Endothelium-derived relaxing factor/nitric oxide modulates angiotensin II action in the isolated microperfused rabbit afferent but not efferent arteriole

It has been reported that sensitivity to angiotensin II (Ang II) is higher in efferent (Ef) than afferent (Af) arterioles (Arts). We tested the hypothesis that this is due to arteriolar differences in the interaction between Ang II and endothelium-derived relaxing factor/nitric oxide (EDNO). Rabbit Af-Arts with glomerulus intact were microperfused in vitro at a constant pressure. Ef-Arts were perfused from the distal end of either the Af-Art (orthograde perfusion) or the Ef-Art (retrograde perfusion) to eliminate influences of the Af-Art or glomerulus, respectively. Ang II did not alter Af-Art luminal diameter until the concentration reached 10(-9) M, which decreased the diameter by 11 +/- 2.6% (n = 11; P < 0.002). In contrast, Ef-Arts became significantly constricted at concentrations as low as 10(-11) M with either perfusion. Surprisingly, the decrease in Ef-Art diameter at 10(-10), 10(-9), and 10(-8) M was significantly greater with retrograde perfusion (44 +/- 6.9%, 70 +/- 5.6%, and 74 +/- 4.1%, respectively; n = 5) than with orthograde perfusion (16 +/- 4.2%, 25 +/- 2.9%, and 35 +/- 3.5%; n = 9). ENDO synthesis inhibition with 10(-4) M nitro-L-arginine methyl ester (L-NAME) decreased the diameter to a greater extent in Af-Arts (22 +/- 3.0%; n = 11) compared to Ef-Arts with either orthograde (9.5 +/- 2.3%; n = 8) or retrograde perfusion (1.2 +/- 2.1%; n = 6). With L-NAME pretreatment, Af-Art constriction induced by 10(-10) M (14 +/- 4.0%, n = 9) and 10(-9) M Ang II (38 +/- 3.9%) was significantly greater compared to nontreated Af-Arts. In contrast, L-NAME pretreatment had no effect on Ang II-induced constriction in Ef-Arts with either perfusion. In conclusion, this study demonstrates higher sensitivity of Ef-Arts to Ang II, particularly with retrograde perfusion. Our results suggest that EDNO significantly modulates the vasoconstrictor action of Ang II in Af-Arts II but not Ef-Arts, contributing to the differential sensitivity to Ang II.

The beta 4 subunit cytoplasmic domain mediates the interaction of alpha 6 beta 4 integrin with the cytoskeleton of hemidesmosomes

The alpha 6 beta 4 integrin is structurally distinct from all the other known integrins because the cytoplasmic domain of beta 4 is unusually large and contains four type III fibronectin-like modules toward its C-terminus. To examine the function of the beta 4 cytoplasmic tail, we have expressed full-length and truncated human beta 4 cDNAs in rat bladder epithelial 804G cells, which form hemidesmosome-like adhesions in vitro. The cDNA encoded wild-type beta 4 subunit associated with endogenous alpha 6 and was recruited at the cell surface within hemidesmosome-like adhesions. A recombinant form of beta 4, lacking almost the entire cytoplasmic domain associated with alpha 6, reached the cell surface but remained diffusely distributed. A beta 4 molecule lacking almost the entire extracellular portion did not associate with alpha 6 but was correctly targeted to the hemidesmosome-like adhesions. Thus, the cytoplasmic portion of beta 4 contains sequences that are required and may be sufficient for the assembly of the alpha 6 beta 4 integrin into hemidesmosomes. To localize these sequences we examined the properties of additional mutant forms of beta 4. A truncated beta 4 subunit, lacking the most C-terminal pair of type III fibronectin homology domains, was incorporated into hemidesmosome-like adhesions, but another recombinant beta 4 molecule, lacking both pairs of type III fibronectin repeats, was not. Finally a recombinant beta 4 molecule, which was created by adjoining the region of the cytoplasmic domain including all type III repeats to the transmembrane segment, was efficiently recruited in hemidesmosome-like adhesions. Taken together these results suggest that the assembly of the alpha 6 beta 4 integrin into hemidesmosomes is mediated by a 303-amino acid region of beta 4 tail that comprises the first pair of type III fibronectin repeats and the segment between the second and third repeats. These data imply a function of a specific segment of the beta 4 cytoplasmic domain in interaction with cytoskeletal components of hemidesmosomes.

