A high-resolution absolute-dated late Pleistocene Monsoon record from Hulu Cave, China

Oxygen isotope records of five stalagmites from Hulu Cave near Nanjing bear a remarkable resemblance to oxygen isotope records from Greenland ice cores, suggesting that East Asian Monsoon intensity changed in concert with Greenland temperature between 11,000 and 75,000 years before the present (yr. B.P.). Between 11,000 and 30,000 yr. B.P., the timing of changes in the monsoon, as established with 230Th dates, generally agrees with the timing of temperature changes from the Greenland Ice Sheet Project Two (GISP2) core, which supports GISP2's chronology in this interval. Our record links North Atlantic climate with the meridional transport of heat and moisture from the warmest part of the ocean where the summer East Asian Monsoon originates.

[The effect of renal ischemic preconditioning on the myocardial ischemic/reperfusion injury in rabbits]

AIM

To investigate whether renal ischemic preconditioning could protect myocardium from ischemic-reperfusion injury.

METHODS

Thirty-two adult white rabbits were randomly divided into four groups: group sham operation (SO), myocardial ischemic-reperfusion (I/R), classical ischemic preconditioning (CIPC) and renal ischemic preconditioning (RIPC). Changes of left ventricular functions, myocardial infarct size, myocardial ultrastructure and cardiac arrhythmia were observed.

RESULTS

RIPC and CIPC could reduce the myocardial infarct size and the attack rate of arrhythmia (P < 0.01 vs I/R); improve the left ventricular functions (P < 0.01 vs I/R) and minimized the ultrastructure injury of I/R myocardium.

CONCLUSION

The RIPC might elicit a myocardial protection against ischemic-reperfusion injury, which is similar to the effect of CIPC.

[Construction and analysis of a genetic linkage map of soybean]

A high-density genetic map was constructed with a RILs population (NJRIKY) from a cross of two cultivated soybean Kefeng 1 and Nannong 1138-2, using RFLP, SSR, RAPD and AFLP markers. The map consists of 24 linkage groups, which include 792 genetic markers, and covers 2,320.7 cM with an average genetic distance of 2.9 cM. The higher polymorphsims between two parents were identified with SSR markers. Due to its simplicity and stability, they could be used as anchored marker to integrate different maps constructed with different genetic markers. AFLP marker system is efficient for map construction while it easily form clusters to cause big gaps in the map. A total of 21.7% of markers was found with distorted segregation in the RILs population. The high-density molecular linkage map is fundamental for gene localization, comparative genomics, and QTL mapping of important agronomic traits.

Long-term evaluation of recombinant interferon alpha2b in the treatment of patients with hepatitis B e antigen-negative chronic hepatitis B in Taiwan

The effect of interferon (IFN) on hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB) has not been fully investigated in Chinese patients. We enrolled 58 HBeAg-negative CHB Chinese patients with hepatitis B viremia in Taiwan to evaluate the response to IFN. 30 patients received recombinant IFN 5 million units 3 times weekly for 6-10 months, and 28 patients who refused IFN treatment served as controls. Rates of virological response and biochemical response were higher in the treated group at the end of treatment (57% vs 18%, P = 0.006, and 73% vs 29%, P = 0.002, respectively). Both effects were superior in the treated group at 6 months after IFN withdrawal (virological: 30% vs 7%, P = 0.06; biochemical: 47% vs 7%, P = 0.002). Improvement of liver histological activities with persistently biochemical response was found in 65% of the treated patients. After a mean of 32 months' follow-up, virological response was rarely maintained (17% vs 4%, P = 0.228) but biochemical response was better in the treated group (27% vs 4%, P = 0.039). None of the treated patients but five controls developed severe complications of CHB during the follow-up period. A larger total IFN dosage or a younger age (< or = 40 years) were associated with 'sustained' virological response. Younger age and higher baseline alanine transaminase values (> or = 120 Ul(-1)) were related to 'sustained' biochemical response.

