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Biomedical subjects

G Conte

Publications and source records attributed to G Conte.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Acute poisoning with methotrexate used as an abortifacient: description of 2 cases].

Acute intoxication with methotrexate, used as an abortive, has not been described in Chile. We report two female patients, aged 15 and 24 years old, who presented with mucositis, erythrodermia, pancytopenia, and elevation of hepatic enzymes. Plasma methotrexate levels confirmed the clinical diagnosis and both patients were treated with high leucovorin doses and management of associated complications. In one patient, pregnancy continued, giving birth to a newborn with cranial, face and limb malformations. The second patient had a late rescue with leucovorin and was discharged with a persistent sensory motor neuropathy. Considering the severity of complications and that patients may deny its use, when there is reasonable clinical suspicion of methotrexate intoxication, leucovorin treatment should be started.

Abortifacient Agents, Nonsteroidal↗
PubMed2000

[Severe Henoch-Schonlein purpura in a patient with multiple myeloma].

A Multiple Myeloma (MM), IgG-lambda stage III-A was diagnosed in a 41-year-old-man. After VAD cycles IgG decreased from 7.5 to 2.4 g/dL. were mobilized with cyclophosphamide and 10 micrograms/Kg G-CSF. Three days after the collection of peripheral stem cell, the patient had fever, nausea, vomiting, liquid stools, shoulder and knee arthralgia and dehydration. Upper GI endoscopy showed esophageal candidiasis and ulcerative necrotic lesions both in stomach and duodenum; the biopsy confirmed necrosis. Simultaneously, the appearance of purpura with maculopapular lesions of diverse sizes appeared in the feet progressing to the limbs and trunk. Hematuria and proteinuria were also observed. Skin biopsy showed leukocytoclastic vasculitis. Renal biopsy showed focal and segmental glomerulonephritis. Serum ANCA, cryoglobulins, anti-HCV and RF were negative, and serum monoclonal IgG was 1290 mg/dL. Daily treatment with i.v. methylprednisolone pulses for 3 days improved skin lesions and digestive involvement. Macroscopic hematuria and proteinuria improved after two months of steroid treatment.

Adult↗
PubMed1999

Diagnosis of renal disease at the beginning of the 20th century.

At the beginning of this century, the diagnosis of various renal diseases was made with relative accuracy although neither plasma markers of glomerular filtration nor renal biopsy nor imaging were available. Renal edema was identified by high albuminuria, hyalin cylinders, high urine density and oliguria. Renal hematuria was detected by cylinders of erythrocytes. Hallmarks of chronic renal insufficiency, recognized at autopsy by atrophic kidneys, were hyposthenuria, polyuria and slight albuminuria without edema associated with arterial hypertension, anemia, retinopathy and left ventricular hypertrophy. The detection of increased plasma volume in experimental toxic nephritis by St. Moscati proposed the underlying mechanism of arterial hypertension. Experimental and clinical research in the preinsulin era indicated the central role of the kidney in the functional alterations induced by diabetes. Indeed, glucosuria was known to appear only when glycemia was relatively high. The kidney appeared enlarged and hyperemic, i.e. the so-called glomerular hyperfiltration. Glucosuria was directly correlated with diuresis but it markedly decreased in renal insufficiency. In diabetes complicated by nephropathy, tolerance to carbohydrates improved. Correction of glucosuria by dietary treatment was followed by a prompt rise in body weight, due to retention that counterbalanced the previous losses. Diabetic ketoacidosis, determined by the measurement of urinary ketonic body excretion, was treated with sodium bicarbonate (30-50 g/day in severe acidosis) up to achieving an alkaline urine pH. It was known that high doses of sodium bicarbonate might induce edema which gradually disappeared with a reduction in the alkaline administration. Clinical significance of sodium balance was, in fact, recognized: the external NaCl balance between alimentary ingestion and urinary excretion was neutral in normal conditions and became positive at high body temperature or negative during reabsorption of exudates.

Animals↗
PubMed1999

Effects of water hardness on urinary risk factors for kidney stones in patients with idiopathic nephrolithiasis.

