Correlation of Doppler US tumor signals with neovascular morphologic features

Abnormal Doppler ultrasound signals were detected in 44 of 47 patients with primary malignant tumors of the liver, kidney, adrenal gland, or pancreas (94%). Two different signal types were noted: a high-velocity signal (n = 38) with Doppler shifts exceeding 3 kHz (at an insonating frequency of 3 MHz) and a very low-impedance signal (n = 9) demonstrating little systolic-diastolic variation. In three patients, both types were present. In 19 patients, histologic (n = 12) and/or angiographic (n = 16) correlation was available. Among 13 patients with angiographic studies and signals over 3 kHz, arteriovenous shunting was demonstrated in six. The ratio of the systolic to diastolic Doppler shift is a function of vascular impedance. This systolic/diastolic index was less than 3 in eight patients with histologic correlation. All eight had prominent vascular spaces, and the flow in such thin-walled, endothelium-lined spaces would account for the low-impedance signals. Of nine patients with systolic/diastolic indexes of 3 or less and angiographic correlation, three had marked and four had moderate tumor staining.

Validity and reliability of the SF-36 Health Survey Questionnaire in patients with coronary artery disease

The validity and reliability of the SF-36 has been studied in 185 patients hospitalized with suspected ischemic cardiopathy, classified into four groups (AMI, unstable angina, nonischemic cardiologies, and absence of cardiologies). The validity of the construct has been analyzed by means of the association of the SF-36 with sociodemographic and clinical variables, and with diagnostic groups. The correlation of the subscales with GHQ-28 scores and the factorial structure have been studied. Internal consistency was measured by Cronbach's alpha and the item-internal consistency and item-discriminant validity. The validation result was as expected, although the scores were significantly lower in patients with unstable angina, only in the PF, VT, and GH subscales. The correlations with the GHQ-28 were high for MH and VT. The internal consistency was high (Cronbach's alpha 0.72-0.94). Factorial analysis identified eight factors, with the "anxiety" component of subscale MH remaining as an independent factor. These results suggest that the SF-36 is a useful scale for the differentiated clinical forms of ischemic cardiopathy, with the additional capability of reflecting the level of anxiety in these patients.

Focal liver masses: differential diagnosis with pulsed Doppler US

Duplex Doppler ultrasound (US) was used in 68 consecutive patients with focal liver lesions, including 12 hepatocellular carcinomas, one cholangiocarcinoma, 37 metastases, 15 hemangiomas, one hemangioendothelioma, and two focal nodular hyperplasias. Of the hepatocellular carcinomas, six were diffusely hyperechoic, two were hypoechoic, two were single hyperechoic lesions, and two were multifocal and hyperechoic. All ten tumors with Doppler shifts of 5 kHz or above proved to be hepatocellular carcinomas. The other two hepatocellular carcinomas showed Doppler shifts of 3 kHz. In contrast, no hemangioma showed shifts above 0.7 kHz, and ten of the 15 gave no detectable signal. Of the metastases, 20 gave no signal and 17 had signals of up to 4 kHz. Three-kilohertz signals were also obtained from a cholangiocarcinoma, a hemangioendothelioma, and focal nodular hyperplasia. Correlation with angiographic findings suggested that the high-velocity Doppler signals were associated with large pressure gradients due to arteriovenous shunting. Duplex Doppler US can therefore aid in the differential diagnosis of diffuse and focal liver lesions.

Heterologous prime-boost vaccination with a non-replicative vaccinia recombinant vector expressing LACK confers protection against canine visceral leishmaniasis with a predominant Th1-specific immune response

Leishmaniasis caused by Leishmania infantum is a severe endemic disease in the Mediterranean basin, being domestic dogs the main reservoir of the disease that plays a key role in the transmission to humans. Studies on vaccines against canine leishmaniasis, aimed to modify the T cell repertoire, have advanced in recent years. LACK vaccination assays, using protein or DNA vectors, show protection against cutaneous L. major infections by redirecting the early IL-4 responses to a protective Th1 response. The aim of this study was to define the effectiveness and type of immune response in a canine visceral leishmaniasis model of two poxvirus vectors (Western reserve strain, WR and modified vaccinia virus Ankara, MVA) expressing the LACK protein of L. infantum in prime/boost vaccination protocols. The results obtained showed that dog vaccination priming with DNA-LACK followed by a booster with MVA-LACK or rVV-LACK triggered a Th1 type of immune response, leading to protection against canine visceral leishmaniasis. This protection correlated with absence of visceral leishmaniasis symptoms, lower Leishmania-specific antibodies, higher degree of T cell activation in Leishmania-target organs and higher synthesis of Th1 cytokines. In addition, we found that dogs boosted with the non-replicative virus show less VL symptoms and higher degree of T cell activation, providing evidences for a clear advantage of MVA-LACK as a vaccination vector against canine visceral leishmaniasis.

