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Biomedical subjects

A Asti

Publications and source records attributed to A Asti.

7 recordsLinked to original sources

beta amyloid-induced disruption of ionic balance: studies on the isolated frog labyrinth.

The beta-amyloid peptide (A beta) is a key player in the pathogenesis of Alzheimer's disease. Although its mechanisms of action are not fully elucidated, a disruption of ionic homeostasis has been suggested, and A beta aggregation in fibrils seems correlated to its toxic potential. In the present work, we studied the effects of different A beta fragments on the activity of frog ampullar nerve fibers. Our results show that A beta fragments are able to reduce ampullar nerve responses, with a potency correlated to their fibrillogenic capability. This study may have clinical implications, since vestibular problems are often reported in Alzheimer patients, and provide a model for the dissection of A beta effects in a simple multicomponent system.

Action Potentials↗

Unexpected finding of barium sulphate on the surface of a microspinal catheter.

During a study with a scanning electron microscope to evaluate the structure of microspinal catheter after its removal from subarachnoid space, we found an unusual case. The observation with the microscope of the tip of a catheter removed at the end of an operation for hip replacement in a old female showed the presence of grounded particles with a crystal shape covering the outer surface. Further analysis of this material with an Energy-Dispersive Spectrometer (EDS) showed that it was barium. The patient performed a large bowel barium enema 8 months earlier for a painful syndrome to the lower abdomen. Authors rule out the contamination from the skin and suggest two possible mechanisms of passage of barium from blood to cerebrospinal fluid (CSF) and so to the surface of the catheter.

Aged↗

Hepatocellular mitochondrial alterations in patients with chronic hepatitis C: ultrastructural and biochemical findings.

OBJECTIVE: Hepatitis C virus (HCV) infection is associated with increased lipoperoxidation, which may lead to interference with mitochondrial function with possible depletion of mitochondrial DNA (mtDNA). We correlated the ultrastructural findings of liver biopsy specimens with the lipoperoxidation markers and contents of mtDNA in chronic hepatitis C (CHC) patients with a different HCV genotype. METHODS: Liver biopsy samples obtained from 75 CHC patients were processed for histological and electron microscopic examination. Twenty-two subjects without known liver disease served as controls. Hepatic glutathione in its reduced (H-GSH) and oxidized (H-GSSG) forms were determined from biopsy specimens by high-performance liquid chromatography. Plasmatic and lymphocytic GSH and erythrocytic malonyldialdehyde (MDA) were also determined, along with the ratio between mtDNA and nuclear DNA (nDNA). RESULTS: Ultrastructural alterations of the mitochondria were documented in 23 patients with genotype 1b, compared with 15 patients with genotype 2a/2c (p = 0.020) and seven patients with genotype 3a (p < 0.001). A significant depletion of H-GSH and lymphocytic GSH, an increase of H-GSSG and MDA, and a reduction of the mtDNA/nDNA ratio were documented in patients with genotype 1b, compared with patients with genotype 2a/2c and 3a and with controls. CONCLUSIONS: In patients with genotype 1b frequent ultrastructural alterations of the mitochondria may be observed, and the depletion of mtDNA in these patients may represent the expression of a greater impairment of the process of oxidative phosphorylation. An increased production of free radicals in patients with genotype 1b may influence the evolution of the liver disease by enhancement of the cytopathic effect of HCV.

Adult↗

[Hormone replacement therapy and cardiovascular diseases: different populations, different risks].

Observational studies indicate that oral hormone replacement therapy (HRT) in menopause is associated with a 20-40% reduction of coronary risk. Population risk/benefit analyses on mortality after large-scale HRT use indicate that excess deaths can be counted when coronary heart disease is relatively less frequent than breast cancer before age 60 (as occurs in Italy). The decline in mortality trends for coronary heart disease support a word for caution for a large scale use of HRT in the next years even in those populations for which a relative advantage is presently estimated.

Cardiovascular Diseases↗

CG5/Dx human breast cancer cell line: characterization of a new doxorubicin-resistant variant.

By continuous exposure of CG5 human breast cancer cell line to increasing doxorubicin (Dx) concentrations, a multidrug-resistant (MDR) subline (CG5/Dx) was obtained. The resistant variant showed P-glycoprotein (P-gp) expression and a lower intracellular doxorubicin level than the parental cells. CG5/Dx cells were 19.4 fold more resistant to Dx than CG5 cells and showed a cross-resistance to some structurally related and unrelated compounds. Differences in kinetics, biological and ultrastructural features between the two cell lines were investigated. The CG5/Dx cells grew more slowly, produced higher CEA levels and showed a reduced progesterone receptor (PgR) content than the parental cells. Ultrastructural studies revealed differences involving, polyribosomes, rough endoplasmic reticulum, [mitochondria] and cytoskeleton.

ATP Binding Cassette Transporter, Subfamily B, Mem↗