病原菌多重耐药与生物膜表型和毒力因子的相关性

本文旨在研究导尿管相关尿路感染病原菌多重耐药与生物膜表型和毒力因子的相关性。选取2018年1月至2019年12月于沈阳市第四人民医院住院期间出现导尿管相关尿路感染的患者为研究对象,收集尿液培养标本,使用全自动微生物鉴定仪和纸片扩散法进行菌株鉴定和药敏试验。根据药敏试验结果,将大肠埃希菌分为多重耐药组和非多重耐药组。紫外分光光度法测定多重耐药组和非多重耐药组大肠埃希菌的生物膜附着力。PCR法分析多重耐药组和非多重耐药组参与大肠埃希菌4种毒力因子(黏附素、保护素、细胞毒素、铁载体)编码的16种基因表达水平。 共收集156例患者的尿液,并从尿液培养标本中分离出病原菌172株,其中大肠埃希菌97株（56.7%）占比最多。药敏试验结果显示,多重耐药组大肠埃希菌对各类抗菌药物的耐药率均超过60%。与非多重耐药组相比,多重耐药组大肠埃希菌生物膜阳性率差异有统计学意义（P<0.05）,附着力强度等级差异也有统计学意义（P<0.05）。多重耐药组大肠埃希菌与黏附素相关4种毒力基因fimH、sfa、afa、iha表达明显高于非多重耐药组,差异具有统计学意义(P<0.05)。导尿管相关尿路感染病原菌的多重耐药与毒力因子参与产生强附着力生物膜表型有关。     

Platelet-derived growth factor receptor-α cells in mouse urinary bladder: a new class of interstitial cells

Specific classes of interstitial cells exist in visceral organs and have been implicated in several physiological functions including pacemaking and mediators in neurotransmission. In the bladder, Kit(+) interstitial cells have been reported to exist and have been suggested to be neuromodulators. More recently a second interstitial cell, which is identified using antibodies against platelet-derived growth factor receptor-α (PDGFR-α) has been described in the gastrointestinal (GI) tract and has been implicated in enteric motor neurotransmission. In this study, we examined the distribution of PDGFR-α(+) cells in the murine urinary bladder and the relation that these cells may have with nerve fibres and smooth muscle cells. Platelet-derived growth factor receptor-α(+) cells had a spindle shape or stellate morphology and often possessed multiple processes that contacted one another forming a loose network. These cells were distributed throughout the bladder wall, being present in the lamina propria as well as throughout the muscularis of the detrusor. These cells surrounded and were located between smooth muscle bundles and often came into close morphological association with intramural nerve fibres. These data describe a new class of interstitial cells that express a specific receptor within the bladder wall and provide morphological evidence for a possible neuromodulatory role in bladder function.     

Comparison of biomarkers in workers exposed to 2,4,6-trinitrotoluene

2,4,6-Trinitrotoluene (TNT) is an important occupational and environmental pollutant. In TNT-exposed humans, notable toxic manifestations have included aplastic anaemia, toxic hepatitis, cataracts, hepatomegaly, and liver cancer. Therefore, methods were developed to biomonitor workers exposed to TNT. The workers were employed in a typical ammunition factory in China. The external dose (air levels and skin exposure), the internal dose (urinary metabolites), the biologically effective dose (haemoglobin adducts, urinary mutagenicity), biological effects (chromosomal aberrations and health effects), and individual susceptibility (genotypes of xenobiotic-metabolizing enzymes) were determined. Haemoglobin-adducts of TNT, 4-amino-2,6-dinitrotoluene (4ADNT) and 2-amino-4,6-dinitrotoluene (2ADNT), and the urinary metabolites of TNT, 4ADNT and 2ADNT, were found in all workers and in some controls. The levels of the haemoglobin-adducts or the urinary metabolites correlated weakly with the skin or air levels of TNT. The urinary mutagenicity determined in a subset of workers correlated strongly with the levels of 4ADNT and 2ADNT in urine. The haemoglobin-adducts correlated moderately with the urinary metabolites and with the urinary mutagenicity. The genotypes of glutathione S-transferases (GSTM1, GSTT1, GSTP1) and N-acetyltransferases (NAT1, NAT2) were determined. In general, the genotypes did not significantly influence the haemoglobin-adduct levels and the urine metabolite levels. However, TNT-exposed workers who carried the NAT1 rapid acetylator genotype showed an increase in urinary mutagenicity and chromosomal aberrations as compared with slow acetylators. The haemoglobin adduct 4ADNT was significantly associated with a risk of hepatomegaly, splenomegaly and cataract; urine metabolites and genotypes were not associated with health effects. These results indicate that a set of well-selected biomarkers may be more informative regarding exposure and effect than routinely performed chemical measurements of pollutants in the air or on the skin.     

