Assessment of the cryoablation margin using MRI-CT fusion imaging in hepatic malignancies

AIM

To demonstrate the feasibility of magnetic resonance imaging (MRI)-computed tomography (CT) fusion imaging for the assessment of the ablative margin after cryoablation in hepatic malignancies.

MATERIALS AND METHODS

This retrospective study analysed 35 patients with 47 liver tumours treated with CT-guided cryoablation. Fusion images of pre-ablation MRI and intraoperative CT data were created on a workstation. Minimal ablative margin (MAM) assessment was categorised into three groups: (I) MAM <0 mm (tumour protruded through the ablation zone), (II) MAM 0-5 mm, and (III) MAM ≥5 mm. Local tumour progression (LTP) was assessed during follow-up.

RESULTS

MRI-CT fusion imaging was successfully achieved in 46 (97.9%) of 47 lesions. LTP was detected in 67.4% (31/46) of cases. Twenty-four (77.4%) of 31 LTPs occurred in the subcapsular region of the liver. Using fusion images, the MAM was classified as groups I, II, and III in 18, 25, and three tumours, respectively. In group I, LTP was found in 15 (83.3%) of 18 lesions, whereas in group II, LTP was detected in 16 (64%) of 25 lesions. The cumulative LTP rate in group II was significantly lower than that in group I (p=0.012).

CONCLUSION

Pre-ablation MRI and intraoperative CT fusion imaging is feasible and useful for evaluating the MAM of cryoablation in hepatic malignancies.

[Diagnostic and therapeutic values of interphase fluorescence in situ hybridization in B-cell lymphomas: a clinicopathologic analysis of 604 cases]

Objective: To investigate the feasibility and value of interphase fluorescence in situ hybridization (FISH) in the pathological diagnosis, differential diagnosis and therapeutic assessment of B-cell lymphomas. Methods: The cohort included 604 cases of B-cell lymphoma which were collected at West China Hospital from May 2010 to December 2016.And all were subjected to interphase FISH using 11 break apart or fusion probes (MYC, bcl-2, bcl-6, IRF4, MYC/IgH, bcl-2/IgH, CCND1/IgH, IgH, API2/MALT1, p53/ATM, and D13S319/CEP12). Results: The median age of the 604 B-cell lymphoma patients was 47.7 (aged 2-90) years including 372 men and 232 women. All the cases was divided into 463 large B cell lymphomas(LBL) and 141 small B cell lymphomas, and the total interphase FISH positive rate was 59.8% (361/604). Among the 463 LBL, 12.5% (58/463), 9.5% (44/463) and 2.2% (10/463) of cases showed MYC, bcl-6 and bcl-2 gene rearrangements respectively; and 363 diffuse large B cell lymphoma (DLBCLs) were reclassified as germinal center B-cell (GCB) subtype (38.6%, 140/363) and non-GCB subtype (61.4%, 223/363) by Hans algorithm. The rearrangement rates in GCB and non-GCB DLBCL were 45.7%(64/140)and 21.5%(48/223; P=0.001), respectively. Compared to the non-GCB DLBCL, GCB DLBCL showed higher MYC and bcl-2 gene rearrangements (P=0.001). Eleven (2.4%, 11/463) cases had MYC and bcl-6 or bcl-2 gene rearrangement (double-hit lymphoma); one (0.2%, 1/463) case had MYC, bcl-6 and bcl-2 gene rearrangements (triple-hit lymphoma); two (0.4%, 2/463) cases had bcl-2 and bcl-6 gene rearrangements. MYC translocation and MYC/IgH fusion were detected in 94.2%(81/86) and 83.7%(72/86) cases of Burkitt lymphomas. IRF4 rearrangement was detected in two cases of IRF4+ LBCL. Genetic abnormalities were detected in 9/19, 100%(29/29), 30.8%(12/39) and 68.5%(37/54) cases of follicular lymphoma, mantle cell lymphoma, MALT lymphoma and chronic lymphocytic leukemia, respectively. Conclusions: Interphase FISH can rapidly and accurately detect the genetic changes in B-cell lymphomas. Different genetic changes are specifically valuable to the diagnosis, differential diagnosis, prognosis evaluation and treatment guidance of various B-cell lymphomas.

[Expression and significance of c-fos in resistant cell line TU177/VCR of larynx squamous cell carcinoma]

Objective: To explore the effect of c-fos on multidrug resistance of laryngeal cancer TU177 cells. Method: Increasing drug concentration gradient is adopted to establish the stability of the laryngeal cancer drug resistance in cell line; RT-PCR and Western blot were used to detect difference of the c-fos between TU177 and TU177/VCR cells; plasmids with human c-fos knockdown or over expression were transfected into TU177/VCR and TU177 cells respectively, and the effects of different treatment on cell proliferation were investigated with MTT. Results: The drug resistance of TU177/VCR cells was 26.25-fold in vincristine (VCR), 7.33-fold in Paclitaxel (TAX), 2.41 in cisplatin (DDP), and 5.50 in 5-fluorouracil (5-FU), comparing with TU177( P<0.05). The TU177/VCR cells had significantly higher c-fos expression compared to TU177 cells( P<0.05). The results showed that the IC(50) values of 5-FU for the NC group and c-fos shRNA group were (306.2±6.3)μmol/L and (81.3±3.9)μmol/L, respectively, which was decreased by 73% in the c-fos shRNA group compared to that in the NC group (P<0.05). Similarly, the results showed that the IC(50) values for 5-FU were (55.3±9.4) μmol/L in NC group and (288.1±7.3)μmol/L in c-fos WT group, which was increased 5.21-fold in c-fos WT cells. Conclusion: C-fos plays important role in multidrug resistance of larynx cancer cell TU177/VCR, and might become a new molecular target for laryngeal cancer treatment.

[FAT1 inhibits cell proliferation of esophageal squamous cell carcinoma through regulating the expression of CDK4/CDK6/CCND1 complex]

Objective: To explore the expression of FAT1 in esophageal squamous cell carcinoma (ESCC) tissues, and its effect on cell proliferation. Methods: The expression levels of FAT1 protein in human ESCC tissues and matched adjacent normal tissues were determined by immunohistochemistry (IHC). Lentivirus based knockdown of FAT1 was carried out in YSE2 and Colo680N cell lines and 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) assays was performed to examine the effect of FAT1 on the proliferation of these ESCC cells. Colony formation assay was used to detect the colony formation ability. Flow cytometry was performed to analyze the cell cycle and apoptosis. The expression levels of cell cycle markers in FAT1 knock out ESCC cell lines were detected by real-time quantitative reverse transcription polymerase chain reaction(qRT-PCR) and Western blot. Results: The relative expression of FAT1 in ESCC tissues was 66.97±21.53, significantly lower than 78.13±16.76 of adjacent normal tissues(P<0.05). Knockdown of FAT1 promoted cell proliferation and colony formation. In YSE2 cell, the division time in negative control (NC) group was (1 570±51) min, significantly longer than (1 356±31) min in shFAT1 group. In Colo680N cell, division time in NC group was (1 532±53) min, significantly longer than (1 290±30) min in shFAT1 group (P<0.05). Knockdown of FAT1 promoted G1-to S-phase transition and resulted in the upregulation of CDK4/CDK6/CCND1. Conclusion: FAT1 inhibits the proliferation and G1-to S-phase transition of ESCC cells through regulating the protein expression of CDK4/CDK6/CCND1 complex.

