[Frequency and severity of sarcopenia in patients with inflammatory and noninflammatory musculoskeletal diseases : Results of a monocentric study in a tertiary care center]. / Häufigkeit und Schweregrad von Sarkopenie bei Patient*innen mit entzündlichen und nichtentzündlichen muskuloskeletalen Erkrankungen : Ergebnisse einer monozentrischen Studie in einem tertiären Zentrum.

INTRODUCTION: Sarcopenia (SP) is defined as the pathological loss of muscle mass and function. This is a clinically relevant problem, especially in geriatric patients, because SP is associated with falls, frailty, loss of function, and increased mortality. People with inflammatory and degenerative rheumatic musculoskeletal disorders (RMD) are also at risk for developing SP; however, there is little research on the prevalence of this health disorder in this patient group using currently available SP criteria. OBJECTIVE: To investigate the prevalence and severity of SP in patients with RMD. METHODS: A total of 141 consecutive patients over 65 years of age with rheumatoid arthritis (RA), spondylarthritis (SpA), vasculitis, and noninflammatory musculoskeletal diseases were recruited in a cross-sectional study at a tertiary care center. The European Working Group on Sarcopenia in Older People (EWGSOP 1 and 2) definitions of presarcopenia, SP, and severe SP were used to determine the prevalence. Lean mass as a parameter of muscle mass and bone density were measured by dual X­ray absorptiometry (DXA). Handgrip strength and the short physical performance battery (SPPB) were performed in a standardized manner. Furthermore, the frequency of falls and the presence of frailty were determined. Student's T-test and the χ2-test were used for statistics. RESULTS: Of the patients included 73% were female, the mean age was 73 years and 80% had an inflammatory RMD. According to EWGSOP 2, 58.9% of participants probable had SP due to low muscle function. When muscle mass was added for confirmation, the prevalence of SP was 10.6%, 5.6% of whom had severe SP. The prevalence was numerically but not statistically different between inflammatory (11.5%) and noninflammatory RMD (7.1%). The prevalence of SP was highest in patients with RA (9.5%) and vasculitis (24%), and lowest in SpA (4%). Both osteoporosis (40% vs. 18.5%) and falls (15% vs. 8.6%) occurred more frequently in patients with SP than those without SP. DISCUSSION: This study showed a relatively high prevalence of SP, especially in patients with RA and vasculitis. In patients at risk, measures to detect SP should routinely be performed in a standardized manner in the clinical practice. The high frequency of muscle function deficits in this study population supports the importance of measuring muscle mass in addition to bone density with DXA to confirm SP.

The Refeeding Syndrome revisited: you can only diagnose what you know.

BACKGROUND/OBJECTIVES: The Refeeding Syndrome (RFS) is a serious complication in patients receiving nutrition support after a period of severe malnutrition. We frequently recognize and diagnose the RFS due to increased awareness. Thus, we observe that many physicians do not know the RFS and that it is rarely diagnosed. The aim of the study was to determine whether physicians in Germany know the RFS. SUBJECTS/METHODS: A questionnaire with a case vignette about an older person who developed the RFS after initiation of nutritional therapy was submitted to German physicians and fifth year medical students, who were participants of educational lectures. RESULTS: Of the 281 participants who answered the respective question, 40 participants (14%) correctly diagnosed the RFS of the case vignette and 21 participants (8%) gave nearly correct answers. Indeed, the majority of the participants did not diagnose the RFS. CONCLUSIONS: Although the RFS may lead to fatal complications, it is unknown to the majority of the queried physicians. Therefore, there is a call to implement the RFS in respective curricula and increase systematic education on this topic.

Seasonal Variation in Vitamin D Status among Frail Older Hospitalized Patients.

