We have characterized platelet-derived growth factor (PDGF) C, a novel growth factor belonging to the PDGF family. PDGF-C is a multidomain protein with the Nterminal region homologous to the extracellular CUB domain of neuropilin-1, and the C-terminal region consists of a growth factor domain (GFD) with homology to vascular endothelial growth factor (25%) and PDGF Achain (23%). A serum-sensitive cleavage site between the two domains allows release of the GFD from the CUB domain. Competition binding and immunoprecipitation studies on cells bearing both PDGF ␣ and ␤ receptors reveal a high affinity binding of recombinant GFD (PDGF-CC) to PDGF receptor-␣ homodimers and PDGF receptor-␣/␤ heterodimers. PDGF-CC exhibits greater mitogenic potency than PDGF-AA and comparable or greater mitogenic activity than PDGF-AB and PDGF-BB on several mesenchymal cell types. Analysis of PDGF-CC in vivo in a diabetic mouse model of delayed wound healing showed that PDGF-CC significantly enhanced repair of a full-thickness skin excision. Together, these studies describe a third member of the PDGF family (PDGF-C) as a potent mitogen for cells of mesenchymal origin in in vitro and in vivo systems with a binding pattern similar to PDGF-AB.

Few studies have investigated peripheral muscle strength and quality in patients with cystic fibrosis (CF). The present study tested the isometric and isokinetic strength of the quadriceps and hamstrings using an isokinetic dynamometer and a strength-testing chair in 25 CF adults and 25 controls. Total body and leg muscle mass were determined by dual-energy X-ray absorptiometry, and bone mineral density (BMD) was also measured. Both muscle strength and muscle mass (total body and leg) were decreased in the CF group. In both groups there was a highly significant relationship between quadriceps strength and leg muscle mass (CF, r=0.7, P=0.0002; controls, r=0.6, P=0.0013). When strength was normalized for muscle size, there was no significant difference between the two groups. Total body and leg BMD were significantly reduced in CF subjects compared with controls. However, when corrected for height, the differences disappeared. There was a significant relationship found between leg muscle mass and leg BMD. We conclude that CF adults are significantly weaker than controls. This is due to lower muscle mass, and not to a reduced force-generating capacity of the muscle, implying that there is no decrease in the quality of CF muscle. BMD is also reduced in CF subjects, and this appears to be related to shorter stature in this group.

Risk of type 1 diabetes at 3 years is high for initially multiple and single Ab+ IT and multiple Ab+ NT. Genetic predisposition, age, and male sex are significant risk factors for development of Ab+ in twins.

Eight clinicians in a renal dialysis unit were asked to classify the suitability of 100 cases (some real, some simulated) for regular haemodialysis. Seven categories were used, ranging from "excellent prospect: accept without reservation" to "unequivocal rejection," based on 18 items of information previously agreed on as sufficient for the purpose. The ways in which they classified the cases differed considerably; only six cases were placed in the same category by all eight clinicians, and this was the "unequivocal rejection" category. Analysis of the extent to which they made effective use of the items showed that between three and nine items were used to a sufficient extent to reach significance for the 100 cases.

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