Oil crops for the future

Agriculture faces enormous challenges including the need to substantially increase productivity, reduce environmental footprint, and deliver renewable alternatives that are being addressed by developing new oil crops for the future. The efforts include domestication of Lepidium spp. using genomics-aided breeding as a cold hardy perennial high-yielding oil crop that provides substantial environmental benefits, expands the geography for oil crops, and improves farmers' economy. In addition, genetic engineering in Crambe abyssinica may lead to a dedicated industrial oil crop to replace fossil oil. Redirection of photosynthates from starch to oil in plant tubers and cereal endosperm also provides a path for enhancing oil production to meet the growing demands for food, fuel, and biomaterials. Insect pheromone components are produced in seed oil plants in a cost-effective and environmentally friendly pest management replacing synthetically produced pheromones. Autophagy is explored for increasing crop fitness and oil accumulation using genetic engineering in Arabidopsis.

High-Density Genetic Linkage Mapping of Lepidium Based on Genotyping-by-Sequencing SNPs and Segregating Contig Tag Haplotypes

Lepidium campestre has been targeted for domestication as future oilseed and catch crop. Three hundred eighty plants comprising genotypes of L. campestre, Lepidium heterophyllum, and their interspecific F2 mapping population were genotyped using genotyping by sequencing (GBS), and the generated polymorphic markers were used for the construction of high-density genetic linkage map. TASSEL-GBS, a reference genome-based pipeline, was used for this analysis using a draft L. campestre whole genome sequence. The analysis resulted in 120,438 biallelic single-nucleotide polymorphisms (SNPs) with minor allele frequency (MAF) above 0.01. The construction of genetic linkage map was conducted using MSTMap based on phased SNPs segregating in 1:2:1 ratio for the F2 individuals, followed by genetic mapping of segregating contig tag haplotypes as dominant markers against the linkage map. The final linkage map consisted of eight linkage groups (LGs) containing 2,330 SNP markers and spanned 881 Kosambi cM. Contigs (10,302) were genetically mapped to the eight LGs, which were assembled into pseudomolecules that covered a total of ∼120.6 Mbp. The final size of the pseudomolecules ranged from 9.4 Mbp (LG-4) to 20.4 Mpb (LG-7). The following major correspondence between the eight Lepidium LGs (LG-1 to LG-8) and the five Arabidopsis thaliana (At) chromosomes (Atx-1-Atx-5) was revealed through comparative genomics analysis: LG-1&2_Atx-1, LG-3_Atx-2&3, LG-4_Atx-2, LG-5_Atx-2&Atx-3, LG-6_Atx-4&5, LG-7_Atx-4, and LG-8_Atx-5. This analysis revealed that at least 66% of the sequences of the LGs showed high collinearity with At chromosomes. The sequence identity between the corresponding regions of the LGs and At chromosomes ranged from 80.6% (LG-6) to 86.4% (LG-8) with overall mean of 82.9%. The map positions on Lepidium LGs of the homologs of 24 genes that regulate various traits in A. thaliana were also identified. The eight LGs revealed in this study confirm the previously reported (1) haploid chromosome number of eight in L. campestre and L. heterophyllum and (2) chromosomal fusion, translocation, and inversion events during the evolution of n = 8 karyotype in ancestral species shared by Lepidium and Arabidopsis to n = 5 karyotype in A. thaliana. This study generated highly useful genomic tools and resources for Lepidium that can be used to accelerate its domestication.

Is out-of-hours cholecystectomy for acute cholecystitis associated with complications?

Background

Existing data on the safety of out-of-hours cholecystectomy are conflicting. The aim of this study was to investigate whether out-of-hours cholecystectomy for acute cholecystitis is associated with a higher risk for complications compared with surgery during office hours.

Methods

This was a population-based cohort study. The Swedish Gallstone Surgery and Endoscopic Retrograde Cholangiopancreatography Register (GallRiks) was used to investigate the association between out-of-hours cholecystectomy for acute cholecystitis and complications developing within 30 days. Data from patients who underwent cholecystectomy between 2006 and 2017 were collected. Out-of-hours surgery was defined as surgery commencing between 19.00 and 07.00 hours on weekdays, or any time at weekends (Friday 19.00 hours to Monday 07.00 hours). Multivariable logistic regression analysis was used to assess the risk of complications, with time of procedure as independent variable. The proportion of open procedures and proportion of procedures exceeding 120 min were also analysed. Adjustments were made for sex, age, ASA grade, time between admission and surgery, and hospital-specific features.

Results

Of 11 153 procedures included, complications occurred within 30 days in 1573 patients (14·1 per cent). The adjusted odds ratio (OR) for complications for out-of-hours versus office-hours surgery was 1·12 (95 per cent c.i. 0·99 to 1·28). The adjusted OR for procedures completed as open surgery was 1·39 (1·25 to 1·54), and that for operating time exceeding 120 min was 0·63 (0·58 to 0·69).

Conclusion

Out-of-hours complications may relate to patient factors and the higher proportion of open procedures.

Evaluation for epilepsy surgery - Why do patients not proceed to operation?

PURPOSE

To investigate the reasons for not proceeding to surgery in patients undergoing presurgical evaluation for epilepsy.

METHODS

A retrospective cohort study of 401 consecutive patients who were evaluated for but did not proceed to surgery for epilepsy between 1990 and 2016 at three Swedish epilepsy surgery centers was performed. Reasons for not proceeding to surgery were categorized as inconclusive investigation, seizure onset within eloquent cortex, evidence of multiple seizure foci, infrequent seizures, risk of postoperative severe cognitive decline, patient or caregiver declining surgery or invasive investigation, severe psychiatric or somatic comorbidity, patient death during evaluation and complications during the evaluation. Chi-square tests were performed to compare ordered categorical variables.

