Low dose aspirin prevents endothelial dysfunction in the aorta and foetal loss in pregnant mice infected with influenza A virus

Influenza A virus (IAV) infection in pregnancy resembles a preeclamptic phenotype characterised by vascular dysfunction and foetal growth retardation. Given that low dose aspirin (ASA) is safe in pregnancy and is used to prevent preeclampsia, we investigated whether ASA or NO-conjugated aspirin, NCX4016, resolve vascular inflammation and function to improve offspring outcomes following IAV infection in pregnant mice. Pregnant mice were intranasally infected with a mouse adapted IAV strain (Hkx31; 104 plaque forming units) and received daily treatments with either 200µg/kg ASA or NCX4016 via oral gavage. Mice were then culled and the maternal lungs and aortas collected for qPCR analysis, and wire myography was performed on aortic rings to assess endothelial and vascular smooth muscle functionality. Pup and placentas were weighed and pup growth rates and survival assessed. IAV infected mice had an impaired endothelial dependent relaxation response to ACh in the aorta, which was prevented by ASA and NCX4016 treatment. ASA and NCX4016 treatment prevented IAV dissemination and inflammation of the aorta as well as improving the pup placental ratios in utero, survival and growth rates at post-natal day 5. Low dose ASA is safe to use during pregnancy for preeclampsia and this study demonstrates that ASA may prove a promising treatment for averting the significant vascular complications associated with influenza infection during pregnancy.

TLR9 Monotherapy in Immune-Competent Mice Suppresses Orthotopic Prostate Tumor Development

Prostate cancer is ranked second in the world for cancer-related deaths in men, highlighting the lack of effective therapies for advanced-stage disease. Toll-like receptors (TLRs) and immunity have a direct role in prostate cancer pathogenesis, but TLR9 has been reported to contribute to both the progression and inhibition of prostate tumorigenesis. To further understand this apparent disparity, we have investigated the effect of TLR9 stimulation on prostate cancer progression in an immune-competent, syngeneic orthotopic mouse model of prostate cancer. Here, we utilized the class B synthetic agonist CPG-1668 to provoke a TLR9-mediated systemic immune response and demonstrate a significant impairment of prostate tumorigenesis. Untreated tumors contained a high abundance of immune-cell infiltrates. However, pharmacological activation of TLR9 resulted in smaller tumors containing significantly fewer M1 macrophages and T cells. TLR9 stimulation of tumor cells in vitro had no effect on cell viability or its downstream transcriptional targets, whereas stimulation in macrophages suppressed cancer cell growth via type I IFN. This suggests that the antitumorigenic effects of CPG-1668 were predominantly mediated by an antitumor immune response. This study demonstrated that systemic TLR9 stimulation negatively regulates prostate cancer tumorigenesis and highlights TLR9 agonists as a useful therapeutic for the treatment of prostate cancer.

TLR7 promotes chronic airway disease in RSV-infected mice

Respiratory syncytial virus (RSV) commonly infects the upper respiratory tract (URT) of humans, manifesting with mild cold or flu-like symptoms. However, in infants and the elderly, severe disease of the lower respiratory tract (LRT) often occurs and can develop into chronic airway disease. A better understanding of how an acute RSV infection transitions to a LRT chronic inflammatory disease is critically important to improve patient care and long-term health outcomes. To model acute and chronic phases of the disease, we infected wild-type C57BL/6 and toll-like receptor 7 knockout (TLR7 KO) mice with RSV and temporally assessed nasal, airway and lung inflammation for up to 42 days post-infection. We show that TLR7 reduced viral titers in the URT during acute infection but promoted pronounced pathogenic and chronic airway inflammation and hyperreactivity in the LRT. This study defines a hitherto unappreciated molecular mechanism of lower respiratory pathogenesis to RSV, highlighting the potential of TLR7 modulation to constrain RSV pathology to the URT.

Molecular basis for nuclear accumulation and targeting of the inhibitor of apoptosis BIRC2

The inhibitor of apoptosis protein BIRC2 regulates fundamental cell death and survival signaling pathways. Here we show that BIRC2 accumulates in the nucleus via binding of its second and third BIR domains, BIRC2BIR2 and BIRC2BIR3, to the histone H3 tail and report the structure of the BIRC2BIR3-H3 complex. RNA-seq analysis reveals that the genes involved in interferon and defense response signaling and cell-cycle regulation are most affected by depletion of BIRC2. Overexpression of BIRC2 delays DNA damage repair and recovery of the cell-cycle progression. We describe the structural mechanism for targeting of BIRC2BIR3 by a potent but biochemically uncharacterized small molecule inhibitor LCL161 and demonstrate that LCL161 disrupts the association of endogenous BIRC2 with H3 and stimulates cell death in cancer cells. We further show that LCL161 mediates degradation of BIRC2 in human immunodeficiency virus type 1-infected human CD4+ T cells. Our findings provide mechanistic insights into the nuclear accumulation of and blocking BIRC2.

Influenza A virus infection during pregnancy causes immunological changes in gut-associated lymphoid tissues of offspring mice

Maternal influenza A virus (IAV) infection during pregnancy can affect offspring immune programming and development. Offspring born from influenza-infected mothers are at increased risk of neurodevelopmental disorders and have impaired respiratory mucosal immunity against pathogens. The gut-associated lymphoid tissue (GALT) represents a large proportion of the immune system in the body and plays an important role in gastrointestinal (GI) homeostasis. This includes immune modulation to antigens derived from food or microbes, gut microbiota composition, and gut-brain axis signaling. Therefore, in this study, we investigated the effect of maternal IAV infection on mucosal immunity of the GI tract in the offspring. There were no major anatomical changes to the gastrointestinal tract of offspring born to influenza-infected dams. In contrast, maternal IAV did affect the mucosal immunity of offspring, showing regional differences in immune cell profiles within distinct GALT. Neutrophils, monocytes/macrophages, CD4+ and CD8+ T cells infiltration was increased in the cecal patch offspring from IAV-infected dams. In the Peyer's patches, only activated CD4+ T cells were increased in IAV offspring. IL-6 gene expression was also elevated in the cecal patch but not in the Peyer's patches of IAV offspring. These findings suggest that maternal IAV infection perturbs homeostatic mucosal immunity in the offspring gastrointestinal tract. This could have profound ramifications on the gut-brain axis and mucosal immunity in the lungs leading to increased susceptibility to respiratory infections and neurological disorders in the offspring later in life.NEW & NOTEWORTHY Influenza A virus (IAV) infection during pregnancy is associated with changes in gut-associated lymphoid tissue (GALT) in the offspring in a region-dependent manner. Neutrophils and monocytes/macrophages were elevated in the cecal patch of offspring from infected dams. This increase in innate immune cell infiltration was not observed in the Peyer's patches. T cells were also elevated in the cecal patch but not in the Peyer's patches.

