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Biomedical subjects

T Richmond

Publications and source records attributed to T Richmond.

16 recordsLinked to original sources
PubMed2006

Microdissection-based high-resolution genomic array analysis of two patients with cytogenetically identical interstitial deletions of chromosome 1q but distinct clinical phenotypes.

We describe two boys with cytogenetically identical interstitial deletions in the q42.11-q42.13 region of the long arm of chromosome 1 detected by high-resolution G-banding analysis. These children share some phenotypic features but also exhibit distinct morphologic differences. We further characterized the deletions using a new technical strategy--microdissection-based high-resolution genomic array (MHGA) analysis--to define the breakpoints, genomic sizes, and gene contents of the deletions. This showed that the patients had distinguishable deletions that were adjacent but did not overlap, thus explaining the observed phenotypic differences. These results were surprising because we expected at least some degree of overlap to explain the features that were shared. MHGA can quickly give precise and detailed information about any rearrangement in the genome using as little material as a single cell. This novel strategy provides unique advantages for both clinical diagnosis and genomic research.

Child, Preschool↗
PubMed2001

Modifications of cellulose synthase confer resistance to isoxaben and thiazolidinone herbicides in Arabidopsis Ixr1 mutants.

In many higher plants, cellulose synthesis is inhibited by isoxaben and thiazolidinone herbicides such as 5-tert-butyl-carbamoyloxy-3-(3-trifluromethyl) phenyl-4-thiazolidinone. Semidominant mutations at the IXR1 and IXR2 loci of Arabidopsis confer isoxaben and thiazolidinone resistance. Isolation of the IXR1 gene by map-based cloning revealed that it encodes the AtCESA3 isoform of cellulose synthase. The two known mutant alleles contain point mutations that replace glycine 998 with aspartic acid, and threonine 942 with isoleucine, respectively. The mutations occur in a highly conserved region of the enzyme near the carboxyl terminus that is well separated from the proposed active site. Although the IXR1 gene is expressed in the same cells as the structurally related RSW1 (AtCESA1) cellulose synthase gene, these two CESA genes are not functionally redundant.

Alleles↗
PubMed2000

Higher plant cellulose synthases.

SUMMARY: Cellulose, an aggregate of unbranched polymers of beta-1,4-linked glucose residues, is the major component of wood and thus paper, and is synthesized by plants, most algae, some bacteria and fungi, and even some animals. The genes that synthesize cellulose in higher plants differ greatly from the well-characterized genes found in Acetobacter and Agrobacterium sp. More correctly designated as 'cellulose synthase catalytic subunits', plant cellulose synthase (CesA) proteins are integral membrane proteins, approximately 1,000 amino acids in length. The sequences for more than 20 full-length CesA genes are available, and they show high similarity to one another across the entire length of the encoded protein, except for two small regions of variability. There are a number of highly conserved residues, including several motifs shown to be necessary for processive glycosyltransferase activity. No crystal structure is known for cellulose synthase proteins, and the exact enzymatic mechanism is unknown. There are a number of mutations in cellulose synthase genes in the model organism Arabidopsis thaliana. Some of these mutants show altered morphology due to the lack of a properly developed primary or secondary cell wall. Others show resistance to well-characterized cellulose biosynthesis inhibitors.

Arabidopsis↗
PubMed2000

Coordinated plant defense responses in Arabidopsis revealed by microarray analysis.

Disease resistance is associated with a plant defense response that involves an integrated set of signal transduction pathways. Changes in the expression patterns of 2,375 selected genes were examined simultaneously by cDNA microarray analysis in Arabidopsis thaliana after inoculation with an incompatible fungal pathogen Alternaria brassicicola or treatment with the defense-related signaling molecules salicylic acid (SA), methyl jasmonate (MJ), or ethylene. Substantial changes (up- and down-regulation) in the steady-state abundance of 705 mRNAs were observed in response to one or more of the treatments, including known and putative defense-related genes and 106 genes with no previously described function or homology. In leaf tissue inoculated with A. brassicicola, the abundance of 168 mRNAs was increased more than 2.5-fold, whereas that of 39 mRNAs was reduced. Similarly, the abundance of 192, 221, and 55 mRNAs was highly (>2.5-fold) increased after treatment with SA, MJ, and ethylene, respectively. Data analysis revealed a surprising level of coordinated defense responses, including 169 mRNAs regulated by multiple treatments/defense pathways. The largest number of genes coinduced (one of four induced genes) and corepressed was found after treatments with SA and MJ. In addition, 50% of the genes induced by ethylene treatment were also induced by MJ treatment. These results indicated the existence of a substantial network of regulatory interactions and coordination occurring during plant defense among the different defense signaling pathways, notably between the salicylate and jasmonate pathways that were previously thought to act in an antagonistic fashion.

Arabidopsis↗
PubMed2000

Chasing the dream: plant EST microarrays.

DNA microarray technology is poised to make an important contribution to the field of plant biology. Stimulated by recent funding programs, expressed sequence tag sequencing and microarray production either has begun or is being contemplated for most economically important plant species. Although the DNA microarray technology is still being refined, the basic methods are well established. The real challenges lie in data analysis and data management. To fully realize the value of this technology, centralized databases that are capable of storing microarray expression data and managing information from a variety of sources will be needed. These information resources are under development and will help usher in a new era in plant functional genomics.

Chromosome Mapping↗
PubMed1994

A Delphi study on research priorities for trauma nursing.

