Bufothionine induces autophagy in H22 hepatoma-bearing mice by inhibiting JAK2/STAT3 pathway, a possible anti-cancer mechanism of cinobufacini

ETHNOPHARMACOLOGICAL RELEVANCE

Cinobufacini is extracted from the skins and parotid venom glands of the toad for treating symptoms like swelling and pain in ancient times. Nowadays, cinobifucini injection has also achieved satisfactory therapeutic effects on hepatocellular carcinoma (HCC) in China.

AIM OF THE STUDY

Our previous work found that bufothionine, an alkaloid abundant in cinobufacini injection, induced mitochondria-mediated apoptosis. In this work, the underlying effects of bufothionine on autophagy in HCC and its possible dependent pathway were investigated.

METHODS

CCK-8 and Hoechst staining assays were performed to verify effects of drugs on proliferation and apoptosis of SMMC7721 cell. H₂₂-tumor-bearing mice model was established by inoculating ascites fluid. HE staining was used to observe pathological changes in liver and tumor tissues. ELISA and Western blot experiments were conducted to investigate IL-6/JAK2/STAT3 signaling pathway. The effects of drugs on expressions of autophagic relative proteins were investigated by Western blot in vitro and in vivo.

RESULTS

In vitro, CCK-8 and Hoechst staining assays showed that bufothionine inhibited SMMC7721 cell proliferation and promoted apoptosis at 100 μM. In vivo, bufothionine relieved symptoms of H₂₂-tumor-bearing mice and exerted anti-inflammation activity. ELISA and Western blot demonstrated that bufothionine significantly reduced serum IL-6 concentration, suppressed p-Stat3tyr705, p-Stat3ser727 and Jak2 expressions in tumor tissues and upregulated Atg5, Atg7 and LC3Ⅱ expressions in SMMC7721 cell and H₂₂ tumor.

CONCLUSION

This is the first report showing that bufothionine might induce autophagy in HCC by inhibiting JAK2/STAT3 pathway, presenting a possible anti-cancer mechanism of bufothionine in cinobufacini injection.

Zoonotic trypanosomes in South East Asia: Attempts to control Trypanosoma lewisi using veterinary drugs

A growing number of atypical human infections due to the livestock parasite Trypanosoma evansi, or to the rat parasite Trypanosoma lewisi, are reported in humans in Asia. In some cases, clinical evolutions request treatments, however, so far, there were very few attempts to control T. lewisi using trypanocidal drugs. In a study published elsewhere, the efficacy of human trypanocides is evaluated in laboratory rats, and it concludes that none of them is able to cure rats experimentally infected with T. lewisi. Control of T. lewisi in rat would be a step for identification of drugs against this parasite. In the present study, 4 veterinary drugs: diminazene aceturate, isometamidium chloride, melarsomine hydrochloride and quinapyramine sulfate and chloride, were evaluated at low and high doses, in intra-muscular injections to normal rats experimentally infected with a stock of T. lewisi from Thailand. None of these treatments being efficient, a trial was also made using melarsomine hydrochloride in T. evansi infected rats and in mixed T. lewisi and T. evansi infected rats, in order to demonstrate the efficacy of the drugs under the present protocol. T. evansi was cleared from the rat's blood the day after the treatment, while, T. lewisi remained unaffected until the end of the experiment. These observations clearly demonstrated the efficacy of melarsomine hydrochloride against T. evansi and its inefficacy against T. lewisi. In conclusion none of the veterinary drugs was efficient against this stock of T. lewisi. Other protocols using higher doses or other drugs and T. lewisi stocks should be investigated in further studies. The control of T. lewisi infection in Wistar rats, using veterinary trypanocidal drugs, remains so far unsuccessful.

Selective Inhibition of the Mitochondrial Permeability Transition Pore Protects against Neurodegeneration in Experimental Multiple Sclerosis

The mitochondrial permeability transition pore is a recognized drug target for neurodegenerative conditions such as multiple sclerosis and for ischemia-reperfusion injury in the brain and heart. The peptidylprolyl isomerase, cyclophilin D (CypD, PPIF), is a positive regulator of the pore, and genetic down-regulation or knock-out improves outcomes in disease models. Current inhibitors of peptidylprolyl isomerases show no selectivity between the tightly conserved cyclophilin paralogs and exhibit significant off-target effects, immunosuppression, and toxicity. We therefore designed and synthesized a new mitochondrially targeted CypD inhibitor, JW47, using a quinolinium cation tethered to cyclosporine. X-ray analysis was used to validate the design concept, and biological evaluation revealed selective cellular inhibition of CypD and the permeability transition pore with reduced cellular toxicity compared with cyclosporine. In an experimental autoimmune encephalomyelitis disease model of neurodegeneration in multiple sclerosis, JW47 demonstrated significant protection of axons and improved motor assessments with minimal immunosuppression. These findings suggest that selective CypD inhibition may represent a viable therapeutic strategy for MS and identify quinolinium as a mitochondrial targeting group for in vivo use.

