The gelatinases, MMP-2 and MMP-9, as fine tuners of neuroinflammatory processes.

This review focuses on the complementary roles of MMP-2 and MMP-9 in leukocyte migration into the brain in neuroinflammation, studied mainly in a murine model of experimental autoimmune encephalomyelitis (EAE) that has similarity to the human disease multiple sclerosis. We discuss the cellular sources of MMP-2/MMP-9 in EAE, their sites of activity, and how cleavage of the to-date identified MMP-2/MMP-9 substrates at the blood-brain barrier facilitate leukocyte filtration of the central nervous system (CNS). Where necessary, comparisons are made to inflammatory processes in the periphery and to other MMPs relevant to neuroinflammation. While the general principles concerning MMP-2 and MMP-9 function discussed here are relevant to all inflammatory situations, the details regarding substrates and molecular mechanisms of action are likely to be specific for neuroinflammation.

Collaborative meta-analysis finds no evidence of a strong interaction between stress and 5-HTTLPR genotype contributing to the development of depression.

The hypothesis that the S allele of the 5-HTTLPR serotonin transporter promoter region is associated with increased risk of depression, but only in individuals exposed to stressful situations, has generated much interest, research and controversy since first proposed in 2003. Multiple meta-analyses combining results from heterogeneous analyses have not settled the issue. To determine the magnitude of the interaction and the conditions under which it might be observed, we performed new analyses on 31 data sets containing 38 802 European ancestry subjects genotyped for 5-HTTLPR and assessed for depression and childhood maltreatment or other stressful life events, and meta-analysed the results. Analyses targeted two stressors (narrow, broad) and two depression outcomes (current, lifetime). All groups that published on this topic prior to the initiation of our study and met the assessment and sample size criteria were invited to participate. Additional groups, identified by consortium members or self-identified in response to our protocol (published prior to the start of analysis) with qualifying unpublished data, were also invited to participate. A uniform data analysis script implementing the protocol was executed by each of the consortium members. Our findings do not support the interaction hypothesis. We found no subgroups or variable definitions for which an interaction between stress and 5-HTTLPR genotype was statistically significant. In contrast, our findings for the main effects of life stressors (strong risk factor) and 5-HTTLPR genotype (no impact on risk) are strikingly consistent across our contributing studies, the original study reporting the interaction and subsequent meta-analyses. Our conclusion is that if an interaction exists in which the S allele of 5-HTTLPR increases risk of depression only in stressed individuals, then it is not broadly generalisable, but must be of modest effect size and only observable in limited situations.

Impulsiveness mediates the association between GABRA2 SNPs and lifetime alcohol problems.

Genetic variants in GABRA2 have previously been shown to be associated with alcohol measures, electroencephalography (EEG) ß waves and impulsiveness-related traits. Impulsiveness is a behavioral risk factor for alcohol and other substance abuse. Here, we tested association between 11 variants in GABRA2 with NEO-impulsiveness and problem drinking. Our sample of 295 unrelated adult subjects was from a community of families with at least one male with DSM-IV alcohol use diagnosis, and from a socioeconomically comparable control group. Ten GABRA2 SNPs (single-nucleotide polymorphisms) were associated with the NEO-impulsiveness (P < 0.03). The alleles associated with higher impulsiveness correspond to the minor alleles identified in previous alcohol dependence studies. All ten SNPs are in linkage disequilibrium (LD) with each other and represent one effect on impulsiveness. Four SNPs and the corresponding haplotype from intron 3 to intron 4 were also associated with Lifetime Alcohol Problems Score (LAPS, P < 0.03) (not corrected for multiple testing). Impulsiveness partially mediates (22.6% average) this relation between GABRA2 and LAPS. Our results suggest that GABRA2 variation in the region between introns 3 and 4 is associated with impulsiveness and this effect partially influences the development of alcohol problems, but a direct effect of GABRA2 on problem drinking remains. A potential functional SNP rs279827, located next to a splice site, is located in the most significant region for both impulsiveness and LAPS. The high degree of LD among nine of these SNPs and the conditional analyses we have performed suggest that all variants represent one signal.

