A mixed-methods evaluation of the impact of a pharmacist-led feedback pilot intervention on insulin prescribing in a hospital setting

AIMS

To explore the impact of a prescribing feedback intervention on insulin prescribing.

METHODS

This was a mixed-methods study in a hospital setting. An insulin prescribing feedback intervention was delivered verbally and in writing to twelve doctors. Insulin prescribing error frequency was compared to ten doctors who had not received the feedback intervention. Insulin prescribing was audited over four weeks at the start and end of the intervention period. Semi-structured interviews were conducted with participating doctors who had received feedback, and qualitative data analysed thematically to explore the impact of the intervention on their prescribing practice.

RESULTS

Prescribing data were collected on 370 insulin prescriptions with 241 errors identified. A significant reduction (χ2 = 22.6, p=<0.05) in insulin prescribing error frequency was observed in the intervention group, with a non-significant increase reported in the control group. Feedback was received positively and considered valuable by doctors, supporting development of their knowledge and skills and encouraging reflection on their prescribing performance. Doctors described enhanced confidence in insulin prescribing and a desire to improve as a prescriber and avoid harm, with feedback raising awareness of their development needs. Prescribers also described enhanced team work, with greater information and feedback seeking behavior to inform future prescribing decisions.

CONCLUSIONS

Feedback has potential to improve insulin prescribing and is a valued and acceptable process intervention for doctors. The impact on insulin prescribing practice is varied and complex influencing the capability, opportunity and motivation of prescribers to adapt and evolve their behavior in response to ongoing feedback.

Complete Transcriptome RNA-Seq

RNA-Seq is the leading technology for analyzing gene expression on a global scale across a broad spectrum of sample types. However, due to chemical modifications by fixation or degradation due to collection methods, samples often contain an abundance of RNA that is no longer intact, and the capability of current RNA-Seq protocols to accurately quantify such samples is often limited. We have developed an RNA-Seq protocol to address these key issues as well as quantify gene expression from the whole transcriptome. Furthermore, for compatibility with improved sequencing platforms, we use restructured adapter sequences to generate libraries for Illumina HiSeq, MiSeq, and NextSeq platforms. Our protocol utilizes duplex-specific nuclease (DSN) to remove abundant ribosomal RNA sequences while retaining other types of RNA for superior transcriptome profiling from low quantity input. We employ the Illumina sequencing platform, but this method is described in sufficient detail to adapt to other platforms.

Differentiation of Lung Cancer, Empyema, and Abscess Through the Investigation of a Dry Cough

An acute dry cough results commonly from bronchitis or pneumonia. When a patient presents with signs of infection, respiratory crackles, and a positive chest radiograph, the diagnosis of pneumonia is more common. Antibiotic failure in a patient being treated for community-acquired pneumonia requires further investigation through chest computed tomography. If a lung mass is found on chest computed tomography, lung empyema, abscess, and cancer need to be included on the differential and managed aggressively.

This report describes a 55-year-old Caucasian male, with a history of obesity, recovered alcoholism, hypercholesterolemia, and hypertension, presenting with an acute dry cough in the primary care setting. The patient developed signs of infection and was found to have a lung mass on chest computed tomography. Treatment with piperacillin-tazobactam and chest tube placement did not resolve the mass, so treatment with thoracotomy and lobectomy was required. It was determined through surgical investigation that the patient, despite having no risk factors, developed a lung abscess.

Lung abscesses rarely form in healthy middle-aged individuals making it an unlikely cause of the patient's presenting symptom, dry cough. The patient cleared his infection with proper management and only suffered minor complications of mild pneumoperitoneum and pneumothorax during his hospitalization.

Policy Transfer Among Regional-Level Organizations: Insights from Source Water Protection in Ontario

Organizations at the local and regional scales often face the challenge of developing policy mechanisms rapidly and concurrently, whether in response to expanding mandates, newly identified threats, or changes in the political environment. In the Canadian Province of Ontario, rapid, concurrent policy development was considered desirable by 19 regional organizations tasked with developing policies for protection of drinking water sources under very tight and highly prescribed mandates. An explicit policy transfer approach was used by these organizations. Policy transfer refers to using knowledge of policies, programs, and institutions in one context in the development of policies, programs, and institutions in another. This paper assesses three online mechanisms developed to facilitate policy transfer for source water protection in Ontario. Insights are based on a survey of policy planners from the 19 regional organizations who used the three policy transfer tools, supplemented by an analysis of three policies created and transferred among the 19 regional source water protection organizations. Policy planners in the study indicated they had used policy transfer to develop source protection policies for their regions-a finding confirmed by analysis of the text of policies. While the online policy transfer tools clearly facilitated systematic policy transfer, participants still preferred informal, direct exchanges with their peers in other regions over the use of the internet-based policy transfer mechanisms created on their behalf.

