Inadequate polyethylene thickness and osteolysis in cementless hip arthroplasty

A matched series Porous Coated Anatomic (PCA), Howmedica, Rutherford, NJ) cementless hip arthroplasties comparing a 26-mm with a 32-mm head were reviewed. The 26-mm head was used in 63 hips of 56 patients (group 1), and the 32-mm head was inserted into 97 hips of 90 patients (group 2). The two groups were matched for age, sex, and primary diagnosis. The postoperative follow-up period ranged from 3 to 6.9 years (mean, 4.2 years) in group 1, compared with 3 to 7.9 years (mean, 4.5 years) for group 2. The mean clinical scores for pain, movement, and function were similar for the two groups. Erosive osteolytic lesions were encountered in 25.7% of the group 2 hips but in none of the group 1 cases. These lesions were not seen before 3 years after surgery and were present in Gruen zone 7 of all involved hips, although in two patients they were also noted in zone 1. Osteolysis was encountered only with the 32-mm head where the outer diameter of the metal backed cup was 52 mm or less. Therefore, inadequate polyethylene thickness, rather than head size, is implicated as the cause of plastic-particle mediated osteolysis.

Ethical evaluation of hypnosis research: a survey of investigators and their institutional review boards

We surveyed hypnosis researchers and Institutional Review Boards (IRBs) with regard to the ethical evaluation of research protocols. Researchers and IRB administrators were independently surveyed within the same institutions. Both objective and free response items were used to address substantive issues such as deception and at-risk populations, as well as practical matters such as paperwork. Parallel questions allowed a point-counterpoint between researchers and IRBs. Overall, the results suggest that IRBs do not treat hypnosis research differently than other types of research. We end with recommendations for facilitating interactions between hypnosis researchers and their IRBs.

Lymphosarcoma with plasmacytoid differentiation in a scarlet macaw (Ara macao)

A lymphosarcoma in a scarlet macaw (Ara macao) affecting periocular structures is described. Microscopically and ultrastructurally, many of the lymphoid cells had plasmacytoid features. Polymerase chain reaction amplification failed to detect exogenous avian retrovirus RAV-1 in the neoplastic mass.

The pathogenesis of osteolysis in two different cementless hip replacements

Wear of ultra-high molecular weight polyethylene has been incriminated in the osteolysis associated with aseptic loosening of hip implants. A variety of different factors can contribute to accelerated patterns of polyethylene wear and subsequent osteolysis. This paper examines the incidence of osteolysis observed in two different well-matched cohorts of cementless total hip arthroplasties. The patterns of osteolysis observed, which are ascribed to the generation of polyethylene debris, are interpreted with reference to the design of the individual prostheses.

Associations of individual genomic heterozygosity, estimated by molecular fingerprinting, and of dam major histocompatibility complex with growth and egg production traits in layer chickens

Growth and egg production data from F2 layer chickens produced from a mating of MHC-heterozygous B15B44 sires to B15B44 and B15B43 dams were analyzed for associations with the level of the individual's genomic heterozygosity and dam MHC. The F1 sires and dams were produced from mating of birds from two genetically distinct, highly inbred lines. Genomic heterozygosity (expressed as composite band frequency, CBF) was estimated based on the average proportion of shared bands of individual birds compared to a composite pool of Hinf I-digested DNA samples from the two inbred lines. Birds from dams of genotype B15B43 had significantly greater BW than progeny from B15B44 dams at 6 wk and thereafter. Dam MHC genotype differences were also significant for number of eggs laid from 20 to 28 wk of age, with B15B43 progeny being superior. Negative regression coefficients at hatch, 32 and 44 wk were observed for the effect of CBF on BW of progeny from B15B43 dams and at hatch and 32 wk from progeny of pooled dam genotypes. Similarly, negative regression coefficients were observed for the association of CBF with number of eggs within progeny from the B15B44 dam MHC genotypes at 20 to 28 wk and total period recorded, and at 28 to 36 wk for progeny from B15B43 dams. The CBF regression coefficients and the differences among progeny based on dam MHC genotypes suggest that individual heterozygosity and MHC genotype may be associated with BW and egg production in chickens.