High molecular weight hydroxyethyl starch solutions are not more effective than a low wmolecular weight hydroxyethyl starch solution in a porcine model of septic shock.

BACKGROUND: There is evidence that suggests that early fluid resuscitation is beneficial in the treatment of sepsis. We previously demonstrated that hydroxyethyl starch (HES) 130/0.42 attenuated capillary leakage better than HES 200/0.5. Using a similar porcine fecal sepsis model, we tested the effects of two new synthetic high molecular weight (700 kDa) hydroxyethyl starches with the same molar substitution of 0.42 but with a different C2/C6 ratio compared to 6% HES 130/0.42 on plasma volume (PV), systemic and tissue oxygenation. METHODS: This was a prospective, randomized, controlled animal study. Twenty-five anesthetized and mechanically ventilated pigs (28.4±2.3 kg) were observed over 8 h. Septic shock was induced with fecal peritonitis. Animals were randomized for volume-replacement therapy with HES 700/0.42 C2/C6/2.5:1 (N.=5), HES 700/0.42 C2/C6/6:1 (N.=5), HES 130/0.42 C2/C6/5:1 (N.=5) or Ringer's Solution (RS, N.=5), and compared to non-septic controls receiving RS (N.=5). The albumin escape rate (AER) was calculated and plasma volume was determined at the end of the study. Tissue Oxygen Saturation was measured with the InSpectra™ Device (InSpectra Tissue Spectrometer, Hutchinson Technology Inc., Hutchinson, MN, USA). RESULTS: The AER increased in all groups compared to control. All colloids (HES 700/6:1 68±15; HES 130 67±4; HES 700/2.5:1 71±12; P<0.05) but not RS (44±7) stabilized PV (mL/kg BW) after eight hours of sepsis. Systemic oxygenation was significantly lower in the RS group (44±17%; P<0.05) compared to all other groups at study end (P<0.05). CONCLUSION: In this porcine fecal peritonitis model, the high molecular weight artificial colloids HES 700/2.5:1 and HES 700/6:1 were not more effective in maintaining plasma volume and systemic and tissue oxygenation than HES 130. In comparison to crystalloid RS, all HES solutions were more effective at maintaining plasma volume, mean arterial pressure (MAP), and systemic and tissue oxygenation.

Regulation of glucose kinetics during exercise by the glucagon-like peptide-1 receptor.

In response to oral glucose, glucagon-like peptide-1 receptor (Glp1r) knockout (Glp1r−/−) mice become hyperglycaemic due to impaired insulin secretion. Exercise also induces hyperglycaemia in Glp1r−/− mice. In contrast to oral glucose, exercise decreases insulin secretion. This implies that exercise-induced hyperglycaemia in Glp1r−/− mice results from the loss of a non-insulinotropic effect mediated by the Glp1r. Muscle glucose uptake (MGU) is normal in exercising Glp1r−/− mice. Thus, we hypothesize that exercise-induced hyperglycaemia in Glp1r−/− mice is due to excessive hepatic glucose production (HGP). Wild-type (Glp1r+/+) and Glp1r−/− mice implanted with venous and arterial catheters underwent treadmill exercise or remained sedentary for 30 min. [3-3H]glucose was used to estimate rates of glucose appearance (Ra), an index of HGP, and disappearance (Rd). 2[14C]deoxyglucose was used to assess MGU. Glp1r−/− mice displayed exercise-induced hyperglycaemia due to an excessive increase in Ra but normal Rd and MGU. Exercise-induced glucagon levels were ∼2-fold higher in Glp1r−/− mice, resulting in a ∼2-fold higher glucagon:insulin ratio. Since inhibition of the central Glp1r stimulates HGP, we tested whether intracerebroventricular (ICV) infusion of the Glp1r antagonist exendin(9­39) (Ex9) in Glp1r+/+ mice would result in exercise-induced hyperglycaemia. ICV Ex9 did not enhance glucose levels or HGP during exercise, suggesting that glucoregulatory effects of Glp1 during exercise are mediated via the pancreatic Glp1r. In conclusion, functional disruption of the Glp1r results in exercise-induced hyperglycaemia associated with an excessive increase in glucagon secretion and HGP. These results suggest an essential role for basal Glp1r signalling in the suppression of alpha cell secretion during exercise.

