Photoradiation of perfused placental tissue--a suitable in vitro model for photodynamic therapy?

Our aim was to evaluate the isolated placental lobule as a model to study the cytotoxic effects of photodynamic therapy (PDT) in vitro. Ten human placental lobules were dually perfused with a modified medium 199 for a 4-hour period. Photosan III was added to the fetal perfusate at a dose of 5 mg/kg tissue, and laser light (630 nm wavelength) provided by an argon-pumped dye laser was applied at 50 J/cm2 in the experimental group (n=5). Potassium and lactate dehydrogenase (LDH) release into the perfusate as well as the transplacental creatinine passage from PDT-treated placentas and control placentas (n=5) were compared, and light microscopic examinations of the placental tissue were performed after the experiments. Potassium release into the fetal perfusate was higher in the PDT-treated placental lobules (p<0.05), and weight gain during the artificial perfusion suggests the development of edema only in the photoradiated lobules (p<0.01). The release of the bigger molecules of the LDH however was comparable in the two experimental groups, and transplacental creatinine passage was not affected by photoradiation. Light microscopic examinations demonstrated lesions at the cytotrophoblast, the syncytiotrophoblast and the endothelium of the fetal vessels of the photoradiated placentas, although they were not specific and could also be found in the control tissue. We conclude that the isolated placenta may be used to study cytotoxic effects of photoradiation in vitro, but better specifity and sensitivity might be achieved if a. The perfusion time is prolonged to make the difference between the experimental and the control group clearer and b. Electron microscopic investigations are made to demonstrate intracellular lesions of the mitochondria and the endoplasmic reticulum.

[Fetomaternal macrotransfusion after attempted external version]

BACKGROUND

External cephalic version is an alternative to both vaginal breech delivery and to caesarean section. The objective of this study was to summarize potential complications of external cephalic version. Which means are available for early detection and treatment of these complications?

CASE REPORT

A 28-year-old 1/0 with breech presentation was considered for external cephalic version at the 38th week of gestation. As three version attempts failed, the patient was discharged after normal fetal heart tone (FHT) registration and normal ultrasonographic findings on the next day. Caesarean section was planned six days later. On the day of admission, FHT registration revealed a decreased beat-to-beat variability and a sinusoidal baseline. Doppler-flow indices of the A. umbilicalis and A. cerebri media were normal, although middle cerebral artery peak systolic velocity was increased. Rapid caesarean section was performed, and an anemic baby (hemoglobin 3.4 g/dl) was born. After transfusion of 100 ml red blood cells, further development of the newborn was normal.

DISCUSSION AND CONCLUSION

Fetomaternal macrotransfusion may be a rare complication of external cephalic version, occurring even several days after the mechanical manipulation. FHT registrations and ultrasonographic doppler flow measurements performed periodically unit birth are necessary to detect such complications early. The Kleihauer-Betke test is the method of choice to diagnose fetomaternal macrotransfusion.

[Concepts of quality assurance in obstetrics and gynecology]

The safeguarding of quality has reached an essential position in medical area. The creation of corresponding concepts with definition of tasks for quality assessment is one of the most important challenges for public health organizations and politicians. The still established projects in gynecology and obstetrics in Germany now carried out that the conscience for the necessity of quality safeguarding is in high gear.A summary of the quality safeguarding projects and tools is given.

[Publishing guidelines on the internet]

Guidelines are well established in modern medicine as a tool of quality assurance. New developments in Information Technology (IT) alters strategies in communication, and influences the publication of important notes or research findings. Acceptance and efficiency of guidelines depends on promptness of publication. Using the internet to publish guidelines does not only improve success of transferal but also changes interaction between physicians and patients.

