The tumor suppressor PTEN is phosphorylated by the protein kinase CK2 at its C terminus. Implications for PTEN stability to proteasome-mediated degradation

The tumor suppressor phosphatase PTEN regulates cell migration, growth, and survival by dephosphorylating phosphatidylinositol second messengers and signaling phosphoproteins. PTEN possesses a C-terminal noncatalytic regulatory domain that contains multiple putative phosphorylation sites, which could play an important role in the control of its biological activity. The protein kinase CK2 phosphorylated, in a constitutive manner, a cluster of Ser/Thr residues located at the PTEN C terminus. PTEN-phosphorylated defective mutants showed decreased stability in comparison with wild type PTEN and were more rapidly degraded by the proteasome. Inhibition of PTEN phosphorylation by the CK2 inhibitor 5,6-dichloro-1-beta-d-ribofuranosyl-benzimidazole also diminished the PTEN protein content. Our results support the notion that proper phosphorylation of PTEN by CK2 is important for PTEN protein stability to proteasome-mediated degradation.

Power of outcome measurements to detect clinically significant changes in pulmonary rehabilitation of patients with COPD

STUDY OBJECTIVES

Several validated instruments are used to measure outcomes, such as exercise performance, dyspnea, and health-related quality of life after pulmonary rehabilitation (PR) in patients with COPD. However, no study has simultaneously compared the responsiveness of the most frequently used outcome measurements after PR. We designed this study to investigate the capacity of several of the most frequently used outcome measurements to detect changes after PR in a population of patients with severe COPD who qualified for lung volume reduction surgery.

DESIGN, PATIENTS, AND INTERVENTIONS

We evaluated 37 patients with severe COPD (FEV(1) < 40%) before and after 6 to 8 weeks of outpatient PR. The following frequently used tools were evaluated: the 6-min walk distance (6MWD); functional dyspnea with the Medical Research Council (MRC) scale; baseline and transitional dyspnea index (BDI/TDI); resting and 6MWD visual analog scale (VAS); quality of life with a generic tool (the Short Form-36 [SF-36]); and two disease-specific tools, the Chronic Respiratory Disease Questionnaire (CRQ) and the St. George's Respiratory Questionnaire (SGRQ).

RESULTS

After PR, mean +/- SD 6MWD increased in 33 of 37 patients (89%), from 285 +/- 97 to 343 +/- 92 m (p = 0.009). Improvements were seen also in the MRC scale in 23 of 37 patients (62%; from 2.27 +/- 0.8 to 1.86 +/- 0.6; p = 0.01); in CRQ dyspnea in 25 of 37 patients (67%; from 3.25 +/- 0.9 to 3.90 +/- 1.4; p = 0.02); in CRQ mastery in 22 of 37 patients (60%; from 4.37 +/- 1.4 to 5.14 +/- 1.3; p = 0.01); and in BDI/TDI functional in 24 of 37 patients (64%; from 1.4 +/- 0.8 to 0.7 +/- 1.1; p = 0.002). There were smaller improvements in the SGRQ in 18 of 37 patients (48%) and in the SF-36 in 19 of 37 patients (51%), but they were not statistically significant. There were good correlations between the dyspnea components of all the tools. The 6MWD change did not correlate with the changes in the other outcomes. Clinically significant changes in the values for those outcome tools were detected in > 50% of patients for the BDI/TDI, 29% of patients for the MRC scale, in 37% of patients for the 6MWD, in 48% of patients for the VAS at peak exercise, in > 50% of patients for the CRQ, and in 40% of patients for the SGRQ.

CONCLUSIONS

We conclude that the VAS peak exercise, BDI/TDI, and CRQ adequately reflect the beneficial effects of PR. The 6MWD evaluates a unique domain not related to quality of life. Due to their simplicity and sensitivity, VAS at peak exercise, 6MWD, and CRQ may be the best practical tools to evaluate responsiveness to PR.

