Can we predict which dysplastic hips will require acetabular augmentation during total hip arthroplasty based on pre-operative radiographs?

AIMS: The purpose of this study was to evaluate whether an innovative templating technique could predict the need for acetabular augmentation during primary total hip arthroplasty for patients with dysplastic hips. PATIENTS AND METHODS: We developed a simple templating technique to estimate acetabular component coverage at total hip arthroplasty, the True Cup: False Cup (TC:FC) ratio. We reviewed all patients with dysplastic hips who underwent primary total hip arthroplasty between 2005 and 2012. Traditional radiological methods of assessing the degree of acetabular dysplasia (Sharp's angle, Tönnis angle, centre-edge angle) as well as the TC:FC ratio were measured from the pre-operative radiographs. A comparison of augmented and non-augmented hips was undertaken to determine any difference in pre-operative radiological indices between the two cohorts. The intra- and inter-observer reliability for all radiological indices used in the study were also calculated. RESULTS: Of the 128 cases reviewed, 33 (26%) needed acetabular augmentation. We found no difference in the median Sharp's angle (p = 0.10), Tönnis angle (p = 0.28), or centre-edge angle (p = 0.07) between the two groups. A lower TC:FC ratio was observed in the augmented group compared with the non-augmented group (median = 0.66 versus 0.88, p < 0.001). Intra-observer reliability was found to be high for all radiological indices analysed (interclass correlation coefficient (ICC) > 0.7). However, inter-observer reliability was more variable and was only high for the TC: FC ratio (ICC > 0.7). CONCLUSION: The TC: FC ratio gives an accurate estimate of acetabular component coverage. It can help predict which dysplastic hips are likely to need acetabular augmentation at primary total hip arthroplasty. It has high intra- and inter-observer reliability. Cite this article: Bone Joint J 2017;99-B:445-50.

Thermal sensitivity of mitochondrial respiration efficiency and protein phosphorylation in the clam Mercenaria mercenaria.

The mitochondria of intertidal invertebrates continue to function when organisms are exposed to rapid substantial shifts in temperature. To test if mitochondrial physiology of the clam Mercenaria mercenaria is compromised under elevated temperatures, we measured mitochondrial respiration efficiency at 15 degrees C, 18 degrees C, and 21 degrees C using a novel, high-throughput, microplate respirometry methodology developed for this study. Though phosphorylating (state 3) and resting (state 4) respiration rates were unaffected over this temperature range, respiratory control ratios (RCRs: ratio of state 3 to state 4 respiration rates) decreased significantly above 18 degrees C (p < 0.05). The drop in RCR was not associated with reduction of phosphorylation efficiency, suggesting that, while aerobic scope of mitochondrial respiration is limited at elevated temperatures, mitochondria continue to efficiently produce adenosine triphosphate. We further investigated the response of clam mitochondria to elevated temperatures by monitoring phosphorylation of mitochondrial protein. Three proteins clearly demonstrated significant time- and temperature-specific phosphorylation patterns. The protein-specific patterns of phosphorylation may suggest that a suite of protein kinases and phosphatases regulate mitochondrial physiology in response to temperature. Thus, while aerobic scope of clam mitochondrial respiration is reduced at moderate temperatures, specific protein phosphorylation responses reflect large shifts in function that are initiated within the organelle at higher temperatures.

Larval dispersal potential of the tubeworm Riftia pachyptila at deep-sea hydrothermal vents.

Hydrothermal vents are ephemeral because of frequent volcanic and tectonic activities associated with crust formation. Although the larvae of hydrothermal vent fauna can rapidly colonize new vent sites separated by tens to hundreds of kilometres, the mechanisms by which these larvae disperse and recruit are not understood. Here we integrate physiological, developmental and hydrodynamic data to estimate the dispersal potential of larvae of the giant tubeworm Riftia pachyptila. At in situ temperatures and pressures (2 degrees C and 250 atm), we estimate that the metabolic lifespan for a larva of R. pachyptila averages 38 days. In the measured flow regime at a fast-spreading ridge axis (9 degrees 50' N; East Pacific Rise), this lifespan results in potential along-ridge dispersal distances that rarely exceed 100 km. This limited dispersal results not from the physiological performance of the embryos and larvae, but instead from transport limitations imposed by periodic reversals in along-ridge flows and sustained episodes of across-ridge flow. The lifespan presented for these larvae can now be used to predict dispersal under current regimes at other hydrothermal vent sites.

High macromolecular synthesis with low metabolic cost in Antarctic sea urchin embryos.

