Ni-catalyzed enantioconvergent deoxygenative reductive cross-coupling of unactivated alkyl alcohols and aryl bromides

Transition metal-catalyzed enantioconvergent cross-coupling of an alkyl precursor presents a promising method for producing enantioenriched C(sp3) molecules. Because alkyl alcohol is a ubiquitous and abundant family of feedstock in nature, the direct reductive coupling of alkyl alcohol and aryl halide enables efficient access to valuable compounds. Although several strategies have been developed to overcome the high bond dissociation energy of the C - O bond, the asymmetric pattern remains unknown. In this report, we describe the realization of an enantioconvergent deoxygenative reductive cross-coupling of unactivated alkyl alcohol (β-hydroxy ketone) and aryl bromide in the presence of an NHC activating agent. The approach can accommodate substituents of various sizes and functional groups, and its synthetic potency is demonstrated through a gram scale reaction and derivatizations into other compound families. Finally, we apply our convergent method to the efficient asymmetric synthesis of four β-aryl ketones that are natural products or bioactive compounds.

[Preliminary study on the relationship between biological rhythm changes and pregnancy complications during pregnancy]

To study the characteristics of heart rate rhythm in pregnant women at different trimester of pregnancy, and to explore the relationship between the basic rhythm of heart rate and pregnancy complications. Thirteen pregnant women who were diagnosed with normal early pregnancy in the Reproductive Center of the Second Affiliated Hospital of Soochow University from June 2018 to December 2019 were prospectively selected. Personal files were created and the heart rate data of pregnancy women was collected 24 hours a day by wearable devices until delivery. Prenatal examination and pregnancy outcomes were surveyed at follow-up. The cosine analysis method and the designed statistical module were used to analyze the long-term rhythm of pregnant women's heart rate. The heart rate of pregnant women showed a significant rhythm at different gestational weeks. Compared with the gestational week of 12, the midline-estimating statistic of rhythm(MESOR) increased significantly at the gestational week of 28 and 32 (t=-2.751,P=0.013;t=-2.314,P=0.032).The phase of rhythm shifted from 14∶00 pm in the first trimester of pregnancy (12 weeks) to 16∶00 pm in the second trimester (24 weeks) (t=2.613,P=0.018) and returned to 14∶00 pm at the third trimester (32 weeks) (t=-2.176,P=0.046). Season had no significant effect on the changes of MESOR, amplitude and phase of maternal heart rate in the first trimester (t=-0.356,P=0.729;t=-0.777,P=0.464;t=-0.434,P=0.673), while season had no significant effect on the changes of MESOR, amplitude and phase in the third trimester (t=-0.663,P=0.532;t=-0.209,P=0.841;t=0.625,P=0.592). The heart rate of one pregnant woman with natural delivery had rhythm disorder from the start of labor to delivery. The heart rate of one pregnant woman with premature rupture of membranes showed rhythm disorder before and after the rupture of membranes, and smaller amplitude. Rhythm disturbance may play a suggestive role in preterm delivery and labor initiation. In conclusion, pregnancy may cause changes in the internal heart rate rhythm. Maternal internal rhythm disturbance may occur when delivery or premature rupture of membranes occurs. The heart rate rhythm of pregnant women may be related to some common complications of pregnancy such as premature rupture of membranes.

[HbA1c comparison and diagnostic efficacy analysis of multi center different glycosylated hemoglobin detection systems]

