Seven-layer analysis model of an optical waveguide excitation fluorescence microscopy.

In this paper, an optical waveguide evanescent field fluorescence microscopy is studied. Based on Maxwell's equation, a seven-layer theoretical analysis model is developed for the evaluation of an optical waveguide excitation fluorescence microscopy. The optical waveguide excitation fluorescence microscopy structure is systematically and comprehensively analysed at the wavelengths of 488, 532 and 646 nm for fluorescent dyes. The analysis results provide some useful suggestions, which will be beneficial to the research of an optical waveguide evanescent field fluorescence microscopy.

A predictive model of macrosomic birth based upon real-world clinical data from pregnant women.

BACKGROUND: Fetal macrosomia is associated with an increased risk of several maternal and newborn complications. Antenatal predication of fetal macrosomia remains challenging. We aimed to develop a nomogram model for the prediction of macrosomia using real-world clinical data to improve the sensitivity and specificity of macrosomia prediction. METHODS: In the present study, we performed a retrospective, observational study based on 13,403 medical records of pregnant women who delivered singleton infants at a tertiary hospital in Shanghai from 1 January 2018 through 31 December 2019. We split the original dataset into a training set (n = 9382) and a validation set (n = 4021) at a 7:3 ratio to generate and validate our model. The candidate variables, including maternal characteristics, laboratory tests, and sonographic parameters were compared between the two groups. A univariate and multivariate logistic regression was carried out to explore the independent risk factors for macrosomia in pregnant women. Thus, the regression model was adopted to establish a nomogram to predict the risk of macrosomia. Nomogram performance was determined by discrimination and calibration metrics. All the statistical analysis was analyzed using R software. RESULTS: We compared the differences between the macrosomic and non-macrosomic groups within the training set and found 16 independent risk factors for macrosomia (P < 0.05), including biparietal diameter (BPD), head circumference (HC), femur length (FL), amniotic fluid index (AFI) at the last prenatal examination, pre-pregnancy body mass index (BMI), and triglycerides (TG). Values for the areas under the curve (AUC) for the nomogram model were 0.917 (95% CI, 0.908-0.927) and 0.910 (95% CI, 0.894-0.927) in the training set and validation set, respectively. The internal and external validation of the nomogram demonstrated favorable calibration as well as discriminatory capability of the model. CONCLUSIONS: Our model has precise discrimination and calibration capabilities, which can help clinical healthcare staff accurately predict macrosomia in pregnant women.

Atomically Dispersed Co to an End-Adsorbing Molecule for Excellent Biomimetically and Prime Sensitively Detecting O2•- Released from Living Cells.

Single-atom catalysis efficiently exposes the catalytic sites to reactant molecules while rendering opportunity to investigate the catalysis mechanisms at atomic levels for scientific insights. Here, for the first time, atomically dispersed Co atoms are synthesized as biomimetic "enzymes" to monitor superoxide anions (O2•-), delivering ultraordinary high sensitivity (710.03 µA·µM-1·cm-2), low detection limit (1.5 nM), and rapid response time (1.2 s), ranking the best among all the reported either bioenzymatic or biomimetic O2•- biosensors. The sensor is further successfully employed to real-time monitor O2•- released from living cells. Moreover, theoretical calculation and analysis associated with experimental results discover that a mode of end adsorption of the negatively charged O2•- on the Co3+ atom rather than a bridge or/and side adsorption of the two atoms of O2•- on two Co3+ atoms, respectively, plays an important role in the single-atomic catalysis toward O2•- oxidation, which not only facilitates faster electron transfer but also offers better selectivity. This work holds great promise for an inexpensive and sensitive atomic biomimetic O2•- sensor for bioresearch and clinic diagnosis, while revealing that the adsorption mode plays a critical role in single-atom catalysis for a fundamental insight.

[Ecological stoichiometric characteristics of soil and microbial biomass C, N, P in rhizosphere soil of Paris polyphylla and Panax japonicus cultivated understory].