Assessing the energy costs of development in extreme environments is important for understanding how organisms can exist at the margins of the biosphere. Macromolecular turnover rates of RNA and protein were measured at -1.5 degrees C during early development of an Antarctic sea urchin. Contrary to expectations of low synthesis with low metabolism at low temperatures, protein and RNA synthesis rates exhibited temperature compensation and were equivalent to rates in temperate sea urchin embryos. High protein metabolism with a low metabolic rate is energetically possible in this Antarctic sea urchin because the energy cost of protein turnover, 0.45 joules per milligram of protein, is 1/25th the values reported for other animals.

Gene expression and enzyme activities of the sodium pump during sea urchin development: implications for indices of physiological state.

The sodium pump consumes a large portion of the metabolic energy (40%) in sea urchin larvae. Understanding the developmental regulation of ion pumps is important for assessing the physiological state of embryos and larvae. We sequenced a partial cDNA clone (1769 bp) from the sea urchin Strongylocentrotus purpuratus and found it to contain the C-terminal portion of an open reading frame coding for 195 amino acids that exhibited high sequence similarity (89%) to invertebrate alpha-subunits of the Na+,K+-ATPase sodium pump. Northern blots using the 3' untranslated region of this cDNA specifically recognized a 4.6-kbp transcript under high stringency. During embryonic development, a rapid increase in levels of this mRNA transcript during gastrulation (25 h postfertilization) was paralleled by a concomitant increase in the total enzymatic activity of Na+,K+-ATPase. Expression of this subunit during gastrulation increased to a maximum at 36 h, followed by a rapid decline to trace levels by 60 h. The rate of removal of the transcript from the total RNA pool after 36 h closely followed a first-order exponential decay model (r2= 0.988), equivalent to a degradation rate of 7.8% h(-1). By 83 h, transcription of the alpha-subunit gene was low, yet sodium pump activity remained high. Molecular assays for the expression of this gene would underestimate sodium pump activities for assessing physiological state because of the temporal separation between maximal gene expression in a gastrula and maximal enzyme activities in the later larval stage. This finding illustrates the difficulty of using molecular probes for assessing the physiological state of invertebrate larvae.

Nucleotide sequence variability in the nontranscribed spacer of the rRNA locus in the oyster parasite Perkinsus marinus.

We examined the sequence variability of the nontranscribed spacer (NTS) and internal-transcribed spacer (ITS1 and ITS2) domains of the rRNA locus of Perkinsus marinus from Maryland, Florida, and Louisiana. The sequence of P. marinus DNA including the 5S rRNA, NTS, small subunit (SSU) rRNA, ITSI, and ITS2 regions confirmed their contiguity in the rRNA locus and revealed differences at 28 positions with the SSU rRNA sequences published earlier. The 307-bp polymerase chain reaction (PCR)-amplified fragments from the NTS domain of the various P. marinus isolates revealed the presence of 2 distinct sequences, designated as types I and II, that differed at 6 defined nucleotide positions. Based on these differences, nested PCR and restriction enzyme digests were used to distinguish between the 2 types. Sequences of the ITS1 and ITS2 domains of samples from either NTS type I (n = 3) or type II (n = 3) showed no variation and were identical to published sequences. Frequencies of the P. marinus NTS sequence types I and II in infected oysters varied with the geographic origin of the samples. All Maryland samples examined (n = 19) corresponded to the NTS type I sequence, the type II was the most frequent in the Florida samples (n = 17), and both types were about equally represented in the Louisiana samples (n = 19), with both sequence types found in individual oyster specimens. Although it has been suggested that P. marinus is diploid, it remains to be determined if both NTS sequence types can be present in a single P. marinus trophozoite.

Energy metabolism during embryonic development and larval growth of an Antarctic sea urchin.

Developmental energetics of an Antarctic sea urchin, Sterechinus neumayeri, were quantified to describe the physiological bases underlying ontogenetic changes in metabolic rate at extreme cold temperatures (-1.5 degrees C). Rates of development from a four-arm to a six-arm larval stage were not affected by food availability. The respiratory cost of development to the six-arm larval stage (day 60) was 14.0 mJ for fed larvae and 8.2 mJ for unfed larvae. We observed three phases of metabolic regulation during development. During embryogenesis (day 0-22), increasing metabolic rates were proportional to increases in cell numbers. During early larval development (day 22-47), the differences in respiratory rate between fed and unfed larvae were not accounted for by cell number, but by cell-specific metabolic rate (respiratory rate normalized to DNA content). Once an advanced larval stage had been reached (day 47-60), cell-specific respiratory rate and mitochondrial densities (citrate synthase activity normalized to DNA content) were more equivalent between fed and unfed larvae, suggesting that size-specific metabolic rates were determined at a level of physiological regulation that was independent of cell numbers or feeding history.

A semiquantitative PCR assay for assessing Perkinsus marinus infections in the eastern oyster, Crassostrea virginica.

