ABSTRACT
We previously reported that the sustained component of contraction induced by depolarizing stimulation by high K+ concentration in rat caudal arterial smooth muscle involves a Ca2+-induced Ca2+ sensitization mechanism whereby Ca2+ entry through voltage-gated Ca2+ channels activates proline-rich tyrosine kinase 2 (Pyk2), leading to activation of RhoA/Rho-associated kinase (ROCK). In the present study, we investigated a potential role for Pyk2-mediated RhoA/ROCK activation in contraction mediated by elevation of cytosolic free Ca2+ concentration ([Ca2+]i) induced by a Ca2+ ionophore, ionomycin, rather than by depolarizing stimulation. Ionomycin (60 µM) induced slow and sustained contraction of rat caudal arterial smooth muscle due to influx of Ca2+. Pre-treatment with a myosin light chain kinase (MLCK) inhibitor, ML-9 (30 µM), inhibited both the early phase (4 min) and the sustained phase (30 min) of ionomycin-induced contraction. On the other hand, a ROCK inhibitor, HA-1077 (3 µM), and Pyk2 inhibitors, sodium salicylate (10 mM) and PF-431396 (3 µM), suppressed only the sustained phase of ionomycin-induced contraction. A calmodulin (CaM) inhibitor, W-7 (150 µM), but not W-5 (150 µM), suppressed the early phase of contraction. Early or sustained increase of ionomycin-induced 20 kDa light chain of myosin (LC20) phosphorylation was inhibited by each inhibitor in a manner similar to the attenuation of contraction. These results indicate that the early phase of ionomycin-induced contraction is mediated by MLCK activation by [Ca2+]i elevation, whereas the sustained phase of ionomycin-induced contraction involves RhoA/ROCK activation and inhibition of myosin light chain phosphatase (MLCP) through CaM-independent Pyk2 activation by [Ca2+]i elevation.
Subject(s)
Calcium , Ionomycin , Muscle Contraction , rho-Associated Kinases , Animals , Ionomycin/pharmacology , Male , Muscle Contraction/drug effects , Calcium/metabolism , rho-Associated Kinases/metabolism , rho-Associated Kinases/antagonists & inhibitors , Myosin-Light-Chain Kinase/metabolism , Myosin-Light-Chain Kinase/antagonists & inhibitors , Rats , Muscle, Smooth, Vascular/drug effects , Muscle, Smooth, Vascular/physiology , Muscle, Smooth, Vascular/metabolism , Focal Adhesion Kinase 2/metabolism , Calcium Ionophores/pharmacology , rhoA GTP-Binding Protein/metabolism , Rats, Sprague-Dawley , Rats, Wistar , Calmodulin/metabolismABSTRACT
OBJECTIVE: At our institution, patients with hematological disease who require Pneumocystis jirovecii pneumonia (PJP) prophylaxis were administered atovaquone at a low dose (750 mg/day). However, there have been few reports on the efficacy of low-dose atovaquone administration, and the purpose of this study is, therefore, to investigate its effectiveness. MATERIALS AND METHODS: We investigated the expression of PJP in patients with hematological disease who received atovaquone administration. Atovaquone was administered at a low dose of 750 mg once daily, and the follow-up time was the period of PJP prophylaxis that included atovaquone administration. RESULTS: 85 patients were included in the study. The median age of the study population was 72 years (range: 33 - 97). The duration of atovaquone treatment and follow-up time were 150 days (22 - 1,018) and 258 days (22 - 1,457), respectively. In hematologic diseases, multiple myeloma was high in 31 patients and malignant lymphoma in 28 patients. No patients exhibited PJP during the observation period. CONCLUSION: In hematological disease patients with relatively low risk of PJP, low-dose atovaquone may prevent the onset of PJP.
