Spectrum of MECP2 mutations in Rett syndrome

Mutations in the methyl-CpG-binding protein 2 gene (MECP2) are identified in the majority of females with Rett syndrome (RTT), an X-linked dominant neurodevelopmental disorder. We searched for mutations by sequencing the MECP2 coding region in 45 sporadic cases (35 with classic RTT, eight with variant forms and two males) and in seven families with two or more affected females. Following our previous report of mutations in two families and eight sporadic cases, we here present 18 additional mutations. We found 13 single nucleotide substitutions, all of which are C-->T transitions at CpG hot spots. Frameshift mutations, leading to premature termination of translation, include two single guanine (G) nucleotide deletions from a stretch of contiguous Gs, a novel four nucleotide deletion, a novel 32 nucleotide deletion in the C-terminal domain and a novel complex duplication/deletion rearrangement in the same region. When X-chromosome inactivation patterns were compared in 16 MECP2 mutation-positive and 23 mutation-negative samples, no significant differences were observed. The mutational spectrum in our subject population is similar to studies from around the world. Of over 300 MECP2 mutations reported, two-thirds are truncating mutations and one-third are missense mutations, mostly in the methyl-binding domain. Nearly 70% of all identified mutations are C-->T transitions at one of eight CpG hot spots, and about 10% are intragenic deletions or complex rearrangements that lead to frameshifts in the C-terminal region. The rate of mutation detection in the MECP2 coding region ranges from 70 to 85% in clinically diagnosed RTT and is much lower in diagnostic variants.

[A preliminary study of the combination of noninvasive parameters in the diagnosis of liver fibrosis]

OBJECTIVE

To explore the combination of noninvasive parameters and its significance in the diagnosis of liver fibrosis.

METHODS

Liver biopsy was performed on 200 patients with chronic liver diseases, and the biochemical parameters, serum fibrotic markers, and B ultrasound, CT, and MRI were detected in the corresponding period. Then, by the regression, we obtained the combination of the noninvasive parameters and evaluated the significance in the diagnosis of liver fibrosis.

RESULTS

Three combinations have been obtained. The parameters in the first combination which was used to differentiate fibrosis and no fibrosis(S0 vs S1+S2+S3+S4) were the parameter of blood flow of portal vein per minute by B ultrasonography, age, the maximum oblique line of right liver by B ultrasound, the wave expression of the surface of liver by CT/MRI and GGT. The parameters in the second combination which was used to evaluated the degree of fibrosis(S1+S2 vs S3+S4) were HA, A/G and the longest length of spleen by B ultrasound. The third combination which was used to distinguish fibrosis with cirrhosis (S1+S2+S3 vs S4) was composed by HA, the little cyst-like change near the intrahepatic duct, thickness of liver capsule by B ultrasound, age and the index of symptoms. All the three combinations were sensitive, specific, and accurate.

CONCLUSIONS

The combinations of noninvasive parameters is more valuable than single parameter in the diagnosis of liver fibrosis.

MECP2 truncating mutations cause histone H4 hyperacetylation in Rett syndrome

Rett syndrome (RTT) is a mostly sporadic disorder of developmental regression, with loss of speech and purposeful hand use, microcephaly and seizures. It affects 1 in 10 000-15 000 females. RTT is caused by mutations in the MECP2 gene, which is located in Xq28 and subject to X inactivation. MECP2 encodes a methyl-CpG-binding protein that binds to 5-methyl-cytosine in DNA through its methyl-binding domain. Recruitment of a transcriptional silencing complex through MeCP2's transcriptional repression domain results in histone deacetylation and chromatin condensation. To study the effects of two common truncating RTT mutations (R168X and 803delG), we examined mutant MeCP2 expression and global histone acetylation levels in clonal cell cultures from a female RTT patient with the mutant R168X allele on the active X chromosome, as well as in cells from a male hemizygous for the frameshift mutation 803delG (V288X). Both mutant alleles generated stable RNA transcripts, but no intact MeCP2 protein was detected with an antibody against the C-terminal region of MeCP2. Western blots with antibodies against acetylated histones H3 and H4 revealed that H4, but not H3, was hyperacetylated. By using antibodies against individual acetylated lysine residues, the observed H4 hyperacetylation was attributed to increased acetylation of lysine 16. Therefore, expression of endogenous truncating MECP2 alleles, in the absence of wild-type MeCP2 protein, is specifically associated with an increase in the mono-acetylated histone isoform H4K16. This observed effect may result in over-expression of MeCP2 target genes and, thus, play a role in the pathogenesis of RTT.

[Analysis of a case of balanced chromosome translocation and phenotypic abnormality by fluorescence in situ hybridization]

OBJECTIVE

To delineate the chromosome structural aberration in a case of chromosome translocation by fluorescence in situ hybridization(FISH) technique and precisely identify the breakpoints.

METHODS

The whole chromosome point 5(wcp5) and locus- specific probes derived from yeast artificial chromosomes(YACs) mapping the nearby region of breakpoints were used to delineate the translocation t(5;10) found by high resolution G-banding examination in a case with congenital abnormality.

RESULTS

A balanced translocation was confirmed and the breakpoints were located in the 1.5 Mb area on chromosome 5 and within the approximately 3 Mb interval on chromosome 10.

CONCLUSION

The phenotypic abnormality might result from the disruption of disease-associated gene(s) or microrearrangement(s) on the site of breakpoint(s).

Transcriptional mechanisms of bone morphogenetic protein-induced osteoprotegrin gene expression

Osteoprotegerin (OPG), an osteoblast-secreted decoy receptor, specifically binds to osteoclast differentiation factor and inhibits osteoclast maturation. Members of the transforming growth factor-beta superfamily including bone morphogenetic proteins (BMPs) stimulate OPG mRNA expression. In this study, we have characterized the transcription mechanism of BMP-induced OPG gene expression. Transfection of Smad1 and a constitutively active BMP type IA receptor ALK3 (Q233) stimulated the OPG promoter. Deletion analysis of the OPG promoter identified two Hoxc-8 binding sites that respond to BMP stimulation. Glutathione S-transferase-Hoxc-8 protein binds to these two Hox sites specifically. Consistent with the transfection results of the native promoter, ALK3 or Smad1 linker region, which interacts with Hoxc-8, stimulated the activation of the reporter construct with the two Hox sites. Overexpression of Hoxc-8 inhibited the induced promoter activity. When the two Hox binding sites were mutated, ALK3 or Smad1 linker region no longer activated the transcription. Importantly, Smad1 linker region induced both OPG promoter activity and endogenous OPG protein expression in 2T3 osteoblastic cells. The medium from cells transfected with Smad1 linker region expression plasmid effectively inhibited osteoclastogenesis. Collectively, our data indicate that Hox sites mediate both OPG promoter construct activity and endogenous OPG gene expression in response to BMP stimulation.