Therapeutic Targeting of Endosome and Mitochondrial Reactive Oxygen Species Protects Mice From Influenza Virus Morbidity

There is an urgent need to develop effective therapeutic strategies including immunomodulators to combat influenza A virus (IAV) infection. Influenza A viruses increase ROS production, which suppress anti-viral responses and contribute to pathological inflammation and morbidity. Two major cellular sites of ROS production are endosomes via the NOX2-oxidase enzyme and the electron transport chain in mitochondria. Here we examined the effect of administration of Cgp91ds-TAT, an endosome-targeted NOX2 oxidase inhibitor, in combination with mitoTEMPO, a mitochondrial ROS scavenger and compared it to monotherapy treatment during an established IAV infection. Mice were infected with IAV (Hkx31 strain; 10⁴PFU/mouse) and 24 h post infection were treated with Cgp91ds-TAT (0.2 mg/kg), mitoTEMPO (100 μg) or with a combination of these inhibitors [Cgp91ds-TAT (0.2 mg/kg)/mitoTEMPO (100 μg)] intranasally every day for up to 2 days post infection (pi). Mice were euthanized on Days 3 or 6 post infection for analyses of disease severity. A combination of Cgp91ds-TAT and mitoTEMPO treatment was more effective than the ROS inhibitors alone at reducing airway and neutrophilic inflammation, bodyweight loss, lung oedema and improved the lung pathology with a reduction in alveolitis following IAV infection. Dual ROS inhibition also caused a significant elevation in Type I IFN expression at the early phase of infection (day 3 pi), however, this response was suppressed at the later phase of infection (day 6 pi). Furthermore, combined treatment with Cgp91ds-TAT and mitoTEMPO resulted in an increase in IAV-specific CD8⁺ T cells in the lungs. In conclusion, this study demonstrates that the reduction of ROS production in two major subcellular sites, i.e. endosomes and mitochondria, by intranasal delivery of a combination of Cgp91ds-TAT and mitoTEMPO, suppresses the severity of influenza infection and highlights a novel immunomodulatory approach for IAV disease management.

Mutagenic Consequences of Sublethal Cell Death Signaling

Many human cancers exhibit defects in key DNA damage response elements that can render tumors insensitive to the cell death-promoting properties of DNA-damaging therapies. Using agents that directly induce apoptosis by targeting apoptotic components, rather than relying on DNA damage to indirectly stimulate apoptosis of cancer cells, may overcome classical blocks exploited by cancer cells to evade apoptotic cell death. However, there is increasing evidence that cells surviving sublethal exposure to classical apoptotic signaling may recover with newly acquired genomic changes which may have oncogenic potential, and so could theoretically spur the development of subsequent cancers in cured patients. Encouragingly, cells surviving sublethal necroptotic signaling did not acquire mutations, suggesting that necroptosis-inducing anti-cancer drugs may be less likely to trigger therapy-related cancers. We are yet to develop effective direct inducers of other cell death pathways, and as such, data regarding the consequences of cells surviving sublethal stimulation of those pathways are still emerging. This review details the currently known mutagenic consequences of cells surviving different cell death signaling pathways, with implications for potential oncogenic transformation. Understanding the mechanisms of mutagenesis associated (or not) with various cell death pathways will guide us in the development of future therapeutics to minimize therapy-related side effects associated with DNA damage.

Smac mimetics can provoke lytic cell death that is neither apoptotic nor necroptotic

Smac mimetics, or IAP antagonists, are a class of drugs currently being evaluated as anti-cancer therapeutics. These agents antagonize IAP proteins, including cIAP1/2 and XIAP, to induce cell death via apoptotic or, upon caspase-8 deficiency, necroptotic cell death pathways. Many cancer cells are unresponsive to Smac mimetic treatment as a single agent but can be sensitized to killing in the presence of the cytokine TNFα, provided either exogenously or via autocrine production. We found that high concentrations of a subset of Smac mimetics could provoke death in cells that did not produce TNFα, despite sensitization at lower concentrations by TNFα. The ability of these drugs to kill did not correlate with valency. These cells remained responsive to the lethal effects of Smac mimetics at high concentrations despite genetic or pharmacological impairments in apoptotic, necroptotic, pyroptotic, autophagic and ferroptotic cell death pathways. Analysis of dying cells revealed necrotic morphology, which was accompanied by the release of lactate dehydrogenase and cell membrane rupture without prior phosphatidylserine exposure implying cell lysis, which occurred over a several hours. Our study reveals that cells incapable of autocrine TNFα production are sensitive to some Smac mimetic compounds when used at high concentrations, and this exposure elicits a lytic cell death phenotype that occurs via a mechanism not requiring apoptotic caspases or necroptotic effectors RIPK3 or MLKL. These data reveal the possibility that non-canonical cell death pathways can be triggered by these drugs when applied at high concentrations.

Plexin B2 Is a Regulator of Monocyte Apoptotic Cell Disassembly

Billions of cells undergo apoptosis daily and often fragment into small, membrane-bound extracellular vesicles termed apoptotic bodies (ApoBDs). We demonstrate that apoptotic monocytes undergo a highly coordinated disassembly process and form long, beaded protrusions (coined as beaded apoptopodia), which fragment to release ApoBDs. Here, we find that the protein plexin B2 (PlexB2), a transmembrane receptor that regulates axonal guidance in neurons, is enriched in the ApoBDs of THP1 monocytes and is a caspase 3/7 substrate. To determine whether PlexB2 is involved in the disassembly of apoptotic monocytes, we generate PlexB2-deficient THP1 monocytes and demonstrate that lack of PlexB2 impairs the formation of beaded apoptopodia and ApoBDs. Consequently, the loss of PlexB2 in apoptotic THP1 monocytes impairs their uptake by both professional and non-professional phagocytes. Altogether, these data identify PlexB2 as a positive regulator of apoptotic monocyte disassembly and demonstrate the importance of this process in apoptotic cell clearance.

The Proteasome Inhibitor Ixazomib Inhibits the Formation and Growth of Pulmonary and Abdominal Osteosarcoma Metastases in Mice

Osteosarcoma is the most common form of primary bone cancer. Over 20% of osteosarcoma patients present with pulmonary metastases at diagnosis, and nearly 70% of these patients fail to respond to treatment. Previous work revealed that human and canine osteosarcoma cell lines are extremely sensitive to the therapeutic proteasome inhibitor bortezomib in vitro. However, bortezomib has proven disappointingly ineffective against solid tumors including sarcomas in animal experiments and clinical trials. Poor tumor penetration has been speculated to account for the inconsistency between in vitro and in vivo responses of solid tumors to bortezomib. Here we show that the second-generation proteasome inhibitor ixazomib, which reportedly has enhanced solid tumor penetration compared to bortezomib, is toxic to human and canine osteosarcoma cells in vitro. We used experimental osteosarcoma metastasis models to compare the efficacies of ixazomib and bortezomib against primary tumors and metastases derived from luciferase-expressing KRIB or 143B human osteosarcoma cell lines in athymic mice. Neither proteasome inhibitor reduced the growth of primary intramuscular KRIB tumors, however both drugs inhibited the growth of established pulmonary metastases created via intravenous inoculation with KRIB cells, which were significantly better vascularized than the primary tumors. Only ixazomib slowed metastases from KRIB primary tumors and inhibited the growth of 143B pulmonary and abdominal metastases, significantly enhancing the survival of mice intravenously injected with 143B cells. Taken together, these results suggest ixazomib exerts better single agent activity against osteosarcoma metastases than bortezomib. These data provide hope that incorporation of ixazomib, or other proteasome inhibitors that penetrate efficiently into solid tumors, into current regimens may improve outcomes for patients diagnosed with metastatic osteosarcoma.

