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At least 217 records · Page 12Linked to original sources
PubMed1992

Role of alpha 1A adrenoceptor subtype in production of the positive inotropic effect mediated via myocardial alpha 1 adrenoceptors in the rabbit papillary muscle: influence of selective alpha 1A subtype antagonists WB 4101 and 5-methylurapidil.

In order to elucidate the contribution of alpha 1A subtype to the positive inotropic effect mediated by myocardial alpha 1 adrenoceptors, the influence of the alpha 1A selective antagonists WB 4101 and 5-methylurapidil on the alpha 1-mediated positive inotropic effect (induced by phenylephrine in the presence of a beta adrenoceptor blocking agent bupranolol) was assessed in the isolated rabbit papillary muscle. WB 4101 (10(-9)-10(-7) mol/l) shifted the concentration-response curve of the alpha 1-mediated positive inotropic effect to the right in parallel, but the slope of Schild plot did not meet the competitive antagonism: WB 4101 shifted the curve by log one unit at 10(-9) mol/l, whereas it did not cause further shift at higher concentrations of 10(-8) and 10(-7) mol/l. WB 4101 did not affect the beta adrenoceptor-mediated positive inotropic effect. 5-Methylurapidil (10(-9) to 10(-7) mol/l) shifted the curve of alpha 1-mediated positive inotropic effect to the right and downwards in a concentration-dependent manner; the slope of Schild plot calculated at the level of 20% of the maximum response to phenylephrine was close to unity. 5-Methylurapidil at 3 x 10(-7) mol/l abolished the alpha 1-mediated positive inotropic effect. In addition, 5-methylurapidil inhibited the beta adrenoceptor-mediated positive inotropic effect in the same concentration range as it antagonized the alpha 1-mediated positive inotropic effect, indicating that 5-methylurapidil is not selective for myocardial alpha 1 adrenoceptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗
PubMed2001

Genome structure of Ebola virus subtype Reston: differences among Ebola subtypes. Brief report.

We determined the complete genome sequence of Ebola virus subtype Reston (EBO-R) in the Philippines in 1996. The deduced transcriptional signals were highly conserved among Ebola viruses except for the stop signal of L genes. The intergenic regions were composed of 4 to 7 nucleotides, and of 2 characteristic overlaps and a long intergenic region. The glycoprotein (GP) had several amino acid differences from EBO-R isolated in 1989 and 1992. The variety of GP sequences strongly suggests the independent introduction of EBO-R from unknown natural reservoirs in 1996.

Amino Acid Sequence↗
PubMed2006

Examining subtypes of behavior problems among 3-year-old children, Part I: investigating validity of subtypes and biological risk-factors.

This study examined 3-year-old children who were classified as hyperactive (HYP), oppositional-defiant (OD), hyperactive and oppositional defiant (HYP/OD), and non-problem based on mothers' reports of behavior. Using fathers,' teachers,' and observers' ratings of children's behavior, concurrent validity was excellent for the HYP/OD group, moderate for the HYP group, and poor for the OD group. As predicted, both the HYP/OD and HYP groups reported more prenatal/perinatal birth complications and a greater family history of hyperactivity than did non-problem children. Furthermore, the HYP/OD group showed a greater family history of conduct disorder and oppositional defiant disorder (ODD) symptoms than did non-problem children; however, the HYP group also showed a greater family history of ODD than did non-problem children. Results suggest that as early as age 3, these behavior subtypes appear to be linked to biologically-based risk-factors in ways that are consistent with theories of the development of ADHD.

Attention Deficit Disorder with Hyperactivity↗
PubMed2003

Muscarinic receptor subtypes in the human colon: lack of evidence for atypical subtypes.