Strain imaging and elasticity reconstruction of arteries based on intravascular ultrasound video images

Based on intravascular ultrasound (IVUS) video images, a novel motion estimation method combining the genetic algorithm-based optical flow method and a step-by-step and sum strategy has been developed to estimate the displacement and strain distributions on the scan cross sections of the arteries. And then, real elasticity distributions were reconstructed under the conditions of small and large deformation. Experimental results of in vitro porcine arteries demonstrated the feasibility of the method. This investigation may have potentials to provide new technological means for monitoring and evaluating percutaneous transluminal coronary angioplasty procedure, especially, for the end users of IVUSpercimaging equipment.

In situ RT-PCR detection of inducible nitric oxide synthetase gene expression in lung during endotoxemia in rabbits

OBJECTIVE

To detect the location of inducible nitric oxide synthetase (iNOS) protein and mRNA in lung during endotoxemia in rabbits.

METHODS

Northern blotting was performed before, 1 hour and 5 hours after the intravenous administration of lipopolysaccharide (LPS) in rabbits. Immunohistochemical analysis (IA), in situ hybridization and in situ reverse transcription-polymerase chain reaction (in situ RT-PCR) were also performed in lung sections.

RESULTS

iNOS mRNA expression was found using Northern blotting in lung 5 hours after LPS injection, while it was not found in control. The positive stain was found only in macrophages in lung 5 hours after LPS injection by standard hybridization and IA; while by in situ RT-PCR, the amplification products were found in macrophages, airway epithelial cells, vascular endothelial cells, smooth muscle cells and leukocytes, in addition to macrophages distributed abundantly throughout the lung. The signal was absent in control or samples.

CONCLUSIONS

Using an in situ RT-PCR technique, iNOS expression was not only observed in macrophages but also in many other kinds of cells in lung during endotoxemia in rabbits. This suggests that in situ RT-PCR is much more sensitive than in situ hybridization, and can be used to examine genes with low expression.

[Clinical application of 3D reconstruction in maxillofacial fractures]

OBJECTIVE

To study the value of 3D reconstructive technique in midfacial fractures,especially its significance in preoperative diagnosis and operation planning of complicated,multiple fractures in midface.

METHODS

To preoperatively scan and reconstruct 47 fracture patients with spiral CT.

RESULTS

38 cases received operation which confirmed the preoperative diagnosis of 3D CT. The conservationed treatment was applied to other 9 patients.

CONCLUSION

The 3D reconstruction can reveal the complicated fractures in midface as approximate model, and benefit the selection of the most suitable plan before operation.

Inhibitory activity of flavonoids and tannins against HIV-1 protease

Twenty-nine flavonoids and six hydrolyzable tannins were studied for their inhibitory activity against human immunodeficiency virus (HIV)-1 protease using fluorescence and HPLC assays. Among the flavonoids, flavones, flavanones, flavonols, catechols and chalcones, the flavonols were the most active category while flavanones and catechols displayed low activity. Quercetin was the most potent inhibitor of the target enzyme with an IC50 value of 58.8 microM, while butein and luteolin showed moderate activity. Of the hydrolyzable tannins tested, three ellagitannins which contain a hexahydroxvdiphenoyl (HHDP) unit linked to the O-3 and 0-6 positions of the sugar, were found to strongly inhibit HIV-1 protease. The IC50 values of corilagin and repandusinic acid on HIV-1 protease were 20.7 and 12.5 microM, respectively.

Evaluation of evaporative light-scattering detector for combinatorial library quantitation by reversed phase HPLC

A quantitation study using reversed phase HPLC with UV and evaporative light-scattering detector (ELSD) was conducted on 90 library standards selected from 15 small molecule combinatorial libraries (six standards from each library). This study assessed the quantitation errors using a single calibration curve for rapid purity analysis of combinatorial libraries. The average quantitation error of six standards from one library at 200 microM by UV was 13. 4%, 20.6%, and 60.3%, at 214, 220, and 254 nm, respectively. By ELSD, the average quantitation error of these six standards at 200 micro was only 7.7%. Applying this ELSD calibration curve to 84 standards from 14 structurally diverse libraries, an average quantitation error of 16.4% was obtained. The average quantitation error of all 90 standards from 15 libraries using 15 calibration curves was 18.5%.

Rett syndrome is caused by mutations in X-linked MECP2, encoding methyl-CpG-binding protein 2

Rett syndrome (RTT, MIM 312750) is a progressive neurodevelopmental disorder and one of the most common causes of mental retardation in females, with an incidence of 1 in 10,000-15,000 (ref. 2). Patients with classic RTT appear to develop normally until 6-18 months of age, then gradually lose speech and purposeful hand use, and develop microcephaly, seizures, autism, ataxia, intermittent hyperventilation and stereotypic hand movements. After initial regression, the condition stabilizes and patients usually survive into adulthood. As RTT occurs almost exclusively in females, it has been proposed that RTT is caused by an X-linked dominant mutation with lethality in hemizygous males. Previous exclusion mapping studies using RTT families mapped the locus to Xq28 (refs 6,9,10,11). Using a systematic gene screening approach, we have identified mutations in the gene (MECP2 ) encoding X-linked methyl-CpG-binding protein 2 (MeCP2) as the cause of some cases of RTT. MeCP2 selectively binds CpG dinucleotides in the mammalian genome and mediates transcriptional repression through interaction with histone deacetylase and the corepressor SIN3A (refs 12,13). In 5 of 21 sporadic patients, we found 3 de novo missense mutations in the region encoding the highly conserved methyl-binding domain (MBD) as well as a de novo frameshift and a de novo nonsense mutation, both of which disrupt the transcription repression domain (TRD). In two affected half-sisters of a RTT family, we found segregation of an additional missense mutation not detected in their obligate carrier mother. This suggests that the mother is a germline mosaic for this mutation. Our study reports the first disease-causing mutations in RTT and points to abnormal epigenetic regulation as the mechanism underlying the pathogenesis of RTT.

