[Surgical treatment of aortic stenosis with polycythemia vera: a case report]

We report a case of 67-year-old woman with severe aortic stenosis complicated by polycythemia vera (PV). She has been treated for PV with busulfan over the past three years. On admission, she had increase in white blood cell, red blood cell and platelet count. The pressure gradient between left ventricle and aorta was 170 mmHg. Aortic valve was bicuspid and replaced with a 21 mm Carpentier-Edwards pericardial xenoprosthesis. Ascending aorta with a diameter 6.0 cm was replaced simultaneously with a 30 mm Dacron graft (Hemashield). Post-CPB course was uneventful except for a tendency to the prolongation of activated clotting time. She was discharged from the hospital in good condition.

Interaction between polyanions and cell nuclei: mechanism of gelatination of nuclei

We investigated the mechanism by which polyanions gelatinized nuclei of some mouse lymphocytes and ruptured these cells. The gel produced by the addition of dextran sulfate (DS) to mouse lymphocyte nuclei was composed of histones (H1, H2A, H2B, H3, and H4), DS, and DNA. Adding DS to the chromatin obtained from nuclei by micrococcal nuclease (MNase) digestion also produced a gel containing a complex of DS-histones-DNA. When this mixture was further digested by MNase, DNA debris of random sizes was observed instead of the 150-bp repeating units of DNA usually observed when normal nucleosomes are digested with MNase. Removal of DS from the chromatin-DS gel resulted in the regeneration of nucleosomes. These results suggest the following: After entering the cells with damaged cellular membrane, DS extracts histones from nucleosomes to form DS-histone complexes, which then aggregate with the liberated DNA to form a macromolecular gel. Finally, the swelling pressure of the gel destroys the cells.

Partial cardiopulmonary bypass in rats for evaluating ischemia-reperfusion injury

The authors developed a miniaturized partial cardiopulmonary bypass model in rats by using membrane oxygenators. Sprague-Dawley rats underwent general anesthesia and tracheostomy for ventilation. Partial cardiopulmonary bypass was carried out through the jugular cannula (18 gauge) for venous blood drainage and through the femoral arterial cannula (24 gauge) at a flow of 50 ml/kg/min. Membrane oxygenators used in this study maintained arterial oxygen tensions (PaO2) at 300-500 mmHg and carbon dioxide tensions (PaCO2) at 25-35 mmHg, with a gas mixture of 95% O2 + 5% CO2 (n = 7) for at least 2 hr of bypass circulation. To test the feasibility of this system for investigation of ischemia-reperfusion injury, hypoxic challenges with gas mixtures of different oxygen concentrations were examined. After equilibration of the bypass circulation for 1 hr, the following gases were tested for 15 min: Group I, 95% air + 5% CO2 (FiO2 = 0.21, n = 5); Group II, 10% O2 + 5% CO2 + 85% N2 (FiO2 = 0.1, n = 5); and Group III, 95% N2 + 5% CO2 (FiO2 = 0, n = 5). Equilibrated PaO2 values after challenge with these gases for 15 min were as follows: Group I: 89.6 +/- 3.7, Group II: 53.8 +/- 1.4, Group III: 25.6 +/- 2.0 mmHg (p < 0.01 between Groups I and II, I and III, II and III; p < 0.01 vs. prehypoxic PaO2 values in all groups). PaO2 values returned to the previous level within 15 min after return to the standard gas mixture (95% O2 + 5% CO2) supply. This system provided stable cardiopulmonary bypass in rats for at least 2 hr and may be useful for investigation of ischemia-reperfusion injury.

