Persisting speech difficulties at 7-8 years of age - a longitudinal study of speech production in internationally adopted children with cleft lip and palate

AIM

To longitudinally investigate speech production (consonant proficiency, consonant errors and perceived velopharyngeal competence) in 17 internationally adopted (IA) children with unilateral cleft lip and palate (UCLP) at three time points.

METHOD

Consonant proficiency (percent consonants correct, consonant inventory) and number and type of consonant errors were calculated based on blind phonetic transcriptions of words from the Swedish Test of Articulation and Nasality (SVANTE). Velopharyngeal competence was perceptually rated by three blinded experienced speech-language pathologists at the ages of 3, 5 and 7-8 years.

RESULTS

A significant positive development of speech production was found, although most children still scored very low for consonant proficiency at the age of 7-8 compared with normative values: the median for percent consonants correct was 79.7 and many children still had persisting cleft-related and developmental consonant errors. At the age of 7-8, almost half of the children were rated as having a competent velopharyngeal function and only three as having an incompetent velopharyngeal function.

CONCLUSION

Persisting speech difficulties at school age in IA children with UCLP were found in the present study, which is one of the very few longitudinal studies. Our results highlight the need for detailed follow-up of speech production in clinical settings. Speech disorders may have a severe impact on a child's intelligibility and participation with peers, and there is a need for more studies investigating the actual everyday effect of the difficulties found.

Facing an unexpected reality - oscillating between health and suffering 4-6 years after bariatric surgery

BACKGROUND

Obesity is a significant public health problem that is on the increase worldwide, and treatment with bariatric surgery is becoming more and more common. This type of surgery has proved to be good for weight reduction and for preventing complications, but few studies have investigated patients' long-term experiences of health and suffering.

AIM

To explore people's experiences of health after bariatric surgery. What are their thoughts about their life, body and sexuality?

METHODS

This study is based on semi-structured interviews with eight women and eight men, 4-6 years after bariatric surgery. The data were analysed using qualitative content analysis and resulted in 5 main themes and 14 subthemes.

RESULTS

The new body enabled a healthy life due to better treatment in society, enhanced self-esteem, the pleasure of purchasing clothes and the courage to become more sexually active. At the same time, the body could be experienced as so unfamiliar that their life was dominated by despondency, a lack of freedom and a feeling of being lost, which made them wish to return to their old body.

CONCLUSION AND IMPLICATIONS

The participants received extensive information before as well as follow-up conversations up to one year after surgery. Nevertheless, they all experienced that changing from life as an obese person to a radically reduced body often meant a confrontation with an unexpected reality that oscillated between health and suffering. This indicates that preparedness for the life changes that bariatric surgery may entail is inadequate and that moving towards health and suffering takes its own time. Therefore, more time should be allocated to talking about how life is and can become in the long term, which may facilitate a dialogical, person-centred approach to the setbacks and situations each person needs to manage in order to improve her/his health.

The physical and mental impact of surviving sepsis - a qualitative study of experiences and perceptions among a Swedish sample

BACKGROUND

Sepsis is a critical illness with high morbidity and mortality rates. Each year, sepsis affects about 48.9 million people all over the world. This study aims to illuminate how sepsis survivors experience sepsis and the impact of sepsis, as well as the health-related quality of life thereafter.

METHODS

An interview study with eight sepsis survivors was carried out in Sweden with an inductive qualitative method. The data were analyzed with content analysis.

RESULTS

Four themes were identified during the analysis; The experience of health care and being a sepsis patient, New circumstances´ impact on life, Family and social interactions, and The psychological impact on life. The lack of information about how sepsis can impact the survivors' lives and what to expect can lead to prolonged agony. The long recovery time comes as an unexpected and unpleasant surprise to those affected. Initially, the sepsis survivors are almost euphoric that they have survived, which can later lead to chock and trauma when they realize that they could have died. This insight needs to be processed in order to reach reconciliation with life after sepsis.

CONCLUSION

Sepsis has a huge impact on both physical and mental aspects of life. Many survivors suffer from persistent residual symptoms of varying degrees, to which they have to adapt. The sepsis survivors need individually adjusted information about the sepsis recovery trajectory, and what to expect during and after the hospital stay.

Internationally adopted children with and without a cleft lip and palate showed no differences in language ability at school-age

AIM

The aim of this study was to investigate language ability in internationally adopted children aged 7-8 years with and without a unilateral cleft lip and palate.

METHODS

We compared 27 internationally adopted children with a unilateral cleft lip and palate, adopted from China, with a group of 29 children without a cleft lip and palate, adopted from different countries. Participants were recruited from two cleft lip and palate teams in Sweden and through adoption organisations. Assessments were performed using standardised tests of speech and of receptive and expressive language ability. In addition, a parental questionnaire in which speech, language and communication aspects were rated was used.