Areca nut extract and arecoline induced the cell cycle arrest but not apoptosis of cultured oral KB epithelial cells: association of glutathione, reactive oxygen species and mitochondrial membrane potential

There are 600 million betel quid (BQ) chewers in the world. BQ chewing is a major etiologic factor of oral cancer. Areca nut (AN) and arecoline may inhibit the growth of oral mucosal fibroblasts (OMF) and keratinocytes. In this study, AN extract (100-800 microg/ml) and arecoline (20-120 microM) inhibited the growth of oral KB cells by 36-90 and 15-75%, respectively. Exposure to arecoline (> 0.2 mM) for 24 h induced G(2)/M cell cycle arrest of OMF and KB cells. Areca nut extract (> 400 microg/ml) also induced G(2)/M arrest of KB cells, being preceded by S-phase arrest at 7-h of exposure. No evident sub-G(0)/G(1) peak was noted. Marked retraction and intracellular vacuoles formation of OMF and KB cells were observed. Glutathione (GSH) level, mitochondrial membrane potential (Deltabetam) and H(2)O(2) production of KB cells were measured by flow cytometry. GSH level [indicated by 5-chloromethyl-fluorescein (CMF) fluorescence] was depleted by 24-h exposure of KB cells to arecoline (0.4-1.2 mM) and AN extract (800-1200 microg/ml), with increasing the percentage of cells in low CMF fluorescence. By contrast, arecoline (0.1-1.2 mM) and AN extract (800-1200 microg/ml) induced decreasing and increasing H(2)O(2) production (by 2',7'-dichloro- fluorescein fluorescence), respectively. Hyperpolarization of Deltabetam (increasing of rhodamine uptake) was noted by 24-h exposure of KB cells to arecoline (0.4-1.2 mM) and AN extract (800-1200 microg/ml). AN extract (100- 1200 microg/ml) and arecoline (0.1-1.2 mM) induced little DNA fragmentation on KB cells within 24 h. These results indicate that AN ingredients are crucial in the pathogenesis of oral submucous fibrosis (OSF) and oral cancer by differentially inducing the dysregulation of cell cycle control, Deltabetam, GSH level and intracellular H(2)O(2) production, these events being not coupled with cellular apoptosis.

[Studies of the correlation between fragile sites and giant panda's breeding problem]

An unique culture system has been established which can effectively indicate fragile sites induced by BrdU on giant panda chromosomes. After we cultured the lymphocytes of giant panda for 96 hours and treated it with low concentration of BrdU (10 micrograms/ml) for only a short time (4 hours), the areas of high-frequency-expressed fragile sites were successfully located on the centromeres of No. 2 and No. 12 chromosomes. After statistic analysis, we found that the frequency of fragile sites on No. 2 and No. 12 chromosomes are notably different among pandas. What is more important, the former is relative to giant pandas' breeding conditions and correlation coefficiency (r equals to -0.772). The result indicates that high frequency of fragile sites on No. 2 chromosome is unfavorable to giant panda's breeding and survival of filial generation.

Phase I clinical trial of curcumin, a chemopreventive agent, in patients with high-risk or pre-malignant lesions

Curcumin (diferuloylmethane), a yellow substance from the root of the plant Curcuma longa Linn., has been demonstrated to inhibit carcinogenesis of murine skin, stomach, intestine and liver. However, the toxicology, pharmacokinetics and biologically effective dose of curcumin in humans have not been reported. This prospective phase-I study evaluated these issues of curcumin in patients with one of the following five high-risk conditions: 1) recently resected urinary bladder cancer; 2) arsenic Bowen's disease of the skin; 3) uterine cervical intraepithelial neoplasm (CIN); 4) oral leucoplakia; and 5) intestinal metaplasia of the stomach. Curcumin was taken orally for 3 months. Biopsy of the lesion sites was done immediately before and 3 months after starting curcumin treament. The starting dose was 500 mg/day. If no toxicity > or = grade II was noted in at least 3 successive patients, the dose was then escalated to another level in the order of 1,000, 2,000, 4,000, 8,000, and 12,000 mg/day. The concentration of curcumin in serum and urine was determined by high pressure liquid chromatography (HPLC). A total of 25 patients were enrolled in this study. There was no treatment-related toxicity up to 8,000 mg/day. Beyond 8,000 mg/day, the bulky volume of the drug was unacceptable to the patients. The serum concentration of curcumin usually peaked at 1 to 2 hours after oral intake of crucumin and gradually declined within 12 hours. The average peak serum concentrations after taking 4,000 mg, 6,000 mg and 8,000 mg of curcumin were 0.51 +/- 0.11 microM, 0.63 +/- 0.06 microM and 1.77 +/- 1.87 microM, respectively. Urinary excretion of curcumin was undetectable. One of 4 patients with CIN and 1 of 7 patients with oral leucoplakia proceeded to develop frank malignancies in spite of curcumin treatment. In contrast, histologic improvement of precancerous lesions was seen in 1 out of 2 patients with recently resected bladder cancer, 2 out of 7 patients of oral leucoplakia, 1 out of 6 patients of intestinal metaplasia of the stomach, I out of 4 patients with CIN and 2 out of 6 patients with Bowen's disease. In conclusion, this study demonstrated that curcumin is not toxic to humans up to 8,000 mg/day when taken by mouth for 3 months. Our results also suggest a biologic effect of curcumin in the chemoprevention of cancer.

