Ligurian experience on neonatal hearing screening: clinical and epidemiological aspects.

AIM: Early identification and rehabilitation of newborns with congenital hearing impairment (HI) by Universal Neonatal Hearing Screening (UNHS). METHODS: The neonatal population was divided into two groups: babies with No Audiological Risk (NAR), and babies With Audiological Risk (WAR). NAR neonates underwent OAE testing, and in case of a doubtful (Refer) result, ABR testing was carried out. All WAR newborns underwent ABR testing within the third month of life. RESULTS: Between February 1, 2002 and December 31, 2004, UNHS was carried out on 32 502 newborns at the 13 regional birth centres, representing 98.7% of the whole regional neonatal population. The prevalence of HI in the population we tested was estimated at about 1 per thousand, while Bilateral Hearing Impairment (BHI) was estimated at 0.65 per thousand. A 3.7% prevalence of HI and a 2.8% prevalence of BHI was observed among the WAR population. Median age at the end of the diagnostic procedures was 6.7 months in the WAR population and 6.9 months in the NAR population. CONCLUSIONS: Our project is based on two levels of testing, which resulted in a 0.28% false-positive rate with 100% sensitivity and 99% specificity. Our screening is the first Italian experience that has been extended to a whole region and the results prove that regional neonatal hearing screening is feasible.

Neonatal hearing screening model: an Italian regional experience.

OBJECTIVE: To produce a model for routine centralized hearing screening including all aspects of the screening, from diagnosis to psychological counseling and early rehabilitation. METHODS: A prospective observational study on a geographically defined pediatric population (Liguria region, northwestern Italy) and data collection in a data bank. The model proposed was created for the audiological screening of all newborns of the Liguria region. The model includes four phases: (1) preliminary identification of contractual, administrative, legal aspects; (2) screening for identification of congenital hearing impairment; (3) therapy and rehabilitation of identified subjects and genetic analysis; (4) epidemiology, data management, and workload management. To test the feasibility of the model proposed and to establish the workload required according to the resources available in the regional health plan, we performed a pilot study on all infants born in four of the 13 regional birth centers of Liguria region from 1 April 2001 to 30 September 2001. RESULTS: Out of the 3268 newborns enrolled during the 6-month pilot study, 3238 (99.1%) were screened with otoacoustic emissions (OAE), while screening was refused in 30 newborns (0.9%). OAE resulted in a 'pass' for 3180 newborns (98.2%) and a 'refer' in 58 (1.8%). The standard auditory brainstem response (ABR) test was performed in 156 newborns, 58 of them as a result of the 'refer' at the second OAE and 98 others at audiological risk. Results were positive or uncertain at first ABR in 45 patients. Workload was calculated on the basis of the data obtained in the pilot study to allocate financial and organizational resources. CONCLUSIONS: The results of the pilot study allowed project planning. We think that the screening model proposed is an example of how a regional organization can deliver improved quality care through a rationalization and optimization process.

Involvement of semicarbazide-sensitive amine oxidase in tresperimus metabolism in human and in rat.

The metabolism of tresperimus, a new immunosuppressive agent, was investigated in vivo and in vitro in rat and in human. Two metabolic pathways were identified at each side of the molecule with two deamination reactions on the spermidine moiety and hydrolysis of the amide bond leading to the liberation of guanidinohexylamine. As the major metabolic pathway of the drug seemed to be the oxidative deamination, the capacity of different amine oxidases to metabolize tresperimus was then tested using in vivo experiments in rat and in vitro studies in rat and human plasma. The increase of tresperimus plasma levels induced by the administration of hydralazine, an irreversible in vivo inhibitor of semicarbazide-sensitive amine oxidase (SSAO), reflected the major involvement of this enzyme in tresperimus metabolism. This result was confirmed in vitro in rat and human plasma by the use of semicarbazide, a specific SSAO inhibitor. As opposed to rat plasma, human plasma may be an interesting in vitro model to study the metabolism of a drug extensively metabolized by SSAO such as tresperimus. Indeed, SSAO activity was significantly higher in human plasma than in rat plasma. The second metabolic pathway of the drug, which only occurred in rat plasma, appeared thus as the major route of tresperimus metabolism in this biological matrix.

