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M Gismondi

Publications and source records attributed to M Gismondi.

5 recordsLinked to original sources
PubMed2005

Exo-enzymatic activities and dissolved organic pools in relation with mucilage development in the Northern Adriatic Sea.

We tested the hypothesis that the appearance of mucilage in the Northern Adriatic Sea was related with the accumulation of dissolved organic compounds released by intensive enzymatic activities and not utilized as direct substrate for microbial growth. To do this enzymatic activities and dissolved organic and inorganic pools in periods characterized by the presence of mucilage and in the same seasons but in absence of mucilage were compared. Extracellular enzymatic activities (aminopeptidase, beta-glucosidase and alkaline phosphatase), nutrient pool concentrations (total dissolved nitrogen, dissolved organic nitrogen, total dissolved phosphorus, dissolved organic phosphorus) and the biochemical composition of particulate and dissolved organic matter (in terms of proteins and carbohydrates) were determined on a monthly basis over a period of 3 years. Aminopeptidase and alkaline phosphatase activities displayed higher values in springs preceding the appearance of mucilage than in spring when no mucilage was observed. Beta-Glucosidase activity showed significantly higher values in summer periods characterized by the massive production of mucilage than in summers without mucilage events. The months preceding mucilage events were also characterized by an increase of the alkaline phosphatase to aminopeptidase activity ratio and by a significant accumulation of dissolved proteins. These findings, together with the significant increase of the DON/DOP ratio, suggest that mucilage formation is favoured by the deficiency of organic P. The present study provides compelling evidences that mucilage formation is favoured by the unbalance between organic matter mobilization by enzymatic activities and the accumulation of labile dissolved organic-N compounds.

Alkaline Phosphatase↗
PubMed2001

Downward fluxes of particulate carbon, nitrogen and phosphorus in the north-western Adriatic sea.

Downward fluxes of particles, organic carbon, total nitrogen and total phosphorus and the composition of the settled particulate matter were determined in the north-western Adriatic Sea at two coastal sites influenced by the outflows of the Po and Adige rivers and one offshore site. Vertical fluxes were strongly influenced by resuspension processes in addition to the primary flux and advection. The resuspended material contributed on average 34-43% of the total matter sedimented in the near bottom traps in coastal waters. Net annual vertical fluxes (due to primary flux and advection) of organic carbon, total nitrogen and phosphorus in the coastal stations were: 71-97 g C m(-2) year(-1), 8-14 g N m(-2) year(-1) and 2.1-2.3 g P m(-2) year(-1), with the highest values recorded at the station off the Po river delta. The offshore site was characterised by net annual fluxes of particulates, C, N and P approximately one order of magnitude lower than the above. The carbon export to the bottom was limited in the warm seasons when it constituted only 2-9% of primary production, due to high recycling and utilisation in the upper layer of the water column, increasing up to 8-18% in winter because of the instability of the water column and low biological utilisation.

Carbon↗
PubMed1993

Antigen sensitivity evaluated by tear-specific and serum-specific IgE, skin tests, and conjunctival and nasal provocation tests in patients with ocular allergic disease.

The potential for ocular allergic patients to have a site-specific antigen sensitisation was investigated using various diagnostic tests of allergen sensitivity in subjects with allergic conjunctivitis (AC: n = 135), vernal keratoconjunctivitis (VK: n = 20), rhinoconjunctivitis (n = 20) or rhinitis (N = 10). In the AC and VK patients, skin tests and conjunctival provocation tests (CPT) were performed, and the levels of specific IgE in serum and in tears were identified. A subgroup of 36 patients was also challenged with a nasal-specific provocation test (NPT). Results showed a poor correlation between skin test results and tear-specific IgE, and also between serum-specific IgE and tear-specific IgE in both AC and VK patients (K < 0.3). CPT and tear IgE were significantly correlated (K = 0.5) in the ocular allergic population. In patients with rhinoconjunctivitis or rhinitis, and in 10 normal subjects, results of CPT and NPT were in 100% agreement. Conversely, in patients with only conjunctivitis, little correlation was found between the results of CPT and NPT (K = 0.3). Tear-specific IgE was the only positive diagnostic sign of antigen sensitivity in 35% of VK patients and 30% of AC patients. These results suggest that the conjunctiva can be a uniquely sensitised target organ in allergic patients.

Conjunctiva↗
PubMed1990

Correlation between conjunctival provocation test (CPT) and systemic allergometric tests in allergic conjunctivitis.

In order to assess the potential usefulness of CPT as a diagnostic tool for ocular allergy, the correlation between skin/RAST tests and CPT was determined in 144 patients affected by allergic 'hay fever' type conjunctivitis. The results showed that an agreement between skin/RAST tests and CPT occurred in 71% of the cases (130/183). Of the 29% uncorrelated cases, 23% (43/183) were positive for at least one specific antigen by skin/RAST tests but not by CPT, while 6% (10/183) were positive for at least one specific antigen by CPT, but not by skin/RAST tests. CPT dramatically increased the histamine levels in tears (p less than 0.001). These findings show that (1) systemic tests can be misleading in that they may suggest a specific sensitisation which, in fact, does not involve the conjunctiva (systemic test positive/CPT negative); (2) CPT can identify local conjunctival sensitisation in the absence of a systemic sensitisation (systemic test negative/CPT positive); (3) CPT can demonstrate that allergic 'hay fever' type conjunctivitis may be related to allergens different from those responsible for a systemic sensitisation.

Adolescent↗