Current status of antihypertensive therapy for elderly patients in Japan

To assess how elderly Japanese hypertensive patients are treated by specialists, we conducted a cross-sectional survey. A total of 1,163 outpatients aged 50 years or older were studied. Hypertension was diagnosed in 939 of these patients, and 827 were receiving drug therapy. The average blood pressure during therapy was 143 +/- 16/81 +/- 10 mmHg. In patients aged 70 years or older, systolic blood pressure during antihypertensive therapy was significantly higher (p < 0.01) and diastolic blood pressure was significantly lower (p < 0.01) than the corresponding values in those aged 50 to 59 years or 60 to 69 years. The calculated mean blood pressures were similar in the different age groups. The rate of monotherapy in the patients aged 70 years or older was 58.8%, which was significantly higher (p < 0.01) than the rates of monotherapy in the other age groups. Calcium channel blockers were prescribed in about 80% of patients, irrespective of age or comorbidity. Of the patients receiving calcium channel blockers, 43.5% were treated with monotherapy. This rate significantly (p < 0.01) increased with advancing age. Diastolic blood pressures were significantly lower (p < 0.05) in patients with stroke and in those with ischemic heart disease, diabetes mellitus, or dyslipidemia, as compared with patients with no comorbidity. Among patients aged 70 years or older, the difference in systolic blood pressure between those with ischemic heart disease and those with no comorbidity was not significant. Blood pressure in elderly hypertensive patients was reduced to a level similar to that in younger patients. The target blood pressure was influenced by the presence of comorbidity. Furthermore, specialists showed a high preference for the use of calcium channel blockers in the management of hypertension.

A pharmacological pilot study: application of an intermittent schedule of oral uracil and ftorafur (UFT) for hepatocellular carcinoma patients

Patients with hepatocellular carcinoma (HCC) are highly compromised by failing liver function. To retain good compliance in the administration of uracil and ftorafur (UFT) in such patients, an intermittent schedule for oral administration of UFT was expected to have the same effect as daily continuous use without affecting liver function. A pharmacological pilot study was carried out to confirm the efficacy of this schedule. Sixteen patients with HCC who underwent hepatectomy were given UFT 200 mg b.i.d. for five consecutive days. Blood samples were drawn before the last administration of UFT and at the operation (2 days after the last administration of UFT), and the tumor and adjacent liver tissue were collected. The concentration of ftorafur (FT), 5-fluorouracil (FUra) and uracil (Ura) in serum and liver tissue were measured. Oral administration of UFT 200 mg b.i.d. resulted in a trough level of FT, FUra and Ura in serum of 9.4 micrograms/ml, 13.3 ng/ml and 64.2 ng/ml, respectively. At the operation, FT and FUra in serum had decreased significantly. However, FUra in tissue was still higher than that in serum, in contrast to the results for FT and Ura. There was no difference in the concentration of FUra between the tumors and adjacent liver tissues. No side effect was noted in any of the patients. These results indicated that an intermittent schedule for the administration of oral UFT is not only tolerable but also effective because a sufficient concentration of FUra in the liver tissue is reached and maintained.

Intraluminal tumor of the common bile duct as a metastasis of renal cell carcinoma

A 57-year-old woman was admitted for evaluation of liver dysfunction. A physical examination revealed jaundice and a left abdominal mass, which was diagnosed as being a large renal tumor. Cholangiography showed a smooth filling defect 1 cm in diameter at the common bile duct. Left nephrectomy, and resection of the common bile duct were performed. The pathological diagnosis was metastasis of the common bile duct wall resulting from renal cell carcinoma. Metastatic common bile duct tumors are extremely rare. However, it is important to consider that this is one of the causes of obstructive jaundice.

