Hyaluronic acid/chitosan multilayer coatings on neuronal implants for localized delivery of siRNA nanoplexes

Binding, stabilizing and promoting cellular uptake of siRNA are all critical efforts in creating matrices for the localized delivery of siRNA molecules to target cells. In this study, we describe the generation of chitosan imidazole/siRNA nanoplexes (NPs) embedded in nano scope polyelectrolyte multilayers (PEMs) composed of hyaluronic acid and chitosan for sustained and localized drug delivery. Regular PEM build-up, successful integration of NPs and controlled release under physiological conditions were shown. Biological efficacy was evaluated in neuronal cell culture concerning cell adhesion, viability, NPs uptake and gene silencing. The additionally shown biological functionalization of neuronal implants possesses potential for future applications in the field of regenerative medicine and treatment of spinal cord injuries.

Alkalinizing effect of NaHCO₃ with and without glucose when administered orally to euhydrated neonatal dairy calves

The use of oral rehydration solutions (ORS) is well established as an effective treatment to correct water-, electrolyte-, and acid-base balance in diarrheic calves. The main ingredients of a commercial ORS are Na, glucose, and alkalinizing agents, such as NaHCO3. Particular importance is attributed to the combination of glucose and Na at a specific ratio to optimize intestinal sodium, and thereby water uptake, through the sodium-glucose co-transport. Enhancing intestinal Na absorption by combining glucose and Na in an ORS has the potential to improve the alkalinizing effect of an ORS according the strong ion theory. The objective of this study was to investigate the effect of glucose on the alkalinizing effect of NaHCO3 when administered orally. Nine healthy neonatal Holstein-Friesian calves underwent 3 oral treatments with 2-L solutions of NaHCO3 (150 mmol/L), glucose (300 mmol/L), and glucose + NaHCO3 (300 mmol/L + 150 mmol/L, respectively) in randomized order. Arterial and venous blood was obtained before treatment and in 30-min intervals thereafter for blood gas analysis and determination of plasma protein and electrolyte concentrations. Urine was collected volumetrically to determine urine volume, osmolality, pH, net acid excretion, and renal Na excretion after treatment. Plasma volume changes were extrapolated from plasma protein concentration changes. Treatment and time effects were tested with repeated measures ANOVA. Only subtle differences between oral administration of NaHCO3, with and without glucose, were observed for the change of the standard HCO3 concentration relative to baseline. No differences in plasma Na, plasma volume expansion, renal Na, net base excretion, urine volume, or pH could be identified between animals treated orally with NaHCO3 with and without glucose. Similarly, no differences in blood glucose concentration, plasma volume expansion, urine volume, or renal glucose excretion were observed in the 8h after treatment when comparing oral glucose treatment with and without NaHCO3. Our results indicate that combination of NaHCO3 with glucose in a hypertonic ORS only had a minor effect on the alkalinizing effect of NaHCO3, which is unlikely to be of clinical relevance. The combination of NaHCO3 and glucose neither improved Na, glucose, nor water absorption in euhydrated neonatal dairy calves, questioning the relevance of a specific ratio between Na and glucose in ORS for calves.

Long-term outcome of children with acute cerebellitis

BACKGROUND

Acute cerebellitis (AC) is characterized by cerebellar symptoms and magnetic resonance imaging (MRI) changes primarily confined to the cerebellum.

OBJECTIVE

To analyze the neurological and cognitive long-term outcome of children with AC.

METHODS

Children with AC diagnosed by typical clinical features and MRI findings were included in this retrospective study. Medical charts were reviewed and neurological deficits were assessed by neurological examination or by the expanded disability status scale telephone interview. Cognitive outcome was evaluated with a parental questionnaire (Kognitive Probleme bei Kindern und Jugendlichen).