Subject(s)
Hematologic Diseases , Pneumocystis carinii , Pneumonia, Pneumocystis , Humans , Adult , Middle Aged , Aged , Aged, 80 and over , Pneumonia, Pneumocystis/prevention & control , Pneumonia, Pneumocystis/drug therapy , Pneumonia, Pneumocystis/epidemiology , Atovaquone/adverse effects , Trimethoprim, Sulfamethoxazole Drug Combination , Hematologic Diseases/complications , Hematologic Diseases/drug therapy , Retrospective StudiesABSTRACT
WHAT IS KNOWN AND OBJECTIVE: It was previously reported that the incidence of lenalidomide (LEN)-induced skin rash is reduced by administration of bortezomib (BOR) prior to LEN administration in patients with multiple myeloma (MM). Therefore, we investigated whether LEN-induced skin rash is affected by the duration of BOR administration and the dosing interval between BOR and LEN administration. METHOD: A retrospective investigation was conducted among MM patients who received BOR treatment prior to LEN treatment in Eiju General Hospital from May 2010 to December 2020. We investigated whether the BOR administration duration and interval duration from the completion of BOR administration to the initial LEN administration affect the development of LEN-induced skin rash. RESULT AND DISCUSSION: Twenty-eight of the 81 patients exhibited LEN-induced skin rash (34.6%). The administered duration, but not the interval, was significantly longer in the group without skin rash. Cut-off values were set for the duration of administration and interval, which were 35 days and 30 days, respectively. Multivariate analysis was performed on patients which are administered duration of more than 35 days and intervals of less than 30 days, and those who are not applicable. A significant difference was observed in the incidence of skin rash for each factor. WHAT IS NEW AND CONCLUSION: The risk of reduced LEN-induced skin rash is affected not only by the presence of prior BOR administration, but also by the duration of BOR and the interval from the completion of BOR to the initial LEN administration.
Subject(s)
Exanthema , Multiple Myeloma , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Bortezomib/adverse effects , Dexamethasone/therapeutic use , Exanthema/chemically induced , Exanthema/epidemiology , Exanthema/prevention & control , Humans , Lenalidomide/adverse effects , Multiple Myeloma/drug therapy , Retrospective StudiesABSTRACT
WHAT IS KNOWN AND OBJECTIVE: Skin rash is one of the typical side effects of lenalidomide (LEN) treatment. Desensitization therapies have been reported to be effective in patients with severe skin rash caused by LEN. However, they have proved impractical due to the complexity of the protocols. CASE SUMMARIES: We present 5 patients who developed severe LEN-induced skin rash. The five patients received our simple, slow desensitization protocol, and all were re-administered LEN with no adverse reaction. WHAT IS NEW AND CONCLUSION: Our simpler and slow desensitization protocol, which desensitizes the patients without reducing the effect of LEN, includes drug holidays, similar to the usual LEN dosing schedule, and moreover is recommended as a treatment option especially for elderly patients with no housemate to help with medical management.
Subject(s)
Exanthema/chemically induced , Exanthema/therapy , Lenalidomide/therapeutic use , Multiple Myeloma/drug therapy , Aged , Dose-Response Relationship, Drug , Drug Administration Schedule , Female , Humans , Lenalidomide/administration & dosage , Lenalidomide/adverse effects , Male , Middle Aged , Patient AcuityABSTRACT
The aim of the present study was to identify the risk factors for lenalidomide (Len)-associated skin rash. We retrospectively investigated the medical records of 144 multiple myeloma patients treated with Len-containing therapies. A total of 64 of 144 patients included in the study had skin rash (44.4%). 50 patients developed skin rash within 4 weeks of starting Len treatment. Further, in 29 patients, the skin rash appeared at an early stage (within 1 week) after treatment initiation. Univariate analysis revealed that the risk of skin rash significantly increased in patients with advanced age (p = 0.017), myeloma subtype (p = 0.014), no prior chemotherapy (p = 0.012), and Len dosage (p = 0.008). Multivariate logistic regression analysis demonstrated that advanced age (≥ 70 years), BJP-subtype of myeloma and no prior chemotherapy were significant risk factors for the skin rash associated with Len. Thus, patients with these risk factors should be carefully monitored for the appearance of skin rash during the treatment with Len.
Subject(s)
Exanthema , Multiple Myeloma , Aged , Antineoplastic Combined Chemotherapy Protocols , Dexamethasone/therapeutic use , Exanthema/chemically induced , Exanthema/diagnosis , Exanthema/epidemiology , Humans , Lenalidomide/adverse effects , Multiple Myeloma/drug therapy , Retrospective Studies , Risk FactorsABSTRACT
Phenytoin, a voltage-gated sodium channel (NaV channel) antagonist, reportedly inhibits arginine vasopressin (AVP) release from an isolated rat neurohypophysis. So far, it is uncertain whether phenytoin has a direct action on ectopic AVP-producing neuroendocrine tumors. We studied the effect of phenytoin on the release of copeptin, the C-terminal fragment of pro-AVP, and expression of AVP gene in the human small cell lung cancer cell line Lu-165. Cells were maintained in RPMI1640 medium with 10% fetal bovine serum and were used within the fifth passage. Copeptin was detected using a new sandwich immunoassay, and AVP mRNA levels were measured using real-time reverse transcription polymerase chain reaction. Treatment with phenytoin at a concentration of 25 µg/mL, but not at 5 or 10 µg/mL, had an inhibitory effect on copeptin levels in the medium at 48 h. At the same concentration, AVP mRNA levels in Lu-165 cells also decreased. Although a sodium challenge with added sodium at 20 mEq/L increased copeptin levels in the medium, a sodium challenge with added sodium at 10 and 20 mEq/L had no effect on AVP mRNA levels. Phenytoin at a concentration of 25 µg/mL suppressed copeptin levels in the medium under the sodium challenge with added sodium at 10 and 20 mEq/L. Phenytoin at a concentration of 25 µg/mL also decreased AVP mRNA levels in Lu-165 cells under the sodium challenge with added sodium at 10 mEq/L, but not at 20 mEq/L. Among five tested NaV channel subunits, NaV1.3 was highly expressed in Lu-165 cells. However, phenytoin significantly decreased NaV1.3 mRNA levels under the sodium challenge with added sodium at 10 and 20 mEq/L. These results suggest that Lu-165 cells are sensitive to phenytoin and sodium to control of AVP release and its gene expression. Phenytoin might have a direct action on ectopic AVP-producing tumors, suggesting the importance of NaV channels in AVP-producing neuroendocrine tumors.
