Stochastic morphometric model of the BALB/c mouse lung.

The laboratory mouse is often used as a human surrogate in aerosol inhalation studies. Morphometric data on the tracheobronchial geometry of three in situ lung casts of the Balb/c mouse lung produced by the Air Pollution Health Effects Laboratory were analyzed in terms of probability density functions and correlations among the different airway parameters. The results of this statistical analysis reveal significant differences in diameters and branching angles between major and minor progeny branching off from the same parent airway at a given airway bifurcation. Number of bronchial airways generations along a given path, expressed by the termination probability, branching angles, and daughter-to-parent diameter ratios indicate that the location of an airway with defined linear airway dimensions within the lung is more appropriately identified by its diameter (or its parent diameter) than by an assigned generation number. We, therefore, recommend classifying the mouse lung airways by their diameters and not by generation numbers, consistent with our previous analysis of the rather monopodial structure of the rat lung (Koblinger et al., J Aerosol Med 1995;8:7­19; Koblinger and Hofmann, J Aerosol Med 1995;8:21­32). Because of lack of corresponding information on respiratory airways, a partly stochastic symmetric acinar airway model was attached to the tracheobronchial model, in which the number of acinar airways along a given path was randomly selected from a measured acinar volume distribution. The computed distributions of the geometric airway parameters and their correlations will be used for random pathway selection of inhaled particles in subsequent Monte Carlo deposition calculations.

Three-dimensional assessment of the morphology of the umbilical artery in normal and pre-eclamptic placentas.

AIM: Pre-eclampsia is one of the main causes of intrauterine growth retardation. Although there are many studies performed in this setting showing the course of the umbilical vessels within the umbilical cord along with its structural changes, studies are lacking with regard to intraplacental vasculature and its structural changes. METHODS: We investigated whether the vascular pattern differed in preeclamptic placentas in terms of intraplacental course and morphometry of the umbilical artery by using vascular corrosion cast technique. Furthermore, cross-sections taken from umbilical artery branches at different levels within the placenta, were examined with both light and scanning electron microscopy (SEM). RESULTS: Vascular corrosion casts generated in both pregnancy groups should be defined with the main umbilical artery divided into 2-4 primary branches. No significant difference was seen between normal and pre-eclamptic groups regarding the diameters of primary and secondary branches and the number of cotyledons contained (P > 0.05). However, microscopic studies demonstrated expanded intervillous spaces in the placentas of pre-eclamptic pregnancies. Under SEM, distortion on the endothelial surface of the umbilical artery and an increase in vessel diameter and wall thickness have been determined in pre-eclamptic placentas. Furthermore, the branching pattern and changes affecting the endothelial surface of the umbilical artery have been shown three-dimensionally in pre-eclamptic placentas, using corrosion cast technique and SEM, respectively. CONCLUSION: While microscopic findings were consistent with the Doppler ultrasonography findings, namely higher systole/diastole ratio and increased resistance (RI) and pulsatile (PI) index in the umbilical artery, no clear morphometric change has been observed.

The significance of aductal zones on pancreatograms: an anatomo-clinical assessment.

The authors analyzed 177 endoscopic retrograde pancreatograms (ERPs) with normal findings. The complete visualization of the side branches was achieved in 128 patients (72.3%), and aductal zones in the isthmus and mid-body of the pancreas were noted in 49 (27.3%) of these patients. The existence and incidence of the aductal zones were evaluated and verified in 141 anatomical duodenopancreas specimens. Thirty-two corrosion casts and 109 postmortem pancreatograms were analyzed. The postmortem specimens had a 36.2% incidence of aductal zones in the same location, with no statistically significant difference compared with the clinical pancreatograms. The visualization of the side branches was 100% on the postmortem pancreatograms, indicating that the clinical ERCP incidence of aductal zones is realistic.