Biomedical subjects

E Jung

Publications and source records attributed to E Jung.

At least 19 recordsLinked to original sources

PubMed1999

1,25-dihydroxyvitamin D3 induces phospholipase D-1 expression in primary mouse epidermal keratinocytes.

The hormone 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) elicits the programmed pattern of differentiation in epidermal keratinocytes. Based on data indicating a potential role of phospholipase D (PLD) in mediating keratinocyte differentiation, we investigated the effect of 1,25(OH)2D3 on PLD expression. A 24-h exposure to 1, 25(OH)2D3 stimulated PLD-1, but not PLD-2, mRNA expression. This 1, 25(OH)2D3-enhanced expression was accompanied by increased total PLD and PLD-1 activity. Time course studies indicated that 1,25(OH)2D3 induced PLD-1 expression by 8 h, with a maximal increase at 20-24 h. Exposure to 1,25(OH)2D3 inhibited proliferation over the same time period with similar kinetics. Expression of the early (spinous) differentiation marker keratin 1 decreased in response to 1, 25(OH)2D3 over 12-24 h. Treatment with 1,25(OH)2D3 enhanced the activity of transglutaminase, a late (granular) differentiation marker, by 12 h with a maximal increase after 24 h. In situ hybridization studies demonstrated that the highest levels of PLD-1 expression are in the more differentiated (spinous and granular) layers of the epidermis, with little expression in basal keratinocytes. Our results suggest a role for PLD expression/activity during keratinocyte differentiation.

Animals↗

PubMed1999

Scanning the available Dictyostelium discoideum proteome for O-linked GlcNAc glycosylation sites using neural networks.

Dictyostelium discoideum has been suggested as a eukaryotic model organism for glycobiology studies. Presently, the characteristics of acceptor sites for the N-acetylglucosaminyl-transferases in Dictyostelium discoideum, which link GlcNAc in an alpha linkage to hydroxyl residues, are largely unknown. This motivates the development of a species specific method for prediction of O-linked GlcNAc glycosylation sites in secreted and membrane proteins of D. discoideum. The method presented here employs a jury of artificial neural networks. These networks were trained to recognize the sequence context and protein surface accessibility in 39 experimentally determined O-alpha-GlcNAc sites found in D. discoideum glycoproteins expressed in vivo. Cross-validation of the data revealed a correlation in which 97% of the glycosylated and nonglycosylated sites were correctly identified. Based on the currently limited data set, an abundant periodicity of two (positions-3, -1, +1, +3, etc.) in Proline residues alternating with hydroxyl amino acids was observed upstream and downstream of the acceptor site. This was a consequence of the spacing of the glycosylated residues themselves which were peculiarly found to be situated only at even positions with respect to each other, indicating that these may be located within beta-strands. The method has been used for a rapid and ranked scan of the fraction of the Dictyostelium proteome available in public databases, remarkably 25-30% of which were predicted glycosylated. The scan revealed acceptor sites in several proteins known experimentally to be O-glycosylated at unmapped sites. The available proteome was classified into functional and cellular compartments to study any preferential patterns of glycosylation. A sequence based prediction server for GlcNAc O-glycosylations in D. discoideum proteins has been made available through the WWW at http://www.cbs.dtu.dk/services/DictyOGlyc/ and via E-mail to DictyOGlyc@cbs.dtu.dk.

Algorithms↗

PubMed1998

Rules for the addition of O-linked N-acetylglucosamine to secreted proteins in Dictyostelium discoideum--in vivo studies on glycosylation of mucin MUC1 and MUC2 repeats.

