The key to the treatment of septic shock is to provide adequate oxygen supply and improve tissue perfusion. Lactate and central venous oxygen saturation (ScvO) are commonly used as the indices of oxygen metabolism, but tissue hypoxia may still exist even when lactate and ScvOare within the normal range. Arteriovenous difference in carbon dioxide partial pressure (COgap) can accurately reflect oxygen delivery when ScvOis in the normal range. This article reviews the advantages and shortages of lactate, lactate clearance rate, ScvO, and COgap in evaluating tissue hypoxia, in order to provide a reference for treatment and severity evaluation of septic shock.
Carbon Dioxide ; blood ; Humans ; Lactic Acid ; metabolism ; Metabolic Clearance Rate ; Oxygen ; blood ; Shock, Septic ; metabolism

The purpose of this study was to test whether oxygen carriers could decrease tissue injury in a rat model of acute myocardial infarct. The study included 3 groups: SD rats in group II and group III were subjected to permanent occlusion of their left anterior descending coronary arteries; SD rats in group I were subjected to sham-operation. The success of modeling was assartained by ECG. Then the rats were given drug via caudal veins for 2 days. A quantitative evaluation was made with an automatic device for interpretation of cardiac troponin T (cTnT); heart staining was made for the calculation of myocardial infarction size (MIS); and myocardial tissue was taken and subjected to routine pathological hematoxylin-eosin (HE) staining for showing myocardial cell injury. cTnT in the sham-operation group was significantly lower by comparison with that in the model group (P < 0.01), and it was slightly lower in the oxygen carriers group than that in the model group, but there was no statistically significant difference (P = 0.18); MIS was significantly smaller in the sham-operation group than that in the model group (P < 0.01), and it was greater in the model rats than that in the oxygen carriers rats (P < 0.05). HE staining of myocardicum in the oxygen carriers group was significantly better than that in the model group (P < 0.01). The evidence suggested that oxygen carriers increased oxygen supply to ischemic myocardium, reduced the myocardial injury, and thus might offer a novel treatment of myocardial infarction.
Animals ; Blood Substitutes ; pharmacology ; Hemoglobins ; metabolism ; Male ; Myocardial Infarction ; metabolism ; Oxygen ; metabolism ; Rats ; Rats, Sprague-Dawley ; Troponin T ; metabolism

OBJECTIVETo study the change in regulation of cerebral blood flow (CBF) and cerebral metabolism rate (CMR) during selective head cooling (SHC) in newborn piglets.

METHODSSixteen newborn piglets, aged 5 approximately 7 days, were randomly assigned to one of the following three groups: SHC in normal piglets (n = 4), SHC after hypoxia-ischemia HI (n = 6) and normal temperature after HI (n = 6). Nasopharyngeal temperature was respectively reduced to 35 degrees C and then 32 degrees C in SHC group. HI was induced by using temporary occlusion of the bilateral carotid arteries and mechanical ventilation with low concentration of oxygen (6%) for 30 minutes. CBF was measured with color microspheres method. Mixed venous blood and arterial sample were collected at the same time from superior sagittal sinus and forelimb artery respectively for blood gas analysis, blood glucose and lactate measurement. Cerebral oxygenation metabolism rate (CMRO(2)), cerebral glucose metabolism rate (CMR(Glu)) and cerebral lactate production (CLP) were calculated.

RESULTSIn normal piglets, CBF, CMRO(2) and CMR(Glu) were significantly decreased at 35 degrees C and 32 degrees C respectively, while CLP did not change. When nasopharyngeal temperature decreased to 35 degrees C, The ratios of CBF/CMRO(2), CBF/CMR(Glu) and CBF/CLP did not significantly change, coupling of CBF and CMR was maintained. While nasopharyngeal temperature decreased to 32 degrees C, the ratios of CBF/CMR(Glu) and CBF/CLP significantly decreased. Maintained newborn piglets normal temperature after HI, the CBF and CMRO(2) were significantly reduced, while CMR(Glu) and CLP were markedly increased. The ratio of CBF/CMRO(2) increased, CBF/CMR(Glu) and CBF/CLP decreased. Uncoupling of CBF and CMR was observed. During SHC after HI, the same decrease was observed in CBF and CMR(Glu) and CLP was markedly reduced. The ratio of CBF/CMRO(2), CBF/CMR(Glu) and CBF/CLP were restored at 35 degrees C and 32 degrees C as compared to the same time point in normal temperature, respectively.

