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PubMed1990

Molecular genetic analysis of cytoskeletal proteins in development and implications for the membrane skeleton.

The membrane skeleton of nonerythroid cells may be involved in a variety of processes, including the formation and maintenance of specific membrane-cytoskeletal domains. Although much has been learned about the ultrastructure and protein chemistry of the membrane skeleton, there are few direct tests of the in vivo functions of the constituent proteins of the membrane skeleton. Recent advances in molecular genetic analysis provide techniques for studying the membrane skeleton and its components in vivo. Considered here in brief detail are a variety of genetic techniques that have already been used to study cytoskeletal proteins. These techniques should also prove useful for future study of the membrane skeleton.

Animals↗

PubMed1989

[The importance of the gammagraphic examination of the skeleton in the diagnostic and therapeutic strategy in carcinoma of the prostate].

One hundred and sixty patients with the diagnosis of prostate cancer have been treated at the Research Institute of Clinical and Experimental Oncology in Brno over the last 10 years. The present paper has been devoted to the diagnostics of skeleton by scintigraphy as compared with X-ray examination of bones. Scintiscanning of skeleton was performed on a gamma-graph Picker 500 i, 99mTc pyrophosphate was used and scintiscanning was performed in the usual examination regimen. The highest importance of this examination resides in the fact that the demonstration of bone metastases results, in most cases, in changing therapeutic procedure and thus significantly influences the course of the disease and the patient's fate. In the group of patients the authors detected metastases in the skeleton in 40% during the first examination of skeleton, sometime even after introducing the therapy. The results confirm the necessity of a complex skeleton examination before the onset of therapy in each patient with this kind of diagnosis.

Bone Neoplasms↗

PubMed1988

Association of deoxyribonuclease I with the pointed ends of actin filaments in human red blood cell membrane skeletons.

We have characterized the interaction of bovine pancreatic deoxyribonuclease I (DNase I) with the filamentous (F-)actin of red cell membrane skeletons stabilized with phalloidin. The hydrolysis of [3H]DNA was used to assay DNase I. We found that DNase I bound to a homogenous class of approximately equal to 2.4 X 10(4) sites/skeleton with an association rate constant of approximately 1 X 10(6) M-1 S-1 and a KD of 1.9 X 10(-9) M at 20 degrees C. Phalloidin lowered the dissociation constant by approximately 1 order of magnitude. The DNase I which sedimented with the skeletons was catalytically inactive but could be reactivated by dissociation from the actin. Actin and DNA bound to DNase I in a mutually exclusive fashion without formation of a ternary complex. Phalloidin-treated red cell F-actin resembled rabbit muscle G-actin in all respects tested. Since the DNase I binding capacity of the skeletons corresponded to the number of actin protofilaments previously estimated by other methods, it seemed likely that the enzyme binding site was confined to one end of the filament. We confirmed this premise by showing that elongating the red cell filaments with rabbit muscle actin monomers did not appreciably add to their capacity to bind or inhibit DNase I. Saturation of skeletons with cytochalasin D or gelsolin, avid ligands for the barbed end of actin filaments, did not reduce their binding of DNase I. Furthermore, neither cytochalasin D nor DNase I alone blocked all of the sites for addition of monomeric pyrene-labeled rabbit muscle G-actin to phalloidin-treated skeletons; however, a combination of the two agents did so. In the presence of phalloidin, the polymerization of 300 nM pyrenyl actin on nuclei constructed from 5 nM gelsolin and 25 nM rabbit muscle G-actin was completely inhibited by 35 nM DNase I but not by 35 nM cytochalasin D. We conclude that DNase I associates uniquely with and caps the pointed (slow-growing or negative) end of F-actin. These results imply that the amino-terminal, DNase I-binding domain of the actin protomer is oriented toward the pointed end and is buried along the length of the actin filament.

Actins↗

PubMed1978

Suppression of autochthonous tumors by mixed implantation with Nocardia rubra cell-wall skeleton and related bacterial fractions.

Antitumor activities of the cell-wall skeleton of Nocardia rubra and related bacterial fractions in autochthonous tumor-host system were tested on autografts of spontaneous mammary adenocarcinoma in SHN mice and of 3-methylcholanthrene-induced fibrosarcoma in ICR/JCL mice. The oil-attached cell-wall skeleton of N. rubra was the most effective in suppressing the autografts of the mammary adenocarcinoma but less of the fibrosarcoma, when the autografts were mixed with oil-attached preparation and implanted subcutaneously in the original host, while peptidoglycolipid of Mycobacterium tuberculosis Aoyama B was the most suppressive on the autografts of the fibrosarcoma but not on the mammary tumor autografts. The cell-wall skeleton of Mycobacterium bovis BCG slightly suppressed the autografts of the fibrosarcoma. Presensitization of tumor-bearing mice with the cell-wall skeleton of N. rubra resulted in a more marked suppression on autografts of both tumors than without the presensitization, but local destruction of these tumor autografts did not induce recognizable systemic immunity to the respective tumors. Intralesional injection of cell-wall skeleton of N. rubra showed prolongation of survival days of mice with fibrosarcoma.

