CRF binding protein activity in the hypothalamic paraventricular nucleus is essential for stress adaptations and normal maternal behaviour in lactating rats

To ensure the unrestricted expression of maternal behaviour peripartum, activity of the corticotropin-releasing factor (CRF) system needs to be minimised. CRF binding protein (CRF-BP) might be crucial for this adaptation, as its primary function is to sequester freely available CRF and urocortin1, thereby dampening CRF receptor (CRF-R) signalling. So far, the role of CRF-BP in the maternal brain has barely been studied, and a potential role in curtailing activation of the stress axis is unknown. We studied gene expression for CRF-BP and both CRF-R within the paraventricular nucleus (PVN) of the hypothalamus. In lactating rats, Crh-bp expression in the parvocellular PVN was significantly higher and Crh-r1 expression in the PVN significantly lower compared to virgin rats. Acute CRF-BP inhibition in the PVN with infusion of CRF(6-33) increased basal plasma corticosterone concentrations under unstressed conditions in dams. Furthermore, while acute intra-PVN infusion of CRF increased corticosterone secretion in virgin rats, it was ineffective in vehicle (VEH)-pre-treated lactating rats, probably due to a buffering effect of CRF-BP. Indeed, pre-treatment with CRF(6-33) reinstated a corticosterone response to CRF in lactating rats, highlighting the critical role of CRF-BP in maintaining attenuated stress reactivity in lactation. To our knowledge, this is the first study linking hypothalamic CRF-BP activity to hypothalamic-pituitary-adrenal axis regulation in lactation. In terms of behaviour, acute CRF-BP inhibition in the PVN under non-stress conditions reduced blanket nursing 60 min and licking/grooming 90 min after infusion compared to VEH-treated rats, while increasing maternal aggression towards an intruder. Lastly, chronic intra-PVN inhibition of CRF-BP strongly reduced maternal aggression, with modest effects on maternal motivation and care. Taken together, intact activity of the CRF-BP in the PVN during the postpartum period is essential for the dampened responsiveness of the stress axis, as well as for the full expression of appropriate maternal behaviour.

Neoadjuvant radiotherapy in ER+, HER2+, and triple-negative -specific breast cancer based humanized tumor mice enhances anti-PD-L1 treatment efficacy

Pre-operative radiation therapy is not currently integrated into the treatment protocols for breast cancer. However, transforming immunological "cold" breast cancers by neoadjuvant irradiation into their "hot" variants is supposed to elicit an endogenous tumor immune defense and, thus, enhance immunotherapy efficiency. We investigated cellular and immunological effects of sub-lethal, neoadjuvant irradiation of ER pos., HER2 pos., and triple-negative breast cancer subtypes in-vitro and in-vivo in humanized tumor mice (HTM). This mouse model is characterized by a human-like immune system and therefore facilitates detailed analysis of the mechanisms and efficiency of neoadjuvant, irradiation-induced "in-situ vaccination", especially in the context of concurrently applied checkpoint therapy. Similar to clinical appearances, we observed a gradually increased immunogenicity from the luminal over the HER2-pos. to the triple negative subtype in HTM indicated by an increasing immune cell infiltration into the tumor tissue. Anti-PD-L1 therapy divided the HER2-pos. and triple negative HTM groups into responder and non-responder, while the luminal HTMs were basically irresponsive. Irradiation alone was effective in the HER2-pos. and luminal subtype-specific HTM and was supportive for overcoming irresponsiveness to single anti-PD-L1 treatment. The treatment success correlated with a significantly increased T cell proportion and PD-1 expression in the spleen. In all subtype-specific HTM combination therapy proved most effective in diminishing tumor growth, enhancing the immune response, and converted non-responder into responder during anti-PD-L1 therapy. In HTM, neoadjuvant irradiation reinforced anti-PD-L1 checkpoint treatment of breast cancer in a subtype -specific manner. According to the "bench to bedside" principle, this study offers a vital foundation for clinical translating the use of neoadjuvant irradiation in the context of checkpoint therapy.

Immune Checkpoint Profiling in Humanized Breast Cancer Mice Revealed Cell-Specific LAG-3/PD-1/TIM-3 Co-Expression and Elevated PD-1/TIM-3 Secretion

Checkpoint blockade is particularly based on PD-1/PD-L1-inhibiting antibodies. However, an efficient immunological tumor defense can be blocked not only by PD-(L)1 but also by the presence of additional immune checkpoint molecules. Here, we investigated the co-expression of several immune checkpoint proteins and the soluble forms thereof (e.g., PD-1, TIM-3, LAG-3, PD-L1, PD-L2 and others) in humanized tumor mice (HTM) simultaneously harboring cell line-derived (JIMT-1, MDA-MB-231, MCF-7) or patient-derived breast cancer and a functional human immune system. We identified tumor-infiltrating T cells with a triple-positive PD-1, LAG-3 and TIM-3 phenotype. While PD-1 expression was increased in both the CD4 and CD8 T cells, TIM-3 was found to be upregulated particularly in the cytotoxic T cells in the MDA-MB-231-based HTM model. High levels of soluble TIM-3 and galectin-9 (a TIM-3 ligand) were detected in the serum. Surprisingly, soluble PD-L2, but only low levels of sPD-L1, were found in mice harboring PD-L1-positive tumors. Analysis of a dataset containing 3039 primary breast cancer samples on the R2 Genomics Analysis Platform revealed increased TIM-3, galectin-9 and LAG-3 expression, not only in triple-negative breast cancer but also in the HER2⁺ and hormone receptor-positive breast cancer subtypes. These data indicate that LAG-3 and TIM-3 represent additional key molecules within the breast cancer anti-immunity landscape.

