Trypanosoma brucei: trypanocidal effect of salicylhydroxamic acid plus glycerol in infected rats.

Rats inoculated with Trypanosoma brucei brucei EATRO 427 and having a high degree of parasitemia were treated with a series of intra-peritoneal injections of Salicylhydroxamic acid (SHAM) plus glycerol. Permanent cures were obtained with 380 mg/kg SHAM plus 3.8 g/kg glycerol, a dosage regime which was just sublethal. Using a regime with which permanent cure was obtained, the SHAM concentration in the blood plasma remained above 2 mmole/liter for about 20 min, while the glycerol concentration remained above 22 mmole/liter for about 1 hr. The brain concentration of SHAM was close to the plasma concentration. The concentration of glycerol in the brain remained far below the plasma concentration, reaching 6 to 8 mmole/liter between 1 and 2 hr after the beginning of treatment. Treatment with glycerol did not affect the mobility of the trypanosomes nor the survival of infected rats after treatment with suramin.     

Toxoplasma gondii: in vitro and in vivo activities of the hydroxynaphthoquinone 2-hydroxy-3-(1'-propen-3-phenyl)-1,4-naphthoquinone alone or combined with sulfadiazine

The compound 2-hydroxy-3-(1'-propen-3-phenyl)-1,4-naphthoquinone (PHNQ6) was evaluated for activity against Toxoplasma gondii, alone or combined with sulfadiazine. Treatment with PHNQ6 combined with sulfadiazine protected at least 70 and 90% of mice infected with RH and EGS strains, respectively. Mice were treated with PHNQ6 (50 mg/kg/day) alone or combined with sulfadiazine (40 mg/L) 30 days after infection with P strain. The number of brain cysts was lower in mice treated with PHNQ6 alone or combined with sulfadiazine compared to that in control mice. Degenerated bradyzoites were observed in animals treated with PHNQ6. Infectivity of bradyzoites treated with PHNQ6 alone or combined with sulfadiazine was inhibited after in vitro incubation.     

Double-Blind, Multicenter Evaluation of Lansoprazole and Amoxicillin Dual Therapy for the Cure of Helicobacter pylori Infection

Background Treatment with amoxicillin plus omeprazole results in disappointing cure rates of Helicobacter pylori infection. The minimal inhibitory concentration of lansoprazole for H. pylori in vitro is lower than that for omeprazole, prompting interest in treatment with amoxicillin plus lansoprazole.
Materials and Methods. H. pylori -infected patients with endoscopically documented duodenal ulcer either currently or within the past year were randomized to 14 days of (1) lansoprazole, 30 mg bid, plus amoxicillin, 1 gm tid; (2) lansoprazole, 30 mg tid, plus amoxicillin, 1 gm tid; (3) lansoprazole, 30 mg tid alone; or (4) amoxicillin, 1 gm tid alone. Endoscopy was done at enrollment and at 4 to 6 weeks after completion of treatment or for recurrent symptoms. H. pylori status was assessed by culture and histology. Ulcer prevalence was evaluated at follow-up endoscopy.
Results. Two hundred sixty-two patients met enrollment criteria and were treated. By per-protocol analysis, H. pylori infection was cured in 57% of those treated with lansoprazole twice daily plus amoxicillin and in 67% of those treated with lansoprazole three times daily plus amoxicillin, compared with 0% treated with lansoprazole alone or amoxicillin alone ( p < .001 for dual therapy versus either monotherapy). Amoxicillin resistance was not observed. At follow-up endoscopy, ulcer prevalence was 17% in patients treated with lansoprazole twice daily plus amoxicillin, 23% in those treated with lansoprazole three times daily plus amoxicillin, 33% in those treated with lansoprazole alone, and 35% in those treated with amoxicillin alone ( p = .024; lansoprazole twice daily plus amoxicillin versus amoxicillin alone).
Conclusions. Treatment with amoxicillin plus lansoprazole, 30 mg tid, led to cure of H. pylori infection in 67% of patients with active or recently healed duodenal ulcer.     