A 3.2-kb fragment of Perkinsus marinus DNA was cloned and sequenced. A noncoding domain was identified and targeted for the development of a semiquantitative polymerase chain reaction (PCR) assay for the presence of P. marinus in eastern oyster tissues. The assay involves extracting total DNA from oyster hemolymph and using 1 microgram of that DNA as template in a stringent PCR amplification with oligonucleotide primers that are specific for the P. marinus 3.2-kb fragment. With this assay, we can detect 10 pg of total P. marinus DNA per 1 microgram of oyster hemocyte DNA with ethidium bromide (EtBr) staining of agarose gels, 100 fg total P. marinus DNA with Southern blot autoradiography, and 10 fg of total P. marinus DNA with dot-blot hybridizations. We have used the sensitivity of the PCR assay to develop a method for estimating the level of P. marinus DNA in oyster hemolymph and have successfully applied this technique to gill tissues. Our semiquantitative assay uses a dilution series to essentially titrate the point at which a P. marinus DNA target is no longer amplified in a sample. We refer to this technique as "dilution endpoint" PCR. Using hemocytes obtained by withdrawing a 1-ml sample of hemolymph, this assay provides a nondestructive methodology for rapidly screening large numbers of adult oysters for the presence and quantification of P. marinus infection levels. This technique is applicable to other tissues (gills) and could potentially be applied to DNA extracts of whole larvae or spat.

A divergent cDNA homologue of the c-myc proto-oncogene in the eastern oyster Crassostrea virginica: implications for Myc evolution.

The polymerase chain reaction was used to identify myc-like cDNA fragments from several marine invertebrate phyla. A PCR clone produced from the eastern oyster Crassostrea virginica was subsequently used to screen a larval cDNA library, and a 1.9-kb cDNA clone was isolated and sequenced. The putative amino acid sequence encoded by this clone evidences a leucine zipper at its predicted carboxyl-terminus and has an overall structural similarity to vertebrate c-myc proto-oncogenes with several regions of high amino acid similarity. However, this oyster cDNA clone lacks the necessary amino acid conservation in the critical functional domains of Myc and thus is unlikely to function intracellularly in the oyster as a true homologue of vertebrate c-myc. We propose that the oyster cDNA clone described here represents a gene that has been derived from the same ancestral gene that eventually gave rise to vertebrate c-myc. Despite the apparent critical importance of the c-myc proto-oncogene in regulating cellular activities, these data suggest that the c-myc gene: (1) is unique to deuterostome phyla, and (2) assumed its critical role in regulating cell cycle activities at the divergence of the deuterostome ancestors from other protostomes during the Cambrian explosion. In support of these conclusions we present a functional model for the evolution of the Myc gene.

Effect of estradiol and progesterone on c-myc expression in the sea star testis and the seasonal regulation of spermatogenesis.

Analysis of the expression of cell cycle control genes provides a sensitive assay for mitotic and meiotic progression under experimental conditions. Transcription of the c-myc proto-oncogene and thymidine incorporation into DNA were both used to assay the mitogenic effects of estradiol and progesterone on the testicular germinal epithelium of the starfish Asterias vulgaris. Experimental in vitro studies during the annual spermatogenic cycle show that testes are not sensitive to mitotic stimulation by estradiol alone, whereas progesterone alone is mitotically inhibitory. The germinal epithelium can only be mitotically stimulated by estradiol after pretreatment with progesterone. The net increase in mitotic activity following a progesterone to estradiol transfer is dependent on the length of progesterone pretreatment. Overall, the seasonal pattern of testicular estradiol and progesterone levels evident in field populations of A. vulgaris (Hines et al., 1992a: Endocrinology 100:1468-1471) do not appear to be responsible for initiating spermatogonial mitosis at the onset of the annual spermatogenic cycle. Expression rates of the c-myc proto-oncogene are substantially more sensitive than thymidine incorporation in quantifying mitotic activity. Measuring proto-oncogene expression provides an ideal experimental approach to investigations of the regulatory mechanisms that control growth and reproduction in marine organisms.

Animal lectins as self/non-self recognition molecules. Biochemical and genetic approaches to understanding their biological roles and evolution.