Proteasome inhibitors trigger mutations via activation of caspases and CAD, but mutagenesis provoked by the HDAC inhibitors vorinostat and romidepsin is caspase/CAD-independent

Genotoxic anti-cancer therapies such as chemotherapy and radiotherapy can contribute to an increase in second malignancies in cancer survivors due to their oncogenic effects on non-cancerous cells. Inhibition of histone deacetylase (HDAC) proteins or the proteasome differ from chemotherapy in that they eliminate cancer cells by regulating gene expression or cellular protein equilibrium, respectively. As members of these drug classes have been approved for clinical use in recent times, we investigated whether these two drug classes exhibit similar mutagenic capabilities as chemotherapy. The HDAC inhibitors vorinostat/SAHA and romidepsin/FK288 were found to induce DNA damage, and mis-repair of this damage manifested into mutations in clonogenically viable surviving cells. DNA damage and mutations were also detected in cells treated with the proteasome inhibitor bortezomib. Exposure to both drug classes stimulated caspase activation consistent with apoptotic cell death. Inhibition of caspases protected cells from bortezomib-induced acute (but not clonogenic) death and mutagenesis, implying caspases were required for the mutagenic action of bortezomib. This was also observed for second generation proteasome inhibitors. Cells deficient in caspase-activated DNase (CAD) also failed to acquire DNA damage or mutations following treatment with bortezomib. Surprisingly, vorinostat and romidepsin maintained an equivalent level of killing and mutagenic ability regardless of caspase or CAD activity. Our findings indicate that both drug classes harbour mutagenic potential in vitro. If recapitulated in vivo, the mutagenicity of these agents may influence the treatment of cancer patients who are more susceptible to oncogenic mutations due to dysfunctional DNA repair pathways.

Mutagenic assessment of chemotherapy and Smac mimetic drugs in cells with defective DNA damage response pathways

DNA damaging therapies can spur the formation of therapy-related cancers, due to mis-repair of lesions they create in non-cancerous cells. This risk may be amplified in patients with impaired DNA damage responses. We disabled key DNA damage response pathways using genetic and pharmacological approaches, and assessed the impact of these deficiencies on the mutagenicity of chemotherapy drugs or the "Smac mimetic" GDC-0152, which kills tumor cells by targeting XIAP, cIAP1 and 2. Doxorubicin and cisplatin provoked mutations in more surviving cells deficient in ATM, p53 or the homologous recombination effector RAD51 than in wild type cells, but suppressing non-homologous end joining (NHEJ) by disabling DNA-PKcs prevented chemotherapy-induced mutagenesis. Vincristine-induced mutagenesis required p53 and DNA-PKcs but was not affected by ATM status, consistent with it provoking ATM-independent p53-mediated activation of caspases and CAD, which creates DNA lesions in surviving cells that could be mis-repaired by NHEJ. Encouragingly, GDC-0152 failed to stimulate mutations in cells with proficient or defective DNA damage response pathways. This study highlights the elevated oncogenic risk associated with treating DNA repair-deficient patients with genotoxic anti-cancer therapies, and suggests a potential advantage for Smac mimetic drugs over traditional therapies: a reduced risk of therapy-related cancers.

TRAIL causes deletions at the HPRT and TK1 loci of clonogenically competent cells

When chemotherapy and radiotherapy are effective, they function by inducing DNA damage in cancerous cells, which respond by undergoing apoptosis. Some adverse effects can result from collateral destruction of non-cancerous cells, via the same mechanism. Therapy-related cancers, a particularly serious adverse effect of anti-cancer treatments, develop due to oncogenic mutations created in non-cancerous cells by the DNA damaging therapies used to eliminate the original cancer. Physiologically achievable concentrations of direct apoptosis inducing anti-cancer drugs that target Bcl-2 and IAP proteins possess negligible mutagenic activity, however death receptor agonists like TRAIL/Apo2L can provoke mutations in surviving cells, probably via caspase-mediated activation of the nuclease CAD. In this study we compared the types of mutations sustained in the HPRT and TK1 loci of clonogenically competent cells following treatment with TRAIL or the alkylating agent ethyl methanesulfonate (EMS). As expected, the loss-of-function mutations in the HPRT or TK1 loci triggered by exposure to EMS were almost all transitions. In contrast, only a minority of the mutations identified in TRAIL-treated clones lacking HPRT or TK1 activity were substitutions. Almost three quarters of the TRAIL-induced mutations were partial or complete deletions of the HPRT or TK1 genes, consistent with sub-lethal TRAIL treatment provoking double strand breaks, which may be mis-repaired by non-homologous end joining (NHEJ). Mis-repair of double-strand breaks following exposure to chemotherapy drugs has been implicated in the pathogenesis of therapy-related cancers. These data suggest that TRAIL too may provoke oncogenic damage to the genomes of surviving cells.

Infection rates and genotypes of Trypanosoma rangeli and T. cruzi infecting free-ranging Saguinus bicolor (Callitrichidae), a critically endangered primate of the Amazon Rainforest

Parasites of wild primates are important for conservation biology and human health due to their high potential to infect humans. In the Amazon region, non-human primates are commonly infected by Trypanosoma cruzi and T. rangeli, which are also infective to man and several mammals. This is the first survey of trypanosomiasis in a critically endangered species of tamarin, Saguinus bicolor (Callitrichidae), from the Brazilian Amazon Rainforest. Of the 96 free-ranging specimens of S. bicolor examined 45 (46.8%) yielded blood smears positive for trypanosomes. T. rangeli was detected in blood smears of 38 monkeys (39.6%) whereas T. cruzi was never detected. Seven animals (7.3%) presented trypanosomes of the subgenus Megatrypanum. Hemocultures detected 84 positive tamarins (87.5%). Seventy-two of 84 (85.7%) were morphologically diagnosed as T. rangeli and 3 (3.1%) as T. cruzi. Nine tamarins (9.4%) yielded mixed cultures of these two species, which after successive passages generated six cultures exclusively of T. cruzi and two of T. rangeli, with only one culture remaining mixed. Of the 72 cultures positive for T. rangeli, 62 remained as established cultures and were genotyped: 8 were assigned to phylogenetic lineage A (12.9%) and 54 to lineage B (87.1%). Ten established cultures of T. cruzi were genotyped as TCI lineage (100%). Transmission of both trypanosome species, their potential risk to this endangered species and the role of wild primates as reservoirs for trypanosomes infective to humans are discussed.

