Effect of pattern topology on the self-cleaning properties of textured surfaces

The water contact angle and self-cleaning property of microfabricated surface textures possessing different topologies are compared. In one kind of surface textures, the protruded regions form a connected square network. In the other kind of surface textures, the protruded regions form a regular array of square posts. We find that the water apparent contact angle of the connected textures agrees with the Cassie equation [Discuss. Faraday Soc. 3, 11 (1948)], but that of the disconnected textures is much larger. Nevertheless, the disconnected textures exhibit inferior self-cleaning property, contrary to conventional conception. We discuss the possible reasons for these observations.

Relative potential for selection of quinolone-resistance-determining-region mutations in Streptococcus pneumoniae by gemifloxacin, gatifloxacin and moxifloxacin

Serial passage of a clinical isolate of Streptococcus pneumoniae, in the presence of moxifloxacin, gatifloxacin or gemifloxacin, gave rise to resistant isolates. Non-susceptibility as defined by Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS) breakpoints arose on Days 10, 11, and 12 with gatifloxacin, gemifloxacin, and moxifloxacin respectively. Moxifloxacin and gatifloxacin selected for a single step quinolone-resistant-determining-region (QRDR) mutation in DNA gyrase (GyrA) on Day 4 and 7 respectively, whereas gemifloxacin selected simultaneously for multi-step mutations in gyrase and topoisomerase IV (ParC) on Day 17 and activated a non-reserpine inhibited efflux mechanism by Day 4. As found in clinical isolates, mutations included Ser-81-Phe and Glu-85-Lys in GyrA and Ser-79-Phe or Asp-83-Tyr in ParC. At high MICs, moxifloxacin showed a previously unreported 4 amino-acid deletion in GyrB as well as a more unusual substitution Ser-79-Leu/Ile in ParC. Gemifloxacin showed a 2- to 16-fold greater activity than moxifloxacin or gatifloxacin against strains with two or more QRDR mutations, however, its potency did not translate to nonsusceptibility and gemifloxacin MIC values were either at or well above the CLSI nonsusceptible breakpoint concentration.

Procaspase-3 enhances the in vitro effect of cytosine deaminase-thymidine kinase disuicide gene therapy on human ovarian cancer

Because the efficacy of genetic prodrug activation therapy (GPAT) using herpes simplex virus thymidine kinase (tk)/ganciclovir (GCV) or Escherichia coli cytosine deaminase (cd)/5-fluorocytosine (5-FC) is not satisfied in early clinical trials and the mechanism of both the GPATs have been shown to lead to the activation of cell apoptotic pathway, we hypothesized that coexpression of procaspase-3, a central downstream executioner of apoptotic pathways, with cd-tk gene leads to enhanced cell death in ovarian cancer cells in vitro. Following transfection with the vectors encoding cd and tk, 5-FC and GCV treatments lead to greater cell death in procaspase-3-expressing clones of 3AO (3AO-caspase-3) than control cells (3AO-pcDNA3), as well as more rapid activation of caspase-3 and more rapid cleavage of poly (adenosine diphosphate-ribose) polymerase (PARP). There is a greater degree of cell apoptotic rate in the procaspase-3-expressing clones than in control cells following the treatment with cd-tk/5-FC + GCV, and apoptosis is the main cell death form. None of these effects is seen following transfection with a control vector that does not encode tk and cd (pBTdel-279). The results strongly suggest that coexpression of procaspase-3 may lead to a significant enhancement of the efficacy of cd-tk/5-FC + GCV, and this strategy would be a novel and promising approach for the treatment of ovarian cancer.

Arsenic trioxide induces apoptosis in cisplatin-sensitive and -resistant ovarian cancer cell lines

Arsenic trioxide (As(2)O(3)), has been used for centuries in traditional Chinese medicine; it has considerable efficacy in the treatment of relapsed acute promyelocytic leukemia, inducing partial differentiation and promoting apoptosis of malignant promyelocytes. Although a number of studies have demonstrated that As(2)O(3) has potent activity against cell growth in a series of leukemia cell lines, little information is available regarding this compound's effect on cell growth in solid tumor cell lines. In this study, we investigated the effects of As(2)O(3)in vitro on ovarian cancer cell lines sensitive (3AO) and resistant (3AO/CDDP) to cisplatin. The 3-(4,5-dimethy-thiazoyl-2-yl)-2,5-diphenyl-tetrazolium bromide assay was used to evaluate cytotoxicity. Flow cytometric analysis was used to determine the apoptosis, cell cycle distribution. We clearly demonstrated that As(2)O(3) induced cell apoptosis and inhibition of cell growth in both the cell lines. Furthermore, we identified that As(2)O(3)-induced apoptosis involved Fas pathway. As(2)O(3) is an active agent against ovarian cancer cells and could be effective in the clinical treatment of ovarian cancer.

