Oral administration of geranylgeranylacetone protects rat livers from warm ischemic injury.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to A Goto.
Explore the source record for details and available documents.
1. The effects of oestrogens on action potential and membrane currents were examined in single guinea-pig atrial myocytes. 2. 17Beta-estradiol (3-10 microM) shortened the action potential duration without significant changes in the resting membrane potential. E-4031 (1 microM) markedly prolonged the action potential duration and induced early afterdepolarization, and 17beta-estradiol (10 microM) abolished it. 3. When cells were perfused in isoproterenol-containing solution, action potentials due to abnormal automaticity caused by membrane depolarization developed, and were also inhibited by 17beta-estradiol. 4. Under voltage clamp conditions, the voltage-dependent Ca2+ currents consisted of both T-(I(Ca,T)) and L-type (I(Ca,L)). 17Beta-estradiol reduced I(Ca,L) concentration-dependently, while it (10 microM) suppressed I(Ca,T) only by approximately 10%. 17Beta-estradiol did not affect time courses of I(Ca,L) inactivation, but it shifted the steady-state inactivation curve to more negative potentials. 5. 17Beta-estradiol (10 microM) did not affect the time-dependent K+ current (I(K)), referred to as I(Kr) and I(Ks) and inwardly rectifying K+ current. However, 17beta-estradiol (30 microM) or diethylstilbestrol (10 microM) inhibited K+ currents. 6. DES and ethinylestradiol (EES) also suppressed I(Ca,L), but testosterone and progesterone failed to inhibit I(Ca,L) The potency of the inhibitory effect on I(Ca,L) was DES> EES> 17beta-estradiol. 7. 17Beta-estradiol and DES also inhibited the cyclic AMP-enhanced I(Ca,L), but cyclic GMP in the pipette or pretreatment of L-NAME could not block the effects of oestrogen on I(Ca,L). 8 These results suggest that oestrogen specifically has antiarrhythmic effects, possibly by acting the L-type Ca2+ channels. The antiarrhythmic effects of oestrogens may contribute to the cardioprotective actions of oestrogens.
A Drosophila gene (KAZ1), mapped to cytological position 61A1-2 on chromosome 3, has been cloned and found to encode multiple splice variants of Kazal-type serine protease inhibitor-like proteins. KAZ1 consists of five exons and four alternatively retained introns to produce six transcripts of type AB, C1, C2, C3, D and E. The AB transcript contains two ORFs, of which the upstream one produces a polypeptide alpha, which has a mitochondrial sorting signal. Localization to mitochondria was confirmed by expression in COS1 cells. The downstream ORF is shared partially with type C1, C2, C3, D and E transcripts and produces polypeptides beta, gamma, delta and epsilon when expressed in Drosophila cells. Type C1, C2 and C3 transcripts differ only in the 5'-noncoding sequence and thus all produce type gamma. Polypeptides gamma and epsilon have a signal sequence at their N-termini and are secreted into the medium while beta and delta lack this sequence and remain in the cytoplasm. Isoforms beta and epsilon share a common C-terminal sequence distinct from that shared by polypeptides gamma and delta. The N-terminal sequences of isoforms beta to epsilon contain a PEST region which could induce rapid intracellular degradation of isoforms beta and delta. Sequence analysis of the Kazal-type domain suggests a similar folding pattern as observed for rhodniin and SPARC/BM-40. Northern analysis and in situ hybridization showed that the type C3 transcript is predominant and the expression is highest in midgut at larval stage.
