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Biomedical subjects

M Hartmann

Publications and source records attributed to M Hartmann.

At least 253 records · Page 14Linked to original sources
PubMed1995

Replication and persistence of coxsackieviruses B3 in human fibroblasts.

Although in some cases a carrier state of Coxsackieviruses in human fibroblasts was described, the persistence mechanism has remained unknown. Our results demonstrate a replication of Coxsackievirus B3 (CVB3) in diploid human fibroblasts that is dependent on the virus strain as well as on the cell line involved. Two CVB3 Nancy strains could be multiplied over more than 10 passages in cell line H, whereas CVB3 strains SH"C" and SH"W" did not longer form infectious virus following several passages in these fibroblasts. None of the CVB3 strains replicated in cell lines J and K after a few passages. These results were not influenced by variations of culture conditions such as duration of incubation (3 or 7 days), temperature (33 or 37 degrees C) or application of trypsin. In line H, only 3-5 per cent of human fibroblasts were virus-infected. This was demonstrated by 1. antigen evidence by immunofluorescence, 2. determination of infectious centres, and 3. virus reproduction in dependence on MOI of the virus. We observed a carrier state of CVB3 Nancy strains over 16 cell passages in line H fibroblasts infected once. As shown in virus passage experiments, only few cells were productively infected. An addition of specific anti-CVB3 antiserum terminated this persistent infection. Generally, no cytopathic effect was observed. However, in one case a cell destruction by CVB3 Nancy "P" at the end of the life-time of the carrier cells could be found. This virus caused a complete cytopathic effect during more than 10 passages in line H and could still be neutralized by CVB3-specific antiserum.

Animals↗
PubMed1995

Diaphragmatic paresis in newborns due to phrenic nerve injury.

Phrenic nerve lesions as a result of birth trauma have been reported as a cause of acute respiratory distress infrequently. We report recent diagnostic and therapeutic experiences in four newborns with birth-traumatic phrenic nerve injury: one bilaterally, and three unilaterally, all right-sided. In each case, mechanical ventilation was required for at least 16 days. Ultrasound examination of the diaphragm and phrenic nerve conduction studies turned out to be the diagnostic methods of choice. Spontaneous recovery occurred in two children and two became asymptomatic after operative treatment. One improved after plication of diaphragm and one after autologous nerve transplantation.

Birth Injuries↗
PubMed1995

[Rhinosinusitis in AIDS patients].

We examined microbic infections and topical immunity in 36 AIDS patients with rhinosinusitis (AIDS CDC stage IV b-d) who had an average serum CD4 count of 90/microliters. We also examined the presence of the HIV genome in nasal mucous. Microbiological examination revealed an increased number of fungal infections in addition to bacterial infections with multiresistant strains. There was no evidence of CD4-T cells or HIV reverse transcriptase. The size of study was too small to permit generalised conclusions about the infectious risk of nasal mucous.

AIDS-Related Opportunistic Infections↗
PubMed1995

Expression of the c-kit proto-oncogene and its ligand stem cell factor (SCF) in normal and malignant human testicular tissue.

Recent findings suggest an important role of the proto-oncogene c-kit, a surface membrane receptor of the tyrosine kinase family, and its ligand stem cell factor (SCF) in normal spermatogenesis and possibly in the pathogenesis of certain testicular germ cell tumors. To further investigate this potential role, the expression of c-kit and SCF was studied in normal and malignant human testicular tissue specimens at the mRNA and protein level by Northern blot analysis and immunohistochemistry, respectively. The detection of the c-kit receptor in normal human germ cells and its natural ligand SCF in Sertoli cells suggests the presence of a local trophic regulatory system that may be active in human spermatogenesis. Additionally, c-kit expression was detected in the seminoma but not in the nonseminoma subtype of human testicular germ cell tumors (GCT). Stem cell factor was not expressed at the mRNA level in tissue from either subtype of GCT as determined by Northern blot analysis; however, the protein was detected immunohistochemically in the cytoplasm of rare tumor cells.

