GATA-4 and Nkx-2.5 coactivate Nkx-2 DNA binding targets: role for regulating early cardiac gene expression

The cardiogenic homeodomain factor Nkx-2.5 and serum response factor (SRF) provide strong transcriptional coactivation of the cardiac alpha-actin (alphaCA) promoter in fibroblasts (C. Y. Chen and R. J. Schwartz, Mol. Cell. Biol. 16:6372-6384, 1996). We demonstrate here that Nkx-2.5 also cooperates with GATA-4, a dual C-4 zinc finger transcription factor expressed in early cardiac progenitor cells, to activate the alphaCA promoter and a minimal promoter, containing only multimerized Nkx-2.5 DNA binding sites (NKEs), in heterologous CV-1 fibroblasts. Transcriptional activity requires the N-terminal activation domain of Nkx-2.5 and Nkx-2.5 binding activity through its homeodomain but does not require GATA-4's activation domain. The minimal interactive regions were mapped to the homeodomain of Nkx-2.5 and the second zinc finger of GATA-4. Removal of Nkx-2.5's C-terminal inhibitory domain stimulated robust transcriptional activity, comparable to the effects of GATA-4 on wild-type Nkx-2.5, which in part facilitated Nkx-2.5 DNA binding activity. We postulate the following simple model: GATA-4 induces a conformational change in Nkx-2.5 that displaces the C-terminal inhibitory domain, thus eliciting transcriptional activation of promoters containing Nkx-2.5 DNA binding targets. Therefore, alphaCa promoter activity appears to be regulated through the combinatorial interactions of at least three cardiac tissue-enriched transcription factors, Nkx-2.5, GATA-4, and SRF.

Quantification of Helicobacter pylori infection: Simple and rapid 13C-urea breath test in Taiwan

The 13C-urea breath test (13C-UBT) is a non-invasive method for detecting Helicobacter pylori. This study was performed to determine the cutoff value and evaluate the sensitivity and specificity of 13C-UBT in Taiwan. 13C-Urea (100 mg of 99% 13C-labeled urea) was dissolved in 50 ml sterile water for the test. The test meal for delaying gastric emptying was 100 ml fresh milk. Patients fasted for at least 6h. A baseline breath sample was collected 5 min after they had the test meal. Two other samples were collected at 15 and 30 min after the patients ingested the 13C-urea. The test was evaluated in 352 patients after routine upper gastrointestinal endoscopy, and the urease test, culture, and histopathology were taken as the gold standards for detecting H. pylori. According to the receiver operating characteristic (ROC) curves, we chose values of 2.8 and 4.2 excess delta 13CO2 per mil as the cut-off values for 15 and 30 min, respectively, post 13C-urea. The sensitivity and specificity of 13C-UBT were 99% and 93% at 15 min, and 98% and 93% at 30 min post 13C-urea, respectively. The 13C-UBT breath test is an efficient non-invasive method of high sensitivity and high specificity for detecting H. pylori infection. We suggest that the use of fresh milk as the test meal and the detection of excess delta 13CO2 15 min after the ingestion of 13C-urea are suitable for the clinical use of 13C-UBT. This test is simple and rapid.

Nickel toxicity to human term placenta: in vitro study on lipid peroxidation

It has been reported that nickel (Ni) crosses the human placenta and produces teratogenesis and embryotoxicity. In the present study, the effects of nickel on human term placentas were investigated. In time-course experiments, placental tissue was incubated for 3, 6, 12, or 24 h with 2.5 mM Ni. The viability as determined by glucose consumption rate did not show any significant change from 3 to 12 h, whereas the permeability, lipid peroxidation, and Ni concentration were significantly increased compared to the control. In concentration-response studies, placental explants were incubated with 0.5, 1.0, 2.5, or 5 mM Ni for 12 h. The viability did not change significantly, except for 5 mM Ni, but the permeability and lipid peroxidation increased markedly in a concentration-dependent manner. Treatment with ascorbic acid or Zn decreased placental lipid peroxidation and permeability induced by Ni, but had no effect on lowering the Ni tissue content. Data show that Ni is toxic as evidenced by lipid peroxidative damage to placental membrane, and this metabolic change may be responsible for decreased placental viability, altered permeability, and potential subsequent embryotoxicity.

