Imaging protein kinase Calpha activation in cells

Spatially resolved fluorescence resonance energy transfer (FRET) measured by fluorescence lifetime imaging microscopy (FLIM), provides a method for tracing the catalytic activity of fluorescently tagged proteins inside live cell cultures and enables determination of the functional state of proteins in fixed cells and tissues. Here, a dynamic marker of protein kinase Calpha (PKCalpha) activation is identified and exploited. Activation of PKCalpha is detected through the binding of fluorescently tagged phosphorylation site-specific antibodies; the consequent FRET is measured through the donor fluorophore on PKCalpha by FLIM. This approach enabled the imaging of PKCalpha activation in live and fixed cultured cells and was also applied to pathological samples.

Lead and copper contamination of soil from industrial activities and firing ranges

Lead still remains one of the most thoroughly investigated heavy metals in the environment. Although the identification of lead in soil is a routine matter, its environmental consequence is still much debated because of its potential mobility. We have investigated lead- and copper-contaminated soil from two different areas. One was in an urban area, which formerly had a lead smelter within the city. The other a firing range, in which hundreds of thousands of rounds were fired into a very large mound known as a berm. Homogeneity tests, depth profiles, and Pb-Cu correlations are discussed.

Use of a clinical model for safe management of patients with suspected pulmonary embolism

BACKGROUND

The low specificity of ventilation-perfusion lung scanning complicates the management of patients with suspected pulmonary embolism.

OBJECTIVE

To determine the safety of a clinical model for patients with suspected pulmonary embolism.

DESIGN

Prospective cohort study.

SETTING

Five tertiary care hospitals.

PATIENTS

1239 inpatients and outpatients with suspected pulmonary embolism.

INTERVENTIONS

A clinical model categorized pretest probability of pulmonary embolism as low, moderate, or high, and ventilation-perfusion scanning and bilateral deep venous ultrasonography were done. Testing by serial ultrasonography, venography, or angiography depended on pretest probability and lung scans.

MEASUREMENTS

Patients were considered positive for pulmonary embolism if they had an abnormal pulmonary angiogram, abnormal ultrasonogram or venogram, high-probability ventilation-perfusion scan plus moderate or high pretest probability, or venous thromboembolic event during the 3-month follow-up. All other patients were considered negative for pulmonary embolism. Rates of pulmonary embolism during follow-up in patients who had a normal lung scan and those with a non-high-probability scan and normal serial ultrasonogram were compared.

RESULTS

Pretest probability was low in 734 patients (3.4% with pulmonary embolism), moderate in 403 (27.8% with pulmonary embolism), and high in 102 (78.4% with pulmonary embolism). Three of the 665 patients (0.5% [95% CI, 0.1% to 1.3%]) with low or moderate pretest probability and a non-high-probability scan who were considered negative for pulmonary embolism had pulmonary embolism or deep venous thrombosis during 90-day follow-up; this rate did not differ from that in patients with a normal scan (0.6% [CI, 0.1% to 1.8%]; P > 0.2).

CONCLUSION

Management of patients with suspected pulmonary embolism on the basis of pretest probability and results of ventilation-perfusion scanning is safe.

Multicultural considerations in the use of advance directives

PURPOSE/OBJECTIVES

To describe advance directives and the Patient Self-Determination Act (PSDA), to explore the European American sociocultural values underlying advance directives, and to describe the ethical and cultural issues that arise when attempting to encourage and use advance directives in culturally diverse populations.

DATA SOURCES

Research articles, case studies, and theoretical articles from clinical and bioethical literature.

DATA SYNTHESIS

An overview of advance directives and the PSDA is provided. The European American cultural values underlying advance directives are reviewed and contrasted with sociocultural values of culturally diverse groups to raise the question of cross-cultural applicability of advance directives and European-based bioethics.

CONCLUSIONS

The sociocultural values of many culturally diverse groups conflict with the values on which the use of advance directives is based. Thus, working with end-of-life decisions and advance directives for people from culturally diverse groups may be problematic.