Advanced Immune Cell Profiling by Multiparameter Flow Cytometry in Humanized Patient-Derived Tumor Mice

"Humanized" mice have been widely used for the characterization of human cancer progression and as a powerful preclinical model. Standardization of multicolor phenotyping could help to identify immune cell patterns involved in checkpoint-related complications. Therefore, we applied established protocols for immune cell profiling to our humanized Patient-Derived Xenograft (hPDX) model. hPDX are characterized by the co-existence of a human immune system and a patient-derived tumor transplant. These mice possess a human-like immune system after CD34⁺ stem cell transplantation while the reconstitution level of the immune system was not related to the quantity of transplanted CD34⁺ cells. Contamination ≤ 1.2% by CD3⁺ cells in the hematopoietic stem cell (HSC) transplant did not trigger abnormal T cell maturation. Different B and T cell differentiation stages were identified, as well as regulatory T cells (Tregs) and exhausted T cells that expressed TIGIT, PD-1, or KLRG1. Overall, the application of standardized protocols for the characterization of immune cells using flow cytometry will contribute to a better understanding of immune-oncologic processes.

Epidermal changes during UVB phototherapy assessed by multiphoton laser tomography

BACKGROUND

Multiphoton laser tomography (MPT) is a non-invasive technique that allows imaging of skin in vivo with very high spatial resolution and contrast. Previous work of our group has demonstrated that known morphological changes due to erythematogenic ultraviolet B (UVB) irradiation may be imaged in vivo by MPT. The present work investigated if morphological skin changes known from experimental erythematogenic UVB irradiation are also demonstrable in the course of a standard phototherapy regime that implies suberythematogenic doses of narrow band UVB.

METHODS

Sixteen patients with psoriasis vulgaris receiving a narrow band phototherapy were included. A test field and a light-protected control field were measured with the multiphoton tomograph DermaInspect^® at four time points: at baseline, the next day, after 3 days and at the day of the last exposure.

RESULTS

In the course of the UVB phototherapy, spongiosis and pleomorphy as parameters of inflammation and cellular damage did not show significant changes. By contrast, an adaptive skin reaction with significant changes of keratosis and pigmentation was observed.

CONCLUSION

MPT is a suitable technique for the investigation of qualitative and quantitative skin changes after UVB irradiation. After suberythematogenic UVB irradiation, photoadaptive skin changes, but no cellular damage can be observed with MPT.

To what extent does urbanisation affect fragmented grassland functioning?

Urbanisation creates altered environments characterised by increased human habitation, impermeable surfaces, artificial structures, landscape fragmentation, habitat loss, resulting in different resource loss pathways. The vulnerable Rand Highveld Grassland vegetation unit in the Tlokwe Municipal area, South Africa, has been extensively affected and transformed by urbanisation, agriculture, and mining. Grassland fragments in urban areas are often considered to be less species rich and less functional than in the more untransformed or "natural" exurban environments, and are therefore seldom a priority for conservation. Furthermore, urban grassland fragments are often being more intensely managed than exurban areas, such as consistent mowing in open urban areas. Four urbanisation measures acting as indicators for patterns and processes associated with urban areas were calculated for matrix areas surrounding each selected grassland fragment to quantify the position of each grassland remnant along an urbanisation gradient. The grassland fragments were objectively classified into two classes of urbanisation, namely "exurban" and "urban" based on the urbanisation measure values. Grazing was recorded in some exurban grasslands and mowing in some urban grassland fragments. Unmanaged grassland fragments were present in both urban and exurban areas. Fine-scale biophysical landscape function was determined by executing the Landscape Function Analysis (LFA) method. LFA assesses fine-scale landscape patchiness (entailing resource conserving potential and erosion resistance) and 11 soil surface indicators to produce three main LFA parameters (stability, infiltration, and nutrient cycling), which indicates how well a system is functioning in terms of fine-scale biophysical soil processes and characteristics. The aim of this study was to determine the effects of urbanisation and associated management practices on fine-scale biophysical landscape function of urban and exurban grassland fragments, as well as to determine the potential for the use of LFA in decision-making involving the conservation of grassland fragments. The results indicated that the occurrence, size and characteristics of vegetated patches, and especially the presence of litter abundances, were the main factors determining differences in the LFA indices. Furthermore, mowing resulted in the overall fine-scale biophysical indices being higher for some of the urban grassland fragments. This implied that it is not necessarily the influence of urbanisation entailing high or low resource conserving patchiness and patch quality, but rather the management practices associated with urban and exurban areas. Therefore, from a conservation point of view, the grassland fragments in the City of Potchefstroom are just as conservable (on a biophysical function level involving soil processes) than the more "natural" exurban grassland fragments.

Acute UVB-induced epidermal changes assessed by multiphoton laser tomography

BACKGROUND

In vivo multiphoton tomography (MPT) of human skin has become a valuable tool for non-invasive examination of morphological and biophysical skin properties and their alterations. So far, skin changes after UVB irradiation were mainly evaluated clinically and histologically. The present study aimed at non-invasive imaging of histological changes during acute UVB irradiation by multiphoton laser tomography.

