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Biomedical subjects

John Ryan

Publications and source records attributed to John Ryan.

12 recordsLinked to original sources

Evaluation of the albumin cobalt binding (ACB) assay for measurement of ischaemia-modified albumin (IMA) on the Beckman Coulter LX-20.

BACKGROUND: In the presence of ischaemia, albumin undergoes changes resulting in the formation of ischaemia-modified albumin (IMA). Increased serum concentrations of IMA have been found in patients with myocardial ischaemia. The purpose of this study was threefold: to evaluate the albumin cobalt binding (ACB) assay for measurement of IMA on the Beckman Coulter LX-20; to establish a reference range for IMA; and to investigate the relationship between IMA and total albumin concentrations. METHODS: The ACB assay was evaluated under the following headings: imprecision, accuracy and reliability. A reference range was established on a population of 81 healthy subjects. RESULTS: The within-batch coefficient of variation (CV) at IMA concentrations of 88, 99 and 120 KU/L were 1.4, 2.0 and 2.5%, respectively. The between-batch CVs at 74, 84 and 123 KU/L were 3.4, 3.3 and 3.0%, respectively. Comparison with the Cobas Mira Plus showed a mean negative bias of 7 KU/L. The 97.5th percentile established on our reference population was 110 KU/L. A significant inverse relationship was found between total serum albumin and IMA concentrations (r = -0.66, P < 0.0001). Correcting the IMA concentrations for total albumin in our reference population, using a formula devised in this study, yielded a range similar to that of uncorrected IMA. CONCLUSIONS: The ACB assay was found to have acceptable precision and performed very satisfactorily on the Beckman Coulter LX-20. A correction to measured IMA concentrations, to take into account total albumin concentrations, may need to be applied for the proper interpretation of IMA results.

Autoanalysis↗

Lack of effects of Bacillus sphaericus (Vectolex) on nontarget organisms in a mosquito-control program in southeastern Wisconsin: a 3-year study.

A 3-year study (2000-2002) in southeastern Wisconsin was conducted to assess the effects of Bacillus sphaericus applied for mosquito control on nontarget wetland invertebrates. The experimental design consisted of control and treatment sites (that were applied by helicopter with Vectolex CG), each in 2 vegetation habitat types: reed canary grass marsh (Phalaris arundinacea) and cattail marsh (Typha spp.). In each of these areas, a predetermined number of timed (30-sec) D-frame aquatic net samples containing vegetation, detritus, and invertebrates were collected 1 day before spraying and 72 h after spraying to detect for effects. We examined and compared 5 bioassessment measures to determine if there was an effect of B. sphaericus on nontarget organisms during each of the sampling years. The metrics tested were (1) mean taxa richness (the mean number of all taxa), (2) mean diversity (combines taxa richness and abundances in a summary statistic; i.e., Shannon Index [H'I]), (3) Diptera richness (minus mosquitoes) as a proportion of all other taxa richness (Diptera/others richness), (4) Diptera abundance (minus mosquitoes) as a proportion of all other invertebrate abundance (Diptera/others abundance), and (5) functional group changes in percent collector-gatherers, collector-filterers, scrapers, shredders, and predators. When Vectolex was applied during 6 treatments at the labeled dosage rate in the above habitats in Brookfield, WI, no detrimental effects to nontarget organisms could be attributed to this microbial insecticide. Much of the variation in the control vs. treatment and pre vs. post plots was attributed to factors other than the effects of B. sphaericus on nontarget organisms, such as the time of sampling, natural variation that occurs in such diverse habitats as canary grass and cattail marshes, and water depth, which varied among years.

Animals↗

SHP-1 regulates STAT6 phosphorylation and IL-4-mediated function in a cell type-specific manner.

SHP-1 has been shown to play positive and negative regulatory roles in IL-4-induced STAT6 phosphorylation and in IL-4-mediated functions. To determine whether SHP-1 can regulate STAT6 phosphorylation and IL-4-mediated functions in a cell type-specific manner in the immune system, we examined the IL-4 receptor (IL-4R) expression, STAT6 phosphorylation, and IL-4-mediated functions in CD4+ and CD8+ T cells of viable motheaten (me(v)/me(v)) and littermate control (+/-) mice. CD4+ T cells as well as CD8+ T cells from the lymph node of me(v)/me(v) and +/- mice expressed comparable levels of IL-4R. In CD4+ T cells, the loss of SHP-1 activity did not affect IL-4-induced STAT6 phosphorylation or IL-4-mediated function. In contrast, SHP-1-deficient CD8+ T cells from me(v)/me(v) mice failed to develop into IL-4-producing type-2 cytotoxic T cells (Tc2) in the presence of IL-4 despite that they showed comparable levels of STAT6 phosphorylation to that of +/- CD8+ T cells. Loss of SHP-1 activity also abolished IL-4-mediated inhibition of c-kit expression in bone marrow-derived mast cell (BMMC). Thus, our data suggest that SHP-1 may regulate IL-4-induced STAT6 phosphorylation and IL-4-mediated functions in a cell type-specific manner.

Animals↗

Acute nutmeg poisoning.

We present a case of acute nutmeg poisoning in a 16-year-old youth who had ingested the substance for recreational purposes. He developed a number of neurological symptoms and signs along with non-specific electrocardiographic changes and anti-cholinergic-type symptoms. We describe the pharmacology of nutmeg and its constituents, discuss its metabolism, and make recommendations about the management of nutmeg poisoning. Emergency staff should be aware of the effects of nutmeg, which may present in marijuana users who seek alternative substances.