Ultrastructure alterations in adriamycin-resistant and cisplatin-resistant human ovarian cancer cell lines exposed to nonlethal ultrasound

Human ovarian cancer cell lines, SKOV3 and its adriamycin-resistant substrain SKOV3/ADR and COC1 and its cisplatin-resistant substrain COC1/DDP, were exposed to nonlethal ultrasound. Ultrastructures in sham-insonated and insonated cells were inspected by transmission electron microscopy, and cytochrome C in cytosol was determined by enzyme-linked immunosorbent assay. Ultrasound exposure led to no significant changes in SKOV3/ADR cells, but tumid mitochondria occurred in SKOV3 cells. Mitochondria changes were also detected in some exposed COC1 and COC1/DDP cells. Apoptotic bodies could be detected in either control or insonated COC1/DDP cells. A few exposed COC1/DDP cells became reticular. Cytochrome C in cytosol in exposed SKOV3/ADR cells was increased but that in exposed COC1/DDP cells was decreased. These findings revealed that the bioeffect of ultrasound on chemosensitive cells was not identical to that of chemoresistant ones, and ultrasound was a potential approach for treatment of drug-resistant ovarian cancers.

Ultrastructure alterations in adriamycin-resistant and cisplatin-resistant human ovarian cancer cell lines exposed to nonlethal ultrasound

Human ovarian cancer cell lines, SKOV3 and its adriamycin-resistant substrain SKOV3/ADR and COC1 and its cisplatin-resistant substrain COC1/DDP, were exposed to nonlethal ultrasound. Ultrastructures in sham-insonated and insonated cells were inspected by transmission electron microscopy, and cytochrome C in cytosol was determined by enzyme-linked immunosorbent assay. Ultrasound exposure led to no significant changes in SKOV3/ADR cells, but tumid mitochondria occurred in SKOV3 cells. Mitochondria changes were also detected in some exposed COC1 and COC1/DDP cells. Apoptotic bodies could be detected in either control or insonated COC1/DDP cells. A few exposed COC1/DDP cells became reticular. Cytochrome C in cytosol in exposed SKOV3/ADR cells was increased but that in exposed COC1/DDP cells was decreased. These findings revealed that the bioeffect of ultrasound on chemosensitive cells was not identical to that of chemoresistant ones, and ultrasound was a potential approach for treatment of drug-resistant ovarian cancers.

[Cloning and sequencing of 16S rRNA gene of Phytoplasma CWB1 strain associated with cactus witches' broom]

A 1.5 kb DNA fragment was amplified in DNA samples extracted from Opuntia salmiana porm showed witches'-broom symptom. The result indicates the existence of phytoplasma associated with this disease and this phytoplasma was designated as CWB1. The amplified fragment was ligated to pGEM-T easy vector and then transformed into JM109 strain of E. coli. Cloned DNA fragments were verified by PCR, restriction endonuclease (EcoRI) digestion and sequence analysis. The result revealed that the 16S rRNA gene of CWB1 consists of 1489 bp and shared 99.7% homology with Faba bean phyllody which belongs to phytoplasma 16S rII-C subgroup. So we can classify this strain into phytoplasma 16S rII-C subgroup.