Both amount and timing of dietary calcium intake influence the recurrence of renal calcium stones. We have evaluated whether the hardness of extra meal drinking water modifies the risk for calcium stones. The urinary levels of calcium, oxalate and citrate, i.e., the main urinary risk factors for calcium stones, were measured in 18 patients with idiopathic nephrolithiasis, maintained at fixed dietary intake of calcium (800 mg/day), after drinking for 1 week 2 liters per day, between meals, of tap water and at the end of 1 week of the same amount of bottled hard (Ca2+ 255 mg/l) or soft (Ca2+ 22 mg/l, Fiuggi water) water, in a double-blind randomized, crossover fashion. As compared with both tap and soft water, hard water was associated with a significant 50% increase of the urinary calcium concentration in the absence of changes of oxalate excretion; the calcium-citrate index revealed a significant threefold increase during ingestion of hard water as compared with respect to soft water (Fiuggi water), making the latter preferable even when compared with tap water. This study suggests that, in the preventive approach to calcium nephrolithiasis, the extra meal intake of soft water is preferable to hard water, since it is associated with a lower risk for recurrence of calcium stones.

Biomarkers↗
PubMed1999

Reactive oxygen species in male infertility. Review of literature and personal observations.

Reactive oxygen species, highly reactive molecules derived from the metabolism of oxygen, play an important role in the metabolism of spermatozoa, related to the hyperactivated motility and acrosome reaction. Various studies have demonstrated that these molecules, because of their reactivity, can induce peroxidative damage on the cell, especially on the lipid membranes. The spermatozoa, owing to their structure, appear to be very sensitive to the oxidative insult. Various experimental data sustain the hypothesis that, when produced in high amounts, reactive oxygen species can induce sperm damage and become potentially responsible for some forms of unexplained infertility. The cells possess various mechanisms of defense against the oxidative insult, mainly due to antioxidant molecules. An antioxidant treatment can produce an improvement in seminal parameters and sperm function in vitro, and represents a possible form of care for selected forms of infertility.

Fertilization↗
PubMed1999

Acute cardiovascular diseases and respiratory sleep disorders.

Respiratory sleep disorders are a risk factor, sometimes independent, for acute cardiovascular diseases which are the most frequent cause of death among populations of industrialized countries. Snoring and obstructive sleep apnea (OSA) are generally involved, while the pathogenetic role of acute exacerbation of COPD seems less evident. The most important acute cardiovascular events related to sleep respiratory disorders are angina pectoris, acute myocardial infarction, cardiac arrhythmias (in some instances as paroxysmal attacks), systemic hypertension with hypertensive crisis, ischemic stroke. A respiratory sleep disorder should be suspected in all obese, cigarette smokers, alcoholics, hypertensives, who present symptoms of obstructive sleep apnea, where snoring may be a marker, and in patients with COPD. The diagnosis is readily established by performing polysomnography and, when needed, by 24-hour Holter monitoring and blood pressure ambulatory recording. Therapy aims at correcting risk factors with particular attention to weight reduction in obese patients. Furthermore, upper airway anatomic abnormalities should be eliminated. In obstructive sleep apnea, nasal continuous positive airway pressure during sleep is to be used, when necessary, while tracheostomy must be performed only in more severe cases.

Acute Disease↗
PubMed1998

Salt intake and renal outcome in patients with progressive renal disease.

Experimental studies suggest that salt intake plays a critical role in the progressive glomerular filtration rate (GFR) loss of established renal disease; however, this issue has never been addressed in humans. To this aim, we have retrospectively analyzed the clinical data of patients with chronic renal failure (CRF), in whom a low-protein diet was prescribed, over a period of about 3 years. On the basis of the daily urinary sodium output, the patients were divided into two groups: a group of patients constantly ingesting > 200 mEq NaCl/day (high sodium intake, HSD, n = 30) and a group in which salt intake was < 100 mEq/day (low sodium intake, LSD, n = 27). Patients taking diuretics or ACE inhibitors were excluded. At baseline, the LSD group, as compared to the HSD group, was characterized by significantly lower creatinine clearance (24 +/- 2 vs. 28 +/- 2 ml/min) and higher proteinuria (2.9 +/- 0.3 vs. 1.5 +/- 0.2 g/day). Despite the presence of these risk factors for progression, and a similar control of blood pressure (the average of the mean arterial pressure during follow-up was 111 +/- 2 mm Hg in LSD and 107 +/- 2 mm Hg in HSD), the LSD patients showed a better renal outcome: in this group, as compared to HSD, the GFR decline was lower (0.25 +/- 0.07 vs. 0.51 +/- 0.09 ml/min/month, p < 0.05), and proteinuria did not change while it markedly increased in HSD. During follow-up, LSD patients also ingested a significantly lower amount of protein. This study therefore suggests that efficacious salt restriction in CRF patients improves the outcome of renal disease independent from its antihypertensive effects.

