Biomedical subjects

M Beil

Publications and source records attributed to M Beil.

At least 19 recordsLinked to original sources

PubMed1992

Proliferating cell nuclear antigen (PCNA) in atypical and malignant meningiomas.

Because it is not easy to determine the tumor status of meningiomas by current diagnostic procedures, we investigated these tumors immunohistochemically using the monoclonal antibody PC 10. This antibody recognizes a fixation- and processing-resistant epitope of the proliferating cell nuclear antigen (PCNA), which is a 36-KD nuclear antigen associated with the cell cycle. We studied paraffin-embedded and formalin-fixed tissue specimens of a group of 21 atypical/malignant meningiomas together with 18 benign meningiomas. PCNA staining results were compared with the mean number of silver-stained nucleolar organizer region-associated proteins (AgNORs), tumor grading, and mitotic indices of these tumors. The percentage of PCNA-positive cells was found to range between 0.1% and 40%, irrespective of the tumor grade. When all tumors were collectively considered, no positive correlation was found between PCNA scores and histologic grading and only a weak one between PCNA score and mitotic index. A higher correlation was seen between AgNOR counts and tumor grading. Our results suggest that PCNA labeling and histologic grading seem to be independent parameters. The correlations found between AgNOR counts and tumor grading should be substantiated in further series.

Antigens, Nuclear↗

PubMed1992

Nucleolar organizer region-associated proteins in cancer cells. Quantitative investigations on gliomas, meningiomas, urinary bladder carcinomas and pleural lesions.

Using a modified silver staining technique, we investigated nucleolar organizer region-associated proteins (AgNORs) in paraffin sections of 156 neoplastic tissues and other lesions, including gliomas (n = 41), meningiomas (n = 20), urinary bladder carcinomas (n = 58), and neoplastic and reactive lesions of the mesothelium of the pleural cavity (n = 37). We found significant differences in the mean number and area of AgNORs per nucleus between nonanaplastic and anaplastic astrocytomas. In meningiomas AgNOR analysis may be useful to distinguish between mostly benign tumors (grade 1 tumors) and atypical ones. Urinary bladder carcinomas exhibited a statistically significant increase in both AgNOR number and area as the grade of malignancy increased. Diagnostically useful differences in the AgNOR configuration between inflammatory and neoplastic processes were found for mesothelial lesions. In general, a higher grade of malignancy correlated with an increase in the AgNOR number. This was accompanied by an increase in the total AgNOR area per nucleus, irrespective of whether the size of the individual AgNORs had changed.

Antigens, Nuclear↗

PubMed1992

[AgNOR in neurooncology].

By means of a standardized silver staining technique, nucleolar organizer region-associated proteins (AgNORs) have been demonstrated in paraffin sections of 41 astrocytomas and glioblastomas and 19 meningiomas. Computer-assisted image analysis was used to measure AgNORs together with other nuclear features. Significant differences in number and configuration of AgNORs have been found between non-anaplastic astrocytomas and anaplastic gliomata. In meningiomas, tumours with signs of increased proliferative activity and usual non-anaplastic ones could be discriminated using AgNOR data.

Astrocytoma↗

PubMed1991

Computer-assisted image analysis of nucleolar organizer regions (NORs): a pilot study of astrocytomas and glioblastomas.

Computer-assisted image analysis was used to measure nucleolar organizer regions (NORs) of 22 astrocytomas and glioblastomas. Image analysis provides reproducible information about number and size of NORs together with further karyometric data, which can be compared and processed with other patient-related data. Our study exhibits a statistical relationship between number and size of NORs and malignancy of the measured gliomas.

Astrocytoma↗

PubMed1991

[Measurement of the number, size and location of AgNORs in histologic sections of astrocytomas and bladder carcinoma].

Nucleolus organizer regions (NORs) are associated with proliferative activity of tumors. An image analysis method is presented in this paper by which it is possible to analyze NOR location within the nucleus and relative to each other. Several features which characterized locations were measured in 20 urinary bladder carcinomas, eight astrocytomas, and two glioblastomas. Correlations were found to exist between those features, on the one hand, and tumor malignancy, on the other. They were particularly close in astrocytoma. Mean distance among NORs and closeness to the nuclear membrane were found to increase, as well, along with aggravating malignancy. As to the urinary bladder carcinomas examined, an unambiguous difference was found to exist between G 1 and G 1-2 carcinomas.

