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Biomedical subjects

Y Yang

Publications and source records attributed to Y Yang.

At least 307 records · Page 17Linked to original sources
PubMed2001

Effects of extrinsic positive end-expiratory pressure on work of breathing in patients with chronic obstructive pulmonary disease.

OBJECTIVE: To investigate the effects of extrinsic positive end-expiratory pressure (PEEPe) on work of breathing in patients with chronic obstructive pulmonary disease (COPD) and their corresponding mechanism. METHODS: Ten ventilated patients with COPD were included in the study. A Bicore CP-100 pulmonary monitor (Bicore Monitoring System, USA) was used for monitoring respiratory mechanics. First, dynamic intrinsic positive end-expiratory pressure (PEEPi, dyn) was measured when PEEPe was zero, which was called PEEPi, dynz. Then the PEEPe was set randomly at 0%, 40%, 60%, 80% and 100% of PEEPi, dynz respectively. Pulmonary mechanics and other parameters (heart rate, blood pressure and blood gas analysis) were measured 30 minutes after the level of PEEPe was changed. RESULTS: Work of breathing patient (WOBp), pressure time product, difference of esophageal pressure and PEEPi, dyn decreased significantly when PEEPe was applied, and continued decreasing as PEEPe was increased. Work of breathing ventilator increased significantly when PEEPe was increased to 80% and 100% of PEEPi, dynz. Significantly positive linear correlation was found between the changes in WOBp and in PEEPi, dyn. CONCLUSIONS: WOBp decreases gradually as PEEPe is increased. WOBp decreases by narrowing the difference between the alveolus pressure and the central airway pressure at the end of expiration when PEEPe is applied.

Aged↗
PubMed2001

Expression of oncoproteins c-fos and c-jun in hypertrophic scars and chronic dermal ulcers and their regulation of basic fibroblast growth factor.

OBJECTIVE: To explore the characteristics of oncoprotein expression of c-fos and c-jun in hypertrophic scars and chronic dermal ulcers and their regulation of basic fibroblast growth factor (bFGF). METHODS: Tissues of hypertrophic scars (n = 8), chronic dermal ulcers (n = 8) and normal skin (n = 5) were taken from 21 patients with burns and chronic dermal ulcers in operation. The ABC immunohistochemical method was used to characterize the gene product expression of c-fos, c-jun and bFGF in the above tissues. RESULTS: In normal skin, both c-fos and c-jun protein expression and bFGF protein expression were observed. The signals of both oncoproteins were localized mainly in subcutaneous fibroblasts, but, positive expression of the bFGF protein was mainly in keratinocytes. In hypertrophic scars, positive expression of both oncoproteins could be found mainly in fibroblasts, but bFGF was mainly in fibroblasts and endothelial cells. In chronic dermal ulcers, endothelial cells, some of inflammatory cells and fibroblasts were positive for both of oncoproteins, but the expression of bFGF was only seen in fibroblasts and endothelial cells. CONCLUSIONS: The results indicate that the interaction between both oncoproteins and bFGF exists, and the regulating action between protooncogenes and bFGF is a major course in wound healing. The different expressions of c-fos and c-jun gene products play an important role in regulate bFGF action, thus affecting wound healing.

Chronic Disease↗
PubMed2001

Effects of extrinsic positive end-expiratory pressure on cardiopulmonary function in patients with chronic obstructive pulmonary disease.

