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Biomedical subjects

M Beer

Publications and source records attributed to M Beer.

At least 145 records · Page 8Linked to original sources
PubMed1989

[The clinical value of preoperative staging of bladder and prostatic cancers with nuclear magnetic resonance and computerized tomography].

To evaluate the diagnostic value of preoperative staging of bladder cancer and cancer of the prostate, CT and NMR scans of 45 histologically defined tumors of the bladder and the scans of 24 patients with radical prostatectomy were compared. Lack of extravesical spread was imaged correctly by NMR in all cases of urothelial cancer (pT1-pT3a). CT diagnosis failed in 39%. False-negative results were obtained in 2 of 5 invading tumors (pT3b) by NMR and in 3 of 5 by CT. Extraglandular spread of cancer of the prostate was diagnosed with an accuracy rate of 79% by NMR and of 46% by CT. The diagnostic value for detection of pelvic lymph node metastases had a low-sensitivity rate of 26% in NMR and of 22% in CT.

Aged↗
PubMed1989

[The clinical value of NMR tomography for retroperitoneal diagnosis].

NMR-tomography is a noninvasive diagnostic alternative to conventional imaging modalities. For clinical purpose there is no significant improvement in staging of kidney tumors and lymphnode metastases. The diagnostic value for complicated cysts and adrenal tumors is superior to all alternative imaging modalities as CT and sonography. Tumors of vena cava could be staged with an accuracy rate of 100%.

Adrenal Gland Neoplasms↗
PubMed1989

[Clinically controlled study of success of lateral and thermo-mechanical Gutta-percha condensation].

76 root canal treated teeth were followed up within 2 years after treatment with the help of the periapical index PAI and the root canal filling index WKF-I. The root canals were obturated with gutta-percha and Sealer according to lateral or thermom chanical condensation. Treatment was successful in 26 of the lateral condensated and in 25 of the thermomechanical condensated cases. The thermomechanical condensation method represents an alternative method for filling root canals for those endodontists who are well practiced in this method and ensures a high success rate at exact indication positions. Intense practice on extracted teeth prior to clinical application is a strong prerequisite. The lateal condensation method is the root canal filling technique of choice for the general dental practice.

Gutta-Percha↗
PubMed1989

Testicular prostheses.

Testicular prosthesis implantation is a generally simple and low-morbidity method of softening the psychological trauma suffered by patients faced with the loss of a testis.

Adolescent↗
PubMed1988

In vitro selectivity of agonists and antagonists for beta 1- and beta 2-adrenoceptor subtypes in rat brain.

A radioreceptor binding assay was developed to determine the selectivity of beta-adrenoceptor agents in rat brain. This was achieved by using the highly selective unlabelled antagonists CGP 20712A and ICI 118-551 to block beta 1- or beta 2-sub-populations respectively in rat cerebral cortex membranes. This permitted the selective labelling of beta-adrenoceptors with the antagonist (-)-[125I]pindolol. Using this method, compounds could be routinely screened and selectivity profiles for binding in the CNS determined with a high degree of sensitivity and resolution.

Adrenergic beta-Agonists↗
PubMed1988

Electron microscopic visualization of sites of nascent DNA synthesis by streptavidin-gold binding to biotinylated nucleotides incorporated in vivo.

Biotinylated nucleotides (bio-11-dCTP, bio-11-dUTP, and bio-7-dATP) were microinjected into unfertilized and fertilized Xenopus laevis eggs. The amounts introduced were comparable to in vivo deoxy-nucleoside triphosphate pools. At various times after microinjection, DNA was extracted from eggs or embryos and subjected to electrophoresis on agarose gels. Newly synthesized biotinylated DNA was analyzed by Southern transfer and visualized using either the BluGENE or Detek-hrp streptavidin-based nucleic acid detection systems. Quantitation of the amount of biotinylated DNA observed at various times showed that the microinjected biotinylated nucleotides were efficiently incorporated in vivo, both into replicating endogenous chromosomal DNA and into replicating microinjected exogenous plasmid DNA. At least one biotinylated nucleotide could be incorporated in vivo for every eight nucleotides of DNA synthesized. Control experiments also showed that heavily biotinylated DNA was not subjected to detectable DNA repair during early embryogenesis (for at least 5 h after activation of the eggs). The incorporated biotinylated nucleotides were visualized by electron microscopy by using streptavidin-colloidal gold or streptavidin-ferritin conjugates to bind specifically to the biotin groups projecting from the newly replicated DNA. The incorporated biotinylated nucleotides were thus made visible as electron-dense spots on the underlying DNA molecules. Biotinylated nucleotides separated by 20-50 bases could be resolved. We conclude that nascent DNA synthesized in vivo in Xenopus laevis eggs can be visualized efficiently and specifically using the techniques described.

Animals↗
PubMed1987

Independent regulation of beta 1- and beta 2-adrenoceptors.

1 The down-regulation of beta-adrenoceptors has been postulated as a biochemical marker of antidepressant efficacy. Here we demonstrate that chronic treatment with desipramine down-regulates beta 1-adrenoceptors in rat cerebral cortex and that beta-adrenoceptor subtypes can be independently regulated by treatment with different beta-adrenoceptor agonists. 2 Desipramine, (+/-)-clenbuterol, prenalterol, corwin (20 mg kg-1 daily) and corwin (10 mg kg-1 daily) were administered to male, Sprague-Dawley rats, over eight days, by means of osmotic Alzet pumps placed subcutaneously and removed 24 h before analysis. Control rats received vehicle only. The beta 1- and beta 2-adrenoceptor populations were measured in cerebral cortex by a modified (-)-[125I]-pindolol receptor binding assay. 3 The conventional antidepressant, desipramine, preferentially down-regulated beta 1-adrenoceptors whereas the non-selective beta-adrenoceptor agonist (+/-)-clenbuterol preferentially down-regulated beta 2-adrenoceptors. The beta 1-selective partial agonist, prenalterol, up-regulated beta 1-adrenoceptors perhaps acting more as an antagonist than as an agonist. Finally, neither dose of corwin had any significant effect on beta-adrenoceptor number.

