Biomedical subjects

M Schmidt

Publications and source records attributed to M Schmidt.

At least 415 records · Page 23Linked to original sources

PubMed1997

Identification of G protein-coupled receptors potently stimulating migration of human transitional-cell carcinoma cells.

The expression of G protein-coupled receptors inducing calcium mobilization and stimulating cell migration was examined in human transitional-cell carcinoma (J82) cells. Measurements of cytoplasmic Ca2+ concentration ([Ca2+]i) and phospholipase C activity indicated that these cells express several calcium-mobilizing receptors, including those for lysophosphatidic acid (LPA), thrombin, bradykinin, bombesin and histamine, of which only the LPA response was sensitive (approximately 50%) to pertussis toxin (PTX). Migration of J82 cells was strongly stimulated by LPA and thrombin, by 5- to 20-fold, whereas bradykinin, bombesin and histamine were ineffective. Migration induced by either LPA or thrombin was inhibited by the actin cytoskeleton-disrupting agent, cytochalasin B, by the Rho protein-inactivating Clostridium difficile toxin B, by preventing [Ca2+]i transients with an intracellular calcium-chelating agent, and by the phorbol ester, phorbol 12-myristate 13-acetate, which also blocked the LPA- and thrombin-induced [Ca2+]i increases. On the other hand, ADP-ribosylation of Gi type G proteins by PTX abrogated the migratory response to LPA, without affecting the thrombin effect. Similarly, raising cAMP levels inhibited, by about 50%, the LPA- but not the thrombin-induced J82 cell migration. In conclusion, human transitional-cell carcinoma (J82) cells express various G protein-coupled, calcium-mobilizing receptors, out of which only those for LPA and thrombin stimulate cell migration, indicating that phospholipase C-derived second messengers per se are not sufficient for initiating this response. The complex signal transduction processes leading to LPA- and thrombin-stimulated motility of these human carcinoma cells apparently involve several common, essential factors, such as [Ca2+]i changes and Rho protein-regulated reorganization of the cytoskeleton, as well as some distinct components, most notably distinct subtypes of heterotrimeric G proteins and apparently also distinct cAMP-sensitive targets.

Calcium↗

PubMed1997

Evidence of alternative promoters directing isoform-specific expression of human endothelin-converting enzyme-1 mRNA in cultured endothelial cells.

The endothelins, a family of closely related vasoactive and mitogenic peptides, are thought to play an important role in cardiovascular pathophysiology. The conversion of the inactive precursor "big endothelin" to the biologically active peptide is catalyzed in vitro and in vivo by endothelin-converting enzymes (ECE). Recently the cDNA cloning of two homologous proteins, termed ECE-1 and ECE-2, has been reported. ECE-1 may play a key role in the activation and regulation of the cardiovascular endothelin proteolytic cascade. ECE-1 mRNA is expressed in two isoforms, termed alpha and beta, which are identical except for the 5'-terminal regions. To investigate the transcriptional regulation of isoform-specific ECE-1 mRNA expression we isolated phage clones from a human genomic library and identified the alpha- and beta-specific exons of ECE-1. The exon/intron organization of the 5'-terminal region of the human ECE-1 gene in conjunction with putative transcription initiation start sites suggests the existence of two alternative promoters, each directing the expression of either isoform. A reverse transcription/polymerase chain reaction assay indicated differential mRNA expression of ECE-1 isoforms. Using a luciferase reporter gene assay, we found that the genomic region upstream of exon 1 alpha confers strong promoter activity in the human endothelial cell line ECV 304, which was previously shown to express predominantly ECE-1 alpha mRNA. Transfection of serial deletion mutants in ECV304 cells indicated the existence of three positive and also one negative regulating element within 2 kb of the alpha-promoter region. Luciferase reporter gene studies also revealed that the genomic region upstream of exon 3, which encodes the putative ECE-1 beta specific N-terminus, was able to direct luciferase expression in primary cultured bovine aortic endothelial cells, indicating the existence of an alternative promoter. Transfection of nested deletions spanning 1.2 kb upstream of the putative translation initiation codon of ECE-1 beta suggested the existence of three positive regulating regions within the beta-specific promoter. Both ECE-1 promoters lack TATA or CAAT boxes, and the two show different patterns of consensus sequences for transcription factors, suggesting a differential transcriptional regulation of isoform-specific ECE-1 mRNA expression.

