Sulfate sensitivity of aquatic organism in soft freshwaters explored by toxicity tests and species sensitivity distribution

Elevated concentrations of sulfate in waterways are observed due to various anthropogenic activities. Elevated levels of sulfate can have harmful effects on aquatic life in freshwaters: sulfate can cause osmotic stress or specific ion toxicity in aquatic organisms, especially in soft waters where Ca²⁺ and Mg²⁺ concentrations are low. Formerly, chronic toxicity test data in soft water have been scarce. The chronic and acute sulfate toxicity tests conducted with aquatic organisms from 10 families across various trophic levels in this study multiplied the number of tests conducted in soft freshwater conditions and enabled derivation of the species sensitivity distribution (SSD) and sulfate hazardous concentrations for soft freshwaters. The cladoceran Daphnia longispina and freshwater snail Lymnaea stagnalis were the most sensitive to sulfate among the studied species. Harmful effects on the reproduction of D. longispina were observed at 49 mg SO₄ /L while growth of L. stagnalis was inhibited at 217 mg SO₄ /L. Most studied organisms tolerated high sulfate concentrations: the median of chronic effective concentrations (EC10 or LC10) was 1008 mg/L for all the species tested in this study. Based on the species sensitivity distribution of the studied species the hazardous concentration for 5 % of aquatic organism (HC5) in soft waters was 117-194 mg SO₄/L. Different data set combinations were used to demonstrate the data variability in SSD-based HC5 estimates. The lowest values were produced from combining biotest results from the present study and earlier literature, while the highest values were calculated from the present study only. The derived chronic no-effect concentrations (PNEC) varied between 39 and 65 mg SO₄/L.

Review of data quality assessment frameworks experiences around Europe

In the first phase of its work, WP6 has explored and synthesized existing knowledge and experiences on data quality assurance frameworks (DQAFs) in the context of cross-border sharing of federated secondary use health data. Our aim was to identify good practices within this area and develop a first set of corresponding recommendations. The recommendations reflect the synthesis of results from three parallel lines of work, each utilizing a different methodology: a) thematic workshops and partner meetings, b) analysis of existing data-sharing initiatives, and c) a scoping literature review. Our analysis of literature and existing health data initiatives suggest that currently deployed DQAFs cannot as such serve as platforms or models for an EHDS-wide data quality solution. There is an agreement in principle, that reliability, relevance, timeliness, coherence, coverage and completeness should be incorporated in a DQAF as measurable dimensions of data quality. We aim towards a working definition of data quality, which will be able to reflect the reality of the data, as well as its fitness for purpose from the perspective of potential users.

• We recommend focusing efforts on transparency at the level of data holder institutions across Member States in relation to adoption of regular audits, a well-developed DQAF and clear procedures with regard to processing the data.

• In the medium to longer-term EHDS nodes could promote and support the development of a benchmarking process, which will assist data managers and data holder institutions with alignment against a Europe-wide approach to measuring data quality within and across Member States.

Review of interoperability standards as data quality supporting elements

WP6 has approached the target of supporting trustworthy secondary use of health and health care data through two operational objectives: developing the EHDS data quality assurance framework for real-world health data and developing the EHDS secondary use Semantic Interoperability Framework. For the latter objective, several interoperability standards were identified in accordance with the EHDS2 data life cycle and user's journey approach, hence focusing on data discoverability (at data source and variable levels), communication support across nodes and on development of common data models. Selection was based on active participation of WP6 leaders in various pertinent workshops and interactive activities, both in the framework of TEHDAS (Stakeholder and Project Forum meetings) as well as other relevant initiatives (e.g. the PHIRI project). Input was also sought from Commission representatives and EU-level regulatory authorities. In a first step, standards were catalogued based of features such as typology of interest, utility and application domains. In the next phase we organised virtual semi-structured interviews with key representatives of over 20 standards (incl. HL7, SNOMED, CDISC, DCAT, OMOP etc.). The focus of the interviews targeted experiences in standards’ actual use, challenges in their implementation, issues of maintenance and sustainability, as well as undergoing collaborations and developments. Sessions were recorded and subsequently the transcripts of discussion extracted automatically. The process of analysing interview materials is presently ongoing, using an adapted version of the Common Assessment Method for Standards and Specifications (CAMSS) v.4.0.0. toolkit. Interim results will be discussed within the Joint Action meeting activities in June 2022, to produce a version for wider stakeholder dialogue later in the fall. Results and recommendations generated through this process will also be presented for discussion with the workshop audience.

Sulfate toxicity to early life stages of European whitefish (Coregonus lavaretus) in soft freshwater

Sulfate occurs naturally in the aquatic environment but its elevated levels can be toxic to aquatic life in freshwater environments. We investigated the toxicity of sulfate in humic, soft freshwater to whitefish (Coregonus lavaretus) from fertilization of eggs to hatching i.e. during the critical phases of whitefish early development. Anadromous Kokemäenjoki whitefish eggs and sperm during fertilization, embryos and larvae were exposed in the long-term 175-day incubation to seven different sodium sulfate (Na₂SO₄) concentrations from 44 to 2 000 mg SO₄ L^-1. Endpoint variables were the fertilization success, offspring survival and larval growth. Egg fertilization and early embryonic development were the most sensitive developmental stages of whitefish to sulfate, although the fertilization success and survival of embryos decreased only in the highest concentration of 2 000 mg SO₄ L^-1. The survival during late embryonic period, hatching and the 5-day larval period was high and no difference between the control and sulfate treatments were observed. LC₅₀-values of sulfate for early embryonic period and for the entire embryonic and larval period was 1 413 and 1 161 mg L^-1, respectively. The NOEC (No-observed Effect Concentration) of sulfate for the both periods was 1 207 mg L^-1. The tolerance of whitefish early stages to sulfate toxicity seems to be on the same level as the tolerance of other salmonids' early stages.

