Pangenomic Analysis of Nucleo-Cytoplasmic Large DNA Viruses. I: The Phylogenetic Distribution of Conserved Oxygen-Dependent Enzymes Reveals a Capture-Gene Process

The Nucleo-Cytoplasmic Large DNA Viruses (NCLDVs) infect a wide range of eukaryotic species, including amoeba, algae, fish, amphibia, arthropods, birds, and mammals. This group of viruses has linear or circular double-stranded DNA genomes whose size spans approximately one order of magnitude, from 100 to 2500 kbp. The ultimate origin of this peculiar group of viruses remains an open issue. Some have argued that NCLDVs' origin may lie in a bacteriophage ancestor that increased its genome size by subsequent recruitment of eukaryotic and bacterial genes. Others have suggested that NCLDVs families originated from cells that underwent an irreversible process of genome reduction. However, the hypothesis that a number of NCLDVs sequences have been recruited from the host genomes has been largely ignored. In the present work, we have performed pangenomic analyses of each of the seven known NCLDVs families. We show that these families' core- and shell genes have cellular homologs, supporting possible escaping-gene events as part of its evolution. Furthermore, the detection of sequences that belong to two protein families (small chain ribonucleotide reductase and Erv1/Air) and to one superfamily [2OG-Fe(II) oxygenases] that are for distribution in all NCLDVs core and shell clusters encoding for oxygen-dependent enzymes suggests that the highly conserved core these viruses originated after the Proterozoic Great Oxidation Event that transformed the terrestrial atmosphere 2.4-2.3 Ga ago.

Maternal health among Venezuelan women migrants at the border of Brazil

BACKGROUND

Guaranteeing the sexual and reproductive health and rights (SRHR) of populations living in fragile and humanitarian settings is essential and constitutes a basic human right. Compounded by the inherent vulnerabilities of women in crises, substantial complications are directly associated with increased risks of poor SRHR outcomes for displaced populations. The migration of Venezuelans, displaced due to current economic circumstances, is one of the largest in Latin America's history. This study aims to provide an overview of the sexual and reproductive health (SRH) issues affecting migrant Venezuelan women in the state of Roraima, Brazil.

METHODS

Face-to-face interviews were conducted from 24 to 30 November 2019. Data collection covered various issues involving access to and use of SRH services by 405 migrant Venezuelan women aged 18-49 years. The Minimum Initial Service Package readiness assessment tools, available from the Inter-Agency Working Group on Reproductive Health in Crises, were used in the data collection.

RESULTS

Most commonly, the women reported unmet family planning needs. Of these, a significant proportion reported being unable to obtain contraceptive methods, particularly long-acting reversible contraceptives, either due to the woman's inability to access them or their unavailability at healthcare centres. Although a significant proportion of women were largely satisfied with the attention received at the maternity hospital, both before and during childbirth, 24.0% of pregnant or postpartum women failed to receive any prenatal or postnatal care.

CONCLUSION

Meeting the essential SRHR needs of migrant Venezuelan women in Roraima, Brazil is a challenge that has yet to be fully addressed. Given the size of this migrant population, the Brazilian healthcare system has failed to adapt sufficiently to meet their needs; however, problems with healthcare provision are similar for migrants and Brazilian citizens. Efforts need to be encouraged not only in governmental health sectors, but also with academic, non-governmental and international organisations, including a coordinated approach to ensure a comprehensive SRHR response. Given the current high risks associated with the SARS-CoV-2 pandemic, meeting the SRHR needs of migrant populations has become more critical than ever.

Critical contribution of Na+-Ca2+ exchanger to the Ca2+-mediated vasodilation activated in endothelial cells of resistance arteries