RESULTS

During the entire time period the main reasons for rejection were inconclusive investigation (34,4%) and multifocal seizure onset (20,0%). The risk for severe cognitive decline postoperatively was more often a cause for rejection in more recent years. Patients declining invasive EEG or surgery accounted for a minor but not insignificant proportion (14,2%) of rejections.

CONCLUSIONS

Inconclusive results from the presurgical evaluation and multifocal epilepsy were the main causes for not proceeding to surgery. The proportion of patients opting to abstain from surgery was low compared to other recent studies.

Methods to evaluate perspectives of safety, independence, activity, and participation in older persons using welfare technology. A systematic review

Purpose: To conduct a systematic review of existing methods to evaluate the individual aspects of welfare technology from the perspectives of independence, safety, activity, and participation. Furthermore, the study aimed to describe outcomes that have been the focus of previous research to evaluate individual aspects of welfare technology in older persons living in ordinary housing. Materials and methods: A systematic literature review in PubMed, CINAHL Plus, PsycINFO, Scopus, and Web of Science. Studies selected were those that explored the use of assistive and welfare technology devices from older persons' perspectives, and which considered the concepts of independence, safety, activity and participation, and quality of life. Results: A broad spectrum of instruments was applied in the studies. For independence, three questionnaires were used in the identified studies. For safety, one instrument was used in two versions. To study activity and participation as well as quality of life, several scales were used. Additionally, several studies included qualitative approaches for evaluation, such as interviews, or posed one or more questions regarding the effects of welfare technology. Conclusions: The integration of digital assistive and welfare technology should be based on the needs of older persons, and those needs must be assessed using reliable and relevant instruments. The heterogeneity of the target group, i.e., older persons, together with the fact that assessments must give consideration to identifying goals, obstacles, and risks as well as users' preferences, implies a person-centred approach.Implications for rehabilitationThe integration of digital assistive and welfare technology should be based on older persons' needs, and those needs must be assessed using reliable and relevant instruments.The heterogeneity of the target group, i.e. older persons, together with the fact that assessments must give consideration to identifying goals, obstacles and risks as well as users' preferences, implies a person-centred approach.The ideal would be one coherent model that explores the use of digital assistive and welfare technology from the individual, economic as well as organisational dimensions. This would cover the different needs and expectations of various stakeholders, including economic and organisational, but also the needs of the older person.

Identification of genes regulating traits targeted for domestication of field cress (Lepidium campestre) as a biennial and perennial oilseed crop

BACKGROUND

The changing climate and the desire to use renewable oil sources necessitate the development of new oilseed crops. Field cress (Lepidium campestre) is a species in the Brassicaceae family that has been targeted for domestication not only as an oilseed crop that produces seeds with a desirable industrial oil quality but also as a cover/catch crop that provides valuable ecosystem services. Lepidium is closely related to Arabidopsis and display significant proportions of syntenic regions in their genomes. Arabidopsis genes are among the most characterized genes in the plant kingdom and, hence, comparative genomics of Lepidium-Arabidopsis would facilitate the identification of Lepidium candidate genes regulating various desirable traits.

RESULTS

Homologues of 30 genes known to regulate vernalization, flowering time, pod shattering, oil content and quality in Arabidopsis were identified and partially characterized in Lepidium. Alignments of sequences representing field cress and two of its closely related perennial relatives: L. heterophyllum and L. hirtum revealed 243 polymorphic sites across the partial sequences of the 30 genes, of which 95 were within the predicted coding regions and 40 led to a change in amino acids of the target proteins. Within field cress, 34 polymorphic sites including nine non-synonymous substitutions were identified. The phylogenetic analysis of the data revealed that field cress is more closely related to L. heterophyllum than to L. hirtum.

CONCLUSIONS

There is significant variation within and among Lepidium species within partial sequences of the 30 genes known to regulate traits targeted in the present study. The variation within these genes are potentially useful to speed-up the process of domesticating field cress as future oil crop. The phylogenetic relationship between the Lepidium species revealed in this study does not only shed some light on Lepidium genome evolution but also provides important information to develop efficient schemes for interspecific hybridization between different Lepidium species as part of the domestication efforts.

'"For a better life …" A study on migration and health in Nicaragua'

BACKGROUND

Nicaraguans have migrated internally and internationally for centuries due to economic, political and sociocultural factors. Deficiencies in the country's health care system have produced inequities in people's access to health care and medicines. Remittances have become an important source of income, partly invested in health.

OBJECTIVES

The overall aim of the study was to analyse migration-health relations in contemporary Nicaragua within a broader context of socio-economic transformations.

METHODS

The study uses a mixed-methods approach, combining qualitative interview data and quantitative survey data.

RESULTS

The findings show that migration is commonly practised as a strategy for making a living and is related to the struggle for a better life. Health concerns are indirectly embedded in people's mobile livelihoods, but also directly influence migration motives. Furthermore, migration involves both advantages and disadvantages for health. Physical and sexual violence can come to an end for migrating women, health care and medicine can become more accessible for internal migrants, and vulnerabilities caused by environmental disasters can be avoided by moving. Moreover, remittances can improve people's everyday life and health. Yet migration can also be a stressful and health-damaging event. International migrants, particularly the undocumented, can have problems accessing health care, and also experience much danger at border crossings. Transnational families can suffer emotionally as well as physically due to separation. Findings from the survey show that family members of migrants do not rate their physical health as good as often as non-migrating families.

CONCLUSIONS

The Nicaraguan population is not guaranteed its social rights of citizenship. This results in mobile livelihoods and the need for translocal social support (e.g. remittances). Migration can have both positive and negative effects on health for migrants and their family members; geographical distance and social differences are key to the outcome.

Daily life consequences, cognitive impairment, and fatigue after transient ischemic attack

OBJECTIVES

Studies suggest that fatigue and cognitive impairment may be present after transient ischemic attack (TIA), but little is known about consequences in daily life. The main aim was to longitudinally explore the presence of fatigue, cognitive impairment, and consequences in daily life including communication after clinically diagnosed TIA at 1 and 9 months after the event.