Field ecology of sylvatic Rhodnius populations (Heteroptera, Triatominae): risk factors for palm tree infestation in western Ecuador

Most Rhodnius species (Triatominae) are primarily associated with palm trees. They maintain enzootic Trypanosoma cruzi transmission and are responsible for human infection (causing Chagas disease) through the Neotropics. Assessing whether individual palm traits (ecological and/or botanical) may increase the risk of palm infestation by triatomines is relevant in areas where bugs invade houses flying from peridomestic palms. We developed a novel fieldwork approach with that objective, and applied it to study infestation by sylvatic Rhodnius ecuadoriensis in 110 tagua palms (Phytelephas aequatorialis). Palm infestation (23% overall) was non-randomly distributed in our sample. Palms located in anthropic landscapes were frequently infested (>27%, n=92), whereas no bugs were collected from palms surveyed within forest remnants (n=18; P=0.01). The presence of abundant decaying vegetable matter (P=0.001) and (to a lesser extent) epiphytic plants (P=0.049) on palm crowns and stems increased the probability of infestation and was positively correlated with the apparent density of bug colonies (R2=0.68). A trend towards higher infestation rates in male palms (34% vs. 18%) could relate to female palm management (removal of infrutescences and vegetable debris) in areas where palm seeds are harvested. An outline of 'risk palm ecotopes' and environmental management-based strategies for the control of peridomestic, palm tree-living vector populations are proposed.

First detection of Leishmania major in peridomestic Phlebotomus papatasi from Isfahan province, Iran: comparison of nested PCR of nuclear ITS ribosomal DNA and semi-nested PCR of minicircle kinetoplast DNA

Two PCR methods were compared for their sensitivity in detecting cultured Leishmania major, before being used to estimate infection rates in female sandflies (Phlebotomus papatasi) collected from peridomestic animal shelters and the nearby burrows of the gerbil reservoir hosts, Rhombomys opimus, in Isfahan province, central Iran. A semi-nested PCR was used to amplify a fragment of minicircle kinetoplast (k) DNA with a length and sequence diagnostic for L. major, and a nested PCR was developed to amplify a fragment containing the internal transcribed spacers of the ribosomal RNA genes (ITS-rDNA) with a sequence diagnostic for L. major. The semi-nested PCR was less sensitive than the nested PCR when using DNA extracted from cultured promastigotes of L. major, but it was more sensitive for detecting L. major in wild-caught sandflies. At the edges of two Isfahan villages, infection rates were significantly higher in P.papatasi collected outside gerbil burrows (14/28) compared with those from peridomestic animal shelters (2/21). This is the first record of L. major detected in P.papatasi from peridomestic sites in Isfahan province.

Leishmania donovanicomplex: genotyping with the ribosomal internal transcribed spacer and the mini-exon

Intergenic region typing by restriction analysis of the ribosomal internal transcribed spacer (ITS) and mini-exon provide diagnostic markers for someLeishmania. Here, we evaluate restriction analysis of these targets for genotyping and phylogenetic analysis within theLeishmania donovanicomplex (agents of visceral leishmaniasis). Each method was useful for genotyping of bothL. donovanicomplex strains and Old WorldLeishmaniaspecies. The targets produced less robust groups than gp63 intergenic regions, but support the need for re-evaluation of the taxonomy of theL. donovanicomplex.

Cognitive impairment in children with hemoglobin SS sickle cell disease: relationship to MR imaging findings and hematocrit

BACKGROUND AND PURPOSE

Children with hemoglobin SS sickle cell disease are known to suffer cognitive impairment if they have silent infarct, but recent evidence suggests that patients with hemoglobin SS sickle cell disease may be impaired even if they are free of infarction. We test a hypothesis that cognitive impairment in children with hemoglobin SS sickle cell disease is associated with low hematocrit and MR imaging abnormalities.

METHODS

A cohort of 49 patients was examined, all of whom had hemoglobin SS sickle cell disease but no history of clinical stroke. The Wechsler scales, which are standardized and age-adjusted, were used to assess cognitive function. Patients also underwent MR imaging examination of the brain, and hematocrit was measured in a subset of 45 patients. MR images were evaluated by at least two readers, and abnormal imaging findings were evaluated by at least three readers. Any lesion was sufficient to be classified as abnormal, with lesions defined to include lacunar infarction, encephalomalacia, or leukoencephalopathy. Hematocrit data were used if obtained within 3 months of psychometric testing and if there were no confounding events in the patients' charts. Wechsler test scores were then evaluated in relation to imaging findings and hematocrit values.

RESULTS

Patients with imaging abnormalities had more cognitive impairment than did patients with normal imaging findings in verbal intelligence quotient (P <.02) and verbal comprehension (P <.01). Patients with low hematocrit had cognitive impairment shown by many performance measures, including full-scale intelligence quotient (P <.006), verbal comprehension (P <.006), and freedom from distractibility (P <.02). Multivariate analysis showed that MR imaging and hematocrit were independent predictors of full-scale intelligence quotient.

CONCLUSION

Focal brain injury, revealed by MR imaging, is associated with cognitive impairment, but our data suggest that diffuse brain injury may also contribute to impairment. These findings show that impairment is multifactorial and suggest that chronic brain hypoxia is part of the pathophysiology of sickle cell disease.

Acute effects of irradiation on cognition: changes in attention on a computerized continuous performance test during radiotherapy in pediatric patients with localized primary brain tumors

PURPOSE

To assess sustained attention, impulsivity, and reaction time during radiotherapy (RT) for pediatric patients with localized primary brain tumors.

METHODS AND MATERIALS

Thirty-nine patients (median age 12.3 years, range 5.9-22.9) with primary brain tumors were evaluated prospectively using the computerized Conners' continuous performance test (CPT) before and during conformal RT (CRT). The data were modeled to assess the longitudinal changes in the CPT scores and the effects of clinical variables on these changes during the first 50 days after the initiation of CRT.

RESULTS

The CPT scores exhibited an increasing trend for errors of omission (inattentiveness), decreasing trend for errors of commission (impulsivity), and slower reaction times. However, none of the changes were statistically significant. The overall index, which is an algorithm-based weighted sum of the CPT scores, remained within the range of normal throughout treatment. Older patients (age >12 years) were more attentive (p < 0.0005), less impulsive (p < 0.07), and had faster reaction times (p < 0.001) at baseline than the younger patients. The reaction time was significantly reduced during treatment for the older patients and lengthened significantly for the younger patients (p < 0.04). Patients with a shunted hydrocephalus (p < 0.02), seizure history (p < 0.0006), and residual tumor (p < 0.02) were significantly more impulsive. Nonshunted patients (p < 0.0001), those with more extensive resection (p < 0.0001), and patients with ependymoma (p < 0.006) had slower initial reaction times.

CONCLUSION

Children with brain tumors have problems with sustained attention and reaction time resulting from the tumor and therapeutic interventions before RT. The reaction time slowed during treatment for patients <12 years old. RT, as administered in the trial from which these data were derived, has limited acute effects on changes in the CPT scores measuring attention, impulsiveness, and reaction time.