BACKGROUND AND OBJECTIVES: Seasonal variation in 25-hydroxyvitamin D [25(OH)D] levels is the result of sunlight dependent skin synthesis of vitamin D. However, its presence is not studied in frail older hospitalized patients. We sought to investigate whether seasonal variation in 25(OH)D levels is evident among these patients. DESIGN AND SETTING: This study investigated older participants who were consecutively admitted between February 2015 and December 2016 to the geriatric acute care ward. Results of routine measurements of 25(OH)D at hospital admission were retrospectively analyzed and stratified according to months and seasons. Previous intake of vitamin D supplementation was derived from the patients' medical records. RESULTS: The study group comprised 679 participants (mean age 82.1±8.2; 457 females), of which 78% had vitamin D deficiency. Older individuals not taking vitamin D supplements had a lower mean serum 25(OH)D than those receiving supplements. Of those patients with no vitamin D supplementation, 87.0% were vitamin D deficient and only 5% showing sufficient vitamin 25(OH)D. Further, there were neither monthly nor seasonal variations in vitamin 25(OH)D levels among these patients and their vitamin D levels stayed far below the recommended threshold of 20 ng/ml across the seasons. CONCLUSION: Vitamin D deficiency was very prevalent in the subgroup of older hospitalized patients without vitamin D supplementation, irrespective of season. Since no seasonal variations in mean 25(OH)D levels was observed, sunlight dependent skin synthesis is unlikely to contribute to vitamin D status in these patients. Supplementation seems to be necessary to maintain desirable vitamin D levels among this population throughout the year.

The Association of Inflammation with Food Intake in Older Hospitalized Patients.

OBJECTIVES: An acute inflammatory process may play a role in inhibiting appetite and food intake particularly in acutely ill older individuals. However, there is a lack of knowledge on the effect of inflammation on food intake in humans. In this study, we sought to investigate the association of C-reactive protein (CRP), as an inflammatory marker, with food intake in acutely ill older hospitalized patients. DESIGN AND SETTING: This cross-sectional study investigated older participants who were consecutively admitted to a geriatric acute care ward. Food intake during previous week was measured according to the Nutritional Risk Screening (NRS-2002) and patients were grouped into two categories as intake ≥75% and <75% of requirements. Disease severity and mobility were measured based on the NRS-2002 and Mini Nutritional Assessment Short Form (MNA-SF), respectively. Serum CRP was analyzed according to standard procedures. RESULTS: Of 177 older participants (mean age 83.1 ± 6.5 y, BMI range of 14.7-43.6 kg/m2; 116 females), 67 (38.0%) had moderate to severe inflammation (CRP>3.0 mg/dl). In addition, 109 (62.0%) patients had intake <75% of requirements during previous week, in which 34 (31.0%) and 54 (50.0%) demonstrated mild and moderate to severe inflammation, respectively. Furthermore, there were significant differences in CRP levels between intake ≥75% and <75% of requirements (P<0.001). In a logistic regression analysis, CRP level (odds ratio; OR, 1.14; P=0.006), disease severity (OR, 2.94; P=0.022), mobility (OR, 0.44; P=0.005) and BMI (OR, 0.89; P=0.003) were the major independent predictors of low food intake. CONCLUSION: Our findings confirm a close association between food intake and inflammation in older hospitalized patients. In addition, CRP level and disease severity together were the most important independent predictors associated with food intake in these patients.

[Refeeding syndrome : Pathophysiology, risk factors, prevention, and treatment]. / Refeeding-Syndrom : Pathophysiologie, Risikofaktoren, Prophylaxe und Therapie.

Refeeding syndrome is a life-threatening complication that may occur after initiation of nutritional therapy in malnourished patients, as well as after periods of fasting and hunger. Refeeding syndrome can be effectively prevented and treated if its risk factors and pathophysiology are known. The initial measurement of thiamine level and serum electrolytes, including phosphate and magnesium, their supplementation if necessary, and a slow increase in nutritional intake along with close monitoring of serum electrolytes play an important role. Since refeeding syndrome is not well known and the symptoms can be extremely heterogeneous, this complication is poorly recognized, especially against the background of severe disease and multimorbidity. This overview aims to summarize the current knowledge and increase awareness about refeeding syndrome.

Impact of Sarcopenia on One-Year Mortality among Older Hospitalized Patients with Impaired Mobility.

