A Gradual Transition Toward Anaplasia in Wilms Tumor Through Tolerance to Genetic Damage

Patients with Wilms tumor (WT) in general have excellent survival, but the prognosis of patients belonging to the subgroup of WT with diffuse anaplasia (DA) is poor due to frequent resistance to chemotherapy. We hypothesized that DA WT cells might undergo changes, such as acquiring a persistent tolerance to DNA damage and copy number aberrations (CNAs), which could eventually lead to their resistance to chemotherapy treatment. Tissue sections from chemotherapy-treated DA WTs (n = 12) were compared with chemotherapy-treated nonanaplastic WTs (n = 15) in a tissue microarray system, enabling analysis of 769 tumor regions. All regions were scored for anaplastic features and immunohistochemistry was used to quantify p53 expression, proliferation index (Ki67), and DNA double-strand breaks (γH2AX). CNAs were assessed by array-based genotyping and TP53 mutations using targeted sequencing. Proliferation index and the frequency of DNA double-strand breaks (γH2AX dot expression) increased with higher anaplasia scores. Almost all (95.6%) areas with full-scale anaplasia had TP53 mutations or loss of heterozygosity, along with an increased amount of CNAs. Interestingly, areas with wild-type TP53 with loss of heterozygosity and only one feature of anaplasia (anaplasia score 1) also had significantly higher proliferation indices, more DNA double-strand breaks, and more CNAs than regions without any anaplastic features (score 0); such areas may be preanaplastic cell populations under selective pressure for TP53 mutations. In conclusion, we suggest that chemoresistance of DA WTs may be partly explained by a high proliferative capability of anaplastic cells, which also have a high burden of double-stranded DNA breaks and CNAs, and that there is a gradual emergence of anaplasia in WT.

Resolving the Pathogenesis of Anaplastic Wilms Tumors through Spatial Mapping of Cancer Cell Evolution

PURPOSE

While patients with intermediate-risk (IR) Wilms tumors now have an overall survival (OS) rate of almost 90%, those affected by high-stage tumors with diffuse anaplasia have an OS of only around 50%. We here identify key events in the pathogenesis of diffuse anaplasia by mapping cancer cell evolution over anatomic space in Wilms tumors.

EXPERIMENTAL DESIGN

We spatially mapped subclonal landscapes in a retrospective cohort of 20 Wilms tumors using high-resolution copy-number profiling and TP53 mutation analysis followed by clonal deconvolution and phylogenetic reconstruction. Tumor whole-mount sections (WMS) were utilized to characterize the distribution of subclones across anatomically distinct tumor compartments.

RESULTS

Compared with non-diffuse anaplasia Wilms tumors, tumors with diffuse anaplasia showed a significantly higher number of genetically distinct tumor cell subpopulations and more complex phylogenetic trees, including high levels of phylogenetic species richness, divergence, and irregularity. All regions with classical anaplasia showed TP53 alterations. TP53 mutations were frequently followed by saltatory evolution and parallel loss of the remaining wild-type (WT) allele in different regions. Morphologic features of anaplasia increased with copy-number aberration (CNA) burden and regressive features. Compartments demarcated by fibrous septae or necrosis/regression were frequently (73%) associated with the emergence of new clonal CNAs, although clonal sweeps were rare within these compartments.

CONCLUSIONS

Wilms tumors with diffuse anaplasia display significantly more complex phylogenies compared with non-diffuse anaplasia Wilms tumors, including features of saltatory and parallel evolution. The subclonal landscape of individual tumors was constrained by anatomic compartments, which should be considered when sampling tissue for precision diagnostics.

Retinoic acid promotes differentiation of WiT49- but not of CCG99-11 Wilms tumour cells

BACKGROUND

Most children with Wilms tumour are successfully treated with multidrug chemotherapy and surgery. These treatments cause severe side effects for the patients, an issue that needs to be addressed by exploring other treatment options with less or no side effects. One option is to complement current therapies with agents that could potentially induce tumour cell differentiation, for example retinoic acid (RA).

AIMS

To facilitate quick assessment of an agent's effect on Wilms tumour differentiation by a rapid in vitro model system.

METHODS AND RESULTS

Here WiT49 and CCG99-11 Wilms tumour cells were treated with 10 μM RA for 72 h or 9 days. Cultured cells were scraped off from Petri dishes, pelleted and embedded in paraffin in the same way as clinical tumour specimens are preserved. Cell morphology and differentiation were evaluated by analyses of haematoxylin eosin (H&E) and immunohistochemical stainings. Based on H&E, WT1 and CKAE1/3 stainings, RA treatment induced further epithelial differentiation of WiT49 cells, whereas there was no sign of induced maturation in CCG99-11 cells. Ki67 staining showed that RA inhibited cell proliferation in both cell lines.

CONCLUSIONS

Our study shows that in vitro culturing of WiT49 and CCG99-11 cells, followed by pelleting and paraffin embedding of cell pellets, could aid in a quick evaluation of potential differentiating agents against Wilms tumour. In addition, our results strengthen previous results that retinoic acid could be a potential complement to regular Wilms tumour treatment.

Macrophage infiltration promotes regrowth in MYCN-amplified neuroblastoma after chemotherapy

Despite aggressive treatment, the 5-year event-free survival rate for children with high-risk neuroblastoma is <50%. While most high-risk neuroblastoma patients initially respond to treatment, often with complete clinical remission, many eventually relapse with therapy-resistant tumors. Novel therapeutic alternatives that prevent the recurrence of therapy-resistant tumors are urgently needed. To understand the adaptation of neuroblastoma under therapy, we analyzed the transcriptomic landscape in 46 clinical tumor samples collected before (PRE) or after (POST) treatment from 22 neuroblastoma patients. RNA sequencing revealed that many of the top-upregulated biological processes in POST MYCN amplified (MNA⁺) tumors compared to PRE MNA⁺ tumors were immune-related, and there was a significant increase in numerous genes associated with macrophages. The infiltration of macrophages was corroborated by immunohistochemistry and spatial digital protein profiling. Moreover, POST MNA⁺ tumor cells were more immunogenic compared to PRE MNA⁺ tumor cells. To find support for the macrophage-induced outgrowth of certain subpopulations of immunogenic tumor cells following treatment, we examined the genetic landscape in multiple clinical PRE and POST tumor samples from nine neuroblastoma patients revealing a significant correlation between an increased amount of copy number aberrations (CNA) and macrophage infiltration in POST MNA⁺ tumor samples. Using an in vivo neuroblastoma patient-derived xenograft (PDX) chemotherapy model, we further show that inhibition of macrophage recruitment with anti-CSF1R treatment prevents the regrowth of MNA⁺ tumors following chemotherapy. Taken together, our work supports a therapeutic strategy for fighting the relapse of MNA⁺ neuroblastoma by targeting the immune microenvironment.