Characteristics of muscarinic receptors were investigated in circular muscle from normal human colon. In saturation studies (n=18), binding of [3H]quinuclidinyl benzylate (QNB) was of high affinity (K(d) 87.3 pM) and capacity (B(max) 362+/-27 fmol/mg protein), with no differences between ascending and sigmoid colon. Kinetic studies gave a K(d) of 55 pM. Methoctramine and darifenacin displayed biphasic binding profiles, the high affinity components being compatible with a population of approximately 80+/-5% M(2) and 13+/-2% M(3) muscarinic receptors, respectively. Pirenzepine, mamba toxin 1 and mamba toxin 3 were very weak competitors, indicating negligible expression of muscarinic M(1) and M(4) receptors. Six other subtype-preferring antagonists exhibited K(i) values typical of those reported at cloned human muscarinic M(2) receptors. In the presence of methoctramine, pre-treatment with alkylating agent 4-diphenylacetoxy-N-(2-chloroethyl)-piperidine hydrochloride (4-DAMP mustard) inhibited [3H]quinuclidinyl benzylate binding to 26% of sites. Following alkylation of muscarinic M(3) receptors, darifenacin bound to a single low affinity site, indicating binding to muscarinic M(2) receptors.

Adult↗
PubMed2004

Somatostatin receptor subtype 1 and subtype 2 mRNA expression is regulated by nutritional state in rainbow trout (Oncorhynchus mykiss).

Somatostatin receptors (sst) mediate the numerous physiological actions (e.g., aspects of growth, development, and metabolism) of the somatostatin family of peptides. In this study, we used rainbow trout (Oncorhynchus mykiss) to establish the pattern of sst subtype 1A, 1B, and 2 mRNA expression in selected tissues (optic tectum of brain, endocrine pancreas, and liver) and to evaluate nutritional regulation of sst expression. Quantitative real-time reverse transcription-PCR, sensitive to less than 100 copies, revealed that sst1s and sst2 was differentially expressed, both in terms of distribution among the tissues of study and in terms of relative abundance within a particular tissue. Under normal physiological (fed) conditions, sst1B levels were two times greater than those of sst1A in all tissues examined and levels of sst2 were 2-5 times greater those of sst1B, except in optic tectum, in which sst1B and sst2 mRNA levels appeared equal. Nutritional state modulated the pattern of sst1 and sst2 mRNAs expression. Fasting for 2 or 6 weeks reduced the expression of sst mRNAs in optic tectum; whereas, fasting increased the expression of sst mRNAs in both pancreas and liver. Re-feeding animals for 2 weeks following a 4-week fast restored mRNA levels to near those in tissues from animals which were fed continuously. These findings indicate that the pattern of sst expression in optic tectum, pancreas, and liver is regulated by nutritional state.

Animal Feed↗
PubMed1985

Influence of blood gases, Ca2+-entry blockade and angiotensin converting enzyme inhibition on pressor responses to alpha-adrenoceptor agonists: evidence in vivo for subtypes of response independent of receptor subtype?

The pressor responses in the pithed rat to alpha-adrenoceptor agonists can be modified by alterations in arterial blood gas levels or by drugs which interfere with excitation-contraction coupling processes in the vascular smooth muscle, e.g. Ca2+-entry blockers or angiotensin converting enzyme (ACE) inhibitors. However, the extent of these influences depends on which agonist is used. The pressor response to intravenous injection of alpha-adrenoceptor agonists consists of two phases: an initial rapid but transient response (phase I) is followed by a response of slower onset but longer duration (phase II). We have examined the effects of manipulation of arterial blood gases, a Ca2+-entry blocker, nifedipine, and an ACE inhibitor, teprotide, on the pressor responses to a series of alpha-adrenoceptor agonists. In each case, the effects showed selectivity for one or other of the two phases and the differences in susceptibility between agonists could be explained by the relative sizes of the two phases in their responses. In general, phase II was more susceptible to alkalosis, nifedipine and teprotide, so that drugs in which this component predominated were more susceptible to these factors. In contrast there was no direct correlation with the receptor subtypes activated by the agonists.

Adrenergic alpha-Agonists↗
PubMed1987

Opiate receptors and the endorphin-mediated cardiovascular effects of clonidine in rats: evidence for hypertension-induced mu-subtype to delta-subtype changes.

