Sildenafil: a urologist's view

Erectile dysfunction (ED) is a common problem with a multifactorial aetiology. The treatment of ED has been revolutionised by the introduction of intracavernosal injections some two decades ago. However, the recent development of the orally-administered drug sildenafil (Viagra) has had a major impact on the treatment of ED. We discuss the trials with sildenafil with special reference to cardiovascular risk factors associated with ED.     

The treatment of hypertension in patients with erectile dysfunction

Hypertension is another predictor of erectile dysfunction (ED). This is further evidence supporting a link between the pathogenesis of atherosclerotic disease and ED. In one study (TOMHS) involving hypertensive patients, the incidence of ED was 14.4%. The drugs used to treat hypertension may cause ED. However, there is little trial-based evidence to indicate which drugs are more likely to cause this side effect. In general, thiazide diuretics and beta-blockers seem to cause ED more often. In contrast, the alpha-blocker, doxazosin, has not been associated with an increased incidence of ED as a side effect. Doxazosin also improves urinary flow in patients with benign prostatic hyperplasia (BPH). This condition is common in elderly men as is hypertension and ED. Therefore, doxazosin may present a special advantage among this group of patients. This alpha-blocker would also be a good choice in patients with impaired glucose tolerance/diabetes because it improves insulin sensitivity. Moreover, ED and hypertension are more prevalent among diabetics. On a more speculative note, doxazosin may potentiate the therapeutic impact of specific treatments for ED.     

显微注射后家兔转基因受精卵的体外培养和移植成活率的观察研究

目的：研究家兔受精卵经显微注射转基因过程的耐受性，建立转基因动物技术平台。方法：(1)家兔超数排卵诱导；(2)对2000个家兔受精卵进行显微注射技术操作；(3)对1280个受精卵进行显微注射后体外培养观察；(4)216个注射后受精卵向13只受体母兔输卵管进行移植．结果：(1)经显微注射后受精卵进行体外培养有68％的受精卵能够发育至桑椹胚和囊胚；(2)目前有7只受体母兔经输卵管转基因受精卵移植分别产下3，4，5，2，6，13，7只仔兔。结论：(1)受精卵能够在体外经受显微注射转基因过程的损伤，但暴露于体外的操作时间应尽可能的缩短；(2)显微注射操作技术的熟练程度是实验成功的关键。     

Revisiting the pestilence of Helicobacter pylori: insights into geographical genomics and pathogen evolution.

Helicobacter pylori causes chronic gastritis and plays important roles in peptic ulcer disease, gastric carcinoma, and mucosa-associated lymphoid tissue (MALT) lymphoma. It is believed that H. pylori infects over 50% of the worlds' population. However, only a small subset of infected people experience H. pylori-associated illnesses. Associations with disease-specific factors remain enigmatic. The contribution of comparative genomics to our understanding of the genome organisation and diversity of H. pylori is exemplified herein. The discovery of the cag pathogenicity island has revolutionised our understanding of the molecular pathogenesis of gastroduodenal ulcers. Another type IV secretion system, the comB gene cluster, provides a novel transformation system. Identification of this cluster has boosted our perception of horizontal gene transfer and gene mosaicism in H. pylori as a result of natural competence. Recent discovery of a third type IV secretion system called tfs3 encoding cluster in the so called plasticity zone of the H. pylori has gained significant attention, although its role is not clear. Study of the evolution of polymorphisms and sequence variation in H. pylori populations on a global basis is contributing to understanding of the history of human population migration and co-evolution of this pathogen with its human host. Possible symbiotic relationships were debated since the discovery of this pathogen. The debate has been further intensified as recent studies have posed the intriguing possibility that H. pylori infection may be advantageous in some humans. This analogy is based on increased incidence of diseases like gastro-oesophageal reflux disease (GERD), Barrett's oesophagus and adenocarcinoma of the oesophagus following H. pylori eradication in some patients.     

An unusual orbito-cranial foreign body.

The rarity of orbito-cranial gun shot injury in both war and civilian practice has been reported. In a large series of 351 missile head injuries in the Vietnam war, orbital penetration was noted in 0.6% cases only. Review of literature shows that orbital injury was ipsilateral to the cerebral injury in most reported cases. We have previously reported a rare case of left parieto-occipital lobe injury due to gun shot wound of the contralateral (right) orbit. The case reported here sustained a bullet injury to the left frontal bone but the missile was located below the contralateral (right) optic canal. The rarity of the case prompted this report.     

Arthroscopic resection of chondroblastoma of the knee.

We present a case of chondroblastoma of the upper tibia treated by complete arthroscopic excision. The diagnostic difficulties raised by the case are discussed. This method of treatment has not, to our knowledge, been reported in the literature.