1.Expression of chemokine receptor CXCR4 in hepatocellular carcinoma
Hui LIU ; Wei-Ping ZHOU ; Si-Yuan FU ; Meng-Chao WU ;
Academic Journal of Second Military Medical University 2000;0(11):-
Objective:To investigate the expression of chemokine receptor CXCR4 in hepatocellular carcinoma tissues,hepatocellular carcinoma cell line-MHCC97,human umbilical vein endothelial cells(HUVECs)and the ascites level of CXCL12,ligand of CXCR4,so as to lay a foundation for studying the role of CXCR4 in the metastasis of hepatocellular carcinoma.Methods:The expression of CXCR4 mRNA and protein was examined by RT-PCR and Western blotting in 21 specimens of hepatocellular carcinoma tissues,MHCC97 cells,HUVECs,and 17 specimens of normal hepatic tissues.Meanwhile,the levels of CXCL12 in ascitic fluids were assayed by ELISA in 18 hepatic cancer patients.Results:The relative expression values of CXCR4 mRNA in hepatocellular carcinoma tissues,MHCC97 cells,and HVECs were 2.21?1.09,2.14?1.15 and 1.72?1.20,respectively;and those of CXCR4 protein were 1.51?0.12,1.76?0.25,and 1.89?0.24,respectively;and those of CXCR4 protein were 1.51?0.12,1.76?0.25,and 1.89?0.24,respectively.CXCR4 mRNA and protein were not detected in normal hepatic tissues.ELISA results showed that the 18 hepatocellular carcinoma samples had a CXCL12 concentration range of 783-8 364 pg/ml(median value 6 871 pg/ml)in ascitic fluids.Conclusion:CXCR4 is highly expressed in the hepatocellular carcinoma tissues and cells,which is not associated with the clinical staging of the cancer.The elevated CXCL12 level in the ascitic fluid of cancer patients indicate that CXCR4 may play an important role in the metastasis of hepatocellular carcinoma.
2.Gastric fistulation with transcutaneous endoscopy in a child.
Zhi-hong HU ; Ming SHEN ; Li SUN ; Rong QIAO ; Fu-mei JIA ; Si-yuan YANG
Chinese Journal of Pediatrics 2004;42(3):222-223
3.Two methods of hepatic vascular exclusion for hepatectomy
Wei-Ping ZHOU ; Ai-Jun LI ; Si-Yuan FU ; Ze-Ya PAN ; Yuan YANG ; Liang TANG ; Meng-Ehao WU
Chinese Journal of General Surgery 2000;0(12):-
Objective To compare the effects of hepatic vein occlusion with tourniquet and Satinsky clamp in reseeting liver tumor involving the second hepatic portal.Methods From Jan 2003 to Jun 2006,180 patients underwent major liver resection with the selective hepatic vascular exclusion (SHVE).According to methods of hepatic vein occlusion,they were divided into two groups:Occlusion with tourniquet(tourniquet group,n=95)and occlusion with Satinsky clamp(Satinsky clamp group,n= 85).In tourniquet group,the hepatic veins were encircled and occluded with tourniquet,and in Satinsky clamp group,the hepatic veins were not encircled and clamped directly with Satinsky clamp.Data regarding the intraoperative and postoperative courses of the patients were analyzed.Results There was no difference between the two groups regarding the operating time,ischemia time,intraoperative blood loss and postoperative complications rate.The dissecting time of hepatic veins was significantly shorter in Satinsky group(6.2?2.4 min vs 18.3?6.2 min).lu the tourniquet group,five hepatic veins(one fight hepatic vein and four common trunk of left-middle hepatic veins)could not be dissected and encircled because of the tumors involving the cava hepatic junction.Another patient's common trunk of left-middle hepatic vein was inadvertently lacerated during the dissection.Hepatic veins in these 6 patients were occluded with Satinsky clamp successfully.Conclusion Occlusion with Satinsky clamping is safer and easier procedure than tourniquets in the resection of liver tumor involving the second porta hepatis.
4.Dose-dependent pharmacokinetic study of genistein in Beagle dogs.
Si-Yuan ZHOU ; Qi-Bing MEI ; Ru-Tao WANG ; Qing-Wei WANG ; Zhi-Fu YANG ; Si-Wang WANG
Acta Pharmaceutica Sinica 2005;40(6):553-556
AIMTo study the pharmacokinetics of genistein at different doses in Beagle dogs.
