Tacticity Characterization of Biosynthesized Polyhydroxyalkanoates Containing (S)- and (R)-3-Hydroxy-2-Methylpropionate Units

Polyhydroxyalkanoates (PHAs), aliphatic polyesters synthesized by microorganisms, have gained considerable attention as biodegradable plastics. Recently, α-carbon-methylated PHAs have been shown to exhibit several interesting properties that differ from those of conventional PHAs, such as their crystallization behavior and material properties. This study investigated α-carbon methylated (S)- and (R)-3-hydroxy-2-methylpropionate (3H2MP) as new repeating units. 3H2MP units were homopolymerized or copolymerized with (R)-3-hydroxybutyrate (3HB) by manipulating the culture conditions of recombinant Escherichia coli LSBJ. Consequently, PHAs with 3H2MP units ranging from 5 to 100 mol % were synthesized by external addition of (R)- and (S)-enantiomers or the racemic form of 3H2MPNa. The (S)-3H2MP precursor supplemented into the culture medium was almost directly polymerized into PHA while maintaining its chirality. Therefore, a highly isotactic P(3H2MP) (R:S = 1:99) was synthesized, which displayed a melting temperature of 114-119 °C and a relatively high enthalpy of fusion (68 J/g). In contrast, in cultures supplemented with (R)-3H2MP, the precursor was racemized and polymerized into PHA, resulting in the synthesis of the amorphous polymer atactic P(3H2MP) (R:S = 40:60). However, racemization was not observed at a low concentration of the (R)-3H2MP precursor, thereby synthesizing P(3HB-co-8 mol % 3H2MP) with 100% (R)-3H2MP units. The thermogravimetric analysis revealed that the thermal degradation temperatures at 5% weight loss of P(3H2MP)s occurred at approximately 313 °C, independent of tacticity, which is substantially higher than that of P(3HB) (257 °C). This study demonstrates a new concept for controlling the physical properties of biosynthesized PHA by manipulating the polymers' tacticity using 3H2MP units.

Isolation and characterization of polyhydroxyalkanoate-degrading bacteria in seawater at two different depths from Suruga Bay

IMPORTANCE

Polyhydroxyalkanoate (PHA) is a highly biodegradable microbial polyester, even in marine environments. In this study, we incorporated an enrichment culture-like approach in the process of isolating marine PHA-degrading bacteria. The resulting 91 isolates were suggested to fall into five genera (Alloalcanivorax, Alteromonas, Arenicella, Microbacterium, and Pseudoalteromonas) based on 16S rRNA analysis, including two novel genera (Arenicella and Microbacterium) as marine PHA-degrading bacteria. Microbacterium schleiferi (DSM 20489) and Alteromonas macleodii (NBRC 102226), the type strains closest to the several isolates, have an extracellular poly(3-hydroxybutyrate) [P(3HB)] depolymerase homolog that does not fit a marine-type domain composition. However, A. macleodii exhibited no PHA degradation ability, unlike M. schleiferi. This result demonstrates that the isolated Alteromonas spp. are different species from A. macleodii. P(3HB) depolymerase homologs in the genus Alteromonas should be scrutinized in the future, particularly about which ones work as the depolymerase.

Development of a Hypersensitivity Evaluation Method for Cultured Sensory Neurons Using Electrical Activity Recording

Investigation of hypersensitivity caused by peripheral sensitization progression is important for developing novel pain treatments. Existing methods cannot record plastic changes in neuronal activity because they occur over a few days. We aimed to establish an efficient method to evaluate neuronal activity alterations caused by peripheral sensitization on high-density microelectrode arrays (HD-MEAs) which can record neuronal activity for a long time. Rat dorsal root ganglion (DRG) neurons were dissected from rat embryos and cultured on HD-MEAs. DRG neurons were labeled with NeuO, live staining dye. Neurons were detected with the fluorescence signal and electrodes were selected with the fluorescence images. The number of DRG neurons, whose activity were recorded, detected based on fluorescence observation was five times greater than that based on neuronal activity. Analysis of changes in neuronal activity observed in pharmacological stimulation experiments suggested that substance P induced peripheral sensitization and enhanced capsaicin sensitivity. In addition, results of immunofluorescence staining suggested that peripheral sensitization occurred mostly in neurons that co-expressed transient receptor potential vanilloid 1 (TRPV1) and neurokinin 1 receptor (NK1R). In conclusion, we established an efficient method for assessing the effects of peripheral sensitization on DRG neurons cultured on HD-MEAs.

Exploring Class I polyhydroxyalkanoate synthases with broad substrate specificity for polymerization of structurally diverse monomer units

Polyhydroxyalkanoate (PHA) synthases (PhaCs) are key enzymes in PHA polymerization. PhaCs with broad substrate specificity are attractive for synthesizing structurally diverse PHAs. In the PHA family, 3-hydroxybutyrate (3HB)-based copolymers are industrially produced using Class I PhaCs and can be used as practical biodegradable thermoplastics. However, Class I PhaCs with broad substrate specificities are scarce, prompting our search for novel PhaCs. In this study, four new PhaCs from the bacteria Ferrimonas marina, Plesiomonas shigelloides, Shewanella pealeana, and Vibrio metschnikovii were selected via a homology search against the GenBank database, using the amino acid sequence of Aeromonas caviae PHA synthase (PhaC_Ac), a Class I enzyme with a wide range of substrate specificities, as a template. The four PhaCs were characterized in terms of their polymerization ability and substrate specificity, using Escherichia coli as a host for PHA production. All the new PhaCs were able to synthesize P(3HB) in E. coli with a high molecular weight, surpassing PhaC_Ac. The substrate specificity of PhaCs was evaluated by synthesizing 3HB-based copolymers with 3-hydroxyhexanoate, 3-hydroxy-4-methylvalerate, 3-hydroxy-2-methylbutyrate, and 3-hydroxypivalate monomers. Interestingly, PhaC from P. shigelloides (PhaC_Ps) exhibited relatively broad substrate specificity. PhaC_Ps was further engineered through site-directed mutagenesis, and the variant resulted in an enzyme with improved polymerization ability and substrate specificity.

