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Management of the deficient acetabulum using cementless fixation without bone grafting.

Based on the extensive experience with bulk femoral head augmentation of the acetabulum that began in 1973 and the disturbing incidence of failure that has been substantial and progressive, it is argued that sufficient justification, apart from exceptional circumstances, for the use of this reconstructive technique no longer exist. Instead, technical and technologic advances in the use and design of components that stabilize by biointegration now offer a more attractive alternative.

Acetabulum↗

[clinical application of multiplanar and 3D reconstruction of spiral CT in diagnosis of acetabulum fractures].

This review describes recent visualizations of computed tomography for the diagnosis of acetabular fractures. The techniques of conventional and helical-CT for the imaging of the acetabulum are compared. Furthermore, the different methods of multiplaner and three-dimensional reconstructions e.g. shaded surface display, maximum intensity projection, and volume rendering are presented. Figures of each method are demonstrated and the diagnostic potential of multiplanar and three-dimensional imaging for fractures of the pelvis is discussed.

Acetabulum↗

The histological appearance of the periprosthetic capsule in failed total hip arthroplasty differs depending on the presence of polyethylene acetabulum destruction, iliac bone damage and presence of infection.

Aseptic loosening of the prosthesis is the most common complication of the total hip replacement. The tissues resected on revision surgery often contain polyethylene debris, originating from the worn prosthesis, as well as the fragments of acrylic cement. These foreign bodies are accompanied by various patterns of inflammatory reaction. We compared the elements of the histological picture of periprosthetic capsules from 20 patients with the clinical data, the appearance of the failed prosthesis and the state of the surrounding bone. As a result, we were able to identify characteristic morphological features linked with the aseptic implant loosening compared to the infection group. Among the aseptic implant loosening cases, those with the polyethylene acetabulum damage were associated with the more florid giant cell reaction and diffuse hyalinization of granulation tissue. The iliac bone damage was usually accompanied by more abundant cement fragments, lymphoid infiltrate and solid acellular islands of hyaline. Thus we suspect, that there are at least two mechanisms leading to aseptic failure of the total hip replacement.

Acetabulum↗

Lesions of the sciatic nerve in fractures of the acetabulum.

Between 1982 and 1992 a total of 211 fractures of the acetabulum were operated. There was lesion of the sciatic nerve in 21 cases, the pathogenesis and evolution of which were studied. Clinical follow-up was obtained at least 2 years after occurrence of neurological deficit and supported in 13 cases by electromyography. Based on an analysis of the literature and of these series it is observed how spontaneous recovery of paralysis is not rare, even if it requires a long period of time. The presence of various levels of lesion, which are not easily diagnosed, and which are not easily attacked surgically, calls for a prudent attitude with regard to neurolysis.

Acetabulum↗

[Gluteal posterior approach for surgery of the acetabulum].

PURPOSE OF THE STUDY: This approach was developed to avoid gluteus maximus muscle injury which is divided when using the common Langenbeck-Kocher approach. The posterior perigluteal approach also provides better visualization of the posterior aspect of the acetabulum. MATERIAL AND METHODS: A semi-circular incision is made from the fascia lata at the anterior aspect of the greater trochanter and then directed to the posterio-superior iliac spine. The gluteus maxirnus is then simply retracted medially with blunt retractors. Sixty eight acetabular fractures have been operated with this approach including both mixed and complex fractures of the posterior column. Occasionally fractures of both columns have been operated in two procedures, one posterior and then a second anterior approach. RESULTS: The posterior perigluteal approach preserves gluteus maximus muscle tone. It seems to avoid post-operative ossification. CONCLUSION: We propose an approach which, compare to the Langenbeck- Kocher approach, is less traumatic, and as easy to perform.

Acetabulum↗

Wear of the epiphysis-acetabulum in total hip arthroplasty: a review of the literature.

