Saccular Aneurysm of the Azygos Anterior Cerebral Artery: Three Case Reports

The azygos anterior cerebral artery, a rare anomaly in the circle of Willis in which only a single vessel supplies the medial aspects of both anterior cerebral hemispheres, is closely associated with saccular aneurysms. We present three cases of azygos anterior cerebral artery aneurysms among the 781 cerebral aneurysms surgically treated at our institution in an 11-year period. These three cases all involved elderly women who presented with subarachnoid hemorrhage. Conventional cerebral angiography and CT angiography revealed small saccular aneurysms at the distal ends of the azygos anterior cerebral arteries. These aneurysms were clipped successfully using a bifrontal interhemispheric approach. Hence, the pathogenesis of these particular aneurysms relating to hemodynamic change, associated anomalies, and surgical pitfalls is discussed with review of literature.     

AC/A ratios in myopic and emmetropic Hong Kong children and the effect of timolol§

Purpose: Caucasian children with myopia have elevated response accommodative vergence to accommodation (AC/A) ratios. The purpose of this study was twofold: to determine if response AC/A ratios vary with refractive error and with myopic progression rate in Hong Kong Chinese children, and to determine the effect of beta‐adrenergic antagonism with topical timolol application on AC/A ratios. Methods: Thirty children aged eight to 12 years participated in the study. All refractive errors were corrected with spectacle lenses. Accommodative responses were measured using a Shin‐Nippon autorefractor and concurrent changes in vergence were assessed using a vertical prism and a Howell‐Dwyer card at three metres and 0.33 metre. Accommodative demand was altered using plus or minus two dioptre lenses and lens‐ and distance‐induced response AC/A ratios were calculated. Measurements were repeated 30 minutes after the instillation of topical timolol maleate (0.5 per cent). Results: AC/A ratios appeared higher in progressing myopic children but the difference was not statistically significant. Timolol application reduced accommodative convergence (AC) in the stable myopes (reduction = ‐3 ± 1.14^A) but not in the emmetropes (0.69 ± 0.9^P) or progressing myopes (0.16 ± 0.43^A) and this difference between refractive groups was statistically s ignificant (F^2,27= 3.766; P= 0.036). However, timolol did not produce a significant change in the accommodative response to positive or negative lenses or response AC/A ratios. Conclusions: We did not find that AC/A ratios in myopic Chinese children were elevated and therefore, it is unlikely that elevated AC/A ratios are responsible for the high levels of myopia that occur in Hong Kong. The finding that timolol reduced AC in the stable myopes suggests that the autonomic control of accommodative convergence in these children may be different from that in emmetropic children and those with progressing myopia.     

Factors affecting penetration of zona-free hamster ova

The sperm penetration assay is an expensive, time-consuming test to assess male fertility in vitro. Although some investigators are enthusiastic in its application, others feel that it is not sensitive or specific enough to be used as part of the routine infertility evaluation. Indeed, this bioassay is not a faithful reproduction of in vivo conditions. However, if the SPA is abnormal, it is unlikely that sperm will fertilize a human ovum in vivo. Conversely, a normal SPA does not guarantee successful in vivo fertilization. No bioassay can be absolute in its predictive value, but false-negative results must be kept to a minimum for this bioassay to be of any clinical significance. Each laboratory performing the SPA should optimize the assay for sensitivity, reproducibility, and minimization of false-negative results and then establish normal and abnormal ranges of its own. If the limitations of the SPA are kept in mind, and if we employ it very selectively, it may still be useful.     

Study on the mechanism of an experimental immunological intrahepatic cholestasis model.

Tuberculin-sensitized guinea pigs were intravenously injected with heat-killed Propionibacterium acnes followed by an intravenous injection of purified protein derivatives 7 day later, resulting in the induction of intrahepatic cholestasis. Using this experimental model, the following results were obtained: (1) Both uptake and release of bile acid were inhibited in the hepatocytes prepared from the cholestasis guinea pigs. (2) The results of the erythritol clearance method indicated that the decrease in bile flow observed in the cholestasis guinea pigs was mostly attributable to the reduced bile excretion from the canaliculi. (3) The decrease in the formation of bile acid independent bile flow was the cause of the decrease in bile flow observed in the cholestasis guinea pigs. (4) There was no change in the permeability of the interhepatocellular tight junction in the cholestasis guinea pigs.     

