Erratum: Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande [Phys. Rev. Lett. 130, 031802 (2023)]

This corrects the article DOI: 10.1103/PhysRevLett.130.031802.

Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande

We report a search for cosmic-ray boosted dark matter with protons using the 0.37  megaton×years data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross section between 10^{-33}cm^{2} and 10^{-27}cm^{2} for dark matter mass from 1  MeV/c^{2} to 300  MeV/c^{2}.

URAT1-selective inhibition ameliorates insulin resistance by attenuating diet-induced hepatic steatosis and BAT whitening in mice

Background

Accumulating evidence suggests that high uric acid is strongly associated with obesity and metabolic syndrome and drives the development of non-alcoholic fatty liver disease (NAFLD) and insulin resistance. Although urate transporter-1 (URAT1), which is primarily expressed in the kidney, plays a critical role in the development of hyperuricemia, its pathophysiological implication in NAFLD and insulin resistance remains unclear.

Objectives

We hypothesizes that URAT1 plays an important role in obesity-induced metabolic disorders, and URAT1-selective inhibitor treatment ameliorates systemic insulin resistance, NAFLD and adipose tissue dysfunction using diet-induced obese mice.

Methods

Mice fed a high-fat diet (HFD) for 16 to 18 weeks or a normal-fat diet (NFD) were treated with or without a novel oral URAT1-selective inhibitor (dotinurad [50 mg/kg/day]) for another 4 weeks.

Results

Dotinurad administration significantly ameliorated HFD-induced obesity and insulin resistance. We found that URAT1 was also expressed in the liver and brown adipose tissue (BAT) other than kidney. HFD markedly induced NAFLD, which was characterized by severe hepatic steatosis, as well as the elevation of serum ALT activity and tissue inflammatory cytokine genes (Ccl2 and TNFα), all of which were attenuated by dotinurad. Likewise, HFD significantly increased URAT1 expression in BAT, resulting in the lipid accumulation (whitening of BAT) and increased production of tissue reactive oxygen species, which were reduced by dotinurad via UCP1 activation.

Conclusions

A novel URAT1-selective inhibitor, dotinurad, ameliorates insulin resistance by attenuating hepatic steatosis and promoting rebrowning of lipid-rich BAT in HFD-induced obese mice. URAT1 serves as a key regulator of the pathophysiology of metabolic syndrome, and may be a new therapeutic target for insulin-resistant individuals, particularly those with concomitant NAFLD.

Funding Acknowledgement

Type of funding sources: None.

Xanthine oxidase inhibition attenuates doxorubicin-induced cardiotoxicity in mice

Background

Accumulating evidence suggests that high serum uric acid (UA) is associated with left ventricular (LV) dysfunction. Although xanthine oxidase (XO) activation is a critical regulatory mechanism of the terminal step in ATP and purine degradation, the pathophysiological role of cardiac tissue XO in LV dysfunction remains unclear.

Objectives

We hypothesized that cardiac XO is activated in doxorubicin-induced LV dysfunction, and XO inhibitors ameliorate LV function by inhibiting cell death signals as well as by modifying cardiac purine metabolism.

Methods

Either doxorubicin (10 mg/kg) or vehicle was intraperitonially administered in a single injection to ICR mice. Mice were treated with or without oral XO inhibitors (febuxostat 3 mg/kg/day or topiroxostat 5 mg/kg/day) for 8 days starting 24 hours before doxorubicin-injection. The LV function was assessed by echocardiography at day 6 and by ex vivo heart perfusion at day 7.

Results

Cardiac tissue XO activity measured by a highly sensitive assay with liquid chromatography/mass spectrometry (n=8 each) and cardiac UA content (n=3–6) were significantly increased in doxorubicin-treated mice at day 7 and dramatically reduced by XO inhibitors. Accordingly, XO inhibitors substantially improved LV ejection fraction (n=8 each) and LV developed pressure (n=9 each) that had been impaired by doxorubicin administration. Intriguingly, the expression of GPX4, a negative regulator of ferroptosis, was decreased in doxorubicin-treated hearts but improved by XO inhibitors (n=6 each). Furthermore, metabolome analyses revealed an enhanced purine metabolism in doxorubicin-treated hearts, and XO inhibitors suppressed the serial metabolic reaction of hypoxanthine–xanthine–UA.

Conclusions

Doxorubicin administration induces cardiac tissue XO activation associated with an impaired LV function. XO inhibition attenuates the doxorubicin-induced cardiotoxicity partly through an anti-ferroptotic effect and the conservation of tissue ATP levels by modulating purine metabolism. The present study suggests that pharmacological XO inhibition represents a potential therapeutic strategy for the treatment of doxorubicin-induced cardiotoxicity.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study was supported in part by grants-in-aid for Ministry of Education Culture, Sports, Science and Technology.

High glucose-induced oxidative stress increases IL-8 production in human gingival epithelial cells

OBJECTIVE

Diabetes is often associated with increased prevalence and severity of periodontal disease. We hypothesized that gingival epithelial cells modify periodontal disease progression and predicted that hyperglycemia would activate an inflammatory response in human gingival epithelial cells (HGECs).

MATERIALS AND METHODS

We tested our hypothesis in immortalized HGECs (epi 4 cells) isolated from periodontal tissue and transfected with the simian virus 40 T antigen. The epi 4 cells were cultured in high (25 mM, HG) and normal (6 mM, NG) glucose conditions.

RESULTS

The epi 4 cells showed increased interleukin-8 (IL-8) protein secretion and mRNA expression when cultured in HG, compared with in NG. These effects were not associated with increased cell proliferation and were not observed in a hyperosmolar control group (normal glucose with 19 mM mannitol). Increased IL-8 secretion in HG was inhibited by pretreatment with an antioxidant, N-acetylcysteine, or a protein kinase C inhibitor, Ro31-8220. Hyperglycemia did not affect IL-8 secretion by gingival fibroblasts or periodontal ligament cells. In epi 4 cells, hyperglycemia also induced expression of toll-like receptor 2 (TLR2) but not TLR4.

CONCLUSION

These findings suggest a potential participation of epithelial cells in periodontal disease during diabetes by evoking an excessive host inflammatory response.

New treatment of free-radical scavenger in adrenoleukodystrophy

WHAT IS KNOWN AND OBJECTIVE

Adrenoleukodystrophy (ALD) is an X-linked disorder and characterized by the accumulation of saturated very long-chain fatty acids. Treatment is still unsatisfactory. Our objective is to report on the effect of the free-radical scavenger, edaravone, in a patient with ALD.