Insulin secretion and sensitivity during oral glucose tolerance test in Korean lean elderly women

Impaired glucose tolerance (IGT) and type 2 diabetes including undiagnosed isolated postchallenge hyperglycemia (IPH) are common in the elderly. The aim of this study was to investigate the insulin secretion and sensitivity in Korean elderly lean diabetic women. Forty-one lean women aged 65-88 years took 2 hr oral glucose tolerance test (OGTT) and were stratified according to the WHO criteria (normal glucose tolerance [NGT], n=20; IGT, n=6; and type 2 diabetics, n=15 including seven IPH). HbA1c and fructosamine progressively increased from the NGT to the diabetic subjects (p=0.006 and p=0.001, respectively). Compared with subjects with NGT, the insulinogenic index, a marker of early insulin secretion and the AUC(ins), a marker of total insulin secretion, decreased significantly in diabetic group [0.53 (-0.44 -1.45) vs. 0.18 (0.00 -1.11), p=0.03 and 306+/-165 vs. 199+/-78 pmol/L, p=0.02 respectively]. A significant difference was found in the AUC(c-peptide) among each group (221+/-59 vs. 206+/-34 vs. 149+/-51 pmol/L, p=0.001 for each). The homeostasis model assessment of insulin resistance (HOMA-IR), a marker of insulin resistance, was not different among the groups. We conclude that compared with NGT subjects, elderly lean women with diabetes have impaired oral glucose-induced insulin secretion but have relatively preserved insulin sensitivity. This suggests that insulin resistance is not necessarily an essential component of Korean elderly lean diabetic women.

[Targeted killing effect of mucin-1 single chain antibody targeting, lentivirus-mediated suicide gene therapy and ganciclovir in mucin-1+ ovarian epithelial carcinoma cells]

OBJECTIVE

To investigate the targeted killing effect of mucin-1 single chain antibody targeting, lentivirus-mediated suicide gene therapy and ganciclovir(GCV) in mucin-1+ ovarian epithelial carcinoma cells.

METHODS

Mucin-1 single chain antibody targeting lentivirus produced by packaging cell line 293T transduced herpes simplex virus thymidine kinase (HSV-tk) gene into the ovarian epithelial cancer cell line SKOV3 (MUC1+). The infection effect was observed through fluorescence microscopy. Polymerase chain reaction (PCR) and reverse transcription-PCR (RT-PCR) were resorted to demonstrate the successful transduction and transcription of the HSV-tk gene. After administration of GCV, changes of those cells were observed through optical microscopy. The cytotoxicity efficacy of HSV-tk/GCV system was evaluated by methyl thiazolyl tetrazolium method.

RESULTS

It was observed through fluorescence microscopy that anti-MUC1 directed lentivirus can specificly infect MUC1+ ovarian cancer cells. A fragment of 600 bp was generated through PCR and RT-PCR which indicated successful transduction and transcription of the HSV-tk gene in SKOV3 cells. Changes of cells followed by administration of GCV were observed with optical microscopy. Significant cytotoxicity efficacy of GCV to SKOV3 was observed.

CONCLUSIONS

The HSV-tk gene can be targetedly transducted into MUC1+ ovarian cancer cell line under the mediation of anti-MUC1 directed lentivirus, and such HSV-tk/GCV system has targetingly killing effect on MUC1+ cancer cells.

[Gene transfer of CD80 into a human ovarian cancer cell line and induction of cytotoxic T lymphocyte in vitro]

OBJECTIVE

To investigate the proliferation and cytotoxicity of cytotoxic T lymphocyte (CTL) induced by ovarian cancer cells transfected with a CD80 gene containing retroviral vector.

METHODS

The ovarian cancer cell line TYK cells were transfected with retro-virus vector PLXSN-hCD80. After geneticin (G418) selection, the CD80 expression of the transfectants was confirmed by flow cytometry. CTL was induced by co-culture of CD80-expressing TYK cells (TYK-hCD80) and peripheral-blood mononuclear cells (PBMC) in the presence of anti-CD3 monoclonal antibody (McAb). Proliferation of PBMC was measured using 3H-Thymidine incorporation assay. The lysis activity of CTL toward tumor cells was determined using methyl thiazolyl tetrazolium (MTT) assay.

RESULTS

After transfection and G418 selection, the CD80 expression was proved by flow cytometry. The highest rate of CD80 expression was 84.9%. The TYK cell line expressing high CD80 was named TYK-hCD80. In the presence of anti-CD3 McAb, TYK-hCD80 significantly enhanced proliferation of PBMC than TYK cells (3H-Thymidine incorporation, (40,604 +/- 842) vs (8,000 +/- 594) cpm (P < 0.05). The lysis activity of CTL activated by TYK-hCD80 was higher than that of TYK(P < 0.05).

