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Publication
Journal: Journal of Neuro-Oncology
May/13/2002
Abstract
No treatment modality has been entirely successful in the management of pituitary adenomas. Although most patients with pituitary microadenomas can be cured by transsphenoidal surgery, the results are less satisfactory in macroadenomas in particular with suprasellar and/or parasellar extension. Additional treatment is then called for. Conventional fractional radiotherapy can often control tumour growth but is limited to 45-50 Gy with a very slow reduction in elevated pituitary hormones and a high incidence of pituitary insufficiency. Stereotactic radiosurgery allows the delivery of radiation with high precision to the target with low doses to the surrounding tissues permitting higher radiation doses. Gamma knife radiosurgery using photon energy with gamma beams from multiple cobalt 60 radiation sources is now used in many centers. It can be carried out in an outpatient setting with one single treatment. A more rapid normalization of pituitary hormone hypersecretion than with conventional radiation can be achieved as well as arrest of tumour growth and reduction of tumour mass. We therefore consider gamma knife radiosurgery as a valuable compliment to pituitary surgery. Long-term prospective studies are needed to evaluate the frequency of pituitary insufficiency in patients where the target area is determined with stereotactic magnetic resonance imaging (MRI).
Publication
Journal: Journal of Clinical Nursing
January/27/2011
Abstract
OBJECTIVE
This paper aims to: • Consider the major challenges to involving people with dementia in qualitative research. • Critique a process consent framework. • Demonstrate the need for nurses and researchers to explore these issues in research and practice with people with dementia. • Consider the impact of the Mental Capacity Act 2005 on research with people with dementia. To achieve its aims, the authors will draw on current literature and use examples which explores the use of life story work with people with dementia by taking a qualitative approach.
BACKGROUND
There is acceptance that researchers should consider ways of actively involving people with dementia in research as participants where appropriate to answering specific research questions. Process consent methods have been advocated as an ethical way forward in recruiting and gaining consent for people with dementia, the Mental Capacity Act offers guidance to both practitioners and researchers.
METHODS
This paper does not seek to be a comprehensive review of the current literature but is a discussion paper appraising a process consent framework against current literature and drawing on the lead author's PhD study, exploring life story work with older people with dementia.
CONCLUSIONS
The Mental Capacity Act and process consent frameworks compliment one another, and their use should be considered when researching issues affecting older people with dementia. Researchers and practitioners should work more closely to ensure that the principles of process consent are achieved. Process consent models can equally be applied to everyday nursing practice.
CONCLUSIONS
Process consent models can provide an ethical and practical framework to ensure that consent is continually assessed in people with dementia with all clinical interventions. The paper also draws on literature exploring practical ways of involving people with dementia in evaluating service delivery.
Publication
Journal: Pflugers Archiv European Journal of Physiology
July/23/2009
Abstract
Recent advances in optics, computer sciences, fluorophores, and molecular techniques allow investigators the opportunity to study dynamic events within the functioning kidney with subcellular resolution. Investigators can now use two-photon microscopy to follow several complex heterogenous processes in organs such as the kidney with high spacial and temporal resolution. Repeat determinations over time within the same animal are possible and minimize animal use and interanimal variability. Furthermore, the ability to obtain volumetric data (3D) makes quantitative 4D (time) analysis possible. Finally, use of multiple fluorophores concurrently allows for three different or interactive processes to be observed simultaneously. Therefore, this approach compliments existing molecular, biochemical, and pharmacologic techniques by advancing in vivo data analysis and interpretation to subcellular levels for molecules without the requirement for fixation. Its use in the kidney is in its infancy but offers much promise for unraveling the complex interdependent physiologic and pathophysiologic processes known to contribute to cell function and disease.
Publication
Journal: Journal of Nutrition, Health and Aging
July/24/2000
Abstract
Caloric restriction (CR), undernutrition without malnutrition, remains the only experimental paradigm that has been shown consistently to extend lifespan and slow aging in short-lived species. Decades of research, mostly in laboratory rodents, have shown that CR consistently extends lifespan, reduces or delays the onset of many age-related diseases and slows aging in many physiological systems. In recent years gerontologists interested in CR have focused on two unanswered questions. 1) What is the relevance of this nutritional paradigm to human aging? and 2) What biological mechanism(s) underlie the diverse effects of CR leading to a retardation of aging and disease?. To address the question of human relevance, researchers in the Intramural Research Program of the National Institute on Aging began a study of CR in nonhuman primates in the late 1980s. In addition to assessing the effects of CR on aging in primates, a major focus of this work relates to possible metabolic mechanisms of CR. A subsequent study at the University of Wisconsin Madison was initiated in the early 1990s. Certain aspects of experimental design differ between these two important ongoing investigations, but generally these studies compliment each other in many ways and have begun to provide much important data regarding the effects of CR in primates. Emerging data from these studies strongly support that physiological responses to CR in monkeys parallel the extensive findings reported in rodents. Lifespan data will not be available for several years, however, the remarkable consistency with rodent studies, in which lifespan extension is documented extensively, strengthens the possibility that CR will also extend lifespan in primates, perhaps including humans. This review summarizes the major findings from the primate CR studies after over a decade of research in this model.
