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Biomedical subjects

E Toscano

Publications and source records attributed to E Toscano.

At least 19 recordsLinked to original sources

Down syndrome and breastfeeding.

AIM: The aim of the study was to investigate the frequency of breastfeeding among children with Down syndrome. METHODS: The mothers of 560 children with Down syndrome attending four university hospitals in Italy were interviewed and the neonatal clinical records retrieved. Information was collected on the type of infant feeding and on why some mothers had not breastfed their children. Two groups of healthy children whose feeding habits had been previously investigated were recruited as control subjects (1601 and 714, respectively). A paediatrician in each hospital was interviewed about the neonatal admission policy of children with Down syndrome. RESULTS: Among the 560 Down children, 246 (44%) were admitted to the neonatal unit. Compared with the two control groups, children with Down syndrome were significantly more frequently bottle-fed (57% vs 15% and 24%, respectively, odds ratio 7.5, 95% CI 6.0-9.4 and 4.2, 95% CI 3.3-5.4. respectively). Only 30% of infants admitted to the neonatal unit were breastfed. The main reasons reported by the mothers for not having breastfed were infants' illness in infants who had been admitted to the neonatal unit and frustration or depression, perceived milk insufficiency and difficulty with suckling for those babies who had not been admitted to the unit. The paediatricians reported that the admission of a baby with Down syndrome to the neonatal unit could sometimes take place not for medical reasons, but for diagnostic work-up or for a more appropriate diagnosis and to maintain communication with the family. CONCLUSIONS: Down syndrome babies are less frequently breastfed compared with healthy children. Support in breastfeeding should become a relevant point of health supervision for children with Down syndrome.

Bottle Feeding↗

Subclinical hypothyroidism and Down's syndrome; studies on myocardial structure and function.

BACKGROUND: The management of subclinical hypothyroidism (SH) is still controversial, as the benefit to risk ratio of prolonged L-thyroxine therapy is not clear cut. Some authors have shown abnormalities of myocardial function and structure in adults with SH, which could be reversed by L-thyroxine therapy. As SH frequently affects children with Down's syndrome (DS), and almost one half of these are affected by congenital heart disease, a concomitant SH related impairment of cardiac function might further compromise their clinical condition. AIMS: To establish whether SH influences myocardial structure and function in children with DS. METHODS: Sixteen children with DS and untreated SH and 25 matched euthyroid controls with DS underwent echocardiographic analysis of left ventricular mechanics and tissue characterisation. RESULTS: None of the 16 patients had myocardial impairment. CONCLUSION: Results suggest that children with DS who have SH are not at risk of cardiac disease. Clinicians should consider these data in the management of SH, as the benefit to risk ratio of prolonged L-thyroxine therapy is not clear cut.

Adolescent↗

Coincident linkage of fasting plasma insulin and blood pressure to chromosome 7q in hypertensive hispanic families.

BACKGROUND: Insulin resistance (IR) and hyperinsulinemia are phenotypically associated with hypertension. We have previously provided evidence that blood pressure (BP) and IR cosegregate in Hispanic families, suggesting that this association has a genetic component. In the present study, we provide further support for the hypothesis of a genetic basis for the BP-IR relationship from a genetic linkage study. METHODS AND RESULTS: A 10-cM genome scan was conducted in 390 Hispanic family members of 77 hypertensive probands. Detailed measurements of BP, glucose, insulin levels, and insulin sensitivity (euglycemic clamp) were performed in adult offspring of probands. Multipoint variance component linkage analysis was used. A region on chromosome 7q seemed to influence both IR and BP. The greatest evidence for linkage was found for fasting insulin (lod score=3.36 at 128 cM), followed by systolic BP (lod score=2.06 at 120 cM). Fine mapping with greater marker density in this region increased the maximum lod score for fasting insulin to 3.94 at 125 cM (P=0.00002); lod score for systolic BP was 2.51 at 112 cM. Coincident mapping at this locus also included insulin sensitivity measured by the homeostasis assessment model (HOMA) and serum leptin concentrations. Insulin sensitivity by euglycemic clamp did not map to the same locus. CONCLUSIONS: Our results demonstrate that a major gene determining fasting insulin is located on chromosome 7q. Linkage of BP, HOMA, and leptin levels to the same region suggests this locus may broadly influence traits associated with IR and supports a genetic basis for phenotypic associations in IR syndrome.

