Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 97
Filter
Add more filters

Country/Region as subject
Publication year range
1.
Eur Spine J ; 25(2): 379-84, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26423748

ABSTRACT

BACKGROUND: The Cobb angle measurement is well established for the measurement of coronal deformity aspect of scoliotic curves. The effect of positional differences in relation to the apex side of the scoliosis is not yet fully quantified. While theoretically plausible that positioning error with rotation toward the apex of the scoliosis would decrease the Cobb angle, the relations are not investigated yet and were object of this study. MATERIALS AND METHODS: Multiple measurements of the Cobb angle were performed, while turning a spine-pelvic cadaveric specimen with a right-sided thoracic scoliosis of 47° (in neutral position) from 45° to -45° in steps of 5° using biplanar radiography. Statistical methods were applied to find the critical position, in which measurement errors potentially become clinically relevant (Cobb angle deviation >5°). RESULTS: Turning the specimen to the right (toward the apex of the scoliosis) produced during the first -15° of rotation, a Cobb angle ranging from 47° to 45°. At -20°, the Cobb angle was 42°, at -25° rotation 37° and at -30° rotation 36°. Above -30° rotation, the measured Cobb angle decreased to 36° (77 % of the original Cobb angle). No relevant differences were found by rotating the specimen to the left (away from the apex) (47° at neutral rotation and 44° at maximal error rotation of +45°). CONCLUSION: The influence of rotational misplacement of the patient at the time of image acquisition on Cobb angle measurements is negligible for a rotational misplacement of ±20° of rotation for a idiopathic right-sided thoracic scoliosis of 47°. Over 20° of rotational misplacement of the patient toward the apex of the scoliosis falsely decreases the Cobb angle.


Subject(s)
Patient Positioning , Scoliosis/diagnostic imaging , Thoracic Vertebrae/diagnostic imaging , Humans , Image Processing, Computer-Assisted , Radiography , Rotation
2.
Prenat Diagn ; 31(6): 555-9, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21425181

ABSTRACT

OBJECTIVE: To document fetal stress hormone and Doppler changes after intrauterine transfusions (IUTs) in either the intrahepatic portion of the umbilical vein (IHV) or the placental cord insertion (PCI). METHOD: Pregnant women scheduled for IUT for fetal anemia (N = 25) were included prospectively. Cortisol, ß-endorphin and noradrenalin concentrations in fetal plasma and middle cerebral artery pulsatility index before and after transfusion were compared. Transfusions were performed through the (IHV), thus puncturing the fetus, or at the PCI. RESULTS: There were no measurable differences between the transfusion sites. CONCLUSION: In anemic fetuses undergoing transfusion, Doppler changes and fetal stress hormone changes were unrelated to the site of needle insertion.


Subject(s)
Anemia/therapy , Blood Transfusion, Intrauterine , Fetal Diseases/therapy , Fetus/metabolism , Hormones/metabolism , Stress, Physiological/physiology , Anemia/congenital , Anesthetics, Intravenous , Blood Transfusion, Intrauterine/adverse effects , Female , Fetal Blood/chemistry , Fetal Blood/metabolism , Fetal Diseases/blood , Fetal Diseases/metabolism , Health Status Indicators , Hormones/analysis , Hormones/blood , Humans , Hydrocortisone/analysis , Hydrocortisone/blood , Hydrocortisone/metabolism , Middle Cerebral Artery/physiology , Norepinephrine/analysis , Norepinephrine/blood , Norepinephrine/metabolism , Piperidines/administration & dosage , Placebos , Pregnancy , Pulsatile Flow/physiology , Remifentanil , beta-Endorphin/analysis , beta-Endorphin/blood , beta-Endorphin/metabolism
3.
Plant Cell Environ ; 32(5): 497-508, 2009 May.
Article in English | MEDLINE | ID: mdl-19183290

ABSTRACT

Production of reactive oxygen species (ROS) is a widely reported response of plants to wounding. However, the nature of enzymes responsible for ROS production and metabolism in the apoplast is still an open question. We identified and characterized the proteins responsible for the wound-induced production and detoxification of ROS in the apoplast of wheat roots (Triticum aestivum L.). Compared to intact roots, excised roots and leachates derived from them produced twice the amount of superoxide (O2(*-)). Wounding also induced extracellular peroxidase (ECPOX) activity mainly caused by the release of soluble peroxidases with molecular masses of 37, 40 and 136 kD. Peptide mass analysis by electrospray ionization-quadrupole time-of-flight-tandem mass spectrometry (ESI-QTOF-MS/MS) following lectin affinity chromatography of leachates showed the presence of peroxidases in unbound (37 kD) and bound (40 kD) fractions. High sensitivity of O2(*-)-producing activity to peroxidase inhibitors and production of O2(*-) by purified peroxidases in vitro provided evidence for the involvement of ECPOXs in O2(*-) production in the apoplast. Our results present new insights into the rapid response of roots to wounding. An important component of this response is mediated by peroxidases that are released from the cell surface into the apoplast where they can display both oxidative and peroxidative activities.


