Statistical methods of unmeasured confounder control based on negative control theory / 中华流行病学杂志

Controlling unmeasured confounders in non-randomized controlled studies is challenging. Negative control theory is based on the theoretical concept that the test result of negative controls must be negative. Setting appropriate negative control incorporates the specificity of association into population studies for the identification and control of unmeasured confounders. This paper explains the principles to control unmeasured confounders using negative control theory from a statistical perspective. A detailed introduction of derived methods based on negative control theory is also introduced, including adjusted standardized mortality ratio method, calibrating P-value method, generalized difference-in-difference model and double negative control method. The reasonable application of those derived methods is also comprehensively summarized based on representative case studies. Negative control is an important statistical design to identify, revise and control unmeasured confounders and a valuable method for comparative effectiveness research based on real-world data.

The history, current situation and sanitary management countermeasures of dual piping water supply in Shanghai / 上海预防医学

Objective To fully understand the history, current situation and major health-related problems of dual piping water supply, and to investigate the sanitary situation of the dual piping water supply system in Shanghai. Methods 10 suppliers and 35 employees, as well as 175 apartment owners were investigated by data collecting, field survey, and individual interview. Results The development of dual piping water supply industry in Shanghai slowed down gradually since 2008, and nearly stagnated at present.Only 30%-50%of households choose dual piping water supply on average.Talents shortage and payment in arrears were the major obstructions to the development of the industry.Most users considered dual piping water supply as one of the reasons of apartment purchase, while some apartment owners did not use it because they used water purifiers as substitute or they believed that tap water quality was good enough.Qualification rate of both health inspection and water quality were above 95%.Due to design deficiency and low utilization of water supply network, the quality of back water and tap water of dual piping water supply was worse than the quality of water directly taken from the water processing equipment, both differences were significant(P<0.05). Conclusion There is still certain demands in the market of dual piping water supply.However, there are hidden sanitary dangers in the industry due to its stagnant development and low enthusiasm of operators and lack of governance.Therefore, it is suggested that governance should be clarified, new operational method should be explored and inspection mechanism including social engagement should be built to ensure the sanitation and safety of dual piping water supply .

Analysis on the clinical characteristics and related risk factors of patients with hemorrhagic transformation after cerebral infarction / 中华流行病学杂志

Objective To analyze and summarize the clinical characteristics and risk factors for patients with hemorrhagic transformation (HT) after cerebral infarction to provide guidance for its clinical treatment and prevention.Methods In this study,data from 49 hospitalized patients with HT in the First Department of Neurology,China-Japan Union Hospital of Jilin University from October 2009 to March 2012,were reviewed retrospectively and 106 cases with acute cerebral infarction only during the same period,were chosen randomly as controls.Gender and age of the patients were comparable.Relevant information was collected.SPSS 17.0 statistical package was applied for data processing.Qualitative data were processed with x2 test,and measurable data was processed with t-test.Each index was analyzed with uni-variate analysis while statistically significant risk factors were included in the logistic review model to conduct the multivariate regression analysis.Results (1) Clinical symptoms deteriorating after hemorrhage in 21 cases accounted for 42.9％ of the HT group,among which the cases on degree of disturbance to consciousness had an aggravation in 8 cases and hemiplegia increase in another 7 cases.Headaches and dizziness were found in 5 cases.(2)Number of infarction within 15 days after the occurrence of HT accounted for 87.0％.(3)HT-related factors increased the risk of HT in cerebral infarction such as cortical infarction,large area of infarction,atrial fibrillation,cerebral embolism,diabetes and high level of low-density lipoprotein cholesterol (P＜0.05).The most important factors were atrial fibrillation and cerebral embolism.(4)PH-2 seemed more unlikely to link with clinical symptoms than other subtypes of HT.Conclusion Cerebral infarction after occlusion of the main artery trunk was prone to HT,especially when it appeared within 15 days.Short-term prognosis seemed to be related to the subtypes of HT,with risk factors as cortical infarct,massive cerebral infarction,atrial fibrillation,cerebral embolism,diabetes,high low-density lipoprotein cholesterol etc.on HT.

