bluuebunny/crossref_metadata_2025 huggingface dataset:
Non‐resective ablation therapy for hepatocellular carcinoma: effectiveness measured by intention‐to‐treat and dropout from liver transplant waiting list
Authors: Fisher RA , Maluf D , Cotterell AH , Stravitz T , Wolfe L , Luketic V , Sterling R , Shiffman M , Posner M
Published: September 2004

Abstract:  Background:  Orthotopic liver transplantation (OLT) for patients with small hepatocellular carcinoma (HCC) is widely accepted, and the usefulness of local ablation techniques as a bridge for liver transplantation is still under investigation.

Methods:  From December 1997 to February 2003, patients with cirrhosis and T0‐T1‐T2‐T3 stage HCC received multi‐modality ablative therapy (MMT) for the treatment of their HCC and were evaluated for OLT; listed, and transplanted when an allograft became available. MMT included radiofrequency ablation (RFA), and/or Trans‐Arterial Chemo‐Embolization (TACE), and alcohol (EtOH) ablation, followed by Trans‐Arterial Chemo‐Infusion (TACI), with repeated treatments based on follow up hepatic magnetic resonance imaging (MRI) during the waiting period for OLT.

Results:  A total of 135 HCC patients were seen at our center within this time frame. The intention‐to‐treat group included 33 (24.4%) patients with T0, T1, T2, T3 HCC and cirrhosis. There were 31 men and two women. The mean age was 53.6 ± 7.2 yr. All patients received MMT with a mean of 2.90 ± 1.5 procedures per patient. Tumor‐node‐metastasis (TNM) stages at time of listing were: T0 in one patient, T1 in nine patients, T2 in 17 patients, and T3 in six patients. Twenty‐eight (85%) patients have received OLT. Five (12.19%) patients were listed and removed (dropout) from the transplant waiting list after waiting 5, 5, 5, 8, and 14 months respectively. The waiting time of the HCC listed group was 9.1 ± 14.8 months with a mean follow up of 32 months. OLT patient survival and cancer‐free survival are 92.9% and 95.24%, respectively; the overall survival of intention‐to‐treat group was 79% at 32 months follow up. Predictors of dropout included an α‐fetoprotein (AFP, >400 ng/mL) and T3 HCC stage.

Conclusion:  Aggressive ablation therapy with a short transplant waiting time optimizes the use of OLT for curative intent in selective cirrhotic HCC patients.
Detection of cardiac allograft rejection by real‐time PCR analysis of circulating mononuclear cells
Authors: Schoels M , Dengler TJ , Richter R , Meuer SC , Giese T
Published: September 2004

Abstract:  Background:  Detection of cardiac allograft rejection is based on the histological examination of endomyocardial biopsies (EMB). We have explored the possibility of whether graft rejection could be detected by characteristic gene expression patterns in peripheral blood mononuclear cells (PBMC) of heart‐transplant recipients.

Methods:  The study included 58 blood samples of 44 patients. On the day of EMB, mononuclear cells were isolated from peripheral blood, and gene expression was measured by quantitative real‐time PCR. Thirty‐nine parameters, including cytokine and chemokine genes were analyzed. Gene expression results were correlated with histological assessment of concomitant evaluated EMB according to International Society for Heart and Lung Transplantation (ISHLT) nomenclature.

Results:  Gene expression of perforin, CD95 ligand, granzyme B, RANTES, CXCR3, COX2, ENA 78 and TGF‐β1 was significantly different in PBMC of patients with mild to moderate degrees of allograft rejection (≥grade 2) compared with patients exhibiting no or minor forms of rejection (<grade 2). Using discriminance analysis, five parameters were found that allow discrimination of rejection ≥grade 2 vs. <grade 2 with a sensitivity of 84% and a specificity of 82% as assessed by receiver operating characteristic analysis.

Conclusion:  Quantitative analysis of gene expression in PBMC may be a valuable tool for non‐invasive diagnosis of allograft rejection and may allow further insight in the biological process of graft rejection.
β6 integrin is up‐regulated in chronic renal allograft dysfunction
Authors: Sawada Tokihiko , Abe Masahiro , Kai Kohtaro , Kubota Keiichi , Fuchinoue Shohei , Teraoka Satoshi
Published: September 2004

Abstract:  Up‐regulation of β6 integrin, which is indispensable to the activation of transforming growth factor‐β1 (TGF‐β1), was investigated in chronic renal allograft dysfunction (CAD). A total of 103 renal biopsy samples (normal, 10; acute rejection, 30; CAD, 63) were immunohistochemically evaluated for expression of TGF‐β1 and β6 integrin. No TGF‐β1 or ‐β6 integrin was detected in normal kidney, but both TGF‐β1 and ‐β6 integrin reactivity were observed in the distal tubules in acute rejection, and even greater reactivity was observed in the distal tubules in the CAD samples. Semiquantitative analysis revealed that the reactivity of TGF‐β1 and ‐β6 integrin was significantly greater in the CAD kidney than in the normal kidney and the kidney in acute rejection. The results suggest that β6 integrin as well as TGF‐β1 is up‐regulated in CAD and that it may serve as an alternative target for the treatment for CAD.
Mycophenolates in transplantation
Authors: Sollinger Hans W
Published: September 2004