One class of O-glycosylation in the simple eukaryote Dictyostelium discoideum involves the addition of a single N-acetylglucosamine residue to Ser and Thr residues on secreted or membrane-bound proteins at an early stage of development. A previously developed in vivo approach for the identification of acceptor sites for O-glycosylation was used to further characterise the specificity of the UDP-GlcNAc :polypeptide N-acetylglucosaminyltransferase(s). Glutathione S-transferase fusion proteins were constructed to express and secrete the mucin peptide repeat for MUC1 (PDT1RPAPGS1T2APPAHGVT3S2A) and a MUC2-like peptide (PT1T2T3PIT4T5T6T7T8T9VT10PT11PT12PT13GT14QT15), respectively (superscript numbers indicate residues with the potential to be glycosylated). Monosaccharide analysis, electrospray-ionisation mass spectrometry and protein sequencing showed that the modification is a single N-acetylglucosamine attached to certain Thr residues. The MUC1 repeat was glycosylated on T2 and T3 and there were no modifications on T1 or on S1 and S2. The MUC2 glycopeptide was glycosylated on T1, T3, T5, T7, T9, T10, T11, T12, T13 and T14. Our results show that the D. discoideum glycosylation apparatus incorporates GlcNAc residues into peptide sequences similar to those reported for the addition of GalNAc residues in mammalian tissues. The anomeric linkage of the GlcNAc residues to the polypeptide chain was shown to be in alpha configuration as determined by NMR studies.

Acetylglucosamine↗

PubMed1998

Sustained phospholipase D activation in response to angiotensin II but not carbachol in bovine adrenal glomerulosa cells.

We have demonstrated previously that in bovine adrenal glomerulosa cells, phospholipase D (PLD) activity can indirectly result in the generation of sn-1,2-diacylglycerol (DAG) through its production of phosphatidic acid (PA) and the subsequent action of PA phosphohydrolase. Furthermore, the PLD-generated DAG can trigger aldosterone secretion. Therefore, we characterized PLD activation by two agonists, angiotensin II (Ang II) and carbachol, to determine if the activity of the enzyme might underlie sustained aldosterone secretion. We determined that Ang II-induced PLD activation occurred via the angiotensin-1 receptor (AT1), and that a specific AT1 antagonist, losartan, inhibited this activation, whereas the same concentration of the AT2-specific antagonist, PD 123319, had no effect. Ang II activated PLD with a dose dependence similar to that observed for aldosterone secretion, with slight increases in activity induced by 0.1 nM Ang II and maximal activation at 10 nM. We also found that Ang II induced a sustained activation of PLD, but that the effect of carbachol, a stable analogue of acetylcholine, was transient; PLD activity increased within 5 min of exposure to carbachol but then ceased by 15 min. Higher carbachol concentrations were also unable to sustain PLD activation. These results suggest that the Ang II-elicited activation of PLD is associated with a sustained increase in aldosterone secretion from glomerulosa cells and further provide the first evidence, to our knowledge, of differences in the kinetics of PLD activation in response to two physiologically relevant agonists. Finally, we speculate that this disparity correlates with different functional responses induced by the two agents.

Angiotensin II↗

PubMed1998

Complement component C9 enhances the capacity of beta-lactam antibiotics to kill Escherichia coli in vitro and in vivo.

Complement component C9 is required for rapid complement-mediated killing of Escherichia coli. In this report, the influence of supplemental C9 on the bactericidal and protective effects of beta-lactam antibiotics in neonates was assessed. By rocket immunoelectrophoresis, the intrinsic C9 concentrations of pooled serum from both human and rat neonates was less than 20% of adult levels. Supplemental C9 purified from human plasma enhanced the capacity of ampicillin-treated serum from human neonates to impair the survival of E coli O7:K1:NM (P < 0.02). Similarly, supplemental C9 enhanced the capacity of cefotaxime-treated neonatal rat serum to impair the survival of E coli O1:K1:NM (P < 0.05). Moreover, the intraperitoneal administration of C9 enhanced the survival of cefotaxime-treated neonatal rats that were septic with E coli (P < 0.05). These observations may contribute to the development of new strategies, such as augmentation of complement component serum concentrations, to reduce the morbidity and mortality of neonatal E coli sepsis.

Adult↗

PubMed1997

An in vivo approach for the identification of acceptor sites for O-glycosyltransferases: motifs for the addition of O-GlcNAc in Dictyostelium discoideum.

