1,720,957 research outputs found
Coagulation-factor deficiencies and abnormal bleeding in Noonan’s syndrome
No full textBackground: Noonan syndrome (NS) is a congenital autosomal disorder,
characterized by dysmorphic facies, congenital heart defects, short stature and
other anomalies including coagulation abnormalities not fully studied so far.
Objective and hypotheses: The aim of this study was to evaluate phenotypic
features, gene mutations and coagulation parameters in a cohort of NS
patients.
Method: We studied 19 NS patients (10 M, 9 F), 12 probands and 7 first degree
relatives, we found in 7/19 a mutation of PTPN11, in 8 of SOS1 and in 1
case of SOS1/RAF1, the remaining 3 cases were mutation-negative.
Results: A positive history for abnormal bleeding was found in 9 patients
(47%), a prolonged PTT in 5 cases (26%), coagulation factors deficiency in 9
patients (47%) and abnormal platelet aggregation in 8 cases (44%); the coagulation
anomalies were found both in the 9 patients with a history of abnormal
bleeding and in 6 cases (60%) without clinical evidence of bleeding disorders.
The coagulation abnormalities were reported both in patients with or without
a mutation and were not correlated with a mutation of a specific gene. Important
differences in haemostatic status were found between probands and
their relatives: the former showed coagulation abnormalities in the majority
of the cases while the latter showed a history of bleeding diathesis, but normal
laboratory hematological findings. The coagulation abnormalities were more
frequent in patients with heart defects; however, a history of bleeding diathesis
was detected in patients without cardiopathy.
Conclusions: A high frequency of coagulation abnormalities was found in
NS. These abnormalities do not seem to be related with the patients’ genotype.
The heart defects should not to be the only cause of the haemostatic disorders.
The bleeding disorders, as well as the other phenotypic NS features, tend to
decrease with age. Our advice is to screen patients with NS for bleeding diathesis
to avoid bleedings and post-operative complications
Cryptic chromosomal deletions detected by array-CGH in four cases affected by central precocious puberty and neurodevelopmental disorders
No full textBackground: Central precocious puberty (CPP) may be associated with CNS abnormalities including neurodevelopmental disorders (ND), epilepsy (E), CNS structural malformations and/or with dysmorphic features. In the literature, some chromosomal aberrations have been reported in patients with this association.
Objective and hypotheses: The aim of this study was to detect cryptic chromosomal anomalies in patients affected by CPP and CNS disorders using the array CGH technique. Methods: We carried on the array-CGH analysis in 4 girls affected by CPP associated with one or more of following CNS anomalies: ND, E and structural abnormalities detected with MRI. The age at the onset of CPP ranged from 4 to 7.3 years.
Results: Case 1. A de novo distal deletion of the chromosome 9 short arm [del(9)(p24.3-p23)] was found, as in the cases affected by 9p- syndrome. To our knowledge, this is the second reported case of precocious puberty associated to 9p distal deletion. Cases 2 and 3. A deletion of the chromosome 8 short arm was found: in the first case the deletion was localized in the region 8p23.2 and in the latter in the region 8p23.3.1. In both these cases the deletion determines the lost of the gene CSMD1, which is known to be particularly expressed in the ovary during the embryogenesis. Moreover, a duplication of CSMD1 has been found in a girl affected by delayed puberty [1]. Case 4. A deletion of chromosome 8p22 was detected, which is cited in the Database of Genomic Variants as a normal variant. However, this deletion may be related with the age at menarche in normal population.
Conclusions: Our observations confirm the usefulness of the array-CGH analysis for detecting cryptic chromosomal aberrations in patients with CPP associated with CNS abnormalities and or dysmorphic features. Further studies are needed to identify genes responsible for this association
Pattern of inheritance and analysis of clinical and cerebral MRI features of familial cases of central precocious puberty
No full textBackground: Many clinical observations show that central precocious puberty
(CPP) may be in some cases familial. However, the scientific support to
this assumption remains sparse up to now.
Objective and hypotheses: The aim of the present study was to define a
pattern of inheritance of familial CPP, and to identify possible clinical differences
between familial (FPP) and sporadic (SPP) forms of CPP.
Methods: We studied 110 patients affected by CPP (104 F, 6 M). The family
tree of each patient was analysed and all information regarding the age of
puberty and of menarche, and the presence of CPP among first and second
degree relatives was collected.
Results: Forty-one cases (37.3%; 40 F, 1M) met the criteria for FPP and the
remaining 69 cases (62.7%; 64 F, 5 M) were SPP. The FPP showed a pattern
of inheritance that was autosomal dominant in 24 (58.5%) cases, autosomal
dominant with incomplete sex-dependent penetrance in 16 (39%) girls and
autosomal recessive in only 1 (2.5%) case. The age at onset and the age at diagnosis
of CPP did not differ between FPP and SPP, the girls with FPP showed
a higher BMI-SDS than girls with SPP (2.77 ± 2.28 SD vs 1.72 ± 1.71SD;
P=0.0402) and a greater bone age acceleration (2.12yrs ± 1.28 SD vs 1.56yrs
± 1.32 SD; P=0.0275). MRI showed CNS anomalies in 14/69 (20%) children
with SPP and in 7/41 (17%) children with FPP.
