Acceleration and transport of relativistic electrons in the jets of the microquasar SS 433

SS 433 is a microquasar, a stellar binary system that launches collimated relativistic jets. We observed SS 433 in gamma rays using the High Energy Stereoscopic System (H.E.S.S.) and found an energy-dependent shift in the apparent position of the gamma-ray emission from the parsec-scale jets. These observations trace the energetic electron population and indicate that inverse Compton scattering is the emission mechanism of the gamma rays. Our modeling of the energy-dependent gamma-ray morphology constrains the location of particle acceleration and requires an abrupt deceleration of the jet flow. We infer the presence of shocks on either side of the binary system, at distances of 25 to 30 parsecs, and that self-collimation of the precessing jets forms the shocks, which then efficiently accelerate electrons.

Discovery of Gamma Rays from the Quiescent Sun with HAWC

We report the first detection of a TeV γ-ray flux from the solar disk (6.3σ), based on 6.1 years of data from the High Altitude Water Cherenkov (HAWC) observatory. The 0.5-2.6 TeV spectrum is well fit by a power law, dN/dE=A(E/1  TeV)^{-γ}, with A=(1.6±0.3)×10^{-12}  TeV^{-1} cm^{-2} s^{-1} and γ=3.62±0.14. The flux shows a strong indication of anticorrelation with solar activity. These results extend the bright, hard GeV emission from the disk observed with Fermi-LAT, seemingly due to hadronic Galactic cosmic rays showering on nuclei in the solar atmosphere. However, current theoretical models are unable to explain the details of how solar magnetic fields shape these interactions. HAWC's TeV detection thus deepens the mysteries of the solar-disk emission.

Time-resolved hadronic particle acceleration in the recurrent nova RS Ophiuchi

Recurrent novae are repeating thermonuclear explosions in the outer layers of white dwarfs, due to the accretion of fresh material from a binary companion. The shock generated when ejected material slams into the companion star's wind can accelerate particles. We report very-high-energy (VHE, [Formula: see text]) gamma rays from the recurrent nova RS Ophiuchi, up to a month after its 2021 outburst, observed using the High Energy Stereoscopic System. The VHE emission has a similar temporal profile to lower-energy GeV emission, indicating a common origin, with a two-day delay in peak flux. These observations constrain models of time-dependent particle energization, favoring a hadronic emission scenario over the leptonic alternative. Shocks in dense winds provide favorable environments for efficient acceleration of cosmic-rays to very high energies.

Revealing x-ray and gamma ray temporal and spectral similarities in the GRB 190829A afterglow

Gamma-ray bursts (GRBs), which are bright flashes of gamma rays from extragalactic sources followed by fading afterglow emission, are associated with stellar core collapse events. We report the detection of very-high-energy (VHE) gamma rays from the afterglow of GRB 190829A, between 4 and 56 hours after the trigger, using the High Energy Stereoscopic System (H.E.S.S.). The low luminosity and redshift of GRB 190829A reduce both internal and external absorption, allowing determination of its intrinsic energy spectrum. Between energies of 0.18 and 3.3 tera-electron volts, this spectrum is described by a power law with photon index of 2.07 ± 0.09, similar to the x-ray spectrum. The x-ray and VHE gamma-ray light curves also show similar decay profiles. These similar characteristics in the x-ray and gamma-ray bands challenge GRB afterglow emission scenarios.

Humanized C3 Mouse: A Novel Accelerated Model of C3 Glomerulopathy

BACKGROUND

C3 glomerulopathy (C3G) is characterized by the alternative-pathway (AP) hyperactivation induced by nephritic factors or complement gene mutations. Mice deficient in complement factor H (CFH) are a classic C3G model, with kidney disease that requires several months to progress to renal failure. Novel C3G models can further contribute to understanding the mechanism behind this disease and developing therapeutic approaches.

METHODS

A novel, rapidly progressing, severe, murine model of C3G was developed by replacing the mouse C3 gene with the human C3 homolog using VelociGene technology. Functional, histologic, molecular, and pharmacologic assays characterize the presentation of renal disease and enable useful pharmacologic interventions in the humanized C3 (C3^hu/hu) mice.

RESULTS

The C3^hu/hu mice exhibit increased morbidity early in life and die by about 5-6 months of age. The C3^hu/hu mice display elevated biomarkers of kidney dysfunction, glomerulosclerosis, C3/C5b-9 deposition, and reduced circulating C3 compared with wild-type mice. Administration of a C5-blocking mAb improved survival rate and offered functional and histopathologic benefits. Blockade of AP activation by anti-C3b or CFB mAbs also extended survival and preserved kidney function.

CONCLUSIONS

The C3^hu/hu mice are a useful model for C3G because they share many pathologic features consistent with the human disease. The C3G phenotype in C3^hu/hu mice may originate from a dysregulated interaction of human C3 protein with multiple mouse complement proteins, leading to unregulated C3 activation via AP. The accelerated disease course in C3^hu/hu mice may further enable preclinical studies to assess and validate new therapeutics for C3G.

Constraints on Lorentz Invariance Violation from HAWC Observations of Gamma Rays above 100 TeV

Because of the high energies and long distances to the sources, astrophysical observations provide a unique opportunity to test possible signatures of Lorentz invariance violation (LIV). Superluminal LIV enables the decay of photons at high energy. The high altitude water Cherenkov (HAWC) observatory is among the most sensitive gamma-ray instruments currently operating above 10 TeV. HAWC finds evidence of 100 TeV photon emission from at least four astrophysical sources. These observations exclude, for the strongest of the limits set, the LIV energy scale to 2.2×10^{31}  eV, over 1800 times the Planck energy and an improvement of 1 to 2 orders of magnitude over previous limits.