The revised human liver cytochrome P450 "Pie": absolute protein quantification of CYP4F and CYP3A enzymes using targeted quantitative proteomics

The CYP4F subfamily of enzymes has been identified recently to be involved in the metabolism of endogenous compounds (arachidonic acid and leukotriene B4), nutrients (vitamins K1 and E), and xenobiotics (pafuramidine and fingolimod). CYP4F2 and CYP4F3B are reported to be expressed in the human liver. However, absolute concentrations of these enzymes in human liver microsomes (HLMs) and their interindividual variability have yet to be determined because of the lack of specific antibodies. Here, an liquid chromatography with tandem mass spectrometry (LC-MS/MS)-based targeted quantitative proteomic approach was employed to determine the absolute protein concentrations of CYP4F2 and CYP4F3B compared with CYP3A in two panels of HLMs (n = 31). As a result, the human hepatic cytochrome P450 (P450) "pie" has been revised to include the contribution of CYP4F enzymes, which amounts to 15% of the total hepatic cytochrome P450 enzymes. CYP4F3B displayed low interindividual variability (3.3-fold) in the HLM panels whereas CYP4F2 displayed large variability (21-fold). However, CYP4F2 variability decreased to 3.4-fold if the two donors with the lowest expression were excluded. In contrast, CYP3A exhibited 29-fold interindividual variability in the same HLM panels. The proposed marker reaction for CYP4F enzymes pafuramidine/DB289 M1 formation did not correlate with CYP4F protein content, suggesting alternate metabolic pathways for DB289 M1 formation in HLMs. In conclusion, CYP4F enzymes are highly expressed in the human liver and their physiologic and pharmacologic roles warrant further investigation.

Establishing a framework for the Ad/abaxial regulatory network of Arabidopsis: ascertaining targets of class III homeodomain leucine zipper and KANADI regulation

The broadly conserved Class III homeodomain leucine zipper (HD-ZIPIII) and KANADI transcription factors have opposing and transformational effects on polarity and growth in all tissues and stages of the plant's life. To obtain a comprehensive understanding of how these factors work, we have identified transcripts that change in response to induced HD-ZIPIII or KANADI function. Additional criteria used to identify high-confidence targets among this set were presence of an adjacent HD-ZIPIII binding site, expression enriched within a subdomain of the shoot apical meristem, mutant phenotype showing defect in polar leaf and/or meristem development, physical interaction between target gene product and HD-ZIPIII protein, opposite regulation by HD-ZIPIII and KANADI, and evolutionary conservation of the regulator-target relationship. We find that HD-ZIPIII and KANADI regulate tissue-specific transcription factors involved in subsidiary developmental decisions, nearly all major hormone pathways, and new actors (such as indeterminate domain4) in the ad/abaxial regulatory network. Multiple feedback loops regulating HD-ZIPIII and KANADI are identified, as are mechanisms through which HD-ZIPIII and KANADI oppose each other. This work lays the foundation needed to understand the components, structure, and workings of the ad/abaxial regulatory network directing basic plant growth and development.

Prevalence and associated factors of sexual problems after early-stage breast cancer treatment: results of a French exploratory survey

OBJECTIVE

The objective of this study was to assess the prevalence and associated factors of sexual activity, sexual problems or sexual satisfaction in French early-stage breast cancer survivors (BCS).

METHODS

Eight hundred and fifty eligible, post-treatment (6 months-5 years) female patients, aged 18-70 years, randomly selected from a consultation list, were invited to fill in questionnaires exploring quality of life (EORTC QLQ-C30 and QLQ-BR23), body image scale, and sexuality (Sexual Activity Questionnaire-SAQ; Relationship and Sexuality Scale; French Sexual Behaviour Survey-CSF).

RESULTS

Fifty-three percent of BCS agreed to participate. Participating women (n=378) were younger, more often premenopausal at diagnosis and with a more recent diagnosis than non-respondents. The prevalence of sexual problems was significantly higher in BCS compared with adjusted data from a French female representative sample (p<0.0001). In logistic regression, no sexual activity (R(2) =0.37) or sexual dissatisfaction (R(2) =0.28) were associated with the feeling of emotional separation in the couple or of partner's fear of sexual intercourse, lower emotional functioning, poorer body image, or co-morbidities. In sexually active women (71% of respondents), lower frequency of sexual activity (R(2) =0.26), lower sexual pleasure (R(2) =0.22), or higher sexual discomfort (R(2) =0.22) were associated with the feeling of emotional separation in the couple or of partner's fear of sexual intercourse, lower emotional functioning, age (>50 years), nausea, or insomnia (all Hosmer-Lemeshow tests: p=NS).

CONCLUSIONS

Psychological factors including the perception of the couple relationship appeared prominent in BCS women's experience of sexual problems.

Establishment of the vernalization-responsive, winter-annual habit in Arabidopsis requires a putative histone H3 methyl transferase

Winter-annual accessions of Arabidopsis thaliana are often characterized by a requirement for exposure to the cold of winter to initiate flowering in the spring. The block to flowering prior to cold exposure is due to high levels of the flowering repressor FLOWERING LOCUS C (FLC). Exposure to cold promotes flowering through a process known as vernalization that epigenetically represses FLC expression. Rapid-cycling accessions typically have low levels of FLC expression and therefore do not require vernalization. A screen for mutants in which a winter-annual Arabidopsis is converted to a rapid-cycling type has identified a putative histone H3 methyl transferase that is required for FLC expression. Lesions in this methyl transferase, EARLY FLOWERING IN SHORT DAYS (EFS), result in reduced levels of histone H3 Lys 4 trimethylation in FLC chromatin. EFS is also required for expression of other genes in the FLC clade, such as MADS AFFECTING FLOWERING2 and FLOWERING LOCUS M. The requirement for EFS to permit expression of several FLC clade genes accounts for the ability of efs lesions to suppress delayed flowering due to the presence of FRIGIDA, autonomous pathway mutations, or growth in noninductive photoperiods. efs mutants exhibit pleiotropic phenotypes, indicating that the role of EFS is not limited to the regulation of flowering time.

