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PubMed2006

Repair of articular cartilage lesions in aged chickens by allogeneic transplantation of fresh embryonic epiphyses.

INTRODUCTION: The potential of fresh whole chick epiphyses of embryonic origin to serve as implant material for cartilage defects of aged chicken was tested. MATERIALS AND METHODS: Fresh epiphyses of 11-day-old embryos were collected from 24 animals and transplanted into defects created in the weight-bearing areas of tibiotarsal joint cartilage of 2-year-old chicks. Upon sacrifice, samples were examined macroscopically and microsections were prepared for histology. RESULTS: Macroscopically, control defects remained empty at all the time intervals. Defects of the experimental group were, on the other hand, filled with cartilaginous tissue as early as 2 weeks posttransplantation, although individual epiphyses could still be noted in the implant tissue. At 4 weeks and later, defects were filled with cartilaginous material indistinguishable from hyaline cartilage. Histologically, all grafts remained within the defect's pits, showing mitotic and metabolic activity typical to proliferating hyaline cartilage. The engrafted epiphyses showed a partial incorporation and integration with the surrounding host tissues already at 2 weeks. At 4 weeks and later, the integration was complete. CONCLUSIONS: It is concluded that a chick embryonic epiphyseal cartilage is suitable as a graft source for articular cartilage transplantation. The embryonic epiphyses provide immediate inherent stability to the graft and supply a good mix of mesenchymal progenitor cells responsible for the high rate of cell proliferation and adhesion to the differentiated committed chondrocytes of the host that create the typical favorable chondrogenic milieu. Based on the present findings, it is postulated that human embryonic epiphyses may, in the future, represent an alternative source to the commonly used techniques of hyaline cartilage repair.

Animals↗
PubMed1975

Rare and combined vertebrobasilar dysplasias related to vascular maldevelopment at different embryonal stages.

Angiographically demonstrated combined and complex angiodysplasias of the vertebrobasilar system are rare. As in our case, they can be attributed to a vascular maldevelopment in several consecutive embryonal stages: the angioma-like arterial network of the left posterior cerebral artery and the non-union and overcrossing of the vertebral arteries in the region of the prepontine cistern represent an early defect (up to 15 mm stage); the aneurysmatic ectasia of the right vertebral artery with a second pedunculated aneurysm at its uppermost part may be due to a later defect (up to 40 mm stage) of the cerebral vascular development.

Adult↗
PubMed2000

Smad5 is essential for left-right asymmetry in mice.

Left-right (L-R) asymmetry of the vertebrate body plan is established from an originally morphologically symmetric embryo. Recent studies have implicated several TGF-beta family signaling proteins (i.e., nodal, lefty-1, lefty-2, activin receptor type IIB, and Smad2) in L-R axis determination in the mouse. However, the genetic pathways underlying L-R patterning are still unclear. Smad5 is a downstream component in the TGF-beta family signaling cascade, and lack of Smad5 results in embryonic lethality between E9.5 and E11.5. In this report, we demonstrate that Smad5 mutant embryos have defects in heart looping and embryonic turning which are the first signs of L-R asymmetry in mice. To gain more insights into the molecular basis of the laterality defects in the Smad5-deficient embryos, we examined the expression of lefty-1, lefty-2, nodal, and Pitx2 since the asymmetric expression of these genes always closely correlates with the direction of heart looping and embryonic turning. In the absence of Smad5, lefty-1 was expressed at very low or undetectable levels, while nodal, lefty-2, and Pitx2 were expressed bilaterally. These data suggest that Smad5 is upstream of lefty-1, nodal, and lefty-2, and as a consequence also of Pitx2, and Smad5 is essential for L-R axis determination.

Animals↗
PubMed2002

Analysis of protein localization and secretory pathway function using the yeast Saccharomyces cerevisiae.

