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1.
Bone Joint J ; 95-B(3): 411-8, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23450030

ABSTRACT

The aim of this study was to determine whether the level of circulating C-reactive protein (CRP) before treatment predicted overall disease-specific survival and local tumour control in patients with a sarcoma of bone. We retrospectively reviewed 318 patients who presented with a primary sarcoma of bone between 2003 and 2010. Those who presented with metastases and/or local recurrence were excluded. Elevated CRP levels were seen in 84 patients before treatment; these patients had a poorer disease-specific survival (57% at five years) than patients with a normal CRP (79% at five years) (p < 0.0001). They were also less likely to be free of recurrence (71% at five years) than patients with a normal CRP (79% at five years) (p = 0.04). Multivariate analysis showed the pre-operative CRP level to be an independent predictor of survival and local control. Patients with a Ewing's sarcoma or chondrosarcoma who had an elevated CRP before their treatment started had a significantly poorer disease-specific survival than patients with a normal CRP (p = 0.02 and p < 0.0001, respectively). Patients with a conventional osteosarcoma and a raised CRP were at an increased risk of poorer local control. We recommend that CRP levels are measured routinely in patients with a suspected sarcoma of bone as a further prognostic indicator of survival.


Subject(s)
Biomarkers, Tumor/blood , Bone Neoplasms/mortality , C-Reactive Protein/metabolism , Sarcoma/mortality , Adolescent , Adult , Aged , Aged, 80 and over , Bone Neoplasms/blood , Bone Neoplasms/therapy , Child , Child, Preschool , Combined Modality Therapy , Female , Follow-Up Studies , Humans , Male , Middle Aged , Multivariate Analysis , Neoplasm Recurrence, Local/blood , Neoplasm Recurrence, Local/epidemiology , Prognosis , Retrospective Studies , Sarcoma/blood , Sarcoma/therapy , Survival Analysis , Young Adult
2.
J Bone Joint Surg Br ; 93(12): 1665-9, 2011 Dec.
Article in English | MEDLINE | ID: mdl-22161931

ABSTRACT

We retrospectively compared the outcome after the treatment of giant cell tumours of bone either with curettage alone or with adjuvant cementation. Between 1975 and 2008, 330 patients with a giant cell tumour were treated primarily by intralesional curettage, with 84 (25%) receiving adjuvant bone cement in the cavity. The local recurrence rate for curettage alone was 29.7% (73 of 246) compared with 14.3% (12 of 84) for curettage and cementation (p = 0.001). On multivariate analysis both the stage of disease and use of cement were independent significant factors associated with local recurrence. The use of cement was associated with a higher risk of the subsequent need for joint replacement. In patients without local recurrence, 18.1% (13 of 72) of those with cement needed a subsequent joint replacement compared to 2.3% (4 of 173) of those without cement (p = 0.001). In patients who developed local recurrence, 75.0% (9 of 12) of those with previous cementation required a joint replacement, compared with 45.2% (33 of 73) of those without cement (p = 0.044).


Subject(s)
Bone Cements/therapeutic use , Bone Neoplasms/surgery , Curettage , Giant Cell Tumor of Bone/surgery , Orthopedic Procedures/methods , Adolescent , Adult , Aged , Bone Neoplasms/pathology , Female , Femoral Neoplasms/surgery , Follow-Up Studies , Giant Cell Tumor of Bone/pathology , Humans , Humerus/surgery , Male , Middle Aged , Neoplasm Recurrence, Local , Radius/surgery , Retrospective Studies , Tibia/surgery , Treatment Outcome , Young Adult
3.
J Dent Res ; 90(1): 35-40, 2011 Jan.
Article in English | MEDLINE | ID: mdl-21059869

ABSTRACT

The efficacy of the local application of recombinant human fibroblast growth factor-2 (FGF-2) in periodontal regeneration has been investigated. In this study, a randomized, double-blind, placebo-controlled clinical trial was conducted in 253 adult patients with periodontitis. Modified Widman periodontal surgery was performed, during which 200 µL of the investigational formulation containing 0% (vehicle alone), 0.2%, 0.3%, or 0.4% FGF-2 was administered to 2- or 3-walled vertical bone defects. Each dose of FGF-2 showed significant superiority over vehicle alone (p < 0.01) for the percentage of bone fill at 36 wks after administration, and the percentage peaked in the 0.3% FGF-2 group. No significant differences among groups were observed in clinical attachment regained, scoring approximately 2 mm. No clinical safety problems, including an abnormal increase in alveolar bone or ankylosis, were identified. These results strongly suggest that topical application of FGF-2 can be efficacious in the regeneration of human periodontal tissue that has been destroyed by periodontitis.