Effects of vitamin A pretreatment on nickel-induced lipid peroxidation and concentration of essential metals in liver, kidney and lung of mice

In the present study we report the effects of pretreatment with large doses of vitamin A (Vit A, retinol) on hepatic, renal and pulmonary lipid peroxidation, and Ni and essential metal (Fe, Cu, Zn and Ca) concentrations in mice acutely exposed to nickel. Vitamin A (250,000 IU/kg per day) was administered by oral gavage to ICR mice for 7 days. On the 8th day, NiCl2 (5 mg Ni/kg body wt.) was injected i.p. to Vit A- or vehicle-pretreated mice. Vitamin A pretreatment alone did not alter lipid peroxidation in liver, kidney and lung. Lipid peroxidation in liver, kidney and lung was increased after treatment with NiCl2 alone. The extent of lipid peroxidation levels in Vit A + Ni treated mice was enhanced in liver, but reduced in kidney and lung. The Ni concentration in these three organs was below the detection limit (0.09 microg/g) in control and Vit A-pretreated mice. The accumulation of Ni in Vit A + Ni treated mice was increased in liver, but decreased in kidney and lung compared to Ni-treated mice. The concentrations of Fe, Cu, Zn and Ca in these organs were significantly increased in Ni-treated mice. In Vit A + Ni treated mice, compared to Ni-treated mice, hepatic Fe was significantly increased while Cu, Zn and Ca levels were reduced, but still higher than those of control and Vit A-treated mice. In the kidney of Vit A + Ni treated mice, the increase of Cu, Fe, and Zn but not Ca, was reduced and not significantly different from control and Vit A-treated mice. Pretreatment with Vit A reduced the increased Fe, Cu, Zn and Ca concentration in the lung caused by Ni injection. We therefore conclude that the effect of Vit A pretreatment on Ni toxicity is organ-dependent.

Indicators of liver excretory function in patients undergoing biliary decompression for obstructive jaundice

BACKGROUND/AIMS

The recovery of liver function after biliary drainage in patients with obstructive jaundice may be different depending on the severity and duration of the obstruction. We conducted this study to determine whether there are any clinical factors that can be used to monitor the course of recovery.

METHODOLOGY

Serum and bile from 12 patients were collected for biochemical testing on the day of drainage and every 3 days for 6 days. Liver function was evaluated by the indocyanine green retention test (ICG R15) before and 6 days after decompression. Patients with an ICG R15 reduction ratio of less than 50% were considered to have a poor recovery (group 1, n = 6), while a good recovery was indicated by a reduction ratio higher than 50% (group 2, n = 6). Sequential data were compared between the groups and correlated with the results of the ICG test.

RESULTS

After drainage, the patients in group 1 had less bile acid excretion on day 3 (1.0 +/- 0.8 vs. 3.4 +/- 1.1 mmol/day, p < 0.05), a slower reduction ratio of serum bilirubin on day 3 (0.38 +/- 0.14 vs. 0.60 +/- 0.12, p < 0.05) and more biliary output on day 6 (1.11 +/- 0.25 vs. 0.60 +/- 0.25 L/day, p < 0.05). The ICG R15 reduction ratio was well correlated with the bilirubin reduction ratio, the bile volume and the amount of excreted bile acids checked on day 3 (gamma = 0.73, -0.71 and 0.74, respectively, p < 0.01).

CONCLUSIONS

The presence of choleresis implies ductular cell hyperplasia, while decreased excretion of bile acids and a slow reduction of hyperbilirubinemia represents severe liver damage. Both conditions are sequelae of prolonged obstruction; therefore, they might indicate a long and poor recovery.

Gain of muscle torque at low and high speed after isokinetic knee strengthening program in healthy young and older adults

Low-speed isokinetic exercise has been recommended to exert a maximal contraction and produce greater muscle torque than high-speed exercise in young adults. The purpose of this study was to compare the effectiveness of low- and high-speed isokinetic exercise programs for increasing muscle torque in young and elderly people. Twenty healthy elderly and 20 young subjects participated. The elderly subjects were divided into two groups. One group performed high-speed (300 degrees/s) isokinetic exercise training three times a week for the dominant-side knee extensor and low-speed (60 degrees/s) exercise for the non-dominant side for 6 weeks. The other group was trained using the reverse exercise regime. The training program for the young subjects was the same as that for the elderly groups. All subjects had their knee extensor torque evaluated with an isokinetic test before and at 2-week intervals during the training program. For young and elderly groups, both high- and low-speed isokinetic exercise training increased extensor torque in low- and high-speed tests. For the young group, low-speed exercise effectively improved muscle torque at low and high speeds. The improvement in slow muscle torque was significantly greater than that in fast muscle torque. For the elderly subjects, high-speed isokinetic exercise produced the greatest muscle torque at high speed in the first 2 weeks of training, and demonstrated a sharp increase in muscle torque in the final 2 weeks. Low-speed exercise frequently caused knee stress and the inability of some elder subjects to continue the exercises with maximal effort. Our findings indicate that high-speed exercise may be more appropriate for the elderly, and low-speed exercise may be more appropriate for younger people.

