[Application of MRI in the diagnosis of cervical cancer].

Objective: Investigating the diagnostic value of MRI for cervical cancer, including preoperative staging, vagina involvement and lymph node metastasis is the aim of this pape. Methods: Select 116 patients with UCC of the second hospital of JiLin University from October 2016 to April 2019. All patients accept MRI examination. Ultimately, all patients accept surgical treatment. Use SPSS19.0 software to analyze MRI results of all the patients.Using the postoperative pathological results as the golden standard in the diagnosis of cervicalcancer diagnosis. The dates from the MRI preoperative staging, preoperative clinical staging and the postoperative pathologic staging were compared through chi-square test. And the dates of preoperative MRI in cervical cancer vagina involvement and lymph node metastasis diagnosis and postoperative pathological results were compared through Mcnemar chi-square test. The difference was statistically significant(P<0.05). Results: 1, The differences between MRI staging and the postoperative pathologic staging have no statistical significance (P>0.05), whilethe difference between MRI staging and preoperative clinical staging during was statistically significant (P<0.05). Using the postoperative pathological staging as the examination standards, the accuracy of preoperative clinical staging is only 67.5%, and cervical cancer overall preoperative MRI staging accuracy was 95%; 2, Preoperative MRI diagnosis and postoperative pathologic results in cervical vaginal involvement and lymph node metastasis has highsensitivity and specificity, were 97.0%, 96.2%, 93.2%, 97.8%. Checked by Mcnemar chi-square test, the differences between themhave no statisticalsignificance (P>0.05), namely the preoperative MRI diagnosis and postoperative pathological results have consistency in clinical. Conclusion: The combination of MRI and FIGO clinical stage can impro the accuracy of clinical staging of cervical cancer. MRI can be used as the important tool to assess cervical cancer preoperative staging, and to choose and formulate reasonable cervical cancer treatment plan.

[Correlation between fetal intracardiac echogenic foci and chromosome and heart function].

Objective: To study the relationship between the intracardiac echogenic foci and the abnormal chromosome and the changes of Cardiac function. Methods: A total of 2645 cases with the gestational age between 14 to 22 weeks were tested in the department of gynecology and obstetrics of the Second Hospital of Jilin University from Jan.2016 to Dec.2017.Seventy-nine of them existed the intracardiac echogenic foci, and the patient's imaging data in details were recorded.All of them have taken the non-invasive DNA examination.Fetal echocardiography was performed at 22-24 weeks.Karyotype analysis was performed using amniocentesis and umbilical cord blood puncture.Inducing labor was performed for fetuses that has been identified as a haploid or had a severely malformation during pregnancy.The other fetuses were followed up to the birth.Echocardiography was performed on neonates. Results: The detection rate of intracardiac echogenic focus was 3.0% in early pregnancy, 92% in the left ventricle, 4% in the right ventricle, and 4% in double ventricle.There were 5 cases of haploid fetus induced labor, 2 cases of induced labor due to fatal malformation.Fetal echocardiography revealed tricuspid regurgitation in 7 cases.One of them was induced labor in consideration of heart failure. Conclusions: 1.The risk of chromosomal abnormality in the fetus of isolated left intracardiac echogenic focus is lower.Non-invasive DNA examination has a high reliability that could be an important reference before an invasive antenatal diagnosis.2.A higher rate of fetal malformation will be found when the foci located in the right or double ventricle.3.The relationship between fetal intracardiac echogenic foci and fetal cardiac dysfunction needs to be further clarified.

[Relationship between the choroid plexus cyst and the aneuploidy].

