Intensity-dependent thermoregulatory responses at the onset of dynamic exercise in mildly heated humans

To investigate quantitatively how sweating and cutaneous blood flow responses at the onset of dynamic exercise are affected by increasing exercise intensity in mildly heated humans, 18 healthy male subjects performed cycle exercise at 30, 50, and 70% of maximal O2 uptake (VO2 max) for 60 s in a warm environment. The study was conducted in a climatic chamber with a regulated ambient temperature of 35 degrees C and relative humidity of 50%. The subjects rested in the semisupine position in the chamber for 60 min, and then sweating rate (SR) and skin blood flow were measured during cycle exercise at three different intensities. Changes in the heart rate, rating of perceived exertion, and mean arterial blood pressure were proportional to increasing exercise intensity, whereas esophageal and mean skin temperatures were essentially constant throughout the experiment. The SR on the chest, forearm, and thigh, but not on the palm, increased significantly with increasing exercise intensity (P < 0.05). The mean SR of the chest, forearm, and thigh increased 0.05 mg.cm-2.min-1 with an increase in exercise intensity equivalent to 10% VO2 max. On the other hand, the cutaneous vascular conductance (CVC) on the chest, forearm, and palm decreased significantly with increasing exercise intensity (P < 0.05). The mean CVC of the chest and forearm decreased 5.5% and the CVC on the palm decreased 8.0% with an increase in exercise intensity equivalent to 10% VO2 max. In addition, the reduction in CVC was greater on the palm than on the chest and forearm at all exercise intensities (P < 0.01). We conclude that nonthermal sweating and cutaneous blood flow responses are exercise intensity dependent but directionally opposite at the onset of dynamic exercise in mildly heated humans. Furthermore, cutaneous blood flow responses to increased exercise intensity are greater in glabrous (palm) than in nonglabrous (chest and forearm) skin.

Augmenting effect of acetic acid for acidification on bactericidal activity of hypochlorite solution

AIMS

Bactericidal activity of chlorine solution is enhanced by weak acidification. We compared the effects of various acids on the bactericidal activity of hypochlorite solution to establish a method for safe and effective use of an acidic hypochlorite solution.

METHODS AND RESULTS

The bactericidal activities of acidic hypochlorite solutions that had been adjusted to pH 5.0 with hydrochloric acid, acetic acid, citric acid, lactic acid, formic acid, phosphoric acid or sulphuric acid against Bacillus subtilis spores were compared. The acidic solutions prepared with hydrochloric acid and acetic acid showed the highest bactericidal activity, and all of the spores (5 x 106 cfu ml(-1)) were killed within 10 min. On the other hand, the solutions prepared with citric acid and lactic acid showed no bactericidal activity against any bacterial strains tested in this study despite the low pH. The amount of chlorine gas produced by the preparation using acetic acid was sixfold less than that produced from the preparation using hydrochloric acid.

CONCLUSIONS

Acetic acid is the most suitable and safe acid for the preparation of an acidic hypochlorite solution.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of this study provide useful information for establishing a method for safe and effective use of an acidic hypochlorite solution.

Significantly rapid relief from steroid-resistant nephrotic syndrome by LDL apheresis compared with steroid monotherapy

Rapid amelioration of hypercholesterolemia by LDL apheresis (LDL-A) was performed for long-standing nephrotic syndrome (NS) with hyperlipidemia due to focal segmental glomerulosclerosis (FGS) and the clinical data and prognosis were compared between LDL-A-treated and nontreated groups. Seventeen steroid-resistant NS patients treated with LDL-A (LDL-A group) and 10 NS patients treated with steroids only (steroid-monotherapy (SM) group) were compared. Serum cholesterol and phospholipid levels were significantly lowered only in the LDL-A group (p < 0.01, respectively). The LDL-A group showed a significant decrease of urinary protein (UP, p < 0.01) and increase of serum albumin (p < 0.05). Average time needed to achieve a decrease of UP to less than nephrotic range (< 3.5 g/day) was significantly shorter in the LDL-A group than in the SM group (p < 0.01). Although this is not a prospective study, it is highly expected that a rapid improvement of hypercholesterolemia by LDL-A in steroid-resistant NS will provide more rapid relief from NS than steroid therapy alone.

