bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of ABO incompatibility on allogeneic peripheral blood progenitor cell transplantation after reduced intensity conditioning
Authors: Canals Carmen , Muñiz‐Díaz Eduardo , Martínez Clara , Martino Rodrigo , Moreno Imma , Ramos Adelaida , Arilla Marina , Boto Neus , Pastoret Concepción , Remacha Angel , Sierra Jorge , Madoz Pedro
Published: October 2004

BACKGROUND:  Most studies indicate that ABO incompatibility has no effect on the clinical outcome after allogeneic peripheral blood progenitor cell (PBPC) transplantation (allo‐PBPCT). However, it carries additional risks of hemolytic reactions, delayed red blood cell (RBC) engraftment, and pure red cell aplasia (PRCA). Data on these events after reduced intensity conditioning (RIC) regimens are limited, but recent studies have suggested a higher transplant‐related mortality (TRM) and morbidity in this setting.

STUDY DESIGN AND METHODS:  We investigated the impact of ABO‐matching on the outcome of 77 patients included in a prospective RIC allo‐PBPCT protocol, focusing on engraftment, transfusion requirements, graft‐versus‐host disease, TRM, and survival.

RESULTS:  There were 17 (22%) minor and 8 (10%) major ABO‐incompatible transplants. No graft failures were observed. After major ABO‐incompatible grafts, RBC engraftment was delayed, longer thrombocytopenia periods were documented, and transfusion requirements increased. A transient mild hemolysis occurred in 10 patients, 7 (41%) minor and 3 (37%) major ABO‐mismatched. A PRCA was observed in a O+ patient with a pretransplant anti‐Jka, grafted from an A + Jka+ donor. Graft‐versus‐host disease, disease progression, and TRM were not affected by ABO matching.

CONCLUSION:  ABO incompatibility was not associated with clinically relevant hemolysis after the RIC protocol used and did not impair the clinical outcome. PRCA was only observed in one patient, with a non‐ABO RBC allo‐antibody.
Complications of double‐filtration plasmapheresis
Authors: Yeh Jiann‐Horng , Chen Wei‐Hung , Chiu Hou‐Chang
Published: October 2004

BACKGROUND:  Double‐filtration plasmapheresis (DFP) removes high‐molecular‐weight molecules semiselectively, thereby minimizing albumin loss, but with subsequent need for fluid substitution. The purpose of this study was to establish the overall incidence of complications during DFP and to analyze the possible contributory factors.

STUDY DESIGN AND METHODS:  From November 1993 to October 2003, a total of 2502 plasmapheresis procedures were performed during 515 courses of plasmapheresis in 335 patients. The medical and technical records for these patients were reviewed.

RESULTS:  The overall frequency of complications was 67.5 percent per patient, 60.0 percent per course, and 26.3 percent per procedure. The rate of major complications was 18.2 percent of patients, 13.2 percent of courses, and 2.7 percent of procedures. Hemolysis, the most common complication of DFP, occurred in 20 percent of patients. A total of 83 (3.3%) episodes of hypotension were documented in 63 patients. Vascular‐access‐related complications constituted approximately 17 percent of the total. There was one documented episode of clinically overt bleeding from laboratory coagulopathy necessitating infusion of fresh plasma to stop bleeding. There was no allergic reaction or mortality associated with the DFP procedures. The per‐patient frequency of hypotension was higher in cases of chronic inflammatory neuropathy (35.1%) compared to the other illness categories (15.4%‐17.3%), with marginal significance demonstrated (p = 0.0611).

CONCLUSION:  The safety of DFP treatment has been confirmed by this study. High‐risk patients should be monitored carefully during treatment to minimize the occurrence of complications.
Immune responsiveness against allogeneic platelet transfusions is determined by the recipient's major histocompatibility complex class II phenotype
Authors: Sayeh Ebrahim , Aslam Rukshana , Speck Edwin R. , Le‐Tien Hoang , Lazarus Alan H. , Freedman John , Semple John W.
Published: October 2004

BACKGROUND:  Immunoglobulin G (IgG) anti‐platelet (PLT) immunity has been shown to be initiated by indirect allorecognition where recipient T cells recognize donor PLT antigens presented by class II molecules encoded by the major histocompatibility complex (MHC) on recipient antigen‐presenting cells. To understand how the recipient's MHC class II molecules may influence PLT alloimmunity, immune responsiveness against transfused PLTs was tested in different mouse strains.

STUDY DESIGN AND METHODS:  Various inbred and mutant mouse strains were transfused with allogeneic PLTs and IgG donor antibodies were measured by flow cytometry.

RESULTS:  When recipient mice, expressing both MHC class II I‐A and MHC class II I‐E molecules, were transfused weekly with allogeneic PLTs, high titers of IgG donor antibodies were generated. In comparison, however, recipient mice expressing only MHC class II I‐A molecules had significantly (p < 0.001) reduced IgG antibody responsiveness against PLT transfusions. The low IgG responder status against allogeneic PLT transfusions was rescued in transgenic mice expressing I‐E molecules and in mice genetically deficient in either β2‐microglobulin or CD8+ T cells.

