Elective stenting of the extracranial carotid arteries

BACKGROUND

Surgical endarterectomy has been shown to be superior to medical management in the management of severe carotid stenosis in both symptomatic and asymptomatic patients. Endarterectomy, although effective, does have limitations, and percutaneous techniques may offer an alternative method of treatment.

METHODS AND RESULTS

The feasibility and safety of percutaneous carotid angioplasty and elective (primary) stenting was evaluated prospectively in a consecutive series of 107 patients. One hundred twenty-six carotid arteries with significant stenosis were treated. This series represented a high-risk subset that included patients with previous ipsilateral endarterectomy and severe medical comorbidity. Forty-five percent of the patients were referred by surgeons. Patients had independent neurological examinations before and after the procedure and follow-up cerebral angiography at 6 months. The mean (+/- SD) stenosis was reduced from 78 +/- 14% to 2 +/- 5%. There were 7 minor strokes, 2 major strokes, and 1 death during the initial hospitalization and first 30 days after the procedure. For the combined end point of all strokes and death, the incidence was 7.9%. For ipsilateral major stroke and death, the incidence was 1.6%. There were no strokes during the follow-up period. Mean angiographic stenosis at 6 months in 81 patients was 18 +/- 16% (range, -21% to 57%). Four (4.9%) of these 81 patients had asymptomatic restenosis. Five asymptomatic patients had repeat intervention: 2 had angioplasty for restenosis, 2 had angioplasty for stent deformation, and 1 had endarterectomy for restenosis.

CONCLUSIONS

In a high-risk group of patients, percutaneous carotid angioplasty and stenting are feasible and can be performed with low restenosis and repeat intervention rates.

Tyrosine phosphorylation of myelin protein PO

Po (M(r) 30 kDa), the major protein component of peripheral nervous system (PNS) myelin, is known to be phosphorylated by protein kinase C on serine residues at multiple sites. This study was conducted to assess whether other amino acids might be phosphorylated in the protein. Segments of rat sciatic nerve were incubated with 32P in either the presence or absence of phorbol ester. Labeled Po was isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subjected to partial acid hydrolysis. Upon separation of the hydrolysis products by either thin-layer electrophoresis or thin-layer chromatography, a radioactive spot was detected which comigrated with authentic phosphotyrosine. In other experiments, nerves were incubated with the tyrosine phosphatase inhibitors vanadate or vanadyl hydroperoxide (pervanadate). When the nerve homogenate proteins were separated on gels and probed with a monoclonal antibody to phosphotyrosine on Western blots, a positive immune reaction was obtained for a protein species which migrated with the same mobility as PO on Coomassie Blue-stained gels. In the absence of 2-mercaptoethanol, this immunoreactive band displayed increased mobility on gels which is characteristic of the migration pattern of Po. The same immunostaining results were obtained using a purified peripheral myelin fraction prepared from nerve homogenates. Furthermore, the positions of immunoreactive bands produced by anti-Po and antiphosphotyrosine antibodies coincided on the same immunoblot of myelin proteins and purified Po. These data indicate that one or more tyrosyl residues in Po can be phosphorylated in intact sciatic nerve.

Differences in mannose receptor-mediated uptake of lipoarabinomannan from virulent and attenuated strains of Mycobacterium tuberculosis by human macrophages

