Inhibiting P. fluorescens biofilms with fluoropolymer-embedded silver nanoparticles: an in-situ spectroscopic study.

Surface colonization by microorganisms leads to the formation of biofilms, i.e. aggregates of bacteria embedded within a matrix of extracellular polymeric substance. This promotes adhesion to the surface and protects bacterial community, providing an antimicrobial-resistant environment. The inhibition of biofilm growth is a crucial issue for preventing bacterial infections. Inorganic nanoparticle/Teflon-like (CFx) composites deposited via ion beam sputtering demonstrated very efficient antimicrobial activity. In this study, we developed Ag-CFx thin films with tuneable metal loadings and exceptional in-plane morphological and chemical homogeneity. Ag-CFx antimicrobial activity was studied via mid-infrared attenuated total reflection spectroscopy utilizing specifically adapted multi-reflection waveguides. Biofilm was sampled by carefully depositing the Ag-CFx film on IR inactive regions of the waveguide. Real-time infrared spectroscopy was used to monitor Pseudomonas fluorescens biofilm growth inhibition induced by the bioactive silver ions released from the nanoantimicrobial coating. Few hours of Ag-CFx action were sufficient to affect significantly biofilm growth. These findings were corroborated by atomic force microscopy (AFM) studies on living bacteria exposed to the same nanoantimicrobial. Morphological analyses showed a severe bacterial stress, leading to membrane leakage/collapse or to extended cell lysis as a function of incubation time.

Complement C5a-Induced Changes in Neutrophil Morphology During Inflammation.

The complement and neutrophil defence systems, as major components of innate immunity, are activated during inflammation and infection. For neutrophil migration to the inflamed region, we hypothesized that the complement activation product C5a induces significant changes in cellular morphology before chemotaxis. Exposure of human neutrophils to C5a dose- and time-dependently resulted in a rapid C5a receptor-1 (C5aR1)-dependent shape change, indicated by enhanced flow cytometric forward-scatter area values. Similar changes were observed after incubation with zymosan-activated serum and in blood neutrophils during murine sepsis, but not in mice lacking the C5aR1. In human neutrophils, Amnis high-resolution digital imaging revealed a C5a-induced decrease in circularity and increase in the cellular length/width ratio. Biomechanically, microfluidic optical stretching experiments indicated significantly increased neutrophil deformability early after C5a stimulation. The C5a-induced shape changes were inhibited by pharmacological blockade of either the Cl-/HCO3--exchanger or the Cl- -channel. Furthermore, actin polymerization assays revealed that C5a exposure resulted in a significant polarization of the neutrophils. The functional polarization process triggered by ATP-P2X/Y-purinoceptor interaction was also involved in the C5a-induced shape changes, because pretreatment with suramin blocked not only the shape changes but also the subsequent C5a-dependent chemotactic activity. In conclusion, the data suggest that the anaphylatoxin C5a regulates basic neutrophil cell processes by increasing the membrane elasticity and cell size as a consequence of actin-cytoskeleton polymerization and reorganization, transforming the neutrophil into a migratory cell able to invade the inflammatory site and subsequently clear pathogens and molecular debris.

Parsonage-Turner syndrome due to autochthonous acute genotype 3f hepatitis E virus infection in a nonimmunocompromised 55-year-old patient.

Hepatitis E virus (HEV) infection is an emerging autochthonous disease in industrialized countries. Extra-hepatic manifestations, in particular neurologic manifestations, have been reported in HEV infection. Only a few cases of hepatitis E-associated Parsonage-Turner syndrome have been reported, and HEV genotypes were rarely determined. Here, we report the case of a Parsonage-Turner syndrome associated with an acute autochthonous HEV infection in a 55-year-old immunocompetent patient. HEV genomic RNA was detected in serum and cerebrospinal fluid samples (CSF), and molecular phylogenetic analysis of HEV was performed. The interest of this case lies in its detailed description notably the molecular analysis of HEV RNA isolated from serum and CSF. HEV infection should be considered in diagnostic investigations of neurologic manifestations associated with liver function perturbations.

Factors influencing the outcome (GOS) in reconstructive cranioplasty.