IL4 promotes phagocytosis of murine leukemia cells counteracted by CD47 upregulation

Cytokines are key regulators of tumor immune surveillance by controlling immune cell activity. Here, we investigated whether interleukin 4 (IL4) has antileukemic activity via immune-mediated mechanisms in an in vivo murine model of acute myeloid leukemia driven by the MLL-AF9 fusion gene. Although IL4 strongly inhibited leukemia development in immunocompetent mice, the effect was diminished in immune-deficient recipient mice, demonstrating that the antileukemic effect of IL4 in vivo is dependent on the host immune system. Using flow cytometric analysis and immunohistochemistry, we revealed that the antileukemic effect of IL4 coincided with an expansion of F4/80+ macrophages in the bone marrow and spleen. To elucidate whether this macrophage expansion was responsible of the antileukemic effect, we depleted macrophages in vivo with clodronate liposomes. Macrophage depletion eliminated the antileukemic effect of IL4, showing that macrophages mediated the IL4-induced killing of leukemia cells. In addition, IL4 enhanced murine macrophage-mediated phagocytosis of leukemia cells in vitro. Global transcriptomic analysis of macrophages revealed an enrichment of signatures associated with alternatively activated macrophages and increased phagocytosis upon IL4 stimulation. Notably, IL4 concurrently induced Stat6-dependent upregulation of CD47 on leukemia cells, which suppressed macrophage activity. Consistent with this finding, combining CD47 blockade with IL4 stimulation enhanced macrophage-mediated phagocytosis of leukemia cells. Thus, IL4 has two counteracting roles in regulating phagocytosis in mice; enhancing macrophage-mediated killing of leukemia cells, but also inducing CD47 expression that protects target cells from excessive phagocytosis. Taken together, our data suggests that combined strategies that activate macrophages and block CD47 have therapeutic potential in AML.

A dynamic mutational landscape associated with an inter-regionally diverse immune response in malignant rhabdoid tumour

Malignant rhabdoid tumour (MRT) is a childhood neoplasm of high malignancy characterised by biallelic mutation and/or loss of the epigenetic master regulator SMARCB1, accompanied by no or few other oncogenic drivers. In spite of their generally low mutational burden, an intratumoural T-cell response has been reported in a subset of MRTs, indicating that immune checkpoint inhibition may be considered a viable therapy option for some patients. We assess here the evolution over time and space of predicted neoantigens and indicators of immune checkpoint status in two MRT patients who progressed under treatment. Both patients showed an accumulation of novel clonal and subclonal mutations, including predicted neoantigens, in metastases compared to their inferred ancestral clones in the primary tumours. The first patient had peritoneal metastases from an MRT of the liver. Clonal deconvolution revealed polyclonal seeding from the primary tumour to a single metastatic site, followed by a local subclonal burst of mutations. The second patient had a renal MRT with multiple pulmonary metastases, each of which could be traced back to a single genetically unique founder cell, with formation of novel subclones in two metastases. Both patients showed a regionally heterogeneous landscape of predicted neoantigens and of tumour-infiltrating lymphocytes expressing CD8 and PD1. In both patients, some tumour regions fulfilled established criteria for PD-L1 positivity (> 1% of tumour cells), while others did not. This suggests that even in a tumour type like MRT, with a single driver mutation, there can be heterogeneity in neoantigen repertoire, immune response, and biomarkers for checkpoint blockade among sampled locations. This must be taken into account when assessing progressed MRT patients for checkpoint inhibition therapy. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

The Iroquois homeobox proteins IRX3 and IRX5 have distinct roles in Wilms tumour development and human nephrogenesis

Wilms tumour is a paediatric malignancy with features of halted kidney development. Here, we demonstrate that the Iroquois homeobox genes IRX3 and IRX5 are essential for mammalian nephrogenesis and govern the differentiation of Wilms tumour. Knock‐out Irx3⁻/Irx5⁻ mice showed a strongly reduced embryonic nephron formation. In human foetal kidney and Wilms tumour, IRX5 expression was already activated in early proliferative blastema, whereas IRX3 protein levels peaked at tubular differentiation. Accordingly, an orthotopic xenograft mouse model of Wilms tumour showed that IRX3^−/− cells formed bulky renal tumours dominated by immature mesenchyme and active canonical WNT/β‐catenin‐signalling. In contrast, IRX5^−/− cells displayed activation of Hippo and non‐canonical WNT‐signalling and generated small tumours with abundant tubulogenesis. Our findings suggest that promotion of IRX3 signalling or inhibition of IRX5 signalling could be a route towards differentiation therapy for Wilms tumour, in which WNT5A is a candidate molecule for enforced tubular maturation. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Women's experiences of miscarriage related to diagnosis, duration, and type of treatment

INTRODUCTION

Women with miscarriage experience several negative emotional feelings such as grief, isolation, coping, and despair. However, less is known about how the type of treatment and diagnosis of miscarriage influence the emotional experience.

MATERIAL AND METHODS

The present study was a randomized prospective longitudinal cohort study, in which women with spontaneous miscarriage (n = 35), and women with missed miscarriage (n = 67), were included to answer three validated questionnaires: Revised Impact of Miscarriage Scale, Perinatal Grief Scale, and Montgomery and Åsberg Depression Rating Scale, concerning experience of miscarriage, psychological well-being, and mental health 1 week and 4 months after finalized treatment.

RESULTS

There was no difference between the 2 diagnosis groups in feelings as measured by Revised Impact of Miscarriage Scale, Montgomery and Åsberg Depression Rating Scale, and Perinatal Grief Scale 1 week after the miscarriage. However, the psychological well-being improved significantly 4 months after the miscarriage. Separated by treatment, women treated with misoprostol alone had more depressive symptoms than women treated with misoprostol and subsequent vacuum aspiration.

CONCLUSIONS

It can be concluded that diagnosis of miscarriage had limited influence on the experiences of miscarriage, but shorter duration of treatment with misoprostol and subsequent vacuum aspiration resulted in fewer depressive symptoms.

Longitudinal study of emotional experiences, grief and depressive symptoms in women and men after miscarriage

OBJECTIVE

Although miscarriage is common and affects up to 20% of pregnant women, little is known about these couples' short term and long term experiences after miscarriage. The aim of the present study was to study emotional experience, grief and depressive symptoms in women and men, one week and four months after miscarriage.

RESEARCH DESIGN /SETTING

Women, (n = 103), and their male partner (n = 78), were recruited at the gynecological clinic after miscarriage. Control women were recruited from the general population. Three validated questionnaires concerning psychological wellbeing and mental health, RIMS, PGS and MADRS-S were answered by the participants one week and four months after the miscarriage.

FINDINGS

It was shown that for women, the emotional experiences of miscarriage, grief and depressive symptoms were more pronounced than for their male partners. Grief and depressive symptoms were reduced with time, which was not the case for the emotional experiences of miscarriage. Previous children was favorable for emotional experience while previous miscarriage or infertility treatment made the emotional experience worse.