CONCLUSIONS

Ovarian cancer cells expressing CD80 can induce the production of CTLs which have high lysis activity and high proliferation rate in the presence of anti-CD3 McAb. This study may provide the experimental basis for immunogenic therapy of ovarian cancer.

VP22 enhanced intercellular trafficking of HSV thymidine kinase reduced the level of ganciclovir needed to cause suicide cell death

BACKGROUND

The inefficiency of herpes simplex virus thymidine kinase (TK) gene transfer and toxicity of ganciclovir (GCV) at high concentrations in vivo limits the use of this suicide gene therapy approach for the treatment of cancers in clinical settings. To overcome the problem, we have sought evidence of amplification of cytotoxicity by co-transfer of the TK gene fused with the gene encoding HSV-1 structural protein VP22 which has a remarkable ability for intercellular trafficking.

METHODS

The expression of the fusion proteins from the chimeric VP22-TK or VP22-EGFP genes was shown by Western blot and VP22 promoted TK or EGFP intercellular trafficking by an indirect immunofluorescent assay. The cytotoxicity was demonstrated by a colorimetric cell proliferation assay followed by an assessment of the bystander effect on admixtures of transfected with non-transfected naive cells.

RESULTS

Our results show the expression of the VP22 fusion proteins and their spread to varying numbers of bystander cells (up to 30, observed in viable cells with VP22-EGFP as well as after methanol fixation), confirming that VP22 assisted intercellular trafficking of the fusion proteins. This VP22 promoted TK spreading resulted in killing by 2.5 microg/ml GCV of virtually all cells in cultures that had been transfected at an efficiency of only 27.5%. In contrast, fewer than 80% of cells were killed when transfected with 'tk alone' at the same efficiency. The cell killing effect was exponentially dependent on GCV concentration in cells transfected with 'tk alone' at GCV concentrations between 0.25 and 0.5 microg/ml, but not those transfected with VP22-TK, probably due to the continuously variable, high sensitivity of about 50% of cells. Even at low concentration of GCV (0.2 microg/ml), the enhancement of cell killing by VP22 was four-fold higher in cells transfected with VP22-TK than in cells transfected with 'tk alone'.

CONCLUSIONS

VP22 enhanced intercellular trafficking of TK and amplified the TK/GCV killing effect, especially in the lower range of GCV concentrations. This offers a new strategy to enhance the effectiveness of suicide gene therapy for the treatment of cancers.

[Adenovirus-mediated herpes simplex virus thymidine kinase gene transference and combined drug therapy leads to apoptosis of human epithelial ovarian cancer cells]

OBJECTIVE

To evaluate the treatment and apoptosis effect of adenovirus-mediated herpes simplex virus thymidine kinase (HSV1-tk) gene transference followed by administration of ganciclovir (GCV) and acyclovir (ACV) on ovarian epithelial cancer cells.

METHODS

Recombinant adenovirus was amplificated and purified by routine method. The expression of HSV1-tk gene was assayed by polymerase chain reaction (PCR). The efficiency of recombinant Advtk transference was evaluated. The cytotoxicity efficacy of TYK cells that carry HSV1-tk gene was evaluated followed by GCV, ACV administration after the transference of Advtk. The changes and apoptosis of TYK cells that carry HSV1-tk gene were observed by means of analysis of DNA fragmentation and electronic microscopy.

RESULTS

Adenovirus was amplificated and purified in large amount. PCR assay showed 404 bp special band. When the multiplicities of infection (MOI) was 100, the transduction rate was 98.9%. The inhibition rates of TYK cells that carry HSV1-tk gene increased with the increase of MOI when the same concentration of GCV, ACV were given. When the MOI was same, the inhibition rates were also increased with the increase concentration of GCV, ACV. Apoptosis of TYK cells that carry HSV1-tk gene after administration of GCV was observed by means of analysis of DNA fragmentation and electronic microscopy.

CONCLUSIONS

The HSV1-tk gene can effectively transferred into TYK cells by recombinant replicated-deficient adenovirus vector, GCV, ACV can effectively kill TYK cells that carry HSV1-tk gene in vitro. Apoptosis may be the mechanism of the killing effect.