Na⁺-Ca²⁺ exchanger (NCX) contributes to control the intracellular free Ca²⁺ concentration ([Ca²⁺]_i), but the functional activation of NCX reverse mode (NCXrm) in endothelial cells is controversial. We evaluated the participation of NCXrm-mediated Ca²⁺ uptake in the endothelium-dependent vasodilation of rat isolated mesenteric arterial beds. In phenylephrine-contracted mesenteries, the acetylcholine (ACh)-induced vasodilation was abolished by treatment with the NCXrm blockers SEA0400, KB-R7943, or SN-6. Consistent with that, the ACh-induced hyperpolarization observed in primary cultures of mesenteric endothelial cells and in smooth muscle of isolated mesenteric resistance arteries was attenuated by KB-R7943 and SEA0400, respectively. In addition, both blockers abolished the NO production activated by ACh in intact mesenteric arteries. In contrast, the inhibition of NCXrm did not affect the vasodilator responses induced by the Ca²⁺ ionophore, ionomycin, and the NO donor, S-nitroso- N-acetylpenicillamine. Furthermore, SEA0400, KB-R7943, and a small interference RNA directed against NCX1 blunted the increase in [Ca²⁺]_i induced by ACh or ATP in cultured endothelial cells. The analysis by proximity ligation assay showed that the NO-synthesizing enzyme, eNOS, and NCX1 were associated in endothelial cell caveolae of intact mesenteric resistance arteries. These results indicate that the activation of NCXrm has a central role in Ca²⁺-mediated vasodilation initiated by ACh in endothelial cells of resistance arteries.-Lillo, M. A., Gaete, P. S., Puebla, M., Ardiles, N. M., Poblete, I., Becerra, A., Simon, F., Figueroa, X. F. Critical contribution of Na⁺-Ca²⁺ exchanger to the Ca²⁺-mediated vasodilation activated in endothelial cells of resistance arteries.

Complications Associated With Liver Transplantation in Recipients With Body Mass Index >35 kg/m(2): Would It Be a Poor Prognosis Predictive Factor?

BACKGROUND

Obesity is a global epidemic that continues to increase in a great number of countries, and it has become a major public health problem in Spain. Unfortunately, the impact of obesity on survival in liver transplantation (LT) recipients is underestimated and controversial. The aim of this study was to determine if obesity is a risk factor for morbidity and mortality after LT.

METHODS

In a retrospective cohort study of the records of 180 consecutive patients who had undergone to LT from 2007 to 2013, 11 obese patients with body mass index (BMI) >35 kg/m(2) were identified. Their data have been compared with recipients with BMI 20-25 kg/m(2).

RESULTS

There were no differences in demographic data, Child-Pugh score, Model for End-Stage Liver Disease score, or cause of liver failure. BMI >35 kg/m(2) recipients had a significantly higher rate of portal vein thrombosis before LT, compared with the BMI 20-25 kg/m(2) group (36.5% vs 13.9%; P = .041). There were also no differences in development of post-reperfusion syndrome. The groups were also comparable concerning morbidity rate after LT, stay in the intensive care unit, and global hospital stay. However, the mortality rate was significantly higher in the obese group compared with the nonobese group (72.7% vs 38.9%; P = .032).

CONCLUSIONS

The results of the study clearly demonstrate higher mortality rates in obese patients undergoing LT; thus, it is fair to consider obesity as a poor prognosis predictive factor concerning mortality rate.

Influence of Waiting List in Recurrence Disease of Hepatocellular Carcinoma

BACKGROUND

We describe the results of our liver transplantation (LT) patients for hepatocellular carcinoma (HCC) in 2004 to 2012 to determine the differences on the basis of time on the waiting list to establish the risk of recurrence of liver disease.

METHODS

Clinical variables were recorded for both donors and recipients as well as variables of diagnosis, the use of transarterial chemoembolization during the waiting list time (WLT), complications, re-transplantation, and exitus. Fifty-eight patients were analyzed. Mean age was 57 ± 8 years (men, 83%; 48 patients). Viral etiology of HCC was 50% (n = 29); alcoholic, 26% (n = 15); and others, 24% (n = 14).

RESULTS

Exitus was established in 24 patients (41%); only 5 patients (7%) were attributable to HCC. In the cohort of patients with less than 6 months of WLT, we registered both higher rates of downstaging protocols (10.7% vs 7.5%) and tumor size (3 cm vs 2 cm) compared with the other group. Bivariate studies were conducted according to the WLT (WLT <6 months, WLT ≥6 months), finding differences in recurrence of liver disease (P < .05). This fact was confirmed after a binary logistic regression.

CONCLUSIONS

Our results in a subgroup of less than 6 months of WLT included patients with increased tumor size or presentation of multiple nodes, with a worse prognosis and therefore to be prioritized in the treatment of LT. Therefore, in our population there is a significant risk of tumor recurrence in patients with less WLT for LT, but it cannot be overestimated to all type of patients with HCC.