Role of macula densa nitric oxide and cGMP in the regulation of tubuloglomerular feedback

BACKGROUND

Previous studies have suggested that nitric oxide (NO) produced within cells of the macula densa (MD) modulates tubuloglomerular feedback (TGF). We tested the hypothesis that NO produced in the MD acts locally as an autacoid to activate soluble guanylate cyclase and cGMP-dependent protein kinase in the MD itself.

METHODS

Rabbit afferent arterioles (Af-Arts) and attached MD were simultaneously microperfused in vitro. The TGF response was determined by measuring the Af-Art diameter before and after increasing NaCl in the MD perfusate (from 17 mmol/L of Na and 2 of Cl to 65 mmol/L of Na and 50 of Cl). TGF was studied before (control TGF) and after inhibiting components of the NO-cGMP-dependent cascade in the tubular or vascular compartment.

RESULTS

Increasing NaCl concentration in the MD perfusate decreased the Af-Art diameter by 3.2 +/- 0.5 microm (from 18.5 +/- 1.3 to 15.4 +/- 1.3 microm, P < 0.001). Adding a soluble guanylate cyclase inhibitor (LY83583) to the MD increased TGF response to 6.3 +/- 1.1 microm (P < 0.031 vs. control TGF). Similarly, when cGMP-dependent protein kinase was inhibited with KT5823, TGF was augmented from 2.6 +/- 0.3 to 4.0 +/- 0.7 microm (P < 0.023). An analogue of cGMP in the MD reversed the TGF-potentiating effect of both 7-nitroindazole (7NI; an nNOS inhibitor) and LY83583. Inhibition of MD guanylate cyclase did not alter the effect of acetylcholine (a NO-cGMP-dependent vasodilator) on the Af-Art. Perfusing the Af-Art with the guanylate cyclase inhibitor did not potentiate TGF, suggesting that the effect of NO occurred at the MD via a cGMP-dependent mechanism. To determine whether the effect of NO in the MD was entirely mediated by cGMP, TGF was studied after giving (1) LY83583 or (2) LY83583 plus 7NI. Adding the nNOS inhibitor to the MD did not potentiate the TGF response further.

CONCLUSIONS

We concluded the following: (1) NO produced by the MD inhibits TGF via stimulation of soluble guanylate cyclase, generating cGMP and activating cGMP-dependent protein kinase; (2) NO acts on the MD itself rather than by diffusing to the Af-Art; and (3) most, if not all, of the effect of NO in the MD is due to a cGMP-dependent mechanism rather than to other NO mediators.

Cooperative DNA binding of heterologous proteins: evidence for contact between the cyclic AMP receptor protein and RNA polymerase

Four cAMP-independent receptor protein mutants (designated CRP* mutants) isolated previously are able to activate in vivo gene transcription in the absence of cAMP and their activity can be enhanced by cAMP or cGMP. One of the four mutant proteins, CRP*598 (Arg-142 to His, Ala-144 to Thr), has been characterized with regard to its conformational properties and ability to bind to and support abortive initiation from the lac promoter. In the absence of cGMP, CRP*598 shows a more open conformation than CRP, as indicated by its sensitivity to proteolytic attack and 5,5'-dithiobis(2-nitrobenzoic acid)-mediated subunit crosslinking. Binding of wild-type CRP to its site on the lac promoter and activation of abortive initiation by RNA polymerase on this promoter are effected by cAMP but not by cGMP. CRP*598 can activate lacP+-directed abortive initiation in the presence of cAMP and less efficiently in the presence of cGMP or in the absence of cyclic nucleotide. DNase I protection ("foot-printing") indicates that cAMP-CRP* binds to its site on the lac promoter whereas unliganded CRP* and cGMP-CRP* form a stable complex with the [32P]lacP+ fragment only in the presence of RNA polymerase, showing cooperative binding of two heterologous proteins. This cooperative binding provides strong evidence for a contact between CRP and RNA polymerase for activation of transcription. Although cGMP binds to CRP, it cannot replace cAMP in effecting the requisite conformational transition necessary for site-specific promoter binding. In contrast, the weakly active unliganded CRP*598 can be shifted to a functional state not only by cAMP but also by cGMP and RNA polymerase.