RESULTS

There were no significant differences in language ability between the groups. The only difference was related to speech ability, where the internationally adopted children with unilateral cleft lip and palate scored significantly lower. However, a high proportion of children in both groups scored low on measures of expressive language compared with test norms.

CONCLUSION

The results suggested that having a cleft lip and palate did not increase the risk of language difficulties. Instead, being internationally adopted may be associated with a risk of delayed language development lasting for several years post-adoption.

Internationally Adopted Children With Unilateral Cleft Lip and Palate-Consonant Proficiency and Perceived Velopharyngeal Competence at the Age of 5

OBJECTIVE

To compare consonant proficiency, consonant errors, and the perceived velopharyngeal (VP) competence in internationally adopted (IA) children with unilateral cleft lip and palate (UCLP) and nonadopted (NA) children with the same cleft-palate type at age 5.

DESIGN

Case-control study based on phonetic transcriptions of standardized speech recordings of 5-year-olds at a tertiary hospital.

PARTICIPANTS

Twenty-five IA children were compared to 20 NA children. All consecutive patients at a cleft lip and palate center participated.

MAIN OUTCOME MEASURE(S)

Consonant proficiency was measured using percentage consonants correct, percentage consonants correct-adjusted for age, percentage correct place, percentage correct manner, and consonant inventory. Cleft speech characteristics (CSCs), developmental speech characteristics (DSCs), and the perceived VP competence were also measured.

RESULTS

The IA children had significantly lower values for all consonant proficiency variables (p < .05) and a smaller consonant inventory (p = .001) compared to the NA children. The IA children had a higher frequency of CSCs (IA = 84%, NA = 50%, p < .05) and DSCs (IA = 92%, NA = 65%, p = .057), and twice as many IA children as NA children had perceived VP incompetence (IA = 52%, NA = 25%, p = .17).

CONCLUSIONS

Severe speech disorder was more common in IA children than in NA children at age 5. Most importantly, the speech disorders seem to be not only cleft-related. More detailed speech assessments with a broader focus are needed for IA children with UCLP. Longitudinal studies are recommended to further investigate the impact of speech difficulties in IA children's daily lives.

Speech production in 3-year-old internationally adopted children with unilateral cleft lip and palate

BACKGROUND

In the last decade, a large number of children with cleft lip and palate have been adopted to Sweden. A majority of the children were born in China and they usually arrive in Sweden with an unoperated palate. There is currently a lack of knowledge regarding speech and articulation development in this group of children, who also have to deal with a late first language switch.

AIMS

To study consonant proficiency in 3-year-old internationally adopted children with unilateral cleft lip and palate (UCLP) compared with peers with UCLP born in Sweden. Also to study the type and frequency of consonant errors and to perceptually compare velopharyngeal competence between the groups.

METHODS & PROCEDURES

Thirty-two children born between 2006 and 2010 with UCLP participated in the study-14 adopted from China and 18 children born in Sweden. Both groups were treated by the same cleft palate team. Audio recordings at 3 years of age were perceptually analysed by blinded listeners. Consonant proficiency was measured via per cent consonants correct adjusted for age (PCC-A), per cent correct manners (PCM) and per cent correct places (PCP). The prevalence of audible nasal air leakage and velopharyngeal competence were judged and compared between groups. The type and frequencies of consonant errors related to place and manner of articulation were also analysed.

OUTCOMES & RESULTS

The internationally adopted children had significantly fewer correct consonants compared with the Swedish-born children. This was true for PCC-A, PCP and PCM. This group also had significantly higher prevalence of glottal stops/fricatives and deleted target consonants more often. Also the internationally adopted children had a higher prevalence of incompetent velopharyngeal function. The only outcome variable with similar results in the groups was audible nasal air leakage.

CONCLUSIONS & IMPLICATIONS

The present study indicated that there were significant differences regarding consonant proficiency and velopharyngeal competence between internationally adopted children with a UCLP and their Swedish-born peers with UCLP at the age of 3 years. Internationally adopted children with UCLP should be considered an at risk group for a higher prevalence of speech difficulties than non-adoptees. Thus, it is particularly important to follow this group of children over time. Longitudinal studies of speech and language development in internationally adopted children with UCLP are needed.

Duration of methicillin-resistant Staphylococcus aureus colonization after diagnosis: a four-year experience from southern Sweden

BACKGROUND

The duration of colonization with methicillin-resistant Staphylococcus aureus (MRSA) is not well known and there is debate as to whether a patient colonized with MRSA ever can be defined as 'MRSA-negative'.

