Asymptotic velocity of one dimensional diffusions with periodic drift

We consider the asymptotic behavior of the solution of one dimensional stochastic differential equations and Langevin equations in periodic backgrounds with zero average. We prove that in several such models, there is generically a non-vanishing asymptotic velocity, despite of the fact that the average of the background is zero.

Toluene mineralization by denitrification in an up flow anaerobic sludge blanket (UASB) reactor

In order to examine the effect of easily degradable substrate such as acetate on toluene mineralization by denitrification, an upflow anaerobic sludge blanket (UASB) reactor in steady state was set up. The experimentation was carried out in two stages. Initially, the reactor was fed with a carbon loading rate of 250 mg acetate-C L-1 d-1 as electron source. Nitrate loading rate (mg ) was adjusted to obtain a constant C/N ratio of 1.4. In the second stage, five toluene-C loading rates (TLR, mg toluene-C L-1 d-1), 25, 50, 75, 100 and 125, were assessed while total carbon loading rate and C/N were maintained constant at 250 mg C L-1 d-1 and 1.4, respectively. In so doing, acetate-C loading rate (mg acetate-C L-1 d-1) was gradually substituted by toluene-C. When acetate-C was the only electron source a dissimilative denitrifying process resulted as indicated by bicarbonate yield YHCO3, mg produced/mg carbon consumed) of 0.74 +/- 0.005 and denitrifying yield (YN2, mg N2 produced/mg consumed) of 0.89 +/- 0.042. The addition of different TLR did not affect the biological process as consumption carbon efficiency (CCE) values remained up to 95% +/- 3.5 and YHCO3 and YN2 values were higher than 0.71 +/- 0.03 and 0.88 +/- 0.01, respectively. Toluene mineralization by denitrification in continuous culture was successfully achieved. A simple UASB denitrifying reactor system has promising applications for complete conversion of nitrate, toluene and acetate into N2 and CO2 with a minimal sludge production.

Respiratory system of Gluconacetobacter diazotrophicus PAL5 Evidence for a cyanide-sensitive cytochrome bb and cyanide-resistant cytochrome ba quinol oxidases

In highly aerobic environments, Gluconacetobacter diazotrophicus uses a respiratory protection mechanism to preserve nitrogenase activity from deleterious oxygen. Here, the respiratory system was examined in order to ascertain the nature of the respiratory components, mainly of the cyanide sensitive and resistant pathways. The membranes of G. diazotrophicus contain Q(10), Q(9) and PQQ in a 13:1:6.6 molar ratios. UV(360 nm) photoinactivation indicated that ubiquinone is the electron acceptor for the dehydrogenases of the outer and inner faces of the membrane. Strong inhibition by rotenone and capsaicin and resistance to flavone indicated that NADH-quinone oxidoreductase is a NDH-1 type enzyme. KCN-titration revealed the presence of at least two terminal oxidases that were highly sensitive and resistant to the inhibitor. Tetrachorohydroquinol was preferentially oxidized by the KCN-sensitive oxidase. Neither the quinoprotein alcohol dehydrogenase nor its associated cytochromes c were instrumental components of the cyanide resistant pathway. CO-difference spectrum and photodissociation of heme-CO compounds suggested the presence of cytochromes b-CO and a(1)-CO adducts. Air-oxidation of cytochrome b (432 nm) was arrested by concentrations of KCN lower than 25 microM while cytochrome a(1) (442 nm) was not affected. A KCN-sensitive (I(50)=5 microM) cytochrome bb and a KCN-resistant (I(50)=450 microM) cytochrome ba quinol oxidases were separated by ion exchange chromatography.

Serum interleukin-6 levels are elevated in women with minimal-mild endometriosis

BACKGROUND

There is a need for a reliable marker of endometriosis, especially in early stages of peritoneal disease during which imaging is not effective. The use of serum interleukin (IL)-6 as a marker is controversial. To readdress the matter, patients undergoing laparoscopy were prospectively evaluated for serum IL-6 levels.

MATERIALS AND METHODS

A total of 119 women 31 years old who underwent laparoscopy were divided into groups: control patients (n = 38) with no pathologic findings; endometriosis sufferers (n = 47) with minimal-mild (MM, n = 11) or moderate-severe (MS, n = 36) endometriosis; uterine myomas (n = 13) and benign ovarian pathologies (n = 21). Blood was drawn on cycles days 5-12 and stored for subsequent analysis of IL-6 and carbohydrate antigen (CA)-125 levels.

RESULTS

Serum IL-6 levels were significantly (P = 0.002) higher in women with MM endometriosis (29.4 9.0 pg/ml) than in controls (15.7 9.3 pg/ml). When all the non-endometriosis patients were grouped together (n = 72) and serum IL-6 (17.8 12.1 pg/ml) compared with MS (n = 36; 17.6 10.3 pg/ml) and MM (n = 11; 29.4 9.0 pg/ml) endometriosis significantly (P < 0.01) higher levels in MM endometriosis were observed as compared to the other two groups. Serum Ca-125 levels were significantly (P < 0.01) elevated in MS endometriosis. A serum IL-6 threshold of 25.75 pg/ml afforded a sensitivity of 75% and specificity of 83% in the diagnosis of MM endometriosis. Sensitivity and specificity for CA-125 in the diagnosis of MS endometriosis, using 35 IU/ml as the cut-off value, were 47% and 97%, respectively.