Subject(s)
Fibroblast Growth Factor 2/therapeutic use , Guided Tissue Regeneration, Periodontal/methods , Periodontitis/surgery , Adult , Alveolar Bone Loss/diagnostic imaging , Alveolar Bone Loss/surgery , Alveolar Process/drug effects , Dental Plaque Index , Double-Blind Method , Female , Fibroblast Growth Factor 2/administration & dosage , Follow-Up Studies , Gingiva/pathology , Gingival Hemorrhage/classification , Gingival Recession/classification , Humans , Male , Middle Aged , Periodontal Attachment Loss/classification , Periodontal Index , Periodontal Ligament/drug effects , Periodontal Pocket/classification , Placebos , Radiography , Recombinant Proteins , Surgical Flaps , Tooth Mobility/classification , Treatment Outcome
4.
Biosci Biotechnol Biochem ; 65(8): 1872-5, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11577732

ABSTRACT

Rats fed a diet containing beta1-4 linked galactooligosaccharides (GOS) (5 g/100 g of diet) absorbed calcium and magnesium more efficiently than those fed the control diet. However, the increment obtained through GOS-feeding was reduced by neomycin sulfate (0.67 g/100 g of diet). Since the decrease in cecal pH in rats fed GOS was suppressed by neomycin-feeding, bacterial action in the digestive tract was considered to be reduced by neomycin-feeding. Our findings suggest that the action of intestinal bacteria is necessary for the effects of GOS.


Subject(s)
Calcium/pharmacokinetics , Digestive System/microbiology , Intestinal Absorption/physiology , Magnesium/pharmacokinetics , Trisaccharides/metabolism , Animals , Anti-Bacterial Agents/pharmacology , Cecum/drug effects , Diet , Digestive System/metabolism , Feces/chemistry , Hydrogen-Ion Concentration , Male , Neomycin/pharmacology , Organ Size/drug effects , Rats , Rats, Inbred F344
5.
Antimicrob Agents Chemother ; 45(6): 1751-60, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11353622

ABSTRACT

The antimicrobial activity of the intraurethrally administered probiotic Lactobacillus casei strain Shirota against Escherichia coli in a murine urinary tract infection (UTI) model was examined. UTI was induced by intraurethral administration of Escherichia coli strain HU-1 (a clinical isolate from a UTI patient, positive for type 1 and P fimbriae), at a dose of 1 x 10(6) to 2 x 10(6) CFU in 20 microl of saline, into a C3H/HeN mouse bladder which had been traumatized with 0.1 N HCl followed immediately by neutralization with 0.1 N NaOH 24 h before the challenge infection. Chronic infection with the pathogen at 10(6) CFU in the urinary tract (bladder and kidneys) was maintained for more than 3 weeks after the challenge, and the number of polymorphonuclear leukocytes and myeloperoxidase activity in the urine were markedly elevated during the infection period. A single administration of L. casei Shirota at a dose of 10(8) CFU 24 h before the challenge infection dramatically inhibited E. coli growth and inflammatory responses in the urinary tract. Multiple daily treatments with L. casei Shirota during the postinfection period also showed antimicrobial activity in this UTI model. A heat-killed preparation of L. casei Shirota exerted significant antimicrobial effects not only with a single pretreatment (100 microg/mouse) but also with multiple daily treatments during the postinfection period. The other Lactobacillus strains tested, i.e., L. fermentum ATCC 14931(T), L. jensenii ATCC 25258(T), L. plantarum ATCC 14917(T), and L. reuteri JCM 1112(T), had no significant antimicrobial activity. Taken together, these results suggest that the probiotic L. casei strain Shirota is a potent therapeutic agent for UTI.


Subject(s)
Escherichia coli Infections/therapy , Lacticaseibacillus casei , Probiotics/therapeutic use , Urinary Tract Infections/therapy , Administration, Intravesical , Animals , Bacterial Adhesion/drug effects , Female , Mice , Models, Biological , Urinary Tract Infections/microbiology , Urinary Tract Infections/pathology
6.
Jpn Circ J ; 65(5): 395-8, 2001 May.
Article in English | MEDLINE | ID: mdl-11348042

