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T Johnson

Publications and source records attributed to T Johnson.

285 records · Page 16Linked to original sources
PubMedDate not supplied

Evaluation of right subphrenic fluid collections with emission computed tomography: an experimental study.

An animal model to study subphrenic fluid collections is presented. Performance of single photon emission computed tomography (SPECT) for detection of subphrenic fluid collections was compared to that of liver-lung scintigraphy and transmission computed tomography (TCT). TCT detected a water volume of 25 ml in the right subphrenic space. This volume was barely seen using SPECT and not detectable on scintigraphy. Differences in performance of the three imaging modalities are discussed.

Animals↗
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A consensus amino-acid sequence repeat in Torpedo and mammalian Ca2+-dependent membrane-binding proteins.

A group of calcium-binding proteins which bind to biomembranes has recently been identified in widely different cells and tissues (refs 1-7, reviewed in ref. 8). Three of these proteins (p70, p36 and p32.5) cross-react with antiserum to calelectrin, a Ca2+-binding protein (relative molecular mass 34,000 (34K] from the ray Torpedo marmorata, giving rise to their designation as calelectrin-related proteins. We now report that calelectrin, p36 and p32.5 contain a 17-amino-acid consensus sequence which is conserved and present in multiple copies. We suggest that this sequence may be common to other members of this new group of Ca2+-binding proteins and may underlie their unusual mode of combination with biomembranes.

Amino Acid Sequence↗
PubMedDate not supplied

Prediction of hourly microenvironmental concentrations of fine particles based on measurements obtained from the Baltimore scripted activity study.

Researchers have developed a variety of computer-based models to estimate population exposure to air pollution. These models typically estimate exposures by simulating the movement of specific population groups through defined microenvironments. During the summer of 1998 and winter of 1999, researchers with the Harvard School of Public Health (HSPH) conducted a field study in Baltimore, MD, to acquire data for improving microenvironmental models. Using a special roll-around instrument system, a technician measured 1- and 12-h pollutant concentrations while engaging in scripted sequences of activities typical of retirees. Each scripted activity assigned the technician to a geographic location and to a microenvironment. The technician recorded special conditions associated with each activity (e.g., open windows, environmental tobacco smoke) in a real-time diary. Data on ambient pollutant levels, temperature, and other potential explanatory factors were also collected. Eleven pollutants were measured by the roll-around instrument system, including particulate matter with an aerodynamic diameter less than 2.5 microm (PM2.5), ozone, carbon monoxide, and benzene. This article presents the results of statistical analyses performed solely on the 1-h PM2.5 data measured by a DustTrak monitor, which ranged from 1.5 to 444.8 microg/m3 with a median value of 14.6 microg/m3. Results of stepwise linear regression (SLR) suggest that PM2.5 exposure is significantly increased by passive smoking, high ambient PM2.5 concentrations reported by fixed-site monitors, food preparation, charcoal grills, car travel, outdoor roadside locations, and high humidity. Analysts should explicitly represent the effects of these parameters within any model developed to estimate population exposure to PM2.5. In a related study, a panel of volunteer retirees each carried a personal PM2.5 monitor and a real-time diary for nominal 24-h sampling periods as they engaged in normal daily activities. A regression equation derived from SLR analysis of the scripted activity database was applied to eight subject-days of diary data provided by the volunteer seniors to produce estimates of PM2.5 exposure for each event documented in each diary. The event-specific exposure estimates were then averaged over all events in each sampling period to produce nominal 24-h average exposure estimates. The absolute difference between the estimate obtained from the regression equation and the corresponding personal monitor measurement averaged 13%. The fixed-site monitors generally provided poorer estimates of exposure; the absolute differences for the Old Town and Clifton Park monitors averaged 26.7% and 19.5%, respectively, of the personal monitor values.

Air Pollutants↗
PubMedDate not supplied

The use and evaluation of 2 + 2 photoaddition in immobilization of oligonucleotides on a three dimensional hydrogel matrix.

Photochemical attachment of synthetic oligonucleotides on the three dimensional surface of a polyacrylamide based hydrogel was used in the specific detection of target oligonucleotides. Covalent attachment of the oligonucleotide to the hydrogel was mediated by the incorporation of a 2 + 2 photo-attachable functional group in both the hydrogel and the oligonucleotide probe. Expression and SNP assays were used to evaluate this platform.

Acrylic Resins↗
PubMedDate not supplied

Malignant rhabdoid tumor of the kidney presenting as intraocular metastasis.

A newborn infant presented with intraocular tumor that was clinically diagnosed as retinoblastoma and treated by exenteration of the globe. Within a few weeks however, a large abdominal mass was noted, which was found to involve the left kidney and right lobe of liver. Pathologic evaluation of the intraocular mass as well as fine-needle aspiration biopsy of the abdominal mass revealed features of malignant rhabdoid tumor. To our knowledge this is the first case of malignant rhabdoid tumor of the kidney with such an unusual clinical presentation.

