Structure and bonding of water on Pt(111)

We address the adsorption of water on Pt(111) using x-ray absorption, x-ray emission, and x-ray photoelectron spectroscopy along with calculations in the framework of density functional theory. Using the direct relationship between the electronic structure and adsorbate geometry, we show that in the first layer all the molecules bind directly to the surface and to each other through the in-layer H bonds without dissociation, creating a nearly flat overlayer. The water molecules are adsorbed through alternating metal-oxygen (M-O) and metal-hydrogen (M-HO) bonds.

Lessons from similarities between SLE and HIV infection

OBJECTIVE

We attempted to obtain deeper understanding of systemic lupus erythematosus (SLE) and human immunodeficiency virus (HIV) infection through comparative studies between both diseases.

METHOD

For this purpose, we reviewed and discussed lessons from similarities in both diseases based on our own and reported findings in literatures.

RESULT

Such comparative studies may contribute to the progress in understanding the clinical or pathogenetic features of these diseases.

CONCLUSION

Further studies into the relationship between SLE and HIV infection may bring to light important clues to assist in the development of better treatments for each disease.

Effects of nucleotides on N-acetyl-d-glucosamine 2-epimerases (renin-binding proteins): comparative biochemical studies

Renin-binding protein (RnBP) is an endogenous renin inhibitor originally isolated from porcine kidney as a complex of renin, so-called high molecular weight (HMW) renin. Our recent studies demonstrated that human RnBP is the enzyme N-acetyl-D-glucosamine (GlcNAc) 2-epimerase [Takahashi, S. et al. (1999) J. Biochem. 125, 348-353]. We have purified recombinant human, rat, and porcine RnBPs expressed in Escherichia coli JM 109 cells. The purified recombinant RnBPs existed as dimers and inhibited porcine renin activity strongly. On the other hand, porcine renin inhibited recombinant GlcNAc 2-epimerase activities. The human GlcNAc 2-epimerase activity could not be detected in the absence of a nucleotide, whereas ATP, dATP, ddATP, ADP, and GTP enhanced the human GlcNAc 2-epimerase activity. Other nucleotides had no effect on human GlcNAc 2-epimerase activity. Rat and porcine GlcNAc 2-epimerases were activated by several nucleotides. Nucleotides that enhance the activity of GlcNAc 2-epimerases protect these enzymes against degradation by thermolysin. These results indicate that mammalian RnBPs have GlcNAc 2-epimerase activity and that nucleotides are essential for formation of the catalytic domain of the enzyme.

Eccentric exercise-induced morphological changes in the membrane systems involved in excitation-contraction coupling in rat skeletal muscle

1. Physiological evidence suggests that excitation-contraction (E-C) coupling failure results from eccentric contraction-induced muscle injury because of structural and morphological damage to membrane systems directly associated with the E-C coupling processes within skeletal muscle fibres. In this study using rats, we observed the ultrastructural features of the membrane systems of fast-twitch (FT) and slow-twitch (ST) muscle fibres involved in E-C coupling following level and downhill running exercise. Our aim was to find out whether mechanically mediated events following eccentric exercise caused disorder in the membrane systems involved in E-C coupling, and how soon after exercise such disorder occurred. We also compared the morphological changes of the membrane systems between ST and FT muscle fibres within the same muscles. 2. Single muscle fibres were dissected from triceps brachii muscles of male Fischer 344 rats after level or downhill (16 deg decline) motor-driven treadmill running (18 m min(-1), 5 min running with 2 min rest interval, 18 bouts). All single muscle fibres were histochemically classified into ST or FT fibres. The membrane systems were visualized using Ca(2+)-K(3)Fe(CN)(6)-OsO(4) techniques, and observed by high voltage electron microscopy (120-200 kV). 3. There were four obvious ultrastructural changes in the arrangement of the transverse (t)-tubules and the disposition of triads after the downhill running exercise: (1) an increase in the number of longitudinal segments of the t-tubule network, (2) changes in the direction and disposition of triads, (3) the appearance of caveolar clusters, and (4) the appearance of pentads and heptads (close apposition of two or three t-tubule elements with three or four elements of terminal cisternae of the sarcoplasmic reticulum). The caveolar clusters appeared almost exclusively in the ST fibres immediately after downhill running exercise and again 16 h later. The pentads and heptads appeared almost exclusively in the FT fibres, and their numbers increased dramatically 2-3 days after the downhill running exercise. 4. The eccentric exercise led to the formation of abnormal membrane systems involved in E-C coupling processes. These systems have unique morphological features, which differ between ST and FT fibres, even within the same skeletal muscle, and the damage appears to be concentrated in the FT fibres. These observations also support the idea that eccentric exercise- induced E-C coupling failure is due to physical and chemical disruption of the membrane systems involved in the E-C coupling process in skeletal muscle.