CONCLUSION:  IgG immune responsiveness against allogeneic PLT transfusions is dependent on recipient expression of I‐E MHC class II molecules, whereas I‐A expression is linked with CD8‐mediated suppression of PLT immunity. The data suggest that strategies to modify recipient MHC class II presentation of donor PLT antigens would be effective in eliminating PLT alloimmunity.
Metabolic Effects of Propofol in the Isolated Perfused Rat Liver
Authors: Acco Alexandra , Comar Jurandir Fernando , Bracht Adelar
Published: October 2004

Abstract: Inhibitory effects of the intravenous anaesthetic propofol on mitochondrial energy metabolism have been reported by several authors. Impairment of energy metabolism is usually coupled to reduction in ATP production, which in turn is expected to lead to several alterations in cell metabolism such as stimulation of glycolysis and inhibition of gluconeogenesis. The present work aimed at finding an answer to the question of how propofol affects energy metabolism‐linked parameters in the isolated perfused rat liver. In the fed state, propofol increased glycogenolysis (glucose release), glycolysis (lactate and pyruvate production) and oxygen uptake in the range between 10 and 500 μM. In the liver of fasted rats, propofol up to 100 μM increased oxygen uptake but decreased gluconeogenesis from three different substrates: lactate, alanine and glycerol. When lactate was the substrate 50% inhibition occurred at a propofol concentration of 50 μM. Propofol (100 μM) decreased the ATP content of the liver (−33.3%), increased the AMP content (+25%) and decreased the ATP/ADP and ATP/AMP ratios (49 and 45%, respectively). Most effects of propofol are probably due to impairment of oxidative phosphorylation. Particularly, the combined differential action on oxygen uptake (stimulation) and gluconeogenesis (inhibition) is strongly suggestive of an uncoupling action also under the conditions of the intact cell. This effect, in turn, is consistent with the reported high affinity of the cellular hepatic structure, especially membranes, for propofol.
The Effect of Tamoxifen and Fluoride on Bone Mineral Density, Biomechanical Properties and Blood Lipids in Ovariectomized Rats
Authors: Czerny Bogusław , Pawlik Andrzej , Juzyszyn Zygmunt , Myśliwiec Zofia
Published: October 2004

Abstract: The most important aspect of therapy with fluoride and tamoxifen concerns its influence on bone tissue and lipid metabolism. The aim of the study was to evaluate the effect of tamoxifen and natrium fluoride (NaF) on bone metabolism, biochemical properties and blood lipids levels in ovariectomized rats. The study was performed in Wistar rats divided into 5 subgroups: ovariectomized controls, rats treated with NaF 20 mg/kg/24 hr, rats treated with NaF 20 mg/kg/24 hr+tamoxifen 2 mg/kg/24 hr, rats treated with NaF 20 mg/kg/24 hr plus tamoxifen 4 mg/kg/24 hr, and sham‐operated controls. In ovariectomized rats the increase of total cholesterol, low‐density lipoproteins cholesterol (LDL‐cholesterol) as well as the decrease of bone mineral content, bone mineral density and biomechanical properties was observed. The therapy with NaF increased the level of total cholesterol, LDL‐cholesterol, triglycerides, bone mineral density, bone mineral content. In this group the decrease of bone strength and stiffness was observed. The administration of tamoxifen reduced the changes in plasma lipid levels, but did not improve the biomechanical properties of bone tissue.
The Presynaptic Activity of Bothropstoxin‐I, a Myotoxin from Bothrops jararacussu Snake Venom
Authors: Oshima‐Franco Yoko , Leite Gildo Bernardo , Belo Cháriston André Dal , Hyslop Stephen , Prado‐Franceschi Júlia , Cintra Adélia Cristina Oliveira , Giglio José Roberto , Da Cruz‐Höfling Maria Alice , Rodrigues‐Simioni Léa
Published: October 2004

Abstract: Bothropstoxin‐I from Bothrops jararacussu snake venom is a lysine‐49 phospholipase A2 with myotoxic and neurotoxic activities. In this study, we used mouse phrenic nerve‐diaphragm preparations in the absence and presence of manganese (Mn2+), a presynaptic blocker, to investigate a possible presynaptic action of bothropstoxin‐I. At concentrations of 0.9 mM and 1.8 mM, Mn2+ produced 50% neuromuscular blockade in less than 4 min., which was spontaneously reversible at the lower concentration. Bothropstoxin‐I (1.4 μM) irreversibly inhibited neuromuscular blockade by 50% in 31±4 min. (mean±S.E.M., n=9). Pretreating preparations with 0.9 mM Mn2+ prevented the blockade by bothropstoxin‐I. When added after bothropstoxin‐I, Mn2+ produced its characteristic blockade and, after washing, the twitch tension returned to pre‐Mn2+ levels, indicating that bothropstoxin‐I caused irreversible damage before the addition of Mn2+. Electrophysiological measurements showed that a concentration of bothropstoxin‐I (0.35 μM), which did not produce neuromuscular blockade, caused the appearance of giant miniature end‐plate potentials with no change in the membrane resting potential but increased the quantal content. Preparations preincubated with Mn2+ (0.9 mM, 30 min.) were protected against the depolarizing action of bothropstoxin‐I (0.7 μM). These results show that, in addition to its well‐known myotoxic effect, bothropstoxin‐I also has a presynaptic action.
In vitro Cytotoxicity of Epigallocatechin Gallate and Tea Extracts to Cancerous and Normal Cells from the Human Oral Cavity
Authors: Weisburg Jeffrey H. , Weissman Danielle B. , Sedaghat Tannaz , Babich Harvey
Published: October 2004

