Longitudinal changes in global structural brain connectivity and cognitive performance in former hospitalized COVID-19 survivors: an exploratory study.

BACKGROUND: Long-term sequelae of COVID-19 can result in reduced functionality of the central nervous system and substandard quality of life. Gaining insight into the recovery trajectory of admitted COVID-19 patients on their cognitive performance and global structural brain connectivity may allow a better understanding of the diseases' relevance. OBJECTIVES: To assess whole-brain structural connectivity in former non-intensive-care unit (ICU)- and ICU-admitted COVID-19 survivors over 2 months following hospital discharge and correlate structural connectivity measures to cognitive performance. METHODS: Participants underwent Magnetic Resonance Imaging brain scans and a cognitive test battery after hospital discharge to evaluate structural connectivity and cognitive performance. Multilevel models were constructed for each graph measure and cognitive test, assessing the groups' influence, time since discharge, and interactions. Linear regression models estimated whether the graph measurements affected cognitive measures and whether they differed between ICU and non-ICU patients. RESULTS: Six former ICU and six non-ICU patients completed the study. Across the various graph measures, the characteristic path length decreased over time (ß = 0.97, p = 0.006). We detected no group-level effects (ß = 1.07, p = 0.442) nor interaction effects (ß = 1.02, p = 0.220). Cognitive performance improved for both non-ICU and ICU COVID-19 survivors on four out of seven cognitive tests 2 months later (p < 0.05). CONCLUSION: Adverse effects of COVID-19 on brain functioning and structure abate over time. These results should be supported by future research including larger sample sizes, matched control groups of healthy non-infected individuals, and more extended follow-up periods.

[HIV-associated haematological complications]. / Pathologies hématologiques liées à l'infection par le VIH.

Despite recent advances in combined anti- retroviral therapy that have profoundly changed the prognosis of HIV infection, HIV-associated haematological complications remains frequent whatever the stage of the disease. Some types of lymphoma observed a dramatic reduction in their incidences but others such as diffuse B-cell lymphoma and Hodkin lymphoma remain as frequent as before the CART era. Treatments for lymphoma are nowadays not different for people living with HIV than for others. Other non- neoplastic diseases such as immune thrombo- penic purpura, thrombotic microangiopathies and hemophagocytic lymphohistiocytosis are still associated with HIV infection and will be discussed.

Bien que les traitements antirétroviraux combinés aient profondément modifié le pronostic de l'infection par le VIH, les complications hématolo- giques associées au VIH restent fréquentes à tous les stades de la maladie. Certains types de lymphomes ont vu leur incidence fortement diminuer alors que d'autres (lymphome B diffus et lymphome de Hodgkin) ont gardé une incidence stable. Le traitement de ces lymphomes n'est plus censé différer entre les personnes vivant avec le VIH et les autres. Les pathologies non malignes telles que les purpuras thrombo- péniques immuns, les microangiopathies thrombotiques et les syndromes d'activation macrophagiques, également associées au VIH, seront également abordées.

Difficult to treat osteoarticulars infections : Focus on Mycobacterial and Fungal infection.

Bone and joint infections are rare but often devastating. While bacteria are most commonly encountered organisms, mycobacteria and fungi are less frequent. Management of the latter is often more complex, especially in the presence of foreign material. We will increasingly be faced with mycobacterial and fungal bone infections, as medical conditions and newer therapeutics lead to more immunosuppression. In this article, we will review osteomyelitis, septic arthritis and peri-prosthetic joint infections related to mycobacteria and fungi.

Genotypic resistance determined by whole genome sequencing versus phenotypic resistance in 234 Escherichia coli isolates.

