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PubMed1998

Development of bony acetabulum in newborns with developmental hip dysplasia.

Trend in the development of bony acetabulum in newborns with developmental hip dysplasia was examined during the first year of life. The study comprised 120 newborns with developmental hip dysplasia. The degree of dysplasia was determined by measuring the acetabular angle (AC) on X-rays of the hips in the anteroposterior projection. The experimental trend curve was most adequate for both the whole group and each subject. The coefficient of trend was assessed by specially designed iterative method. The exhibited trend form allows the extrapolation and prognosis of treatment outcome already after 3-5 measurements of the AC angle. The applied iterative method for the determination of the coefficient of exponential trend iterated rather quickly. The chosen form of the trend curve proved to be adequate for manifestations in which a constant value is expected after a longer period of time. The exponential curve represents a mathematical model of the acetabular development dynamics, with allometric exponents and coefficients of the equation being numerical parameters that define developmental changes. As the AC angle reaches the constant value with the closure of triradiate cartilage, this parameter is an objective measure of the development of bony acetabulum. When assessing the acetabular growth in developmental dysplasia it is necessary to bear in mind that duration, specific position and quantity of newly formed and remodelled bone are determined genetically, and that external factors have a significant influence on the definitive formation.

Acetabulum↗
PubMedDate not supplied

Effects of isoflurane on measurements of delayed lumininescence in Acetabularia acetabulum.

The volatile halogenated methyl ethyl ether, isoflurane, used as an anaesthetic, inhibits actin-based dynamics directly or indirectly in animal cells. In plant cells, most intracellular movements are related to actin pathways. We have used isoflurane in a unicellular alga, Acetabularia acetabulum, to test the dynamics of choloroplast organization. By measuring the delayed luminescence, we found that isoflurane worked efficiently in the unicellular organism and showed dose- and time-course-dependent actin-inhibition patterns. When A. acetabulum was treated with saturated solutions of isoflurane in artificial seawater (defined as 100% isoflurane) for 3 or 6 min, the delayed luminescence (DL) was decreased and was never recovered. In contrast, if treated with 75% diluted isoflurane, the DL was firstly inhibited and then recovered several hours later, and if treated with 50% diluted isoflurane, the change of DL was small. Our work proved that isoflurane can affect actin-related pathways in both animals and plants.

Acetabularia↗
PubMed1997

The primary structure of the Cl(-)-translocating ATPase, b subunit of Acetabularia acetabulum, which belongs to the F-type ATPase family.

The genes possibly encoding the b subunit (50 kDa) of the Cl(-)-translocating ATPase of Acetabularia acetabulum were cloned from total RNA and from poly(A)+ RNA and sequenced. The deduced amino acid sequence of the open reading frame consisted of 478 amino acids and showed high similarity to the beta subunit of chloroplast F1-ATPase. Gene fragments encoding the putative beta subunit of chloroplast F1- (273 bp) and mitochondrial F1-ATPases (332 bp) were also cloned from A. acetabulum and sequenced, respectively. The deduced amino acid sequence of the chloroplast F1-ATPase showed 92.5% identity to be primary structure of the b subunit of the Cl(-)-translocating ATPase, while the nucleotide sequences were 79.9% identical. The deduced amino acid sequence of the latter was 77.3% identical to that of the b subunit of the Cl(-)-translocating ATPase and the nucleotide sequences were 67.5% identical. By Northern analysis, these three beta-like genes were demonstrated to be transcribed with different sizes of RNA species. A putative chloroplast F1-beta fragment also hybridized with chloroplast DNA isolated from the organism.

Acetabularia↗
PubMed1985

[Function of the acetabulum of digenetic trematodes, as exemplified by Dicrocoelium dendriticum].

The suckers of animals adhere to the substratum either in air or in aqueous fluids. The varying compressibility of these media causes differences in function, the principles of which are described. The ventral arch of the acetabulum of Dicrocoelium dendriticum, like the remaining body, is limited by the integument, basal lamina and skin muscles. The dorsal arch covers a basal lamina, which is close to a plexus of diagonal, longitudinal and circular muscles. The radical muscles, attached at the ventral basal lamina by thin connective tissue, continue in relatively thick contractile fibers, which split up into several fibrils, which also attached by thin connective tissue at the dorsal basal lamina. In this way the tension of the muscles is likewise distributed over the dorsal and ventral arches of the acetabulum. After contact with the substratum the sucker creates a partial vacuum and attachment by means of the pressure of the radial muscles against the wall of the hole. Because of the fluid content of the hole, the volume does not change much. The dorsal arch of the sucker withstands the pressure of the radical muscles, because its surface area is six times greater than that of the ventral arch and consequently the load is six times less. The sucker, covered with basal lamina, has a constant volume; its layer of muscles resists deformation and supports the stability of the arch.

