Successful redeployment of an unexpanded coronary stent

We report on treatment of a patient in whom failure to deploy the distal portion of a Palmaz-Schatz stent occurred but was not recognized. After an unstable course, the patient underwent repeat coronary angiography, at which time the stent was rewired and redilated. Full deployment of the stent with restoration of TIMI grade 3 flow was achieved. The putative cause of the problem, incomplete deployment of the stent because of inadvertent advancement of the stent delivery sheath, should be avoided, and needs to be recognized if it occurs. Crossing and redilating the stent is possible, although technically difficult.

Pathobiologic responses to stenting

As the interventions available to treat obstructive coronary artery disease become increasingly complex, our understanding of the vascular response to these interventions requires greater sophistication. Molecular and cellular biologic tools have now propelled us into another phase of work with vascular devices. Initially, studies of endovascular implants such as stents focused on developing models of vascular injury. With these models, we could then examine the designs of individual stents and connect structure with performance. Now we are entering a third phase in which stent manufacturers are looking to science to dictate stent design.

Contracting for clinical genetic services: the Welsh model

In a time of increasing competition for clinical services resources, it is imperative that health professionals actively participate in the commissioning process in order to ensure that established clinical standards are not compromised. Introduction of the NHS reforms in the UK in the early 1990s highlighted the difficulties in contracting for a specialised service such as clinical genetics, especially in the absence of a consensus regarding the contract currency. An average block contract price for each new family referred was introduced in Wales in 1992, and data from the subsequent five years show that this charging system is economically feasible and has the advantages of (1) recognising the contribution to care of non-medical personnel on the genetics team, (2) covering follow up including the counselling of relatives, (3) protecting the service from loss of income owing to non-attendance, and (4) providing a basis for negotiation when new services are being proposed to purchasers. Activity data show that while the majority of conditions incur below average cost, the mean cost is influenced by a small number of autosomal dominant and X linked disorders. The cost risk to the provider for seeing families over an extended period is minimal, as the data establish that family files experience an exponential decrease in activation probability over the early years, but this becomes constant later on. The robustness of the system is dependent on accurate baseline data on referral patterns to the service, recording of activity, and staff costs.

Strategies to maintain the credibility of sham acupuncture used as a control treatment in clinical trials

Many clinical trials concerning acupuncture are flawed by methodological problems. One of the major difficulties is the appropriate selection and use of a placebo control. This article evaluates the use of sham acupuncture as a placebo control and analyzes its credibility as a control treatment. Sixty-four subjects were assessed for their perception of whether they were receiving sham or real acupuncture while participating in a clinical trial of acupuncture. It was found that if used under specific experimental conditions, sham acupuncture can function as a credible control. Specific strategies are suggested to maintain the credibility of sham acupuncture as a placebo control.

Treatment of myopic astigmatism with the Summit Apex Plus excimer laser

PURPOSE

To assess the results of surface sequential toric photorefractive keratectomy (PRK) with the Summit Apex Plus excimer laser using an erodible mask.

METHODS

A prospective study was performed on consecutive eyes having surface sequential toric PRK over a 4 month treatment period. Attempted astigmatism correction varied from 70 to 100%, depending on the power and axis of the cylinder. The myopic correction was adjusted so the combined treatment aim was emmetropia. Refraction, manual keratometry, corneal haze, and visual acuity data from preoperative and follow-up visits over 12 months were divided into various groups based on the preoperative refraction and analyzed.

RESULTS

Fifty-nine eyes from 48 patients had sequential toric PRK. Preoperatively, the mean spherical equivalent at glasses plane (SEGP) was -4.88 diopters (D) +/- 3.20 (SD) and the mean refractive cylinder, 2.02 +/- 1.04 D. The mean attempted cylinder correction was 1.87 D. At 12 months the mean SEGP was -0.02 +/- 0.67 D, which was not statistically significant from plano. The mean refractive cylinder was 0.84 +/- 0.84 D, which was statistically significantly different from zero cylinder power. There was a statistically significant correlation between the preoperative and the 12 month postoperative refractive cylinder powers. At 12 months, 34 of 43 eyes (79.1%) had an uncorrected visual acuity of 6/12 or better. While 2 eyes in one patient (4.7%) lost two lines of best corrected visual acuity, with a final acuity of 6/12 in each, no patient lost more than two lines.

CONCLUSION

The manifest refraction cylinder power is not fully corrected with the current treatment algorithms; however, surface sequential toric PRK using an erodible mask is capable of treating compound myopic astigmatism with moderate success.