METHODSSuspended in 0.5% CMC-Na solution, genistein was orally administered to Beagle dogs at doses of 2.67, 5.34 and 10.68 mg.kg(-1). At various time intervals, 1.5 mL of blood was drawn from the femoral vein of dogs in their front legs. The plasma was treated with beta-glucuronidase. The genistein in plasma was extracted twice by vortexing with 2.0 mL mixture of methyl tert-tubtyl ether and pentane (v/v = 8:2). The organic phase was removed into the tubes and then evaporated in ventilation cabinet. The residue was dissolved in 50 microL of methanol. 20 microL solution was drawn and detected by high-performance liquid chromatography. The pharmacokinetic parameters were calculated by 3P97 software.
RESULTSThe plasma drug concentration-time data were fitted to the two-compartment model. When the dose was 2.67 mg.kg(-1), the MRT and AUC of parent compound were 52.9 min and 6.7 mg.min. L(-1), respectively. When the dose rose to 5.34 mg.kg(-1), the MRT and AUC of parent compound became 224.8 min and 26.1 mg.min.L(-1), respectively. However, when the dose increased to 10.68 mg .kg(-1), the MRT and AUC of parent compound increased to 267.7 min and 33.2 mg.min L(-1), respectively. The AUC of glucuronidated genistein was 33.9, 70.1 and 140.5 mg.min.L(-1) at the dose of 2.67, 5.34 and 10.68 mg.kg(-1), respectively.
CONCLUSIONDue to significant first pass metabolism, the drug was mainly existed in the form of glucuronidated genistein in the plasma. With the increase of dose, the absorption of genistein became saturated and the half life prolonged.
Animals ; Anticarcinogenic Agents ; administration & dosage ; blood ; pharmacokinetics ; Area Under Curve ; Dogs ; Dose-Response Relationship, Drug ; Female ; Genistein ; administration & dosage ; blood ; pharmacokinetics ; Glucuronides ; blood ; pharmacokinetics ; Male
5.Expression of thyroid-stimulating hormone receptor in mammary gland tissue of lactating rats
Si-yuan, WAN ; Li-xiang, LIU ; Mao-fu, WU ; Hong-mei, SHEN ; Ke-xin, LIU ; Yu, SUN
Chinese Journal of Endemiology 2013;(3):254-257
Objective To observe the protein and mRNA expression of thyroid-stimulating hormone receptor (TSHR) in mammary gland tissue of lactating rats,and to explore iodine uptake mechanism.Methods Eighty adult Wistar rats (60 female and 20 male),weighting 210-250 g were selected.All female Wistar rats were randomly divided into 6 groups according to their body mass:normal non-pregnant group,lactating for 5-,10-,15-and 20-day groups and weaning for 5 days group,10 rats in each group.All rats were fed with conventional fodder and tap water freely.In addition to the normal non-pregnant group,other five groups of female and male rats were mated at 3 ∶ 1,respectively.Then the rats in all groups were killed on the 5th,10th,15th and 20th day after lactation and on the 5th day after weaning to get the mammary gland tissue.The protein and mRNA expression of TSHR were determined by immunohistochemical staining and real-time quantitative PCR.Results TSHR protein was expressed in mammary acinar and ductal epithelial cytoplasm.The expression of TSHR in mammary gland showed significant differences between groups (x2 =14.612,P < 0.05),the staining intensity of mammary gland tissue in normal non-pregnant rats(weak,n =4; moderate,n =6) was weaker than that of lactating for 5 days(weak,n =2; moderate,n =3; strong,n =5) and 10 days groups(barely detectable,n =1;moderate,n =4; strong,n =5; x2 =4.113,5.250,all P< 0.05).The expression of TSHR mRNA in mammary gland showed significant differences between groups(F=20.488,P < 0.05); the expression of TSHR mRNA in lactating for 10 days group(0.31 ± 0.06) was higher than that of lactating for 5 days group(0.22 ± 0.04,P < 0.01),and the expression of lactating for 15 days group (0.16 ± 0.08) was significantly lower than that of lactating for 5 days group (P < 0.05).Conclusions TSHR is widely expressed in mammary gland of lactating rats.The iodine uptake of mammary gland is enhanced in early lactation period when the body may be more susceptible to iodine deficiency,therefore iodine should be supplemented reasonably.
