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Biomedical subjects

F Riva

Publications and source records attributed to F Riva.

68 records · Page 4Linked to original sources
PubMedDate not supplied

Glucagon levels and ketogenesis in human diabetes following total or partial pancreatectomy and severe chronic pancreatitis.

In three groups of patients with insulin-dependent diabetes following total (n = 5) or partial (n = 5) pancreatectomy or chronic pancreatitis (n = 7) and in a group of idiopathic diabetics, ketogenic capacity following insulin withdrawal and during a 24-h fast was studied. Basal glucagon values were significantly increased in all diabetic groups with no significant intergroup differences. Basal ketone body values and their increase during starvation and insulin withdrawal were high and not different in totally pancreatectomized and primary diabetics, both showing unmeasurable C-peptide levels. On the contrary, ketogenesis was reduced in partially pancreatectomized and in pancreatitis diabetics with persistent levels of C-peptide. Our data confirmed the persistence of immunoreactive glucagon after pancreatectomy and demonstrated that ketogenesis is not suppressed in pancreatectomized diabetics and depends above all on residual B-cell function. A possible ketogenic effect of extra-pancreatic glucagon-like substances cannot be excluded.

Chronic Disease↗
PubMedDate not supplied

Prevalence of microangiopathic complications in hyperglycemia secondary to pancreatic disease.

Diabetes secondary to pancreatic disease (PD) represents a useful model for the study of the effects of chronic hyperglycemia on microangiopathic complications in the absence of those genetic factors predisposing to Type I diabetes. Our aim was to evaluate the prevalence of nephropathy and retinopathy in a group of 86 patients with PD. The genetic pattern, assessed by the determination of HLA antigens, was different than in patients with Type I diabetes. A family history of diabetes was present in 53% of the patients. The prevalence of retinopathy was 37%. Eighteen percent of the patients with duration of diabetes less than 10 years showed an albumin excretion rate (AER) greater than 40 mg/24 hr. The prevalence of pathologic microalbuminuria (greater than 40 mg/24 hr) was found in 29% of the patients with duration of diabetes greater than 10 years. The prevalence of pathologic microalbuminuria is related to the duration of diabetes. Both diastolic and systolic blood pressure is positively correlated to albumin excretion rate (p less than 0.02), suggesting a possible role of hypertension in the evolution of nephropathy. Sixty-one percent of the patients with AER greater than 40 mg/24 h had retinopathy, thus confirming the close association between renal and ocular complications. Abnormal microalbuminuria and retinopathy were not influenced by a family history of diabetes. We conclude that the prevalence of microangiopathic complications is similar to that seen in Type I diabetes, and the metabolic abnormalities of diabetes can play a direct role in the development of diabetic microangiopathy.

Albuminuria↗
PubMedDate not supplied

[Initial epidemiological data on the clinical effects in health workers employed in the manual lifting of patients in wards].

An investigation was carried out by teams from various centres coordinated by the EPM (Ergonomics of Posture and Movement) Research Unit on 54 different hospitals in various regions of northern and central Italy. The teams examined a total of 3341 health workers whose job involved manual handling of patients (553 male and 2788 females, 1568 working in hospitals and 1773 in geriatric residences). Numerous meetings were held to ensure that the methods of assessing the exposure indexes and spinal impairment were identical in the various teams. The final data were processed centrally at the EPM Research Unit. The sample analyzed may be considered as representative of the situation in hospitals in Italy, at least for northern and central Italy. The mean age was 36 years, mean length of service in the department 6 years and mean length of job duration not exceeding 10 years; staff turnover was high. Physical examination revealed that 8.4% of the workers had had at least one episode of acute low back pain in the previous 12 months: i.e., 4 times the values of the reference groups. Also in the case of clinical-functional spondyloarthropathies of the lumbosacral spine, in the females there was a significantly higher prevalence than in the reference groups. All disorders were more severe in sectors more at risk, i.e., old peoples homes, rehabilitation centres, orthopaedic and surgical departments, and in any case higher in old peoples homes and geriatric residences. The initial data concerning the ratio between presence of spinal disease and risk index were also positive.

Adult↗
PubMedDate not supplied

Effects of topoisomerase II inhibitors on gastric cancer cells characterized by different genetic lesions.

Gastric cancer is poorly-responsive to widely used antitumour drugs, the efficacy of which is thought to be related to the capacity of triggering apoptosis. This process requires a series of gene products including a functional p53 protein. We tested the effects of two DNA topoisomerase II poisons, etoposide and doxorubicin, on gastric cancer cell lines with different genetic lesions. We characterised MKN74 and MKN28 cells for p53 gene status and for the expression of p53 and p21 proteins, as well as of topoisomerase II alpha and beta isoforms. After drug treatments, the cells were analysed for drug cytotoxicity, colony forming ability, cell cycle distribution and presence of apoptotic features. Our findings demonstrated that both etoposide and doxorubicin have a potent anti-proliferative effect on gastric cancer cells. Cell death kinetics was different in the two cell lines, MKN74 cells being more sensitive than MKN28 to the drugs. MKN74 cells, although harboring a wt p53 gene, were unable to undergo a massive apoptosis following etoposide treatment. The response of this cell line might be related to the topoisomerase II beta isozyme, the expression of which proved to be undetectable.

Antibiotics, Antineoplastic↗
PubMedDate not supplied

Stimulation of osteoblast growth by an electromagnetic field in a model of bone-like construct.