Buprenorphine does not affect acute murine toxoplasmosis and is recommended as an analgesic in Toxoplasma gondii studies in mice

Groups of mice were infected with tachyzoites of the RH strain of Toxoplasma gondii, treated with the opioid analgesic buprenorphine, sodium sulfadiazine, a combination of buprenorphine and sodium sulfadiazine, or nothing in the drinking water, on days -1 to 12 postinfection. Mice in the T. gondii-infected buprenorphine-treated group did not live significantly longer (P > 0.05) than mice given T. gondii and not treated with buprenorphine. Clinical observations of mice indicated that buprenorphine treatment reduced distress and pain in mice with acute toxoplasmosis. Mice treated with sodium sulfadiazine alone or sodium sulfadiazine combined with buprenorphine survived the 28-day study. Mice treated with buprenorphine and not infected with T. gondii also survived the 28 days. This study demonstrates that buprenorphine does not adversely interfere with acute T. gondii infection and indicates that buprenorphine can be given to mice to alleviate pain and distress associated with a T. gondii infection, and not adversely influence the results of toxoplasmosis studies. Analgesic (buprenorphine) treatment should now be the standard of care for mice in acute toxoplasmosis studies.     

Effect of pyrimethamine and sulfadiazine on the fine structure and multiplication of Toxoplasma gondii in cell cultures.

Rhesus monkey kidney cell cultures were inoculated with Toxoplasma gondii organisms obtained from peritoneal fluid of mice infected with the RH strain. Pyrimethamine and sulfadiazine were added either singly or in combination to the cultures 4 hr after inoculation. Twenty-four hours later the effect of the drugs on the parasites were studied by light and electron microscopy. Pyrimethamine (1.0 mug/ml) inhibited multiplication of the parasites and caused striking morphological changes. Organisms were rounded and often had a fragmented nucleus. Division was inhibited as indicated by abnormal daughter membrane formation during endodyogeny. No effect was evident in sulfadiazine-treated parasites when concentrations up to 50 mug/ml were used. However, combination of ineffective levels of pyrimethamine (0.1 mug/ml) and sulfadiazine (0.5 mug/ml) produced effects similar to those seen at a higher concentration of pyrimethamine indicating a synergistic action of the 2 drugs.     

Effects of sulfadiazine and amprolium on Neospora caninum (Protozoa: Apicomplexa) infections in mice

An immunosuppressed mouse model was used to determine the effects of amprolium and sulfadiazine on experimental Neospora caninum infections. Both drugs were given in the drinking water. Neither drug was effective in treating infections when given 7 days after inoculation of tachyzoites, when clinical signs of disease had developed. Amprolium did not prevent deaths or development of clinical signs when given in the drinking water at 1 mg/ml or 5 mg/ml 3 days after inoculation of tachyzoites. Sulfadiazine in drinking water was not effective when given at 0.5 mg/ml but was effective in preventing deaths and clinical disease when given at 1 mg/ml 3 days after inoculation with tachyzoites. Most mice (6 of 10) treated for 3 days with 1 mg/ml sulfadiazine in drinking water developed encephalitis after drug treatment was stopped. Treatment for 14 days with 1 mg/ml sulfadiazine in drinking water was needed to protect 90% of inoculated mice.     

Efficacy of atovaquone and sulfadiazine in the treatment of mice infected with Toxoplasma gondii strains isolated in Brazil

The efficacy of atovaquone and sulfadiazine was examined alone or in combination for the treatment of mice infected with six Brazilian Toxoplasma gondii strains previously genotyped using the PCR-RFLP assays of the SAG2 gene, in addition to RH strain. Swiss mice were infected intraperitoneally with 10(2) tachyzoites from each strain of T. gondii and treated with 6.25, 12.5, 25 and 50 mg/Kg/day of atovaquone or 40, 80, 160 and 320 mg/Kg/day of sulfadiazine. In a second experiment, mice were treated with the association of previously determined doses of each drug. Treatment started 48 hours post-infection, and lasted 10 days. The susceptibility of T. gondii to atovaquone and to sulfadiazine was different according to the parasite strain. It was observed strains that are susceptible to atovaquone, and strains that are resistant to it. Type I strains were more susceptible to the activity of sulfadiazine and more resistant to atovaquone. Yet type III strains were susceptible to atovaquone and to sulfadiazine. Association of atovaquone and sulfadiazine presented a synergic effect in the treatment of mice infected with RH type I strain and an additive effect in the treatment of mice infected with one type I strain and with two type III strains.     

