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1.
Acta Diabetol ; 53(1): 27-33, 2016 Feb.
Article in English | MEDLINE | ID: mdl-25794880

ABSTRACT

BACKGROUND: Emerging adulthood is a challenging period for diabetes management. Our aim was to determine whether a dedicated transition clinic for emerging adults with type 1 diabetes can improve glycemic control and visit attendance. METHODS: An observational study of 53 emerging adults (30 males) treated during 2010-2014 in a newly established transition clinic. The clinic was operated jointly by pediatric and adult endocrinologists and included a transition coordinator. Data collected included the source of referral, HbA1c levels, frequency of visit attendance, and acute complications. For 27 patients who had attended the pediatric clinic at the same medical center, data from up to 2 years preceding the transition were also collected. Patients filled the Diabetes Quality of Life-Youth questionnaire at the transition and 1 year later. RESULTS: Mean ± SD age at the transfer to the transition clinic was 22.1 ± 2.7 years; mean disease duration was 8.4 ± 5.0 years. Follow-up duration at the transition clinic was 1.2 ± 1.1 years. Mean HbA1c levels decreased from 67 mmol/mol (95 % CI 63-72) [8.3 % (95 % CI 7.9-8.7)] at transfer to 57 mmol/mol (95 % CI 52-63) [7.4 % (95 % CI 6.9-7.9)] after 1 year (p < 0.001). Thirty-six patients (68 %) attended three or more visits during their first year in the transition clinic. The impact of diabetes on quality of life, disease-related worries, and life satisfaction did not change significantly during 1-year attendance in the transition clinic. CONCLUSIONS: A dedicated transition clinic for emerging adults, with tailored support according to the developmental needs of emerging adulthood, showed improved glycemic control and visit attendance.


Subject(s)
Blood Glucose/metabolism , Diabetes Mellitus, Type 1/blood , Diabetes Mellitus, Type 1/epidemiology , Patient Participation/statistics & numerical data , Transitional Care/statistics & numerical data , Adolescent , Adult , Ambulatory Care/statistics & numerical data , Blood Glucose/analysis , Child , Child, Preschool , Diabetes Mellitus, Type 1/therapy , Female , Humans , Male , Quality of Life , Referral and Consultation , Surveys and Questionnaires , Transition to Adult Care/statistics & numerical data , Young Adult
3.
Epidemiol Infect ; 139(9): 1379-87, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21087537

ABSTRACT

We determined the extent by which mandatory reporting on isolates of Shigella and Salmonella underestimates the burden of diarrhoeal diseases in individuals aged <17 years in Israel and examined paediatricians' knowledge, attitudes and practices related to patient visits with diarrhoeal diseases. Sources of data were a nationwide population-based telephone survey for presence of diarrhoeal diseases, Maccabi Healthcare Services databases and a mail survey among its paediatricians. Monte Carlo simulation and rate estimates for all stages, from visit to physician to reporting on a culture-confirmed case of shigellosis or salmonellosis, were used to determine the underestimation factor. Of 1492 children, 5·7% reported a diarrhoeal episode during the 2 weeks prior to interview. The rate of visiting a physician with and without fever was 86% and 16%, respectively. A stool culture was performed for around 20% of patients and the isolation rates were 7·1% for Shigella and 2·1% for Salmonella. Paediatricians (n=214) ranked very young age of patient and the complaint 'bloody diarrhoea' as the most important determinants. We estimated that one reported isolate of Shigella or Salmonella represented 152 diarrhoeal episodes of all aetiologies. This estimate is important for further assessments of the true burden of diarrhoeal diseases.