OBJECTIVES: However, the information regarding the impact of sarcopenia on mortality in older individuals is rising, there is a lack of knowledge concerning this issue among geriatric hospitalized patients. Therefore, aim of the present study was to investigate the associations between sarcopenia and 1-year mortality in a prospectively recruited sample of geriatric inpatients with different mobility and dependency status. DESIGN AND SETTING: Sarcopenia was diagnosed using the criteria of the European Working Group on Sarcopenia in Older People (EWGSOP). Hand grip strength and skeletal muscle mass were measured using Jamar dynamometer and bioelectrical impedance analysis, respectively. Physical function was assessed with the Short Physical Performance Battery. Dependency status was defined by Barthel-Index (BI). Mobility limitation was defined according to walking ability as described in BI. The survival status was ascertained by telephone interview. RESULTS: The recruited population comprised 198 patients from a geriatric acute ward with a mean age of 82.8 ± 5.9 (70.2% females). 50 (25.3%) patients had sarcopenia, while 148 (74.7%) had no sarcopenia. 14 (28%) patients died among sarcopenic subjects compared with 28 (19%) non-sarcopenic subjects (P=0.229). After adjustment for potential confounders, sarcopenia was associated with increased mortality among patients with limited mobility prior to admission (n=138, hazard ratio, HR: 2.52, 95% CI: 1.17-5.44) and at time of discharge (n=162, HR: 1.93, 95% CI: 0.67-3.22). In a sub-group of patients with pre-admission BI<60 (n=45), <70 (n=73) and <80 (n=108), the risk of death was 3.63, 2.80 and 2.55 times higher in sarcopenic patients, respectively. In contrast, no significant relationships were observed between sarcopenia and mortality across the different scores of BI during admission and at time of discharge. CONCLUSION: Sarcopenia is significantly associated with higher risk of mortality among sub-groups of older patients with limited mobility and impaired functional status, independently of age and other clinical variables.

Prevalence of Risk Factors for the Refeeding Syndrome in Older Hospitalized Patients.

OBJECTIVES: The incidence of refeeding syndrome (RFS) in older patients is not well-known. The aim of the study was to determine the prevalence of known risk factors for RFS in older individuals during hospitalization at geriatric hospital departments. DESIGN AND SETTING: 342 consecutive older participants (222 females) who admitted at acute geriatric hospital wards were included in a cross-sectional study. We applied the National Institute for Health and Clinical Excellence (NICE) criteria for determining patients at risk of RFS. In addition, Mini Nutritional Assessment Short Form (MNA®-SF) was used to identify patients at risk of malnutrition. Weight and height were assessed. The degree of weight loss was obtained by interview. Serum phosphate, magnesium, potassium, sodium, calcium, creatinine and urea were analyzed according to standard procedures. RESULTS: Of 342 older participants included in the study (mean age 83.1 ± 6.8, BMI range of 14.7-43.6 kg/m2), 239 (69.9%) were considered to be at risk of RFS, in which 43.5% and 11.7% were at risk of malnutrition and malnourished, respectively, according to MNA-SF. Patients in the risk group had significantly higher weight loss, lower phosphate and magnesium levels. In a multivariate logistic regression analysis, low levels of phosphate and magnesium followed by weight loss were the major risk factors for fulfilling the NICE criteria. CONCLUSION: The incidence of risk factors for RFS was relatively high in older individuals acutely admitted in geriatric hospital units, suggesting that, RFS maybe more frequent among older persons than we are aware of. Patients with low serum levels of phosphate and magnesium and higher weight loss are at increased risk of RFS. The clinical characteristics of the older participants at risk of RFS indicate that these patients had a relatively poor nutritional status which can help us better understand the potential scale of RFS on admission or during the hospital stay.

Definition of new cut-offs of BMI and waist circumference based on body composition and insulin resistance: differences between children, adolescents and adults.

OBJECTIVE: This study aims to determine associations between anthropometric traits, regional fat depots and insulin resistance in children, adolescents and adults to define new cut-offs of body mass index (BMI) or waist circumference (WC). DESIGN: Cross-sectional data were assessed in 433 children, adolescents and adults (aged: 6-60 years, BMI: 23.6 [21.0-27.7] kg m-2). Total adipose tissue (TAT), regional subcutaneous adipose tissue (SATtotal, SATtrunk) and visceral adipose tissue (VAT) were determined by whole-body magnetic resonance imaging, fat mass by air-displacement plethysmography. Insulin resistance was evaluated by homeostasis model assessment of insulin resistance (HOMA-IR). Bivariate as well as partial correlations and regression analyses were used. Cut-off values of BMI and WC related to regional fat depots and HOMA-IR were analysed by receiver operating characteristics curve. RESULTS: In adults, TAT, SATtotal and SATtrunk increased linearly with increasing BMI and WC, whereas they followed a cubic function in children and adolescents with a steep increase at BMI and WC ≥1 standard deviation score and VAT at WC ≥2 standard deviation score. Sex differences were apparent in adults with women having higher masses of TAT and SAT and men having higher VAT. Using established BMI or WC cut-offs, correspondent masses of TAT, SATtotal, SATtrunk and VAT increased from childhood to adulthood. In all age groups, there were positive associations between BMI, WC, SATtrunk, VAT and HOMA-IR. When compared with normative cut-offs of BMI or WC, HOMA-IR-derived cut-offs of regional fat depots were lower in all age groups. CONCLUSIONS: Associations between BMI, WC and regional fat depots varied between children, adolescents, young and older adults. When compared with BMI-derived and WC-derived values, an insulin resistance-derived cut-off corresponded to lower masses of regional fat depots. Thus, established BMI and WC cut-offs are not appropriate to assess metabolic disturbances associated with obesity; therefore, new cut-offs of BMI and WC are needed for clinical practice.

