病毒性心肌炎患儿肌钙蛋白I和T的检测及意义

目的：探讨心肌肌钙蛋白I和T在儿童病毒性心肌炎的诊断和预测预后的作用。方法：4l例心肌炎患儿在治疗前及治疗3周后测血清cTnI和cTnT。结果：心肌炎患儿治疗前血清cTnI和cTnT高于对照组，治疗3周后均有不同程度下降．伴心力衰竭者下降程度小。结论：血清cTnI和cTnT是心肌细胞损伤极敏感的指标．是诊断和预测心肌炎较好的指标。     

Reference values for cardiac troponins T and I in healthy neonates

OBJECTIVES: Cardiac troponins T (cTnT) and I (cTnI) are the most sensitive biochemical parameters in the detection of myocardial damage. In neonates, in utero exposure to tocolytic therapy results in detectable values of cardiac troponins after delivery. Additionally, some preliminary results suggest that the upper reference limits for healthy newborns are higher than those for adults but definitive reference limits for newborns are not available. Our objective was to determine those limits. DESIGN AND METHODS: In this study we investigated the distribution of cTnT and cTnI in cord blood of 869 healthy newborns. cTnT was determined with the 3rd generation assay and cTnI with the Dade Behring assay on a Dimension RxL. For data analysis Student's t test and the Mann-Whitney U test were used. RESULTS: Using the 99th percentile, the upper reference limit in healthy termed newborns was 0.097 microg/l for cTnT and 0.183 microg/l for cTnI. Compared to the adult values, the newborn upper limit was tripled for cTnT and doubled for cTnI. Statistically significant differences were found between males and females for cTnT and between natural childbirth and caesarean section for cTnI. CONCLUSION: Healthy-termed newborns have a higher upper reference limit for both cTnT and cTnI compared to adults. This circumstance must be taken into account when interpreting slightly "elevated" cTnT and cTnI values in newborns.     

Immune alterations in hemodialyzed patients. I. Effect of blood transfusion on T-lymphocyte subpopulations in hemodialyzed patients

The immune status in 42 patients with end-stage renal failure on maintenance hemodialysis was studied by using monoclonal antibodies to lymphocyte subpopulations. Lymphopenia, reductions in the proportion of OKT4+ cells and OKT4+/OKT8+ cell ratio were observed in hemodialyzed patients. These alterations in immune status were observed in 34 transfused patients, but not in 8 patients without history of blood transfusion. The proportion of OKT8+ cells was increased in patients with history of blood transfusion. When transfused patients were divided according to the dose of blood transfused in the last 2 yr, the most serious change was observed in those who received greater than 10 u of transfusion. The dose of blood transfused in the last 2 yr correlated positively with the proportion of OKT8+ cells (p less than 0.01) and inversely with OKT4+/OKT8+ cell ratio (p less than 0.05). The duration of hemodialysis did not affect the alterations in immunoregulatory cells. These results indicate that alterations in immune features in hemodialyzed patients may be linked to the history of blood transfusion rather than that of uremia and/or hemodialysis.     

Normal cardiac output in relation to age and body size.

The resting cardiac output was measured in 151 healthy persons (109 males and 42 females) of 4 to 78 years of age by the earpiece dye-dilution method by using an automatic calibration device of dye concentration. Cardiac index had a significantly inverse correlation to age in 105 cases with the age higher than 20 years: r=-0.491 and y=-4.874-0.023x, where y is cardiac index (liters/min/m2) and x is age (years). Stroke index also decreased linearly by aging throughout all ages: r=-0.426 and y=71.0-0.26 x, where x is stroke index (ml/m2) and x is age. There is no significant difference between males and females. A significant difference was found between the young group below 14 years of age and the other group older than 15 years when cardiac output was correlated to body sizes such as height, weight and surface area. The former which is corresponding to the growth age showed significantly higher cardiac output than the latter. From these results, age-matched normal predicted values were presented. It is suggested that the measured cardiac index and stroke index should be taken as abnormal if those values deviate from the normal value by 30% or more.     

Radionuclide studies in chronically hemodialyzed patients. Bone scintigraphy for the evaluation and control of renal osteopathy

The clinical applicability of bone scintigraphy (Tc99m MDP) was evaluated in 42 patients on maintenance hemodialysis. Typical scintigraphic findings are shown which were related to hormonal and biochemical parameters of calcium and phosphate metabolism. Visual grading of representative regions for metabolic bone disease in bone scans was compared to scintimetry which applies a bone to soft tissue ratio to grade osseous abnormalities. It could be shown that visual interpretation and grading of the findings according to a score is sufficient to assess the degree and extent of renal bone disease. Semiquantitative analysis of bone scintigrams by scintimetry did not improve the diagnostic information.     