Effects of opiate receptor antagonists on centrally mediated cardiovascular responses to clonidine and beta-endorphin were studied in urethane-anesthetized spontaneously hypertensive Okamoto-Aoki rats (SHR), normotensive Sprague-Dawley rats, and Sprague-Dawley rats made hypertensive with deoxycorticosterone pivalate/salt. Microinjection of 270 pmol of naloxone into the nucleus tractus solitarii (NTS) significantly inhibited the hypotensive and bradycardic response to 5 nmol of similarly administered clonidine in both SHR and normotensive Sprague-Dawley rats. In SHR, a similar inhibition was observed after the delta-opiate receptor antagonist ICI 174864, but not after the mu-receptor antagonist beta-funaltrexamine (both at 270 pmol, intra-NTS), whereas in normotensive Sprague-Dawley rats, beta-funaltrexamine, but not ICI 174864, was an effective inhibitor. The same pattern of differential inhibition was seen when clonidine was given i.v. and the opiate antagonists were given intracisternally in SHR and Sprague-Dawley rats. Intra-NTS microinjection of 280 fmol of beta-endorphin caused hypotension and bradycardia, and these effects were similarly inhibited by ICI 174864 in SHR and by beta-funaltrexamine in Sprague-Dawley rats. In Sprague-Dawley rats made hypertensive by chronic administration of deoxycorticosterone pivalate and salt, the hypotensive and bradycardic effects of intra-NTS clonidine were inhibited by ICI 174864, but not by beta-funaltrexamine, a pattern similar to that in SHR, but different from that in normotensive Sprague-Dawley rats. These results support the hypothesis that beta-endorphin release and subsequent stimulation of opiate receptors in the NTS are involved in the cardiovascular effects of clonidine in rats. These results further suggest, however, that hypertension regulates the subtype of opiate receptors mediating these effects.

Animals↗
PubMed2003

Agonist-dependent trafficking of alpha2-adrenoceptor subtypes: dependence on receptor subtype and employed agonist.

Many G protein-coupled receptors (GPCRs) are internalized from the plasma membrane after agonist exposure. Previously, marked agonist-induced internalization of human alpha2A- and alpha2B-adrenergic receptors (AR) was observed in transfected neuronal rat pheochromocytoma (PC12) cells; alpha2A- and alpha2B-AR were internalized into partly distinct intracellular vesicles (Olli-Lähdesmäki et al., J. Neurosci. 19, 9281-9288, 1999). In this paper, the extent of alpha2-AR internalization was quantitated in human embryonic kidney (HEK-293) and PC12 cells by combined application of cell surface biotinylation and ELISA methods, which allow measurement of protein trafficking in intact, differentiated and undifferentiated cells. Significant subtype-specific (but not cell type-dependent) trafficking of human alpha2-AR was observed by quantitation and immunocytochemistry. Agonist-induced sequestration of alpha2B-AR was markedly reduced after blocking the formation of clathrin-coated vesicles by hyperosmotic sucrose pretreatment. The sequestration of alpha2A-AR was partly inhibited after sucrose pretreatment but could be further reduced after inhibiting the formation of both clathrin-coated and caveolin vesicles by combined pretreatment with hyperosmotic sucrose and filipin. Differences were also observed in the recycling of alpha2A- and alpha2B-AR. The extent of maximal agonist-induced sequestration in PC12 cells was not directly dependent on relative agonist efficacy.

Adrenergic alpha-2 Receptor Agonists↗
PubMed2002

Morphologic subtyping of papillary renal cell carcinoma: correlation with prognosis and differential expression of MUC1 between the two subtypes.

Papillary renal cell carcinoma is now a well-established entity with distinct histological and cytogenetic features. A subdivision has been proposed in correlation with prognosis. Type 1 is the most frequent subtype and appears to have a better prognosis than Type 2. The subdivision is based on microscopic criteria. To investigate these 2 types of papillary renal cell carcinoma, we have compared the clinical features, ancillary factors (TNM stage, Fuhrman grade), survival and MUC1 expression in 25 Type 1 and 12 Type 2 papillary renal cell carcinomas. Type 2 tumors were significantly associated with a higher Fuhrman grade (Grade III frequent; P <.001). Type 2 tumors were also associated with a poorer prognosis than Type 1 (P <.005). Fuhrman grade was significantly associated with prognosis (P <.005). The type and the prognosis were not correlated with the TNM stage. We have shown a differential expression of MUC1 between Type 1 and Type 2 with a polarized expression in Type 1 and a rare expression in Type 2. In conclusion we confirm that the morphologic sub-typing and Fuhrman grade are valuable factors of outcome of papillary renal cell carcinomas and that MUC1 immunostaining is useful in differentiating Type 1 and Type 2 tumors.

