[Compton-scatter correction using the triple energy window (TEW) method in conventional single photon emission computed tomography without TEW acquisition hardware]

We devised a method which allowed the triple energy window (TEW) method to be applied for Compton-scatter correction in conventional single photon emission computed tomography (SPECT) systems without any hardware for TEW acquisition. In this method, the data within two subwindows located at both sides of the main window were acquired together. The effectiveness of this method was investigated by phantom experiments. The integral and differential uniformities measured using a flood phantom filled with 123I were minimized when the energy width of subwindows was 5 keV (5.8% and 4.2%, respectively). When this method was applied to a brain phantom filled with 123I in which the relative activities in white and gray matter were assigned as 1: 4.3, the ratio of SPECT values between them was more accurate (1:4.26) than that obtained without this method (1:208). This method appears to be useful for Compton-scatter correction in SPECT, because it can be applied to conventional SPECT systems without any hardware for TEW acquisition and is available for routine clinical use for its simplicity.

Relation between smoking and periodontal disease by oral hygiene status in Japanese factory workers

The relation between smoking and periodontal disease as classified by the Community Periodontal Index of Treatment Needs (CPITN) code was investigated in 1,611 Japanese male factory workers in Osaka, 20-59 years of age. The Simplified Debris Index (DI-S) according to the Simplified Oral Hygiene Index was employed as an index for the quantity of dental plaque. For the items related to smoking, a self-reporting form on smoking, the number of years of smoking, and the number of cigarettes smoked was distributed prior to the oral examination. Our results indicated the following: in the group with a poor state of oral hygiene, the negative effects of smoking were evident, resulting in unhealthy periodontal tissue. We believe that this result further confirms the contention that the removal of dental plaque is most important as a prophylaxis for periodontal diseases, and public education about this negative consequence of smoking will further strengthen prophylactic measures.

Inclusion of Volatile Organic Compounds into Natural Cyclodextrins and Their Branched Cyclodextrins in the Gaseous Phase

The adsorption isotherms of water, the differential heat of adsorption, and the entropy of adsorbed water were investigated to elucidate the structure of stability of cyclodextrins (CyD) and branched CyD's. The amount adsorbed on branched CyD's increased with increasing relative humidity. The steep rise in the amount adsorbed at higher relative humidities indicated that the structure of branched CyD's was affected by the water molecules at these higher relative humidities. The bonding force between alpha-CyD's and water molecules was stronger than that between their branched CyD's and water, while that between beta-CyD's and water was weaker than that between their branched CyD's and water. We have used activated carbons for the recovery of organic solvents. There are polar groups on the activated carbon surface. Therefore, the recovered organic solvents were degraded by these groups. However, such polar groups are not expected for the hydroxyl groups of the CyD's. The amounts of 1,1,1-trichloroethane, benzene, and toluene included in natural CyD's and their branched CyD's were measured. The amounts of organic solvents included in the CyD's depended upon the cavity radii and the glucosyl and maltosyl functional groups of the CyD's and the radii of the organic solvent molecules.

Adsorption of inhalational anesthetics and hydrochlorofluorocarbons on activated carbons as a biological model

Chlorofluorocarbon (CFC) replacements have recently been used for their lower stability and because they have carbon-hydrogen bonds, which means that their atmospheric lifetime is expected to be much shorter than those of CFCs. The adsorption properties of 1,1,2-trichloro-1,2,2-trifluoroethane (CFC113) and its replacement compounds, 1,1-dichloro-2,2,2-trifluoroethane (HCFC123), 1,1-dichloro-1-fluoroethane (HCFC141b), and 1,1-dichloro-1,2,2,3,3-pentafluoropropane (HCFC255ca) on four kinds of activated carbons were investigated. The amount of CFC and HCFCs adsorbed on the activated carbon was concluded to depend upon the number of chloride and carbon atoms in their molecules. The adsorption isotherms of inhalational anesthetics (halothane, chloroform, enflurane, isoflurane, and methoxyflurane) on the activated carbon were measured to evaluate the action mechanism of inhalational anesthesia. The adsorption isotherms of CFC, HCFC, and the inhalational anesthetics were fitted to the Freundlich equation. The Freundlich constant N was well correlated with the minimum alveolar concentration (MAC) of the inhalational anesthetic: 1 MAC means that 50% of the patients will not move during a surgical operation. The adsorption mechanism of inhalational anesthetics on the surface of the activated carbon is concluded to be similar to the adsorption mechanism on a nerve cell. The anesthesia of CFC replacements can be estimated by the Freundlich constant N of the adsorption isotherms.

