Spatial Transcriptomic Analysis of Pituitary Corticotroph Tumors

Context

Spatial transcriptomic (ST) analysis of tumors provides a novel approach to studying gene expression along with the localization of tumor cells in their environment to uncover spatial interactions.

Design

We present ST analysis of corticotroph pituitary neuroendocrine tumors (PitNETs) from formalin-fixed, paraffin-embedded tissues. ST data were compared to immunohistochemistry results. Gene expression profiles were reviewed for cluster annotations, and differentially expressed genes were used for pathway analysis.

Results

Seven tumors were used for ST analysis. In situ annotation of tumor tissue was inferred from the gene expression profiles and was in concordance with the annotation made by a pathologist. Furthermore, relative gene expression in the tumor corresponded to common protein staining used in the evaluation of PitNETs, such as reticulin and Ki-67 index. Finally, we identified intratumor heterogeneity; clusters within the same tumor may present with different transcriptomic profiles, unveiling potential intratumor cell variability.

Conclusion

Together, our results provide the first attempt to clarify the spatial cell profile in PitNETs.

Spatial Multiomics Reveal the Role of Wnt Modulator, Dkk2, in Palatogenesis

Multiple genetic and environmental etiologies contribute to the pathogenesis of cleft palate, which constitutes the most common among the inherited disorders of the craniofacial complex. Insights into the molecular mechanisms regulating osteogenic differentiation and patterning in the palate during embryogenesis are limited and needed for the development of innovative diagnostics and cures. This study utilized the Pax9-/- mouse model with a consistent phenotype of cleft secondary palate to investigate the role of Pax9 in the process of palatal osteogenesis. While prior research had identified upregulation of Wnt pathway modulators Dkk1 and Dkk2 in Pax9-/- palate mesenchyme, limitations of spatial resolution and technology restricted a more robust analysis. Here, data from single-nucleus transcriptomics and chromatin accessibility assays validated by in situ highly multiplex targeted single-cell spatial profiling technology suggest a distinct relationship between Pax9+ and osteogenic populations. Loss of Pax9 results in spatially restricted osteogenic domains bounded by Dkk2, which normally interfaces with Pax9 in the mesenchyme. These results suggest that Pax9-dependent Wnt signaling modulators influence osteogenic programming during palate formation, potentially contributing to the observed cleft palate phenotype.

Spatial Transcriptomic Analysis of Pituitary Corticotroph Tumors Unveils Intratumor Heterogeneity

Spatial transcriptomic (ST) analysis of tumors provides a novel approach on studying gene expression along with the localization of tumor cells in their environment to uncover spatial interactions. Herein, we present ST analysis of corticotroph pituitary neuroendocrine tumors (PitNETs) from formalin-fixed, paraffin-embedded (FFPE) tissues. We report that the in situ annotation of tumor tissue can be inferred from the gene expression profiles and is in concordance with the annotation made by a pathologist. Furthermore, relative gene expression in the tumor corresponds to common protein staining used in the evaluation of PitNETs, such as reticulin and Ki-67 index. Finally, we identify intratumor heterogeneity; clusters within the same tumor may present with different secretory capacity and transcriptomic profiles, unveiling potential intratumor cell variability with possible therapeutic interest. Together, our results provide the first attempt to clarify the spatial cell profile in PitNETs.

The need for maternal critical care education, point-of-care ultrasound and critical care echocardiography in obstetric anesthesiologists training

Globally, the increase in medically complex obstetric patients is challenging the educational approach and clinical management of critically ill obstetric patients. This increase in medical complexity calls into question the educational paradigm in which future physicians are trained. Obstetric anesthesiologists, physician experts in the perio-perative planning and management of complex obstetric patients, represent an essential workforce in the strategies to address maternal mortality. Unfortunately, the development of peri-operative medicine and maternal critical care curricula has only received minor attention in most countries. Proposed guidelines and models highlight the existing need for tiered maternity care services in which critical care infrastructure plays a central role in the delivery of high-risk peripartum care. Therefore, the development of maternal critical care models designed to prepare obstetric anesthesiologists for the clinical challenges of a medically complex patient are warranted. Key critical care topics such as advanced ultrasonography, with the inclusion of quantitative echocardiographic assessments into obstetric anesthesiology educational curricula, will serve to better prepare physicians for the realities of an increasingly complex pregnant patient population, and further reinforce the critical care infrastructure detailed in the Levels of Maternal Care consensus. Despite an increasingly complex obstetric patient population, heterogeneity of maternal critical care practices exists across the globe, warranting standardization and further development of proposed curricula.

