末梢血纸片法检测血铅的方法学研究

目的 建立一种简便、快速、经济,符合我国国情的血铅检测方法。方法：选用S&S 903滤纸,首先测定滤纸的铅本底,随后检测血滴在滤纸上的扩散度,并进行纸片法血铅的重复性测定和重吸收试验。结果：①以铅标准溶液为标准测得的空白滤纸铅含量为(5.2±2.1) μg/L,经背景校正后空白滤纸铅含量为(1.3±0.4) μg/L。②血滴量在30～50 μl之间时,血液在滤纸上的扩散度和血铅浓度较恒定,血滴量少于20 μl则血铅结果偏低(P<0.01)。③在连续4周的测定中,纸片法所测血铅浓度与静脉血比较,两者具有高度相关性(r=0.9391,0.9708,0.9666,0.9553,P<0.01)。④纸片法的重吸收率为95.5%～123.7%。结论：初步建立了末梢血纸片法的血铅检测方法。     

以纸片法筛查儿童铅毒性易感性的方法学研究

目的：建立以纸片末梢血筛查儿童铅毒性易感性的方法。方法：以Chelex 100 为介质及氯仿法抽提基因组DNA,并比较二者的DNA得率。PCR扩增σ-aminolevulinate dehydratase(ALAD)基因片段,以限制性内切酶MspⅠ分析ALAD基因型。结果：以Chelex 100 为介质抽提基因组DNA的得率为 17.1 μg/ml,氯仿法抽提基因组DNA的得率为 17.5 μg/ml,两种之间的差异无显著性意义(P>0.05)。以两种方法提取的DNA为模板扩增ALAD基因片段及进行ALAD基因型分析均具有较高的特异性,但以Chelex 100 为介质抽提基因组DNA扩增时敏感性有所降低。结论：以纸片末梢血分析ALAD基因型的方法来筛查儿童铅毒性作用的易感人群在技术上是可行的。     

Neonatal Screening for Cystic Fibrosis by Dried Blood Spot Trypsin Assay

47127 newborn infants from the Emilia-Romagna region were screened for cystic fibrosis by dried blood spot trypsin assay. In the initial 12099 subjects screened with a non-standardized method, two children with cystic fibrosis were observed. Of the remaining 35028 newborn infants, 299 showed high immunoreactive trypsin values; retesting revealed persistent elevation in 11. Sweat testing confirmed cystic fibrosis in 6 subjects and was normal in 5. Clinical monitoring of these 5 children has, as yet, shown no pathological signs. No false-negative test results have yet been identified. In our region, cystic fibrosis frequency would appear to be 1 case every 5890 newborn infants. Our study confirms that elevated immunoreactive trypsin is characteristic of newborn infants with cystic fibrosis and that screening by determination of immunoreactive trypsin is of great benefit since it allows early diagnosis and a rational approach to therapy.     

纸片法筛查儿童铅中毒的可行性研究

目的　建立一种简便、快速、经济、符合我国国情的儿童铅中毒筛查方法。方法　在纸片法检测血铅的方法已经建立的基础上 ,选择 15 8例 1～ 7岁的儿童 ,同时采集静脉血和手指末梢血进行血铅分析 ,以鉴定两种检测方法的相关性。结果　 15 8例静脉血和末梢血纸片法血铅浓度的相关系数达 0 86 89,P <0 0 1。以静脉血铅 10 0和 2 0 0 μg/L为标准 ,纸片法的阳性率分别为 87 3%和10 0 % ;假阴性率分别为 15 3%和 0 ;假阳性率分别为 7 7%和 0。结论　末梢血纸片法筛查儿童铅中毒是可行的 ,在采血过程中避免污染 ,严格按操作规程进行是关键     

Development of a Screening System for Cystic Fibrosis: Meconium or Blood Spot Trypsin Assay or Both?

