Toxicity of green tea extracts and their constituents in rat hepatocytes in primary culture

Recent reports on sporadic cases of liver disorders (acute hepatitis, icterus, hepatocellular necrosis) after ingestion of dietary supplements based on hydro-alcoholic extracts from green tea leaves led to restrictions of the marketing of such products in certain countries of the EU. Since green tea is considered to exert a number of beneficial health effects, and, therefore, green tea products are widely used as dietary supplements, we were interested in the possible mechanism of hepatotoxicity of green tea extracts and in the components involved in such effects. Seven hours after seeding on collagen, rat hepatocytes in primary culture were treated with various hydro-alcoholic green tea extracts (two different native 80% ethanolic dry extracts and an 80% ethanolic dry extract cleared from lipophilic compounds). Cells were washed, and reduction of resazurin, used as a viability parameter monitoring intact mitochondrial function, was determined. It was found that all seven green tea extracts examined enhanced resazurin reduction significantly at a concentration range of 100-500 microg/ml medium, while a significant decrease was observed at 1-3mg/ml medium. Decreased levels were concomitant with abundant necrosis as observed by microscopic inspection of the cultures and with increased leakage of lactate dehydrogenase activity from the cells. In a separate series of experiments, the green tea constituents (-)-epicatechin, (-)-epigallocatechin-3-gallate, caffeine and theanine were tested at concentrations reflecting their levels in a typical green tea extract. Synthetic (+)-epigallocatechin (200 microM) was used for comparison. Cytotoxicity was found with (-)-epigallocatechin-3-gallate only. The concomitant addition of 0.25 mM ascorbate/0.05 mM alpha-tocopherol had no influence on cytotoxicity. In conclusion, our results suggest that high concentrations of green tea extract can exert acute toxicity in rat liver cells. (-)-Epigallocatechin-3-gallate seems to be a key constituent responsible for this effect. The relatively low bioavailability of catechins reported after oral exposure to green tea argues, however, against a causal role of these constituents in the reported liver disorders.

Glucocorticoid receptor blockade disinhibits pituitary-adrenal activity during the stress hyporesponsive period of the mouse

During postnatal development, mice undergo a period of reduced responsiveness of the pituitary-adrenal axis, the stress hyporesponsive period (SHRP), which is largely under control of maternal signals. The present study was designed to test the hypothesis that this quiescence in hypothalamic-pituitary-adrenal (HPA) activity is mediated by glucocorticoid feedback. For this purpose, the role of mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) in control of HPA activity was examined during the SHRP and in response to 24 h of maternal deprivation. Nondeprived or deprived (24 h) CD1 mice on postnatal d 8 were injected sc at 16 and 8 h before testing with the MR antagonist RU28318 or the GR antagonist RU38486. The results showed that, in nondeprived mice, blockade of GR rather than MR triggered a profound increase in anterior pituitary proopiomelanocortin mRNA, circulating ACTH, and corticosterone concentrations. In contrast, CRH mRNA in hypothalamus and GR mRNA in hippocampus and hypothalamus were decreased. Blockade of the GR during the deprivation period amplified the rise in corticosterone induced by maternal deprivation, whereas it reversed the deprivation effect on the other HPA markers, leading to profound increases in plasma ACTH, proopiomelanocortin mRNA expression in the anterior pituitary, CRH mRNA expression in the paraventricular nucleus, and MR mRNA expression in the hippocampus, but not in GR mRNA expression in the hippocampus and paraventricular nucleus. In conclusion, the data suggest that control of postnatal pituitary-adrenal activity during the SHRP involves GR-mediated feedback in the anterior pituitary, which is further potentiated in the absence of the mother.

[Established nuclear medicine techniques for tumour diagnosis (tumour SPECT): can they still compete with (18)F-FDG-PET?]