After performing a decompressive craniectomy, a cranioplastic surgery is usually warranted. The complications of this reconstructive procedure may differ from the initial operation. The authors of this study report on their experience to define patient-specific and procedural risk factors for possible complications following cranioplasty influencing the outcome (Glasgow Outcome Scale (GOS)), mobility, shunt dependency, and seizures. A retrospective analysis of 263 patients of all ages and both sexes who had undergone cranioplasty after craniectomy for traumatic brain injury (including chronic subdural hematoma), subarachnoidal hemorrhage (including intracerebral hemorrhage), ischemic stroke, and tumor surgery in one single center in 12 years from January 2000 to March 2012 has been carried out. A multiple logistic regression analysis was performed to identify potential risk factors (age, gender, used cranioplasty material, initial diagnosis, clipped or coil-embolized subarachnoidal hemorrhage (SAH) patients, time interval, complications especially hydrocephalus and seizures, mobility) upon the prognosis described as a dichotomized Glasgow Outcome Scale. Two hundred forty-eight patients met the study criteria. The overall complication rate after cranioplastic surgery was 18.5% (46 patients). Complications included: surgical site infection, epidural hematoma, hydrocephalus with or without former SAH, and new-onset seizures. Logistic regression analysis identified significant correlation between a low GOS (2 or 3) and postoperative seizures (OR 2.37, CI 1.35-4.18, p < 0.05), shunt-depending hydrocephalus (OR 5.83, CI 3.06-11.11, p < 0.05), and age between 51 and 70 years (OR 2.4, 95% CI 1.09-5.29, p = 0.029). However, gender, time interval between craniectomy and cranioplasty, initial diagnosis, and used cranioplasty material had no significant influence on post-cranioplasty complications as surgical site infections, hematoma, wound healing disturbance, seizures, or hydrocephalus. Evaluation of treatment modality in aneurysmal SAH clip vs. coil showed no significant relation to postoperative complications either. Complications after cranioplastic surgery are a common problem, as prognostic factors could identify a shunt-depending hydrocephalus and epilepsia to develop a major deficit after cranioplastic surgery (GOS 2 or 3). We detected a significant extra risk of people between the age of 51 and 70 years to end up in GOS level 2 or 3.

Toxicology: a discipline in need of academic anchoring--the point of view of the German Society of Toxicology.

The paper describes the importance of toxicology as a discipline, its past achievements, current scientific challenges, and future development. Toxicological expertise is instrumental in the reduction of human health risks arising from chemicals and drugs. Toxicological assessment is needed to evaluate evidence and arguments, whether or not there is a scientific base for concern. The immense success already achieved by toxicological work is exemplified by reduced pollution of air, soil, water, and safer working places. Predominantly predictive toxicological testing is derived from the findings to assess risks to humans and the environment. Assessment of the adversity of molecular effects (including epigenetic effects), the effects of mixtures, and integration of exposure and biokinetics into in vitro testing are emerging challenges for toxicology. Toxicology is a translational science with its base in fundamental science. Academic institutions play an essential part by providing scientific innovation and education of young scientists.

Cytotoxic and apoptotic effects of recombinant subtilase cytotoxin variants of shiga toxin-producing Escherichia coli.

In this study, the cytotoxicity of the recently described subtilase variant SubAB2-2 of Shiga toxin-producing Escherichia coli was determined and compared to the plasmid-encoded SubAB1 and the chromosome-encoded SubAB2-1 variant. The genes for the respective enzymatic active (A) subunits and binding (B) subunits of the subtilase toxins were amplified and cloned. The recombinant toxin subunits were expressed and purified. Their cytotoxicity on Vero cells was measured for the single A and B subunits, as well as for mixtures of both, to analyze whether hybrids with toxic activity can be identified. The results demonstrated that all three SubAB variants are toxic for Vero cells. However, the values for the 50% cytotoxic dose (CD50) differ for the individual variants. Highest cytotoxicity was shown for SubAB1. Moreover, hybrids of subunits from different subtilase toxins can be obtained which cause substantial cytotoxicity to Vero cells after mixing the A and B subunits prior to application to the cells, which is characteristic for binary toxins. Furthermore, higher concentrations of the enzymatic subunit SubA1 exhibited cytotoxic effects in the absence of the respective B1 subunit. A more detailed investigation in the human HeLa cell line revealed that SubA1 alone induced apoptosis, while the B1 subunit alone did not induce cell death.

Clinical relevance of herpes simplex virus viremia in Intensive Care Unit patients.

