p63 is essential for regenerative proliferation in limb, craniofacial and epithelial development

The p63 gene, a homologue of the tumour-suppressor p53, is highly expressed in the basal or progenitor layers of many epithelial tissues. Here we report that mice homozygous for a disrupted p63 gene have major defects in their limb, craniofacial and epithelial development. p63 is expressed in the ectodermal surfaces of the limb buds, branchial arches and epidermal appendages, which are all sites of reciprocal signalling that direct morphogenetic patterning of the underlying mesoderm. The limb truncations are due to a failure to maintain the apical ectodermal ridge, a stratified epithelium, essential for limb development. The embryonic epidermis of p63-/- mice undergoes an unusual process of non-regenerative differentiation, culminating in a striking absence of all squamous epithelia and their derivatives, including mammary, lacrymal and salivary glands. Taken together, our results indicate that p63 is critical for maintaining the progenitor-cell populations that are necessary to sustain epithelial development and morphogenesis.

p63, a p53 homolog at 3q27-29, encodes multiple products with transactivating, death-inducing, and dominant-negative activities

We describe the cloning of p63, a gene at chromosome 3q27-29 that bears strong homology to the tumor suppressor p53 and to the related gene, p73. p63 was detected in a variety of human and mouse tissues, including proliferating basal cells of epithelial layers in the epidermis, cervix, urothelium, and prostate. Unlike p53, the p63 gene encodes multiple isotypes with remarkably divergent abilities to transactivate p53 reporter genes and induce apoptosis. Importantly, the predominant p63 isotypes in many epithelial tissues lack an acidic N terminus corresponding to the transactivation domain of p53. We demonstrate that these truncated p63 variants can act as dominant-negative agents toward transactivation by p53 and p63, and we suggest the possibility of physiological interactions among members of the p53 family.

Monoallelically expressed gene related to p53 at 1p36, a region frequently deleted in neuroblastoma and other human cancers

We describe a gene encoding p73, a protein that shares considerable homology with the tumor suppressor p53. p73 maps to 1p36, a region frequently deleted in neuroblastoma and other tumors and thought to contain multiple tumor suppressor genes. Our analysis of neuroblastoma cell lines with 1p and p73 loss of heterozygosity failed to detect coding sequence mutations in remaining p73 alleles. However, the demonstration that p73 is monoallelically expressed supports the notion that it is a candidate gene in neuroblastoma. p73 also has the potential to activate p53 target genes and to interact with p53. We propose that the disregulation of p73 contributes to tumorigenesis and that p53-related proteins operate in a network of developmental and cell cycle controls.

Human heart: tagging with MR imaging--a method for noninvasive assessment of myocardial motion

Specified regions of the myocardium can be labeled in magnetic resonance (MR) imaging to serve as markers during contraction. The technique is based on locally perturbing the magnetization of the myocardium with selective radio-frequency (RF) saturation of multiple, thin tag planes during diastole followed by conventional, orthogonal-plane imaging during systole. The technique was implemented on a 0.38-T imager and tested on phantoms and volunteers. In humans, tags could be seen 60-450 msec after RF saturation, thus permitting sampling of the entire contractile phase of the cardiac cycle. Tagged regions appear as hypointense stripes, and their patterns of displacement reflect intervening cardiac motion. In addition to simple translation and rotation, complex motions such as cardiac twist can be demonstrated. The effects of RF pulse angle, relaxation times, and heart rate on depiction of the tagged region are discussed.

p73-deficient mice have neurological, pheromonal and inflammatory defects but lack spontaneous tumours

p73 (ref. 1) has high homology with the tumour suppressor p53 (refs 2-4), as well as with p63, a gene implicated in the maintenance of epithelial stem cells. Despite the localization of the p73 gene to chromosome 1p36.3, a region of frequent aberration in a wide range of human cancers, and the ability of p73 to transactivate p53 target genes, it is unclear whether p73 functions as a tumour suppressor. Here we show that mice functionally deficient for all p73 isoforms exhibit profound defects, including hippocampal dysgenesis, hydrocephalus, chronic infections and inflammation, as well as abnormalities in pheromone sensory pathways. In contrast to p53-deficient mice, however, those lacking p73 show no increased susceptibility to spontaneous tumorigenesis. We report the mechanistic basis of the hippocampal dysgenesis and the loss of pheromone responses, and show that new, potentially dominant-negative, p73 variants are the predominant expression products of this gene in developing and adult tissues. Our data suggest that there is a marked divergence in the physiological functions of the p53 family members, and reveal unique roles for p73 in neurogenesis, sensory pathways and homeostatic control.