Impulsiveness and insula activation during reward anticipation are associated with genetic variants in GABRA2 in a family sample enriched for alcoholism.

Genetic factors, externalizing personality traits such as impulsivity, and brain processing of salient stimuli all can affect individual risk for alcoholism. One of very few confirmed genetic association findings differentiating alcoholics from non-alcoholics is with variants in the inhibitory γ-amino butyric acid α2 receptor subunit (GABRA2) gene. Here we report the association of two of these GABRA2 variants with measures of alcohol symptoms, impulsivity and with insula cortex activation during anticipation of reward or loss using functional magnetic resonance imaging (fMRI). In a sample of 173 families (449 subjects), 129 of whom had at least one member diagnosed with alcohol dependence or abuse, carriers for the G allele in two single-nucleotide polymorphisms (SNPs) and haplotypes were more likely to have alcohol dependence symptoms (rs279858, P=0.01; rs279826, P=0.05; haplotype, P=0.02) and higher NEO Personality Inventory-Revised (NEO-PI-R) Impulsiveness scores (rs279858, P=0.016; rs279826, P=0.012; haplotype, P=0.032) with a stronger effect in women (rs279858, P=0.011; rs279826, P=0.002; haplotype, P=0.006), all P-values are corrected for family history and age. A subset of offspring from these families (n=44, 20 females), genotyped for GABRA2, participated in an fMRI study using a monetary incentive delay task. Increased insula activation during reward (r(2)=0.4; P=0.026) and loss (r(2)=0.38; P=0.039) anticipation was correlated with NEO-PI-R Impulsiveness and further associated with the GG genotype for both SNPs (P's<0.04). Our results suggest that GABRA2 genetic variation is associated with Impulsiveness through variation of insula activity responses, here evidenced during anticipatory responses.

Genome-wide association scan for five major dimensions of personality.

Personality traits are summarized by five broad dimensions with pervasive influences on major life outcomes, strong links to psychiatric disorders and clear heritable components. To identify genetic variants associated with each of the five dimensions of personality we performed a genome-wide association (GWA) scan of 3972 individuals from a genetically isolated population within Sardinia, Italy. On the basis of the analyses of 362 129 single-nucleotide polymorphisms we found several strong signals within or near genes previously implicated in psychiatric disorders. They include the association of neuroticism with SNAP25 (rs362584, P=5 x 10(-5)), extraversion with BDNF and two cadherin genes (CDH13 and CDH23; Ps<5 x 10(-5)), openness with CNTNAP2 (rs10251794, P=3 x 10(-5)), agreeableness with CLOCK (rs6832769, P=9 x 10(-6)) and conscientiousness with DYRK1A (rs2835731, P=3 x 10(-5)). Effect sizes were small (less than 1% of variance), and most failed to replicate in the follow-up independent samples (N up to 3903), though the association between agreeableness and CLOCK was supported in two of three replication samples (overall P=2 x 10(-5)). We infer that a large number of loci may influence personality traits and disorders, requiring larger sample sizes for the GWA approach to confidently identify associated genetic variants.

Administration of bovine polymerized haemoglobin before and during coronary occlusion reduces infarct size in rabbits.

