Alberto Notarbartolo

Thromboxane Biosynthesis and Platelet Function in Type II Diabetes Mellitus

It has been suggested that platelet hyperreactivity in patients with diabetes mellitus is associated with increased platelet production of thromboxane. We therefore compared the excretion of a thromboxane metabolite and platelet function in 50 patients with Type II diabetes mellitus who had normal renal function and clinical evidence of macrovascular disease and in 32 healthy controls. The mean (+/- SD) excretion rate of urinary 11-dehydro-thromboxane B2 was significantly higher in the patients than in the controls (5.94 +/- 3.68 vs. 1.50 +/- 0.79 nmol per day; P less than 0.001), irrespective of the type of macrovascular complication. Tight metabolic control achieved with insulin therapy reduced the levels of 11-dehydro-thromboxane B2 by approximately 50 percent. The fractional conversion of exogenous thromboxane B2 (infused at a rate of 4.5, 45.3, or 226.4 fmol per kilogram of body weight per second) to urinary 11-dehydro-thromboxane B2 was assessed in four patients, in whom it averaged 5.4 +/- 0.1 percent; this value did not differ from that measured in healthy subjects. Aspirin in low doses (50 mg per day for seven days) reduced urinary excretion of the metabolite by approximately 80 percent in four patients. The fact that thromboxane biosynthesis recovered over the following 10 days was consistent with a platelet origin of the urinary metabolite.(ABSTRACT TRUNCATED AT 250 WORDS)

Intolerance of Cow's Milk and Chronic Constipation in Children

Background: Chronic diarrhea is the most common gastrointestinal symptom of intolerance of cows milk among children. On the basis of a prior open study, we hypothesized that intolerance of cows milk can also cause severe perianal lesions with pain on defecation and consequent constipation in young children. Methods: We performed a double-blind, crossover study comparing cows milk with soy milk in 65 children (age range, 11 to 72 months) with chronic constipation (defined as having one bowel movement every 3 to 15 days). All had been referred to a pediatric gastroenterology clinic and had previously been treated with laxatives without success; 49 had anal fissures and perianal erythoma or edema. After 15 days of observation, the patients received cows milk or soy milk for 2 weeks. After a one week washout period, the feedings were reversed. A response was defined as eight or more bowel movements during a treatment period. Results: Forty-four of the 65 children (68 percent) had a response while receiving soy milk. Anal fissures and pain with defecation resolved. None of the children who received cows milk had a response. In all 44 children with a response, the response was confirmed with a double blind challenge with cows milk. Children with a response had a higher frequency of coexistent rhinitis, dermatitis, or bronchospasm than those with no response (11 of 44 children vs. 1 of 21, P = 0.05); they were also more likely to have anal fissures and erythema or edema at base line (40 of 44 vs. 9 of 21, P < 0.001), evidence of inflammation of the rectal mucosa on biopsy (26 of 44 vs. 5 of 21, P = 0.008), and signs of hypersensitivity, such as specific IgE antibodies to cows-milk antigens (31 of 44 vs. 4 of 21, p < 0.001). Conclusions: In young children, chronic constipation can be a manifestation of intolerance of cows milk.

Inhibition of Thromboxane Biosynthesis and Platelet Function by Simvastatin in Type IIa Hypercholesterolemia

Abstract Thromboxane A2 (TXA2) biosynthesis is enhanced in the majority of patients with type IIa hypercholesterolemia. Because simvastatin (a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor) was previously shown to reduce platelet aggregation and TXB2 production ex vivo, we investigated TXA2 biosynthesis and platelet function in 24 patients with type IIa hypercholesterolemia randomized to receive in a double-blind fashion simvastatin (20 mg/d) or placebo for 3 months. The urinary excretion of 11-dehydro-TXB2, largely a reflection of platelet TXA2 production in vivo, was measured by a previously validated radioimmunoassay technique. Blood lipid levels and urinary 11-dehydro-TXB2 excretion were significantly ( P <.001) reduced by simvastatin. In contrast, placebo-treated patients did not show any statistically significant changes in either blood lipids or 11-dehydro-TXB2 excretion. The reduction in 11-dehydro-TXB2 associated with simvastatin was correlated with the reduction in total cholesterol ( r =.81, P <.0001), LDL cholesterol ( r =.79, P <.0001), and apolipoprotein B ( r =.76, P <.0001) levels. Platelets from patients with type IIa hypercholesterolemia required significantly ( P <.01) more collagen and ADP to aggregate and synthesized less TXB2 in response to both agonists after simvastatin therapy. Bleeding time, platelet sensitivity to Iloprost, and blood lipoprotein(a) and HDL cholesterol levels were not significantly affected by either treatment. We conclude that enhanced TXA2 biosynthesis in type IIa hypercholesterolemia is, at least in part, dependent on abnormal cholesterol levels and/or other simvastatin-sensitive mechanisms affecting platelet function.