MATERIAL AND METHODS

A consecutive sample of 46 patients (23 women, 69 ± 12.3 years) was assessed at discharge from hospital and at 1 and 9 months after TIA regarding cognition, mental fatigue, tiredness, and activities of daily life. This served as basis for an interview concerning experienced changes related to the TIA.

RESULTS

Problems in daily life with probable association with the TIA were experienced by 37% (n = 45) of participants 9 months after the TIA event. Cognitive impairment was present in 40% (n = 44) after 1 month and 30% (n = 23) after 9 months. Mental fatigue was experienced by 26% (n = 42) after 1 month and 17% (n = 39) after 9 months. Communication problems were reported and increased from 7 to 14 participants between the two time points.

CONCLUSIONS

A third of the TIA patients experienced problems in performance of complex activities in daily life and often communication problems within the first 9 months. Cognitive impairment and mental fatigue could be factors influencing performance in daily life and at work, but this needs to be verified in a larger sample. The risk of activity limitations indicates need for multiprofessional support and systematic routines for TIA follow-up.

Androgen Treatment of Abdominally Obese Men

Middle-aged men with abdominal obesity were treated in a double-blind study with moderate doses of transdermal preparations of testosterone (T), dihydrotestosterone (DHT), or placebo. This resulted in moderately elevated T concentrations and marked decreases in follicle stimulating and luteinizing hormones in the group treated with T, while the DHT group showed elevated DHT, markedly lower T values, and less diminution of gonadotropin concentrations. In the group treated with T visceral fat mass decreased (measured by computerized tomography) without significant changes in other depot fat regions. Lean body mass did not change. In the group treated with T, glucose disposal rate, measured with the euglycemic hyperinsulinemic clamp method, was markedly augmented. Plasma triglycerides, cholesterol, and fasting blood glucose concentrations as well as diastolic blood pressure decreased. There were no such changes in the DHT or placebo treatment groups. The men treated with T reported increased well-being and energy. In none of the groups did prostate volume, specific prostate antigen concentration, genito-urinary history, or urinary flow measurement change. It is suggested that supplementation of abdominal obese men with moderate doses of T might have several beneficial effects.

Growth Hormone Secretion after Testosterone Administration to Men with Visceral Obesity

Visceral obesity in men has been reported to be characterized by low testosterone (T) and insulin-like growth factor I (IGF-I) concentrations, the latter suggesting a relative growth hormone (GH) deficiency. Since T and GH-secretions are interrelated, men with visceral obesity were substituted with T for 14 days, and diurnal secretion pattern of GH as well as IGF-I concentrations, and metabolic variables were followed. Visceral obese men were characterized by a decreased total GH secretion and diminished peak amplitude, size, and number. T-substitution was followed by elevation of IGF-I levels. The IGF-I increase correlated with the elevation of T-concentration, and was most pronounced in men with the lowest concentrations of free T from the outset. There were no detectable changes in total quantity, amplitude, size or number of peaks of GH secretion. Glucose, chlolesterol and triglycerides as well as diastolic blood pressure decreased. There were no changes in thyroid or hematology variables. T-substitution of visceral obese men is followed by an elevation of IGF-I concentrations. It is suggested that this might be due either to minor, non-detectable increases in GH secretion, or to direct effects of T on IGF-I concentrations. The regulatory mechanisms by which T-administration are leading to metabolic and anthropometric improvements, might be direct effects of T, with or without mediation via GH secretion.

Rap1 binds single-stranded DNA at telomeric double- and single-stranded junctions and competes with Cdc13 protein

The ends of eukaryotic chromosomes are protected by specialized telomere chromatin structures. Rap1 and Cdc13 are essential for the formation of functional telomere chromatin in budding yeast by binding to the double-stranded part and the single-stranded 3' overhang, respectively. We analyzed the binding properties of Saccharomyces castellii Rap1 and Cdc13 to partially single-stranded oligonucleotides, mimicking the junction of the double- and single-stranded DNA (ds-ss junction) at telomeres. We determined the optimal and the minimal DNA setup for a simultaneous binding of Rap1 and Cdc13 at the ds-ss junction. Remarkably, Rap1 is able to bind to a partially single-stranded binding site spanning the ds-ss junction. The binding over the ds-ss junction is anchored in a single double-stranded hemi-site and is stabilized by a sequence-independent interaction of Rap1 with the single-stranded 3' overhang. Thus, Rap1 is able to switch between a sequence-specific and a nonspecific binding mode of one hemi-site. At a ds-ss junction configuration where the two binding sites partially overlap, Rap1 and Cdc13 are competing for the binding. These results shed light on the end protection mechanisms and suggest that Rap1 and Cdc13 act together to ensure the protection of both the 3' and the 5' DNA ends at telomeres.

Single- and double-stranded DNA binding proteins act in concert to conserve a telomeric DNA core sequence

BACKGROUND

Telomeres are protective cap structures at the ends of the linear eukaryotic chromosomes, which provide stability to the genome by shielding from degradation and chromosome fusions. The cap consists of telomere-specific proteins binding to the respective single- and double-stranded parts of the telomeric sequence. In addition to the nucleation of the chromatin structure the telomere-binding proteins are involved in the regulation of the telomere length. However, the telomeric sequences are highly diverged among yeast species. During the evolution this high rate of divergency presents a challenge for the sequence recognition of the telomere-binding proteins.

RESULTS

We found that the Saccharomyces castellii protein Rap1, a negative regulator of telomere length, binds a 12-mer minimal binding site (MBS) within the double-stranded telomeric DNA. The sequence specificity is dependent on the interaction with two 5 nucleotide motifs, having a 6 nucleotide centre-to-centre spacing. The isolated DNA-binding domain binds the same MBS and retains the same motif binding characteristics as the full-length Rap1 protein. However, it shows some deviations in the degree of sequence-specific dependence in some nucleotide positions. Intriguingly, the positions of most importance for the sequence-specific binding of the full-length Rap1 protein coincide with 3 of the 4 nucleotides utilized by the 3' overhang binding protein Cdc13. These nucleotides are very well conserved within the otherwise highly divergent telomeric sequences of yeasts.