Subject(s)
Peroxidase/metabolism , Plant Roots/metabolism , Superoxides/metabolism , Triticum/metabolism , Hydrogen Peroxide/metabolism , Plant Proteins/metabolism , Stress, Physiological , Tandem Mass Spectrometry
4.
J Cell Biol ; 136(4): 895-906, 1997 Feb 24.
Article in English | MEDLINE | ID: mdl-9049254

ABSTRACT

Chicken acidic leucine-rich EGF-like domain containing brain protein (CALEB) was identified by combining binding assays with immunological screens in the chicken nervous system as a novel member of the EGF family of differentiation factors. cDNA cloning indicates that CALEB is a multidomain protein that consists of an NH2-terminal glycosylation region, a leucine-proline-rich segment, an acidic box, a single EGF-like domain, a transmembrane, and a short cytoplasmic stretch. In the developing nervous system, CALEB is associated with glial and neuronal surfaces. CALEB is composed of a 140/130-kD doublet, an 80-kD band, and a chondroitinsulfate-containing 200-kD component. The latter two components are expressed in the embryonic nervous system and are downregulated in the adult nervous system. CALEB binds to the extracellular matrix glycoproteins tenascin-C and -R. In vitro antibody perturbation experiments reveal a participation of CALEB in neurite formation in a permissive environment.


Subject(s)
Avian Proteins , Cell Adhesion Molecules , Epidermal Growth Factor , Epidermal Growth Factor/metabolism , Epidermal Growth Factor/physiology , Membrane Glycoproteins/metabolism , Membrane Glycoproteins/physiology , Nerve Tissue Proteins/metabolism , Nerve Tissue Proteins/physiology , Neurites/physiology , Amino Acid Sequence , Animals , Antibodies, Blocking/pharmacology , Axons/metabolism , Brain Chemistry , Cell Adhesion Molecules, Neuronal/metabolism , Cell Membrane/metabolism , Chick Embryo , Chickens , Chondroitin Sulfates/chemistry , Epidermal Growth Factor/immunology , Leucine , Membrane Glycoproteins/immunology , Molecular Sequence Data , Nerve Tissue Proteins/immunology , Neurites/immunology , Neuroglia/metabolism , Neurons/metabolism , Receptors, Antigen/metabolism , Retina/metabolism , Substrate Specificity , Tenascin/metabolism
5.
J Cell Biol ; 145(4): 865-76, 1999 May 17.
Article in English | MEDLINE | ID: mdl-10330412

ABSTRACT

The formation of axon tracts in nervous system histogenesis is the result of selective axon fasciculation and specific growth cone guidance in embryonic development. One group of proteins implicated in neurite outgrowth, fasciculation, and guidance is the neural members of the Ig superfamily (IgSF). In an attempt to identify and characterize new proteins of this superfamily in the developing nervous system, we used a PCR-based strategy with degenerated primers that represent conserved sequences around the characteristic cysteine residues of Ig-like domains. Using this approach, we identified a novel neural IgSF member, termed neurotractin. This GPI-linked cell surface glycoprotein is composed of three Ig-like domains and belongs to the IgLON subgroup of neural IgSF members. It is expressed in two isoforms with apparent molecular masses of 50 and 37 kD, termed L-form and S-form, respectively. Monoclonal antibodies were used to analyze its biochemical features and histological distribution. Neurotractin is restricted to subsets of developing commissural and longitudinal axon tracts in the chick central nervous system. Recombinant neurotractin promotes neurite outgrowth of telencephalic neurons and interacts with the IgSF members CEPU-1 (KD = 3 x 10(-8) M) and LAMP. Our data suggest that neurotractin participates in the regulation of neurite outgrowth in the developing brain.