Introducing a point mutation identified in a patient with pituitary resistance to thyroid hormone (Arg 338 to Trp) into other mutant thyroid hormone receptors weakens their dominant negative activities

Clinical resistance to thyroid hormone (RTH) has been classified into generalized resistance to thyroid hormone (GRTH) and pituitary resistance to thyroid hormone (PRTH) types. Since similar mutations have been identified in tri-iodothyronine (T3) receptor (TR) beta gene in GRTH and PRTH, and since considerable overlap has been seen in the clinical manifestations in patients with GRTH and PRTH, two subtypes of RTH are now considered to be a continuous spectrum with the same genetic defect. A point mutation at amino acid Arg 338 to Trp (R338W) which we identified in a patient with PRTH is very interesting, since R338W has been found in several other patients with PRTH, raising the possibility that this mutation may tend to associate with a phenotype of PRTH. In our previous study, we found that R338W had relatively less impaired transcriptional potency, weaker dominant negative activity on various T3 response elements and poor homodimer formation, as compared with another GRTH mutant. In this study, to investigate the functional properties of R338W further, especially in terms of the relation between transcriptional activity and dimer formations, we introduced the R338W mutation into the mutant receptors, K443E and F451X, constructing the double mutants, R338W/K443E and R338W/ F451X. Both R338W/K443E and R338W/F451X showed negligible T3 binding and transcriptional activities. The dominant negative activities of K443E and F451X were, however, significantly weakened by introducing the R338W mutation. As a control, a double mutant G345R/K443E was constructed by introducing a point mutation, G345R, located in the same exon 9 as R338W, into the K443E mutant. Dominant negative activity did not differ between G345R/K443E and K443E. Homodimer formation was significantly reduced in the double mutants containing R338W, but not G345R. In summary, introducing the R338W mutation, but not G345R, into the mutant TR significantly weakened the dominant negative activity, despite further impairment of the T3 binding and transcriptional activities.

Inhibitory guanine nucleotide regulatory protein alpha-subunits in brain of spontaneously hypertensive rats

Previously we have reported a decreased GABAB receptor expression in brain of spontaneously hepertensive rats (SHR). Moreover, decreased receptor numbers were accompanied by depressed stimulation of cAMP formation. We have now quantified Gi alpha protein by immunoblotting in cerebral membranes from 11-week-old normotensive Wistar-Kyoto rats (WKY) and hepertensive SHR. The levels of the alpha-subunit in the two sets of membranes were similar. In conclusion, the reduced response in adenylate cyclase activity to agents that function via the Gi protein, e.g., GABAB receptor agonists, in SHR brain is not a consequence of altered level of Gi alpha protein.

Gene expression and localization of amelogenin in the rat incisor

Gene expression and localization of amelogenin were studied in the developing rat incisor by the methods of in situ hybridization and immunohistochemistry. ISH revealed the first expression of amelogenin mRNA in the inner enamel epithelium of the cervical loop. The signals were clearly observed in pre-ameloblasts in the region bordering on predentin formation and became more intense toward the cells on the initial enamel matrix secretion. The maximal signals were found in the cytoplasm of secretory ameloblasts. From the terminal secretion zone, the signals then became gradually weaker toward the incisal edge but were still evident in the cytoplasm of shortening, transitional ameloblasts and those at the early maturation stage. No signals were found in the cells of the stratum intermedium and stellate reticulum throughout amelogenesis. Immunohistochemistry by means of an antibody against amelogenin C-telopeptide consisting of 12 amino acids revealed immunoreaction in the secretory ameloblasts reacting to the ISH. When a polyclonal antibody against amelogenin was used, immunoreaction was found in the distal ends of ruffle-ended ameloblasts (RA) in the maturation zone. Those results indicated that amelogenin is synthesized by ameloblastic cells from the inner enamel epithelium to the early maturation stage and is then resorbed by the RA.

