Fractures of the proximal fifth metatarsal

Fractures of the proximal portion of the fifth metatarsal may be classified as avulsions of the tuberosity or fractures of the shaft within 1.5 cm of the tuberosity. Tuberosity avulsion fractures cause pain and tenderness at the base of the fifth metatarsal and follow forced inversion during plantar flexion of the foot and ankle. Local bruising, swelling and other injuries may be present. Nondisplaced tuberosity fractures are usually treated conservatively, but orthopedic referral is indicated for fractures that are comminuted or displaced, fractures that involve more than 30 percent of the cubo-metatarsal articulation surface and fractures with delayed union. Management and prognosis of both acute (Jones fracture) and stress fracture of the fifth metatarsal within 1.5 cm of the tuberosity depend on the type of fracture, based on Torg's classification. Type I fractures are generally treated conservatively with a nonweight-bearing short leg cast for six to eight weeks. Type II fractures may also be treated conservatively or may be managed surgically, depending on patient preference and other factors. All displaced fractures and type III fractures should be managed surgically. Although most fractures of the proximal portion of the fifth metatarsal respond well to appropriate management, delayed union, muscle atrophy and chronic pain may be long-term complications.

Acute and subacute effects of naturally occurring estrogens on luteinizing hormone secretion in the ovariectomized rat: Part 2

Acute intravenous administration of the phytoestrogen genistein (G) blocks the gonadotropin-releasing hormone-(GnRH)-induced rise of luteinizing hormone (LH) in ovariectomized rats. The present experiments were performed to determine whether subacute administration of G or the mycoestrogens zearalenone and zearalenol would affect GnRH-induced or progesterone-induced LH secretion in ovariectomized rats. Charles River CD rats were ovariectomized and used 2 to 5 weeks later. Blood samples were obtained either via decapitation or via intraatrial cannulae three days after compounds were injected subcutaneously in sesame oil or corn oil vehicle. LH was measured by RIA. Pretreatment with estradiol benzoate suppressed LH levels at 1200 h, while G had no effect. Challenge with progesterone (8 mg/kg BW, sc) evoked LH release at 1600 h in rats pretreated with estradiol benzoate, but LH levels did not change in rats pretreated with G, zearalenone, or zearalenol. While GnRH-induced LH secretion was preserved in rats pretreated with estradiol, no LH response was detected in rats pretreated with the higher dose of G (8 mg/kg BW) or either dose of zearalenol (0.8 mg/kg BW or 8 mg/kg BW). We conclude that in the ovariectomized rat 1) subacute administration of G, zearalenone, or zearalenol do not inhibit tonic LH secretion, 2) G, zearalenone, and zearalenol do not provide "estrogenic priming" for progesterone-induced LH secretion; however, 3) G and zearalenol do block GnRH-induced LH secretion. The seemingly selective neuroendocrine effects of these naturally-occurring dietary estrogens emphasize that actions of each putative estrogen must be characterized for each "estrogenic" endpoint.