Excess iodide induces an acute inhibition of the sodium/iodide symporter in thyroid male rat cells by increasing reactive oxygen species

Na+/I- symporter (NIS) mediates iodide (I-) uptake in the thyroid gland, the first and rate-limiting step in the biosynthesis of the thyroid hormones. The expression and function of NIS in thyroid cells is mainly regulated by TSH and by the intracellular concentration of I-. High doses of I- for 1 or 2 days inhibit the synthesis of thyroid hormones, a process known as the Wolff-Chaikoff effect. The cellular mechanisms responsible for this physiological response are mediated in part by the inhibition of I- uptake through a reduction of NIS expression. Here we show that inhibition of I- uptake occurs as early as 2 hours or 5 hours after exposure to excess I- in FRTL-5 cells and the rat thyroid gland, respectively. Inhibition of I- uptake was not due to reduced NIS expression or altered localization in thyroid cells. We observed that incubation of FRTL-5 cells with excess I- for 2 hours increased H2O2 generation. Furthermore, the inhibitory effect of excess I- on NIS-mediated I- transport could be recapitulated by H2O2 and reverted by reactive derived oxygen species scavengers. The data shown here support the notion that excess I- inhibits NIS at the cell surface at early times by means of a posttranslational mechanism that involves reactive derived oxygen species.

Increases in reactive oxygen species enhance vascular endothelial cell migration through a mechanism dependent on the transient receptor potential melastatin 4 ion channel

A hallmark of severe inflammation is reactive oxygen species (ROS) overproduction induced by increased inflammatory mediators secretion. During systemic inflammation, inflammation mediators circulating in the bloodstream interact with endothelial cells (ECs) raising intracellular oxidative stress at the endothelial monolayer. Oxidative stress mediates several pathological functions, including an exacerbated EC migration. Because cell migration critically depends on calcium channel-mediated Ca(2+) influx, the molecular identification of the calcium channel involved in oxidative stress-modulated EC migration has been the subject of intense investigation. The transient receptor potential melastatin 4 (TRPM4) protein is a ROS-modulated non-selective cationic channel that performs several cell functions, including regulating intracellular Ca(2+) overload and Ca(2+) oscillation. This channel is expressed in multiple tissues, including ECs, and contributes to the migration of certain immune cells. However, whether the TRPM4 ion channel participates in oxidative stress-mediated EC migration is not known. Herein, we investigate whether oxidative stress initiates or enhances EC migration and study the role played by the ROS-modulated TRPM4 ion channel in oxidative stress-mediated EC migration. We demonstrate that oxidative stress enhances, but does not initiate, EC migration in a dose-dependent manner. Notably, we demonstrate that the TRPM4 ion channel is critical in promoting H2O2-enhanced EC migration. These results show that TRPM4 is a novel pharmacological target for the possible treatment of severe inflammation and other oxidative stress-mediated inflammatory diseases.

Experience of the transplant unit from Virgen de las Nieves Hospital in using liver grafts from asystolic donors

Given the shortage of donors, it has become increasingly necessary to use alternative sources to meet the growing demand for organs, and evolution in the use of asystolic donors is proving to be an important resource in helping to meet those needs. The goal of this study is to describe the initial results of our experience with Type II asystolic donation. An observational retrospective study was conducted to analyze the variables of four cases in this type of donation. After the analysis we conclude that, despite the limited number of cases in our series, the results are compatible with larger series and permit us to continue to value this method as a resource for broadening the donor pool.

Liver transplantation using low-weight recipients from a graft split program

We present our experience with a split liver (SL) program shared with the children's liver transplantation (LT) program from 2 different hospitals in the use of partial grafts from cadaver donors in brain death. We describe an observational, retrospective study, which included patients who underwent a SL transplantation in our center between January 2006 and December 2012. Clinical variables were recorded of both donors and recipients and their data were analyzed using SPSS 19.0 software. Of a total of 204 LT, 4 (2%) patients were treated with a SL. The causes of LT were alcoholic cirrhosis in 2 cases, cryptogenic cirrhosis, and primary biliary cirrhosis (PBC). In all cases there was a temporary portocaval shunt. The confluence of the hepatic veins of the recipient was anastomosed to the donor vena cava and arterial anastomosis was performed. The reconstruction was hepato-choledochal in all cases. There were no cases of postreperfusion syndrome or vascular thrombosis and no retransplantation was necessary. Currently, 3 of the 4 cases are still alive. Death in the other patient was due to mesenteric ischemia. Our center has participated in the development of a protocol that considers the indication of this technique provided expert groups are involved in its development, regardless of hospital level. This will expand the pool of donors and partially solve the current problems with available grafting.

