Chemotactic responses of osteoblastic MC3T3-E1 cells toward zinc chloride

Although zinc (Zn) is known to participate in bone formation, its exact role in the remodeling of this tissue has not been fully clarified. The present study was designed to investigate whether Zn has a role at the resorptive sites in vitro. We investigated the migration of osteoblastic MC3T3-E1 cells in response to Zn using a Boyden chamber assay. Exposure of MC3T3-E1 cells to Zn stimulated the migration of MC3T3-E1 cells. Checkerboard analysis revealed that the migration of MC3T3-E1 cells toward Zn was a directional (chemotaxis) rather than a random (chemokinesis) motion. Pretreatment of MC3T3-E1 cells with pertussis toxin completely blocked the chemotactic response of cells to Zn, indicating that it is mediated by G-protein-coupled receptors. Because the bone is one of the major Zn storage sites, we suggest that Zn released from bone-resorptive sites plays an important role in the recruitment of osteoblasts and bone renewal.

Localization of zinc after in vitro mineralization in osteoblastic cells

The present study was designed to investigate the incorporation of zinc (Zn) into cultured UMR-106 osteoblasts in response to mineralization caused by the addition of beta-glycerophosphate. As a result of the induced mineralization, the contents of calcium (Ca), phosphorus (P), and Zn in the monolayer increased, whereas the magnesium (Mg) content did not change. The activity of alkaline phosphatase (ALP) also increased during the process. The zinc distribution in the cell monolayer was studied using Zinquin, a fluorescent zinc ion chelator. The double fluorescent labeling with Zinquin and calcein revealed that zinc was localized both as intracellular vesicles and extracellular clusters, whereas calcium was colocalized with extracellular zinc. These results suggest that zinc is involved in the mineralization process of UMR-106 cells.

Macrophage accumulation associated with rat cardiac allograft rejection detected by magnetic resonance imaging with ultrasmall superparamagnetic iron oxide particles

BACKGROUND

Acute cardiac allograft rejection continues to be the cause of graft loss and contributes to the morbidity and mortality after cardiac transplantation. In this study, we report a new method for detecting organ rejection in transplantation with an MR-based technique using dextran-coated ultrasmall superparamagnetic iron oxide (USPIO) particles. These particles ( approximately 27 nm in diameter) are known to shorten relaxation times in MRI experiments.

METHODS AND RESULTS

A new rat model of heterotopic heart and lung transplantation has been developed for MRI experiments. Allotransplantations (DA-->BN) were performed (n=8), with syngeneic transplantations (BN-->BN) serving as controls (n=8). MR images were obtained with a gradient echo method. At postoperative day 7, allotransplants developed moderate rejection as determined histopathologically. A significant reduction in MR signal intensity was observed after USPIO injection into rats with allotransplanted hearts. Syngeneic transplants showed no differences in MR signal intensity before and after USPIO injections. After injection of USPIO particles at postoperative day 6, a group of allotransplanted rats was treated with cyclosporin A (3 mg/kg). Animals treated with cyclosporin A for 7 days showed no reduction in MR signal intensity after USPIO reinjection at day 14, whereas animals treated for 4 days showed a significant decrease in MR signal intensity in the transplanted hearts indicative of acute graft rejection. Pathological analysis of these animals revealed that dextran-coated USPIO particles were taken up by the infiltrating macrophages that accumulated within the rejecting cardiac graft.

CONCLUSIONS

This MRI method offers promise as a noninvasive method for detecting transplant allograft rejection.

Angiotensin-converting enzyme inhibitor preserves p21 and endothelial nitric oxide synthase expression in monocrotaline-induced pulmonary arterial hypertension in rats

BACKGROUND

Pulmonary arterial hypertension (PAH) is associated with structural changes in the pulmonary vasculature characterized by the proliferation of cellular components of the vessels. ACE inhibitor (ACEI) may have beneficial effects in treating PAH, but its precise mechanism of action in the remodeling process is unclear. p21 is a cyclin-dependent kinase inhibitor that may have a protective role in this process by inhibiting cellular proliferation. Endothelial nitric oxide synthase (eNOS) has also been shown to be protective by its vasodilatory effect. Therefore, we investigated whether expression of p21 and eNOS was modulated by ACEI treatment in a rat model.