Objective: Using the method of the ultrasound and the noninvasive DNA to find the relationship between the choroid plexus cyst and the aneuploidy, and to provide the meaningful data for prenatal consultant. Methods: A total of 112 cases, that the gestational age were between 13 and 20 weeks, which were diagnosed with choroid plexus cyst in the Department of Gynecology and Obstetrics of the Second Hospital of Jilin University from January. 2016 to July. 2017 were tested by ultrasonography. They all accepted the noninvasive DNA. At the same time, a total of 100 normal fetuses were randomly involved in the control group by the combination of gestational age and the age of the pregnant woman, all of them had taken the non-invasive DNA examination and followed up until the birth. Those fetuses who combined with other malformations were induced labor in the two groups. If the results of noninvasive DNA indicated the high-risk, invasive examination for karyotype analysis were recommended. If the results were aneuploidy, they chose induced labor. The rest cases followed up until the birth. Results: Five cases of the 112 fetuses in the case group were found with obvious malformation (3 of them were found in the early trimester, 2 of them were found in the middle trimester). The numbers of high risk results of noninvasive DNA were 7, and 5 of them underwent the invasive karyotype analysis. When the aneuploidy had diagnosed definitely, induced labor had been taken. One case was found to be the aneuploidy in the control group, and took the induced labor. One case was diagnosed as right side aortic arch by ultrasound in the control group, with a good prognosis. The other cases were followed up until the birth with a good prognosis. Conclusions: (1)In the early trimester, the fetus with choroid plexus cyst has an increasing risk of aneuploidy. (2)When the maximum diameter of choroid plexus cyst is less than 1 cm and the cyst was single, most of them could disappear in the middle trimester, it has no effect on the fetus. (3)Noninvasive DNA test has a high accuracy, which can improve the positive rate of invasive examination.

[Relationship between sonographic markers and fetal chromosome abnormality during 16-18 weeks of pregnancy].

Objective: To analysis of fetal ultrasound soft index positive cases during 16-18 weeks of pregnancy, and to explore the relationship with chromosomal abnormalities in order to increase the positive rate of invasive prenatal diagnosis and reduce the rate of missed diagnosis. Methods: A total of 569 cases which were diagnosed with positive soft markers in the department of gynecology and obstetrics of the Second Hospital of Jilin University from Jan.2016 to Jan.2017 were studied by ultrasonography. Twenty-five cases were lost in follow-up and finally 544 cases were included as group A. Those fetuses who combined with other malformations were induced labor. Non-invasive DNA examination was recommended for continued pregnant women, and those pregnant women whose results were high risk underwent the amniotic cavity puncture. When the fetal aneuploidy was confirmed, they chose induced labor. We followed the rest of those patients until postnatal half year. Randomly selected 544 cases during 16-18 weeks of pregnancy without obvious abnormalities into group B, followed up to half a year after birth. Results: In group A, 7 of the 544 cases were combined with other severe malformation in the beginning, among the remaining 537 patients, 273 of them received non-invasive DNA examination. Ten cases were high risk results, all of them underwent the amniotic cavity puncture with the result of chromosome abnormality, and they chose induced labor. Six cases were found other malformation in the second trimester who chose induced labor, and the rest 521 cases followed until the fetuses was born after half year had a favorable prognosis. In group B, 1 cases of severe deformities and 1 cases of haploid fetuses were found in 544 fetuses. The incidence of haploid fetus in group A and group B were 1.8% and 0.2%, respectively, with statistically significant (P<0.05). The incidence of severe malformation in group A and group B were 2.3% and 0.2%, respectively, with statistically significant (P<0.05). Conclusions: During 16-18 weeks of pregnancy, sonographic markers may indicate an increased risk in fetal chromosomal abnormalities. The risk of serious malformation was increased in the fetuses with ultrasonic soft marker positive, but there was no specificity.

[Evaluation of pelvic floor function of postpartum pelvic floor ultrasound in pregnant women with multiple pregnancies].