CONCLUSIONS

IL-6 is a reliable non-invasive marker of MM endometriosis, whereas Ca-125 is of use as a marker of severe cases.

[Bone metastases]

Bone metastases represent a devastating clinical problem in the most frequent neoplasies, especially in multiple myeloma, tumours breast, prostate and lung. The consequences include pain which is refractory to conventional analgesics, osteolysis often leading to bone-marrow compression and pathological fractures, and metabolic disorders. Recent advances in diagnosis using imaging techniques as well as different biochemical techniques have helped accurate diagnosis and follow-up. The increase in survival has improved through a multimodal approach combining, inhibition of osteolysis, with prophylactic orthopaedic surgery and radiation therapy. Recent advances in basic research have determined the molecular metastatic that can predict its proclivity to metastasize. Basic research will improve understanding of the basic mechanisms and lead to the clarification of molecular targets that will help in the development of medicines capable of preventing, decreasing or blocking the metastatic process.

Effect of thyme essential oils (Thymus hyemalis and Thymus zygis) and monensin on in vitro ruminal degradation and volatile fatty acid production

The effect of the essential oils of thyme on the in vitro ruminal degradability of a barley seed/alfalfa hay substrate was studied. Two essential oils were used, one from Thymus hyemalis (TH), rich in carvacrol, and the other from Thymus zygis (TZ), rich in thymol. Four experimental treatments of in vitro degradability, using the Daisy II(200/220) incubator, were conducted including a negative control (CO), a positive control at 7.5 microg/mL of monensin (MO), and two treatments with essential oils (TH or TZ) at 1.35 microL/mL. The material was incubated at 39.5 degrees C for various lengths of time. At each time, the disappearance of dry matter, crude protein, and neutral detergent fiber was measured. Volatile fatty acids (VFAs) were determined after 48 h of incubation. CO and MO provided (p < 0.01) higher values of potential degradability (a + b) of DM than the TH and TZ treatments (72.6 and 70.8 vs 53.2 and 48.2%, respectively). Also, crude protein degradability was lowest in the essential oil treatments. The CO treatment showed the highest potential degradability of NDF. The values of VFA production obtained (p < 0.001) with CO and MO treatments were higher than those obtained with TH and TZ treatments (21.0 and 19.1 vs 11.2 and 10.1 mM). The essential oils decreased the molar proportion of propionate, increasing the acetate/propionate ratio. In conclusion, the effects of essential oils at assayed doses would not be nutritionally beneficial to the ruminal energetic metabolism.

[Analysis of oxidative stress in exhaled breath condensate from patients with severe pulmonary infections]

OBJECTIVE

Oxidative stress is an intrinsic part of the chain of events leading to inflammation of the airways caused by bacterial infection. The aim of this study was to determine whether analysis of exhaled breath condensate from patients with severe lung infections reveals changes in the redox state at the airway surface.

PATIENTS AND METHODS

The study included a total of 48 subjects divided into 4 groups: individuals without respiratory disease (n=14), patients with multilobar pneumonia (n=13), patients who had chronic obstructive pulmonary disease with superinfection (n=14), and mechanically ventilated patients with severe pneumonia (n=7). A sample of exhaled breath condensate was obtained within the first 72 hours of hospital admission and the concentrations of nitrite, nitrate, 8-isoprostane, and myeloperoxidase (MPO) were determined.

RESULTS

Significant differences in the concentrations of nitrite, 8-isoprostane, and MPO were observed between patients and individuals without respiratory disease but no differences were found between the 3 patient groups. The concentration of MPO was correlated with the concentrations of 8-isoprostane and nitrate, which were normalized to the nitrite concentration.

CONCLUSIONS

Analysis of the concentrations of 8-isoprostane and MPO in exhaled breath condensate allows assessment of oxidative stress in the airways of patients with severe lung infections.

Characterization of the satellite DNA Msat-160 from the species Chionomys nivalis (Rodentia, Arvicolinae)

The satellite DNA Msat-160 has been previously characterized in several species of the genus Microtus. Here we present the characterization of Msat-160 from Chionomys nivalis, a species with a very primitive karyotype. As in other Microtus species analyzed, C. nivalis Msat-160 is AT rich, has a monomer length of 160 bp, is undermethylated and is mainly located in all the pericentromeric heterochromatin of all autosomes and the X chromosome, but is completely absent from the Y chromosome. Hence, our results support the hypothesis that Msat-160 was initially distributed in the pericentromeric heterochromatin of all autosomes and the X chromosome. The taxonomic status of the genus Chionomys in relation to the genus Microtus is a very interesting issue, so we constructed phylogenetic dendrograms using Msat-160 sequences from several Microtus species. Although the results were not informative about this issue, the presence of Msat-160 in C. nivalis and Microtus species suggested that both genera are closely related and that this satellite DNA was present in the common ancestor. Studies of Msat-160 in different arvicoline species could help to determine the origin of this satellite and, perhaps, to establish the phylogenetic relationships of some arvicoline groups.

