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Biomedical subjects

M Acca

Publications and source records attributed to M Acca.

24 records · Page 2Linked to original sources

Hypocalcemia and hypomagnesemia in cancer patients.

The aim of this study was to evaluate the incidence of hypocalcemia and hypomagnesemia and the relationship between calcium and magnesium serum levels in 82 hospitalized cancer patients, 61 of whom were in the terminal phase of the disease. The frequency of hypocalcemia and hypomagnesemia was 13.4% and 17.1% respectively. The incidence of hypocalcemia in patients with hypomagnesemia was 28.6%, while in those with normal or high magnesium serum levels it was 10.3%. The lowest magnesium serum level was observed in hypocalcemic patients. It may thus be concluded that hypocalcemia and hypomagnesemia are a frequent complication of malignant tumors mostly in the terminal stage of the disease, and that even hypomagnesemia could contribute to the development of tumor-associated hypocalcemia.

Aged↗

Total reconstitution of active large ribosomal subunits of the thermoacidophilic archaebacterium Sulfolobus solfataricus.

The large ribosomal subunit of the extremely thermoacidophilic archaebacterium Sulfolobus solfataricus has been reconstituted from the completely dissociated RNA and proteins by a two-step incubation procedure at high temperatures. Successful reconstitution requires a preliminary incubation of the ribosomal components for 45 min at 65 degrees C, followed by a second heat-treatment at 80 degrees C for 60 min. Structural reassembly depends upon high concentrations of K+ (300-400 mM) and Mg2+ (20-40 mM) ions. In addition, complete recovery of subunit function stringently requires the presence of a polyamine, thermine (or spermine). The reconstituted archaebacterial subunits are essentially indistinguishable from the native ones by a number of structural and functional criteria.

Archaea↗

Insensitivity of archaebacterial ribosomes to protein synthesis inhibitors. Evolutionary implications.

The effect on Sulfolobus solfataricus (an extremely thermoacidophilic archaebacterium) of selected inhibitors affecting reactions of the polypeptide elongation cycle has been tested by using poly(U) and poly(UG) directed cell-free systems. The results reveal a unique pattern of antibiotic sensitivity of Sulfolobus ribosomes with an inhibitory effect observed for only three of 60 compounds tested. Through comparison with suitable eubacterial and eukaryotic cell-free systems the insensitivity of Sulfolobus ribosomes to most inhibitors of protein synthesis appears to reflect a phylogenetic distinction of ribosome structure, rather than the high temperature conditions of the Sulfolobus assay system. In this respect ribosomes of thermoacidophilic archaebacteria differ not only from their eubacterial and eukaryotic counterparts, but also from ribosomes of archaebacteria belonging to the methanogenic-halophilic branch of the 'third' kingdom. The evolutionary implications of these findings are discussed.

Anti-Bacterial Agents↗

[A digital radiology method for assessing vertebral osteoporosis].

The radiologic identification of vertebral fractures is usually subjective and reproducibility is poor. This paper describes a new digital radiologic method to perform vertebral morphometry, i.e. osteoradiometry (ORM). Lateral radiographs of the thoracic and lumbar spine were obtained in 50 premenopausal women and digitalized by means of a video camera. A special computer software enables to calculate the anterior (Ha), middle (Hm), and posterior (Hp) heights of vertebral bodies (T4-L5) and the morphometric indices of vertebral fractures. ORM reproducibility was assessed by comparing repeated measurements made by two radiologists: the intra- and interobserver variation coefficients (CV) were respectively 1.5% and 2.3% for Hp; 1.3% and 2% for Hm; 1.4% and 2.1% for Ha. The normal range for vertebral dimensions was therefore established. The anterior and posterior heights increased from T4 to L2, but for L3-L5 the posterior height was lower than the anterior height (Ha/Hp > 1). Vertebral heights positively correlated with the standing heights of the subjects (r = 0.2, p < 0.05). Weight and the body mass index (BMI) were not correlated with vertebral heights. These normal values, compared with those found in osteoporosis patients, will allow to assess ORM diagnostic efficacy in identifying vertebral fractures.

Absorptiometry, Photon↗