Ezh1 and Ezh2 differentially regulate PSD-95 gene transcription in developing hippocampal neurons

Polycomb Repressive Complex 2 (PRC2) mediates transcriptional silencing by catalyzing histone H3 lysine 27 trimethylation (H3K27me3), but its role in the maturation of postmitotic mammalian neurons remains largely unknown. We report that the PRC2 paralogs Ezh1 and Ezh2 are differentially expressed during hippocampal development. We show that depletion of Ezh2 leads to increased expression of PSD-95, a critical plasticity gene, and that reduced PSD-95 gene transcription is correlated with enrichment of Ezh2 at the PSD-95 gene promoter; however, the H3K27me3 epigenetic mark is not present at the PSD-95 gene promoter, likely due to the antagonizing effects of the H3S28P and H3K27Ac marks and the activity of the H3K27 demethylases JMJD3 and UTX. In contrast, increased PSD-95 gene transcription is accompanied by the presence of Ezh1 and elongation-engaged RNA Polymerase II complexes at the PSD-95 gene promoter, while knock-down of Ezh1 reduces PSD-95 transcription. These results indicate that Ezh1 and Ezh2 have antagonistic roles in regulating PSD-95 transcription.

Lipopolysaccharide induces a fibrotic-like phenotype in endothelial cells

Endothelial dysfunction is crucial in endotoxaemia-derived sepsis syndrome pathogenesis. It is well accepted that lipopolysaccharide (LPS) induces endothelial dysfunction through immune system activation. However, LPS can also directly generate actions in endothelial cells (ECs) in the absence of participation by immune cells. Although interactions between LPS and ECs evoke endothelial death, a significant portion of ECs are resistant to LPS challenge. However, the mechanism that confers endothelial resistance to LPS is not known. LPS-resistant ECs exhibit a fibroblast-like morphology, suggesting that these ECs enter a fibrotic programme in response to LPS. Thus, our aim was to investigate whether LPS is able to induce endothelial fibrosis in the absence of immune cells and explore the underlying mechanism. Using primary cultures of ECs and culturing intact blood vessels, we demonstrated that LPS is a crucial factor to induce endothelial fibrosis. We demonstrated that LPS was able and sufficient to promote endothelial fibrosis, in the absence of immune cells through an activin receptor-like kinase 5 (ALK5) activity-dependent mechanism. LPS-challenged ECs showed an up-regulation of both fibroblast-specific protein expression and extracellular matrix proteins secretion, as well as a down-regulation of endothelial markers. These results demonstrate that LPS is a crucial factor in inducing endothelial fibrosis in the absence of immune cells through an ALK5-dependent mechanism. It is noteworthy that LPS-induced endothelial fibrosis perpetuates endothelial dysfunction as a maladaptive process rather than a survival mechanism for protection against LPS. These findings are useful in improving current treatment against endotoxaemia-derived sepsis syndrome and other inflammatory diseases.

Release of gliotransmitters through astroglial connexin 43 hemichannels is necessary for fear memory consolidation in the basolateral amygdala

Recent in vitro evidence indicates that astrocytes can modulate synaptic plasticity by releasing neuroactive substances (gliotransmitters). However, whether gliotransmitter release from astrocytes is necessary for higher brain function in vivo, particularly for memory, as well as the contribution of connexin (Cx) hemichannels to gliotransmitter release, remain elusive. Here, we microinfused into the rat basolateral amygdala (BLA) TAT-Cx43L2, a peptide that selectively inhibits Cx43-hemichannel opening while maintaining synaptic transmission or interastrocyte gap junctional communication. In vivo blockade of Cx43 hemichannels during memory consolidation induced amnesia for auditory fear conditioning, as assessed 24 h after training, without affecting short-term memory, locomotion, or shock reactivity. The amnesic effect was transitory, specific for memory consolidation, and was confirmed after microinfusion of Gap27, another Cx43-hemichannel blocker. Learning capacity was recovered after coinfusion of TAT-Cx43L2 and a mixture of putative gliotransmitters (glutamate, glutamine, lactate, d-serine, glycine, and ATP). We propose that gliotransmitter release from astrocytes through Cx43 hemichannels is necessary for fear memory consolidation at the BLA. Thus, the present study is the first to demonstrate a physiological role for astroglial Cx43 hemichannels in brain function, making these channels a novel pharmacological target for the treatment of psychiatric disorders, including post-traumatic stress disorder.