BACKGROUND: Haemoglobin-based oxygen carriers (HBOC) seem to increase the risk of mortality and myocardial infarction in clinical trials. Therefore, we designed this randomized placebo-controlled animal study to evaluate the effects of prophylactic and therapeutic administration of HBOC in a myocardial ischaemia-reperfusion model with respect to infarct size and areas of impaired perfusion (no reflow, NR). METHODS: Thirty-two anaesthetized, mechanically ventilated rabbits were randomized to one of the four groups. Group G1 received 0.4 g kg(-1) i.v. HBOC-200 25 min before coronary artery occlusion, G2 received the same dose i.v. 10 min after occlusion, and G3 and 4 received i.v. saline. G1, 2, and 3 were subjected to 30 min occlusion of left coronary artery followed by 240 min of reperfusion. G4 was treated without ischaemia-reperfusion. Measurement included assessment of the area at risk and infarct size using triphenyltetrazolium chloride stain and areas of NR using thioflavin stain. Ischaemia-reperfusion was confirmed by microspheres technique. RESULTS: Infarct size as a percentage of the area at risk was significantly reduced in G1 [25 (sd 13)%, P=0.026] and G2 [22 (20)%, P=0.009] compared with G3 [48 (17)%]. The areas of NR in percentage of the area at risk [G1, 26 (15)%; G2, 34 (22)%; G3, 36 (12)%; G4, 5 (3)%] did not differ between the groups of animals undergoing coronary occlusion and reperfusion. CONCLUSIONS: Prophylactic and therapeutic administration of HBOC-200 reduces infarct size in myocardial ischaemia and reperfusion in rabbits. This reduction of infarct size is not accompanied by an improvement of areas of NR.

Effects of a prophylactic or therapeutic application of perflubron emulsion on myocardial ischaemia-reperfusion injury in rats.

BACKGROUND AND OBJECTIVE: The efficacy of administering a perfluorochemical-based oxygen therapeutic such as perflubron emulsion (Oxygen) prior to ischaemia is currently unknown, although there is evidence for potential beneficial effects for the perioperative treatment in cardiac risk patients. This experimental study investigated the efficacy of perflubron emulsion in preventing reperfusion injury and myocardial infarction size after coronary ischaemia and reperfusion. The perflubron emulsion was given either in a prophylactic manner, prior to induction of myocardial ischaemia, or as a therapeutic agent given during ischaemia. METHODS: Thirty-two anaesthetized and mechanically ventilated rats were subjected to 25 min occlusion of the left coronary artery followed by 120 min reperfusion. Animals were randomized to one of four groups:Group 1 was treated with administration of 6 g kg (-1) intravenous perflubron emulsion 25 min before occlusion; Group 2 received the same dose 10 min after occlusion; and Groups 3 and 4 received no perflubron emulsion. Inspired O2 (FiO2) concentration was maintained at 1.0 in Groups 1, 2 and 3 and at 0.35 in Group 4. RESULTS: Neither prophylactic nor therapeutic perflubron emulsion treatment reduced infarct size measurements by triphenyltetrazolium-chloride staining or severity of cardiac arrhythmias in comparison to the hyperoxic control group. However, prophylactic application of perflubron emulsion reduced areas of impaired perfusion vs. Group 3 assessed by in vivo staining with Thioflavin-S while no significant effect was seen in Groups 2 and 4 vs. 3. Density of DNA single-strand breaks in the ventricle was increased in all groups ventilated with 100% oxygen. CONCLUSION: Although administration of perflubron emulsion did not reduce infarct size, areas of impaired perfusion were significantly mitigated when perflubron emulsion was administered prior to coronary occlusion. However, a high oxygen concentration may provoke DNA strand breaks during reperfusion after ischaemia. Further studies must clarify whether enhanced oxidative stress outweighs the advantage of improved areas of impaired perfusion following perflubron emulsion.

Intraoperative anisocoria in a child during renal transplantation.

Anisocoria during anaesthesia may indicate a serious neurological condition. Assessment by physical examination and diagnostic imaging is limited during surgery and anaesthesia. We report a case of a boy undergoing renal transplantation, who suffered from anisocoria during general anaesthesia. A transcranial sonography was performed, showing no intracranial pathology. However, retinal hypoperfusion detected with orbital doppler sonography was a plausible explanation for anisocoria.