METHODS AND RESULTS

Monocrotaline (MCT) was administered to 2 groups of Sprague-Dawley rats fed a high-cholesterol diet, ie, one group received MCT concomitantly with enalapril treatment (MCT(+)/ACEI(+) rats), and the other group did not receive enalapril (MCT(+)/ACEI(-) rats). After 5 weeks, MRI showed right ventricular hypertrophy in MCT(+)/ACEI(-) rats. MCT(+)/ACEI(+) rats showed a preserved right ventricular morphology. Isolated pulmonary perfusion studies showed that ACEI significantly upregulated NO production, as measured by nitrite levels. Addition of N-methyl-D-glucamine dithiocarbamate-Fe solution, an NO-trapping agent, reversed the basal vasodilatory effect of ACEI in the pulmonary vasculature. Immunoblot analysis showed decreased p21 and eNOS expression in the lung in MCT(+)/ACEI(-) rats, whereas their expression was preserved with enalapril treatment.

CONCLUSIONS

ACEI suppresses the development of MCT-induced PAH in rats. The mechanism of action might involve the preservation of p21 and eNOS expression. Both p21 and endothelium-derived NO appear to have protective roles in the development of PAH.

Activation of c-Jun amino-terminal kinase is required for retinoic acid-induced neural differentiation of P19 embryonal carcinoma cells

P19 embryonal carcinoma cells are known to differentiate into neurons and glia when treated with relatively high concentrations (>100 nM) of retinoic acid (RA). Concomitant with this RA-induced neural differentiation, we observed an activation of the c-Jun amino-terminal kinase (JNK). JNK was required for the RA-induced neural differentiation, because dominant-negative JNK blocked the differentiation. Studies using protein phosphatase inhibitors and protein kinase inhibitors suggested that both okadaic acid-sensitive protein phosphatase(s) and protein kinase C participate in the RA-induced activation of JNK.

Oxidative damage to mitochondria is a preliminary step to caspase-3 activation in fluoride-induced apoptosis in HL-60 cells

It has been suggested that oxidative stress plays a major role in various forms of cell death, including necrosis and apoptosis. We have previously reported that fluoride (NaF) induces apoptosis in HL-60 cells by caspase-3 activation. The main focus of this investigation was to arrive at a possible pathway of the apoptosis induced by NaF upstream of caspase-3, because the mechanism is still unknown. The present study showed that after exposure to NaF, there was an increase in MDA and 4-HNE and a loss of mitochondrial membrane potential (deltaPsi(m)) was also observed in NaF-treated cells. There was a significant increase in cytosolic cytochrome c, which is released from the mitochondria. We have reported a downregulation of Bcl-2 protein in NaF-treated cells. The antioxidants N-acetyl cysteine (NAC), glutathione (GSH) protected the cells from loss of deltaPsi(m), and there was no cytochrome c exit or Bcl-2 downregulation, and we suggest that these antioxidants prevent apoptosis induced by NaF. These results suggested that perhaps NaF induced apoptosis by oxidative stress-induced lipid peroxidation, causing loss of deltaPsi(m), and thereby releasing cytochrome c into the cytosol and further triggering the caspase cascade leading to apoptotic cell death in HL-60 cells.

Colonization with Schizophyllum commune of localized honeycomb lung with mucus

We report a surgical case involving localized honeycomb lung with mucus, caused by colonization of a Schizophyllum commune, which displayed a tumorous shadow in the right upper mediastinum. A 74-year-old male with a history of tuberculosis in the 1970s was referred to Chiba University Hospital (Chiba, Japan) with an abnormal shadow evident in the chest roentgenogram. A transbronchial biopsy failed to yield a definite diagnosis. We resected the right upper lobe, which was found to contain a consolidative lesion filled with viscous mucus in the right upper lobe adjacent to the right upper mediastinum. Microscopic examination revealed a honeycomb lung formation with mucus in the destroyed space. Culture of the mucus yielded a whitish filamentous fungus, positively identified as S. commune. This is the first report of S. commune leading to a deposit of mucus and the formation of a consolidative lesion in the destroyed lung.