Cell Adhesion Molecules↗
PubMed1995

Detection of Tropheryma whippelii DNA in a patient with AIDS.

A case of an AIDS patient infected with the Whipple's disease bacterium, Tropheryma whippelii, is reported. A DNA fragment with sequence specificity for the 16S rRNA gene of the bacterium was detected by PCR in a duodenal biopsy specimen from a 55-year-old male patient with AIDS and diarrhea. The biopsy specimen contained periodic acid-Schiff stain-positive macrophages which did not, however, resemble the sickleform-particle-containing cells characteristic of Whipple's disease. This observation raises two possibilities: either the patient had a coincidence of AIDS and Whipple's disease or Tropheryma whippelii acted as an opportunistic pathogen in this immunodeficient patient. The latter explanation is of interest in light of the ongoing discussion of immunologic abnormalities as predisposing factors for Whipple's disease.

AIDS-Related Opportunistic Infections↗
PubMed1995

Lack of interaction between pantoprazole and digoxin at therapeutic doses in man.

Substituted benzimidazole inhibitors of the gastric H+/K+ATPase may interact with the cytochrome P450 enzyme system and alter the pharmacokinetics of coadministered drugs. On the other hand, changes in intragastric pH might alter the absorption of other drugs. The primary aim of the present study was to determine whether pantoprazole modifies the steady-state serum concentrations of orally administered digoxin. Secondary aims were the influence of digoxin on the pharmacokinetics of pantoprazole as well as safety and tolerability. Eighteen healthy volunteers received a single oral dose of pantoprazole (40 mg) and serum concentrations were determined. Three to 10 days later, subjects received in a single-blind, randomized, crossover fashion oral beta-acetyldigoxin (0.2 mg) twice daily and concomitant oral pantoprazole (40 mg) or placebo once daily for 5 days. Serum concentrations of pantoprazole and digoxin were determined on day 5. Primary characteristics for confirmative assessment of no interaction were AUC and Cmax of digoxin. Lack of interaction in the sense of equivalence was concluded for both digoxin (with and without pantoprazole) and pantoprazole (with and without digoxin) as the 90%-confidence intervals of the respective AUC- and Cmax-ratios were within the equivalence range of 0.8-1.25. Pantoprazole did not influence the characteristic ECG modifications (T-wave) caused by digoxin. Both drugs were well tolerated and no adverse events or clinically relevant alterations in vital signs or clinical laboratory parameters were observed during treatment. In conclusion, pantoprazole and digoxin may be administered concomitantly without the need for dose adjustment.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

[Transparency of intraocular lenses and contrast sensitivity].

A loss of contrast sensitivity was noted in patients with inciplent cataracts and also in artephakias. As all these patients displayed normal visual acuity (6/6-6/9), our data suggest that the use of high-contrast optotypes is insufficient. Low-contrast optotypes are recommended for testing visual acuity in the above mentioned groups of patients.

Aged↗
PubMed1995

Acrosome reaction and fertility.

The acrosome reaction is important for fertilization. To diagnose this reaction the simple gelatin lysis test, the triple-stain technique or labelling with lectins can be used. The role of pentoxifylline in enhancing the acrosome reaction remains to be determined.

Acrosome↗
PubMed1994

The thermostability of natural variants of bacterial plasminogen-activator staphylokinase.