Abstract: This study compared the in vitro responses of malignant and normal cells from the human oral cavity to tea extracts and to its main polyphenolic component, (−)‐epigallocatechin gallate (EGCG). The antiproliferative effects of tea polyphenolic extracts and EGCG were more pronounced towards immortalized, tumourigenic (CAL27, HSC‐2, and HSG1) and non‐tumourigenic (S‐G) cells than towards normal (GN56 and HGF‐1) fibroblasts and green tea was more toxic than black tea. As the addition of tea extract or EGCG to cell culture medium led to the formation of hydrogen peroxide (H2O2), the research then focused on EGCG as an inducer of oxidative stress, using CAL27, the cancerous cells most sensitive to EGCG, HSG1, the cancerous cells least sensitive to EGCG, and GN56 cells. The toxicity of EGCG was decreased in the presence of catalase, an enzyme that degrades H2O2, or of deferoxamine, a chelator of Fe3+. Conversely, pretreatment of the cells with the glutathione depleters, 1‐chloro‐2,4‐dinitrobenzene and 1,3‐bis(2‐chloroethyl)‐N‐nitrosourea, potentiated the toxicity of EGCG. A 4‐hr exposure to EGCG lessened the intracellular level of reduced glutathione in the CAL27 and HSG1 cells, but not in the GN56 fibroblasts. Whereas EGCG itself did not induce lipid peroxidation, Fe2+‐induced lipid peroxidation was potentiated by EGCG. A 72‐hr exposure to cytotoxic concentrations of EGCG induced significant cytoplasmic vacuolization in all cell types. The results presented herein are consistent with EGCG acting as a prooxidant, with the cancerous cells more sensitive to oxidative stress than the normal cells.
Induction of striatal long‐term synaptic depression by moderate frequency activation of cortical afferents in rat
Authors: Ronesi Jennifer , Lovinger David M.
Published: October 2004

The striatum regulates motor output, and it is thought that changes in the synaptic efficacy of inputs to the striatum contribute to motor learning and habit formation. Previously, several laboratories have observed that brief high frequency stimulation (HFS) of cortical afferents innervating the dorsolateral striatum induces a long‐term decrease in synaptic efficacy called long‐term depression (LTD). We recently showed that HFS‐induced striatal LTD requires retrograde signalling involving postsynaptic release of endocannabinoids and activation of presynaptic CB1 cannabinoid receptors. In the present study we have employed whole‐cell recording in brain slices to examine a new form of LTD at corticostriatal synapses that can be induced by a 10 Hz, 5 min train. The decrease in synaptic efficacy is associated with a decrease in presynaptic release probability, as demonstrated by a decrease in frequency but not amplitude of spontaneous excitatory postsynaptic currents (sEPSCs) and an increase in the paired pulse ratio (PPR). This form of LTD is blocked by antagonists for CB1 and D2 dopamine receptors and impaired by blockers of L‐type calcium channels. However, 10 Hz‐induced LTD does not depend on postsynaptic depolarization, unlike HFS‐induced LTD. Furthermore, this new form of LTD is not prevented by treatments known to block HFS‐induced LTD, including antagonism of metabotropic glutamate receptors (mGluRs), chelation of postsynaptic calcium, or intracellular application of an anandamide membrane transport inhibitor (VDM11). From these findings it is not clear that the endocannabinoid responsible for this form of LTD acts in a retrograde fashion, and the cellular source of endocannabinoid necessary for 10 Hz‐induced LTD is as yet unknown. Our results demonstrate that a prolonged moderate frequency train induces cannabinoid‐dependent LTD, further supporting the idea that endocannabinoids play a prominent role in the regulation of long‐lasting changes in striatal output.
Acetyl group availability influences phosphocreatine degradation even during intense muscle contraction
Authors: Timmons James A. , Constantin‐Teodosiu Dumitru , Poucher Simon M. , Greenhaff Paul L.
Published: October 2004

We previously established that activation of the pyruvate dehydrogenase complex (PDC) using dichloroacetate (DCA) reduced the reliance on substrate‐level phosphorylation (SLP) at the onset of exercise, with normal and reduced blood flow. PDC activation also reduced fatigue development during contraction with reduced blood flow. Since these observations, several studies have re‐evaluated our observations. One study demonstrated a performance benefit without a reduction in SLP, raising a question mark over PDC's role in the regulation of ATP regeneration and our interpretation of fatigue mechanisms. Using a model of muscle contraction similar to the conflicting study (i.e. tetanic rather than twitch stimulation), we re‐examined this question. Using canine skeletal muscle, one group was infused with saline while the other was pretreated with 300 mg (kg body mass)−1 DCA. Muscle biopsies were taken at rest, peak tension (1 min) and after 6 min of tetanic electrical stimulation (75 ms on−925 ms off per second) and blood flow was limited to 25% of normal values observed during contraction. DCA reduced phosphocreatine (PCr) degradation by 40% during the first minute of contraction, but did not prevent the almost complete depletion of PCr stores at 6 min, while muscle fatigue did not differ between the two groups. During intermittent tetanic stimulation PCr degradation was 75% greater than with our previous 3 Hz twitch contraction protocol, despite a similar rate of oxygen consumption at 6 min. Thus, in the present study enhanced acetyl group availability altered the time course of PCr utilization but did not prevent the decline towards depletion. Consistent with our earlier conclusions, DCA pretreatment reduces muscle fatigue only when SLP is attenuated. The present study and our met‐analysis indicates that enhanced acetyl group availability results in a readily measurable reduction in SLP when the initial rate of PCr utilization is ∼1 mmol (kg dry mass)−1 s−1 or less (depending on intrinsic mitochondrial capacity). When measured early during an uninterrupted period of muscle contraction, acetyl group availability is likely to influence SLP under any condition where mitochondria are responsible for a significant proportion of ATP regeneration.
Prostaglandins participate in the late phase of the vascular response to acetylcholine iontophoresis in humans
Authors: Durand S. , Tartas M. , Bouyé P. , Koïtka A. , Saumet J. L. , Abraham P.
Published: October 2004

