A phase I study of amrubicin (AMR) and irinotecan (CPT-11) in relapsed small cell lung cancer

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Background: AMR and CPT-11 have shown excellent activity in extensive small cell lung cancer (SCLC). The aim of this study was to determine the maximum tolerated dose (MTD) of amrubicin in combination with a fixed dose of CPT-11. Methods: Eligibility criteria were patients having pathologically proven SCLC, had relapsed after one or two previous chemotherapies, ECOG performance status (PS) of 0–2 and adequate organ function. Irinotecan was delivered as 50 mg/m2 on days 1 and 8, every 21 days. AMR was delivered on day 1. Doses of AMR were level 1: 80mg/ m2, level 2: 90 mg/m2 and level 3: 100 mg/ m2. Dose elevation was determined using continuous reassessment method (CRM). Tolerability was assessed after the 1st cycle. Another two cycles were conducted when disease progression or unacceptable toxicities were not observed. Results: Between June 2004 and October 2006, 18 patients were enrolled with the following characteristics: male/female, 15/3; median age, 66.3 years (range 57–61); PS 0/1/2: 4/14/0. Median number of previous treatment cycles was 5. A total of 40 courses were conducted. Grade 3/4 hematological toxicities of 1st cycle were: leukocytopenia: 67% (G3/4: 8/4); neutropenia: 89% (G3/4: 6/10), thrombocytopenia: 11% (G3/4: 1/1). Grade 3 febrile neutropenia occurred in 1 patient. Other grade 3 or greater non-hematological toxicities were observed in 4 of 40 courses (grade 3 infection in 3 courses and diarrhea in 1). In the first course, DLT was observed in 2 of 6 patients at dose level 2 (prolonged grade 4 neutropenia, febrile neutropenia), in 1 of 6 at dose level 3 (prolonged grade 4 neutropenia), MTD of amrubicin were determined by CRM to be 100 mg/m2 (level 3). Objective response was obtained in 4 patients (28%). Conclusions: This combination was well tolerated and showed activities in SCLC, though hematological toxicities were rather severe. Phase II trials are being planned in chemo naïve SCLC.

No significant financial relationships to disclose.

Clinical outcomes of a multi-institutional retrospective study for 419 patients with locally advanced non-small cell lung cancer (NSCLC)

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Background: Chemo-Radiotherapy (CRT) is considered the standard of care in locally advanced NSCLC. However, regimen of chemotherapy (CT), schedule of radiotherapy (RT), and application for surgical interventions (OP) are still controversial. We performed a study to establish clinical outcomes of NSCLC patients treated with CRT in Japan. Methods: A total of 373 consecutive patients (CRT: 307, OP after CRT (OP/CRT): 66) with stage III NSCLC, PS 0–2, no indications of OP at the initial evaluation, treated with CRT between January 1997 and December 2002 were analyzed. We also investigated 46 patients treated with RT alone as control. Results: We investigated a total of 419 patients (354 men and 65 women; average age: 64.5 ± 9.5 years) from nine institutes. Distributions of pathological subtypes were: squamous cell carcinoma: 225; adenocarcinoma: 154; large cell carcinoma: 14; non-small cell carcinoma: 26. In 189 stage IIIA patients, median survival time (MST) was 21.2 M, and MST of CRT, OP/CRT and RT were 19.1 M, 61.7 M, and 18.0 M, respectively. Multivariate analysis with Cox proportional hazards model indicates age, PS, existence of double cancer, existence of diabetes mellitus, stage IIIB, white blood cell counts increase, hemoglobin decrease as significant prognostic factors in CRT or OP/CRT patients. Multivariate analysis in stage IIIA patients indicated BMI decrease, double cancer, body weight loss, white blood cell increase, hemoglobin decrease as prognostic factors. There was a statistically significant difference between overall survival of CRT and OP/CRT in stage IIIA patients (p = 0.038 after adjustment for the effect of prognostic factors). However, there were no differences between CRT and RT, and among any schedules of CRT therapy. Conclusions: This clinical study suggests that OP after CRT could results in good survival compared with CRT alone, and BMI, double cancer, body weight loss, white blood cell, and hemoglobin could be prognostic factors in locally advanced NSCLC.

No significant financial relationships to disclose.

High sensitivity C-reactive protein in asthma

Asthma is characterised by chronic inflammation of the airways, but the relevance of high-sensitivity assays for C-reactive protein (hs-CRP), which are known to be a sensitive marker of low-grade systemic inflammation, has not been fully studied in asthma. The objective was to examine serum hs-CRP levels in patients with asthma and their relationship to clinical characteristics and degree of airway inflammation. Serum hs-CRP levels were cross-sectionally examined in steroid-naive (n = 22) and steroid-inhaling (n = 23) adult patients with asthma and healthy controls (n = 14). All were nonsmokers. Serum hs-CRP levels were significantly increased in steroid-naive patients (mean+/-sd 1.33+/-1.48 mg.L(-1)) compared with controls (0.21+/-0.30 mg.L(-1)), but not in patients on inhaled corticosteroid. Among steroid-naive patients, serum hs-CRP levels significantly negatively correlated with indices of pulmonary function (forced expiratory volume in one second/forced vital capacity and forced mid-expiratory flow) and positively with sputum eosinophil count. Among patients on inhaled corticosteroid, hs-CRP levels did not correlate with any indices. In conclusion, an increase in serum C-reactive protein levels measured by high-sensitivity assays may be associated with airflow obstruction and airway inflammation, and may serve as a surrogate marker of airway inflammation in asthma.

Relationship of airway wall thickening to an imbalance between matrix metalloproteinase-9 and its inhibitor in asthma

BACKGROUND

The balance between matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) may be critical in extracellular matrix remodelling, a characteristic of asthmatic airways. An excess of TIMP-1 over MMP-9 has been associated with chronic airflow obstruction but the mechanisms underlying this association remain unknown. Recent computed tomographic (CT) studies indicate that airway wall thickening is associated with chronic airflow obstruction.

METHODS

Sputum levels of MMP-9, TIMP-1, and their molar ratio were examined in 26 patients with stable asthma and their relationship with pulmonary function and airway wall thickness, assessed by a validated CT technique which measured wall area corrected by body surface area (WA/BSA), the ratio of WA to outer wall area (WA%), and the absolute wall thickness corrected by radicalBSA of a segmental bronchus (T/ radicalBSA), was examined.

RESULTS

Sputum MMP-9 levels were inversely correlated with WA% and TIMP-1 levels were positively correlated with WA/BSA and T/ radicalBSA. The MMP-9/TIMP-1 molar ratio was inversely correlated with WA% and T/ radicalBSA and positively correlated with post-bronchodilator values of mid-forced expiratory flow and maximum expiratory flow at the quartile of lung volume.

