Changes in homocysteine and non-mercaptoalbumin levels after acute exercise: a crossover study

BACKGROUND

Acute exercise is one factor that increases blood homocysteine levels, and elevated homocysteine levels cause oxidative stress. Albumin, which is abundant in blood, is an antioxidant, and the redox state of albumin is used as an index of oxidative stress in blood. This study aimed to assess the effect of acute exercise on plasma homocysteine levels and the blood non-mercaptoalbumin/mercaptoalbumin ratio as an oxidative stress marker.

METHODS

This study used a crossover design with exercise and control conditions. Under exercise conditions, a bicycle ergometer was used to perform 40 min of transient constant-load exercise at 65% heart rate reserve. Under control conditions, participants rested for 40 min. Blood was collected before, 30 min after, and 90 min after exercise, and at the same time points under control conditions. Samples were analyzed for the homocysteine concentration and non-mercaptoalbumin/mercaptoalbumin ratio.

RESULTS

The results revealed that a 65% heart rate reserve and 40 min of acute exercise increased plasma homocysteine concentration and non-mercaptoalbumin ratio. In the intra-condition comparison, the plasma Hcy concentration was significantly increased at Post 30 min (+ 0.83 ± 0.70 µmol/L, P = 0.003) compared with that at Pre in the exercise condition. Furthermore, 90 min after exercise, the blood non-mercaptoalbumin ratio was significantly increased (+ 0.35 ± 0.71%, P = 0.030) compared to Pre.

CONCLUSION

These results indicate that the plasma Hcy concentration first increased, and then the non-mercaptoalbumin/mercaptoalbumin ratio increased as the elevated state was maintained. This study revealed that 65% heart rate reserve, 40 min of acute exercise increased plasma Hcy concentration and non-mercaptoalbumin ratio.

Effect of Acute Dietary Nitrate Supplementation on the Venous Vascular Response to Static Exercise in Healthy Young Adults

The purpose of this study was to test the hypothesis that acute intake of inorganic nitrate (NO3−) via supplementation would attenuate the venoconstriction and pressor response to exercise. Sixteen healthy young adults were assigned in a randomized crossover design to receive beetroot juice (BRJ) or an NO3−-depleted control beverage (prune juice: CON). Two hours after consuming the allocated beverage, participants rested in the supine position. Following the baseline period of 4 min, static handgrip exercise of the left hand was performed at 30% of the maximal voluntary contraction for 2 min. Mean arterial pressure (MAP) and heart rate (HR) were measured. Changes in venous volume in the right forearm and right calf were also measured using venous occlusion plethysmography while cuffs on the upper arm and thigh were inflated constantly to 30−40 mmHg. The plasma NO3− concentration was elevated with BRJ intake (p < 0.05). Exercise increased MAP and HR and decreased venous volume in the forearm and calf, but there were no differences between CON and BRJ. Thus, these findings suggest that acute BRJ intake does not alter the sympathetic venoconstriction in the non-exercising limbs and MAP response to exercise in healthy young adults, despite the enhanced activity of nitric oxide.

CHEMORESISTANCE RELATED TO HYPOXIA ADAPTATION IN MESOTHELIOMA CELLS FROM TUMOR SPHEROIDS

BACKGROUND

Hypoxia has been noted as a key factor for induction and maintenance of cancer stemness thereby leading to therapy resistance. Three-dimensional (3D) spheroid models demonstrate a heterogeneity of hypoxic regions replicating the in vivo situation within tumors. Utilizing an established 3D spheroid model, we investigated whether extrinsic hypoxia reinforced chemoresistance in malignant pleural mesothelioma (MPM) spheroids.

MATERIALS AND METHODS

Tumor spheres were generated from Meso-1 (a typical human MPM cell line) cells having high spheroid-forming ability. To induce hypoxia condition, we utilized a hypoxia chamber with regulation of O2 and CO2 levels. Cell viability was estimated by a WST-8 assay. Real-time polymerase chain reaction and Western blot were performed to evaluate the expression at mRNA and protein levels.

RESULTS

Compared with cells cultured in the two-dimensional monolayer model, tumor sphere cells showed elevated mRNA levels of cancer stemness markers (CD26, CD44 and ABCG2) and protein levels of the stemness and hypoxia adaptation markers (ABCG2, ALDH1A1 and HIFs). Correlating with this, 3D spheroid cells were more resistant to permetrexed and topotecan than the two-dimensional cells, indicative of their potential for hypoxic adaptation. Furthermore, significantly stronger resistance to both chemotherapeutic agents was observed in spheroid cells upon hypoxic challenge compared to spheroid cells under normoxia.