Whole genome sequencing (WGS) enables detailed characterization of bacteria at single nucleotide resolution. It provides data about acquired resistance genes and mutations leading to resistance. Although WGS is becoming an essential tool to predict resistance patterns accurately, comparing genotype to phenotype with WGS is still in its infancy. Additional data and validation are needed. In this retrospective study, we analysed 234 E. coli isolates from positive blood cultures using WGS as well as microdilution for 11 clinically relevant antibiotics, to compare the two techniques. We performed whole genome sequencing analyses on 234 blood culture isolates (genotype) to detect acquired antibiotic resistance. Minimal inhibitory concentrations (MIC) for E. coli were performed for amoxicillin, cefepime, cefotaxime, ceftazidime, meropenem, amoxicillin/clavulanic acid, piperacillin/tazobactam, amikacin, gentamicin, tobramycin, and ciprofloxacin, using the ISO 20776-1 standard broth microdilution method as recommended by EUCAST (phenotype). We then compared the two methods for statistical 'agreement'. A perfect (100%) categorical agreement between genotype and phenotype was observed for gentamicin and meropenem. However, no resistance to meropenem was observed. A high categorical agreement (> 95%) was observed for amoxicillin, cefepime, cefotaxime, ceftazidime, amikacin, and tobramycin. A categorical agreement lower than 95% was observed for amoxicillin/clavulanic acid, piperacillin/tazobactam, and ciprofloxacin. Most discrepancies occurred in isolates with MICs within ± 1 doubling dilution of the breakpoint and 22.73% of the major errors were samples that tested phenotypically susceptible at higher antibiotic exposure and were therefore considered as 'not resistant'. This study shows that WGS can be used as a valuable tool to predict phenotypic resistance against most of the clinically relevant antibiotics used for the treatment of E. coli bloodstream infections.

Antibiotic prescriptions in the context of suspected bacterial respiratory tract superinfections in the COVID-19 era: a retrospective quantitative analysis of antibiotic consumption and identification of antibiotic prescription drivers.

This study aims to quantify antibiotic consumption for suspected respiratory tract superinfections in COVID-19 patients, while investigating the associated drivers of antibiotic prescribing in light of the current signs of antibiotic overuse. Adult patients with a positive COVID-19 diagnosis admitted to a Belgian 721-bed university hospital were analyzed retrospectively (March 11th-May 4th, 2020), excluding short-term admissions (< 24 h). Antibiotic prescriptions were analyzed and quantified, using Defined Daily Doses (DDD) per admission and per 100 bed days. Possible drivers of antibiotic prescribing were identified by means of mixed effects logistic modelling analysis with backwards selection. Of all included admissions (n = 429), 39% (n = 171) were prescribed antibiotics for (presumed) respiratory tract superinfection (3.6 DDD/admission; 31.5 DDD/100 bed days). Consumption of beta-lactamase inhibitor-penicillin combinations was the highest (2.55 DDD/admission; 23.3 DDD/100 bed days). Four drivers were identified: fever on admission (OR 2.97; 95% CI 1.42-6.22), lower SpO2/FiO2 ratio on admission (OR 0.96; 95% CI 0.92-0.99), underlying pulmonary disease (OR 3.04; 95% CI 1.12-8.27) and longer hospital stay (OR 1.09; 95% CI 1.03-1.16). We present detailed quantitative antibiotic data for presumed respiratory tract superinfections in hospitalized COVID-19 patients. In addition to knowledge on antibiotic consumption, we hope antimicrobial stewardship programs will be able to use the drivers identified in this study to optimize their interventions in COVID-19 wards.

A Sphingosine-1-Phosphate Receptor Modulator Attenuated Secondary Brain Injury and Improved Neurological Functions of Mice after ICH.

