Context Matters: Social Psychological Factors That Underlie Academic Performance across Seven Institutions.

To enhance equity and diversity in undergraduate biology, recent research in biology education focuses on best practices that reduce learning barriers for all students and improve academic performance. However, the majority of current research into student experiences in introductory biology takes place at large, predominantly White institutions. To foster contextual knowledge in biology education research, we harnessed data from a large research coordination network to examine the extent of academic performance gaps based on demographic status across institutional contexts and how two psychological factors, test anxiety and ethnicity stigma consciousness, may mediate performance in introductory biology. We used data from seven institutions across three institution types: 2-year community colleges, 4-year inclusive institutions (based on admissions selectivity; hereafter, inclusive), and 4-year selective institutions (hereafter, selective). In our sample, we did not observe binary gender gaps across institutional contexts, but found that performance gaps based on underrepresented minority status were evident at inclusive and selective 4-year institutions, but not at community colleges. Differences in social psychological factors and their impacts on academic performance varied substantially across institutional contexts. Our findings demonstrate that institutional context can play an important role in the mechanisms underlying performance gaps.

Patterning small-molecule biocapture surfaces: microcontact insertion printing vs. photolithography.

Chemical patterns prepared by self-assembly, combined with soft lithography or photolithography, are directly compared. Pattern fidelity can be controlled in both cases but patterning at the low densities necessary for small-molecule probe capture of large biomolecule targets is better accomplished using microcontact insertion printing (µCIP). Surfaces patterned by µCIP are used to capture biomolecule binding partners for the small molecules dopamine and biotin.

DICE (dexamethasone, ifosfamide, cisplatin, etoposide) infusional chemotherapy for refractory or relapsed non-Hodgkin's lymphoma (NHL).

Continuous exposure to naturally-derived chemotherapy agents such as etoposide may theoretically override drug resistance due to overexpression of the multidrug resistance gene product, p-glycoprotein. Dexamethasone in high dose may have a similar overriding effect. Data also suggest that ifosfamide both by continuous infusion and when combined with a platinum compound may be more effective. Forty-four chemotherapy-refractory/relapsed lymphoma patients received the DICE infusional regimen. The programme consisted of dexamethasone 40 mg i.v. daily for 4 days, ifosfamide 1500 mg mixed with equal dosing of mesna continuously infused i.v. daily for 4 days, cisplatin 25 mg i.v. each day for 4 days and etoposide 150 mg continuously infused i.v. daily for 4 days, all administered every 3 weeks. Doses of ifosfamide and etoposide were escalated by 250 mg and 25 mg, respectively, based on patient tolerance, usually lack of myelosuppression. Special hydration was not required. G-CSF support was provided to patients as required. All patients had disease that had relapsed from or was resistant to CHOP or a similar anthracycline-containing combination regimen. A majority had previously received at least two regimens and 27% had received three or more. Of 44 patients, 32 (73%) achieved a significant response consisting of 18 complete remissions (CR) (41%) and 14 (32%) partial remissions (PR). There were 81% objective responses in large cell lymphoma comprised of 50% CR and 31% PR. Previous response to chemotherapy predicted response to DICE: 83% (25/30) of prior responders vs 50% (7/14) of non-responders had a response to the treatment regimen (p = 0.031, Fisher's exact test). Patients not undergoing transplantation had a median time of 8 months on therapy and a mean of 10 months. Toxicity was haematological (36% developing grade III-IV toxicity) and neurological (9%). There were only three episodes of clinical cystitis or gross haematuria. Infusional DICE is an easily administered and well tolerated programme with significant activity in refractory or relapsed NHL and may be useful as a tumour-reductive therapy prior to high-dose chemotherapy and autologous stem cell transplantation.

A consistent pattern of RIN1 rearrangements in oral squamous cell carcinoma cell lines supports a breakage-fusion-bridge cycle model for 11q13 amplification.