Beneficial effects of angiotensin I converting enzyme inhibitor on post-ischemic contractile function of perfused rat heart

The present study was undertaken to determine whether trandolaprilat, an active form of angiotensin I converting enzyme (ACE) inhibitor, may improve ischemia/reperfusion-induced contractile dysfunction and metabolic derangement of isolated rat hearts. Ischemia (25 min) and subsequent 60-min reperfusion resulted in a small recovery of post-ischemic left ventricular developed pressure (LVDP), a sustained increase in left ventricular end-diastolic pressure, an increase in the release of creatine kinase and ATP metabolites from the perfused heart, and changes in myocardial sodium, potassium, calcium and magnesium contents. Treatment with 10-100 microM of trandolaprilat for the last 10 min of pre-ischemia recovered approximately 50-90% of pre-ischemic LVDP during reperfusion, whereas that with 30-100 microM of enalaprilat restored approximately 55-65% of the pre-ischemic LVDP. Treatment with either trandolaprilat or enalaprilat at these concentrations attenuated the release of creatine kinase and ATP metabolites into the perfusate during reperfusion. Treatment with 30 microM trandolaprilat suppressed ischemia/reperfusion-induced changes in myocardial ion content. Treatment with bradykinin during the last 10 min of pre-ischemia also resulted in a post-ischemic contractile recovery with a degree similar to that of the trandolaprilat-treated hearts. E4177, an AT1-antagonist, showed no effect on ischemia/reperfusion-induced changes in cardiac parameters. The enhancement of post-ischemic contractile recovery by the ACE inhibitor was abolished by treatment with either Hoechst 140, a bradykinin (BK2) antagonist, or diclofenac, a cyclooxygenase inhibitor. These results suggest that trandolaprilat is capable of attenuating ischemia/reperfusion injury of isolated perfused hearts and altered BK metabolism is, at least in part, involved in this effect.

Synthesis and structure-activity relationships of 6-substituted androst-4-ene analogs as aromatase inhibitors

Series of 6 alpha- and 6 beta-alkyl-substituted androst-4-en-17-ones (18 and 19) and their 17 beta-reduced derivatives (14 and 15)(alkyl: methyl, ethyl, n-propyl, n-pentyl, n-octyl) were synthesized and evaluated as aromatase inhibitors. Androst-4-en-17-ones having an oxygen function (hydroxy, acetoxy, or methoxy group) at C-6 alpha and C-6 beta (4 and 5) were also tested for their abilities to inhibit aromatase. All of the steroids studied inhibited human placental aromatase in a competitive manner. The inhibitory activities of the 6 alpha- and 6 beta-methyl-17-keto steroids 18a and 19a (Ki = 3.1 and 5.3 nM, respectively) as well as the 6 beta- alcohol 5a (Ki = 6.0 nM) were high, and their apparent Ki values were lower than that of the parent 6-unsubstituted 3-deoxy steroid 1 (Ki = 6.8 nM). Elongation of the methyl group decreased affinity for aromatase in relation to carbon number of the alkyl chain in each series, in which the 6 alpha- alkyl steroids 18 essentially had higher affinity for the enzyme than the corresponding 6 beta- isomers 19. The inhibitory activities of the 17 beta-hydroxy analogs 14 and 15 were less potent than those of the corresponding 17-keto steroids. The 6 alpha-ethyl compound 18b, the 6 alpha-oxygenated derivatives 4, and the 6 beta-acetoxy and 6 beta-methoxy analogs 5b and 5c were powerful inhibitors (Ki = 12-24 nM). The methyl steroids (18a and 19a) produced "type I" difference spectra upon interaction with aromatase. These results along with molecular modeling with the PM3 method suggest that compounds 18a and 19a may produce a thermodynamically stable enzyme-inhibitor complex in the hydrophobic binding pocket with a limited accessible volume. A carbonyl group at C-17 of the 6-alkylandrost-4-enes is essential for the tight binding. Moreover, the binding pocket also tolerates a polar hydroxy group at the 6 beta-position rather than at the 6 alpha-position.