Phagocytosis of the virulent Erdman and H37Rv strains of Mycobacterium tuberculosis, but not that of the attenuated H37Ra strain, by human macrophages is mediated by the mannose receptor (MR) in addition to complement receptors. We have recently determined that a major capsular lipoglycan, lipoarabinomannan (LAM), from the Erdman strain serves as a ligand for the MR during phagocytosis of bacteria. In this study we directly compare uptake of Erdman, H37Rv, and H37Ra LAM by human macrophages and assess the relative contribution of the MR in this process. Microspheres coated with LAM served as model phagocytic particles for studies of LAM as a capsular ligand. Uptake (37 degrees C) of LAM microspheres by monocyte-derived macrophages was greatest for Erdman LAM and intermediate for H37Rv and H37Ra LAM compared with that of buffer microspheres or microspheres coated with LAM from a nontuberculosis strain of mycobacterium (AraLAM). Inhibition of microsphere uptake in the presence of mannan or mannose-BSA was highest for Erdman LAM (75 +/- 8 and 50 +/- 7%, respectively) and H37Rv LAM (57 +/- 13 and 21 +/- 5%, respectively) relative to H37Ra LAM (36 +/- 16 and 22 +/- 11 %, respectively). Inhibition of microsphere uptake in the presence of anti-MR Ab followed a similar pattern: Erdman LAM (80 +/- 9%) > H37Rv LAM (53 +/- 1%) > H37Ra LAM (26 +/- 12%). Attachment (4 degrees C) of microspheres coated with Erdman LAM, H37Rv LAM, and H37Ra LAM was enhanced 12-, 5-, and 4-fold, respectively, compared with that of microspheres coated with AraLAM, and mannose-BSA inhibited attachment of these microspheres by 82 +/- 7, 69 +/- 8, and 12 +/- 17%. Galactose-BSA did not inhibit attachment of any LAM microsphere groups. Chromatographic analyses of mild acid hydrolysates of LAM from Erdman, H37Rv, and H37Ra all revealed the major terminal dimannosyl units. These studies demonstrate differences in the ability of LAM from different M. tuberculosis strains to mediate adherence to macrophages and to serve as ligands for the macrophage MR despite the presence of terminal dimannosyl units. Thus, these studies point toward other subtle structural alterations in LAM among strains that influence initial interactions with human phagocytes.

Differences in mannose receptor-mediated uptake of lipoarabinomannan from virulent and attenuated strains of Mycobacterium tuberculosis by human macrophages

Phagocytosis of the virulent Erdman and H37Rv strains of Mycobacterium tuberculosis, but not that of the attenuated H37Ra strain, by human macrophages is mediated by the mannose receptor (MR) in addition to complement receptors. We have recently determined that a major capsular lipoglycan, lipoarabinomannan (LAM), from the Erdman strain serves as a ligand for the MR during phagocytosis of bacteria. In this study we directly compare uptake of Erdman, H37Rv, and H37Ra LAM by human macrophages and assess the relative contribution of the MR in this process. Microspheres coated with LAM served as model phagocytic particles for studies of LAM as a capsular ligand. Uptake (37 degrees C) of LAM microspheres by monocyte-derived macrophages was greatest for Erdman LAM and intermediate for H37Rv and H37Ra LAM compared with that of buffer microspheres or microspheres coated with LAM from a nontuberculosis strain of mycobacterium (AraLAM). Inhibition of microsphere uptake in the presence of mannan or mannose-BSA was highest for Erdman LAM (75 +/- 8 and 50 +/- 7%, respectively) and H37Rv LAM (57 +/- 13 and 21 +/- 5%, respectively) relative to H37Ra LAM (36 +/- 16 and 22 +/- 11 %, respectively). Inhibition of microsphere uptake in the presence of anti-MR Ab followed a similar pattern: Erdman LAM (80 +/- 9%) > H37Rv LAM (53 +/- 1%) > H37Ra LAM (26 +/- 12%). Attachment (4 degrees C) of microspheres coated with Erdman LAM, H37Rv LAM, and H37Ra LAM was enhanced 12-, 5-, and 4-fold, respectively, compared with that of microspheres coated with AraLAM, and mannose-BSA inhibited attachment of these microspheres by 82 +/- 7, 69 +/- 8, and 12 +/- 17%. Galactose-BSA did not inhibit attachment of any LAM microsphere groups. Chromatographic analyses of mild acid hydrolysates of LAM from Erdman, H37Rv, and H37Ra all revealed the major terminal dimannosyl units. These studies demonstrate differences in the ability of LAM from different M. tuberculosis strains to mediate adherence to macrophages and to serve as ligands for the macrophage MR despite the presence of terminal dimannosyl units. Thus, these studies point toward other subtle structural alterations in LAM among strains that influence initial interactions with human phagocytes.

