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Biomedical subjects

E Riva

Publications and source records attributed to E Riva.

At least 73 records · Page 4Linked to original sources

Cardiac effects of angiotensin I and angiotensin II: dose-response studies in the isolated perfused rat heart.

We investigated the effects of angiotensin I (4 x 10(-9), 4 x 10(-8) and 4 x 10(-7) M) on myocardial contractility, heart rate and coronary perfusion in the isolated rat heart before and after inhibition of angiotensin-converting enzyme (ACE) by captopril (4 x 10(-4) M). We also studied the post-ischaemic recovery of cardiac function in isolated hearts subjected to global myocardial ischaemia and reperfused with various doses of angiotensin II (1 x 10(-9), 1 x 10(-8) and 1 x 10(-7) M). Angiotensin I significantly reduced coronary flow, the vasoconstrictor effect of a second identical dose was attenuated after inhibition of ACE with captopril. Angiotensin II reduced coronary flow to the same extent as angiotensin I at a concentration four times lower. Left ventricular developed pressure was reduced by angiotensin I and angiotensin II in a dose-dependent manner. Heart rate was not affected by angiotensin I and was significantly lowered by the highest doses (1 x 10(-8) and 1 x 10(-7) M) of angiotensin II. Post-ischaemic recoveries of vascular and contractile function were similar in control hearts and in hearts given angiotensin II during reperfusion. However, left ventricular end-diastolic pressure was increased by the highest dose (1 x 10(-7) M) of angiotensin II throughout reperfusion compared with controls or hearts receiving lower doses (NS). In conclusion the attenuated vasoconstrictor response to angiotensin I after captopril pre-treatment confirms the existence of an intracardiac renin-angiotensin system operative in vitro. Our results also suggest that angiotensin II, at a high concentration, may play a negative role in relaxation in the ischaemic-reperfused injured heart.

Angiotensin I↗

Changes in diastolic function and collagen content in normotensive and hypertensive rats with long-term streptozotocin-induced diabetes.

We investigated the relationship between left ventricular diastolic function and interstitial collagen content in the endocardium, mesocardium and epicardium of transverse sections of the heart, using an image analysis system in normotensive and hypertensive long-term streptozotocin (STZ) diabetic rats. STZ-induced diabetes was characterised by elevated blood glucose, polyuria, polydypsia and loss of body weight. In vivo systolic blood pressure was 165 +/- 4, 136 +/- 3 and 129 +/- 7 mmHg in hypertensive and normotensive diabetic rats and age-matched controls, respectively. Heart rate was significantly lower (P < 0.01) in diabetic rats (283 +/- 8 and 280 +/- 10 beats min-1 in normotensive and hypertensive rats, respectively) than controls (393 +/- 18 beats min-1). Pressure-volume (P-V) curves were studied in isolated Langendorff perfused hearts at rest and after 20 min global ischaemia and 30 min reperfusion 6 months after induction of diabetes. Left ventricular volumes were significantly smaller in diabetic rats than age-matched controls, but volumes normalised for heart weight were higher in normotensive (by 28%) and hypertensive (by 10%) diabetic rats. Slopes of end-diastolic P-V curves were similar between groups in basal conditions, but left ventricular systolic P-V curves were steeper in normotensive and flatter in hypertensive diabetic hearts. Post-ischaemic left ventricular end-diastolic pressure was significantly higher than the pre-ischaemic value at comparable increments of volume in each group. Collagen content significantly increased in the heart of rats with STZ-diabetes both in the free left ventricular wall and septum, and suggested this may play a role in the cardiac defects in contractility and relaxation in our experimental conditions. These results indicate that diabetes, irrespective of associated hypertension, can cause major changes in cardiac performance and susceptibility to ischaemia and reperfusion.

Animals↗

Anthropometric indicators of human immunodeficiency virus infection in infants with early and late symptoms in the first months of life.