Structural protein 4.1 is located in mammalian centrosomes

Structural protein 4.1 was first characterized as an important 80-kDa protein in the mature red cell membrane skeleton. It is now known to be a member of a family of protein isoforms detected at diverse intracellular sites in many nucleated mammalian cells. We recently reported that protein 4.1 isoforms are present at interphase in nuclear matrix and are rearranged during the cell cycle. Here we report that protein 4.1 epitopes are present in centrosomes of human and murine cells and are detected by using affinity-purified antibodies specific for 80-kDa red cell 4.1 and for 4.1 peptides. Immunofluorescence, by both conventional and confocal microscopy, showed that protein 4.1 epitopes localized in the pericentriolar region. Protein 4.1 epitopes remained in centrosomes after extraction of cells with detergent, salt, and DNase. Higher resolution electron microscopy of detergent-extracted cell whole mounts showed centrosomal protein 4.1 epitopes distributed along centriolar cylinders and on pericentriolar fibers, at least some of which constitute the filamentous network surrounding each centriole. Double-label electron microscopy showed that protein 4.1 epitopes were predominately localized in regions also occupied by epitopes for centrosome-specific autoimmune serum 5051 but were not found on microtubules. Our results suggest that protein 4.1 is an integral component of centrosome structure, in which it may play an important role in centrosome function during cell division and organization of cellular architecture.

Intraocular Lens Power Calculation for Cataract Surgery after Photorefractive Keratectomy for High Myopia

OBJECTIVE

To assess intraocular lens (IOL) power calculations in patients undergoing cataract surgery after excimer laser photorefractive keratectomy (PRK) for myopia.

METHODS

Four eyes of two patients underwent phacoemulsification with IOL implantation after PRK for myopia. The estimated refractive error that would have been induced had the IOL predicted for emmetropia been implanted was calculated using SRK-II, SRK/T, Holladay, and Binkhorst formulas. Manual keratometry and videokeratography-simulated keratometry values measured before surgery were used. Keratometry values calculated by subtracting the refractive change induced by the excimer laser PRK from the manual keratometry or videokeratography-simulated keratometry values measured before PRK were also used. Both spectacle and corneal plane calculations were performed.

RESULTS

Manual keratometry and videokeratography-simulated keratometry values underpredicted the IOL power. Corneal plane manual or videokeratography refraction-derived keratometry calculations were most accurate using the SRK/T formula, while spectacle plane calculations were most accurate using the SRK-II formula. In both methods the calculated refractive error was within 0.52 diopters (D) for the emmetropic lens power predicted. Statistical analysis was not performed.

CONCLUSIONS

Refraction-derived keratometric values provided the most accuracy in calculating IOL powers. Our results suggest the SRK/T formula was the most accurate for corneal plane calculations, while the SRK-II formula was the most accurate for spectacle plane calculations.

Excimer Laser Photorefractive Keratectomy for Hyperopia

OBJECTIVE

To prospectively study excimer laser correction of hyperopia, with a 1-year followup.

METHODS

Eleven consecutive hyperopic eyes (10 phakic and 1 aphakic) underwent correction of hyperopia using the Summit Technology SVS Apex Plus excimer laser. Data collection included cycloplegic refraction, spectacle-corrected visual acuity, contrast sensitivity, corneal haze, manual keratometry, and videokeratography. Prior to treatment the mean hyperopic spherical equivalent refraction (corneal plane) was +5.80 diopters (D) (SD2.10). The mean attempted correction was +3.09 D at the corneal plane.

RESULTS

Refractive data for the group showed a mean overcorrection at 1 month of +3.18 D. This regressed slightly before stabilizing at 3 months, with a mean overcorrection of +1.88 D. Thereafter there was no statistically significant fluctuation in refraction (p = 0.67). The amount of overcorrection and regression was greater in eyes that received higher corrections. Changes in manual keratometry and videokeratography mirrored the attempted correction more closely than refraction, although stabilization did not occur until 6 months.

CONCLUSIONS

Because the hyperopic correction achieved when measured by refraction was greater than expected, algorithms should be adjusted. The hyperopic erodible disc and Axicon lens system is capable of treating low to moderate amounts of hyperopia.