The isolation and characterization of mutants has been crucial in understanding a number of processes in the field of cell biology. In this exercise, students examine the effects of mutations in the secretory pathway on protein localization. Yeast strains deficient for synthesis of histidinol dehydrogenase are transformed with a plasmid encoding a chimeric protein. The chimera contains a signal sequence fused to histidinol dehydrogenase. A strain with a defect in the translocation of secretory proteins into the endoplasmic reticulum (ER) accumulates sufficient histidinol dehydrogenase in the cytoplasm to grow on media lacking histidine. In contrast, yeast proficient for secretion, or yeast with secretion defects later in the pathway, are unable to grow on media lacking histidine. Student analysis of the experimental yeast transformants and appropriate controls allows investigation into the effects of conditional defects in the secretory pathway on both cell viability and protein localization. The exercise is usually performed in a manner that allows students to execute a number of techniques common in molecular biology laboratories, including plasmid minipreps, restriction digestions, and Southern blots. Student understanding and enjoyment of the exercise was assessed by laboratory reports, oral and written examinations, and questionnaires. After completion of these experiments, students can describe the utility of protein fusions, the roles of mutant analysis in cell biology, and the steps taken by proteins transiting the secretory pathway.

Biology↗
PubMed1999

The SIL gene is required for mouse embryonic axial development and left-right specification.

The establishment of the main body axis and the determination of left-right asymmetry are fundamental aspects of vertebrate embryonic development. A link between these processes has been revealed by the frequent finding of midline defects in humans with left-right anomalies. This association is also seen in a number of mutations in mouse and zebrafish, and in experimentally manipulated Xenopus embryos. However, the severity of laterality defects accompanying abnormal midline development varies, and the molecular basis for this variation is unknown. Here we show that mouse embryos lacking the early-response gene SIL have axial midline defects, a block in midline Sonic hedgehog (Shh) signalling and randomized cardiac looping. Comparison with Shh mutant embryos, which have axial defects but normal cardiac looping, indicates that the consequences of abnormal midline development for left-right patterning depend on the time of onset, duration and severity of disruption of the normal asymmetric patterns of expression of nodal, lefty-2 and Pitx2.

Animals↗
PubMed1977

Tension free closure of large meningomyelocele defects.

A technique for closing large meningomyelocele defects without tension has recently been developed by the authors. The technique utilizes bilateral bipedicle flaps developed from verticle flank incisions. The bipedicle flaps are advanced medially and approximated in the midline. The lateral defects created by this maneuver are closed transversely. The outer margins of the bipedicle flaps are left free until the flaps become adherent to the underlying tissue. This technique has been used in the repair of 12 large meningomyeloceles. The width of the average lesion was 6-7 centimeters, the largest lesion was 11 centimeters. In each case the width of the lesion exceeded one-half the width of the back. In all cases a tension free closure was achieved. There were no significant wound complications. The use of this technique has greatly facilitated the treatment of children with large meningomyelocele defects.

Humans↗
PubMed1988

Alterations in myocardial thallium-201 distribution in patients with chronic systemic hypertension undergoing single-photon emission computed tomography.

To characterize thallium-201 distribution in single-photon emission computed tomography (SPECT) cardiac images and polar bullseye maps, 100 patients with chronic systemic hypertension due to end-stage renal disease were studied and the results compared with those in 35 normotensive control subjects. Thallium-201 SPECT was performed after exercise in all control subjects and 70 hypertensive patients, and after intravenous dipyridamole in 30 patients. A frequent finding in hypertensive patients was a fixed decrease in the normal lateral-to-septal count density ratio in immediate thallium-201 SPECT images (1.02 +/- 0.10 vs 1.17 +/- 0.08 in control subjects, p less than 0.00001) and in 3-hour delayed images (1.02 +/- 0.11 vs 1.11 +/- 0.08 in control subjects, p less than 0.00001). No significant difference in count density ratio was present in patients undergoing treadmill versus diypridamole intervention. In 35 patients the count density ratio was greater than 2.0 standard deviations below the normal mean, creating the false impression of a fixed lateral defect (i.e., myocardial infarction). In 12 patients, myocardial wall thickness was measured at end-diastole by 2-dimensional echocardiography. Wall thickness was increased (greater than 11 mm) in all patients. The mean lateral-to-septal wall thickness ratio was 1.08 +/- 1.11; in no patient was the ratio less than 0.76 to indicate selective septal hypertrophy. The lateral-to-septal wall thickness and lateral-to-septal thallium-201 count density ratios correlated poorly (r = 0.43).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomegaly↗
PubMed2004

Cilia, primary ciliary dyskinesia and molecular genetics.

