Use of TaqI digestion may lead to incorrect molecular diagnosis of congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Congenital adrenal hyperplasia (CAH) is a common autosomal recessive disorder mainly caused by defects in the steroid 21-hydroxylase (CYP21) gene. For reliable and accurate mutation detection in the CYP21 gene it is important to separate the CYP21 gene from the highly homologous CYP21P pseudogene. For this, several different strategies have been developed. In the analysis of the common eight nucleotide deletion at codon 110-112, a strategy using the TaqI restriction enzyme was first applied. In one family, the results showed discordance between parents and offspring. The use of microsatellite markers flanking the genuine CYP21 gene did not lead to a correct assignment. The problem was finally resolved by using differential PCR amplification for generating a CYP21-specific template. It was concluded that incomplete TaqI digestion, although not visible on an agarose gel, allowed the amplification of the CYP21P pseudogene, thus leading to a false positive diagnosis. Therefore, we recommend the use of direct gene-specific primers for the essential step in the molecular diagnosis of congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency.

Development of brain injury in mice by Angiostrongylus cantonensis infection is associated with the induction of transcription factor NF-kappaB, nuclear protooncogenes, and protein tyrosine phosphorylation

Eosinophilic meningitis or meningoencephalitis caused by Angiostrongylus cantonensis is endemic to the Pacific area of Asia, especially Taiwan, Thailand, and Japan. Although eosinophilia is an important clinical manifestation of A. cantonensis infection, the role of eosinophils in the progress of the infection remains to be elucidated. In this experiment, we showed that A. cantonensis-caused eosinoplia and inflammation might lead to the induction of NF-kappaB and protooncogene expression via activation of the tyrosine phosphorylation signal pathway. After mice were infected daily with 30 third-stage larvae of A. cantonensis by oral adminstration for 6 weeks, no significant differences PKC-alpha, MEK-1, ERK-2, JNK, and p38 protein expression were found between the control and infected mice. However, the protein tyrosine phosphorylation levels, NF-kappaB, and iNOS protein products were significantly increased by 3.5-, 3.3-, and 6.3-fold, respectively, after 3 weeks of A. cantonensis infection. The same pattern was found for c-Myc, c-Jun, and c-Fos proteins, which were elevated by 3.2-, 2.3-, and 3.4-fold, respectively, compared to control animals after 3 weeks. The expression potency of these proteins started increasing in week 1, reaching maximal induction in week 3, and then declining in week 5 after A. cantonensis infection. Another consistent result was noted in the pathological observations, including eosinophilia, leukocyte infiltration, granulomatous reactions, and time responses in brain tissues of infected mice. These data suggest that the development of brain injury by eosinophlia of A. cantonensis infection is associated with NF-kappaB and/or nuclear protooncogenes expression, which is activated by the tyrosine phosphorylation pathway.

Mutation analysis of the Bcl 10 gene in hepatocellular carcinoma

The Bcl 10 gene was recently discovered to be involved in the pathogenesis of lymphoma of mucosa-associated lymphoid tissue and several types of tumorous cell lines. We examined the mutation of Bcl 10 gene in 31 hepatocellular carcinomas along with their corresponding non-tumorous tissues by single strand conformation polymorphism (SSCP) and direct sequencing. The results showed that 11.3% chromosomes had codon 5 GCA to TCA mutation, 4.8% chromosomes had codon 8 CTC to CTG mutation, and 12.9% chromosomes had codon 213 GGA to GAA mutation. These mutations were found not only in the hepatoma tissues but also in paired non-cancerous tissues and the normal population. We suggest that these three changes are polymorphisms, and there is no relationship with the development of hepatocellular carcinoma.

