Radicicol suppresses expression of inducible nitric-oxide synthase by blocking p38 kinase and nuclear factor-kappaB/Rel in lipopolysaccharide-stimulated macrophages

We show that radicicol, a fungal antibiotic, produces a marked inhibition of p38 kinase, nuclear factor-kappaB/Rel (NF-kappaB/Rel), and inducible nitric-oxide synthase (iNOS) transcription by the macrophage line RAW 264.7 in response to lipopolysaccharide (LPS). Treatment of RAW 264.7 with radicicol inhibited LPS-stimulated p38 kinase phosphorylation in a dose-related manner. iNOS transcription, which is regulated in part by the NF-kappaB/Rel family of transcription factors, has been shown to be under the control of the p38 kinase signaling cascade. Our data also show that the p38 kinase pathway is specifically involved in LPS-induced NF-kappaB/Rel activation and iNOS expression because NF-kappaB/Rel DNA binding and iNOS mRNA production in the presence of a specific inhibitor of p38 kinase, SB203580, were dramatically diminished. In contrast, PD98059, a specific inhibitor of mitogen-activated protein kinase/extracellular signal-regulated protein kinase kinase 1 had no effect on NF-kappaB/Rel activation and iNOS expression. LPS-induced loss of inhibitory proteins IkappaB-alpha and IkappaB-beta and translocation of p65, c-Rel, and p50 was inhibited by radicicol. Collectively, this series of experiments indicates that radicicol inhibits iNOS gene expression by blocking p38 kinase signaling. Due to the critical role that NO release plays in mediating inflammatory responses, the inhibitory effects of radicicol on iNOS suggest that this potent antifungal agent may represent a useful anti-inflammatory agent.

Genetic analysis of the role of Pol II holoenzyme components in repression by the Cyc8-Tup1 corepressor in yeast

The Cyc8-Tup1 corepressor complex is targeted to promoters by pathway-specific DNA-binding repressors, thereby inhibiting the transcription of specific classes of genes. Genetic screens have identified mutations in a variety of Pol II holoenzyme components (Srb8, Srb9, Srb10, Srb11, Sin4, Rgr1, Rox3, and Hrs1) and in the N-terminal tails of histones H3 and H4 that weaken repression by Cyc8-Tup1. Here, we analyze the effect of individual and multiple mutations in many of these components on transcriptional repression of natural promoters that are regulated by Cyc8-Tup1. In all cases tested, individual mutations have a very modest effect on SUC2 RNA levels and no detectable effect on levels of ANB1, MFA2, and RNR2. Furthermore, multiple mutations within the Srb components, between Srbs and Sin4, and between Srbs and histone tails affect Cyc8-Tup1 repression to the same modest extent as the individual mutations. These results argue that the weak effects of the various mutations on repression by Cyc8-Tup1 are not due to redundancy among components of the Pol II machinery, and they argue against a simple redundancy between the holoenzyme and chromatin pathways. In addition, phenotypic analysis indicates that, although Srbs8-11 are indistinguishable with respect to Cyc8-Tup1 repression, the individual Srbs are functionally distinct in other respects. Genetic interactions among srb mutations imply that a balance between the activities of Srb8 + Srb10 and Srb11 is important for normal cell growth.

Paclitaxel causes mouse splenic lymphocytes to a state hyporesponsive to lipopolysaccharide stimulation

