Biomedical subjects

E Rogers

Publications and source records attributed to E Rogers.

At least 19 recordsLinked to original sources

PubMed2006

Torso flexion modulates stiffness and reflex response.

Neuromuscular factors that contribute to spinal stability include trunk stiffness from passive and active tissues as well as active feedback from reflex response in the paraspinal muscles. Trunk flexion postures are a recognized risk factor for occupational low-back pain and may influence these stabilizing control factors. Sixteen healthy adult subjects participated in an experiment to record trunk stiffness and paraspinal muscle reflex gain during voluntary isometric trunk extension exertions. The protocol was designed to achieve trunk flexion without concomitant influences of external gravitational moment, i.e., decouple the effects of trunk flexion posture from trunk moment. Systems identification analyses identified reflex gain by quantifying the relation between applied force disturbances and time-dependent EMG response in the lumbar paraspinal muscles. Trunk stiffness was characterized from a second order model describing the dynamic relation between the force disturbances versus the kinematic response of the torso. Trunk stiffness increased significantly with flexion angle and exertion level. This was attributed to passive tissue contributions to stiffness. Reflex gain declined significantly with trunk flexion angle but increased with exertion level. These trends were attributed to correlated changes in baseline EMG recruitment in the lumbar paraspinal muscles. Female subjects demonstrated greater reflex gain than males and the decline in reflex gain with flexion angle was greater in females than in males. Results reveal that torso flexion influences neuromuscular factors that control spinal stability and suggest that posture may contribute to the risk of instability injury.

Abdomen↗

PubMed2004

Interleukin-2, interferon-alpha and 5-fluorouracil immunotherapy for metastatic renal cell carcinoma: the all Ireland experience.

OBJECTIVE: To analyse the long-term efficacy of combined interferon-alpha (IFN-alpha) and interleukin-2 (IL-2) subcutaneously, with 5-fluorouracil (5-FU) intravenously in a general multicentre setting, as treatment for metastatic renal cell carcinoma (RCC). METHODS: Fifty-nine patients with metastatic RCC were scheduled to receive an 8-week cycle of immunotherapy. Karnofsky score ranged from 70 to 100 (median 90). Thirty-one patients at presentation had metastases of which 14 underwent nephrectomy. Metastases occurred in multiple organs (lung 74%, mediastinal lymphadenopathy 22%, bone 21%). Therapeutic response and survival were analysed. RESULTS: Nine patients died from disease progression prior to completion of one full cycle. Six cases (10%) have stable disease at a follow-up of 51 months (range 20-88 months). Currently 11 patients (19%) are alive at a mean follow-up of 45 months (range 18-88 months). Forty-eight patients (81%) died of their disease at a mean follow-up of 10 months (range 0.5-46 months). Survival rate at 1 year was 53%, at 2 years 21%, at 3 years 16% and at 5 years 5%. Overall median survival is 10 months. CONCLUSION: IL-2 and IFN-alpha with 5-FU based immunotherapy achieve durable survival rates at 3 years in a minority of patients. Addition of 5-FU does not increase survival in our group. This study population is very different to other reported series. However it reflects better the entire population with metastatic RCC though results are subsequently poorer. Identifying patients that will respond is paramount.

Adult↗

PubMed2004

Dietary supplementation with apple juice concentrate alleviates the compensatory increase in glutathione synthase transcription and activity that accompanies dietary- and genetically-induced oxidative stress.

Increased oxidative stress, which can arise from dietary, environmental and/or genetic sources, contributes to the decline in cognitive performance during normal aging and in neurodegenerative conditions such as Alzheimer's disease. Supplementation with fruits and vegetables that are high in antioxidant potential can compensate for dietary and/or genetic deficiencies that promote increased oxidative stress. We have recently demonstrated that apple juice concentrate (AJC) prevents the increase in oxidative damage to brain tissue and decline in cognitive performance observed when transgenic mice lacking apolipoprotein E (ApoE-/-) are maintained on a vitamin-deficient diet and challenged with excess iron (included in the diet as a pro-oxidant). However, the mechanism by which AJC provided neuroprotection was not conclusively determined. Herein, we demonstrate that supplementation with AJC also prevents the compensatory increases in glutathione synthase transcription and activity that otherwise accompany maintenance of ApoE-/- mice on this vitamin-free diet in the presence of iron. Inclusion of the equivalent composition and concentration of sugars of AJC did not prevent these increases. These findings provide further evidence that the antioxidant potential of AJC can compensate for dietary and genetic deficiencies that otherwise promote neurodegeneration.

