Evidence of genetic variation for α-N-acetyl-D-glucosaminidase in black and white populations: A new polymorphism

Serum and/or plasma samples from 360 Whites and 126 Blacks were assayed for activity of the lysosomal hydrolase α-N-acetyl-D-glucosaminidase (NAG). The samples from the Blacks had an increased mean (0.50 nm/ml/min) and standard deviation (0.30 nm/ml/min) compared to those from the Whites (0.29 nm/ml/min and 0.10 nm/ml/min, respectively). After log_e transformation and admixture analysis, it was possible to demonstrate the presence of 3 distributions of NAG activity in Blacks and at least 2 in Whites. Segregation analysis of the NAG activity of 29 White half-sib twin families indicated that a genetic model for the inheritance of NAG activity provided a better fit (P < 0.01) with the data than the “environmental” model. Thus, the study suggests the presence of a genetic polymorphism for NAG activity in Black and White populations. The presence of alleles for high and low NAG activity in the normal population could lead to incorrect interpretation of serum carrier tests for Sanfilippo syndrome, type B.     

Organization of the thalamostriatal projections in the rat, with special emphasis on the ventral striatum

The organization of the thalamic projections to the ventral striatum in the rat was studied by placing injections of the retrograde tracer cholera toxin subunit B in the ventral striatum and small deposits of the anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHA-L) in individual midline and intralaminar thalamic nuclei. In order to provide a complete map of the midline and intralaminar thalamostriatal projections, PHA-L injections were also made in those parts of the intralaminar nuclei that project to the dorsal striatum. The relationship of thalamic afferent fibres with the compartmental organization of the ventral striatum was assessed by combining PHA-L tracing and enkephalin immunohistochemistry. The various midline and intralaminar thalamic nuclei project to longitudinally oriented striatal sectors. The paraventricular thalamic nucleus sends most of its fibres to medial parts of the nucleus accumbens and the olfactory tubercle, whereas smaller contingents of fibres terminate in the lateral part of the nucleus accumbens and the most ventral, medial, and caudal parts of the caudate-putamen complex. The projections of the parataenial nucleus are directed towards central and ventral parts of the nucleus accumbens and intermediate mediolateral parts of the olfactory tubercle. The intermediodorsal nucleus projects to lateral parts of the nucleus accumbens and the olfactory tubercle and to ventral parts of the caudate-putamen. The projection of the rhomboid nucleus is restricted to the rostrolateral extreme of the striatum. A diffuse projection to the ventral striatum arises from neurons ventral and caudal to the nucleus reuniens rather than from cells inside the nucleus. Fibres from the central medial nucleus terminate centrally and dorsolaterally in the rostral part of the nucleus accumbens and medially in the caudate-putamen. Successively more lateral positions in the caudate-putamen are occupied by fibres from the paracentral and central lateral nuclei, respectively. The lateral part of the parafascicular nucleus projects to the most lateral part of the caudate-putamen, whereas projections from the medial part of this nucleus terminate in the medial part of the caudate-putamen and in the dorsolateral part of the nucleus accumbens. Furthermore, a rostral to caudal gradient in a midline or intralaminar nucleus corresponds to a dorsal to ventral and rostral to caudal gradient in the striatum. In the ventral striatum, thalamic afferent fibres in the "shell" region of the nucleus accumbens avoid areas of high cell density and weak enkephalin immunoreactivity.(ABSTRACT TRUNCATED AT 400 WORDS)     

Hydrolysis of Carbonates,Thiocarbonates, Carbamates,and Carboxylic Esters of α-Naphthol, β-Naphthol,and p-Nitrophenol by Human,Rat, and Mouse Liver Carboxylesterases

Thirty carbonates, thiocarbonates, carbamates, and carboxylic esters of -naphthol, -naphthol, and p-nitrophenol were synthesized and tested as substrates for liver carboxylesterases from the crude microsomal fractions of human and mouse, and purified isozymes, hydrolases A and B, from rat liver microsomes. The carbonates, thiocarbonates, and carboxylic esters of -naphthol were cleaved more rapidly than the corresponding -naphthol isomers by the mammalian liver esterases. -Naphthyl esters of acetic, propionic, and butyric acids were among the best substrates tested for these enzymes. The majority of the substrates was consistently hydrolyzed at higher rates by hydrolase B compared with hydrolase A, although the Michaelis–Menten constant (K _m) values of selected substrates differed widely with these two isozymes. Malathion was a 15-fold better substrate for hydrolase B than for hydrolase A. Compared with the corresponding carboxylates, the carbonate moiety of - and -naphthol and p-nitrophenol lowered the specific activities of the enzymes by about fivefold but improved stability under basic conditions. The optimum pH of mouse liver esterase with the acetate, methylcarbonate, and ethylthiocarbonate of -naphthol was between pH 7.0 and pH 7.6. Human and mouse liver microsomal esterase activities were about five orders of magnitude lower than the esterase activities of purified rat liver hydrolase B. A relationship between the catalytic activity of the enzymes and the lipophilicity of the naphthyl substrates indicated that (i) in the - and -naphthyl carbonate series, an inverse relationship between enzyme activity and lipophilicity of the substrates was observed, whereas (ii) in the -naphthyl carboxylate series, an increase in enzyme activity with increasing lipophilicity of the substrates up to a log P value of about 4.0 was observed, after which the enzyme activity decreased.     

