Claudio Catini

Spatial analysis reveals alterations of parvalbumin- and calbindin-positive local circuit neurons in the cerebral cortex of mutant mdx mice

The aim of the present study was to investigate the spatial organization of selected populations of local circuit neurons in the cerebral cortex of the mutant mdx mouse, an acknowledged model of Duchenne Muscular Dystrophy. To this purpose, we quantified and compared the distribution of parvalbumin- and calbindin-positive neurons in the motor, somatosensory, visual, and anterior cingulate cortices of wild-type and mdx mice. The methodological approach was based on generation of two-dimensional Voronoi polygons from digital charts of the cell populations visualized immunohistochemically. Polygon areas were then analyzed and the derived coefficients of variation were statistically compared. Using this strategy, we were able to reveal, in mdx mice, changes involving both the above populations of interneurons. These changes were evident in the motor and anterior cingulate cortices but not in the somatosensory and visual cortices. In addition, the changes of coefficients of variation were area-specific in the cortex of mdx mice. The values increased in the motor cortex and decreased in the anterior cingulate cortex with respect to the corresponding values of wild-type animals. The present findings point out widespread alterations in the mdx cortex involving also areas not primarily related to sensorimotor integration. In addition, we demonstrate that cortical alterations of the local circuit machinery are characterized in mdx mice by individual regional differences.

Parvalbumin-positive GABAergic interneurons are increased in the dorsal hippocampus of the dystrophic mdx mouse.

Duchenne muscular dystrophy (DMD) is characterized by variable alterations of the dystrophin gene and by muscle weakness and cognitive impairment. We postulated an association between cognitive impairment and architectural changes of the hippocampal GABAergic system. We investigated a major subpopulation of GABAergic neurons, the parvalbumin-immunopositive (PV-I) cells, in the dorsal hippocampus of the mdx mouse, an acknowledged model of DMD. PV-I neurons were quantified and their distribution was compared in CA1, CA2, CA3, and dentate gyrus in wild-type and mdx mice. The cell morphology and topography of PV-I neurons were maintained. Conversely, the number of PV-I neurons was significantly increased in the mdx mouse. The percent increase of PV-I neurons was from 45% for CA2, up to 125% for the dentate gyrus. In addition, the increased parvalbumin content in the mdx hippocampus was confirmed by Western blot. A change in the hippocampus processing abilities is the expected functional counterpart of the modification displayed by PV-I GABAergic neurons. Altered hippocampal functionality can be responsible for part of the cognitive impairment in DMD.

Modification of plasma glycosaminoglycans in long distance runners

Background: It is well documented that exercise reduces the risk of thromboembolic disease, possibly by increasing the plasma concentration of anticoagulant-antithrombotic compounds. Objectives: As plasma glycosaminoglycans (GAGs) play a role in the anticoagulant-antithrombotic potential of plasma, to examine the concentration and profile of these compounds in well trained, long distance runners and sedentary subjects. Methods: Plasma GAGs were measured in 10 male, long distance runners and 10 sedentary counterparts before and after ergometric tests. GAGs were extracted, purified, and identified by electrophoretic and enzymatic methods, and measured as hexosamine. Results: Plasma GAGs found in sedentary subjects were slow migrating heparan sulphates I and II, keratan sulphate I, and chondroitin 4–6-sulphate. Those found in trained athletes were slow migrating heparan sulphate I, chondroitin 4–6-sulphate (or keratan sulphate I), and fast migrating heparan sulphate. Total plasma concentrations of GAGs were higher in athletes than in sedentary subjects at rest. In sedentary subjects, plasma GAGs did not change after cycle ergometric exercise at 80% of their anaerobic threshold. However, the appearance of a novel band of heparan sulphate migrating faster than fast migrating heparan sulphate was observed in athletes after exercise. Conclusions: Exercise changes the amount and profile of plasma GAGs; these changes may play a role in protecting subjects who practise aerobic sports against developing cardiovascular disease.