IMPLICATIONS FOR NURSING PRACTICE

Nurses should be sensitive to sociocultural beliefs that influence decisions affecting end-of-life care, especially the use of advance directives. Practitioners must incorporate this knowledge to increase flexibility of institutional practices and standards of care in the application of advance directives.

Structural and kinetic evidence for strain in biological catalysis

A classic hypothesis for enzyme catalysis is the induction of strain in the substrate. This notion was first expressed by Haldane with the lock and key analogy-"the key does not fit the lock perfectly but exercises a certain strain on it" (1). This mechanism has often been invoked to explain the catalytic efficiency of enzymes but has been difficult to establish conclusively (2-7). Here we describe X-ray crystallographic and mutational studies of an antibody metal chelatase which strongly support the notion that this antibody catalyzes metal ion insertion into the porphyrin ring by inducing strain. Analysis of the germline precursor suggests that this strain mechanism arose during the process of affinity maturation in response to a conformationally distorted N-alkylmesoporphyrin.

Medical readiness training exercise in El Salvador, Central America, 1996

Medical Readiness Training Exercises (MEDRETEs) can be a valuable training tool for U.S. Army personnel in remote areas of deployment. We report our experience of the MEDRETE in El Salvador in 1996. Working with foreign physicians of the host country was a positive experience in which we learned local customs and mutual cooperation. Evaluation and treatment of nearly 6,000 patients increased goodwill in the community and provided an opportunity for teamwork for Army Reserve medical units, including increased discussions of public health issues. We also report on the field applicability of the advanced laboratory and pharmacy equipment we included in our training.

PTR3, a novel gene mediating amino acid-inducible regulation of peptide transport in Saccharomyces cerevisiae

We have isolated and characterized the Saccharomyces cerevisiae PTR3 gene by functional complementation of a mutant deficient for amino acid-inducible peptide transport. PTR3 is predicted to encode a protein of 678 amino acids that exhibits no similarity to any other protein in the database. Deletion of the PTR3 open reading frame pleiotropically reduced the sensitivity to toxic peptides and amino acid analogues. Initial rates of radiolabelled dipeptide uptake demonstrated that elimination of PTR3 resulted in the loss of amino acid-induced levels of peptide transport. PTR3 was required for amino acid-induced expression of PTR2, the gene encoding the dipeptide/tripeptide transport protein, but was not necessary for nitrogen catabolite repression of peptide import or PTR2 expression. It was determined that PTR3 also modulates expression of BAP2, the gene encoding the branched-amino acid permease. Furthermore, we present genetic evidence that suggests that PTR3 functions within a novel regulatory pathway that facilitates amino acid induction of the PTR system.

Schizosaccharomyces pombe isp4 encodes a transporter representing a novel family of oligopeptide transporters

We have recently cloned an oligopeptide transport gene from Candida albicans denoted OPT1. This gene showed significant sequence similarity to three open reading frames (ORFs) with no previously established function: isp4 from Schizosaccharomyces pombe and Saccharomyces cerevisiae YJL212C and YPR194C, identified during the genome project. The S. pombe gene isp4 was originally identified by Sato et al. as a gene that was upregulated through nitrogen starvation induction of meiosis. However, an isp4delta strain exhibited a wild-type phenotype with respect to sexual differentiation. We have found that the same isp4delta strain is deficient in tetrapeptide transport activity as measured by its resistance to toxic tetrapeptides, by its inability to accumulate a radiolabelled tetrapeptide and by the inability to use tetrapeptides as a sole source of an amino acid to satisfy an auxotrophic requirement. Similarly, we found that the ORF YPR194C from S. cerevisiae encodes an oligopeptide transporter. Sequence analyses as well as physiological evidence has led us to propose that the proteins encoded by isp4 and the genes identified from S. cerevisiae and C. albicans comprise a new group of transporters specific for small oligopeptides, which we have named the OPT family.