Problems related to the use of total hip arthroplasty and the properties of the materials used to make prostheses have encouraged wear phenomena of the epiphysis-acetabulum combination of international importance and acknowledgement. Based on a review of the literature, the authors analyze the most recent years of study of wear phenomena and discuss the choice of materials to be used in total hip arthroplasty implant, with particular interest in any potential defects.

Acetabulum↗

[Osteochondritis dissecans of the acetabulum].

A case of osteochondritis dissecans (OD) of the acetabulum in a 14-year-old girl is presented. The initial clinical manifestation was hip pain and restricted movements of the joint. Magnetic Resonance Imaging confirmed the diagnosis. The patient was treated conservatively, using crutches. One year after the first examination, no clinical improvements were found. X-rays of the hip showed increased sclerosis around the osteochondritis-segment, indicating incipient healing. The patient is still conservatively treated, with regular clinical examinations. The diagnosis should be remembered in the case of patients with unexplained hip-pain, and may require magnetic resonance imaging for confirmation.

Acetabulum↗

[Transverse and T fractures with fracture of the posterior wall of the acetabulum. Results of orthopedic and surgical treatment. Apropos of 52 cases].

Fifty two cases of transverse and T fractures associated with a posterior wall fracture of the acetabulum were followed after conservative and surgical treatment. The mean follow-up was 3.5 years. There was marked displacement in 71% of cases, and a transverse fracture of the acetabular roof in 48% of case. There was no joint congruence in 50% of cases. The conservative and surgical results are the same without anatomical reduction, but the functional result seems better after surgical treatment with perfect reduction. However conservative management is necessary when anatomical reduction is impossible.

Acetabulum↗

The roles of light and the nucleus in the regulation of reproductive onset in Acetabularia acetabulum.

At reproductive onset the marine green alga Acetabularia acetabulum (L.) P.C. Silva redirects growth from vertical elongation of the axis of the plant to lateral expansion of a disk-shaped reproductive structure, the "cap." We used amputation to synchronize cap initiation and to facilitate investigation of the light requirements during amputation-induced cap initiation. Following amputation of a nascent cap, most plants initiate one whorl of vegetative hairs and then a cap. Both hair and cap initiation required photosynthesis, as indicated by studies with 3-(3',4'-dichlorophenyl)-1, 1-dimethylurea, but did not require the nucleus. Amputation-induced hair initiation occurred in red light, but 10 min of blue light given in a background of red light significantly increased hair initiation, supporting previous studies that hair initiation is a blue-light-triggered photomorphogenic event. Amputation-induced cap initiation also occurred in red light, but daily 10-min flashes of blue light given in a background of red light did not significantly enhance cap initiation. We also examined the light requirements of intact plants at each phase of development. In the absence of blue light, juveniles and adults with </=13.7 +/- 4.3 whorls of hairs arrested in development and failed to initiate caps. In contrast, very late adults with >/=13.7 +/- 4.3 whorls of hairs initiated caps in the absence of blue light, suggesting that there is a point in late adult development beyond which cap initiation does not require blue light. Several plausible interpretations of the role of light and the nucleus in the regulation of reproductive onset are discussed to try to reconcile these data with those in the literature.

Acetabularia↗

Growth inhibition and changes in morphology and actin distribution in Acetabularia acetabulum by phalloidin and phalloidin derivatives.

