A sensitive and rapid mass spectrometric method for the simultaneous measurement of eight steroid hormones and CALIPER pediatric reference intervals.

OBJECTIVES: To develop an accurate assay and establish the normal reference intervals for serum cortisol, corticosterone, 11-deoxycortisol, androstenedione, 21-hydroxyprogesterone, testosterone, 17-hydroxyprogesterone, and progesterone. These steroids are commonly used as biomarkers for the diagnosis and monitoring of endocrine diseases such as congenital adrenal hyperplasia. Appropriate age- and gender-stratified reference intervals are essential in accurate interpretation of steroid hormone levels. DESIGN AND METHODS: The samples analyzed in this study were collected from healthy, ethnically diverse children in the Greater Toronto Area as part of the CALIPER program. A total of 337 serum samples from children between the ages of 0 and 18years were analyzed. The concentrations were measured by using an LC-MS/MS method. The data were analyzed for outliers and age- and gender-specific partitions were established prior to establishing the 2.5th and 97.5th percentiles for the reference intervals. RESULTS: Reference intervals for all hormones required significant age-dependent stratification while testosterone and progesterone required additional sex-dependent stratification. CONCLUSIONS: We report a sensitive, accurate and relatively fast LC-MS/MS method for the simultaneous measurement of eight steroid hormones. Detailed reference intervals partitioned based on both age and gender were also established for all eight steroid hormones.

Influence of fasting and sample collection time on 38 biochemical markers in healthy children: a CALIPER substudy.

OBJECTIVES: Fasting samples can be difficult to obtain in the pediatric setting, particularly in neonates. As part of the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER), we aimed to determine if there are differences in serum concentrations of pediatric biochemical markers measured at fasting, postprandial, and random time points throughout the day. DESIGN AND METHODS: Blood was drawn from 27 healthy children and adolescents (aged 4-18) with informed consent at 4 time points: after overnight fast, mid-morning after breakfast, within 2h after lunch, and late afternoon. The effect of fasting on 38 chemistries was evaluated by paired, two-tailed student'st-tests. Analysis of the effect of time of day was done using paired, repeated-measures ANOVA. RESULTS: Fasting significantly affected 22 analytes, with HDL cholesterol being the most highly affected. Values tended to decrease postprandially, except for five analytes, including triglycerides, which increased. By ANOVA, 28 chemistries significantly differed across times of day tested. CONCLUSIONS: Fasting is necessary for analysis of certain chemistries in pediatric subjects. Pediatricians should consider diurnal factors when ordering non-fasting tests and interpreting test results.

Paradoxical low nasal nitric oxide in nasal polyposis.

BACKGROUND: Nitric oxide (NO) is synthesized in the respiratory tract. Three isoforms of NO synthase have been described in man, with the inducible form related to inflammatory disease. In the paranasal sinuses constitutive production of nitric oxide has been demonstrated, with levels of 20-25 p.p.m. being found in sinus puncture. Nasal polyposis is a chronic inflammatory condition in which inducible nitric oxide synthase (iNOS) expression is elevated in nasal polyp epithelium. OBJECTIVES: 1. Measurement of upper airway nitric oxide in nasal polyposis patients compared with those with allergic rhinitis, and with normal controls. 2. To assess the effect of polyp treatment on nasal NO levels. METHODS: NO levels (parts per billion) were measured in nasal and pulmonary exhaled air using a LR 2000 Logan Sinclair nitric oxide gas analyser. This utilizes the chemiluminescence principle. Eighty-two patients were studied: 44 with rhinitis, but without polyps, and 38 with nasal polyps. NO levels were compared with those of 20 normal controls. In 23 further polyp patients, levels were measured pre- and post-treatment and the changes were compared with alterations in polyp size, as assessed by rigid nasendoscopy. RESULTS: Nasal NO levels were significantly lower (Kruskal-Wallis, P = 0.000, chi2 = 27.5, d.f. = 3) in patients with polyps than those found in uncomplicated allergic rhinitis. NO levels were correlated directly with extent of polyposis as graded by the Lund-McKay index. Successful treatment, with reduction in polyp volume, was associated with a rise in NO levels (P = 0.042). CONCLUSION: NO levels are low in nasal polyposis, despite high levels of iNOS, possibly related to blockage of the ostiomeatal complex and failure of NO generated constitutively in the sinuses to reach the nasal airway. A rise in the NO levels is seen with successful polyp treatment, and is proportional to the reduction in endoscopically assessed polyp size, suggesting that with both medical and surgical therapy, the ostiomeatal complex obstruction is decreasing. We propose the following scenario. Nasal NO levels are the result of two processes: inducible NO production by inflamed nasal mucosa plus constitutive sinus mucosal production, detectable in normals. In uncomplicated allergic rhinitis with patent sinus ostia NO levels tend to be elevated, but when inflammation is sufficient to obstruct sinus ostia (as in nasal polyps), NO levels fall because sinus NO makes the major contribution.