RESULTS

A total of 11 children (6 boys, 5 girls; age range: 3 years to 14 years and 10 months) were included. Of them, six children had a severe disease manifestation including mental status changes and neurological symptoms. Of the rest, two children had a moderate and three children had a mild form of AC. MRI of the cerebellum was obtained in the acute phase revealing signal alterations with different patterns. The average follow-up period was 4 years and 4 months. A complete recovery was observed in five children. Neurological sequelae were reported in five children ranging from ataxia to mild tremor. Cognitive deficits were found in six patients. The affected areas of cognition did include spatial visualization ability, language skills, and concentration.

CONCLUSION

Neurological and cognitive sequelae are common in children with AC and underline the role of the cerebellum in cognition.

Blood parameters and corneal-reflex of finishing pigs with and without lung affections observed post mortem in two abattoirs stunning with CO₂

In two pig abattoirs of different slaughter capacities, the stunning efficacy of CO2 on finishing pigs with and without pneumonic lesions (observed post mortem) was reflected against the corneal-reflex and blood parameters (blood pH, pCO2 and pO2) from individual finishers. Stunning duration was 120 s (abattoir A) and 90 s (abattoir B), respectively. Pneumonia in finisher pigs is frequently observed during post mortem inspection, which may raise concerns about a delay of unconsciousness because of hampered gas exchange in the lungs. The aim of this study was to examine possible pneumonia consequences for stunning efficacy under commercial conditions. For that, corneal reflex, O2 and CO2 partial pressure in the blood as well as blood pH were measured in 2650 finishers from abattoir A and 2100 from abattoir B. The partial pressure of O2 after stunning accounted to about 3 kPa, the partial pressure of CO2 was found at levels of about 24 kPa in abattoir A (after 120 s CO2 exposure) and 17.5 kPa in abattoir B (after 90 s CO2 exposure). In abattoir A, the blood pH was at 6.9, and at 7.0 in abattoir B. The corneal reflex was observed in 6.2% of pigs in abattoir A and 17.1% of pigs in abattoir B. A correlation between pneumonic lesions and blood status was not observed. However, for some individual farms, a significant correlation between pneumonia and corneal reflex was observed.

Interaction of CO and deuterium with bimetallic, monolayer Pt-island/film covered Ru(0001) surfaces

The adsorption properties of structurally well defined bimetallic Pt/Ru(0001) surfaces, consisting of a Ru(0001) substrate partly or fully covered by monolayer Pt islands or a monolayer Pt film, were studied by temperature programmed desorption (TPD) using CO and deuterium as probe molecules. Additionally, the adsorption of CO was investigated by infrared reflection absorption spectroscopy (IRAS). The presence of the pseudomorphic platinum islands or monolayer film leads to considerable modifications of the adsorption properties for both adsorbates, both on the Pt covered and, to a smaller extent, on the bare Ru part of the surfaces. In addition to distinct weakly bound adspecies, which are adsorbed on the monolayer Pt islands, we find unique contributions from island edge desorption, from spill-over processes during the desorption run, and a general down-shift of the peak related to desorption from Pt-free Ru(0001) areas with increasing Pt coverage. These effects, which we consider as characteristic for adsorption on bimetallic surfaces with large contiguous areas of the respective types, are discussed in detail.

Design and capabilities of an experimental setup based on magnetron sputtering for formation and deposition of size-selected metal clusters on ultra-clean surfaces

The design and performance of an experimental setup utilizing a magnetron sputtering source for production of beams of ionized size-selected clusters for deposition in ultra-high vacuum is described. For the case of copper cluster formation the influence of different source parameters is studied and analyzed. Size-selected clusters are deposited on substrates and the efficiency of an electrostatic quadrupole mass selector is tested. Height analysis using atomic force microscopy (AFM) demonstrates relative standard size deviations of 7%-10% for the particles of various sizes between 6 nm and 19 nm. Combined analysis by AFM and transmission electron microscopy reveals that the clusters preserve almost spherical shape after the deposition on amorphous carbon substrates. Supported nanoparticles of a few nanometres in diameter have crystalline structure with a face-centered cubic (fcc) lattice.