OBJECTIVES: To determine the clinical relevance of herpes simplex virus (HSV) viremia episodes in critically ill adult patients. METHODS: 1556 blood samples obtained for HSV PCR analysis in Intensive Care Unit (ICU) patients over 4 years were retrospectively analyzed, focusing on the comprehensive analysis of 88 HSV-viremic patients. RESULTS: HSV DNA was detected in 11.8% of samples from the ICU. HSV viral loads remained below 5×10(2) copies/ml in 68.2% of patients and exceeded 10(4) copies/ml in 7.9%. Episodes of HSV-viremia correlated with immunosuppressed status and mechanical ventilation in 79.5% and 65.9% of patients, respectively. Only a subset of patients exhibited HSV-related organ damage, including pneumonia and hepatitis (10.2% and 2.3%, respectively). The mortality rate in HSV-viremic patients was not significantly increased compared to the overall mortality rate in the ICU (27.3% vs. 22.9%, p = 0.33). Only patients with high HSV viral loads tended to have a higher, though non-significant, death rate (57.1%, p = 0.14). CONCLUSIONS: Our results suggest HSV viremia is common in ICU patients, potentially favored by immunocompromised status and mechanical ventilation. The global impact of HSV-viremia on mortality in the ICU was low. Quantifying HSV DNA may help identifying patients at-risk of severe HSV-induced symptoms.

High incidence but low burden of coronaviruses and preferential associations between respiratory viruses.

Respiratory viruses are the leading cause of acute infections in humans. However, the burden of certain respiratory viruses, such as coronaviruses, and the relevance of viral coinfections remain unclear. In this study, we investigated the distribution and seasonal occurrences of respiratory viruses detected by multiplex molecular assay in 6,014 samples from 2008 to 2011 in a French hospital. We assessed the detection frequencies of 14 respiratory viruses and their clinical impact in immunosuppressed and nonimmunosuppressed patients. Furthermore, we explored the preferential association patterns between respiratory viruses in multiple infections. Our results indicated that human rhinovirus/enterovirus (HRV/EV) and coronavirus (HCoV) were frequently detected in respiratory samples (48.81% and 11.74% of infected samples, respectively), and the detection frequencies of these viruses were further increased in immunosuppressed patients. The most common subtypes of HCoV were HCoV-229E (33.80%) and HCoV-HKU1 (32.39%). A sharp increase in the detection frequencies of HCoV-229E and HCoV-HKU1 over several months suggested that these subtypes were epidemic in our population. In immunosuppressed patients, HCoV contributed to upper respiratory tract infections (52%). Evidence did not support lower respiratory tract infections exclusive to a unique HCoV infection. In multiply infected individuals, determined in 6.3% of samples, HRV/EV and HCoV were detected in 33.29% and 22.90% of samples, respectively. Interestingly, nearly 50% of HCoV infections were detected in association with another virus. Since the distributions of respiratory viruses in multiply infected patients were subject to preferential association patterns between viruses, we propose complex interactions between different respiratory viruses and host factors.

Calcium stimulated calcitonin measurement: a procedural proposal.

Human calcitonin (hCT) is a tumor marker essential to the diagnosis and follow-up of medullary thyroid cancer (MTC). Current consensus recommends hCT measurement when initially evaluating thyroid nodules; if slightly elevated, a confirmatory stimulated calcitonin test is commonly performed, usually using pentagastrin. In recent years the supply of pentagastrin was not guaranteed with long periods of unavailability; the outlook for future availability is unknown. Therefore it is desirable for many institutions to establish a procedure for calcitonin stimulation using a stimulant with a secure supply; stimulation of calcitonin using calcium represents the easiest alternative.Several schemes and dosages have been used in the past for calcium stimulated calcitonin measurement. In this paper we propose a procedure for calcium stimulated calcitonin measurement based on our experiences. Furthermore we will briefly point out the limitations of this method with regard to available data in literature.

Mitochondrial DNA m.3242G > A mutation, an under diagnosed cause of hypertrophic cardiomyopathy and renal tubular dysfunction?

We present two new patients with the recently described mitochondrial m.3242G > A mutation. Although the mutation is situated next to the well known m.3243A > G mutation, the most common alteration associated with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome, the clinical presentation is quite different, but characteristic. All three m.3242G > A patients presented in the neonatal period with hypertrophic and dilated cardiomyopathy, generalized muscle hypotonia and lactic acidosis. Two additionally had creatine kinase elevation, renal tubular acidosis/dysfunction and showed a mild clinical course with a favourable psychomotor development. The third patient had more neurological involvement and died in infancy. The mutation occurred de novo in the two patients where maternal investigations were performed. The combination of hypertrophic cardiomyopathy and renal tubular acidosis/renal tubular dysfunction is clinically distinctive and may represent a separate entity.

Three dimensional rotational angiography in surgical planning of aneurysm clipping.

