Survivorship of Conserve® Plus monoblock metal-on-metal hip resurfacing sockets: radiographic midterm results of 580 patients.

Resurfacing systems use press-fit, monoblock, cobalt chrome alloy acetabular sockets because of the material's ability to withstand stresses while accommodating a large femoral head. Despite the widespread use of these types of sockets for both hip resurfacing and total hip replacement, there is a paucity of literature assessing the outcomes of these cups in particular. The 10 year survivorship of the Conserve® Plus monoblock acetabular component used in this study was 98.3% with small pelvic osteolytic lesions suspected in only 2.3%. This study highlights the excellent radiographic survivorship profile of the Conserve® Plus socket.

Urinary retinol binding protein in Indo-Asian patients with idiopathic interstitial nephritis.

BACKGROUND: Idiopathic interstitial nephritis (IIN) is common in the UK Indo-Asian population. Lack of systemic involvement and unremarkable urinalysis on stick testing suggest that it may underlie some cases of end-stage renal failure of undetermined cause. If IIN is diagnosed early, prompt initiation of treatment can improve long-term outcome. AIMS: To investigate whether urinary retinol binding protein (RBP) is elevated more commonly than urinary albumin in IIN, and might be useful in the early detection of renal disease in Indo-Asian patients. DESIGN: Preliminary observational study METHODS: We measured urinary RBP and urinary albumin in 19 Indo-Asian patients in whom a renal biopsy had shown IIN, 10 of whom had already been treated with corticosteroids at the time of specimen collection. A further 28 Indo-Asian patients with glomerular disease, and six with normal light-microscopic renal biopsy, were assessed in parallel. RESULTS: Urinary RBP/creatinine ratio (RCR) was elevated in all 19 cases of IIN, compared to 12/19 in whom the albumin/creatinine ratio (ACR) was elevated. Elevated urinary RBP was thus significantly more common than albuminuria in this group (p<0.01). Twelve of the 19 cases also satisfied the criteria for tubular proteinuria. RCR was elevated to >30 times the upper limit of normal in 7/9 who had not previously received corticosteroids, of whom four had normal ACR; none had ACR >5 times the upper limit of normal. DISCUSSION: These data suggest that measurement of urinary RBP should be explored as an adjunct to albuminuria, if screening for renal disease in the Indo-Asian population is contemplated.

A morphologic, biochemical, and biomechanical assessment of short-term effects of osteochondral autograft plug transfer in an animal model.

PURPOSE: The objective of this study was to assess the short-term changes that occur after an osteochondral autograft plug transfer from the femoral trochlea to the medial femoral condyle in a goat model. TYPE OF STUDY: Articular cartilage repair animal study. METHODS: Six adult male goats were used in this study. Two 4.5-mm osteochondral plugs were transferred from the superolateral femoral trochlea to 2 recipient sites in the central portion of the medial femoral condyle for a survival period of 12 weeks. Postmortem, the global effects of the procedure were assessed by gross morphologic inspection and by analyzing the synovial DNA for inflammatory response. The recipient sites were also evaluated histologically and biomechanically. Metabolic activity was determined by (35)SO(4) uptake, and viability was assessed using a live/dead stain and by confocal laser microscopy. RESULTS: There was no evidence of significant gross morphologic or histologic changes in the operative knee as a result of the osteochondral donor or recipient sites. The patella, tibial plateau, and medial meniscus did not show any increased degenerative changes as a result of articulating against the donor or recipient sites of the osteochondral autografts. Analysis of synovial DNA revealed no inflammatory response. Biomechanically, 6- to 7-fold greater stiffness was noted in the cartilage of the transferred plugs compared with the control medial femoral condyle. Furthermore, on histologic examination, the healing subchondral bone interface at the recipient site had increased density. Glycosaminoglycan synthesis as determined by (35)SO(4) uptake was upregulated in the transplanted cartilage plug relative to the contralateral control, showing a repair response at the site of implantation. And finally, confocal microscopy showed 95% viability of the transferred plugs in the medial femoral condyle region. CONCLUSIONS: Our findings demonstrate the ability to successfully transfer an osteochondral autograft plug with maintenance of chondrocyte cellular viability. The transferred cartilage is stiffer than the control medial femoral condyle cartilage, and there is concern regarding the increased trabecular mass in the healing subchondral plate, but these do not result in increased degenerative changes of the opposing articular surfaces in the short term.