Evaluation of surgical resection for small hepatocellular carcinomas

BACKGROUND

The surgical results for small hepatocellular carcinomas (HCCs) are not necessarily satisfactory. The resectional therapy for small HCC was evaluated to elucidate its benefits and limitations.

PATIENTS AND METHODS

Data were analyzed concerning 52 patients having small HCC of <3 cm in diameter and <3 nodules, who underwent hepatic resections from 1978 to 1989.

RESULTS

Cumulative and disease-free survival at 5 years after resection were 57% and 37%, respectively. Histologic features, such as differentiation of HCCs, pseudocapsular invasion, and ploidy pattern of nuclear DNA, appeared to be good prognostic indicators. The survival rate of the large-resection group (number of resected segments greater than number of tumor-occupying segments) was significantly better than that in the small-resection group (84% versus 48% at 5 years, P<0.05).

CONCLUSIONS

Surgical resection of small HCCs is a safe and effective therapy. A large resection appears to provide better patient survival and tumor-free survival compared to a small resection.

Effects of aprindine on ischemia/reperfusion-induced cardiac contractile dysfunction of perfused rat heart

The present study was undertaken to determine whether aprindine, a class Ib antiarrythymic agent, exerts beneficial effects on ischemia/reperfusion-induced cardiac contractile dysfunction and metabolic derangement. Isolated rat hearts were subjected to 35-min global ischemia, followed by 60-min reperfusion, and functional and metabolic alterations of the heart were determined with or without aprindine-treatment. Ischemia induced a cessation of left ventricular developed pressure (LVDP), a rise in left ventricular end-diastolic pressure (LVEDP), and an increase in myocardial sodium content and a decrease in myocardial potassium content. When the hearts were reperfused, little recovery of LVDP and sustained rise in LVEDP and perfusion pressure were observed. Ischemia/reperfusion resulted in a release of ATP metabolites and creatine kinase from perfused hearts, an increase in myocardial sodium and calcium contents, and a decrease in myocardial potassium and magnesium contents. Treatment of the perfused heart with either 10 or 30 microM aprindine for the last 3 min of pre-ischemia improved contractile recovery during reperfusion and suppressed changes in myocardial ion content during ischemia and reperfusion. Treatment with the agent also attenuated the release of ATP metabolites and creatine kinase from the heart. However, treatment with high concentrations of aprindine (70 and 100 microM) improved neither cardiac contractile dysfunction, myocardial ionic disturbance nor the release of ATP metabolites and creatine kinase during reperfusion. Two possible mechanisms for the cardioprotection by the agent have been suggested: suppression of transmembrane flux of substrates and enzymes, and prevention of accumulation of myocardial sodium during ischemia.

Ischemic hepatitis in cirrhosis. clinical features and prognostic implications

To characterize liver dysfunction in patients with cirrhosis after variceal bleeding, we analyzed 50 cirrhotic patients who had bleeding esophageal varices with or without shock. Increases in serum total bilirubin levels by 1.5 times were observed within 24 h in 11 of 12 patients with shock who died > 4 days after hemorrhage but in only one of eight patients with shock who survived (p < 0.01). Increases in serum aspartate aminotransferase and alanine aminotransferase by 2.5 times were observed in six patients in the former group but in none of the latter (p < 0.05). In postmortem livers, hepatocellular degeneration with minimal inflammatory cell infiltration was observed. Ischemic hepatitis is frequently noted in cirrhotic patients with ruptured esophageal varices. Patients with increases in the serum level of total bilirubin and/or aminotransferases within 24 h from onset of hemorrhage should be carefully treated even if hemorrhage is controlled.

