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Biomedical subjects

A Clerico

Publications and source records attributed to A Clerico.

At least 73 records · Page 4Linked to original sources
PubMed1993

Symptomatic congenital cytomegalovirus infection in two consecutive sisters.

The occurrence of symptomatic congenital cytomegalovirus (CMV) infection in two consecutive sisters is reported. The first sibling showed hepatosplenomegaly with slight hyperbilirubinaemia and abnormal liver function tests, right inguinal hernia, and peripheral lymphoedema. Her sister, the product of an uneventful pregnancy showing no signs of CMV reactivation, had life threatening CMV disease, including microcephaly, hepatitis with high serum bilirubin concentrations, and thrombocytopenic purpura.

Cytomegalovirus Infections↗
PubMed1993

ANP kinetics in normal men: in vivo measurement by a tracer method and correlation with sodium intake.

125I-labeled atrial natriuretic peptide (ANP) was bolus injected into seven healthy human male subjects on an unrestricted diet (sodium intake ranging from 80 to 300 mmol/day). A high-performance liquid chromatographic procedure was used to purify the labeled hormone and the principal labeled metabolites in venous plasma samples collected up to 50 min after injection. The main ANP kinetic parameters were derived from the disappearance curves of the 125I-ANP, which were satisfactorily fitted by a biexponential function in all subjects. Newly produced ANP initially distributes in a large space (plasma-equivalent volume is 12.1 +/- 3.6 l/m2 body surface); the hormone rapidly leaves this sampling space through both degradation and distribution in peripheral spaces, as indicated by the single-pass mean transit time through the sampling space (3.9 +/- 1.2 min). The mean residence time in the body (22.7 +/- 23.1 min) and the plasma-equivalent total distribution volume (30.9 +/- 12.0 l/m2) indicate that ANP is also widely distributed outside the initial space. Metabolic clearance rate (MCR) values were distributed across a wide range (from 740 to 2,581 ml.min-1 x m-2) and were shown to correlate strongly with the daily urinary excretion of sodium. These results indicate that: 1) newly produced ANP is rapidly distributed and degraded, 2) the body pool of the hormone can be considered as a combination of two exchanging spaces, 3) circulating ANP is < or = 1/15 of the body pool, and 4) MCR of ANP is closely related to sodium intake, at least in normal subjects on a free sodium intake diet.

Adult↗
PubMed1993

Immunoradiometric assay of serum myosin as a marker of myocardial cell damage: methodological and clinical evaluation.

We evaluated the performance and analytical parameters of a one-step magnetic IRMA kit for the measurement of myosin in serum. The method uses two monoclonal antibodies selected for their high affinity to the heavy chains of human ventricular myosin. The first antibody is coupled to a magnetic solid phase and the second one is labeled with 125I. The working range of the IRMA (range of myosin concentrations measured with an imprecision < 10% CV) was 250-3600 microU/L and the sensitivity 20.8 +/- 7.2 microU/L. The between-assay variability, evaluated from replicate measurements in different runs of two serum pools was 14.6 CV% for the first pool (259.1 +/- 37.8 microU/L) and 14.3 CV% for the second pool (442.0 +/- 63.1 microU/L), respectively. To evaluate the clinical usefulness of myosin as a marker of myocardial cell damage, serum myosin was measured in patients with acute myocardial infarction (AMI) (n = 9) or subarachnoid hemorrhage (n = 20). The results obtained with the myosin assay were compared with those of two other markers considered specific for myocardial necrosis (CK-MB and myoglobin). In eight patients with AMI, serum myosin was elevated 24-36 hours after the onset of chest pain and reached a maximum at 4-7 days, returning to control levels at 8-11 days. The one remaining AMI patient showed two subsequent peaks in serum CK-MB and myoglobin concentrations (thus suggesting an extension of myocardial necrosis), the myosin concentrations reaching their peak only after 9 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers↗
PubMed1993

Performance of a fully automated fluorometric enzyme immunoassay for serum myoglobin measurement.