Qualitative determination of urinary morphine by capillary zone electrophoresis and ion trap mass spectrometry

A rapid, sensitive method for the determination of morphine and amphetamine was developed using capillary zone electrophoresis coupled with electrospray interface (ESI), ion-trap tandem mass spectrometry (CE-ESI-MS2). Morphine and amphetamine were separated in 20 mM ammonium acetate buffer (pH 6.6) and detected by ion-trap mass detector in different analytical time segments (0-6.25 min for amphetamine and 6.25-12.0 min for morphine) in which the tune file for each compound was used separately. Molecular ions of morphine (m/z 286) and amphetamine (m/z 136) were detected at 5.77 and 6.83 min, respectively, while product ions of MS2 for each compound (m/z 229, 201 for morphine and m/z 119 for amphetamine) were detected almost exactly at the same time with their parent compounds. The limits of detection (LOD) for MS2 determination were 30 and 50 ng/mL for amphetamine and morphine, respectively, with an S/N ratio of 3. For more sensitive detection of morphine, the sample was injected for a longer time (i.e., 80 s) and hydrodynamically transported into a CE capillary for MS detection. Morphine and its product ion appear at 0.36 and 0.39 min on the ion chromatogram, respectively, with a five-fold increase of detection sensitivity (LOD, 10 ng/mL). The CE-MS system thus established was further applied for forensic urine samples screened as morphine-positive by fluorescence polarization immunoassay (FPIA). These results indicated the feasibility of CE-ESI-MS2 for confirmative testing of morphine in urine sample.

Analysis of the chimeric CYP21P/CYP21 gene in steroid 21-hydroxylase deficiency

BACKGROUND

A single nonfunctional chimeric gene with its 5' and 3' ends corresponding to CYP21P and CYP21, respectively, is caused by unequal gene crossover in the CYP21 genes during meiosis. The presence of the chimeric CYP21P/CYP21 molecule can not be detected by conventional PCR methods and therefore may be lost in PCR amplification. This leads to a false result and diagnostic discordance.

METHODS

We developed a rapid and direct method to detect a chimeric CYP21P/CYP21 gene that uses a 3'-specific primer for the CYP21 gene and two different 5' primers for both CYP21 and CYP21P to amplify the wild-type CYP21 and the chimeric CYP21P/CYP21 genes. A secondary PCR that can differentiate the chimeric from the wild-type gene was also performed. The PCR product was directly analyzed on agarose gel.

RESULTS

After careful titration, we found that earlier failure to detect the chimeric CYP21P/CYP21 gene could be caused by unequal concentrations of two independent alleles as the PCR template or by the lack of primers to amplify chimeric molecules. We successfully amplified the chimeric gene using our improved method.

CONCLUSIONS

The chimeric CYP21P/CYP21 is present in a large portion of congenital adrenal hyperplasia patients. By adding a CYP21P/CYP21-specific primer, we were able to amplify and detect both homozygous and heterozygous chimeric genes. Therefore, our new PCR-based assay is a more effective way to analyze congenital adrenal hyperplasia mutations.

Analysis of an SMN gene-like DNA fragment

Part of a survival motor neuron (SMN) gene-like DNA fragment has been identified. This DNA fragment was accidentally isolated from cDNA by RT-PCR using primers specific for the region between exon 3 and 6 of the SMN gene. This fragment was used as a probe to hybridize the mRNA from several tissues, but we have been unable to detect any transcript of this SMN-like gene in these tissues. Thus, we have inferred this SMN gene-like fragment was a genomic product contaminant that was amplified in the reaction. Sequencing analysis of this fragment, which contains several stop codons, revealed a 74.6% nucleotide homology with the SMN gene. From these results, we believe that this DNA fragment is not a mutated form of SMN gene. Rather, it is an SMN-like pseudogene, which is variably present even in normal individuals.

Rapid identification of the ABO genotypes by their single-stand conformation polymorphism

The ABO locus on chromosome 9 contains many more alleles than are currently used routinely in forensic science. The use of single-strand conformation polymorphism (SSCP) can separate sequence polymorphisms that differ by only one base. The SSCP process used allows for both single- and double-stranded polymerase chain reaction (PCR) products to be visualized. The six ABO genotypes can be differentiated by the allele-specific B and O SSCP patterns. The double-stranded DNA produced 'hybrid' bands due to heterozygous samples and allowed sequence diversity to be detected between alleles of heterozygotes. These 'hybrid' bands are valid markers to confirm genotypes of specimens.

