[Early experience with mechanical hemodynamic support for catheter ablation of malignant ventricular tachycardia].

Objective: To explore the role of mechanical hemodynamic support (MHS) in mapping and catheter ablation of patients with hemodynamically unstable ventricular tachycardia (VT), report single-center experience in a cohort of consecutive patients receiving VT ablation during MHS therapy, and provide evidence-based medical evidence for clinical practice. Methods: This was a retrospective cohort study. Patients with hemodynamically unstable VT who underwent catheter ablation with MHS at Beijing Anzhen Hospital, Capital Medical University between August 2021 and December 2023 were included. Patients were divided into rescue group and preventive group according to the purpose of treatment. Their demographic data, periprocedural details, and clinical outcomes were collected and analyzed. Results: A total of 15 patients with hemodynamically unstable VT were included (8 patients in the rescue group and 7 patients in the preventive group). The acute procedure was successful in all patients. One patient in the rescue group had surgical left ventricular assist device (LVAD) implantation, remaining 14 patients received extracorporeal membrane oxygenation (ECMO) for circulation support. ECMO decannulation was performed in 12 patients due to clinical and hemodynamic stability, of which 6 patients were decannulation immediately after surgery and the remaining patients were decannulation at 2.0 (2.5) d after surgery. Two patients in the rescue group died during the index admission due to refractory heart failure and cerebral hemorrhage. During a median follow-up of 30 d (1 d to 12 months), one patient with LVAD had one episode of ventricular fibrillation at 6 months after discharge, and no further episodes of ventricular fibrillation and/or VT occurred after treatment with antiarrhythmic drugs. No malignant ventricular arrhythmia occurred in the remaining 12 patients who were followed up. Conclusions: MHS contributes to the successful completion of mapping and catheter ablation in patients with hemodynamically unstable VT, providing desirable hemodynamic status for emergency and elective conditions.

[Feasibility and safety of intracardiac ultrasound-assisted atrial septal puncture during radiofrequency ablation for atrial fibrillation].

Objective: To explore the feasibility and safety of intracardiac ultrasound-assisted atrial septal puncture (ASP) during radiofrequency ablation for atrial fibrillation. Methods: We enrolled 241 consecutive patients scheduled to radiofrequency ablation for atrial fibrillation in Beijing Anzhen Hospital from July to September 2020. Inclusion criteria: patients aged over 18 years with a clear electrocardiogram record of atrial fibrillation. Patients were divided into 2 groups: ASP with ultrasound-assisted X-ray (ultrasound group, n=123), ASP under X-ray alone (X-ray group, n=118). Clinical features of patients including age, sex, percent of paroxysmal atrial fibrillation, and repeat ablation, CHA2DS2-VASc score and past history (hypertension, diabetes mellitus, coronary artery disease, stroke/transient ischemic attack (TIA), valve diseases) and echocardiographic parameters (left atrial dimension, left ventricular ejection fraction, left ventricular end-diastolic dimension) were obtained and compared. The first-pass rate, radiation exposure time, duration of ASP, and complications of ASP were also compared between the two groups. Results: The age of patients in this cohort was (62.5±8.0) years, and the proportion of males was 57.0% (n=138). Among them, the proportion of paroxysmal atrial fibrillation was 56.0% (n=135), and the ratio of repeat ablation was 17.8% (n=43). Age, sex, percent of paroxysmal atrial fibrillation, history of hypertension, diabetes mellitus were similar between the two groups. The first-pass rate was significantly higher in the ultrasound group than in the X-ray group (94.3% (116/123) vs. 79.7% (94/118), P=0.001); the exposure time of X-ray was significantly shorter in the ultrasound group than in the X-ray group ((31.3±7.9) s vs. (124.8±35.7) s, P<0.001), while the duration of ASP was longer in the ultrasound group ((10.1±1.8) minutes vs. (8.2±1.3) minutes, P<0.001). In terms of complications, the incidence of puncture into the pericardium was lower in the ultrasound group (0 vs.3.4% (4/118), P=0.039); the rate of transient ST-segment elevation post ASP was similar between the ultrasound group and X-ray group (2.4% (3/123) vs. 1.7% (2/118), P=0.999). Conclusion: Intracardiac ultrasound-assisted atrial septal puncture can effectively improve the accuracy of atrial septal puncture, shorten the radiation exposure time, and reduce the complications related to atrial septal puncture.