Objective: Compare and analyze the results of the domestic Lanyi AH600 glycated hemoglobin analyzer and other different detection systems to understand the comparability of the detection results of different detectors, and establish the best cut point of Lanyi AH600 determination of haemoglobin A1c (HbA1c) in the diagnosis of diabetes. Methods: Multi center cohort study was adopted. The clinical laboratory departments of 18 medical institutions independently collected test samples from their respective hospitals from March to April 2022, and independently completed comparative analysis of the evaluated instrument (Lanyi AH600) and the reference instrument HbA1c. The reference instruments include four different brands of glycosylated hemoglobin meters, including Arkray, Bio-Rad, DOSOH, and Huizhong. Scatter plot was used to calculate the correlation between the results of different detection systems, and the regression equation was calculated. The consistency analysis between the results of different detection systems was evaluated by Bland Altman method. Consistency judgment principles: (1) When the 95% limits of agreement (95% LoA) of the measurement difference was within 0.4% HbA1c and the measurement score was≥80 points, the comparison consistency was good; (2) When the measurement difference of 95% LoA exceeded 0.4% HbA1c, and the measurement score was≥80 points, the comparison consistency was relatively good; (3) The measurement score was less than 80 points, the comparison consistency was poor. The difference between the results of different detection systems was tested by paired sample T test or Wilcoxon paired sign rank sum test; The best cut-off point of diabetes was analyzed by receiver operating characteristic curve (ROC). Results: The correlation coefficient R² of results between Lanyi AH600 and the reference instrument in 16 hospitals is≥0.99; The Bland Altman consistency analysis showed that the difference of 95% LoA in Nanjing Maternity and Child Health Care Hospital in Jiangsu Province (reference instrument: Arkray HA8180) was -0.486%-0.325%, and the measurement score was 94.6 points (473/500); The difference of 95% LoA in the Tibetan Traditional Medical Hospital of TAR (reference instrument: Bio-Rad Variant II) was -0.727%-0.612%, and the measurement score was 89.8 points; The difference of 95% LoA in the People's Hospital of Chongqing Liang Jiang New Area (reference instrument: Huizhong MQ-2000PT) was -0.231%-0.461%, and the measurement score was 96.6 points; The difference of 95% LoA in the Taihe Hospital of traditional Chinese Medicine in Anhui Province (reference instrument: Huizhong MQ-2000PT) was -0.469%-0.479%, and the measurement score was 91.9 points. The other 14 hospitals, Lanyi AH600, were compared with 4 reference instrument brands, the difference of 95% LoA was less than 0.4% HbA1c, and the scores were all greater than 95 points. The results of paired sample T test or Wilcoxon paired sign rank sum test showed that there was no statistically significant difference between Lanyi AH600 and the reference instrument Arkray HA8180 (Z=1.665,P=0.096), with no statistical difference. The mean difference between the measured values of the two instruments was 0.004%. The comparison data of Lanyi AH600 and the reference instrument of all other institutions had significant differences (all P<0.001), however, it was necessary to consider whether it was within the clinical acceptable range in combination with the results of the Bland-Altman consistency analysis. The ROC curve of HbA1c detected by Lanyi AH600 in 985 patients with diabetes and 3 423 patients with non-diabetes was analyzed, the area under curve (AUC) was 0.877, the standard error was 0.007, and the 95% confidence interval 95%CI was (0.864, 0.891), which was statistically significant (P<0.001). The maximum value of Youden index was 0.634, and the corresponding HbA1c cut point was 6.235%. The sensitivity and specificity of diabetes diagnosis were 76.2% and 87.2%, respectively. Conclusion: Among the hospitals and instruments currently included in this study, among these four hospitals included Nanjing Maternity and Child Health Care Hospital in Jiangsu Province (reference instrument: Arkray HA8180), Tibetan Traditional Medical Hospital of TAR (reference instrument: Bio-Rad Variant Ⅱ), the People's Hospital of Chongqing Liang Jiang New Area (reference instrument: Huizhong MQ-2000PT), and the Taihe Hospital of traditional Chinese Medicine in Anhui Province (reference instrument: Huizhong MQ-2000PT), the comparison between Lanyi AH600 and the reference instruments showed relatively good consistency, while the other 14 hospitals involved four different brands of reference instruments: Arkray, Bio-Rad, DOSOH, and Huizhong, Lanyi AH600 had good consistency with its comparison. The best cut point of the domestic Lanyi AH600 for detecting HbA1c in the diagnosis of diabetes is 6.235%.

[A real-world study of the effects of endocrine therapy on liver function in breast cancer]

Objective: To compare the effect of different endocrine therapy drugs on liver function in patients with early breast cancer. Methods: A retrospective cohort study was conducted to include 4 318 patients with early breast cancer who received adjuvant endocrine therapy in Department of Breast Surgery, Peking Union Medical College Hospital from January 1, 2013 to December 31, 2021. All the patients were female, aged (51.2±11.3) years (range: 20 to 87 years), including 1 182 patients in the anastrozole group, 592 patients in the letrozole group, 332 patients in the exemestane group, and 2 212 patients in the toremifene group. The mixed effect model was used to analyze and compare the liver function levels of patients at baseline, 6, 12, 18, 24, 36, 48, 60 months of medication, and 1 year after drug withdrawal among the three aromatase inhibitors (anastrozole, letrozole, exemestane) and toremifene. Results: ALT and AST of the 4 groups were significantly higher than the baseline level at 6 months (all P<0.01), and there were no significant differences in total bilirubin, direct bilirubin and AST levels among all groups one year after drug withdrawal (P: 0.538, 0.718, 0.061, respectively). There was no significant difference in the effect of all groups on AST levels (F=2.474, P=0.061), and in the effect of three aromatase inhibitors (anastrozole, letrozole, and exemestane) on ALT levels (anastrozole vs. letrozole, P=0.182; anastrozole vs. exemestane, P=0.535; letrozole vs. exemestane, P=0.862). Anastrozole and letrozole had significantly higher effects on ALT levels than toremifene (P<0.01, P=0.009). The proportion of abnormal liver function in each group increased significantly at 6 months compared with baseline, and then the proportion showed a decreasing trend over time. Conclusions: Three aromatase inhibitors (anastrozole, letrozole, and exemestane) and toremifene can significantly increase the level of ALT and AST in patients with breast cancer, and the levels can gradually recover to the baseline after 1 year of drug withdrawal. The effect of non-steroidal aromatase inhibitors (anastrozole, letrozole) on ALT levels is greater than toremifene.

[Alteration of Wnt3a overexpression and its early monitoring value during hepatocellular carcinogenesis]

