Does reporting of plain chest radiographs affect the immediate management of patients admitted to a medical assessment unit?

AIM

The purpose of our study was to investigate whether reporting of plain chest radiographs affects immediate management of patients admitted to a medical assessment unit.

MATERIALS AND METHODS

During a 3 month period we prospectively evaluated 200 patients who had a plain chest radiograph on admission. After the post on-call ward round, an independent medical specialist registrar reviewed the notes, retrieving relevant clinical details. The plain chest films were reported independently by a trainee radiologist and consultant, reaching a consensus report.

RESULTS

There was 93% agreement between trainee and consultant radiologists (95% CI=89-96%). Seventy percent had documented reports by the on-call medical team. There was disagreement between radiology and medical reports in 49% of reported films (95% CI=40-57%). The radiologist's report led to a direct change in the immediate management of 22 patients (11%).

CONCLUSION

Only 70% of films had documented reports in the clinical notes despite this being a legal requirement. Radiology reporting does cause a direct change in patient management. Chest radiographs of patients admitted to a medical admissions unit should be reported by a radiologist with the minimum of delay.

Halophilic adaptation of protein-DNA interactions

Pyrococcus woesei ( Pw ) is an archaeal organism adapted to living in conditions of elevated salt and temperature. Thermodynamic data reveal that the interaction between the TATA-box-binding protein (TBP) from this organism and DNA has an entirely different character to the same interaction in mesophilic counterparts. In the case of the Pw TBP, the affinity of its interaction with DNA increases with increasing salt concentration. The opposite effect is observed in all known mesophilic protein-DNA interactions. The halophilic behaviour can be attributed to sequestration of cations into the protein-DNA complex. By mutating residues in the Pw TBP DNA-binding site, potential sites of cation interaction can be removed. These mutations have a significant effect on the binding characteristics, and the halophilic nature of the Pw TBP-DNA interaction can be reversed, and made to resemble that of a mesophile, in just three mutations. The genes of functionally homologous proteins in organisms existing in different environments show that adaptation is most often accompanied by mutation of an existing protein. However, the importance of any individual residue to a phenotypic characteristic is usually difficult to assess amongst the multitude of changes that occur over evolutionary time. Since the halophilic nature of this protein can be attributed to only three mutations, this reveals that the important phenotype of halophilicity could be rapidly acquired in evolutionary time.

Extensive and preferential Fas/Fas ligand-dependent death of gammadelta T cells following infection with Listeria monocytogenes

In the spleens of mice infected intraperitoneally with the bacterium Listeria monocytogenes, both alphabeta and gammadelta T cells became rapidly activated, followed by a massive apoptotic death response predominantly within the gammadelta population. The death response involved two major splenic gammadelta T-cell subsets and was Fas/Fas ligand (Fas-L)-dependent. Among T cells isolated from the Listeria-infected spleen, Fas-L was almost exclusively expressed in gammadelta T cells. gammadelta T cells coexpressed Fas and Fas-L, suggesting activation-induced suicide as a mechanism of their death. In vivo treatment with an antibody specific for CD3epsilon induced activation, preferential Fas-L expression and apoptosis of gammadelta T cells, resembling the response pattern in listeriosis, whereas antibodies specific for T-cell receptor-beta (TCR-beta) or TCR-delta did not, suggesting that the complete response seen in listeriosis requires both gammadelta TCR engagement and additional stimuli. L. monocytogenes causes early nonspecific, Fas-independent lymphocyte death in heavily infected tissues. In contrast, the death response described here is selective, Fas-dependent and triggered at low local levels of bacteria, suggesting that it is controlled by interactions with other infection-activated host cells, and perhaps part of a regulatory circuit specifically curtailing gammadelta T cells.

MAOB intron 13 and COMT codon 158 polymorphisms, cigarette smoking, and the risk of PD

BACKGROUND

A polymorphism (G to A transition) in intron 13 of the mitochondrial enzyme monoamine oxidase B (MAOB) gene may modify, alone or by interacting with the catechol-O-methyltransferase (COMT(LL)) genotype (low enzymatic activity), the risk of idiopathic PD. Also, the association between never smoking and PD risk may be present only in people with the MAOB G allele.