CASE SUMMARY

The patient was given edaravone intravenously twice. D-ROM in cerebral spinal fluid decreased dramatically, and a shortening of neuronal transmission time as estimated on somatosensory evoked potential was observed. After terminating the treatment, his symptoms progressively reappeared.

WHAT IS NEW AND CONCLUSION

This is the first report of the use of edaravone in ALD. The drug is apparently effective in improving symptoms of ALD and should be evaluated more formally.

Sudden unexpected death associated with ileocecal duplication cyst and clinical review

Duplications of the alimentary tract are very rare. A one-month-old female presented with symptoms of anorexia, vomiting and continuous watery diarrhea. The plain abdominal radiograph showed thickened intestinal wall and signs of small bowel obstruction. The fevers, vomiting, and continuous wartery diarrhea persisted despite antibiotics, and worsened. The patient failed to respond to medical managements, 27 hours after admission, the patient died due to multiple organ failures. The autopsy was performed, small bowel obstruction due to an ileocecal duplication cyst (3 × 3 cm) was recognized. The ileocecal duplication cyst was attached to the ileum which was changed edematous and necrotic. This potential diagnosis should be borne in mind for a patient who complains of abdominal symptoms with an unknown cause, and duplication cyst should be recognized as a fatal cause in infant.

Characterization of recombinant prolyl aminopeptidase from Aspergillus oryzae

AIMS

Prolyl aminopeptidase (PAP) degrades only amino-terminal proline from peptides. The food-grade fungus Aspergillus oryzae produces this enzyme only in small amounts. In this paper, we present efficient production of recombinant PAP with an overexpression system of A. oryzae and characterization of its biochemical properties.

METHODS AND RESULTS

The gene encoding PAP was overexpressed as a His-tag fusion protein under a taka-amylase gene (amyB) promoter with a limited expressing condition in A. oryzae. The PAP activity in the mycelia grown in rich medium containing glucose (repressing condition) was twice that in starch (inducing condition). The enzyme prepared as cell-free extract was partially purified through two-step column chromatography. The PAP was estimated to be a hexameric protein and exhibited salt tolerance against NaCl of up to 4 mol l(-1).

CONCLUSIONS

Aspergillus oryzae PAP was produced under the repressing condition of amyB promoter in a PAP-overexpressing strain and purified 1800-folds. Overproduction of PAP under promoter-inducing conditions led to an increase in inactive PAP, possibly because of irregular folding.

SIGNIFICANCE AND IMPACT OF THE STUDY

PAP with a high specific activity and salt tolerance may be used effectively in the manufacturing processes of fermented foods.

Colorectal resection by a minilaparotomy approach vs. conventional operation for colon cancer. Results of a prospective randomized trial

BACKGROUND/AIMS

The aim of this study was to evaluate the outcome of patients undergoing colorectal resection for colon cancer using a minilaparotomy approach or conventional surgical procedure.

METHODOLOGY

In a prospective randomized trial, twenty consecutive patients undergoing colon resection by minilaparotomy and 26 patients undergoing conventional open colorectal resection were evaluated. Immunologic, metabolic and hemodynamic studies were performed in all patients. Cell surface markers were used to characterize Th1/2 balance, using flow cytometry. Indirect calorimetry to measure energy expenditure, and pulse dye densitometry for a hemodynamic study were performed in patients until 14 POD.

RESULTS

The lengths of laparotomy incisions were 7.5+/-1.5 cm and 20.5+/-2.5 cm in the minilaparotomy and conventional group, respectively. Mean operative time, morbidity and postoperative hospital stay of the two groups was not significantly different. However, mean operative blood loss, days to p.o. liquids and walking, and amount of analgesic usage were significantly less in the minilaparotomy group. The postoperative ratio of Th1/2 in CD4+T cells was decreased in both groups, but no significant difference was seen between the groups. Significant increase of resting energy expenditure and cardiac index was seen until day 3 in the conventional group, whereas those values increased until day 1 in the minilaparotomy group.

CONCLUSIONS

Compared with conventional colorectal resection for colon cancer, colorectal resection by minilaparotomy results in a more rapid return of bowel function, less pain and host response. However, the alternations of the host response for surgical stress between the two groups are similar in the early postoperative stage (days 1-2).

Postoperative host responses in elderly patients after gastrointestinal surgery

BACKGROUND/AIMS

The age-associated dysregulation of hemodynamic, metabolic and immune responses contributes to the high incidence of complications after major abdominal surgery.

METHODOLOGY

Ninety-five patients who underwent gastric resection (n=51) and colorectal resection (n=44) were divided according to age into Groups A (n=45, less than 70 years old), B (n=30, 70-79 years) and C (n=20, over 80 years). Flow cytometric analysis of CD4+ lymphocytes for interferon (IFN)-gamma and interleukin (IL)-4 production determined the Th1/2 balance. Energy expenditure was measured by indirect calorimetry, and hemodynamics were studied using pulse dye densitometry.

RESULTS

Surgical procedures, operating time, blood loss and morbidity did not significantly differ among the three groups. The cardiac index (CI) in group A and B increased significantly over preoperative levels until POD 3, but there were no significant perioperative changes in the CI levels of group C. Resting energy expenditure levels changed similarly to those of CI. The postoperative Th1/2 ratio decreased from young to elderly to very elderly patients, although no differences were significant before surgery. The postoperative percentage of CD4+IFN-gamma +T cells (Th1) in group C decreased significantly despite of no significant changes in that of group A and B. In contrast, the ratio of CD4+IL-4+T cells (Th2) in the all groups significantly increased after surgery.

CONCLUSIONS

Host responses in elderly patients after major abdominal surgery were more hyperdynamic and hypermetabolic than those of young patients. Postoperative dysregulation of the Th1/2 balance was also associated with aging. However, host responses appear to significantly differ between elderly and very elderly patients.

Costs and benefits of laparoscopic cholecystectomy: abdominal wall lifting vs. pneumoperitoneum procedure

BACKGROUND/AIMS

Gasless laparoscopic surgery using the abdominal wall lifting (AWL) method was first developed in Japan and has been used in various surgical fields. The AWL method allows the use of conventional reusable surgical instruments. The purpose of this study was to compare the cost-effectiveness of laparoscopic cholecystectomy (LSC) using the AWL method in relation to that using pneumoperitoneum (P) method.

