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Biomedical subjects

Pamela Jones

Publications and source records attributed to Pamela Jones.

7 recordsLinked to original sources
PubMed2006

Exogenous sphingomyelinase increases collagen and sulphated glycosaminoglycan production by primary articular chondrocytes: an in vitro study.

We previously established a role for the second messenger ceramide in protein kinase R (PKR)-mediated articular cartilage degradation. Ceramide is known to play a dual role in collagen gene regulation, with the effect of ceramide on collagen promoter activity being dependent on its concentration. Treatment of cells with low doses of sphingomyelinase produces small increases in endogenous ceramide. We investigated whether ceramide influences articular chondrocyte matrix homeostasis and, if so, the role of PKR in this process. Bovine articular chondrocytes were stimulated for 7 days with sphingomyelinase to increase endogenous levels of ceramide. To inhibit PKR, 2-aminopurine was added to duplicate cultures. De novo sulphated glycosaminoglycan and collagen synthesis were measured by adding [35S]-sulphate and [3H]-proline to the media, respectively. Chondrocyte phenotype was investigated using RT-PCR and Western blot analysis. Over 7 days, sphingomyelinase increased the release of newly synthesized sulphated glycosaminoglycan and collagen into the media, whereas inhibition of PKR in sphingomyelinase-treated cells reduced the level of newly synthesized sulphated glycosaminoglycan and collagen. Sphingomyelinase treated chondrocytes expressed col2a1 mRNA, which is indicative of a normal chondrocyte phenotype; however, a significant reduction in type II collagen protein was detected. Therefore, small increments in endogenous ceramide in chondrocytes appear to push the homeostatic balance toward extracellular matrix synthesis but at the expense of the chondrocytic phenotype, which was, in part, mediated by PKR.

Animals↗
PubMed2006

What do dental students think about mandatory laptop programs?

In spite of efforts by many dental schools to provide information technology resources for students, only a handful of studies have been conducted to determine what dental students think about these initiatives. There are no reports in the literature describing students' perceptions of mandatory laptop programs, which are now being implemented by at least 25 percent of North American dental schools. In schools that have implemented laptop programs, students are required either to enroll with their own laptops that meet specifications or to purchase a laptop from the school at matriculation. In some schools, students are also required to purchase curriculum support software that is bundled with the laptop. This study was conducted to determine students' opinions at U.S. dental schools with mandatory laptop programs about these aspects of this information technology initiative: frequency of use, perceived necessity of use, note-typing during lectures, effectiveness of training, influence on study habits, benefits, implementation problems, added value in relation to added tuition costs, impact on quality of dental education, overall rating of the laptop experience, and impact of the laptop on use of other electronic curriculum resources. Responses of students at schools that purchased packaged curriculum support software from a commercial vendor were compared with students' responses at schools where faculty provided their own educational software. Responses were also compared among freshmen, sophomores, and upperclassmen in a cross-sectional sample. In 2004, approximately 800 dental students at fourteen dental schools responded to eleven questions that requested their impressions and evaluation of mandatory laptop programs and associated educational software. These questions comprised one section of the IREC Students' Questionnaire (IREC=Institutional Readiness for Electronic Curriculum) that assessed students' perceptions of various aspects of information technology at their schools. The majority of students (63 percent) reported that the laptop and associated software were not essential for successful performance in their courses primarily because few instructors had modified their courses to take advantage of laptop capacities. Slightly more than half of the students reported their training was good or excellent, but felt that classroom-based "one size fits all" training was not effective. Less than 15 percent of the students reported that they had made substantial changes in their study habits as a consequence of the laptop program. The benefits perceived by students were primarily related to enhanced email communication with classmates and instructors and convenient access to the Internet and teachers' PowerPoint presentations. Implementation barriers included the inconvenience of carrying laptops to classes, lack of incentive to use the laptop and software because instructors did not require it, and poor quality software. Only 32 percent of students agreed that the value of the laptop and associated software was equal to the added tuition costs. Less than half of the students perceived that the laptop and software had improved the quality of their education, but more than 70 percent rated their overall experiences with laptops as "okay," "good," or "excellent." Freshmen expressed significantly more positive attitudes about the frequency of use, cost-effectiveness, educational value, and overall quality of laptops and bundled software than did upperclassmen. A significantly higher percentage of students at schools affiliated with a software vendor reported that laptops were essential in courses than students at schools with locally produced software, but students at vendor-supplied schools rated the cost-effectiveness significantly lower. Overall, students' assessment of mandatory laptop programs was mixed although freshmen provided significantly more positive responses than did upperclassmen. Incorporation of the e-curriculum into dental schools appears to be following a similar pattern as problem-based learning (PBL) in the 1980s and 1990s. Recommendations for enhancing future e-curricula are proposed based on lessons learned from both information technology and PBL implementation.