Multiple immune system actions have been ascribed to paclitaxel (taxol), a novel anticancer drug, including the capacity to induce macrophage antitumor cytotoxic molecule production. In the present studies, we demonstrated that paclitaxel produced a selective inhibition of lipopolysaccharide (LPS)-induced B cell proliferation. Similarly, in vitro polyclonal antibody-forming cell responses also were found to be inhibited by paclitaxel. Conversely, paclitaxel exhibited no inhibitory effects on concanavalin A (Con A)-induced T cell proliferation. To study the pathway leading to paclitaxel-induced immunosuppression, we analyzed Raf-1/ERK and JNK/p38 MAPK pathways, both of which have been reported to be involved in LPS signaling. Our results indicate that taxol treatment inhibits Raf-1 kinase activation while having no effect on ERK activation suggesting that ERK activation is distinct from upstream Raf-1 kinase in taxol-induced immunomodulation. Furthermore, paclitaxel pretreatment caused down-regulation of stress-activated MAPKs, JNK and p38 MAPK in lipopolysaccharide (LPS)-stimulated mouse splenic lymphocytes, demonstrating that spleen cells are induced to a state hyporesponsive to LPS stimulation by pre-exposing them to paclitaxel. Taken together, these results suggest that down-regulation of JNK/p38 MAP kinase may contribute to paclitaxel-induced immunosuppression in mouse splenic lymphocytes.

Association of an ERCC1 polymorphism with adult-onset glioma

Gliomas include several histologically distinct types of tumors whose molecular profiles suggest different etiologies. Because the ERCC1 protein is essential for nucleotide excision repair and influences genomic instability, polymorphisms in ERCC1 may play a role in human tumors. We determined the presence of the A versus C polymorphism at nucleotide 8092 of ERCC1 using a single-strand conformational polymorphism assay and DNA sequencing in adults with glioma and controls from a population-based study. Among 318 alleles from 159 controls, 27% (86) were A and 73% were C. Prevalences of the CC genotype were 51% (81 of 159), 48% (30 of 62), 63% (20 of 32), and 82% (23 of 28) for controls and subjects with glioblastoma multiforme, astrocytoma, and oligoastrocytoma, respectively (Fisher's exact P = 0.009). The age-adjusted odds ratio for genotype CC in all cases versus controls was 1.4 (95% confidence interval, 0.9-2.3), whereas that for subjects with oligoastrocytoma versus controls was 4.6 (95% confidence interval, 1.6-13.2). The median age at diagnosis was 46 years for glioma patients with the CC genotype compared with 54 years for patients with the AA or AC genotype (P = 0.04). This is the first study to report a significant association of a polymorphism in ERCC1 with the risk of brain tumors. This A/C polymorphism, which may affect mRNA stability for ERCC1, also results in an amino acid substitution of lysine to glutamine in a recently described nucleolar protein (ASE-1) and T-cell receptor complex subunit CD3epsilon-associated signal transducer (CAST). This finding, if confirmed in other series, may provide a foundation on which to study novel mechanisms of carcinogenesis in subsets of glioma.

Requirement of mature dendritic cells for efficient activation of influenza A-specific memory CD8+ T cells

It is critical to identify the developmental stage of dendritic cells (DCs) that is most efficient at inducing CD8+ T cell responses. Immature DCs can be generated from monocytes with GM-CSF and IL-4, while maturation is accomplished by the addition of stimuli such as monocyte-conditioned medium, CD40 ligand, and LPS. We evaluated the ability of human monocytes and immature and mature DCs to induce CD8+ effector responses to influenza virus Ags from resting memory cells. We studied replicating virus, nonreplicating virus, and the HLA-A*0201-restricted influenza matrix protein peptide. Sensitive and quantitative assays were used to measure influenza A-specific immune responses, including MHC class I tetramer binding assays, enzyme-linked immunospot assays for IFN-gamma production, and generation of cytotoxic T cells. Mature DCs were demonstrated to be superior to immature DC in eliciting IFN-gamma production from CD8+ effector cells. Furthermore, only mature DCs, not immature DCs, could expand and differentiate CTL precursors into cytotoxic effector cells over 7 days. An exception to this was immature DCs infected with live influenza virus, because of the virus's known maturation effect. Finally, mature DCs pulsed with matrix peptide induced CTLs from highly purified CD8+ T cells without requiring CD4+ T cell help. These differences between DC stages were independent of Ag concentrations or the number of immature DCs. In contrast to DCs, monocytes were markedly inferior or completely ineffective stimulators of T cell immunity. Our data with several qualitatively different assays of the memory CD8+ T cell response suggest that mature cells should be considered as immunotherapeutic adjuvants for Ag delivery.

