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At least 163 records · Page 9Linked to original sources
PubMed1995

A review of 60 consecutive fibula free flap mandible reconstructions.

Sixty consecutive fibula free flap mandible reconstructions were performed for oncologic defects. Patient age averaged 46.7 years. Eighty-one percent were primary reconstructions. Sixty-two percent were lateral defects; 22 percent were anterior; and the remainder had combined defects. The bone gap averaged 9.4 cm. A skin island was included with the fibula in 85 percent of patients but was actually needed in only 62 percent. Miniplate fixation was used in 96 percent. Templates derived from radiographic studies were used as an aid in shaping the fibula. Average anesthesia time was 14.54 hours; the transfusion requirement, 3 units; and hospitalization, 22 days. Fifty-nine flaps were successfully transferred. Ninety percent of skin islands raised were completely viable. Average postoperative interincisal opening was 35.2 mm. Osseointegrated implants were placed in 56 percent of suitable candidates, and all implants integrated into bone. Aesthetic results were usually good when the soft tissue defect was limited, but poor when it was extensive. Donor site morbidity was usually mild and transient. The most significant problem was delayed healing in patients closed with a skin graft. Postoperatively, all patients ambulated normally, and none used assist devices. Reoperation for donor site problems was rare. The fibula has many assets that together make it an ideal choice for the reconstruction of most mandible defects. The skin island is usually reliable if it is designed and raised properly. Donor site morbidity is largely inconsequential. The primary contraindication to the use of the fibula for mandible reconstruction is severe peripheral vascular disease.

Adolescent↗
PubMed1984

Reconstruction of a large lateral abdominal wall defect with an ilio-lumbar bi-pedicled flap.

An ilio-lumbar bi-pedicled flap was used for the reconstruction of a large lateral abdominal wall defect with a fascia lata graft to provide the musculo-fascial layer. This flap is simple and safe because it includes both the superficial circumflex iliac vessels and the perforating cutaneous branches of the lumbar vessels. We regard it as the method of choice in the repair of major defects of the lateral abdominal wall.

Abdominal Muscles↗
PubMed1996

Cyclopia and defective axial patterning in mice lacking Sonic hedgehog gene function.

Targeted gene disruption in the mouse shows that the Sonic hedgehog (Shh) gene plays a critical role in patterning of vertebrate embryonic tissues, including the brain and spinal cord, the axial skeleton and the limbs. Early defects are observed in the establishment or maintenance of midline structures, such as the notochord and the floorplate, and later defects include absence of distal limb structures, cyclopia, absence of ventral cell types within the neural tube, and absence of the spinal column and most of the ribs. Defects in all tissues extend beyond the normal sites of Shh transcription, confirming the proposed role of Shh proteins as an extracellular signal required for the tissue-organizing properties of several vertebrate patterning centres.

Animals↗
PubMed2001

Significance of chromosome 22q11 analysis after detection of an increased first-trimester nuchal translucency.

OBJECTIVE: To determine the value of performing routine fluorescent in situ hybridization (FISH) for microdeletions of chromosome 22q11 when karyotyping fetuses with increased nuchal translucency. DESIGN: This was a prospective observational study carried out over an 18-month period. Fetal karyotyping by chorionic villus sampling was offered to 5429 women attending for a routine booking scan in the first trimester when their nuchal translucency adjusted risk for Down syndrome was > or = 1 in 300. Cytogenetic samples were routinely tested for the 22q11 microdeletion when the nuchal translucency was > or = 3 mm. RESULTS: The prevalence of increased nuchal translucency > or = 2.5 mm was 180 (3.3%) and > or = 3.5 mm was 42 (0.8%). None of 75 fetuses with an increased nuchal translucency and normal karyotype demonstrated a 22q11 microdeletion on FISH analysis. In the same cohort, 3 of 20 (15%) cases of major congenital heart defects in which nuchal translucency was measured, had a nuchal translucency measurement > or = 2.5 mm. CONCLUSIONS: Routine FISH analysis for chromosome 22q11 microdeletions at the time of chorionic villus sampling for increased first-trimester nuchal translucency is of limited value. As a significant proportion of fetuses with increased nuchal translucency will be found to have congenital heart defects later in the pregnancy, FISH analysis for chromosome 22q11 microdeletions can be targeted to fetuses with specific congenital heart defects. Tissue from the chorionic villus sampling should therefore be stored for subsequent analysis, until after detailed echocardiography is performed.