The spatial and temporal expression pattern of Nesp and its antisense Nespas, in mid-gestation mouse embryos.

We describe the spatiotemporal expression pattern of Nesp, and its antisense transcript, Nespas. We found non-complementary expression of these two oppositely imprinted transcripts during mouse embryogenesis, in a number of forming embryonic structures. Nesp expression was primarily seen in the somites and vasculature, whereas Nespas was mainly detected in the progress zone, mesenchyme and ectoderm of the limb, and the neural tube.

Injuries of the thoracolumbar spine associated with restraint use in head-on motor vehicle accidents.

Many authors have described spinal and bodily injuries associated with seat belt use. However, most reports have focused primarily on lap seat belts and resultant flexion-distraction injuries. This retrospective chart review studies the relation between the specific type of restraint or air bag and the resultant thoracolumbar spinal injury subtype and associated bodily injuries. The charts of 221 patients who had sustained thoracolumbar fractures in motor vehicle accidents during a 10-year period were reviewed, and 37 patients were identified whose accidents were clearly described as a frontal collision and whose specific form of restraint was recorded. Among the 15 patients who used a shoulder strap and lap belt device (three-point restraint), 12 patients sustained burst fractures (80%) compared with 4 of the 14 patients (28.6%) restrained with lap seat belts alone. Life-threatening intraabdominal injuries occurred in 57.1% of lap-belted victims and in 26.7% of patients who used three-point restraints, and the character of these injuries also differed. No patients in an automobile in which an air bag deployed sustained major associated bodily injuries. Among restrained occupants of head-on motor vehicle accidents who have sustained a thoracolumbar fracture, patients using lap belts are more likely to sustain the classic flexion-distraction injury patterns, whereas patients using three-point restraints may sustain a higher incidence of burst fractures. In addition, three-point restraints are associated with a decreased risk of intraabdominal injury compared with lap seat belts.

An imprinted transcript, antisense to Nesp, adds complexity to the cluster of imprinted genes at the mouse Gnas locus.

The Gnas locus in distal mouse chromosome (Chr) 2 is emerging as a complex genomic region. It contains three imprinted genes in the order Nesp-Gnasxl-Gnas. Gnas encodes a G protein alpha-subunit, and Nesp and Gnasxl encode proteins of unknown function expressed in neuroendocrine tissue. Together, these genes form a single transcription unit because transcripts of Nesp and Gnasxl are alternatively spliced onto exon 2 of Gnas. Nesp and Gnasxl are expressed from opposite parental alleles, with Nesp encoding a maternal-specific transcript and Gnasxl encoding a paternal-specific transcript. We now identify a further imprinted transcript in this cluster. Reverse transcription-PCR analysis of Nesp expression in 15. 5-days-postcoitum embryos carrying only maternal or paternal copies of distal Chr 2 revealed an isoform that is exclusively paternally, rather than maternally, expressed. Strand-specific reverse transcription-PCR showed that this form is an antisense transcript. The existence of a paternally expressed antisense transcript was confirmed by Northern blot analysis. The sequence is contiguous with genomic sequence downstream of Nesp and encompasses Nesp exons 1 and 2 and an intervening intron. We propose that Nespas is an additional control element in the imprinting region of mouse distal Chr 2; it adds further complexity to the Gnas-imprinted gene cluster.

Management of ureteral strictures in renal transplants by antegrade balloon dilatation and temporary internal stenting.

PURPOSE: To evaluate the efficacy of percutaneous balloon dilatation and temporary internal stenting in the treatment of transplant ureteral strictures. METHODS: Nine patients presenting with obstructed renal transplants were treated by antegrade nephrostomy insertion, ureteroplasty, and temporary internal stenting. Following stent removal, patients were divided into two groups for analysis according to whether the obstruction occurred less than (group A) or more than (group B) 3 months following transplantation. RESULTS: All procedures were technically successful. In group A (n = 6), all patients were successfully treated by one or two dilatations with stenting. In group B (n = 3), two patients were successfully treated by one dilatation with stenting. Overall, eight patients (89%) have had their primary or secondary stent removed successfully at a mean interval of 97.5 days after insertion, and remain well at a mean follow-up interval of 22 months. CONCLUSION: Balloon dilatation and temporary internal stenting is a useful method for treating transplant ureteral strictures.