Publication
Journal: Experimental Gerontology
August/5/2015
Abstract
OBJECTIVE
To quantify the reliability of isometric leg extension torque (LEMVC), rate of torque development (LERTD), isometric handgrip force (HGMVC) and RFD (HGRFD), isokinetic leg extension torque and power at 1.05rad·s(-1) and 3.14rad·s(-1); and explore relationships among strength, power, and balance in older men.
METHODS
Sixteen older men completed 3 isometric handgrips, 3 isometric leg extensions, and 3 isokinetic leg extensions at 1.05rad·s(-1) and 3.14rad·s(-1) during two visits. Intraclass correlation coefficients (ICCs), ICC confidence intervals (95% CI), coefficients of variation (CVs), and Pearson correlation coefficients were calculated.
RESULTS
LERTD demonstrated no reliability. The CVs for LERTD and HGRFD were ≤23.26%. HGMVC wasn't related to leg extension torque or power, or balance (r=0.14-0.47; p>0.05). However, moderate to strong relationships were found among isokinetic leg extension torque at 1.05rad·s(-1) and 3.14rad·s(-1), leg extension mean power at 1.05rad·s(-1), and functional reach (r=0.51-0.95; p≤0.05).
CONCLUSIONS
LERTD and HGRFD weren't reliable and shouldn't be used as outcome variables in older men. Handgrip strength may not be an appropriate surrogate for lower body strength, power, or balance. Instead, perhaps handgrip strength should only be used to describe upper body strength or functionality, which may compliment isokinetic assessments of lower body strength, which were reliable and related to balance.
Publication
Journal: Globalization and Health
June/8/2010
Abstract
The Bamako Call for Action on Research for Health stresses the importance of inter-disciplinary, inter-ministerial and inter-sectoral working. This challenges much of our current research and postgraduate research training in health, which mostly seeks to produce narrowly focused content specialists. We now need to compliment this type of research and research training, by offering alternative pathways that seek to create expertise, not only in specific narrow content areas, but also in the process and context of research, as well as in the interaction of these different facets of knowledge. Such an approach, developing 'integrative expertise', could greatly facilitate better research utilisation, helping policy makers and practitioners work through more evidence-based practice and across traditional research boundaries.
Publication
Journal: Journal of Structural Biology
November/20/2000
Abstract
A chimeric human-simian IgG, antigen specific for CD4, when exposed to 0.5 M SO(=)(4) containing 0.4% polyethylene glycol or Jeffamine, self-assembles into discreet, roughly spherical particles 23 nm in diameter. Increasing SO(=)(4) to 1.55 M induces the IgG particles to crystallize in either a hexagonal or a monoclinic form. From X-ray diffraction, the former crystal is of space group P622, with one IgG particle in the unit cell; thus the particle itself must have 622 point group symmetry. Both crystal forms have been imaged using atomic force microscopy. Detailed features of the duodecamer were evident, including the symmetry and a large solvent channel along the sixfold axis. The particles in some ways resemble the hexameric IgG aggregates believed to activate compliment upon antigen binding and, therefore, may have physiological relevance. Investigation of seven other IgGs of diverse origins and subclasses indicates that many, if not most, IgGs form similar particles. To our knowledge, this is the first observation of the assembly of IgG into high symmetry aggregates in the absence of antigen or their crystallization.
