In-Depth Characterization of Layer 5 Output Neurons of the Primary Somatosensory Cortex Innervating the Mouse Dorsal Spinal Cord

Neuronal circuits of the spinal dorsal horn integrate sensory information from the periphery with inhibitory and facilitating input from higher central nervous system areas. Most previous work focused on projections descending from the hindbrain. Less is known about inputs descending from the cerebral cortex. Here, we identified cholecystokinin (CCK) positive layer 5 pyramidal neurons of the primary somatosensory cortex (CCK ⁺ S1-corticospinal tract [CST] neurons) as a major source of input to the spinal dorsal horn. We combined intersectional genetics and virus-mediated gene transfer to characterize CCK⁺ S1-CST neurons and to define their presynaptic input and postsynaptic target neurons. We found that S1-CST neurons constitute a heterogeneous population that can be subdivided into distinct molecular subgroups. Rabies-based retrograde tracing revealed monosynaptic input from layer 2/3 pyramidal neurons, from parvalbumin positive cortical interneurons, and from thalamic relay neurons in the ventral posterolateral nucleus. Wheat germ agglutinin-based anterograde tracing identified postsynaptic target neurons in dorsal horn laminae III and IV. About 60% of these neurons were inhibitory and about 60% of all spinal target neurons expressed the transcription factor c-Maf. The heterogeneous nature of both S1-CST neurons and their spinal targets suggest complex roles in the fine-tuning of sensory processing.

Exercise training increases skeletal muscle mitochondrial volume density by enlargement of existing mitochondria and not de novo biogenesis

AIMS

(i) To determine whether exercise-induced increases in muscle mitochondrial volume density (Mito_VD ) are related to enlargement of existing mitochondria or de novo biogenesis and (ii) to establish whether measures of mitochondrial-specific enzymatic activities are valid biomarkers for exercise-induced increases in Mito_VD .

METHOD

Skeletal muscle samples were collected from 21 healthy males prior to and following 6 weeks of endurance training. Transmission electron microscopy was used for the estimation of mitochondrial densities and profiles. Biochemical assays, western blotting and high-resolution respirometry were applied to detect changes in specific mitochondrial functions.

RESULT

Mito_VD increased with 55 ± 9% (P < 0.001), whereas the number of mitochondrial profiles per area of skeletal muscle remained unchanged following training. Citrate synthase activity (CS) increased (44 ± 12%, P < 0.001); however, there were no functional changes in oxidative phosphorylation capacity (OXPHOS, CI+II_P ) or cytochrome c oxidase (COX) activity. Correlations were found between Mito_VD and CS (P = 0.01; r = 0.58), OXPHOS, CI+CIIP (P = 0.01; R = 0.58) and COX (P = 0.02; R = 0.52) before training; after training, a correlation was found between Mito_VD and CS activity only (P = 0.04; R = 0.49). Intrinsic respiratory capacities decreased (P < 0.05) with training when respiration was normalized to Mito_VD. This was not the case when normalized to CS activity although the percentage change was comparable_. CONCLUSIONS: Mito_VD was increased by inducing mitochondrial enlargement rather than de novo biogenesis. CS activity may be appropriate to track training-induced changes in Mito_VD.

Evidence for enzootic circulation of Rift Valley fever virus among livestock in Cameroon

Rift Valley fever virus (RVFV) is an arthropod-borne pathogen, causing serious epidemics in Africa and the Arabian Peninsula. In Cameroon serological data indicate the presence of RVFV, but active circulation of RVFV, causing clinical infections has not been proven yet. For this purpose we carried out a serological and molecular study on a total of 1953 randomly selected serum samples of small ruminants and cattle, which were collected in years 2013 and 2014 in Cameroon. In a first step, sera were screened serologically using a variety of assay formats to reveal RVFV specific antibodies. At the second stage, seropositive specimen were assessed for acute RVFV infections via IgM-specific ELISA and quantitative real-time RT-PCR. Our data show a significant difference in the antibody prevalence in cattle (13.5% [95% confidence interval: 11.4-15.7]) and small ruminants (3.4% [95% confidence interval: 2.3-4.7]), with indications for annual fluctuations and significant regional differences of seropositivity. One small ruminant and three bovines were eventually found to be positive in IgM ELISA and indications for viremia were found in one bovine by RVFV genome detection using quantitative real-time RT-PCR. The results of this study therefore corroborate the presence of acute RVFV-infection and its circulation in Cameroon.

Rift Valley fever virus infections in Egyptian cattle and their prevention

Rift Valley fever virus (RVFV) causes consistently severe outbreaks with high public health impacts and economic losses in livestock in many African countries and has also been introduced to Saudi Arabia and Yemen. Egypt with its four large outbreaks in the last 40 years represents the northernmost endemic area of RVFV. The purpose of this study was to provide an insight into the current anti-RVFV antibody status in immunized as well as non-immunized dairy cattle from the Nile Delta of Egypt. During 2013-2015, a total of 4,167 dairy cattle from four governorates including Dakahlia, Damietta, Gharbia and Port Said were investigated. All cattle were born after 2007 and therewith after the last reported Egyptian RVFV outbreak in 2003. The samples derived from vaccinated animals from 26 different dairy farms as well as non-immunized cattle from 27 different smallholding flocks. All samples were examined following a three-part analysis including a commercially available competition ELISA, an in-house immunofluorescence assay and a virus neutralization test. Additionally, a subset of samples was analysed for acute infections using IgM ELISA and real-time reverse transcriptase PCR. The results indicated that the RVFV is still circulating in Egypt as about 10% of the non-immunized animals exhibited RVFV-specific antibodies. Surprisingly, the antibody prevalence in immunized animals was not significantly higher than that in non-vaccinated animals which points out the need for further evaluation of the vaccination programme. Due to the substantial role of livestock in the amplification and transmission of RVFV, further recurrent monitoring of the antibody prevalence in susceptible species is highly warranted.

