Biomedical subjects

A Lentini

Publications and source records attributed to A Lentini.

At least 37 records · Page 2Linked to original sources

PubMed2000

Evaluation of the efficacy of potential antineoplastic drugs on tumour metastasis by a computer-assisted image analysis.

Computerised image analysis, performed on histological sections of (C57BL6/N) mouse lungs that had been intravenously (i.v.) injected with B16-F10 melanoma cells was used to develop a novel method to quantify the efficacy of potential antineoplastic drugs. This procedure allowed the evaluation of the rate of inhibition of growth and the anti-invasive capability of new molecules, thus resulting in more accurate data than that obtained from common macroscopical counting of surface metastatic foci. Several morphological parameters can be measured by this method: the percentage of tissue area occupied by metastases, which accounts for tumour implantation into the organ; the growth index, related to the size of the metastases, and the invasion index, related to the frequency of foci. These morphometric data were found to be correlated to the levels of lung hydroxyproline and transglutaminase activity, well known markers of tumour invasion and cell differentiation, respectively. The main objective of this computerised procedure was to evaluate how the tumour cell is affected in the host by the drug under investigation. The use of the method is exemplified by an analysis of the antitumour activity of some methylxanthines.

Animals↗

PubMed2000

Theophylline administration markedly reduces hepatic and pulmonary implantation of B16-F10 melanoma cells in mice.

Theophylline-treated B16-F10 melanoma cells show a lower experimental metastatic potential in vivo. To identify the possible mechanism(s) involved and on the basis of previous reports, we tested the induction of apoptosis in B16-F10 cells. Fluorescence activated cell sorter (FACS) analysis and p53 overexpression in theophylline-treated B16-F10 melanoma cells appeared to suggest enhanced cell death by apoptosis. The in vivo effects of orally administered theophylline in mice were investigated using different treatment schedules in mice that had undergone hepatic or pulmonary colonization with tumour cells. Mice received theophylline in their drinking water according to different protocols: (i) from 3 days before tumour cell inoculation until animal sacrifice ('early treatment'); (ii) from 3 days before until 3 days after tumour cell inoculation ('short treatment'); or (iii) from 3 days after tumour cell inoculation until animal sacrifice ('late treatment'). In the 'early treatment' group, the number of melanoma foci was reduced by 92.3% in the liver and 81.4% in the lung compared with control animals (P < 0.001). In the 'short treatment' group, there was an 80.2% and 72.2% reduction in liver and lung metastases, respectively (P < 0.001). In the 'late treatment' group, the inhibition of metastasis was 59.7% for liver and 45.3% for lung (P < 0.005). Survival studies showed that 50% of the 'early' theophylline-treated animals died 33.2 +/- 2.0 days after intrasplenic injection (control group: 23.1 1.8 days; P < 0.001) and 33.9 +/- 2.5 days after tail vein injection (control group: 24.1 +/- 1.4 days; P < 0.001). Taken together, these observations provide useful information for the potential clinical application of theophylline as a chemotherapeutic agent against malignant melanoma.

Animals↗

PubMed1999

Update on sequential isologous rat organ transplantation: pancreaticoduodenal and kidney transplantations.

This periodic report includes intermittent results of consecutive pancreaticoduodenal (Pd) and kidney (Kt) transplants in inbred rats and results on double kidney transplants that did not follow sequential transplant protocol. Eight 24-month-old Lewis pancreas, kidney, and aorta served histological controls showing normal histological architecture with no atherosclerosis developed in the aorta. Thirty-four month old pancreas and thirty-two month old kidneys, which resided in young hosts for at least three occasions, appeared as youthful Pd and Kt grafts. They show normal histological appearance for more than the expected life span of a Lewis rat. The fact that not only pancreases but also kidneys outlived their host leads to the study of other different organs' viability as aged valuable grafts. Nevertheless, the threats by the development of atherosclerosis in graft-associated aortas resulted in slow progression of the follow-ups.

Animals↗

PubMed1999

Why do women choose nursing?

To answer the question, "Why do women choose nursing?", female nursing students were given an opportunity to speak "in their own voices" to reveal their needs, motivations, and expectations. In a study employing grounded theory methodology, 16 female nursing students were interviewed and audiotaped for initial constant comparison analysis. Further analyses employing coding, categorizing, comparing, and contrasting of data made it possible to isolate recurrent words and phrases, and to identify concepts for the purpose of theory building. Reliability was established by both stability analysis and reproducibility analysis. Validity was supported by construct (convergent and discriminant) and representational components. Not surprisingly, the construct of desiring to care for others was readily apparent. However, it was power and empowerment that emerged from the interviews as the most resounding and fully developed construct of the study. Students' references to practical motivations for choosing nursing were so notably scarce that their virtual omission constituted an important theme.

Adolescent↗

PubMed1998

Tissue transglutaminase expression affects hypusine metabolism in BALB/c 3T3 cells.