Water jet scalpel for liver resection in hepatocellular carcinoma with or without cirrhosis

Patients with hepatocellular carcinoma were subjected to hepatic resection by using a water jet scalpel which is a device developed recently. Seventy-two patients who underwent hepatic resection were divided into two groups: group A included patients with HCC associated with liver cirrhosis and group B included patients without cirrhosis. Patient characteristics and liver function tests did not differ significantly between the groups. Resected a specimens weighed lighter in group A than in group B. No significant difference in total blood loss, time of operation and postoperative complications were noted. Physiologic saline employed in the machine to create a fine jet stream was projected through the nozzle on the liver at a pressure of 15-20 kg/cm2. The parenchyma of the cirrhotic liver was divided but the intrahepatic vessels were spared. It was therefore concluded that hepatic resection by water jet is safe and useful in case of HCC associated with cirrhosis of the liver.

Ice-based altitude distribution of natural radiation annual exposure rate in the Antarctica zone over the latitude range 69 degrees S-77 degrees S using a pair-filter thermoluminescence method

Both ice-based altitude distributions of natural ionizing radiation exposure and the quasi-effective energy of natural radiation over Antartica over the latitude range 69 degrees S - 77 degrees S during approx. 500 days were measured using thermoluminescent dosimeters. The results shows that dependence on altitude above sea level of the exposure rate increases by almost three-fold with each increase of 2000 m of altitude, thus deviating from the general rule stating that the exposure rate should double with each 2000 m. Although the exposure rate shows a dependence on altitude, altitude dependence of the quasi-effective energy of natural radiation over Antartica is not observed. In the present study it is observed that natural radiation occurring over the ice base of Antartica consists mainly of cosmic rays.

Monamidocin, a novel fibrinogen receptor antagonist. II. Biological activity and structure-activity relationships

Monamidocin, a fibrinogen receptor binding inhibitor produced by Streptomyces sp. NR 0637, inhibits the binding of fibrinogen to its receptor with an IC50 of 0.21 microM. It also inhibits ADP-collagen- and thrombin-induced aggregation of human platelet with IC50S of 46, 30, and 77 microM, respectively. To obtain more potent inhibitors, twenty analogs have been synthesized, among which N-[(R)-5-guanidino-2-hydroxypentanoyl]-L-tyrosine is the most potent. It inhibits the binding of fibrinogen to its receptors with an IC50 of 0.022 microM and is about ten times more potent than monamidocin.

Monamidocin, a novel fibrinogen receptor antagonist. I. Production isolation, characterization and structural elucidation

Monamidocin, a novel fibrinogen receptor antagonist, has been isolated from the culture broth of Streptomyces sp. NR 0637 BY carbon adsorption, n-BuOH extraction, SP-Toyopearl, silica gel 60 silanised and Sephadex LH-20 column chromatographies and preparative HPLC. The molecular formula of monamidocin has been determined to be C15H22N4O4 from HRFAB-MS and 13C NMR spectral data. The structure of monamidocin has been determined to be N-[(S)-5-guanidino-2-hydroxypentanoyl]-L-phenylalanine by 2D NMR experiments.

[Two hepatocellular carcinoma patients with biloma after transarterial embolization with lipiodol (Lip-TAE) leading to occlusion of portal vein]

We presented two patients with post-Lip-TAE biloma resulting in portal occlusion, and reviewed 20 previous studies including our cases to investigate their clinical characteristics. Case 1. A 31-year-old woman suffered from an HCC located at the S8 segment, and had a superselective embolization of feeding arteries using 3 ml of Lip, 300 mg of CBDCA, and 40 mg of Epi-Adriamycin (Epi-ADM). Eleven weeks later, CT showed multiple cystic lesions, and the percutaneous transhepatic drainages of the lesions were established. At 21 weeks after Lip-TAE, we found occlusion of the right branch of portal vein on CT, but she recovered from this condition, and was discharged 1 year later. Case 2. A 62-year-old man was diagnosed as HCC located at S7-6 segments, and was infused with 3 ml of Lip, 150 mg of CBDCA, and 30 mg of Epi-ADM through a right hepatic artery. Ten weeks later, CT showed a cystic lesion in the S7-8 segments, occlusion of the right anterior segmental branch of the portal vein, and the same drainage was also established. Unfortunately, he died of liver failure 18 weeks later. In the literature, biloma after Lip-TAE occurred at 71.2 mean days, ranging from 7 to 180 days, a with remarkable increase in biliary tree-associated enzymes. Seven (35%) of 20 patients died of liver failure or sepsis during 3 weeks and 1 year, and 3 (60%) of 5 patients accompanied by occlusion of a certain portal branch frequently died. We consider that these patients need intensive care and should be under long follow-up.