Anti-tumour and pharmacokinetics study of 2-Formyl-8-hydroxy-quinolinium chloride as Galipea longiflora alkaloid analogue

The quinolinium chloride salt of 8-hydroxyqinolinecarbaldehyde (2-Formyl-8-hydroxy-quinolinium chloride) was prepared as Galipea longiflora alkaloid analogue and its anticancer activity was evaluated both in vitro and in vivo. This chloride salt was found to show certain degree of selectivity between hepatoma cells and normal hepatocytes in vitro. Athymic nude mice Hep3B xenograft model further demonstrated that this 2-Formyl-8-hydroxy-quinolinium chloride could execute strong anti-tumour activity with the identification of extensive necrotic feature from the tumour xenograft and limited adverse toxicological effect.

Quinpramine is a novel compound effective in ameliorating brain autoimmune disease

Acridine-iminodibenzyl chimeric compounds were previously introduced as a class of cholesterol-redistributing substances with antiprion effects. Here, we show that administration of the lead compound quinpramine to mice with experimental autoimmune encephalitis, an animal model of multiple sclerosis (MS), significantly ameliorates disease in preventive and therapeutic paradigms. Quinpramine treatment decreased the number of inflammatory CNS lesions, antigen-specific T-cell proliferation, and pro-inflammatory cytokines IFNgamma and IL-17. Quinpramine is thus an immunoregulatory drug that is a candidate pharmaceutical for MS.

Resistance to drug by different isolates Trypanosoma evansi in China

In order to understand drug resistance in Chinese Trypanosoma evansi isolates, the in vitro growth inhibition test was carried out to detect the sensitivities to suramin and antrycide of 12 T. evansi isolates. For suramin, 50% inhibitory concentrations (IC(50)) ranged from 0.041 to 0.752 microg/ml; for antrycide, the IC(50) values ranged from 0.00151 to 0.06694 microg/ml. In vivo experiments in mice with selected isolates showed that the isolate most resistant to suramin was not cured at a dosage of 10 mg/kg, while the isolate that was most resistant to antrycide showed only 50% cure rate at a dose rate of 5 mg/kg. The data presented here indicate that T. evansi isolates from China had differences in drug resistance, with some isolates exhibiting low sensitivity to suramin or antrycide, while a few isolates showed complete drug resistance to curative dosages of suramin or antrycide. No drug cross-resistance was observed between suramin and antrycide.

Beneficial effect of macrophage activating agent NK-4 on Thai HIV-infected patients

BACKGROUND

We examined the effect of NK-4 (4,4'-[3-[2-(1-ethyl-4(1H)-quinolinylidene) ethylidene] propenylene] bis(-ethylquinolinium iodide)) on the clinical course of Thai HIV-infected patients receiving antiretroviral drugs.

PATIENTS AND METHODS

Twelve subjects with CD4 count < 500/mm3 were enrolled to receive 0.5 mg of NK-4 orally once daily for 8 weeks and then twice daily during the follow-up.

RESULTS

Most patients showed vitality, increased appetite, stable body-weight, increased CD4 counts and no serious adverse effects due to viral load. We suggest that the increased CD4 counts are due to the macrophage activating effect of NK-4. The patients with increased CD4 counts showed lower alpha-N-acetylgalactosaminidase (alpha-NaGalase) activity than those with decreased CD4 counts.

CONCLUSION

These results suggest that the macrophage activating agent NK-4, as an inexpensive and safe drug for HIV-infected patients, may play a beneficial role in the clinical treatment of HIV-infected patients.

Antibody levels by indirect ELISA test in Trypanosoma evansi infected horses following treatment with quinapyramine sulphate

An ELISA test was used to determine the persistence of antibody levels in horses following treatment for Trypanosoma evansi. In 17 horses with T. evansi from two farms treated and cured with quinapyramine sulphate, ELISA antibody levels fell progressively post-treatment, but remained with positive results for 22.6 months in one horse, 12.8 months in a second, 4.1 months in another four and 2.3 months in three, whilst the rest became negative at 2.3 months. In two horses that suffered a post-treatment infection relapse the decrease in ELISA levels was only temporary, and a new increase in antibody levels was proven. The follow-up of these antibody levels could prove useful in clinical cases and in epidemiological studies, as well as for assessing the efficacy of drug treatment.