ABSTRACT

Sixteen patients with mild to moderate heart failure were examined to investigate whether sympathetic deactivation plays a role in the improvement in the failing heart by chronic angiotensin converting enzyme (ACE) inhibition. Measurements, including echocardiography, blood examinations, neurohumoral samplings (atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), norepinephrine), and spectral heart rate variability analysis by Holter electrocardiography, were carried out before and 6 months after the administration of lisinopril (5-10 mg/day). Quality of life assessment was accomplished by the Specific Activity Scale (SAS) questionnaire. Treatment with lisinopril for 6 months resulted in a significant reduction in systolic blood pressure. The left ventricular diastolic dimension significantly decreased and fractional shortening significantly increased on echocardiography. Of the 16 patients, 8 had improvement in their symptoms as measured by the SAS. Lisinopril did not significantly reduce the plasma norepinephrine concentration, but there was a significant reduction in the plasma ANP and BNP concentrations. In the heart rate power spectral analysis, total spectral power, high-frequency components and low/high frequency ratios did not change significantly with lisinopril. The mechanism by which ACE inhibitors improve mild to moderate heart failure is not by suppressing sympathetic activity.


Subject(s)
Angiotensin-Converting Enzyme Inhibitors/pharmacology , Heart Failure/drug therapy , Lisinopril/pharmacology , Adult , Aged , Aged, 80 and over , Angiotensin-Converting Enzyme Inhibitors/therapeutic use , Echocardiography , Female , Heart/innervation , Heart/physiopathology , Heart Failure/physiopathology , Heart Rate/drug effects , Humans , Lisinopril/therapeutic use , Male , Middle Aged , Sympathetic Nervous System/drug effects , Sympathetic Nervous System/physiopathology
7.
Infect Immun ; 69(2): 1101-8, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11160007

ABSTRACT

We examined colonization patterns of Shiga toxin-producing Escherichia coli (STEC), concentrations of Shiga toxins (Stxs) and specific immunoglobulin A (lgA) against Stxs and STEC bacterial cell surface antigen in various portions of the gastrointestinal tract in an infant rabbit infection model. After inoculation of 3-day-old infant rabbits with STEC strain 89020087 at low doses (approximately 10(3) CFU/body), numbers of colonizing STEC bacteria and concentrations of Stxs in the intestine increased dramatically and the animals developed diarrhea within a couple of days after infection. Daily administration of Lactobacillus casei from the day of birth dramatically decreased the severity of diarrhea and lowered STEC colonization levels in the gastrointestinal tract 100-fold day 7 after infection. Both Stx1 and Stx2 concentrations in the intestines and histological damage to the intestinal mucus induced by STEC infection were decreased by the administration of L. casei. Examination of the concentrations of volatile fatty acids and pH of the intestinal contents revealed that the protective effect of L. casei administration against STEC infection was not due to fermented products such as lactic acid in the gastrointestinal tract. Administration of L. casei increased levels of lgAs against Stx1, Stx2, and formalin-killed STEC cells in the colon approximately two-, four-, and threefold, respectively, compared with those of the untreated controls by day 7 after infection. These results suggest that administration of L. casei strain Shirota enhances the local immune responses to STEC cells and Stxs and leads to elimination of STEC and thus decreases Stx concentrations in the intestines.


Subject(s)
Escherichia coli Infections/prevention & control , Escherichia coli O157/immunology , Lacticaseibacillus casei/physiology , Shiga Toxin/toxicity , Animals , Animals, Newborn , Antibodies, Bacterial/analysis , Digestive System/microbiology , Escherichia coli Infections/immunology , Escherichia coli Infections/pathology , Hydrogen-Ion Concentration , Lactic Acid/analysis , Lacticaseibacillus casei/immunology , Rabbits
8.
J Appl Microbiol ; 91(6): 985-96, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11851805

ABSTRACT

AIMS: The anti-infectious activity of Bifidobacteria in combination with transgalactosylated oligosaccharides (TOS) against Salmonella enterica serovar Typhimurium LT-2 in an opportunistic antibiotic-induced murine infection model in mice was examined. METHODS AND RESULTS: B. breve (strain Yakult) with natural resistance to streptomycin sulphate (SM, MIC: > 4 mg ml(-1)), when given daily at a dose of 108 cfu/mouse orally under SM treatment was constantly excreted at 10(10) cfu g(-1) faeces so long as SM was administered, even at 2 weeks after discontinuing administration of B. breve. Explosive intestinal growth and subsequent extra-intestinal translocation of orally infected LT-2 under SM treatment were inhibited by B. breve colonization, and this anti-infectious activity was strengthened by synbiotic administration of TOS with B. breve. Comparison of anti-Salmonella activity among several Bifidobacterium strains with natural resistance to SM revealed that strains such as B. bifidum ATCC 15696 and B. catenulatum ATCC 27539T conferred no activity, even when they reached high population levels similar those of effective strains such as strain Yakult and B. pseudocatenulatum DSM 20439. Both the increase in the concentration of organic acids and the lowered pH in the intestine due to bifidobacterial colonization correlated with the anti-infectious activity. Moreover, the crude cecal extract of B. breve-colonized mice exerted growth-inhibitory activity against LT-2 in vitro, whereas that of the ineffective B. bifidum-colonized cecum showed much lower activity. CONCLUSIONS: Intestinal colonization by bifidobacteria given exogenously together with TOS during antibiotic treatment prevents the antibiotic-induced disruption of colonization resistance to oral infection with S. enterica serovar Typhimurium, and the metabolic activity needed to produce organic acids and lower the intestinal pH is important in the anti-infectious activity of synbiotics against enteric infection with Salmonella. SIGNIFICANCE AND IMPACT OF THE STUDY: These results indicate that certain bifidobacteria together with prebiotics may be used for the prophylaxis against opportunistic intestinal infections with antibiotic-resistant pathogens.