Clinical utility of plasma-based digital next-generation sequencing in patients with advance-stage lung adenocarcinomas with insufficient tumor samples for tissue genotyping

BACKGROUND

Approximately 30% of tumor biopsies from patients with advanced-stage lung adenocarcinomas yield insufficient tissue for successful molecular subtyping. We have analyzed the clinical utility of next-generation sequencing (NGS) of cell-free circulating tumor DNA (ctDNA) in patients with inadequate tumor samples for tissue genotyping.

PATIENTS AND METHODS

We conducted the study in a multi-institutional prospective cohort of clinically unselected patients with advanced-stage lung adenocarcinomas with insufficient tissue for EGFR, ALK or ROS1 genotyping across 12 Spanish institutions (n = 93). ctDNA NGS was carried out by Guardant Health (Guardant360, Redwood City, CA), using a hybrid-capture-based 73-gene panel. Variants were deemed actionable if they were part of the OncoKB precision oncology knowledge database and classified in four levels of actionability based on their clinical or preclinical evidence for drug response.

RESULTS

Eighty-three out of 93 patients (89%) had detectable levels of ctDNA. Potentially actionable level 1-4 genomic alterations were detected in 53 cases (57%), of which 13 (14%) had level 1-2A alterations (Food and Drug Administration-approved and standard-care biomarkers according to lung cancer guidelines). Frequencies of each genomic alteration in ctDNA were consistent with those observed in unselected pulmonary adenocarcinomas. The majority of the patients (62%), particularly those with actionable alterations (87%), had more than one pathogenic variant in ctDNA. The median turnaround time to genomic results was 13 days. Twelve patients (13%) received genotype-matched therapies based on ctDNA results, deriving the expected clinical benefit. Patients with co-occurring pathogenic alterations had a significantly shorter median overall survival as compared with patients without co-occurring pathogenic alteration (multivariate hazard ratio = 5.35, P = 0.01).

CONCLUSION

Digital NGS of ctDNA in lung cancers with insufficient tumor samples for tissue sequencing detects actionable variants that frequently co-occur with other potentially clinically relevant genomic alterations, allowing timely initiation of genotype-matched therapies.

Analgesic efficacy of a hydrocodone with ibuprofen combination compared with ibuprofen alone for the treatment of acute postoperative pain

Hydrocodone is a semisynthetic opioid with analgesic and antitussive properties qualitatively similar to other opioid agonists. Ibuprofen is a nonsteroidal antiinflammatory agent with analgesic and antipyretic activity and is an effective, primarily peripheral-acting antiinflammatory analgesic. The objective of this clinical trial was to determine the additive analgesic effect of the combination of 15 mg hydrocodone bitartrate with 400 mg ibuprofen, relative to 400 mg ibuprofen alone and placebo, in the treatment of postoperative pain. The single-dose analgesic efficacy of the combination of hydrocodone bitartrate with ibuprofen was compared with ibuprofen alone and placebo in 120 patients with moderate or severe postoperative pain after abdominal surgery. Analgesia was measured during the 6-hour period after dosing based on onset of relief, hourly and summary variables, and duration of effect. A significantly greater proportion of patients treated with the hydrocodone/ibuprofen combination reported onset of relief compared with ibuprofen or placebo; however, the distribution functions for time to onset of relief did not differ among treatments. Hydrocodone with ibuprofen and ibuprofen alone were significantly more effective than placebo for all measures of analgesia. The combination of hydrocodone with ibuprofen was significantly superior to ibuprofen for all hourly analgesic evaluations, weighted sum of pain intensity differences (SPID), total pain relief (TOTPAR), and global rating of study medication. No patients in the hydrocodone with ibuprofen group required analgesic remedication during the 6-hour study period, compared with 25% and 82% in the ibuprofen and placebo groups, respectively. The analgesic superiority of 15 mg hydrocodone bitartrate combined with 400 mg ibuprofen compared with 400 mg ibuprofen alone was demonstrated across many efficacy variables.