Adolescent↗
PubMed1984

Retained cartilage in the distal radial physis of foals.

Examination of growth plate defects in the distal radial physis of 13 foals three to 70 days of age revealed lesions in the lateral and medial aspects of the distal radial physis; the lateral defects were more numerous and obvious. Lesions consisted of widening of the zone of hypertrophying cells of the metaphyseal growth plate (retained cartilage), retained cartilage with discontinuity of cartilage and primary spongiosa, and microfracture of the primary spongiosa. In some foals, the cartilage retention was thought to be due to primary spongiosa microfracture, although fracture subsequent to cartilage abnormality was not excluded.

Animals↗
PubMed2004

Methyl methacrylate cranioplasty.

We conducted a prospective study in order to audit our experience of repairing cranial defects using Methyl methacrylate. This included a total of 49 patients undergoing cranioplasty using methyl methacrylate, of which 45 were males and 4 females. The age of patients at the time of surgery ranged from 16 to 40 years old, with an average of 24 years. Malays were the majority (67%), followed by Chinese (23%) and Indian (10%). Cranial defects were mainly caused by motor vehicle accident (94%), while gunshot wounds, industrial accidents and tumours, each contribute 2%. Bone flaps were commonly removed during previous surgery related to traumatic subdural haemorrhage (33%), contusion (21%) and intracerebral haemorrhage (14%). The size of cranial defects ranged from 28 cm2 to 440 cm2, with an average of 201 cm2. Most had right sided (55%) and lateral defects [temporoparietal (52%) followed by temporal (16%), frontal (16%), frontotemporal (14%) and occipital (2%)]. Duration of surgery ranged from 70 to 275 minutes, with an average of 135 minutes. Nine of 12 patients (75%) with neurological disability had some improvement while 85% of symptomatic patients had symptoms improvement after cranioplasty. The infection rate in this series was 4%.

Adolescent↗
PubMed1980

Lateral meningocele and defect of abdominal wall.

A case of lateral meningocele associated with deficiency of the thoraco-abdominal wall is reported. It is suggested that both of these defects are due to interference with the development of the paraxial mesoderm by a single injury.

Abdominal Muscles↗
PubMed1999

Pitx2 regulates lung asymmetry, cardiac positioning and pituitary and tooth morphogenesis.

Pitx1 and Pitx2 are highly homologous, bicoid-related transcription factors. Pitx2 was initially identified as the gene responsible for the human Rieger syndrome, an autosomal dominant condition that causes developmental abnormalities. Pitx2 is asymmetrically expressed in the left lateral-plate mesoderm, and mutant mice with laterality defects show altered patterns of Pitx2 expression that correlate with changes in the visceral symmetry (situs). Ectopic expression of Pitx2 in the right lateral-plate mesoderm alters looping of the heart and gut and reverses body rotation in chick and Xenopus embryos. Here we describe the phenotype of Pitx2 gene-deleted mice, characterized by defective body-wall closure, right pulmonary isomerism, altered cardiac position, arrest in turning and, subsequently, a block in the determination and proliferation events of anterior pituitary gland and tooth organogenesis. Thus, Pitx2 is a transcription factor that encodes 'leftness' of the lung.

Abnormalities, Multiple↗
PubMed2000

Body stalk defects, body wall defects, amniotic bands with and without body wall defects, and gastroschisis: comparative epidemiology.

The presence of body wall defects with "evisceration" of thoracic and/or abdominal organs associated with other congenital anomalies, with or without limb deficiencies, is considered to be the body wall complex (BWC). The BWC is different from gastroschisis, which is usually a small body wall defect lateral to the umbilical cord that is not covered by any membrane and, in most of the cases, is an isolated defect. For the present analysis we separated the BWC group into three subgroups. One group was that of body stalk anomalies characterized by severe defects of the abdominal wall with absence of, or very small, umbilical cord, or this is continuing with the placenta. The second group was made up of those infants with body wall defects without amniotic bands, and the third group was of those children with body wall defects produced by amniotic bands. We considered two additional groups in the analysis, one was of infants with gastroschisis and the other those infants with amniotic bands without body wall affectation. We also included the control group (nonmalformed infants) for comparisons. From the results of our epidemiological study, we can conclude that amniotic bands with body wall affectation and amniotic bands without body wall defects are two different entities. The results also suggest that the characteristics of infants with amniotic bands with body wall defects are more similar to the group of infants with body stalk anomalies. This may indicate that the former group is produced during the very early gestation.