Post-translational formation of hypusine in eukaryotic initiation factor 5A (eIF-5A) is essential for cell viability. Recently, we showed that hypusine protein is an in vitro substrate for transglutaminases (TGases). We report the effect of tissue TGase expression on the in vivo hypusine metabolic pathway. The stable expression of tTGase in BALB/c 3T3 cells induced a 100-fold reduction of hypusine levels and a 50% increase of gamma-glutamyl-omega-hypusine formation. Such changes were paralleled by a consistent decrease in the free polyamine pool and an enhancement of their excretion and of the formation of their gamma-glutamyl derivatives. These effects occurred together with a significant reduction of cell proliferation. In this report we suggest, for the first time, that tTGase affects hypusine metabolism, thus regulating the eIF-5A activity and cell proliferation.

3T3 Cells↗

PubMed1998

Inhibition of melanoma pulmonary metastasis by methylxanthines due to decreased invasion and proliferation.

Theophylline- and caffeine-treated B16-F10 cells exhibited low adhesion to laminin/collagen type IV and reduced invasion through Matrigel in an in vitro assay. In contrast, theobromine appeared ineffective. When young adult C57BL/6 mice were injected intravenously with theophylline-treated B16-F10 cells, the number of surface lung tumours was markedly reduced. Densitometric analyses performed on digitalized microscopic images of histological sections of lung were used to estimate the frequency (number of lung foci; NLF) and the size (average area of metastatic foci; AMF) of the resulting tumour foci. These parameters were correlated to the proliferation (AMF) and invasion (NLF) of melanoma cells in vivo. The data showed a similar theophylline-induced decrease in the AMF and NLF values (71%, P < 0.01). Caffeine treatment produced a more pronounced decrease in the AMF (61%, P < 0.01) than in the NLF (25%, P < 0.01). To our knowledge, this is the first demonstration that theophylline and caffeine possess the capacity to inhibit not only cell proliferation, but also the metastatic behaviour of melanoma cancer cells.

Animals↗

PubMed1997

[Reconstructive microsurgery].

Since Microsurgery was born, it has been employed in different surgical fields offering more recently good chances even 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 rate of success of surgical procedures. Therefore a close multidisciplinary relation between the different fields is absolutely required for a correct application of microsurgical techniques.

Female↗

PubMed1995

Phagocytosis of apoptotic bodies by liver endothelial cells.

Using electron microscopy and cytofluorimetry we studied the role of carbohydrate-specific recognition systems in the interaction of apoptotic bodies with normal and interleukin 1-activated sinusoidal endothelial cells. Microfluorimetric observation of liver tissue sections revealed octadecylrhodamine B-labelled apoptotic body binding to the sinusoidal wall of mouse liver, when they were injected intraportally. Plate-scanning cytofluorimetry demonstrated that about 20-25% of Acridine Orange-labelled apoptotic bodies could adhere specifically to cultured endothelial cells after 15 minutes of incubation. Adhesion increased to 30% when the cells were incubated for 60 minutes. Using a mixture of galactose/N-acetylglucosamine/mannose as competition solution apoptotic body adhesion was significantly reduced especially after longer times of incubation, when the percentage of inhibition reached 50%. Following 4 hours exposure of liver endothelial cells to 1 ng/ml human recombinant interleukin-1 beta adhesion markedly increased after 60 minutes of incubation, whereas the co-incubation of interleukin-1 beta with the inhibitors brings down the adhesion to basal values obtained in controls. Electron microscopic observation of the adhesion process showed that the number of endothelial cells binding apoptotic bodies gradually increased from low to high values with time. After 60 minutes of incubation, the majority of apoptotic bodies were seen inside phagosomes and only a few remained at the cell surface. Liver endothelial cells bound and endocytosed apoptotic bodies through carbohydrate-specific receptors. Moreover, this scavenger action was interleukin-1 enhanced, thus suggesting its possible activation during inflammatory and immune processes.

Animals↗

PubMed1995

Immunocytochemical study of binding and internalization of carrier-free Cu, Zn Superoxide dismutase by cultured rat hepatocytes.

Internalization of superoxide dismutase-gold complex by isolated liver cells has been shown to occur via receptor-mediated endocytosis. As colloidal gold may act as a carrier in this process, carrier-free human Cu, Zn superoxide dismutase was incubated with cultured rat hepatocytes. Light and electron microscopy immunocytochemistry revealed the binding and internalization of free native human Cu, Zn superoxide dismutase (hSOD) by cultured rat hepatocytes. Immunocytochemical demonstration of binding to the cell surface (hepatocytes were incubated with hSOD for 15 min. at 4 degrees C) and internalization (hepatocytes were incubated with hSOD for 15, 30 and 60 min. at 37 degrees C) of the carrier-free superoxide dismutase was achieved by using a monoclonal antibody selectively reacting with the human protein. The results obtained indicate that carrier-free superoxide dismutase is bound and internalized by rat hepatocytes in primary cultures and that the enzyme can enter the cells via a receptor-mediated endocytosis pathway. We followed the binding and the internalization process of hSOD thus validating the use of the native enzyme in the therapy of free radical-related diseases.