Objective: To probe the effect of multiple pregnancy on pelvic floor function of pregnant women, Pelvic floor ultrasonography was performed on the 42 day postpartum women.And the bladder neck mobility, bladder and urethral posterior angle and pelvic diaphragmatic hiatus area were measured. Methods: Collect 200 cases 42 day postpartum women who visited the second hospital of Jilin University from July 2015 to June 2017, of which 100 cases of primipara belong to group A, 100 cases of multiple pregnancy belong to group B, and 100 cases without maternal at the same age belong to the control group, ultrasound measurement of the bladder neck mobility, bladder and urethral posterior angle and pelvic diaphragmatic hiatus area were measured.t test were proformed respectively between the three groups, P<0.05 was considered statistically significant difference. Results: In the control group, the bladder neck mobility is (2.59±0.51) cm , the bladder neck mobility in A group is (2.99±0.69) cm, the bladder neck mobility in B group is (3.36±0.71) cm; the bladder and urethral posterior angle in the control group is (112.56±13.61)°, the bladder and urethral posterior angle in the control group after Valsalva action angle is(135.37±12.17)°, the bladder and urethral posterior angle in A group is(119.26±15.80)°, the bladder and urethral posterior angle in group A after Valsalva action is(141.79±12.08)°, the bladder and urethral posterior angle in B group is(123.62±16.20)°, the bladder and urethral posterior angle in group B after Valsalva action is (148.92±13.60)°; the pelvic diaphragmatic hiatus area in the control group is (13.35±2.86) cm(2,) the pelvic diaphragmatic hiatus area in the control group after Valsalva action is(15.28±3.15) cm(2,) the pelvic diaphragmatic hiatus area in A group is(17.52±3.19) cm(2,) the pelvic diaphragmatic hiatus area in A group ater Valsalva action is (18.06±5.13_the pelvic diaphragmatic hiatus area) cm(2,) the pelvic diaphragmatic hiatus area in B group is (18.26±4.18) cm(2,) the pelvic diaphragmatic hiatus area in B group after Valsalva action is (20.3±3.53) cm(2).In group A, group B and the control group, the measured value of the bladder neck mobility, bladder and urethral posterior angle and pelvic diaphragmatic hiatus area were examined by t test, and P<0.05, which means the difference was statistically significant. Conclusion: Pregnancy can affect the function of female pelvic floor, and the effect of parturient is more significant than that of the primipara.

Comparison of two series of non-invasive instruments used for the skin physiological properties measurements: the DermaLab® from Cortex Technology vs. the series of detectors from Courage & Khazaka.

BACKGROUND/PURPOSE: The detectors from Courage & Khazaka and DermaLab® from Cortex Technology were two series of the most commonly used non-invasive instruments for the skin physiological properties measurements. The aim of this study is to reveal the differences and correlations in measuring skin color, hydration, transepidermal water loss (TEWL), sebum and elasticity on the forearm or faces between two commercially available series of instruments. METHODS: 30 subjects were enrolled to be measured by the two series of instruments. The measurements by each series were performed on the left/right side of the body randomly. The hydration, sebum, elasticity and TEWL measurements were performed on different sites. RESULTS: Positive correlations were found in the values of skin color, hydration, TEWL, sebum and visco-elasticity detected by the two series. The values related to skin firmness measured by the two instruments were statistically negative correlated. Contrary to the results in measuring the skin color, the detectors from Courage & Khazaka presented lower values of variation in measuring skin hydration and TEWL than those from DermaLab® . CONCLUSION: The two series have significant correlations.The differences of the two series can be due either to differences in the design of the probe or left/right part of the body.

[The Study of relationship between fetal radius loss and chromosomal abnormality].

Objective: To explore the relationship between fetal radius loss and chromosomal abnormalities. Methods: Collect data of 3 100 cases pregnant women who had been checked in the second hospital of Jilin University from 2012 to 2015.There were 8 cases of absent radius, except 1 case of fetal lost follow-up, the remaining 7 cases had complete ultrasound, chromosome examination and the result of induction.The relationship between fetal radius loss and chromosomal abnormalities were analysed. Results: There were 1 case of 21 trisomy syndrome, 1 case of trisomy 13 syndrome, 2 cases of trisomy 18, 2 cases of chromosome translocation, 1 case of normal chromosome result and 1 case was lost to follow-up of the 8 absent radius fetuses. Conclusion: Through a comparison between the chromosome and ultrasonic characteristics of fetuses who have absent radius, we had indicated the relationship of fetal radius deletion and chromosomal anomaly, improved the positive rate of chromosome invasion examination, and provided the reference for eugenics.