Cosmetic and personal care product use, urinary levels of parabens and benzophenones, and risk of endometriosis: results from the EndEA study

AIM

To explore the relationship of urinary concentrations of different congeners of benzophenones and parabens with the utilization of cosmetics and personal care products (PCPs) and their impact on the risk of endometriosis, and to evaluate the influence of oxidative stress on associations found.

METHODS

This case-control study comprised a subsample of 124 women (35 cases; 89 controls). Endometriosis was confirmed (cases) or ruled out (controls) by laparoscopy, with visual inspection of the pelvis and biopsy of suspected lesions (histological diagnosis). Urinary concentrations of benzophenone-1 (BP-1), benzophenone-3 (BP-3), 4-hydroxibenzophenone (4-OH-BP), methyl- (MeP), ethyl- (EtP), propyl- (PrP), and butyl-paraben (BuP), and biomarkers of oxidative stress [lipid peroxidation (TBARS) and total antioxidant power (TAP)] were quantified. Information was gathered on the frequency of use of cosmetics and PCPs. Associations between the frequency of cosmetics/PCP use, urinary concentrations of benzophenones and parabens, oxidative stress, and endometriosis risk were explored in logistic and linear multivariable regression analyses.

RESULTS

The frequency of utilization of certain cosmetics and PCPs was significantly associated with urinary concentrations of benzophenones and parabens. After adjustment for potential confounders, the risk of endometriosis was increased in women in the second versus first terciles of MeP (OR = 5.63; p-value<0.001), BP-1 (OR = 5.12; p-value = 0.011), BP-3 (OR = 4.98; p-value = 0.008), and ƩBPs (OR = 3.34; p-value = 0.032). A close-to-significant relationship was observed between TBARS concentrations and increased endometriosis risk (OR = 1.60, p-value = 0.070) and an inverse association between TAP concentrations and this risk (OR = 0.15; p-value = 0.048). Oxidative stress results did not modify associations observed between benzophenone/paraben exposure and endometriosis risk.

CONCLUSIONS

Our findings indicate that the frequency of cosmetics and PCP utilization is a strong predictor of exposure to certain benzophenone and paraben congeners. These compounds may increase the risk of endometriosis in an oxidative stress-independent manner. Further studies are warranted to corroborate these findings.

Neighborhood disparities in stroke and socioeconomic, urban-rural factors using stroke registry

Introduction

Despite major improvements in management over recent decades, stroke remains a devastating disease in Europe and geographic disparities persist. Determining the spatial distribution of stroke may be useful for both epidemiological research and health services planning. The aim of this study was to estimate stroke incidence rates in Pays de Brest (Western France) and to explore the presence of geographic clusters associated with socioeconomic and urban-rural characteristics.

Methods

The study included incidence stroke cases aged 60 years and more from the Stroke Brest registry for the period 2008 to 2013 aggregated at the census block level. Poisson and negative binomial regression models were used to explore determinants of disease risk. Geographically weighted regression (GWR) was used to allow estimation of local regression coefficients.

Results

Between 2008 and 2013, 3088 cases aged 60 years were identified in Pays de Brest. The incidence of stroke was 6.67 per 1 000 inhabitants. Living in a rural neighborhood with a higher level of blue collar and of farmer was associated with higher age adjusted stroke incidence rate ratio (IRR) 1.23, [95%CI 1.09-1.39]. Higher risk was also found in a city center neighborhood with a higher level of blue [IRR 1.22, 95%CI 1.04-1.49]. Local Poisson GWR models achieved the best fit and suggested evidence of spatially varying regression coefficients and clusters of higher incidence.