Publication
Journal: International Journal of Medical Informatics
March/29/2015
Abstract
OBJECTIVE
Usability testing can be used to evaluate human-computer interaction (HCI) and communication in shared decision making (SDM) for patient-provider behavioral change and behavioral contracting. Traditional evaluations of usability using scripted or mock patient scenarios with think-aloud protocol analysis provide a way to identify HCI issues. In this paper we describe the application of these methods in the evaluation of the Avoiding Diabetes Thru Action Plan Targeting (ADAPT) tool, and test the usability of the tool to support the ADAPT framework for integrated care counseling of pre-diabetes. The think-aloud protocol analysis typically does not provide an assessment of how patient-provider interactions are effected in "live" clinical workflow or whether a tool is successful. Therefore, "Near-live" clinical simulations involving applied simulation methods were used to compliment the think-aloud results. This complementary usability technique was used to test the end-user HCI and tool performance by more closely mimicking the clinical workflow and capturing interaction sequences along with assessing the functionality of computer module prototypes on clinician workflow. We expected this method to further complement and provide different usability findings as compared to think-aloud analysis. Together, this mixed method evaluation provided comprehensive and realistic feedback for iterative refinement of the ADAPT system prior to implementation.
METHODS
The study employed two phases of testing of a new interactive ADAPT tool that embedded an evidence-based shared goal setting component into primary care workflow for dealing with pre-diabetes counseling within a commercial physician office electronic health record (EHR). Phase I applied usability testing that involved "think-aloud" protocol analysis of eight primary care providers interacting with several scripted clinical scenarios. Phase II used "near-live" clinical simulations of five providers interacting with standardized trained patient actors enacting the clinical scenario of counseling for pre-diabetes, each of whom had a pedometer that recorded the number of steps taken over a week. In both phases, all sessions were audio-taped and motion screen-capture software was activated for onscreen recordings. Transcripts were coded using iterative qualitative content analysis methods.
RESULTS
In Phase I, the impact of the components and layout of ADAPT on user's Navigation, Understandability, and Workflow were associated with the largest volume of negative comments (i.e. approximately 80% of end-user commentary), while Usability and Content of ADAPT were representative of more positive than negative user commentary. The heuristic category of Usability had a positive-to-negative comment ratio of 2.1, reflecting positive perception of the usability of the tool, its functionality, and overall co-productive utilization of ADAPT. However, there were mixed perceptions about content (i.e., how the information was displayed, organized and described in the tool). In Phase II, the duration of patient encounters was approximately 10 min with all of the Patient Instructions (prescriptions) and behavioral contracting being activated at the end of each visit. Upon activation, providers accepted the pathway prescribed by the tool 100% of the time and completed all the fields in the tool in the simulation cases. Only 14% of encounter time was spent using the functionality of the ADAPT tool in terms of keystrokes and entering relevant data. The rest of the time was spent on communication and dialog to populate the patient instructions. In all cases, the interaction sequence of reviewing and discussing exercise and diet of the patient was linked to the functionality of the ADAPT tool in terms of monitoring, response-efficacy, self-efficacy, and negotiation in the patient-provider dialog. There was a change from one-way dialog to two-way dialog and negotiation that ended in a behavioral contract. This change demonstrated the tool's sequence, which supported recording current exercise and diet followed by a diet and exercise goal setting procedure to reduce the risk of diabetes onset.
CONCLUSIONS
This study demonstrated that "think-aloud" protocol analysis with "near-live" clinical simulations provided a successful usability evaluation of a new primary care pre-diabetes shared goal setting tool. Each phase of the study provided complementary observations on problems with the new onscreen tool and was used to show the influence of the ADAPT framework on the usability, workflow integration, and communication between the patient and provider. The think-aloud tests with the provider showed the tool can be used according to the ADAPT framework (exercise-to-diet behavior change and tool utilization), while the clinical simulations revealed the ADAPT framework to realistically support patient-provider communication to obtain behavioral change contract. SDM interactions and mechanisms affecting protocol-based care can be more completely captured by combining "near-live" clinical simulations with traditional "think-aloud analysis" which augments clinician utilization. More analysis is required to verify if the rich communication actions found in Phase II compliment clinical workflows.
Publication
Journal: Journal of Medical Case Reports
July/13/2011
Abstract
BACKGROUND
The increasing incidence of new diseases as well as changing features of known diseases has partly been attributed to the impact of environmental changes. As a result, there have been calls from health experts for proper surveillance and monitoring of these changes.This is a report of mopane worm allergy in a 36 year old female from the Tswana tribe in Botswana. Mopane worm, the caterpillar stage of Gonimbrasia belina moths, is a seasonal delicacy to people in many communities in southern Africa. As a result, by adulthood, many residents of these communities have had substantial exposure to the worm. Gonimbrasia belina moths belong to the Lepidoptera order of insects. Though some members of this order are known to induce contact allergy, there is no reported incidence of ingestion allergy from mopane worm. Therefore, it is important to track this case for its epidemiological significance and to alert both clinicians and the vulnerable public on the incidence of mopane worm allergy in this region.