Subject(s)
Cost of Illness , Diarrhea/epidemiology , Diarrhea/microbiology , Health Knowledge, Attitudes, Practice , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Israel/epidemiology , Male
4.
Eur J Clin Microbiol Infect Dis ; 27(11): 1045-51, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18528721

ABSTRACT

Increased resistance among isolates causing bacteremia constitutes a major challenge to medical practitioners and institutions. Variability between institutes is substantial, and requires the individual analysis of local trends. An eight-year (1997-2004) surveillance study of episodes of bacteremia was conducted in an 850-bed university hospital in central Israel. Trends of incidence, resistance, age, and mortality were analyzed. We studied 6,096 patient-unique episodes of bacteremia, of which, 2,722 (45.3%) were nosocomial and 523 (9.2%) involved children less than 18 years of age. The overall incidence of bacteremia episodes has increased over the study years by 39% and the patient mean age by 7.5 years. Gram-negative organisms accounted for 72% of hospital-acquired cases and 69% of community-acquired cases. There was a substantial increase in the incidence of nosocomial episodes, predominantly due to Gram-negative isolates, mainly Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli. Increased resistance to broad-spectrum antibiotics was noted among Gram-negative organisms, including quinolones (in K. pneumoniae), imipenem (A. baumannii and P. aeruginosa), piperacillin-tazobactam (K. pneumoniae), and amikacin (A. baumannii and P. aeruginosa). Increased resistance to oxacillin among coagulase-negative staphylococci was also noted. The all-cause mortality rates showed a significant rise. The patient age, intensive care unit (ICU) stay, and hospital acquisition were independently associated with mortality. We describe an increase in the incidence and resistance of Gram-negative organisms causing bacteremia and concomitant ageing of the patients with bacteremia. Similar patterns have been reported from other localities, and are of real concern.


Subject(s)
Bacteremia/epidemiology , Bacteremia/microbiology , Academic Medical Centers , Adolescent , Aged , Aged, 80 and over , Anti-Bacterial Agents/pharmacology , Bacteremia/mortality , Child , Child, Preschool , Community-Acquired Infections/epidemiology , Community-Acquired Infections/microbiology , Community-Acquired Infections/mortality , Cross Infection/epidemiology , Cross Infection/microbiology , Cross Infection/mortality , Drug Resistance, Bacterial , Female , Gram-Negative Bacterial Infections/epidemiology , Gram-Negative Bacterial Infections/microbiology , Gram-Negative Bacterial Infections/mortality , Gram-Positive Bacterial Infections/epidemiology , Gram-Positive Bacterial Infections/microbiology , Gram-Positive Bacterial Infections/mortality , Humans , Incidence , Israel/epidemiology , Male
5.
J Exp Zool ; 290(3): 218-26, 2001 Aug 01.
Article in English | MEDLINE | ID: mdl-11479901

ABSTRACT

The yolk protein of Cherax quadricarinatus contains six major high-density lipoprotein (HDL) subunits with the approximate molecular masses of 177, 155, 106, 95, 86, and 75 kDa, of which only the 106-kDa polypeptide is negatively charged. On the basis of their molecular weights, time of appearance and disappearance, their floating density and susceptibility to enzyme degradation (by a serine proteinase), these six HDL polypeptides were classified into two subgroups. One group comprises the higher-molecular-weight compounds above 106 kDa, and the other includes the lower-molecular-weight compounds up to 95 kDa. Other than being different from the lower-molecular-weight polypeptides, the negatively charged 106-kDa polypeptide was significantly different from members of its higher-molecular-weight group belonging to a different, less abundant, yolk protein as shown by HPLC separation. Immunological studies and peptide mapping in which the 106-kDa polypeptide did not show similarity to any of the other HDL components confirmed these differences. Moreover, the amino acid composition of the 106-kDa polypeptide was different from that of known vitellin from other crustacean species. This unique negatively charged polypeptide presents an enigma as it is known to be a secondary vitellogenic-related HDL polypeptide, immunolocalized in yolk globules; however, it is different to all the other HDL polypeptides, thus presenting the question whether it is indeed a component of "classical" crustacean vitellin.