The role of myocardial gap junctions in electrical conduction and arrhythmogenesis

Electrical activation of the heart requires cell-cell transfer of current via gap junctions, arrays of densely packed protein channels that permit intercellular passage of ions and small molecules. Because current transfer occurs only at gap junctions, the spatial distribution and biophysical properties of gap junction channels are important determinants of the conduction properties of cardiac muscle. Gap junction channels are composed of members of a multigene family of proteins called connexins. As a general rule, individual cells express multiple connexins, which creates the potential for considerable functional diversity in gap junction channels. Although gap junction channels are relatively nonselective in their permeability to ions and small molecules, cardiac myocytes actively adjust their level of coupling by multiple mechanisms including changes in connexin expression, regulation of connexin trafficking and turnover, and modulation of channel properties. In advanced stages of heart disease, connexin expression and intercellular coupling are diminished, and gap junction channels become redistributed. These changes have been strongly implicated in the pathogenesis of lethal ventricular arrhythmias. Ongoing studies in genetically engineered mice are revealing insights into the role of individual gap junction channel proteins in normal cardiac function and arrhythmogenesis.

Integrated pulsed amperometric detection of glufosinate, bialaphos and glyphosate at gold electrodes in anion-exchange chromatography

A rapid and practical method for direct detection of the herbicides (glufosinate, bialaphos and glyphosate) in anion-exchange chromatography has been developed with integrated pulsed amperometric detection (IPAD). The electrochemical behavior of these herbicides showed catalytic currents based on the oxidation of amines in their structures. Waveform in IPAD was similar to that for amino acids, which exhibited adsorption/desorption catalytic features at gold electrode surface in alkaline solution. Under optimized conditions, detection limits (signal-to-noise ratio of 3) for glufosinate, bialaphos and glyphosate were 20, 65 and 50 ng ml(-1), respectively, with correlation coefficients of 0.995, 0.997 and 0.996 over concentration ranges of 0.1-45, 0.3-32 and 0.1-50 microg ml(-1), respectively. The relative standard deviations (n=5) were 1.7-3.0%. The present method was successfully applied to the determination of glyphosate in urine and serum.

RGD peptide-induced apoptosis in human leukemia HL-60 cells requires caspase-3 activation

RGD motif-containing peptides have been used in various studies of cell adhesion and growth. We report that RGD triggered apoptosis at a concentration of 1 mmol/L, whereas RAD-containing peptides failed to induce apoptosis in HL-60 cells. RGD-treated cells revealed internucleosomal DNA fragmentation. Western blot reveals caspase-3 activation in RGD peptide-treated cells. A caspase-3 inhibitor z-VAD-FMK completely blocked the apoptosis, but a caspase-1 inhibitor (Ac-YVAD-CMK) and caspase-2 inhibitor (z-VDVAD-FMK) did not block the apoptosis, suggesting that caspase-3 might have a critical role in the execution process of apoptosis induced by RGD. RGD peptides have been used extensively to inhibit tumor metastasis. Our results should help in further understanding the RGD peptide-induced apoptosis, which is important since RGD peptides have a potential role in therapies of the future.

Prognostic significance of lymph node involvement in middle and distal bile duct cancer

BACKGROUND

Although lymph node involvement is considered an important prognostic factor, a detailed analysis has not been conducted in middle (Bm) and distal (Bi) bile duct cancer.

METHODS

The histopathology of resections taken from 59 patients with Bm and Bi disease (Bm, 33 patients; Bi, 26 patients) was examined. The prevalence of lymph node involvement and its relationship to recurrence and prognosis were investigated. Survival rates were investigated according to the number of metastatic lymph nodes found, the TNM nodal stages, and the nodal stage classifications of The General Rules of the Japanese Society of Biliary Surgery.