Heparin/heparan sulfate anticoagulant glycosaminoglycans in human plasma of healthy donors: Preliminary study on a small group of recruits

Glycosaminoglycans in normal human plasma, mainly represented by chondroitin sulfates and heparan sulfates/heparin (HSGAGs), show a specific distribution in the Cohn–Oncley fractions of human plasma. In the present study we investigated their effects on coagulation. Plasma was fractionated following the procedure of Cohn–Oncley, and each fraction was treated for extraction of glycosaminoglycans after extensive proteolysis; the anticoagulant activity in the extracted samples was measured by activated partial thromboplastin time (APTT). The effects of the samples containing HSGAGs on factor II and factor X activities, before and after treatment with heparinase I, were also measured. The molecular weight of HSGAGs was determined by polyacrylamide gel-electrophoresis. Cryoprecipitate and fraction I, fraction II+III, and fraction IV-1 (the fractions containing HSGAGs) prolonged the APTT, whereas fractions IV-4 and V had no effect on the APTT. Fractions containing HSGAGs showed effects on factor II and factor X activities that were sensitive to heparinase I treatment. The molecular weight of HSGAGs recovered in cryoprecipitate and fraction I was 15–18 kDa; that of HSGAGs recovered in fraction IV-1 was 12.0 kDa. In conclusion, these results demonstrate that HSGAGs of different molecular weight, endowed with anticoagulant activity, circulate in normal human plasma in association with specific proteins involved in the regulation of hemostasis; and that endogenous HSGAGs play a role in maintaining the antithrombotic/hemostatic balance in normal human plasma.

Daily Rhythmic Variations in Histamine in Human Blood

We examined whether or not normal subjects have rhythmic changes of blood histamine levels. Daily predictable variations are present with 3 maxima and 3 minima and acrophase at 09.13. The significance of these changes is presently unknown.

Cytochemical detection of histamine in the human granulopoietic series of healthy subjects and of patients affected by chronic myeloid leukaemia. A spectrophotofluorimetric test for checking OPT-induced fluorescence in isolated cells

SynopsisCellular histamine in blood and bone marrow has been identified histochemically using ano-phthaldialdehyde fluorescence reaction. The specificity of the reaction was tested by a spectrofluorometric analysis of cell extracts. In normal blood, the basophils emit a bright yellow fluorescence, whereas neutrophils, eosinophils and platelets react less consistently and when they do, they give off a less intense yellow or blue emission. In normal marrow, basophils react strongly whereas the metamyelocytes and later granular cells show only a weak yellow or blue fluorescence. In chronic myeloid leukaemia, cells of the granular series emit a strong yellow fluorescence at all stages of development, although still less intense than the basophils. During remission, the fluorescence pattern of cells from leukaemic subjects reverts to that of normal cells.

Circadian Patterns in Histamine Concentrations and Mast Cell Number in the Rat Thyroid Gland

We carried out a cross-sectional chronobiological investigation on blood histamine, thyroid histamine and thyroid mast cell number in Wistar rats. Daily, blood histamine varied from 0.38 +/- 0.01 (12.00 h) to 0.60 +/- 0.01 mg/g wet weight (20.00 h) and thyroid histamine from 21.2 +/- 1.19 (04.00 h) to 38.3 +/- 1.54 mg/g wet weight (08.00 h). The number of mast cells per microscopic field ranged from 10.8 +/- 0.6 (16.00 h) to 14.6 +/- 0.6 (12.00 h) in males and from 8.3 +/- 0.2 (04.00 h) to 14 +/- 0.4 (12.00 h) in females. Chronobiologic analysis indicates that the levels of all three variables follow a circadian pattern with a period of 12 h. Peak levels were noted at 07.36 h and 19.36 h for the blood histamine concentration, at 09.00 and 21.00 h for the tissue histamine concentration, and at 11.00 and 23.00 h for the mast cell number. The consistent, consecutive relationship of these data supports the hypothesis that thyroid mast cell number is conditioned by the blood histamine level and thyroid histamine concentration.