Increased Expression of Efflux Pump norA Drives the Rapid Evolutionary Trajectory from Tolerance to Resistance against Ciprofloxacin in Staphylococcus aureus.

The intensively intermittent use of antibiotics promotes the rapid evolution of tolerance, which may lead to resistance acquisition in the following evolutionary trajectory. In addition to directly exporting antibiotics as an instant resistance strategy, efflux pumps are overexpressed in tolerant strains. To investigate how efflux pumps participate in resistance development from tolerance to resistance, we performed in vitro evolutional experiments against the antibiotic ciprofloxacin in norA efflux pump mutants of Staphylococcus aureus. These experiments demonstrated that overexpression of norA rapidly facilitated the development of ciprofloxacin resistance from tolerance to resistance through elevated spontaneous mutations. The generated resistance mutations were further fixed in the population by increasing survival ability. The observed Ser80Phe and Glu84Lys mutations in the topoisomerase IV ParC (GrlA in S. aureus) may be responsible for tolerant strains to develop resistance to ciprofloxacin since it has been reported that such mutations disrupt the water-metal ion bridge between quinolones and ParC. MepA and Sav1866 are related to the same antibiotic (ciprofloxacin) susceptibility as NorA, and they also contributed to resistance development against ciprofloxacin. MgrA positively regulated NorA expression and the development of ciprofloxacin resistance. Importantly, blocking the evolutionary pathway by coadministering ciprofloxacin with the efflux pump inhibitor reserpine effectively delayed the resistance acquisition in an in vitro experiment. This study illustrated the role of efflux pumps in the evolutionary trajectory from tolerance to resistance. The delayed resistance development caused by the efflux pump inhibitor illuminates a possible strategy for postponing the resistance acquisition from tolerance to resistance by disrupting efflux pumps.

Recommendations for the management of advanced and metastatic renal cell carcinoma: joint consensus statements from the Hong Kong Urological Association and the Hong Kong Society of Uro-Oncology.

INTRODUCTION: Kidney cancer, primarily renal cell carcinoma (RCC), ranks among the top 10 most common malignancies in the male population of Hong Kong. In 2019, members of two medical societies in Hong Kong formed an expert panel to establish a set of consensus statements for the management of metastatic RCC. On 22 June 2021, the same panel met to review recent evidence and reassess their positions regarding the management of advanced and metastatic RCC, with the aim of providing recommendations for physicians in Hong Kong. PARTICIPANTS: The panel included 12 experts (6 clinical oncologists and 6 urologists) who had extensive experience managing patients with RCC in Hong Kong. EVIDENCE: The panel reviewed randomised controlled trials, observational studies, systematic reviews/meta-analyses, and international clinical guidelines to address key clinical questions that were identified before the meeting. CONSENSUS PROCESS: In total, 15 key clinical questions were identified before the meeting, covering the surgical and systemic treatment of advanced or metastatic clear cell, sarcomatoid, and non-clear cell RCCs. At the meeting, the panellists voted on these questions, then discussed relevant evidence and practical considerations. CONCLUSIONS: The treatment landscape for advanced and metastatic RCC continues to evolve. More immune checkpoint inhibitor (ICI)-based combination regimens will be indicated for the treatment of metastatic clear cell RCC. There is increasing evidence concerning the benefit of adjuvant ICI treatment for resected advanced RCC. This article summarises recent evidence and expert insights regarding a series of key clinical questions about the management of advanced and metastatic RCC.

[The clinical effect of ultrasonic bone curette-assisted "zoning" style laminectomy for the treatment of severe ossification of thoracic ligamentum flavum].

