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C Deal

Publications and source records attributed to C Deal.

At least 37 records · Page 2Linked to original sources
PubMed1998

Functional characterization of human N-methyl-D-aspartate subtype 1A/2D receptors.

The human NMDAR2D subunit was cloned, and the pharmacological properties of receptors resulting from injection of transcripts encoding human NMDAR1A and NMDAR2D subunits in Xenopus oocytes were characterized by profiling NMDA receptor agonists and antagonists. We found that glutamate, NMDA, glycine, and D-serine were significantly more potent on hNMDAR1A/2D than on hNMDAR1A/2A or hNMDAR1A/2B. Also, the potencies of NMDA and glycine were higher for hNMDAR1A/2D than for hNMDAR1A/2C. Ifenprodil was more potent at hNMDAR1A/2B than at hNMDAR1A/2D, whereas 5,7-dichlorokynurenate was more potent at hNMDAR1A/2A than at hNMDAR1A/2D. As measured in transiently transfected human embryonic kidney 293 cells, the maximal inward current in the presence of external Mg2 occurred at -40 mV, and full block was not observed at negative potentials. Kinetic measurements revealed that the higher affinity of hNMDAR1A/2D for both glutamate and glycine relative to hNMDAR1A/2A and hNMDA1A/2B can be explained by slower dissociation of each agonist from hNMDAR1A/2D. The hNMDAR1A/2D combination represents a pharmacologically and functionally distinct receptor subtype and may constitute a potentially important target for therapeutic agents active in the human CNS.

Animals↗
PubMed1998

Apparent congenital athyreosis contrasting with normal plasma thyroglobulin levels and associated with inactivating mutations in the thyrotropin receptor gene: are athyreosis and ectopic thyroid distinct entities?

Loss-of-function mutations in the TSH receptor gene (TSH-R), usually leading to asymptomatic hyperthyrotropinemia, have been reported since 1995 in a total of eight pedigrees, with a pattern of transmission suggesting autosomal recessive inheritance. Although normal TSH secretion and action are not necessary for normal migration of the thyroid analage, they are essential for normal thyroid growth and function. In keeping with this concept, we report a severely hypothyroid boy with a normally located but very hypoplastic and hypofunctional thyroid caused by TSH-R loss-of-function mutations. The propositus' maternal great aunt also had apparent athyreosis. The propositus had undetectable uptake on 99mpertechnetate scintigraphy but normal plasma thyroglobulin at 15 days of age. He was found to be a compound heterozygote for TSH-R mutations, with the maternal allele carrying a splicing mutation (G to C transversion at position +3 of the donor site of intron 6) and the other allele a deletion of two nucleotides (2 bases of codon 655 in exon 10). The great aunt's TSH-R was normal. We also report the sex ratio of hypothyroid newborns referred to our center since 1989 with apparent athyreosis (5 girls, 7 boys) and with ectopic thyroid tissue (41 girls, 15 boys). We conclude that different genetic and nongenetic mechanisms for athyreosis and ectopic thyroid are likely, and that these two distinct entities are themselves heterogeneous. Our results further show that inactivating mutations in TSH-R may account for some cases of apparent congenital athyreosis and should be suspected, especially if plasma thyroglobulin levels are normal.

Amino Acid Sequence↗
PubMed1998

Pharmacological characterization of the human ionotropic glutamate receptor subtype GluR3 stably expressed in mammalian cells.