Subject(s)
Avian Proteins , Cell Adhesion Molecules, Neuronal/metabolism , Immunoglobulins/metabolism , Membrane Glycoproteins/metabolism , Membrane Proteins/metabolism , Nerve Tissue Proteins/metabolism , Neurites/metabolism , Amino Acid Sequence , Animals , Axons/metabolism , Base Sequence , Brain/metabolism , CHO Cells , COS Cells , Central Nervous System , Chick Embryo , Chickens , Cricetinae , DNA, Complementary , GPI-Linked Proteins , Immunoglobulin G , Membrane Proteins/genetics , Molecular Sequence Data , Nerve Tissue Proteins/genetics , Neurons , Telencephalon
6.
Int J Obstet Anesth ; 39: 74-81, 2019 08.
Article in English | MEDLINE | ID: mdl-30772120

ABSTRACT

INTRODUCTION: This retrospective, matched case-control cohort study describes the incidence, indications, anesthesia techniques and outcomes of pregnancies complicated by surgery in a single tertiary-referral hospital. METHODS: Retrospective review of the hospital records of 171 patients who had non-obstetric surgery in the current pregnancy, between 2001 and 2016. Pregnancy outcomes of these women were firstly compared with all contemporary non-exposed patients (n=35 411), and secondly with 684 non-exposed control patients, matched for age, time of delivery and parity. RESULTS: The incidence of non-obstetric surgery during pregnancy was 0.48%, mostly performed during the second trimester (44%) and under general anesthesia (81%). Intra-abdominal surgery (44%) was the most commonly performed procedure, predominantly using laparoscopy (79%). Women undergoing surgery delivered earlier and more frequently preterm (25% vs. 17%, P=0.018); and birth weight was significantly lower [median (95% CI) 3.16 (3.06 to 3.26) vs. 3.27 (3.22 to 3.32) kg, P=0.044]. When surgery was performed under general anesthesia, low birth weight was more frequent (22% vs 6%, P=0.046). Overall pregnancy outcomes were neither influenced by trimester nor location (intra- vs extra-abdominal) of surgery. However, preterm birth rate secondary to surgery was higher for interventions during the third trimester, compared with other trimesters (10% vs 0, P <0.001). CONCLUSION: Pregnant women who underwent surgery delivered preterm more frequently and their babies had lower birth weights. Laparoscopic surgery did not increase the incidence of adverse pregnancy outcomes. General anesthesia was associated with low birth weight. Whether these associations suggest causation or reflect the severity of the underlying condition remains speculative.


Subject(s)
Anesthesia, General/methods , Pregnancy Complications/surgery , Referral and Consultation , Birth Weight , Female , Humans , Infant, Newborn , Pregnancy , Pregnancy Outcome , Retrospective Studies , Tertiary Care Centers , Time Factors
7.
J Food Prot ; 69(2): 441-3, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16496591

ABSTRACT

The objective of this study was to determine the prevalence of enterohemorrhagic Escherichia coli (EHEC), E. coli O157, Salmonella, and Listeria monocytogenes in retail food samples from Seattle, Wash. A total of 2,050 samples of ground beef (1,750 samples), mushrooms (100 samples), and sprouts (200 samples) were collected over a 12-month period and analyzed for the presence of these pathogens. PCR assays, followed by culture confirmation were used to determine the presence or absence of each organism. Of the 1,750 ground beef samples analyzed, 61 (3.5%) were positive for EHEC, and 20 (1.1%) of these were positive for E. coli O157. Salmonella was present in 67 (3.8%) of the 1,750 ground beef samples. Of 512 ground beef samples analyzed, 18 (3.5%) were positive for L. monocytogenes. EHEC was found in 12 (6.0%) of the 200 sprout samples, and 3 (1.5%) of these yielded E. coli O157. Of the 200 total sprout samples, 14 (7.0%) were positive for Salmonella and none were positive for L. monocytogenes. Among the 100 mushroom samples, 4 (4.0%) were positive for EHEC but none of these 4 samples were positive for E. coli O157. Salmonella was detected in 5 (5.0%) of the mushroom samples, and L. monocytogenes was found in 1 (1.0%) of the samples.


Subject(s)
Escherichia coli/isolation & purification , Food Contamination/analysis , Listeria monocytogenes/isolation & purification , Meat Products/microbiology , Medicago sativa/microbiology , Salmonella/isolation & purification , Agaricales , Animals , Cattle , Consumer Product Safety , Escherichia coli O157/isolation & purification , Food Microbiology , Humans , Incidence , Polymerase Chain Reaction/methods , Washington
8.
Sci Rep ; 6: 35514, 2016 10 17.
Article in English | MEDLINE | ID: mdl-27748454

