Medium-Chain Lipid Conjugation Facilitates Cell-Permeability and Bioactivity.

The majority of bioactive molecules act on membrane proteins or intracellular targets and therefore needs to partition into or cross biological membranes. Natural products often exhibit lipid modifications to facilitate critical molecule-membrane interactions, and in many cases their bioactivity is markedly reduced upon removal of a lipid group. However, despite its importance in nature, lipid-conjugation of small molecules is not commonly used in chemical biology and medicinal chemistry, and the effect of such conjugation has not been systematically studied. To understand the composition of lipids found in natural products, we carried out a chemoinformatic characterization of the "natural product lipidome". According to this analysis, lipidated natural products predominantly contain saturated medium-chain lipids (MCLs), which are significantly shorter than the long-chain lipids (LCLs) found in membranes and lipidated proteins. To study the usefulness of such modifications in probe design, we systematically explored the effect of lipid conjugation on five different small molecule chemotypes and find that permeability, cellular retention, subcellular localization, and bioactivity can be significantly modulated depending on the type of lipid tail used. We demonstrate that MCL conjugation can render molecules cell-permeable and modulate their bioactivity. With all explored chemotypes, MCL-conjugates consistently exhibited superior uptake or bioactivity compared to LCL-conjugates and either comparable or superior uptake or bioactivity to short-chain lipid (SCL)-conjugates. Together, our findings suggest that conjugation of small molecules with MCLs could be a powerful strategy for the design of probes and drugs.

Focal High Intensity Focused Ultrasound of Unilateral Localized Prostate Cancer: A Prospective Multicentric Hemiablation Study of 111 Patients.

BACKGROUND: Up to a third of patients with localized prostate cancer have unilateral disease that may be suitable for partial treatment with hemiablation. OBJECTIVE: To evaluate the ability of high intensity focused ultrasound (HIFU) to achieve local control of the tumor in patients with unilateral localized prostate cancer. DESIGN, SETTING, AND PARTICIPANTS: The French Urological Association initiated a prospective IDEAL multi-institutional study (2009-2015), to evaluate HIFU-hemiablation as a primary treatment. INTERVENTION: Multiparametric magnetic resonance imaging and biopsy were used for unilateral cancer diagnosis and control, and HIFU-hemiablation. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Primary: absence of clinically significant cancer (CSC) on control biopsy at 1 yr (CSC: Gleason score ≥ 7 or cancer core length>3mm regardless of grade or > 2 positive cores). Secondary: presence of any cancer on biopsy, biochemical response, radical treatment free survival, adverse events, continence (no pad), erectile function (International Index of Erectile Function-5 ≥ 16), and quality of life (European Organization for Research and Treatment of Cancer QLQ-C28) questionnaires. RESULTS AND LIMITATIONS: One hundred and eleven patients were treated (mean age: 64.8 yr [standard deviation 6.2]; mean prostate-specific antigen: 6.2 ng/ml [standard deviation 2.6]; 68% low risk, 32% intermediate risk). Of the 101 patients with control biopsy, 96 (95%) and 94 (93%) had no CSC in the treated and contralateral lobes, respectively. Mean prostate-specific antigen at 2 yr was 2.3 ng/ml (standard deviation 1.7). The radical treatment-free survival rate at 2 years was 89% (radical treatments: six radical prostatectomies, three radiotherapies, and two HIFU). Adverse events were Grade 3 in 13%. At 12 mo continence and erectile functions were preserved in 97% and 78%. No significant decrease in quality of life score was observed at 12 mo. One limitation is the number of low-risk patients included in this study. CONCLUSIONS: At 1 yr, HIFU-hemiablation was efficient with 95% absence of clinically significant cancer associated with low morbidity and preservation of quality of life. Radical treatment-free survival rate was 89% at 2 yr. PATIENT SUMMARY: This report shows that high intensity focused ultrasound half-gland treatment of unilateral prostate cancer provides promising results with high cancer control and low morbidity.

Renal cell carcinoma (RCC) in patients with end-stage renal disease exhibits many favourable clinical, pathologic, and outcome features compared with RCC in the general population.