Remote verification in radiotherapy using digitally reconstructed radiography (DRR) and portal images: a pilot study

PURPOSE

To use digitally reconstructed radiography (DRR) and digitally compressed portal images in distant consultation using a telecommunications network, the verification performance of DRR and digitally compressed portal images on the image console was investigated.

METHODS AND MATERIALS

A human thoracic phantom was scanned with computed tomography (CT). Radiotherapy was planned at 5 different anatomic locations. A digitally reconstructed radiograph was made; verification films of the phantom were then taken with 6-MV X-rays. The treatment center was intentionally dislocated. Fifty sets of DRR and portal images were seen by 7 doctors on a conventional view-box (view-box method) to judge whether the treatment center was dislocated. These image sets were digitalized by a film scanner, compressed to 1/10 Joint Photographic Experts Group (JPEG) format, and compared on an image console by the same physicians (image-console method). The verification performance of the image console method was compared with that of the view-box method by means of receiver operating characteristic (ROC) analysis. Clinically, 159 portal-image-sets were verified with the image-console method and the appropriateness of the decision was later assessed by the view-box method.

RESULTS

The accuracy of the treatment verification was estimated to be 88.8% by the conventional view-box method and 88.3% by the image-console method. There was no statistically significant difference in the verification performances of the conventional method (Az = 0.86+/-0.02) and the image console method (Az = 0.84+/-0.07). Frequent digital image-processing modification was positively related to the accuracy of verification. Clinically, there were 3 (1.8%) major corrections, 31 (19.5%) minor corrections, and 123 cases with no correction. No further correction was called for by the re-evaluation using the view-box method.

CONCLUSION

The verification performance of DRR and digitally compressed portal images on the image console was as accurate as the conventional method. Distant consultation using DRR and portal images through telecommunication is usable in clinical practice.

Interesting RI accumulation in hepatic images with Tc-99m GSA SPECT scintigraphy in idiopathic portal hypertension

The authors report a case of idiopathic portal hypertension (IPH), which showed interesting RI accumulation on Single Photon Emission CT (SPECT) images, with Tc-99m galactosyl human serum albumin (GSA) scintigraphy. Accumulation of Tc-99m GSA was decreased in the periphery of the liver where strong enhancement was revealed only in the arterial phase on dynamic CT. These findings imply that portal flow is decreased in the periphery of the liver where arterial flow is dominant. It was thought that secondary reduced activity of GSA due to a decrease in portal flow results in reduced radioactivity in the periphery of the liver in IPH. This interesting accumulation of Tc-99m GSA may be one of the sign of IPH.

Collaborative work to evaluate toxicity on male reproductive organs by repeated dose studies in rats 21). Comparison of the effects of 2- and 4-weeks pyrimethamine treatment in rats

Pyrimethamine (PYR), clinically used as an antimalarial or antiparasitic agent, is known to exert testicular toxicity in rats on oral administration for 8 weeks. This study was performed to examine whether 2-weeks daily repeated doses of PYR might induce detectable toxicity on the male reproductive organs in rats. PYR was orally administered to Slc:SD male rats at doses of 12.5, 25 or 50 mg/kg for 2 weeks, or 6.25, 12.5 or 25 mg/kg for 4 weeks. No effects were seen in any group on physical examination and body weight measurement. Gross findings in autopsy exhibited no abnormalities in any of the animals. There were no meaningful changes in the weights of reproductive organs, or in the number and activity of sperm in the epididymides. Loss and degenerative changes of pachytene spermatocytes in stages I to III seminiferous tubules were observed in the rats given 50 mg/kg PYR for 2 weeks. From the results obtained, it is concluded that 2-weeks repeated dosing with PYR is sufficient to detect toxicity on male reproductive organs in rats using histopathological examination.