Role of phosphate and kinetic characteristics of complete iron release from native pig spleen ferritin-Fe

The kinetics for complete iron release showing biphasic behavior from pig spleen ferritin-Fe (PSFF) was measured by spectrophotometry. The native core within the PSFF shell consisted of 1682 hydroxide Fe3+ and 13 phosphate molecules. Inhibition kinetics for complete iron release was measure by differential spectrophotometry in the presence of phosphate; the process was clearly divided into two phases involving a first-order reaction at an increasing rate of 46.5 Fe3+/PSFF/min on the surface of the iron core and a zero-order reaction at a decreasing rate of 6.67 Fe3+/PSFF/min inside the core. The kinetic equation [C(PSFF-Fe3+)max - C(PSFF-Fe3+)t](1/2) = Tmax - Tt gives the transition time between the two rates and represents the complex kinetic characteristics. The rate was directly accelerated twofold by a mixed reducer of dithionite and ascorbic acid. These results suggest that the channel of the PSFF shell may carry out multiple functions for iron metabolism and storage and that the phosphate strongly affects the rate of iron release.

[Study of the inhibitory effects of retrovirus-mediated p16 gene on human ovarian cancer cell line]

OBJECTIVE

To study the inhibitory effects of retro-virus-mediated p16 gene on human ovarian cancer cell line CAOV3.

METHODS

Recombinant eukaryotic expression vector pDOR-p16 containing exogenous human wt-p16 cDNA and vector with neomycin resistance gene only were introduced by lipofectamine-mediated gene transfection into CAOV3 cell line which does not express p16 endogenously. By using revert-polymerase chain reaction amplification, mRNA in situ hybridization and immunocytochemistry, the clones obtained were detected for their efficiency of transfection and effects of vector expression and observed for their biologic behavior.

RESULTS

Exogenous wt-p16 had successfully been transferred into CAVO3 cells and obtained permanent expression. The growth rate of these transfected CAOV3 cells in regular medium and soft agar was inhibited, and the tumorigenicity in nude mice showed that two in four mice failed to form tumor and the others suffered from tumor later than contrast group by 7 to 14 days. The percentage of phase G1 cells increased and that of phase S cells decreased by analysing cell cycle. The ultrastructural changes of the cells were observed under electron microscope, revealing necrosis and growth retardation.

CONCLUSIONS

p16 gene played an important role in generation and development of ovarian carcinoma. This study might provide the experimental evidence for the gene therapy in human ovarian cancer.

The aortic homograft: evolution of indications, techniques, and results in 107 patients

BACKGROUND

Homograft aortic valve replacement has been performed in 107 patients during the past 7 years. Two primary methods of implantation were used (intraaortic and root replacement). Results of both methods are presented.

METHODS

Intraaortic implantation (subcoronary or cylinder technique) was performed in 36 patients (mean age, 54 years) for aortic stenosis or regurgitation (31 patients) and endocarditis (5 patients). Aortic root replacement was performed in 71 patients (mean age, 62 years). The majority (58 patients) had complex root pathologies such as ascending aneurysm, dissection, or prosthetic endocarditis with annular destruction. Early results were assessed with intraoperative or predischarge echocardiography; annual echocardiograms provided long-term follow-up. Left ventricular mass was calculated in patients with long-standing pathology for whom preoperative and postoperative data were available.

RESULTS

Early valvular insufficiency was documented in 16 of the 36 intraaortic implants (44%); 9 of these have had progression of the insufficiency. Of the 20 patients who had trivial or no early insufficiency, significant insufficiency has developed in 7 and mild insufficiency has developed in 5. Calculation of left ventricular mass revealed a mean reduction of 11% at 1 year. There has been no mortality, endocarditis, or homograft-related reoperation in the intraaortic group with a mean follow-up of 50 months. The root replacement group had a hospital mortality of 17%. The cardiac pathology was limited to the aortic valve in 12 patients; mortality in this subset was zero. There has been no significant early or late postoperative valvular insufficiency in the 59 surviving patients. More rapid left ventricular mass reduction was seen in this group with a 26% mean reduction within 1 year. A mean follow-up of 32 months in the root replacement group has seen no homograft-related reoperations.

CONCLUSIONS

Although the lack of early mortality in the intraaortic group makes this technique appealing, the high incidence of early insufficiency with the realistic expectation of progression has led to our abandonment of the intraaortic technique. Homograft aortic root replacement confers a higher mortality based on the severity of aortic pathology, but offers excellent long-term hemodynamics in any patient. We have expanded our indication for homograft root replacement to include patients with isolated valvular disease rather than reserving it for those patients with extensive root pathology.

