bluuebunny/crossref_metadata_2025 huggingface dataset:
Phylogenetic systematics of Pseudolebinthus, a new genus of Eneopterinae crickets (Orthoptera, Grylloidea, Eneopteridae) from south‐east Africa
Authors: ROBILLARD TONY
Published: October 2006

Abstract Within a framework of historical analysis of Eneopterinae crickets, the genus Pseudolebinthus Robillard gen.n. and two new species P. africanus Robillard, sp.n. and P. whellani Robillard, sp.n., endemic from south‐east Africa, are described. A cladistic analysis using 198 morphological characters and 47 terminals assessed the phylogenetic position of the new taxa within the subfamily. The resultant topologies support the previously proposed phylogeny for the subfamily and contained tribes. The monophyly of Pseudolebinthus is supported strongly as well as its sister relationship with Xenogryllus within the tribe Xenogryllini. A key to Eneopterinae tribes, Xenogryllini genera and Pseudolebinthus species is given. Taxonomic, evolutionary and acoustic issues raised by the recognition of Pseudolebinthus are discussed.
Proteinuria in pediatric renal transplant recipients during the first 60 post‐transplant days
Authors: Chua Annabelle N , Alexander Steven R , Sarwal Minnie M , Millan Maria , Salvatierra Oscar , Yorgin Peter D.
Published: October 2006

Abstract:  Although normative values of post‐transplant proteinuria have been reported in adults, data for pediatric renal transplant recipients have not been previously published. We hypothesized that pediatric renal transplant recipients achieve normal urinary protein to creatinine (UProt/UCr) ratios (<0.2) by 60 days post‐transplant in the absence of early recurrent disease. Retrospective chart review of 108 consecutive pediatric renal transplant recipients at Stanford University was performed. Thirty‐two (30%) patients who were eligible had ≥1 UProt/UCr ratio obtained during the first 60 post‐transplant days. Mean age at transplant was 13.9 ± 4.2 yr. UProt/UCr ratios were grouped by week post‐transplant for quantile analysis. Mean weekly UProt/UCr values were not lower than 0.2 until the ninth post‐transplant week. No difference in post‐transplant proteinuria existed between nephrectomized and non‐nephrectomized transplant recipients. Experience with a single patient with proven focal segmental glomerulosclerosis (FSGS) recurrence suggests that normative UProt/UCr data may be useful in early identification of patients experiencing disease recurrence. Univariate correlations demonstrated that UProt/UCr negatively correlated with serum albumin levels (−0.415, p < 0.0001) and days post‐transplant (−0.531, p < 0.0001). Independent of primary diagnosis, proteinuria persists throughout the first 60 days in most pediatric renal transplant patients, decreasing relative to time post‐transplant.
Expert pediatric opinion on the Report of the Baveno IV Consensus Workshop on Methodology of Diagnosis and Therapy in Portal Hypertension
Authors: Shneider Benjamin , Emre Sukru , Groszmann Roberto , Karani John , McKiernan Patrick , Sarin Shiv , Shashidhar Harohalli , Squires Robert , Superina Riccardo , De Ville de Goyet Jean , De Franchis Roberto
Published: October 2006

Abstract:  Portal hypertension leads to a wide variety of complications, which lead to significant morbidity and mortality and are some of the leading reasons for liver transplantation in children with chronic liver disease. Evidence‐based approaches to the management of adults with portal hypertension exist and have been comprehensively reviewed in a series of international meetings, including the Baveno meetings. Similar evidence‐based approaches for the management of portal hypertension in children do not exist and as such international meetings on portal hypertension have not focused on this problem in children. On October 7, 2005 at The Mount Sinai School of Medicine, a panel of pediatric experts reviewed the most recent Baveno statement and crafted a statement modified with their opinions vis a vis approaches to the management of portal hypertension in children.
Hematopoietic stem cell transplantation for Diamond‐Blackfan anemia: A report from the Aplastic Anemia Committee of the Japanese Society of Pediatric Hematology
Authors: Mugishima H. , Ohga S. , Ohara A. , Kojima S. , Fujisawa K. , Tsukimoto I. ,   for the Aplastic Anemia Committee of the Japanese Society of Pediatric Hematology
Published: October 2006

Abstract:  Transfusion‐dependent Diamond‐Blackfan anemia (DBA) patients opt for allogeneic hematopoietic stem cell transplantation (HSCT) as curative therapy. Clinical outcomes of 19 transplanted Japanese patients were analyzed. Prior to HSCT, 10 patients (53%) suffered hemosiderosis with organ dysfunction, and all eight with short stature (42%) had adverse effects of prednisolone. Median age at the time of HSCT was 56 months. Transplantation sources were 13 bone marrow [six human leukocyte antigen (HLA)‐matched siblings, and six HLA‐matched and one HLA‐mismatched unrelated donors], five cord blood (two HLA‐matched siblings and three HLA‐mismatched unrelated donors), and one peripheral blood from haploidentical mother. All 13 patients with bone marrow transplantation (BMT) and two with sibling cord blood transplantation (CBT) had successful engraftment. Of three patients who underwent unrelated CBT, one died after engraftment, and the other two had graft failure but succeeded in a second BMT from an HLA‐disparate father and unrelated donor, respectively. One died shortly after haploidentical PBSCT. The five‐yr failure‐free survival rate after BMT was higher than CBT (100%: 40%, p = 0.002). Platelet recovery was slower in seven unrelated BMT than in six sibling BMT (p = 0.030). No other factors were associated with engraftment and survival. These results suggest that allogeneic BMT, but not unrelated CBT, is an effective HSCT for refractory DBA.
Intravenous immunoglobulin, HLA allele typing and HLAMatchmaker facilitate successful transplantation in highly sensitized pediatric renal allograft recipients
Authors: Valentini Rudolph P. , Nehlsen‐Cannarella Sandra L. , Gruber Scott A. , Mattoo Tej K. , West Miguel S. , Lang Cheryl , Imam Abubakr A.
Published: October 2006