Cerebral Venous Thrombosis Associated with COVID-19

Despite the severity of coronavirus disease 2019 (COVID-19) being more frequently related to acute respiratory distress syndrome and acute cardiac and renal injuries, thromboembolic events have been increasingly reported. We report a unique series of young patients with COVID-19 presenting with cerebral venous system thrombosis. Three patients younger than 41 years of age with confirmed Severe Acute Respiratory Syndrome coronavirus 2 (SARS-Cov-2) infection had neurologic findings related to cerebral venous thrombosis. They were admitted during the short period of 10 days between March and April 2020 and were managed in an academic institution in a large city. One patient had thrombosis in both the superficial and deep systems; another had involvement of the straight sinus, vein of Galen, and internal cerebral veins; and a third patient had thrombosis of the deep medullary veins. Two patients presented with hemorrhagic venous infarcts. The median time from COVID-19 symptoms to a thrombotic event was 7 days (range, 2-7 days). One patient was diagnosed with new-onset diabetic ketoacidosis, and another one used oral contraceptive pills. Two patients were managed with both hydroxychloroquine and azithromycin; one was treated with lopinavir-ritonavir. All patients had a fatal outcome. Severe and potentially fatal deep cerebral thrombosis may complicate the initial clinical presentation of COVID-19. We urge awareness of this atypical manifestation.

A comprehensive review of the natural history of Helicobacter pylori infection in children

Across populations of children, Helicobacter pylori prevalence ranges from under 10% to over 80%. Low prevalence occurs in the U.S., Canada, and northern and western Europe; high prevalence occurs in India, Africa, Latin America, and eastern Europe. Risk factors include socioeconomic status, household crowding, ethnicity, migration from high prevalence regions, and infection status of family members. H. pylori infection is not associated with specific symptoms in children; however, it is consistently associated with antral gastritis, although its clinical significance is unclear. Duodenal ulcers associated with H. pylori are seldom seen in children under 10 years of age. H. pylori-infected children demonstrate a chronic, macrophagic, and monocytic inflammatory cell infiltrate and a lack of neutrophils, as compared with the response observed in adults. The effect of H. pylori infection on acid secretion in children remains poorly defined. The events that occur during H. pylori colonization in children should be studied more thoroughly and should include urease activity, motility, chemotaxis, adherence, and downregulation of the host response. The importance of virulence determinants described as relevant for disease during H. pylori infection has not been extensively studied in children. Highly sensitive and specific methods for the detection of H. pylori in children are needed, especially in younger pediatric populations in which colonization is in its early phases. Criteria for the use of eradication treatment in H. pylori-infected children need to be established. Multicenter pediatric studies should focus on the identification of risk factors, which can be used as prognostic indicators for the development of gastroduodenal disease later in life.

Inhibition of cytochrome c oxidase in turnover by nitric oxide: mechanism and implications for control of respiration

Binding of nitric oxide (NO) to isolated cytochrome c oxidase in turnover was investigated by static and kinetic spectroscopic methods. These studies indicate that cytochrome c oxidase rapidly binds NO when the enzyme enters turnover. Our results show that NO binds to ferrocytochrome a3, competing with oxygen for this binding site. However, the main features of the binding process, in particular the rapid onset of inhibition, cannot be fully explained on this basis. We suggest, therefore, that there is a second binding site for NO, which has lower affinity but nevertheless plays an important role in the inhibitory process. A likely possibility is that CuB+ constitutes this second binding site. The fast onset of inhibition observed in the presence of NO, along with the dependence on the oxygen concentration, suggests that under physiological conditions, where the oxygen concentration is low, nanomolar concentrations of NO can effectively act as a regulator of the mitochondrial respiratory chain.

Cholera-like enterotoxin produced by Campylobacter jejuni. Characterisation and clinical significance

The presence and clinical significance of enterotoxins produced by Campylobacter jejuni were investigated. The supernatant of a prototype virulent strain grown in supplemented medium induced intraluminal fluid secretion in rat ileal loop but not in rabbit ileal loop or the infant mouse assay. It induced elongation and increased intracellular cyclic AMP levels in Chinese hamster ovary cells. Toxin activity was blocked by cholera antitoxin and was destroyed by heat and high or low pH; its molecular weight is in the range 10(4)-10(5) daltons. Toxin production was detected in 24 of 32 C jejuni strains from patients with diarrhoea and 1 of 6 from carriers. Antibody response to autologous C jejuni somatic antigen was investigated in 19 subjects for whom serial serum specimens were available. A fourfold rise was observed in all 10 patients with enterotoxigenic C jejuni diarrhoea, in 1 of 3 patients with non-enterotoxigenic C jejuni, and in none of the symptomless carriers of non-enterotoxigenic strains. These findings demonstrate that C jejuni produces an enterotoxin that may be important in pathogenesis of diarrhoea.