Primary ciliary dyskinesia (PCD) is a phenotypically and genetically heterogeneous condition in which three genetic mutations have already been identified. The primary defect is in the ultrastructure or function of cilia, highly complex organelles that are structurally related to the flagella of sperm and protozoa. The clinical features of PCD include recurrent sinopulmonary infections, subfertility and laterality defects; the latter due to ciliary dysfunction at the embryological node. Completion of the human genome sequence has accelerated the identification and characterisation of disease genes, and the current molecular strategy in PCD includes candidate gene analysis, positional cloning, model organism analysis and proteomic analysis. The identification of these genes will provide new insights into the molecular mechanisms involved in the assembly and function of cilia and the pathway that determines left-right axis in man. This may also allow the development of new methods for diagnosis, prevention and treatment of PCD.

Animals↗
PubMed2004

A case report of polysplenia syndrome associated with genital tract duplication anomaly.

Polysplenia syndrome is a condition that persists as a defect of lateralisation, the embryonic process by which the site of body organs is determined. The most frequent manifestations of this syndrome, in addition to polysplenia are complex cardiac malformations, situs inversus, and bilobed lungs. Laterality defects have been known to be due to autosomal recessive inheritance. We report a unique case of polysplenia syndrome in association with genital tract duplication anomaly.

Abnormalities, Multiple↗
PubMed1998

Patterning the heart's left-right axis: from zebrafish to man.

Normal left-right asymmetry is highly conserved among vertebrates. Errors in the proper patterning of this axis are believed to lead to congenital anomalies of the heart and abdominal viscera, often with profound clinical consequences. We review briefly the nature of potential signals and signaling sources that lead to the break in left-right symmetry. The evidence suggests that left-right reversal, or homogenization, of these signals may lead to different consequences, and we explain some malpositions and malalignments of the atria, ventricles, and/or outflow tract that are seen in a variety of congenital cardiac diseases. We speculate that there are units of organ assembly responsive to laterality signals, and these units may be driven independently. One crucial source of signals appears to be the notochord and floorplate. In order to examine the clinical relationship of these midline structures to putative disorders of laterality, we review all patients with disturbances of normal laterality seen at the Massachusetts General Hospital over the past 20 years. We find a significant association between laterality defects and anomalies of the spine and other midline structures.

Animals↗
PubMed1974

Viral DNA synthesis in cells infected by temperature-sensitive mutants of simian virus 40.

Temperature-sensitive mutants of simian virus 40 (SV40) have been classified as those that are blocked prior to viral DNA synthesis at the restrictive temperature, "early" mutants, and those harboring a defect later in the replication cycle, "late" mutants. Mutants of the A and D complementation groups are early, those of the B, C, and BC groups are late. Our results confirm earlier reports that A mutants are defective in a function required for the initiation of each round of viral DNA synthesis. D mutants, on the other hand, continue viral DNA replication at the restrictive temperature after preincubation at the permissive temperature. The length of time required for D function to be expressed at the permissive temperature-after which infection proceeds unabated on shifting of the cultures to the restrictive temperature-is 10 to 20 h. The viral DNA synthesized in D mutants under these conditions progresses in normal fashion through replicative intermediate molecules to mature component I and II DNA molecules.

Animals↗
PubMed2003

[Late manifestations of congenital diaphragmatic hernia].

The aim of the work was to evaluate clinical and anatomical features in children with late manifestations of inborn diaphragma hernia after the newborn period. The group included 11 boys and 7 girls at the age of two to 78 months during the time of diagnosis. The diaphragma hernia was diagnosed in 15 children during non-acute manifestations and in three children affected by emergencies. A posterior-lateral defect of diaphragma was on the left side in 11 children and in 7 children on the left. A hernia sac was found in 11 children. Organs protruding into thorax included intestinal loops in 12 children, liver in 7 subjects, spleen in 6 individuals, stomach in five and kidney, pancreas and omentum in one each. The defect in diaphragma was occluded by a primary plasty in 17 children, while a patch from Goretex was used once. An intestinal strangulation required resection of necrotic part of intestine, but the boy died one month later for a multi-organ failure despite long-term resuscitation care. The other children were cured up without complications. The inborn diaphragma hernia should be considered in differential diagnosis of every child with unusual respiratory or gastrointestinal symptoms and abnormal X-ray picture of thorax. Acute strangulation of inborn diaphragma hernia after the newborn period is a life-threatening disease, where the gastrointestinal obstruction is combined with respiratory and circulation failure.

