Pearly penile papules regress in older patients and with circumcision.

This study assesses the prevalence and correlates of pearly penile papules (PPP) in two non-genitourinary (GU) medicine male cohorts (<25 and >50 years). PPP were categorised in 188 university students (<25 years), based on self-examination, and 70 patients (>50 years), based on clinician examination. PPP were categorised from 1 to 4, based on increasing papule size and distribution. An anonymous questionnaire was used to identify associations with PPP prevalence. The prevalence of PPP was 38.3% in <25 years, and 11.4% in >50 years (P < 0.001). The prevalence of categories 3 and 4 PPP was 8.5% in <25 years, and 1.4% in >50 years (P < 0.05). In the younger age group, the prevalence of PPP was 26.5% in circumcised participants, and 42.4% in uncircumcised participants (P < 0.05), but was unrelated to either frequency of sexual intercourse or time since first sexual intercourse. In conclusion, PPP disappear with age, and any PPP in patients >50 years are less marked than those in patients <25 years. Patients should be advised accordingly. PPP are less prevalent in circumcised men. Patients could be advised to wear the foreskin rolled back - this may maximize exposure of the coronal area to normal abrasion, which may hasten PPP regression.

Genetic studies of mutants in a high-affinity methionine transport system in Salmonella typhimurium.

A total of 30 metP mutations defective in the high-affinity methionine transport system were linked in P1 transduction to the zaf-1351::Tn10 insertion mutation at min 5-6 on the Salmonella typhimurium chromosome map. The relationship of metP to several other markers in this region was studied. Methionine transport was strongly inhibited by arsenate, suggesting that the metP system belongs to the shock-sensitive category and possesses a periplasmic binding protein. However, other experiments provided less clear cut evidence. Transport activity was only slightly reduced by osmotic shock; a methionine binding activity was detected in shock fluids from the wild-type strain, and although this activity was reduced by 50% in 3 frameshift mutants, mutants without any activity were not found. No differences were detected in the shock fluids of the 30 mutants when examined by SDS-polyacrylamide gel electrophoresis.