METHODS
This is a case of a 36 year old woman from the Tswana ethnic group in Botswana, who was diagnosed with food allergy. She presented with itchy skin rash, facial swelling, and mild hypotension after eating mopane worm. She had no previous history of allergic reaction following contact or ingestion of mopane worm and had no atopic illness in the past. She was treated and her symptoms resolved after 4 days.
CONCLUSIONS
The proper management of allergy involves patients' avoidance and clinicians' predictability. Though hypothetical, this report is expected to sensitize clinicians to anticipate and properly manage subsequent occurrence, as well as educate the public in these communities. In addition, tracking new disease patterns, with relationship to environmental changes, will compliment existing evidence in validating the importance of proper environmental surveillance and management.
Publication
Journal: Journal of Affective Disorders
December/11/2013
Abstract
BACKGROUND
Clinical decision rules have been developed to help identify patients at high risk of repeating deliberate self-harm actions. The objective of this study was to prospectively validate the clinical decision rules', Södersjukhuset Self-Harm Rule and Manchester Self-Harm Rule, ability to predict repetition of deliberate self-harm (DSH).
METHODS
A consecutive series of 325 patients attending two large emergency departments in Stockholm, Sweden due to DSH were included and followed for six months. Predictive factors were collected from hospital charts at the emergency department. A nationwide register-based follow-up of new DSH within six months was used. We calculated the sensitivity and specificity to evaluate the different decision rules' ability to identify repetition of DSH. Main outcome measure repeated DSH within six months.
RESULTS
The cumulative incidence for patients repeating within six months was 24.6% (95% CI: 19.9-29.3). Application of Södersjukhuset Self-Harm Rule yielded a sensitivity of 89% (95%CI: 79.2-94.4) and a specificity of 11% (95%CI: 7.9-16.2). Application of Manchester Self-Harm Rule to our material yielded a sensitivity of 94% (95%CI: 85.4-97.7) and a specificity of 18% (95%CI: 13.8-23.9).
CONCLUSIONS
If data regarding predictive factors were missing it was not possible to investigate this further and in the statistical analysis missing data was classified as no. This would imply that the predicted risks may be underestimated.
CONCLUSIONS
Clinical decision rules could be used as a compliment providing important additional information regarding risk of repetition in an ED setting when focusing on high sensitivity.
Publication
Journal: Anaesthesia
December/5/2000
Abstract
The most recent edition of the Acute Physiology and Chronic Health Evaluation provides a prediction of intensive care unit length of stay in addition to the probability of hospital mortality. Intensive care length of stay is an important determinant of intensive care costs and may be an important indicator of quality of care. Data were collected from 22 Scottish intensive care units over a 2-year period to allow comparison of actual intensive care unit length of stay with that predicted by the Acute Physiology and Chronic Health Evaluation III system. Correlation between actual and predicted stay for individual patients was poor. However, performance of the model for patients, grouped either by predicted length of stay or by intensive care unit, indicated that the model stratified patient groups appropriately while demonstrating a consistent bias. Length of stay in Scottish intensive care units was found to be consistently lower than that predicted by a model which is based on intensive care practice in the USA. Variations in severity of illness in intensive care unit populations cannot readily explain differences in intensive care unit length of stay. The availability of a model capable of predicting length of intensive care stay, based on data reflecting practice in the UK, would compliment current methods of assessing effectiveness of intensive care.
Publication
Journal: Journal of Neuroscience Methods
September/29/2003
Abstract
Study of the cellular and molecular consequences of steroid hormone action in the serotonin neural system will provide new avenues for pharmacotherapeutic intervention in mental illness related to reproductive function. However, it is difficult to probe intracellular mechanisms with whole animal models. We sought the steroid receptor compliment and estrogen response of two rat serotonin cell lines in order to determine if they could be of future assistance in this matter. Immunohistochemistry with a panel of antibodies, RT-PCR and a serotonin ELISA were utilized to characterize the RN46A-V1 cells (herein called RN46A), and the subclone RN46A-B14 (herein called B14) that is stably transfected with brain derived neurotrophic factor (BDNF). RN46A and B14 cells express estrogen receptor beta (ERbeta), androgen receptors (AR) and nuclear factor kappa B (NFkappaB) but not estrogen receptor alpha (ERalpha) or progestin receptors (PR). RT-PCR confirmed the presence of ERbeta and the absence of ERalpha and PR in both cell lines. B14 cells contain more immunodetectable BDNF and serotonin than the RN46A parent line. In addition, immunofluorescence for the serotonin reuptake transporter (SERT) was observed in the cell body region of undifferentiated B14 cells. After differentiation at a nonpermissive temperature, SERT immunostaining was observed in both the cell body region and along the extent of the axons. Serotonin content as determined by ELISA was higher in B14 than RN46A cells. Estrogen (0.1 and 1.0 nM) stimulated serotonin in the B14 cells in serum free medium. In summary, the RN46A cells and the B14 subclone contain the same compliment of nuclear steroid receptors as rat raphe serotonin neurons and thus may provide a convenient in vitro model for study of intracellular mechanisms of action of steroid hormones in the context of a serotonin neuron.
