Liver T1ρ MRI measurement in healthy human subjects at 3 T: a preliminary study with a two-dimensional fast-field echo sequence

OBJECTIVES

The aim of this study was to explore the technical feasibility of T(1)ρ MRI for the liver, and to determine the normal range of liver T(1)ρ in healthy subjects at clinical 3 T.

METHODS

There were 15 healthy volunteers. Three representative axial slices were selected to cut through the upper, middle and lower liver. A rotary echo spin-lock pulse was implemented in a two-dimensional fast-field echo sequence. Spin-lock frequency was 500 Hz, and the spin-lock times of 1, 10, 20, 30, 40 and 50 ms were used for T(1)ρ mapping. The images were acquired slice by slice during breath-holding. Regions of interest (ROIs; n=5) were manually placed on each slice of the liver parenchyma region, excluding artefacts and vessels. The mean value of these ROIs (n=15) was regarded as the liver T(1)ρ value for the subject. Six subjects were scanned once at fasting status; six subjects were scanned once 2 h post meal; three subjects were scanned twice at fasting status; and seven subjects were scanned twice 2 h post meal.

RESULTS

When two readers measured the same 10 data sets, the interreader reproducibility (ICC: intraclass correlation coefficient) was 0.955. With the 10 subjects scanned twice, the ICC for scan-rescan reproducibility was 0.764. There was no significant difference for the liver T(1)ρ value at the fasting status (43.08±1.41 ms) and post-meal status (42.97±2.38 ms, p=0.867). Pooling together all the 32 scans in this study, the normal liver T(1)ρ value ranged from 38.6 to 48.3 ms (mean 43.0 ms, median 42.6 ms).

CONCLUSION

It is feasible to obtain consistent liver T(1)ρ measurement for human subjects at 3 T.

αA- and αB-crystallins interact with caspase-3 and Bax to guard mouse lens development

The small heat shock protein, α-crystallin, exists in two isoforms, αA and αB, and displays strong ability against stress-induced apoptosis. Regarding their functional mechanisms, we and others have demonstrated that they are able to regulate members in both caspase and Bcl-2 families. In addition, we have also shown that αA and αB may display differential anti-apoptotic mechanisms under certain stress conditions. While αA-crystallin regulates activation of the AKT signaling pathway, αB negatively regulates the MAPK pathway to suppress apoptosis induced by UV and oxidative stress. Although previous studies revealed that αA and αB could regulate members in both caspase and Bcl-2 families, the molecular mechanism, especially the in vivo regulation still waits to be elucidated. In the present communication, we present both in vitro and in vivo evidence to further demonstrate the regulation of caspase-3 and Bax by αA and αB. First, Surface Plasmon Resonance (SPR) and yeast two-hybrid selection analysis demonstrate that αA and αB directly bind to caspase-3 and Bax with differential affinities. Second, immunohistochemistry reveals that αA and αB regulate caspase-3 and Bax at different developmental stages of mouse embryo. Third, coimmunoprecipitation shows that αA and αB form in vivo interacting complexes with caspase-3 and Bax. Together, our results further confirm that αA and αB regulate caspase-3 and Bax in vitro and in vivo to regulate lens differentiation.

Vertebral body corner oedema vs gadolinium enhancement as biomarkers of active spinal inflammation in ankylosing spondylitis

OBJECTIVE

To investigate the relative performance of T(2) weighted short tau inversion-recovery (STIR) and fat-suppressed T(1) weighted gadolinium contrast-enhanced sequences in depicting active inflammatory lesions in ankylosing spondylitis (AS).

METHODS

Whole-spine MRI was performed on 32 patients with AS, who participated in a clinical trial of infliximab treatment, by STIR and contrast-enhanced sequences at baseline and after 30 weeks. The AS spine MRI-activity (ASspiMRI-a) scoring method was used. The images from these two imaging techniques were evaluated separately by two independent readers.

RESULTS

For the pre-treatment lesion status, the intraclass correlation coefficients comparing STIR readings and contrast-enhanced readings were 0.69±0.23 for Reader 1 and 0.65±0.21 for Reader 2. At baseline, the mean ASspiMRI-a score was 15.4% and 17.7% higher for contrast-enhanced images than for STIR images for Reader 1 and Reader 2, respectively. After infliximab treatment, Reader 1 rated an ASspiMRI-a score reduction of 50.8±33.6% and 25.3±35.3% for STIR images and contrast-enhanced images, respectively, whereas Reader 2 rated an ASspiMRI-a score reduction of 42.4±50.4% and 32.9±35.6% for STIR images and contrast-enhanced images, respectively.

CONCLUSION

While both contrast-enhanced and STIR sequences showed sensitivity to change over a short period of time after infliximab treatment, these two sequences may reflect different disease mechanisms.

First Report of Cylindrocladium Black Rot of Peanut Caused by Cylindrocladium parasiticum (Teleomorph Calonectria ilicicola) in Jiangxi Province, China