METHODS

The authors studied two ongoing prospective cohorts-the Nurses' Health Study (121,700 women aged 30 to 55 in 1976) and the Health Professionals' Follow-up Study (51,529 men aged 40 to 75 in 1986). They identified new PD cases through 1996, selected random control subjects matched on age and study cohort, and obtained DNA samples from blood or buccal smears from 85% of the eligible cases and 84% of the control subjects. They included genotypes from 214 cases and 449 control subjects, all Caucasian.

RESULTS

The odds ratio of PD was 1.2 (95% CI 0.9, 1.7) for MAOB genotypes G/GG/GA compared with genotypes A/AA, and 1.1 (0.7, 1.8) for COMT genotypes LL compared with HH. The odds ratio (95% CI) was 1.7 (0.7, 3.9) for those with MAOB G/GG and COMT(LL) genotypes compared with those with MAOB A/AA and COMT(HH). There was a strong association between never smoking and PD risk in all groups defined by MAOB and COMT genotypes.

CONCLUSION

The findings do not support a major role of the MAOB intron 13 polymorphism in the development of PD, either by itself or by interacting with smoking.

Specific DNA recognition by the type II restriction endonuclease MunI: the effect of pH

To investigate the effect of pH on sequence-specific binding, a thermodynamic characterization of the interaction of the protein MunI with a specific, and a nonspecific, oligonucleotide was performed. MunI is a type II restriction endonuclease which is able to bind specifically, but loses its enzymatic activity in the absence of magnesium ions. Comparison of the specific and nonspecific interactions at 10 and 25 degrees C shows that the latter is accompanied by a small change in enthalpy, and a negligible change in constant pressure heat capacity. On going through the pH range 5.75-9.0 at 25 degrees C, the affinity of specific complex formation is reduced by 20-fold. The interaction is accompanied by the protonation of groups assumed to be on the protein. Based on the simplest model that will fit the data, two distinct protonation events are observed. At low pH, two groups per protein molecule undergo protonation with a pK(a) of 6.0 and 6.9 in the free and bound forms, respectively. At high pH, a further independent protonation occurs involving two groups with pK(a) values of 8.9 and approximately 10.7 in the free and bound forms, respectively. The change in heat capacity ranges from -2.7 to -1.7 kJ mol(-1) K(-1) in going from pH 6.5 to 8.5. This range of variation of change in heat capacity can be accounted for by the effects of protonation of the interacting molecules. The change in heat capacity, calculated from surface area burial using a previously established relationship (1.15 kJ mol(-1) K(-1)), does not correlate well with the experimentally determined values.

Evaluation of the Mycobacterium bovis restriction fragment length polymorphism probe pUCD, in combination with the direct repeat probe, for molecular typing of Mycobacterium tuberculosis strains in Ireland

A mycobacterial restriction fragment length polymorphism probe, pUCD, has recently been described which represents an effective tool for the strain typing of Mycobacterium bovis. The present study evaluated this probe, in combination with the direct repeat probe (DR), for the molecular typing of 90 strains of Mycobacterium tuberculosis from 87 patients, looking at a group (62 isolates) of nonselected samples to assess pUCD combined with DR as a general tool and a subset of 32 isolates with a common specific IS6110 strain type in Ireland. Within the group of 62 isolates, pUCD-DR identified 42 strains and was comparable to both IS6110 (41 strains) and polymorphic guanine-cytosine-rich sequence (PGRS) (37 strains) analysis. pUCD-DR was found to be comparable to IS6110 and PGRS in identifying four separate clusters of isolates which were confirmed to be clinically related. pUCD-DR divided the common IS6110 isolates into six distinct types and was comparable to PGRS (seven strain types). The usefulness of this probe as an epidemiological tool is discussed.

Randomized controlled trial of motivational interviewing, cognitive behavior therapy, and family intervention for patients with comorbid schizophrenia and substance use disorders

OBJECTIVE

Comorbidity of substance abuse disorders with schizophrenia is associated with a greater risk for serious illness complications and poorer outcome. Methodologically sound studies investigating treatment approaches for patients with these disorders are rare, although recommendations for integrated and comprehensive treatment programs abound. This study investigates the relative benefit of adding an integrated psychological and psychosocial treatment program to routine psychiatric care for patients with schizophrenia and substance use disorders.

