Transient uptake and storage of serotonin in developing thalamic neurons

Serotonin (5-HT) has been shown to affect the development and patterning of the mouse barrelfield. We show that the dense transient 5-HT innervation of the somatosensory, visual, and auditory cortices originates in the thalamus rather than in the raphe: 5-HT is detected in thalamocortical fibers and most 5-HT cortical labeling disappears after thalamic lesions. Thalamic neurons do not synthesize 5-HT but take up exogenous 5-HT through 5-HT high affinity uptake sites located on thalamocortical axons and terminals. 3H-5-HT injected into the cortex is retrogradely transported to thalamic neurons. In situ hybridization shows a transient expression of the genes encoding the serotonin transporter and the vesicular monoamine transporter in thalamic sensory neurons. In these glutamatergic neurons, internalized 5-HT might thus be stored and used as a "borrowed transmitter" for extraneuronal signaling or could exert an intraneuronal control on thalamic maturation.

Morphological evidence for a dopaminergic terminal field in the hippocampal formation of young and adult rat

We have visualized the dopaminergic innervation of the hippocampal formation of the rat using two morphological methods: (1) tyrosine hydroxylase immunocytochemistry on noradrenaline-depleted animals and (2) fluorescence histochemistry after the uptake and storage of dopamine on hippocampal slices in vitro. The noradrenergic hippocampal terminal fields were destroyed by neonatal neurotoxin pretreatment and the validity of the lesion checked by the absence of dopamine beta-hydroxylase immunoreactivity. As observed on early postnatal ages, dopaminergic axons reached the hippocampal formation through the fimbria and the alveus, but also through the supracallosal bundle and the ventral amygdaloid area-entorhinal cortex. The temporal (ventral and caudal) part of the hippocampal formation received the bulk of the dopaminergic innervation whereas no fibers were observed in the septal pole. Very few positive axons were visualized in the hilus of the gyrus dentatus and CA3 field, only near the temporal pole. CA1 field (stratum oriens) was innervated throughout its ventral part. The most innervated area was the ventral part--especially the deep layers--of the subiculum, in particular the prosubiculum. The dorsal part of the subiculum displayed some positive axons, although to a lesser extent. The pre- and parasubiculum contained a few positive axons. In addition, some immunoreactive axons were observed in the anterior hippocampal continuation and the indusium griseum. The ventral junction prosubiculum-CA1 field appears to be the main target area for the hippocampal dopaminergic innervation. It is interesting that the same areas are characterized by their projections to the nucleus accumbens which receives dopaminergic afferents. Thus, the hippocampostriatal projections, that represent a link between the limbic and central motor mechanisms, could be under dopaminergic influence.

Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth

The unexpectedly high flux of cosmic-ray positrons detected at Earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. We report the detection, using the High-Altitude Water Cherenkov Observatory (HAWC), of extended tera-electron volt gamma-ray emission coincident with the locations of two nearby middle-aged pulsars (Geminga and PSR B0656+14). The HAWC observations demonstrate that these pulsars are indeed local sources of accelerated leptons, but the measured tera-electron volt emission profile constrains the diffusion of particles away from these sources to be much slower than previously assumed. We demonstrate that the leptons emitted by these objects are therefore unlikely to be the origin of the excess positrons, which may have a more exotic origin.

Lipids, lipoproteins, and apoproteins in serum during infection

We studied the alterations in the concentrations of total cholesterol, high-density lipoprotein cholesterol, triglycerides, and apoproteins A and B in serum of 54 patients hospitalized for various reasons, who developed sepsis during their stay. Forty of these patients required intensive care, 14 did not. Another group of patients with the same underlying pathological conditions was used as a control. We found the following: Sepsis causes the concentrations of total cholesterol, high-density lipoprotein cholesterol, and apoproteins A and B in serum to decrease, whereas triglycerides increase. However, these changes are not related to the infectious agent, the underlying illness, or the clinical situation of the patients. The return of serum lipids to more normal concentrations parallels the recovery from sepsis. The positive correlation between the drastically decreased concentrations of high-density lipoprotein cholesterol and the severe hypoalbuminemia in these patients suggests a common pathway for these two abnormalities.