[Analysis of writing age of ballpoint pen ink by thin-layer chromatography]

A method based on using a thin-layer chromatographic method (TLC) for determining changes in dye of ballpoint pen ink developed with writing age. An ink drawn line of 1 cm in length was cut and placed in Eppendorf tube. Extraction was performed with 20 microL ethanol at room temperature for 15 min, and heated in steambath for 10 min. The ethanol solution(4 microL) containing the extracted dyes was then spotted on TLC plate by syringe after cooling. The ballpoint pen ink spots were eluted in a solvent of isopropyl alcohol. Using TLC scanner, the spots on TLC plate were scanned at 580 nm. The relations between ratio of peak heights and writing age were attained. Thus, the information on relative writing age can be obtained. And, the powerful evidence for identifying the age of ballpoint pen ink is provided by this method in the field of forensic science.

Oxidative stress and liver toxicity in rats and human hepatoma cell line induced by pentachlorophenol and its major metabolite tetrachlorohydroquinone

Pentachlorophenol (PCP) is a pesticide used worldwide in industrial and domestic applications. It is used extensively as biocide and wood preservatives. Metabolic studies carried out in rodents and human liver homogenates have indicated that PCP undergoes oxidative dechlorination to form tetrachlorohydroquinone (TCHQ). Free radical catalyzed tissue injury is thought to play a fundamental role in human disease. In the present study, we examined the effects of PCP and TCHQ on the induction of lipid peroxidation and liver injury in rats. In addition, the cytotoxic dose, cell death mechanisms and related gene expressions induced by PCP and TCHQ were also determined for human hepatoma cell line (Hep G2). The results indicated that more toxic effects could be observed both in rats and human hepatoma cell line treated with TCHQ than its parent compound, PCP. Oxygen species may be involved in the mechanism of TCHQ intoxication since the urinary 8-epi-PGF2alpha and AST, ALT activities can be induced by TCHQ and attenuated by vitamin E treatment. Apoptosis features were found in cells treated with TCHQ but not PCP. TCHQ-induced cell damage may issue signals for the induction of HSPs, the decrease of the bcl/bax protein ratio and the decrease of CAS gene, whereas the PCP-induced damage may not.

[Identification of quantitative trait loci associated with fruit traits in watermelon [Citullus lanantus (Thanb) Mansf] and analysis of their genetic effects]

In this study, we mapped and characterized quantitative trait loci (QTL) affecting watermelon fruit traits. A total of 118 F2 progenies derived from the cross 97103 (which is a cultivar with higher total soluble solids concentration, thin rind, susceptible to Fusarium wilt disease) x PI296341(which is a wild germplasm with lower total soluble solids concentration, thick rind, resistant to Fusarium wilt disease) were used to construct a 96-markers map in watermelon. By using interval mapping 4 QTLs for total soluble solids concentration, 5 QTLs for hardness of rind, 2 QTLs for thickness of rind, 3 QTLs for weight of simple fruit, and 6 QTLs for weight of one thousand grain seeds were identified. In addition, the explained variations, additive effects and dominance effects for all detected QTLs were analyzed.

