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Biomedical subjects

J Zimmermann

Publications and source records attributed to J Zimmermann.

At least 37 records · Page 2Linked to original sources
PubMed2000

Soluble guanylate cyclase and cGMP-dependent protein kinase I expression in the human corpus cavernosum.

Nitric oxide (NO) as a mediator in smooth muscle cells causes rapid and robust increases in cGMP levels. The cGMP-dependent protein kinase I has emerged as an important signal transduction mediator for smooth muscle relaxation. The purpose of this study was to examine the existence and distribution of two key enzymes of the NO/cGMP pathway, the cGMP-dependent kinase I (cGK I) and the soluble guanylate cyclase (sGC) in human cavernosal tissue. The expression of the enzymes were examined in corpus cavernosum specimens of 23 patients. Eleven potent patients suffered from penile deviations and were treated via Nesbit's surgical method. Nine long-term impotent patients underwent implantation of flexible hydraulic prothesis. Three potent patients underwent trans-sexual operations. Expression of the sGC and cGK I were examined immunohistochemically using specific antibodies. In all specimens of cavernosal tissue a distinct immunoreactivity was observed in different parts and structures. We found a high expression of sGC and cGK I in smooth muscle cells of vessels and in the fibromuscular stroma. The endothelium of the cavernosal sinus, of the cavernosal arteries, and the cavernosal nerve fibers showed an immunoreactivity against sGC. The distribution analysis of cGK I revealed a predominately vesicular localization in smooth muscle cells. The examination of the endothelium showed no clear immunoreactivity against cGK I. There was no distinct difference in immunoreactivity and cellular distribution between potent and impotent patients.

Actins↗
PubMed2000

Synthesis of 1-aldofosfamide-perhydrothiazines.

Aldofosfamide-perhydrothiazine derivatives are a new class of prodrugs which spontaneously, with half-life times of 2 to > 12 h hydrolyse to the corresponding aldophosphamide in aquous solution. Synthesis of 1-aldofosfamide-perhydrothiazine (N,N'-(2-chloroethyl)-phosphorodiamide-2-(2'-[4'-carboxy-1',3'- perhydrothiazinyl])-ethylester) and a derivative, in which one 2-chlorethyl group of the alkylating function is substituted by a mesyl-ethyl-group (N-(2-Chloroethyl)-N'-(methanesulphonylethyl)- phosphorodiamide-2-(2'-[4'-carboxy-1',3'-perhydro-thiazinyl] )-ethylester), is described.

Antineoplastic Agents↗
PubMed2000

Activation of progelatinase B by membranes of human polymorphonuclear granulocytes.

Isolated human granulocyte plasma membranes contain progelatinase B. The binding of progelatinase B to the membrane, however, is relatively weak, and a considerable part of progelatinase B can be removed by simply washing the membrane with buffer. This detachment does not depend on the ionic strength of the buffer, indicating that electrostatic forces do not play an important role in the binding of progelatinase B to the membrane. A complete removal of progelatinase B is achieved by chromatography of neutrophil membranes on gelatin-agarose. The plasma membrane of human granulocytes activates added progelatinase B. This activation is inhibited by soybean trypsin inhibitor and is thus performed by membrane bound serine proteinases. In contrast to other reports that claimed an important role of elastase in activating progelatinase B, we found that this activation is mostly inhibited by chymostatin and not by elastatinal and is thus primarily due to cathepsin G. Proteinase 3 was shown to activate progelatinase B as efficient as neutrophil elastase, i. e. much weaker than cathepsin G. Binding of cathepsin G and elastase to the neutrophil membrane does not change their ability to activate progelatinase B. However, cathepsin G, the most potent activator of the three neutrophil serine proteinases, is only a weak activator, when compared to stromelysin-1. This, as well as only a weak binding of progelatinase B, make it doubtful that activation of membrane-bound progelatinase B by membrane-bound serine proteinases is of significant physiological importance.

Cathepsin G↗
PubMed2000

[The biologically equivalent dose (BED): how solid is the calculation of this factor? A consideration of margins of error of biologically equivalent dose].

