Diversity of core promoter mutations in immune clearance phase of chronic HBV infection

BACKGROUND/AIMS

Transcription of HBV (hepatitis B virus) pre-core and pre-genomic mRNAs is controlled by core promoter. Therefore, mutations in the core promoter region might change the activity of liver diseases through an altered transcriptional level of the mRNA. The present study was carried out to determine the diversity of HBV core promoter sequences in chronic HBV carriers.

METHODS

DNA sequences in the core promoter region were determined after cloning the PCR product. Two groups of chronic HBV carriers with HBeAg, including five cases of asymptomatic carriers (ASCs, 21 clones) and eight with chronic hepatitis (CH, 50 clones) were studied.

RESULTS

Mutations in the core promoter were found in three out of the ASCs (11 clones), and in all eight cases in the CH group (48 clones). While mutations at nucleotide 1762 (A-->T) and 1764(G-->A) were not found in ASC, mutations at the same positions were found in all the cases of CH group (40 clones) (P=0.003). Diverse patterns of mutations in the core promoter were observed in each patient in the CH group.

CONCLUSIONS

Further studies are needed to determine whether the diversity of HBV core promoter mutations has clinical significance such as the seroconversion of HBeAg to anti-HBe.

Isolation and characterization of a mutant defective in the production of methanol dehydrogenase from a new restricted facultative methanol-oxidizing bacterium

A new restricted facultative methanol-oxidizing bacterium Methylobacillus sp. strain SK1 (DSM 8269) was subjected to insertion mutagenesis studies with the transposon Tn5 to generate mutants deficient in the production of methanol dehydrogenase (MDH). The transposon was conjugally transferred into the methylotroph by using the triparental mating procedure. The mutants induced by Tn5 were selected directly from a plate containing succinate by using the allyl alcohol selection procedure. The transposition of Tn5 to the bacterium showed a moderate transposition frequency (10(-5) - 10(-6)). Southern hybridization analysis confirmed that the transposon Tn5 was inserted into the chromosomal DNA of the mutants. In addition, the mutants had no RNA transcripts produced from the mdh gene, as judged by Northern blot analysis. The mutants could neither grow on methanol nor produce MDH protein, as determined by Western blot analysis with anti-MDH antibody. These results suggest that Tn5 mutagenesis maybe a useful tool for the molecular analysis of a facultative methanol-oxidizing bacterium.

Chromosome abnormalities in a referred population for suspected chromosomal aberrations: a report of 4117 cases

A cytogenetic study was performed on 4,117 Korean patients referred for suspected chromosomal abnormalities. Chromosome aberrations were identified in 17.5% of the referred cases. The most common autosomal abnormality was Down syndrome and Turner syndrome in abnormalities of sex chromosome. The proportions of different karyotypes in Down syndrome (trisomy 21 92.5%, translocation 5.1%, mosaic 2.4%) were similar to those reported in other countries. However, it was different in Turner syndrome (45, X 28.1%, mosaic 50.8%, 46, X, del (Xq) 4.4%, 46, X, i (Xq) 16.7%), in which proportions of mosaics and isochromosome, 46, X, i(Xq), were higher than those reported in other countries. In structural chromosome aberrations of autosome, translocation was the most common (43.6%), and duplication (21.3%), deletion (14.4%), marker chromosome (7.9%) and ring chromosome (4.0%) followed in order of frequency. Rates of several normal variant karyotypes were also described. Inversion of chromosome 9 was observed in 1.7% of total referred cases.

Murine leukemia provirus-mediated activation of the Notch1 gene leads to induction of HES-1 in a mouse T lymphoma cell line, DL-3

Constitutive activation of Notch signaling is known to be associated with tumorigenesis. In a mouse T lymphoma cell line, DL-3, we found that a murine leukemia provirus was inserted in the Notch1 locus, which led to marked expression of a virus-Notch1 fusion mRNA encoding an intracellular portion of the Notch1 protein. Furthermore, expression and nuclear localization of this constitutively active form of Notch1 protein were confirmed. Corresponding to this finding, the transcription of the hairy/enhancer of split (HES-1) gene, a known target of Notch1 signaling, was elevated in this cell line. A potential role for overexpressed HES-1 in the development of the lymphoma was discussed.