6.Autopsy study for maxillary nerve and its artery supply
Yuan-Xin ZHANG ; Kui-Qi ZHANG ; Si-Jia QIN ; Fu WANG
Chinese Journal of Otorhinolaryngology Head and Neck Surgery 2012;47(10):836-840
Objective To observe the travel,divisions,and the lengths,diameters,branches,artery supplies of the main segments of maxillary nerve.Methods Fifty formalin-preserved adult half-head specimens with intravascular injection of red color emulsion were used for the gross and microanatomical studies of maxillary nerve.The lengths,diameters,branches and artery supplies of four main segments of maxillary nerve were observed.SPSS 11.5 software was used to analyze the data.Results The length and diameter of cranial middle fossa segment of maxillary nerve were ( 10.70 ± 1.31 ) mm and (4.01 ± 0.52 )mm respectively,which was supplied by inferior-lateral cavernous sinus artery.The length and diameter of pterygopalatine fossa segment were (16.21 ± 1.80) mm and (3.27 ±0.62) mm respectively,in which one zygomatic branch, one to three posterior superior alveolar nerves, two ganglion branches and tuberal descending branches; were given off,and the segment was supplied by foramen rotundum artery.The length and diameter of infraorbital segment were ( 25.73 ± 2.03 ) mm and ( 3.30 ± 0.52 ) mm and it gave off middle superior alveolar nerve (64%) and anterior superior alveolar nerve and was supplied by infraorbital artery.Facial segment gave off superior labial branches,internal and external nasal branches,inferior palpebral branches,buccal branch and zygomatic branch and these branches were supplied by infraorbital artery and superior labial and angular artery originating from facial artery.Conclusions Understanding of travel and artery supply of maxillary nerve is helpful to regional anaesthesia and surgery for maxillary nerve.Foramen rotundum,sphenopalatine foramen and infraorbital nerve are important marks for endoscopic surgery in pterygopalatine fossa.
7.Multi-center clinical observation of Zibei Zhike Granules on acute broncho-bronchitis
ming Jun FAN ; hui Xiao FAN ; yuan Fu FAN ; Bing MAO ; ping Si ZHENG ; yan Hong CAI
Chinese Traditional Patent Medicine 2017;39(10):2024-2029
AIM To observe the clinical effects and safety of Zibei Zhike Granules (Asteris Radix et Rhizoma,Ardisiae japonicae Herba,Fritiliariae cirrhosae Bulbus,etc.) for acute broncho-bronchitis with remained toxicity lingering lung.METHODS A multi-center,randomized,double-blinded,double-simulation and positive drug parallel controlled trial was adopted.Two hundred and forty cases of patients with the 1 ∶ 1 ratio were assigned to treatment and control group.The treatment group were treated with Zibei Zhike Granules and the control group were treated with Zikebao Tablets (Asteris Radix et Rhizoma,Citri rubrum exocarpium,Platycodi Radix,etc.).The treatment course lasted five days.RESULTS The total effective rate of acute broncho-bronchitis in the treatment group was 73.04%,and 54.78% in the control group.There was statistical significance between the total effective rate of the two groups (P < 0.01).The total effective rate of traditional Chinese medicine syndrome in the treatment group was 73.91% and 60.86% in the control group,and there was statistical significance between the total effective rate of the two groups (P < 0.05).The treatment group showed better clinical effects in improving individual symptoms of cough and spitting sputum.CONCLUSION Zibei Zhike Granules has good clinical effects on acute broncho-bronchitis.
