Atypical hatching of a human blastocyst leading to monozygotic twinning: a case report.

OBJECTIVE: To report a case of monozygotic twinning after atypical hatching of a human blastocyst. DESIGN: Case report. SETTING: University-based IVF program. PATIENT(S): A 33-year-old woman with tubal sterility. INTERVENTION(S): Embryo transfer of a human blastocyst with atypical hatching. MAIN OUTCOME MEASURE(S): Development to the blastocyst stage, hatching process, follow-up of pregnancy. RESULT(S): Development of a monozygotic dichorial pregnancy. CONCLUSION(S): First report of an atypical hatching of a human blastocyst leading to dichorial monozygotic twinning.

The relationship between ovarian vascularity and the duration of stimulation in in-vitro fertilization.

The role of transvaginal pulsed colour Doppler ultrasound in the assessment of ovarian vascularity was studied in 196 in-vitro fertilization (IVF) cycles. The changes in ovarian blood flow after gonadotrophin-releasing hormone agonist (GnRHa) down-regulation and human menopausal gonadotrophin (HMG) stimulation were determined. The data obtained showed that the ovarian blood flow was significantly improved by oestradiol secretion (P = 0.05) and human chorionic gonadotrophin (HCG) administration (P = 0.003). Folliculogenesis was affected by blood flow supply. The resistance index (RI) value was significantly different (P = 0.05) according to the duration of ovarian stimulation. Patients with a mean RI value >0.56 had a longer stimulation with a significantly lower mean number of oocytes retrieved (P = 0.01) despite the administration of a standard dose of HMG. The RI value is a good indicator of modifications in ovarian vascularization during stimulation. Doppler blood flow measurement could be used to determine the optimal timing for the beginning of HMG administration in patients undergoing ovarian stimulation after down-regulation for IVF treatment.

Predictive factors for multiple pregnancy in in vitro fertilization.

OBJECTIVE: To study predictive factors influencing the multiple pregnancy rate in in vitro fertilization (IVF). STUDY DESIGN: Retrospective study. RESULTS: In 1,736 IVF cycles, 453 pregnancies occurred. The rate of singleton, twin and triplet pregnancies was 44%, 22% and 4.5%, respectively. Eighty-one percent of these clinical pregnancies ended with a delivery, giving a "take-home baby" rate of 23.8%/oocyte retrieval. As expected, a statistically significant positive correlation was found between the number and quality of embryos replaced and the occurrence of multiple pregnancies. A statistically significant correlation was also found when parameters such as age, stimulation parameters and embryo characteristics were incorporated into the analysis. This correlation was different for singleton, twin and triplet pregnancies. CONCLUSION: Based on the findings of this study, in patients with a good prognosis for IVF outcome, only two embryos of good quality should be replaced regardless of the maternal age or number of IVF attempts.

A unilateral hydrothorax as the only manifestation of ovarian hyperstimulation syndrome: a case report.

OBJECTIVE: To describe a rare case of unilateral hydrothorax occurrence after ovarian stimulation for IVF. DESIGN: Case report. SETTING: A university hospital. PATIENT(S): A 39-year-old female suffering from primary infertility due to a severe male factor. INTERVENTION(S): Thoracocentesis with IV albumin administration for correction of a concomitant hypoalbuminemia. MAIN OUTCOME MEASURE(S): Laboratory values of hematologic measures and electrolytes, screening of the thoracic fluid aspirated for viral and bacterial infections, resolution of pleural effusion after the second thoracocentesis as determined by chest roentgenogram. RESULT(S): Treatment of this manifestation of the ovarian hyperstimulation syndrome (OHSS) by thoracocentesis with albumin perfusion. CONCLUSION(S): This report describes a very rare case of thoracic complication after ovarian stimulation. It demonstrates that pleural effusion may be the only manifestation of the OHSS and implies a careful management of patients with pulmonary complaints after treatment with exogenous gonadotropins.

Metastasis of mouse T lymphoma cells is controlled by the level of major histocompatibility complex class I H-2Dk antigens.