Activity of anticancer compounds against Trypanosoma cruzi-infected mice

Chagas' disease, which is caused by Trypanosoma cruzi, remains essentially incurable. Due principally to a lack of profit incentive, the pharmaceutical industry has had limited interest in developing new antichagasic drugs. Thus, a search for agents that exhibit activity against T. cruzi, although medicaments have been developed for the treatment of other diseases, seems justifiable. Responding to evidence that the principal biochemical differences between mammalian cells and African trypanosomes apply equally to T. cruzi, our evaluations were conducted. Previous work showed the effectiveness of anticancer agents against T. rhodesiense. In the present studies, 76 anticancer compounds were assessed for their ability to suppress the trypomastigotes of T. cruzi- infected mice. Five compounds were found to be active. The most effective was cycloheximide, which was more than six times as effective as the standard, nifurtimox.

The cure of acute Babesiasis perroncitoi in swine

From June to August in 1988, a total of 64 pure-bred Landrace, Yorkshire (large white) and Inner Mongolian Black Swine from a farm in Huhehot were affected with a disease, 13 died. The pathogen was confirmed primarily to be Babesia perroncitoi. The drugs used for treatment were Berenil and Acaprin. The intramuscular dose for Berenil was 3 mg per kilogram weight. The subcutaneous dose for Acaprin was 0.8 mg per kilogram weight. All of which had satisfactory results. In the same season in the second year and the third year, the disease was also reported, but all sick animals were cured.

A needle type therapeutic system incorporating laser light and lumin for immunotherapy of cancer growing in deep organs

Lumin is a potent cell-activating agent and a photosensitizer characterized by absorption peaks at 670 nm and 770 nm. It has already been demonstrated that macrophase activity is enhanced greatly by lumin administration with laser light irradiation and that this method is useful in cancer immunotherapy. In this study, a new needle type therapeutic system was developed for the immunotherapy of cancer growing in deep human organs. A human lung cancer grafted onto nude mice was strongly cicatrized by collagen fibres about four weeks after the first treatment. The collagen fibres seemed to seal-off the tumor and prevent its growth with intense cicatrization. In addition, a high T/B cell ratio of lymphocytes was observed in the peripheral blood of the treated mice, although the thymus is congenitally absent from nude mice. These results demonstrated that the system is a reliable method for cancer treatment in deep organs without side effects and/or major surgical intervention.

Platelet activating factor inhibition reduces lung injury after cardiopulmonary bypass

Because cardiopulmonary bypass (CPB) produces a diffuse inflammatory reaction that may injure multiple organs and complicate cardiac surgical procedures, we examined the use of a competitive inhibitor of platelet activating factor (SDZ HUL-412) in a porcine model of CPB as a means to ameliorate pulmonary injury after CPB. Thirteen pigs (35 to 40 kg) underwent CPB at 28 degrees C for 2 hours, followed by 2 hours of observation. Group I (n = 6) received SDZ HUL-412 (a quinolinium compound) intravenously (3 mg/kg loading dose and 2 mg.kg-1.h-1 continuous infusion) starting before sternotomy. Group II (n = 7) received a saline vehicle. Peak airway pressure, pulmonary arterial pressure, left atrial pressure, and arterial blood gases were measured and flow cytometry evaluated surface expression of adhesion molecule subunit CD18 on circulating neutrophils. Pulmonary function was significantly improved in group I. Fifteen minutes after CPB, dynamic lung compliance in group I was 91% +/- 12% of baseline versus 49% +/- 5.2% in group II (p = 0.06 by analysis of variance). After CPB, the arterial oxygen pressure was also significantly better in group I than in group II (425 +/- 61 versus 234 +/- 76 mm Hg) (p < 0.05). The rise in pulmonary vascular resistance after CPB was less in group I (p < 0.05) (323 +/- 55 to 553 +/- 106 dynes.s.cm-5) than in group II (531 +/- 177 to 884 +/- 419 dynes.s.cm-5) at the end of the observation period. CD18 up-regulation increased similarly in the two groups during CPB.(ABSTRACT TRUNCATED AT 250 WORDS)

Trypanosoma evansi infection in dogs: seasonal prevalence and chemotherapy

A 1-year survey was undertaken to determine the incidence of Trypanosoma evansi in dogs at Ludhiana, India. Of 64 dogs examined by wet film, thin smear, thick smear and mouse inoculation, three (4.68%) were found to be positive for T. evansi. All the positive animals were detected during the rainy and post-rainy seasons. The treatment of three infected dogs with a combination of quinpyramine sulphate and chloride (3:2 w/w) resulted in complete recovery of two dogs; another dog died on the day therapy was initiated.

