Images in cardiothoracic surgery. Persistent fifth aortic arch.
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Aorta, Thoracic↗
Biomedical subjects
Masanobu Maeda
Publications and source records attributed to Masanobu Maeda.
Two-stage procedure for pulmonary vascular obstructive disease in Down syndrome with congenital heart disease.
BACKGROUND: Down syndrome patients are characterized by early progression of pulmonary vascular obstructive disease because of insufficient thickness of the pulmonary arterial media. For those with congenital heart disease (CHD) associated with pulmonary hypertension (PH), a 2-stage procedure of pulmonary artery banding (PAB) and then intracardiac repair (ICR) in early infancy is performed to prevent such pulmonary vascular diseases in early infancy. METHODS AND RESULTS: The subjects were 16 patients with Down syndrome who underwent lung biopsy during PAB and ICR. PAB was planned to be performed in early infancy and ICR approximately 1 year later. Efficacy of the 2-stage procedure was retrospectively examined with reference to pulmonary vascular disease and pulmonary diseases. The index of pulmonary vascular disease at PAB fulfilled the indication for ICR, and it was significantly lower at ICR than at PAB (p=0.0469); furthermore, PAB prevented progression of pulmonary diseases. CONCLUSIONS: The results of the lung biopsies support the safety of the 2-stage procedure and show that it is effective for Down syndrome patients with CHD and PH.
Arterial Occlusive Diseases↗
Comparison of response to 17 beta-estradiol and 17 beta-trenbolone among three small fish species.
Three small fish species, medaka (Oryzias latipes), fathead minnow (Pimephales promelas), and zebrafish (Danio rerio), were exposed to an estrogen, 17 beta-estradiol (E2), and an androgen, 17 beta-trenbolone (TB), for 21 d under flow-through conditions to compare the susceptibility among these three small fish species to the substances. Effects on gross morphology, including secondary sex characteristics and gonadosomatic index, as well as on blood or liver vitellogenin (VTG) levels were assessed. In E2 exposures, significant increases in estrogenic activity were observed in both sexes of all three fish species. The lowest-observed-effect concentrations (LOECs) of E2 for VTG induction in males of medaka, fathead minnow, and zebrafish were less than or equal to 8.94, 28.6, and 85.9 ng/L, respectively. In TB exposures, we observed masculinization of secondary sex characteristics in females as a result of the androgenic activity of TB in medaka with a LOEC of 365 ng/L and in fathead minnow with a LOEC of 401 ng/ L. We also found VTG reduction in females of all three fish species. These results suggest that the susceptibility of medaka to estrogenic chemicals may be higher than those of fathead minnow and zebrafish and that the susceptibility of medaka to androgenic chemicals may be almost equal to that of fathead minnow in the 21-d fish assay.
Animals↗
Deletion of the kinase domain from death-associated protein kinase enhances spatial memory in mice.
Death-associated protein kinase (DAPK) is a Ca2+/calmodulin-dependent serine/threonine kinase that is thought to mediate apoptosis. DAPK is highly expressed in hippocampal neurons which are essential elements for memory formation. To examine if DAPK is implicated in spatial learning and memory, both wild-type and DAPK-mutant mice were subjected to Morris water maze tests. DAPK-mutant mice were generated by deleting 74 amino acids from the catalytic kinase domain of DAPK, and were used to investigate roles of the DAPK kinase domain in regulating spatial memory. Both mutant and wild-type mice were able to learn the water maze tasks to locate a hidden escape platform. In the first probe test, mutant mice showed a more precise memory for platform position compared to wild-type mice. In the reversal training in which the platform was located opposite from the original position, DAPK-mutant mice exhibited superior spatial learning compared to wild-type mice. DAPK-mutant mice also showed a more precise memory than their wild-type littermates in the probe trial of reversal test. Thus, the present results revealed crucial implications of DAPK in regulating spatial memory in mice.
Animals↗
[Model lectures in physiology education].