Effects on morphology and microfilament structure caused by phalloidin, phallacidin, and some semisynthetic phalloidin derivatives were studied in vegetative cells of the green alga Acetabularia acetabulum (L.) Silva. All phalloidin derivatives (except for phalloidin itself) caused growth stop of the alga after 1 day and (except for the fluorescein-labeled phalloidin) death of the cells after 4-7 days. Hair whorl tip growth and morphology as screened by light microscopy, as well as microfilament structure in tips, suggested that growth stop is correlated with a disorganization of actin filaments similar to that recently described for jasplakinolide (H. Sawitzky, S. Liebe, J. Willingale-Theune, D. Menzel, European Journal of Cell Biology 78: 424-433, 1999). Using rabbit muscle actin as a model target protein, we found that the toxic effects in vivo did not correlate with actin affinity values, suggesting that permeation through membranes must play a role. Indeed, the most lipophilic phalloidin derivatives benzoylphalloidin and dithiolanophalloidin were the most active in causing growth stop at ca. 100 microM. In comparison to the concentration of jasplakinolide required to cause similar effects (<3 microM), the two most active phalloidin derivatives exhibited an activity ca. 30 times lower. Nonetheless, lipophilic phalloidin derivatives can be used in algae, and probably also other cells, to modulate actin dynamics in vivo. In addition, we found that the fluorescent fluorescein isothiocyanate-phalloidin is able to enter living algal cells and stains actin structures brightly. Since it does not suppress actin dynamics, we suggest fluorescein isothiocyanate-phalloidin as a tool for studying rearrangements of actin structures in live cells, e.g., by confocal laser scanning microscopy.

Acetabularia↗

Improvement of reconstitution of the Cl(-)-translocating ATPase isolated from Acetabularia acetabulum into liposomes and several anion pump characteristics.

The improved reconstitution of the Mono Q-III fraction, a Cl(-)-translocating ATPase, isolated from Acetabularia acetabulum (Ikeda et al. (1990) Biochemistry 29, 2057-2065) into liposomes rendered transport properties of this enzyme clear. The liposomes were prepared by the reversed-phase method using egg lecithin and cholesterol in a molar ratio of 2:1 and the purified ATPase was incorporated into the liposomes by a dialysis for 3 h. About 80% of the ATPase was incorporated into the liposomes. The weight ratio of the enzyme to lipid was 1:400-600. A sigmoid curve was obtained when the Cl(-)-transport activity of the enzyme was plotted against Cl- concentration. Hill's plot afforded a half-substrate concentration [S]0.5 of 45 mM and a Hill's coefficient n of 2.33. Effects of Br- and F- on the Cl(-)-transport were also examined in the reconstituted system, both halide ions decreased the 36Cl- efflux significantly. These kinetic data are in good agreement with the electrophysiological data presented by Tittor et al. ((1983) J. Membr. Biol. 75, 129-139).

Acetabularia↗

Operative management of metastases to the pelvis and acetabulum.

Bone metastases to the acetabulum and pelvis can be a devastating and debilitating problem. In certain patients, operative reconstruction of the involved hip can lead to maintenance of independence, pain control, and an increase in the overall quality of life for their remaining life span. These procedures are technically challenging and are associated with a higher complication rate than that for patients having surgery for nonneoplastic disease. They are probably best performed by surgeons with specific training and expertise in tumor surgery and acetabular reconstruction. With proper patient selection, appropriate component use, and competent surgical technique, good-to-excellent results can be obtained.

Bone Nails↗

Analogous features of delayed luminescence from Acetabularia acetabulum and some solid state systems.

This paper compares some features of the delayed luminescence in the seconds range emitted from an unicellular alga Acetabularia acetabulum and from some solid state systems. Results lead us to think that such delayed luminescence is connected to the dimension of the ordered structures present in both biological and solid state systems. In particular, for the biological system examined, these structures are thought to be those which contribute to the dynamic formation of the cytoskeleton.

Acetabularia↗

A Cl(-)-translocating adenosinetriphosphatase in Acetabularia acetabulum. 1. Purification and characterization of a novel type of adenosinetriphosphatase that differs from chloroplast F1 adenosinetriphosphatase.

