Biomedical subjects

A Ricci

Publications and source records attributed to A Ricci.

At least 217 records · Page 12Linked to original sources

PubMed1991

Intrinsic innervation of the rat knee joint articular capsule and ligaments.

In spite of the practical importance of having a detailed knowledge of knee joint innervation to understand the pathophysiologic aspects, little information is now available concerning the density and pattern of the nerve fibres which are distributed to it. The present study has been designed to investigate the density and distribution of nerve fibres and receptor corpuscles in the knee joint articular capsule, cruciate and collateral ligaments in the rat, using the acetylcholinesterase (AChE) histochemical in toto staining technique. The investigation was performed on male Wistar rats of 3 months of age, some of which had been treated with capsaicin to deplete their afferent 'C' fibres of their content of neuropeptides. AChE-positive nerve fibres and different types of receptor corpuscle endings were found within articular capsule and ligaments. The highest density of AChE-positive nerve fibres was noticeable in the fibular collateral ligament followed by the tibial collateral ligament, the posterior cruciate ligament, the anterior cruciate ligament and the articular capsule. In the articular capsule the number of type I endings was higher than in the ligaments. The opposite is true for the other type of receptor corpuscles found as well as for nerve endings. Capsaicin treatment significantly reduced the density of AChE-positive nerve fibres in knee joint ligaments but did not affect nerve fibres in the articular capsule. Moreover, it caused the disappearance of some kind of receptor corpuscles within the collateral and cruciate ligaments. The above data collectively suggest that the AChE in toto staining technique may represent a good method for investigating joint innervation and that a significant percentage of nerve fibres supplying knee joint ligaments is represented by C fibre afferents.

Acetylcholinesterase↗

PubMed1991

Renal dopamine and changes in dopamine receptor ligand binding during high sodium intake.

This study was designed to measure changes in plasma levels of atrial natriuretic peptides (ANP), urine volume (UV), urinary excretion of dopamine (UDAV) and sodium (UNaV), and dopamine (DA) receptor affinity (Kd) and binding sites (Bmax) in kidneys of rats drinking normal saline for a period of 7 days. The saline intake significantly increased UV, UNaV, plasma ANP, UDAV, and its primary metabolite dihydroxyphenyl acetic acid (DOPAC) for the period of 7 days. Bmax increased significantly 1 day after the initiation of saline intake, however, the increase appeared to be transient since measurements of Bmax made after 7 days of saline intake were not significantly different from the control group. No changes in Kd were observed. These results indicate that renal DA contributes to maintenance of Na balance during increased Na intake and that renal DA receptors undergo transient changes during this period.

Animals↗

PubMed1991

Estrogen and progesterone receptors in primary eccrine carcinoma.

Primary eccrine carcinoma and metastatic mammary duct carcinoma are histologically similar and histogenetically related neoplasms that may on occasion be mistaken for one another. Mammary duct carcinomas, in primary or metastatic sites, will often express estrogen and progesterone receptors (ER and PR), and these may be detected by either biochemical or immunocytochemical methods. The expression of ER and PR in primary eccrine carcinoma, however, has not been studied. Three eccrine carcinomas were probed with antibodies to ER and PR. Immunoreactivity for hormone receptors was identified in all three cases. The recognition of this immunophenotype may be important in avoiding misdiagnosing receptor-positive eccrine carcinoma as metastatic breast cancer.

Aged↗

PubMed1991

Evaluation of pentisomide on stable ventricular premature beats. Comparison with placebo.

Pentisomide, a new class I anti-arrhythmic drug, was compared to placebo in 50 hospitalized patients with frequent (greater than 30 h-1) and stable ventricular premature beats (VPB) (variation less than 50% between two preliminary and one placebo 24-h Holter recordings). All patients underwent a single-dose acute oral testing followed by a short-term testing with 300 mg t.i.d. for 4 days and then by a 4-day placebo period. For the studied population, a 56.4% reduction of simple VPB and a 98.8% decrease of couplets and runs were the minimum required to define the drug efficacy and to exclude spontaneous variability, using the linear regression analysis. Pentisomide was found effective in 27 (54%) of the 50 patients after the acute test and in 23 (46%) after the short-term test. The drug induced a mild increase of PR and QRS intervals, while QTc, heart rate, blood pressure and ejection fraction showed no significant variations. Subjective tolerability was excellent.