Preferential pharmacological inhibition of macrophage ACAT increases plaque formation in mouse and rabbit models of atherogenesis.

The cholesteryl ester, foam cell-enriched vulnerable plaque is a principle pharmacological target for reducing athero-thrombosis. Acyl CoA:cholesterol Acyl Transferase (ACAT) catalyzes the esterification of free cholesterol in intestine, liver, adrenal and macrophages, leading in the latter cells to intracellular cholesteryl ester accumulation and foam cell formation in the arterial intima. Previous studies suggested the existence of several isoforms of ACAT with different tissue distribution and this has largely been confirmed by molecular cloning of ACAT-1 and ACAT-2. We developed a series of ACAT inhibitors that preferentially inhibited macrophage ACAT relative to hepatic or intestinal ACAT based on in vitro assays and ex vivo bioavailability studies. Four of these compounds were tested in three models of atherosclerosis at oral doses shown to give sufficient bioavailable monocyte/macrophage ACAT inhibitory activity. In fat-fed C57BL/6 mice, chow fed apo E-/- mice and KHC rabbits, the various ACAT inhibitors had either no effect or increased indices of atherosclerotic foam cell formation. Direct and indirect measurements suggest that the increase in plaque formation may have been related to inhibition of macrophage ACAT possibly leading to cytotoxic effects due to augmented free cholesterol. These results suggest that pharmacological inhibition of macrophage ACAT may not reduce, but actually aggravate, foam cell formation and progression.

Disposition and exposure of the fibrinogen receptor antagonist XV459 on alphaIIBbeta3 binding sites in the guinea pig.

The disposition of XV459, a potent, selective GP IIb/IIIa antagonist, has been examined following intravenous administration of XP280, the benzenesulphonate salt, and 3H-SA202, the trifluroacetic acid salt, to male guinea pigs. A liquid chromatography-mass spectrometry (LC-MS) method was developed and validated for XV459 quantitation in guinea pig plasma with an LLOQ of 0.1 ng/mL. Intravenous infusions (30 min) of XP280 at doses of 0.5 and 2.0 microg/kg were administered to guinea pigs which were sequentially sacrificed at 0.5, 1, 1.5, 4, 8, 12, 24, 48 and 72 h postinitiation of infusion. Maximum total (unbound and GP IIb/IIIa displaced) XV459 plasma concentration of approximately 3.5 microg/mL was obtained at the 2.0 microg/kg dose. Pooling individual concentration-time data yielded a systemic clearance of 1.42 mL/min/kg, Vss of 0.24 L/kg, and a terminal half-life of 2.8 h in the guinea pig at the 0.5 microg/kg dose. The 2.0 microg/kg dose yielded XV459 exposure that was less than proportional to the previous dose. Similar behaviour has been observed in human trials. Cumulative (up to 72 h) urinary and faecal recovery of total radioactivity was 66.4 and 11.2%, respectively. The time course of spleen, marrow and whole blood radioactivity profiles was similar, suggesting that XV459 was not preferentially sequestered on non-plasma GP IIb/IIIa binding sites. Tissue to blood ratios of 20.7 and 8.3 for the spleen and bone marrow, respectively, indicate that increased (relative to blood) exposure was evident for sites containing the GP IIb/IIIa receptor. In vitro studies confirmed the similarity of XV459 binding to both resting and activated platelets in the guinea pig and humans. Given the comparability of dissociation rate constants and IC50s based on in vitro platelet aggregation, human dosimetry estimates should assume similar partitioning of radiolabelled XV459 as in the guinea pig. These results suggest that the guinea pig may indeed be an appropriate animal model for pharmacokinetic and distribution studies with DMP754; in conjunction with recent pharmacological findings with GP IIb/IIIa antagonists, our results suggest that the guinea pig may be the rodent species of choice for preclinical studies with some other GP IIb/IIIa antagonists.