8.Rat insulin-like growth factor- Ⅰ and transforming growth factor-β1 mRNA expression in thyroid and placenta with different iodine intakes during pregnancy
Rui-qiang, DONG ; Xue-jiao, WANG ; Hong-mei, SHEN ; Li-xiang, LIU ; Mao-fu, WU ; Ke-xin, LIU ; Si-yuan, WAN
Chinese Journal of Endemiology 2012;31(1):32-36
ObjectiveTo study the mRNA expression of rat Insulin-like growth factors- Ⅰ (IGF- Ⅰ ) and Transforming growth factor-β1 (TGF-β1) in thyroid and placenta with different iodine intakes during pregnancy.MethodsOne hundred and fifty female Wistar rats,weighting 80 - 100 g,were randomly divided into five groups according to body weight,30 rats in each group.Each group was given deionized water containing different concentrations of iodine,50 μg/L(control group,NI),0 μg/L(iodine deficiency 1 group,LI1 ),5 μg/L(iodine deficiency 2 group,LI2),3000 μg/L(iodine excess 1 group,HI1 ),and 10 000 μg/L(iodine excess 2 group,HI2),respectively.After feeding for 12 weeks,the female rats were mated with male rats.The female rats were sacrificed at first(6,7 days),trimester( 12,13 days),and third trimesters( 19,20 days),respectively,then their thyroid and placenta were collected.The mRNA expressions of IGF- Ⅰ and TGF-1 in thyroid and placenta were detected by real-time quantitative PCR.Results①The actual thyroid weights of LI1 and LI2 groups[ (12.17 ± 5.41 ) × 10-2 g,(3.54 ± 1.21) × 10-2 g] were significantly higher than that of NI group[ (2.05 ± 0.50) × 10-2 g,all P < 0.05] ;actual weights of HI1 and HI 2 groups[ (1.64 ± 0.27) × 10-2 g,(1.66 ± 0.29) × 10-2 g] were compared with that of NI group,the difference was not statistically significant(all P > 0.05).②The mRNA expression of IGF- Ⅰ: at the first trimester,LI1 and LI2 groups(l.98 ± 0.35,1.47 ± 0.22) were all higher than that of NI group(1.01 ± 0.18,all P< 0.01 ),HI1 and HI2 groups(0.68 ± 0.16,0.75 ± 0.09) were lower than that of NI group(all P < 0.01 );at the second trimester,HI2 group( 1.14 ± 0.17) was lower than that of NI group( 1.58 ± 0.33,P < 0.01 ) ; at the third trimester,LI2 and HI2 groups(1.47 ± 0.20,1.45 ± 0.35) were lower than that of NI group(2.20 ± 0.37,all P<0.01).The mRNA expression of IGF- I level in NI group at the first,second,and third trimesters(1.01 ±0.18,1.58 ±0.33,2.20 ± 0.37) was up regulated gradually,pairwise comparisons were statistically significant(all P < 0,01 ).③The mRNA expression of TGF-β1: at the first trimester,LI1 group (1.37 ± 0.13) was higher than NI group (1.05 ±0.18,P < 0.01 ),HI1 and HI2 groups(0.50 ± 0.09,0.44 ± 0.11) were lower than NI group(all P< 0.01); at the second trimester,LI1 and HI2 groups(1.39 ± 0.28,1.17 ± 0.12) were higher than NI group(0.63 ± 0.22,all P <0.01 ) ; at the third trimester,LI1 and LI2 groups ( 1.57 ± 0.30,1.23 ± 0.20) were higher than NI group ( 0.68 ± 0.17,all P< 0.01).TGF-β1 mRNA expressions of NI group at the second (0.63 ± 0.22) and third trimesters(0.68 ± 0.17) were lower than that of the first trimester (1.05 ± 0.18,all P < 0.01).④ Rats' IGF-Ⅰ mRNA expression in placental: at the second trimester HI1 group,HI2 group( 1.48 ± 0.16,1.45 ± 0.25) were all higher than the NI group ( 1.00 ± 0.10,all P < 0.01 ) ; at third trimester,HI1 group ( 1.75 ± 0.15 ) were higher than the NI group ( 1.54 ± 0.29,P< 0.05),HI2 group(l.94 ± 0.31) were higher than the NI group(P < 0.01 ).IGF- Ⅰ mRNA expression in placental of NI group at the third trimester was higher than the second trimester(P< 0.01).⑤ Rats' TGF-β1 mRNA expression in the placenta: at the second trimester and the third trimester of pregnancy there were no significant difference between the five groups(all P > 0.05) ; NI group at the third trimester(0.83 ± 0.16) was lower than the second trimester(0.98 ± 0.20,P < 0.05).Conclusions During pregnancy,IGF- I mRNA expression increases in thyroid under the conditions of iodine deficiency,and this effect is particularly significant in the first trimester; at the same time,TGF-β1 mRNA expression is increased,and this inhibition becomes clear with the deepening of iodine deficiency.Under the condition of iodine excess,the functions of IGF- Ⅰ and TGF-β1 in thyroid above-mentioned were relatively weak.With the development of gestational period,promoting tissues growth and differentiation effect of placenta's IGF- Ⅰ was more significant gradually,but,inhibited effect of TGF-β1 was weaken.