FRIGIDA-ESSENTIAL 1 interacts genetically with FRIGIDA and FRIGIDA-LIKE 1 to promote the winter-annual habit of Arabidopsis thaliana

Studies of natural variation have revealed that the winter-annual habit of many accessions of Arabidopsis is conferred by two genes, FRIGIDA (FRI) and FLOWERING LOCUS C (FLC), whose activities impose a vernalization requirement. To better understand the mechanism underlying the winter-annual habit, a genetic screen was performed to identify mutants that suppress the late-flowering behavior of a non-vernalized winter-annual strain. We have identified a locus, FRIGIDA-ESSENTIAL 1 (FES1), which, like FRI, is specifically required for the upregulation of FLC expression. FES1 is predicted to encode a protein with a CCCH zinc finger, but the predicted sequence does not otherwise share significant similarity with other known proteins. fes1 is a complete suppressor of FRI-mediated delayed flowering, but has little effect on the late-flowering phenotype of autonomous-pathway mutants. Thus, FES1 activity is required for the FRI-mediated winter-annual habit, but not for the similar phenotype resulting from autonomous-pathway mutations. Epistasis analysis between FES1, FRI and another specific suppressor of FRI-containing lines, FRIGIDA-LIKE 1 (FRL1), indicates that these genes do not function in a linear pathway, but instead act cooperatively to promote the expression of FLC.

SUPPRESSOR OF FRIGIDA3 encodes a nuclear ACTIN-RELATED PROTEIN6 required for floral repression in Arabidopsis

Flowering traits in winter annual Arabidopsis thaliana are conferred mainly by two genes, FRIGIDA (FRI) and FLOWERING LOCUS C (FLC). FLC acts as a flowering repressor and is regulated by multiple flowering pathways. We isolated an early-flowering mutant, suppressor of FRIGIDA3 (suf3), which also shows leaf serration, weak apical dominance, and infrequent conversion of the inflorescence shoot to a terminal flower. The suf3 mutation caused a decrease in the transcript level of FLC in both a FRI-containing line and autonomous pathway mutants. However, suf3 showed only a partial reduction of FLC transcript level, although it largely suppressed the late-flowering phenotype. In addition, the suf3 mutation caused acceleration of flowering in both 35S-FLC and a flc null mutant, indicating that SUF3 regulates additional factor(s) for the repression of flowering. SUF3 is highly expressed in the shoot apex, but the expression is not regulated by FRI, autonomous pathway genes, or vernalization. SUF3 encodes the nuclear ACTIN-RELATED PROTEIN6 (ARP6), the homolog of which in yeast is a component of an ATP-dependent chromatin-remodeling SWR1 complex. Our analyses showed that SUF3 regulates FLC expression independent of vernalization, FRI, and an autonomous pathway gene, all of which affect the histone modification of FLC chromatin. Subcellular localization using a green fluorescent protein fusion showed that Arabidopsis ARP6 is located at distinct regions of the nuclear periphery.

Making collaborative watershed management work: the confluence of state and regional initiatives

Initiatives in the Neponset, Ipswich, and Sudbury-Assabet-Concord watersheds highlight how watershed-scale innovation in engaging nongovernment participants is influenced, but not dominated, by the statewide program, the Massachusetts Watershed Initiative. The presence or absence of three elements--external support, process, and issue--and the order in which they occur, shape the viability of collaborative watershed-scale management initiatives. External support includes providing personnel or funding from outside an initiative. Process is the interaction among individuals undertaking watershed-wide policy development and/or implementation. An issue is an attention-requiring concern, vital to a watershed, that can most effectively be addressed by a coordinated strategy among different parties. A process generated by an issue is sustainable and amenable to enhancement through external support. The contribution of external support is most apparent when outside assistance is provided after an issue has crystallized into clear problem needs that can be addressed through specific research projects or implementation activities. Process is central in shaping issues, utilizing external support, and generating management results. The outcomes of voluntary processes in the three watershed initiatives highlight how the evolution of the Massachusetts Watershed Initiative leads to, and depends upon, the development of watershed-scale initiatives.

Molecular analysis of FRIGIDA, a major determinant of natural variation in Arabidopsis flowering time

Vernalization, the acceleration of flowering by a long period of cold temperature, ensures that many plants overwinter vegetatively and flower in spring. In Arabidopsis, allelic variation at the FRIGIDA (FRI) locus is a major determinant of natural variation in flowering time. Dominant alleles of FRI confer late flowering, which is reversed to earliness by vernalization. We cloned FRI and analyzed the molecular basis of the allelic variation. Most of the early-flowering ecotypes analyzed carry FRI alleles containing one of two different deletions that disrupt the open reading frame. Loss-of-function mutations at FRI have thus provided the basis for the evolution of many early-flowering ecotypes.

