Biomedical subjects
Publications and source records attributed to G D'Amico.
Following a discussion of the various methods of colorectal anastomosis in cancer surgery, the Authors describe a technical variant using a mechanical stapler in a high rectal location. The rapidity of anastomosis as well as the decreased risk of dehiscence, fistula and stenosis are underlined.
OBJECTIVE: To assess the effectiveness of beta-blockers and endoscopic sclerotherapy in the prevention of first bleeding and reduction of mortality in patients with cirrhosis and esophagogastric varices. DATA SOURCES: Pertinent studies were selected using MEDLINE (1980 to 1990), reference lists from published articles or reviews, and congress abstract lists. STUDY SELECTION: Randomized trials comparing beta-blockers or sclerotherapy with a nonactive treatment. Nine randomized clinical trials of beta-blockers and 19 trials of sclerotherapy were reviewed. Seven trials of beta-blockers and 15 of sclerotherapy were published as full papers. DATA EXTRACTION: Crude rates of bleeding and death in treated and control groups were extracted from each trial by three independent observers according to the intention-to-treat principle. The quality of published papers was systematically assessed and scored. DATA SYNTHESIS: The Mantel-Haenszel-Peto method was used for statistical evaluation of heterogeneity and for pooling of the results. No substantial heterogeneity was found, and the incidence of bleeding in trials of beta-blockers was significantly reduced (pooled odds ratio, 0.54; 95% CI, 0.39 to 0.74), particularly in patients with large or medium-sized varices or in those with varices and a hepatic vein pressure gradient above 12 mm Hg; however, only a trend toward reduced mortality was obtained. Sclerotherapy trials were highly heterogeneous in the direction of the treatment effects on both bleeding (pooled odds ratio, 0.6; CI, 0.49 to 0.74) and mortality (pooled odds ratio, 0.76; CI, 0.61 to 0.94). The quality of the trials and the rate of bleeding in the untreated groups were the major sources of heterogeneity. The favorable results of sclerotherapy were obtained in trials with high bleeding rates among controls; several of these trials had a low quality score. CONCLUSIONS: Beta-blockers may be recommended for prevention of first bleeding in cirrhotic patients with varices who have a high risk for bleeding. The effectiveness of sclerotherapy remains undetermined. Further trials in high-risk patients may prove useful if improved criteria to predict bleeding risk become available.
Nephrotic patients with persistent proteinuria also have various lipid abnormalities that may promote atherosclerosis and more rapid progression of renal disease. We aimed to find out whether dietary manipulation can correct the hyperlipidaemia found in these patients. After a baseline control period of 8 weeks on their usual diets, 20 untreated patients with chronic glomerular diseases, stable long-lasting severe proteinuria (5.9 [SD 3.4] g/24 h) and hyperlipidaemia (mean serum cholesterol 8.69 [3.34] mmol/l) ate a vegetarian soy diet for 8 weeks. The diet was low in fat (28% of total calories) and protein (0.71 [0.36] g/kg ideal body weight daily), cholesterol free, and rich in monounsaturated and polyunsaturated fatty acids (polyunsaturated/saturated ratio 2.5) and in fibre (40 g/day). After the diet period the patients resumed their usual diets for 8 weeks (washout period). During the soy-diet period there were significant falls in serum cholesterol (total, low-density lipoprotein, and high-density lipoprotein) and apolipoproteins A and B, but serum triglyceride concentrations did not change. Urinary protein excretion fell significantly. The concentrations of all lipid fractions and the amount of proteinuria tended to return towards baseline values during the washout period. We do not know whether the favourable effect of this dietary manipulation on proteinuria was due to the qualitative or quantitative modifications of dietary protein intake or was a direct consequence of the manipulation of dietary lipid intake.
