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Biomedical subjects

A Ricci

Publications and source records attributed to A Ricci.

At least 253 records · Page 14Linked to original sources
PubMed1988

Effect of ageing on the nerve fibre population of rat optic nerve.

The age-related changes in the number and density of optic nerve fibres were studied in 3-month-old (young), 12-month-old (adult), 20-month-old (senescent) and 30-month-old (aged) male Wistar rats. Two-micrometer-thick resin-embedded transverse sections of the optic nerve of animals of the different age groups were stained with toluidine blue and examined under a light microscope at low (X5) and high (X500) magnification. The optic nerve cross-sectional area and the number of nerve fibres with diameters shorter or longer than 1 micron were assessed by means of computerized image analysis. Optic nerve cross-sectional area is constant in young and adult rats, but is increased in senescence. The number of optic nerve fibres with a diameter less than 1 micron is decreased by about 18 and 12% in 20-month-old rats versus 3- and 12-month-old rats, respectively. The number of these nerve fibres is decreased by about 43, 39 and 30% in 30-month-old rats versus 3-, 12- and 20-month-old animals, respectively. In contrast no age-dependent changes were observed in nerve fibres with diameters greater than 1 micron. The present data suggest that age-related impairment of nerve cell population described by other authors in rat retina and visual cortex occurs also at the level of the optic nerve.

Aging↗
PubMed1988

[New heterocyclic derivatives of benzimidazole with germicidal activity. V. Synthesis and activity of new derivatives of di-2-benzimidazolyl-2,5-furan].

In continuation of the research in the field of germicidal and antimycotic agents, the synthesis of 14 new derivatives of di-2-benzimidazolyl-2,5-furan is described. These derivatives are differently substituted (R not equal to R') in the position 5 of the two benzene rings. These new compounds showed no germicidal or fungicidal activity, when tested on different cultures. New compounds are under investigation.

Anti-Infective Agents↗
PubMed1988

Atypical fibroxanthoma. A study of 14 cases emphasizing the presence of Langerhans' histiocytes with implications for differential diagnosis by antibody panels.

Fourteen consecutive cases of atypical fibroxanthoma (AFX) seen during a 4-year period were studied histologically; of these, 12 were further examined for the presence of immunocytochemically detectable cytokeratin (CK), vimentin (VIM), S-100 protein, melanocyte-associated antigen (MAA), muscle-specific actin (MSA), alpha-1-antitrypsin (A1AT), alpha-1-antichymotrypsin (A1ACT), and ferritin (FER). In four cases, electron microscopy was also performed. Tumor cells were nonreactive with antibodies directed against CK and MAA, strongly reactive with anti-VIM, and variably reactive with A1AT, A1ACT, MSA, and FER. Our findings are consistent with the current notion that these tumors are "fibrohistiocytic". However, in 11 of 12 cases studied, a subpopulation of cells with features of Langerhans' histiocytes (LH) was also identified. These were dendritic cells within the substance of the tumor that were strongly reactive with S-100 antibody and uniformally nonreactive with MAA antibody; ultrastructurally, they were seen to contain typical Birbeck granules. LH characteristically comprised no more than 5% of the overall cell population of the tumor; however, in restricted portions of some lesions, they sometimes accounted for up to 80% of tumor cells. The occurrence of LH in AFX, although previously reported, has not generally been emphasized. Awareness of their presence as an expected and sometimes extensive component of AFX can be important when interpreting differential immunocytochemical panels applied to malignant spindle cell tumors of skin.

Adult↗
PubMed1987

[Mechanisms of regulation of arterial blood pressure: role of the sympathetic nervous system and of the renin-angiotensin system in patients on a low-sodium diet].

In order to discover more about the role of the sympathetic nervous and renin-angiotensin systems in the preservation of homeostasis during chronic reductions of salt intake, blood pressure, blood catecholamines and renin activity were measured in a group of healthy subjects in normal conditions and on a salt-free diet combined with blockade of the conversion enzyme by enalapril. The results confirmed the hypothesis advanced on an earlier occasion i.e. that both hormone systems contribute to pressure during salt depletion in the initial phase, while over the long term only the renin-angiotensin system is activated though when this is inhibited, the sympathetic nervous system will take over its function.

Adolescent↗
PubMed1987

A clinicopathologic and immunohistochemical study of 16 patients with small intestinal leiomyosarcoma. Limited utility of immunophenotyping.

Clinicopathologic data including immunophenotypic expression of 16 new cases of small intestinal leiomyosarcoma are presented. Patient age ranged from 27 to 87 years (mean, 61 years) with a 2.2:1 male-female ratio. Eighty-eight percent of tumors occurred distally, i.e., in the jejunoileum. Considerable histologic heterogeneity was noted including epithelioid, myxoid, and sclerotic variants. Stratification by histologic grade suggests important clinical subsets. Only in grade I tumors is surgical extirpation alone potentially curative. Grade II tumors are associated with meaningful survival usually measured in years, however, nearly all patients can be expected to die from their tumors. Grade III sarcomas are fully malignant and rapidly progressive: except for one case with limited follow-up, all patients with Grade III sarcomas died of disease with a mean survival of only nine months (median, 2 months). Immunostaining with antibodies directed against vimentin, muscle-specific actin, desmin, and S-100 protein were performed. Only antivimentin was uniformly reactive. Sixty-three percent of cases tested showed actin immunoreactivity, and no tumors revealed immunohistochemically detectable desmin or S-100 protein. Although many small bowel stromal sarcomas appear "poorly differentiated" by immunohistochemical methods presently available, that they are indeed leiomyosarcomas seems most likely from their intramural location and light histologic study. The limited utility of immunophenotyping and the importance of histologic grading are stressed.

Actins↗
PubMed1987

Metabolism of coronary vasculature in senescent rats--a histochemical study.

The effect of senescence on the metabolic profile of rat coronary arteries and arterioles was studied using enzyme histochemical techniques. In coronary arteries anaerobic metabolism predominates. In senescence an increase of adenosine triphosphatase (ATPase) occurred. The succinate dehydrogenase (SDH) and the respiratory chain metabolism marker NADH2-tetrazolium reductase (NADHD) showed an age-related decrease. Lactate dehydrogenase was unchanged. In the coronary arterioles, on the contrary, aerobic metabolism dominates. In senescence a significant decrease of NADHD and a moderate reduction of SDH and ATPase was observed. L-Carnitine administration significantly stimulated some enzymatic activities related to aerobic metabolism primarily at the arteriolar level.

Adenosine Triphosphatases↗
PubMed1987

New heterocyclic derivatives of benzimidazole with germicidal activity. IV--In vivo anticandida activity of 5-fluoro-2-(5'-nitro-2'-furyl) benzimidazole (F-O-NO2).

We have studied the possible in vitro and in vivo antibacterial activity of 5-fluoro-2-(5'-nitro-2'-furyl)benzimidazole (F-O-NO2). Our data demonstrate that F-O-NO2 is able to inhibit the in vitro growth of different mycetes and bacteria, including Candida albicans and Cryptococcus neoformans. We also tested the possible in vivo activity against Candida albicans. The results clearly show that treatment with F-O-NO2 is able to significantly augment the survival of all treated animals; in particular, when injected i.p. at the dose of 120 mg/kg, 30' or 1 hr after Candida albicans challenge, it givens a MST (Medium Survival Time) longer than 60 days. These data demonstrate that F-O-NO2 has antibacterial and antimycotic activity.

Animals↗