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The interest in indole dearomatization, which serves as a useful tool in the total synthesis of related alkaloid natural products, has recently been renewed with the intention of developing new methods efficient in both yield and stereoselective control. Here, we report an enzymatic approach for the oxidative dearomatization of indoles in the asymmetric synthesis of a variety of furoindolines with a vicinal quaternary carbon stereogenic center. This approach depends on the activity of a flavin-dependent monooxygenase, TsrE, which is involved in the biosynthesis of bicyclic thiopeptide antibiotic thiostrepton. TsrE catalyzes 2,3-epoxidation and subsequent epoxide opening in a highly enantioselective manner during the conversion of 2-methyl-indole-3-acetic acid or 2-methyl-tryptophol to furoindoline, with up to >99 % conversion and >99 % ee under mild reaction conditions. Complementing current chemical methods for oxidative indole dearomatization, the TsrE activity-based approach enriches the toolbox in the asymmetric synthesis of products possessing a furoindoline skeleton.
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Flavinas/metabolismo , Indóis/metabolismo , Oxigenases de Função Mista/metabolismo , Tioestreptona/biossíntese , Flavinas/química , Indóis/química , Estrutura Molecular , Oxirredução , Tioestreptona/químicaRESUMO
The photocycloaddition reaction of benzene with alkenes has become a significant approach for organic chemists and thus has been frequently utilized as a key step in the total synthesis of natural products. In this mini-review, the recent developments in [4 + 2] and [2 + 2] photocycloaddition reactions will be emphasized in constructing core scaffolds of complex natural products. By combining them together, we aim to demonstrate the utility and reinstate the importance of this methodology.
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OBJECTIVE: To study the structure and function of human sperm mitochondria before and after the freezing-thawing process. METHODS: Human sperm from healthy donors were subjected to the slow freezing-thawing process, and the sperm mitochondrion-related indexes compared before and after cryopreservation. The ultrastructural changes of the mitochondria were observed under the projection electron microscope, the mitochondrial membrane potential (MMP) and seminal adenosine triphosphate (ATP) content measured by immunofluorescence labeling and ELISA, respectively, and the sperm oxidative stress related indexes detected before and after sperm cryopreservation. RESULTS: Electron microscopy showed loose structures and widened crests of the sperm mitochondria, some with vacuole-like changes after the freezing-thawing process. The sperm after cryopreservation, compared with those before it, exhibited significantly increased contents of oxygen free radicals (ï¼»11.6 ± 3.8ï¼½% vs ï¼»9.6 ± 4.1ï¼½%, P < 0.05) and malondialdehyde (ï¼»3.2 ± 1.4ï¼½ vs ï¼»2.3 ± 1.2ï¼½ nmol/108, P < 0.05), but decreased antioxidant capacity (ï¼»0.6 ± 0.4ï¼½ vs ï¼»0.9 ± 0.4ï¼½ nmol/108, P < 0.05), superoxide dismutase activity (ï¼»0.9 ± 0.4ï¼½ vs ï¼»9.1 ± 3.9ï¼½ nmol/108, P < 0.05), MMP (ï¼»52.2 ± 6.2ï¼½% vs ï¼»55.7 ± 4.9ï¼½%, P = 0.026) and ATP production (ï¼»56.5 ± 9.0ï¼½ vs ï¼»61.3 ± 10.4ï¼½ pmol/106, P = 0.014). CONCLUSIONS: The freezing-thawing process can cause ultrastructural disorder of human sperm mitochondria, reduce their membrane potential and decrease their ATP production.
