Resilience and GRIT among undergraduate nursing students during the COVID 19 pandemic

Objectives

Grit and resilience are related but separate concepts. Grit is a long-term commitment toward goals, and it impacts student success and academic achievement. Resilience is the ability of students to recover from stress. Both are important factors in nursing students.

Methods

This descriptive study included surveys measuring demographics, grit, and resilience among two cohorts of senior nursing students in their last semester and explored challenges and difficulties experienced during the COVID-19 pandemic.

Results

The mean grit score for all students was 4.0 (0.52) and the mean resilience score was 3.63 (0.73). Directed content analysis of the ten open-ended survey questions revealed three themes: Impact on Education, Personal Impact, and Coping Mechanisms.

Conclusions

Grit and resilience are important factors that can contribute to success in nursing programs and as graduate nurses in the healthcare settings.

Assessing the Impact of Unfolding Case Study Scenarios during High-Fidelity Pediatric Simulation among Undergraduate Nursing Students

Simulation helps to prepare prelicensure nursing students for practice by providing opportunities to perform clinical skills and make decisions in a safe environment. The integration of nursing knowledge, skills, and decision-making abilities during simulated unfolding case-study scenarios may enhance student self-confidence and foster clinical judgement skills. The purpose of this study was to assess the impact of simulation using unfolding case-study scenarios on undergraduate nursing students’ self-confidence in pediatric nursing knowledge, skills, and clinical judgment/decision-making abilities. This mixed methods study included a pre- and post-survey design to evaluate undergraduate nursing students’ confidence in pediatric nursing knowledge, skills, and decision-making abilities after participation in both an instructor-led (guided) and a student-led (decision-making) simulation involving unfolding case-study scenarios. Friedman’s ANOVA analyses revealed that all 16-items demonstrated statistically significant differences between the three measured responses (pre-simulation and both post-simulation surveys). Post-hoc Wilcoxon signed-rank tests revealed statistically significant differences in student ratings pre-simulation and post-instructor-led (guided) experience for all 16-scored items. The qualitative themes identified were perception of experience, pediatric nursing care, assimilation of knowledge, and critical thinking. Unfolding case-study simulation experiences positively impact the learning, self-confidence, and clinical judgement of undergraduate nursing students.

The impact of telehealth objective structured clinical evaluations in intraprofessional nursing education: A mixed methods study

BACKGROUND

Telehealth is an expanding modality of providing care. In 2018, the National Organization of Nurse Practitioner Faculties (NONPF) released a white paper encouraging the inclusion of telehealth into nurse practitioner education. It is important for nursing students to gain experience with telehealth so that they are prepared to provide care via telehealth.

OBJECTIVES

The purpose of this project was to evaluate the impact of incorporating telehealth simulation into objective structured clinical examinations (OSCEs) in the family nurse practitioner (FNP) and bachelor of science in nursing (BSN) programs.

SETTING

This study was conducted at a public, liberal arts university in a rural area of the Southeast United States.

PARTICIPANTS

The FNP and BSN students participated in this study. The FNP program is a hybrid master's degree program, which has a two-year plan of study. The BSN program is a traditional campus-based program, which includes two years of upper-division nursing courses.

METHODS

This mixed-methods study included a pre- and post-survey design utilizing both quantitative and qualitative measures to evaluate undergraduate and graduate nursing students understanding of and comfort with telehealth and their perceptions of a simulated intradisciplinary telehealth OCSE experience.

RESULTS

Students' telehealth knowledge, skills, and confidence were improved after the telehealth OSCE experience. Directed content analysis of the responses revealed three themes: increased knowledge of telehealth, technical difficulties, and teamwork/communication.

CONCLUSIONS

It is beneficial for both undergraduate and family nurse practitioner students to have exposure to telehealth in their respective curriculums.

The Impact of Collaborative Testing in Graduate Nursing Education

BACKGROUND

Collaborative testing is an educational strategy that allows students to work in teams when completing an examination.

