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At least 451 records · Page 25Linked to original sources
PubMed2000

[Nonsurgical occlusion of an atrial septal defect in childhood: initial Swiss experiences].

The initial experience with catheter closure of an atrial septal defect (ASD) in children, performed at two Swiss centers is presented. The ASD closures were performed according to international multicenter study protocols. 14 children, aged 3.9-17.5 years underwent closure by catheter. The defect size varied between 12 and 22 mm (balloon sized), the ratio between pulmonary and systemic blood flow showed a mean of 2.2 (1.5-3.5). Catheter closure was done using three different occlusion devices. More recently only the Amplatzer occluder was used at both institutions. In 12 children (86%) defect closure was successful and after a follow-up of 3-32 months (mean 17) only one child had a trivial residual interatrial shunt. In all children, echocardiographic follow-up showed an unchanged and correct device position on both sides of the atrial septum. In two children, a floppy aortic segment of the atrial septal rim led to instable device position: both children underwent surgical defect closure later. The children with successful device closure showed no complications during the catheterization or during follow-up. There were no thrombotic complications on the surfaces of the devices. Catheter closure of an ASD during childhood is a safe and efficient alternative to standard surgical treatment.

Adolescent↗
PubMed1983

The versatility of the lateral tongue flap in the reconstruction of defects of the oral cavity.

The full thickness, posteriorly based, lateral tongue flap is described and the excellence of the blood supply is emphasised. The surgical technique is discussed and the application of the flap in the reconstruction of defects of the palate, cheek and floor of the mouth is illustrated. The versatility of the method is stressed, together with advantages over regional skin flaps when used for the same purpose.

Adult↗
PubMed2005

The composite vastus medialis-patellar complex osseomuscular flap as a salvage procedure after complex trauma of the knee--an anatomical study and clinical application.

BACKGROUND: In the setting of severe perigenicular trauma or complicated endoprosthetic knee surgery, primary knee fusion may be the last resort for salvage of the limp. In this case, the patella looses its destination as an anterior knee stabilizer and can become a substantial donor of bone substance, especially if osseous defects are involved. PATIENTS AND METHODS: 12 formalin fixated cadavers were studied in terms of vascular anatomy, pedicle reliability, arc of rotation and their relation to sex, age, and height. Moreover, the operation was performed on a suitable patient. RESULTS: The quadriceps with the vastus medialis and the patella can be raised from the tibial tuberosity up to the entrance of the osteoarticular branch of the superficial femoral artery into the vastus medialis muscle ca 16 cm (15-19 cm) from the inferior patellar pole. This distance correlated well to the overall height of the cadavers (P=0.009). The vascular prerequisites were always present. In the clinical case, there was a favorable outcome with knee fusion after 4 months, despite of the lateral condylar defect. DISCUSSION: The composite vastus medialis-patellar complex osseomuscular flap can be safely used as a source of vascularized femoral condyle substitute in the setting of primary knee fusion.

Arteries↗
PubMed1989

False-positive acetylcholinesterase with early amniocentesis.

Among 93 acetylcholinesterase determinations performed on amniotic fluid samples from pregnancies at 11-14 weeks' gestation, five unexplained false-positive results were observed. In four of the five cases, the ratio of acetylcholinesterase to pseudocholinesterase was compatible with that observed in association with open neural tube defects in later gestation. In contrast, no false-positive results were noted among 951 acetylcholinesterase determinations performed on samples from women at 15-20 weeks' gestation. Repeat amniocentesis was performed several weeks after the first procedure in four of the five cases of early amniocentesis and false-positive results; in each case, the acetylcholinesterase was negative on the second sample. All four pregnancies had a normal outcome. In the remaining case, trisomy 21 was diagnosed in the fetus and the pregnancy was terminated. Positive acetylcholinesterase results should be interpreted cautiously in samples from early amniocentesis, especially when the amniotic fluid alpha-fetoprotein level is not markedly elevated. The acetylcholinesterase-to-pseudocholinesterase ratio is not useful in identifying fetal neural tube defects before 15 weeks' gestation. Repeat amniocentesis may help in determining the significance of a positive acetylcholinesterase result from early amniocentesis when no fetal defect is identified by ultrasonography.

Acetylcholinesterase↗
PubMed1998

Intramedullary versus extramedullary fixation of subtrochanteric fractures. A biomechanical study.