Construction and characterization of murine cytomegaloviruses that contain transposon insertions at open reading frames m09 and M83

A transposon derived from Escherichia coli Tn3 was introduced into the genome of murine cytomegalovirus (MCMV) to generate a pool of viral mutants, including two recombinant viruses that contained the transposon sequence within open reading frames m09 and M83. Our studies provide the first direct evidence to suggest that m09 is not essential for viral replication in mouse NIH 3T3 cells. Studies in cultured cells and in both BALB/c-Byj and CB17 severe combined immunodeficient (SCID) mice indicated that the transposon insertion is stable during viral propagation both in vitro and in vivo. Moreover, the virus that contained the insertion mutation in m09 exhibited a titer similar to that of the wild-type virus in the salivary glands, lungs, livers, spleens, and kidneys of both the BALB/c and SCID mice and was as virulent as the wild-type virus in killing the SCID mice when these animals were intraperitoneally infected with these viruses. These results suggest that m09 is dispensable for viral growth in these organs and that the presence of the transposon sequence in the viral genome does not significantly affect viral replication in vivo. In contrast, the virus that contained the insertion mutation in M83 exhibited a titer of at least 60-fold lower than that of the wild-type virus in the organs of the SCID mice and was attenuated in killing the SCID mice. These results demonstrate the utility of using the Tn3-based system as a mutagenesis approach for studying the function of MCMV genes in both immunocompetent and immunodeficient animals.

Peripherally administered antibodies against amyloid beta-peptide enter the central nervous system and reduce pathology in a mouse model of Alzheimer disease

One hallmark of Alzheimer disease is the accumulation of amyloid beta-peptide in the brain and its deposition as plaques. Mice transgenic for an amyloid beta precursor protein (APP) mini-gene driven by a platelet-derived (PD) growth factor promoter (PDAPP mice), which overexpress one of the disease-linked mutant forms of the human amyloid precursor protein, show many of the pathological features of Alzheimer disease, including extensive deposition of extracellular amyloid plaques, astrocytosis and neuritic dystrophy. Active immunization of PDAPP mice with human amyloid beta-peptide reduces plaque burden and its associated pathologies. Several hypotheses have been proposed regarding the mechanism of this response. Here we report that peripheral administration of antibodies against amyloid beta-peptide, was sufficient to reduce amyloid burden. Despite their relatively modest serum levels, the passively administered antibodies were able to enter the central nervous system, decorate plaques and induce clearance of preexisting amyloid. When examined in an ex vivo assay with sections of PDAPP or Alzheimer disease brain tissue, antibodies against amyloid beta-peptide triggered microglial cells to clear plaques through Fc receptor-mediated phagocytosis and subsequent peptide degradation. These results indicate that antibodies can cross the blood-brain barrier to act directly in the central nervous system and should be considered as a therapeutic approach for the treatment of Alzheimer disease and other neurological disorders.

Hydrogen peroxide inhibits the immune response to lipopolysaccharide by attenuating signaling through c-Jun N-terminal kinase and p38 associated with protein kinase C

This study examined the immunomodulatory effects of hydrogen peroxide (H(2)O(2)) in B6C3F1 mouse splenic lymphocytes. H(2)O(2) produced a marked and dose-related inhibition of both lipopolysaccharide (LPS)-induced B-cell proliferation and concanavalin A (Con A)-induced T-cell proliferation. Unexpectedly, little effect was observed with H(2)O(2) on the antibody-forming cell (AFC) response to the polyclonal B-cell activator, LPS. It was also observed that H(2)O(2) did not have any detectable effect on forskolin-stimulated adenylate cyclase, indicating that cyclic AMP (cAMP) is not a mediator of H(2)O(2)-induced suppression of the immune response. Rather, LPS-induced activation of protein kinase C (PKC) was completely inhibited when cells were pretreated with H(2)O(2) for 18 h, although PKC activity was increased approximately twofold following treatment with H(2)O(2) for 10 min. In addition, H(2)O(2) pretreatment blocked the phosphorylation of two stress-activated mitogen-activated protein kinases (MAPKs), c-Jun N-terminal kinase (JNK) and p38 by LPS in a concentration-dependent fashion. Therefore, these data suggest that H(2)O(2) suppresses immune response through the desensitization of PKC, which subsequently results in inhibition of JNK and p38.