Objective: To investigate the safety and clinical efficacy of "zoning" style laminectomy by ultrasonic bone curette in patients with severe thoracic ossification of the ligamentum flavum(TOLF). Methods: The clinical data of 36 patients with severe TOLF treated by "zoning" style laminectomy at Department of Spinal Surgery,Zhengzhou Orthopaedic Hospital from October 2015 to October 2018 were respectively analyzed.There were 17 males and 19 females,aged(57.3±10.2)years(range:43 to 80 years).According to the anatomical characteristics of the thoracic ligamentum flavum and the pathological process of ossionization,each decompression segment was divided into the upper 1/3 area of the lamina,the bilateral area of the ossionum flavum,the transitional area,and the area of close contact between the ossionum flavum and the spinal cord.Different surgical strategies were used for decompression in turn.The modified Japanese Orthopedic Association (mJOA) was used to evaluate the neurological function status before and after surgery,to evaluate the surgical effect of patients,and to observe the surgical complications.Paired sample T test was used for data analysis. Results: All 36 patients successfully completed the operation,the operation time was (88.6±24.6) minutes(range:60 to 150 minutes).The intraoperative blood loss was (426.7±167.4) ml(range:250 to 800 ml).Follow-up time was (27.2±7.7) months(range:12 to 48 months).The mJOA score at the last follow-up was 9.0±1.5,which was statistically significant compared with the preoperative score 5.4±1.8 (t=13.59,P<0.01).The improvement rate of mJOA score was (65.7±22.1) %,of which 17 cases were excellent (47.2%),13 cases were good (36.1%),4 cases were normal (11.1%),2 cases were ineffective (5.6%).Ten patients had cerebrospinal fluid leakage during the separation or removal of dural ossification and were cured after a series of comprehensive conservative treatment.Two patients showed transient neurological deterioration,and the neurological function gradually recovered to the preoperative state after comprehensive treatment such as increasing the mean arterial pressure and using neurotrophic drugs.During the follow-up,no aggravation of neurological dysfunction and segmental kyphosis were found. Conclusions: The ultrasonic bone curette-assisted "zoning" style laminectomy for the treatment of severe TOLF can directly observed the position relationship between ossification of the ligamentum flavum and the spinal canal structure during the operation,and accurately guide the surgical decompression.It has the advantages of safe operation and complete decompression,which provides an important reference for the selection of clinical surgery.

[The past, present and future of the control of axial alignment of the lower extremity in high tibial osteotomy].

High tibial osteotomy(HTO) is an effective method for the treatment of knee osteoarthritis by transferring the weight bearing line to the lateral tibial plateau, which can significantly reduce the pressure and cartilage lesion of medial knee compartment.However, under- and over-correction of weight bearing line can lead to early postoperative failure.It is necessary to define the standard of axis correction, make correct preoperative plan, ensure the accuracy of operation and consider the risk factors of under- and over-correction of axis.With the advent of the era of intelligent medicine, the application of patient-specific instrumentation technology based on three dimention printing and navigation technology will help to achieve the precise control of axial alignment in high tibial osteotomy.

Population dynamics of hepatitis C virus subtypes in injecting drug users on methadone maintenance treatment in China associated with economic and health reform.

The extensive genetic heterogeneity of hepatitis C virus (HCV) requires in-depth understanding of the population dynamics of different viral subtypes for more effective control of epidemic outbreaks. We analysed HCV sequences data from 125 participants in Wuhan, China. These participants were newly infected by subtype 1b (n=13), 3a (n=15), 3b (n=50) and 6a (n=39) while on methadone maintenance treatment (MMT). Bayesian phylogenies and demographic histories were inferred for these subtypes. Participants infected with HCV-1b and 3a were clustered in well-supported monophyletic clades, indicating local subepidemics. Subtypes 3b and 6a strains were intermixed with other Chinese isolates, as well as isolates from other Asian countries, reflecting ongoing across geographic boundary transmissions. Subtypes 1b and 3a declined continuously during the past ten years, consistent with the health and economic reform in China, while subtype 3b showed ongoing exponential growth and 6a was characterized by several epidemic waves, possibly related to the recently growing number of travellers between China and other Asian countries. In conclusion, results of this study suggest that HCV subtype 3b and 6a subepidemics in China are currently not under control, and new epidemic waves may emerge given the rapid increase in international travelling following substantial economic growth.

[Willingness and influencing factors of using pre-exposure prophylaxis among 301 men have sex with men in Wuhan city, 2015].

