Failure of testicular development associated with a rearrangement of 9p24.1 proximal to the SNF2 gene

In 46,XY individuals, testes are determined by the activity of the SRY gene (sex-determining region Y), located on the short arm of the Ychromosome. The other genetic components of the cascade that leads to testis formation are unknown and may be located on the Xchromosome or on the autosomes. Evidence for the existence of several loci associated with failure of male sexual development is indicated by reports of 46,XY gonadal dysgenesis associated with structural abnormalities of the Xchromosome or of autosomes (chromosomes9, 10, 11 and 17). In this report, we describe the investigation of a child presenting with multiple congenital abnormalities, mental retardation and partial testicular failure. The patient had a homogeneous de novo 46,XY,inv dup(9)(pter→p24.1::p21.1 →p23.3::p24.1→qter) chromosome complement. No deletion was found by either cytogenetic or molecular analysis. The SRY gene and DSS region showed no abnormalities. Southern blotting dosage analysis with 9p probes and fluorescent in situ hybridisation data indicated that the distal breakpoint of the duplicated fragment was located at 9p24.1, proximal to the SNF2 gene. We therefore suggest that a gene involved in normal testicular development and/or maintenance is present at this position on chromosome 9. Received: 20 January 1997 / Accepted: 5 November 1997     

Transferrin, somatomedins and growth

Plasma transferrin is significantly positively correlated to the growth velocity in normal children and children with various growth disorders. In hypopituitary dwarfs, both plasma transferrin and somatomedin are significantly lower than in controls. Acute variations of the plasma transferrin levels could be involved in the regulation of the GH secretion by a feedback mechanism. Yet, transferrin is neither a somatomedin or a somatomedin-binding protein, and the mechanisms relating growth to transferrin remain unknown.     

Biodeterioration of Mayan buildings at uxmal and tulum,Mexico

Uxmal and Tulum are two important Mayan sites in the Yucatan peninsula. The buildings are mainly composed of limestone and grey/black discoloration is seen on exposed walls and copious greenish biofilms on inner walls. The principal microorganisms detected on interior walls at both Uxmal and Tulum were cyanobacteria; heterotrophic bacteria and filamentous fungi were also present. A dark‐pigmented mitosporic fungus and Bacillus cereus, both isolated from Uxmal, were shown to be acidogenic in laboratory cultures. Cyanobacteria belonging to rock‐degrading genera Synechocystis and Gloeocapsa were identified at both sites. Surface analysis previously showed that calcium ions were present in the biofilms on buildings at Uxmal and Tulum, suggesting the deposition of biosolubilized stone. Apart from their potential to degrade the substrate, the coccoid cyanobacteria supply organic nutrients for bacteria and fungi, which can produce organic acids, further increasing stone degradation.     

MEPE-Derived ASARM Peptide Inhibits Odontogenic Differentiation of Dental Pulp Stem Cells and Impairs Mineralization in Tooth Models of X-Linked Hypophosphatemia

Mutations in PHEX (phosphate-regulating gene with homologies to endopeptidases on the X-chromosome) cause X-linked familial hypophosphatemic rickets (XLH), a disorder having severe bone and tooth dentin mineralization defects. The absence of functional PHEX leads to abnormal accumulation of ASARM (acidic serine- and aspartate-rich motif) peptide − a substrate for PHEX and a strong inhibitor of mineralization − derived from MEPE (matrix extracellular phosphoglycoprotein) and other matrix proteins. MEPE-derived ASARM peptide accumulates in tooth dentin of XLH patients where it may impair dentinogenesis. Here, we investigated the effects of ASARM peptides in vitro and in vivo on odontoblast differentiation and matrix mineralization. Dental pulp stem cells from human exfoliated deciduous teeth (SHEDs) were seeded into a 3D collagen scaffold, and induced towards odontogenic differentiation. Cultures were treated with synthetic ASARM peptides (phosphorylated and nonphosphorylated) derived from the human MEPE sequence. Phosphorylated ASARM peptide inhibited SHED differentiation in vitro, with no mineralized nodule formation, decreased odontoblast marker expression, and upregulated MEPE expression. Phosphorylated ASARM peptide implanted in a rat molar pulp injury model impaired reparative dentin formation and mineralization, with increased MEPE immunohistochemical staining. In conclusion, using complementary models to study tooth dentin defects observed in XLH, we demonstrate that the MEPE-derived ASARM peptide inhibits both odontogenic differentiation and matrix mineralization, while increasing MEPE expression. These results contribute to a partial mechanistic explanation of XLH pathogenesis: direct inhibition of mineralization by ASARM peptide leads to the mineralization defects in XLH teeth. This process appears to be positively reinforced by the increased MEPE expression induced by ASARM. The MEPE-ASARM system can therefore be considered as a potential therapeutic target.     

Gonadotropin releasing hormone agonist treatment for central precocious puberty

Several methodological problems complicate the evaluation of final statural height (FH) benefit after treatment with gonadotropin releasing hormone (GnRH) agonists for central precocious puberty (CPP). Since no controlled study has been performed, we have to rely on indirect methods, comparison with predicted height or with historical controls. FH of 58 girls, uniformly treated with triptorelin slow release formulation (triptorelin-SR, Decapeptyl((R))) for CPP were compared with predicted height before treatment and with FH of an historical group of patients not treated with GnRH agonist. The comparison with predicted height revealed an improvement of 4.8 +/- 5.8 cm; comparison with the historical control group showed a mean improvement of 8.3 cm. The post-treatment growth spurt (DeltaFH - height at the end of treatment) was a strong predictor of FH in multivariate analysis. The data suggest that continuing treatment beyond the age of 11 in girls does not improve and could actually decrease FH.     

