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At least 1,261 records · Page 70Linked to original sources
PubMed2006

Recurrent ectopic calcification involving the maxillofacial skeleton: A potential harbinger of Albright's osteodystrophy.

We present a case of osteoma cutis as the initial presenting sign of Albright's osteodystrophy. Albright's osteodystrophy represents a challenge in both diagnosis and treatment because the phenotype manifests as a broad spectrum of biochemical and physical findings. The syndrome may be overlooked, particularly in the early phases when serum calcium and phosphorous levels may be normal. Although surgery is the treatment of osteoma cutis, recurrence is common, creating frustration for the patient's family and the surgeon. In the present case, a girl 4 months and 2 years of age presented with refractory ectopic calcification emanating from the maxilla and demonstrated repeated recurrence after surgical resection. This ectopic calcification was not adequately controlled until Albright's osteodystrophy was properly diagnosed and treated. A differential diagnosis and surgical approach to deal with recurrent ectopic calcification of the facial skeleton is outlined.

Cheek↗
PubMedDate not supplied

The use of ultrasound in the diagnosis of atypical pathology in the unossified skeleton.

Three cases are presented: a congenital dislocation of the patella, a congenital dislocation of the radial head, and an epiphysiolysis of the distal humerus. In all three cases the pathology involved unossified parts of the skeleton poorly demonstrated by plain radiographs. Ultrasonography proved useful in diagnosis and treatment of these cases.

Bone Diseases, Developmental↗
PubMed1995

Transgenic mice with targeted inactivation of the Col2 alpha 1 gene for collagen II develop a skeleton with membranous and periosteal bone but no endochondral bone.

Homologous recombination in embryonic stem cells was used to prepare transgenic mice with an inactivated Col2a1 gene for collagen II, the major protein component of the extracellular matrix of cartilage. Heterozygous mice had a minimal phenotype. Homozygous mice developed into fetuses that were delivered vaginally but died either just before or shortly after birth. The cartilage in the mice consisted of highly disorganized chondrocytes with a complete lack of extracellular fibrils discernible by electron microscopy. There was no endochondrial bone or epiphyseal growth plate in long bones. However, many skeletal structures such as the cranium and ribs were normally developed and mineralized. The results demonstrate that a well-organized cartilage matrix is required as a primary tissue for development of some components of the vertebrate skeleton, but it is not essential for others.

Animals↗
PubMed1975

Influence of Temperature on the Flowering of Lemna perpusilla 6746 Grown under Skeleton Photoperiods.

The flowering of Lemna perpusilla Torr. strain 6746 grown under 24-hour skeleton photoperiods consisting of 13- and 10.5-hour dark periods separated by 0.25-hr light pulses is strongly dependent on temperature. When plants are cultured in 50-ml Erlenmeyer flasks containing 20 ml of half-strength Hutner's medium supplemented with 1% (w/v) sucrose maximum, per cent, flowering occurs at 23 C. At temperatures above and below 23 C a marked decline in per cent flowering is seen.

Journal Article↗
PubMed2000

Gray-scale skeletonization of small vessels in magnetic resonance angiography.

Interpretation of magnetic resonance angiography (MRA) is problematic due to complexities of vascular shape and to artifacts such as the partial volume effect. We present new methods to assist in the interpretation of MRA. These include methods for detection of vessel paths and for determination of branching patterns of vascular trees. They are based on the ordered region growing (ORG) algorithm that represents the image as an acyclic graph, which can be reduced to a skeleton by specifying vessel endpoints or by a pruning process. Ambiguities in the vessel branching due to vessel overlap are effectively resolved by heuristic methods that incorporate a priori knowledge of bifurcation spacing. Vessel paths are detected at interactive speeds on a 500-MHz processor using vessel endpoints. These methods apply best to smaller vessels where the image intensity peaks at the center of the lumen which, for the abdominal MRA, includes vessels whose diameter is less than 1 cm.

Algorithms↗
PubMed2002

Spiral-CT-based assessment of tracheal stenoses using 3-D-skeletonization.