Blood Pressure↗
PubMed1998

[Application of chronotherapy to cardiovascular diseases].

Among cardiovascular diseases, hypertension, angina pectoris, acute myocardial infarction and ischemic stroke present a circadian pattern with a greater incidence of unfavourable events between awakening and noon. Chronotherapy aims to use drugs that release their active principles at different times during the day, according to biological needs. In chronotherapy of cardiovascular diseases, a particular attention has been paid to slow-release drugs that assure a 24 hours therapeutic effect with once a day administration. In primary hypertension well controlled by monotherapy (dipper hypertensives), the morning administration of long-acting beta-blockers and calcium antagonists has shown to control blood pressure over 24 hours, whereas ACE-inhibitors have proved more effective when administered at evening. In secondary hypertension (non dipper hypertensives) the administration of calcium antagonists is more effective at evening. Patients with severe hypertension need polytherapy. In that case, at least one of the antihypertensive drugs should be given at evening to lower night blood pressure values, which are particularly elevated also during sleep, and so to prevent an excessive blood pressure rise on awakening. In chronic monotherapy of ischemic heart disease, long-acting beta-blockers and calcium antagonists have shown to be equally effective when they are administered at morning, whereas slow-release nitrates, which need a nitrate-free interval, are to be administered either at morning or at evening, according to the expected time of onset of anginal pain. ASA seems to reduce the morning incidence of acute myocardial infarction, while tissue-type plasminogen activator presents a circadian variation of its thrombolytic activity with a higher efficacy between noon and midnight.

Cardiovascular Agents↗
PubMed1997

Physiological role of the opioid-cholinergic interaction in growth hormone neuroregulation: effect of sex and food intake.

Studies performed in animals and humans have suggested a functional interaction between opioid and cholinergic systems in the control of growth hormone (GH) secretion. Moreover, the sex-dependent modulation of GH secretion in humans is well established. To investigate the role of sex and food intake in the regulation of the reciprocal influences of opioids and acetylcholine in the modulation of GH secretion, we studied the GH response to pyridostigmine (PYR) alone and during a naloxone (NAL) infusion in a group of normal men and women before a meal (at 1:00 PM) and postprandially. In women, the response of GH to PYR alone before the meal was significantly lower than in the men (area under the curve [AUC], mean +/- SEM, 320.18 +/- 87.16 v 1,031.06 +/- 333.21 micrograms/L/90 min, P < .01). Before the meal, NAL completely abolished the response of GH to PYR in men (AUC, 1,031.06 +/- 333.21 v 16.50 +/- 7.50 micrograms/L/90 min, P < .01), whereas infusion of NAL did not significantly modify the GH response to PYR in women. Consumption of the meal significantly decreased PYR-induced GH release in both women (AUC, 21.75 +/- 12.75 v 320.18 +/- 87.16 micrograms/L/90 min, P < .05) and men (AUC, 45.75 +/- 18.75 v 1,031.06 +/- 333.21 micrograms/L/90 min, P < .01). Conversely, food intake did not change the effects of NAL infusion on the GH response to PYR either in women or in men. We conclude that the sex-dependent opioid modulation of PYR-induced GH secretion is observed before a meal but not in the postprandial state. Food intake may be hypothesized to influence the cholinergic regulation of GH secretion and the sex-dependent opioid modulation of central cholinergic tone.

