Search

Purpose of review To review current surgical practices of lower eyelid reconstruction with a focus on recent studies. Recent findings Combination techniques and new flap techniques offer efficacy comparable with existing reconstructive approaches, with the advantage of less local trauma. Inappropriate handling of posterior lamellar grafts, such as kerfing, may predispose to graft failures. Modified Hughes procedure is a favorable choice for large lower eyelid reconstruction; however, it requires temporary eye closure. Other surgical options have been developed to achieve a 1-stage procedure without the need of eye closure. These include the Smith-modified Kuhnt-Szymanowski procedure and the use of flaps. For posterior lamellar grafts, both nasal septal and ear cartilage donor tissue produce esthetically and functionally satisfactory outcomes and comparable efficacy. However, the ear cartilage carries a lower risk of donor site complications. Summary Lower eyelid reconstruction remains a challenge, especially for large or near total defects. Recent studies have explored modifications and alternatives to the conventional Hughes flap. New surgical procedures give surgeons more options. Taking into account the growing spectrum of reconstructive techniques, an individualized approach may facilitate better functional and esthetic outcomes.

Introduction: Diabetes mellitus is associated with impaired cavernosal smooth muscle relaxation (CSMR) and the development of erectile dysfunction (ED). Vardenafil, a phosphodiesterase type 5 inhibitor has been used to treat ED. The aim of this study was to assess the in vitro and in vivo effects of vardenafil on diabetic rabbit CSMR. Methods: Organ bath studies were used. Results: Sodium nitroprusside (SNP)- and electrical field stimulation (EFS)-induced CSMR in diabetic rabbits given the vehicle was significantly impaired when compared with controls. The in vitro addition of vardenafil significantly enhanced SNP-induced CSMR in diabetic animals given the vehicle. SNP-induced CSMR in diabetic animals given in vivo vardenafil was significantly increased when compared with the diabetic untreated group. The in vitro addition of vardenafil significantly enhanced SNP and EFS-induced CSMR in cavernosal tissue taken from diabetic animals given vardenafil in vivo. Conclusions: The present findings suggest that the combination of in vitro and in vivo vardenafil enhance diabetic CSMR, reinforcing the use of vardenafil for the treatment of diabetes-induced ED.

SnO2 nanorods were successfully deposited on substrate by inductively coupled plasma-enhanced chemical vapor deposition (PECVD) using dibutyltin diacetate (DBTDA) as the precursor. Each of the SnO2 nanorods in situ grown under catalyst- and template-free growth condition and without any substrate heating was found to be [110] oriented single crystal. These needle-shaped nanorods have an average diameter between 5 and 16 nm and a length of 160 to 250 nm from TEM observation. Substrate distance and RF power showed notable effects on the formation of SnO2 nanorods.

Introduction: Serotonin (5-hydroxytryptamine; 5-HT) can cause contraction in cavernosal smooth muscle. We further evaluated this effect of 5-HT. Methods: Organ bath studies were used. Results: 5-HT induced a sustained contraction occasionally accompanied by a transient relaxation (in 30% of rabbit cavernosal tissues) that preceded the contraction. Ondansetron and Y-25130 (both 5-HT3 receptor antagonists) but not SB-269970 (a 5-HT7 receptor antagonist) significantly inhibited or abolished this transient relaxation. Doxazosin (dox, an α1-receptor antagonist) and ketanserin (ketan, a 5-HT2A receptor antagonist) significantly inhibited or abolished the sustained contraction. The effects of dox on 5-HT-mediated contraction were concentration-dependent. Conclusions: Our findings further confirm that the peripheral serotonergic pathway may play a part in the erectile process via 5-HT2A receptor-mediated contractile and 5-HT3 receptor-mediated relaxant activities. Our results also support the findings of human studies, which suggest that both ketan and dox may exert beneficial effects on the erectile process.