Stromelysin 3: an independent prognostic factor for relapse-free survival in node-positive breast cancer and demonstration of novel breast carcinoma cell expression

Stromelysin 3 (ST3) is a matrix metalloproteinase implicated in mammary carcinoma progression. To date, localization of ST3 expression in breast cancer by in situ hybridization and immunocytochemistry has shown that the expression of the enzyme is limited to only the stromal fibroblasts surrounding the cancer cells. We have immunostained a large group of ductal carcinoma in situ and invasive breast carcinomas using a monoclonal antibody (5ST-4A9) raised against the hemopexin-like domain of human ST3. We show that invasive lobular carcinomas express significantly less ST3 than invasive ductal carcinomas (IDCs) (P = 0.002). We also show, for the first time, that certain breast carcinoma cells that have undergone a degree of epithelial-to-mesenchymal transition, the so-called metaplastic carcinomas, can express ST3 mRNA and protein, which may in part explain the increased metastatic propensity seen in a number of these tumors. In addition, patients with IDC who had moderate to strong ST3 levels had significantly shorter disease-free survival than those with negative or weak ST3 levels (P = 0.02). Furthermore, in node-positive IDC patients, multivariate analysis revealed that ST3 level was a strong, independent prognostic parameter for disease-free survival (P = 0.005).

Identification of missense and truncating mutations in the BRCA1 gene in sporadic and familial breast and ovarian cancer

The cloning of the breast and ovarian cancer susceptibility gene, BRCA1, allows direct estimation of the proportion of these cancers in the general population which can be attributed to germline mutations in this gene. We have used a combination of SSCP, heteroduplex analysis, and chemical cleavage of mismatch to screen the BRCA1 gene for mutations in the germline of 42 patients with breast or ovarian cancer who either have a moderate family history of these cancers, or have no family history of malignancy but a very early onset of the disease. A total of 30 sequence variants were observed, eight of which have not been described previously. Three sequence changes detected by chemical cleavage or heteroduplex analysis were missed by SSCP. The variants included 13 missense mutations, which were assessed for their pathogenic implications. Two of these (M18T and A1708E) are nonconservative substitutions which are located in evolutionarily conserved regions of the gene: M18T lies just upstream of the RING finger motif, and A1708E abolishes the transcriptional transactivation activity of the carboxy-terminal region of BRCA1. Mutations were observed in eight patients overall (19.0%), and protein-truncating mutations occurred in five of 27 (18.5%) families with 1-3 cases of breast or ovarian cancer. The data suggest that a significant proportion of patients with a modest or no family history of these cancers may carry germline mutations in BRCA1.

A microsatellite within the MUC1 locus at 1q21 is altered in the neoplastic cells of breast cancer patients

Paired DNA samples from the neoplastic and nonneoplastic cells of 118 patients with the sporadic, nonfamilial form of breast cancer were analyzed for evidence of genetic alteration at a polymorphic microsatellite mapped to intron 6 within the MUC1 gene at 1q21. Two other microsatellite loci, D1S104 and APO-A2, which also map to 1q21, were analyzed as well. The frequency of alteration at the microsatellite within the MUC1 locus was significantly higher than D1S104 or APO-A2 (P < 0.001). Analysis by Southern blotting of the VNTR region of the MUC1 gene revealed an amplification of one allele in 34 of 54 informative cases (63%). There was no significant association between these alterations and alterations of the microsatellite within the same locus, suggesting independent mechanisms were responsible for the genetic changes. Microsatellite loci D17S579 at 17q21, the site of the BRCA1 gene, and D18S34 at 18q21-qter, the deleted in colorectal cancer locus, were also analyzed by PCR. Alterations at D17S579 and D18S34 were detected in 18.8% and 6.2% of patients, respectively (P < 0.001, and P < 0.1 relative to the frequency of alteration at D1S104 or APO-A2). A previously described polymorphism of hMSH2 was altered in 16.4% of cases.