To identify and analyze acceptor sequences for O-glycosylation, we have developed an in vivo system expressing short peptides as glutathione S-transferase fusion proteins in the eukaryotic host Dictyostelium discoideum. Using this approach, we show that a short peptide motif (PTVTPT), present in the D. discoideum cell-surface glycoprotein PsA, is sufficient as a signal for O-glycosylation, even when fused to a heterologous protein. Monosaccharide analysis and solid-phase protein sequencing showed that the modification is a single N-acetylglucosamine attached to threonine residues. This was further confirmed by electrospray-mass spectrometry. The O-linked glycosylation of both this peptide and authentic PsA presents the modB-dependent carbohydrate-specific epitope identified by the monoclonal antibody MUD50. Substitution of threonine by serine residues in this peptide also yields a glycosylated fusion protein which is modified with single N-acetylglucosamine residues, but not all of the serines are glycosylated.

Acetylglucosamine↗

PubMed1997

The production of recombinant glycoproteins with special reference to simple eukaryotes including Dictyostelium discoideum.

Because many recombinantly produced proteins require post-translational modification to be properly folded and active, there is a new emphasis on eukaryotic expression systems. Dictyostelium discoideum is a well studied eukaryotic model organism for the investigation of key questions in molecular and cell biology. More recently D. discoideum was successfully used as a system for recombinant glycoprotein production. The vegetative amoebae are easy and inexpensive to grow either in axenic culture or on Gram-negative bacteria. Reliable and uncomplicated transformation systems are also well established. This organism harbours the machinery to perform post-translational modifications such as phosphorylation, acylation, formation of glycosylphosphatidylinositol anchors and more importantly N- and O-linked glycosylation. This review provides an overview of glycosylation in different expression systems and focuses on glycosylation in D. discoideum.

Animals↗

PubMed1997

The administration of complement component C9 enhances the survival of neonatal rats with Escherichia coli sepsis.

To determine the significance of neonatal C9 deficiency, an animal model was developed in the rat. By rocket immunoelectrophoresis, the concentration of C9 in pooled adult rat serum was 224 +/- 7.2 microg/mL. In contrast, the concentration of C9 in pooled serum from 1-d-old rats was only 43 +/- 3.8 microg/mL and increased during the first 3 wk of life to 170 +/- 20 microg/mL. Similarly, the capacities of neonatal rat serum to kill two pathogenic strains of Escherichia coli and to lyse sensitized sheep erythrocytes were diminished compared with adult serum but increased during the first 3 wk of life. Supplemental human C9 significantly enhanced the bactericidal and hemolytic activity of neonatal rat serum. The capacity of neonatal rats to survive after the intrapulmonary injection of E. coli was positively correlated with the serum C9 concentration, bactericidal activity, and hemolytic activity. In 2-d-old rats infected with E. coli, the intraperitoneal administration of human C9 significantly enhanced survival and also enhanced the protective effect of intraperitoneal human IgG antibodies. The data indicate that C9 deficiency predisposed neonatal rats to invasion by E. coli. The neonatal rat appears to be a suitable model with which to investigate the significance of C9 deficiency.

Age Factors↗

PubMed1997

[A successful surgical case report of acute aortic dissection involving entire sinus of Valsalva].

We successfully performed aortic root replacement for acute aortic dissection, Stanford type A involving the entire sinus of Valsalva, associated with acute anterior wall myocardial infarction and aortic valve insufficiency. A 57-year-old man was admitted complaining of chest pain. An emergency operation was performed after a perfusion catheter was inserted to 99% stenotic lesion of the left anterior descending artery (LAD) on the same day. The dissection extended to both ostia of the coronary arteries and disrupted all commissures of the aortic valve, resulting in severe prolapse of the aortic valve leaflets. Aortic root replacement was performed using a valved conduit. The left main coronary artery was reattached to the graft using interposition technique with a 8 mm diameter woven Dacron tube graft. In addition, the LAD and right coronary artery were bypassed using saphenous vein. The postoperative course was uneventful and the patient was discharged from hospital on the 35th postoperative day. Retaining no aortic sinus and adequate coronary artery reconstruction is important for surgical repair of aortic dissection involving the entire sinus portion of the ascending aorta.