Nuclear rDNA ITS-2 sequences reveal polyphyly of Panstrongylus species (Hemiptera: Reduviidae: Triatominae), vectors of Trypanosoma cruzi

Panstrongylus species are widely distributed throughout the Americas, where they act as vectors of Trypanosoma cruzi, agent of Chagas disease. Their intraspecific relationships, taxonomic position and phylogeny in relation to other Triatomini were explored using ribosomal DNA (rDNA) internal transcribed spacer 2 (ITS-2) sequence polymorphisms and maximum parsimony, distance and maximum likelihood analyses of 10 populations representing six species of the genus (P. megistus, P. geniculatus, P. rufotuberculatus, P. lignarius, P. herreri and P. chinai). At the subspecific level, P. megistus appeared more homogeneous than P. rufotuberculatus and P. geniculatus (both with broader distribution). Several dinucleotide microsatellites were detected in the sequences of given species. Many of these microsatellites (GC, TA, GT and AT) showed different number of repeats in different populations and thus, may be very useful for population differentiation and dynamics analyses in future studies. The sequences of P. lignarius (considered sylvatic) and P. herreri (a major disease vector in Peru) were identical, suggesting that these species should be synonymised. Intrageneric analysis showed a clear separation of P. rufotuberculatus, with closest relationships between P. geniculatus and P. chinai, and P. megistus occupying a separate branch. Genetic distances between Panstrongylus species (0.11585-0.22131) were higher than those between Panstrongylus and other Triatomini (16 species from central and North America and South America) (0.08617-0.11039). The distance between P. megistus and P. lignarius/herreri (0.22131) was the largest so far recorded in the tribe. The pronounced differences in length and nucleotide composition suggest a relatively old divergence of Panstrongylus species. P. rufotuberculatus was closer to Mesoamerican Triatoma, Meccus and Dipetalogaster species than to other Panstrongylus. All Panstrongylus clustered with the Mesoamerican clade; P. rufotuberculatus clustered with the phyllosoma complex and T. dimidiata, with D. maxima and T. barberi in a basal position. The rest of Panstrongylus appeared paraphyletically in the tree. This is evidence suggesting polyphyly within the genus Panstrongylus, whose species may be related to the ancestors giving rise to central and North American Triatomini.

A new species of Triatominae from Tamil Nadu, India

A new species of the genus Linshcosteus Distant, 1904 (Hemiptera: Reduviidae: Triatominae) is described from specimens collected near Kalakkadu, Tamil Nadu state, southern India. Specimens were found in deep crevices between rocks, in a region of semi-arid scrub jungle. The distinctiveness of the new species was demonstrated by a morphometric analysis including the five previously described species of Linshcosteus, all from India. Nine measurements of the head were used in an isometric size-free principal component analysis. In terms of discrete morphology the new species, Linshcosteus karupus sp.n. Galvão, Patterson, Rocha & Jurberg differs from the most similar one, L. kali Lent & Wygodzinsky, 1979, by its very prominent anterolateral projections of the pronotum, by the length to width ratio of the pronotum, by the pilosity of the head and several other characters, including phallic structures. A revised key is presented for the six species of the genus.

Kindergarten readiness skills in children with sickle cell disease: evidence of early neurocognitive damage?

Young children with sickle cell disease are at risk of brain damage, including stroke. We tested the hypothesis that such patients are also at risk of cognitive impairment. We characterized the cognitive ability of kindergarten children to minimize the effect of disease-related school absence. The Memphis City Schools use the Developing Skills Checklist, a teacher-administered test given in the classroom, to assess kindergarten-appropriate skills. Data were obtained for 34 patients, who were matched to controls by gender, race, date of birth, school, and approximate income. Two controls were selected for each patient, and paired t-tests were used to compare patient's scores to composite control scores. Patients scored lower than controls in auditory discrimination (P < .01), and there was a trend (P < .10) toward lower patient scores in language. Deficits cannot be attributed to school absence and may predict academic problems for patients with sickle cell disease.

Population morphometric analysis of the tropicopolitan bug Triatoma rubrofasciata and relationships with old world species of Triatoma: evidence of New World ancestry

Quantitative analysis of morphological characters of the head was used to reconstruct the evolutionary history of the tropicopolitan bug Triatoma rubrofasciata (De Geer) (Hemiptera: Reduviidae) and seven species of Old World Triatoma. Multivariate analysis demonstrates that T. rubrofasciata and the Old World species have a high degree of similarity with Nearctic Triatoma species, particularly T. rubida (Uhler). We interpret this to imply a common ancestry for these groups. Dissemination of T. rubrofasciata and subsequent derivation of the Old World species of Triatoma is deduced to have occurred over a period of not more than 350 years.

Immunological selection for Leishmania (Viannia) braziliensis antigens

Comparative ELISA and selective immunoblotting procedures were used in attempts to identify differential serological indicators of infection with the Leishmania (Viannia) braziliensis complex, infection with the L. braziliensis species, and therapeutic cure of localized or mucocutaneous leishmaniasis (LCL or MCL). Although mean ELISA absorbance values were significantly higher for MCL sera than for LCL sera, absorbance could not be used as a reliable indicator of the clinical form of disease. Immunoblotting profiles were similar with sera from MCL and LCL. Pre-adsorption with heterologous trypanosomatid antigens indicated that recognition of antigens of about 56, 60, 66, 72, 88 and 110 kDa might be specific to the subgenus Viannia. In two-colour, sequential, dual ELISA-based immunoblotting, no antigens recognized only by sera from MCL patients were detected. After glucantime therapy, immunoblotting profiles with LCL sera were reduced both in intensity and in the range of antigens detected; a 104-kDa antigen was newly detected with post-treatment LCL sera. Overall, the results show the value of differential immunological detection strategies and support the close relationship between species of the subgenus Viannia but fail to indicate a prognostic antigen for MCL.

Biogeography of Triatominae (Hemiptera: Reduviidae) in Ecuador: implications for the design of control strategies

Chagas disease control strategies strongly depend on the triatomine vector species involved in Trypanosoma cruzi transmission within each area. Here we report the results of the identification of specimens belonging to various species of Triatominae captured in Ecuador (15 species from 17 provinces) and deposited in the entomological collections of the Catholic University of Ecuador (Quito), Instituto Oswaldo Cruz (Brazil), the Natural History Museum London (UK), the London School of Hygiene and Tropical Medicine (UK), the National Institute of Hygiene (Quito), and the Vozandes Hospital (Quito). A critical review of published information and new field records are presented. We analysed these data in relation to the life zones where triatomines occur (11 life zones, excluding those over 2,200 m altitude), and provide biogeographical maps for each species. These records are discussed in terms of epidemiological significance and design of control strategies. Findings relevant to the control of the main vector species are emphasised. Different lines of evidence suggest that Triatoma dimidiata is not native to Ecuador-Peru, and that synanthropic populations of Rhodnius ecuadoriensis in southern Ecuador-northern Peru might be isolated from their sylvatic conspecifics. Local eradication of T. dimidiata and these R. ecuadoriensis populations might therefore be attainable. However, the presence of a wide variety of native species indicates the necessity for a strong longitudinal surveillance system.

