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Biomedical subjects

A Lentini

Publications and source records attributed to A Lentini.

16 recordsLinked to original sources
PubMed1992

The clearance of apoptotic cells in the liver is mediated by the asialoglycoprotein receptor.

Apoptosing cells are actively phagocytosed in parenchymal tissues, thus preventing the inflammatory reaction which could derive from their slow uncontrolled degradation. The molecular mechanisms by which an apoptotic cell is recognized and taken up are largely unknown. We propose that the recognition of apoptotic hepatocytes is mediated by the sugar recognition systems of the liver, particularly the asialoglycoprotein receptor (ASGP-R). The results presented here demonstrated the participation of ASGP-R in the removal of apoptotic parenchymal cells, and indicate a new perspective for the understanding of its physiological role.

Acetylgalactosamine↗
PubMed1992

The simultaneous exposition of galactose and mannose-specific receptors on rat liver macrophages is developmentally regulated.

We studied the simultaneous binding of galactose and mannose-exposing ligands in sinusoidal rat liver cells during development and aging. The galactose-specific receptors were visualized using 17 nm diameter colloidal gold particles coupled with Lactosylated bovine serum albumine (LacBSA), while mannose-specific receptors were localized by means of 5 nm diameter particles adsorbed with mannan. We observed the presence of four different classes of Kupffer cells in relation to the ligands bound. The percentage of each group of Kupffer cells varied in relation to the age of the subject from which the sample was taken. There were few double-labelled cells in the livers from newborn rats, with numbers increasing with age to adulthood, and decreasing again in the older animals. Cells without labelling were in the majority after birth, but they decreased in number up to adulthood and increased again during subsequent aging. The numbers of single-labelled cells did not change significantly during liver maturation. We hypothesize that the exposition of galactose and mannose-specific receptorial systems is regulated by developmental conditions.

Aging↗
PubMed1992

Receptor-mediated endocytosis of galactose and mannose exposing ligands: an electron microscopic study on adult and neonatal cultured rat hepatocytes.

We compared the receptor-mediated endocytosis for galactose and mannose exposing ligands in primary cultures of hepatocytes from newborn and adult rats. The endocytic pathway was revealed ultrastructurally using colloidal gold particles coupled to lactosylated bovine serum albumin and invertase. The binding activity on the cell surfaces is observed by keeping the cells at 4 degrees C. For both ligands used, the binding capacity for hepatocytes from adult rats was greater than for neonatal cultured cells. Increasing the temperature to 37 degrees C, we observed that the protein-gold complexes entered the intracellular endocytic organelles. Within 5-15 min, the marker was confined in vesicles close to the cell surface and in the endosome, while after 60 min, the marker is found in lysosome-like compartments. We found that the process of endocytosis is similar for galactose and mannose exposing ligands. The organelles involved in the process of endocytosis in newborn cultured hepatocytes are not different in shape from those of cultured cells of adult rats, but the process of internalization is slower.

Aging↗
PubMed1992

[Thyroid gland stimulation test in Reinke's edema. A study of 28 patients].

In order to clarify the correlation between Reinke's oedema and thyreopathies, we performed a study on 28 patients affected by polypoid degeneration of the vocal cords. Every patient had a complete check-up concerning the otorhino-laryngological either endocrinological aspects, in particular blood laboratory tests including the routine ones and RIA for T3, T4, FT3, FT4, hGT, antibodies and TSH under stimulation of the TRH. 22 patients showed to be affected by subclinical hypothyroidism; 5 patients did not show a substantial increase of the TSH to the TRH stimulation; one patient was affected by hypothyroidism. Our experience clearly shows that subclinical hypothyroidism is the organic pathology more frequently correlated with Reinke's oedema.

Adult↗
PubMed1992

[The Soupault-Bucaillle operation in the treatment of Billroth II gastric resection syndrome].

