Transparent Patternable Large-Area Graphene p-n Junctions by Photoinduced Electron Doping

We present a novel approach to achieve n-type doping in graphene and create graphene p-n junctions through a photoinduced electron doping method using photobase generators (PBGs). The unique properties of PBGs allow us to spatially and temporally control the doping process via light activation. The selective irradiation of specific regions on the graphene film enables switching their doping from p- to n-type, as confirmed by changes in the electromotive force and Seebeck and Hall coefficients. We demonstrate a stable (over 2 months) high electron mobility exceeding 1000 cm2 V-1s-1 using Hall effect measurements. The precise control of doping and the creation of p-n junctions in graphene offer exciting possibilities for various electronic, optoelectronic, and thermoelectric applications. Furthermore, we fabricate transparent graphene thermocouples with a high electromotive force of approximately ca. 80 μV/K, which validates the reliability and effectiveness of our approach for temperature sensing applications. This work paves the way for high-performance graphene-based electronic devices via controlled doping and patterning techniques. These findings provide valuable insights for the practical implementation of graphene in various fields.

High-Performance Isotropic Thermo-Electrochemical Cells Using Agar-Gelled Ferricyanide/Ferrocyanide/Guanidinium

An isotropic thermo-electrochemical cell is introduced with a high Seebeck coefficient (S _e) of 3.3 mV K^-1 that uses a ferricyanide/ferrocyanide/guanidinium-based agar-gelated electrolyte. A power density of about 20 µW cm^-2 is achieved at a temperature difference of about 10 K, regardless of whether the heat source is on the top or bottom section of the cell. This behavior is very different from that of cells with liquid electrolytes, which exhibit high anisotropy, and for which high S _e values are achieved only by heating the bottom electrode. The guanidinium-containing gelatinized cell does not exhibit steady-state operation, but its performance recovers when disconnected from the external load, suggesting that the observed power drop under load conditions is not due to device degeneration. The large S _e value and isotropic properties can mean that the novel system represents a major advancement from the standpoint of harvesting of low-temperature heat, such as body heat and solar thermal heat.

Design and synthesis of proton-dopable organic semiconductors

This paper shows how protonated 3,4-ethylene dioxythiophene moieties can be used as an end group to make organic conductors. An organic semiconductor 2,5-bis(5-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-3-dodecylthiophen-2-yl)thieno[3,2-b]thiophene is designed and synthesized. This molecule could be doped by protonic acid in both solution and solid-state, resulting in a broad absorption in the near-infrared range corresponding to polaron and bipolaron absorption. Electrical conductivity of ca. 0.1 S cm⁻¹ was obtained at 100 °C (to avoid the water uptake by the acid). The adducts with protons bound at the end-thiophene α-position were confirmed by ¹H Nuclear Magnetic Resonance spectra.

The use of protonated 3,4-ethylenedioxythiophene moieties as an end group could be a promising approach to prepare organic conductors.

Thermoelectrochemical Cells Based on Ferricyanide/Ferrocyanide/Guanidinium: Application and Challenges

Ferricyanide/ferrocyanide/guanidinium-based thermoelectrochemical cells have been investigated under different loading conditions in this work. Compared with ferricyanide/ferrocyanide-based devices, the device with guanidinium-added electrolytes shows higher power and energy densities. We observed that the enhanced performance is not due to the ionic Seebeck effect of guanidinium but because of the configuration entropy change resulting from the selective binding of Gdm+ to Fe(CN)64-. However, the device with guanidinium-added electrolyte does not show steady-state operation. The two possible reasons include (1) the difficult diffusion of Fe(CN)63- into the crystal layer of (Gdm+)n[Fe(CN)64-] at the hot electrode and (2) the difficult precipitation of (Gdm+)n[Fe(CN)64-] formed at the cold side upon the binding of the reduced Fe(CN)64- with Gdm+. Nevertheless, the performance recovers once the device is disconnected from the external loading. Due to the high thermopower after adding guanidinium, we successfully fabricate self-powered sensors by connecting four flexible cells in series. The sensors can transfer humidity, temperature, and air pressure data wirelessly using body heat. Therefore, ferricyanide/ferrocyanide/guanidinium is a promising electrolyte material for applications of low-grade energy harvesting.

Control of anisotropic conduction of carbon nanotube sheets and their use as planar-type thermoelectric conversion materials

The large anisotropic thermal conduction of a carbon nanotube (CNT) sheet that originates from the in-plane orientation of one-dimensional CNTs is disadvantageous for thermoelectric conversion using the Seebeck effect since the temperature gradient is difficult to maintain in the current flow direction. To control the orientation of the CNTs, polymer particles are introduced as orientation aligners upon sheet formation by vacuum filtration. The thermal conductivities in the in-plane direction decrease as the number of polymer particles in the sheet increases, while that in the through-plane direction increases. Consequently, a greater temperature gradient is observed for the anisotropy-controlled CNT sheet as compared to that detected for the CNT sheet without anisotropy control when a part of the sheet is heated, which results in a higher power density for the planar-type thermoelectric device. These findings are quite useful for the development of flexible and wearable thermoelectric batteries using CNT sheets.

