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At least 1,261 records · Page 70Linked to original sources
PubMed2003

Androgen regulation of SMR2 gene expression in rat submandibular gland: evidence for a graded but not a binary response.

Expression of SMR2, a member of the gene family encoding salivary glutamine/glutamic acid-rich proteins, is regulated by androgens in rat submandibular gland acinar cells. To further characterize SMR2 regulation, we analyzed SMR2 expression during submandibular gland postnatal development and rat puberty at both a global and a single-cell level. Using in situ detection of mature and primary SMR2 transcripts, we show that SMR2 expression is heterogeneous among acinar cells. However, only one cell population with various amounts of mRNAs can be defined. The number of high-expressing cells increases in males during puberty and in females up to 6 weeks of age, suggesting that some factor in addition to acinar differentiation might be important for SMR2 expression in female rats. Involvement of the beta-adrenergic system in regulating SMR2 expression was tested in rats exposed daily to isoproterenol for 4 days. Under these conditions we found an increase in SMR2 expression in female rats, associated with an increase in SMR2 mRNA levels in most acinar cells. This suggests that a signaling cascade, elicited by beta-adrenergic stimuli, might act in concert with androgens to regulate SMR2 expression.

Androgens↗
PubMed2006

Emerging drugs for chronic urticaria.

Chronic urticaria (CU), with or without angioedema, is a frequent disorder defined as the occurrence of pruritic wheals for > 6 weeks. Studies carried out in the last two decades showed that the origin of the disease is autoimmune in up to 50% of cases. Currently available treatments include antihistamines, corticosteroids and ciclosporin; recently, leukotriene receptor antagonists proved effective in a subset of patients as well. For patients with an unremitting and extremely severe disease unresponsive to standard treatments, plasmapheresis and immunosuppressive drugs have been successfully attempted. Recent findings that the autologous plasma skin test scores positive in nearly all patients and that plasmas from patients with both autoimmune and 'idiopathic' chronic urticaria are frequently characterised by signs of thrombin activation (plasma levels of prothrombin fragment F(1.2) are significantly increased) suggest that clotting cascade might be somehow involved in the pathogenesis of CU. These findings put under a new light some rather sparse studies of the effect of drugs active on the coagulation system (heparin and oral anticoagulants) in patients with CU.

Chronic Disease↗
PubMed2006

[Genes involved in sex determination and differentiation].

Chromosomal sex is established at fertilization by the presence of an X or Y chromosome. The first step of male and female development is gonadal specialization in testes or ovaries; all other processes that follow result from secondary effects produced by testis and ovary hormones. Gonadal determination and differentiation and the development of external genitalia involve time- and tissue-specific expression of genes forming a gene cascade. Those genes, their expression profile and their role in the pathological manifestations related to gonadal and external genitalia development will be discussed in this review.

Animals↗
PubMedDate not supplied

Are acidic lipid domains induced by extrinsic protein binding to membranes?

A widely accepted model for the association of extrinsically bound proteins with acidic lipid-containing membranes has been that approach of the protein to the membrane induces a domain of acidic lipids that serves as the protein binding site. This model has been applied to a variety of membrane proteins including those that participate in the proteolytic complex that converts prothrombin to thrombin during the final stages of the blood coagulation cascade. The 'prothrombinase complex' consists of a serine protease (factor Xa), its protein co-factor (factor Va) and the substrate itself (prothrombin), all bound to phosphatidylserine (PS)-containing membranes derived from stimulated platelets. We have used three approaches to test the domain model as it applies to the proteins of this complex. First, phase diagrams describing the mixing of acidic and neutral lipids have failed to provide evidence for extensive acidic lipid domains (on the order of 50 or more lipid molecules) induced by protein biding. Second, pyrene-containing neutral and acidic phospholipids have been used to test for the occurrence of domains of as few as 20-30 lipids associated with binding of the membrane-binding fragment 1 region of prothrombin. Again, no evidence for domains was obtained. Finally, we have shown that binding of these proteins can be described in terms of a generalized model that presumes an acidic-lipid-independent surface adsorption combined with specific binding of acidic lipids to 'm' sites on a protein. Our results suggest that the concept of a protein-induced domain should not be applied indistriminately to explain binding of extrinsic membrane proteins such as the protein kinase C.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Synthesis of laminarin sulfates with anticoagulant activity.

