Red deer stags produce an androgen-dependent mane of long hairs only in the breeding season; in the non-breeding season, when circulating androgen levels are low, the neck hair resembles the rest of the coat. This study was designed to determine whether androgen receptors are present in deer follicles throughout the year or only in the mane (neck) follicles when circulating testosterone levels are high in the breeding season. Although androgens regulate much human hair growth the mechanisms are not well understood; they are believed to act on the hair follicle epithelium via the mesenchyme-derived dermal papilla. The location of androgen receptors in the follicle was investigated by immunohistochemistry and androgen binding was measured biochemically in cultured dermal papilla cells derived from mane and flank follicles during the breeding season and from neck follicles during the non-breeding season.Immunohistochemistry of frozen skin sections using a polyclonal antibody to the androgen receptor localised nuclear staining only in the dermal papilla cells of mane follicles. Saturation analysis assays of 14 primary dermal papilla cell lines using [ The unusual biological model offered by red deer of androgen-dependent hair being produced on the neck in the breeding, but not the non-breeding season, has allowed confirmation that androgen receptors are required in follicle dermal papilla cells for an androgen response; this concurs with previous human studies. In addition, the absence of receptors in the non-breeding season follicles demonstrates that receptors are not expressed unless the follicle is responding to androgens. Androgen receptors may be induced in mane follicles by seasonal changes in circulating hormone(s).

There is a high association of venous outflow stenoses and AVFA. Comprehensive therapy should encompass treatment of any venous outflow stenoses before open AVFA repair. A two-stage repair may decrease tunneled hemodialysis catheter use in patients with multiple aneurysms.

IntroductionNot all newly created arteriovenous fistulas (AVFs) successfully mature and develop into a functioning access for hemodialysis. Percutaneous transluminal angioplasty (PTA) and balloon-assisted maturation (BAM) have been utilized to either treat flow-limiting stenoses or to promote and accelerate maturation. We hypothesized that unusable upper arm AVFs can be rescued by conversion to a functional access using the percutaneous placement of a stent graft (SG).MethodsClinical data on 12 patients with an early non-usable upper arm AVF underwent percutaneous revision using SGs. There were six brachial–cephalic, three brachial–basilic, and three brachial–brachial vein transposition AVFs.ResultsAll patients had either at least two or more stenoses (>2 cm) within the fistula conduit, or a long segment stenosis (>4 cm) in combination with shorter segment stenoses. Nine patients had failed PTA. Three patients had failed BAM at outside access centers. All patients were referred for failure to achieve access cannulation and concomitant hemodialysis through the AVF. SGs were placed retrograde toward the arterial anastomoses and ranged in diameter (6, 7, and 8 mm in four, seven, and one patients, respectively). The average length of the SG was 10 cm (range 5–15 cm). All SGs were post-balloon dilated at the time of placement. All AVFs were salvaged, and patients were able to maintain functional use of their access with cannulation occurring through the SG. The primary patency rate at 6 and 12 months was 91% [95% confidence interval (CI), 56–98%] and 65% (95% CI, 32–87%), respectively (n = 11 and 5 at risk, respectively). The secondary patency rate at 6 and 12 months was 100 and 72% (95% CI, 46–93%), respectively (n = 11 and 7 at risk, respectively).ConclusionThis report outlines a successful initial experience using SGs to rescue, preserve, and convert an unusable upper arm AVF into a functioning hemodialysis access.