Maternal liver damage delays meiotic resumption in bovine oocytes through impairment of signalling cascades originated from low p38MAPK activity in cumulus cells.

The main objective of the present study is to investigate the molecular mechanism underlying the delay in progression of nuclear maturation in oocytes derived from cows with damaged livers (DL cows), which was previously reported. In present study, delayed progression of nuclear maturation of oocytes derived from DL cows relative to oocytes derived from cows with healthy livers (HL cows) was accompanied by low maturation promoting factor (MPF) activity (0.43 fold, p < 0.05). When cumulus cells were removed from cumulus-oocyte complexes and the denuded oocytes were cultured, there was no difference in the progression of nuclear maturation between the two liver conditions. In addition, gap junctional communication (GJC) between the oocyte and cumulus cells was higher in DL cows than in HL cows at 3 and 7 h of in vitro maturation (IVM) (p < 0.05). Supplementation of IVM medium with epidermal growth factor (EGF) increased the ratio of germinal vesicle breakdown (GVBD) of oocytes derived from DL cows to the level seen in oocytes derived from HL cows. Additionally, the level of p38MAPK phosphorylation at 0 h of IVM was significantly lower in cumulus cells derived from DL cows than in cumulus cells derived from HL cows (HL cows, 53.5%; DL cows, 28.9%; p < 0.05). Thus, a low level of p38MAPK phosphorylation in cumulus cells induced slow GJC closure between oocyte and cumulus cells, which resulted in slow meiotic maturation of oocytes derived from DL cows.

Age-associated changes in gene expression and developmental competence of bovine oocytes, and a possible countermeasure against age-associated events.

In general, maternal age affects the quality of oocytes and embryos. The present study aimed to examine the features and age-associated gene expression profiles of bovine oocytes and embryos as well as to discover possible countermeasures against age-associated events. Comprehensive gene expression assays of germinal vesicle and metaphase II (MII)-stage oocytes and 8- to 16-cell-stage embryos were conducted using next-generation sequencing technology. The gene expression profiles of aged cows showed high expression of genes related to oxidative phosphorylation, eIF4 and p70S6K signaling, and mitochondrial dysfunction in MII-stage oocytes. Oocytes derived from aged cows, compared with those derived from their younger counterparts, exhibited high levels of abnormal fertilization and blastocysts with low total cell numbers. Levels of reactive oxygen species (ROS) and SIRT1 were higher in in vitro-matured oocytes derived from aged cows than in those derived from their younger counterparts. Supplementation of maturation medium with N-acetyl-cysteine (NAC), but not resveratrol, reduced the levels of ROS in the oocytes derived from cows of both age groups; however, resveratrol, but not NAC, improved the fertilization ratio. Conversely, EX 527, an inhibitor of SIRT1, increased the ratio of abnormal fertilization. In conclusion, gene expression profiles of oocytes and embryos derived from aged cows differ from those of oocytes and embryos derived from young cows; in particular, oocytes derived from aged cows show protein and mitochondrial dysfunction. In addition, activation of SIRT1 in oocytes may be a potential countermeasure against age-associated events in oocytes derived from aged cows.

A phase II study of palonosetron combined with dexamethasone to prevent nausea and vomiting induced by highly emetogenic chemotherapy.

BACKGROUND: This is a randomized, double-blind, dose-ranging study in patients receiving highly emetogenic chemotherapy (HEC) to evaluate the safety, efficacy, and pharmacokinetics of palonosetron, in combination with dexamethasone. MATERIALS AND METHODS: We randomized 233 patients to receive palonosetron as a single i.v. bolus dose of 0.075, 0.25, or 0.75 mg before administration of HEC. Dexamethasone (12-16 mg i.v. on day 1, 8 mg i.v. on day 2, and 4-8 mg i.v. on day 3) was administered for prophylactic antiemesis. Pharmacokinetics of palonosetron was analyzed in 24 patients. RESULTS: In this study, all patients were given > or =50 mg/m(2) cisplatin, which was considered to be HEC. No significant differences in complete response (CR: no emesis and no rescue medication) rates were found in the first 24 h between the 0.075-, 0.25-, and 0.75-mg groups (77.6%, 81.8%, and 79.5%, respectively). In the 120-h period of overall observation, CR rates increased in a dose-dependent manner. In the 0.75-mg group, we observed a significantly longer time to treatment failure than in the 0.075-mg group (median time >120 versus 82.0 h, P = 0.038). Palonosetron was tolerated well and did not show any dose-related increase in adverse effects. CONCLUSIONS: Palonosetron at doses of 0.25 and 0.75 mg was shown to be effective in preventing chemotherapy-induced nausea and vomiting with high CR rates of patients treated with HEC in Japan. All tested doses of palonosetron were tolerated well.