Imaging of huge lingual thyroid gland with goitre

We present the CT and MRI findings in a 75-year-old woman with a huge pathologically proven lingual thyroid which underwent goitrous degeneration. CT and MRI showed a midline, tongue-based, exophytic mass with areas of necrosis and heterogeneous contrast enhancement, as seen in large goitres in the normal thyroid gland.

Septic metastatic endophthalmitis from Klebsiella pneumoniae liver abscess: CT and MR imaging characteristics--report of three cases

Computed tomography (CT) and magnetic resonance (MR) imaging were performed in three diabetic patients with endophthalmitis and liver abscess secondary to Klebsiella pneumoniae infection. Ocular abnormalities included early uveoscleral thickening, fulminant exudative vitreous humor, and late phthisis bulbi. Characteristic imaging findings of endophthalmitis in diabetic patients with liver abscess should raise a high index of suspicion for K pneumoniae infection.

Helicobacter pylori colonization does not influence the symptomatic response to prokinetic agents in patients with functional dyspepsia

Functional dyspepsia (FD) is very common, but the pathogenesis of Helicobacter pylori leading to FD is still debated. The aim of this study was first to evaluate the impact of H. pylori colonization on the efficacy of Paspertase (a metoclopramide plus exogenous enzymes regimen for FD patients) and, second, to compare the prevalence of H. pylori infection in FD patients with the general population. Seventy-four consecutive FD patients were enrolled undergoing Paspertase treatment. The symptomatic response was evaluated according to 1-4 scales of six main dyspeptic symptoms (i.e. epigastric pain/discomfort, early satiety, heartburn, nausea/vomiting, abdominal fullness/bloating, and belching). Nine hundred and seventy healthy subjects undergoing a paid physical check-up were included to study the status of H. pylori colonization. The demographic data and basal symptom scores between 43 H. pylori-positive and 31 H. pylori-negative patients were not significantly different. Total and individual symptom scores improved significantly after 4 weeks of Paspertase therapy (P < 0.05), irrespective of H. pylori infection. The prevalences of H. pylori were very similar in FD patients and the general population (58.1 vs 58.0%, NS). In conclusion, these observations suggest that H. pylori colonization is not significant in FD patients of Taiwan while a short-term prokinetic medication is effective for these patients, irrespective of H. pylori status.

MR findings of Werdnig-Hoffmann disease in two infants

We report two infants with Werdnig-Hoffmann disease diagnosed by means of spinal MR imaging, histopathologic examination of muscle biopsy specimens, cloned DNA analysis, electrophysiological examination, and clinical history. The MR findings were consistent with previous histopathologic reports.

Pericoccygeal hidrocystoma

We report the imaging findings of pericoccygeal hidrocystoma in a 52-year-old woman. Sonography showed a large cystic lesion with internal echoes in the pericoccygeal region; it appeared as a well-defined, low-density mass on CT, and as a high-signal-intensity mass on T1- and T2-weighted MR images. Histopathologic examination revealed an apocrine hidrocystoma.

Transmission of the paralytic shellfish poisoning toxins, from dinoflagellate to gastropod

Purple clams, Hiatula diphos Linnaeus, are filter-feeding bivalves and maculated ivory shells. Babylonia areolata Link are carnivorous gastropods. Both shellfishes are popular seafood delicacies among the Taiwanese. Hiatula diphos were forced to contain gonyautoxins (GTXs) in this research by feeding them with cells of Alexandrium minutum Halim, a toxic dinoflagellate species responsible for the paralytic shellfish poisonings in Taiwan. The intoxicated purple clams of known toxicity and toxin composition were fed to B. areolata to observe the transmission and transformation of GTXs among this shellfish. It was found that the toxin composition in bivalve and gastropod were similar to that in dinoflagellate. Our data provide evidence for food-chain transmission of paralytic shellfish poisoning toxins, from dinoflagellate to gastropod through a filter-feeding bivalve. The transmitted GTX-I. -II. -III and -IV of A. minutum could only be found in the viscera of these shellfish. There was a notable degradation of GTX-I in the ivory shell that resulted in a decrease in toxicity while the total amount of toxins was accumulatively increasing.