In July 2010, a serious disease of peanut (Arachis hypogaea) resembling Cylindrocladium black rot (CBR) was found in Longnan County, Jiangxi Province, China. Symptoms included chlorotic, yellowish and blighted leaves, and wilting of the plants. Taproots and hypocotyls were blackened and rotted. Clusters of reddish orange spherical fruiting bodies appeared in the lesions present on basal stems, pegs, pods, and roots of peanut. Disease incidence reached as much as 50% in some patches of the field. Plants with symptoms were sampled from fields. Microscopic examination revealed that the reddish orange, spherical fruiting bodies were the perithecia and measured 461.6 (337.5 to 609.4) × 395.5 (309.4 to 496.9) μm. With gentle pressure, asci and ascospores were exuded from perithecia. The asci were hyaline, thin walled, and long stalked. Ascospores were hyaline, falcate with one septum, and measured 43.5 (27.3 to 54.5) × 5.6 (4.1 to 6.8) μm with a length/width (L/W) ratio of 7.8 ± 1.3. A fungus with white-to-pale buff border mycelia and yellowish brown pigment was consistently isolated from the edge of basal stem lesions on potato dextrose agar at 25°C. Mycelia grew at temperatures ranging from 8 to 32°C and the optimum was 25 to 26°C. To determine the species, single-conidial isolates of the fungus were cultured on carnation leaf agar for 7 days at 25°C and 12 h of light/dark conditions. Conidia were hyaline, cylindrical with one to three septa (mostly three septa), and measured 49.3 (27.3 to 70.9) × 5.9 (4.1 to 6.8) μm with L/W ratio of 8.4 ± 1.6. Vesicles were globose and measured 5.5 to 10.9 μm in diameter. The fungus was identified as Cylindrocladium parasiticum (teleomorph Calonectria ilicicola) (1,2). A PCR assay was conducted on one representative isolate (JXLN32) by analyzing multilocus sequences of the TUB2 (coding β-tubulin protein), ACT (coding actin), and CaM gene (coding calmodulin protein) and were amplified and sequenced using the primers reported by Crous et al. (3). Sequences of the studied DNA regions were submitted to GenBank (Accession Nos. TUB2: JF429649; ACT: JQ070809; and CaM: JQ070808). BLAST searches with the existing sequences in GenBank showed that there was 99 to 100% identity with the existing sequences of C. ilicicola (GenBank Accession Nos. TUB2: AY725643; ACT: GQ280446; and CaM: GQ267402). To complete Koch's postulates, inoculum was prepared by mixing the microsclerotia (MS) suspension of the isolate (JXLN32) with soil at a proportion of 10 MS per g of soil. Ten replicate plastic pots containing five peanut seeds (cv. Yueyou 7) each were planted and placed in a glasshouse at 25 ± 2°C. The same number of peanut seeds was used as an uninoculated control. Typical basal stem and roots rot symptoms of CBR were observed in 2 months and C. parasiticum was reisolated from these inoculated diseased plants. No symptoms were detected on the control plants. To our knowledge, this is the first finding of Cylindrocladium black rot in Jiangxi Province, which is the main peanut-producing area in China. The disease has been previously reported in Guangdong Province in southern China but is not known elsewhere (4). Because of its ability to spread through seed and soil and its destructive potential, this pathogen may pose a serious threat to peanut production in China. References: (1) D. K. Bell and E. K. Sobers. Phytopathology 56:1361, 1966. (2) P. W. Crous et al. Mycol. Res. 97:889, 1993. (3) P. W. Crous et al. Stud. Mycol. 50:415, 2004. (4) R. Pan et al. Plant Pathol. 58:1176, 2009.

Insulin-like growth factor-1 boosts the developing process of condylar hyperplasia by stimulating chondrocytes proliferation

OBJECTIVE

The etiology of Condylar hyperplasia (CH) of human temporomandibular joint (TMJ) remains largely unknown. Our previous study has demonstrated that enriched insulin-like growth factor-1(IGF-1) was expressed in the proliferation and hypertrophic layers of CH cartilage. Accordingly, this study was aimed to investigate whether IGF-1 regulates CH chondrocytes proliferation in condylar cartilage overgrowth and explore the molecular mechanism of IGF-1 involved in.

METHODS

Chondrocytes were isolated from 6 CH and 3 normal cartilage (NC) specimens and cultured in alginate beads or monolayer, treated with IGF-1 or specific inhibitors such as 7-[trans-3-[(azetidin-1-yl)methyl]cyclobutyl]-5-(3-benzyloxyphenyl)-7H-pyrrolo[2,3-d]pyrimidin-4-amine (NVP-AEW541), U0126, and LY294002. Thereafter, cellular proliferation capacity was evaluated by Cell Viability Analyzer (alginate beads culture) or 3-(4,5-dimethylthiazo(-2-yl)-2,5-diphenyltetrazolium bromide (MTT) (monolayer culture). Gene expression levels of IGF-1, IGF-1 receptor (IGF-1R), collagen type II, type X and those genes associated with proliferation were evaluated by realtime PCR. Protein levels of IGF-1 and IGF-1R synthesized by CH chondrocytes were accessed by enzyme-linked immunosorbent assay (ELISA) and western blotting.

RESULTS

CH chondrocytes enhanced cellular proliferation capacity and expressed significantly higher levels of messenger RNA (mRNA) and protein expressions of IGF-1 and IGF-1R, as compared with NC chondrocytes. Furthermore, enriched IGF-1 enhanced CH chondrocytes proliferation, up-regulated the expressions of specific genes associated with cellular proliferation and elevated the gene expression of collagen type II A1 (COL2A1). Besides, IGF-1-mediated CH chondrocytes proliferation mainly depended on the mitogen-activated protein kinase (MAPK)-ERK pathway.

CONCLUSIONS

IGF-1 promotes human TMJ cartilage overgrowth in the developing process of CH by enhancing chondrocytes proliferation via MAPK-ERK pathway.

First Report of Peanut Cylindrocladium Black Rot Caused by Cylindrocladium parasiticum in Fujian Province, Eastern China

