Novel Platforms for Biomedical HIV Prevention Delivery to Key Populations - Community Mobile Clinics, Peer-Supported, Pharmacy-Led PrEP Delivery, and the Use of Telemedicine.

PURPOSE OF REVIEW: A gap exists between PrEP interest and PrEP uptake in key populations (KP) for HIV prevention that may be ascribed to PrEP delivery services not being acceptable. This review summarizes novel platforms for HIV prevention outside of the traditional health facilities environment. RECENT FINDINGS: Mobile health clinics provide highly acceptable integrated, KP-focused services at convenient locations with the potential of high PrEP uptake. Telemedicine and health apps decongest health systems and allow for personal agency and informed decision-making on personal health. Pharmacy-led PrEP delivery provides de-medicalized, confidential PrEP services at extended hours in community locations, from trusted medical professionals. Peer-supported delivery encourages continued PrEP use. Community-based, differentiated and de-medicalized PrEP delivery can address uptake and continued use barriers in key populations. Future research should assess scalability, cost-effectiveness and sustainability of these PrEP delivery platforms, as well as focus on ways to simplify PrEP provision.

[Treatment of submacular hematoma by vitrectomy, subretinal injection of rtPA and gaseous tamponade: A single-center retrospective observational study]. / Traitement des hématomes sous-maculaires par vitrectomie, injection sous-rétinienne de rtPA et tamponnement gazeux : une étude observationnelle rétrospective monocentrique.

OBJECTIVES: To evaluate the functional and anatomic recovery of submacular hemorrhage (SMH), treated with vitrectomy, subretinal injection of rtPA and gas tamponade, to highlight the risk factors for their occurrence as well as the factors influencing prognosis. MATERIALS AND METHODS: This is a single-center retrospective study. Thirty-two eyes of 30 patients from the Clermont-Ferrand University Hospital were included, with a submacular hemorrhage (SMH) requiring surgical evacuation. The primary endpoint was final postoperative visual recovery. Visual acuities (AV) were converted to the logarithmic minimum angle of resolution scale (logMAR) for statistical analysis. RESULTS: The average time from onset of symptoms to surgery was 4.8±3.3 days. The initial VA was 2.1±0.3 logMAR, with an average improvement of 0.7±0.7 logMAR (P=0.0004) at the final visit. The mean thickness of the SMH decreased by 729±352µm (P<0.0001) at the final visit. CONCLUSION: Treatment of SMH with vitrectomy, subretinal injection of rtPA and gas tamponade results in a statistically significant improvement in final VA, as well as a significant decrease in SMH thickness on OCT.

Cleaning patch-clamp pipettes for immediate reuse.

Patch-clamp recording has enabled single-cell electrical, morphological and genetic studies at unparalleled resolution. Yet it remains a laborious and low-throughput technique, making it largely impractical for large-scale measurements such as cell type and connectivity characterization of neurons in the brain. Specifically, the technique is critically limited by the ubiquitous practice of manually replacing patch-clamp pipettes after each recording. To circumvent this limitation, we developed a simple, fast, and automated method for cleaning glass pipette electrodes that enables their reuse within one minute. By immersing pipette tips into Alconox, a commercially-available detergent, followed by rinsing, we were able to reuse pipettes 10 times with no degradation in signal fidelity, in experimental preparations ranging from human embryonic kidney cells to neurons in culture, slices, and in vivo. Undetectable trace amounts of Alconox remaining in the pipette after cleaning did not affect ion channel pharmacology. We demonstrate the utility of pipette cleaning by developing the first robot to perform sequential patch-clamp recordings in cell culture and in vivo without a human operator.

Galectin-3 inhibition prevents adipose tissue remodelling in obesity.