Effects of sacral nerve stimulation with acupuncture on gut transit time and c-kit expression in colon of rats with slow transit constipation

Sacral nerve stimulation (SNS) is an alternative surgical approach to alleviate fecal incontinence and constipation. This study aimed to explore the effects and underlying mechanisms of SNS with acupuncture on gut transit time and colon c-kit protein expression in rats with slow transit constipation (STC). Fifty Sprague-Dawley rats were randomly divided into five groups: blank control, SNS, Mosapride, sham SNS, and STC model control group. The STC model was established by subcutaneous injection of morphine. Each group was treated over a 15-day period. Gut transit time was measured 1 day before the treatment started and after 5, 10, and 15 days of treatment. After the 15-day treatment, animals were sacrificed and colonic tissues were collected for analysis of c-kit protein expression, using western blot analysis. We found significant differences in gut transit time in the SNS group compared with the Mosapride group after 5 (P = 0.001) and 10 (P = 0.004) days of treatment. After 15 days of treatment, there were no differences in gut transit time among the SNS, Mosapride, and blank control groups. However, significant differences were observed when comparing the SNS and Mosapride groups with the STC model and sham SNS groups. A decreased c-kit protein expression was observed in the STC model control, sham SNS, and Mosapride groups, compared with the SNS group (P = 0.001). Our data indicate that SNS can decrease gut transit time and increase the expression of c-kit protein in rats with STC to improve colon transit function.

Effects of maturity stages on the nutritive composition and silage quality of whole crop wheat

The changes in yields and nutritive composition of whole crop wheat (Triticum aestivum L.) during maturation and effects of maturity stage and lactic acid bacteria (LAB) inoculants on the fermentation quality and aerobic stability were investigated under laboratory conditions. Whole crop wheat harvested at three maturation stages: flowering stage, milk stage and dough stage. Two strains of LAB (Lactobacillus plantarum: LAB1, Lactobacillus parafarraqinis: LAB2) were inoculated for wheat ensiling at 1.0×10⁵ colony forming units per gram of fresh forage. The results indicated that wheat had higher dry matter yields at the milk and dough stages. The highest water-soluble carbohydrates content, crude protein yields and relative feed value of wheat were obtained at the milk stage, while contents of crude fiber, neutral detergent fiber and acid detergent fiber were the lowest, compared to the flowering and dough stages. Lactic acid contents of wheat silage significantly decreased with maturity. Inoculating homofermentative LAB1 markedly reduced pH values and ammonia-nitrogen (NH₃-N) content (p<0.05) of silages at three maturity stages compared with their corresponding controls. Inoculating heterofermentative LAB2 did not significantly influence pH values, whereas it notably lowered lactic acid and NH₃-N content (p<0.05) and effectively improved the aerobic stability of silages. In conclusion, considering both yields and nutritive value, whole crop wheat as forage should be harvested at the milk stage. Inoculating LAB1 improved the fermentation quality, while inoculating LAB2 enhanced the aerobic stability of wheat silages at different maturity stages.

Polymorphisms in the promoter of the CD14 gene and their associations with susceptibility to pulmonary tuberculosis

Although the role of CD14 in recognizing Mycobacterium tuberculosis is well-understood, the possible role of polymorphisms in susceptibility to develop tuberculosis remains unclear. This study evaluates whether there is an association of polymorphisms within the promoter of the CD14 gene with susceptibility to pulmonary tuberculosis. In a case-control study, we genotyped the eight known single nucleotide polymorphisms SNPs within the promoter of the CD14 gene of 698 Han Chinese subjects. Statistically significant differences between tuberculosis patients and healthy controls were found for G-1619A, T-1359G, A-1145G, and C-159T. The haplotype-GGGT, composed of these four SNPs, exhibited a significant association with the disease. Furthermore, expression levels of soluble CD14 were significantly higher in tuberculosis patients with the GGGT haplotype than with other haplotypes, while IgE expression levels were significantly reduced. Our results suggest that these four SNPs within the promoter of the CD14 gene are associated with susceptibility to pulmonary tuberculosis.

Evaluation of perennial pasture legumes and herbs to identify species with high herbage production and persistence in mixed farming zones in southern Australia

Ninety-one perennial legumes and herbs (entries) from 47 species in 21 genera were evaluated at sites in New South Wales, South Australia and Western Australia over 3 years from 2002 to 2005 to identify plants with superior herbage production, persistence and the potential to reduce ground water recharge. Evaluation was undertaken in three nurseries (general, waterlogged soil and acid soil). Medicago sativa L. subsp. sativa (lucerne) cv. Sceptre was the best performing species across all sites. In the general and acid soil nurseries, Cichorium intybus L. (chicory) cv. Grasslands Puna was the only species comparable with Sceptre lucerne in terms of persistence and herbage production. Trifolium fragiferum L. cv. Palestine and Lotus corniculatus L. SA833 were the best performing species on heavy clay soils prone to waterlogging. Three Dorycnium hirsutum (L.) Ser. accessions persisted well on acid soils, but were slow to establish. Short-lived perennial forage legumes, such as Onobrychis viciifolia Scop. cv. Othello, and three Hedysarum coronarium L. entries, including cv. Grasslands Aokou, had high herbage production in the first 2 years and may be suitable for short-term pastures in phased pasture-crop farming systems. T. uniflorum L. and M. sativa subsp. caerulea SA38052 were highly persistent and could play a role as companion species in mixtures or ground cover species for undulating landscapes. Cullen australasicum (Schltdl.) G.W. Grimes SA4966 and Lotononis bainesii Baker cv. Miles had poor establishment, but were persistent. Chicory, T. fragiferum and L. corniculatus were identified as species, other than lucerne, with the most immediate potential for further selection to increase the diversity of perennial legumes and herbs adapted to southern Australian environments.

Field evaluation of perennial grasses and herbs in southern Australia. 1. Establishment and herbage production

To review pasture species for regions with 465–680 mm average annual rainfall, 22 perennial grasses and herbs were evaluated for pasture establishment and productivity in four states at seven locations where the arrest of groundwater recharge is considered necessary to ameliorate dryland salinity. Species represented introduced and native, temperate and subtropical grasses, chicory (Cichorium intybus L.) and plantain (Plantago lanceolata L.). This report describes establishment and yield; the following paper describes persistence and root characteristics. Yields were measured over 2–3 years except at one site, which suffered severe drought. Perennial ryegrass (Lolium perenne L., cv. Avalon) and tall fescue (Festuca arundinacea Schreb. = syn. Lolium arundinaceum. (Schreb.) Darbysh., cvv. AU Triumph and Resolute MaxP), cocksfoot (Dactylis glomerata L., cv. Porto) and phalaris (Phalaris aquatica L., cv. Holdfast and Australian) were the most productive species, with dry matter (DM) yields of 13.6–15.1 t/ha. For summer growth, Porto and Rhodes grass (Chloris gayana Kunth, cv. Katambora) were the most productive species; relative to Australian in summer, Porto and Katambora produced 41% and 26% more DM, respectively (95% confidence). Perennial ryegrass (cv. Avalon), tall fescue (cv. Resolute MaxP) and chicory (cv. Grouse) were particularly valuable for autumn growth; Avalon was 30% more productive than Australian. Tall fescue (cv. Resolute MaxP) was 32% more productive than Australian in winter. Avalon and AU Triumph were the most productive grasses and herbs in spring. Based on natural rainfall over the 2–3 years of measurement, the mean water use productivity, ignoring any runoff, was 10.5 kg DM/ha.mm for the three most productive species. Apart from kangaroo grass (Themeda triandra Forssk), native grasses gradually established, but over a prolonged period weeping grass (Microlaena stipoides (Labill.) R.Br., cv. Wakefield) was the most rapid. Perennial ryegrass, tall fescue, cocksfoot and phalaris maintained productive yields across a diverse range of soils and climates. Exploration of the diversity within these species in a nationally coordinated program of genetic improvement appears warranted for improving reliability and expanding the zone of adaptation.