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Preservação do Sêmen , Criopreservação , Congelamento , Humanos , Masculino , Mitocôndrias , EspermatozoidesRESUMO
OBJECTIVE: To comprehensively analyze the status quo of autologous sperm preservation in the human sperm bank in Beijing and better utilize the existing resources for the preservation of male fertility. METHODS: We retrospectively analyzed the geographical data and semen quality of 251 males with autologous sperm preservation in the Human Sperm Bank, Science and Technology Research Institute, National Health and Family Planning Commission of China from July 2006 to December 2016. RESULTS: The rate of autologous sperm preservation in the Human Sperm Bank was as low as 8.76% between July 2006 and December 2010 but increased annually by 119% on average from 2011 to 2013. Of the 251 males involved, 204 (81.27%) were aged 20ï¼39 years, 175 (69.72%) had bachelor's or master's degree, 223 (88.84%) had no child, 69 (27.49%) got less than 10 tubes of semen samples frozen, and 26 (10.36%) had their semen samples cryopreserved only once. The utilization rate of the cryopreserved sperm was only 5.58 % (n = 14). The main reason for autologous sperm preservation was carcinoma (55.78% ï¼»n = 140ï¼½), including blood cancer (22.31% ï¼»n = 66ï¼½), testicular cancer (13.15% ï¼»n = 33ï¼½) and other cancers (16.33% ï¼»n = 41ï¼½). Compared with the non-cancer males, the cancer patients had a significantly reduced mean sperm concentration (90.45 vs 60.53 ×106/ml, P < 0.05), total sperm count (311.3 vs 175.8 ×106, P < 0.05), percentage of progressively motile sperm (PMS) (49.21% vs 43.55%, P < 0.05) and recovery rate of PMS (68.13% vs 52.17%, P < 0.05). In the subgroups of testicular, blood and other cancers, the sperm concentration averaged 37.68, 57.98 and 90.69 ×106/ml, the semen volume 2.73, 2.82 and 3.41 ml, the total sperm count 93.29, 158.41 and 349.49 ×106, the percentage of PMS 45.32%, 43.47% and 44.49%, and the recovery rate of PMS 48.32%, 50.07% and 61.09%, respectively, the sperm concentration and total sperm count significantly lower in the testicular cancer patients than in the other two groups (P < 0.05). CONCLUSIONS: The number of the cases of autologous sperm preservation in Beijing is increasing year by year, and the majority of them are cancer patients. As most of the cancer patients have missed the best period for sperm preservation, sperm bank workers should endeavor to increase the public awareness of autologous sperm preservation.
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Criopreservação , Neoplasias , Preservação do Sêmen/estatística & dados numéricos , Bancos de Esperma , Adulto , Pequim , Humanos , Masculino , Estudos Retrospectivos , Análise do Sêmen , Contagem de Espermatozoides , Motilidade dos Espermatozoides , Espermatozoides , Adulto JovemRESUMO
By manipulating the reactivity of spiroindolenine species, a sequential Michael/retro-Mannich/Mannich reaction of ω-indol-3-yl α,ß-unsaturated ketones was developed. In the presence of 10â mol % of a chiral phosphoric acid as the catalyst, a series of 3-(indol-3-yl)-pyrrolidines were synthesized in high yields (up to 91 %) with excellent stereoselectivities (up to 92 % ee, >19:1 d.r.). The products obtained here undergo diverse functional-group transformations. The mechanistic proposal of this reaction is supported by DFT calculations.
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An enantioselective chemical synthesis of arene cis-dihydrodiols has been realized from 2-pyrones through sequential ytterbium-catalyzed asymmetric inverse-electron-demand Diels-Alder (IEDDA) reaction of 2-pyrones and retro-Diels-Alder extrusion of CO2 . By using this strategy, a series of substituted arene cis-dihydrodiols can be obtained efficiently with high enantioselectivity (>99 % ee in many cases). Based on this strategy, efficient and concise asymmetric total syntheses of (+)-MK7607 and 1-epi-(+)-MK7607 were accomplished.
