Skeletal changes associated with vascular malformations

Five hundred and eighty birthmarks were reviewed; 356 were hemangiomas and 224 were malformations. Bony alterations occurred in association with only 1 percent of hemangiomas, in contrast with 34 percent of patients with vascular malformations. These alterations in bone development were classified according to size, shape, and density changes. Hypertrophy and distortion were typical of lymphatic malformations. Hypoplasia and demineralization were characteristic findings in the extremity venous malformations. Destructive and intraosseous changes were more commonly noted in the arterial or high-flow lesions. Possible mechanisms of altered skeletal growth include mechanical, physiological, and developmental processes.     

Study of general toxic properties and side effects of polymethylsiloxane and gentamicin immobilized on it

A long-acting dosage form for local use of gentamicin immobilized on polymethylsiloxane, a silicon organic adsorbent was developed. It combined the antimicrobial spectrum of gentamicin and the local sorption-detoxication action of the matrix. In acute and chronic experiments on 5 species of laboratory animals it was shown that polymethylsiloxane had no general toxic action on the animals, no damaging action on their internal organs, did not affect their functions and the state of the biological fluids, had no pyrogenic or allergenic effect. During gentamicin immobilization on polymethylsiloxane there was observed no increase in the antibiotic toxicity as compared to the nonimmobilized dosage form of the antibiotic. Further study of the immobilized dosage form of gentamicin is advisable.     

Citric acid production by a novel autochthonous Candida zeylanoides isolate: optimization of process parameters

Biotechnology Letters - In this study, citric acid (CA) production by autochthonous Candida zeylanoides 7.12 was investigated and optimized. Response surface methodology (RSM) was used for...     

Facial skeletal changes following hypertelorbitism correction

This is a retrospective study of skeletal changes in 19 patients with corrected hypertelorism. A favorable outcome, defined as relapse less than 5 mm, occurred in patients with an average interorbital distance of 32 mm, whereas patients with an average interorbital distance of 40 mm tended to relapse over 5 mm. Neither age, interorbital configuration, nor diagnosis affected the stability of orbital translocation. At last evaluation (mean 6.7 years postoperatively), the mean interorbital distance was 22.4 mm in the favorable outcome group and 28.3 mm in the unfavorable category. This study suggested that the standard hypertelorism operation may interfere with anterior facial growth. Unless psychosocial factors predominate in a child with mild deformity, repair should be postponed until late adolescence. In a young child with gross telorbitism, nasoethmoidal resection and transmaxillary osteotomies or facial bipartition is justified. Another long-term skeletal problem was resorption of the reconstructed nasal complex. Technical and biological explanations for this are given. The correction of hypertelorism is surgery of the nose and of the midface.     

Tissue engineered hybrid tooth-bone constructs

Proper rehabilitation of craniofacial defects is challenging because of the complexity of the anatomy and the component tissue types. The ability to simultaneously coordinate the regeneration of multiple tissues would make reconstruction more efficient and might reduce morbidity and improve outcomes. The craniofacial complex is unique because of the presence of teeth, in addition to skin, bone, cartilage, muscle, vascular, and neural tissues since teeth naturally grow in coordination with the craniofacial skeleton, our group developed an autologous, tooth-bone hybrid model to facilitate repair of mandibular defects in the Yucatan minipig. The hybrid tooth-bone construct was prepared by combining tooth bud cell-seeded scaffolds with autologous iliac crest bone marrow derived stem cell-seeded scaffolds, which were transplanted back into surgically created mandibular defects in the same minipig. The constructs were harvested after 12 and 20 weeks of growth. The resulting bone/tooth constructs were evaluated by X-ray, ultra high-resolution volume computed tomography (VCT), histological, immunohistochemical analyses, and transmission electron microscopy (TEM). The observed formation of small tooth-like structures consisting of organized dentin, enamel, pulp, cementum, periodontal ligament, and surrounded by regenerated alveolar bone, suggests the feasibility for regeneration of teeth and associated alveolar bone, in a single procedure. This model provides an accessible method for future clinical applications in humans.     

Midface position after LeFort III advancement

Nineteen of 30 patients who had midface advancement procedures between 1972 and 1980 had sufficient cephalometric data to be included in this retrospective study. The position of the midface in relation to the cranium and mandible was evaluated immediately postoperatively and for a period of 2 to 11 years (mean 5.8 years). At 1 year, midface position after LeFort III advancement was stable in 12 of 19 patients. Of these 12 patients, 8 showed some evidence of downward and/or forward movement of the midface. The remaining 7 patients showed a minor degree of midface relapse in the first year of follow-up. In 15 of 19 patients, at 2 years or more postoperatively, the final position of the midface was either at, anterior to, or inferior to its immediate postoperative location. Correction of exorbitism remained stable in all but one patient, who required a second advancement of the orbital segment. Three patients required subsequent LeFort I osteotomy to correct class III occlusion. Prognathism was determined to be secondary to mandibular growth, not midface relapse.     