Heterozygous germline mutations in the p53 homolog p63 are the cause of EEC syndrome

EEC syndrome is an autosomal dominant disorder characterized by ectrodactyly, ectodermal dysplasia, and facial clefts. We have mapped the genetic defect in several EEC syndrome families to a region of chromosome 3q27 previously implicated in the EEC-like disorder, limb mammary syndrome (LMS). Analysis of the p63 gene, a homolog of p53 located in the critical LMS/EEC interval, revealed heterozygous mutations in nine unrelated EEC families. Eight mutations result in amino acid substitutions that are predicted to abolish the DNA binding capacity of p63. The ninth is a frameshift mutation that affects the p63alpha, but not p63beta and p63gamma isotypes. Transactivation studies with these mutant p63 isotypes provide a molecular explanation for the dominant character of p63 mutations in EEC syndrome.

p63 is a prostate basal cell marker and is required for prostate development

The p53 homologue p63 encodes for different isotypes able to either transactivate p53 reporter genes (TAp63) or act as p53-dominant-negatives (DeltaNp63). p63 is expressed in the basal cells of many epithelial organs and its germline inactivation in the mouse results in agenesis of organs such as skin appendages and the breast. Here, we show that prostate basal cells, but not secretory or neuroendocrine cells, express p63. In addition, prostate basal cells in culture predominantly express the DeltaNp63alpha isotype. In contrast, p63 protein is not detected in human prostate adenocarcinomas. Finally, and most importantly, p63(-/-) mice do not develop the prostate. These results indicate that p63 is required for prostate development and support the hypothesis that basal cells represent and/or include prostate stem cells. Furthermore, our results show that p63 immunohistochemistry may be a valuable tool in the differential diagnosis of benign versus malignant prostatic lesions.

An anti-apoptotic role for the p53 family member, p73, during developmental neuron death

p53 plays an essential pro-apoptotic role, a function thought to be shared with its family members p73 and p63. Here, we show that p73 is primarily present in developing neurons as a truncated isoform whose levels are dramatically decreased when sympathetic neurons apoptose after nerve growth factor (NGF) withdrawal. Increased expression of truncated p73 rescues these neurons from apoptosis induced by NGF withdrawal or p53 overexpression. In p73-/- mice, all isoforms of p73 are deleted and the apoptosis of developing sympathetic neurons is greatly enhanced. Thus, truncated p73 is an essential anti-apoptotic protein in neurons, serving to counteract the pro-apoptotic function of p53.

P63 and P73: P53 mimics, menaces and more

Inactivation of the tumour suppressor p53 is the most common defect in cancer cells. The discovery of its two close relatives, p63 and p73, was therefore both provocative and confounding. Were these new genes tumour suppressors, p53 regulators, or evolutionary spin-offs? Both oncogenic and tumour-suppressor properties have now been attributed to the p53 homologues, perhaps reflecting the complex, often contradictory, protein products encoded by these genes. p63 and p73 are further implicated in many p53-independent pathways, including stem-cell regeneration, neurogenesis and sensory processes.

Association of p63 with proliferative potential in normal and neoplastic human keratinocytes

p63, a recently identified member of the p53 gene family, encodes multiple products with transactivating, death-inducing, and dominant-negative activities. We show that in normal human epidermis, in hair follicles, and in stratified epidermal cultures, p63 protein is principally restricted to cells with high proliferative potential and is absent from the cells that are undergoing terminal differentiation. In normal human epidermis and in hair follicles, basal cells with abundant p63 are interspersed with cells with little or no p63. Whenever p63 mRNA is present, it encodes mainly truncated, potentially dominant-negative isotypes. In squamous cell carcinomas, the number of cells containing p63 and their distribution depends on the degree of anaplasia. In highly differentiated tumors, p63 is confined to a ring of basal-like cells surrounding, but at a distance from, centers of terminal differentiation. In less differentiated tumors, most cells contain p63 and their distribution is chaotic with respect to centers of terminal differentiation. p63 appears to be a valuable diagnostic marker for anaplastic keratinocytes.

