A Photoactivated Protein Degrader for Optical Control of Synaptic Function.

Hundreds of proteins determine the function of synapses, and synapses define the neuronal circuits that subserve myriad brain, cognitive, and behavioral functions. It is thus necessary to precisely manipulate specific proteins at specific sub-cellular locations and times to elucidate the roles of particular proteins and synapses in brain function. We developed PHOtochemically TArgeting Chimeras (PHOTACs) as a strategy to optically degrade specific proteins with high spatial and temporal precision. PHOTACs are small molecules that, upon wavelength-selective illumination, catalyze ubiquitylation and degradation of target proteins through endogenous proteasomes. Here we describe the design and chemical properties of a PHOTAC that targets Ca 2+ /calmodulin-dependent protein kinase II alpha (CaMKIIα), which is abundant and crucial for baseline synaptic function of excitatory neurons. We validate the PHOTAC strategy, showing that the CaMKIIα-PHOTAC is effective in mouse brain tissue. Light activation of CaMKIIα-PHOTAC removed CaMKIIα from regions of the mouse hippocampus only within 25 µm of the illuminated brain surface. The optically-controlled degradation decreases synaptic function within minutes of light activation, measured by the light-initiated attenuation of evoked field excitatory postsynaptic potential (fEPSP) responses to physiological stimulation. The PHOTACs methodology should be broadly applicable to other key proteins implicated in synaptic function, especially for evaluating their precise roles in the maintenance of long-term potentiation and memory within subcellular dendritic domains.

Parvovirus B19-triggered hemophagocytic lymphohistiocytosis in a patient with Crohn's disease.

Background: Hemophagocytic lymphohistiocytosis (HLH) is a life threatening condition caused by inappropriate immune activity. Infection is often the trigger, both in genetically predisposed and in sporadic cases. Although more commonly seen in the paediatric population, patients of all ages can be affected. Case presentation: A 26-year-old male patient with Crohn's disease, treated with ustekinumab, presented with high fever, epistaxis and anorexia. Laboratory results showed pancytopenia, and a high serum levels of ferritin and LDH. Colonoscopy revealed only mild signs of disease activity. CT-scan showed splenomegaly and multiple lymphadenopathies. Bone marrow aspirate was suggestive for hemophagocytosis. PCR & serology for parvovirus B19 came back positive. Treatment with ustekinumab was temporarily put on hold and supportive care was given. Viral replication decreased and he recovered completely. Conclusion: There is a known association between HLH and Crohn's disease. This is probably because they are more susceptible to infections with CMV, EBV and parvovirus B19, all known as triggers for HLH. The role of ustekinumab is unclear: did it play a role in the pathophysiological evolution of this primo-infection with parvovirus B19? On the other hand, did it contribute to the rather mild course of the disease, acting as a immunomodulator that works on interleukin-12, a cytokine that plays a role in HLH? Further study is warranted to answer these questions.

Tigecycline-induced inhibition of mitochondrial DNA translation may cause lethal mitochondrial dysfunction in humans.

BACKGROUND: A 65-year-old patient developed an unexplained and ultimately lethal metabolic acidosis under prolonged treatment with tigecycline. Tigecycline is known to have a selective inhibitory effect on eukaryotic mitochondrial translation. The underlying molecular mechanisms of the metabolic acidosis in this patient were explored. METHODS: Oxidative phosphorylation system (OXPHOS) analysis, blue native polyacrylamide gel electrophoresis followed by in-gel activity staining in mitochondria, molecular analysis of mitochondrial DNA (mtDNA) for genomic rearrangements and sequencing of the rRNA genes was performed on the subject's skeletal muscle. RESULTS: OXPHOS analysis revealed a combined deficiency of the complexes I, III, IV and V, with a preserved function of complex II (encoded by nuclear DNA), thus demonstrating a defective mtDNA translation. There were no known underlying mitochondrial genetic defects. The patient had a (m.1391T>A) variant within the 12SrRNA gene in heteroplasmy (50-60%). CONCLUSIONS: This patient developed an ultimately lethal mitochondrial toxicity while receiving prolonged treatment with tigecycline, which was caused by a defective translation of the mtDNA. Tigecycline is known to suppress eukaryotic mitochondrial DNA translation, but until now this effect has been considered to be clinically insignificant. The observations in this patient suggest a clinically significant mitochondrial toxicity of tigecycline in this patient, and warrant further investigation.

Diagnostic thresholds for free light chains in multiple myeloma depend on the assay used.