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OBJECTIVE: This study aimed to investigate the effect and possible underlying mechanisms of high-fat diet-induced obesity on spermatogenesis in male rats. METHODS: A total of 45 male rats were randomly divided into control (n = 15, normal diet) and obesity groups (n = 30, high-fat diet) and were fed for 16 weeks. Body weight and organ indexes were determined after sacrifice. Indicators of reproductive function, including sperm count, sperm motility, apoptosis of spermatogenic cells, and oxidative stress levels, were measured. Serum metabolic parameters and reproductive hormones were also assayed. RESULTS: Compared with the control group, epididymal sperm motility in the obese rats was significantly decreased (P < 0.01). Morphological analysis of the obesity group showed vacuolar changes in seminiferous tubules, spermatogenic cell dysfunction, and increased apoptosis of spermatogenic cells in testicular tissue (P < 0.05). The calculated free testosterone (cFT) concentration in serum was decreased (P < 0.05), whereas the serum sex hormone-binding globulin (SHBG) level was significantly increased (P < 0.01). The superoxide dismutase (SOD) concentration decreased and the malondialdehyde (MDA) concentration increased in testis tissues; however, neither changes were statistically significant (P > 0.05). RESULTS: Nutritional obesity can damage spermatogenesis in male rats due to long-term effects on spermatogenesis.
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Dieta Hiperlipídica/efeitos adversos , Infertilidade Masculina/patologia , Obesidade/patologia , Espermatogênese/fisiologia , Animais , Dieta Hiperlipídica/tendências , Infertilidade Masculina/etiologia , Masculino , Obesidade/complicações , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Fatores de TempoRESUMO
OBJECTIVE: To investigate the prevalence of metabolic syndrome (MS) and its relationship with reproductive hormones in adult males in China. METHODS: Using the cluster and stratified sampling methods, we conducted an investigation among 3 600 adult males aged over 20 years in Hebei, Shaanxi and Jiangsu provinces. We obtained their reproductive hormone levels, biochemical indicators and basic body indexes and compared them between the two groups of subjects. RESULTS: A total of 3 332 valid serum samples were collected, which revealed a prevalence rate of MS of 38.5% in the adult males. Compared with the non-MS subjects, the MS males showed a significantly higher free testosterone index (FTI, 0.39 ± 0.15 vs 0.45 ± 0.19, P < 0.01) but lower levels of total testosterone (TT, ï¼»16.35 ± 4.78ï¼½ vs ï¼»13.37 ± 4.23ï¼½ nmo/L, P < 0.01) and sex hormone-binding globulin (SHBG, ï¼»47.13 ± 20.50ï¼½ vs ï¼»33.32 ± 14.91ï¼½ nmol/L, P < 0.01) and testosterone secretion index (TSI, 3.64 ± 1.92 vs 3.14 ± 1.80, P < 0.01). There were no statistically significant differences between the two groups in the levels of calculated free testosterone (cFT) and LH (P > 0.05). Spearman rank correlation analysis showed that the levels of serum TT and SHBG were correlated with all the indicators of MS (P < 0.01) except systolic blood pressure (SBP), while that of cFT only with the levels of high-density lipoprotein (HDL), fasting blood glucose (FBG) and SBP (P < 0.01). After adjusted for age, smoking, drinking, and body mass index (BMI), all the MS indicators were significantly associated with the SHBG level (P < 0.01), but not high blood pressure with the serum TT level (P > 0.05). After adjusted for the age, smoking, drinking, BMI and TT, the serum SHBG level was the main independent risk factor for MS (OR: 0.965, 95% CI: 0.958ï¼0.973, P < 0.01). CONCLUSIONS: The level of serum cFT is not correlated with while that of SHBG is the main independent risk factor for metabolic syndrome in adult males in China.