Potent immunosuppressants, 2-alkyl-2-aminopropane-1,3-diols

Several immunosuppressants, ISP-I [(2S,3R,4R)-(E)-2-amino-3,4-dihydroxy-2-(hydroxymethyl)-14-oxoeicos++ +-6-enoic acid, myriocin = thermozymocidin] and mycestericins A-G, were isolated from culture broths of Isaria sinclairii and Mycelia sterilia, respectively. In order to investigate structure-activity relationships, extensive modifications of ISP-I were conducted, and it was established that the fundamental structure possessing the immunosuppressive activity is a symmetrical 2-alkyl-2-aminopropane-1,3-diol. The tetradecyl, pentadecyl, and hexadecyl derivatives prolonged rat skin allograft survival in the combination of LEW donor and F344 recipient and were more effective than cyclosporin A. Among them, 2-amino-2-tetradecylpropane-1,3-diol hydrochloride, ISP-I-55, showed the lowest toxicity. ISP-I-55 is a promising lead compound for the development of effective immunosuppressants for organ transplantations and for the treatment of autoimmune diseases.

Molecular design of inhibitors of in vitro oriC DNA replication based on the potential to block the ATP binding of DnaA protein

DnaA protein, the initiation factor for chromosomal DNA replication in Escherichia coli, is activated by binding to ATP. We earlier reported that 3-acetoxy-2,2'-bi-1H-indol inhibited the ATP binding to DnaA protein (Sasaki, S., Mizushima, T., Hashimoto, T., Maeda, M., and Sekimizu, K. (1994) Bioorg. Med. Chem. Lett. 4, 1771-1774). In the present study, derivatives of 3-acetoxy-2,2'-bi-1H-indol with different lengths of aliphatic chains at the 3-O position were synthesized, and their potential to inhibit the ATP binding to DnaA protein was examined. Elongation of the aliphatic chain resulted in inhibition of the ATP binding to DnaA protein at lower concentrations. Among the derivatives, 3-[N-(11-carboxyundecyl)]carbamoylmethoxy-2,2'-bi-1H-indol (structure 7 (3-CUCM-BI)) exhibited the most potent inhibition with an IC50 value of 7 microM. The mode of the inhibition was competitive. We further demonstrated that structure 7 (3-CUCM-BI) inhibited DNA replication of the oriC plasmid in a system reconstituted from purified proteins. This inhibition was specific for the initiation of DNA replication rather than for the elongation. The inhibition was overcome by preincubation of DnaA protein with ATP. Furthermore, structure 7 (3-CUCM-BI) showed little inhibition on DNA synthesis in the ABC primosome system. We propose that structure 7 (3-CUCM-BI) functions in the in vitro oriC DNA replication by inhibiting the ATP binding to DnaA protein.

[Two cases of total arch replacement after coronary artery bypass surgery with internal mammary artery graft]

We report two successful cases of total arch replacement after coronary artery bypass surgery (CABG) using internal mammary artery graft (ITA). Case 1 had a true aneurysm of the distal aortic arch occurring 7 years after CABG using left ITA, and case 2 had a dissecting aneurysm of DeBakey II occurring 10 months after CABG using right ITA. This patient was also complicated by a preexisting true aneurysm of the proximal descending aorta. Both cases were managed by repeat midsternal incision, selective cerebral perfusion (SCP) and retrograde cardioplegia. In both cases, functioning ITAs were dissected out easily without injury, and an operative filed for total arch replacement was well obtained under the cardioplegia and brain protection mentioned above.

Polymerase chain reaction-based polymorphisms in the porcine cholecystokinin (CCK) gene and assignment to chromosome 13

Polymorphisms were identified in the porcine cholecystokinin (CCK) gene by digestion of products from polymerase chain reaction (PCR) with the restriction enzyme DpnII. Individuals from the European pig gene mapping project (PiGMaP) consortium reference families (eight full-sib families, 91 total progeny) were genotype to determine linkage relationships between the CCK gene and previously mapped loci. Linkage analysis revealed that the CCK gene is located on porcine chromosome 13.