Subject(s)
Bifidobacterium , Oligosaccharides/administration & dosage , Probiotics/administration & dosage , Salmonella Infections, Animal/immunology , Salmonella typhimurium/pathogenicity , Animals , Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/pharmacology , Cecum/microbiology , Disease Models, Animal , Feces/chemistry , Feces/microbiology , Humans , Male , Mice , Mice, Inbred BALB C , Oligosaccharides/pharmacology , Opportunistic Infections/chemically induced , Opportunistic Infections/microbiology , Probiotics/pharmacology , Salmonella Infections, Animal/chemically induced , Salmonella Infections, Animal/microbiology , Salmonella typhimurium/drug effects , Streptomycin/administration & dosage , Streptomycin/pharmacology
9.
Biosci Biotechnol Biochem ; 64(3): 466-75, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10803942

ABSTRACT

The effect of fermented skim milk (FSM) by Lactobacillus casei strain Shirota on plasma lipids in hamsters was examined. Hamsters fed on cholesterol-free and -enriched diets containing 30% FSM had lower levels of plasma triglyceride than those fed on the control diet. In the experiment with the cholesterol-enriched diet-fed hamsters, the plasma triglyceride level was suppressed by FSM at concentrations of 10% to 30%. Unfermented milk tended to lower the level of triglyceride, but not significantly. The plasma cholesterol concentration was not affected by an FSM and unfermented skim milk supplement to the diet. L. casei strain Shirota grew well in the presence of mixed lipid micelles containing bile acid, but did not have the ability to remove cholesterol from the culture broth. These results indicate that FSM lowered the plasma triglyceride level in hamsters.


Subject(s)
Lacticaseibacillus casei/metabolism , Milk , Triglycerides/blood , Animals , Cholesterol, Dietary/metabolism , Cricetinae , Feeding Behavior , Fermentation , Male , Mesocricetus , Milk/microbiology
10.
J Cardiovasc Pharmacol ; 35(3): 434-42, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10710130

ABSTRACT

Several antiarrhythmic agents with Na-channel blocking action have been shown to inhibit cardiac K(ATP) channels. We used cibenzoline to examine its precise target site using patch-clamp techniques and receptor binding assays in guinea-pig ventricular myocytes. Exposure of myocytes to a glucose-free perfusate containing 1 mM cyanide produced a time-dependent shortening of the action potential duration (APD) in the current-clamp mode. Cibenzoline (30 microM) slowed the development of APD shortening (APD90 to approximately 91% vs. approximately 55% control 16 min after metabolic inhibition) at pHo 7.4, but not at pHo 6.4 (to approximately 60%). The pinacidil (30 microM)-induced K(ATP) currents were inhibited by cibenzoline in a pHo-dependent manner: the higher the pHo, the stronger the blocking effect of cibenzoline. The binding of [3H]-labeled cibenzoline was prevented by cibenzoline, but not by glibenclamide. Alkalinization produces a higher concentration of the uncharged form of cibenzoline, which can more easily permeate the cell membrane than the charged form. In NIH3T3 cells stably expressing Kir6.1, a putative pore-forming subunit of K(ATP) channel, cibenzoline but not glibenclamide inhibited the K conductance. Thus cibenzoline interacts with the channel pore-forming subunit of the K(ATP) channel (Kir6.2), but not the sulfonylurea receptor, from the cytosolic side after it permeates into the cell interior via the membrane lipid bilayer.


