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At least 595 records · Page 33Linked to original sources

PubMed1976

[Sarcoidosis of the skeleton. Review of the literature and case report. (author's transl)].

The frequency of sarcoidosis in the skeleton varies between 3 and 36%. Skeletal sarcoidosis is rare in early stages (Löfgren-syndrom), relatively frequent in late stages. The initial phase is characterized by the formation of miliary non-caseating epitheloid-cell granulomas in the bone marrow. The invasion of the bone marrow may either be tolerated by the bone tissue or it initiates a perifocal osteosclerosis or a osteolysis. Correspondingly the X-ray of the skeleton shows normal structure or focal osteosclerosis or osteolysis. Therefore in the first case the sarcoidosis cannot be identified by X-ray. Most frequent locations are the phalanges of the fingers and toes, less common the stem skelton (skull, vertebrae, pelvis) and very rare the long tubular bones. In most cases the skeletal sarcoidosis is well tolerated. Report of a case of osteosclerotic sarcoidosis of the pelvis of a 39-years old woman with generalized sarcoidosis which was diagnozed four years earlier. The X-rays of the phalanges were normal. The biopsy of the iliac crest shows miliary sarcoid granuloma of the bone marrow and accretion of lamellar bone on the surface of the bone trabeculi with a distinct mosaic pattern. Treatment with steroids during the following five years was ineffective.

Adolescent↗

PubMed1979

[The importance of scintimetry in the differential diagnosis of roentgenological areas of increased "translucence" in the skeleton of children (author's transl)].

A random selection of lesions representing osteolytic bone processes was evaluated with the "region-of-interest" technique in order to determine whether scintimetry can be helpful in the differential diagnosis of such processes in children. Bone tumours with structural densification, as well as osteomyelitides, were reviewed for comparative purposes. It was found that scintigraphy of the skeleton, while supplying additional and clinically quite interesting information, does not make any substantial contribution to the differential diagnostic clarification of roentgenological translucence in the skeleton of children.

Bone Resorption↗

PubMed2002

[Studies on image quality, high contrast resolution and dose for the axial skeleton and limbs with a new, dedicated CT system (ISO-C-3 D)].

PURPOSE: Evaluation of 3D-CT imaging of the axial skeleton and different joints of the lower and upper extremities with a new dedicated CT system (ISO-C-3D) based on a mobile isocentric C-arm image amplifier. MATERIAL AND METHODS: 27 cadaveric specimes of different joints of the lower and upper extremities and of the spinal column were examined with 3D-CT imaging (ISO-C-3D). All images were evaluated by 3 radiologists for image quality using a semiquantitative score (score value 1: poor quality; score value 4: excellent quality). In addition, dose measurements and measurements of high contrast resolution were performed in comparison to conventional and low-dose spiral CT using a high contrast phantom (Catphan, Phantom Laboratories). RESULTS: Adequate image quality (mean score values 3 - 4) could be achieved with an applied dose comparable to low-dose CT in smaller joints such as wrist, elbow, ankle and knee. A remarkably inferior image quality resulted in imaging of the hip, lumbar and thoracic spine (mean score values 2 - 3) in spite of almost doubling the dose (dose increased by 85 percent). The image quality of shoulder examinations was insufficient (mean score value 1). Phantom studies showed a high-contrast resolution comparable to helical CT in the xy-axis (9 lp/cm). CONCLUSION: Preliminary results show, that image quality of C-arm-based CT-imaging (ISO-C-3D) seems to be adequate in smaller joints. ISO-C-3D images of the hip and axial skeleton show a decreased image quality, which does not seem to be sufficient for diagnosing subtle fractures.

Arm↗

PubMed1994

[CT-guided biopsies of the axial skeleton. The approaches and results].

The value of percutaneous CT-guided biopsies of the axial skeleton for establishing a diagnosis is determined from a series of 75 punctures in 74 patients in retrospect. Indications showed benign conditions to prevail over malignant lesions by a ratio of 1.6:1. Biopsy routes turned out to be strongly determined by regional anatomy allowing for a standardised procedure in each area. 64 out of 75 histological diagnoses were confirmed by open surgery (n = 17) or follow-up (n = 58) accounting for an accuracy of 85.3%. In 7 cases no definite diagnosis could be made from the sample and in 4 cases the diagnosis proved false although tissue cores could be obtained in each case. No serious or irreversible complications occurred. CT-guided punctures of the axial skeleton are considered a safe and highly accurate procedure to establish a definite diagnosis unless there is a primary indication for surgery or the need for decompression.