Objective: To investigate the dynamic expression pattern of carcinoembryonic Wnt3a and its early monitoring value using a hepatocellular carcinoma model. Methods: Forty-eight Sprague Dawley (SD) rats were fed with pellet feed containing 2-acetylaminofluorene (2-AAF, 0.05%) to induce hepatocarcinogenesis, and control rats were fed a pellet diet. Liver tissue and blood samples were collected every two weeks. Liver tissues were pathologically examined using HE staining and grouped. The gene and Wnt3a mRNA expression were analyzed by genome-wide microarray. The expression and distribution of Wnt3a in liver tissue were analyzed by immunohistochemistry. Wnt3a concentration in liver tissue and serum was quantified by enzyme-linked immunosorbent assay. Statistical methods such as χ² test, Mann-Whitney test and analysis of variance were used to analyze the differences between groups. Results: According to the pathological examination results, the rat livers were divided into four groups: control, hepatocyte degeneration, precancerous lesions and hepatocellular carcinoma. Genome-wide expression profiling analysis and comparison with the control group revealed that 268 and 312 genes were up-regulated and 57 and 201 genes were down-regulated in the precancerous and cancerous group when signal logarithm ratio (SLR) was >8 log₂^cy5/cy3, and these significantly altered genes mainly involved in cell proliferation, signal transduction, tumor metastasis, and apoptosis. The expression of Wnt3a at mRNA level was significantly increased in all stages of cancer induction, including degeneration group (1.15±0.24, q=8.227), precancerous group (1.85±0.18, q=12.361) and cancerous group (2.59±0.55, q=18.082). Compared with the control group (0.25±0.11, F=121.103, P<0.001), the degeneration group, the precancerous group and the liver cancer group were up-regulated by 4.6, 7.4 and 10.4-folds, respectively. Immunohistochemistry showed that compared with the control group, the positive rate of Wnt3a in the degeneration group was 66.7% (12/18, χ²=10.701, P=0.001), and both the precancerous and liver cancer groups were positive (9/9, χ²=17.115, P<0.001). Wnt3a expression was gradually increased in liver and blood samples during the process of carcinogenesis, and the difference between two groups was statistically significant (F=176.711, P<0.001). Wnt3a overexpression was secreted into blood stream via cancerous liver tissue, and there was a linear correlation between Wnt3a levels in blood and liver samples (r=0.732, P<0.001). Conclusions: Wnt3a overexpression is closely related with hepatocellular carcinogenesis, and thus may become a new monitoring marker.

Construction of sulfur-containing N-vinylimides: N-addition of imides to propargyl sulfonium salts

An N-addition reaction between imides and propargyl sulfonium salts was developed to afford sulfur-containing N-vinylimides with moderate to excellent yields. Under the activation of NaOAc·3H₂O, imides could undergo deprotonation and propargyl sulfonium salts could isomerize to allenic sulfonium salts. The N-nucleophilic attack initiates the reaction and gives the desired products. Various imides, including arylimides, aliphatic imides and N-(arylsulfonyl) alkyl acylamides, and even bioactive saccharin, thalidomide and pomalidomide could provide organosulfur N-vinylimides compounds. The simple, mild and metal-free reaction conditions, the broad scope of substrates, gram-scale synthesis and convenient transformation embody the synthetic superiority of this process.

An N-addition reaction between imides and propargyl sulfonium salts was developed to afford sulfur-containing N-vinylimides with moderate to excellent yields.

[Expression of tuftelin protein and its clinical value in HBV-related liver cancer tissues]

Objective: To analyze the expression of tuftelin protein (TUFT1) and its clinical value in hepatocellular carcinoma (HCC)-related liver cancer tissues. Methods: The biological information data of TUFT1 mRNA expression in liver cancer and non-cancer tissues were analyzed from the TCGA and Oncomine database. After the approval of the ethics committee, the self-pairing method was used to collect the postoperative cancer and para-carcinoma tissues of 132 HCC cases hospitalized between January 2009 and December 2014. Tissue microarray and immunohistochemistry (IHC) were used to analyze the expression of TUFT1 in liver tissues. According to IHC staining, liver cancer was divided into high TUFT1 and low/no expression group. Combined with clinical data, the clinicopathological characteristics were statistically analyzed between and within the groups. The 5-year overall survival (OS) and disease-free survival (DFS) was analyzed by correlation analysis. Results: IHC staining showed that TUFT1 in cancer tissue was localized in the cytoplasm and cell membrane, and its positive expression rate was significantly higher in the liver cancer group (87.1%) than the para-carcinoma group (64.4%) (χ (2) = 18.563, P < 0.001). TUFT1 expression intensity in patients with liver cancer was significantly correlated with HBeAg positive (χ (2) = 4.080, P = 0.043), tumor size (χ (2) = 9.388, P = 0.002), vascular invasion (χ (2) = 14.885, P < 0.001), TNM stage (χ (2) = 13.516, P < 0.001) and ascites (χ (2) = 5.940, P = 0.015). TUFT1 high expression was negatively correlated with OS and DFS (P < 0.001). Conclusion: The overexpression of TUFT1 is closely related to HBV replication, vascular invasion and poor prognosis, and it is expected to become a useful marker for liver cancer diagnosis and prognosis.

[A comparative study of breast cancer mass screening and opportunistic screening in Chinese women]