A novel mechanism for myocardial stunning involving impaired Ca(2+) handling.

The mechanism of myocardial stunning has been studied extensively in rodents and is thought to involve a decrease in Ca(2+) responsiveness of the myofilaments, degradation of Troponin I (TnI), and no change in Ca(2+) handling. We studied the mechanism of stunning in isolated myocytes from chronically instrumented pigs. Myocytes were isolated from the ischemic (stunned) and nonischemic (normal) regions after 90-minute coronary stenosis followed by 60-minute reperfusion. Baseline myocyte contraction was reduced, P<0.01, in stunned myocytes (6.3+/-0.4%) compared with normal myocytes (8.8+/-0.4%). The time for 70% relaxation was prolonged, P<0.01, in stunned myocytes (131+/-8 ms) compared with normal myocytes (105+/-5 ms). The impaired contractile function was associated with decreased Ca(2+) transients (stunned, 0.33+/-0.04 versus normal, 0.49+/-0.05, P<0.01). Action potential measurements in stunned myocytes demonstrated a decrease in plateau potential without a change in resting membrane potential. These changes were associated with decreased L-type Ca(2+)-current density (stunned, -4.8+/-0.4 versus normal, -6.6+/-0.4 pA/pF, P<0.01). There were no differences in TnI, sarcoplasmic reticulum Ca(2+) ATPase (SERCA2a), and phospholamban protein quantities. However, the fraction of phosphorylated phospholamban monomer was reduced in stunned myocardium. In rats, stunned myocytes demonstrated reduced systolic contraction but actually accelerated relaxation and no change in Ca(2+) transients. Thus, mechanisms of stunning in the pig are radically different from the widely held concepts derived from studies in rodents and involve impaired Ca(2+) handling and dephosphorylation of phospholamban, but not TnI degradation.

Circadian rhythm of peak expiratory flow in children passively exposed and not exposed to cigarette smoke.

BACKGROUND: Because airway calibre shows a circadian rhythm and since exposure to passive smoking reduced lung function this study was undertaken to investigate whether passive smoking affects the circadian rhythm of peak expiratory flow (PEF) in schoolchildren. METHODS: Twenty schoolchildren (12 boys and 8 girls, aged 10-11 years) exposed to passive smoking were matched for sex, age, and height with 20 children who had not been exposed to cigarette smoke. Exposure to passive smoking was assessed by questionnaire and by urinary cotinine concentrations. A portable spirometer was used to measure PEF at 16:00, 20:00, 22:00, 06:00, 08:00, and 12:00 hours on a consecutive Saturday and Sunday. The circadian changes in PEF were measured by the cosinor method. RESULTS: Both groups showed diurnal fluctuation in PEF values with a noticeable circadian rhythm. PEF peaks were the same in the two groups and occurred around 15:00 hours. The cosinor mean was approximately 10% lower in children exposed to passive smoking and the amplitude was approximately 60% higher than in the unexposed children. CONCLUSION: Passive smoking in children is associated with a reduction in the cosinor mean and an increase in the amplitude of the normal circadian rhythm of airway calibre. This increased PEF rhythm amplitude may be considered as an early indication of airway obstruction.

Persistence of human growth hormone circadian rhythm in patients with homozygous beta-thalassemia.

Plasma levels of human growth hormone (hGH) were measured for an entire day every two hours, starting from midnight, in 6 healthy male subjects and in 6 male patients with homozygous beta-thalassemia, without evidence of any endocrine disease. The data were analyzed by the "cosinor" method, and the results show the presence of a significant (p < 0.05) circadian rhythm for hGH in both groups. Whereas no differences were found in mesors and acrophases between the two studied groups (p > 0.05), a statistically-significant (p < 0.05) difference was observed regarding amplitudes, being higher in the controls. These data suggest that in patients with beta-thalassemia major without evidence of any endocrine abnormality, the circadian secretory pattern of hGH is preserved, even if the rhythm amplitude is reduced: this could be a compensatory mechanism in order to stimulate growth.