Adenocarcinoma↗

PubMed1976

Adjuvant and antitumor activities of Nocardia cell-wall skeletons.

The adjuvant activity of the cell-wall skeletons prepared from eight species (ten strains) of Nocardia was determined by Brunner's method using allogeneic cell-mediated cytotoxicity test. The antitumor activity of the cell-wall skeleton of N. rubra, which showed the most potent adjuvant activity, was examined using EL-4 leukemia and MH-134 hepatoma cells in syngeneic mice. Its results suggest that the cell-wall skeleton of N. rubra is more potent than BCG cell-wall skeleton as the immunotherapeutic agent for cancer immunotherapy in man. The chemical properties of the cell-wall skeleton of N. rubra were also described.

Adjuvants, Immunologic↗

PubMed1994

Radiographic and scintigraphic features of modeling and remodeling in the heterotopic skeleton of patients who have fibrodysplasia ossificans progressiva.

To characterize the radiographic and scintigraphic features of modeling and remodeling in the heterotopic skeleton of patients who have fibrodysplasia ossificans progressiva, radiographs from 47 patients and radionuclide bone scans from 12 of those patients, all of whom had a confirmed diagnosis of the disease, were reviewed. A wide range of normal bone modeling and remodeling features was seen in the heterotopic skeleton of all but the youngest two (age, 1 year) of the 47 patients. Characteristic features of normal bone modeling identified on radiographs of the heterotopic skeleton included: (a) the development of tubular and flat bones with mature cortical and trabecular organization; (b) the presence of well defined cortical-endosteal borders enclosing medullary canals; and (c) the presence of metaphyseal funnelization in isolated ossicles or at sites of synostoses. Characteristic features of normal bone remodeling identified on radiographs of the heterotopic skeleton included: (a) the response of heterotopic bone to weight bearing stress with osteosclerosis of use and osteopenia of disuse, and (b) the resistance of heterotopic bone to fatigue failure with the absence of pathologic fractures and stress fractures. Radionuclide bone scans in 12 patients showed that remodeling of mature heterotopic bone occurred at a rate consistent with that of mature normotopic bone. This study documents the radiographic and scintigraphic features of a heterotopic skeletal system in 47 patients who have fibrodysplasia ossificans progressiva. These data provide additional support for the hypothesis that the genetic defect leading to the formation of a heterotopic skeleton involves normal skeletal morphogenesis at heterotopic sites.

Adolescent↗

PubMed1997

Effect of PMA on the integrity of the membrane skeleton and morphology of epithelial MDCK cells is dependent on the activity of amiloride-sensitive ion transporters and membrane potential.

The signaling pathways from an activation of protein kinase C (PKC) by phorbol myristate acetate (PMA) to the rearrangement of actin-based cytoskeleton and membrane skeleton of epithelial MDCK cells were studied by visualizing the cytoskeletal organization with immunofluorescence microscopy and by measuring intracellular pH, sodium ion concentration and membrane potential with the aid of fluorescent intracellular indicators. Upon PMA treatment the MDCK cells lost their cubic shape and acquired a spindle-like morphology. The stress fibers were depolymerized, and fodrin, the main component of the membrane skeleton, was released from the lateral walls to the cytosol. These changes were accompanied by depolarization of the cells, decrease in the intracellular pH and sodium ion concentration. In order to test the mutual correlation between the PMA-induced alterations we treated the cells with PMA in the presence of channel inhibitors or ionophores and in defined media. The effects of PMA on the membrane skeleton and morphology could be reversed in media lacking Na+ or K+ ions or by hyperpolarizing agents, dimethylamiloride and valinomycin, suggesting that the effects of PMA on the cytoskeleton were dependent on the ion gradients and membrane potential across the cell membrane. Moreover, the morphological changes and instabilization of the membrane skeleton of MDCK cells took place spontaneously without PMA in depolarizing conditions, in potassium gluconate buffer. We suggest that the membrane potential across the cell membrane of MDCK cells together with the activity of amiloride-sensitive cation transporters transmits signals in the protein kinase C (PKC) pathway leading from activation of PKC to fibroblast-like morphology and cytoplasmic localization of membrane skeleton components, features characteristic for cancer cells.