Objective: To compare the population characteristics, the positive rate of screening, the detection rate of breast cancer, early diagnosis rate and the cost between the mass screening group and opportunistic screening group of breast cancer. Methods: This study is a prospective multicenter cohort study conducted from January 1, 2014 to December 31, 2016. The participants were enrolled for mass screening or opportunistic screening of breast cancer. After completing the questionnaire, all the participants received breast physical examination and breast ultrasound examination every year for 3 rounds by year. The participants' characteristics and screening results of the two groups were compared by χ² test, Fisher exact test or Wilcoxon rank-sum test. Results: A total of 20 080 subjects were enrolled. In the mass screening group, 9 434 (100%), 8 111 (85.98%) and 3 940 (41.76%) cases completed the 3 rounds of screening, and 10 646 (100%), 6 209 (58.32%) and 2 988 (28.07%) cases in the opportunistic screening group, respectively. In the opportunistic screening group, the proportions of less than 3 months lactation (1 275/9 796 vs. 1 061/8 860, χ²=4.597, P=0.032), non-fertility (850/10 646 vs. 574/9 434, χ²=27.400, P<0.01), abortion history (6 384/10 646 vs. 5 062/9 434, χ²=81.232, P<0.01), postmenopausal (2 776/10 646 vs. 2 217/9 434, χ²=17.757, P<0.01), long-term oral contraceptives(>6 months) (171/10 646 vs. 77/9 434, χ²=25.593, P<0.01) and family history of breast cancer in first-degree relatives (464/10 646 vs. 236/9 434, χ²=51.257, P<0.01) were significantly higher than those in mass screening group. The positive rate of screening (514/10 646 vs. 128/9 434, χ²=194.736, P<0.01), the detection rate of breast cancer (158/10 646 vs. 13/9 434, χ²=107.374, P<0.01), and positive rate of biopsy (158/452 vs. 13/87, χ²=13.491, P<0.01) in the opportunistic screening group were significantly higher than those of the mass screening group. The early diagnosis rate of the mass screening group was significantly higher than the opportunistic screening group (10/12 vs. 66/141, χ²=5.902, P=0.015). The average cost for detecting each breast cancer case of the mass screening group was 215 038 CNY, which was 13.6 times of the opportunistic screening group (15 799 CNY/case). In the opportunistic screening group, the positive rate of biopsy in primary hospitals was significantly lower than that in large-volume hospitals (79/267 vs. 79/185, χ²=8.267, P=0.004), but there was no significant difference in the mass screening group (6/37 vs. 7/50, χ²=0.082, P=0.774). Conclusions: Breast cancer screening can improve early detection rate. Compared with the mass screening mode, the opportunistic screening mode has the advantages of higher proportion of high-risk factors, higher positive rate of screening, higher detection rate of breast cancer, higher positive rate of biopsy, and lower cost of screening. However, the early diagnosis rate of breast cancer of opportunistic screening is lower than that of mass screening. The positive rate of opportunistic screening in primary hospitals is lower than that of large-volume hospitals. The two screening modes have their own advantages and should be chosen according to local conditions of different regions in China.

Direct Intermolecular Anti-Markovnikov Hydroazidation of Unactivated Olefins

We herein report a direct intermolecular anti-Markovnikov hydroazidation method for unactivated olefins, which is promoted by a catalytic amount of bench-stable benziodoxole at ambient temperature. This method facilitates previously difficult, direct addition of hydrazoic acid across a wide variety of unactivated olefins in both complex molecules and unfunctionalized commodity chemicals. It conveniently fills a synthetic chemistry gap of existing olefin hydroazidation procedures, and thereby provides a valuable tool for azido-group labeling in organic synthesis and chemical biology studies.

Combined inorganic base promoted N-addition/[2,3]-sigmatropic rearrangement to construct homoallyl sulfur-containing pyrazolones

The first sequentially combined inorganic base promoted N-addition/[2,3]-sigmatropic rearrangement reaction of α-alkylidene pyrazolinones and propargyl sulfonium salts has been reported to construct homoallyl sulfur-containing pyrazolones with moderate to excellent yields. α-Alkylidene pyrazolinones function as N-nucleophilic agents distinguished from the reported C-addition reactions. Propargyl sulfonium salts were first involved in the [2,3]-sigmatropic rearrangement protocol differentiated from the well-established annulation reactions. The excellent regioselectivity, the broad scope of substrates, gram-scale synthesis and convenient transformation embody the synthetic superiority of this cascade process.

The combined inorganic base promoted N-addition/[2,3]-sigmatropic rearrangement of α-alkylidene pyrazolinones and propargyl sulfonium salts has been reported to construct homoallyl sulfur-containing pyrazolones with moderate to excellent yields.

Enantioselective Synthesis of Oseltamivir Phosphate (Tamiflu) via the Iron-Catalyzed Stereoselective Olefin Diazidation

We herein report a gram-scale, enantioselective synthesis of Tamiflu, in which the key trans-diamino moiety has been efficiently installed via an iron-catalyzed stereoselective olefin diazidation. This significantly improved, iron-catalyzed method is uniquely effective for highly functionalized yet electronically deactivated substrates that have been previously problematic. Preliminary catalyst structure-reactivity-stereoselectivity relationship studies revealed that both the iron catalyst and the complex substrate cooperatively modulate the stereoselectivity for diazidation. Safety assessment using both differential scanning calorimetry (DSC) and the drop weight test (DWT) has also demonstrated the feasibility of carrying out this iron-catalyzed olefin diazidation for large-scale Tamiflu synthesis.

Iron-Catalyzed Direct Olefin Diazidation via Peroxyester Activation Promoted by Nitrogen-Based Ligands

We herein report an iron-catalyzed direct diazidation method via activation of bench-stable peroxyesters promoted by nitrogen-based ligands. This method is effective for a broad range of olefins and N-heterocycles, including those that are difficult substrates for the existing olefin diamination and diazidation methods. Notably, nearly a stoichiometric amount of oxidant and TMSN₃ are sufficient for high-yielding diazidation for most substrates. Preliminary mechanistic studies elucidated the similarities and differences between this method and the benziodoxole-based olefin diazidation method previously developed by us. This method effectively addresses the limitations of the existing olefin diazidation methods. Most notably, previously problematic nonproductive oxidant decomposition can be minimized. Furthermore, X-ray crystallographic studies suggest that an iron-azide-ligand complex can be generated in situ from an iron acetate precatalyst and that it may facilitate peroxyester activation and the rate-determining C-N₃ bond formation during diazidation of unstrained olefins.

