Mathematical and computer modeling of acute normovolemic hemodilution

BACKGROUND: Advocates of acute normovolemic hemodilution (ANH) frequently neglect to consider the decreasing hematocrit of the patient during both hemodilution and the subsequent operative procedure and the need to begin transfusion at some minimal hematocrit. STUDY DESIGN AND METHODS: For more accurate prediction of the efficacy of ANH, equations were derived and a computer model developed that allowed accounting for the decreasing hematocrit due to blood loss in an isovolemic patient and calculating the red cell volume on a minute-by-minute basis; the model also began the transfusion of ANH blood on a mL-for-mL basis when the minimal hematocrit was reached and transfused any remaining blood following completion of the case. The red cell volume saved by performing ANH for a given estimated blood volume (EBV) was expressed as either the fraction of the red cell volume of a routinely banked unit of blood (red cells stored in additive solution: volume 350 mL, hematocrit 0.65) or the number of units saved. RESULTS: The number of units saved in a typical example–EBV, 5000 mL; pre-ANH hematocrit, 0.40; minimal hematocrit at which transfusion was begun, 0.25 over a range of estimated blood losses (500-2500 mL); and 1 to 5 ANH units drawn–never exceeded 0.6. Even with extensive hemodilution, as in a child (EBV, 1500 mL; pre-ANH hematocrit, 0.40; minimal hematocrit at which transfusion was begun, 0.15; 5 units drawn; and estimated blood losses, 2500, 1500, and 1000 mL) with a postdilution hematocrit of 0.16, the savings would have been only 0.29, 0.44, and 0.49 units, respectively. CONCLUSION: Because of the decreasing hematocrit in a bleeding isovolemic patient and the need to begin transfusion at some minimal hematocrit, the theoretic savings in red cell volume attributable to ANH is less than had previously been appreciated, and additional ANH does not necessarily result in additional patient benefit.     

Transgenic mice expressing human sickle hemoglobin are partially resistant to rodent malaria

The polymorphic frequency of the gene for beta s-globin involved in the generation of sickle trait and sickle cell anemia in the human population is caused by the enhanced resistance of sickle trait individuals to Plasmodium falciparum malaria, as supported by epidemiologic and in vitro studies. However, the mechanism for the protective effect of sickle hemoglobin in vivo has not been fully defined. The generation of transgenic mice expressing high levels of human beta s- and alpha-chains has allowed us to study this phenomenon in vivo in an experimental model. We infected the transgenic beta s mice with two species of rodent malaria and found a diminished and delayed increase in parasitemia as compared with controls. This is in contrast to our previous studies involving the introduction of a beta A transgene, which does not alter the infection. The use of this model allowed us to address the question of the mechanism of protection against malaria in mice expressing sickle hemoglobin. We find that splenectomy of transgenic mice completely reverses the protection against Plasmodium chabaudi adami infection. The results reported have shown a relationship between the presence of the beta s gene product and partial resistance to malaria in an experimental model in vivo and shows that the spleen plays an important role in this protection.     

Computer administration of a school-based adolescent health survey

Objective : To examine the utility of notebook computers in the collection of data in large scale surveys.
Methodology : A notebook computer administered survey of health in adolescents was conducted in 1992 using a multi-instrument questionnaire. Students in school years 7,9 and 11 in private and government schools in Melbourne and rural Victoria participated.
Results : Parental consent was obtained with an 83% response rate. Each student answered questions directly onto the computer taking an average of 68 min to complete the highly branched confidential but not anonymous questionnaire. Students were presented with on average 33% of the 897 possible questions. Over 90% of students reported enjoying using the computer. Those who reported answering the questions honestly all the time ranged from 68 to 85%, increasing with grade level.
Conclusions : The use of computers in survey research provides many advantages in data collection including exposure only to relevant questions and the opportunity of asking sensitive questions.     

