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G Thiel

Publications and source records attributed to G Thiel.

At least 109 records · Page 6Linked to original sources
PubMed1995

Parallel genome analysis by one- and two-dimensional DNA fingerprinting in human gliomas.

The detection of DNA variation in cancers is an important step in elucidating the mechanism of tumorigenesis. Using the strategy of multipoint genome analysis we detected many differences between glioma-derived and constitutional DNA by customary DNA fingerprinting with simple repetitive oligonucleotide probes. Amplification of the epidermal growth factor receptor (EGFR) gene has been found to be easily detectable as new or highly intensified bands in one-dimensional (1-D) DNA fingerprints of glioblastoma DNA generated with probes (GTG)5 or (GT)8. However, in most low-grade astrocytomas, 1-D DNA fingerprinting has failed to reveal any genomic abnormalities. In these cases a two-dimensional (2-D) technique was successfully employed that is based on size separation in neutral gels followed by sequence-dependent separation in denaturing gradient gels and hybridization with several mini- and microsatellite core probes. The hundreds of spots visualized with this technique were used to detect subtle changes probably occurring as the initial steps of tumorigenesis in human gliomas. On average, five of the approximately 580 spots generated by probes CAC and 33.6 were found to be altered in tumor DNA; 80% of the alterations were spot losses, the rest being spot gains or amplifications. Computer-based image analysis using an external lambda marker provided a stringent way to compare spot patterns generated by 2-D DNA fingerprinting. In comparisons performed between typing patterns generated on the same gel, 99% of truly identical spots were confirmed by the software. In intergel comparisons 84% of identical spots were matched on the basis of the marker information alone.

Base Sequence↗
PubMed1995

Involvement of chromosome 22 in ependymomas.

We have karyotyped a total of twelve ependymomas using GTG-banding including seven for which preliminary results have already been published. One case showing hyperdiploid main line with two marker chromosomes was further analyzed by nonisotopic chromosome in situ suppression hybridization. It was shown that the marker chromosomes consisted of 1q, 14q and 1q, and 22q. The possible role of chromosome 22 in ependymomas and the usefulness of fluorescence in situ hybridization for cytogenetic analysis in tumor investigation are discussed.

Adolescent↗
PubMed1995

Karyomegalic interstitial nephritis: further support for a distinct entity and evidence for a genetic defect.

Karyomegalic interstitial nephritis was first described in 1979 by Mihatsch, who was reporting three such cases. We report here four additional cases as well as two family investigations. Our findings support the association of karyomegaly and interstitial nephritis as a distinct entity. Typical clinical features are asymptomatic progressive renal failure in the third decade of life and recurrent infections, mostly of the upper respiratory tract. Histologic alterations consist of markedly enlarged and hyperchromic nuclei in many tubular epithelial cells throughout the nephron accompanied by interstitial fibrosis in the surrounding atrophic tubules. Karyomegaly is not limited to the kidneys. In one case, autopsy revealed karyomegaly in epithelial and mesenchymal cells of many other organs. However, no association of karyomegaly with further histologic damage is evident except in the kidneys. Because of the familial clustering, karyomegalic interstitial nephritis seems to be an inherited disease. Examination of the nuclear proliferation-associated structures proliferating cell nuclear antigen/cyclin, Ki 67, and p53 suggests an inhibition of mitosis in karyomegalic cells. The finding of the same HLA haplotype, A9/B35, in four of six HLA-typed cases suggests the possibility of a genetic defect on chromosome 6, which is inherited and linked to the HLA locus.

Adult↗
PubMed1995

The value of different resistance parameters in distinguishing biopsy-proved dysfunction of renal allografts.