UNLABELLED: Standardised growth indices (Z-scores of weight-for-age, WA, length-for-age, LA, weight-for-length, WL, according to the reference data of the World Health Organization) have been compared for the first 4 months of life among 119 infants born to mothers affected by the type-1 human immunodeficiency virus (HIV). Infants were subdivided according to their HIV serostatus and the clinical expression of the disease. Uninfected status (n = 92), late (>6 months, n = 18) and early (<3 months, n = 9) onset of symptoms among the HIV infected defined three groups. Infants with early symptoms showed the lowest median WA and LA Z-scores at all times and the LA difference with their uninfected counterparts was already significant at birth. Infants with late symptoms showed early differences in WL and then in WA also compared with the uninfected ones. A < -0.40 LA Z-score at birth gave a 5.9 relative risk (RR) to be an infant with early symptoms (95% CI = 1.2-27.4) while a negative WL Z-score at 2 months of age gave a 4.2 RR for the HIV seropositivity (95% CI = 2.1-8.3). CONCLUSION: Linear growth is the first parameter to be negatively affected among human immunodeficiency virus seropositive infants with early symptoms. In infants with late symptoms the lack of rapid WA and WL increase found among uninfected patients may be viewed as an early anthropometric indicator of HIV status.

Age Factors↗

The role of dietary polyunsaturated fatty acids during the first 2 years of life.

The early dietary supply of long-chain polyunsaturated fatty acids (LCPUFA) might contribute to the higher developmental scores of children breast-fed as infants. Preterm infants' improved visual acuity and neurodevelopmental performance correlate with dietary supplementation of LCPUFA in amounts similar to those that breast-fed infants receive and studies of term infants report similar effects with LCPUFA supplementation. Whether term infants may benefit from LCPUFA-unsupplemented formulas with higher amounts of alpha-linolenic acid (n - 3 LCPUFA precursor) is controversial. With the onset of weaning, the question of the exact quantity and quality of which dietary lipids to give for prevention purposes is still open. Early dietary intervention studies of weaned children under 2 years are in progress in populations at high risk for early cardiovascular disorders. Preliminary results indicate that these interventions, while preventing an age-dependent increase in blood lipid levels, are safe for growth, but the balance of all the macronutrients should be carefully considered before general recommendations can be made.

Child Nutritional Physiological Phenomena↗

Dietary fatty acids and cholesterol in the first 2 years of life.

Both long-chain polyunsaturated (LCP) fatty acids and cholesterol are supplied by human milk. Dietary long-chain polyunsaturated fatty acids in the first 2 years of life have been associated with growth and developmental indices. Cholesterol supply does not seem relevant for structural purposes, but could have a role in the metabolism of LCP. Complex relationships between dietary fatty acids and cholesterol seem to be major determinants of blood lipid levels in the first months of life. Data from both suckling and weaned infants indicate that their blood lipid profile reacts to changes in their diet in a manner similar to adults. Early intervention trials on weaned infants (<2 years of age) have been addressed in populations at high risk for early cardiovascular disorders and seem safe for growth at short-term assessments, but the balance of all the macronutrients should be carefully considered. While the effects of plasma cholesterol concentrations in the suckling infant on the subsequent development of atheroslerosis are still unknown, both the diet composition and the way by which food is supplied to infants seem to be major determinants of their metabolic profile.

Arteriosclerosis↗

Low levels of linoleic acid in plasma total lipids of HIV-1 seropositive children.