This overview presents the indications of tumour SPECT in contrast to tumour PET using (18)F-FDG. A number of diagnostic SPECT radiopharmaceuticals have been used for years in oncology and are widely available in nuclear medicine departments. Today, tumour SPECT has to compete with tumour PET using (18)F-FDG. Other PET radiopharmaceuticals are common only in specialised centers. In comparison to SPECT, PET images with their higher resolution are technically superior. Therefore, PET is better than SPECT in localising a tumour, if the special tumour entity accumulates (18)F-FDG. Thus, (18)F-FDG-PET has largely replaced SPECT examinations using (201)Tl chloride, (67)Ga citrate or (99m)Tc anti-CEA. It is questionable whether mammascintigraphy using (99m)Tc-MIBI or (99m)Tctetrofosmine will be broadly accepted in clinical routine. SPECT radiopharmaceuticals are still up to date for examination of tumour entities which do not accumulate (18)F-FDG (e. g. neuroendocrine tumours) and in clinical problem solving if (18)F-FDG-PET is not regarded as superior (e. g. search for recurrent medullary thyroid carcinoma) or in the management of tumours with overlapping diagnosis and therapy as it is the case for differentiated thyroid carcinomas ((123)I/(131)I-NaI), phaeochromozytomas, and neuroblastomas ((123)I/(131)I-MIBG), carcinoids, gastroenteropancreatic tumours, paragangliomas, and Merkel-cell tumours (somatostatin receptor scintigraphy). Future developments concerning new SPECT radiopharmaceuticals and image fusion such as SPECT/CT are expected.

149 INTRAUTERINE CULTURE OF IN VITRO PRODUCED BOVINE EMBRYOS AND RECOVERY OF THE EMBRYOS AT DAYS 12 - 14

For stem cell production and detailed morphological analysis 12–14-day-old bovine embryos are suitable. However, it has been proven to be difficult to extend the in vitro culture period beyond Days 8–9, and it was the aim of the present experiment to examine whether it might be possible to culture 6–7-day-old in vitro-produced (IVP) embryos for a period of 5–7 days in the uterine horns of heifers. The IVP embryos were produced by standard procedures. Briefly, IVM took place in DMEM medium supplemented with 5% serum, EGF, and eCG/hCG, and IVF was carried out in TALP medium under 5% CO2 in humidified air and at 38.5°C. IVC took place in SOFaaci supplemented with 10% serum under 5% CO2, 5% O2 and 90% N2 at 38.5°C .The embryos were cultured in vitro to Days 6–7 post insemination, when morulas and blastocysts of excellent quality were placed in HEPES-buffered TCM199 with 10% serum, loaded in numbers of 10–30 into 0.25 mL straws, and then transported to the place of transfer in a portable incubator at 38.5°C. The embryos were transferred nonsurgically to the mid or distal part of the uterine horns of 28 dairy heifers which were heat synchronized with injections of cloprostenol (Estrumat Vet, Schering-Plough, Farum, Denmark) to a cycle stage of embryo age +1 day. In 16 heifers, embryos were transferred into both sides and for the remaining ones only into the horn ipsilateral to the ovary bearing the corpus luteum. After 5–7 days, the heifers were flushed nonsurgically by standard method, using a flushing catheter of large caliber (Minitab® 18 G) and slow infusion and evacuation of the fluid. The differences in recovering rate among horns were identified by Fisher's Exact test. Data are given as LS means ± SEM values and statistical differences assigned at the P < 0.05 level. In 6 of the 28 heifers no embryos were obtained; in these 6 cases, the quality of the transferred embryos, the transfer procedure, the heifers, and the flushing procedures did not differ in any obvious way from those of the successful flushings, which numbered 22 (79%). The mean embryo recovery rate was 40 ± 3% with a variation from 7% to 93%. There was a minor but not statistically significant difference between the overall recovery rate of embryos from the ipsi- versus contralateral horn, respectively (44 ± 5% vs. 38 ± 6%). In only 4 of the 16 heifers where transfer occurred to both horns was the recovery rate higher in contralateral side, compared to 9 heifers where the highest recovery rate was seen in the ipsilateral side. The oldest elongated embryos were in one occasion damaged and in another tangled, making it difficult to isolate the individual embryo; apart from that, all of the embryos seemed of excellent quality making it possible to isolate the embryonic discs. It can be concluded that it is possible to culture in vitro produced Day 6–7 bovine blastocysts in the uterus of synchronized heifers and to achieve an acceptable recovery of Day 12–14 embryos.

