Influence of aerobic exercise training on brain natriuretic peptide secretion in patients in the chronic phase of myocardial infarction

Brain natriuretic peptide (BNP) secretion increases after myocardial infarction (MI); its plasma level may reflect the degree of left ventricular dysfunction. This study examines how aerobic exercise therapy for MI influences BNP secretion. Subjects included 70 patients (mean age, 62.0+/-11.3 years) who were divided into four groups: (1) 20 patients with an anterior MI and exercise training; (2) 20 patients with an anterior MI and no exercise training; (3) 15 patients with an inferior MI and exercise training; and (4) 15 patients with an inferior MI and no exercise training. The training groups performed aerobic exercise 3 times a week for 2 months. Exercise intensity was defined as a heart rate of anaerobic threshold (AT), derived from the treadmill cardiopulmonary exercise testing at 1 month after the onset of MI. The subjects underwent cardiopulmonary exercise testing again at 3 months after the onset of MI. To measure BNP, blood samples were obtained in the resting state and immediately after the peak exercise. AT and peak oxygen uptake increased in the training group with anterior MI and in both the training and nontraining groups with inferior MI. Significant serial change in plasma BNP level was not observed in the inferior MI groups. Plasma BNP level decreased longitudinally only in the nontraining anterior MI group. It was concluded that exercise training in patients with an anterior MI could delay the recovery of left ventricular function, but will increase exercise tolerance.

Genotoxic activity of chlorinated butenoic acids in Salmonella typhimurium strains TA98, TA100 and TA104

The mutagenic activities of several chlorinated butenoic acids, recently identified in chlorinated drinking waters, were determined by the Salmonella microsome assay. The Salmonella typhimurium tester strains TA98, TA100, and TA104 were used without S9 mix. The results from the investigation showed that (Z)-2-chloro-3-(dichloromethyl)-4-oxobutenoic acid (MX, in the open form) was the most potent mutagen of the compounds tested. However, a significant number of mutations was also induced by compounds with structural similarities to MX. In general, all the compounds, except the butenedioic acids, were mutagenic in the assays for both base-pair substitution strains (TA100, TA104) and for the frameshift strain TA98, with the highest mutagenic response observed in strain TA100. When the aldehyde group of MX and of 2-chloro-3-(chloromethyl)-4-oxobutenoic acid (CMCF, in the open form) was replaced by a dichloromethyl group, the mutagenic response in strains TA98 and TA104 changed. We concluded that a frame-shift mutation occurred because of the replacement. The increase of the TA104 mutagenicity suggested that adenosine could be the target for these types of compounds. Further evidence for such possibility were the modified adenosine adducts we could identify for some chlorinated butenoic acids.

[Allergic bronchopulmonary aspergillosis effectively treated with itraconazole]

A 23-year-old man with bronchial asthma presented with fever, cough, and sputum. A chest X-ray examination showed pulmonary infiltrations in the left upper and lower lung fields with central bronchiectasis. Although his temperature came down with antibiotics, pulmonary infiltrations persisted with cough and sputum. Following bronchoscopy and an allergological examination, the patient was given a diagnosis of allergic bronchopulmonary aspergillosis (ABPA) based on Rosenberg's criteria, including peripheral blood eosinophilia, a high serum IgE level, immediate skin reaction to Aspergillus antigen, positive precipitating antibodies, and Aspergillus fumigatus in sputum. The patient was treated with itraconazole instead of corticosteroids. His respiratory symptoms, eosinophilia, and pulmonary infiltration then disappeared, and his IgE serum level gradually decreased. An antifungal agent alone was effective in treating this ABPA patient.

Surgical complications of pediatric kidney transplantation: a single center experience with the extraperitoneal technique

PURPOSE

The complex nature of pediatric renal transplantation and the often fragile condition of children with end stage renal disease create the potential for a number of complications. To decrease surgical complications we have performed renal transplantation via the extraperitoneal approach at our institution even in children who weigh less than 20 kg. We retrospectively evaluated whether renal transplantation via the extraperitoneal approach decreases surgical complications in pediatric kidney transplant recipients.

MATERIALS AND METHODS

From February 1983 to December 1996, 1,115 patients underwent renal transplantation at our institution, including 60 boys and 47 girls with a mean age of 11.9 years who comprise the study group. Mean weight was 30 kg. at transplantation, and 32 and 75 patients weighed less than 20 and 20 or more kg., respectively. All 107 patients were treated with cyclosporine or tacrolimus based immunosuppression, including methylprednisolone and azathioprine or mizoribine. Living related and cadaveric renal transplantation was performed in 92 and 15 cases, respectively. The extraperitoneal technique was performed in all recipients, even in low weight children. The aorta and inferior vena cava, common iliac artery and vein or hypogastric artery and external vein were used for vascular anastomosis depending on recipient size. The ureter was anastomosed to the bladder via a modification of Paquin's method or an extravesical technique.