The accumulation of an E2F-p130 transcriptional repressor distinguishes a G0 cell state from a G1 cell state

Previous studies have demonstrated cell cycle-dependent specificities in the interactions of E2F proteins with Rb family members. We now show that the formation of an E2F-p130 complex is unique to cells in a quiescent, G0 state. The E2F-p130 complex does not reform when cells reenter a proliferative state and cycle through G1. The presence of an E2F-p130 complex in quiescent cells coincides with the E2F-mediated repression of transcription of the E2F1 gene, and we show that the E2F sites in the E2F1 promoter are important as cells enter quiescence but play no apparent role in cycling cells. In addition, the decay of the E2F-p130 complex as cells reenter the cell cycle requires the action of G1 cyclin-dependent kinase activity. We conclude that the accumulation of the E2F-p130 complex in quiescent cells provides a negative control of certain key target genes and defines a functional distinction between these G0 cells and cells that exist transiently in G1.

Poor reproducibility in radiographic grading of femoral cementing technique in total hip arthroplasty

The first study of the reproducibility of a widely accepted grading system for femoral cementation in total hip arthroplasty is reported. Sixty postoperative radiographs were graded on two occasions at least 2 weeks apart by two experienced observers. The test-retest reproducibility rate was 60% for observer 1 and 70% for observer 2. The interobserver reproducibility varied between 60 and 63% for the different assessments. Between 5 and 6% of cases differed by more than one grade between tests. Kappa statistical analysis confirmed that reproducibility was poor in all cases. This cement grading system, even in the hands of experienced observers, has too high a rate of intraobserver and interobserver error to recommend its use.

Mapping functional chicken genes: an alternative approach

Functional genes were selected for linkage analysis mapping using the East Lansing (EL) reference population ¿[Jungle Fowl (JF) x White Leghorn (WL)] x WL¿. The approach used was based on the identification of DNA sequence polymorphisms in the introns of those genes found in JF and WL. Deoxyribonucleic acid sequence analysis revealed single base substitutions in introns of six Type I marker genes: adenylate kinase 1 (AK1), aldolase B (ALDOB), a lysosomal membrane protein gene (LAMP1), vitellogenin 2 (VTG2), apolipoprotein A1 (APOA1), and creatine kinase B (CKB). Transitions or transversions were found in introns of AK1, ALDOB, LAMP1, VTG2, APOA1, and CKB. A transversion in the intron of the JF allele of AK1 generated a unique BspHI cleavage site. The design of polymerase chain reaction (PCR) primers based on the site of base substitution led to the specific amplification of the JF allele in the remaining five genes. A size polymorphism in the PCR production derived from iron response element binding protein (IREBP) distinguished the JF from the WL allele. Linkage analysis of the EL reference population revealed that these candidate genes were located in the following EL linkage groups (E) or chromosomes (Chrom) of the chicken genome: AK1 (E41), VTG2 (E43), APOA1 (E49), CKB (E07), LAMP1 (E01), ALDOB (Chrom Z), and IREBP (Chrom Z). Provided that a base substitution can be found in the parents of the reference population, this PCR-based approach can be used to map any cloned candidate gene. This approach will lead to further information on synteny of the chicken genome with cognate genes of mammalian species.

Use of randomly amplified polymorphic DNA markers for the genetic analysis of relatedness and diversity in chickens and turkeys

A study involving the use of random amplified polymorphic DNA (RAPD) was conducted to evaluate genetic polymorphism and relatedness within and among four chicken breeds: Araucona, Rhode Island Red, White Leghorn, and White Plymouth Rock, and two turkey populations, a long-term randombred and a commercial strain. A total of 60 random primers were used in the RAPD analyses. Forty-two of the 60 primers tested amplified patterns with at least one polymorphic fragment in one or more of the populations. Six of these 42 primers amplified polymorphic fragments in each of the six strains with a within- and between-population average band-sharing frequency of less than one but above zero (P < 0.05). Differences among the six primers for genetic distance (D) among populations were significant (P < 0.05). A consensus dendogram was therefore developed to show the phylogenetic relationships among the populations. As expected, estimates of D between populations were lowest within species and highest between species. The results provide evidence of the applicability of RAPD to determining genetic relatedness within and among different poultry populations and in developing reproducible markers useful in evaluating individual variation in chickens and turkeys.