METHOD

The authors conducted a randomized, single-blind controlled comparison of routine care with a program of routine care integrated with motivational interviewing, cognitive behavior therapy, and family or caregiver intervention.

RESULTS

The integrated treatment program resulted in significantly greater improvement in patients' general functioning than routine care alone at the end of treatment and 12 months after the beginning of the study. Other benefits of the program included a reduction in positive symptoms and in symptom exacerbations and an increase in the percent of days of abstinence from drugs or alcohol over the 12-month period from baseline to follow-up.

CONCLUSIONS

These findings demonstrate the effectiveness of a program of routine care integrated with motivational interviewing, cognitive behavior therapy, and family intervention over routine psychiatric care alone for patients with comorbid schizophrenia and alcohol or drug abuse or dependence.

Expression of the Oct-1 transcription factor and characterization of its interactions with the Bob1 coactivator

The Oct-1 transcription factor regulates a variety of tissue-specific and general housekeeping genes by recruiting specialized coactivators of transcription. It acts synergistically with the B-cell-specific coactivator Bob1 (OCA-B, OBF-1) to stimulate transcription of immunoglobulin genes. To analyze Oct-1's interactions with Bob1 and other regulatory proteins, we have overexpressed and purified different functional domains of the recombinant proteins. A version of Oct-1 that encompasses the amino-terminal activation region and the POU DNA-binding domain was extensively characterized (OctDeltaC1; comprising residues 1-445). Using an in vitro transcription assay, we demonstrate that this fragment is sufficient and necessary to stimulate transcription from an immunoglobulin promoter with Bob1. It also coactivates from the herpes simplex virus ICPO promoter element in the presence of VP16. Using a range of spectroscopic and biophysical techniques, we demonstrate that the activation domains of Oct-1 and Bob1 have little globular structure and that they do not physically interact. Thus, their functional synergy is likely to arise by the co-recruitment of common factors as part of a larger regulatory assembly. We propose a hypothesis to explain why the activation domains of these and other transcription factors of metazoans have little if any intrinsic structure.

Mood changes in adolescents using depot-medroxyprogesterone acetate for contraception: a prospective study

STUDY OBJECTIVE

Depot-medroxyprogesterone acetate (DMPA) is thought to cause changes in mood among patients using it for contraception. The purpose of this study was to evaluate changes in negative and positive affect among adolescent females using DMPA as a contraceptive agent.

DESIGN, SETTING, PARTICIPANTS

This prospective study was set in an urban hospital adolescent clinic. Thirty-nine adolescents choosing DMPA as a contraceptive agent and 24 adolescents not using any hormonal contraception were enrolled as subjects and controls, respectively. Two standardized questionnaires, the Beck Depression Inventory (BDI) and the Multiple Affect Adjective Checklist-Revised (MAACL-R), were administered at baseline to all participants and readministered at 3, 6, and 12 months.

MAIN OUTCOME MEASURES

Changes in negative affect from baseline to 3, 6, and 12 months were evaluated by the BDI and by "dysphoria" subscale scores of the MAACL-R. Paired t-tests were used to measure these changes in subjects and controls separately.

RESULTS

The mean change in BDI scores from baseline to one year for those who completed one year was -4.8 for subjects (P =.02) and +.3 (P =.84) for controls. The mean change in the dysphoria subscale scores was -5.7 (P =.21) for the subjects and -.1 (P =.98) for the controls while the change in the positive affect scores over a period of one year were -2.1 (P =.46) and +.1 (P =.98) for subjects and controls, respectively.

CONCLUSIONS

Adolescents using DMPA do not show depressive symptoms when using DMPA as a contraceptive agent over a period of 12 months as measured by the BDI and show no significant changes in negative or positive affect as measured by the MAACL-R.