Three dimensional reconstruction by electron microscopy in the life sciences: An introduction for cell and tissue biologists

Early applications of transmission electron microscopy (TEM) in the life sciences have contributed tremendously to our current understanding at the subcellular level. Initially limited to two-dimensional representations of three-dimensional (3D) objects, this approach has revolutionized the fields of cellular and structural biology-being instrumental for determining the fine morpho-functional characterization of most cellular structures. Electron microscopy has progressively evolved towards the development of tools that allow for the 3D characterization of different structures. This was done with the aid of a wide variety of techniques, which have become increasingly diverse and highly sophisticated. We start this review by examining the principles of 3D reconstruction of cells and tissues using classical approaches in TEM, and follow with a discussion of the modern approaches utilizing TEM as well as on new scanning electron microscopy-based techniques. 3D reconstruction techniques from serial sections and (cryo) electron-tomography are examined, and the recent applications of focused ion beam-scanning microscopes and serial-block-face techniques for the 3D reconstruction of large volumes are discussed. Alternative low-cost techniques and more accessible approaches using basic transmission or field emission scanning electron microscopes are also examined.

Pain in multiple sclerosis: a systematic review of neuroimaging studies

Introduction

While pain in multiple sclerosis (MS) is common, in many cases the precise mechanisms are unclear. Neuroimaging studies could have a valuable role in investigating the aetiology of pain syndromes. The aim of this review was to synthesise and appraise the current literature on neuroimaging studies of pain syndromes in MS.

Methods

We systematically searched PubMed and Scopus from their inception dates to the 2nd of April 2013. Studies were selected by predefined inclusion and exclusion criteria. Methodological quality was appraised. Descriptive statistical analysis was conducted.

Results

We identified 38 studies of variable methodology and quality. All studies but one used conventional structural magnetic resonance imaging, and the majority reported a positive association between location of demyelinating lesions and specific neuropathic pain syndromes. Most investigated headache and facial pain, with more common pain syndromes such as limb pain being relatively understudied. We identified a number of methodological concerns, which along with variable study design and reporting limit our ability to synthesise data. Higher quality studies were however less likely to report positive associations of lesion distribution to pain syndromes.

Conclusions

Further high quality hypothesis-driven neuroimaging studies of pain syndromes in MS are required to clarify pain mechanisms, particularly for the commonest pain syndromes.

•

We reviewed neuroimaging studies of pain syndromes in multiple sclerosis (MS).

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All studies investigated neuropathic pain or headache, mainly using structural MRI.

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Most reported associations between location of demyelinating lesions and pain.

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Culprit lesions were most commonly reported in the brainstem.

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High quality hypothesis-driven neuroimaging studies of pain in MS are still needed.

Combined anti CXC receptors 1 and 2 therapy is a promising anti-inflammatory treatment for respiratory diseases by reducing neutrophil migration and activation

Neutrophil infiltration and activation in the lung are important pathophysiological features in COPD, severe asthma and bronchiectasis mostly mediated by CXCL8 and CXCL1 via CXCR1 and CXCR2. No thorough study to date has been performed to compare the anti-inflammatory effect profile of dual CXCR1/2 vs. selective CXCR2 antagonists in relevant human neutrophil assays and pulmonary inflammation models. Dual CXCR1/2 (SCH527123, diaminocyclobutandione-1) and selective CXCR2 (SB265610, thiopyrimidine-1) antagonist activity and receptor residence time were determined by [(35)S]GTPγS binding in human (h)- and guinea pig (gp)-CXCR1 and CXCR2 overexpressing membranes. h-neutrophil chemotaxis, degranulation and ROS production were established using CXCL8 or CXCL1 to evaluate dual CXCR1/2- or selective CXCR2-dependent activities. LPS-induced lung inflammation in gp was selected to assess in vivo potency. Dual CXCR1/2 antagonists blocked both CXCL8 and CXCL1-induced h-neutrophil functions and [(35)S]GTPγS binding. In contrary, selective CXCR2 antagonists displayed significantly reduced potency in CXCL8 -mediated h-neutrophil responses despite being active in CXCR2 assays. Upon LPS challenge in gp, administration of SCH527123 inhibited the increase of neutrophils in BALF, modestly reduced blood neutrophils and induced minor neutrophil accumulation in bone marrow. Differentiation of CXCR1/2 vs. CXCR2 antagonists could not be extended to in vivo due to differences in CXCR1 receptor homology between h and gp. Dual CXCR1/2 therapy may represent a promising anti-inflammatory treatment for respiratory diseases reducing more effectively neutrophil migration and activation in the lung than a CXCR2 selective treatment. However, the in vivo confirmation of this claim is still missing due to species differences in CXCR1.

