[A comparison of clinical characteristics between patients with and without"recurrence"RNA positive with COVID-19].

Objective: To analysis the clinical characteristics of"recurrence"RNA positive patients with Coronavirus disease 2019 （COVID-19） and compared with those without"recurrence". Methods: 98 patients with COVID-19 in Wuhan Jinyintan Hospital and designated treatment hospitals in Quanzhou were included in this study from February 2020 to April 2020. There were 55 males and 43 females， aged from15 to 83 years， with a median age of 57.5 years， in which 20 cases were complicated with basic diseases. 15 of these patients had been diagnosed and hospitalized had been found as"recurrence"2019-nCoV RNA positive after discharge while the other 83 cases were all negative. The clinical classification of all patients was common type. Clinical data of the COVID-19 RNA"recurrence"patients were collected， and general situations， symptoms， laboratory examinations and CT images were also observed and analyzed. The patients were divided into 2019-nCoV"recurrent"group and 2019-nCoV"non-recurrent"group. There are 10 males and 5 females in 2019-nCoV"recurrent"group while 45 males and 38 females in"non-recurrent"group （χ²=0.800，P=0.371）. The age of 2019-nCoV"recurrent"group （57±21） was higher than that of"non-recurrent"group（53±17）. 8 of 15 the COVID-19"recurrent"group patients and 12 of 83"non-recurrent"patients have basic diseases. IgG and IgM of 2019-nCoV， IL-6， procalcitonin， ESR， CRP， BNP and other serum biochemical index levels were measured and compared between groups. Results: （1） The proportion of patients with common type of COVID-19 was 15.3% during 2-week medical observation after discharge. （2） All of the 2019-nCoV"recurrent"patients were hospitalized due to COVID-19 RNA positive， when they were quarantined after discharged from hospital. All the patients with mild symptoms which were clarified as common type， including 5 cases of fever， 6 cases of cough， 5 cases of expectoration， and 2 cases of slight shortness of breath. The time of symptoms appeared on （5.73±2.82） days after discharge. （3） The serum procalcitonin of all 2019-nCoV"recurrent"group patients were normal（all<0.05 ng/ml）. The BNP of"recurrent"group （151±171） ng/L， was higher than that of"non-recurrent"group （63±78） ng/L （t = 3.207， P = 0.000）. There was no significant difference in laboratory tests like leukocyte ［（6.17±2.4） and （6.04±2.41）×109/L］， lymphocyte［（1.59±0.52） and （1.32±0.64）×109/L］， CRP ［（12.54±28.20） and （21.74±25.63）mg/L］， ESR ［（31.07±28.72） and （34.10±22.16）mm/1 h］， AST ［（24.73±9.15） and （30.24±23.20）U/L］， ALT ［（22.60±12.82） and （36.47±34.12）U/L）， LDH ［（268±208） and （270±164）U/L］， D-dimer ［（0.60±0.50） and （0.84±0.98）µg/L］， ferritin ［（294±195） and （395±319）µg/L］， IL-6 ［（9.17±6.42） and （14.28±17.74）ng/Lï¼½ and BUN （5.77±2.66） and （4.74±2.81）U/Lï¼½ between"recurrent"and"non-recurrent"groups （all P>0.05）. （4） In"recurrent"group， ground glass， exudative or solid lesions could be found in most of the chest CT performed on re-admission. Meanwhile， fibrosis lesion was relatively rare. （5） There were no secondary transmissions were found to be caused by the 2019-nCoV"recurrent"group patients. Conclusions: Most of the 2019-nCoV patients had underlying diseases and active lesions were still found in CT images， so the possibility of virus replication may still exist. All"recurrent"patients had mild illness which may suggest that they were in recovery stage, and no evidence of transmission is found.

The effect of cobalt-60 irradiation on the infectivity of Toxoplasma gondii.

Toxoplasma gondii cysts in the tissues of experimentally infected mice and pigs were irradiated with cobalt-60 at various doses and used to infect mice and kittens. Loss of parasite infectivity was confirmed following irradiation whereas control animals inoculated with non-irradiated infected tissues became infected. Experiments were repeated to calculate the minimal effective dose (MED) of irradiation to eradicate parasite infectivity. The MED for the Chinese NT strain and the American ME-49 and TS-2 strains of T. gondii cysts in mouse and pig tissues was approximately 0.6 kGy. The infectivity for mice of NT strain bradyzoites irradiated at a dose of 0.45 kGy was reduced 10,000-fold. Such irradiation may be valuable in practical operations to control T. gondii in pork products.

Downregulation of right ventricular phosphodiesterase PDE-3A mRNA and protein before the development of canine heart failure.

