Risk factors for thrombocytopenia and analysis of time to platelet transfusion after azacitidine treatment

The use of azacitidine (AZA) has been known to lead to a high incidence of hematotoxic adverse events. The aims of this study were to identify the risk factors for thrombocytopenia after the administration of AZA and to analyze time to the initial platelet transfusion. Sixty-two patients with myelodysplastic syndrome (MDS), who were treated with AZA in Gifu Municipal Hospital between March 2012 and June 2020, were included in this study. The risk factors for thrombocytopenia were identified using univariate analysis of patient characteristics, disease type, and laboratory values immediately before the start of treatment. Variables with p<0.2 identified in the univariate analysis were used as independent variables in the multivariate analysis. This analysis identified "creatinine clearance (CCr) <60 mL/min" as a significant factor (odds ratio, 4.790; 95% confidence interval [CI], 1.380-16.70; p=0.014). Subsequently, time in days to the initial platelet transfusion after the initial administration of AZA was analyzed using the log-rank test. The overall median time in days to platelet transfusion was 370 days. The log-rank test was used to determine the influence of patient characteristics, disease type, and laboratory values immediately before the start of treatment. The subsequent Cox proportional hazard regression analysis using variables with p<0.2 as independent variables identified "hemoglobin (Hb) <8.0 g/dL" as a significant factor (hazard ratio, 2.143; 95% CI, 1.001-4.573; p=0.048). The results of this study led to the following clinical implications: first, patients with CCr of <60 mL/min at the start of treatment should be treated with caution due to the risk of thrombocytopenia. Second, patients with Hb of <8.0 g/dL at the start of treatment may require platelet transfusion in the early stage of treatment.

Effects of polypharmacy on the prevalence of adverse drug events resulting in outpatient visits and hospitalization

A high proportion of hospitalizations is attributable to the prevalence of adverse drug events. This retrospective study included outpatients and inpatients to determine the prevalence of adverse drug events and if polypharmacy increases it. The prevalence, classification, and causality of adverse drug events were assessed based on medical records, laboratory values, and other data. Multivariate analysis (multiple logistic regression analysis) was performed with the presence or absence of adverse drug events at the time of the visit as the dependent variable and items for which the P-value was <0.25 in the univariate analysis as independent variables. The prevalence of adverse drug events was 13.0%, 10.9%, and 16.0% among all patients, the outpatient group, and the inpatient group, respectively. Multivariate analysis showed that polypharmacy (≥5 drugs) significantly increased the risk of adverse drug events in all patients. The prevalence of adverse drug events significantly increased with each additional drug used. We expect that minimizing the number of medications through moderation of the number of prescription drugs and elimination of polypharmacy will reduce the number of outpatient visits and hospitalizations due to adverse drug events.

Cost utility analysis of pharmacist counseling care for breast cancer chemotherapy outpatients

Chemotherapy for cancer is increasingly implemented in the outpatient setting. Pharmacists contribute to cancer treatment by conducting counseling during outpatient chemotherapy visits. They provide guidance on drug treatment, side effects, and side effect countermeasures on every visit. However, there have been few economic evaluations of pharmacist involvement in outpatient chemotherapy. Therefore, we performed a cost utility analysis. We assigned usual care (control) and pharmacist counseling to two groups of 19 patients receiving outpatient chemotherapy for breast cancer at Gifu Municipal hospital. Quality of life was measured at three timepoints before and during chemotherapy treatment using the EuroQol 5 dimension instrument (EQ-5D). EQ-5D values across the timepoints were 0.831, 0.757, and 0.791 for the control group, and 0.882, 0.883, and 0.921 for the pharmacist counseling group. The additional cost in the pharmacist counseling group was 2,227 yen per counseling session. The change in quality-adjusted life years (QALY) was a maximum of -0.021±0.186 in the control group and 0.007±0.199 in the pharmacist counseling group. The maximum cost for one QALY was 1,360,558 yen (≈12,460 US dollars). Pharmacists' counseling in outpatient cancer chemotherapy for breast cancer patients had an acceptable incremental cost-effect ratio, contributing to improved patient quality of life without significant additional expenditure to healthcare.