Regional and laminar distribution of the dopamine and serotonin innervation in the macaque cerebral cortex: a radioautographic study

The regional density and laminar distribution of dopamine (DA) and serotonin (5-HT) afferents were investigated in the cerebral cortex of cynomolgus monkeys using a radioautographic technique that is based on the high affinity uptake capacity of these aminergic neurons. Large vibratome sections, 50 micron thick, were incubated with [3H] DA (0.2 microM) and desipramine (5 microM) or with unlabeled norepinephrine (5 microM) and [3H] 5-HT (0.6 microM), which allowed for the specific labeling of the DA and 5-HT innervations, respectively. After fixation, these sections were dried, defatted, and radioautographed by dipping. Semiquantitative data on the DA innervation also were provided by counting [3H] DA-labeled axonal varicosities in radioautographs from 4-micron-thick sections of the slices obtained after epon embedding. The DA innervation was widespread and differed in density and laminar distribution in the agranular and granular cortices. DA afferents were densest in the anterior cingulate (area 24) and the motor areas (areas 4, 6, and supplementary motor area [SMA]). In the latter they displayed a trilaminar pattern of distribution, predominating in layers I, IIIa, and V-VI, with characteristic cluster-like formations in layer IIIa, especially in the medial part of motor areas. In the granular prefrontal (areas 46, 9, 10, 11, 12), parietal (areas 1, 2, 3, 5, 7), temporal (areas 21, 22), and posterior cingulate (area 23) cortices, DA afferents were less dense and showed a bilaminar pattern of distribution, predominating in the depth of layer I and in layers V-VI; density in layers II, III, and IV was only 20% of that in layer I. The lowest density was in the visual cortex, particularly in area 17, where the DA afferents were almost restricted to layer I. The density of 5-HT innervation was generally greater than that of DA except in the motor areas and in the anterior cingulate cortex. Region-specific laminar patterns characterized (1) motor areas where a lower density in layer III contrasted with the clusters of DA axons in the same layer; (2) the primary visual cortex (area 17), where two bands of higher density in layers III-IV and layer V outlined a poorly innervated zone in layer IVc-beta; (3) the peristriate area 18, where the 5-HT network was relatively loose but with a denser band in layer III. Thus, DA innervation of the cerebral cortex displays major differences between rodents and primates, characterized by expanded cortical targets and by a highly differentiated laminar distribution.(ABSTRACT TRUNCATED AT 400 WORDS)

Risk factors of treatment failure in community acquired pneumonia: implications for disease outcome

BACKGROUND

An inadequate response to initial empirical treatment of community acquired pneumonia (CAP) represents a challenge for clinicians and requires early identification and intervention. A study was undertaken to quantify the incidence of failure of empirical treatment in CAP, to identify risk factors for treatment failure, and to determine the implications of treatment failure on the outcome.

METHODS

A prospective multicentre cohort study was performed in 1424 hospitalised patients from 15 hospitals. Early treatment failure (<72 hours), late treatment failure, and in-hospital mortality were recorded.

RESULTS

Treatment failure occurred in 215 patients (15.1%): 134 early failure (62.3%) and 81 late failure (37.7%). The causes were infectious in 86 patients (40%), non-infectious in 34 (15.8%), and undetermined in 95. The independent risk factors associated with treatment failure in a stepwise logistic regression analysis were liver disease, pneumonia risk class, leucopenia, multilobar CAP, pleural effusion, and radiological signs of cavitation. Independent factors associated with a lower risk of treatment failure were influenza vaccination, initial treatment with fluoroquinolones, and chronic obstructive pulmonary disease (COPD). Mortality was significantly higher in patients with treatment failure (25% v 2%). Failure of empirical treatment increased the mortality of CAP 11-fold after adjustment for risk class.

CONCLUSIONS

Although these findings need to be confirmed by randomised studies, they suggest possible interventions to decrease mortality due to CAP.

Alterations of dopaminergic and noradrenergic innervations in motor cortex in Parkinson's disease

The motor areas of the cerebral cortex contain dense dopaminergic and noradrenergic innervation in humans. We looked for changes of these innervations in cases with Parkinson's disease (PD). The density of fibers immunolabeled with tyrosine hydroxylase or dopamine-beta-hydroxylase was evaluated in the primary motor, premotor, and prefrontal cortical regions in 6 cases with PD and 7 control cases. Reductions of both noradrenergic and dopaminergic cortical innervations were observed, with similar magnitudes of reduction found in the motor and prefrontal regions of the cortex. Depletion of noradrenergic innervation was diffuse, involving all cortical laminae. Depletion of dopaminergic innervation was laminar specific, with the most significant reductions in layers I and II; reductions in layers V and VI were either less marked (prefrontal cortex) or not detectable (primary motor). The results suggest the existence of two separate mesocortical dopaminergic systems in humans, with the one distributing to upper cortical layers being preferentially involved in PD.