Phosphodiesterase III (PDE-3) inhibitors are inotropes used to treat congestive heart failure (HF). Previous studies showed PDE-3A mRNA levels were reduced in the left ventricle (LV) in dogs subjected to pacing-induced HF. The present study evaluated a time-course for RV-specific changes in PDE-3A mRNAs and proteins after pacing for 3 wk (n = 4) or in HF (4-5 wk; n = 4-6). Total RNA from LV/RV tissues was isolated for Northern analyses; cytosolic and microsomal proteins were prepared for PDE-3A immunoblots. PDE-3A mRNAs (7-8 and 10 kb) were normalized against glyceraldehyde-3-phosphodehydrogenase (GAPDH) or ribosomal 18s with similar results. PDE-3A/GAPDH ratios in 3 wk were unchanged in LV, but significantly (p < 0.05) reduced by 48% in RV vs unpaced controls (n = 8). In contrast, PDE-3A (7-8 kb)/GAPDH ratios were significantly reduced in HF by 50-59% in both ventricles. Consistent with mRNA levels, significant reductions in microsomal 135 kDa (93-96%) and cytosolic 120 kDa PDE-3A (57-69%) were seen in both ventricles in HF or in the RV at 3 wk; an LV-specific reduction (50%) in cytosolic 80 kDa PDE-3A in HF was also detected. In summary, RV-specific downregulation of PDE-3A mRNA/protein(s) at 3 wk suggests that hemodynamic rather than humoral mechanisms are responsible, and provides a molecular basis for the limited efficacy of milrinone in the progression of HF.

Immediate-early gene expression in human saphenous veins harvested during coronary artery bypass graft operations.

Saphenous vein graft occlusion is a common late complication of coronary bypass grafting. Intimal smooth muscle cell hyperplasia is a component of this pathobiology, but the underlying molecular events are poorly understood. Immediate-early genes are activated shortly after growth stimulation and subserve cellular functions, which may contribute to intimal smooth muscle cell accumulation. In the present study, human saphenous vein grafts were harvested with minimal manipulation during coronary bypass and processed for isolation of total ribonucleic acid to examine change in immediate-early gene expression of messenger ribonucleic acid by Northern blotting techniques. Thirty saphenous vein grafts were incubated at 4 degrees C in Dulbecco's modified Eagle media from 30 minutes to 10 hours. The messenger ribonucleic acids for immediate-early genes c-fos and c-myc were weak or undetectable in controls but were increased (> 10 times controls) within 1 hour (c-fos) and persisted for at least 6 hours (c-myc) after harvest. Our results demonstrate, for the first time in human vascular tissue, incipient immediate-early gene induction. This information may lead to molecular therapies to control saphenous vein graft disease.

Studies on the use of cobalt-60 irradiation to control infectivity of Toxoplasma gondii cysts.

Mouse brains harboring the Chinese NT strain of Toxoplasma gondii cysts were homogenized with normal saline and irradiated with cobalt-60 gamma rays at various doses. The homogenate was introduced intraperitoneally into NIH mice or per os into kittens. Loss of infectivity was confirmed according to the following criteria: no cyst found in mouse brain impression smears on the 50th day after inoculation; no oocyst found in feces of kittens 3-15 days after inoculation; subinoculation in mice and a negative IHA test. All bioassays, parasitological examinations and serological tests in the control group gave positive results. Activity of radioactive source: 10 KCi; uniform dosage: 1238 rad/min; dose range of irradiation: 0.1-1.0 KGy. Minimal effective dose of gamma rays to control infectivity of T. gondii cysts was 0.55 KGy. Infectivity of bradyzoites irradiated with gamma rays at a dose of 0.45 KGy decreased by 10,000 times. Minimal effective dose of gamma rays to control infectivity of American ME-49 and Ts-2 strain, is slightly higher (0.6KGy) than that of NT strain. These studies present useful data for practical use of cobalt-60 to control infectivity of T. gondii in meat products.

Development of decompensated dilated cardiomyopathy is associated with decreased gene expression and activity of the milrinone-sensitive cAMP phosphodiesterase PDE3A.

BACKGROUND: Phosphodiesterase III (PDE3) inhibitors are inotropic agents used to treat congestive heart failure (CHF) and are less effective in patients with severe CHF. Little is known about relative changes in PDE3 activity or gene expression during the evolution of cardiomyopathy. METHODS AND RESULTS: In the present study, we evaluated temporal changes in PDE3A gene expression before and after pacing-induced CHF in nine mongrel dogs. Three weeks of left ventricular (LV) pacing produced LV end-diastolic pressures of 15+/-1.7 mm Hg, whereas overt CHF at 4 to 5 weeks was associated with LV end-diastolic pressures of 24+/-1.7 mm Hg; prepacing values were 6.6+/-0.6 mm Hg. Total RNA isolated from LV tissues was analyzed on Northern blots; 10 unpaced normal hearts served as tissue controls. Signals for PDE3A mRNAs (7, 8, and 10 kb) or PDE4D (7.6 kb) were normalized against glyceraldehyde-3-phosphate dehydrogenase (GAPDH) or ribosomal 18S RNA. Before the onset of CHF, PDE3A/GAPDH ratios were not different between the control and 3-week paced groups. In contrast, all PDE3A/GAPDH ratios were selectively reduced by 52%, and PDE3A/18S was reduced by 70% (P<.05) in CHF; PDE4D/GAPDH (or 18S) was unchanged. LV tissues from four control and four CHF dogs were also processed to isolate cytosolic and microsomal membrane protein for cAMP PDE3 activity assays. CHF was associated with a significant 54% reduction (P<.05) in microsomal but not cytosolic PDE3 activity. CONCLUSIONS: Selective downregulation of PDE3A may account in part for the ineffectiveness of milrinone in the treatment of severe CHF.