Chromatographic analysis of polysaccharides extracted from Chinese Indocalamus tesselatus

Three fractions of polysaccharides that have high biological activity were extracted from Chinese bamboo leaves (Indocalamus Tesselatus) with 0.9% sodium chloride, 1% ammonium oxalate and 85% ethanol. Their component sugars were investigated by paper chromatography developed with n-butanol-pyridine-water (6:4:3 by vol), and by gas chromatography with crown ester stationary-phase-fused silica capillary column. Their monosaccharide compositions are different from each other with glucuronic acid, galactose, arabinose, mannose, glucose, and xylose (52, 18, 9, 7 and 6%, respectively) in one fraction, only glucuronic acid in another and glucuronic acid, fucose, arabinose and xylose (36, 31, 24 and 9%, respectively) in the third fraction. The protection effect of two polysaccharides against experimental hepatitis was studied in mice.

Ultrasound-guided fine needle aspiration biopsy in the diagnosis of pulmonary cryptococcosis

The purpose of this study was to assess the safety and reliability of ultrasound-guided fine needle aspiration biopsy (US-guided FNAB) combined with modified Papanicolaou's staining in the diagnosis of pulmonary cryptococcosis. The study included 10 patients (9 men, 1 woman, 28-70 yr). Percutaneous US-guided FNAB was performed through a puncture probe with central channel guidance (n = 8) or in a 'free-hand' manner (2), depending on the size of the lesion and the experience of the operator. Sonography disclosed homogeneously hypoechoic lesions with air bronchograms over the peripheral or central portion in nine patients, and occasional heterogeneous echogenicity with necrotic tissue without air bronchogram in one. Thirteen lesions were found on the chest radiographs of the 10 patients; these could be divided into three patterns: infiltrates (2), nodules or masses (7), and consolidation (4). Using US-guided FNAB and immediate modified Papanicolaou's stain, a diagnosis of pulmonary cryptococcosis was confirmed in nine of the 10 patients. The remaining case was proven by surgical resection. No major complications developed after US-guided FNAB. We conclude that this technique, combined with modified Papanicolaou's staining, provides a safe, rapid, and reliable method for diagnosing pulmonary cryptococcosis.

Giant arachnoid granulation mimicking dural sinus thrombosis in a boy with headache: MRI

We report MRI and angiographic findings of an unusual giant arachnoid granulation in the left sigmoid sinus in a boy with headache. Its signal intensity was lower than that of cerebral cortex on T1-weighted images and higher on T2 weighting, mimicking dural sinus thrombosis.

Ultrasound-guided small-bore Elecath tube insertion for the rapid sclerotherapy of malignant pleural effusion

BACKGROUND

Traditional pleurodesis for malignant pleural effusion is performed by large-bore chest tube insertion with the instillation of sclerosing agents after the compressed lung re-expansion and pleural fluid drainage of 100-150 ml/day. This study was carried out to evaluate the possibility of rapid sclerotherapy for malignant pleural effusions by insertion of a small-bore Elecath tube (12-French) under ultrasound guidance and intrapleural injection of bleomycin 60 IU.

METHODS

Twenty-six patients, with 28 cytopathologically proven malignant pleural effusions (two patients had bilateral pleural effusions) and receiving the insertion of the Elecath tube for drainage, were included in our series. This rapid and short-term sclerosing method was performed and completed by intrapleural injection of bleomycin when the pleural effusion had been clearly drained by the small-bore Elecath tube and the compressed lung had fully re-expanded on follow-up chest radiographs.

RESULTS

Twenty patients with 22 pleural effusions underwent the intrapleural injection of bleomycin, with the results of pleurodesis being complete response 41% (9/22), partial response 36% (8/22) and failure 23% (5/22). Interestingly, among the 17 successful procedures of pleurodesis (complete response and partial response), 71% (12) procedures could be completed within 2 days (seven within one day and five within 2 days). The remaining unsuccessful procedures carried out on six patients without the injection of bleomycin were due to a non-re-expanded lung (n = 3) and inadequate drainage (n = 3); of these, four patients also received the large-bore chest tube insertion after the removal of the Elecath tube, but the compressed lung still could not re-expand. The complications of the bleomycin injection were fever [77% (17/22)], vomiting [14% (3/22)] and hiccup [5% (1/22)].