Carrier analysis and prenatal diagnosis of congenital adrenal hyperplasia caused by 21-hydroxylase deficiency in Chinese

Congenital adrenal hyperplasia (CAH) is a common autosomal recessive disorder mainly caused by defects in the steroid 21-hydroxylase (CYP21) gene. We screened 1,000 healthy people, using a previously developed differential PCR method combined with single-strand conformation polymorphism and amplification-created restriction site methods for the carrier detection of the CYP21 gene deficiency. Our results indicated that the rate of occurrence of the heterozygous CAH carrier was about 12 in 1,000, with a gene frequency of 0.0060 and an incidence frequency of 1 in 28,000 in the Chinese population. In addition, 9 cases of CAH families were performed with prenatal diagnosis. Among them, 3 cases were diagnosed as the severe form, 4 cases carried the heterozygous mutation, and 2 were normal. This is the first report of carrier frequency analysis and prenatal diagnosis of 21-hydroxylase deficiency in Chinese.

Effect of die relief on the seating, fit and retention of cast gold crowns cemented on human teeth

Die relief, by means of a paint-on die spacing material, is the most common method of achieving sufficient space between metal castings and tooth surfaces for cement to flow during seating. Several studies have determined the influence of cementing variables on crowns made for metal and plastic test dies. This study assessed the influence of die relief upon the seating and retention of cast gold crowns constructed for natural human teeth. Standard full crown preparations were made for 10 matched pairs of extracted human third molars, one each of which had been relieved with die spacer of approximately 40 microns thickness. Crowns were made by the indirect technique and were cemented with zinc phosphate cement in a static/dynamic jig. Seating behaviour and vertical discrepancies were measured electronically. Tensile bond strengths were determined in a universal testing machine. Results showed that die relief reduced vertical seating discrepancy associated with cementation by up to 79 microns. Differences between paired relieved and unrelieved samples were significant (p < 0.05). There were no statistically significant differences in tensile bond between paired relieved and unrelieved crowns.

Molecular analysis of Duffy, Yt and Colton blood groups in Taiwanese, Filipinos and Thais

We used a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for DNA-based typing of Duffy, Yt and Colton blood groups in Taiwanese, Filipinos and Thais. A total of 200 Taiwanese, 115 Filipinos and 105 Thais were studied. In the Duffy blood group in Taiwanese, 180 cases (90%) were homozygote of Fya, 18 cases (9%) were double heterozygote of Fya and Fyb, and 2 cases (1%) were homozygote of Fyb. In Filipinos, 98 cases (85.2%) were homozygote of Fya, 16 cases (14.0%) were double heterozygote of Fya and Fyb and 1 case (0.8%) was homozygote of Fyb. In Thais, 87 cases (82.9%) were homozygote of Fya, 18 cases (17.1%) were double heterozygote of Fya and Fyb, and no case of Fyb was found. These results correlate well with serological phenotype. For the Yt blood group, only YT1 was found in Taiwanese. Among Filipinos, 114/115 (99.1%) was YT1/1 and 1/115 (0.9%) was YT1/2. In Thais, 103/105 (98.1%) was YT1/1 and 2/105 (1.9%) was YT1/2. For the Colton blood group, the results showed that there was only Coa allele in these three populations. Our results provide the first data of the Yt and Colton blood groups in these three populations.

Nitracrine N-oxides: effects of variations in the nature of the side chain N-oxide on hypoxia-selective cytotoxicity

The tertiary amine N-oxide (nitracrine-N-oxide, 1b) of the 1-nitroacridine nitracrine is a bis-bioreductive agent showing very high hypoxic selectivity (approximately 1000-fold) against tumour cells in culture, but only modest activity against the hypoxic subfraction of tumours in vivo. Because the hypoxic selectivity of 1b was considered to depend significantly on the rate of enzyme-mediated reduction of the N-oxide group, this paper reports the preparation and evaluation of a series of analogues in which the environment of this group was modified. Three analogues contained more weakly basic N-oxides, while two others had varying degrees of steric bulk around the N-oxide. In all but one case (an aromatic N-oxide), the N-oxides were much less cytotoxic (10- to 300-fold) than the corresponding tertiary amines towards AA8 Chinese hamster cells under aerobic conditions. Both the N-oxides and the corresponding amines were more cytotoxic to an ERCC-1 mutant defective in nucleotide excision repair, indicating that DNA alkylation was the cytotoxic event. However, there was no apparent correlation of these parameters with structure. All of the aliphatic N-oxides, with the exception of the aromatic N-oxide example, showed substantial (70- to 800-fold) hypoxic selectivity against AA8 cells in a clonogenic assay. While the weakly basic derivatives were the least selective, there was no apparent relationship between hypoxic selectivity and the steric environment of the N-oxide. Selectivity for hypoxic cells in culture is shown to depend on the hypoxic selectivity of the corresponding tertiary amine (reflecting O2-inhibitable reduction of the 1-nitro group) and the differential in aerobic toxicity between amine and N-oxide (a measure of the potential toxicity increase achievable by reducing the N-oxide). Four analogues whose structures fairly represented the range of steric and electronic modifications of the N-oxide site were evaluated against the hypoxic subfraction of cells in KHT tumours in vivo, but were inactive. These results suggest that either such modifications do not exert significant effects on N-oxide reduction, or that the rate of such reduction is not a factor limiting the in vivo activity of the parent analogue 1b.

