艾滋病流行态势与预防现状分析

从艾滋病流行态势的趋向,提出对高危人群的行为干预,并提出相应的预防措施,如健康教育、哨点监测、宽容策略、加强计划生育等.     

医学生循证医学知识、态度、行为和技能的调查分析

目的了解高年级医学本科生的循证医学知识、态度、行为和技能(KABP)的现况。方法整群抽样,横断面调查。结果对北京大学医学部285名高年级医学本科生的KABP情况调查结果显示,目前大部分高年级医学生对循证医学不了解,多数医学生在临床实践中不具备自我学习的主动性,循证医学知识运用情况和检索医学专业信息的技能水平较低。调查显示,专业是影响KABP的主要因素。结论大部分高年级医学本科生循证医学知识的掌握程度、临床实践行为、知识运用技能和信息检索技能均处于较低的水平,开展系统、有效的循证医学教育势在必行。     

Reporting presence or absence of named objects by a language-trained dolphin

Referential “reporting” was defined as the transmission of information about the presence or absence of symbolically-referenced real-world objects. In Experiment 1 two bottlenosed dolphins (Tursiops truncatus), trained in earlier studies to carry out instructions conveyed by imperative sentences expressed in artificial gestural or acoustic languages, each gave spontaneous indications that an object referenced in an imperative was absent from their tank. In Experiment 2 the dolphin tutored in the gestural language was taught to make explicit reports of object absence by pressing a “No” paddle in response to imperatives referencing an absent object. Absence was reported correctly on 84% of 97 missing-object probes inserted at random intervals among 598 sentences referring to objects that were present. Reports were typically made after active search of the tank for an average of 15.0 sec. False reports, that objects present were absent, were few (7.5%). In Experiment 3, the dolphin was taught an interrogative sentence form that enabled us to ask direct questions about the presence or absence of specific objects. Responses by the dolphin on the No paddle indicated absence, while responses on a “Yes” paddle indicated presence. From one to three objects were shown the dolphin and then placed in the tank in a discrete-trial procedure. In response to the interrogative, reports of object presence or absence were better than 91% correct with a single object in the tank and either that object or some other object referenced; accuracy declined to 72–78% correct with three objects present, but was still well above chance. Several lines of evidence suggested that the dolphin was attempting to remember which objects it had been shown, rather than conducting an active environmental search as in Experiment 2. The memory strategy became less efficient as the number of objects to be remembered increased. Overall, the results evidenced the language-trained dolphin's understanding of references to present or absent objects, its ability to inventory its environment to seek information about those objects, and its ability to report its obtained knowledge to others.     

Duodenal "diverticulization" for duodenal and pancreatic injury

Duodenal “diverticulization” has been achieved in thirty-four cases of combined duodenal and pancreatic or severe duodenal or pancreatic injury. The operation consists of gastric antrectomy with end to side gastrojejunostomy, tube duodenostomy, closure of the duodenal perforation, and drainage. The combined mortality for these thirty-four cases and a previously reported series of sixteen cases is 16 per cent. Regional complications that developed after duodenal diverticulization were generally well tolerated and not lethal. All duodenal and pancreatic fistulas closed spontaneously.     

Paroxysmal nocturnal hemoglobinuria associated with hepatic and portal venous thrombosis

Paroxysmal nocturnal hemoglobinuria is a form of chronic hemolytic anemia characterized by an intracorpuscular red cell defect which makes it highly susceptible to acid hemolysis, especially at night, and one of whose major complications and causes of death is spontaneous venous thrombosis. The disease and two cases in which portal hypertension secondary to the thrombotic phenomenon occurred are discussed. The surgical therapy for decompression of the portal bed by portal-azygos disconnection in one of these cases is presented and discussed.     

The use of stroma-free hemoglobin solution for partial exchange transfusion in aortic resection in dogs

Vascular surgery involves multiple transfusions with their concomitant hazards. At the start of each vascular procedure, 20 per cent of each patient's blood (approximately 1,000 of 5,600 ml) is removed and replaced with colloid and crystalloid and the withdrawn blood returned at the end of surgery. Theoretically, if 40 per cent of the blood volume (2,000+ ml) could be withdrawn, essentially no banked blood would be required for a major vascular procedure. Therefore, 40 per cent (900+ ml) of the blood volume of twenty greyhounds was withdrawn under anesthesia and replaced with stroma-free hemoglobin solution (SFHS). Abdominal aortic resection and graft replacement was performed, and any blood lost during the procedure was replaced with SFHS. After surgery the withdrawn blood was returned to the dog and excess volume removed with postoperative hemodilution diuresis. The study included a battery of twenty tests for monitoring during the procedure and at intervals from this project that in greyhounds 40 per cent or more of the blood volume may be removed and replaced with SFHS and major vascular surgery done without undue risk and with unaltered kidney function.     

Neurotoxic esterase in rooster testis

Neurotoxic esterase (NTE) is the putative target protein in the nervous system for the initiation of organophosphorus-induced delayed neuropathy. Here it is reported that NTE activity is present in rooster testis. Complete titration of rooster testis phenyl valerate esterases with paraoxon shows that about 15% of the enzymic activity is resistant to paraoxon. NTE activity after complete mipafox titration accounts for 30% of paraoxon-resistant phenyl valerate esterases and corresponds to 7.93 +/- 0.39 nmol/min/mg of protein (mean +/- SD, n = 7). Testis NTE is inhibited in vitro similarly to brain NTE by several organophosphorus compounds. Subcellular fractionation studies of the testis indicate that most NTE activity is particle bound. Testis NTE is also inhibited in vivo by several organophosphorus esters but to a lesser extent than brain NTE. Birds doses with organophosphorus compounds, causing delayed neuropathy, became grossly ataxic, but no testicular pathology was noted by light microscopy in roosters killed 15 days after administration. Serum testosterone levels also measured 15 days after dosing were not different from those of a control group. Recovery of NTE activity was faster in testis than in brain (4 days vs 6 days to recover to 50% of initial activity) in animals that received a high dose of an organophosphorus ester which cause delayed neuropathy.     

Concentrations of lead in the soft tissues of male rats during a long-term dietary exposure

Newborn rats of albino Wistar strain were exposed to lead from birth, first indirectly through maternal milk and then directly through a diet containing 0.5% lead acetate. At 3, 6, and 12 months of age some of the male rats were killed for the determination of the concentrations of lead in the blood, brain, kidneys, and liver. This long-term exposure resulted in a slight retardation of growth, yet no change in the food consumption was seen. Concentrations of lead in the blood and brain were similar at 3 and 6 months of age, but significantly higher at 12 months, while the concentrations of lead in the kidneys increased significantly with age. Of the brain parts examined the forebrain had the highest concentration of lead, which increased significantly with age. The present study, together with already published data, demonstrated clearly that lead accumulated in rat brain during the suckling period remains relatively unchanged throughout adult life, while the concentrations in the blood and other soft tissues fall rapidly after weaning. Thus the blood lead level cannot be used as a measure of the amount of lead in the brain, particularly in the case of long-term or intermittent exposure of the young.