Calciphylaxis After Aortic Valve Replacement in a Patient with End-Stage Renal Disease

In this study, we report a case of a patient on dialysis who presented necrotic lesions on the legs and penile ulceration 7 years after a mechanical aortic valve replacement. The diagnosis of calciphylaxis was not confirmed even after skin biopsy, and multidisciplinary management was not initiated until the patient was admitted with septic shock. Cardiovascular surgeons should be aware of warfarin-induced calciphylaxis, whose pathophysiology differs from that of atherosclerosis. Considering poor long-term survival of dialysis patients, mechanical valves should be reserved only for those patients whose estimated survival is longer than the time taken for a biological valve to deteriorate.

Cellulitis Complicated with Bacteremia Due to Sphingobacterium Species: A Report of Two Cases and a Literature Review

Sphingobacterium species rarely cause human infection. We herein report two cases of cellulitis complicated with bacteremia due to this genus. The patients, both in their 70s and receiving corticosteroid therapy for their underlying diseases, had antecedent skin injuries in their affected limbs. The patients' symptoms improved promptly and completely with the administration of cefazolin, which did not inhibit the growth of isolated organisms at a concentration of 4 μg/mL.

Pyoderma gangrenosum and underlying diseases in Japanese patients: A regional long-term study

Pyoderma gangrenosum (PG) is a chronic inflammatory disease of unknown cause that presents as an inflammatory and ulcerative disorder of the skin. PG is often associated with an underlying systemic disease. However, the frequencies of the underlying diseases are unclear in Japanese patients. In this retrospective, observational study, all patients diagnosed with PG who visited dermatology departments of nine regional hospitals in and around Ibaraki Prefecture were collected from 1982 to 2011 or 2014. The diagnoses of PG were based on the characteristic clinical and histological appearances and ruling out of infection. Sixty-two PG patients, including 29 males and 33 females, were identified. The ages of onset were 16-89 years, and the mean age was 50.2 years. Fifty (80%) of the 62 patients presented with an ulcerative PG, and the lower leg was the most common site (74%). Forty-six (74%) PG patients had underlying diseases. The most frequent was ulcerative colitis (32%), followed by myelodysplastic syndrome (11%), rheumatoid arthritis (6%) and aortitis syndrome (5%). For treatment, 54 cases (87%) received systemic corticosteroids and 10 received additional treatment with cyclosporin. There was no significant correlation between underlying diseases and response to the initial treatment. Multivariate analysis revealed that the number of affected sites negatively correlated with successful initial treatment. Fifteen (24%) of the 62 cases relapsed. In conclusion, ulcerative colitis and hematological disorders were frequently associated with PG while approximately a quarter of the cases were idiopathic.

Role of vesicular nucleotide transporter VNUT (SLC17A9) in release of ATP from AR42J cells and mouse pancreatic acinar cells

ATP is released from cells in response to various stimuli. Our previous studies on pancreas indicated that pancreatic acini could be major stores of secreted ATP. In the present study, our aim was to establish the role of the vesicular nucleotide transporter (VNUT), SLC17A9, in storage and release of ATP. Freshly prepared acini from mice and AR42J rat acinar cells were used in this study. We illustrate that in AR42J cells, quinacrine (an ATP store marker) and Bodipy ATP (a fluorescent ATP analog) co-localized with VNUT-mCherry to vesicles/granules. Furthermore, in acini and AR42J cells, a marker of the zymogen granule membranes, Rab3D, and VNUT co-localized. Dexamethasone treatment of AR42J cells promoted formation of acinar structures, paralleled by increased amylase and VNUT expression, and increased ATP release in response to cholinergic stimulation. Mechanical stimulus (pressure) and cell swelling also induced ATP release, but this was not influenced by dexamethasone, most likely indicating different non-zymogen-related release mechanism. In conclusion, we propose that VNUT-dependent ATP release pathway is associated with agonist-induced secretion process and downstream purinergic signalling in pancreatic ducts.

Correlation of serum pepsinogens and gross appearances combined with histology in early gastric cancer

The correlation between serum pepsinogen (PG) levels and the gross types was investigated in 128 consecutive patients with early gastric cancer. Although there was no significant difference in age, gender, cancer location, or cancer depth among gross appearances, the distribution of histological type was significantly different between polypoid and depressed cancers: all polypoid cancers except one were intestinal type, whereas nearly a third of depressed cancers were diffuse type. All the patients in whom Helicobacter pylori status was investigated had Helicobacterpylori infection. Combination of gross appearances and histology (polypoid cancer with intestinal type, depressed cancer with intestinal type and depressed cancer with diffuse type) showed a clear difference in distribution of serum PG levels and a ratio between levels of PG I and PG II (I/II ratio). In polypoid cancer with intestinal type, a PG I level and a I/II ratio were significantly lower than those of the others. In depressed cancer with diffuse type, PG I and PG II levels were significantly higher. These findings revealed that backgrounds such as intragastric acidity and extent of gastric atrophy might differ among early gastric cancers with different morphology and histology.

[Successful surgical treatment in a nonagenarian with aortic arch aneurysm]

Surgical treatment in a nonagenarian with thoracic aortic aneurysm is challenging, and the surgical indication in such patients is controversial. A 92-year-old female patient with severe chest and back pain was transferred to our hospital because of impending rupture of an aortic arch aneurysm with normal mental activity. Physical and laboratory examinations were within normal limits. The patients underwent urgent graft replacement of the total aortic arch. Postoperative course was uneventful and the patient remains well with no disability 8 months after the operation.