Adolescent↗

Evidence for joint genetic control of insulin sensitivity and systolic blood pressure in hispanic families with a hypertensive proband.

BACKGROUND: The clustering of hypertension, insulin resistance, and obesity remains unexplained. We tested for genetic and nongenetic influences on the association among these traits in Hispanic families with hypertension. METHODS AND RESULTS: Blood pressure and body mass index (BMI) were measured in 331 members of 73 Hispanic families in which an index case (proband) had hypertension. Insulin sensitivity (S(I)) was measured by euglycemic clamp in 287 probands and their spouses (parents' generation) or their adult offspring. Correlation analysis examined relationships among traits within and between generations. Path analysis estimated genetic and nongenetic contributions to variability in systolic blood pressure (SBP), S(I), and the correlation between them. In the offspring, there was a significant correlation between individuals for each trait, as well as significant correlations within and between individuals for all possible pairs of traits. Between generations, SBP, S(I), and BMI in parents correlated with the same traits in their offspring; BMI in parents correlated with S(I) and SBP in offspring; and S(I) in parents correlated with SBP in offspring. Path analysis estimated that among offspring, genetic effects unrelated to BMI accounted for 60.8% of the variation in SBP, 36.8% of the variation in S(I), and 31.5% of the correlation between SBP and S(I) after adjustment for age and sex. Heritable effects related to BMI accounted for an additional 14.0% of variation in SBP, 26.8% of variation in S(I), and 56.3% of variation in their correlation. CONCLUSIONS: Clustering of hypertension and insulin resistance in Hispanic Americans is accounted for in part by heritable factors both associated with and independent of BMI.

Adolescent↗

Congenital insensitivity to pain with anhidrosis (CIPA): novel mutations of the TRKA (NTRK1) gene, a putative uniparental disomy, and a linkage of the mutant TRKA and PKLR genes in a family with CIPA and pyruvate kinase deficiency.

Congenital insensitivity to pain with anhidrosis is an autosomal recessive hereditary disorder characterized by recurrent episodic fever, anhidrosis (inability to sweat), absence of reaction to noxious stimuli, self-mutilating behavior, and mental retardation. The human TRKA gene (NTRK1), located on chromosome 1q21-q22 encodes the receptor tyrosine kinase for nerve growth factor. We reported that TRKA is the gene responsible for CIPA and we developed a comprehensive strategy to screen for TRKA mutations and polymorphisms, as based on the gene's structure and organization. Here we report eight novel mutations detected as either a homozygous or heterozygous state in nine CIPA families from five countries. Mendelian inheritance of the mutations was confirmed in seven families for which samples from either parent were available. However, non-mendelian inheritance seems likely for the family when only samples from the mother and siblings, (but not from the father) were available. A paternal uniparental disomy for chromosome 1 is likely to be the cause of reduction to homozygosity of the TRKA gene mutation in this family. Interestingly, a Hispanic patient from the USA has two autosomal genetic disorders, CIPA and pyruvate kinase deficiency, whose genetic loci are both mapped to a closely linked chromosomal region. A splice mutation and a missense mutation were detected in the TRKA and PKLR genes from the homozygous proband, respectively. Thus, concomitant occurrence of two disorders is ascribed to a combination of two separate mutant genes, not a contiguous gene syndrome. This finding suggests a mechanism responsible for two autosomal genetic disorders in one patient. All these data further support findings that TRKA defects can cause CIPA in various ethnic groups. This will aid in diagnosis and genetic counseling of this painless but severe genetic disorder.

Adolescent↗

Cholelithiasis in Down's syndrome.

Cholelithiasis is considered uncommon in infancy, childhood, and adolescence. We performed a prospective, controlled study showing that children with Down's syndrome have a significantly higher prevalence of cholelithiasis (4.7%) compared with controls (0.2%). Clinicians should be aware of the risk of gallstones in children with Down's syndrome.

Adolescent↗

Multisystem involvement in congenital insensitivity to pain with anhidrosis (CIPA), a nerve growth factor receptor(Trk A)-related disorder.