Adult↗
PubMed1997

Pathophysiological role and diuretic efficacy of atrial natriuretic peptide in renal patients.

It has been suggested that renal disease is characterized by the presence of resistance to the natriuretic effects of atrial peptide (ANP). In this study, plasma ANP (pANP) and renal function were evaluated during stepwise infusion of low ANP doses (2, 4, 8, and 16 ng/kg per min) in glomerulonephritic patients with (CRF) or without (GN) moderate renal failure, and in normal subjects (NOR), kept at low-sodium diet (LSD; 35 mEq NaCl/day). To assess the physiological ANP levels, pANP was also measured in the three groups after normal-sodium diet (NSD; 235 mEq NaCl/day). ANP did not affect systemic and renal perfusion at any of the doses tested; a significant increment of GFR was observed only in NOR and GN. The 2-, 4-, and 8-ng/kg doses increased pANP to values overlapping the physiological concentrations measured at NSD; this was associated with a dose-dependent increment of urinary excretion of sodium (UNaV) that reached analogous levels in the three groups. ANP accounted for approximately 40% of the UNaV increment evoked by NSD in patients and in normal subjects. The 16-ng/kg dose led to supraphysiological levels that induced a similar marked enhancement of UNaV (from the basal value of 0.12 +/- 0.02 to 0.42 +/- 0.08 mEq/min in CRF, from 0.13 +/- 0.02 to 0.73 +/- 0.08 in GN, and from 0.09 +/- 0.02 to 0.49 +/- 0.11 in NOR). In CRF, the normal natriuretic response to the highest dose was caused by a larger increase of fractional UNaV that was strictly dependent on the greater pANP increment, as demonstrated by similar changes in the fractional excretion of cGMP, and, in part, on the greater aldosterone decrease. In all groups, ANP also induced a dose-dependent urinary loss of phosphate, potassium, and urea, resulting in a significant 15 to 25% decrease in the plasma levels. Thus, in GN and CRF patients, ANP plays a significant role in the renal handling of sodium; moreover, the achievement of low supraphysiological pANP levels leads to a conspicuous natriuresis associated with unique extranatriuretic effects.

Adult↗
PubMed1997

Physiologic role and diuretic efficacy of atrial natriuretic peptide in health and chronic renal disease.

In recent years, different clinical studies have provided new information on the pathophysiological role and diuretic effectiveness of atrial natriuretic peptide (ANP) in subjects with normal renal function and patients with chronic renal disease. Plasma ANP (pANP) was increased by infusion at the lowest doses ever tested in humans who were on low salt diet to the levels that the same subjects gained when on a normal salt diet; ANP accounted for at least 40% of the increase of natriuresis. Similarly, ANP appeared to be mainly involved in the physiological down-regulation of salt excretion (that is, during the shift from a normal to low-sodium diet). Interestingly, data have been also attained on the efficacy of ANP as diuretic agent when administered at a low nonhypotensive dosage in normals as well as CRF patients. Indeed, low-dose ANP promoted a marked increase of sodium excretion in CRF patients to the same levels observed in normals, likely because the renal patients exhibited a more marked pANP increment secondary to the lower renal catabolism of the infused hormone. Moreover, aldosterone suppression was greater in CRF patients with respect to normals. Furthermore, the fractional urinary excretion of cGMP increased more in CRF patients than in normals. Finally, ANP infusion augmented the urinary losses of the main solutes retained in CRF (urea, potassium, phosphorous) with a significant decrease in the plasma levels. Hence, ANP per se not only plays a significant role in the up- and down-regulation of sodium excretion in healthy state and chronic renal disease, but it may also be considered to be a powerful and unique diuretic agent in CRF at nonhypotensive dosages.

Animals↗
PubMed1997

[Evaluation of hyperkinetic cardiac arrhythmia in chronic obstructive bronchopneumopathy].