CONCLUSION

Excess TIMP-1 may have a pathogenetic role in airway wall thickening in asthmatic patients which may result in chronic airflow obstruction.

Gamma radiation inhibits fibroblast-mediated collagen gel retraction

Radiation exposure is known to impair healing in irradiated areas. Fibroblasts play a major role in the production and modification of extracellular matrix in wound repair. Since one important aspect of wound repair is the contraction of the wound, this study investigated the effects of radiation on the ability of fibroblasts to mediate collagen gel contraction in an in vitro model of wound retraction. After irradiation, the cells were detached and suspended in a solution of rat tail tendon collagen. Radiation exposure decreased retraction, and this effect was dose dependent. In order to define the mechanism of reduced gel retraction, we investigated alpha2beta1 cell surface integrin and fibronectin, which are thought to mediate contraction, and prostaglandin E2 (PGE2), which is known to inhibit this process. PGE2 release increased dose responsively following radiation. The cyclooxygenase inhibitor indomethacin could partially restore the contractile activity of irradiated fibroblasts. Fibronectin production in gel culture showed a significant decrease. In contrast, there was no decrease in alpha2beta1 integrin expression in radiated cells. In conclusion, radiation decreases fibroblast-mediated gel contraction. Increased PGE2 production and decreased fibronectin production by irradiated fibroblasts may contribute to this effect and may be in part responsible for poor healing of radiated tissue.

Fibrogenic and inflammatory cytokines modulate mRNA expressions of matrix metalloproteinase-3 and tissue inhibitor of metalloproteinase-3 in type II pneumocytes

BACKGROUND

Imbalance between proteinases and their inhibitors released from alveolar type II pneumocytes may cause development of inflammatory lung diseases.

OBJECTIVES AND METHODS

We examined mRNA expressions of matrix metalloproteinase-3 (MMP-3) and tissue inhibitor of metalloproteinase-3 (TIMP-3) in a cell line (A549) and in primary culture of normal adult human type II pneumocytes using reverse transcription-competitive polymerase chain reaction.

RESULTS

Interleukin-1beta (IL-1beta) and transforming growth factor-beta1 (TGF-beta1) increased MMP-3 and TIMP-3 expressions in A549 cells in a time- and concentration-dependent manner. IL-1beta mainly augmented MMP-3 expression, while TGF-beta1 mainly augmented TIMP-3 expression. Dexamethasone attenuated both IL-1beta- and TGF-beta1-stimulated expressions of MMP-3 and TIMP-3. Interleukin-10 had no significant effect. Hepatocyte growth factor alone had no effect on constitutive MMP-3 expression or TIMP-3 expression, but it augmented TGF-beta1-stimulated MMP-3 expression. The constitutive expressions were higher in normal type II pneumocytes than in A549 cells, but the regulations were similar.

CONCLUSIONS

These data indicated that the matrix degradation is enhanced by IL-1beta and suppressed by TGF-beta1 via regulations in the balance between MMP-3 and TIMP-3. Further, these regulations were shown to be modulated by glucocorticoids and growth factors.

Significance of increase in lipocortin-1 gene transcripts in the blood monocytes of patients with pulmonary sarcoidosis

BACKGROUND AND AIM OF THE WORK

Lipocortin-1 (also known as annexin-1) is upregulated by corticosteroids and plays a prominent part in many of their anti-inflammatory actions. In our previou investigation, lipocortin-1 gene expression in blood monocytes was higher in sarcoidosis patients tha in healthy subjects or IPF patients. In this study, we examined the amounts of lipocortin-1 gene tran scripts [at baseline and after stimulation by synthetic adrenocorticotrophic hormone (ACTH)] in the blood monocytes of sarcoidosis patients, and then we analyzed the relationships between these amount and several clinical indexes.

METHODS

Serum and blood monocyte samples were prepared from 21 sar coidosis patients before and after ACTH stimulation. The amounts of lipocortin-1 and beta-actin gene tran scripts obtained from monocytes were quantified by RT-PCR. The patients were prospectively followe for at least 2.5 years.

RESULTS

1. Serum cortisol was increased in all patients after synthetic ACTH in jection. 2. Lipocortin-1 gene transcripts tended to increase in parallel with increases in serum cortisol but the relationship was not significant. 3. The amounts of lipocortin-1 gene transcripts induced by syn thetic ACTH were related to two indexes of disease activity/extension: the presence of parenchymal lesions (p = 0.018), and the presence of extrathoracic lesions (p = 0.043). 4. After 3 years of follow-up the patients with higher basal amounts of lipocortin-1 gene transcripts in monocytes showed improve ment of sACE activity and FEV1/FVC%.

CONCLUSION

The amounts of lipocortin-1 gene transcripts induced by synthetic ACTH were related to the presence of parenchymal lesions, while their basa amounts correlated with either improvement of sACE activity or stabilization of FEV1/FVC%.

Cytotoxic effects of cigarette smoke extract on an alveolar type II cell-derived cell line

Injury of the alveolar epithelium by cigarette smoke is presumed to be an important process in the pathogenesis of smoking-related pulmonary diseases. We investigated the cytotoxic effects of cigarette smoke extract (CSE) on an alveolar type II cell-derived cell line (A549). CSE caused apoptosis at concentrations of 5% or less and necrosis at 10% or more. When CSE was exposed to air before application to A549 cells, the cytotoxic effects were attenuated. CSE caused cell death without direct contact with the cells. Acrolein and hydrogen peroxide, two major volatile factors in cigarette smoke, caused cell death in a similar manner. Aldehyde dehydrogenase, a scavenger of aldehydes, and N-acetylcysteine, a scavenger of oxidants and aldehydes, completely inhibited CSE-induced apoptosis. CSE and acrolein increased intracellular oxidant activity. In conclusion, apoptosis of alveolar epithelial cells may be one of the mechanisms of lung injury induced by cigarette smoking. This cytotoxic effect might be due to an interaction between aldehydes and oxidants present in CSE or formed in CSE-exposed cells.