BACKGROUND: Patients with end-stage renal disease (ESRD) are at risk of developing renal tumours. OBJECTIVE: Compare clinical, pathologic, and outcome features of renal cell carcinomas (RCCs) in ESRD patients and in patients from the general population. DESIGN, SETTING, AND PARTICIPANTS: Twenty-four French university departments of urology participated in this retrospective study. INTERVENTION: All patients were treated according to current European Association of Urology guidelines. MEASUREMENTS: Age, sex, symptoms, tumour staging and grading, histologic subtype, and outcome were recorded in a unique database. Categoric and continuous variables were compared by using chi-square and student statistical analyses. Cancer-specific survival (CSS) was assessed by Kaplan-Meier and Cox methods. RESULTS AND LIMITATIONS: The study included 1250 RCC patients: 303 with ESRD and 947 from the general population. In the ESRD patients, age at diagnosis was younger (55 ± 12 yr vs 62 ± 12 yr); mean tumour size was smaller (3.7 ± 2.6 cm vs 7.3 ± 3.8 cm); asymptomatic (87% vs 44%), low-grade (68% vs 42%), and papillary tumours were more frequent (37% vs 7%); and poor performance status (PS; 24% vs 37%) and advanced T categories (≥ 3) were more rare (10% vs 42%). Consistently, nodal invasion (3% vs 12%) and distant metastases (2% vs 15%) occurred less frequently in ESRD patients. After a median follow-up of 33 mo (range: 1-299 mo), 13 ESRD patients (4.3%), and 261 general population patients (27.6%) had died from cancer. In univariate analysis, histologic subtype, symptoms at diagnosis, poor PS, advanced TNM stage, high Fuhrman grade, large tumour size, and non-ESRD diagnosis context were adverse predictors for survival. However, only PS, TNM stage, and Fuhrman grade remained independent CSS predictors in multivariate analysis. The limitation of this study is related to the retrospective design. CONCLUSIONS: RCC arising in native kidneys of ESRD patients seems to exhibit many favourable clinical, pathologic, and outcome features compared with those diagnosed in patients from the general population.

Randomized, crossover study evaluating patient preference and the impact on quality of life of urisheaths vs absorbent products in incontinent men.

OBJECTIVE: • To evaluate the impact of urisheaths vs absorbent products (APs) on quality of life (QoL) in men with moderate to severe urinary incontinence (UI). PATIENTS AND METHODS: • A randomized, controlled, crossover trial in 61 outpatient adult men with stable, moderate to severe UI, with no concomitant faecal incontinence, was conducted from June 2007 to February 2009 in 14 urology centres. • Participants tested Conveen Optima urisheaths (Coloplast, Humlebaek, Denmark) with collecting bags and their usual AP in random order for 2 weeks each. • The impact of each on QoL was measured using the King's Health Questionnaire (KHQ) and the short form-12 acute questionnaire, and each patient's preference was recorded. • A 10-item patient questionnaire was also used to assess the product main advantages on an 11-point scale (0: worst; 10: best). A 72-h leakage diary was used to record the number and severity of leaks and daily product consumption. Safety was measured as the number of local adverse events. RESULTS: • All dimensions of the KHQ were scored lower with urisheaths, indicating an improvement in QoL. The greatest mean score reductions were in Limitations of Daily Activities (-10.24, P= 0.01) and Incontinence Impact (-7.05, P= 0.045). • The majority (69%) of patients preferred Conveen Optima urisheaths to their usual AP (P = 0.002). • Urisheaths scored significantly higher for all categories in the patient questionnaire (efficacy, self-image, odour management, discretion, skin integrity) except ease of use. • Safety was considered to be good. CONCLUSIONS: • Conveen Optima urisheaths showed a positive impact on QoL (according to the KHQ results) in moderate to severe incontinent men, who were long-term users of APs, and participants largely preferred urisheaths. • Conveen Optima urisheaths should be recommended to incontinent men in preference to APs.

Which efficiency index for urinary stones treatment?