Genomic structure and loss of heterozygosity of EPHB2 in colorectal cancer

EphB2, a member of the Eph receptor protein-tyrosine kinase family, is overexpressed in several human gastrointestinal tumors. Furthermore, the EphB2 gene is localized at 1p35-p36.1, a frequently deleted region in colon and other cancers. So, despite its overexpression in some kind of tumors, we decided to study the possibility of involvement in the EphB2 gene (EPHB2) mutation in colon cancers, because some of the well known tumor suppressor genes (e.g. p53) is overexpressed (really accumulated) in tumors. Fifty colon tumor samples of matched with their respective normal tissues, were studied for mutation of the EPHB2. Analysis of the genomic structure of EphB2 and survey of all 16 exons revealed an infrequent polymorphism (intron 2) and mutation (intron 8). Another polymorphism in exon 6, localized at nucleotide 1359 (A-->G) was found to be rather frequent in Japanese and Chinese subjects, but very rare in Caucasians. Taking advantage of this polymorphism within EPHB2, we surveyed the loss of heterozygosity (LOH) status of this gene in Japanese colorectal tumors. Among the 50 samples analyzed, 24 were informative, and LOH was found in five of the15 (33.3%) informative rectal cancer cases. Mutation analysis covering all 16 exons in the remaining allele did not reveal any mutations. Thus, EPHB2 is not a classical tumor suppressor gene.

Genomic structure of human alpha-pix, and variable deletions in a poly (T) tract in gastric cancer tissue

PAK-interacting exchange factor (PIX) has been reported to mediate the recruitment of PAK into focal adhesions and activate Rac, thus creating a feedback loop that stimulate PAK and other targets. This pathway is thought to be related to cellular changes, such as transformation and migration, that are often encountered in cancer cells. Here, we report the genomic structure of alpha-PIX, one of the PAK- interacting exchange factors, including the identification of the promoter region, which consisted 772 amino acids in 22 exons, spanning about 100 kb on genome of X chromosome. All splice sites conformed to the GT-AT rule. To investigate the role of alpha-PIX in carcinogenesis, we screened 60 cases of gastric cancer for mutations and polymorphisms using an intron-primer that covered all the exons, but no mutations or polymorphisms were found in the coding region. However an 18 bp repeat of thymidine tract was present in 50 bp downstream from exon 12 and the deletion of variable numbers of mononucleotide repeats was observed in seven out of the 60 gastric cancer tissue specimens that were examined. These seven cases all exhibited a mutator phenotype, suggesting that the deletions are passenger mutations. Thus our results revealed that alpha-PIX probably does not play any primary role in human gastric carcinogenesis.

Griseofulvin potentiates antitumorigenesis effects of nocodazole through induction of apoptosis and G2/M cell cycle arrest in human colorectal cancer cells

In this study, we demonstrate that apoptosis and G2/M cell cycle arrest were easily induced by treatment with the oral-antifungal agent, griseofulvin (GF). The mechanisms of GF-induced G2/M arrest were characterized as (a) induction of abnormal mitotic spindle formation, (b) elevation of cyclin B1/cdc2 kinase activity and (c) down-regulation of myt-1 protein expression. On the other hand, caspase 3 activation, Bcl-2 hyperphosphorylation and inhibition of the normal function of Bcl-2 associated with Bax were demonstrated to be the mechanisms of GF-induced apoptosis. DNA fragmentation and flow cytometry analyses demonstrated that combined treatment of GF with the cancer chemotherapeutic agent, nocodazole (ND), strongly potentiates the apoptotic effect and arrest of the G2/M cell cycle in 5 types of human cancer cells, but not in normal human keratinocytes (#76 KhGH). The combined treatment of GF and ND triggered the polymerization of purified tubulin in HT 29 but not in #76 KhGH cells. To further confirm these observations, the therapeutic efficacy was further examined in vivo by treating athymic mice bearing COLO 205 tumor xenografts, with GF (50 mg/kg), ND (5 mg/kg) or GF + ND. Combined treatment of GF and ND significantly enhanced the effect of ND, and led to cessation of tumor growth. These results suggest that chemotherapeutic agents (such as ND) administered in the presence of GF might provide a novel therapy for colorectal cancer.