[Efficacy and safety of catheter ablation in patients with new-onset atrial arrhythmia after surgical excision of left atrial myxoma].

Objective: To evaluate the safety and efficacy of catheter ablation in patients with new-onset atrial arrhythmia after surgical excision of left atrial myxoma. Methods: Nine patients with new onset atrial arrhythmia and a prior history of left atrial myxoma, who received surgical myxoma excision and catheter ablation between September 2014 and November 2019, were included in the present study. Baseline characteristics, procedural parameters during catheter ablation, severe perioperative adverse events, recurrence rate of arrhythmia and clinical prognosis were analyzed. Kaplan Meier survival analysis was used to define the maintenance rate of sinus rhythm after catheter ablation in this patient cohort. Results: Nine patients were included. The average age was (55.8 ± 9.1) years old (3 male), there were 3 patients (3/9) with paroxysmal atrial fibrillation (PAF) and 6 patients (6/9) with atrial flutter or atrial tachycardia (AFL or AT). Ablation was successful in all patients, there were no perioperative complications such as stroke, pericardial effusion, cardiac tamponade, vascular complications or massive hemorrhage. During a mean follow-up time of 40.0 (27.5, 55.5) months, sinus rhythm was maintained in six patients (6/9) after the initial catheter ablation. The overall sinus rhythm maintenance rate was 2/3. In addition, 1 out of the 3 AF patients (1/3) developed recurrence of AF at 3 month after ablation, and 2 out of the 6 AFL or AT patients (2/6) developed late recurrence of AF or AFL (19 months and 29 months after ablation), two out of three patients with recurrent AFs or AFL received repeated catheter ablation and one patient remained sinus rhythm post repeat ablation. Meanwhile, there was no recurrence of atrial myxoma, no death, stroke, acute myocardial infarction and other events during the entire follow-up period. Conclusions: Catheter ablation is a safe and feasible therapeutic option for patients with new-onset atrial arrhythmia after surgical excision of left atrial myxoma.

[Electrophysiological characteristics and therapeutic efficacy of radiofrequency ablation of focal atrial tachycardia originating from the right atrial appendage during pregnancy].

Objective: To analyze the electrophysiological characteristics and the therapeutic efficacy of irrigated-tip catheter radiofrequency ablation(RFA) without radiation for pregnant women with focal atrial tachycardia(AT) originating from the right atrial appendage (RAA). Methods: Data from 55 women with focal AT, who underwent radiofrequency ablation (RFA) in the First Affiliated Hospital of Zhengzhou University from October 2016 to March 2019, were screened. 2 non-pregnant women with right atrial appendage tachycardia (RAAT) and 4 pregnant women with non-RAAT were excluded. The remaining 49 cases were divided into RAAT during pregnancy group (n=6, including 4 cases of tachycardia-induced cardiomyopathy) and non-pregnant and non-RAAT group (control, n=43). Under the guidance of three-dimensional mapping system, the earliest activation site was identified, RFA with the irrigated catheter without x-ray fluoroscopy was performed in RAAT patients during pregnancy, all patients in control group underwent non-zero-ray ablation. Patients were followed up at 3, 6, 12 months post procedure, and yearly follow up thereafter in outpatient clinic. Electrocardiogram or Holter monitoring was performed during follow up. AT recurrence and surgical complications were recorded during follow up. At 6 months after RFA, echocardiography examination and laboratory examination including N-terminal B-type brain natriuretic peptide measurement were performed in the pregnant patients, delivery results were also recorded in the pregnant patients. The electrophysiological characteristics of RAAT during pregnancy were analyzed, the therapeutic efficacy of RFA was compared between the two groups. Results: This study is a retrospective study. Age ((30.7±6.2)years vs. (57.2±11.7)years), left ventricular ejection fraction ((46.0±12.8)% vs. (60.1±5.9)%), proportions of organic heart disease (0% vs. 58%) were significantly lower in the RAAT patients during pregnancy group than in control group (P<0.05), while proportions of patients with persistent tachycardia (100% vs. 7%), symptoms of chest distress and palpitation (6/6 vs. 49%) and left ventricular ejection farction≤50% (4/6 vs. 9%) were significantly higher in RAAT group than in control group (P<0.05), heart rate was similar between the two groups ((163.7±11.1)beats/minutes vs. (153.7±15.2)beats/minutes, P>0.05). The characteristic P-wave morphology was observed in RAAT patients during pregnancy, i.e, P wave was mostly upright (5/6) in inferior-leads (Ⅱ, Ⅲ, aVF) and in lead I and aVL, deep and wide negative P wave was found in V1 lead (5/6), and gradually became positive from V2-V6. The mean tachycardia cycle length was (361.7±38.5) ms. Three-dimensional mapping showed that the origin points of the 6 RAAT pregnant patients were all scattered in the local region, the local region was ablated accordingly, 2 patients (2/6) received extensive ablation of local areas. Immediate successful rate was similar between the two groups (6/6 vs. 93%). During follow up ((15.3±4.0) months), no complications were observed after RFA, postoperative recurrence rate was similar (1/6 vs. 12%). Uncomplicated delivery was reported in all 6 pregnant RAAT post ablation. Normal cardiac structure and function was observed in the 4 pregnant patients with tachycardia-induced cardiomyopathy post ablation. Compared to pre-ablation phase, reduced left atrial dimension ((30.3±1.3) mm vs. (36.8±6.7) mm, P>0.05), increased left ventricular ejection fraction ((64.0±2.9)% vs. (39.8±10.7)%), reduced left ventricular end-diastolic dimension ((44.8±4.0) mm vs. (60.0±2.9) mm) and reduced N-terminal B-type natriuretic peptide value ((136.2±47.5) ng/L vs. (3 408.4±901.3) ng/L) were observed at 6 months post ablation (P<0.05). Conclusion: The electrophysiological characteristics are suggestive for focal AT originating from RAA during pregnancy. Under the guidance of 3-dimension activation mapping, no fluoroscopic RFA with irrigated-tip catheter is a safe and effective strategy for the treatment of focal RAAT during pregnancy.