Clinical results in urinary stones management are often reported using the stone-free (SF) rate, which is simple, reproducible and useful to compare techniques or centers. But this index does not take into account costs or patients' quality of life. In a way, SF "pursuit", which cannot be considered as a universal therapeutic goal could increase costs and decrease patients' comfort. We retrospectively reviewed files of stone management to describe costs according to several items and we emphasize the need for a true efficiency index.

Synaptic regulation of the light-dependent oscillatory currents in starburst amacrine cells of the mouse retina.

Responses of on-center starburst amacrine cells to steady light stimuli were recorded in the dark-adapted mouse retina. The response to spots of dim white light appear to show two components, an initial peak that correspond to the onset of the light stimulus and a series of oscillations that ride on top of the initial peak relaxation. The frequency of oscillations during light stimulation was three time higher than the frequency of spontaneous oscillations recorded in the dark. The light-evoked responses in starburst cells were exclusively dependent on the release of glutamate likely from presynaptic bipolar axon terminals and the binding of glutamate to AMPA/kainate receptors because they were blocked by 6-cyano-7-nitroquinoxalene-2,3-dione. The synaptic pathway responsible for the light responses was blocked by AP4, an agonist of metabotropic glutamate receptors that hyperpolarize on-center bipolar cells on activation. Light responses were inhibited by the calcium channel blockers cadmium ions and nifedipine, suggesting that the release of glutamate was calcium dependent. The oscillatory component of the response was specifically inhibited by blocking the glutamate transporter with d-threo-beta-benzyloxyaspartic acid, suggesting that glutamate reuptake is necessary for the oscillatory release. GABAergic antagonists bicuculline, SR 95531, and picrotoxin increased the amplitude of the initial peak while they inhibit the frequency of oscillations. TTX had a similar effect. Strychnine, the blocker of glycine receptors did not affect the initial peak but strongly decreased the oscillations frequency. These inhibitory inputs onto the bipolar axon terminals shape and synchronize the oscillatory component.

Morbidity of retropubic radical prostatectomy for prostate cancer in renal transplant recipients: multicenter study from Renal Transplantation Committee of French Urological Association.

OBJECTIVES: To evaluate the morbidity and surgical complications of retropubic radical prostatectomy (RRP) in renal transplant recipients (RTRs) and compare these results with the observed morbidity in a control group of nontransplanted patients. METHODS: We conducted a multicenter retrospective study and reviewed the charts and records of 20 RTRs who had undergone RRP for localized prostate cancer at four French renal transplant centers belonging to the Renal Transplantation Committee of the French Urological Association from April 1996 to April 2007. A total of 40 patients who had undergone RRP at the same centers, by the same surgeons, were analyzed as the case-control population. RESULTS: The mean operating time (163 +/- 41 vs 160 +/- 66 minutes), blood loss (516 +/- 279 vs 566 +/- 449 mL), transfusion rate (20% vs 22.5%), and hospital stay (11.9 +/- 5.44 vs 9.45 +/- 2.8 days) were similar in the RTR and case-control populations. No graft loss or graft injury was reported in the RTRs, except for two ureteral injuries that were immediately repaired during RRP. No decrease in the kidney graft function was observed after RRP. The rate of medical complication (deep venous thrombosis, pulmonary embolism, urinary tract infection) was similar in both groups, except for the rate of bacterial systemic infection, which was significantly greater in the RTRs than in the controls (15% vs 2.5%, P = .01). CONCLUSIONS: In our study, RRP was a safe procedure to treat localized prostate cancer in RTRs. RRP resulted in the same morbidity in RTRs as in the case-control population.

Prostate cancer in renal transplant recipients.