HES 130/0.42 shows less alteration of pharmacokinetics than HES 200/0.5 when dosed repeatedly.

BACKGROUND: Hydroxyethyl starches (HES) accumulate in the circulation when administered repeatedly. Accumulation is thought to be partly responsible for undesirable effects (tissue storage, blood coagulation impairment, and itching). HES 130/0.42 with low molecular weight and a low level of substitution has recently been developed in order to reduce those risks. METHODS: In healthy volunteers, the pharmacokinetics of HES 130/0.42/6:1 were investigated using a crossover design with HES 200/0.5 serving as control. Fifty grams of either HES were administered in 4 h day-1 for a period of five consecutive days. HES serum concentrations were used for computation of pharmacokinetic coefficients. Change between the first and fifth infusion in the area under the concentration curve (AUC) served as the primary measurement. RESULTS: Although the circulation was freed from the load with HES 130/0.42 within 20 h after end of the previous infusion, the amount of HES 200/0.5 increased continuously from one administration to the other. AUC and elimination half-life (t1/2) were significantly lower with HES 130/0.42. AUC and t1/2 of HES 200/0.5 showed an increase between the first and the fifth administration whereas only a minimal shift was present with HES 130/0.42. Haemodilution via HES 200/0.5 did not change over time. CONCLUSIONS: Repeated administration of HES 130/0.42 shows no accumulation and fewer tendencies to time-dependent changes in pharmacokinetic parameters than HES 200/0.5. The improved reproducibility may improve drug safety, particularly as the accumulation of residual starch with HES 200/0.5 does not contribute to the colloid's volume effect, but may rather increase the risk of undesired reactions.

Mitochondrial-related gene expression changes are sensitive to agonal-pH state: implications for brain disorders.

Mitochondrial defects in gene expression have been implicated in the pathophysiology of bipolar disorder and schizophrenia. We have now contrasted control brains with low pH versus high pH and showed that 28% of genes in mitochondrial-related pathways meet criteria for differential expression. A majority of genes in the mitochondrial, chaperone and proteasome pathways of nuclear DNA-encoded gene expression were decreased with decreased brain pH, whereas a majority of genes in the apoptotic and reactive oxygen stress pathways showed an increased gene expression with a decreased brain pH. There was a significant increase in mitochondrial DNA copy number and mitochondrial DNA gene expression with increased agonal duration. To minimize effects of agonal-pH state on mood disorder comparisons, two classic approaches were used, removing all subjects with low pH and agonal factors from analysis, or grouping low and high pH as a separate variable. Three groups of potential candidate genes emerged that may be mood disorder related: (a) genes that showed no sensitivity to pH but were differentially expressed in bipolar disorder or major depressive disorder; (b) genes that were altered by agonal-pH in one direction but altered in mood disorder in the opposite direction to agonal-pH and (c) genes with agonal-pH sensitivity that displayed the same direction of changes in mood disorder. Genes from these categories such as NR4A1 and HSPA2 were confirmed with Q-PCR. The interpretation of postmortem brain studies involving broad mitochondrial gene expression and related pathway alterations must be monitored against the strong effect of agonal-pH state. Genes with the least sensitivity to agonal-pH could present a starting point for candidate gene search in neuropsychiatric disorders.

Molar substitution and C2/C6 ratio of hydroxyethyl starch: influence on blood coagulation.

