Upregulated MYC expression and p53 mutations may contribute to the oncogenesis of canine Meibomian gland carcinomas.

Sebaceous carcinomas of the human ocular adnexa commonly exhibit pagetoid spread, mutations in tumor-suppressor genes, and protooncogene copy number gain. Sebaceous carcinomas are rarely reported in other species, and while the Meibomian gland (MG) represents the most common ocular adnexal structure of the canine eyelid to develop neoplasia, most are clinically and histologically benign. The objective of this study was to compare molecular features of canine MG carcinomas and adenomas. Two retrospectively identified MG carcinomas were subject to immunohistochemistry and qPCR. When compared with normal glands, MYC was upregulated in benign and malignant MG neoplasms. Aberrant p53 expression was restricted to the nuclei of intraepithelial neoplastic cells in MG carcinomas. Adipophilin expression was diminished in MG neoplasms compared with the normal MG. Our findings, if confirmed in a larger cohort of cases, could suggest that MG oncogenesis in a dog may exhibit similar molecular features as their human counterparts.

Modeling and predicting osteoarthritis progression: data from the osteoarthritis initiative.

OBJECTIVE: The goal of this study was to model the longitudinal progression of knee osteoarthritis (OA) and build a prognostic tool that uses data collected in 1 year to predict disease progression over 8 years. DESIGN: To model OA progression, we used a mixed-effects mixture model and 8-year data from the Osteoarthritis Initiative (OAI)-specifically, joint space width measurements from X-rays and pain scores from the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire. We included 1243 subjects who at enrollment were classified as being at high risk of developing OA based on age, body mass index (BMI), and medical and occupational histories. After clustering subjects based on radiographic and pain progression, we used clinical variables collected within the first year to build least absolute shrinkage and selection (LASSO) regression models for predicting the probabilities of belonging to each cluster. Areas under the receiver operating characteristic curve (AUC) represent predictive performance on held-out data. RESULTS: Based on joint space narrowing, subjects clustered as progressing or non-progressing. Based on pain scores, they clustered as stable, improving, or worsening. Radiographic progression could be predicted with high accuracy (AUC = .86) using data from two visits spanning 1 year, whereas pain progression could be predicted with high accuracy (AUC = .95) using data from a single visit. Joint space narrowing and pain progression were not associated. CONCLUSION: Statistical models for characterizing and predicting OA progression promise to improve clinical trial design and OA prevention efforts in the future.

Identification of actin filaments in the rhabdomeral microvilli of Drosophila photoreceptors.

The phototransductive microvilli of arthropod photoreceptors each contain an axial cytoskeleton. The present study shows that actin filaments are a component of this cytoskeleton in Drosophila. Firstly, actin was detected in the rhabdomeral microvilli and in the subrhabdomeral cytoplasm by immunogold labeling with antiactin. Secondly, the rhabdomeres were labeled with phalloidin, indicating the presence of filamentous actin. Finally, the actin filaments were decorated with myosin subfragment-1. The characteristic arrowhead complex formed by subfragment-1 decoration points towards the base of the microvilli, so that the fast growing end of each filament is at the distal end of the microvillus, where it is embedded in a detergent-resistant cap. Each microvillus contains more than one actin filament. Decorated filaments extend the entire length of each microvillus and project into the subrhabdomeral cytoplasm. This organization is comparable to that of the actin filaments in intestinal brush border microvilli. Similar observations were made with the photoreceptor microvilli of the crayfish, Procambarus. Our results provide an indication as to how any myosin that is associated with the rhabdomeres might function.

Differential localizations of and requirements for the two Drosophila ninaC kinase/myosins in photoreceptor cells.