[Dynamic observation on imbalance of dynamic and static forces and degenerated cervical intervertebral disc in rats]

OBJECTIVE

To study the relation between biomechanical imbalance and the degree and course of degeneration of cervical intervertebral disc in rats.

METHODS

Sixty SD rats, 8 months old, were randomly divided into 6 groups, the control and model groups of 3, 5, 7 months, 10 in each group. The cervical disc dynamic and static forces imbalance of degeneration model was established to assess the degree of degeneration as well as the content some inflammatory mediators (prostaglandin E2, 6-keto-prostaglandin F1 alpha) and collagenase (MMP-1) activity.

RESULTS

(1) In 3 months model group and 5 months control group, fibrous ring of intervertebral disc showed some fissure and slight irregular arrangement, nucleus pulposus shrunken or became smaller, mild herniation of nucleus pulposus was seen in some disc. The nucleus pulposus of intervertebral disc in 5 months model group was fibrosed completely and the disc in 7 months model group herniated or became osteophytosis. (2) Compared with the control group of same time period, MMP-1 was increased significantly in the 5 months and 7 months model groups (P < 0.05), and prostaglandin E2 and 6-keto-prostaglandin F1 alpha elevated in the model groups (P < 0.05, P < 0.01). (3) Comparison between model groups, MMP-1 activity in 5 months and 7 months groups was higher than that in the 3 months group (P < 0.05), and 6-keto-prostaglandin F1 alpha was higher in 7 months group than that in 3 months group (P < 0.05).

CONCLUSION

Cervical intervertebral disc undergoes a progressive degenerating process. By breaking the dynamic-static balance of neck in rats could accelerate the progression of degeneration. The fact could be used to elucidate the theory of pathogenesis of cervical spondylopathy, dynamic force imbalance in priority and static force imbalance in predominance.

TAG-1-deficient mice have marked elevation of adenosine A1 receptors in the hippocampus

TAG-1 is a neural recognition molecule in the immunoglobulin superfamily that is predominantly expressed in the developing brain. Several lines of evidence suggest that TAG-1 is involved in the outgrowth, guidance, and fasciculation of neurites. To directly assess the function of TAG-1 in vivo, we have generated mice with a deletion in the gene encoding TAG-1 using homologous recombination in embryonic stem cells. Gross morphological analysis of the cerebellum, the spinal cord, and the hippocampus appeared normal in TAG-1-deficient mice. However, TAG-1 (-/-) mice showed the upregulation of the adenosine A1 receptors determined by [(3)H]cyclopentyl-1,3-dipropylxanthine in the hippocampus, and their greater sensitivity to convulsant stimuli than that in TAG-1 (+/+) mice. We suspect that the subtle changes in neural plasticity induced by TAG-1 deficiency during development cause the selective vulnerability of specific brain regions and the epileptogenicity in TAG-1 (-/-) mice.

Griseofulvin potentiates antitumorigenesis effects of nocodazole through induction of apoptosis and G2/M cell cycle arrest in human colorectal cancer cells

In this study, we demonstrate that apoptosis and G2/M cell cycle arrest were easily induced by treatment with the oral-antifungal agent, griseofulvin (GF). The mechanisms of GF-induced G2/M arrest were characterized as (a) induction of abnormal mitotic spindle formation, (b) elevation of cyclin B1/cdc2 kinase activity and (c) down-regulation of myt-1 protein expression. On the other hand, caspase 3 activation, Bcl-2 hyperphosphorylation and inhibition of the normal function of Bcl-2 associated with Bax were demonstrated to be the mechanisms of GF-induced apoptosis. DNA fragmentation and flow cytometry analyses demonstrated that combined treatment of GF with the cancer chemotherapeutic agent, nocodazole (ND), strongly potentiates the apoptotic effect and arrest of the G2/M cell cycle in 5 types of human cancer cells, but not in normal human keratinocytes (#76 KhGH). The combined treatment of GF and ND triggered the polymerization of purified tubulin in HT 29 but not in #76 KhGH cells. To further confirm these observations, the therapeutic efficacy was further examined in vivo by treating athymic mice bearing COLO 205 tumor xenografts, with GF (50 mg/kg), ND (5 mg/kg) or GF + ND. Combined treatment of GF and ND significantly enhanced the effect of ND, and led to cessation of tumor growth. These results suggest that chemotherapeutic agents (such as ND) administered in the presence of GF might provide a novel therapy for colorectal cancer.