Inosine, not adenosine, initiates endothelial glycocalyx degradation in cardiac ischemia and hypoxia

Ischemia/reperfusion and hypoxia/reoxygenation of the heart both induce shedding of the coronary endothelial glycocalyx. The processes leading from an oxygen deficit to shedding are unknown. An involvement of resident perivascular cardiac mast cells has been proposed. We hypothesized that either adenosine or inosine or both, generated by nucleotide catabolism, attain the concentrations in the interstitial space sufficient to stimulate A3 receptors of mast cells during both myocardial ischemia/reperfusion and hypoxia/reoxygenation. Isolated hearts of guinea pigs were subjected to either normoxic perfusion (hemoglobin-free Krebs-Henseleit buffer equilibrated with 95% oxygen), 20 minutes hypoxic perfusion (buffer equilibrated with 21% oxygen) followed by 20 minutes reoxygenation, or 20 minutes stopped-flow ischemia followed by 20 minutes normoxic reperfusion (n = 7 each). Coronary venous effluent was collected separately from so-called transudate, a mixture of interstitial fluid and lymphatic fluid appearing on the epicardial surface. Adenosine and inosine were determined in both fluid compartments using high-performance liquid chromatography. Damage to the glycocalyx was evident after ischemia/reperfusion and hypoxia/reoxygenation. Adenosine concentrations rose to a level of 1 μM in coronary effluent during hypoxic perfusion, but remained one order of magnitude lower in the interstitial fluid. There was only a small rise in the level during postischemic perfusion. In contrast, inosine peaked at over 10 μM in interstitial fluid during hypoxia and also during reperfusion, while effluent levels remained relatively unchanged at lower levels. We conclude that only inosine attains levels in the interstitial fluid of hypoxic and postischemic hearts that are sufficient to explain the activation of mast cells via stimulation of A3-type receptors.

Plasma potassium-lowering effect of oral glucose, sodium bicarbonate, and the combination thereof in healthy neonatal dairy calves

Hyperkalemia is a common complication in neonatal diarrheic dairy calves and is corrected by administration of glucose or sodium bicarbonate. Although the hypokalemic effect of glucose is well established in other species, controversial results are reported for sodium bicarbonate. Our objective was to study the effect and mechanism of action of glucose and sodium bicarbonate on the potassium homeostasis of healthy neonatal dairy calves. Nine healthy neonatal Holstein-Friesian calves underwent 3 oral treatments with 2L of NaHCO(3) (150 mmol/L), glucose (300 mmol/L), and glucose+NaHCO(3) solution (300 mmol/L+150 mmol/L) in randomized order. Blood was obtained before treatment (T(0)) and at 30-min intervals thereafter. Changes between each time point and T(0) were determined for all parameters. Urine was collected volumetrically to determine total renal potassium excretion over an 8-h posttreatment period. Plasma volume changes were extrapolated from changes in plasma protein concentration. Treatment and time effects were tested with repeated-measures ANOVA. Multivariate stepwise regression analysis using dummy variable coding was conducted to identify associations between changes in plasma potassium concentration ([K]) and changes in plasma glucose concentration ([glucose]), blood base excess, and plasma volume. Oral glucose and sodium bicarbonate treatments decreased [K] by 25 and 19%, respectively, whereas the combination of both compounds caused an intermediate [K] decline (22%). For the glucose treatment, the decline in [K] was only associated with changes in plasma [glucose] (partial R(2)=0.19). In NaHCO(3)-treated calves, [K] decline was associated with change of extracellular volume (partial R(2)=0.31) and blood base excess (partial R(2)=0.19). When glucose and NaHCO(3) were combined, [K] decline was associated with changes in plasma volume (partial R(2)=0.30), BE (R(2)=0.22), and [glucose] (partial R(2)=0.03). Our results indicate that glucose lowers plasma [K] mainly through an insulin-dependent intracellular translocation of K, whereas NaHCO(3) causes hypokalemia through hemodilution followed by intracellular translocation of K caused by the strong ion effect. The combination of glucose and NaHCO(3) at the dosage used in this study does not have an additive hypokalemic effect. When combined, hemodilution and strong ion effect have the strongest effect on plasma [K], whereas the insulin-dependent effect of glucose appears to be blunted.

