Biomedical subjects

D Bosco

Publications and source records attributed to D Bosco.

At least 37 records · Page 2Linked to original sources

PubMed2003

[Fractal analysis of liver fibrosis].

This study realized by two different study groups use of Fractal geometry to quantify the complex collagen deposition during chronic liver disease. Thirty standard needle liver biopsy specimens were obtained from patients with chronic HCV-related disease. Three mu-thick sections were cut and stained by means of Picrosirius stain, in order to visualise collagen matrix. The degree of fibrosis was measured using a quantitative scoring system based on the computer-assisted evaluation of the fractal dimension of the deposited collagen surface. The obtained results by both study groups, show that the proposed method is reproducible, rapid and inexpensive. The complex distribution of its collagenous components can be quantified using a single numerical score. This study demonstrated that it is possible to quantify the collagen's irregularity in an objective manner, and that the study of the fractal properties of the collagen shapes is likely to reveal more about its structure and the complex behaviour of its development.

Collagen↗

PubMed2002

Impact of integrin-matrix matching and inhibition of apoptosis on the survival of purified human beta-cells in vitro.

AIMS/HYPOTHESIS: Human islet cells survive poorly in culture and are overgrown by non-endocrine cells. The aims of this study were to sort human beta cells and to develop approaches for their improved survival in culture. METHODS: Human islets were infected with recombinant adenovirus expressing green fluorescent protein (GFP) under the control of the rat insulin promoter such that only beta cells expressed GFP. GFP-positive beta cells were sorted by flow cytometry, and expression of select integrins evaluated by RT-PCR. Beta cells were cultured on different extracellular matrices for up to 15 days. Apoptosis was measured by annexin V binding and ELISA. Insulin secretion was measured by ELISA. RESULTS: Sorted beta cells survived less well in culture than unsorted islet cells. This did not appear to be due to adenoviral infection and/or GFP expression. Purified beta cells expressed the integrins alpha 3, alpha 5, alpha 6, alpha V, beta1, but not beta 4. Of the various matrices tested, sorted beta cells attached and spread best on a lawn of lysed human bladder carcinoma cells (5637 cells). However, survival remained poor. Cell death was decreased but not prevented by continued presence of 10 mmol/l nicotinamide and apoptosis decreased by 24 h incubation with 20 micromol/l Z-VAD. Insulin secretion was maintained over 6 days following treatment with both agents. CONCLUSIONS/INTERPRETATION: Purification of human beta cells induces marked apoptosis limiting their function and survival in vitro. This was improved by matching the extracellular matrix to the specific expression of integrins and by addition of nicotinamide and Z-VAD.

Adult↗

PubMed2002

Body weight, levodopa pharmacokinetics and dyskinesia in Parkinson's disease.

We conducted a pharmacokinetic study in 164 patients with sporadic Parkinson's disease (PD) to address the relationship between body weight and levodopa pharmacokinetics. Patients underwent an oral acute levodopa test with 250 mg levodopa and pharmacokinetic variables were further assessed. Plasmatic levodopa area under the curve (AUC-l) and body weight were significantly and inversely correlated. Women were significantly lighter and more dyskinetic than men, and had greater AUC-l values. Our data suggest that during long-term treatment, lighter PD patients, especially women, may receive a greater cumulative dosage of levodopa per kilogram of body weight. This could explain gender differences for the development of levodopa-induced peak-dose dyskinesias observed during the course of the disease.

Administration, Oral↗

PubMed2002

Anti-GM1 ganglioside antibodies in Parkinson's disease.

OBJECTIVES: To determine whether anti-GM1 antibodies are increased in Parkinson's disease (PD). METHODS: Serum immunoglobulin M (IgM) and IgG anti-GM1 antibodies were detected by enzyme-linked immunosorbent assay (ELISA) in 147 patients with PD and in 186 age-matched normal control subjects. Sera were assayed at initial dilution of 1:800 for IgM and 1:200 for IgG and were considered positive at absorbance values exceeding the value of 0.05 for IgM and 0.1 for IgG. RESULTS: Forty patients with PD (27.2%) had sera positive for IgM anti-GM1 antibodies, whereas only five normal controls (2.7%) resulted positive (P < 0.0001). Most of patients (75%) with positive sera had a tremor-dominant form of PD. Only two patients with PD (1.4%) and none of normal controls had sera positive for IgG anti-GM1 antibodies. CONCLUSION: A consistent portion of parkinsonians, mainly with a tremor-dominant form of PD, may have increased circulating IgM anti-GM1 antibodies.