CONCLUSION

From the present data, it is concluded that hypoxia adaptation of MPM cells from tumor spheres could enhance their chemoresistance.

Acute dietary nitrate supplementation does not change venous volume and compliance in healthy young adults

In this randomized single-blind, placebo-controlled, crossover study, we investigated the influence of inorganic nitrate (NO₃^-) supplementation on venous volume and compliance in the resting forearm and calf. Twenty healthy young adults were assigned to receive an NO₃^--rich beverage (beetroot juice [BRJ]: 140 mL; ~8 mmol NO₃^-) or an NO₃^¯-depleted control beverage (prune juice [CON]: 166 mL; < 0.01 mmol NO₃^-). Two hours after consuming the allocated beverage, each participant rested in the supine position for 20 min. Cuffs were then placed around the right upper arm and right thigh, inflated to 60 mmHg for 8 min, and then decreased to 0 mmHg at a rate of 1 mmHg/s. During inflation and deflation of cuff pressure, changes in venous volume in the forearm and calf were measured by venous occlusion plethysmography. Venous compliance was calculated as the numerical derivative of the cuff pressure‒venous volume curve in the limbs. The plasma NO₃^- concentration was elevated by intake of BRJ (before, 15.5 ± 5.8 µM; after, 572.0 ± 116.1 µM, P < 0.05) but not by CON (before, 14.8 ± 7.2 µM; after, 15.3 ± 7.4 µM, P > 0.05). On the other hand, there was no significant difference in venous volume or compliance in the forearm or calf between BRJ and CON. These findings suggest that although acute inorganic NO₃^- supplementation may enhance the activity of nitric oxide (NO) via NO₃^- → nitrite → NO pathway, it does not influence venous volume or compliance in the limbs in healthy young adults.

A Redox-Silent Analogue of Tocotrienol May Break the Homeostasis of Proteasomes in Human Malignant Mesothelioma Cells by Inhibiting STAT3 and NRF1

6-O-Carboxypropyl-alpha-tocotrienol (α-T3E) is a multi-target redox-silent analogue of tocotrienol that exhibits cytotoxicity against many cancer cells, including malignant mesothelioma (MM) cells. α-T3E has several molecular targets to effectively induce cytotoxicity against MM cells; however, the mechanisms underlying this cytotoxicity remain unclear. In the present study, we demonstrated that the α-T3E-dependent disruption of the homeostasis of proteasomes strongly induced endoplasmic reticulum (ER) stress, which resulted in effective cytotoxicity against MM cells. The α-T3E-dependent disruption of the homeostasis of proteasomes depended on decreases in proteasome subunits via the inactivation of signal transducer and activator of transcription 3 (STAT3) and nuclear factor erythroid 2 related factor-1 (NRF1), which inhibited protease activity, such as chymotrypsin-like activity, in proteasomes. The α-T3E-dependent inhibition of this activity also induced severe ER stress and ultimately resulted in effective cytotoxicity against MM cells with chemoresistance. The present results indicate that α-T3E acts as an effective anti-mesothelioma agent by disrupting the homeostasis of proteasomes through the simultaneous inactivation of STAT3 and NRF1.

How elevated CO2 affects our nutrition in rice, and how we can deal with it

Increased concentrations of atmospheric CO2 are predicted to reduce the content of essential elements such as protein, zinc, and iron in C3 grains and legumes, threatening the nutrition of billions of people in the next 50 years. However, this prediction has mostly been limited to grain crops, and moreover, we have little information about either the underlying mechanism or an effective intervention to mitigate these reductions. Here, we present a broader picture of the reductions in elemental content among crops grown under elevated CO2 concentration. By using a new approach, flow analysis of elements, we show that lower absorption and/or translocation to grains is a key factor underlying such elemental changes. On the basis of these findings, we propose two effective interventions-namely, growing C4 instead of C3 crops, and genetic improvements-to minimize the elemental changes in crops, and thereby avoid an impairment of human nutrition under conditions of elevated CO2.