Finnish and Swedish prehospital emergency care providers' knowledge and attitudes towards pressure ulcer prevention

BACKGROUND

Despite the knowledge that transportation by emergency medical services may increase the risk of pressure ulcers (PU), there is still lack of knowledge about the possibility of prehospital emergency care providers to be a part of preventing and reducing the risk of PUs.

METHODS

A survey was carried out during 2017 in Finland and Sweden. Validated questionnaires were used.

RESULTS

A total of 179 (72.7%) Finnish and 188 (28.8%) Swedish prehospital emergency care providers participated in the study. The overall rate of correct answers and the mean total knowledge score was 58.8% (SD 21.8), 20/34, in the Finnish group and 70.5% (SD 15.7), 24/34, in the Swedish group (p < 0.000). The percent of the total and the mean attitude score was in the Finnish group 71.3% (SD 0.48), 37.1/52, and in the Swedish group 69.4% (SD 0.77), 36.1/52 (p < 0.813). Half of the Finnish and most of the Swedish participants felt they needed more education about PUs (Fin 50.2% & Swe: 76.0%).

CONCLUSIONS

Prehospital emergency care providers don't see themselves as responsible for PU prevention. Therefore, there is a need for increasing the level of knowledge on PU prevention and classification among prehospital emergency care providers. They could play a key role in developing methods to improve PU prevention and identifying patients in risk of developing PUs.

Biodegradation of inorganic drug delivery systems in subcutaneous conditions

Despite extensive efforts to develop delivery systems for oral administration, subcutaneous (s.c.) injection remains the most common way to administer peptide drugs. To limit the number of frequent injections, sustained release systems that are easy to produce, suitable for various drugs, safe and biodegradable are urgently needed. Porous silicon (PSi) has been recognized to be one of the most promising materials for s.c. peptide delivery, but its biodegradation in s.c. tissue has not been studied in vivo, despite extensive in vitro research. In the present study, differently modified PSi microparticles were injected s.c. in mice, after which the morphology of the particles was thoroughly studied with transmission electron microscopy, micro-computed tomography and X-ray diffraction. Furthermore, histopathology of the s.c. tissue was analyzed to evaluate biocompatibility. To the best of our knowledge, this is the first systematic study which reveals the degradation behavior of various PSi materials in vivo. The PSi surface chemistry significantly affected the biodegradation rate of the s.c. injected microparticles. The most hydrophobic PSi microparticles with hydrocarbonized surface showed the lowest biodegradation rate while the hydrophilic microparticles, with oxide surface, degraded the fastest. The results from different empirical methods complemented each other to deduce the biodegradation mechanism of the inorganic delivery system, providing useful information for future development of s.c. carriers.

Fluorescent probes as a tool for cell population tracking in spontaneously active neural networks derived from human pluripotent stem cells

Applications such as 3D cultures and tissue modelling require cell tracking with non-invasive methods. In this work, the suitability of two fluorescent probes, CellTracker, CT, and long chain carbocyanine dye, DiD, was investigated for long-term culturing of labeled human pluripotent stem cell-derived neural cells. We found that these dyes did not affect the cell viability. However, proliferation was decreased in DiD labeled cell population. With both dyes the labeling was stable up to 4 weeks. CT and DiD labeled cells could be co-cultured and, importantly, these mixed populations had their normal ability to form spontaneous electrical network activity. In conclusion, human neural cells can be successfully labeled with these two fluorescent probes without significantly affecting the cell characteristics. These labeled cells could be utilized further in e.g. building controlled neuronal networks for neurotoxicity screening platforms, combining cells with biomaterials for 3D studies, and graft development.

Local staging of rectal cancer using the black lumen magnetic resonance imaging technique

BACKGROUND AND AIMS

The treatment of rectal cancer is comprised of surgery and possible adjuvant therapy depending on the stage of the tumour. This prospective study evaluates the accuracy of magnetic resonance imaging (MRI) in the preoperative staging of rectal cancer using an endorectal and intravenous contrast.

MATERIALS AND METHODS

37 consecutive patients with rectal cancer were imaged using a mixture of ferumoxsil and methylcellulose endorectally, and a gadolinium contrast intravenously. 33 tumours were resected and 4 tumours were considered unresectable during operation. The images were reviewed for local staging of the tumours. A tumour confined to the rectal wall was classified as a negative finding and a tumour invading through muscularis propria as a positive finding. The results were correlated with the histopathologic t stage (n = 33), or the clinical status (n = 4).

