization of the organic anion transporters has diverged, and the responsible molecule for thyroid hormone transport has not been clarified, except for human liver-specific transporter (LST-1) identified by us. In this study we isolated and characterized a novel human organic anion transporter, OATP-E from human brain. The isolated complementary DNA encodes a polypeptide of 722 amino acids with 12 transmembrane domains. A rat counterpart, oatp-E, was also identified. Homology analysis and the phylogenetic tree analysis revealed that OATP-E/oatp-E is a subfamily of the organic anion transporter. Human OATP-E transported 3,3',5-triiodo-L-thyronine (K(m), 0.9 microM), thyronine, and rT(3) in a Na(+)-independent manner. Although the clone was isolated from the brain, OATP-E messenger RNA was abundantly expressed in various peripheral tissues. The rat counterpart, oatp-E, also transported 3,3',5-triiodo-L-thyronine. In addition, in this study we revealed that human OATP, which is exclusively expressed in the brain, transported 3,3',5-triiodo-L-thyronine (K(m), 6.5 microM), T(4) (K(m), 8.0 microM), and rT(3). These data suggest that in humans, several different molecules are involved in transporting thyroid hormone: OATP in the brain, LST-1 in the liver, and OATP-E in peripheral tissues.

Immunohistochemical distribution and functional characterization of an organic anion transporting polypeptide 2 (oatp2).

The rabbit polyclonal antibody against rat organic anion transporting polypeptide 2 (oatp2) was raised and immunoaffinity-purified. Western blot analysis for oatp2 detected two bands ( 74 and 76 kDa) in rat brain and a single band (76 kDa) in the liver. By immunohistochemical analysis, the oatp2 immunoreactivity was specifically high at the basolateral membrane of rat hepatocytes. Functionally, the oatp2-expressing oocytes were found to transport dehydroepiandrosterone sulfate, delta1 opioid receptor agonist [D-Pen2,D-Pen5]enkephalin, Leuenkephalin, and biotin significantly, as well as the substrates previously reported. These data reveal the exact distribution of the rat oatp2 at the protein level in the liver, and that oatp2 appears to be involved in the multispecificity of the uptaking substrates in the liver and brain.

Carrier-mediated uptake of pravastatin by rat hepatocytes in primary culture.

The transport mechanism of pravastatin, a new cholesterol-lowering drug, was compared in vitro with rat hepatocyte primary culture and mouse skin fibroblasts (L-cells). The uptake of 14C-labeled pravastatin by cultured hepatocytes was temperature- and dose-dependent. The temperature-dependent uptake as a function of [14C]pravastatin concentration showed saturation kinetics with Km = 32.2 microM and a maximal uptake rate of 68 pmol/mg protein/min. The uptake of pravastatin was inhibited significantly by metabolic inhibitors such as rotenone, oligomycin A, antimycin A, 2,4-dinitrophenol and KCN. Unlabeled pravastatin as well as R-416 and R-195, structural analogues of pravastatin, effectively competed for the hepatic uptake of [14C]pravastatin at 37 degrees. These results indicate that pravastatin is taken up by the liver by an active transport. In contrast, the transport of pravastatin by L-cells was temperature-independent and non-saturable, suggesting that the uptake of pravastatin by L-cells is mediated by passive diffusion. The marked difference in the uptake mechanism of pravastatin between hepatocytes and L-cells may account for a unique feature of this drug in that the uptake and inhibition of cholesterol biosynthesis occur selectively in the liver.

Delivery and cytotoxicity of RS-1541 in St-4 human gastric cancer cells in vitro by the low-density-lipoprotein pathway.

RS-1541 is a 13-O-palmitoyl derivative of rhizoxin, an inhibitor of tubulin polymerization. RS-1541 has been shown to bind preferentially to plasma lipoproteins and to exhibit selective and sustained uptake by tumors in mice. To elucidate a mechanism of RS-1541 cytotoxicity, the cellular uptake and the cytotoxicity of a complex of RS-1541 with human low-density lipoprotein (RS-1541/LDL complex) were investigated in cultured St-4 human gastric cancer cells. Both the cellular uptake and the cytotoxicity of the RS-1541/LDL complex were greater in cells with higher LDL-receptor activities than in control cells. Excess amounts of LDL or 1 microM of monensin, a proton ionophore, significantly inhibited both the uptake and the cytotoxicity of the complex. Chloroquine, an inhibitor of lysosomal enzymes, decreased the intracellular level of rhizoxin liberated from RS-1541 and suppressed the cytotoxicity of the RS-1541/LDL complex. However, a detergent-aided solution of RS-1541 showed very low cellular uptake and cytotoxicity, irrespective of the LDL-receptor activities of these cells. These results demonstrate that the RS-1541/LDL complex is incorporated into the cells via the LDL receptor and that it manifests its cytotoxic activity after forming rhizoxin, the original antitumor agent, in the lysosomes.