RESULTS

During observation 7 surgical complications (6.5%) developed, including ureteral stricture, ureteral necrosis, renal artery stenosis, lymphocele, subcapsular hematoma, bladder leakage and significant vesicoureteral reflux to the graft in 1 patient each. There were no gastrointestinal complications. One patient with ureteral necrosis and 1 with subcapsular hematoma required surgical repair, and 1 underwent laparoscopic fenestration of a lymphocele. One patient with ureteral stricture and 1 with bladder leakage were treated conservatively, while another underwent ureteroneocystostomy. Overall only 1 graft (1%) was lost to a surgical complication (renal artery stenosis).

CONCLUSIONS

The incidence of surgical complications of the extraperitoneal technique in pediatric renal transplant patients was low (6.5%) and seems to be acceptable. The extraperitoneal technique did not cause any gastrointestinal complications, which seems to be its greatest advantage. The extraperitoneal technique may be used safely even in low weight children.

Effect of GR144053, a fibrinogen-receptor antagonist, on thrombus formation and vascular patency after thrombolysis by tPA in the injured carotid artery of the hamster

The antithrombotic effect of GR144053, which inhibits platelet aggregation by binding to the fibrinogen receptor (glycoprotein IIb/IIIa), was investigated in vitro and in vivo by using hamsters. This compound inhibited the platelet aggregation induced by adenosine diphosphate (ADP; 2.5 microM) with a mean inhibitory concentration (IC50) value of 2.2 +/- 0.4 x 10(-5) M. Vascular injury was inflicted in one carotid artery by using a modified catheter to produce endothelial denudation. In the control group, arterial blood flow was interrupted 4.4 +/- 2.3 min (n = 12) after the injury. When GR144053 continuously infused intravenously at doses of 0 (saline) 0.1, 0.3, and 1.0 mg/kg/h (n = 8, each), the time that elapsed before the vessel became completely obstructed was prolonged in a dose-dependent manner. In separate experiments, reperfusion could be obtained by continuous infusion of tissue-type plasminogen activator (tPA; 0.52 mg/kg) starting 30 min after the initiation of thrombus formation. When GR144053 (0.3 and 1.0 mg/kg/h) was infused in addition to tPA, the incidence of reperfusion and the later patency of the reperfused artery were much improved as compared with tPA alone. The bleeding time at the end of tPA infusion was significantly prolonged in the presence of the highest dose of GR144053. Next, neointima formation was evaluated 2 weeks after the vascular injury. When GR144053 (0.3 mg/kg/h) was continuously infused i.v. by an implanted osmotic pump for 14 days, the neointimal area was significantly reduced. In separate hamsters, the proliferating index of smooth muscle cells (SMCs) by using bromodeoxyuridine (BrdU) was investigated, and treatment with both tPA and GR144053 significantly decreased the SMC proliferation index in vivo. However, in the in vitro experiments using a hamster SMC line, GR144053 did not have an inhibitory effect on SMC proliferation. These findings suggest that GR144053 inhibits platelet activation on the injured artery and improves vascular patency after thrombolysis with tPA, which furthermore results in suppression of neointima formation.

[A clinicopathological study of recurrent IgA nephropathy following renal transplantation]

The present study was conducted to examine the clinicopathological features of recurrent IgA nephropathy (IgAN) following renal transplantation. Serial renal biopsies were performed regularly at 0-hour, 1-hour and 2-hours, and 39 episode biopsies were carried out when patients had increased serum creatinine levels and proteinuria. In 49 renal allograft recipients with IgAN, 12 patients were proved to be recurrent IgAN (24.5%). There was a significantly increased five- and ten-year risk of graft loss in the renal allograft recipients with biopsy-proved recurrent IgAN. Graft survival in 49 renal allograft recipients with IgAN was worse (68.8% at 5 years and 40.4% at 10 years) than that in 997 whole transplants (80.7% at 5 years, and 67.7% at 10 years). We found significant differences in the prevalence of HLA-DR4 (66.7%) and BW35 (25%) in the renal allograft recipients with recurrent IgAN when compared with normal healthy subjects. The renal allograft recipients with recurrent IgAN had a high incidence of proteinuria (8/12), hypertension (9/12) and renal dysfunction of less than 50 ml/min (7/12). Mean hemodialysis duration before renal transplantation in recurrent IgAN transplants was 12.5 months, which was shorter than in those without recurrent IgAN. Histopathological studies revealed that renal lesions due to IgAN frequently appeared in the renal allograft recipients with recurrent IgAN. Taken together, these findings suggest that donor-recipient matching may be carefully reconsidered, and recurrent IgAN after renal transplantation must be treated with effective immunosuppressive therapy.