CONCLUSION

Grief and depressive symptoms is reduced over time while emotional experiences such as isolation, loss of baby and a devastating event persist for longer time than four months. Lack of previous children, previous miscarriage and infertility diagnosis could increase negative emotional experiences after miscarriage, this was especially pronounced for grief reaction. The questionnaires could be used both clinically and in research to understand the emotional experiences after miscarriage.

Aberrant epigenetic regulation in clear cell sarcoma of the kidney featuring distinct DNA hypermethylation and EZH2 overexpression

The global methylation profile and the mutational status of 633 specific epigenetic regulators were analyzed in the pediatric tumor clear cell sarcoma of the kidney (CCSK). Methylation array analyses of 30 CCSKs revealed CCSK tumor DNA to be globally hypermethylated compared to Wilms tumor, normal fetal kidney, and adult kidney. The aberrant methylation pattern of CCSKs was associated with activation of genes involved in embryonic processes and with silencing of genes linked to normal kidney function. No epigenetic regulator was recurrently mutated in our cohort, but a mutation in the key epigenetic regulator EZH2 was discovered in one case. EZH2 mRNA was significantly higher in CCSK compared to Wilms tumor and normal kidney, and the EZH2 protein was strongly expressed in more than 90 % of CCSK tumor cells in 9/9 tumors analyzed. This was in striking contrast to the lack of EZH2 protein expression in Wilms tumor stromal elements, indicating that EZH2 could be explored further as a diagnostic marker and a potential drug target for CCSK.

Expression of barley SUSIBA2 transcription factor yields high-starch low-methane rice

Atmospheric methane is the second most important greenhouse gas after carbon dioxide, and is responsible for about 20% of the global warming effect since pre-industrial times. Rice paddies are the largest anthropogenic methane source and produce 7-17% of atmospheric methane. Warm waterlogged soil and exuded nutrients from rice roots provide ideal conditions for methanogenesis in paddies with annual methane emissions of 25-100-million tonnes. This scenario will be exacerbated by an expansion in rice cultivation needed to meet the escalating demand for food in the coming decades. There is an urgent need to establish sustainable technologies for increasing rice production while reducing methane fluxes from rice paddies. However, ongoing efforts for methane mitigation in rice paddies are mainly based on farming practices and measures that are difficult to implement. Despite proposed strategies to increase rice productivity and reduce methane emissions, no high-starch low-methane-emission rice has been developed. Here we show that the addition of a single transcription factor gene, barley SUSIBA2 (refs 7, 8), conferred a shift of carbon flux to SUSIBA2 rice, favouring the allocation of photosynthates to aboveground biomass over allocation to roots. The altered allocation resulted in an increased biomass and starch content in the seeds and stems, and suppressed methanogenesis, possibly through a reduction in root exudates. Three-year field trials in China demonstrated that the cultivation of SUSIBA2 rice was associated with a significant reduction in methane emissions and a decrease in rhizospheric methanogen levels. SUSIBA2 rice offers a sustainable means of providing increased starch content for food production while reducing greenhouse gas emissions from rice cultivation. Approaches to increase rice productivity and reduce methane emissions as seen in SUSIBA2 rice may be particularly beneficial in a future climate with rising temperatures resulting in increased methane emissions from paddies.

Severe symptoms of gastro-oesophageal reflux disease are associated with cardiovascular disease and other gastrointestinal symptoms, but not diabetes: a population-based study

BACKGROUND

Few population-based studies have examined comorbidity in relation to gastro-oesophageal reflux disease (GERD).

AIM

To study the association between cardiovascular disease, diabetes, gastrointestinal symptoms and GERD.

METHODS

Population-based, cross-sectional, case-control study based on a large Norwegian health survey conducted in 1995-97. Among 65,333 participants, 3153 persons reporting severe reflux symptoms were defined as cases, and 40,210 persons without such symptoms were defined as controls. Data on cardiovascular disease, diabetes, gastrointestinal symptoms and potential confounders were collected through questionnaires. Odds ratios (OR) with 95% confidence intervals (CI) were estimated using unconditional logistic regression, in crude and adjusted models.

RESULTS

In the crude models, positive associations were observed between myocardial infarction (OR 1.7, 95% CI 1.4-2.1), angina pectoris (OR 2.5, 95% CI 2.1-2.9) and stroke (OR 1.6, 95% CI 1.2-2.1) and risk of GERD. The associations were attenuated in the adjusted models, but remained significant for angina pectoris (OR 1.9, 95% CI 1.6-2.2). No association was observed between diabetes and GERD. Strong positive associations were seen between all studied gastrointestinal symptoms, i.e. nausea, diarrhoea and constipation, and risk of GERD.

CONCLUSIONS

This population-based study indicates that myocardial infarction, angina pectoris, stroke and symptoms of nausea, diarrhoea and constipation are associated with GERD.

Severe gastro-oesophageal reflux symptoms in relation to anxiety, depression and coping in a population-based study

BACKGROUND

The association between psychiatric disorders and gastro-oesophageal reflux symptoms is uncertain, and few population-based studies are available.

AIM

To examine the association between psychiatric and psychological factors and reflux symptoms.

METHODS

Population-based, cross-sectional, case-control study based on two health surveys conducted in the Norwegian county Nord-Trondelag in 1984-1986 and 1995-1997. Reflux symptoms were assessed in the second survey, including 65,333 participants (70% of the county's adult population). 3153 subjects reporting severe reflux symptoms were defined as cases and 40,210 subjects without symptoms were defined as controls. Data were collected in questionnaires. Odds ratio with 95% confidence intervals were estimated using unconditional logistic regression, in adjusted models.

RESULTS

Subjects reporting anxiety without depression had a 3.2-fold (95% CI: 2.7-3.8) increased risk of reflux, subjects with depression without anxiety had a 1.7-fold (95% CI: 1.4-2.1) increased risk and subjects with both anxiety and depression had a 2.8-fold (95% CI: 2.4-3.2) increased risk, compared to subjects without anxiety/depression. We observed a weak inverse association between one measure of covert coping and risk of reflux and a weak positive association between another coping measure and risk of reflux.

CONCLUSIONS

This population-based study indicates that anxiety and depression are strongly associated with reflux symptoms, while no consistent association regarding coping and reflux was found.

Airborne occupational exposures and risk of oesophageal and cardia adenocarcinoma

BACKGROUND

The reasons for the increasing incidence of and strong male predominance in patients with oesophageal and cardia adenocarcinoma remain unclear. The authors hypothesised that airborne occupational exposures in male dominated industries might contribute.

METHODS

In a nationwide Swedish population based case control study, 189 and 262 cases of oesophageal and cardia adenocarcinoma respectively, 167 cases of oesophageal squamous cell carcinoma, and 820 frequency matched controls underwent personal interviews. Based on each study participant's lifetime occupational history the authors assessed cumulative airborne occupational exposure for 10 agents, analysed individually and combined, by a deterministic additive model including probability, frequency, and intensity. Furthermore, occupations and industries of longest duration were analysed. Relative risks were estimated by odds ratios (OR), with 95% confidence intervals (CI), using conditional logistic regression, adjusted for potential confounders.

