Selamectin is a potent substrate and inhibitor of human and canine P-glycoprotein

The transport of the antiparasitic agents, ivermectin, selamectin and moxidectin was studied in human intestinal epithelial cell monolayers (Caco-2) and canine peripheral blood lymphocytes (PBL). Both models expressed the mdr1-coded 170 kDa ATP-binding cassette (ABC) transporter P-glycoprotein (P-gp). Fluxes of the P-gp substrate rhodamine-123 (Rh-123) across Caco-2 monolayers showed that ivermectin and selamectin acted as potent P-gp inhibitors with IC50 values of 0.1 microm. In contrast, moxidectin was a weaker P-gp inhibitor with an IC50 of 10 microm. The transport of radiolabelled ivermectin, selamectin and moxidectin through Caco-2 monolayers showed that ivermectin, selamectin and moxidectin were P-gp substrates with secretory/absorptive ratios of 7.5, 4.7 and 2.6 respectively. Secretory transport of [3H]-ivermectin and [3H]-selamectin was blocked by the P-gp inhibitor, verapamil. Ivermectin and selamectin inhibited the efflux of Rh-123 from PBL and the concentration of inhibition was similar to that of verapamil. In contrast, moxidectin did not have a significant effect on Rh-123 efflux from PBL. The data suggest that ivermectin and selamectin are potent P-gp substrates, while moxidectin is a weak one.

Comparison of end-tidal and transcutaneous measures of carbon dioxide during general anaesthesia in severely obese adults

BACKGROUND

Patients with severe obesity (body mass index (BMI) greater than 35 kg x m(-2)) present difficulties for end-tidal carbon dioxide (FE'(CO(2))) monitoring. Previous studies suggest that transcutaneous (TC) carbon dioxide measurements could be valuable, so we compared FE' and TC measures with Pa(CO(2)) in severely obese patients during anaesthesia.

METHODS

We studied patients with severe obesity (BMI >or=40 kg x m(-2)) undergoing gastric bypass surgery. Carbon dioxide was measured with both FE' and TC devices. The difference between each measure (FE'(CO(2)) and TC-CO(2)) and the Pa(CO(2)) was averaged for each patient to provide one value, and data compared with a non-paired, two-way t-test, Fisher's exact test.

RESULTS

We studied 30 adults (aged 18-54 yr, mean 41, SD 8.0 yr; weight: 115-267 kg, mean 162, SD 35 kg). The absolute difference between the TC-CO(2) and Pa(CO(2)) was 0.2 (0.2) (mean, SD) kPa while the absolute difference between the FE'(CO(2)) and Pa(CO(2)) was 0.7 (0.4) kPa (P<0.0001). The bias and precision were +0.1 (0.3) kPa for TC vs arterial carbon dioxide and -0.7 (0.4) kPa for FE' vs arterial carbon dioxide.

CONCLUSIONS

Transcutaneous carbon dioxide monitoring provides a better estimate of Pa(CO(2)) than FE'(CO(2)) in patients with severe obesity.

A modern day holy anorexia? Religious language in advertising and anorexia nervosa in the West

OBJECTIVE

In this review we comment on the media, in particular advertisements and the internet, using religious and moralistic motifs in connection with eating and their possible role in promoting modern-day 'nutritional' consumerism and fundamentalism (diet, discipline and discipleship).

METHOD

We have reviewed historically the concept of holy anorexia and have analyzed the pictorial and language content of some representative advertisements.

RESULTS

Words used include 'temptation', 'decadent', 'heaven' and 'purity' and suggest a connection with eating and moral values. They also imply eating as either heaven or sin, to be yielded to in both circumstances.

CONCLUSIONS

Such messages identifying eating with guilt or reward could precipitate 'atypical' eating disorders in vulnerable subjects, invoking the historical associations with extreme religiosity and anorexia. It is not clear how these 'fundamentalist' trends developed but health educators should be aware of them in dealing with at-risk subjects for eating disorders.

The effects of a home exercise program on pain and perceived dysfunction in a woman with TMD: a case study

There are few reports analyzing the effects of exercise on patients with temporomandibular disorders. This paper presents a case study examining whether there were additional benefits from performing neuromuscular control home exercises (NMCHE) in a patient with temporomandibular disorder who was already receiving conventional treatment. A woman, 41 years of age, completed a health status questionnaire called the TMJ Scale prior to being accepted. She completed additional TMJ Scales after receiving conventional treatment and again after conventional treatment was combined with neuromuscular control home exercises. Based on the TMJ Scale's best subscore indicator of the presence or absence of a temporomandibular disorder, the patient did not derive benefit from conventional treatment without exercise. However, she received a large benefit from the addition of NMCHE. It was concluded that exercises for patients with temporomandibular disorders may be beneficial to those who do not improve with conventional treatment alone.

