Burrow architecture of the ghost crab Ocypode ceratophthalma on a sandy shore in Hong Kong

The ghost crab Ocypode ceratophthalma (Pallas) creates burrows of variety shapes at different ages. Juveniles (mean carapace length 11 mm) produced shallow J-shaped burrows, which incline vertically into the substratum (mean depth 160 mm). Larger crabs (17-25 mm carapace length) have Y-shaped and spiral burrows (mean depth 361 mm). These Y-shaped burrows have a primary arm, which extends to the surface forming the opening, and a secondary arm which terminates in a blind spherical ending. The two arms join in a single shaft and end with a chamber at the base. The secondary arms and chambers are believed to be used for mating or as a refuge from predation. The spiral burrows have spiral single channel ending in a chamber. Older crabs (mean carapace length 32.6 mm) had simple, straight single tube burrows, which inclined into the substratum at mean of 73° and had a mean depth of 320 mm. During summer daytime periods, the burrows shelter the crabs from heat and desiccation stress. The sand surface temperature at the burrow opening was ∼48°C but temperatures inside the burrows can drop to 32°C at a depth of 250 mm. Variation in the burrow architecture with crab age appears to be related to the crab's behaviour. Juvenile crabs have smaller gill areas and move out of the burrows regularly to renew their respiratory water and, as a result, they do not need a deep burrow. Larger crabs, in contrast, can tolerate prolonged periods without renewing their respiratory water and therefore create deeper and more complex burrows for mating and refuges. © Springer 2006

Treatment of Enterococcal Peritonitis in Peritoneal Dialysis Patients by Oral Amoxicillin or Intra-Peritoneal Vancomcyin: a Retrospective Study

Background/Aims: Enterococcal peritonitis in peritoneal dialysis (PD) patients is associated with a high complication rate. The optimal treatment regimen of PD-related enterococcal peritonitis is controversial. The latest international guideline recommends intra-peritoneal (IP) vancomycin. Although ampicillin is often effective for systemic enterococcal infections, they have little in vitro activity when added to common PD solutions. Since oral amoxicillin achieves therapeutic drug level in the peritoneal cavity, we explore the efficacy of oral amoxicillin for enterococcal peritonitis. Methods: We studied 105 episodes of enterococcal peritonitis over 20 years in our unit; 43 (41.0%) were treated with oral amoxicillin, and 62 (59.0%) with IP vancomycin. Their clinical outcome was reviewed. Result: The overall primary response rate to oral amoxicillin and IP vancomycin was 76.4% and 85.5%, respectively (p = 0.3). The complete cure rate of oral amoxicillin and IP vancomycin was 55.8% and 54.8%, respectively (p = 0.8). When the 5 episodes of ampicillin-resistant Enterococcus episodes were excluded, the primary response rate and complete cure rate of oral amoxicillin were 86.8% and 63.2%, respectively. Conclusion: Oral amoxicillin has an excellent primary response rate and complete cure rate for PD-related peritonitis episodes caused by Enterococcus species, indicating that oral amoxicillin is a valid and convenient therapeutic option for enterococcal peritonitis episodes

Frailty in Chinese Peritoneal Dialysis Patients: Prevalence and Prognostic Significance

Background/Aims: Previous studies showed that frailty is prevalent in both pre-dialysis and dialysis patients. However, the prevalence and prognostic implication of frailty in Chinese peritoneal dialysis (PD) patients remain unknown. Methods: We used a validated questionnaire to determine the Frailty Score of 193 unselected prevalent PD patients. All patients were then followed for 2 years for their need of hospitalization and mortality. Results: Amongst the 193 patients, 134 (69.4%) met the criteria of being frail. Frailty Score significantly correlated with Charlson's comorbidity score (r = 0.40, p Conclusions: Frailty is prevalent among Chinese PD patients. Frail PD patients have a high risk of requiring hospitalization and their hospital stay tends to be prolonged. Early identification may allow timely intervention to prevent adverse health outcomes in this group of patients

Plasma Mitochondrial DNA Level is a Prognostic Marker in Peritoneal Dialysis Patients

Background/Aims: Circulating bacterial DNA fragment is related to systemic inflammatory state in peritoneal dialysis (PD) patients. We hypothesize that circulating mitochondrial DNA, which has a similar structure with bacterial DNA, correlates with systemic inflammatory state and predicts cardiovascular event in new PD patients. Methods: We measured plasma mitochondrial DNA level by quantitative polymerase chain reaction (PCR) in 197 new PD patients and 150 patients with chronic kidney disease. PD patients were followed for 24 months for the development of cardiovascular event, hospitalization, and patient survival. Results: There was a stepwise increase in plasma mitochondrial DNA level with worsening renal function. The average plasma mitochondrial DNA level was 18.0 ± 1.2 PCR cycles. Plasma mitochondrial DNA level correlated with serum CRP level (r = -0.538, p Conclusion: Plasma mitochondrial DNA level significantly correlates with systemic inflammatory state, and is a strong predictor of cardiovascular event as well as the need of hospitalization in new PD patients