Potent, Plasmodium-selective farnesyltransferase inhibitors that arrest the growth of malaria parasites: structure-activity relationships of ethylenediamine-analogue scaffolds and homology model validation

New chemotherapeutics are urgently needed to combat malaria. We previously reported on a novel series of antimalarial, ethylenediamine-based inhibitors of protein farnesyltransferase (PFT). In the current study, we designed and synthesized a series of second generation inhibitors, wherein the core ethylenediamine scaffold was varied in order to examine both the homology model of Plasmodium falciparum PFT (PfPFT) and our predicted inhibitor binding mode. We identified several PfPFT inhibitors (PfPFTIs) that are selective for PfPFT versus the mammalian isoform of the enzyme (up to 136-fold selectivity), that inhibit the malarial enzyme with IC50 values down to 1 nM, and that block the growth of P. falciparum in infected whole cells (erythrocytes) with ED50 values down to 55 nM. The structure-activity data for these second generation, ethylenediamine-inspired PFT inhibitors were rationalized by consideration of the X-ray crystal structure of mammalian PFT and the homology model of the malarial enzyme.     

Hemangioma of the spleen. A case report

We report a case of hemangioma of the spleen in an 18-old-years female patient. Clinical presentation was abdominal pain in the left upper quadrant. Physical examination founding was normal. The hemangioma was presented as hyperechogenic mass on ultra sound imaging. On the computed tomography scan with contrast it became progressively hyperdense. Splenectomy is often indicated because of the risk of rupture and the doubt about malignant form in histological examination.     

Bioavailability of vitamin B₁₂ in cows' milk

The natural source of vitamin B?? in human diets comes from animal products. For example, one glass (250 ml) of milk provides approximately 50 % of the RDA (2·4 μg/d). It was hypothesised that the provision of vitamin B?? from milk is more efficiently absorbed than the synthetic form used in vitamin supplements. Pigs (n 10) were used as a model for intestinal absorption of vitamin B?? in humans to compare the net fluxes of vitamin B?? across the portal-drained viscera (PDV; an indicator of intestinal absorption) after ingestion of meals complemented with conventional and vitamin B??-enriched (via injections to cows) milk (raw, pasteurised or microfiltrated) or with equivalent amounts of cyanocobalamin, the synthetic form used in supplements or unsupplemented. Net flux of vitamin B?? across PDV after the ingestion of milk was positive, though not influenced by milk enrichment (P>0·3) or technological processes (P = 0·8) and was greater than after ingestion of equivalent amounts of cyanocobalamin (cyanocobalamin v. all milk, P ≤ 0·003). In fact, net fluxes of this vitamin were not different from 0 after either cyanocobalamin or the meal devoid of vitamin B?? (unsupplemented v. cyanocobalamin, P = 0·7). The cumulative PDV fluxes during the 24 h following ingestion of meals complemented with milk varied from 5·5 to 6·8 μg. These values correspond to an efficiency of intestinal absorption of vitamin B?? from milk varying between 8 and 10 %. Therefore, vitamin B??, which is abundant in cows' milk, is also substantially more available than the most commonly used synthetic form of this vitamin.     

A network RER rooted on in vitro readout assays of Plasmodium falciparum sensitivity to chloroquine in the Indian Ocean Region

Chloroquine has been used as a first line drug to treat uncomplicated malaria cases during the last five decades in Madagascar and in the Comoros Union. The four plasmodial species known to infect humans occur on Madagascar Island. Chloroquine-resistant malaria cases, sometimes only suspected from presumptive malaria cases, have been reported in both countries. Thus, to redefine a strategy and a policy to cure malaria, there is a need to get relevant and updated data. In December 1999, the Madagascan Ministry of Health and the Institut Pasteur de Madagascar formed a network named RER for malaria resistance surveillance. In 2000 and 2001, 18 study sites (17 throughout Madagascar and 1 in Comoros) joined this network. Health-care workers were trained mainly for malaria diagnosis through the use of blood smear examination and for malaria case management. To alleviate the lack of competent medical teams within the health centres, and for technical and logistic reasons, as part of the network activities, it was decided to start with in vitro tests to assess the sensitivity of P.falciparum isolates to chloroquine by means of the isotopic method. Parasitized blood samples were collected from consenting patients. P.falciparum isolates were more predominant (989/1,036). Out of the 564 tests done, 432 (76.6%) could be assessed. Results demonstrated that 94.3% (381/404) of the Madagascan P.falciparum isolates were susceptible to chloroquine. In contrast, chloroquine-resistant isolates were prevalent in Comoros (8/28). The network set-up is presented. The usefulness of the in vivo approach and of the in vitro investigations (chemosusceptibility test and screening of mutations accounting for resistance to chloroquine) to monitor the emergence and the dissemination of chloroquine-resistant parasites is discussed.     