ABSTRACT
Elevated levels of arginine vasopressin (AVP) have been reported to be involved in the pathogenesis of heart failure (HF). Recent evidence has shown the role of copeptin, the C-terminal fragment of pro-AVP, as a biomarker in patients with HF. However, the relevant information is still limited. Therefore, we evaluated 39 Japanese patients admitted for HF between 2013 and 2015 (23 males and 16 females with an average age of 79.2 years). They were treated according to the Japanese acute HF guideline. Plasma copeptin levels were measured on admission and about 1 week later. The median plasma copeptin levels on admission were 0.5 (0.1-50.6) pmol/L, higher than the normal values (0.24 ± 0.06 pmol/L). Despite the similar clinical severity on admission, the patients showed great variability in plasma copeptin levels. They were divided into three groups (13 patients/group) according to plasma copeptin levels on admission: highest (> 30.8 pmol/L), midrange, and lowest (< 0.2 pmol/L) groups. Initial treatment improved HF symptoms in 37 of 39 patients, with the two unresponsive patients in the lowest group. Notably, plasma copeptin responses to initial treatment were different, depending on admission copeptin levels. The initial treatment significantly decreased copeptin levels in the highest group, but increased copeptin levels in the lowest group. By contrast, patients in the midrange group showed no significant changes. Thus, the treatment appears to restore the plasma copeptin levels. In conclusion, HF is a complex syndrome with the differential integration of stimulatory and inhibitory inputs to the AVP/copeptin secretory system.
Subject(s)
Glycopeptides/blood , Heart Failure/blood , Aged , Female , Heart Failure/physiopathology , Heart Function Tests , Humans , Male , Middle Aged , Multivariate Analysis , Natriuretic Peptide, Brain/blood , Osmolar Concentration , Peptide Fragments/blood , Prospective Studies , Sodium/blood , Treatment OutcomeABSTRACT
Depolarization of the plasma membrane is a key mechanism of activation of contraction of vascular smooth muscle. This is commonly achieved in isolated, de-endothelialized vascular smooth muscle strips by increasing extracellular [K(+)] (replacing Na(+) by K(+)) and leads to a rapid phasic contraction followed by a sustained tonic contraction. The initial phasic contractile response is due to opening of voltage-gated Ca(2+) channels and entry of extracellular Ca(2+), which binds to calmodulin, leading to activation of myosin light chain kinase, phosphorylation of the regulatory light chains of myosin II at Ser19 and cross-bridge cycling. The subsequent tonic contractile response involves, in addition to myosin light chain kinase activation, Ca(2+)-induced Ca(2+) sensitization whereby Ca(2+) entry activates the RhoA/Rho-associated kinase pathway leading to phosphorylation of MYPT1 (the myosin targeting subunit of myosin light chain phosphatase) and inhibition of the phosphatase. Investigations into the mechanism of activation of RhoA by Ca(2+) have implicated a genistein-sensitive tyrosine kinase, and recent evidence indicates this to be the Ca(2+)-dependent tyrosine kinase, Pyk2.