Efficacy of interferon-gamma and amphotericin B for the treatment of systemic murine histoplasmosis

The number of cases of systemic histoplasmosis has increased substantially in recent years, and improved therapy is needed. We examined the efficacy of immunomodulation with interferon (IFN)-gamma alone or in combination with a suboptimal regimen of amphotericin B for the treatment of primary systemic murine histoplasmosis. In the first study, BALB/c mice were infected with Histoplasma capsulatum G217B and treated with 10(5) U of IFN given every other day either preinfection and postinfection or only postinfection, alone or in combination with amphotericin B. IFN alone given subcutaneously (s.c.) postinfection prolonged survival over untreated controls (P < 0.01), whereas intravenous (i.v.) administration was ineffective. All combination regimens and amphotericin B alone significantly prolonged survival (P < 0.0001). The combination regimens of amphotericin B and IFN i.v. (pre- and postinfection) or IFN s.c. (postinfection) reduced the fungal burden in the liver and spleen; the latter regimen had superior efficacy in the spleen (P < 0.05) to either amphotericin B or IFN alone. After infection with a low-challenge inoculum, IFN given s.c. (pre- and postinfection) alone caused a significant reduction in fungal burden in the spleen (P < 0.001). In an acutely lethal model, combination regimens of IFN s.c. or i.v. and amphotericin B again prolonged survival (P < 0.01-0.001), with amphotericin B plus IFN given s.c. (pre- and postinfection) superior to all regimens (P < 0.05-0.01). This regimen also showed enhanced efficacy in causing the reduction of fungal burden in the spleen (P < 0.05). These results indicate that IFN in combination with AmB shows enhanced efficacy in the treatment of systemic histoplasmosis and support the potential utility of IFN as an adjunctive therapy.     

Evaluation of parasitological and molecular techniques for the diagnosis and assessment of cure of schistosomiasis mansoni in a low transmission area

This study evaluated parasitological and molecular techniques for the diagnosis and assessment of cure of schistosomiasis mansoni. A population-based study was performed in 201 inhabitants from a low transmission locality named Pedra Preta, municipality of Montes Claros, state of Minas Gerais, Brazil. Four stool samples were analysed using two techniques, the Kato-Katz^® (KK) technique (18 slides) and the TF-Test^®, to establish the infection rate. The positivity rate of 18 KK slides of four stool samples was 28.9% (58/201) and the combined parasitological techniques (KK+TF-Test^®) produced a 35.8% positivity rate (72/201). Furthermore, a polymerase chain reaction (PCR)-ELISA assay produced a positivity rate of 23.4% (47/201) using the first sample. All 72 patients with positive parasitological exams were treated with a single dose of Praziquantel^® and these patients were followed-up 30, 90 and 180 days after treatment to establish the cure rate. Cure rates obtained by the analysis of 12 KK slides were 100%, 100% and 98.4% at 30, 90 and 180 days after treatment, respectively. PCR-ELISA revealed cure rates of 98.5%, 95.5% and 96.5%, respectively. The diagnostic and assessment of cure for schistosomiasis may require an increased number of KK slides or a test with higher sensitivity, such as PCR-ELISA, in situations of very low parasite load, such as after therapeutic interventions.     

Performance and Safety of Praziquantel for Treatment of Intestinal Schistosomiasis in Infants and Preschool Children

Background

In 2012 the WHO formally recognised that infants and preschool children are at significant risk of schistosomiasis and qualify for treatment with praziquantel (PZQ). Targeted surveys determining both the performance and safety of this drug are now needed in endemic areas. We have formally assessed parasitological cure and putative side-effects in a prospective cohort of Schistosoma mansoni-infected children (aged 5 months–7 years old) in lakeshore settings of Uganda.

Methodology/Principal Findings

From a total of 369 children found to be egg-patent for intestinal schistosomiasis, 305 were followed-up three to four weeks after PZQ treatment and infection status re-assessed. Separately, a previously tested side-effect questionnaire was employed before and 24 hours after PZQ treatment to assess incidence and amelioration of symptoms in young children and their mothers. While the overall observed parasitological cure was 56.4%, a significant difference was found between a sub-set of children who had a history of multiple PZQ treatments (between one and four in an 18 month period), where cure rate was 41.7%, and those who had never received treatment (cure rate was 77·6%). PZQ proved to be safe, with only mild reported side effects which cleared within a month after treatment. Prevalence of reported symptoms was significantly lower in children than in mothers, and fewer side-effects were reported upon subsequent rounds of PZQ treatment.

