Subclinical hypothyroidism and myocardial function in obese children.

BACKGROUND AND AIMS: Pediatric obesity is an important health problem representing a major public health concern worldwide in the last decades. An isolated elevation of Thyroid Stimulating Hormone (TSH) with normal levels of thyroid hormones is frequently found in obese children. It has been named Isolated Hyperthyreotropinemia or Subclinical Hypothyroidism (SCH) and may be considered a consequence of obesity. Evidence exists that SCH is related to impairment of both systolic and diastolic myocardial function in the adult population. The aim of our study is to establish if obesity-related SCH influences myocardial function in children. METHODS AND RESULTS: We examined 34 obese children and adolescents with SCH and 60 obese children with normal TSH levels who underwent Doppler echocardiographic to evaluate myocardial function. Global systolic function as assessed by Ejection Fraction (EF) was comparable between groups, however Right Ventricle pressure global systolic function and pressure were significantly reduced in SCH group. Mitral annulus peak systolic (MAPSE) excursion lateral and MAPSE septum resulted significantly reduced in SCH group. Tissue Doppler imaging peak systolic motion (TDI-S) was reduced in SCH group. Diastolic function also showed significant modifications in SCH group. CONCLUSION: These results suggest possible involvement of cardiac function in obese children with SCH resulting in both abnormal diastolic function and reduced longitudinal systolic function. This new insight into cardiovascular consequences of obesity-related SCH in children could influence clinical approach to such patients by pediatric endocrinologists.

The insulin gene variable number of tandemrepeats (INS VNTR) genotype and sleep disordered breathing in childhood obesity.

Aim of our study is to verify the association between the genetic predisposition to hyperinsulinism due to the presence of the insulin gene (INS) I/I genotype and the development of sleep-related breathing disorders (SRBD) in obese children and adolescents. Two hundred and fifty-six obese children and adolescents (125 girls) have been investigated. As initial screening all subjects' mothers filled out the Sleep Disturbances Scale for Children (SDSC). The Sleep-Disordered Breathing (SDB) scale has been taken into account. Successively, a subgroup of 34 patients belonging to the first (14 children) and the last (20 children) SDB score quintiles underwent an overnight polysomnography and the apnea-hypopnea index (AHI) was evaluated. All subjects were genotyped for the INS VNTR and fasting insulin levels were evaluated. The population was divided into two groups according to the genotype: the first group was comprehensive of patients homozygotes for class I allele and the second group was composed by class III allele heterozygotes and homozygotes patients. Subjects I/I showed statistically signifIcant higher insulin levels (p<0.001) and SDB scores (p<0.001). Moreover, in the subgroup of patients investigated with polysomnography, class I homozygous subjects showed higher AHI compared to those patients carrying class III allele (p<0.001). Our data support the hypothesis that INS VNTR is associated with the development of SDB among obese children and adolescents.

Microsporogenesis in Brachiaria dictyoneura (Fig. & De Not.) Stapf (Poaceae: Paniceae).

Microsporogenesis was analyzed in five accessions of Brachiaria dictyoneura presenting x = 6 as the basic chromosome number. All accessions were tetraploid (2n = 4x = 24) with chromosome pairing in bi-, tri-, and quadrivalents. The recorded meiotic abnormalities were those typical of polyploids, including precocious chromosome migration to the poles, laggard chromosomes, and micronucleus formation. The frequency of these abnormalities, however, was lower than those reported for other polyploid accessions previously analyzed for other Brachiaria species. Cell fusion and absence of cytokinesis were also recorded in some accessions, leading to restitutional nucleus formation in some cells. Genetically unbalanced microspores, binucleate, and 2n microspores were found among normal meiotic products as results from these abnormalities. The limitation in using these accessions as pollen donor in interspecific crosses with sexual species with x = 7 or x = 9 in breeding programs is discussed.

Evidence of allopolyploidy in Brachiaria brizantha (Poaceae: Paniceae) through chromosome arrangement at metaphase plate during microsporogenesis.