Continuous Supply of Non-Combustible Gas Mixture for Safe Autotrophic Culture to Produce Polyhydroxyalkanoate by Hydrogen-Oxidizing Bacteria

Polyhydroxyalkanoates (PHAs) are eco-friendly plastics that are thermoplastic and biodegradable in nature. The hydrogen-oxidizing bacterium Ralstonia eutropha can biosynthesize poly[(R)-3-hydroxybutyrate] [P(3HB)], the most common PHA, from carbon dioxide using hydrogen and oxygen as energy sources. In conventional autotrophic cultivation using R. eutropha, a gas mixture containing 75−80 vol% hydrogen is supplied; however, a gas mixture with such a high hydrogen content has a risk of explosion due to gas leakage. In this study, we aimed to develop an efficient cell culture system with a continuous supply of a non-combustible gas mixture (H2: O2: CO2: N2 = 3.8: 7.3: 13.0: 75.9) for safe autotrophic culture to produce P(3HB) by hydrogen-oxidizing bacteria, with a controlled hydrogen concentration under a lower explosive limit concentration. When the gas mixture was continuously supplied to the jar fermentor, the cell growth of R. eutropha H16 significantly improved compared to that in previous studies using flask cultures. Furthermore, an increased gas flow rate and agitation speed enhanced both cell growth and P(3HB) production. Nitrogen source deficiency promoted P(3HB) production, achieving up to 2.94 g/L P(3HB) and 89 wt% P(3HB) content in the cells after 144 h cultivation. R. eutropha NCIMB 11599, recombinant R. eutropha PHB-4, and Azohydromonas lata grew in a low-hydrogen-content gas mixture. R. eutropha H16 and recombinant R. eutropha PHB-4 expressing PHA synthase from Bacillus cereus YB-4 synthesized P(3HB) with a high weight-average molecular weight of 13.5−16.9 × 105. Thus, this autotrophic culture system is highly beneficial for PHA production from carbon dioxide using hydrogen-oxidizing bacteria as the risk of explosion is eliminated.

Risk and benefit trade-off of thromboprophylaxis in patients with Fontan circulation: insights from the National Database of Health Insurance Claims of Japan

Background

Patients with Fontan circulation are at an increased risk of developing thromboembolic events in the first 3–12 months after surgery [1,2]. Thromboembolic events can lead to significant mortality [3]. The current guidelines recommend the use of antithrombotic therapy, either aspirin or warfarin, as a primary thromboprophylaxis [4,5]. On the other hand, the main adverse effect of thromboprophylaxis is bleeding, which may increase the risk of death. However, there are limited data to assess the outcomes of the thromboembolic and bleeding complications of thromboprophylaxis. Therefore, this retrospective cohort study aimed to evaluate the safety and efficacy of thromboprophylaxis after Fontan surgery.

Methods

We identified 1903 patients who underwent Fontan surgery between June 2011 and September 2019 from the National Database of Health Insurance Claims and Specific Health Checkups of Japan. The patients were followed-up from 2 months to 1 year after Fontan surgery to assess the primary outcomes of thromboembolic and bleeding events. Moreover, we identified the factors associated with primary outcomes in this population using multivariate logistic regression analysis.

Results

A total of 1903 patients (56.1% male) underwent Fontan surgery at a median age of 3 years (1–22); 1815 patients (95.4%) had an extracardiac conduit. No thromboprophylaxis was prescribed to 65 patients (3.4%), whereas 228 patients (12.0%) received aspirin alone, 346 patients (18.2%) received warfarin alone, and 1264 patients (66.4%) received a combination therapy of aspirin and warfarin. In the first post-operative year, thromboembolic events occurred in 234 patients (12.3%) and bleeding events occurred in 202 patients (10.6%). Older age (odds ratio, 1.08; 95% confidence interval, 1.06–1.11) and aspirin use (odds ratio, 0.34; 95% confidence interval, 0.15–0.78) were independently associated with thromboembolic events. In particular, up to 5 months after surgery, the incidence rate of thromboembolism was significantly lower in patients who received aspirin alone (0.9%) than in those who received other thromboprophylaxis regimens (no thromboprophylaxis, 13.8%; warfarin, 7.5%; combination therapy, 7.4%; p<0.05). No significant difference in incidence of bleeding events was observed among the four thromboprophylaxis regimens. A history of postoperative hemorrhage (odds ratio, 1.49; 95% confidence interval, 1.01–2.21) and the use of a potassium channel blocker (odds ratio, 2.12; 95% confidence interval, 1.10–4.05) was associated with a higher risk of bleeding events.

Conclusions

In this study, patients who received aspirin alone showed a significantly lower incidence of thromboembolic events. Aspirin may be useful for preventing thromboembolism a year after Fontan surgery. After Fontan surgery, it is important to select a safe and effective thromboprophylaxis regimen and evaluate the risk factors for thromboembolic and bleeding events in a timely manner.

Funding Acknowledgement

Type of funding sources: None.

Characterization of an (R)-specific enoyl-CoA hydratase from Streptomyces sp. strain CFMR 7: A metabolic tool for enhancing the production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] [P(3HB-co-3HHx)] has a high potential to serve as a commercial bioplastic due to its biodegradability, thermoplastic and mechanical properties. The properties of this copolymer are greatly affected by the composition of 3HHx monomer. One of the most efficient ways to modulate the composition of 3HHx monomer in P(3HB-co-3HHx) is by manipulating the (R)-3HHx-CoA monomer supply. In this study, a new (R)-specific enoyl-CoA hydratase originating from a non-PHA producer, Streptomyces sp. strain CFMR 7 (PhaJ_Ss), was characterized and found to be effective in supplying 3HHx monomer during in vivo production of P(3HB-co-3HHx) copolymer. The P(3HB-co-3HHx) copolymer produced from the Cupriavidus necator transformant that harbors phaJ_Ss, PHB^-4/pBBR1-C_BP-M-CPF4J_Ss, showed enhanced 3HHx incorporation of up to 11 mol% without affecting the P(3HB-co-3HHx) production when palm oil was used as the carbon source. In addition, both k_cat and k_cat/K_m of PhaJ_Ss were higher toward the C6 than the shorter C4 substrates, underscoring the preference for 3-hydroxyhexanoyl-CoA. These results suggest that PhaJ_Ss has a significant ability to supply 3HHx monomers for PHA biosynthesis via β-oxidation and can be applied for metabolic engineering of robust PHA-producing strains.