RESULTS

Tendencies of positive associations were found between high exposure to pesticides and risk of oesophageal (OR 2.3 (95% CI 0.9 to 5.7)) and cardia adenocarcinoma (OR 2.1 (95% CI 1.0 to 4.6)). Among workers highly exposed to particular agents, a tendency of an increased risk of oesophageal squamous cell carcinoma was found. There was a twofold increased risk of oesophageal squamous cell carcinoma among concrete and construction workers (OR 2.2 (95% CI 1.1 to 4.2)) and a nearly fourfold increased risk of cardia adenocarcinoma among workers within the motor vehicle industry (OR 3.9 (95% CI 1.5 to 10.4)). An increased risk of oesophageal squamous cell carcinoma (OR 3.9 (95% CI 1.2 to 12.5)), and a tendency of an increased risk of cardia adenocarcinoma (OR 2.8 (95% CI 0.9 to 8.5)), were identified among hotel and restaurant workers.

CONCLUSIONS

Specific airborne occupational exposures do not seem to be of major importance in the aetiology of oesophageal or cardia adenocarcinoma and are unlikely to contribute to the increasing incidence or the male predominance.

Sex hormones and oesophageal adenocarcinoma: influence of childbearing?

The male predominance of oesophageal adenocarcinoma might be explained by oestrogen protection in women. If true, female patients might have sex hormonal disturbances rendering impaired fertility. The influence of childbearing on the risk of oesophageal adenocarcinoma was investigated in a Swedish population-based case (n=63) -control (n=141) study. Childless women were not at increased risk compared to childbearing (OR=0.82; 95% CI=0.25-2.72), as neither were women with 0-1 children compared to women with at least three children (OR=0.93; 95% CI=0.35-2.49). In conclusion, we found no inverse association between childbearing and oesophageal adenocarcinoma.

Association of asthma and hay fever with irregular menstruation

BACKGROUND

There is some evidence that asthmatic women are more likely to have abnormal sex hormone levels. A study was undertaken to determine whether asthma and allergy were associated with irregular menstruation in a general population, and the potential role of asthma medication for this association.

METHODS

A total of 8588 women (response rate 77%) participated in an 8 year follow up postal questionnaire study of participants of the ECRHS stage I in Denmark, Estonia, Iceland, Norway, and Sweden. Only non-pregnant women not taking exogenous sex hormones were included in the analyses (n = 6137).

RESULTS

Irregular menstruation was associated with asthma (OR 1.54 (95% CI 1.11 to 2.13)), asthma symptoms (OR 1.47 (95% CI 1.16 to 1.86)), hay fever (OR 1.29 (95% CI 1.05 to 1.57)), and asthma preceded by hay fever (OR 1.95 (95% CI 1.30 to 2.96)) among women aged 26-42 years. This was also observed in women not taking asthma medication (asthma symptoms: OR 1.44 (95% CI 1.09 to 1.91); hay fever: OR 1.27 (95% CI 1.03 to 1.58); wheeze preceded by hay fever: OR 1.76 (95% CI 1.18 to 2.64)). Irregular menstruation was associated with new onset asthma in younger women (OR 1.58 (95% CI 1.03 to 2.42)) but not in women aged 42-54 years (OR 0.62 (95% CI 0.32 to 1.18)). The results were consistent across centres.

CONCLUSIONS

Younger women with asthma and allergy were more likely to have irregular menstruation. This could not be attributed to current use of asthma medication. The association could possibly be explained by common underlying metabolic or developmental factors. The authors hypothesise that insulin resistance may play a role in asthma and allergy.

Analysis of Borrelia burgdorferi IgG antibodies with a combination of IgG ELISA and VlsE C6 peptide ELISA

Enzyme-linked immunosorbent assays (ELISAs) were used to detect antibodies to the C6 peptide of the Borrelia burgdorferi VlsE protein and a selection of B. burgdorferi IgG antigens, separately and as a combination, in 355 serum specimens from blood donors and patients. Western immunoblotting was used as the reference method. The sensitivity of the combined analysis of IgG antigen and C6 peptide analysis was markedly superior to those of the separate analyses. When the C6 peptide and IgG results were concordant, the customary confirmatory Western immunoblotting assay could be omitted, thus reducing the time and cost of analysis.

Transformation and regeneration capacities for five Nordic barley elite cultivars--evaluation of tissue culture response and transient expression

Using both biolistic and Agrobacterium-mediated DNA delivery, we have investigated the transformation and regeneration capacity for five Nordic elite cultivars of barley. Transformation was followed as transient expression of the uidA or gfp gene in barley callus. Callus formation and regeneration of transformed callus were evaluated based on callus induction frequency, growth rate, callus appearance, and shoot formation frequency. From the accumulated results, one of the elite cultivars has been selected for our ongoing work in molecular breeding of barley.

Randomized trial of Lichtenstein versus Shouldice hernia repair in general surgical practice

BACKGROUND

The aim of the present randomized trial was to compare the Shouldice procedure and the Lichtenstein hernia repair with respect to recurrence rate, technical difficulty, convalescence and chronic pain. A further aim was to determine to what extent general surgeons in routine surgical practice were able to reproduce the excellent results reported from specialist hernia centres.

METHODS

Three hundred patients with primary inguinal hernia were randomized to either a Shouldice repair or to a tension-free Lichtenstein repair. In a pretrial training programme the five participating general surgeons were taught to perform the two techniques in a standard manner. Follow-up was performed after 8 weeks, 1 year and 3 years. The last examination was performed by an independent blinded assessor.

RESULTS

There was a significant difference in operating time in favour of the Lichtenstein technique. After a follow-up of 36-77 months seven recurrences were found in the Shouldice group (95 per cent confidence interval (c.i.) 1.3 to 8.1) and one in the mesh group (95 per cent c.i. 0.0 to 2.0). Chronic groin pain was reported by 4.2 and 5.6 per cent in the Shouldice and Lichtenstein groups respectively. It was characterized as mild or moderate in all except two patients who had the Shouldice operation.

CONCLUSION

Lichtenstein hernia repair was easier to learn, took less time and resulted in fewer recurrences. It was possible to achieve excellent results with this technique in a general surgical unit.

