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At least 811 records · Page 45Linked to original sources
PubMed2004

Idiopathic spinal cord herniation: a new theory of pathogenesis.

BACKGROUND: Idiopathic spinal cord herniation is a rare entity that has been described more frequently over the past few years. Its pathophysiology remains obscure, however. METHODS: We report a case of spinal cord herniation and review the literature extensively. In view of our review, we try to determine the clinical features of the condition and the diagnostic measures used, with emphasis on the role of magnetic resonance (MR) phase-contrast CSF study. The factors affecting the outcome of the condition are also studied including time and type of presentation, as well as the surgical procedure performed. The pathophysiological mechanisms behind spontaneous herniation are discussed, and a new hypothesis is proposed. RESULTS: Idiopathic spinal cord herniation occurs in the middle-aged adult, with a preponderance of patients being female. Brown-Séquard syndrome is the most common clinical presentation and usually progresses to spastic paraparesis. MRI typically shows a ventral kink in the thoracic cord, with MR phase-contrast imaging proving an important addition to exclude an arachnoid cyst. Better outcomes were noted in the patients treated earlier, and in those with no spasticity. Widening the dural defect seems to afford better results compared to grafting of the defect. The prognosis is favorable after correction, though a vertebral body herniation variant may be associated with worse outcome. In view of the chronology of events and imaging studies in our patient, we hypothesize that herniation occurs as an acquired phenomenon where an inflammatory process results in adherence between the spinal cord and the dura, with erosion, formation of a dural defect, and then later herniation occurring with cerebral spinal fluid (CSF) pulsations. CONCLUSIONS: Idiopathic herniation of the spinal cord should be recognized and treated early to reach a favorable outcome. It seems to be an acquired condition likely caused by an inflammatory event, the nature of which is to be determined.

Adult↗
PubMed2005

tortuga refines Notch pathway gene expression in the zebrafish presomitic mesoderm at the post-transcriptional level.

We have identified the zebrafish tortuga (tor) gene by an ENU-induced mutation that disrupts the presomitic mesoderm (PSM) expression of Notch pathway genes. In tor mutants, Notch pathway gene expression persists in regions of the PSM where expression is normally off in wild type embryos. The expression of hairy/Enhancer of split-related 1 (her1) is affected first, followed by the delta genes deltaC and deltaD, and finally, by another hairy/Enhancer of split-related gene, her7. In situ hybridization with intron-specific probes for her1 and deltaC indicates that transcriptional bursts of expression are normal in tor mutants, suggesting that tor normally functions to refine her1 and deltaC message levels downstream of transcription. Despite the striking defects in Notch pathway gene expression, somite boundaries form normally in tor mutant embryos, although somitic mesoderm defects are apparent later, when cells mature to form muscle fibers. Thus, while the function of Notch pathway genes is required for proper somite formation, the tor mutant phenotype suggests that precise oscillations of Notch pathway transcripts are not essential for establishing segmental pattern in the presomitic mesoderm.

Animals↗
PubMed1998

Hydration of polyethylene glycol-grafted liposomes.

