What works. Managed care friendly MSO WAN improves physician access, billing accuracy.
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Ambulatory Care Information Systems↗
Biomedical subjects
M Schmidt
Publications and source records attributed to M Schmidt.
Gi- and protein kinase C-mediated heterologous potentiation of phospholipase C signaling by G protein-coupled receptors.
We recently reported that activation of the highly efficient phospholipase C (PLC) stimulatory m3 muscarinic acetylcholine receptor (mAChR) can induce a long-lasting Gi-mediated heterologous potentiation of PLC stimulation in human embryonic kidney (HEK) 293 cells, which was accompanied by an increased cellular level of the PLC substrate phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P2]. Here, we examined whether such a potentiated PLC response is also induced by the rather poorly PLC stimulatory m2 mAChR and the endogenously expressed purinergic and lysophosphatidic acid receptors. Pretreatment of m2 mAChR-expressing HEK 293 cells for 2 min with carbachol, followed by agonist washout and measurement of PLC activity >/=40 min later, caused a long-lasting (up to approximately 90 min) heterologous potentiation of receptor- and G protein-mediated PLC stimulation. A similar heterologous potentiation of receptor-mediated PLC stimulation was induced by short term activation of lysophosphatidic acid and purinergic receptors. Either of the three receptor agonists increased the cellular level of PtdIns(4,5)P2 by approximately 50%. The mAChR-induced PLC potentiation was fully prevented by either pertussis toxin or the protein kinase C (PKC) inhibitors staurosporine and Gö 6976, which did not affect acute PLC stimulation. On the other hand, the rise in PtdIns(4,5)P2 was prevented only by combined treatment of HEK 293 cells with pertussis toxin and PKC inhibitors. In conclusion, we demonstrated that activation of poorly PLC stimulatory receptors can also induce a long-lasting Gi-mediated heterologous potentiation of PLC signaling in HEK 293 cells and that this novel PLC regulatory process is under the control of PKC.
Adenosine Triphosphate↗
Amiodarone-induced severe hepatitis mediated by immunological mechanisms.
A 64-year-old man developed a fulminant hepatitis 4 days after initiation of amiodarone treatment and a total dose of 7.1 g. The direct Coombs test was positive and became negative again soon after stopping treatment. Immediately after stopping treatment the extremely increased parameters of hepatic failure returned to normal again. A rechallenge with 200 mg of amiodarone was accompanied by a positive Coombs test which again became negative after several days. We conclude that the occurrence of an acute hepatitis soon after initiation of amiodarone treatment is mediated by immunological mechanisms. There should be high vigilance with respect to this rare life-threatening adverse drug reaction.
Amiodarone↗
[Appendicitis in pregnancy].
The incidence of appendicitis is about 1:1000-1:1500 pregnancies. Therefore, it seems to be in pregnancy as frequent as in the general population. The common signs and symptoms of appendicitis are in pregnancy less reliable than in nonpregnant women. An important role to diagnose appendicitis in suspicious cases has the ultrasonography, first of all the "graded compression ultrasound". Appendicitis increases the rate of spontaneous abortions, preterm delivery, small for gestation babies, and neonatal mortality in the first 7 days of life. After appendectomy the rate for preterm deliveries is increased for seven days. After the 7th postoperative day the pregnancy usually continuous to term. There is no increase of malformations because of appendectomy. At the end of pregnancy appendicitis is frequently complicated by phlegmoneous and perforated forms of illness with and without peritonitis. Before 20th w.o.p. laparoscopy is a recommendable method to diagnose and treat appendicitis. After 20th week of pregnancy laparotomy should be preferred. Cesarean section is not recognized part of treatment for appendectomy and only to be performed for obstetric reasons. Tocolysis should be prevented because of risk of pulmonary injury.
Appendectomy↗
[Laparoscopic appendectomy as standard procedure. Technique and outcome in 409 patients].
UNLABELLED: In the framework of a prospective clinical trial we wanted to show that minimal access surgery as a standard treatment of acute appendicitis leads to good results. PATIENTS AND METHOD: From January 1993 to December 1996 409 patients had a laparoscopic appendectomy in the Surgical Department of Krankenhaus Zehlendorf, Berlin. We treated 252 female (62%) and 157 male (38%). The mean age was 31.5 years (min. 8 years, max. 81 years) The conversion rate was 8% (33 patients). Reasons for conversion were perforation or difficult anatomical conditions. In 189 patients we found additional diagnosis as adhesions, gynecological diseases or chronic inflammatory bowel diseases. RESULTS: The clinical diagnosis sensitivity histological correlated was 83%. The mean operating time was 46 minutes (min. 10, max. 120 minutes). The basis of appendix was routinely carried by loop of catgut in 342 cases. In 23 cases was used the Endo-GIA. Severe postoperative complications were seen in 2%. In 1.3% planned second-look laparoscopy with drainage was performed. The patients stayed in hospital for 5 days in median (min. 1 day, max. 21 days). The rate of wound infections was decreased specially in fat patients.