Stability of cardiac troponins and CK-MB mass isoenzyme.

The stability of an analyte can have an important influence on its diagnostic performance and therefore should be documented before an analyte is introduced into routine practice. The stability of creatine kinase MB isoenzyme (CK-MB), troponin I and troponin T was studied by incubating samples at temperatures between 26 degrees C and 39 degrees C for periods up to 5400 min. Arrhenius plots were made which showed that all three proteins demonstrated a rapid decrease in stability between 15 degrees C and 20 degrees C. The activation energies for CK-MB, troponin I and troponin T were 7.7, 6.34 and 6.34 cal/mol, respectively.     

Comparison of cardiac troponin T and I in healthy men and in aortic valve replacement.

Troponins are of outstanding importance for the diagnosis of myocardial infarction. Cardiac troponin T (cTnT) and the various cardiac troponin I (cTnI) assays differ with respect to method comparison, diagnostic sensitivity and diagnostic specificity. To understand the differences in the diagnostic behavior of troponin assays, AccuTnI and Elecsys Troponin STAT were used in a group of healthy men and in the follow-up of patients with aortic valve replacement (AVR). Within the healthy subjects AccuTnI was able to differentiate two subgroups from each other, whereas the cTnT concentrations of all subjects were below the detection limit. In AVR patients, cTnT and cTnI correlated sufficiently, if the postoperative periods were taken into consideration. There was a rapid increase in cTnI within 24 h. In contrast, a broad peak was evident for cTnT between 48 and 120 h. The results emphasize more the differences in the release of cTnI and cTnT from the cytoplasm and the thin filaments of the cardiomyocytes than the modifications of the troponins circulating in the blood.     

Increase in blood plasma levels of boron and strontium in hemodialyzed patients

Boron and strontium concentrations in blood plasma of controls and hemodialyzed patients from two Centers were determined by inductively coupled plasma emission spectrometry. Boron concentrations in blood plasma were respectively, in controls 2.6 +/- 0.9 mumol/l and in hemodialyzed patients 16.1 +/- 5.6 mumol/l before the dialysis session and 9.5 +/- 3.2 mumol/l at the end. The decrease in blood plasma during the dialysis was concomitant with an increase in the dialysis fluid (1.2 +/- 0.7 mumol/l at the beginning and 4.6 +/- 1.8 mumol/l at the end). Strontium concentrations in blood plasma were respectively, in controls 0.22 +/- 0.06 mumol/l and in hemodialyzed patients 0.62 +/- 0.24 mumol/l before the dialysis session and 0.64 +/- 0.14 mumol/l at the end. The mean concentration of strontium in the dialysis fluid was the same before (0.49 +/- 0.11 mumol/l) and after the dialysis session (0.49 +/- 0.10 mumol/l), but a transfer between plasma and dialysis fluid was shown by individual changes. Some considerations about these results are put forward but their possible clinical consequences are not yet known.     

Reference values for cardiac troponins I and T in a goal-oriented concept of health: cardiac marker values in a series of outpatients without acute coronary syndromes

BACKGROUND: Cardiac troponins are part of the new definition of acute myocardial infarction (AMI) by the European Society of Cardiology and the American College of Cardiology (ESC/ACC). In the new guidelines, it was suggested to establish reference values for cardiac troponins to calculate the 0.99 quantile (Q99) as cutoff for AMI diagnosis. PATIENTS AND METHODS: We run a prospective series of troponin measurements in unselected outpatients who had no suspicion of cardiac ischemia. The selection of patients as reference population is based on a "goal-oriented concept of health". One hundred and ninety-five patients agreed that 10-ml additional blood was drawn at the occasion of the venous puncture done routinely in the evaluation of their case. Cardiac troponin I was measured using a point of care (POCT) device (Stratus CS, DadeBehring, TNI-PO). Additionally, heparin-plasma was obtained and immediately deep-frozen to -80 degrees C for later batch measurement of cardiac troponin T (Elecsys 2010, Roche Diagnostics, TnT) and troponin I (Centaur, Bayer, TnI-CL). RESULTS: The Q99 values were 0.14 microg/l for TnI-PO, 0.023 microg/l for TnT and 0.07 microg/l for TnI-CL in patients with creatinine levels below 1.5 mg/dl. These values lay above those obtained from people at good health for reference study purposes. On the level of our cutoffs, CVs were 7.5%, 6.4% and 23.7% for TnI-PO, TnT and TnI-CL, respectively. CONCLUSIONS: Only the TnI-PO and TnT tests fulfilled the imprecision criteria in our study. TnI-PO values between 0.10 and 0.14 microg/l and TnT values between 0.01 and 0.03 microg/l have to be interpreted carefully. Patients presenting with chest pain will be possibly true positives, but patients without chest pain and nondiagnostic ECGs should be subjected to repetitive troponin measurements and further noninvasive investigation and maybe not directly sent to the cardiac catheter laboratory.     