Multiple Galactic Sources with Emission Above 56 TeV Detected by HAWC

We present the first catalog of gamma-ray sources emitting above 56 and 100 TeV with data from the High Altitude Water Cherenkov Observatory, a wide field-of-view observatory capable of detecting gamma rays up to a few hundred TeV. Nine sources are observed above 56 TeV, all of which are likely galactic in origin. Three sources continue emitting past 100 TeV, making this the highest-energy gamma-ray source catalog to date. We report the integral flux of each of these objects. We also report spectra for three highest-energy sources and discuss the possibility that they are PeVatrons.

Publisher Correction: Very-high-energy particle acceleration powered by the jets of the microquasar SS 433

In this Letter, owing to a production error, the penultimate version of the PDF was published. The HTML version was always correct. The PDF has been corrected online.

Multimessenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A

Previous detections of individual astrophysical sources of neutrinos are limited to the Sun and the supernova 1987A, whereas the origins of the diffuse flux of high-energy cosmic neutrinos remain unidentified. On 22 September 2017, we detected a high-energy neutrino, IceCube-170922A, with an energy of ~290 tera–electron volts. Its arrival direction was consistent with the location of a known γ-ray blazar, TXS 0506+056, observed to be in a flaring state. An extensive multiwavelength campaign followed, ranging from radio frequencies to γ-rays. These observations characterize the variability and energetics of the blazar and include the detection of TXS 0506+056 in very-high-energy γ-rays. This observation of a neutrino in spatial coincidence with a γ-ray–emitting blazar during an active phase suggests that blazars may be a source of high-energy neutrinos.

Search for γ-Ray Line Signals from Dark Matter Annihilations in the Inner Galactic Halo from 10 Years of Observations with H.E.S.S

Spectral lines are among the most powerful signatures for dark matter (DM) annihilation searches in very-high-energy γ rays. The central region of the Milky Way halo is one of the most promising targets given its large amount of DM and proximity to Earth. We report on a search for a monoenergetic spectral line from self-annihilations of DM particles in the energy range from 300 GeV to 70 TeV using a two-dimensional maximum likelihood method taking advantage of both the spectral and spatial features of the signal versus background. The analysis makes use of Galactic center observations accumulated over ten years (2004-2014) with the H.E.S.S. array of ground-based Cherenkov telescopes. No significant γ-ray excess above the background is found. We derive upper limits on the annihilation cross section ⟨σv⟩ for monoenergetic DM lines at the level of 4×10^{-28}  cm^{3} s^{-1} at 1 TeV, assuming an Einasto DM profile for the Milky Way halo. For a DM mass of 1 TeV, they improve over the previous ones by a factor of 6. The present constraints are the strongest obtained so far for DM particles in the mass range 300 GeV-70 TeV. Ground-based γ-ray observations have reached sufficient sensitivity to explore relevant velocity-averaged cross sections for DM annihilation into two γ-ray photons at the level expected from the thermal relic density for TeV DM particles.

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.

Direct-acting antiviral treatment against hepatitis C virus infection in HIV-Infected patients - "En route for eradication"?

OBJECTIVES

Direct-Acting Antivirals (DAAs) opened a new era in HCV treatment. We report the impact of HCV treatment in French HIV-HCV coinfected patients.

METHODS

All HIV-HCV patients from the Dat'AIDS cohort followed between 2012 and 2015 were included. HCV status was defined yearly as naive, spontaneous cure, sustained virological response (SVR12), failure or reinfection.

RESULTS

Among 32,945 HIV-infected patients, 15.2% were positive for anti-HCV antibodies. From 2012 to 2015, HCV incidence rate increased from 0.35%PY to 0.69%PY in MSM, while median incidence was 0.08%PY in other patients. Median reinfection rate was 2.56%PY in MSM and 0.22%PY in other patients. HCV treatment initiation rate rose from 8.2% in 2012 to 29.6% (48.0% in pre-treated patients vs 22.6% in naïve patients). SVR12 rate increased from 68.7% to 95.2%. By the end of 2015, 62.7% of the patients were cured either spontaneously or following SVR.

CONCLUSIONS

HCV treatment dramatically increased in HIV-HCV patients in France from 2012 to 2015 resulting in HCV cure in nearly two-thirds of the patients in this cohort. Combined with a declining HCV prevalence, the prevalence of active HCV infection among HIV patients will drastically decrease in the forthcoming years.

H.E.S.S. Limits on Linelike Dark Matter Signatures in the 100 GeV to 2 TeV Energy Range Close to the Galactic Center

A search for dark matter linelike signals iss performed in the vicinity of the Galactic Center by the H.E.S.S. experiment on observational data taken in 2014. An unbinned likelihood analysis iss developed to improve the sensitivity to linelike signals. The upgraded analysis along with newer data extend the energy coverage of the previous measurement down to 100 GeV. The 18 h of data collected with the H.E.S.S. array allow one to rule out at 95% C.L. the presence of a 130 GeV line (at l=-1.5°, b=0° and for a dark matter profile centered at this location) previously reported in Fermi-LAT data. This new analysis overlaps significantly in energy with previous Fermi-LAT and H.E.S.S.

RESULTS

No significant excess associated with dark matter annihilations was found in the energy range of 100 GeV to 2 TeV and upper limits on the gamma-ray flux and the velocity weighted annihilation cross section are derived adopting an Einasto dark matter halo profile. Expected limits for present and future large statistics H.E.S.S. observations are also given.