RESULTS AND CONCLUSIONS

of 37 cases, 20 (51 %) were true positive, and 11 (28%) were true negative. There were 3 false negative and 3 false positive cases. The sensitivity was 87%, specificity 79%, and diagnostic accuracy 84%. for the non-contrast images the figures were 78%, 79% and 78%, respectively. We consider black lumen magnetic resonance imaging to be a useful method for preoperative local staging of rectal cancer.

Assessment of CPR-D skills of nurses in Göteborg, Sweden and Espoo, Finland: Teaching leadership makes a difference

INTRODUCTION

Construction of an effective in-hospital resuscitation programme is challenging. To document and analyse resuscitation skills assessment must provide reliable data. Benchmarking with a hospital having documented excellent results of in-hospital resuscitation is beneficial. The purpose of this study was to assess the resuscitation skills to facilitate construction of an educational programme.

MATERIALS AND METHODS

Nurses working in a university hospital Jorvi, Espoo (n=110), Finland and Sahlgrenska University Hospital, Göteborg (n=40), Sweden were compared. The nurses were trained in the same way in both hospitals except for the defining and teaching of leadership applied in Sahlgrenska. Jorvi nurses are not trained to be, nor do they act as, leaders in a resuscitation situation. Their cardiopulmonary resuscitation (CPR) skills using an automated external defibrillator (AED) were assessed using Objective Structured Clinical Examination (OSCE) which was build up as a case of cardiac arrest with ventricular fibrillation (VF) as the initial rhythm. The subjects were tested in pairs, each pair alone. Group-working skills were registered.

RESULTS

All Sahlgrenska nurses, but only 49% of Jorvi nurses, were able to defibrillate. Seventy percent of the nurses working in the Sahlgrenska hospital (mean score 35/49) and 27% of the nurses in Jorvi (mean score 26/49) would have passed the OSCE test. Statistically significant differences were found in activating the alarm (P<0.001), activating the AED without delay (P<0.01), setting the lower defibrillation electrode correctly (P<0.001) and using the correct resuscitation technique (P<0.05). The group-working skills of Sahlgrenska nurses were also significantly better than those of Jorvi nurses.

CONCLUSIONS

Assessment of CPR-D skills gave valuable information for further education in both hospitals. Defining and teaching leadership seems to improve resuscitation performance.

Teaching basic life support to nurses

BACKGROUND AND OBJECTIVE

Every member of healthcare personnel should be able to perform basic life support including defibrillation (CPR-D). The biggest cost of implementation is training and these costs need to be reduced. The purpose of this randomized study was to evaluate the applicability of distance learning as a method to teach CPR-D.

METHODS

Nurses (n = 56) working in a geriatric hospital were randomized into three groups. The first group was given the Internet-based CPR-D course and the second was given a traditional, small-group CPR-D course. A third group without specific training in CPR-D served as a control group. An objective structured clinical examination (OSCE) was performed 2 weeks after the courses with a manikin patient having a cardiac arrest.

RESULTS

The median score of all participants was 31/49 (range 21-38). The reliability of the checklist was adequate (Cronbach alpha 0.77). Nurses receiving traditional CPR-D performed better than those receiving the Internet-based course (median score 34 vs. 28, P < 0.05) and the control group (median score 34 vs. 26, P < 0.0001). Nurses receiving Internet-based course performed similarly as the control group (median score 28 vs. 26, ns).

CONCLUSIONS

Distance learning cannot substitute for traditional small-group learning.

An electrospray ionization Fourier transform ion cyclotron resonance mass spectrometric study of the gas-phase stabilities and fragmentation of N-alkylammonium resorcarenes

Five N-alkylated ammonium resorcarene derivatives, differing either in the nitrogen atom or in the lower rim alkyl chain, were studied using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The main purpose was to clarify the fragmentation and the relative stabilities of the protonated molecules by collision-induced dissociation (CID) experiments. The results indicate that fragmentation of the upper rim alkyl amino substituents at the 2-position occurs readily. Variation in the gas-phase stabilities of these molecules was also observed. In addition, the proposed fragmentation pathways are depicted.

Patterns of Dermal Exposure to Hazardous Substances in European Union Workplaces

Workplace dermal exposure assessment is a complex task that aims to understand the dynamic interaction between the skin and the hazardous substances present in the surrounding environment. A European project known as RISKOFDERM gathered dermal exposure data in 85 workplaces (industrial and other types) in five countries in Europe. In order to optimize data collection and to develop a representative picture of dermal exposure, scenarios (tasks made up of a series of activities) were grouped together into dermal exposure operation units (DEOs). The allocation of scenarios to relevant DEOs was achieved on the basis of similarities of exposure routes, tasks and professional judgement. Sampling and quantification procedures were based on the approaches recommended by the OECD protocol. The laboratories involved in the analysis of the samples participated in quality assurance programmes. This exercise resulted in 419 body measurements and 437 measurements on hands expressed in terms of formulation (product) in use. Exposures for a given scenario varied by several orders of magnitude. The extent and patterns of exposure were found to be dependent on various exposure determinants, including inter- and intra-scenario variations. Hands were found to be the most contaminated parts of the body. Exposure patterns for liquid and solid contaminants were different. On the basis of the analysis of the data presented here, the averaged results (median and 95th percentile) for a given DEO unit should not be used as a representative measure of dermal exposure for all scenarios within that DEO without taking the exposure determinants into account. However, the data could be used to develop an exposure matrix (indicative exposure distributions) for different types of scenario and workplace, using determinants of exposure and a Bayesian approach to integrating expert opinion.