Diabetes mellitus and islet cell specific autoimmunity as adverse effects of immunsuppressive therapy by FK506/tacrolimus

The induction of diabetes has been recognised as adverse effect of the immunsuppressive drug FK506/Tacrolimus. The aim of this study was to clarify whether insulinopenia or insulin resistance dominates and whether islet cell autoantibodies are present in patients treated by FK506. We investigated 58 patients 1-3 years after liver transplantation while under therapy with FK506 or CsA and prednisolone (0-7.5 mg) for basal blood glucose levels and islet-cell specific autoantibodies. A subgroup of 20 patients on FK506, 10 patients on cyclosporin and 15 healthy volunteers were metabolically tested by oGTT. Five patients had diabetes pre-transplantation. After transplantation, 9/28 FK506-treated patients developed newly diagnosed diabetes compared to 0/25 cyclosporin-treated patients (p<0.01). Both patient groups showed significantly higher fasting blood glucose, insulin or C-peptide levels compared to controls. Through the oGTT, FK506-treated patients without diabetes, but not cyclosporin-treated patients, had higher C-peptide levels compared to controls (p<0.05). Five/32 patients on FK506 compared to 0/26 patients on cyclosporin (p<0.05) had islet cell specific autoantibodies, mainly ICA without GAD- or IA2-Ab, a feature described for latent autoimmune diabetes in adults. ICA positivity was correlated to the diabetes associated HLA haplotype DR4/DQ*0302 (p<0.05). Although the interpretation of our metabolic data in patients with concomitant liver disease and prednisolone therapy has limitations, we suggest insulin resistance caused by treatment with FK506. However, manifestation of diabetes was associated with relative insulinopenia rather than insulin resistance in patients on FK506. Immunsuppressive therapy by FK506 was not able to suppress islet cell autoimmunity, and may even induce it in genetically predisposed patients.

Digoxin, flecainide, and amiodarone transfer across the placenta and the effects of an elevated umbilical venous pressure on the transfer rate

Clinical observations suggest that flecainide might pass the placenta more easily than digoxin, and that its transfer is less disturbed in case of hydrops fetalis than that of digoxin. The purpose of the study was to compare the materno-fetal transplacental transfer of digoxin, flecainide, and amiodarone, another antiarrhythmic agent used in the treatment of fetal tachyarrhythmia, and to assess the effect of an elevated umbilical venous pressure (UVP) on the transfer rate. Isolated lobules of 16 human placentas were dually perfused after spontaneous delivery or caesarean section. The transplacental transfer (area under the curve in the maternal compartment [maternal AUC], area under the curve in the fetal compartment [fetal AUC], kinetic parameters) of digoxin, flecainide, and amiodarone was calculated after these drugs were added to the maternal circuit. In five experiments, the effect of increased UVP on the transplacental transfer rate was assessed by elevating the UVP by 10 cm H2O. Flecainide efflux out of the maternal compartment was significantly greater than that of digoxin (maternal AUC 57.4% +/- 5.1 %/min vs 73.9% +/- 1.5%/min), whereas the flecainide influx into the fetal circulation was smaller (fetal AUC 9.3% +/- 4.1%/min vs 11.5% +/- 2.0%/min). Only in 50% of the experiments were the smallest amounts of amiodarone detectable in the fetal compartment. An elevation of the UVP reduced the influx of digoxin and flecainide into the fetal compartment (fetal AUC) from 11.5% +/- 2.0%/min to 7.4% +/- 1.9%/min and from 9.3% +/- 4.1% to 4.7% +/- 1.4%/min, respectively. Materno-fetal transplacental transfer of digoxin, flecainide, and amiodarone decreases in this sequence. Fetal cardiac insufficiency accompanied by an elevation of the UVP might reduce the transplacental transfer of these drugs, although no significant difference could be found between the reduction of transfer of digoxin and flecainide.