Lifestyles and periodontal disease of Japanese factory workers

The association between lifestyle and periodontal disease as classified by the Community Periodontal Index of Treatment Needs (CPITN) was investigated in 1,821 factory workers, 20-69 years of age, residing in Osaka, Japan. Lifestyles were examined using a questionnaire concerning the smoking habits, alcohol consumption, physical exercise, sleeping hours and dietary habits of male factory workers.Age and sex were strongly associated with the CPITN score. In the male factory workers, the CPITN scores of each age group were significantly greater for smokers than for nonsmokers; mesn ± S.D., 2.41 ± 0.96 and 2.28 ± 0.87, respectively. The CPITN scores were also greater in high-consumption and long-duration smokers, compared to low-consumption and short-duration smokers in male factory workers.Our results show that sex, aging and smoking are risk indicators for periodontal disease.

A multicenter validation of regional cerebral blood flow quantitation using [123I]iodoamphetamine and single photon emission computed tomography

Recently, two methods have been proposed for regional cerebral blood flow (rCBF) quantitation using [123I]iodoamphetamine (IMP) and single-photon emission computed tomography (SPECT). The table look-up (TLU) method has been shown to provide both rCBF and volume of distribution, Vd, images from two SPECT scans, while a single-scan autoradiographic (ARG) technique provided rCBF using a fixed and assumed Vd. In both methods, a single blood sample was referred to calibrate the previously determined standard input function. The present multicenter project was designed to evaluate the accuracy of both methods for use as clinical investigative tools. Ten independent institutions performed [123I]IMP-SPECT studies according to both methods in 76 subjects (10 normal volunteers, 32 patients with cerebrovascular disease, and 34 patients with other diseases). Calculated rCBF values were compared with those obtained by the following reference methods available in the participating institutions; [15O] H2O positron emission tomography (PET) (five institutions), [133Xe]SPECT (four institutions), and the [123I]IMP microsphere method (three institutions). Both ARG and TLU methods provided rCBF values that were significantly correlated with those measured by the [15O] H2O PET technique (p < 0.001 for all subjects; overall regression equation, y = 15.14 + 0.54x) and those measured by the [123I]IMP-microsphere method (p < 0.001 for all subjects: y = 2.0 + 0.80x). Significant correlation (p < 0.05) was observed in 18 of 24 subjects studied with the [133Xe] SPECT reference technique (overall regression equation, y = 15.0 + 0.55x). Mean cortical gray matter rCBF in a group of normal subject was 43.9 +/- 3.3 and 43.4 +/- 2.0 ml/min/100 g for the ARG and TLU methods, respectively. Regional Vd of [123I]IMP estimated by the TLU method was 45 ml/ml +/- 20% in the normal cortical region. Close agreement between ARG and TLU rCBF values was observed (y = -3.21 + 1.07x, r = 0.97), confirming the validity of assuming a fixed Vd in the ARG method. Results of this study demonstrate that both the ARG and TLU methods accurately and reliably estimate rCBF in a variety of clinical settings.

Metastasizing uterine leiomyoma. A case with cardiac and pulmonary metastasis

A case of histologically benign cardiac and pulmonary metastases from a uterine leiomyoma in a 45-year-old woman is reported. The solitary cardiac tumor consisted of five lobules with a stalk attached to the anterior papillary muscle of the right ventricle, which occupied the right ventricular cavity and almost completely obstructed the pulmonary main trunk in the systolic cycle. Multiple small nodules were found throughout both lungs. The cardiac tumor was resected at open heart surgery and open lung biopsy of the pulmonary lesion was simultaneously performed. Both of them were histologically identical to the apparently histologically benign uterine leiomyoma which had been resected five years previously. Based on the clinical and laboratory findings, it is postulated that antegrade metastases via the venous system resulted in the cardiac metastasis from the uterine leiomyoma and the secondary pulmonary metastasis from the cardiac tumor. In contrast to the light microscopic findings, ultrastructural examination suggested the possibility of malignancy associated with the presence of immature smooth muscle cells. This is the first reported case of a so-called benign metastasizing leiomyoma occurring in the heart.