Expression of cyclooxygenase-2 in intestinal goblet cells of pre-diabetic NOD mice

Cyclooxygenase, the rate-limiting enzyme in prostaglandin synthesis, is expressed in constitutive (COX-1) and inducible (COX-2) isoforms. The COX-2 has been proposed to be involved in development of autoimmune type 1 diabetes (T1D). We examined COX-2 expression in the gut-associated lymphoid tissue (GALT), and found COX-2 was strongly expressed in goblet cells of non-obese diabetic (NOD) mice at the apical villi at the age of 2.5 weeks, clearly before the onset of insulitis, while the expression in the control BALB/c mice was weak or absent at all ages (P < 0.001). Lipopolysaccharide (LPS) given intraperitoneally slightly increased COX-2 expression in the goblet cells and epithelium of both NOD and BALB/c mice. High-resolution confocal microscopy showed that the surroundings of the goblet cells contained no COX-2, implying that the enzyme is synthesized by the goblet cells. The COX-2 is secreted from goblet cells into the intestinal lumen along with mucins. The COX-2 concentration in the goblet cell of BALB/c and especially of NOD mice was markedly higher than that in the intraepithelial lymphocytes or lamina propria macrophages. High mucin COX-2 from goblet cells may increase luminal prostaglandin synthesis, alter epithelial permeability, modulate intestinal immune responses and modify functional properties of the lymphocytes in the GALT, which all may be important for the initiation of the autoimmune phenomenon in the NOD mice.

Applicability of homogeneous exposure groups for exposure assessment in the chemical industry

The purpose of the study was to assess occupational exposure to chemicals, by taking the aspects presented in European standard EN 689 into account, especially with respect to homogeneous exposure groups and their suitability as the basis for exposure assessment. In addition, dermal exposure to chemicals was assessed when appropriate. The industries studied included a plywood factory, a paint factory and a sewage treatment plant of an oil refinery. The workers were classified into homogeneous exposure groups by the persons in charge of occupational health issues in the respective workplaces. The concentrations of the contaminants were measured in workplace air by breathing-zone and stationary sampling, and these approaches were compared. Dermal exposure was measured when applicable. The homogeneity of the grouping was tested with analysis of variance whenever possible. The tasks studied in plywood manufacturing fulfilled the criteria of homogeneous exposure groups for both respiratory and dermal exposure. The group of operators in the sewage treatment plant was highly homogeneous. The complicated organization of the tasks made the use of homogeneous exposure groups (HEG) unsuitable at the paint factory. These findings show that reliable exposure assessment cannot be achieved with a formal standard; instead, comprehensive occupational hygiene evaluation is needed. It should also have a great importance when exposure models are developed.

Expression of insulin-receptor substrate-1 and -2 in ovaries from women with insulin resistance and from controls

OBJECTIVE

To evaluate the role of insulin-receptor substrate (IRS)-1 and -2 in ovary dysfunction in women with insulin resistance.

DESIGN

Immunoblotting and immunohistochemical analyses of the localization and staining intensity of IRS-1 and IRS-2 in the ovaries of women with the polycystic ovary syndrome (PCOS) and gestational diabetes mellitus.

SETTING

Department of Obstetrics and Gynecology, Turku University Central Hospital.

PATIENT(S)

Sections of ovary were obtained at the time of cesarean section from five volunteers without medical complications and three patients with gestational diabetes mellitus. Paraffin-embedded ovary sections were selected from those on file from the department of pathology; four were from women with a histologic diagnosis of PCOS and seven were from women with endometriosis (controls).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Protein expression of IRS in human ovary samples.

RESULT(S)

Immunoblotting with specific monoclonal and polyclonal antibodies showed the presence of 165-kDa and 183-kDa proteins that corresponded to the size of IRS-1 and IRS-2, respectively, in normal pregnant ovaries and human cultured follicles. Immunohistochemical staining showed that positive IRS-2 expression in antral follicles was restricted to theca internal cells in ovulatory ovaries but was distributed widely in all compartments of follicles in different stages in polycystic ovaries. Compared with follicles at a similar stage of development in ovulatory ovaries, follicles in polycystic ovaries showed decreased staining for IRS-1 in granulosa cells but increased staining for IRS-2 in theca internal cells. These features of IRS-1 and -2 expression were also noted in preantral and atretic follicles from patients with gestational diabetes mellitus compared with those who had uncomplicated pregnancy.

CONCLUSION(S)

This study highlights a shift of the follicular insulin signal protein from IRS-1 to IRS-2 in insulin-resistant states and suggests an association between this change and ovarian abnormality in PCOS and gestational diabetes mellitus.

New world, but not Old World, monkeys carry several genes encoding beta-microseminoprotein

It was shown by Southern hybridization that cotton-top tamarin and common marmoset, New World monkeys, carry three or more genes encoding beta-microseminoprotein, also known as PSP94. In contrast, the genomes of Old World monkeys, as represented by rhesus macaque and sacred baboon, contain a single gene. Clones containing three different genes encoding beta-microseminoprotein were isolated from a cotton-top tamarin genomic library. They carry two complete genes of four exons and a third gene lacking the first exon. The structure suggests that the three genes are functionally active and give rise to transcripts that are approximately 86% similar in sequence. By sequencing one gene in full, it was shown that the introns carry an excess of interspersed repeats, on average 29% of the introns consist of Alu repeats. A phylogenetic analysis demonstrated that the genes probably arose in New World monkeys after the separation from Old World primates.

