Direct Intrahepatic Portosystemic Shunt in Budd-Chiari Syndrome: A Case Report and Review of the Literature.

Transjugular intrahepatic portosystemic shunt (TIPS) is an alternative interventional procedure used to manage refractory Budd-Chiari syndrome (BCS) when conservative medical therapy has failed. However, TIPS is not always technically successful because of hepatic vein thrombosis and inability to catheterize the hepatic veins. In these situations, direct intrahepatic portosystemic shunt (DIPS) with access to the portal vein from the IVC has been shown to be a viable alternative that may ameliorate portal hypertension in these patients. Typically, DIPS involves the use of transabdominal ultrasound to target the portal vein. Herein a case in which a 39-year-old female underwent DIPS without the use of ultrasound guidance is presented. Instead, a hepatic venogram generated using collateral circulation was used to opacify and guide access to the portal vein.

Characterization and specificity of lipoprotein binding to term human placental membranes.

The binding characteristics of very-low-density (VLDL), low-density (LDL) and high-density (HDL) lipoprotein fractions to a purified human term placental microvillous membrane preparation were determined. Binding of LDL was saturable with a maximal binding capacity of 270 ng LDL protein per mg of membrane protein. Scatchard analysis revealed the presence of a single population of 3.4 X 10(11) sites per mg of membrane protein and a mean affinity constant of 5.8 X 10(-9) M. Binding of VLDL was also saturable but the maximal capacity was 4.5-times greater than that of LDL. The Scatchard analysis revealed the presence of 2.1 X 10(11) binding sites and an affinity constant nearly one order of magnitude greater than that of LDL. Binding of HDL showed less tendency to saturate. Scatchard analysis showed a similar number of receptor sites to that calculated for VLDL and LDL but the affinity constant for HDL was over 100-fold less than that of VLDL. Self- and cross-inhibition studies of VLDL and LDL binding revealed that VLDL was better at blocking the binding of LDL than was LDL itself. This preferential binding of VLDL suggests that this lipoprotein fraction could be an important source of cholesterol for placental progesterone production.

Liposomal thyroxine: a noninvasive model for transplacental fetal therapy.

Drugs that cross the placenta sparingly are currently given directly to the fetus by invasive procedures. We investigated whether anionic small unilamellar (SUV) liposomes of different lipid compositions enhanced the transfer and uptake of T4 in an in vitro model of perfused human term placenta. T4-encapsulated anionic liposomes were prepared using lecithin (F-SUV) or distearoyl phosphatidylcholine (S-SUV) with cholesterol and dicetylcholine. The size distribution, encapsulation efficiency, and stability were determined in blood-based media. The transfer kinetics of free and liposomally encapsulated T4 were studied in a dually perfused isolated lobule of human term placenta, with creatinine and liposomal carboxyfluorescein as marker substances. Concentrations of T4 and rT3 were measured by RIA. T4 crossed the placenta sparingly (1.9 +/- 0.5%) because it was metabolized to rT3 (9.2 +/- 1.3%). Transplacental transfer of T4 was significantly increased by F-SUV (15.8 +/- 2.1%; P < 0.001) and S-SUV liposomes (7.1 +/- 1.2%; P < 0.001), with a concomitant decrease in fetal rT3 levels (P < 0.001). Placental uptake of F-SUV (13.5 +/- 2.0%; P < 0.001) was greater than that of S-SUV liposomes (6.7 +/- 0.8%; P < 0.001). Our data suggest that anionic liposomes increase transplacental transfer of T4. If confirmed in vivo, liposomes may provide an alternative noninvasive method of drug delivery to the fetus.

Assessment of vitamin B 6 status. Studies on pregnant women and oral contraceptive users.

The vitamin B6 status of 10 pregnant women (third trimester), 9 oral contraceptive agent users, and 12 notnpregnant women (controls) was investigated over a 10-week period by means of the erythrocyte glutamate-oxaloacetate transaminase (E-GOT) activation test and by measurements of whole blood pyridoxal phosphate levels. Blood pyridoxal phosphate levels in oral contraceptive agent users (7.6 plus or minus 1.1 ng/ml) were significantly lower than in the control group (9.6 plus or minus 1.7 mg/ml)indicating a relative vitamin B6 deficiency. Pyridoxal phosphate levels in pregnant women(5.1 plus or minus 1.3ng/ml) were even lower; in fact, no overlap was found in individual mean values between the pregnant and control groups. The E-GOT activation test did not indicate a vitamin deficiency in the pregnant women or in oral contraceptive agent users and the E-GOT activation factor did not correlate with blood pyridoxal phosphate levels unless results obtained after pyridoxine hydrochloride (20 mg/day) administration were included. The E-GOT activation test appears to be a poor indicator of vitamin B6 status, except in pronounced deficiency as it is less responsive to vitamin depletion than blood pyridoxal phosphate levels, and suffers from relatively large variations in individual control values. This may be a result of factors unrelated to vitamin B6 as blood pyridoxal phosphate levels remained fairly constant in the individuals investigated.

