Levels Of Serum Enzyme Activities Research Articles

Hepatoprotective Effects of Nasturtium Officinale and Allium Polyanthum Extracts on CCL4- Induced Hepatic Damage In Albino Rats

The aim: This study was designed to explore the potential hepatoprotective effects of Nasturtium officinale and Allium polyanthum plant extracts against CCl4-induced hepatic injury in rat model.
 Methods: Thirty healthy male albino rats were equally divided into 5 groups: Normal control (NC), Positive control (Pos-C), Nasturtium officinale extract (NOE), Allium polyanthum extract (APE), and NOE + APE. The animals were fed with a standard diet and distilled water ad libitum. Except for NC, all other groups were exposed to CCl4 at every 72 hours for 3 weeks to induce hepatic damage. Corresponding treatments were established to the respective groups during study period. Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Alkaline phosphatase (ALP), Total serum bilirubin (TSB), Total protein (TP), Albumin (ALB) and malondialdehyde (MDA) were measured in serum at the end of the study. Histopathological analysis of the liver sections was also determined.
 Results: CCl4-treated rats were showed significant increase (p < 0.05) in the levels of serum enzyme activities (AST, ALT, & ALP), TSB and MDA; reflecting the hepatocellular damage caused by CCl4 compared with NC rats, whereas the levels of TP and ALB were decreased. Furthermore, the histological examination of liver tissues showed that CCl4 triggered several histological variations in the liver tissues. Treatments of NOE and APE along with CCl4 for 3 weeks significantly (P<0.05) improved the CCl4-induced changes in serum biochemical parameters and liver histology as compared to Pos-C rats indicating the protection of hepatic cells.
 Conclusion: Treatments of NOE and APE either in separate or in combination have shown significant improvement in CCl4-induced hepatopathy in experimental rats as evidenced by observed results in serum and hepatic histopathological examinations

Evaluation of liver transaminases activities in lactating cows in different diet conditions

The aim of the study was to determine the correlation of liver transaminases’ activities levels in dairy cows in farm breeding with the parameters of milk gained after milking, in feeding conditions with and without the addition of sunflower oil. The study included 30 cows from the 2nd to 7th lactation divided into three groups with 10 heads in each. The first group (group A) consisted of cows at lower production level (13-15 kg of milk), the second group (group B) of cows at medium (19-21 kg of milk), and the third group (group C) of cows at higher production level (25-27 kg of milk). The cows were kept on a controlled feeding regime, common for lactating cows’ meals with the addition of sunflower oil. Milk control as well as milk and blood sampling were performed at the beginning, middle and at the end of the experiment, i.e. Day 1 (sampling 0), Day 21 (sampling 1) and Day 42 (sampling 2). Blood samples were taken by puncture of the V. jugularis with the aim of obtaining plasma and measuring liver transaminases: AST, ALT and ALP. Serum enzyme activity levels ranged within physiological limits. Statistically significant differences between groups of experimental cows were found after the addition of sunflower oil. Elevated level of AST activity was found in the context of a positive correlation with the amount of milk gained after milking in both feeding methods, i.e. with and without the addition of sunflower oil. Obtained results could indicate the necessary compensatory intensification of metabolic processes as a liver response to additional stress due to higher flow of fatty components.

Evaluation of Prophylactic and Therapeutic Effects of Silymarin on Phenobar- bital-Induced Hepatotoxicity in Cats

BACKGROUND: Phenobarbital is one of the most commonly used drugs to treat epilepsy and other seizure disorders in dogs and cats. Hepatotoxicity following phenobarbital administration is dose-dependent. OBJECTIVES: The present study aimed to evaluate the protective action of silymarin on phenobarbital-in- duced hepatotoxicity in cats. METHODS: For this purpose, twenty-four healthy adult cats were randomly allotted to four equal groups. Cats in group A were given phenobarbital with dosage 16 mg/kg orally for 28 days; group B received silymarin (30 mg/kg/day for twenty-eight days) orally concurrent with phenobarbital; groups C and D were treated like group B, but silymarin was administered 3 and 48 h after administration of phenobarbital, respectively, and continued up to twenty-eight days. The serum concentrations of alanine aminotransferase, aspartate amino- transferase, alkaline phosphatase, lactate dehydrogenase, total and direct bilirubin, blood urea nitrogen and creatinine were measured before administration of phenobarbital and after 24 h, 72 h and 28 days. RESULTS:Phenobarbital elevated significantly serum concentrations of liver enzymes (in all cases), and total and direct bilirubin in two cats of group A, after 24 h (P 0.05), while in group D, levels of serum enzyme activities (in 4 cases) were higher than the normal values (P<0.001). CONCLUSIONS: The results showed that silymarin can protect liver tissue against oxidative stress in cats with phenobarbital intoxication especially in the first 3 h post-exposure.