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OBJECTIVE: To study the effects of L-carnitine (LC) on cryopreserved human sperm. METHODS: Ten semen samples were collected from normal sperm donors, each divided into six groups, fresh ejaculate (FE), non-LC cryopreservation (non-LC), and cryopreservation with LC at 1 mmol/L (LC-1), 2.5 mmol/L (LC-2), 5 mmol/L (LC-3) and 10 mmol/L (LC-4), respectively. The optimal concentration of LC was identified based on the motility and motion parameters of the post-thaw sperm. The plasma membrane integrity (PMI) of the sperm was assessed by eosin-nigrosin staining, their mitochondrial membrane potential (MMP) monitored by JC-1 assay, and the level of sperm ROS measured by the fluorescent probe DCFH-DA, followed by analysis of the mechanisms of LC protecting sperm against cryopreservation injury. RESULTS: Compared with the sperm in the FE group, the post-thaw sperm in the non-LC and LC groups showed significantly decreased progressive motility, average path velocity (VAP), straight line velocity (VSP) and curvilinear velocity (VCP) (P < 0.05). In comparison with the non-LC group, the LC-3 group exhibited a remarkably higher percentage of progressively motile sperm (ï¼»41.9 ± 4.6ï¼½ vs ï¼»47.0 ± 4.3ï¼½%, P = 0.0261) and VAP (ï¼»34.9 ± 2.6ï¼½ vs ï¼»38.9 ± 4.2ï¼½ µm/s, P = 0.0152), indicating that the optimal concentration of LC was 5 mmol/L. Both PMI and MMP were significantly lower in the non-LC than in the FE group (ï¼»52.7 ± 5.7ï¼½ vs ï¼»75.5 ± 5.4ï¼½%, P < 0.01 and ï¼»44.5 ± 3.5ï¼½ vs ï¼»57.3 ± 4.4ï¼½%, P < 0.01), but higher in the LC groups (ï¼»70.1 ± 8.2ï¼½% and ï¼»50.3 ± 3.4ï¼½%) than in the non-LC group (P < 0.01 and P < 0.05). The level of sperm ROS, however, was markedly higher in the non-LC than in the FE group (ï¼»12.5 ± 3.9ï¼½ vs ï¼»6.8 ± 2.4ï¼½, P < 0.01) but lower in the LC groups (ï¼»8.4 ± 5.3ï¼½%) than in the non-LC group (P = 0.05). CONCLUSIONS: L-carnitine can improve the motility and motion parameters of cryopreserved human sperm by reducing sperm ROS, enhancing sperm mitochondrial membrane potential and protecting the sperm plasma membrane.
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Carnitina , Mitocôndrias , Preservação do Sêmen , Carnitina/farmacologia , Criopreservação , Humanos , Masculino , Mitocôndrias/fisiologia , Motilidade dos Espermatozoides , EspermatozoidesRESUMO
OBJECTIVE: To study the protective effect of Qilin Pills (QLP) on the reproductive function of rats with oligoasthenospermia (OAS) induced by tripterygium glycosides. METHODS: Twenty-eight male SD rats were randomly divided into a normal control, an OAS model control, a low-dose QLP, and a high-dose QLP group of equal number. OAS models were made in the latter three groups by intragastrical administration of tripterygium glycosides at 40 mg per kg of the body weight per day, and meanwhile the animals in the low- and high-dose QLP groups were treated with QLP at 1.62 and 3.24 g per kg of the body weight per day, respectively, while those in the OAS model group with normal saline, all for 30 consecutive days. Then all the rats were executed for obtaining the testis weight, testis viscera index, epididymal sperm concentration and motility, reproductive hormone levels, and antioxidation indexes and observation of the histomorphological changes of the testis tissue by HE staining. RESULTS: After 30 days of intervention, the low- and high-dose QLP groups, as compared with the OAS model controls, showed significantly improved epididymal sperm concentration (ï¼»14.57 ± 3.95ï¼½ and ï¼»39.71 ± 11.31ï¼½ vs ï¼»4.71 ± 1.25ï¼½ ×106/ml, P <0.05) and motility (ï¼»3.71 ± 1.11ï¼½ and ï¼»4.29 ± 1.80ï¼½ vs ï¼»0.57 ± 0.53ï¼½%, P <0.05), increased levels of sex hormone binding globulin (SHBG) (ï¼»94.83 ± 11.17ï¼½ and ï¼»88.05 ± 9.21ï¼½ vs ï¼»56.74 ± 8.29ï¼½ nmol/L, P <0.05) and free testosterone (FT) (ï¼»27.27 ± 3.63ï¼½ and ï¼»32.80 ± 2.51ï¼½ vs ï¼»22.81 ± 2.75ï¼½ nmol/L, P <0.05), decreased level of follicle-stimulating hormone (FSH) (ï¼»1.49 ± 0.62ï¼½ and ï¼»1.12 ± 0.83ï¼½ vs ï¼»1.71 ± 0.52ï¼½ mIU/ml, P <0.05), but no significant change in the total testosterone (TT) level. Meanwhile, the level of superoxide dismutase (SOD) was markedly elevated in the low- and high-dose QLP groups in comparison with the OAS model control group (ï¼»277.14 ± 15.84ï¼½ and ï¼»299.60 ± 20.83ï¼½ vs ï¼»250.04 ± 31.06ï¼½ U/ml, P <0.05) while that of reactive oxygen species (ROS) remarkably reduced (ï¼»397.61 ± 62.71ï¼½ and ï¼»376.84 ± 67.14ï¼½ vs ï¼»552.20 ± 58.07ï¼½ IU/ml, P <0.05). HE staining showed that QLP intervention significantly increased the layers and quantity of spermatogenic cells in the testicular seminiferous tubules of the OAS rats. CONCLUSIONS: QLP can effectively protect the reproductive system of oligoasthenospermia rats by raising sperm quality, elevating reproductive hormone levels, reducing oxidative stress injury, and improving histomorphology of the testis.