Ultrasonographic measurement of shoulder subluxation in patients with post-stroke hemiplegia.

OBJECTIVE: To evaluate the ultrasonographic measurement of shoulder subluxation in patients with post-stroke hemiplegia. DESIGN: Prospective, single blind study. PATIENTS: A total of 41 patients with post-stroke hemiplegia were included (24 men and 17 women, mean age 56 years (standard deviation 11), age range 34-78 years). METHODS: Clinical evaluation of the affected shoulder was assessed using the Motricity Index scores and the Modified Ashworth Scale. Two ultrasonographic measurements were taken to check intra-rater reliability. The shoulder subluxation ratio was determined as the ratio of the radiographic vertical and horizontal distance, and the ultrasonographic lateral and anterior distances in the affected shoulder divided by that in the unaffected shoulder. RESULTS: Intraclass correlation coefficients of the repeated ultrasonographic lateral/anterior distance measurements in the unaffected and affected shoulders were 0.979/0.969 and 0.950/0.947, respectively. Ultrasonographic lateral/anterior distance ratios were negatively correlated with Motricity Index scores of the affected shoulder abduction (r = -0.490, p < 0.001/ r = -0.671, p < 0.001). Ultrasonographic anterior distance ratio was negatively correlated with Modified Ashworth Scale score of the affected shoulder (r = -0.374, p < 0.05). However, there was no correlation between radiographic distance ratios and clinical evaluation scores. CONCLUSION: We strongly recommend ultrasonography as a diagnostic tool to measure the degree of shoulder subluxation in patients with post-stroke hemiplegia.     

Primary Adenocarcinoma in the Urethrorectal Fistula

A 60-year-old Japanese man was hospitalized because of urinary leakage from the anus on October 3, 1994. Retrograde urethrography detected a fistula between the bulbous urethra and the rectum. Urethrocystoscopy revealed a tumor on the urethrorectal fistula. Tumor biopsy showed a well differentiated adenocarcinoma. Cystourethrectomy with fistulectomy, and ileal conduit urinary diversion were performed. Pathological examination revealed primary adenocarcinoma in the fistula with invasion to the prostatic urethra and bladder wall. The patient showed no evidence of a recurrence as of August, 1996.     

Prediction of spinal cord ischemia with a retrievable stent graft on endovascular treatment for a case of thoracic aortic aneurysm

Multiple aortic aneurysms in Behçet’s disease were repaired with transluminaly placed endovascular stent grafts. Before deploying the stent graft device for permanent implantation for the saccular aneurysm located in the descending thoracic arota, from which feeding arteries for the spinal cord possibly branched, a retrievable stent graft was inserted and evoked spinal cord potential (ESP) were monitored in order to predict spinal cord ischemia. The original retrievable stent graft, constructed of a self-expandable Z-shaped stainless steel stent covered with e-PTFE, can be easily withdrawn into a 18 Fr. sheath after deployment. Blood flow into intercostal arteries branching from that part of the descending aorta where the permanent stent graft is planned to be implanted, is intercepted by the retrievable stent graft. A change of ESP during the temporary implantation of the device indicates that spinal cord ischemia would be caused by permanent implantation of the stent graft. In this case, no change of ESP was observed and the patient showed no postoperative paraplegia.The retrievable stent graft was useful for prediction of spinal cord ischemia before endoluminal stent graft repair of the descending aortic aneurysm. However, the device is not flexible enough to fit a severely tortuous aorta, therefore we are obliged to select patients to some extent. Further improvement of the device is required to make prediction of spinal cord ischemia with the retrievable stent graft possible in all cases.