OBJECTIVE: To choose one optimal extrinsic positive end-expiratory pressure (PEEPe) for ventilated patients with chronic obstructive pulmonary disease (COPD) and to compare two methods for choosing the optimal level of PEEPe. METHODS: Ten ventilated patients with COPD were included in the study. First, static intrinsic positive end-expiratory pressure (PEEPi, st) was measured when PEEPe was zero, and the PEEPi, st was called PEEPi, stz. PEEPe at 0%, 40%, 50%, 60%, 70%, 80%, 90% and 100% of PEEPi, stz, respectively, were applied randomly. Respiratory mechanics, hemodynamics, and oxygen dynamics were recorded 30 minutes after the level of PEEPe was changed. RESULTS: When PEEPe was not higher than 80% of PEEPi, stz, no measurement changed significantly. When PEEPe was increased to 90% and 100% of PEEPi, stz, PEEPi, st, peak inspiratory pressure, plateau pressure, pulmonary capillary wedge pressure and central venous pressure increased significantly, P < 0.01. Cardiac output and left ventricular work index decreased significantly, P < 0.01. Oxygen delivery decreased significantly, P < 0.05. When PEEPe was increased to 100% of PEEPi, stz, the right ventricular work index decreased significantly, P < 0.05. CONCLUSION: Eighty percent of PEEPi, stz was the upper limit of PEEPe. The results of the two methods used to set the level of PEEPe were identical.

Aged↗
PubMed2001

Expression characteristics of c-fos, c-myc and bFGF in early burn tissue.

OBJECTIVE: To investigate the sequence and characteristics of expression of proto-oncogenes, c-fos, c-myc and endogenous basic fibroblast growth factor (bFGF), in burn tissue from rats. METHODS: A partial thickness burn of 30% TBSA was created on the backs of Wistar rats. Immunohistochemistry was used to detect the expression of these proteins in normal and burned skin at 3 hours, 6 hours, 1 day, 3 days, 7 days and 14 days postburn. RESULTS: Expression of c-fos, c-myc and bFGF was induced by the burn, but these three proteins showed different expression levels in sequence and distribution. Expression of c-fos increased and peaked at 3 hours postburn. Stain positive granules were distributed mainly in the cytoplasm of basal cells and the nuclei of fibroblasts. The expression of bFGF protein increased at 6 hours and peaked at 1 day postburn; it was distributed in the cytoplasm of fibroblasts. c-myc protein peaked at 3 days postburn and was also distributed in the cytoplasm of fibroblasts. CONCLUSIONS: Thermal injury can induce c-fos, c-myc and bFGF expression and show phasic control and regional distribution. The phasic expression of these three proteins indicates that there maybe a regulatory relationship between proto-oncogenes and growth factors in early burn. This may play an important role in late tissue repair.

Animals↗
PubMed2001

Apoptosis of renal tubular cells in congenital hydronephrosis.

OBJECTIVE: To assess apoptosis in congenital hydronephrosis and discuss its clinical significance. METHODS: Apoptosis was detected in 15 kidneys from children with congenital hydronephrosis (5 mild hydronephrosis, 5 moderate hydronephrosis and 5 severe hydronephrosis) using the electronmicroscope, in situ gap labeling of fragmented nuclear DNA and DNA fragmentation analysis. RESULTS: Apoptosis was seen in kidneys from children with congenital hydronephrosis. Margination of nuclear chromatin was identified and rounded apoptotic bodies were seen. The mean apoptotic index was 0.0941 +/- 0.017 in severe hydronephrosis, 0.0325 +/- 0.0169 in moderate hydronephrosis, and 0.0021 +/- 0.0031 in mild hydronephrosis. There was a significant difference between severe and moderate hydronephrosis (P = 0.0005), as well as between moderate and mild hydronephrosis (P = 0.0154). Moreover, with an increasing degree of hydronephrosis, the number of apoptotic cells also increased. Five kidneys with severe hydronephrosis and one kidney with moderate hydronephrosis showed typical apoptotic bands. CONCLUSION: Apoptosis might participate in damaging kidneys in children with congenital hydronephrosis.

Apoptosis↗
PubMed2001

[Experimental research of viscoelasticity of C2-T1 cervical vertebra].

This is a research on the characteristics of stress relaxation and creep of cervical vertebra (c2-t1) of fresh body (18 cases). The effect of stress relaxation and creep of cervical vertebra was detected by simulating front and back routes operation. Reduced curve and data in the constant strain and stress were obtained. By using regression analysis method the reduced relaxation and creep functions were acquired. The experimental result showed the decrease of viscoelasticity in simulating operation conditions.

Adult↗
PubMed2001

[A pilot study in treatment of systemic lupus erythematosus by autologous bone marrow transplant].