BACKGROUND: Three-dimensional (3D) angiography is increasingly used in the diagnostics of brain aneurysms. Aim of the present study was to evaluate the accuracy of 3D angiograms with respect to its value for preoperative planning of aneurysm clipping. PATIENTS AND METHODS: The 3D angiograms of 42 patients with subarachnoid bleeding caused by aneurysm rupture of the anterior circle of Willis and the intradural carotid have been compared to intraoperative photographs of the aneurysms. RESULTS: Neighbouring vessels, aneurysm anatomy, arteries originating from the aneurysm wall were accurately shown decreasing the surgical risk of aneurysm clipping. CONCLUSIONS: The 3D images enabled a perfect preoperative planning through the operation by illuminating the aneurysm anatomy, neck localisation and shape and relation of the aneurysm to neighbouring vessels. Operative approach, use of an accurate clip and avoidance of clipping arteries close to the aneurysm have become predictable and safer by the use of 3D angiography.

Effect of aging on the transverse toughness of human cortical bone: evaluation by R-curves.

The age-related deterioration in the quality (e.g., strength and fracture resistance) and quantity (e.g., bone-mineral density) of human bone, together with increased life expectancy, is responsible for increasing incidence of bone fracture in the elderly. The present study describes ex vivo fracture experiments to quantitatively assess the effect of aging on the fracture toughness properties of human cortical bone specifically in the transverse (breaking) orientation. Because bone exhibits rising crack-growth resistance with crack extension, the aging-related transverse toughness is evaluated in terms of resistance-curve (R-curve) behavior, measured for bone taken from a wide range of age groups (25-74 years). Using this approach, both the ex vivo crack-initiation and crack-growth toughness are determined and are found to deteriorate with age; however, the effect is far smaller than that reported for the longitudinal toughness of cortical bone. Whereas the longitudinal crack-growth toughness has been reported to be reduced by almost an order of magnitude for human cortical bone over this age range, the corresponding age-related decrease in transverse toughness is merely ~14%. Similar to that reported for X-ray irradiated bone, with aging cracks in the transverse direction are subjected to an increasing incidence of crack deflection, principally along the cement lines, but the deflections are smaller and result in a generally less tortuous crack path.

Resistant vasospasm in subarachnoid hemorrhage treated with continuous intraarterial nimodipine infusion.

Cerebral vasospasm complicating aneurysmal subarachnoid hemorrhage is a well-known medical entity. The delayed ischemic neurological deficits (DIND) as a result of vasospasm remain the main cause of morbidity among patients who manage to survive this severe disease pattern. When the traditional treatment options, either medical or interventional, fail to reverse vasospasm, continuous intraarterial infusion of nimodipine through catheters directly into the spastic arteries presents a promising treatment modality. Of 73 patients with aneurysmal subarachnoid hemorrhage between 2008 and 2009, a total of 27 had Hunt and Hess grades of 4 and 5. Fifteen percent of them showed refractory vasospasms and were treated with continuous nimodipine infusion via catheters in both internal carotid arteries. We present the method's indications and possible complications.

Transorbital impalement injury with massive intracranial lesion not detected by cranial CT scan.

An extraordinary case of transorbital penetration injury is presented. A 24-year-old male patient was involved in a fight and was pushed against a shelf. He immediately lost consciousness and was brought to hospital. A cranial computed tomogaphy (CT) scan showed a hemorrhage and brain edema over the left hemisphere with orbital roof fracture. A decompressive craniectomy was performed. Intraoperatively, an orbital roof fracture with penetration of the frontobasal dura could be seen which could not be explained by the trauma mechanism. The postoperative magnetic resonance imaging (MRI) with susceptibility-weighted image (SWI) showed two injury tracks from the orbit through the brain which appeared to be penetration injuries. The forensics department was consulted and penetration by a falling candleholder was found to be the cause of the injuries. In this case, the cranial CT alone did not show any indication of a penetration injury. Only MRI revealed the penetration track, which stresses the diagnostic value of this modality and especially the SWI in cases where the trauma mechanism does not correspond to the injury shown in the CT scan.

Outcome of craniocerebral gunshot injuries in the civilian population. Prognostic factors and treatment options.