Conclusions

Our study contributes to a better understanding of the relationship between stroke risks and contextual characteristics such as socioeconomic circumstances and urban rural setting. This will help targeting areas for specific public health prevention.

Key messages

Variations of stroke were marked according to socioeconomic and urban-rural setting of the living area. This study will help targeting areas for specific public health prevention.

Mapping variation in breast cancer screening: Where to intervene?

Introduction

Mammography screening can reduce breast cancer mortality among women aged 50 years and older. Small geographic areas with lower breast cancer screening uptake may reflect gaps in screening efforts. Our objective was to identify the geographic variations of breast cancer screening uptake among women aged 50-74 years in the Lyon Metropole area, France.

Methods

We used spatial regression models within a generalized additive framework to determine the clusters of census blocks with significantly lower risk of breast cancer screening uptake. Census block-level data on breast cancer screening participation rates were calculated for women aged 50-74 years who did a mammography between 2015-2016 after being invited with a letter by the cancer screening organization. Using smoothed risk maps adjusting for covariates, we estimated the impact of the spatial distribution of deprivation index, part of opportunistic screening on breast cancer screening participation.

Results

Between 2015 and 2016, the participation rate of organized breast cancer screening was 49.9%. As hypothesized, women living in highly deprived census blocks had lower participation rates compared to less deprived. However, women living in rural areas with fewer certified mammography services than in urban areas had the highest participation rate. Spatial analyses identified four clusters, one located in an urban area and three in suburban areas.

Conclusions

Our analysis indicates that depending on the location of the cluster, the influence came from different variables. Knowing the impact of site-specific risk factors is important for implementing an appropriate prevention intervention.

Key messages

Spatial analysis for cancer screening can help to improve health initiatives. This study contributes to a better understanding of the cluster-specific factors that explain geographic disparities.

Increase in pertussis cases along with high prevalence of two emerging genotypes of Bordetella pertussis in Perú, 2012

Background

As has occurred in many regions worldwide, in 2012 the incidence of pertussis increased in Perú. This epidemiologic situation has been associated with a waning vaccine-induced immunity and the adaptation of Bordetella pertussis to vaccine-induced immunity along with improved diagnostic methods.

Methods

The study comprised a total of 840 pertussis-suspected cases reported in Perú during 2012. We summarize here the distribution of pertussis cases according to age and immunization status along with the immunization-coverage rate. Laboratory diagnosis was performed by culture test and real-time polymerase-chain reaction (PCR). B. pertussis bacteria recovered from infected patients were characterized by pulsed-field gel electrophoresis (PFGE), and the DNA sequencing of the pertussis-toxin (promoter and subunit A), pertactin, and fimbriae (fim2 and fim3) genes.

Results

From the total pertussis-suspected cases, 191 (22.7 %) infections were confirmed by real-time PCR and 18 through cultivation of B. pertussis (2.1 %), while one infection of B. parapertussis (0.11 %) was also detected by culture. Pertussis was significantly higher in patients that had had 0–3 vaccine doses (pentavalent vaccine alone) than in those who had had 4–5 vaccine doses (pentavalent plus DwPT boosters) at 94.3 vs. 5.7 %, respectively (p < 0.00001). The relative risk (RR) for patients with 4–5 doses compared to those with fewer than 4 doses or no dose was 0.23 (95 % Confidence Interval: 0.11–0.44), while the vaccine effectiveness was 77 % and coverage 50.5 %. Genetic analysis of B. pertussis isolates from different Peruvian regions detected two clonal groups as identified by PFGE. Those two groups corresponded to the B. pertussis genotypes emerging worldwide ptxP3-ptxA1-prn2 or 9-fim3-1 and ptxP3-ptxA1-prn2 or 9-fim3-2.

Conclusions

Two emerging B. pertussis genotypes similar to isolates involved in worldwide epidemics were detected in Perú. Low vaccine coverage (<50 %) and genetic divergence between the vaccine-producing strain and the local isolates could contribute to this pertussal epidemic.