Amiloride↗

PubMed2005

F-81 skeleton from Wadi Mataha, Jordan, and its bearing on human variability in the Epipaleolithic of the Levant.

The discovery of a Middle Epipaleolithic adult skeleton (F-81) at the site of Wadi Mataha in southern Jordan provides new insights into human variability in the Epipaleolithic of the Levant. This paper analyzes the skeletal morphology of Wadi Mataha F-81 in the context of other Epipaleolithic remains from Jordan and Israel to assess the current evidence for morphological variability throughout this period. The F-81 skeleton shares morphological features with earlier Epipaleolithic skeletons from Ohalo and Nahal Ein Gev, and later Natufian populations. Despite the morphological similarities, F-81 extends the range of known variability prior to the Natufian with its unusually small stature and unique combination of morphological characteristics. High levels of cranial and postcranial robusticity suggest that the F-81 individual was physically active and terrestrially mobile. Pronounced bilateral asymmetry in the upper limb suggests significant lateralization of habitual activity. In the context of Epipaleolithic remains, the F-81 skeleton provides preliminary evidence for greater morphological variability, terrestrial mobility, and lateralized habitual behavior prior to the Natufian, and skeletal gracilization between the Middle and Late Epipaleolithic in the Levant.

Adult↗

PubMedDate not supplied

Preliminary description of the Equatorius africanus partial skeleton (KNM-TH 28860) from Kipsaramon, Tugen Hills, Baringo District, Kenya.

A partial skeleton was recovered from middle Miocene Muruyur sediments near Kipsaramon in the Tugen Hills, Baringo District, Kenya. The specimen, representing much of the upper skeleton, comes from locality BPRP#122 dated between 15.58 Ma and 15.36 Ma. It is referable to the middle Miocene hominoid taxon Equatorius africanus. Preliminary descriptions of the partial skeleton are provided. While the anatomy of the wrist, thorax and hindlimb in Equatorius is similar to that of Afropithecus and Proconsul, the morphology of the new skeleton confirms earlier interpretations of greater terrestriality in Equatorius.

Animals↗

PubMedDate not supplied

Three-dimensional skeletonization for computer-assisted treatment planning in radiosurgery.

This paper describes a new algorithm for skeletonization of two- (2D) and three-dimensional (3D) objects based on ridge extraction. Ridges are formed when grassfire fronts collapse during grassfire propagation and they correspond to the locus of skeleton. The iso-distance contours/surfaces of a distance map are analogous to the grassfire fronts. They are locally smooth everywhere except at ridge locations. The new skeletonization algorithm extracts these ridge points based on local curvature measurement and is rotational invariant. It requires one scan of the image for curvature detection in any dimension, and is much faster than thinning methods. Connectivity checks are not required and the algorithm is extensible to higher dimensions. Our 3D skeletonization method is used in a novel algorithm to guide computerized planning of radiosurgical treatment of brain tumors.

Algorithms↗

PubMed2006

Biomechanics: a pneumo-hydrostatic skeleton in land crabs.

Like their aquatic counterparts, terrestrial crabs repeatedly shed their rigid exoskeleton during moulting. But in the case of land crabs, little water is available to provide a temporary hydrostatic skeleton before the new skeleton hardens, and air does not provide the buoyancy necessary to support the animal. Here we show that whenever its exoskeleton is shed, the blackback land crab Gecarcinus lateralis relies on an unconventional type of hydrostatic skeleton that uses both gas and liquid (a 'pneumo-hydrostat'). To our knowledge, this is the first experimental evidence for a locomotor skeleton that depends on a gas. It establishes a new category of hydrostatic skeletal support and possibly a critical adaptation to life on land for the Crustacea.

Air↗

PubMed2000

Evolutionary exploitation of design options by the first animals with hard skeletons.

The set of viable design elements available for animals to use in building skeletons has been fully exploited. Analysis of animal skeletons in relation to the multivariate, theoretical "Skeleton Space" has shown that a large proportion of these options are used in each phylum. Here, we show that structural elements deployed in the skeletons of Burgess Shale animals (Middle Cambrian) incorporate 146 of 182 character pairs defined in this morphospace. Within 15 million years of the appearance of crown groups of phyla with substantial hard parts, at least 80 percent of skeletal design elements recognized among living and extinct marine metazoans were exploited.

Animals↗

PubMed2005

[Princess Anna Vasa--her fascinating life story and skeleton].