Poly(3-mercapto-2-methylpropionate), a Novel α-Methylated Bio-Polythioester with Rubber-like Elasticity, and Its Copolymer with 3-hydroxybutyrate: Biosynthesis and Characterization

A new polythioester (PTE), poly(3-mercapto-2-methylpropionate) [P(3M2MP)], and its copolymer with 3-hydroxybutyrate (3HB) were successfully biosynthesized from 3-mercapto-2-methylpropionic acid as a structurally-related precursor. This is the fourth PTE of biological origin and the first to be α-methylated. P(3M2MP) was biosynthesized using an engineered Escherichia coli LSBJ, which has a high molecular weight, amorphous structure, and elastomeric properties, reaching 2600% elongation at break. P(3HB-co-3M2MP) copolymers were synthesized by expressing 3HB-supplying enzymes. The copolymers were produced with high content in the cells and showed a high 3M2MP unit incorporation of up to 77.2 wt% and 54.8 mol%, respectively. As the 3M2MP fraction in the copolymer increased, the molecular weight decreased and the polymers became softer, more flexible, and less crystalline, with lower glass transition temperatures and higher elongations at break. The properties of this PTE were distinct from those of previously biosynthesized PTEs, indicating that the range of material properties can be further expanded by introducing α-methylated thioester monomers.

Biosynthesis of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) From Glucose by Escherichia coli Through Butyryl-CoA Formation Driven by Ccr-Emd Combination

Poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] [P(3HB-co-3HHx)] is a practical kind of bacterial polyhydroxyalkanoates (PHAs). A previous study has established an artificial pathway for the biosynthesis of P(3HB-co-3HHx) from structurally unrelated sugars in Ralstonia eutropha, in which crotonyl-CoA carboxylase/reductase (Ccr) and ethylmalonyl-CoA decarboxylase (Emd) are a key combination for generation of butyryl-CoA and the following chain elongation. This study focused on the installation of the artificial pathway into Escherichia coli. The recombinant strain of E. coli JM109 harboring 11 heterologous genes including Ccr and Emd produced P(3HB-co-3HHx) composed of 14 mol% 3HHx with 41 wt% of dry cellular weight from glucose. Further investigations revealed that the C6 monomer (R)-3HHx-CoA was not supplied by (R)-specific reduction of 3-oxohexanoyl-CoA but by (R)-specific hydration of 2-hexenoyl-CoA formed through reverse β-oxidation after the elongation from C4 to C6. While contribution of the reverse β-oxidation to the conversion of the C4 intermediates was very limited, crotonyl-CoA, a precursor of butyryl-CoA, was generated by dehydration of (R)-3HB-CoA. Several modifications previously reported for enhancement of bioproduction in E. coli were examined for the copolyester synthesis. Elimination of the global regulator Cra or PdhR as well as the block of acetate formation resulted in poor PHA synthesis. The strain lacking RNase G accumulated more PHA but with almost no 3HHx unit. Introduction of the phosphite oxidation system for regeneration of NADPH led to copolyester synthesis with the higher cellular content and higher 3HHx composition by two-stage cultivation with phosphite than those in the absence of phosphite.

Optimization of Culture Conditions for Secretory Production of 3-Hydroxybutyrate Oligomers Using Recombinant Escherichia coli

Poly(3-hydroxybutyrate) [P(3HB)] is the most representative polyhydroxyalkanoate (PHA), which is a storage polyester for prokaryotic cells. P(3HB)-producing recombinant Escherichia coli secretes diethylene glycol (DEG)-terminated 3HB oligomers (3HBO-DEG) through a PHA synthase-mediated chain transfer and alcoholysis reactions with externally added DEG. The purpose of this study was to optimize the culture conditions for the secretory production of 3HBO-DEG with jar fermenters. First, the effects of culture conditions, such as agitation speed, culture temperature, culture pH, and medium composition on 3HBO-DEG production, were investigated in a batch culture using 250-ml mini jar fermenters. Based on the best culture conditions, a fed-batch culture was conducted by feeding glucose to further increase the 3HBO-DEG titer. Consequently, the optimized culture conditions were reproduced using a 2-L jar fermenter. This study successfully demonstrates a high titer of 3HBO-DEG, up to 34.8 g/L, by optimizing the culture conditions, showing the feasibility of a new synthetic strategy for PHA-based materials by combining secretory oligomer production and subsequent chemical reaction.

Enhanced Production of (R)-3-Hydroxybutyrate Oligomers by Coexpression of Molecular Chaperones in Recombinant Escherichia coli Harboring a Polyhydroxyalkanoate Synthase Derived from Bacillus cereus YB-4

The biodegradable polyester poly-(R)-3-hydroxybutyrate [P(3HB)] is synthesized by a polymerizing enzyme called polyhydroxyalkanoate (PHA) synthase and accumulates in a wide variety of bacterial cells. Recently, we demonstrated the secretory production of a (R)-3HB oligomer (3HBO), a low-molecular-weight P(3HB), by using recombinant Escherichia coli expressing PHA synthases. The 3HBO has potential value as an antibacterial substance and as a building block for various polymers. In this study, to construct an efficient 3HBO production system, the coexpression of molecular chaperones and a PHA synthase derived from Bacillus cereus YB-4 (PhaRC_YB4) was examined. First, genes encoding enzymes related to 3HBO biosynthesis (phaRC_YB4, phaA and phaB derived from Ralstonia eutropha H16) and two types of molecular chaperones (groEL, groES, and tig) were introduced into the E. coli strains BW25113 and BW25113ΔadhE. As a result, coexpression of the chaperones promoted the enzyme activity of PHA synthase (approximately 2–3-fold) and 3HBO production (approximately 2-fold). The expression assay of each chaperone and PHA synthase subunit (PhaR_YB4 and PhaC_YB4) indicated that the combination of the two chaperone systems (GroEL-GroES and TF) supported the folding of PhaR_YB4 and PhaC_YB4. These results suggest that the utilization of chaperone proteins is a valuable approach to enhance the formation of active PHA synthase and the productivity of 3HBO.