A community-based seroepidemiologic study of Helicobacter pylori infection in Mexico

A nationwide community-based survey for Helicobacter pylori infection had not been done. This study sought to determine the seroprevalence of infection in Mexico, and the socioeconomic and demographic variables that are risk factors for infection. The survey assessed 11,605 sera from a sample population representing persons ages 1-90 years from all socioeconomic and demographic levels and from all regions of Mexico. Antibodies against H. pylori were studied by ELISA using whole cell antigen. Among the findings were that 66% of the population was infected and that age was the strongest risk factor for infection. By age 1 year, 20% were infected and by age 10 years, 50% were infected. Crowding (odds ratio [OR], 1.4), low educational level (OR, 2.42), and low socioeconomic level (OR, 1.43) were risk factors for infection. Prevalence was similar in urban and in rural communities (OR, 0.95). This study is the largest community-based seroepidemiologic study of H. pylori to date.

Dyspnea in COPD: New Mechanistic Insights and Management Implications

Dyspnea is the most common symptom experienced by patients with chronic obstructive pulmonary disease (COPD). To avoid exertional dyspnea, many patients adopt a sedentary lifestyle which predictably leads to extensive skeletal muscle deconditioning, social isolation, and its negative psychological sequalae. This "dyspnea spiral" is well documented and it is no surprise that alleviation of this distressing symptom has become a key objective highlighted across COPD guidelines. In reality, this important goal is often difficult to achieve, and successful symptom management awaits a clearer understanding of the underlying mechanisms of dyspnea and how these can be therapeutically manipulated for the patients' benefit. Current theoretical constructs of the origins of activity-related dyspnea generally endorse the classical demand-capacity imbalance theory. Thus, it is believed that disruption of the normally harmonious relationship between inspiratory neural drive (IND) to breathe and the simultaneous dynamic response of the respiratory system fundamentally shapes the expression of respiratory discomfort in COPD. Sadly, the symptom of dyspnea cannot be eliminated in patients with advanced COPD with relatively fixed pathophysiological impairment. However, there is evidence that effective symptom palliation is possible for many. Interventions that reduce IND, without compromising alveolar ventilation (VA), or that improve respiratory mechanics and muscle function, or that address the affective dimension, achieve measurable benefits. A common final pathway of dyspnea relief and improved exercise tolerance across the range of therapeutic interventions (bronchodilators, exercise training, ambulatory oxygen, inspiratory muscle training, and opiate medications) is reduced neuromechanical dissociation of the respiratory system. These interventions, singly and in combination, partially restore more harmonious matching of excessive IND to ventilatory output achieved. In this review we propose, on the basis of a thorough review of the recent literature, that effective dyspnea amelioration requires combined interventions and a structured multidisciplinary approach, carefully tailored to meet the specific needs of the individual.

Viral infections of the central nervous system in Spain: a prospective study

The aim of the study was to determine the incidence of viruses causing aseptic meningitis, meningoencephalitis, and encephalitis in Spain. This was a prospective study, in collaboration with 17 Spanish hospitals, including 581 cases (CSF from all and sera from 280): meningitis (340), meningoencephalitis (91), encephalitis (76), febrile syndrome (7), other neurological disorders (32), and 35 cases without clinical information. CSF were assayed by PCR for enterovirus (EV), herpesvirus (herpes simplex [HSV], varicella-zoster [VZV], cytomegalovirus [CMV], Epstein-Barr [EBV], and human herpes virus-6 [HHV-6]), mumps (MV), Toscana virus (TOSV), adenovirus (HAdV), lymphocytic choriomeningitis virus (LCMV), West Nile virus (WNV), and rabies. Serology was undertaken when methodology was available. Amongst meningitis cases, 57.1% were characterized; EV was the most frequent (76.8%), followed by VZV (10.3%) and HSV (3.1%; HSV-1: 1.6%; HSV-2: 1.0%, HSV non-typed: 0.5%). Cases due to CMV, EBV, HHV-6, MV, TOSV, HAdV, and LCMV were also detected. For meningoencephalitis, 40.7% of cases were diagnosed, HSV-1 (43.2%) and VZV (27.0%) being the most frequent agents, while cases associated with HSV-2, EV, CMV, MV, and LCMV were also detected. For encephalitis, 27.6% of cases were caused by HSV-1 (71.4%), VZV (19.1%), or EV (9.5%). Other positive neurological syndromes included cerebellitis (EV and HAdV), seizures (HSV), demyelinating disease (HSV-1 and HHV-6), myelopathy (VZV), and polyradiculoneuritis (HSV). No rabies or WNV cases were identified. EVs are the most frequent cause of meningitis, as is HSV for meningoencephalitis and encephalitis. A significant number of cases (42.9% meningitis, 59.3% meningoencephalitis, 72.4% encephalitis) still have no etiological diagnosis.