Adrenergic beta-Agonists↗
PubMed1987

Adjuvant intravesical chemotherapy of superficial bladder cancer with monthly doxorubicin or intensive mitomycin. A comparison of two consecutive series.

120 patients with the first occurrence of TNM stage Ta or T1 bladder carcinoma were given adjuvant intravesical treatment in 2 consecutive series. The first 60 received doxorubicin monthly for 6 months, then on the 9th and 12th month following surgery. The second series was given mitomycin weekly for 2 months, then monthly to the end of the first year. Median follow-up is 48 months in the first series and 15 in the second. In the doxorubicin group, 28 patients had recurrences. The recurrence rate is 1.86/100 patient-months. Seventeen of these first relapses occurred within the first year. In the 'intensive' mitomycin series, where 36 patients were observed for 12 months or more, 3 relapsed. The recurrence rate to date is 0.35. The relapse-free survival probability at 12 months is 75% in the first series and 93% in the second. Treatment was stopped due to toxicity in 4 patients in the doxorubicin group and in 10 of the mitomycin group.

Administration, Intravesical↗
PubMed1987

[Value of percutaneous diagnosis and therapeutic procedures in obstructive uropathy following kidney transplantation].

Postrenal obstruction is a severe complication after renal transplant. To evaluate side effects and effectiveness we analyzed 71 ategrade pyeloureterographies (AP) and 30 percutaneous and open nephropyelostomies. AP shows a sensitivity of 93% and proved thereby its superiority to alternative diagnostic procedures. Also percutaneous pyelostomy proved its reliability in therapy of obstructive disease. Comparing side effects to those in normal kidneys we found a higher incidence of bleeding (17%). There was no severe complication with loss of graft. In 6 cases of obstructive disease we could prevent an operation by temporary percutaneous nephrostomy. Long term nephrostomy allows to evaluate the function of the kidney accurately which may not be possible until after 1-2 months.

Diagnosis, Differential↗
PubMed1987

[Value of nuclear magnetic resonance tomography in the staging of tumors of the urinary bladder].

The accuracy of magnetic resonance imaging (MRI) and computed tomography (CT) in the staging of bladder tumors was evaluated in 46 patients. In the T-staging MRI was superior to CT. With MRI 38 out of the 46 tumors were correctly staged into the four groups T0, T1-T3a, T3b and T4. With CT this classification was only possible in 28 cases. The main advantages of MRI were the capability for multiplanar imaging, which improved evaluation of the bladder base and the bladder dome, as well as a better differentiation between tumor recurrency and fibrosis. In the evaluation of adenopathy MRI and CT proved to be equal and demonstrated a sensitivity of 50%.

Carcinoma, Transitional Cell↗
PubMed1986

Distribution of mass within native thick filaments of vertebrate skeletal muscle.

The distribution of mass within the vertebrate skeletal thick filament has been determined by scanning transmission electron microscopy. Thick and thin filaments from fresh rabbit muscle were mixed with tobacco mosaic virus (TMV), fixed with formaldehyde, dried onto thin carbon films and viewed in a computer-linked microscope. Electron scattering data from both TMV and thick filaments were analysed with reference to the long axis of the particles so that the distribution of mass within the particles could be determined. While TMV appeared to be a uniform rod at the resolution employed (4.3 nm), the thick filament was clearly differentiated along its length. M-line remnants at the centre of the filament were flanked by regions of low mass per unit length, corresponding to the bare zone of the filament, and then by the more massive cross-bridge regions. The mass per unit length was approximately constant through most of the cross-bridge zone and declined at the filament tips, in a manner consistent with a constant number of myosin molecules per 14.3 nm interval (crown) throughout the cross-bridge zone. Fourier analysis of the data failed to detect the expected 43 nm periodicity of C-protein. The total mass of the thick filament was 184 Mdalton (s.e.m., 1.6 X 10(6); n = 70). The mass of adhering M-line proteins was highly variable but, on average, was about 4 Mdalton. The total mass of the filament and the mass distribution in the cross-bridge zone are consistent with three myosin molecules per crown.

Actin Cytoskeleton↗
PubMed1986

Phase I study of oral idarubicin given with a weekly schedule.

Thirty one patients with solid tumors were entered into a phase I trial with idarubicin, a new anthracycline antibiotic with oral antitumor activity in animals. The drug was scheduled to be given for 4 consecutive weeks at doses ranging from 10 to 20 mg/m2. Leukopenia was the dose-limiting toxicity. Thrombocytopenia was occasionally seen. Since several patients could not receive the third and fourth administrations of the drug at 17.5 and 20 mg/m2, higher doses were administered only for 2 consecutive weeks. With this schedule, the maximum tolerated dose was 25 mg/m2 and leukopenia was again the dose-limiting toxicity. With both schedules, myelosuppression was highly variable and could not be related to prior therapy, bone or liver metastases, or performance status. Other toxicities were mild to moderate and were dominated by nausea and vomiting which were observed in 29% of the patients. Alopecia and mucositis were unfrequent and cardiac toxicity was not observed. Starting doses of 15 mg/m2 for 4 consecutive weeks or 20 mg/m2 for 2 consecutive weeks could be proposed for oral phase II studies with idarubicin, under careful pharmacokinetic monitoring.

Administration, Oral↗