Adolescent↗

PubMed1992

[Ultrasonic velocity measurements at weight-bearing and non-weight-bearing sites of the peripheral skeleton. The effect of physical activity in soccer players].

Ultrasound transmission velocity at the appendicular skeleton is determined by elastic properties of the bone as mass density. We evaluated ultrasound transmission velocity at the os calcis of both feet and at the proximal phalanges of DII and DIII of both hands in 51 male subjects. 28 of them were professional soccer players of the 1st German division, 11 subjects performed non-professional exercise in various athletic organisations regularly and 12 did not exercise at all. A significant difference in the speed of sound could be seen at os calcis, where the soccer players had higher velocities than the other groups. The differences between the groups at the upper and lower extremities suggest that changes in ultrasound transmission velocity are not only affected by structural changes in the aging skeleton, as it might be suggested by age differences, but by exercise. Physical exercise can change the properties (structure and/or density) of weightbearing bone and this can be detected by measuring ultrasound velocity.

Adolescent↗

PubMedDate not supplied

[Changes in the juvenile pelvis in congenital systemic diseases of the skeleton (author's transl)].

Constitutional disorders of the skeleton show a characteristic appearance in the radiogram of the juvenile pelvis. These radiologic changes are presented in tables and are discussed demonstrating individual cases. Because of the limited reactive possibility of the skeleton not every disorder shows a typical feature of differential diagnosis and radiologic pattern. To differentiate from the congenital dysplasia of the hip and Legg-Calvé-Perthes disease the distribution of the skeletal disorders and their course therefore have to be known. Accordingly the therapeutic consequences have to be drawn. In this purpose the radiologic diagnostics of the juvenile pelvis are of significant value.

Bone Diseases, Developmental↗

PubMed1982

[Dynamic computer tomographic for tumours of the facial skeleton (author's transl)].

Serial computer tomography after intravenous bolus injection of contrast provides information concerning the vascularity of tumours in the facial skeleton. In addition the relationship of the tumour to the major vessels and their displacement or compression can be demonstrated. This provides information additional to the ordinary computer tomogram, so that neoplasms of the facial skeleton can be shown at various stages and their extent determined. A requirement for the use of serial CT is a scanner with a short scan time and scan interval.

Angiography↗

PubMed1981

[Radiological changes in the skeleton due to anticonvulsant therapy in childhood (author's transl)].

Anticonvulsant therapy can lead to severe rachitic changes in the skeleton which closely resemble renal osteopathy. In addition to apparent widening of the epiphyseal plate, there are changes in the cortex of the long bones. Within four to six weeks of the commencement of vitamin D therapy, recalcification of the poorly recognised. Since the changes are best seen in the hand, further examinations of the skeleton are only indicated if there are positive findings in the hand.

Adolescent↗

PubMed1994

[The effect of a low-dose hydrochlorothiazide therapy on the bone mineral content of the axial and peripheral skeleton].

An increase in bone mineral content (BMC) as well as a decrease in the incidence of fracture of the proximal femur have been described in patients on thiazide diuretic treatment. A study was undertaken to assess, by means of dual X-ray absorptiometry, the effect of chronic low-dosage antihypertensive treatment with hydrochlorothiazide (HCT; < or = 25 mg daily) on lumbar vertebrae (representing the axial skeleton) and the nondominant radius (peripheral skeleton). Measurements were made on 27 women (mean age 63.8 +/- 8.2 years) and 23 men (65.9 +/- 9.5 years) and compared with a control group of 19 women (62 +/- 8.7 years) and 20 men (65.9 +/- 9.5 years) with minor surgical or dermatological lesions who had never taken HCT or other drugs with potential effects on mineral bone metabolism. In men who had been on HCT for more than 5 years, BMC of the lumbar vertebrae was higher by 10.3% and of the radius by 3.8% than among the controls (differences not significant). In women who had been on HCT for more than 5 years, the corresponding increases were 19.6% (P < 0.05) and 5.4% (not significant). Among those patients who had been on HCT for less than 5 years there were no significant differences compared with the control group. There were no significant differences between the groups relating as regards the proximal radius which, in contrast to the ultradistal radius, consists predominantly of cortical bone. -These data indicate that, while HCT has only a slight influence on BMC, it can be considered to have a desirable associated effect in the antihypertensive treatment of elderly patients.

Absorptiometry, Photon↗

PubMed2002

Impaired neural tube closure, axial skeleton malformations, and tracheal ring disruption in TRAF4-deficient mice.