Leukemia accepted article preview online, 20 November 2017. doi:10.1038/leu.2017.335.

Prolonged course of hepatic granulomatous disease due to Bartonella henselae infection.

Cat-scratch disease (CSD) is an emerging zoonosis caused by Bartonella henselae. The disease is usually self-limiting and typically presents in about 90% of all cases as a subacute regional lymphadenopathy. We present a case report of an unusual CSD presentation, persistent hepatic granulomatous disease due to Bartonella henselae infection despite combination therapy with doxycycline and rifampicin. Furthermore, a review of literature was conducted. (Acta gastroenterol. belg., 2016, 79, 497-499).

Outbreak of leptospirosis during a scout camp in the Luxembourg Belgian province, Belgium, summer 2012.

An outbreak of leptospirosis occurred in the South of Belgium, during August 2012, in teenagers who participated in two consecutive adventure scout camps near the Semois river. Among the symptomatic patient population (ten scouts), clinical manifestations included headache (70%), myalgia (50%), fever (50%), bilateral conjunctival injection (50%), general malaise (30%), vomiting (20%), anorexia (20%) and cough (20%). Some of the cases presented elevated blood creatinine (40%), or proteinuria (30%). Three patients were confirmed by serology and one by polymerase chain reaction. Potential risk factors included direct contact with a muskrat and indirect contact with potentially contaminated environments including the river water. Prospective environmental investigation carried out near the river banks 2 weeks after the outbreak identified Ondatra zibethicus (muskrat) as one Leptospira sp. reservoir.

Let's not forget herpes simplex virus in case of fulminant hepatic failure.

Fulminant herpes simplex virus (HSV) hepatitis is a rare condition, which is usually identified only after orthotopic liver transplantation (OLT) or at autopsy. The most commonly affected individuals are immunosuppressed patients, although HSV hepatitis can occur in immunocompetent patients as well. A high degree of suspicion combined with early diagnostic modalities may improve survival. We present a case report of fulminant herpetic hepatitis, requiring OLT. In addition, a review of the literature was performed.

Bordetella pertussis seroprevalence in Belgian adults aged 20-39 years, 2012.

SUMMARY The last report on pertussis seroprevalence in Belgium concerned samples collected during 1993-1994. In the context of the Eupert-Labnet WP6 seroprevalence study (comparing sera from 16 European member states), 1500 anonymized leftover diagnostic samples were collected randomly during the second semester of 2012 by the clinical chemistry laboratories of six participating Belgian centres, distributed equally between Flanders, Wallonia and Brussels Capital Region. As suggested by the WP6 organizers, a total of 750 samples (125/centre) were selected from subjects in the 20-29 years age group and 750 samples (125/centre) from subjects in the 30-39 years age group. Anti-PT IgG levels were measured using Virion-Serion ELISA and analysed using predefined cut-off levels. Sixty-one (4%) sera were indicative of an infection in the past 2 years (between 50 and 100 IU/ml) and another 61 (4%) sera had anti-PT IgG antibodies reflecting acute infection (>100 IU/ml). These results highlight the presence of a Bordetella pertussis reservoir in the adult 'healthy' Belgian population.

Low yield by molecular detection of Chlamydophila pneumoniae in respiratory samples in Belgium questioning its etiological role in respiratory tract infections.

The actual burden of respiratory infections due to Chlamydophila pneumoniae is difficult to assess due to the major differences in positivity rates between PCR- and serology-based methods. The aim of the current study was to objectively analyse the yield of PCRs for the detection of C. pneumoniae in respiratory samples and to evaluate the additional value of performing laboratory diagnosis for C. pneumoniae in a setting of respiratory infection. The data based on routine analysis of respiratory samples with request for C. pneumoniae detection were collected from 4 large Belgian hospitals during 2 consecutive years. In total 3560 respiratory samples have been analysed and overall only 7 samples (0.2%) were found positive. Based on these observations, the critical evaluation of the actual role of C. pneumoniae in the etiology of lower respiratory infections and consequently of the extensive use of diagnostic tools for the detection of C. pneumoniae is needed.

Prospective evaluation of Coris Influ-A&B Respi-Strip and of BinaxNOW Influenza A&B assay against viral culture and real-time PCR assay for detection of 2009 pandemic influenza A/H1N1v in Belgian patients.