As in other clitellate annelids, embryonic development in the oligochaete Tubifex is characterized by the generation of five bilateral pairs of teloblasts (designated M, N, O, P and Q), which serve as embryonic stem cells to produce germ bands on either side of the embryo. A large part of the tissues comprising body segments has been assigned to the progenies of the teloblasts; however, the developmental fate of each teloblast has been inferred only from its initial position in the embryo. In the present study, the fate of the progenies of each teloblast was followed by means of intracellular injection of a tracer enzyme, horseradish peroxidase. Cell fate maps for teloblasts in the Tubifex embryo were constructed. M teloblasts gave rise to nearly all of the mesodermal tissues, which included circular and longitudinal muscles, coelomic walls, nephridia (in segments VII and VIII) and primordial germ cells (in segments X and XI). Although few in number, M teloblasts also contributed cells to the ventral ganglion. Similarly, each of the ectoteloblasts, N, O, P and Q, made a topographically characteristic contribution to the ectodermal tissues such as the nervous system (i.e. ganglionic cells and peripheral neurones) and epidermis, all of which exhibited a segmentally repeated distribution pattern. The P and Q teloblasts uniquely gave rise to additional ectodermal tissues, namely ventral and dorsal setal sacs, respectively. Furthermore, O teloblasts made a contribution to the nephridiopores in segments VII and VIII as well. These results confirm the previously held view that ectoteloblasts and mesoteloblasts are the main source of ectodermal and mesodermal segmental tissues, respectively, but also suggest that all of the teloblasts produce more types of tissue than has previously been thought.
The enzyme, thymidine phosphorylase (dThdPase) is identical to platelet-derived endothelial cell growth factor (PD-ECGF), which acts as a potent angiogenic factor. The present study immunohistochemically examined the expression of dThdPase in human colorectal mucosa, adenomas and carcinomas, as well as six cultured colorectal carcinoma cell lines, in terms of intratumoral microvessel density (IMVD) and P53 expression. Thymidine phosphorylase was observed in lymphocytes, fibroblasts and macrophages, as well as smooth muscle cells and Schwann cells in the peripheral nerve fibers. The dThdPase-positive stromal cells apparently outnumbered the normal epithelial cells, adenoma and carcinoma cells with dThdPase. Weak but obvious cytoplasmic immunoreactivity was noted in a few normal colonic epithelia, predominantly the upper surface area, while a few adenoma cells showed weak nuclear immunostaining for dThdPase in six (24%) of the 25 colonic adenomas. Expression of dThdPase was noted in 33 (73.3%) of the 45 Dukes A and B, 14 (51.9%) of the 27 Dukes C and 14 (56.0%) of the 25 Dukes D carcinomas. The mean IMVD was 84.0 +/- 26.2 in the 36 dThdPase-negative carcinomas and 97.9 +/- 31.6 in the 61 dThdPase-positive carcinomas, the value being significantly higher in the latter group (P < 0.05). The frequency of dThdPase expression was significantly lower in the P53-negative carcinomas than in the positive carcinomas (P < 0.05). Western blot analysis showed the highest expression of dThdPase in LoVo carrying the wild-type p53 gene, followed by Colo201, Colo320, DLD-11 and WiDr carrying the mutated gene. These results indicate that: (i) the main source of dThdPase is stromal cells, including lymphocytes and macrophages in both colorectal normal and carcinoma tissues; (ii) dThdPase may take part in the induction of intratumoral microvessels, regardless of tumor stage; and (iii) expression might be modulated by not only P53 but also other molecules.
BACKGROUND: Adrenomedullin (AM) is a newly discovered peptide that has a potent vasorelaxant activity. To investigate its potential roles in hypoxia-induced renal injury, we examined whether AM production in the kidney increased under hypoxic conditions. METHODS: The AM transcript levels in Madin-Darby canine kidney (MDCK) cells, rat vascular smooth muscle cells (VSMCs), and rat mesangial cells were assessed by Northern blot analyses under normoxic and hypoxic conditions. The AM peptide in culture media was measured by radioimmunoassay. The effects of hypoxia on accumulation of cAMP in VSMCs were also examined. The stability of AM transcripts under normoxic and hypoxic conditions was compared in the presence of actinomycin D. The effects of hypoxia on AM promoter activity was assessed by transient transfection assays using the AM promoter subcloned upstream of luciferase gene. RESULTS: The expression of AM transcripts increased significantly in MDCK cells, rat VSMCs, and rat mesangial cells under hypoxic conditions without changes in the stability of AM transcripts; however, the AM promoter activity under hypoxic was not elevated significantly. The accumulation of AM peptide in culture media also increased significantly under hypoxic conditions in MDCK cells (2.2 +/- 0.1 fmol/10(5) cells in normoxia vs. 3.5 +/- 0.3 fmol/10(5) cells in hypoxia, 6 hr after hypoxia induction, P < 0.001), and in rat VSMCs (5.5 +/- 0.3 fmol/10(5) cells in normoxia vs. 7.8 +/- 0.4 fmol/10(5) cells in hypoxia, 8 hr after hypoxia induction, P < 0.01). Under hypoxic conditions, cAMP levels in rat VSMCs increased significantly compared with those under normoxic conditions (13.3 +/- 1.4 pmol/well vs. 4.6 +/- 0.4 pmol/well, P < 0.01). CONCLUSIONS: Renal parenchymal cells as well as renal vessels may produce AM under hypoxic conditions.