ABSTRACT

Quantitative Susceptibility Mapping (QSM) MRI at 7 Tesla and 11-Carbon Pittsburgh-Compound-B PET were used for investigating the relationship between brain iron and Amyloid beta (Aß) plaque-load in a context of increased risk for Alzheimer's disease (AD), as reflected by the Apolipoprotein E ε4 (APOE-e4) allele and mild cognitive impairment (MCI) in elderly subjects. Carriers of APOE-e4 with normal cognition had higher cortical Aß-plaque-load than non-carriers. In MCI an association between APOE-e4 and higher Aß-plaque-load was observable both for cortical and subcortical brain-regions. APOE-e4 and MCI was also associated with higher cortical iron. Moreover, cerebral iron significantly affected functional coupling, and was furthermore associated with increased Aß-plaque-load (R2-adjusted = 0.80, p < 0.001) and APOE-e4 carrier status (p < 0.001) in MCI. This study confirms earlier reports on an association between increased brain iron-burden and risk for neurocognitive dysfunction due to AD, and indicates that disease-progression is conferred by spatial colocalization of brain iron deposits with Aß-plaques.


Subject(s)
Amyloid beta-Peptides/metabolism , Brain/metabolism , Cognitive Dysfunction/metabolism , Iron/metabolism , Aged , Aged, 80 and over , Apolipoprotein E4/genetics , Brain/pathology , Case-Control Studies , Cognitive Dysfunction/diagnostic imaging , Demography , Female , Heterozygote , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Organ Size , Positron-Emission Tomography , Prefrontal Cortex/metabolism , Prefrontal Cortex/pathology
9.
Biochim Biophys Acta ; 1159(1): 1-8, 1992 Sep 04.
Article in English | MEDLINE | ID: mdl-1390906

ABSTRACT

The sponge Axinella polypoides contains four different D-galactose binding lectins and one, termed lectin IV, which is specific for hexuronic acids. Only the D-galactose binding lectins were investigated in this study. The complete amino-acid sequence of lectin I, the main component in the crude extract was determined. Lectin I is a homodimer and each subunit comprises 144 amino acids with a M(r) of 15,847 +/- 10, as calculated from the sequence data and determined by mass spectrometry. Each subunit contains one intrachain disulfide bridge between positions 4 and 46. Of lectin II, only the first 49 amino acids of the NH2-terminal end were analysed. This part has 29 amino acids in common with lectin I, including a cysteine residue at position 4, also suggesting an intrachain loop in a identical position as in lectin I. The molecular mass of its subunit is 16,235 +/- 10 Da. Only the first 15 NH2-terminal amino acids of lectins III and V could be sequenced. Lectin V was identical to lectin II in all positions, whereas lectin III showed only 5 residues identical to lectins I or II. Thus, lectins I, II and III are derived from three different genes, whereas lectin V may either be a proteolytic cleavage product, or result from different splicing events or may be derived also from a separate gene. Neither of the four lectins showed any similarity to known lectin sequences of animal or plant origin.


Subject(s)
Lectins/chemistry , Porifera/chemistry , Amino Acid Sequence , Animals , Molecular Sequence Data , Peptide Fragments/chemistry , Protein Structure, Secondary , Sequence Alignment , Sequence Homology, Amino Acid , Solubility
10.
Biochim Biophys Acta ; 1172(1-2): 131-7, 1993 Feb 20.
Article in English | MEDLINE | ID: mdl-7679926

ABSTRACT

Von Ebner's glands (VEG) are small lingual salivary glands. Their ducts open into trenches of circumvallate and foliate papillae, thus influencing the milieu where the interaction between taste receptor cells and sapid molecules takes place. The major secretions of human VEG is a protein with a molecular mass of 18 kDa. The human VEG protein crossreacts with antibodies raised against the rat VEG protein, indicating sequence similarity between the rat and human VEG proteins. This was subsequently confirmed by N-terminal protein sequencing. A cDNA clone, isolated from a human VEG library, contained an insert of 735 bp including an open reading frame that encodes the human VEG protein of 176 amino acids. Comparison of the human and rat VEG proteins revealed an overall identity of 60%. Immunocytochemistry, in situ hybridization and in vitro translation studies demonstrated the human VEG protein to be highly and exclusively expressed in VEG. The VEG proteins are members of the lipocalin protein superfamily and, together with the rat odorant binding protein II, they constitute a new subfamily. Sequence similarity to proteins such as the retinol binding protein and the odorant binding protein which are lipophilic ligand carriers, suggests a possible function for the human VEG protein in taste perception.