Screening of liver protective effect of ethanolic leaf extract of Callicarpa lanata (EECL) in ethanol induced hepatotoxicity in wister rats

Background: The ethanolic extract of Callicarpa lanata (EECL), belonging to the family Verbenaceae, were studied for hepatoprotective activity in Wister rats with liver damage induced by ethanol.Methods: Ethanol treated rats showed significant increase in the levels of serum enzyme activities, total bilirubin and reduction in total proteins reflecting the liver injury caused by ethanol. EECL, at a dose of 400 and 200mg/kg body weight exhibited hepatoprotective effect by lowering the Serum Glutamate Pyruvate Transaminase (SGPT), Serum Glutamate Oxaloacetate Transaminase (SGOT), Serum Alkaline Phosphate (SALP), Gama Glutamyl Transpeptidase (GGTP), total Bilirubin to a significant extent and also significantly increased the levels of total protein in a dose dependent manner.Results: The results were highly significant at dose level of 400mg/kg body weight (p &lt;0.01) and significant at dose level of 200mg/kg body weight (p &lt;0.05). The effects of EECL at both levels were comparable with standard drug silymarin. The hepatoprotective activity was also supported by histopathological studies of liver tissue.Conclusions: In-vivo hepatoprotective activity of ethanolic leaf extract of Callicarpa lanata (EECL) against Ethanol induced acute liver injury in rats showed significant results in a dose dependent manner.

Anti-hyperlipidemic and antioxidant effects of alkali-extractable mycelia polysaccharides by Pleurotus eryngii var. tuolensis

In this study, we noted that the Al-MPS from Pleurotus eryngii var. tuolensis provoked pharmacological effects on blood lipid profiles and oxidative stress. Animal studies demonstrated that Al-MPS showed potential effects on relieving hyperlipidemia and preventing oxidative stress, reflecting by decreasing the levels of serum enzyme activities (ALP, ALT and AST), restoring the activities of antioxidant enzymes (SOD, GSH-Px, CAT and T-AOC), down-regulating the MDA and LPO contents, as well as remitting the hepatic and cardiac tissues injury, respectively. The serum levels of TC, TG, LDL-C, VLDL-C, and HDL-C on mice treated with Al-MPS (500mg/kg bw) reached 2.48±0.08, 1.24±0.03, 0.84±0.02, 0.34±0.02, and 1.80±0.03mmol/L, which were lower/higher against the hyperlipidemia mice. The results clearly indicated that the Al-MPS could be used as a beneficial health food and potentially natural candidate medicine in preventing the high-fat emulsion-induced hyperlipidemia.

γ-Glutamyl Transferase Is Associated with Mortality Outcomes Independently of Fatty Liver.

High serum enzyme activity levels of γ-glutamyl transferase (GGT) are associated with increased risk of mortality, but whether this is mediated by fatty liver, as a common cause of high GGT levels, is uncertain. Our aim was to test whether GGT levels are associated with all-cause, cancer, and cardiovascular (CVD) mortality, independently of fatty liver. In an occupational cohort (n = 278 419), causes of death (International Statistical Classification of Diseases and Related Health Problems, 10th revision) were recorded over 7 years. Liver function tests and liver fat [measured by ultrasonographic standard criteria or fatty liver index (FLI)] were assessed at baseline. We used Cox proportional hazards models to estimate adjusted hazard ratios (HRs) and 95% CIs of all-cause, cancer, and CVD mortality for GGT quartiles (with lowest GGT quartile as reference). There were 136, 167, 265, and 342 deaths across increasing GGT quartiles. After adjusting for liver fat (by ultrasound diagnosis) in the fully adjusted model, all-cause and cancer mortality were increased in the highest GGT quartile [HR 1.50 (95% CI 1.15-1.96) and 1.57 (1.05-2.35), respectively]. For CVD mortality, the hazard was attenuated: HR 1.35 (95% CI 0.72-2.56). After adjusting for FLI in the fully adjusted model, HRs for all-cause, cancer, and CVD mortality were 1.46 (0.72-2.56), 2.03 (1.02-4.03), and 1.16 (0.41,3.24), respectively. There were similar hazards for all-cause and cancer mortality and attenuated hazards for CVD mortality for people in the highest GGT quartile, adjusting for fatty liver assessed by either ultrasound or FLI.