Comparison of total organic carbon(TOC), total nitrogen(TN), total phosphorus(TP), soil microbial biomass carbon(MBC), nitrogen(MBN), phosphorus(MBP) and their stoichiometric ratios measuring from understory planting of Paris polyphylla and Panax japonicus rhizosphere soil with the data of the original forest soil will help us to understand the influence of different planting patterns between soil traits and soil microbial interaction and nutrient cycle characteristics. The results showed that the contents of TOC, TN and MBN were the highest in the rhizosphere soil of P. japonicus, while the highest values of TP, MBC and MBP were found in the rhizosphere soil of P. polyphylla. The changes of TOC∶TN, TOC∶TP, TN∶TP, MBC∶MBN, MBC∶MBP and MBN∶MBP of P. polyphylla and P. japonicus rhizosphere soil compared with the data of the original forest soil were 3.65 and 37.32%,-14.89 and 82.23%,-17.87 and 32.76%, 25.67 and-50.60%,-75.95 and-16.33% as well as-80.79 and 69.76%, respectively. TN and TP were significantly correlated with MBN and MBP respectively. Although, monoculture of P. polyphylla and P. japonicus changed soil nutrient level, it did not reach the state of nutrient deficiency. The demands for nitrogen and phosphorus between P. polyphylla and P. japonicus were quite different. According to their different habits, monoculture of P. polyphylla and P. japonicus could change the understory soil traits, resulting in allometric changes in part of soil nutrient stoichiometry and soil microbial stoichiometry, and then the disappearance of internal stability. The variations in the understory soil caused by P. polyphylla and P. japonicus is developing in completely different directions, whether this phenomenon indicates that the two species have less niche overlap needs further study.

INSULIN RESISTANCE AND POLYCYSTIC OVARY SYNDROME IN A CHINESE POPULATION.

OBJECTIVE: Our study aimed to investigate glucose and lipid level as well as insulin resistance (IR) in patients with polycystic ovary syndrome (PCOS). METHODS: In a case-control study, 426 patients with PCOS were diagnosed according to Rotterdam criteria, and they were conducted in the morning after a 10-h fast. Participants received standard 75-g oral glucose tolerance test (OGTT). Plasma glucose and insulin levels were obtained at 0, 30, 60, 120, and 180 min. They also received the lipid evaluation; 95 healthy women with normal menstrual cycles served as controls. Thus, by modifying the homeostasis model assessment of insulin resistance (HOMA-IR) with the use of individual time-course values of glucose and insulin plasma levels, we developed a new assessment method, HOMA-Mx. RESULTS: In our study, 23.71% of patients had abnormal glucose metabolism. With further impairment in glucose metabolism, the glucose and lipid level gradually increased (P<0.05), while the impaired glucose regulation (IGR) group showed greater insulin response than a type 2 diabetes mellitus (T2DM) group. Compared with healthy controls, both lean and obese PCOS patients with normal glucose tolerance (NGT) had a higher body mass index (BMI), and higher serum glucose, insulin, and lipid values. Additionally, the insulin value peaked at 30 min and 60 min in the lean and obese groups, respectively. HOMA-M30 proved to be the best predictive parameter (cutoff: 20.36, area under the curve [AUC]: 0.753) for assessment of IR in normal-weight patients and HOMA-IR (cutoff: 32.17, AUC: 0.868) was optimal in obese PCOS patients. CONCLUSIONS: A new assessment method was developed for these groups: HOMA-M30 for lean PCOS patients and HOMA-M60 for obese patients, in order to focus on peak insulin values for early detection of IR.

Linear-in-wavenumber swept laser with an acousto-optic deflector for optical coherence tomography.