The participation of prostaglandins (PGs) in the cutaneous vasodilatation to acetylcholine (ACh) applied via iontophoresis is under debate. Using laser Doppler flowmetry, we studied the long lasting effect (20 min) of iontophoretic application (30 s; 0.1 mA) of ACh on the human forearm. Experiments were repeated (1) using deionized water instead of ACh to test the effect of current application, (2) after scopolamine treatment to inhibit muscarinic cholinergic receptors, and (3) 2 h, 3 days and 10 days following inhibition of PG synthesis with aspirin or a placebo control. Cutaneous vascular conductance (CVC) was calculated at rest (CVCrest), at peak vasodilatation in the first 5 min following ACh iontophoresis (CVCpeak), and 20 min after iontophoresis (CVC20). The minimal CVC (CVCmin) following iontophoresis was also determined. Cutaneous response to ACh displayed a biphasic pattern with an early and transient peak (CVCpeak: 62 ± 8% of the maximal CVC induced by local heating (MVC)) followed by a long lasting slower vasodilatation (CVCmin: 44 ± 6; CVC20: 56 ± 5%MVC). The current itself had no major effect. Scopolamine almost abolished both phases. The long lasting phase was aspirin sensitive but not the transient phase. At hour 2 post‐aspirin, CVCpeak was 61 ± 10, CVCmin 26 ± 6 and CVC20 29 ± 6%MVC. At day 3, CVCpeak was 53 ± 9, CVCmin 22 ± 3 and CVC20 25 ± 4%MVC. At day 10, CVCpeak was 67 ± 10, CVCmin 47 ± 7 and CVC20 50 ± 8%MVC. Placebo had no effect. We conclude that PGs participate in the vasodilator response following ACh iontophoresis. Previous non‐steroidal anti‐inflammatory drug treatments must be taken into account when studying the effect of ACh iontophoresis.
Persistent changes in the intrinsic excitability of rat deep cerebellar nuclear neurones induced by EPSP or IPSP bursts
Authors: Zhang Wei , Shin Jung Hoon , Linden David J.
Published: October 2004

The deep cerebellar nuclei (DCN) are the major output of the cerebellum, and have been proposed as a site of memory storage for certain forms of motor learning. Microelectrode and whole‐cell patch recordings were performed on DCN neurones in acute slices of juvenile rat cerebellum. DCN neurones display tonic and bursting basal firing patterns. In tonically firing neurones, a stimulus consisting of EPSP bursts produced a brief increase in dendritic Ca2+ concentration and a persistent increase in the number of spikes elicited by a depolarizing test pulse, along with a decrease in spike threshold. In intrinsically bursting DCN neurones, EPSP bursts induced an increase in the number of depolarization‐evoked spikes in some neurones, but in others produced a change to a more tonic firing pattern. Application of IPSP bursts evoked a large number of rebound spikes and an associated dendritic Ca2+ transient, which also produced a persistent increase in the number of spikes elicited by a test pulse. Intracellular perfusion of the Ca2+ chelator BAPTA prevented the increase in intrinsic excitability. Thus, rapid changes in intrinsic excitability in the DCN may be driven by bursts of both EPSPs and IPSPs, and may result in persistent changes to both firing frequency and pattern.
Augmented sympathetic vasoconstriction in exercising forearms of postmenopausal women is reversed by oestrogen therapy
Authors: Fadel Paul J. , Wang Zhongyun , Watanabe Hitoshi , Arbique Debbie , Vongpatanasin Wanpen , Thomas Gail D.
Published: October 2004

Sympathetic vasoconstriction is normally attenuated in exercising muscles of young men and women. Recent evidence indicates that such modulation, termed functional sympatholysis, may be impaired in older men. Whether a similar impairment occurs in older women, and what role oestrogen deficiency might play in this impairment, are not known. Based on the strong positive correlation between circulating oestrogen levels and functional sympatholysis previously reported in female rats, we hypothesized that sympatholysis would be impaired in oestrogen‐deficient postmenopausal women, and that this impairment would be reversed by oestrogen replacement. To test these hypotheses, we measured vasoconstrictor responses in the forearms of pre‐ and postmenopausal women using near infrared spectroscopy to detect decreases in muscle oxygenation in response to reflex activation of sympathetic nerves evoked by lower body negative pressure (LBNP). In eight premenopausal women, LBNP decreased muscle oxygenation by 20 ± 1% in resting forearm, but only by 3 ± 2% in exercising forearm (P < 0.05). In contrast, in eight postmenopausal women, LBNP decreased muscle oxygenation by 15 ± 3% in resting forearm, and by 12 ± 4% in exercising forearm (P > 0.05). After 1 month of transdermal oestradiol replacement in these women, the normal effect of exercise to blunt sympathetic vasoconstriction was restored (rest, −19 ± 3%; exercise, −2 ± 3%; P < 0.05). These data indicate that functional sympatholysis is impaired in oestrogen‐deficient postmenopausal women. The effect of short‐term unopposed oestrogen replacement to correct this impairment implicates a role for oestrogen in the sympathetic neural control of muscle haemodynamics during exercise.
Specific pattern of ionic channel gene expression associated with pacemaker activity in the mouse heart
Authors: Marionneau Céline , Couette Brigitte , Liu Jie , Li Huiyu , Mangoni Matteo E. , Nargeot Joël , Lei Ming , Escande Denis , Demolombe Sophie
Published: October 2004