[Experimental study on effects of a high-sugar diet and physical exercise on serum phospholipids in young adults]

The life style of young adults has been receiving attention with a view to its improvement to prevent coronary heart diseases (CHD) later in life. In this study, to determining the influence of different life styles on the serum phospholipids level, we carried out experimental studies on the effects a high sugar diet and physical exercise on serum phospholipid levels. Considering the trend for young people to consume large quantities of carbonated drinks, in which most of the sugar is sucrose, we tested the effect of a high carbohydrate diet on one group of six healthy male subjects and did not find that it caused a significant increase in the serum phospholipids level. In another group of 108 healthy young female subjects, a mild exercise regimen results in a slight, but significant decrease in the serum phospholipid level (p < 0.01). The serum total cholesterol level of the group did not exhibit a significant change.

[A time-saving approach for quantifying regional cerebral blood flow and application to split-dose method with 123I-IMP SPECT using a single-head rotating gamma-camera]

We have proposed a modified early method, which can shorten the total time required for the quantitative regional cerebral blood flow (rCBF) measurement with N-isopropyl-p(-)[123I]iodoamphetamine (123I-IMP) using single-head rotating gamma-camera and the continuous arterial sampling method. Between 7 to 25 minutes after the intravenous injection of 123I-IMP, brain activity increases linearly, the SPECT data acquisition is being performed, and during which detector is rotating continuously. Then the rCBF values based on the microsphere model were calculated using the planar images obtained before and after the above acquisition and 5 min after the injection, and input counts obtained by the continuous arterial sampling. A good correlation (r = 0.951) was observed between the rCBF values obtained by this method and the traditional method, in which the SPECT data acquisition started about 30 min after injection. Applying this method to the quantitative rCBF measurements at rest and during stress with Diamox by the split dose method of 123I-IMP, we could evaluate the rCBF at rest and cerebral perfusion reserve in the same day. We conclude that this method can shorten the total time required for the standard normal microsphere method and can be applied to the split dose method, and this method provide the rCBF values not so much affected by washout of the tracer from the brain.

Evaluation of the effects of various factors on the serum alpha hydroxybutyrate dehydrogenase activity in young females

In this study, for determining the influence of different life style on the serum alpha hydroxybutyrate dehydrogenase activity (alpha HBD), we carried out surveys and laboratory studies on the relationships of the nutritional intake, physical activity, cigarette smoking and alcohol consumption of young females with their serum alpha HBD activity. There are significant positive correlation between alpha HBD and GOT, GPT, LDH, CPK, phospholipids, total cholesterol, and HDL-cholesterol, and significant negative correlation between alpha HBD/LDH and GOT, GPT, and gamma GTP. There are significant positive or negative correlation between alpha HBD and systolic pressure, diastolic pressure, cardiac index, stoke volume and total periperal resistance, and significant negative correlation between alpha HBD/LDH and vital capacity in young females. The serum alpha HBD activity levels of nonsmokers was significant higher than those of smokers (p < 0.05). There are significant positive correlations between serum alpha HBD activity and beverage consumption, and between alpha HBD/LDH and protein, calcium, vitamin A, B1, B2, C, pulses, vegetables and milk in young females. The finding shows that the group of serum alpha HBD activity level of 240 or more units exhibited higher level of rate of those who exercised sometimes+usually than the other group in young females. However, the serum alpha HBD activity level did not show significant correlation with energy expenditures per day. Exercise at 50 and 70% VO2 max may produce a significant increase in their serum alpha HBD activity. There is a possibility that serum alpha HBD activity may serve as an indicator for ones health condition. It is undeniable that observation of variation of serum alpha HBD activity is highly significant in health maintenance.

Thallium-201 myocardial tomography with intravenous infusion of adenosine triphosphate in diagnosis of coronary artery disease

OBJECTIVES

The purpose of this study was to evaluate the feasibility, safety and diagnostic accuracy of thallium-201 myocardial tomography with intravenous adenosine triphosphate (ATP) infusion in patients with suspected coronary artery disease.

BACKGROUND

Both ATP and adenosine are potent coronary vasodilators with a very short half-life. Several studies have confirmed that the diagnostic accuracy of adenosine thallium-201 scintigraphy is comparable to that with exercise. However, a high incidence of side effects, including atrioventricular (AV) block, has also been reported. Because the appropriate infusion rate for ATP has not yet been determined, this agent has not been tested in combination with myocardial scintigraphy.