[Impact of the 21-gene recurrence score assay in clinical treatment and prognosis analysis for patients with hormone receptor positive early-stage breast cancer]

Objective: To explore the association between the 21-gene recurrence score (RS) and clinicopathologic characteristics as well as prognosis in patients with axillary lymph node negative, hormone receptor (HR) positive breast cancer. Methods: The clinicopathologic data of 439 early breast cancer patients who underwent 21 gene RS testing was retrospectively analyzed. According to the 21 gene RS, the patients were divided into low risk (295 cases), intermediate risk (111 cases) and high-risk (33 cases) group. The relationship between the 21 gene RS and clinicopathological characteristics, treatment, recurrence and metastasis was analyzed. Univariate and multivariate statistical analyses were used to analyze the risk factors for relapse free survival (RFS). Results: Tumor grade, estrogen receptor (ER), progesterone receptor (PR) and Ki-67 index were significantly different among the 3 risk cohorts (P<0.001 for all). After a median follow-up of 32 months, the recurrence rate in low risk group (3.7%) was significantly lower than that in the intermediate-high risk group (9.0%), the locoregional recurrence (LRR) rate of low, intermediate and high risk group was 2.4%, 6.3% and 9.1%; and the distant metastasis (DM) rate in low risk group was 1.4% and 2.1% in the intermediate-high risk group. Univariate analysis showed RS, ER status and endocrine therapy were prognostic factors for RFS (P<0.05 for all). Multivariate analysis showed that RS was an independent significant predictor for RFS (P=0.04). Conclusions: The 21-gene RS is related to tumor grade, ER, PR and Ki-67 index. RS is an independent risk factor for RFS in patients with hormone receptor positive early-stage breast cancer.

[Impact of the 21-gene recurrence score assay in clinical treatment and prognosis analysis for patients with hormone receptor positive early-stage breast cancer]

Objective: To explore the association between the 21-gene recurrence score (RS) and clinicopathologic characteristics as well as prognosis in patients with axillary lymph node negative, hormone receptor (HR) positive breast cancer. Methods: The clinicopathologic data of 439 early breast cancer patients who underwent 21 gene RS testing was retrospectively analyzed. According to the 21 gene RS, the patients were divided into low risk (295 cases), intermediate risk (111 cases) and high-risk (33 cases) group. The relationship between the 21 gene RS and clinicopathological characteristics, treatment, recurrence and metastasis was analyzed. Univariate and multivariate statistical analyses were used to analyze the risk factors for relapse free survival (RFS). Results: Tumor grade, estrogen receptor (ER), progesterone receptor (PR) and Ki-67 index were significantly different among the 3 risk cohorts (P<0.001 for all). After a median follow-up of 32 months, the recurrence rate in low risk group (3.7%) was significantly lower than that in the intermediate-high risk group (9.0%), the locoregional recurrence (LRR) rate of low, intermediate and high risk group was 2.4%, 6.3% and 9.1%; and the distant metastasis (DM) rate in low risk group was 1.4% and 2.1% in the intermediate-high risk group. Univariate analysis showed RS, ER status and endocrine therapy were prognostic factors for RFS (P<0.05 for all). Multivariate analysis showed that RS was an independent significant predictor for RFS (P=0.04). Conclusions: The 21-gene RS is related to tumor grade, ER, PR and Ki-67 index. RS is an independent risk factor for RFS in patients with hormone receptor positive early-stage breast cancer.

LncRNA SNHG12 promotes cell growth and inhibits cell apoptosis in colorectal cancer cells

Several long non-coding RNA (lncRNA) might be correlated with the prognosis of colorectal cancer (CRC) and serve as a diagnostic and prognostic biomarker. However, the exact expression pattern of small nucleolar RNA host gene 12 (SNHG12) in colorectal cancer and its clinical significance remains unclear. The level of SNHG12 was detected by qRT-PCR in CRC tissues and CRC cells. MTT assay and colony formation assay were performed to examine the cell proliferation of CRC cells transfected with pcDNA-SNHG12 or si-SNHG12. Flow cytometry technology was used to detect cell cycle and cell apoptosis of CRC cells transfected with pcDNA-SNHG12 or si-SNHG12. The protein level of cell cycle progression-related molecules, including cyclin-dependent kinases (CDK4, CDK6), cyclin D1 (CCND1) and cell apoptosis-related molecule caspase 3 was detected by western blot. The effect of SNHG12 knockdown was examined in vivo. Increased levels of SNHG12 were observed in CRC tissues and in CRC cells. SNHG12 promoted the cell proliferation of CRC cells. In addition, SNHG12 overexpression boosted the cell cycle progression of SW480 cells transfected with pcDNA-SNHG12 and SNHG12 knockdown inhibited the cell cycle progression of HT29 cells transfected with si-SNHG12. SNHG12 also inhibited the cell apoptosis of CRC cells. We also found that SNHG12 increased the expression of cell cycle-related proteins and suppressed the expression of caspase 3. Our results suggest that SNHG12 promoted cell growth and inhibited cell apoptosis in CRC cells, indicating that SNHG12 might be a useful biomarker for colorectal cancer.

Correlation between quantitative severity of stress thallium-201 myocardial perfusion defect and severity of coronary stenosis

The correlation between the quantitative myocardial perfusion defect severity of stress 201Tl single-photon emission computed tomography and the severity of coronary stenosis was investigated in 28 patients with angina pectoris. Among the 28 patients, four had normal or nearly normal coronary angiograms, seven had one-vessel disease, six had two-vessel disease and 11 had three-vessel disease. Seven patients had prior myocardial infarctions and two had collateral flows to the diseased vessels. The quantitative 201Tl defect severity score was obtained by summing the standard deviations of each pixel in which the counts fell > 2.5 SD below the mean normal counts. The severity of coronary stenosis was expressed as the Gensini score. The quantitative 201Tl defect severity score correlated significantly with the Gensini score. In patients without prior myocardial infarction or collateral flow, a more significant correlation between the quantitative 201Tl defect severity score and the Gensini score was found. Quantitative analysis of stress 201Tl defect severity provides a useful, noninvasive assessment of the functional severity of coronary stenosis compared with coronary angiography.