During late July and early August of 2010, a serious disease of peanut (Arachis hypogaea L.) resembling Cylindrocladium black rot (CBR) was found in Longyan City, Fujian Province of Eastern China. Aboveground symptoms were chlorosis and yellowing of leaves, a black rot of the basal stem and pegs, and wilting of the vines. Underground plant parts (including pods, pegs, taproots, and hypocotyls) were blackened and rotted. Orange-to-reddish spherical fruiting bodies appeared on the lesions of the basal stems and pegs of peanut. Disease incidence was approximately 20%. A fungus was consistently isolated from the edge of lesions on potato dextrose agar (PDA) amended with streptomycin and incubated at 25°C. The fungus produced white-to-pale buff mycelia with a yellowish brown pigment. Optimum growth of the fungus on PDA was at 25 to 30°C. Conidiophores were borne laterally on a stipe that terminated in a hyaline, globose vesicle measuring 5.5 × 10.9 μm in diameter. Conidia were hyaline, cylindrical, rounded at both ends, slightly wider at the base than at the apex, with one to three septa (mostly one septa), and measured 27.3 to 70.9 × 4.1 to 8.2 μm. Orange-to-reddish perithecia were readily formed in old cultures. The perithecia were subglobose to oval or obovate and measured 215.6 to 609.4 × 309.4 to 496.9 μm. The asci were hyaline, clavate, thin walled, long stalked, with each containing eight ascospores. Ascospores were hyaline, falcate, had one septum, and measured 27.3 to 54.5 × 4.1 to 6.8 μm. The fungus was identified as Cylindrocladium parasiticum Crous, M.J. Wingfield, & Alfenas (teleomorph Calonectria ilicicola) (1,2). The beta-tubulin gene fragment was amplified using the T1/Bt2b primers (3) and sequenced. The sequences of three isolates (GenBank Accession Nos. JF343965, JF429656, and JF429657), when compared with existing sequences in GenBank, had 95 to 99% sequence identity with Calonectria ilicicola (GenBank Accession Nos. AY725643 and AY725639). Pathogenicity tests were conducted by first culturing the fungus on wheat kernels for 2 weeks. Inoculated kernels were then used as inoculum and mixed with sterilized soil in a proportion of 1:20 by weight in plastic pots (10 × 9 cm). Noninoculated wheat kernels were mixed with sterilized soil in the same proportion and served as the control. Two-week-old peanut seedlings (cv. Yueyou No. 7) were transplanted into inoculated or noninoculated pots. There were five plants per pot and each treatment was replicated four times. The plants were incubated in a greenhouse at 25 ± 2°C. All of the treated plants exhibited typical basal stem and root rot symptoms of CBR 2 weeks after inoculation, while all of the control plants remained healthy. C. parasiticum was reisolated from the diseased plants. To our knowledge, this is the first report of CBR on peanut in Fujian Province in Eastern China. The disease has been previously reported in Guangdong Province in Southern China but is not known elsewhere (4). This pathogen may pose a serious threat to peanut production in China, where peanut is an important crop. References: (1) D. K. Bell and E. K. Sobers. Phytopathology 56:1361, 1966. (2) P. W. Crous et al. Mycol. Res. 97:889, 1993. (3) P. W. Crous et al. Can. J. Bot. 77:1813, 1999. (4) R. Pan et al. Plant Pathol. 58:1176, 2009.

First Report of Nectria haematococca Causing Stem Rot of Soybean in China

In October 2010, soybean (Glycine max) plants growing in commercial soybean fields in Zengcheng City, Guangdong Province developed symptoms consisting of stem and root rot, yellowing, and defoliation of leaves. Reddish, spherical fruiting bodies appeared in lesions that developed on stems. Plants with symptoms were sampled from fields. Fruiting bodies were excised from diseased tissues. Microscopic examination revealed that they were perithecia, globose to pyriform, and measured 197 to 260 μm in diameter and 226 to 358 μm long. When squeezed gently, cylindrical to clavate asci, 7.2 to 9.6 μm in diameter and 75.4 to 92.0 μm long, containing eight ascospores were exuded from the perithecia. Ascospores were ellipsoid to obovate, two celled, slightly constricted at the septum, had longitudinal striations, and measured 4.9 to 6.0 μm in diameter and 10.6 to 15.0 μm long. The fungus was isolated from the basal stem tissues of diseased soybean plants and cultured on potato dextrose agar (PDA) medium amended with streptomycin sulfate. On PDA, the culture developed into blue-pigmented colonies with whitish mycelium that produced oval to cylindrical microconidia. Microconidia had 0 to 1 septum, ranged from 2.5 to 5.2 × 7.6 to 29.4 μm, and were produced on monophialides. Macroconidia were cylindrical to falcate, thick walled, 2 to 5 septa, and 3.5 to 6.0 × 25.4 to 66.8 μm. Chlamydospores were present and ranged from 6.8 to 13.6 × 5.5 to 9.5 μm. Orange-to-reddish perithecia were readily formed in old culture. These morphological characteristics were consistent with descriptions of Nectria haematococca (anamorph Fusarium solani) (1). The rDNA internal transcribed spacer (ITS) region and the fragment of translation elongation factor 1-alpha (EF1-α) genes of the fungus were amplified, respectively, with universal primers ITS1/ITS4 and ef1/ef2 primers and sequenced. BLAST searches showed that the ITS sequences of three isolates (GenBank Accession Nos. JN015069, JN190942, and JN190943) had 99% similarity with those of N. haematococca(GenBank Accession Nos. DQ535186, DQ535185, and DQ535183) and the EF1-α sequences of three isolates (GenBank Accession Nos. JN874641, JN874642, and JN874643) had 100% similarity with those of F. solani (GenBank Accession Nos. DQ247265 and DQ247327). Completion of Koch's postulates confirmed the pathogenicity of the isolates in a replicated experiment. Thirty-day-old soybean seedlings of cultivar Huaxia No. 3 were inoculated by soaking their root systems in a conidial suspension (10⁶ conidia per ml) for 30 min and then transplanted in plastic pots (20 cm in diameter) and incubated at 25 ± 2°C in a greenhouse. Control plants were treated with sterile water in the same way. There were four plants per pot and there were six replicates for each treatment. Within 3 weeks, more than 70% of the inoculated plants exhibited symptoms of leaf yellowing, stem rot, and root rots while control plants were symptomless. N. haematococca was reisolated from the diseased plants. To our knowledge, this is the first report of N. haematococca causing stem rot of soybean in China and the first description of sexual reproduction of F. solani causing soybean stem rot in nature. This pathogen may pose a serious threat to soybean production in China where soybean is a main crop. Reference: (1) C. Booth. The Genus Fusarium. CAB International, Wallingford, UK, 1971.

Compromised perfusion in femoral head in normal rats: distinctive perfusion MRI evidence of contrast washout delay

OBJECTIVES

The femoral head is prone to osteonecrosis. This study investigated dynamic contrast-enhanced (DCE) MRI contrast washout features of the femoral head and compared the data with data from other bony compartments in normal rats.