Rapid, selective digestion of mitochondrial DNA in accordance with the matA hierarchy of multiallelic mating types in the mitochondrial inheritance of Physarum polycephalum

Although mitochondria are inherited uniparentally in nearly all eukaryotes, the mechanism for this is unclear. When zygotes of the isogamous protist Physarum polycephalum were stained with DAPI, the fluorescence of mtDNA in half of the mitochondria decreased simultaneously to give small spots and then disappeared completely approximately 1.5 hr after nuclear fusion, while the other mitochondrial nucleoids and all of the mitochondrial sheaths remained unchanged. PCR analysis of single zygote cells confirmed that the loss was limited to mtDNA from one parent. The vacant mitochondrial sheaths were gradually eliminated by 60 hr after mating. Using six mating types, the transmission patterns of mtDNA were examined in all possible crosses. In 39 of 60 crosses, strict uniparental inheritance was confirmed in accordance with a hierarchy of relative sexuality. In the other crosses, however, mtDNA from both parents was transmitted to plasmodia. The ratio of parental mtDNA was estimated to be from 1:1 to 1:10(-4). Nevertheless, the matA hierarchy was followed. In these crosses, the mtDNA was incompletely digested, and mtDNA replicated during subsequent plasmodial development. We conclude that the rapid, selective digestion of mtDNA promotes the uniparental inheritance of mitochondria; when this fails, biparental inheritance occurs.

High prevalence of quintuple mutant dhps/dhfr genes in Plasmodium falciparum infections seven years after introduction of sulfadoxine and pyrimethamine as first line treatment in Malawi

Malawi changed its national policy for malaria treatment in 1993, becoming the first country in Africa to replace chloroquine by sulfadoxine and pyrimethamine combination (SP) as the first-line drug for uncomplicated malaria. Seven years after this change, we investigated the prevalence of dihydropteroate synthase (dhps) and dihydrofolate reductase (dhfr) mutations, known to be associated with decreased sensitivity to SP, in 173 asymptomatic Plasmodium falciparum infections from Salima, Malawi. A high prevalence rate (78%) of parasites with triple Asn-108/Ile-51/Arg-59 dhfr and double Gly-437/Glu-540 dhps mutations was found. This 'quintuple mutant' is considered as a molecular marker for clinical failure of SP treatment of P. falciparum malaria. A total of 11 different dhfr and dhps combinations were detected, 3 of which were not previously reported. Nineteen isolates contained the single Glu-540 mutant dhps, while no isolate contained the single Gly-437 mutant dhps, an unexpected finding since Gly-437 are mostly assumed to be one of the first mutations commonly selected under sulfadoxine pressure. Two isolates contained the dhps single or double mutant coupled with dhfr wild-type. The high prevalence rates of the three dhfr mutations in our study were consistent with a previous survey in 1995 in Karonga, Malawi, whereas the prevalences of dhps mutations had increased, most probably as a result of the wide use of SP. A total of 52 P. falciparum isolates were also investigated for pyrimethamine and sulfadoxine/pyrimethamine activity against parasite growth according to WHO in vitro standard protocol. A pyrimethamine resistant profile was found. When pyrimethamine was combined with sulfadoxine, the mean EC(50) value decreased to less than one tenth of the pyrimethamine alone level. This synergistic activity may be explained by sulfadoxine inhibition of dhps despite the double mutations in the dhps genes, which would interact with pyrimethamine acting to block the remaining folate despite dhfr mutations in the low p-aminobenzoic acid and low folic acid medium mixed with blood.

The relationship of left ventricular mass to endothelium-dependent vasodilation of the brachial artery in patients with hypertension

Although echocardiographically determined left ventricular mass and geometry predict cardiovascular morbid events in patients with hypertension, the mechanisms underlying this relation are unclear. There is considerable evidence that endothelium-dependent vasodilation is impaired in patients with hypertension. Thus, endothelial dysfunction may contribute to the mechanism that causes cardiovascular morbid events. This study was designed to examine the relationship between left ventricular geometry and endothelial function in patients with hypertension. The percentage increase in brachial arterial diameter during reactive hyperemia was examined by a high-resolution ultrasound technique in 49 patients with hypertension and 64 normotensive subjects. Patients with hypertension had an impairment of the percentage increase in brachial arterial diameter during reactive hyperemia and an increase in thiobarbituric acid-reactive substances (TBARS) compared to normotensive subjects (percentage increase in diameter 5.6 +/- 3.0 vs. 8.0 +/- 2.5%, p < 0.001; TBARS levels 6.1 +/- 1.3 vs. 5.3 +/- 1.0 nmol/ml, p < 0.001). In patients with hypertension, there was a significant correlation between the left ventricular mass index and the percentage increase in brachial arterial diameter during reactive hyperemia (r = -0.583, p < 0.001), and the percentage increase in brachial arterial diameter during reactive hyperemia varied with the pattern of left ventricular geometry (normal ventricular geometry: 7.7 +/- 2.6%; concentric remodeling: 5.2 +/- 2.3%; eccentric hypertrophy: 4.2 +/- 1.8%; concentric hypertrophy: 2.9 +/- 2.6%). We conclude that (1) flow-mediated endothelium-dependent vasodilation in the brachial artery is impaired in patients with hypertension, (2) a relationship exists between the left ventricular mass index and flow-mediated endothelium-dependent vasodilation in the brachial artery in patients with hypertension and (3) increased oxidative stress may play a role in the endothelial dysfunction in patients with hypertension.

Effects of CYP2C19 genotypic differences in the metabolism of omeprazole and rabeprazole on intragastric pH

BACKGROUND

Omeprazole is mainly metabolized in the liver by CYP2C19, a genetically determined enzyme, whereas rabeprazole is mainly reduced non-enzymatically and partially metabolized by CYP2C19. The therapeutic effects of rabeprazole are therefore assumed to be less affected by an individual's CYP2C19 status.

AIM

To investigate the acid inhibitory effects and plasma levels of omeprazole and rabeprazole with reference to different CYP2C19 genotypes.

METHODS

Fifteen healthy volunteers took a daily dose of 20 mg of omeprazole or rabeprazole for 8 days. On post-dose days 1 and 8, 24-h profiles of intragastric pH were recorded and plasma concentrations of omeprazole, rabeprazole and their metabolites were determined.

