Skull from Spruce Swamp: Case of Cranial Dysraphism?

Abstract

219 + 23 and 218-L 20 (1); and 222.4 + 22.4 and 219.6 24.1 (5) based on measurements with two different, commercially available, potassium ion-specific electrodes. To evaluate the applicability of this algebraic extrapolation, I calculated values for Kf1 for each of the measurements made above pH 9 (5, tables 1 and 2 Rather we have made our measurements directly in a region of ionic strength where meaningful activity coefficients may be used. Thus, our method yields thermodynamic rather than conditional values.2) Melchior does not take into account the effect of the supporting electrolyte used to control ionic strength in the earlier studies. As we have explicitly pointed out (2), an apparent lowering of the formation constant will be produced if the cation of the electrolyte associates with ATP. No additional cations are used in our study.3) As Melchior himself points out, there is no reliable method for extrapolating our thermodynamic formation constant values to media of high ionic strength. A rough estimate has shown (2) that our value would still substantially exceed earlier values at 0.2M ionic strength, even if the leveling effect of the electrolyte cation is neglected.Finally, we cannot support Melchior's suggestions that conditional values for formation constants should be used in biochemical calculations in preference to thermodynamic values.Indeed, we feel that the use of nonthermodynamic quantities is only justified as an expedient when rigorous values are not available. In those studies where electrolytes used to maintain ionic strength contain ions not even present in biological media, the validity of the resulting conditional constants is especially questionable.

A probable example of cranial dysraphism from New Orleans, Louisiana

“…The majority of the bioarchaeological literature identifies defects located at bregma as congenital herniations/dysraphisms (Gass, ; Ortner, ; Powell, ; Stewart, ; Webb & Thorne, ), although some lesions are more difficult to assess resulting in diagnoses that remain undifferentiated (Blau, ; Sublett & Wray, ). Only six examples of defects at bregma exist in the literature and consistent in each of these papers is the description of the shape, position, and location of the defect (Table ).…”

“…Powell concluded that the best explanation was trephination, although he did allude to a potential diagnosis of an aperture allowing for herniation of the meninges and brain tissue. Gass (), a neurosurgeon, read Powell's report and noted that the appearance of the anomaly was more consistent with an encepholocele or meningoencepholocele. He describes the condition thusly: “the skull may become ‘saucerized’ also by benign tumors within it and growing out of it, or resting upon it” and that “when this process is present exactly in the midline and an aperture is pierced through the skull at the bottom of the ‘saucer’” one can be confident in a diagnosis of cranial dysraphism (Gass, :1268).…”

“…Gass (), a neurosurgeon, read Powell's report and noted that the appearance of the anomaly was more consistent with an encepholocele or meningoencepholocele. He describes the condition thusly: “the skull may become ‘saucerized’ also by benign tumors within it and growing out of it, or resting upon it” and that “when this process is present exactly in the midline and an aperture is pierced through the skull at the bottom of the ‘saucer’” one can be confident in a diagnosis of cranial dysraphism (Gass, :1268). Sublett and Wray () described an example of trephination of a middle‐aged adult female with a defect located directly over bregma.…”

“…There is no visible saucer present; however, such an absence may be due to the young age of the individual that a depression did not form. Barnes () summarises defects in the axial skeleton, including encephaloceles, meningoceles, and cysts, indicating that an encephalocele will be larger and bifid whereas the meningocele is likely to occur at bregma citing the analyses given by Powell (), Gass (), Stewart (), Webb and Thorne (), and Ortner (). Additionally, with regard to defect shape Barnes states that “the resulting cyst produces a smooth, rounded depression in the outer surface of the cranium” and “the borders of the depression are sharply defined, surrounded by an outer flange of built‐up bone” (1994:52).…”

“…Published reports regarding cranial lesions located at bregma are common, with several examples from around the world in both the bioarchaeological and clinical literature (Blau, ; Drolet, ; Drolet, Clowry, McTigue, & Esterly, ; Gass, ; Held, Rose, Hamm, & Fölster‐Holst, ; Ortner, ; Powell, ; Stewart, ; Sublett & Wray, ; Webb & Thorne, ). The bioarchaeological literature tends to identify a particular type of bregmatic lesion as cranial dysraphism.…”