[Relationship between changes in skin lipids by ultraviolet exposure and the cell toxicity]

The oxidative decomposition of skin lipids by UV exposure and its cell toxicity were studied in vivo and in vitro, using guinea pigs, to investigate the role of oxidative damage in cell membranes and mitochondria in nuclear genome DNA damage resulting in skin cell death by ultraviolet (UV) exposure. Two new methods were developed for this research: selective methylation by trimethylsilyldiazomethane (TMSCHN2) of free fatty acids in crude skin lipids for gas chromatography-mass spectrometry (GC-MS) analysis, and the improvement of the thiobarbituric acid (TBA) reaction for lipid peroxide analysis, which was obtained by adding 0.01% BHT and 1 mM EDTA, an antioxidant additive, into the reaction system described by Ohkawa. The following findings were noted: 1. Using an optical microscope, the infiltration of inflammatory cells such as neutrophils, lymphocytes and monocytes was noted after skin tissue was exposed to UV. 2. The increase of lipid peroxide in exposed areas was small. In the epidermis the increase was about 2 times higher than the non-exposed areas. 3. The fragments of lipid were generated in accordance with the increase of free fatty acids (C16:0, C18:1,:2, C18:0) in the surface of the exposed skin by GC-MS precise assay, and the level of 7-dehydrocholesterol was decreased. 4. The skin homogenate received peroxidation by ultraviolet more easily than living skin, and its peroxidation was inhibited with fat-soluble antioxidative agents such as flavonoids, BHT, BHA, and vitamin E and the metal chelating agent such as Fenton reaction inhibitor as expected; however, it was promoted by water soluble antioxidative agents such as glutathione and vitamin C, which are useful to the human body. 5. Steroids and nonsteroidal anti-inflammatory drugs (NSAIDs) such as indomethacin and aspirin, had no inhibitory effect on lipid peroxidation by ultraviolet as properties of chemicals.

Bradykinin augments fibroblast-mediated contraction of released collagen gels

Bradykinin is a multifunctional mediator of inflammation believed to have a role in asthma, a disorder associated with remodeling of extracellular connective tissue. Using contraction of collagen gels as an in vitro model of wound contraction, we assessed the effects of bradykinin tissue on remodeling. Human fetal lung fibroblasts were embedded in type I collagen gels and cultured for 5 days. After release, the floating gels were cultured in the presence of bradykinin. Bradykinin significantly stimulated contraction in a concentration- and time-dependent manner. Coincubation with phosphoramidon augmented the effect of 10(-9) and 10(-8) M bradykinin. A B2 receptor antagonist attenuated the effect of bradykinin, whereas a B1 receptor antagonist had no effect, suggesting that the effect is mediated by the B2 receptor. An inhibitor of intracellular Ca2+ mobilization abolished the response; addition of EGTA to the culture medium attenuated the contraction of control gels but did not modulate the response to bradykinin. In contrast, the phospholipase C inhibitor U-73122 and the protein kinase C inhibitors staurosporine and GF-109203X attenuated the responses. These data suggest that by augmenting the contractility of fibroblasts, bradykinin may have an important role in remodeling of extracellular matrix that may result in tissue dysfunction in chronic inflammatory diseases, such as asthma.

Identification and characterization of the genes for N-acetylglucosamine kinase and N-acetylglucosamine-phosphate deacetylase in the pathogenic fungus Candida albicans

Like bacteria and many fungi, the pathogenic fungus Candida albicans can utilize GlcNAc as a carbon source for growth. A cluster of six genes was identified in the C. albicans genome. One of the genes in the cluster was CaNAG1, which is responsible for GlcN6P deaminase and is therefore essential for GlcNAc-dependent growth. The other five genes were designated CaNAG2, CaNAG3, CaNAG4, CaNAG5 and CaNAG6. The mRNA levels of CaNAG1, CaNAG2 and CaNAG5 were significantly induced by GlcNAc, whereas those of CaNAG3, CaNAG4 and CaNAG6 were not. Neither CaNAG2 nor CaNAG5 was essential for growth, but disruption of CaNAG2 or CaNAG5 greatly retarded the growth of cells using GlcNAc as the sole carbon source. Although no homolog of CaNAG2 or CaNAG5 was found in the Saccharomyces cerevisiae genome, CaNag2p displayed sequence similarities to Escherichia coli nagA, and CaNag5p is homologous to a wide variety of hexose kinases. When expressed as a fusion protein with glutathione S-transferase (GST), CaNag5p produced GlcNAc-P from GlcNAc in the presence of ATP, whereas GST alone did not. Furthermore, the recombinant GST-CaNag2p fusion protein converted GlcNAcP, which was produced by CaNag5p, into GlcNP. These results clearly demonstrate that CaNAG2 and CaNAG5 encode GlcNAcP deacetylase and GlcNAc kinase, respectively. CaNag5p recognized glucose and mannose as substrates, whereas the recently identified human GlcNAc kinase was specific to GlcNAc. Deletion of CaNAG2 or CaNAG5 markedly, and that of CaNAG1 moderately, attenuated the virulence of C. albicans in a mouse systemic infection model. Thus, it appears that GlcNAc metabolism of C. albicans is closely associated with its virulence.

Influence of admission functional status on functional change after stroke rehabilitation

OBJECTIVE

To determine whether the admission functional score influences the functional change after stroke rehabilitation.

DESIGN

Two hundred forty-three patients who had received the Functional Independence Measure (FIM) assessment at admission and at discharge were enrolled in the study. The patients were stratified into three groups according to their FIM total scores at admission, i.e., < or =36, 37 to 72, and > or =73.

RESULTS

The Scheffé's multiple comparison test showed that patients with FIM total scores of > or =73 at admission were significantly younger (58 +/- 11 [SD] yr) than those who had scores of 37 to 72 (64 +/- 11 yr) or < or =36 (66 +/- 12 yr). Patients with FIM total scores of 37 to 72 at admission showed significantly higher FIM gain (37 +/- 15) compared with those patients who had scores of > or =73 (20 +/- 10) or < or =36 (29 +/- 23).

CONCLUSION

The functional levels of affected patients at admission stratified by the FIM scale roughly predict the degree of functional gain after rehabilitation in survivors with a first episode of ischemic stroke. Moderately affected patients will benefit from intensive rehabilitation. These findings may be useful for rehabilitation triage.

Influence of initial status on functional gain for Japanese patients with first cerebral hemorrhage

It is important to identify in advance patients who will achieve the greatest functional gains from rehabilitation therapy, as specialist rehabilitation resources are still scarce in Japan. The purpose of this study was to determine whether functional score at admission influences the functional change (functional score at discharge minus functional score at admission) after inpatient rehabilitation for first cerebral hemorrhage. One hundred and ninety-three patients with cerebral hemorrhage were enrolled in this study. They were assessed using the Functional Independence Measure (FIM) at admission and discharge and underwent inpatient rehabilitation treatment. Patients were stratified into 3 groups according to their FIM total scores on admission as follows: (1) < or = 36 (severely affected patient group); (2) 37-72 (moderately affected patient group); and (3) >73 (mildly affected patient group). Scheffe's multiple comparison test showed that patients in group 1 were significantly older (mean +/- SD = 63 +/- 10 years) than those in groups 2 (56 +/- 10 years) or 3 (53 +/- 12 years). Patients in group 2 showed significantly greater FIM gain (37 +/- 17) compared with patients in groups 3 (23 +/- 12) or 1 (27 +/- 23). The results suggest that moderately affected patients at admission will show significantly higher functional gain compared with severely or mildly affected patients. Mildly affected patients at admission had a significantly shorter length of hospital stay for rehabilitation than the other groups. There was no significant difference in onset to admission interval between the 3 groups. The functional levels of affected patients on admission, as stratified by the FIM scale, roughly predict the degree of functional gain following rehabilitation in patients with first cerebral hemorrhage. Moderately affected patients will benefit from intensive rehabilitation. This study may be useful in determining how best to prioritize rehabilitation therapy.