Subject(s)
Astacoidea/chemistry , Crustacea/chemistry , Egg Proteins/chemistry , Lipoproteins, HDL/chemistry , Animals , Chromatography, High Pressure Liquid , Female , Peptide Mapping , Peptides/chemistry
6.
EMBO J ; 20(5): 1099-113, 2001 Mar 01.
Article in English | MEDLINE | ID: mdl-11230133

ABSTRACT

DRP-1 is a pro-apoptotic Ca2+/calmodulin (CaM)-regulated serine/threonine kinase, recently isolated as a novel member of the DAP-kinase family of proteins. It contains a short extra-catalytic tail required for homodimerization. Here we identify a novel regulatory mechanism that controls its pro-apoptotic functions. It comprises a single autophosphorylation event mapped to Ser308 within the CaM regulatory domain. A negative charge at this site reduces both the binding to CaM and the formation of DRP-1 homodimers. Conversely, the dephosphorylation of Ser308, which takes place in response to activated Fas or tumour necrosis factor-alpha death receptors, increases the formation of DRP-1 dimers, facilitates the binding to CaM and activates the pro-apoptotic effects of the protein. Thus, the process of enzyme activation is controlled by two unlocking steps that must work in concert, i.e. dephosphorylation, which probably weakens the electrostatic interactions between the CaM regulatory domain and the catalytic cleft, and homodimerization. This mechanism of negative autophosphorylation provides a safety barrier that restrains the killing effects of DRP-1, and a target for efficient activation of the kinase by various apoptotic stimuli.


Subject(s)
Apoptosis , Calmodulin/metabolism , Protein Serine-Threonine Kinases/metabolism , Amino Acid Sequence , Amino Acid Substitution , Apoptosis Regulatory Proteins , Calcium/metabolism , Calcium-Calmodulin-Dependent Protein Kinases , Chromatography, Gel , Death-Associated Protein Kinases , Dimerization , Enzyme Activation , Humans , Mass Spectrometry , Models, Molecular , Molecular Sequence Data , Mutation , Myosin Light Chains/metabolism , Phosphorylation/drug effects , Phosphoserine/metabolism , Protein Binding , Protein Serine-Threonine Kinases/chemistry , Protein Serine-Threonine Kinases/genetics , Protein Structure, Tertiary , Sequence Alignment , Static Electricity , Tumor Cells, Cultured , Tumor Necrosis Factor-alpha/pharmacology , fas Receptor/pharmacology
7.
J Bacteriol ; 182(11): 3111-6, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10809689

ABSTRACT

FtsH (HflB) is a conserved, highly specific, ATP-dependent protease for which a number of substrates are known. The enzyme participates in the phage lambda lysis-lysogeny decision by degrading the lambda CII transcriptional activator and by its response to inhibition by the lambda CIII gene product. In order to gain further insight into the mechanism of the enzymatic activity of FtsH (HflB), we identified the peptides generated following proteolysis of the phage lambda CII protein. It was found that FtsH (HflB) acts as an endopeptidase degrading CII into small peptides with limited amino acid specificity at the cleavage site. beta-Casein, an unstructured substrate, is also degraded by FtsH (HflB), suggesting that protein structure may play a minor role in determining the products of proteolysis. The majority of the peptides produced were 13 to 20 residues long.


Subject(s)
Bacterial Proteins/metabolism , Bacteriophage lambda , Endopeptidases/metabolism , Escherichia coli/enzymology , Membrane Proteins/metabolism , Metalloendopeptidases/metabolism , Transcription Factors/metabolism , ATP-Dependent Proteases , Amino Acid Sequence , Caseins/metabolism , Escherichia coli Proteins , Molecular Sequence Data , Substrate Specificity , Transcription Factors/isolation & purification , Viral Proteins
8.
Eur J Paediatr Neurol ; 3(6): 281-4, 1999.
Article in English | MEDLINE | ID: mdl-10595674