CONCLUSIONS

Rap1 and Cdc13 are two very distinct types of DNA-binding proteins with highly separate functions. They interact with the double-stranded vs. the single-stranded telomeric DNA via significantly different types of DNA-binding domain structures. However, we show that they are dependent on coinciding nucleotide positions for their sequence-specific binding to telomeric sequences. Thus, we conclude that during the molecular evolution they act together to preserve a core sequence of the telomeric DNA.

Sequence analysis of human rhinovirus aspirated from the nasopharynx of patients with relapsing-remitting MS

BACKGROUND

Upper respiratory infections were reported to trigger multiple sclerosis relapses. A relationship between picornavirus infections and MS relapses was recently reported.

OBJECTIVE

To evaluate whether human rhinovirus is associated with multiple sclerosis relapses and whether any particular strain is predominant.

METHOD

Nasopharyngeal fluid was aspirated from 36 multiple sclerosis patients at pre-defined critical time points. Reverse-transcriptase-PCR was performed to detect human rhinovirus-RNA. Positive amplicons were sequenced.

RESULTS

We found that rhinovirus RNA was present in 17/40 (43%) of specimens obtained at the onset of a URTI in 19 patients, in 1/21 specimens during convalescence after URTI in 14 patients, in 0/6 specimens obtained in 5 patients on average a week after the onset of an "at risk" relapse, occurring within a window in time from one week before to three weeks after an infection, and in 0/17 specimens obtained after the onset of a "not at risk" relapse not associated with any infection in 12 patients. Fifteen specimens from healthy control persons not associated with URTI were negative. The frequency of HRV presence in URTI was similar to that reported for community infections. Eight amplicons from patients represented 5 different HRV strains.

CONCLUSION

We were unable to reproduce previous findings of association between HRV infections and multiple sclerosis relapses. HRV was not present in nasopharyngeal aspirates obtained during "at risk" or "not at risk" relapses. Sequencing of HRV obtained from patients during URTI did not reveal any strain with predominance in multiple sclerosis.

Genetic variant of the human homologous recombination-associated gene RMI1 (S455N) impacts the risk of AML/MDS and malignant melanoma

The newly identified protein BLAP75/RMI1 associates with the helicase BLM and is critical for the function of the homologous recombination complex. Mutations altering BLM function are associated with highly elevated cancer susceptibility (Bloom's syndrome). We have analyzed the common polymorphism Ser455Asn in RMI1 and its association with cancer risk in acute myeloid leukemia (AML, N=93), myelodysplatic syndromes (MDS, N=74), and malignant melanoma (MM, N=166). Two control groups were used: one population-based (N=119) and one recruited from spouses of cancer patients (N=189). The results showed a consistent pattern, where carriers of the Asn variant had a significantly increased risk of AML/MDS. The risk of AML/MDS for SerAsn+AsnAsn subjects was odds ratio (OR)=1.7, 95% confidence interval (CI) 1.1-2.5 or MM was OR=1.5, 95% CI 1.0-2.2. Age might modify the effect of RMI1 on cancer risk. This was most evident for MM: AsnAsn homozygotes > or =64 years showed OR=2.7, 95% CI 1.1-6.0, whereas individuals <64 years showed OR=0.87, 95% CI 0.31-2.5. These results indicate a role of low-penetrance genes involved in BLM-associated homologous recombination for cancer risk.

Cytokine secretion in decidual mononuclear cells from term human pregnancy with or without labour: ELISPOT detection of IFN-gamma, IL-4, IL-10, TGF-beta and TNF-alpha

Cytokines are believed to be important in maintaining pregnancy and in the process of labour induction in humans. The aim of this study was to investigate the secretion of the cytokines interferon-gamma (IFN-gamma), interleukin-4 (IL-4), IL-10, transforming growth factor-beta (TGF-beta) and tumour necrosis factor-alpha (TNF-alpha) in decidual tissue with or without labour. Decidual tissue was collected from 32 healthy women undergoing elective caesarean sections before the onset of labour (n=17) or after normal vaginal delivery (n=15). Mononuclear cells were analysed for cytokine secretion with ELISPOT. To validate the widely used method of tissue collected at caesarean sections and after vaginal deliveries as a representative of before and after labour, respectively, placenta biopsies were collected from 12 healthy women to study the expression of the prostaglandin pathway enzymes cyclooxygenase-2 (COX-2) and microsomal prostaglandin E(2) synthase (mPGES). Decidual mononuclear cells from term human pregnancy spontaneously secrete IFN-gamma, IL-4, IL-10, TGF-beta and TNF-alpha. No difference was seen in cytokine secretion with or without labour, indicating that decidual leukocytes are not the main cell population responsible for plausible cytokine regulation in the process of termination of pregnancy. Placental tissues obtained after vaginal delivery showed a higher mRNA expression of the prostaglandin regulating molecules COX-2 and mPGES than tissues from caesarean sections before the onset of labour, validating that the model can be used as a representative of the state before and after labour.

Psychometric evaluation of a Swedish version of the Reiss Screen for Maladaptive Behavior

BACKGROUND

People with intellectual disability (ID) are afflicted by mental health problems to a greater extent than other individuals, and the coexistence of ID and mental health problems involves diagnostic as well as treatment difficulties.

METHODS

A Swedish version of the Reiss Screen for Maladaptive Behavior (RSMB), an instrument used for identification of mental health problems in people with intellectual disability (ID) was evaluated in terms of inter-rater agreement, internal consistency, item grouping and criterion validity based on a random sample and a clinical group of adults with ID.