Skin and wound infection by rapidly growing mycobacteria: an unexpected complication of liposuction and liposculpture. The Venezuelan Collaborative Infectious and Tropical Diseases Study Group

OBJECTIVE

To describe 10 patients with skin and soft tissue infection caused by rapidly growing mycobacteria after cosmetic liposuction and liposculpture.

DESIGN

Case series.

SETTINGS

Eight private geographically separate surgical facilities from a single metropolitan area.

PATIENTS

Eight patients with definite and 2 with presumptive cases of skin and soft tissue infection caused by rapidly growing mycobacteria after cosmetic surgery procedures during a 24-month period. Microorganisms were isolated from the purulent drainage obtained from wounds or fistulas in 8 cases and were identified as Mycobacterium fortuitum (3 cases) and Mycobacterium abscessus (5 cases) by routine microbiologic techniques. Acid-fast bacilli were observed on Ziehl-Neelsen-stained smears in the 2 remaining cases, but these ultimately failed to grow. In 2 of the surgical units, no apparent environmental predisposing factors were identified after thorough microbiologic environmental investigation. Clinically, all patients exhibited signs of inflammation, microabscesses, and purulent wound drainage within 24 months of abdominal and/or thigh liposuction or homologous fat tissue injection.

INTERVENTION

A combined therapeutic approach including surgical drainage, debridment, and prolonged (>3 months) treatment with combined antimicrobial agents including clarithromycin was used in all cases.

RESULTS

Nine of 10 patients responded to the combined therapeutic approach, and no evidence of infection was present during at least 12 months of follow-up.

CONCLUSION

To our knowledge, this is the first series of patients with rapidly growing mycobacterial infections to be described after liposuction and liposculpture. Rapidly growing mycobacteria should be included in the differential diagnosis of skin and soft tissue infection after cosmetic surgery.

Interaction of mitogen-activated protein kinases with the kinase interaction motif of the tyrosine phosphatase PTP-SL provides substrate specificity and retains ERK2 in the cytoplasm

ERK1 and ERK2 associate with the tyrosine phosphatase PTP-SL through a kinase interaction motif (KIM) located in the juxtamembrane region of PTP-SL. A glutathione S-transferase (GST)-PTP-SL fusion protein containing the KIM associated with ERK1 and ERK2 as well as with p38/HOG, but not with the related JNK1 kinase or with protein kinase A or C. Accordingly, ERK2 showed in vitro substrate specificity to phosphorylate GST-PTP-SL in comparison with GST-c-Jun. Furthermore, tyrosine dephosphorylation of ERK2 by the PTP-SLDeltaKIM mutant was impaired. The in vitro association of ERK1/2 with GST-PTP-SL was highly stable; however, low concentrations of nucleotides partially dissociated the ERK1/2.PTP-SL complex. Partial deletions of the KIM abrogated the association of PTP-SL with ERK1/2, indicating that KIM integrity is required for interaction. Amino acid substitution analysis revealed that Arg and Leu residues within the KIM are essential for the interaction and suggested a regulatory role for Ser(231). Finally, coexpression of PTP-SL and ERK2 in COS-7 cells resulted in the retention of ERK2 in the cytoplasm in a KIM-dependent manner. Our results demonstrate that the noncatalytic region of PTP-SL associates with mitogen-activated protein kinases with high affinity and specificity, providing a mechanism for substrate specificity, and suggest a role for PTP-SL in the regulation of mitogen-activated protein kinase translocation to the nucleus upon activation.