ABSTRACT

We describe the clinical, neuroradiological and surgical aspects of two children in whom symptoms attributable to cauda equina compression were caused by spinal arachnoid cysts. The first patient presented with recurrent urinary tract infections due to neurogenic bladder dysfunction, absent deep tendon reflexes and sensory deficit in the lower limbs. The second child presented with unstable gait as a result of weakness and diminished sensation in the lower extremities. Spinal magnetic resonance imaging revealed a lumbosacral arachnoid cyst in both patients. During surgery the cysts were identified and excised. Two years after surgery, the sensory deficits of the first patient have disappeared and patellar and ankle reflexes can be elicited, but there is no improvement in bladder function. Neurological examination of the second patient was normal. We conclude that the diagnosis of cauda equina syndrome should prompt a vigorous search for its aetiology. Lumbosacral arachnoid cysts are a rare cause of cauda equina syndrome in children.


Subject(s)
Arachnoid Cysts/complications , Polyradiculopathy/etiology , Arachnoid Cysts/diagnosis , Arachnoid Cysts/surgery , Child , Child, Preschool , Female , Gait , Humans , Lumbosacral Region , Magnetic Resonance Imaging , Muscle Weakness/etiology , Sensation Disorders/etiology , Urinary Bladder, Neurogenic/etiology , Urinary Tract Infections/etiology
9.
J Biol Chem ; 274(31): 21963-72, 1999 Jul 30.
Article in English | MEDLINE | ID: mdl-10419519

ABSTRACT

Peptides displayed on the cell surface by major histocompatibility class I molecules (MHC class I) are generated by proteolytic processing of protein-antigens in the cytoplasm. Initially, antigens are degraded by the 26 S proteasome, most probably following ubiquitination. However, it is unclear whether this proteolysis results in the generation of MHC class I ligands or if further processing is required. To investigate the role of the 26 S proteasome in antigen presentation, we analyzed the processing of an intact antigen by purified 26 S proteasome. A recombinant ornithine decarboxylase was produced harboring the H-2K(b)-restricted peptide epitope, derived from ovalbumin SIINFEKL (termed ODC-ova). Utilizing recombinant antizyme to target the antigen to the 26 S proteasome, we found that proteolysis of ODC-ova by the 26 S proteasome resulted in the generation of the K(b)-ligand. Mass spectrometry analysis indicated that in addition to SIINFEKL, the N-terminally extended ligand, HSIINFEKL, was also generated. Production of SIINFEKL was linear with time and directly proportional to the rate of ODC-ova degradation. The overall yield of SIINFEKL was approximately 5% of the amount of ODC-ova degraded. The addition of PA28, the 20 S, or the 20 S-PA28 complex to the 26 S proteasome did not significantly affect the yield of the antigenic peptide. These findings demonstrate that the 26 S proteasome can efficiently digest an intact physiological substrate and generate an authentic MHC class I-restricted epitope.


Subject(s)
Epitopes/metabolism , H-2 Antigens/metabolism , Histocompatibility Antigens Class I/metabolism , Peptide Hydrolases/metabolism , Proteasome Endopeptidase Complex , Protein Processing, Post-Translational , Amino Acid Sequence , Animals , Cell-Free System , Chromatography, High Pressure Liquid , Cloning, Molecular , Ligands , Mice , Mutagenesis, Insertional , Ornithine Decarboxylase/genetics , Ornithine Decarboxylase/metabolism , Ovalbumin/metabolism , Peptide Fragments/chemistry , Peptide Fragments/isolation & purification , Rabbits , Recombinant Proteins/metabolism , Restriction Mapping
10.
Fungal Genet Biol ; 27(1): 88-99, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10413618