Indigenous West Nile virus infections in horses in Albania

Serum samples collected from 167 equines of 12 districts in Albania were tested for West Nile virus-specific antibodies by enzyme-linked immunosorbent assay and virus neutralization assay, using WNV lineage 1 and 2. In addition, 95 bird serum samples from Albania and 29 horse samples from Kosovo were tested in ELISA. An overall seroprevalence rate of 22% was found in horses from Albania, whereas no specific antibodies were found in the equine samples from Kosovo and the bird samples. This is the first report indicating WNV infections in animals in Albania, and the first reported seroprevalence study conducted for Kosovo. These results provide evidence for widespread infections of WNV in Albania.

Integrin inhibition promotes atypical anoikis in glioma cells

Integrins regulate cellular adhesion and transmit signals important for cell survival, proliferation and motility. They are expressed by glioma cells and may contribute to their malignant phenotype. Integrin inhibition may therefore represent a promising therapeutic strategy. GL-261 and SMA-560 glioma cells grown under standard conditions uniformly detached and formed large cell clusters after integrin gene silencing or pharmacological inhibition using EMD-121974, a synthetic Arg-Gly-Asp-motif peptide, or GLPG0187, a nonpeptidic integrin inhibitor. After 120 h, the clusters induced by integrin inhibition decayed and cells died. In contrast, when cells were cultured under stem cell (sphere) conditions, no disaggregation became apparent upon integrin inhibition, and cell death was not observed. As poly-HEMA-mediated detachment had similar effects on cell viability as integrin inhibition, we postulated that cell death may result from detachment alone, which was confirmed using various permissive and nonpermissive substrates. No surrogate markers of apoptosis were detected and electron microscopy confirmed that necrosis represents the dominant morphology of detachment-induced cell death. In addition, integrin inhibition resulted in the induction of autophagy that represents a survival signal. When integrins were inhibited in nonsphere glioma cells, the TGF-β pathway was strongly impaired, whereas no such effect was observed in glioma cells cultured under sphere conditions. Cell death induced by integrin inhibition was rescued by the addition of recombinant transforming growth factor-β (TGF-β) and accelerated by exposure to the TGF-β receptor inhibitor, SD-208. In summary, cell death following integrin inhibition is detachment mediated, represents an atypical form of anoikis involving necrosis as well as autophagy, and is modulated by TGF-β pathway activity.

Monitoring of West Nile virus infections in Germany

West Nile virus (WNV) is a flavivirus that is maintained in an enzootic cycle between ornithophilic mosquitoes, mainly of the Culex genus, and certain wild bird species. Other bird species like ravens, jays and raptors are highly susceptible to the infection and may develop deadly encephalitis, while further species of birds are only going through subclinical infection. The objective of this study was to continue in years 2009-2011 the serological and molecular surveillance in wild birds in Germany (see Vector Borne Zoonotic Dis. 10, 639) and to expand these investigations for the first time also to sera from domestic poultry and horses collected between 2005 and 2009. All three cohorts function as indicators for the endemic circulation of WNV. The presence of WNV-specific antibodies was detected in all samples by virus neutralization test (VNT), indirect immunofluorescence test (IFT) and/or enzyme-linked immunosorbent assay (ELISA). The presence of WNV genomes was monitored in relevant sera using two qRT-PCRs that amplify lineage 1 and 2 strains. A total of 364 migratory and resident wild bird serum samples (with emphasis on Passeriformes and Falconiformes) as well as 1119 serum samples from domestic poultry and 1282 sera from horses were analysed. With the exception of one hooded crow, antibody carriers were exclusively found in migratory birds, but not in resident birds/domestic poultry or in local horses. Crows are facultative, short-distance winter migrants in Germany. WNV-specific nucleic acids could not be demonstrated in any of the samples. According to these data, there is no convincing evidence for indigenous WNV infections in equines and in wild/domestic birds in Germany. However, since a few years, WNV infections are endemic in other European countries such as Austria, Hungary, Greece and Italy, a state-of-the-art surveillance system for the detection of incursions of WNV into Germany deems mandatory.

Experimental challenge of cattle with German atypical bovine spongiform encephalopathy (BSE) isolates

For almost two decades after the discovery of the first bovine spongiform encephalopathy (BSE) case, it was generally accepted that only one BSE strain existed globally. However, in 2004, two novel BSE forms (L-type and H-type) were separately identified in two different European Member States, forms that differed from the classical (C-type) form by their biochemical properties and by the pattern of PrP(Sc) deposition as determined by immunohistochemistry (IHC). 60 atypical BSE cases have been identified worldwide as of November 2010, including one H- and one L-type BSE case each in Germany. However, it was not known whether the biological properties (pathogenesis and agent distribution, as well as transmissibility to other species) of these novel forms were the same as in classical BSE cases. Eleven calves were thus challenged intracranially, five with the German H-type and six with German L-type BSE cases. The experimental design and the clinical studies, followed by laboratory testing, are described in this manuscript.

Characterization of a 320-kb region containing the HEXA gene on bovine chromosome 10 and analysis of its association with BSE susceptibility

Bovine spongiform encephalopathy (BSE) belongs to a group of neurodegenerative diseases known as transmissible prion diseases. Recently, variants in the promoter region of the prion protein (PRNP) gene have been shown to have a considerable effect on the susceptibility to BSE. However, a previous genome scan revealed other putative BSE-susceptibility loci. Here, we analysed such a region on BTA10, which contains the functional candidate gene HEXA. Three hundred and twenty kilobases that, besides HEXA, also contain ARIH1, BRUNOL6 and PARP6 were characterized and screened for polymorphisms. Genotyping of 38 SNPs in Holstein-Friesian animals from the UK (350 diseased and 270 controls) revealed two intronic SNPs that were associated with BSE incidence, with experiment-wise P-values of 3.5 x 10(-3) and 7.7 x 10(-3) respectively. Both SNPs were in strong linkage disequilibrium and the rare alleles had a protective effect. These alleles were contained in a haplotype dubbed 'UK-protective' that was significantly overrepresented in the controls with a permuted P-value of 2 x 10(-3). An association study in German Holstein animals (73 diseased and 627 controls) revealed an opposite effect of the 'UK-protective' haplotype in this population, i.e. it was overrepresented in the diseased animals, although not significant after correction for multiple testing. These findings indicate a causal variant for BSE susceptibility on BTA10 in linkage disequilibrium with the markers studied. Candidate gene analyses of the surrounding region and additional association studies will help to clarify the origin of the protective effects and to identify causal variants for BSE susceptibility on BTA10.