Laminarin sulfates were synthesized without significant degradation of the genuine laminarin chain using SO3/pyridine complex as a sulfation reagent. 6 derivatives with a degree of sulfation (d.s.) ranging from 0.30 to 2.26 could be obtained. According to methylation analysis the C-6-OH-groups of the glucose molecules were preferentially substituted, followed by the OH-groups at C-2 and C-4. The derivatives Lam S1 (d.s. = 0.30) and Lam S2 (d.s. = 0.64) showed no activity in the blood coagulation tests. With increasing d.s. the anticoagulant activity increased until an optimum d.s. of 1.49. Anticoagulant laminarin sulfates showed significant activity in the activated partial thromboplastin time (APTT) test but were less active in the anti-Factor Xa as well as anti-Factor IIa assay. Therefore, the anticoagulant activity of the synthesized laminarin sulfates is due to the interaction at an early stage of the coagulation cascade and neither to a direct inhibition of Factor Xa and IIa nor to an indirect effect mediated by antithrombin III.

Anticoagulants↗
PubMedDate not supplied

Serine esterase inhibitor reduces contractions with isolated trachea and lung strips from guinea pigs induced by phospholipase A2.

The regulation of the phospholipid metabolism (arachidonic acid (AA) cascade) plays a key role in the pathogenetic mechanisms of the various forms of bronchial asthma. This pathogenetic mechanism offers also important therapeutic implications. Since AA liberation is modulated by phospholipase A2 (PLP-A2) the authors studied the effects of PLP-A2 on guinea pig airways under in vitro conditions and their responses to action of protease inhibitor. Experiments were performed in organ bath with lung strips and tracheal spirals from male guinea pigs. PLP-A2 caused in both models dose-dependent contractions. Para-aminomethyl-benzoic acid reduced PLP-A2-induced contractions in lung strips and trachea in a similar way. This reduction is apparently due to inhibition of AA liberation. These experimental findings underline the relevance of AA cascade to pathogenesis of bronchoconstriction and bronchial hyperreactivity. They support the clinical effectiveness of para-aminomethylbenzoic acid demonstrated earlier. The search for new potential antiasthmatic drugs with the site of action on AA liberation from phospholipids requires in vitro test systems. Guinea pig airway preparations proved to be a suitable in vitro model. The inhibition of PLP-A2 by protease inhibitors seems to be a principal (corticosteroid-like) way for modulation of bronchoconstriction.

4-Aminobenzoic Acid↗
PubMed2004

Role of calcium-calmodulin-dependent protein kinase cascade in thyrotropin (TSH)-releasing hormone induction of TSH and prolactin gene expression.

TRH binds to a membrane receptor that activates several intracellular signaling pathways and increases transcription of the TSH and prolactin (PRL) genes. Although TRH induces TSH and PRL gene expression, the underlying mechanism is not clear. In this report we examined the role of the Ca(2+)/calmodulin-dependent protein (CaM) kinase cascade in mediating TRH-stimulated transcription of TSH and PRL. RT-PCR and Western blot analysis were used to show that CaM kinase kinase (CaM-KK) and CaM IV (CaM-KIV) were present in rat anterior pituitary and its cell line GH(3). Next, the effects of constitutively active CaM-KIV (CaM-KIVc) or its dominant negative mutant (CaM-KIVdn) on TSH and PRL promoter activity were tested in GH(3) cells. The results showed that either CaM-KIVc alone or an upstream kinase, CaM-KK, induced the activity of both TSH and PRL promoters. Exposure of GH(3) cells to 100 microm TRH induced CaM-KIV activity within 5 min and, as expected, also increased both TSH and PRL promoter activity. In contrast, cells carrying the CaM-KIVdn isoform had suppressed TRH induction of both TSH and PRL promoter activity. These results indicate that the CaM-KK-CaM-KIV cascade probably plays an important role in TRH induction of TSH and PRL transcriptional activity in pituitary cells.

Animals↗
PubMed1984

Transmembrane signal defect and absence of cancer extract induced leukocyte adherence inhibition (LAI) for leukocytes from patients with advanced cancer.