In recent years, the significant contributions from molecular research studies on animal lectins have elucidated structural aspects and provided clues not only to their evolution but also to their multiple biological functions. The experimental evidence has suggested that distinct, and probably unrelated, groups of molecules are included under the term "lectin." Within the invertebrate taxa, major groups of lectins can be identified: One group would include lectins that show significant homology to membrane-integrated or soluble vertebrate C-type lectins. The second would include those beta-galactosyl-specific lectins homologous to the S-type vertebrate lectins. The third group would be constituted by lectins that show homology to vertebrate pentraxins that exhibit lectin-like properties, such as C-reactive protein and serum amyloid P. Finally, there are examples that do not exhibit similarities to any of the aforementioned categories. Moreover, the vast majority of invertebrate lectins described so far cannot yet be placed in one or another group because of the lack of information regarding their primary structure. (See Table 1.) Animal lectins do not express a recombinatorial diversity like that of antibodies, but a limited diversity in recognition capabilities would be accomplished by the occurrence of multiple lectins with distinct specificities, the presence of more than one binding site, specific for different carbohydrates in a single molecule, and by certain "flexibility" of the binding sites that would allow the recognition of a range of structurally related carbohydrates. In order to identify the lectins' "natural" ligands, we have investigated the interactions between those proteins and the putative endogenous or exogenous glycosylated substances or cells that may be relevant to their biological function. Results from these studies, together with information on the biochemical properties of invertebrate and vertebrate lectins, including their structural relationships with other vertebrate recognition molecules, are discussed.

First non-vertebrate member of the myc gene family is seasonally expressed in an invertebrate testis.

We have cloned and characterized the first non-vertebrate member of the myc gene family, pAv-myc, from testes of the Northern sea star, Asterias vulgaris (Echinodermata). We have used an oligonucleotide that is complementary to the virtually 100% conserved vertebrate c-myc box A in the second exon and a cDNA library constructed from spermatogenically active testes. Relatives of this echinoderm existed approximately 100 million years prior to the origin of the earliest known organism for which c-myc sequence is currently available (the trout). Nonetheless, our cDNA encodes a protein with approximately 30% amino acid identity and 46% overall conservation to human c-myc. Regions of substantially higher conservation (63-95%) correspond in order to the transcriptional activation (boxes A, B and C), casein kinase II phosphorylation, nuclear-targeting, basic DNA-binding and oligomerization domains in the second and third exons of human c-myc. Sea star c-myc cDNA detects a 2.7-kb transcript on Northern blots of monthly samples of testicular tissue from field-collected individuals (n = 6-8), indicating peak expression during active spermatogenesis. This is also the first example of seasonal variation in expression of c-myc during spermatogenesis in laboratory or natural populations of any animal. It is intriguing to speculate about the potential oncogenic character of c-myc in this invertebrate, in which tumors have not yet been observed, and about the possibility that c-myc is more widely present in eucaryotes than has been anticipated.

Vegetarian lifestyle and bone mineral density.

The amount and type of dietary protein affect bone mineral loss after the menopause. This observation was substantiated in 10 y of studies by direct photon absorptiometry, four results of which follow. 1) Studies of 1600 women in southwestern Michigan revealed that those who had followed the lactoovovegetarian diet for at least 20 y had only 18% less bone mineral by age 80 whereas closely paired omnivores had 35% less bone mineral. 2) A study of self-selected weighed food intake showed no statistical difference in nutrient intakes but a difference in Ca:P ratio and acid-base formation of diet, each significant to p less than 0.001. 3) When sulfur intake of a fixed diet was increased, the titratable acidity of the urine increased proportionately. 4) Bone mineral densities of 304 older women from the continental United States closely paralleled those from earlier Michigan studies.

Bone mineral mass in adult lacto-ovo-vegetarian and omnivorous males.

Past studies indicate postmenopausal women who eat meat may experience greater bone mineral loss than lacto-ovo-vegetarian women. The present study extends those findings by comparing bone mineral in adult lacto-ovo-vegetarian and omnivorous males. Bone mineral mass was determined by direct photon absorptiometry in 320 lacto-ovo-vegetarian and 320 omnivorous males 20 to 79 yr old. Lacto-ovo-vegetarians were Seventh-day Adventists committed to their diet for at least 20 yr. Measurements were made at a cortical site along the radius. No statistical differences were identified between bone mineral mass in the lacto-ovo-vegetarian and omnivorous males in any decade examined. When contrasted against significant differences between bone mineral mass in postmenopausal omnivores and lacto-ovo-vegetarians, the data presented here may be interpreted as indicating that some factor associated with meat consumption is increasing bone mineral losses in postmenopausal females while having no observable effect in males.

Cortical bone density of adult lacto-ovo-vegetarian and omnivorous women.

Lacto-ovo-vegetarian women fifty to eighty-nine years of age lost 18 per cent bone mineral mass while omnivorous women lost 35 per cent. This study established that this difference could not be explained by a greater bone density in the lacto-ovo-vegetarians during the third, fourth, and fifth decades of life. The possibility of higher sulfur content in the meat-containing diet, the effect of excess phosphorus, and the effect of an acid-ash diet are discussed. From the standpoint of a general survey, comsumption of calcium-containing foods was not appreciably different in the two groups. It is, therefore, concluded that lacto-ovo-vegetarian diet may be beneficial in extended protective health care in terms of defense against, or control of, bone mineral loss in the later years of a woman's life.