Aging↗

PubMed2001

Application of the concept of an electrophoretic ratchet.

Fractionation via a gel electrophoretic ratchet has previously succeeded for comparatively large (radius R > or = 95 nm) spheres (Serwer, P, Griess, G.A., Anal. Chim. Acta 1998, 372, 299-306). The electrical oscillations are the following electrical field pulses: high field --> low field --> high field, etc. The field is inverted after each pulse; the time-integral of the field can be zero. Response to the ratchet is caused by steric trapping in the high field-direction, but not in the low field-direction. Trapping and, therefore, response to the ratchet decrease as R decreases. The smaller spheres do not respond to the ratchet. In the present study, spheres with R values smaller than 95 nm are made, for the first time, to respond to a similar gel electrophoretic ratchet. To achieve this objective, the heterogeneity of pore size is increased for the gel used. The heterogeneity of pore size is increased by (i) forming the gel with degraded hydroxyethyl agarose, and (ii) gelling at comparatively high temperature. If a particle still does not respond to the ratchet (because the particle is too small), this particle has a net migration in the high field-direction, when the above-described pulsed field is biased in the high field-direction. If a particle does respond to the improved ratchet, the particle has a net migration in the low field-direction. Here, the R of ratchet-responding spheres is reduced to 30-50 nm. These ratchet-responding spheres include both intact bacteriophage particles (R = 30 nm) and latex spheres. The smaller ratchet-responding spheres have an electrophoretic mobility that decreases in magnitude as the electrical field increases in magnitude. A ratchet-based procedure is developed here to achieve continuous preparative gel electrophoresis.

Bacteriophage T3↗

PubMed2001

Two zinc finger proteins, OMA-1 and OMA-2, are redundantly required for oocyte maturation in C. elegans.

Oocytes are released from meiotic prophase I arrest through a process termed oocyte maturation. We present here a genetic characterization of oocyte maturation, using C. elegans as a model system. We show that two TIS11 zinc finger-containing proteins, OMA-1 and OMA-2, express specifically in maturing oocytes and function redundantly in oocyte maturation. Oocytes in oma-1;oma-2 mutants initiate but do not complete maturation and arrest at a defined point in prophase I. Two maturation signal-induced molecular events, including the maintenance of activated MAP kinase, do not occur in Oma oocytes. The Oma prophase arrest is released by inactivation of a MYT-1-like kinase, suggesting that OMA-1 and OMA-2 function upstream of MYT-1 as positive regulators of prophase progression during meiotic maturation.

Alleles↗

PubMed2001

Homocysteine potentiates beta-amyloid neurotoxicity: role of oxidative stress.

The cause of neuronal degeneration in Alzheimer's disease (AD) has not been completely clarified, but has been variously attributed to increases in cytosolic calcium and increased generation of reactive oxygen species (ROS). The beta-amyloid fragment (Abeta) of the amyloid precursor protein induces calcium influx, ROS and apoptosis. Homocysteine (HC), a neurotoxic amino acid that accumulates in neurological disorders including AD, also induces calcium influx and oxidative stress, which has been shown to enhance neuronal excitotoxicity, leading to apoptosis. We examined the possibility that HC may augment Abeta neurotoxicity. HC potentiated the Abeta-induced increase in cytosolic calcium and apoptosis in differentiated SH-SY-5Y human neuroblastoma cells. The antioxidant vitamin E and the glutathione precursor N-acetyl-L-cysteine blocked apoptosis following cotreatment with HC and Abeta, indicating that apoptosis is associated with oxidative stress. These findings underscore that moderate accumulation of excitotoxins at concentrations that alone do not appear to initiate adverse events may enhance the effects of other factors known to cause neurodegeneration such as Abeta.

Acetylcysteine↗

PubMed2000

Unlimited increase in the resolution of DNA ladders.