Outstanding Electrode-Dependent Seebeck Coefficients in Ionic Hydrogels for Thermally Chargeable Supercapacitor near Room Temperature

Thermoelectric power generation from waste heat is an important component of future sustainable development. Ion-conducting materials are promising candidates because of their high Seebeck coefficients. This study demonstrates that ionic hydrogels based on imidazolium chloride salts exhibit outstanding Seebeck coefficients of up to 10 mV K^-1. Along with their relatively high ionic conductivities (1.6 mS cm^-1) and extremely low thermal conductivities (∼0.2 W m^-1 K^-1), these hydrogels have good potential for use in heat recovery systems. The voltage behavior in response to temperature difference (stable or transient) differs significantly depending on the metal electrode material. We evaluated the electrode-dependent temperature sensitivity of the double layer capacitance of these hydrogels, which revealed that the thermally induced polarization of ions at the interface is one of the main contributors to the thermovoltage. Our results demonstrate the potential capability for ion and metal interactions to be used as an effective baseline for exploring ionic thermoelectric materials and devices. The developed thermoelectric supercapacitor exhibits reversible charging-discharging behavior under repeated disconnecting-connecting of an external load with a constant temperature difference, which offers a novel strategy for heat-to-electricity energy conversion from steady-temperature heat sources.

Reversible Protonic Doping in Poly(3,4-Ethylenedioxythiophene)

In this study, poly(3,4-ethylenedioxythiophene), a benchmark-conducting polymer, was doped by protons. The doping and de-doping processes, using protonic acid and a base, were fully reversible. We predicted possible doping sites along the polymer chain using density functional theory (DFT) calculations. This study sheds potential light and understanding on the molecular design of highly conductive organic materials.

Humidity control in a closed system utilizing conducting polymers

In this study, we demonstrate that conducting polymers could be ideal materials for continuously managing humidity in a wide range of enclosed spaces. We demonstrate a simple battery-driven humidity control unit to manage the humidity in a closed environment and studied humidity-responsive nanocapsules using Zn-coordinated lipid nanovesicles. This study not only promises new applications for conducting polymers but also provides an easy approach for fabricating chambers with a controlled environment, which are often used by physicists, chemists, and biologists.

In this study, we demonstrate that conducting polymers could be ideal materials for continuously managing humidity in a wide range of enclosed spaces.

Electrical transport and thermoelectric properties of boron carbide nanowires

The electrical transport and thermoelectric property of boron carbide nanowires synthesized by a carbothermal method are reported. It is demonstrated that the nanowires achieve a higher Seebeck coefficient and power factor than those of the bulk samples. The conduction mechanism of the nanowires at low temperatures below 300 K is different from that of the sintered-polycrystalline and single-crystal bulk samples. In a temperature range of 200-450 K, there is a crossover between electrical conduction by variable-range hopping and phonon-assisted hopping. The inhomogeneous carbon concentration and planar defects, such as twins and stacking faults, in the nanowires are thought to modify the bonding nature and electronic structure of the boron carbide crystal substantially, causing differences in the electrical conductivity and Seebeck coefficient. The effect of boundary scattering of phonon at nanostructured surface on the thermal conductivity reduction is discussed.

Photoinduced Dedoping of Conducting Polymers: An Approach to Precise Control of the Carrier Concentration and Understanding Transport Properties

Exploring the various applications of conjugated polymers requires systematic studies of their physical properties as a function of the doping density, which, consequently, calls for precise control of their doping density. In this study, we report a novel solid-state photoinduced charge-transfer reaction that dedopes highly conductive polyelectrolyte complexes such as poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate). Varying the UV-irradiation time of this material allows the carrier density inside the film to be precisely controlled over more than 3 orders of magnitude. We extract the carrier density, carrier mobility, and Seebeck coefficient at different doping levels to obtain a clear image of carrier-transport mechanisms. This approach not only leads to a better understanding of the physical properties of the conducting polymer but also is useful for developing applications requiring patterned, large-area conducting polymers.

Recent Progress on PEDOT-Based Thermoelectric Materials

The thermoelectric properties of poly(3,4-ethylenedioxythiophene) (PEDOT)-based materials have attracted attention recently because of their remarkable electrical conductivity, power factor, and figure of merit. In this review, we summarize recent efforts toward improving the thermoelectric properties of PEDOT-based materials. We also discuss thermoelectric measurement techniques and several unsolved problems with the PEDOT system such as the effect of water absorption from the air and the anisotropic thermoelectric properties. In the last part, we describe our work on improving the power output of thermoelectric modules by using PEDOT, and we outline the potential applications of polymer thermoelectric generators.

Experimental Studies on the Anisotropic Thermoelectric Properties of Conducting Polymer Films

We reported general methods for studying the thermoelectric properties of a polymer film in both the in-plane and through-plane directions. The bench-mark PEDOT/PSS films have highly anisotropic carrier transport properties and thermal conductivity. The anisotropic carrier transport properties can be explained by the lamellar structure of the PEDOT/PSS films where the PEDOT nanocrystals could be isolated by the insulating PSS in the through-plane direction. The anisotropic thermal conductivity was mainly attributed to the lattice contribution from PSS because the polymer chain is oriented along the substrate.

Polymer thermoelectric modules screen-printed on paper

Screen-printed polymer thermoelectric devices provided sufficient power to illuminate light-emitting diodes.

Self-aligned formation of sub 1 nm gaps utilizing electromigration during metal deposition

We developed a procedure for the fabrication of sub 1 nm gap Au electrodes via electromigration. Self-aligned nanogap formation was achieved by applying a bias voltage, which causes electromigration during metal evaporation. We also demonstrated the application of this method for the formation of nanogaps as small as 1 nm in width, and we found that the gap size can be controlled by changing the magnitude of the applied voltage. On the basis of the electric conductance and surface-enhanced Raman scattering (SERS) measurements, the fabricated gap size was estimated to be nearly equal to the molecular length of 1,4-benzenedithiol (BDT). Compared with existing electromigration methods, the new method provides two advantages: the process currents are clearly suppressed and parallel or large area production is possible. This simple method for the fabrication of a sub 1 nm gap electrode is useful for single-molecule-sized electronics and opens the door to future research on integrated sub 1 nm sized nanogap devices.