Angioplasty and stenting for restenosis after carotid endarterectomy. Initial experience

BACKGROUND AND PURPOSE

Endarterectomy for recurrent carotid stenosis after endarterectomy has a significantly higher complication rate than the original operation. Angioplasty and stenting may offer a useful alternative treatment for these patients.

METHODS

Between September 1994 and April 1996, 22 patients had 25 carotid arteries treated with angioplasty and stenting for postendarterectomy restenosis. All patients had an independent neurological examination and National Institutes of Health Stroke Scale evaluation before and after the procedure. Patients were treated with aspirin and ticlopidine. All patients were requested to return at 6 months for follow-up angiography. The mean patient age was 69 +/- 7 years, and the mean elapsed time from endarterectomy was 73 +/- 69 months. Seventy-seven percent of the patients were symptomatic.

RESULTS

Mean stenosis was reduced from 79 +/- 13% before the procedure to 1.8 +/- 3.6% after stenting. One patient had a minor stroke, for a complication rate of 4% per treated artery. In the eight patients who returned for 6-month angiography, mean stenosis was 19.4 +/- 4.4% and restenosis (> or = 50% stenosis) did not occur.

CONCLUSIONS

In a small series, angioplasty and stenting appear to be safe and well tolerated for the treatment of postendarterectomy restenosis.

Supernumerary limbs: a case report of a rare congenital anomaly

We report a case of an 18-month-old female who presented with three supernumerary upper limbs of varying lengths on the right side. Each limb had a proximal, middle, and distal segment, and an intercalated elbow and wrist joint. A single digit was present in the superior limb, three digits in the middle limb, and two digits in the caudal-most limb. Right plagiocephaly, congenital torticollis, scoliosis involving the upper and mid thoracic region, and a hypoplastic right pectoralis major were the other abnormal features noted. Radiography showed two scapulae, humerus, a single forearm bone in each limb, and rudimentary metacarpals and phalanges. Limb duplication may rarely be encountered in parasitic conjoined twins. The role of mutagens, drugs, cellular contributions, and morphogens in the growth and differentiation of limbs has been studied in animals. It is rather difficult to deduce the time of action of the factors responsible for such a malformation.

Reduction of thrombus formation without inhibiting coagulation factors does not inhibit intimal hyperplasia after balloon injury in pig coronary arteries

BACKGROUND

The proposed mechanisms of restenosis after coronary angioplasty include neointima formation, vessel wall remodeling and mural thrombus. Poloxamer 188 does not inhibit coagulation factors, but was shown to reduce mural thrombus formation in pig coronary arteries after intracoronary stenting in an acute study. This study was performed to examine whether this agent may reduce neointima formation.

METHODS

Thirty domestic juvenile pigs of weight 20-30 kg were anesthetized. A left angiogram was performed via a femoral artery. Proximal left anterior descending and circumflex arteries were dilated three times with a 20-30% oversized coronary angioplasty balloon catheter. Fifteen animals were allocated randomly to receive intravenous infusions of poloxamer 188, starting 30 min before angioplasty and continuing for 24 h. The remaining 15 received intravenous 0.45% saline and served as controls. The animals were killed 2 weeks after the angioplasty. Histologic studies of the arteries were performed. The severity of the injury and the amount of thrombus material incorporated in the neointima were assessed by semiquantitative methods.

RESULTS

There was no significant difference between injury scores in the two groups. Thrombus material in the neointima in the treatment group was significantly less than that in those of the control group (thrombus areas 0.013 +/- 0.004 compared with 0.029 +/- 0.006 mm2, P < 0.02), but there were no significant differences between the neointimal (0.60 +/- 0.08 and 0.60 +/- 0.13 mm2) and luminal (2.51 +/- 0.21 and 2.44 +/- 0.26 mm2) areas in treatment and control groups.

CONCLUSION

Continuous 24 h intravenous infusion of poloxamer 188 after balloon injury in pig coronary arteries may reduce mural thrombus formation significantly, but did not reduce neointima formation.