METHODS

Since 2003 all notified MRSA cases have been systematically followed in Skåne County, southern Sweden. Cultures are taken from the nares, throat, perineum and possible skin lesions. Contact tracing is conducted. The screening program continues as long as cultures are positive and then until 1 y of consecutive negative cultures for MRSA is completed.

RESULTS

Of the 578 MRSA cases during 2003-2006, 535 were included in this retrospective study. The median duration of colonization with MRSA was 5.9 months. Having household contacts with MRSA, young age, spa-type t002 and colonization in 2 or more locations, were significantly associated with a longer duration of colonization. Having a clinical infection treated with antibiotics (compared to clinical infection with no antibiotic treatment or asymptomatic carriage) was significantly associated with a shorter carriage time. Eradication treatment was associated with a shorter carriage time.

CONCLUSION

These results may have implications for the management of patients with MRSA carriage. The study indicates that MRSA carriage can be defined as 'negative' in a follow-up program and shows the importance of performing contact tracing among household members.

Parents' experiences of an abnormal ultrasound examination - vacillating between emotional confusion and sense of reality

Background

An ultrasound examination is an important confirmation of the pregnancy and is accepted without reflection to any prenatal diagnostic aspects. An abnormal finding often comes unexpectedly and is a shock for the parents. The aim was to generate a theoretical understanding of parents' experiences of the situation when their fetus is found to have an abnormality at a routine ultrasound examination.

Methods

Sixteen parents, mothers and fathers, whose fetus had been diagnosed with an abnormality during an ultrasound scan in the second or third trimester, were interviewed. The study employed a grounded theory approach.

Results

The core category vacillating between the emotional confusion and sense of reality is related to the main concern assessment of the diagnosis impact on the well-being of the fetus. Two other categories Entering uncertainty and Involved in an ongoing change and adaptation have each five sub-categories.

Conclusions

Parents are aware of that ultrasound examination is a tool for identifying abnormalities prenatally. The information about the abnormality initially results in broken expectations and anxiety. Parents become involved in ongoing change and adaptation. They need information about the ultrasound findings and the treatment without prolonged delay and in a suitable environment. The examiner who performs the ultrasound examination must be aware of how anxiety can be intensified by environmental factors. All parents should to be offered a professional person to give them support as a part of the routine management of this situation.

Parents' worried state of mind when fetal ultrasound shows an unexpected finding: a comparative study

OBJECTIVE

Most parents yearn for a second-trimester ultrasound examination and feel excitement about it, but some also worry about what the examination will show. According to prior research, using only generic instruments or specific questionnaires, anxiety decreases when the ultrasound findings are normal. The aim of this study was to compare parents' worry (Parents' Expectations, Experiences, and Reactions to Ultrasound [PEER-U] State of Mind Index) and sense of coherence before and after a routine second-trimester ultrasound examination when it showed normal or abnormal findings.

METHODS

A 1-year cohort study was performed at a Swedish university hospital. A total of 2049 parents who had their second-trimester ultrasound examinations there filled in a questionnaire consisting of 2 parts before and after the examinations.

RESULTS

Parents with normal ultrasound findings were less worried than parents with abnormal findings. The group with normal findings also showed less worry after the examination than before. A sex analysis showed similar patterns.

CONCLUSIONS

Parents with abnormal ultrasound findings are more worried and anxious. The new instrument, the PEER-U State of Mind Index, not only measures parents' worry but can also expose what influences their ultrasound examination experience.

Residue 234 in glutathione transferase T1-1 plays a pivotal role in the catalytic activity and the selectivity against alternative substrates

GST (glutathione transferase) T1-1 plays an important role in the biotransformation of halogenated alkanes, which are used in large quantities as solvents and occur as environmental pollutants. Many reactions that are catalysed by GST T1-1 qualify as detoxification processes, but some reactions with dihalogenated alkanes lead to reactive products more toxic than the substrates. Murine GST T1-1 is particularly active with dichloromethane, which may explain the high carcinogenicity of dichloromethane in the mouse. Human GST T1-1 activity is considerably lower with halogenated hydrocarbons and some related substrates. Human GST T1-1 is polymorphic with a frequent null phenotype, suggesting that it is advantageous, under some circumstances, to lack the functional enzyme, which catalyses GSH conjugations that may cause bioactivation. The present study shows that amino acid residue 234 is a determinant of the differences in catalytic efficiency between the human and the rodent enzymes. The replacement of Trp234 in human GST T1-1 by arginine, found in the rodent enzyme, enhanced the alkyltransferase activity by an order of magnitude with a series of homologous iodoalkanes and some typical GST substrates. The specific activity of the alternative mutant Trp234-->Lys was lower than for the parental human GST T1-1 with many substrates, showing that a positive charge is not sufficient for increased activity. The enhanced activity of Trp234-->Arg with alkylating agents was dependent on the substrate tested, whereas no increase of the peroxidase activity with cumene hydroperoxide was noted. Residue 234 therefore is also involved in the control of the substrate selectivity of GST T1-1.