Morphological change and mobility enhancement in PEDOT:PSS by adding co-solvents

Adding ethylene glycol (EG) to a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) solution improves the crystallinity of the PEDOT and the ordering of the PEDOT nanocrystals in solid films. The carrier-mobility enhancement is confirmed by using ion-gel transistors combined with in situ UV-vis-NIR spectroscopy.

Pressure-dependent hydrogen permeability extended for metal membranes not obeying the square-root law

Hydrogen permeability of metal membranes is generally defined by the square-root law, as the proportional coefficient of permeation flux to the square-root difference of the pressures on both sides of the membrane. However, deviation from the law has been widely reported for palladium, niobium, etc. Although n-th power instead of the square root has often been employed to determine permeability for these membranes, it has no theoretical base. These approaches do not consider concentration dependency of hydrogen diffusivity in the membrane. This study theoretically extended the definition of permeability by taking it into account, where square root of pressure was used throughout. The resultant permeability depended on pressure. This approach had the following four characteristics. First, the permeability could be qualitatively linked with pressure-dependent solution and diffusion coefficients. For this purpose, the solution coefficient was also extended from Sieverts' law. Second, the permeability could be easily evaluated from permeation flux dependent on feed-side pressure, usually measured in membrane study. Third, this approach enabled comparison of permeation ability irrespective of obeying permeation law. Fourth, permeation flux could be estimated for any pressure conditions visually and analytically. Thus, analytically estimated values were more precise than those using the conventional square-root law. These characteristics are successfully demonstrated using experimental results obtained not only for a palladium membrane in this study but also for palladium and niobium membranes in the literature.

[Aortic valve repair with minimal access "J" sternotomy]

Recently many cardiovascular operations have been performed with minimally invasive cardiac surgery (MICS). It is reported that MICS is superior to standard full sternotomy in regard to cosmetic and post-operative recovery. In our institution, aortic valve repair operations have been performed to aortic valve insufficiency. This time, we performed aortic valve repair by minimal access "J" sternotomy. A 63-year-old male with degenerative aortic regurgitation underwent aortic valve repair by MICS. He had experienced dyspnea on exertion 7 days before admission. Preoperative transthoracic echocardiogram showed the grade of aortic regurgitation (AR) was severe. Surgery was successful and the grade of AR became trivial. This combined procedure have merits for patients because of freedom from anticoagulation and small incision. Such combined surgery may be indicated in the treatment in a subset of patients with degenerative AR.

Selection of surgical methods for infected infrarenal abdominal aortic aneurysms

BACKGROUND

There is no standard treatment for patients with infected abdominal aortic aneurysm (AAA). To determine the basis for selection of a surgical method, we reviewed our experiences with all patients who underwent surgery for infected infrarenal AAA.

METHODS

Between 1993 and 2000, 6 patients with infected infrarenal AAA underwent surgery. Extra-anatomic bypass grafting was performed in 2 of 3 patients with infection extending into the retroperitoneum. In situ grafting was performed in 3 patients with localized infection and in 1 patient with extended infection.

RESULTS

Severe peritonitis occurred in 2 patients with extended infection in the early postoperative phase. One patient, who had undergone in situ grafting, died of sepsis. The other patient, who had undergone extra-anatomic bypass grafting, was treated by continuous irrigation with an electrolyzed strong acid aqueous solution (ESAAS). He recovered gradually and was discharged. After a follow-up period with a mean of 40 months (range: 17-102 months), all 5 patients who survived surgery are alive and asymptomatic.

CONCLUSIONS

It was suggested that the method used for revascularization should be selected based on the degree of diffusion of infection. For a patient with extended infection, postoperative continuous irrigation with ESAAS appears to be effective in eradicating retroperitoneal infection.

[Redo coronary artery bypass grafting using the patent left internal thoracic artery graft as an in flow with composite internal thoracic artery Y grafting; report of a case]

In redo coronary artery bypass grafting (CABG), graft selection and revascularization methods are major problems. We experienced a redo-CABG with occluded previous vein grafts. These grafts were to the circumflex artery and right coronary artery. We conducted operation using cardiopulmonary bypass. We at this operation, chose right internal thoracic artery (RITA) as a conduit and anastomosed it to the side of functioning left internal thoracic artery (LITA) graft, and then diogonal branch, posterolateral branch, and atrioventricular branch were revascularized with the RITA. Post operative course was uneventful. Internal thoracic artery (ITA) is superior to vein graft and other arterial graft as to long term patency. We believe composite Y graft with the use of bilateral ITA can be one of the revascularization strategy in redo CABG.

Assay of spherical cell surface molecules by thermal lens microscopy and its application to blood cell substances

To detect and quantitate uneven cell surface molecules, such as blood group antigens on a blood cell and immunoglobulin molecules on a mast cell, an improved method of thermal lens microscopy was employed. The antigen molecules were immunologically stained with their antibodies, which were labeled with colloidal gold. Since the surface of the biological cells was not flat but spherical, the focal point of the probe laser beam inevitably deviated from the sample surface on the moving stage. Therefore, the deviation of the focal point of the probe beam was corrected by adjusting the phase of the signal. Using this technique, a three-dimensional antigen distribution on each cell surface was imaged. Despite the convex surface of cells, labeled colloidal gold was correctly quantified. In the measurement of erythrocyte antigens, a small quantity of Lewis antigens was successfully detected on the umbilical cord erythrocytes. Immunoglobulin E on a mast cell, derived from the allergic human mucosa fungus, was also observed by this method, and the distribution of IgE molecules on the cell surface was quantitatively imaged. A thermal lens microscope, which measures spherical samples correcting the deviation, made it possible for us to observe and assay the substances on biological specimens that have complicated forms, such as living cells in vivo or in situ.