Effect of dietary dl-alpha-tocopherol on tissue alpha- and gamma-tocopherol and pulmonary hypertension syndrome (ascites) in broilers

The objectives of this experiment were to determine the effects of high dietary levels of vitamin E on growth performance and pulmonary hypertension syndrome (PHS) mortality. Male broiler chicks (Cobb 500) were randomly assigned to one of four dietary treatments consisting of standard starter and grower diets supplemented with 0, 17, 46, and 87 mg dl-alpha-tocopherol acetate/kg. To encourage the development of PHS, air temperature in the house was 32 and 28 C for Weeks 1 and 2, dropped to 18 C during Week 3, and kept between 10 and 15 C during Weeks 4 through 7. Also, chicks were placed in floor pens on litter used for five previous flocks and ventilation reduced to increase dust and ammonia in the house. Ammonia levels increased from an initial 18 to 36 ppm on Day 42 with the increase in ammonia corresponding to an obvious increase in dust in the air. Lung and liver tissue obtained at 2, 5, and 7 wk of age were analyzed for tissue alpha- and gamma-tocopherol by liquid chromatography. Dietary vitamin E had no effect on body weight, feed intake, or feed efficiency. Cumulative PHS mortality through 7 wk of age was 21% and was also unaffected by dietary treatment. Liver and lung alpha-tocopherol concentrations exhibited a dose-response increase to dietary tocopherol and there was a high correlation between lung and liver tissue alpha-tocopherol (r = 0.72, P < 0.05). Whereas gamma-tocopherol concentrations in lung and liver were unaffected by dietary treatment, liver and lung exhibited age-dependent increases in both alpha- and gamma-tocopherol. Despite dose-dependent increases in tissue alpha-tocopherol, supplementation of diets with up to 87 mg dl-alpha-tocopherol acetate had no effect on growth performance or PHS mortality in broilers under the conditions used in this study.

Spinal rigidity following acute myelitis

A patient with a 2(1/2)-year history of painful spasms and rigidity of both lower limbs is described. Symptoms began after an episode of acute myelitis. The spasms--which were spontaneous and stimulus sensitive and occurred on voluntary action--involved the repetitive grouped discharge of motor units. Continuous motor unit activity was present at rest in the muscles of both legs, and cutaneomuscular reflexes were abnormal. This patient is similar to those recently reported as having stiffness and spasms of the legs due to a possible chronic spinal interneuronitis and provides further evidence that this kind of movement disorder may be caused by spinal cord pathology.

A randomized clinical trial of ursodeoxycholic acid as adjuvant treatment to prevent liver transplant rejection

Acute rejection following orthotopic liver transplantation is a common problem despite current immunosuppressive regimens. Ursodeoxycholic acid (UDCA) has been shown in small, open-labeled studies to prevent rejection episodes, although its effects on complications such as infections, length of hospital stay, and survival have not been evaluated. We conducted a randomized, placebo-controlled, double-blind trial to determine if UDCA (10-15 mg/kg/d) added to a cyclosporine-based immunosuppressive regimen was associated with a decrease in the incidence of at least one episode of acute cellular rejection. Secondary end-points included determining differences in the total number of rejection episodes, the use of muromonab-CD3, the incidence of infections, length of hospital stay, and survival at 90 days and 1 year. Fifty-two patients were randomized, 28 to the treatment group and 24 to the placebo group. During the 3 months of the trial, there was no difference between the placebo and UDCA groups in the number of patients who were rejection-free; however, there were significantly fewer patients in the treatment group who had multiple episodes of acute rejection (0 vs. 6; P = .007). Patients in the treatment group experienced a significantly lower incidence of bacterial infections (4% vs. 29%; P = .02), shorter hospital stay (25 days vs. 34 days; P = .03), and better 90-day survival (100% vs. 83%; P = .04) and 1-year survival (93% vs. 79%). The addition of UDCA to a cyclosporine-based immunosuppressive regimen results in significantly fewer patients experiencing multiple episodes of rejection and improved survival at 90 days and at 1 year. The use of UDCA as adjuvant therapy for patients undergoing liver transplantation who are treated with a cyclosporine-based immunosuppressive regimen should be considered.

