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T Meier

Publications and source records attributed to T Meier.

At least 91 records · Page 5Linked to original sources
PubMed1994

Ifosfamide induced depletion of glutathione in human peripheral blood lymphocytes and protection by mesna.

We studied the effects of ifosfamide and major metabolites on intracellular glutathione (GSH) levels in human peripheral blood lymphocytes (PBL). In vitro exposure of PBL to 4-hydroperoxyifosfamide (4-OOH-IF), acrolein or chloroacetaldehyde at 37 degrees C for 60 min led to a concentration dependent depletion of intracellular GSH. The concentration of the three metabolites to cause a 50% depletion of GSH in PBL was in the micromolar range (acrolein: 16 +/- 4 microM; 4-OOH-IF: 22 +/- 9 microM; chloroacetaldehyde: 30 +/- 7 microM). Exposure to ifosfamide, the non-activated drug, had no effects on the intracellular GSH levels. Pretreatment with 4-OOH-IF suppressed dose-dependently the interleukin-2-induced proliferation of PBL. Incubation of PBL together with 2-mercaptoethanesulfonate (mesna) and 4-OOH-IF, acrolein or chloroacetaldehyde prevented the GSH depletion. The protecting effect of mesna in combination with 4-OOH-IF was independent of GSH biosynthesis, because addition of buthionine sulfoximine had no significant influence on this effect. These findings indicate a novel protective mechanism of mesna against intracellular GSH depletion of PBL during exposure to metabolites of ifosfamide.

Acetaldehyde↗
PubMed1994

Prostaglandin E1 versus linsidomine chlorhydrate in erectile dysfunction.

Recent experimental work has demonstrated that nitric oxide (NO) is the neurotransmitter responsible for cavernous smooth muscle relaxation. Different studies on the performance of the direct NO donor linsidomine chlorhydrate (SIN-1) in patients with erectile dysfunction have had conflicting results. We performed a single-blind cross-over trial in 20 patients with erectile dysfunction of mixed etiology comparing prostaglandin E1 (PGE1) to SIN-1 at two different dosages (1 and 2 mg, respectively) in order to determine the effectiveness of SIN-1. PGE1 always achieved the best response, SIN-1 performed statistically significantly poorer irrespective of the dosage used. There were only a few side effects with no significant difference. SIN-1 is not a useful alternative to PGE1 in the treatment of erectile dysfunction.

Adult↗
PubMed1994

[The effect of the husbandry system on comb size and comb color in hens].

The comb size and comb colour of 84 hens (white and brown Hisex), living in battery cages or at free range were investigated. The main question was: does the comb size and colour correlate with the keeping systems i.e. with the quality and intensity of light and the ambient temperature? The results confirm these hypotheses and also show the genetic influence. The crest size of Hisex white hens is larger and paler compared with those of Hisex brown hens. This tendency is more distinct under the conditions of artificial light, less light and higher temperature of the environment in battery cage systems. Comb size and colour are used as a criterium for health and egg production of the hens. The combs are very important for the hen's health for the regulation of the body temperature and for absorbing light and also for the social structure of the flock; the comb form is an essential characteristic to identify the individual animal.

Absorption↗
PubMed1994

[Laparoscopic vs. open surgical lymphadenectomy in prostate cancer. Methodological comparison].

Bilateral laparoscopic pelvic lymph node dissection was performed in 27 consecutive patients with stage B prostatic carcinoma. The first 5 operations (learning phase) were compared with the next 22 procedures and with a group of 20 patients who had undergone conventional open lymphadenectomy previously. Retropubic radical prostatectomy was done in 22 patients with negative nodes. All residual lymphatic tissue was removed. During the learning phase the average operating time was 3 h 40 min. The mean number of laparoscopically removed nodes was 5.8 on both sides. At open operation we found 1.5 residual nodes on the right side and 5.3 residual nodes on the left. In one case one of the residual nodes was positive for tumor. Operating time in the next 22 patients was 2 h 20 min. The number of nodes removed laparoscopically was 8.3 on the right and 7.0 on the left. Residual nodes were found in only 3 patients. None of these nodes was positive for tumor. In both groups the number of nodes removed was greater than in the group of patients who underwent open lymphadenectomy. In one of the first 5 patients immediate open surgery was required because of bleeding. In 1 patient's nodes evidence of Hodgkin disease was found. This was the only patient to develop a lymphatic fistula. There were no lymphoceles. We feel that laparoscopic pelvic lymphadenectomy has a definite learning curve but is a safe staging procedure for prostatic cancer with results equivalent to those of the open operation.

Adult↗
PubMed1993

[Demonstration of intrathecal antibody formation against Borrelia burgdorferi in Lyme neuroborreliosis].