Recurrencia ovárica y paraaórtica de un carcinoma de cuello uterino detectada mediante PET/TC

We present the case of a 34-year-old woman diagnosed of an adenosquamous carcinoma of the uterine cervix, stage IIB of the FIGO classification (International Federation of Gynecology and Obstetrics), treated with quimiotherapy, radiotheraphy and brachytheraphy with posterior hysterectomy. A recurrence of the disease was suspected due to the progressive rise of CEA levels. A PET/CT revealed abnormal foci in both ovaries, that had been transposed to avoid lesions due to radiation, and in a left para-aortic adenopathy. The diagnosis of recurrence in these sites was confirmed by biopsy. PET with FDG (F18-fluorodeoxyglucose) is useful in the staging of primary tumour and in the detection of recurrence in uterine cervical carcinoma, with better sensitivity and specificity than CT and MRI. PET/CT improves anatomic resolution and helps to resolve the origin of unclear foci like in the case presented in which ovaries were not in their normal situation due to transposition.

[Prospective monitoring of vascular access in hemodialysis by means of a multidisciplinary team]

PURPOSE

Nowadays, expert guidelines recommend the monitoring programs of the vascular access (VA) by a multidisciplinary team.

MATERIAL AND METHOD

We present the experience over the last five years, of a prospective VA surveillance by a multidisciplinary team. The quality indicators reached are described as the associated factors for survival of the new VA.

RESULTS

Three hundred seventeen VA have been studied, 73% were arteriovenous fistulas(AVF) and the rest were polytetrafluoroethylene (PTFE) grafts at 282 patients. The main causes of dysfunctions were elevated dynamic venous pressure (42.5%) and the decreased blood flow (36.4%) with a 88% of positive predictive value. Over the 5 years there was 88 thrombosis (24 AVF and 64 PTFE grafts), that means a hazard thrombosis global rate of 0.15 access/year, which were distributed in 0.06 for AVF and 0.38 in PTFE grafts. Two hundred and one repairs of VA were done: 66.6% were elective repair after a proper review by the multidisciplinary team and the rest of them were done after the AV thrombosis happened. Urgent rescue surgeries were done in 76% of the thrombosis. 62.5% of the patients did not need a catheter after vascular access thrombosis. The complication relation with AVF and PTFE were 11.4% of the total patients hemodialysis hospitalizations. 65.2% of the VA were new access. 57% of patients were properly reviewed in the pre-dialysis unit at least once and 80% of them start haemodialysis with a mature access. The average survival (Kaplan Meier) of the new AVF was 1,575+/-55 days vs 1,087+/-102 of the PTFE grafts (p < 0.008). The survival after 1, 2 and 3 years for the AVF was 89%, 85% and 83% and for the PTFE graft 3% 67% and 51% respectively. The Cox regression has proved that the type of vascular access is the strongest factor associated to VA survival. The survival added of VA repaired due to dysfunction was 1,062 +/- 97 days vs 707 +/- 132 due to thrombosis, log rank 5.17 (p < 0,02). The increasing risk of those repaired after a thrombosis vs dysfunction is 4.2 p < 0,01.

CONCLUSIONS

The monitoring of the vascular access by a multidisciplinary team has reached:low rate of thrombosis, high elective number of repairs of the VA, high urgent rescue surgery after a thrombosis and a few number catheter needed and hospitalizations. AVF are associated with greater survival than PTFE. The VA repair due to dysfunction vs thrombosis had a greater survival as well.

Variations in genes regulating neuronal migration predict reduced prefrontal cognition in schizophrenia and bipolar subjects from mediterranean Spain: A preliminary study

Both neural development and prefrontal cortex function are known to be abnormal in schizophrenia and bipolar disorder. In order to test the hypothesis that these features may be related with genes that regulate neuronal migration, we analyzed two genomic regions: the lissencephaly critical region (chromosome 17p) encompassing the LIS1 gene and which is involved in human lissencephaly; and the genes related to the platelet-activating-factor, functionally related to LIS1, in 52 schizophrenic patients, 36 bipolar I patients and 65 normal control subjects. In addition, all patients and the 25 control subjects completed a neuropsychological battery. Thirteen (14.8%) patients showed genetic variations in either two markers related with lissencephaly or in the platelet-activating-factor receptor gene. These patients performed significantly worse in the Wisconsin Card Sorting Test-Perseverative Errors in comparison with patients with no lissencephaly critical region/platelet-activating-factor receptor variations. The presence of lissencephaly critical region/platelet-activating-factor receptor variations was parametrically related to perseverative errors, and this accounted for 17% of the variance (P = 0.0001). Finally, logistic regression showed that poor Wisconsin Card Sorting Test-Perseverative Errors performance was the only predictor of belonging to the positive lissencephaly critical region/platelet-activating-factor receptor group. These preliminary findings suggest that the variations in genes involved in neuronal migration predict the severity of the prefrontal cognitive deficits in both disorders.

Positional regulation of Pax2 expression pattern in mesencephalic and diencephalic alar plate

Regionalization of the neural tube is a fundamental event in the development of the CNS. The isthmic organizer controls the development of the mesencephalic-rhombencephalic junction by means of fibroblast growth factor 8 (Fgf8) expression. The transcription factor paired box 2 (Pax2) is expressed early in the midbrain and is later progressively restricted to the mid-hindbrain region, playing an important role in the development of the mesencephalon and the cerebellum. In this study, by implanting Fgf8-beads in the chick neural tube, we show that Fgf8 induces a heterogeneous pattern of Pax2 expression in the diencephalon. To explore the mechanisms controlling this asymmetric induction and the down-regulation of Pax2 in the anterior mesencephalon we performed antero-posterior inversions of diencephalic and/or mesencephalic neuroepithelium, with or without Fgf8-bead implantation. We show that anterior factors do not play a role in Pax2 regionalization, while posterior factors could explain these expression patterns. We conclude that the anterior mesencephalon and the diencephalon are able to retain or activate Pax2 expression under caudal influences, and to develop as a tectal structure at later developmental stages.