Congenital insensitivity to pain with anhidrosis (CIPA), a rare autosomal recessive disorder, is characterized by insensitivity to pain, self-mutilating behaviour, anhidrosis and recurrent hyperpyrexia. It is a hereditary sensory and autonomic neuropathy, also classified as HSAN, due to a defect of the receptor for nerve growth factor. CIPA is the first human genetic disorder caused by a defect in the neurotrophin signal transduction system. This is the first clinical report of CIPA patients characterized on molecular grounds. The clinical phenotypes of our patients show that CIPA is characterized by a multisystem involvement besides the nervous system, including bone fracture with slow healing, immunologic abnormalities, such as low response to specific stimuli, chronic inflammatory state ending in systemic amyloidosis. The molecular characterization allows a better understanding of most of the clinical features.

Abnormalities, Multiple↗

Pharmacological characteristics and regulation of 5-HT receptor-stimulated phosphoinositide hydrolysis in the rat spinal cord.

In slices from immature rat spinal cord, both 5-hydroxytryptamine (5-HT) and the 5-HT2A/C receptor agonists (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and alpha-methyl-5-HT (alpha-Me-5-HT) stimulate phosphoinositide (PI) hydrolysis. PI breakdown is also increased by the 5-HT3 receptor agonist 2-Me-5-HT but not by phenylbiguanide. The effect of either 5-HT or DOI is blocked by selective 5-HT2A receptor antagonists such as spiperone and ketanserin and more markedly by mixed 5-HT2 receptor antagonists, such as ritanserin, methysergide and mesulergine, with higher affinity at the 2C subtype. The effect of 2-Me-5-HT is blocked by 5-HT2 and not by 5-HT3 receptor antagonists, indicating that 5-HT3 receptors do not directly or indirectly take part in PI hydrolysis in the spinal cord. Moreover, lesion with neonatal capsaicin of thin primary afferents to the dorsal spinal cord enhances inositol phosphate formation stimulated by 5-HT or DOI but not by 2-Me-5-HT. This lesion also increases 5-HT2A and 5-HT2C receptor density. After neonatal injection of 5,7-dihydroxytryptamine, which results in a marked loss of 5-HT content in the cord, 5-HT and 5-HT2 receptor agonists also enhance PI breakdown without a concomitant change in receptor number. The results suggest that the 5-HT-stimulated PI response in the rat spinal cord is associated only with the 5-HT2 receptor class, in particular with the 5-HT2C subtype.

5,7-Dihydroxytryptamine↗

Congenital insensitivity to pain with anhidrosis: novel mutations in the TRKA (NTRK1) gene encoding a high-affinity receptor for nerve growth factor.

Congenital insensitivity to pain with anhidrosis (CIPA) is characterized by recurrent episodes of unexplained fever, anhidrosis (inability to sweat), absence of reaction to noxious stimuli, self-mutilating behavior, and mental retardation. Human TRKA encodes a high-affinity tyrosine kinase receptor for nerve growth factor (NGF), a member of the neurotrophin family that induces neurite outgrowth and promotes survival of embryonic sensory and sympathetic neurons. We have recently demonstrated that TRKA is responsible for CIPA by identifying three mutations in a region encoding the intracellular tyrosine kinase domain of TRKA in one Ecuadorian and three Japanese families. We have developed a comprehensive strategy to screen for TRKA mutations, on the basis of the gene's structure and organization. Here we report 11 novel mutations, in seven affected families. These are six missense mutations, two frameshift mutations, one nonsense mutation, and two splice-site mutations. Mendelian inheritance of the mutations is confirmed in six families for which parent samples are available. Two mutations are linked, on the same chromosome, to Arg85Ser and to His598Tyr;Gly607Val, hence, they probably represent double and triple mutations. The mutations are distributed in an extracellular domain, involved in NGF binding, as well as the intracellular signal-transduction domain. These data suggest that TRKA defects cause CIPA in various ethnic groups.

Base Sequence↗

Absence of testicular DAZ gene expression in idiopathic severe testiculopathies.