Sulfobacins A and B, novel von Willebrand factor receptor antagonists. II. Structural elucidation

Sulfobacins A and B are novel von Willebrand factor (vWF) receptor antagonists produced by Chryseobacterium sp. NR 2993. The structures of sulfobacins A and B have been determined to be (2R,3R)-3-hydroxy-2-[(R)-3-hydroxy-15-methylhexadecanamido]-15- methylhexadecanesulfonic acid and (2R,3R)-3-hydroxy-15-methyl-2-[13-methyltetradecanamido]- hexadecanesulfonic acid, respectively, by various 2D NMR experiments and by methanolysis. The absolute configurations of the sulfobacins were determined by a modified MOSHER's method. The structures are related to sulfonolipids, major components of the cell envelope of gliding bacteria of the genus Cytophaga.

Sulfobacins A and B, novel von Willebrand factor receptor antagonists. I. Production, isolation, characterization and biological activities

Sulfobacins A and B, novel von Willebrand factor (vWF) receptor antagonists, have been isolated from the culture broth of Chryseobacterium sp. (Flavobacterium sp.) NR 2993 by ethyl acetate extraction, and by Sephadex LH-20 and silica gel column chromatographies. The physico-chemical properties of the sulfobacins indicate that their structures are completely different from that of aurintricarboxylic acid, the one known vWF receptor antagonist. Sulfobacins A and B inhibit the binding of vWF to its receptor with IC50S of 0.47 and 2.2 microM, respectively. Sulfobacin A also inhibits ristocetin-induced agglutination in human platelets fixed with paraformaldehyde with an IC50 of 0.58 microM.

[Advantages and disadvantages of the intraarterial chemotherapy using a reservoir as postoperative adjuvant therapy for hepatocellular carcinoma]

We conducted a retrospective study on the efficacy and disadvantages of intraarterial chemotherapy using a reservoir (ICUR), as postoperative adjuvant therapy for hepatocellular carcinoma (HCC). One hundred and seventy HCC patients who underwent hepatectomy since 1987 to 1992 in our institute were enrolled in this study. Ninety-two patients were postoperatively treated with ICUR (group R), and seventy-eight patients without it (group N). There were no significant differences between the two groups in the preoperative evaluations of the characteristics of patients, tumors, and operative procedures. Although statistical significances were not found, disease-free rates within 1 year and cumulative survival rates appeared to be higher in group R than in group N. Patency of the catheter of reservoirs at one and two years were maintained in 80.3 and 44.1% of the patients, respectively. HCC recurred after an occlusion of the reservoir in 18 patients. In four out of these 18 patients, transcatheter arterial embolization (TAE) for recurrent tumors was not feasible, because of occlusion of the hepatic artery. TAEs for recurrent lesions would have been impossible in about 10% of all patients treated with ICUR. Thus, both the advantages and disadvantages should be taken into consideration on the indication of ICUR, and the maintainance of the catheter is important for successful ICUR.