METHOD

Twenty-eight family nurse practitioner students took four course examinations individually and collaboratively. Five comprehensive questions were included on the fourth examination. A survey was administered at the end of the course, with permission.

RESULTS

All collaborative test scores were higher than the traditional test scores (traditional mean range = 80.78 [8.53] to 84.07 [7.41], collaborative mean range = 93.54 [3.77] to 94.07 [2.80], all p values < .001). Students did not demonstrate significant changes in mean scores for cumulative content on test four. Directed content analysis revealed four themes: Enhanced Understanding of Content, Collaboration With Classmates, Socialization, and Improved Grades.

CONCLUSION

In graduate nursing education, collaborative testing may be an effective strategy to improve teamwork and communication skills, enrich relationships, and enhance critical thinking. [J Nurs Educ. 2019;58(6):357-359.].

Exploring the experiences of novice clinical instructors in physical therapy clinical education: a phenomenological study

OBJECTIVE

To explore the perceptions of novice physical therapy clinical instructors (CIs) about their interactions and teaching behaviours with physical therapy students.

DESIGN

A phenomenological approach using semi-structured interviews and a focus group.

PARTICIPANTS

Six novice physical therapy CIs (less than two years as a CI and supervised fewer than three students) were recruited purposefully from a large metropolitan area in the USA. All participants were credentialed by the American Physical Therapy Association as CIs.

MAIN OUTCOME MEASURES

Transcripts of interview data and focus group data were analysed using interpretative analysis for themes and subthemes.

RESULTS

Participants viewed the transition of students from the classroom to the clinic as their primary role, using strategies of 'providing a way in', 'fostering critical thinking', 'finding a balance', 'overcoming barriers' and 'letting go'.

CONCLUSION

While novice CIs showed skill in fostering student reflection and providing orientation, they struggled with student autonomy and balancing the competing obligations of patient care and clinical instruction. They expressed issues related to anxiety and lack of confidence. In the future, novice CIs could benefit from training and support in these areas.

Abstract PD09-04: Weight Loss in Postmenopausal Women Is Associated with Modulation of Serum and Tissue Based Risk Biomarkers

Background

In a pilot study, a structured program of reduced energy diet, physical activity, and weekly group behavioral intervention with other high risk women was successful at producing a median 11% weight loss with at least a 5% weight loss in 88% of subjects. We evaluated the association of weight loss with changes in serum and breast tissue risk and mechanisms of action biomarkers. Methods

High risk postmenopausal women with BMI &gt;25 kg/m2 had breast tissue harvested by random periareolar fine needle aspiration (RPFNA) before and after a 6-month energy balance intervention. Specimens were evaluated for biomarkers including cytomorphology, proliferation (immunocytochemical Ki-67), gene expression by RT-qPCR, and expression of cytokines and adpokines by Luminex assay. Fasting serum was assayed for insulin, glucose, adiponectin, leptin, high sensitivity CRP, IL-6, prolactin, SHBG, estradiol and testosterone using ELISA or Luminex.

Results

For 24 biomarker evaluable subjects, 21 had &gt;5% weight loss (median = 11%). Cytologic atypia was present in 10/24 at baseline and 4/24 at 6 months (p=0.034). For 20 subjects with sufficient cells for assessment of Ki-67 at both times, median baseline Ki-67 was 0.7% and off study 0.3%, with a median change of -0.2% (p=0.19). Statistically significant changes (≥0.003; Wilcoxon) were observed for serum levels of adiponectin, adiponectin:leptin ratio, and SHBG (increases); and leptin, bioavailable estradiol and hsCRP (decreases). Reduction was also observed for insulin (p=0.018) and bioavailable testosterone (p=0.033). These results were duplicated (p≥0.014) by Luminex for adiponectin, leptin, adiponectin: leptin ratio, and insulin; plus hepatocyte growth factor (HGF, decrease). Also, an increase in the adiponectin:leptin ratio was observed for the RPFNA specimens (p=0.012). Gene expression (RT-qPCR) of pS2 was significantly modified (decrease, p=0.035). Further, the weight loss (expressed as relative change) was highly statistically correlated with change (relative) in serum leptin, adiponectin:leptin ratio, SHGB, and free estradiol; as well as with relative change in adiponectin:leptin ratio in RPFNA specimens. Conclusion