20-[18F]fluoroarachidonic acid: tissue biodistribution and incorporation into phospholipids

The in vivo behavior of 20-[18F]fluoroarachidonic acid (18F-FAA) was investigated to evaluate its potential use as a radiotracer for studying the regional brain and heart lipid metabolism by positron emission tomography (PET). Tissue biodistribution studies in rats have revealed that 18F-FAA has a high uptake in the liver and lung, thus probably reflecting the metabolism, and is accompanied by both low in vivo defluorination and low blood levels. At 30 min postinjection, the uptake in the brain and heart reached values of 0.26 +/- 0.02 and 1.22 +/- 0.58% dose/g, respectively, with ratios to the blood radioactivity of 1.04 and 4.88, respectively. Lipid extraction at 30 min postinjection showed that 39% of the brain radioactivity was in the organic phase whereas the organic phase from heart tissue contained 73% of the total radioactivity. A TLC analysis demonstrated that 18F-FAA was mainly bound to phospholipids in the brain and heart tissue as expected. Based on the findings of this study, the utility of 18F-FAA as an in vivo tracer for cerebral phospholipid studies appears to be limited because of its relatively high radioactivity in the aqueous brain fraction. However, our findings do suggest that this agent might be useful as a tool for studies of cardiac phospholipid turnover, even though it demonstrated a poor heart-to-lung and heart-to-liver contrast.

[Micro fabricated enzyme battery]

Although various work has been done in the field of implantable micro actuators such as artificial organs and micro surgery robots, a suitable electric power supply for these is yet to be developed. For this purpose a micro fabricated enzyme fuel cell was developed which uses glucose contained in the human body as a fuel. In order to obtain enough voltage each cell was formed as part of a serial array on a silicon wafer. Glucose solution enters the cells by a capillary effect. In this article fuel cells already developed using biocatalysts are described, and the future possibility of a micro fabricated enzyme battery is discussed.

GABAB-ergic stimulation in hypothalamic pressor area induces larger sympathetic and cardiovascular depression in spontaneously hypertensive rats

To determine whether central GABA (gamma-aminobutyric acid) B receptor stimulation would affect the sympathetic and cardiovascular activities, baclofen (a GABAB receptor agonist) was injected into lateral cerebral ventricles (intracerebroventricularly, ICV) in urethane-anesthetized normotensive rats. Intracerebroventricular injections of GABAA agonist (muscimol, 1 microgram) consistently decreased blood pressure and heart rate. In contrast ICV injections of baclofen (2 micrograms) increased blood pressure (BP) and heart rate with initial transient cardiovascular depression, and these effects of baclofen were abolished by ICV pretreatment with GABAB antagonist (saclofen, 100 micrograms). To determine whether the cardiovascular effects of ICV injections were elicited by activating GABA receptors in the hypothalamus, we injected baclofen or muscimol directly into various hypothalamic areas. Baclofen (100 and 800 ng) injected into the ventromedial hypothalamus (VMH) or posterior hypothalamus (PH) of normotensive rats produced dose-related decreases in sympathetic nerve activity, blood pressure, and heart rate. These effects of baclofen were larger in VMH injections than in PH injections. The depressor responses elicited by VMH injections of baclofen were abolished by intravenous pretreatment with alpha-blocker, but unaffected by parasympathetic blocker, further indicating that the depressor responses of baclofen (VMH) were not due to parasympathetic activation, but due to peripheral sympathetic depression. Muscimol (400 ng) and baclofen (800 ng) injected into VMH produced similar amplitude of sympathetic-depressant, depressor and bradycardic responses. In contrast, BP was increased by the same dose of baclofen injected into the hypothalamic depressor area (anterior hypothalamus, AH), but was unaffected by muscimol. Final experiments were performed to determine whether these sympathetic and cardiovascular effects to hypothalamic GABAB stimulations would be altered in hypertension. In spontaneously hypertensive rats (SHR), basal BP and heart rate were already higher than in normotensive controls (Wistar-Kyoto rat, WKY). Baclofen injected into VMH reduced sympathetic nerve activity, BP, and heart rate in both groups of rats, and these effects were significantly larger in SHR than in WKY. This enhanced depressor response induced by baclofen (VMH) in SHR persisted even after sinoaortic denervation, which indicates that the enhanced depressor response is not due to reduced peripheral baroreflex sensitivity in SHR. On the other hand, baclofen injected into AH increased BP and heart rate in both WKY and SHR, but the magnitude of these responses did not differ between two groups. In summary, GABA reduces sympathetic nerve activity, BP, and heart rate through both GABAA and B receptors in VMH. The GABAB system acts on the depressor area, AH, to further regulate the cardiovascular activities. In SHR, the GABAB-ergic system in VMH but not in AH is altered, and this might contribute to the development of hypertension.