This study aimed to characterize the effect of polyethylene glycol of 2000 molecular weight (PEG2000) attached to a dialkylphosphatidic acid (dihexadecylphosphatidyl (DHP)-PEG2000) on the hydration and thermodynamic stability of lipid assemblies. Differential scanning calorimetry, densitometry, and ultrasound velocity and absorption measurements were used for thermodynamic and hydrational characterization. Using a differential scanning calorimetry technique we showed that each molecule of PEG2000 binds 136 +/- 4 molecules of water. For PEG2000 covalently attached to the lipid molecules organized in micelles, the water binding increases to 210 +/- 6 water molecules. This demonstrates that the two different structural configurations of the PEG2000, a random coil in the case of the free PEG and a brush in the case of DHP-PEG2000 micelles, differ in their hydration level. Ultrasound absorption changes in liposomes reflect mainly the heterophase fluctuations and packing defects in the lipid bilayer. The PEG-induced excess ultrasound absorption of the lipid bilayer at 7.7 MHz for PEG-lipid concentrations over 5 mol % indicates the increase in the relaxation time of the headgroup rotation due to PEG-PEG interactions. The adiabatic compressibility (calculated from ultrasound velocity and density) of the lipid bilayer of the liposome increases monotonically with PEG-lipid concentration up to approximately 7 mol %, reflecting release of water from the lipid headgroup region. Elimination of this water, induced by grafted PEG, leads to a decrease in bilayer defects and enhanced lateral packing of the phospholipid acyl chains. We assume that the dehydration of the lipid headgroup region in conjunction with the increase of the hydration of the outer layer by grafting PEG in brush configuration are responsible for increasing thermodynamic stability of the liposomes at 5-7 mol % of PEG-lipid. At higher PEG-lipid concentrations, compressibility and partial volume of the lipid phase of the samples decrease. This reflects the increase in hydration of the lipid headgroup region (up to five additional water molecules per lipid molecule for 12 mol % PEG-lipid) and the weakening of the bilayer packing due to the lateral repulsion of PEG chains.

Calorimetry, Differential Scanning↗
PubMed2003

The Caenorhabditis elegans innexin INX-3 is localized to gap junctions and is essential for embryonic development.

Innexins are the proposed structural components of gap junctions in invertebrates. Antibodies that specifically recognize the Caenorhabditis elegans innexin protein INX-3 were generated and used to examine the patterns of inx-3 gene expression and the subcellular sites of INX-3 localization. INX-3 is first detected in two-cell embryos, concentrated at the intercellular interface, and is expressed ubiquitously throughout the cellular proliferation phase of embryogenesis. During embryonic morphogenesis, INX-3 expression becomes more restricted. Postembryonically, INX-3 is expressed transiently in several cell types, while expression in the posterior pharynx persists throughout development. Through immuno-EM techniques, INX-3 was observed at gap junctions in the adult pharynx, providing supporting evidence that innexins are components of gap junctions. An inx-3 mutant was isolated through a combined genetic and immunocytochemical screen. Homozygous inx-3 mutants exhibit defects during embryonic morphogenesis. At the comma stage of early morphogenesis, variable numbers of cells are lost from the anterior of inx-3(lw68) mutants. A range of terminal defects is seen later in embryogenesis, including localized rupture of the hypodermis, failure of the midbody to elongate properly, abnormal contacts between hypodermal cells, and failure of the pharynx to attach to the anterior of the animal.

Animals↗
PubMed1989

Flexible, actively deflectable fiberoptic ureteronephroscopy.

We performed 76 flexible, actively deflectable ureteronephroscopic procedures in 68 patients. Of the patients 61 were examined transurethrally, 3 via an ileal loop, 2 percutaneously and 2 via ureterostomy. Indications for flexible, actively deflectable ureteronephroscopy included urolithiasis in 28 patients, upper tract filling defect in 25, lateralizing hematuria in 8, retrograde endopyelotomy in 2, post-endopyelotomy evaluation in 6, surveillance for transitional cell carcinoma in 4 and other reasons in 3. The area of interest was accessed successfully in 96% of the patients. In 57 instances an attempt was made to inspect all calices and was successful in two-thirds of the patients. However, greater than 75% of the collecting system was accessed in all but 2 of these 57 patients. Over-all, diagnostic and/or therapeutic maneuvers were successful in 84% of the patients. Flexible, actively deflectable ureteronephroscopy provides the urologist with a minimally invasive means to evaluate and treat pathological conditions of the upper urinary tract.

Adolescent↗
PubMed1975

Spontaneous remission of peripelvic renal cysts.

Three cases are presented of spontaneous regression of peripelvic renal cysts. The lesions were manifested by lateral extrinsic pressure defects in the renal pelvis and major calices (all 3 cases), and selective renal angiography showing stretching of vessels plus sharply defined defects in the nephrographic phase (2 patients). In 1 case the mass disappeared following trauma to the flank, while in the remaining 2 cases it disappeared spontaneously.