A phylogenetic analysis using full-length viral genomes of South American dengue serotype 3 in consecutive Venezuelan outbreaks reveals a novel NS5 mutation

Dengue virus currently causes 50-100 million infections annually. Comprehensive knowledge about the evolution of Dengue in response to selection pressure is currently unavailable, but would greatly enhance vaccine design efforts. In the current study, we sequenced 187 new dengue virus serotype 3 (DENV-3) genotype III whole genomes isolated from Asia and the Americas. We analyzed them together with previously-sequenced isolates to gain a more detailed understanding of the evolutionary adaptations existing in this prevalent American serotype. In order to analyze the phylogenetic dynamics of DENV-3 during outbreak periods; we incorporated datasets of 48 and 11 sequences spanning two major outbreaks in Venezuela during 2001 and 2007-2008, respectively. Our phylogenetic analysis of newly sequenced viruses shows that subsets of genomes cluster primarily by geographic location, and secondarily by time of virus isolation. DENV-3 genotype III sequences from Asia are significantly divergent from those from the Americas due to their geographical separation and subsequent speciation. We measured amino acid variation for the E protein by calculating the Shannon entropy at each position between Asian and American genomes. We found a cluster of seven amino acid substitutions having high variability within E protein domain III, which has previously been implicated in serotype-specific neutralization escape mutants. No novel mutations were found in the E protein of sequences isolated during either Venezuelan outbreak. Shannon entropy analysis of the NS5 polymerase mature protein revealed that a G374E mutation, in a region that contributes to interferon resistance in other flaviviruses by interfering with JAK-STAT signaling was present in both the Asian and American sequences from the 2007-2008 Venezuelan outbreak, but was absent in the sequences from the 2001 Venezuelan outbreak. In addition to E, several NS5 amino acid changes were unique to the 2007-2008 epidemic in Venezuela and may give additional insight into the adaptive response of DENV-3 at the population level.

Increased expression of the transient receptor potential melastatin 7 channel is critically involved in lipopolysaccharide-induced reactive oxygen species-mediated neuronal death

AIMS

To assess the mechanisms involved in lipopolysaccharide (LPS)-induced neuronal cell death, we examined the cellular consequences of LPS exposure in differentiated PC12 neurons and primary hippocampal neurons.

RESULTS

Our data show that LPS is able to induce PC12 neuronal cell death without the participation of glial cells. Neuronal cell death was mediated by an increase in cellular reactive oxygen species (ROS) levels. Considering the prevalent role of specific ion channels in mediating the deleterious effect of ROS, we assessed their contribution to this process. Neurons exposed to LPS showed a significant intracellular Ca(2+) overload, and nonselective cationic channel blockers inhibited LPS-induced neuronal death. In particular, we observed that both LPS and hydrogen peroxide exposure strongly increased the expression of the transient receptor protein melastatin 7 (TRPM7), which is an ion channel directly implicated in neuronal cell death. Further, both LPS-induced TRPM7 overexpression and LPS-induced neuronal cell death were decreased with dithiothreitol, dipheniliodonium, and apocynin. Finally, knockdown of TRPM7 expression using small interference RNA technology protected primary hippocampal neurons and differentiated PC12 neurons from the LPS challenge.

INNOVATION

This is the first report showing that TRPM7 is a key protein involved in neuronal death after LPS challenge.

CONCLUSION

We conclude that LPS promotes an abnormal ROS-dependent TRPM7 overexpression, which plays a crucial role in pathologic events, thus leading to neuronal dysfunction and death.

Preoperative natriuretic peptide-B values and ascites in male liver transplant recipients

Plasma preoperative values of natriuretic B peptide (pro-BNP) were correlated with ascites in men experiencing hepatic cirrhosis due to different etiologies on the active waiting list for liver transplantation. The study was performed in 54 male recipients of a liver transplant. Written informed consent was obtained from the patients or their relatives, and the study protocol was approved by our local Clinical Research (Ethics) Committee. Male patients were classified into two groups: group 1 included patients with alcoholic hepatic cirrhosis (n = 30) distributed as 19 men with no ascites, four with nonrefractory ascites, and seven with refractory ascites; group 2 included cases of viral hepatitis cirrhosis (n = 24) distributed as 13 men with no ascites, nine with non-refractory ascites, and two with refractory ascites. A group of six healthy male volunteers was used to establish normal (basal) values of pro-BNP and left auricular diameter (LAD). Pro-BNP values were determined in plasma samples by an electrochemiluminiscence immunoassay. Pro-BNP plasma levels in patients with alcoholic cirrhosis were threefold greater among patients with no ascites or no refractory ascites compared with healthy men, whereas pro-BNP values were fivefold enhanced among alcoholic patients with refractory ascites. The viral hepatitis cirrhosis group showed pro-BNP plasma values 1.5-fold enhanced in men with no ascites, whereas pro-BNP reached fivefold with either nonrefractory or refractory ascites. The enhanced pro-BNP plasma levels indicated advanced hepatic degradation, seemingly related to the presence of refractory ascites associated with cirrhosis.