METHODS

In 10 volunteers, five areas were irradiated once with an erythematous UVB dose. Multiphoton measurements were performed four times, i.e. before irradiation (baseline), and 24, 48 and 72 h after irradiation, respectively. The data were evaluated for changes of epidermal pleomorphy, spongiosis, pigmentation and thickness.

RESULTS

The four parameters were altered significantly by acute UVB irradiation, i.e. epidermal pleomorphy, spongiosis, pigmentation and thickness increased within 72 h after irradiation.

CONCLUSION

Thus, the study has shown that typical epidermal changes induced by acute UVB irradiation can be evaluated by MPT.

Landscape functionality of plant communities in the Impala Platinum mining area, Rustenburg

The tremendous growth of the platinum mining industry in South Africa has affected the natural environment adversely. The waste produced by platinum mineral processing is alkaline, biologically sterile and has a low water-holding capacity. These properties in the environment may constitute dysfunctional areas that will create 'leaky' and dysfunctional landscapes, limiting biological development. Landscape Function Analysis (LFA) is a monitoring procedure that assesses the degradation of landscapes, as brought about by human, animal and natural activities, through rapidly assessing certain soil surface indicators which indicate the biophysical functionality of the system. The "Trigger-Transfer-Reserve-Pulse" (TTRP) conceptual framework forms the foundation for assessing landscape function when using LFA. The two main aspects of this framework are the loss of resources from the system and the utilisation of resources by the system. After a survey of landscape heterogeneity to reflect the spatial organisation of the landscape, soil surface indicators are assessed within different patch types (identifiable units that retains resources that pass through the system) and interpatches (units between patches where vital resources are not retained, but lost) to assess the capacity of patches with various physical properties in regulating the effectiveness of resource control in the landscape. Indices describing landscape organisation are computed by a spreadsheet analysis, as well as soil surface quality indices. When assembled in different combinations, three indices emerge that reflect soil productive potential, namely: the (1) surface stability, (2) infiltration capacity, and (3) the nutrient cycling potential of the landscape. In this study we compared the landscape functionality of natural thornveld areas, rehabilitated opencast mines and rehabilitated slopes of tailings dams in the area leased for mining in the Rustenburg area. Our results show that the rehabilitated areas had a higher total SSA functionality due to higher infiltration and nutrient cycling indices than the natural thornveld landscapes. The length of interpatches and the width of patches greatly influenced the landscape function of the studied areas. The natural thornveld areas had a marginally higher total patch area than the rehabilitated areas. Vegetated patches (grass-, sparse grass-, grassy forb-, and grassy shrub-patches) generally scored the highest functionality indices, whilst bare soil interpatches contributed to the landscape functionality of the various plant communities the least.

Unlike αβ T cells, γδ T cells, LTi cells and NKT cells do not require IRF4 for the production of IL-17A and IL-22

Apart from conventional CD4(+) Th17 cells, the cytokines IL-17A and IL-22 can also be produced by γδ T cells, NK cells and lymphoid tissue inducer (LTi) cells. Th17 cells develop from precursor cells after T-cell receptor stimulation in the presence of TGF-β, IL-6 and IL-23. In contrast, a subset of γδ T cells ("γδT17") is committed for fast IL-17 production already in the thymus; however, γδ T cells can also produce IL-17 after prolonged in vitro stimulation via their γδ T-cell receptor plus IL-23. Here, we show that γδ T-, LTi- and NKT cells differ extensively from Th17 cells in their signalling requirements for the generation of IL-17A and IL-22. While production of these cytokines by Th17 cells totally depends on the transcription factor interferon regulatory factor 4 (IRF4), IRF4 is irrelevant in the other cell types. As for γδ T cells, this finding pertains to both thymic commitment and prolonged in vitro culture. Furthermore, IL-17A-producing γδ T cells accumulate in the central nervous system of IRF4 deficient (Irf4(-/-)) mice during experimental autoimmune encephalomyelitis. IL-17A-producing WT and Irf4(-/-) γδ T cells equally express CCR6 and lack CD27. The underlying IRF4-independent pathway partially involves STAT3 during in vitro stimulation.

Sex at the margins: parthenogenesis vs. facultative and obligate sex in a Neotropical ant

Geographic parthenogenesis is a distribution pattern, in which parthenogenetic populations tend to live in marginal habitats, at higher latitudes and altitudes and island-like habitats compared with the sexual forms. The facultatively parthenogenetic ant Platythyrea punctata is thought to exhibit this general pattern throughout its wide range in Central America and the Caribbean Islands. Workers of P. punctata from the Caribbean produce diploid female offspring from unfertilized eggs by thelytokous parthenogenesis, and mated females and males are rare. In contrast, workers in one colony from Costa Rica were incapable of thelytoky; instead mated workers produced all female offspring. Because sample sizes were very low in former studies, we here use microsatellite markers and explicit tests of thelytoky to examine the population genetic structure of ancestral and derived populations of P. punctata throughout the Caribbean and Central America. Populations from the Caribbean islands were fully capable of parthenogenesis, and population genetic signatures indicate that this is the predominant mode of reproduction, although males are occasionally produced. In contrast, the northernmost population on the mainland (Texas) showed signatures of sexual reproduction, and individuals were incapable of reproduction by thelytoky. Contrary to expectations from a geographic parthenogenesis distribution pattern, most parts of the mainland populations were found to be facultatively thelytokous, with population genetic signatures of both sexual and parthenogenetic reproduction.

