Manea-Krichten M, Patterson C, Miller G, Settle D, Erel Y
Chemistry Department, University of California, Irvine 92175.
Sci Total Environ. 1991 Sep;107:179-203. doi: 10.1016/0048-9697(91)90259-h.
Lead and Ba in postmortem tooth enamel, rib and ulna of six contemporary people (67-96 years; ave. 80) were shown to exhibit similar accumulations with age in the three different types of osseous tissue: Pb/Ca (wt) = 3.0, 5.2, and 3.9 x 10(-5) in rib, ulna, and tooth enamel; and Ba/Ca (wt) = 2.4, 2.4, and 1.8 x 10(-5) in rib, ulna, and tooth enamel, respectively. Mean concentrations of Pb were 11, 19, and 14 micrograms g-1 in rib (ash), ulna (ash), and enamel (dry), respectively. Means for Ba were 8.7, 8.9, and 6.4 micrograms g-1 in rib (ash), ulna (ash), and enamel (dry), respectively. Comparison of Ba in ulna of our 80-year-old subjects with Ba determined by other investigators in bones of younger contemporary populations indicated that Ba accumulates with age at about half the rate of Pb accumulation in bone. Concentrations of Ba in rib, ulna and enamel were positively correlated and similar within an individual, but varied among subjects in proportion to variations in absorptive uptake in portal blood. Barium may diffuse from a blood-dentine source into enamel, where it replaces Ca and accumulates with age. Because of extreme Pb pollution of our 80-year-old subjects and its variation of intake with age, the correlation of Pb in tooth enamel with Pb in bone was more scattered than for Ba. It is shown by means of stable Pb isotopic tracers that: (i) among the three types of osseous tissue, the residence time of Pb is longest in enamel, where it apparently accumulates with age by diffusion with little loss through exchange; and (ii) the residence time of Pb is longer in compact ulna than in trabecular rib, as it accompanies Ca in its osteoblastic transfer from blood to bone and then in its osteoclastic transfer back to blood from bone.
在六名当代人（67 - 96岁；平均80岁）的死后牙釉质、肋骨和尺骨中，铅和钡在三种不同类型的骨组织中随年龄呈现出相似的累积情况：肋骨、尺骨和牙釉质中的铅钙比（重量比）分别为3.0×10⁻⁵、5.2×10⁻⁵和3.9×10⁻⁵；肋骨、尺骨和牙釉质中的钡钙比（重量比）分别为2.4×10⁻⁵、2.4×10⁻⁵和1.8×10⁻⁵。肋骨（灰分）、尺骨（灰分）和牙釉质（干燥）中铅的平均浓度分别为11、19和14微克/克。钡在肋骨（灰分）、尺骨（灰分）和牙釉质（干燥）中的平均值分别为8.7、8.9和6.4微克/克。将我们80岁受试者尺骨中的钡与其他研究者测定的较年轻当代人群骨骼中的钡进行比较表明，钡在骨骼中的累积速率约为铅累积速率的一半。肋骨、尺骨和牙釉质中钡的浓度在个体内部呈正相关且相似，但在不同受试者之间因门静脉血液中吸收摄取的差异而有所不同。钡可能从血 - 牙本质源扩散到牙釉质中，在那里它取代钙并随年龄累积。由于我们80岁受试者铅污染极其严重且其摄入量随年龄变化，牙釉质中的铅与骨骼中的铅之间的相关性比钡的相关性更为分散。通过稳定铅同位素示踪剂表明：（i）在三种骨组织类型中，铅在牙釉质中的停留时间最长，在那里它显然通过扩散随年龄累积，通过交换损失很少；（ii）铅在致密的尺骨中的停留时间比在小梁状肋骨中更长，因为它在成骨细胞从血液向骨骼的转移过程中与钙一起，然后在破骨细胞从骨骼向血液的转移过程中也是如此。