Characterization of mouse dishevelled (Dvl) proteins in Wnt/Wingless signaling pathway

The dishevelled (dsh) gene family encodes cytoplasmic proteins that have been implicated in Wnt/Wingless (Wg) signaling. To demonstrate functional conservation of Dsh family proteins, two mouse homologs of Drosophila Dsh, Dvl-1 and Dvl-2, were biochemically characterized in mouse and Drosophila cell culture systems. We found that treatment with a soluble Wnt-3A leads to hyperphosphorylation of Dvl proteins and a concomitant elevation of the cytoplasmic beta-catenin levels in mouse NIH3T3, L, and C57MG cells. This coincides well with our finding in a Drosophila wing disc cell line, clone-8, that Wg treatment induced hyperphosphorylation of Dsh (Yanagawa, S., van Leeuwen, F., Wodarz, A., Klingensmith, J., and Nusse, R. (1995) Genes Dev. 9, 1087-1097). Furthermore, we showed that mouse Dvl proteins affect downstream components of Drosophila Wg signaling as Dsh does; overexpression of Dvl proteins in clone-8 cells results in elevation of Armadillo (Drosophila homolog of beta-catenin) and Drosophila E-cadherin levels, hyperphosphorylation of Dvl proteins themselves, and inhibition of Zeste-White3 kinase-mediated phosphorylation of a microtubule-binding protein, Tau. In addition, casein kinase II was shown to coimmunoprecipitate with Dvl proteins, and Dvl proteins were phosphorylated in these immune complexes. These results are direct evidence that Dsh family proteins mediate a set of conserved biochemical processes in the Wnt/Wg signaling pathway.

Two-phase methanization of food wastes in pilot scale

A 5 ton/d pilot scale two-phase anaerobic digester was constructed and tested to treat Korean food wastes in Anyang city near Seoul. The easily degradable presorted food waste was efficiently treated in the two-phase anaerobic digestion process. The waste contained in plastic bags was shredded and then screened for the removal of inert materials such as fabrics and plastics, and subsequently put into the two-stage reactors. Heavy and light inerts such as bones, shells, spoons, and plastic pieces were again removed by gravity differences. The residual organic component was effectively hydrolyzed and acidified in the first reactor with 5 d space time at pH of about 6.5. The second, methanization reactor converted the acids into methane with pH between 7.4 and 7.8. The space time for the second reactor was 15 d. The effluent from the second reactor was recycled to the first reactor to provide alkalinities. The process showed stable steady-state operation with the maximum organic loading rate of 7.9 kg volatile solid (VS)/m3/d and the volatile solid reduction efficiency of about 70%. The total of 3.6 tons presorted MSW containing 2.9 tons of food organic was treated to produce about 230 m3 of biogas with 70% (v/v) of methane and 80 kg of humus. This process is extended to full-scale treating 15 tons of food waste a day in Euiwang city and the produced biogas is utilized for the heating/cooling of adjacent buildings.

Degraded diet induced thermogenesis induced by 20 days of 6 degrees head down bed rest and effect of resistance training

In the 21st century, our dream of living in a space will finally become reality. To understand the effects of microgravity on energy expenditure and possible countermeasure against them is important to maintain human health in space. Diet Induced Thermogenesis (DIT) is an increase in energy expenditure after ingestion of a meal, and accounts for 10% of total daily energy expenditure. Recently, the important role of DIT in regulating obesity is suggested. Basal Energy Expenditure (BEE), on the other hand, is the minimum energy expenditure required to keep on living, and accounts for 60-75% of total energy expenditure. Despite the importance of DIT, no information about DIT in microgravity and possible effects of exercise training is available. Therefore, we aimed to investigate, first, the effects of 20-days of 6 degrees head down tilting bed rest (HDBR) on postabsorptive energy expenditure (PEE), DIT, and BEE. Second, the effects of resistance training during HDBR on DIT and BEE.