IL-6 antisense-mediated growth inhibition of a choriocarcinoma cell line: an intracellular autocrine growth mechanism

The growth of tumor cells can be regulated by a variety of cytokines. To investigate the pathogenesis of choriocarcinoma and explore a new therapeutic approach for the carcinoma, we examined the role of IL-6 in the growth of a human choriocarcinoma cell line (JEG-3). IL-6 was identified in the supernatant of the cell culture medium by enzyme-linked immunosorbent assay, indicating that this cell secreted IL-6. The mRNAs of IL-6, IL-6 receptor and gP130, the IL-6 signal transducer, in this cell were shown to be present by reverse transcriptase polymerase chain reaction assay and confirmed by Southern blot hybridization and direct sequencing. The addition of hrIL-6 to the cell culture failed to stimulate cell growth. Monoclonal antibodies against IL-6, IL-6 receptor, and gP130 were also unable to inhibit the proliferation of this cell line. The antisense oligonucleotides targeting IL-6 mRNA, however, inhibited both cell growth and IL-6 production. Taken together, these findings indicate that endogenous IL-6 plays an important role in the growth of the JEG-3 cell line, and it exerts its action by an intracellular autocrine growth mechanism. The results also suggest that the therapeutic trials with monoclonal antibodies designed to neutralize IL-6 or block its receptor will likely fail, whereas the antisense oligonucleotides targeted to IL-6 mRNA may have some value for the treatment of choriocarcinoma and other cancers with intracellular autocrine growth fashion mediated by IL-6.

Synthesis and bronchodilatory activity of four new derivatives of deoxyvasicine

As part of a continuing effort aimed at the development of efficacious antihistaminic and bronchodilator agents for the treatment of asthma and related respiratory diseases, a series of novel trisubstituted deoxyvasicine derivatives was designed and synthesized. Bronchodilatory activity of pure samples of ligands 17a-d, and DL-8-chlorovasicine hydrochloride is investigated and compared with isoprenaline and aminophylline. These studies confirm the activity of ligands 17a-d and the potentiating effect of 17c on aminophylline.

Arachidonic acid release: an in vitro alternative for dermal irritancy testing

Validated in vitro alternatives are being utilized extensively for mutagenicity and ocular irritancy testing. However, validation of alternative assays for dermal irritancy is progressing more slowly. As the irritant response in human skin is mediated, at least in part, by eicosanoids derived from arachidonic acid, the effect of relatively pure anionic surfactants (AS, n=8) and surfactant-containing finished products (FP, n=25) on the release of [3H]arachidonic acid from a prelabelled murine fibroblast cell line (C3H-10T1/2 cells) in vitro was examined. Test substances were administered at various non-lethal concentrations, in triplicate, to 12- and 24-well plates containing preconfluent monolayers (80-90% confluence) of C3H-10T1/2 cells. Because it is impossible to test all concentrations of each test substance in a single assay, statistical techniques were developed to 'standardize' in vitro assay results. In each assay, radiolabel release due to a positive control was also measured, using 0.04, 0.05 and 0.06 mM concentrations of sodium dodecyl sulfate (SDS). Test substance releases were then transformed into 'SDS equivalent' responses, significantly reducing both inter- and intra-assay variability. A straight line was fitted to the test substance responses and compared with that for SDS to calculate the relative potency in vitro for individual AS and FP. Relative potencies correlated with in vivo responses, that is primary dermal irritation indices obtained in rabbits, with Spearman p=0.408 (P<0.03) for 32 tested agents, and p=0.976 (P<0.001) for the eight AS. Exclusion of extremely alkaline or acidic FP (pH>11 or <2, n=4) and those which were insoluble in the aqueous cell culture media at the 1% stock dilution (n=5), improved the overall in vivo-in vitro correlation significantly (p=0.683, P<0.001, n=23) and produced a significant correlation for FP alone (p=0.539, P<0.05, n=15). These results suggest that release of [3H]arachidonic acid from cultured skin cells represents a novel, mechanistically based in vitro screen for dermal irritancy testing.