Übertragbare spongiforme Enzephalopathien bei Tieren – ein Update

Scrapie bei Schafen und Ziegen ist seit mehr als 250 Jahren bekannt. Dennoch rückte die Gruppe der transmissiblen spongiformen Enzephalopathien (TSE) erst nach dem Auftreten der bovinen spongiformen Enzephalopathie (BSE) im Vereinigten Königreich Ende der 1980er Jahre und dem einige Jahre später geführten Nachweis der übertragbarkeit des BSE-Erregers auf den Menschen in den 1990er Jahren vermehrt in das wissenschaftliche und öffentliche Interesse.Weltweit wurden mehr als 180000 BSE-Fälle bei Rindern diagnostiziert, davon die überwiegende Zahl im Vereinigten Königreich. Diese massive Infektion von Tieren mit dem BSE-Erreger erfolgte durch die unzureichende Inaktivierung und Verfütterung kontaminierter Futtermittel tierischen Ursprungs. Angesichts der seit 2001 zurückgehenden Zahl von BSE-Fällen in der gesamten EU und seit 2002 auch in Deutschland scheint das BSE-Geschehen bei Rindern heute unter Kontrolle. Anders verhält es sich mit den Scrapie-Fällen bei kleinen Wiederkäuern, deren endemische Verbreitung in den meisten EU-Mitgliedsstaaten durch die Einführung eines aktiven überwachungsprogramms aufgedeckt wurde. Dieses Programm führte auch zur Feststellung so genannter atypischer Scrapiefälle. Atypische Scrapie-Ausbrüche wurden bis dato in fast allen EU-Mitgliedsstaaten und zahlenmäßig häufiger als klassische Scrapie-Ausbrüche diagnostiziert. Daneben wurden mittlerweile auch zwei weitere BSE-Typen gefunden, die sich von den vom Vereinigten Königreich ausgangenen Fällen unterscheiden. Dieser Artikel fasst die aktuellen Erkenntnisse zur Epidemiologie, Pathogenese und Diagnostik von Scrapie und BSE zusammen.

Ifosfamide metabolites CAA, 4-OH-Ifo and Ifo-mustard reduce apical phosphate transport by changing NaPi-IIa in OK cells

Renal Fanconi syndrome occurs in about 1-5% of all children treated with Ifosfamide (Ifo) and impairment of renal phosphate reabsorption in about 20-30% of them. Pathophysiological mechanisms of Ifo-induced nephropathy are ill defined. The aim has been to investigate whether Ifo metabolites affect the type IIa sodium-dependent phosphate transporter (NaPi-IIa) in viable opossum kidney cells. Ifo did not influence viability of cells or NaPi-IIa-mediated transport up to 1 mM/24 h. Incubation of confluent cells with chloroacetaldehyde (CAA) and 4-hydroperoxyIfosfamide (4-OH-Ifo) led to cell death by necrosis in a concentration-dependent manner. At low concentrations (50-100 microM/24 h), cell viability was normal but apical phosphate transport, NaPi-IIa protein, and -mRNA expression were significantly reduced. Coincubation with sodium-2-mercaptoethanesulfonate (MESNA) prevented the inhibitory action of CAA but not of 4-OH-Ifo; DiMESNA had no effect. Incubation with Ifosfamide-mustard (Ifo-mustard) did alter cell viability at concentrations above 500 microM/24 h. At lower concentrations (50-100 microM/24 h), it led to significant reduction in phosphate transport, NaPi-IIa protein, and mRNA expression. MESNA did not block these effects. The effect of Ifo-mustard was due to internalization of NaPi-IIa. Cyclophosphamide-mustard (CyP-mustard) did not have any influence on cell survival up to 1000 microM, but the inhibitory effect on phosphate transport and on NaPi-IIa protein was the same as found after Ifo-mustard. In conclusion, CAA, 4-OH-Ifo, and Ifo- and CyP-mustard are able to inhibit sodium-dependent phosphate cotransport in viable opossum kidney cells. The Ifo-mustard effect took place via internalization and reduction of de novo synthesis of NaPi-IIa. Therefore, it is possible that Ifo-mustard plays an important role in pathogenesis of Ifo-induced nephropathy.

Impact of carbon dioxide versus air pneumoperitoneum on peritoneal cell migration and cell fate

BACKGROUND

Postoperative systemic immune function is suppressed after open abdominal surgery, as compared with that after minimally invasive abdominal surgery. As a first line of defense, peritoneal macrophages (PMo) and polymorphonuclear neutrophil granulocytes (PMNs) are of primary importance in protecting the body from microorganisms. Previous studies have shown changes in these cell populations over time after open versus laparoscopic surgery. This study aimed to investigate the dynamics of cell recruitment and clearance of peritoneal cells.

METHODS

Female NMRI mice (33 +/- 2 g) were randomly assigned to carbon dioxide (CO2) or air insufflation. Intravasal cells with phagocytic capabilities were selectively stained by intravenous injection of the fluorescent dye PKH26 24 h before surgery. Gas was insufflated into the peritoneal cavity through a catheter, and the pneumoperitoneum was maintained for 30 min. Peritoneal lavage was performed 1, 3, 8, or 24 h after surgery. Apoptotic cells were assessed by flow cytometry using a general caspase substrate.

RESULTS

The total peritoneal cell count did not differ between groups. The PKH26-positive PMo level was significantly increased after CO2, as compared with air, at 1 h and 24 h. The ratio of apoptotic PMo did not differ between the groups. In the peritoneal lavage, polymorphonuclear leukocytes (PMNs) were tripled in the air group, as compared with the CO2 group, whereas the ratio of apoptotic PMNs was significantly decreased. There was a higher fraction of PKH26-positive PMNs after air exposure, as compared with that after CO2.