Extracellular matrix remodelling of the adipose tissue has a pivotal role in the pathophysiology of obesity. Galectin-3 (Gal-3) is increased in obesity and mediates inflammation and fibrosis in the cardiovascular system. However, the effects of Gal-3 on adipose tissue remodelling associated with obesity remain unclear. Male Wistar rats were fed either a high-fat diet (33.5% fat) or a standard diet (3.5% fat) for 6 weeks. Half of the animals of each group were treated with the pharmacological inhibitor of Gal-3, modified citrus pectin (MCP; 100 mg kg(-1) per day) in the drinking water. In adipose tissue, obese animals presented an increase in Gal-3 levels that were accompanied by an increase in pericellular collagen. Obese rats exhibited higher adipose tissue inflammation, as well as enhanced differentiation degree of the adipocytes. Treatment with MCP prevented all the above effects. In mature 3T3-L1 adipocytes, Gal-3 (10(-8 )m) treatment increased fibrosis, inflammatory and differentiation markers. In conclusion, Gal-3 emerges as a potential therapeutic target in adipose tissue remodelling associated with obesity and could have an important role in the development of metabolic alterations associated with obesity.

[Ocular involvement with Candida albicans: report of 2 cases]. / Atteinte oculaire à Candida albicans : à propos de 2 cas.

INTRODUCTION: Ocular involvement by Candida albicans is rare and may present as endogenous endophthalmitis or choroiditis. It occurs in the context of C. albicans septicemia, in the context of intensive care unit hospitalization or intravenous drug use. We report two cases referred to our department with different characteristics, background, diagnostic modalities and different courses. OBSERVATIONS: A 37-year-old woman, with a history of intravenous drug use, presented with C. albicans endophthalmitis. Intravenous combination antifungal therapy was begun, but vitrectomy and intravitreal amphotericin B were performed due to worsening of the endophthalmitis. The second case was a 53-year-old man who was hospitalized in the intensive care unit for C. albicans septicemia with a left macular chorioretinitis. Intravenous antifungal therapy was initiated and allowed regression of the ocular lesion. DISCUSSION: Our cases illustrate both types of ophthalmic involvement by candidiasis requiring different treatments with well-described recommendations: in the case of endophthalmitis, the use of vitrectomy and intravitreal amphotericin B injection in association with intravenous antifungal treatment, whereas parenteral antifungal treatment is often sufficient in the case of chorioretinitis. CONCLUSION: Early detection, initiation of treatment and ophthalmologic monitoring are difficult but necessary in these populations non-compliant with follow-up or in intensive care units. The management of ocular candidiasis requires good collaboration between the ophthalmology, infectious diseases and intensive care unit departments.

[Male breast cancer: prognostic factors, diagnosis and treatment: a multi-institutional survey of 95 cases]. / Le cancer du sein chez l'homme: approche épidémiologique, diagnostique, et thérapeutique: étude multicentrique rétrospective à propos de 95 cas.

OBJECTIVES: The optimal treatment for male breast cancer is not known because male breast cancer is a rare disease. It represents as little as 0.6% of all breast cancers and less than 1% of human cancers. The aim was to analyze the clinical, histological and therapeutic characteristics of 95 men cared for breast cancer between 2000 and 2010 in four hospitals, and determine predictors of poor prognosis to improve care of male breast cancer. METHODS: This study is a multi-institutional survey, retrospective, involving four French institutions: Cancer Institute of the West (ICO), Reunion Island South hospital group, the hospital group of Dax, and the Bergonié Institute. All carcinomas in situ or invasive breast occurred in male patients were included. An analysis of clinical, histological and therapeutic features was performed. Statistical analysis of our study focused on the overall survival of patients and specific method of Kaplan-Meier, enabling search for predictors of poor prognosis. RESULTS: The mean age was 65 years. Thirty-seven percent of patients were overweight or obese. It was in 88% of cases of palpable tumor whose average size was 26.29mm. Ninety patients, none had a lesion palpable T0, 44% T1 tumors, 38% T2 tumors, 3% had a T3 tumors, and finally 10% T4 tumors. The histological type was the most common invasive ductal carcinoma (87%). He found a similar proportion of patients with or without lymph node involvement. N+ patients, capsular rupture was observed in 29% of cases. Receptor positivity was found, estrogen in 95% of cases and progesterone in 83% of cases. Additional irradiation was performed in 75% of patients and chemotherapy in 37% of patients. Overall survival was 79.2% at five years and 70.8% at ten years. Age, tumor size and histological capsular rupture are factors that significantly influence the overall survival and specific. CONCLUSION: Male breast cancer is a different pathology of breast cancer in women. The majority of recommendations suggest treating men who are diagnosed with breast cancer, using the guidelines applied to postmenopausal women treatments. There is no study based on male population that has evaluated these treatment modalities in terms of impact on survival. The diagnosis is usually made at later stages, and tumor size is often greater. Histological characteristics also differ. However, the treatment is almost identical.