We compared two different subtrochanteric fracture fixation techniques, an intramedullary hip screw system (IMHS) and an extramedullary, dual sliding screw-plate system (MSP), to determine relative fixation stability. 6 matched pairs of osteosynthesized osteopenic cadaver femurs were axially loaded to 1000 N with concurrent, simulated abductor forces of 0%, 50%, or 86% of the applied head force. The initial loading sequence was made with uniaxial dynamization--the lag screw of the MSP locked and distal locking of the IMHS nail. Femoral head displacement and medial femoral strain were measured for intact femur controls, after fixation of a 2-part reverse oblique subtrochanteric fracture and finally a 3-part reverse oblique subtrochanteric fracture with a lateral wedge defect. The samples were then loaded at 750 N for 10(4) cycles with both devices uniaxially locked, followed by 10(4) cycles with both devices fully biaxially dynamized (unlocked). For the 2-part subtrochanteric fracture pattern, both devices exhibited similar inferior displacements of the femoral head (average 2.0 mm) and medial femoral strain (approximately 70% of intact). Increasing abductor forces decreased medial compressive strain but did not significantly affect head displacement. For the 3-part fracture model, the MSP demonstrated significantly less inferior displacement of the head (1.6 mm vs. 2.1 mm) and both devices demonstrated significantly decreased medial strain. After cycling, head displacement increased approximately 50% in both devices and medial strain increased slightly. After unlocking and cycling, the MSP group showed significant lateral displacement of the proximal fragment. The IMHS and MSP devices provide similar stability for fixation of 2-part and 3-part reverse oblique subtrochanteric fractures. In a biaxially dynamized, 3-part reverse oblique fracture, displacement of the proximal fragment can occur with the MSP.

Aged↗
PubMed2004

Laterally moved, coronally advanced flap: a modified surgical approach for isolated recession-type defects.

BACKGROUND: Various modifications of the laterally sliding flap have been proposed to reduce the risk of gingival recession at the donor tooth site, but the reported root coverage predictability was quite low. The goal of the present study was to evaluate the effectiveness with respect to root coverage of a modified surgical approach of the laterally moved flap procedure for the treatment of an isolated type of recession defect. METHODS: One hundred and twenty (120) isolated gingival recessions (Miller Class I or II) with specific features of the keratinized tissue lateral to the defects were treated with a new approach to the laterally moved flap. The main surgical modifications consisted of the coronal advancement of the laterally moved flap and the different thickness during flap elevation. Clinical evaluation was made 1 year after the surgery. RESULTS: At the 1-year examination, 97% of the root surface was covered with soft tissue and 96 defects (80%) showed complete root coverage. A statistical and clinically significant increase of keratinized tissue was observed. These favorable results were accomplished with no change in the position of gingival margin or in the height of gingival tissue at the donor tooth/site. CONCLUSIONS: The laterally moved, coronally advanced surgical technique was very effective in treating isolated gingival recessions. It combined the esthetic and root coverage advantages of the coronally advanced flap with the increase in gingival thickness and keratinized tissue associated with the laterally moved flap. The ideal gingival conditions must be present lateral to an isolated recession defect in order to render the proposed surgical technique an highly effective and predictable root coverage surgical procedure.

Chlorhexidine↗
PubMed2003

Histological study of experimental reconstructive materials for repair of lateral skull base and dura mater defects in dogs.

OBJECTIVE: In order to assess the reconstructive properties of fascia lata, superficial fascia lata and bone morphogenetic protein (BMP) in skull base surgery, lateral skull base bone and dura mater defect models were established in dogs MATERIAL AND METHODS: As a repair material we selected fascia lata, either alone or in combination with BMP, for reconstructing large cranial defects in dogs. Twenty dogs undergoing a 3.0 x 4.0 cm2 full-thickness excision of the parietal bone were divided into four equal groups as follows: fascia lata reconstruction; fascia lata reconstruction plus BMP; controls; and fascia lata reconstruction plus BMP with direct exposure of fascia lata. The implants were harvested at 2-15 weeks and examined histologically. Results-Treated and untreated implants were quite different: formation of new bone occurred in the dogs treated with BMP whereas the unreconstructed controls demonstrated only a bridge of fibrovascular connective tissue. CONCLUSION: The results of this study suggest that it is better to combine BMP and reconstructive material for the treatment of bone defects.

Animals↗
PubMed1997

Retarded formation of the hippocampal commissure in embryos from mouse strains lacking a corpus callosum.