Induction of pancreatic islet cell tumors in rats by repeated intravenous administration of 4-hydroxyaminoquinoline 1-oxide

The inducibility of pancreatic islet cell tumors by administration of 4-hydroxyaminoquinoline 1-oxide (4HAQO) was investigated in male 6-week-old Sprague-Dawley rats. Rats were given 4HAQO intravenously at a weekly dose of 5 mg/kg 4 times (group 1) or a single dose of 10 mg/kg (group 2). Control rats received the vehicle alone (group 3). Fifty-six weeks after the first 4HAQO administration, all surviving animals were killed and the pancreas was examined histopathologically, immunohistochemically and ultrastructurally. The incidences and multiplicities of islet cell tumors in groups 1, 2, and 3 were 52.3% (p < 0.05 vs group 2, p < 0.01 vs group 3), 19.2% and 0%, and 0.70/animal (p < 0.05 vs group 2, p < 0.01 vs group 3), 0.23 and 0, respectively. Islet cell carcinomas were induced only in group 1, accounting for 6/44 (26%) tumors. Islet cell hyperplasias were found in 61.4% (p < 0.05 vs group 3), 42.3% and 10.0% of groups 1, 2, and 3, with multiplicities of 0.95 (p < 0.05 vs groups 2 and 3), 0.54 and 0.20, respectively. As compared with normal islets from control subjects, islet cell tumors showed an increase in the number of insulin positive cells associated with cytological features indicative of enhanced insulin synthesis and secretion, and a decrease in the number of glucagon positive cells without ultrastructural signs of modified secretory activity. Thus our results indicate that repeated intravenous administration of 4HAQO to rats is useful for the induction of islet cell tumors at high incidence.

A possible pathogenic role of CD8+ T cells and their derived cytokine, IL-16, in SLE

Current investigations into the role of CD8+ T cells and their derived cytokine, interleukin (IL)-16, in the induction of CD4+ T cell abnormalities in systemic lupus erythematosus (SLE) were reviewed and discussed on the basis of results mainly obtained in our laboratory.

Sequence analysis of human endogenous retrovirus clone 4-1 in systemic lupus erythematosus

Human endogenous retroviruses (HERV) have emerged as a possible cause of systemic lupus erythematosus (SLE). We previously detected serum antibodies to the gag region of HERV clone 4-1 in patients with SLE, but not in normal volunteers. In the present study, we detected clone 4-1 messenger RNA (mRNA) in peripheral blood mononuclear cells (PBMC) from SLE patients and performed sequence analysis of the cDNA or genomic DNA from clone 4-1 in these patients. Clone 4-1 mRNA was detected in all of the SLE patients tested, although it was not found in normal controls. Sequence analysis of clone 4-1 in these SLE patients revealed inactivation of the stop codons in part of the gag region. In addition, a computer search of current sequence libraries revealed that the clone 4-1 gag genomic DNA from SLE patients was more highly homologous with the clone 4-1 sequence in chromosome 11 from normal individuals when compared with the sequence of clone 4-1 integrated in the other chromosomes. It is possible that transcription of clone 4-1 from chromosome 11 occurs in SLE, and that the stop codon inactivation contributes to the translation of clone 4-1 gag proteins in patients with this disease.

Identification of functionally important cysteine residues of the human renin-binding protein as the enzyme N-acetyl-D-glucosamine 2-epimerase

Renin-binding protein (RnBP) is an endogenous renin inhibitor originally isolated from porcine kidney. It was recently identified as the enzyme N-acetyl-D-glucosamine (GlcNAc) 2-epimerase [Takahashi, S. et al. (1999) J. Biochem. 125, 348-353] and its active site residue was determined to be cysteine 380 by site-directed mutagenesis [Takahashi, S. et al. (1999) J. Biochem. 126, 639-642]. To further investigate the relationship between structure and function of recombinant human (rh) RnBP as a GlcNAc 2-epimerase, we have constructed several C-terminal deletion and multi-cysteine/serine mutants of rhGlcNAc 2-epimerase and expressed them in Escherichia coli cells. The expression was detected by Western blotting using anti-rhRnBP antiserum. The C-terminal deletion mutant, Delta400-417, had approximately 50% activity relative to the wild-type enzyme, but other C-terminal deletion mutants, Delta380-417, Delta386-417, and Delta390-417, had no enzymatic activity. Mutational analysis of multi-cysteine/serine mutants revealed that cysteines 41 and 390 were critical for the activity or stabilization of the enzyme, while cysteine residues in the middle of the enzyme, cysteines 125, 210, 239, and 302, had no essential function in relation to the activity.