Fractionation of DNA ladders by gel electrophoresis is limited by the progressive compressing of the long DNA end of a ladder. Improvement in the resolution of this DNA is achieved by use of the following two-step electrophoresis. Initially, the DNA ladder is fractionated by conventional constant field agarose gel electrophoresis. Subsequently, gel electrophoresis is performed in the reverse direction by pulsing the electrical field (PFGE). A newly developed type of pulsing is used, which causes inversion of a double-stranded DNA ladder: the distance migrated increases as the length of the DNA molecule increases. Thus, the resolution of DNA bands continues to increase during the PFGE. These two stages of electrophoresis are serially repeated. Eventually, both the short and the long DNA ends of the ladder migrate out of the gel while a selected region of the ladder undergoes progressive increase in resolution during back-and-forth migration. Improved resolution of DNA bands is achieved, without a known limit.

Chemical Fractionation↗

PubMed2000

An efficient model of an equipment loaded panel for active control design studies.

An effective investigation of alternative control strategies for the reduction of vibration levels in satellite structures requires realistic, yet efficient, structural models to simulate the dynamics of the system. These models should include the effects of the sources, receivers, supporting structure, sensors, and actuators. In this paper, a modeling technique which meets these requirements is developed and some active control strategies are briefly investigated. The particular subject of investigation is an equipment-loaded panel and the equations of motion are derived using the Lagrange-Rayleigh-Ritz (LRR) approach. The various pieces of equipment on the panel are mounted on active or passive suspensions, and resonators are used to represent the internal dynamics of the mounted equipment. Control of the panel, which transmits vibrations from sources to receivers, is by means of piezoelectric patches and the excitation consists of dynamic loads acting on the equipment enclosures and/or directly on the panel. The control objective is to minimize the displacement at an arbitrary output location. The LRR model developed is verified against one produced by using the finite-element method. Finally, some initial controller design studies are undertaken to investigate and compare the effectiveness of different control strategies (e.g., minimization at the source, along the vibration path, or at the receiver).

Algorithms↗

PubMed2000

Combined subcutaneous recombinant alpha-interferon and interleukin-2 in metastatic renal cell cancer: results of the Multicentre All Ireland Immunotherapy Study Group.

OBJECTIVE: To analyse the toxicity and efficacy of combined interferon-alpha and interleukin-2, administered subcutaneously in a general multicentre setting, as treatment for metastatic renal cell carcinoma. METHODS: Thirty-three patients with metastatic renal cell carcinoma were scheduled to receive 2 cyclical doses of subcutaneous interferon-alpha (week 1: 5 MU x 3 days) and interleukin-2 (week 2: 36 MU x 2 days, 9 MU x 3 days; weeks 3-5: 9 MU daily). Karnofsky scores ranged from 80 to 100 (median 90). Metastases occurred in multiple organs (lung 63%, retroperitoneal 39%, liver 24%). Patients were categorised according to the risk of disease progression. Treatment toxicity, therapeutic response and actuarial survival were analysed. RESULTS: All patients received recommended doses of treatment, but 6 received less than 2 cycles. Most were treated as outpatients, although hospitalisation was usual during the 1st week of a cycle. All complained of mild flu-like symptoms. Severe side effects developed in 13 patients (39%), and treatment was discontinued in 3 of these patients. No deaths occurred as a result of treatment. The overall median survival was 10 months. The overall actuarial survival rate at 3 years was 22%. On statistical analysis, actuarial survival rates were not influenced by either response to treatment or risk group category. CONCLUSION: Subcutaneously administered, combined interferon-alpha and interleukin-2 therapy achieves durable survival rates in a minority of patients with renal cell carcinoma. Toxicity is remedial, and not fatal, when subcutaneous therapy is administered by multiple medical disciplines at a variety of centres.

Carcinoma, Renal Cell↗

PubMed1999

Relationship between attitudes to health, body weight and physical activity and level of physical activity in a nationally representative sample in the European Union.

