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Biomedical subjects

C Macchi

Publications and source records attributed to C Macchi.

At least 37 records · Page 2Linked to original sources
PubMed1997

Kinking of the human internal carotid artery: a statistical study in 100 healthy subjects by echocolor Doppler.

BACKGROUND: Kinking of the internal carotid artery is a rather frequent anomaly. It is still controversial whether it has a clinical relevance, causing cerebral vascular disturbances, or if it is a mere morphologic anomaly. A study concerning its frequency in asymptomatic subjects and an evaluation of its possible correlations were, therefore, considered interesting. METHODS: The internal carotid artery was studied in 100 apparently healthy subjects (50 men and 50 women; age range: 18 to 98 years) with no history of atherosclerotic disease of the supra-aortic trunks, or diabetes mellitus, or hypertension. Each patient underwent color Doppler ultrasonography. RESULTS: In 38 subjects out of 100, and in 53 out of 200 examined arteries (100 right and 100 left arteries), a kinking was found (26.5%). In 23 kinkings (43% of all the kinkings), the maximal systolic velocity (MSV) was greater than 1 m/sec at the level of the kinking. The kinkings were more frequent in women; such prevalence was statistically significant. The frequency of kinkings was uncorrelated with the side of the artery, the age, the body weight, the height and the length of the neck. Moreover, the presence of the kinkings was not significantly correlated with the lumen of the internal carotid artery. CONCLUSIONS: Hypotheses regarding the genesis of the kinkings were discussed, and the embryogenic hypothesis was emphasized. The importance of the MSV in the diagnosis of kinkings was stressed.

Adolescent↗
PubMed1996

Further investigations on the effects of neuropeptide Y on the secretion and growth of rat adrenal zona glomerulosa.

NPY is a regulatory peptide, high levels of which are contained in adrenal glands of several mammals and which is co-released with catecholamines during various stressful conditions. The acute and chronic effects of NPY on adrenocortical secretion and growth were studied in the rat. NPY concentration-dependently increased aldosterone (ALDO), but not corticosterone (B) secretion of adrenal slices (maximal effective concentration was 10(-7) M). Two competitive inhibitors of NPY receptors, named PYX-1 and PYX-2, were found to dose-dependently inhibit ALDO response of adrenal preparations to 10(-7) M NPY; PYX-2 was more efficient than PYX-1, and at a concentration of 10(-5) M completely annulled the effect of 10(-7) M NPY. The acute bolus intraperitoneal (i.p.) injection of NPY (3 nmol/kg) raised plasma ALDO concentration (PAC), but not that of B (PBC); this effect of NPY was blocked by the simultaneous injection of PYX-2 (300 nmol/kg). The prolonged i.p. infusion with NPY (3 nmol/kg/h for 7 days) increased PAC (but not PBC) and induced a marked hypertrophy of the zona glomerulosa (ZG) and its parenchymal cells; dispersed ZG cells obtained from NPY-infused rats displayed a significantly enhanced basal and maximally agonist-stimulated ALDO production. The simultaneous infusion with PYX-2 (300 nmol/kg/h) completely annulled all these effects of NPY. The acute or chronic administration of PYX-2 alone did not evoke any apparent effect on the ZG secretion and growth. In light of these findings the following conclusions can be drawn: (i) NPY is able to stimulate not only the secretion, but also the growth of adrenal ZG in rats, via a receptor-mediated mechanism (since this effect is blocked by PYX-2); (ii) endogenous NPY does not play a prominent role in the physiological maintenance of secretion and growth of rat ZG (since PYX-2 alone is ineffective); (iii) NPY may play a crucial role in the fine tuning of the ZG functions in conditions requiring an increased release of mineralocorticoid hormones.

Aldosterone↗
PubMed1996

Effects of pneumadin (PNM) on the adrenal glands. 5. Potent stimulating action of PNM on adrenocortical growth of dexamethasone-administered rats.

Pneumadin (PNM) is a biologically active decapeptide, originally isolated from mammalian lungs, that has been previously found to acutely stimulate pituitary-adrenocortical axis in rats. The effects of 2-day PNM administration on the atrophic adrenal cortices of rats treated for 8 days with dexamethasone (DX) were investigated. PNM significantly raised adrenal weight and the average volume of adrenocortical cells. The decapeptide strikingly increased ACTH plasma concentration; however, the blood levels of aldosterone and corticosterone, as well as steroid output by adrenal quarters were not apparently affected. In light of these findings the following conclusions can be drawn: (i) PNM enhances the growth of adrenal cortex in DX-administered rats by a mechanism involving the stimulation of ACTH release; and (ii) PNM treatment is probably too short to allow DX-atrophied adrenocortical cells to re-acquire all their differentiated secretory capacities.

Adrenal Cortex↗
PubMed1996

Effects of the prolonged administration of bradykinin on the rat pituitary-adrenocortical axis.