BACKGROUND: We conducted a retrospective multi-centre study to determine the characteristics of prostate cancer in renal transplant recipients (RTR) and to analyse the relation with immunosuppressive maintenance therapies. METHODS: Patients from 19 French transplant centres diagnosed with prostate cancer at least 1 year after kidney transplantation were included in this study. Data regarding demographics, kidney transplantation, prostate cancer and immunosuppressive treatment were analysed. RESULTS: Sixty-two patients met the eligibility criteria for this study. Thirty-eight patients (61.3%) received calcineurin inhibitors (CNI) and azathioprine (AZA) with or without steroids, twenty received CNI with or without steroids (32.2%) and four received CNI and mycophenolate mofetil (6.5%). Patients with CNI and AZA immunosuppressive therapy presented more high-stage cancer (T3 and T4) when compared to patients receiving CNI alone (47.5% versus 15%, respectively, P = 0.03). A non-significant increase in lymph node invasion was found in patients receiving CNI and AZA compared to patients receiving CNI alone (21% versus 5%, P = 0.16). In the multivariate analysis, the immunosuppressive regimen with CNI and AZA was the only independent risk factor for locally advanced disease (P = 0.007). CONCLUSION: Our results showed that RTR are at risk for early occurrence and for locally advanced prostate cancer, especially when they received a CNI and AZA maintenance immunosuppressive therapy.

[Renal complications of sickle-cell anaemia]. / Les complications rénales de la drépanocytose.

There are six described complications of sickle cell trait or disease : gross hematuria, renal infarction, papillary necrosis, nephrotic syndrome and urine concentration defects. Because of a high frequency of sickle cell trait patients among patients suffering from medullary kidney carcinoma, it has been called the seventh complication. We briefly review physiopatholgy and diagnosis of these complications.

[Evaluation of serum PSA in brain-dead subjects over the age of 50 before organ harvesting: organ donation and the risk of transmission of prostate cancer. Survey of the transplantation committee of the Association Francaise d'Urologie]. / Evaluation du taux de PSA sérique des sujets en état de mort encéphalique de plus de 50 ans avant prélèvement d'organes: risque de transmission du cancer de prostate et don d'organes. Enquête des Comités de Transplantation et de Cancérologie de l'Association Française d'Urologie.

UNLABELLED: Cancer in a brain-dead subject constitutes a contraindication to organ harvesting. However no data are available on prostatic assessment of brain-dead subjects prior to organ harvesting. The objective of this study was to evaluate prostate cancer screening by serum PSA assay in potential organ donors over the age of 50. METHODS: From February to May 2006, serum PSA assays were performed in all male donors in 5 different organ harvesting centres. The donor's age and the duration of bladder catheterization were also recorded. RESULTS: Of the 85 organ harvests performed, 30 (35.3%) concerned men over the age of 50 years (mean: 60.4 years, range: 50-82 years). The mean duration of catheterization was 3.1 days (range: 0.5-22 days). The mean PSA level was 8.7 ng/ml (range: 0.03-52.7) with a free PSA/total PSA ratio of 31% (range: 14-47). Twelve donors had a PSA level greater than 4 ng/ml (4.7 to 52 ng/ml), two others had a PSA level greater than 2.5 ng/ml (2.77 and 3.3 in subjects aged 72 and 57 years, respectively). There was no correlation between the donor's age, their PSA level and the duration of catheterization. CONCLUSION: The age of brain-dead donors is increasing and is reaching the age limit recommended by the Association Francaise d'Urologie for prostate cancer screening by digital rectal examination and PSA assay. Although the risk of transmission of prostate cancer after transplantation is currently unknown, at this stage when the majority of prostate cancers are discovered in a context of elevated PSA with normal digital rectal examination, the risk of transmission of a prostate cancer from the donor to the recipient is minimal or even non-existent. Digital rectal examination findings may be more relevant than PSA to contraindicate organ harvesting.

[Proportion of surgical workload related to chronic renal failure in an urology and transplantation operating room]. / Importance de l'activité chirurgicale liée à l'insuffisance renale chronique dans un bloc opératoire d'urologie et de transplantation.

OBJECTIVE: To evaluate the proportion of surgical workload, in terms of time and number of procedures, devoted to chronic renal failure surgery in an urology and transplantation operating room. MATERIAL AND METHODS: Analysis of the operative activity of the urology and transplantation operating room of Amiens Hospital over a period of one year (2003), by evaluating the number of procedures and the operating room occupation time (time between entry and exit from the operating room) recorded on ecology forms completed for each operation. Procedures performed in this operating room comprise conventional adult urological surgery and chronic renal failure procedures (from creation of venous access sites for haemodialysis to treatment of complications of renal transplantation). RESULTS: Surgical management of chronic renal failure in the operating room represents 22.6% of all procedures and 30.1% of the operating room occupation time. 69% of the renal transplantation operating time and 95% of kidney harvesting operating time are performed on an oncall basis. CONCLUSION: Operative activity related to chronic renal failure represents almost one third of the total surgical workload of a department managing this disease. These data justify the allocation of additional surgical resources adapted to this activity that is growing in parallel to the number of patients with chronic renal failure.