Engineering of the protein environment around the redox-active TyrZ in photosystem II. The role of F186 and P162 in the D1 protein of Synechocystis 6803

The photosystem II reaction centre protein D1 is encoded by the psbA gene. By activation of the silent and divergent psbA1 gene in the cyanobacterium Synechocystis 6803, a novel D1 protein, D1', was produced [Salih, G. & Jansson, C. (1997) Plant Cell 9, 869-878]. The D1' protein was found to be fully operational although it deviates from the normal D1 protein in 54 out of 360 amino acids. Two notable amino-acid substitutions in D1' are the replacements of F186 by a leucine and P162 by a serine. The F186 and P162 positions are located in the vicinity of the reaction centre chlorophyll dimer P680 and the redox-active Y161 (TyrZ), and F186 has been implicated in the electron transfer between Y161 and P680. The importance of F186 was addressed by construction of engineered D1 proteins in Synechocystis 6803. F186 was replaced by leucine, serine, alanine, tyrosine or tryptophan. Only the leucine replacement yielded a functional D1 protein. Other substitutions did not support photoautotrophic growth and the corresponding mutants showed no or very poor oxygen evolving activity. In the F186Y and F186W mutants, the D1 protein failed to accumulate to appreciable levels in the thylakoid membrane. The F186S mutation severely increased the light sensitivity of the D1 protein, as indicated by the presence of a 16-kDa proteolytic degradation product. We conclude that the hydrophobicity and van der Waals volume are the most important features of the residue at position 186. Exchanging P162 for a serine yielded no observable phenotype.

D1' centers are less efficient than normal photosystem II centers

One prominent difference between the photosystem II (PSII) reaction center protein D1' in Synechocystis 6803 and normal D1 is the replacement of Phe-186 in D1 with leucine in D1'. Mutants of Synechocystis 6803 producing only D1', or containing engineered D1 proteins with Phe-186 substitutions, were analyzed by 77 K fluorescence emission spectra, chlorophyll a fluorescence induction yield and decay kinetics, and flash-induced oxygen evolution. Compared to D1-containing PSII centers, D1' centers exhibited a 50% reduction in variable chlorophyll a fluorescence yield, while the flash-induced O(2) evolution pattern was unaffected. In the F186 mutants, both the P680(+)/Q(A)(-) recombination and O(2) oscillation pattern were noticeably perturbed.

Deletion mutagenesis of the 5' psbA2 region in Synechocystis 6803: identification of a putative cis element involved in photoregulation

Three Synechocystis 6803 mutants, with deletions in the upstream region of the light-regulated psbA2 gene, were constructed. All three mutants grew photoautotrophically but they were affected in psbA2 expression. In one of the mutants, DeltaU80, psbA2 transcription levels were not suppressed under low light conditions and production of psbA2 transcripts occurred also in darkness, in contrast to the situation in the control strain. Comparative sequence analyses of the mutants identified a hexanucleotide repeat as possible cis element in psbA2 light regulation. Electrophoresis mobility shift assays showed that protein binding to the hexanucleotide repeat decreased with light intensity, consistent with a hypothesis that the repeat harbors a binding site for a repressor protein. Repeats similar to that in psbA2 were found also in the upstream region of other light-regulated genes in Synechocystsis 6803. We refer to these hexanucleotide repeats as High Light Regulatory 1 (HLR1) sequences.

Multiresidue method for the gas chromatographic determination of pesticides in honey after solid-phase extraction cleanup

A new multiresidue method is described for the determination of pesticides in honey. The method involves dissolution of the honey in a methanol-water mixture, followed by solid-phase extraction cleanup and gas chromatographic determination. Twenty-six pesticides used on flowering field crops, on flowering fruit and vegetables, or as acaricides to control Varroa jacobsoni in beehives are determined by the method. Recoveries from honey, spiked at 0.02-1.6 mg/kg, ranged from 85 to 127% with a relative standard deviation (RSD) of 2-16%, except for the RSD of 27% for captan at 0.05 mg/kg.

Transformation of nuclear and plastomic plant genomes by biolistic particle bombardment

Microprojectile bombardment is a powerful method for the transformation of various organisms and tissues. For plants, the biolistic approach is primarily used for transformation of cereals and other monocotyledons, as well as for dicotyledonous plants shown to be recalcitrant to Agrobacterium-based transformation of organellar genomes, and transformation of plant and algal chloroplasts has recently been reported. In this protocol paper we provide methods for nuclear and plastomic transformation of plants using the biolistic technique.

Analyses of isoamylase gene activity in wild-type barley indicate its involvement in starch synthesis

The notion of debranching enzyme activity as a participant in starch synthesis is gaining acceptance. Inconsistent reports from mutant analyses implicate either isoamylase or pullulanase as a determinant in amylopectin formation and whether wild-type plants utilize one or the other, or both, of these debranching enzymes in starch synthesis is unclear. Recent results on the sul mutant in maize suggest that both forms of debranching enzymes might be involved in amylopectin formation. We wished to find out if isoamylase takes part in starch synthesis by comparing isoamylase gene activity under three conditions: (1) during starch accumulation in developing sink tissues; (2) during starch degradation in germinating seeds; (3) in ectopic expression after applying sucrose, a starch precursor. We isolated the gene for barley isoamylase, isol, and analysed its expression and regulation in germinating seeds, developing endosperm and vegetative tissues, and compared the isoamylase gene expression in sink tissues from three different species. Our results indicate that isoamylase gene activity is involved in starch synthesis in wild-type plants and is modulated by sucrose.

Engineering of N-terminal threonines in the D1 protein impairs photosystem II energy transfer in Synechocystis 6803

Mutants of the cyanobacterium Synechocystis sp. PCC 6803 with N-terminal changes in the photosystem (PSII) II D1 protein were analysed by flash-induced oxygen evolution, chlorophyll a fluorescence decay kinetics and 77 K fluorescence emission spectra. The data presented here show that mutations of the Thr-2, Thr-3 and Thr-4 in D1 do not influence the oxygen evolution. A perturbation on the acceptor side was observed and the importance of the N-terminal threonines for an efficient energy transfer between the phycobilisome and PSII and for stability of the PSII complex was demonstrated.

The two genes encoding starch-branching enzymes IIa and IIb are differentially expressed in barley

The sbeIIa and sbeIIb genes, encoding starch-branching enzyme (SBE) IIa and SBEIIb in barley (Hordeum vulgare L.), have been isolated. The 5' portions of the two genes are strongly divergent, primarily due to the 2064-nucleotide-long intron 2 in sbeIIb. The sequence of this intron shows that it contains a retro-transposon-like element. Expression of sbeIIb but not sbeIIa was found to be endosperm specific. The temporal expression patterns for sbeIIa and sbeIIb were similar and peaked around 12 d after pollination. DNA gel-blot analysis demonstrated that sbeIIa and sbeIIb are both single-copy genes in the barley genome. By fluorescence in situ hybridization, the sbeIIa and sbeIIb genes were mapped to chromosomes 2 and 5, respectively. The cDNA clones for SBEIIa and SBEIIb were isolated and sequenced. The amino acid sequences of SBEIIa and SBEIIb were almost 80% identical. The major structural difference between the two enzymes was the presence of a 94-amino acid N-terminal extension in the SBEIIb precursor. The (beta/alpha)8-barrel topology of the alpha-amylase superfamily and the catalytic residues implicated in branching enzymes are conserved in both barley enzymes.

