Vaccine-elicited CD4 T cells prevent the deletion of antiviral B cells in chronic infection.

Chronic viral infections subvert protective B cell immunity. An early type I interferon (IFN-I)-driven bias to short-lived plasmablast differentiation leads to clonal deletion, so-called "decimation," of antiviral memory B cells. Therefore, prophylactic countermeasures against decimation remain an unmet need. We show that vaccination-induced CD4 T cells prevented the decimation of naïve and memory B cells in chronically lymphocytic choriomeningitis virus (LCMV)-infected mice. Although these B cell responses were largely T independent when IFN-I was blocked, preexisting T help assured their sustainability under conditions of IFN-I-driven inflammation by instructing a germinal center B cell transcriptional program. Prevention of decimation depended on T cell-intrinsic Bcl6 and Tfh progeny formation. Antigen presentation by B cells, interactions with antigen-specific T helper cells, and costimulation by CD40 and ICOS were also required. Importantly, B cell-mediated virus control averted Th1-driven immunopathology in LCMV-challenged animals with preexisting CD4 T cell immunity. Our findings show that vaccination-induced Tfh cells represent a cornerstone of effective B cell immunity to chronic virus challenge, pointing the way toward more effective B cell-based vaccination against persistent viral diseases.

A Controlled Increase in Dietary Phosphate Elevates BP in Healthy Human Subjects.

Background Despite epidemiologic evidence for increased cardiovascular morbidity and mortality associated with both high dietary and serum phosphate in humans with normal renal function, no controlled phosphate intervention studies of systemic hemodynamics have been reported. Higher serum 25(OH) vitamin D levels are associated with better cardiovascular outcomes, but vitamin D increases intestinal phosphate absorption.Methods We conducted a prospective outpatient study with blinded assessment in 20 young adults with normal renal function randomized to high phosphate (regular diet plus 1 mmol/kg body wt per day of Na as neutral sodium phosphate) or low phosphate (regular diet plus lanthanum, 750 mg thrice/day, plus 0.7 mmol/kg body wt per day of Na as NaCl) for 11 weeks. After 6 weeks, all subjects received vitamin D3 (600,000 U) by intramuscular injection. Outcome parameters were 24-hour ambulatory systolic and diastolic BP (SBP and DBP), pulse rate (PR), biomarkers, and measures of endothelial and arterial function.Results Compared with the low-phosphate diet group, the high-phosphate diet group had a significant increase in mean±SEM fasting plasma phosphate concentration (0.23±0.11 mmol/L); 24-hour SBP and DBP (+4.1; 95% confidence interval [95% CI], 2.1 to 6.1; and +3.2; 95% CI, 1.2 to 5.2 mm Hg, respectively); mean 24-hour PR (+4.0; 95% CI, 2.0 to 6.0 beats/min); and urinary metanephrine and normetanephrine excretion (54; 95% CI, 50 to 70; and 122; 95% CI, 85 to 159 µg/24 hr, respectively). Vitamin D had no effect on any of these parameters. Neither high- nor low-phosphate diet nor vitamin D affected endothelial function or arterial elasticity.Conclusions Increased phosphate intake (controlled for sodium) significantly increases SBP, DBP, and PR in humans with normal renal function, in part, by increasing sympathoadrenergic activity.

T cell-dependence of Lassa fever pathogenesis.

Lassa virus (LASV), the causative agent of Lassa fever (LF), is endemic in West Africa, accounting for substantial morbidity and mortality. In spite of ongoing research efforts, LF pathogenesis and mechanisms of LASV immune control remain poorly understood. While normal laboratory mice are resistant to LASV, we report that mice expressing humanized instead of murine MHC class I (MHC-I) failed to control LASV infection and develop severe LF. Infection of MHC-I knockout mice confirmed a key role for MHC-I-restricted T cell responses in controlling LASV. Intriguingly we found that T cell depletion in LASV-infected HHD mice prevented disease, irrespective of high-level viremia. Widespread activation of monocyte/macrophage lineage cells, manifest through inducible NO synthase expression, and elevated IL-12p40 serum levels indicated a systemic inflammatory condition. The absence of extensive monocyte/macrophage activation in T cell-depleted mice suggested that T cell responses contribute to deleterious innate inflammatory reactions and LF pathogenesis. Our observations in mice indicate a dual role for T cells, not only protecting from LASV, but also enhancing LF pathogenesis. The possibility of T cell-driven enhancement and immunopathogenesis should be given consideration in future LF vaccine development.

