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Biomedical subjects

G Rossi

Publications and source records attributed to G Rossi.

At least 487 records · Page 27Linked to original sources
PubMed1992

Development of a Langerhans cell phenotype from peripheral blood monocytes.

Epidermal Langerhans cells (ELC) are definitively primed to differentiate into dendritic cells (DC). It is unknown at what stage of monocyte development this priming occurs. In a culture system characterized by low paracrine stimulation, i.e. Iscove's modified Dulbecco medium (IMDM) with 2% FCS, we tested the ability of peripheral blood monocytes to turn to the route of the LC-DC lineage. In this system monocytes did not develop significant yeast cell phagocytosis, although mannose receptors were available. However, they became strong stimulators of mannan specific T cell proliferation. Phenotype development was analysed by flow cytometry using the monoclonal antibodies OKT6 (CD1a), IOT2 (HLA-DR), IOM2 (CD14) and the ligand Man-BSA-FITC. CD1a was the first marker which distinguished cultured monocytes from developing macrophages, obtained by addition of 8% human serum. Like cord blood Langerhans cells (CBLC) they internalized OKT6 in deep coated pits. They maintained a phenotype of monocyte derived Langerhans cells (MoLC) during eight days of in vitro culture, expressing CD1a, mannose receptors and HLA-DR and decreasing CD14, if left in their own conditioned medium. MoLC could be converted into macrophages by addition of human serum only within the first four days in vitro. Our data suggest that monocytes acquire an LC phenotype by autocrine stimulation.

Antigens, CD↗
PubMed1992

Aggressive treatment of intrathoracic recurrences of thymoma.

Between 1974 and 1988, 21 patients with intrathoracic recurrences of thymoma received radiotherapy with radical intent; surgery was always attempted when considered feasible: 11 patients were partially (6 cases) or totally (5 cases) resected before irradiation, while in the other 10 radiotherapy was the only treatment. In 7 cases the recurrence was confined to the anterior mediastinum, 9 had pleural nodules without mediastinal lesions and 5 had both mediastinal and pleural lesions. Mediastinal recurrences were treated by opposed parallel mediastinal fields with 2/3 of the dose delivered through the anterior port: doses ranged between 38 and 44 Gy; a boost of 10-16 Gy was given in patients not radically resected. Pleural nodules were treated with a variety of techniques according to the extent of the lesions. The 7-year survival of the whole group was 70%; 5 patients died: 4 with intrathoracic progression and one with distant metastases. The survival was 74% in the 11 patients having received surgery, either radical or subtotal, and 65% in the 10 patients treated with radiotherapy alone: the difference is not significant. Patients with Karnofsky index greater than 70 had a significantly better survival (100%, versus 28%, p = 0.0015). This is a selected series of patients presenting recurrences still amenable to a radical treatment either by surgery and radiotherapy or by radiotherapy alone: the results confirm that an aggressive approach is warranted in patients in good general conditions with recurrences confined to the mediastinum and/or 1 hemithorax.

Adult↗
PubMed1992

Abnormal growth hormone and cortisol, but not thyroid-stimulating hormone, responses to an intravenous glucose tolerance test in normal-weight, bulimic women.

Abnormal growth hormone (GH) and adrenocorticotropic hormone (ACTH)/cortisol secretory patterns in response to a glucose load have been observed in underweight anorectic women. The present study was performed in an attempt to establish whether changes in the hypothalamic/pituitary sensitivity to hyperglycemia occur in bulimia in the absence of weight disturbance. Therefore, serum GH, plasma cortisol, and plasma insulin concentrations were measured in eight women with normal weight bulimia and in eight normal women during an intravenous glucose (0.33 g/kg as an IV bolus) tolerance test (IGTT). In addition, since abnormal pituitary hormone responses to a glucose load might reflect alterations in somatostatin (SRIH) release, TSH secretion also was measured, in view of its sensitivity to SRIH inhibition. Both GH and cortisol levels progressively and significantly declined during IGTT in the normal subjects. In the bulimic women, cortisol levels remained unchanged, whereas GH concentrations rose significantly after glucose injection. Plasma cortisol and serum GH levels were significantly higher in the bulimic than in the control subjects. No significant differences between groups were observed in hyperglycemia-induced insulin increments or in TSH decrements. These data indicate that an altered sensitivity to hyperglycemia affects the hypothalamic/pituitary centers controlling the secretion of the counterregulatory hormones GH and ACTH/cortisol in bulimia nervosa. The lack of a simultaneous change in the TSH secretory pattern argues against a possible involvement of SRIH in the pathophysiology of this disorder.

Adult↗
PubMed1992

Different effects of baclofen on LH and cortisol responses to naloxone in normal men.