Transcription factor IRF4 determines germinal center formation through follicular T-helper cell differentiation

Follicular T-helper (T(FH)) cells cooperate with GL7(+)CD95(+) germinal center (GC) B cells to induce antibody maturation. Herein, we identify the transcription factor IRF4 as a T-cell intrinsic precondition for T(FH) cell differentiation and GC formation. After immunization with protein or infection with the protozoon Leishmania major, draining lymph nodes (LNs) of IFN-regulatory factor-4 (Irf4(-/-)) mice lacked GCs and GC B cells despite developing normal initial hyperplasia. GCs were also absent in Peyer's patches of naive Irf4(-/-) mice. Accordingly, CD4(+) T cells within the LNs and Peyer's patches failed to express the T(FH) key transcription factor B-cell lymphoma-6 and other T(FH)-related molecules. During chronic leishmaniasis, the draining Irf4(-/-) LNs disappeared because of massive cell death. Adoptive transfer of WT CD4(+) T cells or few L. major primed WT T(FH) cells reconstituted GC formation, GC B-cell differentiation, and LN cell survival. In support of a T-cell intrinsic IRF4 activity, Irf4(-/-) T(FH) cell differentiation was not rescued by close neighborhood to transferred WT T(FH) cells. Together with its known B lineage-specific roles during plasma cell maturation and class switch, our study places IRF4 in the center of antibody production toward T-cell-dependent antigens.

Identification of Ras, Pten and p70S6K homologs in the Pacific oyster Crassostrea gigas and diet control of insulin pathway

Insulin pathways were demonstrated from invertebrates to vertebrates to be involved in the regulation of numerous processes including storage metabolism and reproduction. In addition, insulin system may integrate variations of environmental conditions like dietary restrictions. In the Pacific oyster Crassostrea gigas, reproductive and storage compartments are closely intricated in the gonadal area and their respective development was found to be dependant of trophic conditions. For these reasons, C. gigas is an original and interesting model for investigating the role of insulin control in the balance between storage and reproduction and the integration of environmental parameters. On the basis of sequence conservation, we identified three potential elements of the oyster insulin pathway, Ras, Pten and p70S6K and we investigated their expression levels in various tissues. In the gonadal area, we used laser microdissection in order to precise the targeted contribution of insulin signaling to the restoration of storage tissue and to the control of vitellogenesis. Food deprivation during gametogenesis reinitiation stage led to reduced proliferations of gonia and also to modulate insulin signal by transcriptional activation of insulin pathway elements.

Recruitment of host translation initiation factor eIF4G by the Vaccinia Virus ssDNA-binding protein I3

Poxviruses are large double-stranded DNA viruses that replicate exclusively in the cytoplasm of infected cells within discrete compartments termed viral factories. Recent work has shown that the prototypical poxvirus, Vaccinia Virus (VacV) sequesters components of the eukaryotic translation initiation complex eIF4F within viral factories while also stimulating formation of eIF4F complexes. However, the forces that govern these events remain unknown. Here, we show that maximal eIF4F formation requires viral DNA replication and the formation of viral factories, suggesting that sequestration functions to promote eIF4F assembly, and identify the ssDNA-binding protein, I3 as a viral factor that interacts and co-localizes with the eIF4F scaffold protein, eIF4G. Although it did not adversely affect host or viral protein synthesis, I3 specifically mediated the binding of eIF4G to ssDNA. Combined, our findings offer an explanation for the specific pattern and temporal process of eIF4G redistribution and eIF4F complex assembly within VacV-infected cells.

A target-orientated algorithm for regional citrate-calcium anticoagulation in extracorporeal therapies

BACKGROUND

Citrate anticoagulation offers several advantages in comparison to conventional anticoagulation. Most algorithms for regional citrate-calcium anticoagulation are based on citrate and calcium chloride infusion coupled in a fixed proportion to the blood flow without considering the hematocrit (Hct)/plasma flow or the filter clearance of citrate and calcium.

METHODS

The aim of this study was to develop an algorithm for optimized citrate anticoagulation in extracorporeal therapies such as dialysis. A mathematical model was developed to calculate the volume of citrate infusion required to achieve a desired ionized calcium (iCa) target level in the extracorporeal circuit and to restore the total calcium level to a physiological value.

RESULTS

The model was validated by correlation analyses for different blood Hct values and shows an excellent fit to the laboratory measurements.

CONCLUSION

The results for both iCa target concentrations, namely those after citrate and calcium infusion, proved that the software algorithm adapts well to variable treatment parameters.

Polygyny and polyandry in small ant societies

Social insects, ants in particular, show considerable variation in queen number and mating frequency resulting in a wide range of social structures. The dynamics of reproductive conflicts in insect societies are directly connected to the colony kin structure, thus, the study of relatedness patterns is essential in order to understand the evolutionary resolution of these conflicts. We studied colony kin structure and mating frequencies in two closely related Neotropical ant species Pachycondyla inversa and Pachycondyla villosa. These represent interesting model systems because queens found new colonies cooperatively but, unlike many other ant species, they may still co-exist when the colony becomes mature (primary polygyny). By using five specific and highly variable microsatellite markers, we show that in both species queens usually mate with two or more males and that cofounding queens are always unrelated. Polygynous and polyandrous colonies are characterized by a high genetic diversity, with a mean relatedness coefficient among worker nestmates of 0.27 (+/- 0.03 SE) for P. inversa and 0.31 (+/- 0.05 SE) for P. villosa. However, relatedness among workers of the same matriline is high (0.60 +/- 0.03 in P. inversa, 0.62 +/- 0.08 in P. villosa) since males that mated with the same queen are on average closely related. Hence, we have found a new taxon in social Hymenoptera with high queen-mating frequencies and with intriguing mating and dispersal patterns of the sexuals.