Remote ischemic preconditioning applied during isoflurane inhalation provides no benefit to the myocardium of patients undergoing on-pump coronary artery bypass graft surgery: lack of synergy or evidence of antagonism in cardioprotection?

BACKGROUND: Two preconditioning stimuli should induce a more consistent overall cell protection. We hypothesized that remote ischemic preconditioning (RIPC, second preconditioning stimulus) applied during isoflurane inhalation (first preconditioning stimulus) would provide more protection to the myocardium of patients undergoing on-pump coronary artery bypass grafting. METHODS: In this placebo-controlled randomized controlled study, patients in the RIPC group received four 5-min cycles of 300 mmHg cuff inflation/deflation of the leg before aortic cross-clamping. Anesthesia consisted of opioids and propofol for induction and isoflurane for maintenance. The primary outcome was high-sensitivity cardiac troponin T release. Secondary endpoints were plasma levels of N-terminal pro-brain natriuretic peptide, high-sensitivity C-reactive protein, S100 protein, and short- and long-term clinical outcomes. Gene expression profiles were obtained from atrial tissue using microarrays. RESULTS: RIPC (n = 27) did not reduce high-sensitivity cardiac troponin T release when compared with placebo (n = 28). Likewise, N-terminal pro-brain natriuretic peptide, a marker of myocardial dysfunction; high-sensitivity C-reactive protein, a marker of perioperative inflammatory response; and S100, a marker of cerebral injury, were not different between the groups. The incidence for the perioperative composite endpoint combining new arrhythmias and myocardial infarctions was higher in the RIPC group than the placebo group (14/27 vs. 6/28, P = 0.036). However, there was no difference in the 6-month cardiovascular outcome. N-terminal pro-brain natriuretic peptide release correlated with isoflurane-induced transcriptional changes in fatty-acid metabolism (P = 0.001) and DNA-damage signaling (P < 0.001), but not with RIPC-induced changes in gene expression. CONCLUSIONS: RIPC applied during isoflurane inhalation provides no benefit to the myocardium of patients undergoing on-pump coronary artery bypass grafting.

Gut microbiome and circulating bacterial DNA ("blood microbiome") in a mouse model of total parenteral nutrition: Evidence of two distinct separate microbiotic compartments.

BACKGROUND & AIMS: Total parenteral nutrition (TPN) causes gut atrophy, dysbiosis and leakage of the gut barrier. This study aimed to characterize the gut microbiome in response to different TPNs and tested the hypothesis whether increased gut permeability in TPN would lead to changes in the circulating bacterial DNA ("blood microbiome"). METHODS: Male C57BL/6J mice were randomly allocated to the following groups for seven days (1) chow-fed control (C) without jugular vein catheter (JVC, n=6) (2) chow-fed with JVC and infusion of saline (S) (n = 6) (3) Intralipid-based TPN (n-6:n-3 ratio 7:1) (IL, n = 6) (4) Omegaven-based TPN (n-6:n-3 ratio 1:8) (OV, n = 6). Blood was collected by cardiac puncture and feces (stool pellet) were collected from the colon. Blood and stool samples were analyzed by 16S rRNA gene sequencing. RESULTS: TPN administration was associated with a compositional shift in the gut microbial community that involved the expansion of Bacteroidota along with a decrease in gut bacteria belonging to the Firmicutes phylum as compared to chow-fed mice. Gram-negative Verrucomicrobiota and Proteobacteria were also increased in the gut microbiome of mice receiving TPN. Gammaproteobacteria, namely Burkholderiales, were specifically increased in Intralipid-based TPN. On the other hand, Proteobacteria and Actinobacteriota were the dominant taxa in blood samples. The families Comamonadaceae and Burkholderiaceae (both from Burkholderiales order) were increased in the "blood microbiome" of mice with indwelling JVC when compared with chow-fed mice without JVC. The increase in Burkholderiaceae was more pronounced in Intralipid-based TPN. CONCLUSIONS: Profound changes in the gut microbiome of mice subjected to TPN occurred, which were not reflected in the "blood microbiome" suggesting that the gut and "blood microbiome" represent two rather distinct separate microbiotic compartments. The parenteral provision of n-3 fatty acids appears to protect against proinflammatory bacteria in the gut and against the increased presence of JVC-associated bacteria as measured by circulating bacterial DNA.