The ninaC gene encodes two retinal specific proteins (p132 and p174) consisting of a protein kinase domain joined to a domain homologous to the head region of the myosin heavy chain. The putative myosin domain of p174 is linked at the COOH-terminus to a tail which has some similarities to myosin-I tails. In the current report, we demonstrate that the ninaC mutation results in light- and age-dependent retinal degeneration. We also show that ninaC flies display an electrophysiological phenotype before any discernible retinal degeneration indicating that the electrophysiological defect is the primary effect of the mutation. This suggests that ninaC has a role in phototransduction and that the retinal degeneration is a secondary effect resulting from the defect in phototransduction. To examine the requirements for the individual ninaC isoforms, mutant alleles were generated which express only p132 or p174. Elimination of p174 resulted in a ninaC phenotype as strong as the null allele; however, elimination of p132 had little if any effect. As a first step in investigating the basis for the difference in requirements for p174 and p132 we performed immuno-localization at the electron microscopic level and found that the two isoforms display different subcellular distributions in the photoreceptor cells. The p132 protein is restricted primarily to the cytoplasm and p174 to the rhabdomeres, the microvillar structure which is the site of action of many of the steps in phototransduction. This suggests that the p174 myosin-I type tail is the domain responsible for association with the rhabdomeres and that the substrate for the p174 putative kinase may be a rhabdomeric protein important in photo-transduction.

Class VI unconventional myosin is required for spermatogenesis in Drosophila.

We have identified partial loss of function mutations in class VI unconventional myosin, 95F myosin, which results in male sterility. During spermatogenesis the germ line precursor cells undergo mitosis and meiosis to form a bundle of 64 spermatids. The spermatids remain interconnected by cytoplasmic bridges until individualization. The process of individualization involves the formation of a complex of cytoskeletal proteins and membrane, the individualization complex (IC), around the spermatid nuclei. This complex traverses the length of each spermatid resolving the shared membrane into a single membrane enclosing each spermatid. We have determined that 95F myosin is a component of the IC whose function is essential for individualization. In wild-type testes, 95F myosin localizes to the leading edge of the IC. Two independent mutations in 95F myosin reduce the amount of 95F myosin in only a subset of tissues, including the testes. This reduction of 95F myosin causes male sterility as a result of defects in spermatid individualization. Germ line transformation with the 95F myosin heavy chain cDNA rescues the male sterility phenotype. IC movement is aberrant in these 95F myosin mutants, indicating a critical role for 95F myosin in IC movement. This report is the first identification of a component of the IC other than actin. We propose that 95F myosin is a motor that participates in membrane reorganization during individualization.

In prostate cancer needle biopsies, detections of PTEN loss by fluorescence in situ hybridization (FISH) and by immunohistochemistry (IHC) are concordant and show consistent association with upgrading.

The prognostic value of phosphatase and tensin homolog (PTEN) loss in prostate cancer has primarily been evaluated by either fluorescence in situ hybridization (FISH) or immunohistochemistry (IHC). Previously, we found that PTEN loss by IHC was associated with increased risk of upgrading from biopsy (Gleason 3 + 3) to prostatectomy (Gleason 7+). Now, using an evaluable subset of 111 patients with adjacent biopsy sections, we analyzed the association between PTEN deletion in cancer and the odds of upgrading by a highly sensitive and specific four-color FISH assay. We also compared the concordance of PTEN loss by IHC and PTEN deletion by FISH. PTEN deletion was found in 27 % (12/45) of upgraded cases compared with 11 % (7/66) of controls (P = 0.03). Cancers with PTEN deletions were more likely to be upgraded than those without deletions (adjusting for age odds ratio = 3.40, 95 % confidence interval 1.14-10.11). With respect to concordance, of 93 biopsies with PTEN protein detected by IHC, 89 (96 %) had no PTEN deletion by FISH, and of 18 biopsies without PTEN protein by IHC, 15 had homozygous or hemizygous PTEN deletion by FISH. Only 4 biopsies of the 93 (4 %) with PTEN protein intact had PTEN deletion by FISH. When the regions of uncertainty in these biopsies were systematically studied by FISH, intra-tumoral variation of PTEN deletion was found, which could account for variation in immunoreactivity. Thus, FISH provides a different approach to determining PTEN loss when IHC is uncertain. Both FISH and IHC are concordant, showing consistent positive associations between PTEN loss and upgrading.