In vivo hemodynamic evaluation based on transverse Doppler measurements of blood velocities and vessel diameter

We have developed a method for simultaneously measuring the blood flow velocity distributions along a line perpendicular to the vessel wall and the instantaneous diameter of the common carotid artery. Thus, the wall shear rates and shear rate distribution across the arterial lumen could be computed accurately. In this method, transverse Doppler technique is combined with ultrasonic A echo-mode, using only one single crystal transducer. In order to satisfy the requirements of high spatial and velocity resolutions, especially extending to a very low velocity range in the case of low signal-to-noise ratio, a combination scheme of 10-MHz operating frequency, sample volume tracking, 12-bit A/D, 512-point fast Fourier transform with 5-kHz sample rate, spectrum average, variable threshold for bandwidth estimation, smoothing of velocity curves, and hardware was carefully designed. The velocity distribution measurements based on transverse Doppler spectrums were also validated under the steady flow conditions using a flow loop system. Results from this study show this ultrasonic system to be capable of measuring the shear rates at wall accurately and shear rate distributions across the common carotid arterial lumen.

Suppression of tumorigenicity in human ovarian cancer cell lines is controlled by a 2 cM fragment in chromosomal region 6q24-q25

Multiple distinct regions of chromosome 6 are frequently affected by losses of heterozygosity in primary human ovarian carcinomas. We introduced a normal human chromosome 6 into HEY and SKOV-3 ovarian carcinoma cell lines using microcell-mediated chromosome transfer techniques to further investigate the role of this chromosome in ovarian tumorigenesis. The exogenous chromosome was stably propagated in the recipient cells based on fluorescence in situ hybridization (FISH) analyses with a chromosome 6 painting probe. The tumorigenicity of HEY and SKOV-3 cells was completely suppressed after transfer of chromosome 6, but not after transfer of a chromosome 11q13-qter fragment used as control. Using 46 polymorphic microsatellite markers, the region bounded by D6S1649 and D6S1564 was found to be commonly deleted in HEY: chromosome 6 tumorigenic revertant clones. The boundaries of the commonly deleted region could be further narrowed down to a 2 cM (based on the Whitehead genetic map) or 0.36 megabase (based on gdb mapping data) region between D6S1637 and D6S1564 after transferring the exogenous chromosome from revertants into mouse L cells and performing allelic deletion mapping studies against this mouse background. We conclude that this region contains a tumor suppressor gene important for the control of ovarian tumor development.

Variant antibody identification by peptide mapping

During development of CGP56901, a monoclonal antibody (MAb) specific for a unique epitope on human IgE, the protein A-purified IgG from one of the candidate production cell lines, showed an additional minor heavy chain (H-chain) band with a molecular weight slightly lower than that of the principal H-chain band on SDS-PAGE. The N-terminal amino acid sequence of this minor H-chain species indicated that at least the first 30 amino acids were identical to those of the antibody light-chain (L-chain) variable domain. More detailed studies using peptide mapping and amino acid sequencing analysis confirmed a crossover event between the V genes of the antibody. The position is between Arg108 of the L chain and Ala124 of the H chain. This crossover resulted in a variant H chain, which had 16 fewer amino acid residues than the normal CGP56901 H chain. These results show that peptide mapping is a useful "first-line" analytical tool in the characterization of the quality of the monoclonal antibody.

[Effects of endogenous nitric oxide on pulmonary artery hypertension and lung injury induced by endotoxin]

Changes in mean artery pressure (MAP), pulmonary artery pressure (PAP) and nitric oxide (NO) contents in inflow and outflow pulmonary blood(IPB,OPB) were observed after endotoxin lipopolysacchride (LPS) was injected i.v. in rabbits. Changes of PAP and lung injury were also observed after inhibitor of NO synthesis L-NNA or inhibitor of inducible NO synthesis AG was pre-injected by vein. The results showed that MAP decreased significantly after LPS administration, and 0.5-2h later PAP showed some increase (P<0.05) being maximum at PAP (1h) during which the content of NO in IPB was detectably decreased but NO in OPB did not. NO contents in OPB at 3h and in IPB and OPB at 5h increased significantly following LPS administration as compared with control.PAP correlated negatively with NO in IPB at the time before and 1h after LPS injection, which did not exist at 3 and 5h after LPS injection. After L-NNA pretreatment, when PAP elevated significantly, the MDA content in IPB and OPB also showed significant increase, while animal survival rate fell significantly. Light microscopic examination showed severe alveolar atelectasis, significant congestion and sequestration of leukocytes in lung tissue. When pretreated with AG, MAP elevated significantly in 3-5h, PAP remained unchanged. The MDA content in blood was lower at 5h in the LPS injected group with less pathological changes in lung tissue at 5h compared with the LPS group. The above results suggested that there was pulmonary hypertension in the early stage after endotoxin administration. The decrease of NO content in IPB may be one of the mechanisms underlying pulmonary artery hypertension(PAH).NO seemed to alleviate PAH and lung injury at the early stage after endotoxin administration. When iNOS was induced at the later stage, NO contributed to lung injury caused by endotoxin.

Conserved chromosomal location and genomic structure of human and mouse fatty-acid amide hydrolase genes and evaluation of clasper as a candidate neurological mutation

Fatty-acid amide hydrolase (FAAH) is a membrane-bound enzyme that degrades neuromodulatory fatty acid amides, such as oleamide and anandamide, and is expressed in the mammalian central nervous system. To evaluate FAAH genes as candidates for neurogenetic diseases in humans and mice, we have mapped the loci in both species and have determined their intron-exon structures. The human FAAH gene was mapped to region 1p34-p35, closely linked to D1S197 and D1S443, by using PCR analysis of somatic cell hybrid (SCH) and radiation hybrid mapping panels. Analysis of an SCH mapping panel and a mouse interspecific backcross panel has localized the Faah gene to the conserved syntenic region on mouse chromosome 4, close to the neurological mutation clasper. Faah gene rearrangements were excluded by Southern blot analysis of clasper DNA. No sequence abnormality was detected in PCR products containing the 15 exons and splice junctions of the mouse Faah gene. FAAH protein levels were normal in clasper mouse tissues as determined by enzyme activity assays and Western blotting.