The effects of a prolonged administration of bradykinin (BK) and/or D-Arg, [Hyp3, D-Phe7]-BK, a specific antagonist of BK receptors (BK-A) (daily subcutaneous injections of 4 nmol/rat for 6 days) on the function of the pituitary-adrenocortical axis were investigated. BK did not change plasma aldosterone concentration (PAC), but markedly lowered that of corticosterone (PBC) and consequently induced a compensatory hypersecretion of ACTH by the pituitary gland. BK-A did not apparently affect the function and growth of the adrenal gland, but, when administered together with BK, markedly raised both PAC and PBC, and provoked a significant atrophy of the adrenal gland, probably due to loss of parenchymal cells. Taken together, these rather puzzling findings do not appear to provide clear evidence for the involvement of BK in the physiological regulation of adrenocortical growth and steroidogenic capacity in rats.

Adrenal Glands↗
PubMed1996

The role of neuromedin B in the regulation of rat pituitary-adrenocortical function.

The effects of a 7-day administration of neuromedin B (NMB) and/or (Tyr4, D-Phe12)-bombesin, an NMB-receptor antagonist (NMB-A) on the function of pituitary-adrenocortical axis were investigated in the rat. NMB raised the plasma concentration of aldosterone, without affecting that of ACTH or corticosterone; the simultaneous administration of NMB-A prevented the effect of NMB. Neither NMB nor NMB-A treatments induced significant changes in adenohypophysis and adrenal weights, nor in the average volume of zona glomerulosa and zona reticularis cells. NMB-A administration lowered the volume of zona fasciculata cells, an effect annulled by the concomitant NMB administration. Our results suggest that NMB specifically stimulates aldosterone secretion, and that endogenous NMB or NMB-like peptides exert a tonic stimulating action on the growth of zona fasciculata cells.

Adrenal Cortex↗
PubMed1995

Clinical importance of the supra-isthmic anastomosis between the superior thyroid arteries in six cases of occlusion of the common carotid artery.

In six cases of occlusion of a single common carotid artery, antegrade blood flow was demonstrable in the ipsilateral internal carotid artery by doppler ultrasonography. Antegrade blood flow was also observed in the intracranial portion of the internal carotid artery, comparatively reduced and irregular with respect to that of the corresponding contralateral artery. Studies by color doppler ultrasound and digital subtraction angiography revealed the presence of a collateral arch that passed through the supra-isthmic anastomosis between the superior thyroid arteries. All six subjects examined had presented with neurological deficits that subsequently almost completely regressed. The regression of symptomatology indicates the clinical importance of the collateral circle.

Adult↗
PubMed1995

Effects of oxytocin on the function and morphology of the rat adrenal cortex: in vitro and in vivo investigations.

The effects of oxytocin (OX) on the function and morphology of the rat adrenal cortex were studied in vivo and in vitro. OX exerted a potent stimulatory action on basal, but not 10(-8) M ACTH-stimulated corticosterone (B) secretion of dispersed rat inner (zona fasciculata and zona reticularis) adrenocortical cells (maximal effective concentration: 10(-9) M); in contrast, at higher concentrations (10(-7)/10(-6) M) OX inhibited maximally ACTH-stimulated B output. A single subcutaneous (s.c.) injection of 1.2 nmol/100 g body weight OX resulted in a long-lasting (up to 12 h) rise in plasma B concentration (PBC). The prolonged administration of OX (daily s.c. injections of 0.6 or 1.2 nmol/100 g for 10 days) caused a marked lowering in the adrenal weight and volume of all adrenocortical zones, that in turn was due to a decrease in the number of their parenchymal cells; however, the average volume of inner adrenocortical cells was significantly increased. Basal PBC was lowered, but its response to ether stress was unchanged in comparison with control rats. Prolonged OX treatment did not change B secretion by adrenal slices, but it markedly raised that of dispersed inner adrenocortical cells. Our present findings clearly show that the effects of OX on the adrenal cortex depend on the experimental model employed (in vitro versus in vivo) and the duration of treatment (acute versus chronic). Taken together they allow us to conclude that OX exerts an acute direct stimulatory effect on the rat adrenal cortex, and a chronic inhibitory one, that at least in part could be due to the interference of OX with the mechanism(s) of intracellular transduction of the ACTH secretagogue signal.

Adrenal Cortex↗
PubMed1995

Effects of neuromedin-K on the rat hypothalamo-pituitary-adrenal axis.