Aged↗

PubMed2002

NM23 expression as prognostic factor in colorectal carcinoma.

BACKGROUND: The current most important prognostic indicator in colorectal carcinoma is tumor stage at the moment of diagnosis. The role of NM23 gene as prognostic factor is controversial. The aim of this study was to investigate NM23 expression. PATIENTS AND METHODS: The study population included 104 unselected patients who underwent surgery for colorectal carcinoma between 1992 and 1997. NM23 expression was quantified by estimating the percentage of tumor cells with unequivocal reactivity. The percentage was scored: 0 when no tumor cells showed immunoreactivity; 1 when less than 10% of cells showed immunoreactivity; 2 when 11-50% of cells were positive; 3 when more than 51% of cells were positive. RESULTS: Four cases belonged to group 0.21 to group 1.55 to group 2 and 24 to group 3. CONCLUSION: NM23 cannot be considered an independent prognostic variable.

Antigens, Neoplasm↗

PubMed2001

The parkin gene is not involved in late-onset Parkinson's disease.

Mutations in the parkin gene have been reported in patients with early onset PD. The authors investigated the parkin gene in 118 patients who had an onset of PD after age 45 years: 95 subjects were sporadic patients and 23 subjects were from 18 families with a probable autosomal recessive inheritance. No pathogenetic mutations in the parkin gene were detected either in familial or in sporadic patients. Moreover, no differences were found between patients and 100 age-matched normal controls in the allele and genotype frequencies of four exonic parkin polymorphisms.

Age of Onset↗

PubMed2001

The parkin gene is not a major susceptibility locus for typical late-onset Parkinson's disease.

We investigated the parkin gene in 118 patients with typical Parkinson's disease (PD), i.e. in patients who had an onset of PD after the age of 45 years. The study group included 95 subjects with sporadic PD and 23 subjects from 18 families with autosomal recessive PD. No pathogenetic mutations in the parkin gene were detected either in familial or in sporadic patients. Our findings indicate that the parkin gene is not involved in the pathogenesis of classic late-onset PD.

Age of Onset↗

PubMed2001

Silent celiac disease in patients with childhood localization-related epilepsies.

PURPOSE: To evaluate how many patients with a clinical picture of idiopathic childhood localization-related epilepsies may also have silent celiac disease (CD). This will help determine whether investigation for CD should be restricted to those patients with childhood partial epilepsy with occipital paroxysms (CPEO) or should be extended to all patients with childhood partial epilepsy (CPE) regardless of seizure type and electroencephalographic (EEG) paroxysms. METHODS: The study group consisted of 72 patients (31 girls and 41 boys; mean age, 12.6 +/- 4.28 years; age at onset, 6.4 +/- 3.7 years) who were observed consecutively over a 5-year period and who received an initial diagnosis of idiopathic CPE. A diagnosis of CD was confirmed by using enzyme-linked immunosorbent assay (ELISA) to assess the presence of antigliadin antibodies and the immunofluorescent undirected test to assess the presence of antiendomysium antibodies. RESULTS: Twenty-five patients had CPEO, whereas the remaining 47 had CPE with centrotemporal spikes (CPEC). None of the patients with CPEC had positive antibody tests. Of the 25 patients with CPEO, two (8%) had antiendomysium immunoglobulin (Ig) A antibodies. In both of these patients, the jejunal biopsy showed atrophy of the villi and hyperplasia of the crypts, consistent with a diagnosis of CD. Brain computed tomography (CT) was normal in one of these patients and revealed occipital corticosubcortical calcifications in the other. CONCLUSIONS: Our study indicates that CD screening should be performed routinely only in patients with CPEO.