To predict the effect on tumours in radiotherapy, especially relating to irreversible effects, but also to realize the retrospective assessment the so called L-Q-model is relied on at present. Internal specific organ parameters, such as alpha, beta, gamma, Tp, Tk, and rho, as well as external parameters, so as D, d, n, V, and Vref, were used for determination of the biologically equivalent dose BED. While the external parameters are determinable with small deviations, the internal parameters depend on biological varieties and dispersions: in some cases the lowest value is assumed to be delta = +/- 25%. This margin of error goes on to the biologically equivalent dose by means of the principle of superposition of errors. In some selected cases (lung, kidney, skin, rectum) these margins of error were calculated exemplarily. The input errors especially of the internal parameters cause a mean error delta on the biologically equivalent dose and a dispersion of the single fraction dose d dependent on the organ taking into consideration, of approximately 8-30%. Hence it follows only a very critical and cautious application of those L-Q-algorithms in expert proceedings, and in radiotherapy more experienced based decisions are recommended, instead of acting only upon simple two-dimensional mechanistic ideas.

Algorithms↗
PubMed1999

Octreotide (somatostatin analog) treatment reduces endothelial cell dysfunction in patients with diabetes mellitus.

Octreotide is a long-acting somatostatin analog that has been shown to have various effects in diabetes. This study was performed to evaluate whether octreotide affects the vascular complications of diabetes mellitus. Albuminuria and serum thrombomodulin were used as markers of vascular and renal dysfunction. We studied the effect of octreotide in 27 patients with insulin-dependent diabetes mellitus (IDDM). They received 200 microg octreotide per day over a period of 6 months. As a marker of endothelial cell damage, we measured the serum thrombomodulin level. We also measured urinary albumin excretion, hemoglobin A1c (HbA1c), insulin-like growth factor-1 (IGF-1), and other parameters. IGF-1 decreased from 123 ng/mL before treatment to 114 ng/mL after 6 months of octreotide treatment (P = .009), while no significant change was observed in the unblinded control group (from 103 ng/mL to 102 ng/mL after 6 months of treatment). Urinary albumin excretion in patients with macroalbuminuria declined from 1,124 mg/L before octreotide treatment to 556 mg/L after 6 months of treatment (P < .05), whereas no change was observed in the control group. There was also a reduction of the plasma thrombomodulin level from 61.8 ng/mL to 46.1 ng/mL (P < .07) after 6 months of treatment. Furthermore, HbA1c decreased from 8.75% +/- 1.27% to 8.12% +/- 1.23% (P < .07) after octreotide treatment.

Adult↗
PubMed1999

Inflammation enhances cardiovascular risk and mortality in hemodialysis patients.

BACKGROUND: Atherosclerosis, a major problem in patients on chronic hemodialysis, has been characterized as an inflammatory disease. C-reactive protein (CRP), the prototypical acute phase protein in humans, is a predictor of cardiovascular mortality in the general population. We hypothesize that several of the classic, as well as nontraditional, cardiovascular risk factors may respond to acute phase reactions. An activated acute phase response may influence or predict cardiovascular risk. METHODS: In 280 stable hemodialysis patients, serum lipids, apolipoproteins (apo) A-I and B, lipoprotein(a) [Lp(a)], fibrinogen, and serum albumin (Salb) were determined in relation to CRP and serum amyloid A (SAA), two sensitive markers of an acute phase response. Mortality was monitored prospectively over a two year period. RESULTS: Serum CRP and SAA were found to be elevated (more than 8 and more than 10 mg/liter, respectively) in 46% and 47% of the patients in the absence of clinically apparent infection. Patients with elevated CRP or SAA had significantly higher serum levels of Lp(a), higher plasma fibrinogen, and lower serum levels of high-density lipoprotein cholesterol, apo A-I, and Salb than patients with normal CRP or SAA. The rise in Lp(a) concentration was restricted to patients exhibiting high molecular weight apo(a) isoforms. During follow-up, 72 patients (25.7%) had died, mostly due to cardiovascular events (58%). Overall mortality and cardiovascular mortality were significantly higher in patients with elevated CRP (31% vs. 16%, P < 0.0001, and 23% vs. 5%, P < 0.0001, respectively) or SAA (29% vs. 19%, P = 0.004, and 20 vs. 10%, P = 0.008, respectively) and were also higher in patients with Salb of lower than 40 g/liter (44% vs. 14%, P < 0.0001, and 34% vs. 6%, P < 0.0001, respectively). Univariate Cox regression analysis demonstrated that age, diabetes, pre-existing cardiovascular disease, body mass index, CRP, SAA, Salb, fibrinogen, apo A-I, and Lp(a) were significantly associated with the risk of all-cause and cardiovascular mortality. During multivariate regression analysis, SAA, fibrinogen, apo A-I, and Lp(a) lost their predictive values, but age and CRP remained powerful independent predictors of both overall death and cardiovascular death. CONCLUSION: These results suggest that a considerable number of hemodialysis patients exhibit an activated acute phase response, which is closely related to high levels of atherogenic vascular risk factors and cardiovascular death. The mechanisms of activated acute phase reaction in patients on chronic hemodialysis remain to be identified. A successful treatment of the inflammatory condition may improve long-term survival in these patients.