Evaluation of a consecutive group of transsexual individuals referred for vocal intervention in the west of Sweden

Male-to-female transsexual individuals frequently experience difficulties in increasing the fundamental frequency so that they can pass as members of the preferred gender. Female-to-male individuals may also meet with vocal problems although hormone treatment lowers fundamental frequency. The purpose of this study was to explore the transsexual individuals who, as part of their reassignment process, were referred to the voice clinic at the Sahlgrenska University Hospital in Göteborg, Sweden, between 1991 and 2002. The group comprised 22 male-to-female and 3 female-to-male transsexuals. Video recorded laryngeal examinations revealed basically normal conditions. More than half the patients showed supraglottal constriction on phonating at both habitual and preferred levels. A comparison between acoustic analyses before therapy and at follow-up visits showed increased fundamental frequencies for male-to-female individuals (p = < 0.01). Vocal fatigue was reduced. Degree of satisfaction with the post-therapy voice was not related to number of therapy sessions.

Specific mediator inhibition by the NO donors SNP and NCX 2057 in the peripheral lung: implications for allergen-induced bronchoconstriction

Background

The aim of this study was to examine potential therapeutic effect of the two NO donors NCX 2057 (3-(4-hydroxy-3-methoxyphenyl)-2-propenoic acid) 4-(nitrooxy)butyl ester) and SNP (sodium nitroprusside) on the early allergic airway response in the peripheral lung.

Methods

The experiments were performed in guinea pig lung parenchyma (GPLP) derived from ovalbumin (OVA) sensitized guinea pigs. The effects of NCX 2057 and SNP were evaluated by contractile responses and mediator release during OVA challenge. The generation of nitrite and nitrate was assessed by chemiluminescence. Statistical analysis was evaluated by ANOVA.

Results

Cumulatively increasing concentrations of OVA (1–10,000 ng/ml) induced concentration-dependent contractions of the GPLP that were reduced by NCX 2057 (100 μM, p < 0.001) and SNP (100 μM, p < 0.05). Antigen-induced eicosanoid release was decreased by NCX 2057 (100 μM, p < 0.001) but not by SNP (100 μM), whereas the release of histamine was reduced by SNP (100 μM, p < 0.001) but not by NCX 2057 (100 μM). In addition, NCX 2057 (0.1–100 μM), but not SNP (0.1–100 μM), relaxed leukotriene D₄ (10 nM) precontracted GPLP (p < 0.01). The guanylyl cyclase inhibitor ODQ had no effect on the NCX 2057 mediated relaxation. SNP released significantly less nitrite than NCX 2057.

Conclusion

Although both SNP and NCX 2057 reduced the release of pro-inflammatory mediators, their profiles were distinctly different. Furthermore, NCX 2057 also induced smooth muscle dilation in the GPLP. The findings point to specific anti-inflammatory effects of different NO donors in the peripheral lung tissue.

Parental level of anxiety, sense of coherence and state of mind when choroid plexus cysts have been identified at a routine ultrasound examination in the second trimester of pregnancy: a case control study

The aim of the study was to compare parents' experience of a routine ultrasound examination in the second trimester, when a choroid plexus cyst/cysts (CPC) were found (Study group; n = 22), with matched controls where no fetal deviations were identified (Control group, n = 66). All the parents had participated in a larger cohort study. The instruments used for measuring anxiety were STAI-state/trait, sense of coherence (SOC) and Parents' Expectations, Experiences, Reactions to an Ultrasound examination during pregnancy (PEER-U, State of Mind Index). Regarding the SOC and STAI-state/trait no significant differences were found between the cases and controls or within the respective group before and after the ultrasound examination. The cases had an increase in anxiety (more anxious) as measured by the instrument PEER-U after the examination, while the controls showed a significant better level of State of Mind Index (less anxious) after the examination, compared to before. Therefore PEER-U can be a more reliable instrument when studying state of mind (anxiety) in connection with ultrasound examinations, and as it is specific for this situation it does not appear to be time dependent.