On the relationship of P3a and the Novelty-P3

Deviant stimuli give rise to a late positive ERP component with latencies from 250 to 400 ms. Target deviants elicit a P300 with maximum amplitude over parieto-central recording sites while the 'P300' elicited by deviant nontarget stimuli occurs somewhat earlier and shows a more frontally-oriented scalp distribution. Two varieties of frontal P300s have been described, elicited either by rare stimuli (target or nontarget) presented in a two-stimulus oddball task (P3a) or by infrequent, unrecognizable stimuli presented in the context of a three-stimulus oddball task (Novelty-P3). The Novelty-P3 has been observed in a number of subsequent studies; the P3a has not been extensively studied and both its significance and existence have been called into question. The present report describes a replication of two prototypical studies with 'frontal' P3s observed in each context. Application of factor analysis to the two sets of ERP waveforms does not support a distinction between these two components.

Genetic typing and phylogeny of the Leishmania donovani complex by restriction analysis of PCR amplified gp63 intergenic regions

Protozoan parasites of the Leishmania donovani complex (L. donovani, L. infantum/L. chagasi) are causative agents of visceral leishmaniasis. To understand phylogeny and taxonomy within this group better we have developed 2 new polymerase chain reaction-linked restriction fragment length polymorphism (PCR-RFLP) analyses of the major surface protease (msp or gp63) intergenic (ITG) regions. We have named this approach msp intergenic region RFLP typing (MIRT). One intergenic region lies between the constitutive msp (mspC) and stationary phase msp (mspS4) genes (ITG/CS) and the other between multicopy logarithmic phase msp (mspL) genes (ITG/L). The markers generated robust and congruent phylogenies, identifying 5 genetic clusters within L. donovani. One cluster was synonymous with L. infantum (L. chagasi); clusters strongly correlated with isoenzyme typing and some with geographical origin. These genetic groups may be important for epidemiological and clinical studies. The congruence of the groups identified indicates suitability of these genomic targets for taxonomic studies. Furthermore, subgroups of L. donovani were of equivalent phylogenetic status to L. infantum. No evidence was found to support the existence of L. archibaldi. It is likely to be necessary in future to re-evaluate the taxonomic status of L. donovani or of L. infantum, as discrete species.

Leishmania donovani: intraspecific polymorphisms of Sudanese isolates revealed by PCR-based analyses and DNA sequencing

Four polymerase chain reaction (PCR)-based approaches were used to analyze diversity within 23 Sudanese isolates of Leishmania donovani. Methods compared were fingerprinting with single nonspecific primers, restriction analysis of the amplified ribosomal internal transcribed spacer (ITS) locus, single-stranded conformation polymorphism (SSCP), and sequencing of the ITS region. When PCR fingerprinting and restriction analysis of ITS were applied, highly similar fragment patterns were observed for all strains of L. donovani studied. The ITS1 locus gave five different SSCP profiles among the 23 Sudanese isolates, whereas the ITS2 locus was highly conserved with the exception of 1 isolate. Strains of L. donovani derived from other geographical areas were found to have different ITS2 patterns. SSCP analysis correlated well with results of DNA sequencing and confirmed that SSCP was able to detect genetic diversity at the level of a single nucleotide. SSCP had advantages over the other methods employed for investigation of sequence variation within the species L. donovani. There was no correlation between the form of clinical manifestation of the disease and the PCR fingerprinting, ITS-RFLP, or ITS-SSCP characteristics.

Analysis of genetic diversity of Trypanosoma cruzi: an application of riboprinting and gradient gel electrophoresis methods

Analysis of restriction fragment length polymorphism (RFLP) profiles derived from digestion of polymerase chain reaction (PCR) products of the ribosomal 18S from Trypanosoma cruzi yields a typical 'riboprint' profile that can vary intraspecifically. A selection of 21 stocks of T. cruzi and three outgroup taxa: T. rangeli, T. conorhini and Leishmania braziliensis were analysed by riboprinting to assess divergence within and between taxa. T. rangeli, T. conorhini and L. braziliensis could be easily differentiated from each other and from T. cruzi. Phenetic analysis of PCR-RFLP profiles indicated that, with one or two exceptions, stocks of T. cruzi could be broadly partitioned into two groups that formally corresponded to T. cruzi I and T. cruzi II respectively. To test if ribosomal 18S sequences were homogeneous within each taxon, gradient gel electrophoresis methods were employed utilising either chemical or temperature gradients. Upon interpretation of the melting profiles of riboprints and a section of the 18S independently amplified by PCR, there would appear to be at least two divergent 18S types present within T. cruzi. Heterogeneity within copies of the ribosomal 18S within a single genome has therefore been demonstrated and interestingly, this dimorphic arrangement was also present in the outgroup taxa. Presumably the ancestral duplicative event that led to the divergent 18S types preceded that of speciation within this group. These divergent 18S paralogues may have, or had, different functional pressures or rates of molecular evolution. Whether or not these divergent types are equally transcriptionally active throughout the life cycle, remain to be assessed.

Genomic diversity in the Leishmania donovani complex

The Leishmania donovani complex is considered to be composed of 3 species; L. donovani, L. infantum and L. chagasi, although this classification has been challenged. Genotypic relationships within the complex were evaluated at different levels by: binding of the probe Lmet9, specific for L. chagasi and Old World Leishmania spp.; partial sequencing of a constitutive major surface protease single gene (mspC) and random amplification of polymorphic DNA (RAPD). The Old World Leishmania spp. and the L. donovani complex have a monophyletic origin. Leishmania chagasi clearly belongs to the L. donovani complex but it is indistinguishable from L. infantum, which suggests introduction of L. chagasi into the New World in recent history. Leishmania infantum/L. chagasi was identified as a monophyletic group within the L. donovani complex but L. donovani may be paraphyletic. Diversity within L. donovani is substantial and phylogeographical patterns of association were found.

The anti-influenza virus drug rimantadine has trypanocidal activity

We report here that bloodstream forms of the African trypanosome, Trypanosoma brucei, are sensitive to the anti-influenza virus drug rimantadine (50% inhibitory concentration of 1.26 micrograms ml-1 at pH 7.4). The activity is pH dependent and is consistent with a mechanism involving inhibition of the ability to regulate internal pH. Rimantadine is also toxic to the trypanosomatid parasites Trypanosoma cruzi and Leishmania major.

On the molecular taxonomy of Trypanosoma cruzi using riboprinting

In order to investigate the molecular taxonomy within Trypanosoma cruzi, the ribosomal small subunit (18S) gene was amplified by polymerase chain reaction (PCR) from a selection of 21 stocks and 3 outgroup taxa. Amplification products were digested with 10 restriction enzymes; restriction fragments were separated by polyacrylamide gel electrophoresis and profiles were visualized by silver staining. Upon analysis of such riboprint profiles, an estimate of pairwise phenetic distance between stocks of T. cruzi was calculated. Upon principal coordinate analysis of this data matrix, a tendency towards a bi-polar grouping of stocks was observed. These 2 groups were predominantly either zymodeme 1 stocks or zymodeme 2 stocks. The position of zymodeme 3 stocks remained intermediate between the 2 groups but did not form a coherent group by themselves. It would therefore appear premature to warrant division of T. cruzi into 2 discrete taxa or subspecies until the relationships of further zymodeme 3 stocks are elucidated.