Biological matrix-dependent pharmacokinetic and pharmacodynamic parameters of a novel platelet glycoprotein IIB/IIIA receptor antagonist, XU063, in beagle dogs.

The pharmacokinetic-pharmacodynamic (PK/PD) relationship of a novel platelet glycoprotein IIb/IIIa receptor antagonist, XU063, was evaluated as a function of biological matrix in beagle dogs. The disposition of 14C-radioactivity in various blood or plasma matrices and kinetics of inhibition of adenosine diphosphate (ADP) induced platelet aggregation were determined in beagle dogs following an intravenous infusion of 14C-XU063 at 2 micrograms/kg for 45 min. The 14C-radioactivity was maximum in platelet poor plasma (PPP) harvested from blood collected in EDTA and lowest in PPP harvested from blood collected in citrated vacutainers over the entire concentration versus time profile during and post infusion. The 14C-radioactivity values in blood and platelet rich plasma (PRP) were comparable and were between EDTA PPP and citrated PPP values. The resultant estimates of the PK and PD parameters of 14C-XU063 varied widely depending on the type of matrix used. The systemic clearance values for 14C-XU063 were 1 and 10 mL/min/kg for EDTA and citrated PPP, respectively. The values for the volume of distribution at steady-state were 0.2 and 1.3 L/kg, for EDTA and citrated PPP, respectively. The terminal elimination half-life appeared independent of the matrix with a median value of 2 h. The estimated ex vivo IC50 values of XU063 ranged from 0.4 ng/mL (citrated PPP, platelet free drug) to 7 ng/mL (EDTA PPP, total drug). These results demonstrated the dependence of PK and PD parameters of antiplatelet agent XU063 on the type of biological matrix used to determine concentrations of XU063. The pros and cons of various blood sample collection methods for the evaluation of PK/PD relationship of potential antiplatelet agents are presented.

Age-related increase of baseline frequencies of sister chromatid exchanges, chromosome aberrations, and micronuclei in human lymphocytes.

Intra- and interindividual variations of baseline frequencies of cytogenetic end points in lymphocytes of human populations have been reported by various authors. Personal characteristics seem to account for a significant proportion of this variability. Several studies investigating the role of age as a confounding factor in cytogenetic biomonitoring found an age-related increase of micronucleus (MN) frequency, whereas contradictory results were reported for chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs). We have quantitatively evaluated the effect of age on SCE, CA, and MN through the analysis of a population sample that included data from several biomonitoring studies performed over the last few decades in 12 Italian laboratories. The large size of the data set, i.e., more than 2000 tests for each end point, allowed us to estimate the independent effect of age, taking into account other covariates, such as sex, smoking habits, occupational exposure, and inter- and intralaboratory variability. A greater frequency of the mean standardized values by increasing of age was observed for all of the end points. A leveling off was evident in the last age classes in the trend of MN frequencies. Frequency ratios (FRs), which express the increase of the cytogenetic damage with respect to the first age classes, i.e., 1-19 years, were estimated using Poisson regression analysis after adjustment for the potential confounding factors and confirmed the increasing trend by age class for all three end points. The most dramatic increase was observed for MN, with a FR that approaches the value of 2 at the age class 50-59 (FR, 1.97; 95% confidence interval, 1.43-2.71) and remains substantially unchanged thereafter. The trend of FRs for CA is more homogeneous, with a constant rise even in the older classes, whereas the frequency of SCE increases with age to a lesser extent, reaching a plateau in the age class 40-49 and the maximum value of FR in the age class over 70 (FR, 1.14; 95% confidence interval, 1.07-1.23). In conclusion, our results point to an age-related increase of the chromosome damage in lymphocytes and emphasize the need to take into account the potential confounding effect of this variable in the design of biomonitoring studies based on chromosome damage.

Chromosome aberrations in hospital workers: evidence from surveillance studies in Italy (1963-1993).