Field evaluation of perennial grasses and herbs in southern Australia. 2. Persistence, root characteristics and summer activity

Field experiments were carried out at seven sites in southern Australia from 2002 to 2006 to measure changes in plant frequency, root characteristics and summer activity for a range of grass and herb species or cultivars. Annual rainfall during the experimental period was on average 75 mm lower than the long-term average. Plant frequency differed significantly between species and between sites. Temperate grasses generally had higher frequencies than subtropical grasses, native grasses and herbs. Cocksfoot (Dactylis glomerata cvv. Currie, Porto), tall wheat grass (Thinopyrum ponticum cv. Dundas), winter-active tall fescue (Festuca arundinacea cvv. Fraydo, Resolute MaxP) and phalaris (Phalaris aquatica cvv. Atlas PG, Australian) were the most persistent of the temperate perennial species over the experimental period. The frequency of most cultivars declined from year 2 to year 4 after establishment, but the frequency of kikuyu (Pennisetum clandestinum cv.Whittet) and wallaby grass (Austrodanthonia richardsonii cv. Taranna) increased by over 5% from year 2 to year 3, and cocksfoot (cv. Currie) increased from year 3 to year 4. At two sites where measurements were made, there were significant differences in rooting depth between species. Whittet kikuyu was the deepest among all species with a rooting depth of up to 2 m, followed by phalaris, tall fescue, grazing brome (Bromus stamineus) and tall wheat grass. Root density was affected by plant genotype and soil structure. Root density of the species varied significantly in the subsoil (0.1–1.1 m) and deeper subsoil (1.1–2 m) but not in the topsoil (0–0.1 m). Green-leafiness over summer was generally higher for subtropical grasses, native grasses, herbs and some summer-active temperate grasses, than most temperate grasses with high summer dormancy.

A novel nude mice model of human extranodal nasal type NK/T-cell lymphoma

A novel nude mice model of human extranodal nasal type NK/T-cell lymphoma was established by subcutaneously implanting the sample taken from the patient with secondary extranodal nasal type NK/T-cell lymphoma of the stomach into the right axillary region of a BALB/c (nu/nu) nude mouse. This model had been successfully transplanted in vivo for thirty-two generations with a stable growth cycle. The survival rates of both resuscitation and transplantation were 100%. Histologically, the tumor cells were medium to large size and arranged in sheets, with a little mesenchyma, and disseminated almost in all passages of the lymphoma-bearing nude mice. Immunologically, the tumor cells were positive for CD56, cytoplasmic CD3, granzyme B or TIA-1 and LMP1, sometimes for CD8 but negative for surface CD3, CD7, CD20 and CD1a. EBER1/2 was found. No T-cell receptor gamma gene rearrangement was detected in the transplanted tumors. Furthermore, both human sequencing-tagged sites SY14 and Y chromosome were detected by PCR or fluorescent in situ hybridization, respectively, in the transplanted tumor. The transplanted tumor in this novel nude mice model maintained the essential features of human extranodal nasal type NK/T-cell lymphoma, and it would be an ideal tool in vivo for further research of the tumor.

Cullen australasicum (syn. Psoralea australasica): a review and some preliminary studies related to its potential as a low rainfall perennial pasture legume

This paper reviews the morphology, establishment, herbage quality, grazing tolerance, palatability, anti-nutritional compounds and rhizobial symbiosis of Cullen australasicum (Schltdl.) J.W. Grimes (syn. Psoralea australasica Schltdl.), a deep-rooted Australian native legume commonly known as tall verbine or native scurf-pea. Its natural distribution and the edaphic and climatic characteristics of germplasm collection sites within Australia are described. It also reports the results of three preliminary studies; two field studies on the establishment, persistence and herbage quality, and a glasshouse study to identify an effective Rhizobium strain for C. australasicum. In the field studies, C. australasicum established readily from seed and demonstrated similar persistence to Medicago sativa L. over a 3-year period in the medium rainfall wheat belt of southern New South Wales. The productivity of C. australasicum in year 3 was similar to M. sativa at one site but inferior at the second site. C. australasicum demonstrated superior persistence and higher herbage yields than Lotus corniculatus L. in year 3 at both sites. The mineral content of the leaves and stems of C. australasicum in these studies were similar to M. sativa and L. corniculatus for most elements except for Mo and Zn, which were significantly higher, and Na which was lower in C. australasicum. Organic matter digestibility of the leaves and stems of C. australasicum ranged from 79 to 89% and 62 to 72%, respectively, compared with 73–79% and 59–73% in M. sativa. Crude protein levels of C. australasicum leaves and stems were 22–28% and 15–27%, respectively, compared with 26–33% and 13–33% in M. sativa. The study of Rhizobium strains isolated from four South Australian soils identified a superior strain (SRDI 483) capable of establishing an effective symbiosis with C. australasicum. The potential of C. australasicum as a drought hardy perennial legume for extensive grazing systems where M. sativa fails to persist because of selective grazing is discussed. Its low palatability to sheep was seen as an advantage in assisting its survival in extensive low-input grazing systems.

Pasture and sheep responses to lime application in a grazing experiment in a high-rainfall area, south-eastern Australia. I. Pasture production

‘Managing Acid Soils Through Efficient Rotations (MASTER)’ is a long-term pasture–crop rotation experiment commenced in 1992. One of the objectives was to demonstrate the extent of crop, pasture, and animal responses to lime on a typical acidic soil in the 500–800 mm rainfall zone in south-eastern Australia. Two types of pastures (perennial v. annual pastures) with or without lime application were established in 1992. This paper presents the results of the pasture dry matter (DM) responses to lime application over 6 years from 1992 to 1997. Results showed that both perennial and annual pastures responded positively to lime on a highly acidic soil on the south-west slopes of New South Wales. Averaged across pasture types and 5 growing seasons, the limed pastures produced 18% more pasture DM (520 kg/ha, P < 0.05) than the unlimed pastures. Significant responses to lime were detected on perennial pastures (610 kg DM/ha, P < 0.05), but not on annual pastures, although the limed annual pastures produced more DM (420 kg/ha, P = 0.20) than the unlimed annual pastures. There was a large seasonal variation in pasture growth rate with the significant lime responses in winter and spring on both perennial pastures (P < 0.05) and annual pastures (P < 0.10 in winter and P < 0.05 in spring), but no responses in autumn and summer on either perennial or annual pastures. The extra growth in winter is of importance as winter is the period when feed is normally inadequate and limits stocking rates. It is recommended that perennial-based pastures should be promoted for the purposes of productivity, in terms of increasing pasture production and improving feed quality, and for the environmental benefits in terms of alleviating the soil acidity problem and reducing the risk of dryland salinity in the high-rainfall zone in south-eastern Australia.

Pasture and sheep responses to lime application in a grazing experiment in a high-rainfall area, south-eastern Australia. II. Liveweight gain and wool production

‘Managing Acid Soils Through Efficient Rotations (MASTER)’ is a long-term pasture–crop rotation experiment commenced in 1992. One of the objectives was to demonstrate the extent of crop, pasture, and animal responses to lime application on a typical acidic soil in the 500–800 mm rainfall zone of south-eastern Australia. Two types of pastures (perennial v. annual pastures) with or without lime application were established in 1992. Fifteen- to eighteen-month-old Merino hoggets were used as test animals and were changed annually. This paper reports the results of sheep responses to liming from the 4 continuous pasture treatments over 6 years from 1992 to 1997. The stocking rate was the same on all plots within a treatment during each rotation period, but was varied between treatments based on the pasture availability and sheep body condition. The most important findings from this study are that the limed treatments carried 29% and 27% more stock (up to 4 DSE/ha) than the unlimed treatments for perennial and annual pastures, respectively. As a result, the limed perennial pastures produced 27% more liveweight gain (62 kg/ha.year) and 28% more greasy wool (13 kg/ha.year) than unlimed perennial pastures, whereas the limed annual pastures produced 34% more liveweight gain (77 kg/ha.year) and 24% more greasy wool (11 kg/ha.year) than unlimed annual pastures. The significant responses to lime in liveweight and wool production were detected from the second growing season after the pastures were established. The increased sheep productivity on the limed treatment was due to a combination of increased pasture production and improved pasture quality. Perennial pastures showed a slight advantage in wool production, but not in liveweight gain. However, the seasonal variation of liveweight was greater on annual pastures than on perennial pastures. The larger variation in liveweight change could lead to more adverse effects on wool quality especially at high grazing pressures. Grazing management can be used to manipulate pasture and animal productivity to increase profits from lime use.