The Princess Anna Vasa was born in Sweden in 1568 and spent her first 19 years there. She was the daughter of the Swedish king Johan III and his wife, the Polish Royal Princess Katarina Jagellonica. She was brought up as a Catholic but converted to be a Protestant already in 1583 and remained a fervent Protestant to the end of her life. She was an exceptionally intelligent and extensively educated woman. When her brother became king, Sigismund III of Poland, she accompanied him there. She exerted great influence on Sigismund who was brought up to be a Catholic. She was persistent in her religion, yet working for religious liberty. "The Swedish Princess" was also named "the Queen of Polish Botany". She was never married and she died 57 years old in 1625. For religious reasons her body had to wait 11 years for a funeral of royal standing. The funeral took place in 1636 in St Mary's Church in Torun, Poland. During restoration work at the church in April 1994, Anna Vasa's skeleton was removed from the tomb, and an antropological investigation in order to establish her identity was carried by Dr Andrzej Florkowski at the Dept of Anthrop, Nicholas Copernicus University of Torun. I was invited to Torun to examine her remains in May 1995. The skeleton was in a rather good state of preservation. However, her grave had been plundered at least twice. Her skeleton lacked the right forearm and hand, probably as the result of the pillage of her rings and bracelets. Some other bones and teeth were also missing. At our ocular examination the skeleton revealed a number of anatomical deformations and pathological changes. A conventional radiography and CT of Anna Vasa's skeletal remains was later carried out in 1995 by M. Grzegorzewski, Z. Boron and W. Lasek at the Dept of Radiology, Med. Acad. of Bydgoszcz, Polen. A DNA-analysis was carried out by Dr Anders Götherström at the Archaeol. Res. Lab., Stockholm Univ. An odontological and radiological study was performed by Dr Sigrid I. Kvaal, Dept of Oral path., Univ of Oslo, Norway. 14C (Ua-10417) and delta 13C analyses were carried out by Prof. Göran Possnert at the Angström Lab., Uppsala Univ, Sweden. The article presents results from the different analyses. Anna Vasa's remains were reburied in the restored church in October 1995.

Botany↗

PubMed1977

[Reconstruction of the postcranial skeleton of an infant of Neanderthal man from Kiik-Koba (the Soviet Union) (author's transl)].

The first study concerning the postnatal skeleton of Neanderthal man gives us information about the development of the skeleton of Neanderthal man in the earliest stage of postnatal ontogenetic development. The very good state of preservation of the postcranial skeleton of the infant of Neanderthal man from Kiik-Koba in the Crimea made it possible to carry out for the first time a graphic reconstruction of the entire skeleton in norma frontalis and norma lateralis, in natural size. In this way we have obtained the necessary information for evaluation of body height, for the establishment of body proportions of an infant of Neanderthal man, and for a comparison of these proportions with those of a recent infant of a European that is on the same stage of ontogenetic development.

Anthropology, Physical↗

PubMed1997

Description of the adult skeleton and developmental osteology of the hyperossified horned frog, Ceratophrys cornuta (Anura:Leptodactylidae).

The adult skeleton and tadpole chondrocranium of the leptodactylid frog, Ceratophrys cornuta (Ceratophryinae), are described in detail, including the ontogenetic development of the chondrocranium and the ossification sequence of the skeleton. The chondrocranium of the carnivorous larvae is unique in lacking a frontoparietal fontanelle and possessing a complete dorsal roof of cartilage. Furthermore, the chondrocranium is extremely robust, particularly those elements involved in the feeding mechanism; these include large palatoquadrate cartilages, stout Meckel's, supra-, and infrarostral cartilages, and short, wide, cornua trabeculae. The chondrocranium of C. cornuta resembles that described for Ceratophrys cranwelli, but differs from the chondrocrania reported for the species of Lepidobatrachus. The large adult skull is hyperossified; most elements are fused into a single unit, and nearly all dermal elements are ornamented, casqued, and co-ossified. Calcification is present in nearly every cartilaginous element of the skeleton in larger (older) adults. Several osteological characters previously used in ceratophryine systematics, such as the otic ramus of the squamosal and the columella, are reassessed. Contrary to previous reports, the ossified, dorsal dermal shield above the vertebral column in many ceratophryine anurans is absent in C. cornuta. With few exceptions, the ossification sequence relative to metamorphosis is consistent with those that are known for other anurans. The squamosal arises from three distinct centers of ossification, including an otic element. The frontoparietal arises from two centers of ossification that fuse early in development. A robust postorbital arch is formed primarily by the otic flange of the frontoparietal, which articulates laterally with the medial border of the otic ramus of the squamosal. Changes in the timing of development, or heterochrony, are involved with the evolution of the unusual skull and skeleton of ceratophryine frogs.