Aerobic degradation of tetrabromobisphenol-A by microbes in river sediment

This study investigated the aerobic degradation of tetrabromobisphenol-A (TBBPA) and changes in the microbial community in river sediment from southern Taiwan. Aerobic degradation rate constants (k(1)) and half-lives (t(1/2)) for TBBPA (50 μg g(-1)) ranged from 0.053 to 0.077 d(-1) and 9.0 to 13.1 d, respectively. The degradation of TBBPA (50 μg g(-1)) was enhanced by adding yeast extract (5 mg L(-1)), sodium chloride (10 ppt), cellulose (0.96 mg L(-1)), humic acid (0.5 g L(-1)), brij 30 (55 μM), brij 35 (91 μM), rhamnolipid (130 mg L(-1)), or surfactin (43 mg L(-1)), with rhamnolipid yielding a higher TBBPA degradation than the other additives. For different toxic chemicals in the sediment, the results showed the high-to-low order of degradation rates were bisphenol-A (BPA) (50 μg g(-1))>nonylphenol (NP) (50 μg g(-1))>4,4'-dibrominated diphenyl ether (BDE-15) (50 μg g(-1))>TBBPA (50 μg g(-1))>2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) (50 μg g(-1)). The addition of various treatments changed the microbial community in river sediments. The results also showed that Bacillus pumilus and Rhodococcus ruber were the dominant bacteria in the process of TBBPA degradation in the river sediments.

Role of neuronal nitric oxide synthase in the macula densa

BACKGROUND

There is evidence that macula densa nitric oxide (NO) inhibits tubuloglomerular feedback (TGF). However, TGF response is not altered in mice deficient in neuronal nitric oxide synthase (nNOS) (-/-). Furthermore, nNOS expression in the macula densa is inversely related to salt intake, yet micropuncture studies have shown that NOS inhibition potentiates TGF in rats on high sodium intake but not in rats on a low-salt diet. These inconsistencies may be due to confounding systemic factors, such as changes in circulating renin. To further clarify the role of macula densa nNOS in TGF response, independent of systemic factors, we tested the hypothesis that (1) TGF response is inversely related to sodium intake, and (2) during low sodium intake, NO produced by macula densa nNOS tonically controls the basal diameter of the afferent arteriole (Af-Art).

METHODS

Af-Arts and attached macula densas were simultaneously microperfused in vitro. TGF response was determined by measuring Af-Art diameter before and after increasing NaCl in the macula densa perfusate. TGF response was studied in wild-type (+/+) and nNOS knockout mice (-/-), as well as in juxtaglomerular apparatuses (JGAs) from rabbits fed a low-, normal-, or high-NaCl diet.

RESULTS

TGF responses were similar in nNOS +/+ and -/- mice. However, in nNOS +/+ mice, 7-nitroindazole (7-NI) perfused into the macula densa significantly potentiated the TGF response (P = 0.001), while in nNOS -/- mice, this potentiation was absent. In rabbits on three different sodium diets, TGF responses were similar and were potentiated equally by 7-NI. However, in JGAs from rabbits on a low-NaCl diet, adding 7-NI to the macula densa while perfusing it with low-NaCl fluid caused Af-Art vasoconstriction, decreasing the diameter by 14% (from 21.7 +/- 1.3 to 18.6 +/- 1.5 microm; P < 0.001). This effect was not observed in JGAs from rabbits fed a normal- (19.0 +/- 0.5 vs. 19.3 +/- 0.8 microm after 7-NI) or high-NaCl diet (18.6 +/- 0.7 vs. 18.4 +/- 0.7 microm).

CONCLUSIONS

First, in this in vitro preparation, chronic changes in macula densa nNOS do not play a major role in the regulation of TGF. Compensatory mechanisms may develop during chronic alteration of nNOS that keep TGF relatively constant. Second, nNOS regulates TGF response acutely. Third, the results obtained in the +/+ and -/- mice also confirm that the effect of 7-NI is due to inhibition of macula densa nNOS. Finally, during low sodium intake (without induction of TGF), the regulation of basal Af-Art resistance by macula densa nNOS suggests that NO in the macula densa helps maintain renal blood flow during the high renin secretion caused by low sodium intake.