Dexamethasone inhibits IL-1 beta gene expression in LPS-stimulated RAW 264.7 cells by blocking NF-kappa B/Rel and AP-1 activation

In the present study, the mechanism by which dexamethasone (DEX) inhibited IL-1beta gene expression in bacterial lipopolysaccharide (LPS)-activated RAW 264.7 cells was investigated. The decrease in LPS-induced IL-1beta mRNA expression was demonstrated by quantitative reverse transcription polymerase chain reaction (RT-PCR). Since the promoter in IL-1beta gene contains binding motifs for NF-kappaB/Rel, AP-1, NF-IL6, and CREB/ATF, which appear to be important in LPS-mediated IL-1beta induction, the effects of DEX on the activation of these transcription factors were examined. Treatment of DEX to RAW 264.7 cells induced a dose-related inhibition of NF-kappaB/Rel and AP-1 in chloramphenicol acetyltransferase activity, while neither NF-IL6 nor CREB/ATF activation was affected by DEX. Treatment of RAW 264.7 cells with DEX inhibited DNA binding of NF-kappaB/Rel and AP-1 proteins to their cognate DNA sites as measured by electrophoretic mobility shift assay (EMSA). DEX treatment caused a significant reduction in nuclear c-rel, p65, and p50 protein contents, and these decreases were paralleled by the accumulation of cytoplasmic c-rel, p65, and p50. DEX treatment of RAW 264.7 cells did not inhibit the nuclear translocation of c-jun and c-fos. We found that the inhibition of IL-1beta production by DEX is not related to p38, which is important in the IL-1beta induction. These results suggest that DEX may inhibit IL-1beta gene expression by a mechanism involving the blocking of LPS-induced NF-kappaB/Rel and AP-1 activation.

A safer plasma supply from remunerated donors--"The Immuno/Community Bio-Resources experiment"

With the goal of increasing the safety of plasma used in the manufacture of therapeutic products, Immuno and its subsidiary Community Bio-Resources (now a division of Baxter Healthcare Corporation), have developed a comprehensive plasma quality programme. This programme includes four main safety initiatives: a plasma centre location/appearance programme, a Qualified Donor programme, an Inventory Hold, and the PCR testing of plasma pools. Many of these initiatives have been adopted in part by the plasma collection and fractionation industry. Using a statistical model that takes into consideration the unique donation characteristics of remunerated plasma donors, combined with 1998 CBR virus reactive rates, an estimated residual likelihood of an undetected donation entering a plasma pool was determined. These estimates, for each million donations, were 0, 1.64, and 4.68 donations for HIV, HBV, and HCV, respectively, and were far below those previously reported for remunerated or volunteer donations. These estimates were confirmed by subsequent PCR testing, which allowed for the additional removal of positive units before manufacture. The low virus load of this plasma supply, combined with increasingly effective virus removal and inactivation procedures, has resulted in the safest ever supply of plasma derivatives.

Characterization of the mouse lanosterol 14alpha-demethylase (CYP51), a new member of the evolutionarily most conserved cytochrome P450 family