A structural characterization of the interactions between titin Z-repeats and the alpha-actinin C-terminal domain

Titin and alpha-actinin, two modular muscle proteins, are with actin the major components of the Z-band in vertebrate striated muscles where they serve to organize the antiparallel actin filament arrays in adjacent sarcomeres and to transmit tension between sarcomeres during activation. Interactions between titin and alpha-actinin have been mainly localized in a 45-amino acid multiple motif (Z-repeat) in the N-terminal region of titin and the C-terminal region of alpha-actinin. In this study, we provide the first quantitative characterization of alpha-actinin-Z-repeat recognition and dissect the interaction to its minimal units. Different complementary techniques, such as circular dichroism, calorimetry, and nuclear magnetic spectroscopy, were used. Two overlapping alpha-actinin constructs (Act-EF34 and Act-EF1234) containing two and four EF-hand motifs, respectively, were produced, and their folding properties were examined. Complex formation of Act-EF34 and Act-EF1234 with single- and double-Z-repeat constructs was studied. Act-EF34 was shown quantitatively to be necessary and sufficient for binding to Z-repeats, excluding the presence of additional high-affinity binding sites in the remaining part of the domain. The binding affinities of the different Z-repeats for Act-EF34 range from micromolar to millimolar values. The strongest of these interactions are comparable to those observed in troponin C-troponin I complexes. The binding affinities for Act-EF34 are maximal for Zr1 and Zr7, the two highly homologous sequences present in all muscle isoforms. No cooperative or additional contributions to the interaction were observed for Z-repeat double constructs. These findings have direct relevance for evaluating current models of Z-disk assembly.

Site-specific cation binding mediates TATA binding protein-DNA interaction from a hyperthermophilic archaeon

Pyrococcus woesei (Pw) is a hyperthermophilic archaeal organism that exists under conditions of high salt and elevated temperature. In a previous study [O'Brien, R., DeDecker, B., Fleming, K., Sigler, P. B., and Ladbury, J. E., (1998) J. Mol. Biol. 279, 117-125], we showed that, despite the similarity of primary and secondary structure, the TATA box binding protein (TBP) from Pw binds thermodynamically in a fundamentally different way to its mesophilic counterparts. The affinity of the interaction increases as the salt concentration is increased. The formation of the protein-DNA complex involves the release of water and the uptake of ions, which were hypothesized to be cations. Here we test this hypothesis by selecting potential cation binding sites at negatively charged, acidic residues in the complex interface. These were substituted using site-directed mutagenesis of specific residues. Changes in the thermodynamic parameters on formation of the mutant protein-DNA complex were determined using isothermal titration calorimetry and compared to the wild type interaction. Removal of a glutamate residue from the binding site resulted in the uptake of one less cation on formation of the complex. This glutamate (E12) is directly involved in the binding of cations in the complex interface. Substitution of another acidic residue proximal to the DNA binding site (D101) had no effect on cation uptake, suggesting that the location of the amino acid on the protein surface is important in dictating the potential to coordinate cations. Removal of the cation binding site provided a more favorable entropy of binding; however, this effect is significantly reduced at higher salt concentrations. The removal of the cation binding site led to an increase in affinity with respect to the wild-type TBP at low salt concentrations.

Mycophenolate mofetil: a safe and promising immunosuppressant in neuromuscular diseases

The authors report the use mycophenolate mofetil (MM) in the treatment of neuromuscular diseases. Thirty-eight patients (32 with MG, three with inflammatory myopathy, and three with chronic acquired demyelinating neuropathy) were treated with MM for an average duration of 12 months. All patients tolerated MM without major side effects. Twenty-four patients improved either in their functional status or in their ability to reduce corticosteroid dose. Mean time to improvement was 5 months.

Structural basis for recognition of dipeptides by peptide transporters

Our objective in this work was to identify the structural basis for the molecular recognition of peptides by peptide transporters. Various assays for dipeptide transport by the dipeptide and tripeptide permeases of Escherichia coli were performed, together with measurements of thermodynamic parameters of substrate binding to the dipeptide binding protein using isothermal titration calorimetry. Computer-based conformational analysis of the test dipeptides was performed to define the repertoire of conformers that each dipeptide adopts in solution. Strict correlations were identified between the complement of particular conformers adopted by a peptide and its bioactivity as a substrate for each transporter. Details of the structural and electronic parameters that define the molecular recognition templates (MRTs) of the dipeptide substrates of these transporters are presented; similar MRTs are likely to apply with dipeptidases. These MRTs provide the essential information for the rational design of peptide-based drugs tailored for exploitation of peptide transporters in microorganisms and man.

