Ullrich-Turner syndrome with a small ring X chromosome and presence of mental retardation

Since some patients with Ullrich-Turner syndrome (UTS) have mental retardation, we reviewed our experience to look for a high-risk subgroup. Among 190 UTS and gonadal dysgenesis patients with X chromosome abnormalities, 12 had mental retardation. All of the six (100%) with a small ring X were educable (EMI) or trainable mentally impaired (TMI) with more severe delay than expected in UTS. Among the 184 with other X abnormalities, only 6 had similar delays (2 from postnatal catastrophes), for a frequency of 3.3% mental retardation among those without a small ring X; only 2.2% of these had unexplained mental retardation. Polymerase chain reaction studies showed no Y-derived material in the 2 patients who were evaluated, and in situ hybridization confirmed X origin of the ring in the 6 subjects who were evaluated. We describe the phenotype of the 6 individuals with a small ring X, and an additional 2 patients with a small ring X who were identified outside the survey. The subjects with a small ring X comprised a clinically distinct subgroup which had EMI/TMI and shorter stature than expected in UTS. Seizures and a head circumference <10th centile were observed in half of the patients with a small ring X, and strabismus, epicanthus, and single palmar creases were present in more than half. A “triangular” face in childhood, pigmentary dysplasia, sacral dimple, and heart defects were also common. Neck webbing appeared to be less frequent than in 45, X. We hypothesize that the high risk of mental retardation in this form of the UTS results from lack of lyonization of the ring X due to loss of the X inactivation center. Excluding those with a small ring X, mental retardation is not significantly increased in patients with UTS. © 1992 Wiley-Liss, Inc.     

Ultimate tensile strength of dentin: Evidence for a damage mechanics approach to dentin failure

Dentin structure and properties are known to vary with orientation and location. The present study explored the variation in the ultimate tensile strength (UTS) of dentin with location in the tooth. Hourglass specimens were prepared from dentin located in the center, under cusps, and in the cervical regions of human molar teeth. These were tested in tension at various distances from the pulp. Median tensile strengths ranged from 44.4 MPa in the inner dentin near the pulp, to 97.8 MPa near the dentino-enamel junction (DEJ). This increase in the median UTS with distance from the pulp to the DEJ was statistically significant (P <.001). Of particular importance was the observation that the UTS measurements followed a Weibull probability distribution, with a Weibull modulus of about 4.5. The Weibull behavior of the UTS data strongly suggests that the large variances in fracture strength data result from a distribution of preexisting defects in the dentin. These findings justify a damage-mechanics approach to studies of dentin failure.     

Phalloarteriography in the diagnosis of erectile impotence

An angiographic method has been developed for x-ray visualization of the arteries supplying the cavernous bodies of the penis, namely, the internal iliac, internal pudendal, and penile artery and its branches (dorsal, deep, and bulbocavernous arteries). Under normal conditions the technique makes pulsations in both dorsal penile arteries palpable, and the flow rate of fluid into the cavernous bodies necessary to produce and maintain erection can be determined. The principle of the method involves artificial passive erection or semierection, during which we perform selective or semiselective arteriography of the bed supplied by the internal iliac artery, or retrograde arteriography by puncture of the dorsal artery of the penis. Thirty males complaining of more than 1 year of impotence (including 12 diabetics) were investigated, 29 by our standard technique and 1 by translumbar pelvic arteriography with retrograde arteriography of the dorsal penile artery. All patients showed severe stenosis or obliteration of the vessels supplying the cavernous bodies. There was agreement between absence of pulsation in the dorsal penile arteries and the angiographic findings. Flow rates necessary to produce erection varied from 45 to 160 ml/min, with a mean of 90 ml/min. For controls, angiographic studies were performed in 4 men with clearly psychogenic impotence, all of whom were found to have normal-appearing arteries supplying the cavernous bodies. On the basis of these findings and previously reported histological investigations, we believe that most impotence is the symptomatic and functional result of arterial disease. The arteriographic technique described allows a precise anatomical diagnosis to be made, and can indicate surgical and microsurgical correction.