CONCLUSIONCBF and CMR decreased in normal piglets during SHC and coupling of CBF and CMR was maintained. After HI, CBF was reduced and the disturbance of cerebral oxygenation metabolism occurred. CBF and CMR was uncoupled. SHC after HI can improve CMR and correct uncoupling of CBF and CMR.

Animals ; Animals, Newborn ; metabolism ; Blood Glucose ; Brain ; blood supply ; metabolism ; Cerebrovascular Circulation ; Cold Temperature ; Hypothermia, Induced ; Hypoxia-Ischemia, Brain ; metabolism ; Lactic Acid ; blood ; Oxygen Consumption ; Swine ; metabolism

OBJECTIVETo observe oxygen uptake efficiency plateau (OUEP, i.e.highest V˙O2/V˙E) and carbon dioxide output efficiency (lowest V˙E/V˙CO2) parameter changes during exercise in normal subjects.

METHODSFive healthy volunteers performed the symptom limited maximal cardiopulmonary exercise test (CPET) at Harbor-UCLA Medical Center. V˙O2/V˙E and V˙E/V˙CO2 were determined by both arterial and central venous catheters. After blood gas analysis of arterial and venous sampling at the last 30 seconds of every exercise stage and every minute of incremental loading, the continuous parameter changes of hemodynamics, pulmonary ventilation were monitored and oxygen uptake ventilatory efficiency (V˙O2/V˙E and V˙E/V˙CO2) was calculated.

RESULTSDuring CPET, as the loading gradually increased, cardiac output, heart rate, mixed venous oxygen saturation, arteriovenous oxygen difference, minute ventilation, minute alveolar ventilation, tidal volume, alveolar ventilation and pulmonary ventilation perfusion ratio increased near-linearly (P < 0.05-0.01, vs.resting); arterial oxygen concentration maintained at a high level without significant change (P > 0.05); stroke volume, respiratory rate, arterial partial pressure of carbon dioxide, arterial blood hydrogen ion concentration and dead space ventilation ratio significantly changed none-linearly (compare resting state P < 0.05-0.01).OUE during exercise increased from 30.9 ± 3.3 at resting state to the highest plateau 46.0 ± 4.7 (P < 0.05 vs.resting state), then, declined gradually after anaerobic threshold (P < 0.05-0.01, vs.OUEP) and reached 36.6 ± 4.4 at peak exercise. The V˙E/V˙CO2 during exercise decreased from the resting state (39.2 ± 6.5) to the minimum value (24.2 ± 2.4) after AT for a few minutes (P > 0.05 vs.earlier stage), then gradually increased after the ventilatory compensation point (P < 0.05 vs.earlier stage) and reached to 25.9 ± 2.7 at peak exercise.

CONCLUSIONSCardiac and lung function as well as metabolism change during CPET is synchronous.In the absence of pulmonary limit, appearing before and after anaerobic threshold, OUEP and lowest V˙E/V˙CO2 could be used as reliable parameters representing the circulatory function.

Arteries ; Blood Gas Analysis ; Blood Pressure ; Carbon Dioxide ; metabolism ; Cardiac Output ; Exercise ; physiology ; Exercise Test ; Heart ; Heart Rate ; Hemodynamics ; Humans ; Lung ; Oxygen ; metabolism ; Oxygen Consumption

OBJECTIVETo observe the level of intracellular reactive oxygen species (ROS) in rats with severe burn and pulmonary microvascular endothelial cells (PMVECs) treated with serum of rat with burn injury, and to investigate the relationship between ROS and apoptosis of PMVECs.