Expression of the DNA-PK binding protein E4-34K fails to confer radiation sensitivity to mammalian cells.

PURPOSE: The adenovirus E4orf6 34 kDa protein (E4-34k) is known to disrupt V(D)J recombination as a result of its interaction with the catalytic subunit of cellular DNA-dependent protein kinase (DNA-PK(cs)), a major participant in the repair of DNA double-strand breaks (DSB). Previous studies have shown that cells with disrupted DSB repair and V(D)J recombination due to attenuation of DNA-PK(cs) activity exhibit a radiation-sensitive phenotype. It is not known at present whether the E4-34k protein can also modify cellular response to ionizing radiation. In an attempt to develop a novel gene therapy strategy to modify cellular radiation response, we sought to determine if expression of the adenovirus E4-34k protein resulted in sensitization to clinically relevant doses of ionizing radiation. MATERIALS AND METHODS: In order to minimize potential bias resulting from selection procedures, we performed clonogenic survival assays on DU 145 prostate cancer cells, RKO colorectal cancer cells and 293 kidney cells following transient transfection of E4-34k- and/or E1B-55k-expressing plasmids. Western blots and immunohistochemical analyses were used to demonstrate E4-34k expression within transfected cells. FACS sorting was carried out to enrich cells transfected with a plasmid that expresses both E4-34k and enhanced green fluorescent protein. RESULTS: It is shown that E4-34k expression does not affect cellular radiosensitivity of transiently transfected populations of either DU 145 prostate or RKO colon cancer cell lines. Similarly, the radiosensitivity of human embryonic kidney 293 cells, which constitutively express the E1B-55k protein, was also unaffected. The radiosensitivity of DU 145 cells co-transfected with E4-34k- and E1-55K-expressing plasmids was unchanged, suggesting that the adenovirus E1B-55k protein does not augment any effects E4-34k might have on DNA-PK(cs) activity. CONCLUSIONS: The lack of radiosensitization by E4-34k expression is quite intriguing as it is known that E4-34k interaction with DNA-PK(cs) causes disruption of V(D)J recombination, a process dependent on DSB rejoining. These data suggest that for future studies, preferential targeting of DNA-PK(cs) DSB activity will be required to influence cellular radiosensitivity.

False recognition occurs more frequently during source identification than during old-new recognition.

A number of recent reports have investigated false memories using variants of the Deese-Roediger-McDermott (DRM) paradigm. Because these false memories have been difficult to eliminate, this study investigated whether false recognition could be reduced by incorporating source-monitoring criteria into decision processes. Making claims about the manner in which items were learned should require more careful scrutiny of memories, and therefore false recognition should be minimized with source instructions as compared with old-new recognition instructions. In 3 experiments that varied the combination of sources, false recognition was increased rather than reduced by applying source-monitoring processes. The theoretical implications of these counterintuitive results are discussed in terms of the old-new detection component of source judgments.

Toward specifying the attentional demands of recognition memory.

Previous studies have concluded that recognition memory is immune to disruption from divided attention and therefore is a relatively automatic process (A. Baddeley, V. Lewis, M. Eldridge, & N. Thomson, 1984; F. I. M. Craik, R. Govoni, M. Naveh-Benjamin, & N. D. Anderson, 1996). Because costs have been found on the concurrent task used to divide attention, recognition may nevertheless require some attentional resources (M. Naveh-Benjamin, F. I. M. Craik, J. Guez, & H. Dori, 1998). The present authors used attention-demanding concurrent tasks to demonstrate significant costs on both the concurrent task and recognition memory performance. Decrements in recognition accuracy were found for classes of items that were studied deeply but not for more shallowly learned materials. The present findings suggest that recognition processes can require significant attentional resources when tested under the appropriate conditions. The results are discussed in terms of the requirements both at encoding and at test that are needed to observe dual-task decrements to recognition accuracy.