Localisation of the imprinted gene neuronatin, Nnat, confirms and refines the location of a second imprinting region on mouse chromosome 2.

Nine regions on six mouse autosomes are subject to imprinting and uniparental inheritance of any one of these regions results in mice with phenotypic anomalies. So far on distal Chromosome (Chr) 2 there is a unique imprinting region between 2H3 and 2H4 associated with two behavioural disorders and neonatal lethality. A maternally imprinted gene, Nnat, has been identified which is expressed in the nervous system and maps to distal Chr 2. Nnat has been excluded as a candidate for either or both the behavioural phenotypes as it lies proximal to the 2H3-2H4 imprinting region. Here we have mapped Nnat to band 2H1 which is at least 18 Mb proximal to the previously described imprinting region. It maps close to agouti, some alleles of which show differential expression according to parental origin. The localisation of Nnat to band H1 confirms and refines the map location of a second imprinting region on mouse Chr 2.

Cloning and characterization of a sialidase from the murine histocompatibility-2 complex: low levels of mRNA and a single amino acid mutation are responsible for reduced sialidase activity in mice carrying the Neu1a allele.

The Neu1 locus, in the S region of the murine histocompatibility-2 complex, regulates the sialic acid content of several liver lysosomal enzymes. Three alleles, Neu1a, Neu1b, and Neu1c, have been described on the basis of differential sialylation of the enzyme liver acid phosphatase. The Neu1a allele occurs in a small number of mouse strains, e.g., SM/J and is associated with sialidase deficiency. We recently described G9, a sialidase gene in the human major histocompatibility complex (Milner et al. (1997) J. Biol. Chem., 272, 4549-4558), and we now report the characterization of the equivalent gene in mouse. The protein product of the murine G9 gene is 409 amino acids in length and is 83% identical to its human orthologue. Expression of the murine G9 protein in insect cells has confirmed that it is a sialidase, with optimal activity at pH 5. To elucidate the basis of sialidase deficiency in mouse strains carrying the Neu1a allele, we have sequenced the G9 coding regions from mice carrying the three Neu1 alleles and hence defined the amino acid sequence characteristic of each allotype. Of particular interest is a Leu-209 to Ile mutation that is unique to the Neu1a allotype and is associated with reductions in sialidase activity of approximately 68% and approximately 88% compared to the Neu1b and Neu1c allotypes, respectively, when these three protein variants are expressed in insect cells. Additional factors, such as differential expression, may also influence the activities of the Neu1 allotypes in vivo. We have observed that the level of G9 mRNA is substantially reduced in mice carrying the Neu1a allele compared to the Neu1b (85-95% reduction) and Neu1c (approximately 70% reduction) alleles.

Genetic and functional analysis of neuronatin in mice with maternal or paternal duplication of distal Chr 2.

Functional differences between parental genomes are due to differential expression of parental alleles of imprinted genes. Neuronatin (Nnat) is a recently identified paternally expressed imprinted gene that is initially expressed in the rhombomeres and pituitary gland and later more widely in the central and peripheral nervous system mainly in postmitotic and differentiating neuroepithelial cells. Nnat maps to distal chromosome (Chr) 2, which contains an imprinting region that causes morphological abnormalities and early neonatal lethality. More detailed mapping analysis of Nnat showed that it is located between the T26H and T2Wa translocation breakpoints which is, surprisingly, proximal to the reported imprinting region between the T2Wa and T28H translocation breakpoints, suggesting that there may be two distinct imprinting regions on distal chromosome 2. To investigate the potential role of Nnat, we compared normal embryos with those which were PatDp.dist2.T26H (paternal duplication/maternal deficiency of chromosome 2 distal to the translocation breakpoint T26H) and MatDp.dist2.T26H. Expression of Nnat was detected in the PatDp.dist2.T26H embryos, where both copies of Nnat are paternally inherited, and normal embryos but no expression was detected in the MatDp.dist2.T26H embryos with the two maternally inherited copies. The differential expression of Nnat was supported by DNA methylation analysis with the paternally inherited alleles being unmethylated and the maternal alleles fully methylated. Although experimental embryos appeared grossly similar phenotypically in the structures where expression of Nnat was detected, differences in folding of the cerebellum were observed in neonates, and other more subtle developmental or behavioral effects due to gain or loss of Nnat cannot be ruled out.