Weight loss in high risk postmenopausal women is accompanied by significant modulation of numerous serum and breast tissue-based biomarkers. For several risk and response biomarkers there is a significant correlation between change in the biomarker and the weight loss achieved. This suggests the possibility of identifying mechanisms of action and signaling pathways for dietary/energy balance interventions that may reduce risk for development of breast cancer.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD09-04.

Toxicity of chlorpyrifos adsorbed on humic colloids to larval walleye (Stizostedion vitreum)

After application, organophosphorus insecticides (OPs) are often strongly adsorbed to soil constituents. Because of their relatively low water solubility, OPs may be transferred from field to stream adsorbed on suspended solids. However, we are not aware of research done to evaluate the bioavailability (i.e., toxicity) of OPs transported on suspended solids to fish. We conducted 48-h static toxicity tests to determine the toxicity of chlorpyrifos in aqueous solution and adsorbed on calcium-saturated humic acid (HA) to three larval stages of walleye (Stizostedion vitreum). Three concentrations of chlorpyrifos adsorbed on HA, a HA control, and a chlorpyrifos-only treatment were tested. Fish that survived the 48-h static toxicity tests were analyzed to determine total cholinesterase (ChE) activity. In general, survival of all larval stages of walleye exposed to chlorpyrifos-HA complexes was less than that of walleye exposed to HA controls and the chlorpyrifos-only treatment, which were not toxic to walleye. Cholinesterase inhibition of larval walleye exposed to chlorpyrifos-HA complexes was similar to the ChE inhibition observed in larval walleye exposed to chlorpyrifos in the aqueous phase. These laboratory experiments indicate potential toxicity of chlorpyrifos-soil complexes to larval fish.

Environmental, biological, and methodological factors affecting cholinesterase activity in walleye (Stizostedion vitreum)

Organophosphorus (OP) insecticides have high acute toxicity toward many nontarget vertebrate and invertebrate organisms, but direct measurement of OPs in environmental samples is difficult because their concentrations may fall below detection limits within hours to days after entering aquatic ecosystems. Because OPs exert toxicity through cholinesterase (ChE) inhibition, which may persist for up to several weeks, ChE inhibition has been widely used in aquatic ecosystems as a biomarker for OP exposure in aquatic organisms. However, the biological, environmental, and methodological factors affecting ChE activity have not been well documented and must be considered and understood before ChE activity can be used as a dependable indicator of OP exposure to aquatic organisms. This study examined the influence of water temperature, size of larval and juvenile walleye (Stizostedion vitreum), stress, long-term storage, postmortem changes, and methods of euthanasia on ChE activity. Water temperature (17.2, 20.9, and 24.6 degrees C), stress, long-term storage (up to 180 days), postmortem changes, and method of euthanasia had no effect on ChE activity of walleye. There was a strong positive correlation (r = 0.87) between whole body ChE activity and total length (7.2-17.9 mm) for larval walleye, but a negative correlation between brain ChE activity and total length (59-164 mm) for juvenile walleye (r = 0.75). Because size, age, and development may affect ChE activity, fish of similar size should be used when evaluating the effects of ChE inhibitors. If fish of similar size are not available, it is recommended that relations between size, age, and development be understood so estimates of variation in ChE activity can be made.