磁共振检查患者负性情绪的预防和疏导

MR设备磁体孔径狭长,扫描间相对封闭,加之扫描时间较长,梯度噪声较大,以及快速交变梯度场引起的生物效应,使患者产生了不同程度的心理压力和恐惧,即医学上称之幽闭恐惧症。在人们日益对健康关注的今天,如何消除患者这种负性情绪,以获得满意的检查效果,值得我们更进一步的探讨。1患者检查前的心理特点分析初检的患者,依其年龄、性格、文化修养及病情轻重多存在有担心、恐惧,尤其担心检查结果。由于长期以来人们对“核磁共振”的错误理解所产生的“核”畏惧,担心作此项检查会给自己身体带来辐射损害,另外担心检查的结果。大多数患者到医院来就诊大都存在身心不适,希望能查明自己不适的病因;但有部分患者担心花了高昂的检查费用,检查未发现异常,进而对医院产生不信任;另有一部分患者担心查出自己身患癌症,此类患者心理活动极其复杂。而对那些再次磁共振检查或多次检查的患者,更多的担心是自己病情的好转情况,或者是对设备噪声的恐惧。2检查前的磁共振知识宣讲、解释和交流沟通针对不同患者不同的心理特点,检查前通过对磁共振知识的宣讲,让患者从心理上消除对“核”辐射的恐惧;纠正患者对医院的偏见和误解,耐心解释患者提出的关于病情、费用、检查的不良作用等问题,与患者建立...     

跨专业团队合作式自我管理教育对体检高血压患者的干预效果研究

目的 探讨跨专业团队合作式自我管理教育在体检高血压患者干预中的应用效果。方法 选取2019年4—6月在武汉某三级综合性教学医院的100名体检的高血压患者为研究对象,实施跨专业团队合作式自我管理教育。分别在干预前、干预3个月末、干预6个月末评估患者低密度脂蛋白胆固醇控制达标率、高血压治疗态度与信念评分、高血压治疗依从性评分、血压控制达标率。结果 干预前、干预3个月末、干预6个月末高血压患者低密度脂蛋白胆固醇及血压控制达标率比较差异具有统计学意义（P<0.001）。干预前、干预3个月末、干预6个月末高血压患者坚持治疗态度与信念、服药治疗态度与信念、治疗性生活方式态度与信念、持续治疗困扰与顾虑得分比较差异有统计学意义（P<0.001）。干预前、干预3个月末、干预6个月末高血压患者遵医服药行为、不良服药行为、日常生活管理行为、烟酒嗜好管理行为得分比较差异有统计学意义（P<0.001）。结论 跨专业团队合作式自我管理教育对体检高血压患者进行健康管理,可提高患者治疗的态度与信念及治疗依从性,从而提高患者血压及低密度脂蛋白胆固醇控制达标率。     

Atypical reactions associated with use of angiotensin-converting enzyme inhibitors and apheresis

BACKGROUND: Anaphylactic or atypical reactions, characterized by flushing, hypotension, dyspnea, and bradycardia, have been reported in patients undergoing hemodialysis, low-density lipoprotein apheresis, IgG affinity column apheresis, therapeutic plasma exchange, and desensitization immunotherapy while receiving angiotensin-converting enzyme (ACE) inhibitor therapy. STUDY DESIGN AND METHODS: Records were reviewed of 299 consecutive patients undergoing therapeutic plasma exchange with colloid replacement at the University of North Carolina Hospitals from September 1981 through December 1993. Charts were selected for further analysis if atypical reactions (flushing or hypotension defined as a mean decrease in blood pressure of 20 torr or greater) occurred during apheresis or if there was concurrent administration of an ACE inhibitor. RESULTS: Fourteen (4.7%) of 299 patients were receiving ACE inhibitor therapy at the time of apheresis; all 14 experienced an atypical reaction. In contrast, 20 (7%) of 285 patients not receiving ACE inhibitors developed atypical reactions (p < 0.001). The 14 ACE inhibitor patients accounted for 41 percent (14/34) of all patients having atypical reactions during apheresis. CONCLUSION: Patients receiving ACE inhibitor therapy who are undergoing therapeutic plasma exchange with albumin replacement solutions are at high risk (100%) for atypical reactions. It is recommended that ACE inhibitors be withheld for at least 24 hours before that procedure.     