miR-200 Inhibits lung adenocarcinoma cell invasion and metastasis by targeting Flt1/VEGFR1

The microRNA-200 (miR-200) family is part of a gene expression signature that predicts poor prognosis in lung cancer patients. In a mouse model of K-ras/p53-mutant lung adenocarcinoma, miR-200 levels are suppressed in metastasis-prone tumor cells, and forced miR-200 expression inhibits tumor growth and metastasis, but the miR-200 target genes that drive lung tumorigenesis have not been fully elucidated. Here, we scanned the genome for putative miR-200 binding sites and found them in the 3'-untranslated region (3'-UTR) of 35 genes that are amplified in human cancer. Mining of a database of resected human lung adenocarcinomas revealed that the levels of one of these genes, Flt1/VEGFR1, correlate inversely with duration of survival. Forced miR-200 expression suppressed Flt1 levels in metastasis-prone lung adenocarcinoma cells derived from K-ras/p53-mutant mice, and negatively regulated the Flt1 3'-UTR in reporter assays. Cancer-associated fibroblasts (CAFs) isolated from murine lung adenocarcinomas secreted abundant VEGF and enhanced tumor cell invasion in coculture studies. CAF-induced tumor cell invasion was abrogated by VEGF neutralization or Flt1 knockdown in tumor cells. Flt1 knockdown decreased the growth and metastasis of tumor cells in syngeneic mice. We conclude that miR-200 suppresses lung tumorigenesis by targeting Flt1.

Catecholaminergic innervation of the septal area in man: immunocytochemical study using TH and DBH antibodies

The catecholaminergic innervation of the human septal area and closely related structures has been visualized by using tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DBH) as immunocytochemical markers. TH-like immunoreactivity with no corresponding DBH labelling was considered to be indicative of dopaminergic fibers. Catecholaminergic innervation offered the following similarities to that of rodents: moderate innervation in the medial septal division, with predominant DBH immunolabelling; dense dopaminergic innervation in the lateral septal nuclei, organized in a laminar pattern; presence of dopaminergic pericellular arrangements in the dorsal septum and bed n. of the stria terminalis; clustering of dopaminergic terminals in n. accumbens associated with a medioventral zone of DBH-like immunoreactive fibers; close overlap between dopaminergic fields and acetylcholinesterase-reactive zones in both the lateral septum and the n. of the stria terminalis. Differences with the catecholaminergic septal innervation of rodents consisted of general caudal extension of the dopaminergic fields, possibly accounted for by the vertical stretching and caudal displacement of the septal nuclei in man; complementary lateromedial topography of dopaminergic and DBH-immunoreactive inputs in the n. of the stria terminalis as opposed to their dorsoventral organization in rodents; presence of TH-immunolabelled cell group in the anterior olfactory nucleus and parolfactory cortex, which seems specific for primates. Precise topographical mapping of the catecholaminergic structures in this central region of the limbic forebrain seems to be a prerequisite for accurate tissue sampling in the biochemical investigations of pathological cases and should help in the interpretation of aminergic dysfunction in a variety of human diseases.

New dopaminergic terminal fields in the motor, visual (area 18b) and retrosplenial cortex in the young and adult rat. Immunocytochemical and catecholamine histochemical analyses