Transient receptor potential melastatin 4 inhibition prevents lipopolysaccharide-induced endothelial cell death

AIMS

Endothelial dysfunction is decisive in the progression of cardiovascular diseases. Lipopolysaccharide (LPS)-induced reactive oxygen species (ROS)-mediated endothelial cell death is a main feature observed in inflammation secondary to endotoxaemia, emerging as a leading cause of death among critically ill patients in intensive care units. However, the molecular mechanism underlying LPS-induced endothelial cell death is not well understood. Transient receptor protein melastatin 4 (TRPM4) is an ion channel associated with cell death that is expressed in endothelium and modulated by ROS. Here, we investigate the role of TRPM4 in LPS-induced endothelial cell death, testing whether suppression of the expression of TRPM4 confers endothelial cell resistance to LPS challenge.

METHODS AND RESULTS

Using primary cultures of human umbilical vein endothelial cells (HUVEC), we demonstrate that TRPM4 is critically involved in LPS-induced endothelial cell death. HUVEC exposed to LPS results in Na(+)-dependent cell death. Pharmacological inhibition of TRPM4 with 9-phenanthrol or glibenclamide protects endothelium against LPS exposure for 48 h. Furthermore, TRPM4-like currents increase in cells pre-treated with LPS and inhibited with glibenclamide. Of note, suppression of TRPM4 expression by siRNA or suppression of its activity in a dominant negative mutant is effective in decreasing LPS-induced endothelial cell death when cells are exposed to LPS for 24-30 h.

CONCLUSION

TRPM4 is critically involved in LPS-induced endothelial cell death. These results demonstrate that either pharmacological inhibition of TRPM4, suppression of TRPM4 expression, or inhibition of TRPM4 activity are able to protect endothelium against LPS injury. These results are useful in sepsis drug design and development of new strategies for sepsis therapy.

Lipopolysaccharide signaling in the carotid chemoreceptor pathway of rats with sepsis syndrome

In addition to their role in cardiorespiratory regulation, carotid body (CB) chemoreceptors serve as sensors for inflammatory status and as a protective factor during sepsis. However, lipopolysaccharide-induced sepsis (LPS) reduces CB responsiveness to excitatory or depressant stimuli. We tested whether LPS exerts a direct effect on the carotid chemoreceptor pathway, the CB and its sensory ganglion. We determined that the rat CB and nodose-petrosal-jugular ganglion complex (NPJgc) express TLR4, TNF-α and its receptors (TNF-R1 and TNF-R2). LPS administration (15mg/kg intraperitoneally) evoked MyD88-mechanism pathway activation in CB and NPJgc, with NF-κB p65, p38 MAPK, and ERK activation. Consistently, LPS increased TNF-α and TNF-R2. Double-labeling studies showed that the aforementioned pathway occurs in TH-containing glomus cells and NPJgc neurons, components of the chemosensitive neural pathway. Thus, our results suggest that LPS acting directly through TLR4/MyD88-mechanism pathways increases TNF-α and TNF-R2 expression in the carotid chemoreceptor pathway. These results show a novel afferent pathway to the central nervous system during endotoxemia, and could be relevant in understanding sepsis pathophysiology and therapy.

[Clinical mycology and antifungals in the pediatric population]

Infections caused by Candida spp. and Aspergillus spp. account for 90% of all fungal infections and are the most significant causes of human morbidity and mortality. Candida albicans causes between 50 and 60% of all nosocomial fungal infections. The wet mount test and culture are the screening methods used in leading clinical laboratories for the detection of Candida spp. However, yeasts should be strictly classified mainly based on their physiological and biochemical characteristics, through a series of morphological and biochemical laboratory tests. As a result of the increase in systemic fungal infections and the spread of antifungal medications, it was necessary to establish standardized in vitro sensitivity tests as a guideline for the therapeutic decision-making process. Among antifungal agents available today we find antimycotics such as amphotericin B, 5-fluorocytosine (5-FC), fluconazole, voriconazole, posaconazole, and ravuconazole. Additionally, there is the recently developed group of echinocandines, which includes caspofungin, micafungin and anidulafungine.