In the hexaploid (2n = 6x = 54) accession B176 of Brachiaria brizantha, one cytological characteristic differentiated it from the other accessions previously analyzed with the same ploidy level. Nearly 40% of meiocytes displayed the chromosome set arranged at two metaphase plates at the poles of the cell, close to the membrane. In these cells, both metaphase plates were arranged in an angle to form a typical tripolar spindle. Therefore, cells did not show normal chromosome segregation at anaphase I. Only nine univalent chromosomes migrated from each plate to the opposite pole with the remainder staying immobile on the plate. As a result of such spindle orientation and chromosome behavior, trinucleate telophases I were recorded. After telophase, cytokinesis eliminated the small nuclei into a microcyte. The second division proceeded normally, with the presence of microcytes in all phases. The origin of such an abnormality was explained on the hexaploid level of the accession which could have resulted by chromosome doubling of a triploid derived from species that did not display the same behavior for spindle organization. The high percentage of meiotic abnormalities recorded in this accession compromises fertility and renders it inadequate for the breeding program.

Symmetric pollen mitosis I and suppression of pollen mitosis II prevent pollen development in Brachiaria jubata (Gramineae).

Microsporogenesis and pollen development were analyzed in a tetraploid (2n = 4x = 36) accession of the forage grass Brachiaria jubata (BRA 007820) from the Embrapa Beef Cattle Brachiaria collection that showed partial male sterility. Microsporocytes and pollen grains were prepared by squashing and staining with 0.5% propionic carmine. The meiotic process was typical of polyploids, with precocious chromosome migration to the poles and laggards in both meiosis I and II, resulting in tetrads with micronuclei in some microspores. After callose dissolution, microspores were released into the anther locule and appeared to be normal. Although each microspore initiated its differentiation into a pollen grain, in 11.1% of them nucleus polarization was not observed, i.e., pollen mitosis I was symmetric and the typical hemispherical cell plate was not detected. After a central cytokinesis, two equal-sized cells showing equal chromatin condensation and the same nuclear shape and size were formed. Generative cells and vegetative cells could not be distinguished. These cells did not undergo the second pollen mitosis and after completion of pollen wall synthesis each gave rise to a sterile and uninucleate pollen grain. The frequency of abnormal pollen mitosis varied among flowers and also among inflorescences. All plants were equally affected. The absence of fertile sperm cells in a considerable amount of pollen grains in this accession of B. jubata may compromise its use in breeding and could explain, at least in part, why seed production is low when compared with the amount of flowers per raceme.

[Cystic lymphangioma of the abdominal wall in childhood: case report]. / Linfangioma cistico della parete addominale in età pediatrica. Caso clinico.

Intra-abdominal lymphangiomas are rare benign tumours that can cause various symptoms, mainly during childhood. They are diagnosed by ultrasonography, CT scanning or at laparotomy; ultrasonographic examination often shows a voluminous tumoral cystic formation with septa. The location of the cyst may be determined either by ultrasonography alone or by CT scanning. The definitive histological diagnosis is confirmed by immunohistochemical staining techniques. Rarely intra-abdominal lymphangiomas can occur in the abdominal wall. Complete resection is the treatment of choice. The case of a 2-year-old-boy with a large lymphangioma involving the lower half of the abdominal wall is reported. The patient underwent the complete removal of lymphangioma with good cosmetic result.

Asynchronous meiotic rhythm as the cause of selective chromosome elimination in an interspecific Brachiaria hybrid.

This paper reports the occurrence of chromosome elimination during microsporogenesis in an interspecific hybrid between a sexual diploid accession (SEX) of Brachiaria ruziziensis (2n=2x=18) and an apomictic tetraploid accession (APO) of B. brizantha (2 n=4 x=36). Meiosis was very abnormal in the triploid hybrid (2n=3x=27); we observed a distinct asynchrony from metaphase I to the end of meiosis. The APO and the SEX genomes did not show the same meiotic rhythm. When the former, with nine bivalents, was in metaphase I, the nine SEX univalents were not yet aligned; when the latter reached the plate, the APO genome was already in anaphase. In subsequent stages, the APO genome had reached the poles while the SEX was undergoing sister-chromatid segregation. As the SEX genome always remained temporally behind, it gave rise to one extra-nucleus in each pole. In the second division, the behavior was the same but anaphase II did not occur for the SEX genome, and only one extra-nucleus was observed in each cell in telophase II. Chromosome elimination for the SEX genome ranged from partial to total. The importance of these findings with respect to Brachiaria breeding programmes is discussed.