New dopaminergic terminal fields have been visualized in the rat cerebral neocortex, using two morphological methods based on distinct properties of the dopaminergic system: presence of the first synthetic enzyme, tyrosine hydroxylase, and high-affinity uptake of amines. Tyrosine hydroxylase was used as an immunocytochemical marker after destruction of the cortical noradrenergic system, induced either neonatally by 6-hydroxydopamine or later on by DSP4, and controlled by the absence of dopamine beta-hydroxylase immunoreactivity. The uptake and storage of exogenous amines in tissue sections, in the presence of selective high-affinity transport inhibitors, enabled the specific visualization of the dopaminergic system with fluorescence histochemistry. A dopaminergic innervation of low density was observed along a dorsal sagittal strip which extended from the genu of corpus callosum until about 2 mm behind the splenium and encompassed several distinct cytoarchitectonic areas in the sensorimotor and visual cortex (medial and lateral agranular field, area 18b), as well as in discrete zones of the retrosplenial granular 29c,b, and agranular 29d areas. The distribution of these dopaminergic fields suggested a columnar organization. Several characteristics of the dopaminergic innervation were similar to that of the superficial anterior cingulate cortex (area 24): the laminar distribution to the superficial I-III layers, the secondarily developed varicose aspect in catecholamine fluorescence histochemistry and the delayed postnatal ingrowth in contrast with the early prenatal dopaminergic input to the prefrontal cortex. These similarities suggested that the subpopulation of dopaminergic neurons which provides projections to the anterior cingulate cortex could also contribute to the motor and visual cortex and thus play a role in sensorimotor integration. The predictive value of these results in the ascent of the phylogenetic scale are further considered.

Ultrastructural Double-Labelling Study of Dopamine Terminals and GABA-Containing Neurons in Rat Anteromedial Cerebral Cortex

The aim of this study was to identify, at the ultrastructural level, the neuronal targets of dopamine afferents to the medial prefrontal and the anterior cingulate cortex of the adult rat. Since, in addition to pyramidal neurons, the cortical neuronal population mainly consists of GABAergic nonpyramidal intrinsic neurons, the simultaneous visualization of both dopamine- and GABA-containing neurons should leave the pyramidal neurons as the only unlabelled dopamine postsynaptic target. In this context, we used a double labelling immunocytochemical procedure: a pre-embedding PAP immunostaining to visualize monoclonal conjugated-dopamine (DA) antibody, followed by postembedding immunogold staining with a polyclonal conjugated-GABA antibody. In a single section sampling of 369 DA-immunoreactive (DA-IR) varicosities observed and the GABA-containing elements, 75% of the DA-IR terminals showed no indication of any contact with a GABA neuron. Twenty-five per cent were found in nonsynaptic contiguity with a GABA-immunoreactive neuronal element: axon, dendrite or cell body. When a DA varicosity was in nonsynaptic contiguity with a neuronal perikaryon (5% of cases), this cell was GABA positive. Ten per cent of the DA varicosities were contiguous to a GABA axon, but axoaxonic synapses in either direction were never observed. A symmetrical synapse between a DA varicosity and a GABA-containing dendrite was observed only once. The other 13 DA-IR terminals exhibiting a clear synaptic junction were apposed to nonGABA-containing dendrites, spines and shafts. Triads were observed in which a DA varicosity, forming or not a symmetrical synapse, was apposed to an unlabelled dendrite already receiving a symmetrical junction from another unlabelled axon. These data confirm and extend previous results designating the pyramidal cell dendritic tree as the main synaptic target of DA cortical afferents in rat and primate cerebral cortex. However, a direct effect of dopamine on a subpopulation of intrinsic GABA neurons cannot be excluded.

Effects of ursodeoxycholic acid in patients with intrahepatic cholestasis of pregnancy

The efficacy and safety of ursodeoxycholic acid in the treatment of intrahepatic cholestasis of pregnancy was investigated in an open pilot study. Five patients received 1 gm/day of ursodeoxycholic acid during 20 days and another three patients received two identical periods of treatment separated by a 14-day interval free of the drug. Pruritus and serum levels of total bile salts and glutamic-pyruvic transaminase improved significantly during treatment with ursodeoxycholic acid. In the three patients who received two periods of treatment with ursodeoxycholic acid, pruritus and the laboratory alterations relapsed in the second week after the drug was discontinued, but they improved again when ursodeoxycholic acid was readministered. No adverse reactions were detected in the mothers or in their babies. All newborns were thriving normally during a follow-up period that lasted 5 mo after delivery. It is concluded that UDCA appears to be safe when administered in late pregnancy; its promising efficacy in the treatment of intrahepatic cholestasis of pregnancy should now be confirmed in controlled clinical trials.