Information for better or for worse: interviews with parents when their foetus was found to have choroid plexus cysts at a routine second trimester ultrasound

The aim of the study was to gain a theoretical understanding of parents' experiences and handling of the situation, when their foetus was diagnosed as having choroid plexus cysts, at a routine second trimester ultrasound examination. Nine couples and one mother were interviewed using one open question. Analysis method was Grounded Theory. The main concern was anxiety and the core category became need for knowledge. The other categories were frightening and confusing, judging risk and making a choice and comforting. The parents felt information during the ultrasound examination was insufficient. The time delay between the diagnosis and the doctor's appointment was also often criticized. Most of the parents in this study wanted to know what can be diagnosed by ultrasound, even if there is a small risk that the child will have a malformation or chromosome abnormality. However, when the diagnosis is made, they need adequate information, otherwise unnecessary anxiety arises. By giving sufficient information without days of delay, anxiety can hopefully be minimized. Some written information was also requested. It is of utmost importance that the staff use the same terminology and the correct name of the soft marker to the parents.

Lipid metabolites as regulators of airway smooth muscle function

Compelling evidence identifies airway smooth muscle (ASM) not only as a target but also a cellular source for a diverse range of mediators underlying the processes of airway narrowing and airway hyperresponsiveness in diseases such as asthma. These include the growing family of plasma membrane phospholipid-derived polyunsaturated fatty acids broadly characterised by the prostaglandins, leukotrienes, lipoxins, isoprostanes and lysophospholipids. In this review, we describe the enzymatic and non-enzymatic biosynthetic pathways of these lipid mediators and how these are influenced by drug treatment, oxidative stress and airways disease. Additionally, we outline their cognate receptors, many of which are expressed by ASM. We describe potential deleterious and protective roles for these lipid mediators in airway inflammatory and remodelling processes by describing their effects on diverse functions of ASM in asthma that have the potential to contribute to asthma pathogenesis and symptoms. These functions include contractile tone development, cytokine and extracellular matrix production, and cellular proliferation and migration.

Multivariate-activity mining for molecular quasi-species in a glutathione transferase mutant library

A library of recombinant glutathione transferases (GSTs) generated by shuffling of DNA encoding human GST M1-1 and GST M2-2 was screened with eight alternative substrates, and the activities were subjected to multivariate analysis. Assays were made in lysates of bacteria in which the GST variants had been expressed. The primary data showed clustering of the activities in eight-dimensional substrate-activity space. For an incisive analysis, the rows of the data matrix, corresponding to the different enzyme variants, were individually scaled to unit length, thus accounting for different expression levels of the enzymes. The columns representing the activities with alternative substrates were subsequently individually normalized to unit variance and a zero mean. By this standardization, the data were adjusted to comparable orders of magnitude. Three molecular quasi-species were recognized by multivariate K-means and principal component analyses. Two of them encompassed the parental GST M1-1 and GST M2-2. A third one diverged functionally by displaying enhanced activities with some substrates and suppressed activities with signature substrates for GST M1-1 and GST M2-2. A fourth cluster contained mutants with impaired functions and was not regarded as a quasi-species. Sequence analysis of representatives of the mutant clusters demonstrated that the majority of the variants in the diverging novel quasi-species were structurally similar to the M1-like GSTs, but distinguished themselves from GST M1-1 by a Ser to Thr substitution in the active site. The data show that multivariate analysis of functional profiles can identify small structural changes influencing the evolution of enzymes with novel substrate-activity profiles.

Functionally diverging molecular quasi-species evolve by crossing two enzymes

Molecular evolution is frequently portrayed by structural relationships, but delineation of separate functional species is more elusive. We have generated enzyme variants by stochastic recombinations of DNA encoding two homologous detoxication enzymes, human glutathione transferases M1-1 and M2-2, and explored their catalytic versatilities. Sampled mutants were screened for activities with eight alternative substrates, and the activity fingerprints were subjected to principal component analysis. This phenotype characterization clearly identified at least three distributions of substrate selectivity, where one was orthogonal to those of the parent-like distributions. This approach to evolutionary data mining serves to identify emerging molecular quasi-species and indicates potential trajectories available for further protein evolution.

Characterisation of guinea pig precision-cut lung slices: comparison with human tissues

Precision-cut lung slices (PCLS) allow comparison of the airway responses of different species under identical experimental conditions. The aim of this study was to establish and characterise PCLS from guinea pigs (GPs) and to compare them with human PCLS. GP PCLS were prepared according to previously published procedures with the exception that the agarose solution and the initial incubation medium contained isoproterenol to avoid post mortem airway contraction. The median effective concentrations (EC50, expressed as nM) for agonist-induced bronchoconstriction in GP and human PCLS, respectively, were: leukotriene D4 (1.8, 5.0); thromboxane (16, 1.3); serotonin (69, unresponsive); histamine (217, 2,170); and methacholine (231, 234). Allergen-induced bronchoconstriction of passively sensitised PCLS was attenuated by histamine or thromboxane-prostanoid receptor antagonists and was almost completely prevented by their combination with leukotriene receptor antagonists. Airways pre-contracted with methacholine were relaxed by the beta-agonist salbutamol or the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine. Simultaneous studies of airways and vessels are possible with, for example, EC50 values for endothelin-1 of 37 nM (pulmonary arteries), 10 nM (pulmonary veins) and 9.6 nM (airway). When compared with previous findings in rat and mouse, these data show that guinea pig lungs are a more appropriate model for human airway pharmacology than lungs from rats or mice.

