Magnetic resonance imaging and spectroscopy of the rat hippocampus 1 month after exposure to 56Fe-particle radiation

The response of the central nervous system to space radiation is largely unknown. The hippocampus, which is known for its critical role in learning and memory, was evaluated for its response to heavy-ion radiation. At 1 month, animals exposed to brain-only 56Fe-particle irradiation (0-4 Gy) were examined using contrast-enhanced T1 imaging (CET1), T2-weighted imaging (T2WI), diffusion weighted imaging (DWI), and (1)H-magnetic resonance spectroscopy (MRS). Correlative histology was performed after imaging. The T2WI, DWI and CET1 images revealed no overt anatomical changes after irradiation. Quantitative analysis demonstrated a significant increase in T2 at 2 Gy compared to 0 Gy. The apparent diffusion coefficient (ADC) revealed an inverse dose-dependent quantitative change in water mobility. Compared to 0 Gy, the ADC increased 122% at 1 Gy and declined to 44% above control levels at 4 Gy. MRS showed a significant increase in the N-acetylaspartate/choline ratio at 4 Gy and a lactate peak. Histology demonstrated no overt pathological changes in neuronal and astrocyte populations. However, a significant inverse dose-dependent morphological change in the microglial population was detected in irradiated animals. Our results suggest that early tissue matrix modifications induced by 56Fe-particle radiation can be detected by MRI in the absence of evident histopathology. These changes may indicate fundamental changes in the structure and function of the hippocampus.

Genetic and functional characterization of the rice bacterial blight disease resistance gene xa5

Xanthomonas oryzae pv. oryzae is the causal agent of rice bacterial blight, a destructive rice disease worldwide. The gene xa5 provides race-specific resistance to X. oryzae pv. oryzae, and encodes the small subunit of transcription factor IIA. How xa5 functions in bacterial blight resistance is not well understood, and its recessive gene action is disputed. Here we show that xa5 is inherited in a completely recessive manner and the susceptible allele Xa5 is fully dominant. In accordance with this, bacterial growth in heterozygous and homozygous susceptible lines is not significantly different. Further, one allele of Xa5 is sufficient to promote disease in previously resistant plants; additional copies are not predictive of increased lesion length. Surprisingly, a resistant nearly isogenic line (NIL) of an indica variety sustains high levels of bacterial populations compared to the susceptible NIL, yet the resistant plants restrict symptom expression. In contrast, in japonica NILs, bacterial population dynamics differ in resistant and susceptible genotypes. However, both resistant indica and japonica plants delay bacterial movement down the leaf. These results support a model in which xa5-mediated recessive resistance is the result of restricted bacterial movement, but not restricted multiplication.

Stretcher-free high energy nonlinear amplification of femtosecond pulses in rod-type fibers

We report on the study of direct amplification of femtosecond pulses in an 80 mum core diameter microstructured Yb-doped rod-type fiber amplifier in the nonlinear regime. The system includes a compact single grating compressor for the compensation of the small dispersion in the amplifier. With a 1250 line/mm (l/mm) grating-based compressor, pulses as short as 49 fs with 870 nJ pulse energy and 12 MW peak power are obtained. Alternatively, the use of a 1740 l/mm grating allows the production of higher quality pulses of 70 fs, 1.25 microJ pulse energy, and 16 MW peak power.

Evolving Connectionist System Based Role Allocation for Robotic Soccer

Robotic soccer is an intelligent system where a group of mobile robots are controlled to perform soccer play ( http://www.fira.net ). The allocation of a suitable role for each robot in a team is a key for the success of the play. The paper treats this issue as one of pattern classification, and solves it with an Evolving classification function (ECF), a special evolving connectionist system (ECOS). A robot's role is determined by and evolves with the states of system (robots and target) in real time. The software and hardware platforms are set up for data collection and learning. The effectiveness of the proposed approach is verified by the experimental studies.

Alien genetic resources for wheat leaf rust resistance, cytogenetic transfer, and molecular analysis

Wild relatives of wheat are useful sources of alien resistance genes for wheat breeding. The objective of this review is to document research on the evaluation, transfer, and molecular analysis of alien resistance to wheat leaf rust especially in Aegilops tauschii, the diploid D-genome donor of common wheat. Nine named resistance genes (Lr1, Lr2, Lr15, Lr21, Lr22, Lr32, Lr34, Lr39, and Lr42) occur in the D genome. Twelve new leaf rust resistance genes have been documented in Ae. tauschii. The south-west Caspian Sea region is the centre of genetic diversity for seedling resistance. Adult-plant resistance is widespread in all geographic regions and should be exploited more in the future. Lr1 and Lr21 have been cloned and are typical NBS-LRR genes. The recent documentation of cryptic introgressions of Lr57/Yr40 from Ae. geniculata and Lr58 from Ae. triuncialis offers exciting possibilities for transferring alien genes without linkage drag. Both Lr21 and Lr34 presumably arose during or following the origin of common wheat ~8000 years ago. Leaf rust resistance genes often are located towards the physical ends of wheat chromosomes. These regions are known to be high in recombination, and this may explain their rapid rate of evolution.