The membrane transport factor TAP/p115 cycles between the Golgi and earlier secretory compartments and contains distinct domains required for its localization and function

The mammalian protein TAP/p115 and its yeast homologue Uso1p have an essential role in membrane traffic (Nakajima et al., 1991; Waters et al., 1992; Sztul et al., 1993; Rabouille et al.; 1995). To inquire into the site and mechanism of TAP/p115 action, we aimed to localize it and to identify domains required for its function. We show that in interphase cells, TAP/p115 localizes predominantly to the Golgi and to peripheral structures that represent vesicular tubular clusters (VTCs) involved in ER to Golgi transport. Using BFA/ nocodazole treatments we confirm that TAP/p115 is present on ER to Golgi transport intermediates. TAP/ p115 redistributes to peripheral structures containing ERGIC-53 during a 15 degreesC treatment, suggesting that it is a cycling protein. Within the Golgi, TAP/p115 is associated with pleiomorphic structures on the cis side of the cis-Golgi cisterna and the cis-most cisterna, but is not detected in more distal compartments of the Golgi. TAP/p115 binds the cis-Golgi protein GM130, and the COOH-terminal acidic domain of TAP/p115 is required for this interaction. TAP/p115 interaction with GM130 occurs only in the Golgi and is not required for TAP/p115 association with peripheral VTCs. To examine whether interaction with GM130 is required to recruit TAP/p115 to the Golgi, TAP/p115 mutants lacking the acidic domain were expressed and localized in transfected cells. Mutants lacking the GM130-binding domain showed normal Golgi localization, indicating that TAP/p115 is recruited to the Golgi independently of its ability to bind GM130. Such mutants were also able to associate with peripheral VTCs. Interestingly, TAP/p115 mutants containing the GM130-binding domain but lacking portions of the NH2-terminal region were restricted from the Golgi and localized to the ER. The COOH-terminal domain required for GM130 binding and the NH2-terminal region required for Golgi localization appear functionally relevant since expression of TAP/p115 mutants lacking either of these domains leads to loss of normal Golgi morphology.

The p115-interactive proteins GM130 and giantin participate in endoplasmic reticulum-Golgi traffic

The transport factor p115 is essential for endoplasmic reticulum (ER) to Golgi traffic. P115 interacts with two Golgi proteins, GM130 and giantin, suggesting that they might also participate in ER-Golgi traffic. Here, we show that peptides containing the GM130 or the giantin p115 binding domain and anti-GM130 and anti-giantin antibodies inhibit transport of vesicular stomatitis virus (VSV)-G protein to a mannosidase II-containing Golgi compartment. To determine whether p115, GM130, and giantin act together or sequentially during transport, we compared kinetics of traffic inhibition. Anti-p115, anti-GM130, and anti-giantin antibodies inhibited transport at temporally distinct steps, with the p115-requiring step before the GM130-requiring stage, and both preceding the giantin-requiring stage. Examination of the distribution of the arrested VSV-G protein showed that anti-p115 antibodies inhibited transport at the level of vesicular-tubular clusters, whereas anti-GM130 and anti-giantin antibodies inhibited after the VSV-G protein moved to the Golgi complex. Our results provide the first evidence that GM130 and giantin are required for the delivery of a cargo protein to the mannosidase II-containing Golgi compartment. These data are most consistent with a model where transport from the ER to the cis/medial-Golgi compartments requires the action of p115, GM130, and giantin in a sequential rather than coordinate mechanism.

Undergraduate research. Genomics Education Partnership

The Genomics Education Partnership offers an inclusive model for undergraduate research experiences incorporated into the academic year science curriculum, with students pooling their work to contribute to international data bases.

Biological variation of seminal parameters in healthy subjects

BACKGROUND

A study was undertaken to assess the components of biological variation of seminal parameters in healthy subjects.

METHODS

Twenty donor candidates were included in a 10-week follow-up study. Within- and between-subject biological variation, indices of individuality and heterogeneity, coefficient of reliability, critical differences, analytical goals and the lowest value observed with a <5% probability of having a true value less than the World Health Organization (1999) reference value were estimated for the following seminal parameters: concentration, total motility (WHO grades a + b + c), progressive motility (grades a + b), rapid progressive motility (grade a), sperm morphology and vitality. All analysis was performed by a single technician according to WHO 1999 guidelines for routine semen analysis. Analytical variation was assessed on different types of quality control material (frozen straws, sperm suspension, videotape, and slides) and at different (low, medium, high) quality levels.

RESULTS

The analytical variation observed depended on the quality control material used and the level of semen quality. Concentration was the semen parameter with highest within- and between-subject variation, and vitality the lowest. Indices of individuality were all <0.7, and coefficients of reliability were high (0.68-0.84). The critical difference for sequential values significant at P < 0.05 for vitality, progressive motility and morphology (34.4, 49.2 and 58.0% respectively) were lower than for concentration (77.8%).