Gene amplification is a common feature of tumors. Overexpression of some amplified genes plays a role in tumor progression. Gene amplification can occur either extrachromosomally as double-minute chromosomes (dmin) or intrachromosomally in the form of homogeneously staining regions (hsrs). Approximately one-half of our oral squamous cell carcinomas (OSCCs) are characterized by amplification of band 11q13, usually as an hsr located entopically (occurring or situated at the normal chromosomal site, as opposed to ectopically). Using chromosomal fluorescence in situ hybridization (FISH), we confirmed the amplification of the cyclin D1 (CCND1/PRAD1) and fibroblast growth factor types 3 and 4 (FGF3/INT2 and FGF4/HSTF1) genes within the 11q13 amplicon in our series of primary OSCCs and derived cell lines. The human RIN1 gene was isolated as an RAS interaction/interference protein in a genetic selection in yeast and has been described as a putative effector of both the RAS and ABL oncogenes. We mapped RIN1 to 11q13.2. FISH analysis of 10 11q13-amplified OSCC cell lines revealed high-level RIN1 amplification in two cell lines. Three additional cell lines have what appear to be duplications and/or low-level amplification of RIN1, visible in both interphase and metaphase cells. The hybridization pattern of RIN1 on the metaphase chromosomes is particularly revealing; RIN1 signals flank the 11q13 hsr, possibly as a result of an inverted duplication. The gene amplification model of Coquelle et al. (1997) predicted that gene amplification occurs by breakage-fusion-bridge (BFB) cycles involving fragile sites. Our data suggest that the pattern of gene amplification at 11q13 in OSCC cell lines is consistent with a BFB model. RIN1 appears to be a valuable probe for investigating the process of gene amplification in general and, specifically, 11q13 amplification in oral cancer.

Chromosomal instability and cytoskeletal defects in oral cancer cells.

Oral squamous cell carcinomas are characterized by complex, often near-triploid karyotypes with structural and numerical variations superimposed on the initial clonal chromosomal alterations. We used immunohistochemistry combined with classical cytogenetic analysis and spectral karyotyping to investigate the chromosomal segregation defects in cultured oral squamous cell carcinoma cells. During division, these cells frequently exhibit lagging chromosomes at both metaphase and anaphase, suggesting defects in the mitotic apparatus or kinetochore. Dicentric anaphase chromatin bridges and structurally altered chromosomes with consistent long arms and variable short arms, as well as the presence of gene amplification, suggested the occurrence of breakage-fusion-bridge cycles. Some anaphase bridges were observed to persist into telophase, resulting in chromosomal exclusion from the reforming nucleus and micronucleus formation. Multipolar spindles were found to various degrees in the oral squamous cell carcinoma lines. In the multipolar spindles, the poles demonstrated different levels of chromosomal capture and alignment, indicating functional differences between the poles. Some spindle poles showed premature splitting of centrosomal material, a precursor to full separation of the microtubule organizing centers. These results indicate that some of the chromosomal instability observed within these cancer cells might be the result of cytoskeletal defects and breakage-fusion-bridge cycles.

Prereduction radiographs in clinically evident anterior shoulder dislocation.

The main study objective was to determine if experienced emergency physicians can accurately identify a subgroup of patients with anterior shoulder dislocation for whom prereduction radiographs do not alter patient management. Our prospective study evaluated 97 patients who presented to 2 ski-hill clinics and to our rural emergency department with possible shoulder dislocation between November 1996 and May 1997. Emergency physicians were certain of shoulder dislocation by clinical examination alone in 40 of 59 cases (67.8%) of possible dislocation. All 40 cases were found to have a dislocation (100%; 95% Cl, 91.19% to 100%), and the prereduction radiograph did not affect management of the injury. Prereduction radiographs added 29.6 +/- 12.68 minutes to treatment. We conclude that shoulder dislocation is often readily apparent from history and physical examination. When the experienced emergency physician is certain of the diagnosis of anterior shoulder dislocation, prereduction radiography delays treatment and does not alter management.

Readiness to perform cardiopulmonary resuscitation: an emerging strategy against sudden cardiac death.

OBJECTIVES: This investigation assessed motivational factors and psychosocial barriers that affect individual readiness to perform cardiopulmonary resuscitation (CPR). This is the first study to use the Transtheoretical model in assessing readiness to perform CPR. METHODS: A sample of 786 subjects, > or = 45 years of age and who resided in a private residence, were randomly selected to participate in a structured telephone interview. Data on motivational readiness, emotional state, perceived psychosocial barriers, and perceived efficacy in performing CPR were collected using dichotomous and Likert-type ratings. RESULTS: Subjects with greater motivational readiness expected to experience significantly fewer symptoms of emotional distress during a cardiac emergency and to encounter fewer psychosocial barriers. This group also reported greater efficacy in their ability to perform CPR. These findings were independent of gender, medical history, age, and educational level. CONCLUSIONS: Meaningful differences are apparent in individual readiness to perform CPR. These findings provide additional support for the need to tailor CPR training strategies using behavioral methods that enhance motivational readiness and decrease apprehension about anticipated emotional distress and psychosocial barriers.