Relationship Between Initial Renal Function and the Inhibitory Effect of Dipeptidyl Peptidase-4 Inhibitor Treatment on Renal Function Decline

We retrospectively investigated the renal function index of patients with type 2 diabetes mellitus (T2DM) to examine the influence of dipeptidyl peptidase-4 (DPP-4) inhibitors on renal function between patients up to early nephropathy and after overt nephropathy. Patients with T2DM (>18 years old) who had been prescribed hypoglycemic agents for ≥3 months at Gifu Municipal Hospital between March 2010 and April 2014 were included in the study. Renal function was evaluated as the estimated glomerular filtration rate (eGFR) decline from baseline at 12 months. Patients in the DPP-4 inhibitor-treated and untreated groups with an eGFR ≥60 (358 [58.2 %] and 257 [41.8 %], respectively) and eGFR <60 (115 [60.2 %] and 76 [39.8 %], respectively) were subjected to multiple logistic regression analysis. Among patients with an eGFR ≥60, no significant differences were observed in eGFR decline rates over time. However, among patients with an eGFR <60, significant decreases were observed in eGFR decline rates >10 % (6 months; odds ratio, 0.476; P = 0.043, 12 months; odds ratio, 0.413; P = 0.010). Similar results were obtained for an eGFR decline rate >20 % (12 months; odds ratio, 0.369; P = 0.049). DPP-4 inhibitors are renoprotective in patients with T2DM and an eGFR <60.

Factors influencing the use of over-the-counter drugs and health foods/supplements

Over-the-counter (OTC) drugs and health foods/supplements are used as means of self-medication with the aim of preventing diseases and maintaining health. No reports have yet addressed the relationship between healthcare systems and self-medication. Here, we carried out a retrospective survey to identify healthcare system factors affecting OTC drug and health food/supplement usage. Patients hospitalized at Gifu Municipal Hospital between October 1, 2014 and March 31, 2015 were given a survey. The items surveyed were age, gender, disease, alcohol intake/smoking status, insurance classification, and medical pharmaceuticals, OTC drugs, and health foods/supplements used immediately before hospitalization. We performed multiple logistic regression analysis using OTC drugs and health foods/supplements as dependent variables with patient attributes, medical insurance, etc. as independent variables. A total of 5,965 patients were analyzed. OTC users comprised 2.6 % (156 people) of the total. The use of OTC drugs was significantly higher for females and alcohol consumers than in other categories. In contrast, the use of OTC drugs was significantly lower for participants in public expense/medical subsidy programs. Health foods/supplements were used by 4.0 % of all subjects (240 people); their use was significantly higher among females and users of medical pharmaceuticals. On the other hand, the use of health foods/supplements was significantly lower for smokers, users of the latter-stage elderly healthcare system, and users of public expense/medical subsidy programs.

Hyponatremia and hypokalemia as risk factors for falls

BACKGROUND/OBJECTIVES

Fall accidents may reduce an individual's quality of life and ability to perform the activities of daily life, and may delay recovery from illness. Consequently, medical institutions need to take measures to prevent falls. There are various risk factors for falls, including advanced age, illness and medication effects. Although hyponatremia and hypokalemia have been reported to increase the rate of falls, how they affect falls is not fully understood.

SUBJECTS/METHODS

We retrospectively examined 2948 patients, ⩾18 years old who had been hospitalized for ⩾3 days at Gifu (Japan) Municipal Hospital between May 2012 and April 2013 to determine the effects of hyponatremia and hypokalemia on the risk of falls. After the patients had been divided into fall and non-fall groups, their data were subjected to univariate and multiple regression analysis to identify significant differences.

RESULTS

The univariate analysis results revealed significant differences between the groups in terms of age (⩾65 years); the presence of hyponatremia, hypokalemia, central nervous system disease, cardiovascular disease and/or peripheral nerve/muscular disease; intake of medications that increase the risk of falls; and increased sedative dosage. The multivariate analysis results revealed significant differences between the groups in terms of the presence of hyponatremia (odds ratio (OR), 1.751; 95% confidence interval (CI), 1.020-3.005), hypokalemia (OR, 2.209; 95% CI, 1.280-3.813), central nervous system disease (OR, 2.492; 95% CI, 1.629-3.814) and/or age ⩾65 years (OR, 2.180; 95% CI, 1.242-3.826).

CONCLUSIONS

The results indicated that the presence of hyponatremia or hypokalemia increases the risk of falls.