Catalityc effects of ruthenium and osmium spontaneous deposition on platinum surfaces toward methanol oxidation

The influence of ruthenium and osmium spontaneous deposition on polycrystalline platinum in sulfuric acid was studied by conventional electrochemical techniques. The inhibition of the hydrogen adatom voltammetric profile by the foreign adatoms was used to calculate the degree of surface coverage of ruthenium, osmium, and a mixture of both metal ions from solutions of different composition. Methanol adsorption and oxidation were compared on bare platinum, platinum/ruthenium, platinum/osmium, and ternary compounds, considering the efficiency of methanol oxidation per hydrogen adatom displaced by the foreign metal on platinum.

Patency and structural changes in cryopreserved arterial grafts used as vessel substitutes in the rat

OBJECTIVE

To evaluate the patency and structural changes that occur in the short- and mid-term when cryopreserved syngenic arterial grafts are implanted in an experimental animal model.

MATERIAL AND METHODS

Segments of iliac artery from the Spraque-Dawley rat were cryopreserved in a biological freezer according a controlled, computerized freezing protocol whereby the specimens are cooled at a rate of 1 degrees C/min. After storage at -145 degrees C in liquid N2 vapor for 30 days, the cryografts were slowly thawed. These vessels were grafted to the common iliac artery in syngenic animals. The following study groups were established: group I (GI), non-implanted cryografts; group II (GII), autografts; and group III (GIII), cryoisografts. The control group (CG) was comprised of fresh iliac arteries. The animals were sacrificed 14, 30, or 90 days post-surgery. At each of these follow-up times, graft specimens were morphologically evaluated by light and scanning and transmission electron microscopy and immunolabeling of endothelial cells (vWf). Cell damage attributed to the cryopreservation or grafting process was also determined.

RESULTS

At the time of sacrifice, graft patency was 100% for the autografts, while 26.6% of the cryoisografts showed fully occlusive thrombosis. Among other complications, two pseudoaneurysms were detected. After cryopreservation, the grafts (GI) showed patches of endothelial denudation and good cellularity of the medial layer. The intimal hyperplasia observed in autografts implanted for 14 days (GII) was significantly delayed until day 30 when the graft was cryopreserved (GIII). Cryoisografts showed general thinning of the arterial wall and degeneration accompanied by medial layer cell loss. These grafts showed most cell damage at 90 days post-implant. Expression of the vWf in all specimens showing intimal hyperplasia was confined to the outermost graft layer.

CONCLUSIONS

Cryopreservation modified the reparative response of the grafts. Owing to faster degeneration of the medial layer and a delay in the appearance of intimal hyperplasia, arterial wall thickness was reduced relative to that of the non-cryopreserved autografts. This thinning, at least in the short-term (90 days), does not seem to give rise to aneurysms owing to the generation of a neointima that stabilizes the vessel wall.

[Graft viability of patients with renal transplantation from non heart beating donors]

INTRODUCTION

Renal transplantation (RT) is currently the treatment of choice in end-stage renal disease. The Gregorio Marañón hospital performed 65 RT, 97.01 pmp, this year.

OBJECTIVE

To study the characteristics which RT patients from non-heart beating donors have in the immediate post-transplantation renogram. To know the evolution of the renal function, by renogram.

METHODS

Ten patients with NHBD graft out of 65 patients with RT were studied in the year 2003.

RESULTS

The study is made up of 10 patients with RT from NHBD, with an average timing of warm ischemia of 35 min and average timing of cool ischemia 21 h. In the post-transplantation renal function study, 9 of then showed hemodilution and one an acute tubular necrosis (ATN) pattern. In most of the cases, the study was performed the day after the RT except for one that was performed on the 4th day (1.7 +/- 1 days). Renal perfusion was conserved in every case. The renal graft maintained this type of record until post-RT day 7 (6.67 +/- 0.57 days) and evolved towards ATN after day 10 (11.65 +/- 1.5 days) and normal range on day 55 +/- 51.1 post-transplantation. All patients supported the graft, with acceptable renal function, except one of then who was treated with transplantectomy due to a renal venous thrombosis.

CONCLUSION

The renal function study showed "hemodilution" in the first post-transplantation in 90 % of the RT from NHBD. Evolution went from ATN to normality. The NHBD are adequate for transplantation, significantly shortening the waiting time for RN.

Functional neural stem cells derived from adult bone marrow

Pluripotent hematopoietic cells from adult bone marrow may give rise not only to neurons, oligodendrocytes and astrocytes after transplantation into newborn brains, but also to neural stem cells (NSC). These NSC localize to both the ventricular epithelium and subventricular zone, persist in the transplanted brain, and may generate neurospheres 1 month after transplant, which after in vitro expansion differentiate into the different neural lineages. Furthermore, the bone marrow-derived NSC differentiate in vivo into functional oligodendrocytes and neurons following demyelinating lesions, thus, demonstrating the ability of adult bone marrow progenitors to generate self-renewing, functional neural stem cells, validating this approach as an alternative source of long-lasting neural stem cells with therapeutic implications in neurodegenerative diseases.