Hay-Wells syndrome is caused by heterozygous missense mutations in the SAM domain of p63

Hay-Wells syndrome, also known as ankyloblepharon-ectodermal dysplasia-clefting (AEC) syndrome (OMIM 106260), is a rare autosomal dominant disorder characterized by congenital ectodermal dysplasia, including alopecia, scalp infections, dystrophic nails, hypodontia, ankyloblepharon and cleft lip and/or cleft palate. This constellation of clinical signs is unique, but some overlap can be recognized with other ectodermal dysplasia syndromes, for example ectrodactyly--ectodermal dysplasia--cleft lip/palate (EEC; OMIM 604292), limb--mammary syndrome (LMS; OMIM 603543), acro-dermato-ungual-lacrimal-tooth syndrome (ADULT; OMIM 103285) and recessive cleft lip/palate--ectodermal dysplasia (CLPED1; OMIM 225060). We have recently demonstrated that heterozygous mutations in the p63 gene are the major cause of EEC syndrome. Linkage studies suggest that the related LMS and ADULT syndromes are also caused by mutations in the p63 gene. Thus, it appears that p63 gene mutations have highly pleiotropic effects. We have analysed p63 in AEC syndrome patients and identified missense mutations in eight families. All mutations give rise to amino acid substitutions in the sterile alpha motif (SAM) domain, and are predicted to affect protein--protein interactions. In contrast, the vast majority of the mutations found in EEC syndrome are amino acid substitutions in the DNA-binding domain. Thus, a clear genotype--phenotype correlation can be recognized for EEC and AEC syndromes.

Normal age-related patterns of cellular and fatty bone marrow distribution in the axial skeleton: MR imaging study

Knowledge of age-related distribution patterns of cellular and fatty marrow is critical to the interpretation of magnetic resonance (MR) imaging studies. To determine such patterns, the authors retrospectively evaluated 70 examinations each of the skull, cervical spine, thoracic spine, lumbar spine, pelvis, and proximal femur (420 examinations) in patients without known bone marrow abnormality who ranged in age from 6 months to older than 70 years. Two to four distinct patterns were identified in each anatomic area on spin-echo images obtained with a short repetition time and a short echo time. The relative frequency of the patterns for different age groups is consistent with the known physiologic conversion from cellular to fatty marrow with advancing age. Knowledge of these patterns should help in the interpretation of MR images of the axial skeleton.

Monocryl suture, a new ultra-pliable absorbable monofilament suture

Synthetic absorbable sutures are available as braided constructions or as monofilaments. Braided absorbable sutures are made either from 90:10 poly(glycolide-co-L(-)-lactide), sold by Ethicon, Inc. under the trade name Vicryl, or from polyglycolide, as sold, for instance, by Davis and Geck under the trade name Dexon. There are, however, some concerns with braided sutures that relate to tissue drag and the trauma this may cause, as well as the possible potentiation of infection through the interstices of the braid structure. Absorbable monofilaments, such as the monofilament sutures derived from p-dioxanone homopolymer (PDS II, an Ethicon, Inc. product), or a copolymer of trimethylene carbonate and glycolide (Maxon, a Davis and Geck product), eliminate many of these concerns, but generally monofilaments do not handle as well as braids. This paper describes the research leading to the introduction of Monocryl (poliglecaprone 25) monofilament sutures, based on segmented block copolymers of epsilon-caprolactone and glycolide. Monocryl sutures will be shown to display excellent handling properties, minimal resistance during passage through tissue and excellent tensile properties. These sutures provide an in vivo breaking strength retention of approximately 20-30% after 2 weeks, considered by many to be the critical wound healing period. Absorption data on these sutures are presented; absorption is complete between the 91st and 119th days of implantation, with slight or minimal tissue reaction.

Pelvic floor descent in women: dynamic evaluation with fast MR imaging and cinematic display

The authors present a new method for assessing pelvic prolapse with dynamic fast magnetic resonance (MR) imaging. Twenty-six women with signs and symptoms suggesting pelvic prolapse and 16 control subjects were studied with a series of fast (6-12-second) MR images. Sagittal and coronal images were obtained with graded increase in voluntary pelvic strain, allowing for dynamic display and quantification of the pelvic prolapse process. The distance from the pubococcygeal line was used as an internal reference for measurement of descent in the maximal strain position. With use of control results for normal limit values, prolapse involving the anterior pelvic compartment (cystocele), the middle compartment (vaginal prolapse, uterine prolapse, and enterocele), and the posterior compartment (rectocele) was easily demonstrated. Significant differences between control subjects and patients with prolapse were seen at maximal strain but not in the relaxed state. Quantification of the pelvic descent process with use of fast MR imaging may be of value in surgical planning and postsurgical follow-up.

