Low arylsulphatase A activity and choreoathetotic syndrome in three siblings: differentiation of pseudodeficiency from metachromatic leukodystrophy

We report on a family with a sibship of three children for whom the diagnosis of an unusual form of metachromatic leukodystrophy (MLD) had been suggested earlier. The patients had choreiform movements and dystomic posturing accompanied by dysarthria since childhood. The availability of the polymerase chain reaction enabled us to show that the three siblings have a pseudodeficiency genotype (ASA_p/ASA_p). There was no abnormal sulphatiduria, and we propose that the neurological disease and low arylsulphatase A activity are unrelated to one another in this family. A diagnosis of MLD carries very serious implications, and we recommend that gene amplification by polymerase chain reaction and hybridization with allele-specific oligonucleotide probes should be used to corroborate the diagnosis, especially when there is no abnormal sulphatiduria and when metachromatic material cannot be demonstrated in a sural nerve biopsy.     

Variability in organochlorine analysis in fish: An interlaboratory study and its implications for environmental monitoring and regulatory standards

Samples of muscle, from four types of fish, that had been spiked at 0.25 and 1.0 mg/kg with hexachlorobenzene (HCB), gamma BHC (lindane), technical chlordane, p,p-DDT, p,p-DDE and p,p-DDD were analyzed by eight laboratories. Some laboratories could not reliably detect organochlorine compounds even though they were registered as national testing laboratories. The analytical accuracies of laboratories that were able to reliably detect the spiked compounds were very variable and exceeded acceptable limits. Within-laboratory precision was generally acceptable. There was significant interlaboratory variability among the estimates of percent lipid for each fish type. This variability negated the use of percent lipid for standardization of organochlorine concentrations for comparison between studies.The results highlight the need for standard analytical protocols that are regularly tested by interlaboratory studies. They also indicate that interchangeability of data between studies is limited due to low analytical accuracy. Therefore, comparison of analytical data to absolute environmental and regulatory standards is difficult. The use of latitudinal confidence ranges when setting regulatory standards is recommended.     

Cholecystokinin and satiety in rats and rhesus monkeys.

When ingested food does not accumulate in the stomach or enter the small intestine, rats do not stop eating. Small amounts of food placed in the small intestine or intraperitoneal injections of the intestinal hormone cholecystokinin (CCK) elicit the full behavioral display of satiety in these sham-feeding rats. In rhesus monkeys, intravenous infusions of CCK produce large, dose-related reductions in meal size. In addition, gastric preloads of calorically trivial amounts of l-phenylalanine, but not d-phenylalanine, produce large reductions in meal size, suggesting that: 1) endogenous CCK acts as a "satiety signal," and 2) certain foods may be very efficient releasers of such a satiety signal. Whether the satiety effect of CCK is physiological in rats and monkeys or operates in humans has not been determined.     

Hemoglobin and albumin adducts of benzene oxide among workers exposed to high levels of benzene

Benzene oxide (BO) reacts with cysteinyl residues in hemoglobin (Hb) and albumin (Alb) to form protein adducts (BO-Hb and BO-Alb), which are presumed to be specific biomarkers of exposure to benzene. We analyzed BO-Hb in 43 exposed workers and 42 unexposed controls, and BO-Alb in a subsample consisting of 19 workers and 19 controls from Shanghai, China, as part of a larger cross-sectional study of benzene biomarkers. The adducts were analyzed by gas chromatography-mass spectrometry following reaction of the protein with trifluoroacetic anhydride and methanesulfonic acid. When subjects were divided into controls (n = 42) and workers exposed to < or =31 (n = 21) and >31 p.p.m. (n = 22) benzene, median BO-Hb levels were 32.0, 46.7 and 129 pmol/g globin, respectively (correlation with exposure: Spearman r = 0.67, P < 0.0001). To our knowledge, these results represent the first observation in humans that BO-Hb levels are significantly correlated with benzene exposure. Median BO-Alb levels in these 3 groups were 103 (n = 19), 351 (n = 7) and 2010 (n = 12) pmol/g Alb, respectively, also reflecting a significant correlation with exposure (Spearman r = 0.90, P < 0.0001). The blood dose of BO predicted from both Hb and Alb adducts was very similar. These results clearly affirm the use of both Hb and Alb adducts of BO as biomarkers of exposure to high levels of benzene. As part of our investigation of the background levels of BO-Hb and BO-Alb found in unexposed persons, we analyzed recombinant human Hb and Alb for BO adducts. Significant levels of both BO-Hb (19.7 pmol/g) and BO-Alb (41.9 pmol/g) were detected, suggesting that portions of the observed background adducts reflect an artifact of the assay, while other portions are indicative of either unknown exposures or endogenous production of adducts.      

Increased aneusomy and long arm deletion of chromosomes 5 and 7 in the lymphocytes of Chinese workers exposed to benzene

Two of the most common cytogenetic changes in therapy- and chemical- related leukemia are the loss and long (q) arm deletion of chromosomes 5 and 7. The detection of these aberrations in lymphocytes of individuals exposed to potential leukemogens may serve as useful biomarkers of increased leukemia risk. We have used a novel fluorescence in situ hybridization (FISH) procedure to determine if specific aberrations in chromosomes 1, 5 and 7 occur at an elevated rate in the blood cells of workers exposed to benzene. Forty-three healthy workers exposed to a wide range of benzene concentrations (median 31 p.p.m., 8 h time-weighted average) and 44 unexposed controls from Shanghai were studied. Whole blood was cultured and metaphase spreads were harvested at 72 h. Benzene exposure was associated with increases in the rates of monosomy 5 and 7 but not monosomy 1 (P < 0.001, P < 0.0001 and P = 0.94, respectively) and with increases in trisomy and tetrasomy frequencies of all three chromosomes. Long arm deletion of chromosomes 5 and 7 was increased in a dose-dependent fashion (P = 0.014 and P < 0.0001) up to 3.5-fold in the exposed workers. These results demonstrate that leukemia-specific changes in chromosomes 5 and 7 can be detected by FISH in the peripheral blood of otherwise healthy benzene-exposed workers. We suggest that aberrations in chromosomes 5 and 7 may be useful biomarkers of early biological effect for benzene exposure.      

Uroepithelium in a colonic diverticulum

Giant colonic diverticula are rare entities and often present in adulthood as acute diverticulitis. The authors present a case of giant colonic pseudodiverticulum lined with uroepithelium causing bowel obstruction in a neonate. The presence of uroepithelium in a colonic pseudodiverticuium remains unexplained and to the authors' knowledge unreported. This heterotopic tissue may be a result of an embryonic rest or could be urachal in origin adhering initially to the colon and eventually detaching from the umbilicus. These lesions should be resected because of the risk of infection, perforation, or obstruction.     

新生儿复苏培训项目十年回顾

每年约2000万新生儿出生的中国，鼓励一对夫妻只生一个孩子，随着国民经济迅速发展，生活水平不断提高，每一个新生儿的健康都受到家庭及社会的高度关注。1991年中国要儿死亡率为50．2‰，1998年降至33．3‰，地区性差别很大，贫困地区最高可达56‰，一些条件较好的城市低至7．5‰。围产医学界公认围产窒息为要儿患病及死亡的首要原因，如合并早产、严重肺、脑疾病等后果更为严重。