Impact of levofloxacin dose adjustments by dispensing pharmacists on adverse reactions and costs in the treatment of elderly patients

Ensuring an appropriate dosage of renally eliminated drugs for patients with renal insufficiency is important for preventing adverse drug reactions. We investigated the effectiveness of interventions by pharmacists in a hospital pharmaceutical department. The comparative study was performed at Gifu Municipal Hospital in Japan from March to August 2011, and included an intervention (142 patients) and a control group (98 patients). Upon receiving a prescription of levofloxacin for patients aged > or = 75 years, pharmacists evaluated the patients' kidney function and adjusted the appropriate dosage at the time of dispensation. In the intervention and control groups, levofloxacin-induced adverse reactions developed in 6 of 142 (4.2%) and 13 of 98 (13.3%) patients, respectively (p < 0.05). The cost of reducing levofloxacin per patient was yen 191.1 and yen 0 in the intervention and control groups, respectively. The cost per patient for adverse reaction treatments and examinations was yen 15.5 and yen 290.0 in the intervention and control groups, respectively. The intergroup difference in the total cost per patient was yen 465.6. Dose adjustment of levofloxacin at the time of dispensation by the pharmacist for patients aged > or = 75 years resulted in a decrease in the incidence of adverse reactions and cost. These findings can be applied not only to hospitals, but also to community pharmacies, because the intervention, which is a manual system, is simply performed when pharmacists are dispensing drugs.

Pharmacoeconomic analysis of DPP-4 inhibitors

Dipeptidyl peptidase-4 (DPP-4) inhibitors and other incretin-related drugs have attracted attention as antidiabetic agents, but they are expensive. The Japanese government has adopted a policy of reducing healthcare costs, and medical institutions must provide medical care while considering economic efficiency. This study was a comparative survey of the usage, treatment effectiveness, and cost of DPP-4 inhibitors. The subjects were patients prescribed DPP-4 inhibitors (sitagliptin, vildagliptin, and alogliptin) at Gifu Municipal Hospital between February 2010 and August 2011. HbA1c: Japan Diabetes Society values (%) and concomitant antidiabetic agents were surveyed for 12 weeks after the start of DPP-4 inhibitors. A cost-effectiveness analysis showed that the cost required for a 0.1% decrease in HbA1c for 12 weeks was the lowest with vildagliptin (2,478 yen; decrease in HbA1c: 0.75% +/- 0.85%). In a cost analysis with a virtual cohort of 1000 patients, the number of patients who achieved the treatment target (HbA1c 6.5%) was estimated with respect to a virtual cohort created based on the HbA1c level (7.59 +/- 1.13%) at baseline of 307 patients, in cases assuming the use of each DPP-4 inhibitor. In addition, the incremental cost-effectiveness ratio (ICER) was obtained with sitagliptin 50 mg as the reference. The number of patients achieving the treatment target was the highest with vildagliptin 100 mg (413 of 1000 patients), and the estimated ICER of 28,359 yen was the lowest. Robustness was also confirmed with a sensitivity analysis. These results suggest that vildagliptin provides a superior cost-benefit.

Risk factors for Clostridium difficile-associated diarrhea and the effectiveness of prophylactic probiotic therapy

Measures for prevention of Clostridium difficile-associated diarrhea, a common nosocomial infection, in hospital settings are urgently needed. This study was conducted to identify the risk factors contributing to C. difficile-associated diarrhea and to evaluate the clinical benefit of probiotics in its prevention. The study included 2716 patients at least 20 years old who received an injected antibiotic at any time between February 2010 and February 2011; a total of 2687 patients (98.9%) were assigned to the non-C. difficile-associated diarrhea group, and 29 patients (1.1%) were assigned to the C. difficile-associated diarrhea group. Univariate analysis revealed a significant difference between the two groups for the following factors: antibiotic therapy for > or = 8 days; enteral nutrition; intravenous hyperalimentation; fasting; proton pump inhibitor use; H2 blocker use; and serum albumin < or = 2.9g/dL (p<0.05). Multivariate logistic regression analysis revealed a significant difference between the two groups for several factors. Antibiotic therapy for > or = 8 days, intravenous hyperalimentation, proton pump inhibitor use, and H2 blocker use were therefore shown to be risk factors for C. difficile-associated diarrhea. Prophylactic probiotic therapy was not shown to suppress the occurrence of C. difficile-associated diarrhea.