Pneumocystis colonisation is common among hospitalised HIV infected patients with non-Pneumocystis pneumonia

BACKGROUND

When Pneumocystis DNA is recovered from respiratory specimens of patients without Pneumocystis pneumonia (PCP), patients are said to be colonised with Pneumocystis, although the significance of this state is unknown. Understanding risk factors for and outcomes of colonisation may provide insights into the life cycle and transmission dynamics of Pneumocystis jirovecii.

METHODS

We performed a cross sectional study of the prevalence and clinical predictors of Pneumocystis colonisation in 172 HIV infected, PCP negative inpatients undergoing diagnostic evaluation of 183 episodes of pneumonia at either the Medical Center of Louisiana at New Orleans between 2003 and 2005 or San Francisco General Hospital between 2000 and 2005. DNA was extracted from sputum and bronchoalveolar lavage specimens and amplified using a nested PCR assay at the mitochondrial large subunit (18S) ribosomal RNA locus. Colonisation was deemed present if Pneumocystis DNA was identified by both gel electrophoresis and direct DNA sequencing.

RESULTS

68% (117/172) of all patients were colonised with Pneumocystis. No strong associations with colonisation were identified for any demographic factors. Among clinical factors, having a CD4+ T cell count </=50 cells/mul (unadjusted OR 2.4, 95% CI 1.09 to 5.48; p = 0.031) and using PCP prophylaxis (unadjusted OR 0.55, 95% CI 0.29 to 1.07; p = 0.077) were associated with Pneumocystis colonisation, although the latter association may have been due to chance. After adjustment for CD4+ T cell count, use of PCP prophylaxis was associated with a decreased odds of colonisation (adjusted OR 0.45, 95% CI 0.21 to 0.98; p = 0.045). 11 patients who were colonised were subsequently readmitted for evaluation of a second episode of pneumonia; three were found to be colonised again, but none had PCP.

CONCLUSIONS

The majority of hospitalised HIV infected patients with non-PCP pneumonia are colonised with Pneumocystis. Failure to use co-trimoxazole prophylaxis and severe immunosuppression are associated with an increase in the odds of colonisation. Pneumocystis colonisation among hospitalised patients does not commonly lead to PCP.

Effect of aldrin on life history characteristics of rotifer Brachionus calyciflorus pallas

The organochlorine insecticide aldrin is commonly used in intensive agriculture, and demonstrates estrogenic activity. Rotifers such as Brachionus calyciflorus are favored test animals in aquatic toxicology because of their more sensitivity to most toxicants. In the tested concentration range of 0.04-1.28 mg/L, aldrin shortened significantly the durations of embryonic development. Lower concentrations of aldrin had an intriguing effect on the reproduction of the rotifers and are beneficial to their survival. Different endpoints of both development and reproduction had different sensitivity to aldrin. The reproductive endpoint of the rotifers is more sensitive to aldrin than the developmental endpoint.

Imaging beyond the Born approximation: an experimental investigation with an ultrasonic ring array

The classical diffraction limit excludes the possibility of resolving features of an object which are spaced less than half a wavelength apart when scattering experiments are performed from the far field. However, recently it has been shown that this limit could be a consequence of the Born approximation that neglects the distortion of the probing wave as it travels through the object to be imaged. Such a distortion, which is due to the multiple scattering phenomenon, can encode unlimited resolution in the radiating component of the scattered field thus leading to super resolution. In this context, a resolution better than lambda/3 has been reported in the case of elastic wave probing [F. Simonetti, Phys. Rev. E 73, 036619 (2006)], lambda being the wavelength of the wave illuminating the object. This paper demonstrates a resolution better than lambda/4 and approaching lambda/6 for objects immersed in a water bath probed by means of a ring transducer array that excites and detects ultrasonic pressure waves in a full view configuration. This is achieved despite the presence of a high level of noise in the measurements (the signal to noise ratio was below 0 dB). Moreover, while previous papers have provided experimental evidence of super resolution for objects small compared to the wavelength, here the case of extended objects is also investigated.

