Quantitative Assessment of the Post-translational Modifications of Human Serum Albumin by Dimethyl Trisulfide

Some bacteria, such as Fusobacterium nucleatum, act as dimethyl trisulfide (DMTS) producers in the host in vivo. DMTS acts as a sulfane sulfur donor and chemically modifies the sulfhydryl groups. This study explored the post-translational modifications of human serum albumin using DMTS. Quantitative assessments were conducted on mixed disulfides of mercaptoalbumin with mercaptomethane (Alb-SS-CH3) and albumin hydropersulfide (Alb-SSH) as post-translationally modified species. The hydropersulfide group was alkylated with iodoacetamide, resulting in the formation of an albumin-mercaptoacetamide mixed disulfide. The mixed disulfides were subsequently reduced with tris(2-carboxyethyl)phosphine, and the liberated mercaptomethane and mercaptoacetamide were fluorescently labeled with 4-fluoro-7-sulfamoylbenzofurazan (ABD-F). Quantification was performed using HPLC with fluorescence detection. Using this methodology, we examined the formation of Alb-SS-CH3 and Alb-SSH via the reaction between 4% human serum albumin and DMTS at 10-100 µM concentrations. Approximately two molecules of Alb-SS-CH3 and one molecule of Alb-SSH were generated from one DMTS molecule. Moreover, hydrogen sulfide was identified as an intermediate, suggesting its generation and subsequent reaction with intraprotein disulfide bonds, leading to the production of Alb-SSH. These results suggest the production of DMTS in humans in vivo should be involved in the elevation of Alb-SS-CH3 and Alb-SSH contents in plasma samples.

Isomerization of Oxidized Linoleate Metabolites with trans/cis Conjugated Diene Moiety to Those with trans/trans One in the Lipoxygenase/Linoleate/Hydrogen Polysulfide System

Endogenous hydrogen polysulfides are radical scavengers, and the resulting thiyl radical may catalyze isomerization of the cis-double bond to a trans-double bond. This study examined whether oxidized linoleate species with trans/trans-conjugated diene moieties were generated in the 15-lipoxygenase/linoleate/hydrogen polysulfide system at a lower oxygen content. When 40 µL of 0.1 M phosphate buffer (pH 7.4) containing 1.0 mM linoleate, 1.0 µM soybean 15-lipoxygenase, and 100 µM sodium trisulfide was placed in a 0.6 mL polypropylene microtube for 1 h at 25 °C, the proportion of (E/E)-oxo-octadecadienoic acids (OxoODEs) content to the total OxoODEs content was estimated to be more than 80% (mol/mol). OxoODEs are generated through the pseudoperoxidase reaction of ferrous 15-lipoxygenase with hydroperoxy octadecadienoic acids (HpODEs), which are produced by the lipoxygenase reaction of ferric 15-lipoxygenase. The content of OxoODEs was positively correlated with the content of 9-HpODEs, indicating that 9-HpODEs production is involved in converting ferric 15-lipoxygenase to ferrous 15-lipoxygenase. Furthermore, when 40 µL of 0.1 M phosphate buffer (pH 7.4) containing 1.0 mM linoleate, 1.0 µM soybean 15-lipoxygenase, 100 µM sodium trisulfide, and nitroxyl radical (carbon-centered radical-trapping agent, 3-carbamoyl-2,2,5,5-tetramethyl-3-pyrrolin-N-oxyl (CmΔP)) was incubated in a 0.6 mL polypropylene microtube at room temperature, CmΔP-(E/Z)-ODEs were isomerized to CmΔP-(E/E)-ODEs in a time-dependent manner and this isomerization was inhibited by a radical scavenger, Trolox. The results indicate that thiyl radicals derived from hydrogen polysulfides isomerize trans/cis conjugated diene moiety to the trans/trans moiety.