Chronic exposure to high glucose impairs bradykinin-stimulated nitric oxide production by interfering with the phospholipase-C-implicated signalling pathway in endothelial cells: evidence for the involvement of protein kinase C

AIMS/HYPOTHESIS

Overwhelming evidence indicates that endothelial cell dysfunction in diabetes is characterised by diminished endothelium-dependent relaxation, but the matter of the underlying molecular mechanism remains unclear. As nitric oxide (NO) production from the endothelium is the major player in endothelium-mediated vascular relaxation, we investigated the effects of high glucose on NO production, and the possible alterations of signalling pathways implicated in this scenario.

METHODS

NO production and intracellular Ca(2+) levels ([Ca(2+)](i)) were assessed using the fluorescent probes 4,5-diaminofluorescein diacetate and fura-2 respectively.

RESULTS

Exposure of cultured bovine aortic endothelial cells to high glucose for 5 or 10 days significantly reduced NO production induced by bradykinin (but not by Ca(2+) ionophore) in a time- and dose-dependent manner. This was probably due to an attenuation in bradykinin-induced elevations of [Ca(2+)](i) under these conditions, since a close correlation between [Ca(2+)](i) increases and NO generation was observed in intact bovine aortic endothelial cells. Both bradykinin-promoted intracellular Ca(2+) mobilisation and extracellular Ca(2+) entry were affected. Moreover, bradykinin-induced formation of Ins(1,4,5)P(3), a phospholipase C product leading to increases in [Ca(2+)](i), was also inhibited following high glucose culture. This abnormality was not attributable to a decrease in inositol phospholipids, but possibly to a reduction in the number of bradykinin receptors. The alterations in NO production, the increases in [Ca(2+)](i), and the bradykinin receptor number due to high glucose could be largely reversed by protein kinase C inhibitors and D: -alpha-tocopherol (antioxidant).

CONCLUSIONS/INTERPRETATION

Chronic exposure to high glucose reduces NO generation in endothelial cells, probably by impairing phospholipase-C-mediated Ca(2+) signalling due to excess protein kinase C activation. This defect in NO release may contribute to the diminished endothelium-dependent relaxation and thus to the development of cardiovascular diseases in diabetes.

p53-independent induction of p21(waf1/cip1) contributes to the activation of caspases in GTP-depletion-induced apoptosis of insulin-secreting cells

We investigated the role of some key regulators of cell cycle in the activation of caspases during apoptosis of insulin-secreting cells after sustained depletion of GTP by a specific inosine 5'-monophosphate dehydrogenase inhibitor, mycophenolic acid (MPA). p21(Waf1/Cip1) was significantly increased following MPA treatment, an event closely correlated with the time course of caspase activation under the same conditions. MPA-induced p21(Waf1/Cip1) was not mediated by p53, since p53 mass was gradually reduced over time of MPA treatment. The increment of p21(Waf1/Cip1) by MPA was further enhanced in the presence of a pan-caspase inhibitor, indicating that the increased p21(Waf1/Cip1) may occur prior to caspase activation. This notion of association of p21(Waf1/Cip1) accumulation with caspase activation and apoptosis was substantiated by using mimosine, a selective p21(Waf1/Cip1) inducer independent of p53. Mimosine, like MPA, also increased p21(Waf1/Cip1), promoted apoptosis and simultaneously increased the activity of caspases. Furthermore, knocking down of p21(Waf1/Cip1) transfection of siRNA duplex inhibited caspase activation and apoptosis due to GTP depletion. In contrast to p21(Waf1/Cip1), a reduction in p27(Kip1) occurred in MPA-treated cells. These results indicate that p21(Waf1/Cip1) may act as an upstream signal to block mitogenesis and activate caspases which in turn contribute to induction of apoptosis.

Phalaris persistence under rotational grazing on a highly acidic soil on the south-west slopes of New South Wales

Phalaris (Phalaris aquatica L.)-based pastures were established with and without lime in 1992 as a part of a long-term pasture–crop rotation experiment (Managing Acid Soils Through Efficient Rotations). Pre- and post-grazing pasture dry matter, phalaris basal cover and proportion of phalaris in sward were measured since 1992. In general, phalaris persisted well and its productivity was high on the highly acidic soil studied in the current experiment, and this was improved on the limed treatment. After establishment in 1992, the average proportion of phalaris in spring 2001 was 32.1% in the limed treatment and 15.6% in the unlimed treatment. Basal cover at the end of summer 2002 was 4.5% and 2.0% for the limed and unlimed treatments, respectively. The results from the current experiment showed that subsurface acidity (low pHCa and high exchangeable aluminium percentage in the 10–30 cm soil depth) had significant impacts on phalaris persistence. It is concluded that subsurface pH was one of the major constraints for the persistence of phalaris. The long-term management of soil acidity should aim to eliminate the exchangeable aluminium from the soil profile by maintaining a high pHCa (5.5 or above) in the 0–10 cm soil depth. Rainfall during growing season had no direct effect on phalaris persistence. Nevertheless, feed scarcity in dry years due to moisture stress often exacerbated grazing pressure on phalaris, which may affect the phalaris persistence indirectly. It is the grazing management in autumn and summer that had significant effects on phalaris persistence. It is suggested that rotational grazing plus strategic rest if possible in autumn could prolong the life of phalaris-based pastures. Repeated heavy grazing should be avoided during summer, particularly after light to moderate summer rainfall events have stimulated sprouting.

Effects of lime on the botanical composition of pasture over nine years in a field experiment on the south-western slopes of New South Wales

Two permanent pastures (annual pasture v. perennial pasture) were established in 1992 as part of the long-term field experiment, MASTER — Managing Acid Soils Through Efficient Rotations. The primary objective of the experiment was to develop an agricultural system that is economically viable and environmentally sustainable on the highly acidic soils in south-eastern Australia. This paper reports on the effects of lime on the botanical composition changes of annual and perennial pastures over 9 years. In general, lime increased the proportion of the desirable species, such as phalaris (Phalaris aquatica) in perennial pasture and subterranean clover (Trifolium subterraneum) in annual pastures, and decreased the proportion of the undesirable species, such as Vulpia spp., in both annual and perennial pastures, ultimately improving the quality of feed-on-offer to animals. As a result, the limed pastures carried 24% more sheep than the unlimed pastures, while maintaining individual animal performance similar for both limed and unlimed pastures. The phalaris-based perennial pasture was more stable in terms of maintaining the sown species than the annual pasture. Lime improved the persistence of phalaris and the longevity of the phalaris-based pasture should be at least 10 years. Lime changed the direction of plant succession of annual pastures. Without lime, Vulpia spp. gradually became more dominant while ryegrass and subterranean clover became less dominant in annual pastures. With lime, barley grass (Hordeum leporinum) gradually invaded the sward at the expense of ryegrass, thus reducing the benefits of lime, but this effect was less for the perennial pastures than for annual pastures. Liming perennial pastures should be more beneficial than liming annual pastures because of the beneficial effects on pasture composition. In addition, previously published work reported that liming perennial pastures improved sustainability through better use of water and nitrogen.

Prevalence of human papillomavirus in cervical cancer: a multicenter study in China

A large-scale epidemiologic survey on the prevalence of different types of human papillomavirus (HPV) in cervical cancer in China is indicated because of the implications for the development of diagnostic probes and vaccines against cervical cancer. A total of 809 cervical cancer specimens were collected from 5 regions in China including Shanghai, Guangzhou, Sichuan, Beijing and Hong Kong. HPV DNA was detected in 83.7% of the specimens. HPV-16 was present in 79.6%, HPV-18 in 7.5%, HPV-52 in 2.6% and HPV-58 in 3.8% of all HPV-positive specimens. The prevalences of HPV-16 and HPV-18 in Hong Kong were 61.7 and 14.8%, respectively, representing a lower HPV-16 and a higher HPV-18 proportion compared with the other regions. HPV-16 remained the most common HPV infection in both squamous cell carcinoma (SCC) and adenocarcinoma (AC). The proportion of HPV-18 infection was significantly higher in AC than in SCC.