Revision of failed total hip replacement

The treatment of the patient with a failed total hip replacement has become an ever increasing problem. The incidence and aetiology of failure, and its clinical presentation, are reviewed. The planning and performance of complex revision surgery, including the use of modern bone grafting techniques and specialist implants, are outlined. Postoperative rehabilitation, current research and predictions for the future are also discussed.

Multicentric histiocytosis in young chickens. Gross and light microscopic pathology

During 1991-94, tissue specimens from 262 young chicken carcasses condemned at slaughter contained novel multicentric proliferations of histiocytelike cells. These tissues had been submitted to the USDA FSIS Eastern Laboratory because of grossly enlarged spleens, livers, or kidneys. The spleens were two to three times normal diameter and contained miliary white or yellow 1-3-mm foci. Similar miliary foci were present throughout the enlarged livers and kidneys. Microscopic examination of these tissues revealed discrete circular nodules expanding splenic periarteriolar lymphoid sheaths, hepatic periportal nodules, and discrete perivascular and more diffuse interstitial nodules replacing renal tubules. Nodules also were present in the pancreas, bone marrow, proventriculus, and lung, with more diffuse infiltrates in intestinal lamina propria. The cells composing these nodules contained irregularly oval, folded, or pleomorphic nuclei and relatively abundant eosinophilic cytoplasm. Mitotic figures and pyknotic nuclei were common. These cells were interpreted to be histiocytes (tissue macrophages or dendritic cells) and did not resemble lymphocytes. These proliferating cells also did not resemble the cell population of commonly diagnosed lymphoid neoplasms of young chickens. No intralesional organisms were detected and polymerase chain reaction analysis failed to detect Marek's herpesvirus DNA or leukosis/sarcoma and reticuloendotheliosis proviral DNA.

A restriction enzyme map of the sex-linked late-feathering locus of chickens

A 34-kb restriction endonuclease map of the region associated with an endogenous virus integration site and K, the gene that confers sex-linked late-feathering (LF) in chickens, is presented. Hybridizations of genomic blots of DNA from early-feathering and LF White Leghorns indicated that the region also contains additional repetitive elements upstream from a chicken repetitive (CR1) element. This extended map and the probes described should be useful in identifying the molecular alterations associated with this locus.

Organization of the sex-linked late-feathering haplotype in chickens

Nucleotide sequence analysis of polymerase chain reaction products confirmed that ev21 integrated into one of two large homologous elements on the Z chromosome of late-feathering (LF) White Leghorn chickens. Southern blots of NotI-, NaeI-, KspI- and BamHI-digested DNA from early-feathering (EF) and LF White Leghorns, that had been hybridized with a probe that flanks ev21, indicated a 180 kb duplication of an unoccupied repeat in the LF genotype of White Leghorns. A KspI fragment that carries ev21 was about 32 kb smaller than the KspI fragment found in EF DNA. In the evolution of LF, retroviral insertion into one of two large repeats and a 32 kb deletion may have generated LF.

The Heliospheric Magnetic Field Over the South Polar Region of the Sun

Magnetic field measurements from the Ulysses space mission overthe south polar regions of the sun showed that the structure and properties of the three-dimensional heliosphere were determined by the fast solar wind flow and magnetic fields from the large coronal holes in the polar regions of the sun. This conclusion applies at the current, minimum phase of the 11-year solar activity cycle. Unexpectedly, the radial component of the magnetic field was independent of latitude. The high-latitude magnetic field deviated significantly from the expected Parker geometry, probably because of large amplitude transverse fluctuations. Low-frequency fluctuations had a high level of variance. The rate of occurrence of discontinuities also increased significantly at high latitudes.