A precise description of the timing and route traveled by axons traversing the telencephalic midline through the ventral hippocampal commissure (HC) is essential for understanding the role it plays in the formation of the corpus callosum (CC). A normal baseline of HC development was described in B6D2F2 hybrid mice and then compared with two inbred strains of mice displaying callosal agenesis, BALB/cWah1 (50% CC defect) and 129/J (70% CC defect), their F2 hybrid (C129F2-33% CC defect), and a recombinant inbred strain (RI-1-100% CC defect) derived from pairs of C129F2 mice. Embryos weighing from 0.25 g to 0.70 g (E14.5-E17) were collected and fixed by perfusion. Axon tracts were labeled using crystals of the lipophilic dyes DiI and DiA inserted into the hippocampal fimbria and cerebral cortex. HC axons in B6D2F2 mice first cross the midline at about 0.350 g body weight (E14.8) by traveling over the dorsal septum and along the pia membrane lining the longitudinal fissure. Earlier crossing was prevented by the presence of a deep cleft formed by the longitudinal fissure extending down into the septal region. Subsequent axons fasciculated along existing axons, gradually building the dorsoventral height of the HC to about 200 microns by 0.600 g. The earliest callosal axons from frontal cortex crossed the midline at 0.620 g and were clearly seen fasciculating along and between existing hippocampal axons at the dorsal surface of the HC as they crossed. In the acallosal strains, HC formation was delayed by the continued presence of the cleft deep in the septal region. This delay in time of crossing was correlated with later CC defect expression. Initial HC crossing occurred at about 0.470 g (E16.25) in BALB mice and about 0.520 g (E16.5) in 129 mice. In the RI-1 embryos, first HC crossing was estimated at about 0.750 g (E17.5), although several older embryos showed no crossing. These results show the importance of the HC for successful CC formation and suggest that absent CC arises as a consequence of a developmental defect which affects the formation of the hippocampal commissure prior to arrival of CC axons at midplane.

Agenesis of Corpus Callosum↗
PubMed2003

A dominant negative mutant of TLK1 causes chromosome missegregation and aneuploidy in normal breast epithelial cells.

BACKGROUND: In Arabidopsis thaliana, the gene Tousled encodes a protein kinase of unknown function, but mutations in the gene lead to flowering and leaf morphology defects. We have recently cloned a mammalian Tousled-Like Kinase (TLK1B) and found that it phosphorylates specifically histone H3, in vitro and in vivo. We now report the effects that overexpression of a kinase-dead mutant of TLK1B mediates in a normal diploid cell line. RESULTS: Expression of a kinase-dead mutant resulted in reduction of phosphorylated histone H3, which could have consequences in mitotic segregation of chromosomes. When analyzed by FACS and microscopy, these cells displayed high chromosome number instability and aneuploidy. This phenomenon was accompanied by less condensed chromosomes at mitosis; failure of a number of chromosomes to align properly on the metaphase plate; failure of some chromosomes to attach to microtubules; and the occasional presentation of two bipolar spindles. We also used a different method (siRNA) to reduce the level of endogenous TLK1, but in this case, the main result was a strong block of cell cycle progression suggesting that TLK1 may also play a role in progression from G1. This block in S phase progression could also offer a different explanation of some of the later mitotic defects. CONCLUSIONS: TLK1 has a function important for proper chromosome segregation and maintenance of diploid cells at mitosis in mammalian cells that could be mediated by reduced phosphorylation of histone H3 and condensation of chromosomes, although other explanations to the phenotype are possible.

Aneuploidy↗
PubMed2006

Reflux nephropathy in kidney transplants, demonstrated by dimercaptosuccinic acid scanning.

BACKGROUND: This study determines why kidney transplants develop new focal defects. METHODS: Thirty children at a U.K. pediatric nephrology department receiving kidney transplants had early and late dimercaptosuccinic acid (DMSA) scans to detect acquired focal defects, and their presence correlated with possible risk factors. Associations between clinical events and focal DMSA lesions appearing in grafts were measured. RESULTS: Of the 30 early DMSA scans (within 2 weeks of function), one child with a thrombosed polar artery had a focal defect. On rescanning later, 11 (37%) had acquired segmental defects; five were multiple, and their glomerular filtration rates were 20 ml/min/1.73 m lower (95% CI 7-34). Histology in one case showed pyelonephritic scarring. Reflux into the transplant ureter occurred in 19/27 (70%) of children tested (by radiological or indirect radionuclide cystography). Nine of 13 children (69%) who had a combination of reflux and a urine infection had acquired scars, whereas only 1/14 (7%) did without this combination (P = 0.001). Scarring was not associated with the age or sex of the donor or recipient, rejection episodes, renal biopsy, or drug-induced nephrotoxicity. CONCLUSION: Kidney transplants are at high risk of developing segmental pyelonephritic scars if infected urine refluxes into the graft, either early through a transanastomotic stent or later from vesicoureteric reflux. These scars may reduce the renal function and are readily seen on DMSA, but not ultrasound scans. Consideration should be given to more effective antireflux surgery for transplants, with subsequent testing for reflux, urinary antibiotic prophylaxis, and prompt treatment of urine infections.