Fibroblast contractility: usual interstitial pneumonia and nonspecific interstitial pneumonia

The aim of this study was to compare the function of lung fibroblasts obtained from surgically biopsied specimens of patients with idiopathic pulmonary fibrosis/usual interstitial pneumonia (UIP; n = 5), nonspecific interstitial pneumonia (NSIP; n = 5), and normal parts of surgically resected lungs (control; n = 5). The results showed that (1) fibroblasts obtained from UIP showed increased contractility compared with those obtained from NSIP or controls (UIP, 72.7 +/- 6.21%; NSIP, 32.8 +/- 5.46; controls, 28.5 +/- 3.51, p < 0.01 in UIP versus NSIP or control); (2) this increase in contractility was consistent with enhanced F-actin content in fibroblasts; (3) conditioned media from UIP fibroblast cultures enhanced control fibroblast contractility, whereas those obtained from NSIP or controls did not; (4) the 180 and 25 kD products representing the contractility in conditioned media were identified as fibronectin (ED-A domain) and TGF-beta1 by immunoblots, respectively; (5) the UIP-conditioned media contained higher amounts of fibronectin or TGF-beta 1 (fibronectin: UIP 289 +/- 47.1 ng/ml, NSIP 121 +/- 23.0, control 118 +/- 16.0; TGF-beta1: UIP 798 +/- 119 pg/ml, NSIP 246 +/- 69.1, control 247 +/- 53.6, p < 0.01 in UIP versus NSIP or control); () the contractility positively correlated with the amount of either fibronectin (r = 0.867, p < 0.001, n = 15) or TGF-beta 1 (r = 0.939, p < 0.001, n = 15), respectively. Thus, UIP fibroblasts showed greater contractility than did NSIP fibroblasts and up-regulated control fibroblasts.

Tetracycline-regulatable system to tightly control gene expression in the pathogenic fungus Candida albicans

Conventional tools for elucidating gene function are relatively scarce in Candida albicans, the most prevalent human fungal pathogen. To this end, we developed a convenient system to control gene expression in C. albicans by the tetracycline-regulatable (TR) promoters. When the sea pansy Renilla reniformis luciferase gene (RLUC1) was placed under the control of this system, doxycycline (DOX) inhibited the luciferase activity almost completely. In the absence of DOX, the RLUC1 gene was induced to express luciferase at a level 400- to 1,000-fold higher than that in the presence of DOX. The same results were obtained in hypha-forming cells. The replacement of N-myristoyltransferase or translation elongation factor 3 promoters with TR promoters conferred a DOX-dependent growth defect in culture media. Furthermore, all the mice infected with these mutants, which are still virulent, survived following DOX administration. Consistently, we observed that the number of these mutant cells recovered from the mouse kidneys was significantly reduced following DOX administration. Thus, this system is useful for investigating gene functions, since this system is able to function in both in vitro and in vivo settings.

Comparative analysis of plasma and erythrocyte 7-ketocholesterol as a marker for oxidative stress in patients with diabetes mellitus

OBJECTIVES

To reveal increased lipid peroxidation in diabetics by quantification of cholesterol oxidation products (COPs) not only in plasma, but also in erythrocytes.

DESIGN AND METHODS

We quantified 7-ketocholesterol (7-kCho) by gas chromatography-mass spectrometry as a surrogate measure for COPs. These assays were performed on both plasma and erythrocytes in 20 control subjects and 20 treated patients with relatively poorly controlled Type 2 diabetes.

RESULTS

Both plasma and erythrocyte 7-kCho levels in diabetics were significantly higher than those in control subjects. Although neither plasma nor erythrocyte 7-kCho levels were associated with markers for glucose tolerance in diabetics, a negative correlation of serum HDL-cholesterol levels with erythrocyte, but not plasma, 7-kCho levels was found.

CONCLUSION

Increased oxidative stress in diabetics affects oxidation of cholesterol. Assays of COPs not only in plasma, but also in erythrocytes, may yield complementary information in lipid peroxidation.

Significance of the interleukin-1 receptor antagonist/interleukin-1 beta ratio as a prognostic factor in patients with pulmonary sarcoidosis

BACKGROUND

Various factors such as serum angiotensin-converting enzyme (sACE) activity, bronchoalveolar lavage (BAL) fluid lymphocyte percent, CD4/CD8 ratio, and shadows on chest radiograph have been identified as indexes of disease activity in patients with sarcoidosis. However, it remains to be confirmed whether these factors can predict clinical outcomes.

OBJECTIVE

To examine whether the interleukin-1 receptor antagonist (IL-1ra)/IL-1 beta ratio can predict the clinical course, we prospectively followed the clinical courses of 30 patients with pulmonary sarcoidosis 4 years after measurement of immunoreactive amounts of IL-1ra or IL-1 beta in the culture supernatants obtained from BAL fluid macrophages.

METHODS

Immunoreactive amounts of IL-1ra or IL-1 beta were measured using ELISA. Changes in pulmonary function, sACE activity, and shadows on chest radiographs during observation periods were evaluated as markers of changes in disease activity.

RESULTS

We found that the patients whose shadows on chest radiographs showed improvement had a higher molar IL-1ra/IL-1 beta ratio than the patients whose shadows persistently remained 4 years after BAL examination (p < 0.05). The molar ratio was found to be positively correlated with improvement of percent vital capacity (p < 0.05) and negatively correlated with the ratio of sACE activity at the time of the last observation to sACE activity at the time of BAL (sACE(LAST)/sACE(BAL), p < 0.01). The sACE(LAST)/sACE(BAL) ratio was significantly lower in patients whose shadows on chest radiographs decreased than in those whose shadows remained unchanged (p < 0.005).

CONCLUSION

The IL-1ra/IL-1 beta ratio in the BAL fluid macrophage culture supernatants in patients with pulmonary sarcoidosis could be a useful marker in predicting the persistence of granulomatous lesions (chronicity).