RESULTS

The frequency of nodal involvement in Bm and Bi was 45.5% and 30.8%, respectively. A significant correlation existed between a patient's prognosis and his TNM nodal stage, Japanese Society of Biliary Surgery nodal stage, and the number of metastatic lymph nodes found (P <.0001, respectively). Among 8 sites of postoperative recurrence, metastasis occurred most frequently in the liver (16/23). Patients with nodal involvement had a significantly higher rate of liver metastasis (10/23) than those without it (6/36) (P =.024).

CONCLUSIONS

The number of metastatic lymph nodes found in patients with Bm or Bi cancer, and the nodal stage of their nodes, are significant prognostic indicators. Patients with nodal involvement are at high risk for liver metastasis in Bm and Bi disease.

Tsutsugamushi disease in Kanagawa Prefecture, Japan: clinical report of two cases and survey of other incidences in 1998

Tsutsugamushi disease is characterized by the early appearance of a black crust at the bitten area and the subsequent development of macular or macropapular rush on the whole body with high fever. While treatment with tetracycline derivatives and chloramphenicols is effective, delayed diagnosis or inappropriate treatment will lead to fatality. In this report, we describe two typical cases of tsutsugamushi disease and discuss other incidences in Kanagawa Prefecture, Japan, in 1998. One of the present two patients was diagnosed to be a case of the new type by Kawasaki strain of Rickettsia tsutsugamushi, while responsible strain was not identified for the other case. Since the disease is spreading widely even to suburban areas, we emphasize the need to consider the possible diagnosis of tsutsugamushi disease in patients with generalized eruption and high fever.

Preliminary report: effect of adrenal androgen and estrogen on bone maturation and bone mineral density

To clarify the independent physiological roles of adrenal androgen and estrogen on bone growth, we compared the lumbar spine bone mineral density (BMD) in prepubertal girls with virilizing congenital adrenal hyperplasia (CAH) (n = 17) and girls with central precocious puberty (CPP) (n = 18). When BMD was analyzed according to chronologic age, no significant differences were found between CPP and CAH patients. However, when adjusted to bone age, BMD was statistically higher in CAH than in CPP subjects. This finding suggests that adrenal androgen, as well as estrogen, plays an important role in increasing BMD. Adrenal androgen may act on bone not only as androgen, but as estrogen after having been metabolized into an aromatized bone-active compound in peripheral tissues, such as bone and fat. Therefore, adrenal androgen may have a more important role in increasing BMD than previously realized.

Signal transduction and transcriptional regulation of angiogenesis

When quiescent endothelial cells (ECs) are exposed to angiogenic factor such as VEGF; ECs express proteases to degrade extracellular matrices, migrate, proliferate and form new vessels. However, the molecular mechanism of these events is not fully characterized yet. We are studying the signal transduction and transcriptional regulation of angiogenesis. We investigated the properties of two VEGF receptors, Flt-1 and KDR, by using two newly developed blocking monoclonal antibodies (mAbs), i.e., anti-human Flt-1 mAb and anti-human KDR mAb. VEGF elicited induction of transcription factor Ets-1 in human umbilical vein endothelial cells (HUVECs). This induction was mediated by the KDR/Flt-1 heterodimer and the KDR homodimer. The role of transcription factor Ets-1 in angiogenesis was further clarified. We established both high and low Ets-1 expressing EC lines, and compared angiogenic properties of these cell lines with a parental murine EC line, MSS31. The growth rate was almost identical among three cell lines. It appeared that gene expressions of matrix metalloproteinases (MMP-1, MMP-3, and MMP-9) as well as integrin beta 3 were correlated with the level of Ets-1 expression. As a result, the invasiveness was enhanced in high Ets-1 expressing cells and reduced in low Ets-1 expressing cells compared with parental cells, and high Ets-1 expressing cells made more tube-like structures in type 1 collagen gel. These results indicate that Ets-1 is a principle transcription factor converting ECs to the angiogeneic phenotype.