Effect of prebiotic mannan oligosaccharide on hematological and blood serum biochemical parameters of cultured juvenile great sturgeon (Huso huso Linnaeus, 1754)

Summary The nutritional effects of prebiotic mannan oligosaccharide were evaluated using hematological and blood serum biochemical parameters in cultured juvenile great sturgeon (Huso huso). Fish were offered formulated diets containing two levels of prebiotic mannan oligosaccharide (2 and 4 g kg−1); a basal diet with no prebiotics was used as control. The experiment lasted for 46 days. Blood samples were collected from the caudal veins of 18 apparently healthy fish (average weight 217.77 ± 29.8 g) at the end of the trial. No significant differences were found in the serum enzyme activity levels between treatments (P > 0.05). However, adding mannan oligosaccharide as a supplement to the basal diet resulted in significant differences in lymphocytes and eosinophils between the control and the 2 g kg−1 treatment (P < 0.05) as well as a significant difference in the creatinine factor in the 2 g kg−1 mannan oligosaccharide treatment (P < 0.05). The results show that it would be advantageous to add 2 g kg−1 mannan oligosaccharide to the diets of juvenile great beluga sturgeon (Huso huso).

EVALUATION OF HEPATOPROTECTIVE ACTIVITY OF AGLAIA ELEAGNOIDEA (A. JUSS) BENTH STEM EXTRACT AGAINST CARBON TETRACHLORIDE INDUCED HEPATOTOXICITY IN ALBINO RATS

Objective: The present study was intended to evaluate the hepatoprotective activity of hydro alcoholic extract of stem of Aglaia eleagnoidea (A. Juss) Benth. It is a medicinal plant found in the dense and moist forests in Western and Eastern Ghats, and also in many drier parts of Indian states like Andhra Pradesh, Karnataka, Kerala, Bihar, Andaman and Nicobar Islands. Method: The hydro alcoholic extract and its hexane, ethyl acetate and methanol fractions of Aglaia eleagnoidea (A. Juss) Benth., at the doses of 150,300 & 600 mg/kg and two isolated phytoconstituents (50mg/kg) was administered orally by suspending in Sodium CMC to the Wister albino rats with carbon tetra chloride(1ml/kg) induced hepatotoxicity. Silymarin (50mg/kg) was given as reference standard drug. This dose dependant study was followed by histopathological studies of ccl4 and plant extract treated liver tissue. Result: Studies of blood samples of carbon tetra chloride treated rats showed significant increase in the levels of serum enzyme activities, reflecting the liver injury caused by paracetamol. It was evident from the results that after treatment with the plant extract, there was a significant reduction in the levels of serum biochemical parameters serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT), alkaline phosphatase (ALKP) and total bilirubin (TBL) induced by carbon tetrchloride hepatotoxicity. The histopathological observations also showed that plant extract treated liver sections against carbon tetrchloride induced hepatotoxisity revealed the well preserved cellular architexture of the liver tissue. Conclusion: The present study indicates the potential hepatoprotective activity of Aglaia eleagnoidea stem and its bioactive phytoconstituents predominantly stigmasterol, ?-sitosterol, Daucosterol and unidentified polyphenols. These compounds probably by suppressing the activity of reactive oxygen species which cause cellular damage, there by offering protection to the targeted tissue against the hepatotoxicity induced by carbon tetra chloride in albino rats.