[National prospective survey on the surgical quality of renal transplants in France. Study conducted by the Association Française d'Urologie Transplantation Committee]. / Enquête nationale prospective sur la qualité chirurgicale des greffons rénaux en France. Etude du Comité de Transplantation de l'Association française d'Urologie.

STUDY OBJECTIVE: The objective of this prospective study was to describe the nature of the lesions observed during brain-dead cadavre donor kidney harvesting in France and to identify the risk factors for these lesions. MATERIAL AND METHODS: A questionnaire elaborated by the AFU Transplantation Committee concerning the quality of kidneys harvested from cadavre donors was sent to all centres performing renal transplantation in France in 2000. This prospective study was conducted over a period of 1 year and concerned the overall multi-organ harvesting procedure based on all data concerning the renal parenchyma, arteriovenous and ureteric characteristics, and the outcome of the transplants. RESULTS: Twelve centres completed the survey, allowing analysis of the data of 201 donor kidneys. 91% of harvesting surgeons were urologists. Various incidents were reported during 11% of harvesting procedures, but 1/3 of the abnormalities were not recorded by the harvesting surgeon. Isolated kidney harvesting was found to be a risk factor (20% vs 8.6%). The rate of parenchymal abnormalities was 50%, 2/3 of which were related to inadequate removal of perirenal fat. Atheroma was a risk factor for arterial lesions during harvesting (21% vs 6.50). Venous abnormalities were detected in 9% of cases: 89% of them were due to the harvesting procedure and 59% of them were not identified by the harvesting surgeon. The fact of not being a transplant surgeon was a risk factor for venous lesions (21.9% vs 6.5%). 4% of ureteric lesions were observed with no consequence on graft outcome. CONCLUSION: Adequate removal of perirenal fat before conditioning is not acquired. Isolated kidney harvesting and atheroma were risk factors for parenchymal and arterial lesions, respectively. Venous harvesting anomalies were more frequent among non-transplant surgeons.

[Haemospermia due to seminal vesicle amyloidosis. Treatment by laparoscopic vesiculectomy. A case report]. / L'hémospermie par amylose des vésicules séminales. Traitement par vésiculectomie coelioscopique. A propos d'un cas.

Amyloidosis of the seminal vesicles is a rare cause of haemospermia. The authors report the case of a 42-year-old patient with recurrent haemospermia over a period of 2 years and abnormalities of one seminal vesicle on ultrasonography and MRI, justifying laparoscopic resection. Histological examination demonstrated localized amyloidosis, secondary to inflammation. No recurrence was observed with a follow-up of one.

[Study of urothelial bladder tumours in renal transplant recipients]. / Etude des tumeurs urothéliales de vessie chez les transplantés rénaux.

OBJECTIVE: To study the prevalence, treatment and outcome of urothelial bladder tumours (UBT) in renal transplant recipients. PATIENTS AND METHODS: Multicentre retrospective study performed in 2004 by questionnaire sent to members of the AFU Transplantation Committee. RESULT: Seven centres returned the questionnaire with a total of 32 UBTs in 21 males and 3 females with a mean age of 63.2 +/- 10.1 years, with no history of UBT. The incidence was 255 per 100,000. The median interval between transplantation and UBT was 60 months (range: 5 to 259 months). 72% of UBTs were stage pT > or = 1 and 63% were grade 3. CIS was present in 20% of cases. 25% of patients were N+. In addition to resection of the UBT, 3 patients were also treated with mitomycin C and 1 was treated with BCG. 7 patients underwent cystectomy, with a palliative objective in 42% of cases, associated with radiotherapy-chemotherapy (2/3) or chemotherapy alone (1/3). Immunosuppressive therapy was decreased in 50% of cases. Six patients (25%) died from bladder cancer, 25% relapsed with a tumour progression rate of 50%. 46% of patients were in remission of their UBT 4% died from an intercurrent cause. 76% of survivors have a Junctional graft with no alteration of serum creatinine. CONCLUSION: Renal transplant recipients have an increased incidence of UBT, which are more aggressive and associated with a higher mortality compared to the general population. Increased surveillance and aggressive treatment therefore appear to be justified.