Renal sarcoidosis with superimposed postinfectious glomerulonephritis presenting as acute renal failure

We describe two patients with sarcoidosis with lesions of granulomatous interstitial nephritis (GIN) and postinfectious glomerulonephritis (GN). Both patients presented with heavy proteinuria, hematuria, and renal failure. Renal histology in both showed GIN and glomerular changes of proliferative GN with hump-like subepithelial deposits by electron microscopy of postinfectious GN. Antecedent history of pneumonia was present in one, and ASO titer was elevated in the other. The proteinuria and azotemia improved in both with steroid therapy. Reports of "postinfectious" or diffuse proliferative GN in patients with sarcoidosis are rare. The authors are unaware of reports of concomitant sarcoid GIN and postinfectious GN. Although acute renal insufficiency or failure can occur with GIN or other more common renal lesions primary glomerular disease should be considered in patients with sarcoidosis who present with renal dysfunction. This is a US government work. There are no restrictions on its use.

Nineteen eating disorder scales: Comparison by focus, ease, response format, and readability

Eating scales vary enormously in focus, ease, response format, and readability. As part of a larger study related to ethnicity and eating scales, we examined differences in eating scales to determine whether some scales may be more global and culture free in application than others. Ease of readability is related to the educational and cultural background of those to whom the scales are administered. Thus, 30 years of psychological literature (1968-1997) was reviewed; 40 eating disorder scales were found and requested from their authors. Using those who responded, 19 major scales were compared by focus, response format, validity, length, structure, reading level, and reading complexity. As expected, scales vary enormously in focus, length, content, and response format. Readability (as grade level) ranged from a high of 10.6 to a low of 1.1; 70% of the rated scales were rated as "highly readable."

Phasing the mirror segments of the Keck telescopes: the broadband phasing algorithm

To achieve its full diffraction limit in the infrared, the primary mirror of the Keck telescope (now telescopes) must be properly phased: The steps or piston errors between the individual mirror segments must be reduced to less than 100 nm. We accomplish this with a wave optics variation of the Shack-Hartmann test, in which the signal is not the centroid but rather the degree of coherence of the individual subimages. Using filters with a variety of coherence lengths, we can capture segments with initial piston errors as large as +/-30 microm and reduce these to 30 nm--a dynamic range of 3 orders of magnitude. Segment aberrations contribute substantially to the residual errors of approximately 75 nm.

Pulmonary function in children treated for rhabdomyosarcoma

Chemotherapy, radiation therapy, and surgical intervention have markedly improved the survival of patients treated for rhabdomyosarcoma. Unfortunately, the therapy may have deleterious effects on the lung. Pulmonary functions tests were obtained from 17 patients treated for rhabdomyosarcoma because of our concern regarding potential pulmonary dysfunction in this group of patients who had received bleomycin, which is known to be associated with lung injury. Mean age at the time of the diagnosis of rhabdomyosarcoma was 10.1 (+/- 7.2) years (range 0.01-23.5 years). The mean age at the time of pulmonary function testing was 17.0 (+/- 7.5) years (range 5.8-34.0 years). Study patients reportedly had no pulmonary symptoms. Approximately 87% of study patients had a restrictive ventilatory impairment on pulmonary function testing as measured by total lung capacity (TLC) values less than the lower limit of normal. Approximately 70% of study patients had carbon monoxide diffusing capacity (DLCO) values less than the lower limit of normal. There were no significant differences in pulmonary function parameters when male study patients were compared to female study patients. There was a statistically significant lower forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) ratio (P=0.03) and percent predicted forced expiratory flow at 25-75% of the FVC (FEF25-75; P=0.03) in the group of patients diagnosed with rhabdomyosarcoma over 8 years of age as compared to those individuals diagnosed under 8 years of age. In addition, there were no statistically significant differences in pulmonary function when the variables of sex and age at diagnosis (as outlined above) were studied in combination. In summary, we identified a high incidence of restrictive ventilatory abnormalities in a group of individuals (predominantly children) treated for rhabdomyosarcoma as well as a significantly lower FEV1/FVC ratio and percent predicted FEF25-75 in the group of patients diagnosed with the neoplasm over 8 years of age. Individuals caring for such patients are encouraged to obtain pre- and sequential posttreatment pulmonary function tests.

Monitoring AIDS and other rare population events: a network approach

This paper replicates and extends an earlier attempt to use data from the General Social Survey (GSS) to track the distribution of AIDS across demographic subgroups. (The GSS asks respondents whether they know a person with AIDS [PWA].) The gender, racial, age, and regional composition of the set of PWAs reported by GSS respondents is compared with that of the official AIDS cases reported to the Centers for Disease Control (CDC). In an attempt to assess the accuracy of the GSS estimates, a similar analysis is performed in which GSS respondents are asked whether they know a homicide victim. Data from four consecutive GSS samples (1988, 1989, 1990, and 1991) are used, permitting a more detailed exploration of potential biases and problems with the network technique. In addition, time series data from the National Health Interview Survey on the percentage of people who know at least one PWA are used to validate the GSS data. Our earlier findings, that the GSS identifies proportionately more White and midwestern cases than are reported to the CDC, are corroborated by the additional data. Possible explanations for these discrepancies are given, and suggestions are made for improving the utility of the approach.