Characterization of an EcoRI family of satellite DNA from two species of the genus Eptesicus (Vespertilionidae; Chiroptera)

We have cloned and sequenced a 321 bp band of repetitive DNA from Eptesicus fuscus and E. serotinus observed after gel electrophoresis of EcoRI digested genomic DNA in both species. Southern blot analysis of genomic DNA (from both species) digested with the same enzyme showed the existence of a ladder pattern indicating that the repetitive DNA is arrayed in tandem. The repetitive sequences have a monomer unit of 321 bp which is composed of two subunits of 160 bp, suggested by the existence of a 160 bp band in the ladder of E. fuscus and by the presence of some direct repeats found in the analysis of the consensus sequence. Analysis of the methylation status demonstrated that cytosines in CCGG sequences in this satellite DNA are methylated in E. fuscus but not in the E. serotinus. Alignment of the sequenced clones showed that several nucleotide positions are diagnostic species-specific and consequently the phylogenetic analysis grouped the monomer units from both species in two clearly separated groups.

Fabrication of low temperature macroporous hydroxyapatite scaffolds by foaming and hydrolysis of an α-TCP paste

The development of the new technologies of bone tissue engineering requires the production of bioresorbable macroporous scaffolds. Calcium phosphate cements are good candidate materials for the development of these scaffolds, as an alternative to the traditional porous sintered ceramics. In this work a novel two-step method, based in the foaming of an alpha-tricalcium phosphate (alpha-TCP) cement paste and its subsequent hydrolysis to a calcium deficient hydroxyapatite (CDHA) is presented. The foaming agent was a hydrogen peroxide (H2O2) solution, which decomposes in water and oxygen gas. CDHA foams, which combined an interconnected macroporosity with a high microporosity were obtained. The apatitic phase obtained by the hydrolysis reaction was more similar to the biologic one, in terms of chemical composition, crystallinity and specific surface than the hydroxyapatites obtained by sintering. The percentage of porosity in the foams reached a 66%. It was shown that it was possible to control the porosity, and pore size and shape by different processing parameters such as the liquid-to-powder ratio, the concentration of the H2O2 solution and the particle size of the powder.

Long-term Behaviour of Cryopreserved Arterial Grafts Versus Prosthetic Micrografts

INTRODUCTION

When a patient has no suitable vessels for use as grafts in bypass or reconstruction procedures, two of the options available are the use of a cryopreserved vessel or an expanded polytetrafluoroethylene (ePTFE) prosthesis. This study was designed to compare the long-term behaviour of these vascular substitutes.

MATERIAL AND METHODS

We established three study groups by grafting the following vessel substitutes to the iliac artery in Spraque-Dawley rats: arterial autografts (GI, n=12), cryopreserved syngenic arterial grafts (cryoisografts) (GII, n=12), and ePTFE micrografts (GIII, n=12). The animals were sacrificed 180 days after surgery, at which time the graft specimens were morphologically evaluated by light and electron microscopy, immunolabelling (ED1/alpha-actin) and morphometric analysis of the neointima.

RESULTS

At the time of sacrifice, graft patency was 100% for the autografts and cryoisografts, while 10% of the ePTFE micrografts showed fully-occlusive thrombosis. Intimal hyperplasia was observed in grafts in GI and GII; the neointima being thinner in the cryoisografts (54.36 +/- 2.26 microm) than the autografts (161.30 +/- 3.91 microm). The endothelium formed over the prosthetic micrografts was unstable, with areas of subendothelial thickening (9.37 +/- 3.18 microm). Cell loss and medial layer degeneration were observed in both GI and GII specimens, while the GIII grafts were colonised by cells on their luminal surface.

CONCLUSIONS

All three grafts show good long-term tolerance when used in an arterial setting. Following long-term implant, autografts and cryoisografts show similar alterations that give rise to the complete loss of the muscle component of the tunica media along with the formation of a stable neointima. This new layer takes on the role of the tunica media.

Typing of the eae and espB genes of attaching and effacing Escherichia coli isolates from ruminants

The types of the eae and espB genes of 178 attaching and effacing Escherichia coli (AEEC) strains isolated from diarrhoeic and healthy ruminants were investigated by PCR. Six types of the eae gene: beta (beta), gamma1 (gamma-1), gamma2 (gamma-2), epsilon (epsilon), zeta (zeta) and iota (iota), and three types of the espB gene: alpha, beta and gamma were identified in the strains studied. Moreover, three strains were negative to all the types of the eae gene tested. The types beta and gamma2 in healthy cattle, beta, gamma2 and epsilon in healthy sheep and goats, and beta in diarrhoeic calves, lambs and goat kids were the most frequent types of the eae gene among the strains studied. Although the eaebeta gene was the most prevalent among AEEC from healthy and diarrhoeic ruminants, the percentages of AEEC strains with this type found in this study in diarrhoeic animals (66.7-100%) were higher than those found in healthy animals (33.3-40.6%). Thus, these data suggest that AEEC strains with the eaebeta gene are associated with neonatal diarrhoea in ruminants. The eaegamma1, eaezeta and eaeiota genes were found in low percentages in the strains studied (4.5, 2.8 and 7.3%, respectively). All the types of the eae gene, except the type iota, showed a close correlation with the types of the espB gene: the eaebeta and eae epsilon genes with the espBbeta gene, the eaegamma2 and eaezeta genes with the espBalpha gene and the eaegamma1 gene with the espBgamma gene.