Effects of a single arthrocentesis and a COX-2 inhibitor on disorders of temporomandibular joints

Our aim was to examine the short-term effect of combined treatment with single arthrocentesis and a COX-2 inhibitor on 26 patients with severe symptoms of temporomandibular joint (TMJ) disorders. The severity of the disorders was graded according to the degree of restriction of mouth opening and pain score on a visual analogue scale. Synovial fluid was collected from the superior joint space of the affected TMJ, and arthrocentesis was done with isotonic saline, 200ml. Subsequently, etodolac, 400mg/day, was given for 2 weeks. At 14 days, patients were re-examined and further specimens of synovial fluid were collected. Patients generally lost their symptoms and the severity of the disorders improved significantly (P<0.01). The concentrations of total protein and albumin in synovial fluid decreased with no statistical significance. However, the concentration of matrix metalloproteinase-3 and its ratios to total protein and albumin did decrease significantly (P<0.05). Our results suggest that a larger controlled study is necessary to clarify the contributory effect of arthrocentesis and etodolac for patients with severe symptoms of TMJ disorders.

Matrix metalloproteinase-2 in synovial lavage fluid of patients with disorders of the temporomandibular joint

We examined the matrix metalloproteinase-2 (MMP-2) activity in synovial lavage fluid of patients with disorders of the temporomandibular joint (TMJ) and explored the possible correlationship between MMP-2 activity and radiological changes. We studied 86 patients and 10 healthy volunteers. An arthrogram and a double contrast arthrotomogram were taken to evaluate intra-articular morphological changes. The patients were divided into three groups: no abnormality (n = 36), internal derangement (n = 39), and osteoarthritis (n = 11). Samples of synovial fluid were studied by gelatin zymography, and we sought a correlation between the band detected and radiological findings. ProMMP-2 was detected in all samples and active MMP-2 was detected in 9/36 with no abnormality, 14/39 with internal derangement and 5/11 with osteoarthritis. No active form of MMP-2 was detected in the control group. The incidence of active MMP-2 was high in the internal derangement group and highest in the osteoarthritis group, which suggests that active MMP-2 plays an important part in the development of conditions of the TMJ.

Osteosarcoma metastatic to the mandible: a case report

A case of osteosarcoma that metastasized to the mandibular ramus from the femur in a 36-year-old man is presented. The patient was referred to us for the diagnosis and treatment of swelling of the left cheek. Radiologic examination showed a radiolucent lesion containing radiopaque areas within the left mandibular ramus. The patient previously suffered from a femoral small cell osteosarcoma, which was resected 71 months before our first examination. After induction of general anesthesia, a unilateral mandibulectomy and a simultaneous reconstruction using a titanium plate and an artificial condyle were performed. The postoperative course was uneventful, with satisfactory facial appearance and jaw function. The histopathologic features of the mandibular tumor were identical to those of the femoral tumor. Thus the mandibular lesion was diagnosed as a metastatic small cell osteosarcoma. At 27 months after the operation there had been no recurrence.

Inhibition of ileal Na+/bile acid cotransporter by S-8921 reduces serum cholesterol and prevents atherosclerosis in rabbits

The ileal Na+/bile acid cotransporter (IBAT) plays an important role in the enterohepatic circulation of bile acids. We investigated the effects of IBAT inhibition on the maintenance of serum cholesterol level by using a novel IBAT inhibitor, S-8921, in rabbits. Administration of S-8921 by its incorporation into the diet (0.01% to 0.1%) for 1 to 2 weeks in heterozygous Watanabe heritable hyperlipidemic rabbits decreased serum cholesterol by 29% to 37% and increased fecal excretion of measured bile acids by 60% to 180% compared with control rabbits. Liver microsomal cholesterol 7alpha-hydroxylase and 3-hydroxy-3-methylglutaryl coenzyme A reductase activities were increased by 75% to 84% and 84% to 89%, respectively, with S-8921 treatment. S-8921 administration (0.1% in the diet) to normal New Zealand White rabbits for 2 weeks resulted in increased hepatic low density lipoprotein receptor expression, which was assessed by Northern blot analysis. In cholesterol-fed New Zealand White rabbits, S-8921 treatment (0.003% to 0.1% in the diet) for 10 weeks dose-dependently inhibited the development of hypercholesterolemia. It also inhibited the accumulation of cholesterol in the aortic arch and reduced the severity of coronary atherosclerosis. These results indicate that IBAT inhibition by S-8921 affects serum cholesterol, liver enzymes, low density lipoprotein receptor activity, and atherosclerosis in the same manner as bile acid sequestrants. We suggest that an IBAT inhibitor such as S-8921 could be useful in the treatment of hypercholesterolemia.

