Factors Associated with Increased or Decreased Stress Level in French Children during the First COVID-19 Lockdown

In spring 2020, governments of many countries implemented lockdown measures to prevent the spread of the COVID-19 pandemic. Worldwide, the pandemic forced about 1.5 billion children to stay at home for several weeks and to experience homeschooling. The objective of this study was to assess the variation in stress levels and associated factors in school-aged children in France during the first COVID-19 lockdown. A cross-sectional study using an online questionnaire was designed by an interdisciplinary team involving hospital child psychiatrists and school doctors. Between 15 June and 15 July 2020, Educational Academy of Lyon (France) invited the parents of school-aged children to participate in this survey. The first part of the questionnaire concerned the children with data on lockdown conditions, socio-demographic data, daily rhythms (eating and sleeping), perceived stress variations, and feelings. The second part assessed parental perspectives on their child's psychological state and use of the mental health care system. Multivariate logistic regression was performed to identify factors associated with stress variation (increased or decreased). A total of 7218 questionnaires were fully completed by children from elementary school to high school with a balanced sex ratio. In summary, 29% of children reported a higher stress level during the lockdown, 34% reported a lower stress level, and 37% reported no stress variation in the usual situation prior to COVID-19. Parents were most often able to identify signs of increased stress levels in their children. The most influential factors in the variation of stress for children were academic pressure, family relationships, and fear of being infected or infecting a family member with SARS-CoV-2. Our study underlines the high impact of school attendance stressors on children in usual conditions and encourages vigilance for children whose stress levels have decreased during the lockdown but who may have increased difficulty re-exposing themselves upon deconfinement.

Clinical effectiveness of the Du Pont aca measurement of creatine kinase MB in serum from patients in a coronary-care unit

We evaluated the clinical effectiveness of measuring creatine kinase (CK; EC 2.7.3.2) isoenzyme MB and lactate dehydrogenase (LD; EC 1.1.1.27) isoenzymes in diagnosis of acute myocardial infarction. We used an agarose electrophoresis method to measure CK and LD isoenzymes and the Du Pont aca column method to measure CK-MB. Serial blood specimens were drawn from 100 patients consecutively admitted to our Coronary Care Unit. Because of the low diagnostic specificity for CK-MB measurements by both agarose electrophoresis and the discrete-analysis method, as compared with reported values, we re-evaluated our isoenzyme data by using Receiver Operating Characteristic curves. Such analysis of the data established optimal decision levels of greater than or equal to 25 U/L and greater than or equal to 18 U/L plus greater than or equal to 6% of total CK for serum CK-MB measured by the agarose electrophoresis and the aca methods, respectively, and an optimal decision level of greater than or equal to 0.92 for the ratio of LD 1/2 measured after agarose electrophoresis. At these decision levels we obtained a sensitivity of 100%, 100%, and 95% and a specificity of 94%, 92%, and 90% for CK-MB (agarose electrophoresis), CK-MB (aca), and the LD 1/2 ratio, respectively.

Clinical effectiveness of the Du Pont aca measurement of creatine kinase MB in serum from patients in a coronary-care unit

We evaluated the clinical effectiveness of measuring creatine kinase (CK; EC 2.7.3.2) isoenzyme MB and lactate dehydrogenase (LD; EC 1.1.1.27) isoenzymes in diagnosis of acute myocardial infarction. We used an agarose electrophoresis method to measure CK and LD isoenzymes and the Du Pont aca column method to measure CK-MB. Serial blood specimens were drawn from 100 patients consecutively admitted to our Coronary Care Unit. Because of the low diagnostic specificity for CK-MB measurements by both agarose electrophoresis and the discrete-analysis method, as compared with reported values, we re-evaluated our isoenzyme data by using Receiver Operating Characteristic curves. Such analysis of the data established optimal decision levels of greater than or equal to 25 U/L and greater than or equal to 18 U/L plus greater than or equal to 6% of total CK for serum CK-MB measured by the agarose electrophoresis and the aca methods, respectively, and an optimal decision level of greater than or equal to 0.92 for the ratio of LD 1/2 measured after agarose electrophoresis. At these decision levels we obtained a sensitivity of 100%, 100%, and 95% and a specificity of 94%, 92%, and 90% for CK-MB (agarose electrophoresis), CK-MB (aca), and the LD 1/2 ratio, respectively.

Observations on the heat stability and electrophoretic pattern of alkaline phosphatases extracted from various tissues

Various tissues were extracted with either normal saline or heat inactivated serum (HIS) and the heat stability and electrophoretic migration of the alkaline phosphatase enzymes (AP) of the extracts were compared to the heat stability and electrophoretic properties of serum AP. The electrophoretic pattern of HIS extracts of liver and bone differed from that of saline extracts but the pattern was unaffected if HIS was added to the saline extracts. The heat stabilities of the tissue AP also differed depending on whether they were extracted with saline or HIS. However, serum AP heat stability can help differentiate between liver and bone disease. It is concluded that the comparison of serum and tissue AP heat stabilities or the comparison of serum and tissue AP electrophoretic patterns as criteria for identification of the tissue source of the serum enzyme may be misleading since both these parameters vary, depending on the medium used for extracting the tissue and the extract(s) may contain a mixture of enzymes different from that in serum. It is further concluded from the electrophoretic studies on tissue AP that the increased serum AP in patients with hepatobiliary disease was unlikely to be due to regurgitation of bile but due to increased synthesis and release of alpha 1 and alpha 2 AP isoenzymes from liver, bile ducts or gall bladder. In patients with bone disease the increased serum AP is derived from bone. The source of the serum AP of "normal" subjects may be either liver or vascular tissue or both.

Effectof dialysis on tissue and serum alkaline phosphatase heat stability

Tissue extracts and serum samples were dialyzed against TRIS buffer and the heat stability of the alkaline phosphatase (AP) was examined before and after dialysis for various periods of time. The effect of adding a mixture of ions or heat inactivated polled serum (HIS) to the dialyzed samples was also investigated. Dialysis of tissue extracts or of serum resulted in an increase in the mean AP heat stability. Addition of the ion mixture to dialyzed bone or liver extracts decreased the AP heat stability. Addition of HIS to these extracts decreased the AP heat stability of dialyzed bone extract but had little effect on dialyzed liver extract. These results are discussed.