[Urodynamic changes after transobturator suburethral tape]. / Modifications urodynamiques après pose d'une bandelette sous-urétrale trans-obturatrice.

INTRODUCTION: Prospective study of urodynamic changes induced by transobturator insertion of suburethral tape a dip-stick under-urethral. MATERIALS AND METHODS: 25 women with pure (12) or mixed (13) stress urinary incontinence were operated by this technique, allowing urodynamic assessment and completion of the MHU urinary disability questionnaire. Three operators performed these 25 tape insertions in 2 centres (Amiens and St Quentin hospitals) according to a standardized technique. Six months after the operation, patients were reviewed by clinical examination, MHU questionnaire and urodynamic assessment. RESULTS: The cure rate at 6 months was 80% (20 patients) and the improvement rate was 20% (5 patients). The maximum flow rate decreased from 23.6 ml/s to 18.9 ml/s (p = 0.02) and the post-voiding residual volume increased from 26.8 ml to 66.8 ml (p = 0.01). Urethral resistance increased from 0.16 to. 0.25 (p = 0.03) and maximum closure pressure increased from 43.8 to 47.5 cm H2O (p = 0.02). These results demonstrate the obstructive nature of this suburethral tape. The results of the MHU questionnaire showed accentuation of dysuria (p = 0.04) and improvement of stress urinary incontinence (p < 0.001). CONCLUSION: This prospective study confirms the efficacy of this technique, but analysis of the urodynamic studies and the MHU questionnaire demonstrates obstruction. Long-term surveillance of these patients by uroflowmetry and residual urine appears to be useful to detect possible progression to chronic urinary retention.

Cholesterol crystal embolization diagnosed on bladder transurethral resection.

Cholesterol crystal embolization (CCE) is a severe systemic disorder caused by vascular migration of cholesterol crystals originating from ulcerative atherosclerotic plaques located in large arteries. We report 2 cases of CCE diagnosed on bladder transurethral resection in 2 men aged 94 and 72 years. Both patients had atherosclerosis disease. One patient had been treated by heparin 1 month before for pulmonary embolism and the other had had a coronary angiography and bypass graft surgery 5 months before for silent myocardial infarction. One patient presented with hematuria and the other with acute renal failure. Cystoscopy showed multiple papillary tumors of the bladder wall. Bladder transurethral resections showed transitional cell carcinoma with cholesterol crystals occluding the lumen of small arterioles in the submucosa. Eight cases of CCE in the bladder wall have been reported in the literature in 3 women and 5 men aged 56 to 79 years. Cholesterol crystal embolization is often discovered in the bladder wall on necropsy specimens. Only 2 cases have been fortuitously discovered on bladder transurethral resection performed for transitional cell carcinoma. Cholesterol crystal embolization in the bladder wall is often a marker of severe disease although the evolution is quite favorable in our patients, still alive 1 and 2 years after diagnosis.

Spontaneous oscillatory activity of starburst amacrine cells in the mouse retina.

