Direct coronary stenting without predilatation: a new therapeutic approach with a special balloon catheter design

Coronary stenting is the primary therapeutic option for many coronary lesions, after the risk of subacute stent thrombosis and bleeding complications has been reduced by antithrombotic regimens and improved stent expansion. It would be desirable to shorten the procedure and the duration of ischemia, and to reduce the risk of ischemic complications during balloon inflation by implanting the stent without previous dilatation of the lesion. This is not possible with the presently available stent delivery systems. This new therapeutic concept was tested with a specially designed balloon catheter, on which slotted-tube stents can be fixed between two conical radiopaque markers. Sixty-one patients eligible for angioplasty underwent direct stent implantation without predilatation. Four procedures were performed for acute myocardial infarction, and two as high-risk PTCA. Single slotted-tube stents (Palmaz-Schatz, NIR, or JOStent) of 14-16-mm length were mounted between the conical radiopaque markers of a special balloon which provided a fixation for the crimped stent. The direct implantation was successful in 80% of all patients, while in 10% the stent could be deployed after predilatation of the lesion. In 10% of lesions a stent could not be implanted with this and any other delivery system. When patients with successful direct stenting were compared with those with indirect (after predilatation) or unsuccessful stent deployment, the presence of angiographically visible calcification was higher in the unsuccessful cases (75% vs. 19%; P < 0.01), and the patients were older (72+/-8 vs. 61+/-12 years; P < 0.01). Radiation exposure time was only 8.7+/-5.1 min as compared with 12.6+/-7.6 min in conventional stent procedures with predilatation (P < 0.05). The number of balloons used per lesion was also lower than with conventional stenting. Stent dislocation was observed in 5%, and no embolization occurred. The new therapeutic approach of direct stenting without predilatation proved to be a safe and successful procedure in this initial series of coronary angioplasties. When calcified coronary lesions are avoided, it provides a way to rationalize stent implantation with shorter radiation exposure times, fewer balloons, and the potential advantage of fewer ischemic complications as no balloon predilatation is required.     

Effect of oral acyclovir or ganciclovir therapy after preemptive intravenous ganciclovir therapy to prevent cytomegalovirus disease in cytomegalovirus seropositive renal and liver transplant recipients receiving antilymphocyte antibody therapy

BACKGROUND: Organ transplant recipients who are seropositive for cytomegalovirus (CMV) and who are treated with antilymphocyte antibody (ALA) therapy have a high rate of symptomatic CMV disease. The intravenous administration of ganciclovir therapy once daily during ALA therapy decreased the incidence from 24% to 10% in patients receiving ALA as an induction therapy and from 64% to 22% in those treated for rejection. The present study was undertaken to determine whether a more intensive and sustained antiviral regimen could be more effective. METHODS: From April 1995 to December 1997, all CMV seropositive renal and liver transplant recipients who received ALA therapy were treated with intravenously administered ganciclovir (5 mg/kg/day with dose adjusted for renal dysfunction) for the length of ALA therapy and then with orally administered acyclovir (400 mg three times/day) or ganciclovir (1 gm twice/day) for 3 to 4 months. The incidence of CMV viremia and of CMV disease was determined during the 6 months after completion of ALA therapy. RESULTS: Forty-one patients (35 renal and 6 liver transplant recipients) were studied. CMV disease occurred in 2 patients (4.9%), both of whom were treated for rejection; it occurred in 1 of 21 patients (4.8%) treated with orally administered acyclovir, and in 1 of 20 patients (5%) treated with orally administered ganciclovir. The only patient who developed CMV disease in the ganciclovir group had received only 26 days of oral antiviral therapy. No CMV disease was documented in the group of patients receiving ALA therapy as induction therapy. CMV viremia occurred in three patients in the acyclovir group (14.3%) and in one patient in the ganciclovir group (5%). Among renal transplant recipients only, 1 of 35 patients developed CMV disease (2.9%) and no case of CMV disease was documented in patients treated with orally administered ganciclovir. All six patients receiving two courses of ALA therapy each were free of CMV disease. Toxicity of the regimen was minimal, and antiviral resistance did not develop. CONCLUSIONS: Preemptive antiviral therapy with intravenously administered ganciclovir during ALA therapy and then orally administered ganciclovir for 3 to 4 months provides virtually complete protection against the excessive rate of CMV disease that occurs in CMV seropositive allograft recipients receiving ALA therapy.     

Bacteria for the nineties

Staphylococcus aureus and Enterococci have gained prominence as the causes of wound infections during this decade. Methicillin-resistant Staphylococcus aureus (MRSA) became commonplace in the United States during the 1980s. In Canada, infections with MRSA have been increasing in frequency since 1995. MRSA develops resistance by producing an altered penicillin-binding protein, PBP 2a, coded for by the mecA gene. Vancomycin is the usual drug of choice. Recently, strains with intermediate resistance to vancomycin (VISA) have been isolated from patients in Japan and the United States. Interim guidelines for their control have been developed by the Centers for Disease Control. Enterococci have developed a resistance to a variety of antimicrobials during the past three decades, including beta-lactams and aminoglycosides. Recently, strains resistant to vancomycin (VRE) have been found in the United States and Canada. They are particularly difficult to treat, although some success has been achieved with experimental drugs. These microorganisms have the ability to escape control by antimicrobials almost as soon as they are developed. Thus, we must practice good infection control and reserve antimicrobials only for clear cases of infection if we are to prevent or delay the emergence of resistance.     