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Astenozoospermia/tratamento farmacológico , Medicamentos de Ervas Chinesas/farmacologia , Oligospermia/tratamento farmacológico , Substâncias Protetoras/farmacologia , Reprodução/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Animais , Astenozoospermia/induzido quimicamente , Epididimo , Hormônio Foliculoestimulante , Masculino , Oligospermia/induzido quimicamente , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Túbulos Seminíferos , Contagem de Espermatozoides , Superóxido Dismutase/análise , Testículo , Testosterona/sangue , TripterygiumRESUMO
Recent advances in dearomatization through halofunctionalization reactions are summarized in this Minireview. Two general categories of strategies are currently employed in this field. On one hand, the reaction can be initiated with electrophilic halogenation at an alkyne or alkene moiety. The resulting halonium ion intermediate is then captured by a pendant aromatic ring at the ipso position, affording the dearomatization product. On the other hand, electrophilic halogenation can directly take place at a substituted arene, and the final dearomatization product is furnished by deprotonation or intramolecular nucleophilic trap. Highly enantioselective variants have been realized in the latter case by organocatalysis or transition metal catalysis. By applying these methods, various valuable halogenated polycyclic molecular architectures have been obtained from readily available starting materials.
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The rapid and direct asymmetric synthesis of 3-(3a-indolyl)hexahydropyrroloindoline motifs is an extremely important part of the total synthesis of several alkaloid structures. Herein, an intermolecular, asymmetric cascade dearomatization reaction of indole acetamides with 3-indolylphenyliodonium salts has been developed. This protocol provides a straightforward access to 3-(3a-indolyl)hexahydropyrroloindolines bearing an all-carbon quaternary stereocenter at the C3 position of the indoline ring with high enantioselectivities. The utility of the protocol has been demonstrated by the formal asymmetric synthesis of folicanthine.
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Acetamidas/química , Cobre/química , Indóis/química , Catálise , Estrutura Molecular , EstereoisomerismoRESUMO
Significant advancements have been made in catalytic asymmetric α-C-H bond functionalization of ethers via carbenoid insertion over the past decade. Effective asymmetric catalytic systems, featuring a range of chiral metal catalysts, have been established for the enantioselective synthesis of diverse ether substrates. This has led to the generation of various enantioenriched, highly functionalized oxygen-containing structural motifs, facilitating their application in the asymmetric synthesis of bioactive natural products.