Effects of selenium and light wavelengths on liquid culture of Cordyceps militaris Link.

To investigate the effects of selenium and light wavelengths on the growth of liquid-cultured Cordyceps militaris and the main active components' accumulation, culture conditions as selenium selenite concentrations and light of different wavelengths were studied. The results are: adenosine accumulation proved to be significantly selenium dependent (R(2) = 0.9403) and cordycepin contents were determined to be not significantly selenium dependent (R(2) = 0.3845) but significantly enhanced by selenium except for 20 ppm; there were significant differences in cordycepin contents, adenosine contents, and mycelium growth caused by light wavelengths: cordycepin, blue light > pink light > daylight, darkness, red light; adenosine, red light > pink light, darkness, daylight, blue light; and mycelium growth, red light > pink light, darkness, daylight > blue light. In conclusion, light wavelength had a significant influence on production of mycelia, adenosine, and cordycepin, so lightening wavelength should be changed according to target products in the liquid culture of C. militaris.

Discovery and characterization of taspoglutide, a novel analogue of human glucagon-like peptide-1, engineered for sustained therapeutic activity in type 2 diabetes.

AIM: Glucagon-like peptide-1 (GLP-1) receptor agonists for the treatment of type 2 diabetes are administered by daily injection because of short plasma half-lives, which result partly from the biochemical instability of these peptides. There is a medical need for GLP-1 analogues that can be administered less frequently for patient convenience. METHODS: We synthesized a series of human GLP-1 (hGLP-1(7-36)NH(2) ) derivatives containing α-aminoisobutyric acid (Aib) substitutions, analysed their enzymatic stabilities and evaluated their secondary structures using circular dichroism (CD) and nuclear magnetic resonance (NMR). RESULTS: Plasma stability experiments showed that only the analogue containing Aib substitutions in both the N-terminus (position 8) and the C-terminus (position 35), [Aib8(,)³5]hGLP-1(7-36)NH2 (BIM-51077), was fully resistant to enzymatic cleavage. Incubation with human plasma kallikrein or plasmin confirmed that the Aib substitution at position 35 prevented protease cleavage around this residue, which contributes to the significantly enhanced plasma stability and increased plasma half-life. CD revealed increased C-terminal α-helicity in Aib³5-substituted analogues compared with both hGLP-1(7-36)NH2 and analogues containing only Aib8 substitutions. Based on NMR studies, the secondary structure of BIM-51077 is similar to hGLP-1(7-36)NH2 with a slight increase in α-helicity in the C-terminus. Compared with hGLP-1(7-36)NH2, BIM-51077 had similar binding affinity for the human GLP-1 receptor and activated this receptor with similar potency. CONCLUSIONS: We have discovered an Aib8(,)³5-substituted analogue of native hGLP-1(7-36)NH2 (BIM-51077) that retains the structure of the native peptide, and has similar activity and enhanced stability. A sustained-release formulation of this molecule (taspoglutide) is in phase-3 clinical development.