We report a novel linear-in-wavenumber (k-linear) swept laser source based on an acousto-optic deflector (AOD). The AOD-based optical filter includes an acousto-optic deflector and a reflection grating. The laser may tune k linearly in wavenumber over time due to its appropriate configuration and is favorable for fast imaging because it avoids data resampling and recalibration, as are required in conventional swept source optical coherence tomography (SS-OCT). We achieved k-linearity with Pearson's r correlation coefficients of 0.99995 without and 0.99997 with optimization. The laser has a tuning range of 50 nm, a 3 dB swept range of 42 nm (FWHM), output power of 2.56 mW, 6 dB sensitivity roll-off depth of 0.941 mm, and central wavelength of 1064 nm at a scanning rate of ∼20 kHz. Scanning rate as high as ∼400 kHz is also achieved for this laser with the tuning range 49 nm, swept linearity of 0.99990, output power of 2.30 mW, and a 6 dB sensitivity roll-off depth 0.550 mm. SS-OCT imaging with linear-in-wavenumber swept laser is also demonstrated.

Differential metabolite analysis of the pharmacodynamic differences between different ratios of Dahuang ()-Taoren () herb pair.

OBJECTIVE: To explore the material basis of the difference of efficacy of Dahuang (Radix Et Rhizoma Rhei Palmati)-Taoren (Semen Persicae) (DT) drugs with different proportions. METHODS: Samples of different ratios of Dahuang (Radix et Rhizoma Rhei Palnati, DH) to Taoren (Semen Persicae, TR) (Group A 1:1, B 2:3, C 3:2) were analyzed based on gas chromatography time-of-flight mass spectrometry untargeted metabolomics technique. RESULTS: A total of 240 primary metabolites were detected. Forty-one differential metabolites involved nine differential metabolic pathways, of which four were closely related to the efficacy of DT in the treatment of heat and blood stasis syndrome. These pathways included the biosynthesis of amino acid (phenylalanine tyrosine and tryptophan), flavonoids, unsaturated fatty acids, and the glycolysis/glycogenesis pathway. CONCLUSION: There are significant differences in the efficacy of different ratios of DT drugs, and their optimal ratio for the treatment of heat and blood stasis syndrome should be 1:1.

Co-expression of soluble guanylyl cyclase subunits and PDE5A shRNA to elevate cellular cGMP level: A potential gene therapy for myocardial cell death.

BACKGROUND: Genetic manipulation on the NO-sGC-cGMP pathway has been rarely achieved, partially due to complexity of the soluble guanylyl cyclase (sGC) enzyme. OBJECTIVE: We aim to develop gene therapy directly targeting the pathway to circumvent cytotoxicity and tolerance after prolonged use of NO-donors and the insufficiency of PDE inhibitors. METHODS: In this study, we constructed lentivirus vectors expressing GUCY1A3 and GUCY1B3 genes, which encoded the α1 and ß1 subunits of soluble guanylyl cyclase (sGC), respectively, to enhance cGMP synthesis. We also constructed lentiviral vector harboring PDE5A shRNA to alleviate phosphodiesterase activity and cGMP degradation. RESULTS: Transductions of human HEK293 cells with the constructs were successful, as indicated by the fluorescent signal and altered gene expression produced by each vector. Overexpression of GUCY1A3 and GUCY1B3 resulted in increased sGC enzyme activity and elevated cGMP level in the cells. Expression of PDE5A shRNA resulted in decreased PDE5A expression and elevated cGMP level. Co-transduction of the three lentiviral vectors resulted in a more significant elevation of cGMP in HEK293 cells without obvious cytotoxicity. CONCLUSION: To the best of our knowledge, this is the first study to show that co-expression of exogenous subunits of the soluble guanylyl cyclase could form functional enzyme and increase cellular cGMP level in mammalian cells. Simultaneous expression of PDE5A shRNA could alleviate feedback up-regulation on PDE5A caused by cGMP elevation. Further studies are required to evaluate the effects of these constructs in vivo.

Compressed sensing with linear-in-wavenumber sampling in spectral-domain optical coherence tomography.