[Lower-end sternal splitting (LESS) approach as a new strategy for minimally invasive off-pump CABG]

There are several ways to perform off-pump coronary artery bypass grafting (OPCAB) using a minimally invasive method. Currently, one of the most commonly used approaches is left anterior small thoracotomy (LAST). However, using this approach, only the LAD can be grafted. We have employed a partial sternotomy without a transverse cut, namely, the lower-end sternal splitting (LESS) approach for OPCAB. Through this approach, the LAD and RCA can be revascularized via a single small incision without the risk of damaging the tissue around the intercostal space when the sternum is transversely divided. Since November 1999 to September 2000, we have applied OPCAB through LESS approach in 17 patients. Mean age was 70.0 + 5.4 years (range 58-77), and 13 were men. Mean length of the skin incision was 8.6 + 1.2 cm (range 8-11). No hospital death or morbidity was observed. No patient required blood transfusion. All had arterial conduits: LITA-LAD, in 11; LITA-LAD, RITA-RCA, in 1; LITA-LAD, GEA-PDA, in 2; LITA-LAD, RITA-RCA, RITA-RA-PDA, in 1; and GEA-PDA, in 2. All underwent postoperative coronary angiography, and the patency rate was 95.5%. Our experience demonstrates that the LESS approach for OPCAB is technically feasible and can be used with excellent cosmetic results and safety. Although experience is limited, this less invasive surgical technique can be used as an alternative approach for MIDCAB in patients with LAD and/or RCA disease.

Magnetic circular dichroism of resonant X-ray emission spectra at L edges of rare-earth compounds

We study the resonant x-ray emission spectroscopy (RXES) and the magnetic circular dichroism (MCD) at the L2,3 absorption edges of rare-earth elements, especially gadolinium ion. To this end, an atomic model is adopted and the multiplet coupling effect is taken into account. Using the formula of the coherent second order optical process which consists of the excitation process from the 2p core state to the empty 5d state and of the radiative decay from the 3d core state to the 2p core hole, we calculate RXES-MCD spectra. By inspection, we have confirmed that the enhancement of the 2p-5d dipole matrix element proposed for MCD of x-ray absorption spectroscopy. In addition, characteristic features of the spectra observed in gadolinium metallic compounds are reproduced by our calculations.

Quantitative analyses of messenger RNA of human endogenous retrovirus in patients with systemic lupus erythematosus

OBJECTIVE

Human endogenous retrovirus (HERV) has emerged as a possible causative agent of systemic lupus erythematosus (SLE). To investigate the role of HERV in the etiology of SLE, we performed quantitative analyses of messenger RNA (mRNA) of the HERV clone 4-1 in patients with SLE.

METHODS

Reverse transcriptase (RT)-polymerase chain reaction (PCR) and real-time quantitative PCR (RQ-PCR; TaqMan methodology) were used in this experiment.

RESULTS

The quantities of mRNA of the HERV clone 4-1 gag region in patients with SLE were significantly higher than in healthy controls, and the amounts of such mRNA in the patients were decreased by steroid treatment.

CONCLUSION

These phenomena may be related to the production of viral components derived from HERV clone 4-1 and contribute to the pathogenesis of SLE; studies using a larger number of patients are required to confirm these points.

Calculation of rare-earth 4d giant-absorption spectra with multiplet effects and decay processes

The total and partial photoelectron yield spectra of all the trivalent rare-earth ions in the 4d giant resonance region are calculated with full multiplet effects. The decay processes are treated as coherent processes following photoexcitation. The results reproduce the over all features of experiments. It is obtained that the character of the giant-absorption is different between the light and heavy rare-earths. The multiplet effects play an essential role in the decay processes.

Electronic structure effects from hydrogen bonding in the liquid phase and in chemisorption: an integrated theory and experimental effort

A closely integrated theoretical and experimental effort to understand chemical bonding using X-ray spectroscopic probes is presented. Theoretical techniques to simulate XAS (X-ray absorption spectroscopy), XES (X-ray emission spectroscopy), RIXS (resonant inelastic X-ray scattering) and XPS (X-ray photoelectron spectroscopy) spectra have been developed and implemented within a density functional theory (DFT) framework. In combination with new experimental techniques, such as high-resolution XAS on liquid water under ambient conditions and XES on complicated surface adsorbates, new insight into e.g. hydrogen-bonded systems is obtained. For the (3x2) overlayer structure of glycine/Cu(110), earlier work has been extended to include adsorbate-adsorbate interactions. Structures are optimized for large cluster models and for periodic boundary conditions. It is found that specific features in the spectra arise from hydrogen-bonding interactions, which thus have important effects at the molecular-orbital level. XAS on liquid water shows a pronounced pre-edge feature with significant intensity, while the spectrum of ice shows only little intensity in this region. Theoretical spectrum calculations, based on instantaneous structures obtained from molecular-dynamics (MD) simulations, show that the pre-edge feature in the liquid is caused by water molecules with unsaturated hydrogen bonding. Some aspects of the theoretical simulations will be briefly discussed.