Development of Thin Vibration Sheets Using a Shape Memory Alloy Actuator for the Tactile Feedback of Myoelectric Prosthetic hands

Because the current myoelectric prosthetic hand does not have a tactile function, the user must always check the condition of the prosthetic hand. Various studies on sensory feedback have been conducted to address this problem, but several devices used in them cannot be integrated with artificial limbs, and wearing the devices is a burden on the user. To solve this problem, we developed thin vibration stimulation sheets using shape memory alloy (SMA) actuators. We then conducted an experiment on the effect of the change in shape at the contact part between the sheet and the skin on perception and confirmed that it would be easier to perceive vibration when the skin was deformed in a wider range. In addition, we investigated the number of distinguishable stimulus intensity levels and identification of stimulus positions. According to the results, the stimulus presented by the developed vibration sheet could be identified in three stages without learning about the stimulus, and the stimulation position by the vibration sheet could be identified with the same or higher accuracy as that of the disk-type vibration motor used in the existing research, although the accuracy decreased when vibrations were presented simultaneously.

Microbial oversecretion of (R)-3-hydroxybutyrate oligomer with diethylene glycol terminal as a macromonomer for polyurethane synthesis

Poly((R)-3-hydroxybutyrate) (P(3HB)) is a polyester that is synthesized and accumulated in many prokaryotic cells. Recently, a new culture method for the secretion of the intracellularly synthesized (R)-3-hydroxybutyrate oligomer (3HBO) from recombinant Escherichia coli cells was developed. In this study, we attempted to produce microbial 3HBO capped with a diethylene glycol terminal (3HBO-DEG) as a macromonomer for polymeric materials. First, we prepared recombinant E. coli strains harboring genes encoding various polyhydroxyalkanoate (PHA) synthases (PhaC, PhaEC or PhaRC) that can incorporate chain transfer (CT) agents such as DEG into the polymer's terminal and generate CT end-capped oligomers. To this end, each strain was cultivated under DEG supplemental conditions, and the synthesis of 3HBO-DEG was confirmed. As a result, the highest secretory production of 3HBO-DEG was observed for the PHA synthase derived from Bacillus cereus YB-4 (PhaRC_YB4). To evaluate the usability of the secreted 3HBO-DEG as a macromonomer, 3HBO-DEG was purified from the culture medium and polymerized with 4,4'-diphenylmethane diisocyanate as a spacer compound. Characterization of the polymeric products revealed that 3HBO-based polyurethane was successfully obtained and was a flexible and transparent noncrystalline polymer, unlike P(3HB). These results suggested that microbial 3HBO-DEG is a promising platform building block for synthesizing polyurethane and various other polymers.

An apparatus based on an atomic force microscope for implementing tip-controlled local breakdown

Solid-state nanopores are powerful tools for sensing of single biomolecules in solution. Fabrication of solid-state nanopores is still challenging, however; in particular, new methods are needed to facilitate the integration of pores with larger nanofluidic and electronic device architectures. We have developed the tip-controlled local breakdown (TCLB) approach, in which an atomic force microscope (AFM) tip is brought into contact with a silicon nitride membrane that is placed onto an electrolyte reservoir. The application of a voltage bias at the AFM tip induces a dielectric breakdown that leads to the formation of a nanopore at the tip position. In this work, we report on the details of the apparatus used to fabricate nanopores using the TCLB method, and we demonstrate the formation of nanopores with smaller, more controlled diameters using a current limiting circuit that zeroes the voltage upon pore formation. Additionally, we demonstrate the capability of TCLB to fabricate pores aligned to embedded topographical features on the membranes.

A Novel Diagnostic System for Infectious Diseases Using Solid-State Nanopore Devices

Nanopore-based diagnostic systems are a promising tool for counting viruses in a specimen one by one. However, despite intensive R&D efforts, it remains difficult to recognize virus subtypes by nanopore devices. We thus propose a novel diagnostic system that combines a specialized virus recognition procedure with a nanopore detection procedure. This recognition procedure consists of three steps: 1) capture target viruses using specific probes for recognition; 2) release captured targets; and 3) detect released targets by nanopore. Proof-of-concept tests are conducted using avidin-modified fluorescent particles (as a model for viruses) and biotin-modified alkane thiol (as a model for probes). The avidin-modified particles are confirmed to be captured on electrode by biotin-modified probes and then, the particles are electrochemically released from the electrode. Consequently, the released particles are successfully detected by nanopore devices. Furthermore, the concept is also proved by using human influenza viruses (H1N1, A/PR/8/34) and sugar chain (6'-sialyllactose)-modified probes. This suggests that our concept is applicable to various infectious diseases by changing probes (ligands).

NADPH supply for poly(3-hydroxybutyrate) synthesis concomitant with enzymatic oxidation of phosphite

Acetoacetyl-CoA reductase (PhaB), involved in poly(3-hydroxybutyrate) [P(3HB)] biosynthesis, requires the coenzyme NADPH as a reducing agent. In this study, the effect of NADPH supply on P(3HB) production was investigated in vitro and in vivo using a phosphite dehydrogenase double mutant (PtxD_EAAR), which catalyzes oxidation of phosphite to phosphate with the generation of NADH and NADPH. In an in vitro assay using purified enzymes, P(3HB) polymerization was observed only when phosphite and PtxD_EAAR were present, confirming that NADPH was supplied to PhaB. In an in vivo assay using Escherichia coli as a production host for P(3HB), the presence of phosphite and PtxD_EAAR did not influence the yield of P(3HB) under normal growth conditions. However, P(3HB) yield increased 3.2-fold in non-growing E. coli cells compared to the control, suggesting that PtxD_EAAR-mediated NADPH generation is coupled with P(3HB) biosynthesis. This study confirmed the use of PtxD_EAAR for supplying NADPH during P(3HB) synthesis in vitro and in vivo.

Heterocyclic boronic acids display sialic acid selective binding in a hypoxic tumor relevant acidic environment

A group of heterocyclic boronic acids demonstrating unusually high affinity and selectivity for sialic acids are described, with strong interactions under the weakly acidic pH conditions associated with a hypoxic tumoral microenvironment.

Boronic acids are well known for their ability to reversibly interact with the diol groups found in sugars and glycoproteins. However, they are generally indiscriminate in their binding. Herein we describe the discovery of a group of heterocyclic boronic acids demonstrating unusually high affinity and selectivity for sialic acids (SAs or N-acetylneuraminic acid), which are sugar residues that are intimately linked with tumor growth and cancer progression. Remarkably, these interactions strengthen under the weakly acidic pH conditions associated with a hypoxic tumoral microenvironment. In vitro competitive binding assays uncovered a significantly higher ability of 5-boronopicolinic acid, one of the derivatives identified in this work as a strong SA-binder, to interact with cell surface SA in comparison to a gold-standard structure, 3-propionamidophenylboronic acid, which has proven to be an efficient SA-binder in numerous reports. This structure also proved to be suitable for further chemical conjugation with a well-preserved SA-binding capability. These findings suggest an attractive alternative to other ongoing boronic acid based chemistry techniques aiming to achieve tumor-specific chemotherapies and diagnoses.