We have cloned the human ionotropic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor GluR3 flip splice variant (hGluR3i) and developed a stable cell line expressing this receptor in HEK293 cells. Electrophysiological recordings demonstrated that glutamate-evoked currents desensitize rapidly, with a mean desensitization time constant of 5.4 ms. Robust glutamate-evoked increases in intracellular Ca++ ([Ca++]i) were observed in the presence of cyclothiazide, which attenuated receptor desensitization. [Ca++]i measurements were used to perform a detailed pharmacological characterization of hGluR3i with reference agonists and antagonists. The results of these studies showed that kainate and domoate were not fully efficacious agonists relative to glutamate. The binding affinities of agonists and competitive antagonists were determined in a [3H]AMPA competition binding assay. There was a good correlation between the functional data and the binding affinities obtained for competitive antagonists. However, the binding affinities of the agonists did not correlate with their functional EC50 values from [Ca++]i data, possibly because the binding assay predominantly measures the desensitized high-affinity state of the receptor. [3H]AMPA binding also was performed on membranes prepared from rat forebrain, and comparison of the data from HEK293 cells expressing hGluR3i and rat forebrain suggest that nearly all of the reference compounds show similar binding activities between the two membrane preparations, with the exception of fluoro-willardiine, kainate and 6-nitro-7-sulfamoylbenzo(f)quinoxaline-2-3-dione (NBQX). These data suggest that cells stably expressing recombinant hGluR3i represent pharmacologically valid experimental systems to study human AMPA receptors.

Animals↗
PubMed1997

Childhood adrenocortical tumors: case series and reevaluation of prognosis--a 24-year experience.

Adrenocortical neoplasms are rare in childhood and adolescence. The prognostic significance of tumor size, weight, and histological grade are still very much unclear. Eleven patients, (3 boys, 8 girls), with a median presentation age of 7 years (range, 0.8 to 16 years) were identified. Six presented with virilizing symptoms, two with cushingoid symptoms, one with both, and two others had nonspecific symptoms. The interval between onset of symptoms and diagnosis was an average of 18 months (median, 8 months). Hormonal profile correlated well with clinical presentation in nine patients. Two patients with nonspecific symptoms had an aldosterone-producing lesion and an androgen-secreting tumor. Ten patients underwent complete surgical excision, with one intraoperative spillage. Median tumor weight was 94.5 g (range, 4 to 750 g). Three lesions were less than 5 cm in maximal width, six were between 5 and 10 cm, and two were greater than 10 cm. Two tumors had capsular or vascular invasion. Three patients received chemotherapy: one who had inoperable metastatic disease, and two based on clinical and histopathologic findings. Ten patients are doing well, without evidence of recurrent disease with a median follow-up of 3 years (range, 9 months to 15 years), eight patients have been followed up for more than 2 years. The medically treated patient who had metastatic disease died 3 years after diagnosis. A review of the pediatric literature, in some cases, indicates that larger tumors have a worse prognosis, while other investigators claim histological grade is more important. The authors' results do not support these conclusions, but rather suggest that in the pediatric population, when excision is complete, guarded optimism is warranted even with tumors larger than 5 cm. Addendum: Since submission of the manuscript, patient 4 has been operated on twice for local recurrences 13 and 16 months after the initial surgery. She was the only patient in the series to have an intraoperative capsular tear. All other surgical patients remain free of disease.

Adolescent↗
PubMed1997

An autosomal dominant form of familial persistent hyperinsulinemic hypoglycemia of infancy, not linked to the sulfonylurea receptor locus.

Persistent hyperinsulinemic hypoglycemia of infancy (PHHI), a rare disorder due to defective negative feedback regulation of insulin secretion by low glucose levels, is often familial. Most cases are recessively inherited, and mutations of the sulfonylurea receptor gene (SUR) or the closely linked KIR6.2 gene have been found in several families. Both of these genes encode components of the potassium channels responsible for glucose-regulated insulin release. However, in some families recessive PHHI is not linked to the SUR-KIR6.2 locus, suggesting genetic heterogeneity. We report here a French Canadian kindred with hypoglycemia in five first cousins. All five patients had documented hypoglycemia, and all responded well to diazoxide. In two, inappropriately elevated insulin levels during hypoglycemia were documented. This familial clustering strongly suggests the existence of an autosomal dominant form of PHHI. By preliminary linkage analysis, we tested the possibility of a dominant negative SUR or KIR6.2 mutant. The insulin (INS) and glucokinase (GCK) genes were also tested as additional candidates. Microsatellite markers closely linked to each gene were used, and large negative Lod scores were obtained at the known recombination fractions between all three genes studied and the corresponding marker. We conclude that mutation of a gene other than SUR or KIR6.2 is responsible for the dominant PHHI in this family, and this gene cannot be INS or GCK. We propose that a genome-wide search for this gene is important for elucidating this rare disorder and, more importantly, for determining its potential impact on understanding noninsulin-dependent diabetes mellitus and on the effort to develop bioengineered beta-cells for transplantation.