Structural basis of the suppressed catalytic activity of wild-type human glutathione transferase T1-1 compared to its W234R mutant

The crystal structures of wild-type human theta class glutathione-S-transferase (GST) T1-1 and its W234R mutant, where Trp234 was replaced by Arg, were solved both in the presence and absence of S-hexyl-glutathione. The W234R mutant was of interest due to its previously observed enhanced catalytic activity compared to the wild-type enzyme. GST T1-1 from rat and mouse naturally contain Arg in position 234, with correspondingly high catalytic efficiency. The overall structure of GST T1-1 is similar to that of GST T2-2, as expected from their 53% sequence identity at the protein level. Wild-type GST T1-1 has the side-chain of Trp234 occupying a significant portion of the active site. This bulky residue prevents efficient binding of both glutathione and hydrophobic substrates through steric hindrance. The wild-type GST T1-1 crystal structure, obtained from co-crystallization experiments with glutathione and its derivatives, showed no electron density for the glutathione ligand. However, the structure of GST T1-1 mutant W234R showed clear electron density for S-hexyl-glutathione after co-crystallization. In contrast to Trp234 in the wild-type structure, the side-chain of Arg234 in the mutant does not occupy any part of the substrate-binding site. Instead, Arg234 is pointing in a different direction and, in addition, interacts with the carboxylate group of glutathione. These findings explain our earlier observation that the W234R mutant has a markedly improved catalytic activity with most substrates tested to date compared to the wild-type enzyme. GST T1-1 catalyzes detoxication reactions as well as reactions that result in toxic products, and our findings therefore suggest that humans have gained an evolutionary advantage by a partially disabled active site.

Inhibition of nitric-oxide synthase enhances antigen-induced contractions and increases release of cysteinyl-leukotrienes in guinea pig lung parenchyma: nitric oxide as a protective factor

Nitric oxide (NO) in exhaled air is a biomarker of airway inflammation. However, the role of NO in the peripheral lung is not known. The aim of this study was to determine the role of endogenous NO in antigen-induced contractions of ovalbumin (OVA)-sensitized guinea pig lung parenchyma (GPLP). The contraction in this in vitro model of the peripheral lung closely resembles the corresponding response in human airways. Cumulatively increasing concentrations (10-10,000 microg/l) of OVA induced concentration-dependent contractions of the GPLP that were enhanced by the NO synthase (NOS) inhibitors N(omega)-nitro-L-arginine (L-NOARG; 100 microM), N(omega)-monomethyl-L-arginine (100 microM), N(omega)-nitro-L-arginine methyl ester (100 microM), and N-(3-(aminomethyl)benzyl)acetamidine (1400W; 1 microM). The enhancement induced by L-NOARG was reversed by coadministration with the 5-lipoxygenase inhibitor (R)-2-[4-(quinolin-2-yl-methoxy)phenyl]-2-cyclopentyl acetic acid (BAY x1005; 3 microM), whereas coadministration of L-NOARG with the cyclooxygenase inhibitor indomethacin (10 microM) did not change the effect of L-NOARG alone. L-NOARG (100 microM) did not affect the cumulative concentration-response relations for either leukotriene (LT) D4 (0.1-100 nM) or histamine (1-30 microM). The NO donor NONOate (0.001-100 microM) was ineffective in GPLP but potently relaxed precontracted guinea pig pulmonary artery. Furthermore, L-NOARG enhanced the release of LTE4 and decreased the release of prostaglandin E2 induced by OVA. In conclusion, endogenous NO exerts an inhibitory effect on antigen-induced contractions in the peripheral lung. The action of NO apparently involves inhibition of the release of mediators rather than direct relaxation of airway smooth muscle. The findings support the belief that endogenous NO has a protective anti-inflammatory effect in the airways.

Directed enzyme evolution guided by multidimensional analysis of substrate-activity space

The directed evolution of protein function frequently involves identification of mutants with improved properties from a population of variants obtained by mutagenesis. The selection of clones to parent the subsequent generation is crucial to the continued creation of superior progeny. In the present study, multivariate analysis guided the evolution of human glutathione transferase (GST) T1-1 to 65-fold enhanced alkyltransferase activity. Six alternative substrates monitored the substrate-activity space that characterized a mutant library of enzymes, obtained by recombination of DNA and heterologous expression in Escherichia coli. A subset of mutants was identified by their proximity in the targeted region of six-dimensional factor space. DNA from these mutants was recombined to create a new generation of GST variants from which an improved enzyme was isolated. The multidimensional cluster analysis is applicable to quantitative properties in any population of molecules undergoing evolution and can guide the tailoring of proteins, nucleic acids and other chemical structures to novel and improved functions.