METHODS

The study group included 253 consecutive patients who underwent thallium-201 myocardial tomography with ATP infusion (0.16 mg/kg body weight per min for 5 min). The occurrence of adverse effects was carefully monitored. Of the 120 patients with coronary angiography, 76 had significant coronary artery disease. Tomographic images were assessed visually and by computer-quantified polar maps, and they were compared with the results of coronary angiography.

RESULTS

Although 56% of the patients had some adverse effects, they were transient and mild. In all patients, the ATP infusion protocol could be completed, and no patient required aminophylline; AV block occurred in only 2% of the patients. The sensitivity and specificity were 88% and 80%, respectively, by visual analysis and 91% and 86%, respectively, by computer quantification.

CONCLUSIONS

Thallium tomography with ATP is feasible and has a diagnostic value similar to that with adenosine for detecting coronary artery disease. In addition, it may have fewer side effects than adenosine myocardial tomography.

Recovery period from ureteral obstructions of different duration and severity in the rat kidney

The relationship between the period for recovery from hydronephrosis and the characteristics of the obstruction still needs to be clarified. In rat kidney the left ureter was completely obstructed for 3, 7, 14 and 21 d and the renal function was measured by renal scintigraphy using 99mTC-dimercaptosuccinic acid 3, 7 and 14 d after the obstruction was removed. In addition, recovery from unilateral partial obstruction (PO) of different degrees of severity for 7 d was examined. The kidneys with very mild PO recovered within 3 d and those with a very long period of complete obstruction (CO) did not exhibit any significant recovery. However, most of the kidneys with CO of various durations and those with 7 days PO of various degrees of severity exhibited maximum recovery 7 d after the release of the obstruction. This study suggests that the period required for maximum recovery from hydronephrosis is usually constant, unless the obstruction is too mild to cause any damage or too long to permit any recovery.

A study of embolizing materials for chemo-embolization therapy of hepatocellular carcinoma: effects of particle size and dose on chitin-containing cis-diamminedichloroplatinum(II) albumin microsphere antitumor activity in VX2 hepatic tumor model rabbits

We prepared chitin-containing cis-diamminedichloroplatinum(II) (CDDP) albumin microspheres with various particle sizes, and investigated in vitro CDDP release; the antitumor effect towards VX2 tumor introduced into rabbits was then examined. It was found that the rate of release of CDDP from chitin-containing CDDP albumin microspheres in vitro was increased with reduced particle size. Administration of microspheres to VX2 tumor-bearing rabbits via the hepatic artery resulted in different profiles of plasma platinum concentration depending on the particle size, and a higher concentration of platinum was released from the beginning of administration as particle size was reduced. The platinum content in hepatic tissue following the administration of CDDP microspheres was increased as the particle size decreased, although the rate of increase was not uniform. The antitumor effect of CDDP assessed by the suppression of tumor growth tended to be higher when microspheres of smaller sizes were used. However, no significant difference was observed in tumor growth rate between rabbits injected with microspheres smaller than 20 microns and those injected with sizes between 20 and 37 microns (p > 0.05). We also examined the relationship between the CDDP dose and antitumor effect using microspheres of less than 20 microns and observed a dose-dependent antitumor effect. No significant difference was observed, however, between 2 and 4 mg eq CDDP/kg dose levels (p > 0.05). From these results, we concluded that microsphere size and CDDP dose were strongly correlated with the augmentation of antitumor effect of chitin-containing CDDP albumin microspheres used in chemo-embolization therapy via the hepatic artery.

[Assessment of myocardial viability by thallium-201 reinjection imaging with sublingual nitroglycerin]

Although thallium-201 (201Tl) reinjection imaging improves the detection of myocardial viability compared to standard 3-4-hr redistribution (RD) imaging, it still underestimates the extent of viable myocardium. We examined whether 201Tl reinjection SPECT with sublingual nitroglycerin (NTG) had a higher sensitivity for viability detection than reinjection alone. Eighty patients with coronary artery disease were studied, 38 of them with an old myocardial infarction. At the peak of exercise, 111 MBq 201Tl was injected and the initial and the delayed SPECT images were obtained. Then, all patients were divided randomly into two groups, and in each group, SPECT data were obtained again after the injection of 37 MBq 201Tl with (NTG(+) group) or without 0.6 mg of sublingual NTG (NTG(-) group). Among 50 segments showing fixed defects on the delayed image in the NTG(+) group, 21 (42%) were found to be reversible on the reinjection image, as compared to 16 of 51 (31%) in the NTG(-) group. Twenty-two of 44 (50%) segments showing incomplete RD were found to be reversible in the NTG(+) group, while 17 of 42 (41%) segments in the NTG(-) group. Moreover, the ratio of reversible segments seen in the reinjection images was significantly higher in the collateralized regions of the NTG(+) group than in those of the NTG(-) group (20/26 vs. 14/28, p < 0.05). Thus, 201Tl reinjection SPECT with sublingual NTG improves the detection of ischemic but viable myocardium as compared to SPECT with reinjection alone.