Injection Molding of a Natural Rubber Compound: Simulation and Experimental Studies

Experimental and theoretical results are obtained for the cavity filling of a natural rubber (NR) compound. The shear rate and temperature dependent viscosity function based on the modified Cross model is fitted to experimentally measured viscosity data. A nonisothermal vulcanization model with nonisothermal induction time is fitted to the nonisothermal curing kinetic data obtained by differential scanning calorimetry (DSC). These data are utilized in the simulation of the cavity filling and curing stages. The pressure traces at various locations in the mold during cavity filling are obtained at different inlet and mold temperatures. The predicted results for the pressure traces are in good agreement with those measured in the cavity, but significantly lower than those measured in the nozzle. Evolution of the state of cure in the post-filling stage is predicted and compared with experimental data measured in moldings obtained at various cycle times. The measured states of cure in the moldings are in good agreement with their predicted values. Based on earlier flow studies of SBR compounds, it is shown that the discrepancy between the experimental and predicted pressure traces in the nozzle for the NR compound is due to high local pressure drops arising during the flow in juncture regions of the delivery system and the possibility of flow-induced crystallization. The importance of taking into account the entry pressure losses, viscoelastic effects and flow-induced crystallization in the injection molding process is strongly emphasized. The complexity of the issues related to this subject is discussed.

[The spectral broadening correction in peak blood flow velocity estimation]

Numerous effects contribute to the ultimate shape of output power spectrum in Doppler ultrasound blood flow measurement. The output Doppler spectrum is broadened by physiological sources related to blood flow velocity as well as some unexpected broaden components due to the nonideal acoustical factors of the ultrasound unit. Therefore, by using the classical Doppler equation, it will lead to overestimation of the maximum velocity in conventional Doppler blood flow measurement. In this paper, we present a modified Doppler equation which takes the intrinsic spectral broadening into account. The foundation of this method is introduced and the results of the in vivo experiment using this corrected equation are reported.

Evaluation of two X chromosomal candidate genes for Rett syndrome: glutamate dehydrogenase-2 (GLUD2) and rab GDP-dissociation inhibitor (GDI1)

The most likely cause of the Rett syndrome (RTT) is an X-linked dominant mutation lethal in hemizygous males. Previous exclusion mapping studies have identified putative regions for the RTT gene on the X chromosome. In the present study, we evaluated two candidate genes, glutamate dehydrogenase-2 (GLUD2) and rab GDP-dissociation inhibitor (GDI1/XAP-4), chosen because of their expression patterns and functions in the central nervous system and their location in the nonexcluded region of Xq. The intronless gene GLUD2, located in Xq25 and expressed in neuronal and testicular tissues, is involved in the metabolism of glutamate, a neurotransmitter reported to be elevated in the spinal fluid of RTT individuals. The GLUD2 gene was screened for mutations by Southern hybridization and by direct sequencing of polymerase chain reaction (PCR) products. The GDI1 gene in Xq28, also known as RABGDIA or XAP-4, encodes a human GDI that is expressed predominantly in neuronal and sensory tissues. All 11 exons and splice junctions of the GDI1 gene were PCR-amplified and sequenced directly or screened by single-strand conformation analysis. No mutation in either of these two genes was found in 22 RTT patients. Therefore, GLUD2 and GDI1 can be excluded as candidate genes for this syndrome.

Detection of ovarian cancer cells: comparison of a telomerase assay and cytologic examination

BACKGROUND

Telomerase is an enzyme essential for the normal replication of chromosomes. Telomerase activity is absent in most somatic cells in adults, but it is usually expressed in cancer cells, including ovarian carcinoma cells. Our principal goal was to compare the sensitivity of a telomerase assay, i.e., the telomeric repeat amplification protocol (TRAP) assay, with that of cytologic examination in detecting cancer cells in the peritoneal cavity of patients with ovarian carcinoma.

METHODS

TRAP assays and cytologic examinations were performed on peritoneal washings and ascitic fluids from 42 patients with active ovarian carcinoma. Control specimens included washings from 29 patients with benign ovarian diseases and ascitic fluids from 14 patients with liver failure. We also evaluated the stability of telomerase in ascitic fluids left unprocessed at room temperature as well as the ability of the TRAP assay to detect cancer cells in mixtures containing large numbers of normal cells.

RESULTS

Specimens from 37 (88%) of the 42 patients with ovarian carcinoma tested positive for telomerase. Cytologic examination detected cancer cells in only 27 of the telomerase-positive specimens (i.e., in specimens from 64% of the 42 patients). This difference of 24% (95% confidence interval = 17%-30%) in sensitivity between the two tests was statistically significant (two-sided P = .002). Specimens from five of the patients with ovarian carcinoma were cytologically negative and telomerase negative. All 43 control specimens were cytologically negative, but the TRAP assay detected telomerase in two of them. Telomerase activity was detected in unprocessed samples left at room temperature for 5 days and in mixtures containing a small number of cancer cells and a 2000- to 10000-fold excess of normal cells.

CONCLUSIONS

Assaying for telomerase is more sensitive than cytologic examination in detecting cancer cells in the peritoneal cavity of patients with ovarian carcinoma.

[Unambiguous turbulence measurement method and system using transverse Doppler techniques]

This paper introduces the principle of Doppler ambiguity process and the ambiguity reduction techniques using dual-sample volume. An unambiguous fluid turbulence measurement method using transverse Doppler and dual-sample volume cross-correlation techniques is described. An experimental turbulence detection system is designed. Theoretical and experimental results show that this method can eliminate the Doppler ambiguity spectra produced by transit-time effect, turbulence and velocity gradient in sample volume.

[Causes and influential factors of spectral broadening in Doppler flow signal]

Signals received are the resultant of the blood flow phasors in CW Doppler system and there are spectral broadening phenomena in it, in other words, frequency of signals corresponding to a moving RBC is not single. A model is presented that enables the detailed effects of spectral broadening to be calculated for a CW Doppler system by using geometric boundary argument. Results are given for the circular geometry.

Telomerase activity in benign and malignant epithelial ovarian tumors

BACKGROUND

Ovarian epithelial tumors include benign lesions lacking invasive and metastatic abilities (cystadenomas) in addition to malignant lesions (carcinomas). An intermediate category, called tumors of low malignant potential (LMP), is also recognized. The merit of this classification is being challenged because the clinical behavior of LMP tumors appears closer to that of cystadenomas than to that of carcinomas.