Ulysses above the sun's south pole: an introduction

Ulysses has explored the field and particle environment of the sun's polar region. The solar wind speed was fast and nearly constant above -50 degrees latitude. Compositional differences were observed in slow (low-latitude) solar wind and in fast (high-latitude) solar wind. The radial magnetic field did not change with latitude, implying that polar cap magnetic fields are transported toward the equator. The intensity of galactic cosmic rays was nearly independent of latitude. Their access to the polar region is opposed by outward-traveling, large amplitude waves in the magnetic field.

The Rb-related p107 protein can suppress E2F function independently of binding to cyclin A/cdk2

The interaction of the retinoblastoma susceptibility gene product (Rb)-related p107 protein with the E2F transcription factor in S-phase cells facilitates the formation of a multicomponent complex also containing cyclin A and the p33cdk2 kinase. We have created a series of p107 mutants to assess the ability of p107 to inhibit E2F function and the role of the cyclin A/cdk2 complex in this process. We find that p107 mutants that do not bind to E2F also fail to repress E2F-dependent transcription. Moreover, we find that the ability of p107 to suppress E2F-dependent transcription is not dependent on the ability of p107 to associate with cyclin A/cdk2. Finally, an analysis of the ability of the p107 mutant proteins to suppress cell growth suggests that both E2F-dependent and E2F-independent events correlate with this activity.

Ulysses charged particle measurements between 1 and 5 AU from the sun

Proton fluxes obtained by two instruments carried on the ESA/NASA Ulysses spacecraft are reported for the period from launch in October 1990 till Jupiter encounter in February 1992. Proton energy ranges are 24-59, 71-99, 130-320, 320-2100 and > 2100 MeV. The Sun was very active during this period, the events of March 1991 being some of the largest of the solar cycle. The relationship between events on the Sun and the observed proton flux is discussed.

The prevalence of femoral osteolysis associated with components inserted with or without cement in total hip replacements. A retrospective matched-pair series

The prevalence of femoral osteolysis in hips in which a femoral component had been inserted without cement was compared with that in hips with a cemented component, in a retrospective matched-pair study of the results of primary total hip arthroplasties; all patients had received the same type of acetabular component. Forty-one hips in thirty-nine patients who had a Harris-Galante porous-coated total hip prosthesis without cement were matched by age, sex, weight, duration of follow-up, and diagnosis with forty-one hips in thirty-eight patients who had a hybrid total hip reconstruction; the hybrid reconstruction consisted of the same acetabular component and a Precoat femoral component inserted with a so-called third-generation cementing technique. All of the operations were done by the same surgeon, who used the same operative approach and the same course of postoperative rehabilitation. All of the patients were followed for at least four years (mean, six years). Osteolysis developed in twelve (29 percent) of the hips that had a femoral component without cement compared with none of the hips that had a cemented component (p < 0.0002). At the latest follow-up examination, none of the femoral components that had been inserted with cement were loose and none had been revised, while eight (20 percent) of the femoral components that had been inserted without cement were loose and five (12 per cent) had been revised. This retrospective matched-pair study controlled for many of the variables associated with a comparison of the rates of femoral osteolysis in separate series of femoral components fixed with and without cement.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of the zygosity of ev21-K in late-feathering male White Leghorns using the polymerase chain reaction

The dominant sex-linked late-feathering (LF) gene, K, is of commercial importance for sex determination at hatch. Knowledge of the zygosity of sequences associated with K would enable breeders to more efficiently select homozygous grandparent LF males on the maternal side of the standard feather-sex cross because all of their progeny would be LF, whereas only half of the progeny from heterozygous grandparent males would be LF. A specific, polymerase chain reaction (PCR) assay is described that distinguishes White Leghorn K/K males from K/k+ males and obviates the need to raise all LF grandparent males to sexual maturity. Because the Z chromosome of some LF broiler breeders have, in addition to the endogenous virus gene, ev21, the wild type allele, which is termed the unoccupied repeat b (URb), this approach may not be applicable to some broiler lines.