RESULTS

The Swedish version of the RSMB had moderate-to-low inter-rater agreement on specific items and good internal consistency. The total score was considered to be a fairly reliable measure of a positive or negative result on the RSMB. A principal component analysis yielded seven interpretable components. A close resemblance in sets of items between the Swedish version and the original version of RSMB was found for three subscales: Aggressive Behaviour, Avoidance Disorder and Depression (Behavioural Signs). The outcome of the criterion validity analysis indicated a higher rate of false negatives than false positives.

CONCLUSIONS

The potential influence of concurrent psychopharmacological treatment is discussed. It is concluded that the Swedish version of the RSMB can be used as intended by staff as a primary screening device for the identification of mental health problems among people with ID in a Swedish setting.

Reliability and responsiveness of three different pain assessments

The visual analogue scale (VAS) and ordered categorical scales, i.e. numeric rating scales (NRS), are commonly used in the assessment of pain. However, these scales are bounded by fixed endpoints and thus the range of measurement is limited. The disparity in repeated assessments of perceived pain intensity with the VAS, NRS, and electrical stimulation applied as a matching stimulus was studied in 69 patients (48 women and 21 men, 19-72 years) with chronic nociceptive or neurogenic pain. Responsiveness with transcutaneous electrical nerve stimulation (TENS) using the same measurement procedures was evaluated in the same patients. Comparison of results from the three pain assessments showed that the painmatcher is at least as reliable and responsive as VAS and NRS. None of the three measurements showed evidence for systematic disagreement and had only significant random individual disagreement. They also showed evidence for responsiveness.

Effects of reduced oxygen partial pressure on cognitive performance in confined spaces

The reduction of oxygen levels is a technique used both for fire fighting and fire protection in confined spaces. The purpose of this study was to find out if and how reduced oxygen levels affect cognitive performance in a small group of persons living in a confined space such as a submarine. In 3 separate experiments lasting for 11 to 14 days, a total of 22 men were exposed to normoxic and different levels of hypoxic normobaric atmospheres (15, 14, and 13 kPa O2). Each participant completed a cognitive test battery twice every 24-hr period in the first 2 experiments, but only once a day in the 3rd experiment. Performance in almost all tests improved with the number of test sessions performed, despite reductions of the oxygen partial pressure. Under the conditions tested, cognitive performance decrements could not be observed if inspiratory oxygen partial pressure was kept above 13 kPa.

Exploration of sequence space for protein engineering

The process of protein engineering is currently evolving towards a heuristic understanding of the sequence-function relationship. Improved DNA sequencing capacity, efficient protein function characterization and improved quality of data points in conjunction with well-established statistical tools from other industries are changing the protein engineering field. Algorithms capturing the heuristic sequence-function relationships will have a drastic impact on the field of protein engineering. In this review, several alternative approaches to quantitatively assess sequence space are discussed and the relatively few examples of wet-lab validation of statistical sequence-function characterization/correlation are described.

Directed evolution: the 'rational' basis for 'irrational' design

The development of powerful genetic manipulation formats has revolutionized the creation of functional biological molecules. Recent advances in directed evolution demonstrate that multiple properties of proteins can be optimized simultaneously and rapidly. Improved proteins often contain multiple and dispersed substitutions that act synergistically to improve enzyme properties and function. The benefits of such multiple changes are often not predictable from a priori structural knowledge. Furthermore, alternative solutions to gaining functional change can be obtained.

Cellulose powder from Cladophora sp. algae

The surface are and crystallinity was measured on a cellulose powder made from Cladophora sp. algae. The algae cellulose powder was found to have a very high surface area (63.4 m2/g, N2 gas adsorption) and build up of cellulose with a high crystallinity (approximately 100%, solid state NMR). The high surface area was confirmed by calculations from atomic force microscope imaging of microfibrils from Cladophora sp. algae.

Characterisation of particle properties and compaction behaviour of hydroxypropyl methylcellulose with different degrees of methoxy/hydroxypropyl substitution

The particle characteristics and compaction behaviour of hydroxypropyl methylcellulose (HPMC) powders from two different suppliers were studied regarding effects of methoxy/hydroxypropyl substitution. Samples included Methocel K4M (low substitution ratio), E4M (medium) and F4M (high) and the corresponding substitution ratios from Metolose: 90 SH 4000, 60 SH 4000, and 65 SH 4000. Characterisation of the particle properties and compaction behaviour of the pure polymers suggested that reported differences in drug release behaviour of Methocel E4M compared with the other two powders may be related to the lower powder surface area, differing particle morphology and lower fragmentation propensity during compaction. In addition, compacts of Methocel E4M were weaker when tested in both axial and radial directions and had different porosity and elastic recovery properties. There were no differences between the polymers in degree of disorder, as evaluated by solid-state nuclear magnetic resonance spectroscopy. The different behaviour of Methocel E4M could, however, be related to the overall higher total degree of substitution of this polymer and in particular the high content of methoxy groups compared to the other polymers. The methoxy substituent is hydrophobic and may, when present in sufficiently high concentrations, change the particulate and mechanical properties of the powder, thus potentially affecting the compactability. The high content of methoxy groups might also decrease the development of inter- and intraparticulate hydrogen bonds during compaction, and suppress the actions of the hydrophilic hydroxypropyl groups, both of which could affect drug release.

