Biomedical subjects

Bruno Frohlich

Publications and source records attributed to Bruno Frohlich.

3 recordsLinked to original sources

PubMed2006

Assessment of age at death by microscopy: unbiased quantification of secondary osteons in femoral cross sections.

The microscopic method of age at death determination was introduced by Kerley in 1965 [E.R. Kerley, The microscopic determination of age in human bone, Am. J. Phys. Anthropol, 23 (1965) 149-163.]. However, even though the method has been revised several times, there remain some fundamental issues concerning the reliability of the methods. This is because several basic histological features seen in a cross section of a bone have to be quantified according to the method, but the definition, and hence quantification, of these features leaves room for subjectivity. In a previous study we found that some of these features (osteon fragments and Haversian canals) could not be identified reliably. Only secondary osteons could be identified with a low inter and intra observer error. Furthermore, since the histological features are quantified in only parts of an entire bone cross section, the selection of these parts or areas is a potential source of bias. Finally, unless an unbiased method is used for addressing features on the borders of the selected areas, this will also introduce error. These issues have not been addressed specifically in previous studies. In this study, we used the methods of stereology to choose the regions of interest, as well as for dealing with border phenomena, and we only counted secondary osteons. Our results show a statistically significant increase in the median number of osteons per area unit with increasing age at death. However, this was after exclusion of one outlier. This result is probably due to the limited sample size (N = 24). As such, this study is preliminary, but does warrant applying the described techniques to a larger sample.

Adolescent↗

PubMed2003

Probable destructive meningioma in an archaeological adult male skull from Alaska.

Several intracranial pathological conditions can affect the bones of the skull. The most common cause of these conditions is tumor, but infection and other diseases are also known to affect the bones of the skull. Distinguishing between the various causes of intracranial skeletal pathology in archaeological human remains is usually a challenging exercise, and a specific diagnosis will often be impossible. Meningiomas are tumors that arise in arachnoid tissues embedded in the outer layer of the dura. Because of this association, they occur almost exclusively in the skull and vertebral column. Usually meningiomas are slow-growing tumors that do not metastasize to other organs and tissues of the body. However, rare cases can be malignant and, even when meningiomas are benign, their presence and growth can adversely affect the nervous and vascular supply to other tissues in the skull and vertebral column. Their effect on adjacent bone tissue varies from stimulating bone-forming lesions to causing highly destructive lesions. A few examples of meningioma have been described in the paleopathological literature. Most of these cases are bone-stimulating meningiomas. The case presented here is a probable example of a highly destructive meningioma of the skull base, with unilateral extension into the left side of the cranium. This case is compared with a modern clinical case of destructive intracranial meningioma that was documented both radiographically and pathologically. Destructive meningiomas can be confused with other pathological conditions, including benign and malignant tumors. Criteria for differentiating the diagnostic options are reviewed.

Adult↗

PubMed2003

Reconstructing cetacean brain evolution using computed tomography.

Until recently, there have been relatively few studies of brain mass and morphology in fossil cetaceans (dolphins, whales, and porpoises) because of difficulty accessing the matrix that fills the endocranial cavity of fossil cetacean skulls. As a result, our knowledge about cetacean brain evolution has been quite limited. By applying the noninvasive technique of computed tomography (CT) to visualize, measure, and reconstruct the endocranial morphology of fossil cetacean skulls, we can gain vastly more information at an unprecedented rate about cetacean brain evolution. Here, we discuss our method and demonstrate it with several examples from our fossil cetacean database. This approach will provide new insights into the little-known evolutionary history of cetacean brain evolution.

Animals↗