The mouse chromosome 7 distal imprinting domain maps to G-bands F4/F5.

Mouse Chromosome (Chr) 7 distal to band F3 on the physical map is known to be subject to imprinting, maternal duplication (MatDp) of the region leading to a late embryonic lethality, while paternal duplication (PatDp) causes death in utero before 11.5 dpc. Using a new mouse reciprocal translocation T(7;11)65H to produce MatDp for distal Chr 7, we have mapped the region subject to imprinting more precisely to bands 7F4/F5 on the cytogenetic map. Fluorescence in situ hybridization (FISH) studies on mitotic and meiotic chromosomes of a T65H heterozygote show that the imprinted gene Igf2 is located in the same region. This was confirmed by the finding that embryos with MatDp of bands 7F4/F5 did not express Igf2. We suggest that other members of the imprinted domain containing Igf2, namely Mash2, H19, Ins2, and p57(K1P2), are also located in 7F4/F5 and that some or all of these genes may be responsible for the two imprinting lethalities seen with MatDp and PatDp for this region.

Transplantation immunology.

The success of transplantation is such that it is now the treatment of choice for many of those requiring renal replacement therapy. The use of other solid organs, including liver, pancreas, heart and lung, continues to progress. This article reviews some recent advances in our understanding of the immunological response to alloantigen and xenoantigen.

Thirteen genes (Cebpb, E2f1, Tcf4, Cyp24, Pck1, Acra4, Edn3, Kcnb1, Mc3r, Ntsr, Cd40, Plcg1 and Rcad) that probably lie in the distal imprinting region of mouse chromosome 2 are not monoallelically expressed.

Seven imprinted genes are currently known in the mouse but none have been identified yet in the distal imprinting region of mouse Chromosome (Chr) 2, a region which shows striking linkage conservation with human chromosome 20q13. Both maternal duplication/paternal deficiency and its reciprocal for distal Chr 2 lead to mice with abnormal body shapes and behavioural abnormalities. We have tested a number of candidate genes, that are either likely or known to lie within the distal imprinting region, for monoallelic expression. These included 3 genes (Cebpb, E2f1 and Tcf4) that express transcription factors, 2 genes (Cyp24 and Pck1) that are involved in growth, 5 genes (Acra4, Edn3, Kcnb1, Mc3r and Ntsr) where a defect could lead to neurological and probably behavioural problems, and 3 genes (Cd40, Plcg1 and Rcad) that are less obvious candidates but sequence information was available for designing primers to test their expression. On/off expression of each gene was tested by reverse transcription-polymerase chain reaction (RT-PCR) analysis of RNA extracted from tissues of mice with maternal duplication/paternal deficiency and its reciprocal for the distal region of Chr 2. None of the 13 genes is monoallelically expressed in the appropriate tissues before and shortly after birth which suggests that these genes are not imprinted later in development. This study has narrowed down the search for imprinted genes, and valuable information on which genes have been tested for on/off expression is provided. Since there is considerable evidence of conservation of imprinting between mouse and human, we would predict that the 13 genes are not imprinted in human. Five of the genes: E2f1, Tcf4, Kcnb1, Cd40 and Rcad, have not yet been mapped in human. However, because of the striking linkage conservation observed between mouse Chr 2 and human chromosome 20, we would expect these genes to map on human chromosome 20q13.

Mapping studies of the distal imprinting region of mouse chromosome 2.

The known limits of the distal imprinting region of mouse Chromosome (Chr) 2 are defined by the breakpoints of the translocations T(2;8)2Wa, (T2Wa), and T(2;16)28H, (T28H), in distal H3, and proximal H4 respectively. We have shown that T2Wa and T(2;4)1Go, (T1Go), which has a breakpoint in central H3 map close to a, non-agouti. Ada, adenosine deaminase, lies very near the proximal boundary and Ra, ragged, maps very close to the distal boundary, and is less than 0.2 cM from wasted, wst. From the current data Ada can be taken as the proximal, and Ra as the distal gene marker of the imprinting region on the linkage map. From consensus maps twenty three other markers, including fourteen genes, lie between Ada and Ra, some of which may be useful in investigations of imprinting. Of the markers included in the study reported here, four, Ada, ls, lethal spotting, Ra and wst lie or probably lie within the region but none display any evidence of imprinting. We suggest that recombination frequency is elevated in distal Chr 2, because in none of the crosses could the most closely linked marker be ordered in relation to the translocation breakpoint due to the high frequency of double crossovers.