High-resolution capillary zone and gel electrophoresis of structurally similar amphipathic glutathione conjugates based on interaction with beta-cyclodextrins

The tripeptide glutathione is a prominent intracellular constituent that provides protection against genotoxic and carcinogenic electrophiles and is also a component of several biological signal substances. Glutathione conjugates, free glutathione, and glutathione disulfide contain charged amino acid residues, which contribute to solubility in aqueous media. However, the amphipathic nature of glutathione conjugates and the small differences that may distinguish the S substituents, pose analytical problems in their resolution. The present study demonstrates how homologous S-alkyl and S-benzyl conjugates of high structural similarity can be efficiently resolved by capillary electrophoresis. Inclusion of beta-cyclodextrins in the buffer or in a polyacrylamide gel affords baseline separation of the analytes. The separation methods described are applicable to enzyme assays in vitro and to the identification and quantification of glutathione conjugates of importance in toxicology and physiology. The contribution of beta-cyclodextrin to the separation is primarily based on interactions between its hydrophobic cavity and the S-alkyl and S-benzyl groups of the analytes.

An ensemble of theta class glutathione transferases with novel catalytic properties generated by stochastic recombination of fragments of two mammalian enzymes

The correlation between sequence diversity and enzymatic function was studied in a library of Theta class glutathione transferases (GSTs) obtained by stochastic recombination of fragments of cDNA encoding human GST T1-1 and rat GST T2-2. In all, 94 randomly picked clones were characterized with respect to sequence, expression level, and catalytic activity in the conjugation reactions between glutathione and six alternative electrophilic substrates. Out of these six different compounds, dichloromethane is a selective substrate for human GST T1-1, whereas 1-menaphthyl sulfate and 1-chloro-2,4-dinitrobenzene are substrates for rat GST T2-2. The other three substances serve as substrates for both enzymes. Through this broad characterization, we have identified enzyme variants that have acquired novel activity profiles that differ substantially from those of the original GSTs. In addition, the expression levels of many clones were improved in comparison to the parental enzyme. A library of mutants can thus display a distribution of properties from which highly divergent evolutionary pathways may emerge, resembling natural evolutionary processes. From the GST library, a clone was identified that, by the point mutation N49D in the rat GST T2-2 sequence, has a 1700% increased activity with 1-menaphthyl sulfate and a 60% decreased activity with 4-nitrophenethyl bromide. Through the N49D mutation, the ratio of these activities has thus been altered 40-fold. An extensive characterization of a population of stochastically mutated enzymes can accordingly be used to find variants with novel substrate-activity profiles and altered catalytic properties. Recursive recombination of selected sequences displaying optimized properties is a strategy for the engineering of proteins for medical and biochemical applications. Such sequential design is combinatorial protein chemistry based on remodeling of existing structural scaffolds and has similarities to evolutionary processes in nature.

Twinning and defects in N-Nb2O5

N-Nb(2)O(5) [C2/m (No. 12), a = 28.51, b = 3.830 and c = 17.48 A, and beta = 124.8 degrees ] has been investigated by means of selected-area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). N-Nb(2)O(5) is domain twinned, with the twin plane perpendicular to the c* axis. The domains are rather small and the domain twinning can sometimes be best explained as stacking faults. A second type of coherent twinning at an angle of 90 degrees to the other two domain directions was also found. These domains are linked together by areas containing blocks of different sizes, similar to the disordered block arrangement observed in M-Nb(2)O(5).

An evolutionary approach to the design of glutathione-linked enzymes

Studies of protein structure provide information about principles of protein design that have come into play in natural evolution. This information can be exploited in the redesign of enzymes for novel functions. The glutathione-binding domain of glutathione transferases has similarities with structures in other glutathione-linked proteins, such as glutathione peroxidases and thioredoxin (glutaredoxin), suggesting divergent evolution from a common ancestral protein fold. In contrast, the binding site for glutathione in human glyoxalase I is located at the interface between the two identical subunits of the protein. Comparison with the homologous, but monomeric, yeast glyoxalase I suggests that new domains have originated through gene duplications, and that the oligomeric structure of the mammalian glyoxalase I has arisen by 'domain swapping'. Recombinant DNA techniques are being used for the redesign of glutathione-linked proteins in attempts to create binding proteins with novel functions and catalysts with tailored specificities. Enzymes with desired properties are selected from libraries of variant structures by use of phage display and functional assays.