Quantification of whole-body and segmental skeletal muscle mass using phase-sensitive 8-electrode medical bioelectrical impedance devices.

BACKGROUND/OBJECTIVES: Bioelectrical impedance analysis (BIA) provides noninvasive measures of skeletal muscle mass (SMM) and visceral adipose tissue (VAT). This study (i) analyzes the impact of conventional wrist-ankle vs segmental technology and standing vs supine position on BIA equations and (ii) compares BIA validation against magnetic resonance imaging (MRI) and dual X-ray absorptiometry (DXA). SUBJECTS/METHODS: One hundred and thirty-six healthy Caucasian adults (70 men, 66 women; age 40±12 years) were measured by a phase-sensitive multifrequency BIA (seca medical body composition analyzers 515 and 525). Multiple stepwise regression analysis was used to generate prediction equations. Accuracy was tested vs MRI or DXA in an independent multiethnic population. RESULTS: Variance explained by segmental BIA equations ranged between 97% for total SMMMRI, 91-94% for limb SMMMRI and 80-81% for VAT with no differences between supine and standing position. When compared with segmental measurements using conventional wrist-ankle technology. the relationship between measured and predicted SMM was slightly deteriorated (r=0.98 vs r=0.99, P<0.05). Although BIA results correctly identified ethnic differences in muscularity and visceral adiposity, the comparison of bias revealed some ethnical effects on the accuracy of BIA equations. The differences between LSTDXA and SMMMRI at the arms and legs were sizeable and increased with increasing body mass index. CONCLUSIONS: A high accuracy of phase-sensitive BIA was observed with no difference in goodness of fit between different positions but an improved prediction with segmental compared with conventional wrist-ankle measurement. A correction factor for certain ethnicities may be required. When compared with DXA MRI-based BIA equations are more accurate for predicting muscle mass.

Impact of weight loss-associated changes in detailed body composition as assessed by whole-body MRI on plasma insulin levels and homeostatis model assessment index.

BACKGROUND/OBJECTIVES: We assessed the effect of weight loss-associated changes in detailed body composition on plasma insulin levels and homeostatic model assessment (HOMA) index to calculate the magnitude of reduction in different adipose tissue depots required to improve insulin sensitivity. SUBJECTS/METHODS: A total of 50 subjects aged 20-69 years were studied. The participants were compiled from low-calorie diet interventions and bariatric surgery and differed in their baseline body mass index (BMI; range 21.6-54.4 kg/m2) and degree of weight losses (range -3.3 to -56.9 kg). Detailed body composition and liver fat were measured using whole-body magnetic resonance imaging (MRI). Insulin resistance was assessed by HOMA. RESULTS: Mean body weight decreased by -16.0±13.6 kg. Significant changes were observed in total adipose tissue (TATMRI, range -0.5 to -36.0 kg), total subcutaneous adipose tissue (SATMRI), visceral adipose tissue (VATMRI), skeletal muscle, liver fat, plasma insulin levels and HOMA. Decreases in insulin and HOMA were correlated with reductions in TATMRI, SATMRI, VATMRI (just with HOMA) and liver fat. Losses of 2.9 and 6.5 kg body weight, 2.0 and 5.0 kg TATMRI as well as 1.6 and 6% liver fat were required to decrease plasma insulin levels by 1 µU/ml and HOMAadjusted for baseline HOMA by 1 point. Multiple regression analysis showed that baseline liver fat and changes in liver fat explained 49.7% and 55.1% of the variance in weight loss-associated changes in plasma insulin and HOMA, respectively. CONCLUSIONS: Decreases of adipose tissues and liver fat are the major determinants of reduction in plasma insulin levels and improvement in HOMA index.