AIM: Gunshot wounds to the head are rare in Europe. They may be inflicted by low-velocity handguns, captive bolt guns and tear gas cartridges and mostly result from suicide attempts. The experience of neurosurgeons with this kind of traumatic injury is decreasing; the aim of this study was therefore to analyse prognostic factors which help to decide whether or not to operate and to discuss treatment options. METHODS: Thirty patients with gunshot head injuries treated in our hospital from 1993 to 2008 were retrospectively evaluated. Glasgow Coma Scale (GCS) score, pupil reactivity, lesion localisation, number of bone fragments, intracranial pressure (ICP), midline shift, hypotension, and dural penetration were analysed for their prognostic value. Surgically and non-surgically treated patients were evaluated separately. Complications were registered. RESULTS: A low GCS of 3-8, fixed pupils, >2 bone fragments, bilobar or posterior fossa/brainstem lesions and ICP >45 mmHg were indicators of a poor prognosis. CONCLUSION: Patients with a GCS of 3-8 and two non-reactive pupils should not be operated. If one or both of the pupils are reactive, surgery should be performed irrespective of the GCS score, except in patients with translobar/transventricular wounds. Even if there are no clear contraindications to surgery, the outcome is expected to be poor in patients with a low GCS score, midline shift >10 mm, >2 bone fragments in the brain, and a bilobar, posterior fossa/brainstem or ventricular lesion and ICP >45 mmHg. When surgery is performed the wound and the missile or bone track should be debrided meticulously, the wound and dura should be closed in a watertight fashion and antibiotic prophylaxis as well as tetanus serum should be given.

Reduced size-independent mechanical properties of cortical bone in high-fat diet-induced obesity.

Overweight and obesity are rapidly expanding health problems in children and adolescents. Obesity is associated with greater bone mineral content that might be expected to protect against fracture, which has been observed in adults. Paradoxically, however, the incidence of bone fractures has been found to increase in overweight and obese children and adolescents. Prior studies have shown some reduced mechanical properties as a result of high-fat diet (HFD) but do not fully address size-independent measures of mechanical properties, which are important to understand material behavior. To clarify the effects of HFD on the mechanical properties and microstructure of bone, femora from C57BL/6 mice fed either a HFD or standard laboratory chow (Chow) were evaluated for structural changes and tested for bending strength, bending stiffness and fracture toughness. Here, we find that in young, obese, high-fat fed mice, all geometric parameters of the femoral bone, except length, are increased, but strength, bending stiffness, and fracture toughness are all reduced. This increased bone size and reduced size-independent mechanical properties suggests that obesity leads to a general reduction in bone quality despite an increase in bone quantity; yield and maximum loads, however, remained unchanged, suggesting compensatory mechanisms. We conclude that diet-induced obesity increases bone size and reduces size-independent mechanical properties of cortical bone in mice. This study indicates that bone quantity and bone quality play important compensatory roles in determining fracture risk.

Acute subdural hematoma in the elderly; clinical and CT factors influencing the surgical treatment decision.

OBJECTIVE: Acute subdural hematomas (aSDH) are severe traumatic brain injuries. Older patients have a higher mortality rate. In the present study the computed tomography (CT) and neurological deficits caused by aSDH were used as prognostic factors to define the outcome and surgical treatment indication in older patients. METHODS: The affect of the Glasgow Coma Scale (GCS) score on initial presentation, pupil abnormalities, parenchymal lesions, SDH-thickness, midline shift and intracranial pressure (ICP) in the outcome of older patients (>or=65 years old) admitted to our hospital between 1993 and 2006 with aSDH was evaluated. The outcome was assessed with the Glasgow Outcome Scale (GOS). The data were collected retrospectively. Statistical analysis was performed with Chi-square test and ANOVA. RESULTS: Older patients have a high mortality after aSDH. A low GCS score (3-8), pupil abnormalities, the presence of contusions and subarachnoid bleeding, midline shift>aSDH thickness as well as a highly elevated ICP>40 mmHg are unfavorable factors in the prognosis of aSDH. CONCLUSION: Patients with a GCS of 13-15 can be observed clinically (the expected outcome is very good). Comatose patients (GCS 3-8) with bilateral dilatation of the pupils should not be operated (very high mortality rate). If the GCS score is <13 and both pupils or only one are reactive to light and the midline shift<10 mm, surgery is indicated. If the midline shift is >10 mm and aSDH thickness>midline shift, surgery is also indicated. If in the same patient group midline shift>SDH thickness and ICP>40 mmHg, surgery is not indicated.

A subarachnoid haemorrhage primarily presenting as Terson's syndrome.

We present a case of a subarachnoid haemorrhage due to a ruptured basilar artery aneurysm in a 61-year-old woman. She presented with visual deterioration as the only clinical sign, no previous episodes of headache were reported. Fundoscopy showed a bilateral vitreous haemorrhage. A consecutively performed cranial computer tomography demonstrated subarachnoid bleeding. Further diagnostics revealed a basilar artery aneurysm that was successfully treated with coil embolisation. As a scarring of the vitreous bodies developed, they had to be removed. The patient's eyesight improved gradually and no further complications occurred.