CONCLUSIONS

The study results showed that conventional reference values for seminal parameters have little diagnostic value because of their marked individuality, though seminal parameters can be useful for assessing differences in an individual's serial results, in particular of progressive motility, morphology and vitality.

Purification and characterization of two hemolysins from Stichodactyla helianthus

Two hemolysins, Sticholysin I (St I) and Sticholysin II (St II) were purified from the sea anemone Stichodactyla helianthus combining gel filtration and ion exchange chromatography. The amino acid composition of both cytolysins was determined revealing a high proportion of glycine, lysine, tyrosine and non-polar amino acids (alanine, leucine and valine). Cysteine was not found in either polypeptide. Molecular masses of St I and St II were 19401 and 19290 Da, respectively. N-terminal sequence analysis of St I and St II showed a high homology between them suggesting they are isoforms of the same cytolysin. Compared with other sea anemone cytolysins, St I and St II contain a 22 amino acid insertion fragment also present in Eq T II/Tn C and probably in CaT I and Hm T and absent in C III, the major hemolysin previously reported in this anemone.

Epidemic transmission of enterically transmitted non-A, non-B hepatitis in Mexico, 1986-1987

Outbreaks of acute hepatitis occurred in Huitzililla and Telixtac, two rural villages 70 miles south of Mexico City, Mexico, in late 1986. The first outbreak began in Huitzililla in June of that year, 1 month after the start of the rainy season. A census revealed 94 icteric case subjects, for an attack rate of 5%; two women died. Attack rates were higher for persons older than 15 years (10%) than for younger persons. A case-control study showed that illness was highly associated with water-related factors. The second outbreak began in August 1986 in Telixtac. There were 129 case subjects, for an attack rate of 6%; one woman died. Epidemiologic findings were similar to those in Huitzililla, except that most disease transmission was not linked to unsafe water sources. None of 62 case subjects in Huitzililla and only 2 of 53 case subjects in Telixtac tested had serological evidence for recent infection with hepatitis A or B. Two of eight stool samples from Huitzililla and one of the eight stool samples from Telixtac were positive by immune electron microscopy for 32- to 34-nm viruslike particles similar to those seen in cases of enterically transmitted non-A, non-B hepatitis from Asia. To our knowledge, these investigations document for the first time the epidemic transmission of enterically transmitted non-A, non-B hepatitis virus in the Americas.

Sizing the radius of the pore formed in erythrocytes and lipid vesicles by the toxin sticholysin I from the sea anemone Stichodactyla helianthus

The radius of the pore formed by sticholysin I and II (StI, StII) in erythrocytes and sticholysin I in lipid vesicles was investigated. The rate of colloid osmotic lysis of human erythrocytes, exposed to one of the toxins in the presence of sugars of different size, was measured. The relative permeability of each sugar was derived and the pore radius estimated with the Renkin equation. The radius was similar for sticholysin I and II and was independent of the reference sugar chosen and of the toxin concentration applied. It was also the same when erythrocytes were pretreated with different toxin doses in the presence of a polyethylene glycol (PEG) large enough to prevent lysis and thereafter transferred to solutions containing oligosaccharides of different size where they did lyse at different rates. The osmometric behavior of large unilamellar vesicles (LUV) was thereafter used to estimate the toxin lesion radius in a model system. LUV transferred to a hyperosmotic solution with a certain sugar immediately shrank and then re-swelled at a rate dependent on the bilayer permeability to water and sugar. When LUV were previously permeabilized with StI, only a fraction of them, namely those not carrying pores, continued to behave as osmometers. By increasing the size of the added sugar and approaching the pore radius, the fraction of osmometric LUV increased. Relative permeabilities were derived and used to estimate a channel radius around 1.2 nm, both for sugars and for PEGs. In conclusion the sticholysin pore has a constant size independent of toxin concentration and similar in natural and artificial membranes, suggesting it has a fixed predominant structure.