Acute Disease↗
[Dr Jekyll and Mr. Hyde in the nursing home].
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Aged↗
Regulation of human monocyte apoptosis by the CD14 molecule.
Bacterial products such as LPS have been shown to activate monocytes and to increase CD14 expression, while anti-inflammatory cytokines, i.e., IL-4, down-regulate CD14. Furthermore, activation of monocytes increases survival, whereas deactivation evokes apoptosis (programmed cell death, PCD). This correlation among activation, CD14 expression, and the lifespan of the cells prompted us to investigate the role of CD14 in monocyte apoptosis. The effects of LPS and IL-4 on the expression of CD14, indicated by binding of Leu M3 Ab, and PCD of monocytes were studied simultaneously and in a kinetic fashion by multiparameter flow cytometry. Monocyte PCD was determined by binding of FITC-conjugated annexin V, which indicates apoptotic cell death in early stages, and was confirmed using well-established detection methods, i.e., DNA electrophoresis, electron microscopy, or colorimetric DNA staining. The present study shows that the LPS-induced increase in CD14 expression rescued monocytes from apoptosis, whereas IL-4 treatment first down-regulated CD14 expression and consecutively evoked apoptosis. CD14-/annexin V- monocytes were not apoptotic as confirmed by DNA electrophoresis, whereas CD14-/ annexin V+ monocytes showed clear apoptotic features. Kinetic studies ruled out that monocytes first bound annexin V and later lost the CD14 Ag. Other molecules, such as HLA-A, -B, and -C Ags, were not down-regulated during apoptosis. Enzymatic removal of membrane-bound CD14 by phosphatidylinositol-specific phospholipase C evoked PCD similarly to IL-4. These results suggest that regulation of CD14 receptor expression is an early effector mechanism mediating life or death of monocytes. Down-regulation or removal of the receptor triggers apoptosis, whereas up-regulation promotes survival.
Annexin A5↗
Targeted therapy of schwannoma cells in immunocompetent rats with an erbB2-specific antibody-toxin.
Over-expression of the erbB2-receptor tyrosine kinase is frequently observed in many human tumors of epithelial origin. Due to its causal involvement in malignant transformation and its presence on the tumor cell surface erbB2 is an attractive target for directed tumor therapy. We earlier described the potent anti-tumoral activity of the recombinant single-chain antibody toxin scFv(FRP5)-ETA in vitro and in nude mouse tumor models in vivo. This molecule consists of the variable domains of the heavy and light chains of an erbB2-specific antibody genetically fused to a truncated Pseudomonas exotoxin A. Here we have investigated the in vivo effects of this immunotoxin on erbB2 expressing NV2Cd schwannoma cells growing as s.c. tumors in syngeneic BDIX rats. Established tumors were treated either locally by intra-tumoral injection of scFv(FRP5)-ETA or systemically by injection into the tail vein. Both routes of application resulted in pronounced inhibition of tumor growth with local treatment being more effective. Treatment with 25 micrograms/day of scFv(FRP5)-ETA for 10 days suppressed tumor growth almost completely. Antibodies directed mainly against the toxin domain of the fusion protein developed in all animals treated.
ADP Ribose Transferases↗
Characteristics of protein-kinase-C- and ADP-ribosylation-factor-stimulated phospholipase D activities in human embryonic kidney cells.