PURPOSE: Demonstration of a technique for three-dimensional (3-D) assessment of tracheal-stenoses, regarding site, length and degree, based on spiral computed tomography (S-CT). PATIENTS AND METHODS: S-CT scanning and automated segmentation of the laryngo-tracheal tract (LTT) was followed by the extraction of the LTT medial axis using a skeletonization algorithm. Orthogonal to the medial axis the LTT 3-D cross-sectional profile was computed and presented as line charts, where degree and length was obtained. Values for both parameters were compared between 36 patients and 18 normal controls separately. Accuracy and precision was derived from 17 phantom studies. RESULTS: Average degree and length of tracheal stenoses was found to be 60.5% and 4.32 cm in patients compared with minor caliber changes of 8.8% and 2.31 cm in normal controls (p << 0.0001). For the phantoms an excellent correlation between the true and computed 3-D cross-sectional profile was found (p << 0.005) and an accuracy for length and degree measurements of 2.14 mm and 2.53% respectively could be determined. The corresponding figures for the precision were found to be 0.92 mm and 2.56%. CONCLUSION: LTT 3-D cross-sectional profiles permit objective, accurate and precise assessment of LTT caliber changes. Minor LTT caliber changes can be observed even in normals and, in case of an otherwise normal S-CT study, can be regarded as artifacts.

Adolescent↗
PubMed1977

Macrophage dependency of T-lymphocyte mitogenesis by Nocardia rubra cell-wall skeleton.

The mitogenic activity of the cell-wall skeleton (CWS) of Nocardia rubra on purified splenic T-cells (thymus-derived lymphocytes) was investigated. N. rubra CWS showed remarkable mitogenic activity on normal spleen cells of C57BL/6J mice at concentrations ranging from 10 to 100 microgram per milliliter of culture medium, while, on purified splenic T-cells, N. rubra CWS did not act as an mitogen at any concentration. However, mitogenic activity of N. rubra CWS on T-cells was restored if purified splenic T-cells was reconstituted with X-irradiated peritoneal exudate cells (macrophages). The above results suggest the necessity of macrophages for T-lymphocyte activation by N. rubra CWS as well as PHA-P or Con A.

Animals↗
PubMed1983

The microvascular cast as a three-dimensional tissue skeleton: visualization of rapid morphological changes in tissues of the rat uterus.

A new interpretation of microvascular corrosion casting is described using examples from casts of the rat uterus taken during the oestrous cycle and early pregnancy. The casts are considered as representing a three-dimensional model of the tissue vascular space; this characteristic model or tissue skeleton is used to demonstrate transient morphological changes that may be difficult to visualize by other techniques, that may be obscured by other structures, or destroyed by conventional aldehyde fixation procedures. This new application, when supplemented by conventional histology to determine vessel distribution within the tissue and to confirm observations first made by casting, provides a technique for visualizing three-dimensional morphological changes in tissues that is accurate, relatively simple and far more rapid than the laborious method of histological serial sectioning and three-dimensional tissue reconstruction.

Animals↗
PubMed1996

The relationship between maximal jaw opening and size of skeleton: a cephalometric study.

The purpose of this study was to investigate the correlation between maximal mouth opening and size of the skeleton. The subjects were dental students at the Dental School of the Health Sciences University of Hokkaido with no functional disorders of the masticatory system. The stature and maximal mouth opening were recorded in 29 males and 31 females. These subjects agreed to have a lateral cephalogram taken at the closed and maximal mouth opening positions. The correlations between the maximal mouth opening and the body height, mandibular length and mandibular angle were significant. The correlation between the maximal mouth opening and the movement of the condyle was also significant.

Adult↗
PubMed1990

Vinculin is a permanent component of the membrane skeleton and is incorporated into the (re)organising cytoskeleton upon platelet activation.