Shedding of the coronary endothelial glycocalyx: effects of hypoxia/reoxygenation vs ischaemia/reperfusion

BACKGROUND

Vascular endothelium is covered by a glycocalyx. Damage to the glycocalyx after systemic inflammation or ischaemia/reperfusion contributes to increased vascular permeability and leucocyte adhesion. The underlying mechanisms leading to ischaemia/reperfusion-induced glycocalyx shedding are incompletely understood, in terms of lack of oxygen, absence of flow, or return of oxygen.

METHODS

Isolated guinea pig hearts perfused with Krebs-Henseleit buffer at 37°C underwent 20 min of either stopped-flow ischaemia or hypoxic perfusion with subsequent reperfusion/reoxygenation (n = 6 each). Hearts perfused with normoxic buffer served as time controls. Epicardial transudate was collected to assess coronary net fluid filtration, colloid extravasation, and histamine release by mast cells. Syndecan-1 and heparan sulphate were measured in coronary effluent, together with lactate, purines, and the release of mast-cell tryptase β. Additional hearts were perfusion-fixed to visualize the glycocalyx.

RESULTS

Both ischaemia and hypoxia with reperfusion/reoxygenation resulted in significant increases in net fluid filtration (P < 0.05) and release of syndecan-1 and heparan sulphate in coronary effluent. These effects were already seen with the onset of hypoxic perfusion. Histamine was released during hypoxia and reoxygenation and also reperfusion, as was tryptase β, and high concentrations of adenosine (>1 µmol litre⁻¹, hypoxia group) and inosine (> 7 µmol litre⁻¹, ischaemia group) were measured in effluent (P < 0.05). Damage to the coronary glycocalyx was evident upon electron microscopy.

CONCLUSIONS

Both ischaemic and hypoxic hypoxia initiate glycocalyx degradation, promoting an increase in permeability. A contributing mechanism could be purine-mediated degranulation of resident mast cells, with liberated tryptase β acting as potential 'sheddase'.

Serious head injury in young children: birth trauma versus non-accidental head injury

Birth injury of the skull and central nervous system can be a complication of a difficult delivery, especially following forceps or vacuum-assisted delivery. Birth trauma of the head can also mimic the appearance of a non-accidental head injury and is therefore an important differential diagnosis. We report on two young infants with serious head injuries. The difficult differential diagnosis birth trauma versus non-accidental head injury is discussed and the necessity for cooperation between clinicians, forensic doctors and specialized neuroradiologists is emphasized.

Recurrent upper motor neuron facial weakness of possible epileptic etiology: a case report

We report on an otherwise healthy infant who presented with clusters of alternating central facial nerve paresis. At 11 months of age, the patient showed intermittent facial asymmetry compatible with right-sided upper motor neuron facial paresis and accompanying incomplete upper motor neuron hypoglossal paresis. Laboratory work-up and imaging studies did not reveal signs of infection, infarction or structural lesions, and after one week, symptoms spontaneously resolved. Similar episodes affecting alternate sides were noted at ages of 17, 27 and 49 months lasting for 4-14 days. At 49 months, EEG showed right temporo-occipital benign sharp waves with activation during drowsiness and sleep. A diagnosis of benign focal epilepsy with negative motor phenomena was made. She is now 60 months old and no further episodes have occurred without antiepileptic treatment. Ictal orofacial phenomena are the clinical hallmark of benign focal epilepsy with centro-temporal sharp waves (BECTS). As in our patient, negative epileptic motor phenomena frequently lead to a broad diagnostic work-up. In infants presenting with episodic central facial nerve paresis, the possibility of negative epileptic motor phenomena should be considered.