METHODS

7-month-old Wistar rats were used. DCE MRI of the right hip (n=18), right knee (n=12) and lumbar spine (n=10) was performed after an intravenous bolus injection of Gd-DOTA (0.3 mmol kg(-1)). Temporal resolution was 0.6 s for hip and spine, and 0.3 s for knee. The total scan duration was 8 min for hip and spine, and 4.5 min for knee. The regions of interest for enhancement measurement included femoral head, proximal femoral diaphysis, distal femoral diaphysis and epiphysis, proximal tibial epiphysis and diaphysis, and lumbar vertebrae L1-5.

RESULTS

Femoral head showed no enhancement signal decay during the DCE MRI period, while all other bony compartments showed a contrast washin phase followed by a contrast washout phase. In the knee joint, the contrast washout of the proximal tibia diaphysis was slower that of other bony compartments of the knee.

CONCLUSION

Based on the evidence of delayed contrast washout, this study showed that blood perfusion in the femoral head could be compromised in normal rats.

Hepatic arterial perfusion is essential for the spontaneous recovery from focal hepatic venous outflow obstruction in rats

We previously observed that focal hepatic venous outflow obstruction recovered spontaneously by the formation of sinusoidal canals in a rat model of portal hyperperfusion. We aimed to investigate whether the lack of hepatic arterial perfusion aggravates parenchymal damage, decelerates recovery and influences the formation of sinusoidal canals after focal hepatic venous outflow obstruction. Rats were subjected to arterialized versus nonarterialized syngeneic liver transplantation after ligating the right median hepatic vein in the donor. Hepatic damage, microcirculation, regeneration and vascular remodeling were evaluated. In arterialized-recipients, confluent necrosis interspersed with viable periportal islands of hepatocytes, and vascularized sinusoidal canals with visible blood flow, surrounded by normal sinusoidal structure, were visible on postoperative day (POD) 2. Complete parenchymal recovery was consequently established by resorption of necrosis and hepatocyte proliferation, detected in viable portal islands and border zone. Lack of hepatic arterial perfusion caused complete necrosis in the obstruction zone without viable hepatocytes in the periportal area on POD2. Hepatocyte proliferation was only visible in the border zone. On POD28, perfused vascular structures, without neighboring normal sinusoidal structures, were observed in the scar-like area. Hepatic arterial perfusion determined the extent of hepatic necrosis, the formation of vascularized sinusoidal canals and the parenchymal recovery, after focal hepatic venous outflow obstruction.

First Report of Peanut Foot Rot Caused by Neocosmospora vasinfecta var. africana in Jiangxi Province, China

From June 2009 to November 2010, a disease was observed on peanut (Arachis hypogaea L.) in Ganzhou City, Jiangxi Province, China. Infected plants initially exhibited yellow leaves, then defoliated, and finally wilted and died. Basal stems, pegs, pods, and roots became black and rotted, with many orange-brown spherical fruiting bodies emerging on the lesions. Disease incidence reached as high as 30% in some plots, especially in those covered with plastic sheets after planting to control weeds. Isolations from 68 diseased plants were conducted on potato dextrose agar (PDA) amended with streptomycin sulfate and incubated at 25°C. A fungus was consistently isolated from the edge of the lesions. Mycelia grew at a linear rate of 3.9 mm per day on PDA at 25°C forming a pale buff, floccose colony with abundant orange-red perithecia. Perithecia were globose to pyriform, ostiolate and with a short neck, and measured 151 to 353 × 141 to 313 μm. Asci were narrowly cylindrical to clavate, thin walled with a short stalk, measured 100 to 160 μm high and 9 to 15 μm in diameter, and were eight spored. Ascospores were uniseriately arranged, globose to ellipsoid, nonseptate, thick walled, hyaline to pale yellow, and measured 7 to 16 × 7 to 12 μm. Scanning electron microscopy revealed that the wall of the ascospores had cerebriform ornamentation. Conidia were cylindrical to oblong-ellipsoidal, hyaline, most one celled, and measured 3 to 15 × 1 to 5 μm, aggregating in a gelatinous mass on the tip of the conidiogenous cell, which usually arose directly from the vegetative mycelium. The fungus was identified as Neocosmospora vasinfecta var. africana (anamorph Acremonium sp.) (1). The rDNA internal transcribed spacer (ITS) region of the fungus was amplified with universal primers ITS1/ITS4 and sequenced. The sequences of a representative isolate (No. N-JXLN02) were submitted to GenBank (Accession No. JF708085) and BLAST searches showed 99 to 100% similarity with sequences of N. vasinfecta deposited in GenBank (Accession Nos. HM461900, HM461901, and AY381142 ). Pathogenicity tests were conducted on 36 2-week-old peanut seedlings, cv. Yueyou No. 13, in plastic pots. Plants were inoculated by drenching the soil near the shoot with a mixed suspension of conidia and ascospores (10⁵ spores per ml). Control plants were treated with sterile water. All plants were then incubated in a moist chamber at 25 ± 2°C. Fifteen days after inoculation, all inoculated plants showed lesions on basal stems and black root rot similar to that observed on naturally infected plants. No disease was observed on control plants. The pathogen was reisolated from infected tissues. To our knowledge, this is the first finding of Neocosmospora foot rot of peanut in Jiangxi Province, where outbreaks of this disease have been observed in several counties. The pathogen will pose a threat to peanut, which is a major oil crop in China. It has been previously reported in Taiwan (2) and recently in Guangdong Province, though the subspecies of the pathogen was not identified in the latter case (3). References: (1) P. F. Cannon and D. L. Hawksworth. Trans. Br. Mycol. Soc. 82:673, 1984. (2) J. W. Huang et al. Plant Pathol. Bull. 1:203, 1992. (3) R. Pan et al. Plant Pathol. 59:1172, 2010.