Adult↗
PubMed2006

Pathophysiological responses of MRC-5 cells exposed to various doses of x-ray radiation.

The numbers of x-ray procedures used as diagnostic tools are on the rise; these procedures are being used more frequently than ever before. The radiation effect from these procedures are said to be minimal, however there is a significant increase in cellular damage that may lead to cellular aberrations. The objective of this study was to expose human lung fibroblast (MRC-5) cells to various doses of x-ray radiation and evaluate its effects on the proliferation and morphology of the cells. Based on the review of the literature, we selected doses similar to other researchers, the doses were 2, 6 and 10 (Gy), evaluated after 24, 48 and 72 hours of incubation. The results indicated a 25% decrease in the cell number after 48 and 72 hours (p < 0.05), in all groups exposed to either dose of radiation. After 24 hours, there was not a statistically significant difference between the groups exposed to either dose of radiation. Morphologically, the cells exhibited significant changes when exposed to either, 2, 6 or 10 Gy of radiation. The cells showed multiple nucleoli with all doses, and mitotic figures were observed with a dose of 2 Gy. After a dose of 6 Gy, hydropic swelling due to excess fluid in the cytoplasm was noted as well as multiple nucleoli. After 48 and 72 hours, severe vacuolization with various degrees of hypertrophy and atrophy was noted with a dose of 10 Gy. Further analysis revealed that the higher the radiation dose, the more severe the damage after 48 and 72 hours, however, significant damage was evident with all doses, even as low as 2 Gy.

Cell Line↗
PubMed2006

The physiological effect of conventional treatment with epigallocatechin-3-gallate, thymoquinone, and tannic acid on the LNCaP cell line.

Antioxidants are substances that function to protect cells from damage caused by unstable free radicals, which are responsible for damage that may lead to cancer. (Blot et al., 1993). Several antioxidants have been discussed for use in prevention and treatment of prostate carcinoma. Epidemiological evidence has indicated that these antioxidants may reduce the risk of prostate cancer by underlying mechanisms that remain unclear. The LNCaP cell line was introduced by inoculation from a supraclavicular lymph node metastasis of human prostate cancer (Horoszewicz et al., 1983). The aim of this study was to use the androgen-dependent LNCaP human prostate cancer cell line as a cell model to evaluate the physiological effects to conventional treatments with both low (LD) and high doses (HD) of epigallocatechin-3-gallate (EGCG), thymoquinone (TQ), and tannic acid (TA). Following treatment, cells were incubated and the various groups were evaluated at 24, 48, and 72 hours. After 24, 48, and 72 hours of incubation, all treated cells caused a reduction in cell growth, but the TQHD treated group seemed to be the most potent. The TQHD group also demonstrated the greatest decrease in total protein levels in comparison to the control. According to one-way analysis of variance (ANOVA), significant differences were observed (P < 0.001). Upon observation of the prostatic specific antigen (PSA) values, all groups showed decreased levels; however, the TQHD treated group showed an initial suppression after 24 hours and then finally adapted to treatment after 48 and 72 hours. Malondialdehyde (MDA) values were also assessed at the same three time periods (24, 48, and 72 hours) as an indicator of membrane integrity. After 24 hours of incubation, the TAHD group demonstrated the greatest increase in MDA levels. Morphologically, the cells demonstrated significant changes, such as swelling and irregularity in appearance upon antioxidant exposure. These findings reveal that antioxidants may serve as agents for prostate cancer prevention by providing safer and effective treatments for prostate cancer; however, further experiments are needed to understand the interactions involved.

Antineoplastic Agents↗
PubMed2004

Preliminary visual field preservation after staged CyberKnife radiosurgery for perioptic lesions.