CONCLUSION

The method of rapid sclerotherapy for malignant pleural effusions by small-bore Elecath tube is promising, with a success rate achieving 77%, usually within 2 days.

ARF is required for maintenance of yeast Golgi and endosome structure and function

ADP ribosylation factor (ARF) is thought to play a critical role in recruiting coatomer (COPI) to Golgi membranes to drive transport vesicle budding. Yeast strains harboring mutant COPI proteins exhibit defects in retrograde Golgi to endoplasmic reticulum protein transport and striking cargo-selective defects in anterograde endoplasmic reticulum to Golgi protein transport. To determine whether arf mutants exhibit similar phenotypes, the anterograde transport kinetics of multiple cargo proteins were examined in arf mutant cells, and, surprisingly, both COPI-dependent and COPI-independent cargo proteins exhibited comparable defects. Retrograde dilysine-mediated transport also appeared to be inefficient in the arf mutants, and coatomer mutants with no detectable anterograde transport defect exhibited a synthetic growth defect when combined with arf1Delta, supporting a role for ARF in retrograde transport. Remarkably, we found that early and medial Golgi glycosyltransferases localized to abnormally large ring-shaped structures. The endocytic marker FM4-64 also stained similar, but generally larger ring-shaped structures en route from the plasma membrane to the vacuole in arf mutants. Brefeldin A similarly perturbed endosome morphology and also inhibited transport of FM4-64 from endosomal structures to the vacuole. Electron microscopy of arf mutant cells revealed the presence of what appear to be hollow spheres of interconnected membrane tubules which likely correspond to the fluorescent ring structures. Together, these observations indicate that organelle morphology is significantly more affected than transport in the arf mutants, suggesting a fundamental role for ARF in regulating membrane dynamics. Possible mechanisms for producing this dramatic morphological change in intracellular organelles and its relation to the function of ARF in coat assembly are discussed.

From differentiation to proliferation: the secretory amyloid precursor protein as a local mediator of growth in thyroid epithelial cells

In various species, thyrotropin (TSH) is known to stimulate both differentiation and proliferation of thyroid follicle cells. This cell type has also been shown to express members of the Alzheimer amyloid precursor (APP) protein family and to release the secretory N-terminal domain of APP (sAPP) in a TSH-dependent fashion. In this study on binding to the cell surfaces, exogenously added recombinant sAPP stimulated phosphorylation mediated by mitogen-activated protein kinase and effectively evoked proliferation in the rat thyroid epithelial cell line FRTL-5. To see whether this proliverative effect of sAPP is of physiological relevance, we used antisense techniques to selectively inhibit the expression of APP and the proteolytic release of sAPP by cells grown in the presence of TSH. The antisense-induced inhibition was detected by immunoblot, immunoprecipitation, and immunocytochemical analyses. After the reduced APP expression and sAPP secretion, we observed a strong suppression of the TSH-induced cell proliferation down to 35%. Recombinant sAPP but not TSH was able to overcome this antisense effect and to completely restore cell proliferation, indicating that sAPP acts downstream of TSH, in that it is released from thyroid epithelial cells during TSH-induced differentiation. We propose that sAPP operates as an autocrine growth factor mediating the proliferative effect of TSH on neighboring thyroid epithelial cells.

Comparison of Supercritical Fluid and Soxhlet Extraction Methods for the Determination of Chlorothalonil from Cranberry Bog Soils

The development and validation of an analytical method to determine the concentration of chlorothalonil from cranberry bog soil using supercritical fluid extraction (SFE) are reported. A self-built supercritical fluid extractor using CO(2) as the supercritical fluid (SCF) was used. The recovery of chlorothalonil was optimized by varying extraction temperature, pressure, time (static and dynamic), organic modifiers, and SCF flow rate. This method was then compared to a Soxhlet extraction procedure. SFE had more consistent performance than the Soxhlet extraction method for the recovery of chlorothalonil from both fortified bog soils and field samples. SFE provided cleaner extracts, had shorter extraction times, and used less organic solvent than the Soxhlet extraction method. This result is consistent with other SFE methods for determining pesticides from various environmental matrices. Thus, SFE is a preferred method for the extraction of chlorothalonil from cranberry bog soil.