Frequent allelic loss and homozygous deletion in chromosome band 8p23 in oral cancer.

Frequent loss of heterozygosity on chromosome 8p in a variety of human malignancies, including head and neck cancers, has suggested the presence of a tumor suppressor gene (or genes) associated with the pathogenesis of these cancers. To test the role of genetic alterations at 8p23 in oral carcinogenesis, we studied 51 squamous cell carcinomas of the head and neck and 29 oral squamous cell carcinoma cell lines for allelic loss using 7 microsatellite markers spanning approximately 5 cM of chromosome band 8p23. Twenty-three of 51 tumors (45%) and 23 of 29 cell lines (79%) showed allelic loss at 1 or more loci. Three cell lines showed homozygous deletion of loci within a 3 cM region defined by the markers D8S1781 and D8S262. Our results suggest that a tumor suppressor gene (or genes) is located in 8p23 and is associated with the development and/or progression of oral carcinomas.

Who should write admission orders?

The rural hospital environment differs from the urban hospital environment in that there are fewer physicians available to share the workload and to help out in an emergency. When a rural physician on call for emergency writes admission orders rather than disturb the patient's family physician, that rural physician accepts full responsibility for the patient until the patient's physician actually examines the patient and assumes care.

Preparation, attitudes and behaviour in nonhospital cardiac emergencies: evaluating a community's readiness to act.

OBJECTIVE: To determine how people in a moderately sized Ontario city believe they will react if they witness someone colapsing. DESIGN: Telephone survey. SETTING: The cities of Kitchener and Waterloo, part of the Regional Municipality of Waterloo, Ontario, with a combined population of 378,000. PARTICIPANTS: Households were randomly contacted and a questionnaire was administered, provided the respondent was over 44 years of age and agreed to be interviewed. Of 2479 households with eligible respondents, 811 (33%) completed the questionnaire. OUTCOMES: Age, sex, educational level, cardiac risk factors and cardiopulmonary resuscitation (CPR) training of respondents were determined, as well as actions they would take if cardiac arrest occurred in a family member at home or in stranger in the street, and associated emotions and barriers to implementing actions. RESULTS: Among the first three actions that respondents who were not prompted with possible responses said they would take, 311 (72%) witnessing a collapse at home, compared with 166 (44%) witnessing a collapse on the street, would call 911, the police or an ambulance. Other 'first three actions' in home collapse were checking for breathing (120 [28%]), checking for pulse (91 [21%]) and administering CPR (34 [8%]); these actions were less commonly selected in response to a strangers collapse and when respondents were not prompted. Respondents felt they would be more likely to perform CPR on a friend than on a stranger (OR 1.38, 95% CI 1.10 to 1.58). When asked how likely they would be to perform specific acts when witnessing a collapse, 254 (69%) of respondents thought they would call their family doctor and 179 (48%) thought they were likely to begin chest compressions. Barriers to performing CPR centred around legalities and disease transmission. CONCLUSION: Older people do not know how to act effectively in a cardiac emergency. Traditional CPR and public awareness programs have been ineffective in reaching this population; alternative means are required to help the public respond more effectively to cardiac emergencies.

Parental alleles of an imprinted mouse transgene replicate synchronously.

Molecular features of imprinted genes include differences in expression, methylation, and the timing of DNA replication between parental alleles. Whereas methylation differences always seem to be associated with differences in expression, differences in the timing of replication between parental homologs are not always seen at imprinted loci. These observations raise the possibility that differences in replication timing may not be an essential feature underlying genomic imprinting. In this study, we examined the timing of replication of the two alleles of the imprinted RSVIgmyc transgene in individual embryonic cells using fluorescence in situ hybridization (FISH). The cis-acting signals for RSVIgmyc imprinting are within RSVIgmyc itself. Thus, allele-specific differences in replication, if they indeed govern RSVIgmyc imprinting, should be found in RSVIgmyc sequences. We found that the parental alleles of RSVIgmyc, which exhibit differences in methylation, replicated at the same time. Synchronous replication was also seen in embryonic cells containing a modified version of RSVIgmyc that exhibited parental allele differences in both methylation and expression. These findings indicate that maintenance of expression and methylation differences between alleles does not require a difference in replication timing. The differences in replication timing of endogenous imprinted alleles detected by FISH might therefore reflect structural differences between the two alleles that could be a consequence of imprinting or, alternatively, could be unrelated to imprinting.

