第七章《排泄》章节的教学中学生能力的培养

素质教育的今天,教师应追随每一堂课,对培养学生的素质能力上下硬功夫.为此,在生物第二册第七章<排泄>的教学中深有感触.阐述如下:

Effect of Fouling on Feeding, Oxygen Consumption and Waste Excretion of Pearl Oyster Pinctada martensii in Daya Bay Cultivation

Biofouling is a particular problem in the pearl oyster culture. It may reduce the growth and survival rates of the cultured species. Foulers are often themselves filter feeders, and are therefore potential competitors for food resource with the cultured species. Fouling organisms may also reduce the oxygen supply. A study was conducted to measure the impact of foulers on feeding oxygen consumption, and waste excretion. POM, ammonia, phosphate and oxygen concentration were measured in various treatments （cultured species, foulers）. This study showed that fouling organisms had significant effect on food uptake, oxygen consumption and waste excretion. The clearance rate, ammonia and phosphate release rate, oxygen consumption rate of the fouled pearl oyster were greater than those of the clean pearl oysters. Other foulers that settled on cages or buoys also contributed much to phytoplankton depletion, oxygen consumption and concentration increase of ammonia and phosphate in water. Therefore, this study showed us that foulers were important competitors in the pearl oyster cultivation of Daya Bay in November 2005.

关于计算机辅助教学的思考

随着信息时代、知识经济向我们走来,计算机辅助教学已崭露头角,业内不少人士已经开始了对计算机辅助教学(CAI)的探索和使用,在此,我们也谈一谈有关看法。 一、CAI走进课堂是现代教学的必然趋势 随着我国教育事业的不断发展和完善,素质教育已在全国范围内得到提倡和推广。

Tissue distribution,excretion and pharmacokinetics of R-hap in rats

The purpose of this study is to characterize the tissue distribution, excretion and pharmacokinetics profiles of R-hap in healthy Wistar rats. R-hap was radiolabeled by the IODO-GEN method. Tissue distribution and urinary, fecal and biliary excretion patterns of ^125I-R-hap were investigated following a single i.v. bolus injection. Pharmacokinetics properties of ^125I-R-hap were also examined after a single i.v. bolus injection. The trichloroacetic acid （TCA） precipitated radioactivity was widely distributed and rapiclly diminished in most tissues. Kidney contained the highest radioactivity among all organs and the distribution of ^125I-R-hap to fat was minimal. The cumulative excretion of ^125I-R-hap reached 71.81% ± 2.15% of the administered radioactivity at 48 h and 94.71% ± 1.50% at 120 h. Urinary excretion was the dominant route of elimination following i.v. administration, as 80.64% ± 1.47% and 14.07% ± 0.95% of administered radioactivity were recovered in urine and feces, respectively, in intact rats over 120 h. The mean areas under the plasma concentration-time curve was （8818.4 ± 576.1） Bq/h/mL. The results of tissue distribution, excretion and pharmacokinetics of R-hap in rats provided biopharmaceutical basis for the design of future clinical trials.

Nitrate Leaching in an Irrigated Wheat-Maize Rotation Field in the North China Plain

Soil water deep drainage and nitrate (NO-3) leaching losses below the root zone were investigated in a 1 ha wheat-maize rotation field under traditional agricultural management that local farmers generally follow in the North China Plain, using the soil water balance method and NO3-N concentration in suction samples. Water drainage, and NO3-N distribution and leaching losses exhibited pronounced spatial and temporal variability. Soil water deep drainage and NO3-N leaching loss mostly occurred during the sum…

Research on Volume Identification with the Method of Discharging at the Velocity of Sound

The method of volume identification in pneumatics was studied through theoretical analysis and experimental investigation. Regarding discharging from a container as a thermodynamic process with invariable index the dependence of the container’s volume on the pressure in the container and the index, during discharging at the velocity of sound, is deduced. Then through a lot of experiments, the value of index n of the process is found with a given precision and a specified volume range. Furthermore, the feasibility and practicability of this method are verified by experiments.