TRAF4 belongs to the tumor necrosis factor receptor-associated factor (TRAF) family of proteins but, unlike other family members, has not yet been clearly associated to any specific receptor or signaling pathway. To investigate the biological function of TRAF4, we have generated traf4-deficient mice by gene disruption. The traf4 gene mutation is embryonic lethal but with great individual variation, as approximately one third of the homozygous mutant embryos died in utero around embryonic day 14, whereas the others reach adulthood. Surviving mutant mice manifest numerous developmental abnormalities; notably, 100% of homozygous mutant mice suffer respiratory disorder and wheezing caused by tracheal ring disruption. Additional malformations concern mainly the axial skeleton, as the ribs, sternum, tail, and vertebral arches are affected, with various degrees of penetrance. Traf4-deficient mice also exhibit a high incidence of spina bifida, a defect likened to neural tube defects (NTD) that are common congenital malformations in humans. Altogether, our results demonstrate that TRAF4 is required during embryogenesis in key biological processes including the formation of the trachea, the development of the axial skeleton, and the closure of the neural tube. Considering the normal expression pattern of TRAF4 in neural tissues, we can conclude that TRAF4 participates in neurulation in vivo.

Animals↗

PubMed1975

Biosynthesis of delta-aminolevulinic acid from the intact carbon skeleton of glutamic acid in greening barley.

The customary route in animals and bacteria for delta-aminolevulinic acid biosynthesis is from glycine and succinyl CoA, catalyzed by the enzyme delta-aminolevulinic acid synthetase [succinyl-CoA:glycine C-succinyltransferase (decarboxylating), EC 2.3.1.37]. Attempts to demonstrate this route in plants have been unsuccessful. Evidence is given for a new enzymic route of synthesis of delta-aminolevulinic acid in plants. This route involves the incorporation of the intact five-carbon skeleton of glutamic acid into delta-aminolevulinic acid. Demonstration of the new pathway in plants has been made by feeding specifically labeled [14C]glutamic acid to etiolated barley shoots greening in the light. In the presence of levulinate, a competitive inhibitor of delta-aminolevulinic acid dehydrastase [porphobilinogen synthase; delta-aminolevulinate hydro-lyase (adding delta-aminolevulinate and cyclizing); EC 4.2.1.24], delta-aminolevulinate accumulates. The delta-aminolevulinate formed was chemically degraded by periodate to formaldehyde and succinic acid. The C5 (formaldehyde) fragment was separated, as the 5,5-dimethyl-1,3-cyclohexanedione (dimedone) derivative, from the C1-C4 (succinic acid) fragment. The C5 atom contained radioactivity predominantly derived from C1 of glutamic acid. Conversely, the labeled C3 and C4 atoms of glutamic acid were found primarily in the succinic acid (C1-C4) fragment of delta-aminolevulinate. This labeling pattern for delta-aminolevulinic acid is consistent with a biosynthetic route utilizing the intact five-carbon skeleton of alpha-ketoglutarate, glutamate, or glutamine, and is inconsistent with the delta-aminolevulinic acid synthetase pathway utilizing glycine and succinyl CoA as precursors.

Aminolevulinic Acid↗

PubMed1997

Na,K-ATPase transport from endoplasmic reticulum to Golgi requires the Golgi spectrin-ankyrin G119 skeleton in Madin Darby canine kidney cells.

Spectrin (betaISigma*) and ankyrin (AnkG119) associate with Golgi membranes and the dynactin complex, but their role in vesicle trafficking remains uncertain. We find that the actin-binding domain and membrane-association domain 1 (MAD1) of betaI spectrin together form a constitutive Golgi targeting signal in transfected MDCK cells. Expression of this signal in transfected cells disrupts the endogenous Golgi spectrin skeleton and blocks transport of alpha- and beta-Na,K-ATPase and vesicular stomatitis virus-G protein from the endoplasmic reticulum (ER) but does not disrupt the formation of Golgi stacks, the distribution of beta-COP, or the transport and surface display of E-cadherin. The Golgi spectrin skeleton is thus required for the transport of a subset of membrane proteins from the ER to the Golgi. We postulate that together with polyfunctional adapter proteins such as AnkG119, Golgi spectrin forms a docking complex that acts prior to the cis-Golgi, presumably with vesicular-tubular clusters (VTCs or ERGIC), to sequester specific membrane proteins into vesicles transiting between the ER and Golgi, and subsequently (probably involving other isoforms of spectrin and ankyrin) to mediate cargo transport within the Golgi and to other membrane compartments. We hypothesize that this vesicular spectrin-ankyrin adapter-protein trafficking (or tethering) system (SAATS) mediates the capture and transport of many membrane proteins and acts in conjunction with vesicle-targeting molecules to effect the efficient transport of cargo proteins.