First Report of Soybean Neocosmospora Stem Rot Caused by Neocosmospora vasinfecta var. vasinfecta in China

During October 2009, the occurrence of a disease on soybean (Glycine max) was observed in several fields in Boluo County and Zengcheng City, Guangdong Province. Top leaves of infected plants initially turned yellow and plants eventually were defoliated, while stems and roots became black and rotted. The stem lesions sometimes extended 10 to 15 cm upward from the soil surface. Orange-to-brown spherical fruiting bodies, which were very similar with those of the soybean red crown rot pathogen, scattered or congregated on the stem lesions. Plants with symptoms were sampled from fields. Fruiting bodies were excised from diseased tissues. Microscopic examination revealed that they were perithecia, globose to pyriform, ostiolate with a short neck, and measured 160 to 298 × 151 to 235 μm. Under gentle pressure, asci and ascospores were exuded from these perithecia. Asci were eight spored, narrowly cylindrical to clavate, thin walled, with a short stalk, and measured 58 to 124 μm long and 8 to 15 μm in diameter. Ascospores were uniseriately arranged, globose to ellipsoid, thick walled, one celled, hyaline to pale, and measured 14 to 17 × 8 to 12 μm. Isolation was made from stem tissues at the edge of disease lesions on potato dextrose agar (PDA) amended with streptomycin sulfate and incubated at 25°C. Mycelia were white and floccose. Conidia were cylindrical to oblong-ellipsoidal, hyaline, one celled, and measured 6 to 22 × 2 to 5 μm, aggregating in a slimy mass on the apex of the conidiogenous cell. Abundant orange-to-brown spherical perithecia were produced on the colony. Ascospores had walls with a rugose ornamentation that could be clearly seen under a scanning electron microscope. The fungus was identified as Neocosmospora vasinfecta var. vasinfecta (anamorph Acremonium sp.) (1). The internal transcribed spacer (ITS) region of rDNA of two isolates were amplified with universal primers ITS1/ITS4 and sequenced (GenBank Accession No. JF705861 and JF705862), and comparisons with GenBank accessions showed 99% similarity with N. vasinfecta strain Pec070 (Accession No. FJ940902) and strain NRRL22497 (Accession No. AY381142). Pathogenicity tests were conducted. Five, 3-week-old seedlings of soybean cv. Huaxia No. 3 planted in plastic pots (20 cm in diameter) were wounded with a needle at the base of the stem below the soil line and near the root system, and then inoculated by drenching the soil with a conidial suspension (10⁵ per ml). Control plants were inoculated with sterile water. There were six replicates for each treatment. The treated plants were incubated at 25 ± 2°C in a greenhouse. All inoculated plants exhibited symptoms of leaf yellowing and black rot of stems and roots 3 weeks after inoculation. N. vasinfecta var. vasinfecta was reisolated from the diseased plants. All control plants remained healthy. To our knowledge, this is the first observation of Neocosmospora stem rot of soybean in China. The pathogen could pose a threat to soybean, which is a major crop in China. This disease has been previously reported in the United States though the anamorph of the pathogen has either not been identified or has been identified as a Cylindrocarpon sp. (2,4). This fungus is also associated with human infections (3). References: (1) P. F. Cannon and D. L. Hawksworth. Trans. Br. Mycol. Soc. 82:673, 1984. (2) F. A. Gray et al. Plant Dis. 64:321, 1980. (3) P. Manikandan et al. Med. Mycol. 46:279, 2008. (4) D. V. Phillips. Phytopathology 62:612, 1972.

A novel end-to-side anastomosis technique for hepatic rearterialization in rat orthotopic liver transplantation to accommodate size mismatches between vessels

BACKGROUND/AIMS

We present our modification of a sutured arterial anastomosis in orthotopic rat liver transplantation as well as a literature survey and analysis of the existing techniques of rearterialization with regard to technical difficulties and potential limitations.

METHODS

The donor common hepatic artery (CHA) was anastomosed to the enlarged lumen of the recipient proper hepatic artery (PHA), tailored to match the size of the donor CHA, with an end-to-side interrupted suture technique. Vascular patency of hepatic rearterialization was assessed both intraoperatively and at the time the liver grafts were harvested (postoperative days 2 and 28). The effect of arterialization on hepatic morphology was confirmed by histological examination and compared to nonarterialized rat orthotopic liver transplantation.

RESULTS

The CHAs had a significantly larger diameter (up to 3-fold) compared to the PHAs, which represents a considerable size mismatch. The anastomosis procedure including the size adaptation required 15-25 min. All anastomoses were patent immediately, 5 min after rearterialization and at both harvest time points. The liver lobular architecture was intact in the rearterialized group, whereas a moderate degree of bile duct proliferation and portal/lobular lymphocytic infiltration were observed in the nonarterialized group.

CONCLUSION

The new technique is a time-consuming and microsurgically challenging but universally applicable and robust procedure accommodating even a substantial mismatch in vessel diameter.

Apoptosis: its functions and control in the ocular lens

The ocular lens is a non-vascular and non-innervated transparent organ that plays an important role in vision processing. This unique organ is derived from the embryonic ectoderm of the brain region through a complicated differentiation process in which apoptosis plays a key role. First, when the committed ectoderm becomes thickened and invaginated, the defined number of cells required to form the lens vesicle is partially determined by apoptosis. Second, separation of lens vesicle from the above corneal ectoderm is executed through apoptosis of the lens stalk cells. Finally, differentiation of the lens epithelial cells is controlled by the regulators, most of which are involved in control of apoptosis at multiple signaling steps. The lens is also characterized by continuous growth and differentiation in the adulthood. Through the different stages of growth and differentiation in the adult lens, various stress conditions can induce apoptosis of the lens epithelial cells, leading to eventual non-congenital cataractogenesis. The present review summarizes the current knowledge on the functions and regulators of apoptosis in the ocular lens.

An experiment on the attrition of acid demineralized dentine in vitro

BACKGROUND

A laboratory investigation was designed to test the hypothesis that acids increase the rate of wear caused by attrition on dentine.

METHODS

Dentine sections from 10 teeth were polished, cleaned in an ultrasonic bath and divided into 8 equally sized areas. The occlusal tip of a tooth, placed vertically in a wear machine and loaded at 150 N, was moved against each dentine section for 5000 return strokes with artificial saliva acting as a lubricant. Each dentine section was divided into 8 sections and half randomly immersed in a 1% citric acid solution (pH 2.3) for 20 minutes. The wear regime produced 8 wear scars in total per dentine sample. The volume of each wear scar was measured using a contacting digitizing profilometer.