The study analyzes the benefits related to the gastroduodenojejunoplasty (GDJP) according to Soupault & Bucaille, adopted as the corrective treatment of the Billroth II gastric resection syndrome in those cases resistant to the dieting-pharmacological supports. Our experience is based on 18 cases (13 males, 5 females, mean age 39 yrs), treated from 1982 to 1987 with GDJP for a gastric resection syndrome. The patients were observed 5 years after their resection: 10 presented with an atrophic gastritis/gastric atrophy and all had a diffuse acute phlogosis in presence of biliary storage. Manual anastomoses were performed in the first 8 cases, while staplers were used in the remaining cases. Results were quite satisfying; no operative mortality or specific complications, nor pain and biliary vomiting were registered; 14 patients over 18 (77%) gained weight significantly; only 1 patient reported low-intense early "dumping-like" symptoms easily controlled by medical therapy. Endoscopy showed no biliary reflux in all cases. Biopsies of the stump, carried on before and after the GDJP intervention, showed a marked reduction of the inflammatory aspects in 76% (13) of the patients. Among the 10 patients with atrophic gastritis/gastric atrophy, only 2 (20%) presented a significant increase in the number of gastric parietal cells and gastric principal cells.

Adult↗
PubMed1991

[Anastomosis or closure of the pancreatic stump after duodenopancreatectomy?].

From 1986 to June 1990, 10 pancreaticoduodenectomies were performed in our Department (VIII Patologia Chirurgica, Università "La Sapienza", Roma). The reconstructive sequence was based on the pancreaticojejunal anastomosis (2 end-to-end pancreaticojejunostomies after invagination, 3 end-to-side Wirsung jejunostomies) in 5 patients. The pancreatic stump was sutured using a 50mm linear stapler in the remaining 5 patients. There was a high incidence (75%) of fistulization after direct suture of the pancreatic stump, although related mortality was null. Among patients treated with pancreaticojejunal anastomosis, a fistula on the end-to-end pancreaticojejunostomy with exitus of the patient, was registered in 1 case. On principle, we believe a end-to-side Wirsung jejunostomy should be performed after pancreaticoduodenectomy. When a safe anastomosis of the pancreatic stump cannot be performed (because of the soft parenchyma, easily lacerable) the technique of the direct suture with stapler is advisable.

Adenocarcinoma↗
PubMed1991

[Reconstructive microsurgery].

Progress in microsurgery has been accomplished by the technical improvements of the operative microscope and other delicate surgical instruments. Therefore, even small arteries as well as female tuba and male deferens, either presenting mechanical obstruction or a section, can be reconstructed. The same procedure may be applied in case of nerve injuries. Since Microsurgery was born, it has been employed in different medical fields offering lately good chances in sterility. Furthermore, microsurgical techniques offer a great support to Plastic Surgery. In fact, it is possible to repair wide tissue damages of the skin, muscles or bones using free flaps. The percentage of success of this Surgery increased the overall percentage obtained in General Surgery. Therefore a close multidisciplinary relation between the different Medical fields is absolutely required for a correct application of microsurgical techniques.

Adolescent↗
PubMed1990

Binding and uptake of ligands for mannose-specific receptors in liver cells: an electron microscopic study during development and aging in rat.

The binding and uptake of mannose exposing ligands in rat liver cells during development and aging was studied. The mannose-specific receptors are visualized using 5-nm diameter colloidal gold particles coated with invertase or mannan. It was found that the binding sites are present on sinusoidal liver cells since prenatal life but their quantitative and qualitative cell surface expression changes with age. The number of receptors affects the endocytotic capacity of Kupffer cells which is low during perinatal and aging periods and reaches the values of adult animals between the 11th and the 15th day after birth. Our results indicate that the expression and the activity of mannose-specific receptors on sinusoidal rat liver cells is related to the differentiative stage of the organ.

Aging↗
PubMed1987

Synthetic inhibitors of human leukocyte elastase, Part 3. Peptides with alkyl groups at the N- or C-terminus. Non-toxic competitive inhibitors of human leukocyte elastase.