Use of tablet tensile strength adjusted for surface area and mean interparticulate distance to evaluate dominating bonding mechanisms

In this study, tablet tensile strength has been adjusted for tablet surface area and the average distance between particles in compacts of different materials. The aim of the study was to evaluate the feasibility of using this concept to assess the dominating interparticulate bonding mechanisms. Adjustment of the tensile strength for both tablet surface area and mean pore radius gave similar bonding strength values for materials bonding mainly by weak distance forces (crystalline lactose, sucrose, and microcrystalline cellulose) almost independently of compaction pressure. However, particle size and other factors may still affect the compensated strength values. The bond strength was much higher and more varied for materials bonding also with solid bridges (potassium chloride, sodium chloride, and possibly also sodium bicarbonate and amorphous lactose). For these materials, particle size and compaction pressure had a substantial effect on the bond strength. It is probably the formation of continuous bridges between adjacent particles that is important in these materials rather than the surface properties and the average distance between particles positioned at some distance from each other. Hence, adjusting the tensile strength of compacts does not necessarily reflect all the dominating factors responsible for interparticulate bonding. Nonetheless, adjustment for tablet surface area and mean pore radius allowed discrimination between different dominating interparticulate bonding mechanisms in these compacted materials.

Identification of the 16S rRNA m5C967 methyltransferase from Escherichia coli

The fmu gene product has been proposed to be an RNA methyltransferase [Koonin, E. V. (1994) Nucleic Acids Res. 22, 2476-2478]. Fmu has been cloned and expressed, and the encoded 47 kDa protein has been purified and characterized. The enzyme catalyzed specific methylation of C967 of unmodified 16S rRNA transcripts. A 16mer stem-loop structure containing C967 (nt 960-975) was also a good substrate for the enzyme in vitro. Methylation of C967 was confirmed by several methods including analysis of RNase T1 digests and nearest-neighbor analysis. Fmu did not catalyze methylation of transcripts of 23S rRNA. E. coli cells that contained kanr-disrupted fmu produced 16S rRNA that could be specifically methylated by Fmu in vitro at C967 but not C1407. Further, fmu disruption did not significantly alter the growth rate of E. coli in rich or minimal media. We propose renaming this ORF "rrmB" and the enzyme "RrmB" for rRNA methyltransferase.

Multiple genetic modifications of the erythromycin polyketide synthase to produce a library of novel "unnatural" natural products

The structures of complex polyketide natural products, such as erythromycin, are programmed by multifunctional polyketide synthases (PKSs) that contain modular arrangements of functional domains. The colinearity between the activities of modular PKS domains and structure of the polyketide product portends the generation of novel organic compounds-"unnatural" natural products-by genetic manipulation. We have engineered the erythromycin polyketide synthase genes to effect combinatorial alterations of catalytic activities in the biosynthetic pathway, generating a library of >50 macrolides that would be impractical to produce by chemical methods. The library includes examples of analogs with one, two, and three altered carbon centers of the polyketide products. The manipulation of multiple biosynthetic steps in a PKS is an important milestone toward the goal of producing large libraries of unnatural natural products for biological and pharmaceutical applications.

Identification of the rrmA gene encoding the 23S rRNA m1G745 methyltransferase in Escherichia coli and characterization of an m1G745-deficient mutant

An Escherichia coli mutant lacking the modified nucleotide m1G in rRNA has previously been isolated (G. R. Björk and L. A. Isaksson, J. Mol. Biol. 51:83-100, 1970). In this study, we localize the position of the m1G to nucleotide 745 in 23S rRNA and characterize a mutant deficient in this modification. This mutant shows a 40% decreased growth rate in rich media, a drastic reduction in loosely coupled ribosomes, a 20% decreased polypeptide chain elongation rate, and increased resistance to the ribosome binding antibiotic viomycin. The rrmA gene encoding 23S rRNA m1G745 methyltransferase was mapped to bp 1904000 on the E. coli chromosome and identified to be identical to the previously sequenced gene yebH.

The prevalence of people with intellectual disability admitted to general hospital psychiatric units: level of handicap, psychiatric diagnoses and care utilization

Previous studies have stated that people with intellectual disability (ID) are more often afflicted by psychiatric disorders than the general population. In spite of the high prevalence of psychiatric disorders among people with ID, it is not known how many actually receive psychiatric in-patient care and treatment by the mental health services. In the present study, the number of people with mild and severe ID admitted to in-patient psychiatric care were compared with corresponding figures in the general population in Sweden. The results show a low frequency of psychiatric care utilization among people with ID and coexisting psychiatric disorders in comparison to the proportion of psychiatric care utilization among people with psychiatric disorders in the general population. The results are discussed in terms of how the level of ID might influence referral or diagnoses, the length of admissions, and the support provided within the special services to people with ID and psychiatric disorders.

Effects of normobaric hypoxic confinement on visual and motor performance

INTRODUCTION

The use of reduced oxygen levels has been suggested for fire prevention in closed spaces, such as submarines. However, if humans are to work and live in environments with reduced oxygen levels, the effect of hypoxia on human performance must be further assessed.

METHODS

In 3, 11- to 14-d confinements a total of 22 subjects were exposed to different levels of normobaric hypoxia (13, 14, and 15 kPa O2), for up to 10 d, with intervening periods of normoxia. In each experiment eight subjects were divided into two teams, working in 6-h shifts around the clock. Subjects performed tests of spatial orientation, visual reaction time, parallel processing and motor skills. Performance tests and questionnaires were administered once or twice in every 24-h period.

RESULTS

All of the subjects appeared to tolerate the acute reduction in oxygen partial pressure well. In many of the tests performance improved with time as a result of learning, despite reductions in the oxygen level. No reduction in performance or decrease in rate of learning was observed at any of the oxygen levels tested.

CONCLUSIONS

Oxygen levels down to 14 kPa appear not to impair visual and motor performance during rest.