METHODS(1) Twenty-four SD rats were divided into sham injury group ( n = 3) and burn group (n = 21) according to the random number table (the same grouping method below). Rats in burn group were inflicted with 30% TBSA full-thickness scald on the back, and rats in sham injury group were sham injured. Blood samples were collected from abdominal aorta at post injury hour 6, 12, 24, 36, 48, 60, 72 respectively from 3 rats of burn group. The serum content of ROS was assayed by ELISA. The same determination was performed in rats of sham injury group. (2) Five rats were subjected to scald injury as above, and burn serum was prepared 24 hours after injury. Another 5 rats without receiving any treatment were used to prepare normal serum. (3) Marginal pulmonary tissue was harvested from 20 SD young rats. Cells were cultured with tissue block method and indentified with immunohistochemical staining. The third passage of PMVECs in logarithmic phase were inoculated in 6-well plates and 12-well plates. PMVECs in both plates were divided into 4 groups: normal serum group, burn serum group, normal serum + MnTBAP group, and burn serum + MnTBAP group, with 3 wells in each group. Cells in the former 2 groups were respectively cultured with special nutrient solution of endothelial cells without serum added with 15% healthy rat serum or 15% burn rat serum. Cells in the latter 2 groups were cultured with the same culture conditions as in the former two groups correspondingly with addition of 100 µmol/L MnTBAP in the nutrient solution. After being cultured for 24 h, the content of ROS in PMVECs in 6-well plates was detected with flow cytometry. The apoptosis of PMVECs in 12-well plates was observed with acridine orange-ethidium bromide staining, and the apoptosis rate was calculated. Data were processed with one-way analysis of variance and LSD-t test.

RESULTS(1) The serum contents of ROS in rats of burn group were respectively (187 ± 21), (235 ± 22), (231 ± 25), (291 ± 20), (315 ±23) nmol/mL at post injury hour 24, 36, 48, 60, 72, which were significantly higher than that in sham injury group [(141 ± 19) nmol/mL, with t values respectively 7. 86, 9. 57, 13. 87, 14.98, 18.40, P values below 0.01]. (2) Primary cells grew slowly and showed a cobblestone appearance. After passages, cells grew with orderly distribution. The positive rate of coagulation factor VIII of cells was (96 ± 5)% , and thus they were identified as PMVECs. (3) In normal serum group, burn serum group, normal serum + MnTBAP group, and burn serum + MnTBAP group, the contents of ROS in PMVECs were respectively 798 ± 40, 1 294 ± 84, 763 ± 59, 926 ± 42 ( F =93.01, P <0.01), and the apoptosis rates of PMVECs were respectively (6.2 ± 1.3)%, (57.3 ± 6. 7)%, (3.7 ± 0. 8)%, (28.7 ± 5. 7)% (F = 224.50, P <0.01) after being cultured for 24 h. Compared with those of normal serum group, the content of ROS and apoptosis rate of PMVECs in burn serum group increased significantly (with t values respectively 10.40 and 49.06, P values below 0.01). The content of ROS and apoptosis rate of PMVECs in burn serum + MnTBAP group were significantly lower than those in burn serum group (with t values respectively 7.48 and 23.94, P values below 0.01).

CONCLUSIONSSerum content of ROS was increased in severely burned rats. Burn rat serum stimulation on PMVECs can lead to the increase of the intracellular ROS and induce apoptosis. However application of MnTBAP can scavenge ROS and reduce the apoptosis induced by burn rat serum.

Animals ; Apoptosis ; Burns ; blood ; therapy ; Endothelial Cells ; pathology ; Enzyme-Linked Immunosorbent Assay ; Lung ; blood supply ; Oxygen ; Rats ; Reactive Oxygen Species ; blood ; Serum ; metabolism

Utilizing the third-order polynomial curve fitted to the experimental data, which represents the relationship between cerebral blood flow (CBF) and mean artery blood pressure (MABP), we constructed a lumped-parameter dynamic model with 5 elements. In this model; the resistance is not constants it is determined by the fitted curve. We simulated the process of CBF autoregulation numerically by solving the govern equation of this model and got quite accurate results. Furthermore, we studied the influence of hemodynamic parameters on the CBF autoregulation by this model and proved that the characteristic resistance is the most important factor.
Blood Flow Velocity ; Blood Pressure ; physiology ; Cerebrovascular Circulation ; physiology ; Homeostasis ; Humans ; Hypotension ; physiopathology ; Models, Biological ; Oxygen ; metabolism ; Regional Blood Flow

OBJECTIVETo study the time dependent antioxidation changes of serum and sciatic nerve in rats intoxicated with acrylamide.