Search for Dark Matter Annihilations towards the Inner Galactic Halo from 10 Years of Observations with H.E.S.S

The inner region of the Milky Way halo harbors a large amount of dark matter (DM). Given its proximity, it is one of the most promising targets to look for DM. We report on a search for the annihilations of DM particles using γ-ray observations towards the inner 300 pc of the Milky Way, with the H.E.S.S. array of ground-based Cherenkov telescopes. The analysis is based on a 2D maximum likelihood method using Galactic Center (GC) data accumulated by H.E.S.S. over the last 10 years (2004-2014), and does not show any significant γ-ray signal above background. Assuming Einasto and Navarro-Frenk-White DM density profiles at the GC, we derive upper limits on the annihilation cross section ⟨σv⟩. These constraints are the strongest obtained so far in the TeV DM mass range and improve upon previous limits by a factor 5. For the Einasto profile, the constraints reach ⟨σv⟩ values of 6×10^{-26}  cm^{3} s^{-1} in the W^{+}W^{-} channel for a DM particle mass of 1.5 TeV, and 2×10^{-26}  cm^{3} s^{-1} in the τ^{+}τ^{-} channel for a 1 TeV mass. For the first time, ground-based γ-ray observations have reached sufficient sensitivity to probe ⟨σv⟩ values expected from the thermal relic density for TeV DM particles.

Constraints on an annihilation signal from a core of constant dark matter density around the milky way center with H.E.S.S

An annihilation signal of dark matter is searched for from the central region of the Milky Way. Data acquired in dedicated on-off observations of the Galactic center region with H.E.S.S. are analyzed for this purpose. No significant signal is found in a total of ∼9  h of on-off observations. Upper limits on the velocity averaged cross section, ⟨σv⟩, for the annihilation of dark matter particles with masses in the range of ∼300  GeV to ∼10  TeV are derived. In contrast to previous constraints derived from observations of the Galactic center region, the constraints that are derived here apply also under the assumption of a central core of constant dark matter density around the center of the Galaxy. Values of ⟨σv⟩ that are larger than 3×10^{-24}  cm^{3}/s are excluded for dark matter particles with masses between ∼1 and ∼4  TeV at 95% C.L. if the radius of the central dark matter density core does not exceed 500 pc. This is the strongest constraint that is derived on ⟨σv⟩ for annihilating TeV mass dark matter without the assumption of a centrally cusped dark matter density distribution in the search region.

Search for photon-linelike signatures from dark matter annihilations with H.E.S.S

Gamma-ray line signatures can be expected in the very-high-energy (E(γ)>100 GeV) domain due to self-annihilation or decay of dark matter (DM) particles in space. Such a signal would be readily distinguishable from astrophysical γ-ray sources that in most cases produce continuous spectra that span over several orders of magnitude in energy. Using data collected with the H.E.S.S. γ-ray instrument, upper limits on linelike emission are obtained in the energy range between ∼ 500 GeV and ∼ 25 TeV for the central part of the Milky Way halo and for extragalactic observations, complementing recent limits obtained with the Fermi-LAT instrument at lower energies. No statistically significant signal could be found. For monochromatic γ-ray line emission, flux limits of (2 × 10(-7) -2 × 10(-5)) m(-2) s(-1) sr(-1) and (1 × 10(-8) -2 × 10(-6)) m(-2) s(-1)sr(-1) are obtained for the central part of the Milky Way halo and extragalactic observations, respectively. For a DM particle mass of 1 TeV, limits on the velocity-averaged DM annihilation cross section ⟨σv⟩(χχ → γγ) reach ∼ 10(-27) cm(3)s(-1), based on the Einasto parametrization of the Galactic DM halo density profile.

Critical role of Bcl11b in suppressor function of T regulatory cells and prevention of inflammatory bowel disease

Dysregulated CD4(+) T cell responses and alterations in T regulatory cells (T(reg) cells) play a critical role in autoimmune diseases, including inflammatory bowel disease (IBD). The current study demonstrates that removal of Bcl11b at the double-positive stage of T cell development or only in T(reg) cells causes IBD because of proinflammatory cytokine-producing CD4(+) T cells infiltrating the colon. Provision of WT T(reg) cells prevented IBD, demonstrating that alterations in T(reg) cells are responsible for the disease. Furthermore, Bcl11b-deficient T(reg) cells had reduced suppressor activity with altered gene expression profiles, including reduced expression of the genes encoding Foxp3 and IL-10, and up-regulation of genes encoding proinflammatory cytokines. Additionally, the absence of Bcl11b altered the induction of Foxp3 expression and reduced the generation of induced T(reg) cells (iT(reg) cells) after Tgf-β treatment of conventional CD4(+) T cells. Bcl11b bound to Foxp3 and IL-10 promoters, as well as to critical conserved noncoding sequences within the Foxp3 and IL-10 loci, and mutating the Bcl11b binding site in the Foxp3 promoter reduced expression of a luciferase reporter gene. These experiments demonstrate that Bcl11b is indispensable for T(reg) suppressor function and for maintenance of optimal Foxp3 and IL-10 gene expression, as well as for the induction of Foxp3 expression in conventional CD4(+) T cells in response to Tgf-β and generation of iT(reg) cells.

Search for a dark matter annihilation signal from the galactic center halo with H.E.S.S

A search for a very-high-energy (VHE; ≥100  GeV) γ-ray signal from self-annihilating particle dark matter (DM) is performed towards a region of projected distance r∼45-150  pc from the Galactic center. The background-subtracted γ-ray spectrum measured with the High Energy Stereoscopic System (H.E.S.S.) γ-ray instrument in the energy range between 300 GeV and 30 TeV shows no hint of a residual γ-ray flux. Assuming conventional Navarro-Frenk-White and Einasto density profiles, limits are derived on the velocity-weighted annihilation cross section (σv) as a function of the DM particle mass. These are among the best reported so far for this energy range and in particular differ only little between the chosen density profile parametrizations. In particular, for the DM particle mass of ∼1  TeV, values for (σv) above 3×10(-25)  cm(3) s(-1) are excluded for the Einasto density profile.