Mapping brain networks in awake mice using combined optical neural control and fMRI

Behaviors and brain disorders involve neural circuits that are widely distributed in the brain. The ability to map the functional connectivity of distributed circuits, and to assess how this connectivity evolves over time, will be facilitated by methods for characterizing the network impact of activating a specific subcircuit, cell type, or projection pathway. We describe here an approach using high-resolution blood oxygenation level-dependent (BOLD) functional MRI (fMRI) of the awake mouse brain-to measure the distributed BOLD response evoked by optical activation of a local, defined cell class expressing the light-gated ion channel channelrhodopsin-2 (ChR2). The utility of this opto-fMRI approach was explored by identifying known cortical and subcortical targets of pyramidal cells of the primary somatosensory cortex (SI) and by analyzing how the set of regions recruited by optogenetically driven SI activity differs between the awake and anesthetized states. Results showed positive BOLD responses in a distributed network that included secondary somatosensory cortex (SII), primary motor cortex (MI), caudoputamen (CP), and contralateral SI (c-SI). Measures in awake compared with anesthetized mice (0.7% isoflurane) showed significantly increased BOLD response in the local region (SI) and indirectly stimulated regions (SII, MI, CP, and c-SI), as well as increased BOLD signal temporal correlations between pairs of regions. These collective results suggest opto-fMRI can provide a controlled means for characterizing the distributed network downstream of a defined cell class in the awake brain. Opto-fMRI may find use in examining causal links between defined circuit elements in diverse behaviors and pathologies.

Changes in platelet size and count in unstable angina compared to stable angina or non-cardiac chest pain

AIMS

An increase in platelet aggregability is associated with unstable angina and myocardial infarction. Platelet size and activity correlate and mean platelet volume was found to be increased before acute myocardial infarction. We measured the mean platelet volume and platelet count in patients with stable angina, unstable angina and non-cardiac chest pain.

METHODS AND RESULTS

We studied 981 patients (734 men; 247 women) defined clinically as stable angina (n = 688), unstable angina (n = 108) and unstable angina requiring immediate angioplasty (n = 52). After coronary angiography the patients were subdivided into single (n = 269), double (n = 304) and triple-vessel disease (n = 311) and the control group of non-cardiac chest pain (n = 97). There was no significant difference in platelet count between the control group and patients with 1, 2, or 3-vessel disease. However, the platelet size in patients with coronary artery disease was significantly larger (single: 8.7 +/- 1.19 fl; double: 8.7 +/- 1.12 fl; triple-vessel disease: 8.8 +/- 1.18 fl) than the control group (8.2 +/- 0.95 fl) (P < 0.01). Patients with stable angina similarly had no, significant difference in platelet count compared to the control group but did have a significantly increased mean platelet volume (8.7 +/- 1.13; P < 0.01). In contrast, patients with unstable angina had a decreased platelet count (245 +/- 56 x 10/l) compared to either stable angina (262 +/- 62 x 10/l; P < 0.05) or the control group (261 +/- 58 x 10/l; P < 0.05); furthermore, the mean platelet volume (9.4 +/- 1.23 fl) was significantly greater than for stable angina (P < 0.01). Patients with unstable angina requiring immediate PTCA had an even lower platelet count (231 +/- 55 x 10/l) and higher mean platelet volume (10.4 +/- 1.03 fl) (P < 0.01) than the rest of the population with unstable angina.

CONCLUSIONS

In stable angina the platelet count is unchanged compared to patients with normal coronary arteries but the platelet size is increased. However, in unstable angina there is a decrease in platelet count and an even larger increase in platelet size. We interpret this as meaning that unstable angina might be associated or preceded by an increase in platelet destruction rate that is not completely compensated for by an increase in platelet production rate. The large, more reactive platelets might be causally related to an ongoing coronary artery obstruction in unstable angina.