Mechanisms of autologous chondrocytes mass transplantation in the repair of cartilage defects of rabbits' knee / 中国骨伤

<p><b>OBJECTIVE</b>To trace the pathological changes of the cultured autologous chondrocytes mass after implanted in cartilage defects and investigate the pathophysiological mechanisms of the antologous chondrocytes mass transplantation in the repair of cartilage defects.</p><p><b>METHODS</b>Twenty-four New Zealand white rabbits of 4 to 6 month-old and weighing more than 3.0 kg (female and male was unrestricted) were randomly divided into experiment group and the control group. For 12 rabbits of experiment group, the cartilage defects were repaired with the autologous chondrocytes mass and sealed with one piece of periosteum. Firstly, cartilage tissue of 10 to 30 mg was obtained from the shoulder of the rabbits after anaesthetized by 1 mg/kg 20% sumianxin. Then, chondrocytes were isolated from the cartilage tissue with 0.2% type II collagenase digestion and were cultured in DMEM/F-12 supplemented with 20% fetal bovine serum (FBS), 50 microg/ml ascorbic acid-2-phosphate, 0.4 mM proline, 5 microg/ml insulin and 1 mM non-essential amino acids (NEAA) in flasks in vitro. The cells were harvested until a thin film of the cells covered the bottom of the flask could be seen with naked eyes. Then the film was collected with a curled glass stick and formed a solid mass. On this time, the animal was anaesthetized again and the full-thickness cartilage square defect of 4.0 mm x 6.0 mm was fabricated in the patellar grove of distal femur, and then the cellular mass was transplanted into the defect covered by one piece of periosteum which obtained from the upper anterior of tibia and sealed with the femoral condyles. For 12 rabbits of the control group, the defects were sealed with one piece of periosteum only. The animals were sacrificed in the 1st, 3rd, 6th and 12th weeks after the operation respectively. The histologic sections were stained with safranin O-fast green, hematoxylin-eosin (H&E) and picric acid-Sirius red and immunostained for type II collagen and aggrecan.</p><p><b>RESULTS</b>In the 1st week, the transplanted cells oriented to articular surface differentiated to matured hyaline chondrocytes and excrete large amount cartilage matrix. In the 3rd week, the trend was more obvious and the periosteum was union to the cell mass. In the 12th week, the defects were repaired with hyaline-like cartilage tissue, and in the 24th week, the repair tissue turned to matured hyaline cartilage. In the control group, the defects were repaired with fibrocartilage tissues.</p><p><b>CONCLUSION</b>It was evidenced that the defects were repaired by the autologous chondrocytes mass transplantation. The procedure was gradual and initialed from up toward joint to down to the deep of the defect.</p>

Clinical observation of fengbei huayu recipe in treating diabetic nephropathy / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To study the effects of Fengbei Huayu recipe (FHR) on urinary albumin excretion rate (UAER) in patients with diabetic nephropathy (DN).</p><p><b>METHODS</b>Seventy-two type 2 DN patients in III or IV stage were randomly divided into two groups, 36 in each group. All patients were treated with conventional hypoglycemic agents and hypotensor, but those in the treated group were given additionally with FHR twice a day for 8 successive weeks. The changes of UAER, D-polymer, glycosylate hemoglobin (HbA1c), renal function indexes, including blood urea nitrogen (BUN) and serum creatinine (SCr), and blood lipids, including total cholesterol (TC) and triglyceride (TG) in the two groups before and after treatment were compared.</p><p><b>RESULTS</b>The levels of UAER, D-polymer, HbA1c, TC and TG were significantly decreased after treatment in the treat- ed group (P < 0.05), and the improvement were superior to those in the control group (P <0.05) respectively. But the difference of renal function before and after treatment showed no significance in both groups.</p><p><b>CONCLUSION</b>FHR could not only obviously decrease the level of UAER, but also decrease the levels of blood glucose and blood-lipids in patients with DN.</p>

The association of HLA-DRB1 allele polymorphism with the genetic susceptibility to liver cirrhosis due to hepatitis B virus / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the association of human leucocyte antigen (HLA)-DRB1 allele with the genetic susceptibility to cirrhosis due to hepatitis B virus(HBV).</p><p><b>METHODS</b>One hundred and six patients with cirrhosis due to HBV in Hubei area were investigated for HLA-DRB1 gene by polymerase chain reaction-sequence specific primers technique. The results were compared with those from 108 normal healthy people.</p><p><b>RESULTS</b>The frequency of HLA-DRB1*1201/1202 allele was 20.28% in patient group, which was significantly higher than the frequency (6.01%) in control group, the relative risk (RR) being 4.9878 (P<0.01). The frequency of HLA-DRB1*1501/1502 allele was decreased in patient group (patient 6.6%, control 16.67%, RR=0.3043, P<0.05), while the frequencies of other HLA-DRB1 alleles were not significantly different(P>0.05).</p><p><b>CONCLUSION</b>HLA-DRB1*1201/1202 allele may be the susceptibility gene in patients with cirrhosis due to HBV in Hubei Han nationality; HLA-DRB1*1501/1502 allele is a resistant gene in patients with cirrhosis.</p>