Animals↗
PubMed2001

Relationships between growth, morphology and wall stress in the stalk of Acetabularia acetabulum.

With carbon particles we analyzed patterns of growth in Acetabularia acetabulum (Lam.) P.C. Silva, a giant unicell famous for classic development studies. We focused on the stalk apex, which generates the stalk, whorls of hairs, and whorls of gametophores. To gain visual and physical accessibility, we amputated the youngest whorls of hair and the original apex and performed experiments on the apex that regenerated. Video analysis indicated that most growth occurred near the tip of the new apex. Less growth occured throughout the cut-interwhorl. We also analyzed cell wall thickness along stalks cleared of cytoplasm. Correlating growth data to wall morphology suggests growth near the apex may be proportional to stress on the cell wall. We propose that turgor-pressure wall stress modulates local apical cell wall growth rates. A supplementary model, relating cell wall curvature and growth rate in the cut-interwhorl, characterizes how the stalk's final dimensions and nearly cylindrical shap may arise. See http://faculty.washington.edu/mandoli/vondassow for supplementary data, analysis, and mathematical appendices. We believe this is the first quantiative description of apex morphogenesis of A. acetabulum.

Acetabularia↗
PubMed1991

A vacuolar ATPase and pyrophosphatase in Acetabularia acetabulum.

Vacuole-rich fractions were isolated from Acetabularia acetabulum by Ficoll step gradient centrifugation. The tonoplast-rich vesicles showed ATP-dependent and pyrophosphate-dependent H(+)-transport activities. ATP-dependent H(+)-transport and ATPase activity were both inhibited by the addition of a specific inhibitor of vacuolar ATPase, bafilomycin B1. A 66 kDa polypeptide present in the preparation cross-reacted with the anti-IgG fractions against the alpha and beta subunits of Halobacterium halobium ATPase and with the antibody against the A subunit (68 kDa subunit) of mung bean vacuolar ATPase. A 56 kDa polypeptide present in the vacuole preparation showed cross-reactivity with the antibody against the B subunit (57 kDa) of mung bean vacuolar ATPase but not with the anti-beta subunit of H. halobium ATPase. A 73 kDa polypeptide cross-reacted with the antibody against inorganic pyrophosphatase of mung bean vacuoles. These results suggest that vacuolar membrane of A. acetabulum equipped energy transducing systems similar to those found in other plant vacuoles.

Acetabularia↗
PubMed1997

Exchangeability of the b subunit of the Cl(-)-translocating ATPase of Acetabularia acetabulum with the beta subunit of E. coli F1-ATPase: construction of the chimeric beta subunits and complementation studies.

The gene encoding the b subunit of the Cl(-)-translocating ATPase (aclB) was isolated from total RNA and poly(A)+ RNA of Acetabularia acetabulum and sequenced (total nucleotides of 3038 bp and an open reading frame with 478 amino acids). The deduced amino acid sequence showed high similarity to the beta subunit of the F type ATPases, but was different in the N-terminal 120 amino acids. The role of the N-terminal region was investigated using an F -ATPase beta-less mutant of E. coli, JP17. The JP17 strain expressing the aclB could not grow under conditions permitting oxidative phosphorylation, although ACLB was detected in the membrane fraction. The beta subunit was divided into three portions: amino acid position from 1 to 95 (portion A), 96 to 161 (portion B) and 162 to the C-terminus (portion C). The corresponding regions of ACLB were designated as portions A' (from 1 to 106), B' (from 107 to 172) and C' (from 173 to 478). Chimeric proteins with combinations of A-B'-C', A-B-C' and A'-B-C restored the function as the beta subunit in E. coli F0F1-complex, but those with combinations of A'-B'-C and A-B'-C had no function as the beta subunit. These findings suggested that portion B plays an important role in the assembly and function of the beta subunit in the F0F1-complex, while portion B' of ACLB exhibited inhibitory effects on assembly and function. In addition, portion A was also important for interaction of the beta subunit with the alpha subunit in E. coli F0F1-complex. These findings also suggested that the b subunit of the Cl(-)-translocating ATPase of A. acetabulum has a different function in the Cl(-)-translocating ATPase complex, although the primary structure resembled to the beta subunit of the F1-ATPase.

Acetabularia↗
PubMed1996

kurkku, a Phenotype of Acetabularia acetabulum That Is Arrested in Vegetative Growth, Can Be Rescued with Wild-Type Cytoplasm.