ABSTRACT. High blood trypsin levels during early days of life are found in newborns subsequently diagnosed to be affected by cystic fibrosis. The authors compared the validity of the traditional meconium test with the blood immunoreactive trypsin (IRT) assay, carried out in parallel on 113302 neonates from three regions of North-eastern Italy. The meconium test showed a sensitivity of 57.7%. The sensitivity of the IRT test was higher (96.1 %). It was possible to identify by IRT 10 out of 11 false negative CFs at the meconium test. A shortcoming of neonatal IRT, however, is its low specificity; 1.6% of the newborns had to be retested. A new screening policy was therefore proposed and carried out on 69 640 newborns: the Lactase test (LACT) on meconium was introduced as a complementary assay in IRT positive newborns. If LACT exceeded 2 U/g dry meconium, a confirmatory sweat test was immediately requested; if LACT test was negative and IRT exceeded 85 μg/I, IRT was repeated. Postneonatal retesting values above 25 μg/l required a sweat test. As a result, the estimated prevalence of CF was 1:4352, the sensitivity was 93.3%; the specificity turned out to be 99.6%, considering all false positive newborns investigated with retesting and/or direct sweat test.     

Screening tests for vitamin A deficiency

Objective tests for detection of xerophthalmia can solve the diagnostic problems of vitamin A deficiency under field conditions. Reliability of Rose Bengal dye test and Kajal test were tested in rural field practice area of B.J. Medical College, Pune, by finding out their correlation with prevalence of clinically detectable signs of vitamin A deficiency and serum vitamin A levels in 392 primary school children. The combination of these objective tests with clinical diagnosis may improve the detection rate of xerophthalmia.     

滤纸尿半乳糖醇气相色谱/质谱分析在筛查希特林蛋白缺陷致新生儿肝内胆汁淤积症中的应用

目的观察不同大小及不同放置时间的滤纸洗脱尿半乳糖醇气相色谱/质谱(GC/MS)检测结果与原尿液半乳糖醇GC/MS检测结果之间差异,探讨滤纸尿送检筛查希特林蛋白缺陷所致新生儿肝内胆汁淤积症(NICCD)的可行性。方法选择既往GC/MS分析提示含有半乳糖醇的原尿液10份,每份制成3种大小不同的滤纸吸附,晾干,在室温下放置1～7 d,然后洗脱。取原尿液和洗脱尿100μL,用生化分析仪测定尿肌酐水平。取原尿液和洗脱尿100μL,原尿液先采用尿素酶处理后进行尿液代谢产物GC/MS检测。用质谱仪检索NIST图谱库定性检测到的尿液代谢产物。用正十七烷酸作为内标物质,应用内标法以内生肌酐定量代谢产物。结果同一份含有半乳糖醇的尿液,制成3种大小不同的滤纸尿,放置第1、3、5、7天的大小不同滤纸洗脱尿与其原尿液均经GC/MS检测,并进行比较,发现不同时间/不同大小的滤纸洗脱尿与其原尿液半乳糖醇的出峰时间及水平,均无统计学差异,不同时间/不同大小的滤纸洗脱尿半乳糖醇的出峰时间及水平均无统计学差异。结论在常温下,7 d内当洗涤滤纸的液体与滤纸吸收的尿液量一致时,滤纸尿可代替-80℃储存的原尿。建议使用的滤纸片规格是5 cm×8 cm,可吸收1.0 mL尿液。     

A New in Vitro Screening Method for Teratogens Using Human Embryonic Palatal Mesenchymal Cells

Abstract In order to establish an in vitro screening assay system for cleft palate-inducing teratogens, we tested 31 teratogenic and 10 tionteratogenic compounds using human embryonic cultured cells. We examined whether cleft palate-inducing ability can be detected by differential growth inhibition between human embryonic palatal mesenchymal (HEPM) cells and human embryonic fibroblasts (MRC-5). Thirty one compounds with proven cleft palate-inductive effects in vivo preferentially inhibited the proliferation of HEPM cells. The average of the relative resistant rates (rate of IC50 value for HEPM cells to MRC-5 cells) of teratogens was 0.53. In contrast, almost all nonterato-gens identically inhibited the proliferation of both cell lines and the average of the relative resistant rates was 1.01. These results show that teratogens which induce cleft palate in vivo preferentially inhibit the proliferation of embryonic palatal mesenchymal cells.
The data indicated that in vitro screening using HEPM and MRC-5 cells is useful for detecting the cleft palate-inducing ability of chemicals.     

Screening for fragile X syndrome: results from a school for mentally retarded children

Fragile X syndrome is the most common inherited form of familial mental retardation. The purpose of this study was to identify yet unrecognized fragile X individuals and to estimate the frequency of both the FRAXA and FRAXE forms of the disease in a population of mentally retarded children attending a special school in Croatia. The results are reported of molecular screening of 114 children with mild to severe mental retardation. Three individuals (2.6%) with the FRAXA form of the fragile X syndrome and one boy (0.9%) with FRAXE mental retardation were detected; a total of four newly diagnosed fragile X families were identified. Closer clinical examination revealed that behavioural and speech disturbances were clearly present among all fragile X cases (both FRAXA and FRAXE), indicating that these features could be additional diagnostic criteria for the preselection of individuals at risk.

