Estimation of the age at onset in spinocerebellar ataxia type 2 Cuban patients by survival analysis

Almaguer‐Mederosa LE, Falcón NS, Almira YR, Zaldivar YG, Almarales DC, Góngora EM, Herrera MP, Batallán KE, Armiñán RR, Manresa MV, Cruz GS, Laffita‐Mesa J, Cyuz TM, Chang V, Auburger G, Gispert S, Pérez LV. Estimation of the age at onset in spinocerebellar ataxia type 2 Cuban patients by survival analysis. Previous studies have investigated the close association that exists between CAG repeat number and the age at onset in SCA2 = spinocerebellar ataxia type 2. These studies have focused on affected individuals. To further characterize this association and estimate the risk of a carrier developing SCA2 at a particular age as a function of a specific CAG repeat size, we have analyzed a large group of 924 individuals, including 394 presymptomatic and 530 affected individuals with a CAG repeat length of 32–79 units. Using a Kaplan–Meier survival analysis, we obtained cumulative probability curves for disease manifestation at a particular age for each CAG repeat length in the 34–45 range. These curves were significantly different (p < 0.001) and showed small overlap. All these information may be very valuable in predictive‐testing programs, in the planning of studies for the identification of other genetic and environmental factors as modifiers of age at onset, and in the design of clinical trials for people at enlarged risk for SCA2.     

Frameshift mutations in salmonella induced by the extracts of medicinal herbs Lannea edulis (sond.) engl. and Monotes glaber sprague

Lannea edulis an(d Monotes glaber have been prescribed for various affectations in the traditional medical practice of Zimbabwe and other parts of Africa. Mutagenicity testing using Salmonella typhimurium strains TA97a, TA98, and TA100, indicated that the aqueous extracts of these plants induced frameshift mutations in Salmonella. The extract of L. edulis displayed marginal mutagenicity in strain TA97a while that of M. glaber showed a significant dose-dependent mutagenicity in both strains TA97a and TA98. There was no mutagenic effect observed in strain TA100. Two other plant extracts, those of Lannea discolor and Dolichos kilimandscharicus, were nonmutagenic in all three strains. © 1995 Wiley-Liss, Inc.     

Controlled comparison of percutaneous and microsurgical sperm retrieval in men with obstructive azoospermia

A controlled comparison of the efficacy and reliability of sperm retrieval by testicular fine needle aspiration (TFNA), percutaneous testicular needle biopsy (PercBiopsy) and microsurgical epididymal sperm aspiration (MESA) was performed in nine patients with obstructive azoospermia. During a planned MESA procedure, sperm retrieval was attempted on the same testis with TFNA and PercBiopsy. Spermatozoa were obtained from all patients using MESA and PercBiopsy. Spermatozoa were retrieved using TFNA from 6/9 (67%) men. The mean number of epididymal spermatozoa retrieved with MESA (15 x 106) was significantly higher (P = 0.003) than that retrieved percutaneously from the testis. The mean number of spermatozoa obtained by PercBiopsy was 0.116 x 10(6) while TFNA recovered 0.014 x 106 spermatozoa (P = 0.025). MESA is the optimal choice to retrieve the greatest number of spermatozoa with highest motility for assisted reproduction and subsequent cryopreservation. However, percutaneous testicular retrieval does not require microsurgical expertise and is less invasive. Our results suggest that the optimal percutaneous procedure for sperm retrieval from the testis involves percutaneous testicular needle biopsy with an automatic biopsy gun.      

Basaloid squamous cell carcinoma of the esophagus: an immunohistochemical study of 8 cases

Objective To explore the biological features of basaloid squamous cell carcinoma (BSC) of the esophagus.Methods Cytokeratins (CK4, CK18 and CK19), epithelial membrane antigen (EMA), carcino e mbryo antigen (CEA), α-smooth muscle antigen (α-SMA), S-100, laminin (LN), collagen Ⅳ (Col-Ⅳ), neural-specific enolase (NSE), proliferating cell nuclea r antigen (PCNA) and p53 antibodies were used to detect the corresponding antigen expression in 8 cases of BSC with ABC immunohistochemical methods.Results Two kinds of BSC cell components have different responses to the above antibodies. For basaloid cells (BCs), 7 cases were positive for CK19, and were negative for the other 4 epithelial antibodies CK4, CK18, CEA and EMA. BCs of 4 cases were positive to the muscular antibodies α-SMA and S-100, and the hyaline degeneration in the tumor nests was positive for LN and Col-Ⅳ. BCs h ad a high index of PCNA, with an average level of 54%. For squamous cells (SC s), 7 cases were positive for the epithelial antigen CK4, CEA and EMA, but were negative for CK19, α-SMA and S-100. The index of PCNA of SC was low, with a n average level of 25%.Conclusion BSC of the esophagus is a high-malignancy tumor which is of multi-oriented di fferentiation. BCs represent basal cells which have the tendency of myoepitheli al differentiation and have strong proliferation ability, whereas SCs represent typical squamous cell differentiation.     