Lorlatinib for the treatment of patients with non-small cell lung cancer.

Lorlatinib is a novel third-generation tyrosine kinase inhibitor (TKI) which targets anaplastic lymphoma kinase (ALK) as well as receptor tyrosine kinase c-ros oncogene 1 (ROS1). A critical limitation of conventional ALK/ROS TKIs is their association with acquired resistance mutations (particularly ALK G1202R and ROS1 G2032R) in the ALK or ROS1 gene, although these are not the only resistance mechanisms. Another limitation of this class of drugs is their inadequate efficacy against central nervous system metastasis, likely attributable to the blood-brain barrier (BBB). Therefore, lorlatinib was developed to overcome these limitations by being more potent, selective and permeable to the BBB than previous-generation ALK/ROS1 TKIs and subsequently received breakthrough therapy designation from the U.S. Food and Drug Administration (FDA) in April 2017. In September 2018, Japan became the first country where lorlatinib received approval for treating patients with ALK-rearranged non-small cell lung cancer. Eventually, the FDA approved lorlatinib (Lorbrena; Pfizer) in November 2018. Lorlatinib use is expected to increase in importance, owing to its promising efficacy in clinical trials.

Preservation of mitochondrial function may contribute to cardioprotective effects of Na+/Ca2+ exchanger inhibitors in ischaemic/reperfused rat hearts.

BACKGROUND AND PURPOSE: Na+/Ca2+ exchanger (NCX) inhibitors are known to attenuate myocardial reperfusion injury. However, the exact mechanisms for the cardioprotection remain unclear. The present study was undertaken to examine the mechanism underlying the cardioprotection by NCX inhibitors against ischaemia/reperfusion injury. EXPERIMENTAL APPROACH: Isolated rat hearts were subjected to 35-min ischaemia/60-min reperfusion or 20-min ischaemia/60-min reperfusion. NCX inhibitors (3-30 microM KB-R7943 (KBR) or 0.3-1 microM SEA0400 (SEA)) were given for 5 min prior to ischaemia (pre-ischaemic treatment) or for 10 min after the onset of reperfusion (post-ischaemic treatment). KEY RESULTS: With 35-min ischaemia/60-min reperfusion, pre- or post-ischaemic treatment with KBR or SEA neither enhanced post-ischaemic contractile recovery nor attenuated ischaemia- or reperfusion-induced Na+ accumulation and damage to mitochondrial respiratory function. With the milder model (20-min ischaemia/reperfusion), pre- or post-ischaemic treatment with 10 microM KBR or 1 microM SEA significantly enhanced the post-ischaemic contractile recovery, associated with reductions in reperfusion-induced Ca2+ accumulation, damage to mitochondrial function, and decrease in myocardial high-energy phosphates. Furthermore, Na+ influx to mitochondria in vitro was enhanced by increased concentrations of NaCl. KBR (10 microM) and 1 microM SEA partially decreased the Na+ influx. CONCLUSIONS AND IMPLICATIONS: The NCX inhibitors exerted cardioprotective effects during relatively mild ischaemia. The mechanism may be attributable to prevention of mitochondrial damage, possibly mediated by attenuation of Na+ overload in cardiac mitochondria during ischaemia and/or Ca2+ overload via the reverse mode of NCX during reperfusion.