Comparison of clinical, virologic and pathologic features in patients with acute hepatitis B and C

BACKGROUND AND AIMS

The clinical outcomes of adult-acquired acute infection of hepatitis C virus (HCV) and hepatitis B virus (HBV) are quite different. In order to compare the clinical, biochemical, virologic and pathologic pictures in these two groups of patients, we enrolled 22 adult patients with acute hepatitis C and 16 adult patients with acute hepatitis B, on whom liver biopsies were performed within 3 months of acute onset of the illness.

RESULTS

The results showed that a significantly younger age, a higher ratio of the clinical symptoms of jaundice, nausea, vomiting, and poor appetite, a higher mean serum level of alanine transaminase, aspartate transaminase, and total bilirubin were present in patients with acute hepatitis B patients than in those with acute hepatitis C (P < 0.05). There was a significantly higher degree of periportal inflammation and total necro-inflammatory activity in the acute hepatitis B patients (P = 0.002 and 0.049, respectively). Fifteen (68.2%) of the 22 patients with acute hepatitis C had detectable serum HCV-RNA, but only two (14.3%) of the 14 tested patients with acute hepatitis B had detectable serum HBV-DNA, detected by using the branched DNA signal amplification assay. Eighteen (82%) of the 22 acute hepatitis C patients and none of the 16 acute hepatitis B patients progressed into a chronic hepatitis stage (P < 0.001).

CONCLUSION

The manifestations of mild clinical symptoms, lower mean serum transaminases and bilirubin levels, a lesser degree of histological periportal necroinflammation, and more patients with a high circulatory viral load among the acute hepatitis C patients, may lead to more of that group developing chronicity than patients with acute hepatitis B.

[Microsatellite marker analysis of a soybean recombinant inbred line NJRIKY]

The prerequisite of genomic research such as genetic mapping is construction of a suitable segregating population and its reasonable evaluation before use. A recombinant inbred line (RILs), NJRIKY, was constructed through a cross between Kefeng 1 and Nannong 1138-2. The present study was focused on evaluation of genetic structure of the RILs through the simple sequence repeats (SSRs) analysis. A total number of 138 pairs of SSRs primers covering the whole soybean genome were randomly selected for polymorphic analysis between two parents. 86 pairs of which were polymorphic and polymorphic rate is up to 62.32%. 90 polymorphic loci were found. Further analysis with polymorphic SSRs loci on the sampled lines indicated that not only segregation of most SSRs loci conformed to the ratio of 1:1, but also almost each sampled line tended to homozyge. The distribution of genotypic composition was normal. The population is ideal for genetic mapping and other genomic research.

Seroetiology of acute lower respiratory infections among hospitalized children in Beijing

BACKGROUND

Little is known of the etiology of childhood acute lower respiratory infections in China, where the use of antimicrobials is indiscriminate. Trials to change such a policy require etiologic data, especially on the bacteria most relevant to these common diseases.

METHODS

One hundred consecutive infants and children from 3 months to 14 years of age with symptoms and signs compatible with acute lower respiratory infections were studied prospectively in the largest pediatric hospital in Beijing from February to May, 1997. Blood culture, thorax radiography and paired sera for 20 microbiologic assays were taken, and the course of illness was monitored uniformly. Disease severity was graded.

RESULTS

In 24 cases there was evidence only of bacterial etiology, and in 5 solely viral agents were found; 3 children probably had a mixed bacterial-viral infection. Surprisingly no pneumococcal infection was detected, Mycoplasma pneumoniae (n = 21), Haemophilus influenzae type b (n = 8) and Chlamydia pneumoniae (n = 7) being the dominant bacteria. All children recovered.

CONCLUSIONS

Routine use of antimicrobials for these patients seems unjustified. Serologic evidence for the H. influenzae type b etiology is encouraging in terms of vaccination, but confirmatory studies are needed.