We propose a novel method called compressed sensing with linear-in-wavenumber sampling (k-linear CS) to retrieve an image for spectral-domain optical coherence tomography (SD-OCT). An array of points that is evenly spaced in wavenumber domain is sampled from an original interferogram by a preset k-linear mask. Then the compressed sensing based on l1 norm minimization is applied on these points to reconstruct an A-scan data. To get an OCT image, this method uses less than 20% of the total data as required in the typical process and gets rid of the spectral calibration with numerical interpolation in traditional CS-OCT. Therefore k-linear CS is favorable for high speed imaging. It is demonstrated that the k-linear CS has the same axial resolution performance with ~30 dB higher signal-to-noise ratio (SNR) as compared with the numerical interpolation. Imaging of bio-tissue by SD-OCT with k-linear CS is also demonstrated.

Oral epidemic diseases of exposure personnel in long-term low dose radiation.

Oral epidemic diseases of exposure personnel in long-term low-dose radiation yet have rarely been studied. Referred to WHO oral health survey method and symptom grading standard, data of 341 exposure persons in long-term low-dose radiation including α particle, ß particle, and γ rays, etc., were collected from one camp in China in 2011 with cluster sampling and analyzed? with Foxpro 6.0 and SPSS 16.0 software. The exposure persons worked in low-dose radiation for a long time aged between 23 and 56, whose average age were 27.1 years old.In addition, their lengths of service were from 2 to 34 years (average 7.9 years) and average exposure time was 8 hours a day each year for more than three months. Average annual radiation dose equivalent was from 1.8 to 16.5 mSv (average 7.3 mSv). Total radiation dose equivalent was from 3.8 to 425.0 mSv (average 97.3 mSv).

GSH-responsive poly-resveratrol based nanoparticles for effective drug delivery and reversing multidrug resistance.

Cancer poses a serious threat to human health and is the most common cause of human death. Polymer-based nanomedicines are presently used to enhance the treatment effectiveness and decrease the systemic toxicity of chemotherapeutic agents. However, the disadvantage of currently polymeric carriers is without therapy procedure. Herein, for the first time, glutathione (GSH)-responsive polymer (PRES) with anti-cancer effect was synthesized following the condensation-polymerization method using resveratrol (RES) and 3,3'-dithiodipropionic acid. PRES can not only suppress the tumor cells growth but can also self-assemble into nanoparticles (∼93 nm) for delivering antitumor drugs, such as paclitaxel (PTX@PRES NPs). The system could achieve high drug loading (∼7%) and overcome multidrug resistance (MDR). The results from the in vitro studies revealed that the NPs formed of PRES were stable in the systemic circulation, while could be efficiently degraded in tumor cells high GSH environment. Results from cytotoxicity tests confirmed that PTX@PRES NPs could effectively suppress the growth of cancer cells (A549) and drug-resistant cells (A549/PTX). The NPs could also be used to significantly increase the therapeutic efficacy of the drugs in A549/PTX tumor-bearing mice. In vivo investigations also demonstrated that the PRES-based NPs exhibited tumor inhibition effects. In summary, we report that the GSH-responsive polymer synthesized by us exhibited multiple interesting functions and could be used for effective drug delivery. The polymer exhibited good therapeutic effects and could be used to overcome MDR. Thus, the synthesized system can be used to develop a new strategy for treating cancer.

Identification and management of vulval problems of the postmenopausal woman - Tips and tricks.

Vulval irritation and discomfort can be a common presentation to both primary and secondary care. These symptoms can become increasingly prevalent due to physiological changes, which occur to the female genitalia following menopausal transition or due to inflammatory conditions. The correct diagnosis and management can have a huge impact on the patients' quality of life. However, due to the nature of the symptoms, there can be delayed presentation to healthcare professionals. This article gives an overview of the most common benign vulval conditions in the post-menopausal woman, their clinical features and the diagnosis and initial management.