Functional equivalence in children: derived stimulus-response and stimulus-stimulus relations

The present study investigated the simultaneous occurrence of emergent stimulus-response relations (functional equivalence) and stimulus-stimulus relations (stimulus equivalence). After being pretrained and tested on two symbolic match-to-sample tasks (X1-Y1, X2-Y2), 20 4- and 5-year-old children were trained to emit specified responses to pairs of stimuli (A1-R1, B1-R1, A2-R2, B2-R2) in one setting (original training) and to emit other responses to one member of each pair (A1-R3, A2-R4) in another setting (reassignment training). Of the 18 children who responded correctly on all trained tasks, 15 emitted the novel responses also in the presence of the nonreassigned stimuli (B1-R3, B2-R4). Eleven of these children also matched same-class stimuli with one another (A1-B1, A2-B2, and vice versa). Additional tests with four of these children documented the formation of conditional response-stimulus relations (R3-B1, R4-B2) in all four children, and of conditional response-response relations (R1-R3, R2-R4, and vice versa) in two of them. Children who did not show stimulus control transfer also failed to match same-class stimuli with one another. Present findings, together with those obtained in animal research, suggest that functional equivalence can imply but does not require stimulus equivalence.

Emergent conditional discriminations in children and adults: stimulus equivalence derived from simple discriminations

This study examines whether trained and derived simple discriminations lead to conditional relations between discriminative stimuli of the same and opposite (S+, S-) functions. After being trained on an arbitrary X-Y task (X1-Y1, X2-Y2) and on two simple discrimination tasks (A1+/A2- and B1+/B2-), children (Experiment 1) and adults (Experiment 2) were tested on the formation of novel simple discriminations (A3+/A2- and B3+/B2-) and conditional stimulus relations between all directly and indirectly paired A stimuli and between all directly and indirectly paired B stimuli (A1-A2-A3, B1-B2-B3). Subjects who formed these sets also received A2-X1 and B1-X2 training followed by a series of probes to assess the formation of two five-member stimulus equivalence classes (A1-A2-A3-X1-Y1, B1-B2-B3-X2-Y2). A modest majority of the children matched the directly paired stimuli (A2-A1, B2-B1 and A1-A2, B1-B2; A2-A3, B2-B3 and A3-A2, B3-B2) with one another while only a few of them also matched the indirectly paired stimuli with one another (A1-A3, B1-B3 and A3-A1, B3-B1). Those who did also related all the A and B stimuli with the designated X and Y stimuli. By contrast, all normal adults matched all paired and conditionally linked stimuli with one another. Present findings and those of related studies on stimulus equivalence are discussed from a stimulus contiguity perspective.

Characterization of dynamic 3-D PET imaging for functional brain mapping

Methods for optimizing the acquisition, reconstruction and analysis of positron emission tomography (PET) images for functional brain mapping have been investigated. The scatter fraction and noise-equivalent count rate characteristics were measured for the ECAT 951/31R PET scanner operating in septa-extended two-dimensional (2-D) and septa-retracted three-dimensional (3-D) modes. The 3-D mode is shown to provide higher signal-to-noise images than the 2-D mode at specific activities less than 30 kBq/ml. To enable increased temporal resolution in dynamic 3-D PET activation studies, a parallel version of the 3-D reconstruction algorithm was developed. Implementation of the reprojection algorithm on an 88 processor 1860 supercomputer resulted in a more than tenfold increase in reconstruction speed compared to a single 1860 processor system. An investigation of the optimal duration for imaging brain activations was undertaken in 12 normal subjects using repeated H2(15)O slow infusions and a visually presented lexical decision task. The significance of change in regional cerebral blood flow (CBF) was determined using statistical parametric maps for images acquired during stimulation, immediately after stimulation, and commencing 1 min after cessation of the stimulus. Regions of CBF change were detected in all three images. Dynamic 3-D, or four-dimensional (4-D), PET activation scanning is shown to be practical and likely to further improve the sensitivity of PET for detection of subtle regional CBF changes in functional brain mapping research.