Objective: To understand willingness and influencing factors of using pre-exposure prophylaxis (Pr-EP) among men who have sex with men (MSM). Methods: Snow ball sampling was employed to recruit MSM in the social spaces (like bars and bathrooms) with focused activities by MSM and internet (QQ and Wechat) in Wuhan between August and November, 2015. 304 MSM were considered eligible when they were self-identified MSM and has had sex with men in the previous 12 months, over the age of 18 and have full civil liability. On-site and online questionnaire surveys were conducted by self-designed questionnaires to collect information including demographic characteristics, sexual risks and practices, awareness of PrEP, and willingness to use PrEP. A total of 301 qualified questionnaires were obtained. Multivariate logistic regression models were constructed to identify factors associated with willingness to use Pr-EP. Results: The mean age of surveyed MSM were (27.51±8.31) years, between18-61. 149 on-site survey, online were152; 131 MSM have regular homosexual partners, 170 MSM have not regular homosexual partners. Only 17.28% (52/301) had heard of Pr-EP before this survey, 18.32% (24/130) had heard of Pr-EP among those who had regular homosexual partners and those who had not accounted for 16.47% (28/170). 74.42% (224/301) had willingness to use Pr-EP after they knew Pr-EP was safe and effective through the survey. The proportion among those who had regular homosexual partners was 74.05%(74), and the proportion among those who had not was 74.71% (127); Among those who had regular homosexual partners, results suggested that those who were married/cohabiting were more likely to report a willingness to use PrEP compared to unmarried/divorced or widowed (OR=5.60), compared with homosexual, heterosexuality was associated with decreased odds of willingness to use Pr-EP (OR= 0.22), compared with HIV status of sexual partner was negative or uncertain, positive infection status was associated with increased odds of willingness to use (OR=7.52). Compared with MSM who have not regular homosexual partners, those who were married/cohabiting were more likely to report a willingness to use PrEP compared to unmarried/divorced or widowed (OR=9.09), compared with those who think they have risk of infection, those who do not think they have risk of infection was associated with decreased odds of willingness to use Pr-EP (OR= 0.30), compared with those with a high frequency to seek sexual partners, those not often to seek was associated with decreased odds of willingness to use Pr-EP (OR= 0.27). All above P values were<0.05. Conclusion: The awareness rate of Pr-EP among MSM in Wuhan is low in 2015, but the willingness to use Pr-EP could get a considerable increase after introduction. It is considered that promotion of Pr-EP is feasible in China, and there are different influencing factors for the willingness between two MSM subgroups (having regular homosexual partners and having no regular homosexual partners).

[Impact of symptom onset to first medical contact time on the prognosis of patients with acute ST-segment elevation myocardial infarction].

Objective: To investigate the impact of symptom onset to first medical contact (SO-to-FMC)time on the prognosis of patients with acute ST-segment elevation myocardial infarction(STEMI). Methods: The clinical data of 341 consecutive STEMI patients, who were hospitalized to our hospital and received primary percutaneous coronary intervention(PCI) from August 2011 to April 2016, were retrospectively analyzed. The patients were divided into ≤90 min group (201 cases) and >90 min group (140 cases) according to the SO-to-FMC time. The treatment time, mortality and incidence of major adverse cardiac and cerebro-vascular events(MACCE) were analyzed. The risk factor of 1-year mortality after PCI and 1-year incidence of MACCE during the post-discharge follow-up period were analyzed by binary logistic regression analysis. The predictor of 4.5-year mortality after PCI was analyzed by multivariate Cox regression analysis. Methods The door to balloon time (104(88, 125) min vs. 111(92, 144)min, P=0.023), first medical contact to balloon time(146(119, 197) min vs. 177(125, 237)min, P=0.005), and symptom onset-to-balloon time(200(170, 257) min vs. 338(270, 474)min, P<0.001)were all significantly shorter in the ≤90 min group than in>90 min group. The 30-day mortality (2.99% (6/201) vs. 7.86%(11/140), P=0.042), 1-year mortality (2.89 (5/173) vs. 9.57(11/115), P=0.015), 1-year incidence of MACCE during the post-discharge follow-up period(1.16%(2/173) vs. 6.96%(8/115), P=0.021), and 4.5-year cumulative mortality(3.00% vs. 11.20%, P=0.007) after PCI were significantly lower in the ≤90 min group than in the >90 min group. Moreover, the 4.5-year incidence with free of MACCE (97.20% vs. 88.80%, P=0.025) during the post-discharge follow-up period was significantly higher in the ≤90 min group than in the >90 min group. In-hospital mortality was similar between the two groups (2.49%(5/201) vs. 6.43%(9/140), P=0.071). Results: The door to balloon time (104(88, 125) min vs. 111(92, 144)min, P=0.023) , first medical contact to balloon time(146(119, 197) min vs. 177(125, 237)min, P=0.005), and symptom onset-to-balloon time(200(170, 257) min vs. 338(270, 474)min, P<0.001) were all significantly shorter in the ≤90 min group than in >90 min group. The 30-day mortality(2.99% (6/201) vs. 7.86%(11/140), P=0.042), 1-year mortality (2.89(5/173) vs. 9.57(11/115), P=0.015), 1-year incidence of MACCE during the post-discharge follow-up period (1.16%(2/173) vs. 6.96%(8/115), P=0.021), and 4.5-year cumulative mortality (3.00% vs. 11.20%, P=0.007) after PCI were significantly lower in the ≤90 min group than in the >90 min group. Moreover, the 4.5-year incidence with free of MACCE (97.20% vs. 88.80%, P=0.025) during the post-discharge follow-up period was significantly higher in the ≤90 min group than in the >90 min group. In-hospital mortality was similar between the two groups (2.49%(5/201) vs. 6.43%(9/140), P=0.071). Results of binary logistic regression analysis showed that the SO-to-FMC time >90 min was the risk factor of 1-year mortality(OR=2.90, 95%CI 1.22-6.92, P=0.016) and 1-year incidence of MACCE (OR=5.19, 95%CI 1.21-22.20, P=0.026) during the post-discharge follow-up period. Multivariate Cox regression analysis demonstrated that the SO-to-FMC time >90 min was the risk factor of 4.5-year mortality after PCI in patients with STEMI (HR=2.88, 95%CI 1.10-7.53, P=0.031). Conclusion: Shorting the SO-to-FMC time can significantly reduce the treatment time of STEMI patients, short and long-term mortalities and the incidence of MACCE, and improve the prognosis of patients with STEMI.