Regulation of phosphoenolpyruvate carboxykinase and insulin-like growth factor-binding protein-1 gene expression by insulin. The role of winged helix/forkhead proteins

Winged helix/forkhead (Fox) transcription factors have been implicated in the regulation of a number of insulin-responsive genes. The insulin response elements (IREs) of the phosphoenolpyruvate carboxykinase (PEPCK) and insulin-like growth factor-binding protein-1 (IGFBP-1) genes bind members of the FKHR and HNF3 subclasses of Fox proteins. Previous mutational analyses of the PEPCK and IGFBP-1 IREs revealed mutations which do not affect the binding of HNF3 proteins to these elements but do eliminate the ability of the IREs to mediate an insulin response. This dissociation of binding and function provided compelling evidence that HNF3 proteins, per se, are not insulin response proteins. The same approach was used here to determine if FKHRL1, a member of the FKHR subclass of Fox proteins, binds to the PEPCK and IGFBP-1 IREs in a manner that correlates with the ability of these elements to mediate an insulin response. Overexpression of FKHRL1 stimulates transcription from transfected reporter constructs that contain a multimerized PEPCK IRE or an IGFBP-1 IRE and this stimulation is repressed by insulin. There is a direct correlation between the ability of mutant versions of the PEPCK and IGFBP-1 IREs to bind FKHRL1 and their ability to mediate FKHRL1-induced transcription when FKHRL1 is overexpressed. However, under conditions where FKHRL1 is not overexpressed, there is a lack of correlation between FKHRL1 binding to mutant versions of the PEPCK and IGFBP-1 IREs and the ability of these elements to mediate an insulin response. Therefore, the PEPCK and IGFBP-1 IREs mediate FKHRL1-induced transcription and its inhibition by insulin when this protein is overexpressed, but at the normal cellular concentration of FKHRL1 the insulin response mediated by these elements must involve another protein.

Characterization of the Mycobacterium bovis restriction fragment length polymorphism DNA probe pUCD and performance comparison with standard methods

In this study, the newly described Mycobacterium bovis restriction fragment length polymorphism (RFLP) typing probe pUCD was characterized by sequence analysis and the previously observed polymorphic banding pattern was reproduced with a combination of three oligonucleotide probes in a single, mixed hybridization. In addition, the ability of pUCD to distinguish between 299 M. bovis isolates from the Republic of Ireland was assessed in relation to established methods and a statistical function for objective comparison of RFLP probes was derived. It was found that typing with pUCD alone produced greater discrimination between M. bovis isolates than typing with the commonly used mycobacterial DNA probes IS6110, PGRS, and DR and also by the spoligotyping technique. pUCD and DR in combination produced the highest level of discrimination while maintaining a high level of concordance with known epidemiological data relating to the samples. The reduction of pUCD to the level of oligonucleotides should in future allow pUCD and DR to be included together in a mixed hybridization, thus producing a high level of M. bovis strain type discrimination from a single round of RFLP analysis.

The ATPase cycle of Hsp90 drives a molecular 'clamp' via transient dimerization of the N-terminal domains

How the ATPase activity of Heat shock protein 90 (Hsp90) is coupled to client protein activation remains obscure. Using truncation and missense mutants of Hsp90, we analysed the structural implications of its ATPase cycle. C-terminal truncation mutants lacking inherent dimerization displayed reduced ATPase activity, but dimerized in the presence of 5'-adenylamido-diphosphate (AMP-PNP), and AMP-PNP- promoted association of N-termini in intact Hsp90 dimers was demonstrated. Recruitment of p23/Sba1 to C-terminal truncation mutants also required AMP-PNP-dependent dimerization. The temperature- sensitive (ts) mutant T101I had normal ATP affinity but reduced ATPase activity and AMP-PNP-dependent N-terminal association, whereas the ts mutant T22I displayed enhanced ATPase activity and AMP-PNP-dependent N-terminal dimerization, indicating a close correlation between these properties. The locations of these residues suggest that the conformation of the 'lid' segment (residues 100-121) couples ATP binding to N-terminal association. Consistent with this, a mutation designed to favour 'lid' closure (A107N) substantially enhanced ATPase activity and N-terminal dimerization. These data show that Hsp90 has a molecular 'clamp' mechanism, similar to DNA gyrase and MutL, whose opening and closing by transient N-terminal dimerization are directly coupled to the ATPase cycle.