Assessment of total exposure to phenol-formaldehyde resin glue in plywood manufacturing

OBJECTIVE

Respiratory and dermal exposure to phenol-formaldehyde resin-glue components used in plywood manufacturing were assessed.

METHODS

Formaldehyde and phenol were monitored in the workplace air. Formaldehyde was measured both in the breathing zones of the workers and at stationary sampling sites. Phenol was used as a marker agent for dermal exposure due to its near-nonvolatility at the temperatures occurring during the present study and to its ready absorption through the skin, causing systemic exposure in addition to local skin rashes. Sampling and analytical methods were developed to measure the dermal exposure to phenol. Sampling was accomplished with whole-body dosimetry using Tyvek coveralls and cotton gloves. In addition, a liquid chromatography method was developed for the analysis of phenol from dermal exposure samples.

RESULTS

As expected, formaldehyde was noted to be the major compound causing respiratory exposure. When exposure assessment was done on the basis of air samples collected both at stationary sampling sites and in the breathing zones of the workers the agreement between the results obtained was good. The dermal sampling revealed that the workers were exposed to phenol, but the risk for toxic effects was slight due to the low concentrations of urinary phenol.

CONCLUSIONS

We conclude that it is possible to use the stationary sampling method for the assessment of respiratory exposure in a plywood factory instead of the usually more complicated breathing-zone sampling. This study also demonstrates the importance of taking dermal exposure into account, at least due to the ability of the resins to cause skin rashes, in assessment of the exposure to chemicals in plywood manufacturing.

Separation of linoleic acid oxidation products by micellar electrokinetic capillary chromatography and nonaqueous capillary electrophoresis

In this work the suitability of micellar electrokinetic capillary chromatography (MEKC) and nonaqueous capillary electrophoresis (CE) to the analysis of the primary oxidation products of linoleic acid was studied with uncoated fused-silica capillaries. The primary autoxidation products of linoleic acid are the four hydroperoxide isomers 13-hydroperoxy-cis-9, trans-11-octadecadienoic acid, 13-hydroperoxy-trans-9, trans-11-octadecadienoic acid, 9-hydroperoxy-trans-10,cis-12-octadecadienoic acid, 9-hydroperoxy-trans-10, trans-12-octadecadienoic acid. Addition of a surfactant such as sodium dodecyl sulfate (SDS) or sodium cholate (SC) into the running buffer (20-30 mM 3-(cyclohexylamino)-1-propanesulfonic acid (CAPS) or ammonium acetate, pH 9.5-11) was required to enhance the water solubility of the sample and selectivity of the separation. MEKC proved to be a promising new technique for the separation of the primary oxidation products of lipids giving results comparable to high performance liquid chromatography (HPLC). Partial separation of hydroperoxide isomers was also achieved using nonaqueous CE with methanol-acetonitrile-sodium cholate as running buffer.

Coronary pressure as a determinant of B-type natriuretic peptide gene expression in isolated perfused adult rat heart

The role of coronary flow in the regulation of ventricular B-type natriuretic peptide (BNP) gene expression was studied in isolated perfused rat heart preparation. The increase of coronary flow from 5 ml/min to 20 ml/min for 2 h resulted in a 132+/-6 mm Hg increase in aortic perfusion pressure. The changes in BNP mRNA and immunoreactive BNP (IR-BNP) levels in response to hemodynamic stress were compared to those of c-fos and adrenomedullin (ADM) gene expression. The increase of coronary flow resulted in 1.5-fold increases in the left ventricular BNP mRNA (P < 0.001) and IR-BNP (P < 0.05) levels in 2-month old rats. There was also a 1.5-fold (P < 0.05) increase in ventricular c-fos mRNA levels, whereas ADM mRNA levels decreased by 74% (P < 0.001) in the left ventricle. In 18-month old rats, the increase in coronary flow decreased left and right ventricular BNP mRNA levels by 18% (P < 0.05) and 39% (P < 0.001), respectively. There were no changes in IR-BNP peptide and c-fos mRNA levels, whereas ADM mRNA levels decreased by 46% (P < 0.001) in the left ventricles. The results show that increased aortic perfusion pressure results in differential expression of cardiac genes including up-regulation of ventricular BNP and c-fos gene expression and down-regulation of ADM gene expression. Furthermore, aging seems to elevate the threshold at which hemodynamic stress of the heart results in a response at BNP gene level.

p53 expression in skin carcinogenesis and its relationship to cell proliferation and tumour growth