RESULTS

After single and repeated doses of omeprazole, the intragastric pH values and plasma concentrations of omeprazole and its metabolites were significantly dependent on the CYP2C19 genotype. Significant differences in the same kinetic and dynamic parameters were also observed after single doses of rabeprazole. Although the plasma levels of rabeprazole differed among the different CYP2C19 genotype groups after repeated doses, no significant differences in intragastric pH values were observed.

CONCLUSIONS

The acid inhibitory effects of omeprazole and rabeprazole are significantly dependent on the CYP2C19 genotype status, as well as on their intrinsic pharmacokinetic and pharmacodynamic characteristics and dosing schemes.

Differentiation-associated Na+-dependent inorganic phosphate cotransporter (DNPI) is a vesicular glutamate transporter in endocrine glutamatergic systems

Vesicular glutamate transporter is present in neuronal synaptic vesicles and endocrine synaptic-like microvesicles and is responsible for vesicular storage of L-glutamate. A brain-specific Na(+)-dependent inorganic phosphate transporter (BNPI) functions as a vesicular glutamate transporter in synaptic vesicles, and the expression of this BNPI defines the glutamatergic phenotype in the central nervous system (Bellocchio, E. E., Reimer, R. J., Fremeau, R. T., Jr., and Edwards, R. H. (2000) Science 289, 957-960; Takamori, S., Rhee, J. S., Rosenmund, C., and Jahn, R. (2000) Nature 407, 189-194). However, since not all glutamatergic neurons contain BNPI, an additional transporter(s) responsible for vesicular glutamate uptake has been postulated. Here we report that differentiation-associated Na(+)-dependent inorganic phosphate cotransporter (DNPI), an isoform of BNPI (Aihara, Y., Mashima, H., Onda, H., Hisano, S., Kasuya, H., Hori, T., Yamada, S., Tomura, H., Yamada, Y., Inoue, I., Kojima, I., and Takeda, J. (2000) J. Neurochem. 74, 2622-2625), also transports L-glutamate at the expense of an electrochemical gradient of protons established by the vacuolar proton pump when expressed in COS7 cells. Molecular, biological, and immunohistochemical studies have indicated that besides its presence in neuronal cells DNPI is preferentially expressed in mammalian pinealocytes, alphaTC6 cells, clonal pancreatic alpha cells, and alpha cells of Langerhans islets, these cells being proven to secrete L-glutamate through Ca(2+)-dependent regulated exocytosis followed by its vesicular storage. Pancreatic polypeptide-secreting F cells of Langerhans islets also expressed DNPI. These results constitute evidence that DNPI functions as another vesicular transporter in glutamatergic endocrine cells as well as in neurons.

Application of combined reagent solution to the oxidative refolding of recombinant human interleukin 6

Human interleukin 6 (hIL-6), which is a cytokine involved in diverse biological activities, consists of a four-helix bundle with two disulfide bonds. For the clinical use of hIL-6 in cancer therapy, designing of commercial-scale production systems of recombinant hIL-6 (rhIL-6) expressed by E. coli has been attempted. Since rhIL-6 has been produced as inclusion bodies in the expression systems reported to date, establishment of a strategy to achieve a high yield of refolding of this recombinant protein is quite desirable. It has been reported that oxidation of rhIL-6 under a completely denaturing condition suppresses aggregation during the refolding process [Ejima et al., Biotechnol. Bioeng., 62, 301-310 (1999)]. In this protocol, however, small but significant amounts of unidentified by-products unavoidably arose, which might be problematic in the therapeutic use of rhIL-6. In the present study, detailed characterization of the individual by-products has been performed on inspection of peptide maps, and the by-products found to originate from improperly formed disulfide bonds, most of which are disulfide-linked dimers. In order to minimize these by-products, combined solutions of urea and LiCl were used for oxidative refolding of rhIL-6. It was demonstrated that combined use of 1-2 M urea and 1-3 M LiCl effectively suppresses the formation of the by-products as well as aggregates. We propose that the use of the combined reagents can be an alternative method for refolding of rhIL-6 for clinical purposes.

Effect of a neutrophil elastase inhibitor (ONO-5046 Na) on ischemia/reperfusion injury using the left-sided heterotopic canine heart transplantation model

BACKGROUND

Ischemia/reperfusion injury is a major cause of transplanted heart dysfunction. Several reports have demonstrated that polymorphonuclear neutrophil (PMN) elastase derived from the activated neutrophils might play an important role in this injury. Herein, we investigated the protective effects of PMN elastase inhibitor (ONO-5046 Na) on ischemia/reperfusion injury using a left-sided canine heterotopic heart transplantation model.

METHODS

We used 10 pairs of adult beagle dogs. The donor heart was transplanted heterotopically into the left thoracic cavity of the recipient without cardiopulmonary bypass. A bolus of ONO-5046 Na (10 mg/kg) was introduced intravenously to 5 recipients (group II) at 15 minutes before reperfusion and was followed by continuous infusion (10 mg/kg per hour) for 180 minutes. Five dogs (group I) did not receive ONO-5046 Na and thus served as a control. After reperfusion, we evaluated transplanted heart function and obtained blood samples from the coronary sinus over a 360-minute period.

RESULTS

E(max) and pre-load recruitable stroke work in group II showed significantly better recovery than group I. Blood levels of PMN elastase, creatine kinase MB, lactate and inflammatory cytokines (tumor necrosis factor-alpha, interleukin-6, interleukin-8) were significantly lower in group II. Depletion of myocardial concentration of adenosine triphosphate at 120 minutes after reperfusion and myocardial water content was significantly lower in group II.

CONCLUSIONS

ONO-5046 Na, which inhibits PMN elastase, could reduce ischemia/reperfusion injury in heart transplantation. These results indicate that clinical application of ONO-5046 Na should be considered.

Possible remediation of dioxin-polluted soil by steam distillation

2,7-Dichlorodibenzo-p-dioxin (DCDD) was found to evaporate easily with water vapor from a heated solution. Steam distillation was also effective for the removal of DCDD from DCDD-applied soil; its concentration (250 microg/50g soil) in the original soil decreased to less than 5% after steam distillation for only 20 min. Actual dioxin-polluted soil in Tokorozawa City was partially decontaminated using the same method. These results suggest that steam distillation could be a new remedial method for soils contaminated with persistent environmental pollutants, such as dioxins and polychlorinated biphenyls.