Adult↗

PubMed1991

Comparative fluorometric study of benzo(a)pyrene and aza-aromatic hydrocarbon penetration and metabolism kinetics in the skin of hairless mice.

The kinetics of penetration and metabolism of BaP, BACs, DB(a,h)ACs and DB(c,g)Cs in the skin of hairless mice was studied. The relative fluorescence intensities were measured during three hours after applying 10 nmoles of the compound to the interscapular region of the mice. By using a kinetical model which combines a non-steady diffusion of a hydrocarbon through the stratum corneum and the metabolic oxidation by epidermal cells, the rate constants for the two processes were calculated. It has been shown that B(a)AC, B(c)AC and 12-MB(a)AC penetrate into the skin and are oxidized by epidermal cells more efficiently than BaP. In contrast, alkyl-DB(a,h)ACs (except 14-MDB(a,h)AC) show a great stability in the mouse skin. The carcinogenic BaP, 7-MB(c)AC and DB(a,h)AC have average rates of elimination from the skin.

Animals↗

PubMed1991

New heterocyclic derivatives of benzimidazole with germicidal activity--IX--HPLC detection of 5-fluoro-2-(5'-nitro-2'-furyl)benzimidazole (F-O-NO2) in biological samples.

The HPLC technique for the isolation and quantitation of 5-fluoro-2-(5'-nitro-2'-furyl)benzimidazole (F-O-NO2), previously described by the same Authors, in biological samples from mice is reported. Evidence is given that the highest biological concentration and the time needed for reaching it depend both on the dose and on the administration route. In fact, almost the same maximal biological concentration of F-O-NO2 (about 0.18 micrograms/mouse) is reached after 60 min from either 40 mg/Kg IP or 200 mg/Kg os drug administration, whereas the maximal biological concentration of F-O-NO2 (5.75 micrograms/mouse) is reached after 30 min from 120 mg/Kg IP drug administration.

Animals↗

PubMed1991

Cytoplasmic vacuolization of enterocytes: an unusual histopathologic finding in juvenile nutritional megaloblastic anemia.

We report a case of juvenile nutritional megaloblastic anemia with emphasis on the histologic findings in the upper gastrointestinal system, including the previously unreported feature of periodic acid-Schiff (PAS)-negative, Alcian blue-negative cytoplasmic vacuoles (CV) in duodenal enterocytes. These CV were reminiscent of those described in abetalipoproteinemia; however, the patient's lipid profile was normal. All histopathologic changes in the upper gastrointestinal tract (with the exception of mild reflux esophagitis) reverted to normal following parenteral administration of vitamin B12. This case supports the notion that CV in enterocytes are a component (albeit a rare one) of the histopathology in cobalamin deficiency.

Anemia, Megaloblastic↗

PubMed1990

The noradrenergic innervation of the ovary in old rats.

The influence of ageing on the noradrenergic innervation of the ovary was studied in female Wistar rats using high pressure liquid chromatography (HPLC) with electrochemical detection and catecholamine histofluorescence techniques. Old age was accompanied by a significant decrease in ovarian noradrenaline levels. In young animals (3-month-old) noradrenergic nerve fibres were distributed primarily to blood vessels and in lesser amounts to the interstitial glands. In aged animals (24-month-old) perivascular noradrenergic fibres were reduced by more than 40%; interstitial gland nerve fibres were reduced by approximately 20%. The possibility that impaired noradrenergic ovarian innervation occurring in old age may be in some way related with age-dependent failure in reproductive activity is discussed.

Aging↗

PubMed1990

Age-related changes of dopamine sensitive cyclic AMP generation in the rat frontal cortex.