Characterization of the porcine insulin-like growth factor-binding protein, acid-labile subunit gene: full-length cDNA and DNA sequence, polymorphisms and expression profile

Insulin-like growth factor-binding protein acid-labile subunit (IGFALS) is an important glycoprotein in the circulation complex for insulin-like growth factors-I and -II (IGFs). So far only a partial porcine IGFALS sequence is available. We herein report the isolation, characterization, polymorphism identification and expression analysis of the porcine IGFALS gene. A 2000-bp full-length cDNA sequence was determined with 5'- and 3'-Rapid Amplification of cDNA End (RACE) assay. It contains a 1821-bp open reading frame encoding a protein of 606 amino acids with a calculated molecular mass of 66 kDa and a theoretical isoelectric point of 6.89. The deduced IGFALS protein shares high identity (70-80%) with other mammalian IGFALS. We also obtained a full-length genomic DNA sequence of the gene. Similar to the other mammalian orthologues, particularly in terms of exon size and exon/intron boundaries, the porcine IGFALS gene spans a transcription unit of 2990 bp, consisting of two exons and one intron. Three single nucleotide polymorphisms (synonymous mutations) were identified in the DNA sequence. RT-PCR assays indicate that IGFALS is expressed ubiquitously in pigs and transcripts are particularly abundant in the liver, lung, white adipose tissue, prostate, epididymis, thyroid and bladder.

Distribution and expression of transgene green fluorescent protein in mice survived up to four weeks following in utero gene therapys

Gene replacement offers a potential cure for degenerative disorders caused by a single gene deletion or mutation. Diagnoses of monogenic disorders in the fetus enable prenatal gene replacement which may be beneficial from the perspectives of host inflammatory/immune response, efficacy and disease prevention. Purpose: To evaluate the distribution and expression of reporter gene green fluorescent protein (GFP) in the tissues of mice survived up to one month following in utero gene therapy. Methods: Vesicular Stomatitis Virus-G (VSV-G) pseudotyped lentiviral (LV) vector containing GFP was prepared via triple plasmid co-transfection. Time-mated CD-1 mice underwent individual amniotic sac injection with either 1x106 LV particles or saline (controls) on gestational day 16 (term=21d), and were allowed to undergo spontaneous parturition. Pups were sacrificed on postnatal days 0, 7, 21 and 28, and neonatal and maternal tissues were analyzed for GFP transgene (by DNA polymerase chain reaction; PCR), and transgene expression by quantitative reverse transcriptase (QRT) PCR and immunohistochemistry (IHC). Results: We observed selective transduction of neonatal tissues (trachea, lung, liver, heart, kidney, spleen, intestine, skeletal muscle), in pups undergoing in utero transfection with LV-GFP. Maternal tissues did not contain transgene despite exposure during amniotic injection. Although the numbers of pups analyzed at each postnatal time point was small, we observed variable persistence of GFP expression that appeared to be tissue specific (with persistent expression noted in intestine of 4 week old pups). Conclusions: Neonatal tissue transfection occurs in a variety of tissues following amniotic injection with LV-GFP in this murine model of in utero gene therapy. Transgene persistence and expression patterns observed over the first 4 weeks of life may reflect tissue-specific genomic insertion of transgene that favors persistent transcription in select tissues.

Characterization of polymorphisms of transferrin receptor and their association with susceptibility to ETEC F4ab/ac in pigs

Diarrhoea caused by enterotoxigenic Escherichia coli (ETEC) expressing F4 (F4ab, F4ac and F4ad) fimbriae is a significant cause of mortality and morbidity in newborn and weaned pigs. The locus controlling susceptibility towards ETEC F4ab/ac has been mapped to SSC13q41, in which TFRC (transferrin receptor) was localized and considered as a positional candidate gene for ETEC F4ab/ac receptor. In this study, we determined susceptibility/resistance to ETEC F4ab/ac in a total of 755 F2 animals from a White Duroc x Erhualian intercross using a microscopic enterocyte adhesion assay. We identified two TFRC polymorphisms (SNPs 591 A>G and 632 A>G) in a single exon after comparative sequencing analysis of 2371-bp amplicons containing the complete coding region of TFRC using RNA of eight full-sib F2 animals with susceptible and resistant phenotypes. The intron sequences flanking the two exon polymorphisms were obtained, revealing an intron polymorphism (SNP 291 C>T). We genotyped the 19 founder animals of the White Duroc x Erhualian intercross for the identified polymorphisms, showing that only the 291 C>T polymorphism is a highly informative marker. We further genotyped all 59 F1 and 755 F2 animals for the 291 C>T polymorphism, and the association of this polymorphism with susceptibility/resistance to ETEC F4ab/ac in these F2 animals was evaluated by the transmission disequilibrium test. The result showed that the 291 C>T polymorphism is not a causal mutation, however, has a significant linkage disequilibrium with the ETEC F4ab/ac, especially F4ac receptor locus.

Improvement of insulin sensitivity and beta-cell function by nateglinide and repaglinide in type 2 diabetic patients - a randomized controlled double-blind and double-dummy multicentre clinical trial

AIM

To evaluate the efficacy of nateglinide vs. repaglinide in blood glucose (BG) control and the effect on insulin resistance and beta-Cell function in patients with type 2 diabetes.

