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Biomedical subjects

C Russell

Publications and source records attributed to C Russell.

At least 37 records · Page 2Linked to original sources
PubMed1999

Contrast polarity and face recognition in the human fusiform gyrus.

Functional imaging has revealed face-responsive visual areas in the human fusiform gyrus, but their role in recognizing familiar individuals remains controversial. Face recognition is particularly impaired by reversing contrast polarity of the image, even though this preserves all edges and spatial frequencies. Here, combined influences of familiarity and priming on face processing were examined as contrast polarity was manipulated. Our fMRI results show that bilateral posterior areas in fusiform gyrus responded more strongly for faces with positive than with negative contrast polarity. An anterior, right-lateralized fusiform region is activated when a given face stimulus becomes recognizable as a well-known individual.

Adult↗
PubMed1999

Living can be hazardous to your health: how the news media cover cancer risks.

For more than two decades, the news media has bombarded the public with often conflicting information about health risks, contributing to an atmosphere of hype and hysteria about cancer and other diseases. Improvements in media reporting of health risks require greater efforts by both those who cover the news and those who create it. Guidelines for bringing more perspective and balance to media coverage of risk are provided. These include putting cancer in context with other diseases, explaining absolute and relative risks, differentiating between individual and population risks, stressing the degree of uncertainty of new research and how it fits with previous data, covering the process as well as end results of science, understanding different media constraints and needs, and taking into account the diverse backgrounds and needs of the target audience-the general public.

Guidelines as Topic↗
PubMed1999

Implications for improving risk communication through various channels: a discussion.

The news media need to improve their coverage of new and old cancer risks, avoiding sensational reporting of minor risks and underreporting of major ones. However, efforts to communicate about cancer risk to the general public need to go far beyond the traditional print and broadcast outlets into more innovative, personalized channels that can better educate individuals about the risks they face and what they can do about them.

Communication↗
PubMed1999

Standard Kausch-Whipple pancreatoduodenectomy.

Despite the increasing number of clinical trials in pancreatic cancer there are no widely accepted definitions of different types of resection for pancreatic cancer. An agreed definition of the standard Kausch-Whipple pancreatoduodenectomy was derived by a group of international experts at a meeting in Castelfranco Veneto, Italy, in May 1998. The lymph node groups to be removed en bloc with the pancreatoduodenectomy and described using the Japanese Pancreas Society classification were as follows: 13a and 13b; 17a and 17b; 12b1, 12b2 and 12c; and 14a and 14b. Limited segmental major venous resection and adjacent organ resection, if required, may be included as part of a standard pancreatoduodenectomy. The pylorus-preserving procedure also may be included as part of standard resection, but not for tumours of the anterior-superior part of the head of the pancreas. Wider adoption of the definition of standard Kausch-Whipple resection will enable a more objective comparative analysis of the radicality of resection between institutions and permit a more coherant analysis on the type of surgery undertaken in multicentre adjuvant studies.

Combined Modality Therapy↗
PubMed1999

User satisfaction with realtime teleneurology.

User satisfaction (i.e. that of patients, medical staff at a remote hospital and medical staff at a neurological centre) with realtime teleneurology consultations was studied prospectively. Twenty-five patients with neurological problems admitted to a hospital without permanent neurological cover were assessed from a neurological centre by specialist neurologists using realtime video-links transmitting at 384 kbit/s. All users reported high levels of satisfaction with the technical aspects of the consultations. Patients, almost universally, reported confidence in teleneurology as a means of dealing with their presenting complaints. Similarly, medical staff at either site felt confident in managing patients using teleneurology and almost always felt that a telephone consultation would not have achieved as good an outcome. No major organizational problems were identified. These findings suggest overall user satisfaction with realtime teleneurology for managing patients with neurological problems admitted to hospitals that do not have resident neurologists.

Adolescent↗
PubMed1999

MDR1 gene expression in primary and advanced breast cancer.