Monitoring the AIDS epidemic in the United States: a network approach

Respondents in the 1988 General Social Survey (GSS) were asked to scan their acquaintance networks to identify all those who had been a victim of a homicide or had acquired immunodeficiency syndrome (AIDS). Estimates of the sex, race, age, and regional breakdowns for homicides in the last year and for people with AIDS were compared with official statistics. The GSS estimates for the distribution of homicide victims replicate the official statistics quite well. The GSS estimates for AIDS cases suggest that the data provided to the Centers for Disease Control may underestimate by a substantial margin the prevalence of AIDS in the white population of higher socioeconomic status, overstate the relative prevalence of the disease in the minority populations, underestimate the prevalence of the disease in the Midwest, and overstate it for the East.

Intrarenal renin-angiotensin system modulates glomerular angiotensin receptors in the rat

The aim of this study was to test the hypothesis that the intrarenal renin-angiotensin system (RAS) modulates glomerular angiotensin II (ANG II) receptors. In one protocol ANG II receptors were measured 7 days after unilateral denervation of the left kidney in rats. There were 50% more receptors in the glomeruli from denervated compared with innervated kidneys (right, 1,037 +/- 108 vs. left, 1,556 +/- 143 fmol/mg; P less than 0.01), which was associated with a 63% reduction (P less than 0.01) in left renal vein renin. The differences in ANG II receptors between the left and right kidneys were no longer present when angiotensin-converting enzyme was inhibited with enalapril or when pharmacological amounts of ANG II (50 ng/min) were infused. In a second protocol, renal cortical renin content was raised in the left kidney by placing a 0.20-mm clip on the left renal artery (two-kidney, one-clip Goldblatt model). At 7 days, glomerular ANG II receptors were reduced by 72.3% in the clipped compared with the contralateral kidneys (right, 1,232 +/- 105 vs. left, 341 +/- 170 fmol/mg; P less than 0.01). The differences in ANG II receptors were no longer present after enalapril treatment. Pharmacological maneuvers that either blocked ANG II formation or increased circulating ANG II resulted in an equal number of ANG II receptors in the right and left kidneys. The data indicate that the intrarenal RAS modulates the density of glomerular ANG II receptors and is a more important receptor modulator than plasma ANG II.

Effects of crystalloid and colloid fluids on extravascular lung water in hypoproteinemic dogs

We compared the effect of crystalloid to colloid fluid infusion on extravascular lung water (EVLW) in hypoproteinemic dogs. Plasmapheresis was used to decrease plasma colloid osmotic pressure (COP) to less than 40% of its base-line level. Five animals were then infused with 0.9% sodium chloride (saline), five with 5% human serum albumin (albumin), and five with 6% hydroxyethyl starch (hetastarch) to increase the pulmonary arterial occlusive pressure by 10 Torr in comparison to the postplasmapheresis level for a 5-h study interval. On completion of the procedure, the lungs were harvested and EVLW measured by the blood-free gravimetric technique. Three to six times the volume of saline compared with albumin or hetastarch (P less than 0.001) was infused. In the saline animals, COP was decreased to 3.3 +/- 1.3 Torr, whereas COP was increased to 18.1 +/- 1.4 Torr in albumin animals (P less than 0.001) and 20.1 +/- 1.6 Torr in the hetastarch group (P less than 0.001). The saline-treated dogs developed gross signs of systemic edema. The EVLW was 8.1 +/- 0.9 ml/kg in saline animals compared with 5.3 +/- 2.1 ml/kg in the albumin (P less than 0.05) and 4.1 +/- 1.4 ml/kg in the hetastarch (P less than 0.01) groups. These data indicate that crystalloid fluid infusion during hypoproteinemia is associated with the development of both systemic and pulmonary edema.

Comparison of blood lactate concentrations in central venous, pulmonary artery, and arterial blood

Arterial blood lactate is regarded as a very good indicator of the severity and prognosis of circulatory shock. Accordingly, the practical issue of whether such measurements might be equally valid on blood sampled from the right atrium or superior vena cava or from the pulmonary artery was investigated. In blood sampled prospectively on 50 occasions in 12 patients (group 1), arterial blood lactate ranged from 0.39 to 9.71 mmol/L. A very high correlation (r = .995) was observed between blood sampled simultaneously from an arterial and central venous catheter. The maximum absolute difference was 0.5, and mean difference 0.029 mmol/L. Comparable correlations were obtained between arterial and simultaneously sampled pulmonary artery blood (r = .994). We analyzed retrospectively the results of lactate analyses on 104 paired blood samples from the pulmonary artery and peripheral artery in 23 critically ill and injured patients (group 2) whose arterial blood lactates ranged from 0.46 to 12.99 mmol/L. We also found a high correlation (r = .998) between arterial and simultaneously sampled pulmonary artery blood lactate. The maximum absolute difference was 0.82, and the mean difference 0.03 mmol/L. These data demonstrate that lactate measurements in venous blood sampled either from a pulmonary artery or from a central venous catheter yield lactate concentrations essentially equivalent to those in arterial blood.