Adult↗
PubMed1990

An in vitro comparison of the sealing ability of materials placed in lateral root perforations.

The in vitro sealing ability of Tytin amalgam, Ketac-Silver, and Prisma VLC Dycal was compared. Roots of extracted teeth were perforated laterally. After the defects were repaired, the teeth were immersed in dye for 10 days and then sectioned, and the linear extent of dye penetration was measured. Statistical analysis showed that the Prisma VLC Dycal group exhibited significantly less dye penetration than the other two groups (p less than 0.01). No difference was found between the Tytin and Ketac-Silver groups.

Calcium Hydroxide↗
PubMed2002

Transplantation of human limbal epithelium cultivated on amniotic membrane for the treatment of severe ocular surface disorders.

PURPOSE: To study the short-term clinical results of transplanting of cultivated corneal/limbal epithelial cells on human amniotic membrane (AM) for limbal deficiency. DESIGN: Noncomparative, retrospective interventional case series. PARTICIPANTS: Thirteen eyes of 13 patients with severe limbal deficiency (Stevens-Johnson syndrome in eight eyes, ocular cicatricial pemphigoid in three eyes, and chemical burns in two eyes) were treated at the department of Ophthalmology, Tokyo Dental College, Japan. INTERVENTION: Cultivated allo-limbal epithelium was transplanted onto the ocular surface of patients with severe limbal deficiency. MAIN OUTCOME MEASURES: Ocular surface reconstruction with corneal epithelialization, changes in visual acuity, and postoperative complications were studied. Histologic examinations were also performed on cultivated epithelium. RESULTS: Cultivated corneal epithelium on AM formed two to three layers with the formation of basement membrane-like structures. After the surgery, the epithelium regenerated and covered the ocular surface in eight eyes (61.5%). However, three of the eight eyes developed partial conjunctival invasion, and two eyes later developed epithelial defects. At last examination, corneal epithelialization was achieved in six eyes (46.2%). Five eyes had conjunctivalization, one eye had dermal epithelialization, and one eye was not epithelialized. Complications were corneal perforation in four eyes and infectious keratitis in two eyes. CONCLUSIONS: This study demonstrates that the success rate for transplanting cultivated allo-limbal epithelium on the AM is not different from the conventional limbal and AM transplantation for the treatment of severe limbal stem cell dysfunction.

Adolescent↗
PubMed1987

Morphometric study of cauliflower collagen fibrils in dermatosparaxis of the calves.

The abnormal cauliflower collagen fibrils present in the skin of dermatosparactic calves were studied by electron microscopy and computerized image analysis. The structure of the fibrils is heterogeneous and varies according to their location in the dermis. Cauliflower fibrils seems due to a defect in the lateral cohesion between the constitutive procollagen polymers. This is associated with the presence of a non-collageneous material larger than the aminopropeptide surrounding the procollagen polymers, while the volume occupied by procollagen in each fibril is comparable to that of collagen in normal fibrils.

Animals↗
PubMed1992

Freeze-thawed skeletal muscle autografts used for brachial plexus repair in the non-human primate.

An experimental study undertaken in the marmoset is reported. A defect in the lateral cord of the brachial plexus was repaired with a longitudinally aligned freeze-thawed skeletal muscle autograft. Recovery was assessed after one year using sensory and motor electrophysiological and also histological examination of the nerve. The results show that this is a satisfactory method of peripheral nerve repair in the marmoset. It is suggested that the technique may be applicable to repair of the human brachial plexus.

Animals↗
PubMed1984

Osteoplastic surgery of the sinus maxillaris--the "bone lid"-method.

During osteoplastic surgery of the maxillary sinus the surgical defect in the lateral wall of the maxillary sinus is re-closed by means of free reimplantation of the "bone lid", which had been temporarily removed together with the integral mucosa, during creation of the access. This "bone lid"-method has so far been employed successfully in approx. 600 cases. For covering the basal area of the bone lesion of the drainage window to the lower nasal passage, created during surgery by means of a flap of mucosa and periosteum, a novel type of tamponade using an inflatable balloon was tested. The following pages report on the surgical techniques employed and on systematic follow-up investigations.