Micrometastases detected by cytokeratin 19 expression in sentinel lymph nodes of patients with early-stage cervical cancer

The purpose of this study was to detect micrometastases in sentinel lymph nodes (SLNs) by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) analyses for cytokeratin 19 (CK19) expression in early-stage cervical cancer. One hundred twenty-five SLNs were collected from 46 patients with early-stage cervical cancer. Conventional histopathologic techniques revealed 14 metastatic SLNs from 11 out of 46 patients. CK19 expression was detected by RT-PCR and IHC in all the 125 SLNs. Cervical cancer tissues from nine patients and five pelvic lymph nodes from the patients without tumor were utilized as positive and negative controls, respectively. All the metastastic SLNs on conventional histopathologic techniques were positive by either RT-PCR or IHC analyses, while all the positive controls were positive and all the negative controls were negative as expected. Of 35 patients without metastatic SLNs on conventional histopathologic techniques, the detection rate of micrometastases was 42.85% by RT-PCR and 20% by IHC analyses. RT-PCR and IHC were more sensitive to identify micrometastases in SLNs of patients with early-stage cervical cancer than routine pathology. These findings demonstrated that micrometastasis could be identified by molecular technique such as RT-PCR and IHC analyses for CK19 expression. RT-PCR was more sensitive to detect micrometastases in SLNs than IHC in patients with early-stage cervical cancer. Therefore, molecular assessment of the SLNs may be a valuable tool to complement routine histologic examination of cervical cancer. The importance of micrometastases in SLNs is under close clinical observation to determine whether it can be used as a predicting factor to help us make decision whether to proceed with whole-pelvic lymph node dissection or as a prognostic factor for clinical outcome.

Vasodilator and constrictor actions of platelet-activating factor in the isolated microperfused afferent arteriole of the rabbit kidney. Role of endothelium-derived relaxing factor/nitric oxide and cyclooxygenase products

It has been suggested that platelet-activating factor (PAF) plays a prominent role in the control of glomerular hemodynamics in various physiological and pathological conditions. We examined the direct effect of PAF on rabbit glomerular afferent arterioles (Af-Arts) microperfused in vitro and tested whether endothelium-derived relaxing factor/nitric oxide (EDNO) and cyclooxygenase products are involved in its actions. In nanomolar concentrations PAF caused dose-dependent constriction of Af-Arts, with the maximum constriction being 34 +/- 10% at 4 x 10(-8) M (n = 9, P < 0.001). The constriction was blunted by cyclooxygenase inhibition (11 +/- 6%, n = 7, P < 0.05) but augmented by EDNO inhibition (76 +/- 14%, n = 8, P < 0.005). To study a possible vasodilator effect of PAF, Af-Arts were preconstricted with norepinephrine and increasing concentrations of PAF added to the lumen. At picomolar concentrations (lower than those that caused constriction), PAF produced dose-dependent vasodilation that was unaffected by cyclooxygenase inhibition but was abolished by EDNO synthesis inhibition. Both PAF-induced constriction and dilation of Af-Arts were blocked by a PAF receptor antagonist. This study demonstrates that PAF has a receptor-mediated biphasic effect on rabbit Af-Arts, dilating them at low concentrations while constricting them at higher concentrations. Our results suggest that PAF's vasodilator action may be due to production of EDNO, while its constrictor action is mediated at least in part through cyclooxygenase products.

Simultaneous determination of two active components in compound aspirin tablets using principal component artificial neural networks (PC-ANNs) on NIR spectroscopy

A method for simultaneous, non-destructive analysis of aspirin and phenacetin in compound aspirin tablets with different concentrations has been developed by principal component artificial neural networks (PC-ANNs) on near-infrared (NIR) spectroscopy. In PC-ANNs models, the spectra data were first analyzed by principal component analysis (PCA). Then the scores of the principal compounds (PCs) were chosen as input nodes for input layer instead of the spectra data. The artificial neural networks (ANNs) models using the spectra data as input nodes were also established, which were compared with the PC-ANNs models. Four different preprocessing methods (first-derivation, second-derivation, standard normal variate (SNV) and multiplicative scatter correction (MSC)) were applied to NIR conventional spectra. The result shows the first-derivative model of PC-ANNs multivariate calibration has the lowest training errors and predicting errors. The concept of the degree of approximation was introduced and performed as the selective criterion of the optimum network parameters.