Chitosan/siRNA nanoparticles biofunctionalize nerve implants and enable neurite outgrowth

Microstructured 20 μm thick polymer filaments used as nerve implants were loaded with chitosan/siRNA nanoparticles to promote nerve regeneration and ensure local delivery of nanotherapeutics. The stable nanoparticles were rapidly internalized by cells and did not affect cell viability. Target mRNA was successfully reduced by 65-75% and neurite outgrowth was enhanced even in an inhibitory environment. This work, thus, supports the application of nanobiofunctionalized implants as a novel approach for spinal cord and nerve repair.

['Cases against KiSS': a diagnostic algorithm for children with torticollis]

In 1991, Biedermann coined the term "kinetic imbalance due to suboccipital strain" ("KiSS-syndrome"). He assumed a functional abnormality of the suboccipital-high cervical spine, resulting in positional preference of the infant;s head. A broad spectrum of symptoms and complaints have been attributed to "KiSS-Syndrome". Patients are advised to undergo manual therapy, with pressure applied locally in order to readjust the cervical spine. Life threatening side-effects have been published repeatedly. We present two infants with brain tumours who developed torticollis and further neurological findings such as ataxia and reflex differences. In both cases, symptoms caused by the tumour were interpreted as "KiSS-syndrome", and appropriate diagnostics and therapy were delayed for months. There is no scientific evidence for the actual existence of "KiSS-syndrome" as a clinical entity or for the positive effects of manual therapy. Approximately 12% of all infants <12 months show a positional preference of the head, about 8% present with body asymmetry. Whereas most cases are benign, there is a long list of serious differential diagnoses for torticollis in infants. We give an updated review of the literature regarding "KiSS-Syndrome" and discuss the differential diagnostics in infants with torticollis.

Scheie syndrome: enzyme replacement therapy does not prevent progression of cervical myelopathy due to spinal cord compression

Hurler-Scheie syndrome is caused by alpha-l-iduronidase deficiency. Enzyme replacement therapy (ERT) can improve physical capacity and reduces organomegaly. However, the effect on bradytrophic connective tissue is limited. As intravenously administered enzyme cannot cross the blood-brain barrier, the therapy of choice for the more severe Hurler syndrome is haematopoietic stem cell transplantation (HCT). In the more attenuated Scheie syndrome, neurological impairment is less severe; therefore, ERT may be appropriate to treat these patients. Information on long-term outcome in Scheie patients undergoing ERT is scarce. We report a 38-year-old female Scheie patient who has been on ERT for 8 years. While non-neurological symptoms improved, she developed paresthesias in her hands and feet and progressive pain in her legs. Somatosensory evoked potentials were abnormal, suggesting dysfunction of the dorsal funiculus and lemniscus medialis. After 6 years of ERT, a spinal MRI showed dural thickening at the upper cervical spine. These soft-tissue deposits are presumably due to the accumulation of mucopolysaccharides. Intramedullary hyperintensities at the level of C1/2 revealed cervical myelopathy. An MRI before the start of ERT had shown milder spinal lesions. Cystic lesions in the white matter of the centrum semiovale due to dilated Virchow-Robin spaces were essentially unchanged compared with the MRI scan before ERT. Decompression of the spinal cord resulted in clinical improvement. In an adult patient with Scheie syndrome, ERT failed to prevent progression of cervical myelopathy. Clinical significance of cerebral changes is unclear. Whether early HCT or intrathecal ERT could have prevented these lesions remains speculative.