Even though sequencing of the mammalian genome has led to the discovery of a large number of ionic channel genes, identification of the molecular determinants of cellular electrical properties in different regions of the heart has been rarely obtained. We developed a high‐throughput approach capable of simultaneously assessing the expression pattern of ionic channel repertoires from different regions of the mouse heart. By using large‐scale real‐time RT‐PCR, we have profiled 71 channels and related genes in the sinoatrial node (SAN), atrioventricular node (AVN), the atria (A) and ventricles (V). Hearts from 30 adult male C57BL/6 mice were microdissected and RNA was isolated from six pools of five mice each. TaqMan data were analysed using the threshold cycle (Ct) relative quantification method. Cross‐contamination of each region was checked with expression of the atrial and ventricular myosin light chains. Two‐way hierarchical clustering analysis of the 71 genes successfully classified the six pools from the four distinct regions. In comparison with the A, the SAN and AVN were characterized by higher expression of Navβ1, Navβ3, Cav1.3, Cav3.1 and Cavα2δ2, and lower expression of Kv4.2, Cx40, Cx43 and Kir3.1. In addition, the SAN was characterized by higher expression of HCN1 and HCN4, and lower expression of RYR2, Kir6.2, Cavβ2 and Cavγ4. The AVN was characterized by higher expression of Nav1.1, Nav1.7, Kv1.6, Kvβ1, MinK and Cavγ7. Other gene expression profiles discriminate between the ventricular and the atrial myocardium. The present study provides the first genome‐scale regional ionic channel expression profile in the mouse heart.
Voltage‐dependent calcium entry underlies propagation of slow waves in canine gastric antrum
Authors: Ward Sean M. , Dixon Rose Ellen , De Faoite Andrew , Sanders Kenton M.
Published: October 2004

Electrical slow waves in gastrointestinal (GI) muscles are generated by interstitial cells of Cajal (ICC), and these events actively propagate through networks of ICC within the walls of GI organs. The mechanism by which spontaneously active pacemaker sites throughout ICC networks are entrained to produce orderly propagation of slow waves is unresolved. A three‐chambered partition bath was used to test the effects of agents that affect metabolism, membrane potential and voltage‐dependent Ca2+ entry on slow wave propagation in canine antral smooth muscle strips. Slow waves evoked by electrical field stimulation actively propagated from end to end of antral muscle strips with a constant latency between two points of recording. When the central chamber of the bath was perfused with low‐temperature solutions, mitochondrial inhibitors, reduced extracellular Ca2+ or blockers of voltage‐dependent Ca2+ channels, active propagation failed. Depolarization or hyperpolarization of the tissue within the central chamber also blocked propagation. Blockade of propagation by reduced extracellular Ca2+ and inhibitors of dihydropyridine‐resistant Ca2+ channels suggests that voltage‐dependent Ca2+ entry may be the ‘entrainment factor’ that facilitates active propagation of slow waves in the gastric antrum.
SYMPOSIUM REPORT. Background synaptic activity in rat entorhinal cortical neurones: differential control of transmitter release by presynaptic receptors
Authors: Jones Roland S. G. , Woodhall Gavin L.
Published: October 2004

The entorhinal cortex (EC) is a key brain area controlling both hippocampal input and output via neurones in layer II and layer V, respectively. It is also a pivotal area in the generation and propagation of epilepsies involving the temporal lobe. We have previously shown that within the network of the EC, neurones in layer V are subject to powerful synaptic excitation but weak inhibition, whereas the reverse is true in layer II. The deep layers are also highly susceptible to acutely provoked epileptogenesis. Considerable evidence now points to a role of spontaneous background synaptic activity in control of neuronal, and hence network, excitability. In the present article we describe results of studies where we have compared background release of the excitatory transmitter, glutamate, and the inhibitory transmitter, GABA, in the two layers, the role of this background release in the balance of excitability, and its control by presynaptic auto‐ and heteroreceptors on presynaptic terminals.
The combined effects of exercise and food intake on adipose tissue and splanchnic metabolism
Authors: Enevoldsen L. H. , Simonsen L. , Macdonald I. A. , Bülow J.
Published: October 2004

Seven young, healthy male subjects were each studied in two separate experiments. (1) Subjects exercised for 60 min at 55% of peak oxygen consumption in the fasted state ending 30 min before a meal (60% of energy as carbohydrate, and 20% of energy as lipid and protein each) comprising 25% of the total daily energy intake, and were then studied for another 150 min postprandially during rest (E→M). (2) One hour after a similar meal, subjects exercised for 60 min and were then studied for another 180 min postexercise during rest (M→E). Regional adipose tissue and splanchnic tissue metabolism were measured by Fick's Principle. Food intake before exercise reduced whole‐body lipid combustion during exercise to about 50% of the combustion rate found during exercise in the fasted state. The increase in subcutaneous, abdominal adipose tissue lipolysis during exercise was not influenced by preexercise food intake, while the fatty acid mobilization was increased by only 1.5‐fold during postprandial exercise compared to a fourfold increase during exercise in the fasted state. During exercise, catecholamine concentrations increased similarly in the fasted and the postprandial state, while the insulin concentration was twofold higher postprandially. These results indicate that the increase in catecholamine concentrations during exercise is a more important determinant of the adipose tissue lipolytic rate than the decrease in insulin concentration. Furthermore, food intake either 30 min after or 1 h before exercise prevents the postexercise increase in adipose tissue glycerol and fatty acid release which normally takes place in fasting subjects at least up to 2.5 h postprandially. Postprandial exercise led to a faster increase in postprandial lipaemia. This could not be accounted for by changes in the regional splanchnic tissue or adipose tissue triacylglycerol metabolism. Exercise was able to increase hepatic glucose production irrespective of food intake before exercise. It is concluded that exercise performed in the fasted state shortly before a meal leads to a more favourable lipid metabolism during and after exercise than exercise performed shortly after a meal.
Stratum oriens horizontal interneurone diversity and hippocampal network dynamics
Authors: Maccaferri Gianmaria
Published: October 2004

