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Biomedical subjects

A Warren

Publications and source records attributed to A Warren.

At least 19 recordsLinked to original sources
PubMed2001

Abundance, biomass and viability of bacteria in wastewaters: impact of treatment in horizontal subsurface flow constructed wetlands.

The aims of this project were to assess bacterial populations (abundance, biomass and viability) in the influents and effluents of four constructed wetlands, and to analyse the effect of such biological treatment on these bacterial characteristics. Using the BacLight probe it was possible to determine the total abundance, the proportion of intact vs. damaged cells, and the lengths, widths and biovolumes, of bacteria in each of the samples. The reduction in bacterial concentration was higher (67%) in the wetland used for secondary treatment than in those used for tertiary treatment (15-39%). The proportion of damaged cells was higher in the influent (i.e. settled sewage) of the wetland used for secondary treatment (78%) than in the influents of those wetlands used for tertiary treatment (45-70%). This suggested that the majority of bacteria in the settled sewage were dead or damaged, and that these were removed from the wastewaters more effectively than were undamaged cells during conventional secondary treatment (in this case, using rotating biological contactors or RBCs). In each wetland, the proportion of damaged cells was higher in the influent than in the effluent, suggesting that, as with RBCs, damaged bacteria were removed more effectively within the wetland than undamaged bacteria. The majority of bacteria leaving the constructed wetlands used for tertiary treatment, and 50% of those leaving the secondary treatment wetland, were physically intact and therefore probably viable. Although there was a decrease in the abundance of total bacteria with treatment, bacterial biomass did not necessarily decrease with the treatment.

Bacteria↗
PubMed2001

Effect of bone meal (calcium phosphate) amendments on metal release from contaminated soils--a leaching column study.

Metal-contaminated soil may be remediated in situ by the formation of highly insoluble metal phosphates if an appropriate phosphorus (P) source can be found. Leaching column experiments have been carried out to assess the suitability of bone meal as such a source. Bone meal additions reduced metal release from a contaminated soil, increased soil and leachate pH and decreased soil leachate toxicity. Minimal P leaching occurred from the soil. The data are consistent with a proton consuming bone meal (calcium phosphate) dissolution reaction followed by the formation of metal phosphates. Although, no metal phosphates were observed to form using X-ray diffraction of scanning electron microscopy this could be due to their low concentration. Relatively low (1:50 bone meal:soil) concentrations of fine (90-500 microns) bone meal would appear to be an effective treatment for metal-contaminated soils.

Biological Products↗
PubMed2001

Computational analysis of Thr203 isomerization in green fluorescent protein.

Green fluorescent protein (GFP) is an extensively used fluorescent tag. Photoisomerization between two spectroscopically distinct states in wild-type GFP is responsible for its two visible absorption bands at 398 nm (A) and 475 nm (B). We have used molecular mechanics and database analysis to support the suggestion of other researchers that the anionic form of the GFP chromophore is responsible for the B absorption band, while the phenol form is responsible for band A. The anionic (-Otyr, Nimid, Glu222H) species is the only form that has a low energy pathway allowing for isomerization of Thr203 to a conformation where it stabilizes the phenolate form and is therefore the most likely species responsible for the B absorption band. The rotation of the Thr203 side-chain is restricted; this may be significant in the formation of the intermediate state which is central to the photoisomerization. Our calculations support the most commonly accepted mechanism for photoisomerization, and we have shown that the 201LSTQS205 sequence does not allow a g+ conformation for Thr203.

Computer Simulation↗
PubMed2001

Poly ADP ribose-polymerase inhibitors prevent the upregulation of ICAM-1 and E-selectin in response to Th1 cytokine stimulation.

