Measurement of xenon diffusing capacity in the rat lung by hyperpolarized 129Xe MRI and dynamic spectroscopy in a single breath-hold.

We used the dual capability of hyperpolarized 129Xe for spectroscopy and imaging to develop new measures of xenon diffusing capacity in the rat lung that (analogously to the diffusing capacity of carbon monoxide or DLCO) are calculated as a product of total lung volume and gas transfer rate constants divided by the pressure gradient. Under conditions of known constant pressure breath-hold, the volume is measured by hyperpolarized 129Xe MRI, and the transfer rate is measured by dynamic spectroscopy. The new quantities (xenon diffusing capacity in lung parenchyma (DLXeLP)), xenon diffusing capacity in RBCs (DLXeRBC), and total lung xenon diffusing capacity (DLXe)) were measured in six normal rats and six rats with lung inflammation induced by instillation of fungal spores of Stachybotrys chartarum. DLXeLP, DLXeRBC, and DLXe were 56 +/- 10 ml/min/mmHg, 64 +/- 35 ml/min/mmHg, and 29 +/- 9 ml/min/mmHg, respectively, for normal rats, and 27 +/- 9 ml/min/mmHg, 42 +/- 27 ml/min/mmHg, and 16 +/- 7 ml/min/mmHg, respectively, for diseased rats. Lung volumes and gas transfer times for LP (TtrLP) were 16 +/- 2 ml and 22 +/- 3 ms, respectively, for normal rats and 12 +/- 2 ml and 35 +/- 8 ms, respectively, for diseased rats. Xenon diffusing capacities may be useful for measuring changes in gas exchange associated with inflammation and other lung diseases.     

Codon 178 mutation of the human prion protein gene in a German family (Backer family): sequencing data from 72-year-old celloidin-embedded brain tissue

Familial Creutzfeldt-Jakob disease was first described in a family from northern Germany in the 1920s (Backer family). PCR amplification of DNA extracted from brain tissue embedded in celloidin 72 years ago shows a GAC to AAC substitution at codon 178 of the prion protein gene. This mutation is associated with fatal familial insomnia and familial Creutzfeldt-Jakob disease in a number of families of diverse ethnic background.     

Polymorphism p53 codon-72 and invasive cervical cancer: a meta-analysis.

OBJECTIVES: Although some studies have reported that the arginine isoform on codon 72 of p53 increases the susceptibility to invasive cervical cancer, such data remain controversial. The objective of this study was to quantitatively summarize the evidence for such a relationship. METHODS: Our data sources consisted of a MEDLINE search of the literature published before December 2002, bibliography review, and expert consultation. Thirty-seven studies met the inclusion criteria. Information on sample size, study design, Hardy-Weinberg equilibrium, and method of genotype determination was abstracted by two reviewers using a standardized protocol. The overall odds ratio (OR) of the p53 gene on invasive cervical cancer was estimated using the Mantel-Haenzel method. RESULTS: The overall OR (95% confidence interval) for cervical cancer among those with the homozygous mutant (Arg/Arg) was 1.2 (1.1-1.3, P=0.001) compared with those with the heterozygous mutant (Arg/Pro). By a cellular type of cervical cancer, the overall OR among those with Arg/Arg was statistically significant in adenocarcinomas (1.7, 1.1-2.6, P=0.024), but not in squamous cell carcinomas (1.1, 0.9-1.2, P=0.960), compared with Pro/Pro. Compared with Arg/Pro, the OR among those with Arg/Arg was statistically significant in HPV types 16 (1,5, 1.2-2.0, P=0.002). CONCLUSIONS: Overall, the p53 gene was associated with increased risk for invasive cervical cancer. However, the risk varied by country, cellular, and HPV type.     

基因测序确认一例新β地中海贫血基因突变CD112（T→A）

目的 报道1例中国人少见的β地中海贫血基因突变CD112（T→A）／N。方法 根据血常规平均红细胞体积（MCV）和平均血红蛋白含量（MCH）以及血红蛋白电泳的HbF和HbA2对婚检和产检患者筛查地中海贫血，对可疑β地中海贫血患者采用基因扩增反向点杂交法检测常见17个位点突变。对于未发现突变者采用基因测序。结果 患者携带一种中国人少见的B地贫基因突变CD112（T→A）。结论 β地贫基因CD112（T→A）突变的报道丰富了中国人β地贫突变谱。对于指导婚检、产检、遗传咨询具有重要价值。     