Negative feedback loop of cholesterol regulation is impaired in the livers of patients with Alagille syndrome

AIM

To characterize cholesterol regulation in the liver of patients with Alagille syndrome (AGS).

METHODS

Serum total cholesterol (TC) and total bile acid (TBA) levels were measured in 23 AGS patients. The expressions of genes involved in cholesterol regulation, including low-density lipoprotein receptor (LDLR), scavenger receptor class B type I (SR-BI), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), cholesterol 7α-hydroxylase (CYP7A1), ATP-binding cassette transporter (ABC) A1, and ABCG1/5/8, were measured in liver tissues from five of these patients. Expression of regulators for these genes, including farnesoid X receptor/small heterodimer partner (SHP), liver X receptor α (LXRα) and mature Sterol regulatory element-binding protein 2 (SREBP2) was measured. The expression of mature SREBP2 protein was also examined.

RESULTS

Serum TC and TBA levels were correlated in the AGS patients. Liver cholesterol was also increased compared with controls, and correlated with bile acid contents. LDLR, SR-BI, HMGCR, and ABCGs mRNA expression were upregulated, while CYP7A1 mRNA expression was downregulated in AGS livers. SHP and LXRα mRNA expression was also increased, but maturation of SREBP2 was not suppressed in the patients.

CONCLUSIONS

The major upregulators of liver cholesterol might be increased in AGS patients, indicating an impaired negative feedback mechanism and accelerated liver cholesterol accumulation.

Viper bite during pregnancy: case report

Viper bites in pregnant women have rarely been reported thus far. Moreover, there is no consensus regarding the treatment of such cases. In this paper, the authors report the successful treatment of viper bite during pregnancy without using antivenom.

One-to-one spatially matched experiment and atomistic simulations of nanometre-scale indentation

We have carried out nanoindentation studies of gold in which the indenter is atomically characterized by field-ion microscopy and the scale of deformation is sufficiently small to be directly compared with atomistic simulations. We find that many features of the experiment are correctly reproduced by molecular dynamics simulations, in some cases only when an atomically rough indenter rather than a smooth repulsive-potential indenter is used. Heterogeneous nucleation of dislocations is found to take place at surface defect sites. Using input from atomistic simulations, a model of indentation based on stochastic transitions between continuum elastic-plastic states is developed, which accurately predicts the size distributions of plastic 'pop-in' events and their dependence on tip geometry.

Effect of using stencil masks made by focused ion beam milling on permalloy (Ni81Fe19) nanostructures

Focused ion beam (FIB) milling is a common fabrication technique to make nanostencil masks which has the unintended consequence of gallium ion implantation surrounding milled features in silicon nitride membranes. We observe major changes in film structure, chemical composition, and magnetic behaviour of permalloy nanostructures deposited by electron beam evaporation using silicon nitride stencil masks made by a FIB as compared to stencil masks made by regular lithography techniques. We characterize the stenciled structures and both types of masks using transmission electron microscopy, electron energy loss spectroscopy, energy dispersive x-ray spectroscopy, magnetic force microscopy and kelvin probe force microscopy. All these techniques demonstrate distinct differences at a length scale of a 1-100 nm for the structures made using stencil mask fabricated using a FIB. The origin of these differences seems to be related to the presence of implanted ions, a detailed understanding of the mechanism however remains to be developed.

Anti-TCRβ mAb induces long-term allograft survival by reducing antigen-reactive T cells and sparing regulatory T cells

TCR specific antibodies may modulate the TCR engagement with antigen-MHC complexes, and in turn regulate in vivo T cell responses to alloantigens. Herein, we found that in vivo administration of mAbs specific for mouse TCRβ (H57-597), TCRα or CD3 promptly reduced the number of CD4(+) and CD8(+) T cells in normal mice, but H57-597 mAb most potently increased the frequency of CD4(+) Foxp3(+) Treg cells. When mice were injected with staphylococcal enterotoxin B (SEB) superantigen and H57-597 mAb, the expansion of SEB-reactive Vβ8(+) T cells was completely abrogated while SEB-nonreactive Vβ2(+) T cells remained unaffected. More importantly, transient H57-597 mAb treatment exerted long-lasting effect in preventing T cell responses to alloantigens, and produced long-term cardiac allograft survival (>100 days) in 10 out of 11 recipients. While Treg cells were involved in maintaining donor-specific long-term graft survival, T cell homeostasis recovered over time and immunity was retained against third party allografts. Moreover, transient H57-597 mAb treatment significantly prolonged survival of skin allografts in naïve recipients as well as heart allografts in skin-sensitized recipients. Thus, transient modulation of the TCRβ chain by H57-597 mAb exhibits potent, long-lasting therapeutic effects to control alloimmune responses.

Field deposition from metallic tips onto insulating substrates

The deposition of gold ions from atomic force microscope cantilever tips onto bulk insulating substrates with nearby surface electrodes is discussed. Numerical models of the potential distribution are used to estimate potential barriers for the desorption process. These models indicate deposition height thresholds of 7-10 nm with the tip 20-25 nm from the metallic electrode edge over a KBr surface but greater than 20 nm high for InP/GaAs/InP substrates with a two-dimensional electron gas (2DEG) as the back electrode. Experimental results for the deposition of gold clusters over KBr surfaces near metal electrodes in ultra-high vacuum (UHV) are presented and show promising agreement with calculations of the deposition threshold heights. Deposition of clusters over InP is discussed for comparison and indicates similar trends.

Lung diseases directly associated with rheumatoid arthritis and their relationship to outcome

The outcome and cause of death of each lung disease directly associated with rheumatoid arthritis (RA-LD) have been poorly investigated. A retrospective study was conducted of 144 patients with RA-LD, in whom the median follow-up period after the initial visit for a respiratory examination was 4.5 yrs. A total of 57 patients were identified with usual interstitial pneumonia (UIP), 31 with bronchiectasis, 16 with nonspecific interstitial pneumonia (NSIP), 11 with bronchiolitis, five with organising pneumonia (OP), five with diffuse alveolar damage (DAD) and 19 with combined disease. The 5-yr survival rates were 36.6% in the UIP group, 87.1% in the bronchiectasis group, 93.8% in the NSIP group, 88.9% in the bronchiolitis group, 60.0% in the OP group and 20.0% in the DAD group. Survival of patients with DAD was worse than that of patients with UIP. Overall, survival of patients with UIP was worse than that of patients with bronchiectasis, NSIP or bronchiolitis. Of the 144 patients, 71 (49.3%) died, of whom 58 (81.7%) died due to respiratory lesions. Of patients with RA-LD, patients with DAD experienced the highest mortality, and the survival of patients with UIP was worse than that of patients with NSIP.