METHODOLOGY

Retrospective analysis of 431 LSC procedures between 1991 and 2004 was performed. The two surgical groups consisted of consecutively operated patients with a diagnosis of cholecystolithiasis or gallbladder polyps. One group consisted of 224 LSC procedures performed using the P method from 1992 to 1998 and the other group comprised 207 LSC performed using the AWL method from 1998 to 2004. All instruments used in the P method were disposable, whereas trocars, scissors, dissectors, graspers and L-hook electrodes (excluding clips) used in the AWL method were reusable. Hospital expenses, length of hospital admission and complication rates were analyzed.

RESULTS

Mean hospital cost per case for LSC using the AWL method (dollars 6743) was 7% less expensive than that using the P method (dolars 7215). Costs of operative equipment contributed to the difference (mean dollars 912 per case) in total cost. Conversion to open cholecystectomy occurred in 6 cases (2.9%) using the AWL method and 7 cases (3.1%) using the P method. There were no significant differences in length of hospital admission or complication rates between the two groups.

CONCLUSIONS

LSC using AWL method was less expensive than that using P method. This is mainly due to the use of reusable instruments in the AWL method. If LSC is performed using the AWL method instead of using disposable equipment, considerable savings can be achieved without compromising patient safety.

Postoperative metabolic and circulatory responses in patients that express SIRS after major digestive surgery

BACKGROUND/AIMS

Systemic inflammatory response syndrome (SIRS) includes a number of pathologic states because of its loose definition. This study assessed differences in metabolic and circulatory host responses in various patients with SIRS perioperatively.

METHODOLOGY

Fifty-four patients who underwent abdominal surgeries [gastric resection (n=20), colorectal resection (n=24), hepatic resection (n=8)] were divided into two groups: Group A; SIRS (+) on 1 postoperative day (POD), (n=29), B; SIRS (-) on 1 POD, (n=25). The other eight non-operated patients with SIRS caused by infection were enrolled in Group C, as common SIRS. Indirect calorimetry, body impedance measurement to assess water compartments and pulse dye-densitometry for hemodynamic examination were performed in subjects until 14 POD.

RESULTS

The ratio of energy expenditure to basal energy expenditure (%REE) was significantly increased postoperatively, and there were significant differences on %REE from 3 POD to 14 POD between groups A and B. However, %REE in group C was 162+/-23%, which was significantly increased compared with that at 1 POD of groups A (130 +/- 17%) and B (125+/-18%). Cardiac output in group A showed a significant increase until 3 POD compared with that in group B but was significantly lower than that in group C.

CONCLUSIONS

Subjects with common SIRS caused by infection were significantly more hypermetabolic than subjects with postoperative SIRS. Adequate energy intake and circulatory management should be cautiously determined according to the severity of SIRS.

Hepatic resection leads to predominance of the T helper-2 lymphocyte phenotype

Recent studies have shown that the type 1/2 T helper (Th1/2) cell balance is shifted toward a Th2-type immune response not only by malignancy but also by surgical stress. This study evaluates in immune responses to surgical stress from liver surgery in comparison with other major abdominal surgeries. PATIENTS AND METHODS:: Eighty-five patients who underwent abdominal surgeries were divided into three groups: hepatic resection (n = 17), gastric resection (n = 38), and colorectal resection (n = 30). Blood sampling was performed before surgery, and on postoperative days (POD) 2 and 14. Cell surface markers were used to characterize Th1/2 balance by flow cytometry and a ratio of the percent IFN-gamma-producing (Th1) cells to IL-4-producing (Th2) cells were expressed as the Th1/2 balance. RESULTS:: The postoperative ratio of Th1 to Th2 was decreased significantly in all subjects to 4.5 +/- 3.0 on POD 2 from 6.7 +/- 4.2. The ratio of Th1 to Th2 in patients who underwent hepatic resection markedly decreased to 2.8 +/- 1.6 on POD 2, significantly different from those in patients undergoing gastric resection or colorectal resection. However, on POD 14 there were no longer any significant differences among the three surgical groups. CONCLUSIONS:: This study shows that hepatic resection induces a more marked shift of the Th1/2 balance toward Th2 than other major abdominal surgeries.

Hepatic resection induces a shift in the Th 1/2 balance toward Th 2 and produces hypermetabolic and hyperhemodynamic states

BACKGROUND/AIMS

Recent studies have shown that the type 1/2 T-helper (Th 1/2) cell balance is shifted toward a Th 2-type immune response not only by malignancy but also by surgical stress. The present study evaluated surgical stress as a result of liver surgery in comparison with that of other major abdominal surgeries. Immune, metabolic and circulatory responses to surgery were measured for determination of surgical stress.

METHODOLOGY

Eighty-five patients who underwent abdominal surgeries were divided into three groups: hepatic resection (n=17), gastric resection (n=38), colorectal resection (n= 30). Blood sampling was performed before surgery, and on postoperative days (POD) 2 and 14. The Th 1/2 helper T cell balance was determined by flow cytometric analysis of interferon-gamma and interleukin-4 expression. Energy expenditure was measured by indirect calorimetry, and hemodynamics was studied using pulse dye densitometry until POD 14.

RESULTS

Following surgery Th 1/2 ratios decreased significantly. Additionally, the Th 1/2 balance in patients with hepatic resection on POD 2 was significantly lower than that of patients with other major surgeries. However, on POD 14 there were no significant differences among the three groups. Resting energy expenditure and cardiac index on postoperative days 1 and 3 in patients with hepatic resection increased significantly above levels in the other surgical groups. Conversely, blood volume in the hepatic resection patients was significantly lower than that of other patients until POD 3. Ten patients who developed postoperative complications had significantly lower Th 1/2 ratios and more hypermetabolism.

CONCLUSIONS

This study reveals that hepatic resection induces a more marked shift toward a Th 2 helper T cell response and significantly more hypermetabolism than other major surgeries. A distinct pattern of Th 1/2 ratio changes during the early phase of the postoperative course in hepatic resection may be related to changes in metabolism and circulation. Therefore, determination of Th 1/2 balance may be of help in evaluating different surgical procedures, and management of energy intake and circulatory management may be cautiously determined based on the shift in Th 1/2 balance.