Effects of thyroxine replacement on serum creatinine and cystatin C in patients with primary and central hypothyroidism.

BACKGROUND: Serum cystatin C (CysC) is a marker for kidney function, possibly superior to serum creatinine (Cr). Cr is increased and CysC decreased in primary hypothyroidism; these changes are reversed upon thyroxine (T4) replacement therapy. This (pilot) study was performed to see whether these opposing changes of CysC and Cr could be confirmed in patients with central hypothyroidism. METHODS: Prospective case series of consecutively referred patients with primary and central hypothyroidism. CysC and Cr were determined at the time of diagnosis and following T4 replacement therapy. RESULTS: 32 patients with newly diagnosed hypothyroidism were included. In 16 patients with primary hypothyroidism, mean fT4 was 4.4 +/- 2.5 pmol/l (normal range 12 to 22) at diagnosis and increased to 20.1 +/- 5.2 pmol/l (p <0.001) following T4 replacement. CysC increased from 0.79 +/- 0.27 mg/l (normal range 0.63 to 1.33) to 1.03 +/- 0.42 mg/l (p = 0.007) whereas Cr declined from 104 +/- 21 micromol/l to 90 +/- 19 micromol/l (p <0.001). In 16 patients with central hypothyroidism, mean fT4 was 6.5 +/- 1.6 pmol/l at diagnosis and increased to 15.7 +/- 3.3 pmol/l (p <0.001) following T4 replacement. CysC increased from 0.74 +/- 0.27 mg/l to 0.83 +/- 0.30 mg/l (p = 0.01) whereas Cr was not elevated at baseline (83 +/- 11 micromol/l) and did not decrease following treatment (84 +/- 10 micromol/l). CONCLUSIONS: CysC was low at diagnosis of hypothyroidism and significantly increased following T4 replacement in patients with primary as well as central hypothyroidism. T4 replacement decreased Cr levels in patients with primary hypothyroidism whereas Cr remained unchanged in;patients with central hypothyroidism. CysC may not accurately reflect kidney function in patients with primary and central thyroid dysfunction.

Hyponatremia among runners in the Zurich Marathon.

OBJECTIVE: Hyperhydration and exercise-associated hyponatremia (EAH) are critical issues during endurance events. We studied a cohort of marathon runners to examine EAH's prevalence in a marathon with a short time limit and to investigate underlying mechanisms that may be responsible for its development. DESIGN: Observational cohort study. SETTING: 2006 Zurich Marathon (cool and rainy weather, time limit of 5 hours). PARTICIPANTS: 167 marathon runners were recruited the month before the race. MAIN OUTCOME MEASURES: Body mass, plasma sodium, and osmolality were measured just before the start and immediately after the race. Fluid intake during the race was ascertained by a recall questionnaire. RESULTS: Five subjects (3 %) developed asymptomatic EAH, and no symptomatic EAH was found. Body mass change during the race correlated similarly with postrace sodium levels (r = -0.72, P < 0.0001) and with sodium change during the race (r = -0.66, P < 0.0001). Postrace sodium levels correlated significantly with sodium change during the race (r = 0.74, P < 0.0001). Fluid intake correlated significantly (r = -0.43, P < 0.0001) with plasma sodium change between the start and finish of the race. Postrace sodium levels and postrace osmolality were significantly correlated (r = 0.68, P < 0.0001). CONCLUSION: In this study we observed a relatively low incidence of EAH in subjects running the marathon in around 2.5 to 5 hours and in a cool environment. Plasma sodium change during the race and postrace sodium levels correlated with body mass change. There was also a direct correlation between fluid intake and plasma sodium change during the race.

Interferon-γ-Driven iNOS: A Molecular Pathway to Terminal Shock in Arenavirus Hemorrhagic Fever.

Arenaviruses such as Lassa virus (LASV) cause hemorrhagic fever. Terminal shock is associated with a systemic cytokine storm, but the mechanisms are ill defined. Here we used HLA-A2-expressing mice infected with a monkey-pathogenic strain of lymphocytic choriomeningitis virus (LCMV-WE), a close relative of LASV, to investigate the pathophysiology of arenavirus hemorrhagic fever (AHF). AHF manifested as pleural effusions, edematous skin swelling, and serum albumin loss, culminating in hypovolemic shock. A characteristic cytokine storm included numerous pro-inflammatory cytokines and nitric oxide (NO) metabolites. Edema formation and terminal shock were abrogated in mice lacking inducible nitric oxide synthase (iNOS), although the cytokine storm persisted. iNOS was upregulated in the liver in a T cell- and interferon-γ (IFN-γ)-dependent fashion. Accordingly, blockade of IFN-γ or depletion of T cells repressed hepatic iNOS and prevented disease despite unchecked high-level viremia. We identify the IFN-γ-iNOS axis as an essential and potentially druggable molecular pathway to AHF-induced shock.