Clinical characteristics of acute pulmonary thromboembolism in Japan: results of a multicenter registry in the Japanese Society of Pulmonary Embolism Research

BACKGROUND

Although the incidence of acute pulmonary thromboembolism (APTE) has been increasing in Japan, patient characteristics, management strategies, and outcome have not yet been assessed in large series.

HYPOTHESIS

The present study was designed to investigate the current status of APTE in Japan.

METHODS

Of a total of 533 registry patients with pulmonary thromboembolism, 309 with APTE were analyzed with respect to clinical symptoms and signs, predisposing factors, diagnostic procedures, estimation of deep venous thrombosis, treatment, and clinical course.

RESULTS

Main risk factors were recent major surgery, cancer, prolonged immobilization, and obesity; only a few patients had coagulopathy and 36% were in cardiogenic shock at presentation. The majority of registry patients underwent lung scans or pulmonary angiography; 30% were diagnosed only by lung scanning. Venous ultrasonography was used in only 34 patients, while 188 patients underwent at least one diagnostic procedure for deep venous thrombosis. Thrombolysis was more frequently performed in patients with cardiogenic shock, and only a few patients received thromboembolectomy. In-hospital mortality rate was 14%. In patients with cardiogenic shock, the mortality rate was reduced by thrombolysis. The predictors of in-hospital mortality were male gender, cardiogenic shock, cancer, and prolonged immobilization.

CONCLUSIONS

The patients in this registry had almost the same findings as those in Western patients, except for some points that had the possibility of demonstrating a difference between Westerners and Japanese in the development of APTE. These results can prove especially helpful in planning prospective, randomized trials that will clarify the impact of widely used treatment modalities on the outcome of patients with APTE.

High Q optical fiber tips for NC-AFM in liquid

Non-contact atomic force microscopy is rapidly expanding from ultra-high vacuum to include the study of surfaces and biomolecules in liquids by high resolution imaging and force spectroscopy. This is despite the additional frequency shift noise due to the inherently low Q factor of the cantilever oscillating in a liquid. In this paper we present a tip based on an optical fiber which can operate in liquid with Q factors in excess of 100 using a 'diving bell' arrangement which allows only a small portion of the tip to be submerged. We demonstrate stable imaging and force spectroscopy using this set-up. The tips are based on scanning near-field optical microscopy tips and, when used with NC-AFM, provide a method of combining both high resolution mechanical and fluorescence studies of biomolecules and cells.

Determination of the local contact potential difference of PTCDA on NaCl: a comparison of techniques

There has been increasing focus on the use of Kelvin probe force microscopy (KPFM) for the determination of local electronic structure in recent years, especially in systems where other methods, such as scanning tunnelling microscopy/spectroscopy, may be intractable. We have examined three methods for determining the local apparent contact potential difference (CPD): frequency modulation KPFM (FM-KPFM), amplitude modulation KPFM (AM-KPFM), and frequency shift-bias spectroscopy, on a test system of 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) on NaCl, an example of an organic semiconductor on a bulk insulating substrate. We will discuss the influence of the bias modulation on the apparent CPD measurement by FM-KPFM compared to the DC-bias spectroscopy method, and provide a comparison of AM-KPFM, AM-slope detection KPFM and FM-KPFM imaging resolution and accuracy. We will also discuss the distance dependence of the CPD as measured by FM-KPFM for both the PTCDA organic deposit and the NaCl substrate.

Improved COBAS TaqMan hepatitis C virus test (Version 2.0) for use with the High Pure system: enhanced genotype inclusivity and performance characteristics in a multisite study

We have evaluated the COBAS TaqMan hepatitis C virus (HCV) test (version 2.0) for use with the High Pure system (HCVHPS V2), a new, revised real-time reverse transcription-PCR assay developed to improve the genotype quantitation of version 1.0 (HCVHPS V1). Revisions were made in the wash buffer and in the reverse transcription temperature. The genotype inclusivity of HCVHPS V2 was evaluated at three different sites, using HCVHPS V2, HCVHPS V1, and the COBAS AMPLICOR HCV MONITOR test (version 2.0) (CAHCM). The fully automated COBAS Ampliprep/COBAS TaqMan HCV test was also used in one of the participating laboratories. The mean differences in HCV RNA values between HCVHPS V2 and CAHCM and between HCVHPS V2 and HCVHPS V1 ranged from -0.21 to 0.13 log and from 0.24 to 1.27 log, respectively, with >0.5-log differences for genotypes 2, 3, 4, and 5. With a NIBSC panel of HCV genotypes 1 through 6, the measured HCVHPS V2 values were within 0.25 log of the nominal values for all 6 genotypes. When serial dilutions of genotype-specific clinical HCV specimens were tested, the assay showed a limit of detection between 10 and 20 IU/ml and a linear range of 25 IU/ml to 3.91 x 10(8) IU/ml. Clinical and analytical specificities of 100% were demonstrated with 100 HCV-seronegative specimens as well as with 12 non-HCV members of Flaviviridae and 22 additional microorganisms. These data indicate that HCVHPS V2 is a robust and accurate test for the quantitation of all six HCV genotypes and useful in monitoring viral load in all clinical HCV specimens.