Hepatoprotective activity of Adina cordifolia against ethanol induce hepatotoxicity in rats

The acetone (AEAC) and aqueous extracts (AQEAC) of Adina cordifolia, belonging to the family Rubiaceae, were studied for hepatoprotective activity against Wister rats with liver damage induced by ethanol. It was found that AEAC and AQEAC, at a dose of 500 mg/kg body weight exhibited hepatoprotective effect by lowering the Serum Glutamate Pyruvate Transaminase (SGPT), Serum Glutamate Oxaloacetate Transaminase (SGOT), alkaline phosphate and total bilirubin to a significant extent and also significantly increased the levels of total protein. The hepatoprotective activity was also supported by histopathological studies of liver tissue. Since results of biochemical studies of blood samples of ethanol treated rats showed significant increase in the levels of serum enzyme activities, reflecting the liver injury caused by ethanol and blood samples from the animals treated with AEAC and AQEAC showed significant decrease in the levels of serum markers, indicating the protection of hepatic cells against ethanol induced hepatocellular injury. The effects of AEAC and AQEAC were comparable with standard drug silymarin.DOI: http://dx.doi.org/10.3329/icpj.v1i9.11619 International Current Pharmaceutical Journal 2012, 1(9): 279-284

Evaluation of prophylactic and therapeutic effects of silymarin on acute toxicity due to tetracycline severe overdose in cats: a preliminary study

Summary The aim of the present study was to determine the protective action of silymarin on acute toxicity due to tetracycline severe overdose in cats. Thirty healthy cats were randomly allotted into five equal groups. Cats in group A were given tetracycline (single dose 120 mg⁄kg, p.o.); group B consisted of cats that received silymarin (single dose 30 mg⁄kg, p.o.) concurrent with tetracycline administration; groups C, D and E were treated as group B, but silymarin was administered 4, 12 and 24 h after tetracycline administration, respectively. The serum concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), BUN, serum creatinine and total and direct bilirubin were measured before tetracycline administration and 4, 12, 24 and 72 h later. A single oral administration of tetracycline increased, significantly, serum concentrations of ALT, AST, ALP, LDH in all cats of group A, after 24 h (P 0.05). In group E, levels of serum enzyme activities were significantly higher than normal values (P<0.05). The difference was significant between groups A and E with groups B and C for the serum enzymes (P<0.05). In conclusion, silymarin can protect liver tissue against hepatotoxicity in cats with tetracycline severe overdose, particularly in the first 4 h after exposure.

Evaluation of Prophylactic and Therapeutic Effects of Silymarin on Diazepam-Induced Hepatotoxicity in Cats

Problem statement: Diazepam is commonly administered for seizure control and appetite stimulant in cats. Cats may develop acute fatal hepatic necrosis after receiving oral diazepam for several days. The aim of this study was to detect the protective action of silymarin on diazepam-induced hepatotoxicity in cats. Approach: About 25 healthy cats were randomly allotted to five equal groups. Animals in Group A were given diazepam (repeated dose 2.5 mg kg-1, p.o. q 12 h for 4 days); Group B consisted of cats that received silymarin (30 mg kg-1, p.o. q 12 h for 4 days) concurrent with diazepam administration; Group C were received silymarin like Group B, but 24 h after diazepam administration; Group D were received silymarin like Group C, but 48 h after diazepam administration; Group E were received silymarin like Group D, but 72 h after diazepam administration. The serum concentrations of Alanine Amino Transferase (ALT), Aspartate Aminotransferase (AST), Alkaline Phosphatase (ALP), Lactate Dehydrogenase (LDH) and total and direct bilirubin were measured before diazepam administration and 24, 48, 72 and 96 h later as indices of liver injury. Results: Repeated oral administration of diazepam significantly elevated serum concentrations of ALT, AST, ALP, LDH and total and direct bilirubin in cats of Group A, after 48 h. In both the Groups (B and C) receiving silymarin, levels of serum enzyme activities and total and direct bilirubin remained within the normal values, but the Group D and E which received silymarin 48 h and 72h later, levels of serum enzyme activities and total and direct bilirubin were increased with comparison to before diazepam administration. Conclusion: It was concluded that silymarin can protect liver tissue against oxidative stress in cats with diazepam intoxication particular in the first 24 h after exposure.