Effect of sepimostat mesilate on experimental venous thrombosis in rats

Sepimostat mesilate (FUT-187: 6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl) amino] benzoate dimethane sulfonate) is a newly synthesized serine protease inhibitor. In the present study, the oral administration of FUT-187 inhibited stasis-induced venous thrombosis in rats. We supposed that such effect of this compound was caused by its inhibitory effect on coagulation. However, the dose of FUT-187 that was effective at inhibiting thrombosis (10 and 30 mg/kg, po) had no effect on the plasma recalcification time (PRCT), activated partial thromboplastin time (APTT) and prothrombin time (PT) in rats. Therefore, we investigated the fibrinolytic activity of FUT-187 in rat plasma. The results revealed that rat plasma after FUT-187 administration exhibited increased amidolytic activity for a plasmin-, tissue-type plasminogen activator (t-PA)-, urokinase-type plasminogen activator (u-PA)-, factor Xa-, factor XIa- and factor XIIa-sensitive synthetic peptide substrate. On the other hand, the inhibitory effect of FUT-187 in the thrombosis model was not affected by additional treatment with epsilon-amino-n-caproic acid (EACA), a plasmin-mediated fibrinolysis inhibitor. These results suggest that even if FUT-187 enhanced fibrinolysis, it would be independent of a plasmin-mediated fibrinolytic pathway. To characterize the fibrinolytic activity, which might reduce the thrombus weight in the thrombosis model administered FUT-187, we carried out fibrinogen zymography, and clarified that FUT-187 enhanced the formation of a 20-kDa fibrinolytic fragment. Interestingly, this fragment was not affected by t-PA. Consequently, we consider that the inhibitory effect of FUT-187 on venous thrombosis model is caused by fibrinolysis, which is attributable to the 20-kDa fragment, rather than by inhibition of thrombus formation.

Infrequent microsatellite instability in biliary tract cancer

BACKGROUND AND OBJECTIVES

Microsatellite instability (MSI) has been reported in several tumors. However, few reports are available concerning MSI in biliary tract cancers. We investigated MSI and allelic loss at the hMLH1 and hMSH2 gene loci in biliary tract cancers.

METHODS

We analyzed microsatellite alterations using 7 microsatellite markers in 38 cases of extrahepatic bile duct (EHBD) cancer and 16 cases of ampullary cancer using polymerase chain reaction and an automated fluorescent DNA sequencer.

RESULTS

A MSI prevalence of 13.2% (5/38) was observed for EHBD cancer and a prevalence of 12.5% (2/16) was observed for ampullary cancer. Loss of heterozygosity at the hMLH1 and hMSH2 gene loci were observed in 4% (1/25 informative cases) and 6.1% (2/33) of EHBD cancer cases, respectively; and in 11.1% (1/9) and 8.3% (1/12) of ampullary cancer cases, respectively. The cumulative survival rate of patients with MSI was significantly better than that of patients without MSI in EHBD cancer. However, MSI was not an independent prognostic factor.

CONCLUSIONS

Our results suggest that genetic defects in the DNA mismatch repair system and MSI do not play an important role in the majority of biliary tract cancers.

Cyclohexane as an alternative vapor of carbon tetrachloride for the assessment of gas removing capacities of gas masks

An alternative vapor was explored to replace carbon tetrachloride (CCl4) for testing breakthrough times of cartridges and canisters of gas masks in the National Approval Test of Respirators. Cyclohexane was single out as a candidate for the alternative vapor out of six vapors: trichloroethylene, n-pentane, n-hexane, n-heptane, toluene and cyclohexane from the viewpoints of similarity of vapor pressure and water-solubility to CCl4, lower toxicity than CCl4, and technical feasibility in generating an airflow of 30 L/min containing the vapor ranging from 300 to 5000 ppm. Breakthrough times of cartridges and canisters were examined by generating cyclohexane vapor in a test airflow of 30 L/min in comparison with CCl4 vapor under various test conditions with different vapor concentrations and relative humidities (RH). As the results, the breakthrough times of the cartridges and canisters for cyclohexane were found to almost coincide with those for CCl4 under all examined range of concentrations and RH. By an increase of humidity from 50% RH to 80% RH, the cartridges showed significant shortening of breakthrough times for both of CCl4 and cyclohexane, but the susceptibility of the breakthrough time of cyclohexane to humidity was also similar to that of CCl4. It was, therefore, concluded that cyclohexane can be recommended as the alternative vapor of CCl4 for testing the breakthrough times of gas mask cartridges and canisters in the National Approval Test.

