Cadmium embryotoxicity: evidence of a direct effect of cadmium on early rat embryos.
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Animals↗
Biomedical subjects
A Fein
Publications and source records attributed to A Fein.
[Ca2+]i oscillations and [Ca2+]i waves in rat megakaryocytes.
ATP activated [Ca2+]i oscillations were measured in single rat megakaryocytes using fluorescence ratio microscopy. With increasing ATP concentration the duration of the [Ca2+]i oscillations increased, however, there was considerable variation from cell to cell in the absolute value of the peak [Ca2+]i and the frequency and duration of the oscillations. This variation depended, in part, on the level of Fura-2 loading suggesting that megakaryocytes are sensitive to buffering of [Ca2+]i by Fura-2. Agents, that increase the level of intracellular cGMP (sodium nitroprusside and 8-pCPT-cGMP) or cAMP (prostacyclin, IBMX, forskolin and 8-bromo-cAMP) inhibited [Ca2+]i oscillations. Despite the large cell to cell variation in the patterns of [Ca2+]i oscillations, reapplication of the agents that elevated cAMP or cGMP inhibited the oscillations similarly. Using video rate fluorescence ratio imaging we found that the agonist-induced [Ca2+]i oscillations were the result of a well-defined [Ca2+]i wave, which spread across the cell with an average speed of about 35 microns/s, during the rising phase of each oscillatory spike. After reaching a peak, [Ca2+]i decreased uniformly across the whole cell during the falling phase of the spike. Analysis of the temperature dependence of [Ca2+]i waves showed that the rate of [Ca2+]i decay exhibited a strong temperature dependence (Q10 approximately 4), whereas, the rate of rise exhibited a weak temperature dependence (Q10 approximately 1.3), suggesting, that the rate limiting process for [Ca2+]i wave propagation in rat megakaryocytes is the rate of [Ca2+]i diffusion.
Adenosine Triphosphate↗
Use of antibodies against the human antigen of erythroblasts for the detection of nucleated erythrocytes in the maternal circulation.
In the present study, we tried to detect nucleated erythrocytes in maternal blood by means of the HAE9 antibody that binds to the antigen of erythroblasts (Ag-Eb) on nucleated erythroid cells. Umbilical cord blood and placental cells, which are known to contain a high number of nucleated erythrocytes, indeed demonstrated a high percentage of Ag-Eb-positive cells. In comparison, HAE9 stained up to 4.5% of the peripheral blood cells collected from pregnant women, but not those of nonpregnant women or normal men. These results, demonstrating a simple and reliable method for the identification of nucleated erythrocytes in the maternal circulation using the anti-Ag-Eb antibody, might open new possibilities for the detection of nucleated erythrocytes in maternal blood.
Antibodies, Monoclonal↗
In vivo evidence for the existence of a threshold for hyperglycemia-induced major fetal malformations: relevance to the etiology of diabetic teratogenesis.
The present study was carried out to evaluate whether hyperglycemia-induced major fetal anomalies are thresholded phenomena. Streptozotocin (STZ)-treated female ICR mice were examined on day 19 of pregnancy by methods routinely used in Segment II teratological studies. Simultaneously, the glucose and hemoglobin A1c (HbA1c) levels in maternal-blood were measured and mice with glucose levels > 9.5 mmol/l (mean + 3 SD) were considered to be diabetic. The occurrence of litters with fetuses having gross structural anomalies was clearly associated with glucose levels > 27.8 mmol/l. A wide range of HbA1c levels (between 6 and 18 SD above the mean) were observed, within which only single malformed fetuses were found in the litters of diabetic females. A decreased pregnancy rate in diabetic ICR mice was associated with glucose levels > 16.7 mmol/l and with HBA1c levels > 6 SD above the mean. The results of this study suggest that there is a threshold glucose level associated with a clear increase of the number of litters with severely malformed fetuses in diabetic ICR mice. Results of this study also suggest the existence of HbA1c-associated factors determining, along with glucose, the teratogenic response of ICR mice to diabetes. The interpretation of results obtained in terms of the multifactorial/threshold model leads to the hypothesis that the teratogenic potential of diabetes may consist of two components; one associated with 'direct' teratogens perturbing developmental processes in embryos at a 'critical moment' in organogenesis, and a second component, associated with a direct or indirect influence of the diabetic environment on developmental processes in the preimplantation embryos.