Improved upper limits on the stochastic gravitational-wave background from 2009-2010 LIGO and Virgo data

Gravitational waves from a variety of sources are predicted to superpose to create a stochastic background. This background is expected to contain unique information from throughout the history of the Universe that is unavailable through standard electromagnetic observations, making its study of fundamental importance to understanding the evolution of the Universe. We carry out a search for the stochastic background with the latest data from the LIGO and Virgo detectors. Consistent with predictions from most stochastic gravitational-wave background models, the data display no evidence of a stochastic gravitational-wave signal. Assuming a gravitational-wave spectrum of Ω_{GW}(f)=Ω_{α}(f/f_{ref})^{α}, we place 95% confidence level upper limits on the energy density of the background in each of four frequency bands spanning 41.5-1726 Hz. In the frequency band of 41.5-169.25 Hz for a spectral index of α=0, we constrain the energy density of the stochastic background to be Ω_{GW}(f)<5.6×10^{-6}. For the 600-1000 Hz band, Ω_{GW}(f)<0.14(f/900  Hz)^{3}, a factor of 2.5 lower than the best previously reported upper limits. We find Ω_{GW}(f)<1.8×10^{-4} using a spectral index of zero for 170-600 Hz and Ω_{GW}(f)<1.0(f/1300  Hz)^{3} for 1000-1726 Hz, bands in which no previous direct limits have been placed. The limits in these four bands are the lowest direct measurements to date on the stochastic background. We discuss the implications of these results in light of the recent claim by the BICEP2 experiment of the possible evidence for inflationary gravitational waves.

Search for gravitational waves associated with γ-ray bursts detected by the interplanetary network

We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(-2)M⊙c(2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.

Search for gravitational waves associated with γ-ray bursts detected by the interplanetary network

We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(-2)M⊙c(2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.

Constraints on cosmic strings from the LIGO-Virgo gravitational-wave detectors

Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs from cosmic microwave background measurements and pulsar timing data. In particular, if the size of loops is given by the gravitational backreaction scale, we place upper limits on the string tension Gμ below 10(-8) in some regions of the cosmic string parameter space.

[Age and growth of the hybrid tilapia Oreochromis niloticus x Oreochromis aureus (Perciformes: Cichlidae) in the dam "Zimapan" Mexico]

Studies on age and growth in fishes are essential to establish models on population dynamics. The previous issues were determined in this study by scale growth analyses. Between September 2003 and May 2004, 382 organisms were captured using gill and atarraya nets. Eight samples were developed every month a long this study. Standard length in centimeters (L(e)), total weight in grams (P9t)), scale length in centimeters (L(esc)) and growth rings were determined. The size and weight ranged from 38 to 232 mm (L(e)) and 8.7 to 311.9 g (P(t)), respectively. The growth rings analyses reveal four age groups, being the second group the most representative with 34.3% of the total sampled. The scale ring analyses showed two growth rings, one develops between November-January and the other between April-May, in good correlation with low temperature and gonad development, respectively. The growth parameters were established as: L infinity = 281.1mm, W infinity = 877.1g, K = 0.33 and T(0) = 0.88 year(-1). The growth curves based on length and weight were described by using the von Bertalanffy model: L(e) = 28.11[1 -e (-0.33(t+0.88))] and P(t) = 877.17[1-e (-0.33(t+0.88))]3. Finally, it is concluded that commercial catches in this dam are between a year and year and half-old when exploited.

Periodontal pathogens in atheromatous plaques isolated from patients with chronic periodontitis

BACKGROUND AND OBJECTIVE

It has been suggested that chronic infections may predispose to cardiovascular disease. The relationship between periodontal disease and cardiovascular disease has been a subject of increasing research in recent years. The isolation and identification of periodontal bacteria from atheromatous plaque can contribute to our knowledge of this vascular disease. The aim of this study was to isolate and identify periodontal bacteria from the periodontal pockets of different patients and to compare them with the microorganisms detected in the atheromatous plaques obtained from the same patients.

MATERIAL AND METHODS

Clinical isolates were obtained from 12 patients with periodontal wounds and atheromathous plaques. These samples were cultured in the appropriate bacteriological culture media and incubated in an anaerobic system. Periodontal bacteria were identified using polymerase chain reaction (PCR) assays.