Early experience with homograft aortic root replacement for complex aortic pathology

BACKGROUND

Complex aortic valve and root pathology presents a serious operative challenge.

METHODS

During the last 45 months 21 cryopreserved homograft root replacements have been performed in 19 patients. The ages of the patients ranged from 28 to 77 years; there were 15 men and four women. Six patients had endocarditis, four prosthetic and two native valve endocarditis. One patient underwent homograft aortic root replacement twice; one underwent concomitant homograft right ventricular outflow tract reconstruction for pulmonic endocarditis. Causes of aortic pathology in the other 13 patients included ascending aortic aneurysm with valvular regurgitation in seven, Marfan syndrome in two, and four aortic dissections with aortic regurgitation. Ten of the nineteen patients were undergoing reoperative procedures.

RESULTS

There were three hospital deaths and one death at home of unknown cause. Two of the three patients who died in hospital had undergone redo cardiac procedures. Dramatic functional class improvement was seen in all survivors.

CONCLUSIONS

Follow-up from 2 to 45 months in the fifteen survivors revealed no clinical or significant echocardiographic evidence of valvular regurgitation or recurrent infection. We believe homograft root replacement provides an excellent method of reconstruction with several advantages unique to human valved conduits, including ease of handling, lack of synthetic nidus for recurrent infection, and absence of thrombogenic materials. Homografts should be considered the approach of choice in complex valvular and root infectious processes.

Prognostic value of dipyridamole thallium-201 scintigraphy in patients with stable chest pain

The usefulness of dipyridamole testing with planar thallium-201 scintigraphy for assessing risk of subsequent cardiac events was evaluated in 373 patients with stable chest pain. Follow-up information was complete in 362 patients (mean age 64 +/- 9 years). During an average follow-up period of 18 months, cardiac events occurred in 59 patients--unstable angina in 27, nonfatal acute myocardial infarction in 11, and death from cardiac causes in 21. A history of previous myocardial infarction, congestive heart failure, or coronary bypass surgery before the study, or the presence of an abnormal scan or one with a fixed perfusion defect was associated with a significantly increased frequency of subsequent cardiac events (p less than 0.05). However, the presence of a reversible perfusion defect was not associated with increased risk (p = 0.1872). Stepwise logistic regression showed that a history of coronary artery bypass surgery before the study and the presence of a fixed perfusion defect were the only variables with independent predictive value for occurrence of a subsequent cardiac event (p less than 0.05). Survival analysis revealed a significantly increased cardiac event rate in patients with abnormal scans compared with those with normal scans over a 30-month follow-up period (p less than 0.01). We conclude that dipyridamole testing with thallium-201 scintigraphy can provide prognostic information concerning risk of future cardiac events in patients with stable chest pain. The presence of a fixed perfusion defect in particular identifies patients at increased risk.

Effect of exercise level on the ability of thallium-201 tomographic imaging in detecting coronary artery disease: analysis of 461 patients

This study examined the effect of the level of exercise on the ability of thallium-201 imaging with single photon emission computed tomography (SPECT) to detect coronary artery disease. Patients in group 1 (n = 164) achieved adequate exercise end points, defined as positive exercise electrocardiograms or greater than or equal to 85% of maximal predicted heart rate. Patients in group 2 (n = 108) had submaximal exercise. The SPECT thallium-201 images showed perfusion defects in 74%, 88%, and 98%, respectively, of patients with one, two and three vessel coronary artery disease in group 1, compared with 52%, 84% and 79%, respectively, of such patients in group 2 (p less than 0.05). Perfusion defects showed partial or complete redistribution consistent with ischemia in 56%, 80% and 88%, respectively, of patients with one, two and three vessel coronary artery disease in group 1 compared with 35%, 58% and 56%, respectively, of such patients in group 2 (p = 0.08, less than 0.03 and less than 0.001, respectively). Of 58 patients with normal coronary angiograms or less than 50% diameter stenosis, 36 (62%) had normal SPECT images. In a separate group of 131 patients with less than 5% pretest probability of coronary artery disease, the specificity was 93%. The sensitivity of exercise SPECT imaging in group 1 was higher than that of ST segment depression (p less than 0.001). Thus, the level of exercise affects the results of SPECT thallium imaging in the localization and evaluation of the extent of coronary artery disease and the detection of ischemia.