OBJECTIVES: To identify and prioritize research questions of importance to trauma patient care and of interest to trauma nurses. METHOD: A three-round Delphi technique was used to solicit, identify, and prioritize problems for trauma nursing research. In round 1, experienced trauma nurses (N = 208) generated 513 problems, which were analyzed, categorized, and collapsed into 111 items for subsequent rounds. Round 2 participants rated each research question on a 1 to 7 scale on two criteria: impact on patient welfare and value for practicing nurses. Group median scores provided by 166 round 2 respondents and respondents' individual round 2 scores were indicated on the round 3 questionnaire. Subjects rated the questions again on the same criteria and indicated whether nurses, independently or in collaboration with other health professionals, should assume responsibility for that research. Median and mean scores and rank order were determined for each item. RESULTS: Respondents who completed all three rounds (n = 137) had a mean of 8.3 years of trauma experience. Nine research questions ranked within the top 20 on both criteria. The two research questions that ranked highest on both criteria were: What are the most effective nursing interventions in the prevention of pulmonary and circulatory complications in trauma patients? and What are the most effective methods for preventing aspiration in trauma patients during the postoperative phase? The third-ranked question regarding patient welfare was: What psychological and lifestyle changes result from traumatic injury? Regarding value for practicing nurses, What are the most effective educational methods to prepare and maintain proficiency in trauma care providers? ranked third. CONCLUSION: These research priorities provide impetus and direction for nursing and collaborative investigation in trauma care.

Adult↗
PubMed1994

Critical care nurse practitioners: evolution of the advanced practice nursing role.

This literature review was done to explore the use of master's-prepared nurse practitioners to manage critically ill patients. Data-based, anecdotal, clinical, analytic, and position papers published over the past 10 years in the medical and nursing literature were reviewed. This article synthesizes findings on the use of nurse practitioners in clinical settings including primary and specialty care settings, describes favorable outcomes of advanced practice nurses, and identifies factors that must be addressed as these roles increase in use in critical care settings. Nurse practitioners' movement into critical care settings should be undertaken. Additional federal support to ensure the preparation of these practitioners in adequate numbers is needed. Attention to issues of direct reimbursement, salaries, impact of changing role boundaries, malpractice coverage, and prescription privileges must be addressed. Research programs to examine the effect of nurse practitioners in specialized care should continue.

Critical Care↗
PubMed1993

Tertiary nurse practitioners.

Tertiary nurse practitioners are proposed to meet the specialized health care needs of complex patients. Societal changes, increasing numbers of medically vulnerable people and increased costs of health care demand innovative responses to health care delivery. Nurse practitioners' effectiveness in primary care settings supports their introduction into acute care settings. Nurse practitioners are involved in tertiary care in response to a need for the delivery of care to patients with specialized needs. The evolution of the tertiary nurse practitioner role pre-dated the response of educational institutions to provide appropriate preparation for practitioners in tertiary care. Curricular imperatives and policy issues that will influence professional practice of the tertiary nurse practitioner are discussed.

Curriculum↗
PubMed1977

Solvents, interfaces and protein structure.

Mean packing densities in protein interiors are comparable to those of most organic solids but the variations between small regions may be substantial. Packing defects may be related to allowed structural fluctuations. Molecular surface areas can be correlated with free energies of transfer between different solvents. The proportionality factor will depend, in general, on the nature of the solute and both the solvents. The changes in solvent-protein interfacial area on chain folding are large and the implied changes in free energy from this solvent-squeezing effect are correspondingly large. The strong tendency to minimize surface area is reflected in the globular shape of most protein molecules or domains in larger structures. The formation of isolated units of secondary structure from an extended chain represents about one half of the eventual total area change. The tendencies of amino acids to form beta-sheets correlate well with the rank-ordered list based on non-polar area change for each residue type. The calculated area changes for helix and sheet formation are not identical in rank order. The rank-ordered list for alpha-helix formation correlates satisfactorily with the probability list prepared from actual structures if glutamic acid and tyrosine are removed. What special characteristics unrelated to surface area these two amino acids might have is not clear. Tertiary structure formation from preformed secondary structural units can be rank ordered on area change and possible nucleation sites can be identified. A prediction scheme for helix-helix interactions is proposed. The hydrophobic force begins to be felt when two helices are about 0.6 nm (6 A) from their final contact positions. Interfacial surface tension is a logical parameter to relate free energy and solvent contact area, but this macroscopic parameter must be used with great caution. It is suggested that water in the deep grooves, characteristic of the active sites of many enzymes, may have a substantially higher fugacity than bulk water as indicated, at least qualitatively, by the Kelvin equation based on surface curvature. Such water would be more easily displaced than its plane surface counterpart and could contribute significantly to ligand-binding energy. This factor would be in addition to the usual solvent entropic effects associated with surface area reduction on association.

Amino Acids↗
PubMedDate not supplied

A reflection on values in turbulent times.

We discuss how organizations, as cultures, react to times of turbulence, stress, and the importance of their foundational values during those times. By adapting the framework pioneered by the organizational analyst Manfred Kets de Vries, we use psychodynamic concepts to discuss a descriptive typology of behavior in which persons and organizations engage under stress. We also discuss the hazards inherent in losing sight of common core values, the dangers in the disconnects between stated values and behaviors, and how those disconnects can be destructive to organizations and to persons. We conclude with a plan that involves achieving insight, trust, and open communication on which members of organizations can base discussion and find common ground in articulating common core values. Throughout the article, we make applications to nursing organizations to focus attention on the currency of this topic for the profession.

Aggression↗