ABSTRACT

A gene encoding a developmentally regulated polypeptide of Trichoderma (strain ATCC 32173) was isolated, with the help of an antibody against a 62-kDa protein whose abundance strongly increases during photoinduced sporulation. The amino acid sequence deduced from this gene, cmp1 (conidial multidomain protein), is a 135-kDa polypeptide consisting of several domains. Although reminiscent of known structural modules, two of the domains may define novel families. The protein is apparently processed to give the 62-kDa species. Immunogold labeling electron microscopy localized the antigen to the membrane or inner wall layers. The mRNA is strongly up-regulated during sporulation. At least part of this regulation is likely to be conferred by several elements identified in the upstream region, with homology to elements recognized by fungal transcription factors for regulation by conidiation, light, and nitrogen stress. The developmental regulation, cell surface location, and modular structure suggest a function in cell-cell interactions, detection of the wall by the cell, or anchoring of the plasma membrane to the wall.


Subject(s)
Fungal Proteins/genetics , Genes, Fungal/genetics , Membrane Glycoproteins/genetics , Spores, Fungal/genetics , Trichoderma/genetics , Amino Acid Sequence , DNA, Fungal/chemistry , DNA, Fungal/genetics , DNA, Fungal/isolation & purification , Fungal Proteins/analysis , Fungal Proteins/metabolism , Gene Expression Regulation, Developmental , Gene Expression Regulation, Fungal , Glycosylation , Immunohistochemistry , Mass Spectrometry , Molecular Sequence Data , RNA, Fungal/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Sequence Analysis, DNA , Sequence Homology, Amino Acid , Spores, Fungal/chemistry , Spores, Fungal/ultrastructure , Transcription, Genetic , Trichoderma/chemistry , Trichoderma/ultrastructure
11.
Isr Med Assoc J ; 1(3): 149-53, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10731322

ABSTRACT

BACKGROUND: Acute respiratory distress syndrome is a well-recognized condition resulting in high permeability pulmonary edema associated with a high morbidity. OBJECTIVES: To examine a 10 year experience of predisposing factors, describe the clinical course, and assess predictors of mortality in children with this syndrome. METHODS: The medical records of all admissions to the pediatric intensive care unit over a 10 year period were evaluated to identify children with ARDS. Patients were considered to have ARDS if they met all of the following criteria: acute onset of diffuse bilateral pulmonary infiltrates of non-cardiac origin and severe hypoxemia defined by < 200 partial pressure of oxygen during > or = 6 cm H2O positive end-expiratory pressure for a minimum of 24 hours. The medical records were reviewed for demographic, clinical, and physiologic information including PaO2/forced expiratory O2, alveolar-arterial O2 difference, and ventilation index. RESULTS: We identified 39 children with the adult respiratory distress syndrome. Mean age was 7.4 years (range 50 days to 16 years) and the male:female ratio was 24:15. Predisposing insults included sepsis, pneumonias, malignancy, major trauma, shock, aspiration, near drowning, burns, and envenomation. The mortality rate was 61.5%. Predictors of death included the PaO2/FIO2, ventilation index and A-aDO2 on the second day after diagnosis. Nonsurvivors had significantly lower PaO2/FIO2 (116 +/- 12 vs. 175 +/- 8.3, P < 0.001), and higher A-aDO2 (368 +/- 28.9 vs. 228.0 +/- 15.5, P < 0.001) and ventilation index (43.3 +/- 2.9 vs. 53.1 +/- 18.0, P < 0.001) than survivors. CONCLUSIONS: Local mortality outcome for ARDS is comparable to those in tertiary referral institutions in the United States and Western Europe. The PaO2/FIO2, A-aDO2 and ventilation index are valuable for predicting outcome in ARDS by the second day of conventional therapy. The development of a local risk profile may allow early application of innovative therapies in this population.