Evaluation of prophylactic and therapeutic effects of silymarin on mebendazole-induced hepatotoxicity in cats

The aim of this study was to determine the protective action of silymarin on mebendazole-induced hepatotoxicity in cats. Twenty five healthy cats were randomly allotted into five equal groups. Cats in group A were given mebendazole (single dose 200 mg⁄kg, p.o.); group B consisted of cats that received silymarin (single dose 30 mg⁄kg, p.o.) concurrent with mebendazole administration; groups C, D and E were treated as group B, but silymarin was administered 2, 12 and 24 h after mebendazole administration, respectively. The serum concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and total and direct bilirubin were measured before mebendazole administration and 2, 12, 24 and 72 h later as indices of liver injury. A single oral administration of mebendazole significantly elevated serum concentrations of ALT, AST, ALP, LDH (in all cases), and total and direct bilirubin in one cat in group A, after 24 h (P < 0.05). In groups B and C, levels of serum enzyme activities and total and direct bilirubin remained within normal values, but in group D, levels of serum enzyme activity (in four cases) were higher than normal values and total and direct bilirubin remained within the normal range. In group E, levels of serum enzyme activities (in all cats) and total and direct bilirubin (in one cat) were higher than normal values. In conclusion, silymarin can protect liver tissue against oxidative stress in cats with mebendazole intoxication particularly in the first 2 h after exposure.

Hepatoprotective Activity of Cucumis trigonus Roxb. Fruitagainst CCl4 Inducesd Hepatic Damage in Rats.

In India, a number of medicinal plants and their formulations are used to cure hepatic disorders in traditional systems of medicine. No systemic study has been done on protective effect of Cucumis trigonus Roxb. (Cucurbitaceae) to treat hepatic diseases. Protective action of C. trigonus fruit extracts was evaluated in this study in animal model of hepatotoxicity, which was induced by carbon tetrachloride. Forty two healthy female albino Wistar rats weighing between 180 and 200 g were divided in to seven groups of 6. Group 1 was normal control group; Group 2, the hepatotoxic group was given CCl4; Group 3 was administered standard drug (Liv-52); Groups 4-7 received pet. ether, chloroform, alcohol and aqueous fruit extract (300 mg/kg) with CCl4. The parameters studied were alanine transaminase, aspartate transaminase, alkaline phosphatase and serum bilirubin activities. The hepatoprotective activity was also supported by histopathological studies of liver tissue. Results of the biochemical studies of blood samples of CCl4 treated animals showed significant increase in the levels of serum enzyme activities, reflecting the liver injury caused by CCl4. Whereas blood samples from the animals treated with chloroform and aqueous fruit extracts showed significant and alcohol extract showed highly significant decrease in the levels of serum markers, indicating the protection of hepatic cells. The results revealed that alcoholic fruit extract of Cucumis trigonus could afford highly significant protection against CCl4 induced hepatocellular injury.

Evaluation of prophylactic and therapeutic effects of silymarin andN-acetylcysteine in acetaminophen-induced hepatotoxicity in cats

Cats most commonly receive toxic amounts of acetaminophen (APAP) because owners medicate them without consulting a veterinarian. The aim of this study was to compare the hepatoprotective action of silymarin and N-acetylcysteine (NAC) against APAP poisoning. Twenty healthy cats were randomly allotted to five equal groups. Animals in group A were given APAP (single dose 150 mg/kg, p.o.); groups B and C consisted of cats that received NAC (100 mg/kg, p.o.) or silymarin (30 mg/kg, p.o.) concurrent with APAP administration respectively; groups D and E were treated like groups B and C, respectively, but 4 h after APAP administration. The serum concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), methemoglobin, and total and direct bilirubin were measured before APAP administration and 4, 24, and 72 h later. A single oral administration of APAP significantly elevated serum concentrations of ALT, AST, ALP, LDH, methemoglobin, and total and direct bilirubin. In both the groups receiving APAP plus NAC or silymarin, levels of serum enzyme activities, methemoglobin, and total and direct bilirubin remained within the normal values. It was concluded that silymarin as well as NAC can protect liver tissue against oxidative stress in cats with an APAP intoxication.