BACKGROUND: Stroke activates the immune system and induces brain infiltration by immune cells, aggravating brain injury. Poststroke immunomodulation via (S1P-)receptor modulation is beneficial; however, the S1P-modulator in clinical use (FTY-720) is unspecific, and undesirable side effects have been reported. Previously, we tested effects of a novel selective S1P-receptor modulator, Siponimod, on ICH-induced brain injury in acute stage of the disease. In the current study, we investigated whether protective effects of Siponimod, evaluated in a short-term study, will protect the brain of ICH animals at long term as well. METHODS: 134 C57BL/6N mice were divided into sham and ICH-operated groups. Collagenase model of ICH was employed. ICH animals were divided into Siponimod treated and nontreated. Dose- and time-dependent effects of Siponimod were investigated. Contraplay between development of brain injury and the number of lymphocytes infiltrating the brain was investigated by forelimb placing, T-Maze test, brain water content calculation, MRI scanning, and immunostaining. RESULTS: Depending on the therapeutic strategy, Siponimod attenuated the development of brain edema, decreased ICH-induced ventriculomegaly and improved neurological functions of animals after ICH. It was associated with less lymphocytes in the brain of ICH animals. CONCLUSION: Siponimod is able to decrease the brain injury and improves neurological functions of animals after ICH.

Serelaxin activates eNOS, suppresses inflammation, attenuates developmental delay and improves cognitive functions of neonatal rats after germinal matrix hemorrhage.

Germinal matrix hemorrhage (GMH) is a detrimental form of neonatal CNS injury. Following GMH-mediated eNOS inhibition, inflammation arises, contributing to GMH-induced brain injury. We investigated the beneficial effects of Serelaxin, a clinical tested recombinant Relaxin-2 protein, on brain injury after GMH in rats. We investigated whether effects of Serelaxin are mediated by its ability to activate the GMH-suppressed eNOS pathway resulting in attenuation of inflammatory marker overproduction. GMH was induced by intraparenchymal injection of bacterial collagenase (0.3U). Seven day old Sprague-Dawley rat pups (P7) were used (n = 63). GMH animals were divided in vehicle or serelaxin treated (3 µg once, 30 µg once, 30 µg multiple, i.p., starting 30 after GMH and then daily). Sham operated animals were used. We monitored the developmental profile working memory and spatial function (T-maze and open field test respectively). At day 28, all rats underwent MRI-scans for assessment of changes in cortical thickness and white matter loss. Effects of Serelaxin on eNOS pathway activation and post-GMH inflammation were evaluated. We demonstrated that Serelaxin dose-dependently attenuated GMH-induced developmental delay, protected brain and improved cognitive functions of rats after GMH. That was associated with the decreased post-GMH inflammation, mediated at least partly by amelioration of GMH-induced eNOS inhibition.

Safety and cost savings of an improved three-day rule for stool culture in hospitalised children and adults.

Stools sent for culture from patients after three days of hospitalisation have a low yield (<1%) for bacterial enteric pathogens (BEP), excluding Clostridium difficile, and are expensive to process. A 'three-day rule' for rejection of specimens has previously been validated in adults. We evaluated a three-day rule for paediatric stool samples by retrospective review of all stool culture results from 1995 to 2002. Excluding C. difficile, yield for BEP in samples sent within three days following admission was 97/3751 (2.59%) compared with 3/1511 (0.2%) in samples sent more than three days after admission. The criteria for culture would have been met if the rule had been applied for these three samples. We prospectively evaluated potential savings if the rule were applied for both children and adults over a two-month period in 2000. Savings were greater for adults than for children. Of 490 stools from children, 38 (7.8%) samples did not meet the criteria for culture and of 206 stools from adult patients, 64 (31%) did not meet the criteria for culture. We implemented the rule between 1 March 2003 and 31 March 2006. A total of 14 439 stool samples were received from inpatients requesting culture for BEP, excluding C. difficile. Of these, 5744 (39.8%) were rejected because the criteria for culture were not met. This was estimated as an annual saving of 11,848 pounds to the Trust laboratory. If extrapolated to all NHS Trusts, the potential savings could be in the order of 1.18 million pounds annually.

Disappearance of biologic activity of synthetic LRH in normal and hypogonadal men.