Biopsy, Needle↗
PubMedDate not supplied

Functional health pattern assessment on-line. Lessons learned.

Assessment of patient care needs is the foundation for planning patient care and documenting the nursing process to enhance the nurse's ability to coordinate care, plan discharges effectively, and provide appropriate patient/family education. An on-line assessment module in the hospital clinical information system was implemented. This module uses Gordon's Functional Health Pattern Assessment as the foundation for the professional nursing documentation system in this academic, health science center. The article provides a description of the design of the pathways for the on-line assessment, analysis of the design, benefits of using the on-line assessment, and lessons learned from the design and implementation of the pathways.

Activities of Daily Living↗
PubMedDate not supplied

Antibiotic susceptibility patterns and plasmid profile of Helicobacter isolates from Nigeria.

Antibiotic susceptibility testing and plasmid screening of 50 local isolates of Campylobacter coli and Campylobacter jejuni were done. All isolates were sensitive to ofloxacin but were resistant to ampicillin, cloxacillin, penicillin, streptomycin and aztreonam. A large number of isolates were sensitive to nalidixic acid (96%), ceftriaxone (96%) and chloramphenicol (86%). It is noteworthy that nine (18%) of the isolates were resistant to each of erythromycin, 15 (30%) were found to harbour plasmid DNA ranging in sizes from 2.0 to 45 megadalton. Resistance to tetracycline in one isolate was associated with the carriage of a 45-megadalton plasmid.

Animals↗
PubMedDate not supplied

On change.

Explore the source record for details and available documents.

Occupational Therapy↗
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Roles of electrospray mass spectrometry, counterion distribution monitoring and N-(2-hydroxy-4-methoxybenzyl) backbone protection in peptide synthesis.

The synthesis of a 36-residue fragment of HIV integrase by standard Fmoc-polyamide chemistry was unsuccessful (Trt-protected Cys) or difficult (Acm-protected Cys); after 10-12 couplings, deprotection became hindered and a major portion (30%-50%) of the growing peptide chains became inaccessible to reagents. The synthesis was repeated using N-(2-hydroxy-4-methoxybenzyl) (Hmb) backbone protection at two strategic positions in the sequence, and Acm protection of Cys. The synthesis was trouble-free and progressed smoothly to completion. Electrospray mass spectrometric analysis at each step of the cleavage and purification showed that Hmb groups become O-acetylated during treatment of the peptide with acetic anhydride in the presence of tertiary base. The acetylated Hmb was refractory to cleavage with TFA/scavenger mixtures but could be readily removed following deacetylation with piperidine. The target peptide was purified to > 98% purity and an overall yield of 15%.

Amino Acid Sequence↗
PubMedDate not supplied

Continuous-flow solid (gel)-phase peptide synthesis using unsupported ultrahigh-load polymers: Fmoc/t-butyl strategy.

The technique of continuous-flow solid-phase peptide synthesis using unsupported polymers has been extended to cover the use of N alpha-Fmoc protected amino acids. This approach to peptide synthesis uses (but is not limited to) a phenolic bead-form polymer at 5 mmol g-1 loading. The success of the technique is based upon "layered displacement" to efficiently remove spent reagents and washing solutions from within the flow reactor under low pressure conditions. This system has been successfully employed in synthesizing the test peptides, [Leu5]-enkephalin, neurotensin and the notoriously difficult decapeptide sequence (65-74) of the acyl carrier protein.

Acyl Carrier Protein↗
PubMedDate not supplied

Conformational studies on beta-amyloid protein carboxy-terminal region (residues 34-42): strategic use of amide backbone protection as a structural probe.

Analogues of beta-amyloid (32-42) peptide, containing N-(2-hydroxy-4-methoxybenzyl) (Hmb) amide backbone substitutions at various positions have been prepared using fluoren-9-ylmethoxycarbonyl (Fmoc)-polyamide based solid phase peptide synthesis. On-line N alpha-Fmoc deprotection monitoring during assembly exhibited hindered release in the native and beta A(34-42, (Hmb)Gly38) analogue syntheses. No such hindrance was observed during the synthesis of beta A(34-42, (Hmb)Gly37) nor beta A(34-42, (Hmb)Val36). However, the latter contained an exceptionally slow coupling reaction. Cleaved peptides were analysed for solubility in a variety of solvents and insoluble pellets tested for congophilic staining. X-ray analysis of Fmoc (and H-) beta A(34-42) and the corresponding (Hmb)Gly38 analogues as dimethylformamide swollen gels gave very similar structures. Secondary structure prediction and model-building of ordered arrays, compatible with our results, suggest that beta A(34-42) forms a beta-hairpin structure, with the reverse turn at Val36-Gly37-Gly38-Val39 both in solution and on the resin during synthesis.

Amides↗