Site-specific mutations of the N-terminal threonines in the D1 protein affects photoautotrophic growth but not D1 protein stability in Synechocystis 6803

The cyanobacterium Synechocystis 6803 was engineered to produce a D1 protein where one or more of the N-terminal threonines at positions 2, 3 and 4 were replaced by other amino acid residues. No phenotypic effects were found for the T2S or T2L mutations, whereas the T2V, T2L;T4V and T2V;T3V;T4V mutations resulted in reduced photoautotrophic growth rate and oxygen evolving activity. The mutant strain T2V;T3V;T4V exhibited an oxygen evolution activity that was only half of that for the wild-type strain. Despite of that, both accumulation and stability of the D1 protein in the thylakoid membrane appeared unaffected in the mutant.

Prevalence of bronchial hyper-responsiveness in the southern, central and northern parts of Sweden

Studies have suggested that there is a higher prevalence of asthma in northern Sweden than in southern Sweden. Bronchial hyper-responsiveness (BHR) has been shown to be associated with asthma. The aim of this study was to explore the prevalence of bronchical hyper-responsiveness in different parts of Sweden. As part of the European Community Respiratory Health Survey (ECRHS), interviews, skin prick tests, lung function tests and methacholine provocation tests of the airways were performed in 1448 randomly selected subjects in southern, central and northern Sweden. The Mefar dosimeter was used according to the ECRHS protocol. The responsiveness was calculated both as the PD20 and as the dose response slope (DRS). BHR was defined as a PD20 of < or = 1.6 mg. Atopy was defined as at least one skin prick test of > or = 3 mm. The prevalence of BHR was 12.7%, 10.6% in men and 15.0% in women. No difference in prevalence was found between the three different regions of Sweden. The prevalence of BHR was higher in women than in men and higher in smokers than in non-smokers. Using multiple logistic regression, with BHR as the dependent variable, atopy, being female, having a low FEV1 (% predicted) and smoking (both own and passive) increased the odds of having BHR, while age and the region of Sweden did not influence BHR. Defining BHR as a PD20 of < or = 1.0 mg or a PD20 of < or = 2.0 mg did not change this. Multiple regression using log DRS as the dependent variable produced the same result. Both BHR and increasing DRS were associated with self-reported wheezing, attacks of shortness of breath during the daytime at rest or after strenuous activity, being awakened by a feeling of tightness in the chest or an attack of shortness of breath. In subjects without self-reported asthma, BHR was associated with self-reported wheezing and attacks of shortness of breath after strenuous activity. In conclusion, we found that the prevalence of BHR in the three investigated areas was 12.7%. We found a trend towards a higher prevalence of BHR in the most northerly of the study areas, but the difference between the areas was not statistically significant. BHR and DRS were associated with atopy, smoking, female sex and FEV1 (% predicted). The reporting of symptoms from the airways was associated with the degree of bronchical responsiveness.

Hormonal status of short children born small for gestational age

The present study was undertaken to evaluate the hormonal status in a subgroup of prepubertal children born small for gestational age (SGA) who lacked postnatal catch-up growth. In this subgroup, a reduced rate of growth hormone (GH) secretion was found, compared with reference groups of healthy children born appropriate for gestational age, of either normal or short stature at the time of investigation. In addition, an abnormal pattern of GH secretion was observed in short children born SGA, which was most pronounced in the younger children, and involved an increased frequency of GH peaks of low amplitude, combined with increased baseline secretion. Levels of insulin-like growth factor I (IGF-I) and IGF-binding protein-3 were also reduced in short children born SGA, compared with the reference groups. These findings may explain, in part, the lack of postnatal catch-up growth in short children born SGA.

Increased LH and FSH secretion after cranial irradiation in boys

The effect of high-dose cranial- and craniospinal irradiation and chemotherapy on the gonadotropin-sex steroid axis was studied during different stages of puberty by measuring pulsatile secretion of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone. The patients were thirteen boys who had been treated for malignant brain tumor residing well away from the hypothalamo-pituitary region. The median time to follow-up was 9 (1-16) years. The onset of puberty was early in the patients, median 10.5 years, compared to the average age for Swedish boys, which is at median 12.4 years. There was, before puberty, no significant difference in LH and FSH secretion between patients and a control group of normal boys. In early, mid- and late stages of puberty, however, LH and FSH secretion was increased in the patients overall, whereas testosterone secretion was maintained within the normal range in spite of signs of gonadotoxocity with small testicular volumes. These results indicate that the vulnerable parts of the gonadotropin releasing hormone (GnRH)-gonadotropin (LH, FSH)-gonadal axis are the regulatory system that determines the timing of pubertal induction and the gonads. The GnRH-LH, FSH-releasing neurons appear relatively resistant to cranial irradiation as they are able to respond with supranormal LH and FSH levels for long periods of time after treatment.

Growth response to growth hormone (GH) treatment relates to serum insulin-like growth factor I (IGF-I) and IGF-binding protein-3 in short children with various GH secretion capacities. Swedish Study Group for Growth Hormone Treatment

The purpose of the study was to evaluate the relationship between the 1-yr (n = 193) and 2-yr (n = 128) growth response and the individual serum concentrations of insulin-like growth factor I (IGF-I) and IGF-binding protein 3 (IGFBP-3) before and during GH treatment. Our study group of prepubertal short children had from very low to high GH secretory capacity, estimated during an arginine-insulin tolerance test, and the ages ranged from 3-15 yr at the start of treatment. Their serum levels of IGF-I and IGFBP-3 were low before treatment compared to those in an age-related reference group of prepubertal children and increased significantly from the start to 1 month of GH treatment. The mean increase in height SD score was 0.80 SD score after 1 yr of GH treatment and 1.26 SD score after 2 yr, with a wide range. In univariate analyses the highest correlation coefficients to the 2-yr growth response were found to be vs. the following variables from the start of treatment: IGF-I SD score (r = -0.49), log maximum GH concentration (log GHmax) during the arginine-insulin tolerance test (r = -0.47), difference between the height SD score of the individual child and the midparental height SD score (diffSD score; r = -0.45), IGFBP-3 SD score (r = -0.39), age (r = -0.30), short term change in IGFBP-3 SD score (r = 0.37), and IGF-I SD score (r = 0.34). In multivariate stepwise regression analysis, 41% of the variation in the 2-yr growth response could be explained by IGF-I SD score or log GHmax together with age at the start of treatment, weight SD score at 1 yr of age, and diffSD score. When both IGF-I SD score and GHmax were included and when the short term changes in IGF-I SD score were added, 46% and 58% of the variation, respectively, could be explained. The regression algorithms using different combinations of variables and their corresponding prediction intervals are also presented.