The immunoreactivity of p53 protein was studied in relation to tumour development, histopathological characteristics, cell proliferation, and basement membrane organisation following the induction of skin carcinogenesis in tumour-sensitive and -resistant mouse strains by ultraviolet (UV) irradiation or 7,12-dimethylbenz(a)anthracene (DMBA). In non-neoplastic skin exposed to UV irradiation or DMBA, p53 immunoreactivity was observed in nearly 50% of the basal layer cells. These cells were morphologically and histochemically indistinguishable from the p53-negative cells, occurring similarly in the tumour-producing and the tumour-negative mouse strains and regardless of subsequent tumour formation. In induced epidermal hyperplasia and in benign tumours, p53-positive and proliferating cells constituted 40-50% of all cells in the basal layer, while superficial cells were p53 negative. In dysplastic epidermis, p53-positive cells and proliferating cells were seen in all cell layers. In the case of squamous cell carcinomas, p53-positive proliferating cells in differentiated neoplasms were localised close to the basement membrane and, more frequently, in border areas showing invasion and basement membrane destruction. In horn cysts, centrally located cells were non-proliferating and p53 negative. In moderately differentiated neoplasms, proliferating cells were located closer to the basement membrane, while p53-positive cells were distributed diffusely in the neoplasm. In poorly differentiated neoplasms, p53-positive cells were more common than proliferating cells and were arranged in a diffuse pattern. The results showed that the number and location of p53-positive cells depended upon histology, with a close relationship to tumour type and degree of malignancy, but not on the mode of induction, nor on the animal strain or the relationship to subsequent tumour formation.

Skin tumor development and keratin expression in different experimental models. Relation to inducing agent and target tissue structure

The applicability of the experimental skin carcinogenesis model for studies of tumor development was examined by exposing the skin of various mouse strains to different chemical carcinogens and UV radiation regimens, in order to analyze the development and progression of the neoplastic process and the role of differentiation markers such as keratins. In tumor-sensitive hairy NMRI mouse skin, the chemical carcinogen, 7,12-dimethylbenz(a)-anthracene (DMBA) induced an abnormal epidermal cell differentiation and structural irregularities associated with an altered keratin expression, as well as numerous papillomas and squamous cell carcinomas. A suboptimal dose of UVB irradiation increased the number of DMBA-induced benign squamous neoplasms. Low doses of benzo(a)pyrene resulted in mild epidermal alterations, but only in one tumor. High doses of UVB induced a large number of undifferentiated spindle cell tumors with few keratinpositive cells in NMRI mice, similar though fewer tumors in hairy, heavily pigmented C57BL/6 mice, numerous papillomas and squamous cell carcinomas in hairless hr/hr mice but only two papillomas in hairy, moderately pigmented DBA/2 mice while UVA exposure produced only two papillomas in hairless SKH-1 mice. In conclusion, the extent and type of skin tumor development depended upon the induction regimen: physical, chemical, dose and duration, as well as on the skin structure: pigmentation and adnexal development, all of which have to be taken into account when relating experimental results to human conditions.

Collagenous colitis and Yersinia enterocolitica infection

Collagenous colitis is a rare clinical and pathological entity characterized by watery diarrhea and deposition of collagen beneath the surface epithelium of the colon. Its etiology is unknown. We present a careful retrospective clinicopathological analysis of six patients with collagenous colitis diagnosed at our hospital during a three-year period. Three of the patients had had a Yersinia enterocolitica infection, detected by stool culture and elevated serum antibody titers, preceding the diagnosis of collagenous colitis. Four patients had duodenal villous atrophy, which in two patients was refractory to a gluten-free diet. We propose that Yersinia enterocolitica infection may be a triggering factor for the development of collagenous colitis in some cases. Duodenal villous atrophy not responding to gluten withdrawal is common in association with collagenous colitis.

Epidermal cell adhesion and basement membrane alterations in experimental skin tumour development

BACKGROUND

Epidermal cell adhesion and basement membrane (BM) are essential for the differentiated structure of squamous epithelium, and both are reduced in malignant tumours.

MATERIALS AND METHODS

We analysed the expression of cell adhesion-related proteins desmoplakin and E-cadherin, BM components laminin and collagen IV, and BM receptor integrin alpha 6 in experimental preneoplastic changes and neoplasms of skin. Different mouse strains (NMRI, C57Bl/6 and DBA/2) and exposure protocols (DMBA, UV, DMBA + UV) were used to find possible differences in the expression of cell adhesion and BM proteins within individual tumour types.

RESULTS

The individual strain had an impressive role on the expression of tumors. The exposure model affected the type of tumour found and tumour behaviour. The location and expression of cell attachment proteins were dependent on morphology, but mouse strain and type of exposure had no effect. The decline in the expression of markers studied was gradual involving the cytoplasmic immunoreactivity of integrin alpha 6 and laminin observed in dysplastic epidermis, BM structure formation becoming increasingly disturbed in dysplasia; this was present in squamous cell carcinomas and absent in undifferentiated tumours. Desmoplakin expression gradually disappeared during the decline in differentiation. E-cadherin expression was preserved longer, and disappeared along with the loss of squamous properties.

CONCLUSIONS

Desmoplakin and E-cadherin served in this study as differentiation markers. None of these proteins seem to explain the differences in the tumour sensitivity of individual mouse strains.