Aspartic Acid Endopeptidases↗

PubMed1997

[Standardized aerobic walking on the treadmill by healthy probands and patients with mitochondrial and non-mitochondrial myopathies].

Mitochondrial myopathies are characterized by an abnormal aerobic metabolism. The present study examines the serum lactate concentration during standardized aerobic treadmill ergometry and evaluates its relevance for the diagnosis of mitochondrial myopathies. The present study includes 50 volunteers without neuromuscular disorders (control group), 13 patients with mitochondrial, and 14 patients with non-mitochondrial neuromuscular disorders. All members of the control group were able to walk 15 minutes on the treadmill at a constant velocity of at least 5 km/h without exceeding the aerobic threshold (2 mMol/l lactate, venous blood). Ten patients with mitochondrial myopathies and 4 patients with non-mitochondrial myopathies already exceeded the aerobic threshold at walking velocities of 4 or 5 km/h. Though indicating a reduced aerobic endurance, a pathological test result does not prove the diagnosis of a mitochondrial myopathy. Sensitivity and specificity of treadmill ergometry did not differ significantly from those reported for bicycle ergometry. Thus, using the most common aerobic activity in daily life, treadmill ergometry can be considered as an alternative to bicycle exercise tests in the assessment of mitochondrial abnormalities.

Adult↗

PubMed1997

[Value of contrast-enhanced 3D magnetic resonance angiography of the renal arteries].

PURPOSE: To determine the value of gadolinium-enhanced, three-dimensional breath-hold Magnetic Resonance Angiography (MRA) in the assessment of the aorta and renal arteries in comparison to conventional arteriography (CA). PATIENTS AND METHODS: 49 patients were evaluated with both CA and 3D MRA. 0.3 mmol/kg BW gadolinium-DTPA was administered intravenously in a bolus, using an automated injector. A test bolus method was used for timing of the bolus and beginning of the data acquisition. The intraarterial CA was used as the gold standard. RESULTS: MRA-based assessment of renal artery stenosis was identical with CA in 31 of 45 stenoses (68.8%). Sensitivity and specificity for assessment of renal arterial disease by MRA were 84% and 96%; for clinically relevant lesions they amounted to 90% and 98%. CONCLUSION: The presented contrast-enhanced 3D MRA technique allows for the reliable assessment of renal arterial morphology and pathology.

Adult↗

PubMed1997

Immunocytochemical analysis of glomerular regionalization and neuronal diversity in the olfactory deutocerebrum of the spiny lobster.

Antibodies against serotonin, dopamine, FMRF amide, substance P, and molluscan small cardioactive peptide (SCPB) were used to differentiate glomeruli and neurons in the olfactory deutocerebrum of the spiny lobster, Panulirus argus. Immunoreactivity to these antibodies identified distinct regions within individual columnar glomeruli of the olfactory lobe (OL), but not within the spherical glomeruli of the accessory lobe (AL). Glomeruli in the lateral, central, and medial layers of the AL, however, had different patterns of immunoreactivity. The immunostainings differentiated six types of local interneurons and three types of centrifugal projection neurons. Local interneurons included: (1) a "dorsal giant" neuron with serotonin- and FMRF amide-like immunoreactivity arborizing in most or all glomeruli of the OL, in the glomeruli of the medial and lateral layer of the AL and in the unstructured olfactory globular tract neuropil, (2) three large OL "core" neurons, two with serotonin-like and one with FMRF amide-like immunoreactivity innervating many OL glomeruli, (3) several hundred small, globuli-type OL "core" neurons with serotonin- and FMRF amide-like immunoreactivity, (4) thousands of small, globuli-type neurons with FMRF amide- and/or substance P-like immunoreactivity connecting the OL with the central layer of the AL, (5) thousands of small, globuli-type AL interneurons with substance P like immunoreactivity and additional arborizations in the unstructured deutocerebral tract neuropil, and (6) many small, globuli-type OL "rim" neurons with FMRF amide- and/or SCPB-like immunoreactivity. Centrifugal projection neurons included two that targeted the soma clusters and a pair of large neurons with dopamine-like immunoreactivity that originated in the lateral protocerebrum and arborized in the OL and AL glomeruli. Only few ascending projection neurons and no olfactory afferents were labeled. These results suggest that in the spiny lobster neurochemically distinct subpopulations of local interneurons constitute functionally distinct regions within individual OL glomeruli and across groups of AL glomeruli.