We isolated several spontaneous phenotypes in the giant unicell Acetabularia acetabulum that have vegetative terminal morphologies. Because they arrest in vegetative development, these cell lines are effectively immortalized. However, they had to be rescued before they could be studied via classical genetics because no heterozygotes from the original self-crosses were found, that is, the wild-type siblings yielded only wild-type progeny. We attempted to rescue these phenotypes in three ways: by amputating the cell apex, by "piggybacking" the mutant nucleus through development in a binucleate heterokaryon, and by replacing the abnormal apex with a wild-type apex. We used one of our immortal cell lines, kurkku, which has a terminal phenotype consistent with arrest early in the juvenile phase of vegetative development, as a prototype for these rescue methods. The kurkku phenotype segregated 1:3 in the original self-cross in which it arose as if it were a single, recessive Mendelian trait. Although amputation failed to rescue kurkku, we succeeded in compensating for the defect both in binucleate heterokaryons and in apical grafts to wild-type cells. kurkku was always recovered in the progeny of the self-crosses of these grafts. These unique ways of analyzing vegetative mutants, combined with the ability to then perform classical genetics, may make A. acetabulum a powerful unicellular model system for the study of vegetative phase change in plants.

Journal Article↗
PubMed2005

Development and organization of the central vacuole of Acetabularia acetabulum.

* Here we analyzed the shape of the central vacuole of Acetabularia acetabulum by visualizing its development during diplophase (from juvenility through reproduction) and haplophase (from meiosis through mating). * Light microscopy and whole-organism applications of a pH-sensitive dye, neutral red, were used to visualize the anatomy of the central vacuole. We studied connectivity within the thallus by locally applying dye to morphologically distinct regions (rhizoid, stalk, apex, hairs) and observing dye movements. * In vegetative thalli most of the rhizoid, stalk and young hairs stained with dye. In reproductive structures (caps, gametangia) dye also stained the majority of the interiors. When applied to small areas, dye moved at different rates through each region of the thallus (e.g. within the stalk). Dye moved from younger hairs, but not from older hairs, into the stalk. Errors in incorporation of central vacuole into gametangia occurred at <10(-5). * These data indicate that the central vacuole of A. acetabulum is a ramified polar organelle with, potentially, a gel-like sap that actively remodels its morphology during development.

Acetabularia↗
PubMed1996

Coordination of cellular events that precede reproductive onset in Acetabularia acetabulum: evidence for a 'loop' in development.

Amputated apices from vegetative wildtype cells of the uninucleate green alga Acetabularia acetabulum can differentiate a reproductive structure of 'cap' in the absence of the nucleus (Hämmerling, J. (1932) Biologisches Zentralblatt 52, 42-61). To define the limits of the ability of wildtype cells to control reproductive differentiation, we determined when during development apices from wildtype cells first acquired the ability to make a cap in the absence of the nucleus and, conversely, when cells with a nucleus lost the ability to recover from the loss of their apices. To see when the apex acquired the ability to make a cap without the nucleus, we removed apices from cells varying either the developmental age of the cells or the cellular volume left with the apex. Cells must have attained the adult phase of development before the enucleate apex could survive amputation and make a cap. Apices removed from cells early in adult growth required more cell volume to make a cap without the nucleus than did apices removed from cells late in adult growth. To define the limits of the cell to recapitulate development when reproduction falters, we analyzed development in cells whose caps either had been amputated or had spontaneously aborted. After loss of the first cap, cells repeated part of vegetative growth and then made a second cap. The ability to make a second cap after amputation of the first one was lost 15-20 days after cap initiation. Our data suggest that internal cues, cell age and size, are used to regulate reproductive onset in Acetabularia acetabulum and add to our understanding of how reproduction is coordinated in this giant cell.

Acetabularia↗
PubMed1994

[Roles of anions in cells: studies on a Cl(-)-translocating ATPase and sulfate uptake system in Acetabularia acetabulum].

Biochemical and molecular biological approaches to two anion translocators, a Cl(-)-translocating ATPase and sulfate permease were described for Acetabularia acetabulum, a unicellular marine alga. The primary structures of an almost complete cDNA clone of the 50 kDa subunit and a partial cDNA clone of the 54 kDa subunit of the Cl(-)-ATPase were highly similar to the beta and alpha subunits of the F type ATPase, respectively. A partial cDNA clone encoding the alpha subunit of chloroplast ATPase, and partial cDNA clones coding for the beta subunits of chloroplast and mitochondrial ATPases were also obtained from A. acetabulum. The presence of a small multigene family for the F type ATPases with different ion specificities was strongly suggested for the organism. Sulfate uptake system in this organism was also studied and partial cDNA clones encoding CysA and sulfate binding proteins were obtained. ca. 1.7 kb RNA for cysA gene and 1.55 kb for sbp gene were detected by Northern analysis, respectively. A putative malK gene was also partially cloned.