Abstract:  The use of intravenous immunoglobulin (IVIG) in sensitized transplant candidates has resulted in reduced HLA antibody levels and shorter transplant wait times. In addition, the HLAMatchmaker program has been used to identify acceptable mismatches to permit transplantation in highly sensitized patients. We used IVIG desensitization in conjunction with high resolution HLA allele typing and HLAMatchmaker grading of donor offers to facilitate successful transplantation in two highly sensitized children who were awaiting second renal transplants. Both patients lost their initial transplant in <10 days to accelerated acute rejection, and were on dialysis for an average of 50 months with high panel reactive antibody (PRA) levels. They were started on monthly IVIG infusions (2 g/kg/dose). Within one wk following their third and fifth IVIG doses, both patients received a crossmatch compatible, deceased donor renal transplant selected by HLAMatchmaker as a suitable donor offer. Both patients remain rejection free with excellent renal function 19 and 15 months post‐transplant, respectively. In conclusion, combining IVIG therapy and donor selection by HLA humoral epitope matching permitted successful transplantation of two highly sensitized children. Further studies in larger numbers of patients with longer follow‐up are needed to determine the individual role played by, and relative importance of each component of this combined strategy.
Neurological complications of liver transplantation in pediatric patients: A single center experience
Authors: Erol Ilknur , Alehan Füsun , Ozcay Figen , Canan Oguz , Haberal Mehmet
Published: October 2006

Abstract:  Neurologic complications (NCs) are a significant cause of morbidity and mortality in patients who undergo liver transplantation (LT). The aim of this study was to evaluate the incidence and type of NCs and associated factors in pediatric LT patients. We retrospectively reviewed NCs in the medical records of 40 consecutive infants, children, and adolescents who underwent LT at our institution. The subjects consisted of 23 boys and 17 girls (median age, 8.5 ± 0.85 yr; range, 11 months to 17 yr). The indications for LT were Wilson's disease in 10 patients, fulminant hepatic failure (FHF) in nine, and other types of chronic liver disease in 21. NCs were found in 14 patients (35%). Those 14 individuals experienced a total of 16 episodes of NCs (two separate episodes in two of the patients). The most common NCs were seizure (seven episodes in six patients) and posterior leukoencephalopathy syndrome (PLES; five episodes in four patients). Seizure was the presenting symptom in three episodes of PLES. Two episodes of diffuse encephalopathy were observed in two patients, and two episodes of psychiatric symptoms occurred in two patients. We also noted one episode of tremor in one patient, one episode of acute dystonic reaction in one patient, and one episode of headache in one patient. Patients with Wilson's disease had a higher incidence of NCs (60%) than did patients without Wilson's disease (26.7%); however, this difference was not significant. The incidence of NCs was 44% in patients with FHF and 35% in those without FHF. That difference also was not significant. Immunosuppressive agents were the primary cause of 13 of the 16 episodes of NC. Uremia with hypertension, hypoxia, and hypomagnesemia caused one neurologic episode each. NCs, which are frequent in the first 30 days after pediatric LT, did not affect survival in this group. NCs were reversed by the discontinuation or reduction of immunosuppressive agents in 12 episodes, correction of hypomagnesemia and the reduction of immunosuppressive agents in one episode, and the correction of uremia and hypertension in one episode. Refractory epilepsy developed in one patient, and death unrelated to NCs occurred in one. The mortality rate was 7.1% (n = 1) in patients with NCs and 15.4% (n = 4) in those without NCs (p = 0.64). NCs are an important complication after LT. It is essential that each transplantation team collaborate with pediatric neurologists to ensure the rapid and accurate diagnosis of NCs in infants, children, and adolescents after LT and to prevent the delay of appropriate treatment.
FURTHERING INJUSTICES AGAINST WOMEN: GENETIC INFORMATION, MORAL OBLIGATIONS, AND GENDER
Authors: DE MELO‐MARTÍN INMACULADA
Published: October 2006

The purpose of this paper is to show that a decontextualized approach to ethical issues is not just unhelpful for the decision making process of real, situated human beings, but dangerous. This is so, because by neglecting the context in which people make moral decisions we run the risk of reinforcing or furthering injustices against already disadvantaged groups. To show this, I evaluate three moral obligations that our ability to obtain genetic information has made salient: the duty to obtain genetic information about ourselves, the obligation to inform family members about genetic risks and the duty not to reproduce when we know that there is a high risk of transmitting a serious disease or defect. I will argue here that in ignoring the context in which these moral obligations are put into practice, and in particular the situation of women in our society, those who defend these moral duties might be furthering injustices against women.
The Nexus of Corporate Entrepreneurship and Radical Innovation
Authors: Lassen Astrid Heidemann , Gertsen Frank , Riis Jens Ove
Published: October 2006

This paper explores the linkage between the entrepreneurial orientation of established firms and the development of radical innovation. Through five case studies in firms involved in radical innovation, three propositions are developed, suggesting that proactiveness, risk‐taking and autonomy stimulate the development of radical innovation, whereas competitive aggressiveness does not necessarily do so, as radical innovations are directed towards the creation of entirely new arenas of business, where existing competitors are not present.
The development of adopted children after institutional care: a follow‐up study
Authors: Vorria Panayiota , Papaligoura Zaira , Sarafidou Jasmin , Kopakaki Maria , Dunn Judy , Van IJzendoorn Marinus H. , Kontopoulou Antigoni
Published: October 2006

Background:  Research suggests that institutional care has long‐lasting effects on children. However, no study has longitudinally studied infants in an institution and their subsequent development at age four.