RESULTS

A total of 80 wear scars were produced with 40 treated with acid and 40 acting as controls. The mean for wear volume of the dentine scars with acid was 4.84 μm(3) (1.38) and for the non-acid surface 2.95 μm(3) (0.86). This difference was statistically significant (p < 0.05).

CONCLUSIONS

These results support the hypothesis that acids increase the rate of wear caused by attrition on dentine.

Diarrhoea during enteral nutrition is predicted by the poorly absorbed short-chain carbohydrate (FODMAP) content of the formula

BACKGROUND

Although it is recognized that diarrhoea commonly complicates enteral nutrition, the causes remain unknown.

AIM

To identify factors associated with diarrhoea in patients receiving enteral nutrition with specific attention to formula composition.

METHODS

Medical histories of in-patients receiving enteral nutrition were identified by ICD-10-AM coding and randomly selected from the year 2003 to 2008. Clinical and demographic data were extracted. Formulas were classified according to osmolality, fibre and FODMAP (fermentable oligo-, di- and mono-saccharides and polyols) content.

RESULTS

Formula FODMAP levels ranged from 10.6 to 36.5 g/day. Of 160 patients receiving enteral nutrition, 61% had diarrhoea. Univariate analysis showed diarrhoea was associated with length of stay >21 days (OR 4.2), enteral nutrition duration >11 days (OR 4.0) and antibiotic use (OR 2.1). After adjusting for influencing variables through a logistic regression model, a greater than five-fold reduction in risk of developing diarrhoea was seen in patients initiated on Isosource 1.5 (P = 0.029; estimated OR 0.18). The only characteristic unique to this formula was its FODMAP content, being 47-71% lower than any other formula.

CONCLUSIONS

Length of stay and enteral nutrition duration independently predicted diarrhoea development, while being initiated on a lower FODMAP formula reduced the likelihood of diarrhoea. As retrospective evaluation does not support a cause-effect relationship, an interventional study investigating FODMAPs in enteral formula is indicated.

First Report of Red Crown Rot Caused by Cylindrocladium parasiticum on Soybean in Guangdong, Southern China

In October 2006, occurrence of a disease on soybean (Glycine max) was observed in Guangdong Province of southern China with symptoms resembling red crown rot (3,4). Reddish brown lesions girdled the basal stems with numerous reddish orange perithecia on the lesion surface. Roots became black and rotted and whole plants wilted and died. More recently, outbreaks of this disease were observed in several counties in Guangdong. Disease incidence reached as much as 80% on cv. Huaxia 3 in some fields, causing severe yield losses. Isolation was made from the edge of lesions on potato dextrose agar at 25°C. The fungus produced white, aerial mycelia and a burnt orange-to-dark brown submerged growth. Conidiophores were borne laterally on a stipe, terminating in a hyaline, globose vesicle measuring 4.0 to 13.0 μm in diameter. After branching from the stipe, the conidiophore continued to develop by forming two to three single-celled branches. These cells might give rise to two or three shorter branches (14.8 to 36.9 μm long) and phialides. The phialides were doliform, nonseptate, and measured 7.4 to 19.7 × 3.7 to 4.9 μm. Conidia were hyaline, cylindrical with one to three septa (mostly three septa), and measured 54.1 to 76.3 × 4.9 to 7.4 μm. Perithecia were orange to red, subglobose to oval or globose, 212.1 to 454.5 μm high, and 111.1 to 333.3 μm wide. Asci were hyaline, clavate, thin walled, long stalked, measured 121.0 to 200.8 × 11.5 to 25.6 μm, and each contained eight ascospores that became aggregated in the upper half of the ascus at maturity. The ascospores were hyaline, fusoid to falcate with one to three septa (mostly with one septum), constricted slightly at the septum, and measured 29.5 to 73.8 × 4.9 to 9.8 μm. The fungus was identified as Cylindrocladium parasiticum (teleomorph Calonectria ilicicola) (1,2). The beta-tubulin gene fragment sequences of three isolates were obtained (one sequence being GenBank Accession No. GU073284) and comparisons with GenBank showed 99 to 100% similarity with Calonectria ilicicola (EF159730 and AY725643). Pathogenicity was confirmed by inoculation of 2-week-old seedlings of cv. Huaxia 3 in plastic pots (10 × 9 cm) by drenching with a conidia suspension (10⁵ conidia per ml). All inoculated plants showed similar red crown rot symptoms on stem bases and roots 1 week after inoculation. C. parasiticum was reisolated from the diseased plants, and many orange-to-red perithecia of Calonectria ilicicola were formed on the lesions 3 weeks after inoculation. This pathogen may pose a serious threat to >300,000 ha of soybean production as well as >300,000 ha of peanut production in Guangdong Province. It has been previously reported in Jiangsu Province in eastern China (3) and Yunnan Province in western China (4). References: (1) D. K. Bell, and E. K. Sobers. Phytopathology 56:1361, 1966. (2) P. W. Crous et al. Mycol. Res. 97:889, 1993. (3) J. Y. Gai et al. Soybean Sci. (in Chinese) 11:113, 1992. (4) Z. H. Ma et al. Plant Pathol. 53:537, 2004.