Digital spiral imaging

A major application of optics is imaging all types of structural, physical, chemical and biological features of matter. Techniques based on most known properties of light have been developed over the years to remotely acquire information about such features. They include the spin angular momentum, encoded in the polarization, but not yet the orbital angular momentum encoded in its spiral spectrum. Here we put forward the potential of such spiral spectra. In particular, we use several canonical examples to show how the orbital angular momentum spectra of a light beam can be used to image a variety of intrinsic and extrinsic properties encoded, e.g., in phase and amplitude gradients, dislocations or delays.

Serologic microbial associated markers can predict Crohn's disease behaviour years before disease diagnosis

BACKGROUND

Patients with Crohn's disease (CD) have serologic responses to various microbial antigens. Serologic markers are associated with aggressive forms of disease and can be detected before onset of symptoms. Their utility in pre-clinical disease or prediction of complicated disease course before diagnosis is unclear.

AIM

To evaluate the pattern of serologic anti-microbial antibodies long prior to diagnosis and the subsequent risk of complicated Crohn's disease at diagnosis.

METHODS

Sera from 100 US military personnel with Crohn's disease were obtained from the Department of Defense Serum Repository. For each patient, four samples were obtained at different time points before and around diagnosis, and were tested for 6 microbiota-directed antibodies (ASCA-IgA, ASCA-IgG, anti-OmpC, anti-CBir1, anti-A4-Fla2 and anti-FlaX). Associations between the presence and accumulation of Crohn's disease anti-microbial antibodies before diagnosis and with the later development of complications were evaluated.

RESULTS

Overall, 65 patients were positive for at least one Crohn's disease associated anti-microbial antibody in the earliest available sample, at a median of 6 years before Crohn's disease diagnosis (interquartile range, 5.6-8.2). The number of positive anti-microbial antibodies increased up to the time of Crohn's disease diagnosis. Complicated disease developed around the time of diagnosis in 24 patients. The proportion of positive antimicrobial antibodies before diagnosis was higher in patients with complicated vs. noncomplicated Crohn's disease. There was an inverse relationship between the time to first complication and the magnitude of serologic response before diagnosis.

CONCLUSION

The presence and accumulation of circulating anti-microbial antibodies years before Crohn's disease diagnosis was associated with complicated Crohn's disease at or shortly after diagnosis.

Diagnostic utility of laboratory tests in septic arthritis

BACKGROUND

Septic arthritis remains a challenging diagnosis in which the doctor often relies on laboratory tests.

OBJECTIVE

To examine the diagnostic utility of three ancillary tests--namely, white blood cells (WBC), erythrocyte sedimentation rate (ESR) and the WBC in the joint fluid (jWBC)--using likelihood ratios (LRs) and receiver operating characteristic (ROC) curves.

METHODS

This was a retrospective cohort study at the Jacobi Medical Center. Medical charts of patients who had undergone arthrocentesis were included. Patients who had "dry taps" were excluded from the study. Patients were considered to have septic arthritis if they had a positive arthrocentesis culture or operative findings. The primary outcomes of this study were the sensitivities, specificities, LR(+) and LR(-) values of the laboratory tests for septic arthritis. The performance characteristics of the laboratory tests were analysed using ROC curves.

RESULTS

156 patients were enrolled, 16 (10%) had septic arthritis. The sensitivities for WBC, ESR and jWBC were 0.75, 0.75 and 0.50, and the specificities were 0.55, 0.11 and 0.88, respectively. The LR(+) values were 1.7, 0.84 and 4.0, and the LR(-) values were 0.46, 2.4 and 0.57, respectively. In ROC curve analysis, jWBC was the best test (area under the curve (AUC) 0.75, 95% confidence interval (CI) 0.58 to 0.92), followed by WBC (AUC 0.69, 95% CI 0.57 to 0.80) and ESR (AUC 0.55, 95% CI 0.37 to 0.74). A cut-off of jWBC = 17 500 maximised sensitivity and specificity on the ROC curve.

CONCLUSIONS

jWBC was the best diagnostic test for septic arthritis, WBC and ESR were poor tests. However, no test was diagnostic, and the clinician must be careful with patients with a potential septic joint.