Vinculin, a 130-kDa protein discovered in chicken gizzard smooth-muscle cells and subsequently also described in platelets, is believed to be involved in membrane-cytoskeleton interactions. In this study we investigated vinculin distribution in human blood platelets. Two skeletal fractions and a remaining cytosolic fraction were prepared with a recently described Triton X-100 lysis buffer causing minimal post-lysis breakdown by proteolysis. The presence of vinculin was demonstrated in the membrane skeleton and cytosol of resting and thrombin-activated human platelets. Upon thrombin stimulation vinculin also appeared in the cytoskeleton. this cytoskeletal incorporation was completed during the early stages of platelet aggregation and secretion, when the uptake of myosin, actin-binding protein and talin was still not maximal. We conclude therefore, that vinculin may play an important role in the structural (re)organisation of the human platelet cytoskeleton upon platelet activation.

Blood Platelets↗
PubMed1989

Osteomorphological features of the appendicular skeleton of gazelles, genus Gazella Blainville 1816, bohor reedbuck, Redunca redunca (Pallas, 1767) and bushbuck, Tragelaphus scriptus (Pallas, 1766).

Examined the osteomorphological features of the appendicular skeleton of Grant's gazelle (Gazella granti), bohor reedbuck (Redunca redunca) and bushbuck (Tragelaphus scriptus). Osseous remains of these medium sized antelopes are often encountered in African late Quaternary archaeological sites, but their specific identification poses considerable problems to the archaeozoologist. A key has been developed to meet this recurrent problem and a number of diagnostic osteomorphological features, allowing a distinction between the bovids mentioned, are established. The osteomorphological characteristics, typical for Grant's gazelle have also been observed in the eight other extant African gazelles and in two Asian species, the goitred gazelle (Gazella subgutterosa) and the mountain gazelle (Gazella gazella).

Animals↗
PubMed1990

In vitro activation of bovine macrophage and peripheral blood mononuclear cells by Nocardia rubra cell wall skeleton (N-CWS).

Nocardia rubra cell wall skeleton (N-CWS) was used for immunotherapy to bovine leukemia virus (BLV)-positive cattle with enlarged subcutaneous lymphatic nodules. Electron microscopical observations showed the infiltration of macrophage and T cells around N-CWS treated lesions. Antitumor effect induced by N-CWS was examined in vitro. The maximum cytolytic activity of macrophage was observed, when the cells were incubated with 10 micrograms/ml of N-CWS. Chemiluminescence response of peripheral blood mononuclear cells (PBMC) using N-CWS as stimulant was observed with a high level of activity for a long period, 5 hr. Mitogenic effect of N-CWS to PBMC was observed in the presence of macrophages but not without macrophages. Furthermore, interleukin 2 activity was recognized in supernatant of PBMC cultured with N-CWS. Maximum cytotoxic T lymphocyte response was induced when PBMC were cultured with 0.1 micrograms/ml of N-CWS.

Animals↗
PubMed1985

The fibrous skeleton of the corpora cavernosa and its probable function in the mechanism of erection.

The corpora cavernosa contain a fibrous skeleton composed of tunica albuginea with its fibrous columns, periarterial and perineural fibrous sheaths, and an intraparenchymal fibrous framework attached to all fibrous elements of the corpora cavernosa. This anatomical arrangement probably plays an important part in the firmness of the corpora cavernosa during erection. The fibrous framework, due to its numerous attachments to the deep surface of the tunica albuginea and its columns, when stretched during erection, prevents bending and deformation of the corpora cavernosa.

Adolescent↗
PubMed1994

The dose-response of percutaneous oestradiol implants on the skeletons of postmenopausal women.