Accurate and independent measurement of volume and hemoglobin concentration of individual red cells by laser light scattering

Cell volume (MCV) and hemoglobin concentration (MCHC) are the red cell indices used to characterize the blood of patients with anemia. Since the introduction of flow cytometric methods for the measurement of these indices, it has generally been assumed that the values derived by these instruments are accurate. However, it has recently been shown that a number of cellular factors, including alterations in cellular deformability, can lead to inaccurate measurement of cell volume by these automated instruments. Because cell hemoglobin concentration and hematocrit are computed from the measured values of cell volume, accuracy of these indices is also compromised by inaccurate determination of cell volume. A recently developed experimental flow cytometric method based on laser light scattering, which can independently measure volume and hemoglobin concentration, has been used in the present study to measure MCV and MCHC of density- fractionated normal and sickle red cells, hydrated and dehydrated normal red cells, and various pathologic cells. We found that the new method accurately measures both volume and hemoglobin concentrations over a wide range of MCV (30 to 120 fL) and MCHC (27 to 45 g/dL) values. This is in contrast to currently available methods in which hemoglobin concentration values are accurately measured over a more limited range (27 to 35 g/dL). In addition, as the experimental method independently measures volume and hemoglobin concentration of individual red cells, it allowed us to generate histograms of volume and hemoglobin concentration distribution and derive coefficient of variation for volume distribution and standard deviation of hemoglobin concentration distribution. We have been able to document that volume and hemoglobin concentration distributions can vary independently of each other in pathologic red cell samples.     

High frequency of HLA-A*0103 allele in a Somali population

We report the existence of class I HLA allele A*0103 in an ethnic group (Somali) where this allele has not been reported. This allele was discovered in a study to examine the relationship between HLA alleles and humoral antibody response to measles vaccine among recent immigrants from Somalia to Olmsted County, Minnesota. We initially used polymerase chain reaction-sequence-specific primers (PCR-SSP) to carry out HLA class I typing. Based on PCR-SSP, 55 subjects were assigned the allele HLA-A*0101. Following direct DNA sequencing of the PCR products, 37 of the 55 subjects (67.3%) that were initially assigned the A*0101 allele were found to actually be A*0103. Our data are significant because it demonstrates that many of the previously typed A*0101 individuals are actually A*0103 as the SSP or sequence-specific oligonucleotide probes method cannot distinguish between the two alleles. Lastly, this is the first identification of this allele in the homozygous state.     

Inhibitory effect of black tea on the growth of established skin tumors in mice: effects on tumor size, apoptosis, mitosis and bromodeoxyuridine incorporation into DNA