Genetic polymorphisms of apolipoprotein E4 and tumor necrosis factor beta as predisposing factors for increased inflammatory cytokines after cardiopulmonary bypass.

OBJECTIVE: Cardiopulmonary bypass induces a rise in cytokines released by activated monocytes. The apolipoprotein E and the tumor necrosis factor beta polymorphisms are risk factors for atherosclerosis. The aim of the study was to investigate whether the genetic variants of apolipoprotein E (APOE*E4) and tumor necrosis factor beta (TNFB*A329G) affect cytokine release after cardiopulmonary bypass. METHODS: Thirty-eight patients underwent standard coronary artery bypass grafting procedures. Genotyping for APOE*E4 and TNFB*A329G was performed. Concentrations of interleukin 8 and tumor necrosis factor alpha were measured for 48 hours after surgery. Clinical data were collected prospectively. RESULTS: Fourteen patients (37%) carried the combination non-APOE*E4/wild-type TNFB*A329, 12 patients (32%) showed non-APOE*E4/TNFB*A329G, 9 patients (24%) had APOE*E4/TNFB*A329G, and 3 patients (7%) had APOE*E4/wild-type TNFB*A329. Total amount of tumor necrosis factor alpha was significantly higher in patients carrying the combination APOE*E4/TNFB*A329 than in those carrying non-APOE*E4/wild-type TNFB*A329 (P <.0001). Clinical data were similar except for intubation time and amount of transfusion, which were significantly increased in patients with genetic polymorphisms (P =.022, P =.033). CONCLUSION: Presence of TNFB*A329G polymorphism in addition to APOE*E4 variant is associated with significantly higher releases of interleukin 8 and tumor necrosis factor alpha, prolonged intubation, and increased transfusion relative to patients without genetic variants. Preoperative determination of APOE/TNFB genotypes in patients undergoing coronary artery bypass grafting may lead to additional perioperative measures to ameliorate systemic inflammatory response.

Osteoblasts response to allogenic and xenogenic solvent dehydrated cancellous bone in vitro.

The present in vitro study investigates the cellular interaction of primary human osteoblasts with human and bovine solvent dehydrated cancellous bone (SDCB) discs. These are bio-implants from solvent dehydrated, gamma-irradiated preserved human and bovine cancellous bone, pre-treated to remove all cells, genetic components and water soluble proteins. Primary human osteoblasts were harvested from cancellous chips of trauma patients undergoing osteosynthesis with bone grafting from the iliac crest. All patients provided informed consent. The present investigation tested proliferation, synthesis of phenotypic marker, and morphology of primary cultured human osteoblasts on SDCB in vitro. The total protein and collagen type 1 content could not be revealed, due to the inherent naturally occurring protein content in these two bio-implants. In conclusion, our in vitro results suggest that SDCB may be a suitable bone substitute which provides a well structured and biocompatible scaffold for ingrowing human osteoblasts.

High Prevalence of Iron Deficiency among Educated Hospital Employees in Switzerland.

Iron deficiency is known to cause symptoms such as fatigue, depression and restless legs syndrome resulting in impaired quality of life and working capacity. We sought to examine the iron status of reportedly healthy individuals by a framed study design in 58 highly educated Swiss hospital employees and to compare the use of non invasive tests for assessing iron deficiency (ID). A structured interview was used to assess health status, nutritional intake and potential blood loss, blood counts as well as parameters proposed to diagnose iron deficiency were determined. All subjects felt well and were working at their maximum capacity. The male subjects were neither anaemic nor had decreased iron parameters however 50% (23/46) of the women had a serum ferritin of below 22 µg/L, still 33% (15/46) of the women had a ferritin value below the more stringent cut off value of 15 µg/L. In 15% (7/46) of the women we diagnosed iron deficient anaemia. Red meat consumption correlated with ferritin values as did the menstrual blood loss which was estimated by asking the amount of tampons used. Of the additionally analysed iron parameters only the percentage of hypochromic erythrocytes, soluble transferrin receptor and transferrin values were significantly correlated with ferritin and reached an AUCROC of ≥0.7 indicating good predictive tests. Nevertheless neither soluble transferrin receptor nor transferrin showed diagnostic advantages for the diagnosis of ID compared to ferritin alone or together with erythrocyte parameters. Working in a hospital environment and having access to health education does not seem to correlate with prevention of ID or ID anaemia in female hospital employees.