Publication
Journal: Journal of Experimental Biology
May/23/2007
Abstract
Mosquito larvae are found in diverse aquatic habitats ranging from freshwater to hypersaline water and must often deal with rapid changes in habitat salinity. We transferred larvae of Aedes aegypti from freshwater to 30% seawater, or vice versa, and measured the time course of changes in their hemolymph ion concentrations, using ion-selective microelectrodes. We also reported the Michaelis-Menten kinetics of Na(+) and Cl(-) transport by the anal papillae for the first time using the scanning ion-selective electrode technique (SIET). Hemolymph concentrations of Na(+), Cl(-) and H(+) increased within 6 h, when larvae were transferred from freshwater to seawater and decreased within 6 h, when transferred from seawater to freshwater. Kinetic parameters for Na(+) and Cl(-) transport by the anal papillae were altered after only 5 h following transfer between freshwater (FW) and 30% seawater (30%SW). The J(max) (maximum transport rate) for both ions decreased when larvae were transferred to 30%SW, whereas the K(t) (a measure of transporter affinity) increased for Na(+) transport but was unaltered for Cl(-) transport, suggesting that Na(+) and Cl(-) uptake are independent. Data reveal significant changes in ion transport by the anal papillae of mosquito larvae when they are faced with changes in external salinity such that Na(+) and Cl(-) uptake decrease in higher salinity. The alterations in Na(+) and Cl(-) uptake may be a consequence of changes in hemolymph ion levels when larvae encounter altered salinity. The rapid changes in ion transport described here compliment the previously observed long term alterations in the morphology and ultrastructure of the anal papillae.
Publication
Journal: Journal of Chemical Physics
February/6/2012
Abstract
Proton-driven spin diffusion (PDSD) experiments in rotating solids have received a great deal of attention as a potential source of distance constraints in large biomolecules. However, the quantitative relationship between the molecular structure and observed spin diffusion has remained obscure due to the lack of an accurate theoretical description of the spin dynamics in these experiments. We start with presenting a detailed relaxation theory of PDSD in rotating solids that provides such a description. The theory applies to both conventional and radio-frequency-assisted PDSD experiments and extends to the non-Markovian regime to include such phenomena as rotational resonance (R(2)). The basic kinetic equation of the theory in the non-Markovian regime has the form of a memory function equation, with the role of the memory function played by the correlation function. The key assumption used in the derivation of this equation expresses the intuitive notion of the irreversible dissipation of coherences in macroscopic systems. Accurate expressions for the correlation functions and for the spin diffusion constants are given. The theory predicts that the spin diffusion constants governing the multi-site PDSD can be approximated by the constants observed in the two-site diffusion. Direct numerical simulations of PDSD dynamics via reversible Liouville-von Neumann equation are presented to support and compliment the theory. Remarkably, an exponential decay of the difference magnetization can be observed in such simulations in systems consisting of only 12 spins. This is a unique example of a real physical system whose typically macroscopic and apparently irreversible behavior can be traced via reversible microscopic dynamics. An accurate value for the spin diffusion constant can be usually obtained through direct simulations of PDSD in systems consisting of two (13)C nuclei and about ten (1)H nuclei from their nearest environment. Spin diffusion constants computed by this method are in excellent agreement with the spin diffusion constants obtained through equations given by the relaxation theory of PDSD. The constants resulting from these two approaches were also in excellent agreement with the results of 2D rotary resonance recoupling proton-driven spin diffusion (R(3)-PDSD) experiments performed in three model compounds, where magnetization exchange occurred over distances up to 4.9 Å. With the methodology presented, highly accurate internuclear distances can be extracted from such data. Relayed transfer of magnetization between distant nuclei appears to be the main (and apparently resolvable) source of uncertainty in such measurements. The non-Markovian kinetic equation was applied to the analysis of the R(2) spin dynamics. The conventional semi-phenomenological treatment of relxation in R(2) has been shown to be equivalent to the assumption of the Lorentzian spectral density function in the relaxatoin theory of PDSD. As this assumption is a poor approximation in real physical systems, the conventional R(2) treatment is likely to carry a significant model error that has not been recognized previously. The relaxation theory of PDSD appears to provide an accurate, parameter-free alternative. Predictions of this theory agreed well with the full quantum mechanical simulations of the R(2) dynamics in the few simple model systems we considered.