Subject(s)
Calcium/metabolism , Focal Adhesion Kinase 2/metabolism , Membrane Potentials/physiology , Muscle Contraction/physiology , Muscle, Smooth, Vascular/metabolism , Muscle, Smooth, Vascular/physiology , Animals , Myosin Light Chains/metabolism , rho-Associated Kinases/metabolismABSTRACT
Depolarization of the vascular smooth muscle cell membrane evokes a rapid (phasic) contractile response followed by a sustained (tonic) contraction. We showed previously that the sustained contraction involves genistein-sensitive tyrosine phosphorylation upstream of the RhoA/Rho-associated kinase (ROK) pathway leading to phosphorylation of MYPT1 (the myosin-targeting subunit of myosin light chain phosphatase (MLCP)) and myosin regulatory light chains (LC20). In this study, we addressed the hypothesis that membrane depolarization elicits activation of the Ca(2+)-dependent tyrosine kinase Pyk2 (proline-rich tyrosine kinase 2). Pyk2 was identified as the major tyrosine-phosphorylated protein in response to membrane depolarization. The tonic phase of K(+)-induced contraction was inhibited by the Pyk2 inhibitor sodium salicylate, which abolished the sustained elevation of LC20 phosphorylation. Membrane depolarization induced autophosphorylation (activation) of Pyk2 with a time course that correlated with the sustained contractile response. The Pyk2/focal adhesion kinase (FAK) inhibitor PF-431396 inhibited both phasic and tonic components of the contractile response to K(+), Pyk2 autophosphorylation, and LC20 phosphorylation but had no effect on the calyculin A (MLCP inhibitor)-induced contraction. Ionomycin, in the presence of extracellular Ca(2+), elicited a slow, sustained contraction and Pyk2 autophosphorylation, which were blocked by pre-treatment with PF-431396. Furthermore, the Ca(2+) channel blocker nifedipine inhibited peak and sustained K(+)-induced force and Pyk2 autophosphorylation. Inhibition of Pyk2 abolished the K(+)-induced translocation of RhoA to the particulate fraction and the phosphorylation of MYPT1 at Thr-697 and Thr-855. We conclude that depolarization-induced entry of Ca(2+) activates Pyk2 upstream of the RhoA/ROK pathway, leading to MYPT1 phosphorylation and MLCP inhibition. The resulting sustained elevation of LC20 phosphorylation then accounts for the tonic contractile response to membrane depolarization.
Subject(s)
Focal Adhesion Kinase 2/metabolism , Muscle, Smooth, Vascular/physiology , Animals , Electrophoresis, Polyacrylamide Gel , Male , Muscle Contraction/physiology , Muscle, Smooth, Vascular/enzymology , Phosphorylation , Rats , Rats, WistarSubject(s)
Arteries/drug effects , Genistein/pharmacology , Membrane Potentials/physiology , Muscle Contraction/drug effects , Muscle, Smooth, Vascular/drug effects , Protein Kinase Inhibitors/pharmacology , Protein-Tyrosine Kinases/metabolism , Tyrosine/metabolism , rho-Associated Kinases/physiology , Amides/pharmacology , Animals , Calcium/metabolism , Calcium/physiology , In Vitro Techniques , Male , Myosin-Light-Chain Phosphatase/metabolism , Phosphorylation/drug effects , Potassium/physiology , Protein Phosphatase 1/metabolism , Protein Tyrosine Phosphatases/antagonists & inhibitors , Protein-Tyrosine Kinases/antagonists & inhibitors , Pyridines/pharmacology , Rats , Rats, Sprague-Dawley , Vanadates/pharmacology , rho-Associated Kinases/antagonists & inhibitors , rho-Associated Kinases/metabolismABSTRACT
The Goto-Kakizaki (GK) rat is a non-obese and spontaneous model of mild Type 2 diabetes mellitus. In the present study, we compared the regulatory mechanisms of endogenous norepinephrine (NE) release from sympathetic nerves of caudal arteries of 12-week-old GK rats and age-matched normal Wistar rats. Electrical stimulation (ES) evoked significant NE release from caudal arteries of Wistar and GK rats. The amounts of NE released by ES were almost equal in Wistar and GK rats, although the NE content in caudal artery of GK rats was significantly lower than that of Wistar rats. We examined the effects of an α2-adrenoceptor agonist, clonidine (CLO), and an α2-adrenoceptor antagonist, yohimbine (YOH), on the release of endogenous NE evoked by ES. CLO significantly reduced NE release from caudal arteries of Wistar but not GK rats. On the other hand, YOH significantly increased NE release from both rats. Furthermore, we examined the effects of an A1-adenosine receptor agonist, 2-chloroadenosine (2CA), and an A1-adenosine receptor antagonist, 8-sulfophenyltheophylline (8SPT), on the release of endogenous NE evoked by ES. 2CA significantly reduced NE release from caudal arteries of Wistar but not GK rats. On the other hand, 8SPT did not affect NE release from both rats. These results suggest that the dysfunction of negative feedback regulation of NE release via presynaptic receptors on sympathetic nerves in GK rats may be involved in the autonomic nervous system dysfunction associated with diabetic autonomic neuropathy.