Inhibitor of vascular endothelial growth factor receptor tyrosine kinase attenuates cellular proliferation and differentiation to mature neurons in the hippocampal dentate gyrus after transient forebrain ischemia in the adult rat.

Neurogenesis in the adult hippocampal dentate gyrus is promoted by transient forebrain ischemia. The mechanism responsible for this ischemia-induced neurogenesis, however, remains to be determined. It has been suggested that there may be a close relationship between neurogenesis and the expression of vascular endothelial growth factor, an angiogenic factor. The purpose of the present study was to examine the relationship between vascular endothelial growth factor and cell proliferation in the dentate gyrus after transient forebrain ischemia. The mRNA expression of vascular endothelial growth factor was increased in the dentate gyrus on day 1 after ischemia. Immunohistochemical analysis on day 9 after ischemia, when a significant increase in cell proliferation was seen, showed that the cerebral vessel space in the subgranular zone of the dentate gyrus had not been affected by the ischemia. Neither were the vascular densities on days 1 and 3 after ischemia altered compared with those of non-operated naïve control rats. Furthermore, the distance from the center of the proliferative cells to the nearest cerebral vessel of ischemic rats was comparable to that of the sham-operated rats. We demonstrated that transient forebrain ischemia-induced cell proliferation and differentiation to mature neurons in the hippocampal dentate gyrus was attenuated by the i.c.v. administration of a vascular endothelial growth factor receptor tyrosine kinase inhibitor. These results suggest that vascular endothelial growth factor receptor at the early period of reperfusion may contribute to neurogenesis rather than to angiogenesis in the hippocampal dentate gyrus.

Role of tumor-associated macrophages in lung cancer.

The percentage of tumor-associated macrophages recovered (TAMR) and antitumoral activity of tumor-associated macrophages (TAM) were examined in 77 patients with resectable primary lung cancer. TAM was obtained by plastic adherence following trypsinization. TAMR increased from Stage I to Stage II and decreased in Stage III. It also increased in N1 as compared with N0 and N2 but was unrelated to tumor size. However, the cytostatic activity of TAM declined with advance in stage of the disease and an increase of tumor size, but it was relatively unaffected by the presence of metastasis to regional lymph nodes. There was no correlation between TAMR and the recurrence rate; however, cytostatic activity of TAM was correlated significantly with the prognosis of totally resected cases. TAMR and cytostatic activity of TAM tended to be lower in palliatively resected cases. These results suggest that the assessment of the antitumor activity of TAM, but not merely TAMR, may give prognostic information for lung cancer patients.

Antitumor activity of pleural cavity macrophages and its regulation by pleural cavity lymphocytes in patients with lung cancer.

Antitumor activities of pleural cavity macrophages (PCM) and pleural cavity lymphocytes (PCL) in lung cancer patients were examined. The effect of coculture supernatants of PCL and autologous tumor cells on the cytostatic activity of macrophages was also examined. Cytostatic activity of PCM was not affected by an advance of metastasis to regional lymph nodes or increase of tumor size and difference of histological type. However, the cytostatic activity of PCM was markedly augmented when pleural invasion was limited to within the visceral pleura although it was low when pleural invasion was absent or extended beyond the visceral pleura. On the other hand, PCL did not exert any cytolytic activity against various tumor target cells. However, coculture supernatants of PCL and autologous tumor cells exhibited the activity of macrophage-activating factor against guinea pig peritoneal macrophages. Furthermore, the higher the cytostatic activity of PCM, the higher the macrophage-activating factor activity of the coculture supernatant of PCL and autologous tumor cells was. These results suggested that antitumor activity of PCM was controlled by specifically sensitized PCL through lymphokines.

Antitumor activity of macrophages in lung cancer patients with special reference to location of macrophages.