D-Aspartate is stored in secretory granules and released through a Ca(2+)-dependent pathway in a subset of rat pheochromocytoma PC12 cells

D-Aspartate in mammalian neuronal and neuroendocrine cells is suggested to play a regulatory role(s) in the neuroendocrine function. Although D-aspartate is known to be released from neuroendocrine cells, the mechanism underlying the release is less understood. Rat pheochromocytoma PC12 cells contain an appreciable amount of D-aspartate (257 +/- 31 pmol/10(7) cells). Indirect immunofluorescence microscopy with specific antibodies against d-aspartate indicated that the amino acid is present within a particulate structure, which is co-localized with dopamine and chromogranin A, markers for secretory granules, but not with synaptophysin, a marker for synaptic-like microvesicles. After sucrose density gradient centrifugation of the postnuclear particulate fraction, about 80% of the d-aspartate was recovered in the secretory granule fraction. Upon the addition of KCl, an appreciable amount of D-aspartate (about 40 pmol/10(7) cells at 10 min) was released from cultured cells on incubation in the presence of Ca(2+) in the medium. The addition of also triggered d-aspartate release. Botulinum neurotoxin type E inhibited about 40% of KCl- and Ca(2+)-dependent d-aspartate release followed by specific cleavage of 25-kDa synaptosomal-associated protein. alpha-Latrotoxin increased the intracellular [Ca(2+)] and caused the Ca(2+)-dependent d-aspartate release. Bafilomycin A1 dissipated the intracellular acidic regions and inhibited 40% of the Ca(2+)-dependent D-aspartate release. These properties are similar to those of the exocytosis of dopamine. Furthermore, digitonin-permeabilized cells took up radiolabeled d-aspartate depending on MgATP, which is sensitive to bafilomycin A1 or 3,5-di-tert-butyl-4-hydroxybenzylidene-malononitrile. Taken together, these results strongly suggest that d-aspartate is stored in secretory granules and then secreted through a Ca(2+)-dependent exocytotic mechanism. Exocytosis of D-aspartate further supports the role(s) of D-aspartate as a chemical transmitter in neuroendocrine cells.

Clinical experience with temporary vena cava filters

An experience with temporary filter placement, which seems to be safe and effective for temporarily preventing pulmonary embolism, is reported. Since October 1997, six patients had temporary filters. There were two men and four women, with a mean age of 37 years. Three filters were placed at the infrarenal inferior vena cava, two at the suprarenal inferior vena cava, and one at the superior vena cava. All filters were placed before various surgical interventions. During filter placement, anticoagulation therapy was routinely performed. There were no complications at and during filter placement. No pulmonary emboli occurred during surgical intervention. All filters were successfully removed, two of which were exchanged for permanent filters. All patients are alive and well without recurrent deep vein thrombosis and/or pulmonary emboli during a follow-up period of 11 to 25 months. Although this experience is small, temporary filter placement is safe and effective for short-term prevention of pulmonary emboli even in older patients or those with malignant disease. Veins of the upper part of the body may be more favorable than the femoral vein for insertion of a temporary filter. Temporary filters can be safely placed not only at the infrarenal inferior vena cava, but also at the suprarenal inferior vena cava or superior vena cava.

Phase III study comparing tacrolimus (FK506) with cyclosporine for graft-versus-host disease prophylaxis after allogeneic bone marrow transplantation

We report the results of a phase III trial comparing tacrolimus (FK506) with cyclosporine for GVHD prophylaxis after allogeneic BMT. From February 1995 to July 1996, 136 patients were enrolled and followed up to September 1997. During the first 100 days post-transplant the incidence of grade II-IV acute GVHD (the primary end-point) was lower in the tacrolimus group (17.5%) compared with the cyclosporine group (48.0%, P < 0.0001). A significant difference was observed between the tacrolimus and cyclosporine groups when subset analyses were performed based on recipients from HLA-matched siblings (13.3% vs 41.3%, P = 0.015) or donors other than HLA-matched siblings (21.4% vs 53.8%, P= 0.0029). The incidence of chronic GVHD (47.3% and 47.8%) and Kaplan-Meier estimate of overall survival (62.9% and 65.2%) were similar between the tacrolimus and cyclosporine groups, respectively. The overall leukemia relapse rate was not significantly different between the tacrolimus and cyclosporine groups (19.6% and 11.4%, respectively). However, the relapse rate among recipients from HLA-matched siblings was significantly higher in the tacrolimus group (30.9%) compared with the cyclosporine group (3.6%, P = 0.013). These results suggest the merit of tacrolimus for the prophylaxis of acute GVHD, but a lack of merit for a graft-versus-leukemia effect among recipients from HLA-matched sibling donors.

A leukocyte depleting filter reduces endothelial cell dysfunction and improves transplanted canine heart function

BACKGROUND

To date leukocytes have been known to play a major role in reperfusion injury and have directed attention to leukocyte-endothelium interaction. This study was designed to investigate how much graft viability and the coronary microcirculatory function could be preserved by leukocyte depletion (LD) in a model of orthotopic cardiac transplantation.

METHODS

The heart in 10 beagle dogs was arrested by introducing a 4 degrees C St. Thomas' cardioplegic solution. They were harvested, immersed in the cold saline for 3 hours, and then orthotopically transplanted. Five recipients underwent LD (LD group) at reperfusion with the use of a Pall BC1B leukocyte depleting filter inserted into the cardiopulmonary bypass (CPB) circuit. The other 5 dogs without filtration served as a control group.