PURPOSE: Evaluation of the performance of two rapid (15') antigen detection tests (RAT), BinaxNOW Influenza A&B and Coris Influ-A&B Respi-Strip for the detection of A(H1N1)v2009. STUDY DESIGN: Between July 2009 and November 2009, 4105 respiratory specimens from patients with influenza-like illness attending seven public hospitals in Brussels were prospectively examined by two immunochromatographic RAT, followed by viral culture and/or specific real-time RT-PCR. RESULTS: Samples consisted predominantly of nasopharyngeal aspirates (NPA-41%), nasopharyngeal (NPS-37%) and throat swabs (TS-14%). The sensitivity and specificity of Coris RAT and BinaxNOW RAT were 36.6% and 99.7%, and 47% and 98.7% respectively compared to culture; and 33.7% and 99.6%; and 46.5% and 98.8% compared to RT-PCR. Significant differences in sensitivity could be observed when splitting up the samples by sample type and patient's age. NPA gave by far the highest sensitivities: 51.1- 62% for Coris compared to culture and 62.6-78.4% for BinaxNOW. Sensitivities in paediatric NPS varied less between different hospitals (34-41.9%) being still much higher than in adult NPS (11.4-20%). TS resulted in unsatisfactory results: 13% sensitivity in children and 10.5% in adults. CONCLUSIONS: Both RAT showed excellent specificities, but insufficient sensitivities. Consequently, negative results should be confirmed. NPA are clearly superior to NPS orTS, and they stay the sample of choice for viral diagnosis.

Viral aetiology of influenza-like illness in Belgium during the influenza A(H1N1)2009 pandemic.

The purpose of this investigation was to determine the proportion of influenza-like illness (ILI) attributable to specific viruses during the influenza A(H1N1)2009 pandemic and to describe the demographic and clinical characteristics of ILI due to respiratory viruses in Belgium. Nasopharyngeal swabs were collected from ILI patients by general practitioners (GPs) and paediatricians (PediSurv) and analysed for viruses. Of 139 samples collected from children <5 years of age by PediSurv, 86 were positive, including 28 influenza (20%), 27 respiratory syncytial virus (RSV) (19%), 21 rhinovirus (17%), 12 human metapneumovirus (hMPV) (9%) and ten parainfluenza virus (PIV) (7%). Of 810 samples received from GPs, 426 were influenza (53%). Of 312 influenza-negative samples, 41 were rhinovirus (13%), 13 RSV (4%), 11 PIV (4%) and three hMPV (1%). Influenza mostly affected the 6-15 years old age group. Other respiratory viruses were commonly detected in the youngest patients. Similar clinical symptoms were associated with different respiratory viruses. Influenza A(H1N1)2009 was the most detected virus in ILI patients during the 2009-2010 winter, suggesting a good correlation between ILI case definition and influenza diagnosis. However, in children under 5 years of age, other respiratory viruses such as RSV were frequently diagnosed. Furthermore, our findings do not suggest that the early occurrence of the influenza A(H1N1)2009 epidemic impacted the RSV epidemic in Belgium.

Hospital preparedness and clinical description of the 2009 influenza A (H1N1) pandemic in a Belgian tertiary hospital.

We describe hospital preparedness, including costs, and clinical characteristics of the 2009 influenza A (H1N1) pandemic in adult patients in a Belgian tertiary care centre. A task force coordinated the overall management, including triage and hospitalisation. Between 1 June and 30 November 2009, 521 patients with influenza-like illness were admitted to the emergency ward. We reviewed data from 43 hospitalised patients with confirmed influenza A. Median age was 44 years (range: 21-79), with 84% patients having underlying disease. Eleven needed admission to intensive care unit (ICU) and one patient died. The financial impact of the epidemic was estimated at €75,691, and approximately half of these costs were related to the enhanced infection control practices. The Belgian 2009 influenza A (H1N1) pandemic, as described in a cohort of 43 hospitalised patients, was associated with a relatively high ICU admission rate of 26% and a fairly typical mortality rate of 3%. This retrospective study may help us refine the management of future epidemics.

[Fever after a stay in the tropics]. / Fièvre au retour des Tropiques.

We report the case of a patient suffering from dengue fever after returning from Guadeloupe. The differential diagnosis of fever after a stay in the tropics is discussed and attention is drawn on the emergence and diagnosis pitfalls of dengue fever.

Topical treatment of CIN 2+ by cidofovir: results of a phase II, double-blind, prospective, placebo-controlled study.