Antitumor activity of macrophages from the peripheral blood, pleural cavity, and alveoli of 35 patients with primary lung cancer was examined. Cytostatic activities of peripheral blood monocytes and alveolar macrophages from either tumor-bearing or non-tumor-bearing segments declined in association with metastasis to regional lymph nodes, an increase in tumor size, and the development of pleural invasion. However, no such correlation could be observed between the cytostatic activity of pleural cavity macrophages and the degree of pleural invasion. The cytostatic activity of pleural cavity macrophages was found to be suppressed when the pleural invasion extended beyond the visceral pleura to the neighboring lobe or chest wall. On the other hand, the cytostatic activity of pleural cavity macrophages was markedly augmented when pleural invasion was limited to within the visceral pleura, although it was low in patients with no visceral pleural invasion. These results suggest that the pleural cavity is isolated from sites of systemic immunological response and that systemic immunological response does not strongly affect pleural cavity macrophages.

Role of energy metabolism in the preconditioned heart--a possible contribution of mitochondria.

A brief period of ischemia and reperfusion has been shown to protect the myocardium against subsequent sustained ischemia and reperfusion injury, which is called "preconditioning". A great number of investigators have explored the mechanisms underlying this preconditioning-induced cardioprotection. This article dealt with possible mechanisms of energy metabolism and mitochondrial activity for preconditioning-induced cardioprotection. Particularly, the contribution of energy metabolites produced during a brief period of ischemia and reperfusion injury, as well as mitochondrial function that is modified by changes in mitochondrial ATPase activity, opening of mitochondrial ATP-dependent potassium channels and production of free radicals in mitochondria, to ischemic preconditioning is discussed.

Preconditioning preserves mitochondrial function and glycolytic flux during an early period of reperfusion in perfused rat hearts.

OBJECTIVE: The purpose of the present study was to examine the effects of preconditioning on glycolysis and oxidative phosphorylation during reperfusion in perfused rat hearts. METHODS: Preconditioning was induced by 5 min of ischemia and 5 min of reperfusion before 40 min of sustained ischemia and subsequent 30 min of reperfusion. Tissue energy metabolite levels, mitochondrial oxygen consumption capacity and adenine nucleotide translocator content of the perfused hearts were assessed at 40 min of ischemia, 5 and 30 min of reperfusion. RESULTS: Preconditioning improved the postischemic recovery of rate x pressure product (92.5 +/- 8.7 vs. 24.9 +/- 1.2% for non-preconditioned group) and high-energy phosphate content (ATP and CrP; 39.5 +/- 2.0 and 96.2 +/- 4.9% of initial vs. 24.1 +/- 0.9 and 56.1 +/- 4.3% of initial for the non-preconditioned group). The mitochondrial oxygen consumption capacity and the adenine nucleotide translocator content of the non-preconditioned heart were decreased by sustained ischemia and remained decreased throughout reperfusion. Preconditioning prevented these decreases. The tissue lactate level of the non-preconditioned heart was high throughout reperfusion (16.5-fold vs. basal), whereas in the preconditioned heart it returned to the basal level within a few minutes of reperfusion. Furthermore, the ratios of [fructose 1,6-bisphosphate]/([glucose 6-phosphate] + [fructose 6-phosphate]) at 5-min reperfusion were higher (2.2-fold) than those of the non-preconditioned heart. CONCLUSIONS: The results suggest that preconditioning preserves the capacity for normal mitochondrial function and the facilitation of glycolysis during reperfusion, which may play an important role in the improvement of postischemic contractile function and high-energy phosphate content.

Characterization of cardiac myocyte and tissue beta-adrenergic signal transduction in rats with heart failure.