Gastroesophageal reflux and cow's milk allergy in infants : A prospective study

BACKGROUND Recent reports have suggested that gastroesophageal reflux in pediatric patients may be caused by food allergy. OBJECTIVE The aim of our study was to determine the frequency of the association of gastroesophageal reflux with cows milk protein allergy in patients win the first year of life. METHODS We studied 204 consecutive patients (median age, 6.3 months) who had been diagnosed as having gastroesophageal reflux on the basis of 24-hour continuous pH monitoring and histologic examination of the esophageal mucosa. RESULTS Clinical history suggested diagnosis of cows milk allergy in 19 infants, and 93 others had positive test results (serum IgE anti-lactoglobulin, prick tests, circulating or fecal or nasal mucus eosinophils) but did not have symptoms indicating cows milk allergy. The cows milk-free diet and two successive blind challenges confirmed the diagnosis of cows milk allergy in 85 of the 204 patients with gastroesophageal reflux. The clinical presentations of the infants with gastroesophageal reflux alone were different, in view of the greater frequency of diarrhea (p less than 0.0001) and atopic dermatitis (p less than 0.0002). In all, gastroesophageal reflux was associated with, and probably caused by cows milk allergy, in 85 of 204 cases (41.8%). CONCLUSIONS Considering the frequency of this association, patients younger than 12 months old with symptoms of gastroesophageal reflux should be carefully examined to determine whether this disorder is primary or caused by cows milk allergy.

Increased thromboxane biosynthesis in type IIa hypercholesterolemia.

BackgroundIncreased platelet thromboxane (TX)A2 production has been described in type IIa hypercholesterolemia. To verify the relevance of these capacity-related measurements to the actual rate of TXA2 biosynthesis in vivo, we studied the urinary excretion of its major enzymatic metabolites in 46 patients with type hIa hypercholesterolemia and 20 age-matched controls. Methods and ResultsUrinary 11-dehydro-TXB2 and 2,3-dinor-TXB2 were measured by previously validated radioimmunoassays. The excretion rate of 11-dehydro-TXB2 was significantly (p < 0.001) higher in patients (68.7±35.1 ng/hr, mean±SD) than in controls (22.4±9.4 ng/hr), with metabolite excretion >2 SD of the normal mean in 74% of the patients. Urinary 11-dehydro-TXB2 was significantly (p < 0.01) correlated with the threshold aggregating concentration of collagen (r = −0.641) and arachidonate (r = −0.734) and with agonist-induced platelet TXB2 production in vitro (r = 0.647 and 0.748, respectively). Moreover, a statistically significant correlation (r = 0.673, p < 0.001, n = 66) was found between 11-dehydro-TXB2 excretion and total plasma cholesterol. The enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor simvastatin (20 mg/day for 6 months) significantly reduced cholesterol levels by 22–28% and urinary 11-dehydro-TXB2 excretion by 32–42% in 10 patients. However, the reduction in the latter did not correlate with the reduction in the former and may have resulted from a nonspecific effect of simvastatin. Moreover, selective inhibition of platelet cyclooxygenase activity by low-dose aspirin (50 mg/day for 7 days) was associated with cumulative inhibition of 11-dehydro-TXB2 excretion by approximately 70% in six patients. ConclusionsTXA2 biosynthesis is enhanced in the majority of patients with type lla hypercholesterolemia; this is, at least in part, a consequence of abnormal cholesterol levels, as suggested by the correlation between the two. Low-dose aspirin can largely suppress increased metabolite excretion, thus suggesting that it reflects TXA2-dependent platelet activation in vivo.

Sideropenic anemia and celiac disease: one study, two points of view.