Survival and sinus rhythm maintenance after modified Cox/maze procedure and mitral valve operation in patients with chronic atrial fibrillation

OBJECTIVE

Sinus rhythm gained after the Cox/maze procedure concomitant with mitral valve operation has demonstrated long-term attrition during the follow-up, no information exists on whether the type of mitral valve operation--(repair vs. replacement)--affects this sinus rhythm maintenance rate. We retrospectively studied patients undergoing concomitant mitral valve operation and Cox/maze procedure to answer this question.

METHODS

Between April 1993 and August 1995, 87 consecutive patients--35 men and 52 women (mean age: 59.3 years)--with chronic atrial fibrillation and mitral valve disease underwent the modified Cox/maze procedure and concomitant mitral valve operation, with 56 having mitral valve repair (repair group) and 31 mitral valve replacement (replacement group). Patients were followed up and changes in rhythm studied retrospectively.

RESULTS

Follow-up for a mean 51.3 +/- 11.6 months was completed in 82 of 83 long-term survivors (99%). Repair group surgery survival was 98.1 +/- 1.9% at 1 year and 94.2 +/- 3.2% at 5 based on the Kaplan-Meier method. Replacement group surgery survival was 85.7 +/- 5.9% at 1 year and 82.9 +/- 6.4% at 5. Probability in sinus rhythm maintenance for the repair group at 1 year was 88.6 +/- 5.4% and at 5 years was 67.6 +/- 9.1%. Probability in sinus rhythm maintenance for the replacement group at 1 year was 95.7 +/- 4.3% and at 5 years was 65.0 +/- 11.1%.

CONCLUSIONS

Medium-term results after the Cox/maze III procedure concomitant with mitral valve operation are good. The attrition of sinus rhythm maintenance appears similar by the completion of 5-year follow-up.

[Genotyping of blood-groups by denaturant gradient gel electrophoresis (DGGE)]

The denaturant gradient gel electrophoresis (DGGE) method was used in order to simultaneously estimate the genotypes of different factors in a gel plate consisting of one sheet. A genotype analysis of the blood groups (MN, Duffy, Kidd type) and serotype (Gc system) was carried out. DNA samples extracted from the leucocytes of volunteers, whose blood group had already been proven, were used. The PCR amplification fragments were amplified from the gene which controlled each blood group. The primers were designed in order to analyze genotypes with from 1-3 base substitutions in the amplification product. The concentration of the denaturant most suitable for the DGGE method to detect each genotype of the blood groups (MN, Duffy, Kidd type and Gc system) was calculated using a computer simulation method. The denaturant concentration limit of the gel which was suitable for performing a DGGE analysis was determined to range from 15-36%. Electrophoresis was performed at 60 degrees C and with 100 V using this gel on each amplification fragment for 3 hours. The gel after electrophoresis was treated in ethidium bromide in order to detect the DNA band. The genotype (M/M, M/N and N/N) of the MN blood group, the genotype (Fya/Fya, Fya/Fyb and Fyb/Fyb) of the Duffy blood group, the genotype (Jka/Jka, Jka/Jkb and Jkb/Jkb) of the Kidd blood group and each allele (GC*1S, GC*1F and GC*2) of the Gc system were all simultaneously distinguished in one plate. As a result, it was possible to estimate multiple gene polymorphism, while substituting bases 1-3, by PCR, DGGE and ethidium bromide staining. The polymorphic results obtained using this DGGE method is very useful for cases in which a multiple gene analysis is required such as for the personal identification.

Autophagy in embryonic erythroid cells: its role in maturation

Yolk sac-derived embryonic erythroid cells differentiate synchronously in the peripheral blood of Syrian hamster. The stage of differentiation on day 10 of gestation is equivalent to polychromatophilic erythroblast stage and that on day 13 is equivalent to the reticulocyte stage in adult animals. The cytoplasm of embryonic erythroid cells became scant and devoid of most organelles on day 12 of gestation. In addition, there were very few non-erythroid cells in circulation before day 13. Thus the embryonic erythroid cells serve a pure and synchronous system to study the mechanisms of terminal differentiation. The number of mitochondria in the embryonic erythroid cells decreased to about 10% of the initial number during the period between day 10 and day 12 of gestation. In contrast, the frequency of autophagy of mitochondria increased 4.6-fold in the same period. The cytochrome c content of the cell decreased as the mitochondria became extinct. However, release of cytochrome c into the cytoplasm was not detectable through day 10-13 of gestation, suggesting that the mitochondria were digested within a closed compartment. Decomposed mitochondria and ferritin particles were detected in lysosomes by electron microscopy on and after day 12 of gestation, which also suggested digestion in a closed compartment. Mitochondrial ATP synthase subunit c, which is known to be a protease-refractory protein, was retained in the cells even after the disappearance of mitochondria, indicating that most of the mitochondria were not extruded from the cells. The digestion of mitochondria in autolysosomes may allow the cells to escape from rapid apoptotic cell death through concomitant removal of mitochondrial death-promoting factors such as cytochrome c.