OBJECTIVE: To assess the plasma fatty acid status of a group of well-nourished children with the human immunodeficiency virus type-1 (HIV-1) and how this relates to the blood total CD4+ lymphocyte count. SUBJECTS: Fourteen HIV-1 seropositive children at various stages of disease and with adequate growth indices were assessed and compared to a control group of 30 healthy children. RESULTS: The concentrations (mg/dL) of plasma total fatty acids were not different between the two groups. HIV-1 seropositive children presented lower levels of 18-C essential polyunsaturated fatty acids (PUFA: linoleic acid, LA, and alpha-linolenic acid) and higher levels of their 20-C long-chain derivatives (di-homo-gamma-linolenic acid, arachidonic acid, AA, and eicosapentaenoic acid) and docosahexaenoic acid in their plasma total lipids. The lowest plasma LA levels were observed in the subgroup of patients with more advanced stages of disease. In bivariate analyses the plasma LA levels related positively (Spearman r = 0.50, p = 0.06), while the LA/AA ratio related negatively (Spearman r = -0.51, p = 0.06), to the total CD4+ count. CONCLUSIONS: Childhood HIV-1 infection is associated with changes in plasma fatty acid profile suggestive of an increased PUFA turnover. Decreased levels of LA (together with higher plasma AA levels) appear to be associated with more advanced clinical and biochemical stages of disease.

8,11,14-Eicosatrienoic Acid↗

Body mass index development during the first 6 months of life in infants born to human immunodeficiency virus-seropositive mothers.

The development of body mass index (BMI) was measured during the first 6 months of life in three groups of infants [human immunodeficiency virus (HIV) -uninfected, n = 92; later symptomatic HIV-infected, n = 18; early symptomatic HIV-infected, n = 9] born to HIV-positive mothers and compared with a reference group (n = 65) born to healthy mothers. A trend towards lower values in the two groups of HIV-infected infants was already evident at birth. Among the four groups, HIV-uninfected infants showed the highest BMI values while the early-infected infants showed the lowest BMI values at all measurements. The later-infected group had a value close to the reference at 1 month, and then increased at slower rates than the uninfected and the reference groups. Infants born to HIV-positive mothers may have higher energy and nutrient requirements after birth, either to sustain an increased BMI development (when uninfected) or to meet catabolic mechanisms (when infected).

Body Mass Index↗

A European multicenter study of phenylalanine hydroxylase deficiency: classification of 105 mutations and a general system for genotype-based prediction of metabolic phenotype.

Phenylketonuria (PKU) and mild hyperphenylalaninemia (MHP) are allelic disorders caused by mutations in the gene encoding phenylalanine hydroxylase (PAH). Previous studies have suggested that the highly variable metabolic phenotypes of PAH deficiency correlate with PAH genotypes. We identified both causative mutations in 686 patients from seven European centers. On the basis of the phenotypic characteristics of 297 functionally hemizygous patients, 105 of the mutations were assigned to one of four arbitrary phenotype categories. We proposed and tested a simple model for correlation between genotype and phenotypic outcome. The observed phenotype matched the predicted phenotype in 79% of the cases, and in only 5 of 184 patients was the observed phenotype more than one category away from that expected. Among the seven contributing centers, the proportion of patients for whom the observed phenotype did not match the predicted phenotype was 4%-23% (P<.0001), suggesting that differences in methods used for mutation detection or phenotype classification may account for a considerable proportion of genotype-phenotype inconsistencies. Our data indicate that the PAH-mutation genotype is the main determinant of metabolic phenotype in most patients with PAH deficiency. In the present study, the classification of 105 PAH mutations may allow the prediction of the biochemical phenotype in >10,000 genotypes, which may be useful for the management of hyperphenylalaninemia in newborns.

Alleles↗

Heat treatment modifies the allergenicity of beef and bovine serum albumin.

The effect of heat on the allergenicity of beef and bovine serum albumin was investigated among 10 toddlers skin prick test (SPT)-positive to raw and cooked beef. The meat-allergy diagnosis was confirmed during double-blind, placebo-controlled food challenge (DBPCFC) with 180 g of beef cooked for 5 min at 100 degrees C. SPT with homogenized and freeze-dried beef, and heated and unheated bovine serum albumin were performed. Both heated and unheated bovine serum albumin, homogenized beef, and freeze-dried beef were used in trial DBPCFC. All children were SPT-positive to unheated bovine serum albumin. Seven were positive to heated bovine serum albumin, one to freeze-dried beef, and none to homogenized beef. DBPCFCs were negative for homogenized beef and freeze-dried beef, positive for unheated bovine serum albumin in five patients, and positive for heated albumin in four children. We conclude that heating reduces sensitization to beef and bovine serum albumin but does not abolish reactivity to albumin under home conditions. However, industrially heat-treated and sterilized homogenized beef and freeze-dried beef may be suitable substitutes in beef-allergic children's diets.