Automated urinalysis: first experiences and a comparison between the Iris iQ200 urine microscopy system, the Sysmex UF-100 flow cytometer and manual microscopic particle counting.

BACKGROUND: Automated analysis of insoluble urine components can reduce the workload of conventional microscopic examination of urine sediment and is possibly helpful for standardization. We compared the diagnostic performance of two automated urine sediment analyzers and combined dipstick/automated urine analysis with that of the traditional dipstick/microscopy algorithm. METHODS: A total of 332 specimens were collected and analyzed for insoluble urine components by microscopy and automated analyzers, namely the Iris iQ200 (Iris Diagnostics) and the UF-100 flow cytometer (Sysmex). RESULTS: The coefficients of variation for day-to-day quality control of the iQ200 and UF-100 analyzers were 6.5% and 5.5%, respectively, for red blood cells. We reached accuracy ranging from 68% (bacteria) to 97% (yeast) for the iQ200 and from 42% (bacteria) to 93% (yeast) for the UF-100. The combination of dipstick and automated urine sediment analysis increased the sensitivity of screening to approximately 98%. CONCLUSIONS: We conclude that automated urine sediment analysis is sufficiently precise and improves the workflow in a routine laboratory. In addition, it allows sediment analysis of all urine samples and thereby helps to detect pathological samples that would have been missed in the conventional two-step procedure according to the European guidelines. Although it is not a substitute for microscopic sediment examination, it can, when combined with dipstick testing, reduce the number of specimens submitted to microscopy. Visual microscopy is still required for some samples, namely, dysmorphic erythrocytes, yeasts, Trichomonas, oval fat bodies, differentiation of casts and certain crystals.

Contributions of the lymphocytic choriomeningitis virus glycoprotein and polymerase to strain-specific differences in murine liver pathogenicity.

Hepatic involvement is commonly observed in arenavirus infections, but the viral determinants of liver disease are only partially understood. Here we exploited newly developed reverse-genetic techniques with Lymphocytic choriomeningitis virus (LCMV), the prototype arenavirus, to address specifically the contribution of the viral glycoprotein (GP) to liver pathogenicity. It is well established that strain WE, but not ARM, causes hepatitis in mice. We found that this property correlated with the superior capacity of WE to propagate in cultured macrophages and hepatocyte-derived cells. In mice, the ability to establish prolonged viraemia allowed the virus to propagate from initially infected Kupffer cells in the liver to neighbouring hepatocytes that underwent apoptosis. Reverse-genetic replacement of the GP in strain ARM with WE-GP resulted in only a very modest increase in liver pathogenicity, if any. Yet, an ARM-derived variant virus with a mutated polymerase gene caused severe liver disease when engineered to display WE-GP but considerably less when expressing ARM-GP. This reverse-genetic approach to an animal model of arenaviral hepatitis reveals a previously underestimated contributory role of the GP that alone is, however, insufficient to cause disease.

Gene regulatory control of myocardial energy metabolism predicts postoperative cardiac function in patients undergoing off-pump coronary artery bypass graft surgery: inhalational versus intravenous anesthetics.