In-Vitro Assessment of the Acaricidal Properties of Artemisia annua and Zataria multiflora Essential Oils to Control Cattle Ticks

Background

The aim of this study was to investigate the ‘acaricidal effect’ of Zataria multiflora and Artemisia annua essential oils on Rhipicephalus (Boophilus) annulatus.

Methods

This study was carried out in 2009 in the Laboratory of Parasitology of the Faculty of Veterinary Medicine of Shahrekord University, west central Iran. Six dilutions (5, 10, 20, 40, 60 and 80 µL/cm³) of both essential oils were used against engorged female R. (Boophilus) annulatus ticks using an in vitro immersion method. The mortality rates for each treatment were recorded 6, 15 and 24 hours post inoculation (hpi). Mortality rate was analyzed using Repeated Measures Analysis of Variance, and comparison of means was carried out using General Linear Models Procedure.

Results

The mortality rate caused by different dilutions of Z. multiflora essential oil ranged from 26.6% (using 10 µL/cm³) to 100% (using 40 µL/cm³) and for A. annua essential oil it was 33.2 to 100% (using 20 and 80 µL/cm³, respectively) by the end of the experiment (36 hpi). No mortality was recorded for the non-treated control group or for dilutions less than 5 and 10 µL/cm³ using Zataria and Artemisia essential oils, respectively. For Z. multiflora mortality peaked at 15 hpi for all concentrations other than 20 µL/cm³ and took 24 h to achieve its maximum effect while for A. annua the two highest concentrations needed 24 hpi to reach their full effect. In addition, essential oils applied at more than 20 and 60 µL/cm³ caused 100% egg-laying failure in engorged female ticks by Zataria and Artemisia, respectively while no failure was observed for the non-treated control group. The mortality rate in both botanical acaricides was dose-dependent.

Conclusion

Both these medicinal plants have high potential acaricidal effects on the engorged stage of R. (Boophilus) annulatus in vitro.     

Correlation between exposure to phthalates and concentrations of malondialdehyde in infants and children undergoing cyclic parenteral nutrition

Background: Plasticizers such as di(2‐ethylhexyl) phthalate (DEHP) are added to polyvinyl chloride (PVC) to confer flexibility. However, DEHP is associated with reproductive disorders in humans. Because of its noncovalent bond to the PVC matrix, this plasticizer tends to leach easily. Infants and children undergoing cyclic, long‐term parenteral nutrition (PN) could be particularly at risk of potential toxicity from DEHP due to regular exposure. Malondialdehyde (MDA) is one of the most commonly used markers of free radical activity. The purpose of this study was to investigate how long‐term exposure to phthalate affects the plasmatic rate of MDA. Methods: Studies were performed on 7 randomized infants and children on regular cyclic, long‐term PN, and the results were compared with those of 5 nontreated infants. The circulating concentrations of DEHP in children and infants during the PN therapy were measured by high‐performance liquid chromatography. The concentrations were assessed before and after the PN session. In the same way, plasma MDA concentrations were measured. Results: The circulating concentrations of DEHP before and after a 10‐ to 11‐hour cyclic PN treatment in 7 infants and children under regular perfusion ranged widely, showing a significant increase after the treatment among all the patients. The same phenomenon observed with the rate of MDA showed that the 2 events are closely dependent. Therefore, long‐term exposure to DEHP during cyclic PN raised plasma MDA levels, indicating increased oxidative stress. Conclusion: Long‐term exposure to DEHP during PN increased free radical activity in vivo.     

Association between chronic morbidity and early retirement in Italy

Objectives

To examine the association between early retirement and presence of chronic morbidity in an Italian working population approaching the statutory pension age.

Methods

The study population consisted of men and women aged 45–59 years, employed at some time in the past (n = 18,547), who participated in a national cross-sectional survey, conducted in 2005. By means of a standardized questionnaire, information was collected on employment status, chronic diseases, and sociodemographics. The outcome was being retired as of the survey date. The association with number of diseases reported and specific long-term illnesses was assessed through multivariate Poisson regression models with robust standard errors, adjusted for potential confounders (p < 0.05).