Protective effects of tetramethylpyrazine analogue Z-11 on cerebral ischemia reperfusion injury.

The aim of our study was to investigate the effects of a new synthetic compound (E) -1- (E) -1- (2- hydroxy -5- chlorophenyl) -3- (3, 5, 6- three methyl pyrazine -2- based) -2- propylene -1 ketone, Z-11, a tetramethylpyrazine analogue, on cerebral ischemia reperfusion injury and the underlying mechanism. 240-260 g adult male Wistar rats were subjected to middle cerebral artery occlusion for 2 h, followed by 22 h of reperfusion. Z-11 (1.7, 3.4 and 6.8 mg/kg, i.p.), Edaravone (3 mg/kg, i.p.) and DMSO (1‰, i.p.) was administered at 2 h after the onset of ischemia. The rats' neurological score, infarct volume, and body weight change were tested, and some oxidative stress markers such as superoxide dismutase (SOD) activity, glutathione (GSH) and malondialdehyde (MDA) contents were evaluated after 22 h of reperfusion. Results showed that neurologic deficit, infarct volume and body weight change were ameliorated after cerebral ischemia reperfusion, and that Z-11 exhibits an excellent effect at a dosage of 6.8 mg/kg. This dose also reduced the content of MDA, and upregulated SOD activity and GSH content. Similarly, 6.8 mg/kg Z-11 treatment inhibited the reactive oxygen species content and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, with the protein levels of Ras-related C3 botulinum toxin substrate1(Rac-1) and mitogenic oxidase (Nox2) downregulated even further. Moreover, the protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream anti-oxidant protein heme oxygenase-1 (HO-1) were upregulated. This indicates that Z-11 could play a protective role in cerebral ischemia-reperfusion injury, and that the protective effect of Z-11 may be related to improvements in the antioxidant capacity of brain tissue. The mechanisms are associated with enhancing oxidant defence systems via the activation of Nrf2/HO-1 and Rac-1/NADPH oxidase pathways.

Myricetin nanoliposomes induced SIRT3-mediated glycolytic metabolism leading to glioblastoma cell death.

As the most aggressive and malignant glioma, glioblastoma multiforme (GBM) abnormally expresses genes that mediate glycolytic metabolism and tumour cell growth. In this study, we investigated myricetin incorporated nanoliposomes and ascertained their prospect in effectively treating cancer via the employment of the GBM cell line DBTRG-05MG. Notably, the myricetin nanoliposomes (MYR-NLs) displayed potent inhibition of proliferation and significantly regulated the levels of proteins related to both glycolytic metabolism and cell survival. Most importantly, SIRT3 and phosphorylated p53 were also down-regulated by MYR-NLs, indicating that the MYR-NLs inhibited GBM cell growth through the SIRT3/p53-mediated PI3K/Akt-ERK and mitochondrial pathways. Our findings thus provide rational evidence that liposomal myricetin targeted at alternative cell death pathways may be a useful adjuvant therapy in glioblastoma treatment.

The inhibitory effect of alendronate, a nitrogen-containing bisphosphonate on the PI3K-Akt-NFkappaB pathway in osteosarcoma cells.