Religiosity and ethical ideology of physicians: a cross-cultural study.

In this study of ethical ideology and religiosity, 1,255 physicians from Canada, China, Ireland, India, Japan and Thailand participated. Forsyth's (1980) Ethical Position Questionnaire and Rohrbaugh and Jessor's (J Pers 43:136-155, 1975) Religiosity Measure were used as the survey instruments. The results demonstrated that physicians from India, Thailand and China reported significantly higher rates of idealism than physicians from Canada and Japan. India, Thailand and China also scored significantly higher than Ireland. Physicians from Japan and India reported significantly higher rates of relativism than physicians from Canada, Ireland, Thailand and China. Physicians from China also reported higher rates of relativism than physicians from Canada, Ireland and Thailand. Overall, religiosity was positively associated with idealism and negatively associated with relativism. This study is the first to explore the differences between ethical ideology and religiosity among physicians in an international setting as well as the relationship between these two constructs. Both religiosity and ethical ideology are extremely generalized, and the extent to which they may impact the actual professional behaviour of physicians is unknown. This paper sets up a point of departure for future research that could investigate the extent to which physicians actually employ their religious and/or ethical orientation to solve ambiguous medical decisions.

Erdheim-Chester disease: an uncommon cause of upper urinary tract obstruction.

Erdheim-Chester disease is a rare non-Langerhans form of systemic histiocytosis of unknown origin. We describe a 45-year-old man presenting with bilateral hydronephrosis suggestive of extrinsic urinary tract obstruction. Computed tomography revealed extensive hypodense soft tissue infiltration in the retroperitoneum surrounding the kidneys. Needle biopsy of the retroperitoneal soft tissue revealed aggregates of lipid-laden histiocytes expressing CD68 but negative for CD1a and S100 protein. The diagnosis of Erdheim-Chester disease was supported by typical radionuclide bone scinitigraphic findings. Treatment with prednisolone, sirolimus, and regular ureteric stent revision was initiated to achieve adequate urinary tract drainage. To our knowledge, this is the second patient with Erdheim-Chester disease reported in Hong Kong. A high index of suspicion is required to avoid delay in the diagnosis of this rare disease.

[Misdiagnosis analysis: 120 patients with nasal extranodal NK/T cell lymphoma in head and neck].