Localization and characterization of the hyaluronan-binding site on the link module from human TSG-6

BACKGROUND

The interactions of hyaluronan (HA) with proteins are important in extracellular matrix integrity and leukocyte migration and are usually mediated by a domain termed a Link module. Although the tertiary structure of a Link module has been determined, the molecular basis of HA-protein interactions remains poorly understood.

RESULTS

Isothermal titration calorimetry was used to characterize the interaction of the Link module from human TSG-6 (Link_TSG6) with HA oligosaccharides of defined length (HA(4)-HA(16)). All oligomers bound (except HA(4)) with K(d) values ranging from 0.2-0.5 microM at 25 degrees C. The reaction is exothermic with a favourable entropy and the thermodynamic profile is similar to those of other glycosaminoglycan-protein interactions. The HA(8) recognition site on Link_TSG6 was localized by comparing nuclear magnetic resonance (NMR) spectra from a 1:1 complex with free protein. Residues perturbed on HA binding include both amino acids that are likely to be directly involved in the interaction (i.e., Lys11, Tyr59, Asn67, Phe70, Lys72 and Tyr78) and those affected by a ligand-induced conformational change in the beta4/beta5 loop. The sidechain of Asn67 becomes more rigid in the complex suggesting that it is in close proximity to the binding site.

CONCLUSIONS

In TSG-6 a single Link module is sufficient for a high-affinity interaction with HA. The HA-binding surface on Link_TSG6 is found in a similar position to that suggested previously for CD44, indicating that its location might be conserved across the Link module superfamily. Here we find no evidence for the involvement of linear sequence motifs in HA binding.

Novel germline mutations in the PTEN tumour suppressor gene found in women with multiple cancers

Germline mutations in PTEN can predispose people to Cowden syndrome (CS) and Bannayan-Ruvalcaba-Riley (BRR) syndrome, rare, autosomal dominantly inherited neoplastic disorders. To determine whether germline mutations in PTEN contribute to genetic predisposition to multiple primary tumours within the general population, we conducted a nested case-control study, among 32 826 members of the prospective Nurses' Health Study cohort; cases were women with more than one primary tumour at different anatomical sites. We screened all nine exons of PTEN and flanking intronic splice sites for all 103 eligible cases using SSCP and sequencing. We observed two novel germline heterozygous missense mutations in exon 5 in five of the cases; three were V119L and two were V158L. Neither mutation was observed in 115 controls free of diagnosed cancer (p = 0.02). Both mutants showed partial tumour suppressor activity when compared to wild type PTEN when transfected into a PTEN null breast cancer cell line. The phenotype was cell line specific suggesting that genetic background affects growth suppression activity of the mutants. These data provide evidence that germline mutations in PTEN may be a more frequent predisposing factor for cancers in women than previously suggested.

Identification of a novel DNA probe for strain typing Mycobacterium bovis by restriction fragment length polymorphism analysis

Bovine tuberculosis caused by Mycobacterium bovis remains a significant disease of farmed cattle in many countries despite ongoing tuberculosis eradication programs. Molecular typing methods such as restriction fragment length polymorphism (RFLP) analysis and spoligotyping have been used to identify related herd breakdowns in an attempt to identify more precisely the route of infection into cattle herds and to trace the transmission of bovine tuberculosis. A recent geographical survey of Irish M. bovis isolates demonstrated that a significant proportion of isolates ( approximately 20%) exhibit a common strain type, limiting the value of current strain typing methods as an epidemiological tool. We have identified and cloned a region of the M. bovis genome, pUCD, which generates a clear, highly polymorphic banding pattern when used as an RFLP probe on AluI restriction-digested M. bovis genomic DNA and which effectively subdivides this common strain type. When used to type 60 Irish M. bovis isolates, pUCD exhibited greater discriminatory power than the commonly used mycobacterial RFLP probes IS6110, PGRS, and DR and detected an equivalent number of strain types to a combination of these three probes. pUCD also detected significantly more strain types than the spoligotyping technique, while maintaining a high level of concordance between epidemiologically related and unrelated herd breakdowns. The polymorphic element within pUCD remains to be fully characterized, however the potential for this probe to greatly decrease the workload necessary to genotype M. bovis by RFLP analysis is compelling.