The disappearance rates of the biologic activity of synthetic LRH have been measured in normal and hypogonadal men before and during estrogen treatment. Biologic activity was assayed by the change in radioimmunoassayable rat LH levels induced by injection of human plasma into ovariectomized rats pretreated with estrogen and progesterone, and compared with a dose-response curve using synthetic LRH. Following rapid iv injection of 100 micrograms synthetic LRH, peripheral blood peak levels of biologic activity occurred in less than 2-6 minutes, and the disappearance curve contained 2 exponential components. In 3 normal men the initial component had a t1/2 of 2 minutes and the second component a t1/2 of 10 minutes. Six hypogonadal men had first and second components of disappearance no different from normals whether or not they responded to LRH injection with increased endogenous hLH. While diethylstilbestrol 2 mg orally for 7 days suppressed pituitary hLH response to exogenous synthetic LRH (mean max.deltahLH 236 VS 46 NG/ml), it did not alter the disappearance rates in normal or hypogonadal men. These studies show that the biologic activity of synthetic LRH disappears from the blood after iv administration at rates similar to radioimmunoassayable and radioactive-labeled LRH. They further suggest that the lack of pituitary responsiveness to LRH in hypogonadal and estrogen-treated men is not due to more rapid clearance of the releasing hormone.

Abnormal gonadotropin secretory responses to LRH in transsexual women after diethylstilbestrol priming.

To determine whether female transsexuals have abnormal hypothalamic-pituitary feedback control, pituitary LH and FSH secretory responses to synthetic LRH (100 micrograms iv) were measured in nine female transsexuals with normal menstrual cycles before and after a 7-day course of treatment with diethylstilbestrol (DES; 2 mg/day). Control groups included five heterosexual women and seven heterosexual men. Pituitary responses to LHR in heterosexual women studied in the early follicular phase increased markedly after DES administration and were clearly different from responses in men, which were all inhibited by DES. Responses to LRH in nine transsexual women studied in the early follicular phase differed strikingly from normal women in that gonadotropin responses were not enhanced by DES. The finding that the responses of female transsexuals to DES and LRH were intermediate between the female and the male patterns suggests that a biological abnormality accompanies the psychological abnormality in such patients.

Pulsatile subcutaneous nocturnal administration of GnRH by portable infusion pump in hypogonadotropic hypogonadism: initiation of gonadotropin responsiveness.

GnRH was administered subcutaneously in hourly pulses for 10 consecutive nights to two immature males with Kallmann's Syndrome using a portable, battery-operated infusion pump adapted for home use. Pulsatile GnRH produced a progressive increase in urinary gonadotropin excretion, a significant increase in mean basal plasma FSH, pulsatile LH release, and an increased LH response to a standard 3 hour GnRH infusion test. One subject developed a striking increment in plasma testosterone in response to GnRH pulses, as well as a biphasic LH response to the 3 hour infusion.

Neuroendocrine reactivity to nicotine in smokers.

The present study explored neuropeptide responses to nicotine from smoking. Habitual smokers smoked research cigarettes of known strength under controlled laboratory conditions while blood samples were withdrawn unobtrusively for subsequent biochemical analysis. To provide a metric that reflected total nicotine intake and total neurohormonal output, data were integrated over time. Subjects were relatively unresponsive in the low-nicotine (0.48 mg) condition. In the high-nicotine (2.87 mg) condition, there were significant positive correlations between integrated plasma nicotine and plasma arginine vasopressin (r = +0.985), its carrier protein neurophysin I (r = +0.944), and beta-endorphin-beta-lipotropin (r = +0.977), but not adrenocorticotropic hormone. Data from an experiment that used an extraction step to remove beta-lipotropin corroborated the functional relationship between plasma nicotine and beta-endorphin implied by the original findings. Taking into account recent research on the role of neuropeptides in the modulation of affective states and cognitive function as well as of other CNS activity, the present findings were interpreted as strengthening the hypothesis that nicotine-stimulated neuropeptide release provides positive reinforcement for smoking.

The effects of smoking on ACTH and cortisol secretion.