Comparison between the GHQ-28 and SF-36 (MH 1-5) for the assessment of the mental health in patients with ischaemic heart disease

OBJECTIVE

To assess the mental health of patients admitted to hospital with suspected ischaemic heart disease, by means of two instruments, the General Health Questionnaire (GHQ-28) and the MH (1-5) dimension of the SF-36 Health Survey Questionnaire, and to compare the psychometric properties of both questionnaires in this population.

METHODS

A study was conducted of 185 patients consecutively admitted to hospital with suspected ischaemic heart disease, classified into four groups: Acute Myocardial Infarctus (AMI), unstable angina, non-ischaemic cardiologies, and non-cardiological conditions. Their mental health was assessed by means of the GHQ-28 and the MH 1-5 sub-scales of the SF-36; the validity of the results were analysed by the association of each instrument with socio-demographic (age, sex, social class, and educational level) and clinical (co-morbidity, risk factors, diagnostic groups and background to the illness) variables. The correlation of each instrument with other sub-scales of the SF-36 was studied. The internal consistency was measured by Cronbach's alpha, together with the item-internal consistency and item-discriminant validity.

RESULTS

Of the population studied, 71.9% were males and the mean age was 60.2 years (SD: 10.4). The diagnosis for 33.5% was AMI and for 37.8% unstable angina. For all the variables studied, the scores in the two instruments were ordered in the same way, and were significantly worse for females and for the most disadvantaged social class. None of the scales discriminated in respect of the diagnostic group or the presence of comorbidity. However, a linear relationship was observed with risk factors. Cronbach's alpha was 0.95 for the GHQ-28 and 0.80 for the MH 1-5. Correlations with the other dimensions showed ranges of -0.35 to -0.61 for the GHQ-28 and of 0.26 to 0.61 for the MH 1-5. These were highest for the Vitality and Social Functioning sub-scales in both instruments.

CONCLUSIONS

The subjective perception of mental health is measured in a similar way by both the MH 1-5 scale of the SF-36 and the GHQ-28. However, since the MH 1-5 questionnaire is shorter, it should be administratively easier to introduce into routine cardiological practice.

Acidocalcisomes as calcium- and polyphosphate-storage compartments during embryogenesis of the insect Rhodnius prolixus Stahl

BACKGROUND

The yolk of insect eggs is a cellular domain specialized in the storage of reserve components for embryo development. The reserve macromolecules are stored in different organelles and their interactions with the embryo cells are mostly unknown. Acidocalcisomes are lysosome-related organelles characterized by their acidic nature, high electron density and large content of polyphosphate bound to several cations. In this work, we report the presence of acidocalcisome-like organelles in eggs of the insect vector Rhodnius prolixus.

METHODOLOGY/PRINCIPAL FINDINGS

Characterization of the elemental composition of electron-dense vesicles by electron probe X-ray microanalysis revealed a composition similar to that previously described for acidocalcisomes. Following subcellular fractionation experiments, fractions enriched in acidocalcisomes were obtained and characterized. Immunofluorescence showed that polyphosphate polymers and the vacuolar proton translocating pyrophosphatase (V-H(+)-PPase, considered as a marker for acidocalcisomes) are found in the same vesicles and that these organelles are mainly localized in the egg cortex. Polyphosphate quantification showed that acidocalcisomes contain a significant amount of polyphosphate detected at day-0 eggs. Elemental analyses of the egg fractions showed that 24.5±0.65% of the egg calcium are also stored in such organelles. During embryogenesis, incubation of acidocalcisomes with acridine orange showed that these organelles are acidified at day-3 (coinciding with the period of yolk mobilization) and polyphosphate quantification showed that the levels of polyphosphate tend to decrease during early embryogenesis, being approximately 30% lower at day-3 compared to day-0 eggs.