Effect of polychlorinated biphenyls on oxidation stress in the liver of juvenile GIFT, Oreochromis niloticus.

The present study clearly showed that chronic exposure to polychlorinated biphenyls (PCBs) at environmentally relevant concentrations can damage juvenile tilapia livers by modulating antioxidant enzyme activities and gene transcription, which affects toxic bioaccumulation and histological congestion. The results suggest that PCBs caused a decrease in the activity of some hepatic antioxidative and biotransformation enzymes (SOD, CAT, GST, T-GSH, and MDA) in tilapia at 7 days, as well as transcriptional changes (sod, cat, and gst). Except for some antioxidant parameters (T-GSH, GSH/GSSG, T-AOC, and MDA), significant declines and increases occurred at 14 and 21 days, respectively. Most of the antioxidant enzymatic signatures and genotoxicity significantly increased at 14 and 21 days. This study presented evidence that PCBs could result in hepatic toxicity through oxidative stress in the early growth stages of tilapia, and we speculated that oxidative stress plays an important role in embryonic developmental toxicity induced by PCBs.

[Prenatal ultrasound diagnosis, prognosis and chromosome analysis of fetal bowel dilatation].

Objective: To investigate the relationship among the prenatal ultrasound, prognosis and chromosome results of fetal bowel dilatation. And in order to further improve the positive rate of prenatal chromosome examination operation, and reduce the risk of missed diagnosis. Methods: Ninety fetuses who were diagnosed as fetal bowel dilatation by prenatal ultrasound from June 2013 to December 2015 in the Second hospital of Jilin University were enrolled. Chromosomes were examined by amniotic cavity puncture or umbilical cord blood puncture. The change of fetus's bowel was monitored periodically by prenatal ultrasound. The normal bowel movement of newborns was a good prognosis. The abdominal X ray or barium contrast radiography was performed in the newborns who did not have normal bowel movement after delivery. Patients underwent surgery or conservative treatment after diagnosis. Fetal karyotype analysis of aborted fetus was carried out by amniotic cavity puncture and umbilical cord blood before induction of labor. Autopsy was performed after induced labor. Patients who were not continued examination in our hospital were followed up by telephone. Results: Among the 90 fetuses, there are 11 cases of duodenum dilatation, 38 cases of jejunum and ileum dilatation, 41 cases of colorectal dilatation. Ten cases of duodenum dilatation were confirmed by autopsy after induced labor, and one case was lost in follow-up. Chromosome examination revealed 3 cases of 21- three body syndrome, 1 case of 18- three body syndrome, 1 case of chromosomal translocation. In 38 cases of jejunum and ileum dilatation, bowel dilatation of 26 cases had decrease or no obvious increase with good prognosis. Six cases of induced labor, 3 cases of receive surgery after birth, 2 cases of postoperative survival, and 3 cases of loss of follow-up. Chromosome examination revealed 1 case of 21- three body syndrome and 1 case of chromosomal translocation. In 41 cases of colorectal dilatation, 29 cases had good prognosis. Five cases were aborted, 1 case of fetal death, 2 cases died within 1 month after birth, 2 cases received surgery after birth and survived after operation, and 2 cases of loss of follow-up. Conclusions: Clinical prognosis and the associated risk of chromosome abnormalities in patients with fetal bowel dilatation are different in terms of its expansion location and extent of the different, which need to a specific analysis of specific situations.

[Security of hormone replacement therapy among postoperative patients with endometrial carcinoma: a Meta-analysis].