The possible involvement of GABAergic B receptors in the control of LH and ACTH/cortisol secretion in response to naloxone was evaluated in seven normal men. Subjects were tested with naloxone (4 mg IV bolus plus 10 mg infused over 2 hr) with or without previous treatment with the gamma-aminobutyric acid (GABA)-ergic B receptor agonist, baclofen (5, 10 or 15 mg PO 30 min before naloxone). In additional experiments, six normal men were tested with 15 mg baclofen or placebo 30 min before a 2-hr infusion of normal saline. Plasma cortisol levels rose 70% in response to naloxone. The naloxone-induced cortisol rise was not modified by pretreatment with baclofen (5, 10 or 15 mg). Plasma LH concentrations rose 66% in response to naloxone. When the lowest dose of baclofen (5 mg) was administered, the LH response to naloxone remained unchanged. In contrast, 10 mg baclofen produced a significant reduction, and 15 mg baclofen completely abolished the naloxone-induced LH rise. The administration of baclofen or placebo alone did not change basal plasma levels of cortisol and LH. These data suggest that, in normal men, GABA B receptors participate in the endogenous opioidergic control of LH secretion, but not of ACTH/cortisol secretion.

Adrenocorticotropic Hormone↗
PubMed1992

Influence of basal androgen levels in euandrogenic women on glucose homeostasis.

OBJECTIVE: To evaluate possible relationships between insulin action and the normal variations of serum androgens in euandrogenic women. DESIGN: Prospective evaluation of insulin action in normal nonobese women using hyperglycemic and euglycemic hyperinsulinemic clamp techniques, correlating insulin action to serum testosterone (T), free T, androstenedione (A), and dehydroepiandrosterone sulfate (DHEAS). Statistical analysis used Spearman's rank correlation. SETTING: Yale University Clinical Research Center. PARTICIPANTS: Nonobese females with normal oral glucose tolerance tests, on no medications known to affect glucose metabolism, having the following range of serum androgen levels: T, 0.69 to 3.12 nmol/L; free T, 0.17 to 1.25 nmol/L; A, 2.48 to 11.31 nmol/L; DHEAS, 0.68 to 10.61 mumol/L. Total number of patients studied: hyperglycemic clamps, n = 58; euglycemic hyperinsulinemic clamps, n = 43. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Pancreatic insulin secretion in response to hyperglycemia and insulin action as assessed by insulin-mediated glucose utilization using the euglycemic, hyperinsulinemic clamp technique. RESULTS: We identified no significant correlation between serum androgens and either glucose uptake or insulin-mediated glucose utilization. Glucose-stimulated insulin release was negatively correlated with serum T and free T throughout the normal range of these hormones. CONCLUSION: We conclude that, within the normal range, variations of serum androgens are not correlated with changes in the response to insulin. It seems unlikely, therefore, that modest increases of serum androgens within the normal range are responsible for inducing insulin resistance.

Androgens↗
PubMed1992

Differences in left ventricular structural and functional changes between pheochromocytoma and essential hypertension. Role of elevated circulating catecholamines.

Experimental findings suggest that catecholamines increase protein synthesis and play a role in cardiac hypertrophy. We hypothesize that elevated circulating plasma catecholamines in pheochromocytoma influence cardiac structural and functional remodeling. We compared 15 patients with surgically proven pheochromocytoma and 15 with untreated essential hypertension; we matched the patients for age, sex, body surface area, and blood pressure (BP) levels. Left ventricular hypertrophy (LVH) was identified by M-mode echocardiography in six patients with pheochromocytoma and in four with essential hypertension. Among both groups there were no differences in cardiac structure, no correlation between left ventricular mass and BP, no significant differences in mitral E-F slope, no correlation between either plasma norepinephrine or plasma epinephrine levels, and no differences in the left ventricular structural indices measured. In the pheochromocytoma group, left ventricular end systolic stress and end systolic diameter were significantly lower and left ventricular percent fractional shortening was higher. Plasma norepinephrine levels were higher in the pheochromocytoma group, but did not differ among patients of that group with and without LVH. We conclude that in both pheochromocytoma and essential hypertension, only a subset of patients develop evidence of LVH, and that in pheochromocytoma, the elevation of circulating plasma catecholamines is not necessarily associated with LVH. These results indicate that factors other than catecholamines and BP determine the development of LVH in pheochromocytoma.

Adolescent↗
PubMed1992

Hypoglycemia-induced arginine vasopressin and oxytocin release is mediated by glucoreceptors located inside the blood-brain barrier.

Arginine vasopressin (AVP) and oxytocin (OT) responses during an insulin (0.15 IU/kg body weight) tolerance test (ITT) were evaluated in normal men while they were infused with normal saline, glucose or fructose. Insulin-induced hypoglycemia produced significant plasma AVP and OT increments in the control test. The infusion of fructose was unable to change the posterior pituitary hormonal responses to hypoglycemia. In contrast, AVP and OT responses during ITT were completely abolished when the concomitant infusion of glucose prevented insulin-induced hypoglycemia. These data exclude a direct role of hyperinsulinemia in the mechanism underlying the AVP and OT responses during ITT. Furthermore, since glucose, but not fructose, crosses the blood-brain barrier (BBB), the posterior pituitary hormone responses to hypoglycemia appear to be generated by stimulations of glucosensitive areas located inside the BBB.