Conclusion/Significance

Our findings show that PZQ treatment of young children resulted in satisfactory cure rates, and marked reduction in egg-output, with only mild and transient reported side-effects. However, the cure rate is clearly lower in younger children and those with history of previous treatment. Cure rate, but not egg reduction rate, was also lower in children with heavier pre-intervention infection intensity. With chemotherapy now recommended as a long-term strategy for disease control in young children, research into optimising the periodicity of targeted treatment strategies is now crucial.     

Biogenic silver nanoparticles reduce Toxoplasma gondii infection and proliferation in RAW 264.7 macrophages by inducing tumor necrosis factor-alpha and reactive oxygen species production in the cells

Owing to the serious adverse effects caused by pyrimethamine and sulfadiazine, the drugs commonly used to treat toxoplasmosis, there is a need for treatment alternatives for this disease. Nanotechnology has enabled significant advances toward this goal. This study was conducted to evaluate the activity of biogenic silver nanoparticles (AgNp-Bio) in RAW 264.7 murine macrophages infected with the RH strain of Toxoplasma gondii. The macrophages were infected with T. gondii tachyzoites and then treated with various concentrations of AgNp-Bio. The cells were evaluated by microscopy, and culture supernatants were collected for ELISA determination of their cytokine concentration. Treatment with 6 μM AgNp-Bio reduced the infection and parasite load in infected RAW 264.7 macrophages without being toxic to the cells. The treatment also induced the synthesis of reactive oxygen species and tumor necrosis factor-alpha (both pro-inflammatory mediators), which resulted in ultrastructural changes in the tachyzoites and their intramacrophagic destruction. Our findings suggest that AgNp-Bio affect T. gondii tachyzoites by activating microbicidal and pro-inflammatory mechanisms and may be a potential alternative treatment for toxoplasmosis.     

The therapeutic use of isometamidium chloride against Cryptobia salmositica in rainbow trout Oncorhynchus mykiss.

Rainbow trout Oncorhynchus mykiss injected intramuscularly with isometamidium chloride (0.01 or 0.1 mg kg-1) at 3 wk post-infection and given a booster 2 wk later had significantly lower parasitaemias than infected controls. Packed cell volume increased after treatment and remained higher than in infected controls. The concentration of isometamidium in plasma was highest at 2 wk after injection and then declined. An intramuscular dose of 1.0 mg kg-1 of isometamidium chloride at 1, 2 and 3 wk postinfection (preclinical) significantly reduced the parasitaemia in rainbow trout 2 wk after treatment. A booster at 9 wk postinfection (chronic disease phase) reduced the parasitaemia further in all fish. The packed cell volume in these fish was higher than in infected controls. Treatment at 5, 6, and 7 wk postinfection (acute disease) had no effects and parasitaemias in treated fish were higher than in infected controls; also, anti-Cryptobia salmositica antibodies and titres of complement-fixing antibody were higher in these than in infected controls. Incubation of immune plasma or complement with isometamidium for 3 h did not affect the lytic titres of complement-fixing antibodies nor rainbow trout complement.     

A Systematic Review and Meta-Analysis of the Efficacy of Anti-Toxoplasma gondii Medicines in Humans

No effective drug and definitive “gold standard” treatment for Toxoplasma gondii (T. gondii) infection has been available so far, though some medicines have been commonly used in the treatment of T. gondii infection, such as spiramycin, azithromycin, traditional Chinese medicine (TCM), pyrimethamine- sulfadiazine (P-S), trimethoprim-sulfamethoxazole (TMP-SMX), and pyrimethamine-clindamycin (P-C). A systematic review and meta-analysis were performed to compare the efficacies of these conventional medicines in the treatment. Cohort studies for the treatment of acute T. gondii infection were searched from PubMed, Google Scholar, ect. All the cases number for different group extracted from each included literature were input to meta-analysis 3.13 software to calculate the pooled negative conversion rate (NCR), cure rate (CR) or vertical transmission rate based on their sample size and weight. The pooled NCR with 95% confidence intervals (CI) was used to evaluate the overall rate of a diagnosis positive result conversion to a negative result after treatment, which of spiramycin, azithromycin and TCM were 83.4% (95%CI, 72.1%-90.8%), 82.5% (95%CI, 75.9%-87.6%), and 85.5% (95%CI, 71.3%-93.3%) respectively, with no statistical difference between them. The pooled CR with 95% CI was used to evaluate the overall rate of complete disappearance of clinical symptoms for toxoplasmic encephalitis after therapy, which of P-S, TMP-SMX, and P-C were 49.8% (95%CI, 38. 8% -60.8%), 59.9% (95%CI, 48.9%-70.0%), and 47.6% (95%CI, 24.8%-71.4%) respectively, with no statistical difference between them. Primary T. gondii infection in pregnancy was treated mainly with spiramycin alone or combined with other drugs, and the pooled rate of vertical transmission was about 9.9% (95%CI, 5.9%-16.2%) after therapy. Toxoplasmic encephalitis in AIDS patients was usually treated with sulfonamides combined with other drugs and the pooled CR was 49.4% (95%CI, 37.9%-60.9%).     