The histogenesis of bone tissue is strongly influenced by physical forces, including magnetic fields. Recent advances in tissue engineering has permitted the generation of three dimensional bone-like constructs. We have investigated the effects of electromagnetic stimulation on human osteoblast cells grown in a hydrophobic polyurethane scaffold. Bone-like constructs were stimulated by pulsed electromagnetic fields in a bioreactor. Proliferation, bone protein expression and calcified matrix production by osteoblasts were measured using histochemical methods. In stimulated cultures, the number of cells was significantly higher compared to static (control) cultures. In both stimulated and control cultures, cells were immunoreactive to osteoblast markers, including type-I collagen, osteocalcin and osteopontin, thus suggesting that the expression of bone-related markers was maintained throughout the in vitro experiments. Morphometric analysis of von Kossa-stained sections revealed that stimulation with electromagnetic field significantly increased matrix calcification. The data lend support to the view that the application of a magnetic field can be used to stimulate cell growth in bone-like constructs in vitro. This finding may be of interest for the production of biomaterials designed for clinical applications.

Animals↗
PubMedDate not supplied

[A case-control study of multiple occupational risk factors in relation to laryngeal cancer].

In this work the A.A. present the results of a case-control study on 2,997 subjects carried out to evaluate the role of professional factors in the development of laryngeal cancer. Our analysis included only cases of laryngeal neoplasia at first diagnosis in 1990. From a statistical point of view we calculated the Odds Ratio (OR) and confidence limits at 95% following Miettinen. The analysis was made on 113 cases and 754 controls, all males smokers or ex-smokers, aged between 35-80 years. The results show a statistically significant correlation between laryngeal cancer and jobs in agriculture (OR = 3.77), in iron-steel industries (OR = 3.25), in metal-mechanic industries (OR = 1.72). Precise knowledge of such data could be very useful in promoting primary and secondary prevention campaigns in the above-mentioned work places. The A.A. stress the need to make experimental cancerogenesis studies to evaluate the effects of the association of occupational risk factors, tobacco smoke and alcohol consumption on the natural history of laryngeal cancer.

Adult↗
PubMedDate not supplied

3'-5' cAMP phosphodiesterase in pig liver nuclei.

cAMP phosphodiesterase was partially purified from pig liver nuclei and some of its properties were investigated. The enzyme is a low km PDE. Inhibition by xanthine derivatives is in line with the behaviour of PDE from other mammalian sources, while small differences are observed towards nucleotides inhibitors. The enzyme is a chromatin-bound protein although no specific location related to transcriptional function could be demonstrated.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMedDate not supplied

[Children with hemorrhagic diathesis: correct diagnostic and therapeutic approach].

Bleeding defects are of great interest in pediatrics since the prevalence of congenital forms and the early appearance of acquired ones. The pathology itself and the therapy indeed can often interfere with the growing-up patients. Bleeding defects have been identified with an heterogeneous group of clinical disease that differs from one another in etiology, pathogenesis, epidemiology and incidence in population. Bleeding diathesis is the common symptom: bleeding tendency may be mild, moderate or severe, localized or generalized, cutaneous or mucosal, superficial or deep. Bleeding disorders may be classified as a) defects in the primary haemostasis, which include quantitative and qualitative abnormalities of platelets and vascular disorders and b) defects in secondary haemostasis, which include intravascular disorders (blood coagulation). Careful history and clinical examination are essential in diagnosis of bleeding disorders. History of patient should be taken a) to differentiate acquired from congenital disease and to know the way of hereditary transmission (family history); b) to know exactly the disease's start and the mutual relation with former or accompanying disease; c) mutual relation with drugs token. Subsequently a careful physical examination should be done. A specific hemorrhagic diathesis has been seen with a deficiency of primary or secondary haemostasis. A deficient or late haemostatic plug in small vessels can cause superficial, interstitial bleeding that may be intracutaneous or intramucosal and is called purpura. In coagulation factor deficiency the haemostatic plug cannot be consolidated by fibrin: spontaneous hematomas, hemarthrosis and ecchymoses often occurs. The initial laboratory work up for screening patients with bleeding disorders should include first step tests to differentiate bleeding disorders for bone-marrow malignancies; from virus infections carrying screening of major viruses and from hepatic diseases. Second step laboratory examination includes a) platelet count or estimation of platelet number on blood smear; b) bleeding time to test small vessel integrity and platelet function; c) aPTT, PT, AP to measure clotting activity; d) fibrinogen determination. With this battery of screening test it is usually possible to determine the general area of the defect (abnormalities of platelets number or function or congenital defect of one or more clotting factors activity). Acute idiopathic thrombocytopenic purpura is the most common bleeding disorders in childhood. Usually no therapy may be required no matter platelet count. Patients with a significant hemorrhagic tendency are treated either with prednisone (2 mg/kg orally in divided daily doses) for a period of 2 weeks or with a 5 days course of special polyvalent intact immunoglobulin (400 mg/kg/die) for intravenous use.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMedDate not supplied

Inhibition of adenosine deaminase by deaza derivatives of adenosine and purine riboside.

Deaza analogs of adenosine, where carbon substitutes for nitrogen, are not substrates for adenosine deaminase (adenosine aminohydrolase EC 3.5.4.4); little is reported on their ability to be inhibitors. Among the deaza analogs of adenosine and purine riboside that we have been testing, 1-deazaadenosine proved to be the best inhibitor (Ki = 6.6 X 10(-7)M). 1-deazapurine riboside, 1,3-dedeazadenosine, 3-deazaadenosine have affinity by about two and three order of magnitude lower.

Adenosine Deaminase Inhibitors↗