We studied the role of poly-ADP-ribose polymerase (PARP) in the mobilization of ICAM-1, VCAM-1, and E-selectin by TNF-alpha and IL-1beta in cultured human endothelial cells. Enzyme linked immunosorbent analysis (ELISA) was used to assess if ICAM-1, VCAM-1, and E-selectin were expressed at the cell surface, and if PARP inhibition (using the selective PARP inhibitor GPI 6150) blocked the induced expression. Endothelial cell adhesion molecule expression was evaluated at 4 and at 24 h after cytokine stimulation. At 4 h ICAM-1 and E-selectin, but not VACM-1, were stimulated by both IL-1beta and TNF-alpha. Blocking PARP via GPI 6150 only affected TNF-alpha induced E-selectin expression at 4 hours. ICAM-1, VCAM-1, and E-selectin expression were all stimulated by both IL-1beta and TNF-alpha in the 24 h assays. PARP inhibition with GPI 6150 blocked the IL-1beta mediated stimulation of both ICAM-1 and E-selectin expression, and blocked TNF-alpha stimulation of ICAM-1 expression at 24 h. These experiments suggest that specific PARP inhibition may provide a novel method of controlling leukocyte dependent inflammation through the reduction of ICAM-1 and E-selectin expression in endothelial cells in response to cytokines.

Benzopyrans↗
PubMed2001

Inducible change in the behavior of resistance arteries from circulating factor in preeclampsia: an effect specific to myometrial vessels from pregnant women.

OBJECTIVE: It has previously been observed that a circulating factor or factors may be responsible for the changes in vessel behavior that are postulated to underlie the pathogenesis of preeclampsia. We wished to ascertain whether such changes in endothelial function are dependent on the vascular bed under investigation. STUDY DESIGN: Myometrial and infracolic omental vessels resistance vessels were obtained at cesarean delivery or hysterectomy. After incubation with either plasma from women with preeclampsia or plasma from normotensive pregnant women, myographic techniques were used to assess the endothelium-dependent relaxations of these vessels. RESULTS: Incubation of myometrial vessels from normotensive pregnant women with plasma from women with preeclampsia resulted in a significant reduction in endothelium-dependent relaxation, an effect that was independent of the parity of the patients from whom the vessels had been taken. Incubation of omental vessels from normotensive pregnant women and myometrial vessels from nonpregnant women with plasma from women with preeclampsia had no effect on the endothelium-dependent relaxation observed. CONCLUSIONS: This study demonstrates that the inducible changes in resistance vessel behavior are dependent on the tissue bed under investigation and on the pregnancy status of the patient.

Adult↗
PubMed2001

The preliminary characterization of a vasoactive circulating factor(s) in preeclampsia.

OBJECTIVE: The endothelium-dependent behavior of myometrial resistance vessels from women with preeclampsia differs dramatically from that of healthy pregnant women. Similar functional changes may be induced in vessels from healthy pregnant women by incubation with plasma from women with preeclampsia. STUDY DESIGN: Myometrial arterioles, obtained from healthy pregnant women at elective cesarean section, were incubated with plasma from women with preeclampsia or plasma from healthy pregnant women. Myographic techniques were used to study the endothelium-dependent relaxation to bradykinin. The effects of subjecting plasma from women with preeclampsia to heat treatment, charcoal stripping, protein extraction and digestion, and column fractionation on the inducible changes in endothelial function were likewise investigated. RESULTS: Incubation with plasma from women with preeclampsia resulted in a significant reduction in the vessel's endothelium-dependent relaxation, a change that was reversible. This effect was reduced by heat treating and charcoal stripping, maintained within a plasma protein concentrate, and completely removed by protease digestion. The vasoactive component(s) of the plasma had a molecular weight greater than 100 kd. CONCLUSIONS: Plasma of women with preeclampsia alters the endothelium-dependent relaxation of myometrial vessels. Our findings suggest that such alterations are induced by a high-molecular-weight protein/glycoprotein, with possible contributions from a hydrophobic, lipophilic factor.

Adult↗
PubMed2000

Delusions and hallucinations in Alzheimer's disease: prevalence and clinical correlates.