Mechanism of hypocholesterolemic action of S-8921 in rats: S-8921 inhibits ileal bile acid absorption

The mechanism of the hypocholesterolemic action of S-8921, methyl 1-(3,4-dimethoxyphenyl)-3-(3-ethylvaleryl)- 4-hydroxy-6,7,8-trimethoxy-2-naphthoate, was examined in rats. In diet-induced hypercholesterolemic rats, 2 weeks oral administration of S-8921 dose- and time-dependently decreased plasma cholesterol level in the daily dose range of 0.1 to 10 mg/kg. Results with the dual-isotope plasma ratio method indicated that S-8921 inhibits cholesterol absorption from the intestine and enhances its elimination from the body. The in situ loop method showed that S-8921 does not inhibit the absorption of cholesterol from rat jejunum, clearly inhibits active absorption of taurocholic acid (TCA) and glycocholic acid (GCA) from rat ileum and does not inhibit passive absorption of cholic acid (CA) from the rat jejunum. In rat ileal brush-border membrane vesicles, S-8921 inhibited the sodium-dependent uptake of TCA in a concentration-dependent manner with IC50 of 2.1 microM, not the Na(+)-dependent D-glucose and L-alanine uptake. These results suggest that S-8921 is a potent, selective inhibitor of the Na(+)-dependent bile acid transport system in the ileal mucosal cell brush-border membrane, and this inhibition is the mechanism by which this drug decreases intestinal bile acid reabsorption to result in a significant decrease of plasma cholesterol.

Lysophosphatidylcholine promotes cholesterol efflux from mouse macrophage foam cells

We examined the effects of lysophosphatidylcholine (lyso-PC) on promoting cholesterol efflux from macrophage foam cells. Mouse peritoneal macrophages were converted to foam cells by incubation with [3H]cholesteryl linoleate-labeled or unlabeled acetyl-LDL. When these cells were incubated with lyso-PC, [3H]cholesterol release was promoted in relation to both dose and time, and cellular cholesterol mass was decreased, while medium cholesterol mass was increased. These cholesterol efflux-promotive effects of lyso-PC were confirmed by the fact that the lyso-PC-treated cells showed less oil red O staining than the control cells. ApoE secretion, estimated by Western blotting of the medium, was also augmented by lyso-PC. Both the cholesterol and apoE released by lyso-PC treatment were floated by ultracentrifugation of the medium after its density had been adjusted to 1.210 g/mL. By electron microscopic analysis, vesicular lipoproteins were observed in ultracentrifugally concentrated conditioned medium of lyso-PC. Monensin, a protein secretion inhibitor, effectively inhibited [3H]cholesterol release induced by lyso-PC but not by apoA-I. These results suggest that lyso-PC may inhibit the development of atherosclerosis or enhance its regression by stimulating cholesterol efflux from macrophage foam cells.

S-8921, an ileal Na+/bile acid cotransporter inhibitor decreases serum cholesterol in hamsters

The ileal Na+/bile acid cotransporter (IBAT) maintains the reabsorption of bile acids from the intestine in the enterohepatic circulation of bile acids. In the present study, we showed that S-8921 could dose-dependently inhibit the uptake of [3H] taurocholate in the COS7 cell line which constitutively expresses hamster IBAT. The IC50 value of S-8921 against 60 microM of [3H] taurocholate uptake was 66 +/- 8 microM and kinetic analysis revealed that the inhibition by 100 microM of S-8921 was a mixture of competitive and non-competitive types. In vivo administration of S-8921 by its incorporation into diet (0.001-0.1%) caused dose-dependent decrease of serum cholesterol concentrations accompanied by increased fecal excretion of bile acids in hamsters which were not loaded with cholesterol and bile acid. These data suggest that the inhibition of IBAT could decrease serum cholesterol in the non-cholesterol and -bile acid loaded normal condition.