9.Effects of different iodine intakes on rat iodine metabolism during pregnancy
Rui-qing, DONG ; Xue-jiao, WANG ; Hong-mei, SHEN ; Li-xiang, LIU ; Mao-fu, WU ; Ke-xin, LIU ; Si-yuan, WAN ; Yu, SUN
Chinese Journal of Endemiology 2012;31(6):620-624
Objective To study the effects of different iodine intakes on rat iodine metabolism during pregnancy.Methods One hundred and fifty female Wistar rats (body weight 80-100 g) were randomly divided into five groups:control group(NI),lower iodine 1 and 2 groups(LI1 and LI2),High iodine 1 and 2 groups(HI1 and HI2) by weight,30 rats in each group.These rats were given deionized water containing different concentrations of iodine,50(NI),0 (LI1),5(LI2),3000(HI1) and 10000 μg/L(HI2),respectively.After 12 weeks,urine samples were collected before copulation.The rats were sacrificed at the first(6-7 days),second (12-13 days) and third trimesters(19-20 days),respectively,serum and amniotic fluid samples were collected.Urinary iodine and iodine level in the fetal amniotic fluid were measured by As3+-Ce4+ catalytic spectrophotometry.Serum iodine was measured by mild acid digestion method.Results The baseline medians of urinary iodine of LI1 and LI2 groups(5.96,15.92 μg/L) were significantly lower than that of the NI group(43.75 μg/L,all P < 0.01),and the values of HI and HI2 groups(5263.96,20389.64 μg/L) were significantly higher than that of the NI group (all P < 0.01).The median of urinary iodine during pregnancy was significantly lower than that of the baseline of no pregnancy(all P < 0.01).The medians of urinary iodine of the NI group at the first and the second trimesters (28.97,34.34 μg/L) were significantly lower than that of the third trimester(42.31 μg/L,all P < 0.01).The means of serum iodine of LI1 and LI2 groups[(3.68 ± 1.69),(10.45 ± 4.16) μg/L] were significantly lower than that of the NI group [(23.68 ± 3.85)μg/L,all P < 0.05],and the means of serum iodine of HI1 and HT2 groups [(502.67 ± 97.03),(822.15 ± 139.45)μg/L] were significantly higher than that of the NI group (all P < 0.01).Although the mean of serum iodine of HI group gradually decreased with the progression of gestation,the difference was not statistically significant(all P > 0.05).The iodine levels in amniotic fluid of fetal rats at the second and the third trimesters in LI1 group(0.85,3.00 μg/L) were significantly lower than that of the NI group(3.56,7.91 μg/L,all P < 0.01),but the difference was not statistically significant between the iodine level in amniotic fluid of fetal rats of the LI2 and the NI groups at the second and the third trimesters(all P > 0.05).The iodine levels in amniotic fluid of fetal rats at the second and the third trimesters in the HI1 group(49.59,171.21 μg/L) were significantly higher than that of the NI group(all P < 0.01).The iodine levels in amniotic fluid of fetal rats at the second and the third trimesters in HI2 group (98.76,544.77 μg/L) were significantly higher than that of the NI group(all P < 0.01).The iodine level in amniotic fluid of fetal rats in the third trimester was significantly higher than that of the second trimester in all the groups (all P < 0.01).The ratios of serum iodine and urinary iodine of the LI1 and the LI2 groups (1.29 ± 1.14,1.70 ± 1.01) were significantly higher than that of the NI group(0.51 ± 0.37,all P <0.01),and that of the HI1 and the HI2 groups(0.21 ± 0.07,0.11 ± 0.07) were significantly lower than that of the NI group (all P < 0.01).The ratios of amniotic fluid iodine and serum iodine of the LI and the LI2 groups (0.19 ± 0.15,0.32 ± 0.17) were significantly higher than that of the NI group(0.13 ± 0.05,P < 0.01),but the difference was not statistically significant between HI1 and HI2 groups(0.09 ± 0.03,0.11 ± 0.04) and NI group(all P > 0.05).The ratio of amniotic fluid iodine and serum iodine of the third trimester was significantly higher than that of the second trimester(all P < 0.05).Conclusions Different iodine intake leads to changes in the levels of maternal iodine metabolism in rats during pregnancy.There probably is a protection mechanism in the mother's body,which protects the mother and the fetal from injury by iodine excess or iodine deficiency.