Design of an antifungal methionine inhibitor not antagonized by methionine

Only a few biosynthetic pathways in fungal cells have been used as antifungal targets. Therefore, the number of antifungals has been limited, and a cross-drug resistance among them has emerged in the therapy of mycoses. Under such circumstances, the identification of an antifungal with a new mode of action is highly desirable. By infecting mice with a mutant of C. albicans deficient in the sulfate assimilation pathway, we have discovered a new target for the discovery of antifungal agents. We have proven that azoxybacilin inhibits the sulfate assimilation pathway by showing its inhibitory activity for [35S]SO4 incorporation into proteins. We have also demonstrated that azoxybacilin was taken up into fungal cells via an active transport system specific for methionine. This sharing of the uptake system with methionine may explain the mechanism by which the antifungal activity of azoxybacilin is antagonized by methionine, and led us to design azoxybacilin derivatives that lack the structural feature of amino acids and, at the same time, have increased hydrophobicity to give higher non-specific permeability through the cell membrane. As a result, we have found that ester derivatives of azoxybacilin were not antagonized by methionine in their uptake, and that they showed antifungal activity independent of methionine. The benzyl ester of azoxybacilin was the same as azoxybacilin in its mode of action, but was not markedly antagonized by methionine at concentrations up to 1 mg/ml. These results suggest that azoxybacilin may not merely interfere with the sulfate assimilation pathway.

[Effects of intraarterial chemotherapy after hepatectomy in hepatic cancer patients]

We conducted a retrospective study on the effects of intra-hepatic arterial chemotherapy in patients with liver cancer, and 118 patients with stage II hepatocellular carcinoma (HCC) who had undergone hepatectomy were enrolled. Patients were divided into three groups: group R (n = 41) was treated by intraarterial infusion of Epi-adriamycin 30-40 mg/body and CDDP 100 mg/body via reservoir every two weeks post-operatively; group O (n = 57) was given one-shot infusion of Epi-adriamycin or adriamycin, and group N (n = 20) served as the control. No significant differences were observed among the three groups in postoperative disease-free survival rates. The better prognosis of survival rates found in group R suggested the influence of treatment on the recurrent lesions. Six of 14 long-term survivors were in group N. The selection of the patients group should be studied more in order to obtain the full potential of postoperative intraarterial chemotherapy in stage II HCC.

Effects of N-(2-mercaptopropionyl)-glycine on postischemic contractile function in ischemic/reperfused hearts. Dissociation of thiobarbiturate-reacting substance formation and contractile dysfunction

The present study was undertaken to determine whether N-(2-mercaptopropionyl)-glycine, a membrane-permeable antioxidant agent, improves the ischemia/reperfusion-induced cardiac contractile dysfunction. Rat isolated hearts were subjected to a 35 min global ischemia, followed by a 60 min reperfusion. Ischemia/reperfusion did not result in the recovery of postischemic left ventricular developed pressure. Reperfusion markedly increased the content of the thiobarbiturate-reacting substance in the myocardium. Treatment of the perfused heart with 1 mM of N-(2-mercaptopropionyl)-glycine, either during a 30 min pre-ischemia or during a 30 min pre-ischemia and the first 10 min of reperfusion, resulted in an appreciable recovery of the postischemic left ventricular developed pressure and an attenuation of the increase in thiobarbiturate-reacting substance content. When hearts were treated with the same concentration of the agent only during the first 10 min of reperfusion, the cardiac contractile function was not improved during reperfusion despite the increase in thiobarbiturate-reacting substance content of the reperfused myocardium. These results suggest that the increase in thiobarbiturate-reacting substance content during reperfusion is independent of the postischemic contractile failure.