Publication
Journal: BMC Public Health
October/22/2017
Abstract
HIV testing has seen a rapid evolution over the last decade with multiple modalities now in use globally. In recent years HIV self-testing (HIVST) has been legalised in the UK paving the way for further expansion of testing. Interventions are delivered in particular social contexts which shape uptake. It is therefore important to understand how novel interventions are likely to be received by their intended users. This study aims to understand how HIVST compliments existing testing strategies considered or adopted by men who have sex with men (MSM). We do this by analysing normative discourses surrounding HIV testing and their perceptions of HIVST's potential future roles.
Six focus group discussions (FGDs) were conducted with 47 MSM in London, Manchester and Plymouth. One focus group included only MSM who reported higher risk behaviours and one with those who had never tested for HIV. Data were analysed through a thematic framework analysis.
Three main narratives for testing for HIV were identified: (i) testing in response to a specific risk event; (ii) as reassurance when there was a small amount of doubt or anxiety related to HIV; and (iii) in response to social norms perpetuated through peers, HIV community groups and the medical establishment to test regularly for HIV. HIVST had limited utility for men when testing in response to specific risk events except in the case of significant structural barriers to other testing opportunities. HIVST was considered to have utility when seeking reassurance, and was thought to be very useful when testing to satisfy the needs and expectations of others around regular testing. There was some ambivalence about the incursion of a clinical intervention into the home.
HIVST following risk events will likely be limited to those for whom existing service provision is insufficient to meet immediate needs based on structural or personal barriers to testing. Obligations of biological citizenship are central to MSM's understanding of the utility of HIVST. In the context of discourses of biocitizenship, men perceive HIVST to have dual roles: firstly as a tool to manage (mild) anxiety around one's HIV status based on an acknowledgment of HIV vulnerability arising from being homosexually active. Secondly, HIVST is useful in complying with social norms and meeting the perceived demands of biomedicine.
Publication
Journal: Molecular and Biochemical Parasitology
October/22/1997
Abstract
Pyridoxal kinase catalyzes the ATP-dependent phosphorylation of vitamin B6, generating pyridoxal-5'-phosphate, an important cofactor for many enzymatic reactions. Pyridoxal kinase was purified 4300-fold to homogeneity from Trypanosoma brucei and peptides generated by proteolysis were subjected to amino acid sequence analysis. The peptide sequence information was used to generate a partial clone of T. brucei pyridoxal kinase by polymerase chain reaction (PCR), which in turn was used to screen a T. brucei genomic library for a full length clone. The 903-bp gene was sequenced and found to encode a 300-amino acid protein. The deduced amino acid sequence contains all of the peptide sequences obtained from the proteolytic cleavage of the native enzyme and shares 28% sequence identity with a putative Escherichia coli pyridoxal kinase, identified for its ability to compliment pyridoxal kinase deficient cells. The T. brucei pyridoxal kinase gene was expressed in E. coli and the purified enzyme was found to have pyridoxal kinase activity, confirming that this gene encodes the functional T. brucei enzyme. Native and recombinant pyridoxal kinase have a monomer molecular weight of 37 kDa by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and are dimers in solution. Native T. brucei pyridoxal kinase catalyzes the phosphorylation of pyridoxal with a specific activity of 990 nmol min(-1) per mg and apparent Km values for pyridoxal and ATP of 22 and 9 microM. respectively. Substrate inhibition is observed for pyridoxal. Similar results were obtained for the recombinant enzyme.
Publication
Journal: Public Health Reports
January/26/1978
Abstract
Simulated addict urine samples containing drugs were sent to collaborating hospital administrators and officials of methadone centers, who then forwarded the samples to their supporting laboratories as though they were ordinary specimens from patients. The laboratories, which were already participating in the proficiency testing program of the Center for Disease Control, received the identical test samples in the mail as part of a regular Center for Disease Control proficiency testing program. Most of the laboratories performed acceptably with the mail-distributed samples, but many performed poorly when the identical samples were sent to them as if they were specimens from patients. Because of the limitations of proficiency testing involving mail-distribution samples and the impracticality of extensive testing with blind samples on a national level, the Center for Disease Control proposes to compliment its regular proficiency testing program with a monitored, onsite program of performance evaluation.