The clinical variability of maternally inherited diabetes and deafness is associated with the degree of heteroplasmy in blood leukocytes

CONTEXT

Maternally inherited diabetes and deafness (MIDD) is a rare form of diabetes with a matrilineal transmission, sensorineural hearing loss, and macular pattern dystrophy due to an A to G transition at position 3243 of mitochondrial DNA (mtDNA) (m.3243A>G). The phenotypic heterogeneity of MIDD may be the consequence of different levels of mutated mtDNA among mitochondria in a given tissue.

OBJECTIVE

The aim of the present study was thus to ascertain the correlation between the severity of the phenotype in patients with MIDD and the level of heteroplasmy in the blood leukocytes.

PARTICIPANTS

The GEDIAM prospective multicenter register was initiated in 1995. Eighty-nine Europid patients from this register, with MIDD and the mtDNA 3243A>G mutation, were included. Patients with MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) or with mitochondrial diabetes related to other mutations or to deletions of mtDNA were excluded.

RESULTS

A significant negative correlation was found between levels of heteroplasmy and age of the patients at the time of sampling for molecular analysis, age at the diagnosis of diabetes, and body mass index. After adjustment for age at sampling for molecular study and gender, the correlation between heteroplasmy levels and age at the diagnosis of diabetes was no more significant. The two other correlations remained significant. A significant positive correlation between levels of heteroplasmy and HbA(1c) was also found and remained significant after adjustment for age at molecular sampling and gender.

CONCLUSIONS

These results support the hypothesis that heteroplasmy levels are at least one of the determinants of the severity of the phenotype in MIDD.

Discovery of localized regions of excess 10-TeV cosmic rays

The 7 year data set of the Milagro TeV observatory contains 2.2 x 10(11) events of which most are due to hadronic cosmic rays. These data are searched for evidence of intermediate scale structure. Excess emission on angular scales of approximately 10 degrees has been found in two localized regions of unknown origin with greater than 12sigma significance. Both regions are inconsistent with pure gamma-ray emission with high confidence. One of the regions has a different energy spectrum than the isotropic cosmic-ray flux at a level of 4.6sigma, and it is consistent with hard spectrum protons with an exponential cutoff, with the most significant excess at approximately 10 TeV. Potential causes of these excesses are explored, but no compelling explanations are found.

Gastro-oesophageal reflux symptoms, oesophagitis and Barrett's oesophagus in the general population: the Loiano-Monghidoro study

OBJECTIVE

Existing endoscopy-based data on gastro-oesophageal reflux disease (GORD) in the general population are scarce. This study aimed to evaluate typical symptoms and complications of GORD, and their associated risk factors, in a representative sample of the Italian population.

METHODS

1533 adults from two Italian villages were approached to undergo symptom assessment using a validated questionnaire and upper gastrointestinal endoscopy. Data were obtained from 1033 individuals (67.4% response rate).

RESULTS

The prevalence of reflux symptoms was 44.3%; 23.7% of the population experienced such symptoms on at least 2 days per week (frequent symptoms). The prevalence rates of oesophagitis and Barrett's oesophagus in the population were 11.8% and 1.3%, respectively. Both frequent (relative risk (RR) 2.6; 95% confidence interval (CI) 1.7 to 3.9) and infrequent (RR 1.9; 95% CI 1.2 to 3.0) reflux symptoms were associated with the presence of oesophagitis. No reflux symptoms were reported by 32.8% of individuals with oesophagitis and 46.2% of those with Barrett's oesophagus. Hiatus hernia was associated with frequent reflux symptoms and oesophagitis, and was present in 76.9% of those with Barrett's oesophagus. We found no association between body mass index and reflux symptoms or oesophagitis.

CONCLUSIONS

GORD is common in Italy, but the prevalence of Barrett's oesophagus in the community is lower than has been reported in selected populations. Both frequent and infrequent reflux symptoms are associated with an increased risk of oesophagitis. Individuals with oesophagitis and Barrett's oesophagus often have no reflux symptoms.

Retinal and renal complications in patients with a mutation of mitochondrial DNA at position 3,243 (maternally inherited diabetes and deafness). A case-control study

AIMS/HYPOTHESIS

We assessed the prevalence and determinants of retinal and renal complications in patients with maternally inherited diabetes and deafness (MIDD).

METHODS

This was a multicentre prospective study comparing the prevalence of retinopathy and renal disease in 74 patients with MIDD and 134 control patients matched for sex, age and clinical presentation at onset of diabetes, duration of diabetes and current treatment. Comparisons were adjusted for HbA(1c) and hypertension.

RESULTS

In MIDD patients, HbA(1c) (7.6 +/- 1.6 vs 8.5 +/- 2.0%, p < 0.002), systolic blood pressure (126.6 +/- 16.2 vs 133.1 +/- 17.3 mmHg, p < 0.007) and prevalence of hypertension (33.8 vs 64.2%, p < 0.0001) were lower than in control patients. Prevalence of diabetic retinopathy was 3.7-fold lower in MIDD patients (6/74, 8 vs 40/134, 29.6%, p < 0.0001). Differences between groups remained significant after adjustment for hypertension, systolic blood pressure and HbA(1c). In MIDD, urinary albumin excretion (314.8 vs 80.1 mg/24 h, p = 0.035) and creatinine plasma levels (103.5 vs 82.2 micromol/l, p = 0.0178) were higher and GFR was lower. Impaired renal function (GFR <60 ml/min) was four- to sixfold more frequent in MIDD. Differences between MIDD and control diabetic patients further increased when adjusted for HbA(1c) and systolic blood pressure (p < 0.0001). Adjustment for treatment with an ACE inhibitor or angiotensin II receptor antagonist did not modify the results.