Dual-label time-resolved fluoroimmunoassay of psychopharmaceuticals and stimulants in serum

A new method to measure two different drugs simultaneously by time-resolved fluoroimmunoassay (TR-FIA) has been developed. In the TR-FIA reported here, psychopharmaceuticals [chlorpromazine (CPZ) and desipramine (DSP)] and methamphetamine (MA) contained in serum are assayed by a combined use of a new europium (Eu) chelate and a samarium (Sm) chelate, as labels. The drug concentrations were determined by the competition between a labeled antigen with Eu(3+) or biotin and a sample antigen. A microtiter plate coated with a mixture of rabbit IgGs (anti-MA and anti-CPZ or anti-MA and anti-DSP) was used. In the assay of MA and CPZ, Eu(3+) labeled MA-bovine serum albumin conjugate (MA-BSA) and biotinylated CPZ-BSA were added to the well with their non-labeled standard solutions or samples. MA was assayed by measuring the fluorescence intensity of Eu(3+) at 615 nm. After incubation of the Sm(3+) labeled streptavidin, CPZ was assayed by measuring the fluorescence of Sm(3+) at 643 nm. In the assay of MA and DSP, Eu(3+) labeled DSP-BSA and biotinylated MA-BSA were used. In our dual-assay, the minimum detection limits of these drugs were 1ng/ml for MA, 10 ng/ml for CZP and 10 ng/ml for DSP. Since the simultaneous detection of different drugs by TR-FIA is time and sample saving, the method can be employed in rapid and sensitive screening tests.

The personal identification of many samples recovered from under the sea

An automatic and rapid DNA typing system was employed for personal identification, using fragmentary tissue samples from victims in an airplane accident. Two victims were crushed into small pieces, and 33 samples suspected to belong to them were recovered from under the sea. From each sample, 10 mg was used for testing. The parents' bloods of two presumptive victims were also examined. DNA extraction from samples was performed by the NaI method, and the obtained DNA samples were analyzed with the ABI PRISM system. Among 33 samples, 31 samples were identified to be human tissues, possibly from two victims. The other two samples seemed to be parts of marine animals. ABO blood group, STR polymorphism, and mitochondrial DNA polymorphism typing were possible in every examined human sample. Two victims' fragmentary tissues were identified by determining ABO genotype, STR type and mitochondrial DNA type. The system we employed enabled an accurate typing of many fragmentary samples in a short time, thus contributing to the fast and secure identification of many victims in such cases as big air accidents.

Postoperative renal function after an abdominal aortic aneurysm repair requiring a suprarenal aortic cross-clamp

We describe herein the postoperative renal functions of patients who required a suprarenal aortic cross-clamp during abdominal aortic surgery. Seven patients required a unilateral suprarenal aortic cross-clamp (group A) and six patients required a bilateral suprarenal clamp (group B). Eighty-three patients who required an infrarenal aortic clamp were assigned to group C. Renal hypothermia with renal perfusion or topical cooling during suprarenal clamp was not performed. No hospital deaths were encountered. In group B, the postoperative creatinine and blood urea nitrogen (BUN) levels remained statistically significantly higher than that of group C until the seventh postoperative day. The postoperative renal dysfunction (serum creatinine level >2.0 mg/dl) was 28.6% in group A and 50% in group B, while it was only 8.4% in group C, although no patient required either temporary or permanent hemodialysis. The postoperative peak BUN over 30 min suprarenal clamp was significantly higher than that within 30 min. In summary, the postoperative renal function was impaired after an extended bilateral suprarenal clamp. These findings suggest that if prolonged renal ischemia is thus expected, then renal preservation should be considered.

[Aortic valve papillary fibroelastoma in a patient with mitral valve regurgitation]

Papillary fibroelastoma is a rare cardiac tumour. We describe a patient with mitral valve regurgitation and aortic valve papillary fibroelastoma. The patient was 62-year-old woman. She was referred to us for surgical treatment of mitral valve. Preoperative echocardiography showed rheumatic mitral valve regurgitation (Sellers grade III) and it also demonstrated mobile masses of the aortic valve. At operation, mitral valve was repaired by a posterior annuloplasty. Through the aortotomy, small tumors were found to be attached to each cusps of the aortic valve and they were successfully removed. The histopathologic diagnosis was papillary fibroelastoma of the aortic valve. The postoperative course was uneventful.

Detection of stimulants in hair by laser microscopy

In order to detect methamphetamine, a common stimulant, laser microscopy and immuno-histochemical staining, which uses anti-methamphetamine labeled with colloidal gold, were employed. The intensity of reflection of colloidal gold at a 488- and 514-nm line of Ar laser was measured with a laser microscope equipped with a computerized image processing system. Microtomed hair samples from five drug users who died from methamphetamine intoxication were used. The drug distribution in the hair was quite different in these five cases, but the levels of drug concentration in two different hair samples from the same abuser were correlated. The results from two hair samples with roots showed a correlation between drug concentration in hair roots and plasma samples. The proposed method needs no melanin bleaching and is simple and sensitive enough to estimate the drug concentration using only a segment of hair.

[Blood-group genotyping by constant denaturing gel electrophoresis (CDGE)]

Constant Denaturing Gel Electrophoresis (CDGE) was used as an analytical method of the genetic markers. Even a single base change in a fragment amplified by PCR was detected exactly by CDGE. The computational simulation of CDGE gave the calculation whether a single base change in a fragment amplified by PCR could be detected by CDGE or not. In this report, genotyping of three blood groups, MN, Duffy and Kidd, and Gc system is described. The regions reflecting allelic differences of each system were amplified from genomic DNAs. The concentration of denaturants (urea and formamide) in CDGE gels was decided with the computational simulation as follows: 15% for MN, 27% for Duffy, 24% for Kidd, 30% for Gc. CDGE was run in TBE buffer at 60 degrees C, 100 V constant voltage. PCR amplified fragments with 1-3 base changes were separated clearly in each gel. By staining the gels with ethidium bromide, the genotype of each system was determined. The genotyping of system by CDGE can avoid mistakes in the conventional method, which requires complicated and multiple troublesome operations. Analysis of PCR amplified fragments by CDGE will make a beneficial contribution to medico-legal practice.