Diagnosis and management of colonic injuries following blunt trauma

AIM: To retrospectively evaluate the preoperative diagnostic approaches and management of colonic injuries following blunt abdominal trauma. METHODS: A total of 82 patients with colonic injuries caused by blunt trauma between January 1992 and December 2005 were enrolled. Data were collected on clinical presentation, investigations, diagnostic methods, associated injuries, and operative management. Colonic injury-related mortality and abdominal complications were analyzed. RESULTS: Colonic injuries were caused mainly by motor vehicle accidents. Of the 82 patients, 58 (70.3%) had other associated injuries. Laparotomy was performed within 6 h after injury in 69 cases (84.1%), laparoscopy in 3 because of haemodynamic instability. The most commonly injured site was located in the transverse colon. The mean colon injury scale score was 2.8. The degree of faecal contamination was classified as mild in 18 (22.0%), moderate in 42 (51.2%), severe in 14 (17.1%), and unknown in 8 (9.8%) cases. Sixty-seven patients (81.7%) were treated with primary repair or resection and anastomosis. Faecal stream diversion was performed in 15 cases (18.3%). The overall mortality rate was 6.1%. The incidence of colonic injury- related abdominal complications was 20.7%. The only independent predictor of complications was the degree of peritoneal faecal contamination (P = 0.02). CONCLUSION: Colonic injuries following blunt trauma are especially important because of the severity and complexity of associated injuries. A thorough physical examination and a combination of tests can be used to evaluate the indications for laparotomy. One stage management at the time of initial exploration is mostoften used for colonic injuries.

Laparoscopic cystogastrostomy for the treatment of pancreatic pseudocysts: A case report

Pancreatic pseudocysts （PPs） are collections of pancreatic secretions that are lined by fibrous tissues and may contain necrotic debris or blood. The interventions including percutaneous, endoscopic or surgical approaches are based on the size, location, symptoms and complications of a pseudocyst. With the availability of advanced imaging systems and cameras, better hemostatic equipments and excellent laparoscopic techniques, most pseudocysts can be found and managed by laparoscopy. We describe a case of a 30-year-old male patient with a pancreatic pseudocyst amenable to laparoscopic cystogastrostomy. An incision was made through the anterior gastric wall to expose the posterior gastric wall in close contact with the pseudocyst using an ultrasonically activated scalpel. Then, another incision was made for cystogastrostomy to obtain complete and unobstructed drainage. The patient recovered well after operation and was symptom-free during a 6-mo follow-up, suggesting that laparoscopic cystogastrostomy is a safe and effective alternative to open cystogastrostomy for minimally invasive management of PPs.

Effect of atrial natriuretic peptide on ischemia-reperfusion injury in a porcine total hepatic vascular exclusion model

AIM： To evaluate the effect of ANP on warm I/R injury in a porcine THVE model.METHODS： Miniature pigs （mini-pigs） weighing 16-24 kg were observed for 120 min after reperfusion following 120 min of THVE. The animals were divided into two groups. ANP （0.1 μg/kg per min） was administered to the ANP group （n = 7）, and vehicle was administered to the control group （n = 7）. Either vehicle or ANP was intravenously administered from 30 min before the THVE to the end of the experiment. Arterial blood was collected to measure AST, LDH, and TNF-α. Hepatic tissue blood flow （HTBF） was also measured. Liver specimens were harvested for p38 MAPK analysis and histological study. Those results were compared between the two groups.RESULTS： The AST and LDH levels were lower in the ANP group than in the control group; the AST levels were significantly different between the two groups （60 min： 568.7 ± 113.3 vs 321.6 ± 60.1, P = 0.038 〈 0.05, 120 rain： 673.6± 148.2 vs 281.1±44.8, P = 0.004 〈 0.01）. No significant difference was observed in the TNF-α levels between the two groups. HTBF was higher in the ANP group, but the difference was not significant. A significantly higher level of phosphorylated p38 MAPK was observed in the ANP group compared to the control group （0min： 2.92± 1.1 vs 6.38 ±1.1,,P= 0.011 〈 0.05）.Histological tissue damage was milder in the ANP group than in the control group.CONCLUSION： Our results show that ANP has a protective role in I/R injury with p38 MAPK activation in a porcine THVE model.