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Metastasis is a major contributing factor that affects the prognosis of melanoma patients. Nevertheless, the underlying molecular mechanisms involved in melanoma metastasis are not yet entirely understood. Here, we identified ubiquitin-specific protease 22 (USP22) as a pro-oncogenic protein in melanoma through screening the survival profiles of 52 ubiquitin-specific proteases (USPs). USP22 demonstrates a strong association with poor clinical outcomes and is significantly overexpressed in melanoma. Ablation of USP22 expression remarkably attenuates melanoma migration, invasion, and epithelial-mesenchymal transition in vitro and suppresses melanoma metastasis in vivo. Mechanistically, USP22 controls melanoma metastasis through the SIRT1/PTEN/PI3K pathway. In addition, we conducted an United States Food and Drug Administration-approved drug library screening and identified topotecan as a clinically applicable USP22-targeting molecule by promoting proteasomal degradation of USP22. Finally, we found that both pharmacological and genetic silence of USP22 sensitize RSL3-induced ferroptosis through suppressing the PI3K/Akt/mTOR pathway and its downstream SCD, and ferroptosis inhibitor could partly rescued the decreased lung metastasis by topotecan in vivo. Overall, our findings reveal a prometastatic role of USP22 and identify topotecan as a potent USP22-targeting drug to limit melanoma metastasis.
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Chiral phosphoric acid works together with Hoveyda-Grubbs II catalyst enabling highly efficient synthesis of enantioenriched tetrahydro-ß-carboline (up to 95% yield, 90% ee) through an olefin isomerization/Pictet-Spengler cascade reaction via sequential catalysis.
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Alcenos/química , Compostos Organometálicos/química , Ácidos Fosfóricos/química , Rutênio/química , Catálise , Estrutura Molecular , EstereoisomerismoRESUMO
OBJECTIVE: To study the characteristics of phenylalanine hydroxylase (PAH) gene mutations in patients with hyperphenylalaninemia from Jiangsu province by DNA sequencing, and to analyze the spectrum of PAH gene mutations. METHODS: A total of 70 patients and their parents were included in this study. All of the 13 exons and flanking introns of the PAH gene were analyzed with DNA sequencing. RESULTS: Forty five types of mutations were identified, which included 4 novel mutations (L37P, H107R, Q267L, S391T). A total of 125 mutations were identified in 140 alleles (89.3%). All mutations were detected in exons 2-3, 5-7, 9-12 and introns 2, 4, 7 and 8. Most mutations were found in exons 6, 7 and 12. EX6-96A > G, R243Q and R241C were the most common mutations. CONCLUSION: The mutational spectrum of Jiangsu province seems to be different from other regions. The spectrum can offer reliable information for genetic diagnosis of patients with hyperphenylalaninemia.
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Mutação , Fenilalanina Hidroxilase/genética , Fenilcetonúrias/enzimologia , Fenilcetonúrias/genética , Adulto , Sequência de Bases , China , Éxons , Feminino , Humanos , Recém-Nascido , Íntrons , Masculino , Dados de Sequência Molecular , Adulto JovemRESUMO
Whether and how innate antiviral response is regulated by humoral metabolism remains enigmatic. We show that viral infection induces progesterone via the hypothalamic-pituitary-adrenal axis in mice. Progesterone induces downstream antiviral genes and promotes innate antiviral response in cells and mice, whereas knockout of the progesterone receptor PGR has opposite effects. Mechanistically, stimulation of PGR by progesterone activates the tyrosine kinase SRC, which phosphorylates the transcriptional factor IRF3 at Y107, leading to its activation and induction of antiviral genes. SARS-CoV-2-infected patients have increased progesterone levels, and which are co-related with decreased severity of COVID-19. Our findings reveal how progesterone modulates host innate antiviral response, and point to progesterone as a potential immunomodulatory reagent for infectious and inflammatory diseases.