Bacterial typing: storing and processing of stabilized reference bacteria for polymerase chain reaction without preparing DNA--an example of an automatable procedure

This paper examines the use of bacteria killed on blood-storage paper as templates (ghosts) and takes, as an example, the PCR ribotyping (amplification of the intergenic spacer regions between the 16S and 23S ribosomal RNA genes) of bacteria as described by Kostman et al. (J. Infect. Dis. 171, 204-208, 1995). All procedures have been particularly designed to be compatible with automation. DNA preparation is inappropriate for routine, high-volume sequence amplification from a diversity of microorganism cultures. Blood-storage/processing media provide another way of processing samples for PCR with distinctive aspects of increased safety and ease of automatibility. Blood-storage paper can be used for killing and processing bacteria to DNA-containing ghosts for reliable PCR. From as little as a few microliters of an overnight culture or a reasonably sized, single colony, rapid processing of large sample numbers is possible. FTA blood-storage medium has additional utility in that long-term cataloguing, storage, and processing of paper, loaded with culture, for PCR, is possible via a variety of sample wash sequences. It can be performed at convenience, after collection, and can be delayed indefinitely. using this approach, the repeatability of some PCR-ribotyping methodology of the type used by Kostman et al. (J. Clin. Microbiol. 30, 2084-2087, 1992) was examined as an exercise to demonstrate the practicality of FTA blood-paper usage and to check some basic features of PCR ribotyping. Five strains of Staphylococcus and one strain Escherichia coli were stored and processed on FTA blood paper, the PCR-ribotype patterns were analyzed and found to be the equal of patterns previously seen via additional DNA preparations.

The General Practice Morbidity Database Project Wales--a methodology for primary care data extraction

There is a fundamental need for accurate, timely and relevant information for health service planning; the increasing focus on a primary care led NHS has made the collection of information from general practitioners a priority. A collaborative project between general practitioners and public health physicians in Wales has developed methodologies for the extraction and analysis of routinely collected data from general practices across Wales. Four commonly used computer systems have been investigated. This paper outlines the methodologies used and describes the problems encountered and their solutions.

7E3 monoclonal antibody directed against the platelet glycoprotein IIb/IIIa cross-reacts with the leukocyte integrin Mac-1 and blocks adhesion to fibrinogen and ICAM-1

Recent clinical trials suggest that blockade of integrins is a promising strategy for the treatment of acute coronary syndromes. Administration of 7E3 monoclonal antibody (mAb) Fab fragment (c7E3 Fab) directed against platelet integrin IIb/IIIa (alpha IIb beta 3, CD41/CD61) reduces acute ischemic complications of coronary angioplasty and clinical restenosis at 6 months. However, 7E3 mAb is not selective for platelet IIb/IIIa but also cross-reacts with the leukocyte integrin Mac-1 (alpha M beta 2, CD11b/CD18) and the vitronectin receptor (alpha v beta 3, CD51/CD61). Information regarding how this mAb may affect other cells important in vascular repair is scant. Potential interactions of c7E3 Fab with inflammatory (i.e., monocytes and neutrophils), vascular smooth muscle, and endothelial cells may contribute to the in vivo actions of c7E3 Fab. In this study we explored the binding of 7E3 to monocytic cells and the functional effect of 7E3 and c7E3 Fab on Mac-1-mediated adhesion to fibrinogen (FGN) and intercellular adhesion molecule-1 (ICAM-1), ligands abundant in the injured vessel wall. Flow cytometry demonstrated that 7E3 bound to THP-1 monocytic cells and identified a subpopulation (approximately 10%) of Mac-1 that was qualitatively similar to that recognized by CBRM1/5, a mAb directed to an activation-specific neoepitope present on a subset of Mac-1 molecules. mAb 7E3 bound to K562 cells transfected with just the alpha subunit (CD11b) of Mac-1 but not to nontransfected cells, confirming a direct interaction between 7E3 and Mac-1. mAb 7E3 and c7E3 Fab blocked the adhesion of Mac-1-bearing cells to FGN (80 +/- 11% and 78 +/- 9% inhibition, respectively) and ICAM-1 (62 +/- 14% and 62 +/- 17%). Both 7E3 and c7E3 Fab significantly inhibited (70 +/- 6% and 62 +/- 26%) soluble FGN binding to human peripheral blood monocytes. Thus, c7E3 Fab cross-reacts with the CD11b subunit of Mac-1 and interrupts cell-extracellular matrix and cell-cell adhesive interactions and may thereby influence the recruitment of circulating monocytes to sites of vessel injury. Given the recent evidence that adherent and infiltrating monocyte number directly correlates with the extent of neointimal hyperplasia, inhibition of Mac-1-dependent adhesion and IIb/IIIa-dependent function by c7E3 Fab may jointly contribute to the regulation of vascular repair and to the sustained clinical benefits observed with c7E3 Fab after angioplasty.

