Does stent placement improve the results of ineffective or complicated iliac artery angioplasty?

OBJECTIVE: This study was undertaken to determine the results and complications of stents placed for initially unsuccessful or complicated iliac percutaneous transluminal angioplasty (PTA), the effect of location (external iliac or common iliac) on outcome, and the influence of superficial femoral artery patency on benefit. DESIGN: From 1992 through 1997, 350 patients underwent iliac artery PTA at the authors' institutions. Of this group, 88 patients (88 arteries) had one or more stents placed after PTA (140 stents in total) for residual stenosis or pressure gradient (63 patients), iliac dissection (12 patients), long-segment occlusion (10 patients), or recurrent stenosis (3 patients). Thirty patients required the placement of more than one stent. The indications for PTA in these 88 patients were claudication (48 patients) and limb-threatening ischemia (40 patients). Forty-seven patients had stents placed in the common iliac, 29 patients had stents placed in the external iliac, and 12 patients had stents placed in both. Seventy-one arteries (81%) were stenotic, and 17 (19%) were occluded before PTA. Sixty-six arteries were treated by interventional radiologists, 15 by a vascular surgeon, and 7 jointly. MAIN OUTCOME MEASURE: Criteria for success included (1) increase of at least one clinical category of chronic limb ischemia from baseline or satisfactory wound healing, (2) maintenance of an ankle/brachial index increase of more than 0.10 above the preprocedure index, and (3) residual angiographic stenosis less than 25% and, for patients with pressure gradient measurements, a residual gradient less than 10 mm Hg. RESULTS: Stent placement was accomplished in all 88 patients with 16 (18%) major complications. Mean follow-up was 17 months (range, 3 to 48 months). By life-table analysis, success was 75% at 1 year, 62% at 2 years, and 57% at 3 years. No cardiovascular risk factor or independent variable was statistically significant in predicting success. There was no difference in success rates for common iliac or external iliac lesions. Superficial femoral artery patency did not correlate with outcome. CONCLUSIONS: Although stents can eliminate residual lesions and arterial dissection, these patients are likely to require adjuvant or subsequent procedures to attain clinical success. By controlling the PTA complication and treating the emergent problem, stents may allow for subsequent elective intervention.     

Predominance of slow acetylators of N-acetyltransferase in a Hmong population residing in the United States

Pharmacogenetics can be an important determinant of pharmacologic response. To learn more about interpopulation differences in drug metabolism between ethnically diverse populations of subjects cared for by an International Clinic, a study was conducted to describe the prevalence of fast or slow acetylators of N-acetyltransferase (NAT2) in a population of Hmong residing in Minnesota. Ninety-eight healthy Hmong refugees from Laos volunteered to take caffeine as an oral probe drug to establish acetylator phenotype. Participants were classified as either rapid or slow acetylators based on the urinary molar ratio of select metabolites of caffeine. Assignment of phenotype was based on results from analysis of urine collected subsequent to ingestion of caffeine. The ratio of 5-acetylamino-6-formylamino-3-methyluracil (AFMU) to the combined products of the 7-demethylation pathway of paraxanthine (AFMU, 1-methylxanthine (1X), and 1-methylurate (1U)] formed the basis for this determination. A probit plot of the data collected in our subjects qualified a metabolic ratio of 0.34 as an acceptable cut point for phenotype assignment. Participants with an AFMU/(AFMU + 1X + 1U) ratio of < 0.34 were classified as slow acetylators and all others as rapid acetylators. Analysis of the data suggested a bimodal distribution with an excess (74.5%) of slow acetylators in the population. The predominance of slow acetylators found in the Hmong contrast with the prevalence of slow acetylators seen in other ethnic groups. These findings may have important clinical implications given the large number of Hmong treated each year in our International Clinic and the increasing use of medications metabolized by NAT2 in this population.     

Peutz-Jeghers polyposis with metastasizing duodenal carcinoma

A case of Peutz-Jeghers polyposis associated with duodenal carcinoma but without cutaneous pigmentation was presented. Duodenal carcinoma is the most commonly associated neoplasm. The presence of vitiligo in this patient is coincidental. Of 14 reported cases of Peutz-Jeghers syndrome associated with intestinal carcinoma, in only two was the tumor shown to originate in the polyp. In our case, too, we believe the carcinoma developed independently.     

Molecular structure and morphology of glycogen isolated from the cestode, Moniezia expansa

Intravenous administration of 125I-hCG to 7-8 day pseudopregnant rats resulted in maximum uptake of radioactivity to corpora lutea 2 hours after treatment. At this time tissue/plasma radioactivity ratios on an equal weight basis were: corpora lutea, 70.2 +/- 12.8; ovarian interstitium, 4.6 +/- 0.2; kidney, 2.2 +/- 0.1. No appreciable uptake was seen by adrenals or liver. Radioactivity in corpora lutea was associated primarily with membranes which sedimented at 2000g and when released by heat it was more than 63% bound to luteal LH receptor preparation in vitro. Radioactivity in renal tissue was associated primarily with the 100,000g supernatant fraction and was bound less than 1% to luteal LH receptors in vitro. PGF2alpha significantly reduced uptake (p less than .001) of 125I-hCG by corpora lutea within 30 minutes (-63%) as well as at 1 (-64%), 2 (-75%), 4 (-68%) and 24 hours (-85%). No clear effect of PGF2alpha on uptake of 125I-hCG by ovarian interstitial tissue was seen. Plasma progesterone was significantly decreased (p less than .001) within 30 minutes (-47%; p less than .01) after PGF2alpha treatment and also at 1 (-65%), 2 (-82%), 4 (-68%) and 24 hours (-92%). Two hours after PGF2alpha treatment the content of progesterone in corpora lutea was depressed (-46%; p less than .001). It is suggested that the rapid inhibition of luteal progesterone production induced by PGF2alpha in vivo occurs through a block in gonadotropin uptake by corpora lutea.     

Clinical applications of functional MRI in neuropsychiatry

Clinical neuroimaging is due for yet another sea change as functional neuroimaging becomes increasingly powerful and available. Functional magnetic resonance imaging (fMRI) is perhaps the most promising of the emerging techniques. The following review helps us understand the physics, strengths, limitations, and promise of fMRI. The authors are all affiliated with the Brain Imaging Center at McLean Hospital and with the Departments of Neurology (Dr. Levin) and Psychiatry (Dr. Renshaw) at Harvard Medical School.