The effect of selective sst1, sst2, sst5 somatostatin receptors agonists, a somatostatin/dopamine (SST/DA) chimera and bromocriptine on the "clinically non-functioning" pituitary adenomas in vitro.

The aim of the work was to investigate the effects of somatostatin analogs acting selectively on sst1 (BIM-23926), sst2 (BIM-23120) and sst5 (BIM-23206) receptor subtypes on the viability of "clinically non-functioning" pituitary adenomas in vitro. The effects of native SST (SST-14), a SST/DA chimera (BIM-23A387) and a D(2)-dopamine receptor agonist bromocriptine (BC) were also examined. The study was performed on 10 surgically removed pituitary macroadenomas, diagnosed before surgery as "non-functioning". A part of each tumor was mechanically dispersed and digested with collagenase to isolate the tumoral cells. Another part of each tumor was fixed, embedded in paraffin and immunostained to reveal the pituitary hormones and SST receptor subtypes (sst1, sst2A, sst2B, sst3, sst4, sst5). The tumoral cell suspensions were incubated for 24 h with the substances mentioned above. The quantity of viable cells was estimated using the EZ4U system. The results were compared with the immunohistochemical evaluation of the hormonal profile of adenoma and the sst receptor subtype immunoreactivities present. The findings indicate that selective sst1, sst2 and sst5 receptors agonists, SST/DA chimera and D(2)-dopamine receptor agonist bromocriptine affect the viability of some, but not all, "clinically non-functioning" pituitary adenomas in vitro. The most effective was bromocriptine. The investigated somatostatin analogs including SST/DA chimera exerted roughly similar inhibitory effects. Further studies are needed to fully evaluate the potential usefulness of these compounds in the pharmacological treatment of "non-functioning" pituitary tumors.

Endogenous ghrelin regulates episodic growth hormone (GH) secretion by amplifying GH Pulse amplitude: evidence from antagonism of the GH secretagogue-R1a receptor.

Ghrelin was purified from rat stomach as an endogenous ligand for the GH secretagogue (GHS) receptor. As a GHS, ghrelin stimulates GH release, but it also has additional activities, including stimulation of appetite and weight gain. Plasma GH and ghrelin secretory patterns appear unrelated, whereas many studies have correlated ghrelin variations with food intake episodes. To evaluate the role of endogenous ghrelin, GH secretion and food intake were monitored in male rats infused sc (6 mug/h during 10 h) or intracerebroventricularly (5 microg/h during 48 h) with BIM-28163, a full competitive antagonist of the GHS-R1a receptor. Subcutaneous BIM-28163 infusion significantly decreased GH area under the curve during a 6-h sampling period by 54% and peak amplitude by 46%. Twelve hours after the end of treatment these parameters returned to normal. Central treatment was similarly effective (-37 and -42% for area under the curve and -44 and -49% for peak amplitude on the first and second days of infusion, respectively). Neither peripheral nor central BIM-28163 injection modified GH peak number, GH nadir, or IGF-I levels. In this protocol, food intake is not strongly modified and water intake is unchanged. Subcutaneous infusion of BIM-28163 did not change plasma leptin and insulin levels evaluated at 1200 and 1600 h. On the contrary, central BIM-28163 infusion slightly increased leptin and significantly increased insulin concentrations. Thus, endogenous ghrelin, through GHS-R1a, acts as a strong endogenous amplifier of spontaneous GH peak amplitude. The mechanisms by which ghrelin modifies food intake remain to be defined and may involve a novel GHS receptor.

Use of the excluded protecting group (EPG) method for peptide synthesis.