Phosphorylation of myelin protein: recent advances

Since it was first described 25 years ago, phosphorylation has come to be recognized as a widespread and dynamic post-translation modification of myelin proteins. In this review, the phosphorylation characteristics of myelin basic protein, protein zero (P0), myelin-associated glycoprotein and 2'3' cyclic nucleotide 3'-phosphodiesterase are summarized. Emphasis is placed on recent advances in our knowledge concerning the protein kinases involved and the sites of phosphorylation in the amino acid sequences, where known. The possible roles of myelin protein phosphorylation in modulating myelin structure, the process of myelin assembly and mediation of signal transduction events are discussed.

Lactoferrin: molecular structure and biological function

Lactoferrin is an 80-kDa, iron-binding glycoprotein present in milk and, to a lesser extent, in exocrine fluids such as bile and tears. It consists of a single-chain polypeptide with two gobular lobes and is relatively resistant to proteolysis. The complete cDNAs for lactoferrin from human milk, neutrophils, and bovine milk have been reported, and recombinant proteins have been produced. Owing to its iron-binding properties, lactoferrin has been proposed to play a role in iron uptake by the intestinal mucosa and to act as a bacteriostatic agent by withholding iron from iron-requiring bacteria. Its presence in neutrophils and its release during inflammation suggest that lactoferrin is also involved in phagocytic killing and immune responses. Additionally, lactoferrin may function in ways not related to iron-binding, e.g. as a growth factor and as a bactericidal agent. This review attempts to evaluate these proposed functions and their biological significance in more detail.

Association of gastroesophageal reflux (GER) with bronchial asthma

Eighty children with bronchial asthma and ten control cases underwent radionuclide gastroesophagography for the detection of gastroesophageal reflux. Thirty nine per cent asthmatic children demonstrated esophageal reflux on scintiscanning. The ten control subjects had no reflux. The presence of reflux correlated strongly with the presence of nocturnal exacerbation of symptoms. Bronchodilator therapy did not affect the prevalence of GER in asthmatic children.

Lactoferrin: molecular structure and biological function

Lactoferrin is an 80-kDa, iron-binding glycoprotein present in milk and, to a lesser extent, in exocrine fluids such as bile and tears. It consists of a single-chain polypeptide with two gobular lobes and is relatively resistant to proteolysis. The complete cDNAs for lactoferrin from human milk, neutrophils, and bovine milk have been reported, and recombinant proteins have been produced. Owing to its iron-binding properties, lactoferrin has been proposed to play a role in iron uptake by the intestinal mucosa and to act as a bacteriostatic agent by withholding iron from iron-requiring bacteria. Its presence in neutrophils and its release during inflammation suggest that lactoferrin is also involved in phagocytic killing and immune responses. Additionally, lactoferrin may function in ways not related to iron-binding, e.g. as a growth factor and as a bactericidal agent. This review attempts to evaluate these proposed functions and their biological significance in more detail.

The use of Gianturco-Roubin flexible metallic coronary stents in old saphenous vein grafts: in-hospital outcome and 7 day angiographic patency

After placement of a Gianturco-Roubin metallic, coiled coronary stent(s) following balloon angioplasty (PTCA), a pre-discharge (7 day) angiogram determined the patency of the old coronary bypass vein graft(s) (SVG) (> or = 5 years remote from their last surgery, mean age: 8.5 +/- 1.8 years). Metallic, coiled stents were successfully deployed in 95/96 (99%) patients within 100/101 (99%) SVGs. The indications for deployment were threatened [81 patients (84%)] or acute [15 patients (16%)] vein graft closure following PTCA. Intragraft urokinase infusion was performed in 17 patients (17%) [6 patients with baseline occlusions; 11 with abrupt closure post PTCA]. Complications encountered included three (3%) in-hospital deaths (two procedure related) two (2%) Q wave myocardial infarctions, six (6%) non-Q wave myocardial infarctions, and 22 (22%) bleeding problems. These included, not mutually exclusively, 21 (22%) requiring transfusions, six (6%) cases of gastrointestinal bleeding, six (6%) pseudoaneurysms, five (5%) retroperitoneal haemorrhages and two (2%) cerebrovascular accidents. All patients received dipyridamole, aspirin, dextran, and anticoagulation (heparin 10-20,000 U intra-procedurally); a heparin infusion was continued for 5 +/- 1 days, despite warfarin administration which attained a therapeutic prothrombin time (PT) (1.5-2 times control) by 3 +/- 1 days. Out of the 95 successfully treated patients, six with eight stented grafts were ineligible for pre-discharge angiography. Of the six, three died in hospital (four SVGs), one had an intracerebral haemorrhage (one SVG), and two were asymptomatic patients with chronic renal failure (three SVGs).(ABSTRACT TRUNCATED AT 250 WORDS)