Acute-Phase Reaction↗
PubMed1998

Retractions.

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Retraction Notice↗
PubMed1997

CGP 57148, a tyrosine kinase inhibitor, inhibits the growth of cells expressing BCR-ABL, TEL-ABL, and TEL-PDGFR fusion proteins.

CGP 57148 is a compound of the 2-phenylaminopyrimidine class that selectively inhibits the tyrosine kinase activity of the ABL and the platelet-derived growth factor receptor (PDGFR) protein tyrosine kinases. We previously showed that CGP 57148 selectively kills p210BCR-ABL-expressing cells. To extend these observations, we evaluated the ability of CGP 57148 to inhibit other activated ABL tyrosine kinases, including p185BCR-ABL and TEL-ABL. In cell-based assays of ABL tyrosine phosphorylation, inhibition of ABL kinase activity was observed at concentrations similar to that reported for p210BCR-ABL. Consistent with the in vitro profile of this compound, the growth of cells expressing activated ABL protein tyrosine kinases was inhibited in the absence of exogenous growth factor. Growth inhibition was also observed with a p185BCR-ABL-positive acute lymphocytic leukemia (ALL) cell line generated from a Philadelphia chromosome-positive ALL patient. As CGP 57148 inhibits the PDGFR kinase, we also showed that cells expressing an activated PDGFR tyrosine kinase, TEL-PDGFR, are sensitive to this compound. Thus, this compound may be useful for the treatment of a variety of BCR-ABL-positive leukemias and for treatment of the subset of chronic myelomonocytic leukemia patients with a TEL-PDGFR fusion protein.

Animals↗
PubMed1997

[Cardiovascular risk factors in diabetic nephropathy].

BACKGROUND: Diabetic nephropathy is associated with increased cardiovascular mortality. This may be contributed to by changes in plasma lipids, fibrinogen and hemorheology. Cardiovascular autonomic dysfunction, which is related to an increased incidence of arrhythmic death, may also play a role. PATIENTS AND METHODS: Therefore, we investigated in 58 IDDM-patients with none (n = 28), incipient (albuminuria 30 to 300 mg/day, n = 11) and overt clinical nephropathy (albuminuria > 300 mg/day, n = 19) plasma concentrations of lipoproteins and fibrinogen, plasma viscosity, erythrocyte aggregation and erythrocyte rigidity. Assessments of neuropathy included tibial nerve motor conduction velocity, perception of vibration, beat-to-beat variation during rest and during forced respiration, heart-rate response to Valsalva maneuver and heart-rate response to standing (30:15). RESULTS: Patients with clinical overt nephropathy had, compared to those without nephropathy, significantly higher concentrations of LDL-cholesterol, triglycerides and fibrinogen, significantly lower concentrations of HDL-cholesterol and significantly higher plasma viscosity, erythrocyte aggregability and erythrocyte rigidity. Regarding the assessments of neuropathy we found in patients with nephropathy, compared to those without nephropathy, significantly reduced tibial nerve motor conduction velocity, reduced perception of vibration thresholds and reduced heart rate variability during rest, during forced respiration, in response to Valsalva maneuver and in response to standing. In diabetic patients with microalbuminuria erythrocyte aggregability and erythrocyte rigidity were significantly higher and heart rate variability during rest was significantly lower than in patients without nephropathy. CONCLUSION: In clinical overt nephropathy there is an aggregation of different cardiovascular risk factors, namely, disturbances in lipoprotein concentrations, increased fibrinogen concentration and disturbances in hemorheology. Furthermore marked deterioration in peripheral and autonomic cardial nerve function in these patients is evident accounting for a part of the greatly increased cardiovascular mortality of these patients.