The biology of signal transduction inhibition: basic science to novel therapies

Developing drugs to specifically inhibit oncogenes has been a major goal of cancer research for many years. Identifying the appropriate intracellular targets and understanding the signal transduction pathways in which these molecules participate are critical to this process. A large number of the activated oncogenes implicated in the pathogenesis and progression of malignancy are tyrosine kinases. Bcr-Abl, the causative molecular abnormality in chronic myeloid leukemia (CML), is a prototypic oncogenic kinase and an attractive drug target. The tyrosine kinase inhibitor imatinib mesylate (formerly STI571, [Gleevec]; Novartis Pharmaceuticals Corp, East Hanover, NJ) was recently approved for the treatment of CML and provides proof of principle for the strategy of targeted signal transduction inhibition. This drug is effective in the chronic phase of CML, a single gene disorder driven by Bcr-Abl, and in the advanced phases of CML, showing that inhibition of a single oncogene in a multigene disorder also may be of benefit. The success of imatinib mesylate in CML led rapidly to clinical trials in other cancers associated with activation of two other tyrosine kinases known to be sensitive to imatinib mesylate, c-Kit and the platelet-derived growth factor receptor. Gastrointestinal stromal tumors, which have activating mutations in c-Kit, are now also being found to respond to kinase inhibition with the drug. The general approach of specifically targeting activated kinases with small-molecule drugs is likely to be effective in other tumors in the future.

Normal flow (TIMI-3) before mechanical reperfusion therapy is an independent determinant of survival in acute myocardial infarction: analysis from the primary angioplasty in myocardial infarction trials

BACKGROUND

Whereas survival after lytic therapy for myocardial infarction is strongly dependent on early administration, it is unknown whether the otherwise excellent outcomes in patients undergoing primary PTCA for acute myocardial infarction, in whom TIMI-3 flow rates of >90% may be achieved, can be further improved by early reperfusion.

METHODS AND RESULTS

Among 2507 patients enrolled in 4 PAMI trials undergoing primary PTCA, spontaneous reperfusion (TIMI-3 flow) was present in 16% at initial angiography. Compared with patients without TIMI-3 flow, those with TIMI-3 flow before PTCA had greater left ventricular ejection fraction (57+/-10% versus 53+/-11%, P=0.003) and were less likely to present in heart failure (7.0% versus 11.6%, P=0.009). Patients with initial TIMI-3 flow had significantly lower in-hospital rates of mortality, new-onset heart failure, and hypotension and had a shorter hospital stay. Cumulative 6-month mortality was 0.5% in patients with initial TIMI-3 flow, 2.8% with TIMI-2 flow, and 4.4% with initial TIMI-0/1 flow (P=0.009). By multivariate analysis, TIMI-3 flow before PTCA was an independent determinant of survival (odds ratio 2.1, P=0.04), even when corrected for by postprocedural TIMI-3 flow.

CONCLUSIONS

Patients undergoing primary PTCA in whom TIMI-3 flow is present before angioplasty present with greater clinical and angiographic evidence of myocardial salvage, are less likely to develop complications related to left ventricular failure, and have improved early and late survival. These data warrant prospective randomized trials of pharmacological strategies to promote early reperfusion before definitive mechanical intervention in acute myocardial infarction.

Effect of soft lumbar support belt on abdominal oblique muscle activity in nonimpaired adults during squat lifting

STUDY DESIGN

A counterbalanced repeated measures design.

OBJECTIVE

To determine the effect of a soft lumbar support on abdominal oblique muscle electromyography (EMG) during lifting.

BACKGROUND

Use of a soft lumbar back support is a common preventive measure to reduce the incidence of back injuries. Because the abdominal oblique muscles stabilize the spine during lifting, wearing this support may alter the activity level of these muscles.

METHODS AND MEASURES

Twenty nonimpaired subjects (14 women and 6 men, mean age 28.9 +/- 8.1 years) were tested using surface electrodes to record the EMG of the right abdominal oblique muscles during lifting with and without the support.

RESULTS

A paired t test revealed a significant decrease in activity of the abdominal oblique muscles during lifting with the support (29.7 +/- 3.13 mV) compared to without it (33.3 +/- 3.05 mV). Of the 20 subjects, the 14 women showed decreased EMG amplitude during the lift with the lumbar support compared to without the support, while 5 of the men showed increased EMG amplitude with the support and 1 man showed no change.

CONCLUSION

This finding suggests that the soft lumbar support may play some role in the stabilization of the lumbar region during lifting.