Female CD-1 mice were initiated with a single topical application of 7,12-dimethylbenz[a]anthracene and promoted with 12-O- tetradecanoylphorbol-13-acetate. Mice with established papillomas were then treated with black tea or decaffeinated black tea (approximately 4 mg tea solids/ml) as the sole source of drinking fluid for 11-15 weeks. In four separate experiments, oral administration of black tea inhibited the growth of papillomas (increase in tumor volume/mouse) by an average of 35%, 37%, 41% and 48%, respectively. Studies with decaffeinated black tea gave inconsistent results. In one experiment, administration of decaffeinated black tea inhibited papilloma growth (increase in tumor volume/mouse) by 27%, but in two additional experiments papilloma growth was stimulated by 14% and 193%, respectively. In a separate experiment, skin tumors were generated by treating SKH-1 female mice with ultraviolet B light (UVB; 30 mJ/cm2) twice weekly for 22 weeks, after which UVB administration was stopped. Tumors were allowed to develop during the following 13 weeks, and tumor- bearing mice were then treated with black tea (6 mg/ml tea solids) as the drinking fluid for 11 weeks. In this experiment, tumor growth (increase in tumor volume/mouse) was inhibited by 70%. Histological examination revealed that tea-treated mice had a 58% decrease in the number of nonmalignant tumors (primarily keratoacanthomas)/mouse and a 54% decrease in the number of squamous cell carcinomas/mouse. In addition, administration of black tea decreased the volume per tumor by 60% for nonmalignant tumors and by 84% for carcinomas. Mechanistic studies with tumors from these mice revealed that administration of black tea decreased the bromodeoxyuridine labeling index in squamous cell papillomas, keratoacanthomas and squamous cell carcinomas by 56%, 45% and 35%, respectively, and the apoptosis index was increased by 44%, 100% and 95%, respectively. Administration of black tea decreased the mitotic index in keratoacanthomas and squamous cell carcinomas by 42% and 16%, respectively. The results indicate that oral administration of black tea to tumor-bearing mice inhibited proliferation and enhanced apoptosis in nonmalignant and malignant skin tumors.      

Effect of green tea on p53 mutation distribution in ultraviolet B radiation-induced mouse skin tumors

In the present study, administration of green tea to SKH-1 mice, via the drinking fluid, was found to significantly reduce the incidence and volume of ultraviolet B (UVB) radiation-induced skin tumors. Thirty-six skin tumors induced by UVB and 32 skin tumors induced by UVB, in mice treated with green tea in their drinking water, were collected and examined for the presence of mutations in the p53 gene. Polymerase chain reaction products from p53 exons 5-8 were screened by single- strand conformation polymorphism and direct sequence analyses. Eight of 36 UVB-induced tumors contained nine p53 mutations, with four in exon 5 and five in exon 8. In contrast, nine of 32 UVB-induced tumors in mice treated with green tea contained 11 p53 mutations, with two in exon 5, five in exon 6 and four in exon 8. All of the p53 mutations occurred at dipyrimidine sequences. These results were further corroborated by p53 immunohistochemistry. The most frequent mutations were C-->T or T-->C transitions, which are consistent with the genetic alterations caused by UVB exposure. Interestingly, mutations found in exon 6 of the p53 gene occurred only in tumors from the UVB/green tea group. Thus, the tumors observed in UVB/green-tea-treated mice have a different exon distribution of p53 mutations than tumors obtained from mice treated with UVB alone.      

Survivin基因在人胎儿血中的表达

目的:观察Survivin基因在人胎儿血中的表达及其意义。方法:实验于2003-10/2004-03在广西医科大学第一附属医院血液科完成。①实验材料:50份胎儿血、40份足月脐带血分别取自广西民族医院及南宁第二人民医院妇产科和本院妇产科,产妇均知情同意,并经医院伦理委员会批准。35份成人外周血为无血液系统疾患的健康献血者。②实验方法:无菌操作条件下取EDTA抗凝骨髓液4mL,常规分离单个核细胞,洗涤后制备合适密度备用。采用RT-PCR技术对50份孕龄为18～32周人胎儿血、40份足月脐带血和35份成人外周血Survivin基因m RNA表达水平进行检测。结果:①Survivin基因在人胎儿血、脐带血及成人外周血表达阳性率的比较:人胎儿血Survivin基因mRNA表达阳性率高于脐血组,差异有显著性意义(68.0%,47.5%,P<0.05)。②Survivin基因在人胎儿血及脐带血中表达水平的比较:人胎儿血Survivin基因mRNA表达水平高于脐带血,差异有显著性意义(0.575±0.276,0.444±0.626,P<0.05)。③Survivin基因表达水平与孕龄的关系:Survivin基因mRNA表达水平随着孕龄增加有下降趋势,对Survivin基因mRNA表达水平与孕龄的相关性进行直线相关分析,结果显示两者之间存在负相关(r=-0.373,P=0.030)。结论:①Survivin基因在人胎儿血及脐带血中均有表达,Survivin基因在人胎儿血中表达水平高于脐带血,在成人外周血中检测不到Survivin基因表达。②随着孕龄增加,人胎儿血中Survivin基因表达水平随之下降。③Survivin基因可能在人胎儿发育过程中起一定作用,具体机制还需进一步研究探讨。