Adult↗
PubMed1997

Automated cycle sequencing with Taquenase: protocols for internal labeling, dye primer and "doublex" simultaneous sequencing.

This paper describes automated cycle sequencing protocols for internal labeling, dye primer and "doublex" simultaneous sequencing using Taquenase, a new genetically modified DNA polymerase with increased thermostability. Sequencing performance both with labeled and unlabeled primer yields uniform unambiguous signals up to the resolution limit of the sequencing gels. Primer walking with internal labeling was successfully performed on Pl-derived artificial chromosome (PAC) constructs with 130-kb inserts. Taquenase, a commercially available modified thermostable sequencing enzyme (delta 280, F667Y Taq DNA polymerase), incorporates a variety of fluorescent dNTPs carrying fluorescein isothiocyanate, TexasRed or Cy5 labels during the cycle-sequencing process with higher efficiency than other thermostable DNA polymerases. Comparison to other modified Taq DNA polymerases suggests that the particular N-terminal deletion of Taquenase rather than the presence of the F667Y mutation is responsible for the efficient incorporation and extension of labeled dNTPs. Taquenase makes feasible highly accurate "doublex" simultaneous cylce sequencing on both strands of template DNA with two internal labels or two dye-labeled primers in combination with the EMBL-2-dye DNA sequencing system, ARAKIS, or with two commercial DNA sequencers. It allows up to 2000 bases at > 99% accuracy to be determined in a single reaction.

DNA↗
PubMed1997

Inflammation, dyslipidemia and vascular risk factors in hemodialysis patients.

Cardiovascular complications account for more than 50% of death in hemodialysis patients. Strong and independent predictors of mortality or cardiovascular complications are low levels of serum albumin, high plasma C-reactive protein and lipoprotein(a), plasma proteins that are described to function as negative or positive acute phase reactants. Further prominent and known risk factors that contribute to the increased incidence of atherosclerosis in hemodialysis patients are disorders in lipoprotein metabolism and elevated plasma fibrinogen concentrations. The latter has also been described to increase following acute or chronic inflammation. The main metabolic abnormality of the lipoprotein profile is a delayed catabolism of triglyceride-rich apoB-containing lipoproteins caused by a decreased activity of lipolytic enzymes. Inhibition of lipoprotein lipase activity by cytokines or parathyroid hormone impedes conversion of very-low-density lipoprotein to low-density lipoprotein, resulting in remnant accumulation and hypertriglyceridemia. Another acute phase condition, namely, acute myocardial infarction, results in a similar pattern of dyslipidemia and coagulation disorder. In summary, the acute phase response deeply influences serum lipids and lipoproteins as well as other atherogenic acute phase proteins in hemodialysis patients. Appreciation of acute phase lipoprotein changes is essential for accurate diagnosis of dyslipidemias, proper design of future clinical studies, and correct interpretation of published data.

Acute-Phase Proteins↗
PubMed1996

Sequencing and analysis of 51 kb on the right arm of chromosome XV from Saccharomyces cerevisiae reveals 30 open reading frames.

We have sequenced a region of 51 kb of the right arm from chromosome XV of Saccharomyces cerevisiae. The sequence contains 30 open reading frames (ORFs) of more than 100 amino acid residues. Thirteen new genes have been identified. Thirteen ORFs correspond to known yeast genes. One delta element and one tRNA gene were identified. Upstream of the RPO31 gene, encoding the largest subunit of RNA polymerase III, lies a Abf1p binding site. The nucleotide sequence data reported in this paper are available in the EMBL, GenBank and DDBJ nucleotide sequence databases under the Accession Number X90518.

Base Sequence↗
PubMed1996

"Doublex" fluorescent DNA sequencing: two independent sequences obtained simultaneously in one reaction with internal labeling and unlabeled primers.

The novel "doublex" DNA sequencing technique that makes it possible to obtain simultaneously two independent sequences from one sequencing reaction with the use of unlabeled primers and internal labeling is described. The different sequencing products are labeled in parallel with fluorescein-15-dATP and Texas red-5-dCTP present in the same tube. The characteristics of T7 DNA polymerase are exploited to ensure that only either of the labeled dNTPs is incorporated into the corresponding sequencing products. Specificity of labeling is ensured by the selection of primers. One of the unlabeled primers is chosen to be followed by an "A," the other by a "C" to be incorporated immediately downstream from the primer binding site. The doublex sequencing technique is applicable to the simultaneous sequencing of either the same DNA template/strand or a mixture of different templates. Combinations of unlabeled and labeled primers in the same sequencing reaction are also possible. The two sequences can be determined in parallel and on-line in the same lanes of a gel with a novel automated DNA sequencer, which was previously described for use with labeled primers.