Radiotherapy negates the effect of retroperitoneal nonclosure for prevention of lymphedema of the legs following pelvic lymphadenectomy for gynecological malignancies: an analysis from a questionnaire survey

Using patient questionnaires, we studied the long-term effect of leaving the peritoneum open on the incidence of lymphedema of the legs in patients following pelvic lymphadenectomy for gynecological malignancies. The patients were retrospectively assigned to one of two groups, depending on whether the retroperitoneum was closed or left open at surgery. Three years after surgery, we obtained valid questionnaire responses from 101 patients (43 cervical, 46 endometrial, and 12 ovarian cancers) in the closure group and 83 patients (34 cervical, 40 endometrial, and 9 ovarian cancers) in the nonclosure group. In patients' self-analysis, the overall incidence of lymphedema of the legs was significantly lower in the nonclosure group than in the closure group (25.3% and 50.5%, respectively; P < 0.01). The incidence of lymphedema of the legs was significantly increased by postoperative radiotherapy. Especially in the nonclosure group, the incidence of lymphedema was only 15.8% in patients who did not have radiotherapy, but it increased significantly (44.4%) (P < 0.05) when patients underwent radiotherapy. In conclusion, this questionnaire survey suggested that leaving the retroperitoneum open after lymphadenectomy is significantly effective in reducing the incidence of leg lymphedema, which impairs patients' quality of life more than expected by physicians.

Melanoma differentiation-associated gene-7 (mda-7)/interleukin (IL)-24 induces anticancer immunity in a syngeneic murine model

Previous studies have shown that the human melanoma differentiation-associated gene-7 (mda-7)/interleukin-24 (IL-24) has tumor-suppressor activity in vitro and in vivo. Additionally, in vitro studies using human peripheral blood mononuclear cells indicate that mda-7/IL-24 has TH1 cytokine-like activity. However, the individual properties of mda-7/IL-24 have been previously examined separately. Thus, there is not a single study that has examined both, antitumor and proimmune properties of mda-7/IL-24. Furthermore, the tumor suppressive activity and the cytokine activity of mda-7/IL-24 have not been previously tested in an immunocompetent setting. We therefore in the present study evaluated the antitumor and immune properties of mda-7/IL-24 in a murine syngeneic tumor model. In vitro, adenovirus-mediated mda-7 gene (Ad-mda7) transfer to murine fibrosarcoma (UV2237m; MCA16) and normal (10T1/2) cells significantly inhibited growth (P=0.001) and induced apoptosis in tumor cells but not in normal cells. In vivo, intratumoral administration of Ad-mda7 resulted in significant inhibition of tumor growth (P<0.05), with a subset of mice showing complete tumor regression. We next evaluated the immune potentiation activity of Ad-mda7 in a cancer vaccine model. UV2237m cells transfected with Ad-mda7 and injected into syngeneic immunocompetent C3H mice were unable to grow; however, they did grow in immunocompromised nude mice. These tumor-free C3H mice, when challenged with parental tumor cells experienced no tumor growth, suggesting induction of systemic immunity. Moreover, splenocytes prepared from vaccinated C3H mice demonstrated higher proliferative activity and produced elevated levels of TH1 cytokines compared with those from control mice. An in vitro subset analysis of splenocytes from vaccinated mice demonstrated a significant increase in the CD3(+)CD8(+) but not the CD3(+)CD4(+) cell population (P=0.019). Thus Ad-mda7 treatment of syngeneic tumors induces tumor cell death and promotes immune activation, leading to anticancer immunity.

Characterization of 17beta-hydroxysteroid dehydrogenase type 4 in human ovarian surface epithelial cells

The human ovarian surface epithelium (hOSE) is a single layer of mesothelial-type primitive epithelial cells that are potential estrogen targets. It has been reported that hOSE cells can produce estrogen. However, the mechanisms that regulate estrogen level(s) in hOSE cells are not yet known. To elucidate the enzymes involved in these reactions, we examined gene expression of 17beta-hydroxysteroid dehydrogenases (17beta-HSDs) in primary hOSE (POSE) and OSE2a cells using RT-PCR. We found that POSE cells and cells of the immortalized hOSE line, OSE2a, bidirectionally converted estrone (E1) and 17beta-estradiol (E2). Both cell types expressed mRNA for 17beta-HSD type 1 (17beta-HSD1), suggesting that the enzyme is involved in the E1 to E2 conversion. Interestingly, both cells expressed 17beta-HSD4 mRNA but not 17beta-HSD2 mRNA. We prepared an antibody against the carboxyl terminal of 17beta-HSD4 (anti-17beta-HSD4 antibody), which recognized the 80 and 48 kDa proteins in POSE and OSE2a cells based on immunoblot analysis. Furthermore, immunohistochemical study revealed the presence of 17beta-HSD4 in hOSE cells in the human ovary. These results suggest that 17beta-HSD4 is involved in estrogen inactivation and may protect against an excessive accumulation of E2 in hOSE cells.

Transient increase in squamous cell carcinoma antigen expression in cultured cervical carcinoma CaSki cells in response to exposure to cis-diamminedichloroplatinum

The present study was conducted to elucidate the molecular mechanism underlying the transient increase in circulating squamous cell carcinoma antigen (SCC Ag) levels in response to CIS-diamminedichloroplatinum (CDDP) infusion using an in vitro model. The uterine cervical squamous carcinoma CaSki cells were cultured for 72 h after 3 h exposure to 5.0 microg/ml CDDP. The effects of CDDP exposure on the proliferative activity and apoptosis in cultured CaSki cells were determined by bromodeoxyuridine (BrdU) uptake and cell counting and by the TUNEL assay, respectively. SCC Ag levels in cultured CaSki cells and culture media were determined with the use of SCC-RIA kit. The expression of SCC Ag-1 mRNA and SCC Ag-2 mRNA in cultured CaSki cells was assessed using semiquantitative RT-PCR with Southern blot analysis. The number of BrdU-positive CaSki cells significantly decreased 6 h after exposure to CDDP, whereas the apoptosis-positive rate of cultured CaSki cells significantly increased 12 h after the CDDP exposure. The number of cultured CaSki cells significantly decreased 72 h after the CDDP exposure. The total SCC Ag protein levels in both cultured CaSki cells and the culture media after the 3-hour CDDP exposure increased in a time-dependent manner during the subsequent incubation for 48 h. Semiquantitative RT-PCR revealed that the expression levels of both SCC Ag-1 and SCC Ag-2 mRNA increased (1.7- and 2.7-fold, respectively) 12 h after the exposure to CDDP relative to those before the subsequent cultures. Exposure of uterine cervical squamous carcinoma CaSki cells to CDDP resulted in a transient increase in SCC Ag protein and mRNA expression in those cells during the initial 12 h after the exposure, being associated with decreased proliferative activity and increased apoptosis of those cells.