Secretory Expression of Different C-terminal Truncated HCV E1 Proteins in Mammalian Cells and Characterization of the Expressed Products

Three fragments of the HCV envelope 1 (E1) with different C-terminal truncation at aa310, aa325, aa340 were cloned into the mammalian expression vector pSecTagB. An epitope in the hepatitis B surface antigen, preS1(21--47), were genetically engineered onto the N-terminus of the recombinant protein and used as an affinity tag for detection and purification. The resulting pSec-preS1-E1t310, pSec-preS1-E1t325 and pSec-preS1-E1t340 were transiently expressed in the HeLa cells and the antigenicity, secretory efficiency and glycosylation type of the recombinant E1 proteins were compared. All of the three recombinant proteins could be detected by both preS1 monoclonal antibody and E1 polyclonal antiserum. The expression products were secreted and highly mannose-type glycosylated, with S1E1t325 being secreted, indicating the influence of the hydrophobic regions on the secretion of the E1 protein. Three CHO cell lines expressing the proteins, S1E1t310, S1E1t325 and S1E1t340, were established and the CHO/pSecS1E1t325 was chosen for further study. The secreted S1E1t325 could be enriched from cell culture medium by the preS1 antibody-coupled Sepharose. The glycosylation analysis indicated the lack of complex glycogen even after the E1 was secreted via Golgi complexes. The established stable cell lines and anti-preS1 affinity method could be utilized to enrich and purify the HCV E1 expressed in mammalian cells, and may be used for further characterization of this protein.

Effect of Downstream Sequence on the Cleavage of Envelop Protein 1 Signal Sequence in Hepatitis C Virus

The RNA genome of hepatitis C virus encodes a polyprotein of 3 000 amino acids, which is processed into 10 viral proteins by proteases provided by host cells and virus itself. Multiple precursors are produced due to inefficient processing. Here, the study of E1 signal sequence (C/E1 site) processing in eukaryotic vaccinia virus/T7 system is reported. Differently truncated HCV structural proteins were expressed in this system. It was found that the efficient cleavage of E1 signal sequence was affected by downstream envelope protein sequences. When the lacZ gene encoding a product with similar size was engineered downstream to the E1 signal sequence, the inefficient cleavage of signal sequence was also observed, suggesting that the effect of downstream sequence on the cleavage was due to the presence of the envelop protein sequences. Computer-aided analysis clearly showed that E1 signal sequences was a typical signal sequence. The influence of downstream sequences to signal sequence cleavage demonstrated here was uncommon. To date, similar observations were only reported for the processing of IL-12 signal sequence and the C/prM site of flavivirus. As both flavivirus and HCV are classified into the same Flaviviridae family, this downstream-sequence-related cleavage of signal sequence worths further studying.

[Hemodynamics following + Gz stress in dog]

AIM

To investigate the character of hemodynamics following + Gz stress in dog.

METHODS

Nine anesthesia dogs were exposed to 5, 7 and 9 + Gz stress, 90 s at peak G. Each animal was instrumented to measure left ventricular pressure, thoracic aorta pressure, iliac arterial pressure,common carotid artery flow (CCAF) and ECG.

RESULTS

(1) Heart rate, CCAF and blood pressure at any place increased. They were greater than those before + Gz stress (P < 0.05). (2) There were much more arrhythmias following high + Gz stress. Most of arrhythmias were junctional premature beats, ventricular premature beats. 80% arrhythmias occurred within 3 min following + Gz stress. (3) Blood pressure appeared the highest in the second min following + Gz stress.

CONCLUSION

Great hemodynamic disturbance happened following high + Gz stress. There might were reperfusion arrhythmias. Protective measures should been noted following high + Gz stress.

Polarized absorption spectra of single-walled 4 A carbon nanotubes aligned in channels of an AlPO(4)-5 single crystal

We report the polarized optical absorption spectra of single-walled 4 A carbon nanotubes arrayed in the channels of an AlPO (4)-5 single crystal. When the light electric field (E) is polarized parallel to the tube direction (c), the spectra display a sharp peak at 1.37 eV, with two broadbands at 2.1 and 3.1 eV. In the E perpendicular c configuration, the tube is nearly transparent in the measured energy region 0.5-4.1 eV. The optical dipole selection rules are discussed, and the absorption bands are assigned to the dipole transitions between the Van Hove singularities. The measured absorption spectra agreed well with the ab initio calculations of band structure based on the local density function approximation.

Superconductivity in 4 angstrom single-walled carbon nanotubes

Investigation of the magnetic and transport properties of single-walled small-diameter carbon nanotubes embedded in a zeolite matrix revealed that at temperatures below 20 kelvin, 4 angstrom tubes exhibit superconducting behavior manifest as an anisotropic Meissner effect, with a superconducting gap and fluctuation supercurrent. The measured superconducting characteristics display smooth temperature variations owing to one-dimensional fluctuations, with a mean-field superconducting transition temperature of 15 kelvin. Statistical mechanic calculations based on the Ginzburg-Landau free-energy functional yield predictions that are in excellent agreement with the experiments.

Expression of HLA class I, beta(2)-microglobulin, TAP1 and IL-10 in Epstein-Barr virus-associated nasal NK/T-cell lymphoma: Implications for tumor immune escape mechanism

Several mechanisms of immune escape might be in operation in Epstein-Barr virus (EBV)-associated nasal NK/T-cell lymphoma. We have previously shown the downregulation of the immunogenic EBV nuclear antigens by alternative promoter usage and the preferential selection of the deletion genotype of latent membrane protein 1 in nasal lymphoma. To understand further the strategies used for immune escape by this tumor, we examined by immunohistochemistry HLA class I expression in 15 cases using frozen sections, along with beta(2)-microglobulin and transporter associated with antigen processing 1 (TAP1) expression in 39 cases using paraffin sections. All nasal NK/T-cell lymphomas showed positive staining for HLA class I, beta(2)-microglobulin and TAP1 on most tumor cells, except for two cases (5%) in which most of the tumor cells lacked beta(2)-microglobulin staining. We next immunostained for interleukin-10 on frozen sections in 13 cases, all of which showed strong expression by most tumor cells. Transcription of human interleukin-10 but not EBV BCRF1 (viral interleukin-10) was identified by reverse transcriptase-polymerase chain reaction in these nasal NK/T-cell lymphomas. Overall, our data suggest that global downregulation of HLA class I or TAP1 rarely accounts for the ability of nasal NK/T-cell lymphoma to evade immunosurveillance and that other immune escape mechanisms may be operating in nasal NK/T-cell lymphoma, such as production of interleukin-10 to suppress the local immune response.

Crop responses to lime in long-term pasture-crop rotations in a high rainfall area in south-eastern Australia

A long-term trial, known as ‘managing acid soils through efficient rotations’ (MASTER), commenced in 1992 to develop and demonstrate a cropping system that is economically viable on the highly acid soils of the traditional permanent pasture region in south-eastern Australia, so that their fertility is sustained or improved. There were 2 permanent pasture systems and 2 pasture–crop rotations, each with and without lime. This paper reports the effect of lime on crop production over the first cycle (6 years). On annual pasture–crop rotations, lime significantly increased the dry matter production at anthesis and grain yields of wheat (cv. Dollarbird) compared with the unlimed treatments. Averaged across years from 1992 to 1997 (excluding the severe drought year 1994), wheat crops produced 1.6 t/ha more grain on the limed treatments than on the unlimed treatments (3.6 v. 2.0 t/ha). On perennial pasture–crop rotations, the lime effects varied with crops grown at each phase and year. For example, despite being tolerant of acidity, oats (cv. Yarran) responded to lime in 1996. Likewise, triticale (cv. Abacus) responded to lime in 1997. Wheat (cv. Dollarbird) that is moderately tolerant to acidity responded to lime in phase 6 from 1992 to 1997 excluding 1994 (3.5 v. 1.7 t/ha). Acid-tolerant wheat varieties, triticale, and narrow-leaf lupins are considered the most viable crops for the soil and climatic conditions encountered in this high rainfall (5000—800 mm per annum) area of south-eastern Australia.