181 Oct-4: A POTENTIAL MARKER FOR PLURIPOTENCY IN CATTLE

The POU (Pit-Oct-Unc) domain transcription factor Oct-4 is one of the most acknowledged markers for pluripotency in murine and primate embryonic cells. At the blastocyst stage, expression of Oct-4 has been shown to remain high in the inner cell mass (ICM) while being rapidly down regulated in the trophectoderm (TE). Furthermore, in these species, expression of Oct-4 is maintained in pluripotent derivatives of the ICM and in embryonic stem (ES) cells, but lost upon differentiation. In the bovine embryo, a marker with similar qualities has long been sought. The aim of this study was to investigate, using a commercially available antibody for immunohistochemistry (IHC), whether Oct-4 might serve this role. In vitro produced (IVP) embryos were transferred to synchronized recipients at Day 6 post insemination (p.i) and flushed at Day 12; in vivo-derived embryos were flushed at Day 14. Day 8 IVP embryos (n = 20) were fixed and processed for IHC in paraffin sections together with Day 12 (n = 18) and Day 14 (n = 3) embryos. From Day 8 IVP embryos, outgrowth colonies (OCs) were formed by intact blastocyst culture on mouse SNL feeder cells. OCs were photographed using a stereomicroscope on Days 12, 14, and 16 p.i., and were examined for Oct-4 expression by in situ IHC at Day 16 p.i. (n = 94). From isolated embryonic discs of Day 12 embryos, OCs were derived by similar culture and were either processed for IHC on paraffin sections at Days 16, 18, and 20 p.i. (n = 9) or used for establishment of ES-like cell lines. Of colonies formed, representative specimens from each of the initial 5 passages (n = 18) were examined for Oct-4 expression either in paraffin sections or in situ. In Day 8 embryos, Oct-4 expression was demonstrated in all nuclei of both ICM and TE cells except for presumptive apoptotic ones. Approximately one-fifth of the OCs presented a substantial amount of Oct-4 positive cells of putative ICM, but also of TE origin. Apparently, the formation of Oct-4 positive OCs was favored by initial attachment of the embryonic pole to the feeder cells. In Day 12 and 14 embryos, specific and exclusive Oct-4 staining of nuclei of the complete epiblast, but not the hypoblast and the TE, was revealed. All OCs derived from Day 12 embryonic discs showed specific staining for Oct-4 in nuclei of putative epiblast origin only. On subsequent culture of these isolated epiblast derivatives, loss of Oct-4 staining from colonies was observed by passage 3. This study has, for the first time, shown expression of Oct-4 to be limited to pluripotent cells of bovine Day 12 and 14 embryos. Compared with murine and primate embryos, down-regulation of Oct-4 expression in bovine TE cells appears to be delayed. Findings indicate that Oct-4 may be used as a marker for pluripotency in bovine ES-like cells, although TE derivatives may maintain Oct-4 expression when isolated from Day 8 embryos.