In vivo inoculation of a low metastatic BW 5147 derived T-cell lymphoma variant into syngeneic mice, had led to the generation of a highly metastatic variant. The shift towards a more metastatic phenotype is accompanied by an increase in major histocompatibility class I H-2Dk antigen expression. This suggests that H-2Dk antigens may control the metastatic potential of BW T lymphoma cells. Our present findings indicate that H-2Dk expression is directly correlated with the metastatic potential of BW cells. We have confirmed such correlation by specifically altering the level of H-2Dk expression by: 1) FACS analysis, 2) IFN-gamma treatment, 3) H-2Dk gene transfection. Cells sorted for low H-2Dk expression had a significantly reduced metastatic potential. Induction of H-2Dk expression on these cells by either IFN-gamma treatment or H-2Dk gene transfection concomitantly led to increased metastasis. We also assessed metastatic potential of BW cells in irradiated, immunocompromised recipients. Our results show that the immune system is implicated and we further tested which immune effectors are involved. In vivo depletion of natural killer (NK) and CD8+ T-cells revealed that the difference in metastatic potential of the H-2Dk variants relies upon an NK-dependent mechanism, whereas CD8+ T-cells are not implicated. Our observations suggest that highly metastatic cells, expressing a high level of H-2Dk antigens are more resistant to NK-cell-mediated cytotoxicity in vivo. We have confirmed our in vivo results by in vitro cytotoxicity assays using poly I:C induced NK and IL-2 activated LAK cells. We conclude that a NK-dependent mechanism accounts for the association between differential H-2Dk antigen expression and metastasis.

The role of the spleen in the organ-specific metastasis of murine BW 5147 T lymphomas.

Organ-specific metastasis of tumour cells may result from selective invasion and growth or from selective host cell responses. The present study demonstrates how selective interactions with the host affect the metastatic pattern of two murine T cell hybridoma lines, derived from the BW 5147 thymoma. Upon intravenous inoculation into syngeneic mice BW-14 cells preferentially colonize the kidneys, whereas BW-19 cells metastasize mainly to the spleen and the liver. The organ-specific behaviour of the two cell lines appears to be determined by a differential interaction with the spleen microenvironment. Inoculation of BW-14 cells into splenectomized mice results in increased liver colonization, indicating a negative effect of the spleen on BW-14 tumour development in the liver. Macrophages are likely to be involved in this inhibition, since inoculation of BW-14 cells into macrophage-depleted mice also leads to increased liver and spleen metastasis. In contrast, inoculation of BW-19 cells into splenectomized mice results in decreased liver metastasis, which indicates that the spleen exerts a stimulating effect on BW-19 cells. Macrophages also appear to be involved in this stimulation, since macrophage depletion causes a similar decrease in liver and spleen colonization. Hence components of the splenic microenvironment, probably macrophages, exert inhibiting or stimulating activities on BW-14 or BW-19 cells respectively, thereby determining the subsequent liver or kidney colonization.

Tumorigenicity of mouse T lymphoma cells is controlled by the level of major histocompatibility complex class I H-2Kk antigens.

We have previously found that an increased tumorigenicity and spontaneous metastatic potential of BW5147-derived T lymphoma cells was associated with a decrease in major histocompatibility complex (MHC) class I H-2Kk antigen expression. This suggested that H-2Kk antigens may control the tumorigenic potential of BW T lymphoma cells. Our current experiments aimed to prove this association by specifically altering H-2Kk expression by gene transfection. Transfected cells expressing a high level of H-2Kk antigens were significantly less tumorigenic and metastatic after subcutaneous inoculation. However, there was selection in vivo for cells expressing a reduced level of H-2Kk antigens, which concomitantly led to an increased tumorigenicity. These data further confirmed the strong association between H-2Kk expression and tumorigenicity. We subsequently tested whether the immune system is implicated in this phenomenon by inoculating the H-2Kk transfectants into irradiated, immunocompromised recipients. Our results indicate that the reduced tumorigenicity of the BW H-2Kk transfectants is due to an immune rejection mechanism, mediated by CD8+ immune effector cells, as revealed by in vivo depletion experiments with anti-CD8 antibodies. Hence, we hereby demonstrated that H-2Kk antigens increased the immunogenicity of BW cells, via a CD8-dependent mechanism, which consequently reduced their tumorigenicity.

Thymic nurse cells in culture: morphological and antigenic characterization.