Applications of gene replacement technology to Streptomyces clavuligerus strain development for clavulanic acid production

Cephamycin C production was blocked in wild-type cultures of the clavulanic acid-producing organism Streptomyces clavuligerus by targeted disruption of the gene (lat) encoding lysine epsilon-aminotransferase. Specific production of clavulanic acid increased in the lat mutants derived from the wild-type strain by 2- to 2.5-fold. Similar beneficial effects on clavulanic acid production were noted in previous studies when gene disruption was used to block the production of the non-clavulanic acid clavams produced by S. clavuligerus. Therefore, mutations in lat and in cvm1, a gene involved in clavam production, were introduced into a high-titer industrial strain of S. clavuligerus to create a double mutant with defects in production of both cephamycin C and clavams. Production of both cephamycin C and non-clavulanic acid clavams was eliminated in the double mutant, and clavulanic acid titers increased about 10% relative to those of the parental strain. This represents the first report of the successful use of genetic engineering to eliminate undesirable metabolic pathways in an industrial strain used for the production of an antibiotic important in human medicine.

Predisposition to hookworm infection in Papua New Guinea

Reinfection with hookworm (Necator americanus) following chemotherapy was studied over 8 years in a rural village in Madang Province, Papua New Guinea. Faecal egg counts were performed on up to 202 individuals in July 1988, August 1990 and November 1996; the study population was treated after sampling in 1988 and 1990. Reinfection burdens in 1996 did not differ significantly from pretreatment burdens (in 1988), and were significantly higher than burdens in 1990. However, the prevalence of hookworm infection was significantly lower in 1996 than in either 1988 or 1990. There was significant predisposition to high or low hookworm burden between 1990 and 1996; this predisposition was stronger in children than adults. However, there was no detectable predisposition between 1988 and 1996 in individuals who had been treated 2 or more times between surveys. The mean weight of adult hookworms in individual hosts was measured in 1988 and 1990 using worms expelled after chemotherapy. There was a significant positive correlation between mean male hookworm weight in the 2 years, suggesting that individual hosts are predisposed to infection with heavy or light hookworms. These data suggest that differences in host susceptibility are involved in generating predisposition, but that longer-term variation in either exposure or susceptibility limits the period over which significant predisposition can be detected.

Runaway pacemaker: a case report and review

We describe a case of runaway pacemaker. The differential diagnosis is discussed and a review of the literature is included for the diagnosis and treatment of pacemaker mediated tachycardia and runaway pacemaker.

Study of restriction fragment length polymorphism analysis and spoligotyping for epidemiological investigation of Mycobacterium bovis infection

Restriction fragment length polymorphism (RFLP) analysis with probes derived from the insertion element IS6110, the direct repeat sequence, and the polymorphic GC-rich sequence (PGRS) and a PCR-based typing method called spacer oligonucleotide typing (spoligotyping) were used to strain type Mycobacterium bovis isolates from the Republic of Ireland. Results were assessed for 452 isolates which were obtained from 233 cattle, 173 badgers, 33 deer, 7 pigs, 5 sheep, and 1 goat. Eighty-five strains were identified by RFLP analysis, and 20 strains were identified by spoligotyping. Twenty percent of the isolates were the most prevalent RFLP type, while 52% of the isolates were the most prevalent spoligotype. Both the prevalent RFLP type and the prevalent spoligotype were identified in isolates from all animal species tested and had a wide geographic distribution. Isolates of some RFLP types and some spoligotypes were clustered in regions consisting of groups of adjoining counties. The PGRS probe gave better differentiation of strains than the IS6110 or DR probes. The majority of isolates from all species carried a single IS6110 copy. In four RFLP types IS6110 polymorphism was associated with deletion of fragments equivalent in size to one or two direct variable repeat sequences. The same range and geographic distribution of strains were found for the majority of isolates from cattle, badgers, and deer. This suggests that transmission of infection between these species is a factor in the epidemiology of M. bovis infection in Ireland.

Ultrasound in obstetric triage

The use of limited ultrasound as a tool in obstetric triage has become increasingly popular. While most midwives only perform ultrasound in the third trimester, some institutions do include earlier sonographic testing as part of the midwifery management plan. This article addresses the professional issues related to limited ultrasound in obstetric triage protocol, the education and training needed to acquire the skill, the process for integrating the skill into clinical practice, and a discussion of obstetric triage procedures.

Guillain-Barré syndrome

The concepts of Guillain-Barré syndrome have changed substantially over the last 10 years, and the last 2 years have been no exception. Guillain-Barré syndrome is now recognized as a heterogeneous disorder with many clinical manifestations. Most current investigations are centered on the hypothesis of molecular mimicry. The major challenge now is to identify the precise mechanisms of nerve fiber injury and to determine how to prevent immune injury.