Cherubism: best clinical practice

Cherubism is a skeletal dysplasia characterized by bilateral and symmetric fibro-osseous lesions limited to the mandible and maxilla. In most patients, cherubism is due to dominant mutations in the SH3BP2 gene on chromosome 4p16.3. Affected children appear normal at birth. Swelling of the jaws usually appears between 2 and 7 years of age, after which, lesions proliferate and increase in size until puberty. The lesions subsequently begin to regress, fill with bone and remodel until age 30, when they are frequently not detectable.Fibro-osseous lesions, including those in cherubism have been classified as quiescent, non-aggressive and aggressive on the basis of clinical behavior and radiographic findings. Quiescent cherubic lesions are usually seen in older patients and do not demonstrate progressive growth. Non-aggressive lesions are most frequently present in teenagers. Lesions in the aggressive form of cherubism occur in young children and are large, rapidly growing and may cause tooth displacement, root resorption, thinning and perforation of cortical bone.Because cherubism is usually self-limiting, operative treatment may not be necessary. Longitudinal observation and follow-up is the initial management in most cases. Surgical intervention with curettage, contouring or resection may be indicated for functional or aesthetic reasons. Surgical procedures are usually performed when the disease becomes quiescent. Aggressive lesions that cause severe functional problems such as airway obstruction justify early surgical intervention.     

The dystrophin / utrophin homologues in Drosophila and in sea urchin

The gene which is defective in Duchenne muscular dystrophy (DMD) is the largest known gene containing at least 79 introns, some of which are extremely large. The product of the gene in muscle, dystrophin, is a 427 kDa protein. The same gene encodes at least two additional non-muscle full length dystrophin isoforms transcribed from different promoters located in the 5'-end region of the gene, and four smaller proteins transcribed from internal promoters located further downstream, and lack important domains of dystrophin. Several other genes, encoding evolutionarily related proteins, have been identified. To study the evolution of the DMD gene and the significance of its various products, we have searched for genes encoding dystrophin-like proteins in sea urchin and in Drosophila. We previously reported on the characterization of a sea urchin gene encoding a protein which is an evolutionary homologue of Dp116, one of the small products of the mammalian DMD gene, and on the partial sequencing of a large product of the same gene. Here we describe the full-length product which shows strong structural similarity and sequence identity to human dystrophin and utrophin. We also describe a Drosophila gene closely related to the human dystrophin gene. Like the human gene, the Drosophila gene encodes at least three isoforms of full length dystrophin-like proteins (dmDLP1, dmDLP2 and dmDLP3,), regulated by different promoters located at the 5' end of the gene, and a smaller product regulated by an internal promoter (dmDp186). As in mammals, dmDp186 and the dmDLPs share the same C-terminal and cysteine-rich domains which are very similar to the corresponding domains in human dystrophin and utrophin. In addition, dmDp186 contains four of the spectrin-like repeats of the dmDLPs and a unique N-terminal region of 512 amino acids encoded by a single exon. The full length products and the small product have distinct patterns of expression. Thus, the complex structure of the dystrophin gene, encoding several large dystrophin-like isoforms and smaller truncated products with different patterns of expression, existed before the divergence between the protostomes and deuterostomes. The conservation of this gene structure in such distantly related organisms, points to important distinct functions of the multiple products.     

Progression of facial asymmetry in hemifacial microsomia

Hemifacial microsomia is a common craniofacial anomaly, variably affecting structures derived from the first and second pharyngeal arches. Correction of the skeletal deformity in children has been advocated to improve growth potential and reduce secondary deformity. However, contrary reports have suggested that facial asymmetry in hemifacial microsomia does not increase with growth; therefore, skeletal correction can be postponed, even until adolescence. The purpose of this study was to test the hypothesis that facial asymmetry in hemifacial microsomia is progressive. This is a retrospective evaluation of 67 patients with untreated hemifacial microsomia. The patients were categorized as: group I (mandible type I, IIa), n = 38, and group II (mandible type IIb, III), n = 29. Pretreatment posterior-anterior cephalometric radiographs were used to analyze asymmetry by measuring the angle between the true horizontal and the following planes: piriform rim, maxillary occlusal plane, and intergonial angle. Angular measurements were averaged for patients in the deciduous (<6 years), mixed (> or =6<13 years), and permanent dentition (> or =13 years). In group I, angle piriform rim, maxillary occlusal plane, and intergonial angle increased from 7.0, 4.3, and 4.4 to 8.4, 6.6, and 6.1 degrees, respectively [mean age, 4.1 (deciduous) to 8.6 (mixed) to 21.0 (permanent) years]. In group II, angle piriform rim, maxillary occlusal plane, and intergonial angle increased from 9.5, 6.2, and 5.3 to 11.7, 7.6, and 8.0 degrees, respectively [mean age, 3.4 (deciduous) to 8.0 (mixed) years]. These data demonstrate that hemifacial microsomia is progressive and underscores the importance of early surgical correction of mandibular asymmetry in this disorder.