Publication
Journal: Journal of Cellular Physiology
September/28/1988
Abstract
The stimulation of DNA synthesis by epidermal growth factor (EGF) has been studied for a cell line having properties useful for investigating the mechanism of action of EGF in epithelial cell populations. These studies employ a mouse keratinocyte cell line (MK), isolated by Weissman and Aaronson (1983), which is stringently dependent on exogenous EGF for growth in serum containing medium. The studies reported here characterize the compliment of EGR receptors present on the surface of MK cells and demonstrate the regulatory influence of other hormones on the capacity of EGF to stimulate DNA synthesis. Up-regulated MK cells contain approximately 22,000 EGF receptors per cell, but when the cells are grown in the presence of EGF the receptor number is reduced to about 4,000. It is estimated that only a small number of high-affinity receptors (less than 500) are required for EGF-dependent cell proliferation. In contrast to its action in fibroblastic cells, dexamethasone is a strong inhibitor of EGF-stimulated DNA synthesis of MK cells. Insulin at high concentrations, or insulin-like growth factors I or II (IGF-I, IGF-II) at physiological concentrations, synergistically enhance the EGF response. Interestingly, insulin or IGF-I or II are also able to reverse most of the dexamethasone inhibition of DNA synthesis. Transforming growth factor-beta (TGF-beta) inhibits, in reversible manner, the EGF stimulation of DNA synthesis and this inhibition is not overcome by insulin. TGF-beta receptors have been measured in MK cells and Scatchard analysis indicates approximately 20,000 receptors per cell. None of the modulatory hormones (insulin, dexamethasone, TGF-beta) significantly altered 125I-EGF binding characteristics in MK cells, suggesting a point of action distal to 125I-EGF binding.
Publication
Journal: BMC Cancer
April/30/2007
Abstract
BACKGROUND
Shared Pathology Informatics Network (SPIN) is a tissue resource initiative that utilizes clinical reports of the vast amount of paraffin-embedded tissues routinely stored by medical centers. SPIN has an informatics component (sending tissue-related queries to multiple institutions via the internet) and a service component (providing histopathologically annotated tissue specimens for medical research). This paper examines if tissue blocks, identified by localized computer searches at participating institutions, can be retrieved in adequate quantity and quality to support medical researchers.
METHODS
Four centers evaluated pathology reports (1990-2005) for common and rare tumors to determine the percentage of cases where suitable tissue blocks with tumor were available. Each site generated a list of 100 common tumor cases (25 cases each of breast adenocarcinoma, colonic adenocarcinoma, lung squamous carcinoma, and prostate adenocarcinoma) and 100 rare tumor cases (25 cases each of adrenal cortical carcinoma, gastro-intestinal stromal tumor [GIST], adenoid cystic carcinoma, and mycosis fungoides) using a combination of Tumor Registry, laboratory information system (LIS) and/or SPIN-related tools. Pathologists identified the slides/blocks with tumor and noted first 3 slides with largest tumor and availability of the corresponding block.
RESULTS
Common tumors cases (n = 400), the institutional retrieval rates (all blocks) were 83% (A), 95% (B), 80% (C), and 98% (D). Retrieval rate (tumor blocks) from all centers for common tumors was 73% with mean largest tumor size of 1.49 cm; retrieval (tumor blocks) was highest-lung (84%) and lowest-prostate (54%). Rare tumors cases (n = 400), each institution's retrieval rates (all blocks) were 78% (A), 73% (B), 67% (C), and 84% (D). Retrieval rate (tumor blocks) from all centers for rare tumors was 66% with mean largest tumor size of 1.56 cm; retrieval (tumor blocks) was highest for GIST (72%) and lowest for adenoid cystic carcinoma (58%).
CONCLUSIONS
Assessment shows availability and quality of archival tissue blocks that are retrievable and associated electronic data that can be of value for researchers. This study serves to compliment the data from which uniform use of the SPIN query tools by all four centers will be measured to assure and highlight the usefulness of archival material for obtaining tumor tissues for research.
Publication
Journal: Glycobiology
August/10/2004
Publication
Journal: Social Science and Medicine
August/15/1995
Abstract
A qualitative study into the health seeking behaviour of caretakers in response to ARI in children under five years of age was conducted in the province of Bohol, the Philippines. The study was designed to compliment survey data generated from a long running ARI intervention project, specifically to explain behaviours identified as problematic by the project. Results indicate the importance of folk diagnosis as a basis for selection of first resort for care in the management of childhood ARI. A cultural category, piang, was identified as a major factor influencing health seeking behaviour and delay in consulting the biomedical system where serious ARI exists. In addition, caretakers' financial situation and social contacts are important in their decision to seek biomedical assistance and are often implicated in delay in presentation and acting upon referral to hospital.