Animals↗

PubMed1997

Endometrial integrin expression is independent of estrogen or progestin treatment in vitro.

OBJECTIVE: To examine the regulation of endometrial integrin expression by estrogens and progestins in vitro. DESIGN: Immunocytochemical study. SETTING: Academic research unit. PATIENT(S): Twenty-five regularly cycling women without endometrial pathology, of whom seven had endometriosis. INTERVENTION(S): Endometrial cells obtained by aspiration curettage were treated with diethylstilbestrol, promegestone, and antiprogestin. Immunocytochemistry was performed with antibodies directed against integrins alpha 1 beta 1, alpha 2 beta 1, alpha 4 beta 1, alpha 5 beta 1, alpha v beta 3, and beta 3 integrin subunit. MAIN OUTCOME MEASURE(S): Semiquantitative staining score. RESULT(S): Endometrial cells express several integrins in vitro in a consistent and cell specific pattern. Neither differences between treated and untreated cells nor an effect of treatment duration or dosage were observed. Cells from patients with and without endometriosis showed similar patterns. CONCLUSION(S): The cellular distribution of integrin expression was similar to that described in vivo. In contrast, a steroid regulated expression could not be detected in vitro. Rather, a derepression by a factor not included in our model could be responsible for the cyclic appearance of some integrins. In endometriosis, no fundamental difference of integrin expression was detected.

Cells, Cultured↗

PubMed1997

Regulation of phospholipase C and D activities by small molecular weight G proteins and muscarinic receptors.

The role of small molecular weight guanine nucleotide-binding proteins (G proteins) of the Rho family in muscarinic acetylcholine receptor (mAChR) signaling to phospholipase C (PLC) and phospholipase D (PLD) was studied in human embryonic kidney (HEK) cells, stably expressing the human m3 receptor subtype. Evidence for the involvement of Rho proteins in m3 mAChR signaling to both phospholipases is based on findings obtained with Clostridium (C.) difficile toxin B and C. botulinum C3 exoenzyme, both of which specifically, although by different mechanisms, inactivate Rho family G proteins. Toxin B potently inhibited both the mAChR-stimulated PLC and PLD activities in intact cells as well as the stimulation of both phospholipases by the stable GTP analog GTPgammaS in permeabilized cells, the latter effect being mimicked by C3 exoenzyme. In contrast, PLC and PLD activities, measured in the presence of exogenous phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2], a substrate and cofactor for PLC and PLD, respectively, were not altered. These data suggested that the Rho-inactivating toxins inhibit stimulation of PLC and PLD by reducing the cellular level of PtdIns(4,5)P2, which was indeed found with both toxin B and C3 exoenzyme. In agreement with a crucial role of cellular PtdIns(4,5)P2 supply for PLC signaling, we observed that short-term agonist (carbachol) treatment of HEK cells caused a long-lasting increase in PtdIns(4,5)P2 level, accompanied by a potentiation of receptor- and G protein-stimulated inositol phosphate formation. Finally, studies with tyrosine kinase and tyrosine phosphatase inhibitors strongly suggest that PtdIns(4,5)P2 synthesis and mAChR-stimulated PLD activity in HEK cells apparently also involve a tyrosine phosphorylation-dependent mechanism(s). Thus, m3 mAChR signaling to PLC and PLD in HEK cells requires the concerted action of various intracellular components, most notably the complex regulation of PtdIns(4,5)P2 synthesis.

Cell Line↗

PubMed1997

The influence of time of insemination relative to time of ovulation on farrowing frequency and litter size in sows, as investigated by ultrasonography.

