Don R. Hilbelink

Virtual Determination of Sex: Metric and Nonmetric Traits of the Adult Pelvis from 3D Computed Tomography Models

Abstract:  Examination of the adult os coxae and sacrum is one of the most common methods of sex estimation from bone. Medical imaging, such as computed tomography (CT), provides the opportunity for three‐dimensional (3D) imaging of the skeleton from clinical scans of known individuals in situ. In this study, a randomly selected subset of abdominopelvic CT‐derived models were used to evaluate simple, repeatable metric methods of sex estimation based on a combination of obstetric measurements and the traditionally nonmetric Phenice‐derived traits. A four‐variable discriminant function for sex estimation was developed based on statistical analyses. Overall, the cross‐validated accuracy of this method was 100%, with inter‐observer error showing an average of only 2.2%. Comparative analysis was run on the data set using FORDISC 3.0. This study shows that current sex determination standards from the pelvis should be updated to include more in vivo data to increase the accuracy of identification.

Carpal orientation from computed reference axes

Carpal instability is usually diagnosed by abnormal two-plane radiographic angles. These angles are often unreliable. A method that eliminates interpretation of overlapping shadows and uses all of the carpal geometry should improve clinical diagnoses. The digital data from computed tomography scans can be manipulated to describe the carpal orientation in the normal wrist. The digital data from the computed tomography scans of twenty-two normal wrists were used to compute distances with and without directions between the volumetric centroids of the carpal bones. An expansion technique also extracted from the computed tomography data an orthogonal set of vectors, the principal axes. The first principal axis describes the longest dimension of each bone. The average angle produced by the first principal axes of the scaphoid and lunate was 23.6 degrees, scaphoid and capitate was 73.2 degrees, and the capitate and the lunate was 93.5 degrees. These computations represent new carpal axes and intercarpal angles that are not related to the commonly measured two-plane radiographic angles. They should prove helpful in the study of kinematics and pathomechanics in the wrist joint.

Teratogeneic effects of endotoxin on the golden hamster

Gram-negative urinary tract infections in pregnant women have been implicated as causes of maternal endotoxemia and a subsequent higher incidence of malformations in their offspring. A study was performed to evaluate the effects of endotoxin on the development of the golden hamster. Endotoxin was shown to be extremely embryolethal at higher doses and to produce several malformations at lower doses. The pregnant hamster and its developing embryos were observed to be far more sensitive to endotoxin than species examined by other investigators.

Lipoxygenase Activity in Rat Embryos and Its Potential for Xenobiotic Oxidation

This paper reports dioxygenase activity in rat embryos and demonstrates for the first time the ability of rat embryo lipoxygenase (LO) to oxidize xenobiotics in vitro. Significant dioxygenase activity towards linoleic acid was found in cytosol isolated from rat embryos in different developmental stages on day 9 and 10 of gestation. All four xenobiotics tested were oxidized at significant rate by the LO in the presence of linoleic acid. Both dioxygenase activity and benzidine oxidation were inhibited by the known inhibitors of LO, i.e. nordihydroguaiaretic acid and eicosatriynoic acid. These findings suggest that LO may be an important pathway for xenobiotic metabolism in the rat embryo.

Fast Green Staining Of Whole Embryos For Examination And Photography

Immersion for 15 seconds in a 1:1 solution of 0.25% fast green and 95% ethyl alcohol facilitates the examination of normal and abnormal embryos for gross surface morphology and renders their surface detail highly photogenic. The method does not interfere with subsequent histological staining when the embryos are sectioned.

Who is this person? A comparison study of current three-dimensional facial approximation methods

Facial approximation is a common tool utilised in forensic human identification. Three-dimensional (3D) imaging technologies allow researchers to go beyond traditional clay models to now create virtual computed models of anatomical structures. The goal of this study was to compare the accuracy of available methods of facial approximation ranging from clay modelling to advanced computer facial approximation techniques. Two computerised reconstructions (FaceIT and FBIs ReFace) and two manual reconstructions (completed by FBIs Neville and Faraut) were completed using a skull from a known individual. A living individuals computed tomography (CT) scan was used to create a virtual 3D model of the skull and soft tissue of the face. The virtual skull models were provided to the computer-based approximation specialists. A rapid prototype of the skull was printed and provided to the practitioners who needed physical specimens. The results from all of the methods (clay and virtual) were compared visually to each other and collectively to the actual features of the living individual to compare the results of each. A quantitative study was also conducted to establish the accuracy of each method and the regions of the face that need the most improvement for all of the specialists. This project demonstrates the wide range of variation between commonly used facial identification methods. The benefit of this study was having a living individual to test the strengths and weaknesses of each method while also providing future areas of focus for soft tissue depth data studies.