Subject(s)
Action Potentials/drug effects , Anti-Arrhythmia Agents/pharmacology , Glyburide/pharmacology , Hypoglycemic Agents/pharmacology , Imidazoles/pharmacology , Potassium Channels/drug effects , Animals , Antihypertensive Agents/pharmacology , Cell Membrane Permeability , Cells, Cultured , Drug Interactions , Electrophysiology , Female , Guinea Pigs , Heart Ventricles/drug effects , Hydrogen-Ion Concentration , Male , Patch-Clamp Techniques , Pinacidil/pharmacology
11.
Jpn Circ J ; 62(10): 791-3, 1998 Oct.
Article in English | MEDLINE | ID: mdl-9805266

ABSTRACT

A 15-year-old female with Ebstein's anomaly was referred to hospital for radiofrequency (RF) current catheter ablation of her refractory paroxysmal supraventricular tachycardia (PSVT) after tricuspid valve replacement. A surface ECG showed ventricular preexcitation of type B Wolff-Parkinson-White (WPW) syndrome. In a baseline electrophysiological study, two types of PSVT with left and right bundle branch block (LBBB and RBBB) configurations were induced. The LBBB type was antidromic and the RBBB type was orthodromic atrioventricular reciprocating tachycardia (AVRT) with a right posterolateral accessory pathway. RF current was successfully delivered at the posterolateral site above the prosthetic valve (V-delta interval = -30 msec). The patient has been free from arrhythmias during a follow-up period of 9 months. RF current ablation seems to be useful for AVRT patients with corrected Ebstein's anomaly.


Subject(s)
Catheter Ablation , Ebstein Anomaly/physiopathology , Ebstein Anomaly/therapy , Adolescent , Electrophysiology , Female , Humans , Wolff-Parkinson-White Syndrome/physiopathology
12.
J Nutr Sci Vitaminol (Tokyo) ; 44(3): 473-81, 1998 Jun.
Article in English | MEDLINE | ID: mdl-9742467

ABSTRACT

We examined the effect of L-lactic acid on calcium absorption in male Wistar rats made achlorhydric by dietary omeprazole, a proton pump inhibitor. The dietary omeprazole intake (0.03 g/100 g of diet) increased the gastric pH and decreased the apparent calcium absorption ratio. Dietary famotidine (0.03 g/100 g of diet), an H2-receptor antagonist, and lower doses of omeprazole (0.005 or 0.01 g/100 g of diet) did not affect the gastric pH or the calcium absorption. In a second experiment, dietary lactic acid (0.5, 1.0, or 2.5 g/100 g of diet) increased the intestinal calcium absorption dose dependently in rats fed omeprazole (0.03 g/100 g of diet). The gastric pH was significantly decreased only in the rats fed higher doses of lactic acid (1.0, or 2.5 g/100 g of diet). In a third experiment, a dietary sour milk beverage containing lactic acid (0.5 g/100 g of diet) increased the intestinal calcium absorption, but did not affect the gastric pH in rats fed omeprazole (0.03 g/100 g of diet). Although the significance of gastric acid in terms of overall calcium absorption is not known, under the present experimental conditions, the inhibition of gastric acid secretion by dietary omeprazole decreased the apparent calcium absorption, and the dietary lactic acid prevented the calcium absorption in rats fed omeprazole.


Subject(s)
Calcium/metabolism , Enzyme Inhibitors/pharmacology , Intestinal Absorption/drug effects , Lactic Acid/pharmacology , Omeprazole/pharmacology , Animals , Diet , Gastric Acidity Determination , Lactic Acid/administration & dosage , Male , Omeprazole/administration & dosage , Proton Pump Inhibitors , Rats , Rats, Wistar
13.
J Nutr Sci Vitaminol (Tokyo) ; 44(6): 869-75, 1998 Dec.
Article in English | MEDLINE | ID: mdl-10197317

ABSTRACT

The effect of dietary L-lactic acid (LA), (0.5, 1.0, or 2.5 g/100 g of diet) on the absorption of calcium in gastrectomized rats was evaluated for 28 d. Calcium phosphate was used as a source of calcium. The apparent calcium absorption ratio and the calcium contents of the femur and tibia in gastrectomized rats fed the control diet were significantly less than those in sham-operated rats. In the gastrectomized rats, the apparent calcium absorption ratio and the calcium contents of bone in the rats fed the lower doses of LA diets (LA 0.5 or 1.0 g/100 g of diet) were not affected; however, the apparent calcium absorption ratio and the calcium contents of bone in the rats fed the highest doses of LA diet (LA 2.5 g/100 g of diet) were greater than those in gastrectomized rats fed the control diet. Dietary LA (2.5 g/100 g of diet) also enhanced the phosphorus absorption and bone phosphorus content in the gastrectomized rats. We speculated that the highest dose of dietary LA might be associated with the dissolving of a water-insoluble form of calcium salt in the diet, thereby facilitating the calcium absorption and resulting in increased bone calcium content in gastrectomized rats.