METHODSMale Wistar rats weighing 180 to 220 g were given acrylamide dissolved in physiological saline (40 mg/kg ip 3 days/week). The control groups received normal saline. The gait was observed and antioxidant indexes of rat serum and sciatic nerve were determined on 0, second, fourth, sixth, 10th week.

RESULTSWith the extension of the intoxication period, compared with the control, the contents of glutathione in serum and sciatic nerve gradually decreased (P < 0.05; after 6 and 10 weeks to 92% and 77%; after 2, 4, 6 and 10 weeks to 92%, 82%, 67% and 66%); the levels of malondialdehyde gradually increased (P < 0.05; after 4, 6 and 10 weeks to 113%, 118% and 120%; after 4, 6 and 10 weeks to 153%, 167%, 174%); the abilities of the resistance to reactive oxygen species gradually decreased (P < 0.05; after 10 weeks to 82%; after 6 and 10 weeks to 76% and 71%); the activities of glutathione peroxidase gradually increased (P < 0.05; after 2, 4, 6 and 10 weeks to 122%, 130%, 160% and 124%; after 4, 6 and 10 weeks to 134%, 152% 164%); the activities of glutathione reductase increased at early stage (P < 0.01; after 4 and 6 weeks to 300% and 217%; after 4 weeks to 142%) and decreased later (P < 0.01; 6 and 10 weeks to 59% and 33% in sciatic nerve); the activities of superoxide dismutase increased primitively (P < 0.05; after 2 weeks to 110%; after 4 weeks to 124%) and decreased later (P < 0.05; after 10 weeks to 85% in serum). The changes of antioxidant indexes in serum and sciatic nerve according to gait score were similar. The level of MDA in serum was in high correlation (P < 0.01) with that in sciatic nerve. The regression coefficients were 0.99 and 0.96 according to the administration time and gait score respectively.

CONCLUSIONThe changes of the antioxidant indexes in serum and sciatic nerve of rat treated with acrylamide are time dependent. The changes in serum and sciatic nerve are similar but those in sciatic nerve are more remarkable.

Acrylamide ; toxicity ; Animals ; Glutathione ; blood ; metabolism ; Glutathione Reductase ; blood ; metabolism ; Lipid Peroxidation ; drug effects ; Male ; Malondialdehyde ; blood ; metabolism ; Rats ; Rats, Wistar ; Reactive Oxygen Species ; blood ; metabolism ; Sciatic Nerve ; drug effects ; metabolism ; Superoxide Dismutase ; blood ; metabolism

P50 is an important parameter reflecting the binding and releasing oxygen properties of blood substitutes. In this study, based on the strong penetrating property of near infrared light and the mechanism involved in the pulsatile oxygen meter in clinic as well as on the ability for penetrating biodegradable polymers and detecting bovine hemoglobin encapsulated within the microcapsules, we have made an airproof and equilibrium apparatus to measure oxygen saturation and oxygen partial pressure. Subsequently, we have obtained the oxygen dissociation curve and P50 of the microcapsules loaded bovine hemoglobin in the light of oxyHemoglobin and deoxyHemoglobin with different spectrum in the near infrared region. The above-mentioned apparatus and method are not destructive to the microcapsules, and the process is simple and nondestructive. So it is practical to take in-situ measurements of the oxygen binding and releasing property of biodegradable polymer microcapsules intented for the blood substitute.
Animals ; Biodegradation, Environmental ; Blood Substitutes ; analysis ; chemistry ; Capsules ; Cattle ; Hemoglobins ; metabolism ; Humans ; Oxygen ; analysis ; metabolism ; Oxyhemoglobins ; metabolism ; Polymers ; chemistry

OBJECTIVETo investigate oxidative stress in chronic hepatitis B (CHB) patients with elevated serum total bilirubin (TBIL).