[Polymorphism of hypervariable region in D-loop of mitochondrial DNA]

DNA sequences of PCR products from mitochondrial DNA (mtDNA) of 80 healthy Japanese volunteers (40 pairs, mother and child) were determined by the direct sequencing method for polymorphism. Thirty (15 pairs) of 80 samples analyzed showed a T-to-C transition at position 16189 (T16189C) of the C-stretch region in the hyper-variable region of mtDNA. For seven pairs randomly selected from the 15 T16189C pairs (C-stretch) and a single pair without the transition (non C-stretch), PCR products from the D-loop region were cloned and then sequenced. The repeat number of C in the C-stretch region was found to show heteroplasmy by sequencing multiples clones from each mtDNA. Statistical analyses of the distribution patterns of the repeat number revealed no significant differences between the mother and child in each lineage but significant differences between the lineages. The seven lineages could be then classified into four groups. The result of our data confirmed the existence of heteroplasmic polymorphism in the C-stretch region and the inheritance of the heteroplasmy from mother to child. Therefore, the analysis of heteroplasmy is applicable to individual identification.

Highly sensitive quantitation of methamphetamine by time-resolved fluoroimmunoassay using a new europium chelate as a label

A simple and highly sensitive time-resolved fluoroimmunoassay of methamphetamine (MA) using a new fluorescent europium chelate (BHHCT-Eu3+) as a label is described. Two variations of competitive immunoassay were attempted. In the first (one-step) assay, microtiter plates coated with anti-MA were used, and the new label was bound to a conjugate of bovine serum albumin and N-(4-aminobutyl)-MA (MA-BSA). In the second (two-step) assay, instead of the labeled MA-BSA, biotinylated MA-BSA and BHHCT-Eu3+-labeled streptavidin-BSA were used. The lowest measurable concentrations of MA for the one-step and the two-step methods were 1 ng/mL (25 pg/assay) and 1 pg/mL (25 fg/assay), respectively. These were 10 to 1000 times superior to the detection limits of MA in any other immunoassay. Intra-assay coefficient of variation was approximately 2-8% at eight different concentrations (n = 4). Analysis of 34 urine samples with the new method and conventional gas chromatography showed a good correlation (r = 0.954). The high detectability of the present assay also enabled segmental hair analysis with a few centimeters of a hair.

[Ruptured dissecting aneurysm of the transverse arch after replacement of the descending and ascending aorta]

A 28-year-old Marfan's syndrome woman was referred to our hospital because of sudden chest and back pain. She had received replacement of the descending and ascending aorta for acute aortic dissection previously in other two institutions. CT scan revealed the massive mediastinal hematoma and hemothorax which suggested ruptured dissecting aneurysm of the transverse arch. Emergent total arch replacement, re-ascending replacement and aortic root plasty successfully weve performed. She recovered uneventfully although she had residual thoracoabdominal dissecting aneurysm. It was suggested that total arch replacement should be performed for Stanford A type dissection in Marfan's syndrome.

[Case report of surgical repair of left ventricular free wall rupture using GRF glue and pericardial patch]

A 73-year-old woman with acute myocardial infarction (Seg. 6: 100%) was admitted to our hospital. She underwent percutaneous transluminal angioplasty (PTCA) and stent insertion to Seg. 6 on that day and anticoagulant therapy with urokinase and heparin was started in CCU. On the 4th day, chest pain developed suddenly and echocardiography revealed cardiac tamponade, so we suspected left ventricular free wall rupture. When blood pressure increased to 100 mmHg in the operating room, the left ventricular free wall rupture became "blow out" type. After establishing extracorporeal circulation, we glued Xenomedica and autologous pericardium using gelatin-resorcin-formaldehyde glue (GRF glue) to the linear tear without damaging the myocardium and coronary arteries and reducing left ventricular volume. Bleeding was completely controlled. This experience suggests that this procedure might be effective for left ventricular free wall rupture.

The apoptotic and nonapoptotic nature of the terminal differentiation of erythroid cells

The morphology of erythroid cells changes dramatically during the course of their terminal differentiation. According to calculations made with cytospin preparations obtained from Syrian hamster yolk-sac-derived erythroid cells, the area of nuclei at day 10 of gestation ranges from 25 to 85 micron 2 and is reduced to 15-25 micron 2 on day 13 [K. Morioka and R. Minamikawa-Tachino, Dev. Growth Differ. 35, 569-582, 1993]. The DNA and protein contents of each nucleus also decrease during this period. Nonspecific fragmentation of DNA was detected by agarose gel electrophoresis in all samples obtained from day 10 to day 13 of gestation, while distinct ladders of DNA fragments were not detected. DNA fragmentation was also detected by an in situ DNA-end labeling (TUNEL) assay. As the terminal differentiation proceeded, gradual decreases in levels of both histone H1 and most nonhistone proteins were observed by SDS-polyacrylamide gel electrophoresis, while levels of core histones appeared to be constant. In particular, lamin B2 was almost completely lost from the nuclear matrix fraction on day 11. These results suggest that the terminal differentiation of erythroid cells and apoptosis might have common mechanisms. However, expansion of the cytoplasm during the terminal differentiation distinguishes these processes. In addition, in the erythroid terminal differentiation, nuclei never form lobules or become fragmented; no apoptotic bodies are formed, occurrence of the apoptosis-like cellular change is not sporadic but rather synchronous, and the process is slow, with at least several days being required for cell death. These characteristics are different from those of typical apoptosis. Thus, the terminal differentiation of nucleated embryonic erythroid cells exhibits both apoptotic and nonapoptotic features.