CONCLUSIONS/INTERPRETATION

This study indicates that diabetic retinopathy is less prevalent in MIDD than in control diabetes. This suggests that retinal alterations due to mitochondrial disease may have a protective role. By contrast, nephropathy is far more frequent in MIDD, suggesting the presence of a specific renal disease independent of diabetic nephropathy.

The epidemiology and virology of hepatitis C virus genotype 5 in central France

BACKGROUND

We previously reported high prevalence of hepatitis C virus genotype 5a (HCV 5) (14%) in Central France.

AIM

To identify the risk factors associated with HCV5 infection and to characterize local HCV5 lineages.

METHOD

A case-control study and phylogenetic analysis were conducted.

RESULTS

In all, 131 HCV5 and 343 HCV non 5 infected patients were enrolled. No HCV5 patient was born in sub-Saharan Africa and only two were injection drug user. HCV5 contamination was associated with living in a rural area called Vic le Comte (VLC) in non-transfused patients (OR = 17.7), with transfusion in patients living outside VLC (OR = 3.8) and with receiving injections in patients from VLC (OR = 3.1). More than 80% of the patients from outside VLC were contaminated by transfusion and those from VLC mainly by an iatrogenic factor - injections performed before 1972 by the local physician. Phylogenetic analysis of HCV5 isolates evidenced no distinct genetic cluster, but close relationships between the isolates of spouse pairs and between blood donors and recipients.

CONCLUSIONS

Our results suggest that HCV5 spread in our district by iatrogenic route before 1972 and then via transfusion to the whole district. Collaborative studies are underway to study viral sequences from different parts of Africa and Europe to estimate the origin of our HCV 5a strains.

A statistical model predicting high hepatocyte proliferation index and the risk of developing hepatocellular carcinoma in patients with hepatitis C virus-related cirrhosis

BACKGROUND

Incidence of hepatocellular carcinoma in hepatitis C virus-related cirrhosis is 4% per year. Although cost-effective, current screening could be improved.

AIM

To develop a statistical model including non-invasive parameters able to identify patients at high risk of developing hepatocellular carcinoma.

METHODS

One hundred and fifty-eight patients (73F:85M) with compensated chronic hepatitis C virus liver disease underwent evaluation, including argyrophilic nucleolar organizer regions proliferation index, and were followed up for 56.18 +/- 1.44 months.

RESULTS

Fifty-six patients had chronic hepatitis without cirrhosis and low argyrophilic nucleolar organizer regions proliferation index (< or =25%), 65 had hepatitis C virus-related cirrhosis and low argyrophilic nucleolar organizer regions proliferation index and 37 had hepatitis C virus-related cirrhosis and high argyrophilic nucleolar organizer regions proliferation index (>25%). Groups were similar for gender and viral genotype distribution. None of the patients with chronic hepatitis without cirrhosis developed hepatocellular carcinoma, compared with 6.1% of low argyrophilic nucleolar organizer regions proliferation index and 30.6% of high argyrophilic nucleolar organizer regions proliferation index (P = 0.002). By multivariable logistic regression analysis, the following parameters were independently associated with hepatocellular carcinoma development and used for the development of the statistical model: platelets (OR 0.98), gamma-globulins (OR 0.111), alanine aminotransferase/aspartate aminotransferase ratio (OR 0.07), serum ferritin (OR 1.0) and ultrasonographic pattern (coarse OR 2.9, coarse nodular OR 10.12). The statistical model properly allocated 95.9% of patients with low argyrophilic nucleolar organizer regions proliferation index and 72.2% of patients with high argyrophilic nucleolar organizer regions proliferation index.

CONCLUSIONS

The model, to be validated in large prospective studies, may help tailoring screening according to the risk of hepatocellular carcinoma development.

Inadequacy of the new Response Evaluation Criteria in Solid Tumors (RECIST) in patients with malignant pleural mesothelioma: report of four cases

Unidimensional Response Evaluation Criteria in Solid Tumor (RECIST) has been recently proposed in the attempt to simplify the standardized bidimensional World Health Organization (WHO) criteria. The complete accord between these two measurement systems was established in a large comparative study [J. Natl. Cancer Inst. 92(3) (2000) 205] that demonstrated the validity and the good performance of RECIST criteria. We report four cases of inadequacy of RECIST criteria in the evaluation of response to chemotherapy in patients with malignant pleural mesothelioma. These four patients were enrolled in two consecutive multicenter phase II clinical trials investigating the activity of a novel chemotherapy regimen in advanced pleural mesothelioma. They were judged as having an objective response to chemotherapy according to WHO criteria. Reassessed according to both methods, we found that results obtained with RECIST criteria do not correspond to WHO underestimating response to chemotherapy. Our data raise doubts about the applicability of unidimensional RECIST response criteria to mesothelioma and, possibly, to any tumor involving the chest wall.

Heterogeneity of diabetes phenotype in patients with 3243 bp mutation of mitochondrial DNA (Maternally Inherited Diabetes and Deafness or MIDD)

OBJECTIVE

In patients with maternally inherited diabetes and deafness (MIDD), due to 3 243 A > G mutation of mitochondrial DNA (mtDNA), diabetes may present with variable phenotypes.

OBJECTIVE

To ascertain the existence of two distinct phenotypes, MIDD1 and MIDD2, in a series of patients with MIDD.

DESIGN

Multicenter prospective study.

PATIENTS

77 patients with diabetes and the mtDNA 3243 mutation and 139 control patients with type 1 (T1D) or type 2 (T2D) diabetes, matched according to initial presentation of diabetes, age at onset, sex, and duration of diabetes (24 T1D and 115 T2D, including 55 treated with insulin).