Carbon Budget of Bastard Halibut Paralichthys Olivaceus in Relation to Body Weight and Temperature

The effects of body weight and temperature on the carbon budget of the juvenile bastard halibut,Paralichthys olivaceus, were studied at temperature 13.5, 18, 21.5 and 24 ℃, respectively. The carbon intake, faecal and growth carbon were measured, and the carbon respiration was calculated using the carbon budget equation (C C=G C+F C+R C). The combined relationship between different components of the carbon budget, body weight and temperature could be described by regression equations:C C=1.0206W 0.8126e 0.1483T; G C=0.0042W 1.4096 (-5.11T3+285.90T2-5173.72T+30314.03);F C=0.0485W 0.7711e 0.1624T U C = 1.4333W 0.6715e 0.1487T. Body weight had no significant effect on the carbon absorption efficiency and the conversion efficiency.

Increased N-terminal pro-brain natriuretic peptide level predicts atrial fibrillation after surgery for esophageal carcinoma

AIM: To evaluate the value of plasma N-terminal pro- brain natriuretic peptide (NT-proBNP) level for predicting postoperative atrial fibrillation (AF) in patients undergoing surgery for esophageal carcinoma. METHODS: NT-proBNP levels were measured in 142 patients 24 h before and 1 h after surgery for esophageal carcinoma. All patients having a preoperative cardiac diagnosis by electrocardiogram (ECG), remained under continuous monitoring for at least 48 h after surgery, and then underwent clinical cardiac evaluation until discharge. RESULTS: Postoperative AF occurred in 11 patients (7.7%). AF patients were significantly older (69.6 ± 12.2 years vs 63.4 ± 13.3 years, P = 0.031) than non-AF patients. There were no significant differences in history of diabetes mellitus, sex distribution, surgical approach, anastomosis site, intraoperative hypotension and postoperative fever. The preoperative plasma NT-proBNP level was significantly higher in patients who developed postoperative AF (121.3 ± 18.3 pg/mL vs 396.1 ± 42.6 pg/mL, P = 0.016). After adjustment for age, gender, chronic obstructive pulmonary disease (COPD), history of cardiac diseases, hypertension, postoperative hypoxia and thoracic-gastric dilation, NT-proBNP levels were found to be associated with the highest risk factor for postoperative AF (odds ratio = 4.711, 95% CI = 1.212 to 7.644, P = 0.008).CONCLUSION: An elevated perioperative plasma BNP level is a strong and independent predictor of postoperative AF in patients undergoing surgery for esophageal carcinoma. This finding has important implications for identifying patients at higher risk of postoperative AF who should be considered for preventive antiarrhythmic therapy.

Secretion of melatonin and 6-sulfatoxymelatonin urinary excretion in functional dyspepsia

To evaluate blood concentration of melatonin and urinary excretion of its metabolite, 6-sulfatoxymelatonin （6-OHMS）, in functional dyspepsia （FD）. METHODS： Ninety individuals were enrolled in the study： 30 in each study group： patients with postprandial distress syndrome （PDS）, epigastric pain syndrome （EPS）, and controls. Blood samples were drawn at 02：00 and 09：00 h and 24-h urine collection was performed. Serum melatonin and urinary 6-OHMS concentrations were measured by enzyme-linked immunosorbent assay. RESULTS： Serum melatonin concentration at night and in the morning was significantly （P 〈 0.001） higher inPDS patients [at 02：00 h-93.3 pg/mL, quartile range （QR）： 79.8-116.2; at 09.00 h-14.3 pg/mL, QR： 7.06-19.0] than in EPS （57.2 pg/mL, QR： 42.6-73.1, 8.1 pg/mL, QR： 4.2-9.3） and control patients （57.7 pg/mL, QR： 51.2-62.5; 8.1 pg/mL, QR： 5.4-10.3）. A similar relationship was observed for urinary 6-OHMS excretion. Patients with severe PDS symptoms had a higher melatonin concentration than these with moderate syndromes, whereas patients with severe EPS had a lower urinary 6-OHMS excretion than patients with moderate symptoms.CONCLUSION： Evaluation of melatonin serum concentrations and 24-h urinary 6-OHMS excretion are useful methods for differential diagnosis of various clinical forms of FD.