Age Factors↗

PubMed2001

Ultrastructural modifications and phosphatidylinositol-3-kinase expression and activity in myocardial tissue deriving from rats in different experimental conditions.

Oxygen supply is essential in the maintenance of the physiological cell metabolism. In fact, both lower and higher O2 concentrations induce modifications of the enzymatic activity of the cell which determine, in turn, morphological changes at nuclear and cytoplasmic level. Among the molecules involved in the maintenance of the cellular homeostasis, the signal transduction pathway PI-3-kinase/AKT-1 should be included. Here we suggest a relationship between the modulation of this pathway and the morphological modifications occurring "in vivo" in myocardial tissue upon hypoxic and hyperoxic stress. In particular, down regulation of this pathway, which when activated is known to deliver an anti-apoptotic signal, is concomitant to the maintenance of the apoptotic events occurring in these cells in response to oxidative stresses.

Animals↗

PubMed2001

Increased intracellular calcium is required for spreading of rat islet beta-cells on extracellular matrix.

Rat islet beta-cells spread in response to glucose when attached on the matrix produced by a rat bladder carcinoma cell line (804G). Furthermore, in a mixed population of cells, it has been observed previously that spread cells secrete more insulin acutely in response to glucose, compared with cells that remain rounded. These results suggest bi-directional signaling between the islet beta-cell and the extracellular matrix. In the present study, the role of increased intracellular free Ca2+ concentration [Ca2+]i as an intracellular step linking glucose stimulation and beta-cell spreading (inside-out signaling) was investigated. Purified rat beta-cells were attached to this matrix and incubated under various conditions known to affect [Ca2+]i. The effect of glucose on beta-cell spreading was mimicked by 25 mmol/l KCl (which induces calcium influx) and inhibited by diazoxide (which impairs depolarization and calcium entry) and by the L-type Ca2+ channel blocker SR-7037. When a 24-h incubation at 16.7 glucose was followed by 24 h at 2.8 mmol/l, beta-cells that had first spread regained a round phenotype. In the presence of thapsigargin, spreading progressed throughout the experiment, suggesting that capture of calcium by the endoplasmic reticulum is involved in the reversibility of spreading previously induced by glucose. Spreading was still observed in degranulated beta-cells and in botulinum neurotoxin E-expressing beta-cells when exocytosis was prevented. In summary, the results indicate that increased [Ca2+]i is required for the glucose-induced spreading of beta-cells on 804G matrix and that it is not a consequence of exocytotic processes that follow elevation of [Ca2+]i.

Animals↗

PubMed2001

[Genetics-based prognosis evaluation of patients surgically treated for sporadic colorectal cancer].

The basic assumption as rationale of this research was that DNA repair genes (MMR system) are at beginning of the genetic mutational cascade causing the induction of oncogenesis of sporadic colorectal cancers as well as their multiclonal heterogeneity. In a previous study the Authors randomly selected, from a series of 256 patients, 29 patients up to the age of 60 years who underwent surgery for colorectal carcinoma with radical intent. All selected cases were considered as sporadic cancers from a clinical point of view, since none of them fulfilled the Amsterdam criteria for HNPCC and familial adenomatous polyposis was included too. Mismatch repair gene proteins expression and, in particular, gene hMSH2 protein was investigated by immunohistochemistry analysis. In 12 cases (41.4%) hMSH2 exhibited strong expression in the tumoral cells as well as in the surrounding mucosa and at distant mucosa. In 14 cases (48.3%) loss of hMSH2 protein expression was observed in tumoral cells and low immunoreactivity was detected in peritumoral mucosa while strong hMSH2 expression was observed in distant mucosa. In a third small group of patients (10.3%) loss of hMSH2 protein expression was detected in tumoral, adjacent and at distance normal mucosa. After a five years follow up, 100% of twelve patients of first group are still alive vs 64.3% of fourteen patients of second group, while in the third group only one patient survives. These results support the hypothesis of an involvement of hMSH2 gene defect in development of a subset of sporadic colorectal cancer. For the patients with strong expression of hMSH2 in the tumoral cells as well as in the surrounding mucosa and at distant mucosa, this parameter could represent an independent criterion for a good prognostic value.