Prognostic value of the plasma cell synthesis score in multiple myeloma.

The prognostic value of the Plasma Cell Synthesis Score (PCSS) has been tested in a group of 140 patients with multiple myeloma followed up from diagnosis to death. Calculation of PCSS, based on the regression coefficients obtained by multivariate regression analysis according to Cox's model, was performed according to the formula: [formula: see text] Substratification into three risk groups was performed as follows: low risk = PCSS more than 70; moderate risk = PCSS between 50 and 70; high risk = PCSS less than 50. Significant differences were found among the three stages regarding median survivals (p less than 0.005), survival curves (p less than 0.000000001), and response to therapy (p less than 0.00001). A positive significant relationship was demonstrated between calculated PCSS and survival in the whole group (p less than 0.000001). PCSS could be a good estimation of bone marrow plasma cell differentiation, and therefore could be a useful prognostic parameter in multiple myeloma.

Occupational risk for hematological malignancies.

A case-control study was conducted in 620 cases of hematological malignancies and in 1,240 age- and sex-matched controls in order to verify the possible association between occupation, toxic substances exposure, and the risk of hematological neoplasias. The results demonstrate that farmers and industrial workers have a significant risk for hematological malignancies. Exposure to asbestos, aromatic hydrocarbons, fertilizers, mineral oils, pesticides, and radiations is associated with a significant increase in the risk for these malignant diseases. These data are in agreement with previously reported data, and require a confirmation in larger, prospective studies.

Plasma levels of atrial natriuretic peptide after exercise.

The plasma levels of atrial natriuretic peptide were determined before, at the end of exercise performed on a bicycle ergometer at constant 200-W for 10 minutes, and at 30 minutes after the end of test in 8 clinically healthy male subjects. The results show that plasma atrial natriuretic peptide levels increase significantly at the end of test, and return to baseline values after 30 minutes. The increase in atrial natriuretic peptide levels is significantly correlated with the increase in heart rate and in systolic arterial blood pressure. These data indicate that the plasma levels of atrial natriuretic peptide increase in response to exercise proportionally to the intensity of workload: in this respect, exercise is an useful test in order to evaluate the endocrine function of the heart.

Isolated atrial myocardial infarction: pathological and clinical features in 10 cases.

Isolated myocardial infarction of the atria is a relatively understudied and underestimated entity, rarely diagnosed in life. The pathological and clinical features in 10 cases of acute isolated atrial myocardial infarction are reported. They represent 3.5% of all myocardial necrosis out of a series of 2,704 consecutive autopsies in adults. The right atrium is more frequently involved than the left atrium (9:1). Pulmonary hypertension, with or without coronary arterial narrowing, is the major condition leading to isolated atrial infarction. Congestive heart failure, thromboembolic phenomena, and supraventricular arrhythmias are the most frequent complications of atrial infarction. The electrocardiographic findings are often non-specific and elusive and are not useful to a correct diagnosis. These observations suggest that isolated atrial myocardial infarction is a well-distinct entity with respect to ventricular myocardial infarction, since there are several differences between the 2 diseases in pathogenesis, diagnosis, clinical picture, and prognosis.

Classification and prognostic evaluation in multiple myeloma. A retrospective study of relationship of survivals and responses to chemotherapy to immunological types, 20 single prognostic factors, 15 clinical staging systems, and 6 morphological classifications.

In a group of 136 completely followed up patients with multiple myeloma, the prognostic significance of the immunological myeloma types, of 20 different single prognostic factors, of 15 clinical staging systems, and of 6 morphological classifications was retrospectively investigated by means of the calculation of mean survivals, survival curves, and responses to chemotherapy. A univariate analysis was employed in order to correlate each prognostic parameter at presentation with the survival in the whole group; a multivariate analysis according to the Cox's hazards regression model was used in order to select the most powerful prognostic variables. The patients were grouped according to the myeloma immunological types, to the mean value of each single prognostic factor, and to each stage of the clinical and morphological systems. Causes of death were also related to immunological multiple myeloma types. All single variables, except age and serum calcium, presented a significant relationship with the survival, even if at different significance levels. Cox's regression model selected among them, serum levels of beta 2-microglobulin, percentage of bone marrow plasma cells, hemoglobinemia, lytic bone lesions, and Bence-Jones proteinuria as the most significant factors related to survival. Each clinical and morphological staging system divided groups of patients with significant differences in mean survivals, or in survival curves, or in response to therapy. Multiple myeloma type IgA and micromolecular, with Bence-Jones proteinuria, and type lambda were associated with a poor prognosis, with low therapeutical response, and with the development of fatal renal failure. All these parameters, together with new prognostic factors, are useful in the prognostic evaluation, and, when applied in different steps of the diagnosis and the therapy, allow of studying the clinical course of multiple myeloma under different perspectives, in order to have a more complete picture of the disease and of the single patient.