Temperature gradient gel electrophoresis (TGGE) analysis of riboprints from Trypanosoma cruzi

To test the homogeneity of 18S sequences within Trypanosoma cruzi, riboprint profiles were separated by temperature gradient gel electrophoresis (TGGE). Upon interpretation of melting curves of fragments within a riboprint profile, there appeared to be two 18S sequence types within each stock examined. Two similar types were also observed within outgroup taxa Trypanosoma conorhini, Trypanosoma rangeli and Leishmania braziliensis. From DNA hybridization studies, these fragments were shown to have homology to the 18S V1 region. There are therefore two 18S V1 regions, differing in sequence, present in all taxa examined. When only a single 18S sequence is used to represent each taxa for phylogenetic inference, comparisons may be between paralogous and not orthologous copies of this region, such that, inferred relationships may merely reflect a gene history. This seriously questions the current molecular phylogeny of these protozoa using 18S data.

Characterisation of a Cryptosporidium parvum-specific cDNA clone and detection of parasite DNA in mucosal scrapings of infected mice

A cDNA library was constructed using total RNA extracted from oocysts and sporozoites of the protozoan parasite Cryptosporidium parvum. The expression library was screened with an anti-C. parvum antiserum and a clone, Cp3.4, with a 2043 bp insert, was extracted. Southern blot analysis demonstrated a single copy gene that was located on a 1.6 Mb chromosome. The gene was found to be C. parvum specific as Cp3.4 did not cross-hybridise with chromosomal DNA from three other apicomplexan parasites. The cDNA encodes a polypeptide with a predicted membrane helix at its C-terminal end which is flanked by stretches of acidic amino acids. Overall, the polypeptide has a low isoelectric point (pI) of 3.94. A total of 21 glycine/proline-rich octapeptides were identified which represented variations of a consensus sequence. The function of this protein is yet unknown. Using Cp3.4-specific PCR primers, this C. parvum gene could be amplified from as little as 0.8 pg of purified parasite DNA in a single polymerase chain reaction. Less than 0.1 ng of DNA from the ileum mucosa of immunosuppressed adult mice that had been infected with C. parvum oocysts was required to detect the parasites. In non-immunosuppressed mice that were infected and which did not shed oocysts in numbers detectable by acid-fast staining, parasite development could be detected in 25 ng of total mucosa DNA. This PCR approach may be a valuable technique for the detection of parasite infections in situations where conventional staining methods fail, such as chronic, low-grade infections or the detection of parasites in potential reservoir hosts.

Input and central processing expressed in ERP and heart rate changes to rare target and rare nontarget stimuli

Whether late positive components of event-related potentials (ERPs) parallel changes in heart rate (HR) indicative of attention/orienting to rare stimuli has been debated. In the present study, a three-stimulus design was used, with rare target, rare nontarget, and frequent standard stimuli delivered under identical conditions except that instructions to subjects described the targets to which subjects should respond but did not describe the nontargets. In Experiment 1, stimuli varied among modalities; in Experiment 2, auditory stimuli were employed. Both ERPs and HR were consistent with automatic processing preceding two stages of controlled processing. Rare stimuli evoked larger parietal P300 and initial HR deceleration than standards. Presumably because of load-reducing effects of long interstimulus intervals, targets and nontargets were not distinguished before a late slow wave and a late phase of HR acceleration. Neither rare stimulus elicited a recognizable frontal P3a.

Failure of buparvaquone (Butalex) in the treatment of canine visceral leishmaniosis

Buparvaquone (Butalex), a therapeutic for theileriosis, has been shown to have anti-leishmanial activity in vitro. Seven dogs with symptomatic, parasitologically positive, canine visceral leishmaniosis were treated with Butalex at 5 mg kg(-1) body weight using four doses over 12 days. Two animals showed minor clinical improvement (growth of healthy hair) but all remained parasitologically positive and disease progression was not halted.

Clinical recovery and limited cure in canine visceral leishmaniasis treated with aminosidine (paromomycin)

Three groups of three, six, and 12 dogs with parasitologically proven clinical visceral leishmaniasis (Leishmania chagasi infection) were treated with intramuscular aminosidine sulfate at doses of 20 mg/kg/day for 15 days; 80 mg/kg/day for 20 days, and 40 mg/kg/day for 30 days, respectively. Follow-up was by parasitologic examination of bone marrow and skin, serology using the indirect immunofluorescent antibody test, and clinical examination for signs of visceral leishmaniasis or adverse effects of treatment. In animals treated with 20 mg/kg/day, for 15 days, there was dramatic clinical improvement with disappearance of conjunctivitis, increase in appetite, weight gain, and recovery of normal skin condition and a healthy coat, but parasitologic relapse occurred between 50 and 100 days after initiation of treatment. Adverse effects were seen with treatment with 80 mg/kg/day for 20 days; three dogs died during or just after treatment, two showed temporary recovery, and one showed total clinical and parasitologic cure that was maintained for four years. Although adverse effects and relapses were seen in some dogs treated with 40 mg/kg/day for 30 days, three of 12 dogs showed complete parasitologic and clinical cure that was sustained for at least four years. Aminosidine treatment cannot be recommended as an alternative to the humane destruction of dogs for the control of canine visceral leishmaniasis because ineffective treatment may prolong carrier status or encourage development of drug resistance. This drug may be a therapeutic option if there is no danger of a dog acting as a reservoir of infection. Achievement of clinical recovery and limited cure with aminosidine suggests that further trials would be of value, possibly in combination with other anti-leishmanial drugs and with supportive measures to reduce adverse effects.

Chagas disease in the Amazon Basin: association of Panstrongylus geniculatus (Hemiptera: Reduviidae) with domestic pigs

Just over 100 autochthonous cases of Chagas disease are reported from the Brazilian Amazon Basin. Panstrongylus geniculatus (Latreille) occurs throughout the region and is the known vector of Trypanosoma cruzi, principal zymodeme 3 (Z3) to the armadillo Dasypus novemcinctus. In the small riverine community of Furo do Rio Pau Grande, pigsties adjoining houses were heavily infested with P. geniculatus, which repeatedly attacked local inhabitants. Palm trees in the immediate vicinity were also infested. T. cruzi principal zymodeme 1 (Z1) was isolated from P. geniculatus, domestic pigs, and opossums, but no human infections were detected. The threat of endemic Chagas disease to the Amazon Basin from either domiciliation of local silvatic triatomine species, or from migration of domestic vectors, demands a program of vigilance and plans of action to eliminate household triatomine colonies.