Cytochrome c oxidase rapidly metabolises nitric oxide to nitrite

Previous studies have shown that the addition of nitric oxide to cytochrome c oxidase rapidly generates spectral changes compatible with the formation of nitrite at the binuclear haem:copper centre. Here we directly demonstrate nitrite release following nitric oxide addition to the enzyme. The nitrite complex is kinetically inactive and the off rate for nitrite was found to be slow (0.024 min(-1)). However, the presence of reductants enhances the off rate and enables cytochrome oxidase to catalyse the rapid oxidation of nitric oxide to nitrite free in solution. This may play a major role in the mitochondrial metabolism of nitric oxide.

Site-specific examination of secondary structure and orientation determination in membrane proteins: the peptidic (13)C=(18)O group as a novel infrared probe

Detailed site-specific information can be exceptionally useful in structural studies of macromolecules in general and proteins in particular. Such information is usually obtained from spectroscopic studies using a label/probe that can reflect on particular properties of the protein. A suitable probe must not modify the native properties of the protein, and should yield interpretable structural information, as is the case with isotopic labels used by Fourier transform infrared (FTIR) spectroscopy. In particular, 1-(13)C=(18)O labels have been shown to relay site-specific secondary structure and orientational information, although limited to small peptides. The reason for this limitation is the high natural abundance of (13)C and the lack of baseline resolution between the main amide I band and the isotope-edited peak. Herein, we dramatically extend the utility of isotope edited FTIR spectroscopy to proteins of virtually any size through the use of a new 1-(13)C=(18)O label. The double-isotope label virtually eliminates any contribution from natural abundance (13)C. More importantly, the isotope-edited peak is further red-shifted (in accordance with ab initio Hartree-Fock calculations) and is now completely baseline resolved from the main amide I band. Taken together, this new label enables determination of site specific secondary structure and orientation in proteins of virtually any size. Even in small peptides 1-(13)C=(18)O is far preferable as a label in comparison to 1-(13)C=(18)O since it enables analysis without the need for any deconvolution or peak fitting procedures. Finally, the results obtained herein represent the first stage in the application of site-directed dichroism to the structural elucidation of polytopic membrane proteins.

Nitric oxide ejects electrons from the binuclear centre of cytochrome c oxidase by reacting with oxidised copper: a general mechanism for the interaction of copper proteins with nitric oxide?

Small increases in NO concentration can inhibit mitochondrial oxygen consumption by reacting at the binuclear haem a3/CuB oxygen reduction site of cytochrome c oxidase. Here we demonstrate that under normal turnover conditions NO reacts initially with the oxidised CuB rather than the haem a3. We propose that hydration of an initial Cu+/NO+ complex forms nitrite, a proton and CuB+; the latter ejects an electron from the binuclear centre and results in the observed (100 s(-1)) reduction of other electron transfer centres in the enzyme (haem a and CuA). These reactions may have implications for the interactions of NO with other copper proteins.

A common mechanism for the interaction of nitric oxide with the oxidized binuclear centre and oxygen intermediates of cytochrome c oxidase

The reactions of nitric oxide (NO) with fully oxidized cytochrome c oxidase (O) and the intermediates P and F have been investigated by optical spectroscopy, using both static and kinetic methods. The reaction of NO with O leads to a rapid (approximately 100 s-1) electron ejection from the binuclear center to cytochrome a and CuA. The reaction with the intermediates P and F leads to the depletion of these species in slower reactions, yielding the fully oxidized enzyme. The fastest optical change, however, takes place within the dead time of the stopped-flow apparatus (approximately 1 ms), and corresponds to the formation of the F intermediate (580 nm) upon reaction of NO with a species that we postulate is at the peroxide oxidation level. This species can be formulated as either Fe5+ = O CuB2+ or Fe4+ = O CuB3+, and it is spectrally distinct from the P intermediate (607 nm). All of these reactions have been rationalized through a mechanism in which NO reacts with CuB2+, generating the nitrosonium species CuB1+ NO+, which upon hydration yields nitrous acid and CuB1+. This is followed by redox equilibration of CuB with Fea/CuA or Fea3 (in which Fea and Fea3 are the iron centers of cytochromes a and a3, respectively). In agreement with this hypothesis, our results indicate that nitrite is rapidly formed within the binuclear center following the addition of NO to the three species tested (O, P, and F). This work suggests that nitrosylation at CuB2+ instead of at Fea32+ is a key event in the fast inhibition of cytochrome c oxidase by NO.