The oral phosphodiesterase type 5 (PDE5) inhibitors have made a valuable contribution to the treatment of erectile dysfunction (ED). PDE5 inhibitors enhance cavernosal smooth muscle relaxation, vasodilatation and penile erection. However, PDE5 inhibitors are not always effective. Decreased efficacy, cost, incorrect administration, lack of sexual stimulation, vascular risk factors associated with ED and vascular or neurogenic diseases are causes of PDE5 inhibitor failure. Tachyphylaxis may also occur. This is defined as reduced tissue responsiveness to a drug in the presence of a constant concentration of this drug. Treatment failure may cause considerable distress. If dose titration, more attempts and continuous dosing of PDE5 inhibitors (taken on a daily basis) fail to resolve the initial PDE5 inhibitor failure, clinicians need to consider alternative treatments. These include sublingual apomorphine, intracavernosal/intraurethral pharmacotherapy, vacuum devices, the insertion of a prosthesis and penile vascular surgery. Combination therapy like prostaglandin E(1) (PGE(1)) with doxazosin (dox; an alpha-1-blocker) or ketanserin (ketan; a 5-HT(2) antagonist) as well as other pro-erection agents, like Endothelin-1 antagonists, angiotensin II antagonists (valsartan/losartan), adrenomedullin, Rho kinase inhibitors and nitric oxide (NO) donors may be beneficial in the treatment of ED. However, these combination therapies need to be validated. Adding an androgen to a PDE5 inhibitor may help when circulatory testosterone levels are low. The early use of PDE5 inhibitors in patients with hypertension, hyperlipidaemia or diabetes with concomitant ED and treating these risk factors may improve corporeal blood flow and lead to long-term preservation of cavernosal function. Therefore, the efficacy of PDE5 inhibitors may be maintained. Targeting the risk factors of ED (similar to those for arteriosclerosis) in the early stages of the disease may prevent the development or decrease the severity of ED.

Introduction We investigated the effect angiotensin II (Ang II), a corpus cavernosal smooth muscle (CCSM) constrictor peptide, has on tissue taken from rabbits following chronic partial bladder outlet obstruction (PBOO), as this model is characterized by an increase in corpus cavernosal collagen deposition and a marked reduction and impaired relaxation of CCSM cells. Aim To determine the interaction between Ang II and nitric oxide (NO) and the development of oxidative stress (OS) in a rabbit model of chronic PBOO. Methods Corpus cavernosal tissue was obtained from 12 sham‐operated and 20 PBOO rabbits. Organ bath studies determined Ang II/NO interaction on CCSM function using losartan (AT1 receptor antagonist), sodium nitroprusside (SNP, NO donor), electrical field stimulation (EFS), and vardenafil (phosphodiesterase type 5 inhibitor). The role of OS in the Ang II response was also determined using diphenylene iodonium chloride (DPI), the nicotinamide adenine dinucleotide phosphate oxidase inhibitor, which inhibits superoxide production and superoxide dismutase (SOD, the enzyme that accelerates the breakdown of superoxide). Main Outcome Measure Action of Ang II and AT1 receptor antagonist, as well as SOD and DPI on CCSM function. Results Ang II caused a dose‐dependent contraction of CCSM strips that was enhanced in PBOO rabbits and inhibited by losartan, DPI, and SOD. CCSM relaxation induced by SNP/EFS was impaired in this model and improved by vardenafil and losartan. Conclusions These findings imply that the increased Ang II contractile response is a pathological consequence of PBOO and that AT1 receptor inhibition may be a therapeutic approach to treat ED associated with PBOO.

The unique synthesis of solid-state reaction silicon nanocrystals (Si nc) is reported. Different sizes of Si nc have been synthesized using mechanical milling at different milling hours. Using x-ray diffraction and Scherrer's equation, the sizes of the Si nc synthesized are calculated to range from 10 nm to 25 nm. Transmission electron microscopic (TEM) images further verified the size derived from the diffraction results. These Si nc are also characterized using differential thermal analysis (DTA), raman scattering and infrared absorption. DTA and raman scattering reveals no amorphous Si content. At the same time, infrared absorption shows no trace of Si-H and Si-OH bonds. Further reduction of these solid-state reaction Si nc can be achieved by oxidation. 3 hours of annealing is capable of reducing Si nc from 12 nm to 8 nm. Self-limiting oxidation is experienced after 2 hours of oxidation which deters further size reduction.

SnO 2 nanorods were successfully deposited on SiO 2 /Si substrate by inductively coupled plasma-enhanced chemical vapor deposition (PECVD) using dibutyltin diacetate (DBTDA) as the precursor. The SnO 2 nanorods were in situ grown without additional substrate heating. These nanorods have an average diameter between 19 and 27 nm and a length of 190 to 600 nm depending on the deposition parameters. Substrate distance and RF power showed notable effects on the formation of SnO 2 nanorods. These high surface area SnO 2 nanorods showed sensing properties to reducing gases like CO.