Changes in 99mTechnegas ventilation lung scan in a newborn with absent pulmonary valve syndrome

A newborn infant with tetralogy of Fallot and absent pulmonary valve was successfully corrected in two stages. Absent pulmonary valve syndrome presenting in early infancy manifests severe respiratory symptoms that still make challenging both management and surgical treatment. This is ascribed to tracheobronchial compression by the extremely dilated pulmonary arteries, and to the resultant pulmonary obstructive lesions. We report herein the first findings of 99mTechnegas ventilation lung scanning in an infant with the syndrome to assess the pulmonary obstructive lesions.

Genetic variation in 16S-23S rDNA internal transcribed spacer regions and the possible use of this genetic variation for molecular diagnosis of Bacteroides species

The structural variation in 16S-23S rDNA internal transcribed spacer regions (ITS) among Bacteroides species was assessed by PCR amplification and sequencing analysis, and its possible use for molecular diagnosis of these species was evaluated. Ninety strains of the genus Bacteroides, including the species B. distasonis, B. eggerthii, B. fragilis, B. ovatus, B. thetaiotaomicron, B. uniformis and B. vulgatus, produced one to three ITS amplification products with sizes ranging from 615 to 810 bp. Some Bacteroides strains could be differentiated at species level on the basis of ITS amplification patterns and restriction fragment length polymorphism (RFLP) analysis using a four-nucleotide-recognizing enzyme, Msp I. The results of sequence analysis of ITS amplification products revealed genes for Ile-tRNA and Ala-tRNA in all strains tested. The nucleotide sequence, except for that in tRNA-coding regions, was highly variable and characteristic for each species, but a common sequence among B. fragilis, B. thetaiotaomicron and B. ovatus was observed. A digoxigenin-labeled oligonucleotide probe (named FOT1), which was designed from this conserved sequence, specifically hybridized to the ITS amplification products from B. fragilis, B. thetaiotaomicron and B. ovatus. These results suggest that the ITS region is a useful target for the development of rapid and accurate techniques for identification of Bacteroides species.

Acute pulmonary embolism resulting from cardiac tumors associated with tuberous sclerosis

A case report of a neonate with cardiac tumors in association with tuberous sclerosis is presented. The rare complication of pulmonary embolism and its successful treatment by anticoagulation and thrombolytic therapy is described. The treatment of these cardiac tumors is conservative, because the tumors regress spontaneously when the diagnosis is made in infancy. However, embolic event may rarely occur as a complication of cardiac tumors. If the cardiac tumors are treated conservatively, it is important to pay close attention to the occurrence of pulmonary embolism during the follow-up period.

Intraglomerular metastasis from pancreatic cancer

Few case reports have shown the presence of metastatic tumor cells in renal glomeruli. We report one case with intraglomerular metastasis proved at renal biopsy. A 60-year-old man suffered from weight loss and fever of unknown origin. Urinalysis revealed proteinuria with cellular and granular casts. Because vasculitis was suspected, renal biopsy was performed. Presence of tumor cells occupying the glomerular capillary lumina was shown by means of light microscopy and electron microscopy. Laboratory findings revealed elevated leukocyte count (28.9 x 10(3)/mm(3)), serum granulocyte colony-stimulating factor (G-CSF) (77 pg/mL), and serum CA 19-9 (21,885 U/mL). The patient soon developed disseminated intravascular coagulation and died. Autopsy findings revealed pancreatic cancer showing positive staining for G-CSF and CA 19-9. Tumor cells in the glomerular capillary lumina showed positive staining for CA 19-9 and proliferating cell nuclear antigen (PCNA). These results suggest that the pancreatic tumor cells producing G-CSF were entrapped in the glomerular capillary lumina where they proliferated. This may have been the first step in renal metastasis.

Outbreak of Chinese herb nephropathy in Japan: are there any differences from Belgium?

OBJECTIVE

The purpose of this article was to study and clarify the features of Chinese herb nephropathy (CHN) in Japan.

PATIENTS AND METHODS

The subjects consisted of patients diagnosed as having CHN in Saiseikai Nakatsu Hospital and of those reported in the literature in Japan. We investigated the clinical and histological features of CHN patients in Japan and compared them with the Belgian cases.

RESULTS

The remarkable differences were as follows: (1) high prevalence in males compared with Belgian cases, (2) Fanconi syndrome was found in most cases, (3) no patients had malignant tumors in the urinary tract. In addition, the ascribed Chinese medicines in Japan were divided into three groups: 'Tenshin-toki-shigyaku-ka-gosyuyu-syokyo-to', 'Boui-ougi-to', and others.