Protein phosphatase-1 regulates Akt1 signal transduction pathway to control gene expression, cell survival and differentiation

AKT pathway has a critical role in mediating signaling transductions for cell proliferation, differentiation and survival. Previous studies have shown that AKT activation is achieved through a series of phosphorylation steps: first, AKT is phosphorylated at Thr-450 by JNK kinases to prime its activation; then, phosphoinositide-dependent kinase 1 phosphorylates AKT at Thr-308 to expose the Ser-473 residue; and finally, AKT is phosphorylated at Ser-473 by several kinases (PKD2 and others) to achieve its full activation. For its inactivation, the PH-domain containing phosphatases dephosphorylate AKT at Ser-473, and protein serine/threonine phosphatase-2A (PP-2A) dephosphorylates it at Thr-308. However, it remains unknown regarding which phosphatase dephosphorylates AKT at Thr-450 during its inactivation. In this study, we present both in vitro and in vivo evidence to show that protein serine/threonine phosphatase-1 (PP-1) is a major phosphatase that directly dephosphorylates AKT to modulate its activation. First, purified PP-1 directly dephosphorylates AKT in vitro. Second, immunoprecipitation and immunocolocalization showed that PP-1 interacts with AKT. Third, stable knock down of PP-1alpha or PP-1beta but not PP-1gamma, PP-2Aalpha or PP-2Abeta by shRNA leads to enhanced phosphorylation of AKT at Thr-450. Finally, overexpression of PP-1alpha or PP-1beta but not PP-1gamma, PP-2Aalpha or PP-2Abeta results in attenuated phosphorylation of AKT at Thr-450. Moreover, our results also show that dephosphorylation of AKT by PP-1 significantly modulates its functions in regulating the expression of downstream genes, promoting cell survival and modulating differentiation. These results show that PP-1 acts as a major phosphatase to dephosphorylate AKT at Thr-450 and thus modulate its functions.

Molecular genetics of the ubiquitin-proteasome system: lessons from yeast

Our studies with the yeast Saccharomyces cerevisiae have uncovered a number of general principles governing substrate selectivity and proteolysis by the ubiquitin-proteasome system. The initial work focused on the degradation of a transcription factor, the MATalpha2 repressor, but the pathways uncovered have a much broader range of targets. At least two distinct ubiquitination mechanisms contribute to alpha2 turnover. One of them depends on a large integral membrane ubiquitin ligase (E3) and a pair of ubiquitin-conjugating enzymes (E2s). The transmembrane E3 and E2 proteins must travel from their site of synthesis in the ER to the inner nuclear membrane in order to reach nuclear substrates such as alpha2. The 26S proteasome is responsible for alpha2 degradation, and several important features of proteasome assembly and active site formation were uncovered. Most recently, we have delineated major steps in 20S proteasome assembly and have also identified several novel 20S proteasome assembly factors. Surprisingly, alterations in 20S proteasome assembly lead to defects in the assembly of the proteasome regulatory particle (RP). The RP associates with the 20S proteasome to form the 26S proteasome. Our data suggest that the 20S proteasome can function as an assembly factor for the RP, which would make it the first such factor for RP assembly identified to date.

Multiscale modeling of polymers-bridging the molecular continuum divide

A method to reduce the degrees freedom in molecular mechanics simulation is presented. Although the approach is formulated for amorphous materials, it is equally applicable to crystalline materials. The method is selectively applied to regions where molecular displacements are expected to be small while simultaneously using classical molecular mechanics for regions undergoing large deformation. Its accuracy and computational efficiency are demonstrated through the simulation of a polymer-like substrate indented by a rigid indentor. The region directly below the indentor is modelled by classical molecular mechanics while the region further away has the degrees of freedom reduced by about 50 times.

Glass transition temperature influence on crosslinked and entangled polymer interfaces

The influence of glass transition temperature (Tg) on crosslinked and entangled polymer interfaces was investigated using coarse grained molecular dynamics (MD). A crosslinked polymer interface and an entangled polymer interface were built and the Tg for each system were obtained by confining a thin film between two rigid walls. The physical properties of each system above and under Tg were compared. The mechanical properties were also explored by pulling the interfaces apart at different temperature. The results are qualitatively agreed with experimental observations. Furthermore, the present results show that, when under tensile loading at temperature higher than Tg, the entangled interface exhibits strain softening while the crosslinked thin film is still able to show strain hardening. The different performances may due to that, at high temperature, the high mobility of monomers tend to unravel the entangled chain in linear polymer system while in crosslinked system, monomers with high mobility tend to arrest the void and decrease the void propagation.

Interaction of the apolipoprotein E receptors low density lipoprotein receptor-related protein and sorLA/LR11

In this study, we examined protein-protein interactions between two neuronal receptors, low density lipoprotein receptor-related protein (LRP) and sorLA/LR11, and found that these receptors interact, as indicated by three independent lines of evidence: co-immunoprecipitation experiments on mouse brain extracts and mouse neuronal cells, surface plasmon resonance analysis with purified human LRP and sorLA, and fluorescence lifetime imaging microscopy (FLIM) on rat primary cortical neurons. Immunocytochemistry experiments revealed widespread co-localization of LRP and sorLA within perinuclear compartments of rat primary neurons, while FLIM analysis showed that LRP-sorLA interactions take place within a subset of these compartments.

Molecular diversity and evolution of cystine knot toxins of the tarantula Chilobrachys jingzhao

Cystine knot toxins (CKTs) in spider venoms represent a rich source of novel ligands for varied ion channels. Here, we identified 95 novel putative CKT precursors by analyzing expressed sequence tags of the tarantula Chilobrachys jingzhao venom gland. Phylogenetics analyses revealed one orphan family and six families with sequence similarity to known toxins. To further investigate the relationships of their structures, functions and evolution, we assayed 10 representative toxins for their effect on ion channels, and performed structure model comparisons, evolution analysis and toxin distribution analysis. This study revealed two major types of CKTs: pore-blocking toxins and gating modifier toxins. A few blockers were observed with relatively high abundance and wide distribution, which may be a category of original toxins that block channels conserved in various preys with relatively high specificity. The gating modifier families contain advanced toxins, usually have many members and interact with diverse regulatory components of channels.

Endoscope-assisted reduction of long-standing condylar dislocation

Endoscopy is widely used in the diagnosis and treatment of temporomandibular joint disorders. This paper introduces arthro-endoscopy as a new method of treatment for temporomandibular joint dislocation. As this method is minimally invasive, it is suitable for medically compromised patients who cannot tolerate open surgery.