Can endothelial seeding enhance patency and inhibit neointimal hyperplasia? Experimental studies and clinical trial of endothelial seeded venous prostheses

BACKGROUND

Venous prostheses have poor long-term patency; to improve this situation, experimental studies have been carried out.

METHODS

Methods of endothelial cell harvesting, prosthetic seeding and implantation mainly in the inferior vena cava were studied in 127 dogs. Evaluations were conducted by angiography, gross appearance, light, scanning and transmission electron microscopic observations, histo-fluorescent staining, as well as radioimmunoassay.

RESULTS

It was found that at five to ten days following implantation, the prosthetic endothelialisation could be reliably achieved in the seeded group and a 100% patency of the seeded inferior vena caval prostheses was attained at 100 days. The thickness of the neointima in the seeded group at 10 and 100 days was 299 microm and 302 microm, respectively. The metabolite of PGI2 from extrinsic arachidonic acid, 6-keto PGF1a, produced by cells from seeded graft was significantly higher than that from spontaneously formed cells and the reverse found with thromboxane B2. A temporary (one week) distal (femoral) arteriovenous fistula enhanced graft patency. These results indicated that the early endothelialisation of grafts by seeding enhanced the patency and inhibited intimal hyperplasia of venous prostheses. The clinical outcome was impressively improved from our previous experience with ten of eleven venous grafts patent over a follow-up period of six to nine years. These might result from the realization of early endothelialisation and its cells derived from seeding being able to produce significantly more PGI2 and less thromboxane B2.

CONCLUSIONS

The endothelial cell seeding technique may bring us much closer to an ideal venous prosthesis.

Effects of glutamine isomers on human (Caco-2) intestinal epithelial proliferation, strain-responsiveness, and differentiation

Enteral feeding with small amounts to stimulate bowel motility, and glutamine supplementation, which provides nutrients selectively used by intestinal epithelial cells, might preserve the gut mucosa during fasting. We evaluated the effects of the interaction between mechanical strain and glutamine supplementation in human Caco-2 intestinal epithelial cells, and pursued the finding of equivalent effects of L- and D-glutamine in Caco-2, HT-29, and primary malignant human colonocytes. Caco-2 cells were subjected to repetitive strain in media containing 2 mmol/L of L-glutamine and media supplemented with L- or D-glutamine. Proliferation was determined by automated cell counting. Differentiation and cellular production of L-glutamine were determined spectroscopically. Rhythmic deformation stimulated Caco-2 proliferation in a frequency-dependent manner. Maximal stimulation occurred at 10 cpm, consistent with in vivo frequencies of peristalsis and villous motility. Deformation at 10 cpm and L-glutamine supplementation from 2 to 5 mmol/L concentrations independently stimulated Caco-2 proliferation; the combination further increased proliferation. D-Glutamine supplementation yielded similar results, although with lesser potency. Furthermore, both L- and D-glutamine equivalently reduced Caco-2 dipeptidyl dipeptidase activity. The effects of each isoform were blocked by 1 to 3 mmol/L acivicin, a selective antagonist of glutamine metabolism. Indeed Caco-2 and HT-29 cells and primary malignant colonocytes each metabolized D-glutamine to L-glutamine. Glutamine supplementation in fasting patients might prove synergistic with stimulation of bowel motility by non-nutritive feeding, whereas tissue-specific variations in D-glutamine metabolism might facilitate selective nutripharmaceutical targeting of the gut mucosa.

Molecular cloning of a gene encoding a 20S proteasome beta subunit from Plasmodium falciparum

A novel gene was cloned from Plasmodium falciparum. Database searches indicated this gene to be a member of the 20S proteasome beta-subunit family. Comparison of the gene's genomic DNA sequence with cDNA sequence revealed a 156-bp intron 85 bp downstream from the start codon. The nucleotide sequence of the gene contains one open reading frame encoding 265 amino acids with a predicted molecular mass of 30.9 kDa and a pI of 6.2. Northern blot analysis showed the transcript size to be approximately 1.6 kb indicating that some 800 bp of the transcript is non-coding.

Effects of inhibitors of guanine nucleotide synthesis on membrane potential and cytosolic free Ca2+ levels in insulin-secreting cells

Adenine nucleotides play an important role in the control of membrane potential by acting on ATP-sensitive K+ (K(ATP)) channels and, in turn, modulating the open probability of voltage-gated Ca2+ channels in pancreatic islet beta-cells. Here, we provide evidence that guanine nucleotides (GNs) also may be involved in the modulation of these events in vivo. GNs were depleted by treatment of HIT-T15 cells with mycophenolic acid (MPA). Resting membrane potential was more depolarized in cells treated for 3 and 6 hr with MPA than in control cells, and this effect was inhibited by diazoxide. After 6 hr of exposure to MPA, basal cytosolic free Ca2+ concentrations ([Ca2+]i) were elevated by 20%. Increments in [Ca2+]i induced by submaximal concentrations of K+ (10-15 mM) or bombesin were enhanced by > 50%. Opening K(ATP) channels with diazoxide lowered basal [Ca2+]i in MPA-treated cells to normal and abrogated the enhanced [Ca2+]i responses. However, an L-type Ca2+ channel blocker only abolished the enhanced [Ca2+]i response to stimuli and had no effect on the elevated basal [Ca2+]i, in contrast to EGTA, which obliterated both, implying that the latter was due to Ca2+ influx via non-L-type Ca2+ channels. These effects on ion fluxes were attributable specifically to GN depletion, since guanosine, which restores GTP content and the GTP/GDP ratio, but not adenosine, prevented all MPA-induced ion changes; furthermore, the latter were mimicked by mizoribine (a structurally dissimilar GTP synthesis inhibitor). It is concluded that, in addition to adenine nucleotides, GNs might contribute to the modulation of K(ATP) channels in intact beta-cells. In addition, GN depletion appeared to be able to reduce stimulated insulin secretion by a mechanism largely independent of the changes of ion fluxes observed above.

[Cardiovascular response to high sustained +Gz stress in dogs]

Objective. To investigate features of electrocardiography (ECG) and arterial pressure in dog during and after +Gz stress. Method. Six anesthetized dogs were catheterized for the measurement of ascending aortic pressure (AP) and common iliac arterial pressure (CIAP). A lead of ECG was monitored continuously. Then, dogs were placed supine in rotatable platform on one arm of an 1.7 m radius centrifuge. The animals were exposed serially to acceleration profiles of up to +7 Gz, consisting of a slow onset to peak acceleration, 90 s peak G, and a rapid decline back to control. A recovery time of at least 20 min was allowed after each acceleration profile. Result. (1) The amplitude of P-wave was influenced by the magnitude of the acceleration (2.3 +/- 0.2 mV at rest vs. 4.5 +/- 0.5 mV at +3 Gz, 4.8 +/- 0.3 mV at +5 Gz and 5.3 +/- 0.7 mV at +7 Gz, respectively P<0.05). (2) It appeared that arterial mean pressure increased and pulse pressure decreased in CIAP during high +Gz stress. (3) AP increased greatly after +Gz stress (17.29 +/- 5.59/11.31 +/- 3.86 kPa at rest vs. 27.53 +/- 6.12/20.62 +/- 1.86 kPa 30s after +7 Gz P<0.01). Conclusion. (1) The change of the amplitude of P-wave reflected the atrial displacement which may be the reason of arrhythmia. (2) The perfusion pressure is an important physiological parameter to the cardiovascular dysfunction during high +Gz stress. (3) Greatly higher AP after +Gz stress could be a feature of vascular exhaustion.