Neurologic complications are common in Lyme borreliosis. In adults in particular, detection of intrathecally formed antibodies to B. burgdorferi is a decisive diagnostic criterion. As in neurosyphilis diagnosis, the specific antibody titer against B. burgdorferi in the CSF is compared with the serum titer by calculating the specific antibody indices, taking into account the disturbed blood/CSF barrier. Deriving from these specific indices, we adapt by dilution the serum IgG level to that in the CSF of the same day, thus allowing for passive diffusion of antibody through the blood/CSF barrier. Determination of the specific antibody titer by indirect immunofluorescence demonstrates intrathecal synthesis of specific antibodies against B. burgdorferi if the CSF titer is higher than in the diluted serum tested in parallel. The individual methods are presented in a group of patients.

Adult↗
PubMed1993

The DNA-dependent RNA-polymerase of Thermotoga maritima; characterisation of the enzyme and the DNA-sequence of the genes for the large subunits.

An improved purification procedure for Thermotoga maritima RNA-polymerase holoenzyme was developed. The enzyme is highly active with poly dAT or T7 phage DNA as template. DNA gyrase was found to be a side product of this RNA-polymerase purification. The genes for the large subunits beta and beta' of RNA-polymerase were cloned and sequenced. The phylogenetic position of T.maritima within the bacterial domain was determined by various methods. It is the lowest bacterial offspring but slightly higher than the chloroplasts.

Amino Acid Sequence↗
PubMed1993

Nucleation of RNA chain formation by Escherichia coli DNA-dependent RNA polymerase.

We have studied the early steps in RNA synthesis. The kinetic behaviour of the nascent RNA, having chain lengths between 3 and 11 bases, and the transcription fidelity were analysed using the bacteriophage T7 A1 promoter. By moving the stop-inducing base at position +12 in the wild-type template in single base steps upstream, a set of closely related templates was constructed which allowed stalling of the complexes in the registers 11, 10, 9 and 8. Using this set of templates sigma-factor release was determined. It occurs when RNA synthesis has proceeded to base position +9. Analysis of the RNA synthesis both with and without heparin yielded the following results: there are three kinds of complexes, (a) the well-known abortively transcribing complex, which is present until the RNA has reached a length of 5 bases, (b) an intermediate complex having RNA chain lengths between 6 and 8 bases, which is stably bound but has high forward as well as back reaction rates, (c) complexes with RNA chains consisting of more than 8 bases, which are stably bound and do not contain the sigma-factor. In general, the likelihood of chain elongation and the stability of the complexes increases with increasing RNA chain length in the early stages of RNA synthesis. Also the transcription fidelity increases correspondingly. Lack of fidelity leads to additional RNA products during the abortive state of transcription. "Read through" of RNA polymerase at stall positions of +8 to +11 also result from misincorporation.

Base Sequence↗
PubMed1993

Organization of the commissural fibers in the adult brain of the locust.

The brain (supraoesophageal ganglion) is the most complex of the segmental ganglia composing the nerve cord of the locusts Schistocerca gregaria and Locusta migratoria. In this paper, we describe the ground plan of the commissures crossing the midline of the brain and propose a nomenclature with the aim of making a complex neuropil more understandable at the level of individual neurons. For developmental and comparative reasons the neuroarchitecture of the brain is related to the neural axis, not to the body axis. We have identified 73 commissural fiber bundles belonging to the adult brain, and these are named according to their location (ventral, dorsal, anterior, posterior, medial) with respect to the central complex as reference point. Reconstructions of identified neurons from intracellular stainings, cobalt backfills, or immunohistochemical studies demonstrate the various configurations in which fibers cross the brain.

Animals↗
PubMed1993

Acetylsalicylic acid inhibition of n-butyl-(4-hydroxybutyl)nitrosamine-induced bladder carcinogenesis in rats.

We examined the effect of acetylsalicylic acid (ASA) on n-butyl-(4-hydroxybutyl)nitrosamine (BHBN)-induced bladder carcinogenesis in male Wistar rats. Of 29 rats that received 0.05% BHBN in their drinking water for 9 weeks, 8 developed bladder cancer. Only 1 out of 29 rats that received 0.1% ASA in their diet for 20 weeks, including the period of BHBN consumption, developed a tumor. That difference is statistically significant. Bladder weight was significantly higher in rats given BHBN than in controls and in rats given both BHBN and ASA. We conclude that ASA inhibits BHBN-induced bladder carcinogenesis.

Animals↗
PubMed1993

Developmental expression of TERM-1 glycoprotein on growth cones and terminal arbors of individual identified neurons in the grasshopper.