Retroviruses and autoimmunity

The investigation of human retroviruses has shown dramatic progress since the discovery of human immunodeficiency virus (HIV). These studies have also contributed to the exploration of the role of retroviruses, including endogenous retroviruses, in the induction of autoimmune diseases such as systemic lupus erythematosus (SLE). This review describes the potential role of retroviruses in autoimmunity, based on recent findings including our own results.

Serial change in the atrial transport function after the radial incision approach

BACKGROUND

The left atrial transport function recovers slowly over several months after the maze procedure (Maze), but remains at a low level even during the long-term postoperative period. Because the Maze leaves an insufficient left atrial transport function, patients may still be prone to thromboembolism after the Maze. The radial incision approach (Radial) has been shown to preserve greater atrial transport function than does the Maze in the early postoperative period.

METHODS

To examine the serial change in the atrial transport function after the Radial, out of 32 patients who underwent the Radial, 15 patients were assessed by transthoracic Doppler echocardiography 1, 3, 6, and 12 months after surgery. The atrial filling fraction and peak A/E velocity ratio were determined from the flow-velocity spectra across the mitral and tricuspid valves. The incidence of thromboembolic events was examined in 21 patients who were followed for more than 3 months after the Radial. The data were compared with data obtained from 13 patients after (41 +/- 6 months) the Maze III procedure.

RESULTS

The left atrial transport function after the Radial increased within 3 months to a significantly greater level than did that after the Maze in the longterm. The atrial filling fraction was 28.2% +/- 7.9% at 3 months after the Radial and 15.1% +/- 4.0% at 41 months after the Maze (p < 0.01). The peak A/E ratio was 0.52 +/- 0.18 at 3 months after the Radial and 0.25 +/- 0.07 at 41 months after the Maze (p < 0.01). This increased atrial transport function was maintained for an extended period after the Radial. There were no thromboembolic events in any of the patients after the Radial or Maze, irrespective of postoperative anticoagulant therapy.

CONCLUSIONS

The Radial approach prevents thromboembolism by restoring sufficient atrial transport function more effectively and faster than does the Maze.

Non-Hodgkin's malignant lymphoma of the sinonasal tract--treatment outcome for 53 patients according to REAL classification

OBJECTIVE

Although the Working Formulation is commonly used to classify NHL in Japan, it has been recognized as imperfect for primary extranodal lymphoma, especially for patients with sinonasal disease because of their histological characteristics. The present study investigated the clinical characteristics and the prognosis of sinonasal lymphomas according to REAL classification.

METHODS

Fifty-three patients with non-Hodgkin's malignant lymphoma (NHL) of the sinonasal tract were treated between 1981 and 1997. The age at clinical presentation was from 10 to 84 years (mean, 52.4 years). According to the Ann Arbor system, there were 30 patients with Stage IE, 13 with Stage IIE, 4 with Stage IIIE, and 6 with Stage IVE lymphomas. Twenty-two patients (41.5%) had B symptoms. The primary sites were the nasal cavity (67.8%), maxillary sinus (20.8%), ethmoidal sinus (9.4%), and frontal sinus (1.9%). The survival data was calculated by Kaplan-Meier method. Statistical analysis was performed with a generalized Wilcoxon method.

RESULTS

All of the lymphomas showed a diffuse growth pattern. Based on the origin of the tumor cells, the authors classified NHL of the sinonasal tract into five groups with the REAL classification of Japan: diffuse large B-cell lymphoma (22.6%), peripheral T-cell lymphomas (15.1%), angiocentric lymphoma (35.9%), other lymphomas and unclassified types. Of 53 patients, 39 (73.6%) received chemotherapy and radiotherapy, eight patients received chemotherapy alone, and four patients received radiotherapy alone. The cumulative 5-year survival rates were 28.5% for all of the types, 55.0% for diffuse large B-cell lymphoma, 33.3% for peripheral T-cell lymphoma, and 19.7% for angiocentric lymphoma. Results suggest that conventional combined treatment (CHOP chemotherapy+radiotherapy) is ineffective for NHL of the sinonasal tract, and especially so for NHL in the nasal cavity, NHL with tumor cells with positive T-cell markers, NHL further than Stage IIE and NHL with B symptoms.

CONCLUSION

(1) In light of this ineffectiveness, new therapies must be developed to improve patient outcome instead of the conventional combined treatment; (2) REAL classification is clear and useful for sinonasal lymphomas in Japan.