Objective:The Clinicopathological characteristics and the reason of misdiagnosis about nasal extranodal NK/T cell lymphoma in head and neck（ENKTL） are analysised to raise awareness and reduce misdiagnosis. Method:One hundred and twenty patients with ENKTL, diagnosed pathologically in head and neck from May 2010 to April 2018, were analyzed retrospectively. All cases were divided into misdiagnosed group and non-misdiagnosed group according to whether there were misdiagnosis and mistreatment before diagnosis. The differences of clinicopathological characteristics between the two groups before and after diagnosis were compared. The differences of overall survival（OS） between the two groups after treatment were also compared. Result:The misdiagnosis rate of this study was 71.7%, and they were misdiagnosed as sinusitis, nasal polyps, upper respiratory tract infection and so on. On the whole, the 1-year OS, 3-year OS and 5-year OS were 77.8%, 65.9% and 49.3% respectively. There was no significant difference in sex, age, first symptom, initial site, B symptom, superficial lymph node enlargement and weight loss between two groups before diagnosis（P>0.05）, however, there were significant differences in relative specific signs, hospital grade and time from first visit to definite diagnosis（P<0.05）. The proportion of the high-level hospitals in the first visit hospital was significantly lower than that in the non-misdiagnosed group, while the time from the first visit to the final diagnosis was significantly longer than that in the non-misdiagnosed group. There was no significant difference in international prognostic index（IPI） score, expression of Ki-67, therapeutic schedule, chemotherapy regimen for patients receiving chemotherapy, and radiation dose for patients receiving radiotherapy after diagnosis between the two groups（P>0.05）, but there was a significant difference in the clinical stages of Ann Arbor between the two groups（P<0.05）. The clinical staging of the misdiagnosed group was later than that of the non-misdiagnosed group. The 1-year OS, 3-year OS and 5-year OS were 73.6%, 59.3% and 43.2% in the misdiagnosed group respectively, and 88.2%, 82.4% and 64.2% in the non-misdiagnosed group respectively. The overall survival rate in the misdiagnosis group was lower than that in the non-misdiagnosed group, and the overall survival time was lower than that in the non-misdiagnosed group. However, there was no significant difference in the overall survival rates between the early stage（Ⅰ and Ⅱ） and the advanced stage（Ⅲ and Ⅳ） of Ann Arbor（P>0.05）. Conclusion:The non-specific clinical and the complexity of pathological features of ENKTL in head and neck might cause misdiagnosis, which leads to prolonged time from first visit to definite diagnosis, thus results in disease progression, and ultimately may lead to decreased overall survival rate. To avoid the misdiagnosis and early diagnosis is very important.

[COVID-19 pandemic: global epidemiological trends and China's subsequent preparedness and responses].

The outbreak of COVID-19 has spread quickly across 114 countries/territories/areas in six continents worldwide and has been announced as a pandemic by WHO. This study analyzed global COVID-19 epidemiological trends, examined impact of the pandemic on global health security, diplomacy, and social environment in China, and provided short- and long-term strategic policy recommendations for China's subsequent preparedness and responses.

A comparison of two rehabilitation protocols after simultaneous bilateral total knee arthroplasty: a controlled, randomized study.

Post-operative outcomes after simultaneous bilateral total knee arthroplasty in 115 patients randomly assigned to two rehabilitation protocols were compared. The traditional-protocol group performed a series of exercises on one leg and then repeated the same sequence on the other leg. The alternate-protocol group performed the same exercises, but alternated between legs with each individual repetition. Symptoms and function were assessed pre-operatively and at 1, 3, 6 and 12 months post-operatively. The alternate-protocol group had lower visual analogue pain scale scores in the early post-operative period, as well as higher Knee Society Scores and SF-12 physical and mental health summary scores after 1 and 3 months compared with the traditional-protocol group, but there were no differences between the two groups from 6 months post-operatively. There were no significant differences between the groups in terms of range of knee motion or incidence of deep vein thrombosis. The alternate-protocol for rehabilitation resulted in an early return to function and decreased pain levels following simultaneous bilateral total knee arthroplasty and was associated with the potential to produce more positive emotional states and earlier functional independence.

Baseline susceptibility of Cnaphalocrocis medinalis (Lepidoptera: Pyralidae) to Bacillus thuringiensis toxins in China.