Animals↗
Teratogen-induced apoptosis may be affected by immunopotentiation.
Intra-uterine immunization of mice with paternal allogeneic or xenogeneic (rat) splenocytes was found to increase embryo tolerance to cyclophosphamide (CP)-induced teratogenesis. As the CP-induced teratogenic effect was shown to be associated with apoptosis, the present study was designed to investigate whether the protective effect of immunopotentiation may be realized via an alteration of CP-induced apoptosis. Various doses of CP were injected intraperitoneally into ICR mice on day 12 of pregnancy. Intra-uterine immunization with xenogeneic rat splenocytes was carried out 3 weeks before mating. Implantation sites, resorptions, live and dead fetuses, as well as soft tissue anomalies and external malformations, were recorded to evaluate the CP-induced embryotoxic effect. In parallel, flow cytometric analysis and DNA fragmentation assay were used for evaluation of CP-induced apoptosis in limbs, tail and whole embryos. The treatment of mothers with a high dose of CP induced the death of almost all embryos and striking fetal growth retardation in survivors. This strong embryotoxic effect was accompanied by very prominent DNA degradation in cells collected from whole embryos. Immunostimulation caused a dramatic decrease of embryonal loss (by approximately 50%) and a significant (about 30%) increase in fetal weight. Such an increase in fetal survival and in fetal weight was found to be accompanied by a clear decrease in apoptosis level in embryo cell population as judged by DNA gel electrophoresis with subsequent quantitation of DNA fragmentation in negatives by an image analysis technique. After treatment with a low dose of CP, a decrease in the proportion of fetuses with limb and tail anomalies in immunized females was accompanied by a decrease in the proportion of apoptotic nuclei in cells taken from limbs and tails. The results of this study suggest that the teratogen-induced apoptosis may, at least partly, be dependent on fetomaternal immune interactions.
Adjuvants, Immunologic↗
Kinetics of oxygen consumption and light-induced changes of nucleotides in solitary rod photoreceptors.
We made simultaneous measurements of light-induced changes in the rate of oxygen consumption (QO2) and transmembrane current of single salamander rod photoreceptors. Since the change of PO2 was suppressed by 2 mM Amytal, an inhibitor of mitochondrial respiration, we conclude that it is mitochondrial in origin. To identify the cause of the change of QO2, we measured, in batches of rods, the concentrations of ATP and phosphocreatine (PCr). After 3 min of illumination, when the QO2 had decreased approximately 25%, ATP levels did not change significantly; in contrast, the amount of PCr had decreased approximately 40%. We conclude that either the light-induced decrease of QO2 is not caused by an increase in [ATP] or [PCr], or that the light-induced change of [PCr] is highly heterogeneous in the rod cell.
Adenosine Triphosphate↗
The effect of cyclophosphamide on rat blastocysts in vitro and their subsequent development following transfer to pseudopregnant rats.
These investigations were undertaken to assess the effects of cyclophosphamide (CPA) on rat blastocysts. In the first set of experiments, blastocysts were exposed to 100 micrograms/ml CPA in culture for 48 h. In the second experiment, blastocysts were cultured for 48 h following injection of 20 or 40 mg/kg of CPA to pregnant rats on day 4 of gestation. In the third experiment, blastocysts were cultured for 2 h in the presence of 100 micrograms/ml of CPA and then transferred to pseudopregnant rats. The results from the first experiment revealed a clear toxic effect of CPA on blastocysts following culture. A similar effect occurred when blastocysts were harvested and cultured following in vivo injections of CPA. In the third experiment a clear embryotoxic effect (larger number of resorptions and retarded embryos in comparison to control) was found on day 13 of gestation. The origin of activation of CPA by the blastocysts could not be ascertained from the above results.
Animals↗
Suppression of the delayed rectifier type of voltage gated K+ outward current in megakaryocytes from patients with myelogenous leukemias.