Performance characteristics of the Gen-Probe Probe Competition Assay used as a supplementary test for the Gen-Probe PACE 2 and 2C assays for detection of Chlamydia trachomatis

The performance characteristics of the Gen-Probe Probe Competition Assay (PCA) used in conjunction with the Gen-Probe PACE 2 and 2C direct detection assays for Chlamydia trachomatis were examined. Data collected by five public health laboratories by using the Gen-Probe PACE 2 were pooled and analyzed. Of 25,081 endocervical and male urethral specimens tested by the PACE 2 assay, 773 were tested by PCA. Of 334 specimens initially positive by the PACE 2 assay with an initial PACE 2 result of greater than 2,000 relative light units (RLU), 333 (99.7%) were positive by PCA while 242 of 339 (71.4%) specimens with an initial result between the cutoff and 2,000 RLU were positive by PCA, and 35 of 100 (35%) specimens with initial results between 200 RLU and the cutoff were positive by PCA. An additional 10,938 specimens were tested by the PACE 2C assay. Of these, positive PCA results were obtained for 187 of 188 (99.5%) specimens with initial results of greater than 2,000 RLU, 99 of 163 (60.7%) of specimens in the range of cutoff to 2,000 RLU, and 12 of 100 (12%) in the range of 200 RLU to the cutoff. These results indicate that specimens greater than 2,000 RLU do not require a supplemental test and that additional positive results can be obtained by testing specimens with an initial result below the cutoff.

Endogenous cell seeding. Remnant endothelium after stenting enhances vascular repair

BACKGROUND

Endothelial integrity is essential for maintaining vascular homeostasis, and endothelial denudation results in neointimal thickening. Balloon-expandable endovascular stents provide a luminal scaffolding within atherosclerotic arteries with minimal direct contact between balloon and endothelium. We wondered whether stents cause diminished endothelial ablation, and if so, whether the degree of endothelial damage might determine later proliferative sequelae.

METHODS AND RESULTS

Stainless steel stents were expanded in normal or previously denuded iliac arteries of New Zealand White rabbits. Stented arteries were harvested 15 minutes, 1 hour, 3 days, or 14 days later. En face staining of the luminal surfaces of stented arteries demonstrated that endothelial cell loss began immediately after stent expansion and was restricted to interstices between stent struts. Remnant endothelium adjacent to struts provided the foundation for complete endothelial regeneration of the stented segment within 3 days. Both early monocyte adhesion and later intimal macrophage accumulation were reduced > 80% in nonballooned but stented arteries, in concert with a twofold reduction in intimal thickening after 14 days, compared with arteries completely denuded with a balloon before stent expansion.

CONCLUSIONS

It is accepted that deep injury caused by balloon-expanded endovascular stents is a critical contributor to experimental stent-induced neointimal hyperplasia. Our data indicate that the degree of endothelial injury may also be an important component of vascular repair after stenting and an important consideration in stent and balloon design and use. The use of stents for primary endovascular intervention may allow partial retention of endothelium within treated arteries, thereby modulating vascular repair with less need for adjunctive pharmacological therapy.

Monocyte recruitment and neointimal hyperplasia in rabbits. Coupled inhibitory effects of heparin

Among the many effects of heparin independent of its effects on coagulation are inhibition of vascular smooth muscle cell proliferation and regulation of leukocyte-blood vessel interactions. The potential link between these effects was examined in an animal model of vascular injury rich in inflammatory cells: the placement of endovascular metal stents in rabbit iliac arteries. Monocyte adhesion stimulated by early focal thrombus was maximal after 3 days, with infiltrating monocytes and intimal cell proliferation maximal after 7 days. Tissue monocyte number dictated cell proliferation at each time point (R2 = .92, P < .0001). Heparin reduced both early monocyte adhesion as well as monocyte infiltration within the neointima 7 and 14 days after stent placement. Reductions in adherent and tissue monocytes were commensurate with reductions in intimal cell proliferation and intimal thickening. At 14 days, heparin's inhibition of mononuclear cell adhesion was correlated with its suppression of intimal thickening (R2 = .82, P < .0001). Monocytes have been hypothesized to serve as markers, initiators, and promoters of arterial occlusive diseases. Heparin's ability to inhibit mononuclear cell adhesion and penetration and reduce neointimal size and cell proliferation after vascular injury may further implicate monocytes in the pathogenesis of neointimal hyperplasia after mechanical arterial injury.

Multiple excimer laser retreatments for scarring and myopic regression following photorefractive keratectomy

Excimer laser retreatment for scarring with myopic regression following photorefractive keratectomy (PRK) has been reported. We present the 38 month course of a patient who had PRK followed by two retreatments. The patient experienced scarring with myopic regression after an initial PRK with a 5.00 mm ablation zone. These complications recurred 13 months after retreatment with a 5.00 mm ablation zone. Refractive effect, computer-assisted videokeratography measurements, and corneal clarity remained stable 12 months after a second retreatment with a 6.00 mm ablation zone, indicating that retreatment with a larger ablation zone diameter appeared to be an appropriate method for handling this complication.