Fibrosis of the thyroid gland caused by an IgG4-related sclerosing disease: three years of follow-up.

Immunoglobulin G4-related sclerosing disease (IgG4-RSD) represents a recently identified inflammatory disorder in which infiltration of IgG4 plasma cells causes fibrosis in organs. While IgG4-RSD is well documented in the pancreas and other organs, it is poorly characterized in the thyroid gland. We report a case of a 48-year-old female with a fibrotic thyroid mass associated with a retroperitoneal fibrosis. Diagnosed early as Riedel disease, the high serum IgG4, immunohistopathology and decreased fibrosis with corticosteroid therapy, finally confirm for the first time, the origin of IgG4-RSD fibrosis of the thyroid.

MAG-EPA resolves lung inflammation in an allergic model of asthma.

BACKGROUND: Asthma is a chronic disease characterized by airways hyperresponsiveness, inflammation and airways remodelling involving reversible bronchial obstruction. Omega-3 fatty acids and their derivatives are known to reduce inflammation in several tissues including lung. OBJECTIVES: The effects of eicosapentaenoic acid monoacylglyceride (MAG-EPA), a newly synthesized EPA derivative, were determined on the resolution of lung inflammation and airway hyperresponsiveness in an in vivo model of allergic asthma. METHODS: Ovalbumin (OVA)-sensitized guinea-pigs were treated or not with MAG-EPA administered per os. Isometric tension measurements, histological analyses, homogenate preparation for Western blot experiments or total RNA extraction for RT-PCR were performed to assess the effect of MAG-EPA treatments. RESULTS: Mechanical tension measurements revealed that oral MAG-EPA treatments reduced methacholine (MCh)-induced bronchial hyperresponsiveness in OVA-sensitized guinea-pigs. Moreover, MAG-EPA treatments also decreased Ca(2+) hypersensitivity of bronchial smooth muscle. Histological analyses and leucocyte counts in bronchoalveolar lavages revealed that oral MAG-EPA treatments led to less inflammatory cell recruitment in the lung of OVA-sensitized guinea-pigs when compared with lungs from control animals. Results also revealed a reduction in mucin production and MUC5AC expression level in OVA-sensitized animals treated with MAG-EPA. Following MAG-EPA treatments, the transcript levels of pro-inflammatory markers such as IL-5, eotaxin, IL-13 and IL-4 were markedly reduced. Moreover, per os MAG-EPA administrations reduced COX2 over-expression in OVA-sensitized animals. CONCLUSION AND CLINICAL RELEVANCE: We demonstrate that MAG-EPA reduces airway hyperresponsiveness and lung inflammation in OVA-sensitized animals, a finding consistent with a decrease in IL-4, IL-5, IL-13, COX-2 and MUC5AC expression levels in the lung. The present data suggest that MAG-EPA represents a new potential therapeutic strategy for resolving inflammation in allergic asthma.

[A case report of syphilitic uveitis and deafness]. / Uvéite syphilitique et surdité : à propos d'un cas.