Abstract: The discovery of mycophenolic acid (MPA) as a potent immunosuppressant, able to inhibit B‐ and T‐cell proliferation by blocking production of guanosine nucleotides required for DNA synthesis, allowed its potential in the field of transplantation to be realized. Mycophenolate mofetil (MMF), an MPA prodrug, has been shown to be an effective immunosuppressant in transplant therapy. Clinical trials in renal, heart, and liver transplant recipients have demonstrated that, in combination with cyclosporine and steroids, MMF therapy can reduce the incidence and severity of acute rejection episodes and improve graft and patient survival as well as graft function. Although MMF is generally well tolerated, optimal therapy may be limited by associated side effects, in particular gastrointestinal (GI) toxicity, which may occur in over 40% of patients. Dose changes resulting from GI side effects may potentially lead to sub‐therapeutic dosing and impaired clinical outcomes. An enteric‐coated formulation delivering MPA – enteric‐coated mycophenolate sodium (EC‐MPS) has been developed to improve MPA‐related upper GI adverse events. EC‐MPS delays the release of MPA, consistent with a functional enteric‐coating. Recent clinical trials have demonstrated that EC‐MPS is as effective and safe as MMF in bothde novoand maintenance renal transplant patients.
Immunological profile of patients awaiting a renal transplant
Authors: Díaz Inmaculada , Sánchez Pilar , Alonso Clara , Valdés Francisco
Published: September 2004

Abstract: Background: A renal transplant is the best possible treatment for patients with terminal renal failure. Advances in the development of techniques of screening of pre‐formed antibodies have contributed to a notable improvement in the results obtained with allogenic transplants.

Methods: The aim of the present work is to study the nature, class, isotype and specificity of antibodies detected in patients awaiting renal transplantation at Complejo Hospitalario Universitario Juan Canalejo, as well as their relation with the level of anti‐human leucocyte antigen (HLA) sensitization.

Results: In all patient groups, there was a predominance of IgG. The distribution of anti‐HLA antibody class showed that the most frequent pattern corresponded to a mixture of class I and class II antibodies for all groups. The study of specificity of anti‐HLA antibody showed that of the patients with at least one previous transplant, 72% developed specific anti‐HLA antibodies against some of the incompatible antigens of the donor, 12% against HLA antigens not related with the phenotype of the donor and in 16% it was not possible to determine their specificity. Most patients developed antibodies against antigens of locusB, probably because of that the number of incompatibilities contributed by the donors is also greater for locusB.

Conclusions: The exhaustive study of sera of patients on a waiting list for transplantation with respect to the nature, isotype, class and specificity of the antibody is important since it is possible that different antibodies can bring about, in the transplant, events that will have different consequences for the survival of the graft.
T‐cell flow‐cytometry crossmatch and long‐term renal graft survival
Authors: Rebibou JM , Carvalho Bittencourt M , Saint‐Hillier Y , Chabod J , Dupont I , Bittard H , Chalopin JM , Hervé P , Tiberghien P
Published: September 2004

Abstract:  Flow cytometry crossmatch (FCXM) is a more sensitive technique than classical complement‐dependent cytotoxicity (CDC) for the detection of donor‐directed antibody before renal transplantation. Nevertheless, the role of FCXM in predicting long‐term survival of kidney grafts is still unclear. The purpose of our study was to evaluate the impact of a positive T‐cell FCXM (T‐FCXM) on long‐term kidney allografts outcome. Of the 184 consecutive kidney transplantations performed in our center between 1 January1991 and 15 November 1996 a FCXM, performed concurrently to the pre‐transplant CDCXM, was available for 170 patients. The CDCXM was negative in all recipients. Among these recipients, 12 (7.1%) had a positive T‐FCXM. These patients were not different from patients with a negative T‐FCXM for donor and recipient age, sex, frequency of second transplantation, number of human leukocyte antigen matches or mismatches. Frequency of immunized patients was higher in kidney recipients with a positive FCXM (58.3% vs. 24.7%; p = 0.02, chi‐square test). Survival analysis revealed that kidney graft outcome was better in negative T‐FCXM recipients (p = 0.03), while patient survival was not statistically different. Our results suggest that a positive pre‐transplant T‐FCXM despite a negative CDCXM is associated with an impaired long‐term graft survival in renal allotransplantation.
Cytokine mRNA expression in chronically rejected human renal allografts
Authors: Nocera Arcangelo , Tagliamacco Augusto , De Palma Raffaele , Del Galdo Francesco , Ferrante Andrea , Fontana Iris , Barocci Sergio , Ginevri Fabrizio , Rolla Davide , Ravetti Jean Louis , Valente Umberto
Published: September 2004

Abstract:  Although both immunologic and non‐immunologic components may cause kidney allograft chronic rejection (KGCR), also referred to as chronic allograft nephropathy (CAN), its pathogenesis is largely not yet understood. To explore relevant immunologic mechanisms occurring in KGCR, we have analyzed in surgically removed KG the transcription of the following cytokine and apoptotic molecule genes: interleukin (IL)‐2, IL‐3, IL‐4, IL‐5, IL‐6, IL‐10, tumor necrosis factor (TNF)‐α, IFN‐γ, FAS, and FAS‐L. Semiquantitative RT‐PCR was used and KG explants were obtained from two groups of transplanted patients. Group 1 was represented by CR/CAN KG, removed for: (a) superimposed symptoms of acute lesions (SAL) due to tapering or suspension of immunosuppression (subgroup 1a, eight cases); (b) causes other than SAL (two cases, subgroup 1b). Group 2 comprised explanted kidneys with no CR/CAN (three cases – vascular thrombosis, intrarenal hemorrhage and vascular thrombosis). The results showed that in group 1 IL‐ 6 was detectable in seven of 10, IL‐10 in six of 10, IFN‐γ in five of 10, and IL‐3 in four of 10 cases with a variable pattern of reciprocal association. IL‐2 and TNF‐α were represented in one of 10 cases only. Particularly, in the subgroup 1b IL‐10 was never detected. Among the most represented cytokines of group 1, IL‐10 as well as IL‐3 were never found in group 2. The peculiar expression of IL‐10 and IL‐3 and partially IL‐6 seems to support the hypothesis that a Th2 pattern predominantly characterizes KGCR, thus indicating that Th2 cytokines, likely produced by different intragraft cell types including T cells, macrophages and natural killer (NK) cells, may represent an important component in the pathogenesis of this process. Moreover, IL‐10 seems to exquisitely characterize a group of CR/CAN kidney grafts more prone to immunologic assaults.
Long‐term follow‐up of pediatric transplant recipients: mycophenolic acid trough levels are not a good indicator for long‐term graft function
Authors: Pape L , Ehrich JHH , Offner G
Published: September 2004