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COVID-19 , SARS-CoV-2 , Animais , Antivirais , COVID-19/genética , Humanos , Sistema Hipotálamo-Hipofisário , Imunidade Inata/genética , Camundongos , Sistema Hipófise-Suprarrenal , Progesterona/farmacologiaRESUMO
OBJECTIVE: To establish the methods for training green-hand laboratorians in standard semen analysis and evaluating the training results, and afford some reference for internal quality control and training in andrology laboratories in China. METHODS: We trained the green-hand technicians in standard semen analysis recommended by WHO Laboratory Manual for the Examination and Processing of Human Semen (5th ed), and evaluated the training results by assessing the trainees' performance in the examination of sperm concentration and motility by statistic analysis. RESULTS: After training, the coefficients of variation of the semen samples with high, middle and low sperm concentration achieved by the trainees were 7.72% and 3.38% and 4.49%, and those with high, middle and high motility were 7.82%, 8.09% and 6.62%, respectively. We used Bland-Altman's method to evaluate the consistency between the results obtained by the trainees and those by the trainers. For sperm concentration, 4.77% of the datum points were out of the 95% consistency interval, and the absolute value of the biggest difference between the trainees and trainers was 8 x 10(6)/ml within the 95% consistency interval. For sperm motility, 7.15% of the data points were out of the 95% consistency interval, and the absolute value of the biggest difference between the trainees and trainers was 10% within the 95% consistency interval. Two-way analysis of variance showed no significant differences in the results of sperm concentration and motility analyses between the trainees and trainers (P > 0.05). CONCLUSION: Training in standard semen analysis significantly improved the precision of semen analysis among the green-hand laboratorians. The training and assessment methods we established proved to be effective and feasible.
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Capacitação em Serviço , Pessoal de Laboratório/educação , Análise do Sêmen/normas , Humanos , Masculino , Controle de QualidadeRESUMO
OBJECTIVE: To investigate the mechanism of serum testosterone reduction, its relationship with metabolism, changes in the number and morphology of Leydig cells and endocrine function in aging male rats. METHODS: The levels of serum total testosterone (tT), LH, FSH, HDL, LDL, TG, TC, Glu, INS, IRG and LP were determined in young (9 mo) and aging rats (12, 15, 18 and 21 mo), with 6 in each group. The morphological changes of Leydig cells were observed under the microscope. The concentrations of testosterone secreted from the cultured Leydig cells with the stimulation of hCG and Forskolin were assayed. The apoptosis rates of Leydig cells were detected by TUNEL. The visceral fat was isolated and weighed, and the Lee's index calculated. All the above indexes were recorded and compared among different age groups. RESULTS: The aging rats showed a significant decrease in the levels of serum tT and TSI ([1.26 +/- 0.65] ng/ml and [0.07 +/- 0.65] ng/mIU) as compared with the young rats ([3.24 +/- 0.38] ng/ml and [0.21 +/- 0.01] ng/mIU) (P < 0.01). Obvious differences were found in the morphology of Leydig cells among different age groups. The T secretion of Leydig cells at 24, 48 and 72 h in aging rats was markedly decreased (P < 0.05) while their TUNEL positive rate remarkably increased in the aging rats (17.36% +/- 1.31%) compared with the young ones (7.02% +/- 1.05%) (P < 0.05). There were statistically significant differences between the young and aging rats in all the biochemical parameters including IRG, HDL, LDL, TG, TC and visceral fat content (P < 0.05), except the levels of serum Glu, INS and LP (P > 0.05). CONCLUSION: The serum T level and secreting capacity of Leydig cells are significantly lower in aging rats than in young ones, and the metabolic parameters undergo regular changes with the decreasing level of serum T. The reduction of testosterone in aging male rats may be associated with the decreased secreting capacity and number of Leydig cells and declined function of the pituitary.
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Envelhecimento , Células Intersticiais do Testículo/citologia , Células Intersticiais do Testículo/metabolismo , Testosterona/sangue , Animais , Masculino , Ratos , Ratos Sprague-Dawley , Testosterona/metabolismoRESUMO
Antibiotics produced by soil microorganisms have been widespread and have cured the most prevalent diseases since 1940s. However, recent bacterial resistance to existing antibacterial drugs is causing a public health crisis. The structure-activity relationship of antibiotics needs to be established to search for existing antibiotics-based next-generation drug candidates that can conquer the challenge of bacterial resistance preparedness, which relies on the development of highly efficient total synthesis strategies. The solid-phase strategy has become important to circumvent tedious intermediate isolation and purification procedures with simple filtrations. This review will give a brief overview of recent applications of solid-phase strategy in the total synthesis of antibiotics.