A randomized cross-over study comparing cabergoline and quinagolide in the treatment of hyperprolactinemic patients

Quinagolide (QUI) and cabergoline (CAB) are dopamine agonists recently introduced for the treatment of hyperprolactinemia. In the present study, these drugs have been compared in terms of effectiveness and tolerability. Twenty patients (18 females and 2 males) with hyperprolactinemia (8 with microprolactinomas, 6 with idiopathic hyperprolactinemia and 6 with empty sella turcica syndrome) were treated with oral QUI (75 microg once daily) and CAB (0,5 mg twice weekly), in a randomized cross-over trial with placebo between both drugs. Each drug was administered for 12 weeks, separated by other 12 weeks with placebo. PRL levels decreased with both drugs at 2 or 4 weeks of starting the treatment, without differences between both drugs at weeks 4, 8 and 12. At week 12, normal PRL levels (<20 ng/ml) were attained in 90% patients with CAB and only in 75% patients with QUI (p<0.05). After discontinuation of treatment, significant increase in serum PRL was higher after QUI withdrawal than after CAB. Clinical efficacy of both treatments was similar in terms of improvement amenorrhea, oligomenorrhea, galactorrhea, and impotence. All patients completed both cycles of treatment, and the most frequent side-effects were nausea, headache and dizziness, without significant differences between CAB (30%) and QUI (55%). Our study indicates that, at the doses employed here, CAB showed a high percentage of patients with normal PRL at the end of treatment and long-lasting efficacy in the levels of PRL. Clinical response and side-effects were similar in both drugs.

Utility of fluorine-18-fluorodeoxyglucose positron emission tomography in differentiated thyroid carcinoma with negative radioiodine scans and elevated serum thyroglobulin levels

BACKGROUND

This study aimed to determine the role of fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) in the follow-up of patients who underwent total thyroidectomy and iodine-131 ((131)I) ablation therapy for differentiated thyroid cancer and presented increased thyroglobulin levels with negative (131)I and thallium-201 ((201)Tl) scans.

METHODS

Two patients with follicular carcinoma and eight with papillary tumors underwent total thyroidectomy and (131)I therapy until the (131)I scan was negative. (131)I and (201)Tl scans were performed with negative results in all cases, while serum thyroglobulin measurements were all positive with negative thyroglobulin autoantibodies. One week after the (131)I scans, all the patients underwent FDG-PET whole-body scans.

RESULTS

The FDG-PET scan detected in 4 patients, a single focal increase of FDG uptake in one lymph node metastasis (subsequently confirmed histologically); in 1 patient, multiple pathological focal uptakes in brain, neck, and chest; and in 1 patient, two mild focal uptakes in the mediastinum, close to the tracheal branch. In 2 other patients, pathological FDG uptakes in cervical spine and mediastinum were not confirmed by other imaging techniques, and in the 2 remaining patients the scan results were inconclusive. The sensitivity of FDG-PET whole-body scan for detecting metastatic thyroid cancer was 60%.

CONCLUSIONS

This study indicates that the FDG-PET whole-body scan is a useful tool in the follow-up of patients with differentiated thyroid cancer, negative (131)I and (201)Tl scans and elevated serum thyroglobulin levels. The FDG-PET scan detects metastatic disease in 60% of patients with differentiated thyroid cancer, enabling surgical therapy to be performed on accessible lesions.

Lipoprotein(a) and other lipoproteins in hypothyroid patients before and after thyroid replacement therapy

AIMS

To analyse the influence of thyroid hormones on serum lipoprotein(a) (Lp(a)) concentration and other lipid parameters, and hence potentially on coronary artery disease (CAD) risk.

METHODS

Thirty-six patients with hypothyroidism and 165 age-matched control euthyroid subjects were evaluated in a cross- sectional study, determining thyroid function tests and fasting serum lipids and lipoproteins. In a follow-up study for those hypothyroid patients the same determinations were repeated after normalization of thyroid state by levothyroxine (L-T(4)) replacement therapy. Patients needing other treatments were excluded. At baseline, patients with hypothyroidism had significantly higher levels of Lp(a), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), apolipoprotein (apo) A-I and apo B, and a higher TC/high-density lipoprotein cholesterol (HDL-C) ratio than control subjects.

RESULTS

Severity of the hypothyroid state, expressed by serum thyroid-stimulating hormone, was correlated with serum levels of Lp(a), LDL-C, and TC (r= 0.64, 0.52, 0.49, P= 0.005, P= 0.033, P= 0. 048, respectively). The pretreatment Lp(a) levels were also correlated with those of posttreatment Lp(a)(r= 0.68, P= 0.002). All patients, who presented basal Lp(a) levels higher than 30 mg/dl, showed a decrease in Lp(a) concentrations by L-T(4)therapy, and these normalized in eight cases (22.2%). Euthyroid state gave rise to a significant reduction of serum Lp(a) by 32.3%, of LDL-C by 22. 8%, of TC by 17%, of apo A-I by 9.6%, and of apo B by 9.3%. After L-T(4)therapy, CAD risk, expressed as TC/HDL-C ratio, decreased by 19.9%.