Genes encoding sterol 14alpha-demethylases in eukaryotes and in Mycobacterium belong to the CYP51 family which is evolutionary the most conserved gene family within the cytochrome P450 superfamily. We have characterized a new member of this family, the mouse lanosterol 14alpha-demethylase, with the aim to study the in vivo role of this gene in spermatogenesis in mammals. The amino acid sequence of mouse Cyp51 is 96% identical to rat and 91% to human. Comparison of all known CYP51 proteins by the neighbor-joining method suggests that fungal and animal CYP51 genes arose from a common ancestral gene (98.3% probability) and interestingly, that plant and bacterial CYP51 genes share a common progenitor (88.8% probability). This suggests that the first CYP51 gene may have arisen in eukaryotes and has been transferred horizontally from plants to Mycobacterium. The mouse CYP51 gene is approximately 17-kb long and contains 10 exons. Transcription starts at several locations within the CpG island, which is characteristic for the TATA-less housekeeping genes. The mouse 5'-untranslated region (800 bp) contains putative cAMP-responsive elements (CRE), sterol regulatory elements (SRE) and GC-boxes at positions similar to human and rat, suggesting an evolutionary conserved mechanism of CYP51 transcriptional regulation in mammals. The mouse Cyp51 gene resides on chromosome 5, region A2, close to the centromere. No signals outside this region were detected as well as no evidence of processed pseudogenes using long PCR was found. This indicates that the mouse genome most likely lacks CYP51 processed pseudogenes.

Effects of enzyme inducers or inhibitors on the pharmacokinetics of intravenous parathion in rats

In order to find what form of hepatic cytochrome P450 (CYP) is involved in the metabolism of parathion to form paraoxon, rats were pretreated with the enzyme inhibitors, such as SKF 525-A and ketoconazole or enzyme inducers, such as dexamethasone, isoniazid, phenobarbital, and 3-methylcholanthrene. Parathion, 3 mg/kg, was infused in 1 min via the jugular vein. In rats pretreated with SKF 525-A or ketoconazole, nonspecific CYP inhibitors, the area under the plasma concentration-time curve from time zero to time infinity (AUC) and total body clearance (Cl) of parathion were significantly greater and slower, respectively, than those in respective control rats, suggesting that parathion was metabolized by CYPs. In rats pretreated with dexamethasone (CYP3A23 inducer), the AUC was significantly smaller (41.5 compared with 52.5 microg min/mL), Cl was significantly faster (72.2 compared with 57.1 mL/min/kg), and the amounts and/or tissue-to-plasma ratios of parathion was significantly (or tended to be) smaller than those in control rats. However, the pharmacokinetic parameters of parathion were not significantly different after pretreatment with other enzyme inducers compared with respective control rats. The above data suggested that parathion was metabolized to paraoxon by dexamethasone-inducible CYP3A23, the induction of which was confirmed by Western blot analysis. This was supported by in vitro intrinsic clearance (Cl(int)) of parathion to form paraoxon in hepatic microsomal fraction; the Cl(int) in rats pretreated with dexamethasone was significantly faster (0.0900 compared with 0.0290 mL/min/mg protein) than that in control rats.

Analysis of chromosome abnormalities in sperm and embryos from two 45,XY,t(13;14)(q10;q10) carriers

Robertsonian translocation t(13q14q) is studied in sperm and embryos of two couples undergoing preimplantation genetic diagnosis (PGD) in which both males are carriers of the translocation. It is already known that the chances of achieving pregnancy for a translocation carrier are directly linked to the number of normal or balanced embryos available for replacement. In our work it was found that the frequency of balanced spermatozoa was almost identical in both patients (74 and 77%), and after PGD, the frequencies of abnormal embryos caused by the translocation were also similar. Sperm chromosome analysis in translocation carriers can provide a reasonable basis for estimating a baseline of chromosome abnormalities to be found in embryos during an assisted reproductive cycle. However, individual factors not linked to the translocation can also produce other chromosome abnormalities (mosaicism, haploidy, polyploidy) and may compromise the chances of achieving a viable pregnancy.

Experience with a higher impedance, fixed helix, steroid-eluting pacing lead. The SWEET PICOTIP Rx Study Group

A higher impedance, steroid-eluting pacing lead was studied in a multicenter trial. A total of 132 leads were implanted in 61 patients and the electrical characteristics were compared with historical controls. The study lead had a lower pacing threshold at 3 months, 0.72 +/- 0.33 versus 1.29 +/- 0.82 in the atrium and 0.71 +/- 0.25 versus 1.52 +/- 0.52 in the ventricle (P < 0.01 for both). Impedance was significantly higher in the study lead, 923 +/- 133 versus 719 +/- 109 in the atrium and 980 +/- 235 versus 664 +/- 104 in the ventricle (P < 0.01 for both). Sensing was similar for both leads. The study lead's higher impedance values and low pacing thresholds combine to reduce pacing system energy requirements.