Cryopreservation of Crassostrea gigas vesicular cells: Viability and metabolic activity

Cryopreservation is widely used for long-term conservation of various tissues, embryos or gametes. However, few studies have described cryopreservation of invertebrate primary cell cultures and more particularly of marine invertebrate somatic cells. This technique would however be of great interest to facilitate the study of various metabolic processes which vary seasonally. The aim of the present study was to develop a protocol for cryopreservation of Crassostrea gigas vesicular cells. Different parameters were adjusted to improve recovery of cells after freezing. The most efficient cryoprotectant agent was a mix of Me(2)SO, glycerol, and ethylene glycol (4% each). The optimal cooling rate was -1 degrees Cmin(-1) down to -70 degrees C before transfer into liquid nitrogen. In these conditions the percentage of viable cells reached 70% of the control. The glucose metabolism of thawed cells was evaluated using radioactive glucose as a tracer. Immediately after thawing, glucose uptake involving membrane transporters was greatly reduced (24% of control) whereas glucose incorporation into glycogen was less affected (68% of control).

Land user participation in developing a computerised decision support system for combating desertification

Combating desertification in natural rangelands has recently become a priority in large parts of southern Africa. Rangeland managers, farmers, scientists, conservationists and land users have been applying a variety of restoration technologies to address this problem. Bush encroachment, as part of the desertification process, involves the natural replacement of the herbaceous plant cover by undesirable problem woody species. The active and passive restoration technologies that are applied, are mainly based on indigenous knowledge and include the chemical, mechanical or manual reclamation of unproductive rangelands, as well as the combating of woody and alien species encroachment. Indigenous practices and knowledge play a major role in the effectiveness and success rate of these technologies. This project faces the challenge of bringing together both local and scientific knowledge in a single user-friendly, computerised Decision Support System (DSS) which is directly accessible by land users to support them in the process of decision making, concerning the combating of desertification. Case studies from central and northern Namibia were used to combine qualitative and quantitative data to develop this Decision Support System. The DSS currently consists of two databases and an expert system, which evaluates the results of land users' management practices, and provides easily accessible information and advice for participants in the system, based on the incorporated data. The DSS is also linked to national and international web sites and databases to offer a wider range of information on technologies concerning agricultural and conservation practices.

Trichloroacetic acid as additional factor contributing to desertification in southern Africa

There has been an accelerated expansion of deserts in the past five decades. Recent data reveal that the atmogenically formed organic compound, trichloroacetic acid (TCA) is a contributory factor in addition to anthropogenic and natural sources. The aim of this study was to use TCA as an indicator for the possible occurrence of C2-chloroacetic acids; to assess the burden on the vegetation by using pine needles as a bio-indicator system and to deliberate on the possible role of TCA in the dynamics of the vegetation in southern Africa. Field experiments conducted on pine trees and on C3 and C4 crop plants under controlled laboratory conditions, have revealed that plants could be influenced positively or negatively by TCA. To obtain an integrated assessment of the pollution emission over a time span of at least one year, two-year-old pine needles of different Pinus species were used as a bio-indicator for TCA pollution at different measuring sites. The data of our investigation clearly indicate that areas exist in South Africa where the vegetation is burdened by ecotoxicologically relevant TCA contents comparable to those in central Europe and southern Russia where TCA was shown to play a role in the destabilisation of the steppe vegetation.

Analysis of the riparian vegetation (Ia land type) of the proposed Vhembe-Dongola National Park, Limpopo Province, South Africa

The establishment of the Vhembe-Dongola National Park has been an objective of several conservationists for many years. The ultimate objective is that this park would become a major component of a transfrontier park shared by Botswana, Zimbabwe and South Africa. The aim of this study was to identify, classify and describe the plant communities present in the Ia land type of the proposed area for the park. Sampling was done by means of the Braun-Blanquet method. A total of 70 stratified random relevés were sampled in the Ia land type. All relevé data was imported into the database TURBOVEG after which the numerical classification technique TWINSPAN was used as a first approximation. Subsequently Braun-Blanquet procedures were used to refine data and a phytosociological table was constructed, using the visual editor, MEGATAB. From the phytosociological table four plant communities were identified and described in the Ia land type. The ordination algorithm, DECORANA, was applied to the floristic data in order to illustrate floristic relationships between plant communities, to detect possible gradients in and between communities and to detect possible habitat gradients and/or disturbance gradients associated with vegetation gradients.

Insulin-like system and growth regulation in the Pacific oyster Crassostrea gigas: hrIGF-1 effect on protein synthesis of mantle edge cells and expression of an homologous insulin receptor-related receptor

The involvement of molecules belonging to the insulin/IGF family in regulation of growth has been investigated in the Pacific oyster Crassostrea gigas. In vitro biological effects of human recombinant IGF-1 (hrIGF-1) on mantle edge cells, involved in oyster shell and soft body growth, were studied over an annual cycle. In mantle edge cells hrIGF-1 stimulates protein synthesis of 56+/-5.1% over basal for 10(-10) M in September with in addition a clear dose-effect corresponding to the highest shell growth period, and 57.5+/-3.45% over basal for 10(-11) M in March and 51+/-5.4% over basal for 10(-10) M in April corresponding to the period of mantle growth. These insulin-like effects were associated with the expression of a recently identified C. gigas insulin receptor-related receptor (CIR) in mantle edge cells as demonstrated by RT-PCR. Moreover, in situ hybridisation (ISH) confirmed this expression at the level of the inner and outer epithelia involved in mantle growth and shell formation.