An automated fluorometric enzyme immunoassay system for the determination of serum myoglobin has been recently developed. This method is based on the sandwich immunoassay and uses two mouse monoclonal antimyoglobin antibodies; the first one is complexed onto glass fiber paper and the second is conjugated to an enzyme alkaline phosphatase which reacts with the substrate 4-methylumbelliferyl phosphate to generate a fluorescent product. Using a dedicated automated apparatus the time to the first result is eight minutes, with additional values being produced at one-minute intervals (about 50 samples/hour). We compared the analytical performance of this fluorometric enzyme immunoassay with that of a RIA set up in our laboratory for the routine assay of serum myoglobin. The automated fluorometric enzyme immunoassay showed lower between-assay variability (CV = 4.7% vs 13.8%) and higher sensitivity (0.3 ng/mL vs 7.2 ng/mL) than the manual RIA. Moreover, the two immunoassays gave similar results when serum samples of normal subjects and patients with coronary artery disease with or without acute myocardial infarction (AMI) were assayed (fluorometric immunoassay = -0.7 + 0.851 RIA, r = 0.991, n = 137). In conclusion, the automated fluorometric enzyme immunoassay tested in the present study produces reliable clinical results with a rapid turnaround time and therefore can be recommended for use in the early detection of AMI in a laboratory of Coronary Care Unit.

Evaluation Studies as Topic↗
PubMed1993

How and how long to store urine samples before albumin radioimmunoassay: a practical response.

We used three study protocols to check the dependence of albumin stability, measured by an RIA, on different temperatures, durations, and materials (i.e., assay tubes) of urine storage. Albumin values obtained for samples stored in three types of assay tubes (glass, polystyrene, and polypropylene) throughout the 2 months of the first (prospective) protocol were superimposable. The 24-h storage of six urine samples at room temperature or at 4 degrees C, as well as 72-h storage at 4 degrees C, did not affect the albumin measurement by RIA. After 2 months of storage of these same six urine samples at -20 degrees C, there was still no albumin decrease. A significant albumin decrease occurred (a mean of approximately 5% per year, throughout the range of albumin concentrations tested) when samples stored at -20 degrees C were reassayed by RIA after > or = 2 years (second protocol, retrospective). Finally, 3 of 21 (14.3%) urine pools stored at -20 degrees C for various periods (4-21 months) showed a significant albumin loss after storage; the time of storage as well the decrement rates of these 3 pools differed from each other (third protocol, retrospective). Short- and medium-term (2-6 months) freezing of urine samples at -20 degrees C does not significantly affect the stability of immunoreactive albumin. For longer preservation periods, storage of urine samples at -70 degrees C may be preferable.

Albuminuria↗
PubMed1992

Which method for quantifying "microalbuminuria" in diabetics? Comparison of several immunological methods (immunoturbidimetric assay, immunonephelometric assay, radioimmunoassay and two semiquantitative tests) for measurement of albumin in urine.

We have compared the chemical and clinical characteristics of an immunonephelometric assay (INA), two immunoturbidimetric assays (ITA) and two semi-quantitative methods with those of a solid-phase radioimmunoassay (RIA) for measurement of urinary albumin (UA) concentration in 136 diabetic patients. INA and RIA had similar accuracy, and provided comparable results. However, RIA has slightly greater sensitivity than INA, which is easier and faster. Good agreement was also found between RIA and the two ITA methods, although one of these overestimated RIA values in the low-medium range (5-30 mg/l) of urinary albumin. ITA seems suitable for initial screening of albuminuria in diabetic patients but more sensitive procedures (such as RIA and INA) seem preferable for measurement of UA concentrations in the normal range. The two semi-quantitative methods showed high sensitivity but poor specificity, because of the large number of false positive results. About 50% of diabetic patients "positive" by these methods did not have microalbuminuria. The utility of these methods is questionable, because many samples from diabetic patients need to be reassayed by a more specific and sensitive assay such as the RIA, INA or ITA methods.

Albuminuria↗
PubMed1992

Effects of the administration of thyroid hormone on the plasma levels of atrial natriuretic peptides and on atrial myoendocrine cells in the rat: an immunochemical, ultrastructural, and stereological study.

The effects of an altered thyroidal status on the levels of immunoreactive (ir-) atrial natriuretic peptide (ANP) in serum and in the right and left atria, as well as on the subcellular structures of atrial myoendocrine cells were explored in groups of male Sprague Dawley rats given the vehicle or triiodothyronine in the toxicological dose-range (50 micrograms/100 g bw/day) for 0,5, 1,2,4,7 or 14 days. Plasma levels of ir-ANP were 30% higher in T3-treated rats compared with controls at 0,5 and 1 day after hormone administration and then decreased to levels 30-40% lower than controls at days 2 and 4 to rise again above control values on day 7 and 14. Atrial ir-ANP levels decreased at first both in the right and in the left atria with different latencies (1 and 2 days, respectively) and rose back towards control levels by day 4. Changes in the numerical density of specific granules followed a parallel temporal pattern. An increased in the individual volume of the granules followed was also observed. Investigation into the circulatory effects of T3 administration showed that the heart rate was increased by hour 12 after hormone administration (simultaneously with the early rise in plasma ir-ANP levels) and that blood pressure was increased by day 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Role of endothelin-1 in carrageenin-induced inflammation.