Event-based prospective memory and executive control of working memory.

In 5 experiments, the character of concurrent cognitive processing was manipulated during an event-based prospective memory task. High- and low-load conditions that differed only in the difficulty of the concurrent task were tested in each experiment. In Experiments 1 and 2, attention-demanding tasks from the literature on executive control produced decrements in prospective memory. In Experiment 3, attention was divided by different loads of articulatory suppression that did not ultimately lead to decrements in prospective memory. A high-load manipulation of a visuospatial task requiring performance monitoring resulted in worse prospective memory in Experiment 4, whereas in Experiment 5 a visuospatial task with little monitoring did not. Results are discussed in terms of executive functions, such as planning and monitoring, that appear to be critical to successful event-based prospective memory.

A decrement-to-familiarity interpretation of the revelation effect from forced-choice tests of recognition memory.

In the revelation effect, the probability of labeling a target or a lure as "old" on item recognition tests increases if just prior to their recognition judgment, participants first identify a disguised version of the test item. The same occurs with interpolated tasks that occur just prior to a recognition judgment if the task shares constituents with the test items. One explanation of this test bias is an increased feeling of familiarity that comes from the identification stage preceding the recognition judgment (e.g., D. C. LeCompte, 1995; C. R. Lou, 1993). This study's finding in 4 experiments that 2-alternative forced-choice recognition either yields no effects of revelation or an "antirevelation" effect, even when both items were studied or nonstudied, is incongruent with this explanation. The authors argue that revelation decrements familiarity, and this results in a more liberal criterion shift. They also argue that their theory is more consistent with previous empirical data.

The properties of retention intervals and their affect on retaining prospective memories.

Five experiments were conducted to explore how the character of the retention interval affected event-based prospective memory. According to the canons of retrospective memory, prospective performance should have been worse with increasing delays between intention formation and the time it was appropriate to complete an action. That result did not occur. Rather, prospective memory was better with increasing retention intervals in Experiments 1A, 1B, and 3. In manipulating the nature of the retention interval, the authors found that there were independent contributions of retention interval length and the number of intervening activities, with more activities leading to better prospective memory (Experiments 2 and 3). The identical retention intervals did not improve retrospective memory in Experiment 4. Theoretical explanations for these dissociations between prospective and retrospective memory are considered.

Remember-know judgments can depend on how memory is tested.

Remember-know judgments reflect the subjective state of awareness that accompanies episodic memory retrieval. We tested an old-new recognition condition, an old-new recognition followed by remember-know judgment condition, and a simultaneous remember-know-new judgment condition. These three conditions were tested for both a short (1-sec) and a long (4.5-sec) study duration. Reassuringly, results from the first two conditions did not differ from each other. Results from the third condition, however, differed from those in the first two conditions at both long and short study durations. Simultaneous consideration of all three alternatives resulted in a markedly liberal response bias, both in recognition detection and in the ascriptions of remember and know judgments. Discussion of the results is framed in terms of the single-process signal detection models that have been proposed to account for these subjective states of awareness.

Infected joint replacements in HIV-positive patients with haemophilia.

Joint replacement in HIV-positive patients remains uncommon, with most experience gained in patients with haemophilia. We analysed retrospectively the outcome of 102 replacement arthroplasties in 73 HIV-positive patients from eight specialist haemophilia centres. Of these, 91 were primary procedures. The mean age of the patients at surgery was 39 years, and the median follow-up was for five years. The overall rate of deep sepsis was 18.7% for primary procedures and 36.3% for revisions. This is a much higher rate of infection than that seen in normal populations. A total of 44% of infections resolved fully after medical and/or surgical treatment. The benefits of arthroplasty in haemophilic patients are well established but the rates of complications are high. As this large study has demonstrated, high rates of infection occur, but survivorship analysis strongly suggests that most patients already diagnosed with HIV infection at the time of surgery should derive many years of symptomatic relief after a successful joint replacement. Careful counselling and education of both patients and healthcare workers before operation are therefore essential.