Abstract:  Background:  Mycophenolate mofetil (MMF) has the potential of decreasing acute rejection episodes early following renal transplantation. Pharmocokinetic monitoring of mycophenolic acid (MPA) trough levels is performed by many centers. MMF has also proved successful in improving long‐term graft function in patients with chronic allograft nephropathy (CAN). However, no data for long‐term monitoring of MPA in children have yet been published.

Methods:  MMF therapy with a dose of 600 mg/m2 twice daily was initiated in 42 children (median age 9.4 yr, range 1.4–15.1) after a median period of 3.8 yr (range 1.0–10.6) post‐transplantation – according to significant increases in serum creatinine. CAN was diagnosed by renal biopsy and the amount of fibrosis was quantified with PicroSiriusRed staining. MMF therapy was combined with ciclosporin A and prednisolone. MPA‐C0‐levels, measured by high‐pressure liquid chromatography, were tested every 3 months. In 12 children a full MPA area under the curve concentration (AUC) was measured. The glomerular filtration rate (GFR) was calculated at the start of MMF therapy and 2 yr later.

Results:  After initiation of MMF, the calculated GFR did not decrease further in 22 children and mean GFR remained stable for 2 yr in the whole study group. There was a significant correlation between MPA levels 75 min after administration and the full AUC (r = 0.94, p < 0.001) but no correlation between trough levels and AUC (r = −0.07, p > 0.05). The mean MPA trough level was 2.8 ± 1.3 ng/mL. The intra‐individual coefficient of variation was 2.6 ± 1.4. There was no correlation between mean MPA trough levels and GFR development after 2 yr (r = 0.03, p > 0.05). In children with an MPA level below 1.2 mg/L (n = 5), the mean GFR decline was no different to those with a higher level (p > 0.05).

Conclusions:  Drug monitoring of MPA trough levels had no impact on long‐term graft function in kidney recipients. MPA levels taken 75 min after administration showed a high correlation with MPA‐AUC whereas C0‐levels did not correlate. The value of C75 drug measurements for monitoring renal allograft survival will have to be judged in future studies.
Endoscopic diagnosis of cytomegalovirus infection of upper gastrointestinal tract in solid organ transplant recipients: Hungarian single‐center experience
Authors: Péter Antal , Telkes Gábor , Varga Marina , Sárváry Enik˝ , Kovalszky Ilona
Published: September 2004

Abstract: Background: Cytomegalovirus (CMV) is considered to be the major cause of upper gastrointestinal (GI) symptoms in organ transplant recipients. In the diagnosis of GI CMV infection the detection of the virus in the mucosa is essential. The aim of the study was to evaluate the significance of CMV, detected in biopsy specimens from stomach and duodenum of solid organ transplant recipients.

Methods: Data of 227 elective upper endoscopies on symptomatic organ transplant recipients were evaluated for clinical symptoms, endoscopic changes and conventional histologic alterations of mucosal biopsy samples. Qualitative PCR was performed for detection of the presence of CMV‐DNA in each biopsy materials.

Results: CMV‐DNA was detected in biopsy samples of 91 patients (40.1%) while only in 20 cases (8.8%) the signs of CMV infections were found by conventional histology (p < 0.00001). No considerable differences could be observed in symptomatic, histologic alterations between CMV‐PCR positive and negative groups. There were no endoscopic changes in 25.3% of CMV‐PCR positive and 5.1% of negative patients.

Conclusions: Qualitative PCR is an accurate method for the detection of CMV in the mucosa of the GI tract. Further investigations are needed for determination of the exact pathological role of detected CMV.
Severe elevations of FK506 blood concentration due to diarrhea in renal transplant recipients
Authors: Sato Koichiro , Amada Noritoshi , Sato Takaomi , Miura Shunji , Ohashi Yoichi , Sekiguchi Satoshi , Satomi Susumu , Okazaki Hajime
Published: September 2004

Abstract:  Background:  The rate of metabolism in the intestine of oral administered FK506 decreases as FK506 passes on to the lower intestine. In transplant recipients with diarrhea given oral FK506, the main areas for absorption of FK506 shift to the lower intestine, where the ability to metabolize FK506 is weaker. Therefore it is considered likely that when FK506 is administered to recipients with diarrhea, the blood concentration of FK506 will be higher.

Material and Methods:  Twenty recipients experiencing episodes of diarrhea were investigated to determine the trough level of FK506 and the time required for the FK506 trough level to return to the level that obtained before diarrhea. AUC0−4h and Cmax of FK506 were investigated in eight recipients. In cases with severe diarrhea, the daily fluctuations of FK506 blood concentration were also investigated.