The spoU gene of Escherichia coli, the fourth gene of the spoT operon, is essential for tRNA (Gm18) 2'-O-methyltransferase activity

We have evidence that the open reading frame previously denoted spoU is necessary for tRNA (Gm18) 2'-O-methyltransferase activity. The spoU gene is located in the gmk-rpoZ-spoT-spoU-recG operon at 82 minutes on the Escherichia coli chromosome. The deduced amino acid sequence of spoU shows strong similarities to previously characterized 2'-O-methyltransferases. Comparison of the nucleoside modification pattern of hydrolyzed tRNA, 16S rRNA and 23S rRNA from wild-type and spoU null mutants showed that the modified nucleoside 2'-O-methylguanosine (Gm), present in a subset of E. coli tRNAs at residue 18, is completely absent in the spoU mutant, suggesting that spoU encodes tRNA (Gm18) 2'-O-methyltransferase. Nucleoside modification of 16S and 23S rRNA was unaffected in the spoU mutant. Insertions in the downstream recG gene did not affect RNA modification. Absence of Gm18 in tRNA does not influence growth rate under the tested conditions and does not interfere with activity of the SupF amber suppressor, a suppressor tRNA that normally has the Gm18 modification. We suggest that the spoU gene be renamed trmH (tRNA methylation).

Identification of new RNA modifying enzymes by iterative genome search using known modifying enzymes as probes

The complete nucleotide sequences of the Haemophilus influenzae and Mycoplasma genitalium genomes and the partially sequenced Escherichia coli chromosome were analyzed to identify open reading frames (ORFs) likely to encode RNA modifying enzymes. The protein sequences of known RNA modifying enzymes from three families--m5U methyltransferases, psi synthases and 2'-O methyltransferases--were used as probes to search sequence databases for homologs. ORFs identified as homologous to the initial probes were retrieved and used as new probes against the databases in an iterative manner until no more homologous ORFs could be identified. Using this approach, we have identified two new m5U methyltransferases, seven new psi synthases and four new 2'-O methyltransferases in E. coli. Many of the ORFs found in E.coli have direct genetic counterparts (orthologs) in one or both of H.influenzae and M.genitalium. Since there is a near-complete knowledge of RNA modifications in E.coli, functional activities of the proteins encoded by the identified ORFs were proposed based on the level of conservation of the ORFs and the modified nucleotides.

Isolation of genes encoding tRNA binding proteins by probing an expression library with unmodified tRNA

A rapid method for isolating Escherichia coli genes encoding proteins which bind unmodified, but not modified, tRNA is described. The method is generally applicable, and can be used to clone many RNA binding proteins where a structured RNA ligand is known.

Validation of four scales for the acute stage of stroke

OBJECTIVES

To validate whether a simplified scale for the acute stage of stroke--the Scandinavian Stroke Supervision scale--is sufficient for monitoring symptom progression of prognostic importance.

DESIGN

The capacity of the scale was compared to that of the Mathew, Toronto and Fugl-Meyer stroke scales and the Barthel ADL index.

SETTING

The stroke unit of Danderyd Hospital, which cares for a defined population.

SUBJECTS

Fifty noncomatose patients with objectively recorded symptoms at entry were examined over a period of 5 days by one physician (250 ratings/scale). The last 10 patients were also investigated by another doctor in the same manner (50 ratings/scale) and by nurses (50 ratings) the Scandinavian scale only. The amount of time required by each scale was tested in another 10 patients by two nurses (100 ratings/scale).

INTERVENTIONS

Routine investigation and treatment.

MAIN OUTCOME MEASURES

The reliability, validity, time requirement and correlation of the scales were evaluated, as was their ability to reveal progress of symptoms.

RESULTS

All scales were highly significantly correlated. The interobserver agreement was excellent between the physicians but not as good between the physician and the nurses. The prediction of the outcome at discharge and after 3 months was very satisfactory for all of the scales with regard to the whole groups of patients, but none of them could predict the outcome for an individual with certainty. The Scandinavian Stroke Supervision scale was least time consuming, and had the fewest uncertainties expressed by the testers. This scale recorded the progression of slightly fewer symptoms, but did record those with a more serious impact on patient outcome.

CONCLUSION

The time-saving, simplified Scandinavian scale was as reliable and as valid as the other scales, and detected deterioration that was important for patient outcome as satisfactorily as the other scales.

Production of large amounts of recombinant interleukins by cDNA transfected mouse myeloma cells cultured in dialysis tubing

Studies of interleukin function often require large quantities of these highly expensive substances. The available interleukins are generally recombinant proteins produced in bacteria or yeast and, less commonly, interleukins produced by mammalian cells, which provide appropriate glycosylation and other post-translational modifications. Due to differences in biosynthesis, difficulties in production and purification the quality of the interleukin preparations may vary. We have taken advantage of the recently developed constitutively interleukin-secreting mouse myeloma cell lines and the dialysis tubing culture technique, which permit cells to be grown at high densities, in order to establish a method for the production of large amounts of recombinant murine IL-2 and IL-4. We show that these interleukins can be produced at low cost and in concentrations 20-30-fold higher than in conventional culture flasks. A single dialysis tubing culture will produce more than 10(6) U of interleukin which may be compared with the available commercial preparations containing between 10- and a 100-fold less per vial. The IL-2 and IL-4 produced in this manner are biologically active molecules as demonstrated by the strong proliferative response of clonal T cells and the isotype-switching effect in LPS-stimulated splenic B cell cultures. The dialysis tubing culture technique is a simple and highly cost-effective means of generating large quantities of biologically active interleukins and is especially suitable for research laboratories interested in functional studies of these proteins.

Effects of acute exercise on insulin and non-insulin-dependent glucose uptake in normal and moderately obese women

OBJECTIVES

To investigate the effectiveness of exercise on the regulation of insulin sensitivity.

METHODS

Eleven premenopausal women, with body fat mass from the normal range to moderate obesity, were examined with glucose clamp at 10 mmol/L glucose concentration to determine insulin-dependent and non-insulin-dependent (after somatostatin inhibition of endogenous insulin production) glucose uptake (= IDGU and NIDGU respectively) before and 24 hrs after a glycogen-decreasing exercise.

RESULTS

IDGU, but not NIDGU, increased after exercise. The degree of increase of IDGU after exercise showed negative correlations with body mass index (borderline, significance), the waist to hip circumference ratio, fasting free testosterone and free fatty acid concentrations, as well as diastolic blood pressure (borderline significance), and a positive relationship to sex hormone binding globulin concentration and IDGU before exercise.