Extracorporeal perfusion of the human uterus as an experimental model in gynaecology and reproductive medicine

Experimental perfusion of various organs has primarily been used in transplantation medicine to study the physiology, pathophysiology and metabolism of tissues and cells. The purpose of this study was to establish an experimental model for the extracorporeal perfusion of the human uterus with recirculation of a modified, oxygenated Krebs-Henselait solution, in comparison with a non-recirculating perfusion system. With consent of the patients we obtained 25 uteri after standard hysterectomy. We performed an isovolumetric exchange of the perfusion medium at different intervals from 1 to 6 h and examined pH, pO(2), pCO(2), lactate, lactate dehydrogenase and creatine kinase by taking arterial and venous samples every hour for 24 h. We found the perfusions to be adequate when maintaining flow rates at 15-35 ml/min and at pressures ranging from 70 to 130 mmHg. Isovolumetric exchange of the perfusate every 3-4 h was the maximum interval to keep pH, the arterio-venous gradients of pO(2) and pCO(2), and the other biochemical parameters in physiological ranges. Examination by light and electron microscopy showed well-preserved features of myometrial and endometrial tissue. However, a 6 h exchanging interval led to increasing hypoxic and cytolytic parameters during the whole perfusion period. X-ray studies using digital subtraction angiography and perfusion studies with methylene blue demonstrated the homogeneous distribution of the perfusion fluid throughout the entire organ.

Simulation of herbicide degradation in different soils by use of Pedo-transfer functions (PTF) and non-linear kinetics

The degradation behaviour of bentazone in 14 different soils was examined at constant temperature and moisture conditions. Two soils were examined at different temperatures. On the basis of these data the influence of soil properties and temperature on degradation was assessed and modelled. Pedo-transfer functions (PTF) in combination with a linear and a non-linear model were found suitable to describe the bentazone degradation in the laboratory as related to soil properties. The linear PTF can be combined with a rate related to the temperature to account for both soil property and temperature influence at the same time.

[TNF-alpha secretion by peritoneal macrophages in endometriosis]

Beside of other cytokines and growth-factors Tumor Necrosis Factor Alpha (TNF-alpha) exerts as a macrophage-derived cytotoxic product a variety of immunologic effects in the human organism. It is also an important angiogenetic factor and regarding its cytotoxicity toward gametes TNF-alpha plays an essential role as pelvine mediator of sterility. The purpose of our study was to evaluate the TNF-alpha-synthesis of Peritoneal-Macrophages (PM) in patients with and without endometriosis and to determine if a correlation exists between TNF-alpha-synthesis and various degrees of the activity of endometriosis. For reasons of sterility 40 women underwent diagnostic laparoscopy and were staged according to the rAFS-classification as well as the macroscopic aspect of activity into a control group with endometriosis-free pelvic situs (n = 14) and three subgroups characterized by the increasing stage of the disease (n = 26). The TNF-alpha-concentrations (median) in the control group were 3.3 pg/ml, in group 2 with stage I/II rAFS and only low active endometriosis 60.2 pg/ml, in group 3 with stage I/II rAFS but high active endometriosis 83.2 pg/ml and in group 3 with stage III/IV rAFS 168 pg/ml. These data were statistically high significant and showed good conformity with the histological findings. We found significant higher TNF-alpha-concentrations in the peritoneal fluid of patients with endometriosis than in the peritoneal fluid of healthy women. There is a correlation between TNF-alpha-concentrations and the degree of disease.

[Laparoscopic implantation of catheters for continuous ambulatory peritoneal dialysis]

Continuous ambulatory peritoneal dialysis (CAPD) has become an established procedure and is an equal alternative to haemodialysis (HD) in the management of terminal renal failure. Nevertheless CAPD still plays a minor role compared with HD (10% of all dialyses). CAPD offers advantages in quality of live but is still associated with a significant number of complications. The improvement of surgical technique and development of new peritoneal dialysis catheters (PDK) improved the results of peritoneal dialysis. 3 methods for implantation of PDK are used: the open surgical technique, the blind percutaneous procedure and the laparoscopic method. The latter technique is currently an accepted practice. 10 patients were treated by the laparoscopic method. Additionally to the PDK-tunnel of the abdominal wall we used 2 trocars (1 x 5 mm, 1 x 12 mm). Advantages of this technique are avoiding of perforating lesions, possibility for further operations and a safe implantation of the PDK. Peritoneal dialysis was started 7 days after operation with initially low dialysate volumes. The observed incidence of complications and removed catheters are comparable to the reports in the literature.