The objective of this experiment was to identify the optimal time of insemination relative to the time of ovulation, based on ultrasonographic detection of embryonic survival at 10 days after ovulation, number of sows farrowing, and litter size. Furthermore, the possible value of the interval from weaning to onset of estrus for prediction of the time of ovulation was examined. Crossbred sows (n = 143) that had farrowed 2 to 9 litters were weaned (Day 0) and observed for estrus every 8 h from Day 3 until end of estrus. Ultrasonography was performed every 6 h, from 12 h after onset of estrus until ovulation had been observed. The sows were inseminated once at various time intervals from ovulation. At Day 16, 25 of the sows were slaughtered and their uteri were flushed for embryos. In the remaining sows, the number of viable and dead piglets and mummified fetuses per sow was recorded at farrowing, with the sum of the 3 constituting the total number of piglets born per sow. The highest number of embryos recovered per sow was found after insemination during the interval from 24 h before to 4 h after ovulation. The lowest frequency of non-pregnant sows and the highest total number of piglets born per sow were found after insemination from 28 h before to 4 h after ovulation. Consequently, the optimal time for insemination was found to be in the interval 28 h before to 4 h after ovulation. The interval from weaning to onset of estrus and from onset of estrus to ovulation were negatively correlated, allowing a rough prediction of the time of ovulation from the interval from weaning to onset of estrus.

Journal Article↗

PubMed1997

Immunological reactivity of baculovirus-expressed enterovirus proteins.

In order to study immunological reactivity of individual enterovirus polypeptides and evaluate their usefulness for enterovirus diagnosis, the genes coding for viral structural and nonstructural proteins were expressed using recombinant baculoviruses. A histidine-tailed coxsackievirus B3 (CBV3) VP1 capsid protein was expressed and purified by immobilized metal ion affinity chromatography for EIAs. To elucidate the usefulness of the other CBV3 capsid proteins for immunoassays, recombinant baculovirus expressing the whole CBV3 capsid polyprotein region was constructed. For the detection of a potentially broader spectrum of enteroviruses, the conserved nonstructural P3 region was expressed. The P3 region encodes four nonstructural proteins including a cysteine protease (3C) and an RNA-dependent RNA-polymerase (3D). The 3C polypeptide was shown to be proteolytically active indicating that the baculovirus system is capable of expressing biologically functional enterovirus proteins. Immunoblot analysis detected antibodies against the VP1, 3C and 3D proteins in human serum samples. When the baculovirus-expressed antigens were compared with lysates of enterovirus-infected cells and a synthetic peptide in EIA highly similar results were obtained with recombinant VP1 and the lysate antigens. Although reactive in immunoblots, the P3 encoded proteins were not satisfactory for EIA.

Baculoviridae↗

PubMed1997

Birth and prematurity influence intestinal function in the newborn pig.

Developmental changes in intestinal function occur in the perinatal period of many species. We investigated the hypothesis that gestational age at delivery and the mode of delivery influence intestinal function. Newborn pigs (106-108 or 113-115 days gestation, term = 115 +/- 2 days) were either delivered by caesarean section or born vaginally following induction of parturition with a prostaglandin F2 alpha analogue. The pigs were killed at birth and used for measurements of intestinal ion transport in vitro (using Ussing chambers) or killed at 2 days of age, after being fed porcine colostrum to follow the absorption of intact proteins into plasma. The results indicate that premature birth is associated with increased paracellular permeability to ions. The uptake and net absorption of chloride were higher in the term, vaginally-delivered pigs than in the remaining pigs. Among the newborn pigs, the preterm caesarean-delivered pigs exhibited the lowest chloride secretion in response to the secretagogue, theophylline. The latter pigs also absorbed the lowest amounts of immunoglobulin G and albumin from colostrum. In conclusion, gestational age at delivery and the mode of delivery have significant effects on intestinal transport of ions and intact proteins. However, the observed variation in the magnitude and the direction of responses indicate that (a) prematurity and birth influence the transport of ions and intact proteins through independent regulatory mechanisms and (b) the absorption pathways for ions and intact proteins in the neonatal pig intestine are not closely associated.

Animals↗

PubMed1997

Intravenous dextroamphetamine and brain glucose metabolism.