Microsporogenesis in Brachiaria dictyoneura (Fig. & De Not.) Stapf (Poaceae: Paniceae)

icrosporogenesis was analyzed in five accessions of Brachiaria dictyoneura presenting x = 6 as the basic chromosome number. All accessions were tetraploid (2n = 4x = 24) with chromosome pairing in bi-, tri-, and quadrivalents. The recorded meiotic abnormalities were those typical of polyploids, including precocious chromosome migration to the poles, laggard chromosomes, and micronucleus formation. The frequency of these abnormalities, however, was lower than those reported for other polyploid accessions previously analyzed for other Brachiaria species. Cell fusion and absence of cytokinesis were also recorded in some accessions, leading to restitutional nucleus formation in some cells. Genetically unbalanced microspores, binucleate, and 2n microspores were found among normal meiotic products as results from these abnormalities. The limitation in using these accessions as pollen donor in interspecific crosses with sexual species with x = 7 or x = 9 in breeding programs is discussed.

Evidence of allopolyploidy in Brachiaria brizantha (Poaceae: Paniceae) through chromosome arrangement at metaphase plate during microsporogenesis

In the hexaploid (2n = 6x = 54) accession B176 of Brachiaria brizantha, one cytological characteristic differentiated it from the other accessions previously analyzed with the same ploidy level. Nearly 40% of meiocytes displayed the chromosome set arranged at two metaphase plates at the poles of the cell, close to the membrane. In these cells, both metaphase plates were arranged in an angle to form a typical tripolar spindle. Therefore, cells did not show normal chromosome segregation at anaphase I. Only nine univalent chromosomes migrated from each plate to the opposite pole with the remainder staying immobile on the plate. As a result of such spindle orientation and chromosome behavior, trinucleate telophases I were recorded. After telophase, cytokinesis eliminated the small nuclei into a microcyte. The second division proceeded normally, with the presence of microcytes in all phases. The origin of such an abnormality was explained on the hexaploid level of the accession which could have resulted by chromosome doubling of a triploid derived from species that did not display the same behavior for spindle organization. The high percentage of meiotic abnormalities recorded in this accession compromises fertility and renders it inadequate for the breeding program.

Symmetric pollen mitosis I and suppression of pollen mitosis II prevent pollen development in Brachiaria jubata (Gramineae)

Microsporogenesis and pollen development were analyzed in a tetraploid (2n = 4x = 36) accession of the forage grass Brachiaria jubata (BRA 007820) from the Embrapa Beef Cattle Brachiaria collection that showed partial male sterility. Microsporocytes and pollen grains were prepared by squashing and staining with 0.5 percent propionic carmine. The meiotic process was typical of polyploids, with precocious chromosome migration to the poles and laggards in both meiosis I and II, resulting in tetrads with micronuclei in some microspores. After callose dissolution, microspores were released into the anther locule and appeared to be normal. Although each microspore initiated its differentiation into a pollen grain, in 11.1 percent of them nucleus polarization was not observed, i.e., pollen mitosis I was symmetric and the typical hemispherical cell plate was not detected. After a central cytokinesis, two equal-sized cells showing equal chromatin condensation and the same nuclear shape and size were formed. Generative cells and vegetative cells could not be distinguished. These cells did not undergo the second pollen mitosis and after completion of pollen wall synthesis each gave rise to a sterile and uninucleate pollen grain. The frequency of abnormal pollen mitosis varied among flowers and also among inflorescences. All plants were equally affected. The absence of fertile sperm cells in a considerable amount of pollen grains in this accession of B. jubata may compromise its use in breeding and could explain, at least in part, why seed production is low when compared with the amount of flowers per raceme.