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Biomedical subjects

I Portioli

Publications and source records attributed to I Portioli.

At least 37 records · Page 2Linked to original sources
PubMed1993

Lymphocyte subpopulations analysis in peripheral blood in polymyalgia rheumatica/giant cell arteritis.

The phenotypic characteristics of peripheral blood lymphocytes were investigated in 22 patients suffering from active polymyalgia rheumatica/giant cell arteritis (PMR/GCA) prior to steroid treatment. We observed a significant reduction in the absolute number and the relative percentage of CD4-, CD8+ and CD3+, CD16+ and/or CD56+ cells compared to controls. Fifteen patients were investigated prospectively over a 6-month period of prednisone therapy. At the end of the study CD4-CD8+ cells had increased significantly compared to baselines, CD3+ CD16+ and/or CD56+ cells remained significantly lower when compared to controls. We did not observe any abnormalities in the absolute number and percentage of HLA-DR+ T lymphocytes, CD5+ B cells and NK cell phenotypes before or during steroid treatment. Our study confirms that there was significant increase in the absolute number of CD8+ T cells during steroid treatment in the PMR/GCA patients, but indicates the persistence of an immunological alteration despite the control of disease manifestations.

Aged↗
PubMed1993

Influence of hyperthyroidism on growth hormone secretion.

OBJECTIVE: Hyperthyroidism is associated with altered GH secretion. Whether this is due to changes of somatotroph responsiveness or reflects an alteration in negative feedback signals at the hypothalamic level is unknown. We therefore performed a series of studies to shed some light onto this issue. DESIGN: Study 1: GHRH (1 microgram/kg b.w.) was injected i.v. in 38 hyperthyroid patients and in 30 normal subjects; in 11 of the patients the GHRH test was repeated following methimazole-induced remission of hyperthyroidism. Study 2: hGH (2 U i.v.) or saline were administered 3 hours prior to GHRH; six hyperthyroid patients and six normal subjects were studied. Study 3: ten normal subjects and ten hyperthyroid patients were given 75 g oral glucose or water 30 minutes before GHRH. Study 4: 11 normal subjects and eight hyperthyroid patients were studied. TRH or vehicle were dissolved in 250 ml of saline solution and infused at a rate of 400 micrograms/h for 150 minutes. Thirty minutes after the beginning of the infusions, L-arginine (30 g infused over 45 min i.v.) was administered. PATIENTS: Hyperthyroid patients were compared to normal subjects. MEASUREMENTS: Growth hormone was measured by RIA at 15-minute intervals. RESULTS: GH responses to GHRH were subnormal in hyperthyroid patients. Following antithyroid drug treatment with methimazole, GH responses to GHRH increased in these patients in comparison to pretreatment values. Serum IGF-I levels, which were elevated before treatment, decreased after methimazole administration. Exogenous GH administration induced a clear decrease of GH responses to GHRH in both control and hyperthyroid subjects. On the other hand, oral glucose load decreased the GH responses to GHRH in normal but not in hyperthyroid subjects. TRH administration did not modify the GH responses to arginine in either normal subjects or hyperthyroid patients. CONCLUSIONS: Hyperthyroidism is associated with increased serum IGF-I levels and marked alterations in the neuroregulation of GH secretion. These changes involve decreased GH responsiveness to GHRH at the pituitary level and, at the hypothalamic level, a lack of suppressive effect of an oral glucose load. The normal inhibitory effect of exogenous GH administration but not of an oral glucose load in hyperthyroid patients suggests that these two feedback signals act through different mechanisms. The lack of effect of a TRH infusion on GH responses to L-arginine in normal and hyperthyroid patients makes an inhibitory role for TRH in GH secretion unlikely, at least in Caucasian subjects.

Adult↗
PubMed1993

Melatonin stimulates growth hormone secretion through pathways other than the growth hormone-releasing hormone.

