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Biomedical subjects

A Collina

Publications and source records attributed to A Collina.

At least 19 recordsLinked to original sources
PubMed1991

Syringopeptins, new phytotoxic lipodepsipeptides of Pseudomonas syringae pv. syringae.

The primary structure of some new lipodepsipeptides named syringopeptins, produced by plant pathogenic strains of Pseudomonas syringae pv. syringae has been determined by a combination of chemical methods, 1H and 13C NMR spectroscopy and FAB mass spectrometry. Two syringomycin-producing strains afforded 3-hydroxydecanoyl-Dhb-Pro-Val-Val-Ala-Ala-Val-Val-Dhb-Ala-Val-Ala- Ala-Dhb-aThr-Ser-Ala-Dhb-Ala-Dab-Dab-Tyr, with Tyr acylating a Thr to form a macrolactone ring, and smaller amounts of the 3-hydroxydodecanoyl homologue. Evidence was obtained that a third syringomycin-producing strain and a syringotoxin-producing strain synthesize 3-hydroxydecanoyl-Dhb-Pro-Val-Ala-Ala-Val-Leu-Ala-Ala-Dhb-Val-Dhb- Ala-Val-Ala-Ala-Dhb-aThr-Ser-Ala-Val-Ala-Dab-Dab-Tyr, with Tyr and aThr forming again the macrolactone ring, and smaller amounts of the 3-hydroxydodecanoyl homologue.

Amino Acid Sequence↗
PubMed1990

Structure of syringotoxin, a bioactive metabolite of Pseudomonas syringae pv. syringae.

The covalent structure of syringotoxin, a bioactive metabolite of Pseudomonas syringae pv. syringae isolates, pathogenic on various species of citrus trees, has been deduced from 1D and 2D 1H- and 13C-NMR spectra combined with extensive FAB-MS data and results of some chemical reactions. Similarly to syringomicins and syringostatins, produced by other plant pathogenic strains of P. syringae pv. syringae, syringotoxin is a lipodepsinonapeptide. Its peptide moiety corresponds to Ser-Dab-Gly-Hse-Orn-aThr-Dhb-(3-OH)Asp-(4-Cl)Thr with the terminal carboxy group closing a macrocyclic ring on the OH group of the N-terminal Ser, which in turn is N-acetylated by 3-hydroxytetradecanoic acid.

Amino Acid Sequence↗
PubMed1988

Immunoglobulin A antigliadin antibodies in jejunal juice: markers of severe intestinal damage in coeliac children.

Antibodies to gliadin (AGA), detected in jejunal juice by immunofluorescence and enzyme-linked immunosorbent assay, have been found in 13 of 15 (87%) children with untreated coeliac disease. Jejunal AGA were also positive in 6 of the 9 (67%) coeliac children on gluten challenge, while they were consistently negative in coeliac children on a gluten-free diet and in controls. Jejunal AGA were always of immunoglobulin A (IgA) class, associated with IgM in some cases. Moreover, the presence of IgA AGA in jejunal juice was strictly related to the severity of intestinal damage. These data suggest that IgA AGA, detected in jejunal juice are synthesized from gut mucosa and are markers of its abnormal function. Like AGA, antibodies to milk and egg proteins were only found in jejunal juice of coeliac patients with flat intestinal mucosa, but their prevalence was significantly lower than that of AGA.

Celiac Disease↗
PubMed1986

Antibodies to dietary antigens in coeliac disease.

Antibodies to gliadin (AGA) were found in 77 (94%) of 82 sera from patients with active coeliac disease (untreated and after gluten challenge). Although IgG AGA had a higher nosological sensitivity than IgA AGA (88% versus 67%), their nosological specificity was lower than that of IgA antibodies (87% versus 100%). The sensitivity of antibodies to casein, beta-lactoglobulin, and ovalbumin in active coeliac disease varied from 36% to 48% without significant difference between IgG and IgA antibodies. IgG and IgA antibodies to milk and egg proteins showed a specificity similar to that of AGA, although some IgA antibodies other than AGA were found in disease controls (Crohn's disease, ulcerative colitis, post-enteritis syndrome).

Adolescent↗
PubMed1985

Antibodies to gliadin detected by immunofluorescence and a micro-ELISA method: markers of active childhood and adult coeliac disease.