Assessment of duodenal circular drainage in treatment of superior mesenteric artery syndrome

AIM： To assess the clinical value of duodenal circular drainage for superior mesenteric artery syndrome （SMAS）. METHODS： Forty-seven cases of SMAS were treated with duodenal circular drainage from 1959 to 2001. Clinical data were analyzed retrospectively. RESULTS： In this group, good effects were achieved in 39 cases treated with duodenal circular drainage after 2-15 years of follow-up. The other eight cases were first treated with anterior repositioning of the duodenum （two cases）, duodenojejunostomy （five cases）, subtotal gastrectomy and billroth I gastrojejunostomy （one case）, but vomiting was not relieved until duodenal circular drainage was performed again. A follow-up study of 8-10 years revealed satisfactory results in these eight patients. CONCLUSION： In SMAS, if the reversed peristalsis is strong and continuous, and vomiting occurs frequently, the symptom can not be relieved even if the obstruction of duodenum is removed surgically. The key treatment is the relief of reversed peristalsis. The duodenal circular drainage can resolve the drainage direction of duodenal content, thus relieving the symptom of vomiting.

IMPACT OF STARVATION ON SURVIVAL, MEAT CONDITION AND METABOLISM OF CHLAMYS FARRERI

The effects of 60 day starvation on survival rate, condition index (CI), changes of nutrient composition of different tissues, respiration and excretion of scallop Chlamys farreri were studied in laboratory from Oct. 17 to Dec. 15,1997. Two groups (control and starvation with 200 individuals each) were cultured in two 2 m 3 tanks, with 31 to 32 salinity water at 17℃. Starvation effects were measured after 10, 20, 40 and 60 days. There was no mass mortality of scallops of the two tanks and survival rates of the control and starvation groups were 93.5% and 92.0%, respectively. Starvation had strong effect on the meat condition of the scallops, especially after 10 days; when relative lipid percentage dropped sharply while relative protein percentage increased. The impact of starvation on the oxygen consumption rate (OCR) and the ammonia N excretion rate (AER) was obvious. The OCR increased rapidly after 10 days but decreased after 20 days. The AER increased after 10 days and 20 days, but decreased obviously from 20 to 40 days. The O:N ratios varied to different degrees, and minimized after 20 days. The low O:N ratios implied that the protein was the main material for the metabolism of C. farreri.

Excretion of biliary compounds during intrauterine life

In adults,the hepatobiliary system,together with the kidney,constitute the main routes for the elimination of several endogenous and xenobiotic compounds into bile and urine,respectively.However,during intrauterine life the biliary route of excretion for cholephilic compounds,such as bile acids and biliary pigments,is very poor.Although very early in pregnancy the fetal liver produces bile acids,bilirubin and biliverdin,these compounds cannot be efficiently eliminated by the fetal hepatobiliary system,owing to the immaturity of the excretory machinery in the fetal liver.Therefore,the potentially harmful accumulation of cholephilic compounds in the fetus is prevented by their elimination across the placenta.Owing to the presence of detoxifying enzymes and specifi c transport systems at different locations of the placental barrier,such as the endothe-lial cells of chorionic vessels and trophoblast cells,this organ plays an important role in the hepatobiliary-like function during intrauterine life.The relevance of this excretory function in normal fetal physiology is evident in situations where high concentrations of biliary compounds are accumulated in the mother.This may result in oxidative stress and apoptosis,mainly in the placenta and fetal liver,which might affect normal fetal development and challenge the fate of the pregnancy.The present article reviews current knowledge of the mechanisms underlying the hepatobiliary function of the fetal-placental unit and the repercussions of several pathological conditions on this tandem.

Localization of ANP-synthesizing cells in rat stomach

AIM: To study the morphological positive expression of antrial natriuretic peptide (ANP)-synthesizing cells and ultrastructural localization and the relationship between ANP-synthesizing cells and microvessel density in the stomach of rats and to analyze the distribution of the three histologically distinct regions of ANP-synthesizing cells. METHODS: Using immunohistochemical techniques, we studied positive expression of ANP-synthesizing cells in rat stomach. A postembedding immunogold microscopy technique was used for ultrastructural localization of ANP-synthesizing cells. Microvessel density in the rat stomach was estimated using tannic acid-ferric chloride (TAFC) method staining. Distribution of ANP-synthesizing cells were studied in different regions of rat stomach histochemically. RESULTS: Positive expression of ANP-synthesizing cells were localized in the gastric mucosa of rats. Localization of ANP-synthesizing cells identified them to be enterochrochromaffin cells (EC) by using a postembedding immunogold electron microscopy technique. EC cells were in the basal third of the cardiac mucosa region. ANP-synthesizing cells existed in different regions of rat stomach and its density was largest in the gastric cardiac region, and the distribution order of ANP-synthesizing cells in density was cardiac region, pyloric region and fundic region in mucosa layer. We have also found a close relationship between ANP-synthesizing cells and microvessel density in gastric mucosa of rats using TAFC staining. CONCLUSION: ANP-synthesizing cells are expressedin the gastric mucosa. EC synthesize ANP. There is a close relationship between ANP-synthesizing cells and microvessel density in gastric mucosa of rats.The distribution density of ANP-synthesizing cells is largest in the gastric cardiac region.