[Modification of transplacental digoxin transfer in the isolated placental lobule]

Digoxin is widely used in the transplacental therapy of fetal tachyarrhythmia. Unfortunately, in cases with severe cardiac insufficiency and hydrops fetalis, transplacental passage of digoxin is often hampered and therapy therefore ineffective. The present study was designed to establish the isolated placental lobule to quantify transplacental digoxin passage under different experimental conditions. Ten human placentas were obtained immediately after delivery, and a lobule was dually perfused after cannulating a small artery and vein of the chorionic plate and piercing four catheters through the corresponding basal plate. Flow rates were 12 ml/min in the maternal circuit and 6 (I) respectively 3 ml/min (II) in the fetal circuit. The maternal circuit was spiked with digoxin to 6.18 +/- 0.40 ng/ml, and transplacental passage was calculated from repeated fetal and maternal perfusate samples (Fluorescence-Polarization-Immunoassay; TDx, Abbott Laboratories). Within three hours of recirculating perfusion with a fetal flow rate of 6 ml/min (I), digoxin concentrations in the maternal circuit (400 ml) declined to 3.56 +/- 0.09 ng/ml, whereas digoxin levels in the fetal compartment (200 ml) increased to 2.58 +/- 0.37 ng/ml. With a fetal perfusion rate of 3 ml/min (II), the efflux of digoxin out of the maternal circuit was lower (p < 0.05) and the influx in the total compartment was reduced (fetal digoxin concentrations reached only 26.9 +/- 10.6% vs. 39.1 +/- 5.5% of the initial maternal digoxin concentrations). These data suggest that severe fetal cardiac insufficiency with reduced placental perfusion may be in part responsible for the decrease of transplacental digoxin passage in fetuses with hydrops.

Partitioning of chemically modified low-density lipoprotein in aqueous polymer two-phase systems

Aqueous polyethylene glycol (PEG)-dextran two-phase systems containing 10 mM Tris.HCl (pH 7.4) were used for the partitioning of chemically modified low-density lipoprotein (LDL). Anionic modification connected with an increase in the negative surface charge of lipoproteins favours the accumulation of modified LDL in the top phase. The partition coefficient increases depending on the extent of modification. Cationic modification yields lower values for the partition coefficient. Positively charged LDL favours a bottom-phase accumulation. With weakly charged and nearly neutral particles, the Van der Waals interaction between polymer and particle preponderates over electrostatic interactions, leading to a favoured accumulation of LDL in the PEG-rich top phase. Results of measurements of the relative electrophoretic mobility and the determination of free amino groups are in agreement with the calculated values of the partition coefficient. Because the partitioning of LDL is accompanied by aggregation at the interface, experimental techniques have to be carefully standardized. Subtle differences in the surface properties of modified LDL can be detected.

Future research directions and data requirements for developing ambient ozone guidelines or standards for agroecosystems

The ambient air quality in Central Europe appears to have the potential to adversely affect the productivity of the agroecosystems in that geographic area. Therefore, there is a need to develop, validate, and apply air pollutant exposure-plant response models to explain the relationships between the stochastic chemical climate and ecosystem responses. Such models will have to include numerical terms for the effective air pollutant exposure regime to account for the fluxes of matter, energy and information within the ecosystem and its components. The structure and function of the ecosystem which are influenced by the air pollutant flux can be described by a combination of empirical and mechanistic models. A discussion of such an approach is presented in this paper.

[Residues of active substances after consumption of contaminated food: status report on the evaluation of residues with examples of two drugs]

Pharmacokinetic models are presented for the computation of time courses of blood levels of drugs in man following the consumption of contaminated food. Mathematically, two linear systems of differential equations are set up for the donor organism (e.g., trout) and for the recipient, (e.g., man), where the first system generates the initial conditions for the second. Models of this kind are applied to the transfer of chloramphenicol to man via carp and trout (which had previously been administered this drug) and to the transfer of theophylline to infants via breast milk. Limiting concentration profiles are computed by constructing the most favourable and most adverse combinations of parameters with respect to drug elimination in both the donor and recipient organism.