Effects of separated pair housing of female C57BL/6JRj mice on well-being.

In laboratory animal facilities, it is a common code of practice to house female mice in groups. However, some experimental conditions require to house them individually, even though social isolation may impair their well-being. Therefore, we introduced a separated pair housing system and investigated whether it can refine single housing of adult female C57BL/6JRj mice. Individually ventilated cages (IVC) were divided by perforated transparent walls to separate two mice within a cage. The cage divider allowed visual, acoustic, and olfactory contact between the mice but prevented interindividual body-contact or food sharing. Short- and long-term effects of the separated pair housing system on the well-being of the mice were compared with single and group housing using a range of behavioral and physiological parameters: Nest building behavior was assessed based on the complexity of nests, the burrowing performance was measured by the amount of food pellets removed from a bottle, and trait anxiety-related behavior was tested in the free exploratory paradigm. For the evaluation of the ease of handling, interaction with the experimenter's hand was monitored. Social interaction with unknown conspecifics and locomotor activity were investigated in a test arena. Moreover, body weight and stress hormone (metabolites) were measured in feces and hair. After the mice spent a day under the respective housing conditions, concentrations of fecal corticosterone metabolites were higher in separated pair-housed mice, and they built nests of a higher complexity when compared to single-housed mice. The latter effect was still observable eight weeks later. In week 8, separated pair-housed mice showed less locomotor activity in the social interaction arena compared to mice from the other housing systems, i.e., single and group housing. Regardless of the time of testing, pair housing improved the burrowing performance. Separated pair-housed mice were more difficult to catch than group-housed mice. Hair corticosterone, progesterone, and dehydroepiandrosterone concentrations changed with increasing age independently of the housing system. There were no effects of the housing systems on trait anxiety-related behavior in the free exploratory paradigm, voluntary interaction with the experimenter's hand, and body weight. Overall, the transfer to the separated pair housing system caused short-term stress responses in female C57BL/6JRj mice. Long-term effects of separated pair housing were ambiguous. On one hand, separated pair housing increased nesting and burrowing behavior and may therefore be beneficial compared to single housing. But on the other hand, locomotor activity decreased. The study underlined that the effects of the housing conditions on physiological and behavioral parameters should be considered when analyzing and reporting animal experiments.

Elevated risk for MPNST in NF1 microdeletion patients.

An NF1 microdeletion is the single most commonly reported mutation in individuals with neurofibromatosis type 1 (NF1). Individuals with an NF1 microdeletion have, as a group, more neurofibromas at a younger age than the group of all individuals with NF1. We report that NF1 microdeletion individuals additionally have a substantially higher lifetime risk for the development of malignant peripheral nerve sheath tumors than individuals with NF1 who do not have an NF1 microdeletion. This should be taken into account in the medical follow-up of individuals with an NF1 microdeletion.

High telomerase activity is associated with cell cycle deregulation and rapid progression in endometrioid adenocarcinoma of the uterus.

Telomerase activity, a mechanism granting cellular immortality, has been detected in most cancer entities, but its association with clinical, histopathologic, and prognostic parameters is not fully understood. We investigated whether quantitative telomerase levels are correlated to established prognostic factors, telomere lengths, cell cycle kinetics, and the clinical course in endometrioid adenocarcinoma of the uterus (EC). A modified telomeric repeat amplification protocol (TRAP) was used to quantify the relative telomerase activity in a series of 53 primary tumors. Mean telomere length was determined by Southern blot analysis. Cell cycle kinetics were studied immunohistochemically on paraffin sections using monoclonal antibodies to 2 distinct proliferation-specific proteins: Ki-67, which is expressed throughout the cell cycle, and a novel cell cycle-associated protein, repp86, the expression of which is restricted to the cell cycle phases S, G2, and M. The ratio of the 2 immunolabeling indices defines the rate of transition through the restriction point. Telomerase activity was detected in 50 of 53 ECs (94%). Its levels correlated significantly with FIGO stage (P =.01) and FIGO grade (P =.003) but not with myometrial invasion. They were weakly associated with the overall proliferative activity (Ki-67, r =.48) but significantly with the repp86 index (r =.64) and even more strongly with the repp86:Ki-67 ratio (r =.77). There was no correlation with mean telomere length. In the group of tumors with high telomerase activity, 5 patients had relapses and 2 died of the disease within a median follow-up period of 29 months. Recurrence showed no relation to FIGO grade and stage. No events were observed in the group with low telomerase activity. In a multivariate model including tumor stage, histopathologic grade, depth of myometrial invasion, and Ki-67 indices, telomerase activity emerged as the only independent predictor of disease progression (P =.0002). It is concluded that beyond a link to proliferation, high telomerase activity reflects a deregulation of the cell cycle associated with an increased rate of cells entering S phase and a higher degree of malignancy. Therefore, quantitative analysis of telomerase activity may be useful for identifying EC patients at high risk for recurrence.

High proliferative activity may predict early metastasis of thin melanomas.