Effect of cis-diammine dichloroplatinum on vascular endothelial growth factor expression in uterine cervical carcinoma

PURPOSE OF INVESTIGATION

In this study, we investigated the effects of cis-diammine dichloroplatinum (CDDP) on VEGF mRNA expression and VEGF production in uterine cervical carcinoma tissues obtained from patients with locally advanced disease and in CaSki cells cultured in vitro.

METHODS

VEGF in cultured CaSki cells and in the culture media was measured using a sensitive enzyme-linked immunosorbent assay (ELISA) before and 24 h, 48 h and 72 h after 3 h exposure to CDDP. VEGF mRNA expression in CaSki cells was assessed by the semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) before and 24 h and 48 h after 3 h exposure to CDDP. We also examined the effect of CDDP on microvessel counts in uterine cervical carcinoma tissues obtained before and after high-dose CDDP intraarterial chemotherapy. Immunohistochemical staining using a monoclonal antibody against CD34 was carried out with cervical carcinoma tissue specimens, and microvessel counts were quantified by counting vessels.

RESULTS

CDDP treatment resulted in significant increases in not only VEGF concentrations in cultured CaSki cells and culture media but also in VEGF mRNA expression levels in cultured CaSki cells in a time-dependent and dose-dependent manner compared to untreated controls (p < 0.05, n = 5). On the other hand, VEGF concentrations and microvessel counts in cervical carcinoma tissues were significantly lower in cases with complete response (CR) and partial response (PR), compared to those before treatment (p < 0.05, n = 5 ). By contrast, in cases with no change (NC) to CDDP, both VEGF concentrations and microvessel counts did not decrease and rather showed a somewhat increase compared with levels prior to the treatment.

CONCLUSIONS

These results suggest that CDDP-induced increases in VEGF production by cervical carcinoma cells may stimulate angiogenesis in the tumor lesion after CDDP treatment.

Influence of hemodialysis on echocardiographic Doppler indices of the left ventricle: changes in parameters of systolic and diastolic function and Tei index

AIMS

Numbers of previous studies have evaluated the influence of dialysis-induced altered loading condition on Doppler-echocardiographic indices of left ventricle in patients with chronic renal failure. It has been suggested that most of Doppler-derived indices are preload-dependent. On the other hand, there are no studies that have evaluated the influence of hemodialysis on Tei index; a new Doppler-derived index obtained by isovolumetric contraction time plus isovolumetric relaxation time divided by ejection time. The aim of this study is to evaluate whether Tei index is also influenced by dialysis-induced altered loading condition as well as other Doppler-derived indices, and to assess the possibility that Tei index is also preload-dependent.

PATIENTS AND METHODS

Thirty-two patients with chronic renal failure (21 men and 11 women, aged 48-93 years) on maintenance hemodialysis were evaluated for Doppler-derived indices before and after hemodialysis. We studied parameters of diastolic function (peak velocities of mitral inflow in early diastole (E) and late diastole from atrial filling (A), ratio of A to E (A/E), deceleration time (DT), and isovolumetric relaxation time (IRT)), parameters of systolic function (ejection time (ET), pre-ejection period (PEP), ratio of PEP to ET (PEP/ET), and isovolumetric contraction time (ICT)) and Tei index.

RESULTS

Hemodialysis resulted in significant decreases in E, increase in A/E, prolongation of IRT, no change in A and DT; significant prolongation of ICT and PEP, shortening of ET, and increase in PEP/ET and a significant increase in Tei index (0.42 +/- 0.16 vs 0.51 +/- 0.16, p < 0.0001). When patients were subdivided into 2 groups based on weight loss after hemodialysis (> or = 1.5 kg and < 1.5 kg), only the group that lost > or = 1.5 kg had significant change in Tei index before and after hemodialysis (0.40 +/- 0.15 vs 0.52 +/- 0.17, p = 0.0002).

CONCLUSION

This study demonstrates that not only most of Doppler-derived indices but also Tei index is affected by dialysis-induced altered loading condition and suggests that Tei index is possibly preload-dependent.

Role of SEREX-defined immunogenic wild-type cellular molecules in the development of tumor-specific immunity

Recognition of altered self-antigens in tumor cells by lymphocytes forms the basis for antitumor immune responses. The effector cells in most experimental tumor systems are CD8(+) T cells that recognize MHC class I binding peptides derived from molecules with altered expression in tumor cells. Although the need for CD4(+) helper T cells in regulating CD8(+) T cells has been documented, their target epitopes and functional impact in antitumor responses remain unclear. We examined whether broadly expressed wild-type molecules in murine tumor cells eliciting humoral immunity contributed to the generation of CD8(+) T cells and protective antitumor immune responses to unrelated tumor-specific antigens [mutated ERK2 (mERK2) and c-erbB2/HER/neu (HER2)]. The immunogenic wild-type molecules, presumably dependent on recognition by CD4(+) helper T cells, were defined by serological analysis of recombinant cDNA expression libraries (SEREX) using tumor-derived lambda phage libraries screened with IgG antibodies of hosts bearing transplanted 3-methylchoranthrene-induced tumors. Coimmunization of mice with plasmids encoding SEREX-defined murine wild-type molecules and mERK2 or HER2 led to a profound increase in CD8(+) T cells specific for mERK2 or HER2 peptides. This heightened response depended on CD4(+) T cells and copresentation of SEREX-defined molecules and CD8(+) T cell epitopes. In tumor protection assays, immunization with SEREX-defined wild-type molecules and mERK2 resulted in an inhibition of pulmonary metastasis, which was not achieved by immunization with mERK2 alone.

Limitations of successive transradial approach in the same arm: the Japanese experience

The transradial approach (TRA) has been used for diagnostic and interventional cardiology. It has not previously been determined how many times the same radial artery can be cannulated without complications. A total of 812 patients (502 men and 310 women) underwent angiography or angioplasty via the TRA between 1997 and 1999 at our institution with a total of 1,438 procedures. Sheaths were 5 (55%) or 6 Fr (45%). Dropout rates of 3.5% and 7.9% were found at the second TRA attempt in the men and the women, respectively. Of the 62 TRA failures, 56 (90%) were due to narrowing or occlusion of the radial artery after the previous TRA procedure. A third TRA procedure was possible in 90% of the men and 80% of the women. A fifth TRA procedure was possible in 70% of the men and 50% of the women. The dropout rates for TRA increased as successive punctures were performed. This was primarily due to vessel narrowing and occlusion occurring as a function of multiple punctures.