The data concerning the value of duplex sonography in diagnosing parenchymatous renal allograft dysfunction are controversial. Most early studies did not take into consideration the many factors influencing resistance parameters. We therefore performed a prospective, biopsy-controlled study with exclusion of all known sources of error regarding resistance parameters. Furthermore we investigated the value of a new resistance parameter, the systolic deceleration percentage. Forty-seven duplex sonographic studies were performed on 43 patients (30 male, 13 female, median age 47 years, range 7-70). Fourteen studies were done on normally functioning grafts (control group) an average of 33 days after transplantation. Thirty-three studies were performed on dysfunctional grafts immediately prior to biopsy. Grafts which had been transplanted more than a year previously or with vascular findings or any other clinical or sonographic pathology probably explaining function deterioration were excluded. In all patients, the resistive index (RI), pulsatility index (PI) and systolic deceleration percentage (DP) were calculated in the main renal artery and in the interlobar artery. Of the 33 grafts with dysfunction, nine had vascular rejection (VR), 11 interstitial rejection (IR), 11 cyclosporin A toxicity (CAT) and two other histologies (OR). The mean RI in normal grafts (NO) was 0.71 +/- 0.06 in the main artery and 0.68 +/- 0.06 in the interlobar artery, in VR 0.86 +/- 0.12 and 0.80 +/- 0.18, in IR 0.72 +/- 0.05 and 0.70 +/- 0.07, in CAT 0.67 +/- 0.06 and 0.65 +/- 0.07 and in OR 0.64 +/- 0.07 and 0.60 +/- 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

[Follow-up care of living kidney donors].

The follow-up of living kidney donors demands medical as well as psychological competence. In the postoperative period, attention focuses on pain management, early detection of wound complications and the prophylaxis of thromboembolism. Regular visits of the donor who may easily feel neglected should be as much part of the transplant team's post-operative routine as visits of the recipient. The later phase of recovery emphasizes strengthening abdominal wall and lumbar muscles as well as the gradual increase of physical activity. Long-term follow-up focuses on the early detection of arterial hypertension and proteinuria. Antihypertensive therapy in nephrectomized donors should include an ACE inhibitor or an angiotensin-II antagonist. In Switzerland, the long-term course after living donation is prospectively monitored by the Swiss Registry for Living Donors founded in 1993. The registry is responsible for the regular timing of follow-up examinations and assures transparency of the origin of the kidneys used for living donation in Switzerland. The registry heavily relies on the collaboration of the donor's family physicians.

Female↗
PubMed1995

ET-1 excretion is urine flow-dependent in kidney donors and transplant recipients.

Urinary endothelin-1 excretion (uET-1/min) has been reported to be elevated under cyclosporin A (CsA) therapy in kidney transplant recipients (KR). The possible flow-dependence of uET-1/min was not considered. Therefore, we studied the effect of water diuresis on uET-1/min in KR 1 year after transplantation and used kidney donors (KD) as controls. Urinary ET-1/min and urine flow (uFlow) were measured in 25 KR and in 21 KD before and 27 KD 1 year after surgery (KD-Nx) during water diuresis induced by oral hydration in a 12 h overnight collection. uET-1/min was correlated with uFlow. uET-1/min in 12-h overnight collection was similar in KD, KD-Nx, and KR (127 +/- 55, 110 +/- 42, and 122 +/- 53 pg/min respectively). Urine flow did not differ significantly among the three groups (range 0.6-3.7 ml/min). uET-1/min correlated significantly with urine flow in KD, KD-Nx, and KR (r = 0.59, r = 0.42, and r = 0.53, p < 0.03, respectively). The slope of the three regression lines was not different. There was no correlation of uET-1/min with CsA trough level or dose. uET-1/min is urine flow-dependent during water diuresis. Because NaCl diuresis has been reported to have no influence on uET-1/min, we hypothesize that uET-1/min is linked to the state of diuresis or antidiuresis in the distal nephron. CsA therapy does not influence uET-1/min in a 12-h urine collection.