In this last decade, the combination of differential interference contrast infrared video technology and patch‐clamp techniques applied to slices in vitro has allowed the routine electrophysiological recording of visually identified central neurones. This has opened the way to the possibility of preselecting GABAergic interneurones of the hippocampus on the basis of some peculiar morphological characteristics. In particular, stratum oriens ‘horizontal’ interneurones are easily recognizable in living hippocampal slices because of their location and bipolar/bitufted appearance. Thus, this class of cells has rapidly risen as one of the most studied in the entire hippocampus. In this review, I will try to assemble the vast electrophysiological knowledge on these interneurones into a more focused picture, which is relevant for network activity in vitro and in vivo.
Slc26a6: a cardiac chloride–hydroxyl exchanger and predominant chloride–bicarbonate exchanger of the mouse heart
Authors: Alvarez Bernardo V. , Kieller Dawn M. , Quon Anita L. , Markovich Daniel , Casey Joseph R.
Published: October 2004

Bicarbonate facilitate more than 50% of pH recovery in the acidotic myocardium, and have roles in cardiac hypertrophy and steady‐state pH regulation. To determine which bicarbonate transporters are responsible for this activity, we measured the expression levels of all known HCO3−–anion exchange proteins in mouse heart, by quantitative real time RT‐PCR. Bicarbonate–anion exchangers are members of either the SLC4A or the SLC26A gene families. In neonatal and adult myocardium, AE1 (Slc4a1), AE2 (Slc4a2), AE3 (Slc4a3) (AE3fl and AE3c variants), Slc26a3 and Slc26a6 were expressed. Adult hearts expressed Slc26a3 and Slc4a1–3 mRNAs at similar levels, while Slc26a6 mRNA was about seven‐fold higher than AE3, which was more abundant than any other. Immunohistochemistry revealed that Slc26a6 and AE3 are present in the plasma membrane of ventricular myocytes. Slc26a6 expression levels were higher in ventricle than atrium, whereas AE3 was detected only in ventricle. Cl−–HCO3− and Cl−–OH− exchange activity of SLC26A6 and AE3 were investigated in transfected HEK293 cells, using intracellular fluorescence measurements of 2′,7′‐bis (2‐carboxyethyl)‐5(6)‐carboxyfluorescein (BCECF), to monitor intracellular pH (pHi). Rates of pHi change were measured under HCO3−‐containing (Cl−–HCO3−) or nominally HCO3−‐free (Cl−–OH−) conditions. HCO3− fluxes were similar for cells expressing AE3fl, SLC26A6 or Slc26a3, suggesting that they have similar transport activity. However, only SLC26A6 and Slc26a3 functioned as Cl−–OH− exchangers. Activation of α‐adrenergic receptors, which stimulates protein kinase C, inhibited SLC26A6 Cl−–HCO3− exchange activity. We conclude that Slc26a6 is the predominant Cl−–HCO3− and Cl−–OH− exchanger of the myocardium and that Slc26a6 is negatively regulated upon α‐adrenergic stimulation.
Compensated Deleterious Mutations in Insect Genomes
Authors: Kulathinal Rob J. , Bettencourt Brian R. , Hartl Daniel L.
Published: October 2004

Relatively little is known about the importance of amino acid interactions in protein and phenotypic evolution. Here we examine whether mutations that are pathogenic in
Drosophila melanogaster
become fixed via epistasis in other Dipteran genomes. Overall divergence at pathogenic amino acid sites is reduced. However, ∼10% of the substitutions at these sites carry the exact same pathogenic amino acid found in
D. melanogaster
mutants. Hence compensatory mutation(s) must have evolved. Surprisingly, the fraction 10% is not affected by phylogenetic distance. These results support a selection-driven process that allows compensated amino acid substitutions to become rapidly fixed in taxa with large populations.
A Cluster of Metabolic Defects Caused by Mutation in a Mitochondrial tRNA
Authors: Wilson Frederick H. , Hariri Ali , Farhi Anita , Zhao Hongyu , Petersen Kitt Falk , Toka Hakan R. , Nelson-Williams Carol , Raja Khalid M. , Kashgarian Michael , Shulman Gerald I. , Scheinman Steven J. , Lifton Richard P.
Published: October 2004

Hypertension and dyslipidemia are risk factors for atherosclerosis and occur together more often than expected by chance. Although this clustering suggests shared causation, unifying factors remain unknown. We describe a large kindred with a syndrome including hypertension, hypercholesterolemia, and hypomagnesemia. Each phenotype is transmitted on the maternal lineage with a pattern indicating mitochondrial inheritance. Analysis of the mitochondrial genome of the maternal lineage identified a homoplasmic mutation substituting cytidine for uridine immediately 5′ to the mitochondrial transfer RNA
Ile
anticodon. Uridine at this position is nearly invariate among transfer RNAs because of its role in stabilizing the anticodon loop. Given the known loss of mitochondrial function with aging, these findings may have implications for the common clustering of these metabolic disorders.
The Roaming Atom: Straying from the Reaction Path in Formaldehyde Decomposition
Authors: Townsend D. , Lahankar S. A. , Lee S. K. , Chambreau S. D. , Suits A. G. , Zhang X. , Rheinecker J. , Harding L. B. , Bowman J. M.
Published: October 2004

We present a combined experimental and theoretical investigation of formaldehyde (H
2
CO) dissociation to H
2
and CO at energies just above the threshold for competing H elimination. High-resolution state-resolved imaging measurements of the CO velocity distributions reveal two dissociation pathways. The first proceeds through a well-established transition state to produce rotationally excited CO and vibrationally cold H
2
. The second dissociation pathway yields rotationally cold CO in conjunction with highly vibrationally excited H
2
. Quasi-classical trajectory calculations performed on a global potential energy surface for H
2
CO suggest that this second channel represents an intramolecular hydrogen abstraction mechanism: One hydrogen atom explores large regions of the potential energy surface before bonding with the second H atom, bypassing the saddle point entirely.
The Fibrinogen Receptor FbsA Promotes Adherence of
Streptococcus agalactiae
to Human Epithelial Cells
Authors: Schubert Axel , Zakikhany Katherina , Pietrocola Giampiero , Meinke Andreas , Speziale Pietro , Eikmanns Bernhard J. , Reinscheid Dieter J.
Published: October 2004