[Rupture of thoracic aorta due to blunt trauma: a report of three cases]

Three cases of the thoracic aortic rupture due to blunt trauma were successfully treated. All of the cases were young male motorcyclists. The chest X-ray on admission showed either a widened mediastinum or an apical extrapleural cap sign. Ruptures were confirmed by an enhanced CT clearly showing the presence of a psuedoaneurysm and a hematoma around the isthmus of the aorta. One of them was operated upon urgently and others in whom heparin could not be used because of associated injuries were operated upon electively two and three months after the traffic accident, respectively. In two of them, aneurysms were removed and replaced with dacron grafts and in the remaining one, the aneurysm was resected and repaired directly under the femoro-femoral bypass. Post-operative courses were uneventful. They discharged and are doing well after the treatment for associated injuries. In view of the high early mortality of aortic rupture, an early diagnosis and treatment is important. But in the case who has stable hemodynamics and contraindication for heparinization, a delayed operation may be recommended.

Role of milky spots as selective implantation sites for malignant cells in peritoneal dissemination in mice

We investigated the significance of milky spots for malignant cells in peritoneal dissemination using three mouse carcinomatous peritonitis models. P388 leukemia and Colon 26 cancer cells were labeled with bromodeoxyuridine (BrdU) and mice were inoculated intraperitoneally. After 24 h the greater omentum and the mesenterium were removed and stained immunohistochemically with anti-BrdU antibody. The labeled cells were found to have preferentially infiltrated into the milky spots in these specimens. Next, using B16 PC melanoma cells, which can be easily distinguished from the other cells by the intrinsic black melanin, the distribution of the melanoma cells was observed macro- and microscopically following intraperitoneal inoculation. The melanoma cells were similarly found to have selectively infiltrated into the milky spots in the omentum and mesenterium after 1 day. Moreover, the melanoma cells were growing and forming distinct metastic lesions within the milky spots 1 week later.

Repressive regulation of the aquaporin-2 gene

Expression of aquaporin-2 (AQP2) is exclusively limited to kidney collecting duct cells, and this strictly limited expression could be mediated by transcription of the gene. We first examined AQP2 mRNA expression in many cultured epithelial cells derived from kidney. Northern blot using OK, LLC-PK1, Madin-Darby canine kidney, and outer medullary collecting duct (OMCD) cells and primary culture of inner medullary collecting duct (IMCD) cells did not reveal any significant signal. A more sensitive method, ribonuclease protection assay, could detect a faint signal in OMCD cells when they were bathed in a hypertonic medium. Reverse-transcribed polymerase chain reaction applied to primary culture of IMCD cells showed a rapid dissipation of AQP2 mRNA within 4 days after culture. A reporter gene assay performed in the 1st day of primary culture of IMCD cells showed that the 5' region up to -2.9 kb worked as a promoter. Deletion experiments showed that at least two regions, from -434 to -364 and from -153 to -84, contain negatively acting cis-elements. When connected to a heterologous promoter, these regions repressed the activity in an orientation-dependent manner. These results suggest that transcription of AQP2 gene is strictly regulated and its ability is rapidly depressed in culture condition. This cell differentiation-specific expression of the gene may be, at least in part, mediated by the repressors present in its 5'-flanking region.