NOx (nitrite/nitrate) in cerebral spinal fluids obtained from patients with influenza-associated encephalopathy

It has become evident that the number of patients with a new type of influenza-associated encephalopathy is increasing in Japan. Nitric oxide (NO), a simple free radical gas, elicits a wide range of physiological and pathophysiological effects. We measured the nitrite/nitrate (NO x ) levels in cerebral spinal fluid obtained from patients with influenza-associated encephalopathy in order to evaluate the correlation between the NO production and the process of influenza-associated encephalopathy. Fifteen children were enrolled, aged from 1 to 9 years. As control we used 14 cerebral spinal fluids obtained from patients with urinary tract infection, respiratory infection or mumps meningitis without any sequela. NO 3 in influenza-associated encephalopathy was significantly higher than that of control group. On the other hand NO 2 was not significantly higher than that of control group. In particular, 4 out of 5 fatal cases revealed high NO 2 or NO 3. One case having normal levels in NO 2 and NO 3 showed that NH 3 was high. These results revealed that NO plays a role in influenza-associated encephalopathy through indirect effects of NO.

Telomeric repeat sequence of Aspergillus oryzae consists of dodeca-nucleotides

Four telomeres in the chromosomes of Aspergillus oryzae NFRI1599 were cloned and sequenced. The telomeric repeat sequence of A. oryzae consisted of dodeca-nucleotides: TTAGGGTCAACA. The length of the telomeric repeat tract was 114-136 bp, which corresponds to 9-11 repeats of the dodeca-nucleotide sequence. Compared to a chromosome internal control (18S rDNA), the telomeric sequences were found to be sensitive to BAL31 exonuclease digestion, thus proving that the identified telomeric repeat sequences were located at the most terminal tract of the chromosomes. The length of the telomeric repeat tract of A. oryzae is similar to that of Aspergillus nidulans, whose repeat unit is TTAGGG, indicating that the regulatory mechanism of telomere length might be conserved among Aspergillus species.

Cytomegalovirus DNA among children attending two day-care centers in Tokyo

BACKGROUND

In the USA, a high prevalence rate of cytomegalovirus (CMV) excretion among children in day-care centres was reported. However, there is no research about the prevalence rate of CMV among children in day-care centres in Japan.

METHODS

The CMV excretion was studied in 54 children's saliva samples, collected from two different day-care centres in Tokyo. As a control, the prevalence of CMV was studied among 61 healthy children who did not attend any day-care centers. The CMV DNA in saliva were examined by polymerase chain reaction (PCR) analysis with one pair of primers for the immediate early region. The sequence of CMV genomes were examined in CMV PCR positive samples.

RESULTS

Of the 54 saliva samples, 20.6% (6/29) and 24% (6/25) were CMV PCR positive in children at A and B day-care centres, respectively. The overall positivity of CMV PCR in saliva was 22.2% (12/54). Of the 61 saliva samples as the control study, 6.5% (4/61) were CMV PCR positive. There was a difference in the positivity in each age group of day-care centres and normal control. Each sample of the same day-care center gave conclusive and identical sequence results.

CONCLUSION

We suspected that in each day-care center that there was one prevailing viral strain. We suppose that CMV infections were acquired inside the day-care centres. This is a first report which described viral transmission in day-care centres in Japan.

Visual stimulation-induced phosphorylation of neurofilament-L in the visual cortex of dark-reared rats

In dark-reared animals, visual exposure is expected to induce drastic changes in both the physiology and anatomy of the cortical neurons, including the rearrangement of their cytoskeletal structures. Phosphorylation of neurofilament-L (NF-L) is probably associated with relatively short-term structural plasticity in vivo, because the assembly and disassembly of the filaments are regulated by phosphorylation of the head domain of NF-L. Thus, by using a series of site- and phosphorylation state-specific antibodies against NF-L, we examined how visual activation induces the phosphorylation of NF-L in the rat brain. We found no specific immunoreactivity for phosphorylated NF-L in the brain of naive rats, whereas one-hour ambient light exposure after dark rearing for ten weeks from birth induced marked phosphorylation of NF-L selectively. Also, the NF-L phosphorylation was found to be localized in the primary and secondary visual cortical areas. These findings suggest that the selective phosphorylation of NF-L plays an important role in the structural plasticity related to the visual experience.

Ellagitannins and hexahydroxydiphenoyl esters as inhibitors of vertebrate squalene epoxidase

Ellagitannins isolated from various plant sources as well as newly synthesized n-alkyl (C(1)-C(18)) esters of hexahydroxydiphenyl (HHDP) dicarboxylic acid were evaluated as enzyme inhibitors of recombinant rat squalene epoxidase, a rate-limiting enzyme of cholesterol biosynthesis. Among the ellagitannins tested, pedunculagin (IC(50) = 2.0 microM) and eugeniin (IC(50) = 1.6 microM), both containing (S)-HHDP ester group(s), showed remarkable inhibition, which was more potent than those of previously reported substrate analogue inhibitors. Furthermore, ellagic acid (IC(50) = 2.0 microM), a bislactone formed by hydrolytic release of a HHDP group from ellagitannins, was also a good inhibitor of the enzyme. On the other hand, the synthetic HHDP esters with C(6) (IC(50) = 0.93 microM) and C(8) alkyl side chains (IC(50) = 0.83 microM) showed potent enzyme inhibition at the submicromolar concentration range, while esters with shorter chain lengths (C(1)-C(4)) and a C(18) ester exhibited moderate inhibition (IC(50) = 8-47 microM).

[Effect of oxygen inhalation on myocardial opacification using levovist: an animal experimental study]

OBJECTIVES

Levovist can opacify the myocardium via venous injection, and is widely used in the clinical field. However, left ventricular opacification deteriorates during oxygen inhalation using Albunex, one of the first generation of contrast agents. This study examines the effect of blood oxygen pressure on the myocardial opacification by Levovist.

METHODS

Myocardial contrast echocardiography (Toshiba Power Vision 6000) was performed using second harmonic imaging, intermittent exposure of ultrasound (every 4 cardiac beats) and acoustic power of 1.4 mechanical index. The video intensity of the ventricular septum after venous injection of Levovist (0.5 ml of 300 mg/ml) was measured under various respiratory conditions by manipulating the respirator and oxygen inhalation. Arterial blood gas was measured and correlated with the myocardial video intensity.

RESULTS

The video intensity of myocardial opacification was lower with higher oxygen pressure in the arterial blood. Visual recognition of myocardial opacification was only 14% under high oxygen pressure over 200 mmHg. Microbubbles of Levovist form from normal air, and are easily affected by the gas concentration of the surrounding blood.

CONCLUSIONS

Myocardial opacification using Levovist is deteriorated under high oxygen pressure at examination.