Three natural variants (wild-type staphylokinase, [R36G, R43H]staphylokinase, and [G34S, R36G, R43H]staphylokinase) of the bacterial plasminogen-activator staphylokinase, a 136-amino-acid protein secreted by certain Staphylococcus aureus strains, have been characterized. These variants differ at amino acid positions 34, 36 and 43 only, and have a very similar plasminogen-activating capacity and conformation in solution, as revealed by fluorescence spectroscopy, dynamic light scattering and circular dichroism. However, the thermostability of these variants is significantly different. At 70 degrees C and 0.5 mg protein/ml, irreversible inactivation occurred with apparent half-life (t1/2) values 0.54 +/- 0.13, 0.81 +/- 0.20 and 3.7 +/- 0.7 h (mean +/- SEM) for wild-type staphylokinase, [R36G, R43H]staphylokinase, and [G34S, R36G, R43H]staphylokinase, respectively, with corresponding values at 0.08 mg/ml of 5.3 +/- 1.4 h and 11 +/- 2.0 h for wild-type staphylokinase and [R36G, R43H]staphylokinase, respectively. Dynamic light-scattering measurements indicated that inactivation was associated with protein aggregation, which precluded accurate determination of transition temperatures and enthalpies of unfolding. 0.08-0.34 mg/ml [G34S, R36G, R43H]staphylokinase, however, did not aggregate at 70 degrees C but underwent unfolding as revealed by a 20% increase in the Stokes' radius and a 30% decrease in circular dichroism. The unfolding was reversible upon cooling and was associated with full recovery of functional activity. Thus, these natural variants of staphylokinase have a different sensitivity to thermal inactivation, that is mediated by reversible unfolding of the protein and concentration-dependent irreversible aggregation. [G34S, R36G, R43H]staphylokinase, the most resistant natural variant, has a stability approaching the minimal requirements for pasteurization, which would facilitate its development for clinical use.

Amino Acid Sequence↗
PubMed1994

Functional properties of recombinant staphylokinase variants obtained by site-specific mutagenesis of methionine-26.

Variants of recombinant staphylokinase (Sak) were produced by site-specific mutagenesis of the unique Met-26 residue and purified to homogeneity from the cell extract of transformed E. coli. The desired mutations were confirmed by cDNA and amino-acid sequence analysis. Sak-M26L, Sak-M26C, Sak-M26R, Sak-M26V and Sak-M26A were selected for further analysis on the basis of their plasminogen activating activity. The specific fibrinolytic activities of Sak-M26L, Sak-M26C and Sak were comparable (76,000 +/- 10,000, 75,000 +/- 2400 and 78,000 +/- 9700 HU/mg, respectively; mean +/- S.E., n = 3 or 4). Active site exposure in equimolar (4.5 microM) mixtures plasminogen at room temperature was more rapid with Sak-M26L than with Sak (quantitative exposure within 4 min and 8 min, respectively). Activation of 1 microM plasminogen by catalytic amounts (5 nM) of Sak-M26L initially appeared to be somewhat faster, but comparable 50 to 60% activation was obtained within 30 min. In contrast, Sak-M26R and Sak-M26V were virtually inactive, did not form active complexes with plasminogen and did not activate plasminogen. The catalytic efficiencies for plasminogen activation were comparable for plasmin-Sak-M26L, plasmin-Sak-M26C and plasmin-Sak (0.14 microM-1 s-1, 0.16 microM-1 s-1 or 0.12 microM-1 s-1, respectively). Comparable dose-dependent lysis of 0.06 ml 125I-fibrin labeled human plasma clots submerged in 0.3 ml human plasma was obtained with Sak-M26L, Sak-M26C and Sak (concentration required for 50% lysis in 2 h, EC50, of 17 +/- 1.6 nM, 19 +/- 1.4 nM and 14 +/- 2.5 nM, respectively), whereas Sak-M26R or Sak-M26V were inactive. Sak-M26A did not form a stable complex with plasminogen, as shown by gel filtration. These data establish that substitution of the unique Met residue in position 26 of the Sak sequence with Leu or Cys has little or no influence on its plasminogen activating or fibrinolytic potential. In contrast, substitution of Met-26 with either Arg or Val results in total loss of the functional activity. Thus, the amino acid in position 26 of Sak appears to be of crucial importance for the activation of plasminogen by staphylokinase.