RESULTS

Leukocytes were about 80% filtrated and neutrophils were also 85% filtrated during the first 30 minutes of reperfusion in the LD group. A high level of adenosine triphosphate was maintained after transplantation in the LD group. The polymorphonuclear elastase level was significantly lower in the LD group. The cardiac function assessed by the slopes of the end-systolic pressure volume relation after transplantation was significantly higher in the LD group than in the control group (p < 0.05). The coronary vascular resistance responses to acetylcholine and nitroglycerin after transplantation were preserved significantly better in the LD group than in the control group (p < 0.05).

CONCLUSIONS

These results suggest that a leukocyte depleting filter placed in the CPB circuit would prevent leukocyte-mediated endothelial cell injury, improve microcirculation of the myocardium, and lead to excellent graft function.

[Pharmacological and therapeutic properties of lafutidine (stogar and protecadin), a novel histamine H2 receptor antagonist with gastroprotective activity]

Potent antisecretory agents, such as histamine H2-receptor antagonists and proton pump inhibitors, have achieved great improvement in peptic ulcer therapy. It has, however, been reported that incidence of ulcer relapse is high after discontinuation of these drugs. Insufficient efficacy against NSAID-induced ulcers is also critical. Lafutidine is a novel histamine H2 antagonist with gastroprotective activity. Lafutidine exhibited potent and long-lasting H2 antagonism and prolonged antisecretion. In addition, lafutidine showed a gastroprotective effect against noxious agents-induced gastric mucosal damage through capsaicin-sensitive afferent nerves. Lafutidine showed antiulcer activities against acute ulcer models, prevented gastric ulcer relapse of acetic ulcer, and accelerated the healing of indomethacin-induced antral ulcers in rats. These results suggest the advantage of the combined antisecretory and gastroprotective activities. In clinical studies, lafutidine showed prolonged antisecretion, healing effect against gastric and duodenal ulcers and gastritis, and its potency was equal or superior to that of conventional H2 antagonists. Additionally, lafutidine induced a high transition rate to the E0 stage determined by endoscopical ultrasonography, suggesting the high quality of ulcer healing. Furthermore, effectiveness of lafutidine against NSAIDs-induced ulcer was high. From these results, lafutidine is equal or superior to conventional H2 antagonists in antiulcer potency, and it may be useful for the prevention of ulcer relapse and or treatment of NSAIDs-induced gastroduodenal damage.

Cloning of a lymphatic peptide/histidine transporter

Although peptide transport across the plasma membrane has been characterized well in the kidney and the intestine, the functional relevance of this transport in other organs has not been addressed. Here we report the cloning of a cDNA for a novel peptide/histidine transporter found in the rat (rPHT2), whose mRNA is expressed mainly in the lymphatic system. rPHT2 encodes a protein of 582 amino acids and showed 49% identity with the brain PHT (PHT1) [Yamashita, Shimada, Guo, Sato, Kohmura, Hayakawa, Takagi and Tohyama (1997) J. Biol. Chem. 272, 10205-10211]. rPHT2 mRNA was abundant in lung, spleen and thymus, and detected faintly in brain, liver, adrenal gland and heart by Northern-blot analysis and reverse transcriptase PCR (RT-PCR). Intense signals for the gene were found in immunocytes using in situ hybridization. Ectopic expression of rPHT2 protein in HEK-293T cells and BHK cells was not found on the cell surface, but was found on the lysosomal membrane using light- and electron-microscopic analysis. Recombinant rPHT2 protein reconstituted into liposomes showed proton-dependent transport activity with histidine and histidyl-leucine. These findings suggest that rPHT2 is involved in the protein catabolic pathway in the lymphatic system.

A homologue of N-ethylmaleimide-sensitive factor in the malaria parasite Plasmodium falciparum is exported and localized in vesicular structures in the cytoplasm of infected erythrocytes in the brefeldin A-sensitive pathway

N-Ethylmaleimide-sensitive factor (NSF) and its homologues play a central role in vesicular trafficking in eukaryotic cells. We have identified a NSF homologue in Plasmodium falciparum (PfNSF). The reported PfNSF gene sequence (GenBank accession number CAB10575) indicated that PfNSF comprises 783 amino acids with a calculated molecular weight of 89,133. The overall identities of its gene and amino acid sequences with those of rat NSF are 50.9 and 48.8%, respectively. Reverse transcription-polymerase chain reaction analysis and Northern blotting with total P. falciparum RNA indicated expression of the PfNSF gene. Polyclonal antibodies against a conserved region of NSF specifically recognized an 89-kDa polypeptide in the parasite cells. After homogenization of the parasite cells, approximately 90% of an 89-kDa polypeptide is associated with particulate fraction, suggesting membrane-bound nature of PfNSF. PfNSF was present within both the parasite cells and the vesicular structure outside of the parasite cells. The export of PfNSF outside of the parasite cells appears to occur at the early trophozoite stage and to terminate at the merozoite stage. The export of PfNSF is inhibited by brefeldin A, with 9 microM causing 50% inhibition. Immunoelectromicroscopy indicated that intracellular PfNSF was associated with organelles such as food vacuoles and that extracellular PfNSF was associated with vesicular structures in the erythrocyte cytoplasm. These results indicate that PfNSF expressed in the malaria parasite is exported to the extracellular space and then localized in intraerythrocytic vesicles in a brefeldin A-sensitive manner. It is suggested that a vesicular transport mechanism is involved in protein export targeted to erythrocyte membranes during intraerythrocytic development of the malaria parasite.

Acute effects of melatonin administration on cardiovascular autonomic regulation in healthy men

BACKGROUND

Previous studies have suggested that melatonin, a major pineal hormone, possibly modulates the autonomic nervous system in animals. The aim of this study was to examine the effects of melatonin administration on heart rate variability (HRV) in human beings.

METHODS

In 26 healthy men, melatonin (2 mg) or placebo was randomly administered. Power spectral analysis of HRV and blood pressure monitoring were performed in the supine position before and 60 minutes after administration and in the standing position 60 minutes after administration. Plasma catecholamine levels were also assessed.