This study reports the effects of intravenous dextroamphetamine on cerebral glucose metabolism assayed by positron emission tomography (PET) and [fluorine-18]fluorodeoxyglucose (FDG) in 13 healthy adults during the performance of a continuous visual attention task. Two FDG PET scans were performed within a single experimental session. The first scan was preceded by the injection of placebo and the second scan by the injection of 0.15 mg/kg dextroamphetamine. Global and normalized regional glucose metabolic rates (rCMRglc) were examined as a function of pharmacological challenge and subjective experience. Subcortical, limbic, frontal, and cerebellar rCMRglc significantly increased after dextroamphetamine, whereas rCMRglc of the temporal cortex significantly decreased. Physiological and self-report measures of subjective states showed the expected alterations. These rCMRglc changes reflect both the direct pharmacological effect of dextroamphetamine on monoaminergic neurotransmitter systems as well as enhancement of the activation of the neural network mediating the performance of the continuous attention task.

Adult↗

PubMed1997

RU486 is a potent inhibitor of aromatase induction in human breast adipose tissue stromal cells.

Aromatization of circulating androgens in adipose tissue is a major source of estrogens in postmenopausal women. As part of our efforts to elucidate the mechanism of aromatase induction in human breast adipose tissue, we tested the effects of the antiglucocorticoid and antiprogestin, RU486, on aromatase induction in primary cultures of adipose tissue stromal cells in a serum-free system devoid of phenol-red. Under these conditions 1 microM cortisol alone induces low levels of aromatase activity within one day, whereas platelet-derived growth factor BB (PDGF) potentiates this effect two- to three-fold. The well-known strong inductive effect of dibutyryl-cAMP (db-cAMP) is also augmented by cortisol, but is inhibited by PDGF in the absence of cortisol. RU486 completely prevented aromatase induction by cortisol and PDGF. Induction by db-cAMP in the presence and absence of cortisol was significantly inhibited by RU486. Even lower activities were measured when RU486 was added to cells stimulated with PDGF and db-cAMP in the absence or presence of cortisol. Similar results were obtained after prolonged incubation. The inhibitory effects of RU486 are dose dependent, less than 1 microM completely blocking the effects of cortisol, whereas 10 microM are needed to block db-cAMP induction. RU486 does not affect cell number, cellular protein, viability or house-keeping enzymes such as lactate dehydrogenase (LDH), and therefore seems to act specifically. The time course of RU486 action on the db-cAMP induction of aromatase indicates that it acts via a newly synthetized mediator or target in stromal cells. These results suggest that all known inducers of aromatase in adipose tissue depend upon the action of signalling molecules (probably members of the nuclear receptor superfamily) which can be blocked by RU486. The inhibitory action of PDGF seems to be independent of steroid hormone action, as seems some basal activity induced by db-cAMP. In conclusion, this in vitro study suggests that RU486 might be a useful tool for the therapy of estrogen-dependent tumours through its inhibition of aromatase induction.

Adipose Tissue↗

PubMed1997

Magnetic resonance imaging in valvular heart disease.

Magnetic resonance techniques can be employed to depict valvular abnormalities but are especially helpful in quantifying regurgitant or stenotic lesions which cannot be quantitatively assessed by other noninvasive techniques. Gradient echo techniques and phase velocity mapping are the most important magnetic resonance pulse sequences employed for these purposes. Valvular regurgitation can be quantitated by measuring the area of signal void on conventional gradient-echo images, by calculating stroke volume differences from k-space segmented gradient echo images, by measuring the proximal convergence zone from velocity encoded images or by comparing stroke volumes of the ventricles from velocity measurements. In contrast to this variety of possibilities in regurgitant lesions, stenotic lesions can only be quantitated by using velocity mapping techniques. Magnetic resonance spectroscopy can be used to assess myocardial metabolism in chronic valvular lesions. However, this tool needs further development and more clinical data before its use can be recommended to assess the necessity and optimal timing of surgical intervention.

Aortic Valve Insufficiency↗

PubMed1997

Structure and structure formation of the 20S proteasome.