Animals↗

PubMed1998

Biochemical analysis of potential sites for protein 4.1-mediated anchoring of the spectrin-actin skeleton to the erythrocyte membrane.

Erythrocyte protein 4.1 has been hypothesized to link the spectrin-actin junctional complex directly to the cytoplasmic domain of glycophorin C, but this bridging function has never been directly demonstrated. Because an alternative protein-mediated bridge between the junctional complex and the cytoplasmic domain of band 3 is also plausible, we have undertaken to characterize the membrane sites to which protein 4.1 can anchor the spectrin and actin skeleton. We demonstrate that proteolytic removal of the cytoplasmic domain of band 3 has minimal effect on the ability of protein 4.1 to promote 125I-labeled spectrin and actin binding to KI-stripped erythrocyte membrane vesicles. We also show that quantitative blockade of all band 3 sites with either monoclonal or polyclonal antibodies to band 3 is equally ineffective in preventing protein 4.1-mediated association of spectrin and actin with the membrane. In contrast, obstruction of protein 4.1 binding to its docking site on the cytoplasmic pole of glycophorin C is demonstrated to reduce the same protein 4.1 bridging function by approximately 85%. We conclude from these data that (i) glycophorin C contributes the primary anchoring site of the protein 4.1-mediated bridge to the spectrin-actin skeleton; (ii) band 3 is incapable of serving the same function; and (iii) additional minor protein 4.1 bridging sites may exist on the human erythrocyte membrane.

Actins↗

PubMed2001

The biosynthetic incorporation of the intact leucine skeleton into sterol by the trypanosomatid Leishmania mexicana.

The amino acid leucine is efficiently used by the trypanosomatid Leishmania mexicana for sterol biosynthesis. The incubation of [2-(13)C]leucine with L. mexicana promastigotes in the presence of ketoconazole gave 14alpha-methylergosta-8,24(24(1))-3beta-ol as the major sterol, which was shown by mass spectrometry to contain up to six atoms of (13)C per molecule. (13)C NMR analysis of the 14alpha-methylergosta-8,24(24(1))-3beta-ol revealed that it was labeled in only six positions: C-2, C-6, C-11, C-12, C-16, and C-23. This established that the leucine skeleton is incorporated intact into the isoprenoid pathway leading to sterol; it is not converted first to acetyl-CoA, as in animals and plants, with utilization of the acetyl-CoA to regenerate 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA). An inhibitor of HMG-CoA synthase (L-659,699) blocked the incorporation of [1-(14)C]acetate into sterol but had no inhibitory effect on [U-(14)C]leucine incorporation. The HMG-CoA reductase inhibitor lovastatin inhibited promastigote growth and [U-(14)C]leucine incorporation into sterol. The addition of unlabeled mevalonic acid (MVA) overcame the lovastatin inhibition of growth and also diluted the incorporation of [1-(14)C]leucine into sterol. These results are compatible with two routes by which the leucine skeleton may enter intact into the isoprenoid pathway. The catabolism of leucine could generate HMG-CoA that is then directly reduced to MVA for incorporation into sterol. Alternatively, a compound produced as an intermediate in leucine breakdown to HMG-CoA (e.g. dimethylcrotonyl-CoA) could be directly reduced to produce an isoprene alcohol followed by phosphorylation to enter the isoprenoid pathway post-MVA.

Animals↗

PubMed2001

Caspase remodeling of the spectrin membrane skeleton during lens development and aging.

Terminal differentiation of lens fiber cells resembles the apoptotic process in that organelles are lost, DNA is fragmented, and changes in membrane morphology occur. However, unlike classically apoptotic cells, which are disintegrated by membrane blebbing and vesiculation, aging lens fiber cells are compressed into the center of the lens, where they undergo cell-cell fusion and the formation of specialized membrane interdigitations. In classically apoptotic cells, caspase cleavage of the cytoskeletal protein alpha-spectrin to approximately 150-kDa fragments is believed to be important for membrane blebbing. We report that caspase(s) cleave alpha-spectrin to approximately 150-kDa fragments and beta-spectrin to approximately 120- and approximately 80-kDa fragments during late embryonic chick lens development. These fragments continue to accumulate with age so that in the oldest fiber cells of the adult lens, most, if not all, of the spectrin is cleaved to discrete fragments. Thus, unlike classical apoptosis, where caspase-cleaved spectrin is short lived, lens fiber cells contain spectrin fragments that appear to be stable for the lifetime of the organism. Moreover, fragmentation of spectrin results in reduced membrane association and thus may lead to permanent remodeling of the membrane skeleton. Partial and specific proteolysis of membrane skeleton components by caspases may be important for age-related membrane changes in the lens.