Fracture toughness and durability of chemically or thermally tempered metal-ceramic porcelain

Thermocycling and water storage effects on fracture toughness (KIC) of chemically or thermally tempered metal-ceramic disks were investigated to evaluate the durability of tempering effects with regard to oral aqueous environment. Metal-ceramic disks (phi 10 mm x 2.0 mm) consisting of opaque porcelain (0.2 mm thick), body porcelain (1.3 mm) and Ni-Cr-Be alloy (0.5 mm) were prepared and the porcelain surfaces were polished with 1-micron diamond paste. The disks were subjected to ion exchange (potassium or rubidium) or thermal tempering treatments, then with the as-polished or further annealed disks, thermocycled for 8000, 15,000, and 22,000 cycles between 5 degrees C and 60 degrees C or stored in water at 37 degrees C for 33 days. After aging, KIC values of disks were determined by a Vickers indentation technique. Statistical analyses indicated that the KIC values of ion-exchanged and annealed disks were not significantly affected by the limited number of cycles and water storage, while the thermally tempered and untreated disks revealed a significant decrease in mean KIC from even 8000 cycles and after storage. However, there was no significant difference between thermocycling and water-storage effects on mean KIC of all surface treatment groups. Results indicate that chemical tempering (ion exchange) produced more durable residual stresses than does thermal tempering for metal-ceramic restorations. A low-thermal load only was unlikely to affect the apparent fracture toughness of porcelain.

NF-kappa B-dependent Fas ligand expression

Apoptosis of lymphocytes is triggered by different stimuli through the induced expression of Fas and Fas ligand (FasL). Using T cell activation-induced Fas/FasL expression as a model system, we observed a differential regulation of the induction of Fas and FasL. cAMP inhibited activation-induced apoptosis by an effective suppression of TCR-coupled FasL expres sion. In contrast, cAMP weakly interfered with activation-induced Fas expression, and the remaining Fas molecules on cAMP-treated T cells still mediated apoptosis. Among the major transcription elements on the FasL promoter, the activation of NF-kappaB, but not of NF-AT and AP-1, was suppressed by cAMP. The prominent role of NF-kappaB was further demonstrated by a better activation of the FasL promoter and an elevated expression of FasL induced by p65 (RelA) overexpression than those induced by AP-1 or NF-AT. Our results demonstrate the essential role of NF-kappaB for the expression of the death receptor ligand FasL, and suggest a direct link between NF-kappaB activation and the expression of FasL. NF-kappaB may be the common mediator in the induction of FasL through TCR activation and by various stress stimuli.

NF-kappaB-mediated up-regulation of Bcl-x and Bfl-1/A1 is required for CD40 survival signaling in B lymphocytes

Activation of CD40 is essential for thymus-dependent humoral immune responses and rescuing B cells from apoptosis. Many of the effects of CD40 are believed to be achieved through altered gene expression. In addition to Bcl-x, a known CD40-regulated antiapoptotic molecule, we identified a related antiapoptotic molecule, A1/Bfl-1, as a CD40-inducible gene. Inhibition of the NF-kappaB pathway by overexpression of a dominant-active inhibitor of NF-kappaB abolished CD40-induced up-regulation of both the Bfl-1 and Bcl-x genes and also eliminated the ability of CD40 to rescue Fas-induced cell death. Within the upstream promoter region of Bcl-x, a potential NF-kappaB-binding sequence was found to support NF-kappaB-dependent transcriptional activation. Furthermore, expression of physiological levels of Bcl-x protected B cells from Fas-mediated apoptosis in the absence of NF-kappaB signaling. Thus, our results suggest that CD40-mediated cell survival proceeds through NF-kappaB-dependent up-regulation of Bcl-2 family members.