Subject(s)
Carrier Proteins/genetics , Salivary Glands/physiology , Salivary Proteins and Peptides/genetics , Amino Acid Sequence , Animals , Base Sequence , Blotting, Western , Carrier Proteins/isolation & purification , Carrier Proteins/metabolism , Cloning, Molecular , Electrophoresis, Gel, Two-Dimensional , Electrophoresis, Polyacrylamide Gel , Gene Expression , Gene Library , Humans , In Situ Hybridization , Lipocalin 1 , Molecular Sequence Data , Molecular Weight , Poly A/genetics , Poly A/isolation & purification , Protein Biosynthesis , RNA/genetics , RNA/isolation & purification , RNA, Messenger , Rats , Restriction Mapping , Salivary Glands/cytology , Salivary Proteins and Peptides/isolation & purification , Salivary Proteins and Peptides/metabolism , Sequence Homology, Amino Acid , Tongue/cytology , Tongue/physiology
11.
Opt Express ; 13(24): 9782-7, 2005 Nov 28.
Article in English | MEDLINE | ID: mdl-19503186

ABSTRACT

We present an optical scheme to actively suppress statistical noise in Laser Speckle Imaging (LSI). This is achieved by illuminating the object surface through a diffuser. Slow rotation of the diffuser leads to statistically independent surface speckles on time scales that can be selected by the rotation speed. Active suppression of statistical noise is achieved by accumulating data over time. We present experimental data on speckle contrast and noise for a dynamically homogenous and a heterogeneous object made from Teflon. We show experimentally that for our scheme spatial and temporal averaging provide the same statistical weight to reduce the noise in LSI: The standard deviation of the speckle contrast value scales with the effective number N of independent speckle as 1/ radicalN.

12.
J Leukoc Biol ; 51(4): 409-14, 1992 Apr.
Article in English | MEDLINE | ID: mdl-1564403

ABSTRACT

Monocytes are characterized by high activity of alpha-naphthyl acetate esterase (ANAE), distinguishing them from all other blood cells. The physiological function of this monocyte marker enzyme has not yet been elucidated. In this study ANAE's potential proteolytic activity was analyzed because serine esterases/proteases can function as effector molecules in cell-mediated cytotoxicity and because monocytes-macrophages are known to exert cytotoxic effects on tumor cells. This enzyme was purified from the monocytic cell line U-937 by preparative isoelectric focusing and a three-step high-performance liquid chromatography that conserved its catalytic activity. It has a molecular mass of 60 kd, and partial amino acid sequence revealed that the enzyme is not identical to known serine esterases/proteases. The purified enzyme failed to digest a couple of peptides, indicating lack of protease activity. In addition, the esterolytic activity of ANAE was not inhibited by protease inhibitors. The isolation and purification of ANAE enable further studies concerning its function in monocytes-macrophages and its relation to monocytic cytotoxicity.


Subject(s)
Esterases/metabolism , Monocytes/enzymology , Amino Acid Sequence , Esterases/antagonists & inhibitors , Esterases/chemistry , Esterases/isolation & purification , Humans , In Vitro Techniques , Molecular Sequence Data , Tumor Cells, Cultured
13.
Int J Biochem Cell Biol ; 30(2): 225-33, 1998 Feb.
Article in English | MEDLINE | ID: mdl-9608676

ABSTRACT

Although few proteins have been studies as thoroughly as serum albumin, a new biological property of this evolutionary ancient protein was recently discovered: The ability of cobra serum albumin (CSA) to specifically sequester lethal endogenous toxins. A study of the structural basis of this property is reported in this contribution. Two independent approaches were used to alter the structure of the CSA at defined positions: Directed mutagenesis and limited proteolysis. The conserved pattern of the disulfide linkages in the primary structure of the serum albumins showed in the case of the cobra snake (Naja naja kaouthia) an anomaly at C11 and C502, which suggested the existence of a unique spatial structure in this protein. The two cysteine residues were singly replaced with the consensus residue, i.e. C11-->F and C502-->T. The former substitution increased the specific neurotoxin binding capacity of the CSA by the factor 1.7 +/- 0.2, whereas the latter replacement reduced it to (25 +/- 2)%. The limited proteolysis yielded the large tryptic peptides T60, T40, T30 and T18, which after isolation by PAGE followed by HPLC had retained a strong toxin affinity. The location of these peptides in the amino-acid sequence was identified by Edman degradation and suggested the order of their release. On the basis of these data, a model of the unfolding and of the activity changes of the CSA caused by the structural perturbations was composed and the kinetic parameters associated with the process were evaluated. The results support the hypothesis of the existence of a structure of multiple homologous domains with a disulfide linkage between C11 and C502 in the native CSA that joins the chain ends to form a dense conformation.