OBJECTIVE: To determine whether there is a dose-response effect of percutaneous oestradiol implants on the skeletons of postmenopausal women using a range of doses available in clinical practice. DESIGN: One year randomised study. SUBJECTS: Forty-five postmenopausal women who requested oestrogen replacement therapy were randomised to receive 25 mg, 50 mg, or 75 mg oestradiol implants. The bone mineral density changes were compared with a control group of 15 untreated women. MAIN OUTCOME MEASURES: Dual energy X-ray absorptiometry using Hologic 1000 QDR before treatment and after one year of treatment. Plasma oestradiol and follicle stimulating hormone levels before treatment and after one year. RESULTS: There were significant correlations between the plasma oestradiol levels and the percentage increase in bone density at the lumbar spine, the total hip, the femoral neck, and the trochanter. The median (range) plasma oestradiol level was 327 pmol/l (114-853) in the 25 mg group, 358 pmol/l (220-957) in the 50 mg group and 518 pmol/l (167-828) in the 75 mg group. Three women who lost a significant amount of bone from the clinically relevant sites in the 25 mg oestradiol group all had plasma oestradiol levels below 300 pmol/l. None of the women in either the 50 mg or 75 mg oestradiol groups lost bone from these sites. CONCLUSIONS: Oestradiol implants resulted in a wide range of circulating oestradiol levels with each of the doses used. There was a significant relation between plasma oestradiol levels and the increases in bone density at both the lumbar spine and the proximal femur. None of the women lost bone density at the clinically important sites of the spine and femoral neck if their plasma oestradiol levels were above 300 pmol/l.

Absorptiometry, Photon↗
PubMedDate not supplied

Molecular evolution of fibrillar collagen in chordates, with implications for the evolution of vertebrate skeletons and chordate phylogeny.

Vertebrates have seven types of fibrillar collagens that are encoded by 11 genes. Types I, V, and XXIV collagens are components of mineralized bone, whereas types II, XI, and XXVII collagens are components of cartilage. In this study, we traced the molecular evolutionary history of chordate collagen genes and examined how gene duplications gave rise to the collagen genes used for skeletons. Our analyses of deuterostome collagen genes, including one amphioxus gene that we identified in this study, suggest that the common ancestors of deuterostomes possessed three fibrillar collagen genes. Expression analyses of chordate fibrillar collagen genes suggest that in the ancestors of chordates, fibrillar collagen was co-opted to the formation of the notochord sheath independently in three clades. Our results also imply that co-option of collagen genes to cartilage occurred in clade A (col2A1), clade B (col11A1, 11A2), and clade C (COL27A1). Similarly, some fibrillar collagen genes have been co-opted for mineralized bone independently from clade A genes (col1A1, 1A2, 5A2), clade B genes (col5A1), and clade C genes (COL24A1). These frequent co-options for notochord, cartilage, and mineralized bone must have been accompanied by the rapid evolution of cis-regulatory elements for transcription. In addition, we found that one of the ascidian fibrillar collagen genes possesses an amino acid insertion at the identical site of the C-terminal noncollagenous domain in vertebrate fibrillar collagen genes. This observation raises a suspicion about the relatively well-accepted phylogeny of the close relationship between amphioxus and vertebrates.

Amino Acid Sequence↗
PubMedDate not supplied

Monoclonal antibodies reveal complex structure in the membrane skeleton of Tetrahymena.

Twelve monoclonal antibodies were raised that are specific for the membrane skeleton of Tetrahymena. Five were directed against T. pyriformis and seven were directed against T. thermophila. Some cross-reactivity between species was found. Each monoclonal antibody recognized one of the three major components of epiplasm, i.e. the bands A, B, and C identified in electrophoretic separations of epiplasmic proteins. It was found, using these antibodies, that the epiplasmic proteins A, B and C have overlapping but independent distributions within the cell.

Animals↗
PubMed1986

Trace metals and degenerative diseases of the skeleton.

Aluminum related osteodystrophy is the most important manifestation of trace metal toxicity related to degenerative diseases of the skeleton. Aluminum overload occurs in chronic renal failure patients on hemodialysis treatment and results from transfer from dialysis solutions and from oral intake of aluminum containing phosphate binding gels. Laboratory diagnosis involves serum and bone analysis and bone staining for aluminum. A challenge test with desferrioxamine also aids in the diagnosis. Electrothermal atomic absorption spectrometry is widely used for aluminum detection. Guidelines for toxic concentrations of aluminum have been established.

Aluminum↗