Femoral head avascular necrosis: MR imaging with clinical-pathologic and radionuclide correlation

A retrospective evaluation of magnetic resonance (MR) imaging for the detection of avascular necrosis (AVN) of the femoral head was performed in 49 patients (85 hips) with clinical suspicion of AVN. Positive findings at bone biopsy or evidence on plain radiographs was considered proof of AVN. Absence of clinical symptoms and of radiographic findings for a minimum of 18 months after MR imaging was considered evidence of the absence of AVN. All patients were studied with plain radiography and technetium-99m methylene diphosphonate bone scintigraphy. Five hips had negative MR images, positive findings at bone marrow biopsy, positive bone pressure measurement (BMP), and positive bone scans. A comparison between MR images and bone scans showed MR imaging to be superior, with a sensitivity of 88.8% (vs. 77.5%) and a specificity of 100% (vs. 75%). BMP was the most sensitive (92%) but least specific test (57%).

Histologic and immunophenotypic classification of cervical carcinomas by expression of the p53 homologue p63: a study of 250 cases

Recent studies of the p53 homologue p63 indicate that this gene is preferentially expressed in basal and immature cervical squamous epithelium. This study correlated p63 expression with morphologic phenotype and human papillomavirus (HPV) type in a wide range of cervical neoplasms. Two hundred fifty cases of cervical carcinoma, including squamous cell carcinoma (SCCA; n = 178), adenocarcinoma (ADCA; n = 28), adenosquamous carcinoma (ASCA; n = 8), neuroendocrine carcinoma (NECA; n = 15), and other variant or mixed types (n = 21) were studied. Ninety-seven percent of SCCA, 0% of ADCA, and 0% of SCUC showed strong (>75% v <30%) positivity for p63 (P<.001). p63 sharply distinguished SCCA (p63+) from ADCA (p63-), Large-cell, poorly differentiated carcinomas were distinguished as putative glandular (glassy cell) or squamous (lymphoepithelial-like or spindle cell) types based on p63 staining. Eight (73%) of 11 neuroendocrine tumors tested were chromogranin positive; all showed no or low (<30%) levels of p63 immunostaining. Absence of p63 was also associated with a subset of nonneuroendocrine undifferentiated carcinomas. Transitions from squamous to columnar or undifferentiated morphology coincided with loss of p63 expression. A strong association between HPV 16 and p63 positivity was identified because of the colocalization of both within tumors of squamous phenotype. p63 is a powerful marker for squamous differentiation and, when diffusely expressed, excludes a glandular or neuroendocrine differentiation. p63 may be useful for differentiating pure squamous or glandular from adenosquamous carcinomas, tracking shifts in differentiation within tumors, supporting (by its absence) the diagnosis of neuroendocrine carcinomas, and clarifying the spectrum of poorly differentiated carcinomas lacking either squamous or neuroendocrine differentiation.

Lipid stability and meat colour of beef from pasture- and grain-fed cattle with or without vitamin E supplement

Meat from pasture-fed cattle can have high contents of α-tocopherol and other anti-oxidants originating from naturally occurring compounds present in grasses. However, meat from pasture-fed cattle may have an increased demand for endogenous anti-oxidants because of its high content of polyunsaturated fatty acids, which in turn, may affect its colour and lipid stability. In the work described, we evaluated the effects of pasture-feeding alone and with vitamin E supplementation and compared the findings with those obtained for grain-fed cattle (predominantly sorghum) with and without supplementation. Within each nutritional background, vitamin E supplementation did not alter meat colour or colour stability of fresh or 47-day aged muscle during 7-day aerobic storage. However, both control and supplemented grain-fed product had better meat colour (more redness) compared with meat from grass-fed cattle. These differences in redness between pasture- and grain-fed fresh beef were not apparent after ageing. The treatments did not affect the lipid stability of fresh meat during aerobic storage; however, supplementation reduced (P<0.01) lipid oxidation in grain-fed aged beef compared with pasture-fed aged beef, despite both having similar α-tocopherol contents. Pasture-fed beef had more linolenic acid, less linoleic acid and, overall, was more polyunsaturated than grain-fed beef (P<0.05). In summary, vitamin E supplementation of pasture-fed cattle did not alter muscle tocopherol contents but pasture-fed beef (both control and supplemented) was more susceptible to lipid oxidation following ageing than vitamin E supplemented grain-fed beef.