Using patch-clamp techniques, we investigated the characteristics of the spontaneous oscillatory activity displayed by starburst amacrine cells in the mouse retina. At a holding potential of -70 mV, oscillations appeared as spontaneous, rhythmic inward currents with a frequency of approximately 3.5 Hz and an average maximal amplitude of approximately 120 pA. Application of TEA, a potassium channel blocker, increased the amplitude of oscillatory currents by >70% but reduced their frequency by approximately 17%. The TEA effects did not appear to result from direct actions on starburst cells, but rather a modulation of their synaptic inputs. Oscillatory currents were inhibited by 6-cyano-7-nitroquinoxalene-2,3-dione (CNQX), an antagonist of AMPA/kainate receptors, indicating that they were dependent on a periodic glutamatergic input likely from presynaptic bipolar cells. The oscillations were also inhibited by the calcium channel blockers cadmium and nifedipine, suggesting that the glutamate release was calcium dependent. Application of AP4, an agonist of mGluR6 receptors on on-center bipolar cells, blocked the oscillatory currents in starburst cells. However, application of TEA overcame the AP4 blockade, suggesting that the periodic glutamate release from bipolar cells is intrinsic to the inner plexiform layer in that, under experimental conditions, it can occur independent of photoreceptor input. The GABA receptor antagonists picrotoxin and bicuculline enhanced the amplitude of oscillations in starburst cells prestimulated with TEA. Our results suggest that this enhancement was due to a reduction of a GABAergic feedback inhibition from amacrine cells to bipolar cells and the resultant increased glutamate release. Finally, we found that some ganglion cells and other types of amacrine cell also displayed rhythmic activity, suggesting that oscillatory behavior is expressed by a number of inner retinal neurons.

Assessment of Chlamydia trachomatis infection in asymptomatic male partners of infertile couples.

Three specimens from 111 asymptomatic male partners of infertile couples attending the Department of Urology in Amiens, France, were examined by the PCR COBAS AMPLICOR test (Roche Molecular Diagnostics) for the presence of Chlamydia trachomatis. The specimens analysed were: first void urine (FVU), urine obtained after prostatic massage (UPM) and semen specimens. Serum from each patient was also obtained and analysed for the presence of IgG and IgA chlamydial antibodies by in-house microimmunofluorescence (MIF) and pELISA. C. trachomatis was detected by PCR in 5.4% of FVU samples, 2.7% of semen specimens and in 0.9% of UPM samples. Two treatments for processing the samples (storage at -70 degrees C and heating to 95 degrees C) were routinely used before initial testing to reduce the effects of inhibitors of PCR. Despite these precautions, the PCR method revealed the presence of inhibitors in 7.3% of semen specimens and 3.6% of FVU samples. C. trachomatis was detected by PCR COBAS AMPLICOR in seven of 111 patients (6.3%) and by serology in five of 111 patients (4.5%). The detection of C. trachomatis in FVU, UPM and semen specimens can serve as a marker for the presence of this organism in the genital tract, and can be used as a reliable way of detecting asymptomatic carriers of infection.

A unique role for Kv3 voltage-gated potassium channels in starburst amacrine cell signaling in mouse retina.

Direction-selective retinal ganglion cells show an increased activity evoked by light stimuli moving in the preferred direction. This selectivity is governed by direction-selective inhibition from starburst amacrine cells occurring during stimulus movement in the opposite or null direction. To understand the intrinsic membrane properties of starburst cells responsible for direction-selective GABA release, we performed whole-cell recordings from starburst cells in mouse retina. Voltage-clamp recordings revealed prominent voltage-dependent K(+) currents. The currents were mostly blocked by 1 mm TEA, activated rapidly at voltages more positive than -20 mV, and deactivated quickly, properties reminiscent of the currents carried by the Kv3 subfamily of K+ channels. Immunoblots confirmed the presence of Kv3.1 and Kv3.2 proteins in retina and immunohistochemistry revealed their expression in starburst cell somata and dendrites. The Kv3-like current in starburst cells was absent in Kv3.1-Kv3.2 knock-out mice. Current-clamp recordings showed that the fast activation of the Kv3 channels provides a voltage-dependent shunt that limits depolarization of the soma to potentials more positive than -20 mV. This provides a mechanism likely to contribute to the electrical isolation of individual starburst cell dendrites, a property thought essential for direction selectivity. This function of Kv3 channels differs from that in other neurons where they facilitate high-frequency repetitive firing. Moreover, we found a gradient in the intensity of Kv3.1b immunolabeling favoring proximal regions of starburst cells. We hypothesize that this Kv3 channel gradient contributes to the preference for centrifugal signal flow in dendrites underlying direction-selective GABA release from starburst amacrine cells