Epithelial monolayers were derived from thymic nurse cells (TNC), and were seeded onto collagen-coated dishes immediately after their isolation from young adult C3H-murine thymuses. Different media and supplements were tested in order to obtain cultures that were as pure as possible. Primary cultures were enriched in epithelial cells but always contained non-epithelial components among which fibroblasts predominated. Immunodetection of keratins, and repeated light- and electron-microscopic observations established the epithelial nature of the elongated cells derived from TNC; these elongated cells were cortical reticular cells, and were different from medullary globular cells that immediately adopted a mosaic pattern in vitro. At the beginning of the culture, the necrosis of cortical lymphocytes appeared to be toxic for epithelial cells; when epithelial cells survived, they showed a temporary lipid accumulation. After a 5-day culture, they still synthesized DNA but lost this capacity thereafter and dedifferentiated. The lympho-epithelial symbiosis appeared to be necessary to maintain some epithelial characteristics of the cultured cells, such as the clear vesicles and the expression of Ia antigens. In sub-cultures, the monolayers were almost purely epithelial in nature but growth was no longer observed. The cells remained reticular in shape, as they were in vivo, but their cytoplasm and their nucleus became larger and numerous cells were multinucleated. Confluence was not obtained with classical media even after mitogenic stimulation. The frequent observation of strongly keratinized areas suggested a process of terminal differentiation; this could not be avoided by using low serum concentration.

Thymic accessory cell complexes in vitro and in vivo: morphological study.

Murine thymic macrophages and interdigitating cells, also called thymic accessory cells, were characterized by means of light- and electron microscopy. The cells were studied in suspension, during isolation by enzymatic digestion and in vivo. They were observed as isolated cells or as components of multicellular complexes, some of which were rosettes and were composed of lymphoid cells centered on each type of accessory cell. We also noted other cell complexes including macrophages that resembled classical epithelial nurse cells. We consider that multicellular complexes represent lymphostromal associations already existing in vivo, because we observed them at the periphery of thymic pieces undergoing enzymatic treatment. The heterogeneity of macrophages that we observed in vitro was also noted in vivo. In vivo macrophages were of three types: classical phagocytic cells distributed throughout the gland, cortical elongated cells in close contact with lymphoid blast cells, and atypical nurse cells containing mitotic cells and located in the inner cortex. The morphological aspects of the latter two cell types suggest that cortical macrophages in vivo have other roles: they can be interpreted as images of positive or negative cell selection. We also believe that rosettes are formed by elongated cortical macrophages when they are enzymatically isolated from the thymus.

Thymic nurse cells: morphological study during their isolation from murine thymus.

Thymic nurse cells (TNC), which are multicellular complexes composed of epithelial cells and thymocytes, were obtained from C3H-mice thymuses. They were described by means of light and electron microscopy. The morphology of epithelial cells forming isolated TNC compared to that of small tissue fragments obtained by enzymatic digestion revealed that TNC could be derived from all parts of the thymus: cortex, corticomedullary junction and medulla, the cortex being their principal source. This variety of origin, the presence of several epithelial cells inside a single TNC, the presence of non-lymphoid cells, and the various locations of cleaved desmosomes confirmed that their aspect "in vitro" as round and sealed structures can be considered to be an artifact due to the isolation technique used. Indeed, during this procedure, they are formed by a process of wrapping of the epithelial cytoplasm around the tightly associated thymocytes. All three epithelial cell types: cortical reticular cells, medullary reticular cells, and medullary globular cells can form TNC.

Effects of iodide on class II-MHC antigen expression in iodine deficient hyperplastic thyroid glands.

The expression of major histocompatibility complex class II molecules (Ia antigen) has been analyzed by immunoperoxidase staining in thyroids of normal C3H mice, of iodine-deficient mice with a hyperplastic goiter and of mice during goiter involution induced by administration of either a high iodide dose (HID, 10 micrograms/day) for 0.5 to 8 days or a moderate iodide dose (MID, 1 microgram/day) or triiodothyronine (T3, 1 micrograms/day) for 2 days. In normal and in hyperplastic thyroids, few interstitial cells were Ia positive (monoclonal antibodies, mAb, M5/114, ER-TR3). Their number was unchanged when goiter involution was induced by MID or by T3, but was significantly increased (p less than 0.05) after HID. It was maximal at days 1 and 2 of involution, decreased thereafter but remained higher (p less than 0.05) than in controls after 8 days. The Ia positive cells were mainly macrophages and, to a lesser extent, dendritic cells. Macrophages were identified by their heterogeneous content and their numerous lysosomes. They were stained with anti-Mac-1 (M1/70) and anti-Mac-2 (M3/38) mAb. Dendritic cells were characterized by their slender cytoplasmic processes, indented nucleus and pale cytoplasm. They were positive for NLDC-145 and MIDC-8 mAb whose specificity for dendritic cells has been demonstrated in lymphoid organs. During the whole period of involution analyzed, Ia antigens were not expressed on follicular cells. Since macrophages and dendritic cells are known to be involved in the pathogenesis of immune disorders, the inflammation induced by administration of HID to iodine-deficient mice could be considered as the early step of an immunological reaction.