Colorectal Neoplasms↗

PubMed2000

The long-duration response to L-dopa in the treatment of early PD.

OBJECTIVE: To investigate the long-duration response (LDR) to L-dopa resulting from different regimens of L-dopa. BACKGROUND: In clinical practice, L-dopa is usually administered without considering the LDR due to the drug. Moreover, it has not been established whether in early PD a multiple daily intake of small doses of L-dopa may induce a sustained LDR. METHODS: Twenty-four patients with early PD underwent a double-blind, crossover trial, comparing three different 15-day treatment periods with L-dopa: treatment A (250 mg every 24 hours); treatment B (250 mg every 8 hours); and treatment C (125 mg every 8 hours). After completion, 20 patients underwent a subsequent open-label randomized trial with prolonged treatments (250 mg every 24 hours or 125 mg every 8 hours) up to 3 months. LDR was measured at the end of each treatment. RESULTS: All patients achieved a sustained LDR after treatments A and B, whereas only 17% of patients reached a sustained LDR after treatment C. Overall, the LDRs resulting from treatments A and B had similar magnitude and were larger than the LDR deriving from treatment C. After 3 months of prolonged treatments, only three of 10 patients treated with 125 mg every 8 hours increased their LDR, whereas all 10 patients treated with 250 mg every 24 hours had a maximal and stable LDR. CONCLUSIONS: Sustained LDR to L-dopa is dependent on the amount of the single doses of the drug. A regimen scheduling small, divided doses during the day, as done in clinical practice, is a questionable therapy for the achievement of a sustained LDR.

Aged↗

PubMed2000

Glucokinase and glucokinase regulatory protein: mutual dependence for nuclear localization.

Conditional expression of the glucokinase regulatory protein in insulinoma cells, under control of the reverse tetracycline-dependent transactivator, was used to investigate whether expression of this protein de novo would alter the intracellular distribution of glucokinase. The regulatory protein, which was undetectable in the basal state, could be induced by doxycycline to levels comparable to those of liver and was detected mostly in the nucleus. Concomitantly, glucokinase accumulated in the nucleus. Human embryonic kidney cells were transiently transfected to express glucokinase and the regulatory protein, either separately or together. Each protein localized predominantly to the cytoplasm when expressed alone. On co-expression, however, both proteins localized virtually entirely to the nucleus. The enzymic activity of glucokinase was not required for promoting nuclear import of the two proteins, as shown with a glucose-phosphorylation-deficient mutant. Finally, in embryonic kidney cells expressing the regulatory protein alone, treatment with leptomycin B resulted in a partial redistribution of the protein from the cytoplasm to the nucleus, suggesting that this protein can shuttle between the two compartments.

Adaptor Proteins, Signal Transducing↗

PubMed2000

Lupus anticoagulant positivity in insulin dependent diabetic patients: an additional risk factor in the pathogenesis of diabetic retinopathy?

AIMS: To investigate whether lupus anticoagulant (LA) positivity, a marker of endothelial dysfunction, might be relevant to the pathogenesis of diabetic retinopathy (DR). METHODS: 32 IDDM patients were examined for LA, fibrinogen, prothrombin (PT), PTT, prothrombin degradation products (F1+2), and activated protein C (APC). RESULTS: APC decreased and F1+2 increased significantly in LA positive but not in LA negative patients; 60% of LA positive and 18% of LA negative subjects had DR. PT, PTT, and fibrinogen levels were insignificant. CONCLUSION: These preliminary findings suggest that LA positivity could represent an additional risk factor for DR, acting as a link between the immunological and haemostatic systems.

Adult↗

PubMed2000

Junctional communication of pancreatic beta cells contributes to the control of insulin secretion and glucose tolerance.