Phospholipase D (PLD) activity in human embryonic kidney (HEK) cells is stimulated by phorbol-ester-activated protein kinase C (PKC) and by membrane receptors, the latter apparently acting via the GTP-binding proteins, ADP-ribosylation factor (ARF) and Rho. In the present study, performed in cell-free preparations, we have characterized and compared the regulation of HEK cell PLD activity by the stable GTP analogue, guanosine 5'-O-[gamma-thio]triphosphate (GTP[S]), and the phorbol ester, phorbol 12-myristate 13-acetate (PMA). In digitonin-permeabilized HEK cells, prelabeled with [3H]oleic acid, GTP[S] and PMA caused an approximately threefold concentration-dependent increase in the formation of [3H]phosphatidylethanol, measured in the presence of ethanol. Neomycin, which is known to complex with the PLD cofactor, phosphatidylinositol 4,5-bisphosphate, decreased basal and GTP[S]- or PMA-stimulated PLD activities with similar sensitivity. GDP and its analogue, guanosine 5'-O-[beta-thio]diphosphate, inhibited the stimulatory effect of GTP[S], whereas the PMA response was prevented by the nonselective PKC inhibitor, staurosporine, but not vice versa. PLD stimulation by GTP[S], but not by PMA, was markedly reduced upon cytosol depletion and reconstituted by purified recombinant ARF1. In HEK cell membranes, addition of purified recombinant ARNO, a guanine-nucleotide-exchange factor for ARF1. potentiated the GTP[S]-stimulated PLD activity. PLD stimulation by PMA in HEK cell membranes required MgATP and was largely prevented by the selective PKC inhibitors Goe 6976 and bisindolylmaleimide I. Immunoblot analysis demonstrated that both conventional PKC (alpha, beta, gamma) and atypical PKC isozymes (zeta, tau) were present in HEK cell membranes. The results indicate that phorbol ester stimulation of PLD activity in HEK cells apparently occurs by a phosphorylation-dependent mechanism involving membrane-associated PKC isozymes but not ARF proteins, the major targets of GTP[S]' action.
ADP-Ribosylation Factor 1↗
Continuous neurogenesis in the olfactory brain of adult shore crabs, Carcinus maenas.
To scrutinize the common belief that the number of neurons in the CNS of adult decapod crustaceans stays constant, in spite of their dramatic postlarval increase in size, I counted olfactory projection neurons (OPNs) in the brains of differently-sized postlarval shore crabs, Carcinus maenas, and performed in vivo labeling of proliferating cells with 5-bromo-2'-deoxyuridine (BrdU) on brains of adults. The number of OPNs increases continuously throughout the postlarval life of shore crabs and approximately doubles from the very young to the oldest animals. Brain sections from adult crabs labeled with BrdU revealed ongoing proliferation of cells in the lateral soma cluster, which consists of OPN cell bodies, and in the cluster of somata of hemiellipsoid body local interneurons, which are the targets of the OPNs. Post-injection survival times from 5.5 to 120 h revealed a small but relatively constant number of labeled nuclei with neuronal morphology in both soma clusters of all specimens (31.3 +/- 9.5 S.D. nuclei per lateral cluster, n = 29; 20.1 +/- 4.5 S.D. nuclei per hemiellipsoid body cluster, n = 10). The labeled nuclei were located in a distinct proliferative zone in each cluster. There were significantly more labeled nuclei in both soma clusters after a prolonged post-injection survival time of 1 month (71.3 +/- 7.8 S.D. nuclei per lateral cluster, n = 4; 38.2 +/- 7.1 nuclei per hemiellipsoid body cluster, n = 6). In both soma clusters the labeled nuclei formed a compact group that was dislocated from the proliferation zone towards the outer edge of the cluster. In the proliferation zone of the lateral cluster histological stainings revealed cell bodies of typical neuronal shape that are slightly smaller and more intensely stained than the surrounding OPN somata. Some of these cell bodies were captured in various stages of mitosis. Collectively, these data indicate that continuous neurogenesis occurs in the central olfactory pathway of the brain of shore crabs throughout their entire adult life. This unexpected structural plasticity may enable long-lived decapod crustaceans to adapt to ever-changing olfactory environments.
Age Factors↗
[Rehabilitation in brain injuries--contribution of computer-assisted training].
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Brain Injuries↗
The complete cDNA sequence and expression of the first major allergenic protein of Malassezia furfur, Mal f 1.
For the first time the complete cDNA encoding a major allergen and novel protein of the yeast Malassezia furfur, Mal f 1, has been sequenced and expressed. The amino acid sequences of nine tryptic peptides of the protein were determined. Oligonucleotides were designed from these amino acid sequences. The cDNA sequence was obtained by hybridizing these primers to mRNA and enhancement by reverse-transcriptase PCR techniques. The cDNA is 1176 bp in length. It shows an open reading frame of 1050 bp coding for a protein of 38178 Da and a deduced amino acid sequence containing 350 residues. The hydropathy plot and the tryptic digest indicate that the first 22 amino acids represent a leader sequence determining a mature protein of 35 988 Da. The complete encoding cDNA was expressed as a maltose-binding protein fusion protein in Escherichia coli. The recombinant fusion protein reacted with our specific monoclonal antibody and with IgE from patients with atopic dermatitis.