2,2,6,6-Tetramethylpiperidine-1-oxyl acts as a volatile inhibitor of ferroptosis and neurological injury

Ferroptosis, a type of oxidative stress cell death, has been implicated in cell injury in several diseases, and treatments with specific inhibitors have been shown to protect cells and tissues. Here we demonstrated that a treatment with the nitroxide radical, 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), prevented the ferroptotic cell death in an airborne manner. Other TEMPO derivatives and lipophilic antioxidants, such as Trolox and ferrostatin-1, also prevented cell death induced by erastin and RSL3; however, only TEMPO exhibited inhibitory activity from a physically distant location. TEMPO vaporized without decomposing, and then dissolved again into a nearby water solution. Volatilized TEMPO inhibited glutamate-induced cell death in mouse hippocampal cell lines, and also reduced neuronal cell death in a mouse ischemia model. These results suggest that TEMPO is a unique cell protective agent that acts in a volatility-mediated manner.

Botanical sulfane sulfur donors inhibit ferroptotic cell death caused by the depletion of cysteine

Inhibitors against cystine-glutamate antiporter, including erastin, elicit ferroptotic cell death. The erastin-induced ferroptotic cell death appears to be caused by cysteine as well as glutathione depletion. Cysteine is an essential substrate for sulfane sulfur producing systems in cells, generating persulfides that function as intracellular antioxidants and intermediates in iron-sulfur cluster production. Therefore, we examined whether botanical sulfane sulfur donors such as diallyl trisulfide (DATS) and dimethyl trisulfide (DMTS) prevent ferroptotic cell death in HT1080 cells treated with erastin. As a result, DMTS (20 μM) and DATS (10 μM) rescued the erastin-treated HT1080 cells by 69.6% and 91.6%, respectively. Furthermore, DMTS-containing squeeze of cabbage (2.0 g/L) and DATS-containing squeeze of garlic (0.07 g/L) rescued the erastin-treated HT1080 cells by 76.5% and almost 100%, respectively. In conclusion, the ingestion of trisulfides may bring about increased resistance to ferroptotic cell death in vivo.

Lipoxygenase-mediated generation of lipid peroxides enhances ferroptosis induced by erastin and RSL3

In cancer cells the small compounds erastin and RSL3 promote a novel type of cell death called ferroptosis, which requires iron-dependent accumulation of lipid reactive oxygen species. Here we assessed the contribution of lipid peroxidation activity of lipoxygenases (LOX) to ferroptosis in oncogenic Ras-expressing cancer cells. Several 12/15-LOX inhibitors prevented cell death induced by erastin and RSL3. Furthermore, siRNA-mediated silencing of ALOX15 significantly decreased both erastin-induced and RSL3-induced ferroptotic cell death, whereas exogenous overexpression of ALOX15 enhanced the effect of these compounds. Immunofluorescence analyses revealed that the ALOX15 protein consistently localizes to cell membrane during the course of ferroptosis. Importantly, treatments of cells with ALOX15-activating compounds accelerated cell death at low, but not high doses of erastin and RSL3. These observations suggest that tumor ferroptosis is promoted by LOX-catalyzed lipid hydroperoxide generation in cellular membranes.

Thermoelectric Properties of AgBiTe2-Ag2Te Composite

We prepared composite materials of AgBiTe2 with several contents of Ag2Te small-size grains for applications to thermoelectric devices. By enhancing long-wavelength phonon scattering at the grain boundaries, lattice thermal conductivity (thermal conductivity due to lattice vibrations) decreased 30% and thus the thermoelectric characteristics were significantly improved.

