This study investigated the effects of a range of pharmaceutical drugs with ion channel-blocking activity on the heart of gestation day 13 rat embryos in vitro. The general hypothesis was that the blockade of the I(Kr)/hERG channel, that is highly important for the normal functioning of the embryonic rat heart, would cause bradycardia and arrhythmia. Concomitant blockade of other channels was expected to modify the effects of hERG blockade. Fourteen drugs with varying degrees of specificity and affinity toward potassium, sodium, and calcium channels were tested over a range of concentrations. The rat embryos were maintained for 2 hr in culture, 1 hr to acclimatize, and 1 hr to test the effect of the drug. All the drugs caused a concentration-dependent bradycardia except nifedipine, which primarily caused a negative inotropic effect eventually stopping the heart. A number of drugs induced arrhythmias and these appeared to be related to either sodium channel blockade, which resulted in a double atrial beat for each ventricular beat, or I(Kr)/hERG blockade, which caused irregular atrial and ventricular beats. However, it is difficult to make a precise prediction of the effect of a drug on the embryonic heart just by looking at the polypharmacological action on ion channels. The results indicate that the use of the tested drugs during pregnancy could potentially damage the embryo by causing periods of hypoxia. In general, the effects on the embryonic heart were only seen at concentrations greater than those likely to occur with normal therapeutic dosing.

Drugs that induce periods of bradycardia and/or arrhythmia of the embryonic heart and cause the embryo to become hypoxic are potential human teratogens.

This study investigated the effects of a range of antidepressant drugs on the heart of gestation day 13 rat embryos in vitro. The general hypothesis was that the drugs would adversely affect the function of the embryonic heart since they all have some cardiac ion channel blocking activity in addition to their main pharmacological effect on neurotransmitters. The results showed that all the tested drugs caused bradycardia in a generally concentration-dependent manner. At higher concentrations most of the drugs caused some degree of heart block consistent with sodium channel blockade and some drugs also showed negative inotropy associated with blockade of the L-type calcium channel. One drug, trazodone, caused arrhythmia consistent with blockade of the hERG (human ether-a-go-go related gene) potassium channel. In general the effects on the embryonic rat heart were only seen at "free drug" concentrations much greater than those likely to occur in pregnant women taking antidepressant medication. The least margin of safety was seen with the tricyclic antidepressants and the serotonin antagonist and reuptake inhibitor trazodone.

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Hematopoietic stem cells (HSCs) are multipotent, self-renewing cells that can differentiate into myeloid or lymphoid cells. The mobilization and differentiation processes are affected by the external environment, such as extracellular matrix and soluble molecules in the niche, where the lipid rafts (LRs) of the HSCs act as the receptors and control platforms for these effectors. LRs are membrane microdomains that are enriched in cholesterol, sphingolipid, and proteins. They are involved in diverse cellular processes including morphogenesis, cytokinesis, signaling, endocytic events, and response to the environment. They are also involved in different types of diseases, such as cancer, Alzheimer’s, and prion disease. LR clustering and disruption contribute directly to the differentiation, homing, hibernation, or mobilization of HSCs. Thus, characterization of LR integrity may provide a promising approach to controlling the fate of stem cells for clinical applications. In this review, we show the critical role of LR modification (clustering, disruption, protein incorporation, and signal responding) in deciding the fate of HSCs, under the effect of soluble cytokines such as stem cell factor (SCF), transforming growth factor- β (TGF-β), hematopoietic-specific phospholipase Cβ2 (PLC-β2), and granulocyte colony-stimulating factor (G-CSF).

Tamoxifen (TAM) is a hormonal drug and is mainly used as an anti-estrogen in breast cancer patients. TAM binds to estrogen receptors (ERs), resulting in inhibition of estrogen signaling pathways and thus, a downregulation of cell proliferation. Cancer cells with negative or low ER expression will not uptake TAM and will show low response. Poly (methyl methacrylate) (PMMA) nanoparticles were prepared using surfactant-free emulsion polymerization, then were loaded with Nile red (NR), which resulted in PMMA-NR. To enhance TAM delivery to cervical cancer cells (HELA), which is considered ER-negative, we loaded TAM and polymethyl methacrylate nanoparticles-Nile-red into silica (PMMA-NR-Si-TAM). The uptake and intracellular distribution were visualized by confocal laser scanning microscopy, and the in vitro cytotoxic activity was evaluated by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay using HELA and non-tumorigenic cell line HFF-1. The sensitivity of HELA (LC50: 207.31 µg/mL) and HFF-1 (LC50: 234.08 µg/mL) to free TAM was very low. However, after the encapsulation of TAM with PMMA-NR, the sensitivity significantly increased HELA (LC50: 71.83 µg/mL) and HFF-1 (LC50: 37.36 µg/mL). This indicates that TAM can be used for the treatment of ER-negative cervical cancer once conjugated to PMMA-NR nanoparticles. In addition, the PMMA-NR formulation appears to be highly suitable for cancer imaging and drug delivery.

Objective Phenytoin exposure during the first trimester of pregnancy increases the risk of maxillary hypoplasia and cleft lip. The etiology of phenytoin embryopathy is unknown. Interestingly, phenytoin is also known to induce hyperglycemia in humans as well as rats. This study uses a rat model of fetal phenytoin syndrome to examine the role of hyperoxia, hyperglycemia, and arachidonic acid deficiency in the development of cleft lip and maxillary hypoplasia. Methods Pregnant rats were dosed with phenytoin during the critical period of lip development (day 11 of pregnancy) with or without supplemental oxygen, insulin, or arachidonic acid. The fetuses from all studies were examined at term. Results The frequency of cleft lip and maxillary hypoplasia was reduced by treating dams at the time of phenytoin exposure with either increased oxygen or insulin. However, in fetuses from phenytoin‐treated dams dosed with arachidonic acid, the incidence of severe lip deformities remained the same although there was an increase in normal and mildly affected fetuses. Interestingly, this occurred in embryos from hyperglycemic dams. Significance Together, the results from these experiments suggest phenytoin‐induced malformations may be a multifactorial process as malformations were not solely linked to a hyperglycemic state of the dam.

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