CONCLUSIONS

Air exposure triggered a higher transmigration rate of PMNs from the blood compartment into the peritoneal cavity and decreased PMN apoptosis, as compared with CO2. The lower proportion of PKH26-positive peritoneal macrophages in the air group might have been attributable to a higher inflammatory stimulation than in the CO2 group, leading to increased emigration of PMo to draining lymph nodes. All the findings underscore a complex cell-specific regulation of cell recruitment and clearance in the peritoneal compartment.

Expression of Smoothelin in the Normal and the Overactive Human Bladder

PURPOSE

We established the expression pattern of smoothelin, a marker protein for contractile smooth muscle cells, in the human detrusor and investigated its possible impact on bladder overactivity.

MATERIALS AND METHODS

Detrusor samples of 13 overactive bladders (sensory urge and detrusor instability) were obtained before botulinum toxin injection and compared to those of 8 normally contractile, nonobstructed bladders obtained during radical cystectomy. Smoothelin mRNA expression patterns were investigated by Northern blot and variant specific reverse transcriptase-polymerase chain reaction as well as by quantitative reverse transcriptase-polymerase chain reaction on laser capture, microdissected smooth muscle. At the protein level smoothelin was investigated by standard and quantitative immunohistochemistry.

RESULTS

The bladder muscularis expressed vascular and visceral smoothelin isoforms, and 2 of the known splice variants. In the smooth muscle of patients with detrusor instability and sensory urge a significant 2.4 and 2.2-fold increase, respectively, in smoothelin variant 1 mRNA was observed in comparison to that of normal controls. Analyses at the smoothelin protein level confirmed significant up-regulation in these bladder dysfunctions by a factor of 2.3 and 1.8, respectively. No significant difference in smoothelin expression was observed between detrusor instability and sensory urge.

CONCLUSIONS

Increased expression of smoothelin in patients with detrusor instability and sensory urge implies that the etiology of these dysfunctions includes changes in myogenic parameters. In addition, our data support the new classification of the International Continence Society for overactive bladder proposing that sensory urge and detrusor instability represent a single clinical entity.

Strain typing of German transmissible spongiform encephalopathies field cases in small ruminants by biochemical methods

Following the implementation of a large scale transmissible spongiform encephalopathies (TSE) surveillance programme of small ruminants, evidence for a natural transmission of bovine spongiform encephalopathy (BSE) to a French goat has been found. During the years 2002-2004, a massive TSE rapid testing programme on >250,000 small ruminants was carried out in Germany. In this national survey, 186 scrapie-affected sheep were found which originated from 78 flocks. The majority of these cases were of the classical TSE type (115 sheep belonging to 14 outbreaks). However, 71 cases coming from 64 flocks were of the novel atypical scrapie type. According to the regulation EU 999/2001, all TSE cases in small ruminants have to be examined by strain typing methods to explore any possibility of the existence of BSE cases in the field sheep population. Here we report on a biochemical typing strategy (termed FLI-test), which includes the determination of molecular masses, antibody binding affinities and glycosylation pattern of the TSE induced abnormal prion protein. Based on this typing approach none of the analysed German classical TSE outbreaks (total number of analysed sheep: 36) displayed biochemical features indicative for a BSE infection. However, in two cases distinct but BSE-unrelated PrP(Sc) types were found, which alludes to the existence of different scrapie strains in the German sheep population.

Morphological features of cell death

Cell death is discriminated into two main forms: apoptosis and necrosis. In contrast to necrosis, apoptosis is a regulated, energy-dependent form of cell death leading to phagocytosis of cellular remnants by neighboring cells. Characteristic morphological features of these two forms of cell death will be discussed and correlated to underlying molecular mechanisms.

Atypical scrapie cases in Germany and France are identified by discrepant reaction patterns in BSE rapid tests

The intensified surveillance of scrapie in small ruminants in the European Union (EU) has resulted in a substantial increase of the number of diagnosed cases. Four rapid tests which have passed the EU evaluation for BSE testing of cattle are also recommended currently and used for the testing of small ruminants by the EU authorities. These tests include an indirect ELISA (cELISA), a colorimetric sandwich ELISA (sELISA I), a chemiluminescent sandwich ELISA (sELISA II), and a Western blot (WB). To this point, the majority of samples have been screened by using either sELISA I (predominantly in Germany) or WB (predominantly in France). In this study, it is shown that a number of the German and French scrapie cases show inconsistent results using rapid and confirmatory test methods. Forty-eight German sheep, 209 French sheep and 19 French goat transmissible spongiform encephalopathy (TSE) cases were tested. All cases were recognised by the sELISA I and either one of the confirmatory methods (scrapie-associated fibrils (SAF)-immunoblot or immunohistochemistry). Surprisingly, three rapid tests failed to detect a significant number of scrapie cases (29 in France and 24 in Germany). The possible reasons for these inconsistent reaction patterns of scrapie cases are discussed. Similar discrepancies have not been observed during rapid testing of cattle for BSE, the disease for which all diagnostic methods applied have been evaluated.

Decreased alveolar oxygen induces lung inflammation

Molecular mechanisms of the inflammatory reaction in hypoxia-induced lung injury are not well defined. Therefore, effects of alveolar hypoxia were studied in rat lungs, exposing rats to 10% oxygen over periods of 1, 2, 4, 6, and 8 h. An increase in the number of macrophages in bronchoalveolar lavage fluid of hypoxic animals was shown between 1 and 8 h. Extravasation of albumin was enhanced after 1 h and remained increased throughout the study period. NF-kappaB-binding activity as well as mRNA for TNF-alpha, macrophage inflammatory protein (MIP)-1beta, and monocyte chemoattractant protein (MCP)-1 were increased within the first 2 h of exposure to hypoxia. Hypoxia-inducible factor (HIF)-1alpha and intercellular adhesion molecule (ICAM)-1 mRNA were upregulated between 1 and 6 h. Elimination of alveolar macrophages by intratracheal application of liposome-encapsulated clodronate led to a decreased expression of NF-kappaB binding activity, HIF-1alpha, TNF-alpha, ICAM-1, and MIP-1beta. In summary, alveolar hypoxia induced macrophage recruitment, an increase in albumin leakage, and enhanced expression of inflammatory mediators, which were mainly macrophage dependent. Alveolar macrophages appear to have a prominent role in the inflammatory response in hypoxia-induced lung injury and the related upregulation of inflammatory mediators.