New lesions detected by intraoperative ultrasound during liver resection for hepatocellular carcinoma

During liver resection for hepatocellular carcinoma (HCC), it is not uncommon for examinations by intraoperative ultrasound (IOUS) to detect small new lesions that were not found by preoperative examinations. Although a differential diagnosis is critical, it has not yet been established if IOUS is useful for this purpose with such small lesions. A total of 90 new lesions detected by IOUS in 79 liver resections were analysed. IOUS was performed on all of these cases and the features were recorded. The histologic characteristics of these 90 new lesions were checked by needle biopsy and their relations to the clinical data were analyzed. The IOUS pattern of the lesion was hypoechoic in 36 cases, hyperechoic in 49 and mosaic in 5. A total of 24 HCC lesions were detected and the incidences of malignancy for each type were 30.6%, 18.4% and 80.0%, respectively. Multiple regression analysis revealed that the IOUS features of the new lesions were the only significant factors in predicting the histology. IOUS should be mandatory in liver resection for HCC because it is useful for finding new lesions and might contribute to prediction of the histologic features.

Antioxidant activity and xanthine oxidase inhibition activity of reductic acid: ascorbic acid analogue

Reductic acid (2,3-dihydroxy-2-cyclopentenone, 1) decreased the ESR signal of 5,5-dimethyl-1-pyrroline 1-oxide (DMPO)-OH produced by hydroxyl radical and DMPO. 1 also inhibited lipid peroxidation initiated by cytochrome P450 and tert-butyl hydroperoxide. 1 inhibited xanthine oxidase activity, while ascorbic acid and 2-hydroxytetronic acid, an ascorbic acid analogue without side chain, did not.

Alteration in the D-amino acid content of the rat pineal gland under anesthesia

In a previous report (Hamase, K. et al., Biochim Biophys Acta 1134: 214-222 (1997)), we showed that the rat pineal gland contains D-leucine (D-Leu) as well as D-aspartic acid (D-Asp). In this communication we report alterations in the content of these D-amino acids during anesthesia. The D-Asp content was significantly increased from 2.8 to 5.0, 4.8 and 5.8 nmol/pineal gland by administration of ether, urethane and pentobarbital, respectively. In contrast, the D-Leu content was decreased by administration of urethane or pentobarbital. The D-Leu content decreased from 4.2 to 2.2 pmol/pineal gland 4 hours after administration of urethane, although the content remained unchanged until 1.5 hours after administration. The content of the L-enantiomers of these amino acids were not affected by anesthesia. The urethane-induced decrease in D-leucine content was almost completely suppressed by a beta-agonist, (-)-isoproterenol, whereas the agonist itself had no effect.

D-aspartate uptake into cultured rat pinealocytes and the concomitant effect on L-aspartate levels and melatonin secretion

Significant amounts of D-aspartate (Asp) are found in mammalian tissues and D-Asp is presumed to play some significant, but as yet undefined physiological role. However, it is not known whether D-Asp is synthesized in mammals. In this study, we addressed this issue in cultured rat pinealocytes, parenchymal cells of the pineal gland, which contain significant amounts of D-Asp. Biosynthesis of D-Asp was found to be minimal to non-existent in cultured rat pinealocytes. We then investigated the mechanism of uptake of D-Asp into these cells and its consequent effect on cell function. D-Asp was efficiently taken up into cells, in a time- and dose-dependent manner. Interestingly, the L-Asp levels in the cells and media decreased concomitantly with the uptake of D-Asp. This decrease was not due to D-Asp cytotoxicity, since the cellular levels of othernted. D-Serine and D-alanine were not taken up efficiently into the cells and the cellular levels of L-serine and L-alanine were unchanged. Also, immunocytochemical staining with anti-D-Asp antibody showed that D-Asp, which had been taken up into the cells, was dispersed throughout the cytoplasm. In response to norepinephrine stimulation, pinealocytes, which had been pretreated with D-Asp released D-Asp as well as L-Asp. In these cells, norepinephrine-induced secretion of melatonin, a pineal hormone, was suppressed. The mechanism of this suppression is discussed here.