鲁西平原黑线仓鼠种群调节机理的研究——种群密度与肾上腺、性腺重量及血浆皮质醇值之间的关系

关于种群数量波动的内在调节机制,现今已有大量的实验种群资料证明大多数小型啮齿类种群具有内部调节的反馈系统,但对自然种群的研究至今报道较少,涉及的鼠种为数不多,其中关于Christian(1964)的行为-内分泌     

Alternative stress indicators in sea bass Dicentrarchus labrax, L.

Stress indicators (plasma cortisol, glucose and lactate) were evaluated in sea bass Dicentrarchus labrax submitted to different pre-slaughter conditions, and cortisol levels in plasma were found to correlate with those detected in mucus, gut contents and muscle. The results demonstrate new possibilities for monitoring stress status in fishes in which blood sampling is difficult or impossible.     

Selenium suppressed the LPS-induced inflammation of bovine endometrial epithelial cells through NF-κB and MAPK pathways under high cortisol background

The bovine uterus is susceptible to infection, and the elevated cortisol level due to stress are common in cows after delivery. The essential trace element selenium plays a pivotal role in the antioxidant and anti-inflammatory defence system of body. This study investigated whether selenium supplementation protected endometrial cells from inflammation in the presence of high-level cortisol. The primary bovine endometrial epithelial cells were subjected to Escherichia coli lipopolysaccharide to establish cellular inflammation model. The gene expression of inflammatory mediators and proinflammatory cytokines was measured by quantitative PCR. The key proteins of NF-κB and MAPK signalling pathways were detected by Western blot and immunofluorescence. The result showed that pre-treatment of Na₂SeO₃ (1, 2 and 4 μΜ) decreased the mRNA expression of proinflammatory genes, inhibited the activation of NF-κB and suppressed the phosphorylation of extracellular signal-regulated kinase, P38MAPK and c-Jun N-terminal kinase. This inhibition of inflammation was more apparent in the presence of high-level cortisol (30 ng/mL). These results indicated that selenium has an anti-inflammatory effect, which is mediated via NF-κB and MAPK signalling pathways and is augmented by cortisol in bovine endometrial epithelial cells.     

Identification of therapeutic peptide scaffold from tritrpticin family for urinary tract infections using in silico techniques

Abstract

Antimicrobial peptides (AMPs) like tritrpticins, exhibit non-specific membrane lysis of gram-negative bacteria and can replace antibiotics, combating multi-drug resistance observed in UTI patients. Tritrpticins designated – NT, T1, T2, T3, T5, T7 and T8, were computationally investigated by interaction with Escherichia coli membrane model, mammalian cell toxicity and structural stability to identify a potential drug scaffold for UTI. Initially T3 was eliminated due to low interaction with Escherichia coli membrane model, based on its computed solvation energy. Further, negative support vector machine (SVM) scores revealed non-toxicity of T1, T2, T5, T7 and T8. Finally, at 310?K and varying pH 4.5–9.0, T5 exhibited highest structural stability based on its highest consistency of hydrogen bonds (H-bonds), root mean square deviation (RMSD) and secondary structure profiles along with its lowest conformational free energy. Overall, T5 could be considered a promising peptide drug scaffold to combat UTI.