Random amplification of polymorphic DNA as a tool for taxonomic studies of triatomine bugs (Hemiptera: Reduviidae)

Eleven of 27 decameric primers were found to be suitable for random amplification of polymorphic DNA (RAPD) from triatomine bugs on the basis that they produced discrete profiles and distinguished among Panstrongylus megistus (Burmeister), Rhodnius prolixus Stål, and Triatoma infestans (Klug). The legs, or single leg segments, of individual bugs were used as the source of DNA so that the taxonomic value of the bug was conserved. Within the scope of the specimens studied, RAPD profiles allowed assignment to species even when bugs were kept dry for up to 12 mo. Profiles for individuals within a species were not identical. RAPD profiles, with the specimens tested, distinguished among species of 3 pairs considered to be morphologically similar and closely related, namely, Rhodnius ecuadorensis Lent & León and Rhodnius pictipes Stål; Rhodnius nasutus Stål, and Rhodnius neglectus Lent; Rhodnius prolixus Stål and Rhodnius robustus Larrousse. RAPD data conformed with the perceived affinities among these species. RAPD polymorphisms were seen with T. infestans from 3 different localities, but none of the polymorphisms was confined to 1 source. RAPD provided a molecular basis to reassess taxonomic relationships within the Triatomine subfamily. The accurate distinction of triatomine species and of intraspecific bug populations may contribute to elimination of vector-borne Chagas disease from the Americas.

Pfmdr1 Asn1042Asp and Asp1246Tyr polymorphisms, thought to be associated with chloroquine resistance, are present in chloroquine-resistant and -sensitive Brazilian field isolates of Plasmodium falciparum

Parasite resistance to antimalarial drugs, particularly chloroquine, is the most disturbing problem of malaria chemotherapy. There is evidence that the codon 86Tyr polymorphism of the Pfmdr1 gene is associated with chloroquine resistance in West African Plasmodium falciparum. The association of this and four other coding alterations of the Pfmdr1 gene with chloroquine resistance has not been extensively investigated in South American isolates. In this study, we examined 51 Brazilian P. falciparum isolates for the presence or absence of Asn86Tyr, Asn1042Asp, and Asp1246Tyr polymorphisms. While these isolates were all sensitive in vitro to mefloquine, amodiaquine, and quinine, only 2 (4%) were chloroquine-sensitive. The findings reported here provide the first observations of this kind on a large number of field parasite samples from South America. We show that in vitro chloroquine-resistant and -sensitive strains carry the Asn1042Asp and Asp1246Tyr polymorphisms and provide support for earlier suggestions that Asn86Tyr may be rare or absent in South American P. falciparum.

Use of polymerase chain reaction-based single strand conformational polymorphism and denaturing gradient gel electrophoresis methods for detection of sequence variation of ribosomal DNA of Trypanosoma cruzi

Polymerase chain reaction (PCR) was used to amplify the V1 region of the small sub-unit (18S) ribosomal DNA gene from representative strains of Trypanosoma cruzi. In order to screen for sequence variation, amplification products were subsequently analysed by single strand conformational polymorphism (SSCP) and denaturing gradient gel electrophoresis (DGGE) techniques. SSCP could not detect sequence variation within T. cruzi, although electrophoretic profiles were clearly distinct from both Leishmania donovani and Leishmania braziliensis. DGGE could differentiate strains of T. cruzi and it appears that there are at least 2 18S V1 sequences of this multi-gene family within each strain examined, contrasting with Leishmania spp. where only 1 was identified. This is the first application of PCR-linked SSCP and DGGE analysis for differentiating parasitic protozoa.

Overexpression of cruzipain, the major cysteine proteinase of Trypanosoma cruzi, is associated with enhanced metacyclogenesis

Cruzipain, the major cysteine proteinase of Trypanosoma cruzi has been proposed as a target for chemotherapy against Chagas' disease. To investigate the role of cruzipain we transfected T. cruzi epimastigotes with a recombinant cosmid containing approximately 20 tandemly repeated cruzipain genes. Transformed cells had multiple episomal copies of the vector and exhibited considerable overexpression of cruzipain activity. The upregulation was maintained throughout the parasite life-cycle, and electrophoretic detection techniques indicated that overexpression was correlated with correctly processed enzyme. Immunoelectron microscopy demonstrated that cruzipain had the same developmentally regulated subcellular localisation in transformed and non-transformed cells. In the insect epimastigote form, the enzyme was restricted to vesicles of the endosomal/lysosomal system, whereas in the intracellular forms it was also readily detectable on the cell surface. Phenotypic analysis of the transformed parasites showed that they had an enhanced ability to undergo metacyclogenesis and suggested an association between overexpression of cruzipain and increased resistance to the cysteine proteinase inhibitor Cbz-Phe-Phe-CHN2 (where Cbz is benzoyloxycarbonyl). The increased resistance, however, was less than might be expected if cruzipain was the primary target of the inhibitor. Transgenic parasites did not exhibit increased infectivity.

Functional status in depressed patients: the relationship to disease severity and disease resolution

BACKGROUND

We set out to measure the impact of depression and its clinical resolution on patients' functional status.

METHOD

The Work and Social Disability Scale (WSDS), a five-category investigator-rated scale measuring patient functional status, was completed at baseline and study discontinuation in a 56-day, open, uncontrolled study evaluating the safety of a sustained release (SR) formulation of bupropion in 3167 patients at 105 sites. To be included in the study, patients had to be 18 years or older, have a diagnosis of depression, and be considered appropriate for treatment with bupropion SR. The proportion of patients in each WSDS category, for those patients taking more than 7 days of bupropion SR (N = 2915), was assessed at screen and study discontinuation. The percentage of patients with improved WSDS scores at 56 days was also measured for all patients and correlated with patient and treatment characteristics.

RESULTS

Of the patients entering the trial, 61.8% were markedly or severely impaired in their work or social activities, and only 5.4% were mildly or not impaired. At study discontinuation, more than 54% of patients were judged by the investigator to have very much or much improvement in their clinical symptoms. Results on the WSDS correlated with the clinical improvements; only 22.3% were markedly or severely impaired; and 50.0% were mildly or not impaired at study discontinuation. In addition, 63.9% of patients had less work or social disability at the end of the trial than at study entry. Functional status improved more in patients who had not previously been treated for the episode, had more severe depression at study entry, and had a higher dose and duration of treatment with bupropion SR.

CONCLUSION

The results show that depression results in significant impairment in patients' functional status. Functional status improved in patients treated with bupropion SR for up to 56 days. This improvement was highly correlated with improvement in clinical symptoms and was related to patient characteristics at study entry as well as to treatment patterns during the study.

Dissemination of Leishmania (Viannia) braziliensis

Destructive human mucocutaneous leishmaniasis may appear many years after the primary cutaneous infection with Leishmania (Viannia) braziliensis. Hamsters (Mesocricetus auratus) were infected with metacyclic L. braziliensis promastigotes. It was found that secondary metastatic visceral lesions could arise from a primary cutaneous lesion, or secondary cutaneous lesions from a primary visceral lesion. Parasites in the viscera were shown to be viable, multiplying and capable of metastasis to either secondary visceral or cutaneous sites. The finding of an early metastasis in the wall of a small cutaneous vessel indicates that dissemination can occur by the haematogenous route. Slow growing organisms in viscera may thus be a source for late metastasis to mucocutaneous sites or for systemic relapse after immunosuppression.