Conclusions: A familial origin was found in 1/3 of cases with CPP. Girls
with FPP have a higher BMI and bone age maturation than those with SPP.
CNS abnormalities were found either in SPP either in FPP and do not allow to
exclude the need of performing cerebral MRI in FPP. The high prevalence of
FPP suggests a careful inquiry regarding precocious puberty in young siblings
and first-degree cousins of a child diagnosed with CPP
Abnormal growth in Noonan syndrome: correlation between growth parameters and genotype
No full textBackground: Noonan Syndrome (NS) is an autosomal dominant disorder characterized by short stature, dysmorphic features, congenital heart defects and other anomalies. Familial or de novo mutations in PTPN11, RAF1, SOS1, KRAS, and NRAS are detected in 60-75% of cases.
Objective and hypotheses: The aim of this study was to find out a possible correlation between the linear growth, the GH secretion and the genotype in NS patients.
Methods: A cohort of 34 patients affected by NS diagnosed by Van der Burgt criteria was studied: 13 had a PTPN11 mutation, 9 SOS1 (in one case associated with RAF1) and 12 were mutation negative. All of these patients underwent a clinical and auxological evaluation, GH secretion was evaluated in 29 patients.
Results: Short stature was detected in 9/13 (69%) PTPN11+ patients, in 8/12 (67%) mutation negative and only in 2/9 (22%) of SOS1+ patients. The average H-SD was significantly higher in the SOS1+ group compared to PTPN11+ and to mutation negative groups, while no significant difference was found between the latter two groups. The average H-DS of PTPN11+ and of mutation negative groups was significantly lower (p<0,002) than their respective target height (TH) (-1,9±0,88 vs 0,43±1,26 and -2,18±1,4 vs -0,33±1,2, respectively) while it was close to TH in SOS1+ group (-0,63±0,49 vs -0,53±0,37). GH deficiency (GHD) was diagnosed in 4/9 (44%) PTPN11+, 2/8 (25%) SOS1+ and in 3/12 (25%) mutation negative. The final height reached from 5 patients SOS1+ was normal, while it was low in 2 cases PTPN11+.
Conclusions: In this study short stature was more frequently seen in PTPN11+ and mutation negative patients than in those SOS1+. Short stature was rarely observed in SOS1+ patients, and when present, it was secondary to GHD. The SOS1+ patients reached a normal final height, suggesting that this mutation seems to preserve the linear growth in patients with NS
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Serum Anti-Müllerian Hormone (AMH) and Inhibin (IB) levels in girls with isolated premature thelarche and with central precocious puberty
No full textBackground: Inhibin B (IB) and Anti-Müllerian hormone (AMH) are produced
by the granulosa cells in small antral follicles and are sensitive markers
of ovarian follicular activity. Unlike the IB, the AMH production has never
been evaluated in girls with sexual precocity.
Objective and hypotheses: The aim of this study was to determine the IB
and AMH production in girls with premature thelarche (PT) and with central
precocious puberty (CPP) and to investigate whether the production of these
two hormones is influenced by the Gn-RHa therapy.
Method: Heighty-seven girls were enrolled in this study: 25 girls with PT
(1.2-7.8 yrs) and 62 girls with CPP of whom 30 girls (1.4-9.1 yrs) before Gn-
RHa therapy and 32 (5.9-12.4 yrs) during Gn-RHa therapy. The control group
consisted of 26 healthy prepubertal age-matched girls.
Results: Inhibin B levels were higher in girls with PT and with CPP than in
controls; the IB concentrations decreased during GN-RHa therapy. Unlike IB,
AMH levels were significantly (p=0.011) lower in girls with PT than in girls
with CPP, during GnRH-a treatment the AMH concentrations didn’t show
variation respect to pretreatment values. The AMH levels were significantly
(p<0,005) higher in girls showing at ultrasound (US) examination a paucior
multi-follicular ovarian pattern than in those with homogeneous pattern,
no differences were found between IB levels and US ovarian morphology. A
positive correlation was found between IB and FSH levels and between AMH
and estradiol levels.
Conclusions: AMH showed a different trend from IB in patients with PT and
CPP. AMH levels better correlate than IB with the ovarian morphology and
therefore seem to be more specific than IB in showing the presence of follicular
activity. Unlike IB, AMH production didn’t decrease during Gn-RHa
therapy, this suggests that other factors other than the gonadotropins may
regulate the ovarian follicular activity
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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