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Biomedical subjects

M Maccario

Publications and source records attributed to M Maccario.

136 records · Page 8Linked to original sources
PubMedDate not supplied

Low dose orally administered arginine is able to enhance both basal and growth hormone-releasing hormone-induced growth hormone secretion in normal short children.

Aim of this study was to verify whether arginine (ARG), which likely inhibits hypothalamic somatostatin release, has an enhancing effect on the GHRH-induced GH rise, even when administered orally at low dose. To this goal we studied the effects of 4 g orally administered ARG, either hydrochloride (ARG-H) or aspartate (ARG-A), on both basal and GHRH (1 microgram/Kg i.v.)-stimulated GH secretion in 31 children with familial short stature (11 males and 20 females, aged 5.5-13.8 yr, pubertal stage I-III, and compared the results with those of i.v. infusion of 0.5 g/kg ARG-H. Oral ARG-H (Group A, n = 11) induced a significant increase of basal GH levels (4.2 +/- 1.3 vs 1.0 +/- 0.4 micrograms/L, p < 0.02) and enhanced the GH response to GHRH (41.1 +/- 8.6 vs 25.3 +/- 6.7 micrograms/L, p < 0.02). Oral ARG-A (Group B, n = 10) induced a slight, but not statistically significant increase in serum GH levels (3.4 +/- 1.5 vs 1.0 +/- 0.3 micrograms/L) and enhanced the GHRH-induced GH rise (49.7 +/- 9.8 vs 26.1 +/- 8.4 micrograms/L, p < 0.05). Intravenous ARG-H (Group C, n = 10) stimulated basal GH levels (6.2 +/- 1.2 vs 1.2 +/- 0.3 micrograms/L, p < 0.005) and increased the GHRH-induced GH rise (46.7 +/- 5.0 vs 17.1 +/- 2.3 micrograms/L, p < 0.005). This response was similar to those after oral ARG-H or ARG-A plus GHRH. No variation was observed in PRL levels after oral ARG (either ARG-H or ARG-A) and/or GHRH.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMedDate not supplied

GH response to GHRH combined with pyridostigmine or arginine in different conditions of low somatotrope secretion in adulthood: obesity and Cushing's syndrome in comparison with hypopituitarism.

BACKGROUND: Diagnosing GH deficiency in adults is difficult due to the age-related variations of GH/IGF-I axis and the influence of nutrition. Nowadays, GH replacement is allowed for patients with GH peak to provocative stimuli < 3 micrograms/L. Somatotrope insufficiency is present in hypopituitarism but also in obesity and hypercortisolism. However, to evaluate GH insufficiency in adults is difficult due to variations of GH and IGF-I levels as function of age and nutrition status. METHODS: We aimed to verify the GH response to GHRH (1 mg/kg i.v.) combined with pyridostigmine (PD, 120 mg p.o.) or arginine (ARG, 0.5 g/kg i.v.), in 26 hypopituitaric patients (GHD), in 11 obese women (OB), in 8 women with Cushing's syndrome (CS), and in 72 control subjects (NS). RESULTS: IGF-I levels in GHD were lower than those in OB (p < 0.01) and in CS (p < 0.01) which, in turn, were lower to those in NS (p < 0.02). In NS, the GH peak responses to GHRH + PD and GHRH + ARG were similar and the minimum normal GH peak was 16.5 mg/L. GHD had GH responses similar, lower than those in NS (p < 0.01) and always below the normal limit. However, only 12/20 and 8/14 had peaks < 3 micrograms/L; conventionally, below this limit severe GH deficiency is shown and rhGH replacement is allowed. In OB, the GH responses to GHRH + PD and GHRH + ARG were similar, lower (p < 0.01) and higher (p < 0.01) than those in NS and GHD, respectively. Six out of 11 OB had GH peaks below the normal limits but nobody < 3 micrograms/L. In CS, the GH response to GHRH + PD was lower than that to GHRH + ARG (p < 0.01); both these responses were lower than those in NS (p < 0.01) and even in OB (p < 0.01) but higher than those in GHD (p < 0.01). All and 7/8 CS had GH peaks lower than normal limits after PD + GHRH and ARG + GHRH, respectively while 6/8 showed GH peak < 3 micrograms/L after PD + GHRH but only 1 after ARG + GHRH. CONCLUSIONS: Present data demonstrate that the maximal somatotrope secretory capacity is reduced in OB and even more in CS. From a diagnostic point of view, PD + GHRH and ARG + GHRH tests distinguish OB from severe GHD. As hypercortisolism impairs the activity of cholinesterase inhibitors, only ARG + GHRH, but not PD + GHRH is a reliable test to explore the maximal somatotrope secretory capacity in CS. Notably, even with the ARG + GHRH test, in CS the maximal somatotrope secretory capacity is sometimes so reduced as to overlap with that of severe GHD.

