Biological and protective properties of immune sera directed to the influenza virus neuraminidase

The envelope of influenza A viruses contains two large antigens, hemagglutinin (HA) and neuraminidase (NA). Conventional influenza virus vaccines induce neutralizing antibodies that are predominantly directed to the HA globular head, a domain that is subject to extensive antigenic drift. Antibodies directed to NA are induced at much lower levels, probably as a consequence of the immunodominance of the HA antigen. Although antibodies to NA may affect virus release by inhibiting the sialidase function of the glycoprotein, the antigen has been largely neglected in past vaccine design. In this study, we characterized the protective properties of monospecific immune sera that were generated by vaccination with recombinant RNA replicon particles encoding NA. These immune sera inhibited hemagglutination in an NA subtype-specific and HA subtype-independent manner and interfered with infection of MDCK cells. In addition, they inhibited the sialidase activities of various influenza viruses of the same and even different NA subtypes. With this, the anti-NA immune sera inhibited the spread of H5N1 highly pathogenic avian influenza virus and HA/NA-pseudotyped viruses in MDCK cells in a concentration-dependent manner. When chickens were immunized with NA recombinant replicon particles and subsequently infected with low-pathogenic avian influenza virus, inflammatory serum markers were significantly reduced and virus shedding was limited or eliminated. These findings suggest that NA antibodies can inhibit virus dissemination by interfering with both virus attachment and egress. Our results underline the potential of high-quality NA antibodies for controlling influenza virus replication and place emphasis on NA as a vaccine antigen. IMPORTANCE The neuraminidase of influenza A viruses is a sialidase that acts as a receptor-destroying enzyme facilitating the release of progeny virus from infected cells. Here, we demonstrate that monospecific anti-NA immune sera inhibited not only sialidase activity, but also influenza virus hemagglutination and infection of MDCK cells, suggesting that NA antibodies can interfere with virus attachment. Inhibition of both processes, virus release and virus binding, may explain why NA antibodies efficiently blocked virus dissemination in vitro and in vivo. Anti-NA immune sera showed broader reactivity than anti-HA sera in hemagglutination inhibition tests and demonstrated cross-subtype activity in sialidase inhibition tests. These remarkable features of NA antibodies highlight the importance of the NA antigen for the development of next-generation influenza virus vaccines.

Comparative dendritic cell biology of veterinary mammals.

Dendritic cells (DC) have a main function in innate immunity in that they sense infections and environmental antigens at the skin and mucosal surfaces and thereby critically influence decisions about immune activation or tolerance. As professional antigen-presenting cells, they are essential for induction of adaptive immune responses. Consequently, knowledge on this cell type is required to understand the immune systems of veterinary mammals, including cattle, sheep, pigs, dogs, cats, and horses. Recent ontogenic studies define bona fide DC as an independent lineage of hematopoietic cells originating from a common precursor. Distinct transcription factors control the development into the two subsets of classical DC and plasmacytoid DC. These DC subsets express a distinguishable transcriptome, which differs from that of monocyte-derived DC. Using a comparative approach based on phenotype and function, this review attempts to classify DC of veterinary mammals and to describe important knowledge gaps.

Death after Sexual Intercourse

Sexuality is an essential aspect of quality of life. Nevertheless, sexual intercourse is physically challenging and leads to distinct changes in blood pressure, heart, and respiratory rate that may lead to vital complications. We present a case report of a 22-year-old female suffering from subarachnoid hemorrhage after sexual intercourse. The patient was immediately transported to hospital by emergency medical services and, after diagnosis, transferred to a tertiary hospital with neurosurgical expertise but died within 24 hours. After postcoital headaches, subarachnoid hemorrhage is the second most common cause of neurological complications of sexual intercourse and therefore patients admitted to an emergency department with headache after sexual intercourse should always be carefully evaluated by cerebral imaging.