[The oncology patient in emergencies. Epidemiological data]

Oncology patients do not form a large proportion within the overall figures of an emergency service, but their clinical characteristics mean that attending to them is often complex. The elaboration of a complete clinical history, specifying the characteristics and stage of the tumoural disease, is a basic weapon for taking decisions when an emergency arises. According to the data from our centre, oncology patients account for 5% of the total of emergency cases. The most frequent type of tumour that we deal with is pulmonary, followed by breast and colon. It is often the case that these patients come to the emergency department several times in the same month and pain is the most frequent reason for consultation, although it is normal for them to mention several causes on each occasion. In a high percentage of cases the reason for the consultation is related to the disease itself, but on as many as 35% of occasions it is an intercurrent pathology. The index of admissions is high (around 50%), especially if the patient has come for a reason related to the disease. In global terms, they account for 14% of total admissions from emergencies.

Thermal inactivation of Enterococcus faecium: effect of growth temperature and physiological state of microbial cells

AIMS

To provide data on the effects on culture temperature and physiological state of cells on heat resistance of Enterococcus faecium, which may be useful in establishing pasteurization procedures.

METHODS AND RESULTS

The heat resistance of this Ent. faecium (ATCC 49624 strain) grown at different temperatures was monitored at various stages of growth. In all cases, the bacterial cells in the logarithmic phase of growth were more heat sensitive. For cells which had entered in the stationary phase, D70 values of 0.53 min at 5 degrees C, 0.74 min at 10 degrees C, 0.83 min at 20 degrees C, 0.79 min at 30 degrees C, 0.63 min at 37 degrees C, 0.48 min at 40 degrees C and 0.41 min at 45 degrees C were found. By extending the incubation times cells were more heat resistant as stationary phase progressed, although a different pattern was observed for cells grown at different temperatures. At the lower temperatures heat resistance increased progressively, reaching D70 values of 1.73 min for cells incubated at 5 degrees C for 50 days and 1.04 min for those grown at 10 degrees C for 16 days. At other temperatures assayed heat resistance became stable for late stationary phase cells, reaching D70 values of 1.05, 1.08 and 1.01 min for cultures incubated at 20, 30 and 37 degrees C. Heat resistance of cells obtained at higher temperatures, 40 and 45 degrees C, was significantly lower, with D70 values of 0.76 and 0.67 min, respectively. Neither the growth temperature nor the growth phase modified the z-values significantly.

CONCLUSIONS

D70 values obtained for Ent. faecium (ATCC 49624) varies from 0.33 to 1.73 min as a function of culture temperature and physiological state of cells. However, z values calculated were not significantly influenced by these factors. A mean value of 4.50 +/- 0.39 degrees C was found.

SIGNIFICANCE AND IMPACT OF THE STUDY

Overall results strongly suggest that, to establish heat processing conditions of pasteurized foods ensuring elimination of Ent. faecium, it is advisable to take into account the complex interaction of growth temperature and growth phase of cells acting on bacterial thermal resistance.

Nosocomial outbreak of scabies in a hospital in Spain

An outbreak of scabies occurred in a ward of a local hospital in Barbastro (Huesca, Spain), between November 2002 and January 2003. The outbreak was linked to a patient infested with mites when he was admitted to the ward on 1 November 2002. The first case had onset of symptoms on 5 November and the last one on 5 January 2003. Seventeen cases were reported: 11 healthcare workers (HCWs) and six patients.The outbreak was attributed to a delay in diagnosis, and lack of individual protection measures by caregivers. The use of short-sleeved coats is an habitual risk practice in this ward. Contact with fomites, animals, infested clothes or intimate contact with people other than their usual partners were dismissed as risk factors for the infestation. The different groups of caregivers in this ward presented a similar risk of becoming infested, and the mechanism of transmission was probably person to person contact. The implementation of specific guidelines for scabies prevention and treatment, as well as an active surveillance system, were fundamental to the control of this outbreak.

Pericentric satellite DNA sequences in Pipistrellus pipistrellus (Vespertilionidae; Chiroptera)

This paper reports the molecular and cytogenetic characterization of a HindIII family of satellite DNA in the bat species Pipistrellus pipistrellus. This satellite is organized in tandem repeats of 418 bp monomer units, and represents approximately 3% of the whole genome. The consensus sequence from five cloned monomer units has an A-T content of 62.20%. We have found differences in the ladder pattern of bands between two populations of the same species. These differences are probably because of the absence of the target sites for the HindIII enzyme in most monomer units of one population, but not in the other. Fluorescent in situ hybridization (FISH) localized the satellite DNA in the pericentromeric regions of all autosomes and the X chromosome, but it was absent from the Y chromosome. Digestion of genomic DNAs with HpaII and its isoschizomer MspI demonstrated that these repetitive DNA sequences are not methylated. Other bat species were tested for the presence of this repetitive DNA. It was absent in five Vespertilionidae and one Rhinolophidae species, indicating that it could be a species/genus specific, repetitive DNA family.

Study of Fgf15 gene expression in developing mouse brain

Fibroblast growth factor 15 (Fgf15) is a gene regulated by the expression of Otx2 in developing mouse brain (Proc Natl Acad Sci USA 97 (2000) 14388). Otx2 gene codes for a transcription factor and is fundamental for the regionalisation and development of the anterior neural plate and cephalic region of the vertebrate embryo (Development 124 (1997) 3639). In addition, the thalamic expression of Fgf15 has been recently reported under the control of Shh signalling gene, expressed in the diencephalic basal plate (Development 129 (2002) 4807). In the present work, we have analysed Fgf15 expression pattern during mouse neural development. Fgf15 appeared early in the developing neural epithelium, in domains where Fgf8 gene is also expressed and, at later stages, in specific groups of neural cells. Fgf8 is an important signalling protein with demonstrated morphogenetic activity in several embryonic regions. Fgf15 expression is localized, like Fgf8, in secondary neural tube organizers: the isthmic organizer (IsO) and the anterior neural ridge (ANR).