Adult↗
PubMed1994

Differential regulation of chromogranin B and synapsin I gene promoter activity by cAMP and cAMP-dependent protein kinase.

cAMP has neutrotrophic effects in the nervous system. We have investigated whether there is a correlation between cAMP-induced neurite outgrowth and induction of chromogranin B and synapsin I gene expression. These genes encode marker proteins of distinct populations of vesicles in neurons, neuroendocrine and endocrine cells, and in addition, they contain a cAMP response element (CRE) in their upstream regions, making it likely that cAMP-induced neuronal differentiation might be accompanied by increased transcription of these genes. We increased intracellular cAMP levels in neuronal and neuroendocrine cells and analyzed the levels of chromogranin B and synapsin I mRNA. Our data revealed that, while chromogranin B mRNA was in fact induced following cAMP stimulation, synapsin I mRNA was not affected. To analyze the cis-acting sequences, we constructed hybrid genes containing the upstream region of the mouse chromogranin B gene fused to a reporter gene. Similar plasmids containing the synapsin I or the glucagon promoter were constructed. Transfections of neuronal and endocrine cells, together with deletion mutagenesis, revealed that the CRE of the chromogranin B gene mediated the effect of cAMP upon transcription. This effect was mimicked by overexpression of the catalytic subunit of the cAMP-dependent protein kinase. In addition, overexpression of the negative-acting CRE-binding protein CREB-2 revealed that the chromogranin B CRE functions as a bifunctional genetic regulatory element in that it mediates basal as well as cAMP-stimulated transcription. Synapsin I gene expression, however, was not induced by either elevated intracellular cAMP concentration or by overexpression of protein kinase A, although a similar pattern of proteins, including CREB, bound to the synapsin I and chromogranin B CRE in vitro. Thus while the CRE element in the chromogranin B gene promoter is responsive to cAMP, the same element, when present in the synapsin I promoter, does not confer cAMP inducibility.

1-Methyl-3-isobutylxanthine↗
PubMed1994

[Early diagnosis of cytomegalovirus infection and disease in patients following kidney transplantation].

For early diagnosis of cytomegalovirus (CMV) infection after renal transplantation, 18 patients were monitored within the first 3 months. Blood leukocytes were assayed weekly for the presence of the CMV matrix protein p65 (antigenemia assay) and CMV DNA by the polymerase chain reaction (PCR). In 12 out of 18 patients, 70 (37.8%) of 185 blood samples were positive by antigenemia assay or by PCR. 49 and 115 samples concurrently were positive and negative by both tests. 8 blood samples were positive only by the antigenemia assay and 13 only by PCR. Therefore, the relative sensitivity of PCR and of antigenemia assay was 88.6% and 81.4% respectively. In 9 of 10 patients who were pre-transplant CMV seropositive and in 4 of 7 patients who were pre-transplant CMV seronegative and received a graft from a seropositive donor, CMV infection was detected by positive antigenemia and/or PCR. Four of these patients developed CMV disease. In all these patients, antigenemia assay and PCR were positive 7 to 16 days prior to onset of clinical symptoms. Antigenemia and PCR are rapid and sensitive methods for the detection of CMV infection 1 to 2 weeks prior to disease. In addition, the semi-quantitative assay of antigenemia enables monitoring of the efficacy of antiviral therapy.

Cytomegalovirus↗
PubMed1994

Regulation of synapsin I gene expression by the zinc finger transcription factor zif268/egr-1.

zif268/egr-1 is an immediate early response gene that is involved in regulation of growth and differentiation. Its mRNA encodes a sequence-specific transcriptional activator containing three zinc fingers that act as the DNA-binding domain. Although zif268/egr-1 is expressed in the nervous system during neuronal excitation, no target gene has yet been identified. Here we report that the zif268/egr-1 protein bound in vitro to two sites in the proximal regulatory region of the human synapsin I gene. The zif268/egr-1 protein was also shown to stimulate transcription from this control region in transactivation assays. Additionally, the presence of a putative neural-restrictive silencer element next to one of the zif268/egr-1-binding sites interfered with transactivation in a tissue-independent manner. An analysis of the temporal expression pattern of zif268/egr-1 and synapsin I during neuronal differentiation of P19 embryonal carcinoma cells revealed that zif268/egr-1 mRNA was induced on day 5 and synapsin I mRNA on day 8 after retinoic acid treatment. From this data we conclude that the synapsin I gene is a target of the zif268 transcription factor; however, intermediate factors may also be involved in the activation.