OBJECTIVE: To systematically evaluate the security of hormone replacement therapy (HRT) among postoperative patients with endometrial carcinoma (EC). METHODS: A systematic review and Meta-analysis of studies on security of HRT among EC patients after operation was done by Revman 5.2 software. Studies were mainly searched from the CENTRAL, Medline, Embase, Ovid, Wanfang, CNKI databases. RESULTS: A total of 7 studies with 2 038 stageⅠand stageⅡ endometrial carcinoma patients were included. The quality of 6 studies included were medium, and 1 study was high. The endometrial carcinoma patients on HRT did not have a statistically increased incidence in the EC recurrence (RR=0.69, 95%CI (0.42-1.15), P=0.16) and cancer-induced death (RR=0.55, 95%CI (0.25-1.21), P=0.14). Subgroup analysis for the start of HRT within 6 months from time of surgery group and only estrogen replacement therapy group found no statistical different in the risk of the EC recurrence and cancer-induced death, compared with control group. No statistically increased risk of the EC recurrence was observed for estrogen plus progestin replacement therapy group. CONCLUSION: There is no statistical difference in the recurrence rate and cancer-induced death rate of EC whether the early stage postoperative patients used HRT or not.

Expression and functional role of long non-coding RNA AFAP1-AS1 in ovarian cancer.

OBJECTIVE: The present study aimed to determine the expression, roles and functional mechanisms of long non-coding RNA AFAP1-AS1 (AFAP1-AS1) in the progression of ovarian cancer. PATIENTS AND METHODS: AFAP1-AS1 expression was assessed in ovarian cancer samples and ovarian cancer cell lines by quantitative real-time PCR. The association of AFAP1-AS1 expression with clinicopathological factors was also analyzed. Gain-/loss-of-function studies were performed to investigate the expression pattern and functional role of AFAP1-AS1 in ovarian cancer. Effects of AFAP1-AS1 on cell proliferation were studied using cell-counting kit-8 assay. The effect of AFAP1-AS1 on ovarian cancer cells apoptosis was assessed by flow cytometry assay. RESULTS: AFAP1-AS1 was highly expressed both in ovarian cancer samples and cell lines compared with their corresponding normal counterparts. High AFAP1-AS1 expression was significantly associated with response and FIGO stage. Gain-of-function and loss-of-function experiments showed that AFAP1-AS1 promoted ovarian cancer cells proliferation. Flow cytometry assay showed that knockdown of AFAP1-AS1 promoted ovarian cancer cells apoptosis. CONCLUSIONS: Our results suggested that AFAP1-AS1 might be considered as a novel oncogene involved in ovarian cancer progression.

Correlation between polymorphism of platelet alloantigen genes HPA-1-5 and type 2 diabetes complication by carotid atherosclerosis in a Chinese population.

We investigated the association between the polymorphism of human platelet alloantigen genes HPA-1-HPA-5 and the complication of type 2 diabetes mellitus (T2DM) by carotid atherosclerosis (CA) among Han people in Guiyang District, China. Ninety-nine T2DM patients were selected from the Affiliated Hospital of Guiyang Medical College and divided into a CA(+) group and a CA(-) group. A control group comprised 100 healthy people from the medical examination center of the same hospital. Genomic DNA from all the subjects was isolated by phenol-chloroform extraction and target genes were amplified using sequence-specific primer-polymerase chain reaction, followed by gene type detection of HPA. There were significant differences in allele and genotype frequencies of HPA-1, -2, -3, and -5 among the three groups [CA(+), CA(-), and the control group] (P < 0.05), and significant differences in allele and genotype frequencies of HPA-1, -2, and -3 between groups CA(+) and CA(-) and the control group (P < 0.05). Moreover, there was a significant difference in allele and genotype frequencies of HPA-5 between the CA(+) and CA(-) groups (P < 0.05). Logistic regression analysis showed that risk factors for T2DM patients developing a CA complication were age, duration of diabetes, high blood pressure, smoking, overweight, abnormal blood lipid levels, and polymorphism of HPA-5. There may be a correlation between T2DM and polymorphism of HPA-1-3. Polymorphism of HPA- 5 is probably a risk factor for CA complicating T2DM.

Abnormality of bone marrow-derived mesenchymal stem cells in patients with systemic lupus erythematosus.