Short-term effects of atenolol and nifedipine on atrial natriuretic peptide, plasma renin activity, and plasma aldosterone in patients with essential hypertension.

The short-term effects of atenolol and nifedipine on plasma levels of atrial natriuretic peptide (ANP), plasma renin activity (PRA), and plasma aldosterone (PA) were studied in two groups of patients with uncomplicated essential hypertension. Urinary catecholamines, and sodium and potassium excretion were also studied. A group of 20 patients with hypertension, after a wash-out period of at least 10 days, was randomly subdivided into two protocol therapy subgroups. One group (six men and four women) received atenolol (100 mg/d), and the other group (six men and four women) received nifedipine (30 mg/d). Circulating plasma levels of ANP, PRA, and PA were determined by radioimmunoassay, and other variables were determined by routine laboratory techniques before therapy and at day 3 and day 7 after the treatment began. Arterial blood pressure and heart rate were monitored during the study. Both drugs reduced arterial blood pressure (P less than .001) significantly. The atenolol therapy decreased heart rate (P less than .001), increased plasma ANP levels and urinary catecholamine excretion, and decreased PRA and circulating PA levels. Nifedipine treatment did not modify plasma ANP values, whereas it increased PRA and PA circulating levels and urinary catecholamine excretion. No differences were shown for urinary volume, urinary sodium, and potassium excretions during the two different treatments. These findings suggest that the increased plasma ANP levels could contribute to the antihypertensive effects of the beta-adrenoreceptor blockers, by a reduction in PRA and PA levels and a vasodilatative effect.(ABSTRACT TRUNCATED AT 250 WORDS)

[Epidemiologic chronorisk of acute cardio-cerebrovascular diseases]. / Cronorischio epidemiologico della malattie cardiocerebrovascolari acute.

This review summarizes the accumulated data demonstrating that several cardio-cerebrovascular diseases do not occur with casual periodicity, but present a predictable critical time of ultradian, circadian, or infradian recurrence in their onset. In fact, during the last years, it has been clearly established that there is a prominent increase in a definite period of the day, of the week, and of the year in the frequency of onset of acute myocardial infarction, sudden cardiac death, stroke, and fatal pulmonary thromboembolism. Morning hours, week-end, and winter seem to be the periods at higher risk, since a number of physiological processes that could contribute to the onset of the disease are intensified. Also environmental and behavioural conditions could contribute to these peaks. Consequently, the periodicity in the occurrence of these diseases may be due to the relationships between the exogenous factor rhythms, the endogenous biological rhythms, and the disease. These epidemiological and chronopathological observations suggest the introduction of time as a measurable structure for the clinical risk, and the term "chronorisk" as a predictable condition of temporally periodic or permanent risk for human health, which is generated by a temporal-quantitative disorder in the physiological course of the biological oscillating functions. The temporal recurrences in the onset of the acute diseases are not only epidemiological data, but, since the reasons for these rhythm changes in pathology are likely multifactorial, the study of such rhythms will probably help in the understanding of the pathogenesis and the triggering mechanisms. Moreover, further investigations of these rhythmicities may help the planning of more effective preventive therapy.

A possible role of atrial natriuretic peptide in ethanol-induced acute diuresis.