Multimodal pressure-flow method to assess dynamics of cerebral autoregulation in stroke and hypertension

Background

This study evaluated the effects of stroke on regulation of cerebral blood flow in response to fluctuations in systemic blood pressure (BP). The autoregulatory dynamics are difficult to assess because of the nonstationarity and nonlinearity of the component signals.

Methods

We studied 15 normotensive, 20 hypertensive and 15 minor stroke subjects (48.0 ± 1.3 years). BP and blood flow velocities (BFV) from middle cerebral arteries (MCA) were measured during the Valsalva maneuver (VM) using transcranial Doppler ultrasound.

Results

A new technique, multimodal pressure-flow analysis (MMPF), was implemented to analyze these short, nonstationary signals. MMPF analysis decomposes complex BP and BFV signals into multiple empirical modes, representing their instantaneous frequency-amplitude modulation. The empirical mode corresponding to the VM BP profile was used to construct the continuous phase diagram and to identify the minimum and maximum values from the residual BP (BP_R) and BFV (BFV_R) signals. The BP-BFV phase shift was calculated as the difference between the phase corresponding to the BP_R and BFV_R minimum (maximum) values. BP-BFV phase shifts were significantly different between groups. In the normotensive group, the BFV_R minimum and maximum preceded the BP_R minimum and maximum, respectively, leading to large positive values of BP-BFV shifts.

Conclusion

In the stroke and hypertensive groups, the resulting BP-BFV phase shift was significantly smaller compared to the normotensive group. A standard autoregulation index did not differentiate the groups. The MMPF method enables evaluation of autoregulatory dynamics based on instantaneous BP-BFV phase analysis. Regulation of BP-BFV dynamics is altered with hypertension and after stroke, rendering blood flow dependent on blood pressure.

     

IMAGe association: additional clinical features and evidence for recessive autosomal inheritance

Congenital adrenal hypoplasia (CAH) normally occurs in the neonatal period, with patients presenting with more or less severe salt-wasting syndrome. X-linked CAH has been associated with mutations in the DAX-1 gene, and boys have also been shown to have hypogonadotrophic hypogonadism. Recently, in three unrelated boys, CAH was associated with intrauterine growth retardation (IUGR), metaphyseal dysplasia and genital abnormalities, defining a new association called IMAGe. We now report four additional patients with this association, including the first living female. The four patients belong to two unrelated families (one brother and one sister from each family). These patients have the main clinical characteristics of IMAGe association: IUGR, facial dysmorphy (frontal bossing, broad nasal bridge, low-set ears), short limbs due to metaphyseal dysplasia, and adrenal insufficiency. As these patients are older than the initial three patients, we can also describe additional features: short adult height, normal puberty in boys as well as in the living girl. The boys have hypospadias associated with micropenis. The living girl came to clinical attention at the age of 5 years as a result of a familial survey, and careful questioning revealed that she had been suffering from mild adrenal insufficiency since early childhood. At least one boy has congenital hypotonia due to muscular dystrophy. In conclusion, these four new cases display familial transmission, strongly suggesting Mendelian autosomal recessive inheritance. Adrenal insufficiency may be mild. Hypotonia, described in all the patients, might be related to paucisymptomatic muscular dystrophy, as this condition is clearly heterogeneous varying with regard to severity, associated manifestations and outcome. If this symptom is part of the syndrome, which we cannot assume, it could help to localize the candidate gene.     

Evaluation of adolescent statural growth in health and disease: reliability of assessment from height measurement series and development of an automated algorithm

OBJECTIVES: The precise evaluation of adolescent growth spurt is necessary for numerous clinical research studies of growth disorders and treatments. The objectives of our study were: (1) to evaluate the reliability of clinicians' 'manual' evaluation of the adolescent growth spurt from a collected series of height data, and (2) to construct an automated algorithm to determine the duration of the two phases of growth in health and disease (spurt and final slow growth) independent of clinical pubertal stages. METHODS: One hundred and seventy-four growth curves of normally growing, GH-deficient and Turner's syndrome subjects were presented twice to 2 experienced clinicians. Disagreement between evaluations and clinicians were settled to obtain a 'consensual gold standard' evaluation versus which the algorithm was assessed. Kappa statistics and Bland-Altman analyses were used to evaluate the reliability and agreement of the evaluations. RESULTS: The reliability of 'manual' evaluation of adolescent growth spurt from collected series of height data appeared to be poor. Conversely, the developed algorithm is perfectly reliable and satisfactorily valid. Discrepancies with the clinical consensual gold standard were always fewer than the discrepancies between the expert clinicians, and were observed in similarly difficult curves. CONCLUSION: The developed algorithm may be useful for diverse clinical and biological research applications in children with growth disorders. This study also confirms the value of a comprehensive investigation of growth during adolescence independent of clinical staging.     

Efflux pumps expression and its association with porin down-regulation and β-lactamase production among <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> causing bloodstream infections in Brazil

Background  

Multi-drug efflux pumps have been increasingly recognized as a major component of resistance in P. aeruginosa. We have investigated the expression level of efflux systems among clinical isolates of P. aeruginosa, regardless of their antimicrobial susceptibility profile.