BACKGROUND: We examined whether a high-cholesterol (HC) diet causes glomerulosclerosis in rats, and investigated the role of free radicals and lipid peroxidation in lipid-induced glomerulosclerosis. METHODS: The rats were given a normal diet, a HC diet, or a HC diet with antioxidants and radical scavengers. Serum levels of lipid, lipid peroxide (LOOH), urinary excretion of protein (UP), and urinary norepinephrine excretion (UNE) were measured. The glomerular sclerosing score was used to evaluate the renal injury. RESULTS: Blood pressure, total cholesterol, and LOOH were increased by a HC diet, as were UP and UNE. The HC diet induced renal injury. Treatment with superoxide dismutase, dimetylthiourea as a scavenger of hydroxyl radical (OH.), defferoxamine masilate as an iron chelator, or vitamin E inhibited the increases in blood pressure, LOOH, UP, and UNE, whereas total cholesterol was not affected. The production of superoxide anion (O2-.) by neutrophil and LOOH in the kidney was increased, and superoxide dismutase and hydrogen peroxide in the kidney were decreased. Almost all of these changes were attenuated by vitamin E; however, the O2-. production was not inhibited. OH. was increased by the HC diet, and it was normalized with the treatments. Furthermore, the sclerosing score was partially suppressed by the treatments. Ferric iron was stained in the proximal tubulus, and it was not observed in the treated rats. CONCLUSIONS: The data suggest that lipid peroxidation is involved in the pathogenesis of lipid-induced glomerulosclerosis and that O2-. and OH. may play a role in the process.
OBJECTIVE: To investigate the role of hypercholesterolemia in the regulation of blood pressure. SUBJECTS AND METHODS: We compared blood pressure responses to arithmetic stress and hand-grip tests in normotensive patients with hypercholesterolemia n = 15) and a mean (+/- SEM) age of 49 +/- 3 years, and normal cholesterolemic controls (n = 22) aged 48 +/- 1 years. Blood pressure and heart rate were measured throughout the tests. We examined the intracellular Ca2+ concentration in platelets with or without low-density-lipoprotein stimulation (2.9 nmol/l, 10 mg/ml). The plasma nitrite plus nitrate and cyclic GMP were determined before and at the end of each test to evaluate nitric oxide production and activity. RESULTS: Both tests showed that systolic/diastolic blood pressure was higher in the hypercholesterolemic patients than in the normal controls (stress test: 139 +/- 3/91 +/- 4 versus 127 +/- 2/80 +/- 3 mmHg, P < 0.01/P < 0.05; hand-grip test: 164 +/- 5/106 +/- 5 versus 144 +/- 3/88 +/- 3 mmHg, P < 0.01/P < 0.01). The intracellular Ca2+ concentration in platelets and the increase in response to low-density-lipoprotein stimulation were higher in the hypercholesterolemic patients (without stimulation: 72 +/- 3 versus 64 +/- 3 nmol/l, P < 0.01; with 2.9 nmol/l stimulation: 145 +/- 21 versus 89 +/- 6 nmol/l, P < 0.01). The increase in Ca2+ in response to 2.9 nmol/ml stimulation with low-density lipoprotein was positively related to the increase in mean blood pressure in response to the stress test (r = 0.56, P < 0.002). Nitric oxide production appeared to be increased in the hypercholesterolemic patients (65 +/- 5 versus 51 +/- 4 mmol/l, P < 0.05), and was not affected significantly by the tests. In contrast, cyclic GMP was lower in the patients and was increased significantly in the normal controls by the hand-grip test (P < 0.05). As a result, plasma cyclic GMP was lower in the patients (1.9 +/- 0.2 versus 2.5 +/- 0.1 nmol/l, P < 0.01). The ratio of plasma cyclic GMP to nitric oxide was also lower in the hypercholesterolemic patients at rest (P < 0.05), and at the end of the mental stress (P < 0.02) and hand-grip (P < 0.001) tests. CONCLUSIONS: Patients with hypercholesterolemia showed an exaggerated blood pressure response to both mental stress and exercise, even if resting blood pressure was normal. Increases in the intracellular Ca2+ concentration can contribute to these excessive responses. A disproportionately lower level of cyclic GMP to nitric oxide in plasma may also be involved in these abnormal responses.