Abdominal Muscles↗
PubMed2000

Cardiovascular malformations and other cardiovascular abnormalities in neurofibromatosis 1.

Although it is well recognized that a peripheral vasculopathy may occur in patients with neurofibromatosis 1 (NF1), it is unclear whether cardiovascular abnormalities are more common. We reviewed the frequency of cardiovascular abnormalities, in particular, cardiovascular malformations (CVMs), among 2322 patients with definite NF1 in the National Neurofibromatosis Foundation International Database from 1991-98. Cardiovascular malformations were reported in 54/2322 (2.3%) of the NF1 patients, only 4 of whom had Watson syndrome or NF1-Noonan syndrome. There was a predominance of Class II "flow" defects [Clark, 1995: Moss and Adams' Heart Disease in Infants, Children, and Adolescents Including the Fetus and Young Adult. p 60-70] (43/54, 80%) among the NF1 patients with CVMs. Pulmonic stenosis, that was present in 25 NF1 patients, and aortic coarctation, that occurred in 5, constitute much larger proportions of all CVMs than expected. Of interest was the paucity of Class I conotruncal defects (2 patients with tetralogy of Fallot), and the absence of atrioventricular canal, anomalous pulmonary venous return, complex single ventricle and laterality defects. Besides the 54 patients with CVMs, there were 27 patients with other cardiac abnormalities (16 with murmur, 5 with mitral valve prolapse, 1 with intracardiac tumor, and 5 with electrocardiogram abnormalities). No patient in this study had hypertrophic cardiomyopathy. There were 16 patients who had a peripheral vascular abnormality without an intracardiac CVM, plus an additional 4 patients among those with a CVM who also had a peripheral vascular abnormality.

Aortic Coarctation↗
PubMed2003

Analysis of the embryonic phenotype of Bent tail, a mouse model for X-linked neural tube defects.

Neural tube defects, mostly believed to result from closure defects of the neural tube during embryonic development, are frequently observed congenital malformations in humans. Since the etiology of these defects is not well understood yet, many animal models for neural tube defects, either arising from spontaneous mutations or generated by gene targeting, are being studied. The Bent tail mouse is a model for X-linked neural tube defects. This mutant has a characteristic short and kinked tail. Exencephaly occurs in Bent tail embryos with a frequency of 11-16%. Laterality defects also belong to the phenotypic spectrum. In this study, we analyzed the embryonic phenotype in further detail using scanning electron microscopy during the stages of neurulation. We observed a number of defects in both wild type and Bent tail embryos, including a kinked neural tube, tight amnion, delay in axial rotation and even malrotation. The severity or frequency of most defects, the delay in axial rotation excluded, was significantly higher in Bent tail embryos compared to wild type embryos. Other abnormalities were seen in Bent tail embryos only. These defects were related to anterior and posterior neural tube closure and resulted in exencephaly and a closure delay of the posterior neuropore, respectively. The exencephalic phenotype was further analyzed by light microscopy in ED14 embryos, showing disorganization and overgrowth in the mesencephalon and rhombencephalon. In conclusion, the anterior and posterior neural tube closure defects in the Bent tail are strictly linked to the genetic defect in this mouse. Other phenotypic features described in this study also occur in the wild type genetic background of the Bent tail strain. Apparently, the genetic background contains elements conducive to these developmental abnormalities.

Animals↗
PubMed2000

Online Mendelian Inheritance in Man (OMIM) as a knowledgebase for human developmental disorders.

In this review, we summarize the current genetic information on human developmental disorders found in Online Mendelian Inheritance in Man (OMIM). The OMIM catalogues human phenotypes and genotypes and relevant mouse models. Among the more than 11005 genetic disorders and loci, we found at least 1231 human conditions with known gene mutationsffWe searched for human developmental disorders that present with structural defects during the perinatal period, and identified 162 such entries. We classified these entries by phenotypic features (e.g., skeletal dysplasias, axis and laterality defects, or eye disorders) and by the type of gene mutated (e.g., genes coding for transcription factors, structural proteins, enzymes, or receptors). Thirty-eight entries have allelic variants with gene mutations causing different functional consequences, thereby altering their interactions with modifying genes. Thirty-two entries show genetic heterogeneity due to either functional redundancy of more than one gene or genes that interact in common developmental pathways. Although many different types of genes are mutated in developmental disorders, we found that the disease genes are transcription factors in 49 entries. Mouse models are available for many of the human conditions, with the majority of these mutants being secondary to null mutations. These data allow us to begin to elucidate the complex developmental pathways involved in the molecular pathogenesis of human malformations.