Conclusion: Fragile X screening among mentally retarded children attending a special school should be highly encouraged to reveal the cause of mental retardation and to detect yet unrecognized fragile X individuals. The frequency of fragile X syndrome in a such population in Croatia was found to correlate with similar results from previous studies. However, since at the time of diagnosis all affected families had a second or even a third child born, earlier diagnosis should be considered to provide greater benefit to fragile X families.     

The Reliability of a Single Pulse Oximetry Reading as a Screening Test for Congenital Heart Disease in Otherwise Asymptomatic Newborn Infants

Routine pulse oximetry has been studied to detect children with otherwise undiagnosed congenital heart disease prior to nursery discharge. The reported sensitivities in asymptomatic patients have been less than expected and vary widely, bringing into question the reliability of the test. The purpose of this study was to assess whether routine pulse oximetry contributes to identifying patients with critical congenital heart disease and to determine the reliability of a single pulse oximeter reading in screening asymptomatic newborn infants. Between December 26, 2003, and December 31, 2005, three hospitals in west central Florida performed a pulse oximetry routinely on all newborns at the time of discharge. Patients diagnosed with critical congenital heart disease during the study period were identified to assess whether the pulse oximetry reading initiated their diagnosis. In one hospital, the pulse oximeter data were evaluated for reliability. Downloaded data were compared to a log compiled by the nursery personnel, first without (phase 1) and then with (phase 2) their knowledge and additional training. Results were characterized as reliable, probe placed but reading not verifiable, or no evidence of probe placement. Of the 7962 infants who received oximetry testing, there were 12 postnatal diagnoses of critical congenital heart disease. None was initially identified by routine pulse oximetry. Pulse oximetry reliability improved substantially between phase 1 and phase 2 (38 v. 60%, p < 0.0001). Optimal reliability (>95%) was obtained by a nurse with a degree of LPN or higher performing an assessment of at least 360 seconds. Routine pulse oximetry was neither reliable nor an important diagnostic tool in our cohort. Important human factors (probe placement time, oximetry training, and nursing degree) impact single determination pulse oximetry reliability. With routine surveillance and quality improvement, the reliability of this test can be increased. Future studies to determine the effectiveness of pulse oximetry screening for the diagnosis of congenital heart disease in the asymptomatic newborn population must address these factors. Until such a study demonstrates acceptable sensitivity and clinical value, universal screening should not be instituted.     

Analysis of Blood Spot 17α-Hydroxyprogesterone Concentration in Premature Infants—Proposal for Cut-Off Limits in Screening for Congenital Adrenal Hyperplasia—

Blood Spot 17α-hydroxyprogesterone (17-OHP) concentrations in neonates, especially in premature babies, were determined in relation to 1) the gestational age at birth, 2) the equivalent age of gestation at blood sampling and 3) the birth weight. The 17-OHP concentrations were found to be higher with prematurity. Accordingly, the cut-off limit in screening for congenital adrenal hyperplasia (CAH) in premature infants is proposed as 20 ng/ml. Ideal cut-off limits were set by the equivalent age of gestation at blood sampling. Cut-off limits on the basis of gestational age at birth and birth weight are also suggested, where the sampling age is not so advanced. The rate of false positivity in premature infants can be reduced by this method.     

Reliability of a Single Pulse Oximetry Reading as a Screening Test for Congenital Heart Disease in Otherwise Asymptomatic Newborn Infants: The Importance of Human Factors