RESULTS

From the 12 patients studied, nine presented different periodontopathic bacterial species. In two, Actinobacillus actinomycetemcomitans was present in the periodontal pockets and the respective atheromatous plaques.

CONCLUSION

The presence of A. actinomycetemcomitans in atheromatous plaques and the periodontal pockets of the same patients could indicate a role for periodontal pathogenic bacteria in the atherosclerosis disease process.

Plasmid-mediated bacteriocin production by Shigella flexneri isolated from dysenteric diarrhoea and their transformation into Escherichia coli

AIMS

To determine the production of bacteriocin by Shigella flexneri strains, to relate their production to the presence of dysenteric diarrhoea and to asses the genetic determination of the bacteriocin.

METHODS AND RESULTS

One hundred and sixteen strains of Sh. flexneri were isolated from patients with diarrhoea and 49 of them produced bacteriocin active against several Escherichia coli and abacteriocinogenic Sh. flexneri strains. The extrachromosomal DNA isolated from bacteriocinogenic Sh. flexneri strains were used as a substrate to transform E. coli HB-101 cells by means of electroporation.

CONCLUSIONS

Only the Sh. flexneri strains isolated from dysenteric diarrhoea produced bacteriocin. It was demonstrated that a plasmid of approx. 3 kb was responsible for the genetic determination of these anti-bacterial substances.

SIGNIFICANCE AND IMPACT OF THE STUDY

A 3-kb plasmid that harboured information for the production of bacteriocin by Sh. flexneri strains was described. The production of this bacteriocin may be related to dysenteric diarrhoea produced by these bacterial strains.

In vitro antibacterial activity of the peptide PsVP-10 against Streptococcus mutans and Streptococcus sobrinus with and without glycocalyx

The antibacterial activity of the peptide PsVP-10 obtained from Pseudomonas sp. R10 against Streptococcus mutans and Streptococcus sobrinus was investigated. One hundred and twenty strains of S. mutans and 120 strains of S. sobrinus with and without glycocalyx were isolated from saliva samples in trypticase-yeast-cysteine-sucrose-bacitracin (TYCSB) agar. Bacterial identification was made by polymerase chain reaction. Glycocalyx production was observed in modified TYCSB agar and confirmed with a modified version of the microplate adherence assay. The minimum inhibitory concentration (MIC) of PsVP-10 bacteriocin was determined by means of the agar dilution method, and the time of bacterial death was calculated by means of colony-forming unit counts. The MIC of the bacteriocin PsVP-10 for both bacterial species with and without glycocalyx was < 2 mg/L and the time of bacterial death was less than 240 s for all the studied bacterial strains. Thus, bacteriocin PsVP-10 could be an interesting possibility to combat these cariogenic bacterial species.

NeuroD1 in the endocrine pancreas: Localization and dual function as an activator and repressor

The basic helix-loop-helix transcription factor NeuroD1 regulates cell fate in the nervous system but previously has not been considered to function similarly in the endocrine pancreas due to its reported expression in all islet cell types in the newborn mouse. Because we found that NeuroD1 potently represses somatostatin expression in vitro, its pattern of expression was examined in both strains of mice in which lacZ has been introduced into the NeuroD1 locus by homologous recombination. Analysis of adult transgenic mice revealed that NeuroD1 is predominantly expressed in beta-cells and either absent or expressed below the limit of lacZ detection in mature alpha-, delta-, or PP cells. Consistent with a previous report, NeuroD1 colocalizes with glucagon as well as insulin in immature islets of the newborn mouse. However, no colocalization of NeuroD1with somatostatin was detected in the newborn. In vitro, ectopic expression of NeuroD1 in TRM-6/PDX-1, a human pancreatic delta-cell line, resulted in potent repression of somatostatin concomitant with induction of the beta-cell hormones insulin and islet amyloid polypeptide. Additionally, NeuroD1 induced expression of Nkx2.2, a transcription factor expressed in beta- but not delta-cells. Transfection studies using insulin and somatostatin promoters confirm the ability of NeuroD1 to act as both a transcriptional repressor and activator in the same cell, suggesting a more complex role for NeuroD1 in the establishment and/or maintenance of mature endocrine cells than has been recognized previously.