An evaluation of the accelerated expectation maximization algorithms for single-photon emission tomography image reconstruction

We previously reported that brain single-photon emission tomography (SPET) images could be improved by using an attenuation coefficient map constructed with transmission data and the iterative expectation maximization (EM) algorithm. However, the conventional EM algorithm (CEM) typically requires 30-80 iterations to provide acceptable results, limiting its clinical applicability. Several methods have been proposed to accelerate the EM algorithm. The purpose of this study was to search for a practical method for accelerating the EM algorithm. The methods investigated here include the accelerated EM algorithm (ACEM) using additive correction, ACEM using multiplicative correction, and Tanaka's filtered iterative reconstruction method (FIR). These methods were assessed by simulated SPET studies of a phantom incorporating nonuniform attenuation and by reference to clinical brain SPET data. In the simulation studies, the above methods were evaluated by using three parameters (root mean square error, log likelihood value, and contrast recovery coefficient); the results showed that FIR had an advantage over other methods in terms of all parameters. The results obtained using the clinical data demonstrated that FIR could reconstruct acceptable images in only five iterations. These results show that FIR offers significant advantages over CEM or other ACEMs, indicating that FIR can make the EM algorithm practical for clinical use in SPET.

Thallium-201/technetium-99m-phytate (colloid) subtraction imaging of hepatocellular carcinoma

This paper evaluates the clinical usefulness of 201Tl to image hepatocellular carcinoma (HCC), using 201Tl, 99mTc-phytate (colloid) and a three-headed SPECT camera.

METHODS

The tumor-to-nontumor ratios (T/N) of 201Tl for different categories of HCC were generated. Tumors were emphasized by image subtraction (201Tl-99mTc-colloid). Thirty-three lesions in 16 patients (18 studies) with HCC were evaluated. There were 19 untreated nodular, five untreated diffuse, five local recurrent and four necrotic lesions after interventional therapy.

RESULTS

The mean T/N were as follows: untreated nodular 1.54 +/- 0.31 (mean +/- s.d.), untreated diffuse 1.28 +/- 0.26, local recurrence 1.50 +/- 0.29 and necrosis 0.22 +/- 0.06. All the tumors (except necrotic areas) were enhanced by the image subtraction.

CONCLUSION

Thallium-201 is useful for liver tumor imaging but 99mTc-phytate (colloid) is essential to discriminate 201Tl tumor uptake from normal liver accumulation. Image subtraction (201Tl/99mTc-colloid) is helpful in detecting HCC.

[A case of subacute stroke with high uptake of 99mTc-HMPAO in the reperfused infarct corresponding to low perfusion area]

We reported a case of subacute stroke which showed high uptake of 99mTc-d,l-hexamethylpropyleneamine oxime (HMPAO) in the reperfused infarct corresponding to slightly decreased perfusion by 133Xe inhalation CBF measurement. In the chronic stage, both SPECT images of 99mTc-HMPAO and 133Xe showed low perfusion in the affected lesion. It was, therefore, considered that the high uptake of 99mTc-HMPAO had represented luxury perfusion. In the subacute stage of stroke, high uptake of 99mTc-HMPAO may imply luxury perfusion but not always hyperperfusion. It is suggested that the fractional fixation of 99mTc-HMPAO temporarily change in the affected lesion and it is essential to take into consideration the clinical stage for the interpretation of SPECT images.