Subject(s)
Adrenergic Neurons/physiology , Arteries/innervation , Diabetes Mellitus, Type 2/physiopathology , Norepinephrine/physiology , Sympathetic Nervous System/physiopathology , Adrenergic alpha-2 Receptor Agonists/pharmacology , Adrenergic alpha-2 Receptor Antagonists/pharmacology , Animals , Arteries/physiopathology , Clonidine/pharmacology , Electric Stimulation , In Vitro Techniques , Rats , Rats, Wistar , Receptor, Adenosine A1/physiology , Receptors, Adenosine A2/physiology , Yohimbine/pharmacologyABSTRACT
Nicorandil significantly reducted the incidence of major coronary events in patients with stable angina in a long-term trial, although there are few reports on its short-term efficacy in the treatment and prevention of angina symptoms. We performed a meta-analysis of the short-term efficacy of nicorandil compared with antianginal drugs for stable angina. We selected 20 reports (vs. ß-blockers, n=6; vs. nitrates, n=6; vs. calcium antagonists, n=8) of prospective controlled trials from MEDLINE, the Cochrane Library, and Japana Centra Revuo Medicina. The trials were short in duration (median 5 weeks). We combined the results using odds ratios (OR) for discrete data and weighted mean differences (WMD) for continuous data. Compared with antianginal drugs, nicorandil did not show significant reduction of angina episodes per week (vs. ß-blockers, -1.50 [95% confidence interval (CI): -4.09, 1.09]; vs. nitrates, 0.22 [95% CI: -1.22, 1.65]; vs. calcium antagonists, -0.23 [95% CI: -1.37, 0.90]). Furthermore, there were no significant differences in time to ischemia (total exercise duration, time to 1-mm ST depression, time to onset of pain). Although the total numbers of adverse events with each antianginal drug were similar, heart rate and blood pressure were significantly decreased by calcium antagonists but not changed by nicorandil (8.09 [95% CI: 3.20, 12.98] and 8.64 [95% CI: 3.28, 13.99], respectively). Thus this study suggests that short-term therapy with nicorandil is as effective as standard therapy and that nicorandil can also be used as a first-line agent in patients with stable angina.
Subject(s)
Adrenergic beta-Antagonists/therapeutic use , Angina Pectoris/drug therapy , Calcium Channel Blockers/therapeutic use , Nicorandil/therapeutic use , Nitrates/therapeutic use , Adrenergic beta-Antagonists/adverse effects , Angina Pectoris/physiopathology , Angina Pectoris/prevention & control , Blood Pressure , Calcium Channel Blockers/adverse effects , Controlled Clinical Trials as Topic , Endpoint Determination , Heart Rate , Humans , Nicorandil/adverse effects , Nitrates/adverse effects , Odds Ratio , Prospective StudiesABSTRACT
1. Previously, we found that Ca(2+) entry from the extracellular space via alpha(1)-adrenoceptor-activated, Ca(2+)-permeable channels, but not voltage-gated Ca(2+) channels, is impaired in endothelium-denuded caudal artery smooth muscle from Type 2 diabetic Goto-Kakizaki (GK) rats. In the present study, we investigated the impairment of Ca(2+) entry mechanisms via Ca(2+)-permeable channels from the extracellular space in response to alpha(1)-adrenoceptor stimulation (cirazoline) in endothelium-denuded caudal artery strips isolated from GK rats. 2. The contraction of caudal artery strips from GK rats in response to the sarcoplasmic reticulum Ca(2+)-ATPase inhibitor cyclopiazonic acid (10 micromol/L), which causes depletion of Ca(2+) stores and subsequent store-operated Ca(2+) (SOC) entry, was significantly depressed compared with that of Wistar rats (maximal force 0.023 +/- 0.004 vs 0.058 +/- 0.005 mN/mg tissue wet weight, respectively). These results suggest that receptor-activated Ca(2+) entry through SOC channels is impaired in caudal artery smooth muscle in GK rats. 3. The classic transient receptor potential (TRPC) channels, which constitute SOC and receptor-operated cation channels, play an important role in Ca(2+) regulation. Therefore, we investigated the mRNA and protein expression of TRPC channels in caudal artery smooth muscle from Wistar and GK rats using reverse transcription-polymerase chain reaction and immunoblotting. 4. Expression of TRPC1, TRPC3 and TRPC6 mRNA and protein was found in Wistar rats. However, in GK rats, in addition to the expression of these TRPC channels, mRNA and protein expression of TRPC4 was found. The expression of TRPC1 and TRPC6, but not TRPC3, was increased approximately twofold in GK rats compared with Wistar rats. 5. These results suggest that changes in TRPC channel expression may be responsible, in part, for the dysfunction of receptor-mediated Ca(2+) entry in caudal artery smooth muscle of GK rats.