ATP-Binding Cassette Transporters↗
PubMed1997

A novel mechanism for isolated central hypothyroidism: inactivating mutations in the thyrotropin-releasing hormone receptor gene.

Isolated central hypothyroidism, characterized by insufficient TSH secretion resulting in low levels of thyroid hormones, is a rare disorder. We report a boy in whom isolated central hypothyroidism was diagnosed at 9 yr of age. Complete absence of TSH and PRL responses to TRH led us to speculate that he had an inactivating mutation of the TRH receptor gene. The patients' genomic DNA was isolated, and the entire coding region of the TRH receptor was amplified by the PCR and sequenced directly. Confirmation of the mutations and haplotyping of the family was performed using restriction enzymes. The biological activity of the wild-type and mutated TRH receptors was verified by evaluating the binding of labeled TRH and stimulation by TRH of total inositol phosphate accumulation in transfected HEK-293 and COS-1 cells. The patient was found to be a compound heterozygote, having inherited a different mutated allele from each of the parents; both mutations were in the 5'-part of the gene. Mutated receptors were unable to bind TRH and to activate total inositol phosphate accumulation. Our report is the first description of naturally occurring inactivating mutations of a G protein-coupled receptor linked to the phospholipase C second messenger pathway. The prevalence and phenotypic spectrum of TRH receptor mutations in isolated central hypothyroidism remain to be established.

Cell Line↗
PubMed1996

Polymorphic functional imprinting of the human IGF2 gene among individuals, in blood cells, is associated with H19 expression.

In most non-neoplastic tissues studied to date, IGF2 is expressed only from the paternal allele and H19 is expressed only from the maternal allele. The choroid plexus, the only normal tissue to date where IGF2 is expressed from both parental alleles, does not express H19. We present an additional situation in which biallelic IGF2 expression is associated with the absence of H19 transcription in normal tissue: blood cells. In blood cells, functional IGF2 imprinting was found to be a polymorphic trait among individuals: expression was biallelic in 79 out of 85 individuals, but the remaining 6 expressed a single allele. Only the latter expressed H19. Finally, the familial clustering of functional IGF2 imprinting in blood cells suggests that the trait may be genotype-dependent.

Alleles↗
PubMed1996

Pharmacodynamics and enantioselective pharmacokinetics of carprofen in the cat.

The pharmacodynamics and enantioselective pharmacokinetics of the arylpropionic acid non-steroidal anti-inflammatory drug, carprofen, were investigated in cats after administration of the racemic mixture (rac-carprofen) at dose rates ranging from 0.7 to 4.0 mg kg-1 intravenously and subcutaneously. A low dose of rac-carprofen (0.7 mg kg-1) partially inhibited the rise in skin temperature at a site of acute inflammation but had no effect on the ex vivo synthesis of serum thromboxane (Tx) B2. A higher dose (4.0 mg kg-1) inhibited oedematous swelling, although the response was statistically significant at only one time, and also reduced the ex vivo synthesis of serum TxB2 for 12 hours after intravenous injection or 24 hours after subcutaneous injection. The main features of carprofen pharmacokinetics were a low distribution volume, a relatively long elimination half-life, the predominance of the R(-) enantiomer and a bioavailability (after subcutaneous dosing) of 100 per cent and 92 per cent, respectively, after doses of 0.7 and 4.0 mg kg-1. On the basis of these data, it is suggested that a dose of 4.0 mg kg-1 by both intravenous and subcutaneous routes should be evaluated in clinical subjects.

