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M Tumminello

Publications and source records attributed to M Tumminello.

7 recordsLinked to original sources
PubMed2005

A tool for filtering information in complex systems.

We introduce a technique to filter out complex data sets by extracting a subgraph of representative links. Such a filtering can be tuned up to any desired level by controlling the genus of the resulting graph. We show that this technique is especially suitable for correlation-based graphs, giving filtered graphs that preserve the hierarchical organization of the minimum spanning tree but containing a larger amount of information in their internal structure. In particular in the case of planar filtered graphs (genus equal to 0), triangular loops and four-element cliques are formed. The application of this filtering procedure to 100 stocks in the U.S. equity markets shows that such loops and cliques have important and significant relationships with the market structure and properties.

Journal Article↗
PubMed1998

Intolerance of cow's milk and chronic constipation in children.

BACKGROUND: Chronic diarrhea is the most common gastrointestinal symptom of intolerance of cow's milk among children. On the basis of a prior open study, we hypothesized that intolerance of cow's 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 cow's 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 erythema or edema. After 15 days of observation, the patients received cow's milk or soy milk for two 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 cow's milk had a response. In all 44 children with a response, the response was confirmed with a double-blind challenge with cow's 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 cow's-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 cow's milk.

Animals↗
PubMed1998

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

Recent studies have pointed to the relationship between iron deficiency anemia and celiac disease, although data on the prevalence of celiac disease in anemic patients have been conflicting, and there is no agreement on the best screening procedure for CD in these patients. Our aims were to evaluate the relationship between anemia and celiac disease (CD) from two different points of view--the hematology clinic and the pediatric gastroenterology department--and to evaluate the utility of anti-endomysial antibody determination in screening anemic patients for CD using human umbilical cord as substrate. We studied 130 patients with CD (58 males, 72 females; median age 18 months) diagnosed at a department of Pediatric Gastroenterology, and 85 patients with iron deficiency anemia (38 males, 47 females; median age 48 years) observed at a hematology outpatient clinic. From the 85 adult patients with iron deficiency anemia, we selected a subgroup of 25 subjects with no improvement in Hb after two months of iron therapy (80 mg/day orally). Routine hematochemical tests were performed in all 215 patients. All pediatric and adult subjects underwent immunological screening for celiac disease (AGA and EmA assay); intestinal biopsy was also performed on patients testing positive. In the adult anemic patients a serum sample was stored at -20 degrees C on first observation, and after 6-18 months EmA on human umbilical cord were assayed. In the pediatric patients with CD, anemia was observed in 91/130 patients (70% of cases, the most frequent symptom after poor growth); however, this was the only presenting symptom of CD in 2/130 patients (1.5% of cases). Anemia was sideropenic in 41/91 patients (iron <45 microg/dl, ferritin <15 microg/liter). In the adult patients with iron deficiency anemia, immunological screening (AGA and EmA) showed suspected CD in 5/85 cases (5.8%), with diagnosis confirmed on intestinal biopsy. These five patients were in the subgroup of iron supplementation therapy nonresponders. CD prevalence in the refractory anemia subgroup was, therefore, 5/25 (20%). On diagnosis the hematological indices of the anemia + CD patients were not different than those of the refractory anemia patients without CD. The median age of the CD + anemia patients was significantly lower 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 patients showed a perfect concordance with those using a traditional 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 probably not diagnosed. In our adult patients with sideropenic anemia, CD prevalence was 5-6%; however, the observation of anemic patients not responding to oral iron therapy makes a diagnosis of CD much more probable. EmA determination on human umbilical cord is the most logical approach to screen anemic patients for suspected CD.

Anemia, Iron-Deficiency↗
PubMed1997

Use of 24-hour oesophageal pH-metry for the detection of gastro-oesophageal reflux in infants: what is the ideal score and the optimal threshold? A receiver-operating-characteristic analysis.