BACKGROUND: Development of hydroxyethyl starches (HES) with a low impact on blood coagulation but a long intravascular persistence is of clinical interest. A previous in vitro study showed that low substituted high molecular weight HES does not compromise blood coagulation more than medium molecular weight HES. In the present study we assessed the individual effects on blood coagulation of molar substitution and C2/C6 ratio of a high molecular weight HES. METHODS: Blood was obtained from 30 healthy patients undergoing elective surgery and mixed with six high molecular weight (700 kDa) HES solutions differing in their molar substitution (0.42 and 0.51) and C2/C6 ratio (2.7, 7 and 14) to achieve 20, 40 and 60% dilution. Blood coagulation was assessed by Thrombelastograph analysis (TEG) and plasma coagulation tests. Data were compared using a three-way analysis of variance model with repeated measures on the three factors. RESULTS: Higher molar substitution compromised blood coagulation most (for all TEG parameters, P<0.05). The lowest C2/C6 ratio was associated with the lowest effect on blood coagulation; r (P<0.001), angle alpha (P=0.003) and coagulation index (P<0.001). No effect on k and maximum amplitude was observed (P for both >0.50). The higher molar substitution was associated with a lesser increase in PT (P=0.007) and a greater decrease in factor VIII (P=0.010). PTT, functional and antigenic von Willebrand factors were not significantly influenced by molar substitution (P for all >0.20). No significant differences between solutions with the same molar substitution but different C2/C6 ratios were found in plasma coagulation parameters (P for all >0.05). CONCLUSIONS: TEG analysis indicates that high molecular HES with a molar substitution of 0.42 and a C2/C6 ratio of 2.7 has the lowest effect on in vitro human blood coagulation.

Effects of prophylactic or therapeutic application of bovine haemoglobin HBOC-200 on ischaemia-reperfusion injury following acute coronary ligature in rats.

BACKGROUND: Haemoglobin-based oxygen carriers (HBOCs) are assessed as blood substitutes in patients with perioperative anaemia including patients at risk for perioperative cardiac ischaemia. There is controversy as to whether HBOCs are beneficial or deleterious during ischaemia-reperfusion (I-R). Therefore the effects of HBOC-200 on I-R injury were evaluated in a randomized placebo-controlled animal trial. METHODS: Animals were randomized to receive either placebo i.v. without I-R (sham group, n=9), placebo i.v. with I-R (control group, n=10), HBOC-200 0.4 g kg(-1) i.v. prior to I-R (prophylaxis group, n=12) or HBOC-200 0.4 g kg(-1) i.v. during I-R (therapy group, n=15). I-R consisted of 25 min of acute ligature of the left coronary artery followed by 120 min of reperfusion. Measurements included assessment of the area at risk and infarct size using triphenyl tetrazolium chloride (TTC) stain, DNA single-strand breaks (in situ nick translation with autoradiography/densitometry) and cardiac arrhythmias. RESULTS: Infarct size within the area at risk was 62 (sd 15)% (control), 46 (10)% (prophylaxis, P<0.025 vs control) and 61 (9)% (therapy, P<0.85 vs control). The frequency of DNA single-strand breaks was reduced vs control in the sham (P<0.01) and prophylaxis (P<0.04) groups and was almost the same in the therapy group (P<0.75). The severity of cardiac arrhythmias during ischaemia was lower compared with control in the sham (P<0.001) and prophylaxis (P<0.039) groups, but there was no difference in the therapy group. CONCLUSION: This study demonstrates that neither prophylactic nor therapeutic application of the cell-free haemoglobin solution HBOC-200 aggravates cardiac I-R injury. Furthermore, the prophylactic approach may offer a new opportunity for pretreatment of patients at risk for perioperative ischaemic cardiac events.

Effects of isovolaemic haemodilution on oxygenation of liver and skeletal muscle.