Autoanalysis↗
PubMed1996

Inhibition of the Abl protein-tyrosine kinase in vitro and in vivo by a 2-phenylaminopyrimidine derivative.

Oncogenic activation of Abl proteins due to structural modifications can occur as a result of viral transduction or chromosomal translocation. The tyrosine protein kinase activity of oncogenic Abl proteins is known to be essential for their transforming activity. Therefore, we have attempted to identify selective inhibitors of the Abl tyrosine protein kinase. Herein we describe an inhibitor (CGP 57148) of the Abl and platelet-derived growth factor (PDGF) receptor protein-tyrosine kinases from the 2-phenylaminopyrimidine class, which is highly active in vitro and in vivo. Submicromolar concentrations of the compound inhibited both v-Abl and PDGF receptor autophosphorylation and PDGF-induced c-fos mRNA expression selectively in intact cells. In contrast, ligand-induced growth factor receptor autophosphorylation in response to epidermal growth factor (EGF), insulin-like growth factor-I, and insulin showed no or weak inhibition by high concentrations of CGP 57148. c-fos mRNA expression induced by EGF, fibroblast growth factor, or phorbol ester was also insensitive to inhibition by CGP 57148. In antiproliferative assays, the compound was more than 30-100-fold more potent in inhibiting growth of v-abl-transformed PB-3c cells and v-sis-transformed BALB/c 3T3 cells relative to inhibition of EGF-dependent BALB/MK cells, interleukin-3-dependent FDC-P1 cells, and the T24 bladder carcinoma line. Furthermore, anchorage-independent growth of v-abl- and v-sis-transformed BALB/c 3T3 cells was inhibited potently by CGP 57148. When tested in vivo, CGP 57148 showed antitumor activity at tolerated doses against tumorigenic v-abl- and v-sis-transformed BALB/c 3T3 cells. In contrast, CGP 57148 had no antitumor activity when tested using src-transformed BALB/c 3T3 cells. These findings suggest that CGP 57148 may have therapeutic potential for the treatment of diseases that involve abnormal cellular proliferation induced by Abl protein-tyrosine kinase deregulation or PDGF receptor activation.

3T3 Cells↗
PubMed1996

Phenylamino-pyrimidine (PAP) derivatives: a new class of potent and selective inhibitors of protein kinase C (PKC).

Phenylamino-pyrimidines represent a novel class of inhibitors of the protein kinase C with a high degree of selectivity versus other serine/threonine and tyrosine kinases. Steady state kinetic analysis of N-(3-[1-imidazolyl]-phenyl-4-(3-pyridyl)-2-pyrimidinamine (5), which showed potent inhibitory activity, revealed competitive kinetics relative to ATP. The adjacent H-bond acceptor of the pyrimidine moiety next to an H-bond donor of the phenylamine was found to be crucial for inhibitory activity. N-(3-Nitro-phenyl)-4-(3-pyridyl)-2-pyrimidinamine (7) preferentially inhibited PKC-alpha (IC50 = 0.79 microM) and not the other subtypes tested. The inhibition constants of PKC-alpha and the antiproliferative effect on T24 human bladder carcinoma cells showed a qualitative correlation, although with some exceptions.

Aniline Compounds↗
PubMed1996

Effects of a selective inhibitor of the Abl tyrosine kinase on the growth of Bcr-Abl positive cells.

The bcr-abl oncogene, present in 95% of patients with chronic myelogenous leukemia (CML), has been implicated as the cause of this disease. A compound, designed to inhibit the Abl protein tyrosine kinase, was evaluated for its effects on cells containing the Bcr-Abl fusion protein. Cellular proliferation and tumor formation by Bcr-Abl-expressing cells were specifically inhibited by this compound. In colony-forming assays of peripheral blood or bone marrow from patients with CML, there was a 92-98% decrease in the number of bcr-abl colonies formed but no inhibition of normal colony formation. This compound may be useful in the treatment of bcr-abl-positive leukemias.

Animals↗