ABSTRACT
Objective@#To evaluate the role of tuberculin skin test prified protein derivative (PPD) in defining the screening scope of close contacts of tuberculosis cases in disposal of tuberculosis outbreak in schools.@*Methods@#In a senior middle school in August 2019, 1 553 students of the grade two were tested by PPD because of a school tuberculosis outbreak. PPD results were compared to grade one students without any association with this tuberculosis epidemic, who were also tested by PPD when beginning school. Potential association between PPD distribution characteristics and tuberculosis case distribution were analyzed.@*Results@#Twenty nine grade two students were diagnozed as tuberculosis infection, seven of which were PPD positive, and with the same MIRU-VNTR genotype. In grade one, 0.1 % (1/796) student showed strong PPD positive, 34.3% (273/796) student showed positive. For grade two students, significant higher rate of strong PPD positive [5.9% (45/757)], and PPD positive [52.0% (394/757)] were observed ( χ 2=45.71, 49.90, P <0.01). Proportion of strong PPD positive in the first floor of the teaching building ( 19.4 %), where tuberculosis cases clustered, was significantly higher than that in other floors ( χ 2=89.81, P <0.01); Number of strong PPD positive students increased with TB cases in each floor of the teaching building ( r =0.99, P <0.01). Proportion of strong PPD positive and PPD positive in floors of the dormitory, where TB cases lived, was significantly higher than in other floors ( χ 2=49.4, 64.9 , P <0.01). Number of strong PPD positive and PPD positive students increased with TB cases in each floor of the teaching building ( r =0.84, 0.56, P <0.01).@*Conclusion@#Strong PPD positive rate well reflects tuberculosis infection of close contacts, and is recommended for defining the scope of screening.
ABSTRACT
Objective@#To elucidate the association between large conductance calcium-activated potassium channels (BKCa) in the paraventricular hypothalamic nucleus (PVN) and sympathetic outflow in rats with chronic heart failure (CHF) .@*Methods@#Male Wistar rats (6-7 weeks old) were randomized to sham operated group and CHF group (coronary artery ligation) . Two weeks after operation, BKCa inhibitor Iberiotoxin (IBTX) was infused into PVN by osmotic minipumps, rats were divided into following groups: sham+aCSF, CHF+aCSF, sham+low dose IBTX (0.125 nmol/nl) , CHF+low dose IBTX, sham+moderate dose IBTX (1.25 nmol/nl) , CHF+moderate dose IBTX, sham+ high dose IBTX (12.5 nmol/nl) , and CHF+high dose IBTX (n=6 each) . Additional rats were grouped as follows: sham+vehicle, sham+KCNMB4 knockdown (by rAAV2-KCNMB4 shRNA virus injection in PVN) , CHF+vehicle, CHF+ KCNMB4 knockdown group (n=6 each) . The cardiac function was determined by echocardiography, left ventricular hemodynamics were measured invasively, renal sympathetic nerve activity (RSNA) was recorded at 6 weeks after coronary artery ligation or sham operation. The contents of norepinephrine (NE) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) in plasma were determined by enzyme-linked immunosorbent assay. The protein and mRNA expression of KCNMB4 in PVN were measured by immunofluorescence staining, Western blot, and real-time PCR, mRNA expression of BKCa in PVN was detected by real-time PCR.@*Results@#Compared with the sham operation group, the cardiac function of the heart failure group was significantly reduced (P<0.05) , and the plasma NE and the serum NT-proBNP were significantly elevated (P<0.05) . The protein and mRNA expression of KCNMB4 in PVN were obviously down-regulated in CHF rats (P<0.05) . After perfusion of IBTX or KCNMB4 knockdown by microinjection of rAAV2-KCNMB4 shRNA virus,right ventricular weight/body weight and lung weight/body weight ratio as well as left ventricular end-diastolic diameter were increased and left ventricular ejection fraction was decreased (all P<0.05) , the sympathetic driving indexes was increased in sham rats, changes of these parameters further aggravated in CHF rats (P<0.05) . KCNMB4 knockdown further downregulated protein expression in PVN of CHF rats.@*Conclusion@#Downregulation and blunted function of BKCa in PVN may contribute to sympathoexcitation and deterioration of cardiac function in rats with chronic heart failure.