Background The use of routine pulse oximetry to detect neonates with undiagnosed congenital heart disease before nursery discharge has been studied. The reported sensitivities with asymptomatic patients have been less than expected and vary widely, bringing into question the reliability of the test. This study aimed to assess whether routine pulse oximetry contributes to identifying patients with critical congenital heart disease, and to determine the reliability of a single pulse oximeter reading for screening asymptomatic newborn infants. Methods Between December 26, 2003 and December 31, 2005, three hospitals in west central Florida performed pulse oximetry routinely on all newborns at the time of discharge. Patients who received a diagnosis of critical congenital heart disease during the study period were identified to assess whether the pulse oximetry reading initiated their diagnosis. In one hospital, the pulse oximeter data were evaluated for reliability. Downloaded data were compared to a log compiled by the nursery personnel, first without (Phase 1) and then with (Phase 2) their knowledge and additional training. The results were characterized as reliable, probe placed but reading not verifiable, or no evidence of probe placement. Results Among the 7,962 infants who received oximetry testing, there were 12 postnatal diagnoses of critical congenital heart disease. None was initially identified by routine pulse oximetry. Pulse oximetry reliability improved substantially between Phases 1 and 2 (38% vs 60%; p < 0.0001). Optimal reliability (>95%) was obtained by a nurse with a licensed practical nurse degree or higher performing an assessment of at least 360 s. Conclusion Routine pulse oximetry was neither reliable nor an important diagnostic tool for our cohort. Important human factors (probe placement time, oximetry training, and nursing degree) have an impact on single-determination pulse oximetry reliability. With routine surveillance and quality improvement, the reliability of this test can be increased. Future studies to determine the effectiveness of pulse oximetry screening for the diagnosis of congenital heart disease in the asymptomatic newborn population must address these factors. Until such a study demonstrates acceptable sensitivity and clinical value, universal screening should not be instituted.     

Screening for glucose-6-phosphate dehydrogenase deficiency using a modified formazan method: A pilot study on Filipino male newborns

BACKGROUND: Glucose-6-phosphate dehydrogenase (G6PD) deficiency has increased prevalence rates in tropical Africa, tropical and subtropical Asia and some parts of the Mediterranean. Earlier studies on G6PD deficiency in the Philippines have shown prevalence rates of 4.5% to 25.7%. METHODS: In the present study, 3278 male newborns were screened for G6PD deficiency using the modified formazan method, a simple screening procedure affordable in the setting of a developing country. Subjects with positive screening results were recalled for confirmatory testing using a commercial assay kit for quantitative enzyme determination. RESULTS: Of the 3278 boys studied, 186 revealed positive screening results. Of the 186, 65 boys had confirmatory testing. Of these 65 boys, 45 were confirmed to have G6PD deficiency and 20 had normal results. This study reveals an incidence of G6PD deficiency of 3.9% among male Filipinos. CONCLUSIONS: This study recommends the inclusion of G6PD deficiency in the panel of disorders for newborn screening among Filipino newborns.     

Position Paper: A national policy on asthma management for schools

Since asthma is the most common chronic illness in childhood, many of the problems associated with this condition will impact on the child's education. Because of widespread concerns regarding the management of asthma in schools, a subcommittee of the Thoracic Society of Australia and New Zealand, Asthma Special Interest Group, was convened to draw up national guidelines for school staff in order to provide optimal management of asthma in the school setting. We used current medical literature and the clinical experience of the authors who have dealt with children and adolescents suffering from asthma in the hospital, community and school environment. A number of issues had been identified, including: the availability of an asthma first aid kit; correct use of bronchodilator aerosols by puffer and spacer devices; and clear instructions as to when to notify parents and when to call an ambulance to the school.
To provide optimal care of asthma in the school setting, the committee made the following recommendations: (i) improved guidance and training of school teachers and ancillary staff in appropriate asthma care; (ii) improved recognition by schools of those students with asthma; (iii) schools should encourage a policy of exercise for all students with asthma; (iv) asthma medication should be readily available at all times to those students with asthma; (v) the safety of school excursions and school camps should be improved by having available personnel competent in acute asthma management; a mobile asthma first aid kit; and by ensuring the student continues taking their usual asthma medications throughout the excursion; (vi) the early introduction of a 'lung health' education programme for all students, with particular emphasis on asthma being encouraged. We believe that asthma management in schools would be optimized if this national policy were adopted throughout Australian schools.     

Hypothyroidism in Children with Filter Paper TSH of 30 to 50 μU/ml at Initial Screening Implication of the TSH Cut-off Point for Recalling of Infants at Risk

ABSTRACT. In a systematic screening of newborns in France daring the period from 1979 to 1983, 959 infants with hypothyroidism were detected. In 16 cases of confirmed hypothyroidism the initial filter paper TSH (FP-TSH) was between 30 and 50 μU/ml. These cases emphasize the necessity of keeping a Y"security zone" for FP-TSH value between 30 and 50 (μU/ml and of recalling these patients for a second test filter paper TSH.