Pediatric genitourinary tumors

Advances in our knowledge of pediatric genitourinary tumors are being made at a rapid pace at both the basic science and clinical levels. As the molecular mechanisms underlying these malignancies are being uncovered, treatment options are being modified to decrease morbidity and, ultimately, increase survival. This article reviews the recent literature on Wilms' tumor, rhabdomyosarcoma, and testicular tumors.

Neoadjuvant hormonal therapy in carcinoma of the prostate

The rising incidence of and mortality from prostate cancer has generated great interest in improving the results of current methods of treatment. It is well-established that large tumour volumes and positive surgical margins are correlated with higher rates of local failure and distant metastasis. Significant decreases in both tumour volume and the rates of positive surgical margins are seen with NHT. Follow-up data from one randomized trial of hormonal therapy before RT have shown significantly improved disease-free survival, but so far there has been no benefit in overall survival. However, the addition of adjuvant hormonal therapy has been reported to improve survival. The results suggest that neoadjuvant and adjuvant hormonal therapy may be a viable option in men with locally advanced prostate cancer in whom cure is probably impossible, but disease progression can potentially be slowed. What remains to be determined is whether hormonal therapy alone can produce the same results. For younger men with clinically localized prostate cancer, radical prostatectomy is increasingly the treatment of choice. Prospective randomized trials of NHT have produced impressive statistics for decreasing the incidence of positive surgical margins, but the potential to down-stage tumours remains controversial. Follow-up serum PSA measurements have thus far shown no benefit from neoadjuvant therapy. The possibility that patients who fail biochemically, whether they are from the pretreated or control group, may simply represent a subgroup with aggressive tumours that may not respond to androgen withdrawal, has yet to be proved. As more follow-up data are analysed within the next several years, there must be a clear survival advantage if NHT is to be offered as a treatment option. Despite the potential of neoadjuvant therapy, the use of androgen withdrawal before definitive surgical treatment should be limited to clinical trials until a clearer picture emerges. Some may argue that although there is no evidence of a true advantage for NHT, neither is there evidence of harm. However, it must be recognized that androgen withdrawal therapy has side-effects and adds significantly to the overall cost of treatment. Furthermore, NHT delays definitive treatment; clearly, this can be a source of anxiety for the patient and the impact on survival is unknown. Currently, the rates of pathologically organ-confined disease are high in some subsets of patients (e.g. low-stage, low-grade and low PSA) so that NHT is unlikely to have great additional benefit. Although the influence of hormones on prostate growth has been known for many decades, we are only now elucidating the biological mechanisms of hormonal therapy. Although androgen ablation therapy has been used in men with metastatic prostate cancer for more than 50 years, further research at the cellular and molecular level is essential if we are to refine treatment modalities for both localized and advanced disease. Furthermore, until we have more follow-up data from randomized clinical trials of NHT, it cannot be considered part of the standard treatment for carcinoma of the prostate. There are still too many unknown factors; only time will tell if the initial promise of NHT will be fulfilled.

Specificities of CD40 signaling: involvement of TRAF2 in CD40-induced NF-kappaB activation and intercellular adhesion molecule-1 up-regulation

Several tumor necrosis factor receptor-associated factor (TRAF) family proteins including TRAF2, TRAF3, TRAF5, and TRAF6, as well as Jak3, have been implicated as potential mediators of CD40 signaling. An extensive in vitro binding study indicated that TRAF2 and TRAF3 bind to the CD40 cytoplasmic tail (CD40ct) with much higher affinity than TRAF5 and TRAF6 and that TRAF2 and TRAF3 bind to different residues of the CD40ct. Using CD40 mutants incapable of binding TRAF2, TRAF3, or Jak3, we found that the TRAF2-binding site of the CD40ct is critical for NF-kappaB and stress-activated protein kinase activation, as well as the up-regulation of the intercellular adhesion molecule-1 (ICAM-1) gene, whereas binding of TRAF3 and Jak3 is dispensable for all of these functions. Overexpression of a dominantly active IkappaBalpha strongly inhibited CD40-induced NF-kappaB activation, ICAM-1 promoter activity, and cell-surface ICAM-1 up-regulation. These studies suggest a potential signal transduction pathway from the CD40 receptor to the transcriptional activation of the ICAM-1 gene.