Subject(s)
Calcium/metabolism , Diabetes Mellitus, Type 2/metabolism , Muscle, Smooth, Vascular/metabolism , TRPC Cation Channels/metabolism , Adrenergic alpha-Agonists/pharmacology , Animals , Arteries/metabolism , Calcium/analysis , Enzyme Inhibitors/pharmacology , Imidazoles/pharmacology , Indoles/pharmacology , Male , Muscle, Smooth, Vascular/drug effects , Rats , Rats, Wistar , Sarcoplasmic Reticulum Calcium-Transporting ATPases/antagonists & inhibitors , Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism , TRPC Cation Channels/analysis , TRPC Cation Channels/drug effectsABSTRACT
We examined the effects of chondroitinases on the release of dermatan sulfate (DS)-induced arginine amidase (AA) from rabbit ear artery. DS-induced AA release was significantly decreased by treatment with chondroitinase ABC (ABCase) in the rabbit ear artery. On the other hand, Chondroitinase ACII (ACIIase) enhanced spontaneous and DS-induced AA release. Heat-inactivated ABCase and ACIIase did not affect spontaneous and DS-induced AA release. Furthermore, ABCase, but not ACIIase and heat-inactivated chondroitinases, degraded DS. These results indicate that the facilitatory effect of DS-induced AA release from the rabbit ear artery is affected by the molecular size of DS.
Subject(s)
Anticoagulants/pharmacology , Arteries/drug effects , Chondroitin Lyases/pharmacology , Dermatan Sulfate/metabolism , Serine Endopeptidases/metabolism , Animals , Arteries/metabolism , Chondroitin ABC Lyase/pharmacology , Dermatan Sulfate/chemistry , Ear , Rabbits , Structure-Activity RelationshipABSTRACT
1. In the present study, we compared the responsiveness of de-endothelialized caudal artery smooth muscle strips, isolated from Type 2 diabetic Goto-Kakizaki (GK) and normal Wistar rats, to alpha(1)-adrenoceptor stimulation (cirazoline) and membrane depolarization (K(+)). 2. The contractile and myosin 20 kDa light chain (LC(20)) phosphorylation responses to 0.3 micromol/L cirazoline of caudal artery strips isolated from 12-week-old GK rats were significantly reduced compared with those of age-matched Wistar rats, whereas the contractile and LC(20) phosphorylation responses to 60 mmol/L K(+) were unaltered. 3. Stimulation of fura 2-AM-loaded strips from GK rats with 0.3 micromol/L cirazoline induced a significantly smaller rise in [Ca(2+)](i) (by approximately 20%) compared with that in strips from Wistar rats, whereas comparable Ca(2+) transients were evoked by K(+) in both. 4. Using quantitative polymerase chain reaction, no significant differences were detected in the mRNA expression of alpha(1A)-, alpha(1B)- and alpha(1D)-adrenoceptor subtypes between GK and Wistar rats. 5. Cirazoline (1 micromol/L)- and caffeine (20 mmol/L)-induced contractions in the absence of extracellular Ca(2+) were unaltered in GK rats, suggesting that the release of Ca(2+) from the sarcoplasmic reticulum in response to cirazoline does not differ between GK and Wistar rats. 6. The results of the present study suggest that Ca(2+) entry from the extracellular space via alpha(1)-adrenoceptor-activated, Ca(2+)-permeable channels, but not via membrane depolarization and voltage-gated L-type Ca(2+) channels, is impaired in caudal artery smooth muscle of GK rats.