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 from Candida cylindracea had RS-1541-enhancing and -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.

Radioiodinated 2'-iodospiperone: a new radioligand for in vivo dopamine receptor study.

In vivo dopamine receptor binding of the newly synthesized ligand, 125I-2'-iodospiperone (125I-2'-ISP), was studied in mouse brain. The highest accumulation was found in the striatum. Analysis of the striatal homogenate showed the 125I-2'-ISP to be metabolically stable. Furthermore, this striatal binding was saturable and displaced only by dopaminergic drugs. On the other hand, the accumulation in the cortex was as low as that of the cerebellum and uneffected by the administration of serotoninergic drugs and dopaminergic drugs; results assessed by macroautoradiographic studies. Thus, the newly synthesized 125I-2'-ISP presented high affinity for dopamine receptors in vivo and therefore, holds great potential for the in vivo dopamine receptor studies, provided 123I becomes readily available.

Hair analysis for drug abuse, Part II. Hair analysis for monitoring of methamphetamine abuse by isotope dilution gas chromatography/mass spectrometry.

Sectional analysis of methamphetamine abuser's hair was performed by using stable-isotope dilution GC/MS method. Drug concentrations of hair shaft cut into 2-cm sections from the root side were compared with the self-reported drug histories of 11 cases and the results of experiments on monkeys. It was found that in nine of the 11 cases, the relationship between the results of sectional analysis and drug histories coincided, but the sectional analyses of two cases were not consistent with self-reported drug history. The difference in drug concentrations between the regions of scalp hair was also investigated. Our study suggests that hair analysis, especially sectional analysis, may be useful in determining past drug history even though it is not exact.

Clinical evaluation of a silicone coated hollow fiber oxygenator.

In this article, the clinical experience with a cardiopulmonary bypass (CPB) using a newly developed hollow fiber oxygenator with an ultra-thin layer of silicone is reported. A comparative study of biocompatibility between the new oxygenator and a heparin coated oxygenator is also described. The CPB was performed with a silicone coated oxygenator, Mera Excelung Binding Prim HPO 15 H-C (Group I, n = 6) or Binding Prim HPO 25 H-C (Group II, n = 10) (Senko Medical Instrument Mfg., Tokyo, Japan). Air could be vented through the silicone coated hollow fibers, and it was easy to prime the circuits. The CPB duration was 101 +/- 37 min and 170 +/- 64 min for Groups I and II, respectively. There were no deaths and no complications from CPB. Partial arterial pressure of O2 levels 60 minutes after the start of CPB were 529 +/- 28 mm Hg and 529 +/- 28 mmHg for Group I and II, respectively. Partial arterial pressure of CO2 levels 60 min after the start of CPB were 36.4 +/- 4.6 mmHg and 39.4 +/- 4.4 mmHg, respectively. Plasma free hemoglobin at 60 min was 33.5 +/- 17.2 mg/ dL and 46.7 +/- 26.1 mg/dL for Groups I and II, respectively. As an evaluation of biocompatibility, the effects of the new oxygenator on platelet activation (GP Ib, IIb/IIIa), coagulation (TAT), fibrinolysis (PIC), and inflammatory response (C3a, granulocyte elastase) were investigated during CPB and comparing to those of the heparin coated oxygenator. There were no significant differences in GP Ib, GP IIb/IIa, TAT, PIC, and granulocyte elastase between the two oxygenators. However, 60 min after the start of CPB, the C3a was significantly lower for the new oxygenator group than for the heparin coated oxygenator group (p < 0.03). The new oxygenator showed good gas transfer, low hemolysis, and good biocompatibility. Because of its durability and good biocompatibility, the new oxygenator was determined to be suitable for prolonged extra corporeal circulation.

High reactivity of [11C]CH3I with thiol group in the synthesis of C-11 labeled radiopharmaceuticals.

High reactivity of [11C]-methyl iodide ([11C]CH3I) with the thiol group was demonstrated with cysteamine and other compounds containing a thiol and another functional groups in each structure. The methylation of the thiol group in cysteamine with [11C]CH3I was very rapid at 0 degree C with no catalyst, and gave a high radiochemical yield and purity without any detectable by-product. Moreover, this reaction was not disturbed by the other functional groups, such as -NH2, -OH and -COOH in the same structure. This S-methylation reaction is very useful for producing a new radiopharmaceutical labeled with the short lived positron emitting nuclide C-11.

Transatrial repair of ventricular septal rupture under preoperative localization by transesophageal echocardiography.