Adult↗
PubMedDate not supplied

[Morpho-functional study of peritoneum in peritoneal dialysis].

BACKGROUND: Peritoneal dialysis (PD) impairs both structure and function of the peritoneal membrane (PM). Aim of the study is to examine the relationship among dialytic, histological and functional parameters in PD patients. METHODS: Thirty-one PD patients were submitted to peritoneal biopsy (PB) during catheter removal for malfunction or after dropping out of the treatment. For each patient PM transport was evaluated by the last peritoneal equilibration test (PET) prior to PB. Each daily glucose load was calculated. PB was performed at a distance of at least 5 cm from the catheter insertion point. The tissues were promptly embedded in formalin and stained for histological and immunohistochemical studies. RESULTS: 1) Patients with mesothelial impairment had longer treatment time. 2) Patients presenting submesothelial sclerosis (SS) and those with impairment of submesothelial basement membrane and subendothelial vascular membrane (SVM) were submitted to larger daily glucose loads. 3) High transporters were exposed to larger daily glucose loads and presented an SS thickness greater than 50 micron more frequently than medium-high transporters. 4) Mesothelial loss was correlated with SS and vascular alterations. 5) SS and vascular injuries were related to each other and not to inflammatory infiltrate. CONCLUSION: Our study suggests that PD length seems to be mainly involved in mesothelial impairment; glucose load appears to damage mainly the submesothelial layer; SS is not a constant event in PD patients and in itself does not seem to be a decisive factor in PD drop out.

Adult↗
PubMedDate not supplied

[On-line hemodiafiltration with endogenous reinfusion (HFR). Experience of a Centre].

PURPOSE: Hemodiafiltration reinfusion (HFR) treatment is a dialysis technique that uses the endogenous reinfusion fluid and performs, simultaneously and separately, the three mechanisms of extracorporal depuration: diffusion, convection and adsorption. This study aimed to evaluate clinical and biochemical data of a group of six patients submitted to a dialytic HFR method for >6 months. METHODS: Six patients with a mean age of 53.8 +/- 11 yrs (five males, one female), treated with standard bicarbonate dialysis for a mean of 79.2 months, underwent HFR for a mean period of 14.9 +/- 6 months. Filters used were: a) in all patients polysulfone with 0.7 m2 of surface for the convection; b) polysulfone with 1.7 m2 in one patient, and modified cellulose with 2.0 m2 in five patients for diffusion; c) hydrophobic interaction resin and uncovered mineral carbon 240 mL for the adsorption. For all patients dialysis duration was 240 min and the amount of reinfusion fluid was 2.5 L/h as a mean, calculated according to blood flow and hematocrit (Hct), keeping a filtration fraction <22%. We evaluated, at different times, the following parameters: a) patient weight; b) Hct and erythropoietin (EPO) doses; c) parathyroid hormone (PTH); d) phosphatemia and doses of administered vitamin D; e) homocysteine (Hcy) and Beta2-microglobulin (Beta2-m); f) and albuminemia and transferrinemia as nutritional parameters. RESULTS: We observed an increase in Hct, with a reduction in EPO dosage, and an increase in albumin and transferrin levels, an improvement in nutritional indexes and in patient well-being. The mild increase in Hct with the same EPO dose was present in spite of a switch to intravenous (i.v.) administration from subcutaneous administration. There was low morbidity and only one hospitalization due to an infectious episode. CONCLUSIONS: HFR allows an amino acid saving and pro-inflammatory middle molecule removal, resulting in a better clinical situation for progressively critical uremic patients.

Female↗
PubMedDate not supplied

Comparison of Monotard and Ultratard insulin at bedtime in a model of optimized insulin therapy in Italy.

The italian habit of having a low calorie breakfast suggests an insulin treatment made up of two daily injections of soluble insulin before lunch and dinner, adding at bed time an injection of retard insulin. Aim of this study was to verify whether Monotard or Ultratard proved more effective as retard insulin in this regimen. Sixteen insulin-dependent diabetics treated with the above-mentioned insulin regimen were studied for 16 weeks. They were divided in two groups: group 1 was treated initially with Ultratard and group 2 with Monotard, with a cross-over after 8 weeks. The metabolic control achieved with the treatment was considered good with either retard insulin used. HbA1c, fructosamine, body weight and glycemic values measured after 8 and 16 weeds failed to reveal any differences between the treatment with Monotard on Ultratard. Either Monotard or Ultratard can be successfully used as bedtime retard insulin in this multiple injection insulin treatment.

Adult↗