[Complications in home treatment of patients with severe disturbances of consciousness]

We have been providing home treatment for patients with severe disturbance of consciousness requiring various medical treatments for about 10 years. In the 65 cases we have encountered, we studied complications during the course of the home treatment. The proportions of infections, decubiti and convulsions were found to be very high. With infections in particular, conditions worsened rapidly in many cases, so we made it a principle to have the patients hospitalized early. We also investigated changes in serum albumin levels, peripheral blood lymphocyte count and prognostic nutritional index (PNI). Patients who develop infections repeatedly and succumb to early death often show low values for PNI and lymphocyte count. The low values are considered useful as one indicator of the general conditions of patients under home treatment. For the management of patients with severe disturbances of consciousness, it is important to keep a close liaison with other departments or hospitals and strengthen home nursing sections.

A novel approach with magnetic resonance imaging used for the detection of lung allograft rejection

OBJECTIVE

Although various techniques have been explored for the detection and quantification of allograft transplant rejection, a practical and reliable method that is noninvasive is still elusive.

METHODS

For our magnetic resonance imaging experiments, we have developed a new rat model of heterotopic lung transplantation to the inguinal region. Allogeneic transplants (DA to Brown Norway) were performed with and without cyclosporine A (INN: ciclosporin) treatment, with syngeneic transplants (Brown Norway to Brown Norway) serving as controls (n = 6 per group). Magnetic resonance images were obtained with a gradient echo method before and after injection of ultra-small superparamagnetic iron oxide particles.

RESULTS

At day 5, allogeneic transplants without cyclosporine A treatment showed a grade 4 rejection histologically. A significantly lower magnetic resonance signal was seen 24 hours after injection of ultra-small superparamagnetic iron oxide particles compared with the preinjection image (346 +/- 7.6 vs 839 +/- 43.4 arbitrary units; P <. 05). Syngeneic transplants showed no evidence of rejection histologically and no differences in magnetic resonance imaging signals between the images before and after injection of ultra-small superparamagnetic iron oxide particles (863 +/- 18.8 vs 880 +/- 22.5). Allotransplants treated with cyclosporine A showed a grade 2 rejection histologically. The change in magnetic resonance signals in that group was small but showed a significant decrease in signal intensity after injection (646 +/- 10.5 vs 889 +/- 23.5, P <.05). Immunohistochemistry and iron staining of the allografts indicated that ultra-small superparamagnetic iron oxide particles were taken up by the infiltrating macrophages that accumulated at the rejection site.

CONCLUSIONS

We have demonstrated a novel approach for the detection of acute lung allograft rejection using magnetic resonance imaging coupled with injection of ultra-small superparamagnetic iron oxide particles. Despite its limitations, our method might be a first step toward a potential clinical application.

Cellular responses and repair of single-strand breaks introduced by UV damage endonuclease in mammalian cells

Although single-strand breaks (SSBs) occur frequently, the cellular responses and repair of SSB are not well understood. To address this, we established mammalian cell lines expressing Neurospora crassa UV damage endonuclease (UVDE), which introduces a SSB with a 3'-OH immediately 5' to UV-induced cyclobutane pyrimidine dimers or 6-4 photoproducts and initiates an alternative excision repair process. Xeroderma pigmentosum group A cells expressing UVDE show UV resistance of almost the wild-type level. In these cells SSBs are produced upon UV irradiation and then efficiently repaired. The repair patch size is about seven nucleotides, and repair synthesis is decreased to 30% by aphidicolin, suggesting the involvement of a DNA polymerase delta/epsilon-dependent long-patch repair. Immediately after UV irradiation, cellular proteins are poly(ADP-ribosyl)ated. The UV resistance of the cells is decreased in the presence of 3-aminobenzamide, an inhibitor of poly(ADP-ribose) polymerase. Expression of UVDE in XRCC1-defective EM9, a Chinese hamster ovary cell line, greatly sensitizes the host cells to UV, and addition of 3-aminobenzamide results in almost no further sensitization of the cells to UV. Thus, we show that XRCC1 and PARP are involved in the same pathway for the repair of SSBs.