Eukaryotic 20S proteasomes are complex oligomeric proteins. The maturation process of the 14 different alpha- and beta-subunits has to occur in a highly coordinate manner. In addition beta-subunits are synthesized as proproteins and correct processing has to be guaranteed during complex maturation. The structure formation can be subdivided in different phases. The knowledge of the individual phases is summarized in this publication. As a first step the newly synthesized monomers have to adopt the correct tertiary structure, a process that might be supported in the case of the beta-subunits by the intramolecular chaperone activity postulated for the prosequences. Subsequently the alpha-subunits form ring-like structures thereby providing docking sites for the different beta-subunits. The result most likely is a double ring structure (13S precursor) representing half-proteasomes, which contain immature proproteins. Two 13S precursors associate to form the proteolytically inactive 16S assembly intermediate which still contains unprocessed beta-monomers. In addition the chaperone Hsc73 is present within these particles suggesting an essential role during the structure formation process. The processing of monomers with an N-terminal threonine occurs within the 16S particles and is achieved autocatalytically by two subsequent processing events finally leading to the mature, active 20S proteasome.

Amino Acid Sequence↗

PubMed1997

Construction and functional characterization of scFv(14E1)-ETA - a novel, highly potent antibody-toxin specific for the EGF receptor.

Epidermal growth factor (EGF) receptor-overexpression is characteristic of many human tumours of epithelial origin and has been correlated with unfavourable patient prognosis. Its involvement in the malignant process, its elevated expression in tumours and its accessibility on the tumour cell surface make the EGF receptor a potential target for directed tumour therapy. We have previously characterized a recombinant antibody - Pseudomonas exotoxin A fusion protein, scFv(225)-ETA, which displayes antitumoral activity towards EGF receptor-overexpressing tumour cells but is less potent in tumour cell killing than TGF-alpha-ETA, a recombinant toxin using the natural EGF receptor ligand transforming growth factor alpha (TGF-alpha) as a targeting domain. Here, we describe the construction and functional characterization in vitro of a novel single-chain antibody-toxin, scFv(14E1)-ETA, based on the independently isolated EGF receptor-specific monoclonal antibody 14E1. ScFv(14E1)-ETA binds to an EGF receptor epitope that is very similar or identical to that of scFv(225)-ETA with nine times higher affinity than the latter and displays more than tenfold higher cytotoxic activity on EGF receptor-overexpressing tumour cells. ScFv(14E1)-ETA cell killing activity was very similar to that of TGF-alpha-ETA on receptor-overexpressing cells but, in contrast to the latter, scFv(14E1)-ETA was much more selective and did not display significant cytotoxic activity on cells expressing moderate EGF receptor levels.

ADP Ribose Transferases↗

PubMed1997

Induction of mesangial interleukin-6 synthesis by apoptotic U937 cells and monocytes.

Infiltration of the glomerular mesangium by monocytes and macrophages is a central pathologic feature in various forms of glomerulonephritis. Dependent on the presence and activity of local survival factors, monocytes may undergo apoptosis. Therefore, we looked for the interaction between cultured human mesangial cells (HMC) and intact, necrotic or apoptotic monocytic cells with different stages of programmed cell death (U937 cells and blood-derived human monocytes) and the possible evoked secretory responses of HMC. Interleukin-6 (IL-6) synthesis of HMC after a two hour co-culture with late apoptotic U937 cells was significantly increased (505 +/- 55 pg/ml) as compared to intact U937 cells (349 +/- 27 pg/ml; HMC alone, 319 +/- 62 pg/ml), and was further elevated after 20 hours (815 +/- 108 pg/ml). U937 cells alone, after incubation in HMC-conditioned medium or after coincubation with HMC, did not produce any detectable IL-6. A high mesangial IL-6 synthesis in response to apoptotic U937 cells was dependent on the cellular contact between HMC and U937 and could not be mimicked by apoptotic U937 culture supernatants. Radiolabeling studies indicated that HMC bound (16.6 +/- 2.4%) and ingested (12.5 +/- 1.9%) apoptotic U937 cells to a much higher amount as compared to intact U937 (5.3 +/- 2.0% binding; 5.0 +/- 1.1% phagocytosis). Binding and ingestion of monocytic cells undergoing apoptosis was confirmed by morphologic studies using electron microscopy. Incubation of HMC with a blocker of the CD36/ vitronectin receptor (VnR) dependent recognition mechanism of phagocytes for apoptotic leukocytes (RGDS peptide) did not alter binding, phagocytosis or IL-6 synthesis of HMC in response to apoptotic U937. Phospho-L-serine as an antagonist of the phosphatidylserine (PS) mediated recognition pathway for apoptotic cell disposal was able to reduce binding and IL-6 production by HMC but not phagocytosis. Thus, binding of apoptotic monocytic cells by HMC rather than ingestion may be the prerequisite for a stimulated secretory response. To elucidate whether binding and phagocytosis of particles in general might stimulate HMC to produce IL-6, we looked for mesangial IL-6 production after binding and ingestion of opsonized zymosan particles. In this case, IL-6 synthesis was markedly down-regulated. Furthermore, HMC proliferated after zymosan treatment, whereas after apoptotic cell uptake the mesangial cell number remained constant. In conclusion, apoptotic monocytic cells provoked an enhanced mesangial IL-6 synthesis by a PS-dependent recognition mechanism. This secretory response may have secondary implications for humoral or cellular processes within the mesangium.