Cytosolic redox state mediates postischemic response to pyruvate dehydrogenase stimulation

Augmented pyruvate oxidation via pharmacological stimulation of pyruvate dehydrogenase (PDH) during reperfusion has been related to improved recovery of postischemic hearts independent of glycolytic activity. This study examined recovery of postischemic rabbit hearts during activation of PDH with dichloroacetate (DCA) in the presence of lactate, as a source of pyruvate, to determine the response to substrate-dependent changes in cytosolic redox state. After 10 min of ischemia, isolated hearts were reperfused with either 2.5 mM or 0. 5 mM pyruvate (Pyr) or 2.5 mM lactate (Lac), with or without 5 mM DCA. (13)C-enriched substrates allowed NMR assessment of metabolic perturbations. During normal perfusion, Pyr and Lac supported similar mechanical work. Increasing Pyr oxidation restored postischemic rate-pressure product to 82 +/- 4 and 88 +/- 6% of preischemic values during reperfusion with 2.5 and 0.5 mM Pyr, respectively, vs. 61 +/- 6 and 45 +/- 14% for untreated 2.5 and 0.5 mM Pyr, respectively (P < 0.05). In contrast, increasing Lac oxidation did not benefit recovery of RPP in untreated (44 +/- 7%) vs. DCA-treated 36 +/- 4% hearts. Thus the benefit of PDH activation for contractile recovery of postischemic hearts is mediated by the source of pyruvate, which also influences cytosolic redox state.

Predictors of homelessness among participants in a substance abuse treatment program

Risk factors for homelessness were examined prospectively among recent participants in a substance abuse treatment program. Low levels of support from friends, greater depression, and recent substance use were bivariately associated with homelessness two months following completion of the program. However, friend support was the only factor associated with homelessness after controlling for other significant bivariate predictors.

An analysis of silicone gel-filled breast implants: diagnosis and failure rates

This retrospective review analyzed 180 women who underwent explantation of 357 silicone gel-filled breast implants from September of 1991 to January of 1995. Implant status, including shell integrity and implantation times, was determined at the time of explantation. The age range of the patients was 25 to 75 years, with a mean age of 47 years. The age of the implants ranged from 0.5 to 24 years, with a mean age of 10.5 years. Of the 292 implants with known and documented integrity status, there were 102 intact, 76 unruptured with signs of leakage, and 114 ruptured. The frequency of implant rupture significantly increased with implant age. The average age of rupture was 13.4 years. The average age of signs of leakage was 10.1 years. There were no significant differences in failure rates among the implant types of four manufacturers. Analysis of both mammography and magnetic resonance imaging (MRI) as diagnostic modalities for differentiating intact implants, implant leakage, and implant rupture was performed. Standard mammography was less reliable in diagnosing implant leakage or rupture (sensitivity, 55 percent; specificity, 69 percent) than MRI (sensitivity, 72 percent; specificity, 82 percent). In conclusion, implant rupture occurred at a significantly increasing rate with implant age (10 to 15 years). These findings were independent of implant type or manufacturer. Mammography alone is a below-average diagnostic tool for detecting leakage or rupture, whereas MRI is a more accurate modality.

Safety and cost-effectiveness of early discharge after primary angioplasty in low risk patients with acute myocardial infarction. PAMI-II Investigators. Primary Angioplasty in Myocardial Infarction

OBJECTIVES

The second Primary Angioplasty in Myocardial Infarction (PAMI-II) study evaluated the hypothesis that primary percutaneous transluminal coronary angioplasty (PTCA), with subsequent discharge from the hospital 3 days later, is safe and cost-effective in low risk patients.

BACKGROUND

In low risk patients with myocardial infarction (MI), few data exist regarding the need for intensive care and noninvasive testing or the appropriate length of hospital stay.

METHODS

Patients with acute MI underwent emergency catheterization with primary PTCA when appropriate. Low risk patients (age <70 years, left ventricular ejection fraction >45%, one- or two-vessel disease, successful PTCA, no persistent arrhythmias) were randomized to receive accelerated care (admission to a nonintensive care unit and day 3 hospital discharge without noninvasive testing [n = 237] or traditional care [n = 234]).

RESULTS

Patients who received accelerated care had similar in-hospital outcomes but were discharged 3 days earlier (4.2+/-2.3 vs. 7.1+/-4.7 days, p = 0.0001) and had lower hospital costs ($9,658+/-5,287 vs. $11,604+/-6,125 p = 0.002) than the patients who received traditional care. At 6 months, accelerated and traditional care groups had a similar rate of mortality (0.8% vs. 0.4%, p = 1.00), unstable ischemia (10.1% vs. 12.0%, p = 0.52), reinfarction (0.8% vs. 0.4%, p = 1.00), stroke (0.4% vs. 2.6%, p = 0.07), congestive heart failure (4.6% vs. 4.3%, p = 0.85) or their combined occurrence (15.2% vs. 17.5%, p = 0.49). The study was designed to detect a 10% difference in event rates; at 6 months, only a 2.3% difference was measured between groups, indicating an actual power of 0.19.