Limits for the central production of Theta+ and Xi(--)pentaquarks in 920-GeV pA collisions

We have searched for Theta+(1540) and Xi(--)(1862) pentaquark candidates in proton-induced reactions on C, Ti, and W targets at midrapidity and square root of s = 41.6 GeV. In 2 x 10(8) inelastic events we find no evidence for narrow (sigma approximately 5 MeV) signals in the Theta+ --> pK0(S) and Xi(--) --> Xi- pi- channels; our 95% C.L. upper limits (UL) for the inclusive production cross section times branching fraction B dsigma/dy/(y approximately 0) are (4-16) mub/N for a Theta+ mass between 1521 and 1555 MeV, and 2.5 mub/N for the Xi(--). The UL of the yield ratio of Theta+/Lambda(1520) < (3-12)% is significantly lower than model predictions. Our UL of B Xi(--)/Xi(1530)0 < 4% is at variance with the results that have provided the first evidence for the Xi(--).

In vitro antibacterial activity of the peptide PsVP-10 against antimicrobial-resistant Enterococcus faecalis isolated from clinical samples

OBJECTIVE

To analyse the antimicrobial activity of the peptide PsVP-10 against 67 resistant Enterococcus faecalis strains isolated from clinical samples.

METHODS

The qualitative disc diffusion method and MIC determinations were used.

RESULTS

The presence of several multidrug-resistant phenotypes of E. faecalis was demonstrated, in which there were high MICs to chloramphenicol, tetracycline, vancomycin, cefaloridine, ampicillin and gentamicin. In comparison, the peptide PsVP-10 showed lower MICs against all the multidrug-resistant and susceptible E. faecalis.

CONCLUSIONS

There is an urgent need for the development of novel antimicrobial agents against the highly resistant E. faecalis. The present study shows that the peptide PsVP-10 might make a contribution to the solution of this serious problem.

Genes coding structural proteins in the Leishmania braziliensis complex

Acidic ribosomal P1 and P2b proteins, referred to as P proteins, and histone H3 are reported for first time in the Leishmania braziliensis complex. Deoxyribonucleic acid analysis and multiple sequence alignment suggest that both P proteins may maintain their structural function in the ribosomal stalk, in spite of the high rate of mutations detected. The deduced amino acid sequence of protein P1 showed 51% identity with Trypanosoma cruzi protein P1 and protein P2b showed 61% identity with T. cruzi protein P2b. Another conserved protein, L. (Viannia) braziliensis histone H3, showed 82% and 70% identity with histone H3 of L. (Leishmania) infantum and T. cruzi, respectively. The N-terminal end of this histone is divergent in comparison with the consensus eukaryotic sequence. Their predicted tridimensional structure was designed.

Production of antimicrobial substances, by hospital bacteria, active against other micro-organisms

Fifty-nine clinical strains of bacteria, isolated from patients in the Regional Hospital of Talca, were studied. Seventy-four percent of these strains produced antibacterial substances, in comparison with 18% of the same bacterial species obtained from patients from a non-hospital habitat. Almost all the bacteria isolated from hospitalized patients demonstrated in vitro resistance to different antimicrobial agents. Pseudomonas aeruginosa was the most frequent species producing antibacterial substances and its products were of high potency, with a wide spectrum of antimicrobial activity. Cure of plasmid DNA, in most of the antibacterial-producer strains, resulted in the loss of their lethal activity and they also became susceptible in vitro to anti-microbials. These results indicated that such properties are encoded in extrachromosomal DNA. We believe that the knowledge of the antimicrobial activity and resistance to antimicrobials of bacteria from a hospital habitat can help explain the selection and persistence of such strains in this particular ecological niche.