Subject(s)
Calcium/metabolism , Gastrectomy , Intestinal Absorption/drug effects , Lactic Acid/pharmacology , Animals , Body Weight , Calcium/analysis , Calcium Phosphates/administration & dosage , Eating , Femur/chemistry , Male , Phosphorus/analysis , Phosphorus/metabolism , Rats , Rats, Sprague-Dawley , Tibia/chemistry
14.
Circulation ; 96(9): 3129-35, 1997 Nov 04.
Article in English | MEDLINE | ID: mdl-9386185

ABSTRACT

BACKGROUND: The effects of angiotensin II (Ang II) on ATP-sensitive K+ channels (K(ATP)) were investigated in ventricular myocytes enzymatically isolated from adult guinea pig heart. METHODS AND RESULTS: In the whole-cell and cell-attached configurations (including open-cell-attached mode) of the patch-clamp technique, K(ATP) currents (I(KATP)) were activated through metabolic poisoning by the use of inhibitors of both glycolytic and oxidative ATP productions at 37 degrees C. In the whole-cell mode, I(KATP) were reversibly suppressed by increasing extracellular glucose and Ang II (1 nmol/L). In the cell-attached mode, Ang II concentration-dependently inhibited single K(ATP) activities with an IC50 value of 3.2+/-0.5 pmol/L (Hill coefficient=1.3+/-0.3). CV11974 (100 nmol/L), an angiotensin 1 (AT1) receptor-selective antagonist, blocked the inhibitory action of Ang II. Preincubation of myocytes with pertussis toxin (5 microg/mL for > 120 min at 37 degrees C) virtually prevented subsequent Ang II action. The inhibitory effect of Ang II was also abolished in the open-cell-attached mode (achieved by a prior perfusion of streptolysin-O, 0.08 U/mL). In this mode, through tiny membrane holes, the intracellular ATP concentration can be controlled by bathing extracellular solutions containing a known ATP concentration. CONCLUSIONS: The inhibitory actions of Ang II on K(ATP) appear to be mediated by an increase in the subsarcolemmal ATP concentration that results from the inhibition of adenylate cyclase activities via AT1 receptors/PTX-sensitive G proteins.


Subject(s)
Adenosine Triphosphate/metabolism , Angiotensin II/pharmacology , Heart/drug effects , Potassium Channels/drug effects , Adenosine Triphosphate/pharmacology , Animals , Female , GTP-Binding Proteins/physiology , Guinea Pigs , Male , Potassium Channels/physiology , Receptors, Angiotensin/drug effects
15.
Circ Res ; 81(2): 211-8, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9242182

ABSTRACT

Endothelin-1 (ET-1) is a 21-amino acid peptide hormone released from myocardial and endothelial cells, whose receptors (both ETA and ETB are expressed in the myocardium. We report here that ET-1 inhibits the cardiac delayed rectifier K+ current (IK) via a pertussis toxin (PTX)-sensitive mechanism. Ventricular myocytes enzymatically isolated from guinea pig hearts were voltage-clamped by the conventional whole-cell and nystatin-perforated patch technique (intrapipette and extrapipette K+ concentrations, 150 and 5.4 mmol/L, respectively) in the presence of nifedipine (2 mumol/L). Amplitudes of tail and steady state (2-second pulse) currents were measured as IK. ET-1 suppressed the basal IK by 20.9 +/- 2.3% in a concentration-dependent manner, with an IC50 of 1.1 +/- 0.3 nmol/L (n = 19), although it did not suppress the basal IK using the nystatin method. E-4031 (5 mumol/L), a blocker of the rapid component of IK (IKr), did not prevent the inhibitory action of ET-1. ET-1 reduced by 63.4 +/- 6.5% the slow component of IK (IKs) that had been enhanced to approximately 2-fold by isoproterenol (ISO, 20 nmol/L). The action was concentration dependent, with an IC50 of 0.7 +/- 0.4 nmol/L (n = 22), and was also observed using the nystatin method. The effect of ET-1 appeared to be mediated by an ETA receptor, because it was prevented by FR139317, an ETA-selective antagonist (1 mumol/L, n = 4), and sarafotoxin s6c, an ETB-selective agonist (100 nmol/L, n = 4), could not inhibit the ISO-enhanced IK. ET-1 antagonized IKs enhanced by histamine (250 nmol/L, n = 7) and forskolin (500 nmol/L, n = 7) but did not inhibit IKs enhanced by the internal application of cAMP (100 mumol/L, n = 6). Preincubation of myocytes with PTX (5 micrograms/mL for > 60 minutes at 36 degrees C) completely abolished the inhibitory action of ET-1 on the ISO-enhanced IKs (n = 4). Thus, nanomolar ET-1 inhibits IKs via the ETA receptor/PTX-sensitive G protein/PKA pathway.