Results

In the final multivariable models, people with poorer health were more likely to retire earlier. Diseases of the nervous system, malignant tumors, myocardial infarction, other cardiac diseases, and arthrosis/arthritis were the illnesses most strongly associated with early retirement; furthermore, the risk of retirement increased linearly as the number of diseases reported increased. Among other covariates, age, area of residence, educational level, and occupational social class were also significantly associated with the outcome. Occupational social class significantly modified the association between morbidity and retirement in men, among whom a higher risk of retirement associated with morbidity was observed in the highest, compared with lower social classes.

Conclusions

A statistically significant and independent association between chronic morbidity and early retirement was observed among subjects approaching the statutory pension age, suggesting the need to develop interventions to improve prevention and treatment of chronic conditions.

     

Growth hormone to improve short bowel syndrome intestinal autonomy: a pediatric randomized open-label clinical trial

Background: The ability of growth hormone (GH) to promote the weaning‐off of parenteral nutrition (PN) in short bowel syndrome (SBS) is unclear. No randomized controlled study is available in children. This study was undertaken to determine if GH could enhance the weaning off of PN in PN‐dependent children with SBS. Methods: A prospective randomized open‐label multicenter study was performed in 14 patients (mean age, 9 ± 1.4 years) with SBS (average small bowel length, 33 cm) and long‐term PN dependency (8 years) on an unrestricted diet. A standardized PN decrease with and without GH (0.14 mg/kg/d) was conducted. The patients were randomized to either a GH group (4 months of GH) or a control (CTR) group (4 months without GH, followed by 4 months with GH). Blood tests and a nutrition assessment of enteral and parenteral intakes were performed. Groups were compared with the Wilcoxon test. Results: Treatment with GH did not improve the weaning off of PN (decrease in PN caloric intake of 32.5% ± 9.6% in the GH group vs 35.2% ± 8.7% in the CTR group, nonsignificant). In the CTR group, GH treatment induced an additional but not statistically significant decrease of 8.8% ± 12.4% in daily calories. Parenteral needs returned to near basal rates 6 months after GH discontinuation (GH: 77.6% ± 10.6% vs CTR: 73.2% ± 7.4%). Weight decreased slightly in both groups. No biological parameters varied significantly. Conclusions: GH did not improve the weaning off of PN in PN‐dependent children with SBS.     

Pharmacological characterization of the TRPV1 receptor antagonist JYL1421 (SC0030) in vitro and in vivo in the rat

The TRPV1 capsaicin receptor is an integrator molecule on primary afferent neurones participating in inflammatory and nociceptive processes. The present paper characterizes the effects of JYL1421 (SC0030), a TRPV1 receptor antagonist, on capsaicin-evoked responses both in vitro and in vivo in the rat. JYL1421 concentration-dependently (0.1-2 microM) inhibited capsaicin-evoked substance P, calcitonin gene-related peptide and somatostatin release from isolated tracheae, while only 2 microM resulted in a significant inhibition of electrically induced neuropeptide release. Capsazepine (0.1-2 microM), as a reference compound, similarly diminished both capsaicin-evoked and electrically evoked peptide release. JYL1421 concentration-dependently decreased capsaicin-induced Ca(2+) accumulation in cultured trigeminal ganglion cells, while capsazepine was much less effective. In vivo 2 mg/kg i.p. JYL1421, but not capsazepine, inhibited capsaicin-induced hypothermia, eye wiping movements and reflex hypotension (a component of the pulmonary chemoreflex or Bezold-Jarisch reflex). Based on these data JYL1421 is a more selective and in most models also a more potent TRPV1 receptor antagonist than capsazepine, therefore it may promote the assessment of the (patho)physiological roles of the TRPV1 receptor.     

Novel 2(3H)-Benzothiazolones as Highly Potent and Selective Sigma-1 Receptor Ligands

In an effort to produce a new pharmacological probe with high affinity and selectivity for the sigma-1 receptor, we have synthesized a series of original 2(3H)-benzothiazolones utilizing compound 4 [3-(1-piperidinoethyl)-6-propylbenzothiazolin-2-one] as a lead. Receptor binding affinities were determined at sigma-1 and sigma-2 receptors. The best ligand (9, sigma-1 K_i = 0.56 nM, selectivity ratio >1000) was obtained with an azepine side-chain. When tested on a wide battery of receptors, including 5HT_2A(h), 5HT₃(h), α₁, α ₂, β₁, β₂, H₁, H₂, opioids, D₁(h), D₂(h), 5HT uptake, and DOPA uptake, compound 9 showed submicromolar affinity only for α₂ (K_i = 205 nM) and H₁ (K_i = 311 nM).