Methods:  Sixty‐one adopted children aged four years who had spent their first two years of life in an institution were compared to 39 children reared in their own two‐parent families. Cognitive development, security of attachment, shyness, children's emotional understanding and behavioural problems were examined in both groups. Parental health and stress were also assessed

Results:  At four years adopted children still had lower scores on cognitive development, were less secure, and less able to understand emotions than family‐reared children. Children with a secure attachment type in infancy were found to be less secure at age four, compared with those who were classified in infancy as having an insecure attachment type. Their physical development had recovered, they were less shy, had no behavioural problems and no problems in the relationship with their teacher.

Conclusions:  Early residential group care has long‐lasting effects on important socio‐emotional and cognitive aspects of preschool children's development.
The impact of alcohol‐specific rules, parental norms about early drinking and parental alcohol use on adolescents’ drinking behavior
Authors: Van Der Vorst Haske , Engels Rutger C.M.E. , Meeus Wim , Deković Maja
Published: October 2006

Background:  The present study explores the role of having rules about alcohol, parental norms about early alcohol use, and parental alcohol use in the development of adolescents’ drinking behavior. It is assumed that parental norms and alcohol use affect the rules parents have about alcohol, which in turn prevents alcohol use by adolescent children.

Methods:  Longitudinal data collected from 416 families consisting of both parents and two adolescents (aged 13 to 16 years) were used for the analyses.

Results:  Results of structural equation modeling show that having clear rules decreases the likelihood of drinking in adolescence. However, longitudinally alcohol‐specific rules have only an indirect effect on adolescents’ alcohol use, namely through earlier drinking. Analyses focusing on explaining the onset of drinking revealed that having strict rules was related to the postponement of drinking initiation of older and younger adolescents. Further, parental norms about adolescents’ early drinking and parental alcohol use were associated with having alcohol‐specific rules. Parental norms were also related to adolescents’ alcohol use.

Conclusions:  The current study is one of the first using a full family design to provide insight into the role of alcohol‐specific rules on adolescents’ drinking. It was shown that having strict rules is related to postponement of drinking, and that having alcohol‐specific rules depends on other factors, thus underlining the complexity of the influence of parenting on the development of adolescents’ alcohol use.
Triiodothyronine‐Induced Shortening of Chromatin Repeat Length in Neurons Cultured in a Chemically Denned Medium
Authors: Cestelli Alessandro , Di Liegro Italia , Castiglia Daniele , Gristina Roberto , Ferraro Donatella , Salemi Giuseppe , Savettieri Giovanni
Published: October 2006

Abstract: At the time of terminal differentiation, mammalian cortical neurons undergo a dramatic change in the structural organization of their chromatin: the nucleosomal repeat length shortens from ∼200 base pairs in fetuses to a value of 165 base pairs after birth. These events occur several days after the end of neuronal proliferation. Previously, we reported that rat cortical neurons cultured in a very selective synthetic medium were not yet programmed to these events at the end of mitotic cycles. Herein, we report that addition of triiodothyronine to neuronal cultures induces a shortening of the chromatin repeat length comparable to the natural one.
Subcellular Location and Neuronal Release of Diazepam Binding Inhibitor
Authors: Ferrarese Carlo , Vaccarino Flora , Alho Hannu , Mellstrom Britt , Costa Erminio , Guidotti Alessandro
Published: October 2006

Abstract: Diazepam binding inhibitor (DBI), a peptide located in CNS neurons, blocks the binding of benzodiaze‐pines and β‐carbolines to the allosteric modulatory sites of γ‐aminobutyric acid (GABAA) receptors. Subcellular frac‐tionation studies of rat brain indicate that DBI is compartmentalized. DBI‐like immunoreactivity is highly enriched in synaptosomes obtained by differential centrifugation in isotonic sucrose followed by a Percoll gradient. In synapto‐somal lysate, DBI‐like immunoreactivity is primarily associated with synaptic vesicles partially purified by differential centrifugation and continuous sucrose gradient. Depolarization induced by high K+ levels (50 mM) or veratridine (50 μM) released DBI stored in neurons of superfused slices of hypothalamus, hippocampus, striatum, and cerebral cortex. The high K+ level‐induced release is Ca2+ dependent, and the release induced by veratridine is blocked by 1.7 μM tetrodotoxin. Depolarization released GABA and Met5‐enkephalin‐Arg6‐Phe7 together with DBI. DBI is also released by veratridine depolarization, in a tetrodotoxin‐sen‐sitive fashion, from primary cultures of cerebral cortical neurons, but not from cortical astrocytes. Depolarization fails to release DBI from slices of liver and other peripheral organs. These data support the view that DBI may be released as a putative neuromodulatory substance from rat brain neurons.
Selective Inhibition of Synaptosomal γ‐Aminobutyric Acid Uptake by Triethyllead: Role of Energy Transduction and Chloride Ion
Authors: Seidman Brenda C. , Verity M. Anthony
Published: October 2006