Isolation of intercalator-dependent protein-linked DNA strand cleavage activity from cell nuclei and identification as topoisomerase II

DNA intercalating agents such as 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA) have previously been found to induce in mammalian cells the formation of protein-associated DNA single- and double-strand breaks. In the current work, an activity characterized by the production of DNA-protein links associated with DNA strand breaks and by stimulation by m-AMSA was isolated from L1210 cell nuclei and was shown to be due to topoisomerase II. Nuclei were extracted with 0.35 M NaCl, and the extract was fractionated by gel filtration, DNA-cellulose chromatography, and glycerol gradient centrifugation. A rapid filter binding assay was devised to monitor the fractionation procedure on the basis of DNA-protein linking activity. The active DNA-cellulose fraction contained both topoisomerase I and topoisomerase II whereas the glycerol gradient purified material contained only topoisomerase II activity. The properties of the active material were studied at both stages of purification. m-AMSA enhanced the formation of complexes between purified topoisomerase II and SV40 DNA in which the DNA sustained a single- or double-strand cut and the enzyme was covalently linked to the 5' terminus of the DNA. This action was further enhanced by ATP, as well as by nonhydrolyzable ATP analogues. m-AMSA inhibited the topoisomerization and catenation reactions of topoisomerase II, probably because of trapping of the enzyme-DNA complexes. The activity showed a dependence on the type of DNA intercalators used, analogous to what was previously observed in intact cells. m-AMSA had no effect on topoisomerase I.(ABSTRACT TRUNCATED AT 250 WORDS)

Selective acidosis in venous blood during human cardiopulmonary resuscitation: a preliminary report

During experimental CPR, a marked venoarterial gradient in PCO2 has been reported. This is accompanied by a disproportionate decrease in venous pH and a simultaneous increase in arterial pH. This study includes a case report of human CPR in which simultaneous arterial and mixed venous blood gases were obtained before and after cardiac arrest. Similar venoarterial PCO2 gradients were observed subsequently in six additional patients during arrest. These clinical data indicate that arterial blood gases fail to reflect striking increases in venous PCO2 and decreases in pH due to respiratory acidosis on the venous side of the circulation.

Arterial blood gases fail to reflect acid-base status during cardiopulmonary resuscitation: a preliminary report

The American Heart Association's current standards for CPR indicate that acid-base therapy should be guided by measurements of arterial blood gases. However, we have discovered a striking discrepancy between arterial and venous blood gases during CPR: severe venous hypercarbia and acidosis may coexist with simultaneous arterial alkalosis. Arterial blood gases during CPR, therefore, may not accurately reflect the acid-base status of mixed venous blood and thus may fail to indicate systemic acid-base status.

Acid-base determinants of survival after cardiopulmonary resuscitation

The acid-base and electrolyte conditions which favor survival were examined in 105 patients during and after CPR. There was a sharp decrease in survival when arterial pH exceeded 7.55 during the initial 10 min after initiation of CPR. Measurements made one hour after successful resuscitation also demonstrated an increase in mortality when pH exceeded 7.55. Arterial blood lactate also served as a sensitive quantitative indicator of prognosis, both during and one hour after successful CPR. The adverse effects of alkalemia were largely explained by increases in whole-blood bicarbonate, plasma sodium, and plasma osmolality after administration of sodium bicarbonate.

Cooperative sequestration of m-AMSA in L1210 cells

The anticancer drug 4'-(9-acridinylamino)-methanesulfon-m-anisidide (m-AMSA) is known to bind to DNA by intercalation and to produce protein-associated DNA strand breaks in cells. Previous work [Zwelling et al., Biochemistry 20, 6553 (1981)] had shown that m-AMSA is in rapid equilibrium between extracellular and intracellular compartments, and that the DNA strand breaks exist in a steady state of rapid formation and resealing. The current work reports an unusual uptake phenomenon of m-AMSA by mouse leukemia L1210 cells that occurs at higher drug concentrations than previously studied. The new uptake phenomenon was characterized by cooperativity, hysteresis, irreversibility, saturability, slowness and temperature dependence. It is concluded that m-AMSA concentrations above a critical value can initiate the irreversible sequestration of m-AMSA into a new phase, probably in an extranuclear compartment of the cell, from which the drug has no access to the nuclear DNA and probably does not contribute to cytotoxicity.

Formation and resealing of intercalator-induced DNA strand breaks in permeabilized L1210 cells without the stimulated synthesis of poly(ADP-ribose)

DNA strand breaks produced by damaging agents such as x-ray generally stimulate poly(adenosine diphosphoribose) (ADP-R) synthesis in mammalian cells. DNA intercalating agents induce the formation of strand breaks which are unusual in that they are associated with tightly or covalently bound protein. In order to determine whether the intercalator-induced strand breaks are associated with poly-(ADP-R) synthesis, L1210 cells were treated with the intercalating agent, 4'-(9-acridinylamino)methanesulfon-m-anisidide. Poly(ADP-R) synthesis, measured by [3H]NAD incorporation following cell permeabilization, was enhanced in x-irradiated cells, but not in cells exposed to 4'-(9-acridinylamino)methanesulfon-m-anisidide at doses which produced equivalent strand breaks frequencies. The permeabilized cell system did not support DNA synthesis and x-ray-induced strand breaks did not reseal. The intercalator-induced strand breaks, however, resealed within 10 min. Hence, the strand breaks observed in intercalator-treated cells may not constitute DNA damage in the usual sense. The resealing of intercalator-induced DNA breaks in the absence of DNA or poly(ADP-R) synthesis is unique among chemical or physical agents which produce DNA scissions.