Male-mediated venereal transmission of endogenous avian leukosis virus

Congenital transmission of avian leukosis viruses (ALV) occurs readily through the egg, but transmission of ALV through male seminal fluid is considered to be nonexistent or rare. Progeny from mating endogenous late-feathering (LF), K/k+ males carrying an endogenous virus gene (ev21) with virgin early-feathering (EF) k+/w females were examined for the presence of infectious endogenous virus EV21 using an enzyme-labeled immunoassay for viral capsid antigen p27. All 177 LF chicks expressed EV21, p27, and 171 of 175 EF chicks did not express p27. Blood from the four p27-positive EF chicks revealed only infectious Subgroup E ALV as determined by subgroup-specific virus assays. Southern blot DNA hybridizations, however, ruled out germline integration of EV21 among the four infected EF progeny. Virus EV21 was not shed in albumens of the dams. Moreover, antibodies against ALV Subgroups A and E were not detected in dams 17 wk after the first insemination. Chicks infected with EV21 were found only in the first two of six hatches. Data suggested direct infection of the embryos from viremic semen rather than congenital infection through infected hens. Direct male transmission of EV21 to progeny may be the basis for persistence of refractory lines noted in some ALV eradication programs. Based on the absence of recombinants among 352 progeny, ev21 and K appear to be less than .3 cM apart.

Research note: a rapid method for the detection of the Rous-associated endogenous solitary long terminal repeat, ev15

A rapid method has been developed for the detection of the solitary long terminal repeat ev15, a member of the avian leukosis virus (ALV) family of endogenous viral elements (ev genes) in chickens. Detection is accomplished by a polymerase chain reaction (PCR) assay that can be performed on purified genomic DNA samples or crude preparations of partially purified whole blood lysates. The test discriminates unambiguously between birds that are homozygous ev15-, homozygous ev15+, or heterozygous ev15-/ev15+. The incorporation of a modified touchdown amplification profile significantly improved the specificity of the PCR assay. Small-scale screening of birds from a variety of chicken breeds has revealed that ev15 is present in populations of both egg-strain birds and broilers.

Effect of tumor virus susceptibility alleles on the late-feathering gene K on early growth of White Leghorns

The influence of tumor virus susceptibility (tvb) alleles and the sex-linked, late-feathering-endogenous virus 21 complex (K-ev21) on early growth was observed in progeny from late-feathering (LF) and early-feathering (EF) dams. At 2, 4, 6 and 10 wk of age, homozygous (K/K) males that carried a dominant tvbs1 allele were significantly (P < .05) lighter in total body weight than K/K homozygous endogenous virus (EV) EV21-resistant (tvbr/tvbr) hatchmates. Among heterozygous (K/k+) males, tvbs1 did not significantly influence growth when compared with tvbr/tvbr hatchmates. At 10 wk of age, tvbs1-positive K/w female progeny from LF dams were also significantly lighter than tvbr/tvbr K/w hatchmates. However, among progeny from EF dams no significant within sex differences in body weight were found regardless of their feather or EV susceptibility phenotype. Results indicate that susceptibility to EV21 infection is particularly detrimental to early growth of ev21-K homozygous male and hemizygous female progeny of LF dams.

Some effects of nutrition and management on the fertility of dairy cattle

When 24 cows were classified according to whether they had a better or worse energy status (defined as a plasma beta-hydroxybutyrate level below or above 15 mg/100 ml and a plasma glucose level above or below 55 mg/100 ml) the median interval between calving and the onset of cyclicity was shorter and conception rates were better for the cows with a better energy status at seven and 14 days after calving. This was not repeated when the cows' energy status was assessed as better at either 21 days after calving or at the time of service. In the same group of cows there was a positive correlation between the loss of condition score in early lactation and beta-hydroxybutyrate levels. In a further trial 15 cows fed a silage-based diet during the dry period had better conception rates and greater luteinising hormone responses to buserelin than 14 cows fed a straw-based diet. The straw-fed cows lost more weight before calving and had significantly higher non-esterified fatty acid levels. After calving both groups of cows were fed the same diet but the cows fed straw in the dry period produced less milk and lost less weight than the cows fed silage. Dry cow nutrition affected subsequent fertility and production. The non-esterified fatty acid level in the last week or two of pregnancy is suggested as a practical indication of the level of dry cow nutrition and its probable effect on productivity. No relationships were observed between plasma urea concentrations and the fertility of the cows.