Effects of interferons alpha and gamma on cytokine production and phenotypic pattern of human bronchial epithelial cells

Human bronchial epithelial cells are involved in airway immune mechanisms through secretion of cytokines and through cell-cell contacts with immunocompetent cells. The aim of our study was to assess the ability of interferon (IFN) alpha and gamma alone and in combination to modulate human bronchial epithelial cell (HBECs) release of the inflammatory cytokines IL-8 and IL-6 and fibronectin and to induce the surface expression of HLA-DR and ICAM-1 molecules involved in immune interactions with other cells. HBECs spontaneously secreted a limited amount of IL-8, which was significantly increased by IFN gamma. IFN alpha inhibited IFN gamma stimulated IL-8 secretion in a concentration-dependent manner. Further, IFN gamma induced IL-6 and fibronectin secretion, and this was also inhibited by IFN alpha. The expression of HLA-DR antigens was significantly increased by IFN gamma and partially inhibited by co-stimulation with IFN alpha. In contrast, IFN gamma also induced ICAM-1 expression by HBECs but co-stimulation with IFN alpha had no significant effect on the expression of this surface antigen. IFN alpha modulation of HBEC functions does not seem to be restricted to IFN gamma stimulation since either stimulatory or inhibitory effects of INF alpha on IL-8 production have been found in pilot experiments using IL-1 beta, TNF alpha, and TGF beta as stimuli. In summary, IFN-gamma induces a number of responses in HBECs including increased secretion of IL-6, IL-8 and fibronectin and increased expression of HLA-DR and ICAM-1. IFN alpha can inhibit all these except expression of ICAM-1 which is unaffected. IFN alpha can also interact with other inflammatory cytokines, but whether the effects are inhibitory or augmentive depends on the cytokines.

Functional cloning and mutational analysis of the human cDNA for phosphoacetylglucosamine mutase: identification of the amino acid residues essential for the catalysis

In Saccharomyces cerevisiae, phosphoacetylglucosamine mutase is encoded by an essential gene called AGM1. The human AGM1 cDNA (HsAGM1) and the Candida albicans AGM1 gene (CaAGM1) were functionally cloned and characterized by using an S. cerevisiae strain in which the endogenous phosphoacetylglucosamine mutase was depleted. When expressed in Escherichia coli as fusion proteins with glutathione S-transferase, both HsAgm1 and CaAgm1 proteins displayed phosphoacetylglucosamine mutase activities, demonstrating that they indeed specify phosphoacetylglucosamine mutase. Sequence comparison of HsAgm1p with several hexose-phosphate mutases yielded three domains that are highly conserved among phosphoacetylglucosamine mutases and phosphoglucomutases of divergent organisms. Mutations of the conserved amino acids found in these domains, which were designated region I, II, and III, respectively, demonstrated that alanine substitutions for Ser(64) and His(65) in region I, and for Asp(276), Asp(278), and Arg(281) in region II of HsAgm1p severely diminished the enzyme activity and the ability to rescue the S. cerevisiae agm1Delta null mutant. Conservative mutations of His(65) and Asp(276) restored detectable activities, whereas those of Ser(64), Asp(278), and Arg(281) did not. These results indicate that Ser(64), Asp(278), and Arg(281) of HsAgm1p are residues essential for the catalysis. Because Ser(64) corresponds to the phosphorylating serine in the E. coli phosphoglucosamine mutase, it is likely that the activation of HsAgm1p also requires phosphorylation on Ser(64). Furthermore, alanine substitution for Arg(496) in region III significantly increased the K(m) value for N-acetylglucosamine-6-phosphate, demonstrating that Arg(496) serves as a binding site for N-acetylglucosamine-6-phosphate.

Nilvadipine protects low-density lipoprotein cholesterol from in vivo oxidation in hypertensive patients with risk factors for atherosclerosis

OBJECTIVE

Nilvadipine, a calcium antagonist, has been shown to have antioxidant activity in vitro, but its effect on in vivo oxidation has not been assessed. The aim of this study was to investigate the antioxidant effect of this agent in vivo. The ratios of 7-keto cholestadien to cholesterol are believed to be an available marker of lipid peroxidation. Using these ratios, we have assessed the antioxidant effect of nilvadipine on low-density lipoprotein (LDL) in hypertensive patients with high risk of atherosclerosis. The risk factors of atherosclerosis may involve oxidation of LDL.

METHODS

Fifteen healthy subjects (seven females and eight males aged 35-72 years, mean +/- SD = 55.3 +/-13.8 years) and fifteen hypertensive patients (seven females and eight males aged 45-80 years, mean +/- SD = 60.2 +/- 11.8 years) were recruited. Patients were treated orally with nilvadipine (4 mg b.i.d.) for 4 weeks. Cholesterol oxidation levels of LDL in patients before and after nilvadipine therapy and healthy subjects were studied.

RESULTS

The ratios of 7-keto cholestadien to cholesterol in LDL of hypertensive patients before and 4 weeks after nilvadipine treatment and in healthy subjects were 6.5 +/- 1.6% (mean +/- SD), 3.8 +/- 1.2%, and 0.2 +/- 0.1%, respectively. There were significantly (P < 0.001) increased levels of cholesterol oxidation in LDL in patients with hypertension both before and after nilvadipine treatment compared with healthy subjects. However, there was a significantly (P < 0.001) decreased level of cholesterol oxidation in LDL in patients after nilvadipine treatment compared with patients before nilvadipine treatment.

CONCLUSION

Our data showed that nilvadipine may protect LDL cholesterol from in vivo oxidation in hypertensive patients with high risk of atherosclerosis.

Glucocorticoid-induced contractility and F-actin content of human lung fibroblasts in three-dimensional culture

Fibroblast contractility plays a useful role in the wound healing process but contributes to architectural distortion in the lungs. Glucocorticoids (GCs) have been reported to reduce dermal fibroblast contractility, which may result in delaying wound healing, but the effects on lung fibroblasts are unknown. In this study, we examined how human lung fibroblast contractility is altered in the presence of GCs. Lung fibroblast cell lines (n = 5) were established from normal parts of surgically resected lung tissue. The effects of GCs on contractility were investigated with a type I collagen gel contraction assay. Filamentous actin (F-actin) content was detected by confocal microscopy and measured with a fluorescent phalloidin binding assay. GCs augmented fibroblast contraction in a concentration-dependent manner, with an approximate EC(50) of 1.8 x 10(-8) M, whereas other steroid derivatives had no effects. GC contractility needed de novo protein synthesis. The GC-induced increase in contractility was found to be consistent with an increase in F-actin content. In conclusion, lung fibroblast contractility was enhanced with GCs through an upregulation of lung fibroblast F-actin.