OBJECTIVE: We recently reported that the renin-angiotensin system plays an important role in the progression of vascular and kidney injuries, even in Dahl salt-sensitive rats with volume-dependent hypertension. In this study, we investigated whether a high-salt diet increases susceptibility to kidney injury induced by angiotensin II in normotensive, uni-nephrectomized Sprague-Dawley rats, which mimics the condition of salt-volume repletion and blunted renin-angiotensin system. METHODS: The rats were fed either a low-salt (0.3% NaCl) or a high-salt (4% NaCl) diet and divided into five groups: two control groups with a low-salt or a high-salt diet without angiotensin II infusion (saline infusion), and three angiotensin II groups (angiotensin II infusion, 10 or 50 ng/kg per min with high-salt diet, 50 ng/kg per min with low-salt diet, subcutaneously). The rats were kept on these regimes for 8 weeks. The blood pressure was measured every week. Functional and morphological alterations in the kidney were assessed at the end of the experiment RESULTS: There were no differences in the arterial blood pressures of the five experimental groups. However, angiotensin II infusion increased the weights of the heart and aortic walls in a dose-dependent manner in the high-salt groups. There was also a dose-dependent increase in proteinuria, N-acetyl-beta-D-glucosaminidase activity (NAG) excretion, and additional glomerular and arterial injuries in the kidney, associated with angiotensin II infusion in the high-salt groups. In the rats given a higher dose of angiotensin II, the high-salt diet significantly increased the weights of the heart and aortic walls and exacerbated the renal function and morphological injuries, compared to the low-salt group. High-salt diet alone increased the kidney and heart weights. However, it did not significantly influence the results of the morphological and functional study. On the other hand, angiotensin II infusion on a low-salt diet showed a trend towards glomerular damage; however, the effects were small and not significant. Similarly, there were few effects of angiotensin II infusion on morphology and functional study on a low-salt diet CONCLUSION: These data clearly show that a high-salt intake increases susceptibility of the kidney to injuries induced by low doses of angiotensin II in normotensive, uni-nephrectomized rats.
The Dahl salt-sensitive (DS) rat, a genetic model of salt-induced hypertension in humans, is more likely to develop severe vascular injuries than a rat with spontaneous hypertension. We designed an experiment to scrutinize the effects of renin-angiotensin inhibition on cognitive dysfunction in the aged, normotensive DS with a passive avoidance test. Eighteen months of treatment with a very low dose of the angiotensin-converting enzyme (ACE) inhibitor cilazapril (2.5 microg/mL in drinking water) or the angiotensin II type 1 receptor antagonist E4177 did not reduce blood pressure throughout the experiment, although in the low dose cilazapril group (12.5 microg/mL in drinking water), blood pressure dropped within 6 months after treatment began. The cilazapril treatments dose-dependently improved memory function in the aged, normotensive DS fed a low-salt diet compared with the untreated, control rats. This improvement was associated with significant increases in hippocampal CA1 cells and capillary densities in the CA1 regions compared with those in the untreated DS. Similarly, E4177 slightly improved the memory dysfunction observed in the aged DS. The cells in the hippocampal CA1 region were restored slightly, but the capillary densities were not influenced by the receptor antagonist. On the other hand, the ACE inhibitor and receptor antagonist both attenuated urinary protein excretions with an improvement of glomerular sclerosis. These data suggest that long-term treatment with an ACE inhibitor improves memory dysfunction probably through restoration of capillary and hippocampal cells. The effects are due to the inhibition of the angiotensin II type 1 receptor and probably to the enhancement of the kallikrein-kinin system.