Expression of the alpha(1,3)fucosyltransferase Fuc-TVII in lymphoid aggregate high endothelial venules correlates with expression of L-selectin ligands

Lymphocyte homing to lymph nodes and Peyer's patches is mediated, in part, by adhesive interactions between L-selectin expressed by lymphocytes and L-selectin ligands displayed at the surface of the cuboidal endothelial cells lining the post-capillary venules within lymphoid aggregates. Candidate terminal oligosaccharide structures thought to be essential for effective L-selectin ligand activity include a sulfated derivative of the sialyl Lewis x tetrasaccharide. Cell type-specific synthesis of this oligosaccharide is presumed to require one or more alpha(1,3)fucosyltransferases, operating upon common 3'-sialylated and/or sulfated N-acetyllactosamine-type precursors. The identity of the alpha(1,3)fucosyltransferase(s) expressed in cells that bear L-selectin ligands has not been defined. We report here the molecular cloning and characterization of a murine alpha(1,3)fucosyltransferase locus whose expression pattern correlates with expression of high affinity ligands for L-selectin. In situ hybridization and immunohistochemical analyses demonstrate that this cDNA and its cognate alpha(1,3)fucosyltransferase are expressed in endothelial cells lining the high endothelial venules of peripheral lymph nodes, mesenteric lymph nodes, and Peyer's patches. These expression patterns correlate precisely with the expression pattern of L-selectin ligands identified with a chimeric L-selectin/IgM immunohistochemical probe and by the high endothelial venule-reactive monoclonal antibody MECA-79. Transcripts corresponding to this cDNA are also detected in isolated bone marrow cells, a source rich in the surface-localized ligands for E- and P-selectins. Sequence and functional analyses indicate that this murine enzyme corresponds to the human Fuc-TVII locus. These observations suggest that Fuc-TVII participates in the generation of alpha(1,3)fucosylated ligands for L-selectin and provide further evidence for a role for this enzyme in E- and P-selectin ligand expression in leukocytes.

Lidocaine inhibits blood coagulation: implications for epidural blood patch

Lidocaine in the epidural space, through inhibitory effects upon coagulation, may contribute to inefficacy of epidural autologous blood patch (EBP). This study was undertaken to evaluate the effect of achievable epidural concentrations of lidocaine on blood coagulation as a step in testing this hypothesis. Ex vivo blood coagulation using whole blood (n = 20) was studied with computerized thrombelastography (TEG). Each blood specimen was exposed to serial dilutions of lidocaine hydrochloride or saline to form end-concentrations of 0.0 mM, 2.3 mM, 4.6 mM, 9.2 mM, 18.5 mM, and 36.9 mM lidocaine. Statistical analysis using analysis of variance for repeated measures revealed that the three highest lidocaine concentrations tested caused hypocoagulable and/or fibrinolytic changes as compared with controls. Achievable epidural admixtures of lidocaine and whole blood will impair coagulation. Therefore, residual lidocaine in the epidural space may contribute to failures of immediate or early EBP.

Early versus late prenatal care in New Mexico: barriers and motivators

BACKGROUND

Adequate prenatal care is important for ensuring a good outcome for pregnant women and their children, and its initiation in the first trimester is a major component. We investigated barriers and motivators for women receiving early versus late prenatal care.

METHODS

A self-administered questionnaire was distributed to 205 women who began prenatal care at the University of New Mexico Hospital Obstetrics Clinic in Albuquerque, New Mexico. The questionnaire assessed demographic information, insurance status, feelings about the pregnancy, health behaviors, and barriers and motivators to initiating prenatal care. The participants were Hispanic (41%) and non-Hispanic white (46%), low-income women with Medicaid (42%) or no health insurance (41%). They were divided into early (1st trimester 67%) and late (after 1st trimester 33%) care groups.

RESULTS

Ethnicity, education, income, and age did not predict initiation of prenatal care. Late initiators cited financial problems (26%), not being aware of the pregnancy (15%), and dislike of going to doctors (14%) as reasons for the delay in seeking prenatal care. Over two-thirds of the pregnancies were unplanned, but 82 percent of the women felt positive about the pregnancy.

CONCLUSIONS

Our study documents the continuing need for public health efforts to encourage women to seek early prenatal care. Specific attention should be directed toward women's perceived reasons for not initiating early care.