Petkova V, Adjarov D, Pavlova S, Naydenova E, Kerimova M, Kuneva T
Clinica di Malattie Professionali, Ospedale Facoltativo San Ivan Rilksi, Sofia, Bulgaria.
Med Lav. 1994 Jul-Aug;85(4):299-308.
The results of EDTA therapy were studied in 37 workers of a battery factory consisting of males with varying degrees of occupational lead poisoning (low exposure: 10 subjects, blood lead levels (PbB) lower than 400 micrograms/l with slight alterations in heme biosynthesis; beyond limit of effect: 5 subjects, PbB > 400 micrograms/l; slight intoxication: 19 subjects, with marked alterations in heme synthesis and preclinical signs of intoxication; average degree of intoxication: 3 subjects with clinical signs of intoxication. Clinical symptoms and the following parameters were investigated: blood lead (PbB), delta-aminolevulinic acid dehydratase in erythrocytes (ALA-D), zinc protoporphyrin (PP) in erythrocytes and delta-aminolevulinic acid (ALA) in 24-hour urine before and after EDTA chelating therapy. Simultaneous measurement of ALA-D and PP showed high diagnostic sensitivity in detecting lead poisoning in occupationally exposed subjects. In view of the high interindividual variability of the results, these indices did not, however, permit a useful differentiation to be made of the different degrees of intoxication at individual level, even though a good correlation was observed between PbB and porphyrin metabolism indices. From the alterations observed in ALA-D and PP values it was not possible to establish an association between degree of alteration and types of clinical symptoms in the different intoxication studies. At the end of EDTA treatment, a clinical improvement was observed in all cases studied but only in 5 cases was a reduction in PbB observed, to levels below 1.20 mol/l, which is accepted as a permissible limit for the general population; in 17 cases PbB remained at levels above the critical value for occupational lead poisoning (400 micrograms/l), although there was a decrease after treatment. The improvement observed in the indices of porphyrin metabolism at the end of treatment was only slight: significant variations were measured only for PbB. After treatment no association was observed between ALA-D and PP variations in erythrocytes and improvement in clinical symptoms; measurement of these indices therefore seems to be of little use in assessing the efficacy of the treatment. In spite of its limited diagnostic sensitivity during intoxication, measurement of ALA in urine could be useful to assess the efficacy of chelating therapy in subjects in whom the values are initially altered.
对一家电池厂的37名男性工人进行了乙二胺四乙酸（EDTA）疗法的研究，这些工人患有不同程度的职业性铅中毒（低暴露组：10名受试者，血铅水平（PbB）低于400微克/升，血红素生物合成有轻微改变；超过效应限度组：5名受试者，PbB>400微克/升；轻度中毒组：19名受试者，血红素合成有明显改变且有中毒的临床前体征；中度中毒组：3名有中毒临床症状的受试者。研究了临床症状以及以下参数：EDTA螯合治疗前后的血铅（PbB）、红细胞中的δ-氨基乙酰丙酸脱水酶（ALA-D）、红细胞中的锌原卟啉（PP）和24小时尿中的δ-氨基乙酰丙酸（ALA）。同时测量ALA-D和PP在检测职业暴露受试者的铅中毒方面显示出高诊断敏感性。然而，鉴于结果的个体间差异很大，尽管观察到PbB与卟啉代谢指标之间有良好的相关性，但这些指标在个体水平上并不能对不同程度的中毒进行有效的区分。从观察到的ALA-D和PP值的变化中，无法在不同中毒研究中确定变化程度与临床症状类型之间的关联。在EDTA治疗结束时，所有研究病例均观察到临床改善，但仅5例观察到PbB降低至低于1.20微摩尔/升的水平，这被认为是一般人群的允许限值；17例患者的PbB仍高于职业性铅中毒的临界值（400微克/升），尽管治疗后有所下降。治疗结束时观察到的卟啉代谢指标的改善仅轻微：仅PbB有显著变化。治疗后，未观察到红细胞中ALA-D和PP的变化与临床症状改善之间的关联；因此，测量这些指标在评估治疗效果方面似乎用处不大。尽管尿中ALA在中毒期间的诊断敏感性有限，但对初始值改变的受试者，测量尿中ALA可能有助于评估螯合治疗的效果。