Abstract: Triethyllead (TEL) is a CNS neurotoxin producing bizarre neurobehavioral changes. The principal objective of this study was to determine if TEL‐induced defects in energy metabolism were responsible for the inhibition of synaptosomal Na+‐dependent high‐affinity uptake of γ‐aminobutyric acid (GABA). A dose‐dependent inhibition of GAB A uptake (ID50= 10 μMTEL) was found during 30‐s incubations. Uptake of glutamate was more resistant to the inhibitory effects of TEL. A TEL‐induced Cl− ‐dependent synaptosomal deficit of ATP was observed. Such deficit in high‐energy phosphate was time‐dependent and did not occur in the absence of Cl− or as early as 30 s. Inhibition of GABA uptake, on the other hand, was a Cl−‐independent phenomenon and was observed at as early as 30 s. TEL was not competitive with Na+ or GABA itself, as the effects of TEL were not overcome with high [Na+] or [GABA]. These results indicate that the locus of TEL inhibition of GABA uptake is not a Cl−‐dependent event and does not involve a perturbed transmembrane electrochemical gradient, due to either an observed mitochondrial defect or an inhibition of Na+, K+‐ATPase directly.
Guanine Nucleotide and Cation Regulation of μ, δ, and k Opioid Receptor Binding: Evidence for Differential Postnatal Development in Rat Brain
Authors: Szöcs Mária , Spain James W. , Oetting Gregory M. , Moudy Anna M. , Coscia Carmine J.
Published: October 2006

Abstract: A study of the onset of cation and guanine nucleotide regulation of δ, μ, and k rat brain opioid receptors during postnatal development was undertaken. Site‐specific binding assays were utilized for each receptor type and the effects of 0.5 mM MnCl2, 100 mM NaCl, and/or 50 μM guanosine‐5′‐(β,γ‐imido) triphosphate [GPP(NH)P] were assessed. The most pronounced changes of opioid binding were seen in the presence of Mn2+. In adults, agonist binding to δ sites was stimulated by Mn2+, whereas that to μ. sites was not affected and k binding was inhibited. The postnatal development of Mn2+ regulation for the three receptor subtypes was distinctly different. The largest effects were seen on δ sites detected in the early neonatal period, Mn2+ eliciting a 68% stimulation of binding over controls at day 1. Significant inhibition of k site binding by Mn2+ was detected only after the third postnatal week. Mn2+ caused a significant reversal of Gpp(NH)p inhibition of δ binding in the early neonatal period, exceeding that in the absence of regulators. Inhibition of μ and δ receptor binding by Na+ was greater, and the Mn2+ reversal of this effect was smaller, in the first 2 postnatal weeks than in adults. Gpp(NH)p + Na+ regulation did not change appreciably during the postnatal period. However, Mn2+ reversal of the considerable inhibition elicited by the combination of Na+ and Gpp(HN)p was developmental time‐dependent. The data are discussed in terms of multiple sites of interaction for guanine nucleotides and cations. Our results demonstrate that the characteristics and postnatal development of guanine nucleotide and cat‐ionic regulation of μ, δ, and k binding are distinctly different. Furthermore, neonates may serve as a model for the examination of individual regulatory effects on opioid receptors.
l‐Phenylalanyl‐l‐Glutamate‐Stimulated, Chloride‐Dependent Glutamate Binding Represents Glutamate Sequestration Mediated by an Exchange System
Authors: Kessler Markus , Petersen Gene , Vu Hai Minh , Baudry Michel , Lynch Gary
Published: October 2006

Abstract: Stimulation of glutamate binding by the dipeptide l‐phenylalanyl‐l‐glutamate (Phe‐Glu) was inhibited by the peptidase inhibitor bestatin, suggesting that the stimulation was caused by glutamate liberated from the dipeptide and not by the dipeptide itself. It further suggests that this form of glutamate binding should be reinterpreted as glutamate sequestration and that stimulation of binding both by dipeptides and after preincubation with high concentrations of glutamate is likely to be due to counterflow accumulation. Several other criteria indicate that most of glutamate binding stimulated by chloride represents glutamate sequestration: Binding is reduced when the osmolarity of the incubation medium is increased, when membranes incubated with [3H]glutamate are lysed before filtration, and when membranes are made permeable by transient exposure to saponin. Moreover, dissociation of bound glutamate after a 100‐fold dilution of the incubation medium is accelerated about 50 times by the addition of glutamate to the dilution medium. This result would be anomalous if glutamate were bound to a receptor site; it suggests instead that glutamate is transported in and out of membrane vesicles by a transport system that preferentially mediates exchange between internal and external glutamate. Glutamate binding contains a component of glutamate sequestration even when measured in the absence of chloride. Sequestration is adequately abolished only after treating membranes with detergents; even extensive lysis, sonication, and freezing/thawing may be insufficient.
Delta Sleep‐Inducing Peptide Modulates the Stimulation of Rat Pineal N‐Acetyltransferase Activity by Involving the α1 ‐Adrenergic Receptor
Authors: Graf Markus V. , Schoenenberger Guido A.
Published: October 2006

Abstract: Delta sleep‐inducing peptide (DSIP) has been isolated and characterized by its capacity to enhance delta sleep in rabbits. Up to now, sleep was the main target of DSIP research, but different extra‐sleep effects of the peptide have been reported as well. Several mechanisms of action have been proposed, though no convincing evidence for any of them has been obtained so far. We recently detected that DSIP reduced the nocturnal increase of N‐acetyltransferase (NAT) activity in rat pineal in a dose‐dependent manner. The activity of this enzyme is known to be induced by adrenergic agonists and several studies have suggested that stimulation of α1‐adrenergic receptors potentiates the “basic” effect of β‐receptors. DSIP in the range between 20 and 300 nM significantly enhanced NAT activity induced by 10‐6M norepinephrine in vitro, and a similar effect was observed with 2 nM P‐DSIP, a phosphorylated analog. Incubation with prazosin eliminated the enhancement, whereas propranolol reduced norepinephrine stimulation that was still increased by P‐DSIP and probably DSIP. It was concluded that the sleep‐peptide and its analog modulate the α1‐adrenergic receptor of rat pineal in its response to adrenergic agonists. The same mechanism may also be responsible for other biological activities of DSIP such as sleep‐induction and stress‐tolerance.
Development of Sodium Channel Protein During Chemically Induced Differentiation of Neuroblastoma Cells
Authors: Baumgold Jesse , Spector Ilan
Published: October 2006