Aortic Dissection↗

PubMed1997

[Acute pancreatitis and ectopic pancreas].

We report the case of a 28-year-old woman with a pancreatic heterotopia presenting with a history of acute pancreatitis. Symptoms were epigastric pains. Abdomino-pelvic CT Scan revealed a tumor located in gastro-duodenal area. Exploratory surgery was performed, and the segment containing the mass was resected. Histopathologic examination of the lesion revealed heterotopic pancreatic tissue without malignancy.

Acute Disease↗

PubMed1996

Linking microfilaments to intracellular membranes: the actin-binding and vesicle-associated protein comitin exhibits a mannose-specific lectin activity.

Comitin is a 24 kDa actin-binding protein from Dictyostelium discoideum that is located primarily on Golgi and vesicle membranes. We have probed the molecular basis of comitin's interaction with both actin and membranes using a series of truncation mutants obtained by expressing the appropriate cDNA in Escherichia coli. Comitin dimerizes in solution; its principle actin-binding activity is located between residues 90 and 135. The N-terminal 135 'core' residues of comitin contain a 3-fold sequence repeat that is homologous to several monocotyledon lectins and which retains key residues that determine these lectins' three-dimensional structure and mannose binding. These repeats of comitin appear to mediate its interaction with mannose residues in glycoproteins or glycolipids on the cytoplasmic surface of membrane vesicles from D.discoideum, and comitin can be released from membranes with mannose. Our data indicate that comitin binds to vesicle membranes via mannose residues and, by way of its interaction with actin, links these membranes to the cytoskeleton.

Actin Cytoskeleton↗

PubMed1996

Nephrotic syndrome, hypertension, and adrenal failure in atypical Cockayne syndrome.

This report describes a boy with an atypical severe from of Cockayne syndrome type II manifesting in infancy. He developed nephrotic syndrome at the age of 4.7 years and a hypertensive crisis with hemiparesis at 5.4 years. Renal biopsy revealed focal segmental glomerulosclerosis, which was confirmed at autopsy. Adrenocortical failure was also present. The course was characterized by frequent infections and an episode of myocarditis. The boy died at the age of 6.0 years after rapid neurological deterioration accompanied by renal insufficiency. Autopsy disclosed cerebral leukodystrophy compatible with Cockayne syndrome.

Adrenal Cortex Diseases↗

PubMed1996

[Carcinoma in situ of the breast--is axillary lymphadenectomy necessary?].

Between 1963 and 1993, 3720 women were treated both at the Universitäts-Frauenklinik Berlin-Charlottenburg and at the I. Frauenklinik der Universität München for a malignant condition of the breast. 187 of these (5%) exhibited stage p Tis, 102 (54.5%) of whom had an axillary lymphadenectomy. One patient had a micrometastasis (pN1a). During the observation period of up to 24 years, 11 patients (5.9%) developed local recurrence. In none of the patients a regional or generalised recurrence could be observed within this period. On the basis of our own results and those from the literature, we conclude that, under the aspect of a risk-adapted tumour surgery, axillary lymphadenectomy is no longer necessary under certain conditions: an invasive carcinoma should be excluded with high certainty in the tumourectomy specimen as well as in the remaining breast. Therefore, a histological work-up in serial sections must be provided to exclude multifocality (multicentricity) and a tumour diameter larger than 25 mm.

Adult↗

PubMed1996

Prognostic value of tuberculin and BCG immunoreactivity in stage I high-risk malignant melanoma (EORTC protocol 18781).