The excluded protecting group (EPG) method has been used for the solution synthesis of several peptides including Merrifield's Model Tetrapeptide, linear antamanide and an analogue of magainin-1, [Ala(19), Asn(22)]magainin-1. In the approach reported, the C-terminal amino acid is esterified to the 2-position of cholestane as the [2s,3s]iodohydrin ester and the penultimate amino acid added to the aminoacyl-steroid as the Fmoc-pentafluorophenyl-ester. The Fmoc group is removed with Et(2)NH/DMF ( approximately 15% v/v) and, after evaporation to approximately 10 mL, the solution chromatographed on Sephadex LH-20 in DMF. The dipeptidyl-steroid elutes as the free amine well separated from other reaction mixture components. Fractions containing the dipeptide, as determined by counting and TLC, are pooled and reacted with the next Fmoc-amino acid-pentafluorophenyl ester in the sequence. Repetition of the deprotection/purification/reaction cycle yields the fully protected peptide. On completion of the synthesis, the cholestane iodohydrin ester is selectively removed by treatment with Zn degrees /AcOH to yield the peptide with intact alpha-amino and side chain protecting groups. Global deprotection is achieved with HF. All intermediates from the syntheses reported were characterized. The magainin analogue was shown to have full biologic activity. The Fmoc iodohydrin esters of 16 of the 20 proteogenic amino acids have been prepared and characterized for use as the C-terminal amino acids in other EPG syntheses.

Novel ghrelin analogs with improved affinity for the GH secretagogue receptor stimulate GH and prolactin release from human pituitary cells.

OBJECTIVE: Ghrelin, a recently identified 28-amino acid peptide is a potent GH secretagogue (GHS) produced predominantly by the stomach. Ghrelin stimulates GH secretion through binding to the GHS receptor in the hypothalamus and pituitary. In addition to the GH-releasing action, ghrelin has been found to be a powerful orexigenic factor. To assess the direct in vitro effects of ghrelin on human pituitary hormone secretion we have produced a panel of novel ghrelin analogs (molecular weight, 3323-3384; human native ghrelin, 3371) with enhanced affinity for the human GHS receptor (IC(50) 0.38-1.09 nM; human ghrelin, 1.2-2.2 nM). METHODS: The peptidic analogs were tested for their effect on GH secretion using dispersed human fetal pituitaries (21 to 23 weeks of gestation) and cultured GH- and prolactin (PRL)-secreting adenomas. The expression of the GHS receptor in normal (fetal and adult) human pituitary tissues, GH- and PRL-cell adenomas was established using RT-PCR. RESULTS: The effects of ghrelin, its analogs and GH-releasing hormone (GHRH) alone or in combination on GH and PRL secretion were compared at various concentrations. The ghrelin analogs stimulated GH release by 35-60% from human fetal pituitary cells (1-10 nM; P<0.05) and by 50-75% from cultured pituitary adenomas (10 nM; P<0.05). This releasing effect was dose-dependent, achieving maximal stimulation with analog concentrations at 100 nM. Human ghrelin was less potent as compared with its analogs in stimulating human GH, in keeping with the improved binding affinity of the analogs for the GHS-1a receptor. The ghrelin analogs and GHRH had comparable effects on GH secretion from both normal and adenomatous cells, and in combination produced an additive stimulatory effect on GH (150%; P<0.0001). In contrast, ghrelin and its analogs induced a comparable increase in PRL release ranging between 25 and 40% (P<0.05) from fetal cells and 30 and 70% (P<0.001) from cultured PRL-cell and mixed GH-PRL adenomas. CONCLUSIONS: Our results have demonstrated for the first time that ghrelin analogs with enhanced affinity for the GHS receptor are potent stimulators of GH secretion from human pituitary cells, and thus may possess potential clinical therapeutic benefits.

Somatostatin receptor subtype specificity in human fetal pituitary cultures. Differential role of SSTR2 and SSTR5 for growth hormone, thyroid-stimulating hormone, and prolactin regulation.