Sizing the Gianturco-Roubin coronary flexible coil stent

The balloon expandable, stainless steel, flexible coil stent is a useful device for the management of acute or threatened closure after percutaneous transluminal coronary angioplasty. Appropriate sizing is important to optimize immediate results and reduce the risk of acute thrombosis and restenosis. The in vivo size at deployment of this stent at nominal inflation pressures has not been evaluated. Forty patients who received a single flexible coil stent (10 patients each for stent sizes 4.0, 3.5, 3.0, and 2.5 mm) were studied. The stents were deployed at 3-5 atmospheres. The actual stent size achieved by the stent during deployment was found to be significantly less than the nominal size, being 3.7 +/- 0.3, 3.2 +/- 0.2, and 2.8 +/- 0.2 mm for nominal stent sizes of 4.0, 3.5, and 3.0 mm, respectively (P < 0.005, P < 0.001, and P < 0.01). For a 2.5 mm stent, it was 2.4 +/- 0.2 mm (P = ns). Thus, for optimal results with this device, we recommend that vessels 2.0-2.4 mm in diameter be supported by a 2.5 mm stent, vessels 2.5-2.9 mm in diameter by a 3.0 mm stent, vessels 3.0-3.4 mm in diameter by a 3.5 mm stent, and vessels 3.5-4.0 mm in diameter by a 4.0 mm stent.

Acute appendicitis mistaken as acute rejection in renal transplant recipients

Case histories of 2 renal transplant recipients are reported who had presenting features of fever, leukocytosis and pain/tenderness over right iliac fossa and were diagnosed to be due to acute appendicitis rather than more commonly suspected acute rejection episode which has very similar features. Diagnosis of acute appendicitis was suspected on the basis of rectal examination and later confirmed by laparotomy. The purpose of this communication is to emphasize the need for proper diagnosis in patient with such presentation; otherwise wrong treatment may be received.

The impact of balloon angioplasty of coronary artery and/or vein bypass graft lesion(s) upon the survival of patients > or = 5 years after their last bypass surgery

Data analyses of angioplasty patients, whose operative and angioplasty (PTCA) interval was > or = 5 years, were performed to determine if the site of PTCA (coronary artery (CA) and/or vein bypass graft (VG)) influenced longevity. PTCA was successful in 677/768 lesions (88%) (377/432 CA (87%), and 294/327 VGs (90%)) and resulted in clinical improvement in 280/322 patients (87%). Patients were stratified into those who underwent PTCA of a lesion(s) in a coronary artery only, a vein graft only, or in both a coronary artery and a vein graft. Survival, at 60 months, was adversely affected (P < 0.05) for VG (59%) in comparison to CA (86%) or CA + VG (86%) cohorts, which was reaffirmed by a Cox proportional hazard model. PTCA was effective in opening lesions in coronary arteries or vein grafts in patients whose last bypass surgery had occurred over 5 years previously; however, PTCA patients who only had a vein graft had a significantly diminished 5-year survival in comparison to the cohorts, who had a coronary artery lesion dilated, with or without an accompanying vein graft PTCA. Therefore, PTCA of isolated vein graft lesions may not be the best long-term therapeutic option for these patients; however, it may best serve patients, acutely and long-term, who have an amenable significant arterial lesion, whether or not an accompanying vein graft lesion is dilated.

Isolated posterior dislocation of the radial head in an adult

Isolated posterior dislocation of the radial head was detected on X-ray in a patient following a vehicular accident. Such a dislocation without an associated fracture is extremely rare in adults. Immobilization of the elbow in full pronation and 90 degrees flexion for 4 weeks normalized the position of the head of the radius.