[Optimal setting of focus points for myocardial contrast echocardiography with intravenous Optison (FS-69): an experimental study]

OBJECTIVES

Myocardial contrast echocardiography is useful to assess myocardil perfusion, but myocardial opacification is affected by the setup of the ultrasonic equipment. The optimal setting of focus points for adequate opacification of the myocardium was examined in myocardial contrast echocardiography.

METHODS

Myocardial contrast echocardiography was performed in six dogs using triggered second harmonic technology following intravenous administration of Optison(FS-69). The short-axis view was recorded and baseline subtracted video intensity(peak intensity: PI) was calculated at three regions of the left ventricular wall, the anterior, septum, and posterior walls, to evaluate myocardial opacification. The focus point was set at near(2 cm), middle(4 cm) and far(6 cm)points. The myocardial opacification was evaluated at each focus setting. The effect of the acoustic power was also examined by changing the mechanical index to 1.6, 1.2 or 0.8.

RESULTS

Myocardial opacification was recognized at all focus points, and segments near the focus points had high PI. However, the PI of the posterior wall was lowest at near focus, whereas the PI of the anterior wall was lowest at far focus. The difference of PI between the anterior and posterior walls was significant (p < 0.05, p < 0.01, respectively) at either focus point. Adequate myocardial opacification of all segments was observed when the focus was set at the middle point. The PI of the whole left ventricle increased relative to mechanical index.

CONCLUSIONS

Setting up of focus points at the middle of the left ventricle provides more homogeneous myocardial opacification of the whole left ventricle in myocardial contrast echocardiography, and high acoustic power possibly improves myocardial opacification. Inadequate setting of focus points leads to inadequate estimation of myocardial perfusion by myocardial contrast echocardiography.

[Usefulness of intravenous myocardial contrast echocardiography in rats]

OBJECTIVES

Few intravenous myocardial contrast echocardiography trials have evaluated myocardial perfusion in small animals. The feasibility of using intravenous myocardial contrast echocardiography to assess the ischemic area in rats was investigated.

METHODS

Fourteen open chest Wister male rats were examined. Intravenous myocardial contrast echocardiography was performed by fundamental and intermittent mode using a high frequency (5-12 MHz) transducer (SONOS 5500) with injection of NC100100 (20% dilution) into the femoral vein. The mechanical index was set to 1.6. Baseline-subtracted video intensity (256 level) was measured in the anterior, posterior, septal and lateral walls of the left ventricle. The left anterior descending artery was ligated in 16 rats. The area at risk was evaluated by myocardial contrast echocardiography and compared to the area of defect by Evans Blue staining.

RESULTS

All wall segments were clearly opacified (anterior 63.8 +/- 24.7, posterior 27.0 +/- 11.0, septal 44.5 +/- 11.6, lateral 52.3 +/- 19.1), although the baseline-subtracted video intensity of the posterior wall was low. The area at risk was clearly observed, and there was a good correlation with the nonperfused area by Evans Blue staining (y = 1.13x-3.54, r = 0.98).

CONCLUSIONS

Intravenous myocardial contrast echocardiography can detect the perfusion defect even in rats using a high frequency transducer and suitable setup of equipment.

Selective electrocatalytic oxidation of N-alkyl-N-methylanilines to N-alkylformanilides using nitroxyl radical

Electrocatalytic oxidation of N-alkyl-N-methylanilines was studied using 4-benzoyloxy-2,2,6,6-tetramethyl-piperidinyl-N-oxyl as a nitroxyl radical. The reaction with N-alkyl-N-methylanilines led to direct formation of N-alkylformanilides in the presence of H2O in reaction media in adequate conversion (>75.8%), high current efficiency (>89.2%) and high selectivity (>93.8%).

Epidemiological Survey for Hemolytic Streptococci Isolated from Children in Tokyo

During the 20-year period between 1979-1998, a total of 4,176 strains of hemolytic streptococci have been isolated from 20,118 healthy primary school children and little children in Tokyo Metropolitan (Tokubetsuku, Tama and Tosho). Culture of throat swabs every November and the following February during the 20-year period were made and serological grouping and typing for isolates were done by T agglutination method. The results were as follows. 1) Serological group of hemolytic streptococci isolated from children were 3,188 strains (76.3%) for isolates of group A out of total strains of 4,176, 569 strains (13.6%) for isolates group B, 63 strains (1.5%) for isolates of group C and 356 strains (8.5%) for isolates of group G. 2) The most dominant was T12 during 1979-1998, and other relatively frequent serotypes were T28, T1, T4, T6 in that order. These ranks of and the main epidemic serotypes showed a similar trend in the 3 areas. 3) The isolation rates of group A streptococci were 15.9% in Tokubetsuku, 17.1% in Tama and 14.9% in Tosho. The average of 3 areas were 15.8%. 4) The epidemic cases seemed to be caused by group A streptococci were 20 cases, their isolated serotype were 7 cases by T28, 5 cases by T12, 4 cases by T6, 2 cases by T4, each 1 case by T1 and T25. 5) A total of 2,927 strains of group A streptococci were examined for drug sensitivity. All strains were sensitive to beta-lactam group of antibiotics (benzylpenicillin and cephaloridine). Resistant (MIC > or = 25 micrograms/ml) to TC, CP and EM etc. were 740 strains (25.3%) in this study. The incidence of resistant strains were to TC 493 strains (66.6%) out of 740 strains, 81 strains (10.9%) for TC.CP, 72 strains (9.7%) for EM and 66 strains (8.9%) for TC.CP.EM.OL.LCM. TC resistant strains have not varied much through the whole period, but CP and EM resistant strains were very variable by year. Many resistant strains to TC were T4, to EM and multiple drug resistant were T12. 6) The rates of isolates of the same type of group A streptococci in school child individual during for the tests taken twice a year were 12.3%, indicating group A streptococci, according to the duration of the carrier state, seems to be a short period.

Can three-dimensional helical CT cholangiography before laparoscopic cholecystectomy be a substitute study for endoscopic retrograde cholangiography?