B7 family molecules: novel immunomodulators at the maternal-fetal interface

The placenta utilizes both active and passive mechanisms to evade rejection by the maternal immune system. Recently, the mRNA for two newly cloned members of the B7 family of immunomodulatory cell-associated proteins have been identified in the human term placenta. In this article, we review the current knowledge of the B7 family member B7-H1, and discuss how it may participate in modulation of the maternal immune system at the maternal-fetal interface. B7-H1 has been found to possess immunostimulatory or immunoinhibitory properties, and immunohistological examination of first trimester and term placenta has revealed that this protein is abundant in the placenta. B7-H1 is highly expressed by both the syncytiotrophoblast and extravillous cytotrophoblast, both of which lie in direct contact with maternal blood and tissue. Further, treatment of the choriocarcinoma cell line, JEG-3, with recombinant human interferon (IFN)-gamma resulted in a dose-dependent increase in the abundance of the message for B7-H1, suggesting that IFN-gamma could regulate expression of B7-H1 by the trophoblast. These studies document that the positioning of B7-H1 at the maternal-fetal interface is such that it could participate in suppression of activated maternal leukocytes.

Death-inducing tumour necrosis factor (TNF) superfamily ligands and receptors are transcribed in human placentae, cytotrophoblasts, placental macrophages and placental cell lines

Human placentae and two of the cell types in placentae (cytotrophoblasts and macrophages) were examined by RT-PCR for transcripts of the eight TNF superfamily ligands known to induce death of activated immune cells, tumour cells, and virus-infected cells (TNFalpha, LT alpha, LT beta, FasL, TRAIL, TWEAK, LIGHT, 4-1BBL). Transcripts for all ligands were detected in term placenta but LT alpha and 4-1BBL were not detected in first trimester placenta. Although term cytotrophoblasts contained mRNAs specific for TNF alpha, LT alpha, TWEAK, and 4-1BBL, messages encoding LT beta, FasL, TRAIL, and LIGHT were absent. In term placental macrophages, messages for all ligands except 4-1BBL were present. Transcripts for the 14 receptors to which the ligands bind, six of which contain death-domains (TNFR1, Fas, DR3, DR4, DR5, DR6), were also identified using RT-PCR. Term and first trimester placentae contained transcripts for all receptors except 4-1BB. Although term cytotrophoblasts lacked receptor mRNA encoding 4-1BB and OPG, term placental macrophages lacked DcR1 and OPG. Detection of nearly all the death-inducing TNF superfamily ligands and their receptors in human placentae implies that these powerful cytokines contribute to programmed or activated cell death in this organ.

TRAIL (Apo-2L) and TRAIL receptors in human placentas: implications for immune privilege

Mechanisms accounting for protection of the fetal semiallograft from maternal immune cells remain incompletely understood. In other contexts, interactions between TRAIL (TNF-related apoptosis-inducing ligand/Apo-2L) and its receptors kill activated lymphocytes. The purpose of this study was therefore to investigate the potential of the TRAIL/TRAIL-R system to protect the placenta against immune cell attack. Analysis by Northern blotting demonstrated mRNAs encoding TRAIL as well as the four TRAIL receptors (DR4, DR5, DcR1/TRID, DcR2/TRUNDD) in human placentas. Immunohistochemical experiments demonstrated that TRAIL protein is prominent in syncytiotrophoblast, an uninterrupted placental cell layer that is continuously exposed to maternal blood, as well as in macrophage-like placental mesenchymal cells (Hofbauer cells). Studies on cell lines representing trophoblasts (Jar, JEG-3 cells) and macrophages (U937, THP-1 cells) showed that both lineages contained TRAIL mRNA and that steady state levels of transcripts were increased 2- to 11-fold by IFN-gamma. By contrast, cell lineage-specific differences were observed in expression of the TRAIL-R genes. Although all four lines contained mRNA encoding the apoptosis-inducing DR5 receptor, only trophoblast cells contained mRNA encoding the DcR1 decoy receptor and only macrophages contained DcR2 decoy receptor transcripts. DR4 mRNA was present only in THP-1 cells and was the only TRAIL-R transcript increased by IFN-gamma. Cytotoxicity assays revealed that the two trophoblast cell lines were resistant, whereas the two macrophage lines were partially susceptible to killing by rTRAIL. Collectively, the results are consistent with a role for the TRAIL/TRAIL-R system in the establishment of placental immune privilege.