METHODS75 CHB patients with elevated serum TBIL were enrolled in the present study. A, B, C, D and E group were defined. Serum Malondialdehyde (MDA), Xanthine Oxidase (XOD), Vitamin C (V(C)) and Vitamin E (V(E)) were determined. The control group contained 11 healthy donors and the carrier group contained 16 Hepatitis B surface antigen (HBsAg) carriers.

RESULTSThe concentrations of MDA and XOD were significantly higher in each group of patients than in the control (P < 0.05), while V(C) and V(E) were significantly lower (P < 0.05). The concentration of XOD was significantly higher in the carrier group than in the control (P < 0.05), while MDA, V(C) and V(E) were not significantly different (P > 0.05). The concentrations of MDA and XOD were significantly positively correlated with TBIL (r = 0.670, P < 0.01; r = 0.737, P < 0.01, respectively) in the patients, while V(C) and V(E) were significantly negatively correlated with TBIL (r = -0.463, P < 0.01; r = -0.247, P < 0.05, respectively). The concentration of MDA was significantly different among all the groups in the patients except the comparison between group A and group B. The concentration of XOD was significantly different between group A, B, C and group D, E (P < 0.05). The concentration of V(C) was significantly different between group A and group D, E and between group B, C, D and group E (P < 0.05). The concentration of V(E) was significantly different between group A, B and group E (P < 0.05).

CONCLUSIONThere was a disturbance between oxidative stress and anti-oxidative ability in CHB patients with elevated serum TBIL. Oxidative stress became more serious along with the increasing of serum TBIL. In HBsAg carriers, oxidative stress level was low. The results suggest antioxidant treatment for CHB patients with elevated serum TBIL may help to improve the effect of therapy.

Adolescent ; Adult ; Bilirubin ; blood ; Female ; Hepatitis B, Chronic ; blood ; metabolism ; Humans ; Male ; Malondialdehyde ; metabolism ; Middle Aged ; Oxidative Stress ; physiology ; Reactive Oxygen Species ; metabolism ; Vitamin E ; metabolism ; Young Adult

The errors in the measurement of blood gas analysis are loss of CO2 by exposure to atmospheric air, effects of the anticoagulant itself, temperature differences between the experimental subject and the measuring electrode, and metabolic changes which occur between sampling and measurement. The errors due to these metabolic processes may be minimized by transferring samples from the subject to the measuring electrode as quickly as possible. This is net always feasible, The effect of delay in estimation was studied in 22 patients who were taken elective operation or respiratory care with arterial line in situ. The syringes were stored at 0 -4degrees C (refrigerator) and 20-24degrees C(room temperature), and samples fur analysis were taken at intervals through 3 hours. We obtained the following results. 1) The partial pressure of oxygen fell significantly by 20 minutes at 0-4degrees C and 10 minutes at 20-24degrees C. 2) Oxygen disappeared from blood in the group with PO2 above 150 mmHg. The rate of disappearance was 18 mmHg/hr at 0-4degrees C and 42 mmHg/hr at 20-24degrees C. 3) PaCO2 increased significantly by 180 minutes at 0-4degrees C and 10 minutes at 20-24degrees C. 4) The rate of PaCO2 rise was 0.6 mmHg/hr at 0-4degrees C and 1.2 mmHg/hr at 20-24 degrees C. 5) Blood pH decreased significantly by 60 minutes at 0-4degrees C and 20 minutes at 20-24degrees C. 6) Bicarbonate, arterial O2 saturation and O2 content were not changed. So we highly recommend that blond gas analysis should be performed as soon as possible after sampling, especially within 10 minutes.
Blood Gas Analysis ; Electrodes ; Humans ; Hydrogen-Ion Concentration ; Metabolism ; Oxygen ; Partial Pressure ; Syringes ; Vascular Access Devices