OBJECTIVE: There is evidence that melatonin plays a role in the regulation of GH secretion. The aim of this study was to investigate the neuroendocrine mechanisms by which melatonin modulates GH secretion. Thus we assessed the effect of oral melatonin on the GH responses to GHRH administration and compared the effects of melatonin with those of pyridostigmine, a cholinergic agonist drug which is likely to suppress hypothalamic somatostatin release. DESIGN: The study consisted of four protocols carried out during the afternoon hours. Study 1: oral melatonin (10 mg) or placebo were administered 60 minutes prior to GHRH (100 micrograms i.v. bolus). Study 2: GHRH (100 micrograms i.v. bolus) or placebo were administered at 0 minutes; oral melatonin or placebo were given at 60 minutes and were followed by a second GHRH stimulus (100 micrograms i.v. bolus) at 120 minutes. Study 3: placebo; oral melatonin (10 mg); oral pyridostigmine (120 mg); melatonin (10 mg) plus pyridostigmine (120 mg) were administered on separate occasions. Study 4: placebo; oral melatonin (10 mg); oral pyridostigmine (120 mg); melatonin (10 mg) plus pyridostigmine (120 mg) were administered on separate occasions 60 minutes prior to a submaximal dose (3 micrograms i.v. bolus) of GHRH. SUBJECTS: Four groups of eight normal male subjects, ages 22-35 years, were randomly assigned to each protocol. MEASUREMENTS: Growth hormone was measured by RIA at 15-minute intervals. RESULTS: Oral melatonin administration had a weak stimulatory effect on GH basal levels. Prior melatonin administration approximately doubled the GH release induced by supramaximal (100 micrograms) or submaximal (3 micrograms) doses of GHRH. Melatonin administration restored the GH response to a second GHRH challenge, given 120 minutes after a first GHRH i.v. bolus. The GH releasing effects of pyridostigmine, either alone or followed by GHRH, were greater than those of melatonin. However, the simultaneous administration of melatonin and pyridostigmine was not followed by any further enhancement of GH release, either in the absence or in the presence of exogenous GHRH. CONCLUSIONS: Our data indicate that oral administration of melatonin to normal human males increases basal GH release and GH responsiveness to GHRH through the same pathways as pyridostigmine. Therefore it is likely that melatonin plays this facilitatory role at the hypothalamic level by inhibiting endogenous somatostatin release, although with a lower potency than pyridostigmine. The physiological role of melatonin in GH neuroregulation remains to be established.

Administration, Oral↗
PubMed1993

Evidence against depletion of the growth hormone (GH)-releasable pool in human primary hypothyroidism: studies with GH-releasing hormone, pyridostigmine, and arginine.

We investigated whether the impaired GH secretion of hypothyroid patients could be due to an increase in hypothalamic somatostatinergic tone. Twenty-four patients with primary hypothyroidism [20 females and 4 males; mean age (+/- SE), 47.5 +/- 2.7 yr] and 20 normal subjects (17 females and 3 males; age, 47.6 +/- 3.0 yr) were studied. In the first group of 12 hypothyroid patients, administration of pyridostigmine, a cholinergic agonist drug (120 mg, orally, at -60 min), notably increased GH responses to GH-releasing hormone (GHRH; 1 microgram/kg, iv, at 0 min; peak GH levels for pyridostigmine plus GHRH vs. placebo plus GHRH, 16.6 +/- 4.9 vs. 6.0 +/- 1.8 micrograms/L; P < 0.01). The GH responses to pyridostigmine plus GHRH, however, were considerably lower than those in 10 normal subjects (peak GH levels, 53.0 +/- 3.5 micrograms/L; P < 0.001). In the second group of 12 hypothyroid patients, arginine infusion (30 g, iv, from 0-30 min) markedly increased the GH responses induced by GHRH administration (1 microgram/kg, iv, at 0 min; peak GH levels for arginine plus GHRH vs. placebo plus GHRH, 30.6 +/- 4.7 vs. 5.3 +/- 1.0 micrograms/L; P < 0.001). However, GH release after GHRH plus arginine was greater in 10 normal subjects than in the hypothyroid patients (peak GH levels, 50.9 +/- 5.3 micrograms/L; P < 0.001). Pyridostigmine and arginine inhibit hypothalamic somatostatin tone. The stimulatory effect of both agents on GHRH-induced GH release indicates that reduced GH secretion in hypothyroidism can be reversed to a considerable extent by inhibiting hypothalamic somatostatinergic tone. The relatively greater potency of arginine compared to pyridostigmine suggests that hypothyroid patients may have an impairment of the cholinergic pathways. Furthermore, these data show that hypothyroid patients have a somatotrope secretory capacity much greater than previously thought.