Detection of bathsalts in the lungs of a baby drowned in a bathtub: a case report

This case is one in which a baby was found dead, apparently drowned in a bathtub. To confirm the inhalation of bathwater, an extract taken from the baby's lungs was analyzed with high-performance liquid chromatography. Bathsalts contained in the bathwater were detected in the extract. Bathsalts are usually used in home bathtubs and, as a dye material, they contain fluorescein which is highly sensitive to detection. The presence of fluorescein in the lung tissue and in the other tissues greatly helps to confirm the bathwater drowning.

[Three cases of right-sided active endocarditis with multiple pulmonary infarction]

We have experienced three patients with right-sided active endocarditis combined with multiple pulmonary infarction. Ventricular septal defect (VSD), aortic regurgitation (AR), tricuspid regurgitation (TR) and congestive heart failure were present in case 1. TR was present in case 2. VSD, TR and patent ductus arteriosus were present in case 3. alpha-Streptococcus caused endocarditis in case 1 and 3; Candida albicans caused endocarditis in case 2. Antibotic therapy had no effect in case 2 and 3. Case 1 and 3 developed pulmonary hemorrhage, which resolved before the operation in case 1, but not in case 3. Our three patients underwent surgery and recovered successfully. They were discharged on the 43th, 58th and 32th postoperative day and are presently free of clinical symptoms. These experiences suggest surgery should be undertaken in the following situations: 1. antibiotic therapy has no effect on the infection, 2. hemodynamics are worsening, and 3, pulmonary infarction and pulmonary hemorrhage occur repeatedly.

[The waffle procedure (multiple incision of epicardium) with pericardiectomy for constrictive pericarditis]

Pericardiectomy is the only effective surgical procedure for constrictive pericarditis, but we have often experienced a lack of significant improvement of hemodynamic parameters, this being attributed to the presence of residual constriction. We have had two patients with constrictive pericarditis. In these patients, we decorticated the pericardium as usual, anterior to the bilateral phrenic nerves without cardiopulmonary bypass, and then, multiple longitudinal and transverse incisions were carefully made in the fibrous epicardium, avoiding the predicted course of major coronary branches and the myocardium. At the end of the procedure, the epicardial fibrous surface acquired a waffle-like appearance. With this maneuver, relief of constriction was achieved and the myocardium was able to reexpand, thus obtaining an adequate hemodynamic response. Our two patients recovered fully, and were discharged on the 18th and 19th postoperative day. They are presently free of clinical symptoms.

[Two-staged repair of coarctation of the aortic arch with severe subaortic stenosis and ventricular septal defect]

Aortic arch coarctation proximal to the left subclavian artery is a rare anomaly. It is about 1% of all coarctation of the aorta. This 16 days neonate with coarctation of aortic arch with severe subaortic stenosis and ventricular septal defect was underwent two staged repair. In the first-stage operation, coarctation of the aortic arch was reconstructed by extended end to end direct anastomosis through posterolateral thoracotomy. In the second stage, we performed intracardiac repair with use of a technique which included resection of superior margin of conus septum through VSD and patch closure of VSD. The postoperative pressure study showed no gradient between left ventricle and left radial artery. The postoperative course was satisfactory. This patient is doing well.

[A successful surgical case report of acute aortic dissection involving entire sinus of Valsalva]

We successfully performed aortic root replacement for acute aortic dissection, Stanford type A involving the entire sinus of Valsalva, associated with acute anterior wall myocardial infarction and aortic valve insufficiency. A 57-year-old man was admitted complaining of chest pain. An emergency operation was performed after a perfusion catheter was inserted to 99% stenotic lesion of the left anterior descending artery (LAD) on the same day. The dissection extended to both ostia of the coronary arteries and disrupted all commissures of the aortic valve, resulting in severe prolapse of the aortic valve leaflets. Aortic root replacement was performed using a valved conduit. The left main coronary artery was reattached to the graft using interposition technique with a 8 mm diameter woven Dacron tube graft. In addition, the LAD and right coronary artery were bypassed using saphenous vein. The postoperative course was uneventful and the patient was discharged from hospital on the 35th postoperative day. Retaining no aortic sinus and adequate coronary artery reconstruction is important for surgical repair of aortic dissection involving the entire sinus portion of the ascending aorta.

A murine neural-specific homolog corrects cholinergic defects in Caenorhabditis elegans unc-18 mutants

Caenorhabditis elegans UNC-18 protein, homologous to yeast Sec1p, is important in neurotransmitter release, because the unc-18 mutation leads to severe paralysis and presynaptic acetylcholine (ACh) accumulation. To examine the functional conservation in mammals, we tried to isolate unc-18 isoforms from mouse and human brain cDNA libraries and obtained two classes of isoforms-neural genes and ubiquitous genes. Neural genes were identical to Munc-18 (also known as n-Sec1 or rbSec1), identified in rat and bovine brains as a syntaxin-binding protein. According to "Munc-18" terminology, we call the neural genes Munc-18-1 and the ubiquitous genes Munc-18-3. These mammalian isoforms exhibit 58% (Munc-18-1) and 42-43% (Munc-18-3) amino acid sequence identity with UNC-18. Next, we constructed transgenic unc-18 mutants to test biological activity of mouse Munc-18-1 and Munc-18-3 under the control of C. elegans unc-18 promoter. Munc-18-1 compensates for severe locomotion disability and cholinergic defects, e.g., abnormal sensitivities to cholinesterase inhibitors and cholinergic receptor agonists in unc-18 mutants, but Munc-18-3 fails. These data suggest that Munc-18-1 and C. elegans unc-18 may play positive roles in ACh release and that the molecular mechanism of neuronal regulated secretion has been partially conserved from nematodes to mammals.