Anti-CD25 treatment and FOXP3-positive regulatory T cells in heart transplantation

The interleukin-2 receptor alpha chain (IL-2Ra, CD25) plays a major part in shaping the dynamics of T cell populations following immune activation, due to its role in T cell proliferation and survival. Strategies to blunt the effector responses in transplantation have been developed by devising pharmaceutical agents to block the IL-2 pathways. However, such strategies could adversely affect the CD25(+)FOXP3(+)T regulatory (T reg) populations which also rely on intereukin-2 signaling for survival. The present study shows that a cohort of heart allograft recipients treated with Daclizumab (a humanized anti-CD25 antibody) display FOXP3 expression patterns consistent with functional T regulatory cell populations. High levels of FOXP3 were observed to correlate with lower incidence of and recovery from acute rejection, as well as lower levels of anti-donor HLA antibody production. Therefore, T reg populations appear fully functional in patients treated with Daclizumab, even when 5 doses were administered. By comparison, patients treated with fewer doses or no Daclizumab had a higher incidence of acute rejection, antibody production and graft failure. Therefore, our data indicates that Daclizumab treatment does not interfere with the generation of regulatory T cells and has a beneficial effect on heart allograft survival.

Protein serine/threonine phosphatase-1 dephosphorylates p53 at Ser-15 and Ser-37 to modulate its transcriptional and apoptotic activities

We have previously demonstrated that the serine/threonine protein phosphatase-1 (PP-1) plays an important role in promoting cell survival. However, the molecular mechanisms by which PP-1 promotes survival remain largely unknown. In the present study, we provide evidence to show that PP-1 can directly dephosphorylate a master regulator of apoptosis, p53, to negatively modulate its transcriptional and apoptotic activities, and thus to promote cell survival. As a transcriptional factor, the function of p53 can be greatly regulated by phosphorylation and dephosphorylation. While the kinases responsible for phosphorylation of the 17 serine/threonine sites have been identified, the dephosphorylation of these sites remains largely unknown. In the present study, we demonstrate that PP-1 can dephosphorylate p53 at Ser-15 and Ser-37 through co-immunoprecipitation, in vitro and in vivo dephosphorylation assays, overexpression and silence of the gene encoding the catalytic subunit for PP-1. We further show that mutations mimicking constitutive dephosphorylation or phosphorylation of p53 at these sites attenuate or enhance its transcriptional activity, respectively. As a result of the changed p53 activity, expression of the downstream apoptosis-related genes such as bcl-2 and bax is accordingly altered and the apoptotic events are either largely abrogated or enhanced. Thus, our results demonstrate that PP-1 directly dephosphorylates p53, and dephosphorylation of p53 has as important impact on its functions as phosphorylation does. In addition, our results reveal that one of the molecular mechanisms by which PP-1 promotes cell survival is to dephosphorylate p53, and thus negatively regulate p53-dependent death pathway.

Effect of Age on Outcomes After Left Ventricular Assist Device Placement

The influence of age on outcomes after left ventricular assist device (LVAD) implantation is not well studied. To address this question, we assessed 222 patients who underwent LVAD placement and were divided into quartiles based on age (years): group 1, <or=44; group 2, 45 to 53; group 3, 54 to 59; and group 4, >or=60. Eighty-four patients died on LVAD support. Six- and 12-month survivals for the four groups of LVAD patients were 67.7, 73.7, 49.8, and 38.2, and 49.4, 57.3, 42.7, and 26.2, respectively (all P<.01). Older patients showed a higher risk of infections, embolic strokes, and respiratory complications. They were the least likely to undergo reoperations postimplantation (56%, 53%, 50%, 46%, P=.06). After adjusting for baseline differences between the groups, there was a trend toward increasing mortality with age, which did not reach significance (odds ratio 1.93; 95% confidence interval 0.95 to 3.92 for the oldest quartile as compared with the youngest). In conclusion, these results suggest in the absence of other high risk factors, age alone should not be used as an independent contraindication for LVAD implantation.

Electrosonographic characteristics of sounds from temporomandibular joint disc replacement

The purpose of this study was to investigate the waveform and electrosonographic characteristics of sounds emanating from internal derangement of the temporomandibular joint (TMJ). TMJ sounds were recorded from 10 joints of normal people (NP), 10 joints from patients with anterior disc displacement with reduction (DDR) and 20 joints from patients with anterior disc displacement without reduction (DDNR). The sounds were analyzed through fast Fourier transfer methods to observe their waveforms and electrosonographic characteristics. The observations were then used in differentially diagnosing internal derangement. Wave pattern and electrosonography (ESG) differed among the NP, DDR and DDNR groups. There was very little difference in frequency between the sounds from DDR and DDNR, but the amplitude of the DDR sounds was higher than those of DDNR and NP. The sensitivity and specificity of ESG diagnosis for DDR were 77.2% and 93.3%, respectively, while for DDNR they were 81.6% and 64.7%, respectively.

Effect of load and temperature on in vitro degradation of poly(glycolide-co-l-lactide) multifilament braids

The effects of load and temperature on in vitro degradation behaviors of poly(glycolide-co-L-lactide) 90/10 multifilament braids were investigated in phosphate buffer solution at pH 7.4. The property changes of the braids with time were monitored by tensile test, gel permeation chromatography analysis, and scanning electron microscopy. The interrelationships between material properties, time and experimental conditions were explored. The results showed that the polymer braids gradually lost their strength and molecular weight with the increasing in vitro time. While the load levels applied had no effect on the materials, raising temperatures significantly accelerated the degradation. It was found that for a given tensile breaking strength retention (BSR), the dependence of degradation time on temperature could be illustrated by an Arrhenius-type equation, from which the activation energy could be derived. Further analysis indicated that there are well-defined relationships between molecular weight, BSR and breaking strain retention, and these relationships can be illustrated mathematically. Finally, the surface morphology of the fiber showed visible change during the degradation process.

Kernel-based data fusion and its application to protein function prediction in yeast

Kernel methods provide a principled framework in which to represent many types of data, including vectors, strings, trees and graphs. As such, these methods are useful for drawing inferences about biological phenomena. We describe a method for combining multiple kernel representations in an optimal fashion, by formulating the problem as a convex optimization problem that can be solved using semidefinite programming techniques. The method is applied to the problem of predicting yeast protein functional classifications using a support vector machine (SVM) trained on five types of data. For this problem, the new method performs better than a previously-described Markov random field method, and better than the SVM trained on any single type of data.