Subject(s)
Cobra Neurotoxin Proteins/chemistry , Proteins/chemistry , Animals , Chromatography, High Pressure Liquid , Cysteine/chemistry , Disulfides/chemistry , Elapidae , Electrophoresis, Polyacrylamide Gel , Kinetics , Models, Molecular , Mutagenesis, Site-Directed , Peptide Fragments/analysis , Protein Conformation , Proteins/genetics , Proteins/ultrastructure , Trypsin
14.
Int J Biochem Cell Biol ; 27(2): 215-24, 1995 Feb.
Article in English | MEDLINE | ID: mdl-7767789

ABSTRACT

Cyclic AMP affinity chromatography applied to various mammalian tissue extracts yielded two proteins in addition to the regulatory subunits of protein kinase. This paper characterizes these proteins and provides a simple procedure for their preparation. The polypeptides (36 kDa and a 19 kDa/21 kDa doublet) were isolated from the cAMP matrix by sequential elution with cAMP solutions of increasing concentrations. Microsequencing was accomplished following chemical or enzymic degradation of isolated polypeptides. Partial amino acid sequences of the 36 kDa protein and analyses of its enzymic activity indicated identity with glyceraldehyde-3-phosphate dehydrogenase whilst the lower MW protein proved to be identical with mammalian nucleoside diphosphate kinase subunits. In both cases, binding to cAMP appeared to occur at the nucleotide (NAD and ATP, respectively) sites. In conclusion, we present a one step-procedure, applicable to tissue and cell extracts, which allows the simultaneous isolation of both glyceraldehyde-3-phosphate dehydrogenase and nucleoside diphosphate kinase. This procedure may help to elucidate the multiple functions of these two important enzymes.


Subject(s)
Glyceraldehyde-3-Phosphate Dehydrogenases/isolation & purification , Nucleoside-Diphosphate Kinase/isolation & purification , Proto-Oncogene Proteins c-myc/isolation & purification , Transcription Factors/isolation & purification , Amino Acid Sequence , Animals , Chromatography, Affinity , Cyclic AMP , Glyceraldehyde-3-Phosphate Dehydrogenases/chemistry , Glyceraldehyde-3-Phosphate Dehydrogenases/metabolism , HeLa Cells , Humans , Molecular Sequence Data , Molecular Weight , Muscle, Skeletal/enzymology , Nucleoside-Diphosphate Kinase/chemistry , Nucleoside-Diphosphate Kinase/metabolism , Peptide Fragments/chemistry , Peptide Fragments/isolation & purification , Proto-Oncogene Proteins c-myc/chemistry , Rabbits , Rats , Saccharomyces cerevisiae/enzymology , Sequence Homology, Amino Acid , Transcription Factors/chemistry
15.
Endocrinology ; 142(3): 1188-94, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11181534

ABSTRACT

We cloned the mouse TRH receptor type 2 (mTRH-R2) gene, which is 92% identical with rat TRH-R2 and 50% identical with mTRH-R1 at the amino acid level, and identified an intron within the coding sequence that is not present in the TRH-R1 gene structure. Similar to its rat homolog, mTRH-R2 binds TRH with an affinity indistinguishable from mTRH-R1, signals via the phosphoinositide pathway like mTRH-R1, but exhibits a higher basal signaling activity than mTRH-R1. We found that regulator of G protein signaling 4 (RGS4), which differentially inhibits signaling by other receptors that couple to Gq, inhibits TRH-stimulated signaling via mTRH-R1 and mTRH-R2 to similar extents. In contrast, other RGS proteins including RGS7, RGS9, and GAIP had no effect on signaling by mTRH-R1 or mTRH-R2 demonstrating the specificity of RGS4 action. Interestingly, RGS4 markedly inhibited basal signaling by mTRH-R2. Inhibition of basal signaling of mTRH-R2 by RGS4 suggests that modulation of agonist-independent signaling may be an important mechanism of regulation of G protein-coupled receptor activity under normal physiologic circumstances.


Subject(s)
RGS Proteins/pharmacology , Receptors, Thyrotropin-Releasing Hormone/physiology , Signal Transduction/drug effects , Thyrotropin-Releasing Hormone/pharmacology , Amino Acid Sequence/genetics , Animals , Blotting, Northern , Cell Line , Cloning, Molecular , Humans , Mice , Molecular Sequence Data , Protein Isoforms/genetics , Protein Isoforms/physiology , Receptors, Thyrotropin-Releasing Hormone/genetics
16.
Endocrinology ; 141(10): 3717-22, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11014227