Dicarboxylic acids as markers of fatty acid peroxidation in diabetes

Increased urinary excretion of dicarboxylic acids (DAs) has been well known in patients with diabetic ketoacidosis (DKA). It was known that small amounts of such DAs were also detected in urine from healthy humans. Upon chemical, radiation-induced or enzymatic oxidation, cis-polyunsaturated fatty acids (PUFA) have previously been shown to generate saturated short- and medium-chain length DAs. In diabetes, it was confirmed that the imbalance between the generation of free radicals and antioxidant defense systems increases oxidative stress and leads to the damage of lipid, which contains PUFA. Some peroxidation products of PUFA, such as malondialdehyde and conjugated diene, are generally known to be elevated in patients with diabetes. The present study was undertaken to determine if urinary excretion of DAs is elevated in diabetic patients without DKA. Urine samples from ten non-ketoacidotic patients with type 2 diabetes and ten healthy subjects were examined for DAs by combined gas chromatography and mass spectrometry with selected ion monitoring. The diabetic subjects had significantly (Psebacic acid. Being stable and easily detectable compounds, DAs may be considered potential markers of oxidative attack on PUFA in diabetes.

Roles of three histidine kinase genes in hyphal development and virulence of the pathogenic fungus Candida albicans

The pathogenic fungus Candida albicans harbors three histidine kinase genes called CaSLN1, CaNIK1, and CaHK1. The disruption of any one of these three genes impaired the hyphal formation and attenuated the virulence of C. albicans in a mouse systemic candidiasis model. The effects of the disruption on hyphal formation and virulence were most severe in the cahk1Delta null mutants. Although the double disruption of CaSLN1 and CaNIK1 was impossible, further deletion of CaSLN1 or CaNIK1 in the cahk1Delta null mutants partially restored the serum-induced hypha-forming ability and virulence. When incubated with radiolabelled ATP, the recombinant CaSln1 and CaNik1 proteins, which contained their own kinase and response regulator domains, were autophosphorylated, whereas CaHk1p was not. These results imply that in C. albicans, CaSLN1 and CaNIK1 function upstream of CaHK1 but are in distinct signal transmission pathways.

IL-4 and IL-13 stimulate human bronchial epithelial cells to release IL-8

Cytokine networks are important in regulating the traffic of inflammatory cells in the airways. Interleukin-8 (IL-8) released by human bronchial epithelial cells (HBECs) is thought to be of particular importance in attracting neutrophils and monocytes to sites of inflammation. Increased release of IL-8 by HBECs in response to Th-1 cytokines such as TNF alpha and IL-1 beta may be an important pathophysiologic pathway. The present study was designed to explore the role of the Th2 cytokine IL-4 and the functionally related interleukins IL-10, and IL-13 on the regulation of IL-8 release by HBECs. HBECs (passage 4-6) were cultured in LHC9/RPMI and when confluent cells were stimulated in unsupplemented medium LHCD/RPMI by IL-4, IL-10, and IL-13 at 10 ng/ml concentration for all cytokines. TNF alpha stimulation was used as a positive control. After 24 hours supernatants were collected and tested for IL-8 by a sandwich ELISA. Unstimulated HBECs spontaneously released limited amounts of IL-8 (11 +/-1 pM) and significantly increased cytokine production in response to IL-4 (42 +/- 1 pM), IL-13 (30 +/- 1 pM) and TNF (128 +/- 11 pM). Stimulation with IL-10 (11 +/- pM) did not change basal production of IL-8. When HBECs were co-stimulated with IL-4 plus TNF, the production of IL-8 was further increased (204 +/- 5 pM). In contrast, IL-10 attenuated the effect of TNF during co-stimulation (82 +/- 5 pM). IL-13 did not affect the release of IL-8 induced by TNF (111 +/- 9 pM). Northern blot analysis of IL-8 mRNA levels showed the highest induction of IL-8 mRNA in HBECs co-stimulated with TNF and IL-4. We conclude from our study that IL-4 directly induces IL-8 release from HBECs and amplifies the release of IL-8 in response to TNF alpha. IL-13 is less active and IL-10 has an inhibitory effect. Airway epithelial cells are able to interact, therefore, with products of both Th1 and Th2 cells with respect to modulating release of IL-8.

Th2-type cytokines modulate IL-6 release by human bronchial epithelial cells

The multifunctional cytokine IL-6, which can be locally produced by human bronchial epithelial cells (HBECs), has been found to play a role in IL-4 dependent IgE synthesis. Since the allergic reaction in bronchial asthma is associated with the upregulation of IL-4 and Th2 type of immune response, the purpose of our study was to assess whether IL-4 and related cytokines IL-10 and IL-13 regulate IL-6 release by HBEC s. HBECs were obtained by bronchial brushing, cultured in LHC-9/RPMI 1640. At the third passage the cells were stimulated with cytokines (0.1-20 ng/ml) diluted in unsupplemented media for 24 h. The supernatants were tested for IL-6 content by sandwich ELISA. Unstimulated HBECs produced detectable amounts of IL-6 (368+/-25 pg/ml). Exposure to IL-10 (368+/-22 pg/ml) and IL-13 (395+/-6 pg/ml) resulted in little changes. IL-4 caused a slight but significant increase in IL-6 release (530+/-45 pg/ml), P<0.05, TNFalpha (1657+/-85 pg/ml) and IFNgamma (1953+/-37 pg/ml) showed strong induction of IL-6 release in HBECs (P<0.005 and P<0.001, respectively). Both IL-4 and IL-13 significantly inhibited TNF induced IL-6 release (P<0.01 for both) while augmenting the effect of IFNgamma (P<0.005 and P<0.01, respectively.). IL-10 was without a significant effect. We conclude that Th2-type cytokines IL-4 and IL-13 affect the release of IL-6 by HBECs in response to TNFalpha (inhibition) and IFgamma (augmentation). IL-10 had no effect on the regulation of IL-6 release. Modulation of IL-6 levels by Th2-type cytokines may play a role in allergic reactions through the IL-6 promoting effect on IL-4 mediated IgE production.

Proinflammatory or regulatory cytokines released from BALF macrophages of healthy smokers

BACKGROUND

Chronic smoking influences bronchoalveolar lavage fluid (BALF) cell profiles in healthy subjects, which may alter profiles of inflammatory and regulatory cytokines.

OBJECTIVE

We focused on the evaluation of smoking-related changes in the amounts of cytokines released from BALF macrophages.

METHODS

We measured the amounts of immunoreactive culture supernatants by using ELISA.