Phagocytosis and postphagocytic reaction of cord blood and adult blood monocyte after infection with green fluorescent protein-labeled Escherichia coli and group B Streptococci

BACKGROUND

Neonatal sepsis is characterized by an excessive inflammatory response induced by immune cells (monocytes). We investigated the initial stage of monocyte-pathogen interaction, i.e. bacterial ingestion and degradation at the single-cell level, by comparing a new flow cytometric procedure with culture methods. We also examined the hypothesis that, in terms of phagocytosis-induced cell death (PICD), phenotype, or cytokine production, cord blood monocytes (CBMO) differ from monocytes derived from adults (peripheral blood monocytes, PBMO).

METHODS

Phagocytosis and intracellular degradation were assessed by means of flow cytometry and bacterial cultures of green fluorescent protein-labeled group B Streptococci (GBS) and Escherichia coli. The production of reactive oxygen species (ROS) was measured through luminol-enhanced chemiluminescence. Apoptosis, phenotype, and cytokine production were assessed through flow cytometry.

RESULTS

Flow cytometry and bacterial cultures showed no difference between phagocytosis and degradation of GBS and E. coli by PBMO and CBMO. A high correlation between both methods was observed. No difference in ROS production was evident. In comparison with PBMO, CBMO apoptosis was lower after exposure to GBS and E. coli. Similarities were found between nonapoptotic monocytes and pro-inflammatory monocytes.

CONCLUSIONS

PICD is lower in CBMO during the early stages of monocyte-pathogen interaction. Our results emphasize that monocyte apoptosis has a potential role in tailoring the immune response in neonatal sepsis.

Glucose metabolism and liver cirrhosis

Chronic liver disease is characterized by numerous metabolic alterations, predominantly catabolic, resulting in the clinical picture of malnutrition and even cachexia in some patients. The following review focuses on disturbances of glucose metabolism and of hormonal interactions that could contribute to the clinical picture of malnutrition seen in chronic liver disease. Body composition is altered in a characteristic manner with an increase in fat mass and a significant loss of muscle tissue. Furthermore, defective glucose storage due to reduced insulin sensitivity predominantly of muscle tissue has been observed. The pathogenesis of insulin resistance leading to an impaired glucose tolerance or a manifest diabetes mellitus is as yet unknown. A receptor/postreceptor dysfunction probably exists in chronic liver disease that might be explained by the following factors: 1. Altered membrane lipid composition and increased levels of free fatty acids; 2. long-lasting hyperinsulinemia; 3. increased plasma levels of insulin counteracting hormones such as growth hormone, glucagon, catecholamines and possibly cytokines; 4. a lack of liver-derived humoral factors with insulin-like activity, i.e. insulin-like growth factors I and II.

Prenatal benzoate treatment in urea cycle defects

OBJECTIVE

In patients with severe urea cycle defects (UCD) metabolic decompensation with hyperammonaemia typically occurs during the first days of life resulting in severe neurological damage or death. Benzoate can eliminate nitrogen independent of the urea cycle. Usually, benzoate is started soon after birth, but prenatal administration might improve metabolic stability.

DESIGN

Two fetuses with a prenatal diagnosis of UCD (female: citrullinaemia; male: ornithine transcarbamylase deficiency) were loaded with benzoate prenatally via the placenta by infusing their mothers with benzoate. Benzoate concentrations were measured in umbilical cord blood and the blood of the mothers and their newborns.

RESULTS

Therapeutic concentrations of benzoate were found in umbilical cord blood and in the children's blood. Thus, benzoate transfer across the placenta was demonstrated. Plasma ammonia and glutamine levels in the postnatal period were within the normal range.

CONCLUSIONS

Benzoate infusion of the mother shortly before birth is safe and results in therapeutic levels of benzoate in umbilical cord blood.