[p53 gene expression of human hepatoma cell lines and their sensitivities to parvovirus H-1]

DNA structure and expression of p53 gene in human hepatoma cell lines SMMC-7721, YY-8103 and a spontaneously transformed liver cell line L-02 were analysed using the following method: analysis of allelic losses on chromosome 17p, PCR/SSCP, Northern blot and immunoprecipitation. There was no point mutation found in the exons 4-9 of the p53 gene, and a low level of expression of p53 gene was detected in the three cell lines. These observations were in agreement to the reported results of the relevant experiment using the human hepatoma cell line QGY-7703. Sensitivities of these cell lines and other eight human hepatoma cell lines (QGY-7703, PLC/PRF/5, Tong/HCC, Huh-7, FOCUS, Hep3B, SK-Hep-1, HepG2) with known p53 backgrounds to parvovirus H-1 was assayed using MTT method. Abnormality in the structure and/or function was observed in all of the cell lines examined except HepG2. The cell line HepG2 with normal structure and function of the p53 gene was found to be the least sensitive to H-1 in comparison to all the cell lines which have defeated structure and/or function of the p53 gene. The present study serves as a preliminary evidence that enhancement of the sensitivity of human hepatoma cell lines to H-1 is correlated to the abnormality of the structure and/or function of the p53 gene.

Acoustic evaluation of Isshiki type III thyroplasty for treatment of mutational voice disorders

The goal of this study was to determine if there are acoustical differences between pre- and post-surgical voices and to evaluate the effectiveness of Isshiki type III thyroplasty in 11 male patients with mutational voice disorders. Acoustic measures were obtained both pre- and post-operatively. A comparison of pre- and post-operative fundamental frequency (Fo), voice frequencies, and vocal intensity obtained from a sustained vowel /i/ during different phonatory tasks was made. The results from the present study demonstrated that after operation the voice frequencies were significantly decreased (p < 0.05). The vocal intensity tended to reduce slightly as the voice frequency lowered. However, there were no statistically significant differences in the pre- and post-operative measures of vocal intensity (p > 0.5). The pre-operative high pitched voices of all the male patients were lowered up to the normal value by the type III thyroplasty.

Effect of plasmid DNA on immunogenicity of HBsAg-anti-HBs complex

Hepatitis B surface antigen (HBsAg) complexed with anti-HBs is more immunogenic than HBsAg alone in mice. This complex is usually used with alum as an adjuvant, which can enhance humoral response but inhibits cell-mediated immune responses. To improve the immunogenicity of HBsAg-anti-HBs, we immunized mice with a combination of this immunogenic complex and pCMVHBs, a plasmid encoding HBsAg, or the vector pCMV. Both plasmids enhanced the anti-HBs response induced by the immunogenic complex. We found 20 microg of plasmid or vector enhanced the anti-HBs response in all mice, whereas 1 microg was less effective. Splenocytes from different immunized groups were stimulated with HBsAg in vitro, and the highest level of IL-2 detected in the supernatant was found in mice immunized with HBsAg-anti-HBs plus pCMVHBs. A plasmid (pcDNA3c191) encoding core protein of hepatitis C virus (HCV) was used as an adjuvant to the immunogenic complex. A preliminary result showed that pcDNA3c191 not only enhanced the immunogenicity of HBsAg-anti-HBs, but also induced anti-HCV core antibodies. Immunization using a plasmid DNA encoding one viral antigen in combination with antigen and antibody complex of another microbial origin could be a new approach to the development of multivalent vaccines.

Strain induces Caco-2 intestinal epithelial proliferation and differentiation via PKC and tyrosine kinase signals

Although the intestinal epithelium undergoes complex deformations during normal function, nutrient absorption, fasting, lactation, and disease, the effects of deformation on intestinal mucosal biology are poorly understood. We previously demonstrated that 24 h of cyclic deformation at an average 10% deformation every 6 s stimulates proliferation and modulates brush-border enzyme activity in human intestinal Caco-2 cell monolayers. In the present study we sought potential mechanisms for these effects. Protein kinase C (PKC) activity increased within 1 min after initiation of cyclic deformation, and the PKC-alpha and -zeta isoforms translocated from the soluble to the particulate fraction. Cyclic deformation also rapidly increased tyrosine kinase activity. Tyrosine phosphorylation of several proteins was increased in the soluble fraction but decreased in the particulate fraction by cyclic deformation for 30 min. Inhibition of PKC and tyrosine kinase signals by calphostin C, G-06967, and erbstatin attenuated or blocked cyclic deformation-mediated modulation of Caco-2 DNA synthesis and differentiation. These results suggest that cyclic deformation may modulate intestinal epithelial proliferation and brush-border enzyme activity by regulating PKC and tyrosine kinase signals.

Morphological development of forage chicory under defoliation in the field and glasshouse

Four field and 2 glasshouse experiments were carried out to study the morphological development of forage chicory under defoliation from 1993 to 1996 at Massey University, Palmerston North, New Zealand. ‘Grasslands Puna’ chicory (Cichorium intybus L.) was used in all experiments except the last one, where 3 cultivars, ‘Grasslands Puna’, ‘PG90’, and ‘Orchies’, were compared. Puna chicory produced 2 separate growths from the crown, one in spring and the other in autumn, when left ungrazed. Defoliation stimulated the development of secondary shoots but suppressed the development of the primary shoot. Axillary shoots, however, developed fully regardless of whether plants were defoliated. The main source of feed from chicory for livestock was primary leaves during spring, and secondary and axillary leaves during summer and autumn. Orchies produced more primary leaves than Puna an PG90 because it had a larger crown, but there were no differences in the number of secondary shoots among cultivars. The development of axillary shoots varied with cultivars.

Amplitude-dependent modulation of brush border enzymes and proliferation by cyclic strain in human intestinal Caco-2 monolayers

Little is known about the effects of repetitive deformation during peristaltic distension and contraction or repetitive villus shortening on the proliferation and differentiation of the intestinal epithelium. We sought to characterize the effects of repetitive deformation of a physiologically relevant magnitude and frequency on the proliferation and differentiation of human intestinal epithelial Caco-2 cells, a common cell culture model for intestinal epithelial biology. Human intestinal epithelial Caco-2 cells were cultured on collagen-coated membranes deformed by -20 kPa vacuum at 10 cycles/minute, producing an average 10% strain on the adherent cells. Proliferation was assessed by cell counting and 3H-thymidine incorporation. Alkaline phosphatase and dipeptidyl dipeptidase specific activity were measured in cell lysates. Since cells at the membrane periphery experience higher strain than cells in the center, the topography of brush border enzyme histochemical and immunohistochemical staining was analyzed for strain-dependence. Cyclic strain stimulated proliferation compared to static cells. Proliferation was highest in the membrane periphery where strain was maximal. Strain also modulated differentiation independently of its mitogenic effects, selectively stimulating dipeptidyl dipeptidase while inhibiting alkaline phosphatase. Strain-associated enzyme changes were also maximal in areas of greatest strain. The PKC inhibitors staurosporine and calphostin C ablated strain mitogenic effects while intracellular PKC activity was increased by strain. The strain-associated brush border enzyme changes were attenuated but not blocked by PKC inhibition. Thus, strain of a physiologically relevant frequency and magnitude promotes proliferation and modulates the differentiation of a well-differentiated human intestinal epithelial cell line in an amplitude-dependent fashion. PKC may be involved in coupling strain to increased proliferation.

Amplitude-dependent modulation of brush border enzymes and proliferation by cyclic strain in human intestinal Caco-2 monolayers

Little is known about the effects of repetitive deformation during peristaltic distension and contraction or repetitive villus shortening on the proliferation and differentiation of the intestinal epithelium. We sought to characterize the effects of repetitive deformation of a physiologically relevant magnitude and frequency on the proliferation and differentiation of human intestinal epithelial Caco-2 cells, a common cell culture model for intestinal epithelial biology. Human intestinal epithelial Caco-2 cells were cultured on collagen-coated membranes deformed by -20 kPa vacuum at 10 cycles/minute, producing an average 10% strain on the adherent cells. Proliferation was assessed by cell counting and 3H-thymidine incorporation. Alkaline phosphatase and dipeptidyl dipeptidase specific activity were measured in cell lysates. Since cells at the membrane periphery experience higher strain than cells in the center, the topography of brush border enzyme histochemical and immunohistochemical staining was analyzed for strain-dependence. Cyclic strain stimulated proliferation compared to static cells. Proliferation was highest in the membrane periphery where strain was maximal. Strain also modulated differentiation independently of its mitogenic effects, selectively stimulating dipeptidyl dipeptidase while inhibiting alkaline phosphatase. Strain-associated enzyme changes were also maximal in areas of greatest strain. The PKC inhibitors staurosporine and calphostin C ablated strain mitogenic effects while intracellular PKC activity was increased by strain. The strain-associated brush border enzyme changes were attenuated but not blocked by PKC inhibition. Thus, strain of a physiologically relevant frequency and magnitude promotes proliferation and modulates the differentiation of a well-differentiated human intestinal epithelial cell line in an amplitude-dependent fashion. PKC may be involved in coupling strain to increased proliferation.