A transformation of respondently conditioned stimulus function in accordance with arbitrarily applicable relations

Adult male subjects saw a sexual film clip paired with a nonsense syllable (C1). Similarly, an emotionally neutral film clip was paired with a second nonsense syllable (C3). Responses to the nonsense syllables were recorded as skin resistance responses. Subjects were also trained in a series of related conditional discriminations, using the C1 and C3 stimuli, from which the following equivalence relations were predicted; A1-B1-C1, A2-B2-C2, and A3-B3-C3. Some subjects were given matching-to-sample (equivalence) tests after the conditional discrimination training (Experiment 1), whereas others were not (Experiment 2). Subjects were tested for a transformation of eliciting functions by presenting the A1 and A3 stimuli, which were related through equivalence to C1 and C3, respectively. Five of the 6 subjects who showed significantly greater conditioned responses to C1 than to C3, also showed significantly greater skin resistance responses to A1 than to A3. Two additional subjects demonstrated a transformation of an eliciting stimulus function in accordance with five-member equivalence relations (Experiment 3), and another 5 subjects demonstrated similar effects in accordance with the relations of sameness and opposition (Experiment 4).

Randomised trial of oral and intravenous methylprednisolone in acute relapses of multiple sclerosis

BACKGROUND

An intravenous rather than oral course of methylprednisolone is often prescribed for treating acute relapses in multiple sclerosis (MS) despite the lack of evidence to support this route of administration. Our double-blind placebo-controlled randomised trial was designed to compare the efficacy of commonly used intravenous and oral steroid regimens in promoting recovery from acute relapses in MS.

METHODS

42 patients with clinically definite relapse in MS received oral, and 38 intravenous, methylprednisolone. Clinical measurements at entry and at 1 week, 4 weeks, 12 weeks, and 24 weeks included Kurtzke's expanded disability status scale (EDSS), Hauser's Ambulatory Index, and an arm-function index. The primary outcome criterion was a difference between the two treatment groups of one or more EDSS grades at 4 weeks.

FINDINGS

There were no significant differences between the two groups at any stage of the study in any measurement taken: the mean difference in EDSS at 4 weeks (adjusted for baseline level) was 0.07 grades more in those taking oral steroids (95% CI -0.46 to 0.60). The most optimistic outcome for intravenous therapy is an average benefit of less than half a grade improvement on EDSS over oral treatment.

INTERPRETATION

Since our study did not show any clear advantage of the intravenous regime we conclude that it is preferable to prescribe oral rather than intravenous steroids for acute relapses in MS for reasons of patient convenience, safety, and cost.

Cloning, sequencing, and embryonic expression of an N-ras proto-oncogene isolated from an enriched zebrafish (Danio rerio) cDNA library

An enriched zebrafish (Danio rerio) complementary DNA library was constructed for screening of ras-related genes, and a positive clone was isolated from one plate of 3 x 10(4) plaques. This clone, Zras-B1, carried an insert of 2592 base pairs (bp) with an open reading frame encoding a ras p21 protein of 188 amino acids. The deduced amino-terminal 86 amino acid residues and the carboxy-terminal CAAX binding motif are identical to mammalian ras. The full-length Zras-B1-encoded protein is most closely related to human N-ras (91% identity), with lesser homology to Ha-ras (84%) and Ki-ras (85%). Preliminary screening data also indicate other ras genes in zebrafish, at least one of which is also transcribed in adults. A Zras-B1-related 3.1-kb transcript was found to be abundant in embryos from zygote through gastrulation, and may be maternally derived.

An investigation into the temperature dependence of the rheological synergy between xanthan gum and locust bean gum mixtures

The interaction between xanthan gum (XG) and locust bean gum (LBG) in water has been investigated using texture analysis, thermorheological analysis and high sensitivity differential scanning calorimetry. For the batches of XG and LBG used in the present study and at a total polymer concentration of 1% w/v, texture analysis indicated that the greatest synergy occurred at approximately 10% w/w XG, while the technique also allowed measurement of the increase in strength resulting from heating the mixes to 70 and 80 degrees C and cooling to room temperature. Thermorheological studies showed a maximum in viscosity for the xanthan gum gels at approximately 45 degrees C; this maximum became less pronounced as the concentration of XG decreased. High sensitivity differential scanning calorimetry indicated that XG undergoes two transitions at approximately 30 and 80 degrees C on heating, but on cycling a single transition is seen at approximately 74 degrees C. It was also noted that the transitions were diminished or were absent in the presence of LBG.