Result:  The FK506 trough level (p < 0.0001), AUC (p = 0.0173), and Cmax (p = 0.0173) were found to be significantly higher during episodes of diarrhea. In almost all cases, it took between 2 and 4 wk for the elevated FK506 trough level to return to its previous level following a bout of diarrhea. In the daily fluctuations of FK506 concentration, Tmax was prolonged. In some cases, the concentration was highest just before administration of FK506, when it should have been at trough level.

Conclusions:  Diarrhea caused significant elevations of trough level, AUC0−4h and Cmax of FK506, and the prolongation of Tmax in renal transplant recipients administered FK506.
Cardiovascular disease in stable renal transplant patients in Norway: morbidity and mortality during a 5‐yr follow‐up
Authors: Aakhus Svend , Dahl Ketil , Widerøe Tor Erik
Published: September 2004

Abstract:  Background:  Although cardiovascular disease is a major cause of death after renal transplantation (Tx), predictors for cardiovascular events have not been well defined. Aims of this cross‐sectional study were first to assess cardiovascular morbidity and mortality in stable renal Tx patients, and to identify predictors for cardiovascular events during long‐term follow‐up.

Methods:  In all, 406 renal Tx patients (mean age: 47 yr, 60.1% males, 70.9% using cyclosporine A) commenced a baseline registration (median) 48 months after Tx, and 405 was thereafter followed in 5 yr. Kaplan–Meier plots and multivariate regression analysis (Cox proportional hazards model) were used to identify and characterize predictors for cardiovascular events.

Results:  There were 88 deaths (average annual mortality: 4.4%), and 74% of these were cardiovascular. In age groups 40–49, 50–59, and 60–69 yr, odds ratio for cardiovascular mortality in patients vs. general population was 46.2, 20.1, and 8.0, respectively. Death from ischemic heart disease (IHD) was independently predicted by baseline congestive heart failure (relative risk: RR 5.33), diabetes (RR 2.28), systolic blood pressure (mmHg, RR 1.02), age (yr, RR 1.06), and high‐density lipoprotein cholesterol (mmol/L, RR 0.36). Predictors for a major ischemic heart event (death from or onset of IHD) were in addition baseline total cholesterol (mmol/L, RR 1.18) and cerebrovascular disease (RR 2.98).

Conclusions:  Thus, IHD was the major cause of death late after renal Tx, and a major ischemic heart event was predicted by baseline congestive heart failure, diabetes, age, hypertension, and hypercholesterolemia.
Feasibility of sputum induction in lung transplant recipients
Authors: Van Den Berg Jan WK , Slebos Dirk‐Jan , Postma Dirkje S , Dijkhuizen Brigitte , Koëter Gerard H , Timens Wim , Van Bij Wim der , Kauffman Henk F
Published: September 2004

Abstract:  Sputum induction (SI) is nowadays being applied as a non‐invasive and safe method to investigate airway inflammation in pulmonary diseases. We investigated the feasibility of SI after lung transplantation (LTX), and compared sputum and bronchoalveolar lavage (BAL) cellular characteristics and interleukin‐8 (IL‐8) levels. Results were also compared with 11 healthy subjects. SI as performed between 26 and 1947 d after LTX in 19 recipients, was successful in 16 of 22 attempts (73%). Six patients failed to produce sputum after induction, mostly just post‐LTX and with having a lower forced expiratory volume in 1 s (FEV1). The success rate in clinically stable patients after the first month post‐LTX was 93%. Side‐effects were absent. Sputum recovery, viability and squamous cell contamination were comparable between LTX patients and healthy subjects. In the LTX group, total cell counts, neutrophil percentages and IL‐8 levels were much higher in SI than BAL (1.6 × 106/mL, 65.5% and 54.2 ng/mL vs. 0.1 × 106/mL, 3.0% and 0.01 ng/mL; p < 0.001). Although LTX‐neutrophil percentages in SI and BAL correlated properly (ρ = 0.72, p = 0.04), both techniques are not interchangeable. We conclude that sputum induction is feasible, well tolerated, and without major side‐effects in stable patients after the first month post‐LTX. Induced sputum may be a useful tool to study inflammatory changes of the airways after LTX, and because of the large quantity of neutrophils sampled, especially for further studies on the pathogenesis of bronchiolitis obliterans.
The Maintenance of Stable Dominance Hierarchies and the Pattern of Aggression: Support for the Suppression Hypothesis
Authors: Forkman B. , Haskell M. J.
Published: September 2004

Three hypotheses have been proposed to explain the development and maintenance of dominance hierarchies. According to the first hypothesis the dominance hierarchy is a result of the animals fighting once at their first encounter and then using the outcome of that fight to determine the rank order. The second hypothesis proposes that a dominance hierarchy reflects the fighting ability of the individuals in the group at each moment and is therefore relatively fluid with individuals continuously fighting for position. A third hypothesis, the suppression hypothesis, states that the dominance hierarchy is based to a large extent on the outcome of the first fight between the individuals but the dominant animal in each pair continuously attacks the subdominant individuals to condition them to lose in future encounters. We studied six well‐established flocks containing six adult hens each (Gallus gallus domesticus). Five of the flocks had linear hierarchies. The aggression was significantly more often directed towards the next low‐ranking individual. There was a good correlation between rank and comb size (height × width), but no significant correlation between rank and weight, or rank and level of fluctuating asymmetry. There was no significant correlation between levels of aggression and similarity of comb size for individuals of neighboring ranks. Our results tentatively support the suppression hypothesis for the maintenance of dominance hierarchies in the domestic hen.
Winter Plumage Coloration in Male American Goldfinches: Do Reduced Ornaments Serve Signaling Functions in the Non‐Breeding Season?
Authors: McGraw Kevin J.
Published: September 2004