Antibodies to gliadin have been detected by immunofluorescence (IFL-AGA) and a micro-ELISA method (ELISA-AGA) in 45 out of 47 (96%) sera from patients with active childhood and adult coeliac disease. The two methods were more sensitive than R1-reticulin antibodies (R1-ARA) which were found only in 28 of the same patients (60%). R1-ARA were always negative in the 26 sera from patients with childhood coeliac disease and adult coeliac disease after gluten free diet, while IFL- and ELISA-AGA were respectively found in three (12%) and in four (15%) out of these patients. Moreover, while R1-ARA and IFL-AGA were strictly confined to coeliac disease. ELISA-AGA were occasionally found in patients with control diseases. These 'false positive' antibodies were all of IgG class and had low titres. In our experience IFL- and ELISA-AGA of IgA class were strictly confined to active childhood coeliac disease and adult coeliac disease. The detection of AGA is useful in monitoring the diet and in the follow up of coeliac disease. IFL- and ELISA-AGA, then, are to be preferred to R1-ARA for the screening of coeliac patients.

Adult↗
PubMed1984

R1 reticulin antibodies: markers of celiac disease in children on a normal diet and on gluten challenge.

R1 reticulin antibodies were found in sera from patients with childhood celiac disease (CCD). Although the overall sensitivity of R1 in the diagnosis of CCD was relatively low (16/43 = 37%), when only those cases in an active phase of the disease were considered, the sensitivity increased (16/24 = 67%). In spite of its low sensitivity, the R1 assay did show a high degree of specificity, as this antibody was not found in children with post-enteritis syndrome or in healthy controls. R1 antibodies, when found in active CCD, always turned out to be positive when tested on human liver as substrate. While this fact did not enhance the sensitivity of the test, it strengthened its specificity, since R1, found in pathological conditions other than CCD, was nearly always negative on human tissue. Although the R1 reticulin antibody test cannot replace jejunal biopsy in the diagnosis of CCD, its assay, particularly on human liver as substrate, can be considered a useful tool in the screening of celiac patients.

Animals↗
PubMed1983

Short stature and celiac disease: a relationship to consider even in patients with no gastrointestinal tract symptoms.

To determine the incidence of celiac disease in a group of nonselected children with short stature, duodenal biopsy was performed in 60 unselected children with short stature (below third centile) and absence of gastrointestinal tract symptoms. Examination revealed probable celiac disease in five children (8.3%). Analysis of the results of other tests that might possibly be considered as alternatives to biopsy (e.g., xylose test, antireticulin antibodies, gastrointestinal tract symptoms in the first two years of life, bone age, serum iron, iron load, triglyceride load) led us to conclude that no test or clinical measurement could have allowed us 100% certainty in making the correct diagnosis. None of the children with celiac disease had growth hormone deficiency. We conclude that asymptomatic celiac disease represents a cause of short stature that cannot be ignored, and that only by intestinal biopsy can all such patients be identified.

Adolescent↗
PubMed1982

Splenic function in childhood coeliac disease.

We measured splenic function using a simple, non-isotopic method in childhood coeliac disease. No patients were shown to have hyposplenism. This has important clinical and therapeutic implications.

Adolescent↗
PubMed1980

Serum bile acids in newborns and children.

A specific and sensitive radioimmunoassay for cholic, chenodeoxycholic, and lithocholic acid conjugates and for sulfolithocholylglycine was used to measure serum bile acids (BA) in infants and children. Elevated cholic and chenodeoxycholic acid values were observed in the first year of life in fasting infants. Newborn babies presented high levels of primary BA not correlated with those of the mothers. In premature newborn babies who had not yet been fed, meal induced a considerable reduction in the primary BA levels in serum. In normally fed babies, meal induced a significant increase in the primary BA levels in serum. These data suggest a progressive maturity throughout the first year of life of the serum BA determinants, i.e., gallbladder emptying, intestinal motility and absorption, and hepatic uptake.

Bile Acids and Salts↗
PubMed1975

Photochemically induced artifact in the analysis of soil for residues of organochlorine pesticides.

After solvent extraction of soil and clean-up of the extract there is a possibility of reactions being induced photochemically in the solvent phase. In one recent instance such reactions, proceeding relatively quickly during 6-8 days, produced unknown compound(s) whose retention time in a column of 10% DC-200 on 80/100 mesh Gas Chrom Q coincided with that of pp'-DDT. Such interference could be eliminated by later treatment of the extract with concentrated sulphuric acid.

Chromatography, Gas↗