The chemoaffinity theory postulates the existence of cell-specific molecular signals that uniquely identify individual developing neurons. Such molecules are thought to promote both accurate axon outgrowth and the formation of correct synaptic connections. To identify candidates for such neuron-specific recognition molecules, we generated monoclonal antibodies that recognize surface-associated antigens expressed by individual identified neurons in the grasshopper embryo. Here we report on a molecular label that is expressed exclusively by two pairs of sibling interneurons in the developing CNS. Our experiments indicate that during axogenesis, this molecule is expressed at the surface of the growth cones of these cells, while during subsequent synaptogenesis, it becomes concentrated at the cells' developing terminal arbors. In both cases the molecule appears to be secreted by the labeled structures. This molecule, which we call TERM-1, is a glycoprotein with a molecular weight of approximately 48 kDa. The highly restricted spatiotemporal expression pattern of TERM-1 implies that individual developing neurons can acquire and retain unique molecular labels that may be important for neuron-specific outgrowth and target recognition.

Animals↗
PubMed1993

[Observations on the course of ejaculation in the posterior urethra].

Nine patients underwent retroperitoneal nerve-sparing lymph node dissection for bilateral nonseminomatous testicular tumours (path. St. I disease). While the isolated lumbar nerves L1, L2, L3 were electrostimulated (30 Hz, 5-20 V), the activity of these seminal vesicles, bladder neck and posterior urethra was recorded by way of suprapubic transvesical sonography and/or endoscopy. Emission started simultaneously on three different levels: contraction of the seminal vesicles in the periphery, bladder neck closure, and opening of the paracollicular space. Contraction of the seminal vesicles extends to the midline; the prostatic urethra closes, starting at the bladder neck. Secretion from the ductuli prostatici (milky) and from the ductucli ejaculatorii (transparent) follow. It was confirmed by the detection of PSA (11,000-21,000 ng/ml) in the ejaculate that prostatic secretion is also present in it. The significance of the postganglionic nerves for emission increased from L1 to L3. In three patients with salvage lymph node dissection the above-mentioned ultrasound monitoring allowed differentiate nerves relevant to emission from those not involved, allowing more comprehensive retroperitoneal resection.

Adolescent↗
PubMed1993

[Excimer laser sclerostomy of secondary glaucoma].

Initial results after nine ab externo sclerotomies on seven patients awaiting enucleation because of intensive pain caused by secondary glaucoma have encouraged us to present the methods used for this technique of fistula construction and the course in these patients. A special applicator permits precise manual positioning of the excimer laser beam (lambda = 308 nm) subconjunctivally at the limbus using a quartz-quartz fiber (diameter: 0.32 mm). The energy applied at the fibertip is 4 mJ per pulse, with a repetition rate of 80 Hz. All patients undergoing the operation, which lasted only a few minutes, were treated as out-patients without a retrobulbar anaesthesia. Because of the minimal irritation of the anterior chamber, only antibiotic treatment was required after the operation. The intraocular pressure immediately decreased to normal levels after the operation without any further glaucoma treatment in five cases. In the other two cases reduced, but still minimally elevated, pressure was recorded. In the case of one heavily inflamed eye, which had been subjected to two operations, pain felt by the patient was relieved when the pressure was reduced. The maximum period of post-operative follow-up so far is over 10 months and the decrease of intraocular pressure has remained adequate without any additional antiglaucoma therapy. In all cases enucleation was avoided.

Glaucoma↗
PubMed1993

[Brain metastases as an initial manifestation of tumor disease].

A retrospective study compared a group of 122 patients with brain metastases from unknown primaries with a second group of 121 patients, who developed brain metastases in the course of a known malignant disease. Special attention was paid to the kind of primary cancer, therapeutic influences and prognostic differences. The results pointed to a late occurrence of brain metastases in breast cancer, no patient with this type of cancer being found in group 1. Melanoma and colorectal cancer were also found predominantly in group 2, whereas lung cancer was the most common cause of metastasis in group 1 and the most frequent cancer in both groups. Clinical course, therapy and outcome showed no significant differences between the two groups. Mean survival time was 4.6 (+/- 6) months for the patient series as a whole. Patients with breast cancer had a significantly higher survival rate than those with other forms of cancer. Localisation and degree of malignancy mainly determine the life-prognosis, the type and intensity of therapy being of secondary importance.

Adult↗
PubMed1992

Immunodetection of biotinylated lymphocyte-surface proteins by enhanced chemiluminescence: a nonradioactive method for cell-surface protein analysis.

Biotinylation and radioiodination have been compared for labeling lymphocyte-surface proteins and the labeled proteins symmetrically immunoprecipitated with antibodies recognizing major lymphocyte markers such as the murine Thy-1, CD25 (the alpha subunit of the interleukin-2 receptor), CD45, and human CD2 glycoproteins. The detection of biotinylated proteins by enhanced chemiluminescence after transfer to nitrocellulose was found to be fast and as efficient as the detection of iodinated proteins by autoradiography. The vectoriality of cell-surface biotinylation was ascertained by two-dimensional electrophoresis of the cellular extract in which the major cytoplasmic proteins were not found biotinylated. This nonradioactive labeling procedure offers a convenient and efficient alternative to radiolabeling of cell surfaces for the biochemical analysis of extracellular domains of membrane proteins.

Animals↗