Adult↗
PubMed1992

Long-term therapy with high-dose simvastatin does not affect adrenocortical and gonadal hormones in hypercholesterolemic patients.

Simvastatin is an effective hypocholesterolemic drug that inhibits cholesterol synthesis selectively in the liver, but could have potential side effects on the adrenal gland, ovary, and testis, as these three glands use cholesterol for their hormonal biosynthesis. In this report, we examined adrenal and sex steroids in 10 type IIA hypercholesterolemic patients (three with familial [FH] and seven with polygenic hypercholesterolemia) over a period of 1 year on simvastatin therapy in order to confirm in vivo its selective action. Furthermore, we evaluated the adrenal reserve by a corticotropin rapid test, before starting treatment and again at the end of the third month on 20 mg of simvastatin per day, then at the sixth and 12th month on 40 mg/d. There was a significant lowering of total cholesterol (TC) (-31%), low-density lipoprotein cholesterol (LDL-C) (-39%), and apolipoprotein (apo) B (-39%); no statistically significant differences were seen in cortisol response to the corticotropin test between baseline and simvastatin-treated patients. No variation of any sex steroid was observed in patients of either gender. We conclude that long-term therapy with high-dose simvastatin does not interfere with either adrenocortical function or sex hormone production.

Adrenal Cortex Hormones↗
PubMed1992

The late growth hormone rise induced by oral glucose is enhanced by cholinergic stimulation with pyridostigmine in normal subjects.

OBJECTIVE: We have investigated the late GH rise occurring 3-5 hours after oral glucose administration. We have assessed the effect of endogenous cholinergic enhancement with pyridostigmine on the delayed GH rise following oral glucose loading in normal subjects. DESIGN: Placebo or 75 g oral glucose was given to the normal subjects 3 hours before 120 mg oral pyridostigmine or placebo. Four tests were carried out at random. (0 min) + placebo (180 min); test 2: glucose (0 min) + placebo (180 min); test 3: placebo (0 min) + pyridostigmine (180 min); test 4: glucose (0 min) + pyridostigmine (180 min). SUBJECTS: We studied eight normal subjects (four male and four female), ages 19-29 years, body mass indices 18-22 kg/m2. MEASUREMENTS: Plasma glucose and serum GH concentrations were measured for 6 hours after oral glucose or placebo administration. RESULTS: Pyridostigmine treatment significantly enhanced the GH releasing effect of prior (3 h) oral glucose. Late GH peak obtained by oral glucose loading rose from (mean +/- SEM) 17.4 +/- 4.6 to 37.2 +/- 9.0 mU/l (P < 0.05) after pyridostigmine, while GH peak following placebo plus pyridostigmine was 12.4 +/- 2.0 mU/l (P < 0.05 vs glucose plus pyridostigmine). The analysis of GH area under curves (AUCs) in the second phase of the tests (180-360 min) confirmed that glucose plus pyridostigmine released a greater amount of GH (4128 +/- 764 mU/l/3h) than glucose (1694 +/- 494 mU/l/3h, P < 0.001) or pyridostigmine alone (1292 +/- 150 mU/I/3h, P < 0.001). CONCLUSIONS: Pyridostigmine, an indirect cholinergic drug likely to inhibit somatostatin secretion from the hypothalamus, enhanced the late GH releasing activity of oral glucose. There is evidence that glucose suppresses plasma GH initially by increasing hypothalamic somatostatin release. This would result in an increase in the pituitary stores of GH. We propose that the delayed GH rise after oral glucose occurs when there is a fall in hypothalamic somatostatinergic tone; this is further reduced by the administration of pyridostigmine. At this time the pituitary stores of GH are released as a consequence of resumption of hypothalamic GHRH activity. This leads to the late GH rise.

Administration, Oral↗
PubMed1992

The cervical spine in patients with psoriatic arthritis: a clinical, radiological and immunogenetic study.

