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B Blackwell

Publications and source records attributed to B Blackwell.

At least 19 recordsLinked to original sources
PubMed2006

A novel gene cluster in Fusarium graminearum contains a gene that contributes to butenolide synthesis.

The development of expressed sequence tag (EST) databases, directed transformation and a sequenced genome has facilitated the functional analysis of Fusarium graminearum genes. Extensive analysis of 10,397 ESTs, derived from thirteen cDNA libraries of F. graminearum grown under diverse conditions, identified a novel cluster of eight genes (gene loci fg08077-fg08084) located within a 17kb region of genomic sequence contig 1.324. The expression of these genes is concomitantly up-regulated under growth conditions that promote mycotoxin production. Gene disruption and add-back experiments followed by metabolite analysis of the transformants indicated that one of the genes, fg08079, is involved in butenolide synthesis. The mycotoxin butenolide is produced by several Fusarium species and has been suggested, but not proven, to be associated with tall fescue toxicoses in grazing cattle. This is the first report of the identification of a gene involved in the biosynthetic pathway of butenolide.

4-Butyrolactone↗
PubMed2005

The 3rd international intercomparison on EPR tooth dosimetry: Part 1, general analysis.

The objective of the 3rd International Intercomparison on Electron Paramagnetic Resonance (EPR) Tooth Dosimetry was the evaluation of laboratories performing tooth enamel dosimetry below 300 mGy. Participants had to reconstruct the absorbed dose in tooth enamel from 11 molars, which were cut into two halves. One half of each tooth was irradiated in a 60Co beam to doses in the ranges of 30-100 mGy (5 samples), 100-300 mGy (5 samples), and 300-900 mGy (1 sample). Fourteen international laboratories participated in this intercomparison programme. A first analysis of the results and an overview of the essential features of methods applied in different laboratories are presented. The relative standard deviation of results of all methods was better than 27% for applied doses in the range of 79-704 mGy. In the analysis of the unirradiated tooth halves 8% of the samples were identified as outliers with additional absorbed dose above background dose.

Benchmarking↗
PubMed2001

The Advanced Glaucoma Intervention Study (AGIS): 10. Variability among academic glaucoma subspecialists in assessing optic disc notching.

PURPOSE: An analysis of data from the Advanced Glaucoma Intervention Study (AGIS) has found eyes reported to have partial optic disc rim notching (not to the edge) at baseline to have less risk of subsequent visual field loss than eyes with no notching. Because this is counterintuitive and because classification of notching had not been defined in the AGIS protocol, we have assessed AGIS ophthalmologists interobserver and intraobserver agreement on notching. METHODS: Fourteen glaucoma subspecialists classified notching in 26 pairs of stereoscopic disc photographs of eyes with mild to severe glaucomatous optic neuropathy. They classified images as showing either no notching, notching not to the edge, or notching to the edge. Several hours later, 10 of them classified the same images a second time. RESULTS: In an analysis of interobserver agreement, of 26 stereoscopic images, a plurality of ophthalmologists classified notching as absent in 9 (35%), as present but not to the edge in 7 (27%), and as present and not to the edge in 10 (38%). All 14 ophthalmologists (100%) agreed on the classification of 7 (27%) of the images, and 13 of the 14 ophthalmologists (93%) agreed on the classification of 4 additional images (15%). Of these 11 images with at least 93% agreement, notching was reported as absent in 3 (27%) and to the edge in 8 (73%). In the remaining 15 images, there was substantial disagreement about whether notching was present and, if so, whether it was to the edge. In an analysis of intraobserver agreement, none of the 10 ophthalmologists who completed the viewing a second time classified all eyes exactly the same as the first time, though 5 ophthalmologists made 4 or fewer reclassifications. Overall, 80% of the original classifications were reproduced on second reading. Of the initial classifications that were not reproduced, slightly more than half were first classified as having notching not to the edge. CONCLUSION: Without definitions or examples of optic disc rim notching, the glaucoma subspecialists had relatively high intraobserver agreement but were likely to disagree with each other in characterizing the degree of disc rim notching. We recommend development of a standard photographic classification of disc rim notching. The classification should be tested for inter- and intra-observer agreement.

Academic Medical Centers↗
PubMed2000

Purification and characterization of a common soil component which inhibits the polymerase chain reaction.

DNA prepared from soil usually contains a brown-tinted inhibitor of the polymerase chain reaction (PCR) which limits the sensitivity of this technique for specific detection of microorganisms. To localize the inhibitor, soil fractions were tested for their inhibitory effect on the PCR reaction. A highly inhibitory activity, sufficient to account for the inhibition typically exhibited by soil DNA, was found to be tightly associated with the soil microorganism fraction. After cell breakage, the inhibitory material became soluble, and was not separable from DNA by standard purification procedures. A method was derived by which most of the inhibitory material could be selectively solubilized from the microorganism fraction without cell breakage, using successive washes with buffers differing in EDTA concentration. This technique was used to isolate a substance with characteristics suggesting that it is the major PCR inhibitor contaminating DNA purified from soil. It was found to be an organic, water-soluble compound of high molecular weight, and was present in a variety of soil types from different locations. It was found to be distinctly different in its solubility properties from humic and fulvic acids, and also in its FT-IR and NMR spectra. It forms a complex with protein and may inhibit the PCR reaction by an interaction with Taq DNA polymerase.

Canada↗
PubMed1998

Methylphenidate in early poststroke recovery: a double-blind, placebo-controlled study.