RESULTS

No differences in any baseline parameters were found between the two groups. Compared with placebo, melatonin administration within 60 minutes increased R-R interval, the square root of the mean of the squared differences between adjacent normal R-R intervals, high-frequency power, and low-frequency power of HRV and decreased the low-frequency to high-frequency ratio and blood pressure in the supine position (all P <.01). Plasma norepinephrine and dopamine levels in the supine position 60 minutes after melatonin administration were lower compared with placebo (P <.05 and P <.01, respectively). Standing up resulted in the decrease of HRV and the increase of blood pressure and plasma catecholamine levels in both administration groups, and the differences between the groups found in the supine position disappeared.

CONCLUSIONS

These findings indicate that melatonin administration increased cardiac vagal tone in the supine position in awake men. Melatonin administration also may exert suppressive effects on sympathetic tone.

Ca2+-dependent exocytosis of L-glutamate by alphaTC6, clonal mouse pancreatic alpha-cells

Pancreatic islet cells express receptors and transporters for L-glutamate and are thus believed to use L-glutamate as an intercellular signaling molecule. However, the mechanism by which L-glutamate appears in the islets is unknown. In the present study, we investigated whether L-glutamate is secreted through exocytosis by alphaTC6 cells (clonal mouse pancreatic alpha-cells). An appreciable amount of L-glutamate was released from cultured cells after the addition of KCl or A23187 in the presence of Ca2+ and 10 mmol/l glucose in the medium. The KCl-induced glutamate release was significantly reduced when assayed in the absence of Ca2+ or when the cells were pretreated with EGTA-AM. The KCl-induced Ca2+-dependent glutamate release was inhibited approximately 40% by voltage-gated Ca2+ channel blockers, such as nifedipine at 20 micromol/l. The degree of KCl-induced Ca2+-dependent glutamate release was correlated with an increase in intracellular [Ca2+], as monitored by fura-2 fluorescence. Botulinum neurotoxin type E inhibited 55% of the KCl-induced Ca2+-dependent glutamate release, followed by specific cleavage of 25 kDa synaptosomal-associated protein. Furthermore, bafilomycin A1, a specific inhibitor of vacuolar H+-ATPase, inhibited 40% of the KCl-induced Ca2+-dependent glutamate release. Immunoelectronmicroscopy with antibodies against synaptophysin, a marker for neuronal synaptic vesicles and endocrine synaptic-like microvesicles, revealed a large number of synaptophysin-positive clear vesicles in cells. Digitonin-permeabilized cells took up L-glutamate only in the presence of MgATP, which is sensitive to bafilomycin A1 or 3,5-di-tert-butyl-4-hydroxybenzylidene-malononitrile (a proton conductor) but insensitive to either oligomycin or vanadate. From these results, it was concluded that alphaTC6 cells accumulate L-glutamate in the synaptophysin-containing vesicles in an ATP-dependent manner and secrete it through a Ca2+-dependent exocytic mechanism. The Ca2+-dependent glutamate release was also triggered when cells were transferred in the medium containing 1 mmol/l glucose, suggesting that low glucose treatment stimulates the release of glutamate. Our results are consistent with the idea that L-glutamate is secreted by alpha-cells through Ca2+-dependent regulated exocytosis.

Tumor-suppressor effect of interferon regulatory factor-1 in human hepatocellular carcinoma

IFN regulatory factor-1 (IRF-1) regulates the IFN system, inhibits cell growth, and has tumor-suppressor activities. p21 is a universal cyclin-dependent kinase inhibitor, the induction of which depends on both p53 and IRF-1 in mouse embryonic fibroblasts. The expression of p21 in hepatocellular carcinomas (HCCs) is regulated by wild-type p53. We examined the expressions of IRF-1 and p21 in 32 HCCs by quantitative reverse transcription-PCR and the mutation p53 gene in 32 HCCs by single-strand conformation polymorphism and direct sequencing. The expression of IRF-1 mRNA in 15 of 32 HCCs was lower than that in adjacent noncancerous tissue. IRF-1 mRNA expression was reduced in 0 of 3 specimens of well-differentiated HCC, 9 of 21 (42%) specimens of moderately differentiated HCC, and 6 of 8 (75%) specimens of poorly differentiated HCC. IRF-1 mRNA expression was significantly lower in tumors with portal thrombus than in those without portal thrombus (P = 0.003). p53 mutations were detected in 7 of 32 HCCS: p21 expression was reduced in 6 of the 7 (86%) HCCs with p53 mutations. In contrast, p21 expression was reduced in 13 of 25 (52%) HCCs with wild-type p53. IRF-1 expression was reduced in 7 of 13 (53%) HCCs with both wild-type p53 and reduced expression of p21. These results suggest that IRF-1 may be a tumor-suppressor gene for HCC and that IRF-1 is related to p21 expression in HCC with wild-type p53.

Thoracoabdominal aortic aneurysms repair under abdominal cavity cooling with visceral shunting technique--a case report

Mild hypothermia induced by abdominal cavity cooling together with a selective visceral shunting technique can be a useful adjunct for thoracoabdominal aortic aneurysm repair. The authors adopted this combined technique for repair of selected Crawford type III and type IV aneurysms to reduce visceral ischemic damage and minimize the incidence of postoperative complications.

Penetrating atherosclerotic ulcer

The pathogenesis of penetrating atherosclerotic ulcer (PAU) in aortic disease remains controversial. Between January 1995 and April 1999, five patients underwent treatment for a PAU in our hospital. All were men, ranging in age from 46 to 74 years, with a mean age of 66.2 years. The PAU was located on the thoracic descending aorta in three patients and on the abdominal aorta in two. Preoperative diagnosis was established by contrast-enhanced computed tomographic scan and aortogram. Surgery was performed in four patients, as graft replacement in three, and patch plasty in one. The remaining patient is being carefully observed on antihypertensive therapy. No connective tissue disorder, trauma, dissection, or infection was seen in any of the patients who underwent surgery, all of whom had uneventful postoperative courses with no perioperative complications or enlargement of the aorta. We conclude that surgical treatment should be performed for patients with PAU to prevent an aortic catastrophe caused by rapid development of the lesion. This report might provide further evidence of the importance of PAU.