Trophoblastic cell lines generated from tumour necrosis factor receptor-deficient mice reveal specific functions for the two tumour necrosis factor receptors

In mice and humans, expression of the tumour necrosis factor receptor-1 (TNF-R1) gene in placental trophoblast cells is constitutive whereas expression of the TNF-R2 gene is developmentally programmed. In order to study the individual functions of TNF-R1 and -R2 in this lineage, cell lines were generated from placental explants of homozygous matings of gestation day 10 outbred mice (Swiss-Webster), TNF-R1-deficient (TNF-R1-/-) and TNF-R2-/- transgenic mice as well as the background strain for the TNF-R2-/- mice (WT, C57BL/6x129). All of the cells exhibited trophoblast markers; they contained cytokeratin intermediate filaments, expressed alkaline phosphatase activity and displayed transferrin receptors, but were negative for vimentin filaments and the macrophage marker, F4/80. Analysis of DNA by polymerase chain reaction demonstrated the expected TNF-R genotype in each line. In experiments testing the effects of recombinant mouse TNF-alpha (rmTNF-alpha) on viability and proliferation of the cell lines, rmTNF-alpha modestly but dose-dependently inhibited the growth of WT and TNF-R2-/- cells while having no effect on TNF-R1-/- cells. Actinomycin D-treated WT and, to a lesser extent, TNF-R2-/- cells, were more sensitive to growth inhibition than untreated cells whereas TNF-R1-/- cell responses remained unchanged. These data indicated that rmTNF-alpha inhibits growth of trophoblastic cells through TNF-R1 and that newly synthesized protein(s) provide partial protection against toxicity. In contrast to the receptor species-specific effects on cell growth exerted by rmTNF-alpha, both TNF-R mediated inhibition of alkaline phosphatase activity. Collectively, the observations support the postulate that receptor expression is the key factor which determines the nature and extent of TNF-alpha effects on trophoblast cell growth and function.

The mouse macrophage activation-associated marker protein, p71/73, is an inducible prostaglandin endoperoxide synthase (cyclooxygenase)

The inducible protein p71/73 marks the response of mouse macrophages to one of several stimuli (e.g., bacterial lipopolysaccharide or poly I:C) that trigger the expression of cytolytic activity when these cells have previously been primed for tumor cell killing by interferon-gamma (IFN-gamma). The results reported here identify this marker protein as the inducible prostaglandin endoperoxide synthase (PES), TIS10/PES-2. Identification was based on four findings: (1) p71/73, like the TIS10/PES-2 protein, was associated with cellular membranes; (2) the sequence of amino acids in the NH2 terminus of both p71 and p73 was 96% identical to the predicted NH2-terminal sequence of the TIS10/PES-2 protein; (3) a polyclonal antiserum raised against the COOH-terminal region of the TIS10/PES-2 gene product recognized p71/73 in immunoblots; and (4) dexamethasone, which blocks induction of TIS10/PES-2 expression, inhibited the induction of both p71/73 synthesis and tumoricidal activity in macrophage. Several regulatory roles for this protein in the activation process are possible.

Activation-associated marker proteins: peptide mapping and their expression in macrophage cell lines

The activation-associated markers, p47b and p71/73, have been recognized as minor proteins in peritoneal and bone marrow culture-derived macrophages activated for tumor cell killing. Proteins with identical characteristics of migration on 2-dimensional gels and comparable Cleveland peptide maps are described here in macrophage cell lines that could be activated for tumor cell killing (J774A.1, RAW 264, UNC-2). Macrophage cell lines that could not be activated (P388D1 and PU5-1.8) did not express the markers. The expression of these markers in activatable macrophage cell lines strengthens their association with the activation process and provides a bulk source of the proteins for purification studies.