Many vasal factors are produced during an experimental model of inflammation such as rat-paw oedema induced by carrageenin. We investigated whether among the other well-known mediators of inflammation, i.e. serotonin, PAF, eicosanoids and kinins, the peptide endothelin-1 is produced by this kind of inflammatory process caused by carrageenin. Our results indicated that plasma endothelin, and the tissue concentration of endothelin in the oedematous paw, is increased as compared to the control. Consequently, endothelin should also be considered as an important factor in inflammatory processes.

Animals↗
PubMed1992

Endogenous digitalis-like factors in human milk.

We measured the concentration of endogenous digitalis-like factors (EDLFs) in milk or colostrum of women during nursing on different days after delivery. EDLF concentrations were assayed by a solid-phase RIA involving antidigoxin antibodies and by a radioreceptor assay (RRA) involving human placenta Na+/K(+)-ATPase. The mean (SD) EDLF concentrations as measured by RIA were 35.6 (19.4) ng of digoxin equivalents per liter in milk samples (n = 37) and 61.3 (12.5) ng/L in colostrum samples (n = 5); the mean EDLF concentration as measured by RRA in milk samples (n = 11) was 573 (717) ng/L (range 0-2098). EDLF concentration in milk is greater than circulating concentrations in healthy adults but is comparable with serum concentration in the third trimester of pregnancy. In milk and serum samples (n = 8) collected at the same time, heating and (or) extracting with Sep-Pak C18 cartridges before the RIA produced significantly different EDLF values from those in untreated serum (P less than 0.001) and milk (P = 0.035). EDLF in milk appeared to be not bound or weakly bound to milk protein, as indicated by the fact that boiling did not increase the digoxin-like immunoreactivity.

Blood Proteins↗
PubMed1992

Interassay variability of immunometric methods for thyrotropin in an external quality assessment survey: evidence that functional sensitivity is not always adequate for clinical decisions.

We investigated the ability of current immunometric methods for thyrotropin (TSH; thyroid-stimulating hormone) to distinguish between low-normal and subnormal hormone concentrations by using the data from an external quality assessment (EQA) survey in 1990. We computed the interassay (between-run) precision profiles from results from 101 laboratories, which used the five most popular kits in the survey; during the control period (one year) each laboratory assayed 4 EQA pools distributed (as hidden replicates) in five occasions. The interassay CV was relatively low (9-13%) for three pools in the normal TSH range (greater than 0.8 milli-int. unit/L) but markedly higher (30-40%, except for one more precise kit) in the subnormal range (0.2 milli-int. unit/L). We calculated the effect of the between-run variability on the diagnostic accuracy (discrimination between normal and subnormal values) for three representative TSH concentrations: 0.2, 0.4, and 0.5 milli-int. unit/L (0.3 milli-int. unit/L was considered the lower normal limit). The three concentrations were reasonably discriminated (P less than or equal to 5%), and only one kit showed a between-run CV less than 18% at 0.2 milli-int. unit/L. For the other four less-precise kits, only the higher TSH value (0.5 milli-int. unit/L) could be classified with an acceptable diagnostic reliability. With the most precise kit, one can distinguish two TSH concentrations in the 0.3-0.5 milli-int. unit/L range that differ by at least 30%; with the other kits, differences greater than 50-60% are needed for reliable discrimination. Thus many laboratories fail to achieve the functional sensitivity of a second-generation assay, even if they use immunometric methods. TSH assays with a better interassay precision in the low concentration range are needed.

Humans↗
PubMed1991

Functionally active ganglioneuroma with increased plasma and urinary catecholamines and positive iodine 131-meta-iodobenzylguanidine scintigraphy.

Ganglioneuromas are usually considered not to be functionally active. Studies of their catecholamine excretory pattern and of their imaging by means of the adrenergic tracing agent 131-I-MIBG have been therefore sparse. We report on a case of secretory ganglioneuroma, as demonstrated by the increased urinary excretion of the catecholamine metabolites HVA and VMA, increased plasma dopamine and epinephrine levels, and positive 131-I-MIBG scintigraphy. We must therefore be aware that a functionally active tumor is not necessarily a neuroblastoma, and that the diagnosis should be biopsy proven.

3-Iodobenzylguanidine↗