Acetabularia↗
PubMed2003

Avulsion fracture of the pelvis: separation of the secondary ossification center in the superior margin of the acetabulum.

A 13-year-old female sustained a rare avulsion fracture of the secondary ossification center in the superior margin of the acetabulum as the result of contraction of the reflected head of the rectus femoris muscle. Diagnosis was made from plain films and CT scans with 3D image reconstruction. The patient was treated non-operatively by bed rest with semiflexion of the hip and knee, and appropriate analgesia.

Accidental Falls↗
PubMed1990

Reconstruction of the hypoplastic acetabulum in cementless arthroplasty of the hip.

We describe a new operative technique for reconstruction of deficient acetabular bone which allows the implantation of the socket of a total hip replacement at the level of the true acetabulum. The results of 61 such operations in 50 patients are reviewed. The average follow up was 45 months (minimum 36 months). All grafts had united by 6 months and there was no failure of the bone grafts or acetabular loosening. The clinical results are encouraging. Special attention is paid to the use of an L-shaped graft taken from the femoral head and neck.

Acetabulum↗
PubMed1991

Case report 696: Chondroblastoma of the right acetabulum and superior pubic ramus.

A case of chondroblastoma involving the right acetabulum and superior pubic ramus in a 60-year-old man has been presented. Tissue was obtained by open biopsy. The clinical and radiographic characteristics of chondroblastoma in general, and this tumor in particular, were discussed. The histopathology and differential diagnosis were also considered. The relatively uncommon site of the tumor and its occurrence in an older patient made the radiographic diagnosis difficult, and other possibilities were discussed.

Acetabulum↗
PubMed1977

[The stress of the human hip joint. VII. The distribution of cartilage thickness in the acetabulum and its functional explanation (author's transl)].

The cartilage thickness of the human acetabulum was examined in 10 objects (material from the dissecting room). Cartilage specimens were taken at identical points of the joint and measured by microscope. The greatest thickness is situated in the outer joint edge, with a maximum in the frontal part of the joint roof; the lowest thickness is found at the inner margin of the facies lunata. These results indicate a higher stressing of the outer joint margin. This could be caused by an eccentric position of the hip joint's resultant force, which is shifted towards the edge. Another possible explanation of these results relates to a swelling of the joint cartilage under functional stress. Such a swelling, which has already been proved, would lead to an incongruence of the ball and socket joint, and so to a stronger stressing of the outer joint edge.

Acetabulum↗
PubMed1976

[A new hip milling machine for preparation of the hip acetabulum for total hip prothesis (author's transl)].

The problemes of the exact preparation of the hip acetabulum for implantation of total hip prothesis have caused the development of several milling machines. Two sorts of construction predominate. Their disadvantages, especially the fact, that there is now mechanism, while is able to carry of the milled tissue, gave rise to construct a new milling machine. In cooperation with engineers of the branch mechanical engineering a new model was developed. The characteristic features are described and explained by pictures. The milling basket will be fastened on the ground plate by a quick fastener. In this way we get a hemisphere cavity, which is able to absorb all the milled tissue without any residue. A grasp will be connected with the drive shaft and guarantee an exact and rightangeled direction. The clinical tests have shown, that the new milling machine with the grasp especially is qualified for use in the osteoporotic senil bone too.

Acetabulum↗
PubMed1992

Radiological vignette. Insufficiency fracture of the acetabulum.

An insufficiency fracture (IF) involving the acetabulum is presented. This fracture occurred in a 67-year-old woman who had been hysterectomized and oophorectomized 27 years earlier for a carcinoma of the uterine cervix, and who had received external pelvic irradiation. This IF location has been rarely described earlier, and its awareness should preclude unnecessary aggressive diagnostic procedures especially in patients with osteoporosis and previous pelvic radiotherapy.

Acetabulum↗
PubMed1987

[Initial experience using the new Weill cementless threaded ring in acetabulum replacement].

First experiences with a new threaded ring for acetabulum arthroplasty developed by D. Weill are reported. These experiences are based on 59 implantations, whose clinical courses and complications are lined out. The Weill acetabular arthroplasty turned out to be a very valuable device for both primary and revision hip arthroplasty. It provides all advantages of cementless fixation. The fixation is gained by a selftapping thread on the outside of the titanium ring. Thus a very high primary stability is achieved. A bone grafting possibility in the fossa region is provided. The relative less tolerance of the Weill ring concerning improper orientation predisposing to dislocation is a disadvantage as we experienced.

Acetabulum↗