Leukocytes from patients with early cancer exhibit leukocyte adherence inhibition (LAI) when incubated with extracts of cancer of the same organ and histogenesis, whereas leukocytes from patients with advanced cancer seldom do. To understand the reason for this refractory state, tumor antigen-induced LAI and transmembrane signalling were measured in the same leukocytes. Transmembrane signalling was measured by changes in membrane potential (delta psi) by the [3H]tetraphenylphosphonium equilibration technique. When leukocytes from patients with early breast cancer were incubated with extracts of breast cancer and malignant melanoma they showed delta psi changes consisting of depolarization and hyperpolarization beginning within 0.5 min after addition of the breast cancer extract and finishing 15 min later. Moreover, they showed no delta psi changes when incubated with extracts of normal breast tissue. Leukocytes from subjects without cancer seldom showed delta psi changes. In criss-cross experiments, leukocytes from patients with melanoma only exhibited delta psi changes when incubated with the melanoma extract. There was a strong correlation between cancer extract-induced delta psi change and LAI. The delta psi change was triggered by leukotriene-like mediators from antibody-dependent monocytes. Authentic leukotrienes triggered delta psi changes in all subpopulation of leukocytes. Leukocytes from patients with advanced breast cancer when incubated with breast cancer extract did not transmit a signal or show LAI. Brief elevation of intracellular cyclic AMP restored both delta psi change and LAI induced by breast cancer extracts, indicating that reactive leukocytes are present but in a refractory state. We conclude that leukocytes from patients with advanced cancer do not react in LAI because tumor antigen does not trigger a transmembrane signal to initiate the cascade of biochemical reactions and physiological changes for LAI.

Breast Neoplasms↗
PubMed2006

Using facsimile cascade to assist case searching during a Q fever outbreak.

In September 2002, facsimiles were sent to 360 primary-care physicians alerting them to a local outbreak of Q fever. The physicians subsequently submitted serology samples on significantly more patients than in a previously comparable period in 2001. Facsimile cascade assists effective communication with primary-care physicians in an outbreak investigation.

Complement Fixation Tests↗
PubMed1999

Identification of kinase-phosphatase signaling modules composed of p70 S6 kinase-protein phosphatase 2A (PP2A) and p21-activated kinase-PP2A.

A growing body of evidence indicates that regulation of protein-serine/threonine phosphatase 2A (PP2A) involves its association with other cellular and viral proteins in multiprotein complexes. PP2A-containing protein complexes may exist that contribute to PP2A's important regulatory role in many cellular processes. To identify such protein complexes, PP2A was partially purified from rat brain soluble extracts following treatment with a reversible cross-linker to stabilize large molecular size forms of PP2A. Compared with native (uncross-linked) PP2A, cross-linked PP2A revealed an enrichment of p70 S6 kinase and two p21-activated kinases (PAK1 and PAK3) in the PP2A complex, indicating these kinases may associate with PP2A. The existence of protein kinase-PP2A complexes in rat brain soluble extracts was further substantiated by the following results: 1) independent immunoprecipitation of the kinases revealed that PP2A co-precipitated with p70 S6 kinase and the two PAK isoforms; 2) glutathione S-transferase fusion proteins of p70 S6 kinase and PAK3 each isolated PP2A; and 3) PAK3 and p70 S6 kinase bound to microcystin-Sepharose (an affinity resin for PP2A-PP1). Cumulatively, these findings provide evidence for association of PP2A with p70 S6 kinase, PAK1, and PAK3 in the context of the cellular environment. Moreover, together with the recent reports describing associations of PP2A with Ca2+/calmodulin-dependent protein kinase IV (Westphal, R. S., Anderson, K. A., Means, A. R., and Wadzinski, B. E. (1998) Science 280, 1258-1261) and casein kinase IIalpha (Heriche, J. K., Lebrin, F., Rabilloud, T., Leroy, D., Chambaz, E. M., and Goldberg, Y. (1997) Science 276, 952-955), the present data provide compelling evidence for the existence of protein kinase-PP2A signaling modules as a new paradigm for the control of various intracellular signaling cascades.

Amino Acid Sequence↗
PubMed1995

Suppressors of a Saccharomyces cerevisiae pkc1 mutation identify alleles of the phosphatase gene PTC1 and of a novel gene encoding a putative basic leucine zipper protein.

The PKC1 gene product, protein kinase C, regulates a mitogen-activated protein kinase (MAPK) cascade, which is implicated in cell wall metabolism. Previously, we identified the pkc1-4 allele in a screen for mutants with increased rates of recombination, indicating that PKC1 may also regulate DNA metabolism. The pkc1-4 allele also conferred a temperature-sensitive (ts) growth defect. Extragenic suppressors were isolated that suppress both the ts and hyperrecombination phenotypes conferred by the pkc1-4 mutation. Eight of these suppressors for into two complementation groups, designated KCS1 and KCS2. KCS1 was cloned and found to encode a novel protein with homology to the basic leucine zipper family of transcription factors. KCS2 is allelic with PTC1, a previously identified type 2C serine/threonine protein phosphatase. Although mutation of either KCS1 or PTC1 causes little apparent phenotype, the kcs1 delta ptc1 delta double mutant fails to grow at 30 degrees. Furthermore, the ptc1 deletion mutation is synthetically lethal in combination with a mutation in MPK1, which encodes a MAPK homologue proposed to act in the PKC1 pathway. Because PTC1 was initially isolated as a component of the Hog1p MAPK pathway, it appears that these two MAPK cascades share a common regulatory feature.