OBJECTIVE: The cellular basis of alterations in beta-adrenergic signal transduction in rats with chronic heart failure (CHF) remains unclear. The aim of the present study was to examine this signal transduction system in isolated ventricular cardiomyocytes of rats with CHF. We focused on changes in the levels of stimulatory (Gs) and inhibitory G-proteins (Gi). METHODS: CHF was induced in male Wistar rats by coronary artery ligation (CAL). Hemodynamic and biochemical parameters were measured 8 weeks after CAL. Alterations in contractile function and Ca(2+) transients via beta-adrenergic receptor signaling of cardiomyocytes isolated from rats with CHF were characterized by simultaneous measurements of cell shortening and fura-2 fluorescence intensity. RESULTS: Coronary artery-ligated rats showed symptoms of CHF, such as decreased contractile function, increased left ventricular volume, decreased chamber stiffness, and about 40% infarct formation of the left ventricle, by 8 weeks after surgery. The contractile function and Ca(2+) dynamics of cardiomyocytes from the rats with CHF remained normal under basal conditions. Only cardiac cell length was increased. The responses of peak shortening, fura-2 fluorescence ratio amplitude, and cAMP content to beta-adrenoceptor stimulation were reduced in cardiomyocytes of the rats with CHF, whereas direct stimulation of adenylate cyclase did not affect the response of these variables. Cardiomyocyte Gsalpha protein was decreased, whereas no changes in Gialpha proteins were seen in these cells. Increases in tissue Gsalpha and Gialpha proteins in the scar zone were detected. The results on tissue levels of collagen and G-proteins in the viable left ventricle appeared to depend on the presence of nonmyocytes. CONCLUSIONS: The results suggest that impaired contractile function of cardiomyocytes is unlikely to account for global LV contractile dysfunction, and that down-regulation of beta-adrenoceptors occurs in cardiomyocytes per se. The difference in changes of G-protein between the cardiomyocyte and myocardial tissue suggests an appreciable contribution of nonmyocytes to myocardial G-protein levels.

Long-term treatment with neutral endopeptidase inhibitor improves cardiac function and reduces natriuretic peptides in rats with chronic heart failure.

OBJECTIVE: Increased secretion of atrial and brain natriuretic peptide (ANP and BNP) from hearts is known to exhibit favorable effects in patients and animals with heart failure, and inhibition of neutral endopeptidase (NEP), an enzyme that degrades ANP and BNP, may further increase these peptide levels. However, it is still unknown whether such elevation of the ANP and BNP may offer a therapeutic benefit to the progression of chronic heart failure (CHF). We examined the effects of ONO-9902, a novel NEP inhibitor, on changes in hemodynamic parameters, NEP activity and neurohumoral factors in rats with CHF induced by left coronary artery ligation (CAL). METHODS: Male Wistar rats (220-240 g) were subjected to induction of acute myocardial infarction by CAL. Rats were orally treated with ONO-9902 (300 mg/kg/day) from the 1st to 6th week after the operation. Hemodynamic and/or biochemical assessments were performed at the 1st and 6th weeks after the operation. RESULTS: A single administration of ONO-9902 inhibited the plasma and kidney NEP activities and thereby further augmented the elevation of plasma ANP concentration in rats with CAL at the 1st week after the operation. In rats with CAL at the 6th week after the operation, the left ventricular end-diastolic pressure (LVEDP) increased and cardiac output index (COI) decreased as compared with those of sham-operated rats. These changes were accompanied by marked increases in the plasma ANP, BNP and endothelin-1 (ET-1). Chronic treatment with ONO-9902 attenuated the increase in LVEDP and the decrease in COI. These changes were associated with a decrease in plasma ANP, BNP and ET-1 concentrations. CONCLUSIONS: The results suggest that chronic treatment with NEP inhibitor improves depressed cardiac function in rats with CHF. ONO-9902 may offer a new and possible therapeutic approach in patients with CHF.

Functional changes of aorta with massive accumulation of calcium.

The present study was undertaken to elucidate pathophysiological changes and functional alterations of the calcified artery. For this purpose, rats were treated with 500,000 units/kg vitamin D3, and tension development of isolated rat aortae was examined. Treatment of rats with vitamin D3 resulted in an increase (approx. 64-fold) in the tissue calcium. Light microscopic examination of the aorta after staining with hematoxylin-eosin and von Kossa indicated numerous plaques in the aortic media. The results indicate a massive accumulation of calcium in the aortic media. Responsiveness of the calcified tissue to norepinephrine, epinephrine, serotonin, prostaglandin F2 alpha was found to be 11-66% when compared to that of the control. Furthermore, the calcified tissue responded minimally to isoproterenol and acetylcholine, which elicited a relaxation in control aortae. Isoproterenol-induced relaxation of the calcified aorta after 100 mM KCl contracture was also diminished. In the present study we have demonstrated poor responsiveness of the calcified aorta to physiological and pharmacological substances relative to normal tissue, which implies a functional damage of the artery upon massive calcium accumulation.