Astrocytoma↗

PubMed1991

[AgNORs in cells of urothelial carcinoma of the bladder. A quantitative study using automatic microscopic image analysis].

Biopsies taken from 52 cases of urinary bladder carcinoma together with samples collected from 6 controls were stained to visualize AgNORs, using a technique modified by the authors of this paper after its first introduction to histological practice by Ploton et al. (1986) as well as by Crocker and Nar (1987). AgNORs were quantitatively analyzed by means of an image processing system and a programme written by the authors' team for this particular purpose. The configuration was such that information was provided on the number and size of AgNORs. AgNORs were found to go up numerically along with aggravating malignancy, means values being 1.7/cell nucleus in Grade 1 urothelial carcinomas (controls being 1.6), 2.6 in Grade 2, and 3.3 in Grade 3. Mean AgNOR sum areas in the three above tumor groups were 3.4 microns 2, 7.4 microns 2, and 12.8 microns 2 (controls being 2.6 microns 2). Analysis of AgNORs, consequently, should provide prognostically relevant information helpful in more effective grading of urinary bladder carcinoma.

Carcinoma, Transitional Cell↗

PubMed1991

Renal actions of a new adenosine agonist, CGS 21680A selective for the A2 receptor.

This study compares the renal actions of the A2 selective adenosine agonist, CGS 21680A, with the A1 selective adenosine agonist, N6-cyclopentyladenosine (CPA), and the nonselective agonist, 5'-N-ethylcarboxamide adenosine (NECA), in the anesthetized dog. Initial receptor binding studies in dog brain demonstrated that CPA and CGS 21680A were selective for the A1 and A2 adenosine receptor, respectively, whereas NECA displayed slightly greater affinity for A1 than A2 adenosine receptors in the canine brain. Intravenous infusion of CGS 21680A (0.25 and 2.5 micrograms/kg/min) decreased blood pressure (BP) and increased heart rate (HR). CGS 21680A transiently increased renal blood flow (RBF) and either did not change or, at the highest dose infused, decreased glomerular filtration rate (GFR). Both urine volume (UV) and urinary sodium excretion (UNaV) also were decreased by CGS 21680A. At the lowest infusion rate (0.025 micrograms/kg/min) CGS 21680A produced a slowly developing increase in RBF, no change in GFR and a significant decrease in sodium excretion. Intravenous infusion of CPA (15 micrograms/kg/min) lowered BP and HR RBF and GFR. UNaV, UV and renin release also were inhibited by CPA. At a lower infusion rate (2.5 micrograms/kg/min), CPA markedly inhibited UNaV in the absence of a significant change in either BP or renal hemodynamic parameters. Infusion of NECA (0.01 and 0.1 micrograms/kg/min) lowered BP but did not change HR. Furthermore, RBF was increased by NECA, whereas UV and UNaV were inhibited in the absence of a change in GFR. These results may be explained by the relative selectivity of each analog for A1 or A2 adenosine receptors.

Adenosine↗

PubMed1991

Intrarenal actions of the new adenosine agonist CGS 21680A, selective for the A2 receptor.

The purpose of this study was to define the direct intrarenal actions of the new adenosine agonist CGS 21680A (hydrochloride "A" salt of (2-[p-2-carboxyethyl)phenethylamino]5'-N-ethyl-carboxamido adenosine), which is selective for the A2 receptor. CGS 21680A was infused into the left renal artery, while simultaneously measuring blood pressure (BP) and parameters of renal function from both the left and right kidneys. At doses higher than 0.05 micrograms/kg/min, CGS 21680A appeared to leak from the circulation of the infused kidney in pharmacologically significant quantities, inasmuch as BP fell and renal blood flow was increased and renal vascular resistance decreased in the noninfused contralateral kidney. At doses of 0.025 to 0.05 micrograms/kg/min, CGS 21680A appeared localized to the renal circulation, because neither BP nor any measured parameter of contralateral renal function was altered. Intrarenal infusion of 0.025 to 0.05 micrograms/kg/min of CGS 21680A increased renal blood flow but not glomerular filtration rate leading to a fall in the filtration fraction. Urine volume and urinary sodium excretion were unaffected by selective intrarenal infusion of CGS 21680A. Plasma renin activity and renin secretion rate were also not altered significantly by intrarenal infusion of 0.05 micrograms/kg/min of CGS 21680A. In contrast plasma renin activity increased significantly in response to the intrarenal infusion of 0.075 micrograms/kg/min of CGS 21680A, a dose which leaked from the kidney and lowered BP. The results presented suggest that the new adenosine agonist CGS 21680A exerts a direct intrarenal effect on renal hemodynamics, but does not affect urine volume or sodium excretion or directly influence renin release.