Streptococcus agalactiae
is a major cause of bacterial pneumonia, sepsis, and meningitis in human neonates. During the course of infection,
S. agalactiae
adheres to a variety of epithelial cells but the underlying mechanisms are only poorly understood. The present report demonstrates the importance of the fibrinogen receptor FbsA for the streptococcal adherence and invasion of epithelial cells. Deletion of the
fbsA
gene in various
S. agalactiae
strains substantially reduced their binding of soluble fibrinogen and their adherence to and invasion of epithelial cells, indicating a role of FbsA in these different processes. The adherence and invasiveness of an
fbsA
deletion mutant were partially restored by reintroducing the
fbsA
gene on an expression vector. Heterologous expression of
fbsA
in
Lactococcus lactis
enabled this bacterium to adhere to but not to invade epithelial cells, suggesting that FbsA is a streptococcal adhesin. Flow cytometry experiments revealed a dose-dependent binding of FbsA to the surface of epithelial cells. Furthermore, tissue culture experiments exhibited an intimate contact of FbsA-coated latex beads with the surfaces of human epithelial cells. Finally, host cell adherence and invasion were significantly blocked in competition experiments with either purified FbsA protein or a monoclonal antibody directed against the fibrinogen-binding epitope of FbsA. Taken together, our studies demonstrate that FbsA promotes the adherence of
S. agalactiae
to epithelial cells but that FbsA does not mediate the bacterial invasion into host cells. Our results also indicate that fibrinogen-binding epitopes within FbsA are involved in the adherence of
S. agalactiae
to epithelial cells.
Regulation ofCandida albicansMorphogenesis by Fatty Acid Metabolites
Authors: Noverr Mairi C. , Huffnagle Gary B.
Published: October 2004

Candida albicansis an opportunistic dimorphic fungus that inhabits various host mucosal sites. Conversion from the yeast to the hyphal form has been associated with increased virulence and mucosal invasiveness.C. albicansmorphogenesis is regulated by multiple signals and signaling pathways. However, signals that control morphogenesis in vivo are unknown. We investigated the effects of host long chain fatty acids, eicosanoids, and bacterial short chain fatty acids on control of germination. None of the C18or C20fatty acids tested had an effect on enhancing germ tube formation (arachidonic acid, oleic acid, linolenic acid, or γ-linolenic acid). Among the different eicosanoids, both prostaglandin E2and thromboxane B2significantly enhanced serum-induced germination byC. albicans. Addition of antiprostaglandin or antithromboxane antibodies to serum alone inhibited germ tube formation by almost 30%, while control antibody had no effect, indicating that these eicosanoids are major morphogenic factors in the serum. Since these molecules also bind to albumin, this may also explain the hyphal transforming activity in serum that associates with albumin. Interestingly, short chain fatty acids (butyric acid), the product of lactic acid bacteria (LAB), inhibited germination. In addition, LAB culture supernatants as well as live LAB also inhibitedC. albicansmorphogenesis. Overall, these results indicate that fatty acid metabolites and fatty acid pathways can up-regulate and down-regulate germination inC. albicans.
Macrophages from Mice with the Restrictive
Lgn1
Allele Exhibit Multifactorial Resistance to
Legionella pneumophila
Authors: Derré Isabelle , Isberg Ralph R.
Published: October 2004

Although
Legionella pneumophila
can multiply in diverse cell types from a variety of species, macrophages from most inbred mouse strains are nonpermissive for intracellular replication and allow little or no growth of the bacteria. This phenomenon is likely genetically controlled by the mouse
naip5
(
birc1e
) gene located within the
Lgn1
locus. In this study, we have investigated the resistance of C57BL/6J macrophages to
L. pneumophila
infection by examining the fate of both the bacterium and the infected cells compared to that in macrophages from the permissive A/J strain. Our results indicate that although the trafficking of the
L. pneumophila
-containing vacuole is partially disrupted in C57BL/6J macrophages, this cannot account for the severity of the defect in intracellular growth observed in this strain. Infected macrophages are lost shortly after infection, and at later times a larger fraction of the C57BL/6J macrophages in which
L. pneumophila
undergoes replication are apoptotic compared to those derived from A/J mice. Finally, a loss of bacterial counts occurs after the first round of growth. Therefore, the resistance mechanism of C57BL/6J macrophages to
L. pneumophila
infection appears to be multifactorial, and we discuss how early and late responses result in clearing the infection.
Cell Wall Mannan and Cell Surface Hydrophobicity in
Candida albicans
Serotype A and B Strains
Authors: Masuoka James , Hazen Kevin C.
Published: October 2004

Cell surface hydrophobicity contributes to the pathogenesis of the opportunistic fungal pathogen
Candida albicans
. Previous work demonstrated a correlation between hydrophobicity status and changes in the acid-labile, phosphodiester-linked β-1,2-oligomannoside components of the N-linked glycans of cell wall mannoprotein. Glycan composition also defines the two major serotypes, A and B, of
C. albicans
strains. Here, we show that the cell surface hydrophobicity of the two serotypes is qualitatively different, suggesting that the serotypes may differ in how they modulate cell surface hydrophobicity status. The cell wall mannoproteins from hydrophilic and hydrophobic cells of both serotypes were compared to determine whether the glycan differences due to serotype affect the glycan differences due to hydrophobicity status. Composition analysis showed that the protein, hexose, and phosphate contents of the mannoprotein fraction did not differ significantly among the strains tested. Electrophoretic profiles of the acid-labile mannan differed only with hydrophobicity status, not serotype, though some strain-specific differences were observed. Furthermore, a newly available β-1,2-oligomannoside ladder allowed unambiguous identification of acid-labile mannan components. Finally, to assess whether the acid-stable mannan also affects cell surface hydrophobicity status, this fraction was fragmented into its component branches by acetolysis. The electrophoretic profiles of the acid-stable branches were very similar regardless of hydrophobicity status. However, differences were observed between serotypes. These results support and extend our current model that modification of the acid-labile β-1,2-oligomannoside chain length but not modification of the acid-stable region is one common mechanism by which switching of cell surface hydrophobicity status of
C. albicans
strains occurs.
SdrX, a Serine-Aspartate Repeat Protein Expressed by
Staphylococcus capitis
with Collagen VI Binding Activity
Authors: Liu Yule , Ames Brenda , Gorovits Elena , Prater Bradley D. , Syribeys Peter , Vernachio John H. , Patti Joseph M.
Published: October 2004