Geographic variability in susceptibility of field-collected Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae) to Bacillus thuringiensis (Berliner) was studied to establish a geographic baseline for comparison of future population responses to the increased use of B. thuringiensis-based insect control products. Colonies of C. medinalis were established from 10 populations collected from 10 different provinces in the major rice (Oryza savita L.)-growing regions of China. Populations were evaluated for their susceptibility to Cry1Ac and Cry1Ab endotoxin proteins with the leaf-dip bioassay. The LC50 values to Cry1Ac and Cry1Ab were estimated for the 10 populations. Bioassay results indicated that the ranges of LC50 in the second instars of C. medinalis to Cry1Ac and Cry1Ab were from 3.77 to 208.22 mg ([AI])/liter and 0.22-7.05 mg ([AI])/liter, respectively. The relative ratios in susceptibility between the most susceptible and the most tolerant populations were beyond 50-fold for Cry1Ac and 30-fold for Cry1Ab. Moreover, there was a significant positive correlation between susceptibilities to the two toxins tested, suggesting that insect populations that are relatively tolerant to one protein are also relatively tolerant to the other.

[Comparison of age-based clinical and abnormal immune parameters in patients with Henoch-Schönlein purpura].

Objective: To explore age-based clinical and immune parameters in Henoch-Schönlein purpura (HSP) to determine clinically useful markers reflecting disease characteristic. Methods: A cohort of 502 patients with HSP were enrolled into this retrospective study to evaluate their clinical and immune data. Results: Majority HSP cases occurred at age ≤14 years and showed significant immune imbalances of ESR, CD3(+) cells, CD4(+) cells, CD3(-)CD16(+)CD56(+) cells, CD4(+)/CD8(+) cells, IgG, IgA, IgM, IgE, complements C3/C4 and ASO in the acute phase. Compared to patients aged >14 years, symptoms of joint were more frequent at disease onset in patients aged ≤14 years (20.8% vs 7.6%, χ(2)=13.547, P<0.001) , and involvement of digestive tract and joint were also more frequent (57.4% vs 33.8%, χ(2)=24.106, P<0.001; 55.9% vs 32.5%, χ(2)=23.768, P<0.001, respectively) , but not for involvement of kidney (21.4% vs 51.3%, χ(2)=42.440, P<0.001) . The patients aged ≤14 years had distinct immune state, reductions of CD3(+) cells, CD4(+) cells and IgG were more frequent than patients aged >14 years, also increase of ASO (33.1% vs 20.0%, χ(2)=6.656, P=0.010) , but not increase of IgA (2.6% vs 39.4%, χ(2)=15.582, P<0.001) . In addition, reduction of IgG and increase of IgE were positively associated with digestive tract involvement (P<0.001, P=0.001, respectively) , reduction of CD3(+)CD4(+) cells and normal IgM were positively associated with joint involvement (P=0.004, P=0.003, respectively) , increase of CD3(+)CD8(+) cells and normal CD3(+) cells were positively associated with kidney involvement (P=0.032, P=0.014, respectively) . Conclusion: HSP showed significant immune imbalance in the acute phase, patients between aged ≤14 and >14 years had distinct clinical and immune characteristic, and abnormal immune parameters were significantly associated with organ involvements.

Cowpoxvirus infection in the Patagonian cavy (Dolichotis patagonum) emerging disease in an educational animal park the first reported case.

Generalized cowpox infection in the Patagonian cavy may represent a threat to the health of immunocompromised persons. We report the first case of cowpoxvirus infection in the Patagonian cavy in an educational animal park. The mara developed extensive pox lesions, shedding large amounts of viral particles. The ending of vaccination programmes against smallpox in the late 1970's may lead to an increase in susceptibility of humans to zoonotic poxviruses.

Leafy head formation of the progenies of transgenic plants of Chinese cabbage with exogenous auxin genes.

The experiment was performed to evaluate the progenies of plant lines transgenic for auxin synthesis genes derived from Ri T-DNA. Four lines of the transgenic plants were self-crossed and the foreign auxin genes in plants of T5 generation were confirmed by Southern hybridization. Two lines, D1232 and D1653, showed earlier folding of expanding leaves than untransformed line and therefore had early initiation of leafy head. Leaf cuttings derived from plant of transgenic line D1653 produced more adventitious roots than the control whereas the cuttings from folding leaves had much more roots than rosette leaves at folding stage, and the cuttings from head leaves had more roots than rosette leaves at heading stage. It is demonstrated that early folding of transgenic leaf may be caused by the relatively higher concentration of auxin. These plant lines with auxin transgenes can be used for the study of hormonal regulation in differentiation and development of plant organs and for the breeding of new variety with rapid growth trait.