Lipid peroxidation in liver of mice administrated with nickel chloride: with special reference to trace elements and antioxidants

The relationship between Ni-induced hepatic lipid peroxidation (LPO) and the concentrations of Ni and trace elements was investigated in male ICR mice. The protective effects of antioxidants were also examined. Hepatic LPO and the concentrations of Ni, Fe, Cu, and Zn in the liver were enhanced after an ip injection of nickel chloride (NiCl2). Dose-response studies were conducted on male mice with different groups being injected with 50, 85, and 170 micromol Ni/kg. LPO increased significantly in a dose-dependent manner. In time-course studies, mice were administrated NiCl2 (170 micromol Ni/kg) and killed at intervals of 6, 12, 24, and 48 h after injection. Both LPO and the accumulation of Ni, Fe, Cu, and Zn in the liver showed a significantly positive time-course relationship after NiCl2 injection. At 1 h and 24 h after a single ip injection of 170 micromol Ni/kg, the mice were given an ip injection of ascorbic acid (vit C), glutathione (GSH), and selenium (Se). Vit C and GSH significantly decreased both the level of hepatic LPO and the concentration of Ni in the liver, but did not decrease the accumulation of Fe, Cu, and Zn. However, LPO in the experimental group of mice was different significantly from that in the control group. In conclusion, the results suggest that Ni-induced hepatic LPO may result from increasing the amounts of Ni, Fe, and Cu, since these elements are involved in the generation of hydroxyl radical by inducing the Fenton reaction, thus instigating the Ni-mediated hepatic LPO. The protective effects of vit C and GSH in hepatic LPO result not only from removing the oxygen reactive species, but also from decreasing the Ni concentration.

Carotid artery bifurcation: multiple-flip-angle, three-dimensional, time-of-flight MR angiographic technique

Multiple-flip-angle, three-dimensional, time-of-flight magnetic resonance (MR) angiography was performed in vitro and in vivo in the carotid artery bifurcation. Composite MR angiographic images were created from multiple data sets. Compared with images obtained with a low (20 degrees) flip angle, composite images obtained with flip angles of 20 degrees and 60 degrees demonstrated improved image quality and statistically significant improvement in signal-to-noise ratio (P < .05).

A broader role for AU-rich element-mediated mRNA turnover revealed by a new transcriptional pulse strategy

The widespread occurrence of AU-rich elements (AREs) in mRNAs encoding proteins with diversified functions and synthesized under a vast variety of physiological conditions suggests that AREs are involved in finely tuned and stringent control of gene expression. Thus it is important to investigate the regulation of ARE-mediated mRNA decay in a variety of mammalian cells in different physiological states. The tetracycline (Tet)-regulatory promoter system appears appropriate for these investigations. However, we found that efficient degradation of mRNAs bearing different AREs cannot be observed simply by blocking constitutive transcription from the Tet-regulated promoter with Tet, possibly due to saturation of the cellular decay machinery. In addition, deadenylation kinetics and their relationship to mRNA decay cannot be adequately measured under these conditions. To overcome these obstacles we have developed a new strategy that employs the Tet-regulated promoter system to achieve a transient burst of transcription that results in synthesis of a population of cytoplasmic mRNAs fairly homogeneous in size. Using this new system we show that ARE-destabilizing function, necessary for down-regulating mRNAs for cytokines, growth factors and transcription factors, is maintained in quiescent or growth-arrested cells as well as in saturation density-arrested NIH 3T3 cells. We also demonstrate that the ARE-mediated decay pathway is conserved between NIH 3T3 fibroblasts and K562 erythroblasts. These in vivo observations support a broader role for AREs in the control of cell growth and differentiation. In addition, we observed that there is a significant difference in deadenylation and decay rates for beta-globin mRNA expressed in these two cell lines. Deadenylation and decay of beta-globin mRNA in K562 cells is extraordinarily slow compared with NIH 3T3 cells, suggesting that the increased stability gained by beta-globin mRNA in K562 cells is mainly controlled at the deadenylation step. Our strategy for studying mammalian mRNA turnover now permits a more general application to different cell lines harboring the Tet-regulated system under various physiological conditions.