Adolescent↗
PubMed2000

Posterior scalping flap revisited.

OBJECTIVE: To report our experience in a case series of 5 posterior scalping flaps. DESIGN: Retrospective review of a case series. SETTING: A tertiary academic care otolaryngology-head and neck surgery referral center. PATIENTS: Five patients having undergone posterior scalping flap reconstruction of cutaneous midface defects. METHODS: Reconstruction was performed for 4 cheek defects, 1 of which included the lateral third of the upper and lower lips, and 1 combined midfacial and lateral nasal wall defect. RESULTS: All 5 patients had excellent cosmetic and functional results. The only complication was a single case of partial-thickness distal flap necrosis. CONCLUSION: The posterior scalping flap offers a reliable source of skin with appropriate color and texture and minimal donor-site morbidity.

Adult↗
PubMed1989

Hernia uterus inguinale associated with unicornuate uterus.

Hernia uterus inguinale, a condition in which endometrium and myometrium are found in an ectopic location in the inguinal canal, is a rare congenital abnormality in women. A woman with a normal number of chromosomes (46,XX) demonstrated the presence of a uterus, fallopian tube, and ovary in an inguinal hernia associated with a unicornuate uterus. This represents a unique abnormality in the spectrum of lateral fusion defects associated with müllerian ductal development, which normally proceeds as the right and left systems fuse and form the uterus, cervix, and four fifths of the vagina. In this patient, the left müllerian system apparently failed to fuse with the right, instead assuming a location within the patient's inguinal canal.

Abnormalities, Multiple↗
PubMed1997

Left-right asymmetry in vertebrate embryogenesis.

Embryonic development results in animals whose body plans exhibit a variety of symmetry types. While significant progress has been made in understanding the molecular events underlying the early specification of the antero-posterior and dorso-ventral axes, little information has been available regarding the basis for left-right (LR) differences in animal morphogenesis. Recently however, important advances have been made in uncovering the molecular mechanisms responsible for LR patterning. A number of genes (including well-known signaling molecules such as Sonic hedgehog and activin) are asymmetrically expressed in early chick embryos, well before the appearance of morphological asymmetries. One of these, nodal, is asymmetrically expressed in frogs and mice as well, and its expression is altered in mouse mutants exhibiting defects in laterality. In the chick, these genes regulate each other in a sequential cascade, which independently determines the situs of the heart and other organs.

Abnormalities, Drug-Induced↗
PubMed2003

RNA inhibition of BMP-4 gene expression in postimplantation mouse embryos.

Short, hairpin RNA (shRNA) directed against bone morphogenetic protein 4 (Bmp-4) was delivered to early postimplantation staged mouse embryos via tail vein injection of pregnant dams. As early as 24 h postinjection, embryos expressed a DsRed marker and later exhibited defects of neural fold elevation and closure and of cardiac morphogenesis. Immunohistochemical analysis of sectioned embryos indicated that Bmp-4 protein was depleted and gene expression analysis indicated there was a reduction in Bmp-4 mRNA and an upregulation of the Bmp-4 antagonists, noggin and chordin, in embryos exposed to the shRNA, but not in control embryos. There was no change in the expression of Gata4, brachyury, or claudin6 in RNAi exposed embryos, indicating that RNA silencing was specific to Bmp-4 rather than producing widespread gene inhibition. Delivery of shRNA to embryos has the potential to specifically knockdown the expression of developmentally essential genes and to rescue gene mutations, significantly decreasing the time required to analyze the function(s) of individual genes in development.

Animals↗
PubMed2007

Fracture of titanium plates used for mandibular reconstruction following ablative tumor surgery.