PURPOSE

To verify our hypothesis that the expression of the enzyme telomerase distinguishes these two categories of ovarian epithelial tumors, we examined and compared such expression in ovarian cystadenomas and carcinomas. By examining the expression of telomerase in LMP tumors, we then sought to determine if these tumors were more closely related to cystadenomas or to carcinomas with regard to telomerase expression.

METHODS

We examined a total of 64 consecutive ovarian tumors subdivided into 20 carcinomas, 17 LMP tumors, and 27 cystadenomas. We subsequently discarded three of the 27 cystadenomas because of the presence of admixed normal ovarian stroma in those specimens. Tumor subtyping was done without knowledge of the telomerase results, and telomerase assays were likewise interpreted without knowledge of tumor types. Telomerase activity was determined by use of the TRAP (i.e., telomeric repeat amplification protocol) assay. Differences between the proportions of tumors expressing this enzyme in each subgroup were evaluated by use of Fisher's exact test (two-sided).

RESULTS

Telomerase activity was detected in all 20 carcinomas and in all 17 LMP tumors examined. In contrast, it was not detected in 19 of the 24 cystadenomas. These differences between rates of telomerase expression in either carcinomas or LMP tumors and those in cystadenomas were statistically significant (P<.0001). All five of the telomerase-positive cystadenomas belonged to a variant called papillary cystadenomas, whereas none of the telomerase-negative cystadenomas belonged to this variant (P<.0001).

CONCLUSIONS AND IMPLICATIONS

The presence of telomerase expression in ovarian LMP tumors supports the merit of continuing to separate these tumors from cystadenomas, in spite of their apparent benign clinical course. The finding of telomerase expression in papillary cystadenomas suggests that such tumors may be mechanistically related to LMP tumors and should perhaps be reclassified as variants of LMP tumors. Lack of telomerase expression in ovarian cystadenomas raises questions about the alleged immortality of these tumors because expression of this enzyme is thought to be essential for continuous growth in adult tumors.

[Effects of a high-pass filter on the Doppler blood flow signal]

A high-pass filter is used to remove the large signals scattered or reflected from stationary and slow moving objects in many clinical CW Doppler units. theoretical results are presented that such a filter will lead to overestimate of the mean velocity of Doppler blood flow. As for different frequency signals, high-pass filter have different amplitudes and phase responses, consequently, nonlinear phase shift is produced. It is proved by computer experiment that nonlinear phase shift caused by high-pass filter hardly has any effects on Doppler flow power spectrum if the high-pass filter does not affect the amplitudes of signals.

[Cholecystokinin-octapeptide (CCK-8) reverses experimental endotoxin shock]

The effects of CCK-8 on the mean arterial pressure (MAP), blood components and path-morphological changes during endotoxin shock (endotoxin, 8 mg/kg b.w.iv.) in rats, as well as on the 24 h mortality rate (MR) of the lead-sensitized rats in endotoxin shock (endotoxin 1 microgram/100 g b.w.iv.) were observed. The results showed that injection of CCK in ES rats led to an increase in MAP, and a reduction of hematocrit and platelet as well as white cell count; the mortality rate decreased and the lesion in main organs lessened. It is suggested that release of endogenous CCK has important protective action during endotoxin shock.

Active constituents against HIV-1 protease from Garcinia mangostana

The ethanol extract of Garcinia mangostana L. (Guttiferae) showed potent inhibitory activity against HIV-1 protease. The activity-guided purification of the extract resulted in the isolation of two active, known compounds. The chemical structures of the isolated compounds were established by spectroscopic analyses as mangostin (IC50 = 5.12 +/- 0.41 microM) and gamma-mangostin (IC50 = 4.81 +/- 0.32 microM). The type of inhibition by both compounds is noncompetitive.

Anti-HIV triterpene acids from Geum japonicum

The methanol extract from the whole plant of Geum japonicum was found to inhibit the human immunodeficiency virus (HIV-1) protease. Through bioassay-directed fractionation of the extract, a new triterpene acid along with five known triterpene acids, ursolic acid, epipomolic acid, maslinic acid, euscaphic acid, and tormentic acid, were isolated. The structure of the new compound was determined by spectral means including 1H-1H COSY, HMQC, HMBC, and NOE experiments to be 2 alpha, 19 alpha-dihydroxy-3-oxo-12-ursen-28-oic acid (1). Of these compounds, 1, ursolic acid, and maslinic acid showed potent inhibitory activity against HIV-1 protease.

WAF1/CIP1 structural abnormalities do not contribute to cell cycle deregulation in ovarian cancer

Mutations in the WAF1/CIP1 gene were not found in 36 ovarian carcinomas, including tumours with loss of heterozygosity at the WAF1/CIP1 locus and/or lacking p53 mutations. In addition, no association was demonstrable between a polymorphism in a conserved region of the WAF1/CIP1 gene and ovarian carcinoma.

Autoprocessing: an essential step for the activation of HIV-1 protease

Human immunodeficiency virus type 1 (HIV-1) expresses its structural and functional proteins within Gag-Pol precursor polyproteins. Specific proteolytic processing of the precursors by the viral protease is critical for the maturation and infectivity of viral particles. To observe the influence of autoprocessing on the activation of recombinant HIV-1 protease, we constructed different HIV-1 protease forms, with or without the Phe-Pro bond directly upstream of the protease domain, and expressed them in Escherichia coli systems. We found that the presence of a short upstream sequence of the protease domain, which could generate the original N-terminus of the protease by autoproteolysis of the Phe-Pro bond, resulted in processing of active protease, whereas for a wild-type protease extended only with the initiator methionine, the proteolytic activity was not recovered. Our results suggested that autoprocessing of the direct upstream sequence of the protease domain is an essential step for the activation of recombinant HIV-1 protease in the E. coli expression system. Expression of HIV-1 protease as fusion proteins revealed that the existence of a fusion portion increased the accumulation of expressed protease by affecting its homotypic dimer formation.