RESULTS

The amounts of IL-1 receptor antagonist (IL-1ra) were lower in smokers [n = 10, median 22.1 ng/ml, 25th and 75th percentiles (18.7-39.1)] than in nonsmokers [n = 10, 48.6 (39.2-66.1), p = 0.010]. In smokers, lipopolysaccharide stimulation revealed decreases in the amounts of interleukin-6 (IL-6) [nonsmokers: 2.1 ng/ml (0.68-5.4 vs. smokers: 0.5 (0.03-0.87), p = 0.049] as well as IL-1ra [nonsmokers: 69.2 ng/ml (48.3-83.8) vs. smokers: 27.3 (17.2-56.7), p = 0.028]. A delay in release from intracellular storage was not the cause of the reduced amounts of IL-1ra. In addition, interleukin-1beta (IL-1beta) was positively correlated with IL-6 and granulocyte macrophage colony-stimulating factor in nonsmokers, but not in smokers. Furthermore, the decreases in IL-1ra and interleukin-8 were correlated with the increase in the number of BALF macrophages in smokers, but not in nonsmokers.

CONCLUSIONS

Chronic smoking caused changes in the profiles of cytokines released from BALF macrophages in healthy subjects. Decreases in the amounts of regulatory cytokines, but not prominent changes in the amounts of inflammatory ones, were characteristic.

Link between glycation and lipoxidation in red blood cells in diabetes

Oxidative stress is postulated to be increased in patients with diabetes mellitus. Glycation enhanced by elevated glucose concentrations may induce the formation of oxygen-derived free radicals (OFRs). OFRs would cause oxidative damage to endogenous molecules, including cholesterol. Accumulating evidence suggests that oxidative cell injury caused by OFRs contributes to the development of both macroangiopathy and microangiopathy in diabetes. Our previous studies have shown that 7-keto cholestadien is one of the major products of cholesterol peroxidation in diabetic erythrocyte membrane and its levels correlate with hemoglobin Alc (HbAlc) values. We have newly identified 3-cholesten-6-one, one of the minor products of cholesterol peroxidation, in it. The aim of our study is to investigate whether 3-cholesten-6-one levels also correlate with HbAlc values. Levels of 3-cholesten-6-one were assessed in erythrocyte membrane lipid by monitoring peak areas of 3-cholesten-6-one to cholesterol with gas chromatography-mass spectrometry. The peak area ratio of 3-cholesten-6-one to cholesterol was used as a marker of cholesterol peroxidation. The HbAlc value, an index of both glycemic stress and glycation, was measured by high-performance liquid chromatography. In this study, we evaluated 33 diabetic and 29 healthy subjects, matched for age (59.3+/-14.5 vs. 57.3+/-13.7 years, mean+/-S.D.) and sex (15 males and 14 females vs. 16 males and 17 females). There were both significantly raised HbAlc levels (4.6+/-0.8 vs. 8.3+/-2.4%, P<0.001) and significantly increased ratios of 3-cholesten-6-one to cholesterol (0.2+/-0.4 vs. 21+/-1.8, P<0.001) in diabetic patients compared to control subjects. A good correlation between HbAlc levels and ratios of 3-cholesten-6-one to cholesterol was found in participants (r = 0.75, P<0.001, y = 0.46x-1.8). This suggests that an oxidative stress exists in diabetes and the link between glycation and lipoxidation is found in diabetic red blood cell.

IL-4 induces ICAM-1 expression in human bronchial epithelial cells and potentiates TNF-alpha

Interleukin (IL)-4 is thought to contribute to the Th2 type of immune response and hence the development of allergic reactions such as asthma. In asthmatic patients, the airway epithelium expresses increased amounts of the cell surface adhesion molecule intercellular adhesion molecule (ICAM)-1 (CD54). One cytokine capable of inducing ICAM-1 in airway epithelial cells, tumor necrosis factor-alpha (TNF-alpha), is present in asthma. This study evaluated if IL-4 either alone or together with TNF-alpha costimulation might modulate CD54 expression by human bronchial epithelial cells (HBECs). CD54 positivity increased in response to IL-4 (16 +/- 2% positive vs. 3 +/- 1%, P < 0.01); greater induction of CD54 resulted from TNF-alpha (45 +/- 2%, P < 0.001). Costimulation with TNF-alpha plus IL-4 further augmented expression (56 +/- 1%, P < 0.05). Immunoperoxidase results were confirmed by flow cytometry. RT-PCR revealed no increase in ICAM-1 mRNA expression under control conditions or after stimulation with IL-4 alone. TNF-alpha increased IL-4 mRNA, and IL-4 potentiated this. Functionally, IL-4 augmented the adhesion of THP-1 monocyte/macrophage cells to monolayers of HBECs both alone and in the presence of TNF-alpha. We conclude that 1) IL-4 augments epithelial cell ICAM-1 expression, 2) IL-4 potentiates the adhesion of THP-1 monocyte/macrophage cells to epithelial cells, and 3) modulation of epithelial cell ICAM-1 expression by IL-4 may play a role in the immunopathology of bronchial asthma.

The number of interleukin 1 receptors on lung fibroblasts in patients with idiopathic pulmonary fibrosis

BACKGROUND

We investigated the expression of the IL-1 receptor on lung fibroblasts in patients with idiopathic pulmonary fibrosis (IPF) the histology of which was diagnosed as usual interstitial pneumonia.

METHODS

125I-labeled IL-1alpha bound to lung fibroblasts in a specific and saturable manner in lung fibroblasts obtained from both IPF patients and control subjects.

RESULTS

Scatchard plot analysis revealed a single type of binding site in both groups. In total, 8,600 +/- 1,450 (mean +/-SD) sites/cell with a dissociation constant (Kd) of 1.83 +/- 0.28 (mean +/-SD) nM in patients with IPF and 7,920 +/- 1,470 sites/cell with a Kd of 2.43 +/- 0.49 nM in control subjects were counted. Furthermore, affinity cross-linking experiments revealed that the IL-1 receptor on lung fibroblasts in patients with IPF and control subjects had a molecular size of 80 kD.

CONCLUSION

In conclusion, type I receptor was present on human lung fibroblasts, but there were no differences in number or affinity between IPF patients and controls.

Formation of 9-hydroxy linoleic acid as a product of phospholipid peroxidation in diabetic erythrocyte membranes

The increased production of oxygen-derived free radicals (OFR) and lipid peroxidation may contribute to vascular complications in diabetes. Some lipid peroxidation products have already been reported to be formed via glucose-induced oxidative stress. We have identified 9-hydroxy linoleic acid (9-OH-C18:2) in the red cell membrane phospholipid of diabetic subjects. We hypothesized that 9-OH-C18:2 would be formed in hydroxyl radical reactions to linoleic acid (C18:2) during glucose-induced oxidative stress, and confirmed that the formation of 9-OH-C18:2 was induced by ultraviolet (UV)-C irradiation to the synthetic C18:2. UV-C light generates highly reactive hydroxy radicals. C18:2 is confirmed to be the precursor of 9-OH-C18:2. To estimate the degree of oxidative damage to red cell membrane phospholipids, we developed a selective ion monitoring gas chromatography-mass spectrometric measurement for C18:2 and 9-OH-C18:2, following methanolysis of red cell membrane phospholipids. The relative peak height ratio of C18:2 to 9-OH-C18:2 (9-OH-C18:2/C18:2) was measured in phospholipid extracts of red cell membranes from healthy (n=29, 3.1+/-1.9%) and diabetic (n=27, 20. 9+/-16.1%) subjects. It was confirmed that 9-OH-C18:2/C18:2 is significantly (P<0.001) elevated in patients with diabetes. The measurement of 9-OH-C18:2/C18:2 in red cell membranes should be useful for assessing oxidative damage to membrane phospholipids in diabetes.