Insulin in tissue engineering of cartilage: a potential model system for growth factor application

Investigation of novel experimental application systems for growth factors or other bioactive substances in tissue engineering is often limited by high costs of substances and would benefit from a defined and easily controllable model tissue system. Herein, we demonstrate a potential three-dimensional in vitro system using engineered cartilage as a model tissue and readily available insulin as a model drug. Previously it has been shown that insulin-like growth factor-I (IGF-I) has profound effects on tissue-engineered cartilage in vitro. Insulin is known to bind to the IGF-I receptor and to elicit significant responses in cartilage. In this study, bovine articular chondrocytes were seeded onto biodegradable polyglycolic acid (PGA) scaffolds and cultured for up to 7 weeks. Exogenous insulin (0.05-50 microg/ml) increased the growth rate and the glycosaminoglycan fraction of tissue-engineered cartilage, decreased the cell number in the tissue constructs, and improved the morphological appearance, with 2.5 microg/ml being the most favorable concentration. The observed effects of insulin were similar to effects of IGF-I (0.05 microg/ml) and were in agreement with the reported binding constants of IGF-I and insulin at the IGF-I receptor. Besides the possibility to employ insulin as a potent substance to improve tissue-engineered cartilage, the presented easily controllable in vitro system may be used in the future to evaluate experimental growth factor application devices using economically favorable insulin as a model protein.

Different expression of endothelin in the bronchoalveolar lavage in patients with pulmonary diseases

Endothelin (ET) is a broncho- and vasoconstrictive cytokine, but it also possesses proinflammatory and mitogenic activity. It is suggested to be involved in the pathogenesis of fibrotic lung diseases. We analyzed the concentration of ET 1 in the bronchoalveolar lavage (BAL) fluid in 95 patients with different lung diseases, among them 41 patients with interstitial lung diseases (13 fibrosing alveolitis in systemic sclerosis (FASS), 9 idiopathic pulmonary fibrosis (IFP), 8 sarcoidosis (S), 6 occupational lung disease (OLD), 5 other alveolitidies A), 27 patients with pneumonia, and 8 patients with chronic obstructive pulmonary disease (COPD). A heterogeneous group of 19 patients served as controls. The median ET concentration was 3.3 pg/ml. Significantly higher concentration was found in patients with FASS (5.8 pg/ml), IPF (5.0 pg/ml), and S (5.1 pg/ml) compared with OLD (2.8 pg/ml), A (1.9 pg/ml), COPD (1.5 pg/ml), and the control group (2.5 pg/ml). In pneumonia, the elevated ET concentration (4.1 pg/ml) was accompanied by a high alveolocapillary leakage. When normalized to BAL albumin concentration, only FASS presented with significantly elevated ET/albumin in the BAL compared with the control group (134.5 vs. 56.l pg/mg, p < 0.05). There were no correlations between ET and BAL differential cell count or pulmonary function tests. In current smokers, ET in BALF was significantly higher compared with non- or ex-smokers (3.9 vs. 2.0 pg/ml, p < 0.01), but not so the ET/albumin ratio (65.0 vs. 62.5 pg/mg). In summary, ET in the BAL is differentially expressed in distinct inflammatory and interstitial lung disease. Consistently high concentrations are found in FASS and elevated ET concentration could be discussed in IPF, sarcoidosis, and pneumonia. ET concentration in BAL is influenced by current smoking habits.

Immunocytochemical demonstration of glucagon-like peptides in Mytilus edulis cerebral ganglia and an in vitro effect of vertebrate glucagon on glycogen metabolism

Immunological detection of glucagon-like peptides was performed in the cerebral ganglia of the mussel Mytilus edulis using an anti-vertebrate glucagon antibody. Two clusters of positive neurosecretory cells were observed, as well as stained nervous fibers. The effect of vertebrate glucagon on glucose incorporation into glycogen of reserve cells was tested using an in vitro microplate bioassay. Optimal incubation conditions were previously defined and an inhibitory effect of porcine glucagon was obtained for concentrations ranging from 10(-6) to 10(-9)M. It is postulated that the glucagon-like peptide may be implicated in the regulation of glucose metabolism in bivalves.

Severe hypoglycemia due to insulin autoimmune syndrome with insulin autoantibodies crossreactive to proinsulin

We report the case of a 69-year-old woman with insulin autoimmune syndrome first misdiagnosed as insulinoma. The case demonstrates the difficulties to correctly diagnose this rare disorder as both insulin and proinsulin levels were increased by crossreactive autoantibodies. No known triggering agent could be identified. We suggest that this diagnosis should be considered more often also in caucasian patients to avoid useless operations for such patients.

Titre and combination of ICA and autoantibodies to glutamic acid decarboxylase discriminate two clinically distinct types of latent autoimmune diabetes in adults (LADA)

ABSTRACT AIMS/HYPOTHESIS: This study aimed to define the immunological parameters which could be used to identify patients with the distinct metabolic features of adult latent autoimmune diabetes.