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Animals↗
Hypotensive effect of des-acyl ghrelin at nucleus tractus solitarii of rat.
Ghrelin is a gut-brain peptide and its endocrine activities are mediated by GH secretagogue receptor (GHSR)-1a. Des-acyl ghrelin does not activate GHSR-1a and is devoid of endocrine activities. While the microinjection of ghrelin into rat nucleus tractus solitarii (NTS) elicited hypotensive effects, this was not the case upon injection into GHSR-expressing rostral ventrolateral medulla or caudal ventrolateral medulla. To make clear the reason of the discrepancy between receptor distribution and neuronal responses, we examined the cardiovascular response of rats microinjected with des-acyl ghrelin into NTS. Intra-NTS injection of des-acyl ghrelin significantly reduced mean arterial pressure and heart rate. The hypotensive and bradycardic activity evoked by des-acyl ghrelin was not significantly different from that of native ghrelin. These results suggest that des-acyl ghrelin contribute to the regulation of cardiovascular control and that a receptor other than GHSR-1a exists in NTS.
Animals↗
Direct in vivo protein transduction into a specific restricted brain area in rats.
Attempts at protein transduction into specific restricted brain areas have remained unsuccessful. We attempted targeted, direct in vivo protein transduction by microinjecting beta-galactosidase (beta-gal) with hemagglutinating virus of Japan envelope (HVJ-E) vector into the rat nucleus tractus solitarius (NTS). The medulla oblongata including the NTS was removed 6h post-injection and cryostat sections were histochemically stained to detect beta-gal enzymatic activity. beta-gal-positive cells were present in these sections as was beta-gal activity determined by colorimetric analysis. beta-gal-positive cells were not present in the rats microinjected only beta-gal protein without HVJ-E vector. Our findings suggest that direct in vivo protein transduction into specific restricted brain areas is possible. The type of targeted delivery system we present may have wide applications in the administration of therapeutic proteins to the central nervous system.
Animals↗
Fish full life-cycle testing for 17beta-estradiol on medaka (Oryzias latipes).
We studied the chronic effects of 17beta-estradiol (E2) on the reproductive status of medaka (Oryzias latipes) over two generations under continuous exposure to assess its hazard on this species. The exposure of parental (F0) medaka to E2 was begun on embryos within 12 h postfertilization and continued for up to 101 d; the assessment endpoints included embryological development, hatching, posthatch survival, growth, sexual differentiation, reproduction, and hepatic vitellogenin (VTG) levels under flow-through exposure to E2 at each mean measured concentration of 0.939, 2.86, 8.66, 27.9, and 92.4 ng/L. Eggs (F1) spawned from the F0 fish at 98, 99, and 100 d posthatch were also examined for hatchability, survival after hatching, growth, sexual differentiation, and hepatic VTG level until 59 d posthatch. In the F0 medaka, no concentration-related effect of E2 was observed on hatching, posthatch mortality, and growth. However, we observed abnormal sex differentiation, induction of VTG, and reproductive impairment in a dose-dependent manner. The lowest-observed-effect concentration and no-observed-effect concentration of E2 for these effects were 8.66 and 2.86 ng/L, respectively. In the F1 medaka treated with E2 at < or = 8.66 ng/L, however, dose-dependent effects were not observed in any parameter. The results indicate that E2 can have significant effects on reproductive potential of medaka at concentrations as low as 8.66 ng/L, suggesting that the ecological risk of E2 is higher than that of weak estrogens, such as nonylphenol and octylphenol.
Animals↗
The kinase domain of death-associated protein kinase is inhibitory for tubulointerstitial fibrosis in chronic obstructive nephropathy.
