Changes of interleukin-6 and related factors as well as gastric intramucosal pH during colorectal and orthopaedic surgical procedures.

OBJECTIVE: To investigate the changes of perioperative serum levels of interleukin-6 (IL-6), C-reactive protein (CRP), and cortisol, as well as gastric intramucosal pH (pHi) and plasma lactate, aiming to compare systemic changes and tissue perfusion during colorectal and orthopaedic surgical procedures. METHODS: Twenty patients were randomly assigned to two groups, 10 cases of operation on vertebral canal, 10 cases of colorectal radical operation. Venous blood was drawn at 1 day before operation, 2, 4, and 6 hours following skin incision, and 1 day after operation, in order to measure serum IL-6, CRP, and cortisol. pHi and plasma lactate were also measured at the same time points. RESULTS: Serum concentrations of IL-6 and cortisol increased gradually following operation, reaching the peak value at 6 hours from the beginning of operation. CRP was not detectable until the first day after operation. Peak concentration of IL-6 had positive relationship with CRP. These variables changed more significantly in colorectal group than that in orthopaedic group (P < 0.05). pHi decreased gradually, reaching the lowest level at 4 hours from the beginning of operation, and to more extent in colorectal group than that in orthopaedic group (P < 0.05). CONCLUSION: IL-6 may reflect tissue damage more sensitively than CRP. Colorectal surgery might induce systemic disorder to more extent, in terms of immuno-endocrinal aspect as well as tissue perfusion, reflected with pHi.

[Orexin A and neuropeptide Y levels in plasma and hypothalamus of rats with chronic renal failure].

OBJECTIVE: To explore the changes of orexin A and neuropeptide (NPY) in plasma and hypothalamus of rats with chronic renal failure (CRF). METHODS: 41 male Wister rats weighing 200 approximately 250 g were randomly divided into three groups: normal group, sham operation group, and CRF group (with the right kidney and 2/3 of the left kidney resected). A certain number of rats were decapitated 4, 8,and 12 weeks after respectively. Their hypothalami were removed and blood collected. Radioimmunoassay was used to measure the levels of orexin A and NPY in hypothalamus and plasma. Automatic biochemical analyzer was used to measure the serum creatinine. RESULTS: The serum creatinine level of CRF rats was both significantly higher than those of the sham operation rats at week 8 and week 12, respectively. The plasma orexin A level of CRF rats at week 12 was 264 pg/ml +/- 62 pg/ml, significantly higher than that of sham operation group (183 pg/ml +/- 56pg/ml, P = 0.039). The hypothalamus orexin A level of CRF rats were 10.5 fmol/mg +/- 2.7 fmol/mg wet weight at week 12, significantly lower than that of sham operation rats (17.4 fmol/mg +/- 3.9 fmol/mg wet weight, P = 0.023). The plasma NPY levels of CRF rats at week 8 and week 12 were significantly higher than those of the sham operation rats (7.1 pmol/ml +/- 1.7 pmol/ml vs 5.0 pmol/ml +/- 0.5 pmol/ml, P = 0.01; and 7.9 pmol/ml +/- 1.1 pmol/ml vs 4.8 pmol/ml +/- 1.1 pmol/ml, P = 0.0008). The hypothalamus NPY level of CRF rats at week 12 were 70 fmol/mg +/- 23 fmol/mg wet weight, significantly lower than that of the sham operation rats (113 fmol/mg +/- 31 fmol/mg wet weight, P = 0.03). CONCLUSION: Loss of renal function may diminish the excretion of orexin A and neuropeptide. The lowering of hypothalamus orexin A and neuropeptide Y levels may be one of the causes inducing anorexia in CRF.