Adenosine↗

PubMed1978

Role of alpha-adrenergic receptors in exercise-induced bronchoconstriction.

The role of alpha-adrenergic receptors in exercise-induced bronchoconstriction (EIB) was studied. 9 asthmatic patients with a marked degree of EIB (group I) and 6 asthmatic patients with no or a less severe EIB (group II) were investigated and compared with 8 healthy control persons. Pulse rate, airway resistance and end-expiratory thoracic gas volume were measured at rest and immediately and 15 min after exercise. Group I subjects showed a significant inhibition of EIB after alpha-adrenergic blockade with phentolamine (10 mg as aerosol) and after cholinergic blockade with an atropine-ester (60 mg as aerosol). In 7 of 9 patients who had received phentolamine, and in 3 of 6 patients who had received atropine-ester, the EIB was completely suppressed. In group II the administration of propranolol (40 mg orally) produced a significant increase in EIB. The effect of propranolol could be inhibited by the addition of alpha-adrenergic blockade with phentolamine (10 mg as aerosol). The control subjects had no measurable EIB, even after the administration of propranolol (40 mg orally). It is concluded that, in addition to the vagal system, an activated alpha-adrenergic system is involved in the phenomenon of EIB.

Adult↗

PubMed1977

Plasma catecholamines in exercise induced bronchoconstriction.

Plasma nor-epinephrine (NE) and epinephrine (E) levels at rest and immediately after exercise were estimated in 8 patients with asymptomatic extrinsic allergic bronchial asthma. The patients had a normal airway resistance at rest and developed a marked bronchoconstriction (EIB) during exercise, which could be prevented by previous alpha-adrenergic blockade with phentolamine. In 7 control persons NE and E levels were measured also after beta-adrenergic blockade with propranolol. The following results were obtained: 1. At rest NE levels showed no significant differences between the groups. After exercise an increase of NE was observed in all groups, but in patients, even after phentolamine, and in normals after propranolol the increase was significantly higher than in the normal group within the control test. 2. No significant differences between the groups were found in E levels at rest and after exercise. Exercise caused no significant increase of E levels, except in the normals after propranolol application. 3. No significant correlation existed between NE levels and the increase of airway resistance after exercise. It is concluded that during exercise in asthmatics the sympathetic activity is enhanced, but the provocation of an EIB does not seem to be mediated by enhanced plasma NE levels.

Adrenergic alpha-Antagonists↗

PubMed1977

[Effects of a new cardioselective beta-adrenergic blocker (atenolol) on airway resistance in chronic obstructive disease (author's transl)].

The effect of 4-(2-hydroxy-3-isopropylamino-propoxy)-phenyl acetamide (atenolol, ICI 66 082) (100 mg) on airway resistance (Rt), thoracic gas volume (IGV), pulse rate and blood pressure was tested as a double blind study in 20 patients with chronic obstructive airway disease in comparison to propranolol (80 mg) and placebo. The effect on pulse rate was equipotent, but when using propranolol the mean increase of Rt was larger and increased Rt-values (greater than or equal 1.5 cm H2O/l/sec) were observed more frequently than after atenolol application. These differences were significant for 1 h after application. The augmentation of IGV was significantly larger after propranolol than after atenolol. We conclude that atenolol, in comparison to propranolol, has a relative but no specific cardioselectivity.

Adult↗

PubMed1976