CONCLUSIONS

We found that acidocalcisomes are present in the eggs and are the main storage compartments of polyphosphate and calcium in the egg yolk. As such components have been shown to be involved in a series of dynamic events that may control embryo growth, results reveal the potential involvement of a novel organelle in the storage and mobilization of inorganic elements to the embryo cells.

The biology of the germ line in echinoderms

The formation of the germ line in an embryo marks a fresh round of reproductive potential. The developmental stage and location within the embryo where the primordial germ cells (PGCs) form, however, differs markedly among species. In many animals, the germ line is formed by an inherited mechanism, in which molecules made and selectively partitioned within the oocyte drive the early development of cells that acquire this material to a germ-line fate. In contrast, the germ line of other animals is fated by an inductive mechanism that involves signaling between cells that directs this specialized fate. In this review, we explore the mechanisms of germ-line determination in echinoderms, an early-branching sister group to the chordates. One member of the phylum, sea urchins, appears to use an inherited mechanism of germ-line formation, whereas their relatives, the sea stars, appear to use an inductive mechanism. We first integrate the experimental results currently available for germ-line determination in the sea urchin, for which considerable new information is available, and then broaden the investigation to the lesser-known mechanisms in sea stars and other echinoderms. Even with this limited insight, it appears that sea stars, and perhaps the majority of the echinoderm taxon, rely on inductive mechanisms for germ-line fate determination. This enables a strongly contrasted picture for germ-line determination in this phylum, but one for which transitions between different modes of germ-line determination might now be experimentally addressed.

Morphine determination by gas chromatography/mass spectroscopy in human vitreous humor and comparison with radioimmunoassay

A gas chromatographic-mass spectroscopic method (GC/MS) for morphine determination in human vitreous humor was developed. Reversed-phase solid-liquid extraction gave better sample purification compared with liquid-liquid or normal-phase solid-liquid extractions. In 10 real cases of death by heroin overdose, the correlation between the results obtained by GC/MS and by radioimmunoassay (RIA) was studied.

Does umbilical vein catheterization to exchange transfusion lead to portal vein thrombosis?

The aetiopathology of extrahepatic portal vein obstruction is unknown. In retrospective studies, umbilical vein cannulation and sepsis have been alleged to cause portal thrombosis. This prospective study was undertaken to detect whether thrombosis and consequent obstruction of the splenoportal venous system develops after umbilical vein catheterization for exchange transfusion in newborns using Doppler ultrasound. Forty children (M = 24; F = 16) who had undergone exchange transfusion for hyperbilirubinaemia were studied at school age. Maximal duration of the venous umbilical cannulation was 120 min and sepsis did not occur. Clinical, biological and sonographic examinations were normal, except in 3 children. In 2 the left branch of portal vein could not be identified (normal variant).

CONCLUSION

Our results show that, in these children, umbilical vein catheterization did not lead to development of portal vein thrombosis. However, when other risk factors such as umbilical infection, traumatic catheterization are associated, children should be screened for obstruction of the portal vein.

Calcium pathway machinery at fertilization in echinoderms

Calcium signaling in cells directs diverse physiological processes. The calcium waves triggered by fertilization is a highly conserved calcium signaling event essential for egg activation, and has been documented in every egg tested. This activity is one of the few highly conserved events of egg activation through the course of evolution. Echinoderm eggs, as well as many other cell types, have three main intracellular Ca(2+) mobilizing messengers - IP3, cADPR and NAADP. Both cADPR and NAADP were identified as Ca(2+) mobilizing messengers using the sea urchin egg homogenate, and this experimental system, along with the intact urchin and starfish oocyte/egg, continues to be a vital tool for investigating the mechanism of action of calcium signals. While many of the major regulatory steps of the IP3 pathway are well resolved, both cADPR and NAADP remain understudied in terms of our understanding of the fundamental process of egg activation at fertilization. Recently, NAADP has been shown to trigger Ca(2+) release from acidic vesicles, separately from the ER, and a new class of calcium channels, the two-pore channels (TPCs), was identified as the likely targets for this messenger. Moreover, it was found that both cADPR and NAADP can be synthesized by the same family of enzymes, the ADP-rybosyl cyclases (ARCs). In this context of increasing amount of information, the potential coupling and functional roles of different messengers, intracellular stores and channels in the formation of the fertilization calcium wave in echinoderms will be critically evaluated.