P-glycoprotein (Pgp)-associated multidrug resistance (MDR) is related to intrinsic and acquired cross resistance to anthracyclines, vinca alkaloids, and other antineoplastic antibiotics. Expression of MDR1 is widely considered to play an important role in conferring resistance to adjuvant chemotherapy in women with breast tumor cells in women with disseminated disease, although data supporting this view is, at best, conflicting. The expression of MDR1 gene and its gene product, P-glycoprotein, was investigated in primary and advanced breast cancers (both previously untreated and previously treated on specific treatment protocols) to assess the role of P-glycoprotein in determining responsiveness to adjuvant chemotherapy. Expression was assessed by immunohistochemistry, reverse transcription-PCR (RT-PCR), Northern Blot and Western Blot. MDR1 mRNA was detected in 40% of the breast cancers tested by RT-PCR with 40 cycles of PCR amplification. When reducing the PCR amplification cycles to 28, the MDR1 gene expression signal disappeared from breast cancers of the highest expressers; however, known MDR1 positive control normal tissues, such as adrenal, kidney, and liver continued to show an expression product. Western and Northern blots failed to demonstrate the MDR1 gene product, P-glycoprotein, in these breast cancers. In contrast, physiologic levels of P-glycoprotein was clearly detected in normal adrenal, kidney, and liver by these techniques. Immunohistochemistry confirmed that breast carcinoma cells lacked P-glycoprotein expression; however, interstitial mononuclear cells, morphologically consistent with lymphocytes or macrophages did show immunostaining in some of these breast tumors. MDR1 gene expression identified by RT-PCR was not correlated either with response to paclitaxel therapy (29 patients able to be evaluated, p = 0.34, Fisher Exact Test) or overall survival (32 breast cancer patients with clinical follow-up information, p = 0.336, log rank). In conclusion, P-glycoprotein was not expressed in breast carcinoma cells at significant levels, although it was expressed in stomal lymphocytes or macrophages. These results suggest that P-glycoprotein does not play a significant role in multidrug resistance of breast cancer.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Exploring the experience of type 2 diabetes in urban aboriginal people.

The experience of diabetes among urban Aboriginal people (status and non-status Indians) was explored through a qualitative study. Because researchers have focused almost exclusively on Aboriginal people living on reserves or in isolated rural communities in Canada, this study conducted face-to-face interviews with participants (n = 20) living in the city of Winnipeg, Manitoba. The data generated 3 themes: diabetes as an omnipresent and uncontrollable disease; beyond high sugar: diabetes revealed in bodily damage; and the good, the bad, and the unhelpful: interactions with health-care providers. Findings from this study and previous research support the existence of a pan-Aboriginal model of diabetes. This contemporary cultural stance appears to transcend geography and has implications for the prevention and treatment approaches used in programs and health services for Aboriginal people living with diabetes.

Adaptation, Psychological↗
PubMed1999

Mapping HLA for single nucleotide polymorphisms.

Knowledge of DNA sequence variation may help us understand how genetic variability gives rise to functional variability and, in so doing, revolutionize the development of strategies to combat and prevent disease. Single nucleotide polymorphisms (SNPs) are stable, inherited, biallelic, single base pair differences which are present in the human genome at a density of 1 to 10 per 1,000 nucleotides. It is anticipated that SNPs will account for much of the functional heterogeneity in gene expression and protein activity exhibited in the human population. Susceptibility to or protection from a number of diseases, particularly those of autoimmune etiology, has been associated with specific alleles of the human leukocyte antigen (HLA) complex. Interestingly, the precise molecular defects in the HLA genes are unknown and the notion that non-HLA genes, within the same chromosomal region, are involved remains a formal possibility. We have determined the nucleotide sequence of a contiguous 2.2 Mbp segment of chromosome six that includes all of the HLA class I region, and have identified over 10,000 SNPs therein. Because of the derivative knowledge of gene and SNP content and position, the scientific community is now uniquely poised to identify disease-contributory SNPs that lie within the MHC.

HLA Antigens↗
PubMed1998

Comprehensive needs assessment of clinical breast evaluation skills of primary care residents.

BACKGROUND: Health care reform places primary care (PC) physicians in an increasingly significant role for breast cancer screening and diagnosis. This study assessed the adequacy of traditional PC resident training to prepare physicians for this front-line role. METHODS: Sixty-eight primary care residents, representing seven training programs, participated in a multidimensional needs assessment study of clinical breast evaluation skills. RESULTS: Performance deficiencies noted in each component were most significant in (1) common breast problem management (problem-solving mean 44.51 +/- 11.01); (2) breast examination skills (mean 49.65 +/- 14.48%); and (3) lump detection sensitivity (mean 40.20 +/- 17.10%). Overall examination reliability was good (alpha = .82). Factorial ANOVA revealed significant performance differences among training programs. Residency programs with higher performance levels reported dedicated breast curricula, and residents rated these programs as providing more adequate training. Programs with poorer performance in breast examination lacked curriculum emphasis, with residents describing training received as poor to fair. CONCLUSION: This study demonstrated performance deficits in the clinical breast evaluation skills of graduating PC residents that have not been captured by traditional evaluation methodologies. This may represent a limitation in the ability of many PC physicians to effectively screen and diagnose patients with breast cancer.