Child, Preschool↗
PubMed1978

Complex pulmonary atresia with congenital systemic collaterals. Classification and management.

80 patients with pulmonary atresia and subaortic ventricular septal defect had complete angiography with right ventricular, aortic and selective arterial angiograms to delineate the anatomy of the central pulmonary arteries and the systemic supply to the lungs, as correct management of the patient depends on this. In 67 (85 p. 100) there were 1-5 large congenital systemic collateral arteries mainly arising at or below the aortic isthmus. This group, referred to as "complex pulmonary atresia" with right aortic arch in 30, had variable central pulmonary artery development, either completely absent in 17, hypoplastic in 33 (49 p. 100) appearing as a "seagull" (une mouette) in the mediastinum on late films or large well developed vessels in 17. Patients with hypoplastic central arteries require special management. We now perform a two stage procedure, initially placing a conduit containing a homograft aortic valve between the right ventricle and small central pulmonary arteries in order to develop them and leaving the ventricular septal defect open. Initial results in 6 patients treated this way are encouraging and it is proposed to close the defect later after enlargment of the pulmonary arteries has occurred.

Adolescent↗
PubMed2005

Roles for fgf8 signaling in left-right patterning of the visceral organs and craniofacial skeleton.

Laterality is fundamental to the vertebrate body plan. Here, we investigate the roles of fgf8 signaling in LR patterning of the zebrafish embryo. We find that fgf8 is required for proper asymmetric development of the brain, heart and gut. When fgf8 is absent, nodal signaling is randomized in the lateral plate mesoderm, leading to aberrant LR orientation of the brain and visceral organs. We also show that fgf8 is necessary for proper symmetric development of the pharyngeal skeleton. Attenuated fgf8 signaling results in consistently biased LR asymmetric development of the pharyngeal arches and craniofacial skeleton. Approximately 1/3 of zebrafish ace/fgf8 mutants are missing Kupffer's vesicle (KV), a ciliated structure similar to Hensen's node. We correlate fgf8 deficient laterality defects in the brain and viscera with the absence of KV, supporting a role for KV in proper LR patterning of these structures. Strikingly, we also correlate asymmetric craniofacial development in ace/fgf8 mutants with the presence of KV, suggesting roles for KV in lateralization of the pharyngeal skeleton when fgf8 is absent. These data provide new insights into vertebrate laterality and offer the zebrafish ace/fgf8 mutant as a novel molecular tool to investigate tissue-specific molecular laterality mechanisms.

Animals↗
PubMedDate not supplied

[Cranio-facial resections].

Four basic steps should be considered in craniofacial tumor surgery: dismantling and re-assembling of preservable bone structures to reach the tumor; en bloc resection of the "box" in malignancies (i.e., the unaffected boundaries surrounding and including the tumor), internal rigid fixation and, reconstruction by using whenever possible regional structures. In benign tumors and so-called pseudotumors, the treatment is total removal and immediate reconstruction of all structures, including the bone. The primary goal of craniofacial surgery for malignancies is to create an entrance to the box that is to be resected. This necessitates the dismantling and reassembly of some uninvolved skeletal structures. Among these are the nose, the maxilla, the nose and maxilla en bloc, the nose and the maxilla bilaterally to the mandible. The introduction of internal rigid fixation by using plates and screws has facilitated the realignment of the pedicled bone fragments in a correct position. After cranial base resection, the communication between neuro- and splanchno-cranium must be closed with viable flaps. Many techniques have been described. The horizontal forehead flap is certainly effective but results in a significant secondary defect. Where there is an orbital resection en bloc with the cranial base, the temporalis muscle flap is effective in providing vascularized coverage and simultaneously obliterating the orbital cavity. The galeal frontal flap is versatile and easy to use. It has been used to cover anterior and lateral defects with good results. The orbit is another area that requires immediate reconstruction so that there is no resulting external defect. The temporalis muscle flap, with or without a skin island, can be used to repair it. Distant flaps can likewise be used. If the resection includes the maxilla, reconstruction of the defect can be performed immediately, or it can be delayed. The authors prefer to use the temporalis muscle flap if it has not already been used. On the basis of 10 years of experience in craniofacial surgery the following conclusions can be drawn: 1. Craniofacial surgery is not a single concept. Therefore, the surgeon who deals with facial tumors involving the cranial base must have expertise in the entire field. Oncology must be part of his basic biological education. 2. Complications functional and aesthetic consequences are minimal if some basic principles are applied, both in the resection and the primary reconstructive phase. 3. In the past few years, surgical techniques have been modified and improved considerably, resulting in an operation that combines an excellent approach, oncological resection, low postoperative morbidity, good aesthetic results and improved prognosis.