CONCLUSIONS

Early identification of low risk patients with MI allowed safe omission of the intensive care phase and noninvasive testing, and a day 3 hospital discharge strategy, resulting in substantial cost savings.

Lead levels in high-risk and low-risk young children in the Minneapolis-St Paul metropolitan area

OBJECTIVES

To determine distribution of lead levels among children in a low-risk area; to validate a prescreening questionnaire; and to determine if universal lead screening is necessary in children in this area.

DESIGN

Blood lead levels and questionnaires were obtained on eligible patients. Data were analyzed using stepwise regression analysis.

SETTING

Community clinics and a health maintenance organization (HMO) in the Minneapolis-St Paul metropolitan area.

PATIENTS

A total of 9603 children at well-child visits, age 6 months to 6 years at community clinics, and 6 months to 3 years at the HMO.

OUTCOME MEASURES

Whole blood lead levels (WBLs) and questionnaires.

RESULTS

The total sample rate of WBLs at >/=10 microg/dL was 12%, at >/=15 microg/dL was 31/2%, and at >/=20 microg/dL was 1.2%. At both 10 microg/dL and 15 microg/dL, the non-HMO group was at higher risk. For both groups, risk factors included living in the central cities, and living in housing built before 1950. For the non-HMO group a history of the child eating paint chips, or the child or a sibling having previous lead poisoning were also risk factors.

CONCLUSIONS

Not all children need lead screening. Children living in the central cities, or with the risk factors of living in housing built before 1950 or a previous history of lead poisoning should be screened.

The modern CIO: forging a new role in the managed care era

The advent of managed care has helped forge new roles for healthcare professionals. Competitive pressures, the profile of the member community, and provider network design drive healthcare delivery via the managed care model. Careful analysis and design of the managed care model charts the success or failure of the health care delivery system--usually an integrated delivery system (IDS). Therefore, those healthcare organizations that have chosen to get on the managed care bandwagon must re-invent themselves, both culturally and technologically. The chief information officer (CIO) leads this technological revolution. To work effectively, the technological infrastructure of the IDS must be closely in line with enterprise goals and objectives. In the managed care environment the old information system (IS) approach of supporting the operational needs of individual departments simply will not work. The CIO's new role will be to master the concept of managed care to ensure that enterprise-wide needs for operational, clinical, and financial information are met, and that IS and enterprise goals are aligned. CIOs who have an intuitive grasp of the managed care environment--although their numbers are growing as managed care mushrooms--make up a minority group. They are a special breed with clearly definable qualities such as business savvy and an affinity for big-picture thinking. To an IDS, a CIO with these qualities is a rare gem indeed. This article introduces Don Winschel, the associate administrator and CIO of Johnson City Medical Center (Johnson City, TN) as an example of one such modern CIO.

Identification of a CG/LH binding site in two strains of Mycobacterium vaccae

We have previously reported the presence of a chorionic gonadotropin-like (CG-like) protein in the bacterium Xanthomonas maltophilia (X. maltophilia). We have also shown that X. maltophilia possesses a unique binding site for the native ligand and hCG, but not for human luteinizing hormone (hLH), and that binding of the native ligand or hCG to the receptor causes changes in the growth rates of culturing X. maltophilia. In this study we have characterized a CG/LH binding site in two strains of Mycobacterium vaccae. The binding site is specific for hCG and hLH, and Scatchard analysis reveals a biphasic, high affinity binding pattern. This is the second identified bacterial species to possess a CG-specific binding site.

New paradigms for new problems: expanding information technology in healthcare

As healthcare moves from individual fee-for-services and single hospital systems to capitated contracts and integrated delivery systems (IDS), and then into Community Health Information Networks (CHINs), implementing a data warehouse is a realistic way to collect and transform data into meaningful information. However, healthcare differs from other industries because of its complexity. The software is more specialized, and many vendors have adopted proprietary operating systems that hold critical data hostage. Even when available, data is not integrated and is more convoluted than in other industries. To have a complete patient profile, there can be 750 critical data elements in a healthcare transaction, as compared to an estimated 150 data elements in a financial transaction. Historical, behavioral, and diagnostic information is needed at multiple points along the continuum of care: physician's office, rehabilitation, pharmacy, emergency room, laboratory, and hospital. Additionally, these points along the continuum must communicate with the community they serve and the purchasers of healthcare. This article looks at data warehousing and the different technologies available for consolidating and integrating information in the healthcare environment.