Bone marrow-derived mesenchymal stem cells (MSCs) are key components of the hematopoietic microenvironment and provide support to hematopoiesis and modulate immune system. Several studies suggest that SLE may be seen as stem cell disorders. However, it is unclear that whether MSCs from SLE patients are defective. So in this research, we studied the biological character of bone marrow derived MSCs in patients with SLE, focused on their phenotype (morphology and immunophenotype), karyotype, cytokines expression and hematopoietic support of MSCs. Our results showed that MSCs from SLE patients and normal controls can be successfully culture-expanded, but the MSCs from SLE grew more slowly than those of normal controls (P < 0.05). Cells from both groups were positive for CD29, CD44 and CD105, and negative for CD14, CD34, CD45 and HLA-DR. MSCs from SLE have a normal karyotype. Both groups express IL-6, IL7, IL-11, macrophage colony stimulating factor (M-CSF) and stem cell factor (SCF) at mRNA level. While IL-6 and IL-7 were down-regulated in MSCs from SLE patient (P < 0.05) at mRNA level. The MSCs from SLE patients and normal controls were infused into ICR (Tac: Icr: Ha strain) mice after high-dose chemotherapy, with no adverse events in either group. Recovery of white blood cells, hemoglobin and platelet was more rapid (P < 0.05) compared with the group without MSCs infusion. We conclude that MSCs in patient with SLE have abnormalities compared with those in normal control. MSCs in patient with SLE may play an important role in the SLE pathogenesis.

Triterpenoid glycoside from Cimicifuga racemosa.

One new triterpene glycoside, cimiracemoside , and 14 known triterpene glycosides have been isolated from the rhizome extracts of black cohosh (Cimicifuga racemosa). On the basis of spectral and chemical evidence, the structure of the new compound was elucidated to be 12beta-acetoxycimigenol-3-O-beta-D-xylopranoside, and the known compounds were identified to be 25-acetylcimigenol xyloside, cimigenol-3-O-beta-D-xylopyranoside, acetin, 27-deoxyacetin, cimicifugoside H-1, 23-O-acetylshengmanol 3-O-beta-D-xylopranoside, foetidinol-3-O-beta-xyloside, cimicifugoside H-2, 25-O-methylcimigenol xyloside, 21-hydroxycimigenol-3-O-beta-D-xylopyranoside, 24-epi-7,8-didehydrocimigenol-3-xyloside, cimidahurinine, cimidahurine and cimifugin. The compounds, , and showed weak antibacterial activities in the agar diffusion assay.

Media remodeling--the result of stent induced media necrosis and repair.

BACKGROUND: Stents have been introduced clinically to help maintaining the patency of the vascular lumen after balloon angioplasty. To ensure a sufficient lumen of the stented vessel, oversized stents are frequently used. However especially deployment of oversized stents may lead to mechanical injury of the intima and media of the vessel wall. The aim of the study was to characterize the vascular lesions and repair processes within the first 4 weeks after implantation of oversized stents in the rabbit carotid artery and thereby contribute to the understanding of vascular remodeling during stent implantation. METHODS: Oversized stents were implanted in the carotid artery of Chinchilla rabbits. Rabbits were sacrificed 3, 7, 14, and 28 days after stent implantation and a detailed histologic and immunohistochemical analysis was performed. RESULTS: The carotid artery was expanded by a factor of 1.3-1.5, leading to a constant dilatation of the vessel. The struts were deeply impressed in the vessel wall, resulting in a disruption of the intima, thrombus formation, media compression and segmental media necrosis. The necrotic media was repopulated by smooth muscle cells by day 7. In contrast to the intima lesions, necrotic areas of the media were not invaded by an inflammatory infiltrate. Formation of neointima, characterized by a confluent layer of endothelial cells and deposition collagenfibers started in close vicinity of the struts. CONCLUSIONS: Being part of a high-pressure system, the arterial vessel apparently adapts to constant dilatation. Deployment of oversized stents caused intima disruption, media necrosis of varying degree and constant dilatation of the vessel wall. Necrosis and repopulation of smooth muscle cells of the media took place within the first 4 weeks, leading to the speculation whether the repopulating SMC are more resistant to the constant pressure.

Outward K+ channels in Brassica chinensis pollen protoplasts are regulated by external and internal pH.