Death-associated protein kinase (DAPK) is a Ca2+/calmodulin-dependent serine/threonine kinase that is thought to mediate apoptosis. We have shown that the kinase domain of DAPK is crucial for the induction of renal tubular cell apoptosis in chronic obstructive uropathy (COU) created by unilateral ureteral ligation. DAPK-mutant mice, generated by deletion of 74 amino acids from the catalytic kinase domain, were used to investigate the role of the DAPK kinase domain in renal fibrosis following COU. Interstitial collagen and alpha-smooth muscle actin (alpha-SMA) expressions in situ were compared between obstructed kidneys in wild-type and mutant mice. As a result, tubulointerstitial fibrosis, as quantified by interstitial collagen expression, was significantly augmented in mutant kidneys compared with wild-type kidneys following COU. Furthermore, deletion of the kinase domain from DAPK significantly increased the appearance of alpha-SMA-positive myofibroblasts in the renal interstitium during COU. Thus, our results suggest that the kinase domain deleted by gene targeting plays a suppressive role for the development of renal fibrosis through inhibition of the tubular epithelial-to-mesenchymal transition in a mouse model of COU.
Actins↗
STAT6 deficiency inhibits tubulointerstitial fibrosis in obstructive nephropathy.
To elucidate the contribution of signal transducer and activator of transcription (STAT) 6 to the pathophysiology of chronic renal injury, STAT6-/- mice were subjected to unilateral ureteral ligation together with wild-type control mice. STAT6-/- kidneys had more apoptotic cells and a greater influx of F4/80-positive cells than wild-type kidneys following ureteral obstruction. There was a much larger alpha-smooth muscle actin-positive area in STAT6-/- kidneys than in wild-type kidneys after ureteral ligation. However, renal fibrosis, as quantified by Masson-Trichrome staining, was not significantly exaggerated in STAT6-/- kidneys compared with wild-type kidneys. The accumulation of collagen I was significantly less in STAT6-/- kidneys than in wild-type kidneys. These observations indicate that the STAT6 signal transduction pathway exerts a protective role on renal cell apoptosis in chronic obstructive uropathy. Our findings also suggest that the STAT6 pathway may have a promotive effect on renal fibrosis by activating collagen synthesis following ureteral obstruction.
Actins↗
Down-regulation of dopamine transporter and abnormal behavior in STAT6-deficient mice.
To determine the role of STAT6 transcription factors in brain function, we performed a battery of mouse behavioral analyses of STAT6-deficient mice and made comparisons with wild-type mice. STAT6-deficient mice were significantly more hyperactive in the final two blocks of an open field test, indicating abnormal habituation in completing the task. Two learning tasks, a water maze and a passive avoidance test, were mastered by STAT6-deficient mice as effectively as the wild-type. RT-PCR analysis suggested that the levels of dopamine transporter (DAT) mRNA may be lower in the midbrain of the mutant. In agreement with the finding, subsequent Western blotting and immunohistochemical analysis demonstrated lower levels of DAT protein in the mutant striatum. These results lead to the proposal that, in addition to being a pivotal transcription factor in the immune system, STAT6 may be crucially implicated in mouse behavior by modulating the expression of neuronal genes such as DAT.
Animals↗
Semaphorin 4A induces growth cone collapse of hippocampal neurons in a Rho/Rho-kinase-dependent manner.
Semaphorins are a family of secreted and membrane-bound proteins, known to control axonal pathfinding. It was recently demonstrated that Semaphorin 4A (Sema4A) is crucially involved in immune cell activation. However, the role of Sema4A in the nervous system has not yet been clarified. To examine if Sema4A can function as a chemo-repulsive cue to growth cones of developing hippocampal neurons, a growth cone collapse assay with recombinant Sema4A was performed in primary hippocampal neurons cultured from E17 mice. In these primary hippocampal neurons, Sema4A induced a significant growth cone collapse as compared with the culture without Sema4A. The Sema4A-induced growth cone collapse could be blocked by Y-27632, a Rho-kinase inhibitor. Furthermore, immunocytochemical analysis with antibodies against Sema4A demonstrated the binding of recombinant Sema4A to the growth cones of hippocampal neurons. Thus, our data indicated that Sema4A could function as a chemo-repulsive cue by activating a receptor whose signal is transmitted to Rho-kinase and induced growth cone collapse of hippocampal neurons.