Use of cocaine by secondary school students in northern Spain

AIM

To describe the prevalence of cocaine and other drug use in secondary school students in Oviedo (Asturias, Northern Spain) and determine the personality features and levels of sensation seeking in cocaine users.

METHODS

2,862 secondary school students (mean age +/- SD = 15.87+/-1.48 years; 50.6% males) were interviewed during the 1998-1999 academic year. For evaluation, the World Health Organization questionnaire for drug consumption, the Eysenck Personality Questionnaire (EPQ) for adults and the Zuckerman Sensation Seeking Scale were used.

RESULTS

The prevalence of lifetime, previous year and previous month cocaine use among secondary school students was 6.1, 4.9 and 2.7%, respectively. Cocaine ranked sixth among illicit drugs ever used by this population. Once individuals had used cocaine for the first time, they were likely to use it again (44.8% of those who had ever used cocaine reported that they had done so in the previous month). Compared to students who had never used cocaine (but who may have used other substances), cocaine users had a more extensive drug abuse history. Students who had used cocaine at some point during their lifetime scored significantly higher on the EPQ psychoticism subscale and reported higher levels of sensation seeking.

CONCLUSIONS

There is a significant rate of cocaine consumption amongst secondary school students of both sexes. Cocaine users are polyconsumers of other substances, both legal and illicit. Those who consume cocaine have a different psychological profile, characterized by high sensation seeking and high levels of psychoticism.

Expression patterns and subcellular localization of the Down syndrome candidate protein MNB/DYRK1A suggest a role in late neuronal differentiation

The Minibrain (Mnb) gene belongs to a new protein kinase family, which is evolutionarily conserved, and probably plays several roles during brain development and in adulthood. In Drosophila, mnb is involved in postembryonic neurogenesis and in learning/memory. In humans, MNB has been mapped within the Down syndrome critical region of chromosome 21 and is overexpressed in the Down syndrome embryonic brain. It has been widely proposed that MNB is involved in the neurobiological alterations associated with Down syndrome. Nevertheless, little is known about the functional role that MNB plays in vertebrate brain development. We have recently shown [Hämmerle et al. (2002) Dev. Biol., 246, 259-273] that in early vertebrate embryos, Mnb is transiently expressed in neural progenitor cells during the transition from proliferating to neurogenic divisions. Here we have studied in detail a second wave of Mnb expression, which takes place in the brain of intermediate and late vertebrate embryos. In these stages, MNB seems to be restricted to certain populations of neurons, as no consistent expression was detected in astroglial or oligodendroglial cells. Interestingly, MNB expression takes place at the time of dendritic tree differentiation and is initiated by a transient translocation from the cytoplasm to the nucleus. Afterwards, MNB protein is transported to the growing dendritic tree, where it colocalizes with Dynamin 1, a putative substrate of MNB kinases. We propose that MNB kinase is involved in the signalling mechanisms that regulate dendrite differentiation. This functional role helps to build a new hypothesis for the implication of MNB/DYRK1A in the developmental aetiology of Down syndrome neuropathologies.

Repeated DNA sequences in the microbat species Miniopterus schreibersi (Vespertilionidae; Chiroptera)

Repetitive DNA sequences represent a substantial component of eukaryotic genomes. These sequences have been described and characterized in many mammalian species. However, little information about repetitive DNA sequences is available in bat species. Here we describe an EcoRI family of repetitive DNA sequences present in the species Miniopterus schreibersi. These repetitive sequences are 57.85%, A-T rich, organized in tandem, and with a monomer unit length of 904 bp. Methylation analysis using the isoesquizomer pair MspI and HpaII indicates that the cytosines present in the sequences CCGG are partially methylated. Furthermore, Southern blot analysis demonstrated that these DNA sequences are absent in the genomes of four related microbat species and suggest that it could be specific to the M. schreibersi genome.

Verotoxin-producing Escherichia coli (VTEC), enteropathogenic E. coli (EPEC) and necrotoxigenic E. coli (NTEC) isolated from healthy cattle in Spain

AIMS

To determine the prevalence and characteristics of verotoxigenic Escherichia coli (VTEC), enteropathogenic E. coli (EPEC) and necrotoxigenic E. coli (NTEC) in healthy cattle.

METHODS AND RESULTS

Faecal samples from 412 healthy cattle were screened for the presence of VTEC, EPEC and NTEC. Four isolates from each sample were studied. VTEC, EPEC and NTEC were isolated in 8.7%, 8.2% and 9.9% of the animals, respectively. VTEC and NTEC were isolated more frequently from calves and heifers than from adults. Seventy (4.2%), 69 (4.2%) and 74 (4.5%) of the 1648 E. coli isolates were VTEC, EPEC and NTEC, respectively. Seventeen (24.3%) of the VTEC strains were eae-positive. Thirty-six (51.4%) of VTEC strains belonged to E. coli serogroups associated with haemorrhagic colitis and haemolytic uraemic syndrome in humans. The serogroups most prevalent among the EPEC strains were O10, O26, O71, O145 and O156.