Cardiac troponins I and T are biological markers of left ventricular dysfunction in septic shock

BACKGROUND: Cardiac depression in severe sepsis and septic shock is characterized by left ventricular (LV) failure. To date, it is unclear whether clinically unrecognized myocardial cell injury accompanies, causes, or results from this decreased cardiac performance. We therefore studied the relationship between cardiac troponin I (cTnI) and T (cTnT) and LV dysfunction in early septic shock. METHODS: Forty-six patients were consecutively enrolled, fluid-resuscitated, and treated with catecholamines. Cardiac markers were measured at study entry and after 24 and 48 h. LV function was assessed by two-dimensional transesophageal echocardiography. RESULTS: Increased plasma concentrations of cTnI (>/=0.4 microgram/L) and cTnT (>/=0.1 microgram/L) were found in 50% and 36%, respectively, of the patients at one or more time points. cTnI and cTnT were significantly correlated (r = 0.847; P <0.0001). Compared with cTnI-negative patients, cTnI-positive subjects were older, presented higher Acute Physiology and Chronic Health Evaluation II scores at diagnosis, and tended to have a worse survival rate and a more frequent history of arterial hypertension or previous myocardial infarction. In contrast, the two groups did not differ in type of infection or pathogen, or in dose and type of catecholamine administered. Continuous electrocardiographic monitoring in all patients and autopsy in 12 nonsurvivors did not disclose the occurrence of acute ischemia during the first 48 h of observation. LV dysfunction was strongly associated with cTnI positivity (78% vs 9% in cTnI-negative patients; P <0.001). In multiple regression analysis, both cTnI and cTnT were exclusively associated with LV dysfunction (P <0.0001). CONCLUSIONS: These findings suggest that in septic shock, clinically unrecognized myocardial cell injury is a marker of LV dysfunction. The latter condition tends to occur more often in severely ill older patients with underlying cardiovascular disease. Further studies are needed to determine the extent to which myocardial damage is a cause or a consequence of LV dysfunction.     

Factors at resuscitation and outcome among patients suffering from out of hospital cardiac arrest in relation to age

AIM: To describe various factors at resuscitation and outcome among patients suffering from out-of-hospital cardiac arrest in relation to age. PATIENTS: All patients included in the Swedish Cardiac Arrest Registry during the period 1990-1999. The registry covers about 60% of all ambulance organisations in Sweden. METHODS: All patients reached by the ambulance crew and in whom resuscitative efforts were attempted. Crew witnessed cases were excluded. Only patients aged over 18 years were included. Patients were divided into three age groups: less than 65 years (n=7810), 65-75 years (n=7261) and over 75 years (n=8390). RESULTS: The proportion of cases with a cardiac aetiology increased with increasing age (P<0.0001). The proportion of witnessed cases increased with increasing age among those with a non-cardiac aetiology (P<0.0001) and decreased with increasing age among cases with a cardiac aetiology (P=0.02). The proportion of patients exposed to bystander CPR decreased with increasing age (P<0.0001). The proportion of patients found in ventricular fibrillation (VF) decreased with increasing age among patients with a cardiac aetiology (P<0.0001) but was not related to age in those with a non-cardiac aetiology. The proportion of patients being alive after 1 month in the three age groups (youngest first) were: 4.5, 3.2 and 2.5% (P<0.0001). The corresponding figures for patients with a cardiac aetiology found in VF were: 10.7, 7.6 and 6.6% (P<0.0001). After multiple regression analysis controlling for other factors increasing age was still associated with decreased survival to 1 month (odds ratio 0.85; 95% confidence limits 0.80-0.91). CONCLUSION: Among patients suffering from out-of-hospital cardiac arrest various factors at resuscitation, including initial rhythm, aetiology and bystander CPR, are strongly related to age. The chance of survival diminishes with increasing age. When correcting for the dissimilarities in terms of factors at resuscitation, age is still significantly associated with survival, being lower among the elderly.     