Animals↗

PubMed2005

Malformations of the axial skeleton in Museum Vrolik I: homeotic transformations and numerical anomalies.

The Museum Vrolik collection of anatomical specimens in Amsterdam, The Netherlands, comprises over 5,000 specimens of human and animal anatomy, embryology, pathology, and congenital anomalies. Recently, we rediagnosed a subset of the collection comprising dried human trunk skeletons and cranial base preparations presenting with homeotic transformations (vertebral phenotypic shifts) and numerical vertebral anomalies. We identified 11 trunk skeletons with either anterior or posterior homeotic transformations (AHT or PHT), 5 trunk skeletons with either less or more than the normal number of vertebrae, and well over a hundred cranial base preparations with either AHT (atlas-assimilation) or PHT (occipital vertebra). We found that, although homeotic transformations and numerical anomalies are distinct conditions, both can be described in terms of mismatch between homeotic patterning and morphological segmentation of the paraxial mesoderm. Therefore these two processes are perhaps not as tightly linked as they may seem on the basis of recent molecular studies. In homeotic transformations there is a constant mismatch between homeotic patterning and morphological segmentation throughout the affected region of the vertebral column. In numerical anomalies there is a variable mismatch between homeotic patterning and morphological segmentation, either because of stretching or squeezing of the homeotic pattern or because of oligo- or polysegmentation of the presomitic mesoderm (PSM). Homeotic transformations of the axial skeleton have an incidence of about 1%-5%, apart from their occurrence in malformation syndromes. Of the various etiological possibilities, explaining their frequent but mostly sporadic occurrence, maternal hyperthermia seems an attractive candidate.

Animals↗

PubMed1994

Further evidence of lead contamination of Omaha skeletons.

A previous analysis of Omaha skeletons dating between A.D. 1780 and 1820 revealed the presence of lead in all skeletons with high concentrations in children and adult males (Reinhard and Ghazi [1992] Am. J. Phys. Anthropol. 89:183-195). Two likely explanations for the high lead levels were presented: 1) metabolic absorption of lead and 2) diagenetic uptake of lead by the bones from postmortem application of pigments to the corpse. Two types of lead were available to the Omaha tribe: 1) Mississippi Valley type, and 2) non-Mississippi Valley type. It has been suggested that red-lead pigment mixed with mercury sulphide (cinnabar) applied to the corpse may have been one of the sources of lead found in bones. Further isotopic analyses of samples of pigment and metallic lead artifacts associated with the skeletons revealed that non-Mississippi Valley type lead is present in the pigment while Mississippi Valley type lead comes from metallic artifacts. Both lead and mercury were found in the pigment samples, verifying that a lead-based pigment mixed with cinnabar-based pigment was used as a cosmetic by the Omaha. Isotopic analysis of lead in skeletons indicates that the pigment contributed most to lead content of bone. This new evidence clarifies the previous study and suggests specific mechanisms by which lead became incorporated into bone.

Analysis of Variance↗

PubMed2006

Elastic properties of external cortical bone in the craniofacial skeleton of the rhesus monkey.

Knowledge of elastic properties and of their variation in the cortical bone of the craniofacial skeleton is indispensable for creating accurate finite-element models to explore the biomechanics and adaptation of the skull in primates. In this study, we measured elastic properties of the external cortex of the rhesus monkey craniofacial skeleton, using an ultrasonic technique. Twenty-eight cylindrical cortical specimens were removed from each of six craniofacial skeletons of adult Macaca mulatta. Thickness, density, and a set of longitudinal and transverse ultrasonic velocities were measured on each specimen to allow calculation of the elastic properties in three dimensions, according to equations derived from Newton's second law and Hooke's law. The axes of maximum stiffness were determined by fitting longitudinal velocities measured along the perimeter of each cortical specimen to a sinusoidal function. Results showed significant differences in elastic properties between different functional areas of the rhesus cranium, and that many sites have a consistent orientation of maximum stiffness among specimens. Overall, the cortical bones of the rhesus monkey skull can be modeled as orthotropic in many regions, and as transversely isotropic in some regions, e.g., the supraorbital region. There are differences from human crania, suggesting that structural differences in skeletal form relate to differences in cortical material properties across species. These differences also suggest that we require more comparative data on elastic properties in primate craniofacial skeletons to explore effectively the functional significance of these differences, especially when these differences are elucidated through modeling approaches, such as finite-element modeling.

Animals↗