Inhibition of rat liver microsomal lipid peroxidation elicited by 2,2-dimethylchromenes and chromans containing fluorinated moieties resistant to cytochrome P-450 metabolism

2,2-Dimethylchromenes and chromans containing cytochrome P-450 resistant 2,2,2-trifluoroethoxy aryl substituents were synthesized and their activity as lipid peroxidation inhibitors evaluated and compared with that exhibited by the corresponding non-fluorinated derivatives. Lipid peroxidation was stimulated in rat liver microsomes by addition of Fe-ascorbate or NADPH, and determined with the TBARS (thiobarbituric acid reactive substances) test. In assays using Fe-ascorbate stimulation, only those derivatives with a OH group at C6 (i.e. 6 and 12) elicited good inhibitory activities (IC50 = 6.0 and 5.3 microM, respectively). In respect to the NADPH dependent incubations, inhibitory activity of compound 11 (IC50 = 6.0 microM) was the highest found within the 6,7-dialkoxy derivatives tested. Results on metabolism assays with this compound showed the generation of phenol 12 (i.e. the putative active antioxidant species); on the other hand, no metabolite resulting from dealkylation at C7 was detected, thus confirming the resistance conferred by the CF3CH2O group to the cytochrome P-450 promoted cleavage. Finally, in assays where incubations in the presence of NADPH were prolonged up to three hours, inhibitory activity of the non-fluorinated 6,7-dialkoxychroman 8 remained constant, thus suggesting that a continued release of the species responsible for the inhibitory activity was produced. However, inhibition elicited by the fluorinated analog 11 showed a small decrease during the third hour of incubation. This decrease could be attributed to the slight inhibition of the cytochrome P-450 metabolism exerted by substrates bearing the CF3CH2O substituent, which would decelerate the generation of the active phenol species.(ABSTRACT TRUNCATED AT 250 WORDS)

Morbidity and mortality outcomes after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in patients aged 75 years and over: Spanish group of peritoneal cancer surgery (GECOP) multicenter study

BACKGROUND

The aim of this study is to report the perioperative outcomes of cytoreductive surgery and hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC) in patients ≥75 years from a Spanish multi-institutional experience.

METHODS

This multi-institutional retrospectively analyzed a prospectively collected clinical data from 10 Spanish hospitals that are part of the Spanish Group Peritoneal Cancer Surgery (GECOP). We assessed postoperative morbidity rates and performed univariate and multivariate analyses of factors associated with overall (grade I-IV) and major (grade III-IV) postoperative morbidity.

RESULTS

A total of 85 patients aged ≥75 years were included. Forty six postoperative adverse events were detected in 37 patients (43.5%). Twenty five complications in 20 patients (23.5%) were mild (grade I-II) and 16 complications in 12 patients (14.1%) were moderate-severe (grade III-IV). Five patients died in the first 90 days after the procedure (5.9%). After multivariate analysis, independent factors associated with postoperative complications were: PCI> 12 (OR: 4.14, 95% CI 1.22-14.12, p = 0.043) and the need for perioperative blood transfusion (OR: 14.91, 95% CI 3.87-57.46, p < 0.001). Regarding grade III-IV complications, after multivariate analysis, the presence of preoperative albumin levels <3.5 mgr/dl (OR: 9.15, 95% CI 1.38-60.57, p = 0.017), need for diaphragmatic peritonectomy procedures (OR: 11.32, 95% CI 1.40-91.32, p = 0.023) and perioperative blood transfusion (OR: 8.58, 95% CI 1.44-51.16, p = 0.018) were independent factors.

CONCLUSIONS

Cytoreductive surgery and performing HIPEC by experienced groups in selected patients aged ≥75 years can be performed with morbidity and mortality similar to that described in the literature.

Anthranilate synthase can generate sufficient phosphoribosyl amine for thiamine synthesis in Salmonella enterica