Abstract: We have previously shown that the [3H]saxitoxin binding site of the sodium channel is expressed independently of the [125I]scorpion toxin binding site in chick muscle cultures and in rat brain. In the present work, we studied the development of the sodium channel protein during chemically induced differentiation of N1E‐115 neuroblastoma cells, using [3H]saxitoxin binding, [125I]scorpion toxin binding, and 22Na uptake techniques. When grown in their normal culture medium, these cells are mostly undifferen‐tiated, bind 90 ± 10 fmol of [3H]saxitoxin/mg of protein and 112 ± 14 fmol of [125I]scorpion toxin/mg protein, and, when stimulated with scorpion toxin and batrachotoxin, take up 70 ± 5 nmol of 22Na/min/mg of protein. Cells treated with dimethyl sulfoxide (DMSO) or hexamethy‐lene‐bis‐acetamide (HMBA) differentiate morphologically within 3 days. At this time, the [3H]saxitoxin binding, the [125I]scorpion toxin binding, and the 22Na uptake values are not very different from those of undifferentiated cells. With subsequent time in DMSO or HMBA, these values continue to increase, a result indicating that the main period of sodium channel expression occurs well after the cells have assumed the morphologically differentiated state. The data indicate that the expression of sodium channels and morphological differentiation are independently regulated neuronal properties, that the attainment of morphological differentiation is necessary but not in itself sufficient for full expression of the sodium channel proteins, and that, in contrast to the chick muscle cultures and rat brain, the [3H]saxitoxin site and [125I]scorpion toxin site appear to be coregulated in N1E‐115 cells.
Enhancement of γ‐Aminobutyric Acid Binding by the Anxiolytic β‐Carbolines ZK 93423 and ZK 91296
Authors: Corda M. G. , Giorgi O. , Longoni B. , Mereu G. P. , Biggio G.
Published: October 2006

Abstract: The effects of two anxiolytic β‐carboline derivatives, ZK 93423 and ZK 91296, on the binding of γ‐[3H]aminobutyric acid ([3H]GABA) to brain membrane preparations from rat cerebral cortex were examined. ZK 93423 concentration‐dependently enhanced the specific binding of [3H]GABA, with a maximal increase of 45% above control at a 50 μM concentration. A less pronounced increase was induced by diazepam and by the partial agonist ZK 91296. Scatchard plot analysis revealed that the effect of ZK 93423 was due to an increase in the total number of high‐ and low‐affinity GABA binding sites. The action of ZK 93423 was mediated by benzodiazepine recognition sites since it was blocked by the benzodiazepine antagonists Ro 15–1788 and ZK 93426 at concentrations that failed to modify [3H]GABA binding on their own. Moreover the stimulatory effect of ZK 93423 on [3H]GABA binding was also blocked by the β‐carboline inverse agonist ethyl β‐carboline‐3‐carboxylate. These results are consistent with the view that ZK 93423 and ZK 91296, similarly to benzodiaze‐pines, exert their pharmacological effects by enhancing the GABAergic transmission at the level of the GABA/benzodiazepine receptor complex.
Inhibition of M and P Phenol Sulfotransferase by Analogues of 3′‐Phosphoadenosine‐5′‐Phosphosulfate
Authors: Rens‐Domiano Stephanie S. , Roth Jerome A.
Published: October 2006

Abstract: Structural analogues of the sulfate donor 3′‐phosphoadenosine‐5′‐phosphosulfate (3′,5′‐PAPS) were examined for their ability to inhibit dopamine and phenol sulfation by the M and P forms of phenol sulfotransferase (PST), respectively. The Ki values for each of the adenosine derivatives were calculated from the rate equation for PST. For both M and P PST, the naturally occurring product 3′‐phosphoadenosine‐5′‐phosphate, (3′,5′‐PAP), was shown to be the most effective inhibitor. The weakest inhibitors of the two sulfotransferases were 5′‐adenosine phosphosulfate and the three AMP derivatives, which were <1,000 times as effective as 3′,5′‐PAP. 5′‐ATP, 2′,5′‐PAPS, 2′,5′‐PAP, and 5′‐ADP were similar in their inhibition of M and P PST and were all ∼ 100 times less effective than the natural end product. These data reveal that there is a rigid structural requirement for binding of the ribose portion of adenosine to both M and P PST that involves the groups on both the 3′ and 5′ positions. The effectiveness of binding to the two enzymes may depend on both steric factors as well as the distribution of negative charges on the ribose ring.
Both Short‐ and Long‐Term Effects of Nerve Growth Factor on Tyrosine Hydroxylase in Calf Adrenal Chromaffin Cells Are Blocked by S‐Adenosylhomocysteine Hydrolase Inhibitors
Authors: Acheson Ann , Thoenen Hans
Published: October 2006