Differential effect of benexate hydrochloride betadex on prostaglandin levels in stomach and inflammatory site in rats

We compared the effects of an anti-ulcer agent, benexate hydrochloride betadex (BHB), on prostaglandin (PG) levels in gastric tissue and inflammatory exudate in untreated and indomethacin-treated rats. BHB (100, 300 and 1000 mg/kg, p.o.) showed dose-dependent inhibition of gastric mucosal lesions induced by indomethacin (30 mg/kg, p.o.). Sustained decrease of PGs (PGE2 and 6-keto-PGF(1alpha)) in the gastric wall was observed from 0.5 to 6 hr after indomethacin treatment. BHB (300 and 1000 mg/kg) dose-dependently led to recovery of the indomethacin-induced decrease of gastric PGs at 1 and 6 hr after dosing. It did not antagonize the indomethacin-induced decrease of PG levels in the pleural exudate of carrageenin pleurisy nor did it affect the anti-inflammatory effects of indomethacin. BHB (100 to 1000 mg/kg) alone increased gastric PGE2 by 61% to 113%, while it decreased PGE2 levels in the pleural exudate by 9% to 71% at 6 hr after dosing. These results suggest that sustained increase of gastric PGE2 by BHB could be responsible for protection against indomethacin-induced gastric mucosal lesions and that BHB is a suitable anti-ulcer agent for NSAIDs without compromising their anti-inflammatory effects.

Depletion of brain glutathione by buthionine sulfoximine enhances cerebral ischemic injury in rats

Oxygen free radicals have been implicated in the pathogenesis of brain injury induced by ischemia/reperfusion. We studied the role of endogenous reduced glutathione (GSH) in brain infarction associated with focal cerebral ischemia caused by permanent ligation of the right middle cerebral artery (MCA) and the right common carotid artery (CCA) plus temporary occlusion of the left CCA. GSH levels in the ischemic side of cortex decreased with time after ischemia and preceded cortical infarction estimated by the staining of mitochondrial respiratory enzymes with 2,3,5-triphenyltetrazolium chloride. GSH levels in the contralateral cortex were unchanged through the experimental periods. The extent of decrease of GSH levels and the severity of infarction in the ischemic cortex at 24 h after ischemia depended on the duration of occlusion of the left CCA. Depletion of brain GSH with buthionine sulfoximine, a selective inhibitor for gamma-glutamylcysteine synthetase, exacerbated cortical infarction and edema after ischemia. These results suggest that the endogenous brain GSH is an important determinant in the defense mechanisms against lesion formation after ischemia and support the possible role of oxygen radicals in the pathogenesis of ischemic brain injury.

Attenuation of focal cerebral ischemic injury in transgenic mice overexpressing CuZn superoxide dismutase

Oxygen-derived free radicals have been implicated in the pathogenesis of vasogenic edema and infarction caused by ischemia and reperfusion injury. In earlier studies, exogenously supplied liposome-entrapped CuZn superoxide dismutase (CuZn-SOD) ameliorated ischemic brain edema and infarction in rats following focal cerebral ischemia. To ascertain directly the role of SOD in the protection against superoxide radical-induced injury, we measured infarct size and water content 24 hr following focal cerebral ischemia in nontransgenic mice and in transgenic mice bearing the human SOD1 gene. These transgenic mice have 3.1-fold higher cellular CuZn-SOD activity in the brain than do their nontransgenic littermates. We also measured antioxidant levels (reduced glutathione and reduced ascorbate) of contralateral cortex, infarct cortex, surrounding cortex, and striatum. Infarct size and brain edema were significantly decreased in transgenic mice compared with nontransgenic mice. Reduced glutathione and reduced ascorbate levels decreased in the ischemic hemisphere, but levels in surrounding cortex and striatum were significantly higher in transgenic mice than in nontransgenic mice. These results indicate that increased endogenous SOD activity in brain reduces the level of ischemic damage and support the concept that superoxide radicals play an important role in the pathogenesis of infarction and edema following focal cerebral ischemia.

Effect of antiperoxidative drugs on gastric damage induced by ethanol in rats

Lesion formation due to oral administration of absolute ethanol could be prevented by parenteral pretreatment with antiperoxidative drugs such as butylated hydroxytoluene (BHT), quercetin and quinacrine. Also effective were allopurinol and oxypurinol, inhibitors of xanthine oxidase, but not superoxide dismutase (SOD) and hydroxyl radical scavengers, such as sodium benzoate and dimethyl sulfoxide (DMSO). BHT, quercetin, quinacrine and sulfhydryl compounds such as reduced glutathione and cysteamine which offer gastroprotection in vivo against ethanol inhibited lipid peroxidation induced in vitro by ferrous ion in porcine gastric mucosal homogenate, but SOD, sodium benzoate, DMSO, allopurinol and oxypurinol did not. These results suggest the possibility that an active species, probably derived from free iron mobilized by the xanthine oxidase system, other than oxygen radicals such as hydroxyl radicals, contributes to lipid peroxidation and lesion formation in the gastric mucosa after absolute ethanol administration.