Use and interpretation of cardiac troponins in the ED

Cardiac troponins (cTn) are frequently assessed in patients presenting at the emergency department (ED) with chest pain and various diseases in which myocardial injury may be involved. Cardiac troponins are no longer only used for diagnostic investigations in acute coronary syndrome but may also provide valuable information regarding screening, prognosis, and risk stratification and help to guide therapeutic planning and ED dispositioning of patients with many different types of critical illnesses. Elevation of cTn is usually related to myocardial damage but is not synonymous with acute coronary syndrome. Other etiologies should be considered in the differential diagnosis of a patient presenting with atypical symptoms and elevated cTn, as accurate diagnosis will affect both the initial treatment as well as the initial triage. A thorough knowledge of how to interpret the implications of elevated cTn will allow ED physicians to expand their list of differential diagnoses, facilitate risk stratification and ED disposition, and avoid potential iatrogenic complications resulting from inappropriate interventional therapies.     

Possibilities of achieving target blood pressure in patients with essential hypertension in relation to renal functional status and age

AIM: To study renal functional changes in patients with essential hypertension (EH) and normal blood creatinine levels during antihypertensive therapy with currently available drugs to achieve blood pressure lower than 140/90 mm Hg. MATERIALS AND METHODS: Renal functional changes were studied in 114 patients with EH and normal blood creatinine levels during antihypertensive therapy aimed at achieving blood pressure lower than 140/90 mm Hg. Glomerular filtration rate (GFR) was calculated by the Cockcroft-Gault formula and blood creatinine levels were measured before and 6, 12, 24, 52 weeks of treatment. RESULTS: Renal dysfunction was detected in 43.9% of the patients as GFR < 80 ml/min in 35.1% and hyperfiltration (GFR > 140 ml/min) in 8.8%. The patients with baseline decreased GFR were older, had a longer history of EH, and lower body-mass index than those with hyperfiltration (p < 0.05). There was a considerable renal functional improvement in patients with baseline decreased GFR and achieved BP < 140/90 mm Hg. Target BP could be achieved only in 20% of the patients with hyperfiltration. Antihypertensive therapy caused reduced hyperfiltration in these patients. In patients aged over 60 years who had a baseline GFR < 80 ml/min, achievement of target BP also promoted renal functional improvement. CONCLUSION: Most patients with EH and normal blood creatinine levels have renal dysfunction. Normalization of BP substantially improves renal functional parameters irrespective of age.     

Analytical problems encountered in determining aluminum status from hair in controls and hemodialyzed patients

The problems involved in evaluating aluminum concentrations in hair are reviewed, especially those concerning removal of contaminating metals, a critical factor. In the few published studies of Al concentrations in hair, acetone was usually used for its removal. Here, its use in the washing sequence was found to give less precise results and higher Al values than the use of isopropanol. With isopropanol, the whole analysis can be done in a single tube. We compared results with those in the literature. We found that the Al concentration in the hair of control subjects was not related to sex or hair color and that there was a highly significant (P less than 0.001) difference between values for control subjects and hemodialyzed patients: 126 (SD 58) nmol/g, n = 49, vs 226 (SD 104) nmol/g, n = 39, respectively.     

The incidence and prognostic significance of elevated cardiac troponins in patients with submassive pulmonary embolism

Although the incidence and prognostic significance of elevated cardiac troponins are known in patients with massive pulmonary embolism (PE), few studies have addressed this issue in patients with hemodynamically stable, submassive PE, who comprise the majority of patients presenting with PE. This prospective cohort study was, therefore, designed to determine the incidence and prognostic significance of elevated cardiac troponins in patients with submassive PE. Consecutive patients with acute, symptomatic, submassive PE that was confirmed by objective diagnostic testing were studied. All patients received treatment with either unfractionated heparin or fondaparinux followed by a coumarin derivative and underwent clinical follow-up for 3 months. Cardiac troponin I (cTnI) levels were measured within 24 h of clinical presentation. An elevated cTnI was defined as > 0.5 microg L(-1) and indicated myocardial injury. Major myocardial injury, that is associated with myocardial infarction, was defined by a cTnI > 2.3 microg L(-1). The clinical outcomes were recurrent venous thromboembolism and all-cause death. In 458 patients with submassive PE, the incidence of cTnI > 0.5 microg L(-1) was 13.5%[95% confidence interval (CI): 10.4-16.7], and the incidence of cTnI > 2.3 microg L(-1) was 3.5% (95% CI: 2.0-5.6). An elevated cTnI > 0.5 microg L(-1) was associated with an increased risk of all-cause death [odds ratio (OR) = 3.5; 95% CI: 1.0-11.9], but did not appear to confer an increased risk of recurrent venous thromboembolism (OR = 1.1; 95% CI: 0.2-4.9). In patients who present with submassive PE, an elevated cTnI occurs in about one in seven patients and is associated with a 3.5-fold increased risk of all-cause death.