Role of alveolar epithelial ICAM-1 in lipopolysaccharide-induced lung inflammation

Intercellular adhesion molecule-1 (ICAM-1) is known to play a central role in lung inflammation. Limited information, however, is available regarding the expression and biological function of ICAM-1 in the alveolar epithelial compartment. The current report analyses the expression pattern of ICAM-1 in primary cultures of rat alveolar epithelial cells (AECs) and in the rat lung following instillation of bacterial endotoxin (lipopolysaccharide (LPS)) in order to better define the role of alveolar epithelial ICAM-1. AECs stimulated in vitro with LPS were evaluated for ICAM-1 and ICAM-1 messenger ribonucleic acid content. Adherence assays with neutrophils and macrophages were performed. Endotoxin-induced ICAM-1 upregulation on AECs was demonstrated in vivo by immunofluorescence staining. In addition, the effect of intratracheally-instilled anti-ICAM-1 was assessed. Significant upregulation of ICAM-1 occurred in vitro and in vivo on AECs after LPS stimulation. Adherence assays showed a 114% increase in adhesion of neutrophils to AECs. Antibody directed against ICAM-1 reduced this adhesion by 40%. A significant reduction in the number of neutrophils in bronchoalveolar lavage fluid and whole lung was seen under airway ICAM-1 blockade. These data indicate that intercellular adhesion molecule-1 participates in the inflammatory response to lipopolysaccharide-induced lung injury in the distal airways by interacting mainly with neutrophils.

Two splice variants of the Wilms' tumor 1 gene have distinct functions during sex determination and nephron formation

Alternative splicing of Wt1 results in the insertion or omission of the three amino acids KTS between zinc fingers 3 and 4. In vitro experiments suggest distinct molecular functions for + and -KTS isoforms. We have generated mouse strains in which specific isoforms have been removed. Heterozygous mice with a reduction of +KTS levels develop glomerulosclerosis and represent a model for Frasier syndrome. Homozygous mutants of both strains die after birth due to kidney defects. Strikingly, mice lacking +KTS isoforms show a complete XY sex reversal due to a dramatic reduction of Sry expression levels. Our data demonstrate distinct functions for the two splice variants and place the +KTS variants as important regulators for Sry in the sex determination pathway.

[Sweat gland carcinoma in the axillary area. A case report and review of the literature]

The sweat gland carcinoma is a rare tumor, representing in approximately 1% of primary skin lesions. In the literature 220 cases of sweat gland carcinomas have been presented over the last three decades. The medium age is 57 years, with an equal male-to-female distribution. Topographically, the tumor is located at the lower limbs (32.9%), the upper extremities (28%), and the head (26%). Involvement of the trunk is rare. Diagnosis can be complicated as the carcinoma is a rare entity, with no correlation of its histologic classification and biologic presentation. This can only implicate the difficulties in treatment.

Calsyntenin-1, a proteolytically processed postsynaptic membrane protein with a cytoplasmic calcium-binding domain

In a screen for proteins released from synapse-forming spinal cord neurons, we found the proteolytically cleaved N-terminal fragment of a transmembrane protein localized in the postsynaptic membrane of both excitatory and inhibitory synapses. We termed this protein calsyntenin-1, because it binds synaptic Ca2+ with its cytoplasmic domain. By binding Ca2+, calsyntenin-1 may modulate Ca2+-mediated postsynaptic signals. Proteolytic cleavage of calsyntenin-1 in its extracellular moiety generates a transmembrane stump that is internalized and accumulated in the spine apparatus of spine synapses. Therefore, the synaptic Ca2+ modulation by calsyntenin-1 may be subject to regulation by extracellular proteolysis in the synaptic cleft. Thus, calsyntenin-1 may link extracellular proteolysis in the synaptic cleft and postsynaptic Ca2+ signaling.

Embryoid bodies: an in vitro model of mouse embryogenesis

Embryonic stem (ES) cells are pluripotent cells isolated from the inner cell mass of blastocysts. ES cells are able to differentiate into the three primitive layers (endoderm, mesoderm and ectoderm) of the organism, including the germline. To study early stages of development, as well as to investigate the impact of a gene knock-out in vitro, ES cells are differentiated into three-dimensional structures called embryoid bodies, because of their ability to mimick post-implantation embryonic tissues. This review summarises the work on ES cell differentiation into haematopoietic and vascular cells, neuronal and glial cells, myocytes, and adipocytes, using this in vitro model of early embryogenesis. We also present the potential of this method to analyse the impact of genetic alterations in vitro.

Classical swine fever virus: clinical, virological, serological and hematological findings after infection of domestic pigs and wild boars with the field isolate "Spante" originating from wild boar

A classical swine fever virus (CSFV) field isolate originating from wild boar was investigated on its virulence in domestic pigs and wild boar. Three weaner pigs and two wild boars (yearlings) were intranasally inoculated with the isolate "Spante" and tested for clinical, virological, hematological and serological findings until day 31 after infection (p. i.). One day p. i. the piglets were put in contact to three sentinel pigs. During a period of 31 d neither the domestic pigs nor the wild boars showed clinical signs specific for CSF. Two infected weaner pigs became transiently viraemic, transmitted CSFV in nasal secretions, showed a slight leukopenia and reacted serologically positive. The contact infection resulted in a viraemia in two sentinel piglets on day 30. Only one contact animal developed antibodies. None of the wild boars became viraemic, excreted CSFV in nasal secretions or developed antibodies. The CSFV isolate "Spante" represents a low virulent virus. Referring to a significant higher percentage of virologically positive tissue samples after nested PCR compared with the virus isolation, persistence of CSFV is discussed.