OBJECTIVE: To explore the clinical effect for treatment of SLE by autologous bone marrow transplantation(ABMT). METHODS: Three patients with refractory SLE were chosen. BM stem cells were harvested from the posterior superior iliac crests under epidural anesthesia and preserved in 4 degrees C. BM stem cells were reinfused after conditioned by CTX (120 mg/kg) and malphalan (140 mg/m(2)) or VP-16 (1.0 g/m(2)). G-CSF was used to help hematopoietic and immunologic reconstitution. RESULTS: These three patients had clinical remission after transplantation; the levels of immunoglobulins declined and complements rose up. Most of the auto-antibodies turned negative. Skin pathology in case 2 showed that the former tissue injury alleviated or disappeared. Moreover, myocardial hypertrophy and pericardial effusion also disappeared. CONCLUSIONS: (1) ABMT is obviously effective for SLE. The duration of remission remains to be decided in long-term follow up. (2) Mechanisms of improvement are possibly related to decrease of immunologic pathological cells in tissues after conditioning, reduction of the level of immunoglobulins and drop of the quantity of auto-antibodies.

Adolescent↗
PubMed2001

[The effects of extrinsic positive end-expiratory pressure on work of breathing in patients with chronic obstructive pulmonary disease].

OBJECTIVE: To study the effect of extrinsic positive end-expiratory pressure(PEEPe) on work of breathing in chronic obstructive pulmonary disease (COPD) patients and its mechanism. METHODS: 10 ventilated patients [4 males and 6 females with mean age of (70.1 +/- 5.5) years] with exacerbation of COPD were admitted into the study. All the patients' cardiopulmonary functions were stable, and they could receive pressure support ventilation (PSV). Patients with sever heart dysfunction, hepatic dysfunction, renal dysfunction or fever were ruled out. Each patient had an esophagus balloon pressure sensor inserted, and the esophagus balloon was properly positioned using "occlusion test". Flow sensor was placed at the end of tracheal tube opening. Then esophagus balloon pressure sensor and flow sensor were connected with Bicore CP-100 pulmonary monitor. Dynamic intrinsic positive end-expiratory pressure (PEEPi, dyn), difference of esophagus pressure (dPes), work of breathing patient (WOBp), work of breathing ventilator (WOBv), pressure time product (PTP), tidal volume (Vt), respiratory rate (RR), minute ventilation (MV), peak inspiratory flow rate (PIFR), peak expiratory flow rate (PEFR), expiratory airway resistance (Rawe), fraction of inspiration (Ti/Ttot) and so on were measured. PEEPi,dyn was measured by esophagus balloon technique. Electrocardiogram and noninvasive blood pressure modes were added to HP M1165A monitor. Heart rate (HR) and blood pressure (BP) were also measured. Arterial blood was analyzed to measure pH, partial pressure of oxygen in arterial blood (PaO(2)), partial pressure of carbon dioxide in arterial blood (PaCO(2)) and saturation of arterial blood oxygen (SaO(2)). At first, PEEPi, dyn was measured when PEEPe was zero, which was called PEEPi, dynz and was set as baseline. Then PEEPe was set randomly, which was 0%, 40%, 60%, 80% and 100% of PEEPi, dynz respectively. Other parameters remained stable. All the indexes were measured 30 minutes after the level of PEEPe was changed. RESULTS: WOBp decreased as PEEPe increased, from (1.08 +/- 0.49) J/L of PEEPe-0% of PEEPi,dynz to (0.57 +/- 0.32) J/L of PEEPe-100% of PEEPi, dynz, and significant difference was found between each level of PEEPe and the baseline (P < 0.01). But we didn't find significant difference between PEEPe-80% of PEEPi,dynz and PEEPe-100% of PEEPi, dynz. WOBv increased significantly as PEEPe increased, from (1.50 +/- 0.47) J/L of PEEPe-0% of PEEPi, dynz to (1.82 +/- 0.56) J/L of PEEPe-80% of PEEPi, dynz and (1.85 +/- 0.48) J/L of PEEPe-100% of PEEPi,dynz(P < 0.01). The total WOB (WOBp + WOBv) remained steady. PTP trended to decrease, from (153.6 +/- 76.8) cm H(2)O x s x m(-1) of PEEPe-0% of PEEPi, dynz to (86.9 +/- 45.9) cm H(2)O x s x m(-1) of PEEPe-100% of PEEPi, dynz; the difference of PTP between PEEPe-40% of PEEPi,dynz and PEEPe-0% of PEEPi, dynz was significant(P < 0.05), the differences between other levels of PEEPe and PEEPe-0% of PEEPi, dynz were very significant (P < 0.01), but no significant difference was found between PEEPe-80% of PEEPi, dynz and PEEPe-100% of PEEPi, dynz. PEEPi,dyn also decreased significantly as PEEPe increased, from (7.70 +/- 1.42) cm H(2)O of PEEPe-0% of PEEPi, dynz to (2.10 +/- 0.57) cm H(2)O of PEEPe-100% of PEEPi, dynz, very significant differences were found between each level of PEEPe and the baseline (P < 0.01). Significant positive linear correlation was found between DeltaWOBp and DeltaPEEPi, dyn were(r = 0.609, P < 0.01, n = 10). dPes decreased as PEEPe increased, from (15.20 +/- 4.16) cm H(2)O of PEEPe-0% of PEEPi, dynz to (8.20 +/- 4.13) cm H(2)O of PEEPe-100% of PEEPi, dynz, and very significant differences were found between each level of PEEPe and the baseline (P < 0.01). But the difference between PEEPe-80% of PEEPi, dynz and PEEPe-100% of PEEPi, dynz wasn't significant, even dPes of PEEPe-100% of PEEPi, dynz was higher than that of PEEPe-80% of PEEPi, dynz. Vt didn't change markedly. RR, MV and f/Vt increased slightly. Both PIFR and PEFR didn't change markedly. At the same time, HR, BP and blood gas analysis were investigated, but no significant change was found. CONCLUSION: PEEPe can reduce WOBp significantly and improve the coordination between the patient and ventilator. It is shown that decrement of pressure difference between alveolar and central airway leads to decrement of WOBp.