Acute Disease↗

Accurate STR allele designations at the FGA and vWA loci despite primer site polymorphisms.

Polymerase chain reaction (PCR)-based STR DNA typing systems are used extensively in the field of human identification. Under optimal PCR conditions, the amplicon yield from both alleles of an STR locus is expected to be approximately equivalent. However, it is reasonable to expect that rare genomic sequence polymorphisms will co-localize with well-designed primer sets and induce allele imbalance or "dropouts". Two samples were identified in the course of genotyping thousands of individuals with AmpF/STR Profiler Plus that showed strong disparity in amplitude peak height of heterozygous peaks at the loci vWA and FGA. These samples were reamplified at reduced annealing temperature in an attempt to balance the peak heights. Nucleotide sequencing documented polymorphisms at the PCR primer binding sites of the affected alleles. The results indicate that reducing the annealing temperature to improve primer-binding efficiency at the mismatch and employing an alternative multiplex enhanced the data from both samples. Reducing annealing temperatures could provide a simple general solution to improving data quality for samples where polymorphisms are suspected to cause allele imbalance. Finally, we report on additional polymorphisms surrounding the vWA locus in a genetically diverse population.

Allelic Imbalance↗

From anchovies to sardines and back: multidecadal change in the Pacific Ocean.

In the Pacific Ocean, air and ocean temperatures, atmospheric carbon dioxide, landings of anchovies and sardines, and the productivity of coastal and open ocean ecosystems have varied over periods of about 50 years. In the mid-1970s, the Pacific changed from a cool "anchovy regime" to a warm "sardine regime." A shift back to an anchovy regime occurred in the middle to late 1990s. These large-scale, naturally occurring variations must be taken into account when considering human-induced climate change and the management of ocean living resources.

Animals↗

Editorial.

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Journal Article↗

Comparison of intraocular light scatter in carriers of choroideremia and X-linked retinitis pigmentosa.

OBJECTIVE: To compare the extent of intraocular straylight in carriers of choroideremia (CHM) and X-linked recessive retinitis pigmentosa (XLRP) to clarify further the relationship between photoreceptor cell degeneration and intraocular light scatter in retinal diseases. DESIGN: Prospective case-control study. PARTICIPANTS: Six obligate carriers of CHM, 12 obligate carriers of XLRP, and 30 age-similar control subjects with normal vision. The controls had no posterior subcapsular (PSC) lens opacities, and the carriers had minimal or no PSC lens opacities, as assessed by slit-lamp biomicroscopy. MAIN OUTCOME MEASURES: Straylight levels were measured using a van den Berg Straylightmeter. Visual acuity and Goldmann visual field area using a II/4e target were assessed for both eyes of each carrier. Electroretinogram (ERG) data were available on four of six carriers of CHM and all carriers of XLRP. The extent of retinal pigment epithelial degenerative changes was evaluated by fundus examination. RESULTS: All six carriers of CHM had typical fundus abnormalities with normal visual fields. Five of the six carriers of CHM had age-normal levels of intraocular light scatter, and one showed minimally elevated intraocular light scatter. The 12 carriers of XLRP had a spectrum of fundus abnormalities and varying severity of functional impairment as derived from visual field areas and ERG amplitudes. Seven of the 12 carriers of XLRP showed an elevated level of intraocular light scatter in at least one eye. The degree of straylight elevation above the normal mean age value was correlated significantly with both visual field area and amplitude of the maximal-intensity, dark-adapted ERG b-wave. CONCLUSIONS: The carriers of XLRP who had evidence of photoreceptor cell dysfunction (as determined by visual field loss and reduced ERG amplitudes) had increased levels of intraocular straylight, whereas the carriers of CHM, who showed fundus abnormalities alone, in the absence of demonstrable photoreceptor cell dysfunction, had normal or minimally elevated levels. This finding supports the hypothesis that the increased levels of intraocular light scatter observed in some patients with hereditary retinal degenerations result from subclinical changes in the PSC region of the lens as a consequence of photoreceptor cell degeneration.

Adult↗

Delayed neuropsychologic dysfunction after liver transplantation for acute liver failure: a matched, case-controlled study.

Although several studies have identified posttransplant neurologic sequelae in patients with acute liver failure (ALF), the effects of these sequelae on neuropsychologic functioning after transplant is unknown. This study compared neuropsychologic functioning of ALF patients with chronic liver disease patients after liver transplantation. After liver transplantation, seven ALF patients were compared with a matched control group of patients who had been transplanted for chronic liver disease. The patients were matched by gender, age (within 5 years), and time since transplantation (within 2 years). Patients completed a 2-hour battery of tests, which included measures of attention, memory, motor performance, abstract conceptualization, and visuospatial perception. There were no significant differences between the groups on measures of socioeconomic status or education. Significant differences were found on three separate tests: WAIS-III Vocabulary, WAIS-III Similarities, and WMS-III Paired Associate Learning II. Although these tests measure distinct functions (vocabulary knowledge, abstract conceptualization, and delayed verbal recall), they may be influenced by broader verbal functions, such as verbal fluency, conceptualization, and the ability to articulate ideas. When patients were asked what functions had noticeably deteriorated since transplantation, nearly all complained of memory difficulties, and there was no difference between groups. However, more ALF than chronic liver disease (CLD) patients complained of concentration difficulties. The results of this study suggest that ALF patients may experience more neuropsychologic dysfunction after transplant. Further studies are required to expand on these initial observations with the potential to improve patient care and referral to appropriate rehabilitative services.

Acute Disease↗