CONCLUSION

CHN in Japan has some characteristics distinguished from Belgian nephropathy. One hypothesis is a susceptibility to aristolochic acids (AAs), which is considered to be a causative agent, may be different among races. Another is that there could be some other toxic substances affecting the clinical findings although they are not identified at present. Further studies must be undertaken to clarify these differences.

Inhibitory effects of bitter melon (Momordica charantia Linn.) on bacterial mutagenesis and aberrant crypt focus formation in the rat colon

Antimutagenicity and chemopreventive activity of an 80%-ethanol extract of bitter melon (Momordica charantia Linn.) against the formation of azoxymethane (AOM)-induced aberrant crypt foci (ACF) was investigated. The bitter melon extract was nonmutagenic and inhibited the mutagenicity of heterocyclic amines 2-amino-3,4-dimethylimidazo[4,5-f]quinoline and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, and aflatoxin B1 in the Salmonella mutation assay. To examine the inhibitory effect of bitter melon on AOM-induced ACF formation, male F344 rats were fed various concentrations of the extract (0.1, 0.5, and 1.0 g/kg body weight) for five weeks during the initiation stage. One week after the administration of the plant extract, rats were subcutaneously given AOM at 15 mg/kg body weight once a week for two weeks. Three rats in each group were sacrificed 12 hr after the second AOM injection to analyze DNA adducts, O6-methylguanine (O6-meG) and N7-methylguanine in the liver and colon. The remaining rats were sacrificed 3 weeks after the second AOM injection to observe ACF. To examine the inhibitory effect of the extract on ACF formation in the postinitiation stage, rats were fed the extract at 0.1 and 1.0 g/kg body weight for 12 weeks starting two weeks after the second AOM injection. Treatment with bitter melon extract significantly inhibited ACF formation in the colon during the initiation stage and dose-dependently decreased the average of O6-meG DNA adduct in the colonic mucosa. During the postinitiation stage, bitter melon extract, at 1.0 g/kg body weight, significantly inhibited ACF formation in the colon, especially the formation of ACF with four or more crypts per focus. These findings suggest that bitter melon is a possible chemopreventive agent against colon carcinogenesis.

PCR-dot blot hybridization based on the neuraminidase-encoding gene is useful for detection of Bacteroides fragilis

Bacteroides fragilis is a Gram-negative obligate anaerobe frequently isolated from clinical specimens and sometimes causes severe septicemia in compromised hosts. Increasing interest has been shown in the enterotoxigenicity and drug resistance of B. fragilis in the field of medical microbiology. We previously reported rapid detection of this anaerobe by nested PCR targeting a neuraminidase-encoding gene nanH. In the present study, we synthesized a digoxigenin-labeled oligonucleotide probe, NH1, which is specific for nanH of B. fragilis, and we combined the hybridization assay using NH1 with the nanH-PCR to detect this anaerobe in a bacteremia model mice. In the specificity test, the oligonucleotide probe, NH1, hybridized only to amplification products from B. fragilis. PCR-dot blot hybridization based on nanH enabled detection of cells of B. fragilis in blood samples even when the number was as low as 2 x 10(3) colony-forming units/ml. These findings suggest that PCR-dot blot hybridization targeting nanH is a useful procedure for diagnosis of septicemia caused by B. fragilis when viable cells in blood cannot be detected by the traditional culture techniques.

Common iliac artery aneurysm due to fibromuscular dysplasia in infants

A seven-month old female with a huge aneurysm of the right common iliac artery and multiple stenoses of her bilateral renal arteries is described. At surgery, a Gore-Tex graft was interposed between the proximal common iliac artery and the external iliac artery. A histological examination of the aneurysmal wall was compatible with medial fibromuscular dysplasia (FMD). After surgery, her blood pressure was controlled in the normal range on medical treatment. This case would be the first case of a huge common iliac artery aneurysm due to FMD in infants.

C4d and C4bp deposition along the glomerular capillary walls in a patient with preeclampsia