Increased natural killer cells in fluids. A new, sensitive means of detecting carcinoma

OBJECTIVE

Natural killer (NK) cells are cells of undefined lineage that are capable of lysing certain tumor cell lines in vitro. Determination of NK cell percent (NK%) in effusions by flow cytometry could aid in the detection of malignancies.

STUDY DESIGN

Over a six-month period at the Houston Veterans Affairs Medical Center, fresh effusions were routinely processed for cytology, and a portion was submitted for lymphocyte immunophenotyping using the FACScan and a panel including CD16/CD56 for NK cells. Seventy fluids (42 pleural, 28 peritoneal) from 62 men were examined.

RESULTS

NK cell percents were markedly increased in 15 cases (29-68%, mean 45.5) and low in 55 (2-20%, mean 8). Fourteen of the 15 cases with increased NK% were positive for carcinoma (93%), while 54/55 cases with low ones were negative for carcinoma (98%). Mesotheliomas, lymphomas and leukemias had low NK%.

CONCLUSION

Using the Mann-Whitney U test, an increase in NK% predicts metastatic carcinoma with a P level of < .00001.

Patterns and mechanisms of in-stent restenosis. A serial intravascular ultrasound study

BACKGROUND

Studies have suggested that restenosis within Palmaz-Schatz stents results from neointimal hyperplasia or chronic stent recoil and occurs more frequently at the articulation.

METHODS AND RESULTS

Serial intravascular ultrasound (IVUS) was performed after intervention and at follow-up in 142 stents in 115 lesions. IVUS measurements (external elastic membrane [EEM], stent, and lumen cross-sectional areas [CSAs] and diameters) were performed, and plaque CSA (EEM lumen in reference segments and stent lumen in stented segments), late lumen loss (delta lumen), remodeling (delta EEM in reference segments and delta stent in stented segments), and tissue growth (delta plaque) were calculated. After intervention, the lumen tended to be smallest at the articulation because of tissue prolapse. At follow-up, tissue growth was uniformly distributed throughout the stent; the tendency for greater neointimal tissue accumulation at the central articulation reached statistical significance only when normalized for the smaller postintervention lumen CSA. In stented segments, late lumen area loss correlated strongly with tissue growth but only weakly with remodeling. Stents affected adjacent vessel segments; remodeling progressively increased and tissue growth progressively decreased at distances from the edge of the stent. These findings were similar in native arteries and saphenous vein grafts and in lesions treated with one or two stents. There was no difference in the postintervention or follow-up lumen (at the junction of the two stents) when overlapped were compared with nonoverlapped stents.

CONCLUSIONS

Late lumen loss and in-stent restenosis were the result of neointimal tissue proliferation, which tended to be uniformly distributed over the length of the stent.

Mechanisms and results of balloon angioplasty for the treatment of in-stent restenosis

Restenosis within tubular slotted stents is secondary to intimal hyperplasia and is usually treated with percutaneous transluminal coronary angioplasty (PTCA). Sequential intravascular ultrasound (IVUS) was used to assess the mechanisms and results of PTCA for in-stent restenosis. Sixty-four restenotic Palmaz-Schatz stents were studied by IVUS imaging before and after PTCA. IVUS measurements of stent and lumen cross-sectional areas (CSAs) at 5 segments (proximal and distal stent edges, proximal and distal stent bodies, and the central articulation) were used to calculate intimal hyperplasia CSA (stent-lumen CSA). The results of the 5 segments were then averaged. Mean and minimum CSAs were compared before and after PTCA. Quantitative angiographic measurements showed a minimal lumen diameter increase from 1.05 +/- 0.63 mm (mean +/- 1 SD) before intervention to 2.77 +/- 0.51 mm after PTCA (p < 0.0001). Conversely, the diameter stenosis decreased from 63 +/- 19% to 18 +/- 12% (p < 0.0001). IVUS measurements showed a minimum lumen CSA increase from 2.3 +/- 1.3 mm2 to 6.1 +/- 2.2 mm2 (p < 0.0001) as a result of an increased minimum stent CSA (7.2 +/- 2.4 mm2 to 8.7 +/- 2.6 mm2, p < 0.0001) and a decreased intimal hyperplasia CSA within the stent (4.9 +/- 2.2 mm2 to 2.7 +/- 2.0 mm2, p < 0.0001). Of the total mean lumen enlargement, 56 +/- 28% was the result of additional stent expansion and 44 +/- 28% was the result of a decrease in neointimal tissue. The minimum lumen CSA after PTCA was significantly smaller than the minimum stent CSA before PTCA (presumably an accurate reflection of lumen dimensions immediately after stent implantation; p = 0.0002). The mechanism of PTCA for restenosis is a combination of additional stent expansion and tissue extrusion out of the stent; there is a relatively high residual stenosis (angiographic diameter stenosis of 18 +/- 12%).