Increased plasminogen activator inhibitor activity and diabetes predict subsequent coronary events in patients with angina pectoris

BACKGROUND

Plasminogen activator inhibitor (PAI) is a marker of recurrence of myocardial infarction. Diabetes mellitus is also an important risk factor of coronary artery disease, including myocardial infarction and angina pectoris.

AIM

We examined baseline plasma PAI activity levels, clinical variables, and angiographic findings and assessed them as prospective values for subsequent coronary events, such as sudden death, nonfatal myocardial infarction and coronary revascularization by percutaneous transluminal coronary angioplasty or coronary artery bypass surgery during the follow-up period.

METHODS

We conducted a prospective study for 4 years of 249 consecutive patients admitted with angina pectoris. Blood samples for PAI were drawn at discharge.

RESULTS

In the multivariate Cox proportional hazard model, PAI activity and diabetes mellitus were significant and independent risk factors (the risk increased by 10% in those with a higher PAI concentration and by 70% in diabetic patients). Event-free survival was reduced by higher PAI activity (> or = 8.4 IU/mL) and the presence of diabetes. The patients with higher PAI activity and diabetes had a 4.2-fold risk in comparison with the patients with lower PAI activity and no diabetes. However, patients with lower PAI activity were less likely to have coronary events even when they had diabetes.

CONCLUSIONS

Higher PAI activity and diabetes predict subsequent coronary events in patients with angina pectoris. Diabetes has less prognostic value for subsequent coronary events in patients with lower PAI activity.

Combined revascularization strategy for acute myocardial infarction in patients with intracoronary thrombus: preceding intracoronary thrombolysis and subsequent mechanical angioplasty

Thrombus in the infarct-related artery is one of the limitations for flow restoration in primary percutaneous transluminal coronary angioplasty (PTCA) treatment for acute myocardial infarction (AMI). The present study investigated the benefit of preceding intracoronary thrombolysis (ICT) by retrospectively analyzing acute phase flow restoration in 80 AMI patients with intracoronary thrombus: 40 undergoing primary PTCA alone (primary PTCA group) and 40 treated with preceding ICT plus PTCA (combined group). Acute phase Thrombolysis in Myocardial Infarction (TIMI) grade flow was as follows: TIMI 0/1: 35.0% vs 12.5% for the primary PTCA group and the combined group, p=0.06; TIMI 2: 7.5% vs 15.0%, p=NS; TIMI 3: 57.5% vs 72.5%, p=NS). In the subgroup analysis, it was also less in the combined group among 33 patients with a left anterior descending coronary artery (LAD) lesion (42.1 % vs 7.1%, p=0.08), but not among the remaining 47 with either a right coronary artery or left circumflex artery lesion. The combined therapy may potentially provide better acute phase flow restoration in AMI patients with an intracoronary thrombus in a LAD lesion.

Double left renal vein associated with abdominal aortic aneurysm

Double left renal vein is a rare venous anomaly. We operated on 72-year-old man of abdominal aortic aneurysm (AAA) with double left renal vein. Massive hemorrhage was encountered during encircling the tape around the abdominal aorta. One vein passing posterior to the aorta was injured. Further dissection revealed the presence of double left renal vein forming a ring around the aorta. The patient underwent an abdominal aortic replacement following prompt repair of the injured vein. He had an uneventful postoperative course without renal complication. We missed that preoperative computed tomographic (CT) scan had demonstrated double left renal vein. Preoperative contrast-enhanced CT scan is useful and essential not only for evaluation of AAA, but also for establishing the presence of venous anomalies. Venous anomalies should be taken into consideration on the AAA operation.

[Experience of four cases of postoperative pulmonary embolism requiring surgical treatment]

Four patients underwent a pulmonary embolectomy using cardiopulmonary bypass for acute pulmonary embolism which had occurred after various operations. In two cases, dehydration due to either diabetes insipidus or ileus had existed. In two cases, pulmonary embolism suddenly occurred in our hospital. In the remainder, the disease occurred in the previous hospitals and its diagnosis was established on the 6th and 7th postoperative days, respectively. In massive pulmonary embolism, echocardiography and/or enhanced chest CT are useful for prompt and noninvasive diagnosis. Thrombolytic therapy was performed in only one case before surgical embolectomy, which was not effective. Three patients were discharged without any postoperative complications, but one requiring preoperative external cardiac massage died of multiple organ failure 9 days after operation. Acute pulmonary embolism is one of the fatal postoperative complications. Recognition of this entity, and prompt diagnosis and treatment are essential for managing the fatal disease. Even in the early postoperative period, embolectomy using cardiopulmonary bypass is a safe and effective treatment.

Nitric oxide-mediated vasodilatation is decreased in forearm resistance vessels in patients with coronary spastic angina

It has been reported that coronary endothelial dysfunction is associated with the pathogenesis of coronary spasm, and that endothelial nitric oxide (NO) mediated vasodilatation was decreased in coronary epicardial arteries in patients with coronary spastic angina (CSA). However, there are few reports about the endothelial function in peripheral resistance vessels of patients with CSA, so the present study investigated the role of NO in forearm resistance vessels in such patients. The responses of forearm blood flow to acetylcholine (ACh; 8-24 microg/min) and sodium nitroprusside (SNP; 0.4-1.2 microg/ml) infusions was examined using plethysmography, and subsequently the responses to ACh after an infusion of N(G)-monomethyl-L-arginine (L-NMMA; 4 micromol/min, for 5 min) in 17 patients with CSA and 17 age- and sex- matched controls. The vasodilator responses to ACh and SNP were comparable between the 2 groups (p=NS). L-NMMA significantly suppressed the vasodilator responses to ACh in controls (p<0.05), but there was no significant difference in the responses to ACh before and after infusion of L-NMMA in patients with CSA (p=NS). These results indicate that endothelial NO-mediated vasodilatation is decreased in the forearm resistance vessels of patients with CSA.