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The most recent studies, using the actuarial life-table technique, of the problem of long-term renal outcome and the factors that influence it in adult patients with one of the three most common types of chronic idiopathic immune complexes-mediated glomerulonephritis (IgA nephropathy [IgAN], membranous nephropathy [MN], and type I membranoproliferative glomerulonephritis [MPGN]) are reviewed. In the last decade, renal survival 10 years after onset has become similar to adult patients with idiopathic IgAN (80% to 87%) and idiopathic MN (75% to 83%), because of improvement of the renal survival of patients with MN. Renal survival at 10 years is worse for adult patients with idiopathic type I MPGN (60% to 64%). There is no substantial difference in the average renal survival times between different geographical regions, with the exception of a better prognosis for idiopathic MN in Japan. The presenting clinical factors that most strongly predict subsequent poor outcome are similar for the three types of glomerulonephritis and are rather nonspecific: (1) severe proteinuria, (2) impairment of renal function, and (3) arterial hypertension. As for the histological features, the most powerful predictor of subsequent progression in all three types of glomerulonephritis is tubulointerstitial damage, suggesting that a cell-mediated immune process believed to occur there may independently influence outcome in glomerular diseases.
Many features suggest that a genetically mediated abnormality of the IgA immune response is central in the pathogenesis of IgA nephropathy (IgAN). Candidate disease susceptibility genes include those encoding the MHC class II antigens, HLA-DR, -DQ, and -DP, and we have recently described an HLA-DQB1 association in IgAN. Polymorphisms of the HLA-DP region loci have been shown to associate with autoimmune diseases which share immunological features with IgAN; coeliac disease (CD) and dermatitis herpetiformis (DH). We have therefore examined restriction fragment length polymorphisms (RFLPs) of the DP alpha and DP beta chain genes (DPA1 and DPB1 respectively) in IgAN, and have studied three caucasoid populations (North, Mid, Southern Europe) to determine whether ethnic variation in genetic susceptibility exists. DNA was extracted from blood (IgAN, UK n = 89, Italy n = 75, Finland n = 49; Controls, UK n = 99, Italy n = 54, Finland n = 45), and studied by Southern blot hybridization techniques using the restriction enzymes BgI II and Msp I and cDNA 32P-labelled DPA1 and DPB1 probes respectively. The frequency distribution of the DPA1 and DPB1 fragments was similar between the three caucasoid IgAN patient groups compared to their respective controls. There was no association of DPA1 or DPB1 RFLPs with clinical features. These results suggest that HLA-DP region genes are not important in conferring disease susceptibility to IgAN and do not influence clinical disease expression. Moreover, different immunogenetic mechanisms operate in IgAN, CD, and DH.
We updated meta-analysis and critical descriptive analysis of randomized clinical trials (RCTs) assessing the value of beta-blockers in preventing first bleeding (prophylactic) or rebleeding (therapeutic) and on survival of patients with cirrhosis. Both the methods of Peto-Mantel-Haenszel and DerSimonian-Laird were used to assess the heterogeneity and obtain cumulative estimates of treatment effects; the L'Abbé plot was also used for a visual assessment of heterogeneity in the direction of treatment effect. Seven prophylactic and nine therapeutic RCTs were analysed. beta-Blockers uniformly reduced the bleeding risk and revealed a trend toward improved survival in non-ascitic, well-compensated patients in both the prophylactic and therapeutic sets of RCTs. Discordant results were found in patients with ascites or in poor functional condition.
In an uncontrolled trial, patients with IgA nephropathy (IgAN) were treated with drugs that can alter the intestinal mucosal permeability to food antigens. These drugs are known to ameliorate urinary abnormalities and histological lesions of IgAN associated with ulcerative colitis or Crohn's disease [5-aminosalicylic acid (5-ASA)] or to prevent, in mice, the induction of IgAN-like disease by oral immunization [disodium cromoglycate (SCG)]. Nine patients [serum creatinine (s-Cr) less than 2 mg/dl; 24-hour proteinuria higher than 1.5 g, but not nephrotic) were treated with 5-ASA (2.4 g/day for 6 months); 9 similar patients were treated with SCG (400 mg/day for 6 months); the follow-up extended to 6 months after stopping therapy. The 5-ASA group showed a slight but not significant decrease in s-Cr, 24-hour/proteinuria, IgA circulating immune complexes (IgA-CIC) and IgA rheumatoid factor (IgA-RF); serum beta 2-microglobulin and serum IgA were unchanged; 2 of 9 treated patients showed, after 6 months of therapy, a reduction in proteinuria of more than 50% that lasted for the subsequent 18 months. The SCG-treated group showed a slight but not significant increase in 24-hour proteinuria and a significant decrease in serum IgA; unchanged were s-Cr, IgA-CIC, IgA-RF, serum beta 2-microglobulin; no patient treated with SCG showed a reduction in proteinuria of more than 50%. At the dosages and for the periods used, 5-ASA and SCG did not show a significant influence on clinical and laboratory parameters of disease in IgAN; other trials with increased dosages are warranted to definitely ascertain the possible therapeutic role of these drugs in IgAN.