The relationship among changes in plasma nicotine, ACTH, and cortisol secretion after smoking were investigated. Ten male subjects smoked cigarettes containing 2.87 mg nicotine and 0.48 mg nicotine. No rises in cortisol or ACTH were detected after smoking 0.48 mg nicotine cigarettes. Cortisol rises were significant in 11 of 15 instances after smoking 2.87 mg nicotine cigarettes, but ACTH rose significantly in only 5 of the 11 instances where cortisol increased. Each ACTH rise occurred in a subject who reported nausea and was observed to be pale, sweaty, and tachycardic. Peak plasma nicotine concentrations were not significantly different in sessions when cortisol rose with or without ACTH increases, but cortisol increases were significantly greater in nauseated than in non-nauseated smokers. Our data suggest that smoking-induced nausea stimulates cortisol release by stimulating ACTH secretion and that cortisol secretion in non-nauseated smokers may occur through a non-ACTH mechanism. It is not clear whether nicotine or some other stimulus inherent in smoking is responsible for cortisol secretion without ACTH secretion.

Pituitary hormone response to cigarette smoking.

Nausea was induced by having subjects smoke two high nicotine cigarettes in quick succession. Plasma levels of prolactin, adrenocorticotropic hormone, beta-endorphin/beta-lipotropin, growth hormone, arginine vasopressin, and neurophysin I increased without changes in thyroid stimulating hormone, luteinizing hormone, or follicle stimulating hormone. Nausea and pituitary hormone release correlated with high nicotine intake (smoking 2.87 mg nicotine cigarettes) but did not occur during lower nicotine intake (smoking 0.48 mg nicotine cigarettes). Individual differences in nausea and related hormonal responses may provide an objective method for predicting receptivity to smoking.

Isolation and characterization of an utero-active compound from Agave americana.

Crude extracts of Agave americana contain two utero-active compounds. One of these, tentatively named "Fraction B", has been purified to chromatographic homogeneity. Its pharmacological actions are similar to those of acetylcholine. However its chromatographic and electrophoretic mobilities are different. Some chemical properties of fraction B are compatible with the structure of an acyl derivative of choline different from acetylcholine.

Diffusion-weighted imaging in rectal carcinoma patients without and after chemoradiotherapy: a comparative study with histology.

Diffusion-weighted imaging (DWI) can be used to quantitatively assess functional parameters in rectal carcinoma that are relevant for prognosis and treatment response assessment. However, there is no consensus on the histopathological background underlying the findings derived from DWI. The aim of this study was to perform a comparison of DWI and histologic parameters in two groups of rectal carcinoma patients without (n=12) and after (n=9) neoadjuvant chemoradiotherapy (CRT). The intravoxel incoherent motion (IVIM) model was used to calculate the diffusion coefficient D and the perfusion fraction f in rectal carcinoma, the adjacent rectum and fat in the two patient groups. Immunohistological analysis was performed to assess the cellularity, vascular area fraction and vessel diameter for comparison and correlation. Out of 36 correlations between parameters from DWI and histology, four were found to be significant. In rectal carcinoma of patients without CRT, the diffusion D and the perfusion f correlated with the vascular area fraction, respectively, which could not be found in the group of patients who received CRT. Further correlations were found for the rectum and fat. Histological evaluation revealed significant differences between the tissues on the microscopic level concerning the cellular and vascular environment that influence diffusion and perfusion. In conclusion, DWI produces valuable biomarkers for diffusion and perfusion in rectal carcinoma and adjacent tissues that are highly dependent of the underlying cellular microenvironment influenced by structural and functional changes as well as the administered treatment, and consequently can be beyond histological ascertainability.

Community associated methicillin-resistant Staphylococcus aureus.

Community associated methicillin resistant Staphylococcus aureus (CA-MRSA) is an emergent infectious pathogen that might become an important public-health problem. Indeed, unique strains of S. aureus that combine specific virulence factors with resistance against frequently used antibiotics have been associated with severe community acquired infections in otherwise healthy and often younger people. This is especially the case in the USA, were these strains now represent a major part of staphylococcal infections in the outpatient setting. But, severe infections with CA-MRSA strains have already been reported in Belgium as well. This article summarizes the current knowledge on CA-MRSA as an emergent pathogen and discusses its clinical management.