Serum antibody production by oral immunization with dextran B512.

Serum antibodies to dextran were detected when dextran B512 was orally administered to C3H/He mice. The amounts of serum antibodies were increased along with the dose of orally administered dextran B512. For serum antibody production, differences were observed among the strains of mice. C3H/He, C57BL/6 and CBA mice produced high levels of serum antibodies to dextran, while BALB/c and DBA/2 mice produced low levels of serum antibodies. The serum antibodies had groove-type combining sites, as determined by ELISA inhibitory assay.

Succinate dehydrogenase in Plasmodium falciparum mitochondria: molecular characterization of the SDHA and SDHB genes for the catalytic subunits, the flavoprotein (Fp) and iron-sulfur (Ip) subunits.

Mitochondria of malaria parasites generate a membrane potential through an electron transport system that is a possible target of primaquine and a new anti-malarial drug, atovaquone. However, little information is available for conclusive understanding of the respiratory chain in Plasmodium mitochondria. In the present study, we cloned and characterized from Plasmodium falciparum the genes for the catalytic subunits, SDHA for the flavoprotein (Fp) and SDHB for iron-sulfur protein (Ip), of succinate-ubiquinone oxidoreductase (complex II), which is a marker enzyme for mitochondria and links the TCA cycle and respiratory chain directly. Each of the two genes contains a single open reading frame (ORF), which are located on different chromosomes, 1860 nucleotides on chromosome 10 for SDHA and 963 nucleotides on chromosome 12 for SDHB. The expression of these genes in asynchronous erythrocytic stage cells was confirmed by observation of 3.3 and 2.4 kb transcripts from the SDHA and SDHB genes, respectively. The SDHA and SDHB genes encode proteins of 620 (Fp) and 321 (Ip) amino acids with molecular masses of 69.2 and 37.8 kDa, respectively. A mitochondrial presequence essential for the import of mitochondrial proteins encoded by nuclear DNA, as well as almost all the conserved amino acids indispensable for substrate binding and the catalytic reaction were found in these peptides, indicating the functional importance of this enzyme in the parasite. Interestingly, a P. falciparum-specific insertion and a unicellular organism-specific deletion were found in the amino acid sequence of Fp. This is the first report of the primary structure of the protozoan succinate dehydrogenase.

Impairment of cerebral cAMP-mediated signal transduction system and of spatial memory function after microsphere embolism in rats.

The transcription factor cAMP-responsive element binding protein (CREB) has been implicated in synaptic plasticity and memory. The purpose of the present study was to characterize alterations in the cAMP/protein kinase A (PKA)/CREB system after sustained cerebral ischemia. Sustained cerebral ischemia was induced by injection of 900 microspheres (48 microm in diameter) into the right (ipsilateral) hemisphere of rats. Alterations in the CREB, PKA, and cAMP levels in the cerebral cortex and hippocampus were examined up to 7 days after microsphere embolism. Immunoblotting analysis showed a decrease in the immunoreactivity of phosphorylated CREB (pCREB) in the ipsilateral hemisphere on the third day after microsphere embolism, whereas that of the total CREB was not altered. An electrophoretic gel mobility shift assay showed a decrease in the cAMP response element (CRE)-DNA binding activity of CREB in the ischemic region on the third day after the microsphere embolism. Cytosolic PKA C beta in the ipsilateral hemisphere was selectively decreased on the first day after the microsphere embolism, whereas the levels of another catalytic subunit, C alpha, and a regulatory subunit, RII alpha, were not altered. Immunoreactivity of the PKA catalytic subunit C alpha in the nucleus of the ipsilateral hemisphere was decreased on the third day after the embolism. The decreases in the pCREB, CRE-DNA binding activity, and PKA C alpha and C beta levels lasted at least up to 7 days after the operation. A decrease in the cAMP content was also seen in the ipsilateral hemisphere throughout the experiment. Furthermore, microsphere embolized rats showed prolongation of the escape latency in the water maze task determined on the seventh to ninth day after the operation. Our results suggest that sustained cerebral ischemia may impair the phosphorylation and CRE-DNA binding activity of CREB and that these effects may be one of the possible causes for learning and memory dysfunction.