OBJECTIVE: To explore the factors that influence attitudes and beliefs about the effects of body weight and physical activity on health. DESIGN: Cross-sectional survey using a face-to-face interview-assisted questionnaire. SETTING: The survey was conducted between March and April 1997 in the 15 member states of the EU. SUBJECTS: Approximately 1000 adults aged 15 years plus from each country were selected by quota-controlled sampling; the total sample was of 15,239 persons (7162 males and 8077 females). Data were weighted by population size for each country and by age, gender and regional distribution within countries. RESULTS: Overall 27% of men and 35% of women reported not engaging in any form of recreational activity; rates were highest in those with a primary-level education (37% men, 43% women) compared with tertiary-level education (20% men, 25% women). Recreational activity levels declined with age and tended to be lowest in those who were more physically active at work. Eighteen per cent of respondents believed that physical activity was one of the two greatest influences on health; 13% mentioned body weight, 38% mentioned food, 41% mentioned smoking and 33% mentioned stress. Logistic regression was used to assess for the effects of gender, age, educational level, body mass index (BMI), smoking status, activity level and country on beliefs that body weight and physical activity influenced health. Primary-educated, overweight, ex- and non-smoking women were most likely to mention body weight as an influence; young tertiary-educated, thinner, non-smoking and active males were most likely to mention physical activity. There was wide variation across Europe in reported behaviour and beliefs, which persisted after taking account of all of the other factors in the regression model. CONCLUSIONS: Relatively few people in some countries believed body weight and physical activity were important influences on health. Many people mentioned stress and it might be possible to use this interest to motivate changes in physical activity to relieve stress. It may be important to take a more integrated approach to activity patterns that consider the role of work and recreation. Although social and demographic factors were important, after adjusting for these factors there was still wide between-country variation in reported attitudes, beliefs and behaviour. This will need to be taken into account in any activity promotion campaigns.

Adolescent↗

PubMed1999

Measurement of urinary collagen cross-links indicate response to therapy in patients with breast cancer and bone metastases.

Objective assessment of response in bone metastases from breast cancer using radiological techniques takes up to 6 months of treatment to be certain of a response, and sclerotic metastases are not evaluable. Standard serum and urinary tumour markers may not always be utilized to predict response, as they may not be elevated, and therefore may not change on treatment. The development of the urinary pyridinoline cross-link assays which measure mature bone breakdown products have been shown to be highly sensitive and specific as a measure of bone change in osteoporosis. We have measured pyridinoline (Pyr) and deoxypyridinoline (Dpyr) cross-links sequentially in 36 breast cancer patients with bone metastases, to determine if the measurement of these analytes predicts response at an earlier stage than radiological assessment. Response was assessed by UICC criteria. Seventeen women responded to hormonal therapy, whilst 19 developed progressive disease. Both Pyr and Dpyr increased sequentially in women with progressive disease with changes becoming apparent by 8 weeks (P<0.03). In responding women, cross-link levels did not change significantly. Pyr and Dpyr were more sensitive and specific than the standard serum tumour marker CA 15-3. Urinary cross-link measurements provide a novel objective method of assessing response to treatment in women with bone metastases. Initial elevated urinary cross-link markers identify patients who tend not to respond to changes in hormonal therapy.

Adult↗

PubMed1999

Use of alternative therapies among breast cancer outpatients compared with the general population.

CONTEXT: Breast cancer is the second largest cause of cancer death among women in the United States. Given the fear associated with its morbidity and mortality, patients might seek a variety of alternative treatments. No careful description of breast cancer patients' interest in or use of these therapies appears to exist. OBJECTIVE: To create a profile that describes interest in and use of a wide variety of alternative therapies available to breast cancer outpatients; to gather data concerning related issues such as the number of appointments for these therapies, their cost, and reimbursement patterns; and to compare these findings with a published profile of the general public. DESIGN: An interview gauging patients' interest in and use of alternative treatments followed by 2 questionnaires concerning (1) mental adjustment to the cancer experience and (2) personal growth in response to the encounter with cancer. SETTING: Suburban breast cancer clinic in a Midwestern university medical center. PARTICIPANTS: 112 female breast cancer outpatients. MAIN OUTCOME MEASURES: Rankings of interest in and use of alternative treatments by the patients interviewed. RESULTS: The 3 most frequently used alternative therapies were prayer (76%), exercise (38%), and spiritual healing (29%). Comparison with the general public profiles revealed that breast cancer patients more frequently used 17 specific alternative therapies. The largest increases were found in the use of prayer (51% increase), spiritual healing (25% increase), and megavitamins (23% increase). Only chiropractic was used substantially more often among the general population. CONCLUSION: Breast cancer outpatients involved in conventional treatment are more likely to use a wide range of alternative therapies than is the general public. It is likely that the mortality and morbidity associated with breast cancer motivates this increased use.