The radiological changes of the cervical spine were evaluated in 57 patients with psoriatic arthritis and were correlated with clinical, radiological, and immunogenetic features of the disease. Forty patients (70%) showed radiological evidence of the cervical spine being affected by the disease. Two patterns of cervical spine abnormalities were noted. Fifteen patients (26%) had erosive and/or subluxing cervical rheumatoid like lesions; 25 patients (44%) had a more frequently reported pattern similar to ankylosing spondylitis. Although subaxial subluxations were the most frequently observed cervical abnormalities (53%) in the inflammatory subgroup, none of the patients studied had cord compression. Ankylosing cervical spine disease was the only form of axial involvement in nine (36%) of 25 patients with the ankylosing form of psoriatic arthritis. All of these patients had peripheral disease and were B27 negative. Predictors of cervical spine disease patterns were considered using clinical, demographic, and radiological features and HLA antigens. The results of a multivariate analysis showed that the best predictors of inflammatory cervical spine disease are the presence of HLA-B39 and HLA-DR4 antigens, radiocarpal erosions, and the absence of the HLA-DR5 antigen.

Arthritis, Psoriatic↗
PubMed1992

Sinus node function in hyperthyroid patients.

We have studied the electrophysiology of the sinus node and the role of the autonomic nervous system on sinus node function in 8 thyrotoxic patients of both sexes, 37.5 +/- 4.3 (mean +/- SE) yr old. The resting heart rate (RHR), the sino-atrial conduction time (SACT), and the sinus node recovery time (SNRT) were measured in the untreated condition (basal), after sympathetic blockade with propranolol 0.2 mg/kg body weight (BW) i.v. infusion, and after complete autonomic blockade with the additional administration of atropine 0.04 mg/kg BW i.v. bolus. 1) In the thyrotoxic patients the RHR was higher [117 +/- 6 beats per min (bpm)] than in 20 normal subjects (73 +/- 1 bpm, P less than 0.001), whereas the SACT and SNRT values were not different. 2) After sympathetic blockade with propranolol, the RHR decrement and SACT increase were greater in the hyperthyroid patients than in normal subjects, whereas there was no difference in SNRT values between the two groups. 3) In the thyrotoxic patients the complete autonomic blockade reestablished the electrophysiological parameters to values similar to those observed in basal condition. In conclusion, in thyrotoxic patients the intrinsic activity of the sinus node is increased. It appears that this is a direct consequence of thyroid hormone excess, rather than an effect of extrinsic influences exerted by the autonomic nervous system on sinus node activity.

Adolescent↗
PubMed1992

Immunologic effects in patients with psoriatic arthritis treated with cyclosporine A.

Twelve patients with psoriatic arthritis (PsA) and very active articular disease resistant to conventional second line therapy entered into a 6-month open study of cyclosporine A (CsA) at a starting dosage of 3 mg/kg/day. Comparisons of phenotypic characteristics of lymphocytes and response to mitogens of peripheral blood mononuclear cells (PBMC) were made between these patients with PsA before CsA therapy, 7 patients without prior 2nd line therapy, 14 untreated patients with psoriasis alone, and 61 healthy controls. We confirmed a significant reduction of the basal percentage of CD8+ cells and an increase in the CD4/CD8 ratio in patients with PsA before CsA therapy compared to controls. These abnormalities were not present in patients with PsA without prior 2nd line therapy and in patients with psoriasis alone. Peripheral blood activated T cells (CD3+, HLA-DR+), natural killer (NK) (CD3-, CD16+ and/or CD56+), total B and CD5+ B cells were decreased only in patients with PsA before CsA therapy. The reduction of non-MHC restricted cytotoxicity T (CD3+, CD16+ and/or CD56+) was observed in all the 3 groups of patients compared to controls. After the 6 months of CsA therapy we observed a significant increase of CD3+, HLA-DR+, CD3+, CD16+ and/or CD56+, total B, and CD20+, CD5+ cells in the 11 patients with PsA compared to pretreatment values. Contrary to azathioprine, CsA does not impair the NK cell population which has a protective role against cancer and viral infections.

Antigens, CD↗
PubMed1992

Soluble interleukin 2 receptors in polymyalgia rheumatica/giant cell arteritis. Clinical and laboratory correlations.