Synthesis, cloning and expression of the single-chain Fv gene of the HPr-specific monoclonal antibody, Jel42. Determination of binding constants with wild-type and mutant HPrs

The monoclonal antibody Jel42 is specific for the Escherichia coli histidine-containing protein, HPr, which is an 85 amino acid phosphocarrier protein of the phosphoenolpyruvate:sugar phosphotransferase system. The binding domain (Fv) has been produced as a single chain Fv (scFv). The scFv gene was synthesized in vitro and coded for pelB leader peptide-heavy chain-linker-light chain-(His)(5) tail. The linker is three repeats from the C-terminal repetitive sequence of eukaryotic RNA polymerase II. This linker acts as a tag; it is the antigen for the monoclonal antibody Jel352. The codon usage was maximized for E.coli expression, and many unique restriction endonuclease sites were incorporated. The scFv gene incorporated into pT7-7 was highly expressed, yielding 10-30% of the cell protein as the scFv, which was found in inclusion bodies with the leader peptide cleaved. Jel42 scFv was purified by denaturation/renaturation yielding preparations with K(d) values from 20 to 175 nM. However, based upon an assessment of the amount of active refolded scFv, the binding dissociation constant was estimated to be 2.7 +/- 2.0 nM compared with 2.8 +/- 1.6 and 3.7 +/- 0.3 nM previously determined for the Jel42 antibody and Fab fragment respectively. The effect of mutation of the antigen HPr on the binding constant of the scFv was very similar to the properties determined for the antibody and the Fab fragment. It was concluded that the small percentage ( approximately 6%) of refolded scFv is a true mimic of the Jel42 binding domain and that the incorrectly folded scFv cannot be detected in the binding assay.

Pulmonary Opacities in a Patient with Essential Thrombocytopenia

This regular feature will enhance your knowledge of imaging technology in oncologic diagnosis, treatment, and evaluation.

The comparative molecular study between Bombycidae and Saturniidae based on mtDNA RFLP and cytochrome oxidase I gene sequences: implication for molecular evolution

The phylogenetic relationships between Bombyx mori and Bombyx mandarina species of Bombycidae, and Antheraea yamamai and Antheraea pernyi species of Saturniidae were investigated based on mtDNA RFLP and cytochrome oxidase I gene. The sizes of the mtDNA of all the species were estimated at approximately 16 kbp +/- 500 bp by total length of all the restricted fragments and no variation in size was recognized. Of the fourteen different restriction endonucleases used, BamHI, HindIII, PstI, EcoRI and XbaI showed RFLP. Among these, only HindIII showed RFLP between B. mori and B. mandarina. A comparative analysis of sequences was also conducted with the mitochondrial cytochrome oxidase I genes of each species. The results indicated that B. mori shared a 97%, 85% and 87% sequence identity with B. mandarina, A. yamamai and A. pernyi, respectively. B. mandarina shared a 87% and 88% sequence identity with A. yamamai and A. pernyi, respectively. A. yamamai shared 92% sequence identity with A. pernyi. The results of the phylogenetic analysis exhibited monophyly and confidence limits of more than 99% in all trees for both Bombycidae and Saturniidae.

Localized amyloidosis of the respiratory system: CT features

PURPOSE

Amyloidosis includes a spectrum of diseases associated with an abnormal extracellular deposition of amyloid. The respiratory system is involved in approximately 50% of patients with amyloidosis. The purpose of this review is to present the CT findings of localized amyloidosis of the respiratory system.

METHODS

We reviewed the CT findings of localized amyloidosis of the respiratory system from the previous reports and our experiences.

RESULTS

Three patterns of involvement in respiratory system are presented: tracheobronchial nodular and diffuse parenchymal. CT demonstrates nodules, plaques, or diffuse thickening of the airways with calcification. Postobstructive collapse is associated in case of diffuse airway involvement. Parenchymal nodules have sharp and lobulated margins with peripheral or subpleural locations. High-resolution CT shows reticular opacities, interlobular septal thickening, and small, well-defined nodules of 2 to 4-mm in diameter predominantly in the subpleural regions.

CONCLUSION

Amyloidosis of respiratory system has variable findings and CT scans clearly depict extent and distribution of the disease, its postobstructive pulmonary complication, and other associated findings such as calcification and lymphadenopathy.