CONCLUSIONS

These results show that hypothyroidism is associated not only with elevated serum levels of LDL-C but also with elevated serum Lp(a) concentrations. Lp(a) levels may be at least partially modulated by thyroid hormone-dependent mechanisms, thus increasing the risk of developing premature atherosclerosis in hypothyroid state, that might be reduced by L-T(4)therapy.

Comparative biochemistry of CO2 fixation and the evolution of autotrophy

Carbon dioxide fixation is a polyphyletic trait that has evolved in widely separated prokaryotic branches. The three principal CO2-assimilation pathways are (i) the reductive pentose-phosphate cycle, i.e. the Calvin-Benson cycle; (ii) the reductive citric acid (or Arnon) cycle; and (iii) the net synthesis of acetyl-CoA from CO/CO2, or Wood pathway. Sequence analysis and the comparative biochemistry of these routes suggest that all of them were shaped to a considerable extent by the evolutionary recruitment of enzymes. Molecular phylogenetic trees show that the Calvin-Benson cycle was a relatively late development in the (eu)bacterial branch, suggesting that some form(s) of carbon assimilation may have been operative before chlorophyll-based photosynthesis. On the other hand, the ample phylogenetic distribution of both the Arnon and the Wood pathways does not allow us to infer which one of them is older. However, different lines of evidence, including experimental reports on the NiS/FeS-mediated C-C bond formation from CO and CH3SH are used here to argue that the first CO2-fixation route may have been a semi-enzymatic Wood-like pathway.

The role of gene duplication in the evolution of purine nucleotide salvage pathways

Purine nucleotides are formed de novo by a widespread biochemical route that may be of monophyletic origin, or are synthesized from preformed purine bases and nucleosides through different salvage pathways. Three monophyletic sets of purine salvage enzymes, each of which catalyzes mechanistically similar reactions, can be identified: (a) adenine-, xanthine-, hypoxanthine- and guanine-phosphoribosyltransferases, which are all homologous among themselves, as well as to nucleoside phosphorylases; (b) adenine deaminase, adenosine deaminase, and adenosine monophophate deaminase; and (c) guanine reductase and inosine monophosphate dehydrogenase. These homologies support the idea that substrate specificity is the outcome of gene duplication, and that the purine nucleotide salvage pathways were assembled by a patchwork process that probably took place before the divergence of the three cell domains (Bacteria, Archaea, and Eucarya). Based on the ability of adenine PRTase to catalyze the condensation of PRPP with 4-aminoimidazole-5-carboxamide (AICA), a simpler scheme of purine nucleotide biosynthesis is presented. This hypothetical route requires the prior evolution of PRPP biosynthesis. Since it has been argued that PRPP, nucleosides, and nucleotides are susceptible to hydrolysis, they are very unlikely prebiotic compounds. If this is the case, it implies that many purine salvage pathways appeared only after the evolution of phosphorylated sugar biosynthetic pathways made ribosides available.

Direct determination of diuretic drugs in urine by capillary zone electrophoresis using fluorescence detection

Four diuretic drugs banned in sport (amiloride, triamterene, bendroflumethiazide and bumetanide) have been separated by capillary zone electrophoresis (CZE) and detected using conventional fluorescence spectrometry. The effect of pH on electrophoretic parameters such as migration time, peak efficiency and peak height is discussed. Complete separation of the four drugs is achieved in less than 8 min at pH 8. No interference due to endogenous urine components is observed and thus direct urine analysis is feasible. Analytical figures of merit including precision and limits of detection are presented. Limits of detection range between 0.5 fmol for triamterene and 21.6 fmol for bumetanide.

[Papillary tumor of the pancreas diagnosed by fine-needle aspiration]

We report the case of a 48 year-old woman with an epigastric palpable mass identified by abdominal echography and computed tomography as a solid pancreatic tumor. A cytology taken by fine needle aspiration guided by computed tomography was diagnostic of papillary pancreatic tumor, which was confirmed by surgical resection. We emphasize the low frequency and good prognosis of this type of tumor after surgical resection, and the utility of image techniques and fine needle aspiration to obtain a preoperative diagnosis.

[Allergic rhinitis in the region of Mérida]

We studied the whole of 3,047 patients who consult our unit because of a presumable allergic affection. The 20% to suffer from allergic rhinitis. The most frequent clinical presentation has been rhinitis allergic seasonal followed by perennial and to extend seasonal. We have diagnosed through by prick-test, specific IgE and ocular provocation test. The ethiology more common has been the grass pollen together olive followed pollen grass from seasonal rhinitis. The mites dust from perennial rhinitis and the grass and polisensitizations to seasonal extend.