Publication
Journal: Growth Hormone and IGF Research
November/12/2007
Abstract
BACKGROUND
Erythropoietin (Epo) receptors are widely expressed in the small bowel of neonatal rats and evidence suggests Epo has important trophic effects in developing bowel.
OBJECTIVE
To compliment in vitro data, we directly examine in vivo the hypotheses that systemic Epo treatment can promote cell division and enterocyte migration, and arrest apoptosis in the ileum of neonatal rats.
METHODS
Epo (5000 U/kg s.c.) or vehicle treatments were given to one week old Sprague-Dawley rats (n = 86) along with timed injections of the thymidine analog 5-bromo-2-deoxyuridine (BrdU, 50mg/kg s.c.) to label DNA synthesis and track newly proliferating cells. To characterize the time course of effects, animals were killed at scheduled times from 30 min to 24 h after treatment. BrdU-containing cells were immunostained and counted in intestinal crypts, villi, and muscle wall of ileum. Effects of Epo on apoptosis were analyzed by TUNEL staining. Calibrated measurements were made to determine the density or relative proportion of BrdU- and TUNEL-positive cells.
RESULTS
Systemic high-dose Epo promoted cell division in intestinal smooth muscle and enterocytes, stimulated migration of intestinal epithelial cells, and arrested apoptosis of enterocytes at the villous tips.
CONCLUSIONS
These data provide in vivo evidence that Epo functions trophically in developing intestine tissues.
Publication
Journal: Photosynthesis Research
December/5/2013
Abstract
The pigment composition of the light-harvesting complexes of Photosystem II (LHC II) has been determined for lettuce (Lactuca sativa). In common with other members of the composite, the photosynthetic tissues of this species may contain large amounts of the carotenoid lactucaxanthin (ε, ε-carotene-3,3'-diol) in addition to their normal compliment of carotenoids. The occurrence and distribution of lactucaxanthin in LHC II has been examined using isoelectric focusing of BBY particles followed by reversed-phase HPLC analysis of the pigments. The major carotenoids detected in LHC IIb, LHC IIa (CP29) and LHC IIc (CP26) purified from dark-adapted lettuce were lutein, violaxanthin, neoxanthin and lactucaxanthin. Lactucaxanthin has been shown to be a major component of PS II, accounting for ∼26% of total xanthophyll in both LHC IIb (∼23% total xanthophyll) and in the minor complexes (12-16%). In this study, LHC IIb was clearly resolved into four bands and their carotenoid composition determined. These four bands proved to be very similar in their pigment content and composition, although the relative amounts of neoxanthin and lutein in particular were found to increase from bands 1 to 4 (i.e. with increasing electrophoretic mobility). The operation of the xanthophyll cycle has also been examined in the LHC of L. sativa following light treatment. The conversion efficiency for violaxanthin→zeaxanthin was nearly identical for each light-harvesting complex examined at 58-61%. Nearly half of the zeaxanthin formed in PS II was associated with LHC IIb, although the molar ratio of zeaxanthin:chlorophyll a was highest in the minor LHC.
Publication
Journal: European Journal of Neuroscience
June/30/1999
Abstract
The patterns of gamma-aminobutyric acid type A (GABAA) receptor subunit gene expression in the brain are complex. For example, mouse hippocampal dentate granule cells express many subunit genes, whereas adult cerebellar granule cells, which may share differentiation mechanisms, have a smaller compliment and uniquely express the alpha6 subunit gene. To see how the alpha6 expression component arises, i.e. if intrinsically or environmentally specified, we used a mouse line (Deltaalpha6lacZ) with a beta-galactosidase reporter inserted into the alpha6 gene. Precursor cells from postnatal day 1 Deltaalpha6lacZ cerebellum were transplanted to the adult hippocampus and cerebellum of wild-type mice; 4 weeks after transplantation, Deltaalpha6lacZ cells expressed alpha6-lacZ in the hippocampus, amygdala and cerebellum. Thus, different adult environments support both the development and maintenance of alpha6 gene expression from cerebellar granule cell precursors. Establishing alpha6 gene expression is not likely to require specific patterns of neurotransmitter innervation or other factors present only in the developing brain; instead, alpha6 expression can be timed and maintained autonomously.
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