A comparison of the antigen detection ELISA and parasite detection for diagnosis of Trypanosoma evansi infections in camels

Two herds of 60 camels each, living in Trypanosoma evansi endemic areas, were selected and studied for a period of 18 months. Animals in one herd were treated prophylactically with quinapyramine prosalt (May and Baker, Dagenham, UK), while those in the other herd were treated individually with quinapyramine dimethylsulphate (May and Baker, Dagenham, UK) when proven parasitaemic. The herd on prophylaxis was sampled for antigen and patent infection monthly. The other herd was sampled weekly for patent infection and fortnightly for antigen. The results obtained could be divided into four categories. The first category comprised cases (52 out of 61) in which the presence of trypanosome antigens could be correlated with parasitological diagnosis. In 80% of these animals the antigens disappeared from the circulation within a period of 30 days following chemotherapy. The second category comprised those animals with parasitologically proven infections but which did not have antigens in their sera. This was observed in nine camels, seven of which were from the herd that was being examined weekly for the presence of trypanosomes. These were considered to be animals in early infection, as the subsequent sera were also negative for anti-trypanosome antibodies and immune complexes. The third category comprised camels which were antigen-positive but aparasitaemic. Sera from these animals were also positive for anti-trypanosome antibodies, indicating that antigen-positivity was a true reflection of trypanosome infections in these animals. The last category comprised pre-weaned camel calves which appeared to have some form of protection against trypanosomiasis, as evidenced by the absence of trypanosomes, antigens and antibodies throughout the early period of their lives. Only occasional antigenaemia was found in a few calves. It is concluded that trypanosome antigen detection may give a more accurate idea of the prevalence of T. evansi infections than does whole parasite detection.

Derivation and characterization of a quinapyramine-resistant clone of Trypanosoma congolense

Over a period of 208 days a quinapyramine-resistant population was derived in vivo from a quinapyramine-susceptible clone of Trypanosoma congolense: IL 1180. While the dose of quinapyramine sulfate required to cure 50% of mice infected with the parental clone was 0.23 mg/kg of body weight, the 50% curative dose for the resistant derivative, IL 1180/Stabilate 12, was greater than 9.6 mg/kg. This approximately 40-fold increase in resistance to quinapyramine was shown to be associated with an 8-fold increase in resistance to isometamidium, a 28-fold increase in resistance to homidium, and a 5.5-fold increase in resistance to diminazene. Cross-resistance to homidium and diminazene was also demonstrated in goats. Two clones derived from the drug-resistant derivative underwent cyclical development in Glossina morsitans centralis, producing mature infection rates of 39.6 and 23.9%. Thus, induction of resistance to quinapyramine in T. congolense IL 1180 was associated with cross-resistance to isometamidium, homidium, and diminazene and did not compromise the population's ability to undergo full cyclical development in tsetse flies.

Administration of a receptor antagonist for platelet-activating factor during equine endotoxaemia

Platelet-activating factor (PAF) is an important mediator of endotoxaemia and various PAF receptor antagonists prevent many of the adverse effects of experimental endotoxaemia in laboratory animals. In this study a specific PAF receptor antagonist was used to investigate the role of PAF in equine endotoxaemia. At an interval of not greater than 10 days, 6 horses were each challenged with endotoxin and endotoxin with concurrent administration of SRI 63-441, a PAF receptor antagonist. The order of the treatments was randomised. Clinical signs, serum biochemical and coagulation profiles, and platelet aggregation in vitro were monitored in all horses for 24 h after treatment. Challenge with endotoxin increased maximal platelet aggregation induced by PAF. This response was blocked by administration of SRI 63-441 concurrently with endotoxin. No changes in percentage maximal platelet aggregation to ADP or collagen were noted after administration of endotoxin. The PAF receptor antagonist delayed the onset of fever, tachycardia, leucopenia and lactic acidaemia. Lack of more profound beneficial alterations of the horses' responses to endotoxin may have been due to the low dose of endotoxin administered in this model or to only partial effectiveness of SRI 63-441 in blocking the effects of endotoxin-induced PAF.

Trypanosomal antigen and antibody levels in field camels following treatment with two trypanocidal drugs

The efficacy of treatment in 61 naturally trypanosome-infected camels was evaluated by antigen and antibody detection. Following treatment of 14 infected field camels with an arsenical drug (RM110) no trypanosomal antigens could be detected in the animals which were treated with 0.6 mg/kg body weight and 1.2 mg/kg body weight, 90 days thereafter. In two out of three camels treated with 0.4 mg/kg body weight no trypanosomal antigens could be detected by day 90 post-treatment. However, there was evidence of trypanosomal antigens in camels treated with 0.2 mg/kg body weight and untreated positive controls. Antibody levels were still high in all the 14 camels, 90 days post-treatment. In another group of 55 field camels, of which 47 camels were parasite-positive and eight parasite-negative, trypanosomal antigens could not be detected in 42 camels, 28 and 48 days post-treatment with Quinapyramine Prosalt. However, antigen levels were still high in five parasite-positive camels, 48 days post-treatment. In all the parasite-positive camels, antibody levels were still high 48 days after treatment. In the eight parasite-negative camels, antigens were detected in four camels before treatment. By day 48 post-treatment, all the four camels were antigen-negative. However, four of the eight parasite-negative camels were still antibody-positive by day 48 post-treatment. These observations indicated that antigen-detection could be used to evaluate the success of therapeutic trials where trypanosome detection tests may fail to pick low patent infections.