Recent studies have pointed to the relationshipbetween iron deficiency anemia and celiac disease,although data on the prevalence of celiac disease inanemic patients have been conflicting, and there is no agreement on the best screening procedurefor CD in these patients. Our aims were to evaluate therelationship between anemia and celiac disease (CD) fromtwo different points of view — the hematology clinic and the pediatric gastroenterologydepartment — and to evaluate the utility ofanti-endomysial antibody determination in screeninganemic patients for CD using human umbilical cord assubstrate. We studied 130 patients with CD (58 males, 72females; median age 18 months) diagnosed at a departmentof Pediatric Gastroenterology, and 85 patients with irondeficiency anemia (38 males, 47 females; median age 48 years) observed at a hematologyoutpatient clinic. From the 85 adult patients with irondeficiency anemia, we selected a subgroup of 25 subjectswith no improvement in Hb after two months of iron therapy (80 mg/day orally). Routinehematochemical tests were performed in all 215 patients.All pediatric and adult subjects underwent immunologicalscreening for celiac disease (AGA and EmA assay);intestinal biopsy was also performed on patients testingpositive. In the adult anemic patients a serum samplewas stored at –20°C on first observation, andafter 6-18 months EmA on human umbilical cord wereassayed. In the pediatric patients with CD, anemia wasobserved in 91/130 patients (70% of cases, the mostfrequent symptom after poor growth); however, this wasthe only presenting symptom of CD in 2/130 patients (1.5% of cases). Anemia was sideropenic in41/91 patients (iron <45 μg/dl, ferritin <15mug/liter). In the adult patients with iron deficiencyanemia, immunological screening (AGA and EmA) showed suspected CD in 5/85 cases (5.8%), withdiagnosis confirmed on intestinal biopsy. These fivepatients were in the subgroup of iron supplementationtherapy nonresponders. CD prevalence in the refractory anemia subgroup was, therefore, 5/25 (20%). Ondiagnosis the hematological indices of the anemia + CDpatients were not different than those of the refractoryanemia patients without CD. The median age of the CD + anemia patients was significantlylower than that of the whole group of anemic subjects,and there was also a prevalence of females (4/5 cases).The results of the EmA determination on human umbilical cord in the adult anemic patientsshowed a perfect concordance with those using atraditional kit that uses monkey esophagus as substrate.In the pediatric age group many cases of CD with anemia as the only sign of the disease are probablynot diagnosed. In our adult patients with sideropenicanemia, CD prevalence was 5-6%; however, the observationof anemic patients not responding to oral iron therapy makes a diagnosis of CD much moreprobable. EmA determination on human umbilical cord isthe most logical approach to screen anemic patients forsuspected CD.

Effects of a phytosterol-enriched dairy product on lipids, sterols and 8-isoprostane in hypercholesterolemic patients: A multicenter Italian study

BACKGROUND AND AIMS Plant sterols, added to several food sources, lower serum cholesterol concentrations. Plant sterol-induced cholesterol lowering is paralleled by a mild decrease in plasma levels of the antioxidant beta-carotene, the amount of this decrease being considered clinically non-significant. Whether the effect on lipid profile of daily consumption of plant sterol-enriched low-fat fermented milk (FM) is paralleled by a concomitant variation in a reliable marker of the oxidative burden like plasma isoprostane levels is unresolved. METHODS AND RESULTS The effect of plant sterol consumption on plasma lipid and isoprostane levels of hypercholesterolemic patients was evaluated in a multicenter, randomized double blind study. Hypercholesterolemic patients consumed a FM daily for 6 weeks. Subjects were randomized to receive either 1.6g of plant sterol-enriched FM (n=60) or control FM product (n=56). After 6 weeks of plant sterol-enriched FM consumption, LDL cholesterol was reduced from 166.2+/-2.0 to 147.4+/-2.8 mg/dL (p=0.01). A significant reduction was observed for total cholesterol (from 263.5+/-2.6 to 231.0+/-3.2mg/dL, p=0.01). There was greater LDL cholesterol lowering among hypercholesterolemic patients with higher LDL cholesterol at baseline. We found a reduction of plasma 8-isoprostane in patients taking plant sterol-enriched FM (from 43.07+/-1.78 to 38.04+/-1.14 pg/ml, p=0.018) but not in patients taking the control product (from 42.56+/-2.12 to 43.19+/-2.0 pg/ml, p=NS). Campesterol and beta-sitosterol levels were not influenced by phytosterol consumption. CONCLUSIONS Daily consumption of low-fat plant sterol dairy product favourably changes lipid profile by reducing LDL-cholesterol, and may also have an anti-oxidative effect through a reduction of plasma isoprostanes.

Thromboxane B2 formation and platelet sensitivity to prostacyclin in insulin-dependent and insulin-independent diabetics.

TxB2 formation in PRP after thrombin stimulus, serum TxB2 and platelet sensitivity to prostacyclin and the correlation with ambient fasting plasma glucose and lipoproteins were determined in 20 insulin-independent diabetics (IID) with macroangiopathy, 10 insulin-dependent diabetics (IDD) with microangiopathy and 30 matched controls. Platelets obtained from insulin-independent diabetics synthetize significantly higher amounts of TxB2 than those of insulin-dependent diabetics and matched controls. IDD and IID patients required significantly higher concentrations of prostacyclin (p less than 0.001) for a similar degree of platelet aggregation inhibition. The amount of prostacyclin required for 50% platelet aggregation inhibition was correlated with fasting plasma glucose (r = 0.64, p less than 0.001) and HbA1% (r = 0.48, p less than 0.01) in all diabetic subjects. We conclude that: 1) only PRP, obtained from some insulin-independent diabetics with a concomitant macroangiopathy, shows an increased synthesis of TxB2; 2) platelet sensitivity to prostacyclin is highly dependent on the fasting ambient plasma glucose.