MEASUREMENTS

Anthropometric characteristics (height, body weight, body mass index [BMI], sex), family history of diabetes, and characteristics of diabetes (age at onset, treatment, hemoglobin A1c [HbA1c]), extrapancreatic manifestations.

RESULTS

In 13 cases (17%, MIDD1), diabetes presented as insulin-dependent from the onset, with ketoacidosis in 6 cases. In 64 cases (83%, MIDD2), diabetes resembled T2D, and was treated with diet in 12 cases, oral hypoglycemic agents in 21 cases, or insulin in 31 cases. Compared with patients with MIDD2, patients with MIDD1 were characterized by lower age at onset of first manifestation of MIDD (25.4 +/- 9.6 vs 33.7 +/- 13.2 Years, P<0.0005), lower body weight (49.1 +/- 7.4 vs 56.3 +/- 10.9 kg, P<0.0025), lower BMI (18.2 +/- 2.3 vs 20.9 +/- 3.6 kg/m2, P<0.0005), and higher HbA1c levels (9.5 +/- 2.0 vs 7.5 +/- 1.6%, P<0.0005). Frequency of family history of diabetes and of extrapancreatic manifestations was the same in both MIDD subtypes. No difference was found within the MIDD2 subtype when comparing patients treated with or without insulin. Compared with matched controls, patients with MIDD had a lower BMI (MIDD1/T1D 18.2 +/- 2.3 vs 24.0 +/- 3.6 kg/m2 and MIDD2/T2D 20.9 +/- 3.6 vs 30.2 +/- 5.9 kg/m2, P<0.0025). Lastly, male patients with MIDD had a shorter height than controls (MIDD1/T1D: 166.1 +/- 3.2 vs 177.3 +/- 6.6 cm and MIDD2/T2D: 168.4 +/- 7.2 vs 173.6 +/- 6.6 cm P<0.025).

CONCLUSIONS

These results confirm the existence of two different phenotypes in MIDD, MIDD1 and MIDD2, which may be related to the severity of the mitochondrial disease. The role of other genetic and/or environmental factors in the variable phenotype of MIDD remains to be elucidated.

Evaluation of soluble CD44 in patients with breast and colorectal carcinomas and non-Hodgkin's lymphoma

CD44 is a transmembrane glycoprotein involved in cell-cell and cell-substrate interactions. As a cell surface molecule, CD44 may be shed or released into the circulation by proteolytic enzymatic mechanisms. Therefore, soluble CD44 can be found in cell culture supernatants as well as in plasma. In this study we evaluated the levels of soluble total CD44 (sCD44) in serum samples of patients with breast and colorectal carcinoma as well as non-Hodgkin's lymphoma in order to correlate prognosis with sCD44 expression. Besides, we evaluated other clinical tumour markers routinely used, Cancer Antigen (CA) 15.3 and CA 19.9. We investigated 132 serological samples from breast cancer patients, 48 sera from colorectal tumours, 48 samples from stage IV non-Hodgkin's lymphoma and sera from 80 individuals without evidence of cancer or autoimmune disease. Breast cancer patients were divided into three groups: a) patients with no clinical evidence of positive nodules and no metastatic disease; b) patients with positive nodules; and c) patients with metastasis. sCD44 mean serum levels in these groups were 198+/-54 ng/ml, 221+/-78 ng/ml and 242+/-119 ng/ml, respectively, while the marker CA 15.3 values were 15.6+/-6.6 U/ml, 14.0+/-5.8 U/ml and 211.5+/-358.9 U/ml, respectively. sCD44 levels for colorectal tumour were 243+/-72 ng/ml, while CA 19.9 serum levels were 230+/-270 U/ml. Stage IV non-Hodgkin's lymphoma sCD44 levels were 398+/-160 ng/ml. sCD44, CA 15.3 and CA 19.9 values for healthy individuals without evidence of any cancer pathology were 223+/-58 ng/ml, 16.4+/-6.2 U/ml and 33+/-14 U/ml, respectively. From these results we conclude that sCD44 might be used as a reliable marker for patients with non-Hodgkin's lymphoma. However, sCD44 levels failed to correlate with prognosis, tumour burden or metastasis in breast and colorectal cancer patients. Neither was any correlation found between high CA 15.3 or CA 19.9 levels and soluble CD44 serum level.

Clinical and prognostic value of serial renal biopsies in lupus nephritis

Little information is available about the role of repeated renal biopsies in lupus nephritis. We analyzed retrospectively the prognostic significance of serial renal biopsies in patients with lupus nephritis. Thirty-one patients with lupus nephritis underwent two or more renal biopsies during follow-up. The indications for repeated biopsy were as follows: improvement of renal disease but persistence of nonnephrotic proteinuria (group A, 7 patients); persistent or relapsing nephrotic syndrome (group B, 12 patients); and worsening of renal function (group C, 19 patients). After a median follow-up of 10.5 years, 17 patients reached the end point (persistent doubling of plasma creatinine level). At repeated renal biopsy, there was a correlation between improved clinical and histological features for group A. In these patients, treatment was reduced or stopped successfully. Histological features remained almost unchanged in group B. All patients showed an improvement of proteinuria after reinforcement of therapy. In group C, the worsening of renal function was associated with a variable and clinically unpredictable combination of active and chronic lesions. Only the few patients with an elevated activity index and moderate chronicity index showed a favorable and persistent improvement of renal disease after reinforcement of therapy. At multivariate analysis of clinical and histological data at presentation, only male sex was predictive of an adverse outcome (P = 0.015). At repeated renal biopsy, crescents in more than 30% of glomeruli (P = 0.0009) and chronicity index of 5 or greater (P = 0.00006) were associated with the probability of reaching the end point at multivariate analysis. Repeated renal biopsy may be helpful for establishing the prognosis in patients with lupus nephritis, particularly in the presence of worsening of renal function.