PURPOSE: The purpose of this study was to identify reasons for fracture of titanium mandibular reconstruction plates, when used to bridge lateral mandibular defects after ablative tumor surgery. MATERIALS AND METHODS: Sixteen titanium reconstruction plates from sheep mandibles were examined to identify reasons for the plate fractures. The broken plates and the seemingly unbroken plates were examined separately. The plates were removed from the mandibular bone and inspected by dye penetrant examination, metallography, optical microscope, scanning electron microscope, and energy dispersive X-ray spectrometer. Furthermore, axial load fatigue tests were performed in two different environments, air and physiologic salt solution, 0.9% NaCl, to compare titanium behavior in air and the human body. RESULTS: The site of crack initiation was the inner curvature of the reconstruction plate, and the cracks initiated as a result of stress concentration in the shoulder fillet of the plate. The cracks grew in a cyclic manner under masticatory loading of the mandible and the plate. The plate fracture occurred by means of fatigue. The corrosive environment did not affect the failure of the titanium plate, and the fracture was not caused by hydrogen embrittlement. The results revealed that the fatigue properties of the plates may have been impaired by the residual stresses generated in plate bending. CONCLUSIONS: Adjustive bending of the plates, in the surgical operation, may thus be an important cause of fracture of the reconstruction plates, because of generated residual stresses, which affect the mean stress in fatigue loading. To make the plates function without failure the plates should match closely with the three-dimensional shape of the mandible, to avoid any bending in the operative phase.

Animals↗
PubMed2002

Molecular analysis of genomic DNA allows rapid, and accurate, prenatal diagnosis of peroxisomal D-bifunctional protein deficiency.

Prenatal diagnosis was requested for a couple with a previous child affected by the peroxisomal disorder D-bifunctional protein deficiency. Prior analysis of the D-bifunctional protein cDNA sequence from the propositus had shown that it was missing 22 bp. This was subsequently attributed to a point mutation in the intron 5 donor site (IVS5 + 1G>C) of the D-bifunctional protein gene. Consistent with parental consanguinity, the patient was shown to be homozygous for this mutation, which is associated with loss of a Hph 1 restriction site in the genomic sequence. Prenatal testing of the fetus using genomic DNA isolated from uncultured amniocytes indicated that both alleles of the D-bifunctional protein had the IVS5 + 1G>C substitution. The peroxisomal defect was later confirmed biochemically using cultured amniocytes, which were found to have elevated levels of very long chain fatty acids (VLCFA). This is the first report of prenatal diagnosis of D-bifunctional protein deficiency using molecular analysis of genomic DNA.

17-Hydroxysteroid Dehydrogenases↗
PubMed1995

The phosphodiesterase secreted by prestalk cells is necessary for Dictyostelium morphogenesis.

Dictyostelium discoideum secretes a cyclic nucleotide phosphodiesterase to control cAMP levels during development. Three promoters control expression of the gene--one during vegetative growth, one during aggregation, and one which constrains phosphodiesterase synthesis to prestalk cells. In this report we show that the expression of phosphodiesterase (PDE) in prestalk cells is necessary for morphogenesis. A gene that codes for a specific glycoprotein inhibitor of the phosphodiesterase (Kd = 0.1 nM) was fused to the prestalk-specific promoter of the PDE gene. Transformants carrying multiple copies of this construct secreted inhibitor in 100-fold excess after the aggregation process had occurred. The first effect seen was an elongated tip, followed by a block in slug formation and an inability to culminate. Stalk and spores cells are produced but morphogenesis is uncoupled from cellular differentiation. Overproduction of inhibitor during earlier stages delayed aggregation, but did not affect fruiting body formation. A phosphodiesterase mutant was transformed with a plasmid that expresses PDE only during aggregation and not in prestalk cells. The defect in aggregation was rescued, but the defect in later development was not. The combined results indicate that PDE expression in prestalk cells is critical to morphogenesis. To ask whether the inhibitor gene under its normal regulation had a role in aggregation or later morphogenesis, it was destroyed by homologous recombination. The loss of the gene did not prevent development under the conditions used.

Amino Acid Sequence↗
PubMedDate not supplied

Optic neuropathy from thiamine deficiency in a patient with ulcerative colitis.

A 35-year-old man with ulcerative colitis who was receiving parenteral feeding with large amounts of glucose, suddenly developed severe optic neuropathy and oculomotor palsy. The visual acuity fell bilaterally to 0. Although it was stated that thiamine has been regularly supplemented in the preceding period, high doses of vitamin B1 were given. Visual acuity promptly returned to 1.0 but large visual field defects persisted. Later on it appeared that erroneously no vitamin B1 has been given before.

Adult↗