BACKGROUND AND OBJECTIVE: Hydroxyethyl starch is frequently used for volume substitution during surgical procedures and for isovolaemic haemodilution. Haemodilution has also been shown to improve tissue oxygen tension in skeletal muscle: However, effects of this volume substitute on tissue oxygen tension of the liver during haemodilution remains unknown. METHODS: Fourteen foxhounds were anaesthetized with fentanyl/midazolam and mechanically ventilated with 30% oxygen. Following splenectomy animals were randomly assigned to a control group without haemodilution but fluid substitution with Ringer's lactate (Group C) or underwent isovolaemic haemodilution to a haematocrit of 25% with hydroxyethyl starch 70/0.5 (Group H). Haemodynamic parameters and oxygen transport during 100 min following isovolaemic haemodilution were measured. Liver oxygen tension was recorded using a flexible polarographic electrode tonometer, whereas in the muscle a polarographic needle probe was used. RESULTS: Animal characteristics and baseline haematocrit were similar in both groups. At baseline the tissue oxygen tension of liver and skeletal muscle were not different between groups. Haemodilution with hydroxyethyl starch 70/0.5 provided augmentation of mean liver tissue oxygen tension (baseline: 46 +/- 13 mmHg; 20 min: 60.3 +/- 12 mmHg; 60 min: 60 +/- 16 mmHg; 100 min: 63 +/- 16 mmHg; P < 0.05 vs. baseline), while oxygen tensions in Group C remained unchanged (baseline: 48 +/- 16 mmHg; 20 min: 52 +/- 19 mmHg; 60 min: 49 +/- 12 mmHg; 100 min: 52 +/- 16 mmHg) and no differences could be detected between groups. Oxygen tension in skeletal muscle changed as follows: Group H - baseline: 24 +/- 32 mmHg; 20 min: 32 +/- 3 mmHg; 60 min: 33 +/- 7 mmHg; 100 min: 33 +/- 11 mmHg. Group C - baseline: 22 +/- 6 mmHg; 20 min: 21 +/- 3 mmHg; 60 min: 24 +/- 4 mmHg; 100 min: 18 +/- 4 mmHg (P < 0.05 vs. baseline, p < 0.05 vs. Group C). CONCLUSION: In this animal model, isovolaemic haemodilution with hydroxyethyl starch 70/0.5 increased tissue oxygen tension in liver and skeletal muscle in comparison with baseline values. However, when compared between groups haemodilution only resulted in an increase of tissue oxygen tension in the muscle but not in the liver.

Genetic analysis of the neuronal and ubiquitous AP-3 adaptor complexes reveals divergent functions in brain.

Neurons express adaptor (AP)-3 complexes assembled with either ubiquitous (beta3A) or neuronal-specific (beta3B) beta3 isoforms. However, it is unknown whether these complexes indeed perform distinct functions in neuronal tissue. Here, we explore this hypothesis by using genetically engineered mouse models lacking either beta3A- or beta3B-containing AP-3 complexes. Somatic and neurological phenotypes were specifically associated with the ubiquitous and neuronal adaptor deficiencies, respectively. At the cellular level, AP-3 isoforms were localized to distinct neuronal domains. beta3B-containing AP-3 complexes were preferentially targeted to neuronal processes. Consistently, beta3B deficiency compromised synaptic zinc stores assessed by Timm's staining and the synaptic vesicle targeting of membrane proteins involved in zinc uptake (ZnT3 and ClC-3). Surprisingly, despite the lack of neurological symptoms, beta3A-deficient mouse brain possessed significantly increased synaptic zinc stores and synaptic vesicle content of ZnT3 and ClC-3. These observations indicate that the functions of beta3A- and beta3B-containing complexes are distinct and divergent. Our results suggest that concerted nonredundant functions of neuronal and ubiquitous AP-3 provide a mechanism to control the levels of selected membrane proteins in synaptic vesicles.

[Plasma levels of ropivacaine and bupivacaine during postoperative patient controlled thoracic epidural analgesia]. / Plasmakonzentrationen von Ropivacain und Bupivacain während postoperativer Patienten-kontrollierter thorakaler Epiduralanalgesie.