An Alternative Non-Macrolide, Non-Imidazole Treatment Regimen for Curing Helicobacter pylori and Duodenal Ulcers: Ranitidine Bismuth Citrate Plus Amoxicillin

Background. Because patients who fail to be cured of H. pylori infection following macrolide or imidazole therapy are difficult to treat, there is a clear need for a reasonably effective and simple second-line treatment regimen. The purpose of these two studies was to evaluate the efficacy of ranitidine bismuth citrate (RBC) plus amoxicillin for the cure of H. pylori infection and for healing duodenal ulcers and preventing ulcer relapse.
Materials and Methods. Two identically designed randomized, double-blind, double-dummy studies were conducted in patients with an H. pylori -associated duodenal ulcer. Patients were treated with either RBC 400 mg bid for 4 weeks plus amoxicillin 500 mg qid for 2 weeks, RBC 400 mg bid for 4 weeks and placebo qid for 2 weeks, placebo bid for 4 weeks and amoxicillin 500 mg qid for 2 weeks, or placebo bid for 4 weeks and placebo qid for 2 weeks. Patients with healed ulcers after 4 weeks of treatment were eligible for entry into a 24-week observation phase for the assessment of H. pylori status (culture, histology, and CLOtest^TM) and ulcer relapse.
Results. A total of 229 patients with confirmed H. pylori infection at baseline were evaluated. Of these, 132 whose ulcers had healed entered the 24-week posttreatment observation phase. The combination of RBC plus amoxicillin resulted in higher H. pylori cure rates (55%) and higher duodenal ulcer healing (74%) than did either treatment alone. All treatments were well tolerated.
Conclusions. The combination of ranitidine bismuth citrate plus amoxicillin cures H. pylori infection in more than half of the patients treated. This treatment regimen shows promise as the basis for future non-macrolide, non-imidazole triple therapy regimens for curing H. pylori infection. Such regimens may be appropriate second-line treatment for patients who are resistant to or who are unable to tolerate macrolide- or imidazole-containing therapies.     

Plasmodium yoelii: activity of azithromycin in combination with pyrimethamine or sulfadoxine against blood and sporozoite induced infections in Swiss mice

The efficacy of pyrimethamine or sulfadoxine administered in combination with azithromycin was examined in a rodent malaria model. Outbred Swiss mice infected with blood stage parasites were treated from day 0 to day 3 and efficacy of different regimens was monitored in terms of the curative response and the delay time to reach 2% parasitaemia (2% DT). Administration of azithromycin alone at 60 mg/kg/day produced curative response while lower doses showed marginally delayed 2% DT. A marked potentiation in activities of pyrimethamine (100-fold) or sulfadoxine (10-fold) was observed when administered at non-curative doses of 0.1 mg/kg/day in combination with azithromycin (30 mg/kg/day) against blood stage parasites. A combination of 10 mg/kg/day azithromycin with 0.3 mg/kg/day sulfadoxine was also curative. Likewise in the causal prophylactic test, a combination regimen comprising 1/16th and 1/3rd the individual curative doses of pyrimethamine and azithromycin, respectively, prevented the development of patent infection after Plasmodium yoelii sporozoite challenge. Our results suggest that a combination of azithromycin with the second line treatment regimen of fansidar may enhance the therapeutic efficacy of the latter and also provide better prophylaxis against Plasmodium falciparum malaria.     