Serum levels of soluble interleukin 2 receptors (sIL-2R) were measured in 21 patients with polymyalgia rheumatica (PMR)/giant cell arteritis (GCA) prior to steroid treatment. These levels were significantly elevated in patients with PMR/GCA compared with healthy controls (p = 0.002). A significantly longer duration of morning stiffness (p = 0.005) was observed in patients with a high concentration of sIL-2R. A significant correlation was observed at diagnosis between sIL-2R and erythrocyte sedimentation rate (ESR) (p = 0.01) and between ESR and C-reactive protein (CRP) (p = 0.005). We investigated prospectively a group of 10 patients over a period of 6 months of prednisone therapy. At the end of the study sIL-2R levels fell significantly compared to pretreatment values (p = 0.02), but remained significantly higher compared to controls (p = 0.02). ESR and CRP values also fell significantly compared to pretreatment levels (p = 0.0001 in both cases). We observed a significant correlation between the decrease in ESR values and the decrease in sIL-2R and CRP levels after 6 weeks (p = 0.01 in both cases) and after 6 months of therapy (p = 0.002 and p = 0.05). sIL-2R may be considered a useful serologic marker for monitoring response to steroid therapy in patients with PMR/GCA. This laboratory variable correlated more closely with ESR than with CRP. The presence of elevated levels of sIL-2R is likely to reflect T cell activation occurring in PMR/GCA. T lymphocyte activation persisted after 6 months of steroid therapy, despite rapid and continuous control of disease manifestations.

Aged↗
PubMed1992

Low dose cyclosporine A in psoriatic arthritis: relation between soluble interleukin 2 receptors and response to therapy.

Twelve patients with psoriatic arthritis (PsA) were treated with low doses of cyclosporine A (CsA) (the initial dose was 3 mg/kg daily) and were entered into an open 6-month study. At the end of the study arthritis was improved in 7 patients (number of patients achieving a 50% or more reduction in the number of swollen or tender joints) and unchanged in 4 patients. Cutaneous psoriasis also improved significantly as shown by psoriasis area and severity index score. Only one patient withdrew from the study after one month because of severe nephrotoxicity. Serum creatinine fell to baseline value 6 weeks after the discontinuation of CsA. Three patients had minor side effects. CsA maintained articular improvement also in the 9 patients who are still taking this drug (mean duration of therapy of 12 +/- 0.8 months). There was no significant reduction of erythrocyte sedimentation rate during the study period. We assayed levels of soluble interleukin 2 receptors (sIL-2R) in serial serum samples obtained from 10 patients during the study period. Concentrations of sIL-2R were significantly increased in patients with PsA compared to controls. In 6 responder patients we observed a parallel decrease in joint pain/tenderness score and serum sIL-2R values. This finding was not observed in 4 nonresponders. Our results suggest that low dose CsA is a short term effective and safe therapy in patients with PsA and that serial sIL-2R levels are a useful means of measuring changes in disease activity.

Arthritis, Psoriatic↗
PubMed1992

Extraarticular manifestations of rheumatoid arthritis and HLA antigens in northern Italy.

We performed retrospective analysis of 141 Northern Italian patients with rheumatoid arthritis (RA). This series represents all the patients seen as in and/or outpatients at the rheumatologic unit of Reggio Emilia Hospital during a 2 year period (1987-88). We observed a low frequency of nodules (16%) and vasculitis (2.1%). Thus, RA seems to be milder in our population compared to Caucasian patients with RA originating from North America or England. We observed a weak association with DR4 (RR = 2.4) in the total group of patients with RA. A low frequency of DR4 was observed in patients and controls (29 vs 14.5%, p = 0.001). When compared with controls the frequency of DR4 was significantly higher in seropositive (p = 0.001), but not in seronegative patients. We found that DR4 was significantly associated with nodules (RR = 6.4), with extraarticular features (EAF) (RR = 4) and with erosions (RR = 3) compared with controls. The subgroups with nodules and EAF had a DR4 frequency (respectively, of 52 and 40%) which was significantly higher than that observed in remaining patients (respectively, 25 and 24%). No significant difference was observed in the DR4 frequency between the patients with erosions and those without (34 vs 18%). Thus, DR4 in our population seems to be predominantly associated with a subgroup of patients characterized by seropositivity and EAF.

Aged↗