BACKGROUND: The postoperative continuous epidural application of local anesthetics can cause side effects like motor blockade and systemic intoxication. The study was performed to evaluate the plasma levels of two local anesthetics and their analgesic and side effects in continuous postoperative epidural analgesia. METHODS: In a prospective, randomized and double-blind study we have compared side effects of ropivacaine 0.375% (group R) vs. bupivacaine 0.125% in combination with sufentanil 0.5 microg ml(-1) (group B/S) via thoracic epidural catheters for a duration of 96 hours after major abdominal surgery in 30 gynaecological tumor patients. Analgesic effects, side effects and plasma levels of the respective local anesthetic were measured 24, 48, 72 and 96 h after start of epidural infusion. RESULTS: No differences were seen in demographics, perioperative data and analgesic effects. The following cumulative doses of local anesthetics were applied (Group R vs. B/S (median/minimum-maximum ml)): 24 h: 151/121-225 vs. 141/83-171; 48 h: 311/237-424 vs. 299/184-497; 72 h: 454/366-566 vs. 440/256-598; 96 h: 572/399-859 vs. 568/284-711. Plasma levels of local anesthetics remained far below the toxic threshold of 0.6 micro g/ml (Group R vs. B/S (median/minimum-maximum micro g/ml): 24 h: 0.05/0.03-0.24 vs. 0.0/0.0-0.02; 48 h: 0.06/0.02-0.15 vs. 0.006/0.0-0.02; 72 h: 0.05/0.0-0.11 vs. 0.0/0.0-0.02; 96 h: 0.02/0.01-0.32 vs. 0.0/0.0-0.01). The incidence and intensity of motor block (Bromage scale) and other side effects did also not differ between groups. CONCLUSION: The present study shows that thoracic epidural infusion with bupivacaine 0.125% and with a higher concentration of ropivacaine 0.375% during 96 h provides plasma levels of unbound local anesthetic far below the toxic threshold.

Acute heart failure during spinal surgery in a boy with Duchenne muscular dystrophy.

Patients with Duchenne muscular dystrophy (DMD) are at high risk of perioperative complications. DMD may be accompanied by heart failure resulting from dystrophic involvement of the myocardium, which can be subclinical in the early stages of the disease. This case demonstrates that a normal preoperative ECG and echocardiograph cannot exclude the development of heart failure during anaesthesia in DMD patients undergoing major surgery.

Hemoglobin-based oxygen carrier HBOC-201 provides higher and faster increase in oxygen tension in skeletal muscle of anemic dogs than do stored red blood cells.

BACKGROUND: Increasing need for and potential shortage of blood products have intensified the search for alternative oxygen carriers. A solution to this problem could be use of the bovine hemoglobin-based oxygen carrier HBOC-201. While hemodynamic reactions to cell-free hemoglobin have been studied, little knowledge exists about tissue oxygenation properties of hemoglobin solutions, especially in comparison with red blood cells (RBCs). STUDY DESIGN AND METHODS: Tissue oxygenation in skeletal muscle of 12 anesthetized dogs was examined after decrease of hemoglobin concentrations by means of hemodilution to hematocrit 10% and subsequent transfusion with either HBOC-201 or autologous banked RBCs. In addition to hemodynamic parameters, blood gas concentrations and oxygen content in arterial and muscular venous blood, tissue oxygen tension (tPO(2)) were measured in the gastrocnemius muscle with a polarographic needle probe. RESULTS: Hemodilution increased muscular blood flow and oxygen extraction and decreased tPO(2). Transfusion decreased muscular oxygen extraction in the RBC group but not in the HBOC-201 group (P <.01). The 10th percentile of tPO(2) increased by 400% after the first dose of HBOC-201 (P <.001 vs posthemodilution) but only by 33% after equivalent RBC transfusion (P <.01 vs HBOC-201). Increases in the 50th (120%, P <.05) and 90th (31%) percentiles and all percentiles of tPO(2) after the second and third HBOC-201 dose were less pronounced but higher than in the RBC group. CONCLUSION: Compared with RBC transfusion, infusion of low doses of HBOC-201 maintain enhanced oxygen extraction after extended hemodilution and provide faster and higher increase in muscular tissue PO(2).