Injection Molding of Rubber Compound with Rheology Affected by Vulcanization: Part II. Modeling and Experiment

Experimental and theoretical results are reported on the effect of vulcanization on viscosity and yield stress during cavity filling with an SBR compound. Rheological and vulcanization models were utilized in simulation of the cavity filling process. Numerical schemes was based on the hybrid approach of control volume finite-element and finite-difference techniques. The pressure profiles at various locations along the flow path in the mold during cavity filling were obtained by conducting the experiments at various mold and inlet temperatures and mold injection speeds. It was found that the predicted pressure profiles followed the trend determined in the experiments. Comparing two versions of the modified Cross viscosity models — with and without the effect of cure on viscosity — it appears that use of a viscosity model which accounts for the cure-effect improves the accuracy, and thus the usefulness, of the cavity pressure prediction models. Evolution of the state-of-cure in the postfilling process are predicted and compared with the state-of-cure in moldings. The predicted results on the development of the state-of-cure during the postfilling stage show good agreement with the experimental data. The rubber compound exhibits yield behavior during cavity filling at very low injection speeds. The modified Cross model was further extended to include the yield stress and was implemented in the simulation program. In the case of low injection speed, the results showed a significant improvement in the prediction of cavity pressure, compared with the earlier reported predictions.

Injection Molding of Rubber Compound with Rheology Affected by Vulcanization: Part I. Material Characterization

Rheological behavior of rubber is highly sensitive to the thermal history and cure kinetics. Rheological characterization for SBR compound is carried out using a capillary rheometer and modified Mooney viscometer. The viscosity function, which is not only temperature and shear-rate dependent but also cure-level dependent, is constructed. A modification of Cross model is proposed and verified to predict the rheological and chemorheological behaviors of SBR compounds. This rheological characterization is combined with vulcanization kinetic characterization. The parameters of vulcanization are obtained from DSC measurement under several nonisothermal conditions. The significance of correcting for temperature lag in the DSC measurements and the corresponding rate-of-vulcanization lag resulting from the nonisothermal DSC scan is illustrated. The proposed rheological function is further modified to incorporate the temperature- and state-of-cure-dependent yield behavior of rubber compounds at low shear rates. The proposed model is suitable for use in the simulation of processing operations.

Potential role of the inactivated X chromosome in ovarian epithelial tumor development

BACKGROUND

Ovarian epithelial tumors can be divided into subcategories often regarded as different stages of neoplastic transformation. Cystadenomas belong to the least aggressive subgroup and are noninvasive and nonmetastatic. Ovarian tumors of low malignant potential (LMP) are intermediate between cystadenomas and carcinomas and show markedly reduced invasive and metastatic abilities. Invasion and metastasis are the hallmarks of carcinomas, which constitute the most aggressive subgroup and can be further subdivided into different grades.

PURPOSE

We performed comparative allelotype analyses of ovarian cystadenomas, LMP tumors, and carcinomas, reasoning that such analyses could provide clues about the molecular determinants of their phenotypic differences. Because we realized that allelic losses involving the X chromosome might be associated with LMP tumor development, we determined whether such losses were interstitial and whether they involved the active or the inactive X chromosome.

METHODS

Frequencies of loss of heterozygosity (LOH) at specific loci in every chromosomal arm were determined in 16 ovarian cystadenomas, 23 ovarian LMP tumors, 15 low-grade ovarian carcinomas, and 35 high-grade ovarian carcinomas by use of either the polymerase chain reaction (PCR) or Southern blot analyses. We took advantage of the fact that DNA methylation is an important mechanism of X-chromosome inactivation to determine whether losses involving the X chromosome were in the active or the inactive copy. We analyzed the methylation status of retained alleles on the X chromosome by determining whether they could be amplified by PCR after digestion with the methylation-sensitive restriction endonuclease Hpa II.

RESULTS

High-grade carcinomas contained frequent(>50%) LOH in four autosomal chromosome arms, i.e., 6q, 13q, 17p, and 17q. Except for 13q, these same chromosomal arms showed frequent LOH in low-grade carcinomas. LOH in autosomal chromosomes was comparatively rare in LMP tumors and was absent in cystadenomas. In contrast, half (eight of 16) of LMP tumors informative for a locus in the proximal portion of chromosome Xq showed LOH at that locus. These losses were the result of interstitial deletions in six of the eight cases and involved the inactive copy of the X chromosome exclusively. Similar losses in the X chromosome were not seen in either cystadenomas or low-grade carcinomas.

CONCLUSIONS AND IMPLICATIONS

LOH at multiple loci is associated with the development of ovarian carcinomas but not with the development of cystadenomas and LMP tumors. However, the integrity of a locus in chromosome Xq that possibly escapes X-chromosome inactivation is important for the control of LMP tumor development. The fact that this locus does not appear to be involved in the genesis of low-grade carcinomas suggests that LMP tumors are not precursors of such carcinomas.

[Tissue culture and rapid propagation of Pinellia ternata (Thunb) Breit]

In this papar, selection of the explaints and morphogenesis of the plantlet involved in the tissue culture of Pinellia ternata have been investigated, the effect of different combinations of growth-regulating substances on the morphogenesis has been studied, and the result of the establishment of clonal rapid propagation system and the transplanting of test-tube Pinellia seedlings has also been reported.

Molecular alterations of the AKT2 oncogene in ovarian and breast carcinomas

The AKT2 gene is one of the human homologues of v-akt, the transduced oncogene of the AKT8 virus, which induces lymphomas in mice. In previous studies, AKT2, which codes for a serine-threonine protein kinase, was shown to be amplified and overexpressed in some human ovarian carcinoma cell lines and amplified in primary tumors of the ovary. To confirm and extend these findings, we conducted a large-scale, multicenter study of AKT2 alterations in ovarian and breast cancer. Southern-blot analysis demonstrated AKT2 amplification in 16 of 132 (12.1%) ovarian carcinomas and in 3 of 106 (2.8%) breast carcinomas. No AKT2 alteration was detected in 24 benign or borderline tumors. Northern-blot analysis revealed overexpression of AKT2 in 3 of 25 fresh ovarian carcinomas which were negative for AKT2 amplification. The difference in the incidence of AKT2 alterations in ovarian and breast cancer suggests a specific role for this gene in ovarian oncogenesis. No significant association was found between AKT2 amplification and amplification of the proto-oncogenes MYC and ERBB2, suggesting that amplification of AKT2 defines an independent subset of breast and ovarian cancers. Ovarian cancer patients with AKT2 alterations appear to have a poor prognosis. Amplification of AKT2 was especially frequent in undifferentiated tumors (4 of 8, p = 0.019), suggesting that AKT2 alterations may be associated with tumor aggressiveness.