Improvement of serum zinc levels in young Japanese women by provision of food information

We investigated whether or not an intervention of providing food information improves serum Zn levels in ninety-two 18-20-year-old Japanese women. The mean serum Zn level of the participants was 73.09 ± 10.56 (mean ± SD) μg/dL, where 79 % of the participants had lower than the reference Zn level (80 μg/dL) proposed by the Japan Society for Biomedical Research on Trace Elements. Participants were divided into food information (INF) group, supplement (SPL) group, and control (C) group, and their serum Zn levels were measured before and after 2 weeks of intervention. The results showed that changes in serum Zn levels were (expressed in μg/dL): 71.23 ± 8.42 to 76.83 ± 12.22 in INF group (NS; not significant), 72.72 ± 10.77 to 84.07 ± 12.03 in SPL group (P < 0.01), and 72.69 ± 9.46 to 74.52 ± 11.44 in C group (NS). Percentage of normal subjects in serum Zn level (>79 mg/dL) were significantly increased in INF group (16.7 to 40%, P < 0.05) and SPL group (17.2 to 69%, P < 0.001) by each intervention. Food information only entailed a table of food items with high Zn content (card-type) and Zn intake menu (recipes). The results suggested that providing food information is effective in improving latent low Zn in young Japanese women.

Genotoxic effects of N-nitrosoketamine and ketamine as assessed by in vitro micronucleus test in Chinese hamster lung fibroblast cell line

OBJECTIVES

Ketamine hydrochloride (KT) is a secondary amine that has been safely used as an injectable anesthetic and analgesic to avoid the production of nitroso compounds in the stomach. However, ketamine in the tablet form has recently become an abused, recreational drug. The aim of this study was to investigate the genotoxic effects of N-nitrosoketamine (NKT) and KT on the basis of an in vitro micronucleus (MN) test using a Chinese hamster lung fibroblast cell line (CHL/IU).

METHODS

NKT was synthesized from KT in our laboratory. In the MN tests, CHL/IU cells were continuously treated with either NKT or KT for 24, 48, or 72 hours without the S9 mix. The cells were also treated with NKT or KT with or without the S9 mix for 6 hours, followed by a recovery period of 18, 42, or 66 hours (short-term treatment). The results were considered to be statistically significant when the p-values of both Fisher's exact test and the trend test were less than 0.05.

RESULTS

After the short-term treatment with either NKT or KT with and without the S9 mix, the frequency of micronuclei significantly increased. However, the frequency of micronuclei did not significantly increase after the continuous treatment with either NKT or KT. Both NKT and KT were determined to be genotoxic in the short-term treatment with or without the S9 mix, but they were determined to be nongenotoxic in continuous treatment.

CONCLUSION

Our findings suggest that NKT has a stronger genotoxic effect than KT.

[Occupational poisoning and biological exposure monitoring]

Biological exposure monitoring is available for detecting occupational toxic chemicals. It is possible to evaluate the exposure and adverse effects induced such the occupational toxic chemicals with biological exposure monitoring. It is used in health examination, for the recommendation of occupational exposure limits based on biological exposure monitoring, and for biological exposure indices of the American Conference of Governmental Industrial Hygienists (ACGIH).

Geonotoxicity study of illegal drug MDMA and its nitroso derivative N-MDMA by micronucleus and chromosomal aberration tests using Chinese hamsger lung fibroblast cell line

OBJECTIVES

An increase in incidence of the illegal use of tablets containing 3,4-methylenedioxymethamphetamine hydrochloride (MDMA) has recently become a widespread social problem. MDMA ingested orally reacts with nitrite in the stomach and is synthesized intoN-nitroso-3,4-methylenedioxymethamphetamine (N-MDMA). The aim of this study is to investigate the genotoxic effects of MDMA and N-MDMA on the basis of the results of an in vitro micronucleus (MN) test and an in vitro chromosomal aberration (CA) test using a Chinese hamster lung fibroblast cell line (CHL/IU).

METHODS

Tablets containing MDMA obtained from the Regional Bureau of the Ministry of Health, Labor and Welfare were purified, and N-MDMA was synthesized from MDMA in our laboratory. To evaluate the effects of MDMA and N-MDMA, the MN test established by our laboratory and the CA test in accordance with the guidelines for toxicity studies of drugs recommended by the Ministry of Health, Labor and Welfare were performed.

RESULTS

In the MN test, no increased frequency of MNs was not found for MDMA. On the other hand, an apparently increased frequency of MNs was observed for N-MDMA. In the CA test, no CA was found for MDMA, but CA was observed for N-MDMA apparently.

CONCLUSION

N-MDMA genotoxicity was observed in the MN and CA tests. However, no MDMA genotoxicity was observed.