Angiotensin II receptor on BALF macrophages from Japanese patients with active sarcoidosis

BACKGROUND

Serum angiotensin converting enzyme (ACE) activity and its changes are important markers for disease activity in patients with sarcoidosis. We earlier reported that ACE and its enzymatic product, angiotensin II (A-II), might play a role in maintaining macrophage/T lymphocyte alveolitis by enhancing an accessory function of macrophages in chronic active cases with sarcoidosis.

AIM OF THE WORK AND METHODS

We examined whether A-II receptor is present on BALF macrophages by a receptor binding assay using 125I-labeled A-II, and by amplification of A-II receptor gene transcripts using RT-PCR methods and quantification of the amounts of transcripts by HPLC.

RESULTS

The receptor binding assay suggested that specific binding of A-II to BALF macrophages was somewhat more prevalent in active sarcoidosis than in controls. A specific band for A-II receptor was detected by RT-PCR. A-II receptor gene expression was standardized as the ratio to beta-actin. An increased ratio was shown in active sarcoidosis (0.70 +/- 0.19; n = 14) compared to inactive cases (0.14 +/- 0.06; n = 5; p = 0.023) and healthy subjects (0.15 +/- 0.09; n = 5, p = 0.029). The ratio correlated positively with the percentage of BALF T lymphocytes (r = 0.60, p = 0.0056), and negatively with BALF macrophages (r = 0.60, p = 0.0055). No difference was detected between nonsmokers and smokers.

CONCLUSION

The amounts of A-II receptor gene expression of BALF macrophages correlated with disease activity in patients with pulmonary sarcoidosis.

Glycated hemoglobin and lipid peroxidation in erythrocytes of diabetic patients

In diabetes, glycation and subsequent browning (or glycoxidation) reactions are enhanced by elevated glucose concentrations. It is unclear whether the diabetic state per se also induces an increase in the generation of oxygen-derived free radicals (OFRs). However, there is some evidence that glycation itself may induce the formation of OFRs. OFRs cause oxidative damage to endogenous molecules, including cholesterol. 7-Oxocholesterol is known to be one of the major products of cholesterol oxidation. The level of cholesterol peroxidation products was assessed in erythrocyte membrane lipid by monitoring the peak height ratio of 7-oxocholesterol, one of the products of cholesterol peroxidation, to cholesterol with gas chromatography/mass spectrometry (GC/MS). The peak height ratio of 7-oxocholesterol to cholesterol was used as a biomarker of lipid peroxidation. The hemoglobin A1c (HbA1c) value, an index of glycemic stress, was measured by high-performance liquid chromatography. We examined the relationship between the levels of cholesterol peroxidation products and HbA1c in erythrocytes of diabetic and healthy subjects. There was a significantly increased ratio of 7-oxocholesterol to cholesterol in diabetic erythrocytes compared with control erythrocytes. The ratio of 7-oxocholesterol to cholesterol was significantly correlated with the level of HbA1c. This suggests that glycation of hemoglobin via chronic hyperglycemia is linked to cholesterol peroxidation in erythrocytes of both diabetic and healthy subjects.

Saccharomyces cerevisiae GNA1, an essential gene encoding a novel acetyltransferase involved in UDP-N-acetylglucosamine synthesis

The Saccharomyces cerevisiae gene, YFL017C, for a putative acetyltransferase was characterized. Disruption of YFL017C was lethal, leading to a morphology similar to those caused by the depletion of AGM1 or UAP1, the genes encoding phospho-N-acetylglucosamine mutase and UDP-N-acetylglucosamine pyrophosphorylase, respectively. This implies the involvement of YFL017C in UDP-N-acetylglucosamine synthesis. The recombinant protein for YFL017C displayed phosphoglucosamine acetyltransferase activities in vitro and utilized glucosamine 6-phosphate as the substrate. When incubated with Agm1p and Uap1p, the Yfl017c protein produced UDP-N-acetylglucosamine from glucosamine 6-phosphate. These results indicate that YFL017C specifies glucosamine-6-phosphate acetyltransferase; therefore, the gene was designated GNA1 (glucosamine-6-phosphate acetyltransferase). In addition, whereas bacterial phosphoglucosamine acetyltransferase and UDP-N-acetylglucosamine pyrophosphorylase activities are intrinsic in a single polypeptide, they are encoded by distinct essential genes in yeast. When the sequence of ScGna1p was compared with those of other acetyltransferases, Ile97, Glu98, Val102, Gly112, Leu115, Ile116, Phe142, Tyr143, and Gly147 were found to be highly conserved. When alanine was substituted for these amino acids, the enzyme activity for the substituted Phe142 or Tyr143 enzymes was severely diminished. Although the activity of Y143A was too low to perform kinetics, F142A displayed a significantly increased Km value for acetyl-CoA, suggesting that the Phe142 and Tyr143 residues are essential for the catalysis.

The effect of probucol on oxidized cholesterol disposition in hyperlipidaemic patients

Probucol is a cholesterol-lowering and antioxidant drug that has been shown to inhibit or delay the progression of atherosclerosis. This antiatherosclerotic effect may result from the removal of oxidized cholesterol on the surface of low-density lipoprotein (LDL). To investigate whether probucol transfers oxidized cholesterol from LDL to urine, urine samples were obtained from five patients with hypercholesterolaemia treated with 500-mg probucol orally daily and from five healthy controls. Using gas chromatography-mass spectrometry, we identified cholesteryl-6-(2,6-di-tertiary butylphenol-4)-thioether (CT) in the urine samples from patients with hypercholesterolaemia but not from healthy controls. This result suggests that probucol is hydrolysed to form 4-mercapto-2,6-di-tertiary butylphenol (MBP) which conjugates with cholesterol-5 alpha, 6 alpha-epoxide, oxidized cholesterol, resulting in the formation of CT in vivo. In addition to its hypolipidaemic and antioxidant actions, probucol may act to prevent atherosclerosis by increasing the urinary excretion of oxidized cholesterol.