Quantitation of tobramycin concentration by laser microscopy in an epithelial cell of renal tubule

To estimate tobramycin concentration in an epithelial cell of renal tubule without pulverizing or extracting it, we used immunohistochemical straining, using antibody coated colloidal gold. The intensity of reflection of colloidal gold at 514nm was measured with a laser microscope. Colloidal gold, reacted with tobramycin, was determined as having a gray scale on the microscopic image. This method was useful and sensitive enough to know the local concentrations of drug and/or other chemical substances.

[A case report of total cavopulmonary connection following total cavopulmonary shunt]

A 20-year-old man underwent total cavopulmonary shunt for univentricular heart type A (A.L.L.) with hemiazygos connection six years ago. Four years later, his condition deteriorated with easy fatigue and cyanosis. Cardiac catheterization showed recanalization of ligated SVC. Chest CT showed tight adhesion between the chest wall and the ascending aorta. We approached the heart through left anterolateral thoracotomy in order to avoid injury of the aorta and the ventricle during redo median sternotomy. Total cavopulmonary connection with intraatrial conduit was performed under circulatory arrest and retrograde cardioplegia without aortic cross clamp. His postoperative course was satisfactory. Left thoracotomy was useful for total cavopulmonary connection following total cavopulmonary shunt associated with postoperative adhesion.

Stimulation of TIMP-1 production by oncostatin M in human articular cartilage

OBJECTIVE

To investigate the effects of the interleukin-6 (IL-6) family cytokines, such as IL-6, IL-11, leukemia inhibitory factor (LIF), and oncostatin M (OSM), on the production of tissue inhibitor of matrix metalloproteinases 1 (TIMP-1) in human articular cartilage.

METHODS

Effects of IL-6 family cytokines and growth factors on TIMP-1 production were studied in human articular chondrocytes, grown as monolayer and cartilage explant culture. TIMP-1 protein levels in the cultured medium were measured by sandwich enzyme immunoassay. TIMP-1 messenger RNA levels in the cultured chondrocytes were analyzed by Northern blotting. Western blot analysis was performed to evaluate the release of matrix metalloproteinases (MMPs) in the cultured medium. Cell proliferation of chondrocytes was determined by 3H-thymidine uptake.

RESULTS

IL-6 family cytokines induced TIMP-1 expression in monolayer and explant culture, and the production of TIMP-1 was most stimulated by OSM. In contrast, OSM did not modulate the release of MMPs and cell proliferation.

CONCLUSION

These results suggest that OSM may be characterized as one of the chondroprotective mediators in cartilage destruction.

Distribution of actin, myosin, and spectrin during enucleation in erythroid cells of hamster embryo

Yolk-sac derived erythroblasts undergo semi-synchronous maturation and some of them enucleate in the peripheral blood of embryos. We have studied the assembly and distribution of actin, myosin, and spectrin during the enucleation of Syrian hamster embryonic erythroblasts. At day 11 of the gestation, that is just before the start of the enucleation, formation of a cytoskeletal structure consisted chiefly of particulate associations of F(filamentous)-actin was detected by the staining with rhodamine-labeled phalloidin. Stress-fiber-like structures were not observed in each differentiation stage after day 10. Distribution of myosin, actin, and spectrin was studied immunocytochemically to know the role of them in the enucleation of erythroid cells that starts at late day 11 or early day 12 in the gestation. The enucleation is preceded by the approach and the subsequent attachment of nucleus to the plasma membrane. At that time, actin and myosin are present in the cytoplasmic and cortical region of the cells. From the time when the extrusion of nucleus has started, condensation of actin and myosin was observed at the cell cortex area surrounding the extruding nucleus, and a contractile ring-like structure was infrequently observed. Spectrin was observed in the cortical region of the cells, and the change of the localization of spectrin was not observed throughout the terminal differentiation process (days 10-12) of the embryonic erythroid cells. The results show the possible involvement of a myosin-actin contractile system that appears around the extruding nucleus within the mechanism of erythroid enucleation.

[Limulus test (factor G pathway) positive substance during cardiopulmonary bypass]

Limulus cascade reaction is found to be frequently activated by the plasma in the patients undergoing cardiopulmonary bypass (CPB). Recently, it is considered that this phenomenon occurs by factor G pathway reactive activity (GPRA) rather than endotoxin that activates factor C pathway. In the present report, we investigated circulating endotoxin and GPRA in 32 patients undergoing CPB. Plasma was pretreated by the New PCA method, and assay was performed by two limulus tests; Toxicolor (reactive with endotoxin and GPRA) and Endospecy (endotoxin-specific). Thirty-two patients were classified into four groups by clinical diagnosis, Group A; dissecting aneurysm of the aorta (6 patients), Group B; ischemic heart disease (9 patients), Group C; heart valve disease (8 patients), Group D; congenital heart disease and myxoma in left atrium (9 patients). GPRA in Ringer's lactate hardly increased during previous circulation before operation. The highest plasma GPRA concentration in all patients was observed at the end of CPB, 415 +/- 342pg/ml, but plasma endotoxin concentration was within normal range. At the end of CPB, plasma GPRA concentrations were 761 +/- 180pg/ml in Group A, 646 +/- 341pg/ml in Group B, 230 +/- 86pg/ml in Group C, and 113 +/- 65pg/ml in Group D. GPRA increase ratio (GPRA increase value/CPB time) of Groups A and B was significantly higher (p < 0.05) than that of Groups C and D. It was suggested that the origin of plasma GPRA during CPB was not the CPB circuit but the tissue of the patients.