Influence of NaCl concentration at the macula densa on angiotensin II-induced constriction of the afferent arteriole

The macula densa, a plaque of specialized tubular epithelial cells, monitors NaCl concentrations in tubular fluid and controls resistance of the glomerular afferent arteriole (AA). In vivo micropuncture studies suggest that there are significant interactions between angiotensin II (Ang II) and macula densa control of glomerular hemodynamics. We tested the hypothesis that Ang II causes stronger constriction of the AA when NaCl concentration at the macula densa is elevated. Rabbit AAs and the attached macula densa were simultaneously microperfused in vitro, and dose-response curves to Ang II were obtained when the macula densa was not perfused or was perfused with either low NaCl (Na+, 26 mEq/L; Cl-, 7 mEq/L) or high NaCl (Na+, 84 mEq/L; Cl-, 65 mEq/L). Ang II induced stronger constriction when the macula densa was perfused with high NaCl; the decrease in diameter at 100 pmol/L was 29 +/- 5.6% (n= 7) compared with 2.1 +/- 1.2% (n=8) for the nonperfused macula densa or 6.1 +/- 4.2% (n=7) for low NaCl (P < .002). However, there was no such difference in the action of norepinephrine. Adding furosemide (10 micromol/L) to the macula densa perfusate abolished the difference in Ang II action between low and high NaCl at the macula densa. Since AA tone is higher when the NaCl concentration at the macula densa is elevated, we tested whether augmented Ang II action is due to higher AA tone. Preconstriction of the AA by 20% with norepinephrine had no effect on Ang II action. Thus, our results demonstrate that sensitivity of the AA to Ang II increases when NaCl concentration at the macula densa is elevated. Such modulation of Ang II action by macula densa NaCl concentration may be important in the control of glomerular hemodynamics.

Characterization of the binding of cAMP and cGMP to the CRP*598 mutant of the E. coli cAMP receptor protein

Wild type cAMP receptor protein (CRP) activates in vitro lac transcription only in the presence of cAMP. In contrast the mutant CRP*598 (Arg-142 to His, Ala-144 to Thr) can activate lac transcription in the absence of cyclic nucleotide or at concentrations of cAMP below that required by CRP. To further characterize the properties of CRP*598, the binding of cAMP and cGMP to CRP and CRP*598 has been determined. The intrinsic binding constant (K) values obtained for cAMP binding are: CRP, 1.9 x 10(4) M-1; CRP*598, 3.8 x 10(5) M-1. The K values obtained for cGMP binding are: CRP, 2.9 x 10(4) M-1; CRP*598, 2.7 x 10(4) M-1. The results indicate that the affinity of CRP and CRP*598 for cGMP is relatively unchanged while the affinity of CRP*598 for cAMP is approximately twenty times greater than that shown by CRP. Binding of cAMP by CRP and cGMP by CRP or CRP*598 exhibits slight negative cooperativity. The major difference seen is that CRP*598 binds cAMP with strong positive cooperativity. The importance of the unsubstituted N6 position of the adenine moiety is also shown by the similar affinity of both forms of CRP for N6-butyryl cAMP. The cAMP binding properties evinced by CRP*598 suggest that its intrinsically altered conformation may be related to that assumed by CRP in a CRP-DNA or a cAMP-CRP-DNA complex.

Methods of developing core collections based on the predicted genotypic value of rice ( Oryza sativa L.)

The selection of an appropriate sampling strategy and a clustering method is important in the construction of core collections based on predicted genotypic values in order to retain the greatest degree of genetic diversity of the initial collection. In this study, methods of developing rice core collections were evaluated based on the predicted genotypic values for 992 rice varieties with 13 quantitative traits. The genotypic values of the traits were predicted by the adjusted unbiased prediction (AUP) method. Based on the predicted genotypic values, Mahalanobis distances were calculated and employed to measure the genetic similarities among the rice varieties. Six hierarchical clustering methods, including the single linkage, median linkage, centroid, unweighted pair-group average, weighted pair-group average and flexible-beta methods, were combined with random, preferred and deviation sampling to develop 18 core collections of rice germplasm. The results show that the deviation sampling strategy in combination with the unweighted pair-group average method of hierarchical clustering retains the greatest degree of genetic diversities of the initial collection. The core collections sampled using predicted genotypic values had more genetic diversity than those based on phenotypic values.