Use of oral dipyridamole SPECT thallium-201 imaging in detection of coronary artery disease

This study examined the merits of oral dipyridamole SPECT thallium-201 imaging in detecting CAD and multivessel CAD. The 65 patients included in this study (aged 62 +/- 11 years) were not candidates for exercise testing (for the usual reasons). Coronary arteriography revealed no significant CAD in 17 patients and greater than or equal to 50% narrowing of one or more vessels in 48 patients; 12 had one-vessel and 36 had multivessel CAD (high-risk group). Thallium-201 was injected intravenously 45 minutes after an oral dose of 375 mg of dipyridamole, and SPECT imaging was performed within 10 minutes and 4 hours after injection. There were no serious side effects; only six patients (8%) had ST segment depression and 18 patients (28%) had chest pain. The heart rate increased from 74 +/- 15 beats/min at rest to 84 +/- 14 beats/min at peak effect (p = 0.001); the systolic blood pressure did not change (130 +/- 18 and 128 +/- 20 mm Hg, respectively, p = NS). The thallium images were abnormal in 6 of 17 patients (35%) with no CAD, in 7 of 12 patients with one-vessel disease (58%), and in 34 of 36 patients with multivessel CAD (94%) (p = 0.001). Twenty-one of 25 patients (84%) with a perfusion abnormality in more than one vascular territory had multivessel CAD assessed by angiography. Thus oral dipyridamole SPECT thallium-201 imaging is a safe and inexpensive method for the detection of CAD in patients who are otherwise not candidates for exercise testing.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of technetium-99m isonitrile (RP-30A) in assessing left ventricular perfusion and function at rest and during exercise in coronary artery disease, and comparison with coronary arteriography and exercise thallium-201 SPECT imaging

This study compared the results of stress and rest single-photon emission computed tomography imaging of myocardial perfusion using technetium-99m isonitrile (RP-30A) with the results of stress and redistribution tomographic thallium imaging and the results of coronary arteriography in 39 patients, 11 without and 28 with coronary artery disease (CAD). Each patient underwent 2 exercise studies at identical workload, heart rate and double product. In a subset of 13 patients, concomitant evaluation of left ventricular (LV) function using first-pass radionuclide angiography with a multi-crystal camera also was performed with bolus injections of isonitrile. Isonitrile had similar sensitivity (82 vs 82%, difference not significant), a slightly--but not significantly--higher specificity (100 vs 82%) and similar predictive accuracy (87 vs 82%) to thallium-201. The tracer uptake was assessed in 20 segments/study. There was concordance between the isonitrile and thallium-201 images in 723 of the 780 segments (93%) (kappa = 0.83 +/- 0.02). In general, the isonitrile images were considered of better quality than the thallium-201 images. All 10 patients with CAD who underwent concomitant first-pass radionuclide angiography had either perfusion abnormalities or an abnormal ejection fraction response to exercise. Thus, technetium-99m isonitrile provides a reliable method of assessment of CAD with a sensitivity, specificity and predictive accuracy comparable to that of exercise thallium-201 imaging. Additional advantages include better image quality and the ability to obtain concomitant assessment of LV function with the use of first-pass radionuclide angiography.

Elimination of amphotericin B in impaired renal function

The influence of impaired renal function on the steady-state plasma clearance of amphotericin B was determined in seven patients with creatinine clearances ranging from zero to normal. Contrary to previous reports, steady-state plasma concentrations of total drug were lower in uremic patients than in patients with normal renal function. Total plasma clearance of amphotericin B ranged from 16.7 to 39.9 ml/min, correlated directly with the plasma creatinine concentration, and correlated inversely with the creatinine clearance. Urinary excretion of unchanged drug accounted for less than 10% of the dose. In 10 healthy subjects, mean percent of amphotericin B unbound in plasma was 3.55 +/- 0.32 (SD). Binding was determined in a further group of 10 uremic patients. Mean unbound percent (4.15 +/- 0.73, SD) was higher than in the healthy subjects, and the binding ratio (molar concentration of bound to unbound drug) correlated weakly with the creatinine clearance. This suggests that plasma clearance of unbound amphotericin B and, therefore, steady-state plasma concentrations of unbound drug are not affected by renal impairment, and that dosage requirements will be overestimated if based on measurements of total drug plasma concentration.