Assessment and definition of lean body mass deficiency in the elderly.

Although the effect of age on body composition has been intensively discussed during the past 20 years, we do not have a uniform definition of sarcopenia. A suitable definition of low, lean body mass should be based on magnetic resonance imaging (MRI) estimates of muscle mass. Using recent MRI data of a population of 446 healthy free-living Caucasian volunteers (247 females, 199 males) age 18-78 years, a low skeletal muscle mass and sarcopenia were defined as a skeletal muscle mass >1 and >2 s.d. below the mean value obeserved in younger adults at age 18-39 years. The cutoffs for low muscle mass according to the skeletal muscle index (skeletal muscle mass/(height)(2)) or the appendicular skeletal muscle mass index (skeletal muscle mass of the limbs/(height)(2)) were 6.75 or 4.36 kg/m(2) for females and 8.67 or 5.54 kg/m(2) for males, respectively. On the basis of these cutoffs, prevalences of sarcopenia in the group of adults at >60 years are calculated to be 29% in females and 19.0% in males. Faced with different sarcopenic phenotypes (that is, sarcopenia related to frailty and osteopenia; sarcopenic obesity related to metabolic risks; cachexia related to wasting diseases), future definitions of sarcopenia should be extended to the relations between (i) muscle mass and adipose tissue and (ii) muscle mass and bone mass. Suitable cutoffs should be based on the associations between estimates of body compositions and metabolic risks (for axample, insulin resistance), inflammation and muscle function (that is, muscle strength).

Effect of weight loss and regain on adipose tissue distribution, composition of lean mass and resting energy expenditure in young overweight and obese adults.

BACKGROUND: Although weight cycling is frequent in obese patients, the adverse consequences on body composition and an increased propensity to weight gain remain controversial. OBJECTIVE: We investigated the effect of intentional weight loss and spontaneous regain on fat distribution, the composition of lean mass and resting energy expenditure (REE). DESIGN: Weight regainers (≥ 30% of loss, n=27) and weight-stable subjects (within <± 20% of weight change, n=20) were selected from 103 overweight and obese subjects (body mass index 28-43 kg m(-2), 24-45 years) who passed a 13-week low-calorie diet intervention. REE and body composition (by densitometry and whole-body magnetic resonance imaging) were examined at baseline, after weight loss and at 6 months of follow-up. RESULTS: Mean weight loss was -12.3 ± 3.3 kg in weight-stable subjects and -9.0 ± 4.3 kg in weight regainers (P<0.01). Weight regain was incomplete, accounting for 83 and 42% of weight loss in women and men. Regain in total fat and different adipose tissue depots was in proportion to weight regain except for a higher regain in adipose tissue of the extremities in women and a lower regain in extremity and visceral adipose tissue in men. In both genders, regain in skeletal muscle of the trunk lagged behind skeletal muscle regain at the extremities. In contrast to weight-stable subjects, weight regainers showed a reduced REE adjusted for changes in organ and tissue masses after weight loss (P<0.001). CONCLUSION: Weight regain did not adversely affect body fat distribution. Weight loss-associated adaptations in REE may impair weight loss and contribute to weight regain.

Impact of body-composition methodology on the composition of weight loss and weight gain.

BACKGROUND/OBJECTIVES: We intended to (i) to compare the composition of weight loss and weight gain using densitometry, deuterium dilution (D2O), dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI) and the four-compartment (4C) model and (ii) to compare regional changes in fat mass (FM), fat-free mass (FFM) and skeletal muscle as assessed by DXA and MRI. SUBJECTS/METHODS: Eighty-three study participants aged between 21 and 58 years with a body mass index range of 20.2-46.8 kg/m(2) had been assessed at two different occasions with a mean follow-up between 23.5 and 43.5 months. Body-weight changes within < 3% were considered as weight stable, a gain or a loss of >3% of initial weight was considered as a significant weight change. RESULTS: There was a considerable bias between the body-composition data obtained by the individual methods. When compared with the 4C model, mean bias of D2O and densitometry was explained by the erroneous assumption of a constant hydration of FFM, thus, changes in FM were underestimated by D2O but overestimated by densitometry. Because hydration does not normalize after weight loss, all two-component models have a systematic error in weight-reduced subjects. The bias between 4C model and DXA was mainly explained by FM% at baseline, whereas FFM hydration contributed to additional 5%. As to the regional changes in body composition, DXA data had a considerable bias and, thus, cannot replace MRI. CONCLUSIONS: To assess changes in body composition associated with weight changes, only the 4C model and MRI can be used with confidence.