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Résumé Nous avons mis au point une technique d'angiographic qui visualise la vascularisatioh artérielle des corps caverneux, soit les artères iliaques internes, honteuses internes, péniennes et leurs branches dorsales, profondes et bulbocaverneuses. Dans les conditions normales, la technique permet de palper le pouls dans les artères dorsales de la verge et de mesurer, dans les corps caverneux, le débit nécessaire pour produire et maintenir une érection. Le principe de la méthode repose sur une érection ou semi-érection artificielle passive associée, soit à une artériographie sélective ou semi-sélective du territoire de l'iliaque interne, soit à une artériographie rétrograde par ponction de l'artère dorsale de la verge.Trente hommes (dont 12 diabétiques) ont été étudiés: ils présentaient tous une impuissance depuis plus d'un an. L'investigation a été faite, dans 29 cas avec notre technique standard, dans un cas par aortographie translombaire et arteriographie rétrograde de l'artère dorsale de la verge. Il existait dans tous les cas des sténoses serrées ou des oblitérations de l'arbre artériel allant aux corps caverneux. Les lésions mises en évidence par l'artériographie concordaient avec l'absence de pulsations dans les artères dorsales de la verge. Les débits nécessaires pour produire l'érection ont varié entre 45 et 160 ml/min, avec une moyenne de 90 ml/min. A titre de contrôle, des artériographies ont été faites chez 4 hommes atteints d'impuissance manifestement psychogène: chez tous, l'irrigation artérielle des corps caverneux était normale.Ces résultats, et des études histologiques antérieures, nous amènent à penser que, dans la plupart des cas, l'impuissance est la manifestation symptomatique et fonctionnelle d'une maladie artérielle. La technique d'angiographic que nous avons décrite donne un diagnostic anatomique précis et permet de poser les indications de la chirurgie ou de la microchirurgie correctrice.

     

Fibrous hamartoma of infancy. A study of eight cases with immunohistochemical and electron microscopical findings.

Eight cases of fibrous hamartomas of infancy are presented. Actin positivity and desmin negativity in collagen forming spindle-shaped cells and electron microscopical findings point to the myofibroblastic nature of this entity. "Dark cells" which spread regularly in all but one of our tumors were immunohistochemically determined to be a mixture of B and T cell lymphocytes. Their selective location and possible role are discussed.     

Construction of 0D/2D Schottky Heterojunctions of ZnO and Ti3C2 Nanosheets with the Enriched Transfer of Interfacial Charges for Photocatalytic Hydrogen Evolution

The development of cost-effective co-catalysts of high photocatalytic activity and recyclability is still a challenge in the energy transformation domain. In this study, 0D/2D Schottky heterojunctions, consisting of 0D ZnO and 2D Ti₃C₂, were successfully synthesized by the electrostatic self-assembling of ZnO nanoparticles on Ti₃C₂ nanosheets. In constructing these heterojunctions, Ti₃C₂ nanosheets acted as a co-catalyst for enhancing the transfer of excitons and their separation to support the photocatalytic response of ZnO. The as-prepared ZnO/Ti₃C₂ composites demonstrate an abbreviated charge transit channel, a huge interfacial contact area and the interfacial electrons’ transport potential. The extended optical response and large reactive area of the ZnO/Ti₃C₂ composite promoted the formation of excitons and reactive sites on the photocatalyst’s surface. The ZnO/Ti₃C₂ Schottky heterojunction showed significantly high photocatalytic activity for hydrogen production from a water–ethanol solution under the light illumination in the visible region. The hydrogen evolution overoptimized the ZnO/Ti₃C₂ composition with 30 wt.% of Ti₃C₂, which was eight times higher than the pristine ZnO. These findings can be helpful in developing 0D/2D heterojunction systems for photocatalytic applications by utilizing Ti₃C₂ as a low-cost co-catalyst.