Development of a web-based picture archiving and communication system using satellite data communication

Using the JAVA language we have developed a Web-based picture archiving and communication system (PACS) which allows a remote hospital to access medical images. An asymmetric satellite data communication system (ASDCS) provided a receive-only link for data delivery and a conventional terrestrial link (which could be the conventional telephone network) allowed data transmission. The satellite communication link was 10-30 times faster than the conventional terrestrial link. To increase image transmission speeds over the Internet connection, JPEG and wavelet compression methods were used. The resulting images were evaluated quantitatively by measuring the peak signal:noise ratio and qualitatively by radiologists. Compression ratios of 10:1 or less were deemed acceptable for diagnostic purposes. The system appears to be suitable for teleradiology and telemedicine.

A fiber-optic microarray biosensor using aptamers as receptors

A fiber-optic biosensor using an aptamer receptor has been developed for the measurement of thrombin. An antithrombin DNA aptamer was immobilized on the surface of silica microspheres, and these aptamer beads were distributed in microwells on the distal tip of an imaging fiber. A different oligonucleotide bead type prepared using the same method as the aptamer beads was also included in the microwells to measure the degree of nonspecific binding. The imaging fiber was coupled to a modified epifluorescence microscope system, and the distal end of the fiber was incubated with a fluorescein-labeled thrombin (F-thrombin) solution. Nonlabeled thrombin could be detected using a competitive binding assay with F-thrombin. The aptamer beads selectively bound to the target and could be reused without any sensitivity change. The fiber-optic microarray system has a detection limit of 1 nM for nonlabeled thrombin, and each test can be performed in ca. 15 min including the regeneration time.

Phospholipid:diacylglycerol acyltransferase: an enzyme that catalyzes the acyl-CoA-independent formation of triacylglycerol in yeast and plants

Triacylglycerol (TAG) is known to be synthesized in a reaction that uses acyl-CoA as acyl donor and diacylglycerol (DAG) as acceptor, and which is catalyzed by the enzyme acyl-CoA:diacylglycerol acyltransferase. We have found that some plants and yeast also have an acyl-CoA-independent mechanism for TAG synthesis, which uses phospholipids as acyl donors and DAG as acceptor. This reaction is catalyzed by an enzyme that we call phospholipid:diacylglycerol acyltransferase, or PDAT. PDAT was characterized in microsomal preparations from three different oil seeds: sunflower, castor bean, and Crepis palaestina. We found that the specificity of the enzyme for the acyl group in the phospholipid varies between these species. Thus, C. palaestina PDAT preferentially incorporates vernoloyl groups into TAG, whereas PDAT from castor bean incorporates both ricinoleoyl and vernoloyl groups. We further found that PDAT activity also is present in yeast microsomes. The substrate specificity of this PDAT depends on the head group of the acyl donor, the acyl group transferred, and the acyl chains of the acceptor DAG. The gene encoding the enzyme was identified. The encoded PDAT protein is related to lecithin:cholesterol acyltransferase, which catalyzes the acyl-CoA-independent synthesis of cholesterol esters. However, budding yeast PDAT and its relatives in fission yeast and Arabidopsis form a distinct branch within this protein superfamily, indicating that a separate PDAT enzyme arose at an early point in evolution.

Platelet surface P-selectin molecules increased after exposing platelet to a high shear flow

BACKGROUND

P-selectin is known to play a crucial role in leucocyte recruitment at sites of vascular injury. Although platelet surface expression of P-selectin molecules are well known to occur after platelet stimulation by chemical agonists such as alpha-thrombin, it is still uncertain whether P-selectin expression occurs in the process of the more physiological platelet activation pathway mediated by interaction between von Willebrand factor (vWF) and platelet receptor proteins, including glycoprotein (GP) Ibalpha and GP IIb/IIIa, occurring under high shear rates generated by blood flow.