Cytotoxicity and DNA strand breaks by 5-iminodaunorubicin in mouse leukemia L1210 cells: comparison with adriamycin and 4'-(9-acridinylamino)methanesulfon-m-anisidide

The effects upon cellular DNA and cytotoxicity produced by the anthracyclines 5-iminodaunorubicin and Adriamycin were studied in mouse leukemia L1210 cells. 5-Iminodaunorubicin produced protein-concealed DNA strand breaks as measured by alkaline elution as had other intercalators including Adriamycin. 5-Iminodaunorubicin produced DNA breaks more efficiently than did Adriamycin despite a lower potency for free radical formation. Many of the 5-iminodaunorubicin breaks measured in this assay may arise from apposed single-strand breaks (i.e., double-strand breaks). 5-Iminodaunorubicin produced breaks which disappeared within 1 to 2 hr following drug removal and were in this way similar to the breaks produced by the acridine intercalator 4'-(9-acridinylamino)methanesulfon-m-anisidide. Adriamycin produced more persistent breaks. Despite similarities in the kinetics of break disappearance, 5-iminodaunorubicin produced greater cytotoxicity than did 4'-(9-acridinylamino)methanesulfon-m-anisidide when compared at doses producing equal single-strand or double-strand breaks. Differences in the ratio of single-strand breaks to double-strand breaks and the associated cytotoxicity for 5-iminodaunorubicin and 4'-(9-acridinylamino)methanesulfon-m-anisidide indicate that a different mechanism is probably involved in the DNA break production by each agent. Differences between the cytotoxicity associated with the DNA break production by two agents with similar break disappearance kinetics indicate that intercalator-induced DNA breaks cannot be a uniformly lethal DNA lesion.

Measurement of whole blood osmolality

When plasma osmolality exceeds 350 milliosmoles per kilogram of plasma water during cardiopulmonary resuscitation, a disproportionate increase in mortality is observed. The increase of plasma osmolality is in part related to the administration of sodium bicarbonate. If iatrogenic risks of alkali therapy are to be minimized, repetitive measurements of plasma osmolality are advised. Therefore, the authors investigated a rapid method for determining osmolality, in which whole blood rather than plasma was utilized, thereby obviating the time required for erythrocyte separation. This study demonstrated that the difference between osmolality measured on whole blood and that measured on plasma were comparable to duplicate measurements of osmolality on plasma. The authors conclude that osmolality measured on whole blood serves as a reliable and accurate estimate of plasma osmolality.

Protein-associated deoxyribonucleic acid strand breaks in L1210 cells treated with the deoxyribonucleic acid intercalating agents 4'-(9-acridinylamino) methanesulfon-m-anisidide and adriamycin

The DNA intercalating agents 4'-(9-acridinyl-amino) methanesulfon-m-anisidide (m-AMSA) and adriamycin were studied by using filter elution methods to measure DNA single-strand breaks (SSB's), DNA-protein cross-links (DPC's), and double-stranded breaks (DSB's) in mouse leukemia L1210 cells. Both compounds produced SSB's and DPC's at nearly 1:1 ratios. The SSB's and DPC's were shown to be localized with respect to each other; this was inferred from the finding that filter assays based on protein adsorption completely prevented the elution of the DNA single-strand segments between SSB's. In the case of m-AMSA, which produces relatively high frequencies of DNA lesions, the possibility that a protein bridges across the SSB was excluded by alkaline sedimentation studies. Both compounds also produced DSB's, but the SSB/DSB ratios differed; the SSB/DSB ratios increase in the following order: ellipticine greater than adriamycin greater than m-AMSA greater than X-ray [results of this paper combined with those of Ross, W. E., & Bradley, M. O. (1981) Biochim. Biophys. Acta (in press)]. The o-AMSA isomer is much less cytotoxic than m-AMSA and did not produce protein-associated strand breaks. The simplest model to explain the results is that a protein becomes covalently bound to either the 3' or the 5' termini of the intercalator-induced strand breaks. At moderately cytotoxic doses, m-AMSA yielded much larger frequencies of protein-associated SSB's than did adriamycin. m-AMSA-induced protein-associated SSB's saturated at approximately 60000 per cell over a concentration range in which m-AMSA uptake by the cells was proportional to the drug concentration. m-AMSA was found to enter and exit from cells very rapidly at 37 degrees C; protein-associated SSB's and DSB's also appeared and disappeared rapidly. At reduced temperature, however, the appearance and disappearance of protein-associated SSB's could be blocked while m-AMSA entry and exit still occurred. The saturation behavior and temperature dependence suggest that the formation and disappearance of protein-associated strand breaks is enzymatic. The simplest hypothesis is that the linked protein is a nuclease, such as a topoisomerase, which becomes bound to one terminus of the strand break it produces. It is proposed that topoisomerases producing SSB's and DSB's are stimulated to different degrees by different intercalators.