The signaling role of sexual ornaments that are displayed during the mating season is well known for many species, but dimorphisms that occur in the non‐breeding season have received much less attention, particularly when individuals only partially express their breeding condition during reproductively inactive periods. I assessed variation in the expression of colorful breeding and non‐breeding plumages in male American goldfinches (Carduelis tristis), a species in which males molt out of their colorful breeding ornaments in the fall but still display reduced carotenoid‐ and melanin‐based sexual dichromatism during the winter. I found that variability in the saturation of carotenoid‐based plumage pigmentation did not differ significantly between the breeding and non‐breeding seasons. Moreover, the area of melanin coloration in the cap was more variable in winter than when it is fully displayed during breeding. I also detected a significant positive correlation between the extent of melanin coloration during the winter and the saturation of non‐breeding carotenoid‐based plumage. Because of such variation in and correlated expression of these two color ornaments in winter, it is conceivable that male goldfinches display these hints of non‐breeding coloration for use as conspecific social or sexual signals. Natural selection pressures like predation and energetic demands are traditionally thought of as factors that restrict sex ornaments to breeding times alone, but this should not preclude animals from simply reducing their exaggerated features during winter and finding an expression optimum that balances signal costs and value. Such ‘remnant’ winter ornaments might be expected to evolve not only in animals that live in large non‐breeding groups (e.g. status‐signaling systems) but also in those where mates begin associating before breeding onset.
Approach Strategy by which Male Mediterranean Tarantulas Adjust to the Cannibalistic Behaviour of Females
Authors: Moya‐Laraño Jordi , Pascual Jordi , Wise David H.
Published: September 2004

In sexually cannibalistic species, selection is thought to have favoured the evolution of male approaching behaviour that reduces the probability that the female will kill the male. However, investigations of behaviours that could reduce the probability of sexual cannibalism are few. We examine the hypothesis that male wolf spiders,Lycosa tarantula(L.) (Araneae, Lycosidae), decides to approach females in periods when they are less dangerous. Males of this species approach females for mating during the daytime only. While attending females, males stay farther from the female's burrow at night than during the daytime. In field experiments, we offered a grasshopper (typical prey) or a maleL. tarantulato females at night and during the day, and our findings show that the diel changes in the male's approaching behaviour matches diurnal changes in the female's tendency to attack both the grasshopper and the male spider. These findings support our hypothesis that a diel change in female responsiveness to prey has been a selection pressure influencing the evolution of male approach behaviour in a sexually cannibalistic species.
Multicentre analysis of treatment planning information: Technical requirements, possible applications and a proposal
Authors: Ebert MA , Blight J , Price S , Haworth A , Hamilton C , Cornes D , Joseph DJ
Published: September 2004

Digital data from 3‐D treatment planning computers is generally used for patient planning and then never considered again. However, such data contains enormous quantities of information regarding patient geometries, tissue outlining, treatment approaches and dose distributions. Were such data accessible from planning systems from multiple manufacturers, there would be substantial opportunities for undertaking quality assurance of radiotherapy clinical trials, prospective assessment of trial outcomes and basic treatment planning research and development. The technicalities of data exchange between planning systems are outlined, and previous attempts at producing systems capable of viewing and/or manipulating imaging and radiotherapy digital data reviewed. Development of a software system for enhancing the quality of Australasian clinical trials is proposed.
Functional mapping of GABAA receptor subtypes in the amygdala
Authors: Marowsky Anne , Fritschy Jean‐Marc , Vogt Kaspar E.
Published: September 2004

The physiological significance of the large diversity of GABAA receptors is poorly understood. Using mice, which carry a point mutation that renders specific subtypes of GABAA receptors diazepam insensitive, it was recently discovered that particular types of GABAA receptors are involved in specific, behaviorally relevant signaling pathways. We have used these mice to study inhibitory synaptic transmission in the amygdala. GABAA receptor‐mediated inhibitory postsynaptic currents (IPSCs) per se were not affected by the point mutations. Their modulation by diazepam, however, was altered depending on the genotype of the mice studied. Based on the different responses to diazepam, we found that IPSCs in the lateral/basolateral amygdala were mediated by both α2‐ and α1‐subunit‐containing GABAA receptors whereas those in the central amygdala were mediated only by α2‐subunit‐containing GABAA receptors. Immunohistochemical staining corroborated these findings at a morphological level. To investigate a possible link between interneuron and receptor diversity, we selectively depressed release from the subset of GABAergic terminals carrying type 1 cannabinoid receptors. These receptors are known to modulate amygdala‐mediated behavior. Application of a type 1 cannabinoid receptor agonist resulted in a selective reduction of inhibitory current mediated by α1‐subunit‐containing GABAA receptors. Mice with specific diazepam‐insensitive GABAA receptor subtypes therefore provide a novel tool to investigate GABAA receptor distribution and the organization of inhibitory circuits at a functional level. The crucial role of the amygdala for the mediation of anxiety is in agreement with the part that α2‐subunit‐containing GABAA receptors play in anxiolysis and their important function in this area of the brain.
Endogenous acetylcholine lowers the threshold for long‐term potentiation induction in the CA1 area through muscarinic receptor activation: in vivo study
Authors: Ovsepian Saak V. , Anwyl Roger , Rowan Michael J.
Published: September 2004