Somatostatin (SRIF), a hypothalamic inhibitor of pituitary growth hormone (GH) and thyroid-stimulating hormone (TSH) secretion, binds to five distinct receptor (SSTR) subtypes. We therefore tested SSTR subtype-specific SRIF analogs in primary human fetal pituitary cultures (23-25-wk gestation) to elucidate their role in regulating human pituitary function. Using reverse transcription-PCR, mRNA expression of SSTR2 and SSTR5 were detected in fetal pituitary by 25 wk. SRIF analog affinities were determined by membrane radioligand binding in cells stably expressing the human SSTR forms. GH secretion was suppressed equally (40-60%, P < 0.005) by analogs preferential for either SSTR2 (IC50 for receptor binding affinity, 0.19-0.42 nM) or SSTR5 (IC50, 0.37 nM), and compounds with enhanced affinity for SSTR2 were more potent (EC50 for GH suppression, 0.05-0.09 nM) than Lanreotide (EC50, 2.30 nM) and SRIF (EC50, 0.19 nM). Similarly, analogs with high affinity for SSTR2 or SSTR5 decreased TSH secretion (30-40%, P < 0.005). However, prolactin was effectively inhibited only by compounds preferentially bound to SSTR2 (20-30%, P < 0.05). Luteinizing hormone was modestly decreased (15-20%) by SSTR2- or SSTR5-specific analogs. An SSTR5-specific analog also exclusively inhibited GH in acromegalic tumor cells. Thus, SRIF regulation of GH and TSH in primary human fetal pituitary cells is mediated by both SSTR2 and SSTR5, both of which are abundantly expressed by 25 wk. In contrast, suppression of prolactin is mediated mainly by SSTR2. These results indicate that SSTR5 is critical for physiologic regulation of GH and TSH. SRIF analogs with selective affinity for this receptor may therefore be more effective in the treatment of hormone-secreting pituitary adenomas.

Influences of altered phytohormone use on endogenous ABA and mRNA populations during white spruce (Picea glauca) somatic embryo culture.

We examined endogenous abscisic acid [(+)-ABA] amounts and mRNA populations in white spruce (Picea glauca (Moench) Voss) somatic embryos in liquid suspension culture during a pretreatment prior to induction of maturation with exogenous (+)-ABA. The pretreatment consisted of removal of 2,4-dichlorophenoxyacetic acid (2,4-D) from the multiplication medium for 7 days. The removal of 2,4-D resulted in a slight increase in endogenous ABA in pretreated tissues compared to nonpretreated tissues at the end of the 7-day pretreatment period (42.4 versus 20.0 pg mg(-1) lyophilized tissue). Altered gene expression patterns were observed as early as one day after the start of the pretreatment, with more than 17 new polypeptides found in pretreated tissues. The influence of pretreatment continued to be observed after tissues were transferred to ABA-containing maturation medium. By comparing mRNA populations in pretreated and nonpretreated tissues cultured on either ABA-containing or ABA-free maturation medium, at least 12 mRNAs were observed to be induced by ABA, among which three polypeptides were ABA inducible only in pretreated tissues.

A reliable method for extraction of RNA from various conifer tissues.

A simple and efficient procedure suitable for extraction of high-quality RNA from cultured conifer tissues, somatic embryos, zygotic embryos, needles, stem and root tissues was developed. It produced from 100 µg up to 700 µg total RNA per gram tissue dependent on the types of tissues used. RNA quality was estimated by spectrophotometry, agarose gel electrophoresis, in vitro translation of mRNA, cDNA synthesis and Northern blot analysis. The method also worked well with Arabidopsis thaliana and tobacco tissues.

Prevalence of genital Chlamydia trachomatis infection in selected populations in China.

BACKGROUND: Chlamydia trachomatis is an important pathogen of the urogenital tract. Numerous epidemiologic studies have reported on the prevalence of chlamydia world wide. However, the prevalence of Chlamydia trachomatis in China has not been widely studied. GOAL OF THIS STUDY: To identify Chlamydia trachomatis in three distinct populations in China. Urogenital specimens were collected from men with no prior history of sexual intercourse (virgin), men seen at a sexually transmitted disease clinic, and female prostitutes. STUDY DESIGN: Two-hundred urethral swabs were collected from group one, and 100 urethral swabs from group two, and 109 cervical swabs from group three. All specimens were tested for chlamydia by tissue culture isolation using McCoy cells and an iodine stain. RESULTS: Chlamydia trachomatis was not isolated from the virgin males. The prevalence of chlamydia in men seen at a sexually transmitted disease clinic was 13% (13/100) and in female prostitutes, 37.6% (41/109). CONCLUSION: The prevalence of chlamydia seen in these three groups is similar to rates found in previous studies done in the United States and Europe in similar populations. Patients with multiple sex partners in China need to be screened for C. trachomatis.