Influence of different oral rehydration solutions on abomasal conditions and the acid-base status of suckling calves

The aim of the study was to investigate the influence of oral rehydration solutions (ORS) on milk clotting, abomasal pH, electrolyte concentrations, and osmolality, as well as on the acid-base status in blood of suckling calves, as treatment with ORS is the most common therapy of diarrhea in calves to correct dehydration and metabolic acidosis. Oral rehydration solutions are suspected to inhibit abomasal clotting of milk; however, it is recommended to continue feeding cow's milk or milk replacer (MR) to diarrheic calves to prevent body weight losses. Three calves with abomasal cannulas were fed MR, MR-ORS mixtures, or water-ORS mixtures, respectively. Samples of abomasal fluid were taken before and after feeding at various time points, and pH, electrolyte concentrations, and osmolality were measured. The interference of ORS with milk clotting was examined in vivo and in vitro. To evaluate the effects of ORS on systemic acid-base status, the Stewart variables strong ion difference ([SID]), acid total ([A(tot)]), and partial pressure of CO2 (pCO2) were quantified in venous blood samples drawn before and after feeding. Calves reached higher abomasal pH values when fed with MR-ORS mixtures than when fed MR. Preprandial pH values were re-established after 4 to 6 h. Oral rehydration solutions prepared in water increased the abomasal fluid pH only for 1 to 2 h. Oral rehydration solutions with high [SID(3)] ([Na(+)] + [K(+)] - [Cl(-)]) values produced significantly higher abomasal pH values and area under the curve data of the pH time course. Caseinomacropeptide, an indicator of successful enzymatic milk clotting, could be identified in every sample of abomasal fluid after feeding MR-ORS mixtures. The MR-ORS mixtures with [SID(3)] values > or =92 mmol/L increased serum [SID(3)] but did not change venous blood pH. Oral rehydration solutions do not interfere with milk clotting in the abomasum and can, therefore, be administered with milk. In this study, MR-ORS mixtures with high [SID(3)] values caused an increase of serum [SID(3)] in healthy suckling calves and may be an effective treatment for metabolic acidosis in calves suffering from diarrhea.

Diagnostische Bewertung der Stewart-Variablen des Säuren-Basen-Status bei klinisch gesunden und erkrankten Pferden mit Infusionstherapie

Gegenstand und Ziel: Vergleichende Beurteilung des Säuren-Basen-Status (SBS) mit dem Henderson- Hasselbalch-(HH-)-Modell und der Stewart-Variablen PCO2, [strong ion difference = SID] und [Acid total = Atot]. Material und Methoden: Im arteriellen und venösen Blut wurden von 38 klinisch gesunden Pferden Referenzwerte der Stewart-Variablen ermittelt. Ferner wurden bei zwei erkrankten Tieren in den vor, während und nach Infusionstherapie entnommenen Blutproben die SBS-Parameter bestimmt. Im venösen Blutserum erfolgte die Analyse der Elektrolyte und des Gesamtproteins inklusive seiner Fraktionen. Ergebnisse: Referenzbereiche (̄ ± 1,96⋅s) für die Stewart-Variablen von den klinisch gesunden Pferden: PvCO2 = 5,0–7,3 kPa, Serum-[SID3] = 38,5–45,1 mmol/l bzw. -[SID4] = 37,7–44,2 mmol/l, Serum-[Atot1] = 11,7–17,3 mmol/l bzw. -[Atot2] = 11,5–15,4 mmol/l. Der aus den Stewart-Variablen kalkulierte pH war 0,06 Einheiten alkalischer als der gemessene Blut-pH. Patient 1 (chronische respiratorische Erkrankung) wies vor Infusion keinen veränderten SBS auf. Während und nach Hyperinfusion von 30 l isotoner NaCl-Lösung binnen 3 h kam es im venösen Blut zu folgenden Reaktionen: ↓pH, ↓[HCO3 –], ↓[BE] (= HH-Parameter); ↓[SID3, 4] und ↓[Atot1, 2] (= Stewart-Parameter). Die post infusionem (p. i.) transiente milde Azidose des Pferdes erklärt sich aus den unphysiologisch niedrigen Stewart-Variablen der 0,9%igen NaCl-Lösung mit [SID3, 4] = 0 mmol/l und [Atot1, 2] = 0 mmol/l. Das kolikkranke Pferd (Fall 2) zeigte vor Infusionsbeginn im Blut →pH, ↓[HCO3 –], ↓[BE], ↓PCO2 und ↓[SID4], was eine metabolische Azidose mit respiratorischer Kompensation signalisiert. Die Infusion von 12 l Ringerlösung ([SID3, 4] = –4,5 mmol/l, [Atot1, 2] = 0 mmol/l) bewirkte 1 h p. i. den ↓[SID3, 4] (= azidotische Reaktion) und den ↓[Atot1, 2] (= basische Reaktion). Klinische Relevanz: Anhand der HH-Parameter lassen sich SBS-Störungen hinsichtlich Azidämie oder Alkalämie sowie respiratorisch verursachter Imbalancen eindeutig diagnostizieren. Für die bei Tieren häufigeren nichtrespiratorischen (= metabolischen) Azidosen bzw. Alkalosen leisten die Stewart-Variablen ([SID], [Atot]) wertvolle Hilfe bezüglich Ursachenaufklärung, wie Imbalancen der Elektrolyte oder Proteine, und ermöglichen so eine gezielte Auswahl von geeigneten Korrekturlösungen bei der Flüssigkeitstherapie.