Short regimen of praziquantel in the treatment of single brain enhancing lesions

Twenty-six patients with single enhancing brain lesion (SEL) were openly assigned to receive single-day praziquantel therapy (n=14), or not (n=12). From 14 treated patients, complete resolution was found in 11, partial resolution in two, and the remaining case was later diagnosed as an arteriovenous malformation. Side effects presented in only one patient and remitted in the same day with symptomatic treatment. Conversely, the lesions persisted unchanged in six of 12 patients in the non-treatment group. Untreated patients with persisting lesions were prescribed praziquantel treatment. After this, SELs disappeared in three cases, other diagnoses (brain tuberculoma and arteriovenous malformation) were made in two, and one was not evaluated. When analyzed in regard to the baseline serology, resolution of lesions on computed tomography was found in 13 (complete=12, partial=1) of 14 seropositive patients, whereas it only happened in six (complete=5, partial=1) of 12 seronegative patients. Serological screening defines a subset of SEL patients with good prognosis. If antiparasitic therapy is to be used in patients with SEL, and we cannot find a strong argument against it, single-day praziquantel is the regimen of choice based on duration, costs, and minimal side effects.

Modulation of human polymorphonuclear leukocyte adherence by cyanopeptide toxins

The oligopeptides microcystins and nodularins are the most common and abundant cyanotoxins present in diverse water systems. They cause different illnesses in animal and humans, sometimes leading to death, and are responsible for severe environmental problems. Here we demonstrate that both microcystin-LR and N. spumigena nodularin (Nod) significantly enhance the early spontaneous adherence of peripheral polymorphonuclear leukocytes (PMNs) over the concentration range 10(-11)-10(-9) M. However, neither of them affect significantly the late spontaneous adherence or the early or late PMN-stimulated adherence (when cells are treated with formyl-methionyl-leucyl-phenylalanine). Since PMN adherence is a key step in the immune response, our data clearly indicate for the first time the immunomodulatory capacity of cyanopeptide toxins. The low concentrations at which the adherence modulation occurs are similar to the physiological concentrations for natural mammalian peptide hormones. Such concentrations are well below those recommended by other authors and World Health Organization in terms of risk assessment as safe for drinking water (8x10(-10) to 10(-9) M).

Acidic ribosomal proteins and histone H3 from Leishmania present a high rate of divergence

Another additional peculiarity in Leishmania will be discussed about of the amino acid divergence rate of three structural proteins: acidic ribosomal P1 and P2b proteins, and histone H3 by using multiple sequence alignment and dendrograms. These structural proteins present a high rate of divergence regarding to their homologous protein in Trypanosoma cruzi. At this regard, L. (V.) peruviana P1 and T. cruzi P1 showed 57.4% of divergence rate. Likewise, L. (V.) braziliensis histone H3 and acidic ribosomal P2 protein exhibited 31.8% and 41.7% respectively of rate of divergence in comparison with their homologous in T. cruzi.

An outbreak of acute bartonellosis (Oroya fever) in the Urubamba region of Peru, 1998

During May 1998, we conducted a case-control study of 357 participants from 60 households during an outbreak of acute bartonellosis in the Urubamba Valley, Peru, a region not previously considered endemic for this disease. Blood and insect specimens were collected and environmental assessments were done. Case-patients (n = 22) were defined by fever, anemia, and intra-erythrocytic coccobacilli seen in thin smears. Most case-patients were children (median age = 6.5 years). Case-patients more frequently reported sand fly bites than individuals of neighboring households (odds ratio [OR] = 5.8, 95% confidence interval [CI] = 1.2-39.2), or members from randomly selected households > or = 5 km away (OR = 8.5, 95% CI = 1.7-57.9). Bartonella bacilliformis isolated from blood was confirmed by nucleotide sequencing (citrate synthase [g/tA], 338 basepairs). Using bacterial isolation (n = 141) as the standard, sensitivity, specificity, and positive predictive value of thin smears were 36%, 96%, and 44%, respectively. Patients with clinical syndromes compatible with bartonellosis should be treated with appropriate antibiotics regardless of thin-smear results.

Molecular basis of glucose-6-phosphate dehydrogenase deficiency among Filipinos

BACKGROUND

Multiplex polymerase chain reaction (PCR) using multiple tandem forward primers and a common reverse primer (MPTP) was recently established as a comprehensive scanning system for mutations in X-linked recessive diseases. In this report, MPTP was tested to scan for mutations of the glucose-6-phosphate dehydrogenase (G6PD) gene.