Complement (C) 4d and cofactor C4b binding protein (C4bp) are detected in the glomerular capillary walls of a patient with preeclampsia. A 32-year-old nullipara had proteinuria of 1.2 g/d and edema at the 33rd week of pregnancy. Gradually the urinary protein excretion increased, reaching 5.1 g/d at the 37th week. The patient also showed hypertension at this stage. After normal mature delivery, the level of the urinary protein excretion remained at 3 to 4 g/d. Renal biopsy performed by means of light and electron microscopy, 15 days after delivery, showed almost normal glomeruli and modest subendothelial widening. Immunohistochemistry indicated that immunoglobulin (Ig) A, IgG, C1q, C3c, and C4c were not deposited in the glomeruli, whereas weakly positive IgM and fibrin-related antigen (FRA) were observed. Conversely, C4d, C3d, and C4bp were strongly deposited. Protein S (PS) also was observed, with a similar distribution pattern to that of C4bp. Immunoelectron microscopy showed the deposition of C4d along the capillary walls and of C4bp in the subendothelium. These findings suggest that the C4 activation process as well as the regulation process of C system and of the inflammatory coagulation axis by C4bp and PS may play an important role in the pathophysiology of preeclampsia, so-called glomerular capillary endotheliosis (GCE).

The characteristic pattern of aminoaciduria in patients with aristolochic acid-induced Fanconi syndrome: could iminoaciduria be the hallmark of this syndrome?

BACKGROUND

In Japan the patients with Chinese herbs nephropathy (CHN), aristolochic acids-(AAs) associated renal failure, often present Fanconi syndrome. The aim of this study was to investigate the pattern of aminoaciduria in patients with AAs-induced Fanconi syndrome and to clarify whether it is different from other Fanconi syndromes reported in the literature.

SUBJECTS AND METHODS

The subjects consisted of 4 patients with Fanconi syndrome due to AAs. We studied biochemical data and urinary excretion of amino acids in the 4 patients. Amino acids in their urine were analyzed by high performance liquid chromatography (HPLC).

RESULTS

Three out of 4 patients showed in common very increased excretion ofproline, hydroxyproline and citruline. Last patient showed the very increased levels of proline and valine. Regarding glycine, which is considered to belong to the same group as imino acid and to be shared with high-affinity transport system ofproline, there was not very increased excretion.

CONCLUSION

These findings suggest that AAs would predominantly affect the low-affinity transport system of proline in the brushborder membrane of proximal tubules because the low-affinity system is considered not to be shared with glycine transport.

Clinical and genetic studies of CLCN5 mutations in Japanese families with Dent's disease

BACKGROUND

Dent's disease is an X-linked renal tubular disorder that is characterized by low molecular weight proteinuria, hypercalciuria, nephrolithiasis, and renal failure. The disease is caused by inactivation of a renal chloride channel gene, CLCN5, that encodes a 746-amino acid protein with 12 to 13 transmembrane domains. The Japanese variant of Dent's disease has been observed to be less severe, and we have investigated two unrelated Japanese families for CLCN5 mutations.

METHODS

Six patients from two unrelated families were studied. Leukocyte DNA from probands was used with CLCN5-specific primers for polymerase chain reaction (PCR) amplification of the coding region and exon-intron boundaries, and the DNA sequences of the products were determined to identify abnormalities in the gene. RNA extracted from the kidney, leukocytes, or urine sediments was used to characterize further the effects of the identified mutations.

RESULTS

beta2-microglobulinuria was detected in five patients, hypercalciuria in two patients, nephrolithiasis in three patients (2 of whom were females), and one 51-year-old man had renal failure. Two novel CLCN5 mutations consisting of an a to g transition at the invariant ag acceptor splice site of intron 5 and an intragenic deletion that encompassed the region between intron 3 and intron 6 were identified. The acceptor splice site mutation led to the utilization of two alternative cryptic splice sites in exon 6 that resulted in a frameshift or skipping of the exon 6. The deletional mutation, which resulted in a loss of exons 4, 5, and 6, is predicted to lead to a loss of domains 1 through 4. Both mutations predict truncated chloride channels that are likely to result in a functional loss.

CONCLUSIONS

The observations of renal failure in one male and nephrolithiasis in two females represent important new findings in this Japanese variant of Dent's disease that is associated with CLCN5 mutations. In addition, our study is the first to demonstrate the use of urinary sediment cells and renal tissue for the detection of CLCN5 transcript abnormalities. These results help to expand the spectrum of CLCN5 mutations associated with Dent's disease.

Sinusoidal wavelength-scanning interferometric reflectometry

We propose interferometric reflectometry in which a sinusoidal wavelength-scanning tunable laser diode is used to detect positions and profiles of multiple reflecting surfaces. An objective signal extracted from an interference signal contains modulation amplitude Z and phase alpha, which are related to the positions and profiles, respectively, of multiple reflecting surfaces. By using values of the objective signal at special times, we can produce an image intensity that shows where the reflecting surfaces exist. To obtain exact values of Z or values of alpha, we estimated the objective signal by using a conjugate gradient method. Experimental results show that a resolution of two-optical-path difference (OPD) in the image intensity is approximately 60 microm, and the final OPD precisions are 2 and 8 microm for two and three reflecting surfaces, respectively, for a wavelength-scanning width of 7 nm. Profiles of the front and rear surfaces of a silica glass plate with a thickness of 20 microm have been measured with a precision of approximately 10 nm.