A possible mechanism of protection by polyamines against gastric damage induced by acidified ethanol in rats: polyamine protection may depend on its antiperoxidative properties

The protective mechanism of polyamines against acidified ethanol-induced gastric damage was studied. Their oral administration prevented the formation of gastric mucosal lesions induced by 90% ethanol in 150 mM HCl in a dose-dependent manner, with the order of the protective potency being spermine greater than spermidine greater than putrescine. The acidified ethanol-induced lesions were accompanied by a concomitant increase in gastric mucosal lipid peroxide levels, but spermine in a protective dose could prevent the increment of lipid peroxides. Polyamines, in a concentration-dependent fashion, inhibited the reduction of nitroblue tetrazolium by superoxide anion radicals generated in vitro in the xanthine-xanthine oxidase system and the lipid peroxidation in vitro induced by ferrous ion in the porcine gastric mucosal homogenate. The order of the superoxide scavenging potency and the inhibitory potency of iron-induced lipid peroxidation by polyamines corresponded to the order to the protective potency against acidified ethanol-induced gastric lesions. The present results suggest that cytoprotection by polyamines may be responsible for their antiperoxidative activities.

Lipid peroxidation: a possible role in gastric damage induced by ethanol in rats

Gastric mucosal lipid peroxide levels, based on the amounts of thiobarbituric acid reacting substances, increased soon after oral application of absolute ethanol. On the other hand, gastric mucosal nonprotein sulfhydryl levels slightly but significantly decreased. Administration of 20% ethanol, a mild irritant which can hardly produce gastric lesions, did not influence either level. Pretreatment with prostaglandin E2 or F2 alpha, in a dose that offered protection of the gastric mucosa, prevented the increase of mucosal lipid peroxides after absolute ethanol administration. These observations suggest that lipid peroxidation in the gastric mucosa may be closely related to production of the gastric damage by ethanol.

Gastric antral ulcers induced by a combination of acid, indomethacin and ischemia in rats

Gastric antral lesions were produced with hemorrhages by vascular ligation-induced ischemia in the prepyloric regions in rats. Additional treatments with intraluminal acid application and indomethacin markedly aggravated the lesions. Histological examination showed that the incidence of ulcers which penetrated the muscularis mucosae was nearly 100% upon treatment with a combination of acid, indomethacin and ischemia. This model provides a useful tool for studying gastric ulcer etiology.

Effect of polyamines on acidified ethanol-induced gastric lesions in rats

The participation of polyamines and nonprotein sulfhydryls in the gastric cytoprotective mechanisms was studied using gastric mucosal lesions produced by acidified ethanol in rats as an experimental model. Treatment with prostaglandin E2 (PGE2), but not cimetidine, prevented the formation of gastric mucosal lesions. Oral administration of cadaverine, spermidine and spermine prevented the lesion formation by acidified ethanol in a dose-dependent manner. Indomethacin or acetazolamide had no influence on the cytoprotective effect of spermine, whereas sulfhydryl blockers such as iodoacetamide and N-ethylmaleimide partially blocked it. Sulfhydryl compounds such as cysteine, reduced glutathione (GSH), and cysteamine prevented the lesion formation induced by acidified ethanol. The concentration of nonprotein sulfhydryls in the gastric mucosa was significantly decreased at 1 hr after administration of acidified ethanol, and this decrease was partially prevented by spermine or PGE2. These results suggest that the cytoprotective effect of spermine may not be mediated by endogenous prostaglandins or alkaline secretion in the gastric mucosa, but may be partially related to endogenous sulfhydryl compounds.

On RNA-polymerases of leukemia L 1210 origin and an enzymatic method to screen antitumor antibiotics

Four DNA-dependent RNA-polymerases were separated from the cell homogenate of moust leukemia L1210 cell by DEAE-cellulose column chromatography and tentatively designated as Peaks I, II, III and IV in the elution order. Peak II was inactivated by the addition of alpha-amanitin and effects of antibiotics and enzymes on the RNA-polymerase activity using Peaks, I, II and a mixture of Peaks I and II were examined. The RNA-polymerases were used to screen for enzyme inhibitors produced by microbes. This enzymatic method was successfully proved to select antitumor antibiotics.