In normal human megakaryocytes, we identified a delayed rectifier type of voltage-gated outward K+ current (DRK). In two human megakaryoblastic tumor cell lines (DAMI, CHRF-288-11) and the human erythroleukemia cell line (HEL) the DRK current was not detected. To determine if the absence of the DRK current in the tumor cells is the result of the underlying malignant state, we examined megakaryocytes from myelogenous leukemia patients. In 24 of 29 megakaryocytes from the myelogenous leukemia patients, the DRK current was greatly suppressed, whereas in the remaining 5 megakaryocytes a normal large amplitude DRK current was present. We had the opportunity to reexamine megakaryocytes from a patient with acute promyelocytic leukemia (M3), after chemotherapy. Whereas the DRK current was suppressed before treatment, the current reappeared after chemotherapy. Exposure to the adenylate cyclase activator, forskolin, caused the appearance of a voltage-gated outward current in the megakaryocytes of patients with acute myelogenous leukemia. This finding suggests either that the channels underlying the DRK current are present but somehow suppressed in megakaryocytes from these patients or that forskolin induces a different voltage-gated outward current. We suggest that the megakaryocytes from the myelogenous leukemia patients with suppressed DRK current are abnormal, whereas the others may be normal megakaryocytes. The suppression of the DRK current may be a contributory factor to the dysregulation of thrombopoiesis (Zittoun et al: Semin Hop Paris 44:183, 1968 and Rabellino et al: Blood 63:615, 1984) in myelogenous leukemias.
Animals↗
Cyclophosphamide-induced teratogenesis in ICR mice: the role of apoptosis.
It is known that programmed cell death (apoptosis) is an important physiological determinant of embryonic development. In parallel, it may be one of the major events involved in induced teratogenesis. The present study was designated to evaluate to what extent is apoptosis involved in the formation of some final abnormalities induced by cyclophosphamide (CP) in ICR mice. The level of apoptosis in limbs, tail, liver, and whole embryo was assessed 24 h after administration of various doses of CP (day 12 of pregnancy) by flow cytometric analysis and by DNA fragmentation assay. In parallel, the rate of limb and tail malformations, resorptions, and growth retardation induced by various doses of CP was evaluated in animals sacrificed on day 19 of pregnancy using routine teratological methods. A striking correlation between the rate of CP-induced apoptosis in limb and tail cells and the severity of limb and tail anomalies was found after administration of CP ranging from 10 to 40 mg/kg. Thus, the percent of apoptotic cells collected from limbs and tails increased from 18 to 78%. In parallel, the severity of limb and tail anomalies increased from digit anomalies to amely and from crooked to short or absent tail. CP-induced embryolethality and fetal growth retardation also correlated with the level of apoptosis in cells collected from whole embryos but to a lesser extent. These results claim that CP-induced apoptosis is one of the inevitable events in the pathway leading to the formation of CP-induced abnormalities and also suggest that the extent of the involvement of apoptosis in the formation of different types of final abnormalities, may be different.
Abnormalities, Drug-Induced↗
Evaluation of serum-associated embryotoxicity in women with reproductive disorders.
PURPOSE: Our purpose was to determine whether some cases of infertility may be due to serological factors inhibiting development of the embryo. METHOD: We examined the effect of infertile women's sera on the expansion, attachment, and spreading of mouse blastocysts in culture. Cell marker expression was also assayed by an indirect immunofluorescence technique. Serum samples from 75 infertile women were compared to the effect of 24 control AB sera. RESULTS: After 72 hr, blastocyst spreading was significantly different depending on whether cultured in sera from women with unexplained infertility, anovulatory infertility, diethylstilbesterol exposure or controls. Neither sera from women with mechanical infertility (14) nor sera from women with endometriosis (8) affected blastocyst growth in culture. CONCLUSIONS: Inhibitory sera were capable of reducing cytokeratin expression but had no effect on placental alkaline phosphatase or concanavalin A expression by blastocyst cells. It can be inferred that the inhibitory effect of sera from women with certain types of infertility might be due to damage to the cytoskeleton. This in vitro assay may predict the success or failure of IVF.
Adult↗
Immunoteratology: I. MHC involvement in the embryo response to teratogens in mice.
