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Biomedical subjects

R Verna

Publications and source records attributed to R Verna.

51 records · Page 3Linked to original sources
PubMed1983

Na+/K+ ATPase and cell growth--III: Enzymatic activity in cultured and EGF stimulated HeLa cells.

1. The behaviour of Na+/K+ ATPase during the growth of ectodermal tumoral cells (HeLa) has been investigated. 2. Besides spontaneously growing cells, also samples stimulated with EGF have been tested. 3. The content of--SH groups in the homogenates of both the untreated and the EGF stimulated samples has been tested. 4. Results show a decrease of enzymatic activity during the culture of neoplastic cells and an enhancement of this behaviour in the EGF stimulated cells due to the action of the hormone on--SH groups.

Cell Division↗
PubMed1980

Effects of prazosin on the cAMP system in the spontaneously hypertensive rat (SHR) aorta.

3',5'-adenosine monophosphate (cAMP), adenylate cyclase and cAMP-phosphodiesterase (PDE) activity were measured in aorta homogenates from normal and spontaneously hypertensive rats (SHR) during treatment with prazosin, an antihypertensive drug. cAMP levels were lower in SHR than in normal rats. In SHR prazosin treatment induced marked inhibition of PDE activity thus causing an increase in cAMP levels; adenylate cyclase activity remained unaffected. This effect was only present for the first 32 days of drug administration.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1975

Hormone responsiveness of plasma membrane-bound enzymes in normal and regenerating rat liver.

The hormonal responsiveness of plasma membrane-bound enzymes (Na-+-K-+)-ATPase and adenylate cyclase has been investigated in normal and regenerating rat liver. (Na-+-K-+)-ATPase basal activity is not affected by surgery and only slightly affected by partial hepatectomy; its response to epinephrine and cyclic AMP is decreased only 15 h after hepatectomy. Adenylate cyclase activity of plasma membranes from untreated animals is stimulated by parathyroid hormone and thyroxine; partial hepatectomy increased basal activity as well as the stimulation exerted by the aforementioned hormones, when glucagon and epinephrine sensitivity is essentially unaltered.

Adenosine Triphosphatases↗
PubMedDate not supplied

Age-related changes in blood and liver lipids of male Wistar rats.

The results of this study indicate that the age-dependent plasma cholesterol increase observed in male Wistar rats is correlated with changes in both the distribution of high-density lipoprotein fractions and the storage of hepatic cholesterol. Specifically, the lipoprotein distribution showed a significant increase in the proportion of HDL(1) and a symmetrical decrease in both the HDL(2) and HDL(3) fractions during the 3 month to 18 month age period. There were no significant changes in the very-low density and low-density lipoprotein fractions. The chemical composition of lipoproteins showed many age-related variations, especially in the proportion of cholesteryl ester and in the distribution of HDL subfractions. A study of fatty acyl composition of the major lipid classes showed that, within cholesteryl ester found in liver, there was an increase in the proportion of saturated fatty acids. Polyunsaturated fatty acids increased in the cholesteryl esters found in high-density lipoproteins of older rats. These observations suggest that the age-dependent accumulation of body cholesterol occurs by a reduced catabolism of HDL(1) fraction, and modifications in plasma and liver lipids.

Journal Article↗
PubMedDate not supplied

Na+/K+ ATPase and cell growth IV: a metabolic marker of human brain tumors?

The activity of total, Mg++ dependent and Na+/K+ ATPase as well as the content of cAMP and cGMP in homogenates of human brain tumors have been investigated. Results are compared to values obtained from normal cortices. Na+/K+ ATPase and cAMP are decreased with a close relationship with the degree of malignancy, while Mg++ dependent activity is lower than in normal cortex but with no differences between the various tumors, and cGMP is unaffected. We conclude with a discussion on the metabolism of brain tumors and the suggestion of Na+/K+ ATPase activity as a marker of the malignancy of neoplastic growth.

Astrocytoma↗
PubMedDate not supplied

[Invasive thermometry and prognostic thermometry in radiological hyperthermia].

The term radiological hyperthermia is used to describe the exposure of biological tissues to temperatures just above physiological ones, namely between 42 and 45 degrees C. A machine for hyperthermia (SAPIC SV03 produced by Aeritalia, Caselle, Turin) is been experimentally used at the authors' institute. The present study aims to analyse the technical and qualitative aspects of temperature control using invasive and previsional thermometry. The term invasive thermometry is used to describe the insertion of small teflon catheters into the biological body through which thermometric probes are introduced to control deep temperature. Previsional thermometry is the phrase used to describe the computer simulation of hyperthermic treatment, starting from knowledge of the tissue to be heated and the type of applicator used. The simulated treatment and the real temperature measured are then compared in order to optimize the treatment used.

Equipment Design↗
PubMedDate not supplied

Combined modality therapy for laryngeal and hypopharyngeal cancer.

In recent years, the improvement in results in terms of survival in the treatment of laryngeal and hypopharyngeal cancer at the same stage has been rather poor. Therefore, oncologists have tried to improve the quality of life through a decrease in morbidity while not decreasing the treatment efficacy. In particular, the objective was to preserve with noninvasive procedures the anatomy and function of the larynx and hypopharynx while not affecting the possible cure. The refinement on diagnostic, surgical and anesthetic procedures, the potential of modern radiotherapy, the acquisition of new knowledge in medical oncology have allowed the planning of combined modality therapy protocols aimed at organ preservation in many patients. Concurrent radiation and chemotherapy in patients with locally advanced disease is a clinical problem still under study. Results of some phase I and III studies have shown the efficacy of radiochemotherapy, at times with a non negligible toxicity involving healthy tissues, but with a real effective improvement in survival and organ preservation in laryngeal and hypopharyngeal cancer.

Combined Modality Therapy↗
PubMedDate not supplied

Brachytherapy and local control.

Locoregional control of primary tumor is fundamental to cure since only in one third of patients the onset of distant metastases is the major cause of therapeutic failure. Thus recently, all therapeutic approaches aimed at the enhancement of locoregional control have been considered with growing interest. More particularly, brachytherapy alone or in combined modality therapy as an important option in the local treatment of various malignant tumors, has been widely used; this being related to the now available information on dose-rate, remote after-loading procedures, the new, safe and handy radionuclides and computerized dosimetry systems which allow a more accurate and rapid dose calculation. These advances have led to a wider application of brachytherapy. Together with the classical indications for head and neck and cervical tumors, brachytherapy plays now a well-established role in the treatment of breast, brain, gastrointestinal, genitourinary, soft tissue lung and eye tumors.

Bile Duct Neoplasms↗