OBJECTIVES: The purpose of this study was to examine the frequency of delusions and hallucinations in patients with Alzheimer's disease (AD) and to investigate factors associated with each or the combination of the two. DESIGN: This was a cross-sectional, case-control study. SETTING: Neuropsychiatry and Memory Group, The Johns Hopkins University, USA. PARTICIPANTS: Three hundred and forty-two community-residing patients with probable AD according to NINCDS/ADRDA criteria were included in the study. MEASURES: Patients were assessed clinically for the presence of psychotic symptoms using the DSM-IV glossary definitions. The patients were also rated on standardized measures of cognitive impairment, depression, extrapyramidal symptoms, functional impairment and general health. RESULTS: Seventy-five (22%) AD patients had delusions only, nine (3%) had hallucinations only and 30 (9%) had both delusions and hallucinations. Hallucinations were associated with less education, African-American race, more severe dementia, longer duration of illness, falls and use of anxiolytics. Delusions were associated with older age, depression, aggression, poor general health and use of antihypertensives. Patients with both delusions and hallucinations were similar to the patients with delusions only. CONCLUSIONS: This study confirms the high prevalence of psychotic symptoms in AD patients encountered in clinical practice and suggests that individual psychotic symptoms have different associations.

Aged↗
PubMed2000

Characteristics and outcomes of dementia residents in an assisted living facility.

BACKGROUND: Assisted living (AL) is the fastest growing segment of residential long-term care in the US. At least half of the estimated 1 million AL residents have dementia or cognitive impairment, with many AL facilities offering specialized dementia services. Little research has been done on the demographics, outcomes, or clinical variables of this population. METHODS: Participants were a cohort of 144 residents admitted to the AL unit of Copper Ridge, a specialized dementia-care facility. Comparison samples included 737 patients with dementia residing in other locations (home, nursing home, and other assisted living facilities). Selected measures of cognition, behavior, medical health, and function were taken at admission to AL and at 6-month intervals. RESULTS: When compared with residents of the dementia-specialized AL facility, dementia patients at home were younger, less cognitively impaired, and less likely to exhibit wandering, delusions, or aggression. Residents of a dementia-specialized nursing home had more cognitive impairment, greater medical comorbidity, and were more dependent on caregivers. The 2-year mortality rate in the dementia-specialized AL was 23%, significantly lower than rates reported for nursing homes. Primarily due to increasing care needs, most residents in the specialized AL relocated to a nursing home after a median stay of 10.9 months. Depression, falling, and wandering were significant predictors of the transition. CONCLUSION: Dementia-specialized AL facilities occupy a unique position in the long-term care continuum that is distinct from home-care and nursing home facilities. This research is the first step toward understanding the significant dementia population residing in assisted living.

Aged↗
PubMed2000

Observations on trichodinid ectoparasites (Ciliophora: Peritricha) from the gills of maricultured molluscs in China, with descriptions of three new species of Trichodina Ehrenberg, 1838.

During surveys of the trichodinid parasites in mariculture beds off the coast of Shandong Province, China, four species of the genus Trichodina from the gills of marine molluscs were investigated and morphologically studied. Of these, three are described as new: T. ruditapicis n. sp. from Ruditapes philippinarum (Veneridae), T. scapharcae n. sp. from Scapharca subcrenata (Arcidae) and T. mactrae n. sp. from Mactra veneriformis (Mactridae). One little-known species, T. macomarum Raabe & Raabe, 1959, is redescribed from M. veneriformis. Taxonomic and morphometric data for these trichodinids based on wet silver nitrate and protargol-impregnated specimens are presented. For each of the new species, comparisons with closely related species are provided.

Animals↗
PubMed2000

Biomechanical, psychosocial, and organizational risk factors for WRMSD: population-based estimates from the Connecticut upper-extremity surveillance project (CUSP).