Abstract: We have previously shown that primary cultures of calf chromaffin cells respond to nerve growth factor (NGF) treatment with a selective induction of tyrosine hydroxylase (TH), which takes 48 h to be manifested. In the present study, we report that short exposure of calf chromaffin cells to NGF (5–60 min) results in TH activation, which involves a change in the Fmax of the enzyme with no change in the number of enzyme molecules, similar to an effect that has been previously reported in PC 12 cells. This activation is markedly potentiated when the chromaffin cells are plated on a laminin substrate, such that after 5 min of NGF exposure, there is an approximately fourfold increase in the TH activity. Both short‐term activation and long‐term TH induction brought about by NGF treatment are blocked by 5′‐deoxy‐5′‐methylthioadenosine and other drugs that act as S‐adenosylhomocysteine (SAH) hydrolase inhibitors to block methylation by end‐product inhibition. These drugs did not inhibit cyclic AMP‐mediated TH activation or increases in the levels of TH. However, measurements of the degree of blockade of methylation in cells treated with these drugs, taken together with conceptual information regarding the nonregulatory nature of methylation in eukaryotic cells, were not consistent with inhibition of methylation as the crucial effect of the drugs to block the effects of NGF. Nonetheless, since SAH hydrolase inhibitors selectively inhibited NGF‐mediated effects, and not comparable effects triggered by other stimuli, these compounds provide useful tools in future studies of the biochemical signalling mechanism of NGF.
Characterization and Partial Purification of a Novel Neuronotrophic Factor from Bovine Seminal Vesicle
Authors: Hofmann Hans‐Dieter , Unsicker Klaus
Published: October 2006

Abstract: Extracts from bovine seminal vesicles have been shown to contain high concentrations of nerve growth factor (NGF)‐like biological activity and of the NGF protein with properties corresponding to that of NGF from other sources. We now demonstrate that a second neuronotrophic protein, termed seminal vesicle‐derived neuronotrophic factor (SVNF), is present in seminal vesicle extracts (SVEs), which could not be distinguished from NGF on the basis of biological activity. SVNF has neuronotrophic activity on NGF target cells like embryonic chicken sensory and sympathetic neurons, sympathetic neurons, and chromaffin cells from neonatal rats, but it is inactive on embryonic chicken ciliary or neonatal rat nodose ganglion neurons. It also stimulates fiber outgrowth from rat pheochromocytoma (PC 12) cells. In gel filtration chromatography on Biogel A 1.5 m, the activity is eluted with an apparent molecular weight of 40 kilodaltons, and by preparative isoelectric focusing, the isoelectric point was determined to be in the neutral range (6.8–7.8).The biological activity of SVNF, in contrast to that of NGF, is partially retained after preparative sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and can be electrophoretically eluted with an apparent molecular weight of 16–20 kilodaltons. Electrophoretically purified SVNF is not inhibited by antisera to mouse NGF, but its activity is increased > 10–fold in the presence of very low concentrations of NGF. For partially purified SVNF, a specific activity of 2.9–5.8 × 105 biological units/mg of protein was determined in the presence of subthreshold NGF concentrations. Thus, two neuronotrophic proteins, SVNF and NGF, are present in high amounts in extracts from bovine seminal vesicles, exhibit very similar and cooperative biological activities, but differ in molecular weights, isoelectric point, and immunological properties.
Muscarinic Mobilization of Choline in Rat Brain In Vivo as Shown by the Cerebral Arterio‐Venous Difference of Choline
Authors: Brehm Rudolf , Lindmar Ruth , Löffelholz Konrad
Published: October 2006

Abstract: In anesthetized rats, the choline levels of cerebrospinal fluid and plasma obtained from blood collected from peripheral vessels (carotid artery, cardiac vessels) and from the transverse sinus were determined with a radioenzymatic assay. Cortical release of choline was studied using the “cup technique.” The plasma choline level of the peripheral blood (11.5 μmol/L) was lower than that of the sinus blood. The resulting cerebral arterio‐venous difference of choline was negative (3.2 μmol/L) and reflected the net release of choline from the whole brain. The plasma choline levels were not different irrespective of whether the rats were anesthetized with ether, urethane, or pentobarbital. However, the choline level of the cerebrospinal fluid, which normally was lower than the plasma choline levels, was increased by urethane anesthesia to a level between the arterial and venous plasma concentrations of the brain. In old rats (24 months), the choline level of the cerebrospinal fluid was significantly lowered, when compared with the results obtained with younger rats (2–4 months). In rats kept on a low‐choline diet for 2 weeks, the plasma choline level of the peripheral blood was reduced to 51% of the control. The effect on the choline level of the sinus blood was smaller; the cerebral arterio‐venous difference of choline was not reduced (it was even slightly enhanced). Likewise, the cholinelevel of the cerebrospinal fluid and the cortical release of choline were not altered. Intraperitoneal administration of oxotremorine in pentobarbital‐anesthetized rats kept on a low‐choline diet increased the plasma levels of choline. The rise of the plasma level of the peripheral blood was blocked by atropine and by methylatropine. Atropine alone or in combination with oxotremorine reduced the arterio‐venous difference to half the level obtained by oxotremorine or oxotremorine plus methylatropine. In conclusion, the net formation of choline in the whole brain is partially controlled by central cholinergic activity and is unaltered even at a considerably reduced supply of choline from the peripheral circulation. Moreover, the remarkable maintenance of a certain choline level of the cerebrospinal fluid at a reduced (low‐choline diet) or elevated (oxotremorine) plasma level also suggests that the extracellular concentration of choline in the brain is held at a constant level eventually at the expense of cellular phospholipids.
entaaification of Atrial Natriuretic Factor Receptor of Neuroblastoma N4TG1 Cells: Binding Characteristics and Photoaffinity Labeling
Authors: Pandey Kailash N. , Misono Kunio S. , Takayanagi Ryoichi , Pavlou Spyros N. , Inagami Tadashi
Published: October 2006

