Plasma testosterone levels during the testicular cycle of the redwinged blackbird (Agelaius phoeniceus)

Fluctuations in plasma testosterone concentration during the testicular cycle of adult captive redwinged blackbirds were measured by radioimmunoassay. A peak in testosterone (range: 24.8-27.4 ng/10 ml) was associated with small testes that weighed less than 100 mg in the photosensitive stage. In the regressive stage, testosterone concentration was uniformly low (mean +/- SEM: 6.6 +/- 0.6 ng/10 ml) over a range of gonadal weights (range: 6.5-799.8 mg). Surprisingly, testosterone was detected in birds in the refractory stage maintained on a long photoperiod for 35 days (7.7 +/- 0.6 ng/10 ml) and in two birds kept for about 27 weeks (10.3 and 12.3 ng/10 ml). The relationship between plasma testosterone levels and the extent of testosterone synthesis by blackbird testes is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22385/1/0000834.pd

Sex-steroid formation in gonadal tissue homogenates during the testicular cycle of the redwinged blackbird (agelaius phoeniceus)

Fluctuations in the in vitro metabolism of pregnenolone-3H and progesterone-14C were studied in the testes of captive, photoinduced, adult Redwinged Blackbirds (Agelaius phoeniceus) during the gonadal cycle. Starting material utilization was high (87-99%) during the photosensitive stage (breeding period), decreased during the regressive stage, and leveled off at about 40% in the refractory stage. The extent of testosterone synthesis varied in a bimodal pattern during the testicular cycle. Peaks in testosterone synthesis occurred during the photosensitive and regressive stages. However, testosterone formation was not detected in the refractory stage.In addition to testosterone, 20[beta]-dihydropregnenolone (3[beta],20[beta]-dihydroxypregn-5-ene), 20[alpha]-dihydropregnenolone (3[beta],20[alpha]-dihydroxypregn-i-ene), 20[beta]-dihydroproges-terone (20[beta]-hydroxypregn-4-en-3-one), and 20[alpha]-dihydroprogesterone (20[alpha]-hydroxy-pregn-4-en-3-one) were isolated. The. 20[alpha]-pregnenols were detected only during the regressive and refractory stages. Moreover, an inverse relationship was seen between the formation of 20[alpha]-pregnenols and testosterone in the photosensitive and refractory stages.The physiological significance of a bimodal pattern of testosterone synthesis and of a restricted occurrence of 20[alpha]-pregnenol formation in blackbirds is discussed in reference to the proposal by Lacy that two major populations of steroidogenic cells are present in the testis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22216/1/0000649.pd

Abdominal aortic aneurysm repair with the Zenith stent graft: Short to midterm results

AbstractPurpose: The purpose of this study was to assess the short-term and mid-term results of endovascular aneurysm repair with the Zenith stent graft in a single-center prospective study. Method: Between October 1998 and July 2001, we used the Zenith stent graft for elective endovascular aneurysm repair in 116 patients, six of whom were women. The mean age was 75 years, and the mean aneurysm diameter was 60.3 ± 8.8 mm. Stent grafts were oversized 10% to 20% relative to computed tomographic (CT) scan-based diameter measurements. All repairs were performed in the operating room through surgically exposed femoral arteries. The results were assessed before discharge with three-phase, contrast-enhanced CT scan and plain abdominal radiograph. These studies were repeated at 1, 6, 12, and 24 months after operation. Follow-up periods ranged from 1 to 34 months. Results: No failed insertions and no conversions to open surgery occurred. The diameter of the main body of the stent graft was 28 mm or more in 73 patients (63%). Additional stents were inserted during surgery to treat kinking in eight patients (6.9%) and renal artery encroachment in two patients (1.7%). Mean fluoroscopy time was 35.1 ± 18.3 minutes, contrast load was 146 ± 53 mL (350 mg/mL), and estimated blood loss was 249 ± 407 mL. The major complication rate was 9.5%, and the minor complication rate was 10.3%. The perioperative complications were myocardial infarction in four patients, arrythmia in four patients, and pulmonary embolism, renal failure, stroke, small bowel obstruction, femoral stenosis, digital embolism, and graft limb thrombosis in one patient each. All 116 patients went home from the hospital, but one patient died 2 weeks later of a combination of pulmonary embolism and myocardial infarction. Endoleak was seen on the first CT scan in 16 patients (15%); 15 were type II, and one was type III. No endoleaks of type I or IV were seen. Additional interventions were performed for each of the following conditions: type II endoleak (n = 4), type III endoleak (n = 1), femoral clamp injury (n = 1), renal artery stenosis (n = 1), and graft limb occlusion (n = 1). One patient had acute aneurysm dilatation and rupture caused by a type II endoleak through the inferior mesenteric artery 6 months after stent graft implantation. No cases were seen of late graft occlusion, stent graft migration, stent fracture, barb fracture, or secondary endoleak. Conclusion: The Zenith device is safe, versatile, and effective in the short to medium term. Most patients need wide stent grafts (≥28 mm proximally and ≥16 mm distally) to achieve 10% to 20% oversizing to prevent type I endoleak. (J Vasc Surg 2002;36:217-25.