Metastasis of thin melanomas is uncommon and unpredictable. We prospectively investigated the clinical course of 167 thin melanomas (<1 mm thickness) over a median observation period of 4 years (18 to 87 months). In addition to Breslow thickness, Clark level, and growth phase characteristics, we assessed cellular proliferation by counting mitoses and immunohistochemically using the monoclonal antibody Ki-S5 (Ki-67). Mitotic and Ki-S5 indices were correlated to tumor thickness, Clarks level, and radial/vertical growth phase (RGP/VGP). However, 5 tumors had proliferation indices above 25% (outside the range of a theoretical normal distribution). Four of these tumors metastasized, and none of the melanomas with lower proliferative activity progressed during the observation period. The metastatic behavior was independent of tumor thickness and Clark level and did not unconditionally coincide with VGP or high mitotic counts. It is concluded that the immunohistochemical proliferation index may be a powerful predictor of early systemic progression in thin melanomas, which may be helpful in making therapeutic decisions. Further investigations are needed to determine the value of proliferation measurements for the long-term prognosis of thin melanomas.

Prognostic significance of Ki-67 and topoisomerase IIalpha expression in infiltrating ductal carcinoma of the breast. A multivariate analysis of 863 cases.

To evaluate the prognostic relevance of Ki-67 and topoisomerase IIalpha expression in relation to tumor stage, grade, and hormone receptor content, 942 ductal infiltrating carcinomas of the breast were examined by means of the monoclonal antibodies Ki-S11 (Ki-67) and Ki-S4 (topoisomerase IIalpha). pS2, c-erbB2, and p53 were additionally considered as prognostic variables. The median follow-up time was 149 months. Eight-hundred-and-sixty-three tumors reacted with Ki-S11 and Ki-S4; the labeling indices of the two antigens were closely associated (r = 0.93). Both correlated positively with the tumor size, c-erbB2, and p53 expression, and negatively with patient age, hormone receptor content, and pS2 immunostaining. In the univariate analysis, Ki-S11 and Ki-S4 scores, nodal status, tumor size, tumor grade, and progesterone receptor content strongly predicted both overall and metastasis-free survival (p < 0.00001). Estrogen receptor status, p53, and c-erbB2 were of minor significance. Concerning overall survival, multivariate Cox regression analysis selected a Ki-S4 score >25% (p < 0.00001) next to the nodal status, and before tumor size, progesterone receptor content, and patient age. Independent predictors of the occurrence of distant metastases were nodal status, Ki-S4, tumor size, grade 1, and progesterone receptor negativity, in that order. The Ki-S11 score was of independent prognostic significance only if examined as a continuous variable. We conclude that topoisomerase IIalpha expression as assessed by monoclonal antibody Ki-S4 may add valuable information to current prognostic models for breast cancer. Its predictive value appears to be essentially related to the proliferative activity of tumor cells.

Cell lineage specificity in G-CSF receptor gene methylation.

In hematopoiesis the evolution of specialized cell lineages from a common stem cell is mediated by lineage-specific growth factors. The role of DNA methylation in the multilevel regulation of the differential gene expression, especially in the case of growth factor receptor genes, has remained elusive. In earlier studies we showed a lineage-specific methylation pattern of the M-CSF receptor gene c-fms in blood monocytes and tissue macrophages. Here, we provide evidence that a lineage-specific hypomethylation exists for the G-CSF receptor gene for myelomonocytic cells but not in lymphocytes without any interindividual differences. Constant differences were found between alveolar and peritoneal macrophages with a lesser degree of methylation in peritoneal macrophages. Acute myelomonocytic leukemias showed an increased methylation as compared with normal granulocytes and monocytes. All permanent cell lines analyzed revealed hypermethylation of the G-CSF receptor gene. Lymphocytes of B-CLL showed a strong hypermethylation of this gene. Increased methylation has been shown to be inversely correlated with transcriptional gene activities. We conclude that the methylation pattern of growth factor receptor genes may be one of the regulatory mechanisms in multi-lineage differentiation.

Immunoenzymatic detection of the new proliferation associated protein p100 by means of a cellular ELISA: specific detection of cells in cell cycle phases S, G2 and M.

In vitro proliferation assays are widely used in biomedical research. We describe the immunoenzymatic (ELISA) detection of a recently described proliferation associated protein (p100) by means of a new monoclonal mouse IgG1 antibody (Ki-S2). P100 is a 100 kDa nuclear protein that is specifically detected during the cell cycle phases S, G2 and M. Comparative studies on lectin-stimulated leukocytes using 3H-thymidine labelling and Ki-67 antibodies revealed a statistically significant positive correlation. Since p100 is absent in GO and G1 cells, its detection permits the precise and specific measurement of actual cell cycle events under culture conditions.

Proliferation marker Ki-S11--a prognostic indicator for squamous cell carcinoma of the hypopharynx.