In vivo assays for drug resistance in Babesia divergens using the Mongolian gerbil, Meriones unguiculatus

Two in vivo drug resistance assays were developed using gerbils. Cross resistance, involving related babesicides as well as the chemically unrelated antibiotic, oxytetracycline, was demonstrated, but the suggestion that imidocarb may select for pathogenic strains of parasites was not supported. Limited tests of field strains did not detect resistance. It is suggested that an in vitro assay would be more appropriate for surveys through in vivo assays would be essential for confirmatory studies.

Hypoxia, PAF, and necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is an important neonatal disease with a high mortality rate. The pathophysiology is unclear but epidemiologic studies suggest that hypoxia and infection are important risk factors. In this review we discuss the effect of hypoxia and platelet-activating factor (PAF) on intestinal blood flow and intestinal necrosis, and implicate PAF as an important mediator in hypoxia-induced intestinal injury. Finally we provide evidence that PAF may be important in neonatal NEC.

In vivo and in vitro sensitivity of Trypanosoma evansi and T. equiperdum to diminazene, suramin, MelCy, quinapyramine and isometamidium

The sensitivity of three Trypanosoma equiperdum clones and thirteen Trypanosoma evansi clones originating from the People's Republic of China, the Philippines, Ethiopia and elsewhere to a series of drugs was determined in vivo and in vitro. The drugs tested were diminazene aceturate (Berenil), suramin (Naganol), MelCy (Cymelarsan), quinapyramine sulfate (Trypacide) and isometamidium chloride (Samorin). The activity of each drug was expressed as: 1) in vitro: the minimal effective concentration which killed trypanosome population by 100% within 24 h of drug exposure (MEC100); the maximum tolerated concentration in which trypanosomes could propagate at the same rate as the controls during 48 h of drug exposure (MTC100); 2) in vivo: the curative dosage in 100% of infected mice (CD100); the highest ineffective dosage: 100% of infected mice remain infected (ID100). MEC100 values of diminazene aceturate ranged from 0.0556 microgram/ml to 14.24 micrograms/ml for the eleven tested clones (differed by 256-fold); CD100 values of this drug ranged from 2.25 mg/kg to greater than 89 mg/kg (differed by greater than 40-fold). Diminazene aceturate at up to 89 mg/kg had no effect on T. evansi SHBR, T. equiperdum PBR (Berenil resistant organisms selected by continual passage of the organisms through mice treated with increasing concentrations of drug), or T. evansi AH (strain isolated in the field). Comparable MEC100 values for other trypanocides tested were 1-8 micrograms/ml for suramin, 0.005-0.04 microgram/ml for MelCy, 1-16 micrograms/ml for quinapyramine sulfate and 1-4 micrograms/ml for isometamidium chloride. Clones selected for resistance to diminazene aceturate were not cross-resistant to suramin and isometamidium chloride. In contrast, the clones resistant to diminazene were shown to be more sensitive to quinapyramine sulfate than the normal strains in in vivo tests. The results indicate that resistance to diminazene aceturate by T. evansi and T. equiperdum clones in vivo also occurred in vitro. Resistance to isometamidium chloride in the clones tested in vivo was not observed in vitro, except for T. equiperdum SA. It therefore appears that drug bioavailability is altered or drug biotransformation occurs during the in vivo test. We conclude that the in vitro assay procedure may be of potential use for screening new trypanocides and also for the rapid detection of drug resistant isolates of T. evansi and T. equiperdum.