[Effect on 5'-deoxy-5-fluorouridine (5'-DFUR) of pyrimidine nucleoside phosphorylase (PyNPase), matrix metalloprotease and serum IAP values. Hokuriku Colorectal Cancer Chemotherapy Study Group]

PyNPase activity, MMPs activity and serum IAP values were measured in tumor tissues from colorectal cancer patients who had been divided into two groups, one given preoperative 5'-DFUR and the controls. PyNPase activity of the preoperative administration group was approximately equivalent to that of the controls. In the control group, correlations were assessed between PyNPase activity and activities of MMP1 and MMP3. To assess the effect of 5'-DFUR on the activity of MMPs, we divided patients into two groups, a high and a low PyNPase activity group. Although there was no correlation with MMPs activity of the preoperative administration group and the control group in the low PyNPase activity group, the activities of MMP1 and MMP9 of the control group were significantly higher in the high PyNPase activity group. Moreover, the serum IAP value of the administration group was significantly lower than that of the control group. These results indicated that PyNPase activity was thus suggested to be somehow related to MMPs activity and serum IAP values.

Regional distribution and postnatal changes of D-amino acids in rat brain

Regional distribution of D-amino acids in rat brain was studied by the modified highly sensitive analytical method which was previously developed. The method includes fluorogenic derivatization of each amino acid, isolation of each amino acid by reverse-phase HPLC, followed by enantiomeric separation with Pirkle-type chiral stationary phases. D-Amino acid contents were determined in the cerebrum, cerebellum, hippocampus, medulla oblongata, pituitary gland and pineal gland. D-Aspartic acid was observed in the pineal gland (3524 +/- 263 nmol/g, data are for male rats of 6 weeks of age) and the pituitary gland (80.5 +/- 9.0 nmol/g). D-Serine was found in various regions of the brain except for the cerebellum and medulla oblongata. D-Alanine was observed exclusively in the pituitary gland (25.9 +/- 4.4 nmol/g), whereas D-leucine was found in the pineal gland (3.4 +/- 0.4 nmol/g) and the hippocampus (1.6 +/- 0.07 nmol/g). No other D-amino acids were detected in the brain. The contents of D-aspartic acid in the pituitary gland and D-serine in the pineal gland were higher in female rats. In contrast the contents of D-alanine in the pituitary gland and D-leucine in the pineal gland and the hippocampus were higher in males. Postnatal changes of D-aspartic acid and D-leucine in the pineal gland and D-alanine in the pituitary gland were also investigated. The results described in this paper suggested that distinct regulatory mechanisms exist for individual D-amino acids in the corresponding region of rat brain.

[Prevalence of urinary incontinence among institutionalized persons aged 60 and over in Japan]

In order to estimate the prevalence of persons experiencing urinary incontinence among the institutionalized aged 60 and over in Japan, a questionnaire survey was conducted in 16 prefectures in February 1991. The questionnaires were distributed and collected by the nurses in hospitals and in other facilities. A total of 10,022 residents were asked to answer a questionnaire on their urinary incontinence condition and 9,798 responses were analysed. The main results were as follows; 1) The prevalence rate of urinary incontinence occurring almost daily in hospitalized persons aged 60 and over was 23.3% for men, 23.8% for women. 2) The prevalence rate of urinary incontinence occurring almost daily in institutionalized persons aged 60 and over in special nursing homes was 64.2% of the aged 60 and over for men, 67.9% for women. 3) The prevalence of urinary incontinence increased with age for both sexes especially in hospitalized persons. 4) The 95% confidence interval estimate for the number of the hospitalized over 60 years old suffering from almost daily urinary incontinent incidents was estimated to be from 31,000 to 113,000 in men and from 60,000 to 182,000 in women. 5) The 95% confidence interval estimate for the number of the institutionalized in special nursing home over 60 years old suffering from almost daily urinary incontinent incidents was estimated to be from 34,000 to 50,000 in men and from 97,000 to 119,000 in women. 6) The 95% confidence interval estimate for the number of the institutionalized over 60 years old suffering from almost daily urinary incontinent incidents was estimated to be from 318,800 to 570,600 in both sexes. 7) A random sampling survey is required to elucidate the actual state of prevalence in all generations. 8) Future research should emphasize the assessment of preventive and medical interventions, as incontinence is preventable and medical and surgical treatment options are available.