Adult↗
PubMed1998

Discriminative stimulus properties of low doses of ethanol in humans.

Discriminative stimulus properties of low doses of ethanol were evaluated in humans using established behavioural drug discrimination procedures. Twenty-five moderate drinkers (12 females and 13 males) were trained to discriminate placebo from 0.2 g/kg ethanol in 200 ml tonic water mixed with Tabasco sauce and drunk in portions of 50 ml every 15 s. Seventeen of the subjects (ten females and seven males) were able to reach criterion performance (at least 80% correct responses). Generalisation responding across ethanol doses of 0 (placebo), 0.025, 0.05, 0.1 and 0.2 g/kg was examined the day after training using a procedure in which subjects reported the extent to which the test stimulus resembled the training dose. At the end of each generalisation session, self ratings of mood changes, physiological responses and performance in a working memory and a time estimation task were evaluated. Subjects were able to distinguish the three higher doses of ethanol from placebo. Self ratings indicated that subjects' ability to distinguish ethanol from placebo was related, at the highest dose, to change of taste, but to feelings of light-headedness at the lower doses. Ethanol administration influenced skin conductance measurements but there was no relationship found between changes in skin conductance and the ethanol discriminative stimulus. These data suggest a difference in the nature of the discriminative stimulus of ethanol between high (training) and low (generalising) doses as indicated in the subjective reports.

Adolescent↗
PubMed1998

Effects of acid-etching on the tensile properties of demineralized dentin matrix.

OBJECTIVES: Little research has been done to evaluate the effects of acids commonly used in adhesive dentistry, on the tensile properties of the demineralized dentin matrix. The purpose of this study was to evaluate the effects of a number of acidic conditioners on the ultimate tensile strength (UTS) and modulus of elasticity (E) of human coronal dentin matrix. METHODS: Small hour-glass shaped (for UTS) or l-beam shaped (for determination of E) were prepared from mid-coronal dentin of extracted human third molars. After protecting the ends with varnish, the middle of the specimens was completely demineralized in 0.5 M EDTA (pH 7). UTS was determined by tensile stressing to failure. Modulus of elasticity was calculated from stress strain curves. The results were analyzed by ANOVA and Student-Neuman-Keuls test at the 95% confidence level. RESULTS: Brief (ca. 1-2 min) exposure of demineralized dentin matrix to acids had no measurable effects on its tensile properties. Ten-minute exposures to 2.5% and 17.5% nitric acid lowered (p < 0.05) the UTS compared to phosphate buffered saline (PBS)-exposed controls. Exposure of the decalcified dentin to 10% citric acid containing 3% ferric chloride, 10% citric acid, 37% phosphoric acid or 17.5% nitric acid containing 3% ferric chloride for 10 min had no effect on UTS. None of these acids consistently lowered stiffness. SIGNIFICANCE: The results indicate that relatively long exposures to acids are required to alter the tensile properties of demineralized dentin. It is unlikely that the brief exposures to acids that are used in adhesive dentistry would acutely weaken the physical properties of demineralized dentin. However, long-term studies should be done to determine if such treatment increases the susceptibility of the matrix to hydrolysis.

Acid Etching, Dental↗
PubMed1998

The new varicella vaccine: efficacy, safety, and administration.

Since the FDA has given approval for the manufacture of a varicella vaccine (Varivax), nurses are beginning to administer the vaccine to children. Over 11,000 healthy and immunocompromised children have been immunized since 1979. Varivax has been found to be 95% to 100% effective in conferring immunity for at least 10 years, and it appears to be a safe vaccine. This article presents a review of the research literature on clinical trials of Varivax, and the risks, benefits, and projected cost of the vaccine. Precautions, contraindications, and guidelines for administration are tabled and discussed in a sample case using the Health Belief Model as a theoretical framework. The article includes a discussion of areas for further research and implications for nursing.

Chickenpox↗
PubMed1998

Dosage-sensitive and complementary functions of roundabout and commissureless control axon crossing of the CNS midline.

commissureless and roundabout lead to complementary mutant phenotypes in which either too few or too many axons cross the midline. The robo;comm double-mutant phenotype is identical to robo alone, suggesting that in the absence of robo, comm is no longer required. Comm is expressed on midline cells; Robo is expressed in a dynamic fashion on growth cones and appears to function as an axon guidance receptor. robo function is dosage-sensitive. Overexpression of comm is also dosage-sensitive and leads to a phenotype identical to robo loss-of-function. Comm controls Robo expression; increasing Comm leads to a reduction of Robo protein. The levels of Comm and Robo appear to be tightly regulated to assure that only certain growth cones cross the midline and that those growth cones that do cross never do so again.