Increased proportion of circulating non-22-kilodalton growth hormone isoforms in short children: a possible mechanism for growth failure

Current knowledge about the interaction between GH and its receptor suggests that the molecular heterogeneity of circulating GH may have important implications for growth. The aim of this study was to investigate the proportion of circulating non-22-kDa GH isoforms in prepubertal children with short stature (height less than -2 SD score) of different etiologies. We have also evaluated the relationships among the ratio of non-22-kDa GH isoforms, auxology, and spontaneous GH secretion. The study groups consisted of 17 girls with Turner's syndrome (TS), aged 3-13 yr, 25 children born small for gestational age (SGA) without postnatal catch-up growth, aged 3-13 yr; and 24 children with idiopathic short stature (ISS), aged 4-15 yr. The results were compared with those from 23 prepubertal healthy children of normal stature (height +/- 2 SD score), aged 4-13 yr. Serum non-22-kDa GH levels, expressed as a percentage of the total GH concentration, were determined by the 22-kDa GH exclusion assay, which is based on immunomagnetic extraction of monomeric and dimeric 22-kDa GH from serum and quantitation of non-22-kDa GH using a polyclonal antibody-based GH assay. All samples were selected from spontaneous GH peaks in 24-h GH profiles. The median proportion of non-22-kDa GH isoforms was increased in children born SGA (9.8%; P = 0.05) and girls with TS (9.9%; P = 0.01), but not in the group of children with ISS (8.9%), compared with that in normal children (8.1%). Individually, increased proportions of non-22-kDa GH isoforms, with values more than 2 SD above the mean for the normal group, were observed in 5 girls with TS, 5 children born SGA, and 4 children with ISS. In children born SGA, the proportion of non-22-kDa GH isoforms was directly correlated with different estimates of spontaneous GH secretion [mean 24-h GH concentration (r = 0.41; P = 0.04), area under the curve over baseline (r = 0.41; P = 0.04), and GH peak area (r = 0.61; P = 0.003)], whereas it was inversely correlated with height SD score (r = -0.42; P = 0.04). In conclusion, an increased proportion of circulating non-22-kDa GH isoforms was observed at spontaneous GH peaks in some non-GH-deficient short children. Our results suggest that the ratio of non-22-kDa GH isoforms in the circulation may have important implications for normal and abnormal growth.

Circulating non-22 kDa growth hormone isoforms in healthy children of normal stature: relation to height, body mass and pubertal development

The proportion of non-22 kDa GH isoforms was evaluated in 93 healthy children (48 boys aged 6.8-18.4 years and 45 girls aged 3.9-18.4 years) of normal stature (height +/- 2 s.d. score) at different stages of puberty. In addition, correlations among the proportion of non-22 kDa GH isoforms, auxology, spontaneous GH secretion and biochemical measurements were investigated. Serum non-22 kDa GH levels, expressed as percentage of total GH concentration in the samples, were determined by the 22 kDa GH exclusion assay, in which monomeric and dimeric 22 kDa GH are removed from serum and the non-22 kDa GH isoforms are quantitated using a polyclonal antibody GH assay. Samples were selected from spontaneous GH peaks in 24-h GH profiles. For boys, the median proportion of non-22 kDa GH isoforms was 8.5% (range 3.2-26.6%) and for girls it was 9.6% (1.8-17.4%), with no influence of age and no sex-related difference in prepubertal (boys, 7.2%; girls, 8.8%) or pubertal children (boys, 9.1%; girls, 9.9%). However, the median proportion of non-22 kDa GH isoforms was significantly higher in pubertal boys (9.1%) than in prepubertal boys (7.2%; P = 0.03). In pubertal boys, height S.D. scores (SDS) were inversely correlated to the proportion of non-22 kDa GH isoforms (r = -0.38; P = 0.02), especially at mid-puberty (r = -0.7; P = 0.01), indicating that the presence of increased amounts of circulating non-22 kDa GH isoforms was associated with less growth. In prepubertal children, positive correlations between non-22 kDa GH and weight SDS (r = 0.46; P = 0.03), weight-for-height SDS (r = 0.51; P = 0.01) and body mass index (r = 0.42; P = 0.04) were observed. No significant correlations were seen with spontaneous GH secretion or measurements of IGF-1, IGF-binding protein-3, insulin and leptin. These findings in normal children indicate that the proportion of circulating non-22 kDa GH isoforms may have physiologic significance for growth and metabolism in different stages of development, and emphasize the importance of evaluating the circulating ratio of 22 kDa and non-22 kDa GH in children with growth disorders.

Activation of the silent psbA1 gene in the cyanobacterium Synechocystis sp strain 6803 produces a novel and functional D1 protein

The photosystem II reaction center protein D1 in Synechocystis sp strain 6803 is encoded by the psbA2 and psbA3 genes of the three-membered psbA gene family. The silent and divergent psbA1 copy of the psbA gene family was activated by exchanging part of its upstream region with a corresponding fragment of the psbA2 copy. The light-regulated expression of the activated psbA1 gene showed that the inserted psbA2 segment contains the information necessary for light-dependent as well as high-light-stimulated transcription. The activated psbA1 gene expressed a novel D1 protein, D1'. A mutant strain containing psbA1 as the only active psbA gene grew photoautotrophically at a rate comparable to that of the wild type. This finding demonstrates that despite its unusual amino acid sequence, D1 is exchangeable for D1 in the photosystem II complex, at least under normal laboratory conditions. The D1' protein was found to have a degradation rate similar to that of the D1 protein under low- or high-light conditions. Another mutant containing the activated psbA1 gene together with the psbA2 and psbA3 genes produced both the D1 and D1' proteins.

Growth hormone (GH) assays: influence of standard preparations, GH isoforms, assay characteristics, and GH-binding protein

The impact of the adoption of the new biosynthetic growth hormone (GH) WHO International Reference Preparation (IRP 88/624), and the recommendation to report results in microgram/L instead of mU/L, is described. Conversion factors were determined by comparing both the linear and nonlinear relations of the GH values. The Pharmacia polyclonal IRMA (p-IRMA) and the DELFIA monoclonal time-resolved immunofluorometric assay (trIFMA) with kit calibrators calibrated either against the pituitary-derived WHO IRP 80/505 or the new 88/624 were evaluated. Conversion factors of 4.17 mU/L = 1 microgram/L for the p-IRMA and 4.31 mU/L = 1 microgram/L for the trIFMA were necessary. Different cross-reactivity patterns for the deaminated and dimer 22-kDa, 20-kDa, and 17-kDa GH isoforms were found. Expected GH recovery was similar when the measured values were adjusted according to the results of the cross-reactivity study.

Influence of gender on the correlation between plasma growth hormone profiles and urinary growth hormone excretion

A lot of interest has been directed towards the measurement of urinary growth hormone (GH) excretion instead of plasma GH profiles or provocation tests. We investigated the factors influencing the relationship between 24- and 3-hour plasma GH profiles and urinary GH excretion in a cohort of 113 pediatric patients with growth disorders and healthy volunteers. Plasma and urinary GH were measured by polyclonal immunoassays differing in cross-reactivity with 20 kD GH (100 versus 46%), but not with 22-kD, dimer, deamidated and pituitary GH. In the 24-hour urine samples, only urinary GH excretion expressed as nanograms per 24 h correlated with plasma GH parameters, whereas the correlations for short-term samples were strongest if urinary GH excretion was expressed as nanograms per gram creatinine (r = 0.70-79, p < 0.00005-0.0001). In short-term samples urinary GH excretion depends on urinary volume and should thus be expressed in nanograms per gram creatinine, whereas 24-hour samples correlate best when urinary GH is expressed as nanograms per period. We found a significant sex difference (p < 0.02) in the correlation between 24-hour plasma GH profiles and urinary GH excretion with strong correlations in the female group (r = 0.63-0.78, p < 0.00005-0.0002) and a lack of correlation in the male group. The sex difference in the correlations between serum and urinary GH may reflect sex differences in GH profiles and metabolism, with urinary GH better reflecting the basal and slowly clearing portion of plasma GH than spontaneous GH peaks. The difference in cross-reactivities of molecular GH forms in polyclonal assays may have an impact on the correlation between plasma and urinary GH. Thus, the diagnostic value of urinary GH measurement as compared to serum GH profiles needs to be further evaluated.

