How much do 'attention' tests tell us?

Twelve measures commonly used to assess attentional processes were examined in a sample of 120 outpatients referred for neuropsychological evaluation. A single factor solution emerged. A second analysis partially replicated factors derived by Shum. McFarland, Bain, and Humphreys (1990). Classification rates (impaired vs. unimpaired) for the measures are presented. The implications of these findings for clinical assessment of attention are discussed     

Pharmacokinetics of isometronidazole. Basic model and estimation of the kinetic parameters from experimental data.

For the optimal timing of application of radiosensitizers in a course of radiotherapy it is important to know the sensitizer concentration at the time of irradiation. We have studied the pharmacokinetics of the hypoxic cell sensitizer isometronidazole in man and mouse and analyzed the data on the basis of an open two-compartment model after extravasal application. The parameter estimation is performed directly to avoid estimation biasing and data points from blood and tissue compartments are approximated simultaneously. The values obtained differ significantly from the estimations calculated by other authors for the same data.     

Visualization of 3-D treatment plans with fast neutrons.

The treatment planning for radiotherapy with fast neutrons requires modifications of the planning systems used for photons. The neutron- and photon-component of the treatment fields must be determined and can then be used for separate calculations. The corrections for inhomogeneities are performed by use of attenuation coefficients and the corresponding corrections for changes in the kerma. The treatment planning system MEVAPLAN (Siemens) was modified to follow these requirements. Thus treatment planning for 14 MeV DT-neutrons could be performed. The multiplanar option is used to calculate 3D-dose distributions based on up to 40 serial CT slices. The generated three-dimensional dose matrix and the CT data are transferred via magnetic tape to the visualization system VOXEL-MAN developed at the University Hospital of Hamburg. This system uses a ray casting algorithm based on the generalized Voxel-model to display detailed 3D-images of human anatomy together with the calculated dose distribution. Different treatment plans for neutrons and photons are calculated and visualized. Various manipulations of the data-sets are displayed to improve the critical examination of the simulated dose distribution and to discern the quality of treatment techniques.     

Intra-articular injections and articular cartilage metabolism

Summary We studied the effects of repeated intra-articular injections of sterile 140 mM NaCl solution on articular cartilage in adult rabbits. After 20 injections into the knee joints over a period of 4 weeks, chondrocyte glucosaminoglycan synthesis was evenly reduced in all cartilage layers, accompanied by a significant proteoglycan depletion of the matrix which was most marked in the superficial half of the cartilage. These and other changes only partially reversed during a further 4-week period after the injections had been stopped. Our data underline the need for a clear-cut indication for intra-articular injections. The microtrauma caused by injection, in conjunction with the introduction of a carrier solution into the joint, may, at least when repeated at short intervals, lead to measurable damage to the articular cartilage.Recipient of grant no. Ne 308/1-1 from the Deutsche Forschungsgemeinschaft, Bonn, Germany     

Endogenous and recombinant erythropoietin levels decline in human amniotic fluid and fetal plasma in vitro at 37 degrees C.

OBJECTIVE: To determine the in vitro stability of endogenous and recombinant erythropoietin (EPO) incubated at 37 degrees C in amniotic fluid (AF) and fetal plasma. STUDY DESIGN: Endogenous and recombinant EPO in AF, fetal plasma and phosphate buffer were incubated in vitro for 21 days at 37 degrees C. Serial aliquots were analyzed for EPO and the rates of EPO decline were compared within and between groups. RESULTS: Endogenous and recombinant EPO declined significantly in plasma and AF at 37 degrees C. Endogenous EPO displayed a similar linear rate of decline in AF and plasma, with nearly 70% of the initial hormone concentration remaining at 21 days. Recombinant EPO incubated in buffer did not change. CONCLUSIONS: Using the rate of decline in endogenous EPO we observed, EPO levels measured in AF or plasma within 21 days of fetal demise can be extrapolated back to the level likely present at fetal death.     

Plasma Concentrations of Mycophenolic Acid Acyl Glucuronide Are Not Associated with Diarrhea in Renal Transplant Recipients

The aim of this study was to determine whether plasma concentrations of the acyl (AcMPAG) and phenolic (MPAG) glucuronide metabolites of mycophenolic acid (MPA) were related to diarrhoea in renal transplant patients on mycophenolate mofetil (MMF) with cyclosporine (CsA) or tacrolimus (TCL). Blood samples (0, 30, 120 min) were taken at days 3, 10, week 4, months 3, 6 and 12 for determination of MPA, MPAG and AcMPAG. MPA-AUC was estimated using validated algorithms. Two hour AUCs were calculated for MPAG and AcMPAG. Immunosuppressive therapy consisted of CsA/MMF (n= 110) and of TCL/MMF (n= 180). In 70/290 (24%) patients 86 episodes of diarrhoea were recorded during 12 months. Significantly more patients on TCL (31.1%) suffered from diarrhea compared to CsA (12.7%). MMF dose, MPA-AUC and the 2 h AUCs of MPAG and AcMPAG did not differ between patients with and without diarrhoea. Plasma AcMPAG and MPAG concentrations were substantially higher in patients on CsA compared with TCL, while MPA-AUC was lower in the former group. These data support the concept that CsA inhibits the biliary excretion of MPAG and AcMPAG, thereby potentially reducing the risk of intestinal injury through enterohepatic recycling of MPA and its metabolites.     

A questionable parasitic macular cyst

A 60 year old male patient is introduced who developed a loss of vision caused by chorioretinal cystic alteration in the macula of the left eye 9 months after a routine extracapsular cataract surgery with implantation of posterior chamber lens. There existed no other general symptoms, hematologic values and serology were regular. Having discussed literature the diagnosis of solitary Toxocara canis granuloma was produced.