Deletions of the DAZ (deleted in azoospermia) gene family are frequently responsible for male infertility and are generally assessed by analyses of genomic DNA extracted from peripheral leukocytes. The multicopy nature of this gene prevents the distinction of intragenic deletions or deletions not involving the whole DAZ gene cluster. Thus it is still unclear whether each DAZ copy is effectively expressed in the testis. We analysed, by reverse transcription-polymerase chain reaction (RT-PCR), the expression of DAZ, RBM and SRY genes, in testicular cells from infertile men affected by idiopathic severe hypospermatogenesis, obstructive azoospermia and Sertoli cell-only syndrome. Normal mRNA for DAZ, RBM and SRY were observed in obstructive azoospermia, whereas only SRY transcripts were detected when only Sertoli cells were present. Nine out of 10 patients affected by idiopathic severe hypospermatogenesis had normal expression of SRY, RBM and DAZ, while in one patient no DAZ transcript was detected, suggesting that his testiculopathy was related to the absence of DAZ expression. The lack of DAZ mRNA in testicular cells with an apparently normal DAZ gene constitution on DNA extracted from leukocytes may be explained by different hypotheses: (i) not all the copies of the DAZ gene cluster are transcribed in the germ cells and the reported patient had a small deletion involving only the active ones; (ii) the patient may be mosaic for the DAZ gene having a normal constitution in leukocytes and be deleted for DAZ gene in the testis; (iii) abnormalities of DAZ transcription may exist. These findings highlight the intrinsic interpretative difficulties of normal PCR analysis for DAZ and RBM on leukocytes and suggest caution in the use of germ cells for assisted reproductive techniques in these cases to avoid transmission of genetic abnormalities to male offspring.

Biopsy, Needle↗

Detection of subclinical central nervous system abnormalities in two patients with mucolipidosis III by the use of motor and somatosensory evoked potentials.

We have studied motor, somatosensory, brainstem auditory and visual evoked potentials in two patients with ML III without overt neurologic symptoms. Both our patients showed abnormal central motor functions upon magnetic cortical stimulation; in addition, in one of them, we observed a decreased conduction velocity of the nervous impulse in the central tract of the upper limb somatosensory pathway, from the cervical spinal cord to sensory cortex. Our results suggest that central motor pathways are affected in both children and also that the central somatosensory system is involved in one of them. We propose that the electrophysiological techniques might be of help to detect, locate and monitor minimal neurological lesions of mild lysosomal disorders like ML III.

Central Nervous System Diseases↗

Effect of prenatal exposure to antidepressants on 5-HT-stimulated phosphoinositide hydrolysis and 5-HT2 receptors in rat brain.

1. Female rats were given antidepressants, with different effects on 5-HT uptake, from day 6 of pregnancy until delivery. 2. 5-HT-stimulated inositol phosphate accumulation as well as 5-HT2 receptor density were measured at two different times in the pups. 3. Prenatal exposure to fluoxetine or iprindole reduced phosphoinositide hydrolysis in 25-day-old pups. However, chronic treatment of adult rats with fluoxetine or prenatal exposure to either desipramine or tianeptine did not modify inositol phosphate accumulation. 4. After prenatal exposure, only desipramine significantly decreased the density of [3H]ketanserin-labelled 5-HT2 receptors in the pups. 5. No correlation was found between changes in inositol phosphate formation and 5-HT2 receptor number.

Animals↗

Infection and apparent invasion of Vero cells by Paracoccidioides brasiliensis.

Paracoccidioides brasiliensis probably uses many different mechanisms to establish itself in the host and cause disease. In this work, we assess an in vitro model system which uses cultured mammalian cells to investigate the virulence factors of P. brasiliensis. We were able to demonstrate an invasion process of the yeast form of this fungus in Vero cell cultures. We deduced that the overall invasive process involved three steps: adhesion, followed by invasion of individual epithelial cells and spread to adjacent cells.

Animals↗

Effect of prenatal exposure to tianeptine on different neurotransmitter receptors and 5-HT-stimulated inositol phosphate formation in rat brain.

Tianeptine, an antidepressant drug enhancing 5-HT uptake, was given to pregnant rats in the last 15 days of gestation and different neurotransmitter receptors as well as 5-HT2 receptor-linked inositol phosphate formation were measured in the brains of the offspring. Prenatal exposure to tianeptine significantly decreased the density of 3H-imipramine binding sites in the cerebral cortex of the pups without affecting beta-adrenoceptors, serotonin 5-HT2 and 5-HT1B receptors or inositol phosphate formation after a 5-HT challenge. Striatal dopamine D2 receptors labelled with 3H-spiroperidol were not changed but an apparent increase in the affinity of dopamine was noticed in the pups prenatally exposed to the drug. The results show that the neurochemical profile of tianeptine markedly differs from that of most antidepressants.

Animals↗