The incidentaloma of the thyroid

The incidentally detected thyroid nodule using sonography is described as incidentaloma; the most nodules have a diameter up to 1.5 cm. Sonography will detect thyroid nodules in more than 20% of the population in Germany. Epidemiological studies investigating the prevalence of malignancy in such incidentalomas are missing. The incidence of differentiated thyroid cancer is about 3 per 100,000 people and year. However, several monocentric studies have shown a prevalence of malignancy of up to 10% of the thyroid nodules in selected patients’ group. The histology did not found microcarcinomas only, but also small cancer with infiltration of the thyroid capsule, lymph node metastasis or multifocal spread. The studies were not designed for outcome measurement after early and incidental detection of small thyroid cancers. Hypoechogenity, ill defined borders, central hypervascularization or microcalcifications were used as combined criteria for risk stratification. The second method for risk stratification is scintigraphy and further tests are warranted for hypofunctioning nodule ≥1 cm. Additionally, the family history, patient’s age <20 years, former radiation of the neck, and measurement of calcitonin should be regarded. Without such a risk stratification selection for fine needle aspiration is impossible. Fine needle aspiration of non-palpable incidentalomas led to non-representative or unequivocal cytological findings in up to 40%. Because better outcome of incidentally detected small thyroid carcinomas is not proved and because sonography, scintigraphy and fine needle aspiration remain imprecise regarding dignity of incidentalomas, fine needle aspiration is not the standard for small, non-palpable thyroid nodules. Conclusion: For management of incidentaloma, sonographically unsuspicious, scintigraphically indifferent (nodules ≥1 cm) and without any risk factors in patients’ history, wait and see is justified when patient is informed about the problem.

Dominant transmission of prepubertal gynecomastia due to serum estrone excess: hormonal, biochemical, and genetic analysis in a large kindred

Increased extraglandular aromatization has been reported to cause the rare entity of familial gynecomastia. Recently heterozygous inversions at the p450 aromatase gene promotor locus were detected in two different families with this syndrome. We studied a family in which seven affected males over three generations had inherited prepubertal gynecomastia in an autosomal dominant manner. The proband developed gynecomastia at 11.5 yr, entered puberty at 12.5 yr, but was incompletely virilized at 19 yr. A similar development was observed in his affected stepbrother and one first-degree cousin. All three boys had acceleration of prepubertal growth and bone age. The older two had a diminished pubertal growth spurt and precocious growth arrest, but their final heights were within the range of their target height. In addition, the maternal grandfather and three maternal uncles were affected, who all had been mastectomized. The mother of the proband had normal age at menarche and no macromastia. Estrone levels of the proband and the other affected boys were elevated, 17beta-estradiol levels were high-normal, and testosterone levels were low. Hormonal analyses of the affected adults, who had all fathered children, revealed pathologically low serum testosterone levels but normal to high-normal levels of estradiol and estrone. The mother of the proband had elevated estrone levels. Treatment of the proband was more effective with anastrozole than with testolactone and increased the initially reduced testes volume to normal size, promoted virilization, and normalized serum estrone and testosterone levels. Neither preadipocytes from breast fat tissue of the affected stepbrother nor peripheral lymphocytes of the affected boys exhibited increased aromatase activity in culture. Therefore, these cells can be excluded from being the source of estrone excess. In addition, serum of the proband and his stepbrother did not contain factors promoting aromatase activity as assayed using preadipocytes from control individuals.A repeat polymorphism of the p450 aromatase gene cosegregated with the disease phenotype in the family, making a mutation of the p450 aromatase gene likely. Single-strand conformational polymorphism analysis of the known alternative untranslated exons and all coding exons of the p450 aromatase gene did not indicate any mutation. In addition, fluorescent in situ hybridization analysis using four probes covering the promotor region did not reveal the presence of any major inversion at this locus. In conclusion, preadipocytes and blood cells were excluded as the cell source of increased aromatization. Fluorescent in situ hybridization and single-strand conformational polymorphism analyses did not reveal any mutation of the p450 aromatase gene, but an intragenic polymorphic marker cosegregated with the disease phenotype. Excess of serum estrone in the presence of normal 17beta-estradiol levels may be the only indicative serum parameter of this mild manifestation of aromatase excess syndrome, which includes prepubertal gynecomastia and moderate hypogonadism in men but not necessarily short stature. In women, this mode of aromatase excess may remain clinically inapparent.

[The incidentaloma of the thyroid. Over- or underuse of diagnostic procedure for an epidemiologic finding?]