OBJECTIVE: Randomized controlled trial evaluating a topical treatment for cervical intraepithelial neoplasia 2 and 3 (CIN 2+) using cidofovir. METHODS: Fifty-three women with a biopsy-proven CIN 2+ were randomly assigned, 6 weeks before their planned conisation, either 3 applications of 3 ml 2% cidofovir in Intrasite gel in a cervical cap or a placebo (the same volume of Intrasite alone). A cervical sample for high-risk types of human papillomaviruses (HPV) (Hybrid Capture 2 or HC2) was taken before treatment and before conisation. The cone was submitted for pathological examination, and subsequently, along with the initial biopsy, to in situ hybridization (ISH) for high-risk HPV. RESULTS: Forty-eight patients were treated and followed according to the protocol, (23 cidofovir, and 25 placebo). Fourteen of the 23 cones were free of any CIN (60.8%) in the cidofovir group. Only 5 of 25 cones were free of any CIN (20%) in the placebo group (p<0.01). The difference remained significant in the ITT group (p<0.05). In the per-protocol and ITT populations, we observed more frequent viral clearance in the cidofovir group, but the difference was significant only when evaluated by ISH and not by HC2. No systemic toxicity was observed. Cervico-vaginal side effects of cidofovir were limited, and not statistically different from placebo. CONCLUSION: The medical topical treatment with cidofovir, at this point, cannot replace conisation, but it is a promising candidate for topical chemotherapy of CIN 2+ lesions; a larger prospective randomized study is needed to confirm our results.

Mathematical model for the control of nosocomial norovirus.

A gastroenteritis outbreak in a long-term care facility was analysed by means of a SEIR (Susceptible, Exposed/Latent phase, Infected/Infectious, and Recovered) compartment model of infection dynamics in a closed population [96 beds; attack rate=41%; R0 (basic reproductive number)=3.74; generation time approximately 1 day; duration of disease approximately 2 days; theoretical infinite (1000 days) duration of hospital stay]. The patient-turnover variation was simulated to determine the effect of the length of hospital stay on the endemic level of gastroenteritis perpetuating the epidemic phase in an open population. With all the other parameters held constant, the prevalence of infected patients in the endemic phase (50 days after the beginning of the outbreak) increased markedly from five to 18 cases as the hospital stay increased from one-tenth of a day (one-day care) to one or two days; the prevalence decreased exponentially with the length of hospital stay, being fewer than five cases for hospital stays >50 days. In conclusion, the endemic prevalence of norovirus gastroenteritis is critically dependent on the patient turnover within hospital wards. For the usual range of hospital stay (0.1-20 days), the prevalence level is sufficiently elevated to maintain the perpetuation of gastroenteritis within the population of institutionalised patients. In long-term care facilities (hospital stay >20 days), the patient turnover is sufficiently low for one to expect a spontaneous extinction of epidemic outbreak without endemic perpetuation. When an epidemic outbreak occurs in an acute-care setting, reinforcement of infection control measures, including closure of the ward, is required to break the transmission chain.

Exercise capacity in chronic fatigue syndrome.

BACKGROUND: Patients with chronic fatigue syndrome (CFS) suffer from various symptoms, including debilitating fatigue, muscle pain, and muscle weakness. Patients with CFS can experience marked functional impairment. In this study, we evaluated the exercise capacity in a large cohort of female patients with CFS. METHODS: Patients with CFS and matched sedentary control subjects performed a maximal test with graded increase on a bicycle ergometer. Gas exchange ratio was continuously measured. In a second stage, we examined only those persons who achieved a maximal effort as defined by 2 end points: a respiratory quotient of at least 1.0 and an age-predicted target heart rate of at least 85%. Data were assessed using univariate and multivariate statistical methods. RESULTS: The resting heart rate of the patient group was higher, but the maximal heart rate at exhaustion was lower, relative to the control subjects. The maximal workload and maximal oxygen uptake attained by the patients with CFS were almost half those achieved by the control subjects. Analyzing only those persons who performed a maximal exercise test, similar findings were observed. CONCLUSIONS: When compared with healthy sedentary women, female patients with CFS show a significantly decreased exercise capacity. This could affect their physical abilities to a moderate or severe extent. Reaching the age-predicted target heart rate seemed to be a limiting factor of the patients with CFS in achieving maximal effort, which could be due to autonomic disturbances. Arch Intern Med. 2000;160:3270-3277.

Long-term stability of human immunodeficiency virus viral load and infectivity in whole blood.