Modulation of monocyte chemokine production and nuclear factor kappa B activity by oxidants

Reactive oxygen species can directly damage tissue. In this setting, amplification of tissue damage also occurs through infiltration of inflammatory cells either acutely or chronically. Several recent studies suggest that reactive oxygen species stimulate production of certain chemokines, which are potent chemoattractants for inflammatory cells. In the present study, we examined whether oxidants, generated by the combination of xanthine and xanthine oxidase (X/XO), alter chemokine production by monocytes and U937 cells. Our findings demonstrate that X/XO stimulates monocytes, but not U937 cells, to produce increased amounts of interleukin-8 (IL-8) and monocyte chemoattractant protein. This effect is attenuated by pretreatment with dimethylsulfoxide (DMSO), a scavenger of hydroxyl radicals, but is not affected by superoxide dismutase or catalase. In contrast, X/XO-induced cytotoxicity, evidenced by lactate dehydrogenase release, is mediated primarily by hydrogen peroxide, as catalase reverses this effect. Finally, exposure to X/XO causes an increase in nuclear factor kappa B (NF-kappaB), and this effect is attenuated by DMSO. These studies suggest that reactive oxygen species can induce production of molecules that amplify inflammation through attraction of inflammatory cells. It appears the hydroxyl radical is the principal oxidant species involved in stimulation of chemokine production.

Integration of cytogenetic with recombinational and physical maps of mouse chromosome 16

To link the cytogenetic map for mouse chromosome 16 (Chr 16) to the more detailed recombinational and physical maps, multiple probes were mapped by fluorescence in situ hybridization (FISH). Sixteen large insert clones (YACs, BACs, and PACs) containing markers that have been assigned to the Chr 16 recombinational map were localized to a cytogenetic band or subband by high-resolution FISH. This linkage of the cytogenetic and recombinational maps provides a useful tool for assigning new probe locations and for defining breakpoints in mice with chromosomal rearrangements. A direct application of these probes is demonstrated by identifying mice trisomic for distal Chr 16 using FISH analysis of interphase nuclei.

Intellectual outcomes of patients with congenital hypothyroidism not detected by neonatal screening

Mental retardation is a major sequela of delayed treatment of congenital hypothyroidism. In this study, we investigated the intellectual outcomes of patients with congenital hypothyroidism diagnosed before a nationwide screening project started. Eighty-two patients had intelligence tests done while in the euthyroid state. Their mean intelligence quotient (IQ) was 78 +/- 21 (+/- SD) (n = 79). The mean verbal IQ was significantly higher than the mean full-scale IQ. The mean IQs of both ectopic thyroid (84 +/- 21, n = 28) and dyshormonogenic patients (85 +/- 14, n = 18) were significantly higher than that of patients with athyrosis (64 +/- 18, n = 19) (p < 0.05). Patients who were treated before 3 months of age had significantly higher mean IQs (90 +/- 16, n = 16) than those treated after 3 months (75 +/- 21, n = 63) (p < 0.01). Our results confirm that both patients with ectopic thyroids and those with dyshormonogenesis have better intellectual outcomes than athyrotic patients do, and that early treatment improves the intellectual outcome of patients with congenital hypothyroidism.

Cardiovascular reserve to orthostatic stress in active-living elders

A preliminary field survey of cardiovascular responses during orthostatic stress in active-living very old elders over 70 years old in Japan was conducted. The subjects were 36 active-living elders (age; mean=77.8 yrs, 70-88 yrs) in rural Japan (mountain area), and 9 healthy young persons (mean 22 yrs). During short-term (2min) orthostatic stress, active-living elders (>70 years old) had age-dependent orthostatic tachycardia and hypertension (by increased pulse pressure), and significantly decreased heart rate fluctuations with maintained blood pressure fluctuations. We conclude that cardiovascular changes with aging itself do not necessarily cause orthostatic intolerance.

Development of videostrobokymography for the quantitative analysis of laryngeal vibratory pattern

We developed a new analysis technique for the assessment of irregular vibratory movement of vocal folds. Successive frames of pre-recorded video images from videostroboscopy were transferred to computer memory and vibratory track of one selected point was described as a waveform by displaying the same lines of all frames along the vertical direction. Glottal area waveform, which was normalized with glottal length, was composed to quantitatively assess the overall vibratory pattern of vocal folds. By applying this technique, irregular vibratory patterns of multiple regions, such as asynchronized registration of glottal cycles, could be easily visualized. It would be possible to monitor and analyze the pathologic changes of vocal fold movement by means of this newly developed system.