PROBLEM: The present study was carried out to evaluate an involvement of MHC-associated maternal immunoreactivity in response to environmental teratogens. METHODS: Two chemicals, cyclophosphamide (CP) and 2,3-quinoxalinedimetanol, 1,4-dioxide (QD) were used as the reference teratogens (RT). The response to these RT was investigated in syngeneically and allogeneically mated CBA/J and C57B1/6 mice. In part of C57B1/6 female mice, paraaortic lymph nodes were extirpated 14 days before mating to allogeneic or syngeneic males. Twenty or 40 mg/kg of CP or 300 or 600 mg/kg of QD were injected on day 12 and 9 of pregnancy, accordingly (vaginal plug indicates day 1 of pregnancy). On day 19 of pregnancy implantation sites, resorption, live and dead fetuses were recorded and live fetuses were examined with methods routinely used in applied teratology. RESULTS: Both mice strains showed equal response to teratogens but the RT-induced effect was significantly weaker in allogeneic than syngeneic mouse combinations. Extirpation of draining lymph nodes dramatically increased the sensitivity to RT in allogeneically mated females but failed to alter that of syngeneically mated ones. CONCLUSION: The results of this study suggest that fetomaternal MHC incompatibility exerts the favourable influence on teratological resistance of the embryo and MHC-associated immunoreactivity of "mother-fetus" axis is possibly responsible for this effect.
Abnormalities, Drug-Induced↗
[Experimental microendoscopy of the milk duct system (ductoscopy)].
According to recent reports, the microendoscopic lactiferous duct investigation (ductoscopy) could improve diagnosis in case of pathological nipple discharge. However, the description of a reproducible and reliable methodology, suitable for thorough evaluation of the lactiferous duct is missing so far. Therefore, the pressure study developed a procedure, that may serve now as an experimental basis for further clinical evaluation. Access to the mamillary duct is primarily gained using atraumatic flexible teflon catheters. Corresponding to the diameter of the duct, either a semirigid 0.87 mm fiberendoscope can be successfully introduced via a 1.2 mm catheter, or a flexible 0.50 mm fiberendoscope via a 1.0 mm catheter. A controlled distension using few milliliters of ringer's lactate is the prerequisite for clear visualization of the intraductal space and protection against iatrogenic wall lesions. Metal microtocars are available as prototypes. They carry a somewhat higher risk to perforate, but are advantageous when pointing at an intraductal structure and using the microtrocar as a mark for microdochectomy.
Animals↗
Continuous network of endoplasmic reticulum in cerebellar Purkinje neurons.
Purkinje neurons in rat cerebellar slices injected with an oil drop saturated with 1,1'-dihexadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate [DiIC16(3) or DiI] to label the endoplasmic reticulum were observed by confocal microscopy. DiI spread throughout the cell body and dendrites and into the axon. DiI spreading is due to diffusion in a continuous bilayer and is not due to membrane trafficking because it also spreads in fixed neurons. DiI stained such features of the endoplasmic reticulum as densities at branch points, reticular networks in the cell body and dendrites, nuclear envelope, spines, and aggregates formed during anoxia nuclear envelope, spines, and aggregates formed during anoxia in low extracellular Ca2+. In cultured rat hippocampal neurons, where optical conditions provide more detail, DiI labeled a clearly delineated network of endoplasmic reticulum in the cell body. We conclude that there is a continuous compartment of endoplasmic reticulum extending from the cell body throughout the dendrites. This compartment may coordinate and integrate neuronal functions.
Animals↗
Three-dimensional organization of endoplasmic reticulum in the ventral photoreceptors of Limulus.
Living Limulus ventral photoreceptor cells were injected with long chain lipophilic carbocyanine fluorescent dyes to label the endoplasmic reticulum (ER). The purpose of this study was to examine the continuity, dynamic changes, and structure of the ER in the living cell, using laser scanning confocal microscopy and three-dimensional image reconstruction. In this highly polarized neuron, three lines of evidence indicate that the ER is a continuous network extending throughout both lobes of the cell. First, injection of DiO or DiI results in the labeling of ER throughout both lobes of the cell. Second, three-dimensional image reconstruction of the optical sections reveals a dispersed membrane meshwork which may be the structure that serves to interconnect the ER in the two lobes. Third, in cells fixed before dye injection, the pattern of labeling was similar to that in living cells, indicating that vesicle transport was not responsible for the spread of dye throughout the cell. The overall organization of the ER in the photoreceptor cell is relatively stable; however, the fine structure changes over time. This dynamic process appears to represent continual reorganization of the intracellular membranes in the cell. Three morphological types of ER were observed. The ER of the light-sensitive lobe, identified by coinjection of rhodamine-phalloidin to label the microvillar actin, is characterized by a concentration of stratiform membranes interconnected by thin tubular cross-bridges. The perinuclear ER is characterized by a tangle of convoluted tubules sometimes terminating in bulbous structures. Finally, there is a fine tubular reticulum dispersed throughout the cell.