Adult↗
PubMed1975

A method fof production or antisera to hepatitis b antigen subtypes, and the distribution of subtypes d and y among norwegian hepatitis b patients.

A method for production of antisera to hepatitis B antigen (HBsAg) subtypes D and Y is described. The method is based on the coupling of HBsAg to a colloidal silica gel (Aerosil), and the selective adsorption of unwanted antibodies from antisera with this preparation. Some results obtained with Norwegian hepatitis patient sera are included.

Animals↗
PubMed2005

Human immunodeficiency virus type 1 subtype B ancestral envelope protein is functional and elicits neutralizing antibodies in rabbits similar to those elicited by a circulating subtype B envelope.

Human immunodeficiency virus type 1 (HIV-1) is a difficult target for vaccine development, in part because of its ever-expanding genetic diversity and attendant capacity to escape immunologic recognition. Vaccine efficacy might be improved by maximizing immunogen antigenic similarity to viruses likely to be encountered by vaccinees. To this end, we designed a prototype HIV-1 envelope vaccine using a deduced ancestral state for the env gene. The ancestral state reconstruction method was shown to be >95% accurate by computer simulation and 99.8% accurate when estimating the known inoculum used in an experimental infection study in rhesus macaques. Furthermore, the deduced ancestor gene differed from the set of sequences used to derive the ancestor by an average of 12.3%, while these latter sequences were an average of 17.3% different from each other. A full-length ancestral subtype B HIV-1 env gene was constructed and shown to produce a glycoprotein of 160 kDa that bound and fused with cells expressing the HIV-1 coreceptor CCR5. This Env was also functional in a virus pseudotype assay. When either gp160- or gp140-expressing plasmids and recombinant gp120 were used to immunize rabbits in a DNA prime-protein boost regimen, the artificial gene induced immunoglobulin G antibodies capable of weakly neutralizing heterologous primary HIV-1 strains. The results were similar for rabbits immunized in parallel with a natural isolate, HIV-1 SF162. Further design efforts to better present conserved neutralization determinants are warranted.

AIDS Vaccines↗
PubMed2001

Subtype-specific translocation of the delta subtype of protein kinase C and its activation by tyrosine phosphorylation induced by ceramide in HeLa cells.

We investigated the functional roles of ceramide, an intracellular lipid mediator, in cell signaling pathways by monitoring the intracellular movement of protein kinase C (PKC) subtypes fused to green fluorescent protein (GFP) in HeLa living cells. C(2)-ceramide but not C(2)-dihydroceramide induced translocation of delta PKC-GFP to the Golgi complex, while alpha PKC- and zeta PKC-GFP did not respond to ceramide. The Golgi-associated delta PKC-GFP induced by ceramide was further translocated to the plasma membrane by phorbol ester treatment. Ceramide itself accumulated to the Golgi complex where delta PKC was translocated by ceramide. Gamma interferon also induced the delta PKC-specific translocation from the cytoplasm to the Golgi complex via the activation of Janus kinase and Mg(2+)-dependent neutral sphingomyelinase. Photobleaching studies showed that ceramide does not evoke tight binding of delta PKC-GFP to the Golgi complex but induces the continuous association and dissociation of delta PKC with the Golgi complex. Ceramide inhibited the kinase activity of delta PKC-GFP in the presence of phosphatidylserine and diolein in vitro, while the kinase activity of delta PKC-GFP immunoprecipitated from ceramide-treated cells was increased. The immunoprecipitated delta PKC-GFP was tyrosine phosphorylated after ceramide treatment. Tyrosine kinase inhibitor abolished the ceramide-induced activation and tyrosine phosphorylation of delta PKC-GFP. These results suggested that gamma interferon stimulation followed by ceramide generation through Mg(2+)-dependent sphingomyelinase induced delta PKC-specific translocation to the Golgi complex and that translocation results in delta PKC activation through tyrosine phosphorylation of the enzyme.