Animals↗
PubMed1996

Effects of 14-day infusions of growth hormone and/or insulin-like growth factor I on the obesity of growing Zucker rats.

The response of fat tissue to GH or insulin-like growth factor I (IGF-I) differs between humans with hypopituitarism and those with exogenous obesity; the effects of combined GH and IGF-I administration have not been compared in these two situations. In GH-deficient dwarf rats (who have a primary GH deficiency), the excessive fat deposition induced by a high fat diet is completely reversed by combined infusion of GH and IGF-I. Whether the same phenomenon would be observed in genetically obese Zucker rats (in whom, as in obese humans, the decrease in GH secretion is secondary to the obese state) remained to be determined. Growing (6-week-old) female obese Zucker rats received a continuous sc infusion of vehicle, recombinant human GH, recombinant human IGF-I, or GH plus IGF-I for 14 days (3 mg/kg x day for both GH and IGF-I). Combined GH and IGF-I stimulated body weight gain and in naso-anal length to the same extent as IGF-I alone, whereas GH alone was less potent. Because all treatments stimulated weight linear growth proportionately, the progression of obesity was similar in treated and control animals. However, GH plus IGF-I (but not either agent alone) induced a 25% decrease in the relative weight of inguinal fat. GH and IGF-I exerted distinct effects on the relative weights of liver, kidney, and spleen and on the circulating levels of IGF-I and IGF-binding protein-3. Circulating glucose and insulin levels did not change in any group. In summary, GH plus IGF-I infusions decrease the relative weight of inguinal fat in Zucker rats as in obese GH-deficient dwarf rats; however, this effect is of more modest magnitude despite the use of a 2- to 3-fold higher dose and is limited to the inguinal site. Thus, GH plus IGF-I infusions did not influence the obesity index in Zucker rats. Inasmuch as Zucker rats are a better model of childhood-onset obesity than dwarf rats fed a high fat diet, the present results do not appear promising for extrapolation to clinical studies in children. The mechanisms by which the primary vs. secondary nature of the decreased GH secretion influences the effect of GH plus IGF-I on obesity remain to be determined.

Analysis of Variance↗
PubMed1996

Cloning and functional characterization of human heteromeric N-methyl-D-aspartate receptors.

Human cDNAs encoding N-methyl-D-aspartate receptor type (NMDAR)1A, NMDAR2A and NMDAR2B subunits were cloned and receptors encoded by these cDNAs were functionally expressed by injection of the respective mRNAs in Xenopus oocytes. The pharmacological properties of recombinant human N-methyl-D-aspartate (NMDA) receptors were characterized by profiling two agonists and four antagonists at both the NMDA and glycine sites in voltage-clamped oocytes. NMDA, glycine and D-serine were significantly more potent at human NMDAR (hNMDAR)1A/2B receptors than at nNMDAR1A/2A, whereas there was no detectable subtype-dependent difference in the potency of glutamate. Of the NMDA-site antagonists tested, CGP 43487 and 3-(2-carboxypiperazin-4-yl) propyl-1-phosphonate exhibited 5.8- and 3.9-fold greater potency, respectively, at hNMDAR1A/2A receptors than at hNMDAR1A/2B. Of the four glycine-site competitive antagonists tested, L-689,560 displayed 5-fold greater potency at hNMDAR1A/2A, whereas 5,7-dichlorokynurenic acid, HA-966 and CGP 58411 did not discriminate between hNMDAR1A/2A and hNMDAR1A/2B. Receptors resulting from injection of hNMDAR1A, hNMDAR2A and hNMDAR2B transcripts in a 1:1:1 ratio were indistinguishable from hNMDAR1A/2B receptors in terms of their sensitivity to NMDA, glycine, D-serine, CGS 19755 and CGP 40116. Ifenprodil was approximately 350-fold more potent at hNMDAR1A/2B than at hNMDAR1A/2A receptors. Ifenprodil sensitivities of receptors formed in oocytes injected with a constant amount of hNMDAR1A mRNA but varying ratios of hNMDAR2A or hNMDAR2B mRNAs were compared. The receptors expressed at a 10:1 ratio of 2A:2B transcripts displayed an ifenprodil sensitivity that would be predicted for a population in which 51% was represented by hNMDAR(1A)2(2A)3 complexes. Our results underscore the need for subtype-selective compounds acting at novel sites to sufficiently probe the pharmacological differences between NMDA receptor subtypes formed by different subunit combinations.

