Casilda G. Black

A subclassification of SSc patients is proposed by a group of experienced investigators. The subsets are defined by skin involvement with limited cutaneous SSc (lcSSc) patients having no taut skin proximal to the knees, elbows or clavicles and diffuse cutaneous SSc (dcSSc) patients having truncal skin tautness.

OBJECTIVE: Endothelin-1 (ET-1) has been implicated in the pathogenesis of systemic sclerosis (SSc) as it is both a potent vasoconstrictor and fibroblast mitogen and is raised in the circulation of patients with SSc and primary Raynaud's phenomenon. METHODS: We examined the localization and level of expression of ET-1 and its putative receptors in clinically "uninvolved" (i.e., prescleroderma skin) and involved skin from patients with diffuse cutaneous systemic sclerosis (dcSSc), using the alkaline phosphatase antialkaline phosphatase technique while ET-1 binding sites were examined using in vitro autoradiography. RESULTS: There was an increase in dermal ET-1 staining in clinically uninvolved and involved skin from patients with early active dcSSc compared with late stage fibrotic SSc skin and normal skin from healthy volunteers. Increased ET-1 staining was associated predominantly with the superficial vessels in the SSc skin sections. In addition, there was a significant increase in [125I]ET-1 binding to superficial vessels and the dermal/epidermal junction in SSc skin compared with the binding to similar structures in normal tissue. There was no change in [125I]ET-1 binding to the deep dermal vessels in both SSc and normal skin. This increase in [125I]ET-1 binding in SSc skin was not maintained with increasing tissue fibrosis. CONCLUSION: The presence of increased ET-1 levels as well as its binding sites in both the prescleroderma and involved skin of patients with dcSSc compared to controls suggests that ET-1 may play a role in the pathology of dermal fibrosis and vasoconstriction in SSc.

OBJECTIVE: To develop a simple assessment of functional ability in patients with scleroderma and to examine its reliability both as a patient self-administered instrument and when administered by a trained observer. METHODS: An 11 item, 4 grade, functional assessment questionnaire was developed after extensive consultation with patients, physiotherapists (PT), and occupational therapists (OT) with the aim of including all functional areas of relevance. The instrument was self-administered by patients after an interval of 7 days. In the interval, the patients were assessed using the same instrument by direct observation from both a PT and an OT. Forty-seven patients with scleroderma, of varying severity, were recruited from 2 centers. Results were similar for both centers and data were pooled for analysis. RESULTS: Agreement between the patients' first and 2nd assessment was good for all questions (estimated kappas 0.69 to 0.94) with no evidence of an order effect. Agreement was also good between therapists (estimated kappas 0.47 to 0.81). There was poor agreement between patients and therapists, with patients rating their disability substantially higher compared to the standardized therapist assessment. CONCLUSION: This assessment schedule has high face and content validity and has excellent reliability both between trained therapists and within patients over a short time period. Its administration either as a self-report or by a therapist depends, in part, on the type of investigation undertaken.

The rhoptry of the malaria parasite Plasmodium falciparum is an unusual secretory organelle that is thought to be related to secretory lysosomes in higher eukaryotes. Rhoptries contain an extensive collection of proteins that participate in host cell invasion and in the formation of the parasitophorous vacuole, but little is known about sorting signals required for rhoptry protein targeting. Using green fluorescent protein chimeras and in vitro pull-down assays, we performed an analysis of the signals required for trafficking of the rhoptry protein RAP1. We provide evidence that RAP1 is escorted to the rhoptry via an interaction with the glycosylphosphatidyl inositol-anchored rhoptry protein RAMA. Once within the rhoptry, RAP1 contains distinct signals for localisation within a sub-compartment of the organelle and subsequent transfer to the parasitophorous vacuole after invasion. This is the first detailed description of rhoptry trafficking signals in Plasmodium.