[Diabetic coronary disease and risk of myocardial infarction]

The raised incidence of myocardial infarction and sudden death in diabetics was explained over 20 years ago by the increase in prevalence and severity of coronary atherosclerosis. Coronary angiographies of 820 consecutive patients admitted to hospital for coronary artery disease were analysed. One hundred and fifteen of these patients (14%) were diabetic. In 77.4% of diabetics and 72.6% of non-diabetics, coronary angiography showed coronary lesions which were usually distal and three vessel in diabetics. When the three coronary arteries were analysed globally, the percentage of patients with at least one mild stenosis was much higher in diabetics than in non-diabetics (50.6% vs 30.3% respectively, p < 0.001), but there was no statistical difference in the number of severe stenoses or occlusions. The increase in mild stenosis in the diabetic population could indicate an anatomical predisposition to future rupture of a plaque. This result could explain the increased frequency of myocardial infarction and sudden death in diabetes, not necessarily preceded clinically by angina pectoris.

Prevalence of lymphocytic infiltrate in 1400 pituitary adenomas

To evaluate the prevalence of lymphocytic infiltrate in a large series of pituitary adenomas, we retrospectively studied tumor tissues from 1400 patients. Based on immunocytochemical data, tumors were classified as PRL (n=411), multihormonal (n=310), immunonegative (n=275), ACTH (n=166), GH (n=137), alpha subunit (n=44), FSH and/or LH, (n=42), and TSH (n=15) adenomas. The lymphocytic infiltrate was diagnosed on histological examination and investigated by immunostaining with anti LCA (human leucocyte common antigen), anti CD45RO (human T cell) and anti CD20 (human B cell) antibodies. Lymphocytic infiltrate was present in 40 adenomas (2.9%), 26 females and 14 males, aged 18 to 77 years (mean+/-SD, 37+/-14 years). The tumors were 19 PRL, 8 multihormonal, 4 GH, 4 alpha subunit, 3 ACTH, and 2 immunonegative adenomas. In PRL adenomas, the sex ratio (female/male) and the age were similar in patients with and without lymphocytic infiltrate (2.8 vs. 4.6 and 29+/-6 years vs. 32+/-11 years, respectively). The frequency of lymphocytic infiltrate was similar in PRL, GH, ACTH and multihormonal adenomas, but lymphocytic infiltrate was significantly more frequent in PRL adenoma than in immunonegative adenoma, and in alpha subunit adenoma than in immunonegative, ACTH and multihormonal adenomas. The lymphocytic cells were almost exclusively T cells. We conclude that lymphocytic infiltrates are rare in pituitary adenomas. Their frequency is not statistically different in major categories of secreting adenomas (PRL, GH, ACTH, multihormonal). Their pathophysiological significance remains to be established.

Increased incidence of moderate stenosis among patients with diabetes: substrate for myocardial infarction?

Persons with diabetes are at higher risk for myocardial infarction and sudden death than are persons without diabetes. It has been demonstrated that the artery that occludes during acute myocardial infarction generally had less than 75% stenosis on a previous angiogram. The extent of coronary artery stenosis was analyzed for 820 consecutively examined patients who underwent coronary angiography at our institution. The patients were categorized according to the presence or absence of diabetes mellitus. The severity of stenosis was taken into consideration. Patients with diabetes had moderate (50% to 75% narrowing) stenosis much more frequently than patients without diabetes (50.6 versus 30.3%, p < 0.001). Moreover diabetes mellitus was an independent risk factor for moderate stenosis. The lesions were more frequently located on distal arteries, more frequently had a pattern of three-vessel disease, and had a trend toward more diffuse disease than described 25 years ago. This greater amount of moderate stenosis may be considered a substrate for future acute plaque rupture. It may explain the high prevalence of acute myocardial infarction and sudden death among patients with diabetes without an increase in the incidence of angina pectoris.

Uptake and killing of Lyme disease and relapsing fever borreliae in the perfused rat liver and by isolated Kupffer cells

In situ-perfused rat livers were infused with a single dose of 1.5 x 10(7) radiolabeled borreliae. Significant (P < 0.00005) differences in the liver uptake of the agents of Lyme borreliosis, Borrelia burgdorferi IRS, Borrelia afzelii VS461, and Borrelia garinii PBi, and that of the agents of relapsing fever, Borrelia hermsii, Borrelia parkeri, and Borrelia turicatae, were observed. The liver uptakes ranged between 65.9% for B. burgdorferi IRS and 40.5% for B. turicatae. Neither relapsing fever nor Lyme disease borreliae were recovered from infected livers when the livers were cultured in Barbour-Stoenner-Kelly II medium. The in vitro uptake of B. burgdorferi IRS by isolated rat Kupffer cells was rapid, and within 30 min of the infection, large intracellular aggregates of amorphous material were detectable by immunofluorescence with specific anti-B. burgdorferi antibody. The reculturing of B. burgdorferi IRS from Kupffer cells incubated for 24 h in RPMI medium before inoculation with bacteria was negative. The results obtained in this study indicated that borreliae are efficiently taken up and killed by rat hepatic macrophages in the absence of serum factors.

[Nocturnal hypoglycemia in insulin-dependent diabetics]

OBJECTIVES

Repeated hypoglycaemia has been reported to impair recognition of subsequent hypoglycaemia with a high risk of severe hypoglycaemia. This intensified insulin therapy may be dangerous in insulin-dependent diabetes mellitus (IDDM) patients with unawareness of hypoglycaemia.