Animals↗

PubMed1994

Advances in rectal cancer surgery.

PURPOSE: We discuss our experience in radical rectal cancer surgery and critically review the results of the current literature. In particular, the importance of distal clearance, total excision of the mesorectum, and pelvic lymphadenectomy is stressed. METHODS AND RESULTS: The rationale for determining a pelvic lymphadenectomy is identified in the high percentage (20 percent) of lateral endopelvic metastatic nodes demonstrated in cases of extraperitoneal rectal cancers. The results after pelvic lymphadenectomy and the eventual complications are observed. The autonomic nerve-sparing procedure is described and the preliminary results, with a decreased rate of urinary and sexual sequelae, are discussed. CONCLUSIONS: It was concluded that, in cases of an advanced rectal cancer, radical surgery, if associated with the nerve-sparing technique, can improve survival without affecting the incidence of major complications.

Humans↗

PubMed1994

Interactions of hyaluronan (hyaluronic acid) with phospholipids as determined by gel permeation chromatography, multi-angle laser-light-scattering photometry and 1H-NMR spectroscopy.

The chain flexibility of solutions of hyaluronan (HA) of different molecular weights was determined by 1H-NMR spectroscopy in the absence and presence of the phospholipid dipalmitoyl-D,L-alpha-phosphatidylcholine (DPC). Sonication of high- or low-molecular-weight HA with DPC for periods of up to 120 min markedly increased HA chain flexibility as determined by observing the half-peak linewidths (delta V1/2) for the methyl protons of the acetamidodeoxyglucose residues of the HA molecules. Gel permeation chromatography of mixtures of purified high-molecular-weight HA (Healon) with 3H-DPC or 3H-platelet activating factor (PAF) showed exclusion of these radioactively labelled molecules from the gel in the presence of HA but not in its absence. Studies using multi-angle laser-light-scattering (MALLS) photometry of sonicates of DPC and Healon after Superose 6 chromatography revealed increases in HA Mw, Mn, Mz and their corresponding root mean square radii relative to control sonicates of HA without DPC. From these data, we have deduced that DPC binds to HA by competing for those hydrophobic centres along the HA chain which are normally responsible for the inter- and intra-chain interactions and which confer stiffness to the HA molecule. It is proposed that such interactions in arthritic joints could reduce synovial fluid viscoelasticity thereby diminishing the ability of this medium to protect articular cartilage from mechanical injury.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed1993

Modulation of the expression of galactose-specific receptors on Kupffer cells after partial hepatectomy and zymosan stimulation.

Partial hepatectomy (PH) and a single intravenous injection of zymosan were used to provoke expansion of the Kupffer cell population in rat liver. The number of Kupffer cells per unit of area of liver increased after both stimulations. During these growth phases the number of binding sites for galactose-exposing ligands was studied on Kupffer cell plasma membranes. Both partial hepatectomy and zymosan stimulation affected the binding of lactosylated bovine serum albumin conjugated to gold particles (LacBSA-Au5). The reduction observed depended on the time after the PH or zymosan injection studied. Low levels of binding sites were found at 24 h from PH and 5 days after zymosan stimulation and represented only 1/4 or 1/10 of the binding sites expressed on the cell surface of Kupffer cells from normal adult rats. In addition, in both experimental situations we observed that the clustered distribution of gold particles typical of adult Kupffer cell was changed.

Animals↗

PubMed1993

Galactose-specific receptor modulation related to the onset of apoptosis in rat liver.

The expression of the asialoglycoprotein receptor of hepatocytes and the galactose-specific receptors of non-parenchymal liver cells during the onset of apoptosis in liver of rats treated with lead nitrate was studied. During the involution of lead nitrate-induced hyperplasia in rat liver (occurring at 5 days after the injection) a significant increase of asialoglycoprotein receptor (ASGP-R) expression on hepatocytes coincided with the massive death by apoptosis of the same cells. The increase in the receptor expression was sustained by a large increase in the level of its specific mRNA. As a consequence of lead nitrate injection, we also detected a drastic change of the galactose-specific receptor expression and distribution on the surface of rat liver sinusoidal cells. However, the modulation of the receptor expression on the Kupffer cells did not parallel that observed for the ASGP-R: the peak of surface expression measured on hepatocytes always followed the one observed on Kupffer cells. Our data show a first evidence of a receptor modulation during the process of apoptosis. In fact, the entire carbohydrate recognition system of the liver is modulated during the onset of apoptosis induced by lead nitrate injection, but the pattern of modulation depends on the cellular types. We suggest that a physiological role for the hepatic carbohydrate recognition systems is related to the apoptosis of liver.

Animals↗

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↗