Cefixime, a new orally absorbed iminomethoxyaminothiazolyl cephalosporin, was tested against some microorganisms involved in upper and lower respiratory tract infections such as Haemophilus (influenzae and parainfluenzae), Moraxella catarrhalis and Streptococcus pneumoniae, isolated in the period from November 1990 to April 1991. Its activity was compared to nine other antimicrobial agents: erythromycin, trimethoprim-sulfamethoxazole, ampicillin, amoxicillin-clavulanate, cefaclor, ceftazidime, ceftriaxone, cefotaxime and ofloxacin. Cefixime inhibits 90% of S. pneumoniae, H. influenzae and H. parainfluenzae, both beta-lactamase producers (BLP) or not (NBLP) at concentrations of less than 0.25 mg/l. It inhibits 90% of M. catarrhalis (BLP and NBLP) at concentrations of less than 1 mg/l. In general, cefixime has a superior in vitro activity with respect to cefaclor and the other cephalosporins as well as erythromycin and amoxicillin (the last one in BLP strains). In the evaluation of the antibacterial activity of beta-lactam against Haemophilus and M. catarrhalis, the authors observed different indications in the guidelines for ampicillin. Cefixime is not destroyed by the plasmid-mediated beta-lactamase produced by Haemophilus sp. and M. catarrhalis (TEM and ROB in Haemophilus strains and BRO in M. catarrhalis). In view of its excellent in vitro activity against the commonly encountered respiratory tract pathogens, cefixime is indicated in the therapy of these infections.
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The clinical and histological features of idiopathic mesangiocapillary glomerulonephritis (MCGN) have been reviewed, with a survey of the most recent literature, including the retrospective analysis of the data of the Italian Study Group of Renal Immunopathology on 368 patients. In both major types of MCGN, six morphological variants have been characterized (classical MCGN, nodular MCGN, exudative MCGN, focal segmental MCGN, MCGN with massive deposits, and crescentic MCGN) that have different etiologic, pathogenetic, or clinical outcome correlates. Actuarial renal survival 10 yr after renal biopsy has been calculated with life-table analysis to be 60 to 65% in type I MCGN, without significant differences between treated and untreated patients; none of the therapeutic regimens tested up to now for this disease have been independently demonstrated to be efficacious. As for the pathogenesis, the interrelationships between the three mechanisms that contribute to the development of the morphological features of the disease (accumulation of electron-dense deposits on the subendothelial side of the glomerular basement membrane or within the glomerular basement membrane; mesangial proliferation and peripheral interposition; and inflow of inflammatory cells, mainly monocytes) have been discussed, and the role of hypocomplementemia and circulating nephritic factors (NFa and NFt) has been analyzed. Available evidence suggests that MCGN is an immunocomplex-mediated disease, the deposition of immune deposits being the initiating phenomenon, whereas the morphologic changes and complement system activation are secondary events.
We performed two trials. The former was a multicentric trial on 24 untreated patients with nephrotic syndrome due to membranous nephropathy to ascertain whether or not a long-term reduction of protein intake reduces urinary protein loss. In a randomized cross-over design the patients ate sequentially each for 3 months a normal protein diet (1.1 +/- 0.3 g/kg/day of proteins) and a low-protein diet (0.7 +/- 0.1 g/kg/day). Both diets were low in fat (< 30% of total calories). Neither urinary protein excretion nor serum albumin concentration were significantly different at the end of the low protein diet period or the normal protein diet period. We found that after 6 months of dietary manipulation serum total and LDL-cholesterol were reduced by 24 and 27% from the values at the beginning of the run-in period, also the mean 24 h proteinuria was significantly lower. In the later trial, after a baseline control period of 2 months on free diet, 20 untreated nephrotic patients were fed for two months a vegetarian soy diet, low in fat (28% of total calories) and in proteins (0.71 +/- 0.36 g/kg ideal body weight/day). At the end of the diet period all patients ate the same free diet as in the baseline period for 2 more months. The soy diet induced highly significant decreases in total serum cholesterol (28%). LDL-cholesterol (33%), apolipoprotein B (19%), urinary protein excretion (32%), that reversed on discontinuation of the diet.(ABSTRACT TRUNCATED AT 250 WORDS)
Three cases of chronic gastrointestinal bleeding are described; the Authors emphasize the important role of mesenteric arteriography in establishing site and nature of bleeding. The review of international literature shows a success rate between 41 and 73% of cases studied with this method after negativity of other diagnostic procedures.