1 Bisphosphonates are inhibitors of tumor cell growth as well as of bone resorption by inducing cell apoptosis. However, little is known regarding the mechanisms by which the drug induces cell apoptosis. The aim of the present study was to determine the effect of alendronate, one of the nitrogen-containing bisphosphonates on the phoshoinositide 3-kinase (PI3K)-Akt-NFkappaB pathway, the major cell survival pathway. 2 The PI3K-Akt-NFkappaB pathway was activated in the osteosarcoma cell line MG-63 treated with tumor necrosis factor-alpha or insulin. Saos-2 was also used in some experiments. This was assessed by the production of phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P(3)), increased PI3K activity, phosphorylation of Akt at serine 473 and threonine 308, increase in activity of the inhibitor of nuclear factor kappaB (IkappaB) kinase (IKK) and finally phosphorylation of IkappaB and its subsequent degradation. 3 Pretreatment with alendronate at 100 microM for 24 h prior to the stimulation with tumor necrosis factor-alpha or insulin partially inhibited the IkappaB phosphorylation and degradation. These events were more clearly observed in the presence of inhibitors of proteasomes, which are responsible for the degradation of IkappaB. The drug also partially inhibited the activity of IKK, but almost fully inhibited the phosphorylation of Akt and the production of PtdIns(3,4,5)P(3). 4 The inhibitory effect of alendronate on IkappaB phosphorylation and degradation was not attenuated by the exogenous addition of geranylgeraniol to replenish the cytosolic isoprenyl lipid substrate. 5 The present findings demonstrate that alendronate inhibited the PI3K-Akt-NFkappaB cell survival pathway at the point of PI3K activation, thus indicating the presence of new targets of alendronate.

[Comparison between cone beam computed tomography and periapical radiography in the diagnosis of periapical disease].

With the development of medical radiography, cone beam computed tomography (CBCT) has been widely used in stomatology because of its numerous advantages, such as adequate spatial resolution, low radiation, undistorted three- dimensional tissue information, and good applicability for hard tissue imaging. Traditional periapical radiography is based on two-dimensional image which displays the three-dimensional object and its surrounding structures. Periapical radiography can only show the overlapping mesio-distally direction bone destruction, can't show buccolingual direction bone destruction. As a kind of three-dimensional imaging technology, CBCT can show three-dimensional structure of the organization from sagittal, coronal and axial direction, to overcome the defect of two-dimensional image such as overlap and deformation. CBCT has a unique advantage than periapical radiography in the diagnosis and treatment for periapical disease. This review will summarize the difference between CBCT and periapical radiography in the periapical disease.

Mining gene link information for survival pathway hunting.

This study proposes a gene link-based method for survival time-related pathway hunting. In this method, the authors incorporate gene link information to estimate how a pathway is associated with cancer patient's survival time. Specifically, a gene link-based Cox proportional hazard model (Link-Cox) is established, in which two linked genes are considered together to represent a link variable and the association of the link with survival time is assessed using Cox proportional hazard model. On the basis of the Link-Cox model, the authors formulate a new statistic for measuring the association of a pathway with survival time of cancer patients, referred to as pathway survival score (PSS), by summarising survival significance over all the gene links in the pathway, and devise a permutation test to test the significance of an observed PSS. To evaluate the proposed method, the authors applied it to simulation data and two publicly available real-world gene expression data sets. Extensive comparisons with previous methods show the effectiveness and efficiency of the proposed method for survival pathway hunting.

Association of follicle stimulating hormone receptor promoter with ovarian response in IVF-ET patients.

BACKGROUND: Poor ovarian response phenomenon has been observed in some of the in vitro fertilization-embryo transfer patients. Some investigations found that follicle stimulating hormone receptor ( FSHR ) gene plays a role in the process, but no direct evidence shows the correlation between genotypes of FSHR and ovarian response. OBJECTIVE: Exploring the molecular mechanism behind the mutation of FSH R promoter association with ovarian granulosa cells and poor ovarian response. MATERIALS AND METHODS: This cross sectional study was performed using 158 women undergoing the controlled short program ovarian stimulation for IVF treatment. The 263 bp DNA fragments before the follicle stimulating hormone (FSH) receptor 5' initiation site were sequenced in the patients under IVF cycle, 70 of which had poor ovarian response and 88 showed normal ovarian responses. RESULTS: With a mutation rate of 40%, 63 in 158 cases showed a 29(th) site G→A point mutation; among the mutated cases, the mutation rate of the poor ovarian responders was significantly higher than the normal group (60% versus 23.9%; χ2=21.450, p<0.001). Besides, the variability was also obvious in antral follicle count, and ovum pick-ups. The estradiol peak values and the number of mature eggs between the two groups had significant difference. However, there was no obvious variability (t=0.457, p=0.324) in the basic FSH values between the two groups (normal group, 7.2±2.3 U/L; mutation group, 7.1±2.0 U/L). CONCLUSION: The activity of FSHR promoter is significantly affected by the 29(th) site G→A mutation that will weaken promoter activity and result in poor response to FSH.