The dopamine (DA) D-1 and D-2 receptors coupled to 3',5'-cyclic adenosine monophosphate (cAMP) generation were studied in membrane particles of the frontal cortex in young (3-month-old), adult (12-month-old) and aged (24-month-old) male Sprague-Dawley rats. Activation of D-1 receptors with DA, apomorphine or fenoldopam enhanced accumulation of cAMP in the frontal cortex of young rats. The stimulatory effect elicited by DA on cAMP generation declined by about 20% in adult rats. No further decline in cAMP accumulation was noticeable in aged animals. The response to dopaminergic agonists was blocked by the D-1 receptor antagonist SCH 29390 in the three age groups examined. The presence of D-2 receptors, negatively coupled to cAMP generation, was demonstrated by incubating frontal cortex membrane particles with SCH 23390 and then with DA. This inhibitory response, was also elicited with D-2 receptor agonists quinpirole or bromocriptine in the absence of SCH 23390 in which these compounds produced a decrease in cAMP. The decrease in cAMP caused following D-2 receptor stimulation was shown to be enhanced with age. No difference was observed between the three age groups of animals in the activation of cAMP production by forskolin. The present data suggest a selective decrease in the coupling between the D-1 receptor and cAMP generation in the frontal cortex of adult and aged rats and of an age-dependent increase in the coupling between the D-2 receptor and cAMP inhibition. The functional consequences of these biochemical changes may have important implications in the aging of the rat frontal cortex.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

PubMed1990

Age-related changes in adrenaline content of rat splanchnic blood vessels.

The influence of ageing on the adrenaline content of the superior mesenteric artery and vein, renal artery and vein and portal vein was studied in 3-month- (young), 12-month- (adult) and 24-month-old (old) male Wistar rats using radioenzymatic assay for the measurement of catecholamine levels. Adrenaline concentrations were unchanged in the vascular wall of the blood vessels examined in adult rats, but were significantly decreased in the vascular wall of the superior mesenteric, renal and portal veins of old rats. In contrast, no age-dependent changes of adrenaline levels were found in the vascular wall of the superior mesenteric or renal arteries. The possibility that the loss of adrenaline concentrations in the venous vascular wall may be in some way related to the cardiovascular impairment occurring with age is discussed.

Aging↗

PubMed1990

Demonstration of dopamine DA-1 receptor sites in rat juxtaglomerular cells by light microscope autoradiography.

The binding of the selective DA-1 receptor antagonist [3H]-SCH 23390 in sections of rat kidney was studied using combined in vitro biochemical radio-receptor assay and autoradiography. [3H]-SCH 23390 was bound to sections of rat kidney in a manner consistent with the labeling of DA-1 receptors with a dissociation constant value of 4.2 nmol/l and a Bmax value of 180.6 fmol/mg protein. Light microscope autoradiography revealed a dense accumulation of silver grains in juxtaglomerular cells and in proximal convoluted tubule cells. These findings suggest that the stimulation of renin release elicited by dopamine and DA-1 receptor agonists may be mediated by the activation of DA-1 receptors located on juxtaglomerular cells.

Animals↗

PubMed1990

Age-dependent changes of the sympathetic innervation of the rat kidney.

The influence of aging on the sympathetic innervation of the kidney was studied in 3- (considered to be young), 12- (considered to be adult) and 24- (considered to be old) month-old male Sprague-Dawley rats by means of high pressure liquid chromatography with electrochemical detection, catecholamine histofluorescence and acetylcholinesterase (AChE) histochemistry. Body and kidney weights were significantly increased in adult in comparison with young rats. No further increase of either body or kidney weight was appreciated in old rats. Noradrenaline levels were increased by about 48% in adult rats and were decreased in old rats (by approx. 22% vs. young and 60% vs. adult). The density of perivascular noradrenergic fibres was significantly increased in adult rats and decreased in old animals. The percentage of kidney glomeruli supplied by AChE-positive nerve fibres is also remarkably increased in 12-month old rats and decreased in 24-month-old rats. The present data indicate that there is a striking increase in the expression of sympathetic innervation of rat kidney at 12 months of age followed by a significant decrease in the expression of innervation in old age. These changes are discussed in relation to the age-dependent impairment of renal function.