Subject(s)
Respiratory Distress Syndrome, Newborn , Acute Disease , Adolescent , Adult , Child , Child, Preschool , Diagnosis, Differential , Female , Humans , Infant , Infant, Newborn , Male , Medical Records , Respiratory Distress Syndrome, Newborn/diagnosis , Respiratory Distress Syndrome, Newborn/etiology , Respiratory Distress Syndrome, Newborn/mortality , Respiratory Distress Syndrome, Newborn/physiopathology , Respiratory Function Tests , Retrospective Studies , Risk Factors , Severity of Illness Index , Survival Analysis
13.
EMBO J ; 17(20): 5964-73, 1998 Oct 15.
Article in English | MEDLINE | ID: mdl-9774340

ABSTRACT

The ubiquitin proteolytic pathway is a major system for selective protein degradation in eukaryotic cells. One of the first steps in the degradation of a protein via this pathway involves selective modification of epsilon-NH2 groups of internal lysine residues by ubiquitination. To date, this amino group has been the only known target for ubiquitination. Here we report that the N-terminal residue of MyoD is sufficient and necessary for promotion of conjugation and subsequent degradation of the protein. Substitution of all lysine residues in the protein did not affect significantly its conjugation and degradation either in vivo or in vitro. In cells, degradation of the lysine-less protein is inhibited by the proteasome inhibitors MG132 and lactacystin. Inhibition is accompanied by accumulation of high molecular mass ubiquitinated forms of the modified MyoD. In striking contrast, wild-type MyoD, in which all the internal Lys residues have been retained but the N-terminus has been extended by fusion of a short peptide, is stable both in vivo and in vitro. In a cell-free system, ATP and multiple ubiquitination are essential for degradation of the lysine-less protein. Specific chemical modifications have yielded similar results. Selective blocking of the alpha-NH2 group of wild-type protein renders it stable, while modification of the internal Lys residues with preservation of the free N-terminal group left the protein susceptible to degradation. Our data suggest that conjugation of MyoD occurs via a novel modification involving attachment of ubiquitin to the N-terminal residue. The polyubiquitin chain is then synthesized on an internal Lys residue of the linearly attached first ubiquitin moiety.


Subject(s)
Lysine/metabolism , MyoD Protein/metabolism , Ubiquitins/metabolism , Adenosine Triphosphate/physiology , Animals , COS Cells , Cells, Cultured , MyoD Protein/chemistry , MyoD Protein/genetics , Peptide Fragments/chemistry , Peptide Fragments/metabolism , Peptide Fragments/physiology , Plasmids/genetics , Radioactive Tracers , Transfection , Ubiquitins/physiology
14.
Pediatr Pulmonol ; 26(2): 125-8, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9727764

ABSTRACT

The purpose of this investigation was to determine the predictive value of the ventilation index (VI) in children with acute respiratory distress syndrome (ARDS). We performed a 10-year retrospective chart review of children who were admitted to the Pediatric Intensive Care Unit with a diagnosis of ARDS. Acute respiratory distress syndrome was defined as acute onset of diffuse, bilateral pulmonary infiltrates of noncardiac origin, and severe hypoxemia, defined as the ratio of the arterial partial pressure of oxygen to the fraction of inspired oxygen of <200 and a positive end expiratory pressure of 6 cmH2O or greater. Records of daily arterial blood gas results and ventilator settings were reviewed, and the ventilation index (VI=partial pressure of arterial CO2 x peak airway pressure x respiratory rate/1,000) was calculated each time the measurements were made. These values were correlated with outcome (survival or nonsurvival). The VI was not different at the time of diagnosis of ARDS in the patients who lived, compared with those who subsequently died. However, by 3 to 5 days after study entry, the VI of nonsurvivors was significantly higher than for survivors (P < 0.05). The VI for survivors remained between 30 and 35 throughout the study period, whereas the VI of nonsurvivors continued to increase with time. A VI of >65 predicted death with a specificity and positive predictive value of >90% on days 3 through 9. We conclude that the VI provides a reliable prognostic marker in children with ARDS, and its increase above 65 indicates a need for orderly intervention with alternative modalities of care.