Visual and tear function improvement after superficial phototherapeutic keratectomy (PTK) for mid-stromal corneal scarring

PURPOSE

To study the changes in visual and tear film function following superficial excimer laser phototherapeutic keratectomy in patients with mid-stromal corneal scars.

METHODS

Fourteen eyes of 14 patients with mid-stromal corneal scars seen at the Department of Ophthalmology at Kobe Kaisei Hospital underwent superficial phototherapeutic keratectomy (PTK). The subjects underwent routine ophthalmic examinations, corneal sensitivity measurements, tear film break-up time (BUT), Schrimer test and tear film lipid layer interferometry. Thirty eyes of 15 normal control subjects were also studied. The patients and the control subjects were compared for pre-PTK tear function parameters and tear film lipid layer interferometry grade. The alterations in these parameters within 6 months following PTK were also determined.

RESULTS

Visual improvement was achieved in 12 eyes (86%). A hyperopic shift was observed in all eyes. The average pre-PTK corneal sensitivity and tear film BUT were lower in patients compared with control subjects before PTK. Tear film lipid layer interferometry grades were also higher in the patients than the controls before PTK. All these parameters improved gradually and significantly after PTK. Schirmer test results did not show any significant alterations after PTK.

CONCLUSION

We conclude that PTK is an effective means of treating corneal scars and attaining visual improvement, even in cases with deeper corneal involvement, and may obviate the need for corneal transplantation. Simultaneous improvements in corneal sensitivity and tear film stability suggest favourable effects of PTK on the ocular surface.

Transcription of krox-20/egr-2 is upregulated after exposure to fibrous particles and adhesion in rat alveolar macrophages

Alveolar macrophages meet various types of particulate substances deposited deep in the lung. We report differences in biologic responses of alveolar macrophages between phagocytosis of fine spherical and fibrous particles. Although titanium dioxide (TiO(2)) is thought to be biologically inert, the cytotoxicity of fibrous TiO(2) (F-TiO(2)) was much higher than spherical TiO(2) (S-TiO(2)). Differential display and the subsequent Northern blot analysis indicated that transcription of krox-20/egr-2 gene was slightly and greatly upregulated in S- and F-TiO(2)-exposed alveolar macrophages, respectively. The messenger RNA (mRNA) level of krox-20/egr-2 increased up to 8 h in F-TiO(2)-exposed alveolar macrophages, whereas krox-20/egr-2 mRNA level was transiently increased in response to adhesion to the culture dish. Stimulation with lipopolysaccharide also increased krox-20/egr-2 mRNA level transiently, although the mRNA level rebounded after 8 h. The analysis with 5' rapid amplification of complementary DNA ends suggested that there is a heterogeneity in the upstream region of this gene (krox-20/egr-2 and krox-20H1; accession numbers AB032420 and AB032419, respectively). The polymerase chain reaction analysis with specific primers for krox-20/egr-2 and krox-20H1 indicated that both genes were almost equally upregulated after either adhesion to the plastic dish or phagocytosis of F-TiO(2). These results suggest that both krox-20/egr-2 and krox-20H1 are implicated in adhesion and phagocytosis, and that the expression of krox-20 may reflect interaction with foreign substances and adhesion in alveolar macrophages.

Impact of sequential grafting of the internal thoracic or right gastroepiploic arteries on multiple coronary revascularization

OBJECTIVE

The aim of the study is to clarify the efficacy of the sequential anastomotic technique of the arterial conduits for multiple coronary revascularization.

BACKGROUND

The internal thoracic artery (ITA) is now widely accepted as a durable conduit for myocardial revascularization. The right gastroepiploic artery (GEA) has been developed as a third in situ arterial graft with an outcome similar to that of the ITA.