Hepatitis a virus identification in an outbreak by enzymatic amplification

From April 28th to May 22nd, 1987, the Medical Authority identified 13 cases (6 symptomatic cases) of hepatitis A (HA) in a school and in a college of Rome.The principal risk factor was determined to be full-time presence at the State school and boarders at the college. The distribution of HA cases suggested a person to person contact; antihepatitis A virus IgM were identified in 12 out of 13 cases with high levels of transaminases.During the disease epidemic, water samples were taken from the well of the college for bacteriological and virological analyses. The water was classified as undrinkable due to the presence of 16 total coliforms/100 ml and 35 total bacteria count at 36° C.Fecal coliforms, fecal streptococci and sulfite reducing clostridia were absent. Two water samples of 100 liters were collected and concentrated by adsorption-elution method on electropositive membranes or by ultrafiltration using a Millipore apparatus.Infectious Hepatitis A virus was only isolated from samples concentrated by adsorption-elution method on electropositive membranes using tissue culture methods and subsequently HA virus was identified by other traditional methods (Elisa and immunofluorescence). In contrast, PCR test performed on the concentrated samples, was positive only for the ultraconcentrated sample. The positivity of the PCR test confirmed the presence of the Hepatitis A virus in the well water.     

抗—HBcIgM在HBV感染55例中的动态观察

本文ELLSA检测,对55例HBV感染者血清中的抗-HBcIgM随访研究其动态变化。结果发现,急性乙肝35例抗-HBcIgM的阳性率在入院时,6个月,12个月分别为100%（35/35）,86%（31/36）,及34%（6/18）,提示抗-HBcIgM在6个月大都保持阳性,至12个月大部分消失;“无症状”携带者20例抗-HBcIgM阳性率在首检时,6个月,24个月都为100%（各为20/20,17/17,及10/10）,提示“无症状”携带者的抗-HBcIgM很难自然消失,同时把抗-HBcIgM和HBsAg检测对比,提示HBsAg阴性不能排除急性乙肝的诊断。     

Depression of drug metabolizing activity in the human liver by interferon-α

Summary The depressant effect of interferon- on drug metabolizing activity in the liver has been investigated in 12 patients with chronic active hepatitis B. 7-methoxy-coumarin (7-MC) O-demethylase and 7-ethoxycoumarin (7-EC) O-deethylase, in specimens obtained by liver biopsy, were measured before and after interferon treatment. 7-MC and 7-EC O-dealkylase activity were significantly reduced after interferon treatment, from 13.4 to 9.24 nmol·g^–1 liver·min^–1, and from 3.22 to 2.16 nmol·g^–1 liver·min^–1, respectively. The magnitude of the fall varied widely between individual patients. The study provides the first direct evidence that interferon- can impair the activity of drug metabolizing enzymes in the human liver.     

EB病毒LMP1在鼻咽癌细胞中通过IκBα的降解活化NF-κB

目的　阐明鼻咽癌细胞中EB病毒编码的潜伏膜蛋白 1(LMP1)活化核转录因子NF κB的机制。方法　利用强力霉素Dox诱导表达LMP1的鼻咽癌细胞株Tet on LMP1 HNE2为实验模型 ,首先应用免疫印迹方法测定Dox诱导后不同时相LMP1的表达动力学以及IκBs蛋白量及功能的改变。进而用间接免疫荧光法检测NF κB的亚细胞定位。最后采用瞬间共转染及报道基因活性分析分析NF κB的活性。结果　在鼻咽癌细胞Tet on LMP1 HNE2中 ,Dox处理 15分钟后LMP1的表达迅速升高并维持与较高水平直至 12 0分钟。LMP1的诱导性表达导致IκBα的磷酸化并降解 ,但IκBα蛋白总量无改变。继IκBα的磷酸化并降解 ,NF κB(P6 5 )自胞浆易位至胞核且活性升高。IκBα的显性负性突变子抑制NF κB(P6 5 )的核易位及报道活性。LMP1的诱导性表达并未引起IκBβ蛋白水平变化。结论　在鼻咽癌细胞Tet on LMP1 HNE2中 ,EB病毒LMP1通过IκBα的磷酸化并降解激活核转录因子NF κB的活性 ,并且 ,LMP1诱导的NF κB活性能被IκBα的显性负性突变子完全抑制。IκBβ在此信号传导途径中无改变。LMP1表达前后IκBα蛋白总量维持恒定可能是由于NF κB的活化迅速启动了IκBα的重头合成这一自身调节环路所致。     

免疫-PCR法检测柯萨奇病毒B组抗原的实验研究

目的：建立免疫－PCR法,对分离培养和柯萨奇B组病毒（CoxB)毒株及临床可疑为CoxB感染的血清标本进行检测。方法：以间日疟原虫SSUrRNA基因为指示分子,采用生物系进行末端标记,利用酶联免疫吸附试验（ELISA）和PCR原理,建立免疫－PCR法,并对60份临床标本进行检测。结果：该方法具有较高敏感性和特异性,其敏感性是ELISA法的3000倍,也高出RT－PCR法10倍。结论：免疫－PCR法是检测CoxB抗原的敏感而特异的方法,为CoxB的临床早期快速鉴定和流行病学研究等提供了一种新的微量抗原检测手段。     

新的人抗HBsAg抗体Fab cDNA的克隆及序列分析

目的 从已构建的人抗－ＨＢsAg噬菌体抗体库中筛选出结合乙肝表面抗原（ＨＢsAg)的特异的人噬菌体抗体（Ｆab段）,并进行基础序列分析。方法 对噬菌体抗全库进行三轮“吸附－洗脱－扩增”的筛选,使特异性噬菌体抗体得到了富集,ＥＬＩＳＡ实验和ＥＬＩＳＡ竞争抑制实验鉴定出乙肝表面抗原的特异性抗体,同时对筛选出的克隆进行基因序列分析。结果 得到与乙肝表面抗原特异结合的抗体,并通过基因序列分析证明为抗乙肝ＨＢsAg的抗休天经地义人得到的抗惭肝ＨＢ－sAg的特异抗体为下一步表达纯化工作奠定了基础。