We report the case of a 43-year-old male patient presenting for neuro-ophthalmologic and uveitis consultation at Clermont-Ferrand University Medical Center for a reduction in visual acuity in his right eye. Two months previously, the patient had complained of decreased hearing on the left, which remained undiagnosed. Fundus examination and fluorescein angiogram showed the appearance of vasculitis with papillitis and a choroidal plaque. TPHA-VDRL serology was positive in blood and cerebrospinal fluid. Internal medicine work-up revealed many associated abnormalities: hyperhomocysteinemia, positive anticardiolipin antibody, positive anti-ß2GP1 antibodies, increased partial thromboplastin time not corrected by the addition of control plasma, presence of an anti-prothrombinase antibody, positive activated protein C resistance. ENT examination showed a left harmonic vestibular syndrome; audiography showed a sensorineural hearing loss of -40 dB. The patient received treatment for neurosyphilis, which led to the disappearance of the vasculitis, the choroidal plaque and the papillitis. From an ENT standpoint, the vestibular syndrome and the left vestibular areflexia resolved. The audiogram improved, with persistence of left hearing loss (about -20 dB) with useful speech intelligibility. Immunologic abnormalities had also disappeared. Our case illustrates the protean presentations of syphilis and its possible association with sensorineural deafness and immunological abnormalities.

Detection of a biexciton in semiconducting carbon nanotubes using nonlinear optical spectroscopy.

We report the observation of the biexciton in semiconducting single-wall carbon nanotubes by means of nonlinear optical spectroscopy. Our measurements reveal the universal asymmetric line shape of the Fano resonance intrinsic to the biexciton transition. For nanotubes of the (9,7) chirality, we find a biexciton binding energy of 106 meV. From the calculation of the χ((3)) nonlinear response, we provide a quantitative interpretation of our measurements, leading to an estimation of the characteristic Fano factor q of 7 ± 3. This value allows us to extract the first experimental information on the biexciton stability and we obtain a biexciton annihilation rate comparable to the exciton-exciton annihilation one.

[Unilateral uveitis with HHV6-positive polymerase chain reaction in aqueous humor for an etanercept-treated woman: a case report]. / Uvéite unilatérale avec polymerase chain reaction positive pour HHV6 dans l'humeur aqueuse chez une patiente sous étanercept: à propos d'un cas.

Human herpesvirus 6 is a ubiquitous Herpesviridae infecting patients during childhood. Its role in ocular disorders is mostly unknown. We report the case of a 47-year-old woman with a history of rheumatoid arthritis (treated with etanercept) and tuberculosis, who presented with sudden unilateral panuveitis. The patient was initially treated with ganciclovir, as the polymerase chain reaction in the aqueous humor was positive for HHV6, and with pyrimethamine and sulfadiazine because a toxoplasmic co-infection was highly suspected, which was biologically confirmed. Management of HHV6 in a nervous system disorder is challenging because its replication has been proved but its role remains unclear. HHV6 may be pathogenic by itself but can facilitate co-infection as can etanercept.

Mesoscopic description of radiative heat transfer at the nanoscale.

We present a formulation of the nanoscale radiative heat transfer using concepts of mesoscopic physics. We introduce the analog of the Sharvin conductance using the quantum of thermal conductance. The formalism provides a convenient framework to analyze the physics of radiative heat transfer at the nanoscale. Finally, we propose a radiative heat transfer experiment in the regime of quantized conductance.

Signalling pathways involved in the contractile response to 5-HT in the human pulmonary artery.

Serotonin (5-hydroxytryptamine; 5-HT) is a potent pulmonary vasoconstrictor and mitogenic agent whose plasma level is increased in pulmonary hypertensive patients. Thus, we explored the signalling pathways involved in the contractile response to 5-HT in human pulmonary arteries (HPAs). Intact and beta-escin permeabilised rings from HPAs mounted in an organ bath system were used to assess both tension and myofilament Ca(2+)-sensitisation. Microspectrofluorimetry was used for intracellular Ca(2+) recordings in cultured HPA smooth muscle cells. Voltage-operated Ca(2+) channel blockers (nitrendipine and nifedipine) partially reduced the contraction to 5-HT. Thapsigargin or cyclopiazonic acid (CPA), known to deplete sarcoplasmic reticulum Ca(2+) stores, also partially inhibited the contraction, whereas removal of extracellular Ca(2+) under these conditions further inhibited the contraction. Changing from Ca(2+)-free to Ca(2+) containing solution, in the presence of nitrendipine and CPA, a protocol known to stimulate store-operated Ca(2+) channels, induced HPA contractions that were blocked by nickel. Nickel or gadolinium also reduced the contraction to 5-HT. Finally, 5-HT increased intracellular Ca(2+) responses in cultured HPA smooth muscle cells and myofilament Ca(2+)-sensitisation in HPA rings. Collectively, these results indicate that voltage-operated and voltage-independent Ca(2+) channels, as well as Ca(2+) release and myofilament Ca(2+)-sensitisation, participate in 5-HT-induced contraction in HPAs.