OBJECTIVE: To determine the efficacy and safety of methylphenidate in acute stroke rehabilitation. DESIGN: A prospective, randomized, double-blind, placebo-controlled study. PATIENTS AND SETTING: Twenty-one stroke patients consecutively admitted to a community-based rehabilitation unit. INTERVENTION: Three-week treatment of methylphenidate (or placebo) in conjunction with physical therapy. Methylphenidate was started at 5mg and increased gradually to 30mg (15mg at 8:00AM and 15mg at 12:00 noon), and discontinued before discharge. MAIN OUTCOME MEASURES: Mood measures included the Hamilton Depression Rating Scale (HAM-D) and Zung Self-Rating Depression Scale (ZDS). Cognitive status was evaluated using the Mini-Mental State Exam (MMSE). Motor functioning was assessed using the Fugl-Meyer Scale (FMS) and a modified version of the Functional Independence Measure (M-FIM). All measures were administered pretreatment and weekly thereafter. Side effects were measured after each increase in dosage and weekly. RESULTS: Patients receiving methylphenidate treatment scored lower on the HAM-D (F(1,18)=5.714, p=.028), lower on the ZDS (F(1,18)=4.206, p=.055), higher on the M-FIM (F(1,18)=5.374, p=.032), and higher on the FMS (F(1,9)=4.060, p=.075) than patients receiving placebo. CONCLUSION: Methylphenidate appears to be a safe and effective intervention in early poststroke rehabilitation that may expedite recovery.

Activities of Daily Living↗
PubMed1997

Synthesis of phosphotyrosine-containing peptides using bis-(2,2,2-trichloro)ethyl groups for phosphate protection.

Suitability of bis-(2,2,2-trichloro)ethyl (Tc) groups for protection of phosphate moiety in Boc-mode synthesis of phosphotyrosine peptides is demonstrated Boc-Tyr(PO3Tc2)-OH and Fmoc-Tyr(PO3Tc2)-OH were prepared by acylating H-Tyr(PO3Tc2)-OH with (Boc)2O and Fmoc-ONSu, respectively. Phosphorus introduction was achieved by phosphorylating Boc-Tyr-OBzl with Tc phosphochloride. The Tc-phosphorus protector was found to be incompatible with the Fmoc group because the conditions of Fmoc removal (piperidine treatment) caused dephosphorylation. Complete NMR spectral assignments in the described compounds is presented. (Contribution No. 2398 from the Centre for Food and Animal Research).

Hydrocarbons, Chlorinated↗
PubMed1996

The primary care of patients who have bodily concerns.

A conceptual and clinical approach was developed as a high-quality, economically responsible alternative to the often unsatisfactory approach to patients described as somatizers or hypochondriacs. This approach encourages primary care practitioners to respond in a way that can be mutually satisfying to themselves and their patients who have bodily concerns.

Diagnosis, Differential↗
PubMed1996

What's in a name?

Explore the source record for details and available documents.

Consumer Advocacy↗
PubMed1996

Methylphenidate dosing: twice daily versus three times daily.

OBJECTIVE: To evaluate the short-term efficacy and side effects associated with two methylphenidate hydrochloride (MPH) dosing patterns. METHODS: Twenty-five boys with attention deficit hyperactivity disorder (ADHD) participated in a 5-week, triple-blind, placebo-controlled, crossover evaluation of MPH administered twice (b.i.d.) versus thrice (t.i.d.) per day (mean dose = 8.8 +/- 5 mg, .30 +/- .1 mg/kg/dose). Four dosing conditions (placebo, titration [gradual increase to target dose], b.i.d., and t.i.d.) were used. Dependent measures obtained on a weekly basis included: parent and teacher ratings of child behavior, parent-child conflicts, parent report of stimulant side effects, child self-report of mood symptoms, a sleep log, laboratory measures of attention, and actigraphic recording of sleep activity. RESULTS: All dosing conditions resulted in significant effects on ADHD symptoms when compared with baseline. Relative to placebo, t.i.d. dosing was characterized by improvement on the greatest number of behavioral measures, and both b.i.d. and t.i.d. were generally more effective than titration. Direct comparisons of b.i.d. and t.i.d. dosing revealed that t.i.d. was associated with greater improvement on the Conners Parent Rating Scale Impulsivity/Hyperactivity factor, with a similar marginally significant effect for the ADD-H Teacher Rating Scale Hyperactivity factor. The analysis of clinically significant change favored a three-times-a-day dosing schedule over placebo on both parent and teacher ratings of impulsivity/hyperactivity and attention. Compared with placebo, appetite suppression was rated, on average, as more severe in the t.i.d. and titration conditions, but not in the b.i.d. condition. However, the number of subjects who exhibited any or severe appetite suppression did not differ significantly between the b.i.d. and t.i.d. schedules. Although there was no difference in sleep duration for children on b.i.d. and t.i.d. schedules, total sleep time appeared to decrease slightly on t.i.d. relative to placebo according to both parent ratings and actigraphic assessment. There were no significant differences between b.i.d. and t.i.d. on any other side effects or sleep variables. CONCLUSIONS: For many children with ADHD, t.i.d. dosing may be optimal. There are few differences in acute side effects between b.i.d. and t.i.d. MPH dosing. The dosing schedule should be selected according to the severity and time course of ADHD symptoms rather than in anticipation of dosing schedule-related side effects.

Attention Deficit Disorder with Hyperactivity↗
PubMed1994

DNA testing and genetic counseling: truth or consequences.

Advances in medical genetics are providing a major clinical challenge to practitioners seeing patients concerned about their risk of developing either inherited disease or susceptibility to acquired disease. Popular information can easily exceed our professional ability to provide services to well-read patients who want answers with scientific certainty. The challenge also involves ethical questions regarding confidentiality and the way that results are disclosed. More often than not, the test itself becomes the focus of psychosocial expectations for the future and lifestyle of the patient and family. The behavioral consequences of disclosure of test results need to be anticipated by the caregiver to avoid adverse psychological outcomes.

DNA↗