Aged↗
PubMed2001

[A multicenter clinical study on clinical effects of meglumine cyclic adenylate in treating patients with chronic pulmonary heart disease].

OBJECTIVE: To observe the clinical effects of meglumine cyclic adenylate (MCA) in treating patients with chronic pulmonary heart disease. METHODS: 785 patients with chronic pulmonary heart disease were divided into two groups: MCA group and control group. Both groups of patients were treated with the same ordinary methods, but MCA was given in the MCA group. The period of treatment was 5-7 days. The degree of improvement in clinical symptoms, signs, ECG, pulmonary ventilation function and arterial blood gas analysis of the two groups before and after treatment were compared. RESULTS: The rates of improvement in clinical symptoms and signs were 92.2% and 73.6% in MCA group and control group respectively. VC increased (426 +/- 123) ml and (313 +/- 145) ml respectively as compared with the values before the treatment. FEV(1) increased (134 +/- 54) ml and (95 +/- 55) ml, PEF increased (0.78 +/- 0.32) L/s and (0.47 +/- 0.32) L/s and PaO(2) increased (23.4 +/- 9.5) mm Hg and (17.3 +/- 10.4) mm Hg respectively. The rates of ECG improvement were 63.7% and 41.2% respectively. There was significant difference between the two groups (P < 0.01 and 0.05). CONCLUSION: Significant therapeutic effects were obtained in treating patients of chronic pulmonary heart disease with respiratory and cardiac failure by using ordinary treatment measures combined with MCA injection.

Aged↗
PubMed2001

Kinetics of complexing activation by the magnesium ion on green crab (Scylla serrata) alkaline phosphatase.