[The immune reconstitution in Scid mice and the effect of T, B, NK cells on the growth potential of CNE-2Z-H5 transplanted tumor]

CNE-2Z-H5 was transplanted into the Scid mice of which immune system was reconstituted with the peripheral lymphocytes or thymus of the isogenetic mice and the BALB/c nude mice of which NK cells were inhibited with cyclophosphamide. The results showed that the growth speed and weight of the tumors were in order from high to low among groups of Scid mice, BALB/c nude mice with NK inhibited, BALB/c nude mice, Scid mice with immune reconstitution. The transplanted tumor, in 6/6 cases injected beforehand with peripheral lymphocytes and 1/3 case transplanted accompanied with thymus disappeared within 22 days. The conclusion is that the immune reconstitution of Scid mice has succeeded and play an effective role in antitumor response.

Diagnosis of coronary artery disease using dipyridamole thallium-201 imaging

Dipyridamole thallium-201 imaging, using single-photon emission computed tomography, was evaluated for its safety and diagnostic efficacy in 109 patients with angiographically documented coronary artery disease and 35 normal subjects. The most common side effects after the intravenous administration of dipyridamole thallium-201 (0.56 mg/kg) included chest pain in 41 patients, dizziness in 20 patients, headache in 16 patients, and ST segment depression > or = 1 mm in 15 patients. Aminophylline was required to reverse the side-effects in 46 patients, and 45 of the 46 patients experienced complete relief of symptoms. Of the 109 patients with coronary artery disease, 104 had abnormal dipyridamole thallium images. The per patient sensitivity was 95%. Of the 35 normal subjects, 27 had normal thallium images. The per patient specificity was 77%. The sensitivity and specificity for the individual vessels were 84% and 87% for the left anterior descending artery, 67% and 97% for the left circumflex artery, and 89% and 85% for the right coronary artery, respectively. Dipyridamole thallium-201 imaging is a relatively safe noninvasive method and is an effective alternative to exercise thallium-201 scintigraphy for the diagnosis of coronary artery disease.

An unusual cystic lesion histologically similar to autosomal dominant polycystic kidney disease in a child with aniridia and del 11p13

The association of Wilms tumor with an interstitial deletion on the short arm of chromosome 11 is well established. Specifically, the 11p13 band has been implicated in the syndrome of Wilms tumor, aniridia, genitourinary abnormalities and mental retardation. Only rarely have other renal lesions been associated with the chromosomal abnormality del 11p13. We report a case of a segmental cystic lesion, histologically akin to autosomal dominant polycystic kidney disease, in a child with aniridia and the del (11)(p12p14) karyotype.

The role of Tamm-Horsfall mucoprotein in calcium oxalate crystallization. N-acetylcysteine--a new therapy for calcium oxalate urolithiasis

OBJECTIVE

To assess the role of Tamm-Horsfall mucoprotein (THM), obtained from normal subjects (nTHM) and stone-formers (sfTHM), on crystallization of calcium oxalate (CaOx) in whole urine, and to assess the effects of N-acetylcysteine (AC) in preventing renal stone formation.

MATERIALS AND METHODS

A modified rapid evaporation method was used to test the effects of THM and AC on crystallization of CaOx in vitro. Animal experiments involving 30 rats and a clinical study involving 17 patients with idiopathic CaOx urolithiasis were also performed to identify further the role of AC in preventing CaOx stone formation in vivo.

RESULTS

The results showed that the volume of CaOx crystals was greatly reduced, by ultrafiltration, to 39.1% of untreated urine, but increased to 81.4% by adding nTHM (35 mg/l). sfTHM was a more potent promoter. AC was found to inhibit the transformation of THM and lower the crystallization of CaOx both in vitro and in vivo.

CONCLUSION

We believe that the transformation of THM is an important step in the formation of urolithiasis. AC might be a new way to prevent renal stone formation and recurrence.

Evidence that the nodulation regulatory gene nodD3 of Rhizobium meliloti is transcribed from two separate promoters

The Bgl II fragment carried in plasmid pMH903, which covers the nodD3 region of Rhizobium meliloti, has been sequenced. By using both S1 nuclease mapping and primer extension, two transcription start sites were demonstrated in the sequence. After the first transcription start site, there were two open reading frames (ORF) followed by the nodD3 coding sequence which was also preceded by the second promoter. The nodD3 gene under the first promoter mediated high, constitutive expression of nodC-lacZ fusion, and the gene under the second promoter required the product of nodD1 and alfalfa (Medicago sativa) seed exudate for the activation of fusion. Nodulation experiments showed that the nodD3 gene under either promoter was functional in eliciting nodules on alfalfa. The deletion of part of the two ORFs after the first promoter or deletion of the second promoter did not block the constitutive expression of nodC-lacZ fusion, whereas the deletion of the first promoter region or a polar insertion mutation between the two promoters did cause nodD3 to activate nodC only in the presence of the inducer. It indicates that nodD3 can be transcribed from the first promoter as well as from a separate second promoter.