Subject(s)
Adrenergic alpha-1 Receptor Agonists/pharmacology , Arteries/physiopathology , Diabetes Mellitus, Type 2/physiopathology , Muscle, Smooth, Vascular/physiopathology , Receptors, Adrenergic, alpha-1/physiology , Vasoconstriction/physiology , Animals , Arteries/drug effects , Imidazoles/pharmacology , In Vitro Techniques , Male , Muscle, Smooth, Vascular/drug effects , Rats , Rats, Wistar , Vasoconstriction/drug effectsABSTRACT
A recent clinical study has shown that carvedilol has a significantly more favorable effect than metoprolol on survival rate in patients with heart failure. This may be due to actions of carvedilol such as beta(2)-adrenoceptor blockade, alpha-adrenergic receptor blockade and other properties such as anti-oxidant effects that are not yet fully understood. We compared the effects of racemic carvedilol, metoprolol and carvedilol enantiomers on cardiac hypertrophy at similar heart rate in rats with isoproterenol-induced cardiac hypertrophy. Continuous administration of isoproterenol for 2 weeks produced heart failure, which is characterized by an increased heart rate, cardiac hypertrophy and downregulation of beta-adrenoceptors. The doses of racemic carvedilol and metoprolol were adjusted to obtain a similar heart rate in rats with isoproterenol-induced cardiac hypertrophy. The reduction of left ventricular weight and improvement of cAMP production induced by carvedilol were superior to those induced by metoprolol. Although heart rate, blood pressure and cAMP production were not affected by R-carvedilol, left ventricular weight was significantly reduced as a result of alpha-adrenoceptor blockade. The improvement of cAMP production by S-carvedilol was significantly higher than that induced by coadministration of R-carvedilol and metoprolol, suggesting that beta(2)-adrenoceptor blockade partly contributed to the improvement of signal transduction in rats with isoproterenol-induced cardiac hypertrophy. This study has demonstrated that the effects of carvedilol on cAMP production and cardiac hypertrophy in rats with isoproterenol-induced cardiac hypertrophy are superior to those induced by metoprolol at a similar heart rate.
Subject(s)
Adrenergic alpha-Antagonists/pharmacology , Adrenergic beta-Antagonists/pharmacology , Carbazoles/pharmacology , Cardiomegaly/drug therapy , Heart Failure/drug therapy , Metoprolol/pharmacology , Propanolamines/pharmacology , Adenylyl Cyclases/metabolism , Animals , Blood Pressure/drug effects , Cardiomegaly/chemically induced , Cardiomegaly/metabolism , Cardiomegaly/physiopathology , Carvedilol , Cyclic AMP/metabolism , Disease Models, Animal , Heart Failure/etiology , Heart Failure/metabolism , Heart Failure/physiopathology , Heart Rate/drug effects , Isoproterenol , Male , Myocardium/enzymology , Rats , Rats, Wistar , Receptors, Adrenergic, beta/metabolism , Time Factors , Ventricular Function, Left/drug effectsABSTRACT
No previous reports have compared clarithromycin (CAM), rifampicin (RFP) and ethambutol (EB) containing regimens with and without an aminoglycoside antibiotic kanamycin (KM) for the treatment of pulmonary Mycobacterium avium complex (MAC) disease. We conducted a retrospective study to investigate the clinical efficacy of KM using data from 40 patients who received combined chemotherapy for MAC disease with or without KM in the National Hospital Organization Tokyo Hospital from July, 1999 to December, 2005. All patients were administered CAM, RFP and EB for 6 to 12 months, and 20 of the 40 simultaneously received combined chemotherapy with KM. The difference in the backgrounds of the groups was not statistically significant. The improvement rates of clinical symptoms and radiological findings were significantly higher in the KM-treated group than in the KM-untreated group (75% versus 35% and 80% versus 25%). Moreover, the sputum relapse rate was significantly lower in the KM-treated group (18% versus 75%). However, there were no significant differences in the sputum conversion rate (55% with KM versus 40% without KM). As for adverse reactions, there were no significant differences between the groups. Furthermore, we examined time-kill kinetics of KM and streptomycin (SM) against a clinical isolate of M. avium. Most M. avium was killed by KM and SM at concentrations higher than MIC (8 microg/ml), and concentration- and time-dependent killing by KM and SM were almost identical. These observations indicate that KM is effective for treatment of patients with MAC disease.