The frequencies of micronuclei induced by cisplatin in newborn rat astrocytes are increased by 50-Hz, 7.5- and 10-mT electromagnetic fields

OBJECTIVES

Epidemiological studies have suggested that exposure to environmental and occupational electromagnetic fields (EMFs) contribute to the induction of brain tumors, leukemia, and other neoplasms. The aim of this study was to investigate the genotoxic effects of exposure to 50-Hz EMFs. and of co-exposure to cisplatin, a mutagen and carcinogen, and 50-Hz EMFs, using an in vivo newborn rat astrocyte micronucleus assay.

METHODS

Three day-old male Sprague-Dawley rats were co-exposed to 50-Hz EMFs and 1.25 or 2.5 mg/kg of cisplatin. Brain cells were dissociated into single cells and cultured for 96 hours, then stained with acridine orange and an antibody against glial fibrillary acidic protein. The frequency of micronucleated astrocytes was counted with a fluorescent microscope.

RESULTS

The frequency of micronuclei was not increased in rat astrocytes exposed to EMFs alone. However, the frequencies of micronuclei in co-exposure to 2.5 mg/kg cisplatin and EMFs (7.5- and 10-mT) were significantly increased, compared with those in exposure to 2.5 mg/kg cisplatin alone (sham-exposure, 0-mT EMFs) for 72 hours (p<0.01).

CONCLUSION

Exposure to EMFs alone did not have a genotoxic effect but co-exposure to EMFs increased the genotoxic activity induced by cisplatin. Our findings suggest that EMFs enhance the genotoxic effects of cisplatin.

[Design and development of one-handed denture brush for bedridden people]

Oral care for elderly bedridden people is one of the most necessary forms of care, not only for prevention of oral infection or aspiration pneumonia, but also in order to savor the taste of food and to recover and maintain mental vitality through the improvement in oral function. We designed denture brush that can be handled with one-hand in order to support independence. People require cooperation between medical treatment, health, and welfare services. We introduced the newly designed denture brush as a means to support the improvement of QOL for elderly bedridden people, and we hope to see the spread and promotion of oral care.

Micronucleus test using cultured new born rat astrocytes

Micronuclei is induced in cytoplasm as a consequence of the formation of chromosomal fragments or remaining chromosomes during cell division by the cause of clastogens or spindle poisons, and is used as an indicator of genotoxicity screening tests. There are few short-term genotoxicity screening tests using brain cells. We attempted to establish a new in vitro micronucleus test (MN test) system by use of central nervous system cells. Primary cultured astrocytes were prepared from newborn male Sprague-Dawley (SD) rats. In growth curve of astrocytes, doubling time was determined to be 31 h. In time study, the highest frequency of micronuclei was observed at 48 h, 72 h and 6 h-exposure-66 h-recovery by vincristine (VCR), mitomycin C (MMC) without metabolic activation system and cyclophosphamide (CPM) with metabolic activation system, respectively. Dose-response relationships between micronucleus frequency and concentrations of MMC, VCR and CPM were observed, respectively. It is suggested that the in vitro MN test using new born rat-astrocytes could be used as a screening test of environmental and occupational genotoxic chemicals in the central nervous system cells.

Mutagenicity of p-aminophenol in E. coli WP2uvrA/pKM101 and its relevance to oxidative DNA damage

It was recently reported that p-aminophenol (p-AP) induces DNA cleavage in mouse lymphoma cells, CHO cells and human lymphoblastoid cells. The mutagenicity of p-AP has not, however, been detected by reverse mutation assays. The purpose of this study was to assess the mutagenicity of p-AP by reverse mutation assay using Escherichia coli WP2uvrA/pKM101, which has a spectrum for detecting mutations different from those of other strains in the family with an AT base pair at the mutation site and has higher sensitivity to certain oxidative mutagens as compared to other strains. We found that p-AP was mutagenic to E. coli WP2uvrA/pKM101. The mutagenic activity of this compound was suppressed with the addition of dimethylsulfoxide or catalase, suggesting the involvement of active oxygen species in the mutagenic process induced by p-AP. To further elucidate the underlying mechanism, we used isolated DNA for the following experiments. It was revealed, by gel electrophoretic analysis, that p-AP induced DNA cleavage in the presence of Fe(III). However, p-AP alone did not induce this cleavage. Formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine by p-AP in calf thymus DNA was also detected in the presence of Fe(III) by HPLC with an electrochemical detector. ESR-spin trapping experiments using DMPO detected the production of hydroxyl radical (.OH) in the solution of p-AP with Fe(III). Both p-AP mediated DNA damages and .OH production by p-AP in the presence of Fe(III) were completely inhibited by .OH scavengers (ethanol, mannitol, sodium formate, dimethylsulfoxide) and catalase. These results suggest that .OH derived from the reaction between H2O2 and Fe(III) (Fenton reaction) participates in the oxidative DNA damage. Accordingly, the same mechanism might be working in E. coli WP2uvrA/pKM101 during induction of the mutation by p-AP.