Lipid mediators of tumor necrosis factor-alpha-induced uveitis

The authors tested the hypothesis that platelet-activating factor (PAF) and cyclooxygenase metabolites of arachidonic acid mediate the ocular inflammatory response to intravitreally injected tumor necrosis factor-alpha (TNF alpha). Rabbits were treated with the PAF receptor antagonist SRI 63-441, the cyclooxygenase inhibitors indomethacin and naproxen, or SRI 63-441 and indomethacin. At 24 hr after intravitreal injection of TNF (20,000 U), the severity of inflammation was assessed based on iridal hypermia, aqueous humor leukocyte number and aqueous humor protein, immunoreactive-prostaglandin E (I-PGE), and leukotriene B4 (LTB4) concentrations. Although all of the treatments significantly reduced the severity of anterior uveitis, SRI 63-441 plus indomethacin was the most effective, indomethacin and naproxen were intermediately effective, and SRI 63-441 was the least effective. The results of this study are consistent with an important role for cyclooxygenase metabolites of arachidonic acid in the inflammatory response to TNF alpha, particularly with respect to dilation of iridal blood vessels. Although naproxen was nearly as effective as indomethacin in reducing aqueous humor I-PGE levels, indomethacin conferred significantly more protection to the blood-aqueous barrier as shown by lower protein levels in the aqueous humor. Thus, although cyclooxygenase inhibition may partially explain the protection afforded the blood-aqueous barrier by these nonsteroidal anti-inflammatory agents, the data suggest that indomethacin may also exert anti-inflammatory effects that are independent of cyclooxygenase inhibition. Furthermore, the data are consistent with TNF alpha releasing PAF in the eye and PAF acting both directly, by increasing vascular permeability, and indirectly, by promoting release of cyclooxygenase and lipoxygenase metabolites of arachidonic acid.

The effects of PAF antagonists on arrhythmias and platelets during acute myocardial ischaemia and reperfusion

The aim of the study was to examine a possible role for platelet activating factor (PAF) in experimental myocardial ischaemia and reperfusion. Anaesthetized open-chest greyhounds were subjected to 40 min of coronary artery (LAD) occlusion followed by reperfusion. Blood samples for platelet counting were obtained from a local coronary vein draining the ischaemic region. Pretreatment with PAF antagonists BN52021 (5 mg kg-1 i.v.) or SRI63441 (10 mg kg-1 i.v.), 15 min prior to occlusion reduced the ventricular ectopic count during the ischaemic period from 614 +/- 82 (controls) to 296 +/- 145 (BN52021) and 474 +/- 200 (SRI63441). Both drugs also reduced the incidence of ventricular fibrillation (VF) (during ischaemia and reperfusion) from 90% (controls), to 50% (BN52021) and 43% (SRI63441). Ischaemia was accompanied by a 32 +/- 7% reduction in coronary venous platelets; this was attenuated by both BN52021 (-2 +/- 6%) and SRI63441) (-1 +/- 5%). These results suggest that PAF may contribute to ischaemia and reperfusion-induced arrhythmias by activating platelets.

Pharmacologic modulation of experimental postischemic hepatic function

The present study evaluated and compared the effects of SRI 63-441, a potent platelet activating factor antagonist, superoxide dismutase (SOD), an oxygen free radical scavenger, and ibuprofen, a cyclooxygenase inhibitor on hepatic function after 90 minutes of warm ischemia. After warm ischemia, livers were harvested and underwent 90 minutes of warm, oxygenated, sanguinous perfusion on an isolated liver perfusion apparatus. Pretreatment of donor animals with 20 mg/kg intravenous (I.V.) SRI 63-441 5 minutes before induction of total hepatic ischemia resulted in significantly increased bile production, a significant decrease in transaminase release, and a higher tissue adenosine triphosphate (ATP) content when compared with ischemic nontreated controls. SOD resulted in improved bile production and decreased transaminase liberation only when present in the perfusate at the time of in vitro reperfusion. Ibuprofen did not improve postischemic hepatic function in this model. Electron microscopy revealed patchy hepatocellular vacuolization with an intact sinusoidal endothelium in all ischemic livers. However, the degree of damage was less severe in the livers from those rats pretreated with 20 mg/kg SRI 63-441. This study demonstrates that SRI 63-441 pretreatment significantly reduces hepatic warm ischemic injury, and in the present model, appears superior to two other agents that have been advanced in the treatment of ischemic injury. The use of such agents singly or in combinations have important implications as regards gaining a better understanding of the basic mechanisms in organ ischemia, and moreover, for therapeutic applications in organ ischemia and preservation.

Effects of combined receptor antagonists of leukotriene D4 (LTD4) and platelet-activating factor (PAF) on rhesus airway responses to LTD4, PAF and antigen

Rhesus monkeys with IgE-mediated asthmatic-type responses to Ascaris suum antigen were pretreated with a combination of 2 receptor antagonists to leukotriene D4 (LTD4) and platelet-activating factor (PAF). This combination of anti-LTD4 and anti-PAF was shown to inhibit airway responses to either LTD4 or PAF in separate experiments in these Ascaris airway-reactive animals. When the same combination of LTD4 and PAF receptor antagonists was used to pretreat the same animal prior to aerosol challenge with Ascaris antigen we could not demonstrate inhibition of the antigen-induced airway response. Thus, combined receptor blockade for LTD4 and PAF did not alter IgE-mediated acute airway responses to antigen in this species. We review the current status of rhesus asthma and LTD4 and PAF receptor antagonist activity in this model.