Differential subcellular localization of ENaC subunits in mouse kidney in response to high- and low-Na diets

Previous electrophysiological experiments on renal cortical collecting ducts indicated that dietary sodium intake and variations in aldosterone plasma levels regulate the abundance of functional epithelial Na channels (ENaC) in the apical plasma membrane. In mouse kidney we investigated by immunohistochemistry whether feeding for 3 wk a diet with high (3% Na) and low (0.05% Na) Na content influences the distribution pattern of ENaC. In mice of all experimental groups, ENaC was apparent in cells from the late portion of the distal convoluted tubule (DCT2) down to the medullary collecting duct (CD). In mice on a high-Na diet (plasma aldosterone: 40.8 +/- 2.0 ng/dl), the alpha-subunit was undetectable, and the beta- and gamma-ENaC were detected in the cytoplasm, but not in the apical plasma membrane of the cells. In contrast, in mice on a low-Na diet (plasma aldosterone: 93.6 +/- 9.3 ng/dl) all three ENaC subunits were displayed in the subapical cytoplasm and in the apical membrane of DCT2, connecting tubule (CNT), and, although less prominent, in cortical CD cells. Apical plasma membrane immunostaining progressively decreased along the cortical CD, simultaneously with increasing cytoplasmic staining for beta- and gamma-ENaC. Thus our data on mice adapted to moderately low and high Na intake suggest that regulation of ENaC function in vivo involves shifts of beta- and gamma-subunits from the cytoplasm to the apical plasma membrane and vice versa, respectively. The insertion of these subunits into the apical plasma membrane coincides with upregulation of the alpha-subunit and its insertion into the apical plasma membrane.

Lipopolysaccharide induces functional ICAM-1 expression in rat alveolar epithelial cells in vitro

Lipopolysaccharide (LPS)-induced lung inflammation is known to increase pulmonary intercellular adhesion molecule-1 (ICAM-1) expression. In the present study, L2 cells, a cell line of alveolar epithelial cells, were stimulated with LPS, and ICAM-1 expression was studied. ICAM-1 protein on L2 cells peaked at 6 (38% increase; P < 0.01) and 10 (48% increase; P < 0.001) h after stimulation with Escherichia coli and Pseudomonas aeruginosa LPS, respectively. ICAM-1 mRNA expression was markedly increased, with a peak at 2-4 (E. coli) and 4-6 (P. aeruginosa) h. Adherence assays of neutrophils to LPS-stimulated L2 cells showed a threefold increase in adherence (P < 0.001). Pretreatment of the neutrophils with anti-lymphocyte function-associated antigen-1 and anti-Mac-1 antibodies reduced adherence by 54% (P < 0.001). Analysis of immunofluorescence staining for ICAM-1 showed an exclusive apical expression of ICAM-1. These results indicate that LPS upregulates functional active ICAM-1 on the apical part of the membrane in rat pneumocytes.

Bacterial population of chronic crural ulcers: is there a difference between the diabetic, the venous, and the arterial ulcer?

BACKGROUND

At the Surgical Department of Surgery of the University Hospital Würzburg microbiological examinations were performed of the ulcer grounds from patients with diabetic-neuropathic, diabetic-ischemic, venous, and arterial leg ulcers. The aim of the examination was to evaluate possible differences in the healing process of these ulcers based on the knowledge of their bacterial populations.

PATIENTS AND METHODS

In a period of four months, 63 patients were consecutively examined by taking a bacteriological swab of their ulcer area. The healing process of their wounds was followed and related to the impact of bacterial colonisation and clinical signs of infection.

RESULTS

95% of the venous and arterial leg ulcers had a positive smear, whereas only 70% of diabetic ulcers were positive for bacterial growth. Bacterial population of the three ulcer entities, however did not differ significantly. 100% of the clinically infected venous and arterial ulcers but only 80% of the diabetic wounds revealed a positive smear. On the other hand, only 22% of the venous ulcers with a positive smear developed a clinical infection in contrast to 70% of the arterial and diabetic. Venous ulcers showed only in a few patients prolonged healing, even in cases of marked bacterial contamination. Despite of clinical signs of infection however, diabetic wounds sometimes did not reveal a positive wound smear (20%). All infected venous, but only 20% of the infected ischemic ulcers healed satisfactorily. Arterial wounds with no bacterial growth healed significantly better than contaminated wounds. This difference was not significant in the other entities. Radical removal of the infection by minor amputation increased the healing rate in diabetic ulcers over 80%, whereas ischemic wounds did not profit from this therapy.

CONCLUSIONS

A positive bacterial wound smear is not inevitably correlated with a protracted leg ulcer healing. Nevertheless a fulminant infection often developed in diabetic ulcers despite the initial inability to demonstrate bacterial growth. In order to start antibiotic treatment as early as possible, a wound smear should be obtained routinely from patients with diabetic ulcers. In chronic venous ulcers, a routine swab does not appear to be indicated as it bears no clinical consequences. The same applies to patients with surgically fully treated peripheral arterial occlusive disease. As ischemia presents the limiting factor, antibiotic therapy in case of infection will not prevent imminent amputation.