Effects of naftidrofuryl oxalate on microsphere embolism-induced decrease in regional blood flow of rat brain.

1. The purpose of the present study was to determine whether naftidrofuryl oxalate (naftidrofuryl), a vasodilator, is capable of improving brain regional blood flow of animals in sustained ischaemia. 2. Cerebral ischaemia was induced by injecting 900 microspheres (48 microns in diameter) into the right internal carotid artery of rats. Cerebral blood flow of brain regions was measured by a hydrogen clearance method on the 3rd, 7th and 28th days after the onset of ischaemia. Ischaemic animals were treated with naftidrofuryl, 15 mg kg-1 day-1 i.p., from the first to 28th day. 3. Microsphere-embolism caused a sustained decrease in cortical and striatal blood flow over a period of 28 days, whereas hippocampal blood flow was decreased on the 3rd day but not on the 7th or 28th day. On the 3rd day, the striatal and hippocampal but not cortical blood flow of naftidrofuryl-treated, microsphere-embolized rats was higher than untreated rats. On the 7th and 28th days, the cortical and striatal blood flow of the treated and untreated animals did not differ. 4. Brain slices from microsphere-embolized rats contained areas, which were not stained with triphenyltetrazolium chloride (TTC), to a similar degree on the 3rd, 7th and 28th days, indicating the genesis of cerebral infarction. TTC-unstained areas of microsphere-embolized rats that had received naftidrofuryl treatment were smaller than those of untreated rats on the 3rd and 7th days, but not on the 28th day. 5. The results suggest that naftidrofuryl improves cerebral circulation impaired by microsphere-induced ischaemia and this higher level of cerebral blood flow of the treated animal may account for the delayed development of cerebral infarction.

Beneficial effect of beraprost, a prostacyclin-mimetic agent, on post-hypoxic recovery of cardiac function and metabolism in rabbit isolated hearts.

1. The present study was undertaken to determine whether beraprost, a stable prostacyclin-mimetic agent, may exert a beneficial effect on post-hypoxic recovery of cardiac function and metabolism. Isolated rabbit hearts were perfused by the Langendorff method for 20 min under glucose-free hypoxic conditions, followed by 45 min reoxygenation in the presence of glucose, and their functional and metabolic changes with or without beraprost-treatment were examined. 2. Hypoxic insult induced cessation of cardiac contractile force, depletion of myocardial high-energy phosphates, accumulation of tissue calcium, and release of creatine kinase and ATP metabolites. Subsequent reoxygenation resulted in a poor recovery of cardiac contractile force (less than 10% of the pre-hypoxic value), a poor restoration of high-energy phosphates, and increase in calcium content. A further release of creatine kinase and ATP metabolites from the heart was observed during reoxygenation. 3. Treatment with 0.45 microM beraprost during the whole hypoxic period resulted in a significant suppression of the increase in tissue calcium, and the release of creatine kinase and ATP metabolites during hypoxic perfusion. This treatment also elicited a significant post-hypoxic recovery of the cardiac contractile force and the tissue high-energy phosphates. Reoxygenation-induced release of creatine kinase and ATP metabolites was also prevented by treatment with beraprost. 4. When hearts were treated with prostacyclin sodium (0.50 microM) in the same manner for the purpose of comparison, similar improvement of post-hypoxic contractile and metabolic recovery were observed. 5. These results demonstrate that treatment with either beraprost or prostacyclin is beneficial for post-hypoxic recovery of cardiac function and metabolism. Since the observed effects on post-hypoxic contractile recovery were exerted at a concentration of approximately 0.50 microM of these agents (a concentration far from the physiological range) the underlying mechanism appears to be different from the physiological action of prostacyclin.