Dequalinium, a topical antimicrobial agent, displays anticarcinoma activity based on selective mitochondrial accumulation

Positively charged lipophilic compounds, such as rhodamine 123, localize in mitochondria and are selectively accumulated and retained by carcinoma cells. It has been suggested that this phenotype may be exploited for selective killing of carcinoma cells by lipophilic cations. Here we report that doubly positively charged dequalinium, which has been used for 30 years as an antimicrobial agent in over-the-counter mouthwashes, lozenges, ointments, and paints, exhibits significant anticarcinoma activity. Dequalinium is more effective than seven of eight established anticancer drugs in prolonging the survival of mice with intraperitoneally implanted mouse bladder carcinoma MB49. Dequalinium also inhibits the growth of subcutaneously implanted human colon carcinoma CX-1 in nude mice and recurrent rat colon carcinoma W163 in rats. Lipophilic cationic compounds, such as dequalinium, could comprise a unique class of anticarcinoma agents.

Elimination of the gametocytes of Theileria annulata of cattle by primaquin phosphate

Calves were experimentally infected with Theileria annulata and five drugs were administered in an attempt to exterminate the gametocytes of the parasite. The results of the experiment proved that primaquin phosphate is an effective parasiticide. The gametocytes from 30 calves treated with primaquin phosphate were exterminated completely. A further eight calves were treated with sulfamethoxypyrazine, trimethoprim, naganin and acaprin, but these drugs were not found to be effective in eliminating the gametocytes. The phase, size and colour of the gametocytes in these calves were the same as those of the four untreated control calves.

[Immunopharmacological actions of lumin (II): Effect of lumin administration in NZB X NZW (B/W) F1 mice]

Lumin was administered at doses of 0.1 to 100 micrograms/kg for 5 months to NZB/W F1 mice as the model animal for studying systemic lupus erythematosus (SLE), a human autoimmune disease. The increase in anti-thymic autoantibody level was significantly inhibited at doses of 1 to 100 micrograms/kg. Also, the induction of suppressor T cells by concanavalin A was significantly promoted. In addition, recovery activity was significantly observed, over-coming the reduction in plaque-forming cell (PFC) response of anti-sheep erythrocytes at a dose of 100 micrograms/kg, as well as the reduction in PFC response of anti-trinitrophenylated-lipopolysaccharide at doses of 0.1 to 100 micrograms/kg. The above results prove that lumin exhibits an immunomodulating effect against immune disease in mice.

Inhibition of rat colon tumor isograft growth with dequalinium chloride

In searching for a new approach to the systemic treatment of colorectal carcinoma, we have observed that certain lipophilic cationic compounds are accumulated and retained for a significantly longer period in the mitochondria of living carcinoma cells than in normal cells or sarcoma cells. We report the in vivo therapeutic effect of one of these compounds, dequalinium chloride, on the W163 rat colon carcinoma isograft, which grows rapidly in Wistar/Furth rats after primary tumor implantation, and which recurs rapidly after primary tumor resection. In the primary transplant model, tumors were implanted, and daily dequalinium chloride treatments were begun the following day in doses ranging from 1 to 10 mg/kg. In the recurrence model, isografts were implanted, allowed to grow for one week, and then all gross tumor was resected. Dequalinium chloride was administered in varying daily doses starting the day after resection. In both models, tumor was removed on day 11 after implantation or resection. At sublethal doses, dequalinium chloride significantly inhibited primary tumor growth to 60% that of controls and recurrent tumor growth to 50% that of controls. We propose that this unique biologic approach of targeting carcinoma mitochondria with lipophilic cationic compounds may provide a major new opportunity for treating colorectal carcinoma.

Comparative study of the configuration and the cleanliness level of root canals prepared with the aid of sodium hypochlorite and bis-dequalinium-acetate solutions

Bis-dequalinium acetate (BDA), a quaternary ammonium compound, was introduced as a bactericidal and chemotherapeutic agent for endodontic use. This study was undertaken to compare the efficacy of this compound to 5.25% sodium hypochlorite in the cleansing and shaping of root canals. One hundred twenty freshly extracted teeth were divided into three groups. Each group was treated with the aid of the test material; saline solution was used as a control. After completion of the endodontic preparation, a silicone imprint of the canals was performed and the teeth were decalcified. The imprints were examined three-dimensionally to determine the amount of debris and canal configuration due to defective preparation and anatomic variation. No significant difference could be observed between the tested materials with respect to cleanliness and the shape of the canals. At the apical third, however, the BDA-treated canals showed more favorable results with respect to cleanliness. On the basis of the present and previous findings, it was concluded that BDA might be a favorable replacement for sodium hypochlorite as an irrigation solution.