Use of a new label, (13)==(18)O, in the determination of a structural model of phospholamban in a lipid bilayer. Spatial restraints resolve the ambiguity arising from interpretations of mutagenesis data

A structural model of pentameric phospholamban (Plb) in a lipid bilayer has been derived using a combination of experimental data, obtained from ATR-FTIR site-directed dichroism, and the implementation of the resulting restraints during a molecular dynamics simulation. Plb (residues 24-52) has been synthesised incorporating a new label, 1-(13)C==(18)O, at residues 42 and 43. We have not only determined the tilt of the helices, 10(+/-6) degrees, but also the relative orientation of the transmembrane segments, with an omega angle of -32(+/-10) degrees for L42. This angle is taken as zero in the direction of the helix tilt. Plb is a simple test case where site-directed dichroism has been applied to resolve the indeterminacy arising from the mutagenesis data available. The results presented point specifically to a single structural model for Plb.

Reovirus induction of and sensitivity to beta interferon in cardiac myocyte cultures correlate with induction of myocarditis and are determined by viral core proteins

Reovirus-induced acute myocarditis in mice serves as a model to investigate non-immune-mediated mechanisms of viral myocarditis. We have used primary cardiac myocyte cultures infected with a large panel of myocarditic and nonmyocarditic reassortant reoviruses to identify determinants of viral myocarditic potential. Here, we report that while both myocarditic and nonmyocarditic reoviruses kill cardiac myocytes, viral myocarditic potential correlates with viral spread through cardiac myocyte cultures and with cumulative cell death. To address the role of secreted interferon (IFN), we added anti-IFN-alpha/beta antibody to infected cardiac myocyte cultures. Antibody benefited nonmyocarditic more than myocarditic virus spread (P < 0.001), and this benefit was associated with the reovirus M1 and L2 genes. There was no benefit for a differentiated skeletal muscle cell line culture (C2C12 cells), suggesting cell type specificity. IFN-beta induction in reovirus-infected cardiac myocyte cultures correlated with viral myocarditic potential (P = 0.006) and was associated with the reovirus M1, S2, and L2 genes. Sensitivity to the antiviral effects of IFN-alpha/beta added to cardiac myocyte cultures also correlated with viral myocarditic potential (P = 0.004) and was associated with the same reovirus genes. Several reoviruses induced IFN-beta levels discordant with their myocarditic phenotypes, and for those tested, sensitivity to IFN-alpha/beta compensated for the anomalous induction levels. Thus, the combination of induction of and sensitivity to IFN-alpha/beta is a determinant of reovirus myocarditic potential. Finally, a nonmyocarditic reovirus induced cardiac lesions in mice depleted of IFN-alpha/beta, demonstrating that IFN-alpha/beta is a determinant of reovirus-induced myocarditis. This provides the first identification of reovirus genes associated with IFN induction and sensitivity and provides the first evidence that IFN-beta can be a determinant of viral myocarditis and reovirus disease.

Increasing multidrug resistance in Helicobacter pylori strains isolated from children and adults in Mexico

The susceptibilities to three antimicrobials of 195 Helicobacter pylori strains isolated from Mexican patients is reported; 80% of the strains were resistant to metronidazole, 24% were resistant to clarithromycin, and 18% presented a transient resistance to amoxicillin. Resistance to two or more antimicrobials increased significantly from 1995 to 1997.

Helminth parasites of the eurasian badger (Meles meles L.) in Spain: a biogeographic approach

Eighty-five Eurasian badgers, Meles meles (Linnaeus, 1758), from four mainland biogeographic Spanish areas were analysed for helminths. Seventeen helminth species were found: Brachylaima sp., Euparyphium melis and Euryhelmis squamula (Trematoda), Atriotaenia incisa and Mesocestoides sp. (Cestoda) and Aelurostrongylus pridhami, Angiostrongylus vasorum, Aonchotheca putorii, Crenosoma melesi, Mastophorus muris, Molineus patens, Pearsonema plica, Physaloptera sibirica, Strongyloides sp., Trichinella sp., Uncinaria criniformis and Vigisospirura potekhina hugoti (Nematoda). In the Mediterranean area, Aonchotheca putorii, M. patens, Strongyloides sp., and U. criniformis were more prevalent in the occidental part, whereas Atriotaenia incisa and Mesocestoides sp. cestodes showed higher values on the continental slope. Metastrongyloid species (Aelurostrongylus pridhami, Angiostrongylus vasorum and Crenosoma melesi) were only detected in the occidental Mediterranean area. In contrast, spirurid species (Mastophorus muris and Vigisospirura potekhina hugoti) were almost restricted to the continental Mediterranean area. Helminthological differences between areas may result from the badger diet, abiotic factors and biocenosis present in each biogeographic area.