[Prevalence estimation of urinary incontinence among non-institutionalized persons aged 60 and over in Japan]

In order to estimate the total number and the prevalence rate of persons experiencing urinary incontinence among the non-instutionalized, aged 60 and over in Japan, a questionnaire survey was conducted in 16 prefectures in December 1991. The questionnaires were distributed and collected by public health nurses in Health Centers. A total of 12,180 questionnaires were administered. There were 11,528 responses (response rate of 94.6%), of which 11,142 were analysed. The main results were follows; 1) Daily urinary incontinence occurred in approximately 4.1% of the men and 5.3% of the women living at home. 2) 6.2% of the men and 8.9% of the women living at home had regular urinary incontinence with at least one episode of leakage per month in the preceding 12 months. 3) The prevalence of urinary incontinence increased with age for both sexes. 4) The 95% confidence interval estimate for the number of non-institutionalized persons over 60 years old suffering from urinary incontinent incidents nearly daily was estimated to be from 305,000 to 351,000 in men and from 554,000 to 675,000 in woman. 5) The 95% confidence interval estimate for the number of non-institutionalized persons over 60 years old with urinary incontinence of at least one episode of leakage per 5 months was from 3,507,000 to 3,889,000 for both sexes. 6) In order to determine age-specific prevalence for urinary incontinence for all age groups, a sampling survey is needed. 7) Research emphasizing the assessment of preventive interventions necessary since incontinence is preventable and medical and surgical treatment options are available.

Histology of the lens in the Weill-Marchesani syndrome

The Weill-Marchesani syndrome is a rare systemic connective tissue disease characterised by small stature, brachydactyly, ectopia lentis, and spherophakia. Three siblings with typical manifestations of this syndrome were reported. The ophthalmological findings in all these cases were spherophakia, severe myopia, a shallow anterior chamber, and narrow angle glaucoma. Two cases underwent laser iridotomy and drug treatment. In the third case the lens was removed from the eye because of injury, and this lens was examined by light and electron microscopy.

[Participation of regional inhabitants in cancer screening]

As part of the strategic planning for increasing participation by community residents in cancer screening, a survey about life style and attitudes toward cancer screening was carried out in Samukawa town, Kanagawa Prefecture. Subjects were males 40 years old or over, and females 30 years old or over selected by random sampling from residents. Number of subjects was 1,916 (822 males, 1,094 females). Self administered anonymous questionnaires were sent and returned by mail. The response rate was 73%. The results were as follows: (1) The reported participation rates for cancer screening under "the Health and Medical Services Law for the Aged" did not reflect the actual participation rate of residents. (2) The major reason for not participation in screening was lack of interest in cancer prevention. (3) Socio-economic status of regular participants in screening was different from persons who did not participate. (4) Persons who did not participate in screening were more passive with regard to obtaining knowledge of cancer than regular participants. (5) Results of this study show that cancer prevention education at various levels such as by clinical offices, TV and radio programs, and newspapers may be effective. In order to increase participation in screening programs, health education that considers the life style characteristics of persons who do not participate in the screening programs is vitally important.

[Screening for colorectal cancer based on our experience with early colorectal cancer and adenoma]

In order to establish method of screening for colorectal cancer, we studied clinicopathological features in 116 cases of adenoma, precancerous lesion, and in 80 cases of early colorectal cancer. The incidence of early cancer began to rise at the age of more than 40, reaching a peak in the sixth decade. The risk for men was higher than for women. In relation to the location of these lesions, 71% of the adenoma and 91% of the early cancer were in the left colon and rectum. As symptoms on admission, overt bleeding from the rectum appeared in 35% of the adenoma and in 56% of the early cancer patients, respectively. Therefore, we emphasize that it is extremely important to examine overt and occult bleeding as the first screening for colorectal cancer.