The incidentally detected thyroid nodule using sonography is described as incidentaloma; the most nodules have a diameter up to 1.5 cm. Sonography will detect thyroid nodules in more than 20% of the population in Germany. Epidemiological studies investigating the prevalence of malignancy in such incidentalomas are missing. The incidence of differentiated thyroid cancer is about 3 per 100,000 people and year. However, several monocentric studies have shown a prevalence of malignancy of up to 10% of the thyroid nodules in selected patients' group. The histology did notfound microcarcinomas only, but also small cancer with infiltration of the thyroid capsule, lymph node metastasis or multifocal spread. The studies were not designed for outcome measurement after early and incidental detection of small thyroid cancers. Hypoechogenity, ill defined borders, central hypervascularization or microcalcifications were used as combined criteria for risk stratification. The second method for risk stratification is scintigraphy and further tests are warranted for hypofunctioning nodule > or =1 cm. Additionally, the family history, patient's age <20 years, former radiation of the neck, and measurement of calcitonin should be regarded. Without such a risk stratification selection for fine needle aspiration is impossible. Fine needle aspiration of non-palpable incidentalomas led to non-representative or unequivocal cytological findings in up to 40%. Because better outcome of incidentally detected small thyroid carcinomas is not proved and because sonography, scintigraphy and fine needle aspiration remain imprecise regarding dignity of incidentalomas, fine needle aspiration is not the standard for small, non-palpable thyroid nodules.

CONCLUSION

For management of incidentaloma, sonographically unsuspicious, scintigraphically indifferent (nodules > or =1 cm) and without any risk factors in patients' history, wait and see is justified when patient is informed about the problem.

Synthesis of silver molybdate clusters driven by laser-annealing

The synthesis of silver rich molybdate clusters is achieved by laser induced chemical reaction of coadsorbed MoO(3) and O(2) molecules on free silver clusters. The reactants MoO(3) and/or O(2) molecules condensed at low temperature (77 K-175 K) on free silver clusters. Then, the silver clusters together with their adsorbed molecules are flashed either ionized with a discharge or ionized and heated by a laser. Then they are cooled down by evaporation. The synthesized chemical compounds are analyzed by a high-resolution time-of-flight mass spectrometer. If only one type of reactant is adsorbed on the cluster, only one oxide molecule is stabilized on the metallic core after the heating and cooling cycle. On the contrary, the coadsorption of the two types of molecules MoO(3) and O(2) on Ag(n) (+), at 77 K, leads to complex aggregates that transform, after laser heating, into a molybdate rich metal clusters. These synthesized species cool down by evaporating silver atoms showing evidence of a binary oxide that is more stable than the metallic core. Moreover we demonstrate that for small size molybdate clusters, a stoichiometric composition may differ from the bulk one.

Stem cell clonality and genotoxicity in hematopoietic cells: Gene activation side effects should be avoidable

Two serious adverse events involving activation of the LMO2 oncogene through retrovirus vector insertion in the otherwise extremely successful first gene therapy trial for X-linked severe combined immunodeficieny type 1 (SCID-X1) had initially caused widespread concern in the patient and research communities. Careful consideration 1 year after diagnosis of the second case still finds 12 of the treated patients clearly benefiting from gene therapy (freedom from treatment failure, 80%; survival 100%), a situation that should not portend the end of gene therapy for this disease, and is, in fact encouraging. While current approaches are justified to treat patients with otherwise life-threatening disorders, a broad consensus has developed that systematic basic research is required to further understand the pathophysiology of these serious adverse events and to provide new insights, enabling safer and more effective gene therapy strategies. With the continued success of SCID-X1 gene therapy in the majority of patients treated, it is of even greater importance to understand exactly which vector element or combination of elements predispose to toxicity. An in-depth study of the mechanisms behind the activation of the LMO2 and gammac genes will be highly instructive for the development of safer procedures and vectors. We summarize the central observations, ongoing experimental approaches, new concepts, and developments relevant to understanding, interpreting, and eventually overcoming the real and perceived obstacles posed by insertional mutagenesis due to gene transfer vectors.