Allergens↗
Maturation of mammalian 20 S proteasome: purification and characterization of 13 S and 16 S proteasome precursor complexes.
The maturation of the eukaryotic 20 S proteasome complex occurs via 13 S and 16 S precursor complexes in a multistep assembly pathway. These precursor complexes contain alpha-subunits as well as unprocessed beta-subunit proproteins. We have purified and characterized the different proteasome assembly intermediates and analysed their ability to support beta-subunit proprotein processing in vitro. Our data show that 13 S and 16 S proteasome precursor complexes differ not only in size but also in their protein content and behaviour during hydrophobic chromatography. By establishing conditions which allowed us to analyse beta-prosubunit maturation in vitro we demonstrate that the processing of the homologous proproteins of the beta-subunits LMP2 and delta essentially takes place in 16 S precursor complexes. No proprotein processing activity was observed in 13 S precursor complexes. Furthermore, proprotein processing in vitro can be inhibited with a proteasome specific inhibitor, but with different efficiency for LMP2 and delta. A peptide, which represents the sequence of the proprotein processing site HGTT, exhibited no inhibitory effect on the processing of either subunit. These data provide further evidence that proprotein processing occurs via an autocatalytic mechanism. Our experiments also demonstrate that the chaperone protein hsc73 is associated with 16 S but not with 13 S precursor complexes. In support of the specificity of this interaction incubation with ATP leads to the dissociation of hsc73 from 16 S complexes and to the formation of high molecular weight aggregates. Prosubunit processing in isolated 16 S complexes does not, however, result in the formation of proteolytically active 20 S proteasomes which may be due to the fact that not all beta-subunits can be efficiently processed in vitro. In contrast to previous assumptions subunit processing and formation of proteolytic activity do not coincide and final 20 S complex assembly seems to represent in part a separate event which requires additional factors or proteins which are not present or active in the purified 16 S precursor complexes.
B-Lymphocytes↗
Long terminal repeat U3 length polymorphism of human foamy virus.
Size determination of the long terminal repeat (LTR) of an early (1985) and a more recent (1993) passage of wild-type human foamy virus (HFV) revealed that the virus has undergone substantial deletions in the U3 region upon replication in tissue culture. Two LTR deletion variants (HSRV1 and 2) have been characterized in the past and used to construct molecular clones which are replication competent in cell culture. We now report the molecular cloning, sequencing, and biological characterization of an HFV genome with full-length LTR (pHFV2). Sequence analysis revealed that the deletions in HSRV1 and 2 are nonrandom and probably occurred by misalignment during reverse transcription. The comparative analysis of HFV2 and the variant with the largest U3 deletion, HSRV2, revealed a differential ability to replicate in human cell cultures. While HSRV2 replicated faster in diploid human fibroblasts, cells which have been used extensively for amplification of HFV in the past, replication of HFV2 was faster in a lymphoblastoid cell line. Reporter gene assays indicated that the cell-type specific ability of the LTRs to respond to the viral transcriptional transactivator may be a likely, reason for the different growth properties of both viruses and for the occurrence of the HFV U3 deletions. In foamy virus-infected chimpanzees only the full-length type of LTR was observed; however, the HSRV1 deletion variant was detected as the dominating virus in an accidentally HFV-infected human.
Animals↗
Distribution of centrifugal neurons targeting the soma clusters of the olfactory midbrain among decapod crustaceans.