The study investigated the usefulness of three-dimensional helical computed tomography (3D-CT) before laparoscopic cholecystectomy (LSC) when compared with that of endoscopic retrograde cholangiography (ERC). Forty-five patients referred for LSC, who had undergone 3D-CT cholangiography and ERC simultaneously, participated in the study. Endoscopic retrograde cholangiography and 3D-CT cholangiography were compared in each patient with regard to opacification of the biliary tree, stones, and anatomic variations. Three-dimensional helical CT cholangiography and ERC imaging for predicting operative difficulties in LSC also were compared. The common bile duct and cystic duct were shown in the patients by the images, but the gallbladder was shown in 43 patients (96%) with use of 3D-CT cholangiography and in 36 patients (80%) with use of ERC. A third or more peripheral branches were shown completely with use of 3D-CT cholangiography in 33 patients (73%) and in 32 patients (71%) with use of ERC. Cystic duct stones were found in two of three patients with use of 3D-CT cholangiography and ERC. Common bile duct stones in five of seven patients were detected with use of 3D-CT cholangiography, but all of the common bile duct stones were detected with use of ERC. Anatomic variations of the bile duct were shown in three of four patients by 3D-CT cholangiography and in all patients with use of ERC. No significant differences in findings of the angle of bifurcation and presence of Heister valves between operative easy and complex cases were shown by 3D-CT cholangiography and ERC, despite the more accurate assessment of the cystic duct anatomy with use of 3D-CT cholangiography than with use of ERC. Three-dimensional helical CT cholangiography is useful clinically in preoperative assessment of biliary anatomy, but it is not reliable in the detection of common bile duct stones, and it is not helpful in predicting technical difficulty during LSC.

Behçet's disease associated with complement component 9 (C9) deficiency

Abstract Behçet's disease is a multisystem inflammatory disorder with unknown etiology. It has been shown that the titer of plasma complement component 9 (C9) is a good indicator of the disease activity. Therefore, the involvement of C9 in the pathogenesis of Behçet's disease has been suggested. We report a case of Behçet's disease associated with complete C9 deficiency (C9D) carrying the homozygous nonsense mutation at Arg-95 of C9 (R95X). The patient presented the typical characteristics of Behçet's disease, such as uveitis, recurrent oral aphthae and genital ulcers, and arthritis, suggesting that C9 does not play an essential role in the pathogenesis of Behçet's disease.

Inhibition of vertebrate squalene epoxidase by isoprenyl gallates and phenylalkyl gallates

Galloy esters with 'substrate-like' isoprenoid or phenylalkyl side chains were newly synthesized and tested for the enzyme inhibition activities toward recombinant rat squalene epoxidase. Isoprenyl gallates (4-6) showed good inhibition (IC50 = 1.5 5.1 microM), as potent as previously reported substrate analogues, while phenylalkyl gallates (7-10) were moderate inhibitors of the enzyme (IC50 = 12-61 microM).

[Study on casein allergy in children]

Casein a component of milk is used for food additives, industrial materials and drugs. However casein is known to be a main allergen in milk allergy. Recently several cases of anaphylaxis to antibiotics including casein have been reported. In this study we investigated casein allergy in milk allergy. 6 out of 8 patients who were positive for milk RAST were also positive for casein RAST. In these positive cases only 3 out of 6 patients had some allergic symptoms after taking antibiotics. In 3 patients DLST was also positive to casein. There was one patient who was positive in DLST without any symptoms after taking the same antibiotics. It is needed to pay attention to casein allergy when giving the medication which includes casein.

Loss of diurnal variation in ornithine decarboxylase and apoptosis in small intestine of Mongolian gerbils

The aim of this study was to examine the diurnal variations in ornithine decarboxylase (ODC) activity and apoptosis in the small intestinal mucosa of Mongolian gerbils. First, the feeding, drinking, and ambulatory patterns of the gerbils were recorded. The results indicated that Mongolian gerbils lost diurnal cyclicity in feeding, drinking, and ambulatory patterns. Second, ODC activity and apoptosis in the intestinal mucosa of gerbils were characterized by measurements at four time points (11:00, 17:00, 23:00, and 05:00 h; light period, 08:00-20:00 h). Apoptosis was evaluated in terms of percent fragmented DNA (fragmented DNA/total DNA). Neither ODC activity nor apoptosis showed diurnal variation in the jejunal mucosa of the Mongolian gerbils. In 48-h fasted gerbils, ODC activity in the intestinal mucosa decreased, but this activity increased significantly 2 h after refeeding; percent fragmented DNA increased in the intestinal mucosa, and returned to the control level 2 h after refeeding. These results indicate that postprandial local nutrients are an important factor in regulating diurnal variation in ODC activity and apoptosis in the small intestine of gerbils.

Single genotype of measles virus is dominant whereas several genotypes of mumps virus are co-circulating

We have reported that in Japan measles virus strains have been classified into three distinct different genotypes (C1, D3 and D5) under the new international genotype classification since 1984. Similarly, mumps virus strains have been divided into two genotypes with three subtypes (B1, B2, B3, and D) under the proposed international classification since 1976. To differentiate these genotypes we developed a restriction fragment length polymorphism assay in the hemagglutinin (H) region for measles virus and in the hemagglutinin-neuraminidase (HN) region for mumps virus to facilitate the expanded molecular epidemiology. In the Sapporo 1995/1996 measles outbreak, all 26 strains were classified as D5. Among 32 samples from patients with measles from 1994 to 1997 in Tokyo, 28 were identified as D5 and four were D3; these D3 strains were ascertained as a same hospital acquired infection. Among 45 strains obtained in the Tokyo 1999 outbreak, 38 were D3 and the remaining seven were D5. The dominant genotype of measles in Tokyo has replaced from D5 to D3 similar to the Chicago1/89 strain. We obtained 220 samples from patients with mumps from 1993 to 1997 and they were classified into one strain of B1, 14 strains of B2, 151 strains of B3, and 54 strains of D. Therefore, we suggest that two or three subtypes of mumps virus are co-circulating with a different geographic pattern in genotype distribution, whereas a single measles virus genotype is dominantly observed, showing different epidemiological patterns.

Localized phosphorylation of vimentin by rho-kinase in neuroblastoma N2a cells

BACKGROUND

Vimentin, which is one of the intermediate filaments, is the major cytoskeletal component in developing neurones or neuroblastoma cells. Rho-associated kinase (Rho-kinase), is rich in neurones and is found downstream of Rho. It is involved in the agonist-induced neurite retraction of neuronal cells, and phosphorylates vimentin at Ser-38 and Ser-71 resulting in in vitro disassembly of the filaments.