METHODS

A randomized controlled double-blind and double-dummy multicentre clinical trial was conducted. A total of 230 Chinese patients with type 2 diabetes were enrolled in five clinical centres. The patients were divided randomly into group A [repaglinide 1.0 mg three times daily (t.i.d.), n = 115] or group B (nateglinide 90 mg t.i.d., n = 115). At baseline and end of the 12-week clinical trial, standard mixed meal tolerance tests were performed.

RESULTS

A total of 223 patients (96.9%) completed the trial. There was no significant difference between repaglinide and nateglinide groups in the effects of reducing fasting blood glucose (FBG), 30-, 60- and 120-min BG during 12 weeks (p > 0.05). At week 12, no significant difference was shown between the two groups in BG or haemoglobin A(1c) (HbA(1c)) (p > 0.05). However, the effect on HbA(1c) in repaglinide group was stronger than that in nateglinide group (p < 0.05). After 12-week treatment, area under the curve (AUC) of BG decreased (p < 0.05), and AUC of insulin and C-peptide (CP) increased in both groups (p < 0.05). The effects of nateglinide on AUC of BG, insulin and CP were similar to that of repaglinide (p > 0.05). There was no significant difference between the two groups in AUC of BG, insulin or CP in week 12 (p > 0.05). Furthermore, homeostasis model assessment of insulin resistance (HOMA-IR) and beta-cell function indexes measured by HOMA-beta, DeltaI(30)/DeltaG(30) and (DeltaI(30)/DeltaG(30))/HOMA-IR were improved significantly in both groups during 12 weeks (p < 0.05). The effects of improving HOMA-IR and beta-cell function indexes in nateglinide group were comparable with that of repaglinide group (p > 0.05).

CONCLUSIONS

The efficacy of repaglinide and nateglinide in FBG, postprandial glucose excursion and early-phase insulin secretion is similar. But the effect of repaglinide 1.0 mg t.i.d. on HbA(1c) is stronger than that of nateglinide 90 mg t.i.d.. This trial had shown that nateglinide and repaglinide could comparably improve insulin sensitivity and beta-cell function.

Melatonin reduced volume of cerebral infarct induced by photothrombosis in wild-type mice, not in Cyclooxygenase-1 gene knockout mice

Cyclooxygenase (COX) is crucial in inflammation and plays important role in cerebral ischemia. Antiinflammatory effects of melatonin have been verified in previous studies. In this study, cerebral blood flow (CBF) was monitored during operation, infarct volume (IFV) was determined with 5-triphenyltetrazolium chloride (TTC) staining and MR image, and neurological functions were evaluated with turn in an alley and fall pole test in both COX1-gene knockout and wide-type mice with or without melatonin administration 3 days after photothrombosis. CBF reduction, IFV and neurological deficits were not significantly different in COX-1 wild-type and COX-1 knockout mice. Melatonin (15 mg/kg) intraperitoneal injection decreased the CBF reduction, IFV and the latency to turn in an alley in COX-1 wide-type mice, whereas the neuroprotective effect of melatonin was attenuated in COX-1 knockout mice. We concluded that melatonin reduced susceptibility to photothrombotic stroke. COX-1 gene knockout does not alter the susceptibility to cerebral ischemia caused by photothrombosis. COX-1 plays an important role in the pathway of the protection of melatonin.

Nucleofection is highly efficient for transfecting genes into murine embryonic palatal mesenchymal cells in primary culture

Non-syndromic cleft of the lip and/or palate is one of the most common birth defects in humans. Embryonic palatal mesenchymal (EPM) cells are an attractive source for investigating embryonic palatal development. In this study, we developed a highly efficient transfection method for murine EPM (MEPM) cells. MEPM cells were transfected with the plasmid pEGFP-N1 using two non-viral methods: nucleofection and lipofection. Nucleofection provided a much better rate of gene transfer than lipofection particularly in MEPM cells. The methylenetetrahydrofolate reductase (MTHFR) gene is an important candidate for involvement in the pathogenesis of this birth defect. The RNA interference plasmid of MTHFR was constructed and nucleofected into MEPM cells. Successful transfection resulted in a remarkable reduction in the expression of MTHFR. Taken together, the results indicate that nucleofection is highly efficient for MEPM cell transfection, and that this approach may be useful for investigating gene function in the process of palatogenesis.

Stem cell strategies in burns care

The prospect of being able to replace damaged tissue by the process of regeneration would dramatically and irrevocably change the impact, management and outcome of burns. The current understanding of stem cell-based modulation and therapy together with their potential developments do bring this prospect ever closer to a clinical reality. This paper gives a background to stem cell strategies in burns care and identifies actual or prospective applications which, collectively, will forever change burns care throughout the world.