BACKGROUND: Anesthetic gases modulate gene expression and provide organ protection. This study aimed at identifying myocardial transcriptional phenotypes to predict cardiovascular biomarkers and function in patients undergoing off-pump coronary artery bypass graft surgery. METHODS: In a prospective randomized trial, patients undergoing elective off-pump coronary artery bypass graft surgery were allocated to receive either the anesthetic gas sevoflurane (n = 10) or the intravenous anesthetic propofol (n = 10). Blood samples were collected perioperatively to determine cardiac troponin T, N-terminal pro-brain natriuretic peptide, and pregnancy-associated plasma protein A. Cardiac function was measured with transesophageal echocardiography and pulmonary artery thermodilution. Atrial biopsies were collected at the beginning and end of bypass surgery to determine gene expression profiles. RESULTS: N-terminal pro-brain natriuretic peptide and pregnancy-associated plasma protein A blood levels were decreased with sevoflurane treatment. Echocardiography showed preserved postoperative cardiac function in sevoflurane patients, which paralleled higher cardiac index measurements. N-terminal pro-brain natriuretic peptide release was predicted by sevoflurane-induced transcriptional reduction in fatty acid oxidation, whereas changes in cardiac index were predicted by preoperative gene activity of the peroxisome proliferator-activated receptor gamma coactivator-1alpha pathway. Sevoflurane-mediated attenuation of transcripts involved in DNA-damage signaling and activation of the granulocyte colony-stimulating factor survival pathway predicted improved postoperative cardiac index and diastolic heart function, respectively. CONCLUSIONS: Anesthetic-induced and constitutive gene regulatory control of myocardial substrate metabolism predicts postoperative cardiac function in patients undergoing off-pump coronary artery bypass graft surgery. The authors' analysis further points to novel cardiac survival pathways as potential therapeutic targets in perioperative cardioprotection.

Adrenergic receptor genotype but not perioperative bisoprolol therapy may determine cardiovascular outcome in at-risk patients undergoing surgery with spinal block: the Swiss Beta Blocker in Spinal Anesthesia (BBSA) study: a double-blinded, placebo-controlled, multicenter trial with 1-year follow-up.

BACKGROUND: Neuraxial blockade is used as primary anesthetic technique in one third of surgical procedures. The authors tested whether bisoprolol would protect patients at risk for cardiovascular complications undergoing surgery with spinal block. METHODS: The authors performed a double-blinded, placebo-controlled, multicenter trial to compare the effect of bisoprolol with that of placebo on 1-yr composite outcome including cardiovascular mortality, nonfatal myocardial infarction, unstable angina, congestive heart failure, and cerebrovascular insult. Bisoprolol was given orally before and after surgery for a maximum of 10 days. Adrenergic receptor polymorphisms and safety outcome measures of bisoprolol therapy were also determined. RESULTS: A total of 224 patients were enrolled. Spinal block could not be established in 5 patients. One hundred ten patients were assigned to the bisoprolol group, and 109 patients were assigned to the placebo group. The mean duration of treatment was 4.9 days in the bisoprolol group and 5.1 days in the placebo group. Bisoprolol therapy reduced mean heart rate by 10 beats/min. The primary outcome was identical between treatment groups and occurred in 25 patients (22.7%) in the bisoprolol group and 24 patients (22.0%) in the placebo group during the 1-yr follow-up (hazard ratio, 0.97; 95% confidence interval, 0.55-1.69; P = 0.90). However, carriers of at least one Gly allele of the beta1-adrenergic receptor polymorphism Arg389Gly showed a higher number of adverse events than Arg homozygous (32.4% vs. 18.7%; hazard ratio, 1.87; 95% confidence interval, 1.04-3.35; P = 0.04). CONCLUSIONS: Perioperative bisoprolol therapy did not affect cardiovascular outcome in these elderly at-risk patients undergoing surgery with spinal block.

Infarct-remodeled myocardium is receptive to protection by isoflurane postconditioning: role of protein kinase B/Akt signaling.

BACKGROUND: Postinfarct remodeled myocardium exhibits numerous structural and biochemical alterations. So far, it is unknown whether postconditioning elicited by volatile anesthetics can also provide protection in the remodeled myocardium. METHODS: Myocardial infarct was induced in male Wistar rats by ligation of the left anterior descending coronary artery. Six weeks later, hearts were buffer-perfused and exposed to 40 min of ischemia followed by 90 min of reperfusion. Anesthetic postconditioning was induced by 15 min of 2.1 vol% isoflurane. In some experiments, LY294002 (15 microM), a phosphatidylinositol 3-kinase inhibitor, was coadministered with isoflurane. Masson's trichrome staining, immunohistochemistry, Western blot analysis, and reverse-transcription polymerase chain reaction served to confirm remodeling. In buffer-perfused hearts, functional recovery was recorded, and acute infarct size was measured using 1% triphenyltetrazolium chloride staining and lactate dehydrogenase release during reperfusion. Western blot analysis was used to determine phosphorylation of reperfusion injury salvage kinases including protein kinase B/Akt and its downstream targets after 15 min of reperfusion. RESULTS: Infarct hearts exhibited typical macroscopic and molecular changes of remodeling. Isoflurane postconditioning improved functional recovery and decreased acute infarct size, as determined by triphenyltetrazolium (35 +/- 5% in unprotected hearts vs. 8 +/- 3% in anesthetic postconditioning; P < 0.05) and lactate dehydrogenase release. This protection was abolished by LY294002, which inhibited phosphorylation of protein kinase B/Akt and its downstream targets glycogen synthase kinase 3beta, endothelial nitric oxide synthase, and p70S6 kinase. CONCLUSIONS: Infarct-remodeled myocardium is receptive to protection by isoflurane postconditioning via protein kinase B/Akt signaling. This is the first time to demonstrate that anesthetic postconditioning retains its marked protection in diseased myocardium.