Amplitude-dependent modulation of brush border enzymes and proliferation by cyclic strain in human intestinal Caco-2 monolayers

Little is known about the effects of repetitive deformation during peristaltic distension and contraction or repetitive villus shortening on the proliferation and differentiation of the intestinal epithelium. We sought to characterize the effects of repetitive deformation of a physiologically relevant magnitude and frequency on the proliferation and differentiation of human intestinal epithelial Caco-2 cells, a common cell culture model for intestinal epithelial biology. Human intestinal epithelial Caco-2 cells were cultured on collagen-coated membranes deformed by -20 kPa vacuum at 10 cycles/minute, producing an average 10% strain on the adherent cells. Proliferation was assessed by cell counting and 3H-thymidine incorporation. Alkaline phosphatase and dipeptidyl dipeptidase specific activity were measured in cell lysates. Since cells at the membrane periphery experience higher strain than cells in the center, the topography of brush border enzyme histochemical and immunohistochemical staining was analyzed for strain-dependence. Cyclic strain stimulated proliferation compared to static cells. Proliferation was highest in the membrane periphery where strain was maximal. Strain also modulated differentiation independently of its mitogenic effects, selectively stimulating dipeptidyl dipeptidase while inhibiting alkaline phosphatase. Strain-associated enzyme changes were also maximal in areas of greatest strain. The PKC inhibitors staurosporine and calphostin C ablated strain mitogenic effects while intracellular PKC activity was increased by strain. The strain-associated brush border enzyme changes were attenuated but not blocked by PKC inhibition. Thus, strain of a physiologically relevant frequency and magnitude promotes proliferation and modulates the differentiation of a well-differentiated human intestinal epithelial cell line in an amplitude-dependent fashion. PKC may be involved in coupling strain to increased proliferation.

Electrochemical activity of 6-aminoquinolyl urea derivatives of amino acids and peptides. Application to high-performance liquid chromatography with electrochemical detection

6-Aminoquinolyl-N-hydroxysuccinimidyl carbamate (6-AQC) is a reagent used to increase the detection-sensitivity of amino acids and peptides in high-performance liquid chromatography with fluorescence detection. In this paper, the electrochemical characteristics of the derivatives of 6-AQC are described. Electrochemical detection of 6-AQC amino acids and peptide derivatives following reverse-phase HPLC are also reported. The response linearity of the derivatives on an amperometric detector was studied in the range of 5 pmol (0.5 mu M) to 2500 pmol (250 mu M). Approximately 2.5 pmol of the amino acid derivatives could be detected. The quantitative results of amino acids in plasma and a bovine serum albumin hydrolysate agreed well with values reported in the literature.

Detection of 54-kDa protein overexpressed by chloroquine-resistant Plasmodium berghei ANKA strain in pyronaridine-resistant P berghei ANKA strain

AIM

A 54-kDa protein overexpressed by chloroquine-resistant (CR) Plasmodium berghei ANKA strain was first reported by us. This study is conducted to detect the protein in pyronaridine-resistant (PR) P berghei ANKA strain.

METHODS

Immunoblotting analysis and immunoelectron microscopy were used.

RESULTS

PR parasites, like CR parasites, mainly overexpressed 2 major bands of 37 (36-38) kDa and 16 (15-17) kDa which were considered to be 2 subunits of 54 (52-62) kDa protein. Three of 7 times of experiments showed a 54-kDa and a 96 (95-100) kDa bands. The proteins were localized to be mainly scattered in cytoplasm of trophozoites, schizonts, and merozoites of erythrocytic stage of P berghei. Some of them were distributed in cytoplasm of erythrocytes infected with parasites.

CONCLUSION

Both PR and CR parasites overexpressed the same proteins.

A modified hepatitis B virus surface antigen with the receptor-binding site for hepatocytes at its C terminus: expression, antigenicity and immunogenicity

A modified hepatitis B virus (HBV) surface antigen, the SA-28 protein, was constructed and expressed by recombinant vaccinia virus in mammalian cells. This protein was composed of a PreS1 region-derived peptide (amino acids 21 to 47) that contained the hepatocyte receptor-binding site, joined to the C terminus of the major S protein at amino acid position 223. This modified surface antigen could be efficiently assembled into particles with a density of 1.23 g/ml and could be secreted from several mammalian cell lines. The results of immunoprecipitation revealed that the SA-28 protein was recognized by both the anti-S protein antibody and the anti-PreS1 antibody. A strong antibody response, against both the S protein and PreS1 epitopes, was induced in BALB/c mice immunized by the SA-28 particles indicating good immunogenicity. These results suggested that the HBV surface antigen consisting of the SA-28 protein could be a promising candidate as a new HBV vaccine with higher efficacy.

A new genetically engineered vaccine for animal growth promotion

The chemically synthesized somatostatin (ss) gene was fused in phase with the 3'-end of hepatitis B virus surface antigen (HBsAg) gene. The fusion gene HBs/ss was then recombined into the genome of vaccinia virus. This recombinant virus (vv-HBs/ss) can express hybrid HBsAg/ss particles which present as determinants on their surfaces, thereby bearing a good immunogenicity. This new strategical vaccine of ss can elicit the production of antibody capable of neutralizing ss in the plasma, and consequently enhance the growth of animals.

Physiochemical and immunological characterization of hepatitis A virus nucleocapsids expressed in a vaccinia virus/T7/EMCV system

Expression of the entire open reading frame of hepatitis A virus was achieved in a vaccinia virus/T7/EMCV hybrid system. The expressed antigens were characterized as particles with buoyant densities and sedimentation coefficients typical of empty capsids and pentamers of HAV. This was further confirmed by electron microscopy. All capsid proteins were determined as components of the particles which raised neutralizing antibodies in an immunized rabbit.

Polymeric 6-aminoquinoline, an activated carbamate reagent for derivatization of amines and amino acids by high-performance liquid chromatography

A new polymeric reagent containing the 6-aminoquinoline (6-AQ) tag was developed and applied for the off-line derivatization of amines and amino acids in high-performance liquid chromatography (HPLC). The synthesis and characterization of this polymeric reagent are described. An authentic external standard of a typical amine was synthesized and characterized for the determination of the derivatization efficiency. All amines had a derivatization efficiency higher than 50%; the derivatization of amino acids was performed under optimized phase-transfer catalysis reaction conditions. Derivatized amines and amino acids were separated under conventional reversed-phase conditions and determined by UV and FL detectors. To investigate the practical applications, this polymeric reagent was also used to derivatize protein hydrolysates.

Polydioxanone absorbable sutures in vascular anastomoses: experimental and preliminary clinical studies

To assess the safety and efficacy of polydioxanone suture (PDS) for vascular anastomoses, bilateral carotid end-to-end anastomoses using PDSs on the left and Dacron sutures on the right in 18 dogs were performed. The anastomoses were assessed at 4, 6 and 8 weeks after surgery. A breaking-strength test (300 mmHg) did not show a significant difference between PDS and Dacron anastomoses, but partial absorption was grossly evident in the PDS group. Some 35 venous and 21 arterial reconstructive procedures were also carried out using PDS in 53 patients. At follow-up of 3-5 (mean 3.5) years, none of the patients had experienced any suture-related complications. The results indicate that PDS maintains an adequate tensile strength in anastomoses until suture-line healing occurs, suggesting that this material may be safely used in venous or small arterial anastomoses. In addition, because it is absorbable, resulting in decreased foreign-body reactions, PDS may have the potential to improve the long-term patency of venous or small arterial reconstructions.