MATERIAL AND METHOD

One hundred and forty five consecutive patients (116 male, 29 female, mean age 60.4yr) who received sequential grafting of either the ITA or GEA or both were retrospectively analysed.

RESULTS

Sequential anastomoses were performed in 121 in situ left ITAs, 36 in situ GEAs and 12 composite right ITAs. No in situ right ITA was anastomosed sequentially. Two to six vessels (mean 3.8) were revascularized for each patient. Of the total 543 bypassed vessels, 432 (79.6%) were reconstructed with the arterial grafts. In 85 patients with quadruple bypass or more, the arterial grafts were able to reconstruct 266 out of 360 (74.0%) target vessels. Seventy one patients (49.0%) were revascularized without venous grafts. The arterial grafts could revascularize 293 out of 310 vessels (94.5%) in the LAD approximately Diagonal region, 83 out of 113 (73.4%) in the distal RCA or Cx region. There were no cardiac events responsible for the arterial grafts in the follow up period.

CONCLUSION

In light of our experience, multiple revascularization with in situ arterial sequential grafts is feasible. Aggressive application of this technique provides patients requiring multiple coronary revascularization with favorable long-term results.

Fluoride induces apoptosis by caspase-3 activation in human leukemia HL-60 cells

Even though fluoride toxicity is increasingly being considered to be important, very little information is available on the mechanism of action of fluoride. In the present study, the toxicity of fluoride on human leukemia (HL-60) cells was investigated and the involvement of caspase-3 was also studied. Fluoride induced apoptosis in HL-60 cells in a dose- and time-dependent manner. Annexin staining and DNA ladder formation on agarose gel electrophoresis further revealed that HL-60 cells underwent apoptosis on exposure to 2-5 mM fluoride. Western blotting using polyclonal anti-caspase-3 antibody and mouse anti-human poly(ADP-ribose) polymerase (PARP) monoclonal antibody was performed to investigate caspase-3 and PARP activity. Fluoride led to the activation of caspase-3 which was evident by the loss of the 32 kDa precursor and appearance of the 17 kDa subunit. Furthermore, intact 116 kDa PARP was cleaved by fluoride treatment as shown by the appearance of a cleaved 89 kDa fragment. The results clearly suggest that fluoride causes cell death in HL-60 cells by causing the activation of caspase-3 which in turn cleaves PARP leading to DNA damage and ultimately cell death.

Attenuation of myocardial ischemia/reperfusion injury by superinduction of inducible nitric oxide synthase

BACKGROUND

Nitric oxide (NO) has been implicated as a mediator in myocardial ischemia/reperfusion (I/R) injury, but its functional properties have been conflicting. We investigated whether NO has a protective role against I/R injury.

METHODS AND RESULTS

Using endothelial NO synthase knockout (eNOS KO) mice, inducible NOS KO mice, the NO donor S-nitroso-N-acetylpenicillamine (SNAP), and the NOS inhibitor N-iminoethyl-L-ornithine (L-NIO), we performed studies of isolated perfused hearts subjected to 30 minutes of global ischemia followed by reperfusion. After 60 minutes of reperfusion, nitrite levels in the coronary effluent in the SNAP and eNOS KO groups were significantly elevated compared with other groups. Immunoblot and immunohistochemistry showed that iNOS was markedly induced in the eNOS KO hearts. Under spontaneous beating conditions during reperfusion, increased NO activity was correlated with a prevention of the hyperdynamic contractile response and enhanced myocardial protection, as evidenced by a reduction in myocardial injury and infarct size. During prolonged reperfusion, SNAP-treated hearts were able to preserve contractile functions for 180 minutes, whereas L-NIO-treated hearts showed a sustained deterioration in contractility.

CONCLUSIONS

NO protects against I/R injury by preventing the hyperdynamic response of isolated perfused hearts during early reperfusion. In the eNOS KO hearts, a paradoxical increase in NO production was seen, accompanied by a superinduction of iNOS, possibly due to an adaptive mechanism.