Conserved region mutations of the p53 gene are concentrated in distal colorectal cancers

Distal colorectal cancers, especially those in the rectum, are more aggressive and more commonly recurrent than proximal cancers. We studied the possible relationship between p53-gene mutation type and location of the tumour, since mutations in the conserved areas of the p53 gene have been suggested to result in a poorer outcome of colorectal cancer than mutations outside these areas. Exons 5 to 8 of the p53 gene were studied in specimens from 72 colorectal-cancer patients. Polymerase-chain-reaction-amplified products of tumour DNA were analyzed by automated direct sequencing. Of the mutations detected in distal cancers, 71% were located in conserved regions of the gene, while only 42% of the mutations in proximal cancers were in these areas. In rectal cancers, 81% of the mutations were located in conserved regions. The tumours with mutations in the conserved regions were more often poorly differentiated (23%) than those with other mutations (0%). Our results indicate that mutations in the conserved regions of the p53 gene accumulate in distal but not in proximal tumours. This difference may be related to the more aggressive behaviour and to different aetiological factors associated with distal tumours.

Quinolone antibacterials: a new class of photochemical carcinogens

Hairless mice were exposed orally to antibiotics of the fluoroquinolone group alone and in combination with irradiation with UVA over an extended period of time to determine the possible skin carcinogenicity in comparison with that with 8-methoxypsoralen, i.e. a known photochemical skin carcinogen. Animals exposed to UVA and fleroxacin, ciprofloxacin, nalidixic acid and ofloxacin exhibited an increase in the number of benign skin tumors when compared with animals exposed to UVA alone. Animals exposed to lomefloxacin and UVA exhibited a specific type of neoplastic progression. In addition to benign papillomas and solar keratoses, a number of cystic squamous cell carcinomas were observed. In the positive control group, which was given 8-methoxypsoralen and UVA, a number of papillomas and superficial squamous cell carcinomas were found. In animals exposed to UVA alone, only a few benign tumors were seen; in unexposed animals, no cutaneous neoplasms were observed. It is concluded that fluoroquinolones warrant further study, because they have potential photocarcinogenic properties.

Oncogenes and growth factors as indicators of carcinogen exposure

The occurrence of different components of the cell growth regulation pathway as expressed in experimental skin carcinogenesis in haired carcinogen-sensitive NMRI, in haired carcinogen resistant DBA/2 mice and in hairless SKH/1 mice was studied by morphological and immunohistochemical methods. The results were compared with respect to neoplastic response, number of tumors, tumor behaviour and to the inducing agent (UV irradiation or chemical carcinogen), in order to increase our understanding of specific alterations in neoplastic development caused by extraneous agents and to determine their possible usefulness as indicators of carcinogen exposure. The expression of growth factors (transforming growth factor alpha and epidermal growth factor), growth factor receptors (epidermal growth factor receptor/c-erbB-1 and c-erbB-2/neu), cell signalling component c-myc, the nuclear transcription factor Harvey-Ras and the tumor suppressor gene p53, were studied in carcinogen- and UV-induced tumor formation in mouse. The results showed increased oncogene expression as well as growth factor expression in the skin during tumor development appearing early in neoplastic and premalignant conditions and becoming more distinct during neoplastic progression. Efforts to delineate specifically initiated cells prior to the appearance of morphologically detectable alterations including dysplasia, papilloma formation and squamous cell carcinomas, were unsuccessful. Increased staining by antibodies to growth factors and oncogenes were also observed in DBA/2 animals resistant to tumor formation. It is concluded that oncogene expression and growth factor protein deposits are associated with carcinogenic effects, partly explaining the mechanism of action of these agents, but the applicability, as such, for the analysis of potential hazardous agents needs further studies.

Immunohistochemical study of type I collagen and type I pN-collagen in benign and malignant ovarian neoplasms

BACKGROUND

Type I collagen is a major constituent of the interstitial connective tissue. Although ovarian carcinoma is known to induce the expression of type I collagen in the peritoneal cavity, the distribution and metabolic activity of this collagen in ovarian tumor tissue are not known.

METHODS

The distributions and staining intensities of different molecular forms of type I collagen in ovarian neoplasms were studied immunohistochemically with antibodies to the aminoterminal propeptide of type I procollagen (PINP) and the cross-linked carboxyterminal telopeptide of type I collagen (ICTP), reflecting the presence of newly synthesized and old, cross-linked type I collagen, respectively.

RESULTS

A regular pattern of moderately staining, relatively uniform fibers was observed in the stroma of benign serous and mucinous cystadenomas, indicating limited participation in tumor growth. The staining was accentuated subepithelially in borderline epithelial neoplasms and in well differentiated cystadenocarcinomas, suggesting induction of the stromal collagen synthesis by the tumor cells. Fewer degraded collagen fibers were found in moderately differentiated carcinomas, most likely because of enzymatic degradation of the stroma surrounding the neoplasms during tumor spread. Strongly staining, irregular collagen fibers occurred closely around islets of tumor cells in undifferentiated malignant neoplasms and in metastases of ovarian carcinomas; also, intracellular staining was present in part of the malignant cells. In most cases, the staining reactions obtained with the two different antibodies were similar, probably indicating rapid processing of the newly synthesized type I collagen (indicated by PINP) to a maturely cross-linked form (indicated by ICTP).

CONCLUSIONS

Synthetic and degradative processes are typical of the collagenous matrix in malignant ovarian tumors. Aberrant expression of type I collagen may occur in anaplastic ovarian carcinomas.