A G.U base pair in the eukaryotic selenocysteine tRNA is important for interaction with SePF, the putative selenocysteine-specific elongation factor

In Escherichia coli, selenocysteine biosynthesis and incorporation into selenoproteins requires the action of four gene products, including the specialized selenocysteine tRNA(Sec) and elongation factor SELB, different from the universal EF-Tu. In this regard, the situation is less clear in eukaryotes, but we previously reported the existence of SePF, a putative SELB homologue. The secondary structure of the tRNA(Sec) differs slightly in eukaryotes, due to a change in the lengths of several stems. Two non-Watson-Crick base pairs, G5a x U67b and U6 x U67, reside in the acceptor stem and are conserved in the course of evolution. Since it has already been reported that changing them to Watson-Crick base pairs did not affect the serylation or selenylation levels of tRNA(Sec), we asked whether these non-Watson-Crick base pairs are required for the interaction with SePF. To this end, tRNA(Sec) variants carrying Watson-Crick changes at these positions were tested for their ability to maintain the interaction with SePF. In these assays, the tRNA(Sec)-SePF interaction was determined by the protective action it confers against hydrolysis of the amino acid ester bond, under basic conditions. All the changes introduced at U6 x U67 did not significantly affect the interaction. Interestingly, however, the G5a x U67b to G5a-C67b substitution was sufficient, by itself, to lead to unprotection of the ester bond. Therefore, our finding strongly suggests that SePF is unable to interact with a tRNA(Sec) mutant version carrying a Watson-Crick G5a-C67b instead of the wild-type G5a x U67b base pair, establishing that G5a x U67b constitutes a structural determinant for SePF interaction.

Modulation of the growth of Plasmodium falciparum in vitro by protein serine/threonine phosphatase inhibitors

To elucidate the physiological roles of the protein serine/threonine phosphatases of P. falciparum, first we identified and characterized phosphatase activities of Plasmodium falciparum enzymologically and pharmacologically. We have demonstrated that P. falciparum possesses phosphatase-1-like activities predominantly over phosphatase-2A-like activities, while erythrocytes possess mainly phosphatase-2A-like activities. Then, we examined the effects of okadaic acid and calyculin A, potent inhibitors of protein phosphatase 1 and 2A, on the growth of P. falciparum in vitro. Both of the drugs inhibited parasite growth dose dependently. The manner of growth inhibition by calyculin A and okadaic acid suggested that these drugs inhibit parasite growth mainly by inhibiting parasite phosphatase-1-like activities. Both drugs were shown to inhibit the growth of three different developmental stages of parasites--ring forms, trophozoites, and schizonts--and inhibit trophozoites the most. This is the first report on P. falciparum protein serine/threonine phosphatase activities, which are essential to regulate the erythrocytic stage of parasite growth.

Isolation of a MX-guanosine adduct formed at physiological conditions

3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a highly potent mutagen present in chlorine-disinfected drinking water, was allowed to react with adenosine, guanosine, and cytidine in aqueous solutions. HPLC analyses, with detection at 254 and 310 nm, showed that a clearly detectable base adduct was formed in the reaction with guanosine. This substance was isolated by C18 column chromatography and characterized by UV absorbance, 1H NMR spectroscopy, and mass spectrometry. The compound was identified as 10-formyl-1, N2-benzoquinone propenoguanosine (I), and the yield was estimated to be approximately 0.1% in reactions performed at pH 7.4 and 37 degrees C.

Phosphorylation of vimentin by Rho-associated kinase at a unique amino-terminal site that is specifically phosphorylated during cytokinesis

We found that vimentin, the most widely expressed intermediate filament protein, served as an excellent substrate for Rho-associated kinase (Rho-kinase) and that vimentin phosphorylated by Rho-kinase lost its ability to form filaments in vitro. Two amino-terminal sites on vimentin, Ser38 and Ser71, were identified as the major phosphorylation sites for Rho-kinase, and Ser71 was the most favored and unique phosphorylation site for Rho-kinase in vitro. To analyze the vimentin phosphorylation by Rho-kinase in vivo, we prepared an antibody GK71 that specifically recognizes the phosphorylation of vimentin-Ser71. Ectopic expression of constitutively active Rho-kinase in COS-7 cells induced phosphorylation of vimentin at Ser71, followed by the reorganization of vimentin filament networks. During the cell cycle, the phosphorylation of vimentin-Ser71 occurred only at the cleavage furrow in late mitotic cells but not in interphase or early mitotic cells. This cleavage furrow-specific phosphorylation of vimentin-Ser71 was observed in the various types of cells we examined. All these accumulating observations increase the possibility that Rho-kinase may have a definite role in governing regulatory processes in assembly-disassembly and turnover of vimentin filaments at the cleavage furrow during cytokinesis.