Effect of streptolysin O on the microelasticity of human platelets analyzed by atomic force microscopy

Atomic force microscopy (AFM) has been shown to be a suitable tool to probe biophysical properties of cells and cell fragments. We analysed biophysical alterations of human platelets by AFM using streptolysin O (SLO) as a model for pore forming proteins. Permeabilization of platelet membrane by SLO was confirmed by transmission electron and confocal microscopy. Using force volume imaging combined with FIEL analysis we were able to show dynamically the increase in the elasticity of platelets during the pore formation by SLO and could correlate the viscoelasticity to the morphology of platelets. Stabilizing the actin cytoskeleton by phalloidin resulted in partial restoration of the elasticity indicating that loss of stability in platelets by SLO is mediated by alterations of both plasma membrane and cytoskeleton.

cAMP-dependent and -independent downregulation of type II Na-Pi cotransporters by PTH

Parathyroid hormone (PTH) leads to the inhibition of Na-Pi cotransport activity and to the downregulation of the number of type II Na-Pi cotransporters in proximal tubules, as well as in opossum kidney (OK) cells. PTH is known also to lead to an activation of adenylate cyclase and phospholipase C in proximal tubular preparations, as well as in OK cells. In the present study, we investigated the involvement of these two regulatory pathways in OK cells in the PTH-dependent downregulation of the number of type II Na-Pi cotransporters. We have addressed this issue by using pharmacological activators of protein kinase A (PKA) and protein kinase C (PKC), i.e., 8-bromo-cAMP (8-BrcAMP) and beta-12-O-tetradecanoylphorbol 13-acetate (beta-TPA), respectively, as well as by the use of synthetic peptide fragments of PTH that activate adenylate cyclase and/or phospholipase C, i.e., PTH-(1-34) and PTH-(3-34), respectively. Our results show that PTH signal transduction via cAMP-dependent, as well as cAMP-independent, pathways leads to a membrane retrieval and degradation of type II Na-Pi cotransporters and, thereby, to the inhibition of Na-Pi cotransport activity. Thereby, the cAMP-independent regulatory pathway leads only to partial effects (approximately 50%).

Induction and nuclear translocation of hypoxia-inducible factor-1 (HIF-1): heterodimerization with ARNT is not necessary for nuclear accumulation of HIF-1alpha

Hypoxia-inducible factor-1 (HIF-1) is a master regulator of mammalian oxygen homeostasis. HIF-1 consists of two subunits, HIF-1alpha and the aryl hydrocarbon receptor nuclear translocator (ARNT). Whereas hypoxia prevents proteasomal degradation of HIF-1alpha, ARNT expression is thought to be oxygen-independent. We and others previously showed that ARNT is indispensable for HIF-1 DNA-binding and transactivation function. Here, we have used ARNT-mutant mouse hepatoma and embryonic stem cells to examine the requirement of ARNT for accumulation and nuclear translocation of HIF-1alpha in hypoxia. As shown by immunofluorescence, HIF-1alpha accumulation in the nucleus of hypoxic cells was independent of the presence of ARNT, suggesting that nuclear translocation is intrinsic to HIF-1alpha. Co-immunoprecipitation of HIF-1alpha together with ARNT could be performed in nuclear extracts but not in cytosolic fractions, implying that formation of the HIF-1 complex occurs in the nucleus. A proteasome inhibitor and a thiol-reducing agent could mimic hypoxia by inducing HIF-1alpha in the nucleus, indicating that escape from proteolytic degradation is sufficient for accumulation and nuclear translocation of HIF-1alpha. During biochemical separation, both HIF-1alpha and ARNT tend to leak from the nuclei in the absence of either subunit, suggesting that heterodimerization is required for stable association within the nuclear compartment. Nuclear stabilization of the heterodimer might also explain the hypoxically increased total cellular ARNT levels observed in some of the cell lines examined.

Preparation of basal cell membranes for scanning probe microscopy

Scanning probe microscopy has the potential for investigating membranes in a physiological environment. We prepared with a lysis-squirting protocol basal cell membranes, that are suitable for scanning probe microscopy. Investigations using atomic force microscopy under liquid revealed cellular filaments which correlated perfectly with fluorescently stained actin filaments. Globular structures with a diameter as little as 10 nm could be resolved by stripping cytoplasmic components from the membranes. Therefore, cytoplasmic sides of supported basal cell membranes prove useful to gain high resolution with scanning probe microscopy in studies of plasma membrane associated structures and processes under buffer solution.

Light-harvesting complex II in monocomponent and mixed lipid-protein monolayers

Monomolecular layers at the air-water interface were formed directly with isolated largest light-harvesting pigment-protein complex of Photosystem II (LHC II) or out of egg yolk lecithin (EYL) liposomes containing incorporated LHC II. Pure protein monolayers showed a mean area of 1400 A2 per molecule at the air-water interface. Monolayers were deposited onto glass slides by means of Langmuir-Blodgett (LB) technique. Chlorophyll fluorescence of LHC II-LB and EYL-LHC II-LB films proved energetic coupling of chlorophyll a and b, thus indicating native conformation of LHC II within the monolayers. Scanning force microscopy (SFM) revealed ring-like structures formed in monocomponent protein layers as well as in mixed protein-lipid films. These results suggest that a structural arrangement of LHC II is favoured in a lipid environment but that the protein has itself a strong tendency for structural complex rearrangement in our system.

Atomic force microscopy detects changes in the interaction forces between GroEL and substrate proteins

The structure of the Escherichia coli chaperonin GroEL has been investigated by tapping-mode atomic force microscopy (AFM) under liquid. High-resolution images can be obtained, which show the up-right position of GroEL adsorbed on mica with the substrate-binding site on top. Because of this orientation, the interaction between GroEL and two substrate proteins, citrate synthase from Saccharomyces cerevisiae with a destabilizing Gly-->Ala mutation and RTEM beta-lactamase from Escherichia coli with two Cys-->Ala mutations, could be studied by force spectroscopy under different conditions. The results show that the interaction force decreases in the presence of ATP (but not of ATPgammaS) and that the force is smaller for native-like proteins than for the fully denatured ones. It also demonstrates that the interaction energy with GroEL increases with increasing molecular weight. By measuring the interaction force changes between the chaperonin and the two different substrate proteins, we could specifically detect GroEL conformational changes upon nucleotide binding.