IL-6 antisense-mediated growth inhibition of a choriocarcinoma cell line: an intracellular autocrine growth mechanism

The growth of tumor cells can be regulated by a variety of cytokines. To investigate the pathogenesis of choriocarcinoma and explore a new therapeutic approach for the carcinoma, we examined the role of IL-6 in the growth of a human choriocarcinoma cell line (JEG-3). IL-6 was identified in the supernatant of the cell culture medium by enzyme-linked immunosorbent assay, indicating that this cell secreted IL-6. The mRNAs of IL-6, IL-6 receptor and gP130, the IL-6 signal transducer, in this cell were shown to be present by reverse transcriptase polymerase chain reaction assay and confirmed by Southern blot hybridization and direct sequencing. The addition of hrIL-6 to the cell culture failed to stimulate cell growth. Monoclonal antibodies against IL-6, IL-6 receptor, and gP130 were also unable to inhibit the proliferation of this cell line. The antisense oligonucleotides targeting IL-6 mRNA, however, inhibited both cell growth and IL-6 production. Taken together, these findings indicate that endogenous IL-6 plays an important role in the growth of the JEG-3 cell line, and it exerts its action by an intracellular autocrine growth mechanism. The results also suggest that the therapeutic trials with monoclonal antibodies designed to neutralize IL-6 or block its receptor will likely fail, whereas the antisense oligonucleotides targeted to IL-6 mRNA may have some value for the treatment of choriocarcinoma and other cancers with intracellular autocrine growth fashion mediated by IL-6.

Stimulation of sarcoplasmic reticulum Ca(2+)-ATPase by gingerol analogues

We have reported previously that [8]-gingerol increased Ca(2+)-ATPase activity. Here we synthesized gingerol related compounds (AP-004, AP-005 and AP-015) and investigated the effects of gingerols ([6]-gingerol, [8]-gingerol and [10]-gingerol) and the synthesized compounds on the Ca(2+)-ATPase activity of sarcoplasmic reticulum (SR). The Ca(2+)-ATPase activity and the Ca(2+)-pumping activity increased by these compounds in a concentration-dependent manner. It is probable that both the o-methoxyphenol and hydrocarbon chain in the molecule of gingerol analogues are necessary for the activation of the Ca(2+)-pumping ATPase activity of SR.

Determination of absolute configuration and biological activity of new immunosuppressants, mycestericins D, E, F and G

Mycestericins D, E, F and G were isolated from the culture broth of Mycelia sterilia ATCC 20349 as potent immunosuppressants. Mycestericins F and G were identical with dihydromycestericins D and E, respectively. Their absolute configurations were determined by use of the modified MOSHER'S method and by comparison of the CD spectra of their benzoate derivatives with those of synthetic analogs. Mycestericins D, E, F and G suppressed the proliferation of lymphocytes in the mouse allogeneic mixed lymphocyte reaction.

Transforming growth factor beta is protective in host resistance against Listeria monocytogenes infection in mice

The role of transforming growth factor beta (TGF-beta) in host resistance against Listeria monocytogenes infection was studied with mice. The constitutive expression of TGF-beta 1 mRNA was observed in the spleens and livers of mice before and after infection. Injecting the mice with anti-TGF-beta 1 peptide serum resulted in diminished antilisterial resistance, whereas the administration of human platelet-derived TGF-beta 1 enhanced the resistance. Moreover, mice were protected against lethal infection when treated with TGF-beta 1. These results suggest the TGF-beta 1 might be involved in antilisterial resistance. On the other hand, injecting the mice with TGF-beta 1 resulted in a decrease in the titers of endogenous gamma interferon, tumor necrosis factor alpha, and interleukin-6, which are crucial in antilisterial resistance, in sera and in extracts of spleen and liver. Thus, a complicated mechanism might be involved in the role of TGF-beta 1 in host resistance against L. monocytogenes infection.