Transient U wave inversion during treadmill exercise testing in patients with left anterior descending coronary artery disease

The transient U wave inversion during exercise is specific for detecting left anterior descending coronary artery (LAD) disease. In a homogeneous patient group restricted to LAD disease, however, the significance of the electrocardiographic finding has not yet been clarified. Thus, clinical characteristics in patients with angiographically documented one-vessel disease of the LAD and exercise-induced U wave inversion were delineated. Symptom-limited treadmill exercise testing was performed in 60 patients (43 men, 17 women; mean age 64 +/- 8 years) with angina pectoris whose culprit lesion was located only in the LAD. U wave polarity and amplitude were determined before, during, and after exercise with the P-Q segment as the isoelectric line. Exercise-induced transient U wave inversion was defined as positive when there was a discrete negative deflection > or = 0.05 mV within the T-P segment. Of all patients, 16 (27%) had exercise-induced U wave inversion. There were no differences in age, male gender, antianginal medication use, and coronary angiographic data between the two patients groups: patients with and without U wave inversion. Heart rate and double product of heart rate and systemic systolic blood pressure at peak exercise were also similar. Prevalence of abnormal exercise-induced S-T segment shift was 94% (15 of 16 patients) and 61% (27 of 44 patients) of patients with and without U wave inversion, respectively. The difference was statistically significant (p = 0.02). Among patients with exercise-induced S-T segment shift, the proportion of patients with S-T segment elevation to all the patients was larger in patients with U wave inversion than in patients without U wave inversion [3 (20%) of 15 patients vs 0 (0%) of 27 patients, p = 0.03)]. In conclusion, the exercise-induced U wave inversion in patients with one-vessel disease of the LAD indicates the severe degree of myocardial ischemia induced in the territory perfused by the LAD. However, the electrocardiographic finding does not appear to have independent significance since it closely correlates with the presence of S-T segment shift.

Effect of beta-blocker on left ventricular function and natriuretic peptides in patients with chronic heart failure treated with angiotensin-converting enzyme inhibitor

To evaluate whether or not beta-blockers can improve the condition of patients with heart failure treated with a combination of diuretics, digitalis and angiotensin-converting enzyme inhibitor (ACEI), 52 patients with chronic heart failure who have been treated with ACEI for more than 6 months were enrolled. They were divided into 2 groups: 26 patients continued the same therapy another 6 months or more (group A), and 26 patients were given oral metoprolol for 6 months or more, in addition to the ACEI (group B). Echocardiographic parameters and atrial and brain natriuretic peptides (ANP, BNP) were measured. The left ventricular dimensions at end-diastole and end-systole were significantly decreased and fractional shortening was significantly increased in group B after 6 months' treatment with the beta-blocker, but these parameters remained unchanged in group A. Plasma levels of both ANP and BNP were significantly decreased in group B, but remained unchanged in group A. These results indicate that concomitant beta-blocker therapy can improve left ventricular function and attenuate plasma ANP and BNP levels in patients with chronic heart failure treated with ACEI.

A functional proteomics screen of proteases in colorectal carcinoma

BACKGROUND

Proteases facilitate several steps in cancer progression. To identify proteases most suitable for drug targeting, actual enzyme activity and not messenger RNA levels or immunoassay of protein is the ideal assay readout.

MATERIALS AND METHODS

An automated microtiter plate assay format was modified to allow detection of all four major classes of proteases in tissue samples. Fifteen sets of colorectal carcinoma biopsies representing primary tumor, adjacent normal colon, and liver metastases were screened for protease activity.

RESULTS

The major proteases detected were matrix metalloproteases (MMP9, MMP2, and MMP1), cathepsin B, cathepsin D, and the mast cell serine proteases, tryptase and chymase. Matrix metalloproteases were expressed at higher levels in the primary tumor than in adjacent normal tissue. The mast cell proteases, in contrast, were at very high levels in adjacent normal tissue, and not detectable in the metastases. Cathepsin B activity was significantly higher in the primary tumor, and highest in the metastases. The major proteases detected by activity assays were then localized in biopsy sections by immunohistochemistry. Mast cell proteases were abundant in adjacent normal tissue, because of infiltration of the lamina propria by mast cells. Matrix metalloproteases were localized to the tumor cells themselves; whereas, cathepsin B was predominantly expressed by macrophages at the leading edge of invading tumors. Although only low levels of urinary plasminogen activator were detected by direct enzyme assay, immunohistochemistry showed abundant protein within the tumor.