MicroRNA155 Plays a Critical Role in the Pathogenesis of Cutaneous Leishmania major Infection by Promoting a Th2 Response and Attenuating Dendritic Cell Activity

Interferon (IFN)-γ is indispensable in the resolution of cutaneous leishmaniasis (CL), while the Th2 cytokines IL-4, IL-10, and IL-13 mediate susceptibility. A recent study found that miR155, which promotes CD4⁺ Th1 response and IFN-γ production, is dispensable in the control of Leishmania donovani infection. Here, the role of miR155 in CL caused by L. major was investigated using miR155-deficient (miR155^−/−) mice. Infection was controlled significantly quicker in the miR155^−/− mice than in their wild-type (WT) counterparts, indicating that miR155 contributes to the pathogenesis of CL. Faster resolution of infection in miR155^−/− mice was associated with increased levels of Th1-associated IL-12 and IFN-γ and reduced production of Th2- associated IL-4, IL-10, and IL-13. Concentrations of IFN-γ⁺CD8⁺ T cells and natural killer cells in draining lymph nodes were significantly higher in the L. major−infected miR155^−/− mice than in the infected WT mice, as indicated by flow-cytometry. After in vitro IFN-γ stimulation, nitric oxide and IL-12 production were increased, IL-10 production was decreased, and parasite clearance was enhanced in L. major−infected miR155^−/− DCs compared to those in WT DCs. Furthermore, IFN-γ production from activated miR155^−/− T cells was significantly enhanced in L. major−infected miR155^−/− DCs. Together, these findings demonstrate that miR155 promotes susceptibility to CL caused by L. major by promoting Th2 response and inhibiting DC function.

Leishmania are obligate intracellular protozoans that infect phagocytes and cause a spectrum of clinical diseases such as cutaneous leishmaniasis (CL) and visceral leishmaniasis. Common in the tropical and subtropical regions, leishmaniasis affects over 1 billion people worldwide, with an incidence of up to 1 million cases per year.¹ CL is the most common type of Leishmania infection, manifesting as localized skin lesions that can become chronic, leading to significant tissue destruction and disfigurement.^2,3 It is well documented that the induction of a Th1 response and interferon (IFN)-γ are indispensable in the resolution of CL caused by Leishmania major,⁴ whereas disease progression is associated with the induction of a Th2 response and the production of cytokines such as IL-4 and IL-10.⁵ Establishing a disease-resolving response in the host is largely dependent on the ability to mount an appropriate Th1 immune response.⁴ Crucial in this response is the stimulation and activation of DCs that direct T-cell proliferation and differentiation toward IFN-γ–producing Th1 cells.^6,7 In addition to activating of phagocytic cells, IFN-γ induces the production of reactive nitrogen species, specifically nitric oxide (NO), leading to enhanced parasite clearance.⁴miR155 is a recognized regulator of immune cell function and immune response. miR155 enhances macrophage and DC activation and induces inflammatory response,^8,9 and up-regulation of miR155 in CD4⁺ T cells promotes preferential Th1 differentiation and IFN-γ production¹⁰ by suppressing the expression of suppressor of cytokine signaling (SOCS)-1.11, 12, 13, 14 Conversely, miR155 gene–deficient mice exhibit diminished levels of Th1/Th17 cells, macrophages, and DCs.¹⁵ miR155 has also been shown to play a role in regulating effector Th2 response.16, 17, 18 Collectively, these findings suggest that miR155 regulates both Th1 and Th2 responses, which control the outcome of CL caused by L. major. Therefore, the role of miR155 in immunity to L. major using miR155^−/− mice was investigated in the present study. The findings show that miR155 is not required for the induction of a Th1 response and IFN-γ in L. major infection. Rather, miR155 plays a disease-exacerbating role in CL by attenuating DC function and Th1 response and promoting Th2 response.     

Codon optimization of the human papillomavirus 11 (HPV 11) L1 gene leads to increased gene expression and formation of virus-like particles in mammalian epithelial cells

The 505 amino acid L1 protein of the human papillomavirus type 11 (HPV 11) is the major capsid polypeptide that has been shown to self-assemble into virus-like particles (VLPs) in vivo and in vitro. While L1 is essential for viral infection, expression studies in mammalian cells have been hampered by different codon preference between the virus and its host. To optimize L1 gene expression in mammalian cells, we converted wild-type HPV 11 L1 (11 L1wt) codons to those more common in human genes. The modified HPV 11 L1 gene (11 L1h) generated protein levels that were at least 100-fold higher than those of wild-type HPV 11 L1, while no obvious differences were seen in the level of mRNA. HPV 11 L1 protein was detected in mammalian epithelial and fibroblast cells, by immunoblotting and indirect immunofluorescence (IIF) techniques. Unlike the situation in situ, IIF revealed the presence of L1 mainly at perinuclear sites. Virus-like particles assembled intranuclearly only to a low extent, as indicated by transmission electron microscopy. DNA vaccination using the HPV 11 L1h gene yielded a drastic increase in L1-specific antibody production in mice as compared to immunization with the wild-type gene.     