[QTLs mapping of some agronomic traits of soybean]

A recombinant inbred population of soybean was developed from a intraspecies cross of Kefeng1 and Nannong 1138-2. A genetic linkage group of soybean genome was constructed, which composed of 22 linkage groups, included 302 loci, covered 2,363.8 cM. The interval mapping was used to identify quantitative trait loci (QLTs) associated with ten important agronomic traits in the RIL population. The results indicated that thirty-four QTLs were detected for the ten traits associated with yield and seed quality. We conclude that QTL analysis offers a useful tool for the genetic improvement of soybean cultivars.

Compaction of ordered dithered images with arithmetic coding

Ordered dither is considered to be a simple and effective method among all halftoning techniques. In this paper, compaction of ordered dithered images using arithmetic coding is studied. A preprocessor referred to as pixel interleaving (i.e., grouping pixels with similar dithering thresholds) is employed in such a way that dithered images can be efficiently coded with the JBIG1 code and high compressibility can be achieved. Experimental results reveal that the four-pixel interleaving achieves the best compression performance.

Cell encapsulation with alginate and alpha-phenoxycinnamylidene-acetylated poly(allylamine)

In general, microcapsules prepared from alginate and polycations lack mechanical strength because the interaction between alginate and polycations is ionic instead of covalent, which represents a much stronger bond. To increase the mechanical strength of the capsule, we prepared photosensitive microcapsules that could form covalent bonds between polymers in the capsular membrane by light irradiation. Two types of photosensitive poly(allylamine), with 5% and 10% of amino groups modified by alpha-phenoxycinnamylidene acetylchloride, were synthesized. Both photopolymers exhibited an absorption maximum at 325 nm and were capable of crosslinking upon light exposure. These photosensitive polymers were used for the preparation of microcapsules. The capsules formed from this photosensitive poly(allylamine) and alginate were strengthened significantly by light irradiation. Only 28% of the microcapsules prepared from the 5%-modified photopolymer fractured after 48 h of shaking at 150 rpm. This fracture percentage is much lower when compared with the 60% of capsules fractured when prepared from the untreated poly(allylamine). By using poly(allylamine) at 10% modification, the mechanical strength was improved only slightly, with 26% of capsules fractured. Analysis of the permeability test indicated that the photo-crosslinked capsular membrane was freely permeable to cytochrome c and myoglobin, but less permeable to serum albumin. The encapsulation method was used to entrap and culture IW32 mouse leukemia cells. The cells proliferated to a density of about 1.1 x 10(7) cells/mL in the capsules after 7 days of cultivation. Concurrently, the concentration of erythropoietin in the microcapsules increased to 800 mU/mL. This new encapsulation technique has great potential in the application of a bioindustrial cell-culturing process.

Ketoconazole induces G0/G1 arrest in human colorectal and hepatocellular carcinoma cell lines

Ketoconazole is an oral-antifungal agent that has been used worldwide in the treatment of some hormone-dependent human cancer. In this study, we demonstrated that ketoconazole (20 microM) induced various types of human cancer cell growth arrest in the G0/G1 phase. Our results revealed that ketoconazole-induced growth arrest was more profound in COLO 205 and Hep G2 (with wild-type p53) than in HT 29 (p53 His(273) mutant) and Hep 3B (with deleted p53) cells. The protein levels of p53, p21/Cip1, and p27/Kip1 were significantly elevated by ketoconazole (10 microM) treatment in COLO 205 but not in HT 29 cells. The ketoconazole-induced G0/G1 phase arrest in COLO 205 cells was attenuated by p53-specific antisense oligodeoxynucleotides (20 microM) treatment. These results suggested that the p53-associated signaling pathway is involved in the regulation of ketoconazole-induced cancer cell growth arrest. By Western blot analysis, we demonstrated that cyclin D3 and CDK4 protein but not other G0/G1 phase regulatory protein levels were decreased by ketoconazole-treatment in both COLO 205 and HT 29 cells. Our study provides the basis of molecular mechanisms for ketoconazole in growth inhibition of human cancer cells and such results may have significant applications for cancer chemotherapy.