Vezf1: A Zn finger transcription factor restricted to endothelial cells and their precursors

Using retroviral entrapment vectors, we identified a novel mouse gene whose expression is restricted to vascular endothelial cells and their precursors in the yolk sac blood islands. A 3.68-kb cDNA corresponding to the endogenous transcript was isolated using genomic DNA flanking the entrapment vector insertion as a probe. We have named this gene Vezf1 for vascular endothelial zinc finger 1. Vezf1 encodes a protein with a predicted molecular mass of 56 kDa and that contains six putative zinc finger domains and shows high homology to a previously identified human gene, DB1, that is believed to be involved in regulating expression of cytokine genes such as interleukin-3. In situ hybridization analysis revealed the onset of expression in advanced primitive streak-stage embryos being located in the extraembryonic mesodermal component of the visceral yolk sac and in the anteriormost mesoderm of the embryo proper. During head-fold and somite stages, expression was restricted to vascular endothelial cells that arise during both vasculogenesis and angiogenesis. Vezf1-related sequences were found to be highly conserved among higher vertebrate species that have acquired extraembryonic yolk sac membranes during evolution. The Vezf1 locus mapped to the proximal part of mouse chromosome 2, a region which has homology to human chromosome 9q. Vezf1 expression correlates temporally and spatially with the early differentiation of angioblasts into the endothelial cell lineage and the proliferation of endothelial cells of the embryonic vascular system. Thus, Vezf1 may play an important role in the endothelial lineage determination and may have an additional role during later stages of embryonic vasculogenesis and angiogenesis.

Development of calcium phosphate cement for rapid crystallization to apatite

The purpose of this study was to develop an alpha-tricalcium phosphate (alpha-TCP) cement which transforms to hydroxyapatite (HAP) in a relatively short period. We used calcium and phosphate solutions as the liquid phase for the alpha-TCP cement. The alpha-TCP powder was first mixed with CaCl2 solution, and then mixed with NaH2PO4 or Na2HPO3 solution for a total powder/liquid ratio of 1.8. The setting time became shorter with the increase in the concentration of calcium and phosphate solutions, reaching 5 min, whereas the setting time was longer than 30 min when distilled water was used as the liquid phase. X-ray diffraction analysis revealed that the cement was mostly transformed to HAP within 24 h when kept in an incubator. We concluded that alpha-TCP should be mixed with calcium and phosphate solutions since this results in a moderate setting time and fast transformation to HAP even if the method of mixing becomes a little complex.

Identification of four novel mutations in the CYP21 gene in congenital adrenal hyperplasia in the Chinese

Congenital adrenal hyperplasia (CAH) is a common autosomal recessive disorder mainly caused by defects in the steroid 21-hydroxylase (CYP21) gene. We have analyzed CYP21 gene sequences in 65 CAH families in Taiwan. All ten exons of the CYP21 gene were analyzed by differential polymerase chain reaction followed by single-strand conformation polymorphism electrophoresis and the amplification-created restriction site method. About 95% (123 chromosomes) contain mutations due to conversion of DNA sequences into its neighboring homologous pseudogene, CYP21P. Four novel mutations representing 5% of the total chromosomes have also been identified. The mutations were confirmed by sequencing an aberrant DNA fragment. These four mutations included a base change of the splicing donor site at intron 2 from GT to AT, a base substitution of C to T at codon 316, deletion of ten bases (TCCAGCTCCC) at codons 330-333 of exon 8, and duplication of 16 bases (CCTGGATGACACGGTC) at codons 393-397 of exon 9. The loss of the splicing donor site at intron 2 and the premature stop at codon 316 may result in aberrant splicing to reduce enzyme activity and a truncated protein with no enzyme activity, respectively. Likewise, both the duplication and the deletion forms create a frameshift and premature stop during translation. The resulting proteins lack the heme-binding domain and hence are expected to lose enzymatic activity. Since these mutations are not found in the neighboring CYP21P pseudogene, gene conversion should not be the cause of these novel mutations.