As with mammalian enzymes, green crab (Scylla serrata) alkaline phosphatase can be activated by Mg2+ through a time-dependent course. The activation is mainly a Vmax effect. Tsou's method was used to study the kinetic course of activation. The results show that the enzyme was activated by a complexing scheme that had not been previously identified: the enzyme first reversibly and quickly binds Mg2+ and then undergoes a slow reversible course to activation, with a relatively high activation energy (78 +/- 4 kJ/mol) and a slow conformational change. The activation reaction is a single molecule reaction, and the apparent activation rate constant is independent of Mg2+ concentration if the concentration is sufficiently high. The microscopic rate constants of activation and the association constant were determined from the measurements. The proposed scheme may also be applied to the Mg2+ activation mechanism for mammalian enzyme, to explain why the activation rate is time-dependent and not diffusion controlled. Substrate binding was also shown to affect the activation rate constant.

Alkaline Phosphatase↗
PubMed2001

[Effect of inverse ratio ventilation on hemodynamics and oxygen metabolism in sheep with acute respiratory distress syndrome].

OBJECTIVE: To observe the effect of inverse ratio ventilation (IRV) on hemodynamics and oxygen metabolism in sheep with acute respiratory distress syndrome (ARDS). METHODS: Twelve ARDS sheep induced by LPS were admitted to this study, and received mechanical ventilation with volume controlled (VC) and pressure controlled ventilation (PC) (conventional ratio and inverse ratio) at the same level of total positive end expiratory pressure (PEEPt), data of hemodynamics and oxygen metabolism were collected at 30 min after the onset of each mode. RESULTS: With PC, peak airway pressure was lower than that with VC, but mean airway pressure was higher with IRV. At the same level of PEEPt, there was no difference in hemodynamics and oxygen metabolism between VC and VC-IRV, same as PC and PC-IRV. But compared with VC, arterial oxygen pressure and arterial oxygen saturation with PC-IRV were lower significantly (P < 0.05). CONCLUSION: PEEPt was a very important factor to improve oxygenation, short-term IRV was not better than VC or PC.

Acute Disease↗
PubMed2001

[Damage and economic threshold of the third generation of cotton bollworm in the Yangtze River basin cotton region of Jiangsu Province].

The impact of the third generation of cotton bollworm Helicoverpa armigera on shedding of buds and bolls and on bolling was studied by inoculating its larvae to cotton plants. The results showed that the shed rate of buds and bolls damaged by the larvae had the greatest impact on bolling, and its direct path coefficient was up to -0.8917. The larval population density and the number of buds and bolls damaged by the larvae impacted bolling mainly through the damaged shed rate during inoculating stage, and their indirect path coefficients were -0.8894 and -0.891 respectively. Both of the direct and indirect path coefficients of natural shed rate during inoculating stage to bolling were small, which showed that the cotton had little capacity of compensation while the third generation cotton bollworm occurring. The investigations of damage number by larvae showed that the damage equivalent of the 1st-6th instar larval were 0.02, 0.14, 0.31, 0.47, 0.84 and 1.54 old bolls respectively. Based on direct and indirect benefits from controlling, the economic threshold of the third generation of the bollworm was worked out to be 26 accumulated eggs per 100 plants.

Agriculture↗
PubMed2001

[Poison effect of plant granules on Oncomelania hupensis].

Plant granules (phi 2-3 mm) made of starch, gelatin and medicine plant powder were used to kill Oncomelania hupensis. The results showed that after eating the plant granules, the mortality of the snail was 92.5%-100% within 24 hrs. The poison effect of the plant granules was much better than that of others, e.g., they could kill snails 12-24 h earlier than Niclosamidum (1 x 10(-3) g.L-1). In a field experiment, the snail mortality was up to 61.5% by using plant granules.

Animals↗
PubMed2001

[Ameliorative effects of adrenomedullin on rat cardiac sarcoplasmic reticulum injured by isoproterenol].