Facial Bones↗
PubMed2007

Genetic defects in ciliary structure and function.

Cilia, hair-like structures extending from the cell membrane, perform diverse biological functions. Primary (genetic) defects in the structure and function of sensory and motile cilia result in multiple ciliopathies. The most prominent genetic abnormality involving motile cilia (and the respiratory tract) is primary ciliary dyskinesia (PCD). PCD is a rare, usually autosomal recessive, genetically heterogeneous disorder characterized by sino-pulmonary disease, laterality defects, and male infertility. Ciliary ultrastructural defects are identified in approximately 90% of PCD patients and involve the outer dynein arms, inner dynein arms, or both. Diagnosing PCD is challenging and requires a compatible clinical phenotype together with tests such as ciliary ultrastructural analysis, immunofluorescent staining, ciliary beat assessment, and/or nasal nitric oxide measurements. Recent mutational analysis demonstrated that 38% of PCD patients carry mutations of the dynein genes DNAI1 and DNAH5. Increased understanding of the pathogenesis will aid in better diagnosis and treatment of PCD.

Animals↗
PubMed2006

Reconstruction of orbital floor and maxilla with divided vascularised calvarial bone flap in one session.

We present four cases which underwent reconstruction of orbital floor and anterior maxillary wall with a vascularised bone flap following partial maxillectomy. After tumour resections, superficial temporal artery (STA) and vein based calvarial bone flaps from the outer tabula were prepared. Without disrupting the integrity of fascia and periosteum, the bone was separated into two segments in the same direction as the blood flow and one is 3 cm and the other 5 cm. The two bone segments were transferred as one single flap and one segment of the flap was used to reconstruct the orbital floor and the other for reconstruction of the anterior maxillary wall. Since two cases had large skin defects, lateral frontal skin to which the frontal branch of the STA supplies blood was incorporated into the flaps. Functional and aesthetic results were satisfactory at the end of 8-20 months follow-up. This technique allowed reconstruction of the orbital floor and anterior maxillary wall and even skin defects with a single pedicled flap in one session.

Adolescent↗
PubMed2001

The influence of static and dynamic loading on marginal bone reactions around osseointegrated implants: an animal experimental study.

Although it is generally accepted that adverse forces can impair osseointegration, the mechanism of this complication is unknown. In this study, static and dynamic loads were applied on 10 mm long implants (Brånemark System, Nobel Biocare, Sweden) installed bicortically in rabbit tibiae to investigate the bone response. Each of 10 adult New Zealand black rabbits had one statically loaded implant (with a transverse force of 29.4 N applied on a distance of 1.5 mm from the top of the implant, resulting in a bending moment of 4.4 Ncm), one dynamically loaded implant (with a transverse force of 14.7 N applied on a distance of 50 mm from the top of the implant, resulting in a bending moment of 73.5 Ncm, 2.520 cycles in total, applied with a frequency of 1 Hz), and one unloaded control implant. The loading was performed during 14 days. A numerical model was used as a guideline for the applied dynamic load. Histomorphometrical quantifications of the bone to metal contact area and bone density lateral to the implant were performed on undecalcified and toluidine blue stained sections. The histological picture was similar for statically loaded and control implants. Dense cortical lamellar bone was present around the marginal and apical part of the latter implants with no signs of bone loss. Crater-shaped bone defects and Howship's lacunae were explicit signs of bone resorption in the marginal bone area around the dynamically loaded implants. Despite those bone defects, bone islands were present in contact with the implant surface in this marginal area. This resulted in no significantly lower bone-to-implant contact around the dynamically loaded implants in comparison with the statically loaded and the control implants. However, when comparing the amount of bone in the immediate surroundings of the marginal part of the implants, significantly (P < 0.007) less bone volume (density) was present around the dynamically loaded in comparison with the statically loaded and the control implants. This study shows that excessive dynamic loads cause crater-like bone defects lateral to osseointegrated implants.

Animals↗