CONCLUSION

It is concluded that only IDGU contributes to the augmentation of insulin sensitivity after a glycogen-decreasing exercise in women. Additionally, the increase of IDGU is less in abdominal obesity, and negatively dependent on free fatty acid concentrations, hyperandrogenism and hyperinsulinaemia, all putative pathogenetic factors for insulin resistance.

Quantitative sequence-activity models (QSAM)--tools for sequence design

Models have been developed that allow the biological activity of a DNA segment to be altered in a desired direction. Partial least squares projections to latent structures (PLS) was used to establish a quantitative model between a numerical description of 68 bp fragments of 25 E.coli promoters and their corresponding quantitative measure of in vivo strength. This quantitative sequence-activity model (QSAM) was used to generate two 68 bp fragments predicted to be more potent promoters than any of those on which the model originally was based. The optimized structures were experimentally verified to be strong promoters in vivo.

The tRNA-(m5U54)-methyltransferase of Escherichia coli is present in two forms in vivo, one of which is present as bound to tRNA and to a 3'-end fragment of 16 S rRNA

The enzyme tRNA-(m5U54)-methyltransferase (EC 2.1.1.35) of Escherichia coli catalyzes the transfer of a methyl group from S-adenosyl-L-methionine to uridine in position 54 of the T psi-loop of all E. coli tRNA species, forming 5-methyluridine (m5U). In vivo, this enzyme is present both as a native polypeptide of 42 kDa and as a TrmA.RNA complex. The TrmA.RNA complex is not dissociated during strong denaturing conditions such as boiling in 8 M urea or 6 M guanidine HCl, consisting with that the RNA is covalently bound to the protein. After sequencing and Southern blot analyses, the RNA was identified to be a subset of undermodified tRNA species as well as the 3' terminus of 16 S rRNA. However, the complex is not associated with the ribosome and the covalently bound RNA does not affect the tRNA methylating activity of the enzyme.

Cost effectiveness of primary stroke prevention in atrial fibrillation: Swedish national perspective

OBJECTIVE

To assess the potential effects of primary prevention with anticoagulants or aspirin in atrial fibrillation on Swedish population.

DESIGN

Analysis of cost effectiveness based on the following assumptions: about 83,000 people have atrial fibrillation in Sweden, of whom 22,000 would be potential candidates for treatment with anticoagulants and 55,000 for aspirin treatment; the annual 5% stroke rate is reduced by 64% (with anticoagulants) and 25% (with aspirin); incidence of intracranial haemorrhage of 0.3%, 1.3%, or 2.0% per year; direct and indirect costs of a stroke of Kr180,000 and Kr90,000; estimated annual cost of treatment is Kr5030 for anticoagulants and Kr100 for aspirin.

SETTING

Total Swedish population.

MAIN OUTCOME MEASURES

Direct and indirect costs of stroke saved, number of strokes prevented, and cost of preventive treatment.

RESULTS

Depending on the rate of haemorrhagic complications 34 to 83 patients would need to be treated annually with anticoagulants to prevent one stroke; 83 patients would need to be treated with aspirin. Giving anticoagulant treatment only would reduce costs by Kr60 million if the incidence of intracranial haemorrhage were 0.3% but would imply a net expense if the complication rate exceeded 1.3%. The total savings from giving anticoagulant (22,000 patients) and aspirin (55,000 patients) treatment would be Kr175 million per year corresponding to 2 million pounds per million inhabitants each year.

CONCLUSIONS

Treatment with anticoagulants and, if contraindications exist, with aspirin is cost effective provided that the risk of serious haemorrhage complications due to anticoagulants is kept low.

Physical map of the oxyR-trmA region (minute 89.3) of the Escherichia coli chromosome

Images

The gene for a tRNA modifying enzyme, m5U54-methyltransferase, is essential for viability in Escherichia coli

One of the most abundant modified nucleosides in tRNA is 5-methyluridine (m5U or rT, ribothymidine). The enzyme tRNA(m5U54)methyltransferase [S-adenosyl-L-methionine:tRNA (uracil-5-)-methyltransferase, EC 2.1.1.35] (the trmA gene product) catalyzes S-adenosylmethionine-dependent methylation of the uracil in position 54 (T psi C loop) in all Escherichia coli tRNAs to form m5U. Hitherto no modified nucleoside in tRNA has been shown to be essential for growth, although their importance in fine tuning the function of tRNA is well established. In this paper, we show that the structural gene trmA is essential for viability, although the known catalytic activity of the tRNA(m5U54)methyltransferase is not.

Echocardiographic findings and the increased risk of stroke in nonvalvular atrial fibrillation

We studied whether cardiac abnormalities contribute to the increased risk of stroke in patients with nonvalvular atrial fibrillation (NVAF). M-mode and 2D echocardiography were performed in four age- and gender-matched groups: 20 stroke patients with NVAF, 20 patients with NVAF who had not suffered a previous stroke, 20 stroke patients with sinus rhythm, and 40 healthy controls. Their mean age was 77 years. The two groups with atrial fibrillation differed from healthy controls in that they had more 2D-echocardiographic findings of severe left-ventricular-wall-motion abnormalities (p < 0.05) and tended more often to have enlarged left ventricles, and hypertrophic and congestive cardiomyopathy. Left atrial diameter was 47 mm compared to 41 and 39 mm in the two groups with sinus rhythm (p < 0.001). Intracardiac thrombi were only found in the two atrial-fibrillation groups (with stroke: 15% without stroke: 5%). Aortic sclerosis was common in all groups (30-60%), as was mitral annulus calcification (10-20%). The only significant difference between the two atrial-fibrillation groups was a higher frequency of earlier ischemic heart disease in the stroke group. Both atrial-fibrillation groups had cardiac abnormalities predisposing for embolic as well as thrombotic stroke.