FHIT gene alterations in head and neck squamous cell carcinomas.

To determine whether the FHIT gene at 3p14.2 is altered in head and neck squamous cell carcinomas (HNSCC), we examined 26 HNSCC cell lines for deletions within the FHIT locus by Southern analysis, for allelic losses of specific exons FHIT by fluorescence in situ hybridization (FISH) and for integrity of FHIT transcripts. Three cell lines exhibited homozygous deletions within the FHIT gene, 55% (15/25) showed the presence of aberrant transcripts, and 65% (13/20) showed the presence of multiple cell populations with losses of different portions of FHIT alleles by FISH of FHIT genomic clones to interphase nuclei. When the data obtained by FISH and by reverse transcriptase-PCR analyses are combined, 22 of 26 cell lines showed alterations of at least one allele of the FHIT gene. Our data indicate that the FHIT gene is disrupted in HNSCCs and hence, loss of FHIT function may be important in the development and/or progression of head and neck cancers.

Characterization of six voltage-gated K+ currents in adult rat sensory neurons.

1. Previously three voltage-gated K+ currents were described in neurons from mammalian sensory ganglia: two transient and one sustained. Because there is considerable variability in the gating properties of these three currents, we have investigated the possibility that this variability reflects the presence of additional currents in sensory neurons. 2. Using whole cell patch-clamp techniques, we provide evidence for the existence of six voltage-gated K+ currents in cultured dorsal root ganglion (DRG) neurons from the adult rat. The six currents were identified on the basis of distinct biophysical and pharmacological properties; three currents are transient (IAf, IAht, and IAs), and three are sustained (IKi, IKlt, and IKn). 3. In addition to possessing distinct biophysical and pharmacological properties, four of the six currents are differentially expressed among subpopulations of DRG neurons. IAht is selectively expressed in small-diameter neurons. IKi is expressed more frequently in neurons with an action-potential shoulder, and both IAht and IAs are selectively coexpressed in neurons that respond to the algogenic agent capsaicin. IAf is selectively expressed in large-diameter neurons and is the only current expressed more frequently in neurons without an action-potential shoulder. 4. It is likely that much of apparent variability in the properties of the three voltage-gated K+ currents reported previously in vertebrate sensory neurons can be accounted for by the existence of at least three additional voltage-gated K+ currents described in this report.

Role of a Ca(2+)-dependent slow afterhyperpolarization in prostaglandin E2-induced sensitization of cultured rat sensory neurons.

To determine if inhibition of a Ca(2+)-dependent slow afterhyperpolarization (AHPslow) contributes to prostaglandin E2 (PGE2)-induced sensitization of DRG neurons, we have used patch-clamp electrophysiological techniques on cultured dorsal root ganglion (DRG) neurons from the adult rat. In support of a role for AHPslow in sensitization of DRG neurons, we demonstrate that: (1) AHPslow expression is restricted to a subpopulation of putative nociceptors; (2) burst duration is controlled by AHPslow in these neurons; and (3) in some neurons, PGE2 decreases AHPslow and produces a concomitant increase in the number of action potentials generated in response to depolarizing current injection. However, our results also demonstrate that AHPslow modulation is not sufficient to explain PGE2-induced sensitization in the majority of DRG neurons because: (1) the size of the population of DRG neurons expressing AHPslow is less than half the size of the population of DRG neurons sensitized by PGE2; (2) PGE2 produces a decrease in action potential threshold as well as an increase in the number of action potentials in response to current injection, while inhibition of AHPslow has little effect on threshold; and (3) the sensitizing effects of PGE2 are dissociated from its effects on AHPslow in more than half of neurons tested. We conclude that PGE2-induced sensitization must involve the modulation of ionic currents in addition to that underlying AHPslow.