Microarray profiling of isolated abdominal subcutaneous adipocytes from obese vs non-obese Pima Indians: increased expression of inflammation-related genes.

AIMS/HYPOTHESIS: Obesity increases the risk of developing major diseases such as diabetes and cardiovascular disease. Adipose tissue, particularly adipocytes, may play a major role in the development of obesity and its comorbidities. The aim of this study was to characterise, in adipocytes from obese people, the most differentially expressed genes that might be relevant to the development of obesity. METHODS: We carried out microarray gene profiling of isolated abdominal subcutaneous adipocytes from 20 non-obese (BMI 25+/-3 kg/m2) and 19 obese (BMI 55+/-8 kg/m2) non-diabetic Pima Indians using Affymetrix HG-U95 GeneChip arrays. After data analyses, we measured the transcript levels of selected genes based on their biological functions and chromosomal positions using quantitative real-time PCR. RESULTS: The most differentially expressed genes in adipocytes of obese individuals consisted of 433 upregulated and 244 downregulated genes. Of these, 410 genes could be classified into 20 functional Gene Ontology categories. The analyses indicated that the inflammation/immune response category was over-represented, and that most inflammation-related genes were upregulated in adipocytes of obese subjects. Quantitative real-time PCR confirmed the transcriptional upregulation of representative inflammation-related genes (CCL2 and CCL3) encoding the chemokines monocyte chemoattractant protein-1 and macrophage inflammatory protein 1alpha. The differential expression levels of eight positional candidate genes, including inflammation-related THY1 and C1QTNF5, were also confirmed. These genes are located on chromosome 11q22-q24, a region with linkage to obesity in the Pima Indians. CONCLUSIONS/INTERPRETATION: This study provides evidence supporting the active role of mature adipocytes in obesity-related inflammation. It also provides potential candidate genes for susceptibility to obesity.

Increased expression of inflammation-related genes in cultured preadipocytes/stromal vascular cells from obese compared with non-obese Pima Indians.

AIMS/HYPOTHESIS: The specific contributions made by the various cell types in adipose tissue to obesity, particularly obesity-related inflammation, need to be clarified. The aim of this study was to elucidate the potential role of adipocyte precursor cells (preadipocytes/stromal vascular cells [SVC]). METHODS: We performed Affymetrix oligonucleotide microarray expression profiling of cultured abdominal subcutaneous preadipocytes/SVC isolated from the adipose tissue of 14 non-obese (BMI 25+/-4 kg/m2) and 14 obese (55+/-8 kg/m2) non-diabetic Pima Indian subjects. Quantitative real-time PCR (RT-PCR) was used to verify the differential expression of several genes in an independent group of subjects. RESULTS: We identified 218 differentially expressed genes with p values less than 0.01. Microarray expression profiling revealed that the expression of inflammation-related genes was significantly upregulated in preadipocytes/SVC of obese individuals. Quantitative RT-PCR confirmed the upregulation of IL8, CTSS, ITGB2, HLA-DRA, CD53, PLA2G7 and MMP9 in preadipocytes/SVC of obese subjects. CONCLUSIONS/INTERPRETATION: The upregulation of inflammation-related genes in preadipocytes/SVC of obese subjects may increase the recruitment of immune cells into adipose tissue and may also result in changes in the extracellular matrix (tissue remodelling) to accommodate adipose tissue expansion in obesity.