Growth hormone status in six children with fetal alcohol syndrome

OBJECTIVE

Prenatal alcohol exposure may cause fetal alcohol syndrome (FAS), which is associated with pre- and postnatal retardation.

MATERIALS AND METHODS

Spontaneous 24-h growth hormone (GH) secretion was measured in six prepubertal short children with FAS (two boys and four girls) aged 4-14 years. The response to a GH stimulation test, and levels of insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 (IGFBP-3) were also measured. Comparisons were made between the children with FAS and healthy children of both normal and short stature, as well as children born small for gestational age (SGA).

RESULTS

There were no differences in the mean area under the curve above the baseline or the maximum level of GH during a 24-h period (GHmax) between the children with FAS and the reference groups. However, the estimated rate of spontaneous 24-h GH secretion in children with FAS was similar to that of children born SGA, but lower than in children of normal stature (p = 0.02). The plasma concentrations of IGF-I and IGFBP-3 were in the lower parts of the normal range.

CONCLUSION

We conclude that GH secretion in short children with FAS is similar to that in short children born SGA; that is, in the lower range of normal children.

Changes in serum insulin-like growth factor I (IGF-I) and IGF-binding protein-3 levels during growth hormone treatment in prepubertal short children born small for gestational age

The aims of this study were to describe the basal serum levels of insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) and to evaluate their changes during daily GH treatment (0.1 IU/kg; 33 micrograms/kg) for up to 2 yr in prepubertal short children born small for gestational age (SGA) and to correlate these changes with the growth response to GH therapy. Seventy-two prepubertal short children (height SD score, -5.4 to -2.0; age, 2.0-12.9 yr) born SGA (54 boys and 18 girls), eight of whom (six boys and two girls) had signs of Silver-Russell syndrome, participated in the study. The serum concentrations of IGF-I and IGFBP-3 were converted into SDS using our reference values for prepubertal healthy children. The mean (+/-SD) change in height SDS during the year before the start of GH treatment was 0.1 (0.2) and increased to 0.8 (0.4) during the first year (P < 0.001) and to 0.6 (0.3) during the second year of therapy (P < 0.001). Basal levels of both IGF-I and IGFBP-3 were significantly reduced compared with the reference values. The mean (+/-SD) basal serum concentration of IGF-I was -0.6 (1.1) SD score, and 80% of the SGA children had IGF-I levels below the 50th percentile of the reference group. The corresponding values for IGFBP-3 were -0.4 (1.0) SD score and 63%. The mean IGF-I level increased significantly by 55% from baseline to day 10 of treatment, by 76% on day 90, by 90% after 1 yr, and by 123% after 2 yr of GH treatment. The mean increases in IGFBP-3 were not as great: 25%, 27%, 35%, and 43%, respectively. The 1-yr growth response, expressed as the change in height SD score, correlated negatively with both the basal serum concentration of IGF-I (r = -0.37; P < 0.001) and IGFBP-3 (r = -0.35; P < 0.01), whereas a positive correlation was found to the 10-day percent increase in IGF-I (r = 0.32; P < 0.05). No correlations were found with the initial changes in IGFBP-3. Using a multiple stepwise linear regression analysis, the model using chronological age at the start of GH therapy, the mother's height expressed as a SD score, and the short term percent increase in IGF-I accounted for 42% of the variance in the 1-yr growth response. With the inclusion of 24-h GH profiles, 59% of the variability of the growth response could be explained. It is concluded that short prepubertal children born SGA show an increased growth rate in response to GH therapy. Their mean IGF-I and IGFBP-3 levels before treatment were low and correlated negatively with the growth response to treatment, indicating GH insufficiency. Finally, up to 59% of the variability in the 1-yr growth response to GH treatment could be explained by models using auxological and biochemical variables.

Constructed deletions in lumen-exposed regions of the D1 protein in the cyanobacterium Synechocystis 6803: Effects on D1 insertion and accumulation in the thylakoid membrane, and on Photosystem II assembly

Modified forms of the D1 protein with deletions in lumen-exposed regions, were constructed in the cyanobacterium Synechocystis 6803 using site-directed mutagenesis. Integration and stability of the mutated D1 proteins in the thylakoid membrane were studied by immunoblot and pulse-chase analyses. It was found that in Δ(N325-E333), the D1 protein with a deletion in the C-terminal tail, could insert in the thylakoids to normal amounts but its stability in the membrane was dramatically reduced. Insertion of D1 in Δ(V58-D61) or Δ(D103-G109);G110R, with deletions in the A-B loop, was severely obstructed, For Δ(P350-T354), with a deletion in the processed region of the C-terminus of D1, no phenotypic effects were observed. The effects of failed D1 insertion or accumulation on Photosystem II assembly was monitored by immunoblot analysis. The conclusions from these experiments are that the extrinsic 33 kDa protein, CP43, and the β subunit of cytochrome b559 accumulate in the thylakoid membrane independently of the D1 protein, and that accumulation of the D2 protein and CP47 requires insertion but not necessarily accumulation of the D1 protein.

A new dhfrVIII trimethoprim-resistance gene, flanked by IS26, whose product is remote from other dihydrofolate reductases in parsimony analysis

A new plasmid-borne gene, dhfrVIII, encoding high-level trimethoprim resistance (TpR) was found in an intestinal Escherichia coli. It seems to be a widely occurring mediator of TpR. Among 973 examined TpR E. coli, the new resistance gene was found in 13 (1.3%) isolates from Sweden, Finland and Nigeria. The new gene was sequenced and found to code for a dihydrofolate reductase (DHFR) of 169 amino acids (M(r) 19005). The dhfrVIII gene on the studied plasmid pLMO226 was observed to be flanked by IS26 elements. The dhfrVIII gene and a 3' unidentified open reading frame (ORF) seem to be borne on a compound transposon with IS26 at its ends, since the configuration of two IS26 flanking dhfrVIII and the unidentified ORF was conserved among the isolates that were probe-positive for the gene. Phylogeny parsimony analysis showed the dhfrVIII-encoded enzyme to be only remotely related to other known plasmid-mediated, drug-resistant DHFR. Only a few of the latter form well-supported monophyletic groups.