Amino Acid Sequence↗
PubMed1994

The binding properties of two antitumor ruthenium(III) complexes to apotransferrin.

The interaction of two ruthenium(III) complexes exhibiting high anticancer activity, namely trans-indazolium(bisindazole)tetrachlororuthenate(III) (ru-ind) and trans-imidazolium(bisimidazole)tetrachlororuthenate(III) (ru-im), with human serum apotransferrin has been investigated through spectroscopic and chromatographic techniques with the ultimate goal of preparing adducts with good selectivity for cancer cells. Whereas the binding of ru-im to human serum apotransferrin takes several hours, ru-ind, the less toxic complex, gives rise to a well defined 2:1 complex within a few minutes. We have ascertained that ru-ind binding occurs around the iron binding sites; binding does not occur in the absence of bicarbonate, and this anion dictates the kinetic and mechanistic characteristics of protein binding of ru-ind. The two ruthenium(III) complexes do not behave as iron(III) complexes, e.g. Fe(EDTA) or Fe(nitrilotriacetate), which lose their respective ligands when binding apotransferrin, but the N-heterocycles remain attached to the metal in the protein-bound species. Reversion of binding is obtained by acidification in the presence of chelators such as citrate or ATP. In comparison with cisplatin and its deactivation by serum proteins, our results indicate that other metal complexes such as ru-ind could use transferrin as a drug delivery system. Furthermore, the rapid protein binding of ru-ind seems to be related to a lower toxicity while still exhibiting high antitumor activity.

Antineoplastic Agents↗
PubMed1994

HPV DNA in autopsy-derived material from multiple metastases of a cervical carcinoma.

Fresh tissue from primary tumor and a metastasis of a cervical carcinoma and 13 autopsy-derived tissue specimens of the same patient were analyzed for HPV DNA by Southern blot hybridization and PCR. Primary tumor and 7 of 10 histologically proven distant metastases contained HPV 16 DNA by Southern blot. PCR detected HPV 16 in all 10 metastases and in 2 of 3 additional tumor-free autopsy-derived tissues. The restriction pattern was identical in all HPV-positive lesions and only slight variations in copy number occurred. Two-dimensional gel electrophoresis showed the viral DNA fully integrated in the cellular genome without any difference between primary tumor and metastasis. The relevance of HPV also for the metastatic spread of the malignant disease is indicated by its conserved presence in multiple distant metastases of cervical carcinoma.

Adult↗
PubMed1994

Insulin receptors in syncytiotrophoblast and fetal endothelium of human placenta. Immunohistochemical evidence for developmental changes in distribution pattern.

The localisation of insulin receptors (IR) was investigated on cryosections of human non-pathologic first trimester and full term placentae by indirect immunohistochemistry with three different monoclonal antibodies (MABS). In placentae from 6 to 10 weeks postmenstruation (p-m.), only syncytiotrophoblast was stained, predominantly that of mesenchymal villi and syncytial sprouts, which are areas of high proliferative activity. In placentae from 11 to 14 weeks p-m., endothelial cells commenced to react with the IR MABS and the syncytiotrophoblast was less intensely labelled than at weeks 6 to 10 p-m. In term placentae, the microvillous membrane of the syncytiotrophoblast showed only patches of weak immunoreactivity. In contrast, the endothelial cells in the placenta but not in the umbilical cord were strongly stained. The amniotic epithelium in the chorionic plate and fibroblasts in the stroma were conspicuously labelled. The data indicate: (1) the receptor density on villous syncytiotrophoblast decreases and that of fetal endothelium increases' throughout gestation; (2) syncytiotrophoblast of human term placentae expresses a low level per unit area of surface IR; and (3) the majority of IR in human term placentae is located in fetal endothelium. Apart from yet unknown functional effects of maternal and fetal insulin at the placental barrier, the results suggest a growth promoting effect on the trophoblast of maternal insulin in first trimester as well as developmental effects of fetal insulin on the feto-placental vessels at term.