Genetic disparity between morphologically benign cysts contiguous to ovarian carcinomas and solitary cystadenomas

BACKGROUND

Ovarian carcinomas occasionally contain large, histologically benign cysts contiguous to the clearly malignant areas (cystadenocarcinomas). The question of whether such cysts are remnants of pre-existing benign tumors (cystadenomas) or constitute integral components of the carcinomas is important in clarifying the role of cystadenomas in ovarian carcinogenesis. It is also important for our general understanding of tumor heterogeneity, a phenomenon thought to result from the gradual accumulation of genetic abnormalities in initially homogeneous tumors. This question is also pertinent to the clinical management of ovarian cystadenomas, which are frequent in women of childbearing age and are usually treated surgically based on the possibility that they may give rise to carcinomas.

PURPOSE

Reasoning that molecular markers of ovarian malignancy would be confined to the histologically malignant portions of cystadenocarcinomas if the morphologically benign portions are in fact pre-existing typical cystadenomas, we sought to verify that mutations in the p53 tumor suppressor gene are markers of malignancy in ovarian tumors and to determine the distribution of such mutations in cystadenocarcinomas.

METHODS

We used immunohistochemical and DNA-sequencing techniques to analyze 46 ovarian carcinomas, 21 ovarian tumors of low malignant potential, and 16 solitary cystadenomas for the presence of p53 mutations. We then used similar techniques to examine the distribution of such mutations in different portions of cystadenocarcinomas. The observed differences in mutation frequencies were analyzed by the two-tailed Fisher's exact test.

RESULTS

Mutations in the p53 gene were present in 24 (52%) of the 46 carcinomas, but they were absent in the 21 tumors of low malignant potential (P < .0001) and the 16 solitary cystadenomas (P = .0002). Six of six cystadenocarcinomas with p53 mutations showed the presence of the same mutations in the adjacent, histologically benign cysts. The mutations were seen not only in cells immediately adjacent to the carcinomas, but also throughout the morphologically benign cysts. Twenty (83%) of the 24 cases showing mutation of one p53 allele also showed loss of genetic heterozygosity, suggesting that the other p53 allele was deleted. Such allelic loss, if present in morphologically malignant portions of cystadenocarcinomas, was also observed in the contiguous cysts.

CONCLUSIONS

Ovarian carcinomas can be distinguished from ovarian cystadenomas and tumors of low malignant potential by p53 mutations. The fact that the mutations were present in histologically benign cysts contiguous to ovarian carcinomas suggests that such cysts are not typical cystadenomas and may carry a genetic predisposition to carcinogenesis that is not present in ordinary cystadenomas.

Regulation of metallothionein gene expression in Cd- or Zn-adapted RK-13 cells

We explored the molecular genetics underlying the massive induction of isoMTs by Zn2+ or Cd2+ in metal tolerant rabbit kidney (RK-13) sub-line cells, using band shift assays and Southern blotting analysis. In sub-line cells accommodated to intermediate metal concentrations (100 microM Zn2+; 1-20 microM Cd2+) evidence suggested that the increase in the capacity for isoMT synthesis is brought about by an increased binding activity of the nuclear transcription factors MTF-1 and Sp1. Using quantitative band shift analysis with a mouse MRE-d oligonucleotide probe, the binding of both transcription factors was found to be enhanced two to three times over the binding activity measured in the unexposed parental RK-13 cells. Their increase in binding activity is probably the cause of the overexpression of MT genes and the development of metal tolerance in these cells. In cells tolerant to the highest concentrations of metal the analysis of Southern blot signals revealed MT gene amplification to be the most probable cause of the increased MT production. Thus, in cells of sub-lines growing in the presence of 350 microM Zn2+, two of the isoMT genes were coordinately triplicated and in cells tolerant to 150 microM Cd2+ one isoMT gene was amplified two-fold.

[Protective effect of endothelium-derived relaxing factor on ischemic (hypoxic) and reperfused (reoxygenated) myocardium]

The present study is undertaken to investigate the effects of NO, its inhibitor L-NNA and its procursor L-Arg on the status of myocardial tissue during ischemia (hypoxia) and reperfusion (reoxygenation) in two different models, i.e. Langendorff heart and cultured heart cells of rat. The results were as follows: (1) When heart perfusion was stopped for 30 min and reinstitued for 20 min with K-H buffer containing NO, the coronary flow rate (CFR), left ventricular pressure (LVP) and +/- dp/dtmax increased significantly. When NO was replaced by L-NNA opposite effects were observed. L-Arg alone was without effect on CFR, LVP and +/- dp/dtmax, but attenuated the decreasing effect of L-NNA on CFR. NO decreased MDA and NAGase content of myocardium while L-NNA increased them. (2) When cultured ventricular myocytes were subjected to hypoxia for 30 min and reoxygenated for 20 min, none of the substances under investigation showed any effects on Ca2+ content of heart cells, but all of them decreased MDA, NAGase content of the culture tissue after reoxygenation. The above findings show that NO plays an important role in protecting myocardium from ischemic and reperfused injury by improving blood supply of reperfused myocardium and attenuation of oxygen free radical injury.

Comparison of HIV-1 protease expression in different fusion forms

Earlier observations showed that the expression of recombinant protease of human immunodeficiency virus type-1 (HIV-1 PR) was usually in a low level, and its proteolytic activity and hydrophobicity were believed to be toxic for the host cells. Various constructs were investigated that contained an N-terminal extended HIV-1 PR gene (PR107) in order to find a system which can express this protease in high level. The constructs of PR107 gene expressed as fusion proteins either with glutathione S-transferase (GST) by pGEX-PR107 or with maltose-binding protein (MBP) by pMAL-PR107 showed that the full length of fusion protein exhibited self-cleavage in E. coli. The results from expression experiments indicated that the size of the fusion portion does not affect the self-processing of fused HIV-1 PR to release its mature form, despite the attachment of only one subunit of the dimeric protease to GST or MBP. The construct, pET-PR107, under the control of strong bacteriophage T7 promoter system, did not show clear advantages for expression of this HIV-1 PR. Comparing these three constructs, the pGEX-PR107 system showed the highest expression level. Quantitative immuno-blotting indicated that the amount of HIV-1 PR expressed by pGEX-PR107 was twice that expressed by pMAL-PR107, and thrice that expressed by pET-PR107. More than 1 mg of pure HIV-1 PR from per liter culture of E. coli. DH5 alpha containing pGEX-PR107 can be obtained via the purification procedures [Biochem. Mol. Biol. International, (1995) 35:899-912].(ABSTRACT TRUNCATED AT 250 WORDS)