Drainage↗
PubMed2001

Hypothalamic regulation of sleep.

The recent discovery linking narcolepsy, a sleep disorder characterized by very short REM sleep latency, with a neuropeptide that regulates feeding and energy metabolism, provides a way to understand how several behaviors may be disrupted as a result of a defect in this peptide. In this chapter we review the evidence linking hypocretin and sleep, including our own studies, and propose that a defect in the lateral hypothalamus that also involves the hypocretin neurons is likely to produce a disturbance in sleep, mood, appetite, and rhythms.

Animals↗
PubMedDate not supplied

Preliminary study of cardiac accumulation of F-18 fluorotamoxifen in patients with breast cancer.

The clinical meaning of cardiac uptake of [18F]fluorotamoxifen was assessed. Tamoxifen, a nonsteroidal antiestrogenic drug for treatment and prevention of breast cancer, has a cardioprotective, estrogen-like effect in postmenopausal women. We conducted a pilot study of [18F]fluorotamoxifen to evaluate its clinical usefulness in patients with breast cancer. Significant cardiac uptake of [18F]fluorotamoxifen in five patients was found in the pilot study. We performed positron emission tomography (PET) with [18F]fluorotamoxifen. The intracardiac distribution of [18F]fluorotamoxifen was observed and compared with the patients' clinical symptoms, past history, and results of the electrocardiogram (ECG). None of the patients had a prior history of ischemic heart disease. Various patterns of [18F]fluorotamoxifen distribution were seen in the heart: one patient showed homogeneous distribution; two had defects in the lateral wall; one had patchy distribution; and in one the uptake was questionable. Non-uniform cardiac uptake may be related to myocardial damage. Cardiac uptake of tamoxifen suggests that its cardioprotective benefits may be related not only to serum cholesterol reduction but also to a direct cardioprotective action. Further experimental studies are required to elucidate the pathophysiological mechanism of cardiac uptake of [18F]fluorotamoxifen.

Adult↗
PubMed2000

The zebrafish forkhead transcription factor FoxH1/Fast1 is a modulator of nodal signaling required for organizer formation.

BACKGROUND: Signaling molecules related to the Nodal protein play essential roles in the formation and patterning of the gastrula organizer and the germ layers during vertebrate development. The forkhead transcription factor FoxH1 (also known as Fast1) is a component of the Nodal signaling pathway. Although different roles have been suggested for FoxH1, its specific function during development is still unclear. RESULTS: We report that the zebrafish locus schmalspur (sur) encodes a member of the FoxH1 family. Maternal sur transcripts were localized to the animal pole during oogenesis. Further expression was detected in a dorsoventral gradient at the onset of gastrulation and in specific domains in the organizer, notochord and lateral plate mesoderm. Embryos lacking zygotic sur function had variable deficiencies of prechordal plate and ventral neuroectoderm. In the absence of both maternal and zygotic sur function, embryos failed to form a morphologically distinct gastrula organizer and, later, developed severe defects in all axial structures. In these embryos, expression of nodal genes was initiated but not maintained. Unlike embryos lacking Nodal signaling, sur mutants formed endoderm and paraxial mesoderm. CONCLUSIONS: FoxH1 is involved in regulatory feedback loops that control the duration and intensity of Nodal signals in early patterning. In zebrafish, FoxH1 is not essential to induce Nodal-dependent cell fates, but its function is central in modulating and enhancing morphogenetic Nodal signals.

Amino Acid Sequence↗
PubMed2000

Dental erosion in Cuban children associated with excessive consumption of oranges.