Animals↗
PubMed1996

Stable expression and characterization of recombinant human heteromeric N-methyl-D-aspartate receptor subtypes NMDAR1A/2A and NMDAR1A/2B in mammalian cells.

The electrophysiological and pharmacological properties of two mammalian cell lines stably transfected with cDNAs encoding recombinant human N-methyl-D-aspartate (NMDA) receptor subtypes NMDAR1A/2A and NMDAR1A/2B are described. In whole-cell electrophysiological recordings, application of NMDA/glycine elicited inward currents at negative holding potentials in human NMDAR1A/2A (hNMDAR1A/2A)- and hNMDAR1A/2B-expressing cells. The current-voltage relationships determined in both cell lines in the presence and absence of external Mg++ were similar to those observed with recombinant rat NMDA receptors. Power spectra calculated from NMDA/glycine-induced currents for both NMDA receptor-expressing cell lines suggested a kinetically homogeneous population of channels. Immunoprecipitation with an anti-NMDAR1A antibody coprecipitated the corresponding NMDAR2 subunit with the NMDAR1A, suggesting that heteromeric complexes are formed in these stable cell lines. Stimulation of NMDA receptors evoked an increase in intracellular Ca++, which was used to characterize their pharmacological properties. NMDA displayed less intrinsic activity than did glutamate in both NMDA receptor-expressing cell lines and was a 4-fold more potent agonist at hNMDAR1A/2B than hNMDAR1A/2A. NMDA/glycine-evoked increases in Ca++ levels were inhibited by CGS 19755, (+/-)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonate, MK-801, ketamine and ifenprodil. (+/-)-3-(2-Carboxypiperazin-4-yl)propyl-1-phosphonate was a 3-fold more potent antagonist at hNMDAR1A/2A than hNMDAR1A/2B, whereas ifenprodil was markedly more selective toward hNMDAR1A/2B, being 250-fold more potent than against hNMDAR1A/2A. These data suggest that cells stably expressing recombinant heteromeric hNMDAR1A/2A and hNMDAR1A/2B represent pharmacologically valid experimental systems to study human NMDA receptors.

Animals↗
PubMed1995

The use of ultra-low-dose aprotinin to reduce blood loss in cardiac surgery.

One hundred patients due to undergo primary cardiac surgery were prospectively randomized to receive aprotinin or placebo. In the aprotinin group, 250,000 kallikrein inhibitory units (KIU) of aprotinin were added to the cardiopulmonary bypass prime solution. A further 250,000 KIU of aprotinin were infused intravenously over 30 minutes immediately before the start of cardiopulmonary bypass. The control group received 0.9% saline in equal volumes at identical times. The study was designed to have a 90% chance of demonstrating a 30% reduction in blood loss. No significant differences were found between the two groups. The median blood loss in the aprotinin group was 750 mL (interquartile range 556 to 1025 mL, 95% confidence interval 600 to 800 mL). In the control group, the median blood loss was also 750 mL (interquartile range 500 to 988 mL, 95% confidence interval 625 to 925 mL). In the aprotinin group, 12 patients received postoperative autotransfusion of shed mediastinal blood of median volume of 665 mL (interquartile range 500 to 925 mL, 95% confidence interval 450 to 1000 mL). In the control group, 14 patients received postoperative autotransfusion of mediastinal blood of median volume of 663 mL (interquartile range 600 to 800 mL, 95% confidence interval 600 to 700 mL). Five patients in the aprotinin group and seven patients in the control group required postoperative homologous blood transfusion. Reassessment of inclusion criteria showed a 19% reduction in blood loss in patients undergoing only aortocoronary bypass receiving aprotinin compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Aprotinin↗
PubMed1994

Admissions to a pediatric intensive care unit for status epilepticus: a 10-year experience.