TNF-alpha-mediated apoptosis is initiated in caveolae-like domains

Caveolae-like domains (CLDs) have been hypothesized to mediate apoptosis, since they contain sphingomyelin and initiate the conversion of sphingomyelin to ceramide. To address whether CLDs are directly involved in apoptosis, CLDs from U937 cells were isolated, taking advantage of their detergent insolubility and low density. The CLDs contained alkaline phosphatase as well as many signaling molecules, including Fyn, protein kinase Calpha, Raf-1, phospholipase Cgamma1, and tyrosine phosphoproteins. Immunoblotting and immunofluorescent data showed that TNF receptor 1 colocalized with CD36 in CLDs, suggesting that TNF-alpha-initiated apoptosis occurs in CLDs. When cells were incubated with lipoprotein-deficient medium, the cholesterol concentration was greatly decreased in CLDs but not in other fractions, implying that the CLDs were selectively disrupted. In the CLD-disrupted cells, the surface expression of TNF receptor 1 and CD36 was significantly reduced. Analysis of cellular morphology, percent DNA fragmentation, DNA laddering, and caspase-3 activity showed that TNF-alpha-mediated apoptosis was blocked in CLD-disrupted cells, whereas anti-Fas-mediated apoptosis was not. Since Fas was not found in CLDs of Jurkat cells, apoptosis by Fas ligation might not require CLDs. Taken together, these data strongly imply that TNF-alpha-mediated apoptosis is initiated in CLDs.

Precursor of pro-apoptotic cytokine modulates aminoacylation activity of tRNA synthetase

Endothelial monocyte activating polypeptide II (EMAPII) is a cytokine that is specifically induced by apoptosis. Its precursor (pro-EMAPII) has been suggested to be identical to p43, which is associated with the multi-tRNA synthetase complex. Herein, we have demonstrated that the N-terminal domain of pro-EMAPII interacts with the N-terminal extension of human cytoplasmic arginyl-tRNA synthetase (RRS) using genetic and immunoprecipitation analyses. Aminoacylation activity of RRS was enhanced about 2.5-fold by the interaction with pro-EMAPII but not with its N- or C-terminal domains alone. The N-terminal extension of RRS was not required for enzyme activity but did mediate activity stimulation by pro-EMAPII. Pro-EMAPII reduced the apparent Km of RRS to tRNA, whereas the kcat value remained unchanged. Therefore, the precursor of EMAPII is a multi-functional protein that assists aminoacylation in normal cells and releases the functional cytokine upon apoptosis.

Phase I study of paclitaxel administered by ten-day continuous infusion

PURPOSE

Pre-clinical data have suggested that prolonged exposure to paclitaxel enhances its cytotoxicity, but various clinical trials utilizing long-term infusions of paclitaxel have been limited by unacceptable hematologic toxicity, most notably significant neutropenia. A phase I study of paclitaxel administered over 10 days, was performed to evaluate the hematologic and non-hematologic toxicities as well as to determine the maximum-tolerated dose for the 10-day infusion duration.

PATIENTS AND METHODS

Twenty-nine solid tumor patients (predominantly non-small cell lung cancer and head and neck cancer) were treated with paclitaxel at doses ranging from 5 mg/m2/day to 25 mg/m2/day administered as a 10-day continuous infusion via a pump every 21 days. Dose escalation was permitted within individual patients. Dose-limiting toxicity (DLT) was defined as grade 3 or 4 non-hematologic toxicity, ANC < or = 500 or platelet count < or = 25,000 for > or = 7 days or febrile neutropenia. The maximum tolerated dose (MTD) was defined as the highest dose level at which less than two out of six patients developed DLT. All of the patients had received prior chemotherapy; approximately two-thirds had received prior radiation as well. All patients received standard pre-medications for paclitaxel, including anti-histamines and corticosteroids. Prophylactic granulocyte colony-stimulating factor (G-CSF) was not used.

RESULTS

A total of 110 courses of paclitaxel were administered to 29 patients. The incidence of hematologic and non-hematologic toxicity was quite low among the patients treated at dose levels below 17 mg/m2/day. At higher doses, non-hematologic toxicities including arthralgias, myalgias, fatigue, nausea, stomatitis, and peripheral neuropathy were seen, although nearly all of the toxicities were less than grade 3 (NCI toxicity criteria). Hematologic toxicity mostly consisted of neutropenia and was more common at dose levels of 17 mg/m2/day or higher. Nevertheless, even at the highest dose levels (21 mg/m2/day and 25 mg/m2/day) grade 3 or 4 neutropenia occurred in only 50% of patients. Dose-limiting hematologic toxicity occurred in 2 of 4 patients treated at the 25 mg/m2/day dose level.