A series of carboxy-alkylamidated and N-acetylated amino acids and peptides were synthesized and examined for their ability to inhibit human leukocyte elastase. The Boc-amino acid alkylamides were found to be potent specific and competitive inhibitors of this enzyme. They were found not to or only poorly inhibit several other serine proteinases such as bovine trypsin, alpha-chymotrypsin, porcine pancreatic elastase and human leukocyte cathepsin G at concentrations less than 10(-4) M. Specificity and maximum inhibition of human leukocyte elastase were achieved when the N-terminus of the amino acid was protected by a t-butyloxy-carbonyl (Boc) group, the oligopeptide fragment consisted of valine residues and when the alkyl chain was between 10 and 12 carbon atoms in length and attached to the C-terminus of the peptide fragment. Highest inhibition was obtained with the compound Boc-[Val]3-NH[CH2]11--CH3 (Ki = 0.21 microM). These specific inhibitors were also found to be non-toxic after oral administration to mice and rats (LD50 greater than 3.0 g/kg body weight).

Amino Acids↗
PubMed1987

Synthetic inhibitors of human granulocyte elastase, Part 4. Inhibition of human granulocyte elastase and cathepsin G by non-steroidal anti-inflammatory drugs (NSAID)s.

A series of non-steroidal anti-inflammatory drugs (NSAIDs) and some of their metabolites were evaluated for their ability to inhibit the proteolytic activity of human granulocyte elastase (HGE) and cathepsin G (HGC-G). The enzyme activity was monitored using specific synthetic chromogenic substrates. The results obtained indicated that phenylbutazone, sulindac, piroxicam and gold sodium thiomalate significantly inhibited HGE (Ki less than 0.5 mM), while only sulindac, diflunisal and gold sodium thiomalate were effective inhibitors of HGC-G (Ki less than 0.4 mM). Studies on metabolites of some of the NSAID tested were found to be superior inhibitors of both HGE and HGC-G than the parent molecules. Moreover, of the 18 compounds examined, the major metabolite of sulindac, sulindac sulphide was the most potent inhibitor of HGE (Ki = 0.01 mM) and HGC-G (Ki = 0.15 mM).

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1985

Synthetic inhibitors of human leukocyte elastase Part 1--Sulphated polysaccharides.

Ten dextran sulphates and six chitosan sulphates of variable Mr and extent of sulphate substitution have been examined for their ability to inhibit human leukocyte elastase (HLE). All were potent partial non-competitive inhibitors of this enzyme, highest activity being obtained with compounds of large molecular weight and maximum sulphate incorporation (Ki = 5.0 X 10(-10)M]. In all cases, the dextran sulphates were more effective inhibitors than chitosan sulphates of similar size and charge, but both classes were inactive against bovine trypsin, chymotrypsin and porcine pancreatic elastase at concentrations less than 10(-4)M. The data suggest that drug binding to HLE occurs by stereospecific electrostatic interactions at site(s) removed from the catalytic reaction centre.

Chitin↗
PubMedDate not supplied

Receptor mediated endocytosis of N-acetylglucosamine and mannose exposing molecules by cultured chick embryo hepatocytes.

We studied the receptor mediated endocytosis of a modified glycoprotein (N-acetylglucosamine-BSA) and mannan in cultured hepatocytes isolated from 19-days-old embryos. The binding sites for molecules exposing terminal N-acetylglucosamine (GlcNac) and mannose residues were localized and quantified at the ultrastructural level by means of protein-gold complexes. The binding sites were found to be randomly distributed as single gold particles on cultured hepatocyte cell surfaces not restricted to specialized areas of the plasma membrane. The gold ligands were internalized following a receptor mediated pathway, which was studied at different interval times (15, 30 and 60 min.) after incubating the cells with the electron dense markers.

Acetylglucosamine↗