RESULTS

We have investigated the distribution of vimentin phosphorylated by Rho-kinase in N2a neuroblastoma cells using site-specific phosphorylation-dependent antibodies. TM71 immunoreactivity, which specifically indicates Ser-71 phosphorylation on vimentin, was found in some neurites of dibutyryl cAMP-differentiated N2a cells. Transfection of the constitutively active form of Rho-kinase, CAT, significantly elevated TM71 immunoreactivity, and induced neurite retraction or cell rounding. Conversely, transfection of the dominant negative form of Rho-kinase, RB/PH(TT), or treatment of 10 microM Y-27632, a Rho-kinase specific inhibitor, abolished TM71 immuno-reactivity, and induced irregular neurite outgrowth. In contrast, 20 nM okadaic acid (OA) induced neurite retraction and specifically elevated TM71 immunoreactivity. In the OA-induced neurite retraction, tubulin disappeared in retracting neurites, where vimentin and actin remained co-localized. Furthermore, the OA-induced elevation of TM71 immunoreactivity and neurite retraction were completely blocked by pretreatment with 10 microM Y-27632, or by the ectopic expression of RB/PH(TT).

CONCLUSIONS

This study suggests that the localized phosphorylation of vimentin by Rho-kinase in neurites was closely related with the cellular morphology of N2a cells, and that the Rho-kinase activity towards vimentin was balanced with OA-sensitive phosphatases.

Phosphorylation of neurofilament-L during LTD

We recently reported that CaMKII-dependent phosphorylation of the neurofilament-L (NF-L) head domain was induced in the apical dendrites during long-term potentiation. Long-term depression (LTD) is another cellular model for neuronal plasticity. In the present study, we examined the phosphorylation of NF-L during hippocampal LTD using a series of phospho-specific antibodies against the NF-L head domain. During LTD, these antibodies visualized NF-L phosphorylation at Ser57 in the apical dendrites of the hippocampal pyramidal neurons. The assembly and disassembly of NF-L filaments are regulated by phosphorylation of its head domain. Thus, our results indicated that NF-L phosphorylation might be associated with alterations of the neuronal structure during LTD.

[Cytomegalovirus (CMV) infection in infants may result intractable stridor]

We found ten cases of human cytomegalovirus (CMV) infection who were intractable stridor. Their symptoms were not improved by the treatment with aminophyllin nor beta stimulants. They were admitted repeatedly complaining of stridor, fever and diarrhea. In two cases, the immunological findings showed a decrease of bacterial sterilizing activity of the neutrophils. Additionally, blood count showed leukocytosis more than 15,000/ul in all cases. Total serum IgE and specific IgE antibodies to many antigens were not elevated. Transaminase was elevated. Chest X-p findings of interstitial pneumonia or atelectasis continued for a long time in some cases. Virological examinations revealed high concentrations of specific IgM or CF antibodies against CMV in all cases. CMV DNA in saliva were examined by polymerase chain reaction (PCR) with primer sets for the immediate early (IE) region of CMV and showed positive in seven cases. CMV in bronchoalveolar lavage (BAL) was isolated in two cases, and CMV PCR in BAL was positive in three cases. The sequence of the CMV-PCR products showed almost same sequence except one point mutation in bp 1203. We considered that CMV infections in infants may induce stridor for a long period.

Site-specific phosphorylation of neurofilament-L is mediated by calcium/calmodulin-dependent protein kinase II in the apical dendrites during long-term potentiation

Neurofilament-L (NF-L), one subunit of the neuronal intermediate filaments, is a major element of neuronal cytoskeletons. The dynamics of NF-L are regulated by phosphorylation of its head domain. The phosphorylation sites of the NF-L head domain by protein kinase A, protein kinase C, and Rho-associated kinase have been previously identified, and those by calcium/calmodulin-dependent protein kinase II (CaMKII) were identified in this study. A series of site- and phosphorylation state-specific antibodies against NF-L was prepared to investigate NF-L phosphorylation in neuronal systems. Long-term potentiation (LTP) is a cellular model of neuronal plasticity that is thought to involve the phosphorylation of various proteins. NF-L is considered a possible substrate for phosphorylation. During LTP stimulation of mouse hippocampal slices, the series of antibodies demonstrated the increase in the phosphorylation level of Ser(57) in NF-L and the visualization of the localized distribution of Ser(57) phosphorylation in a subpopulation of apical dendrites of the pyramidal neurons. Furthermore, Ser(57) phosphorylation during LTP is suggested to be mediated by CaMKII. Here we show that NF-L is phosphorylated by CaMKII in a subpopulation of apical dendrites during LTP, indicating that Ser(57) is a novel phosphorylation site of NF-L in vivo related to the neuronal signal transduction.

Detection and sequencing of measles virus from peripheral mononuclear cells from patients with inflammatory bowel disease and autism

It has been reported that measles virus may be present in the intestine of patients with Crohn's disease. Additionally, a new syndrome has been reported in children with autism who exhibited developmental regression and gastrointestinal symptoms (autistic enterocolitis), in some cases soon after MMR vaccine. It is not known whether the virus, if confirmed to be present in these patients, derives from either wild strains or vaccine strains. In order to characterize the strains that may be present, we have carried out the detection of measles genomic RNA in peripheral mononuclear cells (PBMC) in eight patients with Crohn's disease, three patients with ulcerative colitis, and nine children with autistic enterocolitis. As controls, we examined healthy children and patients with SSPE, SLE, HIV-1 (a total of eight cases). RNA was purified from PBMC by Ficoll-paque, followed by reverse transcription using AMV; cDNAs were subjected to nested PCR for detection of specific regions of the hemagglutinin (H) and fusion (F) gene regions. Positive samples were sequenced directly, in nucleotides 8393-8676 (H region) or 5325-5465 (from noncoding F to coding F region). One of eight patients with Crohn disease, one of three patients with ulcerative colitis, and three of nine children with autism, were positive. Controls were all negative. The sequences obtained from the patients with Crohn's disease shared the characteristics with wild-strain virus. The sequences obtained from the patients with ulcerative colitis and children with autism were consistent with being vaccine strains. The results were concordant with the exposure history of the patients. Persistence of measles virus was confirmed in PBMC in some patients with chronic intestinal inflammation.