Inhibitory effects of angiotensin on NMDA-induced cytotoxicity in primary neuronal cultures.

Primary cultures from the hypothalamus/thalamus/septum/midbrain (HTSM) region of 1-day-old mice were used to investigate the effects of angiotensin on NMDA excitotoxicity. Cell viability was determined following exposure to 1-10 mM glutamate or 0.01-10 mM NMDA. Cells exposed to 1 mM glutamate or 1 mM NMDA for 24 h showed a significant increase in cell death as determined by propidium iodide staining. HTSM cultures treated with 0.1 mM NMDA revealed both DNA laddering and positive staining for TUNEL, suggesting apoptosis as the primary mechanism for the cell death. We also determined whether angiotensin II (Ang II) modulated NMDA-induced cell death in HTSM-cultured neurons. Cells pre-treated with 10 nM Ang II showed a decrease in NMDA-induced cytotoxicity, TUNEL staining and DNA laddering. NMDA-induced cell death was also reduced when cells were pre-treated with the AT1 receptor antagonist losartan. In this study, we have shown that NMDA and glutamate induce cell death through the NMDA receptor, and that Ang II, acting primarily through the AT2 receptor, can attenuate this response.

[Effects of losartan on MT3-MMP and TIMP2 mRNA expressions in diabetic rat kidney].

OBJECTIVE: To investigate the changes of the mRNA expressions of membrane type 3-matrix metalloproteinase (MT3-MMP) and tissue inhibitor of matrix metalloproteinase 2 (TIMP2) in diabetic rat kidneys and the effect of losartan on such changes. METHODS: Three groups of male Wistar rats were used in this study, namely group A as the control group (n=11), group B consisting of diabetic rats without any therapy (n=11), and group C treated with losartan (n=9). Six months after treatment, the kidneys were taken from the rats to measure the mRNA expressions of MT3-MMP, TIMP2 and transforming growth factor beta1eTGFbeta1 with reverse transcriptional PCR (RT-PCR), and observe the glomerular basement membrane thickening and mesangial matrix MMedensity (MM area/mesangial area) with electron microscope. Twenty-four-hour urine was also collected to measure urinary albumin excretion (UAE). RESULTS: The expression of renal MT3-MMP mRNA in group B (1.37+/-0.96) was significantly stronger than those in group A (0.75+/-0.34, P<0.05) and in group C (0.75+/-0.30, P<0.05). The mRNA expression of renal TIMP2 in group B (0.73+/-0.37) was significantly increased as compared with group A (0.32+/-0.19, P<0.05) and group C (0.34+/-0.17, P<0.05), with a higher mRNA expression of renal TGFbeta1 in group B (0.53+/-0.20 vs 0.26+/-0.13 in group A and 0.29+/-0.15 in group C, P<0.05). UAE in group B (2.18+/-1.98 mg) was significantly higher than those in groups A and C (0.41+/-0.47 mg/d, P<0.05; 0.65+/-0.89 mg/d, P<0.05, respectively). The glomerular basement membrane thickness (532+/-108 nm) and the MM density (56.4+/-6.8) were significantly greater in group Bthan in the other two groups (P<0.05). CONCLUSIONS: MT3-MMP and the TIMP2 mRNA expressions are significantly increased in diabetic rat kidneys. Losartan can prevent the development of diabetic nephropathy and inhibit MT3-MMP and the TIMP2 mRNA expressions in diabetic rat kidneys.