Proper insulin secretion requires the coordinated functioning of the numerous beta cells that form pancreatic islets. This coordination depends on a network of communication mechanisms whereby beta cells interact with extracellular signals and adjacent cells via connexin channels. To assess whether connexin-dependent communication plays a role in vivo, we have developed transgenic mice in which connexin 32 (Cx32), one of the vertebrate connexins found in the pancreas, is expressed in beta cells. We show that the altered beta-cell coupling that results from this expression causes reduced insulin secretion in response to physiologically relevant concentrations of glucose and abnormal tolerance to the sugar. These alterations were observed in spite of normal numbers of islets, increased insulin content, and preserved secretory response to glucose by individual beta cells. Moreover, glucose-stimulated islets showed improved electrical synchronization of these cells and increased cytosolic levels of Ca(2+). The results show that connexins contribute to the control of beta cells in vivo and that their excess is detrimental for insulin secretion.

Animals↗

PubMed2000

Importance of cell-matrix interactions in rat islet beta-cell secretion in vitro: role of alpha6beta1 integrin.

It has long been recognized that islet cell function is rapidly altered in vitro, but can be maintained, at least in part, when cells are layered on defined extracellular matrices. The present work addresses the influence of short-term cell-matrix interactions on islet beta-cell function and provides first insight into the molecular basis of these interactions. When primary rat beta-cells were allowed to attach to a matrix produced by a rat carcinoma cell line (804G), there was an increased insulin secretory response to secretagogues. This change was the result of an increase in the proportion of actively secreting beta-cells and in the amount of insulin secreted per active cell, as shown using the reverse hemolytic plaque assay. In turn, the spreading or flattening of beta-cells on this matrix was enhanced by secretagogues, and flattened cells secreted more insulin than rounded cells. Using indirect immunofluorescence, it was found that 1)alpha6beta1 integrins are present at the surface of islet cells in situ, 2) alpha6beta1 expression is heterogeneous among purified beta-cells and is upregulated by insulin secretagogues, 3) alpha6beta1 expression is higher in spreading cells, and 4) anti-alpha6beta1-specific antibodies decrease spreading. These observations demonstrate that islet cell-matrix interactions can improve the sensitivity of insulin cells to glucose and are mediated, at least in part, by alpha6beta1 integrins, suggesting that outside-in signaling through alpha6beta1 integrin plays a major role in the regulation of beta-cell function.

1-Methyl-3-isobutylxanthine↗

PubMed2000

Benign tumors of heterotopic tissue in the thyroid gland: a report of two cases of lipomatous lesions.

A report of two cases, concerning heterotopic nests of fat cells in the thyroid gland, is presented here together with a review of lipomatous lesions in the literature. Both cases involved patients who presented with goiter; one had Grave's disease and the other had adenomatous hyperplasia. The fat cells were principally located in the subcapsular areas and scattered among the follicles. The distribution of the immunohistochemical staining, and the morphologic characteristics of the adipose tissue, suggested a probable origin of the fat cells from inclusion nests during embryogenesis of the thyroid gland.

Adipocytes↗

PubMed2000

[Secondary costal myxoid chondrosarcoma. Presentation of a clinical case].

A type of malignant neoplasm of not frequent observation is reported and the difficulties concerning the distinction from the benign counterpart are underlined, for which a detailed instrumental study is made necessary, integrated with pre and, above all, postoperative histologic analysis. A white male patient of 83, affected by plurirecidivant chondromyxoma of the rib, was admitted for local recurrence. The lesion objectively appeared not dissimilar from the preceding ones, as an ovalar mass fixed on the underlying plains. Radiologic and ultrasonographic examinations seemed to confirm the admission diagnosis; at the end the patient underwent a new intervention. Histologic examination of the lesion yielded a diagnosis of chondromyxosarcoma. The clinical case is made even more interesting by the finding, through the TC technique, preoperatively performed, of a metastatic repetition on the opposite side. The authors examine the problem of the early recognition of a malignant neoplasm developing, in a patient with a clinical history of recidival chondromyxoma. Physical examination and laboratory analysis are not useful in the assessment of the occurring transformation. At molecular level chondromyxosarcoma is characterized by several genomic rearrangements and mutations. Though primitive chondromyxosarcoma often involves the ribs, chondromyxoma's transformation into its malignant counterpart is not a common event. The development of distant metastasis characterizes long term cases. Given the lack of encouraging results about chemo and radio-therapy efficacy in influencing the natural course of the disease, a systematic approach will be made necessary in patient management.

Aged↗