Abstracts

We have found specific receptors for atrial natriuretic factor (ANF) in cultured neuroblastoma cells (N4TG1) of peripheral ganglionic origin. Scatchard analysis of the displacement binding revealed noninteracting, singleclass binding sites with a KD of 1 ± 1010M and a density (Bmax) of 110,000–150,000 sites/cell. The cell‐bound 125I‐ANF was displaced by unlabeled ANF in a dose‐dependent manner. Hormones unrelated to ANF such as angiotensins, adrenocorticotropic hormone, or arginine vasopressin were ineffective in displacing the cell‐bound radioactivity. Using azidobenzoyl‐125I‐ANF as a photoaffinity ligand, an ANF receptor with an apparent Mr of 138,000 was identified by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and autoradiography. The addition of unlabeled ANF (1 μM) to the incubation medium completely abolished the labeling of this protein band, but atriopeptin I (1 μM) or angiotensins I, II, and III (each 1 μM) were not effective in inhibiting the affinity labeling. The treatment of the neuroblastoma cells with ANF stimulated intracellular cyclic GMP levels in a dose‐dependent manner with an EC50 of 5 nM. ANF(1 ± 107M) stimulated cyclic GMP accumulation in <5 min by 30‐fold as compared to the controls.
Effects of Polyhydroxyl Alcohols on Protein Synthesis in Brain Slices
Authors: White F. P. , White S. R.
Published: October 2006

Abstract: Stressors such as tissue slicing, toxic chemicals, and heat shock applied to cultured cells, organ tissues, or whole animals in vivo induce the synthesis of a 71,000‐kilodalton stress protein (SP71) that is not normally present in most organ tissues. In the present experiment, an attempt was made to inhibit selectively the synthesis of SP71 in rat brain tissue slices. Of several manipulations to the brain slice incubation medium that were examined, only addition of very high concentrations of certain polyhydroxyl alcohols, i.e., 1.0 M glycerol, selectively inhibited SP71 synthesis. Glycerol also selectively inhibited SP71 synthesis in heat‐shocked cerebral microvascular cells in culture but failed to inhibit SP71 synthesis in anesthetized rats in vivo in response to heat shock. The effects of glycerol on SP71 synthesis are discussed in relationship to current hypotheses concerning the function of SP71.
Characterization of Fucosyl Oligosaccharides Associated with Synaptic Membrane and Synaptic Junctional Glycoproteins
Authors: Stanojev Dawn , Gurd James W.
Published: October 2006

Abstract: Rats were administered [3H]fucose by intracranial injection and synaptic membranes (SMs) isolated 18 h later. Oligosaccharides associated with SM glycoproteins were prepared by hydrazinolysis and analyzed by a combination of affinity chromatography on concanavalin A (Con A)‐agarose, ion‐exchange chromatography on DEAE‐celluiose, and gel permeation chromatography. Most (94%) of the [3H]fucose‐labelled oligosaccharides were present in the fraction that did not bind to Con A. Of these 41% did not bind to DEAE‐cellulose, indicating the absence of negatively charged groups and the remainder were resolved into four fractions of increasing acidity. Gel permeation chromatography of the fractions from the DEAE‐cellulose column suggested that the major oligosaccharides corresponded to fucosylated triantennary structures containing varying amounts of sialic acid although more highly branched structures containing peripheral branches lacking one or more sugars may also have been present. Comparison of fucosyl oligosaccharides associated with SMs prepared from 10‐ and 28‐day‐old animals indicated that although the general oligosaccharide content was similar at both ages, membranes from younger animals were characterized by an increase in the proportion of highly acidic structures. Fucosylated glycans derived from synaptic junctional (SJ) glycoproteins were also characterized by a greater percentage of highly acidic structures than SMs. The results indicate that SMs and SJs are characterized by specific complements of fucosylated glycoprotein oligosaccharides.
Effects of Heavy Metal Cations and Other Sulfhydryl Reagents on Brain Dopamine D1 Receptors: Evidence for Involvement of a Thiol Group in the Conformation of the Active Site
Authors: Braestrup Claus , Andersen Peter H.
Published: October 2006

Abstract: To investigate aspects of the biochemical nature of membrane‐bound dopamine D1 receptors, rat striatal homogenates were pretreated with heavy metal cations and some other chemical agents, and their effects on D1 receptors were subsequently determined using a standard [3H]CR)‐(+)‐8‐chloro‐2,3,4,5‐tetrahydro‐3‐methyl‐5‐phenyl‐1‐N‐3‐benzazepine ([3H]SCH 23390) binding assay. Incubation of striatal membranes with as little as 1 μM Hg2+, 10 μM Cu2+, and 10 μM Cd2+ completely prevented specific [3H]SCH 23390 binding. The effect of Cu2+, 1.5 μM was noncompetitive in nature, whereas 3‐5 μM Cu2+ afforded mixed‐type inhibition. The inhibitory effect of Cu2+ was fully reversed by dithiothreitol (0.1‐1 mM). Cu2+ (2 μM) did not affect the affinity of m‐flupenthixol or clo‐zapine for remaining [3H]SCH 23390 sites. A second series of cations, Co2+ (30 μM), Ni2+ (30 μM), Mn2+ (1 mM), Ca2+ (25 mM), and Ba2+ (20 mM), inhibited specific [3H]SCH 23390 binding by 50% at the concentrations indicated. The thiol alkylating reagent N‐ethylmaleimide (NEM) (0.2 mM) reduced specific binding by 70%. The effect of NEM was completely prevented by coincubation with a D1 receptor saturating concentration of SCH 23390 (20 nM) or dopamine (10 μM). The results indicated that the dopamine D1 receptor is a thiol protein and that a thiol group is essential for the ligand binding.
Specificity of Ethylcholine Mustard Aziridinium as an Irreversible Inhibitor of Choline Transport in Cholinergic and Noncholinergic Tissue
Authors: Uney J. B. , Marchbanks R. M.
Published: October 2006