Data Collection↗
PubMed2003

Phenotype of the neural tube defect mouse model bent tail is not sensitive to maternal folinic acid, myo-inositol, or zinc supplementation.

BACKGROUND: Bent tail is a mouse model for X-linked neural tube defects (NTDs) that is characterized by the presence of exencephaly, a delayed posterior neuropore closure, and a tail phenotype. In addition, Bent tail shows laterality defects and increased prenatal mortality. The congenital malformations of this mouse are caused by a submicroscopic deletion that completely encompasses the gene coding for the zinc finger transcription factor Zic3. In this study we investigated the sensitivity of the phenotype of Bent tail to the nutrients folinic acid, myo-inositol, and zinc. These nutrients are thought to be involved in the etiology of NTDs, in combination with a genetic predisposition. METHODS: The most penetrant phenotype of the Bent tail mouse, the tail malformation, was used as a marker for the nutrient sensitivity of the neural phenotype. The size of the litters and the survival of the offspring, subdivided according to genotype, were analyzed as markers for the nutrient sensitivity of other phenotypic features of Bent tail. RESULTS: In confirmation of earlier studies, we observed the prenatal loss of a number of homozygous females and hemizygous males, as well as the effect of genotype on the tail phenotype of Bent tail. However, periconceptional supplementation of the maternal diet with folinic acid, myo-inositol, or zinc produced no significant effects on either the tail phenotype of the offspring or the size and genotypic composition of the litters. CONCLUSIONS: Bent tail appears to be a folinic acid-, myo-inositol-, and zinc-insensitive mouse model for NTDs.

Animals↗
PubMed1997

Molecular genetics of congenital heart disease.

This review of advances made toward understanding the molecular basis of congenital heart disease covers studies on subjects ranging from atrioventricular septal defects to zebrafish models. Genetically abnormal mice with atrioventricular septal defects have abnormal endocardial cushion development with the delayed appearance of mesenchymal cells and certain critical adhesion proteins. The prevalence of 22q11 deletions among patients with the conotruncal defects was estimated at 8% to 17%. Deletions were rare among patients lacking typical DiGeorge syndrome (DGS) or velocardiofacial (VCF) dysmorphic features, and more common in tetralogy of Fallot with pulmonary atresia than tetralogy of Fallot alone. Studies with patients with unusual 22q11 defects revealed that regional effects on several genes seem to underlie these complex phenotypes. A second DGS/VCF region on chromosome 10p13 was defined molecularly. Laterality defects (heterotaxy) have been associated with connexin43 mutations, and mice lacking connexin43 developed pulmonary atresia with intact ventricular septum. Three other groups failed to find connexin43 mutations in heterotaxy patients, suggesting genetic heterogeneity. Studies of cardiac looping with lower vertebrates revealed the critical role of the notochord. Ellis-van Creveld syndrome, an autosomal dominant skeletal dysplasia with atrial septal defects, and familial total anomalous pulmonary venous return, an autosomal dominant trait with reduced penetrance, were genetically linked to chromosomal bands 4p16 and 4p13-q12, respectively. The zebrafish has emerged as an important model for the study of the earliest stages of the cardiovascular system, and the miles apart and gridlock mutants, which have failure of heart tube fusion and aortic atresia, respectively, are discussed.

Animals↗
PubMed2001

Bipedicled fronto-occipital flap for reconstruction of postoncologic defects of the lateral scalp.

Presented here are two clinical cases of extensive defects of the scalp secondary to surgical resection of invasive basal cell carcinoma on the parietal region, successfully treated by means of very large, bipedicled fronto-occipital flaps, based anteriorly on the supratrochlear-supraorbital vessels and posteriorly on the occipital and posterior auricular vessels. Considering both the location and the large size of the scalp defects, different surgical techniques are discussed and the potential use of bipedicled scalp flaps is considered, designed either sagittally or coronally as fronto-occipital or temporo-temporal flaps. The bipedicled fronto-occipital scalp flap is believed to represent a simple, secure, and useful reconstructive procedure for cutaneous coverage of extensive defects located on the lateral scalp.