Five indices were used to assess the degree of the ameliorative effects of adrenomedullin (Adm) in isoproterenol (ISO) induced injury of cardiac sarcoplasmic reticulum (SR) of rats: +/- LV dp/dtmax, SR Ca2+ uptake, Ca2+ release (in nmol/mg SR protein) and Ca(2+)-ATPase activity. Adm (5 x 10(-5) mol/L) was perfused into rat heart before cardiac function +/- LV dp/dtmax was determined. Cardiac SR was purified and SR Ca2+ uptake, Ca2+ release, Ca(2+)-ATPase activity, and 3H-ryanodine maximal binding (Bmax) were measured. After perfusion of Adm (5 x 10(-5) mol/L), the +LV dp/dtmax and -LV dp/dtmax in ISO injured heart were increased by 16.9% (2,135 +/- 281 vs 1980 +/- 302, P < 0.05) and 29.2% (1375 +/- 267 vs 1064 +/- 355, P < 0.05), respectively. Cardiac SR Ca2+ uptake and Ca2+ release were increased by 23.0% (15.0 +/- 1.4 vs 12.2 +/- 1.2, P < 0.01) and 43.5% (6.6 +/- 1.0 vs 4.6 +/- 0.6, P < 0.01), respectively. Ca(2+)-ATPase activity and 3H-ryanodine binding were increased by 23.0% (P < 0.01) and 42.2% (P < 0.05), respectively. It seems that Adm exerted a protective effect on cardiac function in injured rat heart by enhancing SR Ca2+ uptake and release, suggesting that Adm may play a therapeutic role in myocardial injury.

Adenosine Triphosphatases↗
PubMed2001

Early changes of arginine vasopressin and angiotensin II in patients with acute cerebral injury.

OBJECTIVE: To study the changes and clinical significance of arginine vasopressin (AVP) and angiotensin II (AT-II) in patients with acute moderate and severe cerebral injury. METHODS: The early plasma concentration was checked by radioimmunoassay in 47 cases of acute moderate and severe cerebral injury, 30 cases of non-cerebral injury and 30 healthy volunteers. RESULTS: The early plasma concentrations of AVP (50.23 ng/L +/- 15.31 ng/L) and AT-II (248.18 ng/L +/- 82.47 ng/L) in cerebral injury group were higher than those in non-cerebral injury group (AVP for 30.91 ng/L +/- 11.48 ng/L and AT-II for 120.67 ng/L +/- 42.49 ng/L, P<0.01). The early plasma concentrations of AVP and AT-II in cerebral injury group were also obviously higher than those of the volunteers (AVP for 5.16 ng/L +/- 4.23 ng/L and AT-II for 43.11 ng/L +/- 16.39 ng /L, P<0.001). At the same time, the early plasma level of AVP (58.90 ng/L +/- 18.12 ng/L) and AT-II (292.13 ng/L +/- 101.17 ng/ L) was higher in severe cerebral injured patients than moderate cerebral injured ones (AVP for 36.68 ng/L +/- 12.16 ng/L and AT-II for 201.42 ng/L +/- 66.10 ng/L, P<0.01). The early level of AVP and AT-II was negatively related to the GCS scales in acute cerebral injury. The early plasma concentrations of AVP (45.98 ng/L +/- 13.48 ng/L) and AT-II (263. 28 ng/L +/- 80.23 ng/L) were lower in epidural hematoma group than those of subdural hematoma and cerebral injury group (AVP for 64.12 ng/L +/- 15.56 ng /L and AT-II for 319.82 ng/L +/- 108.11 ng/L, P<0. 01). CONCLUSIONS: AVP and AT-II may play an important role in pathophysiologic process in the secondary cerebral injury. The more severe the cerebral injury is, the higher the early level of AVP and AT-II will be. The early plasma level of AVP and AT-II may be one of the severity indexes of cerebral injury.

Acute Disease↗
PubMed2001

Mental models and logical reasoning problems in the GRE.

The Graduate Record Examination (GRE) contains a class of complex reasoning tests known as logical reasoning problems. These problems are demanding for human reasoners and beyond the competence of any existing computer program. This article applies the mental model theory of reasoning to the analysis of these problems. It predicts 3 main causes of difficulty, which were corroborated by the results of 4 experiments: the nature of the logical task (Experiment 1), the set of foils (Experiment 2), and the nature of the conclusions (Experiments 3 and 4). This article shows how these factors can be applied to the design of new problems.

Educational Measurement↗