Little is known how synaptically released endogenous ACh affects hippocampal synaptic plasticity in vivo. Here, we examined the role of cholinergic drive in the regulation of the induction of long‐term potentiation (LTP) at basal dendrites in the CA1 area of the anaesthetized rat hippocampus. The non‐subtype selective muscarinic acetylcholine receptor antagonist, scopolamine, (0.3 mg/kg, i.p.) inhibited the induction of LTP by weak, but not strong, high frequency conditioning stimulation. A relatively M1 subtype‐selective receptor antagonist, pirenzepine, (50 nmol/5 µL, i.c.v.) also inhibited LTP induction by the weak protocol. As the medial septum (MS) is a major source of endogenous ACh in the hippocampus, we also examined the effect of high frequency pre‐conditioning stimulation of the MS on LTP induction. The pre‐conditioning MS tetanus reduced the threshold for LTP induction at basal synapses in a narrow time window. Such an effect of MS pre‐conditioning was prevented by scopolamine, strong evidence of a direct MS control of LTP threshold through a mechanism dependent on muscarinic receptor activation. These results suggest that the cholinergic drive to the hippocampus is critically involved in the control of the LTP induction threshold in vivo. To the extent that LTP mechanisms may underlie certain types of learning and memory, the septo‐hippocampal cholinergic regulation of synaptic plasticity may constitute an important target for the treatment of cognitive disorders associated with ACh deficits.
Regional pattern of metabolic activation is reflected in the sleep EEG after sleep deprivation combined with unilateral whisker stimulation in mice
Authors: Vyazovskiy Vladyslav V. , Welker Egbert , Fritschy Jean‐Marc , Tobler Irene
Published: September 2004

Regional differences in EEG slow wave activity (SWA) during sleep after sleep deprivation (SD) may be a consequence of differential metabolic activation of cortical areas. We investigated the relationship between the regional EEG dynamics and 2‐deoxyglucose (DG) uptake after SD in mice. Six hours' SD were combined with natural unilateral whisker stimulation in an enriched environment to selectively activate the barrel cortex and motor areas. As expected, an interhemispheric asymmetry of 2‐DG uptake was found in the barrel cortex immediately after SD. To test whether sleep contributes to recovery of the asymmetry, the stimulation was followed by either undisturbed sleep or by an additional SD. The asymmetry vanished after recovery sleep but also after the additional period of wakefulness without stimulation. In addition, relative 2‐DG uptake in the primary motor cortex and retrosplenial area was significantly higher immediately after the SD than after the additional sleep or wakefulness, whereas no other region differed between the groups. Whisker stimulation elicited a greater increase in EEG SWA during non rapid eye movement sleep in the stimulated hemisphere than in the control hemisphere; this increase lasted for 10 h. Within a hemisphere, the initial increase in SWA was higher in the frontal than in the parietal derivation. We conclude that the regional SWA differences during sleep are use‐dependent and may be related to the regional pattern of metabolism during the previous waking episode. However, the regional metabolic recovery is not dependent on sleep, and is not directly reflected in changes in SWA during sleep.
Attention and executive function deficits in chronic low‐dose MPTP‐treated non‐human primates
Authors: Decamp E. , Schneider J. S.
Published: September 2004

Parkinson's disease (PD) is a complex disorder consisting of motor deficits coupled with dysfunction in cognitive domains that are dependent upon the integrity of the frontal lobes and/or the fronto‐striatal axis. Although it is increasingly acknowledged that PD patients have attentional and executive function deficits, it has been difficult to model these in nonhuman primates because of the nature of the cognitive tasks that have been used previously. The present studies were conducted to further define the nature of the cognitive impairment in a nonhuman primate model of early parkinsonism consequent to chronic low dose MPTP exposure and to further validate this model in monkeys trained to perform a battery of attentional and executive function tasks. Following chronic low dose MPTP exposure, monkeys developed deficits in maintenance of a response set as well problems in shifting attentional sets, suggesting decreased mental flexibility. On other tasks inattentiveness, an impaired ability to sustain spatial attention or to focus attention, a deficit in motor readiness and planning, and impaired time estimation were also observed. These results provide direct evidence of attention and executive function deficits in a nonhuman primate model of early parkinsonism. Based on these findings, we suggest that in addition to being useful for studying the cognitive deficits related to early PD and for developing new therapeutics for these problems, this model and these testing procedures may also provide a useful large animal model for studying attention deficit disorder and for developing new therapeutics for that condition as well.
An evolutionarily conserved mechanism for sensitization of soluble guanylyl cyclase reveals extensive nitric oxide‐mediated upregulation of cyclic GMP in insect brain
Authors: Ott Swidbert R. , Delago Antonia , Elphick Maurice R.
Published: September 2004