Adenoviridae↗
PubMed2005

Distinct functional properties of native somatostatin receptor subtype 5 compared with subtype 2 in the regulation of ACTH release by corticotroph tumor cells.

In a series of human corticotroph adenomas, we recently found predominant mRNA expression of somatostatin (SS) receptor subtype 5 (sst5). After 72 h, the multiligand SS analog SOM230, which has a very high sst5 binding affinity, but not Octreotide (OCT), significantly inhibited basal ACTH release. To further explore the role of sst5 in the regulation of ACTH release, we conducted additional studies with mouse AtT-20 cells. SOM230 showed a 7-fold higher ligand binding affinity and a 19-fold higher potency in stimulating guanosine 5'-O-(3-thiotriphosphate) binding in AtT-20 cell membranes compared with OCT. SOM230 potently suppressed CRH-induced ACTH release, which was not affected by 48-h dexamethasone (DEX) pretreatment. However, DEX attenuated the inhibitory effects of OCT on ACTH release, whereas it increased the inhibitory potency of BIM-23268, an sst5-specific analog, on ACTH release. Quantitative PCR analysis showed that DEX lowered sst(2A+2B) mRNA expression significantly after 24 and 48 h, whereas sst5 mRNA levels were not significantly affected by DEX treatment. Moreover, Scatchard analyses showed that DEX suppressed maximum binding capacity (B(max)) by 72% when 125I-Tyr3-labeled OCT was used as radioligand, whereas B(max) declined only by 17% when AtT-20 cells were treated with [125I-Tyr11]SS-14. These data suggest that the sst5 protein, compared with sst2, is more resistant to glucocorticoids. Finally, after SS analog preincubation, compared with OCT both SOM230 and BIM-23268 showed a significantly higher inhibitory effect on CRH-induced ACTH release. In conclusion, our data support the concept that the sst5 receptor might be a target for new therapeutic agents to treat Cushing's disease.

Adrenocorticotropic Hormone↗
PubMed2004

Human immunodeficiency virus type 1 Brazilian subtype B variant showed an increasing avidity of the anti-V3 antibodies over time compared to the subtype B US/European strain in São Paulo, Brazil.

The Brazilian variant of human immunodeficiency virus type 1 (HIV-1) subtype B, (serotype B"-GWGR), has a tryptophan replacing the proline in position 328 the HIV-1 envelope. A longer median time period from infection to acquired immunodeficiency syndrome (AIDS) for serotype B (B"-GWGR) infected subjects compared to the B-GPGR US/European strain was reported. In a cohort study, in São Paulo city, 10 B"-GWGR patients had a statistically significant increased avidity of the anti-V3 antibodies, from 79% +/- 33% to 85% +/- 75%, versus from 48% +/- 59% to 32% +/- 17% for the 10 B-GPGR subjects (p = 0.02). The T CD4+ cells showed a mean increase of + 0.45 cells/month for the B-GPGR subjects and for B"-GWGR the slope was + 1.24 cells/month (p = 0.06), for 62 and 55 months of follow up, respectively. RNA plasma viral load decreased from 3.98 +/- 1.75 to 2.16 +/- 1.54 log10 in the B"-GWGR group while B-GPGR patients showed one log10 reduction in viral load from 4.09 +/- 0.38 to 3.17 +/- 1.47 log10 over time (p = 0.23), with a decreasing slope of 0.0042 +/- log10,/month and 0.0080 +/- log10/month, for B-GPGR and B"-GWGR patients, respectively (p = 0.53). Neither group presented any AIDS defining events during the study, according to Center for Diseases Control criteria. Although the sample size is small, these results may indicate that differences in the pathogenicity of the 2 HIV-1 B serotypes which co-circulate in Brazil may be correlated to the avidity of anti-V3 antibodies.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

[The molecular epidemiology of HIV-1 in Belarus in (1996-2004): a predominance of subtype A variants and circulation of subtype B variants].