To investigate the relationships between the activity in potential operated Ca2+ channels (POC), blood pressure, and endothelium in hypertension, we tested the contractile responses to a Ca2+ channel agonist Bay K 8644 (BAY K) in aorta from deoxycorticosterone-acetate-saline (DOCA-S) and reduced renal mass-saline (RRM-S) hypertensive rats. The effects of mechanical rubbing, N omega-Nitro-L-Arginine Methyl Ester (l-NAME) and indomethacin were also examined. Sensitivity to BAY K increased in experimental rats before they became hypertensive and contractile responses were enhanced as hypertension developed. Force development to BAY K was correlated with blood pressure levels. Endothelium removal enhanced the contractile response to BAY K. L-NAME, but not indomethacin, potentiated the response to BAY K. Contractile response to BAY K was negatively correlated with relaxation to acetylcholine. An enhanced contractile response to BAY K was observed also in aged rats. Enhanced activation of vascular POC in hypertension results from elevated blood pressure and partly from diminished inhibitory action of endothelium. Senescence also enhances vascular POC activity.
The time course and clinical significance of hyperkinetic wall motion (HWM) in a noninfarcted area in direct percutaneous transluminal coronary angioplasty (PTCA) has not been clearly demonstrated in patients with acute myocardial infarction (AMI). The objectives of this study were to examine the change in HWM during one-month follow-up after direct PTCA and determine its impact on the recovery of global left ventricular function. A total of 61 patients with first anteroseptal AMI and one vessel disease were evaluated. The paired left ventriculograms in the 30 degrees right anterior oblique view taken both at baseline and follow-up were analyzed by the centerline and area length methods. The severity of hypokinesis was expressed by mean regional wall motion (standard deviation/chord) in most hypocontractile 50% of chords respondable to left anterior descending coronary artery area and HWM by mean regional wall motion in most hypercontractile 50% of chords of noninfarcted area. HWM increased from 0.18 +/- 1.07 to 0.48 +/- 1.30 (p = 0.0608). The delta global ejection fraction (global ejection fraction at follow-up minus global ejection fraction at baseline) was correlated with both delta infarcted wall motion (infarcted wall motion at follow-up minus infarcted wall motion at baseline) and delta HWM (HWM at follow-up minus HWM at baseline) (r = 0.576, p < 0.0001, r= 0.383, p = 0.0036, respectively) during follow-up. Further, the delta global ejection fraction showed better correlation with delta (HWM + infarcted wall motion) [(HWM plus infarcted wall motion at follow-up) minus (HWM plus infarcted wall motion at baseline)] (r= 0.593, p < 0.0001). Direct PTCA resulted in the enhancement of HWVM, which contributed to the increase in the global ejection fraction with the recovery of infarcted wall motion.
To clarify that serum antibody of Helicobacter pylori (H. pylori) and serum pepsinogen I/II ratio are useful or not as a marker of the judgment after eradication therapy, we followed up 84 cases who received eradication therapy comparing with culture and histology (Carnoy's fixation and immunostaining using anti-H. pylori antibody, MIA method). Successful eradication was recognized in 45 of 84 cases (successful group), and remaining 39 cases were unsuccessful (unsuccessful group). Titers of serum H. pylori antibody went down gradually in the successful group, on the other hand, they did not go down constantly and often re-went up in the unsuccessful group. The difference of the various rate of titers in the both groups became clear statistically since 6 months after eradication therapy (p < 0.05). Supposing that cut-off rate of titer was 60% of pre-eradicated titer, sensitivity, specificity, and accuracy were 86.2%, 77.7%, and 84.2%, respectively, at 6 months after eradication therapy. Serum pepsinogen I/II ratio increased regardless of successful or unsuccessful eradication, but the various rate of serum pepsinogen I/II ratio was different in both groups at 1 month and 3 months after eradication therapy (p < 0.05). Serum antibody of H. pylori and serum pepsinogen I/II ratio could be a marker of the judgment after eradication therapy, especially the various rate of serum antibody of H. pylori is useful for the monitor of H. pylori infection in the long term.
Explore the source record for details and available documents.