Hospital workers are occupationally exposed to various agents known or suspected to induce chromosome damage, the most studied being ionizing radiation. To determine the extent of chromosome damage in peripheral blood lymphocytes in this population, taking into account temporal changes and job titles, a re-analysis of cytogenetic studies performed in four Italian laboratories in the period 1965-1993 was carried out. A total of 871 hospital workers and 617 controls, mainly coming from ad hoc studies or surveillance programs in occupational groups potentially exposed to ionizing radiation, were examined. The exposed to controls frequency ratio of chromosome aberrations was evaluated as the measure of effect within each dataset by job title, using multivariate Poisson regression analysis, which allowed an efficient control of confounding. Increased frequency of chromosome-type aberrations among exposed subjects was found in all datasets, especially in those dealing with older data. Significantly higher frequencies are reported for various job titles, particularly for orthopedists, radiologists, anesthesists, and nurses among paramedical occupations. Decrease in exposure to ionizing radiation in hospital workers was documented through a targeted study in the critical group of radiologists. A similar time-related reduction in the frequency of chromosome-type aberrations also has been reported by the surveillance studies carried out over the most recent decades. These data substantiate the use of chromosome-type aberrations as biomarkers of exposure in this occupational setting in the period evaluated. However, the increases observed also in workers with doubtful exposure to ionizing radiation indicate that other chromosome-damaging agents may be involved and, in turn, suggest the extension of surveillance to a larger number of occupations.

Determination of a novel cognitive enhancer, X9121, and its mono N-oxide metabolite, XG696, in dog plasma by reversed-phase high-performance liquid chromatography with ultraviolet detection.

A selective and sensitive high-performance liquid chromatographic assay for a novel cognitive enhancer, X9121 (I), and its mono N-oxide metabolite, XG696 (II), in dog plasma has been developed. Compounds I, II and internal standard (I.S.) were first extracted from dog plasma using a solid-phase Bond Elut Certify I 10-ml LRC reservoir extraction cartridge. Chromatographic separation of I, II and I.S. was conducted on a reversed-phase Zorbax Stable Bond cyano column. Ammonium acetate buffer (0.05 M, pH 6)-acetonitrile-triethylamine (75:25:0.1, v/v) was used as the mobile phase. Detection of all three compounds was by UV light absorbance at 313 nm. Using 0.5 ml of dog plasma for extraction, the minimum quantifiable limit was 10 ng/ml and the assay was linear from 10 to 5400 ng/ml. The coefficients of variation for intra-day precision ranged from 2.2 to 8.5% for I and from 2.5 to 9.8% for II. The coefficients of variation for the inter-day precision for these two compounds ranged from 2.6 to 9.0% and from 3.6 to 16.2%, respectively. The absolute percent differences for the accuracy results were within 11.0% of the spiked concentrations. Compounds I and II were stable in frozen plasma at -20 degrees C for at least 67 days.

Are chromosome aberrations in circulating lymphocytes predictive of future cancer onset in humans? Preliminary results of an Italian cohort study.

To investigate the existence of an association between the frequency of chromosome aberrations (CA) in non-target tissues and cancer risk, a historical cohort study was carried out in a group of 1455 subjects screened for CA over the last 20 years in Italy. Statistically significant increases in standardized mortality ratio (SMR) for all cancers were found in subjects with medium and high levels of CA in peripheral blood lymphocytes (SMR = 178.5 and SMR = 182.0, respectively) and in subjects with high levels of CA for respiratory tract cancers (SMR = 250.8) and lymphatic and hematopoietic tissue neoplasms (SMR = 548.8). Significant trends in the SMRs were observed for these latter causes of death.

Determination of DMP 728, a IIb/IIIa receptor antagonist, in rat and dog plasma by high-performance liquid chromatography with fluorimetric detection.

A specific and sensitive HPLC assay for the determination of DMP 728 in dog and rat plasma has been developed. The method involves solid-phase extraction of DMP 728 and the internal standard from plasma using a C2 column. The extracted compounds are derivatized with benzoin under alkaline conditions. Using a mixture of acetonitrile and 0.1 M potassium phosphate buffer (25:75, v/v, pH 7.4) as mobile phase, the derivatized products are separated on a Regis semipermeable surface C8 column and monitored fluorometrically using 325 nm and 425 nm as excitation and emission wavelengths, respectively. The assay is linear from 2.5 to 1000 ng/ml in dog plasma and from 5 to 1000 ng/ml in rat plasma. The limit of quantitation is 2.5 ng/ml using 0.5 ml of dog plasma and 5 ng/ml using 0.5 ml of rat plasma. The assay has been used in pharmacokinetic studies of DMP 728 in dogs and rats.