Ultra-long high quality catalyst-free WO3 nanowires for fabricating high-performance visible photodetectors

This work presents a study on the controlled growth of WO₃ nanowires via chemical vapor deposition without catalyst, and their potential applications in visible photodetectors. The influence of growth conditions on the morphology of WO₃ nanowires is studied in order to understand the growth mechanism of WO₃ nanowires, and ultra-long (60 [Formula: see text], the longest one ever reported) WO₃ nanowires with a spindle shape are achieved by optimizing the growth conditions. It was found that the length of WO₃ nanowires increases from 15 [Formula: see text] to 60 [Formula: see text] with increasing the argon carrier gas flow rate from 30 sccm to 90 sccm, and then saturates with further increasing the argon carrier gas flow rate. However, the length of WO₃ nanowires reduces from 60 [Formula: see text] to 19 [Formula: see text] with increasing the tube inner pressure from 2.5 Torr to 3.5 Torr. The photoconductor detectors based on WO₃ single nanowires present excellent device performance with a responsivity as high as 19 A W^-1 at a bias of 0.1 V, a detectivity as high as 1.06 × 10¹¹ Jones, and a response (rising and decay) time as short as 8 ms under the illumination of a 404 nm laser. These results indicate the great potential of WO₃ nanowires for applications in fabricating high performance visible photodetectors.

Comparison of solvent extraction and microwave extraction for release of dimethyl sulfide from cereals and canola

Natural levels of dimethyl sulfide (DMS) in newly harvested wheat, barley, paddy, and canola were determined by gas chromatography using a flame photometric detector in sulfur mode. The two methods involved determination of DMS in the headspace of cereal or oilseed samples (1) after extraction with microwaves and (2) after a traditional approach using 25% KBr solution. Quantitative results from each method were similar, and therefore both methods are suitable for the determination of DMS in grains and oilseeds. However, the microwave procedure has several advantages; for example, results are obtained very quickly, and only a small amount of sample is required.

Fate of (14)C-labeled carbonyl sulfide on grains and grain fractions

14C-Labeled carbonyl sulfide (COS) was used to measure the amount of sorbed fumigant and alteration products on grains. Wheat, paddy rice, polished rice, mungbean, and safflower were exposed to a 60 mg L(-)(1) of (14)COS for 7 days and then aired for 5 days. Carbonyl sulfide and/or alteration products in sugars, protein, starch, amino acids, protopectines, and hemicelluloses were undetectable. The total uptakes of radioactivity determined after fractionation and also by extraction were in the range of 36-53 ng g(-)(1) COS equiv. The total radioactivity determined by autoradiography was below the detection limit of 70 ng g(-)(1) COS equiv. Radioactivity in the commodities was less than 0.003% of all the radioactivity applied. The amount of retained radiolabel was measured in three ways. First, biochemical fractions such as lipids and amino acids were separated by chromatography, and the activity was determined in each component. Second, commodities were crushed and extracted in aqueous acetone until the maximum amount of radiolabel was extracted. Third, autoradiography was carried out on commodity kernels.

Natural levels of dimethyl sulfide in rough rice and its products

Natural levels of dimethyl sulfide (DMS) in rough rice and its products (polished rice, brown rice, and broken rice) were determined by a gas chromatograph equipped with a flame photometric detector and sulfur mode, after extraction with 25% KBr solution in a sealed system. DMS was found to occur naturally in nine newly harvested and stored Australian varieties of rough rice and its products and decreased during storage after harvesting. Natural levels of DMS in rough rice and its products varied with variety, fraction, and period of storage. The order of levels of DMS was rough rice = brown rice > polished rice = broken rice. The range of values was 0.002-30 mg kg(-1) (ppm, w/w).

[A preliminary study on the outcome of lower-risk myelodysplastic syndrome by low-dose decitabine]

目的

评价小剂量地西他滨治疗较低危骨髓增生异常综合征（MDS）患者的初步疗效及安全性，探讨MDS相关基因突变的临床意义。

方法

纳入浙江省4所医院收治的62例较低危MDS患者，治疗分2组，地西他滨组（地西他滨12 mg·m⁻²·d⁻¹，连续5 d）和支持治疗组，检测与MDS预后相关的15项基因突变情况。比较两组患者的总体有效率（ORR）和无进展生存（PFS）时间，分析其与基因突变的相关性。