A monoclonal antibody based solid-phase enzyme-binding assay to measure levels of placental alkaline phosphatase in serum of women during pregnancy.

Monoclonal antibodies raised against highly purified placental alkaline phosphatase (PALP) reacted specifically with PALP and were found not to cross-react with the liver, kidney and intestinal enzymes. One of these antibodies (AP-3) was selected to develop an enzyme-binding assay to measure levels of PALP in the sera of 11 women throughout pregnancy. PALP activity rose sharply after 28 weeks of gestation reaching a peak at delivery followed by an immediate drop within 4 days to values approaching non-pregnant levels. The potential of using this assay as an index of placental function to monitor progress of a pregnancy is discussed.

Purification and properties of human placental cathepsin D.

Human placental cathepsin D has been purified 6000-fold and its properties characterized. Its molecular weight has been ascertained to be 42 000 by gel filtration and 43 300 by analytical ultracentrifugation. SDS gel electrophoresis in the presence of beta-mercaptoethanol cleaves the enzyme into two polypeptides of molecular weights 28 200 and 14 400. The placental enzyme resembles cathepsin D isolated from other mammalian tissues in many of its properties, including pH optimum. The higher degree of purification has led to a shift in the isoelectric points of the three isoenzymes from those recorded by other authors. Antibodies raised against cathepsin D in rabbits inhibit it at pH 5.0, and the inhibition is almost 100 per cent with adequate concentrations of monospecific antibody.

Identification and estimation of cell types in mixed primary cell cultures of early and term human placenta.

Placental villi of early and term human placentae were dissociated with trypsin and mixed cell cultures were established. The different cell types were identified and estimated over a 14-day culture period using antibodies to keratin and vimentin filaments and their capacity to phagocytose yeast. The three main cell types were found to be epithelial-, macrophage- and fibroblast-like cells. The epithelial-like cells can be further divided into the multinucleated and the small- and medium-sized round cells, and these are most likely to be derived from the trophoblast. The cellular composition of cultures were different for early and term placentae and also varied characteristically over the 14-day cultures period.

Maternal to fetal movement of creatinine as a measure of perfusion efficiency and diffusional transfer in the isolated human placental lobule.

A method employing the maternal to fetal transfer of the slowly diffusing molecule creatinine in the closed-circuit dual perfusion of a term human placental lobule is described. This molecule provides an alternative to the use of antipyrine and is a useful tool in determining the overlap of the two circulations and the available exchange area in this preparation.

Uptake and fate of exogenous immunoglobulin G in the perfused human placenta.

The steady-state transfer of 125I-labelled human or bovine immunoglobulin G from the maternal circulation and its fate during transport to the fetal circulation were studied over a 2 h period in an intact perfused human placental lobule. The 125I activity in the closed-circuit fetal circulation rose linearly throughout this time. The transfer rate, expressed as a percentage of the total activity administered, was 0.11% per hour for human IgG and 0.04% per hour for bovine IgG. 97-99% of the 125I activity in the maternal circulation was associated with high molecular weight protein which was characterised as IgG. The corresponding figure for the fetal side was 10-30%. It is concluded that human IgG is taken up in preference to bovine IgG at the maternal surface of the syncytiotrophoblast but subsequently the majority of the internalised immunoglobulin is broken down intracellularly and the fragments released into the fetal circulation.

Optimization of gray/white matter contrast with fast inversion recovery for myelin suppression: a comparison of fast spin-echo and echo-planar MR imaging sequences.

We compared two MR imaging sequences, fast inversion recovery for myelin suppression (FIRMS) and echo-planar FIRMS (EP-FIRMS), for depicting gray/white matter contrast. In 18 patients, the frequency bandwidth (BW) was optimized for each sequence; in nine patients, the BW was held constant. In the BW-optimized group, the mean contrast-to-noise ratio (C/N) was three times higher with the FIRMS sequence. In the BW-constant group, the mean C/N was 27% higher with the EP-FIRMS sequence; however, geometric distortion degraded the EP-FIRMS images excessively. For optimal gray/white contrast, FIRMS appears to be the superior pulse sequence.