Alleles↗
PubMed2006

Mycobacterium smegmatis whmD and its homologue Mycobacterium tuberculosis whiB2 are functionally equivalent.

Mycobacterium smegmatis whmD is is an essential gene involved in cell division. This paper shows that whmD and its homologue whiB2 in Mycobacterium tuberculosis are functionally equivalent. The genes are syntenous, and share significant homology in both their coding and non-coding DNA sequences. Transcription site mapping showed that the two genes possess near-identical promoter elements, and they displayed comparable promoter strengths in a reporter gene assay. The two proteins show near identity in their C-terminus, and polyclonal antiserum to WhmD specifically cross-reacts with a approximately 15 kDa band in M. tuberculosis lysates. Following overexpression of sense and anti-sense constructs in their cognate mycobacterial hosts, whiB2 and whmD transformants displayed a small-colony phenotype, exhibited filamentation, and showed a reduction in viability. These observations reveal that the two proteins are functionally homologous and that their intracellular concentration is critical for septation in mycobacteria. Colonies of M. tuberculosis overexpressing whiB2 were spherical and glossy, suggesting a change in composition of the cell envelope. Filaments of the conditionally complemented M. smegmatis whmD mutant were non-acid-fast, also indicating changes in characteristics of surface lipids. M. smegmatis transformants carrying a whmD-gfp fusion showed a diffuse pattern of fluorescence, consistent with the putative role of WhmD as a regulator. These observations strongly suggest that M. tuberculosis whiB2 is an essential gene and its protein product in all likelihood regulates the expression of genes involved in the cell division cascade.

Bacterial Proteins↗
PubMed1999

A tobacco syntaxin with a role in hormonal control of guard cell ion channels.

The plant hormone abscisic acid (ABA) regulates potassium and chloride ion channels at the plasma membrane of guard cells, leading to stomatal closure that reduces transpirational water loss from the leaf. The tobacco Nt-SYR1 gene encodes a syntaxin that is associated with the plasma membrane. Syntaxins and related SNARE proteins aid intracellular vesicle trafficking, fusion, and secretion. Disrupting Nt-Syr1 function by cleavage with Clostridium botulinum type C toxin or competition with a soluble fragment of Nt-Syr1 prevents potassium and chloride ion channel response to ABA in guard cells and implicates Nt-Syr1 in an ABA-signaling cascade.

Abscisic Acid↗
PubMed1993

[Experimental study on heparin-free cardiopulmonary bypass using nafamostat mesilate (FUT-175) and heparin-coated circuit].

We investigated whether the combination of a new synthetic protease inhibitor, nafamostat mesilate (FUT-175), and heparin-coated cardiopulmonary bypass (CPB) circuit can achieve heparin-free CPB in rabbits. Nine rabbits underwent 2 hours of CPB with heparin-coated circuits. In 4 rabbits (FUT-Group), FUT was administered before (2 mg/kg in bolus) and during (5 mg/kg/hr continuously) CPB. In 5 rabbits (Heparin-Group), heparin was given before (4 mg/kg) and at 1 hour (2 mg/kg) of CPB. Activated clotting time, activated partial thromboplastin time and fibrin degradation products showed no significant differences between the two groups during CPB. However, prothrombin time was significantly (p < 0.05) shorter in FUT-Group than in Heparin-Group. Platelet counts in FUT-Group was significantly lower than Heparin-Group. Massive clots were observed in all of the venous reservoirs of FUT-Group after CPB, whereas there were no major clots in Heparin-Group. The occlusion rate of hollow fibers of the oxygenators was significantly higher in FUT-Group (55 +/- 25%, mean +/- SD) than in Heparin-Group (14 +/- 12%). We concluded that heparin-free CPB with FUT and heparin-coated circuit is difficult in rabbits because activation of the extrinsic coagulation cascade cannot be sufficiently suppressed by FUT.

Animals↗
PubMed2001

How disturbing is it to be approached for a genetic cascade screening programme for familial hypercholesterolaemia? Psychological impact and screenees' views.