Parathyroid hormone leads to the lysosomal degradation of the renal type II Na/Pi cotransporter

We have studied the involvement of proteolytic pathways in the regulation of the Na/Pi cotransporter type II by parathyroid hormone (PTH) in opossum kidney cells. Inhibition of lysosomal degradation (by leupeptin, ammonium chloride, methylamine, chloroquine, L-methionine methyl ester) prevented the PTH-mediated degradation of the transporter, whereas inhibition of the proteasomal pathway (by lactacystin) did not. Moreover it was found (i) that whereas lysosomal inhibitors prevented the PTH-mediated degradation of the transporter they did not prevent the PTH-mediated inhibition of the Na/Pi cotransport and (ii) that treating opossum kidney cells with lysosomal inhibitors led to an increased expression of the transporter without any concomitant increase in the Na/Pi cotransport. Further analysis by subcellular fractionation and morphological techniques showed (i) that the Na/Pi cotransporter is constitutively transported to and degraded within late endosomes/lysosomes and (ii) that PTH leads to the increased degradation of the transporter in late endosomes/lysosomes.

Parathyroid hormone-dependent degradation of type II Na+/Pi cotransporters

Parathyroid hormone (PTH) inhibits proximal tubular brush border membrane Na+/Pi cotransport activity; this decrease in the transport activity was found to be associated with a decrease in type II Na+/Pi cotransporter protein content in rat brush border membranes. In the present study we investigated the PTH-dependent regulation of the type II Na+/Pi cotransporter in opossum kidney cells, a previously established model to study cellular mechanisms involved in the regulation of proximal tubular Na+/Pi cotransport. We transfected opossum kidney cells with a cDNA coding for NaPi-2 (rat renal type II Na+/Pi cotransporter). This allowed the study of PTH-dependent regulation of the transfected NaPi-2 and of the corresponding intrinsic cotransporter (NaPi-4). The results show (i) that the intrinsic and the transfected cotransporters are functionally (transport) and morphologically (immunofluorescence) localized at the apical membrane, (ii) that the intrinsic as well as the transfected Na+/Pi cotransport activities are inhibited by PTH, (iii) that PTH leads to a retrieval of both cotransporters from the apical membrane, (iv) that both cotransporters are rapidly degraded in response to PTH, and (v) that the reappearance/recovery of type II Na+/Pi cotransporter protein and function from PTH inhibition requires de novo protein synthesis. These results document that PTH leads to a removal of type II Na+/Pi cotransporters from the apical membrane and to their subsequent degradation.

Adenovirus-mediated gene transfer in neurons: construction and characterization of a vector for heterologous expression of the axonal cell adhesion molecule axonin-1

By homologous recombination, a first-generation adenovirus-based gene transfer vector, AdCMVax-1, was constructed as a means of manipulating the expression level of the axonal cell adhesion molecule axonin-1 in neurons and glial cells. AdCMVax-1 harbours the entire coding region of the chicken axonin-1 cDNA under the transcriptional control of the Cytomegalovirus enhancer/promoter in the early-region 1 of the viral genome. Characterization of AdCMVax-1 in vitro revealed highly efficient gene transfer and expression of recombinant axonin-1 in neurons and glial cells of dissociated rat dorsal root ganglia. Similar to its native counterpart, virus-derived axonin-1 was detected on the cell body, neurites, and growth cones of transduced neurons, occurred in a secreted and membrane-associated form, and could be cleaved from the membrane with phosphatidylinositol-specific phospholipase C. Functional characterization of recombinant axonin-1 revealed the same binding properties as previously reported for native axonin-1 isolated from the vitreous fluid of chicken embryos. In vivo gene transfer was studied by stereotactic injection of AdCMVax-1 in the dentate gyrus of the hippocampus and the facial nucleus in the brainstem of adult Wistar rats and revealed high level expression of recombinant axonin-1 in a subset of hippocampal neurons and motor neurons in the facial nucleus.

Cell adhesion molecules NgCAM and axonin-1 form heterodimers in the neuronal membrane and cooperate in neurite outgrowth promotion

The axonal surface glycoproteins neuronglia cell adhesion molecule (NgCAM) and axonin-1 promote cell-cell adhesion, neurite outgrowth and fasciculation, and are involved in growth cone guidance. A direct binding between NgCAM and axonin-1 has been demonstrated using isolated molecules conjugated to the surface of fluorescent microspheres. By expressing NgCAM and axonin-1 in myeloma cells and performing cell aggregation assays, we found that NgCAM and axonin-1 cannot bind when present on the surface of different cells. In contrast, the cocapping of axonin-1 upon antibody-induced capping of NgCAM on the surface of CV-1 cells coexpressing NgCAM and axonin-1 and the selective chemical cross-linking of the two molecules in low density cultures of dorsal root ganglia neurons indicated a specific and direct binding of axonin-1 and Ng-CAM in the plane of the same membrane. Suppression of the axonin-1 translation by antisense oligonucleotides prevented neurite outgrowth in dissociated dorsal root ganglia neurons cultured on an NgCAM substratum, indicating that neurite outgrowth on NgCAM substratum requires axonin-1. Based on these and previous results, which implicated NgCAM as the neuronal receptor involved in neurite outgrowth on NgCAM substratum, we concluded that neurite outgrowth on an NgCAM substratum depends on two essential interactions of growth cone NgCAM: a trans-interaction with substratum NgCAM and a cis-interaction with axonin-1 residing in the same growth cone membrane.

Intracellular signaling is changed after clustering of the neural cell adhesion molecules axonin-1 and NgCAM during neurite fasciculation

Neural cell adhesion molecules of the immunoglobulin/fibronectin type III family on axons have been implicated in promotion of neurite outgrowth, fasciculation, and the mediation of specific cell adhesion. The present study demonstrates that two of these molecules on dorsal root ganglion neurons are associated with distinct protein kinases, axonin-1 with the src-related nonreceptor tyrosine kinase fyn and NgCAM with a casein kinase II-related activity and a serine/ threonine kinase related to S6 kinase. When neurites grew without contacts involving axonin-1 and NgCAM, strong fyn kinase activity was associated with axonin-1, whereas the NgCAM-associated kinase activities were low. Clustering of axonin-1 with NgCAM induced by the formation of cell-cell contacts correlated with a reduction of the axonin-1-associated fyn activity and an increased phosphorylation of NgCAM by the associated casein kinase II-related activity. Thus, axonin-1 and NgCAM trigger distinctive intracellular signals during in vitro differentiation depending on their state of association.