BACKGROUND: We intended to evaluate the stability of human immunodeficiency virus (HIV) type 1 virions in whole blood and in culture medium. MATERIALS AND METHOD: EDTA whole-blood samples taken from 12 patients were left at room temperature for up to 7 days, and aliquots of a laboratory virus stock spiked in EDTA, in heparinized or in citrated whole blood, with or without the addition of Triton X-100, or spiked in culture medium were left at room temperature for up to 120 days before plasma was separated and frozen at -80 degrees C. Viral load was measured for all frozen plasma samples using different viral load assays. p24 antigen and infectivity were also measured in the spiked samples. RESULTS: The patient whole-blood samples did not show any decrease in viral load during this 7-day period. The spiked samples decayed by not more than 1 log after 120 days (about 4 months), with the fastest decay in medium. Virus infectivity decayed very slowly from 20,000 units mL-1 to undetectable amounts after 56 days. CONCLUSIONS: These results indicate that HIV-1 virions in whole blood possess a long-term stability in terms of viral load, p24 antigen level and infectivity, which is not sufficiently recognized by laboratory and health care workers.

Failure to quantify viral load with two of the three commercial methods in a pregnant woman harboring an HIV type 1 subtype G strain.

The level of HIV-1 RNA in plasma has become one of the most important markers in the follow-up of HIV-infected patients. Three techniques are commercially available: both the Amplicor HIV Monitor and the NASBA HIV-1 RNA QT are target amplification methods, whereas the Quantiplex HIV RNA assay is a branched DNA signal amplification technique. Detection in both target amplification techniques is based on a single primer pair and a single probe in the gag region, whereas multiple probes capture the pol region of the viral RNA in the branched DNA assay. We investigated the discrepant observation of an undetectable viral load in an immunodeficient pregnant HIV-1-infected patient of African origin with no prior antiretroviral treatment. Although clinical progression was present in this patient with tuberculosis and a low CD4 cell count, viral load determinations with both the Amplicor Monitor and NASBA assays revealed no detectable RNA levels. The presence of HIV-1 RNA in the plasma of the patient was demonstrated by an in-house RNA-PCR. Subsequent HIV-1 RNA quantification with the branched DNA method revealed a high viremia (460,000 copies/ml). DNA sequence analysis of the gag gene identified a subtype G HIV-1 strain (HIV-1BL). To our knowledge this is the first report of a patient harboring an HIV-1 genotype of the main group with a high viral load as quantified by the branched DNA assay, but undetectable with the two commercial HIV RNA amplification techniques because of genetic divergence. In the case of discrepant low viral loads determined by one amplification technique in patients with advanced clinical stage one should use an alternative quantification technique for confirmation.

Comparative evaluation of three ELISA techniques and an indirect immunofluorescence assay for the serological diagnosis of Epstein-Barr virus infection.

BACKGROUND: The reference method for detecting specific Epstein-Barr virus (EBV) antibodies is indirect immunofluorescence (IF) with EBV-infected cells. The availability of protein purified from infected cells and more recently of recombinant polypeptides designed to contain immunodominant epitopes, has enabled the development of commercial enzyme-linked immunosorbent assays (ELISA) for the specific serodiagnosis of EBV infection. OBJECTIVE: Evaluation of ELISA-based EBV serodiagnosis in comparison with indirect immunofluorescence. STUDY DESIGN: We have first compared three commercial ELISA test systems with our in house indirect immunofluorescence assay for classifying correctly a set of serum samples into clinical categories (acute infection, past infection, interfering non-EBV infection, persistent infection). Additionally a prospective analysis with the best performing ELISA test (Enzygnost) was then carried out by running the ELISA test in parallel with the indirect immunofluorescence assay on 324 consecutive clinical samples sent to our laboratory for EBV serodiagnosis. RESULTS: For the serodiagnosis of past EBV infection and acute EBV infection all three commercial ELISAs performed well in comparison with indirect immunofluorescence. When testing samples positive for cytomegalovirus (CMV), Toxoplasma or herpes simplex IgM, interference in the IgM tests was observed with the three ELISAs. In some instances we could demonstrate that the positive IgM results were due to EBV reactivation. The observed discrepancies between ELISA and IF for the serodiagnosis of chronic EBV infection or EBV reactivation, point to the difficulty for the serodiagnosis of persistent EBV infection on single serum samples. According to our prospective study the EBV IgG determination was accurate. A positive IgM result was not always indicative of an acute infection. Positive IgM results due to EBV reactivation were observed. A positive EBV nuclear antigen (EBNA) IgG result in those samples precluded acute infection. CONCLUSIONS: 90-95% of samples could be classified correctly into clinical categories by a two parameter ELISA system detecting IgG and IgM against a standardized mixture of EBV antigens, allowing standardization and automation of EBV-specific serology. The absence of EBNA IgG was useful as a second line confirmatory assay for acute EBV infection.