A new gene encoding tRNAPro (GGG) is present in the chloroplast genome of black pine: a compilation of 32 tRNA genes from black pine chloroplasts

The chloroplast genome of black pine (Pinus thumbergii), a gymnosperm, contains 32 different tRNA genes, 30 of which correspond to those previously identified in tobacco and rice chloroplast genomes. Two additional genes encode tRNA^Pro (GGG) and tRNA^Arg (CCG); the former is newly identified while the latter is present in liverwort, Physcomitrella patens and Angiopteris lygodiifolia, chloroplast genomes. Moreover, a partial copy of the split tRNA^Gly (UCC) gene and full copies of tRNA^His (GUG), tRNA^Thr (GGU) and tRNA^Ser (GCU) genes are present in the large single-copy region of the genome, suggesting extensive rearrangements of the chloroplast genome during evolutio. No tRNA genes whose tRNA products can recognize codons CUU/C (Leu) and GCU/C (Ala) have been found. We propose that the 32 tRNAs are sufficient to read all the 61 sense codons in the black pine system using the two-out-of-three and the U:N wobble mechanisms.     

Ethnic variation in the HER-2 codon 655 genetic polymorphism previously associated with breast cancer

HER-2, a protooncogene located on chromosome 17q21, encodes a transmembrane glycoprotein (p185) with tyrosine kinase activity. Alterations of the HER-2 gene have been implicated in the carcinogenesis and prognosis of breast cancer and other solid tumors. It is also a cancer-therapeutic target for antibody-based therapy against the HER-2 protein. A single-nucleotide polymorphism (SNP) at codon 655, resulting in a G-to-A transition (Ile655Val) in the transmembrane domain-coding region of this gene has been associated with an increased risk of breast cancer, particularly among younger women. To understand the importance of this finding throughout the world, we evaluated this polymorphism in Ghanaian, Kenyan, Sudanese, Caucasian, African–American, Saudi, and Filipino subjects using a polymerase chain reaction-restriction fragment length polymorphism assay. The frequency of the Val allele, which is associated with increased breast cancer risk, was highly variable between populations (0%–24%). Continental African populations had a lower frequency of the Val allele than did Saudi, Chinese, Filipino, Caucasian, and African–American subjects. The data suggest that this SNP has variable frequency in different ethnic groups. The findings in this study correspond with the lower incidence and lower risk of breast cancer in African women compared with Caucasian and African–American women. Received: December 13, 2001 / Accepted: January 16, 2002     

Codon volatility does not reflect selective pressure on the HIV-1 genome

Codon volatility is defined as the proportion of a codon's point-mutation neighbors that encode different amino acids. The cumulative volatility of a gene in relation to its associated genome was recently reported to be an indicator of selection pressure. We used this approach to measure selection on all available full-length HIV-1 subtype B genomes in the Los Alamos HIV Sequence Database, and compared these estimates against those obtained via established likelihood- and distance-based comparative methods. Volatility failed to correlate with the results of any of the comparative methods demonstrating that it is not a reliable indicator of selection pressure.     

Hyperbaric oxygenation induced tolerance against focal cerebral ischemia in mice is strain dependent

SV129 or C57BL/6 mice were exposed to hyperbaric oxygenation (HBO, 5 days, 1 h every day, 100% O(2) at 3 atm absolute). One day after the 5th HBO session focal cerebral ischemia was induced. In SV129 mice, HBO induced tolerance against permanent focal cerebral ischemia (n=42, mean infarct volume reduction 27%, P=0.001), but not against transient (30 or 60 min) focal cerebral ischemia. In the C57BL/6 strain of mice, HBO did not induce tolerance against focal cerebral ischemia, even when the duration of ischemia or the HBO protocol were modified. For the first time we demonstrate that HBO can induce tolerance to focal cerebral ischemia, but this effect is strain dependent.