OBJECTIVE: To characterize the etiology, course, and prognosis in children admitted to a pediatric intensive care unit (ICU) for status epilepticus. DESIGN: Retrospective, descriptive study. SETTING: Pediatric ICU in a university hospital. PATIENTS: One hundred forty-seven children admitted with status epilepticus. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Status epilepticus was defined as a prolonged (> 30 mins) or repeated tonic or tonic-clonic seizure with a persistent altered state of consciousness. Over 10 yrs, 147 children 0 to 16 yrs of age (median 1; mean 3.4 +/- 3.9 [SD]) were admitted to a pediatric ICU for, or with, 153 episodes of status epilepticus. Status epilepticus was caused most often by epilepsy (n = 52), atypical febrile convulsions (n = 21), bacterial meningitis (n = 20), encephalitis (n = 20), intoxication (n = 8), or a metabolic disorder (n = 12). Two infants, 1 and 3 months of age, and a patient with intoxication by isoniazid, responded to pyridoxine. Among 114 previously normal children, 34 patients displayed a new neurologic problem on discharge from the ICU, among whom, 68% (23/34) still had some neurologic abnormality 1 yr after the episode of status epilepticus. Nine patients died during their ICU stay, mostly from underlying disease rather than from the status epilepticus itself. A normal neurologic status before status epilepticus and age < 4 yrs seem to be markers of good prognosis, while encephalitis and meningitis appear to be markers for morbidity and mortality. CONCLUSIONS: Most cases of status epilepticus were caused by epilepsy, atypical febrile seizure, encephalitis, meningitis, or metabolic disease. The mortality rate during the ICU stay was 6%. The prognosis was good in most surviving cases, more so if the neurologic development of the child was normal before the status epilepticus.

Adolescent↗
PubMed1993

Functional polymorphism in the parental imprinting of the human IGF2R gene.

The murine genes coding for insulin-like growth factor II (Igf2) and its specific receptor (Igf2r) are parentally imprinted, with exclusive expression from the paternal (Igf2) or maternal (Igf2r) gene copy. We have demonstrated that the human IGF2 gene is imprinted, like its murine homologue. To examine whether the human IGF2R is also imprinted, we used CA repeat polymorphisms of the cDNA sequence to distinguish expression from each copy. Unlike the mouse, most subjects equally expressed both gene copies. However, two out of 14 informative fetuses showed exclusive expression from the maternal gene copy. We conclude that the human IGF2R gene is parentally imprinted, like its murine homologue, but only in a minority of individuals. This is the first direct demonstration of imprinting as a polymorphic trait, a property that had been observed in transgene methylation and predicted from the behavior of certain human tumors.

Animals↗
PubMed1993

Parental genomic imprinting of the human IGF2 gene.

The mouse igf2 gene, coding for the insulin-like growth factor II (IGF-II) is parentally imprinted, only the gene copy derived from the father is expressed. To know whether IGF2, the human homologue, is also imprinted, we used an ApaI polymorphism at the 3' untranslated region in order to distinguish between mRNA derived from each copy of the gene in placentae from heterozygote human fetuses, studied after careful removal of the decidua. Six term and two pre-term placentae of heterozygotes were studied, and in each case the cDNA contained only one of the two alleles present in the genomic DNA. In three cases the mother was homozygous for the non-expressed allele, allowing assignment of paternal origin to the transcribed gene copy. We conclude that, as in the mouse, human IGF2 is parentally imprinted.

Alleles↗