CONCLUSION

Paclitaxel can be safely administered as a 10-day infusion. The MTD for this schedule is 210 mg/m2. Unlike the 96-hour paclitaxel infusions, dose-reduction for myelosuppression may not be necessary because the MTD of paclitaxel when administered over a 10-day infusion is similar to the MTD of paclitaxel when infused over 3 or 24 hours.

Identification and purification of IgE-reactive proteins in German cockroach extract

Cockroaches have been implicated as a cause of respiratory allergy in urban areas worldwide. IgE-reactive German cockroach proteins were identified with molecular weights (MWs) of 90, 66, 50, 43 and 36 KD by immunoblot analysis in both immune BALB/c mice and sensitized humans. Prominent IgE-reactive proteins were purified using FPLC by ion-exchange chromatography, gel filtration and hydrophobic chromatography. The N-terminal amino acid sequence of a purified protein with a MW of 66 KD on SDS-PAGE was Val-Thr-Leu-Lys-Lys(Val)-Met-Ile-Lys-Thr-Phe-Tyr. No homologous protein was found through a search of GenBank that indicated a novel IgE-reactive protein in German cockroach extract. Another purified protein with a MW of 36 KD reacted strongly with a monoclonal antibody against Bla g 2.

Value of FDG PET in papillary thyroid carcinoma with negative 131I whole-body scan

The management of metastatic thyroid carcinoma patients with a negative 131I scan presents considerable problems. Fifty-four athyrotic papillary thyroid carcinoma patients whose 1311 whole-body scans were negative underwent 18F-fluorodeoxyglucose (FDG) PET; the purpose was to determine whether this procedure could localize metastatic sites. We also assessed its usefulness in the management of these patients.

METHODS

Whole-body emission scan was performed 60 min after the injection of 370-555 MBq 18F-FDG, and additional regional attenuation-corrected scans were obtained. Metastasis was pathologically confirmed in 12 patients and was confirmed in other patients by overall clinical evaluation of the findings of other imaging studies and of the subsequent clinical course.

RESULTS

In 33 patients, tumor had metastasized, whereas 21 patients were in remission. FDG PET revealed metastases in 31 patients (sensitivity 93.9%), whereas thyroglobulin levels were elevated in 18 patients (sensitivity 54.5%). FDG PET was positive in 14 of 15 metastatic cancer patients with normal thyroglobulin levels. In 20 of 21 patients in remission, FDG PET was negative (specificity 95.2%), whereas thyroglobulin levels were normal in 16 patients (specificity 76.1%). The sensitivity and specificity of FDG PET were significantly higher than those of serum thyroglobulin. In patients with negative 1311 scans, FDG PET detected cervical lymph node metastasis in 87.9%, lung metastasis in 27.3%, mediastinal metastasis in 33.3% and bone metastasis in 9.1%. In contrast, among 117 patients with 131I scan-positive functional metastases, 131I scan detected cervical lymph node metastasis in 61.5%, lung metastasis in 56.4%, mediastinal metastasis in 22.2% and bone metastasis in 16.2%. In all 5 patients in whom thyroglobulin was false-negative with negative antithyroglobulin antibody, PET showed increased 18F-FDG uptake in cervical lymph nodes, mediastinal lymph nodes, or both. Among patients with increased 18F-FDG uptake only in the cervical lymph nodes, the nodes were dissected in 11. Metastasis was confirmed in all, even in normal-sized lymph nodes.

CONCLUSION

FDG PET scan localized metastatic sites in 131I scan-negative thyroid carcinoma patients with high accuracy. In particular, it was superior to 131I whole-body scan and serum thyroglobulin measurement for detecting metastases to cervical lymph nodes. FDG PET was helpful for determining the surgical management of these patients.

Paclitaxel resistance in non-small-cell lung cancer associated with beta-tubulin gene mutations

PURPOSE

The mechanisms that cause chemoresistance in non-small-cell lung cancer (NSCLC) patients have yet to be clearly elucidated. Paclitaxel is a tubulin-disrupting agent that binds preferentially to beta-tubulin. Tubulins are guanosine triphosphate (GTP)-binding proteins. Beta-tubulin is a GTPase, whereas alpha-tubulin has no enzyme activity. We reasoned that polymerase chain reaction (PCR) and DNA sequencing of the beta-tubulin gene could reveal more information regarding the connection between beta-tubulin mutations and primary paclitaxel resistance.