Staphylococcus capitis
(
S. capitis
) has been implicated in a large proportion of coagulase-negative staphylococcal infections in very-low-birth-weight infants. To identify potential therapeutic targets, the
S. capitis
genome was probed for the presence of genes encoding microbial surface components recognizing adhesive matrix molecules (MSCRAMM). By using Southern blot analysis, an
S. capitis
gene, designated
sdrX
, that contained sequence motifs consistent with the Sdr family of MSCRAMM proteins was identified. By using monospecific antisera in Western blot and flow cytometry, SdrX was demonstrated to be expressed on the surface of
S. capitis.
Human collagen type VI was found to bind both the recombinant A domain of SdrX and viable
S. capitis
expressing SdrX. SdrX is the first collagen-binding Sdr protein described and is the first MSCRAMM protein identified in
S. capitis
.
Utility of the
Trypanosoma cruzi
Sequence Database for Identification of Potential Vaccine Candidates by In Silico and In Vitro Screening
Authors: Bhatia Vandanajay , Sinha Mala , Luxon Bruce , Garg Nisha
Published: October 2004

Glycosylphosphatidylinositol (GPI)-anchored proteins are abundantly expressed in the infective and intracellular stages of
Trypanosoma cruzi
and are recognized as antigenic targets by both the humoral and cellular arms of the immune system. Previously, we demonstrated the efficacy of genes encoding GPI-anchored proteins in eliciting partially protective immunity to
T. cruzi
infection and disease, suggesting their utility as vaccine candidates. For the identification of additional vaccine targets, in this study we screened the
T. cruzi
expressed sequence tag (EST) and genomic sequence survey (GSS) databases. By applying a variety of web-based genome-mining tools to the analysis of ∼2,500 sequences, we identified 348 (37.6%) EST and 260 (17.4%) GSS sequences encoding novel parasite-specific proteins. Of these, 19 sequences exhibited the characteristics of secreted and/or membrane-associated GPI proteins. Eight of the selected sequences were amplified to obtain genes
TcG1
,
TcG2
,
TcG3
,
TcG4
,
TcG5
,
TcG6
,
TcG7
, and
TcG8
(
TcG1-TcG8
) which are expressed in different developmental stages of the parasite and conserved in the genome of a variety of
T. cruzi
strains. Flow cytometry confirmed the expression of the antigens encoded by the cloned genes as surface proteins in trypomastigote and/or amastigote stages of
T. cruzi
. When delivered as a DNA vaccine, genes
TcG1-TcG6
elicited a parasite-specific antibody response in mice. Except for
TcG5
, antisera to genes
TcG1-TcG6
exhibited trypanolytic activity against the trypomastigote forms of
T. cruzi
, a property known to correlate with the immune control of
T. cruzi
. Taken together, our results validate the applicability of bioinformatics in genome mining, resulting in the identification of
T. cruzi
membrane-associated proteins that are potential vaccine candidates.
Recognition of Mycobacterial Antigens Delivered by Genetically DetoxifiedBordetella pertussisAdenylate Cyclase by T Cells from Cattle with Bovine Tuberculosis
Authors: Vordermeier H. Martin , Simsova Marcela , Wilkinson Katalin A. , Wilkinson Robert J. , Hewinson R. Glyn , Sebo Peter , Leclerc Claude
Published: October 2004

The exponential increase in the incidence of tuberculosis in cattle over the last two decades in the British national herd constitutes a significant economic problem. Therefore, research efforts are under way to develop cattle tuberculosis vaccines and specific diagnostic reagents to allow the distinction of vaccinated from infected animals. Mycobacterial antigens like ESAT-6 and CFP10 allow this distinction. This study investigates whether fusion protein of ESAT-6 or CFP10 with genetically detoxifiedBordetella pertussisadenylate cyclase (CyaA) are recognized byMycobacterium bovis-infected cattle more effectively than conventional recombinant proteins are, thus enhancing sensitivity or reducing the amount of antigens required. By measuring the frequencies of gamma interferon (IFN-γ)-producing cells, we were able to show that the presentation of CFP10 as a CyaA fusion protein enhanced the molecular efficiency of its recognition 20-fold, while the recognition of ESAT-6 was not improved by CyaA delivery. Furthermore, in the whole-blood IFN-γ test currently used in the field, the delivery of CFP10 and ESAT-6 by fusion to CyaA increased the amount of IFN-γ produced and hence the proportion of infected animals responding to CFP10. The improved T-cell recognition of CyaA336/CFP10 was found to be dependent upon interaction with CD11b. In addition, presentation of CyaA336/CFP10 to CD4+T cells was chloroquine sensitive, and CFP10 delivery by CyaA resulted in its accelerated presentation to T cells. In conclusion, the use of CyaA fusion proteins with ESAT-6 and CFP10 has the potential to improve the sensitivity of immunodiagnostic tests detecting bovine tuberculosis in cattle.