Effect of the nonsteroidal antiandrogen nilutamide on adrenal androgen secretion.

The nonsteroidal androgen-receptor antagonist nilutamide has previously been shown to inhibit adrenal androgen steroidogenesis in patients with prostatic carcinoma treated in combination with an LHRH agonist. In order to understand better the mechanisms subserving this observation, we have studied the effects of nilutamide alone on the serum concentrations of androstenedione (A), dehydroepiandrosterone (DHEA), and DHEA-sulphate (DHEA-S) in 12 patients with prostatic cancer and compared them with those achieved in 21 patients treated with the agonist D-Trp-6-LHRH. In addition, the adrenocorticotropic hormone (ACTH)-stimulated adrenal response and the thyrotropin releasing hormone (TRH)-stimulated prolactin (PRL) response observed in the patients treated with nilutamide were compared with a control group of healthy age-matched controls. No significant variation in the basal concentrations of adrenal androgens occurred either within or between both treatment groups. In response to ACTH, a decreased 17-alpha hydroxyprogesterone (17-OHP) accumulation and an augmented A/17-OHP ratio were observed in the antiandrogen group (P < 0.05 for both), suggesting the partial removal of the 17,20 lyase block which was distinctive of the untreated controls, while no significant difference was found for other steroids. Basal PRL levels were not affected by the antiandrogen, but the response to TRH was increased. We conclude that no significant inhibition of adrenal androgen secretion occurs after nilutamide or LHRH agonist treatment. Rather, administration of the antiandrogen alone may partially remove the physiological decrease in adrenal androgen secretion observed in the elderly.

Long-term endocrine effects of administration of either a non-steroidal antiandrogen or a luteinizing hormone-releasing hormone agonist in men with prostate cancer.

The claimed ability of non-steroidal antiandrogens to preserve libido and sexual potency is sought as a potential improvement in the palliative management of prostate cancer. A critical issue for the clinical use of these compounds is, however, the reported evidence in the rat of an excessive increase in testosterone concentrations as a consequence of the androgen negative feedback interruption. On the other hand, the recovery of testicular function after long-term inhibition by luteinizing hormone-releasing hormone (LHRH) analogs is also an important concern in view of the proposed use of these compounds for the treatment of several non-malignant conditions. We addressed these issues by studying the long-term endocrine effects induced by the administration of either the non-steroidal antiandrogen nilutamide or the depot preparation of D-Trp6-LHRH in men with prostate cancer. Treatment with the antiandrogen induced a marked increase in gonadotropin levels, LH concentrations rising from a mean (SEM) of 17.5 +/- 1.6 to a maximum of 56.6 +/- 6.9 kU/l (p < 0.001), while mean testosterone and 17 beta estradiol-concentrations rose only by about 50% and 70% over pretreatment values, testosterone levels reaching a plateau after 1 month of treatment. In the subjects treated with the LHRH agonist, 6 months after discontinuation of long-term administration the mean (+/- SEM) LH had risen to 36.9 +/- 6.8 IU/l while mean testosterone levels were still as low as 1.7 +/- 0.7 and rose only to a maximum of 4.2 +/- 1 nmol/l after high-dose human chorionic gonadotropin loadings.(ABSTRACT TRUNCATED AT 250 WORDS)

Nanogram level quantitation of oxycodone in human plasma by capillary gas chromatography using nitrogen-phosphorus selective detection.