Patch-clamp whole-cell and single-channel recording techniques were used to investigate the regulation of outward K(+) channels by external and internal protons in Brassica chinensispollen protoplasts. Outward K(+) currents and conductance were insensitive to external pH (pH(o)) except at pH 4.5. Maximal conductance (G(max)) for the outward K(+) currents was inhibited at acidic external pH. Half-activation voltage ( E(1/2)) for the outward K(+) currents shifted to more positive voltages along with the decrease in pH(o). E(1/2) can be described by a modified Henderson-Hasselbalch equation expected from a single titratable binding site. The activation kinetics of the outward K(+) channels was largely insensitive to pH(o). An internal pH (pH(i)) of 4.5 significantly increased outward K(+) currents and conductance. G(max) for the outward K(+) currents decreased with elevations in pH(i). In contrast to the effect of pH(o), E(1/2) was shifted to more positive voltages with elevations in pH(i). The outward K(+) currents, G(max) and E(1/2) can be described by the modified Henderson-Hasselbalch equation. Furthermore, acidifying pH(i) accelerated the activation of the outward K(+) currents significantly. The differences in electro-physiological properties among previously reported and currently described plant outward K(+) channels may reflect differences in the structure of these channels.

In vitro Arabidopsis pollen germination and characterization of the inward potassium currents in Arabidopsis pollen grain protoplasts.

The focus of this study is to investigate the regulatory role of K(+) influx in Arabidopsis pollen germination and pollen tube growth. Using agar-containing media, in vitro methods for Arabidopsis pollen germination have been successfully established for the first time. The pollen germination percentage was nearly 75% and the average pollen tube length reached 135 microm after a 6 h incubation. A decrease in external K(+) concentration from 1 mM to 35 microM resulted in 30% inhibition of pollen germination and 40% inhibition of pollen tube growth. An increase in external K(+) concentration from 1 mM to 30 mM stimulated pollen tube growth but inhibited pollen germination. To study how K(+) influx is associated with pollen germination and tube growth, regulation of the inward K(+) channels in the pollen plasma membrane was investigated by conducting patch-clamp whole-cell recording with pollen protoplasts. K(+) currents were first identified in Arabidopsis pollen protoplasts. The inward K(+) currents were insensitive to changes in cytoplasmic Ca(2+) but were inhibited by a high concentration of external Ca(2+). A decrease of external Ca(2+) concentration from 10 mM (control) to 1 mM had no significant effect on the inward K(+) currents, while an increase of external Ca(2+) concentration from 10 mM to 50 mM inhibited the inward K(+) currents by 46%. Changes in external pH significantly affected the magnitude, conductance, voltage-independent maximal conductance, and activation kinetics of the inward K(+) currents. The physiological importance of potassium influx mediated by the inward K(+)-channels during Arabidopsis pollen germination and tube growth is discussed.

Identification and characterization of the inward K+ channel in the plasma membrane of Brassica pollen protoplasts.

Patch clamp techniques have been used to identify and characterize the whole-cell currents carried by inward K+ channels in isolated matured pollen protoplasts of Brassica chinensis var. chinensis. The whole-cell inward currents in the isolated pollen protoplasts were activated at hyperpolarized membrane potentials more negative than -100 mV. The magnitudes of the whole-cell inward currents were strongly dependent on the external K+ concentration, and were highly selective for K+ over other monovalent cations. The inward currents were not observed when external K+ was replaced with the same concentration of Cs+ or Na+. The addition of 1 mM or 10 mM Ba2+ in external solutions resulted in 30% or 80% inhibition of the inward currents at -180 mV, respectively. These results demonstrated that the inward K+ currents mainly account for the recorded whole-cell inward currents in Brassica pollen protoplasts. Increase of cytoplasmic Ca2+ concentrations from 10 nM to 30 microM or even 5 mM did not affect the inward K+ currents. Decrease of external Ca2+ concentrations from 10 mM to 1 mM inhibited the inward K+ currents by 25%, while the increase of external Ca2+ from 10 mM to 50 mM almost completely blocked the inward K+ currents. Physiological importance of K+ transport into pollen and its possible regulatory mechanisms are also discussed.