To study the molecular epidemiology of HIV-1 in Belarus, the genetic sequences of HIV-1 variants were obtained from 50 infected persons, which represented the main stages, risk groups, and geographic areas of the epidemic. The env and gag sequences were studied for HIV-1 variants from 31 persons, the env sequences were for HIV-1 variants from 18 persons, and the gag sequence was for HIV-1 variant from 1 person. Phylogenetic analysis indicated that the sequences of HIV-1 variants from 46 persons were homogenic and evolutionally closely related to IDU-A strains specific for other epidemics in the former Soviet Union are dominating in the epidemic in Belarus. Circulation of epidemiologically unrelated subtype B viruses was also established.

Female↗
PubMed1990

Two pharmacologically distinct alpha 1-adrenoceptor subtypes in the contraction of rabbit aorta: each subtype couples with a different Ca2+ signalling mechanism and plays a different physiological role.

Using the alpha 1-adrenoceptor subtype-selective antagonists chlorethylclonidine (CEC), WB4101, and 5-methyl-urapidil, we have examined the possible heterogeneity in the alpha 1-adrenoceptor populations in rabbit aorta. The alpha 1-adrenoceptor alkylating agent CEC selectively inhibited the phasic component of the norepinephrine-induced contractile response, with little effect on the tonic component. The alpha 1-adrenoceptor occupancy-response relationship defined by the phenoxybenzamine inactivation method was rectangular hyperbolic for the tonic response, whereas that for the phasic response was linear, indicating the different degree of receptor reserve for the two responses. Radioligand binding studies with the nonselective alpha 1-adrenoceptor antagonist radioligand 125I-BE2254 showed that 73-87% of the binding sites in rabbit aorta are CEC sensitive and they are predominantly low affinity sites both for WB4101 (pKd = 8.1) and for 5-methylurapidil (pKd = 7.1). Moreover, alpha 1-adrenoceptor-mediated phosphatidylinositol (PI) hydrolysis was CEC sensitive, and fractional inactivation of alpha 1 receptors with CEC showed equivalent increments in the reduction of PI hydrolysis and phasic contractile response, suggesting that both responses are linearly related to the CEC-sensitive receptor sites. The Schild plots for the competitive antagonists WB4101 and 5-methyl-urapidil against alpha 1a-adrenoceptor-selective agonist methoxamine-induced contraction were linear and had slopes not significantly different from unity, with a pA2 of 9.07 +/- 0.07 (n = 5) for WB4101 and 9.09 +/- 0.05 (n = 3) for 5-methyl-urapidil. However, the Schilod plots for these antagonists against norepinephrine were curvilinear. Computer-assisted analysis of these curvilinear Schild plots in a two-receptor system indicated that alpha 1-adrenoceptor populations responsible for the constrictive response are predominantly (approximately 80-90%) low affinity sites for the two antagonists (pKd approximately 8.1 for WB4101 and pKd approximately 7.1 for 5-methyl-urapidil) and a small population (approximately 10-20%) are high affinity sites (pKd approximately 9.1 for both WB4101 and 5-methyl-urapidil), which was in good agreement with radioligand binding studies.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1988

Diagnosis and subtyping of depressive disorders by quantitative electroencephalography: IV. Discriminating subtypes of unipolar depression.

Of 216 symptomatic adult depressives who underwent comprehensive inpatient biomedical assessment of their illness, 111 met Research Diagnostic Criteria for primary unipolar depressive disorder. Seventy of these patients were segregated into two groups having different frequency analysis profiles as determined by quantitative electroencephalography (QEEG). The following variables were assessed and tabulated for each of the seventy patients: age and sex; presence of endogenous, nonendogenous or atypical symptoms, cognitive impairment, anxiety, obsessive-ruminative thinking, panic and/or phobic symptoms; abnormalities of the dexamethasone suppression test (DST) and the thyrotropin releasing hormone stimulation test (TRHST). Frequency of occurrence of each variable was compared between groups. Two variables were significant--age and TRHST abnormalities. The patients in group 1, characterized electrophysiologically by beta deficit with or without slow wave excess, were older and had more TRHST abnormalities than the patients in group 2, who were characterized electrophysiologically by having slow wave excess only. The implications of these preliminary findings for objective diagnostic subtyping of depression are discussed.

Adult↗