Adenosine deaminase, Ada, is in mouse chromosome 2H3, and is not allelic with wasted, wst.

The adenosine deaminase locus (Ada) in the mouse has been localized by in situ hybridization to band 2H3. Linkage analysis of backcross data has shown that Ada is 13.8 +/- 2.7 cM from the coat texture mutant, ragged, Ra. From the results of earlier work (Abbott, C. M., et al., Proc. Natl. Acad. Sci. USA 83:693, 1986), it had been suggested that wst was a low-activity allele of Ada, but this cannot be so because Ada and wst have been found to be nonallelic.

Death of mouse embryos that lack a functional gene for glucose phosphate isomerase.

A null allele of the Gpi-1s structural gene, that encodes glucose phosphate isomerase (GPI-1; E.C. 5.3.1.9), arose in a mutation experiment and was designated Gpi-1sa-m1H. The viability of homozygotes has been investigated. No offspring homozygous for the null allele were produced by intercrossing two heterozygotes, so the homozygous condition was presumed to be embryonic lethal. Embryos were produced by crossing Gpi-1sa/null heterozygous females and Gpi-1sb/null heterozygous males. Homozygous null embryos were identified at different stages of development by electrophoresis and staining either for GPI-1 alone or GPI-1 plus phosphoglycerate kinase (PGK) activity. At 6 1/2 and 7 1/2 days post coitum homozygous null embryos were present at approximately the expected 25% frequency (37/165; 22.4% overall) although at 7 1/2 days the homozygous null embryos tended to be small. By 8 1/2 days most homozygous null embryos were developmentally retarded and had not developed significantly further than at 7 1/2 days; some were dead or dying. By 9 1/2 days the homozygous null conceptus was characterised by a small implantation site that contained trophoblast and often a small amount of extraembryonic membrane. Surviving trophoblast tissue was also detectable at 10 1/2 days. Previous studies have shown that oocyte-coded GPI-1 persists only until 5 1/2 or 6 1/2 days. Survival of homozygous null embryos to 7 1/2 or 8 1/2 days and survival of certain extraembryonic tissue to 10 1/2 days suggests that the homozygous null condition may not be cell-lethal although it is certainly embryo-lethal. Mutant cells that are deficient in glycolysis may use the pentose phosphate shunt to bypass the block in glycolysis created by the deficiency of glucose phosphate isomerase, and/or might be rescued by the transport, from the maternal blood, of energy sources other than glucose (such as glutamine). Either strategy may only permit slow cell growth that would not be adequate to support normal embryogenesis. Transport of maternal nutrients would be more efficient to the trophoblast and extraembryonic membranes and this may help to explain why these tissues survive for longer than the embryo itself. The morphological similarity between homozygous nulls and androgenetic conceptuses, where the trophoblast also survives better than the embryo, is discussed.

Parental influences on expression of glucose-6-phosphate dehydrogenase, G6pd, in the mouse; a case of imprinting.

Glucose-6-phosphate dehydrogenase (G6PD) activity was measured in blood from heterozygotes for the normal allele G6pda and the low activity allele G6pda-mlNeu. In adult mice lower activity was found in G6pda/G6pda-mlNeu than in the reciprocal heterozygote G6pda-mlNeu/G6pda (the maternal allele being listed first). Thus, either the paternally derived allele was over-expressed or the maternally derived allele was under-expressed. By contrast, in younger mice the difference in G6PD activity in reciprocal crosses was less marked. The findings are interpreted in terms of differential imprinting of maternally and paternally inherited information. The explanation offered for age related differences is that, as a consequence of imprinting, either the paternal X-chromosome is preferentially reactivated, or cells in which the paternally derived allele is active are at a selective advantage, and proliferate better than those in which the maternally inherited allele is active.