Adult↗

PubMed1998

Head-wag autotomography of the upper cervical spine in infantile torticollis.

BACKGROUND: Infants with torticollis require evaluation of the entire cervical spine for vertebral anomalies as part of the work-up, but open-mouth views to assess occiput to C2 are difficult to obtain. OBJECTIVE: To evaluate a "head wag" autotomographic technique for the frontal projection of this region. MATERIALS AND METHODS: Twenty infants under one year of age were evaluated using this technique. RESULTS: Sixteen of 20 could be adequately evaluated using this simple, low-radiation-dose procedure. CONCLUSION: For infants with torticollis in whom vertebral anomalies need to be excluded, the "head wag" technique is useful.

Cervical Vertebrae↗

PubMed1998

Prostate-specific antigen doubling times are similar in patients with recurrence after radical prostatectomy or radiotherapy: a novel analysis.

PURPOSE: Some investigators have analyzed the rate of growth of prostate cancer that has recurred after definitive radiotherapy or radical prostatectomy using serum prostate-specific antigen (PSA) doubling times (DT). We examined all PSA values in recurrent patients to determine the pattern and rate of increase in PSA after radiation therapy and radical prostatectomy. PATIENTS AND METHODS: Charts of 96 recurrent radical prostatectomy patients (mean age, 62.8 years; range, 47 to 76) and 42 recurrent radiation therapy patients (mean age, 67.2 years; range, 52 to 83) were reviewed. All available PSA values between the date of operation/radiation treatment and last follow-up evaluation or the initiation of second-line therapy are included. Rate of PSA DT was not assumed to be constant over time; it was instead allowed to vary. We use a piecewise linear random-coefficients model in time for log (PSA), which allowed different mean models for both treatments. RESULTS: The PSA DT in the first year after radiation therapy was--1.17 years, which reflects the continuous decline in PSA in the average patients during the first year after radiotherapy despite eventual biochemical progression. In contrast, the PSA DT in the radical prostatectomy group was 0.66 in the first year. In year 2, after radiation therapy, the PSA DT was lengthy at 1.82 years, significantly longer (P = .0025) than in the radical prostatectomy group (0.76 years). After year 2, there were no significant differences between the two groups (P > .05). CONCLUSION: A piecewise linear random-coefficients model enables interval analysis of PSA DT. While the PSA DT after radiation therapy and radical prostatectomy are different in the first 2 years, the rate of increase in PSA appears to be similar in the two groups after year 2, which suggests the rate of growth of cancers that recur after radiation therapy and radical prostatectomy is similar.

Aged↗

PubMed1998

The role of orchiectomy in the management of postpubertal cryptorchidism.

PURPOSE: Owing to the risk of future malignancy, many postpubertal male subjects presenting with unilateral cryptorchidism undergo orchiectomy rather than orchiopexy. We examined the incidence of spermatogenesis and carcinogenesis in whole orchiectomy specimens removed from postpubertal cryptorchid male subjects. We review the concept that orchiectomy is justifiable in these patients. MATERIALS AND METHODS: A total of 52 patients with postpubertal cryptorchidism (unilateral in 48, bilateral in 4) were retrospectively analyzed from 1984. Patient age ranged from 15 to 66 years (mean 26). Six patients presented with primary infertility (unilateral in 3, bilateral in 3). The undescended testicles were palpable in 32 cases (62%). All patients underwent unilateral orchiectomy and whole specimens were examined histologically. RESULTS: Histology showed normal spermatogenesis in only 1 orchiectomy specimen, while 15 had maturation arrest, 6 testicular agenesis and 30 seminiferous tubular atrophy and/or Sertoli-cell-only syndrome with no spermatogenesis. The location of the undescended testis was the superficial inguinal pouch in 32 cases, inguinal canal in 6 and inside the deep ring in 8. Absent spermatogenesis was significantly associated with a high level of maldescent and with increasing age. Two patients (4%) had carcinoma in situ of the testicle. Torsion of an undescended testicle occurred in 1 patient (2%). CONCLUSIONS: This analysis of cryptorchid testes in postpubertal male subjects confirms that the majority cannot contribute to fertility, have significant malignant potential and may undergo torsion. Therefore, orchiectomy remains the treatment of choice for the majority of postpubertal male subjects presenting with unilateral cryptorchidism.