Animals↗
PubMed1998

Murine MPS I: insights into the pathogenesis of Hurler syndrome.

Mucopolysaccharidosis type I (MPS I) is an autosomal recessive disease resulting from deficiency of the lysosomal enzyme alpha-L-iduronidase. A murine model which shows complete deficiency in alpha-L-iduronidase activity has been developed and shows phenotypic features similar to severe MPS I in humans. Here we report on the long-term clinical, biochemical, and pathological course of MPS I in mice with emphasis on the skeletal and central nervous system (CNS) manifestations. Affected mice show a progressive clinical course with the development of coarse features, altered growth characteristics and a shortened life span. Progressive lysosomal accumulation is seen in all tissues. Skeletal manifestations represent the earliest clinical finding in MPS I mice with histologic analysis of growth plate and cortical bone revealing evidence that significant early pathology is present. Analysis of the CNS has revealed the novel finding of progressive neuronal loss within the cerebellum. In addition, brain tissue from MPS I mice shows increased levels of GM2 and GM3 gangliosides. This murine model clearly shows phenotypic and pathologic features which mimic those seen in severe human MPS I and should be an invaluable tool for the study of the pathogenesis of generalized storage disorders.

Animals↗
PubMed1998

Older people's lives in the inner city: hazardous or rewarding?

An exploratory, qualitative study was used to investigate the social health needs of older residents of a low-income inner-Sydney area characterised by multiple social and environmental hazards. The research was conducted to inform the development by the South Eastern Sydney Area Health Promotion Unit of a strategy to promote the health, wellbeing and independence of older people. As part of a needs assessment process, the investigation focused on specific subgroups of the population believed to be highly disadvantaged and neglected. In-depth interviews were conducted with 40 residents aged 60 to 86 years who were recruited through community centres, service providers and neighbours. The interviews were supplemented by observational field notes. We describe key dimensions of the physical and social environment, the many hazards it presented to vulnerable elderly residents and the practices they adopted in meeting their everyday needs in relation to shopping, meals, mobility outside the home and social participation. The description is from the perspectives of residents themselves. Key factors discussed include the neighbourhood, housing, activities of daily living, safety and security, and social participation. We explore the implications of our findings for the development of effective public health practice. The environmental hazards, such as pedestrian safety and traffic management, affect the whole population and require interventions at government level. Others, such as inadequate hygiene and food storage facilities in rented premises, also require an approach at the level of public policy and environmental change, but need to be carefully targetted and implemented.

Aged↗
PubMed1997

Treatment of recurrent malignant glioma with BCNU-fluosol and oxygen inhalation. A phase I-II study.

OBJECTIVES: To evaluate the toxicity and response rate following BCNU with oxygen inhalation and escalating dosages of fluosol administered to patients with radiographic progression of malignant glioma after definitive surgery and radiotherapy. METHOD: This single arm, phase I-II multicenter trial, enrolled 99 patients with malignant gliomas recurrent after definitive surgery and radiotherapy. All patients received a fixed dose (200 mg/m2) of BCNU along with 100% oxygen and fluosol, a perfluorochemical. Fluosol doses were escalated between patients (150, 275, 400 and 600 ml/m2). Treatment was repeated every 6 weeks for a maximum of 6 cycles. Patients were assessed for toxicity at the time of infusion and sequentially thereafter. Response was evaluated clinically and radiologically at least every 6 weeks. RESULTS: Treatment was well tolerated. Dose reductions were required at least once in 18 patients, treatment delays were necessary at least once in 33 patients. Grade 3-4 leukopenia occurred in 6 patients (12 events), grade 3-4 thrombocytopenia in 10 patients (25 events) and grade 3-4 liver enzymes elevations in 18 patients (31 events). Higher fluosol dosages did not produce increases in toxicity or responses. Response or stabilization was seen in 57% (38% were stabilizations) of the patients who entered the trial with progressive disease. The median time to progression was 45 weeks, and median survival was 66 weeks for patients who had response or stabilization. For patients with glioblastoma response/stabilization was seen in 45% with a mean duration of 24 weeks, for patients with anaplastic astrocytoma response/stabilization was seen in 68% with a mean duration of 50 weeks. CONCLUSION: This treatment regimen is well tolerated. Our results suggest fluosol may enhance the effectiveness of BCNU for the treatment of recurrent malignant gliomas. Future studies will be performed using fluosol at the dose of 400 ml/m2.

Adolescent↗