Base Sequence↗
PubMed1994

Weight-independent dosing of cyclosporine--an alternative to the "mg/kg" doctrine.

Cyclosporine is usually prescribed as "mg CsA per kg body weight", and blood levels are used for guiding CsA therapy. The present study evaluated whether it is sensible to dose in "mg/kg" if one wishes to obtain specific CsA blood levels. In a retrospective analysis, 1071 consecutive CsA whole-blood trough levels from 164 renal transplant patients, measured by monoclonal parent RIA, were correlated with the respective oral CsA doses and several demographic parameters, including gender, age, weight, height, and time after transplantation. From this, we derived a concept of "weight-independent CsA dosing" which was prospectively tested in three series of patients during the first days after renal transplantation: 58 patients received 2x 100 mg/day CsA from day 0 with the intention to reach target levels of 40-80 ng/ml, 42 patients received 2x 200 mg/day CsA from day 4 (target: 100-200 ng/ml), and 38 patients received 2x 300 mg/day from day 4 (target: 100-200 ng/ml). In the retrospective analysis, the individual, patient-specific relation of CsA level to CsA dose (in mg) was found to depend only on height (P = 0.02) and time after transplantation (P < 0.001), but not on body weight (b. wt.). If the CsA dose was expressed in "mg/kg", patients < or = 55 kg b. wt. required nearly twice the doses of patients > or = 75 kg b. wt., whereas the mean CsA requirement was the same when expressed in "mg".(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Cl- and K+ channel currents during the action potential in Chara. Simultaneous recording of membrane voltage and patch currents.

Patch currents in the cell attached-mode and action potentials (AP) have been recorded simultaneously in internodal cells of Chara corallina. The action potentials are closely correlated with transient patch currents. With pipettes containing either 50 mM CaCl2 or 100 mM KCl plus 1 or 5 mM CaCl2, these transients measured up to 100 to 200 pA per patch at zero mV. Transients had a mean duration (time during which the current was > or = half maximum peak amplitude) of about 1 sec, a maximum slope for current rising of about 400 pA sec-1 and a maximum rate of about 100 pA sec-1 for current decay, with no obvious effect of external Ca2+ on either of these parameters. In well-resolved recordings of current transients triggered by an action potential (AP), activities of two types of Cl--conducting channels (15 and 38 pS) have been identified. Since activity of these channels was only observed during action potentials but not upon positive voltage steps, these channels are not directly voltage gated but point to a cytoplasmic gating factor which accumulates during excitation and propagates from excited areas to the patch. A K(+)-conducting channel (40 pS) could be identified as well during an AP, when 100 mM KCl was in the pipette solution. The activity of this channel relaxed at the end of the APs with a time constant of about 3 sec. Stimulated activity of this channel is understood to cause the repolarization overshoot during the final phase of the action potential, whereas the transient activation of the Cl- channels determines the fast voltage changes of the action potential.

Action Potentials↗
PubMed1994

K+ channels of stomatal guard cells: bimodal control of the K+ inward-rectifier evoked by auxin.