Inadvertent arterial administration of parenteral hyperalimentation solution resulting in generalized seizure activity

Serious complications may arise from improper central venous catheter placement. In this case report, seizures occurred as a result of inadvertent arterial administration of parenteral hyperalimentation. There is a need for radiographic confirmation of central venous catheter position by qualified personnel before catheter use.

Mechanistic studies of two amino acid racemases of broad substrate specificity from Pseudomonas striata and Aeromonas caviae

The conversion of L-[alpha-2H]alanine in H2O and unlabeled L-alanine in 2H2O into D-alanine, under nearly irreversible conditions, with the amino acid racemase from Pseudomonas striata showed significant internal transfer of the alpha-hydrogen. This result has been interpreted as being indicative of a single base mechanism for the racemization. The relative rates of deuterium incorporation into unlabeled D- and L-methionine by the two amino acid racemases of broad substrate specificity from P. striata and Aeromonas caviae, were measured in 2H2O. The results showed a markedly different pattern, dependent upon the configuration of the initial substrate; with D-methionine as substrate deuterium is incorporated into both enantiomers at approximately the same rate, but with L-methionine as substrate deuterium is incorporated considerably faster into the D than the L enantiomer. These results argue against a single base mechanism of racemization for these enzymes and are best rationalized in terms of a double base model where only one of the bases undergoes proton (deuterium) exchange with the solvent while the amino acid is enzyme-bound. The interpretation of the earlier experiment needs to be considered in light of these results.

Studies on heterologous expression of Rhizobium meliloti nifA gene and oxygen sensitivity of its product

When the R. meliloti (Rm) nifA'-lacZ fusion-carrying plasmids were introduced into the strains of Agrobacterium tumefaciens, R. trifolii and R. astragalus, beta-galactosidase activity was demonstrated. However, activity was not induced by microaerobiosis. Furthermore, R. meliloti nifA'-lacZ fusion was also not expressed in the nodule bacteroids of R. trifolii and R. astragalus. We speculate that some factor(s) important for the induction of Rm nifA presumed to be the fixLJ regulatory system would not be operative in these bacteria. Experiments using R. meliloti nifH'-lacZ/K. Pneumoniae nifH'-lacZ fusion and the constitutive Rm nifA system to test the nifA-dependent expression of nifH'-lacZ under aerobic and microaerobic conditions in E. coli were performed. The inhibition of the Rm nifA activation of nifH'-lacZ expression in the bacteria grown in the aerobic condition was shown. Assays on the Rm nifA-m RNA produced by the constitutive Rm nifA in E. coli under aerobic and microaerobic conditions with the cloned nifA as a probe for dot blot hybridization showed a marked decrease of Rm nifA mRNA when the bacteria were grown under aeration.

[Serotypes and epidemiological study of pneumococcal infection in 18 provinces (cities) in China]

During the years 1982 to 1985, 482 strains of S. pneumoniae were isolated from 482 patients of pneumococcal diseases in 18 provinces (cities) in China. There were 67 strains from the patients of pneumococcal pneumonia, 169 strains from pneumococcal meningitis and 246 strains from pneumococcal otitis media. Their serotypes and epidemiology were studied with following results. The rate of pneumococcal pneumonia, meningitis and otitis media was 14.26 cases, 79.08 cases and 68.14 cases per 1000 homologous disease cases, respectively. Most of the infections occurred at the infants while 73.7% pneumococcal meningitis, 63% otitis media and 40.3% pneumonia were in less than or equal to 3 age group. The mortality of patients with pneumococcal pneumonia was 16.4% and with pneumococcal meningitis was 16%. All of isolates of S. pneumoniae were identified using typing antisera (Statens Seruminstitut, Copenhagen). The main types were 5, 6, 1, 19, 2 and 14, which accounted for 56.8% (274 strains) of total number of strains. Type 5 was the most main serotype and accounted for 13.3% (63 strains).

Insulin-like growth factor-I messenger ribonucleic acid in the developing human placenta and in term placenta of diabetics

Fetal growth and development are dependent upon the growth and development of the placenta. Control of placental growth and development is little understood. Immunoreactive insulin-like growth factor-I and -II (IGF-I and IGF-II) have been shown to be released by human placental tissue and human placental membranes have been observed to contain specific receptors for these growth factors. Furthermore, we have demonstrated the presence of IGF-II mRNA transcripts in the developing human placenta and at gestational term in placentae of diabetics. Thus, the IGFs may have a regulatory role in the growth and development of the placenta via autocrine and/or paracrine mechanism(s) of action. In this report we demonstrate the presence of four differing size species of placental poly(A)+ RNA which specifically hybridize to an IGF-I probe originally isolated from an adult human liver cDNA library and localize IGF-I and IGF-II mRNA to syncytiotrophoblasts and fibroblasts, respectively, of the placenta by in situ hybridization. The major transcript is 7500 bases in size and the remaining three transcripts are 5000, 1100, and 900 bases in length with no apparent changes from these sizes throughout gestation and at term in diabetics. Quantification by densitometry of placental IGF-I mRNA detected by dot blot hybridization indicated that first and second trimester placentae each express more IGF-I mRNA relative to that expressed in placenta at term. These results suggest that there are developmental changes in the relative amount of IGF-I mRNA expressed in the human placenta. IGF-I is, therefore, most likely important early in gestation as a placental growth factor. This time period is critical for fetal development and growth, when embryonic induction, organogenesis, and rapid cell proliferation occur.