Enhancement of lipid peroxidation in the liver of mice exposed to magnetic fields

To elucidate the biological effect of static magnetic fields (SMF), we measured lipid peroxidation in the liver, kidneys, heart, lungs and brain of mice exposed to SMF and also evaluated the combined effect of SMF exposure on the hepatotoxicity induced by treatment with carbon tetrachloride (CCl4). Lipid peroxidation in the liver was significantly increased by exposure to 4.7 T of SMF for 3, 6, 24, or 48 h, whereas that in the kidneys, heart, lungs and brain was not changed compared to the control. The combination of CCl4 injection and SMF exposure caused an increase in lipid peroxidation in the liver exceeding that caused by either treatment alone. Furthermore, the increase in activities of both GOT and GPT caused by CCl4 administration were also enhanced by SMF exposure. These results indicate that the exposure to strong SMF induces lipid peroxidation in the liver of mice and enhances the hepatotoxicity caused by CCl4 administration.

[Follow-up study of vestibular neuronitis]

A follow-up study of 26 patients with vestibular neuronitis is reported. The disease is characterized by an acute attack of severe vertigo with complete loss of unilateral caloric response. The following results were obtained: 1) The average period of spontaneous nystagmus was 136 days and the standard error was 39 days. 2) No correlation could be found between age and the period of spontaneous nystagmus. 3) Six patients showed direction reversal in their spontaneous nystagmus (recovery nystagmus), and their outcome was good. 4) On the most recent caloric test, 42% of the patients had bilateral normal responses, 27% displayed partial improvement on the affected side, and no reaction was observed in 31% of patients. We suggest that three types of clinical courses may occur in vestibular neuronitis: i) complete recovery of the function of the affected vestibular nerve, ii) partial recovery of vestibular function, and iii) no recovery of the affected vestibular nerve, but central nervous system compensates for the vestibular imbalance.

Genetic variants of ribosomal DNA and mitochondrial DNA between swamp and river buffaloes

To clarify the genetic relationship between Swamp and River buffaloes, the restriction fragment length polymorphisms (RFLPs) of nuclear genomic ribosomal DNA (rDNA) and cytoplasmic mitochondrial DNA (mtDNA) were analysed. Blood or liver samples from 73 Swamp and three River buffaloes were collected in East and South-east Asian countries. DNA samples from cattle, goats and sheep were used for comparisons. The analysis of rDNA allowed water buffaloes, cattle, goats and sheep to be characterized by four distinct repeat-types. However, swamp and river buffaloes showed the same repeat-type. Divergence of water buffalo and cattle is considered to have occurred approximately four to six million years ago. The RFLPs for mtDNA divided water buffaloes into three haplotypes, swamp-1, swamp-2 and river types. Swamp-1 accounted for 91% of all swamp buffaloes while swamp-2 was observed only in water buffaloes from Thailand (9%). All river buffaloes were of the same haplotype. No differences were observed between swamp and river buffaloes at the rDNA level. In contrast, a few distinct differences between them were found at the mtDNA level. Therefore, mtDNA polymorphisms provide an adequate means for classifying water buffaloes into either swamp or river buffaloes.

Pregnancy and delivery following cardiac operations

For young female patients with cardiac diseases, to be married, pregnancy and delivery are serious problems. Ninety-two post-operative patients (138 deliveries) and 57 non-surgical patients (86 deliveries) were subjected to analysis of their cardiac and obstetric conditions. A stable course and successful delivery were observed in the patients treated whose cardiac diseases were treated with surgical therapy. Among the non-surgical patients, however, impairment of their clinical condition was experienced including 3 maternal deaths. Incidence of various complications occurring during the course of pregnancy and delivery was 12.3% in the surgical and 18.6% in the non-surgical groups. It was clinically demonstrated that women suffering from cardiac diseases might well tolerate their pregnancy and delivery if accorded proper surgical treatment.