Aging↗

PubMed2002

Nutrition Society Medal lecture. The role of the skeleton in acid-base homeostasis.

Nutritional strategies for optimising bone health throughout the life cycle are extremely important, since a dietary approach is more popular amongst osteoporosis sufferers than drug intervention, and long-term drug treatment compliance is relatively poor. As an exogenous factor, nutrition is amenable to change and has relevant public health implications. With the growing increase in life expectancy, hip fractures are predicted to rise dramatically in the next decade, and hence there is an urgent need for the implementation of public health strategies to target prevention of poor skeletal health on a population-wide basis. The role that the skeleton plays in acid-base homeostasis has been gaining increasing prominence in the literature; with theoretical considerations of the role alkaline bone mineral may play in the defence against acidosis dating as far back as the late 19th century. Natural, pathological and experimental states of acid loading and/or acidosis have been associated with hypercalciuria and negative Ca balance and, more recently, the detrimental effects of 'acid' from the diet on bone mineral have been demonstrated. At the cellular level, a reduction in extracellular pH has been shown to have a direct enhancement on osteoclastic activity, with the result of increased resorption pit formation in bone. A number of observational, experimental, clinical and intervention studies over the last decade have suggested a positive link between fruit and vegetable consumption and the skeleton. Further research is required, particularly with regard to the influence of dietary manipulation using alkali-forming foods on fracture prevention. Should the findings prove conclusive, a 'fruit and vegetable' approach to bone health maintenance may provide a very sensible (and natural) alternative therapy for osteoporosis treatment, which is likely to have numerous additional health-related benefits.

Acid-Base Equilibrium↗

PubMedDate not supplied

Lead in bone. IV. Distribution of lead in the human skeleton.

Flameless atomic absorption spectroscopy was used to measure lead concentrations in samples from 5 selected human skeletal sites (tibia, skull, rib, ilium, and vertebra) obtained from 134 hospital autopsies. Lead was distributed unequally among the different bones in distinct patterns that were age-, and to some extent, sex-dependent. To estimate lead concentration of the entire skeleton, all skeletal bones were divided into 5 groups based on their approximate compact/trabecular bone ratios, considering each of our 5 sampled sites to be the prototype for each such group. Regression analysis of the 10 possible bone site pair values at different ages yielded age-related constants. These constants were incorporated into an equation we developed that can be used both to estimate mean skeletal lead concentration (Pb) of the entire body skeleton and also to predict the lead concentration at any of the other 4 bone sites if any 1 of the 5 is measured. Applications of these data to in vivo bone lead measurements are detailed with respect to selection of the site to be measured, estimation of total skeletal lead burden, anticipated variations or error, and dependence of these factors on age and sex of the sampled population.

Adolescent↗

PubMed2004

Do sporting activities convey benefits to bone mass throughout the skeleton?

It is well known that sport and exercise play an important role in stimulating site-specific bone mineral density (BMD). However, what is less well understood is how these benefits dissipate throughout the body. Hence, the aim of the present study was to compare the BMD (recorded at nine sites throughout the skeleton) of 106 male athletes (from nine sports) with that of 15 male non-exercising age-matched controls. Given that BMD is known to increase with body mass and peak with age, multivariate and univariate analyses of covariance were performed to compare the BMD of the nine sports groups with controls (at all sites) using body mass and age as covariates. Our results confirmed a greater adjusted BMD in the arms of the upper-body athletes, the right arm of racket players and the legs of runners (compared with controls), supporting the site-specific nature (i.e. specific to the externally loaded site) of the bone remodelling response (all P <0.01). However, evidence that bone mass acquisition is not just site-specific comes from the results of the rugby players, strength athletes, triathletes and racket players. The rugby players' adjusted BMD was the greatest of all sports groups and greater than controls at all nine sites (all P <0.01), with differences ranging from 8% greater in the left arm to 21% in the lumbar spine. Similarly, the strength athletes' adjusted BMD was superior to that of controls at all sites (P <0.05) except the legs. The adjusted BMD of the triathletes was significantly greater than that of the controls in both the arms and the legs as well as the thoracic and lumbar spine. The racket players not only had significantly greater right arm BMD compared with the controls but also a greater BMD of the lumbar spine, the pelvis and legs. In contrast, the low-strain, low-impact activities of keep-fit, cycling and rowing failed to benefit BMD compared with the age-matched controls. These results suggest that sporting activities involving high impact, physical contact and/or rotational forces or strains are likely to convey significant benefits not only to the loaded sites, but also to other unloaded peripheral and axial sites throughout the skeleton.

Absorptiometry, Photon↗