Isolation of an insulin-like growth factor II cDNA with a unique 5' untranslated region from human placenta

Human insulin-like growth factor II (IGF-II) cDNA from a placental library was isolated and sequenced. The 5' untranslated region (5'-UTR) sequence of this cDNA differs completely from that of adult human liver and has considerable base sequence identity to the same region of an IGF-II cDNA of a rat liver cell line, BRL-3A. Human placental poly(A)+ RNA was probed with either the 5'-UTR of the isolated human placental IGF-II cDNA or the 5'-UTR of the IGF-II cDNA obtained from adult human liver. No transcripts were detected by using the 5'-UTR of the adult liver IGF-II as the probe. In contrast, three transcripts of 6.0, 3.2, and 2.2 kilobases were detected by using the 5'-UTR of the placental IGF-II cDNA as the probe or the probe from the coding sequence. A fourth IGF-II transcript of 4.9 kilobases presumably containing a 5'-UTR consisting of a base sequence dissimilar to that of either IGF-II 5'-UTR was apparent. Therefore, IGF-II transcripts detected may be products of alternative splicing as their 5'-UTR sequence is contained within the human IGF-II gene or they may be a consequence of alternative promoter utilization in placenta.

Stereochemistry and mechanism of reactions catalyzed by tyrosine phenol-lyase from Escherichia intermedia

Stereochemical studies on tyrosine phenol-lyase from Escherichia intermedia have shown that the alpha, beta-elimination reactions of L-serine and D- and L-tyrosine proceed with retention of configuration at C-beta. Stereospecifically beta-tritiated L-serine is slowly racemized at C-beta. Deuterium from the alpha-position of L-tyrosine is partially transferred to C-4 of the phenol formed when the alpha, beta-elimination reaction is carried out in H2O, although no transfer of alpha-1H in 2H2O was seen. The result favors tautomerization of the p-hydroxyphenyl to a cyclohexadienonyl moiety prior to carbon-carbon bond cleavage. In the conversion of L- to D-alanine catalyzed by tyrosine phenol-lyase, some alpha-hydrogen recycling is observed, pointing to a single-base racemization mechanism. Attempts to demonstrate cofactor motion during racemization by NaBH4 reduction of [3H]PLP-enzyme: D- and L-alanine complexes failed, but showed that, as in other PLP enzymes, the holoenzyme is reduced preferentially from the Re face with respect to C-4' of PLP and enzyme-substrate complexes preferentially from the Si face.

Expression of insulin-like growth factor II in human placentas from normal and diabetic pregnancies

The growth and development of the placenta is critical to fetal growth and development; however, little is known regarding the mechanisms controlling placental growth and development. Human placental membranes are known to possess receptors for insulin-like growth factors I and II (IGF-I and IGF-II) from early gestation, and increasing evidence supports a major role for IGF-I and/or IGF-II in fetal growth and development. Therefore, the IGFs may also play a significant role in regulating placental growth and development. We report here that an adult human liver IGF-II cDNA hybridizes to poly(A)+ RNAs of human placentas from different gestational ages. There are four placental poly(A)+ RNA species that hybridize to IGF-II cDNA, the major one of which is about 6000 bases. The sizes of the hybridized transcripts are the same for placentas of different gestational ages. Furthermore, the IGF-II sequences expressed in the human placenta were quantitated by dot blot hybridization. The second trimester placenta expresses more IGF-II mRNA sequences than placenta of first trimester and term. Interestingly, the term placentas from diabetic pregnancies also express more of these sequences than those from normal pregnancies. These results suggest that there are developmental changes in the expression of the IGF-II gene in the placenta and that IGF-II may promote placental growth by way of an autocrine and/or paracrine mechanism. Moreover, fetuses developing in diabetic pregnancies receive a large influx of glucose, which in turn may stimulate the expression of IGF-II sequences in placenta, resulting in higher utilization of glucose and overgrowth of placenta. This may explain the macrosomia and high incidence of malformations and stillbirths known to result from pregnancies in diabetics.

Effect of nifA product on suppression of Nif- phenotype of gln mutation and constitutive synthesis of nitrogenase in Klebsiella pneumoniae

This paper describes the role of nifA product on the ammonia regulation of nitrogen fixation in K. pneumoniae. A plasmid carrying nifA gene under the promoter of tetracycline resistance gene was constructed. When this nifA carrying plasmid was introduced into a glnAG mutant, the Nif- phenotype of this gln mutant was suppressed. Furthermore, when the plasmid was introduced into the wild type and glnAG mutant, derepression of nitrogenase synthesis in ammonia occurred in both strains and the products of nif genes can be detected by two-dimensional gel electrophoresis in the extracts of these ammonia-grown bacterial cells. The constitutive synthesis of nitrogenase in NH4+ was also demonstrated in free living nitrogen-fixing bacteria, Enterobacter cloacae, when the bacteria received the plasmid carrying nifA gene from K. pneumoniae.

Effect of nifA gene product on expression of lacZ under nifH promoter in Escherichia coli

Gene expression of the nitrogen fixation system from Klebsiello pneumonice was studied in Escherichia coli by using compatible plasmids as vectors. One constructed plasmid carried the nifH promoter fused to the structural gene for beta-galactosidase, lac Z. Another plasmid carried the promoter of a tetracycline-resistance gene fused to nifA. We found that anaerobic synthesis of beta-galactosidase was greatly enhanced by the presence of an active nifA gene, indicating that its product is a positive control factor for transcription of nifH. In addition, anaerobic expression of lacZ was repressed by ammonium or serine in the presence of nifA. Thus the regulatory mechanism under study is of physiological relevance.