Subject(s)
Cause of Death , Respiratory Distress Syndrome/diagnosis , Respiratory Distress Syndrome/mortality , Respiratory Function Tests/methods , Adolescent , Analysis of Variance , Blood Gas Analysis , Child , Child, Preschool , Female , Humans , Infant , Intensive Care Units, Pediatric , Israel , Male , Positive-Pressure Respiration , Predictive Value of Tests , Prognosis , Pulmonary Gas Exchange , Respiration , Respiratory Distress Syndrome/therapy , Retrospective Studies , Sensitivity and Specificity , Severity of Illness Index , Survival Rate , Treatment Outcome , Ventilation-Perfusion Ratio
16.
Development ; 115(3): 689-94, 1992 Jul.
Article in English | MEDLINE | ID: mdl-1425348

ABSTRACT

We have recently shown that activin can induce the formation of axial structures from chick blastulae and that activin beta-B is transcribed, in the hypoblast of the chick, at the same stage that axial mesoderm is being induced. It was not clear, however, whether activin was merely allowing the central epiblastic cells to express a differentiated phenotype for which they were already prepared. This report shows that activin-containing medium (ACM) can act as an instructive inductor, which can change the fate of competent cells and bring about the formation of an ectopic embryonic axis. Furthermore, we show data that suggest that during normal development only one axis is obtained as a result of a carefully controlled inhibitory process.


Subject(s)
Blastocyst/drug effects , Embryonic Induction/drug effects , Inhibins/pharmacology , Mesoderm/physiology , Activins , Animals , Chick Embryo , Models, Biological , Morphogenesis/drug effects , Notochord/physiology
17.
Cell ; 63(3): 495-501, 1990 Nov 02.
Article in English | MEDLINE | ID: mdl-2225063

ABSTRACT

We show that PIF/activin can induce the formation of axial structures including a full-length notochord, segmented somites, and a neural tube in isolated epiblasts from chick blastulae. Using degenerate PCR primers, we have cloned a fragment of the activin beta B chain from chick hypoblast cDNA, and a fragment of the activin beta A chain from chick genomic DNA. Furthermore, we show that in the chick, activin is transcribed precisely when axial mesoderm is being induced. Since exogenous PIF/activin can induce the formation of axial structures and since activin beta B is transcribed at the time and place where the mesodermal axial structures are being induced, we propose that in the chick, activin B is the endogenous inducer of the body axis.


Subject(s)
Blastocyst/physiology , Inhibins/physiology , Notochord/physiology , Activins , Amino Acid Sequence , Animals , Base Sequence , Blastocyst/cytology , Chick Embryo , Cloning, Molecular , Inhibins/genetics , Macromolecular Substances , Molecular Sequence Data , Morphogenesis , Notochord/cytology , Oligonucleotide Probes
18.
Development ; 109(2): 387-93, 1990 Jun.
Article in English | MEDLINE | ID: mdl-2401202

ABSTRACT

A chick genomic clone that reveals a high degree of homology to the mammalian and Xenopus bFGF gene has been isolated. The pattern of expression of bFGF has been examined during early chick embryogenesis. RNA blot analysis revealed that chick bFGF is already transcribed at pregastrula stages. Immunolabeling analysis indicated that bFGF protein is present at these early developmental stages and is distributed evenly in the epiblast, hypoblast and marginal zone of the chick blastula. Substances that can inhibit FGF action were applied to early chick blastoderms grown in vitro under defined culture conditions (DCM). Both heparin and suramin were capable of blocking the formation of mesodermal structures in a dose-dependent manner. Our results indicate that FGF-like substances may need to be present for axial structures to develop although they may be acting earlier during the induction of non-axial mesoderm.


Subject(s)
Cell Differentiation/genetics , Embryonic Induction/genetics , Fibroblast Growth Factors/genetics , Mesoderm/physiology , Amino Acid Sequence , Animals , Base Sequence , Chick Embryo , Genomic Library , Heparin/pharmacology , Mesoderm/drug effects , Molecular Sequence Data , Suramin/pharmacology , Transcription, Genetic
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