Taxol content of Irish yews

The average annual taxol content of shoots with dark green needles from Irish Yew (Taxus baccata var. fastigiata) was found to be 0.0075%. Maximum levels were recorded in April (0.010%) and minimum in February. Golden-leaved ("aurea") varieties contained only traces of taxol. Shoot growth took place mainly between May and July.

Intravascular ultrasound predictors of restenosis after percutaneous transcatheter coronary revascularization

OBJECTIVES

This study sought to evaluate preintervention and postintervention intravascular ultrasound studies for potential predictors of angiographic restenosis and to use ultrasound predictors of restenosis to enhance our understanding of the pathophysiology of the restenosis disease process.

BACKGROUND

Restenosis remains the major limitation of percutaneous transcatheter coronary revascularization. Although its mechanisms remain incompletely understood, numerous studies have identified some of the clinical, anatomic and procedural risk factors for restenosis. Intravascular ultrasound imaging of target lesions before and after catheter-based treatment consistently demonstrates more target lesion calcium, more extensive reference segment atherosclerosis, smaller final lumen dimensions, significant residual plaque burden and a greater degree of tissue trauma than is evident by angiography.

METHODS

Intravascular ultrasound studies were performed in 360 nonstented native coronary artery lesions (final diameter stenosis 18 +/- 11%) in 351 patients for whom follow-up angiographic data were available 6.4 +/- 3.6 months later. Hospital charts were reviewed, and qualitative and quantitative coronary angiographic and intravascular ultrasound analyses were performed by independent core laboratories. Four dependent angiographic end points were tested: restenosis as a binary definition (> or = 50% diameter stenosis at follow-up) was the primary end point; follow-up diameter stenosis, late lumen loss and follow-up minimal lumen diameter were the secondary end points.

RESULTS

Reference vessel size, the preintervention quantitative coronary angiographic assessment of lesion severity and the postintervention intravascular ultrasound cross-sectional measurements predicted the late angiographic results. In particular, the intravascular ultrasound postintervention cross-sectional narrowing (plaque plus media cross-sectional area divided by external elastic membrane cross-sectional area) predicted the primary end point (restenosis) and two of the three secondary end points (follow-up diameter stenosis and late lumen loss) and was therefore the most consistent predictor of restenosis.

CONCLUSIONS

Intravascular ultrasound variables are more powerful and consistent predictors of angiographic restenosis than currently accepted clinical or angiographic risk factors.

Mechanisms and immediate and long-term results of adjunct directional coronary atherectomy after rotational atherectomy

OBJECTIVES

The purpose of this study was to confirm the mechanisms and the immediate and long-term results of rotational atherectomy and adjunct directional coronary atherectomy.

BACKGROUND

Rotational atherectomy is best suited for treating calcific stenoses, but the ability of rotational atherectomy alone to optimize lumen dimensions in large vessels is limited; this is only partly improved by adjunct balloon angioplasty.

METHODS

We treated 165 lesions in 163 patients by use of rotational atherectomy and adjunct directional coronary atherectomy. Quantitative angiography and intravascular ultrasound were used for lesion analysis. A matched comparison with 208 lesions treated with rotational atherectomy and adjunct coronary angioplasty was performed. Patients were then followed up for at least 9 months, and target-lesion revascularization was assessed.

RESULTS

In the 61 lesions imaged sequentially, lumen area increased from 1.7 +/- 0.8 (mean +/- 1 SD) to 3.9 +/- 1.1 mm(2) after rotational atherectomy, owing to a decrease in plaque plus media area from 16.8 +/- 5.0 to 15.2 +/- 5.2 mm(2) (both p < 0.0001). After adjunct directional coronary atherectomy, lumen area increased even more to 6.7 +/- 2.0 mm(2) (vs. 5.1 +/- 1.4 mm(2) after adjunct coronary angioplasty, p < 0.0001) as a result of both vessel expansion (18.8 +/ 5.3 to 20.8 +/- 5.7 mm(2)) and additional plaque removal (to 14.1 +/- 5.0 mm(2), all p < 0.0001). The total arcs of calcium decreased from 207 +/- 107 degrees to 166 +/- 93 degrees after rotational atherectomy and to 145 +/- 87 degrees after directional coronary atherectomy. Overall, procedural success was 96%, and final diameter stenosis was 15 +/- 17%. Target-lesion revascularization was 23%. The only independent predictor of target-lesion revascularization was a larger overall atherectomy index (84% vs. 59%, p = 0.048).