A possible involvement of sodium channel blockade of class-I-type antiarrhythmic agents in postischemic contractile recovery of isolated, perfused hearts

The present study was undertaken to test the hypothesis that the degree of sodium channel blockade by class-I-type antiarrhythmic agents accounts for enhancement of postischemic contractile recovery of ischemic/reperfused hearts. Electrophysiological studies showed that the class-I-type antiarrhythmic agents quinidine, disopyramide, procainamide, lidocaine, mexiletine, flecainide and pilsicainide suppressed the Vmax value of the rat left ventricular muscle cell, a marker of sodium channel blockade, in a concentration-dependent manner. Isolated rat hearts were subjected to 35 min of ischemia and 60 min of reperfusion. Postischemic contractile recovery, which was never detected in untreated hearts, was enhanced in hearts pretreated with these antiarrhythmic agents during the last 3 min before ischemia at concentrations ranging from 3 to 300 microM. Tissue Na, but not Ca, accumulation was also detected in the ischemic heart, and tissue Na and Ca accumulation was observed in the reperfused heart, which suggests that sodium overload occurs during ischemia, followed by sodium and calcium overload during reperfusion. The degree of postischemic contractile recovery seen in the presence of these antiarrhythmic agents was inversely related to tissue Na or Ca accumulation after reperfusion, which suggests that class-I-type antiarrhythmic agents inhibit sodium overload occurring in ischemic/reperfused myocardial cells. A close relationship between postischemic contractile recovery of the perfused heart and depression in the Vmax value of the ventricular muscle was also observed. These results suggest that the ability class-I-type antiarrhythmic agents to inhibit myocardial sodium channels plays a significant role in the enhancement of postischemic contractile recovery of the ischemic/reperfused heart.

Effects of one-year cadmium exposure on livers and kidneys and their relation to glutathione levels

To study the effects of a long-term cadmium exposure on livers and kidneys, rats were administered cadmium chloride (0.228 mg Cd/kg, 3 days/week ip), for one year. Significant accumulation of cadmium was observed in livers (183 +/- 40 micrograms/g liver) and kidneys (92 +/- 17 micrograms/g kidney). Serum urea nitrogen and creatinine levels were significantly elevated in the cadmium-treated rats, while liver function tests were minimally affected. Histological observations showed interstitial fibrosis with minimal cell necrosis and inflammatory cell infiltration in livers, and apparent degeneration of proximal tubules and infiltration of inflammatory cells in parenchyma of kidneys. Lipid peroxidation in livers and kidneys, as assessed by thiobarbituric acid reactive substances, revealed no differences between the cadmium-treated rats and the controls. Glutathione contents were significantly increased in the cadmium treated rats both in livers (p < 0.001), and in kidneys (p < 0.001) compared with the controls. Increased glutathione levels in livers may contribute, in part, to the prevention of serious hepatotoxicity during chronic cadmium exposure, while nephrotoxicity due to cadmium may not be prevented by glutathione.

Mexiletine and lidocaine reduce post-ischemic functional and biochemical dysfunction of perfused hearts

The present study was undertaken to determine whether class Ib antiarrhythmic agents, mexiletine and lidocaine, exert beneficial effects on ischemia/reperfusion-induced cardiac contractile dysfunction. Isolated rat hearts were subjected to 35-min global ischemia, followed by 60-min reperfusion and the functional and metabolic alterations were examined with and without mexiletine or lidocaine treatment. Ischemia/reperfusion resulted in a lack of recovery of contractile function, a sustained rise in left ventricular end-diastolic pressure and increased coronary perfusion pressure of the perfused heart during reperfusion. Contractile dysfunction was associated with increases in tissue Na+ and Ca2+ levels, decreases in K+ and Mg2+ levels, and release of creatine kinase and purine nucleosides and bases (ATP metabolites) from the heart. Treatment of the perfused heart with either 10-100 microM of either mexiletine or lidocaine during pre-ischemia resulted in an enhancement of post-ischemic contractile recovery, a suppression of changes in tissue Na+, K+, Ca2+ and Mg2+ contents and an attenuation of the release of creatine kinase and ATP metabolites in an almost concentration-dependent manner. Tissue sodium accumulation was observed at the end of ischemia, which was also attenuated by pretreatment with these agents. The prevention of Na+ overload and accompanying Ca2+ overload in cardiac cells may be the mechanism underlying the improvement of post-ischemic contractile function of perfused hearts by these agents.