METHODS

Sera of 312 patients with short-term diabetes (duration < 5 years) over 35 years of age at diagnosis were screened for ICA, GAD- and IA2-Ab by antibody assays validated in workshops. The antibody status was correlated with age, BMI, residual beta-cell function, measured by fasting C-peptide, onset of diabetes-related complications and markers of the metabolic syndrome (hypertension and hyperlipidaemia).

RESULTS

A total of 51 antibody positive patients were identified. These patients had lower fasting C-peptide and less neuropathy and hypertension compared with matched antibody-negative patients. However, only patients with two or more antibodies had reduced residual beta-cell function compared with antibody-negative or single antibody-positive (ICA or GAD-Ab only) patients. Patients with two or more antibodies were also leaner and had diabetes-related complications or hypertension less frequently than single antibody-positive or antibody negative-patients. IA2 antibody status did not substantially contribute to the diagnosis or differentiation of LADA patients.

CONCLUSION/INTERPRETATION

We concluded that the combination of ICA and GAD antibodies and high titre of GAD antibodies are characteristic of patients with insulin deficiency with the clinical features of Type I (insulin-dependent) diabetes mellitus (LADA-type 1). Single antibody positivity and low titre antibodies are markers for LADA-type 2 associated with the clinical and metabolic phenotype of Type II (non-insulin-dependent) diabetes patients.

Characterization of a cDNA encoding a 72 kDa heat shock cognate protein (Hsc72) from the Pacific oyster, Crassostrea gigas

A full-length cDNA encoding a 72 kDa heat shock cognate protein (Hsc72) was isolated from a Crassostrea gigas hemocyte library. This cDNA is 75% identical to a human hsc70 cDNA. C. gigas cDNA contains a 659 amino acid open reading frame encoding a 72 kDa protein which is 87% identical to a human Hsc70 protein. Northern blotting indicated that even if the hsc72 gene was constitutively expressed in oyster hemocytes, it could be stimulated by heat shock in vitro as well as in vivo. Homologies observed both at the cDNA and protein levels, as well as the expression pattern of the hsc72 mRNA, support our conclusion that the isolated cDNA clone corresponds to an oyster heat shock cognate gene.

Storage metabolism in the Pacific oyster (Crassostrea gigas) in relation to summer mortalities and reproductive cycle (west coast of France)

We describe seasonal changes in the biochemical composition of digestive gland, adductor muscle and gonad and surrounding mantle area in Crassostrea gigas from the Western Atlantic coast of France. Seasonality in histology of storage tissues and glycogen storage capacity in isolated vesicular cells were also studied. Proteins, the main muscle components did not contribute to the gametogenetic effort. Glycogen and lipids were stored in the digestive gland, gonad and surrounding mantle area during the wintering period and the gonad and surrounding mantle area represented the main storage compartment supplying the reproductive effort. Gametogenesis in spring and summer was associated with an increase in lipid and protein contents and took place at the expense of glycogen reserves. Histological study of storage tissue in the gonad led us to define four seasonal stages of storage tissue development. In vitro, glycogen storage capacity in isolated vesicular cells was high from November to March and markedly reduced during gametogenesis, decreasing below detectable levels after spawning. This physiological state should be taken into account with relation to summer mortalities occurring in commercial growing areas.

Histological Characterization and Glucose Incorporation into Glycogen of the Pacific Oyster Crassostrea gigas Storage Cells

In order to investigate glycogen metabolism in the oyster Crassostrea gigas, the distribution of storage cells in the whole animal was studied before histological and biochemical characterization. These cells were found mainly in the labial palps, the mantle, and gonadal area and also in gills and the digestive area. Storage cells from palps, mantle, and gonad presented the same morphological features and the same seasonal glycogen variations. Storage cells were isolated from the labial palps and the mantle plus gonadal area of the oyster by enzymatic dispersion and centrifugation through discontinuous Percoll gradient. These cells have a modal density of 1.043 g/ml. An ultrastructural study confirmed that glycogen is present in the cytoplasm either as fine particles or sequestered within vesicles. Glucose incorporation into glycogen was evaluated in vitro using [U-(14)C]glucose: the incorporation in isolated cells increased linearly for at least 8 hours, was proportional to the cell concentration, and showed saturation kinetics with respect to the exogenous glucose concentration.

Dissociation of serum leptin concentration and body fat content during long term dietary intervention in obese individuals

High serum leptin concentrations are observed in humans with high body fat content, indicating leptin resistance. Reducing leptin levels by lowering body fat could restore leptin sensitivity. Our study was designed to clarify the relationship between changes in body composition and circulating leptin during a long term hypocaloric diet. 12 obese women and 10 obese men were included in a 1000 kcal/day dietary intervention trial for 10 weeks. Body composition was measured by body impedance analysis and leptin by radioimmunoassay every 2 weeks. Body fat was reduced in females from 39.0 +/- 1.5 kg to 32.9 +/- 1.5 kg (p <0.001) and in males from 30.4 1.4 kg to 26.3 +/- 1.3 kg (p < 0.005). Plasma leptin decreased in females from 38.07 +/- 4.17 ng/ml to 18.90 +/- 2.75 ng/ml (p < 0.001) and in males from 10.58 +/- 2.16 ng/ml to 6.33 +/- 1.25 ng/ml (p < 0.001). Non-linear regression analysis of leptin kinetics showed a comparable one-phase exponential decline (y = Span x e(-K x x) + Plateau) in females (x +/- SEM: K = 0.48 +/- 0.01) and males (K = 0.60 +/- 0.01). Kinetics of body fat differed significantly from leptin data for females (K = 0.10 +/- 0.001, p < 0.001) but not for males (K = 0.27 +/- 0.02, p > 0.05). The leptin plateau was reached in both groups after 6- 8 weeks and the fat plateau in men after 10 weeks. Compared to healthy controls, some obese individuals had higher absolute values of leptin, but seemed to have a relative leptin deficiency when leptin was adjusted to body mass index according to a non-linear regression model of a large group of healthy women (n = 561) and men (n = 393). We conclude that during a long-term hypocaloric diet leptin uncouples from changes in body fat mass.

