Creatine-kinase MB mass: age and sex-associated reference limits in two different platforms that use the same method.

BACKGROUND: Recent updated NACB guidelines suggest that troponins are the biomarker of choice for the detection of myocardial necrosis, but the CK-MB mass is still considered an effective and alternative indicator when troponin assays are not available. The aim of the present study was to compare the reliability of two different analytical platforms in establishing the gender-specific 99th percentile for the CK-MB mass. METHODS: Serum samples collected from healthy subjects were investigated in two different laboratories, LAB 1 (354 subjects: 222 men, 132 women; median age, 40 years, range 19-64 years) and LAB 2 (330 subjects: 224 men, 106 women; median age, 41 years, range 18-71 years), in order to determine the CK-MB mass (microg/L) using the Access((R)) CKMB method (Beckman Coulter), a two-site immunoenzymatic sandwich assay, on UniCel DxI 800 (LAB 1) and Access((R)) 2 (LAB 2) analyzers (Beckman Coulter). The related plasma samples (lithium-heparin) were also evaluated in LAB 2. RESULTS: Total imprecision (CV%), calculated in control materials, ranged from 6.00 to 9.05 (concentration range, 3.82-36.37) in LAB 1 and from 7.05 to 5.02 in LAB 2 (concentration range, 3.63-34.18). A statistically significant gender-related difference (p<0.05) was found in the whole population studied, values in men being higher than those in women: median=1.86 vs 1.22; 99th percentile=7.64 vs 5.19. The median values in subjects aged 18-28 years (group 1) were lower than those in the other 4 groups (2-5): 1.12 vs 1.59, vs 1.78, vs 1.95 and vs 2.03. The same age-related trend was also observed for CK-MB plasma values, which were comparable to those observed in the matched-serum samples: median 1.12 vs 1.10 (group 1), 1.45 vs 1.50, (group 5). CONCLUSIONS: The two different analytical platforms provide comparable results. The finding that CK-MB mass values are significantly higher in males than in females represents a relevant information, that will impact on patient classification when a myocardial necrosis has been suspected. Actually, however, numerous assays commercially available, lack of this information.

[Evaluation of an immunoenzymatic method for determining TSH and establishment of reference values]. / Valutazione di un metodo immunoenzimatico per la determinazione del TSH e definizione dei valori di riferimento.

In the present work we reported the results of the valuation of IMx Ultrasensitive hTSH assay which is a Microparticle Enzyme ImmunoAssay (MEIA) for quantitative determination of human stimulating hormone (hTSH) in the human serum or plasma. We have determined the method's precision, within run and between run, sensitivity and recovery. This method has been compared with another one (Immuno RadioMetric Assay). Also reference values have been calculated in the "normal" male and female population and shortly commented.

Effects of 2-deoxy-D-glucose on food intake of rats are affected by diet composition.

The effect of various doses of 2-deoxy-D-glucose (2-DG) on food intake in rats fed either a medium fat diet with a moderate carbohydrate content (MF-rats) or a carbohydrate-free high fat diet (HF-rats) was tested. Injections were given intraperitoneally either in the middle of the bright phase or 1 h after onset of the dark phase. During the light phase 2-DG induced a transient hyperphagia in both HF- and MF-rats, but the hyperphagia was somewhat less pronounced in HF-rats. During the dark phase 2-DG produced a hyperphagia in the MF-rats and a long-term hypophagia in the HF-rats. Since 2-DG elicited feeding in HF-rats during the light phase, the feeding response to 2-DG not only reflects hunger for carbohydrate as previously suggested but also seems to produce hunger for energy.

Serological follow-up of patients involved in a localized outbreak of leptospirosis.

Eighteen patients involved in a localized outbreak of leptospirosis were subjected to a serological follow-up study over a 5-year period. Four distinct sets of sera from all patients and a fifth sample obtained from 10 of them were examined by the microscopic agglutination test (MAT) for demonstration of leptospiral antibodies. The test was carried out by using live leptospires from reference strains of 17 Leptospira interrogans serovars known to occur in Italy. In all cases, the highest titers of agglutinins were recorded against one or more of the three Australis group serovars tested (australis, bratislava, and lora). The highest antibody levels were reached soon after the acute phase of infection in some patients but only after some months in others. Titers then tended to recede with varying rapidity, but titers against the Australis group serovars were still detectable in some patients after 5 years. Coagglutinins against serovars of other serogroups were detected, generally at low levels, in the early sets of sera of most patients, but tended to disappear in the late-set sera. Specific immunoglobulin M (IgM) and IgG against the three Australis group serovars were determined in most serum samples from 16 patients by solid-phase enzyme immunoassay (EIA). In general, EIA titers were considerably lower than MAT titers, but there was a certain patient-to-patient variability in both the IgM/IgG ratio and the evolution and persistence of the two immunoglobulin classes. Since all the evidence indicated that the initial outbreak from a single source, the observed patient-to-patient variability in the progress of both MAT and EIA titers appeared to be attributable to factors inherent in the individual patients. Cross agglutination absorption tests, aimed at retrospectively determining to which of the Australis group serovars the outbreak-specific infecting strain belonged, were performed with six serum samples from different patients. Most absorbed sera seemed to originate from an australis or lora infection, but it was not possible to discriminate conclusively between the two serovars.

Mechanisms of vasopressin's anorectic effect.

The present experiments investigated the effect of vasopressin (VP) on food intake in rats under various conditions. VP (1.25-10 micrograms/kg body weight = b.wt.) injected intraperitoneally (IP) at the onset of the dark phase of the lighting cycle inhibited feeding in a dose-dependent manner. The suppression of feeding induced by VP was primarily due to a delayed onset of the first meal after injection and was reversed by a V1-receptor antagonist (7 micrograms/kg b.wt., IP), by the Ca(++)-channel blocker verapamil (5 mg/kg b.wt., IP) and by the alpha-adrenergic receptor antagonist phentolamine (500 micrograms/kg b.wt.), but not by dissection of the hepatic branch of the vagus. In further experiments VP inhibited gastric emptying. This effect was not reversed by phentolamine. VP had also an aversive effect, but this effect was weaker than that of LiCl and probably not involved in VP-induced hypophagia. The results suggest that VP reduces feeding through a V1-receptor-mediated activation of an alpha-adrenergic mechanism. The inhibition of gastric emptying or a possible stimulation of hepatic oxidative metabolism by VP seems to be not essential for VP's effect on feeding. The results are consistent with a role of VP in stress-induced anorexia in rats.

Hepatic branch vagotomy attenuates the feeding response to 2-deoxy-D-glucose in rats.

The effect of hepatic branch vagotomy on the feeding response induced in rats by intraperitoneally injected 2-deoxy-D-glucose (2-DG) was tested. Injections were given 1 h after onset of the dark phase, and immediately [corrected] after the rats had ingested a meal. 2-DG produced a smaller feeding response in hepatic branch-vagotomized rats compared with that in sham-vagotomized rats. This finding suggests that hepatic glucoreceptors with vagal afferent fibres are involved in the feeding response to glucose deprivation.