Benzo[a]pyrene-7,8-diol-9,10-epoxide-DNA adducts and increased p53 protein in mouse skin

p53 protein expression has been shown to increase in response to DNA damage in cell culture systems. We have studied p53 expression and benzo[a]pyrene (B[a]P)-induced DNA-damage in the form of benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE)-DNA adducts as measured by synchronous fluorescence spectrophotometry (SFS) in B[a]P-treated C57BL/6 mouse skin. Polyclonal murine antibody CM5, which is comparable to human CM1, detecting both wild-type and mutated protein, was used. BPDE-DNA adducts reached their maximum at 24 h after all dosage regimens, but were very well detectable also at 12 and 48 h after the treatment, while no adducts were measurable at 1 week and thereafter. p53 expression was seen in 9/17 (53%) skin samples from mouse treated with 500 microgram of B[a]P 12-48 h after the treatment, while all 25 (100%) cases of similarly treated mouse skins were negative after 30 weeks of the treatment. Only one positive sample of total 11 was found among mice treated with repeated 62.5 micrograms doses and this was 24 h after the last treatment. After one 62.5 micrograms dose all mice were negative. This is the first report of an association of p53 protein with DNA damage in vivo and gives support for the putative function of p53 in cellular defense machinery towards chemical damage.

Effects of intraventricular taurine, homotaurine and GABA on serum prolactin and thyrotropin levels in female and in male rats

Serum prolactin and thyrotropin levels of conscious, unrestrained male and female rats were compared after intracerebroventricular (i.c.v.) administration of taurine, gamma-aminobutyric acid (GABA) and homotaurine. The amino acids studied had no clear effect on serum basal thyrotropin levels in male or female rats. All amino acids elevated serum prolactin levels in female rats at the dose of 5 mumol/rat; homotaurine by about 18-fold, taurine and GABA by 3-fold. Only homotaurine elevated serum prolactin of male rats at this dose, but its effect was less pronounced (p < 0.01) in male than in female rats. Although homotaurine was clearly more potent than the two other amino acids, at the dose of 10 mumol/rat taurine and GABA also elevated serum prolactin in male rats. These findings show that there are gender-related differences in the responses of serum prolactin levels to homotaurine, taurine and GABA in rats. The tuberoinfundibular dopaminergic pathway, which exerts tonic inhibitory influence on prolactin secretion, is sexually differentiated. Hence the gender-related differences in the effects of the amino acids on prolactin secretion suggest that they might inhibit dopamine release from the median eminence. In case of homotaurine, the gender effect was most pronounced. The less clear dependence of GABA's effect on the gender is in accordance with the suggestions that GABA influences the secretion of serum prolactin by more than one mechanism.

Effects of taurine, homotaurine and GABA on hypothalamic and striatal dopamine metabolism

To elucidate the effects of taurine on hypothalamic and striatal dopaminergic neurotransmission we compared its effects to those of gamma-aminobutyric acid (GABA) and homotaurine (a GABAA-receptor agonist) on hypothalamic and striatal concentrations of dopamine (DA) and its metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and, in the case of striatum, 3-methoxytyramine (3-MT) in rats. In addition, hypothalamic and striatal 5-hydroxytryptamine (5-HT) und 5-hydroxyindoleacetic acid, hypothalamic noradrenaline (NA) and 3-methoxy-4-hydroxyphenylglycol sulfate, and pituitary DA concentrations were also measured. The amino acids were injected into the lateral brain ventricles of conscious male rats in doses of 10 and 36 mumol/rat, and rat were sacrificed 15 and 60 min later, respectively. Homotaurine (by 11%) but not the other two amino acids elevated striatal DA, whereas hypothalamic DA was increased by both taurine (36%) and homotaurine (31%). All three amino acids at 36 mumol elevated striatal DOPAC, homotaurine (51%) more than taurine (31%) or GABA (30%), and hypothalamic DOPAC, both taurine (102%) and homotaurine (82%) clearly more than GABA (34%). Neither striatal nor hypothalamic HVA was altered by any of the amino acids. At 10 mumol the amino acids decreased striatal 3-MT by about 40%. At 36 mumol taurine and homotaurine reduced 3-MT by about 70%, whereas increasing the dose of GABA did not further reduce 3-MT. Both taurine and homotaurine at 36 mumol decreased hypothalamic NA content. Neither hypothalamic nor striatal 5-HT metabolism was altered. In the neurointermediate lobe of the pituitary gland taurine at 10 mumol but not at 36 mumol slightly (20%) increased DA.(ABSTRACT TRUNCATED AT 250 WORDS)

A microtiter plate assay for N-acetyl-beta-D-glucosaminidase using a fluorogenic substrate

We describe a simple endpoint method for the determination of N-acetyl-beta-D-glucosaminidase (NAGase; EC 3.2.1.30). NAGase uses a fluorogenic substrate, 4-methylumbelliferyl-N-acetyl-beta-D-glucosaminide, at pH 4.6, liberating the fluorescent 4-methylumbelliferone. The method is reproducible and fast both at room temperature and at 37 degrees C. The procedure developed can be used, e.g., in the diagnosis of bovine subclinical mastitis, where elevated NAGase activities are found in raw milk samples. The assay procedure has a high capacity and high sensitivity and several hundred milk samples can be screened per hour using 96-well microtiter plates and an automated fluorescence reader. In addition to its use in mastitis diagnosis, the assay can be used in the diagnosis of some diseases of human origin.