In a case-control study of a population-based telephone survey of 3,798 working adults, symptoms of work-related musculoskeletal disorder (WRMSD) were associated with biomechanical, psychosocial, and organizational factors. In several models, biomechanical exposures with strong associations were static postures (odds ratios [ORs] = 2.00-5.45); repeated pushing, pulling, lifting (ORs = 1.86-12.75); and repeated neck bending (ORs = 1.07-12.8). Psychosocial and organizational factors consistently retained in these models were demands (ORs = 1.26-1.59) and organizational support (ORs = 0.53-0.79). Decision latitude entered less frequently (ORs = 0.30-0.49). This research may have implications for intervention strategies. First, reducing both biomechanical and psychosocial risk may be more effective than focusing solely on engineering controls. Second, organizational culture and policy may have strong implications for WRMSD prevalence and control.

Adult↗
PubMed2000

Latex gloves use and symptoms in health care workers 1 year after implementation of a policy restricting the use of powdered gloves.

BACKGROUND: Latex sensitization related to glove use is a complex problem, and glove use policies that restrict exposure to powdered latex gloves alone may not provide adequate safety. This study explored health care workers' (HCWs') latex glove use and reports of related health symptoms 1 year after implementation of the latex glove replacement policy. METHODS: Two cross-sectional surveys. One was a population-based survey of HCWs at the institution (National Surveillance System for Hospital Health Care Workers); the second, a detailed survey of HCWs stratified by exposure to latex gloves (Latex Symptom Survey). RESULTS: The prevalence of symptoms of dermatitis reported by latex glove users was 40.3% (National Surveillance System for Hospital Health Care Workers) and 50.0% (Latex Symptom Survey). Symptom reports increased as exposure to latex gloves increased (pairs used per day, occupations with more glove use, working in higher exposure areas, more tenure, and more hours of use per day). Aerosol symptoms and urticaria related to latex glove use were reported much less frequently than were rash, chapping, itching, or redness. HCWs, even those with skin symptoms, continued to choose latex gloves in more than 80% of the cases. CONCLUSIONS: Stepwise preplacement evaluation at employee health clinics is recommended to identify and protect employees sensitized to latex. The medical community needs more understanding and education about latex gloves, latex sensitization, and available alternatives.

Academic Medical Centers↗
PubMed2000

Plasma from women with pre-eclampsia induces an in vitro alteration in the endothelium-dependent behaviour of myometrial resistance arteries.

OBJECTIVE: To compare the in vitro effect of plasma from normal pregnant women and women with pre-eclampsia on the endothelium-dependent behaviour of myometrial resistance arteries from normal pregnant women. DESIGN: An in vitro comparative study. SETTING: Nottingham City Hospital. SAMPLE: Uterine biopsy specimens were obtained from normal pregnant women delivered by elective caesarean section at term. Plasma was collected from nulliparous women with pre-eclampsia (n = 18), and from multiparous normal pregnant women (n = 18), all samples being matched for maternal age and gestation at venepuncture. Pools of plasma from women with pre-eclampsia and normal pregnant women were formed from these samples and were used in all the experiments. METHODS: Myometrial resistance vessels obtained from the uterine biopsies were incubated with normal pregnant plasma, plasma from women with pre-eclampsia, or without plasma. Wire myography was employed to study the effect of plasma on the endothelium-dependent behaviour of these vessels. RESULTS: Incubation of vessels from normal pregnant women with plasma from women with pre-eclampsia resulted in a significant reduction in endothelium-dependent relaxation, compared with vessels incubated either with plasma from normal pregnant women or without plasma. This alteration in endothelial function occurred after an incubation period of one hour and required a threshold concentration for its effect to become established. Removal of the vascular endothelium abolished these changes in vessel behaviour. There were no plasma-induced alterations in the endothelium-independent behaviour of the vascular smooth muscle. CONCLUSIONS: This study supports the hypothesis that plasma from women with pre-eclampsia is capable of altering endothelium-dependent myometrial relaxation in vessels from pregnant women.