Animals↗
MHC-associated immunopotentiation affects the embryo response to teratogens.
The present study was performed to evaluate whether the effect of environmental teratogens can be modified by maternal immunostimulation. Two chemicals, cyclophosphamide (CP) and 2,3-quinoxalinedimetanol,1,4-dioxide (QD) were used as the reference teratogens (RT). The response to these RT was investigated in two animal models: (i) primigravid C57Bl/6 mice who underwent intrauterine immunization with allogeneic paternal (CBA/J), third-party (BALB/c) or syngeneic male splenocytes 21 days before mating; (ii) C57Bl/6 and CBA/J mice who were treated with RT during the second pregnancy only, after a different mating combination (syngeneic or allogeneic) in the first and the second pregnancy. Different doses of CP and QD were injected on days 12 and 9 of pregnancy, respectively. On day 19 of pregnancy implantation sites, resorptions, live and dead fetuses were recorded and live fetuses were examined for external and internal malformations with methods routinely used in teratological study. It was shown that intrauterine immunopotentiation with allogeneic paternal splenocytes clearly enhances the tolerance of F1 embryos to RT. Thus, in CP-treated females the resorption rate and the proportion of malformed fetuses were significantly reduced. It was followed by an almost two-fold increase in fetal weight. The protective effect of such immunization in QD-treated females was manifested as a dramatic decrease of the proportion of malformed fetuses and the resorption rate. Syngeneic splenocytes could not significantly influence an embryo's sensitivity to RT. The response to RT was also significantly weaker in the second pregnancy of female mice mated twice allogeneically than that observed in allogeneically mated primigravid mice. These results show that the embryo's response to environmental teratogens may be influenced by fetomaternal immune interactions.
Abnormalities, Drug-Induced↗
Excitation induced by acetylcholine after injection of Limulus ventral photoreceptor with ml muscarinic receptor mRNA.
We investigated whether a human neurotransmitter receptor for acetylcholine (Ach) could couple Ach to light-sensitive pathways in Limulus photoreceptors. Two to three days after injection of human ml muscarinic mRNA into Limulus ventral photoreceptors the cells depolarized in response to Ach.
Acetylcholine↗
Visual pigment bleaching in isolated salamander retinal cones. Microspectrophotometry and light adaptation.
Visual pigment bleaching desensitizes rod photoreceptors greatly in excess of that due to loss of quantum catch. Whether this phenomenon also occurs in cone photoreceptors was investigated for isolated salamander red-sensitive cones. In parallel experiments, (a) visual pigment depletion by steps of bleaching light was measured by microspectrophotometry, and (b) flash sensitivity was measured by recording light-sensitive membrane current. In isolated cones, visual pigment bleaching permanently reduced flash sensitivity significantly below that due to the reduction in quantum catch, and there was little spontaneous recovery of visual pigment. The "extra" desensitization due to bleaching was most prominent up to bleaches of approximately 80% visual pigment and reached a level approximately 1 log unit beyond that due to loss of quantum catch. At higher bleaches, the effect of loss of quantum catch became more important. Bleaching did not greatly reduce the maximum light-suppressible membrane current. A 99% reduction of the visual pigment permanently reduced the circulating current by only 30%. Visual pigment bleaching speeded up the kinetics of dim flash responses. All electrical effects of bleaching were reversed on exposure to 11-cis retinal, which probably caused visual pigment regeneration. Light adaptation in photopic vision is known to involve significant visual pigment depletion. The present results indicate that cones operate with a maintained circulating current even after a large pigment depletion. It is shown how Weber/Fechner behavior may still be observed in photopic vision when the contributions of bleaching to adaptation are included.
Absorptiometry, Photon↗
A cellular basis for the prolonged QT interval in mammals.
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Aging↗