OBJECTIVES: To assess the screenees' views on, and the psychological impact of, a family-based genetic screening programme for familial hypercholesterolaemia (FH) and to evaluate non-participation. METHODS: Self-administered questionnaires were filled out at the time of screening and after communication of the test result. Non-participants were interviewed by phone. RESULTS: Of the people approached for screening, 2% did not participated. These 2% were not interested, had already been clinically diagnosed, or were afraid of insurance consequences. 677 screenees participated, of whom 215 (32%) tested FH positive. Less than 5% of the screenees were critical of the approach and the information provided. 20% of the screenees expressed feelings of social pressure. Effects on mood were minimal to absent, as were general 'quality of life' effects. CONCLUSIONS: Screening for FH is highly acceptable to screenees, although social pressure is prevalent. Only a small percentage of people being approached did not participate.

Age Factors↗
PubMed2002

Effects of protein kinase a activation on the responses of primate spinothalamic tract neurons to mechanical stimuli.

Behavioral and anatomical studies by our group have suggested that the protein kinase A (PKA) signal transduction cascade contributes to long-term changes in nociceptive processing at the spinal cord level. In this study, we have examined the effects of activation of the PKA cascade on the responses of spinothalamic tract (STT) neurons to peripheral mechanical stimuli in anesthetized and paralyzed monkeys. PKA in the spinal cord was activated by intra-spinal infusion of forskolin, an activator of adenylate cyclase, by microdialysis. There was a consistent increase in responses to mechanical pressure and pinch stimuli in all STT cells tested when forskolin was administered. Enhanced responses remained at relatively high levels when forskolin had been washed out for 30 min. However, in most STT cells tested (65%), the responses to brushing stimuli were not obviously changed when forskolin was given. Background activity was slightly increased when forskolin was administered. An inactive isomer of forskolin, D-forskolin, did not produce significant effects on cellular activity. The sensitization of STT cells to noxious mechanical stimuli produced by forskolin could be blocked by pretreatment of the spinal cord with the PKA inhibitor, N-[2-((p-bromocinnamyl)amino)ethyl]-5-isoquinolinesulfonamine (H89). The same dose of H89 did not affect the enhanced responses to mechanical stimuli produced by activation of protein kinase G by intra-spinal infusion of 8-bromo-cGMP, indicating that the effect of forskolin was selective. The present data suggest that activation of PKA can preferentially enhance the responses of STT cells to noxious mechanical stimuli without producing an increase in responses to innocuous brushing stimuli. We speculate that the PKA signal transduction cascade may contribute more to secondary mechanical hyperalgesia than to secondary mechanical allodynia.

Animals↗
PubMed2001

Exclusion of SOX9 as the testis determining factor in Ellobius lutescens: evidence for another testis determining gene besides SRY and SOX9.

In mammals the initiation of testis determination usually depends on the Y-chromosomal gene SRY. A few species, however, escape from this rule with a testis determination that is independent of SRY. The mole vole Ellobius lutescens is one of these species. It is not known how testis determination is initiated in this species but it has been suggested that a gene from the sex determination cascade usually acting downstream of SRY is mutated and has taken over the testis-determining function. At present SOX9 is the only candidate gene for which a testis-determining function in the absence of SRY has been observed. To test the hypothesis that testis differentiation in E. lutescens is initiated by SOX9, segregation analysis of SOX9 alleles was performed in an E. lutescens family. As there is no marker data available in this species we screened both Ellobius SOX9 introns for polymorphisms suitable for segregation studies. A biallelic polymorphism was found in the second intron of the SOX9 gene and analysis of this marker in the Ellobius family revealed an inheritance pattern completely independent of the sex of the animals. Thus, SOX9 can be excluded from being the testis-determining factor in E. lutescens. These results provide evidence for another possibly yet unknown gene besides SRY and SOX9 able to exert testis-determining function.

Alleles↗
PubMed1995

Phospholipase C activates protein kinase C during induction of slow Na current in Xenopus oocytes.

Protein phosphorylation by protein kinase C (PKC) has recently been shown to be a key event in the induction of the slow inward Na current observed during sustained depolarization of the Xenopus oocyte membrane. The present work investigates the possible pathways leading to PKC activation. PKC is activated by a series of phospholipid metabolites, such as diacylglycerol (DAG) and arachidonic acid produced by phospholipases C (PLC) and A2 (PLA2) respectively. To test whether PKC activation was dependent upon the phospholipid metabolites produced either by PLC or by PLA2, enzyme activity was reduced using selective inhibitors. Results indicated that inhibition of PLA2 activity and inhibition of the enzymes involved in the arachidonic acid cascade failed to affect Na current amplitude. On the other hand, PLC inhibition caused a marked decrease of Na current amplitude. In another series of experiments, Na current was fully restored, in spite of PLC inhibition, by directly enhancing PKC activity with a powerful activator phorbol 12-myristate 13-acetate. These data strongly suggest that PLC is involved in PKC activation during Na channel induction.

Animals↗