Subject(s)
Endothelin-1/pharmacology , Pertussis Toxin , Potassium Channels/physiology , Potassium/physiology , Ventricular Function , Virulence Factors, Bordetella/pharmacology , Animals , Cells, Cultured , Drug Interactions , Guinea Pigs , Ion Transport/drug effects , Ion Transport/physiology , Patch-Clamp Techniques , Potassium Channels/drug effects
16.
J Nutr Sci Vitaminol (Tokyo) ; 43(3): 357-68, 1997 Jun.
Article in English | MEDLINE | ID: mdl-9268923

ABSTRACT

We studied the adaptational effect of galactooligosaccharide (GOS) on the concentration of organic acids in cecal content, fecal water content and organic acid production from GOS in cultures with the cecal inocula of rats fed GOS for 1, 2, 7 or 21 d. The fecal water content of rats fed GOS for 1 d was higher than that of the controls. The concentration of each organic acid in the cecal contents was affected by diet, not by the time of adaptation. In in vitro fermentation, lactic acid was produced by rapidly and remained in the cultures with homogenates of rats fed GOS for 1 d. Acetic acid in the cultures of the GOS-diet rats' cecal homogenates was produced more rapidly than that of the controls on days 2, 7 and 21 of adaptation. Propionic acid was produced more rapidly in the GOS homogenate cultures than in that of the controls on day 2. Butyric acid in the cultures from the GOS-fed rats was produced more rapidly than that of the controls on days 2 and 21. These results suggest that the time period of GOS feeding influenced the production rate of each organic acid, and the changes varied among acids.


Subject(s)
Bacteria/metabolism , Carboxylic Acids/metabolism , Cecum/microbiology , Trisaccharides/administration & dosage , Animals , Body Water/chemistry , Feces/chemistry , Feeding Behavior , Hydrogen-Ion Concentration , Kinetics , Male , Rats , Rats, Wistar , Weight Gain
17.
Jpn Circ J ; 61(3): 268-71, 1997 Mar.
Article in English | MEDLINE | ID: mdl-9152777

ABSTRACT

In this report we describe 2 patients with exercise-induced, second-degree atrioventricular (AV) block. Case 1 was a 49-year-old man with normal AV conduction at rest but who developed dyspnea on exertion. Treadmill testing showed an exercise-induced 2:1 AV block. Electrophysiologic study (EPS) demonstrated rate-dependent, presumably intrahissian, AV block. Case 2 was a 31-year-old woman with first-degree AV block and complete right bundle branch block with dyspnea on exertion and occasional syncope. She had twice undergone surgical patch closure of an ostium primum atrial septal defect. Exercise testing induced type II second-degree AV block. Atrial pacing during EPS did not disclose rate-dependent type II AV block, but disopyramide induced second-degree AV block.


Subject(s)
Exercise/physiology , Heart Block/etiology , Adult , Electrocardiography , Exercise Test , Female , Humans , Male , Middle Aged
18.
Int J Vitam Nutr Res ; 67(3): 201-6, 1997.
Article in English | MEDLINE | ID: mdl-9202982

ABSTRACT

The effects of commercially available calcium supplements (calcium carbonate, calcium gluconate, oyster shell preparation and bovine bone preparation) and gluconic acid on the absorption of calcium and magnesium were evaluated for 30 days in male Wistar rats. There were no differences in the apparent absorption ratio of calcium among rats fed each calcium supplement; however, the rats fed the calcium gluconate diet had a higher apparent absorption ratio of magnesium than the rats fed the other calcium supplements. Dietary gluconic acid also more markedly stimulated magnesium absorption than the calcium carbonate diet, and the bone (femur and tibia) magnesium contents of rats fed the gluconic acid diet were significantly higher than those of the rats fed the calcium carbonate diet. Furthermore, the weight of cecal tissue and the concentrations of acetic acid and butyric acid in cecal digesta of rats fed the calcium gluconate diet or the gluconic acid diet were significantly increased. We speculate that the stimulation of magnesium absorption in rats fed the calcium gluconate diet is a result of the gluconic acid component and the effect of gluconic acid on magnesium absorption probably results from cecal hypertrophy, magnesium solubility in the large intestine and the effects of volatile fatty acids on magnesium absorption.