In bacteria, the biosynthetic pathway for the hydroxymethyl pyrimidine moiety of thiamine shares metabolic intermediates with purine biosynthesis. The two pathways branch after the compound aminoimidazole ribotide. Past work has shown that the first common metabolite, phosphoribosyl amine (PRA), can be generated in the absence of the first enzyme in purine biosynthesis, PurF. PurF-independent PRA synthesis is dependent on both strain background and growth conditions. Standard genetic approaches have not identified a gene product singly responsible for PurF-independent PRA formation. This result has led to the hypothesis that multiple enzymes contribute to PRA synthesis, possibly as the result of side products from their dedicated reaction. A mutation that was able to restore PRA synthesis in a purF gnd mutant strain was identified and found to map in the gene coding for the TrpD subunit of the anthranilate synthase (AS)-phosphoribosyl transferase (PRT) complex. Genetic analyses indicated that wild-type AS-PRT was able to generate PRA in vivo and that the P362L mutant of TrpD facilitated this synthesis. In vitro activity assays showed that the mutant AS was able to generate PRA from ammonia and phosphoribosyl pyrophosphate. This work identifies a new reaction catalyzed by AS-PRT and considers it in the context of cellular thiamine synthesis and metabolic flexibility.

Silencing of ATG6 and ATG8 promotes increased levels of triacylglycerol (TAG) in the fat body during prolonged starvation periods in the Chagas disease vector Rhodnius prolixus

Rhodnius prolixus is an obligatorily hematophagous insect known as an important vector of Chagas disease. Autophagy is a conserved cellular mechanism that acts in response to nutrient starvation, where components of the cytoplasm are sequestered by a double membrane organelle, named autophagosome, which is targeted to fuse with the lysosome for degradation. Lipophagy is the process of lipid degradation by selective autophagy, where autophagosomes sequester lipid droplets and degrade triacylglycerol (TAG) generating free fatty acids for β-oxidation. Here, two essential genes of the autophagic pathway, Atg6/Beclin1 (RpAtg6) and Atg8/LC3 (RpAtg8), were silenced and the storage of lipids during starvation in Rhodnius prolixus was monitored. We found that RNAi knockdown of both RpAtg6 and RpAtg8 resulted in higher levels of TAG in the fat body and the flight muscle, 24 days after the blood meal, as well as a larger average diameter of the lipid droplets in the fat body, as seen by Nile Red staining under the confocal fluorescence microscope. Silenced starved insects had lower survival rates when compared to control insects. Accordingly, when examined during the starvation period for monitored activity, silenced insects had lower spontaneous locomotor activity and lower forced flight rates. Furthermore, we found that some genes involved in lipid metabolism had their expression levels altered in silenced insects, such as the Brummer lipase (down regulated) and the adipokinetic hormone receptor (up regulated), suggesting that, as previously observed in mammalian models, the autophagy and neutral lipolysis machineries are interconnected at the transcriptional level. Altogether, our data indicate that autophagy in the fat body is important to allow insects to mobilize energy from lipid stores.

Diffusion-weighted imaging: determination of the best pair of b-values to discriminate breast lesions

OBJECTIVE

In breast diffusion-weighted imaging (DWI), the apparent diffusion coefficient (ADC) is used to discriminate between malignant and benign lesions. As ADC estimates can be affected by the weighting factors, our goal was to determine the optimal pair of b-values for discriminating breast lesions at 3.0 T.

METHODS

152 females with 157 lesions (89 malignant and 68 benign) underwent breast MRI, including a DWI sequence sampling six b-values 50, 200, 400, 600, 800 and 1000 s mm(-2). ADC values were computed from different pairs of b-values and compared with ADC obtained by fitting the six b-values using a mono-exponential diffusion model (ADCall). Cut-off ADC values were determined and diagnostic performance evaluated by receiver operating characteristic analysis using Youden statistics. Mean ADCs were determined for normal tissue and lesions. Differences were evaluated by lesion and histological types.

RESULTS

Considering the cut-off values 1.46 and 1.49 × 10(3)mm(2) s(-1), the pairs 50, 1000 and 200, 800 s mm(-2) showed the highest accuracy, 77.5% and 75.4% with areas under the curve 84.4% and 84.2%, respectively. The best pair for ADC quantification was 50, 1000 s mm(-2) with 38/49 true-negative and 69/89 true-positive cases respectively; mean ADCs were 1.86 ± 0.46, 1.77 ± 0.37 and 1.15 ± 0.46 × 10(-3) mm(2) s(-1) for normal, benign and malignant lesions. There were no significant differences in these ADC values when compared with ADCall (ADC calculated from the full set of b - values) [difference = 0.0075 × 10(-3) mm(2) s(-1); confidence interval 95%: (-0.0036; 0.0186); p = 0.18].

CONCLUSION

The diagnostic performance in differentiating malignant and benign lesions was most accurate for the b-value pair 50, 1000 s mm(-2).