Apoptosis↗

PubMed1997

Underestimation of inversion (16) in acute myeloid leukaemia using standard cytogenetics as compared with polymerase chain reaction: results of a prospective investigation.

In order to determine whether the polymerase chain reaction (PCR) is more suitable for the detection of inversion (16) as compared with standard cytogenetics, we prospectively investigated a total of 132 cases of de novo acute myeloid leukaemia (AML) (n = 121) and secondary AML after myelodysplastic syndromes (MDS) (n = 11) using a sensitive and nested PCR procedure to detect the fusion transcripts CBFbeta-MYH11. All patients were recruited within 10 months in an ongoing multicentre AML-trial. In addition, several cases from a retrospective molecular analysis were included. The data were compared with standard cytogenetics performed in a central laboratory. Of the 132 prospective AML cases, five patients (3.7%) harboured inv(16) upon conventional cytogenetics. In all cases fusion transcripts CBFbeta-MYH11 were detected using PCR. In addition in two patients fusion transcripts were detected, although cytogenetics revealed a normal karyotype. In the group of patients analysed retrospectively, four patients harboured fusion transcripts specific for CBFbeta-MYH11; cytogenetics were normal in one case, and could not be evaluated in two cases. These data show that PCR may be a better means to detect inv(16) in AML. Since inv(16) may have prognostic impact in AML, detection of this aberration seems important in the clinical management of AML patients.

Acute Disease↗

PubMed1997

[Ultrafast contrast-enhanced 3D MR angiography of the aorta and renal arteries in apnea].

PURPOSE: To determine the value of ultrafast, gadolinium-enhanced, three-dimensional breathhold magnetic resonance angiography (MRA) in the assessment of the aorta and renal arteries in comparison to conventional arteriography (CA). PATIENTS AND METHODS: 49 patients (31 m, 18 f) were evaluated with both CA and 3D MRA. The 3D MRA data set consisted of 44 continuous sections, acquired in apnoea (23-28 s) using the following parameters: TR/TE 3.9/1.5 ms, flip angle 40 degrees, 3/4 k-space acquisition. 0.3 mmol/kg BW gadolinium-DTPA were administered intravenously in a bolus, using an automated injector. A test bolus method was used for timing of the bolus and beginning of the data acquisition. Intraarterial CA was used as the gold standard in 47 patients; in two patients the intraoperative findings were employed as the standard of reference. CA and MRA were interpreted separately by two different radiologists, who were blinded to the results of the other examiner. RESULTS: All 11 accessory renal arteries were visualised on MRA. MRA-based assessment of renal artery stenosis was identical with CA in 31 of 41 (75%) stenoses, Sensitivity and specificity values for assessment of renal arterial disease were 84.4% and 96.1%, for haemodynamically significant lesions they amounted to 90% and 98.9%, respectively. CONCLUSION: The presented ultrafast contrast-enhanced 3D MRA technique allows for the reliable assessment of aortic and renal arterial morphology and pathology.

Adult↗