Integrating the geographic information system into cancer research.

Cancer control researchers seek to reduce the burden of cancer by studying interventions, their impact on defined populations, and the means by which they can be better used. The first step in cancer control is identifying where the cancer burden is elevated, which suggests locations where interventions are needed. Geographic information systems (GIS) and other spatial analytic methods provide such a solution and thus can play a major role in cancer control. The purpose of this article is to examine the impact of GIS on the direction of cancer research. It will consider the application of GIS techniques to research in cancer etiology.

Biological treatment of a dye solution by Macroalgae Chara sp.: effect of operational parameters, intermediates identification and artificial neural network modeling.

The potential of a macroalgae Chara sp. was investigated as a viable biomaterial for biological treatment of Malachite Green (MG) solution. The effects of operational parameters such as temperature, pH, initial dye concentration, reaction time and amount of algae on biological decolorization efficiency were studied. Biological treatment of MG solution by live and dead algae was compared. The reusability and efficiency of the live algae in long-term repetitive operations were also examined. The batch experiments results revealed the ability of algal species in biological degradation of the dye. The biological degradation compounds formed in this process were analyzed by UV-Vis, FT-IR and GC-Mass techniques. The degradation pathway of MG was proposed based on the identified compounds. In addition, an artificial neural network model was developed to predict the biological degradation efficiency. The findings indicated that ANN provides reasonable predictive performance (R(2)=0.970). The influence of each parameter on the variable studied was assessed, reaction time being the most significant factor, followed by temperature of the solution.

Application of microalga Chlamydomonas sp. for biosorptive removal of a textile dye from contaminated water: modelling by a neural network.

In this paper biosorption of triphenylmethane dye, C.I. Basic Green 4 (BG4), by Chlamydomonas species was investigated. The results obtained from batch experiments revealed the ability of Chlamydomonas sp. to remove BG4. The effects of operational parameters such as initial dye concentration, temperature, pH, reaction time and algal concentration on biosorptive decolorization efficiency were examined. An artificial neural network model was developed to predict the biosorptive decolorization of BG4 solution. The findings indicated that ANN provided reasonable predictive performance (R2 = 0.979). The influence of each parameter on the response was assessed, initial concentration of the dye being the most significant factor, followed by temperature.

Biological decolorization of dye solution containing Malachite Green by microalgae Cosmarium sp.

The potential of Cosmarium species, belonging to green algae, was investigated as a viable biomaterial for biological treatment of triphenylmethane dye, Malachite Green (MG). The results obtained from the batch experiments revealed the ability of algal species in removing dye. The effects of operational parameters (temperature, pH, dye concentration and algal concentration) on decolorization were examined. Optimal initial pH was determined 9. The stability and efficiency of the algae in long-term repetitive operations were also examined. Michaelis-Menten kinetics was used to describe the apparent correlation between the decolorization rate and the dye concentration. The optimal kinetic parameters, nu(max) and K(m) are 7.63 mg dye g cell(-1)h(-1) and 164.57 ppm, respectively. All assays were conducted in triplicates.

Biodegradation of dye solution containing Malachite Green: optimization of effective parameters using Taguchi method.

In this paper, optimization of biological decolorization of synthetic dye solution containing Malachite Green was investigated. The effect of temperature, initial pH of the solution, type of algae, dye concentration and time of the reaction was studied and optimized using Taguchi method. Sixteen experiments were required to study the effect of parameters on biodegradation of the dye. Each of experiments was repeated three times to calculate signal/noise (S/N). Our results showed that initial pH of the solution was the most effective parameter in comparison with others and the basic pH was favorable. In this study, we also optimized the experimental parameters and chose the best condition by determination effective factors. Based on the S/N ratio, the optimized conditions for dye removal were temperature 25 degrees C, initial pH 10, dye concentration 5 ppm, algae type Chlorella and time 2.5h. The stability and efficiency of Chlorella sp. in long-term repetitive operations were also examined.