Animals↗
Deletion of the kinase domain from death-associated protein kinase attenuates p53 expression in chronic obstructive uropathy.
Death-associated protein kinase (DAPK) is a Ca(2+)/calmodulin-dependent serine/threonine kinase that is thought to mediate apoptosis. We previously showed that the kinase domain of DAPK is crucial for the induction of renal tubular cell apoptosis in chronic obstructive uropathy (COU) caused by a unilateral ureteral ligation. Here, we used DAPK-mutant mice, generated by the deletion of 74 amino acids from the catalytic kinase domain, to investigate the role of the DAPK kinase domain in regulating the p53 level following COU. The p53 expression levels in obstructed kidneys of wild-type and mutant mice were determined during the course of COU. Western blot analysis revealed that the p53 protein levels were significantly increased at 5 days after a ureteral ligation. This increase in the p53 level was significantly attenuated in mutant kidneys compared to wild-type kidneys. The obstructed kidneys of DAPK-mutant mice showed a significantly lower number of p53-expressing renal tubule cells than wild-type mice. These results are consistent with the hypothesis that DAPK stabilizes p53 protein in response to apoptosis-inducing stimuli. Thus, the present results suggest that the DAPK kinase domain is crucial for stabilizing p53 protein in renal tubular cell apoptosis in a mouse model of COU.
Animals↗
Reduced prepulse inhibition of startle in STAT6-deficient mice.
To determine the role of STAT6 transcription factors in brain function, we performed a battery of mouse behavioral analyses of STAT6-deficient mice. We recently showed that STAT6-deficient mice displayed increased locomotor activities and had reduced levels of dopamine transporter (DAT) expression in the striatum. To further examine the behavioral effects of STAT6 deficiency, we subjected STAT6-deficient mice to behavior task testing prepulse inhibition (PPI) of the auditory startle response. In acoustic prepulse conditions, STAT6-deficient mice displayed significantly lower levels of PPI in acoustic startle than did wild-type mice, indicating their sensorimotor gating deficits. Thus, STAT6 transcription factors may be crucially implicated in sensorimotor gating by modulating the expression of several genes, including DAT in brain neurons.
Acoustic Stimulation↗
Deletion of the kinase domain in death-associated protein kinase attenuates tubular cell apoptosis in renal ischemia-reperfusion injury.
Death-associated protein kinase (DAPK) is a calcium/calmodulin-dependent serine/threonine kinase localized to renal tubular epithelial cells. To elucidate the contribution of DAPK activity to apoptosis in renal ischemia-reperfusion (IR) injury, wild-type (WT) mice and DAPK-mutant mice, which express a DAPK deletion mutant that lacks a portion of the kinase domain, were subjected to renal pedicle clamping and reperfusion. After IR, DAPK activity was elevated in WT kidneys but not in mutant kidneys (1785.7 +/- 54.1 pmol/min/mg versus 160.7 +/- 60.6 pmol/min/mg). Furthermore, there were more TUNEL-positive nuclei and activated caspase 3-positive cells in WT kidneys than in mutant kidneys after IR (24.0 +/- 5.9 nuclei or 9.4 +/- 0.6 cells per high-power field [HPF] versus 6.3 +/- 2.2 nuclei or 4.4 +/- 0.7 cells/HPF at 40 h after ischemia). In addition, the increase in p53-positive tubule cells after IR was greater in WT kidney than in mutant kidneys (9.9 +/- 1.4 cells/HPF versus 0.8 +/- 0.4 cells/HPF), which is consistent with the theory that DAPK activity stabilizes p53 protein. Finally, serum creatinine levels after IR were higher in WT mice than in mutant mice (2.54 +/- 0.34 mg/dl versus 0.87 +/- 0.24 mg/dl at 40 h after ischemia). Thus, these results indicate that deletion of the kinase domain from DAPK molecule can attenuate tubular cell apoptosis and renal dysfunction after IR injury.