The gut microbiota, bile acids and their correlation in primary sclerosing cholangitis associated with inflammatory bowel disease

Background

Patients with primary sclerosing cholangitis associated with inflammatory bowel disease (PSC-IBD) have a very high risk of developing colorectal neoplasia. Alterations in the gut microbiota and/or gut bile acids could account for the increase in this risk. However, no studies have yet investigated the net result of cholestasis and a potentially altered bile acid pool interacting with a dysbiotic gut flora in the inflamed colon of PSC-IBD.

Aim

The aim of this study was to compare the gut microbiota and stool bile acid profiles, as well as and their correlation in patients with PSC-IBD and inflammatory bowel disease alone.

Methods

Thirty patients with extensive colitis (15 with concomitant primary sclerosing cholangitis) were prospectively recruited and fresh stool samples were collected. The microbiota composition in stool was profiled using bacterial 16S rRNA sequencing. Stool bile acids were assessed by high-performance liquid chromatography tandem mass spectrometry.

Results

The total stool bile acid pool was significantly reduced in PSC-IBD. Although no major differences were observed in the individual bile acid species in stool, their overall combination allowed a good separation between PSC-IBD and inflammatory bowel disease. Compared with inflammatory bowel disease alone, PSC-IBD patients demonstrated a different gut microbiota composition with enrichment in Ruminococcus and Fusobacterium genus compared with inflammatory bowel disease. At the operational taxonomic unit level major shifts were observed within the Firmicutes (73%) and Bacteroidetes phyla (17%). Specific microbiota-bile acid correlations were observed in PSC-IBD, where 12% of the operational taxonomic units strongly correlated with stool bile acids, compared with only 0.4% in non-PSC-IBD.

Conclusions

Patients with PSC-IBD had distinct microbiota and microbiota-stool bile acid correlations as compared with inflammatory bowel disease. Whether these changes are associated with, or may predispose to, an increased risk of colorectal neoplasia needs to be further clarified.

Pseudomonas aeruginosa and mortality after hospital admission for chronic obstructive pulmonary disease

BACKGROUND

Pseudomonas aeruginosa (PA) is isolated in advanced stages of chronic obstructive pulmonary disease (COPD).

OBJECTIVES

The aim of our study was to determine whether PA isolation during hospitalization for COPD exacerbation was associated with a poorer prognosis after discharge.

METHODS

We prospectively studied all patients with COPD exacerbation admitted between June 2003 and September 2004. A sputum culture was obtained at admission. Comorbidity, functional dependence, hospitalizations during the previous year, dyspnea, quality of life and other variables previously associated with mortality in COPD were studied. Spirometry and a 6-min walking test were performed 1 month after discharge. Mortality was evaluated 3 years after discharge.

RESULTS

A total of 181 patients were included in the study. Of these, 29 (16%) had PA in the sputum. The mean age was 72 years, and mean basal postbronchodilator forced expiratory volume in 1 s was 45.2% predicted (SD 14.4). The mean point value on the BODE index was 5.1 (SD 2.5). At 3 years, 17 of 29 patients (58.6%) in the PA group had died, compared to 53 of the 152 non-PA patients [34.9%; p < 0.004; hazard ratio (HR) 2.23, 95% confidence interval (CI) 1.29-3.86]. In the multivariate analysis, PA remained statistically related to posthospital mortality (p = 0.02; HR 2.2, 95% CI 1.2-4.2) after adjustment for age (p < 0.02; HR 1.04, 95% CI 1.007-1.07), BODE index (p < 0.02; HR 1.15, 95% CI 1.02-1.3) and comorbidity (p < 0.02; HR 1.24, 95% CI 1.03-1.5).

CONCLUSIONS

PA isolation in sputum in patients hospitalized for acute exacerbation of COPD is a prognostic marker of 3-year mortality. Poor prognosis is independent of other significant predictors of mortality such as BODE index, age and comorbidity, as measured by the Charlson index.