The influence of the auxins indole-3-acetic acid (IAA) and 1-napthylene acetic acid (NAA) on K+ channels and their control was examined in stomatal guard cells of Vicia faba L. intact guard cells were impaled with multibarrelled microelectrodes to record membrane potentials and to monitor K+ channel currents under voltage clamp during exposures to 0.1-100 microM IAA and NAA. Following impalements, challenge with either IAA or NAA in the presence of 10 mM KCl resulted in the concerted modulation of at least four different currents with distinct kinetic characteristics and concentration dependencies. Equivalent concentrations of benzoic acid were wholly without effect. Most striking, current carried by inward-rectifying K+ channels (IK,in) exhibited a bimodal response to both IAA and NAA which was reversed on washing the auxins from the bathing medium. The steady-state current was augmented 1.3- to 2-fold at concentrations between 0.1 and 10 microM and antagonized at concentrations near 30 microM and above. Auxin agonism of IK,in was time- and voltage-independent. By contrast, IK,in inactivation at the higher auxin concentrations was marked by a voltage-dependence and slowing of the kinetics for current activation. Inactivation of IK,in by the auxins was relieved when cytoplasmic pH (pHi) was clamped near 7.0 in the presence of 30 mM Na(+)-butyrate. In addition to the control of IK,in, current carried by a second class of (outward-rectifying) K+ channels rose in a monotonic and largely voltage-independent manner with auxin concentrations about 10 microM and above, and IAA and NAA also activated an inward-going current with a voltage dependence characteristic of guard cell anion channels. Further changes in background current were consistent with a limited activation of the H(+)-ATPase. Over the concentration range examined, the auxins evoked membrane hyperpolarizations and depolarizations of up to +/- 12-19 mV, depending on the free-running membrane potential prevailing before auxin additions. Prolonging exposures to 100 microM auxin beyond 3-5 min frequently elicited rapid transitions to voltages near EK as well as regenerative action potentials. However, in every case the voltage response was a predictable consequence of auxin action on the K+ channels and, at 100 microM auxin, on the anion current.(ABSTRACT TRUNCATED AT 400 WORDS)

Benzoates↗
PubMed1994

Synapsin IIa bundles actin filaments.

Synapsins are neuron-specific phosphoproteins associated with small synaptic vesicles in the presynaptic nerve terminal. Synapsin I, which has been demonstrated to bundle F-actin in vitro, has been postulated to regulate neurotransmitter release by cross-linking synaptic vesicles to the actin cytoskeleton. To investigate the possible interaction of synapsin II with actin filaments, we expressed synapsin II in Spodoptera frugiperda and High Five insect cells using a recombinant baculovirus. Purified recombinant synapsin IIa was incubated with F-actin, and bundle formation was evaluated by light scattering and electron microscopy. Synapsin IIa was found to bundle actin filaments. Dose-response curves indicated that synapsin IIa was more potent than synapsin I in bundling actin filaments. These data suggest that synapsin IIa may cross-link synaptic vesicles and actin filaments in the nerve terminal.

Actins↗
PubMed1994

Excellent uricosuric efficacy of benzbromarone in cyclosporin-A-treated renal transplant patients: a prospective study.

Patients on cyclosporin A (CsA) often develop hyperuricaemia and gout. In transplant patients the use of uricosuric drugs for treating hyperuricaemia may be preferable to allopurinol because of the known interaction of the latter with azathioprine. We therefore prospectively studied the uricosuric efficacy of 100 mg benzbromarone (Bbr;Desuric) daily in 25 CsA-treated renal transplant patients with stable graft function and hyperuricaemia (> 359 mumol/l for females, > 491 mumol/l for males). Benzbromarone decreased plasma uric acid from 579 + 18 mumol/l to 313 +/- 24 mumol/l (mean +/- SEM; P < 0.0001) and thereby normalized plasma uric acid in 21 of 25 patients. The remaining four patients had creatinine clearances between 21 and 25 ml/min, the lowest of the entire study group. Mean fractional clearance of uric acid increased from 5.4 +/- 0.4% to 17.2 +/- 1.0% (P < 0.001). The relative decrease of plasma uric acid closely correlated with baseline creatinine clearance (r = 0.67; P < 0.001). CsA trough values were not influenced. None of the patients experienced any significant side-effects. As an unexpected find-ing, urinary uric acid excretion increased from 2082 +/- 175 mumol/24 h to 3233 +/- 232 mumol/24 h after 4 weeks' treatment with benzbromarone. In conclusion, benzbromarone normalized plasma uric acid in all CsA-treated renal transplant recipients with a creatinine clearance > 25 ml/min. Due to its excellent efficacy and lack of significant side-effects, benzbromarone appears to be preferable to allopurinol in CsA-treated renal transplant recipients with a creatinine clearance over 25 ml/min.

