Heterogeneity in the ultrastructure of the mucous (goblet) cells of the rabbit palpebral conjunctiva

Aim: The purpose of this study was to assess objectively the ultrastructure of the secretory granules in rabbit conjunctival mucin‐producing ‘goblet’ cells. Method: The upper eyelids from five young adult dioestrous female rabbits were dissected out, stretched onto a cardboard support and prepared for transmission electron microscopy by repeated application of an isotonic two per cent glutaraldehyde fixative at room temperature. Post‐fixation treatment included osmium tetroxide and staining with uranyl acetate and lead citrate. Low magnification micrographs were taken of the goblet cells of the conjunctiva, printed at a magnification of approximately 6,000 and the number, size and features of the secretory granules assessed. Results: Across the entire palpebral conjunctiva of ail five rabbits, the majority of mucous cells displayed a goblet shape and the secretory granules were uniformly pale in staining. The average width of the goblet cells was 10.8 ± 1.1 μm and the diameter of the secretory granules was 0.82 ± 0.16 μm. However, in localised regions across the palpebral conjunctiva of two of the rabbits, some goblet cells were different in that the secretory granules had either a denser‐staining core, in which some of the granules were densely staining (while others were pale) or most of the granules were densely staining. These mucous cells had an average diameter of 10.3 ± 1.7 μm and the granule diameters averaged 0.88 ± 0.01 μm. For these abnormal goblet cells, inflammatory cells were found in their immediate vicinity. Occasionally, goblet cells were seen to be in the process of degranulation with associated apparent cell necrosis and the mucin granule diameter was close to 1 μm. Conclusions: The ultrastructure of the mucin‐containing secretory granules of the conjunctival mucous cells is not necessarily homogeneous in character and further attention needs to be given to the effects of localised inflammation in the tissue and to possible hormonal influences.     

Moderne Verfahren der assistierten Reproduktion

Genetic aspects are becoming more and more important in the diagnostics, patient counselling and therapy of assisted reproduction. Compared to spontaneously conceiving patients, genetic disturbances can be found with a higher incidence in patients requiring these techniques, a fact which is not only due to the greater age of such patients. In several cases, genetic disturbances contribute to or even explain infertility. New insights in the field of pharmacogenetics demonstrate that genetic dispositions influence the success of hormonal stimulation. Furthermore, growing knowledge of potential associations between genomic imprinting and assisted reproduction (ART) demands further attention, especially due to the uncovering of new potential risks of ART itself. Performing genetic diagnosis in oocytes or embryos (preimplantation genetic diagnosis, PGD) warrants further evaluation before it becomes a routine technique.     

From genotype to phenotype--behavior of the transgenic rat TGR(mRen2)27 as an example

Transgenic techniques provide a tool to generate animals that differ from the wild-type by one or more genes, either by introducing foreign genes (transgenic animals) or by specific mutations of genes (knock-out animals). Most transgenic and knock-out animals are mice and not rats. The frequent use of rat models in the behavioral laboratory, however, will require the increasing application of transgenic techniques in this species. This paper reviews behavioral data from our laboratory as an example of characterizing the behavioral phenotype of a particular transgenic rat, the TGR(mRen2)27 rat. By describing the anxiogenic profile of this rat we also consider some problems associated with such an analysis, with the intention to raise issues that may also apply to studies of behavior in transgenic animals in general.     

Value of 8S/4S fractionation of estrogen receptors (ER) for prediction of response to hormonal manipulation in metastatic breast cancer

Summary Using sucrose gradient centrifugation, human breast cancer estrogen receptors appear in two molecular forms sedimenting at either 8S or 4S fractions. The sum of these two fractions has been valuable clinically in helping to predict response to hormonal therapies. It has been suggested that the 4S receptor may not be of predictive value and that the practice of using only dextran-coated charcoal methodology might thus overestimate the number of patients whose tumors might be hormonally dependent. The present study correlates clinical response to hormonal manipulations with 8S and 4S receptors as determined by sucrose density gradient centrifugation. Patients with only 4S positive receptors had a 56% response rate to hormonal manipulation compared with a 52% response rate in patients with positive 8S alone or with both 8S and 4S receptors. Although patient numbers are small in this and the other three published series addressing this question, our data do not confirm two previously published studies suggesting clinical importance of 8S/4S fractionation.     

Responses of human hepatoma HepG2 cells to silver nanoparticles and polycyclic aromatic hydrocarbons

The nanotechnology has revolutionized the global market with silver nanoparticles (AgNP) occupying a prominent position due to their remarkable anti-bacterial properties. However, there is no data about the adverse and toxic effects of associations of AgNP and ubiquitous compounds, such as polycyclic aromatic hydrocarbons (PAH). In the current study, we investigated the responses of HepG2 cells to realistic concentrations of AgNP (0.09, 0.9, and 9?ng ml^?1) and mixture of PAH (30 and 300?ng ml^?1), separately and in association. Cell viability and cytotoxicity (neutral red retention and MTT production assays) and proliferation (crystal violet [CV] assay), xenobiotic efflux transporter activity (rhodamine B accumulation assay), ROS levels (dichlorodihydrofluorescein diacetate assay), and lipid peroxidation (pyrenylphosphine-1-diphenyl assay) were analyzed. There was no decreases of cell viability after exposure to AgNP, PAH and most of AgNP?+?PAH associations, but increases of cell viability/number (CV assay) occurred. Efflux transporter activity was not affected, with exception of one AgNP?+?PAH associations, ROS levels increased, but lipid peroxidation decreased. Some toxicological interactions occurred, particularly for the highest concentrations of AgNP and PAH, but there is no evidence that these interactions increased the toxicity of AgNP and PAH.     

In vivo tumor imaging using a novel RNAi-based detection mechanism

A new concept of tumor imaging is introduced using a siRNA-based probe that is capable of amplifying a specific endogenous fluorescence emission in cancerous tissue. In previous studies, we demonstrated a significant downregulation of Ferrochelatase (FECH) mRNA-expression in colorectal carcinomas leading to the accumulation of protoporphyrin IX (PpIX), a fluorescent metabolite of the heme synthesis. In this article, we report on first in vivo experiments in xenografted nude mice using folate-coupled liposomes or dendritic polyglycerolamine nanoparticles carrying ferrochelatase-siRNA to enhance PpIX-derived fluorescence in the tumor tissue. Tiny tumor foci could be monitored by the emission of PpIX fluorescence in vivo. Due to the omnipresence of the heme synthesis pathway, targeted application of ferrochelatase-siRNA may provide a general means for molecular imaging.From the Clinical EditorA new concept of tumor imaging is presented in this paper using a siRNA-based probe detecting protoporphyrin IX (PpIX), a fluorescent metabolite of the heme synthesis previously demonstrated to accumulate in cancer tissue.