Adult↗
PubMed2000

Vascular dementia and Alzheimer's disease: is there a difference? A comparison of symptoms by disease duration.

This study examined differences between vascular dementia (VaD) by the NINDS/AIRENS criteria and Alzheimer's disease (AD) on clinical grounds. A consecutive series of 517 patients with probable and possible VaD or AD were evaluated for cognitive, functional, and behavioral symptoms and separated into three subgroups by duration of dementia. These AD and VaD subgroups were then compared on a series of standardized clinical measures. The only consistent trends were for VaD patients to be more depressed, more functionally impaired, and less cognitively impaired within each disease duration subgroup. The authors conclude that there are few differences between clinically diagnosed VaD and AD. Subclassification of VaD into subgroups will improve the clinical utility of this nosologic entity.

Aged↗
PubMed1999

The effect of chromosomal translocations in acute leukemias: the LMO2 paradigm in transcription and development.

Two general features have emerged about genes that are activated after chromosomal translocations in acute forms of cancer. The protein products of these genes are transcription regulators and are involved in developmental processes, and it seems that the subversion of these normal functions accounts for their role in tumorigenesis. The features of the LMO family of genes, which encode LIM-domain proteins involved in T-cell acute leukemia through chromosomal translocations, typify these abnormal functions in tumorigenesis. For example, the LMO2 protein is involved in the formation of multimeric DNA-binding complexes, which may vary in composition at different stages of hematopoiesis and function to control differentiation of specific lineages. In T cells, enforced expression of Lmo2 causes aberrant protein complex formation that primarily seems to hinder the T-cell differentiation program. These observations underscore the conclusion that protein-protein interaction (in this case, through the LIM domain) is a key determinant in tumorigenesis. Furthermore, the study of chromosomal translocations as naturally occurring mutations has been informative about mechanisms in hematopoiesis as well as in tumor etiology.

Acute Disease↗
PubMed1999

Use of hematoxylin stain to enhance evaluation of heart malformations in the fetal rat.

Fresh and formalin-fixed visceral microdissection techniques are valuable tools for studying cardiac teratology in the fetal rat, but are limited by the difficulty experienced in visualizing the minute structures needing to be evaluated. This paper describes a simple and quick staining technique used to enhance the examination procedure. A hematoxylin-saline mixture applied directly on endothelial-lined surfaces of the heart at different stages during microdissection greatly improved visualization of membrane-thin structures such as the pulmonary and aortic semilunar valves, right- and left-side atrioventricular valves, and atrial and ventricular septa. Hematoxylin staining of endocardial surfaces is a useful adjunct to the standard visceral microdissection technique.

Animals↗
PubMed1999

Microbial resistance: novel screens for a contemporary problem.

Historically, natural products have been the source of a large variety of antibacterial agents. In the 1980s, no additional useful antibacterial agents were discovered, leading to the belief that most useful chemotypes from natural product sources had already been discovered. At this time, advances in biotechnology made it feasible to produce sufficient enzyme to set up cell-free screens. Chemical compound libraries and combinatorial synthesis became the source of chemical diversity for the screens. In spite of these efforts, very few new antibacterial agents have been discovered in the last decade. At Small Molecule Therapeutics, Inc., we have developed phenotype-based screens that take advantage of the natural physiology and biochemistry of the target enzymes. We have developed a screen to identify bacterial DNA gyrase and topoisomerase IV poisons. The "hits" identified in this screen are being characterized further. A second screen has also been developed against bacterial topoisomerase 1 in which compounds that cause DNA damage through their interaction with bacterial topoisomerase 1 have been identified. Three of the compounds identified in the screen inhibit DNA relaxation mediated by bacterial topoisomerase 1, induce DNA cleavage, are noncytotoxic at >10 microM, and have MICs of 4.0 microg/mL against Staphylococcus aureus.

Animals↗