PATIENTS AND METHODS

Constitutional genomic DNA and paired tumor DNA were isolated from 49 biopsies from 43 Spanish and six American stage IIIB and IV NSCLC patients who had been treated with a 3-hour, 210 mg/m(2) paclitaxel infusion and a 24-hour, 200 mg/m(2) infusion, respectively. Oligonucleotides specific to beta-tubulin were designed for PCR amplification and sequencing of GTP- and paclitaxel-binding beta-tubulin domains.

RESULTS

Of 49 patients with NSCLC, 16 (33%; 95% confidence interval [CI], 20.7% to 45.3%) had beta-tubulin mutations in exons 1 (one patient) or 4 (15 patients). None of the patients with beta-tubulin mutations had an objective response, whereas 13 of 33 (39.4%; 95% CI, 22.8% to 56%; P = 0.01) patients without beta-tubulin mutations had complete or partial responses. Median survival was 3 months for the 16 patients with beta-tubulin mutations and 10 months for the 33 patients without beta-tubulin mutations (P =.0001).

CONCLUSION

We have identified beta-tubulin gene mutations as a strong predictor of response to the antitubulin drug paclitaxel; these mutations may represent a novel mechanism of resistance and should be examined prospectively in future trials of taxane-based therapy in NSCLC.

Volumetric visualization of head and neck CT data for treatment planning

PURPOSE

To demonstrate the utility of volume rendering, an alternative visualization technique to surface rendering, in the practice of CT based radiotherapy planning for the head and neck.

METHODS AND MATERIALS

Rendo-avs, a volume visualization tool developed at the University of Chicago, was used to volume render head and neck CT scans from two cases. Rendo-avs is a volume rendering tool operating within the graphical user interface environment of AVS (Application Visualization System). Users adjust the opacity of various tissues by defining the opacity transfer function (OTF), a function which preclassifies voxels by opacity prior to rendering. By defining the opacity map (OTF), the user selectively enhances and suppresses structures of various intensity. Additional graphics tools are available within the AVS network, allowing for the manipulation of perspective, field of view, data orientation. Users may draw directly on volume rendered images, create a partial surface, and thereby correlate objects in the 3D scene to points on original axial slices. Information in volume rendered images is mapped into the original CT slices via a Z buffer, which contains the depth information (Z coordinate) for each pixel in the rendered view. Locally developed software was used to project conventionally designed GTV contours onto volume rendered images.

RESULTS

The lymph nodes, salivary glands, vessels, and airway are visualized in detail without prior manual segmentation. Volume rendering can be used to explore the finer anatomic structures that appear on consecutive axial slices as "points." Rendo-avs allowed for acceptable interactivity, with a processing time of approximately 5 seconds per 256 x 256 pixel output image.

CONCLUSIONS

Volume rendering is a useful alternative to surface rendering, offering high-quality visualization, 3D anatomic delineation, and time savings to the user, due to the elimination of manual segmentation as a preprocessing step. Volume rendered images can be merged with conventional treatment planning images to add anatomic information to the treatment planning process.

Intracisternal type A particle-mediated activation of the Notch4/int3 gene in a mouse mammary tumor: generation of truncated Notch4/int3 mRNAs by retroviral splicing events

The int3 oncogene was discovered as a frequent target in mouse mammary tumor virus-induced mammary tumors and encodes the intracellular domain of a Notch4/int3 protein. In one spontaneous mammary tumor, no. 9, that developed in a BALB/c mouse, we have found an insertion of a 1.2-kb sequence, consisting of a 5' long terminal repeat and gag sequences of an intracisternal type A particle (IAP) as well as an extra copy of the Notch4/int3 genomic sequences containing exons 23 and 24, into the intron between exons 24 and 25 of the Notch4/int3 gene. In this tumor, unique splicing events between the IAP and the Notch4/int3 sequences generated two types of IAP-Notch4/int3 fusion transcripts encoding two different portions of the intracellular domain of Notch4/int3 proteins: one with a RAM domain and the other without. Interestingly, these two proteins showed different subcellular localizations in a mouse mammary epithelial cell line, HC-11.