Subject(s)
Calcium Gluconate/pharmacology , Calcium, Dietary/pharmacology , Magnesium/pharmacokinetics , Absorption/drug effects , Absorption/physiology , Animals , Body Weight/drug effects , Body Weight/physiology , Bone and Bones/chemistry , Calcium/pharmacokinetics , Calcium Carbonate/pharmacology , Cattle , Cecum/metabolism , Cecum/pathology , Eating/drug effects , Eating/physiology , Fatty Acids, Volatile/analysis , Femur/chemistry , Hydrogen-Ion Concentration , Hyperplasia , Magnesium/analysis , Magnesium/metabolism , Male , Phosphorus/pharmacokinetics , Rats , Rats, Wistar , Tibia/chemistry
19.
Cardiovasc Res ; 33(1): 123-30, 1997 Jan.
Article in English | MEDLINE | ID: mdl-9059535

ABSTRACT

OBJECTIVE: Secretion of endothelin-1 (ET-1) and activation of cardiac ATP-sensitive K+ (KATP) channels are facilitated under myocardial metabolic stress. The aim of this study was to investigate the effects of ET-1 on KATP channels and to assess underlying mechanisms in ventricular myocytes. METHODS: Single channel currents were measured with the voltage-clamp technique in cell-attached patches from enzymatically-isolated single guinea pig ventricular myocytes. In some experiments, the open-cell-attached mode was employed by permeating the membrane with streptolysin-O. RESULTS: ET-1 concentration-dependently inhibited single KATP channel currents, which had been activated by metabolic poisoning, with an IC50 of 3.8 +/- 0.7 pM. BQ-123, an ETA receptor-selective antagonist, reduced the effects of ET-1. ET-1 effects were largely abolished in the myocytes pre-incubated with pertussis toxin. In the open-cell-attached mode, where the intracellular ATP concentration ([ATP]) could be virtually controlled, the effects of ET-1 were abolished. Muscarinic receptor stimulation inhibited the channels in a similar manner to ET-1, whereas beta-adrenoceptor stimulation accelerated channel activation. By analogy, ouabain also inhibited KATP channel activity under metabolic stress presumably because inhibition of the Na+/K+ pump spares subsarcolemmal ATP. ET-1 inhibited the KATP channels that had been reactivated in the continuous presence of ouabain. CONCLUSIONS: ET-1 reversibly inhibited KATP channels. This effect appears to be mediated by an increase in subsarcolemmal [ATP] which results from inhibition of adenylate cyclase activities through PTX-sensitive G-proteins coupled to ETA receptors.


Subject(s)
Adenylate Cyclase Toxin , Endothelin-1/pharmacology , GTP-Binding Proteins/metabolism , Myocardium/metabolism , Pertussis Toxin , Potassium Channels/drug effects , Sodium-Potassium-Exchanging ATPase/metabolism , Virulence Factors, Bordetella/pharmacology , Adenosine Triphosphate/metabolism , Animals , Carbachol/pharmacology , Depression, Chemical , Endothelin Receptor Antagonists , Enzyme Inhibitors/pharmacology , Female , Guinea Pigs , Isoproterenol/pharmacology , Male , Muscarinic Agonists/pharmacology , Ouabain/pharmacology , Patch-Clamp Techniques , Peptides, Cyclic/pharmacology , Sympathomimetics/pharmacology
20.
Biosci Biotechnol Biochem ; 60(10): 1735-7, 1996 Oct.
Article in English | MEDLINE | ID: mdl-8987678

ABSTRACT

Magnesium deficiency was induced in male Wistar rats by adding an excess of phosphorous and calcium to the diet (1.195 g of phosphorous and 1.04 g of calcium/100 g of diet). Feeding of these animals with a diet containing beta 1-->4 linked galactooligosaccharides (4'-GOS) (5 g of 4'-GOS/100 g of diet) increased the apparent magnesium absorption ratios and the concentrations of magnesium in the serum and femur, and reduced accumulation of calcium in the kidney and heart. We speculate that the use of magnesium increased by feeding 4'-GOS to a limited extent prevented the lower magnesium status and the severity of calcification of the kidney and heart caused by excess dietary phosphorous and calcium.


Subject(s)
Calcinosis/metabolism , Calcium, Dietary/adverse effects , Galactose/analysis , Magnesium Deficiency/metabolism , Oligosaccharides/chemistry , Phosphorus, Dietary/adverse effects , Animals , Calcinosis/etiology , Carbohydrate Conformation , Carbohydrate Sequence , Intestinal Absorption , Kidney/metabolism , Magnesium Deficiency/etiology , Male , Molecular Sequence Data , Myocardium/metabolism , Rats , Rats, Wistar
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