Inclusive K(S);(0)K(S);(0) resonance production in ep collisions at HERA

Inclusive K_{S};{0}K_{S};{0} production in ep collisions at the DESY ep collider HERA was studied with the ZEUS detector using an integrated luminosity of 0.5 fb;{-1}. Enhancements in the mass spectrum were observed and are attributed to the production of f_{2}(1270)/a_{2};{0}(1320), f_{2};{'}(1525) and f_{0}(1710). Masses and widths were obtained using a fit which takes into account theoretical predictions based on SU(3) symmetry arguments, and are consistent with the Particle Data Group values. The f_{0}(1710) state, which has a mass consistent with a glueball candidate, was observed with a statistical significance of 5 standard deviations. However, if this state is the same as that seen in gammagamma-->K_{S};{0}K_{S};{0}, it is unlikely to be a pure glueball state.

Hypoxia-independent activation of HIF-1 by enterobacteriaceae and their siderophores

BACKGROUND & AIMS

Hypoxia inducible factor-1 (HIF-1) is the key transcriptional regulator during adaptation to hypoxia. Recent studies provide evidence for HIF-1 activation during bacterial infections. However, molecular details of how bacteria activate HIF-1 remain unclear. Here, we pursued the role of bacterial siderophores in HIF-1 activation during infection with Enterobacteriaceae.

METHODS

In vivo, HIF-1 activation and HIF-1-dependent gene induction in Peyer's patches were analyzed after orogastric infection with Yersinia enterocolitica. The course of an orogastric Y enterocolitica infection was determined using mice with a deletion of HIF-1alpha in the intestine. In vitro, the mechanism of HIF-1 activation was analyzed in infections with Y enterocolitica, Salmonella enterica subsp enterica, and Enterobacter aerogenes.

RESULTS

Infection of mice with Y enterocolitica led to functional activation of HIF-1 in Peyer's patches. Because mice with deletion of HIF-1alpha in the intestinal epithelium showed a significantly higher susceptibility to orogastric Y enterocolitica infections, bacterial HIF-1 activation appears to represent a host defense mechanism. Additional studies with Y enterocolitica, S enterica subsp enterica, or E aerogenes, and, moreover, application of their siderophores (yersiniabactin, salmochelin, aerobactin) caused a robust, dose-dependent HIF-1 response in human epithelia and endothelia, independent of cellular hypoxia. HIF-1 activation occurs most likely because of inhibition of prolylhydroxylase activity and is abolished upon infection with siderophore uptake deficient bacteria.

CONCLUSIONS

Taken together, this study reveals what we believe to be a previously unrecognized role of bacterial siderophores for hypoxia-independent activation of HIF-1 during infection with human pathogenic bacteria.