Influence of brain injury on early posttraumatic bone metabolism.

BACKGROUND: Various clinical studies and observations demonstrate enhanced osteogenesis in patients sustaining traumatic brain injury. It is presumed that the induction of this process starts early after trauma. The purpose of our study was to investigate humoral markers of bone metabolism during the early posttraumatic period, with special regard to traumatic brain injury. METHODS: Serum concentrations of biochemical markers of bone metabolism (calcium, inorganic phosphorus, carboxyl-terminal propeptide of type 1 procollagen, pyridinoline cross-linked telopeptide domain of type 1 collagen, Ostase, osteocalcin, intact parathyroid hormone, and calcitonin) were measured in three different groups of 80 patients during the first posttraumatic week. Patients were categorized into three groups: group I, fractures only; group II, isolated traumatic brain injury; and group III, traumatic brain injury in combination with fractures. RESULTS: Osteocalcin levels were significantly lower in the presence of traumatic brain injury (p < .05). Elevated pyridinoline cross-linked telopeptide domain of type 1 collagen levels expressed enhanced bone resorption in all groups, but levels were significantly higher in the absence of traumatic brain injury (p < .05). Intact parathyroid hormone levels were significantly higher on days 0 and 1 in the combined presence of traumatic brain injury plus fractures. CONCLUSION: These results demonstrate an imbalance of bone formation and resorption parameters in patients with traumatic brain injury during the early posttraumatic period, suggesting a central regulation in bone formation. The lower levels of osteocalcin detected in this study may play an important role in patients with brain injury and the later development of posttraumatic heterotopic ossification.

Preconditioning by sevoflurane decreases biochemical markers for myocardial and renal dysfunction in coronary artery bypass graft surgery: a double-blinded, placebo-controlled, multicenter study.

BACKGROUND: Preconditioning by volatile anesthetics is a promising therapeutic strategy to render myocardial tissue resistant to perioperative ischemia. It was hypothesized that sevoflurane preconditioning would decrease postoperative release of brain natriuretic peptide, a biochemical marker for myocardial dysfunction. In addition, several variables associated with the protective effects of preconditioning were evaluated. METHODS: Seventy-two patients scheduled for coronary artery bypass graft surgery under cardioplegic arrest were randomly assigned to preconditioning during the first 10 min of complete cardiopulmonary bypass with either placebo (oxygen-air mixture only) or sevoflurane 4 vol% (2 minimum alveolar concentration). No other volatile anesthetics were administered at any time during the study. Treatment was strictly blinded to anesthesiologists, perfusionists, and surgeons. Biochemical markers of myocardial dysfunction and injury (brain natriuretic peptide, creatine kinase-MB activity, and cardiac troponin T), and renal dysfunction (cystatin C) were determined. Results of Holter electrocardiography were recorded perioperatively. Translocation of protein kinase C was assessed by immunohistochemical analysis of atrial samples. RESULTS: Sevoflurane preconditioning significantly decreased postoperative release of brain natriuretic peptide, a sensitive biochemical marker of myocardial contractile dysfunction. Pronounced protein kinase C delta and epsilon translocation was observed in sevoflurane-preconditioned myocardium. In addition, postoperative plasma cystatin C concentrations increased significantly less in sevoflurane-preconditioned patients. No differences between groups were found for perioperative ST-segment changes, arrhythmias, or creatine kinase-MB and cardiac troponin T release. CONCLUSIONS: Sevoflurane preconditioning preserves myocardial and renal function as assessed by biochemical markers in patients undergoing coronary artery bypass graft surgery under cardioplegic arrest. This study demonstrated for the first time translocation of protein kinase C isoforms delta and epsilon in human myocardium in response to sevoflurane.