Capsazepine, a vanilloid antagonist, abolishes tonic responses induced by 20-HETE on guinea pig airway smooth muscle.

The aim of this study was to delineate the mode of action of 20-hydroxy-eicosatetraenoic acid (20-HETE) in airway smooth muscle (ASM) cells. ASM metabolizes arachidonic acid by various enzymatic pathways, including the cytochrome P-450 (CYP-450) omega-hydroxylase, which leads to the production of 20-HETE, a bronchoconstrictive eicosanoid. The present study demonstrated that 20-HETE induced concentration-dependent tonic responses in ASM, whereas transient responses were recorded in Ca2+-free solution, suggesting an intracellular Ca2+ release process. 20-HETE inotropic responses were abolished by 36 microM 2-aminoethoxydiphenyl borate or 1 microM thapsigargin but were insensitive to 10 microM ryanodine, indicating that inositol triphosphate receptors likely control the release of intracellular Ca2+. Sustained tension, which required Ca2+ entry, was partially blocked by 1 microM nifedipine (an L-type) and 100 microM Gd3+ (a nonselective cationic channel blocker). Moreover, in the absence of selective 20-HETE receptor antagonists, 20-HETE tonic responses were inhibited in a concentration-dependent manner (0.1-10 microM) by capsazepine, a well-characterized vanilloid receptor antagonist. Capsazepine was also observed to reverse cumulative responses to 20-HETE and capsaicin, a TRPV1 agonist. In addition, capsazepine pretreatment largely modified the sustained inotropic responses to 20-HETE, suggesting that 20-HETE cross-reacted with TRPV1 receptors with a low affinity (microM) or that its specific receptor was inhibited by the vanilloid antagonist. Data obtained using RHC-80267, ONO-RS-082, and eicosatetraynoic acid, respective inhibitors of diacylglycerol-lipase, phospholipase A2, and CYP-450 omega-hydroxylase, reveal that intracellular arachidonic acid production and its 20-HETE metabolite may be responsible for the activation of nonselective cationic channels and tonic responses.

CDKN2A, CDKN2B and p14ARF are frequently and differentially methylated in ependymal tumours.

Ependymal tumours are histologically and clinically varied lesions. Numerical abnormalities of chromosome 9 are frequently associated with these tumours. Nevertheless, the three important tumour suppressor genes located in this chromosome, CDKN2A, CDKN2B and p14 ARF, have not been reported to be commonly altered in them. We studied promoter methylation of these genes, an important mechanism associated with gene silencing in a series of 152 ependymal tumours of WHO grades I to III. Methylation status of the CDKN2A, CDKN2B and p14 ARF promoters was assessed by methylation-specific polymerase chain reaction and the genetic results were correlated to clinicopathological features. We observed promoter methylation for CDKN2A in 21% (26/123) of tumours, for CDKN2B in 32% (23/71) and p14 ARF in 21% (23/108). For all three genes, posterior fossa ependymomas were less frequently methylated in paediatric patients than in adults. For CDKN2B, extracranial tumours were more frequently methylated than intracranial ones. For CDKN2B and p14 ARF, methylation was more frequent in low-grade tumours; the reverse was observed for CDKN2A. CDKN2A, CDKN2B and p14 ARF promoters were methylated in 21-32% of the tumours. Frequencies of methylation varied according to clinicopathological features. This suggests a role for these genes in ependymoma tumorigenesis.

Tumour necrosis and microvascular proliferation are associated with 9p deletion and CDKN2A alterations in 1p/19q-deleted oligodendrogliomas.