CONCLUSIONS

This analysis, surveying all major classes of proteases by assays of activity rather than immunolocalization or in situ hybridization alone, serves to identify proteases whose activity is not completely balanced by endogenous inhibitors and which may be essential for tumor progression. These proteases are logical targets for initial efforts to produce low molecular weight protease inhibitors as potential chemotherapy.

Chinese herb nephropathy in Japan presents adult-onset Fanconi syndrome: could different components of aristolochic acids cause a different type of Chinese herb nephropathy?

BACKGROUND

We encountered two cases of Chinese herb-induced Fanconi syndrome in Japan. One component of the chinese medicine was "Kan-mokutsu" (Aristolochia manshuriensis) in which aristolochic acids (AAs) were detected.

METHODS

Renal biopsy showed flattening of proximal tubular epithelial cells and paucicellular interstitial fibrosis without glomerular lesions, all of which were in accordance with Chinese herb nephropathy (CHN). To date, many cases of CHN have been reported mainly as progressive renal failure in western countries.

RESULTS

However, our cases were different from those in that they presented Fanconi syndrome. The detected AAs in our cases consisted of aristolochic acid (AA)-I, II and D. In contrast, in Belgium, the incriminated agent was Aristolochia fangchi which consisted of AA-I, B, C, and aristolactum.

CONCLUSION

These findings could indicate that different components of AAs could cause different clinical lesions, or that the amount of ingested AAs might reflect clinical pictures, that is to say, our patients took lower volume of Chinese herbs and might be in an early stage of CHN. Furthermore, it is likely that susceptibility to this substance may be different among races. CHN would include two clinical aspects: subacute renal failure and adult-onset Fanconi syndrome. It is important to bear in mind that CHN could present Fanconi syndrome.

Apical hypertrophic cardiomyopathy associated with life-threatening paroxysmal atrial flutter with a slow ventricular response: a case report

A 58-year-old male patient had apical hypertrophic cardiomyopathy (HCM) associated with a life-threatening tachycardia due to atrial flutter. Following palpitation and dyspnea for 2-3 h, he became unconscious because of circulatory catastrophe, but was fully resuscitated. An electrocardiogram recorded just before the loss of consciousness revealed atrial flutter at a rate of 260 beats/min with a 2:1 ventricular response. He was diagnosed as having apical HCM based on the echocardiographic and left ventriculographic findings. Atrial stimulation at a rate of 150 pacings/min for 1 min caused a marked drop in systemic systolic blood pressure from 170 to 120 mmHg. The patient was treated with 150 mg of cibenzoline per day to prevent supraventricular tachyarrhythmias and to improve left ventricular diastolic function. At the time of the recent follow-up at 2 and a half years, he felt quite well.

Inhibitory effects of tea extracts on the mutagenicity of 1-methyl-1, 2,3,4-tetrahydro-beta-carboline-3-carboxylic acid on treatment with nitrite in the presence of ethanol

It has been shown that the mutagenicity of 1-methyl-1,2,3, 4-tetrahydro-beta-carboline-3-carboxylic acid (MTCCA), a major mutagen precursor in soy sauce on treatment with nitrite and ethanol, was strongly decreased by the addition of hot water extracts of green, black and oolong teas in the reaction mixture when it was treated with 50mM nitrite at pH3.0, 37 degrees C for 60min in the presence of 7.5% ethanol. The mutagenicity-decreasing activity of the teas was scarcely decreased by washing the teas with chloroform and benzene and was partly decreased by butanol and ethyl acetate. Typical polyphenols such as catechins were shown to have the antimutagenicity dose dependently. The antimutagenicity and the reducing power of tea extracts gave a positive good correlation. The results suggest that the mutagenicity of MTCCA on treatment with nitrite in the presence of ethanol may be decreased by the mixed fractions of lyophilic components such as polyphenols, which have high reducing power such as catechins and the other compounds which have little reducing power including the derivatives of the catechins and so on. Although the antimutagenicity of teas and catechins was also considerably effective when they were added after the nitrosation, that of black tea and some catechins was less effective.