Major phosphorylation site (Ser55) of neurofilament L by cyclic AMP-dependent protein kinase in rat primary neuronal culture

Ser55 of neurofilament L (NF-L) is reported to be partly phosphorylated in neurons and to be phosphorylated by cyclic AMP-dependent protein kinase (PKA). Bovine NF-L was phosphorylated by PKA in a low concentration of MgCl2 (0.3 mM) and digested by trypsin. Trypsin-digested fragments were assigned by MALDI/ TOF (matrix-assisted laser desorption and ionization/ time-of-flight) mass spectrometry. Phosphorylation sites were found at Ser41, Ser55, and Ser62 in the head region, with Ser55 considered the preferred site. A site-specific phosphorylation-dependent antibody against Ser55 rendered NF-L phosphorylated at Ser55 detectable in primary cultured rat neurons. One-hour treatment with 20 nM okadaic acid increased the phosphorylation level of Ser55, and co-treatment with 10 microM forskolin enhanced it. However, forskolin alone did not elevate the phosphorylation level. As a consequence, NF-L may be phosphorylated at Ser55 by PKA or by a PKA-like kinase in vivo; however, the phosphorylation level of Ser55 may be modulated by certain phosphatases sensitive to okadaic acid.

Are cerebrovascular factors involved in Alzheimer's disease?

Recent epidemiological studies have shown that vascular risk factors may be involved in Alzheimer's disease (AD) as well as dementia in general. To investigate the relation between a vascular disorder and AD pathology, current criteria are defective because most depend on exclusion of a cerebrovascular disorder. Epidemiological studies have indicated the possibilities that arteriosclerosis, abnormal blood pressure, diabetes mellitus and smoking may be related to the pathogenesis of AD. As for the mechanism that vascular disorders influence AD, it is presumed that amyloid deposition may be caused by a vascular disorder. Alternatively, a vascular event may cause progression of subclinical AD to a clinical stage. Insulin resistance and apolipoprotein E may also be involved in these mechanisms. Our studies show that ischemia-induced the Alzheimer-associated gene presenilin 1 (PS1) and endoplasmic reticulum-stress, generated from a vascular disorder, may unmask clinical AD symptoms caused by presenilin mutation, suggesting that a vascular factor might be involved in the onset of familial AD.

Lethal effect of the expression of a killer gene SMK1 in Saccharomyces cerevisiae

Expression of the SMK1 gene which encodes the yeast killer toxin SMKT is lethal in Saccharomyces cerevisiae. Effects of deletion and site-directed mutagenesis of SMK1 on the lethality and the secretion of the gene products were examined. Deletion of the interstitial gamma peptide or the C-terminal loop from Ala208 to the C-terminal Asp222 had no effect on the lethality. Those SMK1 products that lacked either the gamma peptide or the C-terminal loop were expressed in the cells but were not secreted into the culture medium, suggesting that these peptides may have a role in secretion or in protein stability. On the other hand, deletion of the signal sequence resulted in complete loss of the lethal activity. Entering the secretory pathway may be critical for the lethality. Further, deletion of the region from the C-terminus to Leu207 resulted in loss of the lethal activity. Leu207 is located at the C-terminus of the central strand of the beta-sheet structure of SMKT and its side chain is thrust into a hydrophobic environment between the beta-sheet and the alpha-helices. The result obtained upon substitutions of Ala, Ser or Glu for Leu207 suggested that the side chain of Leu207 stabilizes the hydrophobic environment that contributes to the overall structure of the SMK1 product.

[Understanding of molecular pathogenesis of Alzheimer's disease: implications for drug development]

Recent advances in the knowledge about Alzheimer pathogenesis indicate several tactics for the development of drugs to treat Alzheimer's disease. Firstly, the function of presenilin, the causative gene for most familial Alzheimer's disease, has been demonstrated to be the protease in the Notch signaling system. Presenilin cleaves the transmembrane domain of the C-terminal fragment of the Notch-1 molecule, which is generated by proteolysis by furin-like proteases. APP is also cleaved by presenilin at the gamma cut site, implying that presenilin is gamma-secretase itself or at least closely functioning with gamma-secretase. A recent paper has demonstrated that immunization of APP transgenic mouse with amyloid beta 42 may decrease and prevent amyloid deposition in brain tissue. This unique and novel approach may open the new tactics for developing anti-dementia drugs. Another important finding comes from the identification of the function of prolyl isomerase. It is demonstrated that pin 1, intra-nuclear prolyl isomerase, can restore the microtubule binding capacity of phosphorylated tau, which clearly shows a solid strategy for developing drugs for preventing neuronal degeneration.

An electrospray-ionization mass spectrometry analysis of the pH-dependent dissociation and denaturation processes of a heterodimeric protein

Electrospray ionization mass spectrometry (ESI-MS) was applied to the analysis of the dissociation and denaturation processes of a heterodimeric yeast killer toxin SMKT. The two distinct subunits of SMKT noncovalently associate under acidic conditions, but become dissociated and denatured under neutral and basic conditions. In order to understand the unique pH-dependent denaturation mechanism of this protein, a pH titration was performed by utilizing ESI-MS. The molecular ions of the heterodimer which possesses the highly ordered structure, were mainly observed below pH 4.6. However, the two subunits immediately dissociated at this pH. The spectra measured with various settings of the mass spectrometer indirectly demonstrated that the pH-dependent dissociation occurs in the liquid phase. The current result as well as the three-dimensional structure of SMKT suggest that the deprotonation of a specific carboxyl group triggers a cooperative dissociation process of this protein. In conclusion, the pH titration of a protein by ESI-MS is particularly effective, when the unfolding process or the biological function of the protein is related to the interaction with other molecules.

Radical intensity and cytotoxicity of butylated hydroxyanisole and its orthobisphenol dimer

The radical intensity of BHA (4-Hydroxy-3-t-butylanisole) and its dimer (3,3'-Di-t-butyl-5,5'-dimethoxy-1,1'-biphenyl-2,2'-diol, Bis-BHA) were compared with their cytotoxic activity. ESR spectroscopy showed that BHA produced characteristic five peaks of radicals under alkaline conditions (pH > 9.5). At higher pH, BHA radical rapidly disappeared, and progressively transformed into new radical species, as detected by the splitting of the ESR signal. BHA showed higher cytotoxic activity against salivary gland tumor cell line than against normal human gingival fibroblast. On the other hand, Bis-BHA did not produce any detectable amounts of radicals at wide ranges of pH, corresponding with its weaker cytotoxic activity as compared with BHA. BHA scavenged DPPH (1,1-Diphenyl-2-picrylhydrazyl) radical and superoxide anion, more efficiently than Bis-BHA. The present study demonstrated that BHA is more cytotoxic, produces higher amounts of radicals and more efficiently scavenges various radical species, as compared with Bis-BHA. This suggests the possible link between the cytotoxic activity and radical generation/scavenging activity in BHA-derived compounds.