As a potential prognostic factor, the proliferative activity of 131 squamous cell carcinomas (SCC) of the hypopharynx and 47 of their cervical lymph-node metastases was analyzed retrospectively by means of monoclonal antibody Ki-S11 immunostaining, which specifically detects the Ki-67 antigen on paraffin-embedded tissue. Median follow-up time was 37.6 months. Ki-S11 revealed distinctive patterns of proliferating cells related to the degree of differentiation. The proliferation fractions in the primaries and their lymph-node metastases did not differ significantly. Patients with high proliferating hypopharynx carcinomas (>45% labeled cells) had a significantly lower 5-year-survival rate (16%) than patients with low proliferating tumors, whose 5-year-survival rate was 30% (P=0.01). A statistically significant positive correlation was also observed between proliferative activity and lymph-node status (P=0.012). In conclusion, the proliferative activity as determined by means of Ki-S11 immunostaining is of prognostic value with respect to both survival and metastatic risk in SCC of the hypopharynx.

[Intact pregnancy with concomitant hydatidiform mole of a coexisting placenta]. / Intakte Gravidität bei gleichzeitiger Blasenmole einer koexistenten Plazenta.

The simultaneous occurrence of an intact pregnancy with normal placenta morphology and sonographic signs of a hydatidiform mole of a second placenta, which was diagnosed in the 14th gestational week, is described. Prenatal diagnostic and perinatologic management will be reported. The difference of the placentas will be shown by histopathology.

Telomere shortening in uterine leiomyomas.

OBJECTIVE: To gain a better understanding of proliferation control mechanisms in a common benign tumor, we investigated the mean telomere length and the clonality of uterine leiomyomas. STUDY DESIGN: Deoxyribonucleic acid from uterine leiomyomas and from the adjacent normal myometrium of 51 patients (total number of uterine leiomyomas 107; 28 patients with single leiomyoma, 23 patients with multiple leiomyomas ranging from 2 to 8 myoma nodules per case) was hybridized to a telomeric oligonucleotide probe by Southern blot and chemiluminescent detection. The mean telomere length was evaluated by densitometry. Clonality was assessed with use of the phosphoglycerokinase gene polymorphism. RESULTS: The mean telomere length was significantly shorter in uterine leiomyomas (median 7950 bp, interquartile range 7261 to 8372 bp) than in normal myometrium (median 9688 bp, interquartile range 8528 to 10535 bp) (P < .001). There was no correlation between tumor size and telomere attrition. Multiple uterine leiomyomas were found to have an independent clonal origin. CONCLUSIONS: Telomere attrition in uterine leiomyomas reflects enhanced proliferation activity in the course of tumor evolution. The basic telomere lengths differ in the myocytes from which the uterine leiomyomas originate, probably explaining the lack of correlation between telomere attrition and tumor size.

Improved ELISA proliferation assay (EPA) for the detection of in vitro cell proliferation by a new Ki-67-antigen directed monoclonal antibody (Ki-S3).

We describe a simplified and improved proliferation assay based on a conventional ELISA system for the in vitro measurement of cellular proliferation (ELISA proliferation assay = EPA). The assay is based on a new monoclonal antibody (Ki-S3) to the proliferation-specific Ki-67-antigen and is carried out in 96-well microtiter plates using conventional immunoenzymatic methods. Ki-S3 is an immunoprecipitating monoclonal mouse IgG1 antibody, which recognizes a formalin-resistant epitope of the Ki-67 antigen. It can be used to measure proliferating cells in the cell cycle phases G1, S, G2 and M. In phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) the absorbance values obtained with the EPA show a statistically significant correlation to the number of Ki-S3 positive cells in simultaneously immunostained cytospin slides (r = 0.88). A direct comparison with [3H]thymidine labeling reveals the test to be an equally sensitive method for monitoring cellular proliferation (r = 0.91). This assay is an improved ELISA proliferation assay, which is easy to perform, does not require time-consuming pretreatments and avoids the hazards of radioactive isotopes.

Sinus-lining cells of the lymph nodes recognized as a dendritic cell type by the new monoclonal antibody Ki-M9.

In the immunobiological characterization of lymph node cells, sinus-lining cells (SLCs) have been given little attention mainly due to the difficulties in their recognition. Ki-M9 is a new monoclonal antibody (MAb) selected for its unique capability to visualize SLCs in human lymph nodes. The details were established by light and electron microscopy and immunoprecipitation of the corresponding biosynthetically labeled antigen. Ki-M9 recognizes a 70-kd protein localized on the surface membrane of SLCs. In the lymphoid tissue, a mild reactivity was exclusively encountered on follicular dendritic reticulum cells in the germinal centers of secondary lymphoid follicles. In other organs, some squamous epithelial and myoepithelial cells were recognized by this antibody. Immunomonitoring of SLCs on light and electron microscopic levels revealed their dendritic morphology, lack of phagosomes, and their close association with type IV collagen fibers. Considering the occurrence of typical dendritic SLCs on the front line of antigen flood, we propose that SLCs be investigated for a possible antigen-binding property.