Acetylcholinesterase↗

PubMed1990

Prediction of cardiac events after uncomplicated myocardial infarction by cross-sectional echocardiography during transesophageal atrial pacing.

Atrial pacing can safely be utilized shortly after myocardial infarction. To evaluate the prognostic value of wall motion abnormalities induced by such pacing 83 consecutive patients with recent uncomplicated myocardial infarction underwent transthoracic cross-sectional echocardiography during transesophageal atrial pacing and upright bicycle exercise stress test. Patients were followed-up for 14 +/- 5 months. During the atrial pacing and the echocardiography, patients were defined at high risk if abnormalities of wall motion were detected in left ventricular regions remote from the infarcted area. Then, during the exercise stress test, high risk patients were those with ST segment depression greater than or equal to 1 mm. On the other hand, patients were considered to be at low risk if they had no abnormalities of wall motion during atrial pacing in remote regions or, in the case of the stress test, if they did not develop ST depression greater than or equal to 1 mm. Of the 83 patients, 21 had major cardiac events during the period of follow-up. Cardiac events occurred in 15/23 (65%) and 5/60 (8%, P less than 0.001) patients assigned to the groups adjudged to be at high and low risk, respectively, on the basis of echocardiographic results. Exercise testing was less reliable in identifying patients at risk of future cardiac events. Major events occurred in only 6 of the 19 patients with a positive stress test (32%, P less than 0.05 vs positive stress echocardiography) and in 14 of the 64 patients with a negative exercise stress test (22%, P = NS vs positive exercise stress test, P less than 0.05 vs negative atrial pacing echocardiography).

Cardiac Pacing, Artificial↗

PubMed1990

Dopamine modulation of pathological human chromaffin tissue.

To evaluate the presence of dopamine-2(DA2) binding sites in pheochromocytoma tissue, we performed binding studies and light microscopy autoradiography on sections of 7 different tumors. 3-H-Spiroperidol, a DA2 ligand, bound specifically to tumor sections with a (mean +/- SD) Kd value of 1.93 +/- 0.62 nmol/L. Binding site density (Bmax) was 29.16 +/- 2.33 fmol/mg tissue. Light microscopy autoradiography showed a nonhomogenous localization of silver grains within chromaffin cells. The specific binding was about 50% of total. To investigate whether DA2 binding sites found on pheochromocytoma cells might modulate catecholamine (CA) release, we studied the effects of oral bromocriptine (2.5 mg) on circulating CA of 5 patients with pheochromocytoma. In these patients bromocriptine caused a decrease in blood pressure (P less than .05) but no significant change in plasma CA. Our study shows the presence of DA2 binding sites on tumoral chromaffin tissue. As bromocriptine, a DA2 receptor agonist, was not able to modify tumor CA secretion, the functional role, if any, played by these binding sites on tumor secretion is still to be clarified.

Adrenal Gland Neoplasms↗

PubMed1990

Autoradiographic localization of vascular dopamine receptors.

By using combined in vitro radioreceptor binding and autoradiographic techniques, the pharmacological profile and the anatomical localization of dopamine-1 (DA-1) and dopamine-2 (DA-2) receptors were assessed in rat cerebral, mesenteric and renal arteries. 3H-SCH 23390 (DA-1 ligand) was bound by the medial layer of cerebral, mesenteric and renal arteries without different density in large, medium and small sized arteries. Moreover, 3H-SCH 23390 binding sites were not sensitive to chemical sympathectomy, suggesting postjunctional localization of DA-1 receptors. 3H-Spiroperidol (DA-2 ligand) was bound primarily by the adventitial, the adventitial-medial border as well as by the intimal layer of cerebral, mesenteric and renal arteries. The accumulation of adventitial and adventitial-medial 3H-spiroperidol binding sites was higher in medium and small sized arteries than in large ones and was remarkably reduced after chemical sympathectomy. These results show prejunctional localization of DA-2 receptors and further suggest that some DA-2 binding sites are located in the arterial intima.