We report about a 71-year-old woman with postinfarction ventricular septal rupture who was successfully treated by the transatrial closure under preoperative localization by transesophageal echocardiography. In an attempt at transatrial repair of the ventricular septal rupture, the most important thing is preoperative localization of the defect in the septum, which is located high and posterior, where it is smooth with relatively few trabeculations and can be readily exposed by retraction of the tricuspid valve.

Disposition and metabolism of pravastatin sodium in rats, dogs and monkeys.

Pravastatin sodium (pravastatin) is a potent inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, and was found to be highly effective in animals and humans, in lowering the plasma cholesterol level by inhibiting cholesterol synthesis selectively in the liver. In the present study the disposition and metabolism of pravastatin was studied in rats, dogs and monkeys using [14C]-labelled compound. The extent of absorption was approximately 70% in rats and 50% in dogs. Tissue distribution examined by both whole-body autoradiography and radioactivity measurement demonstrated that the drug was selectively taken up by the liver, a target organ of the drug, and excreted via bile mainly in unchanged form. Since pravastatin excreted by the bile was reabsorbed, the enterohepatic circulation maintained the presence of unchanged pravastatin in the target organ. The profiles of metabolites were studied in various tissues and excreta and a metabolic pathway of pravastatin was proposed.

Less invasive therapy using endovascular stent graft repair and video-assisted thoracoscopic surgery for ruptured acute aortic dissection.

We report a 75-year-old man with a ruptured acute thoracic aortic dissecting hematoma treated using endovascular stent grafting and video-assisted thoracoscopic surgery. This less invasive therapy is a good therapeutic option even in ruptured acute aortic dissections, particularly given the difficulty of surgery.

[Selection criterion of limited operation for lung cancer as a radical operation].

We reviewed partial resection and segmentectomy for 75 cases (6.5%) out of 1,212 cases treated surgically for primary lung cancer between 1957 and 1996. The surgical results of limited operation in radicality group and risk group was comparable to that of standard operation for the stage I lung cancer. Five-year survival of clinical stage I non-small cell lung cancer patients that tumor size is 2.0 cm or less was excellent (88.9%). Although risk group may be the best candidates for limited surgery, careful patient selection and theoretical operative procedure could make limited operation a standard procedure in radicality group.

[Treatments for T4 advanced lung cancer with invasion to the superior vena cava].

We discussed on the treatments for T4 lung cancer with invasion to the superior vena cava, whose prognosis has been poor. However, surgical resection may improve the prognosis compared with radiation therapy. The prosthetic replacement of superior vena cava can be done safely, and its patency is good in cases of ring-enforced ePTFE graft. Although superior vena caval obstruction syndrome had been a hard issue in the advanced cases, stenting in superior vena using the interventional radiological technique is a safe and reliable method. We should consider the stenting as the first choice for superior vena cava obstruction syndrome, because it makes the QOL improve so much.

[The effects of intravenous milrinone for the patient undergoing CABG].

The hemodynamic effects of intravenous infusion of milrinone were evaluated in 25 patients undergoing CABG using an internal mammary artery graft. Milrinone was administered to 9 patients at the time of weaning from cardiopulmonary bypass, at a dosage of 3 to 5 micrograms/kg/min. Postoperative cardiac function was compared in this group versus the other 17 patients who were treated without milrinone. We determined such parameters as cardiac index, wedge pressure and mean pulmonary pressure. Our findings did not show any significant difference between the 2 groups. We also studied a subject of low-output patients (EF < 0.5). In the patients with low-cardiac output, the use of milrinone in addition to standard postoperative administration of low-dose dopamine reduced mean pulmonary pressure and wedge pressure. Thus, milrinone not only improved the left ventricular function, but also expanded the pulmonary vascular bed.

[Results of surgical treatment for pT3 primary lung cancer].

We reviewed pT3 lung cancer for 86 cases (13.1%) out of 659 cases treated surgically for primary lung cancer between 1985 and march 1998. Five-year and ten-year survival rates for all pT3 cases were 48% and 40% respectively and those for pT3N0M0 cases were 67.2%. The operative mortality between 1990 and 1998 (2.4%) was better than that between 1985 and 1989 (6.7%). The extensive resection for pT3 lung cancer was evaluated to be appropriate. However, the prognosis of the patients who underwent combined resection of mediastinal pleura, pericardium or diaphragm was very poor. Five-year survival rate was significantly worse in patients with N2 disease (17.3%) than in patients with N0 disease (65.8%) (p < 0.05). Although the surgical indication for the patients with mediastinal pleura, pericardium or diaphragm disease and N2 disease is still controversial, there is not the extensive surgical indication.