Adult↗
PubMed1992

Stimulation of ACTH/cortisol by intravenously infused substance P in normal men: inhibition by sodium valproate.

The effect of synthetic substance P (SP), infused intravenously in doses of 0.5, 1 or 1.5 pmol/kg-1/min-1 over 60 min on ACTH/cortisol secretion was evaluated in 7 healthy men. SP tests and a control test with normal saline were randomly performed at weekly intervals. During tests, SP infusion did not produce untoward side effects or changes in blood pressure. Plasma ACTH and cortisol levels were not modified when normal saline or the lowest dose of SP were infused, whereas they were significantly increased in a dose-dependent fashion when higher amounts of SP were administered. Further studies were performed in another 7 healthy men to test the possible influence of GABAergic neurotransmission on the ACTH/cortisol response to SP. For this purpose, subjects were tested with SP (1.5 pmol/kg-1/min-1) alone and on a different occasion with SP after pretreatment with the GABAergic agent sodium valproate (200 mg 16, 8 and 1 h before the SP test). Again, the administration of SP induced a significant increase in plasma ACTH and cortisol levels. The pretreatment with sodium valproate completely abolished both ACTH and cortisol responses to SP. These data demonstrate for the first time in humans that the systemic infusion of SP stimulates ACTH/cortisol secretion, suggesting the involvement of a GABAergic mechanism in the regulation of the action of SP.

Adrenocorticotropic Hormone↗
PubMed1992

Effect of potentiation of cholinergic tone by pyridostigmine on the GH response to GHRH in elderly men.

The plasma GH response to GHRH (100 micrograms i.v.) was evaluated either alone or after pretreatment with pyridostigmine (120 mg orally 1 h prior to GHRH) in 9 younger men (age range: 22-39 years) and in 9 healthy elderly men (age range: 63-77 years). On a different occasion, subjects were tested with pyridostigmine alone. Basal concentrations of glucose, cortisol, androgens, estrogens, thyroid hormones and GH were similar in all subjects, whereas insulin-like growth factor was lower in elderly men. The GH response to GHRH was significantly lower in the older (mean peak was 6 times higher than baseline) than in the younger group (mean peak was 11.3 times higher than baseline). The pretreatment with pyridostigmine induced a striking increase in the GH response to GHRH in the younger subjects (mean peak was 26 times higher than baseline), whereas it produced only a slight increase in the GHRH-induced GH response in elderly men (mean peak was 8.7 times higher than baseline). When pyridostigmine was given alone, plasma GH levels rose significantly in both groups; however, the pyridostigmine-stimulated GH response was significantly higher in younger (mean peak was 6 times higher than baseline) than in older subjects (mean peak was 2.5 times higher than baseline). These data indicate that the cholinergic stimulatory regulation of GH release is reduced in elderly subjects. Since acetylcholine inhibits hypothalamic somatostatin release, the reduced cholinergic tone in elderly subjects may result in an increased somatostatinergic tone.

Adult↗
PubMed1992

Spontaneous idiopathic subclavian arteriovenous fistula: a case report.

Systemic arteriovenous (AV) fistulas are a rare but correctable cause of hyperkinetic circulation and congestive heart failure. They are generally due to catheterization procedures, surgery, trauma, or aneurysms. A case of truly spontaneous AV fistula between left subclavian artery and left innominate vein is described. This patient presented with symptoms that might clinically be mistaken for a carpal tunnel syndrome. The discovery of a continuous to-and-fro murmur on her left upper sternal border led to the correct diagnosis. Surgical ligature of the fistula provided complete relief of the woman's symptoms.

Angiography↗
PubMed1992

Acute hepatitis induced by cyclofenil: a case report.

The case of a 47-year old woman suffering from acute hepatitis caused by cyclofenil, a drug proposed for the treatment of anovulation and scleroderma, is presented. Hepatitis developed seven weeks after the beginning of administration of the drug and its course was reversible after withdrawal. The case is documented on the basis of liver histology and the exclusion of other causes of acute hepatitis.

Acute Disease↗
PubMed1992

[The long-term prognosis of anorexia nervosa: the evaluation of hospital treatment].

The present study is the continuation of a previous programme performed by a mail or phone questionnaire. In this study 18 subjects with anorexia nervosa were submitted to a clinical semi-structured interview, and underwent a medical examination regarding eating habits and Rorschach tests. Clinical results seemed to be quite satisfactory (none died and 84% were greatly improved or had recovered clinically) whereas the psychopathologic aspects were less positive. The authors conclude that complete clinical evaluation can be considered the only safe approach for the understanding of the clinical course.

Adolescent↗