METHODS

We assessed the incidence of nocturnal hypoglycaemia and the benefit of an additional bedtime snack in IDDM patients treated by 2 or 3 daily injections. Capillary blood glucose was measured by finger strip at 10 p.m. and plasma venous glycaemia was determined at 0, 2, 4 and 8 a.m.

RESULTS

The study was composed of two phases. In the first phase, patients (n = 93) did not receive any snack at bedtime. Blood glucose fell to 2.75 mmol/l or less in 33%. Among the 40 patients with a 10 p.m. glycaemia of 9 mmol/l or less, 57.5% experienced nocturnal hypoglycaemia vs 15% of the 53 others. The second phase concerned 106 IDD patients. An additional bedtime snack was given when 10 p.m. blood glucose was 9 mmol/l or less. The incidence of hypoglycaemia fell to 32% (14 of 44 IDDM) i.e. a significant benefit of 44% (p < 0.01). However patients who received this additional bedtime snack had a slightly higher 8 a.m. glycaemia than those with 10 p.m. glycaemia at 9 mmol/l or less during the first phase (9.61 +/- 5.67 mmol/l vs 7.75 +/- 4.30 mmol/l) but this result is not significant.

CONCLUSION

Prevention of nocturnal hypoglycaemia may be achieved in IDDM patients by bedtime glucose determination and an additional snack when glycaemia is 9 mmol/l or less.

Pattern of glomerular involvement in human immunodeficiency virus-infected patients: an Italian study

Renal biopsy specimens from 26 adult human immunodeficiency virus (HIV)-infected patients with glomerular involvement were reviewed from the files of three hospital pathology services in Northern Italy. All the patients were Italian and most (19 of 26 patients) were intravenous drug addicts. The types of glomerular lesions were as follows: minimal-change glomerulopathy (two cases), mesangial proliferative glomerulonephritis (GN) with scanty immunoglobulin deposits (four cases), and various patterns of immune complex-mediated glomerulonephritis, including postinfectious GN (six cases), membranoproliferative GN (one case), membranous GN (three cases), immunoglobulin (Ig) A nephropathy (four cases), a mixed membranous and proliferative (three cases) and diffuse proliferative lupus-like pattern with subendothelial deposits, and intraluminal thrombi (two cases) or subepithelial and subendothelial deposits (one case). None of the patients had evidence of HIV-associated nephropathy. Our study confirms previous observations on the low incidence of HIV-associated nephropathy among white HIV-infected patients in Europe, where immune complex-mediated GN seems to predominate. Apart from the frequent electron microscopic observation of endothelial tubuloreticular structures, none of the reported lesions could be distinguished on morphologic grounds from those occurring in uninfected patients. The high variability of the glomerular lesions upholds the need for accurate diagnosis for the clinician confronted with an HIV-positive patient with suspected glomerular involvement.

[Endocrine diseases in POEMS syndrome. Apropos of 4 cases]

POEMS syndrome is a rare systemic multi-organ disease usually reported in Japanese patients. The clinical course is slow with a 5-year survival of 60%. Death is caused by polyneuropathy and or anasarka. We observed four cases in our ward (all males, aged 39, 57, 54 and 54 years) who all presented at least four characteristic clinical signs. Gynecomasty together with impotency was seen in all patients. All had hypogonadism and borderline hyperprolactinaemia. Hyperoestrogenism was seen in two. In three patients, rare endocrinopathies were part of the POEMS syndrome. One patient had diabetes mellitus. The clinical course was variable and a function of the effectiveness of plasmocyte dyscrasia therapy. Little work has been done on endocrinopathies in POEMS syndrome. In most cases, gonadotrope function is impaired with gynecomasty and impotency in men, amenorrhoea in women. Generally the hypogonadism is hypogonadotropic. Hyperoestrogenism is frequent and prolactin levels are normal or high with an exaggerated response to thyroid releasing hormone stimulation. The aetiology of POEMS syndrome is unknown. Current research is based on an immunologic theory based on the discovery of high levels of interleukin 6 in POEMS patients with or without Castleman's disease. The cytokine would affect the different organs and lead to clinical expression. Corticosteroids are usually effective in most patients, particularly in reducing the oedema and controlling the polyneuropathy.

Treatment of chronic sporadic-type non-A, non-B hepatitis with lymphoblastoid interferon: gamma GT levels predictive for response

The aim of this study was to evaluate the efficacy of human lymphoblastoid interferon-alpha treatment in chronic sporadic-type non-A, non-B hepatitis. We also aimed to determine if histological or liver function data could predict either response or relapse. Sixty patients with chronic sporadic-type non-A, non-B hepatitis were randomized in two groups of 30. One group was treated with interferon-alpha (3 MU thrice weekly) for one year; the other group was untreated controls. The treated group was followed for another year after interferon withdrawal. Liver function tests were performed during treatment. Liver biopsy was carried out before and a year after randomization. We evaluated rate of response [normalization of alanine aminotransferase (ALT) levels for at least three consecutive months] and rate of relapse (ALT rebound after therapy suspension). We also looked at possible predictive factors for response and relapse. In the treatment group the rate of response was 55% (16/29). No control patient exhibited ALT normalization. Among the responders, 31% (5/16) relapsed after interferon withdrawal. Low gamma GT and female sex are positive predictive factors of response (P < 0.01 and P < 0.02 respectively). Presence of portal and periportal inflammation at the second liver biopsy was correlated with relapse (P < 0.05). In conclusion, human lymphoblastoid interferon-alpha treatment for one year is beneficial in patients suffering from chronic sporadic-type non-A, non-B hepatitis. Low pretreatment gamma GT levels and female sex are positive predictors of response in this patient population.(ABSTRACT TRUNCATED AT 250 WORDS)