Molecular characters and morphological genetics of CAL gene in Chinese cabbage.

BcpCAL, the homologous gene of CAL, was isolated from Chinese cabbage. Unlike BobCAL of cauliflower, BcpCAL did not hold the terminating mutation in the fifth exon. After crosses of cauliflower with Chinese cabbage, the resultant hybrids failed to form curd, which implicates the genetic complement of BcpCAL to the mutated BobCAL in the function of curd formation. One of CAL gene isolated from the hybrid apparently comes from the female parent (Chinese cabbage) even though there are a few of the bases substituted and deleted. The result offers the molecular and genetic evidences for the study of biological function of CAL in morphological genetics of curd.

Glycine-activated chloride currents of neurons freshly isolated from the ventral tegmental area of rats.

Properties of whole-cell glycine currents (IGly) of ventral tegmental area (VTA) neurons from 3- to 7-day old Sprague-Dawley rats were investigated with the patch-clamp technique. Ninety-three percent of the 126 neurons examined produced IGly in response to glycine. For 70% of these neurons, IGly did not decay in response to a threshold concentration of glycine (1-5 microM). At elevated glycine concentrations, IGly consistently decayed from a peak to a steady state (SS). IGly increased in amplitude sigmoidally as a function of the concentration of agonist with an EC50 of 32 microM. Strychnine (STR), when co-applied with glycine after a prepulse of STR, suppressed both the peak and SS IGly noncompetitively. In the absence of a prepulse, STR had a smaller effect on peak IGly while increasing its decay rate; the SS amplitude decreased. These STR effects were concentration dependent with an IC50 of 31 nM and 184 nM STR for the peak and SS IGly, with prepulse, respectively, and 732 nM and 193 nM for the peak and SS IGly, respectively, without prepulse. Picrotoxin (PTX) co-applied with glycine suppressed both the peak and the SS IGly with an IC50 of 25 microM. In contrast to STR, 1 min preincubation with PTX had no effect on IGly. Thus, PTX acts on the open channel. The inhibitory effects of both STR and PTX on IGly did not depend on the membrane potential.

Cocaine depresses GABAA current of hippocampal neurons.

Although blockade of dopamine re-uptake and the resulting elevation of excitatory agonists is commonly thought the primary mechanism of cocaine-induced seizures, it is possible that other neurotransmitters such as gamma-aminobutyric acid (GABA) are involved. To examine this possibility, the effects of cocaine on the whole cell GABA current (IGABA) of freshly isolated rat hippocampal neurons were investigated with the patch-clamp technique. Preincubation or acute application of cocaine reversibly suppressed IGABA. The IC50 was 127 microM when cocaine was applied before the application of GABA. The concentration-response relations of cocaine in various GABA concentrations revealed that cocaine inhibited IGABA non-competitively. This effect of cocaine appeared to be independent of voltage. The present study suggests that the GABA receptor/channel complex is also a target for cocaine's action. The suppression of IGABA may contribute to cocaine-induced seizures.

Cocaine and lidocaine have additive inhibitory effects on the GABAA current of acutely dissociated hippocampal pyramidal neurons.

Inhibition mediated by gamma-aminobutyric acid (GABA) is a major target for the central actions of cocaine and lidocaine, which can result in seizures, especially when these drugs are abused in combination. In the present study, we investigated how cocaine and lidocaine interact to depress GABA current (IGABA), recorded by the whole-cell technique in freshly isolated rat hippocampal neurons. Cocaine depressed IGABA in a concentration dependent manner, such that cocaine was more potent against lower than higher GABA concentrations: the cocaine IC50 was 0.13, 0.62 and 1.2 mM for GABA at 2, 10 and 100 microM, respectively. Cocaine depressed IGABA to the same extent in the absence and presence of 1 microM tetrodotoxin, indicating that cocaine inhibition of IGABA is distinct from its Na+ channel blocking action. Lidocaine reversibly depressed IGABA evoked by 10 microM GABA, with an IC50 of 9.8 mM. In the presence of 3 mM lidocaine, 0.3 mM cocaine depressed IGABA (10 microM GABA) to 30+/-7%. The significantly greater depression by the combined agents (p<0.05) indicates additive effects on the GABA receptor/channel complex, which are likely to contribute to the additive convulsant effects noted when these drugs are abused in combination.