Marked erosion at the mesial edges of upper front teeth was observed during an examination of Cuban children. The preferential erosion of mesial edges produced characteristic V-shaped defects on upper central incisors, and the aim of the present study, carried out on 12-yr-old children (N = 1010) in 10 communities in the Province of Havana was to establish the frequency of dental erosion and explain its occurrence. The symmetrical erosion of teeth 11 and 21 (excluding crown injuries and attrition) were clinically classified into four grades: 0.5 = objectionable; 1 = abnormal mesial shortening of incisal edges; 2 = V-shaped defect of cutting edges; 3 = exposure of dentine and extension of the erosive defect to the lateral incisors. In four of the communities, children did not show or rarely showed incisal erosion. In the other six communities, the frequency was surprisingly high (16.6-40.9%). Overall, 17.4% of children exhibited erosion, and the occurrence was significantly higher in girls (20.7%) than in boys (15.0%). The typical V-shaped pattern of erosion seems to be a consequence of the manner in which citrus fruits are eaten. There was also a positive correlation between the frequency of dental erosion and the proximity of citrus plantations, which presumably related to the extent of (daily) orange consumption.

Adolescent↗
PubMedDate not supplied

FISH studies in 45 patients with Rubinstein-Taybi syndrome: deletions associated with polysplenia, hypoplastic left heart and death in infancy.

Rubinstein-Taybi syndrome (RTS) is a dominant Mendelian disorder characterised by mental retardation, a typical facies, broad thumbs and short stature. Previous reports indicated that 4-25% of RTS patients have a submicroscopic 16p13.3 deletion of the CBP gene. Using FISH and cosmid probes RT100, RT191 and RT203 we studied 45 RTS patients from Germany, the Czech Republic, Austria and Turkey and found four deletions (8.9%, pooled data including other studies: 11%). All deletions were interstitial; three spanned the CBP gene (RT100-RT203) and one was smaller (RT100 only). Previous studies reported no phenotype-genotype correlation between RTS patients with or without a deletion. Our findings suggest a more severe phenotype. The mean age at presentation was 0.96 years in patients with a deletion as against 11.12 years in those without. Patients A and B with a deletion died in infancy which is rare in RTS and was not observed among the other patients. Patients A and D had accessory spleens, Patient A with hypoplastic left heart, abnormal pulmonary lobulation and renal agenesis. This is the second report of hypoplastic left heart and the first report of polysplenia with RTS. The signs suggest a developmental field defect (disturbance of laterality) either as a newly recognised pattern of RTS, or alternatively a novel contiguous gene syndrome.

Adolescent↗
PubMed2002

Tolerance of glycosylphosphatidylinositol (GPI)-specific phospholipase D overexpression by Chinese hamster ovary cell mutants with aberrant GPI biosynthesis.

Mammalian glycosylphosphatidylinositol (GPI)-specific phospholipase D (GPI-PLD) is capable of releasing GPI-anchored proteins by cleavage of the GPI moiety. A previous study indicated that overexpression of GPI-PLD in mouse RAW 264.7 monocytes/macrophages could be cytotoxic, since survivors of stable transfections had enzymic activity no higher than untransfected cells [Du and Low (2001) Infect. Immun. 69, 3214-3223]. We investigated this phenomenon by transfecting bovine GPI-PLD cDNA stably into Chinese hamster ovary (CHO) cells using a bi-cistronic expression system. The surviving transfectants showed an unchanged cellular level of GPI-PLD, supporting the cytotoxicity hypothesis. However, when using a CHO mutant defective in the second step of GPI biosynthesis as host, the expression level of GPI-PLD in stable transfectants was increased by 2.5-fold compared with untransfected or empty-vector-transfected cells. To identify the mechanism, we studied another CHO cell mutant (G9PLAP.D5), which seems to be defective at a later stage in GPI biosynthesis. In sharp contrast with wild-type cells, GPI-PLD activity in G9PLAP.D5 transfected with bovine GPI-PLD cDNA was 100-fold higher than untransfected or empty-vector-transfected cells. This was accompanied by a significant release of alkaline phosphatase into the medium and a decrease in membrane-associated alkaline phosphatase. Taken together, our results indicate that overexpression of GPI-PLD is lethal to wild-type cells, possibly by catalysing the overproduction of GPI-derived toxic substances. We propose that cells with abnormal GPI biosynthesis/processing can escape the toxic effect of these substances.

Animals↗