Abstract: The sensitivity of choline transport to inhibition by ethylcholine mustard aziridinium (ECMA) was studied in several tissues. Choline transport was found to be inhibited irreversibly by ECMA in guinea pig and rat synapto‐somes but not inhibited in erythrocytes or kidney slices. If this finding can be extended to other tissues ECMA sensitivity may provide a simple criterion for identifying the choline carrier associated with cholinergic tissue.
Characterization of the Binding of [3H]SR 95531, a GABAA Antagonist, to Rat Brain Membranes
Authors: Heaulme Michel , Chambon Jean‐Pierre , Leyris Roger , Wermuth Camille G. , Biziere Kathleen
Published: October 2006

A synthetic derivative of γ‐aminobutyric acid (GABA), SR 95531 [2‐(3′‐carboxy‐2′‐propyl)‐3‐amino‐6‐p‐methoxyphenylpyridazinium bromide], has recently been reported, on the basis of biochemical and in vivo microion‐tophoretic studies, to be a potent, selective, competitive, and reversible GABAA antagonist. In the present study, the binding of [3H]SR 95531 to washed, frozen, and thawed rat brain membranes was characterized. Specific binding was linear with tissue concentrations, had a pH optimum at neutrality, and was maximal at 4°C after 30 min of incubation. Pretreatment of the membranes with Triton X‐100 resulted in a 50% decrease of specific binding. Addition of iodide, thiocyanate, or nitrate to the incubation mixture decreased the affinity of [3H]SR 95531 for its binding site; Na+ had no effect. Subcellular fractionation showed that 74% of the P2 binding was in synaptosomes; 31% of the total homogenate binding was in P2 and 50% in P3. The binding of [3H]SR 95531 was saturable; Scatchard analysis of the saturation isotherm revealed two apparent populations of binding sites (KD of 6.34 nM and Bmax of 0.19 pmol/mg of protein; KD of 32 nM and Bmax of 0.81 pmol/mg of protein). The binding of [3H]SR 95531 was reversible, and association and dissociation kinetics confirmed the existence of two binding sites. Only GABAA ligands were effective displacers of [3H]SR 95531. GABAA antagonists were relatively more potent in displacing [3H]SR 95531 than [3H]GABA; the inverse was true for GABAA agonists. There were marked regional differences in the distribution of binding sites: hippocampus = cerebral cortex > thalamus = olfactory bulb = hypothala‐mus = amygdala = striatum > pons‐medulla and cerebellum. The surprisingly low density of binding sites in the cerebellum was owing to a marked reduction of Bmax values at both the high‐ and the low‐affinity binding sites. In conclusion, the present results demonstrate specific, high‐affinity, saturable, and reversible binding of [3H]SR 95531 to rat brain membranes and strongly suggest that this radioligand labels the GABAA receptor site in its antagonist conformation.
A Novel Chloride‐Dependent L‐[3H]Glutamate Binding Site in Astrocyte Membranes
Authors: Bridges Richard J. , Nieto‐Sampedro Manuel , Kadri Munaf , Cotman Carl W.
Published: October 2006

Abstract: Membrane fractions prepared from astrocytes grown in culture exhibit a specific binding site for L‐[3H]glu‐tamate that is Cl−‐dependent and Na+‐independent. The binding site is a single saturable site with a KD of about 0.5 μM, is inhibited by L‐aspartate, L‐cysteate, and quisqualate, and is insensitive to kainate, N‐methyl‐D‐aspartate, α‐ami‐no‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionate, and 2‐ami‐no‐4‐phosphonobutyrate. The pharmacological characteristics of the binding site indicate that it is distinct from any site previously described in synaptic membrane preparations. Comparisons of ionic requirements, ligand specificity, and inhibitor sensitivities, however, suggest the described binding is the first step in a Cl−‐dependent high‐affinity glutamate uptake system. Such binding studies provide a useful model system in which to investigate the close association between excitatory amino acids, astrocytes, the termination of glutamate's excitatory action by high‐affinity uptake, and the excitotoxic action of acidic amino acids in membranes of a single cell type.
Complex Compartmentation of Tyrosine Sulfate‐Containing Proteins Undergoing Fast Axonal Transport
Authors: Stone George C. , Hammerschlag Richard , Bobinski Judith A.
Published: October 2006

Abstract: The compartmentation of fast‐transported proteins that possess sulfated tyrosine residues—sulfopro‐teins—has been examined for further resolution of the possible significance of sulfated tyrosine in routing and delivery of fast‐transported proteins. In vitro fast axonal transport of [35S]methionine‐ or 35SO4‐labeled proteins was measured in dorsal root ganglion neurons for analysis of protein compartmentation en route and in synaptic regions. When membrane fractions were exposed to Na2CO3 for separation of “lumenal” and peripheral membrane proteins from integral components of the membrane, ∼20% of the [35S]methi‐onine incorporated into fast‐transported proteins was present in a carbonate‐releasable form in the axon, whereas 53% of the incorporated 35SO4 was released by carbonate. Eighty percent of the 35SO4 in this releasable fraction was acid labile, typical of sulfate ester‐linked to tyrosine. Sulfoproteins were also detected in synaptosomes and were released into the extracellular medium in a calcium‐dependent fashion, an observation suggesting that fast‐transported sulfoproteins are secreted. Of the remaining 47% of the fast‐transported 35SO4‐labeled proteins resistant to carbonate treatment (the integral membrane protein fraction), nearly 60% of the 35SO4 was acid labile. Other membrane stripping agents, such as 0.1 M NaOH, 0.5 M NaCl, or mild trypsin treatment, failed to remove acid‐labile 35SO4‐labeled species from carbonate‐treated membrane. Quantitative comparisons of several of the most abundant sulfoproteins resolved via two‐dimensional gel electrophoresis confirmed that ∼7% of each of the species remained associated with carbonate‐treated membranes, presumably as integral membrane components. This complex compartmentation argues against any singular role for tyrosine sulfation as a recognition marker for secretion.