Studies on in vitro paraquat and diquat removal by activated carbon

The adsorption characteristics of paraquat and diquat onto activated carbon in vitro were discussed for the primary treatment of acute poisoning by accidental, suicidal or homicidal ingestion of paraquat containing herbicides. Paraquat was adsorbed onto activated carbon more abundantly and more rapidly in physiological saline solution than that in artificial gastric juice and distilled water. Most suitable solvent for paraquat removal by activated carbon was physiological saline solution (0.9% sodium chloride solution). No significant correlation was observed between the ability of paraquat removal and the properties of adsorbent. Paraquat was preferentially adsorbed onto activated carbon in the mixed solution. The adsorption abilities by activated carbon (the removal ratio, the amount adsorbed and the adsorption rate) for paraquat were larger than those for diquat, and it was enhanced by added sodium chloride and added magnesium sulfate. Enhancing effect for adsorption removal was proportional to the saline concentration. As addition of salts into carbon suspension enhanced the adsorption ability, it will contribute to the effective treatment of acute poisoning.

Comparison of [11C]diprenorphine and [11C]carfentanil in vivo binding to opiate receptors in man using a dual detector system

A simple dual detector coincidence system was used to measure the binding of [11C]carfentanil and [11C]diprenorphine to opiate receptors in normal volunteers before and after the administration of naloxone. Total radioactivity without naloxone and the ratio of total/non-specific radioactivity was 2 times greater for [11C]diprenorphine than [11C]carfentanil. The dose of naloxone required to maximally block specific [11C]diprenorphine binding was 10 times that for [11C]carfentanil, indicating that [11C]diprenorphine labels opiate receptor subtypes in addition to mu opiate receptors.

Evaluation of serum lactate dehydrogenase activity for estimation of energy expenditure in human subjects

We investigated the relationship between serum lactate dehydrogenase (LDH) activity and energy expenditure in young adults, evaluating their serum LDH activities in order to develop an index of energy expenditure. The results obtained were as follows. (1) There were significant correlations between the serum LDH activity and energy expenditure/day, energy expenditure/body weight/day and daily activity index in men. (2) There were significant correlations between the serum LDH activity and energy expenditure/day and daily activity index in women. (3) A group of men who 'rarely' exercised had lower levels of serum LDH activity than those who exercised 'sometimes' or 'usually', but little difference was noted between similar groups of women.

[The evaluation of the newly produced assay kit for the cytokeratin fragment, "ball ELSA CYFRA21-1"]

We evaluated the newly produced tumor marker assay kit, "Ball ELSA CYFRA21-1", which detects cytokeratin 19 fragment in the sera of patients with malignancies, especially lung cancers. The assay procedure is simple based on the one-step radioimmunometric assay method. The measured values depend somewhat on incubation temperature and time. Reproducibility and recovery were good. The minimum measurable level was 1 ng/ml. The dilution test was satisfactory. The CYFRA21-1 levels were gradually decreased by repeated freezing and thawing and after seven such exercises its activity dropped to about 70% of that of first assay. The presence of CYFRA21-1 antigen was strongly correlated with TPA antigen and, although some discrepancies could be observed in clinical samples, CYFRA21-1 activity was completely absorbed by anti-TPA antibody-coated beads in one sample. CYFRA21-1 levels of 44 normal controls were below 1.0 ng/ml. Assuming a cut-off value of 2.0 mg/ml, 32.7% of all cases with benign disease had values greater than 2.0 ng/ml. This fell to 21.4% on exclusion of cases of interstitial pulmonary disease. Those with malignant diseases had high CYFRA21-1 levels whether associated with lung cancer or not. The most high positive ratios were observed in squamous cell lung cancer, small cell lung cancer, and uterine cervical cancer. In conclusion, CYFRA21-1 may be a good tumor marker comparable to TPA not only for lung cancer but also other malignancies as well. High false positives for lung cancer, however, were observed in other pulmonary diseases.

[In vitro adsorption of paraquat onto substituted chitosan beads]

Paraquat removal by chitosan with different substituents was investigated in vitro for evaluation of chitosan as a paraquat adsorbent in emergency treatment for acute paraquat poisoning. Chitosan CM and SU, in which the hydroxyl group at the C6 position is replaced by a carboxymethyl and sulfonic group, respectively, removed paraquat abundantly in purified water. However an inhibitory effect of sodium chloride on paraquat removal by CM and SU was recognized. On the other hand, paraquat removal by cross-linked chitosan (BCW) was accelerated in saline solutions. It was recognized that more paraquat was removed by BCW chitosan when the sodium chloride concentration was less than 1.8%. It was confirmed that some chitosan beads (CM and SU) could function as effective paraquat adsorbents through in vitro experiments.