BACKGROUND: The search for the ideal score and best cut-off value to interpret the data from 24-hour continuous pH-monitoring interests both gastroenterologists with adult patients and paediatric gastroenterologists. AIMS: To evaluate 24-hour continuous pH monitoring as a discriminatory test in the diagnosis of gastro-oesophageal reflux disease in a paediatric population, using various pH-metry scores and cut-off values. PATIENTS: One hundred and one patients presenting gastro-oesophageal reflux disease (endoscopic diagnosis of oesophagitis or coincidence between apnoea and reflux episodes observed during pH-metry), median age 10 months, were studied, together with a control group of 84 subjects, median age 11 months. RESULTS: After plotting the receiver operating characteristic curves and calculating the area below them, the evaluation of the total percentage reflux time proved to have a higher capacity for distinguishing between the patients and controls than the Euler score (p < 0.05). The cut-off value of 5.2% for the total percentage reflux time had a sensitivity of 75% and was 88% specific. Using higher cut-off values according to age, a 95% specificity and a 49% sensitivity were obtained. The most sensitive score was the Jolley score: 96% with a cut-off of 64 and 90% with a cut-off of 100 (a value determining the maximum diagnostic accuracy); specificity, however, was low: 39-61%. In addition, the Jolley score was the most useful parameter in detecting patients with apnoeic episodes secondary to gastro-oesophageal reflux disease and allowed a correct diagnosis in 12/13 cases. CONCLUSIONS: a) The simple determination of total percentage reflux time, according to the methodology used, has a higher predictive capacity than the more complex pH-monitoring scores; b) the best cut-off value for total percentage reflux time is 5.2% as it combines a good specificity and sensitivity which are necessary for this test; c) age-dependent cut-off values are highly specific but sensitivity is much too low; d) the Jolley score is very sensitive and this was maintained even when the cut-off was raised to a value of 100; it is the best predictive score for episodes of gastro-oesophageal reflux-dependent apparent life-threatening events.

Adult↗
PubMed1996

Clinical and pH-metric characteristics of gastro-oesophageal reflux secondary to cows' milk protein allergy.

AIMS: The primary aim was to assess whether there were differences in symptoms, laboratory data, and oesophageal pH-metry between infants with primary gastro-oesophageal reflux and those with reflux secondary to cows' milk protein allergy (CMPA). PATIENTS AND METHODS: 96 infants (mean(SD) age 7.8(2.0) months) with either primary gastro-oesophageal reflux, reflux with CMPA, CMPA only, or none of these (controls) were studied. Symptoms, immunochemical data, and oesophageal pH were compared between the four groups and the effect of a cows' milk protein-free diet on the severity of symptoms was also assessed. RESULTS: 14 out of 47(30%) infants with gastro-oesophageal reflux had CMPA. These infants had similar symptoms to those with primary gastro-oesophageal reflux but higher concentrations of total IgE and circulating eosinophils (p < 0.005) and IgG anti-beta lactoglobulin (p < 0.003). A progressive constant reduction in oesophageal pH at the end of a feed, which continued up to the next feed, was seen in 12 out of 14 patients with gastro-oesophageal reflux secondary to CMPA and in 24 of 25 infants with CMPA only. No infants with primary gastro-oesophageal reflux and none of the controls had this pattern. A cows' milk protein-free diet was associated with a significant improvement in symptoms only in infants with gastro-oesophageal reflux with CMPA. CONCLUSION: A characteristic oesophageal pH pattern is useful in distinguishing infants with gastro-oesophageal reflux associated with CMPA.

Diagnosis, Differential↗
PubMed1996

Gastroesophageal reflux associated with cow's milk allergy in infants: which diagnostic examinations are useful?

Gastroesophageal reflux (GER) in infants can be secondary to food allergy. We have evaluated the frequency with which GER is associated with cow's milk protein allergy (CMPA) in infants < 1 yr old and tried to indicate the laboratory and instrumental examinations useful in diagnosing GER + CMPA. We studied 140 infants (60 M, 80 F), mean age 6.0 +/- 2.8 months. After 24-h esophageal pH-metry, esophageal endoscopy, and elimination diet, followed by a double-blind challenge, the patients were divided into four groups: primary GER, GER secondary to CMPA, CMPA without GER, and a control group with subjects suffering from neither GER nor CMPA. Thirty of 72 patients with GER were also suffering from CMPA. No differences were observed as regards age, sex, symptoms, and clinical or family history between patients with GER only and those with GER + CMPA. The immunological test most useful for GER + CMPA diagnosis was the IgG anti-beta-lactoglobulin assay: positive in 27/30 subjects with GER + CMPA and in 4/42 patients with GER only. We also observed a characteristic pattern of the pH-monitoring tracing in 26/30 patients with GER + CMPA but in none of the 42 patients with GER only. This consisted of a progressive, constant reduction in esophageal pH at the end of a feed, which continued up to the following feed, when pH rose steeply. We conclude that the evidence of this characteristic tracing and of a high IgG anti-beta-lactoglobulin value are specific and sensitive tests for GER + CMPA diagnosis.

Chi-Square Distribution↗