METHODS

We have developed a method to detect P-selectin molecules expressed on platelet surface with flow-cytometer and monoclonal antibody, which can bind exclusively to P-selectin (WGA1), directly conjugated with fluorescein isothiocynate. This method allowed us to measure platelet surface P-selectin molecules semiquantitatively.

RESULTS

We demonstrated that a significant increase in platelet surface P-selectin molecules occur after exposing platelets to a relatively high shear rate of 10,800 s(-1). We have also demonstrated that shear-induced surface expression of P-selectin as well as microparticle release from platelets depended at least on the interaction between von Willebrand factor and glycoprotein Ibalpha, a platelet surface receptor for the former.

CONCLUSIONS

Shear-induced von Willebrand-mediated surface expression of P-selectin may play a role in leucocyte recruitment in platelet thrombi at vascular injury sites.

A bifunctional delta-fatty acyl acetylenase/desaturase from the moss Ceratodon purpureus. A new member of the cytochrome b5 superfamily

Many plant genes have been cloned that encode regioselective desaturases catalyzing the formation of cis-unsaturated fatty acids. However, very few genes have been cloned that encode enzymes catalyzing the formation of the functional groups found in unusual fatty acids (e.g. hydroxy, epoxy or acetylenic fatty acids). Here, we describe the characterization of an acetylenase from the moss Ceratodon purpureus with a regioselectivity differing from the previously described Delta12-acetylenase. The gene encoding this protein, together with a Delta6-desaturase, was cloned by a PCR-based approach with primers derived from conserved regions in Delta5-, Delta6-fatty-acid desaturases and Delta8-sphingolipid desaturases. The proteins that are encoded by the two cloned cDNAs are likely to consist of a N-terminal extension of unknown function, a cytochrome b5-domain, and a C-terminal domain that is similar to acyl lipid desaturases with characteristic histidine boxes. The proteins were highly homologous in sequence to the Delta6-desaturase from the moss Physcomitrella patens. When these two cDNAs were expressed in Saccharomyces cerevisiae, both transgenic yeast cultures desaturated Delta9-unsaturated C16- and C18-fatty acids by inserting an additional Delta6cis-double bond. One of these transgenic yeast clones was also able to introduce a Delta6-triple bond into gamma-linolenic and stearidonic acid. This resulted in the formation of 9,12,15-(Z,Z,Z)-octadecatrien-6-ynoic acid, the main fatty acid found in C. pupureus. These results demonstrate that the Delta6-acetylenase from C. pupureus is a bifunctional enzyme, which can introduce a Delta6cis-double bond into 9,12,(15)-C18-polyenoic acids as well as converting a Delta6cis-double bond to a Delta6-triple bond.

How well does chart abstraction measure quality? A prospective comparison of standardized patients with the medical record

PURPOSE

Despite widespread reliance on chart abstraction for quality measurement, concerns persist about its reliability and validity. We prospectively evaluated the validity of chart abstraction by directly comparing it with the gold standard of reports by standardized patients.

SUBJECTS AND METHODS

Twenty randomly selected general internal medicine residents and attending faculty physicians at the primary care clinics of two Veterans Affairs Medical Centers blindly evaluated and treated actor-patients (standardized patients) who had one of four common diseases: diabetes, chronic obstructive pulmonary disease, coronary artery disease, or low back pain. Charts from the visits were abstracted using explicit quality criteria; standardized patients completed a checklist containing the same criteria. For each physician, quality was measured for two different cases of the four conditions (a total of 160 physician-patient encounters). We compared chart abstraction with standardized-patient reports for four aspects of the encounter: taking the history, examining the patient, making the diagnosis, and prescribing appropriate treatment. The sensitivity and specificity of chart abstraction were calculated.