Antibodies, Monoclonal↗
PubMed1994

Fungicides and photochemistry: photodegradation of the azole fungicide penconazole.

In order to examine the photostability of the fungicide penconazole (1-(2,4-dichloro-beta-propylphenethyl)-1H-1,2,4-triazole, 1) in the field, model experiments with organic solvents were performed. Photodegradation (lambda > 280 nm) of penconazole was found to be more efficient in isopropanol and cyclohexane solution than in the presence of cyclohexene. Photolysis in isopropanol and cyclohexane resulted in considerable formation of 1-(4-chloro-beta-propylphenethyl)-1H-1,2,4-triazole (2) and 5H,6H-(1,2,4-triazolo)-[5,1-a]-9-chloro-6-propyl-isoquinoline (3). Furthermore, photodehalogenation of 3 yielded traces of 5H,6H-(1,2,4-triazolo)-[5,1-a]-6-propyl-isoquinoline (4) and, in the presence of isopropanol 5H,6H-(1,2,4-triazolo)-[5,1-a]-9-(2-hydroxy-2-methylethyl)-6-propyl- isoquioline (5). Additionally, a lot of polar products were found in high yields which could not be isolated and characterized individually. In the presence of cyclohexene, on the other hand, photodecomposition and photodehalogenation to photoproduct 2 were found to be the main degradation pathways and photoproduct 3 was only detected as a trace component.

Chromatography, High Pressure Liquid↗
PubMed1994

The value of the AgNOR staining method in identifying carcinoma in situ testis.

An early and reliable diagnosis is necessary in order to have the chance of a curative therapy of Carcinoma in situ testis (Cis). Forty-six testicular biopsies were investigated to assess the value of the AgNOR staining method in comparison to placental alkaline phosphatase (PLAP) immunostaining. Both methods provided corresponding results and identical tumor cells were recognized in serial sections. The mean AgNOR counts per nucleus were 26.86 (19-52, SD: 2.68) for CIS cells, 8.18 (5-14, SD: 2.20) for spermatogonia and 12.96 (9-18, SD: 2.44) for Sertoli cells, without the counts overlapping within these three groups. Even single CIS cells are easily and reliably recognizable by their typical AgNOR pattern and their high AgNOR count per nucleus. The independent estimation of 9 testicular biopsies with the AgNOR staining method and the PLAP immunostaining correspondingly revealed 7 biopsies with CIS. Two biopsies lacked tumor cells. The AgNOR staining method can be recommended as an additional diagnostic tool in identifying CIS, because of the short and convenient staining procedure, low costs and the applicability on formalin-fixed and paraffin-embedded material.

Alkaline Phosphatase↗
PubMed1994

High yield production and purification of recombinant staphylokinase for thrombolytic therapy.

Recombinant plasmids were constructed in which the signal sequence of the sak42D and the sakSTAR staphylokinase genes were replaced by an ATG start codon and which express staphylokinase under the control of a tac promoter and two Shine-Dalgarno sequences in tandem. Induction of transfected E. coli TGl cells in a bacterial fermentor produced intracellular staphylokinase representing 10 to 15% of total cell protein. Gram quantities of highly purified recombinant staphylokinase were obtained from cytosol fractions by chromatography, at room temperature, on SP-Sepharose and on phenyl-Sepharose columns, with yields of 50 to 70 percent. The material, at a dose of 4 mg/kg, did not produce acute reactions or affect body weight in mice. Intravenous administration of 10 mg SakSTAR over 30 minutes in five patients with acute myocardial infarction induced complete coronary artery recanalization, without associated fibrinogen degradation. However, neutralizing antibodies appeared in the plasma of all patients within 12 to 20 days. Thus, the present expression and purification method for recombinant staphylokinase yields large amounts of highly purified mature protein (approximately 200 mg per liter fermentation broth) suitable for a more detailed clinical investigation of its potential as a thrombolytic agent.

Base Sequence↗