Patients with chronic obstructive pulmonary disease (COPD), especially during acute exacerbations of their disease, show a greater incidence of cardiac arrhythmias than healthy subjects of the same age. The type of arrhythmias found may be supraventricular (premature atrial beats, paroxysmal supraventricular tachycardia, multifocal atrial tachycardia, atrial flutter, atrial fibrillation) or ventricular (premature ventricular beats, sustained ventricular tachycardia, torsades de pointes, ventricular fibrillation) that may lead to sudden cardiac death. The pathogenesis of arrhythmias is complex and many factors may be involved such as hypoxemia, hypercapnia, respiratory acidosis, metabolic and respiratory alchalosis, hypokalemia, concomitant ischemic heart disease, chronic cor pulmonale, left ventricular diastolic dysfunction. Remarkable attention has been drawn to the possible arrhythmogenic effect of drugs such as theophylline, beta-adrenergic stimulants and digitalis which are commonly used in the therapy of COPD. Both of the main classes of bronchodilators (methylxanthynes and beta-adrenergic agonists), even when used together, apparently do not increase the incidence of dangerous cardiac arrhythmias. However, these drugs should be used with caution in the elderly, in patients with preexisting cardiac arrhythmias, with heart disease or with reduced hepatic function. In these cases Holter monitoring, repeated measurements of plasma drugs concentration and prompt hospitalization of high risk patients in Intensive Care Unit may be needed.

Adrenergic beta-Agonists↗
PubMed1996

Pre- and postprandial pyridostigmine and oxiracetam effects on growth hormone secretion in anorexia nervosa.

Previous studies have shown that food ingestion is not capable of inhibiting the GHRH-induced GH release in anorexia nervosa, at variance with what is observed in normal subjects. Moreover, a cholinergic alteration has been hypothesized in this disorder. In a group of 24 anorectic patients in a stabilized phase of the illness, we tested, before and after a standard meal, the GH response to GHRH alone and after pre-treatment with pyridostigmine, an inhibitor of acetylcholinesterase, and, on a different day, with oxiracetam, which stimulates the central cholinergic neurones. The GH response to GHRH was significantly increased by both drugs in a fasting state. The postprandial response was not significantly modified by pyridostigmine nor by oxiracetam. Neither of these compounds was able to enhance the postprandial GH 'paradoxical' response to GHRH in anorectic patients. The lack of effect of both groups postprandially also suggests a suppression of somatostatinergic activity.

Acetylcholinesterase↗
PubMed1996

Naloxone influence on the growth hormone, prolactin and thyrotropin response to thyrotropin releasing hormone in acromegalic patients.

In order to gain insight into the neuroendocrine mechanism underlying the paradoxical GH response to TRH in acromegalic patients, we have investigated the effect of an infusion of Naloxone (Nal, 1.6 mg/hr for two hours), on a TRH test performed both in responder (n = 9) and non-responder (n = 5) acromegalic patients. The response of GH, PRL and TSH to TRH injection were evaluated. NAL did not exert significant variations in the GH response, even if different patterns of GH response during NAL were observed in the group of TRH-responder patients. Similarly, TRH-induced PRL response was not significantly affected by the infusion of an opiate antagonist. On the contrary, a significant inhibition of the TSH response was observed in the group of TRH-responder patients (delta TSH after TRH 4.76 +/- 1.11 microU/ml, after NAL + TRH 2.81 +/- 0.99 microU/ml, p < 0.05). No significant effects were observed in the TRH non-responder patients (delta TSH after TRH 4.58 +/- 1.44 microU/ml, after NAL + TRH 6.26 +/- 3.27 microU/ml). The differences observed in the two groups of patients could be ascribed to a different endogenous somatostatinergic tone and could furnish a prognostic indication in acromegalic patients.

Acromegaly↗
PubMed1996

Effects of hypercholesterolemia of renal hemodynamics: study in patients with nephrotic syndrome.