Soluble guanylyl cyclase (SGC) is the main receptor for the gaseous signalling molecule nitric oxide (NO) in vertebrates and invertebrates. Recently, a novel class of drugs that regulate mammalian SGC by NO‐independent allosteric mechanisms has been identified [e.g. 3‐(5′‐hydroxymethyl‐2′‐furyl)‐1‐benzyl indazole, YC‐1]. To assess the evolutionary conservation and hence the potential physiological relevance of these mechanisms, we have tested YC‐1 on the brains of two model insects, the cockroach Periplaneta americana and the locust Schistocerca gregaria. YC‐1 strongly potentiated the NO‐induced elevation of total cyclic 3′,5′‐guanosine monophosphate (cGMP) and amplified the intensity and consistency of NO‐induced cGMP‐immunoreactivity in the brain. Our data indicate that the effect of YC‐1 was independent of phosphodiesterase inhibition and thus mediated by direct sensitization of SGC. Immunohistopharmacology and co‐labelling with antibodies against the SGC α‐subunit confirmed that cGMP induced by co‐application of NO and YC‐1 is predominantly attributable to SGC. The staggering number of NO‐responsive neurons revealed by YC‐1 suggests that previous studies may have considerably underestimated the number of cellular targets for NO in the insect brain. Moreover, a subset of these targets exhibited cGMP‐immunoreactivity without application of exogenous NO, demonstrating that YC‐1 can be exploited for visualization of physiological cGMP signals in response to endogenous NO production. In conclusion, our discovery that YC‐1 is a potent sensitizer of insect SGC indicates that a NO‐independent regulatory site is an evolutionarily conserved feature of SGC. Our findings add considerable momentum to the concept of an as yet unidentified endogenous ligand that regulates the gain of the NO–cGMP signalling pathway.
Neural contributions to the motivational control of appetite in humans
Authors: Hinton Elanor C. , Parkinson John A. , Holland Anthony J. , Arana F. Sergio , C. Roberts Angela , Owen Adrian M.
Published: September 2004

The motivation to eat in humans is a complex process influenced by intrinsic mechanisms relating to the hunger and satiety cascade, and extrinsic mechanisms based on the appetitive incentive value of individual foods, which can themselves induce desire. This study was designed to investigate the neural basis of these two factors contributing to the control of motivation to eat within the same experimental design using positron emission tomography. Using a novel counterbalanced approach, participants were scanned in two separate sessions, once after fasting and once after food intake, in which they imagined themselves in a restaurant and considered a number of items on a menu, and were asked to choose their most preferred. All items were tailored to each individual and varied in their incentive value. No actual foods were presented. In response to a hungry state, increased activation was shown in the hypothalamus, amygdala and insula cortex as predicted, as well as the medulla, striatum and anterior cingulate cortex. Satiety, in contrast, was associated with increased activation in the lateral orbitofrontal and temporal cortex. Only activity in the vicinity of the amygdala and orbitofrontal cortex was observed in response to the processing of extrinsic appetitive incentive information. These results suggest that the contributions of intrinsic homeostatic influences, and extrinsic incentive factors to the motivation to eat, are somewhat dissociable neurally, with areas of convergence in the amygdala and orbitofrontal cortex. The findings of this study have implications for research into the underlying mechanisms of eating disorders.
Activation of group I metabotropic glutamate receptors enhances efficacy of glutamatergic inputs to neonatal rat hypoglossal motoneurons in vitro
Authors: Sharifullina Elina , Ostroumov Konstantin , Nistri Andrea
Published: September 2004

Group I metabotropic glutamate receptors (mGluRs) are the main class of metabotropic receptors expressed in the hypoglossus nucleus. Their role in glutamatergic transmission was investigated using patch‐clamp recording from motoneurons in a neonatal rat brainstem slice preparation. After pharmacological block of γ‐aminobutyric acid and glycine‐mediated inhibition, under voltage‐clamp, the selective group I agonist (RS)‐3,5‐dihydroxyphenylglycine (DHPG) induced a motoneuron inward current by depressing a leak conductance, and strongly facilitated spontaneous glutamatergic synaptic currents. This effect was blocked by 7‐(hydroxyimino)cyclopropa[b]chromen‐1a‐carboxylate ethyl ester (CPCCOEt) and unaffected by 2‐methyl‐6‐(phenylethynyl)pyridine hydrochloride (MPEP), indicating a role for subtype 1 mGluRs. The frequency but not the amplitude of miniature glutamatergic currents was also enhanced by DHPG. Currents elicited by puffer application of (RS)‐α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) in the presence of tetrodotoxin were also unchanged, suggesting that DHPG facilitated release of glutamate. Glutamatergic currents evoked by electrically stimulating the dorsomedullary reticular column premotoneurons were, however, depressed by DHPG in a CPCCOEt‐sensitive fashion. Neither CPCCOEt nor MPEP per se changed glutamatergic transmission. Under current‐clamp, even if DHPG depressed excitatory postsynaptic potentials, motoneuron spike threshold and time to peak were reduced so that facilitation of synaptic potential/spike coupling became apparent. We propose a wiring diagram to account for the differential action by DHPG on spontaneous and evoked transmission, based on the discrete distribution of subtype 1 mGluRs on glutamatergic afferents. Although under standard recording conditions there was insufficient ambient glutamate to activate mGluRs, such receptors were a powerful target to upregulate excitatory synaptic transmission and enhance signalling by hypoglossal motoneurons to tongue muscles.
Chronic l‐DOPA treatment increases extracellular glutamate levels and GLT1 expression in the basal ganglia in a rat model of Parkinson's disease
Authors: Robelet S. , Melon C. , Guillet B. , Salin P. , Kerkerian‐Le Goff L.
Published: September 2004