CONCLUSIONS

Healthy cattle are a reservoir of VTEC, EPEC and NTEC.

SIGNIFICANCE AND IMPACT OF THE STUDY

Although most of the VTEC strains were eae-negative, a high percentage of VTEC strains belonged to serogroups associated with severe disease in humans.

Clips for the prevention and treatment of postpolypectomy bleeding (hemoclips in polypectomy)

INTRODUCTION

The most accurate method for the prevention and treatment of complications after polypectomy has not been well defined. The prophylactic use of hemoclips may reduce the risk of bleeding, mainly in pedunculated big polyps.

OBJECTIVE

To evaluate the accuracy of hemoclips in the prophylaxis and treatment of bleeding after endoscopic polypectomy.

MATERIAL AND METHODS

Retrospective study of 223 consecutive endoscopic polypectomies performed in our Endoscopy Unit between january and october 2001. Hemoclips were routinely used only for large polyps (15 to 40 mm); all of them were located in the colon except one, a gastric polyp.

RESULTS

From a total of 223 polypectomies (215 patients), hemoclips were used for 34 (15.2%), in 30 of them just before and in 4 just after polypectomy. When used prophylactically no complication was observed, except one mild bleeding episode (3.3%) that stopped with the placing of a second hemoclip. The therapeutic clipping (4 polypectomies) induced immediate haemostasis in all cases.

CONCLUSIONS

The prophylactic use of hemoclips is associated with a very low risk of bleeding after endoscopic resection of big polyps. Therapeutic clipping is an effective measure for polypectomy-related bleeding.

Mnb/Dyrk1A is transiently expressed and asymmetrically segregated in neural progenitor cells at the transition to neurogenic divisions

The Minibrain (Mnb) gene encodes a new family of protein kinases that is evolutionarily conserved from insects to humans. In Drosophila, Mnb is involved in postembryonic neurogenesis. In humans, MNB has been mapped within the Down's Syndrome (DS) critical region of chromosome 21 and is overexpressed in DS embryonic brain. In order to study a possible role of Mnb on the neurogenesis of vertebrate brain, we have cloned the chick Mnb orthologue and studied the spatiotemporal expression of Mnb in proliferative regions of the nervous system. In early embryos, Mnb is expressed before the onset of neurogenesis in the three general locations where neuronal precursors are originated: neuroepithelia of the neural tube, neural crest, and cranial placodes. Mnb is transiently expressed during a single cell cycle of neuroepithelial progenitor (NEP) cells. Mnb expression precedes and widely overlaps with the expression of Tis21, an antiproliferative gene that has been reported to be expressed in the onset of neurogenic divisions of NEP cells. Mnb transcription begins in mitosis, continues during G(1), and stops before S-phase. Very interestingly, we have found that Mnb mRNA is asymmetrically localized during the mitosis of these cells and inherited by one of the sibling cells after division. We propose that Mnb defines a transition step between proliferating and neurogenic divisions of NEP cells.

Highly repeated DNA sequences in three species of the genus Pteropus (Megachiroptera, Mammalia)

Bat genomes are characterised by an A-T richness and by a small C-value compared with other mammalian groups. It has been suggested that the small C-value is mainly due to the lack of repetitive DNA sequences. However, little information about repetitive DNA sequences in this mammalian group is available at the molecular level. Here we describe a PstI family of repetitive DNA sequences present in three species of the genus Pteropus. These repetitive sequences are 54.97% G-C rich, organised in tandem and with a unit length of 744 bp. Methylation analysis indicates that some of the CCGG target sites present in these repetitive DNA sequences have methylated cytosines and that there are small differences in the methylation pattern between species. Several features of this family of repetitive sequences suggest that they evolved by concerted evolution.

The early steps of oligodendrogenesis: insights from the study of the plp lineage in the brain of chicks and rodents

Oligodendrocytes are the myelin-forming cells of the central nervous system. Over the last decade, their development in the embryonic brain and spinal cord has been documented following the discovery of early oligodendroglial markers. These early expressed oligodendroglial genes nevertheless show differences in their spatiotemporal pattern of expression and it is not yet clear if their expression is linked in a linear way. This review highlights the common themes underlying the spatiotemporal aspects of oligodendrogenesis in chick and rodent brain and discusses some recent advances in the knowledge of the cell lineage expressing plp, one of the early oligodendroglial genes. We suggest a model of oligodendroglial commitment whereby definitive oligodendroglial progenitor formation is preceded by a primitive neuroglial progenitor stage and whereby different oligodendrocyte lineages might segregate from either plp-positive or plp-negative primitive progenitor cells.

Analysis of Fgf15 expression pattern in the mouse neural tube

The dynamic process of neural tube regionalization in vertebrates is regulated by the expression of developmental genes which appear in characteristic patterns at neuroepithelial transversal domains, which are called secondary organizers. The molecular code present in these neuroepithelial organizers controls the generation of morphogenetic signals that induce and maintain regional characteristics in the surrounding neuroepithelium. The product of the Fgf8 gene is a secreted protein that has been demonstrated to be the key molecule for the isthmic organizer and is also expressed in two other organizer regions: the zona limitans and the anterior neural ridge. Here we analyze the expression of Fgf15 at different stages of mouse development in relation to Fgf8 and Otx2 expression patterns.