Molecular cloning and functional expression of the gene encoding the human proteinase-activated receptor 2

We previously reported the molecular cloning of a mouse guanosine-nucleotide-binding-protein-coupled receptor similar to the thrombin receptor. Since the physiological agonist was unknown, the receptor was named proteinase-activated receptor 2. We describe here the cloning and functional expression of the gene encoding the corresponding human receptor. The gene is divided into two exons separated by about 14 kb intronic DNA. The deduced protein sequence is 397 amino acids long and 83% identical to the mouse receptor sequence. Within the extracellular amino terminus, the residues predicted to form the tethered agonist ligand differ between the two receptors; of the first six residues only four are conserved. At positions five and six, a lysine residue and a valine residue, respectively, have replaced arginine and leucine residues found in the mouse sequence. When the human receptor is expressed in Chinese hamster ovary cells, it can be activated by low nanomolar concentrations of the serine proteinase trypsin and by peptides made from the receptor sequence. Northern-blot analysis of receptor expression showed that the receptor transcript is widely expressed in human tissues with especially high levels in pancreas, liver, kidney, small intestine and colon. Moderate expression was detected in many organs but none in brain or skeletal muscle. By fluorescence in situ hybridization, the human proteinase-activated receptor 2 gene was mapped to chromosomal region 5q13, where, previously, the related thrombin receptor gene has been located.

The mouse proteinase-activated receptor-2 cDNA and gene. Molecular cloning and functional expression

We have reported the cloning from mouse genomic DNA of a fragment encoding a G-protein-coupled receptor related to the receptor for the blood clotting enzyme thrombin. Like the thrombin receptor this receptor is activated by proteolytic cleavage of its extracellular amino terminus. Because the physiological agonist at the receptor was unknown, we provisionally named it proteinase-activated receptor 2 (PAR-2). Here we present a PAR-2 cDNA of 2729 nucleotides that differs from the published genomic sequence at the 5' end, including a part of the protein coding region. The differences do not affect the peptide sequence of the activating proteinase cleavage site proper, but may include amino acid residues important for enzyme-substrate recognition. Analysis of the PAR-2 gene structure showed that the cDNA 5' end is derived from a separate exon located about 10 kilobases away from the 3' exon. Results from a primer extension experiment indicate that transcription starts at a unique site around nucleotide -203 respective to the translation initiation ATG. Chinese hamster ovary cells transfected with either the PAR-2 cDNA or a construct made from the published PAR-2 genomic sequence responded with intracellular calcium mobilization to stimulation with 1 nM trypsin, 10 microM PAR-2-activating peptide (SLIGRL), or 1 microM thrombin receptor-activating peptide (SFLLRN). Untransfected cells responded only to stimulation with thrombin receptor activating peptide. Only transcripts corresponding to the PAR-2 cDNA could be detected in three mouse tissues examined.

A controlled long-term study of flunitrazepam, nitrazepam and placebo, with special regard to withdrawal effects

The hypnotic effect of flunitrazepam (Ro 5-4200), nitrazepam and a placebo was studied in 117 outpatients using hypnotics for at least 3 months prior to the study. They obtained various neurotropic drugs and this and other treatments were unchanged throughout the trial period of 13 weeks. This consisted of 3 weeks on the previously used hypnotic, 3 weeks on a test drug (during the first of these a doubling of the dose was permitted if the initial dose of 1 mg flunitrazepam, 5 mg nitrazepam or one tablet of placebo was not satisfactory) and 4 weeks' observation after a request to stop medication with the test drug. The effects were evaluated every week by self-ratings. Also noted were: the frequency of dose increase after 1 week of the test period, number of drop-outs in the test period, and failure in the attempt to stop taking the test drug. A "psychological concentration test" was done, as was a follow-up interview. The self-ratings had a good reliability and showed that more patients experienced shorter sleep induction, longer sleep time, better sleep quality and a subjective feeling of having had a better rest with flunitrazepam than with either nitrazepam or placebo. There were no differences between the nitrazepam and the placebo groups. Tiredness was the most common side effect and appeared in the same frequency in all groups. The number of patients who increased the dose after 1 week's medication, as well as the number of drop-outs, was significantly higher in the nitrazepam and placebo groups than in the flunitrazepam group. There was no difference in the ability to discontinue the medication between the test groups or between groups having previously used different hypnotics. The "psychological concentration test" did not reveal any differences between groups. It was concluded that withdrawal of a hypnotic in chronic users was not facilitated by the use of a placebo. This was interpreted as due to a strong psychological dependence upon the hypnotics and their lack of pharmacological effects during long-term treatment.