Carotenoid and retinol concentrations in serum, adipose tissue and liver and carotenoid transport in sheep, goats and cattle

Carotenoid and retinol concentrations were determined in various tissues of sheep, goats and cattle, ruminants known to have widely different levels of pigmentation of their adipose tissues. An objective assessment of fat colour confirmed the whiteness of sheep and goat fat compared with that of cattle. No G-carotene was detected in the serum or fat of sheep and goats, but it was the predominant carotenoid present in the serum and fat of cattle. The major pigment present in serum and fat of sheep and goat was lutein, although its concentration was only 5-10% of that found in cattle. G-carotene was present in the liver of all three species with the highest concentration in cattle. Although lutein was the only carotenoid found in the serum and fat of sheep and goats, it could not be detected in their livers. The concentrations of retinol in serum and fat were similar for each species, but the liver of sheep had about three times the retinol concentration of the liver of goats and cattle. The transport of carotenoids in plasma was investigated. In sheep and goats, the pigments were associated mainly with very low density lipoprotein (VLDL) and low density lipoprotein (LDL), whereas in cattle, high density lipoprotein (HDL) was the major lipoprotein fraction involved.

Stratified mucin-producing intraepithelial lesions of the cervix: adenosquamous or columnar cell neoplasia?

BACKGROUND

Squamous (CIN) and glandular (ACIS) intraepithelial lesions often coexist in the same cervical specimen. However, a less common and little studied variant consists of a stratified epithelium resembling CIN in which conspicuous mucin production is present (Stratified Mucin-producing Intraepithelial LEsions (SMILE). This report describes the phenotypic characteristics of the SMILE, its associated lesions, and its immunophenotype.

METHODS

Eighteen SMILEs were identified by the presence of conspicuous cytoplasmic clearing or vacuoles in lesions otherwise resembling CIN. The morphologic spectrum of SMILEs was detailed; including associated intraepithelial and invasive cervical neoplasms. In addition, selected cases were stained for mucicarmine, markers of squamous cell/reserve cell differentiation (keratin-14 and p63), and proliferative activity (Mib-1).

RESULTS

Stratified neoplastic epithelial cells with a high Mib-1 index and a rounded or lobular contour at the epithelialstromal interface characterized SMILEs. In contrast to CIN, in which mucin droplets are confined to surface cells, mucin was present throughout the epithelium, varying from indistinct cytoplasmic clearing to discrete vacuoles. SMILEs were distinguished from benign metaplasia by nuclear hyperchromasia and a high Mib-1 index. All but three coexisted with either a squamous (CIN) or glandular (ACIS) precursor lesion. Nine of nine coexisting invasive carcinomas contained glandular, adenosquamous differentiation, or both. SMILEs stained negative for keratin-14 and variably for p63. When present, staining with p63 was confined to basal areas of SMILEs and was absent in areas of columnar differentiation.

CONCLUSIONS

SMILEs are unusual cervical intraepithelial lesions best classified as variants of endocervical columnar cell neoplasia based on immunophenotype. The distribution and immunophenotype of SMILEs are consistent with a neoplasm arising in reserve cells in the transformation zone. The coexistence of a wide spectrum of intraepithelial and invasive cell phenotypes suggests that SMILEs are a marker for phenotypic instability, emphasizing the importance of identifying SMILEs and ensuring a complete examination of specimens containing this unusual precursor lesion.

Analysis of temporal wear patterns of porous-coated acetabular components: distinguishing between true wear and so-called bedding-in

BACKGROUND

Standard radiographic assessment of penetration by the femoral head into a polyethylene liner does not enable clinicians to distinguish between the two processes that cause movement of the head: true wear (the removal of polyethylene particles) and so-called bedding-in (other factors, such as creep and settling-in of the liner). By analyzing radiographs made over time, researchers can distinguish true wear from the bedding-in process. The purpose of the current study was to compare the wear performance of the initial modular acetabular cup design (so-called first-generation components) of three different manufacturers with that of a so-called second-generation component made by one of the manufacturers.

METHODS

A two-dimensional computerized radiographic method was used to analyze 1300 radiographs of 315 hips that were followed for 3.0 to 10.5 years. Temporal penetration by the head in the three groups of first-generation cups was compared with penetration in the group of second-generation cups. Multiple linear regression analysis was used to model penetration-versus-time data as a line for each group. The slope of each regression line indicated the true rate of wear, and the intercept of the regression line indicated the amount of bedding-in.