Loss of 4.5S RNA induces the heat shock response and lambda prophage in Escherichia coli

During depletion of 4.5S RNA, cells of Escherichia coli displayed a heat shock response that was simultaneous with the first detectable effect on ribosome function and before major effects on cell growth. Either 4.5S RNA is involved directly in regulating the heat shock response, or this particular impairment of protein synthesis uniquely induces the heat shock response. Several hours later, lambda prophage was induced and the cells lysed.

Levels of DNA topoisomerases, single-stranded-DNA-binding protein, and DNA polymerase I in rho+ and rho-15 strains of Escherichia coli

The Escherichia coli rho-15 mutant, which is highly defective in transcription termination, was examined to see whether its reduced DNA superhelicity could be explained by altered expression of proteins that may affect DNA structure. Levels of DNA gyrase and topoisomerase I were normal; levels of single-stranded-DNA-binding protein, DNA polymerase I, and a protein tentatively identified as Lon were significantly altered.

Genomically linked cellular protein databases derived from two-dimensional polyacrylamide gel electrophoresis

In its most useful form a cellular protein database should be genomically based, because it is the genome which determines both the total number of proteins a cell can make and the particular ones that will be made under any given condition. Such a database should trace each protein back to its structural gene, and should account for every structural gene of a cell. Recent advances in molecular biology greatly facilitate the construction of such gene-protein databases. The mapping of genes of unidentified proteins resolved from total cell extracts on two-dimensional gels can now be accomplished by largely biochemical methods, without the necessity of isolating mutants or performing genetic crosses. Other techniques permit one to search gels for the product of any newly discovered gene (or open reading frame) suspected of encoding a protein. Consequently, gene-protein indices can be built independently and simultaneously from either direction--deducing the genetic map from the protein pattern, or finding the protein pattern from information encoded in the genome. A database of this sort is being constructed for the bacterium, Escherichia coli. Given the current pace of DNA nucleotide sequencing, the development of total gene-protein indices for a variety of cells can be anticipated in the near future.

lon gene product of Escherichia coli is a heat-shock protein

The product of the pleiotropic gene lon is a protein with protease activity and has been tentatively identified as protein H94.0 on the reference two-dimensional gel of Escherichia coli proteins. Purified Lon protease migrated with the prominent cellular protein H94.0 in E. coli K-12 strains. Peptide map patterns of Lon protease and H94.0 were identical. A mutant form of the protease had altered mobility during gel electrophoresis. An E. coli B/r strain that is known to be defective in Lon function contained no detectable H94.0 protein under normal growth conditions. Upon a shift to 42 degrees C, however, the Lon protease was induced to high levels in K-12 strains and a small amount of protein became detectable at the H94.0 location in strain B/r. Heat induction of Lon protease was dependent on the normal allele of the regulatory gene, htpR, establishing lon as a member of the high-temperature-production regulon of E. coli.

Gene-protein index of Escherichia coli K-12

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High-pressure liquid chromatographic determination of chlorothiazide and hydrochlorothiazide in plasma and urine: preliminary results of clinical studies

High-pressure liquid chromatographic procedures were developed for the determination of chlorothiazide and hydrochlorothiazide in plasma and urine. The plasma assay incorporates a preextraction procedure that eliminates interference by endogenous substances. Chromatography is carried out on an octadecyl reversed-phase column. Mobile phases are 15% methanol in 0.01 M acetic acid for plasma and 4% acetonitrile in 0.01 M sodium perchlorate, adjusted to pH 4.6, for urine. At a flow rate of 2.5 ml/min, the retention times for chlorothiazide and hydrochlorothiazide are 3.5 and 4.6 min for plasma and 10.5 and 13.5 min for urine, respectively. Preliminary results of a clinical study in fasting male volunteers showed that the plasma levels and urinary excretion rate of chlorothiazide peaked at 1-2 hr following a 500-mg oral dose and subsequently declined irregularly. On the other hand, the plasma levels and urinary excretion rate of hydrochlorothiazide peaked at 2-3 hr following a 50-mg oral dose and subsequently declined in biphasic fashion. Urinary excretion rates of both chlorothiazide and hydrochlorothiazide closely resemble their concentration profiles in plasma.