Animals↗

PubMed1990

Autoradiographic localization of dopamine DA-1 receptors in the rat renal vasculature using [3H]-SCH 23390 as a ligand.

1. The localization of the selective dopamine (DA) DA-1 receptor antagonist [3H]-SCH 23390 was studied in sections of rat kidney using combined radioreceptor binding and autoradiographic techniques to identify the target of DA-1 receptors in renal vasculature. 2. Binding data were consistent with the labelling by [3H]-SCH 23390 of a single population of high affinity DA-1 sites. The apparent dissociation constant value (Kd) was 4.2 nM and the maximum binding capacity value (Bmax) was 140.6 +/- 6.5 fmol mg-1 tissue. Selective DA-1 or mixed DA-1 and DA-2 receptor antagonists or agonists were able to antagonize dose-dependently [3H]-SCH 23390 binding to sections of rat kidney. DA-2 receptor selective antagonists were ineffective. 3. Light microscope autoradiography using sections exposed to nuclear emulsion for 2 weeks revealed development of specific silver grains only within proximal cortical tubules. Longer exposure times (10 weeks) caused the development of specific silver grains in proximal and distal cortical tubules and in the medial layer of intrarenal arteries. 4. Quantitative analysis of the density of silver grains within the cortical tubules and the medial layer of intrarenal arteries revealed a significantly higher density of binding sites in proximal cortical tubules than in the vasculature or in distal cortical tubules. No significant differences in the density of silver grains in the medial layer of interlobar arcuate or cortical radial arteries were observed. 5. These results suggest that, using adequate ligand concentrations and exposure times for autoradiography, both tubular and vascular DA-1 receptors can be visualized in the rat kidney. The observation of a higher density of proximal tubules DA-1 receptors is consistent with the hypothesis of a more important role of DA-1 receptors in the control of natriuresis than of renal haemodynamics.

Animals↗

PubMed1990

The renal dopaminergic system in ageing.

1. The kidney contains rather large stores of dopamine (DA) (both neuronal and non-neuronal) and is rich in DA-1 and DA-2 receptors. However, no information is so far available as to the age-related changes of the renal dopaminergic system. 2. DA-1 receptors were studied in the kidney of young (3-month-old), adult (12-month-old) and aged (27-month-old) male Wistar rats using radioreceptor binding and autoradiographic techniques. [3H]-SCH 23390 was used as a ligand. 3. Binding studies demonstrated a significant loss in the density but not in the affinity of [3H]-SCH 23390 binding in sections of kidney of adult animals in comparison with young animals. A further decrease in the density of DA-1 binding sites was noticeable in aged rats in comparison with adult rats. 4. Autoradiography revealed that in the kidney [3H]-SCH 23390 binding sites are located primarily within the proximal cortical tubules and, in lesser amount, within the distal cortical tubules and the smooth muscle of the intrarenal arteries. Ageing is accompanied by a more remarkable loss of tubular than vascular DA-1 receptors. 5. These findings suggest that the renal DA-1 receptor system is impaired with age similarly as described for the striatal D-1 receptor system.

Aging↗

PubMed1990

Absence of right-left asymmetries in the rat hippocampus as demonstrated by Timm staining.

Although biochemical and behavioural studies have shown right-left differences in several areas of the rat limbic system, some anatomical studies reported no significant right-left differences in several morphological parameters of the hippocampus. The purpose of the present study was to determine whether there are asymmetries in the micro-anatomy of the rat hippocampus by examining the intensity of Timm staining in various hippocampal fields and the area occupied by mossy fibres by the use of combined microdensitometric and quantitative image analysis techniques. Timm staining demonstrates the distribution of intrahippocampal association pathways because it is a histochemical marker of zinc and other heavy transition metals. There were no right-left differences in the density of Timm staining at the level of the dentate gyrus, in the dendritic layer of CA1 and CA2 fields, in the mossy fibre area or in the subiculum. These findings provide further evidence of a lack of morphological asymmetry in the rat hippocampus.

Animals↗