The acute effects of ethanol on plasma atrial natriuretic peptide levels were investigated in 4 clinically healthy males, aged 24-26 years, consumed either 750 ml of water as a control study, or the same beverage with 1 ml/kg alcohol added, which increased the plasma alcohol concentration to 99.12 +/- 15.10 mg/dl at 60 min. Plasma atrial natriuretic peptide levels were significantly higher in the alcohol study compared to the control study at each time point (10, 20, 30, 60, 120 min after drinking onset), and with a peak at 10 min. Atrial natriuretic peptide levels showed a positive significant correlation with plasma antidiuretic hormone in the control group, while no relationship was found between the two peptides in the alcohol study. Moreover, a significant correlation exists between plasma atrial natriuretic peptide levels and systolic arterial blood pressure, and heart rate, and between the variations in atrial natriuretic peptide values and the variations in plasma sodium, serum ethanol, and plasma osmolality in the alcohol study. Acute ethanol intake causes an increase in urinary volume, and a decrease in urinary potassium excretion and urinary osmolality, and no change in urinary sodium excretion. These data suggest that acute ethanol administration causes a rapid increase in plasma levels of atrial natriuretic peptide, which could be an important factor of ethanol-induced diuresis. The main mechanisms for increased atrial natriuretic peptide release from atria after acute ethanol ingestion seem to be atrial stretch, due to the increase in arterial blood pressure, in heart rate, in sympathetic tone, and in plasma osmolality, and to a direct secretory effect by antidiuretic hormone.

Prognostic factors in multiple myeloma: a new staging system based on clinical and morphological features.

A new staging system for multiple myeloma based on clinical and morphological features has been developed on the analysis of 190 patients. A score of "1" was assigned to each of the following clinical data, referred at the time of diagnosis, and selected by multivariate analysis: bone marrow plasma cells more than 30%, haemoglobin less than 110 milligrams, lytic bone lesions of degree 2 or 3, serum beta 2-microglobulin levels higher than 678 nmol/l, and presence of Bence-Jones proteinuria. Therefore, the score for each patient ranged from 0 to 5, and three clinical stages were provided: I = 0 or 1, II = 2 or 3 and III = 4 or 5. Substratification into A and B for each clinical stage was performed using multiple myeloma cellular score, calculated by the formula: total bone marrow myeloma cells per 500 cells x 0.752 + bone marrow plasmablasts per 500 cells x 0.709. Substage A corresponded to multiple myeloma cellular score value lower than 0.300, and substage B to a value greater than 0.300. Significant differences were found in median survivals (P less than 0.0001), in survival curves (P less than 0.0001), and in responses to treatment (P less than 0.0001) among the six staged groups. The use of this staging system for multiple myeloma could offer new prognostic information and could better quantify the picture of the disease in each patient. The substaging according to morphological criteria seems very useful in diminishing or eliminating the great prognostic variability observed within the same clinical stage. Confirmatory studies are required to validate this new staging system for multiple myeloma.

Impaired pulmonary function in schoolchildren exposed to passive smoking. Detection by questionnaire and urinary cotinine levels.

Pulmonary function was evaluated by FEV1, FVC, PEF, MEF50%FVC, MEF25%FVC and MMEF in relation with passive smoking exposure in 143 children aged 6-11 years (mean age = 8.5 +/- 1.6). Passive smoking exposure was evaluated by a questionnaire and by measurement of urinary cotinine levels. Children were divided into different groups: no exposure, low exposure and high exposure. The mean values of each pulmonary function test were compared between the groups and between the different evaluations by Student's test. The evaluation of passive smoking exposure by questionnaire and by urinary cotinine levels separated homogeneous groups of children. The urinary cotinine levels were significantly lower in the non-exposed children than in the other groups (p less than 0.001). Pulmonary function tests, especially MEF50%FVC, MEF25%FVC and MMEF were significantly reduced in exposed subjects (p less than 0.05). These alterations are an index of early involvement of the small airways also in passive smokers. The greater the exposure to passive smoking, the lower the values of the pulmonary function tests.

Diurnal variations of serum beta 2-microglobulin in multiple myeloma.

The chronobiological circadian behaviour in serum levels of beta 2-microglobulin has been investigated in three groups of subjects: (A) 6 healthy controls; (B) 6 patients with untreated multiple myeloma; (C) 6 patients with multiple myeloma in complete remission after polychemotherapy. From all subjects, under the same standard life conditions, venous blood samples were drawn at 4-hour intervals starting from midnight during the span of a whole day. Circulating serum beta 2-microglobulin levels were determined by RIA method. The time-related data were analyzed by chronograms and the "mean-group cosinor" method. A significant circadian rhythm for serum beta 2-microglobulin was detected in the control group, with a peak in the morning hours, and in untreated patients, with a peak in the afternoon hours. No significant rhythm was found in treated patients with multiple myeloma. A significant mesor reduction was noted in patients with complete remission, correlated with the absence of circadian rhythm, in respect to untreated patients. These data suggest that serum levels of beta 2-microglobulin could be related to the neoplastic plasma cell proliferation and to the effect of therapy, and that the circadian evaluation could be used as a guide in monitoring myeloma patients.