Allergens↗

Growth in the first two years of uninfected children born to HIV-1 seropositive mothers.

OBJECTIVE: To assess the growth curves of uninfected infants born to type 1 human immunodeficiency virus (HIV-1) seropositive mothers by means of standardised anthropometric indices. METHODS: The z scores (National Center for Health Statistics-World Health Organization data) of weight for age, length for age, and weight for length of 92 uninfected full term infants born to HIV positive mothers were compared with those of 65 bottle fed full term infants born to healthy mothers at 0, 1, 2, 3, 4, 6, 9, 12, 18, and (in a subgroup) 24 months of age. Confounders were also recorded. RESULTS: The study population had a lower length for age z score at birth (95% confidence intervals (CI): 0.02, -0.58) and higher weight for length z scores at 1 (95% CI: 0.21, 0.63), 2 (95% CI: 0.25, 0.66), and 3 (95% CI: 0.0, 0.48) months compared with the reference group. After a temporary recovery, the length for age z score difference increased progressively from the 4th month onwards and was significant at 18 (95% CI: -0.31, -1.05) and 24 (95% CI: -0.02, -0.91) months. The difference between the length for age z scores at birth was associated with maternal covariates, but the between group difference at 18 months was apparent even after adjustment for covariates. CONCLUSION: Uninfected infants born to HIV positive mothers have a rapid weight gain immediately after birth. A decrease in length progression during the second year might be a result of the social risk connected with the family environment and an unfavourable programming related to the maternal HIV status.

Body Height↗

Plasma arachidonic acid and serum thromboxane B2 concentrations in phenylketonuric children are correlated with dietary compliance.

Phenylketonurics display lower arachidonic acid levels in plasma lipids, reflecting the lower intake due to the dietary treatment poor in phenylalanine-rich animal foods. Plasma arachidonic acid levels and serum thromboxane B2 concentrations have been measured in 13 treated phenylketonuric children and compared with those of 12 healthy controls. A direct relationship between plasma arachidonic acid and thromboxane B2 concentrations has been observed only in phenylketonurics, whose plasma arachidonic acid status correlated negatively with their dietary compliance. These results suggest that the low consumption of animal fats may contribute to modulate the production of arachidonic acid-derived platelet eicosanoids.

Adolescent↗

["Judicious" use of neuroleptic drugs in the treatment of behavioral symptoms in the course of Alzheimer disease].

It is estimated that about one-half of Alzheimer's patients develop psychotic and/or behavioural signs and symptoms which can cause the most distress and difficulties to families and healthcare professionals. The prevalence and the type of problem behaviours varies remarkably with the course of Alzheimer's disease, the severity of cognitive impairment, the neuropathology and biochemical changes. The prevalence varies also in relation to the setting, sample size, rating instruments for assessment, comorbidity, coexistence of different problem behaviours and pharmacological therapies. Neuroleptics are the only documented pharmacological treatment for psychosis, agitation, suspicion, delusions and hallucinations. Neuroleptics have a number of potentially severe adverse effects, that caution against their widespread use in elderly patients. High potency agents such as haloperidol are more likely to cause Parkinsonian symptoms, while low-potency agents such as thioridazine and chlorpromazine are more likely to cause sedation, confusion, delirium, postural hypotension and peripheral anticholinergic effects. The new antipsychotic agents (atypical neuroleptics) such as risperidone, clozapine and olanzapine appear to have efficacy either superior to the traditional neuroleptics or are generally comparable with fewer side-effects. These results however refer to clinical studies in patients with schizophrenia and they have not yet been tested with demented population in well controlled trials.