Transfer of heparin across the human perfused placental lobule.

A system of dual perfusion of an isolated lobule of term human placenta was used as a model to study the transfer of heparin from maternal to foetal circulation. The metabolic viability of the system was assessed by measuring beta-HCG and alkaline phosphatase levels in both maternal and foetal perfusates. Creatinine and antipyrine were used as markers to determine juxtaposition of the maternal and foetal circulations. Results of this study indicate that following administration of a single bolus dose of heparin into the maternal circulation, its concentration declined slowly from 99.01 +/- 2.98 at 15 min to 97.23 +/- 4.12% and transfer of heparin in the foetal circulation was linear and increased from 0.10% +/- 0.05% at 15 min to 0.46 +/- 0.19% over a period of 120 min. The maternal (MAUC) and foetal (FAUC) concentration-time integrals were found to be 70160 +/- 1332 and 340 +/- 30 int. units min mL-1, respectively. Placental permeability of heparin and creatinine, calculated as the ratio of foetal concentration to the integral maternal-foetal concentration difference, was 8.65 x 10(-5) +/- 0.80 x 10(-5) and 0.033 +/- 0.006 mL min-1 g-1 of perfused placental weight, respectively. These data suggest that heparin was transferred from the maternal to the foetal circulation in small quantities.

Effect of the size of liposomes on the transfer and uptake of carboxyfluorescein by the perfused human term placenta.

The effect of the size of liposomes on the uptake and transfer of the low molecular-weight, hydrophilic and polar molecule carboxyfluorescein has been determined across the perfused human term placenta. Carboxyfluorescein-encapsulated neutral liposomes of three different sizes were prepared from equimolar concentrations of lecithin and cholesterol. Size distribution, encapsulation efficiency and stability of liposomes in blood-based media were determined. The concentration of carboxyfluorescein was measured spectrophotometrically. The transplacental transfer and placental uptake of free carboxyfluorescein (control data) were respectively 1.9 +/- 0.2 and 5.0 +/- 0.7% of initial dose. The placental uptake and foetal concentration of carboxyfluorescein were significantly increased by small liposomes (P < 0.05), and reduced by large (0.82 +/- 0.13%; P < 0.05) and multilamellar liposomes (0.32 +/- 0.11%). There was a negative correlation between liposome size and transplacental transfer (y = -0.53 + 0.9x; r = 0.96; P < 0.001; n = 24) and placental uptake of carboxyfluorescein (y = -5.9 + 6.5x; r = 0.84; P < 0.001; n = 24). The study indicates that placental uptake and transfer rate of liposomal carboxyfluorescein were dependant upon the size of liposomes.

Differential binding of warfarin to maternal, foetal and non-pregnant sera and its clinical implications.

The object of this study was to determine whether differential binding of sodium warfarin in paired maternal and cord sera accounts for its adverse effects on the foetus. In-vitro binding of sodium warfarin to human serum albumin in maternal, foetal, and non-pregnant (control) subjects was determined by equilibrium dialysis at 37 degrees C. Our data suggest that at therapeutic concentrations, sodium warfarin has a single high affinity binding site on human serum albumin with an association constant of 1.65 x 10(-3) M. Serum albumin concentration in the control sera (4.42 +/- 0.08 g dL-1) was comparable with that in the cord sera (4.54 +/- 0.26 g dL-1) but was significantly higher (P < 0.01) than the maternal levels (4.03 +/- 0.21 g dL-1). Binding data indicate that the fraction of unbound warfarin in the foetal sera (6.8 +/- 1.9 g dL-1) was significantly higher than in the maternal (3.60 +/- 1.3 g dL-1; P < 0.01) and non-pregnant sera (1.96 +/- 0.6 g dL-1; P < 0.001). The maternal and foetal fractions of free warfarin were directly proportional to the concentrations of free fatty acids (y = 1268 - 110x; r = 0.93; P < 0.001), and bilirubin (y = 8.7 + 1.4x; r = 0.91; P < 0.001), respectively. This study indicates that warfarin was more strongly bound in the maternal sera than in the foetal sera; this was probably because of the competitive and allosteric effect of free fatty acid and bilirubin in the maternal and foetal sera, respectively. The clinical significance of this observation is discussed in this paper.