Hepatoprotective Activity of Capparis spinosa Root Bark Against CCl4 Induced Hepatic Damage in Mice

Many hepatoprotective herbal preparations have been recommended in alternative systems of medicine for the treatment of hepatic disorders. No systematic study has been done on protective efficacy of Capparis spinosa (Capparidaceae) to treat hepatic diseases. Protective action of C. spinosa ethanolic root bark extract was evaluated in this study in an animal model of hepatotoxicity, which was induced by carbon tetrachloride. Healthy male mice (30-35 g body weight, 6-8 week old) were divided into 7 groups. Group 1 was normal control group; Group 2, the hepatotoxic group was given CCl 4 ; Group 3 was administered olive oil (vehicle); Groups 4-6 received different doses of ethanolic root bark extract (100, 200 & 400 mg/kg) with CCl 4 ; Group 7 was administered overdose of the extract (800 mg/kg). The parameters studied were alanine transaminase and aspartate transaminase activities and duration of sleep. The hepatoprotective activity was also supported by histopathological studies of liver tissue. Results of the biochemical studies of blood samples of CCl 4 treated animals showed significant increase in the levels of serum enzyme activities, reflecting the liver injury caused by CCl 4 . Whereas blood samples from the animals treated with ethanolic root bark extracts showed significant decrease in the levels of serum markers, indicating the protection of hepatic cells. The results revealed that ethanolic root bark extract of C. spinosa could afford significant dose-dependent protection against CCl 4 induced hepatocellular injury.

A study for prevention of chronic fatigue. part 2. effects of strenuous physical exercise performed in a training camp on serum enzyme activity levels and subjective fatigue.

The principal objective of this paper is to develop a simple and rapid method of estimating levels of fatigue so that chronic fatigue can be prevented. Long-distance runners belonging to a successful corporate team (Group A; 25 males) and representative runners at the prefectural level (Group B; 14 males) participated in this study. We examined the effects of strenuous physical exercise on serum enzyme activity and the fatigue level felt by the runners (subjective fatigue).The following parameters were measured on two consecutive mornings during a training period: physical characteristics, serum-biochemistry using the dry-chemistry method, and subjective fatigue determined using the questionnaire regarding subjective symptoms authorized by the Japan Association of Industrial Health and the Profile of Mood State (POMS). Group A was divided into A-Senior (17 males; highest performance level) and A-Freshman (8 males) subgroups according to the length of employment within the corporation (one year or more and less than one year, respectively).The levels of serum aspartate aminotransferase (AST) and creatine kinase (CK) were significantly lower in the A-Senior group than the other groups and this group displayed the "iceberg" POMS profile at both examinations. Some significant correlations between the elements of POMS and serum enzyme activity levels were observed among all three groups during both examinations. The decline of serum CK levels tended to accompany a decrease in "Fatigue" according to POMS among 9 of 17 members of the A-Senior group. This tendency between the A-Senior and the A-Freshman groups statistically differed according to theX - square analysis.Our results suggest that the effects of physical stress on serum enzyme activity levels and subjective fatigue are affected by performance levels. Physical fatigue seemed to be reflected by serum CK levels. Monitoring subjective fatigue while measuring serum enzyme activity levels using the dry-chemistry method immediately provides clinical value to players and coaches on site, and should therefore help to prevent a shift from "overreaching" to "overtraining".

Protection by boswellic acids against galactosamine/endotoxin-induced hepatitis in mice

In the present study, we investigated the in vivo effect of the acetyl-boswellic acids (ac-BA) after oral application on the galactosamine/salmonella endotoxin-induced liver damage in mice. The data indicate that pretreatment by ac-BA 1 hr before the intoxication substantially reduced increased levels of serum enzyme activities

SERUM-ENZYMES IN RELATION TO ELECTROCARDIOGRAPHIC CHANGES IN ACCIDENTAL HYPOTHERMIA

High levels of serum-enzyme activities, particularly of creatine kinase and " α-hydroxybutyrate dehydrogenase", have been found during a study of 25 patients with accidental hypothermia. The results suggest that accidental hypothermia causes profound cellular damage, particularly of skeletal and cardiac muscle. This may help to explain the high mortality and the characteristic changes in the electrocardiogram found in such circumstances. These findings may be important in the use of hypothermia in surgery.