A subset of oligodendrogliomas and oligoastrocytomas has been associated with 1p/19q deletion. Subsequently, this genetic alteration was linked to chemosensitivity and classic histology of oligodendrogliomas. Tumoural progression includes deletions of 9p, 10q and alterations of CDKN2A. However, these (epi)genetic changes have not been associated with specific histological features. In a series of 45 gliomas including oligodendrogliomas, oligoastrocytomas and astrocytomas, deletions of chromosomal regions implied in these tumours (1p, 9p, 10, 17p13, 19q and 22) were looked for by microsatellite analysis. Tumours that were deleted for 1p and 19q were selected. Subsequently, presence of deletions in the other studied regions, (epi)genetic changes in p14ARF, CDKN2A and CDKN2B, as well as histological features, were associated to these tumours. 1p/19q deletion was observed in 22 tumours. Twenty-one of them presented regions of classic histology of oligodendroglioma. A deletion of 9p was found in eight of them, always in association with tumour necrosis and/or microvascular proliferation. In addition, (epi)genetic alterations of CDKN2A were observed in 71% of these tumours. Presence of regions of classic histology of oligodendroglioma in a tumour sample is predictive of 1p/19q deletions. Necrosis and/or microvascular proliferation are signs of an additional 9p deletion. Finally, as CDKN2A (epi)genetic alterations were found in 71% of the 1p/19q/9p-deleted oligodendrogliomas, CDKN2A may have a role in oligodendroglioma-associated microvascular proliferation.

[Surgical treatment of genital prolapse with a new lateral prosthetic hysteropexia technique combining vaginal and laparoscopic methods]. / Traitement chirurgical du prolapsus génital par une nouvelle technique d'hystéropexie latérale prothétique combinant voie vaginale et coelioscopique.

We describe a new surgical treatment of pelvic organ prolapse. The anterior and medium compartments are treated by a transversal hysteropexy by means of an anterior prosthesis fixed by vaginal route and by laparoscopy. The principle is based on the operative technique described by Kapandji but the prosthesis is fixed to the fascia of the external oblique muscle in a subperitoneal path. The posterior compartment is treated by a vaginal route exclusively. A posterior prosthesis is placed in the rectovaginal space and fixed to the elevator muscles. Further studies are necessary to evaluate this new operative technique.

Effect of sildenafil on cyclic nucleotide phosphodiesterase activity, vascular tone and calcium signaling in rat pulmonary artery.

(1) Sildenafil (viagra) is a potent PDE5 inhibitor and thus a relaxant drug in corpus carvernosum smooth muscle. In the present work, we evidenced the presence of PDE5 isozyme and investigated the effect of sildenafil on the specific cyclic nucleotide phosphodiesterase (PDE) activity, smooth muscle tone and calcium signaling in the rat main pulmonary artery (MPA). (2) The PDE activity was measured in cytosolic and microsomal fractions. Total cAMP and cGMP-PDE activities were mainly present in the cytosolic fraction. Sildenafil (0.1 micro M) reduced by 72% cGMP-PDE activity, whereas zaprinast (10 micro M), a relatively selective PDE5 inhibitor, reduced this activity by 63%. Sildenafil (0.1 micro M) also inhibited significantly (22%) the cAMP-PDE activity. (3) Western blot analysis revealed the expression of PDE5 mainly in the cytosolic fraction of MPA. Sildenafil concentration-dependently inhibited (IC(50)=3.4 nM) the activity of MPA PDE5 partially purified by HPLC. (4) Sildenafil (0.1 nM-50 micro M) concentration-dependently relaxed MPA rings precontracted with phenylephrine (0.5 micro M). The potency of sildenafil (IC(50)=11 nM) was similar to that of a nitric oxide donor, sodium nitroprusside, but higher than that of zaprinast (IC(50)=600 nM). The vasorelaxant effect of sildenafil was not altered by endothelium removal or in the presence of KT 5823 (1 micro M) and H89 (1 micro M), potent inhibitors of PKG and PKA, respectively. (5) In isolated MPA myocytes, which had been loaded with the calcium fluorophore indo-1, sildenafil (10-100 nM) antagonized ATP- and endothelin-1-induced calcium oscillations but had no effect on the transient caffeine-induced [Ca(2+)](i) response. (6) This study demonstrates the presence of a functional and highly sildenafil-sensitive PDE5 isozyme in rat MPA. Inhibition of this isozyme mainly accounts for the potent pulmonary vasodilator action of sildenafil, which involves alteration in the inositol triphosphate-mediated calcium signaling pathway.