BACKGROUND: Since the immune system is considered to be a major determinant in the outcome of malignant melanoma, vaccination with BCG (bacillus Calmette-Guérin) or more recently with interleukins is used in this condition, although the effects of this immunotherapy are unclear. OBJECTIVE: The present study was to elucidate clinical aspects and the prognostic relevance of the cellular and humoral immune responses of melanoma patients treated with two different BCG vaccines. METHODS: A subgroup of patients from a multicenter adjuvant trial with BCG in stage I (pT3-4N0M0) high-risk melanoma was prospectively subjected to detailed analysis regarding tuberculin (PPD, purified protein derivate) skin test reactivity, local, regional and systemic reactions to BCG vaccination, PPD antibody response and disease-free survival. Patients were randomized into three arms and received either no adjuvant treatment (22 patients), BCG RIV (40 patients) or BCG Pasteur (44 patients). All patients were followed for up to 10 years (median follow-up 6 years). RESULTS: Patients treated with BCG Pasteur mounted a stronger antibody response, experienced stronger regional and systemic reactions to vaccination and converted more frequently to positive PPD skin tests, compared to controls and to patients vaccinated with BCG RIV. All BCG-treated patients who developed an antibody response had a longer disease-free interval (p = 0.05), with slightly higher significance for BCG Pasteur-treated patients (p = 0.02). CONCLUSIONS: Cellular as well as humoral immune responses to PPD and BCG thus identify stage I malignant melanoma patients with an overall better prognosis.

Adolescent↗

PubMed1996

Intraductal carcinoma (DCIS) of the breast. Risk-adapted tumor surgery with axillary lymphadenectomy?

Between 1963 and April 1994, 3823 women were treated both at the Universitäts-Frauenklinik Berlin-Charlottenburg as well as at the I. Frauenklinik der Universität München, for a malignant condition of the breast gland. 161 of these (4.2%) exhibited an intraductal carcinoma stage pTis, whilst 99 (61.5%) were axillary lymphadenectomised. During the observation time-span of up to 24 years, 9 patients (5.6%) developed local recurrence. In neither patients of the group with axillary nor without axillary dissection could a regional recurrence be observed within this period. Also, a generalisation of this condition was not recorded in any patient. On the basis of our own results and those from the literature we postulate that, under the auspices of a risk adapted tumor surgery, axillary lymphadenectomy is no longer necessary under certain conditions in non-invasive breast carcinoma.

Adult↗

PubMed1995

[A successful circulatory assist in acute left heart failure after a rapid two-stage arterial switch operation].

A 6-month-old female with transposition of the great arteries with intact ventricular septum successfully survived with the aid of a circulatory assist device for acute left heart failure after rapid two stage-arterial switch operation (ASO). The interval between pulmonary artery banding and ASO was 9 days. Left heart failure appeared immediately after ASO, so we started the circulatory assist with a centrifugal pump. The left ventricular function gradually recovered. After 43 hours assisted circulation, she was successfully weaned from the pump. Subsequent recovery was uneventful and the patient was discharged from the hospital on the 40th postoperative day. In case of acute left heart failure after ASO due to sudden changes in the left ventricular afterload, adaptation of the left ventricle can be expected by a relatively short period of circulatory assist with centrifugal pump.

Acute Disease↗

PubMed1995

[Two cases of successful arterial switch operation for double outlet right ventricle associated with straddling and cleft mitral valve].

We successfully performed an anatomical repair for double outlet right ventricle associated with straddling and cleft mitral valve in two patients. In both patients position of the anterior and posterior papillary muscles was found to be normal. Therefore, all staddled mitral component was detached. The mitral valve competency was achieved by suture-closure of the cleft and annuloplasty. This procedure facilitated intraventricular re-routing from the left ventricle to the pulmonary artery. Then arterial switch was performed. Postoperative course was uneventful and no significant mitral valve regurgitation was found in either patient postoperatively. This procedure can be a good option in patients with double outlet right ventricle associated with straddling mitral valve.

Child, Preschool↗

PubMed1995

The smart card: an ideal tool for a computer-based patient record.

Over the past decades, technology has advanced in all areas. Medical documentation, however, has not altered considerably. This means that medical care is often below standard. This article tries to point out how healthcare could benefit from a computer-based medical record. It also discusses the use of a medical smart card as a computer-based patient record--exemplified by the European DIABCARD-project which develops a chip card for persons with diabetes.

Computer Security↗