The complete DNA sequence of the mitochondrial genome of Physarum polycephalum

The complete sequence of the mitochondrial DNA (mtDNA) of the true slime mold Physarun polycephalum has been determined. The mtDNA is a circular 62,862-bp molecule with an A+T content of 74.1%. A search with the program BLAST X identified the protein-coding regions. The mitochondrial genome of P. polycephalum was predicted to contain genes coding for 12 known proteins [for three cytochrome c oxidase subunits, apocytochrome b, two F1Fo-ATPase subunits, five NADH dehydrogenase (nad) subunits, and one ribosomal protein], two rRNA genes, and five tRNA genes. However, the predicted ORFs are not all in the same frame, because mitochondrial RNA in P. polycephalum undergoes RNA editing to produce functional RNAs. The nucleotide sequence of an nad7 cDNA showed that 51 nucleotides were inserted at 46 sites in the mRNA. No guide RNA-like sequences were observed in the mtDNA of P. polycephalum. Comparison with reported Physarum mtDNA sequences suggested that sites of RNA editing vary among strains. In the Physarum mtDNA, 20 ORFs of over 300 nucleotides were found and ORFs 14 19 are transcribed.

Superior vena caval placement of a temporary filter: a case report

Placement of permanent filters in the superior vena cava (SVC) for preventing pulmonary embolism (PE) arising from thrombi superior to the right atrium has rarely been performed. The authors report the first case of temporary filter insertion in the SVC because of upper extremity thrombosis accompanied with PE. After thrombectomy, the temporary filter was successfully removed. It is recommended to use a temporary filter, especially in young patients with upper extremity thrombosis requiring temporary prophylaxis against PE.

Thoracic and thoracoabdominal aneurysm repair under deep hypothermia using subclavian arterial perfusion

BACKGROUND

Hypothermic circulatory arrest is a valuable adjunct for thoracic and thoracoabdominal aortic aneurysm repair. Retrograde aortic perfusion through the femoral artery, however, carries a risk of cerebral embolism or malperfusion. To avoid these complications we adopted antegrade aortic perfusion through a prosthetic graft attached to the left subclavian artery through a left thoracotomy.

METHODS

Ten patients had repair of descending thoracic and thoracoabdominal aortic aneurysm under deep hypothermia with antegrade aortic perfusion through the left subclavian artery. Hypothermic circulatory arrest was used because proximal aortic control was hazardous due to rupture or intraluminal disease, or for spinal cord protection.

RESULTS

There was no brain injury and one hospital death. The cause of death was massive bleeding from the gastrointestinal tract not related to deep hypothermia or the perfusion method. All 9 survivors were alive and well after a mean follow-up period of 9 months.

CONCLUSIONS

Using the left subclavian artery as a site of aortic perfusion can avoid retrograde aortic perfusion, hence reducing the potential for brain injury due to embolic stroke or malperfusion through a dissected thoracoabdominal aorta.

Distal arch aneurysm repair using stent-grafting and ascending aorto-left axillary bypass

BACKGROUND

Transcatheter application of a stent-graft to the angulated aortic segments with critical side branches poses some problems. We report our technique of distal arch aneurysm repairs using stent-grafts inserted through the aortic arch and ascending aortoaxillary bypass.

PATIENTS AND RESULTS

Three patients underwent successful distal arch aneurysm repair using a homemade semiflexible stent-graft placed under hypothermic circulatory arrest. The left subclavian artery was reconstructed by an extraanatomic bypass grafting between the ascending aorta and left axillary artery. Postoperative imaging demonstrated reduction of aneurysm size and no endoleaks from an intercostal artery.

CONCLUSIONS

Our technique seems to be useful for repair of distal arch aneurysms and is a less invasive procedure.

Operation for adult patent ductus arteriosus using cardiopulmonary bypass

BACKGROUND

Surgical repair of adult patent ductus arteriosus is more hazardous than when performed on young patients.

METHODS

Nine adult patent ductus arteriosus patients underwent surgical repair between January 1986 and December 1998. There were 3 male and 6 female patients (mean age 55.0 years). The ratio of pulmonary blood flow to systemic flow was 2.40 +/- 0.95, and pulmonary arterial pressure was 56.0 +/- 26.4 mm Hg. The operation was performed using transpulmonary approach under total cardiopulmonary bypass. Balloon occlusion method was also utilized.

RESULTS

Direct closure was made in 5 and patch closure in 4 patients. Cardiopulmonary bypass and balloon occlusion were safely established. Cardioplegic arrest was not required in the 2 most recent patients. No operative death has occurred. Pulmonary arterial systolic pressure decreased to 35.3 +/- 6.6 mm Hg at 6 months after operation. The mean follow-up period for all patients is 55 months. To date, neither recannalization of the ductus nor pseudoaneurysm has been recognized.

CONCLUSIONS

Cardiopulmonary bypass with balloon occlusion provides a safe operation for adult patients with complicated patent ductus arteriosus.

Ionotropic glutamate receptors expressed in human retinoblastoma Y79 cells

Mammalian retinal photoreceptors and pinealocytes have common characteristic that they secrete melatonin and L-glutamate as chemical transmitters. Although pinealocytes express glutamate receptors and receive glutamate signals, whether or not photoreceptors express glutamate receptors is unknown. Here, we investigated the expression of the glutamate receptors in cultured Y79 clonal human retinoblastoma cells, as model systems of photoreceptors. Reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that GluR1, GluR5, GluR7, EAA2, NR1, NR2A and NR2D mRNAs were present in the cultured cells. Northern analysis confirmed the presence of GluR7, EAA2, NR1, NR2A and NR2D mRNAs, while other mRNAs were under the detection limit. Addition of (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid or kainate increases intracellular (Ca(2+)) in Fura-2 loaded cells, which is blocked by 6-cyano-7-nitroquinoxaline-2,3-dione. N-methyl-D-aspartate also increases intracellular (Ca(2+)). These results demonstrated the presence of functional ionotropic receptors in Y79 cells.