Adolescent↗

PubMed1998

Developing the 'health-promoting school'--a national survey of healthy schools awards.

The concept of the 'Health Promoting School' has been widely advocated as an approach to enhancing public health through school based health promotion. In many areas 'Healthy Schools Award' schemes have been set up to support the development of this concept, but there is no information on how widespread this practice is in the UK, how standards are evaluated, and what effect Healthy Schools Awards may have on young peoples' health. This UK national survey aimed to determine the extent and nature of existing award schemes and how they were being evaluated. A postal questionnaire was sent to all 200 health promotion units in the UK; the response rate corrected for mergers of units was 78.5%. Sixty-eight respondents (51%) were involved with an award scheme and 28 (21%) were planning them. Current award schemes were mostly jointly run by the health and education sectors, encompassing 845 participating schools of which two-thirds were primary schools. The most common issues addressed were; standard chronic disease risk behaviour, the environment and health education in the national curriculum; less frequently addressed were mental health, accident prevention, staff health and developing links with the wider community. Evaluation was usually by target setting and assessment of progress over a two year period. However, evaluation was rarely external or independent, raising doubts about the standards obtained and validity of the approaches. This survey highlights the rapid growth of healthy schools award schemes and the need for wider exchange of information on good practice. In particular there is a need for more explicit and measurable standards of achievement to ensure the quality of award schemes, and further research into their effectiveness.

Adolescent↗

PubMed1997

A modeling technique for active control design studies with application to spacecraft microvibrations.

Microvibrations, at frequencies between 1 and 1000 Hz, generated by on board equipment, can propagate throughout a spacecraft structure and affect the performance of sensitive payloads. To investigate strategies to reduce these dynamic disturbances by means of active control systems, realistic yet simple structural models are necessary to represent the dynamics of the electromechanical system. In this paper a modeling technique which meets this requirement is presented, and the resulting mathematical model is used to develop some initial results on active control strategies. Attention is focused on a mass loaded panel subjected to point excitation sources, the objective being to minimize the displacement at an arbitrary output location. Piezoelectric patches acting as sensors and actuators are employed. The equations of motion are derived by using Lagrange's equation with vibration mode shapes as the Ritz functions. The number of sensors/actuators and their location is variable. The set of equations obtained is then transformed into state variables and some initial controller design studies are undertaken. These are based on standard linear systems optimal control theory where the resulting controller is implemented by a state observer. It is demonstrated that the proposed modeling technique is a feasible realistic basis for in-depth controller design/evaluation studies.

Acoustics↗

PubMed1997

Fifteen-year survival and recurrence rates after radiotherapy for localized prostate cancer.

PURPOSE: To determine 15-year survival and recurrence rates after radiotherapy for localized prostate cancer. METHODS: One hundred thirty-six patients with clinically localized prostate cancer treated from 1966 to 1974 with interstitial gold seed and external-beam irradiation were evaluated to determine the probability of recurrence and survival > or = 15 years after therapy. All patients were surgically staged with pelvic lymphadenectomy and none received hormonal therapy before relapse. RESULTS: Overall, 60 patients (44%) have never recurred, although 57% (34 of 60) of these same patients have died of causes other than prostate cancer. Local progression developed in 39% of patients and distant metastases in 42%. At 15 years, the probability of dying of prostate cancer was 33%+/-8% (% +/- 2SE) and of all causes was 72%+/-8%. In clinical stage A2 and B, 29%+/-9% of patients died of their cancer within 15 years, compared with 57%+/-21% in stage C1, while only 18%+/-8% with clinical stage A2 and B and negative lymph nodes died of cancer within this period. In contrast, the prostate cancer mortality rate at 15 years was high for patients with positive nodes regardless of the stage of the primary tumor (73% for A2 and B; 71% for C1). Patients with nodal metastases, poorly differentiated tumors, and advanced local disease all had a significantly (P < .0001) increased risk of cancer death. CONCLUSION: The cancer-specific mortality rate for patients with stage A2 and B tumors and negative nodes compares favorably with other series of patients treated with radiation therapy and > or = 15 years' follow-up evaluation. While local progression rates are high and associated with a substantial risk of prostate cancer death, many patients live with the disease and ultimately die of causes other than prostate cancer.

Adult↗