Experimental and clinical studies have demonstrated a positive relationship between hyperlipidemia and rate of progression of renal disease, suggesting that lipids can induce or aggravate glomerular injury mainly by interacting with mesangial cells. Nevertheless, recently has been demonstrated that increased cholesterol levels can also induce endothelial cell dysfunction. Thus, since endothelium is known to play a major role in modulating the vascular tone, we have tested the possibility that hypercholesterolemia impairs the renal hemodynamics in patients with active nephrotic syndrome and elevated serum cholesterol levels. In this single-blind, nonrandom study, 12 patients were treated with pravastatin (group T, treated, n = 12) and 8 with placebo (group C, controls, n = 8). The controls were studied after the pravastatin group had been completed. Before starting the treatment the patients underwent basal determinations including routine laboratory investigations and PAH and inulin clearances. The same determinations were repeated after 48 h, and 6 and 12 weeks from the beginning of the treatment. The study at 48 h was performed to see if pravastatin had a direct, cholesterol-independent effect on renal function. The following basal results were reported (mean +/- SEM; group T vs. group C): serum cholesterol (mmol/l) 9.7 +/- 0.4 vs. 9.1 +/- 0.3 (NS); proteinuria (g/24 h): 6.2 +/- 0.2 vs. 7.0 +/- 0.7 (NS); PAH clearance (ml/min): 353 +/- 21 vs. 385 +/- 31 (NS); inulin clearance (ml/min): 62.5 +/- 7.7 vs. 67 +/- 9.3 (NS). After 48 h, no changes were observed in both groups. Subsequently, in group T, the following percentage changes of basal levels were observed: serum cholesterol -21.4 +/- 3.2% at 6 weeks (p < 0.05) and -34.9 +/- 3.2% at 12 weeks (p < 0.01); inulin clearance +3 +/- 3.7% at 6 weeks (NS) and +9.3 +/- 2.9% at 12 weeks (p < 0.05); PAH clearance +7 +/- 3.1% at 6 weeks (p < 0.05) and +21.2 +/- 5.5% at 12 weeks (p < 0.01). By contrast, no significant changes of these parameters occurred in group C at any time, so that the percent changes of baseline values of CPAH were significantly greater in group T (at 6 weeks: p < 0.05; at 12 weeks p < 0.005). These results indicate that the reduction of cholesterol is associated with a significant increase in renal plasma flow, thus, suggesting that hypercholesterolemia may actually impair the renal hemodynamics. We speculate that this effect may contribute to increase the risk of ischemic acute renal failure in nephrotic patients and, along with changes induced in the mesangium by other mechanisms, to contribute to the progression of renal disease.

Adult↗
PubMed1996

Serial morphometric analysis of sclerotic lesions in primary "focal" segmental glomerulosclerosis.

The possibility of missing the diagnosis of focal segmental glomerulosclerosis (FSGS) has been primarily attributed to the focal distribution of the sclerotic lesions, but this assumption has not been verified by any serial morphometric analysis of renal biopsy specimens. The aim of this study is to assess the size and the distribution of sclerotic lesions in primary FSGS and to establish the minimum number of glomeruli and sections necessary for the diagnosis. Fourteen biopsies from adult nephrotic patients with primary FSGS were carefully selected from a group of 41 biopsies, to minimize the possibility of finding and misinterpreting nonspecific glomerular scars, and were serially cut to obtain 1485 consecutive 2 microns-thick sections that, after PAS staining, showed 182 glomeruli. Fifty-seven glomeruli were "complete", i.e., they emerged after the first section and disappeared before the last section. The percentage of glomeruli with sclerotic lesions was 31.5% in the starting section, 71.8% after the observation of all serial sections, and 81.7% when only the complete glomeruli were considered. The morphometric analysis on complete glomeruli revealed that the volume of the sclerotic lesions averaged just 12.5% +/- 2.2 SE of the entire glomerular volume, and the statistical analysis revealed that the minimum number of glomeruli needed in the starting section to exclude sclerotic lesions is eight (P < 0.01) or nine (P < 0.001). If fewer glomeruli are seen, it is necessary to cut 2 microns-thick serial sections, but to examine just one of every 11 (P < 0.001), the number of sections to examine being proportional to the number of glomeruli found. In conclusion, this study shows that the distribution of sclerotic lesions in primary FSGS is not focal, but diffuse; however, because of the small size of the sclerotic lesions, the probability of missing the diagnosis is statistically relevant when fewer than eight glomeruli are found in the starting section, unless a serial morphological analysis, even on a reduced number of sections, is made.

Adult↗