CONCLUSIONS

There is a synergistic relationship between rotational atherectomy and directional coronary atherectomy in the treatment of calcific lesions. The immediate results show a high procedural success--lumen dimensions were larger and late target-lesion revascularization was lower in lesions treated with rotational atherectomy and directional coronary atherectomy than in those treated with rotational atherectomy and adjunct balloon angioplasty.

Intravascular ultrasound findings after excimer laser coronary angioplasty

Intravascular ultrasound (IVUS) was used to study 104 lesions in 98 patients after excimer laser coronary angioplasty (ELCA). Lesion site external elastic membrane (EEM) and lumen cross-sectional areas (CSA) were measured; plaque+media (P+M = EEM - lumen) CSA and percentage of cross-sectional narrowing (CSN = P+M CSA/EEM CSA) were calculated; and the results were compared to a reference site. The lumen CSA (2.6 +/- 1.0 mm2) averaged 24% larger than the cross-sectional area of the largest laser catheter used, and 64 lesions (62%) fit the definition of arterial expansion (lesion EEM CSA > reference site EEM CSA). The residual percentage of cross-sectional narrowing averaged 83.8 +/- 8.8%. Dissections were present in 44% of lesions, and were more common in lesions with superficial calcium (59%) than in lesions with only deep calcium (31%) or no calcium (20%, P = 0.0102). Dissections of superficial calcified plaque had an unusual "shattered" or "fragmented" appearance. These findings suggest that excimer laser angioplasty causes forced vessel expansion with dissection, but limited atheroablation.

Evaluation of HLA antibodies with the PRA-STAT test. An ELISA test using soluble HLA class I molecules

HLA-specific antibody, present before or after transplantation, may adversely effect graft outcome. Antibody testing by cytotoxicity (CYT) is laborious, requires viable lymphocytes, does not differentiate non-HLA cytotoxic antibody, and cannot be used readily on specimens from patients being treated with cytotoxic antibodies. We have evaluated PRA-STAT, an antibody screening kit that uses an ELISA test with soluble HLA class I molecules as targets. We performed 219 tests on a variety of serum specimens, 128 of which were also tested by CYT. There was a highly significant correlation (r = 0.78, P < 0.001) between PRA-STAT (PS) and CYT for the detection of IgG antibodies. Of 66 sera reactive in both assays, 18% had identical specificities defined in both, 27% were more reactive in PS than in CYT, 8% were more reactive in CYT, and 47% had different specificities in the 2 assays, with overlap in slightly more than half the cases. Of 13 sera reactive only in PS, 2 were from non-transfused, nontransplanted males with no evidence of lymphocyte-reactive antibody by antiglobulin tests. PS uses an IgG-specific conjugate, therefore IgM class I-specific antibodies cannot be identified--however, their presence does affect test outcome. This, as well as the panel composition and interlot reproducibility, are areas we believe need to be addressed. The PRA-STAT system is rapid, does not require viable cells or complement, and can be automated in part. Resolution of the problems identified here and availability of an IgM-specific conjugate should make this test system a valuable tool in histocompatibility testing.

A potential role for interferon-alpha in the pathogenesis of HIV-associated dementia

Previous studies in patients receiving interferon-alpha (IFN-alpha) therapy and patients with systemic lupus erythematosus have demonstrated that elevated cerebrospinal fluid (CSF) levels of IFN-alpha are associated with cognitive dysfunction. We measured IFN-alpha levels in CSF and blood by ELISA in human immunodeficiency virus (HIV)-positive patients with (n = 21) and without (n = 23) dementia and HIV-negative controls (n = 48). IFN-alpha was significantly elevated in the CSF of HIV-positive patients with dementia compared to those without dementia and controls. An increasing amount of IFN-alpha in the CSF was correlated with the clinical parameter of increasing Memorial Sloan Kettering scores; although these correlations were not statistically significant, they further suggest an association of increased CSF IFN-alpha with neurocognitive dysfunction in AIDS. Immunocytochemical staining of brains demonstrated IFN-alpha-positive macrophages and astrocytes in frontal cortex and white matter and IFN-alpha mRNA was detected by reverse transcriptase-polymerase chain reaction, further indicating that IFN-alpha is made by cells within the brain and suggesting that the significant increases of IFN-alpha protein found in the CSF of patients with HIV-associated dementia complex are derived from intrinsic brain cells such as macrophages and astrocytes. Increased local production of IFN-alpha during HIV infection may contribute directly or indirectly to the pathogenesis of HIV-associated dementia.