Compliance with primary prevention in private practice: creating a tobacco-free environment

A sample of private orthodontic practices (n = 40) from a controlled trial for clinician-initiated tobacco-use prevention was used to test the effectiveness of preventive medicine representative (PMR) visits in creating and maintaining an anti-tobacco office environment. Clinical staff of 20 offices, randomly assigned to the experimental group, were trained by a PMR on the use of anti-tobacco materials (no-smoking signs, posters, and print materials). Twenty control-group offices did not receive any training or special treatment. Subsequently, experimental-group offices were visited by a PMR once every three months and were telephoned six weeks after each visit over a 12-month period. During visits and phone calls, PMRs prompted offices to order anti-tobacco materials. Visits served to introduce offices to new materials and to encourage their continued use. Data from direct observations and self-report measures showed significant differences between experimental and control offices for display of anti-tobacco materials at 1.5 months and 12 months (P < .001). Results suggest that PMR visits may serve as an effective method of introducing and maintaining preventive medicine procedures in clinical environments.     

Mammalian mitochondrial ribosomal proteins. N-terminal amino acid sequencing, characterization, and identification of corresponding gene sequences

The integrity of healthy mitochondria is supposed to depend largely on proper mitochondrial protein biosynthesis. Mitochondrial ribosomal proteins (MRPs) are directly involved in this process. To identify mammalian mitochondrial ribosomal proteins and their corresponding genes, we purified mature rat MRPs and determined 12 different N-terminal amino acid sequences. Using this peptide information, data banks were screened for corresponding DNA sequences to identify the genes or to establish consensus cDNAs and to characterize the deduced MRP open reading frames. Eight different groups of corresponding mammalian MRPs constituted from human, mouse, and rat origin were identified. Five of them show significant sequence similarities to bacterial and/or yeast mitochondrial ribosomal proteins. However, MRPs are much less conserved in respect to the amino acid sequence among species than cytoplasmic ribosomal proteins of eukaryotes and bacteria.     

Haemonchus contortus glycoproteins contain N-linked oligosaccharides with novel highly fucosylated core structures

Structural studies on the N-linked oligosaccharides of Haemonchus contortus, an economically important nematode that parasitizes domestic ruminants, have revealed core fucosylation of a type not previously observed in any eukaryotic glycoprotein. Mass spectrometric analyses were performed on detergent extracts of homogenized adult H. contortus and on purified H11, a glycoprotein isolated from intestinal brush borders which has been previously shown to be an effective vaccine antigen. The major N-linked glycans identified in the present study have up to three fucose residues attached to their chitobiose cores. The fucoses are found at the 3- and/or 6-positions of the proximal GlcNAc and at the 3-position of the distal GlcNAc. The latter substitution is unique in N-glycans. Most anti-H11 monoclonal antibodies are known to recognize carbohydrate epitopes, and it is possible that the newly discovered multifucosylated core structures are highly immunogenic in this glycoprotein.     

Perceptions of tonal changes in normal laryngeal, esophageal, and artificial laryngeal male Cantonese speakers

PURPOSE: Present radiobiological studies for different cell lines in vitro demonstrate the equivalence and efficacy of continuous low-dose-rate brachytherapy (LDR-BT) and pulsed dose rate brachytherapy (PDR-BT) when using small and frequent dose pulses. The aim of this study was to examine monolayer fibroblast cultures in vitro to examine the biological effects of different pulse doses and dose rates under clinically conditions. MATERIAL AND METHODS: B14 cells, Hy B14 FAF 28, peritoneal fibroblasts, were cultured in multi-well plates and exposed to a PDR radiation source at a distance of 9 mm. The following PDR-schemes were compared: dose per pulse: 1 Gy, 2.5 Gy and 5 Gy to a total dose of 5 Gy/5 h (overall time), 10 Gy/10 h, 20 Gy/20 h and 30 Gy/30 h. The pulse duration for the examination of dose rate effects was 20 min, 30 min or 52 min corresponding by dye pulse dose rate of 300 cGy/h, 200 cGy/h or 115 cGy/h. Treatment endpoints were cell measured by dye exclusion test and clonogenic cell survival. RESULTS: Cell survival decreased for pulse doses of 5 Gy compared to 2.5 Gy or 1 Gy per pulse (mean dose rate 200 to 300 cGy/h). No differences were observed with dose rates during irradiation of 300 cGy/h, 200 cGy/h or 115 cGy/h (20 Gy/1 Gy). CONCLUSION: Radiobiological effects of PDR-RT are dependent on the dose per pulse, with differences in biological effects only with a dose per pulse of more than 2.5 Gy, considering the described in-vitro conditions. More examinations with a more pronounced difference in dose rate will be continued for evaluation of dose rate effects.