ABSTRACT

Juxtamembrane residues in the putative third intracellular (I3) loops of a number of G protein-coupled receptors (GPCRs) have been shown to be important for coupling to G proteins. According to standard hydropathy analysis, the I3 loop of the mouse TRH receptor type 1 (mTRH-R1) is composed of 51 amino acids from position-213 to position-263. We constructed deletion and site-specific I3 loop TRH-R mutants and studied their binding and TRH-stimulated signaling activities. As expected, the effects of these mutations on TRH binding were small (less than 5-fold decreases in affinity). No effect on TRH-stimulated signaling activity was found in a mutant receptor in which the I3 loop was shortened to 16 amino acids by deleting residues from Asp-226 to Ser-260. In contrast, mutants with deletions from Asp-222 to Ser-260 or from Asp-226 to Gln-263 exhibited reduced TRH-stimulated signaling. In the region near transmembrane helix 6, single site-specific substitution of either Arg-261 or Lys-262 by neutral glutamine had little effect on signaling, but mutant TRH-Rs that were substituted by glutamine at both basic residues exhibited reduced TRH-stimulated activity. The reduced signaling activity of this doubly substituted mutant was reversed by over expressing the a subunit of Gq. These data demonstrate that the juxtamembrane regions in the TRH-R I3 loop are important for coupling to Gq.


Subject(s)
Heterotrimeric GTP-Binding Proteins/metabolism , Receptors, Thyrotropin-Releasing Hormone/genetics , Receptors, Thyrotropin-Releasing Hormone/metabolism , Amino Acid Sequence/genetics , Amino Acid Substitution , Animals , COS Cells , Female , GTP-Binding Protein alpha Subunits, Gq-G11 , Ligands , Molecular Conformation , Molecular Sequence Data , Oocytes , Receptors, Thyrotropin-Releasing Hormone/drug effects , Receptors, Thyrotropin-Releasing Hormone/physiology , Signal Transduction/drug effects , Thyrotropin-Releasing Hormone/pharmacology , Xenopus laevis
17.
Cell Prolif ; 29(7): 413-25, 1996 Jul.
Article in English | MEDLINE | ID: mdl-8883465

ABSTRACT

The monoclonal antibody (mab) Ki-67 has been used for about 10 years, mainly in tissue sections, to monitor proliferating cells, but so far only very little is known about the proteins it recognizes. The new mabs Ki-S3 and Ki-S5 detect proliferating cells in frozen and paraffin-embedded tissues. They recognize proteins with the same molecular mass as Ki-67 in Western blot and for the first time also in immunoprecipitation experiments. With these mabs we were able to enrich and purify the Ki-67 proteins. Protein sequencing of four peptides of the digested proteins corresponded to the cDNA-deduced amino acid sequence already published for the Ki-67 proteins. Since we were able to immunoprecipitate the Ki-67 proteins, we performed various immunoprecipitation experiments to obtain more information about the nature of these proteins. After radiolabelling L428 cells with [35S]-methionine we were able to immunoprecipitate the Ki-67 proteins after only 5 min of labelling time. In turnover experiments the Ki-67 proteins could not be detected 3 h after the end of labelling. These data indicate a half-life of the Ki-67 proteins of about 90 min. Labelling experiments with [32P]-orthophosphate revealed that the Ki-67 proteins are phosphorylated. After dephosphorylation was blocked with okadaic acid or cell growth was arrested by means of Colcemid, the phosphorylation of the Ki-67 proteins was greatly increased, indicating that the Ki-67 proteins are phosphorylated via serine and threonine, and that the phosphorylation of the Ki-67 proteins increases in cycling cells. Labelling experiments with [3H]-mannose and [3H]-glucose revealed that the protein is weakly N-glycosylated.


Subject(s)
Antibodies, Monoclonal , Ki-67 Antigen/immunology , Ki-67 Antigen/isolation & purification , Amino Acid Sequence , Animals , Blotting, Western , Female , Glycosylation , Humans , Immunohistochemistry , Ki-67 Antigen/metabolism , Mice , Mice, Inbred BALB C , Molecular Sequence Data , Molecular Weight , Nuclear Proteins/metabolism , Phosphorylation , Precipitin Tests , Tumor Cells, Cultured/chemistry , Tumor Cells, Cultured/immunology
18.
Gene ; 50(1-3): 123-32, 1986.
Article in English | MEDLINE | ID: mdl-3556322

ABSTRACT

16 single-site mutations and a 1-bp deletion in the lac operator have been cloned and examined with regard to repressor binding. A 13-bp, central 'core' operator sequence, bp 5-17 of the natural operator, was also synthesized and cloned. Repressor affinity was assessed in vivo by quantitating the level of beta-galactosidase activity resulting from chromosomal operon derepression and in vitro by measuring the stability of repressor-operator complexes. Our results support the general conclusion that the repressor-operator interaction is asymmetric, particularly across the center of the operator sequence, with little or no specific contact at position 12. Some sequence changes in the right side of the operator markedly reduced repressor affinity, indicating that although binding to this half of the sequence has been suggested to be less important than the left half, it still significantly contributes to the binding affinity.


