Banea-Mayambu J P, Tylleskär T, Gitebo N, Matadi N, Gebre-Medhin M, Rosling H
Centre National de Planification de Nutrition Humaine, Kinshasa, Democratic Republic of Congo.
Trop Med Int Health. 1997 Dec;2(12):1143-51. doi: 10.1046/j.1365-3156.1997.d01-215.x.
High cyanide intake from consumption of insufficiently processed cassava has been advanced as a possible aetiology of the upper motor neurone disease konzo. However, similar neurodamage has not been associated with cyanide exposure from any other source. With an ecological study design, we compared 22 cases of konzo, 57 unaffected household members and 116 members from unaffected households, a total of 195 subjects, in konzo-affected savanna villages with 103 subjects in adjacent non-affected forest villages in the Paykongila area in the Bandundu Region, Zaire. In the dry season, the mean value (+/- SEM) of urinary thiocyanate, the main cyanide metabolite, was higher in the three groups in konzo-affected villages (563 +/- 105, 587 +/- 44 and 629 +/- 47 micromol/l) than in unaffected villages (241 +/- 17 micromol/l). In affected villages in the dry season when konzo incidence was high, mean urinary thiocyanate was also higher than the levels found in the wet season when incidence was low. The wet season values (mean +/- SEM) were 344 +/- 60, 381 +/- 35 and 351 +/- 27 micromol/l. Urinary levels of inorganic sulphate were low in all groups, indicating low intake of the sulphur amino-acids which provide a substrate for cyanide detoxification. These findings support an aetiological role for cyanide in konzo. However, urinary linamarin, the cyanogenic glucoside and source of cyanide in cassava, was more closely associated with the occurrence of konzo. The mean value (+/- SEM) of urinary linamarin in the konzo cases was 632 +/- 105 micromol/l and in their household members 657 +/- 52 micromol/l, which was significantly higher than in members of control households in the same village (351 +/- 28 micromol/l) and in unaffected villages (147 +/- 18 micromol/l). This suggests that a specific neurotoxic effect of linamarin, rather than the associated general cyanide exposure resulting from glucoside breakdown in the gut, may be the cause of konzo.
食用加工不充分的木薯导致高氰化物摄入，这被认为可能是上运动神经元疾病konzo的病因。然而，尚未发现其他来源的氰化物暴露会导致类似的神经损伤。我们采用生态学研究设计，在扎伊尔班顿杜地区Paykongila地区受konzo影响的稀树草原村庄，将22例konzo病例、57名未患病的家庭成员和116名来自未患病家庭的成员（共195名受试者）与相邻未受影响的森林村庄的103名受试者进行了比较。在旱季，受konzo影响村庄的三组人群（分别为563±105、587±44和629±47微摩尔/升）尿硫氰酸盐（主要的氰化物代谢产物）的平均值（±标准误）高于未受影响村庄（241±17微摩尔/升）。在旱季konzo发病率高时，受影响村庄的尿硫氰酸盐平均值也高于雨季发病率低时的水平。雨季的数值（平均值±标准误）分别为344±60、381±35和351±27微摩尔/升。所有组的尿无机硫酸盐水平都很低，表明硫氨基酸摄入量低，而硫氨基酸是氰化物解毒的底物。这些发现支持了氰化物在konzo病因中的作用。然而，尿中亚麻苦苷（木薯中的含氰糖苷和氰化物来源）与konzo的发生更为密切相关。konzo病例尿中亚麻苦苷的平均值（±标准误）为632±105微摩尔/升，其家庭成员为657±52微摩尔/升，显著高于同村对照家庭的成员（351±28微摩尔/升）和未受影响村庄的成员（147±18微摩尔/升）。这表明，亚麻苦苷的特定神经毒性作用，而非肠道中糖苷分解产生的相关一般性氰化物暴露，可能是konzo的病因。