Urinary nuclear magnetic resonance spectroscopy of a Bangladeshi cohort with hepatitis-B hepatocellular carcinoma: A biomarker corroboration study

AIM: To establish if a distinct urinary metabolic profile could be identified in Bangladeshi hepatitis-B hepatocellular carcinoma(HCC) patients compared to cirrhosis patients and controls. METHODS: Urine samples from 42 Bangladeshi patients with HCC(39 patients with hepatitis-B HCC), 47 with cirrhosis on a background of hepatitis B, 46 with chronic hepatitis B, and seven ethnically-matched healthy controls were analyzed using nuclear magnetic resonance(NMR) spectroscopy. A full dietary and medication history was recorded for each subject. The urinary NMR data were analyzed using principal component analysis(PCA) and orthogonal partial leastsquared discriminant analysis(OPLS-DA) techniques. Differences in relative signal levels of the most discriminatory metabolites identified by PCA and OPLSDA were compared between subject groups using an independent samples Kruskal-Wallis one-way analysis of variance(ANOVA) test with all pairwise multiple comparisons. Within the patient subgroups, the MannWhitney U test was used to compare metabolite levels depending on hepatitis B e-antigen(HBe Ag) status and treatment with anti-viral therapy. A BenjaminiHochberg adjustment was applied to acquire the level of significance for multiple testing, with a declared level of statistical significance of P 0.05.RESULTS: There were significant differences in age(P 0.001), weight(P 0.001), and body mass index(P 0.001) across the four clinical subgroups. Serum alanine aminotransferase(ALT) was significantly higher in the HCC group compared to controls(P 0.001); serum α-fetoprotein was generally markedly elevated in HCC compared to controls; and serum creatinine levels were significantly reduced in the HCC group compared to the cirrhosis group(P = 0.004). A threefactor PCA scores plot showed clustering of the urinary NMR spectra from the four subgroups. Metabolites that contributed to the discrimination between the subgroups included acetate, creatine, creatinine, dimethyamine(DMA), formate, glycine, hippurate, and trimethylamine-N-oxide(TMAO). A comparison of relative metabolite levels confirmed that carnitine was significantly increased in HCC; and creatinine, hippurate, and TMAO were significantly reduced in HCC compared to the other subgroups. HBe Ag negative patients showed a significant increase in creatinine(P = 0.001) compared to HBe Ag positive patients in the chronic hepatitis B subgroup, whilst HBe Ag negative patients showed a significant decrease in DMA(P = 0.004) in the cirrhosis subgroup compared to HBe Ag positive patients. There were no differences in metabolite levels in HCC patients who did or did not receive antiviral treatment. CONCLUSION: Urinary NMR changes in Bangladeshi HCC were identified, corroborating previous findings from Egypt and West Africa. These findings could form the basis for the development of a cost-effective HCC dipstick screening test.     

MTHRF基因C677T多态性与ALL患儿MTX血药浓度和毒副反应的相关性

【目的】探讨亚甲基四氢叶酸还原酶（MTHFR）C677T基因多态性对急性淋巴细胞白血病（ALL）儿童甲氨蝶呤（MTX）血药浓度和毒副反应的影响。【方法】筛选50例采用大剂量MTX治疗的ALL患儿,采用多聚酶链反应一限制性内切酶片段多态性分析法（PCR-RFLP）检测MTHFRC677T多态性,应用荧光偏振免疫分析法（FPIA）24h、48h、72h监测患儿外周血中甲氨蝶呤动态血药浓度,记录相关毒副反应。【结果】24h时、48hMTX血药浓度均以突变型纯舍子（TT）最高（均P〈0．05）,突变型杂合子（CT）次元;MTHFRC677T基因型与肝损害、消化道反应和骨髓抑制相关,携带T突变基因患儿（CT＋TT组）发生肝损害的风险是野生型纯合子（CC）的5．12倍（95％CI：1．372～19．077）,发生3～4级消化道反应的风险是CC型的4．41倍（95％CI：1．066～18．266）,3～4级骨髓抑制发生率依次为TT型、CT型和CC型（均P〈0．05）。【结论】MTHFRC677T基因多态性影响ALL患儿大剂量MTX化疗期间MTX血药浓度,与肝损害、消化道反应和骨髓抑制等毒副反应相关。