Alzheimer Disease↗

Two novel PAH gene mutations detected in Italian phenylketonuric patients.

We report the identification by denaturing gradient gel electrophoresis and sequence analysis of two new phenylalanine hydroxylase (PAH) gene mutations (IVS4nt-2 and N207S) in single chromosomes of two unrelated Italian phenylketonuric (PKU) patients. Interestingly, mutation Y204C, found on the second mutant allele of family F1, has been previously detected in Chinese patients. Haplotype analysis showed that the latter mutation is linked to the same haplotype (H4) in both Chinese and Italian patients, suggesting a common origin. In vivo assessment of mutation severity indicates that N207S is associated with classic PKU. The identification of these two new mutations further extends the remarkable heterogeneity of the PAH locus in the Italian population.

Child↗

Plasma arachidonic acid and serum thromboxane B2 concentrations in phenylketonuric children negatively correlate with dietary compliance.

The study addresses the relationship of plasma arachidonic acid and thromboxane production with the dietary compliance in treated phenylketonuric patients, whose vegan-like dietary pattern makes them a useful model to evaluate the effects of the near-total avoidance of animal fats. Thirteen treated phenylketonuric children were compared with twelve healthy controls for arachidonic acid intake, plasma fatty acids and platelet thromboxane B2 production, assessed as accumulation of this eicosanoid in serum. The calculated intake of arachidonic acid was lower in phenylketonurics than in controls and this was associated with lower levels in plasma lipids. Plasma arachidonic acid concentrations and serum thromboxane B2 levels correlated with the last 12 months phenylalanine levels, taken as negative indicator of dietary compliance. A direct relationship between plasma arachidonic acid concentration and thromboxane B2 production was observed only in phenylketonuric patients (r = 0.74, P = 0.01). While well-compliant PKU subjects have low arachidonic acid and thromboxane concentrations in plasma, the low compliance with animal food avoidance, evoking higher phenylalanine levels, results in elevation of both plasma arachidonic acid and serum thromboxane B2. This gives support to the hypothesis that the consumption of animal fats may affect the production of arachidonic acid-derived platelet eicosanoids.

Adolescent↗

Effect of nedocromil sodium on bronchial hyperreactivity in children with nonatopic asthma.

BACKGROUND AND OBJECTIVES: Although cromones inhibit immediate bronchial responses to both allergen and nonspecific challenge, their effectiveness in treating nonatopic childhood asthma is unknown. We therefore investigated a possible effect of nedocromil sodium on bronchial hyperreactivity and asthmatic symptoms in a group of children receiving this drug for nonatopic asthma. STUDY DESIGN AND METHODS: A double-blind, placebo-controlled, randomized trial of two parallel groups was carried out in our pediatric respiratory disease clinic. Twenty children with mild, nonatopic asthma hyperreactive to fog-induced challenge were treated with inhaled nedocromil sodium 16 mg each day for 6 weeks (group N) or with a placebo (group P). Five girls and five boys (7 to 13 years of age) were randomly assigned to group N, and three girls and seven boys (aged 6 to 16 years) to group P. Symptoms and bronchodilator use were reported on diary cards. Ultrasonic nebulized distilled water PD10 was measured administering increasing doses of nebulized distilled water (2.5, 5, 10, 20, and 40 L). RESULTS: Symptom scores were significantly affected by the active treatment. Baseline lung function was normal and remained unaltered after treatment with nedocromil sodium. Nonspecific reactivity was significantly reduced over time only in the active treatment group. CONCLUSIONS: Nedocromil sodium can reduce the severity of asthmatic symptoms and nonspecific bronchial hyperreactivity at fog-induced challenge in children with stable, nonatopic asthma.

Adolescent↗