Endoleak after endovascular repair of abdominal aortic aneurysm

AbstractPurpose: We sought to assess the role of endovascular techniques in the management of perigraft flow (endoleak) after endovascular repair of an abdominal aortic aneurysm. Method: We performed endovascular repair of abdominal aortic aneurysm in 114 patients, using a variety of Gianturco Z-stent–based prostheses. Results were evaluated with contrast-enhanced computed tomography (CT) at 3 days, 3 months, 6 months, 12 months, and every year after the operation. An endoleak that occurred 3 days after operation led to repeat CT scanning at 2 weeks, followed by angiography and attempted endovascular treatment. Results: Endoleak was seen on the first postoperative CT scan in 21 (18%) patients and was still present at 2 weeks in 14 (12%). On the basis of angiographic localization of the inflow, the endoleak was pure type I in 3 cases, pure type II in 9, and mixed-pattern in 2. Of the 5 type I endoleaks, 3 were proximal and 2 were distal. All five resolved after endovascular implantation of additional stent-grafts, stents, and embolization coils. Although inferior mesenteric artery embolization was successful in 6 of 7 cases and lumbar embolization was successful in 4 of 7, only 1 of 11 primary type II endoleaks was shown to be resolved on CT scanning. There were no type III or type IV endoleaks (through the stent-graft). Endoleak was associated with aneurysm dilation two cases. In both cases, the aneurysm diameter stabilized after coil embolization of the inferior mesenteric artery. There were two secondary (delayed) endoleaks; one type I and one type II. The secondary type I endoleak and the associated aneurysm rupture were treated by use of an additional stent-graft. The secondary type II endoleak was not treated. Conclusions: Type I endoleaks represent a persistent risk of aneurysm rupture and should be treated promptly by endovascular means. Type II leaks are less dangerous and more difficult to treat, but coil embolization of feeding arteries may be warranted when leakage is associated with aneurysm enlargement. (J Vasc Surg 2001;34:98-105.

90Y Radioembolization for Hepatic Malignancy in Patients with Previous Biliary Intervention: Multicenter Analysis of Hepatobiliary Infections

PurposeTo determine the frequency of hepatobiliary infections after transarterial radioembolization (TARE) with yttrium 90 (90Y) in patients with liver malignancy and a history of biliary intervention.Materials and MethodsFor this retrospective study, records of all consecutive patients with liver malignancy and history of biliary intervention treated with TARE at 14 centers between 2005 and 2015 were reviewed. Data regarding liver function, 90Y dosimetry, antibiotic prophylaxis, and bowel preparation prophylaxis were collected. Primary outcome was development of hepatobiliary infection.ResultsOne hundred twenty-six patients (84 men, 42 women; mean age, 68.8 years) with primary (n = 39) or metastatic (n = 87) liver malignancy and history of biliary intervention underwent 180 procedures with glass (92 procedures) or resin (88 procedures) microspheres. Hepatobiliary infections (liver abscesses in nine patients, cholangitis in five patients) developed in 10 of the 126 patients (7.9%) after 11 of the 180 procedures (6.1%; nine of those procedures were performed with glass microspheres). All patients required hospitalization (median stay, 12 days; range, 2–113 days). Ten patients required percutaneous abscess drainage, three patients underwent endoscopic stent placement and stone removal, and one patient needed insertion of percutaneous biliary drains. Infections resolved in five patients, four patients died (two from infection and two from cancer progression while infection was being treated), and one patient continued to receive suppressive antibiotics. Use of glass microspheres (P = .02), previous liver resection or ablation (P = .02), and younger age (P = .003) were independently predictive of higher infection risk.ConclusionInfectious complications such as liver abscess and cholangitis are uncommon but serious complications of transarterial radioembolization with 90Y in patients with liver malignancy and a history of biliary intervention.© RSNA, 2018Online supplemental material is available for this article