结果

62例患者中，可评估患者51例，其中地西他滨组24例，支持治疗组27例。与支持治疗组相比，地西他滨组的ORR（66.7%对29.6%，χ²=6.996，P=0.008）和中位PFS时间显著改善（未达到对13.7个月，P=0.037）。51例患者中20例（39.2%）检测到基因突变阳性，其中4例患者单纯SF3B1阳性，均在支持治疗组。与基因突变阴性患者相比，16例基因突变阳性（除单纯SF3B1阳性）患者中位PFS时间显著缩短（9.2个月对18.5个月，P=0.008），其中地西他滨组8例患者中6例有效，支持治疗组无一例（0/8）有效。地西他滨治疗期间主要不良反应为3~4级粒细胞减少（45.8%），3~4级感染发生率为33.3%（8/24）。

结论

该研究小系列患者的初步结果表明应用小剂量地西他滨治疗较低危MDS患者可能有效，对于基因突变患者也可获益，且患者耐受，值得临床试验进一步明确其临床意义。

[Clinical analysis of lower limb thrombosis caused by paraquat poisoning]

Objective: To investigate the causes of peripheral vascular thrombosis in patients with paraquat poisoning. Methods: The patients with paraquat poisoning who were admitted to our department in recent two years were observed to screen out the patients with large vessel thrombosis. The data on toxic exposure history, clinical features, and treatment were collected to analyze the causes of thrombosis in the patients with paraquat poisoning. Results: Three patients had typical lower limb thrombosis. There was one case of right common femoral vein thrombosis, one case of bilateral calf muscle vein thrombosis, and one case of right calf superficial vein thrombosis and right calf muscle vein thrombosis. Conclusions: After paraquat poisoning, the blood is in a hypercoagulable state and prolonged bed rest may increase the risk of thrombosis.

[Clinical phenotype and genetic analysis of patients with left ventricular noncompaction caused by the biallelic mutation of MYBPC3 and MYH7]

Objective: To explore the relationship between pathogenic gene, mutation and phenotype of left ventricular noncompaction (LVNC) patients and their family members. Methods: The subjects were the proband with LVNC and her family members. The medical history including electrocardiogram, echocardiography and cardiac magnetic resonance examination of the proband and family members were collected. Whole exome sequencing of the proband was performed, bioinformatics analysis focused on the genes related to hereditary cardiomyopathy. Candidate pathogenic sites were validated by Sanger sequencing. The clinical interpretation of sequence variants were classified according to American College of Medical Genetics and Genomics (ACMG) guidelines. Results: The proband carried a heterozygous variation of the MYBPC3 gene c.C2827T and the MYH7 gene c.G2221C. The proband's sister carried heterozygous variation of MYBPC3 gene c.C2827T. According to the ACMG guidelines, the variant was determined to be pathogenic. Conclusion: The missense variant of MYBPC3 gene c.C2827T and MYH7 gene c.G2221C are identified from the proband with LVNC and her family member, which provides a genetic basis for clinical diagnosis and genetic counseling of the patients and the family members with LVNC.

[Study on chemical constituents of Hemistepta lyrata Bunge]

AIM

To separate and identify the chemical constituents of the whole plant of Hemistepta lyrata Bunge.

METHODS

Compounds wese separated with chromatography and their chemical strucrures were elucidated with UV, IR, EIMS, FABMS, ESIMS, 1HNMR, 13CNMR HMQC and HMBC spectral methods.

RESULTS

Five compounds were isolated from the plant. They were identified as apigenin I, apigenin-7-O-beta-D-lutinoside II, acacetin-7-O-beta-D-lutinoside III, astragalin IV, hemislienoside V.

CONCLUSION

These compounds were isolated from this plant for the first time, and compound V is a new one.

[Immune interference of enteroviruses to immune response of TOPV in subtroptical areas]

To study whether enteroviruses interfere with the immunoeffect of TOPV in subtroptical areas, a total number of 188 children were investigated 82 in summer, 106 in winter in two townships of Hui Dong County from 1992 to 1993. The carrier rates of enteroviruses and serum nutralization antibody titres of polio were tested before and after the children were vaccinated with TOPV. Data showed that the GMTs of poliovirus type I, II, III in winter were 2 to 7.1 times as much as those in summer after administration of one and three doses TOPV. Enterovirus carrier rates were 75.6% and 38.8% respectively in summer and winter before vaccination in health children. The GMTs of polio serum antibody in children without enteroviruses was 1.5 to 1.7 times as much as the GMTs of those with enteroviruses, and the difference was statistically significant. Overall, the results demonstrated that enterovirus infection interfered the immune response of vaccinates to TOPV to some extent. It was also suggested that supplemental immunization was the key measure in polio eradication program and should be conducted in winter or spring seasons.