Subject(s)
Anti-Bacterial Agents/therapeutic use , Kanamycin/therapeutic use , Mycobacterium avium-intracellulare Infection/drug therapy , Aged , Antitubercular Agents/therapeutic use , Clarithromycin/therapeutic use , Drug Therapy, Combination , Ethambutol/therapeutic use , Female , Humans , Male , Middle Aged , Retrospective Studies , Rifampin/therapeutic useABSTRACT
1. We have reported previously that isolated single smooth muscle cells from guinea-pig taenia caecum respond to acetylcholine (ACh) in an all-or-none manner. 2. To clarify the roles of intracellular Ca(2+) stores in the all-or-none response of isolated smooth muscle cells from guinea-pig taenia caecum to ACh, we examined the inositol 1,4,5-trisphosphate (IP(3))-induced contractile response in Staphylococcus aureus alpha-toxin-permeabilized smooth muscle cells and the effect of depletion of intracellular Ca(2+) stores on the all-or-none response to ACh in intact smooth muscle cells. 3. alpha-Toxin-permeabilized smooth muscle cells responded to 3-30 nmol/L or 0.3-3 nmol/L IP(3) in the presence of 0.2 micromol/L Ca(2+) with 1 mmol/L EGTA or 0.1 mmol/L EGTA, respectively, in an all-or-none manner. These results suggest that Ca(2+) release induced by IP(3) is Ca(2+) dependent and is evoked in an all-or-none manner. 4. In the presence of the Ca(2+) ionophore A23187 (0.1 micromol/L) or the sarcoplasmic reticulum Ca(2+)-ATPase inhibitor cyclopiazonic acid (1 micromol/L), the shortening of intact smooth muscle cells induced by increasing concentrations of ACh showed a graded response, but not an all-or-none response. 5. In conclusion, the results suggest that Ca(2+) release from Ca(2+) stores induced by IP(3) plays an important role in the all-or-none response of intact smooth muscle cells to ACh.
Subject(s)
Acetylcholine/pharmacology , Calcium/metabolism , Cecum/drug effects , Muscle Contraction/drug effects , Muscle, Smooth/drug effects , Myocytes, Smooth Muscle/drug effects , Animals , Cecum/cytology , Cecum/metabolism , Cholinergic Agents/pharmacology , Guinea Pigs , Male , Muscle Contraction/physiology , Muscle, Smooth/cytology , Muscle, Smooth/metabolism , Myocytes, Smooth Muscle/physiology , PermeabilityABSTRACT
Evidence has recently been accumulating that a sirolimus-eluting stent (DES) is superior to a bare-metal stent (BMS) in preventing restenosis after percutaneous coronary intervention (PCI), and an increasing number of Japanese hospitals have been adopting DES. We conducted a retrospective study to identify clinical factors that influence the risk of restenosis after PCI, including stent types, by analyzing the data of 49 continuous patients who received PCI and follow-up coronary angiography in Hiratsuka City Hospital between March, 2004 and March, 2005. Age, sex, body mass index, smoking, complications, clinical diagnosis before PCI, the site and number of stenoses, implanted stent type (BMS or DES), the number of stents used, maximum inflating pressure and withdrawal of ticlopidine due to its adverse drug reactions were chosen as potential factors that may influence the risk of restenosis, and the correlation between these factors and restenosis was tested by Student's t-test or chi-square test. Coronary restenosis developed in 10 out of 49 patients, and factors having significant correlation with restenosis were age (73+/-7 in the restenosis group (R) and 64+/-12 in the non-restenosis group (N) (p<0.05)) and the type of stent (DES used in only one of 10 cases in R whereas in 24 of 39 in N (p<0.001)). Multivariate analysis showed older age (odds ratio (OR): 1.200 (95% CI: 1.038-2.823)) and the use of DES are independent predictors for restenosis (OR: 0.015 (95%CI: 0.001-0.249)). Our study further supports the efficacy of DES in PCI, but its long-term outcome is yet to be confirmed.
Subject(s)
Angioplasty, Balloon, Coronary , Coronary Restenosis/etiology , Stents , Adult , Age Factors , Aged , Aged, 80 and over , Angioplasty, Balloon, Coronary/adverse effects , Female , Humans , Male , Middle Aged , Retrospective Studies , Risk Factors , Stents/adverse effects , Ticlopidine/administration & dosage , Ticlopidine/adverse effectsABSTRACT
Lampreys are one of the most primitive vertebrates diverged some 500 million years ago. It has long been known that parasitic lampreys secrete anticoagulant from their buccal glands and prevent blood coagulation of host fishes. We found two major protein components of 160 and 26 kDa in the buccal gland secretion of parasitic river lamprey, Lethenteron japonicum. The larger protein was identified as river lamprey plasma albumin. The complete primary structure of the 26-kDa protein was determined by protein and cDNA analysis. It belonged to the cysteine-rich secretory protein (CRISP) superfamily that includes recently identified reptile venom ion-channel blockers. Lamprey CRISP blocked depolarization-induced contraction of rat-tail arterial smooth muscle, but showed no effect on caffeine-induced contraction. The result suggests that lamprey CRISP is an L-type Ca(2+)-channel blocker and may act as a vasodilator, which facilitates the parasite to feed on the host's blood. The lamprey CRISP protein contains a number of short insertions throughout the sequence, when aligned with reptilian venom CRISP proteins, probably due to the large evolutionary distance between the Agnatha and the Reptilia, and may represent a novel class of venom CRISP family proteins.