CCR5 (chemokine receptor-5) DNA-polymorphism influences the severity of rheumatoid arthritis

Chemokines are critical for the inflammatory process in autoimmune diseases such as rheumatoid arthritis (RA). The chemokine receptor-5 (CCR5) mediates chemotaxis by CC-chemokines and is expressed by lymphocytes with the Th1 phenotype and monocyte/macrophages. A 32 bp deletion in the CCR5 (CCR5-delta 32 allele) abolishes receptor expression in homozygotes, while CCR5-delta 32 carriers would express less receptor than wild-type homozygotes. This polymorphism is related to the resistance to HIV-1 infection and progression towards AIDS. We hypothesized that the CCR5-delta 32 allele may modulate the severity of disease in RA. A total of 160 RA-patients (71 and 89 with severe and non-severe phenotypes, respectively) and 500 healthy individuals from the same Caucasian population (Asturias, northern Spain) were genotyped. Carriers of the CCR5-delta 32 allele were at a significantly higher frequency (P = 0.012) in non-severe compared to severe patients (17% vs 4%). Our results suggest that the CCR5-delta 32 polymorphism is a genetic marker related to the severity of RA.

Outcome of patients with acute promyelocytic leukemia failing to front-line treatment with all-trans retinoic acid and anthracycline-based chemotherapy (PETHEMA protocols LPA96 and LPA99): benefit of an early intervention

To determine prognosis of acute promyelocytic leukemia (APL) failing to front-line therapy with all-trans retinoic acid (ATRA) and anthracyclines, outcome of 52 patients (32 M/20 F; age: 37, 3-72) included in PETHEMA trials LPA96 and LPA99 who presented with either molecular failure (MOLrel, n=16) or hematological relapse (HEMrel, n=36) was analyzed. Salvage therapy consisted of ATRA and high-dose ara-C-based chemotherapy (HDAC) in most cases (83%), followed by stem-cell transplantation (autologous, 18; allogeneic, 10; syngeneic, 1). Fourteen patients with MOLrel (88%) achieved second molecular complete response (molCR), whereas 81% HEMrel patients responded to second-line treatment, with 58% molCR. After median follow-up of 45 months, four MOLrel and 18 HEMrel patients, respectively, experienced a second relapse. Outcome after MOLrel compared favorably to HEMrel, with longer survival (5-year survival: 64+/-14 vs 24+/-8%, P=0.01) and lower relapse risk (5-year relapse risk: 30+/-13 vs 64+/-9%; P=0.044). Additionally, age <or=40 and male gender were favorable variables for survival, whereas molecular response predicted longer leukemia-free survival. In conclusion, early institution of salvage therapy at molecular failure, before onset of hematological relapse, is beneficial in APL. Moreover, given the poor outcome of HEMrel managed with ATRA and HDAC, use of alternative therapeutic strategies in this setting is warranted.

Secondary bacterial peritonitis in cirrhosis: a retrospective study of clinical and analytical characteristics, diagnosis and management

BACKGROUND & AIMS

Secondary bacterial peritonitis in cirrhotic patients is an uncommon entity that has been little reported. Our aim is to analyse the frequency, clinical characteristics, treatment and prognosis of patients with secondary peritonitis in comparison to those of patients with spontaneous bacterial peritonitis (SBP).

METHODS

Retrospective analysis of 24 cirrhotic patients with secondary peritonitis compared with 106 SBP episodes.

RESULTS

Secondary peritonitis represented 4.5% of all peritonitis in cirrhotic patients. Patients with secondary peritonitis showed a significantly more severe local inflammatory response than patients with SBP. Considering diagnosis of secondary peritonitis, the sensitivity of Runyon's criteria was 66.6% and specificity 89.7%, Runyon's criteria and/or polymicrobial ascitic fluid culture were present in 95.6%, and abdominal computed tomography was diagnostic in 85% of patients in whom diagnosis was confirmed by surgery or autopsy. Mortality during hospitalization was higher in patients with secondary peritonitis than in those with SBP (16/24, 66.6% vs. 28/106, 26.4%) (p<0.001). There was a trend to lower mortality in secondary peritonitis patients who underwent surgery (7/13, 53.8%) than in those who received medical treatment only (9/11, 81.8%) (p=0.21). Considering surgically treated patients, the time between diagnostic paracentesis and surgery was shorter in survivors than in non-survivors (3.2+/-2.4 vs. 7.2+/-6.1 days, p=0.31).

CONCLUSIONS

Secondary peritonitis is an infrequent complication in cirrhotic patients but mortality is high. A low threshold of suspicion on the basis of Runyon's criteria and microbiological data, together with an aggressive approach that includes prompt abdominal computed tomography and early surgical evaluation, could improve prognosis in these patients.