Aged↗
PubMed2004

Free flap transfer for closure and interposition-arthroplasty in noma defects of the lateral face associated with bony ankylosis.

Noma defects of the anterolateral face are often associated with fibrous or bony ankylosis fusing the mandibula to the skull base. According to the extent of the ankylosis, the temporomandibular joint mobility can be restricted or even completely frozen. In third world conditions the surgical approach to severe forms of bony ankylosis consists of a single linear opening osteotomy (trismus release) and the closure of the noma defect with locoregional flaps. Relapse of jaw immobility is common and may be caused by minor bone resection, the lack of adequate postoperative physiotherapy, or even the scarring of the defect coverage. In 4 years the authors have gained increasing experience with folded free flaps for simultaneous closure of outer and inner lining of large noma defects and the maintenance and training of re-established jaw function by the use of a dynamic external distractor fixed between the zygoma and the mandibular body. The authors report the bony reankylosis can be reduced by extended wedge osteotomies of the bony bridge and tip-like shaping of the ascending mandibular ramus. To preclude the reossification of the osteotomy site and fibrous scar formation, a dermofatty or muscular tail of the free flap is interposed into the bone gap. Two cases were treated according to this concept with a free parascapular and a latissimus dorsi flap in combination with simultaneous arthroplasty. During a 6-month follow-up period, no signs of a recurrent reduction of mandibular movement were noted in either case.

Adolescent↗
PubMed2006

A role for ethylene in the phytochrome-mediated control of vegetative development.

Members of the phytochrome family of photoreceptors play key roles in vegetative plant development, including the regulation of stem elongation, leaf development and chlorophyll accumulation. Hormones have been implicated in the control of these processes in de-etiolating seedlings. However, the mechanisms by which the phytochromes regulate vegetative development in more mature plants are less well understood. Pea (Pisum sativum) mutant plants lacking phytochromes A and B, the two phytochromes present in this species, develop severe defects later in development, including short, thick, distorted internodes and reduced leaf expansion, chlorophyll content and CAB gene transcript level. Studies presented here indicate that many of these defects in phyA phyB mutant plants appear to be due to elevated ethylene production, and suggest that an important role of the phytochromes in pea is to restrict ethylene production to a level that does not inhibit vegetative growth. Mutant phyA phyB plants produce significantly more ethylene than WT plants, and application of an ethylene biosynthesis inhibitor rescued many aspects of the phyA phyB mutant phenotype. This deregulation of ethylene production in phy-deficient plants appears likely to be due, at least in part, to the elevated transcript levels of key ethylene-biosynthesis genes. The phytochrome A photoreceptor appears to play a prominent role in the regulation of ethylene production, as phyA, but not phyB, single-mutant plants also exhibit a phenotype consistent with elevated ethylene production. Potential interactions between ethylene and secondary plant hormones in the control of the phy-deficient mutant phenotype were explored, revealing that ethylene may inhibit stem elongation in part by reducing gibberellin levels.

Ethylenes↗
PubMed1997

The Drosophila bifocal gene encodes a novel protein which colocalizes with actin and is necessary for photoreceptor morphogenesis.

Photoreceptor cells of the Drosophila compound eye begin to develop specialized membrane foldings at the apical surface in midpupation. The microvillar structure ultimately forms the rhabdomere, an actin-rich light-gathering organelle with a characteristic shape and morphology. In a P-element transposition screen, we isolated mutations in a gene, bifocal (bif), which is required for the development of normal rhabdomeres. The morphological defects seen in bif mutant animals, in which the distinct contact domains established by the newly formed rhabdomeres are abnormal, first become apparent during midpupal development. The later defects seen in the mutant adult R cells are more dramatic, with the rhabdomeres enlarged, elongated, and frequently split. bif encodes a novel putative protein of 1063 amino acids which is expressed in the embryo and the larval eye imaginal disc in a pattern identical to that of F actin. During pupal development, Bif localizes to the base of the filamentous actin associated with the forming rhabdomeres along one side of the differentiating R cells. On the basis of its subcellular localization and loss-of-function phenotype, we discuss possible roles of Bif in photoreceptor morphogenesis.

Actins↗