[Cellular mechanism of the antileukemic action of quinoline dibromide]

Autoradiography (3H-thymidine) and DNA-cytofluorometry were used to study the effect of quinoline dibromide (QD), a potential inhibitor of cobalamine-dependent methionine synthetase, on the kinetics of cell proliferation of L-1210 mouse leukemia. QD was found to produce the secondary blockade of leukemic cells in the late S-phase of the mitotic cycle. Such a mechanism of QD action promoted the potentiation of antitumor activity of the antimetabolites methotrexate, cytosine arabinoside and 5-fluorouracil during combined chemotherapy.

Chemotherapy of Babesia divergens in the gerbil, Meriones unguiculatus

It was found that surprisingly low doses of four babesicides were effective against Babesia divergens in gerbils and it was concluded that this was due to the involvement of host resistance, which may be of a non-specific nature. The efficacy of the drugs relative to each other was the same in gerbils as in cattle and this host-parasite system is evidently more suitable for the screening of babesicides than are other rodent babesia systems. The prophylactic dose of imidocarb dipropionate required to provide a similar degree of protection in gerbils as in cattle was found to be much higher and was very close to toxic levels. Challenge infections resulted in sterile immunity. Acute babesiosis in gerbils could be cured with all four drugs if parasitaemias were below approximately 45 per cent and packed cell volumes above 18 per cent at treatment.

Assessment of prevalence of clinical babesiosis in cattle in Northern Ireland

Information on the number of clinical cases of bovine babesiosis in Northern Ireland was gathered from three sources: (a) a representative sample of farms; (b) all veterinary practices normally attending cattle; (c) the drug companies which produce babesicide. From (a) an estimate of 4520 clinical cases per year was derived, from (b) 3923 and from (c) 5600. A resultant estimate of at least 4000 cases per year was assumed to be reasonable. The mortality rate overall was 17.4 per cent but ranged from 8.8 per cent to 100 per cent on one farm. A final estimate of 12.5 per cent mortality was assumed resulting in an annual number of 500 deaths. Costs for mortality were estimated for each type of animal involved and figure of pounds 203,500 per year attributed. When the costs of treatment, assessed at pounds 31,000 per annum, unquantified production losses and increased labour costs were added an annual figure of pounds 250,000 per annum was estimated. This cost mainly falls to farmers in the three counties of Armagh, Fermanagh and Tyrone where 84 per cent of clinical cases take place. As a result the farmers in that area have to bear a loss of pounds 212,500 per year because of babesiosis.

Chemotherapy of Babesia felis infection: efficacy of certain drugs

The efficacy of 10 drugs was tested against Babesia felis infection in domestic cats. Primaquine phosphate administered per os or as an intramuscular injection was found to be highly effective and the obvious drug of choice when compared with conventional babesicides. The recommended dosage is 0,5 mg/kg body mass of primaquine base. Repeated treatments are well tolerated but single doses in excess of 1 mg/kg are known to cause mortality in cats.

Quinuronium sulphate for the treatment of Babesia divergens infections of splenectomised calves

Quinuronium sulphate was inoculated into splenectomised calves at various times in relation to artificial infection of the calves with Babesia divergens. When the drug was given one day before the parasites it had no effect on the course of the infection. However, when it was given at the time of onset of fever or haemoglobinuria, development of the infection was arrested. Two weeks after therapy, recrudescences of parasites invariably occurred. In the case of animals treated at onset of fever these recrudescences were accompanied by increasing anaemia. Treated animals resisted subsequent challenge but remained as carriers of the parasite.

The use of dequalinium acetate as a disinfectant and chemotherapeutic agent in endodontics

Dequalinium compounds are known as chemotherapeutic and bactericidal agents. They are used in various areas of medicine and oral medicine for combating cases of mixed infections. Until now, results of basic research studies have been published whose objective was to examine the suitability of dequalinium preparations as cleansing agents and intracanal dressings for endodontic use. This article presents for the first time a number of selected cases from a clinical research study in which widespread periapical lesions revealed before the start of treatment were treated with a preparation whose active ingredient was dequalinium acetate. The results of treatment and follow-up are given. These case reports show that healing of the periapical lesions occurs relatively quickly and is generally completed within a period of 9 months.

Antileukemic activity of 2-bis(2-methylthio)vinyl-1-methylquinolinium iodides

Reaction of 1-methylquinolinium-2-dithioacetic acid zwitterions with excess methyl iodide in dimethylformamide gave the corresponding bis(2-methylthio)vinyl derivatives. These compounds were more soluble in both aqueous and organic media than the dithioacetic acid zwitterions but showed comparable antileukemic activity in mice. Reaction with morpholine converted a bis(2-methylthio)vinyl derivative almost quantitatively to the 2-mono(methylthio)-2-morpholino derivative. Leukemia cell culture studies of the 6-methyl derivative showed no effect on cell cycle processes.