Inhibition of matrix metalloproteinase-9 activity improves coronary outcome in an animal model of Kawasaki disease

Kawasaki disease (KD) is the leading cause of acquired heart disease of children in North America. It is characterized by a massive immune activation and multi-system vasculitis, which evolves into a site-specific inflammatory response focused at the coronary arteries. Coronary artery (CA) inflammation leads to elastin breakdown, destruction of the vessel wall and aneurysm formation. We have demonstrated recently the pivotal role of tumour necrosis factor (TNF)-alpha-mediated matrix metalloproteinase (MMP)-9 activity in the pathogenesis of elastin breakdown in a murine model of KD, Lactobacillus casei cell wall extract-induced coronary arteritis. Using this model, we evaluated the in vitro effects of doxycycline, an antibiotic with MMP inhibitory function, in modulating key pathogenic stages of disease leading to CA damage. Doxycycline inhibits T cell activation and TNF-alpha production in peripheral immune cells, as assessed by thymidine incorporation and a TNF bioassay respectively. Additionally, doxycycline inhibits directly MMP-9 enzymatic activity derived from TNF-alpha-stimulated vascular smooth muscle cells as assayed by zymography. More importantly, in vivo treatment of Lactobacillus casei cell wall extract (LCWE)-injected mice with doxycycline reduces significantly the incidence of CA elastin breakdown and reduces loss of elastin. Therefore, doxycycline can mitigate TNF-alpha-induced MMP-9-mediated coronary elastin breakdown and improve coronary outcome. Agents with the ability to inhibit both inflammation and the downstream effects of inflammation, such as MMP-9 activity, offer a promising therapeutic strategy for the management of children with KD.

Hospital re-admission in patients with acute exacerbation of chronic obstructive pulmonary disease

A retrospective study was carried out in a Hong Kong regional hospital with 24-h emergency service, to study the factors associated with shorter time to re-admission after acute exacerbation of chronic obstructive pulmonary disease (COPD). From 1 January 1997 to 31 December 1997, the first admission (index admission) of each patient through the emergency room with COPD/chronic bronchitis/emphysema was included. A total of 551 patients fulfilled the inclusion criteria. The total acute and rehabilitative length of stay (mean +/- SD) was 9.41+/-11.67 days. Within 1 year after discharge, 327 patients (59 35%) were re-admitted at least once. Median time to first re-admission after discharge was 240 days. By Cox regression analysis, the following factors were independently associated with shorter time to re-admission: hospital admission within 1 year before index admission, total length of stay in index admission > 5 days, nursing home residency, dependency in self-care activities, right heart strain pattern on electrocardiogram, on high dose inhaled corticosteroid and actual bicarbonate level > 25 mmol l(-1). These factors may be relevant in the future planning of healthcare utilization for COPD patients.

Arthroscopic treatment of pigmented villonodular synovitis of the knee

Pigmented villonodular synovitis (PVNS) is a rare disease, with multiple forms, anatomic sites, and treatment methods having been described. During a 10-year period, 14 patients, 7 male and 7 female, average age 35 years (range, 19 to 64 years) were treated for PVNS with arthroscopic partial or total synovectomy. Average follow-up was 42 months (range, 8 to 83 months). Twelve patients had diffuse and 2 had a localized form. Results were assessed subjectively, clinically, and radiographically, and were rated as excellent, good, fair, or poor. There were no complications and 10 patients (72%) were rated as excellent or good, 2 patients (14%) as fair, and 2 patients (14%) as poor. The recurrence rate was 14% and occurred in the group with diffuse PVNS. Radiographs did not show any bone erosion. The most widely accepted treatment for PVNS is synovectomy, and both open and arthroscopic synovectomy have been advocated as treatment. Advantages of arthroscopic treatment include accurate evaluation of the knee joint, treatment of other pathology, more rapid rehabilitation, decreased risk of joint stiffness, and less pain. In our experience, it appears that arthroscopic synovectomy is an effective method of treatment of this disorder.