Normal and dystrophic embryonic chicken pectoralis muscle cultures: I. Cell differentiation, protein synthesis, and enzyme levels

Normal (line 200) and dystrophic (line 307) embryonic chicken pectoralis muscle cells were studied in cell culture over a period of 2 weeks. During the first 4 days, normal and dystrophic cultures exhibited similar developmental increases in the number of nuclei within multinucleated myotubes, however, dystrophic muscle cells degenerated approximately twice as fast as normal cells once the initial burst of myoblast fusion was complete. The apparent synthesis rate of nonmyofibrillar proteins was similar in normal aand dystrophic cells throughout development, but the apparent synthesis rates of myosin heavy chain and the myofibrillar protein fraction were 50%--90% higher in dystrophic muscle cultures once maturity had been reached (days 6--14). The specific activities of creatine kinase and phosphofructokinase were not affected by the dystrophic condition; however, specific activity of AMP-deaminase was depressed 25%--40% in the dystrophic muscle cultures.

Identity of the B56.5 protein, the A-protein, and the groE gene product of Escherichia coli

Protein B56.5 is a major Escherichia coli protein, originally identified on two-dimensional gels as an abundant cellular protein with unique regulation. The groE gene product is a bacterial protein essential for the assembly of many diverse bacteriophages. The ribosomal A-protein is a large, acidic protein of unknown function associated with isolated, washed ribosomes. On the basis of comigration in two-dimensional gels, oligopeptide map patterns, amino acid composition, immunological specificity, physical properties, and genetic analysis, protein B56.5 has now been shown to be the groE gene product and to be identical with the A-protein.

Pharmacokinetics of oral and intravenous fluorouracil in humans

The pharmacokinetics of fluorouracil were examined after single 250-mg iv doses and 500-mg oral doses to female patients with breast cancer. In five patients who received intravenous fluorouracil, the mean peak plasma level of unchanged drug was 13.4 microgram/ml, the elimination half-life was 6.3 min, and the plasma clearance was 1410 ml/min. The last value is similar to the hepatic blood flow. In six patients who received oral fluorouracil, the mean peak value of unchanged drug in plasma, which occurred within 20 min of dosing, was 8.3 microgram/ml, and the fluorouracil elimination half-life was 7.2 min. The overall bioavailability of oral fluorouracil as unchanged drug was 28%, and the variation in plasma drug levels between individuals was similar following oral and intravenous doses. The data provide additional evidence of saturable hepatic metabolism of fluorouracil during the first pass.

Protein identifications on O'Farrell two-dimensional gels: locations of 55 additional Escherichia coli proteins

The resolution of proteins from whole-cell homogenates by two-dimensional gel electrophoresis is sufficiently reproducible and precise to permit different laboratories to exchange information about them. To the previous total of 81 we add the locations of 55 Escherichia coli proteins determined with the aid of purified proteins and mutant strains supplied by many investigators. The criteria used to establish the identifications of protein spots include migration with marker proteins, altered position or amount in appropriate mutant or plasmid-carrying strains, physiological behavior, and peptide map pattern.

Protein identifications of O'Farrell two-dimensional gels: locations of 81 Escherichia coli proteins

The two-dimensional gel electrophoresis method of P. H. O'Farrell readily resolves approximately 1,000 proteins from whole-cell homogenates. We have found that the location of most individual proteins is sufficiently reproducible and precise to permit different laboratories to exchange information about them. We present the location of 81 Escherichia coli structural proteins, binding proteins, enzymes, and factors, identified with the aid of purified proteins supplied to us by many investigators.