There is growing experimental evidence for the implication of glutamate‐mediated mechanisms both in the pathophysiology of Parkinson's disease and in the development of dyskinesias with long‐term administration of l‐3,4‐dihydroxyphenylalanine (l‐DOPA). However, the impact of this treatment on glutamate transmission in the basal ganglia has been poorly investigated. In this study, we examined the effects of 6‐hydroxydopamine‐induced lesion of nigral dopamine neurons with or without subsequent chronic l‐DOPA treatment on several parameters of glutamate system function in the rat striatum and substantia nigra pars reticulata. All the lesioned animals treated with l‐DOPA developed severe dyskinesias. Extracellular glutamate levels, measured by microdialysis in freely moving conditions, and gene expression of the glial glutamate transporter GLT1, assessed by in situ hybridization, were unaffected by dopamine lesion or l‐DOPA treatment alone, but were both markedly increased on the lesion side of rats with subsequent l‐DOPA treatment. No change in the expression of the vesicular glutamate transporters vGluT1 and vGluT2 was measured in striatum. These data show that chronic l‐DOPA treatment leading to dyskinesias increases basal levels of glutamate function in basal ganglia. The l‐DOPA‐induced overexpression of GLT1 may represent a compensatory mechanism involving astrocytes to limit glutamate overactivity and subsequent toxic processes.
Corticostriatal brain‐derived neurotrophic factor dysregulation in adult rats following prenatal stress
Authors: Fumagalli Fabio , Bedogni Francesco , Perez Jorge , Racagni Giorgio , Riva Marco Andrea
Published: September 2004

Prenatal stress represents a well‐established experimental protocol resembling some features of schizophrenia, including deficits in social interactions, disruption of prepulse inhibition and enhanced response to psychomotor stimulants. In order to evaluate molecular changes that could participate in long‐lasting effects on brain function, we analysed the effects of prenatal stress on the expression of brain‐derived neurotrophic factor (BDNF), an important molecular determinant of synaptic plasticity and cellular homeostasis, in adult male rats under basal conditions as well as in response to a chronic stress. The main finding is that BDNF expression is reduced in the prefrontal cortex and striatum of prenatally stressed rats. Furthermore, when exposed to chronic stress in adulthood, these rats display an altered regulation of BDNF expression in these brain structures, implying that adverse life events during gestation may interfere with the expression and function of this neurotrophin at adulthood in a region‐specific manner. The dysregulation of corticostriatal BDNF expression might thus contribute to permanent alterations in brain functions leading to heightened susceptibility to psychiatric disorders.
Contribution of GABAergic inhibition to synaptic responses and LTD early in postnatal development in the rat superior colliculus
Authors: Mize R. Ranney , Salt Thomas E.
Published: September 2004

We studied the development of optic tract evoked field potentials (FP) in the rodent superior colliculus (SC) and the effect of GABA antagonists upon their development and upon induction of long‐term depression (LTD). Brain slices were cut from Lister Hooded rats. The optic tract was stimulated while recording from the superficial grey layer. GABAergic inhibition was assessed by adding 100 µm picrotoxin and 3 µm CGP55845 antagonists to block GABAA,B,C receptors. LTD was induced with a 50 Hz, 20 s tetanus. At age P2, the FP consisted only of a presynaptic spike. The GABA antagonists had no effect. By P4, the FP consisted of a presynaptic spike, a longer latency population spike, and a field excitatory postsynaptic potential (fEPSP). The fEPSP was slightly prolonged by the GABA antagonists at this age. By P7–P14, a prominent FP with trailing fEPSP was recorded. The GABA antagonists usually had a large effect, with the fEPSP increasing in both amplitude and duration. A mature FP was usually recorded in P15–P23 slices where the GABA antagonist effect remained substantial. LTD could be induced in 17 of 30 control slices from rats aged P4–P26. The average fEPSP amplitude after tetanus was 77.9% of control. Pre‐treatment with GABA antagonists produced a short‐term potentiation (average 114.0%), rather than LTD, in 14 of 19 cases. This STP was followed by a more prolonged potentiation in 12 of the 14 cases. We conclude that GABAergic inhibitory circuits mature before eye opening and that GABA contributes to induction of LTD in the developing SC.
Peripubertal environmental enrichment reverses the effects of maternal care on hippocampal development and glutamate receptor subunit expression
Authors: Bredy Timothy W. , Zhang Tie Yuan , Grant Rebecca J. , Diorio Josie , Meaney Michael J.
Published: September 2004

Maternal care in the rat influences the development of cognitive function in the offspring through neural systems known to mediate activity‐dependent synaptic plasticity. The offspring of mothers that exhibit increased levels of pup licking/grooming (high‐LG mothers) show increased hippocampal N‐methyl‐d‐aspartate (NMDA) subunit mRNA expression, enhanced synaptogenesis and improved hippocampal‐dependent spatial learning in comparison with animals reared by low‐LG mothers. The effects of reduced maternal care on cognitive function are reversed with peripubertal environmental enrichment; however, the neural mechanisms mediating this effect are not known. In these studies we exposed the offspring of high‐ and low‐LG mothers to environmental enrichment from days 22 to 70 of life, and measured the expression of genes encoding for glutamate receptor subunits and synaptophysin expression as a measure of synaptic density. Environmental enrichment reversed the effects of maternal care on synaptic density and this effect was, in turn, associated with a reversal of the effect of maternal care on the NR2A and NR2B subunits of the NMDA receptor, as well as effects on (RS)‐α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) receptor subunits. Finally, direct infusion of an NR2B‐specific NMDA receptor antagonist into the hippocampus eliminated the effects of maternal care on spatial learning/memory in the Morris water maze. These findings suggest that: (1) the effects of maternal care are mediated by changes in NR2B gene expression; and (2) that environmental enrichment reverses the effects of reduced maternal care through the same genomic target, the NR2B gene, and possibly effects on other subunits of the NMDA and AMPA receptors.