The abnormalities of lipid metabolism in nephrotic syndrome consist in an increase in total and low-density lipoprotein (LDL) cholesterol, apolipoproteins B (ApoB), C-II and C-III, associated in patients with heavier or marked hypoalbuminemia with an increase in triglycerides and very low-density lipoprotein (VLDL) cholesterol, while the high-density lipoproteins (HDL) are distributed abnormally (increased HDL3 fraction and decreased HDL2 fraction) and the Apo A-I to Apo B ratio is reduced. Both increased hepatic lipoprotein synthesis and reduced removal capacity contribute to this hyperlipidemia. Proteinuria may lead to the lipoprotein abnormalities through stimulation of VLDL synthesis by the liver induced by hypoalbuminemia, although it has been more recently suggested that urinary protein loss is associated with the urinary loss of some important cofactor for the regulation of lipid synthesis or catabolism. Treatment of lipid abnormalities in patients with long-lasting heavy proteinuria is mandatory, because they may cause or contribute to accelerated atherosclerosis, but also because they appear to accelerate progression of renal disease by favouring mesangial sclerosis. Four groups of lipid-lowering drugs have been tested: 1) bile acid-binding resins; 2) fibric acid; 3) probucol; 4) inhibitors of HMG CoA reductase. The drugs of the last group appear to be effective and safe in short-term experiments, but long-term studies are necessary to confirm their validity. A dietary approach, consisting in a strictly vegetarian soy diet, very rich in poly- and monounsaturates fatty acids, has been recently tested by the author, with very promising results.
Male sex, age, cirrhosis, and HBsAg are the major risk factors for hepatocellular carcinoma (HCC). The geographic distribution of HCC is highly uneven, such that three distinct incidence areas are recognized. To clarify the reason(s) for this geographic variability of HCC, the risk factors in each incidence area were assessed. In parallel with the geographic distribution of HCC, HBsAg prevalence was highest in both HCC patients and in general population in Africa and Asia, where mothers of HCC patients are frequently HBsAg-positive, suggesting that hepatitis B virus hyperendemicity and perinatal infection account for the high HCC incidence in these areas. Cirrhosis, which is found on autopsy in 80% of the cases of HCC patients worldwide, is the most prevalent risk factor for HCC in areas where hepatitis B virus infection is less common. However, HBsAg carriage adds to the HCC risk carried by cirrhosis and explains the higher incidence of HCC in cirrhotics from Africa and Asia as well as elsewhere. Available data suggest that chronic HCV infection is a risk factor for cirrhosis and HCC. HBV vaccination should decrease HCC incidence rates worldwide; however, HCC prevention in regions where HBsAg carriage is infrequent may also require prevention of the other causes of cirrhosis in order for HCC rates to decline.
We studied the effect of dietary protein restriction on glomerular function and proteinuria in nine patients with membranous nephropathy. Patients were randomly assigned to a 3-month period of a normal protein diet (NPD, 1.3 mg/kg/d) or of a low-protein diet (LPD, 0.6 mg/kg/d), in a cross-over design. Dietary protein restriction did not affect glomerular filtration rate (47.8 +/- 10.7 and 49.0 +/- 13.5 mL/min/1.73 m2, LPD and NPD, respectively) and renal plasma flow (456 +/- 119 and 499 +/- 161 mL/min/1.73 m2, LPD and NPD, respectively), nor did it significantly improve glomerular permselective function, as shown by urinary protein excretion (3.1 +/- 2.2 and 3.5 +/- 2.8 g/d, LPD and NPD, respectively) and fractional clearance of albumin, IgG, and neutral dextran molecules of graded molecular size (radii ranging from 2.8 to 6.0 nm). These results indicate that reduction of protein intake to 0.6 g/kg/d does not improve glomerular size selectivity in membranous nephropathy. Thus, in current clinical practice, a protein-restricted diet does not appear to be effective in reducing proteinuria in this category of patients.
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