Guinea pig transglutaminase immunolinked assay does not predict coeliac disease in patients with chronic liver disease

BACKGROUND It has been suggested that serological screening for coeliac disease (CD) should be performed in patients with chronic unexplained hypertransaminasaemia. AIMS To evaluate the specificity for CD diagnosis of serum IgA antitissue transglutaminase (tTG) determination in consecutive patients with chronic hypertransaminasaemia using the most widely utilised ELISA based on tTG from guinea pig as the antigen. PATIENTS AND METHODS We studied 98 patients with chronic hypertransaminasaemia, evaluated for the first time in a hepatology clinic. Serum anti-tTG and antiendomysial (EmA) assays were performed. Patients positive for EmA and/or anti-tTG were proposed for intestinal biopsy. Finally, all sera were reassayed for anti-tTG using an ELISA based on human recombinant tTG as the antigen. RESULTS A total of 94/98 hypertransaminasaemic patients were positive for hepatitis virus markers, with 82/98 (83%) positive for anti-hepatitis C virus. Liver histology showed that most patients had mild or moderate chronic hepatitis while severe fibrosis or overt liver cirrhosis was found in 20/98. CD screening showed that 15/98 (16%) hypertransaminasaemic subjects had anti-tTG values in the same range as CD patients; however, IgA EmA were positive in only 2/98 (2%). Distal duodenal biopsy, performed in nine patients, showed subtotal villous atrophy in the two EmA+/anti-tTG+ patients but was normal in 7/7 EmA−/anti-tTG+ subjects. The presence of anti-tTG+ values in EmA− patients was unrelated to particular gastrointestinal symptoms, other associated diseases, severity of liver histology, or distribution of viral hepatitis markers. There was a significantly higher frequency of positive serum autoantibodies (antinuclear, antimitochondrial, antismooth muscle, and anti-liver-kidney microsomal antibodies) in anti-tTG+/EmA− patients than in the other subjects (9/13v 10/83; p<0.003). Also, a correlation was found between serum gamma globulin and anti-tTG values (p<0.01). When sera were tested with the ELISA based on human tTG as the antigen, no false positive results were observed: only the two EmA+ patients with atrophy of the intestinal mucosa were positive for anti-tTG while all others were negative, including those false positive in the ELISA based on guinea pig tTG as the antigen. CONCLUSIONS In patients with elevated transaminases and chronic liver disease there was a high frequency of false positive anti-tTG results using the ELISA based on tTG from guinea pig as the antigen. Indeed, the presence of anti-tTG did not correlate with the presence of EmA or CD. These false positives depend on the presence of hepatic proteins in the commercial tTG obtained from guinea pig liver and disappear when human tTG is used as the antigen in the ELISA system. We suggest that the commonly used tTG ELISA based on guinea pig antigen should not be used as a screening tool for CD in patients with chronic liver disease.

Exocrine pancreatic function in children with coeliac disease before and after a gluten free diet.

This study was designed to determine the extent of pancreatic insufficiency in untreated coeliac disease and whether pancreatic secretion is impaired after a prolonged gluten free period. Three groups of patients were studied: group A comprised 44 patients, mean (SD) age 4.0 (3.1) years, with coeliac disease and total or subtotal atrophy of the intestinal mucosa; group B comprised 67 patients, mean age 4.4 (3.0) years, with coeliac disease but with normal morphology of the intestinal villi (after 12.9 months of a gluten free diet); group C comprised 49 control subjects, mean age 3.2 (3.0) years, with normal jejunal histology. In all subjects exocrine pancreatic function was determined by the secretin-caerulein test; bicarbonate concentration and lipase, phospholipase, and chymotrypsin activity were measured after an intravenous injection of secretin 1 clinical unit (CU) + caerulein 75 ng/kg body weight. Faecal chymotrypsin concentration was also assayed. No significant difference was found between values of the duodenal output of pancreatic enzymes and bicarbonate obtained in the three groups; however, 10 of 44 untreated coeliac patients showed tryptic or lipolytic activity, or both, below the normal limit for our laboratory. The mean value of the faecal chymotrypsin concentration was significantly lower in untreated than in treated coeliac patients (p less than 0.0001) or in control subjects (p less than 0.0001). It is concluded that untreated coeliac patients may have pancreatic deficiency independent of a decrease in enterohormone release. No primary or secondary pancreatic insufficiency was found in coeliac patients where the intestinal mucosa had returned to normal.