RESULTS

The mean (+/- SD) chart abstraction score was 54% +/- 9%, substantially less than the mean score on the standardized-patient checklist of 68% +/- 9% (P <0.001). This finding was similar for all four conditions and at both sites. "False positives"-chart-recorded necessary care actions not reported by the standardized patients-resulted in a specificity of only 81%. The overall sensitivity of chart abstraction for necessary care was only 70%.

CONCLUSIONS

Chart abstraction underestimates the quality of care for common outpatient general medical conditions when compared with standardized-patient reports. The medical record is neither sensitive nor specific. Quality measurements derived from chart abstraction may have important shortcomings, particularly as the basis for drawing policy conclusions or making management decisions.

Changes in nasal leukocytes and epithelial cells associated with topical beclomethasone treatment

BACKGROUND

We had previously observed that changes in nasal cytology were associated with specific clinical patterns in cross-sectional studies of allergy clinic patients. In the present study, we sought to determine whether specific cytologic changes occurred with antiinflammatory therapy in a controlled setting in a prospective manner.

OBJECTIVE

To examine changes in nasal leukocytes and epithelial cells associated with topical beclomethasone treatment in allergic rhinitis patients. Specifically we tested the hypothesis that number of nasal leukocytes relative to epithelial cell numbers are altered by topical beclomethasone treatment.

METHODS

Adult volunteers (n=26) with symptoms consistent with allergic rhinitis and positive aeroallergen skin tests were enrolled for treatment with either beclomethasone or placebo nasal spray. Sprays were allocated in a double-blind manner and were prescribed to be administered over a 2-week period. Baseline quality of life, nasal cytograms, and mucosal physical appearance scores were obtained at baseline and at the end of the treatment period. Changes in various nasal leukocytes and epithelial cell types were analyzed for association with active treatment using bivariate and multivariate analysis.

RESULTS

Total leukocytes showed greater decreases with beclomethasone treatment than with placebo. Total epithelial cells on the other hand showed an increase with active treatment compared with placebo treatment. In multivariate analysis, the changes in both total leukocytes and total epithelial cells showed independent associations with beclomethasone treatment. Combining these two variables into a single leukocyte per epithelial ratio resulted in variable with values showing a significant decreases associated with beclomethasone treatment compared with placebo treatment (P = .03).

CONCLUSIONS

The administration of topical corticosteroids results in decreases in total leukocytes and this decrease is of enhanced significance when adjusted for the quantities of associated epithelial cells. Further investigation relating to the quantities of total nasal leukocytes in inflammatory nasal diseases may be helpful in gauging disease activity and monitoring treatment modalities.

Short-term effects of lumbar posteroanterior mobilization in individuals with low-back pain

OBJECTIVE

To establish the short-term effects of lumbar posteroanterior mobilization in patients with low-back pain, compared with a control intervention.

DESIGN

Self-controlled cross-over design.

MAIN OUTCOME MEASURES

The force-displacement characteristics of the spine in response to the application of a posteroanterior force, lumbar flexion, and extension range of movement; pain during flexion, extension, and on worst movement; pain on posteroanterior loading; and overall pain relief.

PATIENTS

Twenty-six patients with nonspecific low-back pain who experienced pain on flexion or extension and whose pain settled quickly after provocation, from a physiotherapy clinic and university campus.

METHODS

Patients received posteroanterior mobilization and a control intervention in an order that was randomly allocated. The magnitude of force in treatment dose was selected by the treating physiotherapist. An observer who was blinded to the order of interventions performed all measurements. Outcome measures were recorded before and after each intervention, and change scores were calculated to quantify the effect of the intervention.

RESULTS

No significant differences were found between the mobilization and control interventions in relation to posteroanterior response or range of movement. The score for pain on worst movement showed significantly greater improvement for the mobilization than for the control procedure.

CONCLUSIONS

Lumbar posteroanterior mobilization was not observed to produce any objectively measurable change in the mechanical behavior of the lumbar spine of patients with low-back pain. Improvement in some pain variables was observed in comparison with a control procedure, but this may be due to a placebo effect.