ATPases were solubilized from membranes of Acetabularia acetabulum using nonanoyl-N-methylgluconamide and purified by ion-exchange and gel permeation chromatography. Three fractions of ATPase, Mono Q-I, -II, and -III, were separated. Activity in fraction Mono Q-I was very labile and could not be accurately determined. Fractions Mono Q-II and -III had specific activities of 0.6 and 6 units/mg of protein, respectively. By SDS-polyacrylamide gel electrophoresis, isoelectric focusing, and peptide mapping, it was shown that fractions Mono Q-II and -III consisted of the same polypeptides with molecular masses of 54K (a-subunit) and 50K (b-subunit). Fractions Mono Q-II and -III had the following catalytic properties: pH optimum at 6.0; substrate specificity, ATP = GTP = ITP much greater than UTP = CTP (Km for ATP 0.6 mM); divalent cation requirement, Mn2+ = Mg2+ greater than Co2+ greater than Zn2+ much greater than Ca2+, Ni2+. Both activities were inhibited by monovalent anions, while monovalent cations had neither inhibitory nor stimulatory effects. Orthovanadate inhibited both activities to 50% at 1 mM, and the most effective inhibitor of both was azide (95% inhibition at 100 microM). An enzyme-phosphate complex was formed after incubation of fraction Mono Q-III with [gamma-32P]ATP. The CF1-ATPase subcomplexes were isolated from the same organism and compared with the fraction Mono Q-III. Data supported the difference of fraction Mono Q-III from CF1-ATPase.

Acetabularia↗

A Cl(-)-translocating adenosinetriphosphatase in Acetabularia acetabulum. 2. Reconstitution of the enzyme into liposomes and effect of net charges of liposomes on chloride permeability and reconstitution.

The Mono Q-III fraction, a Mg2(+)-ATPase, isolated from Acetabularia acetabulum was reconstituted into liposomes of various net charges prepared by the reversed-phase method and tested for a Cl(-)-translocating activity. The liposomes from a mixture of egg lecithin, dicetyl phosphate, and cholesterol (63:18:9 mole ratio, negative liposomes) and from a mixture of egg lecithin and cholesterol (63:9 mole ratio, neutral liposomes) were less leaky than positive liposomes from asolectin, and from a mixture of egg lecithin, stearylamine, and cholesterol (63:18:9 mole ratio). A significant increase in 36Cl- efflux from the negative and neutral liposomes was observed by addition of ATP in the presence of valinomycin after incorporation of the enzyme by short-term dialysis. The ATP-driven 36Cl- efflux was inhibited by addition of azide, an inhibitor of the ATPase. The preincubation of the enzyme with phenylglyoxal, an arginine-modifying reagent, inactivated ATP-mediated 36Cl- efflux, but the ATPase activity of the preparation was not affected. When chloride was replaced by 35SO4(2)-, no ATP-dependent 35SO4(2)- efflux was detectable from the proteoliposomes. Proton-translocating activity of the enzyme was also tested, and no fluorescent quenching of 9-ACMA was observed.

Acetabularia↗

Spectroscopic and biochemical analysis of regions of the cell wall of the unicellular 'mannan weed', Acetabularia acetabulum.

Although the Dasycladalean alga Acetabularia acetabulum has long been known to contain mannan-rich walls, it is not known to what extent wall composition varies as a function of the elaborate cellular differentiation of this cell, nor has it been determined what other polysaccharides accompany the mannans. Cell walls were prepared from rhizoids, stalks, hairs, hair scars, apical septa, gametophores and gametangia, subjected to nuclear magnetic resonance and Fourier transform infrared spectroscopy, and analyzed for monosaccharide composition and linkage, although material limitations prevented some cell regions from being analyzed by some of the methods. In diplophase, walls contain a para-crystalline mannan, with other polysaccharides accounting for 10-20% of the wall mass; in haplophase, gametangia have a cellulosic wall, with mannans and other polymers representing about a quarter of the mass. In the walls of the diplophase, the mannan appears less crystalline than typical of cellulose. The walls of both diploid and haploid phases contain little if any xyloglucan or pectic polysaccharides, but appear to contain small amounts of a homorhamnan, galactomannans and glucogalactomannans, and branched xylans. These ancillary polysaccharides are approximately as abundant in the cellulose-rich gametangia as in the mannan-rich diplophase. In the diplophase, different regions of the cell differ modestly but reproducibly in the composition of the cell wall. These results suggest unique cell wall architecture for the mannan-rich cell walls of the Dasycladales.

Acetabularia↗