Statistical analysis of the effect of cadmium and zinc on hamster teratogenesis

Maternal smoking is correlated with lower average birth weights and an increase in malformations in some studies. Increased maternal cadmium levels and reduction of zinc levels in certain tissues from fetuses of women who smoke suggest a biological association during pregnancy. Zinc has a protective effect on hamster teratogenesis caused by cadmium. To determine whether this protective effect is additive or synergistic (interactive), pregnant golden Syrian hamsters were injected (iv) on Day 8 of gestation with a test solution based on maternal body weight (0.5 ml per 100 g). Five doses were given: 2 mg/kg zinc chloride, 2 mg/kg cadmium chloride, 3 mg/kg cadmium chloride, 2 mg/kg zinc chloride plus 2 mg/kg cadmium chloride, and 2 mg/kg zinc chloride plus 3 mg/kg cadmium chloride. Fifty dams were randomly placed into one of the groups, for a total of 10 pregnant dams in each group. Twenty other dams were randomly placed into untreated or saline control groups. Fetuses were recovered on Day 15 and weighed, crown-rump length was measured, and fetuses were examined for viability and external malformations. Resorptions were noted. Statistical analyses included one- and two-way nested ANOVA, and logistic regression adjusted for litter effect. Zincs protective effect on acute cadmium embryonic/fetal toxicity and teratogenicity was confirmed. The protective effect was of the same magnitude relative to the dose-dependent effect of the cadmium exposure, indicating that the effect was statistically additive and not synergistic. This suggests that the effect depends on competition of the two elements at some common binding site(s).

Third sacral foramina morphometry for sacral neuromodulation.

Objective This study is aimed to define the geometry and location of the human S3 foramen, with respect to bony landmarks visible on ultrasound. Methods Computed tomographic (CT) image data from an institutional review board–approved database of de-identified pelvic CT images were analyzed. Points along the S3 foramina and bony sacrum were tagged, and their locations saved. The saved points were mathematically analyzed to determine the geometry and relative location of the S3 foramina with respect to other bony landmarks, specifically the sacral hiatus, and the sacral spinous processes, and the caudad aspect of the bilateral SI joints (“SI line”). Descriptive statistics were used to describe the geometry and aggregate location of the S3 foramina bilaterally. CT data sets were excluded if they had evidence of pelvic bone injury, prior bony fixation, severe osteoporosis, or other deformity. Results One hundred thirty-three data sets met the inclusion criteria. The SI line was superior to the sacral hiatus for reliable S3 localization. The entire circumference of approximately 14% of the S3 foramina is located cephalad to the SI line. The sagittal angle of trajectory for S3 was approximately 70 degrees relative to the dorsal surface of the sacrum. Conclusions Clinical localization of the S3 foramen for sacral neuromodulator needle placement is best obtained when the needle tip is positioned 15 to 25 mm lateral to the sacral spinous processes and 0.0 cm to 25 mm caudad to the SI line, at the level of the dorsal sacrum surface. The findings presented in this study may be applied to improve the efficacy and accuracy of neuromodulator lead placement into the S3 foramen. This study provides rationale for the effectiveness of the crosshair placement technique and demonstrates the best location for needle repositioning when this technique is not initially successful.

Adherence of Treponema pallidum subsp. pallidum in the Rabbit Placenta

Abstract Congenital syphilis is the consequence of transplacental passage of Treponema pallidum. A system was developed to deliver virulent T. pallidum, Nichols strain, through an isolated uterine horn of a pregnant rabbit in order to investigate the mechanism by which T. pallidum is able to cross the placenta. While the pregnant rabbit was anesthetized, the ovarian artery and the uterine vein were cannulated and attached to a peristaltic pump. Treponema pallidum (2–5 × 108 in 10−15 ml RPMI-1640) were circulated via the peristaltic pump throughout the horn for 2 hr, after which the placentas were removed, fixed in formalin, and embedded in paraffin. This system was used to investigate treponemal binding to rabbit placenta at Day 20 and 26 during the gestation period of the rabbit (29–32 days). Examination of 5–μm Dieterle silver stained tissue sections revealed (i) a greater number of spirochetes in the later gestational stage placentas (Day 26) than in the earlier placentas (Day 20), (ii) organisms adhering to the trophoblastic tissue surrounding the maternal blood channels, and (iii) organisms appearing to be in the process of penetrating the trophoblastic tissue or that had completely penetrated from the channels into the trophoblastic elements. We suggest that T. pallidum may be adhering to placental components that are differentially expressed during gestation of the rabbit.