Animals↗
Stroke recurrence within the first year following cerebral infarction--Tottori University Lacunar Infarction Prognosis Study (TULIPS).
OBJECTIVES: To identify determinants of recurrence after ischemic stroke in the Japanese population. MATERIALS AND METHODS: We enrolled 885 patients with acute ischemic stroke that had been admitted to our community hospitals. A total of 831 cases were followed for 1 year after the index stroke. Patients were assigned to one of the ischemic stroke subtype groups based on the NINDS Stroke Data Bank criteria. RESULTS: Rates of stroke recurrence were significantly different among stroke subtype groups: 14.4% in cardioembolic infarction, 7.3% in atherothrombotic infarction (ATI), 6.2% in lacunar infarction (LI) and 7.8% in infarction of uncertain cause. Previous history of stroke was the predictor of stroke recurrence for the groups of ATI and LI patients, and diabetes mellitus was the predictor of recurrence for the group of LI patients. CONCLUSION: The rate of recurrence and risk factors for stroke recurrence are different by stroke subtypes.
Aged↗
Fish full life-cycle testing for androgen methyltestosterone on medaka (Oryzias latipes).
Abstract-We studied the chronic effects of methyltestosterone (MT) on reproductive status of medaka (Oryzias latipes) over two generations under continuous exposure to verify the applicability of the fish full life-cycle test (FFLC) for this androgen with this species. The exposure of parental (F0) medaka to MT was begun on embryos within 12 h postfertilization and continued for up to 101 d; assessment endpoints included embryological development, hatching, posthatch survival, growth, sexual differentiation, reproduction, and hepatic vitellogenin (VTG) levels under flow-through exposure to MT at each mean measured concentration of 0.35, 1.09, 3.29, 9.98, and 27.75 ng/L. Eggs (F1) spawned from the F0 fish at 98, 99, and 100 d posthatch were examined for hatchability, survival after hatching, growth, sexual differentiation, and hepatic VTG level until 60 d posthatch. In the FFLC with medaka, MT induced masculinization of both secondary sex characteristics and gonads. We observed that all F0 fish in the 27.75-ng/L treatment group showed male secondary sex characteristics in which no fish with ovary could be discerned. Several fish with ovaries in F0 and F1 generations treated with 9.98 ng/L showed male secondary sex characteristics. We also observed swollen abdomens in the F0 and F1 female fish in the 9.98-ng/L treatment group. These swollen abdomens were induced by enlarged ovaries and were accompanied with declined fecundity and fertility in the F0 generation. These results indicate that MT reduces the reproductive potential of medaka and that the FFLC with this species is applicable to the evaluation of androgens.
Animals↗
Reduced expression of death-associated protein kinase in human uterine and ovarian carcinoma cells.
The expression of the death-associated protein kinase (DAPK) protein and promoter methylation in 11 human uterine and ovarian carcinoma cell lines originally established from histopathologically-different carcinoma tissues were examined to investigate the relationship between DAPK and carcinogenesis in female reproductive tissues. The 11 cell lines included three cervical carcinomas, three endometrial carcinomas and five ovarian carcinomas. Western blot analysis showed no detectable expression of DAPK protein in 4 cell lines (ME180, HOKUG, MCAS and OVK-18) while moderate levels of DAPK protein were readily detected in normal human endometrium, and normal murine uterus and ovary. Methylation-specific PCR of the 11 cell lines revealed that 5 carcinoma cell lines (ME180, HOKUG, MCAS, OVK-18 and HEC-1) expressed hypermethylated promoters in the DAPK genes, while DAPK promoters in the other 6 carcinoma cell lines remained unmethylated. These results indicate that DAPK protein expression is reduced or silenced in some human uterine and ovarian carcinoma cells by methylation of the DAPK gene promoter region. Therefore, reduced DAPK expression and methylation of the DAPK promoter may be involved in carcinogenesis of human uterine and ovarian tissues.
Animals↗