10.The effect of different levels of iodine nutrition on rat maternal thyroid function during pregnancy
Ke-xin, LIU ; Hong-mei, SHEN ; Xue-jiao, WANG ; Rui-qiang, DONG ; Li-xiang, LIU ; Si-yuan, WAN ; Mao-fu, WU
Chinese Journal of Endemiology 2013;(3):245-249
Objective To observe the effect of different levels of iodine nutrition on rat maternal thyroid function during pregnancy.Methods A total of 225 Wistar rats one month after weaning were involved in the study(female 165,male 60,body mass 80 to 100 g).Female rats were randomly divided into six groups by body mass:control group(NI group),iodine deficiency 1 and 2 groups(LI1,LI2 groups),iodine excess 1 and 2 groups (HI1,HI2 groups),and the control of not pregnant group(NNI group).There were 30 rats in 1-5 groups and 15 rats in group 6.LI1,LI2 groups:low iodine diet + deionized water of no iodine or iodine-containing 5 μg/L; HI1,HI2 groups:normal diet + deionized water of iodine 3000,10 000 μg/L; NI,NNI groups:normal diet + deionized water of iodine-containing 50 μg/L.After 12 weeks,the females(except group 6) mated the male by 2 ∶ 1,and then each pregnant female rat was fed in a single cage.The female mice were sacrificed in the first(5 ± 2)d,the second (12 ± 2)d and the third trimesters of pregnancy (17 ± 2)d,respectively,and there blood samples and thyroid were obtained.Serum total thyroxine(TT4),free thyroxine(FT4),total triiodothyronine (TT3),free triiodothyronine (FT3) and thyroid stimulating hormone(TSH) were determined by radioimmunoassay and serum thyroglobulin(TG) and thyroid-binding globulin (TBG) were determined by enzyme-linked immunosorbent assay.Results ①Thyroid absolute quality and relative quality was compared among groups,and the differences were statistically significant (F =16.55,24.25,F < 0.01 or < 0.05).②At the first,the second and the third trimesters of pregnancy,the differences of maternal serum TT4 and FT4 between groups were statistically significant(F =5.02,13.41,17.39,41.89,23.72,48.64,P < 0.01 or < 0.05).Female rats in NI,HI1 and HI2 groups in different pregnant periods among inner groups were compared,and the differences of serum TT4 and FT4 were statistically significant(F=3.27,6.98,8.22,8.65,29.68,7.90,P < 0.01 or < 0.05).③ In the first and the third trimesters of pregnancy,maternal serum TT3 was compared among groups,and the differences were statistically significant(F=3.59,8.22,P < 0.05 or < 0.01) ; in the second and the third trimesters of pregnancy,maternal serum FT3 was compared among groups,and the difference was statistically significant(F =3.86,4.26,P < 0.05 or < 0.01).Female rats in NI,LI1 and HI1 groups in different pregnant periods among inner groups were compared,and the differences of maternal serum TT3 were statistically significant(F =8.77,7.11,6.28,P < 0.01 or < 0.05).④At the first,the second and the third trimesters of pregnancy,the differences of maternal serum TG and TBG were compared in groups,and the differences were statistically significant(F =5.47,3.62,9.35,4.15,13.16,22.78,P < 0.01 or < 0.05).The differences of maternal serum TG of HI1 group and of serum TBG of NI group in different pregnant periods among inner groups were statistically significant (F =3.18,7.94,P < 0.05).⑤At the first,the second and the third trimesters of pregnancy,the differences of maternal serum TSH in groups were statistically significant(F =4.83,7.08,6.52,P < 0.01); the differences of maternal serum TSH of all the 5 groups in different pregnant periods among inner groups were statistically significant (F =3.26,8.89,11.45,4.04,3.78,P < 0.05).Conclusions Different levels of iodine nutrition can cause changes in thyroid function in rats maternal thyroid function during pregnancy; serum TT4,FT4 level decreases when iodine deficiency,and increase with iodine excess.Serum TT3,FT3 level of does not changed significantly due to compensatory regulation of the body.