Research has led to effective treatment regimes for erectile dysfunction (ED). Convincing evidence links vascular risk factors (hypertension, diabetes mellitus, hyperlipidaemia and smoking) with ED. This association is not surprising since the corpus cavernosum is a modified vascular tissue. This review presents a brief account of the aetiology, diagnosis and treatment of ED. There is a need to raise awareness of this condition and to make appropriate treatment available to patients.

The contribution of specific genes on the Y chromosome in the etiology of prostate cancer has been undefined. Genetic mapping studies have identified a gonadoblastoma locus on the human Y chromosome (GBY) that predisposes the dysgenetic gonads of XY sex-reversed patients to tumorigenesis. Recently a candidate gene, the testis-specific protein Y-encoded (TSPY) that resides on the GBY critical region, has been demonstrated to express preferentially in tumor cells in gonadoblastoma and testicular germ cell tumors. TSPY shares high homology to a family of cyclin B binding proteins and has been considered to possibly play a role in cell cycle regulation or cell division. To address the possible involvement of the TSPY gene in prostate cancer, both in situ mRNA hybridization and immunohistochemistry techniques were used to study the expression of this putative GBY gene in prostate specimens. Our results demonstrated that TSPY was expressed at low levels in normal epithelial cells and benign prostatic hyperplasia (BPH), but at elevated levels in tumor cells of prostate cancers at various degrees of malignancy. Sequence analysis of RT-PCR products obtained from both prostatic and testicular tissues using specific primers flanking the open reading frame of the TSPY mRNA revealed a complex pattern of RNA processing of the TSPY transcripts involving cryptic intron splicing and/or intron skipping. The variant transcripts encode a variety of polymorphic isoforms or shortened versions of the TSPY protein, some of which might possess different biochemical and/or functional properties. The abbreviated transcripts were more abundant in prostatic cancer tissues than the testicular ones. Although the exact nature of such variant TSPY transcripts and proteins is still unclear, their differential expression suggests that the TSPY gene may also be involved in the multi-step prostatic oncogenesis besides its putative role in gonadoblastoma and testicular seminoma.

A photo-assisted electro-chemical etching technique has recently been developed by Lehmann for the fabrication of porous silicon and highly anisotropic trenches in silicon. The discovery of room temperature photo-luminescence of porous silicon and its suitability for the fabrication of photonic band structures has stimulated a large interest in the development of silicon as an optical material. We have developed the anodic etching technique for the fabrication of quantum wires and photonic band structures. We discuss the electro-chemical process in detail, and report the successful fabrication of a photonic band structure based on macro-porous silicon. The band structure shows a band gap for the H-polarisation state between 2.78 /spl mu/m and 6.25 /spl mu/m.

The present study sought to test the hypothesis that phenytoin acts on normal human-mandible-derived bone cells to induce osteogenic effects. To test the effects of phenytoin on bone cell proliferation, we measured [ 3H]-thymidine incorporation into cell DNA during the final four hr of a 24-hour incubation with phenytoin. Phenytoin at micromolar concentrations significantly stimulated the [3H]-thymidine incorporation in a dose-dependent, biphasic, manner with a maximal effect at from 10 to 50 uM. We confirmed the proliferative effect of phenytoin by counting cell number. To evaluate the effects of phenytoin on osteoblastic differentiation, we determined alkaline-phosphatase specific activity and found that phenytoin at micromolar concentrations significantly increased that activity in a dose-dependent manner, with maximal stimulation at approximately 1 μM. To investigate the effects of phenytoin on mature osteoblastic activities, we measured de novo collagen synthesis and osteocalcin secretion. Mitogenic doses of phenytoin significantly increased collagen synthesis and osteocalcin secretion in a dose-dependent, biphasic, manner, with the maximal stimulatory dose at from 5 to 10 uM. In summary, phenytoin at micromolar ranges increased (a) [3H]-thymidine incorporation and cell number, (b) alkaline-phosphatase specific activity, (c) collagen synthesis, and (d) osteocalcin secretion in monolayer cultures of normal human-mandible-derived bone cells. These observations are consistent with the premise that low doses of phenytoin act on human craniofacial bone cells to stimulate cell proliferation, differentiation, and mature osteoblastic activities to stimulate bone formation.