Expression and purification of active form of HIV-1 protease from E.coli

We have subcloned an N-terminal extended protease gene of human immunodeficiency virus (HIV) type 1 that is encoded in the protease domain of the pol open reading frame into expression vector pGEX-KG. A relatively high level of expression of recombinant HIV-1 protease (PR) was achieved with isopropyl beta-D-thiogalactoside (IPTG) induction and glucose supplement. An isolation method consisting of denaturation of protein and followed by refolding was developed for releasing this recombinant HIV-1 PR into the soluble phase since most of the expressed protease was initially present in insoluble inclusion bodies. High purity of this recombinant HIV-1 PR was obtained by sequential purification using Sephadex G-50 gel filtration and CM-23 cellulose cation exchange chromatography, yielding the protease more than 1 mg per liter culture. N-terminal amino acid sequence analysis showed that the recombinant HIV-1 PR underwent autocleavage from the fusion protein during expression. SDS-PAGE indicated that the molecular weight of this recombinant HIV-1 PR is 11 kDa. This recombinant HIV-1 PR showed proteolytic activity for the synthetic peptide substrates corresponding to the sequence at the Gag MA/CA and Pol p6*/PR junctions. The purified enzyme whose specific activity for the heptapeptide SQNYPIV was 848.7 nmol*min-1*mg protease-1 also processed recombinant polyprotein Gag41 as its substrate.

Primary structures of seven metallothioneins from rabbit tissue

Metallothionein from tissues of rabbits exposed to cadmium chloride was separated into seven distinct isoforms by reverse-phase liquid chromatography and their complete amino acid sequences were determined. Five of the seven isometallothioneins showed structural features so far not identified in other mammalian metallothioneins. Thus, two isoproteins contain a polypeptide with a chain length of 62 rather than 61 amino acid residues. Two isoforms are characterized by an additional positive charge and one by the presence of an isopeptide bond between aspartic acid and serine in the N-terminal half of the protein. The isoproteins characterized were identified from different sources: rabbit liver and kidney and a rabbit kidney cell-line (RK-13). In all three, the structural characteristics of the individual isoforms are retained, indicating that in the different tissues the same mechanisms control the synthesis and the stability of the different cadmium-induced isoMTs.

Isolation of a novel fluorescent toxin from the coral reef crab, Lophozozymus pictor

A novel toxin has been isolated from an aqueous extract of the coral reef crab Lophozozymus pictor by a combination of ion exchange and two-dimensional thin layer chromatography. The isolated toxin exhibited bioactivities similar to palytoxin (toxicity response of mice, cytotoxicity towards HeLa cells and release of potassium ions from rat erythrocytes). Unlike palytoxin it gave an intense blue fluorescence under ultraviolet light. A fluorescence scan showed that the toxin had a maximum excitation wavelength at 285 nm and a maximum emission wavelength at 355 nm. The toxin was distinguishable from palytoxin when analysed by high performance capillary electrophoresis and reverse phase high performance liquid chromatography.

Histologically benign or low-grade malignant tumors adjacent to high-grade ovarian carcinomas contain molecular characteristics of high-grade carcinomas

It is presently not clear if ovarian carcinomas arise de novo or from benign precursors (cystadenomas) and if high-grade malignant tumors (carcinomas) develop from preexisting low-grade carcinomas. The presence of allelic losses on chromosome 11p15.5 distinguishes high-grade ovarian carcinomas from either low-grade carcinomas or cystadenomas. We therefore examined the distribution of such losses in different parts of heterogeneous tumors showing mixed histological grades or showing adjacent large histologically benign neoplasms. The results showed that all neoplastic areas, including those that were histologically benign or compatible with low-grade carcinomas, contained allelic losses at the above locus. This suggests that the morphologically less aggressive portions of these heterogeneous tumors were not typical cystadenomas or low-grade carcinomas and contained molecular abnormalities indicative of at least a predisposition to the high-grade carcinoma phenotype.

Induction of metallothionein synthesis by cadmium and zinc in cultured rabbit kidney cells (RK-13)

The effects of increasing concentrations of Zn(II) and Cd(II) on the expression of the four isometallothioneins (isoMTs), namely MT-1a, MT-2a, MT-2d and MT-2e, in rabbit kidney cells (RK-13) and the development of cellular tolerance to these metal ions were studied. The results showed that, whereas in parental cells MT concentration was low and composed nearly exclusively of MT-2a and MT-1a, all four isoMTs increased massively in abundance when the cells were exposed to toxic concentrations of Zn(II) or Cd(II), the relative increase being largest in the two minor isoforms MT-2d and MT-2e. While the response of the four isoMTs to the challenge by Zn(II) or Cd(II) was qualitatively comparable, there were differences in sensitivity and delay time, Cd(II) being the more efficient inducer and much faster in eliciting the onset of isoMT synthesis. An even larger production of isoMTs resulted when RK-13 cells were cultured in the presence of a series of metal concentrations yielding sub-lines of increased metal tolerance. In this instance too, there were marked differences in the response to Cd(II) and Zn(II). Thus, in cells of sub-lines selected for tolerance to moderate concentrations of Cd(II) the kinetic analysis of isoMT accretion gave indications of a saturable induction process while no such evidence was forthcoming for Zn(II). In sub-line cells selected for tolerance to the highest concentrations of Cd(II) or Zn(II) isoMT formation was increased by another order of magnitude, reaching for some isoforms a 100- to 1000-fold augmentation over the amounts measured in cells of the unexposed parental cells. A potentiation of this magnitude goes beyond the range of ordinary regulation of gene expression. It is to be viewed instead as an enlargement of the capacity of isoMT synthesis acquired by a variety of mechanisms in the surviving cells.

Resolution and quantification of four metallothionein isoforms from rabbit kidney cells

Reversed-phase high-performance liquid chromatography coupled with an on-line integrating chromatographic data system was used to separate and quantify the four major isometallothioneins MT-1a, MT-2a, MT-2d, and MT-2e present in metallothionein samples from cultured rabbit kidney cells as prepared by gel-filtration and/or ion-exchange chromatography. The standard curves for each of these isoforms showed closely comparable linear correlations between the amount of protein applied to the column and their integrated absorbance peak area at 220 nm. The lower limit of quantification is 30 pmol, sufficient to assess basal isometallothionein concentrations and to follow their variation upon metal exposure.