RESULTS

Modifications in the design of the second-generation components, including thicker polyethylene and an improved locking mechanism, led to a decrease in the mean penetration by the head; however, the second-generation component did not have a lower true rate of wear than two of the first-generation components. Rather, the decreased penetration by the head into the second-generation component resulted from decreased bedding-in of the liner.

CONCLUSIONS

These findings and this technique of analysis are clinically relevant to surgeons who evaluate polyethylene wear radiographically. First, penetration by the head in the early postoperative years might not be due entirely to abrasive wear of the polyethylene liner but, rather, to a change in the position of the head resulting from the bedding-in process. The inclusion of bedding-in in calculations of wear artificially inflates the rate of wear and may result in a misrepresentation of the potential risk of wear-related complications. This is especially true with regard to comparisons of different designs of modular cups, in which conformity and tolerances between the polyethylene liner and the metal shell can vary greatly. Second, analysis of penetration by the head at multiple time-intervals can be used to distinguish true polyethylene wear from the bedding-in process. Such an analysis allows more accurate determination of the true rates of wear of different designs of modular cups and, therefore, of potential wear-related complications.

Effect of vitamin E supplementation on α-tocopherol and β-carotene concentrations in tissues from pasture- and grain-fed cattle

The effects of dietary vitamin E supplementation of grain-fed cattle on lipid oxidation and meat colour have been extensively investigated, but little attention has been given to pasture-fed cattle where meat is likely to contain naturally high amounts of α-tocopherol and carotenoids. In the work described, we evaluated the effects of pasture-feeding alone and with vitamin E supplementation on tissue levels of anti-oxidants and compared the findings with those obtained for grain-fed cattle with and without supplementation. Sorghum was the major component of the grained-based ration. α-Tocopherol concentrations in plasma, muscle and fat tissues of pasture-fed cattle were not affected by vitamin E supplementation (2500 IU/head/day for 132 days prior to slaughter) while those of grain-fed cattle increased significantly. The α-tocopherol concentrations in the supplemented grain-fed cattle were similar in muscle and liver to pasture-fed animals but were lower in their fat (P<0.05). The major carotenoid present in all tissues studied from pasture-fed was β-carotene and its contents in plasma, liver, fat and muscles were decreased (P<0.05) by supplementation with vitamin E. Carotenoids were essentially absent in grain-fed cattle except for small amounts in liver. The implication of this study for the meat industry is that cattle grazed on good pasture can achieve concentrations of α-tocopherol in muscles and other tissues at least as high as those obtained by supra-nutritional supplementation of grain-fed cattle with vitamin E. However, α-tocopherol supplementation of pasture-fed cattle reduced tissue concentrations of β-carotene, which would reduce carcase fat yellowness and make pasture-fed cattle more acceptable to some Asian markets.

Expression of the p53 homologue p63 in early cervical neoplasia

BACKGROUND

p63, a homologue of the tumor suppressor gene p53, is expressed in embryonic, adult murine, and human basal squamous epithelium and encodes both transactivating and dominant negative transcript isoforms. Mouse embryos functionally deficient in p63 fail to replenish basal squamous epithelial cells, resulting in multiple defects that include absent genital squamous epithelium. This study investigated the expression of p63 in the human cervical transformation zone and early cervical neoplasia.

METHODS

Tissue localization of p63 was determined by immunohistochemistry in a wide range of epithelia. A correlation was also made between p63 expression and squamous basal cell (keratin 14), endocervical columnar cell (mucicarmine), and cell-cycle specific (Ki-67) markers.

RESULTS

p63 expression by immunostaining delineated basal and parabasal cells of maturing ectocervical squamous mucosa, squamous metaplasia in the cervix, and basal and subcolumnar cells of the cervical transformation zone. In atrophic epithelia immunostaining for p63 was present in all cell strata. In early cervical neoplasia, p63 expression was inversely correlated with both squamous cell maturation and nonsquamous differentiation in CIN. This biomarker also identified basal cells in a subset of preinvasive cervical neoplasms with endocervical cell differentiation that were bcl-2 and keratin 14 negative.

CONCLUSIONS

In the lower female genital tract, p63 is preferentially expressed in immature cells of squamous lineage and is not linked to cell proliferation. The broader range of p63 expression relevant to keratin 14 and bcl-2 indicates that p63 may identify additional subsets of benign and neoplastic epithelial basal cells in the cervical transformation zone and may be useful in studying cell differentiation in the early stages of neoplastic change in this region.