To determine the distribution of two systems of centrifugal neurons innervating the soma clusters of the olfactory midbrain across decapod crustaceans, brains of the following nine species comprising most infraorders were immunostained with antibodies against dopamine and the neuropeptides substance P and FMRFamide: Macrobrachium rosenbergii, Homarus americanus, Cherax destructor, Orconectes limosus, Procambarus clarkii, Astacus leptodactylus, Carcinus maenas, Eriocheir sinensis and Pagurus bernhardus. One system consisting of several neurons with dopamine-like immunoreactivity that originate in the eyestalk ganglia was present in the four crayfish but not in any other species. These neurons project mainly into the lateral soma clusters (cluster 10) comprising the somata of ascending olfactory projection neurons and innervate very sparsely the medial soma clusters (clusters 9 and 11) containing the somata of local interneurons. In the innervation pattern of the lateral cluster, the dopamine-immunoreactive neurons showed large species-specific differences. The other system comprises a pair of giant neurons with substance P-like immunoreactivity. These neurons have somata in the median protocerebrum of the central brain and major projections into the lateral clusters and the core of the olfactory lobes, the neuropils that are the first synaptic relay in the central olfactory pathway of decapods; minor arborizations are present in the medial clusters. The system of substance P-immunoreactive giant neurons was present and of great morphological similarity in all studied species. Only in one species, the shrimp Macrobrachium rosenbergii, evidence for co-localization of FMRFamide-like with substance P-like immunoreactivity in these neurons was obtained. These and previously collected data indicate that the centrifugal neurons with dopamine-like immunoreactivity may be associated with the presence of an accessory lobe, a second-order neuropil that receives input from the olfactory lobe and only occurs in spiny lobsters, clawed lobsters and crayfish. The pair of centrifugal giant neurons with substance P-like immunoreactivity, on the other hand, appears to be a constitutive component of the decapod crustacean brain that most likely is functionally associated with the olfactory lobe. Both systems apparently exert modulatory functions on olfactory information processing by preferentially targeting the somata of the projection neurons. Thus, in the olfactory projection neurons, the somata seem to be more directly involved in information processing than in most other neurons of the arthropod CNS.
Animals↗
Intra-tumoral application of a heregulin-exotoxin-a fusion protein causes rapid tumor regression without adverse systemic or local effects.
Tumor toxins are recombinant, bifunctional proteins which comprise a tumor-cell-specific recognition domain and an enzymatic toxin domain. We have evaluated the in vivo effects of a tumor toxin that specifically recognizes the erbB-3 and erbB-4 receptors (HRG beta 1-ETA). High doses of HRG beta 1-ETA administered systemically (intracardially or intraperitoneally) caused acute liver necrosis and were lethal. The same dose of tumor toxins applied subcutaneously had no detectable histopathological effects. The anti-tumor activity of HRG beta 1-ETA was tested in nude mice with xenografts of a human breast tumor, MAXF1162. The MAXF1162 tumor grew rapidly upon s.c. implantation. Intra-tumoral application of HRG beta 1-ETA (7 times 5 micrograms over a period of 21 days) induced complete regression of tumors. At the time the treatment was terminated, no tumor cells were detectable microscopically. Evaluation of the liver of treated animals revealed no significant toxicity in the effective dose range. These experiments indicate that tumor toxins can become valuable for local tumor treatment and for reduction of tumor burden.
Animals↗
Muscarinic receptor-stimulated cytosol-membrane translocation of RhoA.
Receptor-mediated phospholipase D activation in human embryonic kidney (HEK) cells stably expressing the m3 muscarinic acetylcholine receptor (mAChR) apparently involves the small G protein RhoA. Here, activation of RhoA was examined by measuring cytosol-membrane translocation, which is a sign of RhoA activation. RhoA translocation was induced by guanosine 5'-O-(3-thio)triphosphate in digitonin-permeabilized HEK cells, and in intact cells by the agonist-activated mAChR and by direct activation of heterotrimeric G proteins. RhoA translocation was also induced by the phosphotyrosine phosphatase inhibitor pervanadate, while the tyrosine kinase inhibitors tyrphostin 23 and genistein inhibited the mAChR-induced RhoA translocation. These data suggest that translocation and thus activation of RhoA by the G protein-coupled m3 mAChR in HEK cells apparently involves a tyrosine kinase-dependent reaction.
Atropine↗
Distribution of presumptive chemosensory afferents with FMRFamide- or substance P-like immunoreactivity in decapod crustaceans.
In five species of decapod crustaceans--Cherax destructor (crayfish), Carcinus maenas (crab), Homarus americanus (clawed lobster), Eriocheir sinensis (crab), Macrobrachium rosenbergii (shrimp)--immunocytochemical stainings revealed the presence of sensory afferents with FMRFamide-like immunoreactivity in the central nervous system. These afferents were extremely thin, very numerous, and innervated all sensory neuropils except the optic and olfactory lobes. In their target neuropils they gave rise to condensed net- or ball-like terminal structures. Only in Homarus americanus but not in any other studied species immunocytochemistry revealed a separate, non-overlapping class of sensory afferents with substance P-like immunoreactivity. Also the afferents with substance P-like immunoreactivity were very thin and numerous, innervated all sensory neuropils except optic and olfactory lobes, and gave rise to condensed terminal structures. From their morphological characteristics it can be concluded that likely both classes of afferents are chemosensory. The substance P-like immunoreactivity suggests a link with the nociceptor afferents of vertebrates, with which both classes of afferents share several other morphological features.
Animals↗