ADVANCES IN KNOWLEDGE

The best b-value pair for lesion discrimination and characterization through ADC quantification was 50, 1000 s mm(-2).

Lack of activity of 15-epi-lipoxin A₄ on FPR2/ALX and CysLT1 receptors in interleukin-8-driven human neutrophil function

Neutrophil recruitment and survival are important control points in the development and resolution of inflammatory processes. 15-epi-lipoxin (LX)A interaction with formyl peptide receptor 2 (FPR2)/ALX receptor is suggested to enhance anti-inflammatory neutrophil functions and mediate resolution of airway inflammation. However, it has been reported that 15-epi-LXA₄ analogues can also bind to cysteinyl leukotriene receptor 1 (CysLT1) and that the CysLT1 antagonist MK-571 binds to FPR2/ALX, so cross-reactivity between FPR2/ALX and CysLT1 ligands cannot be discarded. It is not well established whether the resolution properties reported for 15-epi-LXA4 are mediated through FPR2/ALX, or if other receptors such as CysLT1 may also be involved. Evaluation of specific FPR2/ALX ligands and CysLT1 antagonists in functional biochemical and cellular assays were performed to establish a role for both receptors in 15-epi-LXA₄-mediated signalling and function. In our study, a FPR2/ALX synthetic peptide (WKYMVm) and a small molecule FPR2/ALX agonist (compound 43) induced FPR2/ALX-mediated signalling, enhancing guanosine triphosphate-gamma (GTPγ) binding and decreasing cyclic adenosine monophosphate (cAMP) levels, whereas 15-epi-LXA₄ was inactive. Furthermore, 15-epi-LXA4 showed neither binding affinity nor signalling towards CysLT1. In neutrophils, 15-epi-LXA₄ showed a moderate reduction of interleukin (IL)-8-mediated neutrophil chemotaxis but no effect on neutrophil survival was observed. In addition, CysLT1 antagonists were inactive in FPR2/ALX signalling or neutrophil assays. In conclusion, 15-epi-LXA₄ is not a functional agonist or an antagonist of FPR2/ALX or CysLT1, shows no effect on IL-8-induced neutrophil survival and produces only moderate inhibition in IL-8-mediated neutrophil migration. Our data do not support an anti-inflammatory role of 15-epi-LXA₄- FPR2/ALX interaction in IL-8-induced neutrophil inflammation.

Silencing of RpATG6 impaired the yolk accumulation and the biogenesis of the yolk organelles in the insect vector R. prolixus

In oviparous animals, the egg yolk is synthesized by the mother in a major metabolic challenge, where the different yolk components are secreted to the hemolymph and delivered to the oocytes mostly by endocytosis. The yolk macromolecules are then stored in a wide range of endocytic-originated vesicles which are collectively referred to as yolk organelles and occupy most of the mature oocytes cytoplasm. After fertilization, the contents of these organelles are degraded in a regulated manner to supply the embryo cells with fundamental molecules for de novo synthesis. Yolk accumulation and its regulated degradation are therefore crucial for successful development, however, most of the molecular mechanisms involved in the biogenesis, sorting and degradation of targeted yolk organelles are still poorly understood. ATG6 is part of two PI3P-kinase complexes that can regulate the recruitment of the endocytic or the autophagy machineries. Here, we investigate the role of RpATG6 in the endocytosis of the yolk macromolecules and in the biogenesis of the yolk organelles in the insect vector Rhodnius prolixus. We found that vitellogenic females express high levels of RpATG6 in the ovaries, when compared to the levels detected in the midgut and fat body. RNAi silencing of RpATG6 resulted in yolk proteins accumulated in the vitellogenic hemolymph, as a consequence of poor uptake by the oocytes. Accordingly, the silenced oocytes are unviable, white (contrasting to the control pink oocytes), smaller (62% of the control oocyte volume) and accumulate only 40% of the yolk proteins, 80% of the TAG and 50% of the polymer polyphosphate quantified in control oocytes. The cortex of silenced oocytes present atypical smaller vesicles indicating that the yolk organelles were not properly formed and/or sorted, which was supported by the lack of endocytic vesicles near the plasma membrane of silenced oocytes as seen by TEM. Altogether, we found that RpATG6 is central for the mechanisms of yolk accumulation, emerging as an important target for further investigations on oogenesis and, therefore, reproduction of this vector.