Standard heparin, an effective treatment for antepartum thromboembolic disease, is thought to be safe for the fetus since it does not cross the placenta. Recently, a number of low molecular weight heparins have been prepared which have been shown to produce less bleeding than standard heparin for an equivalent antithrombotic effect in experimental animals. These observations suggest that the low molecular weight heparins may also provide superior antithrombotic therapy in antepartum thromboembolic disease. However, it is not known whether the low molecular weight heparins cross the placenta. To determine this, we examined the pharmacokinetics of 125I-labelled standard heparin and a low molecular weight heparin, and their anticoagulant effects in mother and fetus, using a pregnant sheep model. Catheters were inserted into maternal and fetal femoral arteries at 108-119 d gestation (term: 147 d). 1-3 days later the mothers were given a bolus i.v. injection of 5000 anti-Xa units of 125I-labelled standard heparin or low molecular weight heparin, CY 222. Nine serial blood samples were collected over 4 h from both mother and fetus for measurements of radioactivity, anti-Xa activity (chromogenic) and activated partial thromboplastin times. When therapeutic levels of standard and CY 222 heparins were achieved in the mother, there was no detectable radioactivity or anticoagulant effect in the fetus. We conclude that standard heparin and the low molecular weight CY 222 do not cross the placenta in the pregnant sheep.
To reduce the melt flow index of HDPE granules, you can increase the molecular weight of the polymer by using a higher molecular weight grade of HDPE, incorporating chain extenders or cross-linking agents, or blending with a lower molecular weight polymer. These methods can help decrease the flowability of the material, resulting in a lower melt flow index.
Polymers do not have a uniform or fixed molecular weight due to their inherent nature of being composed of long chains of repeating units, or monomers, which can vary in length. During the polymerization process, the reaction conditions and the presence of different types of monomers lead to the formation of chains of varying lengths, resulting in a distribution of molecular weights. Additionally, factors such as branching, cross-linking, and incomplete reactions contribute to this variability, making it difficult to achieve a single, uniform molecular weight in a polymer sample.
Get the MR of the NaH2PO4 molecule. Now use the 1M = (MR)g/L to work out the equation. The last equation you need is 20mM = (X)g/L Now you make the units the same, cross multiply and get your answer for X. Once you do this a few times it becomes second nature.
Molecular size can influence how a drug is absorbed, distributed, metabolized, and excreted in the body. Smaller molecules may be more easily absorbed but can have a shorter duration of action, while larger molecules may have slower absorption but longer-lasting effects. Additionally, molecular size can impact the drug's ability to cross cell membranes and interact with target molecules.
IgG is the most abundant type of immunoglobulin in the blood, making up about 75% of all immunoglobulins. It plays a key role in immune response by helping to neutralize pathogens and toxins, and is the only antibody class that can cross the placenta from mother to fetus.
No.
its structure whether its linear or cross linked its molecular weight
vitamin a,vitamin d,usually cross placenta during pregnancy.exept vitamin c
yes
To reduce the melt flow index of HDPE granules, you can increase the molecular weight of the polymer by using a higher molecular weight grade of HDPE, incorporating chain extenders or cross-linking agents, or blending with a lower molecular weight polymer. These methods can help decrease the flowability of the material, resulting in a lower melt flow index.
IgG is the only antibody small enough to cross he placenta.
IgG is an immunoglobluin monomer, meaning that it is one immunoglobulin that is small enough to cross the placenta. An example would be the Rh antibody that causes isoimmunization between Rh negative mothers and Rh positive fetuses. In constrast, ABO blood group immunoglobulins are IgM which is a pentamer, meaning it is composed of 5 immunoglobulins and is too large to cross the placenta.
semen does not cross into the placenta and has no effect on baby in womb.
No. Red blood cells do not cross the placenta.
This is called natural passive immunity.
babies may be born with a drug dependency
The embryo gets all the oxygen, and all the nutrients that it needs from the mother's blood supply, all of which crosses the placenta, through the umbilical cord into the embryonic blood system.