A sensitive and specific capillary gas chromatographic assay is reported for the quantitation of oxycodone in human plasma. The technique involves a single extraction of oxycodone and internal standard (hydrocodone) from plasma by toluene containing 1% isopropanol. Separation is achieved on a methyl silicone (HP-1) fused-silica capillary column (25 m x 0.2 mm I.D., 0.33 microns film thickness) and detection is by nitrogen-phosphorus selective mode. The minimum quantifiable limit is 1.8 ng/ml using 2 ml of plasma. The method is applicable to characterize the plasma profile of oxycodone in humans after a single oral 5-mg oxycodone hydrochloride tablet.

Central nervous system involvement during infection by Phlebovirus toscana of residents in natural foci in central Italy (1977-1988).

Central nervous system (CNS) involvement was detected during infection caused by the sand fly-transmitted Phlebovirus Toscana. One hundred fifty-five cases of Toscana virus-associated meningitis or meningoencephalitis were identified in a survey that lasted ten years, conducted in two regions of central Italy. Diagnosis was performed by different serologic tests. A combination of hemagglutination-inhibition and plaque-reduction neutralization or indirect immunofluorescence for IgM, and enzyme-linked immunosorbent assays for IgM were considered the most suitable tests for the diagnosis of Toscana virus infection. A few strains of Toscana virus were isolated from the cerebrospinal fluid of seropositive patients. Toscana virus-associated CNS disease occurred during the summer, reaching a peak value in August, when the maximum activity of the sand fly vector occurs and virus isolates are obtained in their natural foci. The results suggest that Toscana virus should be considered as a possible cause of CNS disease in Mediterranean countries where sand flies of the genus Phlebotomus are known to be present.

A preliminary metabolic study of alpidem in rat and man.

The metabolism of alpidem, a new anxiolytic agent in the chemical series of imidazopyridines, was investigated in rat and man. In both species the compound is extensively metabolised by three main routes of biotransformation: aromatic oxidation of the imidazopyridine ring; n-dealkylation; and/or aliphatic oxidation of the substituted amide side chains.

Pharmacokinetic interactions of progabide with other antiepileptic drugs.

The influence of progabide, a new antiepileptic drug, on the pharmacokinetic profiles of phenobarbital, phenytoin, carbamazepine, and valproic acid was evaluated in four separate studies, each including six young healthy volunteers. The pharmacokinetic parameters of the associated antiepileptic drugs were measured before and after repeated administration of progabide (600 mg t.i.d.) for 15 days. A significant reduction of the total body clearance of both phenytoin and phenobarbital and a higher Cmax value of carbamazepine epoxide and phenobarbital were observed. No modifications were noticed for the kinetic profiles of carbamazepine and valproic acid. These modifications may be of clinical relevance and suggest that, as a general rule, when progabide is added to an established treatment with phenobarbital or phenytoin or carbamazepine, an adjustment of previous posology may be necessary.

Determination of progabide and its main acid metabolite in biological fluids using high-performance liquid chromatography and electrochemical detection. Application to the measurement of blood/plasma partition ratio.

A method for the measurement in plasma, blood and urine of progabide, its main acid metabolite, and the corresponding benzophenone is described. This assay allows the determination of progabide and its acid metabolite for therapeutic drug monitoring, and with a minimum detectable concentration of 1-10 ng/ml for progabide and its acid metabolite, it is sensitive enough for pharmacokinetic studies. Progabide and its metabolites are extracted from biological samples with toluene at pH 4.5. Following reduction of the imine bond with sodium borohydride, the reduced drugs are back-extracted into an aqueous phase at acid pH and reextracted by diethyl ether at alkaline pH. Progabide, its acid metabolite and the benzophenone are separated by high-performance liquid chromatography using a 3-micron ODS column with a quaternary solvent mixture of methanol-acetonitrile-phosphate buffer (0.033 M, pH 5.5)-sodium chloride (1.5 M) (30:30:40:9, v/v), and detected electrochemically at a potential of +850 mV vs. an Ag/AgCl electrode. Antiepileptic drugs like carbamazepine, carbamazepine epoxide, phenytoin, valproic acid and ethosuximide do not interfere with the assay. Blood/plasma partition ratios of 0.69 and 0.55 for progabide and its acid metabolite, respectively, indicate that the former but not the latter is present in red blood cells.