Combined treatment of heterocyclic analogues and benznidazole upon Trypanosoma cruzi in vivo

Chagas disease caused by Trypanosoma cruzi is an important cause of mortality and morbidity in Latin America but no vaccines or safe chemotherapeutic agents are available. Combined therapy is envisioned as an ideal approach since it may enhance efficacy by acting upon different cellular targets, may reduce toxicity and minimize the risk of drug resistance. Therefore, we investigated the activity of benznidazole (Bz) in combination with the diamidine prodrug DB289 and in combination with the arylimidamide DB766 upon T. cruzi infection in vivo. The oral treatment of T.cruzi-infected mice with DB289 and Benznidazole (Bz) alone reduced the number of circulating parasites compared with untreated mice by about 70% and 90%, respectively. However, the combination of these two compounds decreased the parasitemia by 99% and protected against animal mortality by 100%, but without providing a parasitological cure. When Bz (p.o) was combined with DB766 (via i.p. route), at least a 99.5% decrease in parasitemia levels was observed. DB766+Bz also provided 100% protection against mice mortality while Bz alone provided about 87% protection. This combined therapy also reduced the tissular lesions induced by T. cruzi infection: Bz alone reduced GPT and CK plasma levels by about 12% and 78% compared to untreated mice group, the combination of Bz with DB766 resulted in a reduction of GPT and CK plasma levels of 56% and 91%. Cure assessment through hemocultive and PCR approaches showed that Bz did not provide a parasitological cure, however, DB766 alone or associated with Bz cured ≥13% of surviving animals.     

Plasmodium falciparum: drug-resistant malaria complicating leukemias and lymphomas in children.

The present communication deals with drug-resistant Plasmodium falciparum malaria complicating hematologic malignancies (leukemias, n = 24, and lymphomas, n = 7) in children. Of 50 cases of hematologic malignancies, 31 patients were microscopically diagnosed as having P. falciparum infection (MP +). Initially, all the patients were treated with chloroquine. The results of primary treatment showed chloroquine resistance in 16 (51. 62%) cases. Of these 16 chloroquine-resistant cases, 13 were secondarily treated with a combination of pyrimethamine plus sulfamethopyrazine. The results of secondary treatment also revealed resistance to pyrimethamine plus sulfamethopyrazine in 6 of 13 (46. 10%) cases. The 6 pyrimethamine plus sulfamethopyrazine-resistant P. falciparum cases were finally cured by quinine therapy, against which no resistance was encountered. Conversely, in the control group comprising 38 cases of P. falciparum without malignancy, the incidence of chloroquine resistance was found in only 9 cases, which is rather low (23.70%). Of these 7 chloroquine-resistant cases, 5 were found to be sensitive to pyrimethamine plus sulfamethopyrazine treatment, while the 2 nonresponders were finally cured with quinine. The overall results of this study show a high prevalence of chloroquine resistance among clinical cases of falciparum malaria (25/69; 30.6%). Among the nonresponders (n = 20) 40% of cases were also resistant to the pyrimethamine plus sulfamethopyrazine combination. There was no resistance to quinine.     

Benznidazole and Posaconazole in Experimental Chagas Disease: Positive Interaction in Concomitant and Sequential Treatments

Background

Current chemotherapy for Chagas disease is unsatisfactory due to its limited efficacy, particularly in the chronic phase, with frequent side effects that can lead to treatment discontinuation. Combined therapy is envisioned as an ideal approach since it may improve treatment efficacy whilst decreasing toxicity and the likelihood of resistance development. We evaluated the efficacy of posaconazole in combination with benznidazole on Trypanosoma cruzi infection in vivo.

Methods and Findings

Benznidazole and posaconazole were administered individually or in combination in an experimental acute murine infection model. Using a rapid treatment protocol for 7 days, the combined treatments were more efficacious in reducing parasitemia levels than the drugs given alone, with the effects most evident in combinations of sub-optimal doses of the drugs. Subsequently, the curative action of these drug combinations was investigated, using the same infection model and 25, 50, 75 or 100 mg/kg/day (mpk) of benznidazole in combination with 5, 10 or 20 mpk of posaconazole, given alone or concomitantly for 20 days. The effects of the combination treatments on parasitological cures were higher than the sum of such effects when the drugs were administered separately at the same doses, indicating synergistic activity. Finally, sequential therapy experiments were carried out with benznidazole or posaconazole over a short interval (10 days), followed by the second drug administered for the same period of time. It was found that the sequence of benznidazole (100 mpk) followed by posaconazole (20 mpk) provided cure rates comparable to those obtained with the full (20 days) treatments with either drug alone, and no cure was observed for the short treatments with drugs given alone.