METHODS

Mutations in exon 11 of the G6PD gene were screened by MPTP in five unrelated Filipino cases with G6PD deficiency.

RESULTS

Of the five patients, four screened positive for a mutation in the gene. Sequencing of the amplified products confirmed that three cases had a C-->T substitution at nucleotide (n.t.) 1360 (C1360T) resulting in an amino acid change of arginine to cysteine at position 454 and one had a silent single base substitution C-->T at nucleotide 1311.

CONCLUSION

Our results document a C1360T mutation of the G6PD gene in three Filipino patients in the Philippines.

Note: purification and characterization of the bacteriocin PsVP-10 produced by Pseudomonas sp

A bacteriocin (bacteriocin PsVP-10) produced by Pseudomonas sp. R-10 was purified by a simple method that included an extraction of the bacteriocin with chloroform, followed by cation exchange chromatography. The purity of the bacteriocin was verified by RP-HPLC. It is a peptide of 2.4 kDa, very stable to heat, to proteolytic enzymes and to pH. It presents a very broad spectrum of antimicrobial activity against Gram-positive and Gram-negative bacteria.

Recombinant antigens for specific and sensitive serodiagnosis of Latin American tegumentary leishmaniasis

The diagnostic potential of recombinant leishmanial antigens for Latin American tegumentary leishmaniasis (LATL) was examined. Two Leishmania (Viannia) peruviana recombinant proteins, T26-U2 and T26-U4, were assessed by their reactivity to detect specific anti-leishmanial antibodies. Seventy-eight individual sera from persons with LATL, 39 from those with other diseases, and 10 negative control sera were tested by Western blotting and enzyme-linked immunosorbent assay. The sensitivity of the test using T26-U2 plus T26-U4 was similar to that obtained with whole parasite extract (92%). However, the specificity obtained using both recombinant antigens (87%) was higher than that of the whole parasite extract (65%). All tests using recombinant proteins (T26-U2, T26-U2 plus T26-U4 or T26-U4) had a higher positive predictive value (89%, 92% and 98%, respectively) than the value obtained using total parasites (81%). Eleven Colombian sera were also tested, and the results indicated that T26-U2 plus T26-U4 could be used successfully in Peru and in other Latin American countries.

The expression of the bstVIM gene from Bacillus stearothermophilus V is restricted to vegetative cell growth

The activity of BstVI DNA methyltransferase was monitored during the sporulative cycle of Bacillus stearothermophilus V. Significant methylase activity was found only in bacteria growing vegetatively. This was confirmed by Northern hybridization, which indicated that the bstVIM gene was not transcribed in cells undergoing sporulation. Supporting evidence came from experiments which demonstrated that the RNA polymerase holoenzyme from these cells did not recognize the promoter elements upstream of the bstVIM gene.

Isolation and characterization of AAP1. A gene encoding an alanine/arginine aminopeptidase in yeast

The yeast AAP1 gene, encoding a putative amino-peptidase, was isolated based on its ability to suppress the temperature-sensitive growth on nonfermentable carbon sources of spr5, a stationary phase regulatory mutant. AAP1 was physically mapped to chromosome VIII between PUT2 and CUP1. Sequence analysis of the AAP1 gene showed a 1581-nucleotide open reading frame capable of encoding a 59-kilodalton protein. The protein encoded by this open reading frame exhibits approximately 40% sequence identity to human, rat, and mouse aminopeptidases. In limited regions, sequence identity between Aap1 and the mammalian aminopeptidases ranges from 53% to 93%. Insertional inactivation of the AAP1 gene resulted in a decrease in glycogen accumulation and the loss of the major band of arginine/alanine aminopeptidase activity. Strains carrying the AAP1 gene on a high copy plasmid show an increase in the major arginine/alanine aminopeptidase activity, a dramatic increase in glycogen accumulation, and an increase in transcription from a vector carrying lacZ fused to the promoter of a gene (SSA3) expressed during post-diauxic and stationary phases of the culture cycle. We conclude that although the AAP1 gene is not essential for viability, the Aap1 protein positively affects glycogen accumulation in yeast.