OBJECTIVE: The limited radiation tolerance of the optic nerves and the optic chiasm makes it a challenge to treat immediately adjacent lesions with radiosurgery. Staged or hypofractionated radiosurgery has the virtue of combining the accuracy and conformality of radiosurgery with the normal tissue-sparing benefits of fractionation. We describe a consecutive series of patients with meningiomas and pituitary adenomas abutting the anterior visual pathways who were treated with staged, image-guided radiosurgery. METHODS: Thirty-four patients with either meningiomas (20 patients) or pituitary adenomas (14 patients) within 2 mm of the optic apparatus were treated. Several patients had previously been treated with conventional fractionated radiotherapy (5 patients) or subtotal surgical resection (23 patients). Radiosurgery was delivered in two to five stages to a cumulative average marginal dose of 20.0 Gy. Visual testing and clinical examinations were performed before treatment and at follow-up intervals beginning at 6 months after treatment. RESULTS: The mean follow-up period was 29 months (range, 15-62 mo). Pre- and posttreatment vision was unchanged in 20 patients, improved in 10, and worse in 3. One patient died during follow-up as a result of an unrelated cardiac event. Visual loss was accompanied by tumor progression in two cases. In a third patient with a multiply recurrent adrenocorticotropic hormone-secreting pituitary adenoma, injury to one optic nerve occurred after both a prior course of radiotherapy and three separate sessions of radiosurgery. CONCLUSION: Staged radiosurgery resulted in high rates of tumor control and preservation of visual function. Ninety-one percent of patients retained their presurgical vision. Staged radiosurgery may be a safe and effective alternative to either surgery or fractionated radiotherapy for selected lesions adjacent to the optic apparatus.

Adenoma↗
PubMed2004

Electronic curriculum implementation at North American dental schools.

Electronic curriculum, or E-curriculum, refers to computer-based learning including educational materials available on CD or DVD, online courses, electronic mechanisms to search the literature, email, and various applications of instructional technology including providing laptops to students, multimedia projection systems, and Internet-compatible classrooms. In spite of enthusiasm about the potential for E-curriculum to enhance dental education, there is minimal guidance in the literature to assist schools with implementation. The study objectives were: 1) identify U.S. and Canadian dental schools that have initiated mandatory laptop programs and assess cost, faculty development issues, extent of curricular use, problems, and qualitative perceptions; 2) determine the extent to which twenty-two other E-curriculum resources were available and used at North American dental schools; and 3) identify factors that influenced E-curriculum implementation. A twenty-six item questionnaire, known as the Electronic Curriculum Implementation Survey (ECIS), was mailed to all sixty-six North American dental schools (ten Canadian and fifty-six U.S. schools) during 2002-03 with a response rate of 100 percent. Twenty-five of the twenty-six ECIS questions employed a menu-driven, forced choice format, but respondents could provide amplifying comments. Fifty-three questionnaires were completed by associate deans for academic affairs, three by deans, and ten by instructional technology (IT) managers, IT committee chairs, or directors of dental informatics departments. The survey found that E-curriculum implementation among North American dental schools is following the classic innovation pattern in which a few early adopting institutions proceed rapidly while the majority of potential adopters make modifications slowly. Fourteen U.S. dental schools have established mandatory laptop programs for students. Ten of these laptop programs were created in the past two years; respondents reported numerous growing pains but were generally pleased with their progress. Other E-curriculum capabilities were incorporated into courses more frequently at laptop schools than the fifty-two non-laptop schools including websites, online course evaluations, and instructor use of email to communicate with students. Few dental schools use online courses, and at most schools, few faculty have received training in online instructional techniques. Virtually all North American dental schools have provided substantial instructional technology resources to their faculty, but use of twenty-two components and capabilities of E-curriculum was limited, especially at schools without laptop programs. Various faculty-related issues were reported as implementation barriers including lack of time, skill, and incentive to develop educational software. We conclude that many North American dental schools, especially those with laptop programs, are functioning at the "learn by doing" phase of initial implementation in a four-stage innovation adoption model. E-curriculum planners should pay close attention to implementation problems that occur at this stage where many innovation efforts break down.

Canada↗