High frequency of deletion mutations in p53 gene from squamous cell lung cancer patients in Taiwan

Lung cancer is the leading and second-leading cause of cancer deaths among women and men in Taiwan, respectively. However, the molecular mechanisms involved in lung tumorigenesis in Taiwan remain poorly defined. A study that analyzed the mutation spectrum of the p53 tumor suppressor gene in 35 female lung cancer patients in Hong Kong showed that a high proportion of the mutations observed were deletions, suggesting the possible involvement of a distinct mutagenic factor(s) in Chinese female lung cancer patients (Y. Takagi et al., Cancer Res., 55: 5354-5357, 1995). Therefore, to gain insight into the role of the p53 tumor suppressor gene and possible etiological factors in lung tumorigenesis in Taiwan, we investigated the mutation spectra of exons 4-11 in the p53 tumor suppressor gene of 60 lung cancer patients in Taiwan. These data were also correlated with clinical pathological characteristics of patients. Lung tumors were surgically resected, genomic DNA was isolated, and their mutation spectra were examined using PCR/single-strand conformational polymorphism analysis and direct sequencing. The frequency of p53 gene mutation was 18% (11 of 60). However, distinct patterns of p53 gene mutation were observed. Seven of 11 mutations detected (64%) were deletions of 1-12 bp at G:C bp or at bp in the immediate vicinity of repetitive sequences and/or tandem repeat sequences. In addition, two patients (2 of 11, 18%) exhibited nonsense mutations. In contrast to the frequent occurrence of missense mutations in the p53 gene reported in the literature, the majority (82%) of the mutations in lung cancer patients in Taiwan were nonmissense mutations, ie., deletions and nonsense mutations. Immunohistochemical staining indicated that p53 mutations including non-in-frame deletions and nonsense mutations all resulted in no expression of p53 protein. Notably, mutations occurred more frequently in patients suffering from squamous cell carcinoma (SQ). Nine of 31 SQ patients (29%) exhibited deletions or nonsense mutations, suggesting that deletions and nonsense mutations in the p53 gene are involved in the formation of SQ in Taiwan. In addition, mutations occurred more frequently in patients with stage III or IV lung cancer. However, mutations were not correlated with patients' smoking habits. Our data suggest that p53 gene mutation involved in the formation of SQ and distinct environmental factor(s) and/or genetic factor(s) that induced specific short deletions in repeat sequences may be involved in lung tumorigenesis in Taiwan.

Cloning, sequencing and expression of a cDNA encoding bovine pancreatic deoxyribonuclease I in Escherichia coli: purification and characterization of the recombinant enzyme

The bovine pancreatic (bp-) DNase I gene has been cloned from bp-cDNA and expressed in E. coli. A polynucleotide sequence of 1295 base pairs was deduced from clones of the cDNA. The sequence showed an open reading frame which can be translated as a 282-amino acid polypeptide, including a hydrophobic signal peptide and the polypeptide of bp-DNase I. An expression plasmid was constructed by inserting into the vector pET-15b, a cDNA fragment coding for bp-DNase I ligated with a hexanucleotide coding for Met-Ala at the 5'-end. The plasmid was transformed into E. coli strain DH5alpha and the active recombinant bovine (rb-) DNase I was produced after induction of protein synthesis. From the induced culture medium, rb-DNase I was purified by chromatography on a Mono Q column. The purified rb-DNase I showed a molecular mass of 29 kDa and had the same specific activity as bp-DNase I. The NH2-terminus of rb-DNase I was Ala, not Met, and at position 19, corresponding to the carbohydrate attachment site of bp-DNase I, Asn was not glycosylated.

Normal and variant anatomy of hepatic arteries: angiographic experience

BACKGROUND

Anatomic variation of hepatic arteries is reported to occur in 25-50% of the general population. Knowledge of the existing variations is important in planning and conducting surgical or radiologic procedures in the upper abdomen, such as liver transplantation and transarterial chemo-embolization (TACE).

METHODS

Based on data from 321 patients undergoing upper abdominal arteriography, hepatic artery anatomy was analyzed and classified into three groups (single, double and multiple hepatic arteries at hepatic hilum) according to Suzuki's classification. Each group was subdivided into three types (celiac, mesenteric and mixed types) according to the origin of the hepatic arteries. The variations within each type were recorded.

RESULTS

Two hundred and sixty one patients (68.%) had single hepatic arteries. One hundred and five patients (27.6%) had double hepatic arteries and only fifteen patients had multiple hepatic arteries. All of these variants, including twenty subtypes, were identified.

CONCLUSIONS

This study, based on Suzuki's classification, provides basic data for the anatomic variations of hepatic arteries for the Chinese population in Taiwan.