Risk Factors for Intracranial Haemorrhage in Accidents Associated with the Shower or Bathtub

BACKGROUND There has been little research on bathroom accidents. It is unknown whether the shower or bathtub are connected with special dangers in different age groups or whether there are specific risk factors for adverse outcomes. METHODS This cross-sectional analysis included all direct admissions to the Emergency Department at the Inselspital Bern, Switzerland from 1 January 2000 to 28 February 2014 after accidents associated with the bathtub or shower. Time, age, location, mechanism and diagnosis were assessed and special risk factors were examined. Patient groups with and without intracranial bleeding were compared with the Mann-Whitney U test.The association of risk factors with intracranial bleeding was investigated using univariate analysis with Fisher's exact test or logistic regression. The effects of different variables on cerebral bleeding were analysed by multivariate logistic regression. RESULTS Two hundred and eighty (280) patients with accidents associated with the bathtub or shower were included in our study. Two hundred and thirty-five (235) patients suffered direct trauma by hitting an object (83.9%) and traumatic brain injury (TBI) was detected in 28 patients (10%). Eight (8) of the 27 patients with mild traumatic brain injuries (GCS 13-15), (29.6%) exhibited intracranial haemorrhage. All patients with intracranial haemorrhage were older than 48 years and needed in-hospital treatment. Patients with intracranial haemorrhage were significantly older and had higher haemoglobin levels than the control group with TBI but without intracranial bleeding (p<0.05 for both).In univariate analysis, we found that intracranial haemorrhage in patients with TBI was associated with direct trauma in general and with age (both p<0.05), but not with the mechanism of the fall, its location (shower or bathtub) or the gender of the patient. Multivariate logistic regression analysis identified only age as a risk factor for cerebral bleeding (p<0.05; OR 1.09 (CI 1.01;1.171)). CONCLUSION In patients with ED admissions associated with the bathtub or shower direct trauma and age are risk factors for intracranial haemorrhage. Additional effort in prevention should be considered, especially in the elderly.

If hunters end up in the emergency room: a retrospective analysis of hunting injuries in a swiss emergency department.

Aim. to characterize the mechanisms, patterns, and outcomes of nonfatal hunting-related injuries in patients presenting to Bern University Hospital, Switzerland, and compare these to reports of hunting injuries worldwide. Methods. patients presenting with hunting-related injuries to the Emergency Department at Bern University hospital from 2000 to 2014 were identified by retrospectively searching the department database using the keyword "hunt." Each case was analyzed in terms of the patient age and gender, the mechanism and pattern of injury, and management and patient follow-up. Results. 19 patients were identified. 16 were male with a mean age of 50 years (range: 16-74). Mechanisms of injury included firearm-related injuries, falls, and knife wounds. The most common patterns of injury were head injuries (7), followed by injuries to the upper (5) or lower limb (5) and trunk (2). Over half of the patients were admitted, and nine required emergency surgery. Conclusion. Nonfatal hunting accidents in Bern, Switzerland, are largely caused by firearms and falls and tend to occur in male hunters with a mean age of 50 years. The most common patterns of injury are orthopedic and head injuries, often requiring surgery. These findings are consistent with international studies of nonfatal hunting accidents.

A below-ground herbivore shapes root defensive chemistry in natural plant populations

Plants display extensive intraspecific variation in secondary metabolites. However, the selective forces shaping this diversity remain often unknown, especially below ground. Using Taraxacum officinale and its major native insect root herbivore Melolontha melolontha, we tested whether below-ground herbivores drive intraspecific variation in root secondary metabolites. We found that high M. melolontha infestation levels over recent decades are associated with high concentrations of major root latex secondary metabolites across 21 central European T. officinale field populations. By cultivating offspring of these populations, we show that both heritable variation and phenotypic plasticity contribute to the observed differences. Furthermore, we demonstrate that the production of the sesquiterpene lactone taraxinic acid β-d-glucopyranosyl ester (TA-G) is costly in the absence, but beneficial in the presence of M. melolontha, resulting in divergent selection of TA-G. Our results highlight the role of soil-dwelling insects for the evolution of plant defences in nature.

Chronological clinical and pathological documentation of porcine ulcerative dermatitis

BACKGROUND: Porcine ulcerative dermatitis syndrome (PUDS) is a rare disease of breeding sows with an unknown pathogenesis. OBJECTIVE: To describe the evolution of clinical and histopathological lesions over the course of the disease and to elucidate the pathogenesis. ANIMAL: A 24-month-old, pluriparous, large white sow presented during gestation with ulcerations around the teats compatible with PUDS. METHODS AND RESULTS: Clinical and histopathological lesions were monitored over the course of the disease (i.e. during and after the subsequent pregnancy). A clear gestation-dependent flare of the lesions was observed with partial resolution occurring postpartum. The histological pattern presented as a lymphocytic interface dermatitis. CONCLUSIONS AND CLINICAL IMPORTANCE: The findings in this case report link gestation with the development of clinical signs and histological changes. Multiparity appears to enhance severity and may finally result in a self-perpetuating disease. Therefore, it seems advisable to cull breeding sows after they have developed PUDS.