K(+)-, hypoosmolarity-, and NH4(+)-induced taurine release from cultured rabbit Müller cells: role of Na+ and Cl- ions and relation to cell volume changes

The release of preloaded radiolabeled taurine (TAU) from cultured rabbit Müller cells [14-21 days in vitro (DIV)] was measured before and after treatment with the following stimuli: 1) isoosmotic 65 mM KCl; 2) a medium made hypoosmotic by uncompensated lowering of Na+ by 40-100 mM; and 3) NH4Cl ranging from 0.25 to 5 mM. The same stimuli were tested for their effect on the cell volume by the 3-O-methyl-D-glucose (OMG) uptake method of Kletzien et al. (Anal Biochem 68:537, 1975). Hypoosmotic media and 65 mM KCl stimulated TAU release, and the release was well correlated with the increase of cell volume. The stimulatory effect of 65 mM KCl was abolished by isotonic removal of Cl- or Na+, and omission of either ion markedly enhanced the basal release of TAU. The results are roughly consistent with the characteristics of the swelling-induced TAU release reported for cultured astrocytes and neurons of various CNS regions, and also for freshly isolated, nondissociated retina. Taken together, the results are indicative of a significant role of TAU release from Müller cells, in the osmosensory response of the retina. Ammonium chloride stimulated TAU release in a dose-dependent manner, a significant stimulation being already observed at 0.5 mM, a concentration that is frequently measured in brain during acute hyperammonemia. The effect of NH4Cl was strictly chloride dependent at 0.5-2 mM, but partly Cl- independent at 5 mM. The Kletzien's method did not appear to be well suited for measuring cell volume in the presence of ammonium ions.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined high-efficiency hemodialysis and charcoal hemoperfusion in severe N-acetylprocainamide intoxication

Several extracorporeal techniques have been used to remove N-acetylprocainamide (NAPA), the major metabolite of procainamide, in patients intoxicated with this substance. We report a patient with life-threatening NAPA intoxication who was rapidly and successfully treated with combined high-efficiency hemodialysis and charcoal hemoperfusion. The hemodialyzer and hemoperfusion cartridge were placed in series such that the patient's blood was dialyzed before reaching the cartridge. Overall clearance of NAPA was 153 mL/min, with clearance due to hemodialysis averaging 102 mL/min and that due to hemoperfusion averaging 88 mL/min. Thus, addition of the hemoperfusion cartridge into the extracorporeal circuit resulted in a 50% increase in clearance over that obtainable by high-efficiency hemodialysis alone. In comparison to other modalities, this technique is more effective than either hemodialysis or charcoal hemoperfusion alone and can achieve a more rapid reduction of serum NAPA levels than that observed with slow continuous hemofiltration or hemodiafiltration.

[Does the calcium antagonist verapamil modify calcium metabolism?]

In 11 healthy volunteers the effects of oral verapamil administration (4 X 80 mg/d) on plasma or serum concentrations of ionized, pH-corrected ionized and total calcium, on intact and midregional parathyroid hormone and on 24 h urinary excretion of calcium were investigated at rest. In addition the concentrations of ionized, pH-corrected ionized and total serum calcium were analyzed under bicycle exercise. Verapamil resulted in an increase of total serum calcium (p less than 0.02) and a fall in midregional parathyroid hormone concentrations (p less than 0.02) at rest. There was also found a statistically significant elevation of both ionized (p less than 0.05) and pH-corrected ionized (p less than 0.05) plasma calcium, and a slight increase in the total calcium under exercise (p less than 0.1). Before verapamil a significant negative correlation between total calcium and midregional parathyroid hormone was evident (r = -0.618; p less than 0.05), which however could not be clearly discerned after verapamil.

[The effect of verapamil on adrenocortical hormone secretion]

Variations in circadian cortisol rhythm, morning ACTH concentration and the 24-hour cortisol excretion were examined in 15 healthy volunteers and 9 untreated patients with cardiovascular diseases. These variations were measured under basal conditions and during low dose (ACTHL-test) and also a high dose (ACTHH-test) ACTH stimulation. Additionally, in the patients with cardiovascular diseases the effect of verapamil-administration was investigated. Under basal conditions no significant differences were to be seen between normal subjects and the patients, either before or after therapy. The two functional tests resulted in almost identical increases of cortisol and ACTH levels, both in healthy subjects and the patients before verapamil. It was found that after verapamil application during the ACTHL-test, the levels of plasma cortisol decreased in comparison with the values noted before verapamil (p less than 0.05). However, in the ACTHH-test a significant increase of the plasma cortisol (p less than 0.05) was evident. Our results lead to the conclusion that after verapamil therapy, under slight loading, the plasma cortisol concentration can be expected to decrease slightly, and in extremely high stress situations it will increase.