ABBREVIATIONS AMP antimicrobial peptide

PBEQ Poisson Boltzmann equation

H-bonds hydrogen bonds

MIC minimum inhibitory concentration

LD50 lethal dose, 50%

RMSD root mean square deviation

SVM support vector machine

UTI urinary tract infection

Communicated by Ramaswamy H. Sarma     

Effects of global warming on sex ratios in fishes

In fishes, sex is determined by genetics, the environment or an interaction of both. Temperature is among the most important environmental factors that can affect sex determination. As a consequence, changes in temperature at critical developmental stages can induce biases in primary sex ratios in some species. However, early sex ratios can also be biased by sex-specific tolerances to environmental stresses that may, in some cases, be amplified by changes in water temperature. Sex-specific reactions to environmental stress have been observed at early larval stages before gonad formation starts. It is therefore necessary to distinguish between temperature effects on sex determination, generally acting through the stress axis or epigenetic mechanisms, and temperature effects on sex-specific mortality. Both are likely to affect sex ratios and hence population dynamics. Moreover, in cases where temperature effects on sex determination lead to genotype–phenotype mismatches, long-term effects on population dynamics are possible, for example temperature-induced masculinization potentially leading to the loss of Y chromosomes or feminization to male-biased operational sex ratios in future generations. To date, most studies under controlled conditions conclude that if temperature affects sex ratios, elevated temperatures mostly lead to a male bias. The few studies that have been performed on wild populations seem to confirm this general trend. Recent findings suggest that transgenerational plasticity could mitigate the effects of warming on sex ratios in some populations.     

Investigations into the chirality of the metabolic sulfoxidation of cimetidine

The individual enantiomers of cimetidine sulfoxide were resolved by preparative chromatography using a Chiralcel OC stationary phase and were characterized by the determination of optical rotation and circular dichroism spectra. Cimetidine sulfoxide was isolated from the urine of two healthy male volunteers following oral administration of cimetidine (400 mg). Urine was collected every 2 h for 12 h postdosing, after which time HPLC analysis indicated negligible recovery of the drug as the sulfoxide. Some 7% of the dose was recovered as cimetidine sulfoxide over this period. The enantiomeric composition of cimetidine sulfoxide was determined by sequential achiral—chiral chromatography using the OC phase. Over the collection period the enantiomeric ratio was found to be constant in all samples at (+/?) of 71 ± 2.5:29 ± 2.5. The enantiomeric composition of cimetidine sulfoxide was also determined in rat urine (24 h) following the administration of cimetidine (30 mg/kg po) to male Wistar rats (n = 7). The enantiomeric ratio in this case was found to be (+/?) 57 ± 2.3:43 ± 2.3. These preliminary data indicate that sulfoxidation of cimetidine is stereoselective with respect to the (+)-enantiomer and that species variation in enantiomeric composition occurs. © 1994 Wiley-Liss, Inc.     

Detection of Legionella pneumophila serogroup 1 urinary antigen using an enhanced chemiluminescence ELISA

An enhanced chemiluminescence enzyme-linked immunosorbent assay has been developed for the detection of soluble antigen in the urine of patients with Legionnaires' disease (LD). In the assay antigen(s) in the urine samples are captured by a rabbit anti-L. pneumophila antibody coated onto microtitre strips. A fluorescein-isothiocyanate (FITC) conjugate of the same antibody is then added which binds to the captured antigen. Any immobilized FITC-labelled antibody is then detected with a horseradish peroxidase (HRP) conjugate of a monoclonal anti-FITC antibody. HRP activity is monitored after oxidation of luminol in the presence of H₂O₂ and iodophenol. The resulting luminescence is recorded using a camera luminometer. Urine specimens were available for testing from 31 patients with evidence of ongoing L. pneumophila serogroup 1 infection. A positive result was obtained in the cases of 12/12 specimens from culture-proven LD patients, and 16/19 specimens from patients with serological evidence of LD. Thus the sensitivity is estimated to be 28/31 (90%) The specificity was estimated using urine specimens from eight patients with non-L. pneumophila pneumonias of known aetiology. All eight specimens gave a negative result.