Conclusions

Our data demonstrate the importance of investigating the potential beneficial effects of combination treatments with marketed compounds, and showed that combinations of benznidazole with posaconazole have a positive interaction in murine models of Chagas disease.     

Collaborative overview of randomised trials of antiplatelet therapy--II: Maintenance of vascular graft or arterial patency by antiplatelet therapy. Antiplatelet Trialists' Collaboration.

OBJECTIVE--To determine the efficacy of antiplatelet therapy in maintaining vascular patency in various categories of patients. DESIGN--Overviews of 46 randomised trials of antiplatelet therapy versus control and 14 randomised trials comparing one antiplatelet regimen with another. SETTING--Randomised trials that could have been available by March 1990 and in which vascular graft or arterial patency was to be studied systematically. SUBJECTS--About 8000 patients at varying degrees of risk of vascular occlusion (by virtue of disease or of having some vascular procedure) were in trials of antiplatelet therapy versus control and 4000 such patients were in trials directly comparing different antiplatelet regimens. RESULTS--Overall, antiplatelet therapy produced a highly significant (2P < 0.0001) reduction in vascular occlusion, with similar proportional reductions in several different types of patients. Hence the absolute reductions tended to be largest among patients at highest risk of occlusion, with smaller but still significant absolute reductions among lower risk patients. The proportions of patients with confirmed occlusion among those allocated antiplatelet therapy versus appropriately adjusted control proportions (and mean scheduled treatment durations and net absolute benefits) were: (a) among about 4000 patients with coronary artery grafts, 21% antiplatelet therapy v 30% control (seven month benefit about 90 patients protected per 1000 allocated antiplatelet therapy (2P < 0.00001)); (b) among about 800 patients after coronary angioplasty, 4% antiplatelet therapy v 8% control (six month benefit about 40/1000 (2P = 0.02)); (c) among about 3000 patients with peripheral artery procedures or disease, 16% antiplatelet therapy v 25% control (19 month benefit about 90/1000 (2P < 0.00001)); (d) among about 400 renal patients with a shunt or fistula placed for haemodialysis access, 17% antiplatelet therapy v 39% control (two month benefit about 200/1000 (2P < 0.00001)). Indirect comparisons between the effects of starting treatment before these vascular procedures and starting soon after them indicated similar sized benefits. As well as preventing subclinical occlusion, antiplatelet therapy produced a significant (2P = 0.002) reduction of about one quarter in the odds of suffering a "vascular event" (non-fatal myocardial infarction, non-fatal stroke, or vascular death). Various antiplatelet regimens (chiefly aspirin alone or aspirin plus dipyridamole) were studied but there was no significant evidence of differences between their effects on arterial occlusion or vascular events. Data on bleeding were incomplete but no large excess with antiplatelet therapy was apparent. CONCLUSION--Antiplatelet therapy (chiefly aspirin alone or aspirin plus dipyridamole) greatly reduces the risk of vascular occlusion in a wide range of patients at high risk of this complication. Further studies are required to determine exactly when treatment should start (to limit any perioperative bleeding while still preventing most early occlusion) and for how long it should be continued.     

Electrogene therapy with p53 of murine sarcomas alone or combined with electrochemotherapy using cisplatin

The aim of our study was to evaluate feasibility and therapeutic potential of electrogene therapy with p53 alone or combined with electrochemotherapy using cisplatin on two murine sarcomas with different p53 status. Antitumor effectiveness of three consecutive electrogene treatments with p53 was more effective in wild-type LPB tumors than mutated SA-1 tumors, resulting in 21.4% of tumor cures in LPB tumors and 12.5% in SA-1 tumors. Pretreatment of tumors with electrogene therapy with p53 enhanced chemosensitivity of both tumor models treated by electrochemotherapy with cisplatin. After only one application of this treatment combination in the LPB tumor model, specific tumor growth delay was prolonged in the combined treatment group compared to electrogene therapy with p53 or electrochemotherapy with cisplatin alone, whereas in SA-1 tumors this treatment combination resulted in 31.6% of cured animals. Results of our study show that electrogene therapy with p53 alone or combined with electrochemotherapy is feasible and effective treatment of tumors. The combination of electrogene therapy and electrochemotherapy after only one application resulted in complete regression of tumors.