The effects of neuromedin-K (NMK) on the rat hypothalamo-pituitary-adrenal (HPA) axis were studied both in vivo and in vitro. A subcutaneous injection of 1 nmol/100 g NMK evoked a rise in plasma ACTH level at 30 min, increased plasma corticosterone (B) concentration (PBC) at 60 and 120 min, and did not alter plasma aldosterone (ALDO) concentration (PAC). The administration of 3 nmol/100 g NMK induced a rise in plasma ACTH level at 120 min and a drop of PBC at 30 min; it increased PBC and PAC at 60 and 120 min. NMK did not affect basal B secretion of dispersed zona fasciculata/reticularis (ZF/R) cells, but markedly enhanced basal ALDO production by dispersed zona glomerulosa (ZG) cells (minimal and maximal effective concentrations were 10(-9) M and 10(-7) M). Video-imaging analysis showed that NMK (10(-8) M) increased intracellular Ca2+ concentration in dispersed ZG cells, but not in ZF/R ones. These findings indicate that NMK exerts a complex modulatory action on the rat HPA axis: low doses of NMK appear to evoke a transient stimulation of ACTH release, while high doses seem to exert a short-term inhibition of glucocorticoid synthesis followed by the compensatory hypersecretion of ACTH; moreover, elevated doses of NMK also exert a strong ALDO secretagogue action by acting directly on the ZG cells.

Adrenal Glands↗
PubMed1995

Evidence that endogenous substance-P (SP) is involved in the maintenance of the growth and steroidogenic capacity of rat adrenal zona glomerulosa.

A 7-day intraperitoneal infusion with the specific SP antagonist magnitude of D-Pro4,D-Trp7,9-SP4-11 (SP-A; 0.3 nmol.kg-1.min-1) significantly lowered plasma aldosterone (ALDO) concentration and caused atrophy of adrenal zona glomerulosa (ZG) and its parenchymal cells. Dispersed ZG cells from SP-A-infused rats displayed a marked decrease in both their basal and maximally agonist-stimulated ALDO production. The simultaneous infusion of rats with SP (0.03 nmol.kg-1.min-1) completely annulled all these effects of SP-A. The plasma levels of ACTH and corticosterone, and the morphology of adrenal zona fasciculata were not affected by SP-A or SP-A plus SP infusion. These findings suggest that endogenous SP is specifically involved in the positive control of growth and secretion of the rat ZG.

Aldosterone↗
PubMed1994

An anatomical study of the healthy human heart by echocardiography with special reference to physiological valvular regurgitation.

110 healthy subjects (45 men and 65 women ranging in age between 24 and 60 years) were studied by 2-dimensional echocardiography. In each subject the diameters of the cardiac chambers, the thickness of the intraventricular septum and posterior wall of the left ventricle in diastole, as well as the diameters and circumferences of the aortic and mitral rings were measured. Moreover, in each subject color doppler echocardiography was performed. Pulmonary valve regurgitation was observed in 47 subjects (42.7%). This finding was not correlated in a statistically significant manner to either age, sex, body weight, or height. The incidence of pulmonary regurgitation, however, tended to decrease with age. In 37 subjects (33.6%), tricuspid regurgitation was detected without any correlation to the above parameters. In 11 cases (10%), mitral regurgitation was observed; its correlation to age was statistically significant (p < 0.05). Aortic regurgitation was noted in 9 (8.2%) cases; its incidence was directly correlated to age (p < 0.01). The observed regurgitations were defined as "physiological" and precise characteristics were chosen so as to distinguish such "physiological" from "pathological" regurgitations.

Adult↗
PubMed1994

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.

Analysis of Variance↗
PubMed1991

[Advanced carcinoma of the thoracic esophagus: CT, MR, and echo-endoscopy in the staging after chemotherapy].

Thirteen patients affected with advanced epidermoid carcinoma of the thoracic esophagus were examined by means of CT, MR and endoscopic US (EUS) before and after chemotherapy. Eleven patients underwent esophagectomy and esophagogastroplasty. An intraesophageal prosthesis was positioned in 2 patients since chemotherapy had not modified tumour stage. Post-chemotherapy CT, MR and EUS parameters were compared with the corresponding pathologic findings. As for MR imaging, post-chemotherapy signal intensity variations in T1 and T2 sequences were also evaluated. MR imaging was more accurate than CT in depicting the involvement of mediastinal fatty layers, the relationships between mass and cardiovascular structures, and the cellularity. CT and MR exhibited limitations in identifying metastatic mediastinal lymph nodes, in which case EUS proved to be the most accurate technique. Both CT and MR failed to satisfactorily assess the infiltration of tracheobronchial tree, which was best demonstrated by endoscopy.

Adult↗
PubMed1987

[Staging of prostatic carcinoma. Accuracy of magnetic resonance].

Twenty-nine prostatic cancer patients were evaluated for staging purpose by Magnetic Resonance (MR). MR findings were correlated with the pathologic examination in 18/29 patients who underwent radical prostatectomy. Four MR staging parameters were evaluated individually: periprostatic fat; periprostatic venous plexus; seminal vesicles and pelvic adenopathy. MR correctly staged 16/18 patients, with one case of overstaging and one case of understaging. The diagnostic accuracy of MR in differentiating intracapsular stage B from extracapsular stage C was 87%, with a sensitivity of 90% and a specificity of 87%. MR and CT results agreed in 4 of the 7 operated patients who were examined with both techniques; in 3 cases there was disagreement, and MR was correct.

Aged↗