Clinical and experimental studies on electromechanical dissociation

Electromechanical dissociation (EMD) is the most frequent cause of unsuccessful cardiac resuscitation in critically ill patients. In a clinical study of cardiac arrest, including 54 episodes in 50 fully monitored patients, 14 episodes of ventricular fibrillation were observed and seven were reversed. In the remaining 40 instances, 36 cases of EMD were initially observed. Four patients had asystole. None of the patients with EMD or asystole were successfully resuscitated. For objective study of EMD and its treatment, we developed an experimental model in which ventricular fibrillation was induced in mechanically ventilated dogs. EMD was predictably observed when, after an interval of 120 seconds, ventricular fibrillation was reversed with an external countershock. Neither metabolic acidosis nor metabolic alkalosis modified the incidence of EMD. A few dogs were pretreated with glucose-insulin-potassium or pharmacologic doses of methylprednisolone, but this did not clearly reduce the incidence of EMD. However, the onset of EMD was delayed when the body temperature of the animal was spontaneously reduced.

The stat laboratory: facilitating blood gas and biochemical measurements for the critically ill and injured

The stat laboratory has evolved to fulfill the need for rapidly available laboratory data in support of clinical decision-making af the bedside of the critically ill or injured patient. The operation of a stat laboratory, which was first organized more than 12 years ago, is described. Methods of organization, instrumentation, technics and sequencing of analyses, and costs for a standard panel of stat laboratory measurements on arterial or mixed venous blood are described. In addition to blood gases, measurements include hematocrit, hemoglobin, oxygen saturation, methemoglobin, carboxyhemoglobin, blood lactate, plasma electrolytes, plasma osmolality, plasma colloid osmotic pressure, and estimated plasma protein content. The panel of tests is completed and reported within 11 min after a 5-ml sample of arterial or mixed venous blood is delivered to the laboratory.

An "oncometer" of clinical measurement of colloid osmotic pressure of plasma

Measurement of colloid osmotic pressure complements measurements of pulmonary artery wedge pressure for assessing the risks of pulmonary edema and constitutes an increasingly important reference for purposes of guiding selection of colloid or crystalloid fluids in patients with acute cardiac disease. We describe a simple device for its routine clinical measurement. A membrane, selectively impermeable to molecules of relative molecular mass (Mr) greater than 30000, is rigidly mounted between a sample chamber and a reference chamber filled with isotonic saline. A pressure transducer measures the negative pressure developed in the reference chamber and displays it on a digital panel meter. The sensor chamber accommodates samples of 50 to 300 microliter. Equilibration is completed within 2 min. A control solution of human serum albumin (50 g/liter) is measured to confirm the accuracy of calibration of the system, with reproducible readings of 25.9 g/cm2 within one SD (equivalent to 0.4 g/cm2). Technical simplicity of operation and modest costs of disposables have made feasible the routine measurement of colloid osmotic pressure.

An "oncometer" of clinical measurement of colloid osmotic pressure of plasma

Measurement of colloid osmotic pressure complements measurements of pulmonary artery wedge pressure for assessing the risks of pulmonary edema and constitutes an increasingly important reference for purposes of guiding selection of colloid or crystalloid fluids in patients with acute cardiac disease. We describe a simple device for its routine clinical measurement. A membrane, selectively impermeable to molecules of relative molecular mass (Mr) greater than 30000, is rigidly mounted between a sample chamber and a reference chamber filled with isotonic saline. A pressure transducer measures the negative pressure developed in the reference chamber and displays it on a digital panel meter. The sensor chamber accommodates samples of 50 to 300 microliter. Equilibration is completed within 2 min. A control solution of human serum albumin (50 g/liter) is measured to confirm the accuracy of calibration of the system, with reproducible readings of 25.9 g/cm2 within one SD (equivalent to 0.4 g/cm2). Technical simplicity of operation and modest costs of disposables have made feasible the routine measurement of colloid osmotic pressure.

Relationship between colloid osmotic pressure and pulmonary artery wedge pressure in patients with acute cardiorespiratory failure

Close relationships between progressive respiratory failure, roentgenographic signs of pulmonary opacification and decreases in the difference between colloid osmotic pressure of plasma and the pulmonary artery wedge pressure (colloid-hydrosatic pressure gradient) were demonstrated in 49 critically ill patients with multisystem failure, in patients in shock. The potential importance of this relationship is underscored by the observation that fatal progression of pulmonary edema was related to a critical reduction in the colloid-hydrostatic pressure gradient to levels of less than 0 mm Hg. More often, reduction in colloid osmotic pressure rather than increases in left ventricular filling pressure (pulmonary artery wedge pressure) accounted for the decline in colloid-hydrostatic pressure gradient. Routine measurement of colloid osmotic pressure, preferably in conjunction with pulmonary artery wedge pressure, is likely to improve understanding of the mechanisms of acute pulmonary edema.

In vitro changes in blood P50 and erythrocyte 2,3-diphosphoglycerate concentration

We studied in vitro changes in P50 and erythrocyte 2,3-diphosphoglycerate concentration occurring in blood 2 to 8 h after venipuncture. When blood was incubated at 37 degrees C, significant decreases in P50 were observed at 2, 4, and 8 hr. Such a change was significantly less when blood was kept at 4 degrees C. The rate of decrease in P50 was not changed when pH was altered by adding either lactic acid or sodium bicarbonate to the blood before incubation at 37 degrees C for 2 h. The erythrocyte 2,3-diphosphoglycerate concentration of blood incubated at 37 degrees C did not change by 2 h, but had significantly decreased by 4 h. To avoid in vitro changes, we recommend that P50 be determined as soon as possible for blood sampling.