Benzbromarone↗
PubMed1994

Peptides derived from the auxin binding protein elevate Ca2+ and pH in stomatal guard cells of Vicia faba: a confocal fluorescence ratio imaging study.

Dual-excitation confocal laser scanning microscopy (CLSM) was used to image the pH-indicator, BCECF, iontophoretically microinjected into stomatal guard cells of Vicia faba during challenge with peptides derived from hydrophilic domains of the maize auxin-binding protein. Only the peptide corresponding to the C-terminal end (Pz151-163) caused significant changes in cytosolic pH, stimulating rapid alkalinisation of 0.4 +/- 0.1 pH units. Cytosolic pH was clamped using the permeant weak acid, butyrate, and this treatment buffered the peptide evoked alkalinisation. In concert with the electrical events monitored at the plasma membrane using whole-cell voltage clamp, this provides strong evidence for a role of [H+] as a signal intermediate in the guard cell transduction network. In preliminary experiments using single-wavelength imaging of the calcium-indicator, Fluo-3, Pz151-163 also stimulated rapid, reversible increases in cytosolic calcium, whilst two other peptides tested had no effect.

Calcium↗
PubMed1994

Long-term benefits and risks of cyclosporin A (sandimmun)--an analysis at 10 years.

To evaluate long-term benefits and risks of CyA therapy in renal transplantation, we analyzed the 10-year experience with all 59 patients who had received a first cadaveric renal graft until August 1983 and were immunosuppressed with CyA. We compared their actual graft survival with that of all 213 patients who had received a first cadaveric graft from 1967 until August 1983, but were immunosuppressed initially with azathioprine and prednisone (AzaP). For comparison of p-creatinine, proteinuria, blood pressure, lipids, uric acid and skin malignancies we evaluated the patients staying unchanged on initial therapy for 10 years (CyA = 12, AzaP = 53). RESULTS. (1) Actual graft survival at 10 years was 34% (20/59) with CyA and 27% (58/213) in AzaP treated patients (intention to treat) (P = .09 = ns). At 1 to 5 years, graft survival was 15% superior with CyA, but after 7 years the survival curve of the CyA-group has closely joined the chronic decline seen in the AzaP group. This behaviour could neither be explained by chronic CyA-nephrotoxicity nor by chronic rejection after switching from CyA to AzaP. (2) P-creatinine at 10 years was significantly (P < .03), but mildly elevated under CyA (130 +/- 52; AzaP = 109 +/- 65). (3) Proteinuria (g/d) at 10 years was not significantly different (CyA = 0.41 +/- 0.58, versus AzaP = 0.83 +/- 1.61). (4) Systolic blood pressure was higher at 10 years under CyA (152 +/- 19) than under AzaP (136 +/-) (P < .02), but diastolic pressure was not (89 +/- 10 versus 84 +/- 12; ns). Antihypertensive drug/patient was twice as high under CyA (1.25 versus 0.64 P < .02). (5) Cholesterol, triglyceride, HDL were not different. 75% of the CyA-patients were steroid free at 10 years, none of the AzaP-patients. (6) P-uric acid was not significantly different in both groups (494 +/- 192 vs 400 +/- 124), but 42% of CyA-patients were on uric acid lowering drug (given after at least one gout attack) as compared to 9% under AzaP (P < .006). (7) Seventeen percent of patients under CyA for 10 years had at least one skin cancer, not different from 15% of AzaP-patients. CONCLUSIONS. The main benefit of CyA was the better graft survival up to 5 years and the chance to stay free of steroids. The main risks of CyA were nephrotoxicity, hypertension and symptomatic hyperuricemia. No difference was found for hyperlipidemia and skin-malignancies.

Antihypertensive Agents↗