Important landmarks of the orofacial complex.

Hard-tissue and soft-tissue landmarks of the face and oral cavity are introduced. Definitions for anatomic structures are listed, and figures to aid clinical examination are provided. Relevance of these landmarks to examination, diagnosis, and function is made.

Fluoride release from orthodontic adhesives.

Two commercial orthodontic adhesives containing fluoride were evaluated in vitro for fluoride release. Fluoride release is critical in preventing both decalcification around orthodontic brackets and the formation of white spot lesions. A paste-type adhesive composite resin and a glass ionomer luting agent were compared to a glass ionomer restorative material to determine fluoride release. The composite resin adhesive released minimal fluoride for only three days and then ceased. The glass ionomer adhesive released fluoride at a similar rate to the glass ionomer restorative material with fluoride release still evident at three months.

Evaluation of a phosphonate BIS-GMA resin as a bracket adhesive.

Panavia is a modified phosphate ester of dimethacrylate that purportedly forms a strong bond to tooth structure and to metals. The ability of this adhesive to bond orthodontic brackets to enamel was compared to the bond strengths of a no-mix bracket adhesive and a paste/paste autopolymerizing composite resin. Panavia did not form a bond as strong as that achieved by the bracket adhesive but was stronger than the composite resin.

The program directors' perspective on the goals and objectives of advanced general dentistry training.

In September of 1991, all postgraduate general dentistry (PGD) program directors (Advanced Education in General Dentistry [AEGD] and General Practice Residency [GPR] directors [n = 325]) were surveyed to ascertain their opinions of the ideal goals and objectives of PGD programs. The response rate was 81.5 percent (n = 265). The directors rated the relative importance of various PGD program goals and objectives. The average of all the items rated was 3.4 on a scale ranging from 1 = unimportant to 4 = very important. The respondents identified several clinical and didactic subject areas that they considered very important including; infection control, CPR, dental and medical emergencies, diagnosing dentoalveolar trauma, diagnosing oral pathology, and assessment and treatment of patients with medical conditions. They also identified several training areas which were beyond the scope of a PGD program, e.g., research techniques, pediatric sedation, and selected advanced clinical procedures in dentistry (implantology and orthodontics) which require a long time to complete. In general, there was substantial agreement among the directors of different program types and sites as to the relative importance of various program goals. The largest differences were found among directors of programs from different sites, e.g., hospitals versus dental schools as opposed to directors from different program types, e.g., GPR versus AEGD. There is now a need to determine the relationship of these identified idealized goals and differences to program outcomes for the graduates of PGDs.

Effects of reducing senior clinical requirements.

This study investigated the effects of reducing dental clinical requirements. Twenty-seven senior students participated in a modified system in which requirements were reduced to essential experiences, points were awarded for all procedures completed, and a total point requirement was created to ensure comprehensive care. The remaining seniors (N = 97), who operated under the conventional requirement system, served as controls. No significant differences were found between the groups in daily clinic grades, comprehensive examination performance, final senior-year grade point average, or number of procedures completed. A year-end questionnaire on stress and anxiety indicated that the experimental group perceived less stress and anxiety, were significantly more positive about their performance evaluations, and perceived significantly less pressure to complete procedures.

Linking postdoctoral general dentistry programs with community-based clinical care settings.

This article presents the results of a small workgroup convened by the American Association of Dental Schools to examine experiences related to establishing and conducting dental education programs that have significant affiliations with community-based clinical care settings. The workgroup meeting is a component of the association's effort to identify and promote innovative and non-traditional methods by which the number of postdoctoral general dentistry (PGD) positions can be increased to meet current demand for PGD education. The participants identified factors and conditions believed to be critical to successful program linkages. The information should be helpful to others as they consider opportunities to establish PGD programs or increase their number of PGD training positions.