Effects of the dietary supplementation with fructooligosaccharides on the excretion of nitrogen and phosphorus in Miichthys miiuy fries

Effects of dietary supplementation with fructooligosaccharides on the excretion of nitrogen and phosphorus in Miichthys miiuy fries were investigated. Nine hundred Miichthys miiuy fries were divided into 3 groups, each with triplicates. The basal diet and the basal diet supplemented with carnitine groups were considered as the negative and positive controls respectively. Results showed that the nitrogen concentration in excreted feces decreased significantly in fries fed the diet supplementation with 1000×10?6 fructooligosaccharides and 200×10?6 carnitine (P<0.05). The ammonic-nitrogen concentration decreased significantly in the carnitine group only (P<0.05), indicating the decreasing tendency caused by the supplementation with fructooligosaccha-rides. Supplementation with both did not have significant effects on the concentration of phosphorus in feces of Miichthys miiuy fries.

The presence of ANP in rat peritoneal mast cells

Atrial natriuretic peptide （ANP） is an important component of the natriuretic peptide system. A great role in many regulatory systems is played by mast cells. Meanwhile involvement of these cells in ANP activity is poorly studied. In this work, we have shown the presence of ANP in rat peritoneal mast cells. Pure fraction of mast cells was obtained by separation of rat peritoneal cells on a Percoll density gradient. By Westem blotting, two ANP-immunoreactive proteins of molecular masses of 2.5 kDa and 16.9 kDa were detected in lysates from these mast cells. Electron microscope immunogold labeling has revealed the presence of ANP-immunoreactive material in storage, secreting and released granules of mast cells. Our findings indicate the rat peritoneal mast cells to contain both ANP prohormone and ANP. These both peptides are located in mast cell secretory granules and released by mechanism of degranulation. It is discussed that many mast cell functions might be due to production of natriuretic peptides by these cells.

Colorectal and interval cancers of the Colorectal Cancer Screening Program in the Basque Country (Spain)

AIM To assess proportions, related conditions and survival of interval cancer(IC).METHODS The programme has a linkage with different clinical databases and cancer registers to allow suitable evaluation. This evaluation involves the detection of ICs after a negative faecal inmunochemical test(FIT), interval cancer FIT(IC-FIT) prior to a subsequent invitation, and the detection of ICs after a positive FIT and confirmatory diagnosis without colorectal cancer(CRC) detected and before the following recommended c o l o n o s c o p y, I C-c o l o n o s c o p y. W e c o n d u c t e d a retrospective observational study analyzing from January 2009 to December 2015 1193602 invited people onto the Programme(participation rate of 68.6%).RESULTS Two thousand five hundred and eighteen cancers were diagnosed through the programme, 18 cases of IC-colonoscopy were found before the recommended follow-up(43542 colonoscopies performed) and 186 IC-FIT were identified before the following invitation of the 769200 negative FITs. There was no statistically significant relation between the predictor variables of ICs with sex, age and deprivation index, but there was relation between location and stage. Additionally, it was observed that there was less risk when the location was distal rather than proximal(OR = 0.28, 95%CI: 0.20-0.40, P < 0.0001), with no statistical significance when the location was in the rectum as opposed to proximal. When comparing the screen-detected cancers(SCs) with ICs, significant differences in survival were found(P < 0.001); being the 5-years survival for SCs 91.6% and IC-FIT 77.8%.CONCLUSION These findings in a Population Based CRC Screening Programme indicate the need of population-based studies that continue analyzing related factors to improve their detection and reducing harm.