Efficacy of oral magnesium administration on decreased exercise tolerance in a state of chronic sleep deprivation

We have previously reported that chronic sleep deprivation causes a deficiency of intracellular magnesium (Mg) and decreased exercise tolerance. The aim of this study was to clarify whether oral administration of Mg could be effective in restoring the exercise tolerance that is decreased by chronic sleep deprivation. A bicycle ergometer cardiopulmonary exercise test was performed by 16 healthy volunteers (mean age 21.9 years). They were divided into 2 groups: 8 received doses of 100 mg of Mg orally per day for 1 month (Mg group) and the remaining 8 received no Mg and served as the control group. The study conditions were designed as follows: (1) the usual state (good sleep); and (2) the sleep-deprived state (sleeping time up to 60% less than the usual state for 1 month). The ratio of intracellular Mg content of the sleep-deprived state to the usual sleep state was significantly higher in the Mg group (p<0.05) than the untreated control group. There was no difference between the sleep-deprived state and the usual state with regard to anaerobic threshold and peak oxygen uptake in the Mg group, whereas both of these decreased in the sleep-deprived state in the control group. These results indicate that decreased exercise tolerance observed in the sleep-deprived state could be improved by oral Mg administration.

Multiple inhibition of platelet activation by aurintricarboxylic acid prevents vascular stenosis after endothelial injury in hamster carotid artery

Activated platelets are instrumental in restenosis due to their role in thrombus formation. Aurintricarboxylic acid (ATA) has been reported to prevent platelet activation by inhibiting von Willebrand factor binding to platelet glycoprotein (GP)Ib. We investigated the effects of ATA in vitro and in vivo in hamsters. ATA inhibited the in vitro platelet aggregation induced by ADP, botrocetin and thrombin, but not by collagen. The IC50 values during the ex vivo platelet aggregation by ADP, botrocetin and thrombin were 8.2 +/- 1.8 microM, 0.9 +/- 0.4 microg/ml and 2.4 +/- 0.8 unit/ml, respectively. The platelet retention time to collagen-coated beads of hamster blood samples was inhibited by ATA (0.1, 0.3 and 1.0 mg/kg per hour) in a dose-dependent manner. Continuous administration of ATA (0, 0.1, 0.3, 1.0, 3.0 and 10.0 mg/kg per h) via an infusion pump produced dose-dependent antithrombotic effects: the time to occlude the carotid artery after vascular injury with a modified catheter was prolonged. Only when infused at doses of 3.0 and 10.0 mg/kg per hour, bleeding times were significantly prolonged. The continuous treatment with ATA (1.0 mg/kg per h) using a 2ML1 Alzet infusion pump for 2 weeks, resulted in a decrease in neointimal area by 22.2 +/- 6.8% when measured 2 weeks after injury induction. DNA synthesis using DDT1MF2 hamster SMCs was decreased by ATA in a dose-dependent manner. ATA reduced the number of platelets adhering on the injured area, as detected by electron microscopy. These results indicated that treatment with ATA inhibited platelet adhesion but also SMC proliferation. These observations may explain the effect of ATA on neointima formation.

Inhibition of cyclin D1 expression and induction of apoptosis by inostamycin in small cell lung carcinoma cells

Previously, we demonstrated that inostamycin, an inhibitor of phosphatidylinositol turnover, caused cell cycle arrest at the G1 phase, inhibiting the expression of cyclins D1 and E in normal cells. In the present study, we examined the effects of inostamycin on cell cycle progression and apoptosis in human small cell lung carcinoma Ms-1 cells. Treatment of exponentially proliferating Ms-1 cells with low concentrations of inostamycin caused cells to accumulate in the G1 phase. We found that inostamycin decreased cyclin D1, and increased cyclin-dependent kinase inhibitors such as p21WAF1 and p27KIP1 in Ms-1 cells. On the other hand, higher concentrations of inostamycin induced morphological apoptosis and DNA fragmentation in Ms-1 cells without affecting the expression of p53, Bcl-2 and Bax. Inostamycin-induced apoptosis was suppressed by an inhibitor of caspase-3, and a 17 kDa fragment of activated caspase-3 was detected following inostamycin treatment. Therefore, caspase-3(-like) would appear to be involved in inostamycin-induced apoptosis. On the other hand, an inhibitor of caspase-3(-like) proteases did not affect the inhibitory effect of inostamycin on cyclin D1 expression, suggesting that caspase-3(-like) proteases were not responsible for inostamycin-induced G1 arrest.