Annelids are strongly segmented animals that display a high degree of metamerism in their body plan. The embryonic origin of metameric segmentation was examined in an oligochaete annelid Tubifex using lineage tracers. Segmental organization arises sequentially in the anterior-to-posterior direction along the longitudinal axis of the mesodermal germ band, a coherent column of primary blast cells that are produced from the mesodermal teloblast. Shortly after its birth, each primary blast cell undergoes a spatiotemporally stereotyped sequence of cell divisions to generate three classes of cells (in terms of cell size), which together give rise to a distinct cell cluster. Each cluster is composed of descendants of a single primary blast cell; there is no intermingling of cells between adjacent clusters. Relatively small-sized cells in each cluster become localized at its periphery, and they form coelomic walls including an intersegmental septum to establish individuality of segments. A set of cell ablation experiments showed that these features of mesodermal segmentation are not affected by the absence of the overlying ectodermal germ band. These results suggest that each primary blast cell serves as a founder cell of each mesodermal segment and that the boundary between segments is determined autonomously. It is concluded that the metameric body plan of Tubifex arises from an initially simple organization (i.e., a linear series) of segmental founder cells.
We report here a boy suffering from muscle cramps in the right upper extremity. At 32 days of age, he developed purulent meningitis followed by paresis of the right upper extremity. From infancy he had intermittent episodes myoclonus-like involving the right hand. Since he also had true epileptic seizures with loss of consciousness, ocular deviation, and vomiting at 6 and 8 years of age, he was treated with anti-epileptic drugs as therapy for focal motor seizures. At 6 years of age, these episodes increased in frequency. The cramps spread from the right hand to involve the entire upper extremity with pain. At the age of 10, he was referred to Hirosaki University Hospital and was admitted. Using closed circuit television with continuous EEG and EMG monitoring we observed during his episodes repeated EMG abnormalities consisting of continuous discharges of polyphasic motor unit potentials, but no epileptic EEG discharges. We diagnosed these episodes as muscle cramp. His muscle cramps were controlled by medication with muscle relaxants and Chinese medicines. This case illustrates that the differential diagnosis between muscle cramps and epileptic seizures is important for proper treatment.
A dilemma arises in patients with chest pain or other symptoms suggestive of coronary artery disease but without significant coronary artery stenosis or spasm even after the spasm provocation test by either ergonovine or acetylcholine. Incremental doses of intracoronary acetylcholine (up to 100 micrograms for left coronary artery and 50 micrograms for right coronary artery) were administered when intravenous infusion of ergonovine 0.4 mg showed negative results. A total of 39 patients were studied. Provocation test was performed because of chest pain suggestive of coronary artery disease (n = 19), atypical chest pain (n = 6), post balloon angioplasty status (n = 6), silent ischemia (n = 4), Adams-Stokes syndrome (n = 3), and dead-on-arrival (n = 1). Characteristics of chest pain indicated variant angina (n = 11), rest angina (n = 4), and effort angina (n = 4). No electrocardiographic evidence of ischemia was detected before this test in any patient. Spasm was induced in 23 patients (59.0%) with complete obstruction in 7 (30.4%), diffuse vasoconstriction (90-99%) in 14 (60.9%), and focal spasm in 2 (8.7%). The patients with chest pain showed the highest positive rate of 78.9%. Further, the patients with atypical chest pain and miscellaneous reasons also revealed positive rates of 33.3% and 42.9%, respectively. One ventricular tachycardia and 2 atrial fibrillations occurred but terminated spontaneously. This test is useful for detecting spasm in a variety of patients in whom intravenous ergonovine infusion fails to induce spasm.
Here we presented a case of 40-year-old woman who suffered from bilateral facial palsy and headache. She had allegedly had an episode of facial palsy, and facial edema at her age of 14 years. Physical examination revealed swelling of the lips, upward disturbance of the left eye, hypogeusia, the fissured tongue, and bilateral facial palsy. Oral administration of prednisolone 20 mg/day yielded gradual but complete improvement of the facial palsy and hypogeusia within two weeks. Careful analysis of family history disclosed that four members had oro-facio-cervical edema and three had the fissured tongue. A diagnosis of Melkersson-Rosenthal syndrome with possible autosomal dominant inheritance was made based on the clinical findings and familial aggregation of the incomplete form of this syndrome.