Subject(s)
Lac Operon , Operator Regions, Genetic , Repressor Proteins/metabolism , Transcription Factors/metabolism , Cloning, Molecular , DNA, Bacterial/metabolism , DNA-Binding Proteins/metabolism , Escherichia coli/genetics , In Vitro Techniques , Methylation , Mutation , Nucleic Acid Conformation , Structure-Activity Relationship
19.
FEBS Lett ; 457(3): 522-4, 1999 Sep 03.
Article in English | MEDLINE | ID: mdl-10471841

ABSTRACT

To identify possible ligands of the orphan somatostatin-like receptor 1 (SLC-1), rat brain extracts were analyzed by using the functional expression system of Xenopus oocytes injected with cRNAs encoding SLC-1 and G protein-gated inwardly rectifying potassium channels (GIRK). A strong inward current was observed with crude rat brain extracts which upon further purification by cation exchange chromatography and high performance liquid chromatography (HPLC) yielded two peptides with a high agonist activity. Mass spectrometry and partial peptide sequencing revealed that one peptide is identical with the neuropeptide melanin concentrating hormone (MCH), the other represents a truncated version of MCH lacking the three N-terminal amino acid residues. Xenopus oocytes expressing the MCH receptor responded to nM concentrations of synthetic MCH not only by the activation of GIRK-mediated currents but also by the induction of Ca(2+) dependent chloride currents mediated by phospholipase C. This indicates that the MCH receptor can couple either to the G(i)- or G(q)-mediated signal transduction pathway, suggesting that MCH may serve for a number of distinct brain functions including food uptake behavior.


Subject(s)
Brain Chemistry , GTP-Binding Proteins/metabolism , Hypothalamic Hormones/metabolism , Melanins/metabolism , Pituitary Hormones/metabolism , Potassium Channels, Inwardly Rectifying , Receptors, Somatostatin/metabolism , Amino Acid Sequence , Animals , Chromatography, High Pressure Liquid , Electrophysiology , G Protein-Coupled Inwardly-Rectifying Potassium Channels , GTP-Binding Proteins/genetics , Hypothalamic Hormones/isolation & purification , Hypothalamic Hormones/pharmacology , Ligands , Mass Spectrometry , Melanins/isolation & purification , Melanins/pharmacology , Molecular Sequence Data , Oocytes/physiology , Pituitary Hormones/isolation & purification , Pituitary Hormones/pharmacology , Potassium Channels/genetics , Potassium Channels/metabolism , Rats , Receptors, Somatostatin/genetics , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Signal Transduction , Tissue Extracts/metabolism , Xenopus
20.
J Histochem Cytochem ; 45(2): 251-63, 1997 Feb.
Article in English | MEDLINE | ID: mdl-9016314

ABSTRACT

We report five novel monoclonal antibodies (Ki-S1, Ki-S4, Ki-S6, Ki-S7, and Ki-S8) reactive with a proliferation-related nuclear antigen. In immunoprecipitation and Western blot experiments using crude nuclear extracts, they recognized a protein of 170 kD that, after proteolytic digestion of the immunoprecipitate and sequencing of the resulting peptides, was identified as the alpha-isoform of human topoisomerase II. This was confirmed by testing the antibodies on a highly purified enzyme preparation. Crossreactivity with topoisomerase II beta was ruled out by testing the antibodies on crude extracts from yeast cells expressing the beta-isoform exclusively. The antibodies bind the antigen with different affinities and at different epitopes, apparently located within the carboxyl third of the enzyme. All five antibodies are suitable for archival material after adequate antigen retrieval, thereby enabling retrospective studies. This report illustrates the tissue and subcellular distribution of the antigen through the cell cycle by immunohistochemistry and confocal fluorescence microscopy. The antibodies will be useful tools in further analysis of morphological and functional aspects of topoisomerase II and may serve diagnostic purposes, as well as providing prognostic information in tumor pathology.


Subject(s)
Antibodies, Monoclonal , Antigens, Neoplasm/chemistry , DNA Topoisomerases, Type II/chemistry , Isoenzymes/chemistry , Antibody Specificity , Binding Sites , Blotting, Western , Cell Division , Cell Line , DNA-Binding Proteins , Humans , Microscopy, Confocal
SELECTION OF CITATIONS
SEARCH DETAIL